Francis "Frank" Vincent Chisari (born 5 April 1942 in New York City) [1] is a physician, experimental pathologist, and viral immunologist, known for his research on virus-host interactions and disease pathogenesis during hepatitis B and hepatitis C virus infections. [2]
Chisari earned a bachelor's degree in biology magna cum laude from Fordham University in 1963 and an M.D. from Weill Cornell Medical College in 1968. His postgraduate training included an internship in Internal Medicine at New York Hospital (1968-69), residency in anatomic pathology at the Mayo Clinic (1969-70), a staff associate position in immunopathology at the NIH (1970-72), residency in internal medicine at Dartmouth-Hitchcock Medical Center (1972-73), and a Postdoctoral Research Fellowship in immunopathology at Scripps Clinic and Research Foundation (1973-75). He joined the Scripps Faculty as an Assistant Professor (1975-81), progressing to Associate Professor (1981-88) during which he spent a sabbatical year (1983-1984) as a Fogarty Scholar in molecular biology at the Institut Pasteur, [3] and Full Professor from 1988 until retiring as Professor Emeritus in 2015.
During his tenure at Scripps, Chisari's NIH-funded research focused on the immunological basis for viral clearance and disease pathogenesis during acute and persistent hepatitis B virus (HBV) and hepatitis C virus (HCV) infections; the signaling pathways and effector molecules that mediate these antiviral and pathogenic effects; and the viral evasion strategies that subvert them. His laboratory developed cell-based and animal models of HBV and HCV infection and performed foundational studies elucidating the T-cell response to these viruses in infected humans, subhuman primates, and transgenic mice.
Chisari is best known for demonstrating that chronic immune-mediated injury and inflammation can cause liver cancer, and for discovering that antiviral T cells can purge viruses from infected cells noncytolytically by secreting antiviral cytokines that inhibit viral replication, thus controlling and even eradicating the infection while preserving the vital functions of the infected cells. Those studies established a new paradigm in viral pathogenesis and immunobiology which has informed the pursuit of novel immunotherapeutic approaches for the prevention and treatment of chronic HBV and other viral infections. [4]
In the HCV arena, his laboratory developed a cell culture system capable of supporting the entire HCV life cycle; identified a novel mechanism for viral spread via exosomal delivery of HCV genomic RNA from infected hepatocytes to uninfected hepatocytes masked by the exosome from detection by antiviral antibodies; and they discovered that HCV genomic RNA-containing exosomes can trigger an innate host response by activating plasmacytoid dendritic cells to produce antiviral cytokines that can suppress viral spread.
In addition to his basic research, from 1988 to 2004 Chisari served as Director of an NIH-funded General Clinical Research Center where he and other Scripps scientists and clinicians performed a wide variety of peer-reviewed clinical studies of patients with viral infections, autoimmune diseases, multiple sclerosis, sleep disorders, metabolic diseases and cancer.
Chisari has lectured widely internationally; he has served on the editorial boards of several distinguished scientific journals; and he holds numerous patents on the use of viral peptide epitopes to treat and to prevent hepatitis-B or hepatitis-C virus infections. [5] In recognition of his contributions, Chisari has received numerous honors and awards, including those listed below.
Interferons are a group of signaling proteins made and released by host cells in response to the presence of several viruses. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten their anti-viral defenses.
Antiviral drugs are a class of medication used for treating viral infections. Most antivirals target specific viruses, while a broad-spectrum antiviral is effective against a wide range of viruses. Antiviral drugs are a class of antimicrobials, a larger group which also includes antibiotic, antifungal and antiparasitic drugs, or antiviral drugs based on monoclonal antibodies. Most antivirals are considered relatively harmless to the host, and therefore can be used to treat infections. They should be distinguished from virucides, which are not medication but deactivate or destroy virus particles, either inside or outside the body. Natural virucides are produced by some plants such as eucalyptus and Australian tea trees.
Hepatitis D is a type of viral hepatitis caused by the hepatitis delta virus (HDV). HDV is one of five known hepatitis viruses: A, B, C, D, and E. HDV is considered to be a satellite because it can propagate only in the presence of the hepatitis B virus (HBV). Transmission of HDV can occur either via simultaneous infection with HBV (coinfection) or superimposed on chronic hepatitis B or hepatitis B carrier state (superinfection).
Hepadnaviridae is a family of viruses. Humans, apes, and birds serve as natural hosts. There are currently 18 species in this family, divided among 5 genera. Its best-known member is hepatitis B virus. Diseases associated with this family include: liver infections, such as hepatitis, hepatocellular carcinomas, and cirrhosis. It is the sole accepted family in the order Blubervirales.
Viral hepatitis is liver inflammation due to a viral infection. It may present in acute form as a recent infection with relatively rapid onset, or in chronic form, typically progressing from a long-lasting asymptomatic condition up to a decompensated hepatic disease and hepatocellular carcinoma (HCC).
The hepatitis C virus (HCV) is a small, enveloped, positive-sense single-stranded RNA virus of the family Flaviviridae. The hepatitis C virus is the cause of hepatitis C and some cancers such as liver cancer and lymphomas in humans.
Hepacivirus is a genus of positive-strand RNA viruses in the family Flaviviridae. The hepatitis C virus (HCV), in species Hepacivirus C, infects humans and is associated with hepatitis and hepatocellular carcinoma. There are fourteen species in the genus which infect a range of other vertebrate.
Murine coronavirus (M-CoV) is a virus in the genus Betacoronavirus that infects mice. Belonging to the subgenus Embecovirus, murine coronavirus strains are enterotropic or polytropic. Enterotropic strains include mouse hepatitis virus (MHV) strains D, Y, RI, and DVIM, whereas polytropic strains, such as JHM and A59, primarily cause hepatitis, enteritis, and encephalitis. Murine coronavirus is an important pathogen in the laboratory mouse and the laboratory rat. It is the most studied coronavirus in animals other than humans, and has been used as an animal disease model for many virological and clinical studies.
Vincent R. Racaniello is a Higgins Professor in the Department of Microbiology and Immunology at Columbia University's College of Physicians and Surgeons. He is a co-author of a textbook on virology, Principles of Virology.
Mitochondrial antiviral-signaling protein (MAVS) is a protein that is essential for antiviral innate immunity. MAVS is located in the outer membrane of the mitochondria, peroxisomes, and mitochondrial-associated endoplasmic reticulum membrane (MAM). Upon viral infection, a group of cytosolic proteins will detect the presence of the virus and bind to MAVS, thereby activating MAVS. The activation of MAVS leads the virally infected cell to secrete cytokines. This induces an immune response which kills the host's virally infected cells, resulting in clearance of the virus.
Hepatitis B is an infectious disease caused by the hepatitis B virus (HBV) that affects the liver; it is a type of viral hepatitis. It can cause both acute and chronic infection.
Nonstructural protein 5A (NS5A) is a zinc-binding and proline-rich hydrophilic phosphoprotein that plays a key role in Hepatitis C virus RNA replication. It appears to be a dimeric form without trans-membrane helices.
HBx is a hepatitis B viral protein. It is 154 amino acids long and interferes with transcription, signal transduction, cell cycle progress, protein degradation, apoptosis and chromosomal stability in the host. It forms a heterodimeric complex with its cellular target protein, and this interaction dysregulates centrosome dynamics and mitotic spindle formation. It interacts with DDB1 redirecting the ubiquitin ligase activity of the CUL4-DDB1 E3 complexes, which are intimately involved in the intracellular regulation of DNA replication and repair, transcription and signal transduction.
Hepatitis B virus (HBV) is a partially double-stranded DNA virus, a species of the genus Orthohepadnavirus and a member of the Hepadnaviridae family of viruses. This virus causes the disease hepatitis B.
miR-122 is a miRNA that is conserved among vertebrate species. miR-122 is not present in invertebrates, and no close paralogs of miR-122 have been detected. miR-122 is highly expressed in the liver, where it has been implicated as a regulator of fatty-acid metabolism in mouse studies. Reduced miR-122 levels are associated with hepatocellular carcinoma. miR-122 also plays an important positive role in the regulation of hepatitis C virus replication.
Stuart C. Ray is an American physician. He is Vice Chair of Medicine for Data Integrity and Analytics, Associate Director of the Infectious Diseases Fellowship Training Program at the Johns Hopkins School of Medicine, and a Professor in the Department of Medicine, Division of Infectious Diseases. Ray also holds appointments in Viral Oncology and the Division of Health Sciences Informatics. He is affiliated with the Institute for Computational Medicine at Johns Hopkins and is licensed to practice medicine in Maryland.
The transmission of hepadnaviruses between their natural hosts, humans, non-human primates, and birds, including intra-species host transmission and cross-species transmission, is a topic of study in virology.
RIG-I-like receptors are a type of intracellular pattern recognition receptor involved in the recognition of viruses by the innate immune system. RIG-I is the best characterized receptor within the RIG-I like receptor (RLR) family. Together with MDA5 and LGP2, this family of cytoplasmic pattern recognition receptors (PRRs) are sentinels for intracellular viral RNA that is a product of viral infection. The RLR receptors provide frontline defence against viral infections in most tissues.
Nonstructural protein 5A (NS5A) inhibitors are direct acting antiviral agents (DAAs) that target viral proteins, and their development was a culmination of increased understanding of the viral life cycle combined with advances in drug discovery technology. However, their mechanism of action is complex and not fully understood. NS5A inhibitors were the focus of much attention when they emerged as a part of the first curative treatment for hepatitis C virus (HCV) infections in 2014. Favorable characteristics have been introduced through varied structural changes, and structural similarities between NS5A inhibitors that are clinically approved are readily apparent. Despite the recent introduction of numerous new antiviral drugs, resistance is still a concern and these inhibitors are therefore always used in combination with other drugs.
Ground squirrel hepatitis virus, abbreviated GSHV, is a partially double-stranded DNA virus that is closely related to human Hepatitis B virus (HBV) and Woodchuck hepatitis virus (WHV). It is a member of the family of viruses Hepadnaviridae and the genus Orthohepadnavirus. Like the other members of its family, GSHV has high degree of species and tissue specificity. It was discovered in Beechey ground squirrels, Spermophilus beecheyi, but also infects Arctic ground squirrels, Spermophilus parryi. Commonalities between GSHV and HBV include morphology, DNA polymerase activity in genome repair, cross-reacting viral antigens, and the resulting persistent infection with viral antigen in the blood (antigenemia). As a result, GSHV is used as an experimental model for HBV.