382 The Role of the IL-6-IGF-II Axis in Systemic Sclerosis-Associated Lung Fibrosis

Abstract

OBJECTIVES/GOALS: Interleukin (IL)-6 is produced in excess in Systemic Sclerosis (SSc). Likewise, microarray analysis of Insulin-like Growth Factor (IGF)-II-treated NL fibroblasts revealed increased expression of the basic helix-loop-helix transcription factor, BHLHB2. Our goal is to delineate the role of BHLHB2 in the fibrotic response to IGF-II and IL-6. METHODS/STUDY POPULATION: Primary lung fibroblasts were cultured from human lung tissues at 37oC and 5% CO2. Cell cultures were stimulated with IL-6. Gene expression was measured using quantitative PCR (qPCR). IGF-II mRNA expression levels after IL-6 stimulation were compared with those of the housekeeping gene PPIB (Peptidylprolyl Isomerase B). Western blot was performed on nuclear and chromatin-bound subcellular fractions from treated lung fibroblasts. BHLHB2 protein levels were assayed in response to IGF-II in comparison to PBS as vehicle control. RESULTS/ANTICIPATED RESULTS: Results: Our results show that IL-6 increases IGF-II levels in fibroblasts. In turn, IGF-II increases BHLHB2 nuclear localization. We further show that IL-6 increases BHLHB2 levels and its nuclear localization in lung fibroblasts. Our findings are novel since the role of the transcription factor BHLHB2 in the IL-6 induced/ IGF-II-mediated fibrotic response in SSc lung disease remains unexplored. DISCUSSION/SIGNIFICANCE: Our findings may provide a rationale for combination therapy to block IL-6 and IGF-II function concomitantly and thus halt the progression of SSc pulmonary fibrosis (PF). Our findings may have wide implications for lung fibrosis associated with various diseases, since SSc-PF, is characterized by the activation of common fibrotic pathways.