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Production of biologically active complement factor H in therapeutically useful quantities.

Abstract

Human complement factor H (FH), an abundant 155-kDa plasma glycoprotein with 40 disulphide bonds, regulates the alternative-pathway complement cascade. Mutations and single nucleotide polymorphisms in the FH gene predispose to development of age-related macular degeneration, atypical haemolytic uraemic syndrome and dense deposit disease. Supplementation with FH variants protective against disease is an enticing therapeutic prospect. Current sources of therapeutic FH are restricted to human blood plasma highlighting a need for recombinant material. Previously FH expression in cultured plant, mammalian or insect cells yielded protein amounts inadequate for full characterisation, and orders of magnitude below therapeutic usefulness. Here, the V62,Y402 variant of FH has been produced recombinantly (rFH) in Pichia pastoris cells. Codon-optimisation proved essential whilst exploitation of the yeast mating α-factor peptide ensured secretion. We thereby produced multiple 10s-of-milligram of rFH. Following endoglycosidase H digestion of N-linked glycans, rFH (with eight residual N-acetylglucosamine moieties) was purified on heparin-affinity resin and anion-exchange chromatography. Full-length rFH was verified by mass spectrometry and Western blot using monoclonal antibodies to the C-terminus. Recombinant FH is a single non-aggregated species (by dynamic light scattering) and fully functional in biochemical and biological assays. An additional version of rFH was produced in which eight N-glycosylation sequons were ablated by Asn-Gln substitutions resulting in a glycan-devoid product. Successful production of rFH in this potentially very highly expressing system makes production of therapeutically useful quantities economically viable. Furthermore, ease of genetic manipulation in P. pastoris would allow production of engineered FH versions with enhanced pharmacokinetic and pharmacodynamic properties.

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  • Authors+Show Affiliations

    ,

    School of Chemistry and School of Biological Sciences, The University of Edinburgh, Edinburgh, UK. cschmidt@staffmail.ed.ac.uk

    , ,

    Source

    Protein expression and purification 76:2 2011 Apr pg 254-63

    MeSH

    Animals
    Blotting, Western
    Complement C3b
    Complement Factor H
    Electrophoresis, Polyacrylamide Gel
    Erythrocytes
    Genes, Synthetic
    Hemolysis
    Humans
    Light
    Macular Degeneration
    Mass Spectrometry
    Pichia
    Polymorphism, Single Nucleotide
    Recombinant Proteins
    Scattering, Radiation
    Sheep
    Surface Plasmon Resonance

    Pub Type(s)

    Journal Article
    Research Support, Non-U.S. Gov't

    Language

    eng

    PubMed ID

    21146613