Mechanism of inflammation-induced steroid resistance

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DESCRIPTION (provided by applicant): Although steroids are highly effective in the control of asthma, some patients fail to respond even to high doses. Steroid resistance is a veritable health challenge due to the absence of therapeutic alternatives and a financial burden as steroid-resistant patients account for more than 50% of asthma related healthcare costs. The candidate's current research at the University of Pennsylvania focuses in studying steroid resistance in airway smooth muscle (ASM), a tissue that is relevant for lung diseases. The short term goal of the studies performed currently and during the mentored phase of this award (K99) is to delineate the molecular mechanisms that underlay the diminished efficacy of steroids. This study will be pursued during the independent phase of this award (R00) with the ultimate objective to develop new therapeutic options to treat steroid-resistant asthmatics. The candidate's long term goal is to establish his own independent research program and submit an R01 application. The central hypothesis of this proposal is novel and states that pro-asthmatic cytokines impair steroid function in ASM cells through the coordinated activation of three pathways: (i) GR beta, a steroid receptor beta isoform that can act as an inhibitor of GC actions (will be addressed in Aim 1), (ii) IRF-1, a transcription factor that regulates many inflammatory genes (will be addressed in Aim 2), and (iii) Serine/threonine protein phosphatase 5 (PP5), shown to act as an inhibitor of steroid actions in different cell lines (will be addressed in Aim 3). All three Aims of the present proposal will rely on multiple complementary approaches such as siRNA technology, transfection of reporter vectors as well as over-expression of constitutively active or dominant negative proteins, co-immunoprecipitation and co-localization techniques, chromatin immunoprecipitation and gel shift assays. Subsequently, this award will dramatically enhance the candidate's technical skills and will broaden his expertise in molecular pharmacology and cell biology. We believe that our proposal is relevant to public health since improving the knowledge about the factors that lead to steroid resistance will help design new therapeutic agents or alternatives to treat steroid-resistant asthmatics.