bioengineering-humanized-bone-marrow-microenvironments-mouse-their

Bioengineering of Humanized Bone Marrow Microenvironments in Mouse and Their Visualization by Live Imaging

Human hematopoietic stem cells (HSCs) reside in the bone marrow (BM) niche, an intricate, multifactorial network of components producing cytokines, growth ...

The Francis Crick Institute

Lymphknoten (LN) Entwicklung h&auml;ngt eine vorgeburtliche Interaktionen zwischen LN Induktor und LN Veranstalter Zellen. Wir haben M&auml;ngel in LN-Formation aufgrund eines Fehlers in der embryonalen Entwicklung (aly/aly) von Defekten in postnatale Reifung (Il2rgamma(-/-)Rag2(-/-)). unterschieden. Beide mutierte St&auml;mme bilden normale primordial LNs mit unterschiedlichen Schicksal. Aly/aly M&auml;usen zerstreut die LN-Urzeit irreversibel sp&auml;t in der Schwangerschaft; im Gegensatz dazu Il2rgamma(-/-)Rag2(-/-) LN-Anlage wird f&uuml;r eine Woche nach der Geburt aber zerstreut sich anschlie&szlig;end ein Prozess reversibel durch neonatale &Uuml;bertragung von WT IL7r(+) TCR(+) T oder nat&uuml;rlichen killer (NK) Zellen, schl&auml;gt eine Rolle f&uuml;r IL7/IL7r Interaktionen. So enth&uuml;llen wir eine einzigartige Entwicklungsstand postnatale LN in der Reife Lymphozyten und IL7/IL7r Interaktionen eine wichtige Rolle spielen k&ouml;nnen.

Rolle des T- und NK-Zellen und IL7/IL7r Interaktionen w&auml;hrend neonatale Reifung der Lymphknoten.

Linfonodo (LN) sviluppo dipende prenatale interazioni che si verificano tra induttore LN e LN Organizzatore celle. Noi abbiamo distinto difetti nella formazione LN a causa di insufficienza nello sviluppo embrionale (aly/aly) da difetti di maturazione postnatale (Il2rgamma(-/-)Rag2(-/-)). Entrambi i ceppi mutanti formano normale LNs primordiale con destino diverso. Nei topi aly/aly, i primordi LN dissipa irreversibilmente in ritardo nella gestazione; in contrasto, anlage Il2rgamma(-/-)Rag2(-/-) LN persiste per una settimana dopo la nascita, ma successivamente, disperde un reversibile processo di trasferimento neonatale di WT IL7r(+) TCR(+) T o di naturale cellule killer (NK), suggerendo un ruolo per le interazioni IL7/IL7r. Cos&igrave;, ci rivelano un unico stadio di postnatale LN sviluppo, durante la quale linfociti maturi e IL7/IL7r interazioni possono svolgere un ruolo importante.

Ruolo delle cellule T e NK e IL7/IL7r interazioni durante la maturazione neonatale dei linfonodi.

&#x30EA;&#x30F3;&#x30D1;&#x7BC0; (LN) &#x958B;&#x767A; LN &#x30A4;&#x30F3;&#x30C7;&#x30E5;&#x30FC;&#x30B5;&#x3068; LN &#x30AA;&#x30FC;&#x30AC;&#x30CA;&#x30A4;&#x30B6;&#x30FC;&#x7D30;&#x80DE;&#x9593;&#x767A;&#x751F;&#x3057;&#x3066;&#x51FA;&#x751F;&#x524D;&#x306E;&#x76F8;&#x4E92;&#x4F5C;&#x7528;&#x306B;&#x3088;&#x3063;&#x3066;&#x7570;&#x306A;&#x308A;&#x307E;&#x3059;&#x3002;&#x79C1;&#x305F;&#x3061;&#x80DA;&#x767A;&#x751F; (aly/aly) &#x3067;&#x969C;&#x5BB3;&#x306B;&#x3088;&#x308B; LN &#x5F62;&#x6210;&#x306B;&#x304A;&#x3051;&#x308B;&#x6B20;&#x9665;&#x6B20;&#x9665;&#x306E;&#x751F;&#x5F8C;&#x6210;&#x719F; (Il2rgamma(-/-)Rag2(-/-))&#x3002; &#x533A;&#x5225;&#x3092;&#x6301;&#x3063;&#x3066;&#x4E21;&#x5909;&#x7570;&#x682A;&#x901A;&#x5E38;&#x539F;&#x59CB; LNs &#x7570;&#x306A;&#x308B;&#x904B;&#x547D;&#x3092;&#x5F62;&#x6210;&#x3057;&#x307E;&#x3059;&#x3002;Aly/aly &#x30DE;&#x30A6;&#x30B9;&#x3067; LN &#x539F;&#x57FA;&#x306F;&#x4E0D;&#x53EF;&#x9006;&#x7684;&#x5F8C;&#x671F;&#x598A;&#x5A20;&#x3067;&#x6563;&#x308B;;&#x5BFE;&#x7167;&#x7684;&#x306B;&#x3001;Il2rgamma(-/-)Rag2(-/-) LN &#x539F;&#x57FA;&#x751F;&#x5F8C;&#x5F8C; 1 &#x9031;&#x9593;&#x7D9A;&#x304F;&#x304C;&#x3001;&#x305D;&#x306E;&#x5F8C;&#x3001;&#x30D7;&#x30ED;&#x30BB;&#x30B9;&#x53EF;&#x9006; WT IL7r(+) TCR(+) T &#x307E;&#x305F;&#x306F;&#x30CA;&#x30C1;&#x30E5;&#x30E9;&#x30EB; &#x30AD;&#x30E9;&#x30FC; (NK) &#x7D30;&#x80DE;&#x306E; IL7/IL7r &#x306E;&#x76F8;&#x4E92;&#x4F5C;&#x7528;&#x306E;&#x5F79;&#x5272;&#x3092;&#x793A;&#x5506;&#x65B0;&#x751F;&#x5150;&#x8EE2;&#x9001;&#x306B;&#x3088;&#x3063;&#x3066;&#x5206;&#x6563;&#x3055;&#x305B;&#x307E;&#x3059;&#x3002;&#x3057;&#x305F;&#x304C;&#x3063;&#x3066;&#x3001;&#x3069;&#x306E;&#x6210;&#x719F;&#x30EA;&#x30F3;&#x30D1;&#x7403;&#x304A;&#x3088;&#x3073; IL7/IL7r &#x4E2D;&#x306B;&#x76F8;&#x4E92;&#x4F5C;&#x7528;&#x304C;&#x91CD;&#x8981;&#x306A;&#x5F79;&#x5272;&#x3092;&#x679C;&#x305F;&#x3059;&#x53EF;&#x80FD;&#x6027;&#x304C;&#x3042;&#x308A;&#x307E;&#x3059;&#x7523;&#x5F8C;&#x306E; LN &#x958B;&#x767A;&#x306E;&#x30E6;&#x30CB;&#x30FC;&#x30AF;&#x306A;&#x6BB5;&#x968E;&#x3092;&#x660E;&#x3089;&#x304B;&#x306B;&#x3057;&#x307E;&#x3059;&#x3002;

T &#x304A;&#x3088;&#x3073; NK &#x7D30;&#x80DE;&#x3068;&#x30EA;&#x30F3;&#x30D1;&#x7BC0;&#x306E;&#x65B0;&#x751F;&#x5150;&#x306E;&#x6210;&#x719F;&#x306B;&#x4F34;&#x3046; IL7/IL7r &#x76F8;&#x4E92;&#x4F5C;&#x7528;&#x306E;&#x5F79;&#x5272;

&#x6DCB;&#x5DF4;&#x7ED3; (LN) &#x53D1;&#x5C55;&#x53D6;&#x51B3;&#x4E8E;&#x4EA7;&#x524D; LN &#x8BF1;&#x5BFC;&#x56E0;&#x5B50;&#x548C; LN &#x4E3B;&#x529E;&#x5355;&#x4F4D;&#x7EC6;&#x80DE;&#x4E4B;&#x95F4;&#x53D1;&#x751F;&#x7684;&#x76F8;&#x4E92;&#x4F5C;&#x7528;&#x3002;&#x6211;&#x4EEC;&#x533A;&#x5206;&#x4E86; LN &#x5F62;&#x6210;&#x6545;&#x969C; (aly/aly) &#x80DA;&#x80CE;&#x53D1;&#x80B2;&#x7F3A;&#x9677;&#x7684;&#x7F3A;&#x9677;&#xFF0C;&#x5728;&#x4EA7;&#x540E;&#x6210;&#x719F; (Il2rgamma(-/-)Rag2(-/-))&#x3002;&#x8FD9;&#x4E24;&#x79CD;&#x7A81;&#x53D8;&#x682A;&#x5F62;&#x6210;&#x6B63;&#x5E38;&#x7684;&#x539F;&#x59CB; LNs&#xFF0C;&#x4E0D;&#x540C;&#x7684;&#x547D;&#x8FD0;&#x3002;&#x963F;&#x91CC;/&#x963F;&#x91CC;&#x5C0F;&#x9F20;&#xFF0C;LN &#x666E;&#x5229;&#x6D88;&#x6563;&#x4E0D;&#x53EF;&#x9006;&#x8F6C;&#x5730;&#x665A;&#x598A;&#x5A20; &#xFF1B;&#x76F8;&#x6BD4;&#x4E4B;&#x4E0B;&#xFF0C;Il2rgamma(-/-)Rag2(-/-) LN &#x7D20;&#x8D28;&#x51FA;&#x751F;&#x540E;&#x4E00;&#x5468;&#x4ECD;&#x7136;&#x5B58;&#x5728;&#xFF0C;&#x4F46;&#x968F;&#x540E;&#xFF0C;&#x6563;&#x7531;&#x65B0;&#x751F;&#x513F;&#x8F6C;&#x8BA9; WT IL7r(+) TCR(+) T &#x6216;&#x81EA;&#x7136;&#x6740;&#x624B; (NK) &#x7EC6;&#x80DE;&#xFF0C;&#x6697;&#x793A; IL7/IL7r &#x4EA4;&#x4E92;&#x4F5C;&#x7528;&#x7684;&#x8FC7;&#x7A0B;&#x53EF;&#x9006;&#x3002;&#x56E0;&#x6B64;&#xFF0C;&#x6211;&#x4EEC;&#x63ED;&#x793A;&#x72EC;&#x7279;&#x53D1;&#x5C55;&#x9636;&#x6BB5;&#x7684;&#x4EA7;&#x540E; LN &#x671F;&#x95F4;&#x54EA;&#x4E9B;&#x6210;&#x719F;&#x6DCB;&#x5DF4;&#x7EC6;&#x80DE;&#x548C; IL7/IL7r &#x76F8;&#x4E92;&#x4F5C;&#x7528;&#x53EF;&#x80FD;&#x53D1;&#x6325;&#x91CD;&#x8981;&#x4F5C;&#x7528;&#x3002;

T &#x548C; NK &#x7EC6;&#x80DE;&#x548C; IL7/IL7r &#x76F8;&#x4E92;&#x4F5C;&#x7528;&#x7684;&#x6DCB;&#x5DF4;&#x7ED3;&#x65B0;&#x751F;&#x513F;&#x53D1;&#x80B2;&#x8FC7;&#x7A0B;&#x7684;&#x4F5C;&#x7528;&#x3002;

Lymph node (LN) development depends on prenatal interactions occurring between LN inducer and LN organizer cells. We have distinguished defects in LN formation due to failure in embryonic development (aly/aly) from defects in postnatal maturation (Il2rgamma(-/-)Rag2(-/-)). Both mutant strains form normal primordial LNs with differing fate. In aly/aly mice, the LN primordium dissipates irreversibly late in gestation; in contrast, Il2rgamma(-/-)Rag2(-/-) LN anlage persists for a week after birth but disperses subsequently, a process reversible by neonatal transfer of WT IL7r(+) TCR(+) T or natural killer (NK) cells, suggesting a role for IL7/IL7r interactions. Thus, we reveal a unique stage of postnatal LN development during which mature lymphocytes and IL7/IL7r interactions may play an important role.

Role of T and NK cells and IL7/IL7r interactions during neonatal maturation of lymph nodes.

Ganglions lymphatiques (LN) d&eacute;veloppement d&eacute;pend prenatal interactions se produisant entre inducteur LN et cellules organisateur LN. Nous avons distingu&eacute; les d&eacute;fauts dans la formation de LN en raison de l&#39;&eacute;chec dans le d&eacute;veloppement embryonnaire (aly/aly) contre tout d&eacute;faut de maturation postnatale (Il2rgamma(-/-)Rag2(-/-)). Les deux souches mutantes forment normales LNs primordiales avec diff&eacute;rente sort. Chez les souris aly/aly, le primordium LN dissipe irr&eacute;versiblement tard en gestation ; en revanche, anlage Il2rgamma(-/-)Rag2(-/-) LN persiste pendant une semaine apr&egrave;s la naissance mais disperse par la suite, un r&eacute;versible de processus de transfert n&eacute;onatal de WT IL7r(+) TCR(+) T ou cellules tueuses naturelles de (NK), sugg&eacute;rant un r&ocirc;le pour les interactions IL7/IL7r. Ainsi, nous r&eacute;v&egrave;lent un stade unique de d&eacute;veloppement postnatal de LN pendant laquelle les lymphocytes matures et IL7/IL7r interactions peuvent jouer un r&ocirc;le important.

R&ocirc;le des cellules T et NK et des interactions de IL7/IL7r au cours de la maturation n&eacute;onatale des ganglions lymphatiques.

&#xB9BC;&#xD504; &#xB178;&#xB4DC; (LN) &#xAC1C;&#xBC1C; LN &#xC720;&#xB3C4; &#xBC0F; LN &#xC8FC;&#xCD5C;&#xC790; &#xC140; &#xC0AC;&#xC774; &#xBC1C;&#xC0DD; &#xD558;&#xB294; &#xD0DC;&#xC544; &#xC0C1;&#xD638; &#xC791;&#xC6A9;&#xC5D0; &#xB530;&#xB77C; &#xB2EC;&#xB77C; &#xC9D1;&#xB2C8;&#xB2E4;. &#xC6B0;&#xB9AC; &#xC0B0; &#xD6C4; &#xC131;&#xC219; (Il2rgamma(-/-)Rag2(-/-)) &#xAE30;&#xC220;&#xC5D0; &#xBC30;&#xC544; &#xAC1C;&#xBC1C; (aly/aly) &#xC624;&#xB958;&#xB85C; &#xC778;&#xD574; LN &#xD615;&#xC131;&#xC5D0; &#xACB0;&#xD568;&#xC744; &#xAD6C;&#xBCC4; &#xD574;&#xC57C;. &#xB450; &#xB3CC;&#xC5F0;&#xBCC0;&#xC774; &#xC885;&#xC790; &#xD615;&#xC131; &#xAC01;&#xAE30; &#xB2E4;&#xB978; &#xC6B4;&#xBA85;&#xACFC; &#xC815;&#xC0C1;&#xC801;&#xC778; &#xC6D0;&#xC2DC; LNs. Aly aly &#xC0DD;&#xC950;&#xC5D0;&#xC11C; LN primordium irreversibly &#xB2A6;&#xAC8C; &#xC784;&#xC2E0;;&#xC5D0;&#xC11C; &#xC5C6;&#xC5B4;&#xC838; &#xB300;&#xC870;&#xC801;&#xC73C;&#xB85C;, Il2rgamma(-/-)Rag2(-/-) LN &#xC704;&#xCE58; &#xCD9C;&#xC0B0; &#xD6C4; &#xC77C;&#xC8FC;&#xC77C; &#xB3D9;&#xC548; &#xC9C0;&#xC18D; &#xD558;&#xC9C0;&#xB9CC; &#xD504;&#xB85C;&#xC138;&#xC2A4; &#xAC00;&#xC5ED; WT IL7r(+) TCR(+) T &#xB610;&#xB294; &#xC790;&#xC5F0; &#xD0AC;&#xB7EC; (NK) &#xC138;&#xD3EC;&#xC758; &#xC2E0;&#xC0DD;&#xC544; &#xC804;&#xC1A1; IL7/IL7r &#xC0C1;&#xD638; &#xC791;&#xC6A9;&#xC5D0; &#xB300; &#xD55C; &#xC5ED;&#xD560;&#xC744; &#xC81C;&#xC548; &#xD558; &#xC5EC; &#xADF8; &#xD6C4;, &#xBD84; &#xAD11;. &#xB530;&#xB77C;&#xC11C;, &#xC6B0;&#xB9AC;&#xB294; &#xC131;&#xC219; &#xC138;&#xD3EC; &#xBC0F; IL7/IL7r &#xB3D9;&#xC548; &#xC0C1;&#xD638; &#xC791;&#xC6A9; &#xC911;&#xC694; &#xD55C; &#xC5ED;&#xD560;&#xC744; &#xC7AC;&#xC0DD;&#xD560; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4; &#xC0B0; &#xD6C4; LN &#xAC1C;&#xBC1C;&#xC758; &#xB3C5;&#xD2B9;&#xD55C; &#xBB34;&#xB300; &#xACF5;&#xAC1C;.

T&#xC640; NK &#xC138;&#xD3EC;&#xC640; &#xB9BC;&#xD504;&#xC808;&#xC758; &#xC2E0;&#xC0DD;&#xC544; &#xC131;&#xC219; &#xD558;&#xB294; &#xB3D9;&#xC548; IL7/IL7r &#xC0C1;&#xD638; &#xC791;&#xC6A9;&#xC758; &#xC5ED;&#xD560;.

Desarrollo del nodo de linfa (LN) depende de prenatales interacciones que ocurren entre LN inductor y c&eacute;lulas del organizador de LN. Nos hemos distinguido defectos en la formaci&oacute;n de LN debido a un fallo en el desarrollo embrionario (aly/aly) de defectos en la maduraci&oacute;n postnatal (Il2rgamma(-/-)Rag2(-/-)). Ambas cepas mutantes forman normal LNs primordial con destino diferente. En ratones aly/aly, el primordio LN se disipa irremediablemente tarde en gestaci&oacute;n; por el contrario, anlage Il2rgamma(-/-)Rag2(-/-) LN persiste durante una semana despu&eacute;s del nacimiento, pero posteriormente, dispersa una reversible proceso por transferencia neonatal de WT IL7r(+) TCR(+) T o c&eacute;lulas de asesinas naturales del (NK), sugiriendo un papel para las interacciones IL7/IL7r. As&iacute;, nos revelan una &uacute;nica etapa del desarrollo postnatal de la LN en que linfocitos maduros y IL7/IL7r interacciones pueden desempe&ntilde;ar un papel importante.

Papel de las c&eacute;lulas T y NK y IL7/IL7r interacciones durante la maduraci&oacute;n neonatal de los ganglios linf&aacute;ticos.

&#x6B63;&#x5E38;&#x5668;&#x5B98;&#x53D1;&#x751F;&#x9700;&#x8981;&#x7EDF;&#x7B79;&#x53D1;&#x5C55;&#x548C;&#x4E92;&#x52A8;&#x7684;&#x591A;&#x4E2A;&#x5355;&#x5143;&#x683C;&#x7C7B;&#x578B;&#xFF0C;&#x548C;&#x770B;&#x4F3C;&#x53D7;&#x7EC4;&#x7EC7;&#x5177;&#x4F53;&#x56E0;&#x7D20;&#x3002;&#x6DCB;&#x5DF4;&#x5668;&#x5B98;&#x53D1;&#x751F;&#x671F;&#x95F4;&#x80DA;&#x80CE;&#x751F;&#x547D;&#x662F;&#x4F9D;&#x8D56;&#x4E8E;&#x5206;&#x5B50;&#x5176;&#x4E2D;&#x7684;&#x65F6;&#x5E8F;&#x8868;&#x8FBE;&#x5B9E;&#x884C;&#x4E25;&#x683C;&#x7BA1;&#x5236;&#x3002;&#x5728;&#x6B64;&#x8FC7;&#x7A0B;&#x4E2D;&#xFF0C;&#x8BF1;&#x5BFC;&#x9020;&#x8840;&#x7EC6;&#x80DE;&#x4E0E;&#x57FA;&#x8D28;&#x7684;&#x7EC4;&#x7EC7;&#x8005;&#x7EC6;&#x80DE;&#xFF0C;&#x5F15;&#x8D77;&#x6DCB;&#x5DF4;&#x5668;&#x5B98;&#x539F;&#x57FA;&#x4EA4;&#x4E92;&#x3002;&#x5728;&#x8FD9;&#x91CC;&#x6211;&#x4EEC;&#x8868;&#x660E;&#x9020;&#x8840;&#x7EC6;&#x80DE;&#x5728;&#x80A0;&#x5C55;&#x54C1;&#x524D;&#x805A;&#x96C6;&#x5230;&#x539F;&#x57FA;&#x7684;&#x5C0F;&#x80A0;&#x7684;&#x4FEE;&#x8865;&#x7A0B;&#x5E8F;&#x3001; &#x80A0;&#x9053;&#x76F8;&#x5173;&#x6DCB;&#x5DF4;&#x7EC4;&#x7EC7;&#x7684;&#x4E00;&#x4E2A;&#x4E3B;&#x8981;&#x7EC4;&#x6210;&#x90E8;&#x5206;&#x7684;&#x52A8;&#x529B;&#x968F;&#x673A;&#x6A21;&#x5F0F;&#x3002;&#x6211;&#x4EEC;&#x8FDB;&#x4E00;&#x6B65;&#x8868;&#x660E;&#xFF0C;CD45 + CD4-CD3-Il7Ralpha-c-&#x5DE5;&#x5177;&#x5305; + CD11c + &#x9020;&#x8840;&#x8868;&#x793A;&#x6DCB;&#x5DF4;&#x7684;&#x4EBA;&#x53E3;&#x5728;&#x5C0F;&#x80A0;&#x7684;&#x4FEE;&#x8865;&#x7A0B;&#x5E8F;&#x7684;&#x5F62;&#x6210;&#x4E2D;&#x5177;&#x6709;&#x91CD;&#x8981;&#x4F5C;&#x7528;&#x3002;&#x8FD9;&#x4E9B;&#x5355;&#x5143;&#x683C;&#x7684;&#x4E00;&#x4E2A;&#x5B50;&#x96C6;&#x8868;&#x793A;&#x53D7;&#x4F53;&#x916A;&#x6C28;&#x9178;&#x6FC0;&#x9176; RET&#xFF0C;&#x800C;&#x662F;&#x54FA;&#x4E73;&#x52A8;&#x7269;&#x80A0;&#x795E;&#x7ECF;&#x7CFB;&#x7EDF;&#x5F62;&#x6210;&#x7684;&#x5FC5;&#x8981;&#x6761;&#x4EF6;&#x3002;&#x6211;&#x4EEC;&#x8868;&#x660E; RET &#x4FE1;&#x53F7;&#x4E5F;&#x662F;&#x5C0F;&#x80A0;&#x7684;&#x4FEE;&#x8865;&#x7A0B;&#x5E8F;&#x5F62;&#x6210;&#x7684;&#x5173;&#x952E;&#x3002;&#x529F;&#x80FD;&#x6027;&#x9057;&#x4F20;&#x5206;&#x6790;&#x8868;&#x660E; Gfra3 &#x7F3A;&#x5728;&#x5C0F;&#x80A0;&#x7684;&#x4FEE;&#x8865;&#x7A0B;&#x5E8F;&#x7684;&#x53D1;&#x5C55;&#xFF0C;&#x635F;&#x5BB3;&#x7ED3;&#x679C;&#x8868;&#x660E;&#x4FE1;&#x53F7;&#x8F74; RET/GFRalpha3/ARTN &#x53C2;&#x4E0E;&#x8FD9;&#x4E00;&#x8FDB;&#x7A0B;&#x3002;&#x4E3A;&#x652F;&#x6301;&#x8FD9;&#x4E00;&#x5047;&#x8BBE;&#xFF0C;&#x6211;&#x4EEC;&#x8868;&#x660E; ARTN RET &#x914D;&#x4F53;&#x5F3A;&#x5F15;&#x8BF1;&#x5242;&#x7684;&#x80A0;&#x9053;&#x9020;&#x8840;&#x7EC6;&#x80DE;&#xFF0C;&#x8BF1;&#x5BFC;&#x5F02;&#x4F4D;&#x5C0F;&#x80A0;&#x4FEE;&#x8865;&#x7A0B;&#x5E8F;&#x7C7B;&#x4F3C;&#x7ED3;&#x6784;&#x7684;&#x5F62;&#x6210;&#x3002;&#x6211;&#x4EEC;&#x7684;&#x5DE5;&#x4F5C;&#x5F3A;&#x70C8;&#x8868;&#x660E; RET &#x4FE1;&#x53F7;&#x9014;&#x5F84;&#xFF0C;&#x901A;&#x8FC7;&#x8C03;&#x8282;&#x80A0;&#xFF0C;&#x7D27;&#x5F20;&#x548C;&#x6DCB;&#x5DF4;&#x7CFB;&#x7EDF;&#x7684;&#x5F00;&#x53D1;&#x5173;&#x952E;&#x4F5C;&#x7528;&#x534F;&#x8C03;&#x80A0;&#x5668;&#x5B98;&#x53D1;&#x751F;&#x7684;&#x5206;&#x5B50;&#x673A;&#x5236;&#x3002;

RET &#x916A;&#x6C28;&#x9178;&#x6FC0;&#x9176;&#x53D7;&#x4F53;&#x662F;&#x5C0F;&#x80A0;&#x7684;&#x4FEE;&#x8865;&#x7A0B;&#x5E8F;&#x5668;&#x5B98;&#x53D1;&#x751F;&#x7684;&#x4E00;&#x4E2A;&#x5173;&#x952E;&#x8C03;&#x8282;&#x5668;&#x3002;

Normal organogenesis requires co-ordinate development and interaction of multiple cell types, and is seemingly governed by tissue specific factors. Lymphoid organogenesis during embryonic life is dependent on molecules the temporal expression of which is tightly regulated. During this process, haematopoietic 'inducer' cells interact with stromal 'organizer' cells, giving rise to the lymphoid organ primordia. Here we show that the haematopoietic cells in the gut exhibit a random pattern of motility before aggregation into the primordia of Peyer's patches, a major component of the gut-associated lymphoid tissue. We further show that a CD45+CD4-CD3-Il7Ralpha-c-Kit+CD11c+ haematopoietic population expressing lymphotoxin has an important role in the formation of Peyer's patches. A subset of these cells expresses the receptor tyrosine kinase RET, which is essential for mammalian enteric nervous system formation. We demonstrate that RET signalling is also crucial for Peyer's patch formation. Functional genetic analysis revealed that Gfra3-deficiency results in impairment of Peyer's patch development, suggesting that the signalling axis RET/GFRalpha3/ARTN is involved in this process. To support this hypothesis, we show that the RET ligand ARTN is a strong attractant of gut haematopoietic cells, inducing the formation of ectopic Peyer's patch-like structures. Our work strongly suggests that the RET signalling pathway, by regulating the development of both the nervous and lymphoid system in the gut, has a key role in the molecular mechanisms that orchestrate intestine organogenesis.

Tyrosine kinase receptor RET is a key regulator of Peyer's patch organogenesis.

Organogen&egrave;se normal exige le d&eacute;veloppement coordonnent et l&#39;interaction de plusieurs types de cellules et est apparemment r&eacute;gi par des facteurs sp&eacute;cifiques de tissus. Organogen&egrave;se lympho&iuml;de pendant la vie embryonnaire d&eacute;pend de mol&eacute;cules dont l&#39;expression temporelle est &eacute;troitement contr&ocirc;l&eacute;e. Au cours de ce processus, les cellules h&eacute;matopo&iuml;&eacute;tiques &laquo; inducteur &raquo; interagissent avec cellules stromales &laquo; organisateur &raquo;, donnant lieu aux primordiums des organes lympho&iuml;des. Ici, nous montrons que les cellules h&eacute;matopo&iuml;&eacute;tiques dans la pi&egrave;ce de tube digestif un motif al&eacute;atoire de la motilit&eacute; avant l&#39;agr&eacute;gation dans les primordiums des plaques de Peyer, une composante majeure de la gut-associated lymphoid tissue. Nous montrons &eacute;galement qu&#39;un CD45 + CD4-CD3-Il7Ralpha-c-Kit + CD11c + h&eacute;matopo&iuml;&eacute;tique population exprimant la lymphotoxine a un r&ocirc;le important dans la formation de plaques de Peyer. Un sous-ensemble de ces cellules exprime la tyrosine kinase du r&eacute;cepteur &agrave; la retraite, qui est essentiel pour la formation du syst&egrave;me nerveux ent&eacute;rique des mammif&egrave;res. Nous d&eacute;montrons que RET de signalisation est &eacute;galement crucial pour la formation de zones de Peyer. Functional analyses g&eacute;n&eacute;tiques ont r&eacute;v&eacute;l&eacute; que Gfra3-d&eacute;ficience entra&icirc;ne une insuffisance du d&eacute;veloppement de patch de Peyer, sugg&eacute;rant que l&#39;axe de signalisation RET/GFRalpha3/ARTN est impliqu&eacute; dans ce processus. Pour appuyer cette hypoth&egrave;se, nous montrons que le ligand RET ARTN est un puissant attractant de cellules h&eacute;matopo&iuml;&eacute;tiques de tube digestif, induisant la formation de structures ressemblant &agrave; des patch ectopique de Peyer. Notre travail sugg&egrave;re fortement que la voie de signalisation de RET, en r&eacute;gulant le d&eacute;veloppement du syst&egrave;me nerveux et lympho&iuml;de dans l&#39;intestin, joue un r&ocirc;le cl&eacute; dans les m&eacute;canismes mol&eacute;culaires qui orchestrent l&#39;intestin organogen&egrave;se.

R&eacute;cepteur tyrosine kinase RET est un important r&eacute;gulateur de l&#39;organogen&egrave;se patch de Peyer.

Normale Organogenese erfordert koordinieren Entwicklung und Interaktion mehrerer Zelltypen und Gewebe spezifische Faktoren scheinbar unterliegt. Lymphatischen Organogenese w&auml;hrend des embryonalen Lebens ist abh&auml;ngig von Molek&uuml;len der zeitliche, die Ausdruck davon streng reglementiert ist. W&auml;hrend dieses Vorgangs interagieren h&auml;matopoetische &#39;Induktor&#39; Zellen mit stromal &#39;Organizer&#39; Zellen, was zu den lymphatischen Organ Primordia. Hier zeigen wir, dass die blutbildenden Zellen in den Darm-Ausstellung ein Zufallsmuster von Motilit&auml;t vor der Aggregation in den Primordia Peyer Patches, ein Hauptbestandteil des Darm-assoziierten lymphatischen Gewebes. Wir zeigen, dass weiter eine CD45 + CD4-CD3-Il7Ralpha-c-Kit + CD11c + h&auml;matopoetischen Bev&ouml;lkerung Ausdr&uuml;cken Lymphotoxin spielt eine wichtige Rolle bei der Bildung von Peyer Patches. Eine Teilmenge dieser Zellen dr&uuml;ckt die Rezeptor-Tyrosinkinase RET, die f&uuml;r S&auml;ugetier-Enterischen Nervensystem Bildung erforderlich ist. Wir zeigen, dass RET Signalisierung auch Peyer Patch Bildung von entscheidender Bedeutung ist. Funktionale genetische Analyse ergab, dass Gfra3-Mangel f&uuml;hrt zu Beeintr&auml;chtigung der Peyer Patch-Entwicklung, was darauf hindeutet, dass die Signalisierung Achse RET/GFRalpha3/ARTN an diesem Vorgang beteiligt ist. Um diese Hypothese zu unterst&uuml;tzen, zeigen wir, dass die RET-Ligand ARTN ist eine starke Lockstoff Darm blutbildenden Zellen, induzieren die Bildung von ektopische Peyer Patch-Strukturen. Unsere Arbeit ist ein starker, dass die RET-Signalweg durch &Uuml;berwachung der Entwicklungdes der Nerven- und lymphatischen Systems im Darm, eine Schl&uuml;sselrolle in den molekularen Mechanismen verf&uuml;gt, die Darm Organogenese zu orchestrieren.

Tyrosin Kinase Rezeptor RET ist ein wichtiger Regulator der Peyer Patch Organogenese.

Normale organogenesi richiede di coordinare lo sviluppo e interazione di pi&ugrave; tipi di cellule e apparentemente sono disciplinato da specifici fattori di tessuto. Linfoide organogenesi durante la vita embrionale sono dipendente dalle molecole l&#39;espressione temporale cui &egrave; strettamente regolamentato. Durante questo processo, cellule ematopoietiche &#39;induttore&#39; interagiscono con le cellule stromali &#39;Organizzatore&#39;, dando luogo alla primordia organi linfoidi. Qui ci mostrano che le cellule ematopoietiche in mostra un modello casuale di motilit&agrave; prima aggregazione nella primordia di Peyer, una componente importante del tessuto linfoide associato all&#39;intestino. Abbiamo inoltre mostrano che una CD45 + CD4-CD3-Il7Ralpha-c-Kit + CD11c + ematopoietica popolazione esprimendo lymphotoxin ha un ruolo importante nella formazione di Peyer. Un sottoinsieme di queste cellule esprime il recettore tirosina chinasi RET, che &egrave; essenziale per la formazione del sistema nervoso enterico dei mammiferi. Dimostriamo che segnalazione RET &egrave; anche cruciale per la formazione di zone del Peyer patch. Analisi funzionale genetica ha rivelato che Gfra3-deficit provoca compromissione dello sviluppo di patch di Peyer, suggerendo che l&#39;asse segnalazione RET/GFRalpha3/ARTN &egrave; coinvolto in questo processo. A supporto di questa ipotesi, ci mostra che il ligando RET ARTN &egrave; un forte attrattivo di cellule ematopoietiche gut, che inducono la formazione di strutture simili a patch di Peyer ectopica. Il nostro lavoro suggerisce fortemente che il RET signalling pathway, regolando lo sviluppo del sistema nervoso e linfoide nell&#39;intestino, ha un ruolo chiave nei meccanismi molecolari che orchestrare organogenesi dell&#39;intestino.

Tirosina chinasi recettore RET &egrave; un regolatore chiave dell&#39;organogenesi patch di Peyer.

&#x901A;&#x5E38;&#x306E;&#x5668;&#x5B98;&#x5F62;&#x6210;&#x30B3;&#x30FC;&#x30C7;&#x30A3;&#x30CD;&#x30FC;&#x30C8;&#x958B;&#x767A;&#x3068;&#x8907;&#x6570;&#x306E;&#x7A2E;&#x985E;&#x306E;&#x7D30;&#x80DE;&#x306E;&#x76F8;&#x4E92;&#x4F5C;&#x7528;&#x3092;&#x5FC5;&#x8981;&#x3057;&#x3001;&#x4E00;&#x898B;&#x30C6;&#x30A3;&#x30C3;&#x30B7;&#x30E5;&#x7279;&#x5B9A;&#x306E;&#x8981;&#x56E0;&#x306B;&#x3088;&#x3063;&#x3066;&#x652F;&#x914D;&#x3055;&#x308C;&#x307E;&#x3059;&#x3002;&#x840C;&#x82BD;&#x671F;&#x306E;&#x751F;&#x6D3B;&#x306E;&#x4E2D;&#x306B;&#x30EA;&#x30F3;&#x30D1;&#x7CFB;&#x5668;&#x5B98;&#x5F62;&#x6210;&#x306E;&#x6642;&#x9593;&#x7684;&#x306A;&#x5F0F;&#x304C;&#x5805;&#x304F;&#x8ABF;&#x6574;&#x3055;&#x308C;&#x308B;&#x5206;&#x5B50;&#x306E;&#x4F9D;&#x5B58;&#x3057;&#x3066;&#x3044;&#x307E;&#x3059;&#x3002;&#x3053;&#x306E;&#x30D7;&#x30ED;&#x30BB;&#x30B9;&#x4E2D;&#x306B;&#x306F;&#x3001;&#x9020;&#x8840; &#39;&#x30A4;&#x30F3;&#x30C7;&#x30E5;&#x30FC;&#x30B5;&#39; &#x7D30;&#x80DE;&#x30EA;&#x30F3;&#x30D1;&#x5668;&#x5B98;&#x539F;&#x57FA;&#x306B;&#x4E0A;&#x6607;&#x3092;&#x4E0E;&#x3048;&#x3066;&#x3001;&#x9593;&#x8CEA; &#39;organizer&#39; &#x7D30;&#x80DE;&#x3068;&#x5BFE;&#x8A71;&#x3057;&#x307E;&#x3059;&#x3002;&#x3053;&#x3053;&#x3067;&#x79C1;&#x9054;&#x306F;&#x9020;&#x8840;&#x7D30;&#x80DE;&#x306F;&#x8178;&#x306E;&#x5C55;&#x793A;&#x904B;&#x52D5;&#x306E;&#x539F;&#x57FA;&#x306B;&#x96C6;&#x7D04;&#x8178;&#x7BA1;&#x95A2;&#x9023;&#x30EA;&#x30F3;&#x30D1;&#x7D44;&#x7E54;&#x306E;&#x4E3B;&#x8981;&#x306A;&#x30B3;&#x30F3;&#x30DD;&#x30FC;&#x30CD;&#x30F3;&#x30C8;&#x306E;&#x30D1;&#x30A4;&#x30A8;&#x30EB;&#x677F;&#x524D;&#x306B;&#x3001;&#x306E;&#x30D1;&#x30BF;&#x30FC;&#x30F3;&#x304C;&#x30E9;&#x30F3;&#x30C0;&#x30E0;&#x3067;&#x793A;&#x3057;&#x307E;&#x3059;&#x3002;&#x3055;&#x3089;&#x306B;&#x306F; CD45 + CD4 &#x793A;&#x3059;-CD3-Il7Ralpha-c-&#x30AD;&#x30C3;&#x30C8; + CD11c + &#x9020;&#x8840;&#x30EA;&#x30F3;&#x30DB;&#x30C8;&#x30AD;&#x30B7;&#x30F3;&#x306B;&#x3088;&#x3063;&#x3066;&#x8868;&#x73FE;&#x3059;&#x308B;&#x4EBA;&#x53E3;&#x304C;&#x91CD;&#x8981;&#x306A;&#x5F79;&#x5272;&#x306B;&#x30D1;&#x30A4;&#x30A8;&#x30EB;&#x677F;&#x306E;&#x5F62;&#x6210;&#x3002;&#x3053;&#x308C;&#x3089;&#x306E;&#x7D30;&#x80DE;&#x306E;&#x30B5;&#x30D6;&#x30BB;&#x30C3;&#x30C8;&#x306F;&#x54FA;&#x4E73;&#x985E;&#x306E;&#x8178;&#x795E;&#x7D4C;&#x7CFB;&#x5F62;&#x6210;&#x306B;&#x4E0D;&#x53EF;&#x6B20;&#x3067;&#x3042;&#x308B;&#x53D7;&#x5BB9;&#x4F53;&#x30C1;&#x30ED;&#x30B7;&#x30F3;&#x30AD;&#x30CA;&#x30FC;&#x30BC; RET&#x3001;&#x8868;&#x73FE;&#x3057;&#x3066;&#x3044;&#x307E;&#x3059;&#x3002;&#x6211;&#x3005; &#x306F;&#x3001;RET &#x30B7;&#x30B0;&#x30CA;&#x30EA;&#x30F3;&#x30B0;&#x3082;&#x30D1;&#x30A4;&#x30A8;&#x30EB; &#x30D1;&#x30C3;&#x30C1;&#x5F62;&#x6210;&#x306B;&#x6975;&#x3081;&#x3066;&#x91CD;&#x8981;&#x3067;&#x3042;&#x308B;&#x3053;&#x3068;&#x3092;&#x793A;&#x3057;&#x3066;&#x3044;&#x307E;&#x3059;&#x3002;&#x6A5F;&#x80FD;&#x7684;&#x907A;&#x4F1D;&#x5206;&#x6790; RET/GFRalpha3/ARTN &#x306E;&#x30B7;&#x30B0;&#x30CA;&#x30EB;&#x4F1D;&#x9054;&#x306E;&#x8EF8;&#x306F;&#x3001;&#x3053;&#x306E;&#x30D7;&#x30ED;&#x30BB;&#x30B9;&#x306B;&#x95A2;&#x4E0E;&#x3057;&#x3066;&#x3044;&#x308B;&#x3053;&#x3068;&#x3092;&#x793A;&#x5506; Gfra3 &#x6B20;&#x4E4F;&#x306E;&#x30D1;&#x30A4;&#x30A8;&#x30EB; &#x30D1;&#x30C3;&#x30C1;&#x958B;&#x767A;&#x306E;&#x6E1B;&#x640D;&#x306E;&#x7D50;&#x679C;&#x3092;&#x660E;&#x3089;&#x304B;&#x306B;&#x3057;&#x307E;&#x3057;&#x305F;&#x3002;&#x3053;&#x306E;&#x4EEE;&#x8AAC;&#x3092;&#x30B5;&#x30DD;&#x30FC;&#x30C8;&#x3059;&#x308B;&#x306B;&#x306F;&#x3001;&#x6211;&#x3005; RET &#x30EA;&#x30AC;&#x30F3;&#x30C9; ARTN&#x3001;&#x8178;&#x9020;&#x8840;&#x7D30;&#x80DE;&#x306E;&#x5F37;&#x3044;&#x8A98;&#x5F15;&#x3055;&#x308C;&#x305F;&#x7570;&#x6240;&#x6027;&#x30D1;&#x30A4;&#x30A8;&#x30EB; &#x30D1;&#x30C3;&#x30C1;&#x306E;&#x3088;&#x3046;&#x306A;&#x69CB;&#x9020;&#x306E;&#x5F62;&#x6210;&#x3092;&#x8A98;&#x5C0E;&#x3059;&#x308B;. &#x3057;&#x307E;&#x3059;&#x3002;&#x79C1;&#x305F;&#x3061;&#x306E;&#x4ED5;&#x4E8B;&#x306F;&#x5F37;&#x304F; RET &#x30B7;&#x30B0;&#x30CA;&#x30EA;&#x30F3;&#x30B0;&#x7D4C;&#x8DEF;&#x795E;&#x7D4C;&#x3084;&#x30EA;&#x30F3;&#x30D1; &#x30B7;&#x30B9;&#x30C6;&#x30E0;&#x306F;&#x8178;&#x5185;&#x3067;&#x306E;&#x958B;&#x767A;&#x3092;&#x898F;&#x5236;&#x3059;&#x308B;&#x3053;&#x3068;&#x306B;&#x3088;&#x3063;&#x3066;&#x8178;&#x5668;&#x5B98;&#x306E;&#x5F62;&#x6210;&#x3092;&#x7BA1;&#x5F26;&#x697D;&#x306B;&#x7DE8;&#x66F2;&#x5206;&#x5B50;&#x30E1;&#x30AB;&#x30CB;&#x30BA;&#x30E0;&#x3067;&#x91CD;&#x8981;&#x306A;&#x5F79;&#x5272;&#x3092;&#x6301;&#x3063;&#x3066;&#x3044;&#x308B;&#x3053;&#x3068;&#x3092;&#x793A;&#x5506;&#x3057;&#x307E;&#x3059;&#x3002;

RET &#x30C1;&#x30ED;&#x30B7;&#x30F3;&#x30AD;&#x30CA;&#x30FC;&#x30BC;&#x53D7;&#x5BB9;&#x4F53;&#x306F;&#x3001;&#x30D1;&#x30A4;&#x30A8;&#x30EB; &#x30D1;&#x30C3;&#x30C1;&#x5668;&#x5B98;&#x5F62;&#x6210;&#x306E;&#x4E3B;&#x30EC;&#x30AE;&#x30E5;&#x30EC;&#x30FC;&#x30BF;&#x3067;&#x3059;&#x3002;

&#xC77C;&#xBC18; organogenesis &#xACF5;&#xB3D9; &#xAC1C;&#xBC1C; &#xBC0F; &#xC0C1;&#xD638; &#xC791;&#xC6A9;&#xC758; &#xC5EC;&#xB7EC; &#xC138;&#xD3EC; &#xC720;&#xD615;, &#xD544;&#xC694; &#xAC89;&#xBCF4;&#xAE30; &#xC870;&#xC9C1;&#xC758; &#xD2B9;&#xC815; &#xC694;&#xC778;&#xC5D0; &#xC758;&#xD574; &#xC11C; &#xC6B4;&#xC601; &#xB418; &#xACE0;. &#xBC30;&#xC544; &#xC0DD;&#xD65C; &#xB3D9;&#xC548; &#xB9BC;&#xD504; organogenesis &#xBD84;&#xC790;&#xB294; &#xC2DC;&#xAC04;&#xC801; &#xC2DD; &#xB2E8;&#xB2E8;&#xD788; &#xD1B5;&#xC81C;&#xC5D0; &#xB530;&#xB77C; &#xB2EC;&#xB77C; &#xC9D1;&#xB2C8;&#xB2E4;. &#xC774; &#xACFC;&#xC815; haematopoietic &#39;&#xC720;&#xB3C4;&#39; &#xC140; &#xB9BC;&#xD504; &#xAE30;&#xAD00; primordia&#xB97C; &#xC57C; &#xAE30;&#xD55C; &#39;&#xC8FC;&#xCD5C;&#xC790;&#39; stromal &#xC138;&#xD3EC;&#xC640; &#xC0C1;&#xD638; &#xC791;&#xC6A9; &#xD569;&#xB2C8;&#xB2E4;. &#xC5EC;&#xAE30; &#xC6B0;&#xB9AC;&#xAC00; &#xD45C;&#xC2DC; &#xD558;&#xB294; haematopoietic &#xC140; &#xC6A9;&#xAE30; &#xC804;&#xC2DC; &#xC9D1;&#xACC4;&#xB97C; primordia&#xC5D0; Peyer&#xC758; &#xD328;&#xCE58;, &#xCC3D; &#xC790; &#xC5F0;&#xAD00; &#xB41C; &#xB9BC;&#xD504; &#xC870;&#xC9C1;&#xC758; &#xC8FC;&#xC694; &#xAD6C;&#xC131; &#xC694;&#xC18C; &#xC804;&#xC5D0; &#xC6B4;&#xB3D9; &#xC131;&#xC758; &#xC784;&#xC758;&#xC758; &#xD328;&#xD134;&#xC5D0;. &#xC6B0;&#xB9AC; &#xB354; CD45 + CD4 &#xBCF4;&#xC5EC;-CD3-Il7Ralpha-c-&#xD0A4;&#xD2B8; + CD11c + haematopoietic lymphotoxin&#xC744; &#xD45C;&#xD604; &#xD558;&#xB294; &#xC778;&#xAD6C; Peyer&#xC758; &#xD328;&#xCE58;&#xC758; &#xD615;&#xC131;&#xC5D0; &#xC911;&#xC694; &#xD55C; &#xC5ED;&#xD560;&#xC744; &#xD588;&#xB2E4;. &#xC774;&#xB7EC;&#xD55C; &#xC140;&#xC758; &#xD558;&#xC704; &#xC9D1;&#xD569;&#xC5D0;&#xB294; &#xD3EC;&#xC720;&#xB958; &#xC7A5;&#xC758; &#xC2E0; &#xACBD;&#xACC4; &#xD615;&#xC131;&#xC5D0; &#xD544;&#xC218;&#xC801;&#xC778; &#xC218;&#xC6A9; &#xCCB4; &#xD2F0;&#xB85C;&#xC2E0; &#xD0A4; &#xB2C8; &#xC544; &#xC81C; RET, &#xD45C;&#xD604;. RET &#xC2E0;&#xD638;&#xB294; &#xB610;&#xD55C; Peyer&#xC758; &#xD328;&#xCE58; &#xD615;&#xC131;&#xC744; &#xC704;&#xD55C; &#xC911;&#xC694; &#xD55C; &#xBCF4;&#xC5EC; &#xC90D;&#xB2C8;&#xB2E4;. &#xAE30;&#xB2A5;&#xC131; &#xC720;&#xC804;&#xC790; &#xBD84;&#xC11D; Gfra3 &#xACB0;&#xD54D; &#xC2E0;&#xD638; &#xCD95; RET/GFRalpha3/ARTN&#xC774;&#xC774; &#xACFC;&#xC815;&#xC5D0; &#xCC38;&#xC5EC; &#xC81C;&#xC548; Peyer&#xC758; &#xD328;&#xCE58; &#xAC1C;&#xBC1C;&#xC758; &#xC7A5;&#xC560;&#xAC00; &#xACB0;&#xACFC; &#xACF5;&#xAC1C;. &#xC774; &#xAC00;&#xC124;&#xC744; &#xC9C0;&#xC6D0; &#xD558;&#xAE30; &#xC704;&#xD574; &#xC6B0;&#xB9AC;&#xAC00; &#xBCF4;&#xC5EC; RET &#xB9AC;&#xAC04;&#xB4DC; ARTN &#xC6A9;&#xAE30; haematopoietic &#xC140;&#xC758; &#xAC15;&#xD55C; &#xC720;&#xC778;&#xC740; &#xC18C;&#xC131; Peyer&#xC758; &#xD328;&#xCE58; &#xBAA8;&#xC591;&#xC758; &#xAD6C;&#xC870; &#xD615;&#xC131; &#xC720;&#xB3C4;. &#xC6B0;&#xB9AC;&#xC758; &#xC791;&#xC5C5;&#xC744; &#xAC15;&#xB825; &#xD558; &#xAC8C; RET &#xC2E0;&#xD638; &#xD1B5;&#xB85C; &#xC6A9;&#xAE30;, &#xAE34;&#xC7A5; &#xBC0F; &#xB9BC;&#xD504; &#xC2DC;&#xC2A4;&#xD15C;&#xC758; &#xAC1C;&#xBC1C;&#xC744; &#xADDC;&#xC81C; &#xD558; &#xC5EC; &#xC911;&#xC694; &#xD55C; &#xC5ED;&#xD560;&#xC5D0;&#xC5D0;&#xC11C; &#xC788;&#xB294; &#xC18C;&#xC7A5; organogenesis &#xC870;&#xC815; &#xD558;&#xB294; &#xBD84;&#xC790; &#xBA54;&#xCEE4;&#xB2C8;&#xC998; &#xC81C;&#xC548; &#xD569;&#xB2C8;&#xB2E4;.

&#xD2F0;&#xB85C;&#xC2E0; &#xD0A4; &#xB2C8; &#xC544; &#xC81C; &#xC218;&#xC6A9; &#xCCB4; RET Peyer&#xC758; &#xD328;&#xCE58; organogenesis&#xC758; &#xD0A4; &#xB808; &#xADE4; &#xB808;&#xC774; &#xD130; &#xC774;&#xB2E4;.

Organog&eacute;nesis normal requiere desarrollo coordinado y la interacci&oacute;n de m&uacute;ltiples tipos de c&eacute;lulas y aparentemente se rigen por factores espec&iacute;ficos de tejido. Organog&eacute;nesis linfoide durante la vida embrionaria depende de mol&eacute;culas la expresi&oacute;n temporal que es estrictamente regulada. Durante este proceso, hematopoy&eacute;ticas &#39;inductor&#39; c&eacute;lulas interact&uacute;an con las c&eacute;lulas stromal &#39;organizador&#39;, dando lugar a los primordios de &oacute;rgano linfoide. Aqu&iacute; se muestran que las c&eacute;lulas hematopoy&eacute;ticas en la exposici&oacute;n de la tripa un patr&oacute;n aleatorio de motilidad antes de agregaci&oacute;n en los primordios de placas de Peyer, un componente importante del tejido linfoide asociado a intestino. M&aacute;s que mostramos un CD45 + CD4-CD3-Il7Ralpha-c-Kit + CD11c + hematopoy&eacute;ticas poblaci&oacute;n expresando linfotoxina tiene un papel importante en la formaci&oacute;n de placas de Peyer. Un subconjunto de estas c&eacute;lulas expresa el receptor tirosina quinasa RET, que es esencial para la formaci&oacute;n del sistema nervioso ent&eacute;rico mam&iacute;fero. Demostramos que la se&ntilde;alizaci&oacute;n de RET tambi&eacute;n es crucial para la formaci&oacute;n de parches de Peyer. El an&aacute;lisis gen&eacute;tico funcional revel&oacute; que Gfra3-deficiencia resulta en el deterioro del desarrollo de parches de Peyer, sugiriendo que el eje de se&ntilde;alizaci&oacute;n RET/GFRalpha3/ARTN est&aacute; implicado en este proceso. Para apoyar esta hip&oacute;tesis, demostramos que el ligando RET ARTN es un fuerte atrayente de c&eacute;lulas hematopoy&eacute;ticas de tripa, induciendo la formaci&oacute;n de estructuras parches de Peyer ect&oacute;pico. Nuestro trabajo sugiere que la v&iacute;a de se&ntilde;alizaci&oacute;n de RET, regulando el desarrollo del sistema nervioso y linfoide en el intestino, tiene un papel clave en los mecanismos moleculares que orquestan la organog&eacute;nesis del intestino.

Receptor de la tirosina cinasa RET es un regulador clave de la organog&eacute;nesis de parches de Peyer.

Neural crest (NC)-derived mesenchyme has previously been shown to play an important role in the development of fetal thymus. Using Wnt1-Cre and Sox10-Cre mice crossed to Rosa26(eYfp) reporter mice, we have revealed NC-derived mesenchymal cells in the adult murine thymus. We report that NC-derived cells infiltrate the thymus before day 13.5 of embryonic development (E13.5) and differentiate into cells with characteristics of smooth muscle cells associated with large vessels, and pericytes associated with capillaries. In the adult organ at 3 mo of age, these NC-derived perivascular cells continue to be associated with the vasculature, providing structural support to the blood vessels and possibly regulating endothelial cell function.

Contribution of neural crest-derived cells in the embryonic and adult thymus.

This chapter provides information on imaging tools that can be employed to visualise and study lymphoid organ development. We focus on the use of genetically modified mouse models that take advantage of fluorescent protein expression in discrete cell populations, thus allowing live cell imaging during lymphoid organogenesis. We discuss approaches that allow characterisation of the cell types involved in the formation of lymphoid organs, including (i) functional assays in explant organ cultures and (ii) high-resolution whole-mount immunostaining methods, which are useful for the characterisation of specific cell populations in the context of the whole developing organ.

Visualisation of lymphoid organ development.

Nuclear architecture and chromatin reorganization have recently been shown to orchestrate gene expression and act as key players in developmental pathways. To investigate how regulatory elements in the mouse CD8 gene locus are arranged in space and in relation to each other, three-dimensional fluorescence in situ hybridization and chromosome conformation capture techniques were employed to monitor the repositioning of the locus in relation to its subchromosomal territory and to identify long-range interactions between the different elements during development. Our data demonstrate that CD8 gene expression in murine lymphocytes is accompanied by the relocation of the locus outside its subchromosomal territory. Similar observations in the CD4 locus point to a rather general phenomenon during T cell development. Furthermore, we show that this relocation of the CD8 gene locus is associated with a clustering of regulatory elements forming a tight active chromatin hub in CD8-expressing cells. In contrast, in nonexpressing cells, the gene remains close to the main body of its chromosomal domain and the regulatory elements appear not to interact with each other.

CD8 locus nuclear dynamics during thymocyte development.

Thymus Organogenese erfordert koordinierte Interaktionen mehrerer Zelltypen, einschlie&szlig;lich Neuralleistenzellen (NC), die Formation, Trennung und anschlie&szlig;ende Migration der entwickelnden Thymus aus der dritten Pharynx Beutel in der Brusth&ouml;hle zu orchestrieren. Die molekularen Mechanismen, die diese Prozesse fahren sind unklar; NC-abgeleitete Mesenchym hat jedoch gezeigt wurde, eine wichtige Rolle spielen. Hier zeigen wir, dass in Ermangelung Ephrin-B2-Ausdruck auf Thymom NC abgeleitete Mesenchym, Thymus im zervikalen Bereich statt Migration in die Brusth&ouml;hle bleibt. Analyse einzelner NC-abgeleitete Thymom Mesenchymale Zellen zeigt, dass in Ermangelung Ephrin-B2, ihre Motilit&auml;t aufgrund defekter EphB Rezeptor Signalgebung beeintr&auml;chtigt wird. Dies impliziert eine NC-abgeleitete zellspezifische Rolle EphB-Ephrin-B2-Interaktionen bei der kollektiven Migration von Thymom Rudiment w&auml;hrend der Organogenese.

EphB-Ephrin-B2-Interaktionen sind f&uuml;r Thymus Migration w&auml;hrend der Organogenese erforderlich.

&#x80F8;&#x817A;&#x5668;&#x5B98;&#x53D1;&#x751F;&#x9700;&#x8981;&#x534F;&#x8C03;&#x4E00;&#x81F4;&#x7684;&#x591A;&#x4E2A;&#x5355;&#x5143;&#x683C;&#x7C7B;&#x578B;&#xFF0C;&#x5176;&#x4E2D;&#x5305;&#x62EC;&#x795E;&#x7ECF;&#x5D74; &#xFF08;NC&#xFF09; &#x7684;&#x5355;&#x5143;&#x683C;&#xFF0C;&#x4EE5;&#x534F;&#x8C03;&#x5F62;&#x6210;&#x3001; &#x5206;&#x79BB;&#x548C;&#x968F;&#x540E;&#x8FC1;&#x79FB;&#x5230;&#x8154;&#x5185;&#x7B2C;&#x4E09;&#x6B21;&#x54BD;&#x90AE;&#x888B;&#x4ECE;&#x53D1;&#x5C55;&#x4E2D;&#x56FD;&#x5BB6;&#x80F8;&#x817A;&#x7684;&#x76F8;&#x4E92;&#x4F5C;&#x7528;&#x3002;&#x9A7E;&#x9A76;&#x8FD9;&#x4E9B;&#x8FDB;&#x7A0B;&#x7684;&#x5206;&#x5B50;&#x673A;&#x5236;&#x5C1A;&#x4E0D;&#x6E05;&#x695A; &#xFF1B;&#x7136;&#x800C;&#xFF0C;NC &#x6E90;&#x6027;&#x95F4;&#x5145;&#x8D28;&#x8868;&#x660E;&#x8981;&#x53D1;&#x6325;&#x91CD;&#x8981;&#x7684;&#x4F5C;&#x7528;&#x3002;&#x5728;&#x8FD9;&#x91CC;&#xFF0C;&#x6211;&#x4EEC;&#x8868;&#x660E;&#xFF0C;ephrin B2 &#x8868;&#x8FBE;&#x5BF9;&#x80F8;&#x817A;&#x6570;&#x63A7;&#x6E90;&#x6027;&#x95F4;&#x5145;&#x8D28;&#x7684;&#x7F3A;&#x5E2D;&#xFF0C;&#x80F8;&#x817A;&#x4ECD;&#x7136;&#x5728;&#x9888;&#x690E;&#x9886;&#x57DF;&#x800C;&#x4E0D;&#x662F;&#x8FC1;&#x79FB;&#x5230;&#x80F8;&#x8154;&#x3002;&#x4E2A;&#x522B;&#x6570;&#x63A7;&#x80F8;&#x817A;&#x95F4;&#x5145;&#x8D28;&#x7EC6;&#x80DE;&#x7684;&#x5206;&#x6790;&#x8868;&#x660E; ephrin B2 &#x7F3A;&#x4E4F;&#xFF0C;&#x5176;&#x52A8;&#x529B;&#x662F;&#xFF0C;&#x7531;&#x4E8E;&#x6709;&#x7F3A;&#x9677;&#x7684; EphB &#x53D7;&#x4F53;&#x4FE1;&#x53F7;&#x53D7;&#x635F;&#x3002;&#x8FD9;&#x610F;&#x5473;&#x7740;&#x5728;&#x80F8;&#x817A;&#x7684;&#x840C;&#x82BD;&#x65F6;&#x671F;&#x5668;&#x5B98;&#x53D1;&#x751F;&#x96C6;&#x4F53;&#x8FC1;&#x79FB; EphB-ephrin-B2 &#x76F8;&#x4E92;&#x4F5C;&#x7528;&#x7684; NC &#x6D3E;&#x751F;&#x7279;&#x5B9A;&#x5355;&#x5143;&#x683C;&#x7684;&#x4F5C;&#x7528;&#x3002;

EphB-ephrin-B2 &#x4EA4;&#x4E92;&#x90FD;&#x9700;&#x8981;&#x80F8;&#x817A;&#x5668;&#x5B98;&#x53D1;&#x751F;&#x8FC7;&#x7A0B;&#x7684;&#x8FC1;&#x79FB;&#x3002;

Thymus organogenesis requires coordinated interactions of multiple cell types, including neural crest (NC) cells, to orchestrate the formation, separation, and subsequent migration of the developing thymus from the third pharyngeal pouch to the thoracic cavity. The molecular mechanisms driving these processes are unclear; however, NC-derived mesenchyme has been shown to play an important role. Here, we show that, in the absence of ephrin-B2 expression on thymic NC-derived mesenchyme, the thymus remains in the cervical area instead of migrating into the thoracic cavity. Analysis of individual NC-derived thymic mesenchymal cells shows that, in the absence of ephrin-B2, their motility is impaired as a result of defective EphB receptor signaling. This implies a NC-derived cell-specific role of EphB-ephrin-B2 interactions in the collective migration of the thymic rudiment during organogenesis.

EphB-ephrin-B2 interactions are required for thymus migration during organogenesis.

Organogen&#xE8;se Thymus n&#xE9;cessite des interactions coordonn&#xE9;es de plusieurs types cellulaires, y compris de la cr&#xEA;te neurale (NC) des cellules, pour orchestrer la formation, la s&#xE9;paration, et la migration ult&#xE9;rieure du thymus en d&#xE9;veloppement de la troisi&#xE8;me poche pharyngienne &#xE0; la cavit&#xE9; thoracique. Les m&#xE9;canismes mol&#xE9;culaires de conduite de ces processus ne sont pas claires, mais, NC-d&#xE9;riv&#xE9;e m&#xE9;senchyme a &#xE9;t&#xE9; montr&#xE9; &#xE0; jouer un r&#xF4;le important. Ici, nous montrons que, en l&#x26;#39;absence d&#x26;#39;&#xE9;phrine-B2 expression thymique NC-d&#xE9;riv&#xE9;e m&#xE9;senchyme, le thymus reste dans la zone cervicale au lieu de migrer dans la cavit&#xE9; thoracique. Analyse des diff&#xE9;rents d&#xE9;riv&#xE9;s NC-thymiques montre que des cellules m&#xE9;senchymateuses, en l&#x26;#39;absence d&#x26;#39;&#xE9;phrine-B2, leur motilit&#xE9; est alt&#xE9;r&#xE9;e en raison d&#x26;#39;un d&#xE9;faut de r&#xE9;cepteur EphB de signalisation. Cela implique une NC-d&#xE9;riv&#xE9; sp&#xE9;cifique des cellules r&#xF4;le de EphB-&#xE9;phrine-B2 interactions dans la migration collective de l&#x26;#39;&#xE9;bauche thymique cours de l&#x26;#39;organogen&#xE8;se.

EphB-&#xE9;phrine-B2 interactions sont n&#xE9;cessaires &#xE0; la migration du thymus durant l&#x26;#39;organogen&#xE8;se

Organogenesi Timo richiede interazioni coordinate di pi&ugrave; tipi di cellule, tra cui cellule della cresta neurale (NC), per orchestrare la formazione, la separazione e la conseguente migrazione del timo in via di sviluppo dalla terza tasca faringea alla cavit&agrave; toracica. I meccanismi molecolari alla guida di questi processi non sono chiari; Tuttavia, mesenchima derivato da NC ha dimostrato di giocare un ruolo importante. Qui, ci mostra che, in assenza di espressione efrina-B2 su mesenchima derivato da NC del timo, timo rimane nell&#39;area cervicale invece di migrare nella cavit&agrave; toracica. Analisi delle singole cellule mesenchimali del timo NC-derivato dimostra che, in assenza di efrina-B2, la loro motilit&agrave; &egrave; alterata a seguito di segnalazione del ricevitore EphB difettoso. Questo implica un ruolo specifico delle cellule NC-derivato di interazioni EphB-efrina-B2 nella migrazione collettiva del rudimento timico durante l&#39;organogenesi.

EphB-efrina-B2 interazioni sono necessarie per la migrazione di Timo durante l&#39;organogenesi.

&#x80F8;&#x817A;&#x5668;&#x5B98;&#x306F;&#x795E;&#x7D4C;&#x5824;&#xFF08;NC&#xFF09;&#x7D30;&#x80DE;&#x3092;&#x542B;&#x3080;&#x8907;&#x6570;&#x306E;&#x7D30;&#x80DE;&#x578B;&#x3001;&#x306E;&#x5354;&#x8ABF;&#x76F8;&#x4E92;&#x4F5C;&#x7528;&#x304C;&#x5F62;&#x6210;&#x3001;&#x5206;&#x96E2;&#x3001;&#x304A;&#x3088;&#x3073;&#x80F8;&#x8154;&#x306E;&#x4E09;&#x756A;&#x76EE;&#x306E;&#x54BD;&#x982D;&#x56A2;&#x304B;&#x3089;&#x958B;&#x767A;&#x80F8;&#x817A;&#x306E;&#x5F8C;&#x7D9A;&#x306E;&#x79FB;&#x884C;&#x3092;&#x8ABF;&#x6574;&#x3059;&#x308B;&#x5FC5;&#x8981;&#x304C;&#x3042;&#x308A;&#x307E;&#x3059;&#x3002;&#x3053;&#x308C;&#x3089;&#x306E;&#x30D7;&#x30ED;&#x30BB;&#x30B9;&#x3092;&#x99C6;&#x52D5;&#x3059;&#x308B;&#x5206;&#x5B50;&#x30E1;&#x30AB;&#x30CB;&#x30BA;&#x30E0;&#x306F;&#x4E0D;&#x660E;&#x3067;&#x3042;&#x308B;&#x304C;&#x3001;NC-&#x7531;&#x6765;&#x306E;&#x9593;&#x8449;&#x306F;&#x91CD;&#x8981;&#x306A;&#x5F79;&#x5272;&#x3092;&#x679C;&#x305F;&#x3059;&#x3053;&#x3068;&#x304C;&#x793A;&#x3055;&#x308C;&#x3066;&#x3044;&#x308B;&#x3002;&#x3053;&#x3053;&#x3067;&#x306F;&#x3001;&#x80F8;&#x817A;NC&#x7531;&#x6765;&#x306E;&#x9593;&#x8449;&#x306B;&#x30A8;&#x30D5;&#x30EA;&#x30F3;-B2&#x767A;&#x73FE;&#x306E;&#x6709;&#x7121;&#x3067;&#x306F;&#x3001;&#x80F8;&#x817A;&#x3067;&#x306F;&#x306A;&#x304F;&#x3001;&#x80F8;&#x8154;&#x5185;&#x306B;&#x79FB;&#x884C;&#x3059;&#x308B;&#x305F;&#x3081;&#x306E;&#x9838;&#x90E8;&#x306B;&#x6B8B;&#x3063;&#x3066;&#x3044;&#x308B;&#x3001;&#x3053;&#x3068;&#x3092;&#x793A;&#x3057;&#x3066;&#x3044;&#x308B;&#x3002; &#x3001;&#x30A8;&#x30D5;&#x30EA;&#x30F3;-B2&#x306E;&#x4E0D;&#x5728;&#x4E0B;&#x3067;&#x3001;&#x305D;&#x306E;&#x904B;&#x52D5;&#x304C;&#x30B7;&#x30B0;&#x30CA;&#x30EA;&#x30F3;&#x30B0;&#x306E;&#x6B20;&#x9665;EphB&#x53D7;&#x5BB9;&#x4F53;&#x306E;&#x7D50;&#x679C;&#x3068;&#x3057;&#x3066;&#x640D;&#x306A;&#x308F;&#x308C;&#x3066;&#x3044;&#x308B;&#x500B;&#x3005;&#x306E;NC-&#x7531;&#x6765;&#x306E;&#x80F8;&#x817A;&#x9593;&#x8449;&#x7CFB;&#x7D30;&#x80DE;&#x756A;&#x7D44;&#x306E;&#x5206;&#x6790;&#x3002;&#x3053;&#x308C;&#x306F;&#x5668;&#x5B98;&#x5F62;&#x6210;&#x671F;&#x80F8;&#x817A;&#x539F;&#x57FA;&#x306E;&#x96C6;&#x5408;&#x79FB;&#x884C;&#x306E;EphB-&#x30A8;&#x30D5;&#x30EA;&#x30F3;-B2&#x306E;&#x76F8;&#x4E92;&#x4F5C;&#x7528;&#x306E;NC-&#x7531;&#x6765;&#x306E;&#x7D30;&#x80DE;&#x7279;&#x7570;&#x7684;&#x306A;&#x5F79;&#x5272;&#x3092;&#x610F;&#x5473;&#x3057;&#x307E;&#x3059;&#x3002;

EphB-&#x30A8;&#x30D5;&#x30EA;&#x30F3;-B2&#x76F8;&#x4E92;&#x4F5C;&#x7528;&#x306F;&#x5668;&#x5B98;&#x5F62;&#x6210;&#x671F;&#x80F8;&#x817A;&#x79FB;&#x884C;&#x306B;&#x5FC5;&#x8981;&#x306A;

Thymus organogenesis &#xC5EC;&#xB7EC; &#xC885;&#xB958;&#xC758; &#xC138;&#xD3EC;, &#xC2E0;&#xACBD;&#xB3C4;&#xAC00; &#xBA38;&#xB9AC; (NC) &#xC140;&#xC744; &#xD3EC;&#xD568; &#xD558; &#xC5EC; &#xCDE8;&#xD560; &#xD615;&#xC131;, &#xBD84;&#xB9AC;, &#xADF8;&#xB9AC;&#xACE0; &#xD749; &#xAC15;&#xC5D0; &#xC138; &#xBC88;&#xC9F8; pharyngeal &#xC8FC;&#xBA38;&#xB2C8;&#xC5D0;&#xC11C; &#xAC1C;&#xBC1C; thymus&#xC758; &#xD6C4;&#xC18D; &#xB9C8;&#xC774;&#xADF8;&#xB808;&#xC774;&#xC158; &#xC870;&#xC815;&#xB41C; &#xC0C1;&#xD638; &#xC791;&#xC6A9; &#xD574;&#xC57C; &#xD569;&#xB2C8;&#xB2E4;. &#xC774;&#xB7EC;&#xD55C; &#xD504;&#xB85C;&#xC138;&#xC2A4;&#xB97C; &#xAD6C;&#xB3D9; &#xD558;&#xB294; &#xBD84;&#xC790; &#xBA54;&#xCEE4;&#xB2C8;&#xC998;&#xC740; &#xBD84;&#xBA85;; &#xADF8;&#xB7EC;&#xB098;, &#xB178;&#xC2A4;&#xCE90;&#xB864;&#xB77C;&#xC774;&#xB098; &#xD30C;&#xC0DD; &#xB41C; mesenchyme &#xC911;&#xC694; &#xD55C; &#xC5ED;&#xD560;&#xC744; &#xBCF4;&#xC5EC;&#xC918; &#xC654;&#xB2E4;. &#xC5EC;&#xAE30;, &#xC6B0;&#xB9AC;&#xAC00;, thymic NC &#xD30C;&#xC0DD; &#xB41C; mesenchyme&#xC5D0; ephrin B2 &#xC2DD;&#xC758; &#xBD80;&#xC7AC;, thymus &#xD749; &#xAC15;&#xC5D0; &#xB9C8;&#xC774;&#xADF8;&#xB808;&#xC774;&#xC158;&#xD558;&#xB294; &#xB300;&#xC2E0; &#xC790; &#xAD81; &#xACBD;&#xBD80; &#xC9C0;&#xC5ED;&#xC5D0; &#xB0A8;&#xC544; &#xC1FC;. &#xAC1C;&#xBCC4; NC &#xD30C;&#xC0DD; thymic &#xC911;&#xAC04; &#xC5FD; &#xC138;&#xD3EC; &#xBD84;&#xC11D; ephrin b2&#xC758; &#xBD80;&#xC7AC;, &#xADF8;&#xB4E4;&#xC758; &#xC6B4;&#xB3D9; &#xC131;, &#xACB0;&#xD568;&#xC774; &#xC788;&#xB294; EphB &#xC218;&#xC6A9; &#xCCB4; &#xC2E0;&#xD638; &#xACB0;&#xACFC;&#xB85C; &#xC7A5;&#xC560;&#xC778;&#xC740; &#xBCF4;&#xC5EC; &#xC90D;&#xB2C8;&#xB2E4;. Organogenesis &#xC911; &#xC9D1;&#xB2E8; &#xB9C8;&#xC774;&#xADF8;&#xB808;&#xC774;&#xC158;&#xC758; thymic rudiment EphB ephrin B2 &#xC0C1;&#xD638; &#xC791;&#xC6A9;&#xC758; NC &#xD30C;&#xC0DD; &#xC140; &#xD2B9;&#xC815; &#xC5ED;&#xD560;&#xC744; &#xC758;&#xBBF8;&#xD569;&#xB2C8;&#xB2E4;.

EphB ephrin B2 &#xC0C1;&#xD638; &#xC791;&#xC6A9; organogenesis &#xB3D9;&#xC548; thymus &#xB9C8;&#xC774;&#xADF8;&#xB808;&#xC774;&#xC158; &#xD544;&#xC694; &#xD558;&#xB2E4;.

Organog&#xE9;nesis del timo requiere la interacci&#xF3;n coordinada de m&#xFA;ltiples tipos de c&#xE9;lulas, incluidas las de la cresta neural (NC), las c&#xE9;lulas, para organizar la formaci&#xF3;n, la separaci&#xF3;n, y la consiguiente migraci&#xF3;n del timo en desarrollo de la bolsa far&#xED;ngea tercio de la cavidad tor&#xE1;cica. Los mecanismos moleculares de conducci&#xF3;n de estos procesos no son claros, sin embargo, NC-derivado mes&#xE9;nquima se ha demostrado que desempe&#xF1;an un papel importante. Aqu&#xED;, nos muestran que, en ausencia de ephrin-B2 expresi&#xF3;n t&#xED;mica NC-mes&#xE9;nquima derivado, el timo se mantiene en la zona cervical en lugar de migrar hacia la cavidad tor&#xE1;cica. An&#xE1;lisis de individuales NC-derivados muestra t&#xED;micos mesenquimales c&#xE9;lulas que, en ausencia de ephrin-B2, se altera su motilidad como un resultado de defectos del receptor EphB se&#xF1;alizaci&#xF3;n. Esto implica un NC-derivado de c&#xE9;lulas espec&#xED;ficas de papel de EphB-ephrin-B2 interacciones en la migraci&#xF3;n colectiva de los rudimentos del timo durante la organog&#xE9;nesis.

EphB ephrin-B2-Las interacciones son necesarias para la migraci&#xF3;n del timo durante la organog&#xE9;nesis

During the early development of the gastrointestinal tract, signaling through the receptor tyrosine kinase RET is required for initiation of lymphoid organ (Peyer's patch) formation and for intestinal innervation by enteric neurons. RET signaling occurs through glial cell line-derived neurotrophic factor (GDNF) family receptor α co-receptors present in the same cell (signaling in cis). It is unclear whether RET signaling in trans, which occurs in vitro through co-receptors from other cells, has a biological role. We showed that the initial aggregation of hematopoietic cells to form lymphoid clusters occurred in a RET-dependent, chemokine-independent manner through adhesion-mediated arrest of lymphoid tissue initiator (LTin) cells. Lymphoid tissue inducer cells were not necessary for this initiation phase. LTin cells responded to all RET ligands in trans, requiring factors from other cells, whereas RET was activated in enteric neurons exclusively by GDNF in cis. Furthermore, genetic and molecular approaches revealed that the versatile RET responses in LTin cells were determined by distinct patterns of expression of the genes encoding RET and its co-receptors. Our study shows that a trans RET response in LTin cells determines the initial phase of enteric lymphoid organ morphogenesis, and suggests that differential co-expression of Ret and Gfra can control the specificity of RET signaling.

Differential RET signaling pathways drive development of the enteric lymphoid and nervous systems.

Intravital microscopy of the calvarium is the only noninvasive method for high-resolution imaging of the bone marrow (BM) and hematopoietic stem cell (HSC) niches. However, it is unclear if the calvarium is representative of all BM compartments. Using the combination of whole body optical imaging, intravital microscopy, and "in vivo fluorescence trapping," a thorough comparison of HSCs and putative HSC niches in the calvaria, epiphyses, and diaphyses, at steady state or after HSC transplantation, can be made. We report substantial heterogeneity between different BM compartments in terms of bone-remodeling activity (BRA), blood volume fraction (BVF), and hypoxia. Although BVF is high in all BM compartments, including areas adjacent to the endosteum, we found that compartments displaying the highest BVF and BRA were preferentially seeded and engrafted upon HSC transplantation. Unexpectedly, the macroanatomical distribution of HSCs at steady state is homogeneous across these 3 areas and independent of these 2 parameters and suggests the existence of "reconstituting niches," which are distinct from "homeostatic niches." Both types of niches were observed in the calvarium, indicating that endochondral ossification, the process needed for the formation of HSC niches during embryogenesis, is dispensable for the formation of HSC niches during adulthood.

Multimodal imaging reveals structural and functional heterogeneity in different bone marrow compartments: functional implications on hematopoietic stem cells.

In addition to well-characterized CD34(+) hematopoietic stem and progenitor cells (HSPCs), the human hematopoietic stem cell (HSC) hierarchy contains a rare CD34(-) population with severe combined immunodeficiency-repopulating capacity. However, little is known about the molecular characteristics of these CD34(-) cells or their relationship to the CD34(+) populations. Here, we show that the self-renewing Lin(-)CD34(-)CD38(-)CD93(hi) population contains cells that not only function as HSCs, but can also be placed above the CD34(+) populations in the hematopoietic hierarchy. These cells have an active Notch pathway, in which signaling through Delta4 is crucial for maintenance of the primitive state, and combined signals from Jagged1 and TGF-β are important in controlling its quiescence. They are also refractory to proliferative signals and show a repressed canonical Wnt pathway, in part regulated by Notch. Overall, therefore, CD34(-) cells represent an immature and quiescent human HSC population maintained through a distinctive network of cellular signaling interactions.

CD34(-) cells at the apex of the human hematopoietic stem cell hierarchy have distinctive cellular and molecular signatures.

Hematopoietic stem and progenitor cells (HSPCs) are exposed to low levels of oxygen in the bone marrow niche, and hypoxia-inducible factors (HIFs) are the main regulators of cellular responses to oxygen variation. Recent studies using conditional knockout mouse models have unveiled a major role for HIF-1α in the maintenance of murine HSCs; however, the role of HIF-2α is still unclear. Here, we show that knockdown of HIF-2α, and to a much lesser extent HIF-1α, impedes the long-term repopulating ability of human CD34(+) umbilical cord blood cells. HIF-2α-deficient HSPCs display increased production of reactive oxygen species (ROS), which subsequently stimulates endoplasmic reticulum (ER) stress and triggers apoptosis by activation of the unfolded-protein-response (UPR) pathway. HIF-2α deregulation also significantly decreased engraftment ability of human acute myeloid leukemia (AML) cells. Overall, our data demonstrate a key role for HIF-2α in the maintenance of human HSPCs and in the survival of primary AML cells.

HIF-2α protects human hematopoietic stem/progenitors and acute myeloid leukemic cells from apoptosis induced by endoplasmic reticulum stress.

Mortality of patients with breast cancer is due overwhelmingly to metastatic spread of the disease. Although dissemination is an early event in breast cancer, extended periods of cancer cell dormancy can result in long latency of metastasis development. Deciphering the mechanisms underlying cancer cell dormancy and subsequent growth at the metastatic site would facilitate development of strategies to interfere with these processes. A challenge in this undertaking has been the lack of models for cancer cell dormancy. We have established novel experimental systems that model the bone microenvironment of the breast cancer metastatic niche. These systems are based on 3D cocultures of breast cancer cells with cell types predominant in bone marrow. We identified conditions in which cancer cells are dormant and conditions in which they proliferate. Dormant cancer cells were able to proliferate upon transfer into supportive microenvironment or upon manipulation of signaling pathways that control dormancy. These experimental systems will be instrumental for metastasis studies, particularly the study of cellular dormancy.

A novel model of dormancy for bone metastatic breast cancer cells.

Chemokine signaling is important for the seeding of different sites by hematopoietic stem cells (HSCs) during development. Serum response factor (SRF) controls multiple genes governing adhesion and migration, mainly by recruiting members of the myocardin-related transcription factor (MRTF) family of G-actin-regulated cofactors. We used vav-iCre to inactivate MRTF-SRF signaling early during hematopoietic development. In both Srf- and Mrtf-deleted animals, hematopoiesis in fetal liver and spleen is intact but does not become established in fetal bone marrow. Srf-null HSC progenitor cells (HSC/Ps) fail to effectively engraft in transplantation experiments, exhibiting normal proximal signaling responses to SDF-1, but reduced adhesiveness, F-actin assembly, and reduced motility. Srf-null HSC/Ps fail to polarize in response to SDF-1 and cannot migrate through restrictive membrane pores to SDF-1 or Scf in vitro. Mrtf-null HSC/Ps were also defective in chemotactic responses to SDF-1. Srf-null HSC/Ps exhibit substantial deficits in cytoskeletal gene expression. MRTF-SRF signaling is thus critical for expression of genes required for the response to chemokine signaling during hematopoietic development.

MRTF-SRF signaling is required for seeding of HSC/Ps in bone marrow during development.

Despite advances in our understanding of interactions between mouse hematopoietic stem cells (HSCs) and their niche, little is known about communication between human HSCs and the microenvironment. Using a xenotransplantation model and intravital imaging, we demonstrate that human HSCs display distinct motile behaviors to their hematopoietic progenitor cell (HPC) counterparts, and the same pattern can be found between mouse HSCs and HPCs. HSCs become significantly less motile after transplantation, while progenitor cells remain motile. We show that human HSCs take longer to find their niche than previously expected and suggest that the niche be defined as the position where HSCs stop moving. Intravital imaging is the only technique to determine where in the bone marrow stem cells stop moving, and future analyses should focus on the environment surrounding the HSC at this point.

Different Motile Behaviors of Human Hematopoietic Stem versus Progenitor Cells at the Osteoblastic Niche.

It is widely accepted that complex interactions between cancer cells and their surrounding microenvironment contribute to disease development, chemo-resistance and disease relapse. In light of this observed interdependency, novel therapeutic interventions that target specific cancer stroma cell lineages and their interactions are being sought. Here we studied a mouse model of human T-cell acute lymphoblastic leukaemia (T-ALL) and used intravital microscopy to monitor the progression of disease within the bone marrow at both the tissue-wide and single-cell level over time, from bone marrow seeding to development/selection of chemo-resistance. We observed highly dynamic cellular interactions and promiscuous distribution of leukaemia cells that migrated across the bone marrow, without showing any preferential association with bone marrow sub-compartments. Unexpectedly, this behaviour was maintained throughout disease development, from the earliest bone marrow seeding to response and resistance to chemotherapy. Our results reveal that T-ALL cells do not depend on specific bone marrow microenvironments for propagation of disease, nor for the selection of chemo-resistant clones, suggesting that a stochastic mechanism underlies these processes. Yet, although T-ALL infiltration and progression are independent of the stroma, accumulated disease burden leads to rapid, selective remodelling of the endosteal space, resulting in a complete loss of mature osteoblastic cells while perivascular cells are maintained. This outcome leads to a shift in the balance of endogenous bone marrow stroma, towards a composition associated with less efficient haematopoietic stem cell function. This novel, dynamic analysis of T-ALL interactions with the bone marrow microenvironment in vivo, supported by evidence from human T-ALL samples, highlights that future therapeutic interventions should target the migration and promiscuous interactions of cancer cells with the surrounding microenvironment, rather than specific bone marrow stroma, to combat the invasion by and survival of chemo-resistant T-ALL cells.

T-cell acute leukaemia exhibits dynamic interactions with bone marrow microenvironments.

Adhesion is a key component of hematopoietic stem cell regulation mediating homing and retention to the niche in the bone marrow. Here, using an RNA interference screen, we identify cytohesin 1 (CYTH1) as a critical mediator of adhesive properties in primary human cord blood-derived hematopoietic stem and progenitor cells (HSPCs). Knockdown of CYTH1 disrupted adhesion of HSPCs to primary human mesenchymal stroma cells. Attachment to fibronectin and ICAM1, 2 integrin ligands, was severely impaired, and CYTH1-deficient cells showed a reduced integrin β1 activation response, suggesting that CYTH1 mediates integrin-dependent functions. Transplantation of CYTH1-knockdown cells to immunodeficient mice resulted in significantly lower long-term engraftment levels, associated with a reduced capacity of the transplanted cells to home to the bone marrow. Intravital microscopy showed that CYTH1 deficiency profoundly affects HSPC mobility and localization within the marrow space and thereby impairs proper lodgment into the niche. Thus, CYTH1 is a novel major regulator of adhesion and engraftment in human HSPCs through mechanisms that, at least in part, involve the activation of integrins.

Cytohesin 1 regulates homing and engraftment of human hematopoietic stem and progenitor cells.

The BM niche comprises a tightly controlled microenvironment formed by specific tissue and cells that regulates the behavior of hematopoietic stem cells (HSCs). Here, we have provided a 3D model that is tunable in different BM niche components and useful, both in vitro and in vivo, for studying the maintenance of normal and malignant hematopoiesis. Using scaffolds, we tested the capacity of different stromal cell types to support human HSCs. Scaffolds coated with human mesenchymal stromal cells (hMSCs) proved to be superior in terms of HSC engraftment and long-term maintenance when implanted in vivo. Moreover, we found that hMSC-coated scaffolds can be modulated to form humanized bone tissue, which was also able to support human HSC engraftment. Importantly, hMSC-coated humanized scaffolds were able to support the growth of leukemia patient cells in vivo, including the growth of samples that would not engraft the BM of immunodeficient mice. These results demonstrate that an s.c. implantation approach in a 3D carrier scaffold seeded with stromal cells is an effective in vivo niche model for studying human hematopoiesis. The various niche components of this model can be changed depending on the context to improve the engraftment of nonengrafting acute myeloid leukemia (AML) samples.

Katie Foster

Haematopoietic Stem Cell Laboratory

The Francis Crick Institute

Bioengineering of Humanized Bone Marrow Microenvironments in Mouse and Their Visualization by Live Imaging

Katie Foster

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The Francis Crick Institute

Bioengineering of Humanized Bone Marrow Microenvironments in Mouse and Their Visualization by Live Imaging

Haematopoietic Stem Cell Laboratory