Visit the Bouchard Laboratory.

Liver cancer is one of the most common cancers worldwide. While the exact molecular mechanisms that are associated with the development of liver cancer are not entirely understood, potential causes include exposure to environmental toxins and drugs, alcohol consumption, and chronic infections of the liver with viruses such as the hepatitis B virus (HBV). The work in my laboratory focuses on studying processes involved in hepatocyte transformation; hepatocytes are the major epithelial cell of the liver. Our main interest is to understand the causes of HBV-associated liver cancer. Approximately 80% of liver cancers can be attributed to chronic infections with HBV. Precisely how HBV causes liver cancer is unknown but is thought to involve the consequences of immune-mediated destruction of HBV-infected hepatocytes, and resultant liver regeneration, as well as activities of HBV proteins such as the HBV X protein (HBx).

HBx is a multifunctional protein that regulates HBV replication and influences cellular transcription, proliferation, and apoptotic and signal transduction pathways. However, the exact means by which HBx influences such diverse processes is not understood. We demonstrated that one HBx activity is modulation of cellular cytosolic calcium levels, which results in the activation of Pyk2 and Src kinases and regulation of apoptotic and cell proliferation pathways. Alterations in calcium signaling have numerous consequences for cellular metabolism and may explain many of the diverse functions that have been attributed to HBx and its putative role in the development of HBV-associated liver cancer. We recently demonstrated that HBx modulation of calcium signaling is through regulation of the mitochondrial permeability transition pore (MPTP). We are continuing to study HBx-induced calcium signaling as well as other activities associated with HBx expression to determine the precise mechanism through which this protein influences such a diverse array of cellular pathways. These studies are performed in established human liver cell lines, in cultured primary rat hepatocytes, and in vivo through the use of adenovirus recombinants that can transduce HBV into the livers of mice. Such studies should help delineate how this protein and chronic HBV infections can lead to transformation of liver cells and the development of liver cancer.

We are also exploring how alcohol exposure and HBV infections can synergize to enhance the development of liver cancer. There is evidence that chronic HBV infections combined with chronic alcohol consumption dramatically increases progression to the development of liver cancer, but precisely how this occurs is unknown. We are using a model system of cultured primary rat hepatocytes that are infected with HBV and exposed to alcohol to define cellular signaling pathways that are impacted by the combination of these stimuli and evaluating the consequence for hepatocyte physiology.

We are also exploring how the gut microbiome and the liver cross-communicate in a mouse model of fatty liver disease. We are exploring how a high-fat diet affects various signaling pathways in the liver and how this is linked to changes in the gut microbiome. Our goal is to determine how cross-communication between the gut microbiome and the liver can impact the development of fatty liver disease, a major global cause of morbidity and mortality. We aim to understand how cross-communication between the microbiome and liver could be manipulated to decrease or counter the development of fatty liver disease in obese individuals.

Finally, we are also developing alternative liver models that can be used to study the consequence of viral infections and/or drug, toxin or alcohol exposure for liver physiology. In collaboration with Dr. Moses Noh, an engineer at Drexel University, we are using recent advances in microfabrication and microfluidic technologies to develop a miniaturized human liver model system. This system uses small numbers of primary liver cells that are maintained in layered co-cultures in microfabricated microchannels. This type of system facilitates the long-term maintenance of liver cells, mimics the microenvironment of the liver, and can be used to study various aspects of liver physiology. We have successfully generated layered co-cultures of primary rat hepatocytes and liver sinusoid endothelial cells and are now expanding to studies with primary human liver cells. An advantage of this novel liver model system is that it requires very small numbers of cells while still generating a system that simulates a basic functional unit of the liver. Our long-term goal is to use this system to study the response of human liver cells to various stimuli such as an HBV infection and/or alcohol and drug exposure.

Commonwealth of Pennsylvania Announces Recent CURE Grant Recipients
(August 14, 2023)

Drexel Community Learns Mental Health Awareness and Response
(June 22, 2021)

2017 CURE Grant Awardees
(March 20, 2017)

"New Frontiers in Liver Health: Targeting Obesity"
College of Medicine Alumni Magazine (Fall/Winter 2016)

Selected Publications (See all Michael Bouchard's publications in PubMed.)

"A broad investigation of the HBV-mediated changes to primary hepatocyte physiology reveals HBV significantly alters metabolic pathways"
J Lamontagne, JC Casciano, and M Bouchard
Metabolism, Epub ahead of print. PMID:  29410347 (2018)

"The hepatitis B virus HBx proteins elevates cytosolic and mitochondria calcium in cultured human hepatocytes"
JC Casciano and M Bouchard
Virus Research 246: 23-27. PMID:  29307794 (2018)

"Human Liver Sinusoid on a Chip for Hepatitis B Viral Replication Study"
YB Kang, S Rawat, N Duchemin, M Bouchard, and M Noh
Micromachines, 8, 27 (2017)

"Hepatitis B virus modulates store-operated calcium entry to enhance viral replication in primary hepatocytes"
JC Casciano, N Duchemin, RJ Lamontagne, LF Steel, and M Bouchard
PLoSOne, 12(2) PMID:  28151934 (2017)

"Intrinsic hepatocyte dedifferentiation is accompanied by upregulation of mesenchymal markers, protein sialylation and core alpha 1,6 linked fucosylation"
A Mehta, MA Comunale, S Rawat, JC Casciano, J Lamontagne, H Herrera, A Ramanathan, L Betesh, M Wang, P Norton, LF Steel, and M Bouchard
Sci Rep., 6:27965 PMID: 27328854 (2016)

"The Hepatitis B Virus HBx protein activates AKT to simultaneously regulate HBV replication and hepatocyte survival"
S Rawat and M Bouchard
J. Virol.89(2):999-1012 (2015)

"Technical standards for hepatitis B virus X protein(HBx) research"
B Slagle, O Andrisani, M Bouchard, C Lee, J Ou, A Siddiqui
Hepatology, Epub Aug 7 (2014)

"Cell cycle regulation during viral infection"
S Bagga and M Bouchard (2014)
Methods Mol Biol. 1170:165-227 (2014)

"Protein phosphatase 2A (PP2A) regulates low density lipoprotein uptake through regulating sterol response element-binding protein-2 (SREBP-2) DNA binding"
Rice L, M Donigan, M Yang, W Liu, D Pandya, BK Joseph, V Sodi, TL Gearhart, J Yip, M Bouchard, JT Nickels Jr.
J.Biol Chem. 289(24):17268-79 (2014)

"Layered long-term co-culture of hepatocytes and endothelial cells on a transwell membrane: toward engineering the liver sinusoid"
Kang YB, Rawat S, Cirillo J, Bouchard M, Noh HM.
Biofabrication, Dec. 2013; 5(4):045008. doi: 10.1088/1758-5082/5/4/045008. (Epub Nov 26, 2013)

"Modulation of apoptotic signaling by the hepatitis B virus X protein"
Rawat S, A. Clippinger, M. Bouchard
Viruses 8: 2945-72 (2012)

"The hepatitis B virus X protein elevates cytosolic calcium signals by modulating mitochondrial calcium uptake"
B. Yang and M. Bouchard
J Virol. 86: 313-327 (2012)

"The C-terminal region of the hepatitis B virus X protein is essential for its stability and function"
R Lizzano, B Yang, A Clippinger and M Bouchard
Virus Res.155: 231-239 (2011)

"The hepatitis B virus HBx protein modulates cell cycle regulatory proteins in cultured primary human hepatocytes"
T Gearhart and M Bouchard
Virus Res. 155: 363-367 (2011)

"Hepatitis B and C virus hepatocarcinogenesis: lessons learned and future challenges"
M Bouchard and S Navas-Martin
Cancer Letters 305: 123-43 (2011)

"Replication of the hepatitis B virus requires a calcium-dependent HBx-Induced G1 phase arrest of hepatocytes"
T Gearhart and M Bouchard
Virology, 407: 14-25 (2010)

"The hepatitis B virus X protein modulates hepatocyte proliferation pathways to stimulate viral replication"
T Gearhart and M Bouchard
Journal of Virology, 84: 2675-2686 (2010)

"In situ intracellular spectroscopy with surface enhanced raman spectroscopy (SERS)-enabled nanopipettes"
EA Vitol, Z Orynbayeva, M Bouchard, J Azizkhan-Clifford, G Friedman, and Y Gogotsi
ACS Nano, 3; 3529-3536 (2009)

"The hepatitis B virus X protein modulates apoptosis in primary rat hepatocytes by regulating both NF-kB and the mitochondrial permeability transition pore"
A Clippinger, T Gearhart, and M Bouchard
Journal of Virology, 83: 4718-4713 (2009)

"Hepatitis B virus HBx protein localizes to mitochondria in primary rat hepatocytes and modulates mitochondrial membrane potential"
A Clippinger and M Bouchard
Journal of Virology, 82: 6798-6811 (2008)

"Microfluidic platform for hepatitis B viral replication study"
T Sodunke, M Bouchard, and H Noh
Biomed Microdevices, 10: 393-402 (2008)