Center for Metabolic and Liver Diseases Archives - Sanford Burnham Prebys

Tag: Center for Metabolic and Liver Diseases

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A monster, MASH

AuthorGreg Calhoun
Date

January 28, 2025

3D illustration of liver cancer
3D illustration of liver cancer.

Scientists show how the advanced form of fatty liver disease has monstrous effects on liver cancer risk

Liver cancer has proven to be a tough beast to tame. Experts expected rates of the cancer to decrease following the development of the hepatitis B vaccine in the 1980s, which reduced one of the major risk factors for the disease.

Research in Taiwan showed that its universal infant hepatitis B vaccination program led to young adults experiencing a 35.9% reduction in cases of hepatocellular carcinoma (HCC), the most common liver cancer.

Despite innovation leading to the world’s first cancer-preventing vaccine, incidence of HCC has been on the rise due to a spike in fatty liver disease over recent decades. Lifestyle factors such as high-calorie diets, excessive alcohol consumption and minimal exercise — along with genetic predispositions — can lead to problematic changes in the liver, heart and kidneys.

Specifically in the liver, growing deposits of fat in the tissue can lead over time to an advanced form of fatty liver disease marked by chronic inflammation and the accumulation of thickened scar tissue, a condition known as metabolic-associated steatohepatitis (MASH). MASH significantly increases a patient’s risk of developing HCC.

Debanjan Dhar, PhD, headshot outside

Debanjan Dhar, PhD, is an associate professor in the Cancer Genome and Epigenetics Program.

In a paper published January 1, 2025, in Nature, scientists at Sanford Burnham Prebys, the University of California San Diego, Curtin University, the University of Pennsylvania and The Liver Cancer Collaborative, demonstrated that MASH damages the DNA of liver cells. The study also linked these changes to the development of liver cancer.

Peter Adams profile photo in lab

Peter Adams, PhD, is the director of the Cancer Genome and Epigenetics Program.

“DNA damage from MASH causes liver cells to stop dividing and enter a zombie-like state called senescence,” said Debanjan Dhar, PhD, associate professor in the Cancer Genome and Epigenetics Program at Sanford Burnham Prebys and coauthor on the study. “This study’s results demonstrate that some of these cells later exit senescence and are likely to become cancerous due to their accumulation of damage and mutations.”

“In the future, we can apply what we’ve learned to study potential opportunities to prevent or repair DNA damage from MASH to reduce patients’ risk of developing liver cancer,” said Peter Adams, PhD, director of the Cancer Genome and Epigenetics Program at Sanford Burnham Prebys and coauthor on the study.

Michael Karin, PhD, Distinguished Professor in the Department of Pharmacology at the University of California San Diego School of Medicine, is the senior and corresponding author on the study.   

Li Gu, PhD, a former postdoctoral fellow in the Karin lab, shares first authorship of the study with visiting scientist Yahui Zhu. 

Additional authors include:

  • Marcos Teneche and Souradipta Ganguly from Sanford Burnham Prebys
  • Shuvro Nandi, Maiya Lee, Kosuke Watari, Breanna Bareng, Masafumi Ohira, Yuxiao Liu, Sadatsugu Sakane, Mojgan Hosseini, Tatiana Kisseleva, Ludmil Alexandrov, Consuelo Sauceda and David Gonzalez from the University of California San Diego
  • Rodrigo Carlessi and Janina Tirnitz-Parker from Curtin Universit
  • The Liver Cancer Collaborative
  • M. Celeste Simon from the University of Pennsylvania
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Bile may be key to immunotherapy effectiveness in liver cancer

AuthorGreg Calhoun
Date

January 17, 2025

A 3D illustration of hepatocellular carcinoma
A 3D illustration of hepatocellular carcinoma, the most common liver cancer.

Understanding the crucial ingredient in bile may unlock the potential of treatments that help patients’ immune systems eliminate cancer

Hepatocellular carcinoma (HCC) is the most common liver cancer and a growing threat to public health across the globe due to the rising rate of fatty liver disease.

Liver cancer is difficult to treat as it often causes few if any symptoms early on, so it tends to be diagnosed at later, more aggressive stages. While immunotherapies that supercharge patients’ immune systems have proven effective in some cancers, this approach has had limited success in patients suffering from HCC or other forms of the disease.

Scientists are investigating the unique qualities of different tissues that may explain why the effectiveness of immunotherapy varies depending on the location of a tumor. The liver is known to have a flexible immune system capable of defending itself when necessary while not overreacting to a constant flood of foreign materials from digesting food, including metabolic byproducts from bacteria residing in the gut microbiome.

Transplant surgeons see the unique properties of the liver’s immune system firsthand when transplanted livers are typically integrated by recipients with only a low dose of immunosuppressive drugs. This ability to maintain immune tolerance, however, may reduce the ability of the liver’s immune system to find and destroy cancer cells, even when that capability is enhanced by immunotherapy.

In a paper published January 9, 2025, in Science, scientists at Sanford Burnham Prebys, the Salk Institute, the University of California San Diego, Columbia University Irving Medical Center, Memorial Sloan Kettering Cancer Center and the Geisel School of Medicine at Dartmouth, found that a critical ingredient in bile hinders the liver’s immune response against cancer.

Bile is a fluid made by the liver that assists in breaking down fats during digestion. This function is made possible by steroidal acids known as bile acids. The scientists found an increased amount of bile acids in tumor samples from patients with HCC. The team also found that genes involved in creating bile acids were being transcribed to make proteins and enzymes at an abnormally high rate in human samples and in mice genetically modified to develop liver cancer.

The authors went on to remove genes related to bile acid construction to demonstrate that mice without these blueprints developed fewer, smaller tumors. In addition, the liver’s T cells — the primary anti-tumor immune cells — were able to dig deeper into tumors and persist for longer without the immunosuppressive effects of certain bile acids.

“These findings underscore a new appreciation for the influence of bile acids on the liver’s immune system,” said Debanjan Dhar, PhD, associate professor in the Cancer Genome and Epigenetics Program at Sanford Burnham Prebys and coauthor on the study. More research is needed to test the potential use of drugs to directly inhibit certain bile acids or bile acid receptors as a therapeutic strategy to reduce liver cancer growth.

Debanjan Dhar, PhD, headshot outside

Debanjan Dhar, PhD, is an associate professor in the Cancer Genome and Epigenetics Program at Sanford Burnham Prebys.

Peter Adams profile photo in lab

Peter Adams, PhD, is the director of the Cancer Genome and Epigenetics Program at Sanford Burnham Prebys.

It may also be possible to achieve this effect through dietary changes that alter the microbiome and result in modified bile acid production. Based on their findings, the research team suggests that this could be done by using ursodeoxycholic acid, a bile acid that currently is used to treat an autoimmune condition called primary biliary cholangitis. The acid is found at high levels in bear bile, which has served for thousands of years as a treatment in traditional Chinese medicine.

“Given the safety profile of ursodeoxycholic acid and the limited effectiveness of immunotherapy on liver cancer, this study shows significant potential for testing this bile acid as a combination treatment for patients with HCC,” said Peter Adams, PhD, director of the Cancer Genome and Epigenetics Program at Sanford Burnham Prebys and coauthor on the study.

Susan Kaech, PhD, NOMIS Chair, professor and director of the NOMIS Center for Immunobiology and Microbial Pathogenesis at the Salk Institute is the senior and corresponding author on the study.   

Siva Karthik Varanasi, PhD, assistant professor at the UMass Chan Medical School and a former postdoctoral fellow in the Kaech lab at the Salk Institute, is first author on the manuscript. 

Additional authors include:

  • Souradipta Ganguly, Marcos G. Teneche and Aaron Havas, from Sanford Burnham Prebys
  • Dan Chen, Melissa A. Johnson, Kathryn Lande, Michael A. LaPorta, Filipe Araujo Hoffmann, Thomas H. Mann, Eduardo Casillas, Kailash C. Mangalhara, Varsha Mathew, Ming Sun, Yagmur Farsakoglu, Timothy Chen, Bianca Parisi, Shaunak Deota, H. Kay Chung, Satchidananda Panda, April E. Williams and Gerald S. Shadel, from the Salk Institute
  • Yingluo Liu, Cayla M. Miller, Jin Lee and Gen-Sheng Feng, from the University of California San Diego
  • Isaac J. Jensen and Donna L. Farber, from Columbia University Irving Medical Center
  • Andrea Schietinger from Memorial Sloan Kettering Cancer Center
  • Mark S. Sundrud from the Geisel School of Medicine at Dartmouth

Wolfram Goessling, MD, PhD, the Robert H. Ebert Associate Professor of Medicine and associate professor of Health Sciences and Technology at Harvard Medical School, authored a Perspective article on the new study in Science called, “Ena-bile-ing liver cancer growth.”

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Common gut bacteria have a taste for tungsten

AuthorGreg Calhoun
Date

January 9, 2025

Dmitry Rodionov profile photo
Dmitry A. Rodionov, PhD, is a research assistant professor in the Immunity and Pathogenesis Program at Sanford Burnham Prebys.

A bacteria linked to longevity was found to feast on lactate only when the meal contains the metallic side dish

In a new paper published December 30, 2024, in PNAS, study coauthor Dmitry A. Rodionov, PhD, research assistant professor in the Immunity and Pathogenesis Program at Sanford Burnham Prebys, and colleagues, studied how Eubacterium limosum contribute to a healthy human gastrointestinal microbiome by metabolizing lactate.

Lactate or lactic acid is a normal byproduct that is created as our cells generate energy. Lactate can be found in the guts of healthy adults at low concentrations because microbes such as E. limosum make a meal of much of it, preventing the abnormal accumulation sometimes found in patients suffering from ulcerative colitis and other gut-related disorders.

Rodionov and his colleagues examined how E. limosum bacteria break down lactate into short-chain fatty acids (SCFAs) and were surprised to find that the metabolic process depends on two tungsten-containing enzymes.

The authors suggest that their findings are a tipoff that tungsten might be an overlooked micronutrient in the human gut microbiome and may contribute in unappreciated ways to overall human health.

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Gut microbiome repair in children with severe acute malnutrition

AuthorScott LaFee
Date

October 2, 2024

child being spoon fed with family in background

Child malnutrition remains an alarming and appalling scourge.

In 2022, according to the World Health Organization, 148 million children in the world under 5 years were too short for their age (stunting) and another 45 million were too thin for their height (wasting) due to inadequate diet and nutrition.

Researchers around the world, including Andrei L. Osterman, PhD, professor in the Immunity and Pathogenesis Program at Sanford Burnham Prebys, have been investigating potential remedies, in particular some of the consequences of malnutrition, such as disturbed metabolism and immune/gut function.

In a new paper published October 2, 2024 in Science Translational Medicine, the multi-institutional team (including Osterman and colleagues at SBP) describe an interventional diet that essentially repairs the gut microbiome in children with moderate to severe acute malnutrition.

They conducted a three-month randomized controlled trial of a specialized food supplement in 12- to 18-month-old Bangladeshi children living in rural and urban slums with moderate acute malnutrition who had already been treated in hospital for severe acute malnutrition. The supplement, called microbiota-directed complementary food or MDCF-2, contains chickpea flour, peanut flour, soy flour, green banana, sugar, soybean oil and a vitamin-mineral premix, a formulation designed to promote the growth of therapeutic gut bacteria and improve the overall health and balance of the gut microbiome.

They found that MDCF-2 improved weight-for-age better than the traditional ready-to-use supplementary food (RUSF) used by relief agencies and others, which is composed of more traditional ingredients like rice, lentil, sugar, soybean oil and skimmed milk powder mixed with vitamins and minerals.

When excluding children unable to continue study participation due to severe flooding during the trial, the study authors also reported improvement of stunting at a faster rate. They tied these improvements in children’s health to Prevotella copri–associated metabolic changes.

P. copri (recently renamed as Segatella copri) is a bacterium found abundantly in the human gastrointestinal microbiome. Past studies have reported both positive and negative associations with health and disease. In the former, for example, healthy bacterial colonization of the gut has been positively correlated with conditions like inflammation, insulin resistance and diarrhea. It appears to be a major player in regulating dietary metabolism.

The bacterium is more common in non-Westernized populations consuming a diet rich in plants—the bacterium’s source of nutrients. In Western populations, it is associated with consumption of fruits and vegetables.

Genomic reconstruction of the metabolic potential of P. copri strains positively associated with infants’ health improvement confirmed their unique ability to utilize a large repertoire of plant-derived polysaccharides comprising MDCF-2 diet.

“This study can be viewed as a test of the generalizability of the efficacy and mechanism of action of MDCF-2 in acutely malnourished children,” said Osterman. “The main findings include the demonstration of significantly higher efficacy of MDCF-2 vs RUSF with respect to the improvement of (weight) growth.

“The success of the treatment was also manifest by beneficial changes in microbiome composition and by global changes of a range of serum protein biomarkers associated with healthy development.”

The findings, he said, also provide proof-of-concept that improving gut microbial health can be achieved using therapeutic nutrition and offers further guidance on how best to use microbiota-directed complementary foods.

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Sanford Burnham Prebys research plays a key role in developing microbiome-directed complementary food to help save malnourished children

AuthorScott LaFee
Date

January 4, 2024

A Bangladeshi mother and child in the Nutritional Rehabilitation Unit of the International Centre for Diarrhoeal Disease Research Hospital in Dhaka.

Among the consequences of childhood malnutrition is the underdevelopment of their gut microbiomes, critical to human health, from innate immunity to appetite and energy metabolism.

Although malnourished children gain some weight and grow better when fed a nutrient-rich diet, they do not catch up to their well-fed counterparts—and their gut microbiomes do not recover.

In a 2021 clinical trial, researchers at Washington University School of Medicine showed how a newly designed therapeutic food—a unique mix of peanuts, bananas and other foods dubbed microbiome-directed complementary food, or MDCF—more effectively nourished healthy gut microbial communities than standard dietary supplements.

Now, with bioinformatics support from Andrei L. Osterman, PhD, professor in the Immunity and Pathogenesis and Cancer Metabolism and Microenvironment programs at Sanford Burnham Prebys  and his colleagues Dmitry Rodionov, PhD, and Alex Arzamasov, the multi-institutional scientific team has published new research that identifies and describes the bioactive elements of microbiome-directed food.

“These are naturally occurring carbohydrate structures that could, in theory, be recovered in large quantities from the by-product streams of food manufacturing and be used to produce prebiotics,” said senior study author Jeffrey I. Gordon, MD, the Dr. Robert J. Glaser Distinguished University Professor at Washington University.

“We also have identified the microbes that process these food components, and in theory, there is potential for the organisms themselves to be part of a therapeutic intervention in children completely lacking these beneficial gut microbes.”

Osterman’s lab contributed bioinformatics analyses of 1,000 new metagenomically assembled genomes, or MAGs, representing the gut microbiomes of healthy Bangladeshi infants. The analyses included genome-based inference of the presence or absence in these MAGs of functional metabolic pathways for 106 major nutrients and intermediary metabolites.

“These predictions enabled the assessment of the microbiome-wide representation or enrichment of dietary carbohydrate utilization capabilities across numerous biospecimens from a randomized, controlled trial of MDCF in Bangladeshi children with moderate acute malnutrition,” said Osterman.

“The analyses helped elucidate glycan components of MDCF metabolized by bacterial taxa that are positively associated with healthy weight growth. The knowledge will help guide the therapeutic use of current MDCF and enable development of new formulations.”

Childhood undernutrition is a global scourge. In 2020, an estimated 149 million children under the age of 5 had stunted growth (low height for age), and 45 million exhibited stunting (low weight for height). More than 30 million children worldwide have moderate, acute malnutrition.

Undernutrition and its consequences are the leading causes of disease and death for children in this age range. An estimated 3 million children die each year due to poor nutrition and hunger.

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Randal J. Kaufman among the world’s most influential scientists

AuthorSusan Gammon
Date

November 15, 2023

Randal J. Kaufman, PhD

Over the last decade, the publications of Randal J. Kaufman are among the top 1% in the world by number of citations

Sanford Burnham Prebys professor Randal J. Kaufman, PhD was included on Clarivate’s 2023 Highly Cited Researchers list, a global ranking of influential researchers based on the number of times their work has been cited in peer-reviewed publication over the last decade. Launched in 2014 by Clarivate, a global research analytics company, the list identifies scientists who have demonstrated exceptional influence in their respective fields.

“The Highly Cited Researchers list identifies and celebrates exceptional individual researchers at Sanford Burnham Prebys who are having a significant impact on the research community as evidenced by the rate at which their work is being cited by their peers,” says David Pendlebury, head of Research Analysis at the Institute for Scientific Information at Clarivate. “These individuals are helping to transform human ingenuity into our world’s greatest breakthroughs – and it is an honor to celebrate their achievements.”

The 2023 list includes 7,125 individuals from 67 countries. With 2,669 American researchers named to the list, the United States had the greatest number of highly cited researchers compared to any other country, representing 37.5 percent of the complete list.

Randal J. Kaufman, PhD  – Discovering how proteins fold

Randal J Kaufman has a legacy of scientific contribution that extends across academia and industry alike. His landmark studies in the 1980’s contributed to the discovery of the unfolded protein response, a ubiquitous cellular stress response that occurs when misfolded proteins accumulate in cells. This response has been associated with an enormous array of human disease, including cancer, neurological, metabolic, genetic and inflammatory disorders, as well as the symptoms associated with aging. Today, his work continues to focus on explaining how and why misfolded proteins contribute to cell malfunctions and death, and his findings continue to shape the research of others through his highly cited publications.

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Randal Kaufman included in $12 million initiative to improve hemophilia treatment

AuthorMiles Martin
Date

March 8, 2022

Randal J. Kaufman, PhD

The new project will help researchers better understanding why current gene therapy treatments aren’t working.

A multi-institute research collaboration including Sanford Burnham Prebys has just received a $12 million grant from the National Heart, Lung, and Blood Institute to improve hemophilia therapy. The award will fund three projects that could lead to safer and potentially curative treatments for the disorder. One of these projects will be led by Randal J. Kaufman, PhD, who directs the Degenerative Diseases Program at Sanford Burnham Prebys.

How viruses could be help treat hemophilia
Hemophilia is an X-linked genetic condition that prevents the blood from clotting properly. It occurs in about one out of 5,000 male births. In patients with severe forms of the disease, internal or external bleeding can be life threatening. Standard treatments for severe hemophilia involve intravenously replacing the clotting proteins that patients are unable to produce adequately on their own. However, a gene therapy approach uses viruses as a delivery mechanism to provide the body with the information it needs to start making its own clotting factors.

“Several companies have taken this forward into clinical trials, and in some of these trials, the patients initially looked like they were cured,” says principal investigator Roland W. Herzog, PhD, the Riley Children’s Foundation Professor of Immunology at Indiana University School of Medicine. “But what they all have in common is that they need to deliver a lot of the virus in order to get the desired results, and over time, clotting factor levels started to decline. So it’s clear that we need to further study the biology of this phenomenon.”

How this grant will help improve the process
In hemophilia A, which accounts for about 80% of all cases, patients do not produce enough of a clotting protein called factor VIII (FVIII). To better understand the mechanisms that are mitigating the effects of current drug candidates, Herzog is teaming up with some of the nation’s leading experts. 

Their program will focus on three major projects in gene therapy for hemophilia A:

  • Project 1 will focus on cellular toxicity and stress that can be induced by FVIII protein production. This project is led by Kaufman. 
  • Project 2 will focus on molecular virology and the development of viral vectors used in gene therapy to deliver the FVIII-encoding gene.This project is led by Indiana University School of Medicine professor of pediatrics Weidong Xiao, PhD
  • Project 3 will examine the immune system and its role in the interference of FVIII production over time. It is jointly led by Herzog and Ype P. de Jong, MD, PhD, assistant professor of medicine at Cornell University. 

Together, they hope to provide new insight that can lead to lower levels of toxicity and improved longevity of FVIII production in patients who are treated with gene therapy for hemophilia.

“This is an incredibly significant and urgent medical question, and it requires the synergy of multiple groups with different expertise to come together and solve a problem that they wouldn’t be able to solve on their own,” says Herzog. “My hope is that our studies will help the field as a whole move toward curing hemophilia A.”

The grant is titled “Toward Safer Gene Therapy for Hemophilia A” (P01HL160472). This post was adapted from a press release published by Indiana University School of Medicine.

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This enzyme is one of the hardest working proteins in the body

AuthorMiles Martin
Date

October 21, 2021

Rendering of a red-orange protein molecule on a black background

Researchers from Sanford Burnham Prebys have shown that a protein they identified plays a major role in the breakdown of hyaluronic acid, a compound found in the scaffolding between our cells. The findings, published recently in the Journal of Biological Chemistry, could have implications for epilepsy, cancer and other human diseases associated with hyaluronic acid and similar compounds.

They also shed light on one of the most active biochemical processes in the body. 

“Our body turns over hyaluronic acid at an extremely rapid rate, far faster than the other compounds surrounding our cells,” says senior author Yu Yamaguchi, MD, PhD, a professor in the Human Genetics Program at Sanford Burnham Prebys.

Hyaluronic acid, a common ingredient in cosmetic anti-aging products, is a one of several large sugar molecules known as glycosaminoglycans (GAGs). These are found naturally in the extracellular matrix, the complex network of organic compounds surrounding our cells that gives structure to our tissues. In addition to its structural role, the extracellular matrix is involved in regulating the immune system and is critical in the early development of connective tissues like cartilage, bone and skin.

“The extracellular matrix is found in every organ and tissue of the body, and malfunctions in its biochemistry can trigger or contribute to a variety of diseases, some of which we don’t even know about yet,” says Yamaguchi. His team studies how GAGs affect childhood diseases including congenital deafness, epilepsy and multiple hereditary exostoses, a rare genetic disorder that causes debilitating cartilage growths on the skeleton.

Hyaluronic acid is also known to be correlated with several health conditions, depending on its concentration in certain tissues. Reduced levels of hyaluronic acid in the skin caused by aging contribute to loss of skin elasticity and reduced capacity to heal without scarring. Levels of hyaluronic acid in the blood dramatically increase in alcoholic liver disease, fatty liver and liver fibrosis. In addition, hyaluronic acid levels have been correlated with increased tumor growth in certain cancers.

“These compounds are literally everywhere in the body, and we continue to learn about how GAG’s influence disease, but there’s also a lot we still don’t know about how these molecules are processed,” says Yamaguchi, “Research like this is about understanding what’s happening at the molecular level so we can later translate that into treatments for disease.” 

For this study, the team focused on a protein called TMEM2, which they had previously found to break down hyaluronic acid by cutting the longer molecule into manageable pieces for other enzymes to process further. Using mice as a research model, they selectively shut off the gene that codes for TMEM2 and were able to successfully measure precisely how much the absence of TMEM2 affects the overall levels of hyaluronic acid.

The answer: a lot.

“We saw up to a 40-fold increase in the amount of hyaluronic acid in the study mice compared to our controls,” says Yamaguchi. “This tells us that TMEM2 is one of the key players in the process of degrading this compound, and its dysfunction may be a key player in driving human diseases.” 

The team further confirmed this role of the TMEM2 protein by using fluorescent compounds that detect hyaluronic acid to determine where the TMEM2 protein is most active. They found the most activity on the surface of cells lining blood vessels in the liver and lymph nodes, which are known to be the main sites of hyaluronic acid degradation. 

“These findings refine our understanding of this critical biochemical process and set us up to explore it further in the interest of developing treatments for human diseases,” says Yamaguchi. “Hyaluronic acid is so much a part of our tissues that there could be any number of diseases out there waiting to benefit from discoveries like these.”

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Scientists discover an early sign of type 2 diabetes: Misfolded proinsulin

AuthorMonica May
Date

March 19, 2020

Diabetic patient is using glucometer to check glucose level

The findings could lead to tests or treatments that help prevent type 2 diabetes.

Misfolded proinsulin—a protein the body normally processes into insulin—is an early sign of type 2 diabetes, according to a study by scientists at Sanford Burnham Prebys and the University of Michigan Medical School. The discovery, published in eLife, could lead to tests or treatments that help prevent people from developing type 2 diabetes.

“Understanding the molecular events that occur as prediabetes progresses to diabetes opens new avenues for us to detect or interrupt these processes,” says Randal Kaufman, PhD, director and professor in the Degenerative Diseases Program at Sanford Burnham Prebys and co-corresponding author of the study. “With this information, we can start to find interventions that might spare millions of people from a serious, lifelong condition.”

More than one in three Americans, or approximately 88 million people, have prediabetes—which is characterized by elevated blood sugar. If left untreated, within four years nearly 40% of people with prediabetes develop type 2 diabetes, which occurs when the body doesn’t use insulin properly. In 2017, the cost of treating diabetes exceeded $327 billion, according to the American Diabetes Association. Due to increasing obesity rates, the number of people with the condition—particularly children—is on the rise.

Identifying the molecular events that occur during progression from prediabetes to full-blown diabetes remains one of the most perplexing problems in diabetes research. In the study, the scientists set out to answer this question by tracking proinsulin folding in the beta cells of humans and mice that are healthy, prediabetic and diabetic.

These studies revealed that instead of undergoing its normal folding process, proinsulin proteins were abnormally linked to each other. Levels of the abnormal proinsulin accumulated as prediabetes progressed to type 2 diabetes. Obese mice in the earliest stages of diabetes had the highest levels of abnormal proinsulin in their beta cells.

“Proinsulin misfolding is the earliest known event that may contribute to the progression from prediabetes to diabetes,” says Kaufman. “Together, these studies show that abnormally linked proinsulin holds promise as a potential measure of how close someone may be to developing type 2 diabetes.”

Now, the researchers are set to uncover more details about this process, such as the proteins that interact with the misfolded proinsulin.

“Understanding the fundamental molecular events that lead to type 2 diabetes is critical as the number of people with prediabetes continues to rise,” says Kaufman. “If we don’t find preventive measures, we will soon have a diabetes epidemic.”

The study’s first author is Anoop Arunagiri, PhD; and the study’s senior author is Peter Arvan, both of the University of Michigan Medical School.

Additional authors include Leena Haataja and Fawnnie Pamenan of the University of Michigan Medical School; Ming Liu of the University of Michigan Medical School and Tianjin Medical University in China; Anita Pottekat and Pamela Itkin-Ansari of Sanford Burnham Prebys; Soohyun Kim of Konkuk University in South Korea; Lori M. Zeltser of Columbia University; Adrienne W. Paton and James C. Paton of the University of Adelaide in Australia; and Billy Tsai of the University of Michigan.

The study’s DOI is 10.7554/eLife.44532.

This work was supported by the National Institutes of Health (R01DK111174, R24DK110973 and R01DK48280) and the Juvenile Diabetes Research Foundation International (2-SRA-2018-539-A-B).