Name: automated acoustic dispensing for the serial dilution of peptide agonists in potency determination assays
Uploaded: 2016-11-10T12:30:00.000+00:00
Duration: 8 min 6 s
Description: Watch this Scientific Journal Video about Automated Acoustic Dispensing for the Serial Dilution of Peptide Agonists in Potency Determination Assays at JoVE.com

1. Peptid seri seyreltme <ol><li> deney tamponu hazırlayın: Hanks, 25 mM HEPES,% 0.1 BSA ve 0.5 mM 3-izobutil-1-metilksantin (IBMX), pH 7.4 ile takviye edilmiş tuz çözeltisi (HBSS) tamponlu. </li><li> sistematik beş 384-düşük hacimli deney plakalarının her çukuruna deney tamponu 5 ul bir hacim tepkin madde dağıtıcı kullanın. <ol><li> üreticinin talimatlarına göre 384 oyuklu bir plakanın her bir oyuğuna 5 ul hacmi ilave edilmesi için bir dağıtma programı oluşturmak için iç yazılım kullanın. </li><li> deney tamponu ve prime sıvısında kaset boru dağıtım daldırın. </li><li> plaka taşıyıcısı üzerindeki 384 de düşük hacimli tahlil plaka koyun. </li><li> Başlata basınız. </li></ol></li><li> 100x peptid stokunun üretilmesi için deney tamponu içine ne olursa olsun, bir depolama aracı, her peptit örnekleri seyreltilir. Not: tarama gerektiren peptidlerdir örneğin, DMSO (w uygun görüldüğü şekilde fosfat-tamponlu salin (PBS) veya dimetil sülfoksit (DMSO) içinde temin edilebilirHasta bu PEGilasyon gibi sekonder değişikliklerin) sahip peptidler üzerinde zararlı bir etkiye sahiptir. </li><li> sütunlar akustik nitelikli 384-polipropilen mikroplaka 1-5 içine 25 ul 100x peptid stokları koyun. Bu plaka &#39;kaynak plaka A&#39; belirlenmiştir. bu kaynak plakaları olun, ancak hedef plakaları, düz dipli ve akustik enstrümanlar üreticisi tarafından tanımlanan belirli akustik toleranslar uygundur. </li><li> kuyular A23 içine 25 ul 100x referans kontrolü dağıtın ve kaynak plaka A. A24 </li><li> Kaynak plaka A. sütun 21-22 içine sütun 11-15 ve 30 ul tahlil tamponu içine 10 ul deney tamponu dağıtın </li><li> sütunlar ikinci akustik nitelikli 384 polipropilen mikroplaka 6-10 ve sütunları 16-20 içine 10 ul deney tamponu koyun. Bu plaka &#39;kaynak plaka B&#39; belirlenmiştir. </li><li> 1 dakika boyunca 300 x g&#39;de santrifüjleyin kaynağı A ve B levhalarının. uygun bir denge levhasını içerir. </li><li> akustik flui kullanınKaynak A sütun 1 100x peptid stokları (deney tamponu içinde), 100, ara seyreltiler: D dağıtıcılar, sıralı üç 1 hazırlanması için bir otomatik robotlu sisteme entegre NOT: Programlama kaynak A ve kaynak B (plaka düzenleri için bakınız Şekil 1) arasında üç akustik transferlerine izin plaka yeniden biçimlendirme ve (akustik sıvı dağıtıcısının üreticisi tarafından sağlanan gibi) doz-yanıt yazılım gerektirir. Özellikle 1,9 ayrıntıları otomatik robot kontrolü altında bu laboratuvarda kullanılan sıvı dağıtıcıları kullanımı Adım (Malzeme Tablo bakınız): <ol><li> robotik plaka otel bölümünde yükleyin kaynak plakaları ve tahlil plakaları. </li><li> Açık, otomatik robotlu yazılım ve yük plakası yeniden biçimlendirme ve doz-yanıt programı genişletme protokolleri. &#39;Çalıştır&#39; düğmesine tıklayın. NOT: Otomasyon kaynak plakası B sütunları 6-10 içine kaynak plakası A sütunları 1-5 250 nl aktarmak için bir akustik sıvı dağıtıcı talimatı ve ikinci akustik birkarıştırmak için 15 ul deney tamponu ile doldurmak için büyük sıvı hacimlerini işleme yeteneğine c sıvı dağıtıcısı. Otomasyon sonra entegre santrifüj ve 1 dakika boyunca 300 xg&#39;de santrifüj (uygun bir denge plakası tüm santrifüj adımları dahildir) kaynak plakası B aktarır. Kaynak plaka B kaynak plakası A sütunları 11-15 içine kaynak plakası B sütunları 6-10 250 nl transferi için akustik sıvı dağıtıcı döndü ve karıştırmak için 15 ul deney tamponu ile dolgu edilir. Entegre santrifüj ve 1 dakika boyunca 300 xg&#39;de santrifüj Otomasyon transferleri kaynak plakası A. Kaynak levhası ardından kaynak plakası B sütunları 16-20 içine kaynak plakası A sütunları 11-15 250 nl transferi için akustik sıvı dağıtıcı döndü ve karıştırmak için 15 ul deney tamponu ile dolgu edilir. Otomasyon sonra 1 dakika boyunca 300 xg&#39;de entegre santrifüj ve santrifüjler kaynak plakası B aktarır. NOT: Son olarak doz tepki protokolü aktarmak için akustik dağıtılmasını yönlendirir(Kaynak levhasının ve kaynak plakası B hem de) 4 seri olarak seyreltilmiş, kaynak plakası kuyularının her biri gerekli hacmi deney plakalarında iki kez tam 11 noktalı eğri oluşturmak için (yukarıda Adım 1.2&#39;de 5 ul deney tamponu ile önceden doldurulmuş ). Otomasyon Entegre santrifüj transferler tahlil plaka ve santrifüjler 1 dakika boyunca 300 xg&#39;de. </li></ol></li></ol> 2. Hücre Hazırlanması <ol><li> 20 mi tayin tamponu içinde 37 ° C bir su banyosu ve tekrar süspansiyon hızla hedef fare, GLP-1 reseptörü eksprese eden çözülme dondurulan Çin hamsteri yumurtalık (CHO) hücreleri. </li><li> Oda sıcaklığında 200 xg (RT), 5 dakika boyunca santrifüj hücre süspansiyonu. uygun bir denge ekleyin. </li><li> Süpernatant atın ve 10 ml tahlil tamponu hücre pelletini. </li><li> Tripan mavi 1 ve otomatik bir hücre sayacı kullanılarak, canlı hücrelerin yoğunluğunu belirler: hücre stoku: 1 seyreltin. Wel 8.000 hücrelerine (eşdeğer, ml başına 1.6 x 10 6 hücre olarak tahlil tamponu içinde yeniden süspanse hücreleriDeney plakaları l). </li><li> 30 dakika boyunca oda sıcaklığında (5 ul deney tamponu içinde seri halinde seyreltilmiş peptid içeren) deney plakalarının her çukuruna hücre süspansiyonu 5 ul ve inkübasyona bir kütle reaktif dağıtıcı kullanın. </li></ol> 3. HTRF cAMP tespitinde <ol><li> kullanımdan önce, 30 dakika boyunca oda sıcaklığına HTRF cAMP tahlili kiti getirin. </li><li> (CAMP tarama deneyinde üreticisi tarafından sağlanan özel formülasyon) liziz tamponu içinde 1:20 seyreltide ayrı ayrı HTRF reaktif (cryptate ve D2) hazırlayın. NOT: DİKKAT: Lizis tampon potasyum zehirlidir florid (KF) ve teratojen 13 içerir. Atıkları, KF içeren tahlil tabak mühürlü ve yakılarak ve herhangi bir sıvı atık önce lavaboya aşağı elden su ile &lt;1 mg / L seyreltilmiş gerekmektedir edilmelidir. </li><li> deney plakalarının tüm oyuklara 5 ul kriptat reaktif ekleme bir kütle reaktif dağıtıcı kullanın. </li><li> colum 5 ul d2 reaktifi eklemek için toplu reaktif dağıtıcı kullanınns tahlil plakaları 1-22. </li><li> Hemen el ile spesifik olmayan bağlanma (NSB) kontrol kuyuları ve kuyu E23-P24 içinde D2 reaktif 5 ul elde deney plakaları kuyu A23-D24 içinde 5 ul lizis tamponu pipetle. </li><li> kuyu karıştırmak oda sıcaklığında 200 xg&#39;de 1 dakika için deney plakaları santrifüjleyin. </li><li> buharlaşma ve foto-ağartma en aza indirmek ve 1 saat boyunca oda sıcaklığında inkübe tahlil plakaları örtün. </li><li> 620 nm&#39;de bir plaka okuyucu kullanılarak 665 nm &#39;de 320 nm&#39; de bir eksitasyon ve emisyon ile flüoresan rezonans enerji transferi (FRET) sinyali ölçer. </li></ol> 4. Veri Analizi <ol><li> tüm kuyulardan arka plan çıkarmak için NSB ortalama kullanın. </li><li> aşağıdaki şekilde 665 nm / 620 nm oranından% Delta F hesaplanır: Oran = (A 665nm / A 620) 10 4 x Delta F = ((Numune Oranı - Oran NSB) / Oran NSB)) x 100 nerede Oran NSB hiçbir d2 reaktifi ile kuyu =. </li><li> % Activat hesaplayınaşağıda uyarılmamış hücrelerde ve hücreler arasında iyon maksimum GLP-1 ligand ile uyarılmış: % Aktivasyon = (% Delta Fsample -% DeltaFunstimulated hücreleri) / (% DeltaFGLP-1 uyarılan hücreler -% DeltaF uyarılmamış hücreler) x 100 </li><li> Referans kontrol 1 ile tanımlanan,% aktivasyonu gibi 4-parametreli lojistik analizi ve grafik ile konsantrasyon-tepki eğrileri analiz edin. </li></ol>

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The authors have nothing to disclose.

Bu protokol, seri örnek 1 &#39;den az ul gerektiren, 3 x 10 6 bir konsantrasyon aralığı üzerinde peptid örnekleri seyreltilmesi için otomatik bir akustik dağıtma başarılı bir uygulama açıklanmaktadır. Bu yöntemin en önemli avantajı, normal reaktif ve karıştırmak için gerekli olan deney kapları (örneğin, pipet uçları gibi) plasticware örneklerin düşük maruz kalma ile plasticware peptit adsorpsiyonu en aza indirmek suretiyle veri kalitesinin artırmaktır. akustik dağıtım tamam...

GLP-1 R tip 2 diyabet 2 tedavisinde kurulu bir ilacın bir hedeftir. Bu reseptör için yerli peptit agonisti, GLP-1, 2-3 dakika 3 bir in vivo yarı-ömrü vardır. adenilil siklaz aktivasyonuna doğal G protein bağlanması yoluyla ikinci haberci cAMP&#39;nin alt üretimindeki G protein bağlı hedef reseptör sonuçlarına GLP-1 bağlanması. biriken cAMP ölçümü sağlam bir tahlil reseptör aktivasyonunun izlemek ve tercih edilen bir fiziko-kimyasal özellikleri, aktif GLP-1 analogları taranması için içerir. Böyle bir deney, konsantrasyon-tepki eğrilerini oluşturmak için test numunelerinin seri seyreltme gerektirir ve peptid örnekleri teslim Bu, özellikle karmaşıktır. Ucu tabanlı seri seyreltme hazırlanmasından potansiyel hatalar, daha önce 1,4,5 tarif edilmiştir. Peptidler güvenilmez potens tahminlerinde sonuçlanan plasticware yapışır. Peptit kaybı t yoluyla minimize edilebilirO sığır serum tamponlarda albümini (BSA) ve silikonlu plasticware kullanımı, ama bağlayıcı proteinin eklenmesi düzensiz kalmaktadır. Özel olarak, deney kaplarına GLP-1 bağlanması değişim 6 tarif edilmiştir. Sulu tahlil tampon içine ipuçları ve mikrotiter plakaları liç ve protein fonksiyonu 7, 8 engelleyebilir laboratuvar plasticware kullanılan bu istikrar ajanlar daha da komplikasyon var. Bu nedenle, yöntemler plasticware maruziyeti azaltmak için ölçümlerin doğruluğunu artırmak için gereklidir. Akustik Sıvı dağıtıcıları bitişik tahlil plaka 9 içinde hassas nanolitre damlacıklarının ejeksiyon sonuçlanan bir sıvı numunesinin yüzeyi üzerine, yüksek frekanslı akustik sinyal odaklanır. Akustik ejeksiyon kullanımı hazırlanması ve büyük sentetik bileşik kütüphanelerinin taranması için ilaç endüstrisinde standart ve teknoloji de küçük Moleküller için valide edilmiştires 10. Bildiğimiz kadarıyla, rekombinant ve sentetik peptidlerin hazırlanması için akustik dağıtılmasını tanımlamak için birinci grup ve daha önce bilinen ucu tabanlı yöntem 1 ile karşılaştırıldığında geliştirilmiş doğruluk bildirmiştir. Bu makalede, bir tam otomatik plaka taşıma robotik sistem üzerine temassız akustik transferi ile peptid seri ve direkt dilüsyonları hazırlanması entegrasyonunu anlatmaktadır. Örneklerin akustik transfer kapsayan bir dizi yöntem, daha önce, 11 tarif edilmiştir. Bu, iki aşamalı bir yöntem, ara stok konsantrasyonları hazırlamak için ve seri olarak tam doz-tepki eğrisi oluşturacak şekilde peptit analoglarını seyreltmek için kullanmaktadır. hazırlanan peptidler, hedef hücreler, fare GLP-1R ifade ile inkübe edilir, ve peptid agonisti activ bir okuma olarak, bu hücreler içinde, cAMP birikiminin ölçülmesi için ticari olarak elde edilebilen homojen zaman çözümlü bir fluoresans (HTRF) deneyi kullanımıSığ. Deney sağlam ve yüksek verimli bir 384-gözlü formata müsait ve rutin olarak, her iki deney geliştirme tatbik edildi ve ilaç tarama 12 çıkıntı olan.

<table><tbody><tr><td>Hanks&amp;rsquo; Balanced Salt solution</td><td>Sigma-Aldrich</td><td>H8264</td><td></td></tr><tr><td>HEPES</td><td>Sigma-Aldrich</td><td>H3375</td><td></td></tr><tr><td>Bovine Serum Albumin</td><td>Sigma-Aldrich</td><td>A9418</td><td></td></tr><tr><td>3-Isobutyl-1-methylxanthine</td><td>Sigma-Aldrich</td><td>I7018</td><td>Prepared as a 0.5 M stock in DMSO</td></tr><tr><td>GLP-1 (7-36) amide</td><td>Bachem</td><td>H-6795</td><td>Prepared as a 1 mg/ml stock in PBS, referred to as &#039;100x reference control&#039;</td></tr><tr><td>Test peptides</td><td>Produced in-house at MedImmune</td><td></td><td>Supplied at various concentrations in DMSO or PBS as appropriate</td></tr><tr><td>100x peptide stock</td><td>Produced in-house at MedImmune</td><td></td><td>Test peptide diluted into assay buffer to 100x final required concentration</td></tr><tr><td>Trypan Blue Solution, 0.4%</td><td>Thermo Fisher Scientific</td><td>15250-061</td><td></td></tr><tr><td>Cedex XS Cell Analyzer</td><td>Innovatis</td><td></td><td></td></tr><tr><td>Corning 384 well plates, low volume</td><td>Sigma-Aldrich</td><td>4514</td><td></td></tr><tr><td>Echo Qualified 384-Well Polypropylene Microplate</td><td>Labcyte Inc.</td><td>P-05525</td><td></td></tr><tr><td>Echo Qualified Reservoir</td><td>Labcyte Inc.</td><td>ER-0055</td><td></td></tr><tr><td>Echo 550 Liquid Handler</td><td>Labcyte Inc.</td><td></td><td>Droplet transfer volumes in increments of 2.5 nl</td></tr><tr><td>Echo 525 Liquid Handler</td><td>Labcyte Inc.</td><td></td><td>Droplet transfer volumes in increments of 25 nl</td></tr><tr><td>ACell Benchtop Automation&amp;nbsp;</td><td>HighRes Biosolutions</td><td>MC522</td><td></td></tr><tr><td>Cellario Lab Automation Scheduling software for Life Science Robotics</td><td>HighRes Biosolutions</td><td></td><td></td></tr><tr><td>MultidropCombi Reagent Dispenser</td><td>ThermFisher Scientific</td><td>5840300</td><td>Referred to as &#039;bulk reagent dispenser&#039;</td></tr><tr><td>HTRF cAMP Dynamic 2 kit</td><td>Cisbio Bioassays</td><td>62AM4PEJ</td><td></td></tr><tr><td>EnVision Multilabel Reader</td><td>PerkinElmer</td><td></td><td></td></tr></tbody></table>

automated acoustic dispensing for the serial dilution of peptide agonists in potency determination assays

küçük moleküllü ilaç keşfi olduğu gibi, peptid agonistleri için eleme konsantrasyon-tepki eğrileri elde etmek peptidlerin seri seyreltme gerektirir. peptidler Tarama geleneksel uç tabanlı numune alma yöntemleri adsorpsiyon yoluyla peptid kaybı için artan bir fırsat sağlayarak, plasticware geniş bir yüzey alanına peptidler maruz olarak karmaşıklık ek bir katman tanıyor. Plasticware aşırı maruz kalma önlenmesi plastik bağlılık yoluyla peptid kaybını azaltır ve böylece gücü tahmininde yanlışlıklar en aza indirir, ve biz daha önce peptid agonistleri 1 in vitro yüksek verimli tarama için dağıtım temassız akustik faydalarını tarif var. Burada fare glukagon benzeri peptit-1 reseptörü (GLP-1 R) peptit agonistlerinin taranmasında örnek kullanılarak mikrotiter plakalarında peptid seri dilüsyonları temassız akustik hazırlanması için bir tam entegre bir otomasyon çözümü tartışılmıştır. Bizim yöntemler yüksek izin-throughput agonistlerinin taranmasında da tahlilleri hücre bazlı ve kolay bir şekilde yüksek bir numune test etme desteklemek için, ya da (daha fazla hedef hücre çizgilerinin bir panel için, örneğin) deney plakası kopya sayısında artış sağlamak için büyütülebilir.

<html> Biz rutin akustik havalesiyle peptidler sulandırmak için iki adımlı bir yöntemini kullanın. İlk adımda, otomasyon ile uyumlu bir akustik dağıtıcı iki kaynak plakalar arasındaki dört stok peptid ara dilüsyonları oluşturmak için kullanılır (Şekil 1a, b). İkinci adım olarak, biz daha fazla her test peptid (Şekil 1c) için 11 maddelik konsantrasyon aralığı oluşturmak için kaynak plakaları A ve B hisse sene...

Watch this Scientific Journal Video about Automated Acoustic Dispensing for the Serial Dilution of Peptide Agonists in Potency Determination Assays at JoVE.com

Automated Acoustic Dispensing for the Serial Dilution of Peptide Agonists in Potency Determination Assays

Peptide adsorption to plasticware during traditional tip-based serial dilutions can significantly impact potency determination and confound the understanding of structure-activity relationships used for lead identification and lead optimization phases of drug discovery. Here methods for automated acoustic non-contact serial dilution of peptide samples are described.

Etkili belirlenmesi tahlillerinde Peptit Agonistlerinin seri Seyreltme için Dağıtım Otomatik Akustik

As with small molecule drug discovery, screening for peptide agonists requires the serial dilution of peptides to produce concentration-response curves. ...

automated-acoustic-dispensing-for-serial-dilution-peptide-agonists

Universidad San Sebastian

Research

JoVE Journal

Biochemistry

7.6K Görüntüleme.  MedImmune. Peptide adsorption to plasticware during traditional tip-based serial dilutions can significantly impact potency determination and confound the understanding of structure-activity relationships used for lead identification and lead optimization phases of drug discovery. Here methods for automated acoustic non-contact serial dilution of peptide samples are described. 

Video: Automated Acoustic Dispensing for the Serial Dilution of Peptide Agonists in Potency Determination Assays

Peptide and Protein Quantification Using Automated Immuno-MALDI (iMALDI)

Mass spectrometry (MS) is one of the most commonly used technologies for quantifying proteins in complex samples, with excellent assay specificity as a result of the direct detection of the mass-to-charge ratio of each target molecule. However, MS-based proteomics, like most other analytical techniques, has a bias towards measuring high-abundance analytes, so it is challenging to achieve detection limits of low ng/mL or pg/mL in complex samples, and this is the concentration range for many disease-relevant proteins in biofluids such as human plasma. To assist in the detection of low-abundance analytes, immuno-enrichment has been integrated into the assay to concentrate and purify the analyte before MS measurement, significantly improving assay sensitivity. In this work, the immuno- Matrix-Assisted Laser Desorption/Ionization (iMALDI) technology is presented for the quantification of proteins and peptides in biofluids, based on immuno-enrichment on beads, followed by MALDI-MS measurement without prior elution. The anti-peptide antibodies are functionalized on magnetic beads, and incubated with samples. After washing, the beads are directly transferred onto a MALDI target plate, and the signals are measured by a MALDI-Time of Flight (MALDI-TOF) instrument after the matrix solution has been applied to the beads. The sample preparation procedure is simplified compared to other immuno-MS assays, and the MALDI measurement is fast. The whole sample preparation is automated with a liquid handling system, with improved assay reproducibility and higher throughput. In this article, the iMALDI assay is used for determining the peptide angiotensin I (Ang I) concentration in plasma, which is used clinically as readout of plasma renin activity for the screening of primary aldosteronism (PA).

Peptide and Protein Quantification Using Automated Immuno-MALDI iMALDI

A protocol for the protein quantification in complex biological fluids using automated immuno-MALDI (iMALDI) technology is presented.

Peptid ve Protein miktar kullanarak otomatik IMMUNO-maldı (iMALDI)

Mass spectrometry (MS) is one of the most commonly used technologies for quantifying proteins in complex samples, with excellent assay specificity as a ...

Kimya

Drug-induced Sensitization of Adenylyl Cyclase: Assay Streamlining and Miniaturization for Small Molecule and siRNA Screening Applications

Sensitization of adenylyl cyclase (AC) signaling has been implicated in a variety of neuropsychiatric and neurologic disorders including substance abuse and Parkinson&#39;s disease. Acute activation of G&#945;i/o-linked receptors inhibits AC activity, whereas persistent activation of these receptors results in heterologous sensitization of AC and increased levels of intracellular cAMP. Previous studies have demonstrated that this enhancement of AC responsiveness is observed both in vitro and in vivo following the chronic activation of several types of G&#945;i/o-linked receptors including D2 dopamine and &#956; opioid receptors. Although heterologous sensitization of AC was first reported four decades ago, the mechanism(s) that underlie this phenomenon remain largely unknown. The lack of mechanistic data presumably reflects the complexity involved with this adaptive response, suggesting that nonbiased approaches could aid in identifying the molecular pathways involved in heterologous sensitization of AC. Previous studies have implicated kinase and Gb&#947; signaling as overlapping components that regulate the heterologous sensitization of AC. To identify unique and additional overlapping targets associated with sensitization of AC, the development and validation of a scalable cAMP sensitization assay is required for greater throughput. Previous approaches to study sensitization are generally cumbersome involving continuous cell culture maintenance as well as a complex methodology for measuring cAMP accumulation that involves multiple wash steps. Thus, the development of a robust cell-based assay that can be used for high throughput screening (HTS) in a 384&#160;well format would facilitate future studies. Using two D2 dopamine receptor cellular models (i.e.&#160;CHO-D2L and HEK-AC6/D2L), we have converted our 48-well sensitization assay (&#62;20 steps 4-5 days) to a five-step, single day assay in 384-well format. This new format is amenable to small molecule screening, and we demonstrate that this assay design can also be readily used for reverse transfection of siRNA in anticipation of targeted siRNA library screening.

Persistent activation of inhibitory G protein-coupled receptors results in sensitization of adenylyl cyclase signaling. To identify the essential molecular pathways, nonbiased approaches are necessary; however, this strategy requires the development of a scalable cell-based cAMP sensitization assay. Herein, we describe a sensitization assay for small molecule and siRNA screening.

Adenilat siklaz uyuşturucu kaynaklı Sensitizasyonu: Küçük Molekül ve siRNA Tarama Uygulamaları için Deney düzene ve minyatür

Sensitization of adenylyl cyclase (AC) signaling has been implicated in a variety of neuropsychiatric and neurologic disorders including substance abuse ...

Biyomühendislik

Stepwise Dosing Protocol for Increased Throughput in Label-Free Impedance-Based GPCR Assays

Label-free impedance-based assays are increasingly used to non-invasively study ligand-induced GPCR activation in cell culture experiments. The approach provides real-time cell monitoring with a device-dependent time resolution down to several tens of milliseconds and it is highly automated. However, when sample numbers get high (e.g., dose-response studies for various different ligands), the cost for the disposable electrode arrays as well as the available time resolution for sequential well-by-well recordings may become limiting. Therefore, we here present a serial agonist addition protocol which has the potential to significantly increase the output of label-free GPCR assays. Using the serial agonist addition protocol, a GPCR agonist is added sequentially in increasing concentrations to a single cell layer while continuously monitoring the sample&#39;s impedance (agonist mode). With this serial approach, it is now possible to establish a full dose-response curve for a GPCR agonist from just one single cell layer. The serial agonist addition protocol is applicable to different GPCR coupling types, Gq Gi/0 or Gs and it is compatible with recombinant and endogenous expression levels of the receptor under study. Receptor blocking by GPCR antagonists is assessable as well (antagonist mode).

This protocol demonstrates real-time recording of full dose-response relationships for agonist-induced GPCR activation from a single cell layer grown on a single microelectrode using label-free impedance measurements. The new dosing scheme significantly increases throughput without loss in time resolution.

Label-Free Empedans Tabanlı GPCR Denemelerinde Artırılmış İş İlerletme Protokolü

Label-free impedance-based assays are increasingly used to non-invasively study ligand-induced GPCR activation in cell culture experiments. The approach ...

Biyokimya

Scalable High Throughput Selection From  Phage-displayed Synthetic Antibody Libraries

The demand for antibodies that fulfill the needs of both basic and clinical research applications is high and will dramatically increase in the future. However, it is apparent that traditional monoclonal technologies are not alone up to this task. This has led to the development of alternate methods to satisfy the demand for high quality and renewable affinity reagents to all accessible elements of the proteome. Toward this end, high throughput methods for conducting selections from phage-displayed synthetic antibody libraries have been devised for applications involving diverse antigens and optimized for rapid throughput and success. Herein, a protocol is described in detail that illustrates with video demonstration the parallel selection of Fab-phage clones from high diversity libraries against hundreds of targets using either a manual 96 channel liquid handler or automated robotics system. Using this protocol, a single user can generate hundreds of antigens, select antibodies to them in parallel and validate antibody binding within 6-8 weeks. Highlighted are: i) a viable antigen format, ii) pre-selection antigen characterization, iii) critical steps that influence the selection of specific and high affinity clones, and iv) ways of monitoring selection effectiveness and early stage antibody clone characterization. With this approach, we have obtained synthetic antibody fragments (Fabs) to many target classes including single-pass membrane receptors, secreted protein hormones, and multi-domain intracellular proteins. These fragments are readily converted to full-length antibodies and have been validated to exhibit high affinity and specificity. Further, they have been demonstrated to be functional in a variety of standard immunoassays including Western blotting, ELISA, cellular immunofluorescence, immunoprecipitation and related assays. This methodology will accelerate antibody discovery and ultimately bring us closer to realizing the goal of generating renewable, high quality antibodies to the proteome.

A method is described with visual accompaniment for conducting scalable, high throughput selections from phage-displayed combinatorial synthetic antibody libraries against hundreds of antigens simultaneously. Using this parallel approach, we have isolated antibody fragments that exhibit high affinity and specificity for diverse antigens that are functional in standard immunoassays.

Faj-görüntülenen Sentetik Antikor Kütüphaneler itibaren Ölçeklenebilir Yüksek Verim Seçimi

The demand for antibodies that fulfill the needs of both basic and clinical research applications is high and will dramatically increase in the future. ...

İmmünoloji ve Enfeksiyon

A "Dual-Addition" Calcium Fluorescence Assay for the High-Throughput Screening of Recombinant G Protein-Coupled Receptors

G protein-coupled receptors (GPCRs) represent the largest superfamily of receptors and are the targets of numerous human drugs. High-throughput screening (HTS) of random small molecule libraries against GPCRs is used by the pharmaceutical industry for target-specific drug discovery. In this study, an HTS was employed to identify novel small-molecule ligands of invertebrate-specific neuropeptide GPCRs as probes for physiological studies of vectors of deadly human and veterinary pathogens.
The invertebrate-specific kinin receptor was chosen as a target because it regulates many important physiological processes in invertebrates, including diuresis, feeding, and digestion. Furthermore, the pharmacology of many invertebrate GPCRs is poorly characterized or not characterized at all; therefore, the differential pharmacology of these groups of receptors with respect to the related GPCRs in other metazoans, especially humans, adds knowledge to the structure-activity relationships of GPCRs as a superfamily. An HTS assay was developed for cells in 384-well plates for the discovery of ligands of the kinin receptor from the cattle fever tick, or southern cattle tick, Rhipicephalus microplus. The tick kinin receptor was stably expressed in CHO-K1 cells.
The kinin receptor, when activated by endogenous kinin neuropeptides or other small molecule agonists, triggers Ca2+ release from calcium stores into the cytoplasm. This calcium fluorescence assay combined with a &#34;dual-addition&#34; approach can detect functional agonist and antagonist &#34;hit&#34; molecules in the same assay plate. Each assay was conducted using drug plates carrying an array of 320 random small molecules. A reliable Z&#39; factor of 0.7 was obtained, and three agonist and two antagonist hit molecules were identified when the HTS was at a 2 &#181;M final concentration. The calcium fluorescence assay reported here can be adapted to screen other GPCRs that activate the Ca2+ signaling cascade.

In this work, a high-throughput, intracellular calcium fluorescence assay for 384-well plates to screen small molecule libraries on recombinant G protein-coupled receptors (GPCRs) is described. The target, the kinin receptor from the cattle fever tick, Rhipicephalus microplus, is expressed in CHO-K1 cells. This assay identifies agonists and antagonists using the same cells in one "dual-addition" assay.

Rekombinant G Proteinine Bağlı Reseptörlerin Yüksek Verimli Taraması için "Çift İlaveli" Bir Kalsiyum Floresan Testi

G protein-coupled receptors (GPCRs) represent the largest superfamily of receptors and are the targets of numerous human drugs. High-throughput screening ...

"Cell Surface Capture" Workflow for Label-Free Quantification of the Cell Surface Proteome

Over the past decade, mass spectrometry-based proteomics has enabled an in-depth characterization of biological systems across a broad array of applications. The cell surface proteome ("surfaceome") in human disease is of significant interest, as plasma membrane proteins are the primary target of most clinically approved therapeutics, as well as a key feature by which to diagnostically distinguish diseased cells from healthy tissues. However, focused characterization of membrane and surface proteins of the cell has remained challenging, primarily due to the complexity of cellular lysates, which mask proteins of interest by other high-abundance proteins. To overcome this technical barrier and accurately define the cell surface proteome of various cell types using mass spectrometry proteomics, it is necessary to enrich the cell lysate for cell surface proteins prior to analysis on the mass spectrometer. This paper presents a detailed workflow for labeling cell surface proteins from cancer cells, enriching these proteins out of the cell lysate, and subsequent sample preparation for mass spectrometry analysis.

Here, we describe a proteomics workflow for characterization of the cell surface proteome of various cell types. This workflow includes cell surface protein enrichment, subsequent sample preparation, analysis using an LC-MS/MS platform, and data processing with specialized software.

Over the past decade, mass spectrometry-based proteomics has enabled an in-depth characterization of biological systems across a broad array of ...

Synthesis of Monocyte-targeting Peptide Amphiphile Micelles for Imaging of Atherosclerosis

Atherosclerosis is a major contributor to cardiovascular disease, the leading cause of death worldwide, which claims 17.3 million lives annually. Atherosclerosis is also the leading cause of sudden death and myocardial infarction, instigated by unstable plaques that rupture and occlude the blood vessel without warning. Current imaging modalities cannot differentiate between stable and unstable plaques that rupture. Peptide amphiphiles micelles (PAMs) can overcome this drawback as they can be modified with a variety of targeting moieties that bind specifically to diseased tissue. Monocytes have been shown to be early markers of atherosclerosis, while large accumulation of monocytes is associated with plaques prone to rupture. Hence, nanoparticles that can target monocytes can be used to discriminate different stages of atherosclerosis. To that end, here, we describe a protocol for the preparation of monocyte-targeting PAMs (monocyte chemoattractant protein-1 (MCP-1) PAMs). MCP-1 PAMs are self-assembled through synthesis under mild conditions to form nanoparticles of 15 nm in diameter with near neutral surface charge. In vitro, PAMs were found to be biocompatible and had a high binding affinity for monocytes. The methods described herein show promise for a wide range of applications in atherosclerosis as well as other inflammatory diseases.

This paper presents a method involving the synthesis and characterization of monocyte-targeting peptide amphiphile micelles and the corresponding assays to test for biocompatibility and ability of the micelle to bind to monocytes.

Monosit hedefleme peptid Amfifil Micelles için düşsel ateroskleroz sentezi

Atherosclerosis is a major contributor to cardiovascular disease, the leading cause of death worldwide, which claims 17.3 million lives annually. ...

Quantification of Proteins Using Peptide Immunoaffinity Enrichment Coupled with Mass Spectrometry

There is a great need for quantitative assays in measuring proteins. Traditional sandwich immunoassays, largely considered the gold standard in quantitation, are associated with a high cost, long lead time, and are fraught with drawbacks (e.g. heterophilic antibodies, autoantibody interference, 'hook-effect').1 An alternative technique is affinity enrichment of peptides coupled with quantitative mass spectrometry, commonly referred to as SISCAPA (Stable Isotope Standards and Capture by Anti-Peptide Antibodies).2 In this technique, affinity enrichment of peptides with stable isotope dilution and detection by selected/multiple reaction monitoring mass spectrometry (SRM/MRM-MS) provides quantitative measurement of peptides as surrogates for their respective proteins. SRM/MRM-MS is well established for accurate quantitation of small molecules 3, 4 and more recently has been adapted to measure the concentrations of proteins in plasma and cell lysates.5-7 To achieve quantitation of proteins, these larger molecules are digested to component peptides using an enzyme such as trypsin. One or more selected peptides whose sequence is unique to the target protein in that species (i.e. "proteotypic" peptides) are then enriched from the sample using anti-peptide antibodies and measured as quantitative stoichiometric surrogates for protein concentration in the sample. Hence, coupled to stable isotope dilution (SID) methods (i.e. a spiked-in stable isotope labeled peptide standard), SRM/MRM can be used to measure concentrations of proteotypic peptides as surrogates for quantification of proteins in complex biological matrices. The assays have several advantages compared to traditional immunoassays. The reagents are relatively less expensive to generate, the specificity for the analyte is excellent, the assays can be highly multiplexed, enrichment can be performed from neat plasma (no depletion required), and the technique is amenable to a wide array of proteins or modifications of interest.8-13 In this video we demonstrate the basic protocol as adapted to a magnetic bead platform.

Stable Isotope Standards and Capture by Anti-Peptide Antibodies (SISCAPA) couples affinity enrichment of peptides with stable isotope dilution mass spectrometry (MRM-MS) to provide quantitative measurement of peptides as surrogates for their respective proteins. Here we describe the protocol using magnetic particles in a partially automated format.

Proteinler Peptid immunoaffiniti Zenginleştirme kullanarak Niceleme Kütle Spektrometresi ile birleştiğinde

There is a great need for quantitative assays in measuring proteins. Traditional sandwich immunoassays, largely considered the gold standard in ...

Biyoloji

A High Throughput MHC II Binding Assay for Quantitative Analysis of Peptide Epitopes

Biochemical assays with recombinant human MHC II molecules can provide rapid, quantitative insights into immunogenic epitope identification, deletion, or design1,2. Here, a peptide-MHC II binding assay is scaled to 384-well format. The scaled down protocol reduces reagent costs by 75% and is higher throughput than previously described 96-well protocols1,3-5. Specifically, the experimental design permits robust and reproducible analysis of up to 15 peptides against one MHC II allele per 384-well ELISA plate. Using a single liquid handling robot, this method allows one researcher to analyze approximately ninety test peptides in triplicate over a range of eight concentrations and four MHC II allele types in less than 48 hr. Others working in the fields of protein deimmunization or vaccine design and development may find the protocol to be useful in facilitating their own work. In particular, the step-by-step instructions and the visual format of JoVE should allow other users to quickly and easily establish this methodology in their own labs.

Biochemical assays with recombinant human MHC II molecules can provide rapid, quantitative insights into immunogenic epitope identification, deletion, or design. &#160;Here, a peptide-MHC II binding assay scaled to 384-well plates is described. This cost effective format should prove useful in the fields of protein deimmunization and vaccine design and development.

Peptid Epitopların Kantitatif Analiz için bir yüksek veri akışı MHC II Bağlanma Deneyi

Biochemical assays with recombinant human MHC II molecules can provide rapid, quantitative insights into immunogenic epitope identification, deletion, or ...

Simple Bulk Readout of Digital Nucleic Acid Quantification Assays

Digital assays are powerful methods that enable detection of rare cells and counting of individual nucleic acid molecules. However, digital assays are still not routinely applied, due to the cost and specific equipment associated with commercially available methods. Here we present a simplified method for readout of digital droplet assays using a conventional real-time PCR instrument to measure bulk fluorescence of droplet-based digital assays.
We characterize the performance of the bulk readout assay using synthetic droplet mixtures and a droplet digital multiple displacement amplification (MDA) assay. Quantitative MDA particularly benefits from a digital reaction format, but our new method&#160;applies to any digital assay. For established digital assay protocols such as digital PCR, this method serves to speed up and simplify assay readout.
Our bulk readout methodology brings the advantages of partitioned assays without the need for specialized readout instrumentation. The principal limitations of the bulk readout methodology are reduced dynamic range compared with droplet-counting platforms and the need for a standard sample, although the requirements for this standard are less demanding than for a conventional real-time experiment. Quantitative whole genome amplification (WGA) is used to test for contaminants in WGA reactions and is the most sensitive way to detect the presence of DNA fragments with unknown sequences, giving the method great promise in diverse application areas including pharmaceutical quality control and astrobiology.

We describe an endpoint digital assay for quantifying nucleic acids with a simplified (analog) readout. We measure bulk fluorescence of droplet-based digital assays using a standard qPCR machine rather than specialized instrumentation and confirm our results by microscopy.

Dijital Nükleik Asit Kantifikasyon Tahliller Basit Toplu Saati

Digital assays are powerful methods that enable detection of rare cells and counting of individual nucleic acid molecules. However, digital assays are ...