Publications by authors named "Pawan Vohra"

Venous neointimal hyperplasia (VNH) causes hemodialysis vascular access failure. Here we tested whether VNH formation occurs in part due to local vessel hypoxia caused by surgical trauma to the vasa vasorum of the outflow vein at the time of arteriovenous fistula placement. Selective targeting of the adventitia of the outflow vein at the time of fistula creation was performed using a lentivirus-delivered small-hairpin RNA that inhibits VEGF-A expression.

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Exogenous brain-derived neurotrophic factor (BDNF) enhances Ca(2+) signaling and cell proliferation in human airway smooth muscle (ASM), especially with inflammation. Human ASM also expresses BDNF, raising the potential for autocrine/paracrine effects. The mechanisms by which ASM BDNF secretion occurs are not known.

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Venous neointimal hyperplasia (VNH) is responsible for hemodialysis vascular access malfunction. Here we tested whether VNH formation occurs, in part, due to vascular endothelial growth factor-A (VEGF-A) and matrix metalloproteinase (MMP)-9 gene expression causing adventitial fibroblast transdifferentiation to myofibroblasts (α-SMA-positive cells). These cells have increased proliferative and migratory capacity leading to VNH formation.

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Caveolae are flask-shaped plasma membrane invaginations expressing the scaffolding caveolin proteins. Although caveolins have been found in endothelium and epithelium (where they regulate nitric oxide synthase activity), their role in smooth muscle is still under investigation. We and others have previously shown that caveolae of human airway smooth muscle (ASM), which express caveolin-1, contain Ca(2+) and force regulatory proteins and are involved in mediating the effects of inflammatory cytokines such as TNF-α on intracellular Ca(2+) concentration responses to agonist.

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VEGF induces vascular permeability (VP) in ischemic diseases and cancer, leading to many pathophysiological consequences. The molecular mechanisms by which VEGF acts to induce hyperpermeability are poorly understood and in vivo models that easily facilitate real-time, genetic studies of VP do not exist. In the present study, we report a heat-inducible VEGF transgenic zebrafish (Danio rerio) model through which VP can be monitored in real time.

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The Na(+)/H(+) exchanger regulatory factor-2 (NHERF-2) is an integral component of almost all endothelial cells (ECs), yet its endothelial function is not known. Here, we found that NHERF-2, is a key regulator of endothelial homeostasis because NHERF-2-silenced ECs proliferate at a much higher rate even in the absence of mitogens such as VEGF compared with control ECs. We further show that the hyperproliferation phenotype of NHERF-2-silenced EC is because of an accelerated cell cycle that is probably caused by a combination of the following factors: increased cytoplasmic calcium, increased expression of c-Myc, increased expression of cyclin D1, and reduced expression of p27.

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Purpose: To test the hypothesis that there is increased expression of several profibrotic genes, including matrix metalloproteinase (MMP)-2 and MMP-9 and tissue inhibitors of metalloproteinase (TIMP-1 and TIMP-2), a disintegrin and metalloproteinase with thrombospondin motif-1 (ADAMTS-1), and fibroblast specific protein-1 (FSP-1) in a murine remnant kidney model.

Materials And Methods: Chronic kidney disease (CKD) was created in 10 C57BL/6 male mice (20-25 g) by performing a right nephrectomy and ligation of the upper pole of the left kidney (remnant kidney). Animals were sacrificed 42 days and 56 days later.

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The neurotransmitter dopamine and its dopamine receptor D2 (D2DR) agonists are known to inhibit vascular permeability factor/vascular endothelial growth factor (VEGF)-mediated angiogenesis and vascular permeability. Lung injury is a clinical syndrome associated with increased microvascular permeability. However, the effects of dopamine on pulmonary edema, a phenomenon critical to the pathophysiology of both acute and chronic lung injuries, have yet to be established.

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It is a challenge to develop a universal single drug that can treat breast cancer at single- or multiple-stage complications, yet remains nontoxic to normal cells. The challenge is even greater when breast cancer-specific, estrogen-based drugs are being developed that cannot act against multistaged breast cancer complications owing to the cells differential estrogen receptor (ER) expression status and their possession of drug-resistant and metastatic phenotypes. We report here the development of a first cationic lipid-conjugated estrogenic derivative (ESC8) that kills breast cancer cells independent of their ER expression status.

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Although the importance of RGS-GAIP-interacting protein (GIPC) in the biology of malignant cells is well known, the molecular mechanism of GIPC in the inhibition of tumor progression has not been identified. This study focused on elucidating the molecular role of GIPC in breast cancer progression. By using a human breast tumor specimen, an in vivo mouse model, and breast cancer cell lines, we showed for the first time that GIPC is involved in breast cancer progression through regulation of breast cancer cell proliferation, survival, and invasion.

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Vascular endothelial growth factor (VEGF)-induced receptor phosphorylation is the crucial step for initiating downstream signaling pathways that lead to angiogenesis or related pathophysiological outcomes. Our previous studies have shown that the neurotransmitter dopamine could inhibit VEGF-induced phosphorylation of VEGF receptor 2 (VEGFR-2), endothelial cell proliferation, migration, microvascular permeability, and thus, angiogenesis. In this study, we address the mechanism by which VEGFR-2 phosphorylation is regulated by dopamine.

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Purpose: Various studies have shown the importance of the GAIP interacting protein, COOH-terminus (GIPC, also known as Synectin) as a central adaptor molecule in different signaling pathways and as an important mediator of receptor stability. GIPC/Synectin is associated with different growth-promoting receptors such as insulin-like growth factor receptor I (IGF-IR) and integrins. These interactions were mediated through its PDZ domain.

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Purpose: This study aimed to investigate the expression of the ErbB family of receptor tyrosine kinases in pulmonary typical carcinoid and atypical carcinoid tumors and to understand the role of epidermal growth factor receptor (EGFR) signaling in pulmonary carcinoid tumor proliferation.

Experimental Design: Surgically resected typical carcinoid (n = 24) and atypical carcinoid (n = 7) tumor tissues were analyzed by immunohistochemical staining for EGFR, ErbB2, ErbB3, and ErbB4. Sequencing of tumor DNA of exons 18 to 21 of the EGFR gene and the KRAS gene was carried out.

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Mycobacterium avium complex (MAC) causes chronic lung disease in immunocompetent people and disseminated infection in patients with AIDS. MAC is intrinsically resistant to many conventional antimycobacterial agents, it develops drug resistance rapidly to macrolide antibiotics, and patients with MAC infection experience frequent relapses or the inability to completely eradicate the infection with current treatment. Treatment regimens are prolonged and complicated by drug toxicity or intolerances.

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The fungal pathogen Pneumocystis carinii remains the most prevalent opportunistic infection in patients infected with HIV. Fungal pheromone receptors are seven transmembrane domain G-protein-coupled receptors which are expressed on specific mating types, and have ligand-binding extracellular domains for specific pheromones from cells of the opposite mating type. We have cloned and characterized PCSTE3 from P.

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Fungal cell wall assembly is a complicated process involving multiple enzymes and coordinated signaling pathways. The cell wall integrity MAPK pathway acts to stabilize the fungal cell wall during conditions of elevated temperature by regulation of glucan synthesis. The upstream kinase, BCK1, is a critical component of this pathway.

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Mitogen-activated protein kinase (MAPK) pathways transfer environmental signals into intracellular events such as proliferation and differentiation. Fungi utilize a specific pheromone-induced MAPK pathway to regulate conjugation, formation of an ascus, and entry into meiosis. We have previously identified a MAPK, PCM, from the fungal opportunist Pneumocystis, responsible for causing severe pneumonia in patients with AIDS.

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A pheromone-induced mitogen activated protein kinase (MAPK) pathway controls mating in fungi by regulating gene transcription. In the opportunistic fungus Pneumocystis carinii, we have identified a protein containing a high-mobility group (HMG) motif which is homologous to the transcriptional activators STE11 of Schizosaccharomyces pombe and STE12 of Saccharomyces cerevisiae. In fungi, this transcriptional activator functions in sexual development, filamentous growth, and pathogenicity.

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Pneumocystis pneumonia remains the most common AIDS-defining opportunistic infection in people with HIV. The process by which Pneumocystis carinii constructs its cell wall is not well known, although recent studies reveal that molecules such as beta-1-3-glucan synthetase (GSC1) and environmental pH-responsive genes such as PHR1 are important for cell-wall integrity. In closely related fungi, a specific mitogen-activated protein kinase (MAPK) cascade regulates cell-wall assembly in response to elevated temperature.

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Pneumocystis carinii (PC) causes severe pneumonia in immunocompromised patients. PC is intrinsically resistant to treatment with azole antifungal medications. The enzyme lanosterol 14 alpha-demethylase (Erg11) is the target for azole antifungals.

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