Hepatic stellate cells (HSC) play a crucial role during liver fibrogenesis. Phagocytosis of apoptotic bodies from hepatocytes induces HSC activation with upregulation of procollagen alpha 1(I) and TGF-2 expression. In addition, recent data indicate that HSC behave as antigen presenting cells (APC). However, their role in the regulation of hepatic immune responses during fibrogenesis is not well understood. Galectin-3 (Gal3), a member of 2-galactoside-binding lectin family is known to regulate cell phagocytosis and also is an important immune regulator. According to our preliminary data Gal3 is an important mediator of liver fibrosis as Gal3 deficient HSC displayed decreased phagocytic activity and diminished profibrogenic activity and Gal3-/- mice developed decreased fibrosis. Therefore, our hypothesis is that Gal3 plays a role in liver fibrosis by regulating HSC phagocytosis and antigen presentation, and the subsequent immune responses. To test this hypothesis, our specific aims are 1) to study the mechanisms by which Gal3 regulates phagocytosis, 2) the role of Gal3 in the regulation of immune responses during liver fibrosis, and 3) the in vivo effects of Gal3 on profibrogenesis and immunoregulation will be studied. In addition, we will use the Gal3 inhibitor modified citrus pectin (MCP) in the in vivo fibrosis model to assess its antifibrogenic activity. These studies may lead to the development of new therapeutic modalities aimed at reversing or preventing liver fibrosis.

Public Health Relevance

Hepatic stellate cells produce extra collagen upon phagocytosing injured hepatocytes which leads to fibrosis and cirrhosis, and act as antigen presenting cells participating hepatic immune regulation. In the current study, we propose that galectin-3, an important immune regulator, plays a role in live fibrosis by mediating stellate cell phagocytosis and the subsequent immune reactions. The findings obtained from this project may lead to the development of new therapeutic strategies in the future.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Scientist Development Award - Research & Training (K01)
Project #
5K01DK090121-03
Application #
8623129
Study Section
Diabetes, Endocrinology and Metabolic Diseases B Subcommittee (DDK)
Program Officer
Podskalny, Judith M,
Project Start
2012-03-01
Project End
2017-02-28
Budget Start
2014-03-01
Budget End
2015-02-28
Support Year
3
Fiscal Year
2014
Total Cost
$97,239
Indirect Cost
$7,203
Name
University of California Davis
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
047120084
City
Davis
State
CA
Country
United States
Zip Code
95618
Tian, Jijing; Yang, Guoxiang; Chen, Huan-Yuan et al. (2016) Galectin-3 regulates inflammasome activation in cholestatic liver injury. FASEB J 30:4202-4213
Serizawa, Nobuko; Tian, Jijing; Fukada, Hiroo et al. (2015) Galectin 3 regulates HCC cell invasion by RhoA and MLCK activation. Lab Invest 95:1145-56
Bettaieb, Ahmed; Jiang, Joy X; Sasaki, Yu et al. (2015) Hepatocyte Nicotinamide Adenine Dinucleotide Phosphate Reduced Oxidase 4 Regulates Stress Signaling, Fibrosis, and Insulin Sensitivity During Development of Steatohepatitis in Mice. Gastroenterology 149:468-80.e10
Tian, Jijing; Feng, Yu; Fu, Hualing et al. (2015) The Aryl Hydrocarbon Receptor: A Key Bridging Molecule of External and Internal Chemical Signals. Environ Sci Technol 49:9518-31
Jiang, Joy X; Török, Natalie J (2014) NADPH Oxidases in Chronic Liver Diseases. Adv Hepatol 2014:
Jiang, Joy X; Török, Natalie J (2014) MLK3 as a regulator of disease progression in Non-alcoholic steatohepatitis. Liver Int 34:1131-2
Jiang, Joy X; Török, Natalie J (2013) Liver Injury and the Activation of the Hepatic Myofibroblasts. Curr Pathobiol Rep 1:215-223
Jiang, Joy X; Chen, Xiangling; Hsu, Daniel K et al. (2012) Galectin-3 modulates phagocytosis-induced stellate cell activation and liver fibrosis in vivo. Am J Physiol Gastrointest Liver Physiol 302:G439-46