Gene Therapy for Rheumatoid Arthritis

Résumé du livre

Rheumatoid arthritis (RA) is a chronic autoimmune disease manifesting primarily as an inflammatory, polyarthritis of the synovial joints. While biologic therapies such as anti-TNF-alpha have revolutionised the treatment of RA, such therapies result in systemic immunosuppression. Gene therapy has the potential to deliver therapeutic nucleic acids specifically to sites of rheumatological pathology, either through the transfection or transduction of joint-trafficking cells or via transcriptional targeting. Immunoglobulin binding protein (BiP) is a 78kD endoplasmic reticulum (ER) stress protein that has previously demonstrated immunomodulatory activity. BiP normally resides in the ER and has multiple roles including chaperoning nascent polypeptides and regulating the ER stress response. At times of stress, BiP may leave the cell and exert potent anti-inflammatory effects on myeloid lineage cells. When administered to mice with collagen-induced arthritis (CIA), recombinant human BiP (rhuBiP) protein can prevent arthritis when administered prophylactically and treat ongoing arthritis when administered therapeutically. A clone of the murine (m) BiP gene was modified to introduce 9 in-frame silent mutations to allow discrimination between endogenous and vector derived mBiP transcripts and to remove the 3' KDEL ER localisation signal, facilitating mBiP secretion. The mutant mBiP gene was subcloned into plasmid mammalian expression vectors and protein purified from permanently transfected 293T cells. mBiP produced in a mammalian expression system demonstrates similar biological activity to rhuBiP in vitro. Both proteins induce 1L-6, IL-10 and TNF-cc secretion from human peripheral blood mononuclear cells and IL-6, TNF-ct and IFN-y from naive DBA/1 splenocytes after 24 hours of stimulation. Intranasal gene delivery using plasmid DNA mammalian expression vectors was unsuccessful.