我们感谢康涅狄格大学健康中心流式细胞术核心的 Evan Jellison 博士和 Li Zhu 女士在流式细胞术方面的帮助，感谢康涅狄格大学健康中心免疫学系的 Lynn Puddington 博士对仪器的支持，感谢康涅狄格大学健康中心临床研究核心的 Slawa Gajewska 女士和 Paul Appleton 博士在获取血液样本方面的帮助。我们感谢康涅狄格大学医学院的 Christopher “Kit” Bonin 博士和 Geneva Hargis 博士在科学写作和编辑本手稿方面提供的帮助。这项研究得到了美国国立卫生研究院、美国国家心脏、肺和血液研究所 （R01HL145454）、美国国家普通医学科学研究所 （P20GM121176）、美国心脏协会职业发展奖 （18CDA34110426） 和康涅狄格大学健康中心的启动基金的支持。 图 1 是使用 BioRender.com 创建的。

根据《赫尔辛基宣言》的原则，在获得知情同意后，从去识别化的健康人类供体处获得肝素化全血样本，经康涅狄格大学健康机构审查委员会批准。已获得所有捐赠者的知情同意。本研究的纳入/排除标准经过精心制定，以确保受试者的适用性并将潜在风险降至最低。符合条件的参与者年龄在 18 至 65 岁之间，不分种族，英语流利，能够提供知情同意。被排除在外的受试者包括那些无法为自己提供知情同意的人，例如那些需要合法授权代表的人、18岁以下或65岁以上的个人、被监禁的人和孕妇。此外，参与者必须没有使用抗炎药物和炎症。当前感染或持续的慢性或急性炎症性疾病也是排除标准。最后，当前或近期有 COVID-19 感染史的个体不符合该研究的资格。这些标准旨在确保参与者的安全性和适用性，同时最大限度地减少可能影响研究结果的潜在混杂因素。
1.试剂的制备
<ol><li>中性粒细胞培养基：通过向不含酚红的RPMI-1640中加入2%人血清白蛋白来制备中性粒细胞培养基（参见 材料表）。</li>
	<li>fMLP溶液：用不含酚红的RPMI 1640从10mM fMLP二甲基亚砜（DMSO）储存溶液（参见 材料表）中稀释100倍来制备fMLP溶液，得到100μM fMLP溶液。</li>
	<li>抗体溶液：在 10 mL 中性粒细胞培养基中稀释 120 μL 别藻蓝蛋白 （APC） 偶联单克隆抗体 mAb24 （mAb24-APC）（参见 材料表），该抗体报告了 β2 整合素的高亲和力构象，形成 1.2 μg/mL mAb24-APC 溶液。</li>
	<li>化合物库：通过使用液体处理器将 5 μL 的 10 mM 文库（参见 材料表）加入 384 孔板中的 45 μL DMSO 中，将浓度为 10 mM 至 1 mM 的初始化合物库稀释至 1 mM。随后，使用液体处理器将每孔 5 μL 的 1 mM 化合物库转移到空的 384 孔板中。</li>
	<li>如图1所示，四列（ 1、2、23、24）仅含有DMSO，不含化合物，在筛选中作为阳性和阴性对照。通过加入 45 μL 不含酚红的 RPMI-1640 进一步稀释每个孔，使所有化合物的最终浓度为 100 μM。</li>
</ol>2. 从人体血液中分离中性粒细胞
<ol><li>使用血清移液管，在15mL离心管中小心地将4mL血液分层在8mL市售密度梯度培养基（参见 材料表）（图2A）中。</li>
	<li>将血液在20°C下以550× g 离心30-50分钟。 逐渐使转子减速（减速系数为1）。 注意：中性粒细胞（ 图2B中的条带2）从红细胞中成功分离可能因供体而异。对于大多数供体，30 分钟的离心就足够了。然而，对于一些供体，如果分离不成功，可能需要额外的10-30分钟离心（图2C）。</li>
	<li>小心地去除血浆（顶部的黄色液体）和单核细胞（上部混浊带; 图2B中的PBMC条带）使用1 mL移液管。</li>
	<li>将中性粒细胞从下部混浊带（ 图2B中的中性粒细胞带）收集，并在透明液体下方约3-4mL收集到含有10mL磷酸盐缓冲盐水（PBS）的15mL离心管中。将中性粒细胞悬浮液倒置2-3次，轻轻混合。</li>
	<li>将悬浮液在400× g 下在20°C下离心10分钟，然后通过倾析小心地除去上清液。</li>
	<li>用5mL PBS轻轻重悬沉淀，并在20°C下以300× g 离心5分钟。</li>
	<li>通过倾析除去上清液，并使用真空抽吸小心地清除管口周围和管壁上的任何残留上清液。将沉淀重悬于 1 mL 中性粒细胞培养基中。</li>
	<li>使用血细胞计数器计数细胞数。通常，从 8 mL 人血中获得 1 至 4 ×10 7 个中性粒细胞。 注意：中性粒细胞悬浮液中可能存在红细胞污染。红细胞不会显著影响大多数检测，并且可以防止中性粒细胞活化/启动27.红细胞在计数前需要裂解，以获得准确的中性粒细胞浓度。将 10 μL 细胞悬液加入 891 μL 去离子水中 10-30 秒以裂解红细胞，然后加入 99 μL 10× PBS 以平衡渗透压，防止中性粒细胞裂解。</li>
	<li>通过加入中性粒细胞培养基，将细胞密度调节至 6.25 ×10 5 个细胞/mL。</li>
</ol>3. 384孔板的制备
<ol><li>在 1.5 mL 离心管中，将 1 mL 抗体溶液 （1.2 μg/mL mAb24-APC） 与 0.2 mL 中性粒细胞培养基混合，制备 1 μg/mL mAb24-APC 溶液。然后，将 25 μL 该混合物加入 384 孔板（ 图 1 中的蓝色孔）中的阴性对照孔中。</li>
	<li>在 15 mL 离心管中，将 9 mL 抗体溶液与 21.6 μL fMLP 溶液 （100 μM） 和 1.7784 mL 中性粒细胞培养基混合，以制备含有 1 μg/mL mAb24-APC 和 200 nM fMLP 的溶液。接下来，将 25 μL 该混合物加入 384 孔板（ 图 1 中的红色和蓝色孔）中的阳性对照和测试孔中。</li>
	<li>使用多通道移液器将 5 μL 的 100 μM 化合物溶液从化合物库板转移到 384 孔板中。</li>
	<li>在室温下以500× g离心液体1分钟。 注意： 要离心板，需要一个水平桶转子和板桶。</li>
</ol>4.细胞处理
<ol><li>使用 16 通道移液器（5-50 μL 范围，384 孔板的每列）向每个孔中加入 20 μL 中性粒细胞悬浮液。使用移液管轻轻混合 5-10 次，每次移液之间保持一致的时间间隔。 注：孔中的最终浓度如下：中性粒细胞 2.5 × 105 个细胞/mL（所有孔）;mAb24-APC 0.5 μg/mL（所有孔）;fMLP 100 nM（阳性对照和测试孔）;化合物 10 μM（测试孔）。</li>
	<li>在室温（RT）下，在300rpm的振荡器上孵育板10分钟。</li>
	<li>使用16通道移液管（最终PFA浓度~0.91%）向每个孔中加入3μL的16%多聚甲醛（PFA）来固定细胞。然后，在冰上孵育10分钟。 注意：建议在添加中性粒细胞和PFA时，不同色谱柱之间保持一致的时间间隔。这确保了每个孔中的中性粒细胞与 fMLP 和 mAb24-APC 具有相同的孵育时间。</li>
</ol>5. 流式细胞术
<ol><li>打开流式细胞仪（见 材料表），并确保连接到仪器的计算机也已打开。</li>
	<li>确保鞘液容器已装满，废液容器为空并正确连接到仪器。</li>
	<li>将 384 孔板加载到流式细胞仪的样品加载器上。确保板的 A1 孔与装载机上的 A1 标记对齐。</li>
	<li>打开软件并创建一个新实验。选择 384 孔 并选择所需的荧光基团。接下来，单击“ 板设置”，拖动以选择所有孔，然后单击 “样品”。打开“高吞吐量”开关，然后在速率面板下选择 高 。<ol><li>在音量框中，输入 50。在奇数列中选择样品，然后激活“搅拌”开关。最后，在右侧面板中命名示例。</li>
	</ol></li>
	<li>单击 “绘图和门”。然后，单击 “应用 ”按钮（绿色填充圆圈上的两个箭头），随后单击 播放 按钮（三角形）。等待几秒钟以观察第一个孔中的一些细胞，然后单击 暂停 按钮。<ol><li>调整 FSC 和 SSC 电压，以确保图上细胞的正确可视化。单击 “采集”，然后单击 播放 按钮（三角形）以开始检测。</li>
	</ol></li>
	<li>流式细胞仪将依次从每个孔中取样 ~50 μL 的 1000-3000 个中性粒细胞。完成整个 384 孔板大约需要 3 小时。</li>
	<li>完成所有示例后，导出 .fcs 文件以供下一步使用。</li>
</ol>6. 数据分析
<ol><li>打开流式细胞术数据分析软件（参见 材料表）。选择包含所有 .fcs 文件的文件夹并将其拖动到软件窗口中，然后松开以将数据导入软件。</li>
	<li>双击一个样品，在弹出的窗口中基于FSC和SSC28,29,30的单个中性粒细胞进行门控，如图3所示。选择门控行并将它们拖动到文件夹中，然后松开以将门控应用于该文件夹中的所有样本。</li>
	<li>使用软件的表格编辑器功能计算并导出每个孔中嗜中性粒细胞的 APC 中值荧光强度 （MFI）。单击“编辑”选项卡下的“添加列”。在统计选项卡中选择中位数，选择门控群体中性粒细胞，然后选择 APC 作为参数。单击“确定”按钮。</li>
	<li>返回“表格编辑器”选项卡，在“组”选项卡中选择 “所有样品 ”，然后按 “创建表格 ”按钮。将出现一个新窗口，显示创建的表。将其另存为文本、CSV 或 Excel 文件。</li>
	<li>打开导出的表格，计算阳性和阴性对照样品的APC MFI的平均值和标准偏差（图4）。</li>
	<li>使用以下公式计算板的 Z' 因子 （Z'）： Z' = 1 - 3（σ p + σ n）/（μp - μn）， 其中 σ p 和 σ n 分别是阳性和阴性对照的标准差，μp 和 μn 分别是阳性和阴性对照的平均值31. 注： Z' 因子表示正负对照分布的分离。Z' 为 0 表示没有分离，而 Z' 为 0.5 表示相等的分离。如先前的研究31 所述，Z' > 0.5 表示化合物筛选的极好测定方法。0.5 到 0 范围内的 Z' 是可以接受的，但它可能只能识别检测中的强命中，这需要在二次检测中进一步验证。</li>
	<li>当化合物处理的中性粒细胞的APC MFI低于从阳性对照MFI中减去阳性对照MFI标准差的三倍时，将化合物视为筛选的“命中”（P = 0.0013，由 图4中的虚线表示）。</li>
</ol>

人中性粒细胞中 β2 整合素激活抑制剂的筛选

<ol>
	<li>Herrero-Cervera, A., Soehnlein, O., Kenne, E. Neutrophils in chronic inflammatory diseases. Cellular &#38; Molecular Immunology. 19 (2), 177-191 (2022).</li>
	<li>Sadik, C. D., Kim, N. D., Luster, A. D. Neutrophils cascading their way to inflammation. Trends in immunology. 32 (10), 452-460 (2011).</li>
	<li>Mitroulis, I. et al. Leukocyte integrins: Role in leukocyte recruitment and as therapeutic targets in inflammatory disease. Pharmacology &#38; Therapeutics. 147, 123-135 (2015).</li>
	<li>Slack, R. J., Macdonald, S. J. F., Roper, J. A., Jenkins, R. G., Hatley, R. J. D. Emerging therapeutic opportunities for integrin inhibitors. Nature Reviews Drug Discovery. 21 (1), 60-78 (2022).</li>
	<li>Frampton, J. E., Plosker, G. L. Efalizumab. American Journal of Clinical Dermatology. 10 (1), 51-72 (2009).</li>
	<li>Talamonti, M. et al. Efalizumab. Expert Opinion on Drug Safety. 10 (2), 239-251 (2011).</li>
	<li>Sariba&#351;, A. S., &#214;zdemir, A., Lam, C., Safak, M. JC virus-induced progressive multifocal leukoencephalopathy. Future Virology. 5 (3), 313-323 (2010).</li>
	<li>Chames, P., Van Regenmortel, M., Weiss, E., Baty, D. Therapeutic antibodies: successes, limitations and hopes for the future. British Journal of Pharmacology. 157 (2), 220-233 (2009).</li>
	<li>Mancuso, R. V., Casper, J., Schmidt, A. G., Kr&#228;henb&#252;hl, S., Weitz-Schmidt, G. Anti-&#945;L&#946;2 antibodies reveal novel endocytotic cross-modulatory functionality. British Journal of Pharmacology. 177 (12), 2696-2711 (2020).</li>
	<li>Anderson, J. M., Li, J., Springer, T. A. Regulation of integrin &#945;5&#946;1 conformational states and intrinsic affinities by metal ions and the ADMIDAS. Molecular Biology of the Cell. 33 (6), ar56 (2022).</li>
	<li>Jensen, R. K. et al. Complement receptor 3 forms a compact high-affinity complex with iC3b. The Journal of Immunology. 206 (12), 3032-3042 (2021).</li>
	<li>Li, J., Yan, J., Springer, T. A. Low affinity integrin states have faster ligand binding kinetics than the high affinity state. Elife. 10, e73359 (2021).</li>
	<li>Luo, B. H., Carman, C. V., Springer, T. A. Structural basis of integrin regulation and signaling. Annual Review of Immunology. 25, 619-647 (2007).</li>
	<li>Fan, Z. et al. Neutrophil recruitment limited by high-affinity bent &#946;2 integrin binding ligand in cis. Nature communications. 7 (1), 1-14 (2016).</li>
	<li>Fan, Z. et al. High-affinity bent &#946;2-integrin molecules in arresting neutrophils face each other through binding to ICAMs in cis. Cell reports. 26 (1), 119-130 (2019).</li>
	<li>Gupta, V. et al. The &#946;-tail domain (&#946;TD) regulates physiologic ligand binding to integrin CD11b/CD18. Blood. 109 (8), 3513-3520 (2006).</li>
	<li>Sen, M., Yuki, K., Springer, T. A. An internal ligand-bound, metastable state of a leukocyte integrin, &#945;X&#946;2. Journal of Cell Biology. 203 (4), 629-642 (2013).</li>
	<li>Sun, H., Hu, L., Fan, Z. &#946;2 integrin activation and signal transduction in leukocyte recruitment. American Journal of Physiology-Cell Physiology. 321 (2), C308-C316 (2021).</li>
	<li>Sun, H., Zhi, K., Hu, L., Fan, Z. The activation and regulation of &#946;2 integrins in phagocytes. Frontiers in Immunology. 12, 978 (2021).</li>
	<li>Kamata, T. et al. The role of the CPNKEKEC sequence in the &#946;2 subunit I domain in regulation of integrin &#945;L&#946;2 (LFA-1). The Journal of Immunology. 168 (5), 2296-2301 (2002).</li>
	<li>Lu, C., Shimaoka, M., Zang, Q., Takagi, J., Springer, T. A. Locking in alternate conformations of the integrin &#945;L&#946;2 I domain with disulfide bonds reveals functional relationships among integrin domains. Proceedings of the National Academy of Sciences. 98 (5), 2393-2398 (2001).</li>
	<li>Yang, W., Shimaoka, M., Chen, J., Springer, T. A. Activation of integrin &#946;-subunit I-like domains by one-turn C-terminal &#945;-helix deletions. Proceedings of the National Academy of Sciences. 101 (8), 2333-2338 (2004).</li>
	<li>Dransfield, I., Hogg, N. Regulated expression of Mg2+ binding epitope on leukocyte integrin alpha subunits. The EMBO Journal. 8 (12), 3759-3765 (1989).</li>
	<li>Torres, M., Hall, F., O&#39;neill, K. Stimulation of human neutrophils with formyl-methionyl-leucyl-phenylalanine induces tyrosine phosphorylation and activation of two distinct mitogen-activated protein-kinases. The Journal of Immunology. 150 (4), 1563-1577 (1993).</li>
	<li>Dorward, D. A. et al. The role of formylated peptides and formyl peptide receptor 1 in governing neutrophil function during acute inflammation. The American Journal of Pathology. 185 (5), 1172-1184 (2015).</li>
	<li>Lin, F. Y. et al. A general chemical principle for creating closure-stabilizing integrin inhibitors. Cell. 185 (19), 3533-3550 (2022).</li>
	<li>Lizcano, A. et al. Erythrocyte sialoglycoproteins engage Siglec-9 on neutrophils to suppress activation. Blood, The Journal of the American Society of Hematology. 129 (23), 3100-3110 (2017).</li>
	<li>Tadema, H., Abdulahad, W. H., Stegeman, C. A., Kallenberg, C. G., Heeringa, P. Increased expression of Toll-like receptors by monocytes and natural killer cells in ANCA-associated vasculitis. PloS One. 6 (9), e24315 (2011).</li>
	<li>Nagelkerke, S. Q., aan de Kerk, D. J., Jansen, M. H., van den Berg, T. K., Kuijpers, T. W. Failure to detect functional neutrophil B helper cells in the human spleen. PloS one. 9 (2), e88377 (2014).</li>
	<li>Blanco-Camarillo, C., Alem&#225;n, O. R., Rosales, C. Low-density neutrophils in healthy individuals display a mature primed phenotype. Frontiers in Immunology. 12, 672520 (2021).</li>
	<li>Zhang, J. H., Chung, T. D., Oldenburg, K. R. A simple statistical parameter for use in evaluation and validation of high throughput screening assays. Journal of biomolecular screening. 4 (2), 67-73 (1999).</li>
	<li>Shimaoka, M., Salas, A., Yang, W., Weitz-Schmidt, G., Springer, T.A. Small molecule integrin antagonists that bind to the &#946;2 subunit I-like domain and activate signals in one direction and block them in the other. Immunity. 19 (3), 391-402 (2003).</li>
	<li>Liu, W. et al. Nexinhib20 Inhibits neutrophil adhesion and &#946;2 integrin activation by antagonizing Rac-1-Guanosine 5&#8242;-Triphosphate interaction. The Journal of Immunology. 209 (8), 1574-1585 (2022).</li>
	<li>Robinson, M. et al. Antibody against the Leu-CAM beta-chain (CD18) promotes both LFA-1-and CR3-dependent adhesion events. The Journal of Immunology. 148 (4), 1080-1085 (1992).</li>
	<li>Lu, C., Ferzly, M., Takagi, J., Springer, T. A. Epitope mapping of antibodies to the C-terminal region of the integrin &#946;2 subunit reveals regions that become exposed upon receptor activation. The Journal of Immunology. 166 (9), 5629-5637 (2001).</li>
	<li>Mauler, M. et al. Platelet serotonin aggravates myocardial ischemia/reperfusion injury via neutrophil degranulation. circulation. 139 (7), 918-931 (2019).</li>
	<li>Shen, X. F., Cao, K., Jiang, J., Guan, W. X., Du, J. F. Neutrophil dysregulation during sepsis: an overview and update. Journal of Cellular and Molecular Medicine. 21 (9), 1687-1697 (2017).</li>
	<li>Chiang, C. C., Cheng, W. J., Korinek, M., Lin, C. Y., Hwang, T. L. Neutrophils in Psoriasis. Frontiers in Immunology. 10, 02376 (2019).</li>
	<li>Lood, C. et al. Neutrophil extracellular traps enriched in oxidized mitochondrial DNA are interferogenic and contribute to lupus-like disease. Nature medicine. 22 (2), 146-153 (2016).</li>
	<li>Bazzoni, G., Shih, D. T., Buck, C. A., Hemler, M. E. Monoclonal antibody 9EG7 defines a novel &#946;1 integrin epitope induced by soluble ligand and manganese, but inhibited by calcium. Journal of Biological Chemistry. 270 (43), 25570-25577 (1995).</li>
	<li>Luque, A. et al. Activated conformations of very late activation integrins detected by a group of antibodies (HUTS) specific for a novel regulatory region(355-425) of the common &#946;1 chain. Journal of Biological Chemistry. 271 (19), 11067-11075 (1996).</li>
	<li>Mould, A. P., Akiyama, S. K., Humphries, M. J. The inhibitory Anti-&#946;1 integrin monoclonal antibody 13 recognizes an epitope that is attenuated by ligand occupancy: evidence for allosteric inhibition of integrin function. Journal of Biological Chemistry. 271 (34), 20365-20374 (1996).</li>
	<li>Spiess, M. et al. Active and inactive &#946;1 integrins segregate into distinct nanoclusters in focal adhesions. Journal of Cell Biology. 217 (6), 1929-1940 (2018).</li>
	<li>Yang, S. et al. Relating conformation to function in integrin &#945;5&#946;1. Proceedings of the National Academy of Sciences. 113 (27), E3872-E3881 (2016).</li>
	<li>Shattil, S. J., Hoxie, J. A., Cunningham, M., Brass, L. F. Changes in the platelet membrane glycoprotein IIb.IIIa complex during platelet activation. Journal of Biological Chemistry. 260 (20), 11107-11114 (1985).</li>
	<li>Shattil, S. J., Motulsky, H. J , Insel, P. A., Flaherty, L., Brass, L. F. Expression of fibrinogen receptors during activation and subsequent desensitization of human platelets by epinephrine. Blood. 68 (6), 1224-1231 (1986).</li>
	<li>Carre&#241;o, R. et al. 2E8 binds to the high affinity i-domain in a metal ion-dependent manner: a second generation monoclonal antibody selectively targeting activated LFA-1. Journal of Biological Chemistry. 285 (43), 32860-32868 (2010).</li>
	<li>Keizer, G. D., Visser, W., Vliem, M., Figdor, C. G. A monoclonal antibody (NKI-L16) directed against a unique epitope on the alpha-chain of human leukocyte function-associated antigen 1 induces homotypic cell-cell interactions. The Journal of Immunology. 140 (5), 1393-1400 (1988).</li>
	<li>Lefort, C. T. et al. Distinct roles for talin-1 and kindlin-3 in LFA-1 extension and affinity regulation. Blood. 119 (18), 4275-4282 (2012).</li>
	<li>van Kooyk, Y. et al. Activation of LFA-1 through a Ca2(+)-dependent epitope stimulates lymphocyte adhesion. Journal of Cell Biology. 112 (2), 345-354 (1991).</li>
	<li>Mould, A. P. et al. Conformational changes in the integrin a domain provide a mechanism for signal transduction via hybrid domain movement. Journal of Biological Chemistry. 278 (19), 17028-17035 (2003).</li>
	<li>Chigaev, A. et al. Real-time analysis of conformation-sensitive antibody binding provides new insights into integrin conformational regulation. Journal of Biological Chemistry. 284 (21), 14337-14346 (2009).</li>
	<li>Njus, B. H. et al. Conformational mAb as a tool for integrin ligand discovery. Assay and Drug Development Technologies. 7 (5), 507-515 (2009).</li>
	<li>Chigaev, A., Wu, Y., Williams, D. B., Smagley, Y., Sklar, L. A. Discovery of very late antigen-4 (VLA-4, &#945;4&#946;1 integrin) allosteric antagonists. Journal of Biological Chemistry. 286 (7), 5455-5463 (2011).</li>
	<li>Ghigo, A., De Santi, C., Hart, M., Mitash, N., Swiatecka-Urban, A. Cell signaling and regulation of CFTR expression in cystic fibrosis cells in the era of high efficiency modulator therapy. Journal of Cystic Fibrosis. 22, S12-S16 (2023).</li>
	<li>Van Goor, F., Yu, H., Burton, B., Hoffman, B.J. Effect of ivacaftor on CFTR forms with missense mutations associated with defects in protein processing or function. Journal of Cystic Fibrosis. 13 (1), 29-36 (2014).</li>
</ol>

作者声明没有相互竞争的经济利益。

中性粒细胞刺激和染色的开始和终止由添加中性粒细胞和固定剂PFA来确定。因此，确保将中性粒细胞或PFA移液到每根色谱柱中的时间间隔相同至关重要。这确保了每个孔中嗜中性粒细胞的刺激和染色时间保持一致。由于中性粒细胞的寿命较短，从从供体采集血液到完成流式细胞术的整个实验必须在同一天进行。中性粒细胞对温度变化高度敏感，当暴露于温度快速升高时，例如从4°C过渡到室温或从...

许多炎症性疾病的特征在于中性粒细胞浸润在肿胀或损伤部位1。为了浸润这些组织，中性粒细胞必须完成中性粒细胞募集级联反应，包括阻滞到内皮细胞，外渗穿过血管壁，然后募集到组织中2。循环中性粒细胞需要β2整合素激活才能完成这一级联反应，特别是在停滞阶段。因此，减少中性粒细胞粘附、外渗和募集的整合素抑制药物可有效治疗炎症性疾病 3,4。
β2整合素以前曾被靶向用于炎症性疾病。依法珠单抗是一种直接靶向整合素αLβ2的单克隆抗体，用于治疗银屑病5。然而，依法珠单抗因其致命的副作用而被撤回 - JC病毒再激活导致的进行性多灶性白质脑病6,7。基于整合素的新型抗炎疗法应考虑维持白细胞的抗感染功能，以尽量减少副作用。依法珠单抗的副作用可能是由于单克隆抗体在血液中的循环时间延长，从长远来看可能会抑制免疫功能8.最近的一项研究表明，依法利珠单抗介导 αLβ2 交联和 α4 整合素的不需要的内化，为副作用提供了另一种解释9.因此，短寿命的小分子拮抗剂可能会避免这个问题。
本文介绍了一种使用人中性粒细胞筛选小分子β2整合素拮抗剂的高通量方法。β2 整合素激活需要整合素胞外结构域的构象变化才能进入并增加其与其配体的结合亲和力。在规范的弹簧刀模型中，弯曲闭合的整合素胞外结构域首先延伸到扩展-闭合构象，然后打开其头件以完全激活的扩展-开放构象10,11,12,13。还有另一种途径，从弯曲闭合到弯曲打开和扩展打开，最终是14、15、16、17、18、19。构象特异性抗体 mAb24 与人 β2-I 样结构域中的表位结合，当胞外结构域的头饰打开时20,21,22,23。
在这里，mAb24-APC 用于确定 β2 整合素是否被激活。为了激活中性粒细胞和整合素，N-甲酰甲硫酰-亮氨酰-苯丙氨酸 （fMLP），一种细菌衍生的短趋化肽，可以激活中性粒细胞 β2 整合素24，在该方案中用作刺激物。当 fMLP 与中性粒细胞上的 Fpr1 结合时，涉及 G 蛋白、磷脂酶 Cβ 和磷酸肌醇 3-激酶γ的下游信号级联被激活。这些信号转导事件最终通过由内而外的信号通路18,25 导致整合素激活。除了直接与β2整合素结合并阻止整合素活化构象变化的小分子拮抗剂26外，该方法还可以检测出可以抑制β2整合素由内而外的激活信号通路中成分的化合物。自动流式细胞仪可实现高通量筛选。识别新的拮抗剂不仅可以加深我们对整合素生理学的理解，还可以为基于整合素的抗炎治疗提供转化见解。

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		<tr>
			<td>16-channel pipettes</td>
			<td>Thermo</td>
			<td>4661090N</td>
			<td>Instrument</td>
		</tr>
		<tr>
			<td>384-well plate</td>
			<td>Greiner</td>
			<td>784201</td>
			<td>Materials</td>
		</tr>
		<tr>
			<td>APC anti-human CD11a/CD18 (LFA-1) Antibody Clone: m24</td>
			<td>BioLegend</td>
			<td>363410</td>
			<td>Reagents</td>
		</tr>
		<tr>
			<td>Bravo&#160;Automated Liquid Handling Platform&#160;</td>
			<td>Agilent</td>
			<td>16050-102</td>
			<td>384 multi-channel liquid handler</td>
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		<tr>
			<td>Centrifuge</td>
			<td>Eppendorf</td>
			<td>Model 5810R</td>
			<td>Instrument</td>
		</tr>
		<tr>
			<td>FlowJo</td>
			<td>Becton, Dickinson &#38; Company</td>
			<td>NA</td>
			<td>Software</td>
		</tr>
		<tr>
			<td>Human Serum Albumin Solution (25%)</td>
			<td>GeminiBio</td>
			<td>800-120</td>
			<td>Reagents</td>
		</tr>
		<tr>
			<td>Lifitegrast</td>
			<td>Thermofisher</td>
			<td>&#160;50-208-2121</td>
			<td>Reagents</td>
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		<tr>
			<td>Nexinhib20</td>
			<td>Tocris</td>
			<td>6089</td>
			<td>Reagents</td>
		</tr>
		<tr>
			<td>N-Formyl-Met-Leu-Phe (fMLP)</td>
			<td>Sigma</td>
			<td>F3506</td>
			<td>Reagents</td>
		</tr>
		<tr>
			<td>Paraformaldehyde 16% solution</td>
			<td>Electron Microscopy Sciences</td>
			<td>15710</td>
			<td>Reagents</td>
		</tr>
		<tr>
			<td>Plate buckets</td>
			<td>Eppendorf</td>
			<td>UL155</td>
			<td>Accessory</td>
		</tr>
		<tr>
			<td>Plate shaker&#160;</td>
			<td>Fisher</td>
			<td>88-861-023</td>
			<td>Instrument</td>
		</tr>
		<tr>
			<td>PolymorphPrep</td>
			<td>PROGEN</td>
			<td>1895 (previous 1114683)</td>
			<td>Reagents</td>
		</tr>
		<tr>
			<td>Prestwick Chemical Library Compound Plates (10 mM)</td>
			<td>Prestwick Chemical Libraries</td>
			<td>Ver19_384</td>
			<td>1520 small molecules, 98% marketed approved drugs (FDA, EMA, JAN, and other agencies approved)</td>
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		<tr>
			<td>RPMI 1640 Medium, no phenol red</td>
			<td>Gibco</td>
			<td>11-835-030</td>
			<td>Reagents</td>
		</tr>
		<tr>
			<td>Swing-bucket rotor&#160;</td>
			<td>Eppendorf</td>
			<td>A-4-62</td>
			<td>Rotor</td>
		</tr>
		<tr>
			<td>ZE5 Cell Analyzer</td>
			<td>Bio-Rad Laboratories</td>
			<td>Model ZE5</td>
			<td>Instrument</td>
		</tr>
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a flow cytometry-based high-throughput technique for screening integrin-inhibitory drugs

该方案旨在建立一种利用构象变化报告抗体和高通量流式细胞术鉴定β2整合素活化的小分子拮抗剂的方法。该方法还可以作为其他基于抗体的高通量筛选方法的指南。β2整合素是白细胞特异性粘附分子，在免疫反应中至关重要。中性粒细胞依靠整合素活化排出血液，不仅可以抵抗感染，还可以参与多种炎症性疾病。控制β2整合素活化是治疗中性粒细胞相关炎症性疾病的可行方法。在该方案中，单克隆抗体 mAb24 与 β2 整合素的高亲和力头片特异性结合，用于定量分离的原代人中性粒细胞上的 β2 整合素活化。N-甲酰甲硫酰-亮氨酰-苯丙氨酸 （fMLP） 用作激活中性粒细胞 β2 整合素的刺激物。本研究使用了能够自动运行 384 孔板样品的高通量流式细胞仪。在3小时内评估320种化学物质对β2整合素抑制的影响。通过这种方法可以识别直接靶向β2整合素的分子或G蛋白偶联受体启动的整合素由内而外的激活信号通路中的靶分子。

Many inflammatory diseases are characterized by the infiltration of neutrophils at the site of swelling or injury1. To infiltrate these tissues, neutrophils must complete the neutrophil recruitment cascade, which involves arrest to the endothelium, extravasation across the vessel wall, and recruitment into the tissue2. Circulating neutrophils need &#946;2 integrin activation to complete this cascade, especially for the arrest phase. Thus, integrin-inhibiting drugs that reduce neutrophil adhesion, extravasation, and recruitment may effectively treat inflammatory diseases3,4.
&#946;2 integrins have been targeted for inflammatory diseases before. Efalizumab, a monoclonal antibody directly targeting integrin &#945;L&#946;2, was developed to treat psoriasis5. However, efalizumab was withdrawn due to its lethal side effect - progressive multifocal leukoencephalopathy resulting from JC virus reactivation6,7. New anti-inflammatory integrin-based therapies should consider maintaining the anti-infection functions of leukocytes to minimize side effects. The side effects of efalizumab might be due to the prolonged circulation of monoclonal antibodies in the bloodstream, which could inhibit immune functions in the long term8. A recent study shows that efalizumab mediates &#945;L&#946;2 crosslinking and the unwanted internalization of &#945;4 integrins, providing an alternative explanation for the side effects9. Thus, short-lived, small-molecule antagonists might avoid this problem.
A high-throughput method to screen small-molecule &#946;2 integrin antagonists using human neutrophils is presented here. &#946;2 integrin activation requires conformational changes of the integrin ectodomain to gain access to and increase its binding affinity to its ligand. In the canonical switchblade model, the bent-closed integrin ectodomain first extends to an extended-closed conformation and then opens its headpiece to a fully activated extended-open conformation10,11,12,13. There is also an alternative pathway that starts from the bent-closed to bent-open and extended-open, eventually14,15,16,17,18,19. The conformation-specific antibody mAb24 binds to an epitope in the human &#946;2-I-like domain when the headpiece of the ectodomain is open20,21,22,23.
Here, mAb24-APC is used to determine whether the &#946;2 integrins are activated. To activate neutrophils and integrin, N-formylmethionyl-leucyl-phenylalanine (fMLP), a bacterial-derived short chemotactic peptide that can activate neutrophil &#946;2 integrins24, is used as a stimulus in this protocol. When fMLP binds to the Fpr1 on neutrophils, downstream signaling cascades involving G-proteins, phospholipase C&#946;, and phosphoinositide 3-kinase &#947; are activated. These signaling events ultimately result in integrin activation via the inside-out signaling pathway18,25. Besides small molecule antagonists that directly bind to &#946;2 integrins and prevent conformational changes of integrin activation26, compounds that can inhibit components in the &#946;2 integrin inside-out activation signaling pathway would also be detected with this method. Automated flow cytometers enable high-throughput screening. Identifying new antagonists may not only deepen our understanding of integrin physiology but also provide translational insight into integrin-based anti-inflammation therapy.

作者聚焦：鉴定 β2 整合素激活小分子拮抗剂的方法的开发 

一种基于流式细胞术的高通量技术筛选整合素抑制药物

Our research is focused on neutrophil integrin, and in this study we aim to establish a method to find small molecular antagonists of Beta-2 integrin activation. We believe with this method we can find new antagonists that may deepen our understanding in integrin physiology, and also provide translational insight into integrin-based anti-inflammatory therapy. In the future, we will focus on discovering new anti-inflammatory drugs and dissecting their mechanisms of action.

来自代表性的 384 孔板筛选的数据（图 4）显示，阴性对照的 mAb24-APC MFI 为 3236 ± 110，而阳性对照的 mAb24-APC MFI 为 7588 ± 858。该板的 Z' 因子约为 0.33，在可接受的范围内31。然而，Z'需要在二次测定中进一步验证。
为了对数据进行归一化，对所有值进行了缩放，以将最大值 1 分配给正均值，将最小值 0 分配给负均值。Z'因子将在二次测定?...

Watch this Scientific Journal Video about Development of a Method for Identifying Small Molecular Antagonists of β2 Integrin Activation at JoVE.com

该协议描述了一种基于流式细胞术的高通量筛选方法，用于鉴定抑制人中性粒细胞上β2整合素活化的小分子药物。

This protocol aims to establish a method for identifying small molecular antagonists of &#946;2 integrin activation, utilizing ...

我们的研究重点是中性粒细胞整合素，在这项研究中，我们旨在建立一种寻找β-2整合素激活的小分子拮抗剂的方法。我们相信，通过这种方法，我们可以找到新的拮抗剂，这些拮抗剂可能会加深我们对整合素生理学的理解，并为基于整合素的抗炎疗法提供转化见解。未来，我们将专注于发现新的抗炎药并剖析其作用机制。

a-flow-cytometry-based-high-throughput-technique-for-screening

Research

JoVE Journal

Immunology and Infection

A Flow Cytometry-Based High-Throughput Technique for Screening Integrin-Inhibitory Drugs

1.1K 次观看.  UConn Health. 我们的研究重点是中性粒细胞整合素，在这项研究中，我们旨在建立一种寻找β-2整合素激活的小分子拮抗剂的方法。我们相信，通过这种方法，我们可以找到新的拮抗剂，这些拮抗剂可能会加深我们对整合素生理学的理解，并为基于整合素的抗炎疗法提供转化见解。未来，我们将专注于发现新的抗炎药并剖析其作用机制。

视频: 作者聚焦：鉴定 β2 整合素激活小分子拮抗剂的方法的开发 

This protocol aims to establish a method for identifying small molecular antagonists of &#946;2 integrin activation, utilizing conformational-change-reporting antibodies and high-throughput flow cytometry. The method can also serve as a guide for other antibody-based high-throughput screening methods. &#946;2 integrins are leukocyte-specific adhesion molecules that are crucial in immune responses. Neutrophils rely on integrin activation to exit the bloodstream, not only to fight infections but also to be involved in multiple inflammatory diseases. Controlling &#946;2 integrin activation presents a viable approach for treating neutrophil-associated inflammatory diseases. In this protocol, a monoclonal antibody, mAb24, which specifically binds to the high-affinity headpiece of &#946;2 integrins, is utilized to quantify &#946;2 integrin activation on isolated primary human neutrophils. N-formylmethionyl-leucyl-phenylalanine (fMLP) is used as a stimulus to activate neutrophil &#946;2 integrins. A high-throughput flow cytometer capable of automatically running 384-well plate samples was used in this study. The effects of 320 chemicals on &#946;2 integrin inhibition are assessed within 3 h. Molecules that directly target &#946;2 integrins or target molecules in the G protein-coupled receptor-initiated integrin inside-out activation signaling pathway can be identified through this approach.

This protocol describes a flow cytometry-based, high-throughput screening method to identify small-molecule drugs that inhibit &#946;2 integrin activation on human neutrophils.