Endogenous regulation of a therapeutic transgene restores homeostasis in arthritic joints
A.V. Miagkov, … , R.S. Munford, S.S. Makarov
A.V. Miagkov, … , R.S. Munford, S.S. Makarov
Published May 1, 2002
Citation Information: J Clin Invest. 2002;109(9):1223-1229. https://doi.org/10.1172/JCI14536.
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Article Genetics

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.

Authors

A.V. Miagkov, A.W. Varley, R.S. Munford, S.S. Makarov

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Figure 5

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The expression of inducible hIL-10 transgene in vivo. (a) Reactivated vs...
The expression of inducible hIL-10 transgene in vivo. (a) Reactivated vs. unreactivated joints. Animals with PG-APS–preinjured ankle joints received IA Ad.C3-tat/HIV–hIL-10 on day –2. Arthritis was reactivated in half the animals by intravenous PG-APS (black bars) on day 0. The other half was sham-injected with saline (white bars). The concentrations of hIL-10 in joint perfusates were assessed by ELISA. Each bar shows the mean ± SEM of four joints. In the unreactivated group, hIL-10 concentrations were at or below the limit of detection (1 ng/ml). In a control group (Ad.C3-tat/HIV-luc injected animals), the expression of luciferase has reached a peak at day 4 after reactivation (data not shown). (b) Constitutive vs. inducible transgene expression. In a similar experiment, animals were IAinjected at day –2 with the constitutive Ad.CMV-hIL-10 or inducible Ad.C3-tat/HIV–hIL-10. Following reactivation of arthritis (day 0), hIL-10 levels in joint lavages were assessed by Western blotting. Ad.RR5: perfusates of joints injected with an empty Ad. Each lane represents a pool of four joints. In a parallel control experiment, animals were IAinjected with Ad.C3-tat/HIV-luc reporter, which expression persisted through day 4 (data represented by Figure 2c). (c) Levels of inflammation-induced hIL-10 correlate with the severity of arthritis. Each point represents data from an independent experiment and is the average of four or more joints (see Table 1); error bars equal ± SEM. Abscissa: maximal SCW-induced swelling in the counterpart control animals (injected with empty or with reporter Ad). Ordinate: maximal average hIL-10 induction [hIL-10 (reactivated joints)/hIL-10 (unreactivated joints)] in Ad.C3-tat/HIV–hIL-10 injected animals.