Endogenous regulation of a therapeutic transgene restores homeostasis in arthritic joints

Abstract

The treatment of chronic inflammatory diseases is complicated by their unpredictable, relapsing clinical course. Here, we describe a new strategy in which an inflammation-regulated therapeutic transgene is introduced into the joints to prevent recurrence of arthritis. To this end, we designed a recombinant adenoviral vector containing a two-component, inflammation-inducible promoter controlling the expression of human IL-10 (hIL-10) cDNA. When tested in vitro, this system had a low-level basal activity and was activated four to five orders of magnitude by various inflammatory stimuli, including TNF-α, IL-1β, IL-6, and LPS. When introduced in joints of rats with recurrent streptococcal cell wall–induced arthritis, the IL-10 transgene was induced in parallel with disease recurrence and effectively prevented the influx of inflammatory cells and the associated swelling of the joints. Levels of inflammation-inducible hIL-10 protein within the joints correlated closely with the severity of recurrence. An endogenously regulated therapeutic transgene can thus establish negative feedback and restore homeostasis in vivo while minimizing host exposure to the recombinant drug

Application of a disease-regulated promoter is a safer mode of local IL-4 gene therapy for arthritis

“…This however, has not been investigated so far; similar studies focused rather on effective transgene expression under arthritic conditions. 12,[28][29][30] In this study, we demonstrate for the first time that disease-regulated mIL-4 expression by the IL-1E/IL-6P promoter provides not only therapeutically efficacious protein levels under arthritic conditions, but also sufficiently low activity under naive conditions. Minimizing the undesired effects of biologicals, in this case the potent proinflammatory and chemotactic properties of IL-4, requires promoters with low basal activity under naive conditions.…”

An inflammation-inducible adenoviral expression system for local treatment of the arthritic joint

“…17,18 We compared the expression characteristics of this two-component system with the IL-1/IL-6 hybrid promoter construct. The C3-Tat/Hiv twocomponent system in RAW cells showed the same high background activity and LPS induction comparable to the conventional CMV promoter ( Figure 7).…”

“…It must be emphasized that the basal transgene levels and the fold induction using the C3-Tat/HIV two-component system were far better in adenoviral-transfected HepG2 cells and in primary rat synovial fibroblasts. 16,18 A major difference was the 24-h serum (0.5% FBS) starvation used in these studies whereas we performed our experiments A disease-inducible promoter responsive in arthritis FAJ van de Loo et al in 5% FCS. Different batches of fetal calf serum may contain varying amounts of growth factors, cytokines (IL-6) or traces of endotoxin, and the C3-Tat/HIV twocomponent promoter system is extremely responsive to stimulation.…”

“…The feasibility of this two-component system as an inflammation-inducible promoter for autoregulated expression of IL-10 and IL-1Ra was recently demonstrated in two different experimental arthritis models. 17,18 However, this promoter may not be suitable for RA as the Tat is a foreign immunogenic protein and may have undesirable effects by transactivating host genes, and Tat immunogenicity has been implicated in CNS disorder AIDS dementia due to its toxicity. For this we constructed a hybrid promoter of the enhancer region of the human IL-1 promoter with the human IL-6 promoter, which does not possess the gene-silencing CpG regions that are present in most viral promoters (eg CMV promoters).…”

Vectors for the treatment of autoimmune disease

“…In both studies, a single adenoviral vector was designed which encoded either hIL-1Ra 174 or hIL-10. 175 In mouse CIA Ad (10 7 PFU) harbouring the construct C3-Tat/HIV-hIL-1Ra were injected i.a. followed by disease induction 3 days later.…”