Complement C5a and C5a receptor 1 mediates glomerular damage in focal segmental glomerulosclerosis

Area of Science:

• Nephrology
• Immunology
• Complement System Biology

Background:

• Complement activation is implicated in focal segmental glomerulosclerosis (FSGS) progression.
• Mechanisms of complement-induced podocyte injury and parietal epithelial cell (PEC) activation in FSGS remain unclear.

Purpose of the Study:

• To investigate the role of the C5a-C5aR1 axis in FSGS pathogenesis.
• To evaluate the therapeutic potential of a C5aR1 antagonist in FSGS.

Main Methods:

• Assessed glomerular C5aR1 expression in FSGS patients.
• Utilized an Adriamycin-induced nephropathy mouse model.
• Examined effects of C5aR1 antagonist on PECs and podocytes in vitro and in vivo.

Main Results:

• C5aR1 was overexpressed in FSGS kidneys, correlating with disease severity and prognosis.
• C5aR1 antagonist treatment attenuated proteinuria, kidney damage, and glomerulosclerosis in mice.
• Antagonist reduced PEC activation/proliferation, mitigated podocyte loss, and decreased complement deposition.
• In vitro studies showed C5aR1 antagonist reversed FSGS plasma-induced podocyte injury and modulated PEC responses.

Conclusions:

• The C5a-C5aR1 axis on podocytes and PECs is pathogenic in FSGS.
• C5aR1 antagonism offers a potential therapeutic strategy for FSGS.