University of Louisville researcher Zhong-bin Deng has received a new grant from the National Institutes of Health to investigate how a high-fat diet contributes to these conditions and identify processes that may reduce liver inflammation and lead to new treatments.

Deng’s previous research revealed mechanisms in which dietary fat causes changes in the structure of epithelial cells, which comprise the lining of the walls of the intestines. When gaps form between these cells, toxins are allowed to move directly from the gut to the liver, where they cause an immune response and inflammation.

Building on this work, Deng, assistant professor in the Division of Immunotherapy within the Department of Surgery in the UofL School of Medicine, has been awarded $2 million from the NIH over five years to further investigate how these toxins cause the immune response in the liver, as well as test interventions that may reduce it.

“We are looking at how a high fat diet affects epithelial cells, allowing toxins to escape the gut and travel to the liver, leading to an immune response by macrophages in the liver and inflammation,” Deng said. “Also, we are trying to find a new therapy that could modulate the gut environment to control fatty liver disease.”

Deng’s research seeks to further understand the mechanism that leads to the gaps in the epithelial cells, which allow toxins produced by bacteria in the gut to move to the liver via the portal vein, known as the gut-liver axis. Deng and his team believe that the toxins cause the immune response of inflammation by changing Kupffer cells, white blood cells that reside in the liver. That inflammation can lead to liver cell damage.

“We propose that gut microbiota or the gut epithelial cells produce a signal that affects the Kupffer cells, causing inflammation in the high fat condition and may damage hepatocytes,” Deng said.

As part of the project, the researchers also will test whether an oligosaccharide found in human breast milk can be used to regulate the gut environment and mitigate the impact of the high fat diet on liver inflammation.

“We are trying to find out how to regulate this macrophage condition from an inflammation condition to an anti-inflammation condition,” Deng said.

“Dr. Deng’s new research evaluates highly novel aspects of nutrition in NAFLD,” said Craig McClain, professor and associate vice president for health affairs/research at UofL.

Jun Yan, director of the Division of Immunotherapy, said the research may lead to increased understanding of the causes of liver cancer.

“The research findings from this grant may also help understand how this type of liver inflammation leads to hepatocellular carcinoma, which causes approximately 30,000 deaths annually in the U.S.,” Yan said.

Results from Deng’s previous research in 2021.

The UofL Hepatobiology and Toxicology Center was created in 2016 with an $11.5 million grant from the NIH to support unique research focused on liver injury and disease and toxicology. The center supports leading-edge research conducted by junior investigators with mentorship from senior researchers, as well as pilot projects and core laboratory facilities that support research across the university. The researchers’ goal is reducing the impact of many types of liver illness through prevention and the development of therapies.

Kentucky leads the nation in increases in cirrhosis-related deaths and in liver cancer-related deaths. According to research published in , mortality due to cirrhosis has been increasing in the U.S. since 2009, with the greatest increase in deaths from cirrhosis in Kentucky. Non-alcoholic fatty liver diseases affect approximately 25% of adults and 10% of children in the U.S.

“This vital research at the University of Louisville advances the health of Kentuckians and people throughout the world,” said UofL President Neeli Bendapudi. “Through this center, UofL researchers will continue to expand their work to find ways to prevent and treat liver illnesses, many of which today have no FDA-approved treatment.”

Researchers at the focus on liver injury, nutrition and gut-liver interactions as well as interactions between the liver and environment, toxicants and drugs. Their ultimate goal is to contribute to the prevention and treatment of non-alcoholic fatty liver disease, non-alcoholic steatohepatitis (a major cause of cirrhosis of the liver), alcoholic liver disease and liver cancer.

“This incredible cohort of researchers is discovering new ways to address the liver illnesses that afflict so many Kentuckians. I am thrilled that young researchers will continue to be supported with COBRE funding at UofL,” said Toni Ganzel, dean of the UofL School of Medicine.

In its first five years, four of the funded junior investigators in the UofL H&T Center received independent NIH research funding, making way for a new cohort of project researchers. The renewal of COBRE funding encourages a continuous supply of researchers in specialized areas of medicine and the search for new disease treatments.

“This unique thematic center is focused on liver injury, disease and toxicology. We evaluate critical barriers in our understanding of the development and progression of liver disease and we define potential therapeutic targets that could transform current practice,” said Craig McClain, associate vice president for health affairs and translational research and principal investigator for the UofL H&T Center. “This new phase will build on that success and extend and strengthen the scope of the program.”  

“To push past the limitations of existing therapeutics, you need COBRE infrastructure grants to establish cutting-edge biomedical research centers and capabilities,” said Joshua L. Hood, a project investigator in the UofL H&T Center. “The more of these capabilities we have, the more we can explore multidisciplinary frontiers in biomedical science to facilitate the development of new treatments for liver-related cancer and other diseases.”

Current projects supported by the center include:

• Yan Li, associate professor in the Department of Surgery, is investigating preventive strategies and possible mechanisms behind non-alcoholic steatohepatitis, a potential precursor of liver cancer.
• Joshua L. Hood, assistant professor in the Department of Pharmacology & Toxicology, is examining how very small membrane-bound compartments known as nanovesicles that are released by cancer cells influence immune function in liver cancer.
• Ming Song, assistant professor in the Department of Medicine, is studying the role of fructose consumption on the disruption of intestinal barrier function in non-alcoholic fatty liver disease.
• Smita Ghare, instructor in the Department of Medicine, is investigating how alcohol-induced changes in the liver contribute to liver inflammation and injury.

UofL has a legacy of liver research dating to the 1970s when faculty members began investigating a cluster of cases of hepatic angiosarcoma, a rare liver cancer caused by exposure to vinyl chloride in a polymer manufacturing facility in an area of West Louisville known as Rubbertown. UofL researchers worked with the community and industry to document and reduce the effects of toxicants on worker health. UofL still maintains a biorepository of blood and liver tissue specimens begun during that research that serves as a resource for investigators studying the effects of environmental exposures on the liver.

In addition to research, the center provides support for community health. During the epidemic of Hepatitis A and C in the last decade, center investigators helped create the Kentucky Hepatitis Academic Mentorship Program. This program helped to train more than 140 primary care providers in the diagnosis and treatment of Hepatitis C. Those diseases now are declining.

Doctoral student Robert Skolik and Associate Professor Michael Menze, in the Department of Biology at the University of Louisville, have found a way to make cell cultures respond more closely to normal cells, allowing drugs to be screened for toxicity earlier in the research timeline.

The vast majority of cells used for biomedical research are derived from cancer tissues stored in biorepositories. They are cheap to maintain, easy to grow and multiply quickly. Specifically, liver cancer cells are desirable for testing the toxicity of drugs for any number of diseases.

“You like to use liver cells because this is the organ that would detoxify whatever drug for whatever treatment you are testing,” Menze said. “When new drugs are being developed for diabetes or another disease, one of the concerns is whether they are toxic to the liver.”

The cells do come with limitations, however. Since they are cancer cells, they may not be as sensitive to toxins as normal cells, so they may not reveal issues with toxicity that can appear much later in the drug testing process.

Skolik and Menze have discovered that by changing two components of the media used to culture the cells, they can make liver cancer cells behave more like normal liver cells. Rather than using standard serum containing glucose, they used serum from which the glucose had been removed using dialysis and added galactose – a different form of sugar – to the media. The tumor cells metabolize galactose at a much slower rate than glucose. This changes the metabolism of the cells making them behave more like normal liver cells.

By using cells cultured with this modified serum, drugs may effectively be screened for toxicity earlier in the research process, possibly saving millions of dollars.

“It started just as a way to sensitize cells to mitochondrial activity, the cellular powerhouse, but then we realized we had a way to investigate how we are shifting cancer metabolism,” Skolik said. “In short, we have found a way to reprogram cancer cells to look – and act – more like normal cells.”

The research is featured on the cover of the April issue of . The cover image was the work of Nilay Chakraborty and Jason Solocinski at the University of Michigan-Dearborn, who developed a new process to obtain live images of the distribution of energy molecules in cells, showing how cells respond to changes in the cell culture conditions.

To fully realize the effect he reported, Skolik also cultured the cells for a longer period of time than usual.

“In the past, people would do a 12-hour adaptation to this new media. But what we showed is if you culture them for 4 to 5 weeks, you have a much more robust shift,” Skolik said. “When it comes to gene expression, you get much more bang for the buck when you adapt them for a longer period.”

Although the modified serum for the cultures requires the additional step of dialysis and longer culture time, it can yield benefits at later testing stages.

“You would reserve this process for key experiments or toxicity screening,” Menze said. “However, if you go into a Phase 1 clinical trial and find toxicity there, it is way more expensive than using this method.”