Yazarlar, uzman teknik yardım için Bay Luis F. Delgadillo'ya (Ohio Üniversitesi Kimya ve Biyomoleküler Mühendislik Bölümü), Bay Matthew H. Williams'a (Ohio Üniversitesi Kimya ve Biyomoleküler Mühendislik Bölümü) ve Dr. Filiberto Cedeno-Laurent'e (Brigham ve Kadın Hastanesi ve Harvard Tıp Fakültesi) teşekkür etmek istiyor. Yazarlar ayrıca 2011 Kış 2011 CHE 404/BME 504 ve Sonbahar 2012 CHE 4830/BME 5830 öğrencilerine (Ohio Üniversitesi Kimya ve Biyomoleküler Mühendislik ve Biyomedikal Mühendisliği Programı Bölümü) teknik tavsiye ve tartışma için teşekkür etmek istemeleridir. Bu çalışma Ulusal Bilim Vakfı (NSF) Büyük Araştırma Araçları hibesi CBET-1039869 (MMB), NSF CBET-1106118 (MMB), Dermatoloji Vakfı Araştırma Hibesi A050422 (SRB), Ulusal Sağlık Enstitüleri (NIH) NCI hibesi 1R15CA1618 tarafından desteklendi.30-01 (MMB), NIH Kirschstein-NRSA Doktora Sonrası Burs F32CA144219-01A1 (SRB), NIH/NCI R01CA173610 (CJD) ve NIH NCCAM hibe R01AT004628 (CJD).

1. Protein A'nın Benzeşimini Doğrulayın
<ol><li>Fc ekspresyon proteininin (rekombinant füzyon proteini veya IgG antikoru, heretofore olarak adlandırılan "protein"), A membran adsorber proteinini kullanmadan önce A14-17 proteini için kabul edilebilir bir yakınlığa sahiptir ve proteinin stok çözeltisinde varlığını test edin(örneğin, 5 dakikalık pelet askıya alınmış hücreler için 1.000 x g'da santrifüjleme ile netleştirilmiş hücre kültürü süpernatantı). Akış sitometrisi, Batı şişkinliği, ELISA vb. laboratuvar tercihine göre protein fonksiyonunu ve/veya Fc varlığını tespit etmek. İdeal olarak, protein A membran adsorber kapasitesini aşmamak için hücre kültürü süpernatantındaki proteini ölçün (adım 6). Protein tespit edilirse devam edin.</li>
</ol>2. Protein A Membran Adsorber ve Hücre Kültürü Supernatant hazırlayın
<ol><li>Membran adsorberini hazırlamak için üreticinin talimatlarını izleyin. Havanın membran adsorber'e girmesine asla izin vermeyin. Membran adsorberden perfüzyona uğramış tüm çözeltiler oda sıcaklığında olmalı ve 0,22 μm filtre kullanılarak önceden filtrelenmelidir. 10 ml'lik bir şırınnayı 0,22 μm filtreli Dulbecco'nun fosfat tamponlu salin (DPBS) veya tercih edilen tampon ve deşarj hava kabarcıkları ile doldurun. Depolama çözeltisini çıkarmak ve kullanımdan hemen önce membran adsorberini aşındırmak için DPBS'yi kullanın.</li>
	<li>Vakumla yönlendirilen 0,22 μm steril filtrasyon ünitesi kullanarak hücre kültürü üstnatantını membran adsorberi aracılığıyla perfüzyondan hemen önce filtreleyin.</li>
</ol>3. Protein A Membran Adsorberini Yükleyin
<ol><li>Hücre kültürünü bir Luer Lock şırındına (30 ml veya daha büyük) apire edin ve hava kabarcıklarını boşaltın.</li>
	<li>Şekil 1'degösterildiği gibi malzeme ve ekipmanları birleştirin. Şırındırı membran adsorberinin girişine bağlayın. Membran adsorber çıkışına esnek boru takın. İsterseniz, şırınna ve membran adsorber arasına 0,22 μm şırınna filtresi yerleştirin. Adsorberden gelen akışı (filtrat olarak da bilinir) yakalamak için bir şişe veya şişe kullanın.</li>
	<li>Şırıng pompasını istediğiniz hacimsel akış hızına ayarlayın, ancak üreticinin önerilen akış hızını(örneğin 10 ml/dk) aşmayın. Hücre kültürünü membran adsorberi ile aşırıya uçurun, bir beherde veya başka bir kapta akış toplayın. Şırınnayı ihtiyaç duyulan süpernatantlarla yeniden yükleyin.</li>
	<li>İsterseniz, akış sitometrisi, Batı şişkinliği, ELISA vb. laboratuvar tercihe göre. Akışı yeniden gözden geçirmek genellikle gereksizdir.</li>
</ol>4. Membran Adsorberinden Elute Proteini
<ol><li>İlişkisiz proteinleri çıkarmak için membran adsorberini 10 ml DPBS ile yıkayın.</li>
	<li>Membran adsorberinden istenen akış hızında(örneğin 1 ml/dk) 10-15 ml elüasyon tamponu(örneğin amin bazlı elüasyon tamponu (pH 2.8)) kullanarak sıvı proteini. Nötralize edici tampon içeren bir tüpte(örneğin, 1 M Tris (pH 9.4)) elüasyon hacminin % 10'unda (1.0-1.5 ml) elüat yakalayın.</li>
	<li>Alternatif olarak, toplam 10-15 ml elüasyon tamponu hacmi kullanarak, bir ml'lik elüte proteini 100 μl nötralizasyon tamponu içeren tüplere indirir. Her kesir protein varlığını test etmek için tercih edilen karakterizasyon yöntemini kullanın.</li>
	<li>Membran adsorberini üreticinin talimatlarına göre yenilenin. 10 ml 0,22 μm filtreli DPBS veya tercih edilen tampon, daha sonra 1 N NaCl'de 10 ml 0,22 μm filtreli 50 mM NaOH ve son olarak 10 ml 0,22 μm filtreli DPBS. 4 ºC'de uzun süreli depolama için MEMB adsorberini DPBS'de% 20 etanol ile doldurun.</li>
</ol>5. Konsantre Olun ve Proteini Dialyze
<ol><li>Tüm eluatları (veya adım 4.3'te belirlenen protein içeren elüasyon fraksiyonlarını) 10 kDa moleküler ağırlık kesme santrifüj filtre ünitesinde biriktirin. Santrifüjleme için üreticinin talimatlarını izleyin.</li>
	<li>Üreticinin talimatlarına uyarak, retentate'i tercih edilen tampona karşı küçük hacimli bir diyaliz ünitesinde (10 kDa moleküler ağırlık kesme) dialyze edin. Protein çökeltme bir endişe ise, diyalze malzemeye tampon eklenmesi gerekebilir. İstenirse, diyalizlenmiş malzeme 6.</li>
</ol>6. Hızlandırılmış Batı Blotting Prosedüründe Saflaştırılmış Ürünü Ölçün ve Karakterize Edin
<ol><li>SDS-PAGE tarafından tercih edilen jeldeki saflaştırılmış protein ve Fc standartlarını, istenen18-20gibi azaltıcı veya tahriş edici olmayan koşullar altında çözün. Çalışma süresini en aza indirmek için midi jel yerine mini jel kullanın.<ol>
<li>Henüz bilinmiyorsa, bant sinyalinin yüklenen miktara göre doğrusal olarak değiştiği Fc standartları aralığını belirleyin(örneğin 0,1-1 mg). Saflaştırılmış proteini ölçmek ve karakterize etmek için kullanılacak aynı jeli, çalışma koşullarını, transfer koşullarını ve reaktifleri kullanın.</li>
			<li>Saflaştırılmış protein bandı sinyallerinin görüntü analizinde Fc standartlarının doğrusal sinyal aralığında olduğundan emin olmak için DPBS ile seyreltilmiş numuneler de dahil olmak üzere birden fazla numune miktarı saflaştırılmış protein yükleyin.</li>
		</ol>
</li>
	<li>Proteinleri jelden bir polivinliden florür (PVDF) membranına semidry blotter13kullanarak, leke üreticisinin talimatlarını izleyerek aktarın. Transfer süresi genellikle 5-10 dakikadır. İstenirse, Coomassie transfer verimliliğini doğrulamak için transferden sonra jeli lekeler21.</li>
	<li>Vakum destekli protein algılama sistemi kullanarak laboratuvar tercihine göre alkalin fosfataz (AP) veya at turpu peroksidazına (HRP) konjuge edilmiş anti-Fc veya anti-IgG ile immünblotting gerçekleştirin. İmmünblotting süresi genellikle 1 saatten azdır.</li>
	<li>Substratı ve tercih edilen yöntemi kullanarak immünoblot geliştirin(örneğin AP substratı ve gelişmiş kemimuminesans).</li>
	<li>Görüntü analizi ile saflaştırılmış proteini ölçün. Fc standartlarından gelen bant sinyallerinde doğrusal bir gerileme gerçekleştirin. R2>0,90 ise, bant sinyallerinden protein miktarını hesaplamak için çizginin denklemini kullanın. Gerekirse örnek seyreltme için hesap. Proteinin nicelemesi Fc temelinde gerçekleştirildiği için, protein ve Fc arasındaki moleküler ağırlık farklılıklarının değerini ayarlayın<.</li>
	<li>Akış sitometrisi, Batı şişkinliği, ELISA, vb. laboratuvar tercihe göre.</li>
	<li>Proteini istenen konsantrasyona seyreltin ve/veya uzun süreli depolama için aliquoting yapmadan önce, dondurulmuş veya başka bir şekilde saflaştırılmış protein çözeltisine istenen koruyucuları veya stabilizatörleri ekleyin.</li>
</ol>

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Açıklayacak bir şey yok.

Burada açıklanan protokol, ürün geri kazanımını veya şişirme maliyetini önemli ölçüde tehlikeye atmadan, insan Fc'yi (Gal-1hFc) ifade eden bir kimerik füzyon proteinini hızla izole etmek ve karakterize etmek için geliştirilmiştir. Aerodinamik iş akışının temel bileşenleri, izolasyon için bir protein A membran adsorber ve Batı şişkinliği ile karakterize için semidry transferi ve vakum destekli immünobotting'dir.
Gal-1hFc'nin 300 ml hücre kültürü süpernatant?...

Hücre kültürü süpernatantlarından ve seyreltilmiş lir hücre çözeltilerinden immünoglobulin G (IgG) Fc parçalarını ifade eden antikorların ve rekombinant proteinlerin izolasyonu protein A benzeşim kromatografisi kullanılarak gerçekleştirilebilir. Temel bilim ve mühendislik laboratuvarlarında ve endüstrisinde, gözenekli protein A kaplı agarose, cam veya polimerik boncuklarla dolu sütunlar, yüksek finansal maliyetlere ve uzun işlem sürelerine rağmen, benzeşim kromatografisi için en yaygın olarak1-3kullanılır. Benzeşim kromatografisinin hem laboratuvar hem de endüstriyel ortamlardaki en büyük gider ve işleme darboğazını temsil ettiği iyi takdir edilir2,4. Sonuç olarak, proses treni1,2,5-7'dengenel ürün geri kazanımından ödün vermeden maliyet ve işlem süresini azaltmak için çok sayıda iyileştirme geliştirilmiştir. Antikorların ve diğer Fc ekspresyon proteinlerinin izolasyonu için özellikle umut verici olan, A membran adsorber2,5,7-10proteini kullanılarak benzeşim kromatografisidir. Kolon kromatografisinde FC yakalaması difüzyon sınırlıyken(yani Fc ekspresyon proteini, protein A'nın çoğunluğuna ulaşmak için iç gözeneklere ve a yoluyla dağılmalı) sütun boyunca yüksek basınç düşüşü ile, membran adsorberlerindeki kütle taşımacılığı toplu konveksiyon ile yönlendirilir ve bu da difüzyon sınırlamalarından kaçınmaya neden olur8,9,11,12. Ek olarak, membran adsorber boyunca basınç düşüşü düşüktür, böylece boncuk dolu sütunlara kıyasla daha hızlı perfüzyon akış hızlarına izin verir8,9,11,12. Böylece laboratuvar ölçeği izolasyonu için membran kromatografinin izolasyon süresini birkaç saat azaltarak kolon kromatografisine göre ürün yakalamayı artıracağı öngörülür. Ayrıca, membran adsorberlerinde IgG adsorpsiyonu için matematiksel modeller önerilmiştir8,9,11,12, böylece son kullanıcıların laboratuvardaki performansı tahmin etmelerini sağlar.
Temel bilim ve mühendislik laboratuvarlarındaki bir diğer darboğaz, Fc ekspresyasyon proteininin karakterizasyonudur. Bununla birlikte, Batı lekeleri gibi karakterizasyon testlerini tamamlamak için uygun yöntemlerin seçilmesi, ürün testlerine harcanan zamanı büyük ölçüde azaltabilir. Örneğin, süreksiz bir tampon sisteminde semidry transferi, sürekli bir tampon sisteminde 1-2 saat tank (ıslak) transferinin aksine, proteinlerin bir SDS-PAGE jelinden polivinil difluoridin (PVDF) membrana elektroforetik transferini birkaç dakika içinde gerçekleştirebilir13.
İnsan IgG'nin fc parçasını ifade eden bir kimerik füzyon proteinini izole etmek ve karakterize etmek için hızlı, ucuz ve etkili bir protokol burada açıklanmıştır. Çoğu ekipman standart temel biyomedikal bilim, biyoloji, kimya ve (biyo)kimya mühendisliği laboratuvarlarında mevcuttur ve tüm reaktifler ticari olarak mevcuttur. Bir murine galektin-1/insan Fc chimeric füzyon proteininin (Gal-1hFc) izolasyonundan ve karakterizasyonundan temsili sonuçlar elde edilmiş olsa da, aerodinamik protokol antikorlar, Fc parçaları veya diğer Fc füzyon proteinleri gibi fc parçasına sahip diğer moleküllerin izolasyonuna uygulanabilir. Geliştirmelerimiz, standart yöntemlere kıyasla benzer veya geliştirilmiş ürün geri kazanımı elde ederken işlem süresini önemli ölçüde azalttı (4 saat kadar az ancak daha tipik olarak ~9 saat, 20+ çalışma saatine kıyasla).

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		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:313px;">Protein A membrane adsorber (Sartobind Protein A 2 ml)&#160;</td>
			<td style="width:191px;">Sartorius-Stedim</td>
			<td style="width:147px;">93PRAP06HB-12--A</td>
			<td style="width:173px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">Amicon Ultra centrifugal filter, 10 kDa, 4 ml</td>
			<td style="width:191px;">Millipore</td>
			<td>UFC801008</td>
			<td>Use 15 ml volume if needed</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">Sterile vacuum filter unit, 0.22 &#181;m, 500 ml</td>
			<td>Millipore</td>
			<td>SCGPU05RE</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">10 ml Syringes with Luer Lock tips</td>
			<td>BD</td>
			<td>301604</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">30 ml Syringes with&#160; Luer Lock tips</td>
			<td>BD</td>
			<td>309650</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">Tygon lab tubing (1/16 in x 1/8 in x 50 ft)</td>
			<td>Cole Parmer</td>
			<td>WU-95903-16</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:313px;">Slide-A-Lyzer MINI Dialysis Devices (10K MWCO)</td>
			<td>Thermo Scientific</td>
			<td>69576</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">Snap i.d. antibody collection tray</td>
			<td>EMD Millipore</td>
			<td>WBAVDABTR</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">Snap i.d. single well blot holder</td>
			<td>EMD Millipore</td>
			<td>WBAVDBH01</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">Elution buffer</td>
			<td>Thermo Scientific</td>
			<td>21004</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">Tris, ultra pure</td>
			<td>Fisher Scientific</td>
			<td>819623</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">Sodium chloride</td>
			<td>Fisher Scientific</td>
			<td>7647-14-5</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">Tween 20</td>
			<td>Fisher Scientific</td>
			<td>BP337-100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">DPBS</td>
			<td>Thermo Scientific&#160;</td>
			<td>SH30028.02</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:313px;">DPBS with Ca2+/Mg2+</td>
			<td>Life Technologies</td>
			<td>14080-055</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">BSA</td>
			<td>Sigma</td>
			<td>A9647</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">Human Fc</td>
			<td>Bethyl Research Laboratories</td>
			<td>&#160;P80-104</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">Anti-human Fc-APC</td>
			<td>Jackson Immunoresearch</td>
			<td>109136170</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">Anti-human Fc-AP</td>
			<td>Bio-Rad</td>
			<td>170-5018</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">Alkaline phosphatase substrate</td>
			<td>Promega</td>
			<td style="width:147px;">S3841</td>
			<td style="width:173px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:313px;">Flow cytometry tubes (5 ml polystyrene or polypropylene)</td>
			<td>BD</td>
			<td>352054</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;"></td>
			<td style="width:191px;"></td>
			<td style="width:147px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:313px;">Name of Material/ Equipment</td>
			<td style="width:191px;">Company</td>
			<td style="width:147px;">Catalog Number</td>
			<td>Comments/Description</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Syringe pump</td>
			<td>Harvard Apparatus</td>
			<td>55-2226</td>
			<td style="width:173px;">A peristaltic pump is also acceptable</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;">Protein gel electrophoresis system&#160;</td>
			<td>Bio-Rad Laboratories</td>
			<td>552BR094876</td>
			<td style="width:173px;">Any gel electrophoresis system is acceptable, but mini gel systems run fastest</td>
		</tr>
		<tr height="126">
			<td height="126" style="height:126px;">Semidry blotter&#160;</td>
			<td>Bio-Rad Laboratories</td>
			<td style="width:147px;">690BR006163</td>
			<td style="width:173px;">Any transfer system is acceptable, but discontinuos transfer systems perform electrophoretic transfer fastest</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:313px;">SNAP i.d. vacuum-assisted protein detection system</td>
			<td style="width:191px;">EMD Millipore</td>
			<td>WBAVDBASE</td>
			<td style="width:173px;">An upgraded model has replaced this specific instrument, but either should work just as well</td>
		</tr>
	</tbody>
</table>

isolation and characterization of chimeric human fc-expressing proteins using protein a membrane adsorbers and a streamlined workflow

Biyomoleküllerin hücre kültüründen endüstriyel ölçekte arındırılması için laboratuvar ölçeğinde süpernatantlar ve lisli hücre çözümleri benzeşim kromatografisi kullanılarak gerçekleştirilebilir. Gözenekli protein kullanılarak benzeşim kromatografisi Sütunlar halinde paketlenmiş agarose boncukları, IgG'nin Fc parçalarını ifade eden antikorların ve rekombinant proteinlerin laboratuvar ölçeği izolasyonunun tartışmasız en yaygın yöntemi olsa da, zaman alıcı ve pahalı bir süreç olabilir. Zaman ve finansal kısıtlamalar, özellikle seyreltilmiş çözeltilerden yüzlerce mikrogram ila miligram proteini geri kurtarması gereken, ancak yüksek basınçlı sıvı dağıtım sistemlerine ve / veya biyobenzerlik konusunda uzman personele erişimi olmayan küçük temel bilim laboratuvarlarında göz korkutucudur. Ayrıca, ürün nicelemesi ve karakterizasyonu da birkaç iş günü boyunca işlem süresini aşırı uzatabilir ve giderleri (sarf malzemeleri, ücretler vb.)şişirebilir. Bu nedenle, bir Fc parçasına sahip antikorların ve diğer proteinlerin laboratuvar ölçeği izolasyonu ve karakterizasyonu için hızlı, ucuz, ancak etkili bir protokol gereklidir. Bu amaçla, 20' den fazla çalışma saati gerektiren geleneksel yöntemlerin aksine, sınırlı deneyime sahip teknik personel tarafından 9 saatten daha kısa bir sürede (kabaca bir iş günü) ve 4 saat kadar hızlı bir şekilde tamamlanabilen bir protokol tasarladık. Gerekli ekipmanların çoğu standart biyomedikal bilim, biyokimya ve (biyo)kimya mühendisliği laboratuvarlarında mevcuttur ve tüm reaktifler ticari olarak mevcuttur. Bu protokolü göstermek için, hücre kültürü üstnatantından insan Fc'ye (Gal-1hFc) kaynaşmış kimerik murine galectin-1'in A membran adsorber proteini kullanılarak izole edildiği temsili sonuçlar sunulmaktadır. Saflaştırılmış Gal-1hFc hızlandırılmış bir Batı blotting analiz prosedürü kullanılarak ölçüldü ve akış sitometrisi kullanılarak karakterize edildi. Kolaylaştırılmış iş akışı, antikorlar gibi diğer Fc ekspresyel proteinleri için değiştirilebilir ve/veya alternatif niceleme ve karakterizasyon yöntemlerini içerecek şekilde değiştirilebilir.

Fc ekspresyon proteinlerinin izolasyonu ve karakterizasyonu için kolaylaştırılmış protokol, insan Fc 'ye (Gal-1hFc) kaynaşmış kimerik murine galektin-1'i seyreltik hücre kültürü süpernatantlarından işlemek için rutin olarak kullanılır. Şekil 2'deki akış çizelgesi, protokoldeki her adım için iş akışını ve zamanı gösterir. Tipik bir 300 ml'lik süpernatant grubu için, elütion fraksiyonlarının isteğe bağlı akış sitometrisi testi gerçekleştirildiğinde toplam işlem...

Watch this Scientific Journal Video about Isolation and Characterization Of Chimeric Human Fc-expressing Proteins Using Protein A Membrane Adsorbers And A Streamlined Workflow at JoVE.com

Isolation and Characterization Of Chimeric Human Fc-expressing Proteins Using Protein A Membrane Adsorbers And A Streamlined Workflow

Protein A agarose boncuk dolu sütunlar kullanılarak geleneksel benzeşim kromatografisi ile karşılaştırıldığında, protein A membran adsorberleri antikorların ve diğer Fc parça ifade eden proteinlerin laboratuvar ölçeğinde izolasyonunu önemli ölçüde hızlandırabilir. Uygun analiz ve niceleme yöntemleri protein işlemeyi daha da hızlandırarak izolasyonun/karakterizasyonun 20+ iş saati yerine tek bir iş gününde tamamlanmasını sağlayabilir.

Protein A Membran Adsorberleri ve Kolaylaştırılmış bir İş Akışı Kullanarak Kimerik İnsan Fc Ekspresyon Proteinlerinin İzolasyonu ve Karakterizasyonu

Laboratory scale to industrial scale purification of biomolecules from cell culture supernatants and lysed cell solutions can be accomplished using ...

isolation-characterization-chimeric-human-fc-expressing-proteins

Research

JoVE Journal

Bioengineering

7.1K Görüntüleme.  Ohio University. Protein A agarose boncuk dolu sütunlar kullanılarak geleneksel benzeşim kromatografisi ile karşılaştırıldığında, protein A membran adsorberleri antikorların ve diğer Fc parça ifade eden proteinlerin laboratuvar ölçeğinde izolasyonunu önemli ölçüde hızlandırabilir. Uygun analiz ve niceleme yöntemleri protein işlemeyi daha da hızlandırarak izolasyonun/karakterizasyonun 20+ iş saati yerine tek bir iş gününde tamamlanmasını sağlayabilir.

Video: Isolation and Characterization Of Chimeric Human Fc-expressing Proteins Using Protein A Membrane Adsorbers And A Streamlined Workflow

Creating Two-Dimensional Patterned Substrates for Protein and Cell Confinement

Microcontact printing provides a rapid, highly reproducible method for the creation of well-defined patterned substrates.1 While microcontact printing can be employed to directly print a large number of molecules, including proteins,2 DNA,3 and silanes,4 the formation of self-assembled monolayers (SAMs) from long chain alkane thiols on gold provides a simple way to confine proteins and cells to specific patterns containing adhesive and resistant regions. This confinement can be used to control cell morphology and is useful for examining a variety of questions in protein and cell biology. Here, we describe a general method for the creation of well-defined protein patterns for cellular studies.5 This process involves three steps: the production of a patterned master using photolithography, the creation of a PDMS stamp, and microcontact printing of a gold-coated substrate. Once patterned, these cell culture substrates are capable of confining proteins and/or cells (primary cells or cell lines) to the pattern.
The use of self-assembled monolayer chemistry allows for precise control over the patterned protein/cell adhesive regions and non-adhesive regions; this cannot be achieved using direct protein stamping. Hexadecanethiol, the long chain alkane thiol used in the microcontact printing step, produces a hydrophobic surface that readily adsorbs protein from solution. The glycol-terminated thiol, used for backfilling the non-printed regions of the substrate, creates a monolayer that is resistant to protein adsorption and therefore cell growth.6 These thiol monomers produce highly structured monolayers that precisely define regions of the substrate that can support protein adsorption and cell growth. As a result, these substrates are useful for a wide variety of applications from the study of intercellular behavior7 to the creation of microelectronics.8
While other types of monolayer chemistry have been used for cell culture studies, including work from our group using trichlorosilanes to create patterns directly on glass substrates,9 patterned monolayers formed from alkane thiols on gold are straight-forward to prepare. Moreover, the monomers used for monolayer preparation are commercially available, stable, and do not require storage or handling under inert atmosphere. Patterned substrates prepared from alkane thiols can also be recycled and reused several times, maintaining cell confinement.10

Self-assembled monolayers (SAMs) formed from long chain alkane thiols on gold provide well-defined substrates for the formation of protein patterns and cell confinement. Microcontact printing of hexadecanethiol using a polydimethylsiloxane (PDMS) stamp followed by backfilling with a glycol-terminated alkane thiol monomer produces a pattern where protein and cells adsorb only to the stamped hexadecanethiol region.

Protein ve hücre Etrafının İki Boyutlu Desenli Yüzeyler Oluşturma

Microcontact printing provides a rapid, highly reproducible method for the creation of well-defined patterned substrates.1  While microcontact printing ...

Biyomühendislik

Detection and Isolation of Circulating Melanoma Cells using Photoacoustic Flowmetry

Circulating tumor cells (CTCs) are those cells that have separated from a macroscopic tumor and spread through the blood and lymph systems to seed secondary tumors1,2,3. CTCs are indicators of metastatic disease and their detection in blood samples may be used to diagnose cancer and monitor a patient&prime;s response to therapy. Since CTCs are rare, comprising about one tumor cell among billions of normal blood cells in advanced cancer patients, their detection and enumeration is a difficult task. We exploit the presence of pigment in most melanoma cells to generate photoacoustic, or laser induced ultrasonic waves in a custom flow cytometer for detection of circulating melanoma cells (CMCs)4,5. This process entails separating a whole blood sample using centrifugation and obtaining the white blood cell layer. If present in whole blood, CMCs will separate with the white blood cells due to similar density. These cells are resuspended in phosphate buffered saline (PBS) and introduced into the flowmeter. Rather than a continuous flow of the blood cell suspension, we induced two phase flow in order to capture these cells for further study. In two phase flow, two immiscible liquids in a microfluidic system meet at a junction and form alternating slugs of liquid6,7. PBS suspended white blood cells and air form microliter slugs that are sequentially irradiated with laser light. The addition of a surfactant to the liquid phase allows uniform slug formation and the user can create different sized slugs by altering the flow rates of the two phases. Slugs of air and slugs of PBS with white blood cells contain no light absorbers and hence, do not produce photoacoustic waves. However, slugs of white blood cells that contain even single CMCs absorb laser light and produce high frequency acoustic waves. These slugs that generate photoacoustic waves are sequestered and collected for cytochemical staining for verification of CMCs.

We have developed a flow cytometer using laser induced ultrasound to detect circulating melanoma cells as an early indicator of metastatic disease.

Sirkülasyon Melanom Hücreler foto akustik flowmetre kullanarak Algılama ve İzolasyonu

Circulating tumor cells (CTCs) are those cells that have separated from a macroscopic tumor and spread through the blood and lymph systems to seed ...

Membrane-SPINE: A Biochemical Tool to Identify Protein-protein Interactions of Membrane Proteins In Vivo

Membrane proteins are essential for cell viability and are therefore important therapeutic targets1-3. Since they function in complexes4, methods to identify and characterize their interactions are necessary5. To this end, we developed the Membrane Strep-protein interaction experiment, called Membrane-SPINE6. This technique combines in vivo cross-linking using the reversible cross-linker formaldehyde with affinity purification of a Strep-tagged membrane bait protein. During the procedure, cross-linked prey proteins are co-purified with the membrane bait protein and subsequently separated by boiling. Hence, two major tasks can be executed when analyzing protein-protein interactions (PPIs) of membrane proteins using Membrane-SPINE: first, the confirmation of a proposed interaction partner by immunoblotting, and second, the identification of new interaction partners by mass spectrometry analysis. Moreover, even low affinity, transient PPIs are detectable by this technique. Finally, Membrane-SPINE is adaptable to almost any cell type, making it applicable as a powerful screening tool to identify PPIs of membrane proteins.

Membrane-SPINE: A Biochemical Tool to Identify Protein-protein Interactions of Membrane Proteins In Vivo

A biochemical approach is described to identify in vivo protein-protein interactions (PPI) of membrane proteins. The method combines protein cross-linking, affinity purification and mass spectrometry, and is adaptable to almost any cell type or organism. With this approach, even the identification of transient PPIs becomes possible.

Membran-OMURGA: Membran Proteinleri protein-protein etkileşimleri belirlemek için bir Biyokimyasal Aracı<em&gt; In Vivo</em

Membrane proteins are essential for cell viability and are therefore important therapeutic targets1-3. Since they function in complexes4, methods to ...

Synthesis of an Intein-mediated Artificial Protein Hydrogel

We present the synthesis of a highly stable protein hydrogel mediated by a split-intein-catalyzed protein trans-splicing reaction. The building blocks of this hydrogel are two protein block-copolymers each containing a subunit of a trimeric protein that serves as a crosslinker and one half of a split intein. A highly hydrophilic random coil is inserted into one of the block-copolymers for water retention. Mixing of the two protein block copolymers triggers an intein trans-splicing reaction, yielding a polypeptide unit with crosslinkers at either end that rapidly self-assembles into a hydrogel. This hydrogel is very stable under both acidic and basic conditions, at temperatures up to 50 &#176;C, and in organic solvents. The hydrogel rapidly reforms after shear-induced rupture. Incorporation of a &#34;docking station peptide&#34; into the hydrogel building block enables convenient incorporation of &#34;docking protein&#34;-tagged target proteins. The hydrogel is compatible with tissue culture growth media, supports the diffusion of 20 kDa molecules, and enables the immobilization of bioactive globular proteins. The application of the intein-mediated protein hydrogel as an organic-solvent-compatible biocatalyst was demonstrated by encapsulating the horseradish peroxidase enzyme and corroborating its activity.

We present the synthesis of a split-intein-mediated protein hydrogel. The building blocks of this hydrogel are two protein copolymers each containing a subunit of a trimeric protein that serves as a crosslinker and one half of a split intein. Mixing of the two protein copolymers triggers an intein trans-splicing reaction, yielding a polypeptide unit that self-assembles into a hydrogel. This hydrogel is highly pH- and temperature-stable, compatible with organic solvents, and easily incorporates functional globular proteins.

Bir Intein aracılı yapay protein Hidrojel sentezi

We present the synthesis of a highly stable protein hydrogel mediated by a split-intein-catalyzed protein trans-splicing reaction. The building blocks of ...

Characterization of Complex Systems Using the Design of Experiments Approach: Transient Protein Expression in Tobacco as a Case Study

Plants provide multiple benefits for the production of biopharmaceuticals including low costs, scalability, and safety. Transient expression offers the additional advantage of short development and production times, but expression levels can vary significantly between batches thus giving rise to regulatory concerns in the context of good manufacturing practice. We used a design of experiments (DoE) approach to determine the impact of major factors such as regulatory elements in the expression construct, plant growth and development parameters, and the incubation conditions during expression, on the variability of expression between batches. We tested plants expressing a model anti-HIV monoclonal antibody (2G12) and a fluorescent marker protein (DsRed). We discuss the rationale for selecting certain properties of the model and identify its potential limitations. The general approach can easily be transferred to other problems because the principles of the model are broadly applicable: knowledge-based parameter selection, complexity reduction by splitting the initial problem into smaller modules, software-guided setup of optimal experiment combinations and step-wise design augmentation. Therefore, the methodology is not only useful for characterizing protein expression in plants but also for the investigation of other complex systems lacking a mechanistic description. The predictive equations describing the interconnectivity between parameters can be used to establish mechanistic models for other complex systems.

We describe a design of experiments approach that can be used to determine and model the influence of transgene regulatory elements, plant growth and development parameters, and incubation conditions on the transient expression of monoclonal antibodies and reporter proteins in plants.

Bir Vaka Çalışması Olarak Tütün Geçici Protein Expression: Deneyler Yaklaşımı Tasarım Kullanma Karmaşık Sistemler Karakterizasyonu

Plants provide multiple benefits for the production of biopharmaceuticals including low costs, scalability, and safety. Transient expression offers the ...

Expression, Isolation, and Purification of Soluble and Insoluble Biotinylated Proteins for Nerve Tissue Regeneration

Recombinant protein engineering has utilized Escherichia coli (E. coli) expression systems for nearly 4 decades, and today E. coli is still the most widely used host organism. The flexibility of the system allows for the addition of moieties such as a biotin tag (for streptavidin interactions) and larger functional proteins like green fluorescent protein or cherry red protein. Also, the integration of unnatural amino acids like metal ion chelators, uniquely reactive functional groups, spectroscopic probes, and molecules imparting post-translational modifications has enabled better manipulation of protein properties and functionalities. As a result this technique creates customizable fusion proteins that offer significant utility for various fields of research. More specifically, the biotinylatable protein sequence has been incorporated into many target proteins because of the high affinity interaction between biotin with avidin and streptavidin. This addition has aided in enhancing detection and purification of tagged proteins as well as opening the way for secondary applications such as cell sorting. Thus, biotin-labeled molecules show an increasing and widespread influence in bioindustrial and biomedical fields. For the purpose of our research we have engineered recombinant biotinylated fusion proteins containing nerve growth factor (NGF) and semaphorin3A (Sema3A) functional regions. We have reported previously how these biotinylated fusion proteins, along with other active protein sequences, can be tethered to biomaterials for tissue engineering and regenerative purposes. This protocol outlines the basics of engineering biotinylatable proteins at the milligram scale, utilizing&#160; a T7 lac inducible vector and E. coli expression hosts, starting from transformation to scale-up and purification.

Developing biotinylatable fusion proteins has many potential applications in various fields of research. Recombinant protein engineering is a straight forward procedure that is cost-effective, providing high yields of custom-designed proteins.

Sinir doku rejenerasyonu için Çözünür ve Çözünmeyen Biyotinile Proteinlerin ifade, izolasyon ve saflaştırılması

Recombinant protein engineering has utilized Escherichia coli (E. coli) expression systems for nearly 4 decades, and today E. coli is still the most ...

Luminescence Resonance Energy Transfer to Study Conformational Changes in Membrane Proteins Expressed in Mammalian Cells

Luminescence Resonance Energy Transfer, or LRET, is a powerful technique used to measure distances between two sites in proteins within the distance range of 10-100 &#197;. By measuring the distances under various ligated conditions, conformational changes of the protein can be easily assessed. With LRET, a lanthanide, most often chelated terbium, is used as the donor fluorophore, affording advantages such as a longer donor-only emission lifetime, the flexibility to use multiple acceptor fluorophores, and the opportunity to detect sensitized acceptor emission as an easy way to measure energy transfer without the risk of also detecting donor-only signal. Here, we describe a method to use LRET on membrane proteins expressed and assayed on the surface of intact mammalian cells. We introduce a protease cleavage site between the LRET fluorophore pair. After obtaining the original LRET signal, cleavage at that site removes the specific LRET signal from the protein of interest allowing us to quantitatively subtract the background signal that remains after cleavage. This method allows for more physiologically relevant measurements to be made without the need for purification of protein.

We describe here an improved Luminescence Resonance Energy Transfer (LRET) method where we introduce a protease cleavage site between the donor and acceptor fluorophore sites. This modification allows us to obtain specific LRET signals arising from membrane proteins of interest, allowing for the study of membrane proteins without protein purification.

Lüminesans Rezonans Enerji memeli hücrelerinde ifade Membran Proteinleri Konformasyonel Değişiklikleri Eğitim transfer

Luminescence Resonance Energy Transfer, or LRET, is a powerful technique used to measure distances between two sites in proteins within the distance range ...

Production, Characterization and Potential Uses of a 3D Tissue-engineered Human Esophageal Mucosal Model

The incidence of both esophageal adenocarcinoma and its precursor, Barrett&#8217;s Metaplasia, are rising rapidly in the western world. Furthermore esophageal adenocarcinoma generally has a poor prognosis, with little improvement in survival rates in recent years. These are difficult conditions to study and there has been a lack of suitable experimental platforms to investigate disorders of the esophageal mucosa.
A model of the human esophageal mucosa has been developed in the MacNeil laboratory which, unlike conventional 2D cell culture systems, recapitulates the cell-cell and cell-matrix interactions present in vivo and produces a mature, stratified epithelium similar to that of the normal human esophagus. Briefly, the model utilizes non-transformed normal primary human esophageal fibroblasts and epithelial cells grown within a porcine-derived acellular esophageal scaffold. Immunohistochemical characterization of this model by CK4, CK14, Ki67 and involucrin staining demonstrates appropriate recapitulation of the histology of the normal human esophageal mucosa.
This model provides a robust, biologically relevant experimental model of the human esophageal mucosa. It can easily be manipulated to investigate a number of research questions including the effectiveness of pharmacological agents and the impact of exposure to environmental factors such as alcohol, toxins, high temperature or gastro-esophageal refluxate components. The model also facilitates extended culture periods not achievable with conventional 2D cell culture, enabling, inter alia, the study of the impact of repeated exposure of a mature epithelium to the agent of interest for up to 20 days. Furthermore, a variety of cell lines, such as those derived from esophageal tumors or Barrett&#8217;s Metaplasia, can be incorporated into the model to investigate processes such as tumor invasion and drug responsiveness in a more biologically relevant environment.

This manuscript describes the production, characterization and potential uses of a tissue engineered 3D esophageal construct prepared from normal primary human esophageal fibroblast and squamous epithelial cells seeded within a de-cellularized porcine scaffold. The results demonstrate the formation of a mature stratified epithelium similar to the normal human esophagus.

3D Doku mühendisliği İnsan Özofagus Mukozal Modeli Üretimi, Karakterizasyonu ve Potansiyel Kullanımları

The incidence of both esophageal adenocarcinoma and its precursor, Barrett&#8217;s Metaplasia, are rising rapidly in the western world. Furthermore ...

Biomechanical Characterization of Human Soft Tissues Using Indentation and Tensile Testing

Regenerative medicine aims to engineer materials to replace or restore damaged or diseased organs. The mechanical properties of such materials should mimic the human tissues they are aiming to replace; to provide the required anatomical shape, the materials must be able to sustain the mechanical forces they will experience when implanted at the defect site. Although the mechanical properties of tissue-engineered scaffolds are of great importance, many human tissues that undergo restoration with engineered materials have not been fully biomechanically characterized. Several compressive and tensile protocols are reported for evaluating materials, but with large variability it is difficult to compare results between studies. Further complicating the studies is the often destructive nature of mechanical testing. Whilst an understanding of tissue failure is important, it is also important to have knowledge of the elastic and viscoelastic properties under more physiological loading conditions.
This report aims to provide a minimally destructive protocol to evaluate the compressive and tensile properties of human soft tissues. As examples of this technique, the tensile testing of skin and the compressive testing of cartilage are described. These protocols can also be directly applied to synthetic materials to ensure that the mechanical properties are similar to the native tissue. Protocols to assess the mechanical properties of human native tissue will allow a benchmark by which to create suitable tissue-engineered substitutes.

Tissue biomechanics is important for maintaining cell shape and function and for determining phenotype. This report demonstrates non-destructive mechanical protocols for characterizing elastic and viscoelastic properties of human soft tissues, which can be directly applied to tissue-engineered substrates to allow a close matching of engineered materials to native tissue.

Girinti ve Çekme Test Kullanarak İnsan Yumuşak Doku biyomekanik Karakterizasyonu

Regenerative medicine aims to engineer materials to replace or restore damaged or diseased organs. The mechanical properties of such materials should ...

Fabrication and Characterization of Optical Tissue Phantoms Containing Macrostructure

The rapid development of new optical imaging techniques is dependent on the availability of low-cost, customizable, and easily reproducible standards. By replicating the imaging environment, costly animal experiments to validate a technique may be circumvented. Predicting and optimizing the performance of in vivo and ex vivo imaging techniques requires testing on samples that are optically similar to tissues of interest. Tissue-mimicking optical phantoms provide a standard for evaluation, characterization, or calibration of an optical system. Homogenous polymer optical tissue phantoms are widely used to mimic the optical properties of a specific tissue type within a narrow spectral range. Layered tissues, such as the epidermis and dermis, can be mimicked by simply stacking these homogenous slab phantoms. However, many in vivo imaging techniques are applied to more spatially complex tissue where three dimensional structures, such as blood vessels, airways, or tissue defects, can affect the performance of the imaging system. 
This protocol describes the fabrication of a tissue-mimicking phantom that incorporates three-dimensional structural complexity using material with optical properties of tissue. Look-up tables provide India ink and titanium dioxide recipes for optical absorption and scattering targets. Methods to characterize and tune the material optical properties are described. The phantom fabrication detailed in this article has an internal branching mock airway void; however, the technique can be broadly applied to other tissue or organ structures.

Optical tissue phantoms are essential tools for calibration and characterization of optical imaging systems and validation of theoretical models. This article details a method for phantom fabrication that includes replication of tissue optical properties and three-dimensional tissue structure.

İmalat ve Macrostructure içeren optik doku hayaletler karakterizasyonu

The rapid development of new optical imaging techniques is dependent on the availability of low-cost, customizable, and easily reproducible standards. By ...