DDR2 receptor promotes MMP-2-mediated proliferation and invasion by hepatic stellate cells

Area of Science:

• Cell Biology
• Biochemistry
• Hepatology

Background:

• Type I collagen is known to activate hepatic stellate cells (HSCs) during liver injury, but the underlying mechanisms remain unclear.
• Hepatic stellate cells play a critical role in liver fibrosis and injury response.

Purpose of the Study:

• To investigate the role of discoidin domain tyrosine kinase receptor 2 (DDR2) in type I collagen-mediated HSC activation.
• To elucidate the signaling pathways involved in DDR2-induced HSC proliferation and invasion.

Main Methods:

• Assessed DDR2 mRNA and protein expression in activated and quiescent HSCs in vitro and in vivo.
• Utilized stably transfected HSC lines overexpressing wild-type, constitutively active, truncated, or kinase-dead DDR2.
• Measured cell proliferation, invasion through Matrigel, and matrix metalloproteinase-2 (MMP-2) activity.

Main Results:

• DDR2 expression and tyrosine phosphorylation are induced in activated HSCs in response to type I collagen.
• Overexpression of DDR2 in HSCs enhanced proliferation and invasion, correlating with increased active MMP-2 levels.
• Type I collagen-induced DDR2 upregulation creates a positive feedback loop, further stimulating HSC activity.

Conclusions:

• DDR2 is a key mediator of type I collagen signaling in HSC activation during liver injury.
• Phosphorylated DDR2 promotes HSC proliferation and invasion by regulating MMP-2.
• Targeting the DDR2 pathway may offer therapeutic strategies for liver fibrosis.