USF Health researchers applied CRISPR technology to study the very large human non-protein coding gene expressed only in placenta, stem cells and certain cancers

TAMPA, Fla (March 16, 2020) — The placenta, an organ which attaches to the lining of the uterus during pregnancy, supplies maternal oxygen and nutrients to the growing fetus. Abnormal formation and growth of the placenta is considered an underlying cause of various pregnancy complications such as miscarriages, stillbirth, preeclampsia and fetal growth restriction. Yet, much remains to be learned about molecular mechanisms regulating development of this blood-vessel rich organ so vital to the health of a pregnant woman and her developing fetus.

Hana Totary-Jain, PhD, an associate professor of molecular pharmacology and physiology in the USF Health Morsani College of Medicine, was senior author of the study published in Scientific Reports.

University of South Florida Health (USF Health) Morsani College of Medicine researchers recently discovered how a very large human non-protein coding gene regulates epithelial-to-mesenchymal transition (EMT) – a process that contributes to placental development during early pregnancy, but can also promote cancer progression.

During the first trimester, fetal-derived placental cells known as trophoblasts invade the maternal uterine lining and modify its blood vessels to allow oxygenated blood to flow from the mother to fetus. However, trophoblast invasion requires tight regulation of EMT. If inadequate, trophoblast invasion is too shallow to adequately remodel the maternal blood vessels, and adverse pregnancy outcomes can occur. Conversely, excess EMT can cause exaggerated trophoblast invasion through the uterine wall leading to placenta accreta, a condition that can cause hemorrhage and often requires hysterectomy at delivery.

The USF Health researchers used a powerful genome editing technology called CRISPR (shorthand for “CRISPR-dCas9) to activate all of the chromosome 19 microRNA cluster (known as C19MC), so they could study the gene’s function in early pregnancy. C19MC — one of the largest microRNA gene clusters in the human genome — is normally turned off but becomes expressed only in the placenta, embryonic stem cells and certain cancers.

Dr. Totary-Jain discusses the molecular aspects of placenta development and pregnancy complications with research collaborator Umit Kayisli, PhD, a professor of obstetrics and gynecology at USF Health.

In their cell model study, published Feb. 20 in Scientific Reports, a Nature research journal, the USF Health team showed that robust activation of C19MC inhibited EMT gene expression, which has been shown to reduce trophoblast invasion.

But when trophoblast-like cells were exposed to hypoxia – a lack of oxygen similar to that occurring in early placental development — C19MC expression was significantly reduced, the researchers found. The loss of C19MC function causes differentiation of trophoblasts from stem-like epithelial cells into mesenchymal-like cells that can migrate and invade much like metastatic tumors. This EMT process helps explain trophoblast invasion and early placental formation.

“We were the first to use CRISPR to efficiently activate the entire gene, not just a few regions of this huge gene, in human cell lines,” said the paper’s senior author Hana Totary-Jain, PhD, an associate professor in the Department of Molecular Pharmacology and Physiology, USF Health Morsani College of Medicine. “Our study indicates C19MC plays a key role in regulating many genes important in early implantation and placental development and function. The regulation of these genes is critical for proper fetal growth.”

Above: Chromosome 19 microRNA cluster (stained purple) expressed in first-trimester placenta.  Below: In preparation for pregnancy, fetal trophoblast cells (brown) from which the placenta arises invade maternal decidual cells (pink) in the uterus lining. | Images courtesy of Hana Totary-Jain, originally published in Scientific Reports: doi.org/10.1038/s41598-020-59812-8

“You need EMT, but at some point the process needs to cease to prevent adverse pregnancy outcomes,” Dr. Totary-Jain said. “You really need a balance between not enough invasion and too much invasion, and C19MC is important in maintaining that balance.”

Dr. Totary-Jain and others in her department collaborated with colleagues in the medical college’s Department of Obstetrics and Gynecology on the project.

“The USF Health study offers new insight into how trophoblasts interact with the maternal uterine environment to become more invasive or less invasive in the formation of the placenta,” said coauthor Umit Kayisli, PhD, a USF Health professor of Obstetrics and Gynecology. “More research on microRNA expression and how it inhibits EMT may help us better understand the causes and potential prevention of preeclampsia and fetal growth restriction, which account for 5-to-10 percent of all pregnancy complications as well as spontaneous preterm births.”

Investigating the effects of altered C19MC expression on cell differentiation and trophoblast invasion has implications not only for a better understanding of normal and abnormal placental development, but also for cancer and stem cell research, Dr. Totary-Jain added.

Dr. Totary-Jain and Dr. Kayisli

Photos by Freddie Coleman, USF Health Communications and Marketing

University of South Florida study suggests a new approach to inhibit the buildup of brain-damaging tau tangles associated with FTLD, Alzheimer’s disease and related dementias

TAMPA, Fla. (Feb. 18, 2020) — The protein β-arrestin2 increases the accumulation of neurotoxic tau tangles, a cause of several forms of dementia, by interfering with removal of excess tau from the brain, a new study by the University of South Florida Health (USF Health) Morsani College of Medicine found.

A beta-arrestin2 oligomer (foreground) shown within a nerve cell (background). Oligomerized beta-arrestin2 plays a central role in impairing tau clearance and the development of tau aggregates (magenta) in frontotemporal lobe degeneration and Alzheimer’s disease. | Image courtesy of artist Cynthia Greco and Eric Lewandowski (beta-arrestin2 protein modeling)

The USF Health researchers discovered that a form of the protein comprised of multiple β-arrestin2 molecules, known as oligomerized β-arrestin2, disrupts the protective clearance process normally ridding cells of malformed proteins like disease-causing tau. Monomeric β-arrestin2, the protein’s single-molecule form, does not impair this cellular toxic waste disposal process known as autophagy.

Their findings were first published Feb. 18 in the Proceedings of the National Academy of Science (PNAS).

The study focused on frontotemporal lobar degeneration (FTLD), also called frontotemporal dementia — second only to Alzheimer’s disease as the leading cause of dementia. This aggressive, typically earlier onset dementia (ages 45-65) is characterized by atrophy of the front or side regions of the brain, or both. Like Alzheimer’s disease, FTLD displays an accumulation of tau, and has no specific treatment or cure.

“Our research could lead to a new strategy to block tau pathology in FTLD, Alzheimer’s disease and other related dementias, which ultimately destroys cognitive abilities such as reasoning, behavior, language, and memory,” said the paper’s lead author JungA (Alexa) Woo, PhD, an assistant professor of molecular pharmacology and physiology and an investigator at the USF Health Byrd Alzheimer’s Center.

“It has always been puzzling why the brain cannot clear accumulating tau” said Stephen B. Liggett, MD, senior author and professor of medicine and medical engineering at the USF Health Morsani College of Medicine. “It appears that an ‘incidental interaction’ between β-arrestin2 and the tau clearance mechanism occurs, leading to these dementias. β-arrestin2 itself is not harmful, but this unanticipated interplay appears to be the basis for this mystery.”

The USF Health research team included, from left: Stephen Liggett, MD, senior author; David Kang, PhD, coauthor; and JungA (Alexa) Woo, PhD, lead author. | Photo by Freddie Coleman

“This study identifies beta-arrestin2 as a key culprit in the progressive accumulation of tau in brains of dementia patients,” said coauthor David Kang, PhD, professor of molecular medicine and director of basic research for the Byrd Alzheimer’s Center. “It also clearly illustrates an innovative proof-of-concept strategy to therapeutically reduce pathological tau by specifically targeting beta-arrestin oligomerization.”

The two primary hallmarks of Alzheimer’s disease are clumps of sticky amyloid-beta (Aβ) protein fragments known as amyloid plaques and neuron-choking tangles of a protein called tau. Abnormal accumulations of both proteins are needed to drive the death of brain cells, or neurons, in Alzheimer’s, although the tau accumulations now appear to correlate better with cognitive dysfunction than Aβ, and drugs targeting Ab have been disappointing as a treatment. Aβ aggregation is absent in the FTLD brain, where the key feature of neurodegeneration appears to be excessive tau accumulation, known as tauopathy. The resulting neurofibrillary tangles — twisted fibers laden with tau — destroy synaptic communication between neurons, eventually killing the brain cells.

“Studying FTLD gave us that window to study a key feature of both types of dementias, without the confusion of any Aβ component,” Dr. Woo said.

Monomeric β-arrestin2 is mostly known for its ability to regulate receptors, molecules on the cell that are responsible for hormone and neurotransmitter signaling. β-arrestin2 can also form multiple interconnecting units, called oligomers. The function of β-arrestin2 oligomers is not well understood.

The monomeric form was the basis for the laboratory’s initial studies examining tau and its relationship with neurotransmission and receptors, “but we soon became transfixed on these oligomers of β-arrestin2,” Dr Woo said.

Neurofibrillary tangles laden with tau (stained red) destroy synaptic communication between neurons, eventually killing the brain cells. This tau pathology is a feature of frontotemporal dementia, Alzheimer’s disease and several other dementias. | Image courtesy of David Kang

Among the researchers’ findings reported in PNAS:

– Both in cells and in mice with elevated tau, β-arrestin2 levels are increased. Furthermore, when β-arrestin 2 is overexpressed, tau levels increase, suggesting a maladaptive feedback cycle that exacerbates disease-causing tau.

–  Genetically reducing β-arrestin2 lessens tauopathy, synaptic dysfunction, and the loss of nerve cells and their connections in the brain. For this experiment researchers crossed a mouse model of early tauopathy with genetically modified mice in which the β–arrestin2 gene was inactivated, or knocked out.

– Oligomerized β-arrestin2 — but not the protein’s monomeric form – increases tau.  The researchers blocked β-arrestin-2 molecules from binding together to create oligeromized forms of the protein. They demonstrated that pathogenic tau significantly decreased when β-arrestin2 oligomers are converted to monomers

– Oligomerized β-arrestin2 increases tau by impeding the ability of cargo protein p62 to help selectively degrade excess tau in the brain. In essence, this reduces the efficiency of the autophagy process needed to clear toxic tau, so tau “clogs up” the neurons.

– Blocking of β-arrestin2 oligomerization suppresses disease-causing tau in a mouse model that develops human tauopathy with signs of dementia.

Above: Control nerve cells (green), in which oligomerized beta-arrestin-2 contributes to the accumulation of disease-causing tau (magenta). Below: When the neurons are transduced with b-arrestin2 oligomerization blocking viruses, tau pathology is dramatically reduced. | Images appearing in PNAS (Fig 6D) courtesy of Alexa Woo

“We also noted that decreasing β-arrestin2 by gene therapy had no apparent side effects, but such a reduction was enough to open the tau clearance mechanism to full throttle, erasing the tau tangles like an eraser,” Dr. Liggett said. “This is something the field has been looking for — an intervention that does no harm and reverses the disease.”

“Based on our findings, the effects of inhibiting β-arrestin2 oligomerization would be expected to not only inhibit the development of new tau tangles, but also to clear existing tau accumulations due to the mechanism of enhancing tau clearance,” the paper’s authors conclude.

The work is consistent with a new treatment strategy that could be preventive for those at risk or with mild cognitive impairment, and also for those with overt dementias caused by tau, by decreasing the existing tau tangles.

The study was supported in part by grants from the National Institutes of Health, National Institute on Aging.

Studies led by USF’s Dr. Stephen Liggett shed light on genetic variability of adrenergic receptors and how they might best be used to treat disease

Dr. Stephen Liggett, who leads the research enterprise for the Morasani College of Medicine and for USF Health, also oversees a genomics laboratory working on NIH-funded studies. Behind him is a radioligand binding machine used to determine the number of receptors in each cell.

While significant progress has been made managing asthma over the last two decades, about half of all asthmatics achieve optimal control of this chronic inflammatory disease using currently available medications.  Similarly, only about 50 percent of patients with congestive heart failure, which occurs when the heart is too weak to pump enough blood to meet the body’s needs, have an average life expectancy of more than five years.

More still needs to be  known at the molecular level about these common diseases to identify potential new targets for drug therapies, said Stephen B. Liggett, MD, associate vice president for research at USF Health, vice dean for research at the Morsani College of Medicine, and professor of internal medicine and molecular pharmacology and physiology.

What ties these two diseases together are the receptors on cardiac muscle and on smooth muscle of the airways. Dr. Liggett’s laboratory helps shed light on the genetic variability of adrenergic receptors and on how these receptors can best be used for treatment. The genetic studies have been particularly useful in developing the concept of pharmacogenetics, a tailoring of therapy based on an individual’s genetic makeup, for heart failure and asthma.

“Twenty years ago we had a handful of medicines for high blood pressure, and today we don’t use any of them. Now, we have a whole new group of more effective (antihypertensive) drugs with much fewer side effects,” he said.  “And, I’m sure that one day, we’ll have more tools in our toolbox to better treat heart failure and asthma – drugs that work better for subgroups of people as defined by their genetic makeup and environmental exposures.”

 Dr. Liggett comments on some of his laboratory’s contributions to the field over his career.

The research team led by Dr. Liggett, center, includes Ashley Goss, Hiwot Zewdie, Donghwa Kim, PhD, and Maria Castano. Not pictured: Alexa Woo, PhD.

Mining a “superfamily” of receptors for better drug targets

Dr. Liggett leads a USF team that studies the genetic, molecular biology, structure and function of G-coupled protein receptors, or GPCRs, the largest family of human proteins.  More than 800 GPCRs have been discovered within cell membranes in the human body, Dr. Liggett said, and one or more of these receptors plays a role in virtually everything the body does, including controlling thoughts in the brain, sight and smell, uterine contraction and relaxation, blood pressure, cardiac, lung and kidney function, to name just a few.

Consequently, malfunctions of GPCR signaling pathways are implicated in many chronic diseases including asthma and cardiovascular diseases.  Already this “superfamily” of receptors accounts for nearly half the targets of all prescribed drugs. But, a deeper understanding of the dynamics of the GPCR signaling network and how it maintains a healthy cell or responds to pathogens could lead to the design of drugs that more precisely target diseases with greater effectiveness and fewer side effects.

Dr. Liggett began his work with GPCRs in 1988 as a Howard Hughes Institute postdoctoral research fellow in the Duke University Medical Center laboratory of mentor Robert Lefkowitz, MD. Dr. Lefkowitz was awarded the 2012 Nobel Prize in Chemistry with Brian Kobilka, MD, for groundbreaking discoveries revealing the inner workings of GPCRs.

Building upon his interest and advanced training in pulmonary and critical care medicine, Dr. Liggett began early in his career to concentrate on one of the classes of GPCRs known as adrenergic receptors, which are stimulated by the hormone epinephrine and the neurotransmitter norepinephrine. They are involved in increasing the rate and force of contraction of the heart, as well as constriction and dilation of blood vessels throughout the body and of airways in the lung. For the last 28 years, he has been continuously funded by the National Institutes of Health (NIH) to study the molecular basis of beta-adrenergic receptors in asthma.

Biological scientist Ashley Goss

Dr. Liggett is the principal investigator of a four-year, $1.12-million R01 grant from the NIH’s National Heart, Blood and Lung Institute (NHBLI) that seeks to understand how beta-adrenergic signaling is regulated to influence the development and treatment of asthma. Over his career, he has also been awarded millions of dollars in NIH funding to explore the role of genetic variations of GPCRs in heart failure, including whether those variations may alter how effectively drugs work in individual patients.

Bitter taste receptors in a new place

Dr. Liggett is also currently a project principal investigator for a five-year, $2-million NHBLI P01 grant examining how airway smooth muscle bitter taste receptors might be applied as new treatments for asthma and chronic obstructive pulmonary disease.

Using a genomics-based method that Dr. Liggett pioneered, his team had previously identified bitter taste receptors, initially thought only to exist on the tongue, deep inside the lung at the airway smooth muscle and demonstrated they act to open the airway. “When activated, they appear far superior to the beta-agonists commonly prescribed to patients to open their airways during an asthma attack,” said Dr. Liggett, who published the discovery and the need for alternatives to current bronchodilators in Nature Medicine and other journals.

Overall, discoveries emerging from Dr. Liggett’s research have yielded more than 250 peer-reviewed papers, many highly cited and appearing in top journals such as Nature Medicine, Science, Proceedings of the National Academy of Sciences, and the New England Journal of Medicine. His work has been cited by other papers more than 26,000 times. He also holds 18 patents detailing potential new targets for drug therapy or genetic variations of known drug targets and how they might be used to predict response to medications and customize treatment.

 The serendipity of finding bitter taste receptors on smooth airway muscle in the lungs

Laboratory assistant Hiwot Zewdie

Among some of his laboratory’s major findings:

– While at the University of Maryland, Dr. Liggett’s team worked with colleagues at the University of Wisconsin-Madison to sequence for the first time the entire genomes (more than 100 different strains) of all known rhinoviruses, a frequent cause of respiratory infections including the common cold. The groundbreaking work, published on the cover of Science, provided a powerful framework for large-scale, genome-based epidemiological studies and the design of antiviral agents or vaccines to combat rhinoviruses. “I originally suggested sequencing 10 strains, and then my collaborator asked why not do them all,” he said. “This made the difference between a mediocre proof-of-concept paper and a full article in Science. I learned that it is important to think big if you want to make a real difference”

–  Discovered and characterized genetic variations that may predict which patients with congestive heart failure respond best to a life-saving beta-blocker drug.  These landmark studies occurred over several years and were published in Nature Medicine twice, and the Proceedings of the National Academy of Sciences three times. “This is a good example of the progression of an idea over time, where every year or so an unexpected turn of events occurred, and new insight was gained,” he said.

– While at the University of Cincinnati, Dr. Liggett, working with colleagues at Washington University and Thomas Jefferson University, found that a genetic variation of an enzyme, which inhibits beta-adrenergic receptor signaling, confers “genetic beta-blockade” in cardiac muscle and protects against early death in African Americans with heart failure.  The findings, published in Nature Medicine, provided insight into individual variations in disease outcomes. Another key study from Cincinnati revealed that a certain combination of genetic variants within a single gene conferred low vs. excellent responses to inhaled beta-agonists in treating asthma. These combinations, called haplotypes, had never been identified in GPCRs. The work was published in Proceedings of the National Academy of Sciences.

Dr. Liggett’s groundbreaking research sequencing all known human rhinoviruses, a frequent cause of respiratory infections, was featured on the April 3, 2009 cover of the journal Science.

Advancing outside his field of study

Dr. Liggett joined USF Health in 2012 from the University of Maryland School of Medicine in Baltimore, where he was associate dean for interdisciplinary research and professor of medicine and physiology. He received his MD degree at the University of Miami and completed both a residency in internal medicine and fellowship in pulmonary diseases and critical care medicine at Washington University School of Medicine and Barnes Hospital in St. Louis, MO.

Within two years, he advanced from a postdoctoral research fellowship in Dr. Lefkowitz’s laboratory at Duke to tenured associate professor and director of pulmonary and critical care medicine at the University of Cincinnati College of Medicine.  By the time he left Cincinnati for the University of Maryland in 2005, he held an endowed chair in medicine and directed the university’s Cardiopulmonary Research Center.

Though he had no significant wet-lab experience, Dr. Liggett was fascinated by the emerging science called “molecular biology” and was undeterred from branching into a field of study in which he had no formal training.

He secured a position as assistant professor at Duke following his fellowship there, and figured out how to sequence adrenergic receptor genes from a patient’s blood. While routine now, such genetic testing had not been done previously.  He unexpectedly kept finding multiple variations (called polymorphisms or mutations) in genes coding for the same receptors, so he sought out the advice of some classic geneticists.  At the time, Dr. Liggett said, their traditional thought was modeled after diseases like cystic fibrosis — if a person had the genetic mutation they developed the disease, if the mutation was absent they did not.

“There was no consideration for common genetic variants and how they might affect disease risk, progression, or response to treatment. It simply was not in their thought process,” Dr. Liggett said. He was told “it’s probably nothing and don’t quit your day job.” He did not take their advice.

 Some advice Dr. Liggett would give to emerging young scientists

Assistant professor Donghwa Kim, PhD

Instead, he returned to the laboratory to sequence and clone receptors from many different populations with asthma and heart failure, showing that the receptor genes did indeed differ from one individual to another, generally with several common “versions.” His team also created “humanized” mice expressing the human genes for asthma and heart failure so they could begin to understand the physiology of the receptors. They began to find that some genetic alterations increased receptor function, some decreased the drug’s affinity to bind (responsiveness) to a receptor, and still others altered how the receptor was regulated.  And, through NIH-supported clinical trials, the researchers correlated outcomes observed in patients undergoing drug therapies with the genetic variations uncovered in the laboratory.

“If there’s a lesson to be learned here by young investigators, I’d say it’s that you can collect information from experts in the field, but you need to use your gut to ultimately decide on whether to pursue a line of research or not,” Dr. Liggett said.

Personalized medicine challenge: Common diseases, multiple genetic variations

Realizing personalized medicine’s full potential will require a better understanding of how environmental variables – including diet, exercise, the gastrointestinal microbiome (gut bacteria) and toxin exposure – combine with genetic variations to affect disease and its treatment, he said. “Personalized medicine faces its greatest challenges in the common diseases like asthma, atherosclerotic heart disease and heart failure, because they involve multiple variations in multiple genes that interact with the environment to give you a disease – and also provide a set-up for unique ways to treat the disease.”

Biological scientist Maria Castano

Dr. Liggett was one of the first physicians recruited for what would become the USF Health Heart Institute.  He recalls that he still had the letter of offer in his pocket when he stood before the Hillsborough County Commission in 2012 to help USF Health leadership pitch the need for a cardiovascular institute to include a focus on genomics-based personalized medicine.  The county joined the state in funding the project, and Dr. Liggett was instrumental in the early planning stages of the Heart Institute before the arrival of its founding director Dr. Samuel Wickline.  The institute is now under construction in downtown Tampa as part of the new Morsani College of Medicine facility, a key anchor of Water Street Tampa. Already, 21 of the 31 institute’s biomedical scientists who will investigate the root causes of heart and vascular diseases with the aim of finding new ways to detect, treat and prevent them, have been recruited.

“There’s an excitement here and philosophy of excellence that’s rewarding to see,” Dr. Liggett said. “We have a strategic plan in place, including moving ahead to expand research in cardiovascular disease, infectious disease and the microbiome, and the neurosciences. Our departments are recruiting at a good pace, and the faculty we’re bringing in all have NIH funding and are highly collaborative.”

Dr. Liggett is an elected fellow of the American Association for the Advancement of Science – one of only five Morsani College of Medicine faculty members to receive that prestigious honor.  He is also an elected Fellow of the National Academy of Inventors and the American College of Chest Physicians. Last year, he was one of 30 scientists nationwide selected to join The Research Exemplar Project – recognition of his outstanding reputation as a leader whose high-impact, federally-funded research yields novel and reproducible results.

Over his career, he has served on several NIH study sections and on the editorial board of high-impact journals relevant to fundamental biochemistry as well as heart and lung diseases.  He is currently editor-in-chief of the Journal of Personalized Medicine.

 The potential of new treatments for asthma and heart failure

Dr. Liggett holds 18 patents detailing potential new targets for drug therapy or genetic variations of known drug targets, which might be used to predict response to medications and customize treatment.

Some things you may not know about Dr. Liggett:

• He has asthma, which helps motivate his research toward finding better treatments for this common lung disease affecting one in 12 people in the United States.
• Restores vintage cars, primarily DeLoreans. Although he recently finished bringing a funky lime green 1974 Volkswagen Thing back to life, and over the holidays restored a 1973 VW camper. 

• Lives with wife Julie on the beach in Treasure Island, where they enjoy surfing, paddle boarding, and photography.
• Has three children – Elliott, an engineer at NASA’s Jet Propulsion Laboratory at Cal Tech in Pasadena, CA; Grace, who recently completed her master’s degree in public health at USF; and Mara, an undergraduate student studying social work at Florida Atlantic University, and two step-children — Madison, an undergraduate at the University of Florida, and Tripp, a senior at St. Petersburg Catholic High School. He also has three grandchildren, ages 2 to 9.

Photos by Sandra C. Roa, and audio clips by Eric Younghans, University Communications and Marketing

Jerome Breslin studies what happens when the endothelial barrier is breeched by traumatic injury and inflammation

Traumatic injury is the leading cause of death among people ages 1 to 44 in the United States. The body’s inflammatory response accompanying massive injury can severely complicate the resuscitation of trauma victims, worsen clinical outcomes and often lead to multiple organ failure.

In his laboratory at the USF Health Morsani College of Medicine, Jerome Breslin, PhD, and colleagues study microvascular hyperpermeability, that is, the “excessively leaky” small blood vessels that are a hallmark of systemic inflammation.  Their aim is to find new, more effective ways to treat trauma and prevent early death, but their work also has implications for the treatment of lymphedema, wound healing and arteriosclerosis.

Jerome Breslin, PhD, can do live imaging of vascular endothelial cells under a microscope that he helped build.

In particular, Dr. Breslin, an associate professor in the Department of Molecular Pharmacology and Physiology, looks at what happens when the protective barrier of endothelial cells forming an interface between circulating blood and tissues outside the blood vessel network is compromised by traumatic injury and inflammation.

Leaky blood vessels: The soaker hose analogy

“These capillaries are like soaker hoses used to water plants, that leak out fluid carrying proteins and other nutrients in addition to delivering oxygen to surrounding tissue,” Dr. Breslin said. “In patients who have undergone trauma or major surgery, blood pressure drops in part because the wall of the hose becomes too leaky. There is less fluid in the blood vessels and more flowing out into nearby tissues, which can cause damage and impair the function of some organs.”

In addition to investigating ways to prevent excessive blood vessel leakage, Dr. Breslin’s lab focuses on how to return the leaked fluid back into the blood by the lymphatic vessels.  As a result, his team spends a lot of time studying the pumping function of the lymphatic system, which manages fluid levels in the body. Swelling, or edema, occurs when it fails to drain off excess fluid.

Dr. Breslin’s work is currently supported by two National Institutes of Health RO1 grants totaling more than $2 million.

Dr. Breslin with two undergraduate students who conduct research in his laboratory: Andrea Burgess (American Physiological Society IOSP Summer Fellow) and Sara Spampinato, center (NIH Diversity Grant recipient).

 Dr. Breslin comments on his approach to research problems.

The most recent award from the NIH’s National Institute of General Medical Sciences focuses on testing whether a class of drugs that activate the S1P1 receptor may keep blood vessels from leaking too much and stabilize blood pressure following trauma.

In this project, Dr. Breslin will use the first rat model combining alcohol intoxication and hemorrhagic shock to induce excessive leakiness in small blood vessels. He will evaluate whether fluid containing sphingosine-1-phosphate (S1P) reduces the blood vessel permeability, thereby restoring normal blood pressure and fluid balance. If so, Dr. Breslin said, drugs similar to S1P, a bioactive lipid that prevents cell death, may offer a more effective way for paramedics and physicians to resuscitate trauma patients than the standard IV fluid therapy now administered.  That standard fluid resuscitation protocol works particularly poorly in alcohol-intoxicated victims suffering major blood loss, a significant portion of all trauma cases coming through emergency rooms, he said.

With the second award, a competitive renewal from the NIH’s National Heart, Blood and Lung Institute, Dr. Breslin and colleagues are studying the molecular and cellular mechanisms that may regulate and resolve microvascular leakage following inflammation caused by traumatic injury.

Dr. Breslin points to a human heart valve suspended in a test tube solution. His group plans to study the microvessels within heart valves.

Unexpected finding leads to “new way of thinking”

Previous work by his group using live imaging of vascular endothelial cells under a microscope demonstrated that when the edges of these cells make contact with their neighboring cells they appear very active and are constantly remodeling, or changing shape — rapidly opening up holes at cell junctions and then closing back up. This finding, published in the journal PLOS One, countered one of the conventional theories that endothelial cells were more rigid at the junctions where they connect and adopted a contracted state during inflammation.

“It was an unexpected finding that changed our thinking about how these cells behaved,” Dr. Breslin said.

This led the researchers to begin to question the prevailing view about the role actin stress fibers — threadlike structures involved in cell stability, adhesion and movement — play in disrupting the endothelial barrier function.

Further preclinical studies by Dr. Breslin and others over several years showed that in response to an inflammatory agent actin stress fibers cause endothelial cells to spread out, not contract, at the junctions. The USF researchers published evidence in the American Journal of Physiology: Cell Physiology that actin stress fiber formation may be a reaction to, rather than a cause of, reduced integrity of the endothelial barrier that protects against excessive fluid leakage.

Earlier this year, Dr. Breslin was first author on a study appearing in the Journal of the American Heart Association showing that the signaling protein Rnd3 reduced leakage of small blood vessels when delivered a new way in a rat model of hemorrhagic shock. The researchers suggested Rnd3 (or analog drugs) might offer an anti-inflammatory treatment to repair the endothelial barrier compromised by prolonged and uncontrolled inflammation.

  Dr. Breslin talks about his most exciting experiment

//www.youtube.com/watch?v=lm2ag8m1QqQ

Live imaging of endothelial microvascular cells at 600x magnification shows the dynamic movement of the protruding cell edges (local lamellipodia). Videoclip courtesy of Jerome Breslin, PhD. 

Heart Institute, former mentor a draw to USF

Dr. Breslin joined USF in 2012 from Louisiana State University Health Sciences Center in New Orleans, where he was an assistant professor of physiology.  He received his PhD in pharmacology and physiology from Rutgers University – New Jersey Medical School in Newark, NJ.  His postdoctoral training was conducted at both Texas A&M and the School of Medicine at the University of California Davis, where he was mentored by Sarah Yuan, MD, PhD, the chair of Molecular Pharmacology at Physiology at Morsani College of Medicine who is nationally recognized for her translational research on the regulation of microcirculation.

The opportunity to be part of a growing university, join core faculty who will help build a Heart Institute advancing bench-to-bedside cardiovascular research, and work again with Dr. Yuan attracted him to USF Health, Dr. Breslin said.

“Dr. Yuan was a great mentor to me when I was a postdoctoral fellow,” he said. “This has reopened our scientific collaborations and now we’re mentoring a student together.”

Dr. Breslin, center, with some members of his laboratory.

  His advice to emerging scientists

Dr. Breslin is a fellow of the American Physiological Society Cardiovascular Section and a member of The Microcirculatory Society and the American Heart Association.  He is associate editor of the journal Microcirculation and a member of the editorial board of PLOS One.  He has authored or co-authored nearly 40 articles in peer-reviewed journals.

Dr. Breslin serves on two NIH special emphasis panels, one on lymphatics and another for the Intramural Postdoctoral Research Associate Program.  He is also a grant reviewer for the Association of American Medical Colleges (AAMC) Innovations in Research and Research Education Awards.

Something you may not know about Dr. Breslin

To help pay for tuition while earning his master’s degree in biology, Dr. Breslin worked as a park ranger in Somerset County, N.J, for a couple of summers.

No stranger to outdoor activities, including camping, as a teen Dr. Breslin attained the rank of Eagle Scout, the highest achievement in the Boy Scouting program.  His connection with scouting continues today as committee chair for his 13-year-old son’s Boy Scout troop.

Dr. Breslin’s Scouting experiences included learning wilderness survival skills, such as how to build a shelter from scratch in the woods or navigating a group of boys through the wilderness without a map and compass, or a smartphone for that matter. They were instrumental, he said, in helping him develop the resourcefulness and leadership skills he hopes to impart to the emerging scientists he mentors in his laboratory

In case you’re wondering, one of the most challenging of the merit badges he earned as a Boy Scout: bugling.

Photos and audioclips by Sandra C. Roa, USF Health Communications and Marketing

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At the University of South Florida’s Hyperbaric Biomedical Research Laboratory, ongoing work to combat oxygen toxicity seizures in Navy divers has expanded to include research that may lead to non-toxic cancer therapies combining dietary supplements and hyperbaric oxygen.

Jay Dean, PhD, professor in the Department of Molecular Pharmacology and Physiology, USF Health Morsani College of Medicine, created and has directed the collaborative research facility since it opened in 2006.  The laboratory houses chambers that can mimic the adverse environments of high atmospheric pressure (hyperbaric) experienced by deep-sea divers. With instrumentation specially designed to operate under extreme pressures, Dr. Dean and his colleagues can analyze the molecular responses of cells as well as the physiological changes in animal models exposed to changing concentrations of oxygen, nitrogen and other gases.

Jay Dean, PhD, professor of molecular pharmacology and physiology, established and directs the USF Hyperbaric Biomedical Research Laboratory.

To date, Dr. Dean and his USF colleague, Dominic D’Agostino, PhD, have adapted electrophysiology, radio-telemetry and various types of microscopy techniques for use under hyperbaric pressures, including fluorescence, confocal and atomic force microscopy.

“Atomic force microscopes are common, but not atomic force microscopes placed under hyperbaric pressure,” said Dr. Dean, one of the world’s leading experts in hyperbaric neurophysiology. “We’ve been able to successfully apply very powerful research tools to these unique conditions.” 

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Probing oxygen toxicity’s role in seizures

In the last decade Dr. Dean’s laboratory, sponsored by the Office of Naval Research Undersea Medicine Program, has helped shed light on the role of hyperbaric oxygen toxicity in triggering seizures. The condition can be a life-threatening by-product of breathing too much oxygen at high ambient pressures that impacts deep-sea divers as they swim deeper and longer.

Navy SEALs are especially at risk because they wear a closed circuit rebreather, to mitigate the narcotic and other debilitating effects of nitrogen and carbon dioxide breathed under increasing ocean pressure. The special device filters out these gases in such a way that bubbles do not appear on the water’s surface – useful in helping avoid enemy detection. However, the additional stealth comes at a cost. The ratio of oxygen the divers breathe greatly increases the deeper they plunge (essentially becoming pure oxygen) and, when combined with physical exertion and mission stress, can lead to nausea, dizziness, seizures, and even coma or death – all symptoms of oxygen toxicity.

Deep-sea divers can be at risk for oxygen toxicity seizures, a life-threatening condition caused by breathing too much oxygen at high ambient pressures. – U.S. Department of Defense photo

A possible countermeasure, anti-seizure sedatives, requires high doses that could impair warfighters’ mental and physical performance.

Without a reliable way to treat oxygen toxicity or predict which divers are more prone to seizures than others, the Navy takes rigorous precautions to restrict all divers to no more than 10 minutes in 50 feet of seawater.

“This risk of central nervous system oxygen toxicity limits oxygen’s use — not only in diving operations, but also its clinical applications in hyperbaric oxygen therapy,” Dr. Dean said.

Hyperbaric oxygen therapy, which increases blood oxygen to temporarily restore blood gases and tissue function, can help treat unhealed wounds, burns, crushing injuries, decompression sickness, carbon monoxide poisoning, and other medical conditions. The therapeutic benefit might be maximized if the doses of hyperbaric oxygen administered could be boosted without the risk of central nervous system oxygen toxicity.

In their search to find solutions, Dr. Dean and colleagues analyze the response of individual brain cells to the powerful effects of oxygen and other gases under altered pressure. In the laboratory’s hyperbaric chambers, they measure changes in brain cell membranes and electrical activity, and the damage of oxygen-induced free radicals.

An intracellular recording of the electrical signaling by a brain cell (middle trace) in a rodent brain slice that is stimulated by hyperbaric oxygen (top trace).

The researchers also monitor physiological changes in the breathing and heart rate of normal rats moving about in a chamber mimicking the environment of an increasingly deep dive. An electroencephalogram (EEG) shows electrical signals in the brain in real time, indicating the hyperexcitability that precedes and peaks with oxygen toxicity seizures.

Promising discoveries to predict, delay seizures

The USF group has made what could be a key discovery – the breathing rate of the rats exposed to pure oxygen increases several minutes before a seizure starts. “This may be a biomarker – a physiological signal that predicts the impending seizure,” Dr. Dean said.

If this early-predictor hypothesis bears out in larger animal models, Dr. Dean said, the next step would be to work with the Navy to devise and test a mask-fitted with a device designed to monitor divers’ breathing underwater. The ultimate aim: preventing oxygen-induced seizures to safely allow Navy SEALs to dive deeper and longer.

Another of the laboratory’s major findings evolved from an idea by Dr. Dean’s former postdoctoral fellow, Dominic D’Agostino, PhD, to harness the power of ketones, natural compounds produced by the body when it burns fat during periods of fasting or calorie restriction.

Dominic D’Agostino, PhD, associate professor of molecular pharmacology and physiology who collaborates with Dr. Dean, has expanded the laboratory’s research to include metabolic therapeutics. His group is investigating the combination of the ketogenic diet and/or ketone supplements with hyperbaric oxygen as a potential non-toxic cancer therapy.

Now an associate professor of molecular pharmacology and physiology, Dr. D’Agostino has focused on better understanding how the ketogenic diet — a special low-carbohydrate, high-fat diet that elevates blood ketones — produces anticonvulsive and neuroprotective effects. And, more recently he has worked with collaborators in academia and industry to develop and test naturally derived and synthetic supplements to boost blood ketones to mimic the ketogenic diet’s therapeutic effects.

Successfully used by physicians to treat drug-resistant epilepsy or other seizure disorders, the ketogenic diet shifts the brain’s energy source from glucose toward using ketones as a super fuel. However, it takes several days, or event weeks, for the body to adapt to this change in brain energy metabolism. That limitation and other problems associated with adhering to such a strict low-carbohydrate diet make nutritional ketosis less than ideal for Navy SEALs on a mission.

“The big advantage of putting the diet in a pill or liquid form is that you can achieve therapeutic ketosis in 30 minutes, instead of a week,” Dr. D’Agostino said.

A microscopic image of neurons hyper-excited by exposure to pure oxygen under high pressure in the hyperbaric chamber.

In a first of its kind study, Dr. D’Agostino tested whether feeding laboratory rats ketone esters and placing them in the hyperbaric chamber simulating underwater conditions could delay oxygen toxicity seizures. It worked.

More research is needed, but the experiments pave the way for a ketone supplement that would allow Navy SEALS to dive longer while protecting them against seizures, Dr. Dean said. “If what we’ve observed in rat model experiments holds true in humans, the Navy diver should be able to increase the amount of time spent at a depth of 50 feet of seawater (10 minutes) by 600 percent… which means that the divers could get more work done with fewer dives.”

“When the brain is running off ketones, it becomes much more resilient in terms of preserving brain energy and preventing a seizure,” Dr. D’Agostino said.

Based on research led by Dr. D’Agostino, USF has several patents pending for producing brain metabolism-enhancing ketone supplements, which may have a broad range of applications for neurodegenerative diseases like Alzheimer’s and ALS, diabetes and certain cancers as well as seizure disorders – all associated with impairments in metabolic regulation.

Earlier this year USF hosted the first international conference drawing doctors and researchers to discuss the effects of nutritional ketosis and metabolic therapeutics on the treatment of various diseases.

Stephanie Ciarlone, MS, a doctoral student in the USF Health Byrd Alzheimer’s Institute Laboratory of Edwin Weeber, PhD, (seated) professor of molecular pharmacology and physiology. Ciarlone’s preclinical studies of ketone esters in an Angelman syndrome mouse model are helping lay the foundation for what may be the first clinical trial of a USF-developed ketone ester in children with the rare neurogenetic disorder. — Photo by Sandra C. Roa, USF Health Communications

Among the presenters was Stephanie Ciarlone, MS, a doctoral student in the USF Health Byrd Alzheimer’s Institute laboratory of Edwin Weeber, PhD, where her research focuses on treatment options for Angelman syndrome, including ketone esters. This rare neuro-genetic disorder affects young children who commonly suffer debilitating drug-resistant seizures as the condition worsens.

With Dr. D’Agostino as a collaborator, a recent study by Ciarlone found that ketone supplements, without dietary restriction, delayed the onset of seizures and reduced the their number by 50 percent in a mouse model of Angelman syndrome. The ketone esters also improved learning and memory and motor coordination in the mice.

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Dr. Weeber, professor of molecular pharmacology and physiology, is working with Dr. D’Agostino to move their preclinical studies to the first clinical trial of a USF-developed ketone ester in children with Angelman syndrome. The study is expected to begin within a year.

From neuroprotection to exploring non-toxic cancer therapy

A serendipitous thing happened while Dr. D’Agostino and Angela Poff, PhD, research associate, were studying the neuroprotective effects of ketone supplements in different cell models. While examining cancer cells under a microsope specially designed to withstand the barometric pressure in the hyperbaric chamber, they observed that these cells were selectively vulnerable to high pressure oxygen at levels not harmful to healthy cells. They also noticed that the cancer cells did not proliferate when put in a petri dish with ketone supplements as a fuel source.

Cancer cells exhibit altered metabolic processes that could potentially be exploited to shut down their proliferation and survival. Solid tumors have areas of low oxygen, or hypoxia, that actually help promote a cancer’s aggressive growth. “So, the idea was that if we put more oxygen into the blood, which is what the hyperbaric oxygen chamber does, it will diffuse further into the tissue and help shut down areas promoting the tumor growth,” Dr. Poff said.

Angela Poff, PhD, research associate, led a study targeting cancer metabolism with hyperbaric oxygen and ketosis.

In addition, cancer cells use carbohydrate-derived glucose to generate most of their energy, so some research suggests a ketogenic diet that rigorously limits carbohydrates may help slow cancer’s growth, Dr. Poff said.

Armed with this two-pronged approach, the researchers embarked on their first cancer experiments in the Hyperbaric Lab. They discovered that combining hyperbaric oxygen and ketosis reduced the proliferation of metastatic cancer cells. Then, moving their research to a mouse model for aggressive metastatic cancer, they showed that combining a ketogenic diet and ketone supplements with hyperbaric oxygen therapy slowed tumor growth and doubled the survival time of the rodents. Their study was published online last year in PLOS ONE and the theory behind this approach was highlighted in an article in Carcinogenesis.

Hyperbaric oxygen by itself only slightly inhibited the spread of cancer in the mice. “But when we combined hyperbaric oxygen with ketosis induced by the ketogenic diet and our ketone ester, the potent synergistic effect was greater than the individual therapies alone,” Dr. Poff said. In particular, adding the ketone ester to the mix of the ketogenic diet and hyperbaric oxygen boosted the anti-cancer effects.

Images of rat brain slices used to study how hyperbaric oxygen disrupts brain cell function to cause seizures.

Next, the USF researchers say they will work on fine-tuning the combination therapy – finding what doses of ketone supplementation and levels of oxygen work to optimize the anti-cancer effects.

While more research is needed, Dr. D’Agostino said, “this combination therapy could represent a non-toxic strategy to help metabolically manage cancer and enhance the effectiveness of standard cancer treatment with chemotherapy and radiation.”

Dr. D’Agostino and Dr. Poff

The USF Hyperbaric Biomedical Research Laboratory houses various pressure chambers, including a 3.2-ton one specially designed for use with an atomic force microscope, which mimic the extreme environmental conditions challenging deep-sea divers.

The USF Hyperbaric Laboratory, including an interview with Dr. Dean, will be included in an upcoming independent documentary on nitrogen narcosis, a major limiting factor in the performance of deep-sea divers. The video will feature Sherri Ferguson of Simon Fraser University in British Columbia, who studies the health effects of narcosis in divers.

Video and photos by Katy Hennig, USF Health Office of Communications 

The mouse model study combined a ketogenic diet and supplements with hyperbaric oxygen therapy 

Tampa, FL (June 10, 2015) — A team of researchers from the Hyperbaric Biomedical Research Laboratory at the University of South Florida (USF) has doubled survival time in an aggressive metastatic cancer model using a novel combination of non-toxic dietary and hyperbaric oxygen therapies.

The study, “Non-toxic metabolic management of metastatic cancer in VM mice: Novel combination of ketogenic diet, ketone supplementation, and hyperbaric oxygen therapy,” was published online today in PLOS ONE.

Led by principal investigator Dominic D’Agostino, PhD, assistant professor in the Department of Molecular Pharmacology and Physiology at the USF Health Morsani College of Medicine, the recently published research shows the beneficial effects of using ketone supplements in conjunction with a non-toxic therapeutic regimen developed previously by the team.  Ketones are produced when the body begins burning fat instead of carbohydrates for energy.

Principal investigator Dominic D’Agostino, PhD, and research associate Angela Poff, PhD, measure tumor growth in the mice receiving the investigational treatment in USF’s Hyperbaric Biomedical Research Laboratory

The research group previously published a study in PLOS ONE demonstrating the anti-cancer effects of therapeutic ketosis induced by the high-fat, low-carbohydrate ketogenic diet (KD) combined with hyperbaric oxygen therapy (HBOT), which involves breathing high-pressure oxygen.  Inducing therapeutic ketosis solely with the ketogenic diet can be difficult, however, so the USF researchers created novel metabolic agents that induce ketosis without dietary restriction.  These ketone supplements slowed cancer growth on their own, and further enhanced the combined therapeutic effects of KD and HBOT.

In the recent USF study, mice with advanced metastatic cancer were fed either a standard high-carbohydrate diet or a carbohydrate-restricted ketogenic diet with ketone supplements and HBOT.  Therapeutic ketosis causes the body to shift from using glucose to fatty acids and ketones bodies for energy.

Normal healthy cells readily adapt to using ketone bodies for fuel, but most cancer cells lack this metabolic flexibility. Solid tumors also have areas of low oxygen, which promote tumor growth and metastatic spread.  HBOT involves breathing 100 percent oxygen at elevated barometric pressure, saturating the tumors with oxygen.  When administered properly, both ketosis and HBOT are non-toxic and may even protect healthy tissues while simultaneously damaging cancer cells.

Animals receiving the combination of KD, ketone supplements, and HBOT lived 103 percent longer than mice fed a standard high-carbohydrate diet. The researchers believe their study demonstrates the potential of these non-toxic therapies to contribute to current cancer treatment regimens and significantly improve the outcome of patients with advanced metastatic cancer.

Researchers at USF and elsewhere are investigating the potential benefits of the physiological state of therapeutic ketosis for several major diseases. The USF team believes these novel ketone supplements may be effective in other disorders besides cancer and have ongoing studies to test their potential use in wound healing, epilepsy, amyotrophic lateral sclerosis (ALS), Alzheimer’s disease, glucose transporter type 1 (GLUT1) deficiency syndrome, and exercise performance.

The cancer study, funded by a charitable donation from Scivation Inc., was inspired by the research of Professor Thomas Seyfried of Boston College.  Dr. Seyfried has advanced the theory that cancer is a metabolic disease, leading to the development of new strategies to treat and prevent cancer.  The USF researchers are currently collaborating with other scientists to explore options for establishing human clinical trials.

-USF Health-
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