Complement Factor H related protein 1 and immune inflammatory disorders.

Area of Science:

• Immunology
• Complement System Biology

Background:

• Human complement Factor H-related protein 1 (FHR-1) is a key regulator in innate immunity.
• FHR-1 exhibits paradoxical functions, promoting complement activation by binding C3b and restraining it by inhibiting C5 convertase.

Purpose of the Study:

• To summarize recent advancements in understanding FHR-1's role in innate immunity.
• To dissect FHR-1's function in various immune inflammatory disorders and disease pathogenesis.

Main Methods:

• Review of existing literature on FHR-1 function and associated diseases.
• Analysis of FHR-1's dual roles in complement activation and inflammatory processes.
• Examination of the impact of CFHR1 variations on immune inflammatory disorders.

Main Results:

• FHR-1's dual role in complement activation: promoting via C3b binding and restraining via C5 convertase inhibition.
• FHR-1 influences inflammatory cytokine release from monocytes, with deficiency exacerbating secretion.
• CFHR1 variations, particularly mutations in FHR-1's C-terminus and N-terminus, are associated with atypical haemolytic uraemia syndrome (aHUS) and C3 glomerulopathy (C3G), respectively.

Conclusions:

• The context-dependent functions of FHR-1 contribute to its complex role in innate immunity.
• Dysregulation of FHR-1 due to CFHR1 variations is implicated in diverse immune inflammatory disorders.
• Understanding FHR-1's distinct functions is crucial for comprehending and addressing associated disease pathogenesis.