Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0001486 (Adenovirus)
 3,125 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adenovirus (Ad) endocytosis via alphav integrins requires activation of the lipid kinase phosphatidylinositol-3-OH kinase (PI3K). Previous studies have linked PI3K activity to both the Ras and Rho signaling cascades, each of which has the capacity to alter the host cell actin cytoskeleton. Ad interaction with cells also stimulates reorganization of cortical actin filaments and the formation of membrane ruffles (lamellipodia). We demonstrate here that members of the Rho family of small GTP binding proteins, Rac and CDC42, act downstream of PI3K to promote Ad endocytosis. Ad internalization was significantly reduced in cells treated with Clostridium difficile toxin B and in cells expressing a dominant-negative Rac or CDC42 but not a H-Ras protein. Viral endocytosis was also inhibited by cytochalasin D as well as by expression of effector domain mutants of Rac or CDC42 that impair cytoskeletal function but not JNK/MAP kinase pathway activation. Thus, Ad endocytosis requires assembly of the actin cytoskeleton, an event initiated by activation of PI3K and, subsequently, Rac and CDC42.
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PMID:Adenovirus endocytosis requires actin cytoskeleton reorganization mediated by Rho family GTPases. 976 25

Small GTPase Rho and its target Rho-kinase/ROK/ROCK play an important role in various cellular functions, including smooth muscle contraction, actin cytoskeleton organization, and cell adhesion and migration, all of which may be involved in the pathogenesis of arteriosclerosis. Here, we show that adenovirus-mediated transfer of dominant-negative Rho-kinase (DNRhoK) induces a marked regression of coronary constrictive remodeling and abolishes coronary vasospastic activity in vivo. Porcine coronary segments were chronically treated with interleukin-1beta, which resulted in the development of constrictive remodeling and vasospastic responses to serotonin, as previously reported. Adenovirus-mediated transfer of DNRhoK, but not that of beta-galactosidase, into the interleukin-1beta-treated coronary segment caused a marked regression of the constrictive remodeling and abolished the vasospastic activity in 3 weeks. Western blot analysis showed that the phosphorylation of adducin and the ezrin/radixin/moesin family, the target proteins of Rho-kinase, were upregulated at the coronary lesions and were significantly suppressed by the transfer of DNRHOK: These results indicate that Rho-kinase is substantially involved in coronary constrictive remodeling and vasospastic responses, both of which can be reversed by the selective inhibition of the molecule in our porcine model in vivo.
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PMID:Adenovirus-mediated transfer of dominant-negative rho-kinase induces a regression of coronary arteriosclerosis in pigs in vivo. 1130 71

Plasminogen activator inhibitor type-1 (PAI-1) plays an integral role not only in the regulation of fibrinolytic activity but also in the pathogenesis of atherosclerosis and hypertension. We investigated the signaling pathways of angiotensin II (Ang II) leading to PAI-1 gene expression. Ang II increased the PAI-1 mRNA and protein levels in a time- and dose-dependent manner through the Ang II type 1 receptor in vascular smooth muscle cells. PAI-1 gene promoter activity measured by luciferase assay was significantly increased by Ang II. PAI-1 mRNA stability was also increased by Ang II. Ang II-induced PAI-1 mRNA upregulation was inhibited by BAPTA-AM, genistein, and AG1478, suggesting that intracellular calcium, tyrosine kinase, and epidermal growth factor receptor transactivation are involved. Furthermore, PD98059, an inhibitor of extracellular signal-regulated kinase (ERK) kinase (MEK), almost completely suppressed Ang II-induced PAI-1 upregulation. Adenovirus-mediated overexpression of the dominant-negative form of Rho-kinase or Y27632, a Rho-kinase inhibitor, also completely prevented PAI-1 induction by Ang II without affecting Ang II-induced ERK activation. These data suggest that activation of MEK/ERK and Rho-kinase pathways plays a pivotal role in PAI-1 gene upregulation by Ang II. The Rho-kinase pathway may be a novel target to inhibit Ang II signaling, and its inhibition may be useful in the treatment of hypertension as well as atherosclerosis.
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PMID:Critical role of Rho-kinase and MEK/ERK pathways for angiotensin II-induced plasminogen activator inhibitor type-1 gene expression. 1134 89

We investigated the role of cdc42, a Rho GTPase family member, in insulin-induced glucose transport in 3T3-L1 adipocytes. Microinjection of anti-cdc42 antibody or cdc42 siRNA led to decreased insulin-induced and constitutively active G(q) (CA-G(q); Q209L)-induced GLUT4 translocation. Adenovirus-mediated expression of constitutively active cdc42 (CA-cdc42; V12) stimulated 2-deoxyglucose uptake to 56% of the maximal insulin response, and this was blocked by treatment with the phosphatidylinositol 3-kinase (PI3-kinase) inhibitor, wortmannin, or LY294002. Both insulin and CA-G(q) expression caused an increase in cdc42 activity, showing that cdc42 is activated by insulin and is downstream of G alpha(q/11) in this activation pathway. Immunoprecipitation experiments showed that insulin enhanced a direct association of cdc42 and p85, and both insulin treatment and CA-cdc42 expression stimulated PI3-kinase activity in immunoprecipitates with anti-cdc42 antibody. Furthermore, the effects of insulin, CA-G(q), and CA-cdc42 on GLUT4 translocation or 2-deoxyglucose uptake were inhibited by microinjection of anti-protein kinase C lambda (PKC lambda) antibody or overexpression of a kinase-deficient PKC lambda construct. In summary, activated cdc42 can mediate 1) insulin-stimulated GLUT4 translocation and 2) glucose transport in a PI3-kinase-dependent manner. 3) Insulin treatment and constitutively active G(q) expression can enhance the cdc42 activity state as well as the association of cdc42 with activated PI3-kinase. 4) PKC lambda inhibition blocks CA-cdc42, CA-G(q), and insulin-stimulated GLUT4 translocation. Taken together, these data indicate that cdc42 can mediate insulin signaling to GLUT4 translocation and lies downstream of G alpha(q/11) and upstream of PI3-kinase and PKC lambda in this stimulatory pathway.
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PMID:Cdc42 is a Rho GTPase family member that can mediate insulin signaling to glucose transport in 3T3-L1 adipocytes. 1256 59

The Rho/Rho-kinase pathway in the nucleus tractus solitarii (NTS) of the brain stem contributes to blood pressure regulation. Activation of this pathway might be involved in the central nervous system mechanisms of hypertension. The aim of the present study was to determine whether baroreflex control of heart rate is altered by inhibition of Rho-kinase in the NTS. Adenovirus vectors encoding dominant-negative Rho-kinase or beta-galactosidase were transfected into the nucleus tractus solitarii of Wistar Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Baroreflex control of heart rate was examined by changing arterial pressure with an intravenous infusion of phenylephrine or sodium nitroprusside. The maximum gain of baroreflex control of heart rate was attenuated in SHR compared with WKY before the gene transfer. Transfection of adenovirus vectors encoding dominant-negative Rho-kinase significantly augmented the maximum gain in both WKY and SHR. The extent of this augmentation, however, was greater in SHR than in WKY. After treatment with metoprolol, the maximum gain was significantly decreased in rats transfected with adenovirus vectors encoding dominant-negative Rho-kinase, but not in nontransfected rats. In contrast, after treatment with atropine, the maximum gain was greater in rats transfected with adenovirus vectors encoding dominant-negative Rho-kinase compared with nontransfected rats, although it was decreased in both groups. These results suggest that inhibition of Rho-kinase in the NTS augments baroreflex control of heart rate, in both WKY and SHR, probably because of a cardiac sympathoinhibitory effect.
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PMID:Inhibition of Rho-kinase in the brainstem augments baroreflex control of heart rate in rats. 1535 14

Characterization of cardiac MYPT2 (an isoform of the smooth muscle phosphatase [MP] target subunit, MYPT1) is described. Several features of MYPT2 and MYPT1 were similar, including: a specific interaction with the catalytic subunit of type 1 phosphatase, delta isoform (PP1cdelta); interaction of MYPT2 with the small heart-specific MP subunit; interaction of the C-terminal region of MYPT2 with the active form of RhoA; phosphorylation by Rho-kinase at an inhibitory site, Thr646 and thiophosphorylation at Thr646 inhibited activity of the MYPT2-PP1cdelta complex. MYPT2 activated PP1cdelta activity, using light chains from smooth and cardiac muscle, by reducing K(m) and increasing k(cat). The extent of activation (k(cat)) was greater than for MYPT1 and could reflect distinct N-terminal sequences in the two MYPT isoforms. Adenovirus-mediated gene transfer of MYPT2 and PP1cdelta reduced the phosphorylation level of cardiac light chains following stimulation with A23187. Overexpression of MYPT2 and PP1cdelta blocked the angiotensin II-induced sarcomere organization in cultured cardiomyocytes. Electron microscopy indicated locations of MYPTs, at, or close to, the Z-line, the A band and mitochondria. Similarity of the two MYPT isoforms suggests common enzymatic mechanisms and regulation. Cardiac myosin is a substrate for the MYPT2 holoenzyme, but the Z-line location raises the possibility of other substrates.
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PMID:Characterization and function of MYPT2, a target subunit of myosin phosphatase in heart. 1643 Oct 80

In previous studies, we have demonstrated that RhoA/B-dependent signaling regulates TGFbeta-induced rapid actin reorganization in Swiss 3T3 fibroblasts. Here we report that TGFbeta regulates long-term actin remodeling by increasing the steady-state mRNA levels of the RhoB gene in mouse Swiss 3T3 fibroblasts and human hepatoma HepG2 cells. We show that this regulation is specific for the RhoB gene and is facilitated by enhanced activity of the RhoB promoter. Adenovirus-mediated gene transfer of Smad2 and Smad3 in Swiss 3T3 fibroblasts induced transcription of the endogenous RhoB gene but not the RhoA gene. Interestingly, in JEG-3 choriocarcinoma cells that lack endogenous Smad3, TGFbeta-induced transcriptional up-regulation of the RhoB gene was not observed, but it was restored by adenoviral Smad3 overexpression. In addition, Smad2 and Smad3 triggered activation of RhoA and RhoB GTPases and long-term actin reorganization in Swiss 3T3 fibroblasts. Finally, Smad3, and to a lesser extent Smad2, induced transcription of the alpha-smooth muscle actin (alpha-SMA) gene, and enhanced the incorporation of alpha-SMA into microfilaments in Swiss 3T3 fibroblasts. These data reveal a novel mechanism of cross-talk between the classical TGFbeta/Smad pathway and Rho GTPases, regulating the rapid and the long-term actin reorganization that may control the fibroblast-myofibroblast differentiation program.
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PMID:A novel mechanism of TGFbeta-induced actin reorganization mediated by Smad proteins and Rho GTPases. 1863 Nov 73

Insulin resistance associated with Type 2 diabetes contributes to impaired vasorelaxation and therefore contributes to the enhanced incidence of hypertension observed in diabetes. In this study, we examined the role of insulin on the association of the myosin-binding subunit of myosin phosphatase (MYPT1) to myosin phosphatase Rho-interacting protein (MRIP), a relatively novel member of the myosin phosphatase complex that directly binds RhoA in vascular smooth muscle cells (VSMCs). Through a series of molecular and cellular studies, we investigated whether insulin stimulates the binding of MRIP to MYPT1 and compared the results generated from VSMCs isolated from both Wistar-Kyoto (WKY) control and Goto-Kakizaki (GK) diabetic rats. We demonstrate for the first time that insulin stimulates the binding of MRIP to MYPT1 in a dose- and time-dependent manner, as determined by immunoprecipitation, implying a regulatory role for MRIP in insulin-induced vasodilation signaling via MYPT1 interaction. VSMCs from GK model of Type 2 diabetes had impaired insulin-induced MRIP/MYPT1 binding as well as reduced MRIP expression. Adenovirus-mediated overexpression of MRIP in GK VSMCs led to significantly improved insulin-stimulated MRIP/MYPT1 binding. Finally, insulin-stimulated MRIP translocation out of stress fibers, which was observed in control VSMCs, was impaired in GK VSMCs. We believe the impaired expression of MRIP, and therefore decreased insulin-stimulated MRIP/MYPT1 association, in the GK diabetic model may contribute to the impaired insulin-mediated vasodilation observed in the diabetic vasculature and provides a novel therapeutic strategy for the treatment of Type 2 diabetes.
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PMID:Impaired insulin-stimulated myosin phosphatase Rho-interacting protein signaling in diabetic Goto-Kakizaki vascular smooth muscle cells. 2232 72