Bioluminescence

Illuminating the Brain with a New Bioluminescence Imaging Substrate

Posted on by Kari Kenefick

Bioluminescence imaging is a powerful tool for non-invasive studies of the effect of treatments on cells and tissues. The luminescent signal is strong, and can be used in vivo, enabling repeated observations over time, allowing longitudinal study of cellular changes for hours or days. Bioluminescence imaging can be used in live animals over varying periods of time, without interfering with normal cellular processes.

Fluorescence imaging is also used in cellular studies. Although it can provide a stronger signal than luminescence, fluorescence requires light for excitation, and thus its in vivo use is limited at a tissue or cell depth greater than 1mm.

NanoLuc® Luciferase. Small, bright and now useful in brain bioluminescence imaging.

In addition, autofluorescence can be an issue with fluorescence imaging, as cellular components and surrounding proteins and cells can fluoresce when exposed to light. Autofluorescence can result in high background signals, making it difficult to distinguish true fluorescence from background.

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Scaling Up to Measure 40,000 Data Points a Day with GloMax® Microplate Readers

Posted on by Jordan Nutting

Traditional approaches for protein degrader compound screening like Western blotting can be laborious, time consuming and cannot be streamlined with automation. By implementing a high-throughput, automated workflow that uses our CRISPER/Cas9 knock-in cell lines, live-cell bioluminescent assays and sensitive GloMax® Discover microplate readers, our custom assay services offer protein degradation profiling at an accelerated rate.  

To do this, we collaborated with HighRes® Biosolutions, to develop an automated system that can screen up to 100 384-well plates each day, generating roughly 40,000 data points with minimal hands-on work.

Learn how bioluminescent tools like HiBiT and NanoBRET™ technology can help you answer key questions in your targeted protein degradation research.

An important step of building this system is to integrate four GloMax® Discover microplate readers into the automated system using instrument’s built-in SiLA2 communication driver. The driver software makes it easy to connect the microplate readers with HighRes® Biosolution’s robotic components.

Check out our setup in the video below.

See how we’ve integrated GloMax® Discover microplate readers into a high-throughput automated system for profiling protein degraders in live cells.
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Designing Better Therapeutic mAbs: An Assay for Rapid, Parallel Screening of Fc/ FcɣR Interactions

Posted on by Michele Arduengo

The first monoclonal antibody (mAb) was produced in a lab 1975, and the first therapeutic mAb was introduced in the United States to prevent kidney transplant rejection in 1986. The first mAb used in cancer treatment the anti-CD20 mAb, rituximab, was used to treat non-Hodgkin’s lymphoma and chronic lymphocytic leukemia. Today therapeutic mAbs have become a mainstay of cancer, autoimmune disease, and metabolic disease therapies and include HERCEPTIN® used to treat certain forms of breast cancer, Prolia used to treat bone loss in post-menopausal women, and Stelara used to treat autoimmune diseases like psoriatic arthritis and severe Crohn disease, among many others. Therapeutic mAbs bind targets with high specificity and affinity and they can recruit effector cells to drive target elimination through mechanisms such as antibody-dependent cellular cytotoxicity (ADCC) or antibody-dependent cellular phagocytosis (ADCP), making them highly specific, effective therapies.

3D rendering of a Lumit Assay which can be used for plate-based screening assay to measure the affinities of Fc interactions of therapeutic mAbs.
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Cytochrome P450 Inhibition: Old Drug, New Tricks

Posted on by Darcia Schweitzer
multiwell screening plate and various pills on a table

Cytochrome P450 (CYP) inhibitors are often used as boosting agents in combination with other drugs. This drug development strategy is front and center for Paxlovid, the new anti-SARS-CoV-2 treatment from Pfizer. Paxlovid is a combination therapy, comprised of two protease inhibitors, nirmatrelvir and ritonavir. It significantly reduces the risk of COVID-19 hospitalization in high-risk adults and is ingested orally rather than injected, which is an advantage over other SARS-CoV-2 treatments, such as Remdesivir.

Nirmatrelvir was originally developed by Pfizer almost 20 years ago to treat HIV and works by blocking enzymes that help viruses replicate. Pfizer created another version of this drug to combat SARS in 2003, but, once that outbreak ended, further development was put on pause until the advent of the COVID-19 pandemic. After developing an intravenous form of nirmatrelvir early in the pandemic, Pfizer created another version that can be taken orally and combined it with ritonavir.

When ritonavir was originally developed, it wasn’t considered particularly useful because it metabolized so quickly in the body. Now it is recognized as a pharmacokinetic enhancer in combination with other drugs. Ritonivir inhibits CYP3A4, an enzyme which plays a key role in the metabolism of drugs and xenobiotics. By inhibiting CYP3A4, ritonivir slows the metabolism of other drugs. In the case of Paxlovid, this allows nirmatrelvir to stay in the body longer at a high enough concentration to be effective against the virus. This ultimately means that patients can be given lower doses of the drug with reducing efficacy.

Diagram of Nirmaltrelvir mechanism of action.
Nirmatrelvir inhibits the viral 3CL protease, so that functional, smaller viral proteins cannot be produced.
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Study Reveals New Strategies for Targeting “Undruggable” KRAS Mutants

Posted on by Jordan Villanueva
NanoBRET assays can be used to understand the behavior of drugs targeting KRAS mutants

A new study published in Nature Chemical Biology shows that the most commonly mutated protein in cancer might not be as “undruggable” as previously believed. Promega R&D scientists collaborated with the research group led by Kevan Shokat at the University of California – San Francisco to develop strategies for targeting mutants of KRAS that have evaded previous drug discovery efforts. Their paper opens new possibilities for developing small molecule inhibitors against KRAS(G12D) and other clinically significant mutants.

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GPCRs and PROTACs: New Approaches for Designing More Effective Drug Candidates

Posted on by Ken Doyle
NanoBRET target engagement assay

G protein-coupled receptors (GPCRs) comprise a large group of cell surface receptors, characterized by the unique structural property of crossing the cell membrane seven times. They respond to a diverse group of signaling molecules, such as peptides, neurotransmitters, cytokines, hormones and other small molecules (1). Upon activation, GPCRs interact with GTP-binding (G) proteins and arrestins to regulate a wide variety of signaling pathways. This broad range of functions makes GPCRs attractive targets for drug discovery. The importance of GPCR research was highlighted in 2012, with the Nobel Prize in chemistry being awarded to Robert Lefkowitz and Brian Kobilka “for studies of G-protein–coupled receptors”.

Based on structure and function, GPCRs are categorized into six classes, A–F. The class A GPCRs, or rhodopsin-like receptors, have been studied extensively due to their association with many types of diseases (2). Within the class A GPCRs is a group that share a highly conserved structural motif (3) and respond to chemokines—small “chemotactic cytokines” that stimulate cell migration, especially that of white blood cells (4). A subfamily of class A GPCRs respond to chemokines that have two cysteine residues near the N-terminus, known as CC chemokines. GPCRs activated by CC chemokines are called CC chemokine receptors or CCRs, and these interactions have been implicated in both pro- and anti-cancer pathways (5).

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How to Get Real-Time Kinetic Data With GloMax® Microplate Readers

Posted on by Johanna Lee

Understanding how a compound or drug affects cellular pathways often requires measuring kinetic changes over an extended period of time—from several hours to days. Live-cell kinetic cell-based assays that measure cell viability, cytotoxicity, apoptosis and other cellular pathways are great for collecting real-time data. You don’t necessarily need expensive equipment to run these types of assays. In the videos below, Dr. Sarah Mahan, a research scientist at Promega, demonstrates how you can easily get great 24-hour or multi-day kinetic data using a GloMax® Microplate Reader.

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There’s a Microbiome In My Tank!

Posted on by Jordan Nutting

Imagine a scenario—you’re studying the developmental biology of a species of squid. The squid don’t reproduce in captivity, so females carrying fertilized eggs are collected from the wild and rehomed in your lab’s aquariums. You’ve monitored all the normal aquarium conditions—pH, temperature, salinity—ensuring the animal’s new home mimics its natural environment.

But then, for no reason apparent to you, the clutch of eggs doesn’t develop and doesn’t hatch, derailing your research program until next year when you can collect more adult squid from the wild. What went wrong?

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Virus-Like Particles: All the Bark, None of the Bite

Posted on by Ken Doyle

Globally, there have been over 5 million deaths attributed to COVID-19 since the start of the pandemic. Throughout the ongoing battle against SARS-CoV-2, researchers have been studying the viral lineage and the variants that are emerging as the virus evolves over time. The more opportunities that the virus has to replicate (i.e., the more people it infects), the greater the likelihood that a new variant will emerge.

This short video from the World Health Organization explains how viral variants develop.

The US Centers for Disease Control and Prevention (CDC) classify SARS-CoV-2 variants into four groups: Variants Being Monitored (VBM), Variants of Interest (VOI), Variants of Concern (VOC) and Variants of High Consequence (VOHC). So far, no variants in the US have been identified as VOHC or VOI. Currently, the most common variant in the US is the Delta variant (which includes the B.1.617.2 and AY viral lineages), and it is classified as a VOC.

The Delta variant originated in India and spread rapidly across the UK before making its way into the US (1). Current vaccines, including mRNA and adenoviral vector vaccines, have demonstrated effectiveness against the Delta variant. However, it is a VOC because it is more than twice as contagious as previous variants, and some studies have shown that it is associated with more severe symptoms.

A recent study (2) provides one explanation for the higher infectivity of the Delta variant, using an approach based on virus-like particles (VLPs). The research team was led by Dr. Jennifer Doudna, 2020 Nobel Prize winner for her work on CRISPR-Cas9 gene editing, and Dr. Melanie Ott, director of the Gladstone Institute of Virology at the University of California–Berkeley.

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Illuminating the Kinome: NanoBRET Target Engagement Technology in the Spotlight

Posted on by Ken Doyle

Updated November 21, 2023

In the life of a cell, phosphorylation of proteins is an everyday occurrence. The transfer of a phosphate group, from a molecule such as adenosine triphosphate (ATP) to a specific functional group on a protein, is catalyzed by a protein kinase. The vast majority of protein kinases are classified as either serine/threonine kinases or tyrosine kinases; over 500 kinase genes have been identified in the human genome (1).

nanobret-Target-Engagement-1024x512-1

Protein phosphorylation is a key step in most cell signaling pathways, in response to external or internal stimuli, and it is not surprising that dysregulation of these pathways contributes to a variety of cancers. The first oncogene to be characterized was SRC, a gene that encodes a tyrosine kinase (reviewed in 2). With more kinases being implicated in oncogenic pathways, significant drug discovery efforts have been devoted to developing and characterizing inhibitors of protein kinases. These efforts have accelerated ever since the first targeted small-molecule kinase inhibitor, imatinib, received US FDA approval in 2001 for the treatment of chronic myeloid leukemia (3). Since that time, many more protein kinase inhibitors have received FDA approval, with 67 small-molecule inhibitors listed as of September 2021.

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