Related Experiment Video
Updated: Oct 5, 2026

Differentiation of Functional Osteoclasts from Human Peripheral Blood CD14+ Monocytes
Published on: January 27, 2023
Hepatocyte growth factor (HGF), HGF activator, and c-Met in synovial tissues in rheumatoid arthritis and
M Nagashima1, J Hasegawa, K Kato
1Department of Joint Disease and Rheumatism, Nippon Medical School, Tokyo, Japan. Nagashima_Masakazu/rheum@nms.ac.jp
Objective:
Hepatocyte growth factor (HGF) is a multifunctional polypeptide that has been implicated in cancer growth, tissue development, and wound repair. Its actions are dependent on activation by HGF activator (HGFA) and its binding to a specific HGF receptor (c-Met). We examined the role of HGF, HGFA, and c-Met in synovial tissues in rheumatoid arthritis (RA) and osteoarthritis (OA), and their localization and mRNA expression.
Methods:
Immunohistochemical staining, Western blotting, RT-PCR, and in situ hybridization (ISH) for HGF, HGFA, and c-Met were performed on synovial tissue specimens from 10 patients with RA and 4 with OA, and 2 healthy controls.
Results:
Immunohistochemical staining revealed that HGFA and c-Met were strongly expressed in fibroblasts, macrophages, endothelial cells, and synovial lining cells. HGF was expressed only faintly in macrophages and fibroblasts, and not at all in the endothelial cells of RA and OA synovial tissue. HGFA was detected near 73 and 34 kDa on Western blot analysis, corresponding to inactive and active HGFA, respectively. RT-PCR showed HGF, HGFA, and c-Met mRNA in RA, OA, and control synovial tissue. ISH and immunohistochemistry revealed mRNA expression for HGF, HGFA, and c-Met in the cell types mentioned above.
Conclusion:
HGFA, HGF, and c-Met mRNA are expressed in synovial tissue in RA and OA, and HGF is activated by HGFA and binds to c-Met on endothelial cells, inducing angiogenesis.
Related Concept Videos
The JAK-STAT Signaling Pathway
T Cell Types and Functions
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
TGF - β Signaling Pathway
Role of Hematopoietic Growth Factors
Thrombopoietin (TPO), mainly released by the liver,...
Mitogens and the Cell Cycle
Liver Regeneration
Cells of Liver
The liver comprises four major types of cells— hepatocytes, stellate, Kupffer, and sinusoidal endothelial cells. The hepatocytes are large...