Cell Biology

Jon Campbell Is Challenging Classic Models of Metabolic Disease

Posted on by Jordan Villanueva

Jonathan Campbell, PhD, asked me to write that he is taller and a bit more handsome than most scientists. I will neither confirm nor deny those assertions, but I will acknowledge that Dr. Campbell has a unique way of describing his recent collaborations and research on metabolism and Type 2 diabetes.

“The rest of the world has been thinking that it’s almost like the emperor has no clothes,” he says. “But we’re the guys who came right in and said ‘Hm, that dude’s naked.’”

Lumit Immunoassays give Jon Campbell's lab better results with an easier workflow.

On March 13, only a few days before the COVID-19 pandemic caused widespread shutdowns in Wisconsin, Jon visited the Promega headquarters in Madison, Wisconsin to meet with R&D scientists and discuss opportunities for new technologies. Over the course of a few hours, Jon and his collaborator Matthew Merrins, PhD, demonstrated how their research challenges dogma and could fundamentally change our understanding of postprandial metabolism. For five decades, the paradigm of glucose control focused on a model that positioned insulin and glucagon as diametrically opposing forces to raise or lower glycemia. As Jon states, things did not always add up.

“For years, everybody has been saying ‘Glucagon is the antithesis of insulin,’ right? Insulin is a good guy. It makes glucose come down. Glucagon is a bad guy. It makes glucose go up. And these two are in this cosmic battle against each other over the control of glycemia. Well, we asked, ‘Why do the beta cells that secrete insulin have glucagon receptors?’ And as you follow the breadcrumbs, you find that these two things are actually working in cooperation. Without that cooperation, the whole thing falls apart,” Jon says.

The Incretin Effect

In addition to exploring the complex biology of glucagon, Jon’s lab studies the Incretin Effect, a mechanism by which the gut influences the secretion of insulin in the pancreas. Past research revealed that rises in blood-glucose matched closely whether glucose was administered orally or intravenously. However, the amount of insulin secreted was 3—4 times higher following oral intake. This is a result of the actions of GLP1 and GIP, the two major human incretins. GLP1 and GIP bind to G-protein coupled receptors in the beta cells of the pancreas to induce insulin secretion. Insulin then acts to promote glucose uptake, reducing glycemia. Many researchers believe that dysfunction of the incretin mechanisms contributes to the reduced insulin secretion seen in individuals with Type 2 diabetes.

“If we can understand the mechanisms of the incretin effect,” Jon says, “We may be able to understand the pathophysiology driving Type 2 diabetes. My hope is that people are going to realize that diabetes is not just a glucose disease. Maybe we have been looking at this too much from a glucose-centric viewpoint. Clearly, glucose is a big problem with diabetes, but it’s not just glucose. This is a metabolic disease, and in order to understand how to fix a metabolic disease, you need to look at all the metabolites and the way overall metabolism is dysregulated.”

Research on the incretin effect has already supported the development of two new classes of drugs for Type 2 diabetes: GLP1R agonists and DPP4 inhibitors (DPP4 is an enzyme that degrades GLP1).

“We collaborate with industry quite a bit, especially pharmaceuticals. We are helping them understand the mechanism of action by which their drugs may work, and that funding has allowed us to expand and grow our program a lot in our first five years. I like to bridge that line between basic and translational science—translating basic science into the clinic.”

The Search for New Technology

Jon wasn’t visiting Promega in mid-March with the goal of seeing the world before COVID-19-related travel restrictions were announced. He’s constantly looking for new collaborations in which both parties can bring something unique to the table. Jon was one of the first to try the new Lumit™ Insulin and Glucagon Immunoassays, which he says are easier to use and have produced better results in his work with glucagon than radioimmunoassays or ELISAs.

“People like Promega scientists say they have a new technology, and they’re looking for someone to try it out it in real-world situations. I don’t have that kind of technology, but I know how to apply it, so there’s a lot of value there. It’s a no-brainer to talk to people about how we can find synergy when the two of us both bring something like that to the table. For some applications, the Lumit™ assays are blowing out whatever we can do, and they’re also incredibly easy to use. So that was a significant improvement in our workflow.”

When asked what he hopes to accomplish in the next few years, Jon similarly points to innovative technology and techniques.

“We have to say, ‘What’s the next innovative step forward, and what new tools can we bring?’ We need to figure out new ways to interrogate the systems that we’re interested in. Then we can start to strip away new biology. If we ask the right question and we answer definitively, we’ll end up with three more questions. Which is great, because we’ll always have more work to do.”

Lumit™ Immunoassays provide a simple and fast alternative to conventional immunoassay methods including sandwich ELISAs and Western blots. Learn more here.

Working on diabetes research? Read more about Promega assays to measure insulin activity in real time.

CRISPR/Cas9 HiBiT Knock-In: A Scalable Approach for Studying Endogenous Protein Dynamics

Posted on by Darcia Schweitzer

Studying protein function in live cells is limited by the tools available to analyze the expression and interactions of those proteins. Although mass spectrometry and antibody-based protein detection are valuable technologies for protein analysis, both methods have drawbacks that limit the range of targets and contexts in which proteins can be investigated.

Mass spectrometry is often poor at detecting low-abundance proteins. Antibody-based techniques require high quality, specific antibodies, which can be difficult to impossible to acquire. Both methods require cell lysis, preventing real-time analysis and limiting the physiological relevance, and both methods can be limiting for higher-throughput analysis. While plasmid-based overexpression of tagged target proteins simplifies detection and can allow for real time analysis, protein levels don’t typically resemble endogenous levels. Overexpression also has the potential to create experimental artifacts or limit the dynamic range of an observed response.

In 2018, Promega R&D scientists published a paper in ACS Chemical Biology demonstrating the use of CRISPR/Cas9 to integrate the 11 amino acid, bioluminescent HiBiT tag directly into the genome to serve as an easily measured reporter for endogenous proteins. This provides a highly quantitative method for investigating cellular protein dynamics that sidesteps the need for cloning and other drawbacks to conventional methods, including the ability to measure changing protein dynamics in real-time. (For more details about CRISPR/Cas9 knock-in tagging and other applications, read this blog.)

While their findings showed that this method provides efficient and specific tagging of endogenous proteins, the research was limited to just five different proteins within a single signaling pathway in two cell lines. This left unanswered questions about whether this approach was scalable, had broader applications and how accurately the natural biology of the cells was represented.

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The Surprising Landscape of CDK Inhibitor Selectivity in Live Cells

Posted on by Promega

Cyclin-dependent kinases (CDKs) are promising therapeutic targets in cancer and are currently among the most intensely studied enzymes in drug discovery. The FDA has recently approved three drugs for breast cancer that target members of this kinase subfamily, fueling interest in the entire family. Although broad efforts in drug discovery have produced many CDK inhibitors (CDKIs), few have been characterized in living cells. So just how potent are these compounds in a cellular environment? Are these compounds selective for their intended CDK target, or do they bind many similar kinases in cells? To address these questions, teams at the Structural Genomics Consortium and Promega used the NanoBRET™ Target Engagement technology to uncover surprising patterns of selectivity for touted CDKIs and abandoned clinical leads (1). The results offer exciting opportunities for repurposing some inhibitors as selective chemical probes for lesser-studied CDK family members.

CDKs and CDKIs

nanobret technology for kinase target engagement

Cyclin-dependent kinases (CDKs) regulate a number of key global cellular processes, including cell cycle progression and gene transcription. As the name implies, CDK activity is tightly regulated by interactions with cyclin proteins. In humans, the CDK subfamily consists of 21 members and several are validated drivers of tumorigenesis. For example, CDKs 1, 2, 4 and 6 play a role in cell cycle progression and are validated therapeutic targets in oncology. However, the majority of the remaining CDK family is less studied. For example, some members of the CDK subfamily, such as CDKs 14–18, lack functional annotation and have unclear roles in cell physiology. Others, such as the closely related CDK8/19, are members of multiprotein complexes involved broadly in gene transcription. How these kinases function as members of such large complexes in a cellular context remains unclear, but their activity has been associated with several pathologies, including colorectal cancer. Despite their enormous therapeutic potential, our knowledge of the CDK family members remains incomplete.

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ADCC and Fc Effector Functions: Considerations for COVID-19 Vaccine Development

Posted on by Jordan Villanueva

As we continue navigating the challenges presented by COVID-19, several research areas are crucial for helping us slow the infection rate and ending the pandemic. Advanced testing methods, such as antibody testing, help us understand and predict how the virus will spread, which can inform policy decisions. Effective therapeutics will influence clinical outcomes for individual patients, and several drugs are already being tested or administered. However, an effective vaccine against the SARS-CoV-2 virus is perhaps the most important tool we can use to protect individuals and populations from COVID-19.

Over 90 vaccines against the SARS-CoV-2 virus are currently in development around the world. While there are many different types of vaccines, the overall goal is to create long-lasting protective immunity by stimulating the production of specific antibodies. As these vaccine candidates are further characterized, monitoring ADCC activity can provide important insights into their potential efficacy.

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Illuminating the Function of a Dark Kinase (DCLK1) with a Selective Chemical Probe

Posted on by Promega

The understudied kinome represents a major challenge as well as an exciting opportunity in drug discovery. A team of researchers lead by Nathanael Gray at the Dana Farber Cancer Institute was able to partially elucidate the function of an understudied kinase, Doublecortin-like kinase 1 (DCLK1), in pancreatic ductal adenocarcinoma cells (PDAC). The characterization of DCLK1 in PDAC was realized by developing a highly specific chemical probe (1). Promega NanoBRET™ Target Engagement (TE) technology enabled intracellular characterization of this chemical probe.

The Dark Kinome

NanoBRET target engagement

Comprised of over 500 proteins, the human kinome is among the broadest class of enzymes in humans and is rife with targets for small molecule therapeutics. Indeed, to date, over 50 small molecule kinase inhibitors have achieved FDA approval for use in treating cancer and inflammatory diseases, with nearly 200 kinase inhibitors in various stages of clinical evaluation (2). Moreover, broad genomic screening efforts have implicated the involvement of a large fraction of kinases in human pathologies (3). Despite such advancements, our knowledge of the kinome is limited to only a fraction of its family members (3,4). For example, currently less than 20% of human kinases are being targeted with drugs in clinical trials. Moreover, only a subset of kinases historically has garnered substantial citations in academic research journals (4). As a result, a large proportion of the human kinome lacks functional annotation; as such, these understudied or “dark” kinases remain elusive to therapeutic intervention (4).

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Targeting IL-6: How A Drug That Helped a 6-Year-Old Beat Cancer Can Save COVID-19 Patients

Posted on by Johanna Lee

In 2012, a 6-year-old girl named Emily Whitehead was battling acute lymphoblastic leukemia (ALL), one of the most common cancers in children. Her cancer was stubborn. After 16 months of chemotherapy, the cancer still would not go into remission. There was nothing else the doctors could do, and she was sent home. She was expected to survive only a few more months. Her parents would not give up and enrolled her into a clinical trial of a new immunotherapy treatment called chimeric antigen receptor (CAR) T cell therapy. She was the first pediatric patient in the program.

Doctors took T cells from Emily’s blood and reprogrammed them in a lab. They essentially sent her T cells to boot camp where they are trained to find cancer cells and destroy them. The reprogrammed T cells were then injected back into her body. A week into treatment, she started getting a fever, the first sign that the treatment was working and her reprogrammed T cells were fighting the cancer. But soon, she got very sick. All of the indicators suggested that she had cytokine release syndrome (CRS)—also known as the cytokine storm. This happens when cytokines are released in response to an infection but the process cannot be turned off. The cytokines continue to attract immune cells to the infection site, causing damage to the patient’s own cells and eventually resulting in acute respiratory distress syndrome (ARDS). (Learn more about the cytokine storm in this blog.)

Emily was soon on a ventilator. Tests showed that she had extremely high levels of one particular cytokine: interleukin-6 (IL-6). Desperate to keep her alive, her doctors gave her a known drug that specifically targets IL-6. The results were dramatic. After one single dose, her fever subsided within hours, and she was taken off the ventilator. On May 2nd, 2012, she woke up from an induced coma—it was her 7th birthday. Her doctors said they have never seen a patient that sick get better that quickly.

The drug that saved her life was tocilizumab.

Continue reading “Targeting IL-6: How A Drug That Helped a 6-Year-Old Beat Cancer Can Save COVID-19 Patients”

The Cytokine Storm: Why Some COVID-19 Cases Are More Severe

Posted on by Johanna Lee
coronavirus

Blog Updated on June 16, 2020

One of the biggest outstanding questions of the COVID-19 pandemic is why symptoms vary so much among patients. Some patients have no symptoms at all; some symptoms are mild, while others are extremely severe. Among the more severe cases, a common pattern of disease progression happens like this: A patient gets through the first week with some signs of recovery—then suddenly they rapidly deteriorate. In some cases, they go from needing just a tiny bit of oxygen to requiring a ventilator within 24 hours.

This pattern, often seen in young and otherwise healthy patients, has baffled doctors. What causes these patients to suddenly crash? Research now suggests that the patient’s own immune system may be to blame. It’s called cytokine release syndrome—also known as the “cytokine storm”.

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Fighting the COVID-19 Pandemic With Antibody Testing: The Importance of Serological Assays

Posted on by Promega

Today’s blog is written by Ashley G. Anderson, MD, Chief Medical Officer at Promega.

The need for reliable virus detection methods is central to the global response to COVID-19. These test results not only inform health decisions for individual patients, but they also help us build projections of how the virus will spread, which can in turn influence policy decisions.

Following the emergence of COVID-19, PCR-based tests were developed and deployed to detect the virus in patients in hospitals. PCR, or Polymerase Chain Reaction, is a common technique used in labs to amplify large quantities of DNA. The detection tests use swabs placed deep into the back of the nose to detect genetic material carried by SARS-CoV-2, the virus causing COVID-19.

Those tests have been crucial to monitoring infection rates and informing patient treatment, but at this point they have fallen short of providing an overall picture of the pandemic. We know that thousands more cases have likely gone untested due to mild or unnoticed symptoms or lack of access to tests. Since PCR-based methods can only tell us if the virus is active in the patient at the time of sample and offer no information about whether a patient has been infected in the past, we currently have no way to determine how many of these unconfirmed cases exist or which patients have recovered. Serological assays are the one of the most promising tools to address that question.

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How the SARS-CoV-2 Coronavirus Enters Host Cells and How To Block It

Posted on by Johanna Lee
TE micrograph of a single MERS-CoV
Photo courtesy of National Institute of Allergy and Infectious Diseases

In December 2019, a new disease emerged from a seafood market in Wuhan, China. People who were infected began experiencing fever, dry cough, muscle aches and shortness of breath. The disease swept through China like wildfire and quickly spread overseas to almost every continent. We now know the virus that caused this disease, SARS-CoV-2, is a member of the severe acute respiratory syndrome coronavirus, and the disease itself was officially named COVID-19. According to the Johns Hopkins University Coronavirus Resource Center, there are 877,422 confirmed cases of COVID-19 worldwide, and 43,537 total deaths at the publication of this blog. Those numbers are only expected to increase over the next few weeks.

In this moment of crisis, scientists all around the world are desperately trying to find ways to treat and prevent the disease. One strategy for preventing the spread of the virus is to block its entry into human cells. But first we need to understand how SARS-CoV-2 enters human cells. A research group at the German Primate Center led by Dr. Stefan Pohlmann provides some answers in a recent publication in Cell.

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Producing Snake Venom— in the Lab

Posted on by Johanna Lee

Snakebite is a serious public health issue in many tropical countries. Every year, roughly 2 million cases of poisoning from snakebites occur, and more than 100,000 people die. Snake venom is extremely complex, containing a cocktail of chemicals, many of which are undefined. This complicates the development of new therapeutics for treating snakebite.

Antivenom is the most effective treatment for snakebites, but its production is complex and dangerous. It involves manually milking the venom from different species of live snakes, then injecting small doses of the venom into animals (mostly horses) to stimulate an immune response. After a period of time, antibodies form in the animal’s blood, which is purified for use as antivenom.

But what if we could produce snake venom in the lab, instead of using live snakes? Recently, a group from the Netherlands did just that by growing organoids derived from snake venom glands.

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