Mmp23b promotes liver development and hepatocyte proliferation through the tumor necrosis factor pathway in zebrafish

Area of Science:

• Developmental Biology
• Molecular Biology
• Biochemistry

Background:

• Matrix metalloproteinases (MMPs) regulate extracellular matrix (ECM) homeostasis and are implicated in physiological and pathological processes.
• MMPs are involved in processing cytokines and growth factors, influencing cellular signaling pathways.
• Liver development is a complex process involving precise regulation of cell proliferation and signaling.

Purpose of the Study:

• To investigate the role of mmp23b in zebrafish liver development.
• To elucidate the molecular mechanisms by which mmp23b influences liver growth.
• To explore the relationship between mmp23b and tumor necrosis factor (TNF) signaling in liver development.

Main Methods:

• Utilized enhancer trap transgenic zebrafish to identify liver-specific genes.
• Employed morpholino knockdown to assess the function of mmp23b in vivo.
• Investigated genetic interactions with TNF signaling components (tnfa, tnfb) in zebrafish.
• Performed biochemical assays using cell culture to study MMP23B-TNF interactions.

Main Results:

• mmp23b exhibits liver-specific expression in zebrafish.
• Knockdown of mmp23b leads to reduced liver size due to defective hepatocyte proliferation.
• mmp23b functions via the TNF signaling pathway; TNFalpha/beta modulation affects liver size, and TNFalpha/beta can rescue mmp23b knockdown phenotypes.
• Biochemical analysis shows human MMP23B directly interacts with TNF and mediates its release.

Conclusions:

• mmp23b plays a critical role in zebrafish liver development by regulating hepatocyte proliferation.
• The study establishes a functional link between mmp23b and TNF signaling in liver growth.
• The conserved nature of mmp23b/MMP23B suggests potential relevance in mammalian liver development and disease.