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TNF-alpha blockade by nonviral gene therapy in collagen-induced arthritis
Arthritis Res Thervolume 5, Article number: 130 (2003)
Gene therapy using electrotransfer (ET) is a safe method for transferring therapeutic transgenes in vivo. We have used this method to administer transgenes encoding three human tumour necrosis factor alpha soluble receptor I (hTNFRIs) variants engineered in Scherman's research unit. The ET parameters and therapeutic effects in collagen-induced arthritis (CIA) in mice were studied.
The following three plasmids were used: pCOR(hTNFRIs)1, pCORhTNFRIs/mIgG1, and pCOR(hTNFRIs)2. These encode, respectively, the monomeric (hTNFRIs)1 form, the chimeric hTNFRIs/mIgG1form or the dimeric (hTNFRIs)2 form of hTNFRIs. They were electro-transferred in the tibial cranial muscle. The hTNFRIs concentrations were determined by ELISA. Biological activity (tumour necrosis factor alpha neutralization) of the fusion protein encoded by each of the plasmids was determined using L929 cells. Detection of the plasmid genome was determined by PCR. CIA was induced in DBA/1 mice with bovine type II collagen in complete Freund adjuvant.
ET of the three plasmids allowed dose-dependent hTNFRIs production in sera and muscle after 10 days. Local expression in the muscle lasted for at least 6 months. Systemic expression in the serum lasted for at least 6 months for the hTNFRIs/mIgG1 form, while it was shorter for the two other forms (about 3 weeks). After intramuscular ET of any of the three plasmids, muscle lysates were able to inhibit tumour necrosis factor alpha cytotoxicity on L929 cells ex vivo. No plasmid DNA was found in the organs distant from the injected muscle (liver, spleen, kidney, gonads, heart, lung, brain and distant muscle). ET of 50 μg pCOR/sTNFRI/IgG1plasmid at the onset of clinical disease induced a clear-cut decrease of clinical and histological signs of arthritis. The dimeric (hTNFRIs)2 form was also efficient, although the effect was weaker than with the fusion protein. The monomeric form had no effect on arthritides.
Intramuscular ET of plasmids encoding the three forms of hTNFRIs (monomeric, dimeric and the IgG chimera) leads to a production of biologically active protein and, most importantly, is followed by a long-term secretion of hTNFRIs in the serum. CIA is efficiently inhibited when ET of plasmids encoding either the chimera or the dimeric form of the hTNFRIs was performed at the onset of the clinical signs.