Dr. Biao He’s Lab
Director: Biao He, PhD
Our long-term goal is to understand viral pathogenesis at the molecular level, especially how viral proteins overcome host defense mechanisms at the molecular level in host.
At present, our laboratory studies how paramyxovirus parainfluenza virus 5 (PIV5, formerly known as simian virus 5, SV5) and mumps virus proteins inhibit apoptotic pathways. We have been focusing our research effort on interactions between PIV5 small hydrophobic protein (SH) as well as the V protein and host apoptotic pathways.
In addition to basic research, we have also been involved in translational research to explore using PIV5 as a vector for gene delivery as well as using apoptosis-inducing recombinant PIV5 as a possible agent for cancer therapy.
Research Interest: PIV5 & Host Interactions
PIV5 is a member of the Rubulavirus genus of the family Paramyxoviridae which includes many important human and animal pathogens such as mumps virus, human parainfluenza virus type 2 and type 4, Newcastle disease virus, Sendai virus, HPIV3, measles virus, canine distemper virus, rinderpest virus and respiratory syncytial virus. Although PIV5 was originally isolated from cultured primary monkey cells its natural host is the dog in which it causes kennel cough. PIV5 can infect humans and isolates have been obtained from human sources, but no known symptoms or diseases in humans have been associated with PIV5.
Unlike most paramyxoviruses, PIV5 can infect many cells with little cytopathic effect (CPE) and PIV5 infection does not induce apoptosis. For example, PIV5 can grow in MDBK cells productively up to 40 days without severe CPE. The ability of PIV5 to grow productively without inducing CPE suggests that PIV5 may have mechanisms to evade host defense responses such as apoptosis.
PIV5 encodes eight known viral proteins. Nucleocapsid protein (NP), phosphoprotein (P), V protein and large RNA polymerase (L) protein are important for transcription and replication of the viral RNA genome. The V protein causes degradation of signal transducer and activator of transcription (STAT) 1 protein, a key protein for interferon responses, in human cells and slows down cell cycle. The fusion (F) protein, a glycoprotein, mediates both cell-to-cell and virus-to-cell fusion in a pH-independent manner that is essential for virus entry into cells. The hemagglutinin-neuraminidase (HN), another viral glycoprotein, is also involved in virus entry and release from the host cells. The matrix (M) protein is thought to play an important role in virus assembly. Unlike most paramyxoviruses, PIV5 encodes a small hydrophobic (SH) integral membrane protein located between the genes for the glycoproteins F and HN. The SH protein is a 44-residue hydrophobic integral membrane protein and is oriented in membranes with its N terminus in the cytoplasm.
The SH gene was deleted from cDNA of the PIV5 genome and a viable virus was recovered using a reverse genetics system. The virus (rPIV5ΔSH) caused increased CPE and apoptosis in MDBK cells (bovine cell line), L929 cells (mouse cell line) and MDCK cells (canine cell line), but not in HeLa T4 and A549 cells (human cell lines).rPIV5ΔSH was indistinguishable from the wild type SV5 virus in single-step growth curve, plaque size, viral protein and viral mRNA synthesis. Co-infection of rPIV5ΔSH with PIV5 did not result in CPE, which lends support to the notion that expression of the SH protein is the key factor in preventing apoptosis.
Examination of rPIV5ΔSH in a small animal model system showed that it was attenuated in vivo as compared to wild-type rPIV5, even though it caused vastly greater CPE in mouse, bovine and canine cell types, a finding consistent with the notion of clearance of apoptotic cells in a host species.
PIV5 provides a good model system to understand how paramyxoviruses induce and inhibit apoptosis. Activation of apoptotic cascades can be studied using rPIV5ΔSH and inhibition of apoptosis can be studied using wild type PIV5 virus. Additional mutant PIV5 viruses that induce apoptosis in infected cells can be obtained by manipulating PIV5's RNA genome using a reverse genetics system and studied. Pathogenicity of mutant PIV5 viruses can be examined in vivo using a small animal model system.
Research Interest: Pathogenesis of Mumps Virus
Mumps virus causes acute infections in humans and about 10% of infection leads to aseptic meningitis. Although several mumps virus genome sequences are known, molecular bases of mumps virus pathogenesis are not clear.
Long-term goal of this work is to understand how virus overcomes host defense mechanisms, especially how viral proteins overcome host innate immunity at molecular levels in tissue culture cells as well as in animals. The small hydrophobic protein (SH) of PIV5, a virus closely related to mumps virus, plays an important role in inhibiting tumor necrosis factor (TNF)-alpha activated apoptotic pathway and the deletion of SH results in an attenuated virus in vivo.
We hypothesize that inhibition of apoptosis by virus-infected cells contributes to viral pathogenesis and mumps virus small hydrophobic protein (SH) plays essential roles in inhibition of cell death in virus-infected cells like SH of PIV5 even though both SH proteins have no sequence homologies.
To test these hypothesis, (1) a reverse genetics system in which infectious mumps virus from cDNA of a clinical isolate will be obtained will be established, (2) mumps virus lacking SH gene (rMuVƒ¢SH) will be generated and (3) compared with its parental mumps virus in tissue culture cells and in a rat model system.
Research Interest: Using PIV5 as a Vector for Vaccine Development
PIV5 is an excellent vector for expressing foreign genes and for live vaccine development. PIV5 does not have a DNA phase in its life cycle and it replicates solely in cytoplasm, therefore using PIV5 as a vector avoids possible unintended consequences from genetic modifications of host cell DNAs. The genome structure of PIV5 is stable and simple. Using the reverse genetics system for the PIV5, a recombinant PIV5 containing a hemaglutinin (HA) gene from influenza A virus (rPIV5-HA) was generated. In collaboration with Dr. Durbin at the Ohio State University, we found a single dose inoculation of the virus provided immunity to mice against influenza A virus infection.
Recombinant PIV5 viruses expressing other viral proteins such as gag protein of HIV have been generated. The virus grows normally as wild type PIV5. At present, the virus is being tested as a live vaccine in mice.
Research Interest: Testing PIV5 as an Oncolytic Agent
Many viruses have been successfully used as oncolytic agent for treating various cancers in animal model systems and some of them are in clinical trails.
PIV5 viruses with mutation in SH or V proteins induce apoptosis in many cell types including tumor cell lines such as HeLa and A549, a human lung carcinoma cell line, whereas wild type PIV5 causes little CPE in the cells. In preliminary studies, mutant PIV5 viruses killed human metastatic breast cancer cell line MDA-MB- 231 and MDA-MB-435.
It is known that cancer cells are often defective in anti-viral pathways and are susceptible to virus infection, whereas normal cells are capable of anti-viral responses and thus immune from killing by oncolytic viruses. We have started to test whether PIV5 mutants can selectively kill invasive breast cancers developed from the MDA-MB-231 and MDA-MB-435 cells in a nude mouse model system.
HE'S LAB: Current Lab Members
Biao He, Ph.D., Principal Investigator
Zhenhai Chen, Ph.D., Postdoctoral Fellow
Stephanie Foster , B.S., Reasearch Technician
Gwen Hirsch, M.S., Reasearch Technician
Zhuo Li, Ph.D., Postdoctoral Fellow
Yuan Lin, M.S., Research Assistant Scientist
Mai Nguyen, Undergraduate Student
Shannon Phan, B.S., Graduate Student
Adrian Pickar, B.S., Graduate Student
Ryan Place, Undergraduate Student
Pei Xu, B.S., Graduate Student
Yang Yang, B.S., Graduate Student
HE'S LAB: Former Lab Members
Terri Rothermel, B.S., Graduate Student
Angela Bright, M.S., 2003
Laurie Shuman, B.S., Graduate Student
Frank Horvath, B.S., Graduate Student
Elizabeth Cohen, B.S., 2005
Nikki Ford, B.S., 2005
Chris Murphy, B.S., 2005
Jason Aligo, M.S., 2005
Rebecca Wilson, B.S., Lab Technician
Erica Taddeo, B.S. 2006
Mercedes Stoneberg, B.S. 2006
Ping Wang, B.S., Graduate Student
Mahipal Suraneni, Ph.D., Postdoctoral Fellow
Celia Keim, B.S., 2007
Khalid A. Timani, Ph.D., Postdoctoral Fellow
Minghao Sun, Ph.D., 2007
Jie Xu, M.S., Project Associate, 2005-9
Ying-Hsien Huang, B.S., 2009
Jui Patel, B.S., Technician, 2007-9
Leyi Wang, Ph.D., Postodctoral Fellow, 2009-10
Matthew Wolfgan, B.S., Technician, 2007-10
Sandra Fuentes, Ph.D., 2010; Postdoctoral Fellow 2010-2011
Denyun Sun, Ph.D., 2011
Priya Luthra, Ph.D., 2011; Postdoctoral Fellow 2011
Stella Yoon, Undergraduate Student
Alex D'Andrea, B.S. 2012