Project description:Pulmonary hypertension (PH) and cancer pathophysiology share common signal transduction pathways leading to abnormal endothelial and smooth muscle cell interactions and angioproliferative vasculopathy. Sorafenib (Sor) a drug in clinical trials for cancer treatment, is an inhibitor of multiple kinases important in angiogenesis (Raf-1 kinase, VEGFR-2, VEGFR-3, PDGFR-ï¢)ï©. In this study, we assessed the efficacy of Sor as a potential therapy for PH, and hypothesized that Sor prevents the development of both a conventional and an augmented rodent model of PH. We performed studies in Dahl Salt-Sensitive rats (SS) exposed to hypoxia alone and in combination with the VEGFR-2 inhibitor, SU5416, known to induce a well-characterized augmented PH phenotype. Rats were, thus, divided into 5 groups: normoxia/vehicle (Norm), hypoxia/vehicle (H), hypoxia/ SU5416 (H-SU), hypoxia/Sorafenib (H-Sor) and hypoxia/ SU5416/ Sorafenib (H-SU-Sor). Except for the Norm group, all rats were maintained in a hypoxia chamber with a FiO2 of 10%. Rats received a single injection of SU5416 on Day 1 (20 mg/kg) and Sor solution was administered daily by gavage (2.5mg/kg). After 3.5 weeks, all rats were assessed by open chest catheterizations for pulmonary vascular and right ventricular pressures. Lung and heart tissue were harvested for histological and microarray analyses. Our results showed H-SU rats developed severe PH with changes in hemodynamic and histologic parameters when compared to Norm controls while rats exposed to H alone only displayed mildly elevated pressures compared with Norm. There was no significant change in pressures in the H-Sor or H-SU-Sor compared to Norm. Histopathology demonstrated a dramatic prevention of the PH phenotype in the H-SU-Sor rats with no significant remodeling compared with H-SU rats. Expression profiling data from H (n=4) and H-SU (n=3) rat lungs were compared to Norm (n=4) using normalization in R and SAM (Î´>.639,) (minimum fold change >1.4). With false discovery rates (FDR) of 6.5% in hypoxia and 1.6% in H-SU, 1019 and 465 genes, respectively, were differentially-regulated compared to Norm. In addition, 38 genes were differentially expressed between H-SU and H-SU-Sor (n=4, FDR 6.7%) revealing a molecular signature with potentially novel target genes of Sor. Five differentially expressed genes (Tgfï¢3, C1qg, Nexn, Frzb, and Plaur) were examined by real-time RT-PCR and three were further validated by immunohistochemistry confirming the regulation on protein level. Based on the known pathways of hypoxic-induced PH and Sor, we further utilized immunohistochemistry to show the up-regulation of mediators of the MAPK cascade in the H and H-SU models of PH with subsequent, down-regulation by Sor. We therefore present Sor as a novel treatment for the development of severe PH and theorize that the MAPK cascade is a canonical pathway involved both in the development of PH and in the attenuation by Sor. This SuperSeries is composed of the following subset Series:; GSE8078: A Multi- Kinase Inhibitor Modulates Pulmonary Hypertension in a Rodent Model 1; GSE8132: A Multi- Kinase Inhibitor Modulates Pulmonary Hypertension in a Rodent Model 2 Experiment Overall Design: Refer to individual Series

Project description:Rationale: Pulmonary arterial hypertension is a common and potentially fatal complication of scleroderma that may involve inflammatory and autoimmune mechanisms. Alterations in the gene expression of peripheral blood mononuclear cells have been previously described in patients with pulmonary arterial hypertension. The ability to identify patients at risk for developing pulmonary hypertension would be clinically beneficial. Objective: To identify genes that are differentially expressed in peripheral blood mononuclear cells in scleroderma patients with and without pulmonary hypertension which could be used as biomarkers of disease for early diagnosis and provide insight into pathogenesis of pulmonary hypertension in at-risk populations. Methods and Results: Gene expression analysis was performed on a carefully characterized Microarray Cohort of scleroderma patients with (n=10) and without (n=10) pulmonary hypertension. Differentially expressed genes were confirmed in the Microarray Cohort and validated in a separate Validation Cohort of scleroderma patients with (n=15) and without (n=19) pulmonary hypertension by RT-qPCR. We identified inflammatory and immune-related genes including interleukin-7 receptor (IL-7R) and chemokine receptor 7 (CCR7) as differentially expressed in patients with scleroderma-associated pulmonary hypertension. Flow cytometry confirmed decreased expression of IL-7R on circulating CD4+ T cells from scleroderma patients with pulmonary hypertension. Conclusions: Differences exist in the expression of inflammatory and immune-related genes in peripheral blood cells derived from patients with scleroderma-related pulmonary hypertension compared to those with normal pulmonary artery pressures. These findings may have implications as biomarkers to screen at-risk populations to facilitate early diagnosis and provide insight into inflammatory and autoimmune mechanisms of scleroderma-related pulmonary hypertension. Gene expression analysis was performed on a carefully characterized Microarray Cohort of scleroderma patients with (n=10) and without (n=10) pulmonary hypertension. Differentially expressed genes were confirmed in the Microarray Cohort by RT-qPCR.

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