(See commentary published in journal Cancer Metastasic and Reviews at https://rdcu.be/b33IN)
A drug discovered in the laboratories of Professors Charles Serhan of Harvard Medical School and Bruce Hammock of the University of California, Davis, may control the body's inflammatory response to COVID-10 and could help patients recover, according to a nine-member research team's newly published commentary in the journal Cancer Metastasis and Reviews, Springer Nature publishing group.
“COVID-19 results in excessive inflammation and a cytokine storm caused by the human body's reaction to the SARS-CoV-2 virus,” said lead author Dipak Panigrahy, a Harvard University physician and researcher who collaborates with the Hammock laboratory.
“Controlling the body's inflammatory response to COVID-19 will likely be as important as anti-viral therapies or a vaccine,” Panigraphy said. “Stimulation of inflammation resolutions via pro-resolution lipid mediators that are currently in clinical trials for other inflammatory diseases is a novel approach to turning off the inflammation and preventing the cytokine storm caused by COVID-19.”
“We propose that this drug will alleviate the cytokine storms that occur when the immune system is overwhelmed, when the patient is battling for survival,” Panigrahy said.
The drug is an inhibitor to the soluble epoxide hydrolase (sEH) enzyme, a key regulatory enzyme involved in the metabolism of fatty acids.
Editor-in-Chief and Professor Kenneth Honn selected their commentary, “Inflammation Resolution: a Dual-Pronged Approach to Averting Cytokine Storms in COVID-19?,” as the top paper of the month. The work is based on more than 40 years of eicosanoid research from the Hammock lab and more than 40 years of eicosanoid research from the Charles Serhan lab at Harvard Medical School.
“The tremendous cell destruction caused by COVID in the lungs leads to cell debris, activating a series of events leading to the cytokine storm and mortality,” Panigrahy said. “Controlling inflammation is key to resolving any intense infection, and thus, desired treatments should modulate and particularly resolve inflammation.”
“A rapid immune response is critical to controlling this virus,” Panigrahy emphasized.
“We believe it holds promise to combat the inflammation involved with this disease,” said co-author Hammock, a UC Davis distinguished professor who holds a joint appointment with the Department of Entomology and Nematology and the UC Davis Comprehensive Cancer Center. “It hit me in March that what we really need to do is not so much block cytokines as to move upstream to modulate them and resolve them rather than block inflammation.”
“We can increase the concentration of natural pro-resolving mediators termed EETs which act on a biological system to produce other pro-resolution mediators which modulate inflammation and actively resolve the process,” explained Hammock, who founded the Davis-based company EicOsis Human Health LLC, to bring the inhibitor to human clinical trials, which are underway in Texas.
“It is this resolution of inflammation and the subsequent repair that is critical to restore patient health,” said Serhan, whose studies with collaborator Sime show that immune resolution and repair are active processes in the lungs and other tissues. What drives the process, Serhan said, is the production of specific pro-resolving agents (SPMs).
Puch, who did research at the National Institutes of Health (NIH) on acute respiratory distress syndrome (ARDS) and sepsis, said the drug should be effective in treating ARDS, which she defined as “a respiratory failure characterized by rapid onset of widespread inflammation in the lungs and common among seriously ill COVID-19 patients.”
“We think there are a series of control systems that fail to modulate the patient's response in COVID,” Cortés-Puch said. “The severe outcomes in some patients from the virus infection often are attributed to the cytokine storm, and blocking these cytokines represents a major therapeutic effort, which so far has failed. Our view is that we can move several steps upstream and control the cytokine storm not just at the level of individual cytokines and in doing so, we can encourage resolution of inflammation. In doing so, we can encourage resolution of inflammation.”
Said William Schmidt, EicOsis vice president of clinical development: “Our drug candidate has not caused any adverse effects at high doses in diabetic-hypertensive patients. Since this soluble epoxide hydrolase inhibitor acts upstream to down-regulate the eicosanoid and the cytokine storm, we are optimistic that it can help patients.” The Federal Drug Administration recently granted another EicOsis drug candidate a “fast track” status.
“In the meantime, we are looking at blood markers through time that are helping us to see the order of events leading from the original virus infection to the severe organ damage and cytokine storm that occurs in the most severe cases,” said Cindy McReynolds, a UC Davis doctoral student in pharmacology/toxicology, and EicOsis project manager.
Hammock said the UC Davis team began researching cytokine storms 16 years ago in projects based on the thesis of former doctoral student Kara Schmelzer. Now the UC Davis and Harvard scientists are targeting COVID-19.
Said Hammock: “In March, Cindy, Irene and I worked on a grant proposal with a group of scientists from the European Union to combine an anti-viral agent with an anti-inflammatory agent.”
“It hit me at that time,” Hammock reiterated, “that what we really need to do is not so much block cytokines as to move upstream to modulate them and resolve rather than block inflammation. We are lucky to have been working on such a resolving agent at UC Davis for decades.”
Other co-authors of the paper are Molly Gilligan and Allison Gartung of the Panigrahy lab; Sui Huang of the Institute for Systems Biology, Seattle; and Richard Phipps, independent scholar, Richmond, Va.
Much of the research was funded by NIH grants, including a National Institute of Environmental Health Science (River Award) to Hammock. The Panigrahy laboratory is generously supported by the Credit Unions Kids at Heart Team; the C.J. Buckley Pediatric Brain Tumor Fund; and the Joe Andruzzi Foundation.
Severe coronavirus disease (COVID-19) is characterized by pulmonary hyper-inflammation and potentially life-threatening “cytokine storms”. Controlling the local and systemic inflammatory response in COVID-19 may be as important as anti-viral therapies. Endogenous lipid autacoid mediators, referred to as eicosanoids, play a critical role in the induction of inflammation and pro-inflammatory cytokine production. SARS-CoV-2 may trigger a cell death (“debris”)-induced “eicosanoid storm”, including prostaglandins and leukotrienes, which in turn initiates a robust inflammatory response. A paradigm shift is emerging in our understanding of the resolution of inflammation as an active biochemical process with the discovery of novel endogenous specialized pro-resolving lipid autacoid mediators (SPMs), such as resolvins. Resolvins and other SPMs stimulate macrophage-mediated clearance of debris and counter pro-inflammatory cytokine production, a process called inflammation resolution. SPMs and their lipid precursors exhibit anti-viral activity at nanogram doses in the setting of influenza without being immunosuppressive. SPMs also promote anti-viral B cell antibodies and lymphocyte activity, highlighting their potential use in the treatment of COVID-19. Soluble epoxide hydrolase (sEH) inhibitors stabilize arachidonic acid-derived epoxyeicosatrienoic acids (EETs), which also stimulate inflammation resolution by promoting the production of pro-resolution mediators, activating anti-inflammatory processes, and preventing the cytokine storm. Both resolvins and EETs also attenuate pathological thrombosis and promote clot removal, which is emerging as a key pathology of COVID-19 infection. Thus, both SPMs and sEH inhibitors may promote the resolution of inflammation in COVID-19, thereby reducing acute respiratory distress syndrome (ARDS) and other life-threatening complications associated with robust viral-induced inflammation. While most COVID-19 clinical trials focus on “anti-viral” and “anti-inflammatory” strategies, stimulating inflammation resolution is a novel host-centric therapeutic avenue. Importantly, SPMs and sEH inhibitors are currently in clinical trials for other inflammatory diseases and could be rapidly translated for the management of COVID-19 via debris clearance and inflammatory cytokine suppression. Here, we discuss using pro-resolution mediators as a potential complement to current anti-viral strategies for COVID-19.
EicOsis LLC, a company founded by UC Davis distinguished professor Bruce Hammock to develop a non-opiate drug to relieve inflammatory pain in companion animals and target chronic neuropathic pain in humans and horses, can now add “Sacramento Region Innovator of the Year” to its list of accomplishments.
EicOsis won the award in the medical health/biopharmaceutical category of the annual Sacramento Region Innovation Awards Program. The program “recognizes the area's vibrant innovation community—from emerging to established companies—and their breakthrough creations,” according to sponsors Stoel Rives LLP, Moss Adams LLP and the Sacramento Business Journal.
“This project is an illustration of how fundamental science leads to real world applications, in this case addressing severe pain of humans and companion animals,” said Hammock, chief executive officer of EicOsis and a UC Davis faculty member who holds a joint appointment with the Department of Entomology and Nematology and the UC Davis Comprehensive Cancer Center. “Our success in translation has been due largely to support from a number of institutes of the National Institutes of Health and a small team of hard-working scientists.”
The ceremony, honoring the winners of the eight categories, took place Nov. 7 in the Crest Theatre, Sacramento. Judges scored the finalists on novelty, market need, economic or social impact and disruption.
“It was an honor to be awarded the Sacramento Region Innovator of the Year in Medical Health and BioPharma,” said Cindy McReynolds, senior program manager of EicOsis and a UC Davis doctoral candidate studying pharmacology and toxicology. “The companies represented were inspiring, and it is great to be a part of the innovation going on in the Sacramento region.”
“Chronic pain is an enormous emotional and economic burden for more than 100 million people in the United States alone,” said Hammock, who co-founded EicOsis in December 2011 to alleviate pain in humans and companion animals. “The extreme and poorly treated pain that I observed as a medical officer working in a burn clinic in the Army, is a major driver for me to translate my research to help patients with severe pain.”
Phase 1 human clinical trials to test the drug candidate, EC5026, a first-in-class, small molecule that potently inhibitssEH, will begin Dec. 10 in Texas. The title: "A Single-Center, Double-Blind, Placebo-Controlled, Phase 1a Single Ascending Dose Study to Investigate the Safety, Tolerability, and Pharmacokinetics of Sequential Dose Regiments of Oral EC5026 in Healthy Male and Female Subjects." Eight will participate; six with the drug candidate and two with the placebo. The technology was discovered in the Hammock lab and UC Davis has licensed patents exclusively to EicOsis.
“EC5026 is a key regulatory enzyme involved in the metabolism of membrane fatty acids,” Hammock said. "It's a novel, non-opioid and oral therapy for neuropathic and inflammatory pain. Inhibition of sEH treats pain by stabilizing natural analgesic and anti-inflammatory mediators."
The project is unique in that “there have been very few truly new types of analgesic compounds that have reached the market in the past 50 years,” Hammock said.
“The sEH enzyme is involved in regulating the activity of powerful anti-inflammatory fatty acids called EETs that are present in all cells in humans and animals,” the scientists explained in their awards application. “EETs are anti-inflammatory, analgesic, anti-hypertensive, but they are short lived molecules that are normally eliminated within seconds. By inhibiting sEH, EET levels can be increased by 4x or more and maintained at high anti-inflammatory and analgesic levels for 24 hours or longer.”
“The sEH inhibitors are very potent molecules that are designed for once daily oral dosing. They can also be administered intravenously for acute pain (e.g. equine laminitis),” they wrote. “Preclinical safety studies show that sEH inhibitors are very safe with no visible signs of toxicity at doses more than 100x higher than the therapeutic dose levels. Unlike conventional analgesics, they do not produce sedation or cognitive dysfunction and they have been shown to have no addiction liability, no adverse cardiovascular effects, and no adverse effects on the gastrointestinal tract. They can be safely co-administered with existing analgesic medications.”
Approximately 50 million Americans (20 percent of the population) suffer from chronic pain, according to the Center for Disease Control and Prevention. The annual economic toll is $560 billion, encompassing direct medical expenses, lost productivity, and disability claims. Pain research is now one of the top priorities of the National Institutes of Health (NIH).
EicOsis advancement of EC5026 into clinical trials has been funded as part of the Blueprint Neurotherapeutics Network (BPN) of the NIH Blueprint for Neuroscience Research. The BPN is a collaboration of NIH Institutes and Centers that supports innovative research on the nervous system with the goal of developing new neurotherapeutic drugs.
EicOsis (pronounced eye-cosis), derives its name from eicosanoid, “the major backbone of chemical mediators in the arachidonate cascade,” said McReynolds. “It symbolizes the epoxide group in chemistry, which is key to the anti-inflammatory chemical mediators and where the biochemical target called soluble epoxide hydrolase works.”
A Davis-based company founded by UC Davis distinguished professor Bruce Hammock has received the green light to begin Phase 1 clinical trials to test a non-narcotic drug candidate developed in the Hammock lab to alleviate chronic pain.
EicOsis LLC, a pharmaceutical startup, has received Investigational New Drug (IND) approval from the U.S. Food and Drug Administration to test the drug candidate, EC5026. Clinical trials are expected to begin this year.
"EicOsis is developing a new class of oral non-narcotic analgesics based on inhibition of the soluble epoxide hydrolase (sEH) enzyme," said EicOsis chief executive officer Hammock, who holds a joint appointment with the UC Davis Department of Entomology and Nematology and the UC Davis Comprehensive Cancer Center. UC Davis has licensed EC5026 exclusively to EicOsis.
EC5026 (BPN-19186) is described as a first-in-class, small molecule that potently inhibits soluble epoxide hydrolase (sEH). "It is key regulatory enzyme involved in the metabolism of membrane fatty acids," Hammock said. "Inhibition of sEH treats pain by stabilizing natural analgesic and anti-inflammatory mediators."
The sEH inhibitors developed by EicOsis have already shown to be effective for inflammatory and neuropathic pain in the rodents, horses, dogs and cats, with no apparent adverse or addictive reactions.
“Chronic pain management is a serious public health crisis with few options available that provide effective relief free of life-threatening safety concerns including abuse,” said UC Davis physician Scott Fishman, the Fullerton Endowed Chair in the Department of Anesthesiology and Pain Medicine, and professor and director of the Center for Advancing Pain Relief at the UC Davis School of Medicine. “The medical community is continually seeking effective pain management strategies. EicOsis's new compound is a novel pharmacological approach for treating pain, and I remain optimistic for its success.”
Approximately 50 million Americans (20 percent of the population) suffer from chronic pain, according to the Center for Disease Control and Prevention (CDC). The annual economic toll is $560 billion, encompassing direct medical expenses, lost productivity, and disability claims. Pain research is now one of the top priorities of the National Institutes of Health (NIH).
EicOsis advancement of EC5026 into clinical trials has been funded as part of the Blueprint Neurotherapeutics Network (BPN) of the NIH Blueprint for Neuroscience Research. The BPN is a collaboration of NIH Institutes and Centers that supports innovative research on the nervous system with the goal of developing new neurotherapeutic drugs.
“There is clear unmet need for new pain therapeutics," said BPN Program Director Charles L. Cywin. "sEH is an important pain target in our portfolio and we are excited to see EC5026 advance to human clinical development on the pathway to treating patients."
The development of EC5026 also drew financial support from the Helping to End Addiction Long-term, or the NIH HEAL Initiative via a grant to EicOsis, which is using the funds to de-risk the development process of EC5026 and to accelerate the start of clinical trials.
"It's clear that a multi-pronged scientific approach is needed to reduce the risks of opioids, accelerate development of effective non-opioid therapies for pain and provide more flexible and effective options for treating addiction to opioids,” said NIH Director Francis S. Collins, who launched the initiative in early 2018. “This unprecedented investment in the NIH HEAL Initiative demonstrates the commitment to reversing this devastating crisis.”
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The drug candidate, known as EC5026, targets a novel pathway to block the underlying cause of certain types of pain. Described by EicOsis as a “novel, non-opioid and oral therapy for neuropathic and inflammatory pain,” it is an inhibitor to the soluble epoxide hydrolase (sEH) enzyme, a key regulatory enzyme involved in the metabolism of fatty acids. UC Davis recently licensed certain patents supporting the underlying technology exclusively to EicOsis.
Clinical trials are expected to begin this summer. “The clinical trials would be the world's first clinical evaluation of sEH for pain,” said William Schmidt, EicOsis vice president of clinical development, who has focused his entire professional career on developing novel pain medicines. “I am thrilled that we have a drug candidate lacking the side effects of both opioids and non-steroidal anti-inflammatory drugs that can potentially produce lead to an entirely new way to treat chronic pain.”
“Chronic pain is an enormous emotional and economic burden for more than 100 million people in the United States alone,” said Hammock, a UC Davis a distinguished professor who holds a joint appointment with the Department of Entomology and Nematology and the UC Davis Comprehensive Cancer Center. He co-founded EicOsis in December 2011 to alleviate pain in humans and companion animals. “The extreme and poorly treated pain that I observed as a medical officer working in a burn clinic in the Army, is a major driver for me to translate my research to help patients with severe pain.”
National statistics show that as many as eight out of every 10 American adults suffer from chronic pain; three out of four patients consider their therapies for pain ineffective; and as many as a third of the opioid-prescribed patients misuse them.
Every day, more than 130 people in the United States die from opioid overdose, according to the National Institute of Drug Abuse. The Centers for Disease Control and Prevention estimates that the total economic burden of prescription opioid misuse alone in the United States is $78.5 billion a year. That includes the costs of health care, lost productivity, addiction treatment, and criminal justice involvement.
“This completes the fundraising for Phase 1 of the clinical development program of this novel pain therapeutic,” said Hammock. “We are particularly pleased that the support came from Open Philanthropy with its history of both financially successful and socially important investments.”
Dushyant Pathak, UC Davis associate vice chancellor for Research and executive director of Venture Catalyst, lauded the achievement. “We are very pleased to see the achievement of this important business milestone by EicOsis,” Pathak said. “It's especially heartening to see the entrepreneurial persistence of Bruce Hammock being recognized by Open Philanthropy.”
Open Philanthropy identifies outstanding investment opportunities and makes grants based on importance, need, and tractability, according to the organization's scientific advisors Chris Somerville and Heather Youngs. They said Open Philanthropy selected the Davis project because the EicOsis drug “may reduce suffering from chronic pain conditions which are severe in both developed and developing nations.”
On its website, http://www.eicosis.com, EicOsis depicts itself as “a privately held company developing a first-in-class therapy of a once daily, oral treatment for neuropathic and inflammatory pain in humans and companion animals.”
“Our orally active compounds stabilize natural regulatory mediators in the body that reduce endoplasmic reticulum stress, which, in turn, appears to cause a variety of chronic diseases,” said EicOsis neurobiologist Karen Wagner. “The EicOsis compounds represent a new mechanism of action that both resolves inflammation and reduces pain.”
EicOsis (pronounced eye-cosis), derives its name from eicosanoid, “the major backbone of chemical mediators in the arachidonate cascade,” said Cindy McReynolds, an EicOsis project manager and a doctoral student in pharmacology and toxicology at UC Davis. “It symbolizes the epoxide group in chemistry, which is key to the anti-inflammatory chemical mediators and where the biochemical target called soluble epoxide hydrolase works.”
The National Institutes of Health (NIH) Blueprint for Neuroscience Research (Blueprint) awarded EicOsis a $4 million grant to advance compounds through Phase 1 clinical trials for diabetic neuropathic pain. A goal of the Blueprint Neurotherapeutics Network is to discover, develop and generate novel compounds that will ultimately be commercialized and benefit humankind.
In addition, EicOsis received support from the NIH's National Institute of Neurological Disorders and Stroke (NINDS), and the support of two small business programs affiliated with the National Institute of Environmental Sciences: the Small Business Innovation Research (SBIR) and the Small Business Technology Transfer (STTR).
“We are fortunate to receive all this support in the development of our oral medication for pain treatment through human Phase 1a trials, and now Open Philanthropy through human Phase 1b trials and beyond,” said Alan Buckpitt, a UC Davis retired professor of veterinary pharmacology and toxicology, and a principal investigator on the grants.
Nationally recognized for his achievements, Hammock is a fellow of the National Academy of Inventors, which honors academic invention and encourages translations of inventions to benefit society. He is a member of the U.S. National Academy of Sciences, a fellow of the Entomological Society of America, and the recipient of scores of awards, including the first McGiff Memorial Awardee in Lipid Biochemistry; and the Bernard B. Brodie Award in Drug Metabolism, sponsored by the America Society for Pharmacology and Experimental Therapeutics.
Hammock, a member of the UC Davis faculty since 1980, received his doctorate in entomology and toxicology from UC Berkeley. He traces the history of his enzyme research to 1969 during his graduate student days in the John Casida laboratory. Hammock was researching insect developmental biology and green insecticides when he and colleague Sarjeet Gill, now a distinguished professor at UC Riverside, discovered the target enzyme in mammals that regulates epoxy fatty acids.
“My research led to the discovery that many regulatory molecules are controlled as much by degradation and biosynthesis,” Hammock said. “The epoxy fatty acids control blood pressure, fibrosis, immunity, tissue growth, depression, pain and inflammation to name a few processes.”
“Basically, I began by trying to figure out how a key enzyme, epoxide hydrolase, degrades a caterpillar's juvenile hormone, leading to metamorphosis from the larval stage to the adult insect,” Hammock. He asked himself these questions: “Does the enzyme occur in plants? Does it occur in mammals?" It does, and particularly as a soluble epoxide hydrolase in mammals.
"It is always important to realize that the most significant translational science we do in the university is fundamental science,” said Hammock, marveling that “this all began by asking how caterpillars turn into butterflies.”
An enzyme inhibitor developed in the UC Davis laboratory of Bruce Hammock and tested in mice by a team of international researchers shows promise that it could lead to a drug to prevent or reduce the disabilities associated with the neurodevelopmental disorders of autism and schizophrenia.
“We discovered that soluble epoxide hydrolase (sEH) plays a key role in inflammation associated with neurodevelopmental disorders. Inhibiting that enzyme stops the inflammation and the development of autism-like and schizophrenia-like symptoms in animal models,” said collaborator Kenji Hashimoto, a professor with the Chiba University Center for Forensic Mental Health, Japan. The scientists found higher levels of sEH in a key region of the brain—the prefrontal cortex of juvenile offspring-- after maternal immune activation (MIA).
“Mothers who have MIA, which results from severe stress in that region of the brain, have an increased occurrence of neurodevelopment disorders in their offspring,” Hashimoto explained. “In our study, the sEH enzyme increased dramatically in a key brain region of mice pups from mothers with MIA.”
The research, published today (March 18) in the Proceedings of the National Academy of Sciences (PNAS), is the work of 14 researchers from Chiba University Center for Forensic Mental Health; the Laboratory for Molecular Psychiatry, RIKEN Center for Brain Science, in Wako, Saitama, Japan; and the Hammock laboratory.
Research in Mice Pups
By inhibiting sEH, the researchers reversed cognitive and social interaction deficiencies in the mice pups. They hypothesize that this is due to increasing natural chemicals, which prevent brain inflammation. In people, this could reduce the disabilities associated with autism, such as anxiety, gastrointestinal disturbances and epilepsy.
“The same chemical and biochemical markers behaved as predicted in human stem cells,” said Hammock, a distinguished professor who holds a joint appointment with the Department of Entomology and Nematology and the UC Davis Comprehensive Cancer Center.
Earlier studies have indicated a genetic disposition to the disorders. The team also studied postmortem brain samples from autism patients that confirmed the alterations.
“In the case of both autism and schizophrenia, the epidemiology suggests that both genetics and environment are contributing factors,” said neuroscientist and associate professor Amy Ramsey of the Department of Pharmacology and Toxicology, University of Toronto, who was not involved in the study. “In both cases, maternal infection is a risk factor that might tip the scales for a fetus with a genetic vulnerability. This study is important because it shows that their drug can effectively prevent some of the negative outcomes that occur with prenatal infections. While there are many studies that must be done to ensure its safe use in pregnant women, it could mitigate the neurological impacts of infection during pregnancy.”
Neuroscientist Lawrence David, professor and chair of the School of Public Health, University of Albany, N.Y., who was not involved in the research, said that the study might lead to “an important therapeutic intervention for neurodevelopment disorders.”
Might Be Important Therapeutic Invervention
“There is increasing evidence that maternal immune activation activities (MIA) during fetal development can lead to aberrant neurobehaviors, including autistic-like activities,” said Lawrence, who studies neuroimmunology and immunotoxicology. The study “suggests that enzymatic control of fatty acid metabolism is implicated in neuroinflammation associated with schizophrenia and autism spectrum disorders. The expression of Ephx2 giving rise to soluble epoxide hydrolase (sEH) influences production of fatty acid metabolites, which elevate inflammation in the experimental model of mice after MIA; the sEH inhibitor TPPU (N-[1-(1-oxopropyl)-4-piperidinyl]-N'-[4-(trifluoromethoxy)phenyl)-urea) was postnatally used to improved behaviors. Analysis of cadaver brains from individuals with ASD also expressed increased sEH. Fatty acid metabolites have been known to affect fetal development, especially that of the brain; therefore, TPPU might be an important therapeutic intervention for neurodevelopmental disorders.”
Molecular bioscientist Isaac Pessah of the UC Davis School of Veterinary Medicine, distinguished professor and associate dean of research and graduate education in the Department of Molecular Biosciences, described the findings as “significant” and called for more detailed and expanded studies.
“There is mounting evidence that inappropriate maternal immune responses during pregnancy to infection contributes elevated risk to autism spectrum disorder, at least in a fraction of cases,” Pessah said. “The most significant findings reported here is that a commonly used mouse model of immune-triggered behavioral deficits mimicking some of the core symptoms in autistic children can be suppressed by inhibiting a novel biochemical target, soluble epoxide hydrolase; a target not previously explored as a target for therapeutic intervention to treat ASDs. These findings provide a rational basis for more detailed and expanded studies in mice carrying mutations implicated in ASDs to determine whether the therapeutic benefits of soluble epoxide hydrolase inhibitor(s) observed in this study are more generalizable.”
Autism in the United States
The Center for Disease Control and Prevention (CDC) estimates that 1 in 68 children in the United States have autism, commonly diagnosed around age 3. It is four times more common in boys than girls. CDC defines autism spectrum disorder as a “developmental disability that can cause significant social, communication and behavioral challenges.” The disorder impairs the ability to communicate and interact.
Approximately 3.5 million people or 1.2 percent of the population in the United States are diagnosed with schizophrenia, one of the leading causes of disability, according to the Schizophrenia and Related Disorders Alliance of America (SARDAA). Scores more go unreported. Approximately three-quarters of persons with schizophrenia develop the illness between 16 and 25 years of age. Statistics also show that between one-third and one half of all homeless adults have schizophrenia, and 50 percent of people diagnosed have received no treatment. Among the symptoms: delusions, hallucinations, disorganized speech, disorganized or catatonic behavior, and obsessive-compulsive disorders, such as hoarding, according to SARDAA.
Promising Prophylactic or Theraputic Target
In their research paper, titled “Key Role of Soluble Epoxide Hydrolase in the Neurodevelopmental Disorders of Offspring After Maternal Immune Activation,” the scientists described sEH as “a promising prophylactic or therapeutic target for neurodevelopmental disorders in offspring after MIA.”
First author Min Ma and second Qian Ren of the Hashimoto lab conducted the animal and biochemical work, while chemists Jun Yang and Sung Hee Hwang of the Hammock lab performed the chemistry and analytical chemistry. Takeo Yoshikawa, a team leader with the RIKEN's Molecular Psychiatry Laboratory, performed measurements of gene expression in the neurospheres from iPSC (induced pluripotent stem cells) from schizophrenia patients and postmortem brain samples from autism patients.
Hashimoto described the international collaboration as “exciting and productive.” This is their third PNAS paper in a series leading to endoplasmic reticulum stress. “We report discovery of a biochemical axis that leads to multiple neurological disorders, including depression, Parkinson's disease, schizophrenia, autism spectrum disorders and similar diseases,” he said.
First Human Trials
William Schmidt, vice president of clinical development at EicOsis, a Davis-based company developing inhibitors to sEH to treat unmet medical needs in humans and companion animals, said the company is developing a first-in-class therapy for neuropathic and inflammatory pain. “EicOsis is in the process of finalizing our first human trials on the inhibitors of the soluble epoxide hydrolase, originally reported from UC Davis,” Schmidt said. “We are targeting the compounds as opioid replacements to treat peripheral neuropathic pain. It is exciting that the same compound series may be used to prevent or treat diseases of the central nervous system.”
Several grants from the National Institutes of Health, awarded to Hammock, supported the research. Hammock praised the many collaborators and students he has worked with on the project. “This work illustrates the value of research universities in bringing together the diverse talent needed to address complex problems,” Hammock said. “It also illustrates the value of fundamental science. This autism research can be traced directly to the fundamental question of how caterpillars turn into butterflies.”
Now working solely on research to benefit humankind, Hammock began his career in insect science at UC Berkeley where he investigated how epoxide hydrolase degrades a caterpillar's juvenile hormone. The process leads to metamorphosis from the larval stage to the adult insect. Hammock then wondered "Does the enzyme occur in plants? Does it occur in mammals?"
It does, and particularly as a soluble epoxide hydrolase in mammals.
"Science is full of surprises," said Hammock, who founded EicOsis to help human patients conquer pain without opioids. "We need to remember that the concept, the clinical target, and even the chemical structure, came from asking how caterpillars turn into butterflies."
ABSTRACT, PNAS Paper, "Key Role of Soluble Epoxide Hydrolase in the Neurodevelopmental Disorders of Offspring After Maternal Immune Activation"
“Maternal infection during pregnancy increases the risk of neurodevelopmental disorders such as schizophrenia and autism spectrum disorder (ASD) in offspring. In rodents, maternal immune activation (MIA) yields offspring with schizophrenia- and ASD-like behavioral abnormalities. Soluble epoxide hydrolase (sEH) plays a key role in inflammation associated with neurodevelopmental disorders. Here we found higher levels of sEH in the prefrontal cortex (PFC) of juvenile offspring after MIA. Oxylipin analysis showed decreased levels of epoxy-fatty acids in the PFC of juvenile offspring after MIA, supporting increased activity of sEH in the PFC of juvenile offspring. Furthermore, the expression of sEH (or EPHX2) mRNA in iPSC-derived neurospheres from schizophrenia patients with the 22q11.2 deletion was higher than that of healthy controls. Moreover, the expression of EPHX2 mRNA in the postmortem brain samples (Brodmann area 9 and 40) from ASD patients was higher than that of controls. Treatment of TPPU (a potent sEH inhibitor) into juvenile offspring from P28 to P56 could prevent cognitive deficits and loss of parvalbumin (PV)-immunoreactivity in the medial PFC of adult offspring after MIA. In addition, dosing of TPPU to pregnant mothers from E5 to P21 could prevent cognitive deficits, and social interaction deficits and PV-immunoreactivity in the mPFC of juvenile offspring after MIA. These findings suggest that increased activity of sEH in the PFC plays a key role in the etiology of neurodevelopmental disorders in offspring after MIA. Therefore, sEH would represent a promising prophylactic or therapeutic target for neurodevelopmental disorders in offspring after MIA.”
Related Research Published in PNAS
- Soluble Epoxide Hydrolase Plays a Key Role in the Pathogenesis of Parkinson's Disease
- Gene Deficiency and Pharmacological Inhibition of Soluble Epoxide Hydrolase Confers Resilience to Repeated Social Defeat Stress