Cell Based Assays

Visualize Protein:Protein Interactions with Bioluminescence Imaging

Posted on by Simon Moe

If you’re familiar with bioluminescence, you’ve probably used it in plate-based experiments to track various biological processes. You understand it provides distinct advantages over traditional fluorescence assays, particularly when it comes to sensitivity. However, there’s always that one nagging question: how representative is the signal on a cell-to-cell level?

Traditional approaches to decipher cell-to-cell signal rely on complex, time-intensive measures that only approximated the findings acquired through bioluminescence. That’s where the GloMax® Galaxy Bioluminescence Imager comes in. This new tool will enhance your ability to visualize proteins using NanoLuc® technology, going beyond simple numeric outputs to reveal what’s happening in individual cells.

NanoLuc® technology is well-known for its ability to assist in detecting subtle protein interactions in complex biological systems. This bright luminescent enzyme enables a much broader linear range than fluorescence, improving detection of small changes in protein activity, such as proteins interacting. Microplate readers measuring NanoLuc® assays rely on signal generated from many cells. This results in an approximation of what is occurring biologically. Truly validating those luminescent readings within a cell population has been challenging—until now. The GloMax® Galaxy allows you to perform bioluminescence imaging, moving beyond the numbers, offering the power to visualize protein interactions directly.

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Immunometabolism: The Dynamic Interplay of Cytokines and Metabolites

Posted on by Kendra Hanslik

Immunometabolism is the study of how metabolic processes influence immune cell functions and how immune responses, in turn, shape cellular metabolism. This field examines the roles of cytokines and metabolites, which act as signaling molecules and energy sources, respectively. Cytokines can trigger or modulate metabolic pathways in immune cells, affecting their activation, growth, and response capabilities. Similarly, metabolites provide the necessary energy and building blocks that enable immune cells to proliferate, function optimally, and sustain their activity during immune responses. This dynamic interplay is crucial for maintaining health and combating disease. Together, cytokines and metabolites orchestrate a complex network that links metabolic health with immune competence on a systemic and cellular level. This blog discusses how cytokines and metabolites not only influence but also drive immune cell functions, revealing new avenues for therapeutic interventions across a range of diseases.

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Rethinking Cell Proliferation Assays

Posted on by Simon Moe

In the field of cancer research, accurately measuring cell proliferation is crucial for assessing the efficacy of therapeutic agents. This is particularly difficult with CDK 4/6 inhibitors, which arrest cells in the G1 phase without stopping their growth. This continued growth can skew results from proliferation assays which rely on factors that naturally scale with cell growth. These include mitochondrial activity (ATP levels), total cell protein, or mRNA as measured through the PRISM molecular barcoding strategy. Even though these cells are not dividing, the increase in these measurements can misleadingly suggest active proliferation.

There is growing awareness among researchers of these challenges.  A recent study highlights these limitations by demonstrating the discrepancies that arise when using metabolic assays to assess cell proliferation after treatment with drugs that induce cell cycle arrest. This blog post delves into the study’s implications and demonstrates how one of Promega’s latest developments is poised to address these challenges.

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Decoding the NAD+/NADH Ratio and Its Crucial Role in Cell Health

Posted on by Kendra Hanslik

Nicotinamide adenine dinucleotide (NAD) exists in two forms in the cell: NAD+ (oxidized) and NADH (reduced). This molecule plays a pivotal role in metabolic processes, serving as a key electron carrier in the redox reactions that drive cellular metabolism. The balance between these two forms, commonly expressed as the NAD+/NADH ratio, is crucial for maintaining cellular function and the intracellular redox state. This article explores the significance of this ratio, how it impacts cellular processes, and the consequences of NAD+/NADH ratio dysregulation.

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Connecting Synaptic Gene Polymorphisms to Parkinson’s Disease

Posted on by Kendra Hanslik
alt="synapse"

Neurodegenerative disorders represent a significant and growing concern in the realm of public health, particularly as global populations age. Among these, Parkinson’s disease (PD) stands out due to its increasing prevalence and profound impact on individuals. Characterized by the progressive degeneration of motor functions, PD is not just a health challenge but also poses substantial socio-economic burdens. While the etiology of Parkinson’s disease is far from simple, current research efforts elucidating its causes, mechanisms, and potential treatments illustrate the critical nature of this neurodegenerative disorder in today’s healthcare landscape.

In the clinic, Parkinson’s disease is often diagnosed as either sporadic or familial. Familial PD has a clear genetic basis, typically passed down through families, while sporadic PD, comprising about 90% of cases, occurs in individuals without a known family history of the disease. The exact cause of sporadic PD is not fully understood but is believed to be due to a combination of genetic predispositions and environmental factors. In contrast, the factors involved in familial PD are more thoroughly understood, offering insights into the molecular mechanisms underlying PD pathogenesis.

Polymorphisms and Parkinson’s Disease Susceptibility

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Cell-Based Target Engagement and Functional Assays for NLRP3 Inhibitor Profiling Help Identify Successes and Failures

Posted on by Kari Kenefick

Identifying Inflammasome Inhibitors: What’s Missing
The NLRP3 inflammasome is implicated in a wide range of diseases. The ability to inhibit this protein complex could provide more precise, targeted relief to inflammatory disease sufferers than current broad-spectrum anti-inflammatory compounds, potentially without side effects.

Studies of NLRP3 inflammasome inhibitors have relied on cell-free assays using purified NLRP3. But cell-free assays cannot assess physical engagement of the inhibitor and target in the cellular micro-environment. Cell-free assays cannot show if an NLRP3 inhibitor enters the cell, binds the target and how long the inhibitor binding lasts.

Cell-based assays that interrogate the physical interaction of the NLRP3 target and inhibitor inside cells are needed.

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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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Save Precious Time with Same-Well Multiplexing

Posted on by AnnaKay Kruger
Scientist performing a multi-well assay. Same-well multiplexing enables you to look at one event from several perspectives.

A graduate student believes he has mastered the art of “the assay”. No need to run duplicates, he knows exactly which one will get him the answers he needs right away.  

To challenge this, his PI proposes an exercise. He asks of the graduate student, “What happens when you treat cells with doxorubicin?”

The graduate student raises his cells, treats them accordingly, and decides to run a cell viability assay to determine their fate. He returns to the PI with the final verdict: his cells are dead.

The PI takes a look at the data and asks the graduate student to repeat the experiment with an additional assay for cytotoxicity―but the cytotoxicity assay shows that the cell membranes are intact, which only puzzles the graduate student. The PI asks him to run a third assay for apoptosis, and when the student does so, it becomes clear that the cells are dying.

The PI uses this opportunity to make his point: “Now do you see why I ask for more than one assay?”

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3D Cell Culture Models: Challenges for Cell-Based Assays

Posted on by Isobel Maciver
3D Cell Culture Spheroid
3D Cell Culture Spheroid

In 3D cell culture models, cells are grown under conditions that allow the formation of multicellular spheroids or microtissues. Instead of growing in a monolayer on a plate surface, cells in 3D culture grow within a support matrix that allows them to interact with each other, forming cell:cell connections and creating an environment that mimics the situation in the body more closely than traditional 2D systems. Although 3D cultures are designed to offer a more physiologically accurate environment, the added complexity of that environment can also present challenges to experimental design when performing cell-based assays. For example, it can be a challenge for assay reagents to penetrate to the center of larger microtissues and for lytic assays to disrupt all cells within the 3D system.

Earlier this week Terry Riss, a Senior Product Specialist at Promega, presented a Webinar on the challenges of performing cell-based assays on microtissues in 3D cell culture. During the Webinar, Terry gave an overview of the different methods available for 3D cell culture, providing a description of the advantages of each. He then discussed considerations for designing and optimizing cell-based  assays for use in 3D culture systems, providing several  recommendations to keep in mind when performing cell viability assays on larger microtissue samples.

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Maximize Your Time in the Lab: Improve Experimental Reproducibility with Thaw-and-Use Cells

Posted on by Michele Arduengo

Many cell biology researchers can name their department’s  or institutions’s “cell culture wizard”—the technician with 20+ years of experience whose cell cultures are always free from contamination, exhibit reliable doubling rates and show no phenotype or genotype weirdness. Cell culture takes skill and experience. Primary cell culture can be even more difficult still, and many research and pharmaceutical applications require primary cells.

Yet, among the many causes of failure to replicate study results, variability in cell culture stands out (1). Add to the normal challenges of cell culture a pandemic that shut down cell culture facilities and still limits when and how often researchers can monitor their cell culture lines, and the problem of cell culture variability is magnified further.

Treating Cells as Reagents

A good way to reduce variability in cell-based studies is to use the thaw-and-use frozen stock approach. This involves freezing a large batch of “stock” cells, then performing quality control tests to ensure they respond appropriately to treatment. Then whenever you need to perform an assay, just thaw another vial of cells from that batch and begin your assay—just like an assay reagent! This approach eliminates the need to grow your cells to a specific stage, which could take days and introduce more variability.

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