Name: cholesterol efflux assay
Uploaded: 2012-03-06T13:00:00.000+00:00
Duration: 7 min 54 s
Description: Watch this Scientific Journal Video about Cholesterol Efflux Assay at JoVE.com

Bu çalışma Victoria Hükümeti&#39;nin OIS Programı tarafından Ulusal Sağlık ve Avustralya Tıbbi Araştırma Konseyi (NHMRC) (526.615 ve 545.906) gelen ve kısmen hibe ile desteklenmiştir. DS NHMRC bir üyesidir.

1. [3H]-kolesterol hazırlanması <ol><li> Çeker ocak içinde bir 1.5 ml mikrofuj tüp (0,5 oyuk başına μCi (19 kBq) Tipik bir deney için gerekli olan) içine [3 H] kolesterol gerekli miktarda dağıtın. </li><li> [3H]-Kolesterol tolüen içinde süspansiyon haline getirildiği takdirde, 1 μCi bir son konsantrasyon% 100 etanol ile N2 gaz ve Pastör pipetiyle (de 37 kBq / ul. Vorteks ve karışım ile tamamen aşağı kurutun. </li></ol> 2. Kaplama Hücreler ve Etiketleme Hücresel kolesterol Insan monosit 4,5, THP-1 insan monosit-makrofajlar 6,7,8, RAW 264.7 murin makrofajlar 5,9,10,11, HeLa hücrelerinde 12, endotel insan umbilikal ven: Bu protokol, aşağıdaki hücre tipleri kullanılarak test edilmiştir trombositler hücreleri (HUVEC), BHK-21 hücreleri 9, insan ve fare fibroblastlar 13,14, HepG2 hücrelerinde insan hepatokarsinoma 15 ve modifiye formunda, &lt;&gt; 16 sup. <ol><li> Hücreleri yeniden süspanse edin ve onları saymak. 0.9 ml tam medyum içinde oyuk başına 6 0.2x10 hücre nihai yoğunlukta 12 oyuklu plakalar haline plakası hücreleri. Hücreler büyümeye devam edecek ve efflux deney zaman iyi başına 0.8x10 6 hücre ulaşacak. Gibi farklılaştırılmış THP-1 hücreleri gibi bölmek değil hücreler için, ekim yoğunluğu başına iyi 0.8x10 6 hücre olmalıdır. Sırasıyla veya 24 de plaka, çift ya da başına hücre sayısının yarısından - 6 kullanıyorsanız. Kuyu sayısı her deneysel koşul için dört nüsha tayini için yeterli olmalıdır. </li><li> THP-1 hücrelerinin farklılaşmasını gerekli ise, 48-72 saat boyunca ortam PMA (nihai konsantrasyon 0.1 ug / ml) ilave edilir. </li><li> [3H] kolesterol içeren mikrofüj tüpe ortam küçük bir alikotu ekleyin. </li><li> Tam kültür ortamı ayrı bir alikotu (100 ul / kuyucuk) içine [3H] kolesterol eklemeden önce ortamı ile iki tüpün yıkanır. </li> &lt;li&gt; hücreleri (çukur başına son hacim 1 ml) ile kuyucuklara [3 H] kolesterol içeren ortam ekleyin. Hücrelerinde hiçbir tedavi etiketlenmesi önce gerekli ise, hücreler [3 H] kolesterol içeren orta kaplama olabilir. </li><li> (37 ° C&#39;de,% 5 CO2) hücre kültürü inkübatöre 48 saat boyunca inkübe hücreleri. </li></ol> 3. Denge Kuluçka <ol><li> 48 saat inkübasyondan sonra, mikroskop altında hücrelerin kontrol edin. Sağlıklı oldukları ve yaklaşık% 80 izdiham olduğundan emin olun. </li><li> Ortam [3 H] kolesterol içeren çıkarın. PBS ile hafifçe hücreleri yıkayın. 3 yıkama kez tekrarlayın. </li><li> Serumsuz ortam hazırlayın. Serum serbest-medya; Gerekirse, LXR agonist (örneğin 1-4 mMol / L &#39;TO-901317 gibi) veya cAMP (sadece fare kökenli hücreler için 0.3 mmol / L) ekleyerek hücrelerini aktive eder. </li><li> Her kuyuya 500 mikrolitre serum serbest Medya ekle. </li><li> (37 ° C&#39;de,% 5 CO2) hücre kültürü inkübatöre 18 saat boyunca inkübe edilir. </li></ol> &lt;p class = &quot;jove_title&quot;&gt; 4. Kolesterol akışı Kuluçka <ol><li> Serum içermeyen aracı madde içinde 18 saatlik inkübasyondan sonra, mikroskop altında hücreleri kontrol. (En az% 80 konfluense) sağlıklı ve birleşik olduğundan emin olun. </li><li> Serum içermeyen aracı madde içinde kolesterol akışı alıcısının çözeltisi hazırlayın. Muhatapları örnekler: Apolipoprotein AI (apoA-I) (son konsantrasyonu 10 mg / ml) Yüksek dansiteli lipoprotein (HDL) (son konsantrasyonu 20 mg / ml) Siklodekstrin (nihai konsantrasyon 200 ug / ml) Plazma (son konsantrasyon% 1-2) </li><li> PBS ile hafifçe hücreleri yıkayın. </li><li> Her bir kuyuya muhatapları ile serumsuz medya 250 ul ekleyin. </li><li> Arka plan efflux (NO alıcı ile serum serbest medya efflux) belirlemek için kuyu bir takım bırakın </li><li> Hücre kültürü inkübatörde 2 saat boyunca hücreleri (37 ° C&#39;de,% 5 CO2) inkübe. Gerekirse efflux inkübasyon süresi 30 dakika ile 8 saat değişebilir. </li></ol> 5.. İşleme Samples <ol><li> 2 saat sonra kuluçka mikroskop altında hücrelerin kontrol edin. </li><li> 1.5 ml mikrofuge&#39;de tüpler içine medya toplayın. Hücresel enkaz kaldırmak için oda sıcaklığında 1-10 dakika 14.000 rpm&#39;de Spin. </li><li> 7 ml sintilasyon şişeye 100 ul medya aktarın. 5 Insta-jel Plus mls (Perkin Elmer) ve vorteks karışımı ekleyin. 4 ° C&#39;de geri kalan örnekleri depolamak </li><li> 30 dakika için dondurucuya plakaları yerleştirin. Her kuyucuğa 500 ul dH 2 O ekleyin. Tüm hücreleri kuyu dibinden kaldırdı emin olmak için mikroskop altında hücrelerin kontrol edin. Hala yapışık ise, 4 ° C de bir gece veya sıyrık kuyularında dH 2 O ile plakalar bırakın ya. </li><li> Tüm hücreler kaldırdı sonra, hücre kümeleri kırmak için aşağı ve yukarı Pipeti. 7 ml sintilasyon vial içine 100 ul aktarın. 5 Insta-jel Plus mls (Perkin Elmer) ve vorteks karışımı ekleyin. 4 ° C&#39;de geri kalan plakaları depolamak </li><li> Sintilasyon sayacı sintilasyon şişelerine yerleştirin. [3 H] için saymak için sayaç yapılandırındpm birimleri. </li></ol> 6. Sonuçları analiz <ol><li> Kolesterol akışı oranı, genellikle kolesterol bir oranda hücrelerinden alıcı taşınır olarak ifade edilir. Aşağıdaki formül kullanılır: </li></ol><img alt="Denklem 1" src="/files/ftp_upload/3810/3810eq1.jpg" /><ol start="2"><li> Belirli bir akış alıcı (boşluk) varlığında veya yokluğunda, akış arasındaki fark olarak hesaplanır. </li></ol><img alt="Denklem 2" src="/files/ftp_upload/3810/3810eq2.jpg" /> 7. Timeline <img alt="Şekil 1" src="/files/ftp_upload/3810/3810timeline.jpg" /> 8. Temsilcisi Sonuçlar Bir kolesterol akışı deneyde bir sonucu bir örneği, Şek. 1. Bu deneyde THP-1 insan monosit oldu farklı kabul eden makrofaj ve kolesterol akışı içine ayırtlanmıştırtest edilmiştir. Hiçbir alıcıları (&quot;boş&quot;) ile orta kolesterol akışı% 0.79 idi ve bu değer bir non-spesifik akış olarak kabul edilmiş ve diğer değerleri çıkarıldı. İnsan ApoA-I (nihai konsantrasyon 30 ug / ml) ile kolesterol akışı% 4.75 olmuştur. Bir başvuru plazma örneği arası deneysel değişkenlik izlemek için, bu deney dahil edildi. Bir referans örnek deney boyunca çok sayıda veri normalizasyon için kullanılır, ama değişkenliği yüksek olup olmadığını test tekrar bu ihtiyatlı bulunabilir. Hastanın ilacı ile muamele edilmiş, önce ve sonra bir hasta plazma (son konsantrasyon% 2) test edilmiştir. Bu hastada ilaç kolesterol akışı desteklemek için plazma kapasitesi üzerinde olumsuz etkilere sahip olduğu sonucuna varılmıştır. Efflux deneyde bir sonucu başka bir örneği şekil gösterilmektedir. 2. Bu deneyde RAW 264.7 makrofaj LXR agonisti TO-901.317 ile birlikte bir gece inkübasyon (son konsantrasyon ile aktive veya devreye alınmadı1 mmol / L) ve insan plazma aynı örnek (% 2) kolesterol akışı test edildi. Bu LXR agonisti ile ABC taşıyıcıları hücresel ifade aktivasyon ekstrasellüler alıcı için kolesterol serbest hücrelerinin kapasitesini artırır sonucuna varılmıştır. <img alt="Şekil 1" src="/files/ftp_upload/3810/3810fig1.jpg" /> Şekil 1.. Çeşitli alıcıları için THP-1 hücrelerinden kolesterol akışı. Kolesterol akışı yüzdesi (yani etiketli kolesterol oranı hücrelerinden belirtilen alıcı taşındı) boş değerler çıkarma sonra gösterilmiştir. Ortalama ± dörderli tayin SD, * p &lt;0.05. <img alt="Şekil 2" src="/files/ftp_upload/3810/3810fig2.jpg" /> Şekil 2. Kolesterol akışı RAW 264.7 insan plazma LXR agonisti ile aktif ya da aktif değil. Yüzde (yani etiketli kolesterol oranı ile kolesterol akışı hücrelerden taşındıbelirtilen alıcı) boş değerler çıkarma sonra gösterilmiştir. Ortalama ± dörderli tayin SD, * p &lt;0.001.

<ol>
	<li>Tabas, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cholesterol+in+health+and+disease.">Cholesterol in health and disease.</a> J. Clin. Invest. 110, 583-590 (2002).</li><li>Brown, M. S., Goldstein, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cholesterol+feedback:+from+Schoenheimer's+bottle+to+Scap's+MELADL.">Cholesterol feedback: from Schoenheimer's bottle to Scap's MELADL.</a> J. Lipid Res. 50, 15-27 (2009).</li><li>Tabas, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Consequences+of+cellular+cholesterol+accumulation:+basic+concepts+and+physiological+implications.">Consequences of cellular cholesterol accumulation: basic concepts and physiological implications.</a> J. Clin. Invest. 110, 905-911 (2002).</li><li>Murphy, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-Density+Lipoprotein+Reduces+the+Human+Monocyte+Inflammatory+Response.">High-Density Lipoprotein Reduces the Human Monocyte Inflammatory Response.</a> Arterioscler. Thromb. Vasc. Biol. 28, 2071-2077 (2008).</li><li>Mujawar, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+Immunodeficiency+Virus+Impairs+Reverse+Cholesterol+Transport+from+Macrophages.">Human Immunodeficiency Virus Impairs Reverse Cholesterol Transport from Macrophages.</a> PLoS Biology. 4, 365-36 (2006).</li><li>Patel, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reconstituted+High-Density+Lipoprotein+Increases+Plasma+High-Density+Lipoprotein+Anti-Inflammatory+Properties+and+Cholesterol+Efflux+Capacity+in+Patients+With+Type+2+Diabetes.">Reconstituted High-Density Lipoprotein Increases Plasma High-Density Lipoprotein Anti-Inflammatory Properties and Cholesterol Efflux Capacity in Patients With Type 2 Diabetes.</a> J. Am. Coll. Cardiol. 53, 962-971 (2009).</li><li>Shaw, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Infusion+of+reconstituted+high-density+lipoprotein+leads+to+acute+changes+in+human+atherosclerotic+plaque.">Infusion of reconstituted high-density lipoprotein leads to acute changes in human atherosclerotic plaque.</a> Circ. Res. 103, 1084-1091 (2008).</li><li>Kekulawala, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+freezing+on+high-density+lipoprotein+functionality.">Impact of freezing on high-density lipoprotein functionality.</a> Anal. Biochem. 379, 75-77 (2008).</li><li>D'Souza, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure/Function+Relationships+of+Apolipoprotein+A-I+Mimetic+Peptides:+Implications+for+Antiatherogenic+Activities+of+High-Density+Lipoprotein.">Structure/Function Relationships of Apolipoprotein A-I Mimetic Peptides: Implications for Antiatherogenic Activities of High-Density Lipoprotein.</a> Circ. Res. 107, 217-227 (2010).</li><li>Tchoua, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+cholesteryl+ester+transfer+protein+overexpression+and+inhibition+on+reverse+cholesterol+transport.">The effect of cholesteryl ester transfer protein overexpression and inhibition on reverse cholesterol transport.</a> Cardiovasc Res. 77, 732-739 (2008).</li><li>Mukhamedova, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhancing+apolipoprotein+A-I-dependent+cholesterol+efflux+elevates+cholesterol+export+from+macrophages+in+vivo.">Enhancing apolipoprotein A-I-dependent cholesterol efflux elevates cholesterol export from macrophages in vivo.</a> J. Lipid Res. 49, 2312-2322 (2008).</li><li>Mukhamedova, N., Fu, Y., Bukrinsky, M., Remaley, A. T., Sviridov, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Role+of+Different+Regions+of+ATP-Binding+Cassette+Transporter+A1+in+Cholesterol+Efflux.">The Role of Different Regions of ATP-Binding Cassette Transporter A1 in Cholesterol Efflux.</a> Biochemistry. 46, 9388-9398 (2007).</li><li>Sviridov, D., Fidge, N., Beaumier-Gallon, G., Fielding, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Apolipoprotein+A-I+stimulates+the+transport+of+intracellular+cholesterol+to+cell-surface+cholesterol-rich+domains+(caveolae.">Apolipoprotein A-I stimulates the transport of intracellular cholesterol to cell-surface cholesterol-rich domains (caveolae.</a> Biochem. J. 358, 79-86 (2001).</li><li>Smyth, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+mouse+model+of+harlequin+ichthyosis+delineates+a+key+role+for+abca12+in+lipid+homeostasis.">A mouse model of harlequin ichthyosis delineates a key role for abca12 in lipid homeostasis.</a> PLoS Genet. 4, e1000192-e1000192 (2008).</li><li>Fu, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+Caveolin-1+Enhances+Cholesterol+Efflux+in+Hepatic+Cells.">Expression of Caveolin-1 Enhances Cholesterol Efflux in Hepatic Cells.</a> J. Biol. Chem. 279, 14140-14146 (2004).</li><li>Calkin, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reconstituted+High-Density+Lipoprotein+Attenuates+Platelet+Function+in+Individuals+With+Type+2+Diabetes+Mellitus+by+Promoting+Cholesterol+Efflux.">Reconstituted High-Density Lipoprotein Attenuates Platelet Function in Individuals With Type 2 Diabetes Mellitus by Promoting Cholesterol Efflux.</a> Circulation. 120, 2095-2104 (2009).</li></ol>

Yazarlar bu çalışma ile ilgili hiçbir çatışan çıkarları beyan ederim.

Kolesterol akışı ölçmek için açıklanan yönteme hücreleri bir hücre dışı kolesterol alıcı için kolesterol hareketinin ölçülmesi için tasarlanmıştır. Bu metodoloji anlamada çok önemli hususlar vardır. Etiketleme ve alışım Tarif metodolojide etiketli kolesterol serumu içeren serum ilave edilir. Ayrıntılı olarak incelenmiştir asla rağmen, kolesterol serum lipoprotein içine dahil edilmiştir ve hücreleri tarafından alınmasını kab...

<table border="1"><tbody><tr><td> Reaktifler \ Hücreleri </td><td> HeLa </td><td> THP-1 </td><td> RAW </td><td> HUVEC </td><td> BHK-21 </td><td> HFF </td></tr><tr><td> Komple Medya </td><td colspan="3"> RPMI -% 10 FCS -% 1 L-glütamin -% 0,2 Kalem strep </td><td> M199 -% 5 FCS -% 1 L-glütamin -% 1 Pen Strep -% 2 HEPES (1M) -% 7 endotel hücre büyümesi takviyesi (EKG) </td><td colspan="2"> DMEM -% 10 FCS -% 1 L-glütamin -% 0,2 Kalem strep </td></tr><tr><td> Serum Ücretsiz Media </td><td colspan="3"> RPMI -% 1 L-glütamin -% 0,2 Kalem strep </td><td> M199 -% 1 L-glütamin -% 1 Pen Strep -% 2 HEPES (1M) -% 7 endotel hücre büyümesinith takviyesi (EKG) </td><td colspan="2"> DMEM -% 1 L-glütamin -% 0,2 Kalem strep </td></tr><tr><td> Passage Yöntemi </td><td> 1 x Tripsin </td><td> Süspansiyon </td><td> Kazımak </td><td colspan="3"> 1 x Tripsin </td></tr><tr><td> Passage Oranı </td><td> 03:10 </td><td> 01:03 </td><td></td><td> 01:20 </td><td> 01:03 </td><td> 01:03 </td></tr><tr><td> Hücre Etkinleştirme (opsiyonel) </td><td></td><td colspan="5"> TO-901.317 - LXR-agonist - Final kons. 4 uM </td></tr><tr><td> Diğer Reaktifler </td><td></td><td> forbol miristat-12 13-asetat (PMA) - Hücre farklılaşması - Final kons. 0.1μg/ml </td><td></td><td></td><td></td><td></td></tr></tbody></table>

cholesterol efflux assay

Hücrelerin kolesterol içeriği hücre zarının bozulması, apoptoz ve nekroz 1 bir hücreye sonuçları çok fazla veya çok az kolesterol, çok dar sınırlar içinde tutulmalıdır. Hücreler hücre içi sentezi ve plazma lipoprotein kaynak kolesterol, hem de kaynakları tamamen kolesterol için hücrelerin ihtiyaçlarını karşılamak için yeterli olabilir. Kolesterol sentezi ve alım süreçleri sıkı regüle ve kolesterol eksikliği azdır 2 olarak uygulanır. Aşırı kolesterol daha yaygın sorun 3&#39;tür. Hepatositlerin dışında ve bir dereceye adrenokortikal hücrelere, hücreler kolesterol düşmesine edemiyoruz. Hücreler kendi kolesterol miktarını azaltmak için iki seçeneğiniz var: aynı zamanda toksik kolesterol esterleri ile hücrelerin aşırı olarak kolesterol esterleri, sınırlı kapasiteli bir seçenek haline dönüştürmek kolesterol ve kolesterol akışı, potansiyel olarak sınırsız kapasiteye sahip bir seçenek. Kolesterol akışı bir specBöyle ATP bağlayıcı kaset taşıyıcı proteinler A1 (ABCA1) ve G1 (ABCG1) ve çöpçü reseptör tip B1 gibi hücre içi nakliyeciler, bir dizi ile düzenlenmiştir IFIC süreci. Plazma kolesterol doğal alıcı yüksek dansiteli lipoprotein (HDL) ve apolipoprotein AI olduğunu. Kolesterol akışı assay kültürü hücrelerinden kolesterol akışı oranı ölçmek için tasarlanmıştır. Bu kolesterol akışı ve / veya hücre serbest kolesterol kabul plazma alıcıları kapasitesini korumak için hücre kapasitesi ölçer. Deneyi aşağıdaki adımlardan oluşur. Adım 1: serum içeren orta etiketli kolesterol ekleme ve 24-48 saat hücreleri ile kuluçkaya hücresel kolesterol etiketleme. Bu adımda kolesterol hücrelerinin yüklenmesi ile kombine edilebilir. Adım 2: bütün hücre içi kolesterol havuzlarına etiketli kolesterol dengelenmeye serum içermeyen aracı madde içinde hücrelerinin inkübasyon. Bu aşamada hücresel kanal aktivasyonu ile kombine edilebilirolesterol taşımacıları. Adım 3: ekstraselüler alıcı ve hücreler arası alıcı için etiketli kolesterol hareketinin kantitatif sahip hücrelerin inkübasyon. Kolesterol öncüleri yeni sentezlenen kolesterol etiketlemek için kullanılması durumunda, bir dördüncü aşama, kolesterol saflaştırma, gerekli olabilir. Deneyi aşağıdaki bilgi sağlar: (i) belirli bir işlem (a mutasyonu, bir itici, aşağı, bir aşırı ekspresyonu ya da tedavi) efflux kolesterol hücre kapasitesi etkiler ve (ii) nasıl plazma alıcısının kapasitesi kolesterol kabul nasıl Bir hastalık veya bir tedavi tarafından etkilenir. Bu yöntem, çoğu zaman kardiyovasküler araştırmalar, metabolik ve nörodejeneratif hastalıklar, bulaşıcı hastalıklar ve üreme bağlamında kullanılır.

Watch this Scientific Journal Video about Cholesterol Efflux Assay at JoVE.com

Kolesterol Akışı Testi | Tıp | Video

Cholesterol Efflux Assay

Kolesterol tahlilini kültürü hücrelerinden kolesterol akışı hızı ve hücreler serbest kolesterol kabul plazma alıcısının kapasitesi ölçmek için tasarlanmıştır. Tahlil içi havuzu ve ekstrasellüler alıcı için kolesterol serbest bırakılması arasında kolesterol kolesterol, denge ile hücrelerin etiketlenmesi oluşur.

Kolesterol akışı Testi

Cholesterol content of cells must be maintained within the very tight limits, too much or too little cholesterol in a cell results in disruption of ...

Universidad de Cartagena UDEC

Research

Education

JoVE Journal

JoVE Core

Biology

Medicine

Fundamentals

Chemistry of Life

SCIENTISTS IN ACTION

29.7K Görüntüleme.  Baker IDI Heart and Diabetes Institute. Kolesterol tahlilini kültürü hücrelerinden kolesterol akışı hızı ve hücreler serbest kolesterol kabul plazma alıcısının kapasitesi ölçmek için tasarlanmıştır. Tahlil içi havuzu ve ekstrasellüler alıcı için kolesterol serbest bırakılması arasında kolesterol kolesterol, denge ile hücrelerin etiketlenmesi oluşur.

Video: Cholesterol Efflux Assay

Enrichment of Mammalian Tissues and Xenopus Oocytes with Cholesterol

Cholesterol enrichment of mammalian tissues and cells, including Xenopus oocytes used for studying cell function, can be accomplished using a variety of methods. Here, we describe two important approaches used for this purpose. First, we describe how to enrich tissues and cells with cholesterol using cyclodextrin saturated with cholesterol using cerebral arteries (tissues) and hippocampal neurons (cells) as examples. This approach can be used for any type of tissue, cells, or cell lines. An alternative approach for cholesterol enrichment involves the use of low-density lipoprotein (LDL). The advantage of this approach is that it uses part of the natural cholesterol homeostasis machinery of the cell. However, whereas the cyclodextrin approach can be applied to enrich any cell type of interest with cholesterol, the LDL approach is limited to cells that express LDL receptors (e.g., liver cells, bone marrow-derived cells such as blood leukocytes and tissue macrophages), and the level of enrichment depends on the concentration and the mobility of the LDL receptor. Furthermore, LDL particles include other lipids, so cholesterol delivery is nonspecific. Second, we describe how to enrich Xenopus oocytes with cholesterol using a phospholipid-based dispersion (i.e., liposomes) that includes cholesterol. Xenopus oocytes constitute a popular heterologous expression system used for studying cell and protein function. For both the cyclodextrin-based cholesterol enrichment approach of mammalian tissue (cerebral arteries) and for the phospholipid-based cholesterol enrichment approach of Xenopus oocytes, we demonstrate that cholesterol levels reach a maximum following 5 min of incubation. This level of cholesterol remains constant during extended periods of incubation (e.g., 60 min). Together, these data provide the basis for optimized temporal conditions for cholesterol enrichment of tissues, cells, and Xenopus oocytes for functional studies aimed at interrogating the impact of cholesterol enrichment.

Enrichment of Mammalian Tissues and Xenopus Oocytes with Cholesterol

Two methods of cholesterol enrichment are presented: the application of cyclodextrin saturated with cholesterol to enrich mammalian tissues and cells, and the use of cholesterol-enriched phospholipid-based dispersions (liposomes) to enrich Xenopus oocytes. These methods are instrumental for determining the impact of elevated cholesterol levels in molecular, cellular, and organ function.

Memeli Dokuları ve Kenopus Oositlerinin Kolesterol ile Zenginleşmesi

Cholesterol enrichment of mammalian tissues and cells, including Xenopus oocytes used for studying cell function, can be accomplished using a variety of ...

Biyokimya

Spot Variation Fluorescence Correlation Spectroscopy for Analysis of Molecular Diffusion at the Plasma Membrane of Living Cells

Dynamic biological processes in living cells, including those associated with plasma membrane organization, occur on various spatial and temporal scales, ranging from nanometers to micrometers and microseconds to minutes, respectively. Such a broad range of biological processes challenges conventional microscopy approaches. Here, we detail the procedure for implementing spot variation Fluorescence Correlation Spectroscopy (svFCS) measurements using a classical fluorescence microscope that has been customized. The protocol includes a specific performance check of the svFCS setup and the guidelines for molecular diffusion measurements by svFCS on the plasma membrane of living cells under physiological conditions. Additionally, we provide a procedure for disrupting plasma membrane raft nanodomains by cholesterol oxidase treatment and demonstrate how these changes in the lateral organization of the plasma membrane might be revealed by svFCS analysis. In conclusion, this fluorescence-based method can provide unprecedented details on the lateral organization of the plasma membrane with the appropriate spatial and temporal resolution.

This article aims to present a protocol on how to build a spot variation Fluorescence Correlation Spectroscopy (svFCS) microscope to measure molecular diffusion at the plasma membrane of living cells.

Canlı Hücrelerin Plazma Membranında Moleküler Difüzyonun Analizi için Spot Varyasyon Floresan Korelasyon Spektroskopisi

Dynamic biological processes in living cells, including those associated with plasma membrane organization, occur on various spatial and temporal scales, ...

Cell-free Biochemical Fluorometric Enzymatic Assay for High-throughput Measurement of Lipid Peroxidation in High Density Lipoprotein

Low high-density lipoprotein cholesterol (HDL-C) levels are one of the most powerful independent negative predictors of atherosclerotic cardiovascular disease (CVD). The structure and function of HDL rather than HDL-C may more accurately predict atherosclerosis. Several HDL protein and lipid compositional changes that impair HDL function occur in inflammatory states such as atherosclerosis. HDL function is usually determined by cell based assays such as cholesterol efflux assay but these assays have numerous drawbacks lack of standardization. Cell-free assays may give more robust measures of HDL function compared to cell-based assays. HDL oxidation impairs HDL function. HDL has a major role in lipid peroxide transport and high amount of lipid peroxides is related to abnormal HDL function. Lipid-probe interactions should be considered when interpreting the results of non-enzymatic fluorescence assays for measuring the lipid oxidative state. This motivated us to develop a cell-free biochemical enzymatic method to assess HDL lipid peroxide content (HDLox) that contributes to HDL dysfunction. This method is based on the enzyme horseradish peroxidase (HRP) and the fluorochrome Amplex Red that can quantify (without cholesterol oxidase) the lipid peroxide content per mg of HDL-C. Here a protocol is describedfor determination of HDL-lipid peroxidation using the fluorochrome reagent. Assay variability can be reduced by strict standardization of experimental conditions. Higher HDLox values are associated with reduced HDL antioxidant function. The readout of this assay is associated with readouts of validated cell-based assays, surrogate measures of cardiovascular disease, systemic inflammation, immune dysfunction, and associated cardiovascular and metabolic risk phenotypes. This technical approach is a robust method to assess HDL function in human disease where systemic inflammation, oxidative stress and oxidized lipids have a key role (such as atherosclerosis).

We describe here a fluorometric cell-free biochemical assay for determination of HDL-lipid peroxidation. This rapid and reproducible assay can be used to determine HDL function in large scale studies and can contribute to our understanding of HDL function in human disease.

Boş hücre biyokimyasal Fluorometrik enzimatik tahlil yüksek yoğunluklu Lipoprotein Lipid peroksidasyon yüksek üretilen iş ölçümü için

Low high-density lipoprotein cholesterol (HDL-C) levels are one of the most powerful independent negative predictors of atherosclerotic cardiovascular ...

İmmünoloji ve Enfeksiyon

Lipid Exchange Assay in Living Cells

Lipid rafts are dynamic, ordered domains in the plasma membrane often formed during membrane protein clustering and signaling. The lipid identity of the outer leaflet drives the membrane&#39;s propensity to form lipid rafts. The transient nature of lipid rafts makes it difficult to study in living cells. Therefore, methods that add or remove raft-forming lipids at&#160;the outer leaflet of living cells facilitate studying the characteristics of rafts, such as their effects on membrane proteins. Lipid exchange experiments developed in our lab utilize lipid-loaded cyclodextrins to remove and add exogenous phospholipids to change the lipid constitution of the plasma membrane. Substituting the membrane with a raft or non-raft-forming lipid can aid in studying the effects on transmembrane protein activity. Here, we describe a method for lipid exchange on the outer leaflet of the plasma membrane using lipid-loaded cyclodextrin. We demonstrate the preparation of the exchange media and the subsequent treatment of attached mammalian cells. We also showcase how to measure the efficiency of exchange using HP-TLC. This protocol yields a nearly complete replacement of the outer leaflet with exogenous lipids without altering cellular viability, permitting further experimentation on modified intact plasma membranes.

We describe a method for using cyclodextrin to mediate exchange between lipids of the plasma membrane with exogenous lipids. This technique can be paired with experiments studying transmembrane proteins, which behave differently in lipid raft-like environments than they do in non-raft-like environments.

Canlı Hücrelerde Lipid Değişim Testi

Lipid rafts are dynamic, ordered domains in the plasma membrane often formed during membrane protein clustering and signaling. The lipid identity of the ...

Differential Effects of Lipid-lowering Drugs in Modulating Morphology of Cholesterol Particles

Treatment of dyslipidemia patients with lipid-lowering drugs leads to a significant reduction in low-density lipoproteins (LDL) level and a low to moderate level of increase in high-density lipoprotein (HDL) cholesterol in plasma. However, a possible role of these drugs in altering morphology and distribution of cholesterol particles is poorly understood. Here, we describe the in vitro evaluation of lipid-lowering drug effects in modulating morphological features of cholesterol particles using the plaque array method in combination with imaging flow cytometry. Image analyses of the cholesterol particles indicated that lovastatin, simvastatin, ezetimibe, and atorvastatin induce the formation of both globular and linear strand-shaped particles, whereas niacin, fibrates, fluvastatin, and rosuvastatin induce the formation of only globular-shaped particles. Next, purified very low-density lipoprotein (VLDL) and LDL particles incubated with these drugs showed changes in the morphology and image texture of cholesterol particles subpopulations. Furthermore, screening of 50 serum samples revealed the presence of a higher level of linear shaped HDL cholesterol particles in subjects with dyslipidemia (mean of 18.3%) compared to the age-matched normal (mean of 11.1%) samples. We also observed considerable variations in lipid-lowering drug effects on reducing linear shaped LDL and HDL cholesterol particles formation in serum samples. These findings indicate that lipid-lowering drugs, in addition to their cell-mediated hypolipidemic effects, may directly modulate morphology of cholesterol particles by a non-enzymatic mechanism of action. The outcomes of these results have potential to inform diagnosis of atherosclerosis and predict optimal lipid-lowering therapy.

The objective of this study was to evaluate in vitro lipid-lowering drug effects in modulating the morphology of cholesterol particles. Comparison of lipid-lowering drugs revealed variations in their effect in modulating the morphological features of cholesterol particles.

Kolesterol parçacıkları morfolojisi oransal olarak Lipid düşürücü ilaçlar farklı etkileri

Treatment of dyslipidemia patients with lipid-lowering drugs leads to a significant reduction in low-density lipoproteins (LDL) level and a low to ...

Tıp

High-throughput Nitrobenzoxadiazole-labeled Cholesterol Efflux Assay

Atherosclerosis leads to cardiovascular disease (CVD). It is still unclear whether cholesterol-HDL (cHDL) concentration plays a causal role in atherosclerosis development. However, an important factor in early stages of atheroma plaque formation is cholesterol efflux capacity to HDL (the ability of HDL particles to accept cholesterol from macrophages) in order to avoid foam cell formation. This is a key step in avoiding the accumulation of cholesterol in the endothelium and a part of reverse cholesterol transport (RCT) to eliminate cholesterol through the liver. Cholesterol efflux capacity to serum or plasma in macrophage cell models is a promising tool that can be used as biomarker for atherosclerosis. Traditionally, [3H]-cholesterol has been used in cholesterol efflux assays. In this study, we aim to develop a safer and faster strategy using fluorescent labelled-cholesterol (NBD-cholesterol) in a cellular assay to trace the cholesterol uptake and efflux process in THP-1-derived macrophages. Finally, we optimize and standardize the NBD-cholesterol efflux method and develop a high-throughput analysis using 96-well plates.

Measurement of in vitro cholesterol efflux capacity to serum or plasma in macrophage cell models is a promising tool as a biomarker for atherosclerosis. In the present study, we optimize and standardize a fluorescent NBD-cholesterol efflux method and develop a high-throughput analysis using 96-well plates.

Yüksek işlem hacmi Nitrobenzoxadiazole etiketli kolesterol sızma tahlil

Atherosclerosis leads to cardiovascular disease (CVD). It is still unclear whether cholesterol-HDL (cHDL) concentration plays a causal role in ...

A Proteoliposome-Based Efflux Assay to Determine Single-molecule Properties of Cl- Channels and Transporters

The last 15 years have been characterized by an explosion in the ability to overexpress and purify membrane proteins from prokaryotic organisms as well as from eukaryotes. This increase has been largely driven by the successful push to obtain structural information on membrane proteins. However, the ability to functionally interrogate these proteins has not advanced at the same rate and is often limited to qualitative assays of limited quantitative value, thereby limiting the mechanistic insights that they can provide. An assay to quantitatively investigate the transport activity of reconstituted Cl- channels or transporters is described. The assay is based on the measure of the efflux rate of Cl- from proteoliposomes following the addition of the K+ ionophore valinomycin to shunt the membrane potential. An ion sensitive electrode is used to follow the time-course of ion efflux from proteoliposomes reconstituted with the desired protein. The method is highly suited for mechanistic studies, as it allows for the quantitative determination of key properties of the reconstituted protein, such as its unitary transport rate, the fraction of active protein and the molecular mass of the functional unit. The assay can also be utilized to determine the effect of small molecule compounds that directly inhibit/activate the reconstituted protein, as well as to test the modulatory effects of the membrane composition or lipid-modifying reagents. Where possible, direct comparison between results obtained using this method were found to be in good agreement with those obtained using electrophysiological approaches. The technique is illustrated using CLC-ec1, a CLC-type H+/Cl- exchanger, as a model system. The efflux assay can be utilized to study any Cl- conducting channel/transporter and, with minimal changes, can be adapted to study any ion-transporting protein.

A Proteoliposome-Based Efflux Assay to Determine Single-molecule Properties of Cl- Channels and Transporters

Proteoliposomes are used to study purified channels and transporters reconstituted in a well-defined biochemical environment. An experimental procedure to measure efflux mediated by these proteins is illustrated. The steps to prepare proteoliposomes, perform the recordings, and analyze data to quantitatively determine the functional properties of the reconstituted protein are described.

Bir Proteoliposome Tabanlı effluks Deney Cl Tek-molekül Properties belirleme<sup&gt; -</sup&gt; Kanallar ve Nakliyeciler

The last 15 years have been characterized by an explosion in the ability to overexpress and purify membrane proteins from prokaryotic organisms as well as ...

Biyoloji

Using Caco-2 Cells to Study Lipid Transport by the Intestine

Studies of dietary fat absorption are generally conducted by using an animal model equipped with a lymph cannula. Although this animal model is widely accepted as the in vivo model of dietary fat absorption, the surgical techniques involved are challenging and expensive. Genetic manipulation of the animal model is also costly and time consuming. The alternative in vitro model is arguably more affordable, timesaving, and less challenging. Importantly, the in vitro model allows investigators to examine the enterocytes as an isolated system, reducing the complexity inherent in the whole organism model. This paper describes how human colon carcinoma cells (Caco-2) can serve as an in vitro model to study the enterocyte transport of lipids, and lipid-soluble drugs and vitamins. It explains the proper maintenance of Caco-2 cells and the preparation of their lipid mixture; and it further discusses the valuable option of using the permeable membrane system. Since differentiated Caco-2 cells are polarized, the main advantage of using the permeable membrane system is that it separates the apical from the basolateral compartment. Consequently, the lipid mixture can be added to the apical compartment while the lipoproteins can be collected from the basolateral compartment. In addition, the effectiveness of the lentivirus expression system in upregulating gene expression in Caco-2 cells is discussed. Lastly, this paper describes how to confirm the successful isolation of intestinal lipoproteins by transmission electron microscopy (TEM).

Caco-2 cells can serve as an in vitro model to study the enterocyte transport of lipids, and lipid-soluble drugs/vitamins. The permeable membrane system separates the apical from the basolateral compartment, while the lentivirus expression system offers an effective gene overexpression method. The isolation of lipoproteins is confirmed by TEM.

Bağırsak tarafından Lipit Transport Eğitim için Caco-2 hücreleri kullanarak

Studies of dietary fat absorption are generally conducted by using an animal model equipped with a lymph cannula. Although this animal model is widely ...

LDL Cholesterol Uptake Assay Using Live Cell Imaging Analysis with Cell Health Monitoring

The regulation of LDL cholesterol uptake through LDLR-mediated endocytosis is an important area of study in various major pathologies including metabolic disorder, cardiovascular disease, and kidney disease. Currently, there is no available method to assess LDL uptake while simultaneously monitoring for health of the cells. The current study presents a protocol, using a live cell imaging analysis system, to acquire serial measurements of LDL influx with concurrent monitoring for cell health. This novel technique is tested in three human cell lines (hepatic, renal tubular epithelial, and coronary artery endothelial cells) over a four-hour time course. Moreover, the sensitivity of this technique is validated with well-known LDL uptake inhibitors, Dynasore and recombinant PCSK9 protein, as well as by an LDL uptake promoter, Simvastatin. Taken together, this method provides a medium-to-high throughput platform for simultaneously screening pharmacological activity as well as monitoring of cell morphology, hence cytotoxicity of compounds regulating LDL influx. The analysis can be used with different imaging systems and analytical software.

This protocol provides an efficient approach to measuring LDL cholesterol uptake with real time influx rates using a live cell imaging system in various cell types. This technique provides a platform to screen the pharmacological activity of compounds affecting LDL influx while monitoring for cell morphology and hence potential cytotoxicity.

LDL kolesterol alımını tahlil canlı hücre analizi ile hücre Imaging kullanarak sistem durumu izleme

The regulation of LDL cholesterol uptake through LDLR-mediated endocytosis is an important area of study in various major pathologies including metabolic ...

The Isolation of Flowing Mesenteric Lymph in Mice to Quantify In Vivo Kinetics of Dietary Lipid Absorption and Chylomicron Secretion

Intestinal lipoproteins, especially triglyceride-rich chylomicrons, are a major driver of metabolism, inflammation, and cardiovascular diseases. However, isolating intestinal lipoproteins is very difficult in vivo because they are first secreted from the small intestine into the mesenteric lymphatics. Chylomicron-containing lymph then empties into the subclavian vein from the thoracic duct to deliver components of the meal to the heart, lungs, and, ultimately, whole-body circulation. Isolating na&#239;ve chylomicrons is impossible from blood since chylomicron triglyceride undergoes hydrolysis immediately upon interaction with lipoprotein lipase and other lipoprotein receptors in circulation. Therefore, the original 2-day lymph fistula procedure, described by Bollman et al. in rats, has historically been used to isolate fresh mesenteric lymph before its entry into the thoracic vein. That protocol has been improved upon and professionalized by the laboratory of Patrick Tso for the last 45 years, allowing for the analysis of these critical lipoproteins and secretions from the gut. The Tso lymph fistula procedure has now been updated and is presented here visually for the first time. This revised procedure is a single-day surgical technique for installing a duodenal feeding tube, cannulating the mesenteric lymph duct, and collecting lymph after a meal in conscious mice. The major benefits of these new techniques include the ability to reproducibly collect lymph from mice (which harnesses the power of genetic mouse models); the reduced anesthesia time for mice during the implantation of the duodenal infusion tube and the lymph cannula; the ability to continuously sample lymph throughout the feeding and post-prandial period; the ability to quantitatively measure hormones and cytokines before their dilution and enzymatic hydrolysis in blood; and the ability to collect large quantities of lymph for isolating intestinal lipoproteins. This technique is a powerful tool for directly and quantitatively measuring dietary nutrient absorption, intestinal lipoprotein synthesis, and chylomicron secretion.

The Isolation of Flowing Mesenteric Lymph in Mice to Quantify In Vivo Kinetics of Dietary Lipid Absorption and Chylomicron Secretion

The present protocol describes a detailed surgical protocol for isolating flowing intestinal lymph in response to intraduodenal nutrient infusions in mice. This allows for the physiological determination of total intestinal lipid absorption and chylomicron synthesis and secretion in response to various experimental nutrients.

Diyet Lipid Emiliminin ve Şilomikron Sekresyonunun İn Vivo Kinetiğini Ölçmek için Farelerde Akan Mezenterik Lenflerin İzolasyonu

Intestinal lipoproteins, especially triglyceride-rich chylomicrons, are a major driver of metabolism, inflammation, and cardiovascular diseases. However, ...