USF Health preclinical discovery may help identify new therapeutic targets for Alzheimer’s disease, traumatic brain injury and other neurodegenerative diseases

TAMPA, Fla (Nov. 5, 2021) — Neuroinflammatory diseases, including Alzheimer’s disease and traumatic brain injury, have been linked to deposits of a tough protein known as fibrin, derived from the blood clotting factor fibrinogen. These mesh-like fibrin deposits occur outside blood vessels in the brain, contributing to the death of certain central nervous system cells (neurons) that eventually leads to impaired memory.

Now for the first time, a team at the University of South Florida Health (USF Health) Morsani College of Medicine, reported that before soluble fibrinogen is converted into insoluble fibrin molecules that can adversely accumulate, it can connect directly with neurons and cause a damaging inflammatory reaction. The researchers further discovered that fibrinogen specifically binds to two fibrinogen receptors on the surface of neurons: cellular prion protein (PrP^C) and intracellular adhesion molecule-1 (ICAM-1).

USF Health’s David Lominadze, PhD, a professor of surgery and molecular pharmacology and physiology, investigates how microvascular changes induced by neuroinflammation may damage cognition, including short-term memory. | Photo by Allison Long, USF Health Communications.

Their preclinical study was published Sept. 18 in a special issue of MDPI–Biomolecules entitled “Prions and Prion-Like Mechanisms in Disease and Biological Function.”

The findings have implications for identifying targeted therapies to help prevent or stop neurodegeneration in Alzheimer’s disease, traumatic brain injury, or other chronic neuroinflammatory diseases associated with abnormal vascular permeability (leakage) in the brain.

“Fibrinogen is one of the overlooked culprits involved in the processes of neurodegeneration and resulting memory loss,” said principal investigator David Lominadze, PhD, a USF Health professor of surgery, and molecular pharmacology and physiology. “Our study shows that fibrinogen is not only a marker (biological indicator) of inflammation but can be a cause of inflammation in the brain.”

Fibrinogen is a blood plasma protein naturally produced in the liver and travels throughout the bloodstream to other organs and tissues. Outside of blood vessels, fibrinogen is converted by the enzyme thrombin into fibrin during blood clot formation, playing a key role in wound healing.

Dr. Lominadze’s laboratory focuses on understanding molecular changes affecting circulation of blood in the body’s smallest blood vessels — including how microvascular changes induced by inflammation may damage cognition, in particular short-term memory.

Dr. David Lominadze (sitting) with postdoctoral research scholar Nurul Sulimai, PhD (left), and senior biological scientist Jason Brown | Photo by Allison Long, USF Health Communications.

Dr. Lominadze and others have shown that inflammatory disease is associated with a higher concentration of fibrinogen in the blood, increased generation of potentially damaging free radicals, neuronal cell activation and microvascular permeability. In previous studies using their mouse model for mild-to-moderate traumatic brain injury, Dr. Lominadze’s group reported that fibrinogen after crossing the vascular wall accumulated in spaces between the microvessels and astrocytes (another brain cell type connecting vessels and neurons) and activated the astrocytes. This activation coincided with increased neurodegeneration and reduced short-term memory.

In this latest study, the USF Health researchers tested whether fibrinogen, beside interacting with astrocytes, could connect directly with neurons — nerve cells critical for carrying information throughout the human body and coordinating all necessary functions of life.

They treated healthy mouse brain neurons grown in a petri dish with fibrinogen. Fibrinogen increased the death of these neurons, a process that was not influenced by the presence or absence of a thrombin inhibitor preventing the conversion of fibrinogen to fibrin. The finding suggests that soluble fibrinogen and, at later stages, fibrin can have similar toxic effects on neurons.

Furthermore, blocking the function of PrP^C and ICAM-1 fibrinogen receptors on the surface of neurons (essentially stopping fibrinogen from binding tightly to these receptors) reduced inflammatory reactions resulting in neurodegeneration.

“The study revealed that an interaction between fibrinogen and neurons induced an increase in the expression of proinflammatory cytokine interleukin-6, enhanced oxidative damage, and neuronal death, in part due to its direct association (contact) with neuronal PrP^C and ICAM-1,” the study authors wrote.

Interactions of blood plasma protein fibrinogen with its receptors, cellular prion protein (above) and intercellular adhesion molecule (below), on the surface of neurons are shown with red dots using a method called proximity ligation assay.  The presence of red dots indicates interaction of the target protein with its receptor. Neuronal nuclei are shown in blue.  — Microscopic images courtesy of Lominadze Laboratory, USF Health

More research is needed. But altogether the USF Health study suggests that short-term memory problems stemming from neurodegenerative diseases with underlying inflammation may be alleviated by several interventions, Dr. Lominadze said. These include “dampening general inflammation, decreasing fibrinogen concentration in the blood by reducing the synthesis of fibrinogen, and blocking the binding of fibrinogen to its neuron receptors,” he said.

The USF Health research was supported by a grant from the National Heart, Lung and Blood Institute, part of the National Institutes of Health.

Dr. Paul Kuo joins Morsani College of Medicine Sept. 1 

TAMPA, Fla. (Aug. 1, 2017) — The USF Health Morsani College of Medicine has selected Paul C. Kuo, MD, as the new chair of the Department of Surgery.  He will also fill the university’s Richard G. Connar Endowed Chair in Surgery.

Dr. Kuo will join USF Sept. 1 from Loyola University Medical Center in Chicago where he served as the John P. Igini professor and chair of the Department of Surgery since 2010. He was also Loyola’s associate chief medical informatics officer and headed its clinical analytics group known as OnetoMAP, which mines large volumes of data to predict health outcomes. His clinical interests include hepatobiliary surgery, transplantation and minimally invasive surgery.

Paul Kuo, MD

“Dr. Kuo will work with our leadership and hospital partners to continue building a robust Department of Surgery to advance USF Health’s pursuit of academic excellence,” said Charles J. Lockwood, MD, senior vice president for USF Health and dean of the Morsani College of Medicine.  “I am confident that his proven leadership, depth and breadth of expertise, and commitment to value-based care will help us meet this goal.”

During his time at Loyola, Dr. Kuo joined the U.S. Army Reserve Medical Corps where he served in combat operations in Afghanistan treating wounded special operations soldiers.

From 2003 to 2010, Dr. Kuo was chief of the Division of General Surgery and vice chair of research in the Department of Surgery at Duke University Medical Center. He was also a NIH-funded investigator who headed the transplantation surgery team at Duke for eight years.

Before joining Duke, he led the kidney and pancreas transplantation and laparoscopic surgery section of the Division of Transplantation Surgery at Georgetown University Medical Center. He has also held faculty positions at Stanford University Medical Center and the University of Maryland Medical Center.

Dr. Kuo received his M.D. from The Johns Hopkins University School of Medicine, completed an internship and residency in general surgery at Brigham and Women’s Hospital, a fellowship in transplant/hepatobiliary surgery at Beth Israel-Deaconess Hospital and two research fellowships at Harvard Medical School. Dr. Kuo also holds a MBA from the Carey Business School of Johns Hopkins University and a M.S. in medical informatics from Northwestern University.

Dr. Kuo has consistently been named one of the “Best Doctors in America.” He is a fellow of the American College of Surgeons and a member of several surgical and medical societies and associations.

“I look forward to coming to USF Health to help build integrated, multidisciplinary programs that deliver cutting-edge clinical care to patients across the Tampa Bay region and beyond,” Dr. Kuo said.

In addition to leading USF’s surgery department, Dr. Kuo will assume the role of surgeon-in-chief at Tampa General Hospital, and later this year is expected to be named associate chief medical officer for surgical services at the Morsani College of Medicine.

USF Health researcher Mack Wu, MD, studies what happens when the microvascular endothelial barrier controlling blood-tissue exchange is compromised during ischemia-reperfusion injury, a condition that can lead to irreversible tissue damage. He also investigates the molecular control of gut permeability, also known as “leaky gut,” in tissue injuries caused by trauma and severe burns.

His group’s work has broad implications for a variety of conditions including stroke, heart attack, thrombosis, sepsis, trauma or other inflammatory diseases associated with microvascular injury.

Mack Wu, MD, is a professor of surgery and molecular medicine at USF Health Morsani College of Medicine and a research physiologist at James A. Haley Veterans’ Hospital. On the monitor next to him are images of microvessels in the small intestine injected with fluorescent dye.

The closely connected endothelial cells lining the interior of blood vessel walls play a critical role in limiting the how much fluid, proteins and small molecules cross the wall of the tiny blood vessels, or microvessels. However when this protective endothelial barrier is damaged, excessive amounts of blood fluid, proteins and molecules leak outside the microvessels into nearby body tissue – a process known as microvascular hyperpermeability. If this breech of endothelial barrier is associated with a body-wide inflammatory response, it can trigger a chain of events leading to edema (swelling), shock from severe blood and fluid loss (hypovolemic shock), and ultimately multiple organ failure.

Pinpointing potential solutions for ischemia-reperfusion injury

Previous research by Dr. Wu’s laboratory and other groups discovered that ischemia-reperfusion injury can cause endothelial barrier damage leading to vascular hyperpermeability, or abnormally leaky blood vessels.

Ischemia-reperfusion injury is typically associated with conditions like organ transplantation, stroke, heart attack, or cardiopulmonary bypass where blood supply to a vital organ is temporarily cut off (ischemia), resulting in oxygen deprivation. For instance, a period of ischemia occurs while a donor organ is transported to a recipient in the operating room, or when a clot interrupts blood circulation to the brain. When blood supply is re-established with new blood returned to the previously oxygen-deprived area (reperfusion), tissue injury can worsen because the reperfusion itself causes inflammation and oxidative damage rather than restoring normal function. It its severest form, ischemia-reperfusion injury can result in multiple organ failure, or even death.

“I believe endothelial barrier injury is one of the key elements of ischemia-reperfusion injury, so my group is trying to find out which molecule is ultimately responsible for the endothelial barrier damage,” said Dr. Wu, a professor of surgery and molecular medicine at USF Health Morsani College of Medicine and a research physiologist at James A. Haley Veterans’ Hospital.

Dr. Wu with some members of his laboratory team. From left, Rebecca Eitnier, research assistant; Shimin Zhang, Department of Molecular Medicine graduate student; Ricci Haines, research associate; and Fang Wang, research assistant.

With the support of a $1.49-million, four-year R01 grant from the National Heart, Lung and Blood Institute, Dr. Wu’s team is zeroing in on a molecule known as focal adhesion kinase, or FAK, an enzyme that may play a role in weakening the microvascular endothelial barrier during ischemia-reperfusion injury.   Using cell models and a newly developed mouse model in which the endothelial-specific gene for FAK is knocked out, the USF researchers are testing whether selectively inhibiting FAK activity can rescue the endothelial barrier from such injury.

The work is critical because no FDA-approved treatment exists to prevent tissue damage following reperfusion. Identifying a new mechanism for the injury would provide potential targets for drug development, Dr. Wu said. So for instance, he said, after an initial stroke a new intravenously administered drug selectively targeting endothelial cells in the brain’s microvessels might stop further harmful swelling of the brain caused by stroke.

Defining molecular control of “leaky gut” in severe burn trauma

A second grant from the U.S. Department of Veterans Affairs funds Dr. Wu’s studies to define the underlying molecular mechanisms of leaky guts induced by traumatic injury associated with thermal (fire, scald or chemical) burns.  Massive burn trauma is a significant cause of injury and death in American soldiers. With a $960,000 VA Merit Award, Dr. Wu focuses on how intestinal epithelial barrier damage happens during severe burns, with the aim of developing targeted therapies to prevent posttraumatic complications.  In particular, he is working to determine the pathways by which the protein palmitoylation in gut epithelial cells are stimulated by burn injury.

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Epithelial cells line the interior of the small intestines, and after severe burn injury, this protective epithelial barrier commonly breaks down, causing bacteria and toxins to flow from the intestine into the circulating blood.  The result of this abnormal epithelial permeability, or “leaky gut,” can be deadly if sepsis ensues – a bacterial infection in the bloodstream sets up a body-wide inflammatory response leading to multiple organ failure.

While the role gut barrier failure plays in posttraumatic complications is well recognized, its cellular and molecular mechanisms remain poorly understood.  Currently, pushing IV fluids to help prevent hypovolemic shock and administering antibiotics and anti-inflammatories are the only therapies, mostly supportive, Dr. Wu said.

“More effective early therapeutic interventions to prevent leaky gut and systemic inflammatory response will be key to preventing sepsis,” he added, whether in soldiers with trauma or VA patients with inflammatory bowel diseases.

From industry to academia

Dr. Wu joined USF Health and the Haley VA Hospital in 2011.  He came from Sacramento, Calif, where he was an associate professor of surgery at the University of California at Davis School of Medicine and a research physiologist at Sacramento VA Medical Center.   Previously, Dr. Wu was a faculty member in the Department of Medical Physiology at Texas A&M University Health Science Center. He screened pharmaceutical compounds as a toxicologist in a biotechnology laboratory before joining Texas A&M, moving from industry to academia in 1995.

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Dr. Wu received his MD degree from Second Military Hospital in Shanghai, China, and conducted an internship at Shanghai Second Hospital.

One of his earliest and most highly cited studies, published in the American Journal of Physiology (1996), was first to report nitric oxide’s role in contributing to cardiovascular injury. The study showed an increase in nitric oxide induces vascular endothelial growth factor (VEGF) to promote leakage in tiny coronary veins.

Another more recent study in Shock (2012) provided direct evidence that thermal burn injury causes intestinal barrier disruption and inflammation characterized by intestinal mucosal permeability (leakage) and an infiltration of immune system cells known as neutrophils.

Something you may not know about Dr. Wu:

He loves deep-sea fishing. Dr. Wu has fished for sharks off the Golf coast of Texas, rockfish off the Pacific coast of California, and grouper off the west coast of Florida.

Dr. Wu is a member of the USF Health Heart Institute. His team’s work has broad implications for a variety of conditions including stroke, heart attack, thrombosis, sepsis, trauma or other inflammatory diseases associated with microvascular injury.

Photos by Eric Younghans, USF Health Communications and Marketing

University of South Florida-led study helps refine personalized approach to breast cancer diagnosis and treatment

//www.youtube.com/watch?v=N83YjZnz0QE

Tampa, FL (March 6, 2014) – A method called molecular subtyping can help doctors better determine which of their breast cancer patients are at high risk of getting breast cancer again, a new study led by the University of South Florida reports.  This sophisticated genetic profiling of an individual’s specific tumor offers an additional resource to help identify patients who would most benefit from chemotherapy and those who would not.

The findings by researchers from USF and other institutions were presented in a scientific poster at the Miami Breast Cancer Conference, held March 6-9 in Miami Beach, Fla.

“The most important takeaway for our colleagues in breast cancer diagnosis and treatment is the potential value of molecular subtyping to personalize and improve each woman’s treatment,” said principal investigator Charles E. Cox, MD, McCann Foundation Endowed Professor of Breast Surgery, USF Health Morsani College of Medicine.

Dr. Charles Cox led the study looking at sophisticated genetic profiling tests that may help guide breast cancer treatment decisions. The findings were reported in a scientific poster presented at the Miami Breast Cancer Conference 2014.

Molecular subtyping is a way of classifying breast cancer tumors into one of four genetically-distinct categories, or subtypes: Luminal A, Luminal B, Basal (a subset of triple negative), and HER2-type.  Each subtype responds differently to different kinds of treatments, and some subtypes indicate a higher risk of disease recurrence.

“Our data showed that a substantial number of breast cancer patients — classified as low risk by one particular genomic test — turn out to be at high risk of recurrence once we determined their subtype,” Dr. Cox said. “These are mostly Luminal B patients, and their physicians might not fully understand their patient’s situation unless they do subtyping.”

The USF study examined why different genomic tests for breast cancer sometimes provide contradictory information about risk of recurrence. The key findings involved the 70-gene MammaPrint® test; the 21-gene Oncotype DX® test, which is an earlier commercially available test; and Mammostrat®, a gene profiling test performed on slides of the breast tumor by a pathologist. The tests have generally been assumed to provide equivalent information about recurrence risk, but that is proving not to be the case.

Researchers examined tumor samples from a total of 148 patients. The greatest discordance (lack of agreement) about risk of disease recurrence occurred in a group of 51 patients.  Of those 51, all were stratified by MammaPrint as high risk of recurrence, while Oncotype classified 18 of them (35 percent) as low risk.

BluePrint®, an 80-gene test to identify a tumor’s molecular subtype, was also used for those stratified by MammaPrint. This process revealed that the 51 patients were Luminal B, a molecular subtype with a high risk of recurrence.

Steve Shivers, PhD, a research scientist in the USF Health Department of Surgery, was a study co-author.

Patients with a high risk of recurrence are normally counseled to receive chemotherapy following surgery to prevent the cancer from returning.  In contrast, women whose subtype has a low risk of recurrence (Luminal A) will not benefit from the addition of chemotherapy. They may thus be able to safely avoid chemotherapy and its potentially damaging side effects.  At the same time, they can be prescribed treatments such as hormonal therapy known to benefit those with their subtype.

The additional information provided by genomic tests and molecular subtyping may help reduce overall treatment costs for breast cancer, by targeting chemotherapy only for those women who will benefit from it,  Dr. Cox said  “Personalized treatment guided by these tests may also extend the time that patients are free of their cancer.”

Registered nurse George Ann Vincent, a Tampa, Fla. resident and a patient of Dr. Cox, was diagnosed with early-stage breast cancer last year. The 70-gene test determined that her tumor had a high risk of recurrence, so she was prescribed chemotherapy.

“I’m certainly grateful that I’m getting the treatments that are right for me,” Vincent said. “Chemotherapy is no picnic, but it can save lives. The genomic tests I took made me confident I was being sent in absolutely the right direction.”

Dr. Cox clarified that discordance does not necessarily show that some genomic test results were wrong.

“These tests use different genes and were validated on different types of populations,” he said. “But if physicians use molecular subtyping as we did in this study, they will have valuable, additional information to guide the appropriate treatment for each patient.”

Using molecular subtyping in combination with traditional biomarkers, like tumor grade and hormone receptor status, for determining the biological nature of a woman’s cancer is a recommended guideline for breast cancer treatment in both the United States and Europe, Dr. Cox said.

Other poster co-authors included researchers from Florida Hospital Tampa; Morton Plant Hospital, Clearwater, Fla.; and Agendia NV, a molecular diagnostics firm.

-USF Health-

USF Health’s mission is to envision and implement the future of health. It is the partnership of the USF Health Morsani College of Medicine, the College of Nursing, the College of Public Health, the College of Pharmacy, the School of Biomedical Sciences and the School of Physical Therapy and Rehabilitation Sciences; and the USF Physician’s Group. The University of South Florida is a global research university ranked 50^th in the nation by the National Science Foundation for both federal and total research expenditures among all U.S. universities.

Media contact:
Anne DeLotto Baier, USF Health Communications
abaier@health.usf.edu or (813) 974-3303