An extended mini-complement factor H molecule ameliorates experimental C3 glomerulopathy.

Nichols, Eva-Maria; Barbour, Thomas D; Pappworth, Isabel Y; Wong, Edwin K S; Palmer, Jeremy M; Sheerin, Neil S; Pickering, Matthew C; Marchbank, Kevin J · Kidney Int · 2015

basic_science · Level V

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Abstract

Abnormal regulation of the complement alternative pathway is associated with C3 glomerulopathy. Complement factor H is the main plasma regulator of the alternative pathway and consists of 20 short consensus repeat (SCR) domains. Although recombinant full-length factor H represents a logical treatment for C3 glomerulopathy, its production has proved challenging. We and others have designed recombinant mini-factor H proteins in which 'non-essential' SCR domains have been removed. Here, we report the in vitro and in vivo effects of a mini-complement factor H protein, FH<sup>1-5^18-20</sup>, using the unique factor H-deficient (Cfh-/-) mouse model of C3 glomerulopathy. FH<sup>1-5^18-20</sup> is comprised of the key complement regulatory domains (SCRs 1-5) linked to the surface recognition domains (SCRs 18-20). Intraperitoneal injection of FH<sup>1-5^18-20</sup> in Cfh-/- mice reduced abnormal glomerular C3 deposition, similar to full-length factor H. Systemic effects on plasma alternative pathway control were comparatively modest, in association with a short half-life. Thus, FH<sup>1-5^18-20</sup> is a potential therapeutic agent for C3 glomerulopathy and other renal conditions with alternative pathway-mediated tissue injury.