RESUMO
Background: Previous studies have demonstrated that activated endothelial epithelial sodium channel (EnNaC) impairs vasodilatation, which contributes to salt-sensitive hypertension. Here, we investigate whether mesenteric artery (MA) EnNaC is involved in cold exposure-induced hypertension (CIH) and identify the underlying mechanisms in SD rats. Methods: One group of rats was housed at room temperature and served as control. Three groups of rats were kept in a 4°C cold incubator for 10 h/day; among which two groups were administrated with either benzamil (EnNaC blocker) or eplerenone (mineralocorticoid receptor antagonist, MR). Blood pressure (BP), vasodilatation, and endothelial function were measured with tail-cuff plethysmography, isometric myograph, and Total Nitric Oxide (NO) Assay kit, respectively. A cell-attached patch-clamp technique, in split-open MA, was used to determine the role of EnNaC in CIH rats. Furthermore, the plasma aldosterone levels were detected using an ELISA kit; and Western blot analysis was used to examine the relative expression levels of Sgk1 and Nedd4-2 proteins in the MA of SD rats. Results: We demonstrated that cold exposure increased BP, impaired vasodilatation, and caused endothelial dysfunction in rats. The activity of EnNaC significantly increased, concomitant with an increased level of plasma aldosterone and activation of Sgk1/Nedd4-2 signaling. Importantly, CIH was inhibited by either eplerenone or benzamil. It appeared that cold-induced decrease in NO production and impairment of endothelium-dependent relaxation (EDR) were significantly ameliorated by either eplerenone or benzamil in MA of CIH rats. Moreover, treatment of MAs with aldosterone resulted in an activation of EnNaC, a reduction of NO, and an impairment of EDR, which were significantly inhibited by either eplerenone or GSK650394 (Sgk1 inhibitor) or benzamil. Conclusion: Activation of EnNaC contributes to CIH; we suggest that pharmacological inhibition of the MR/Sgk1/Nedd4-2/EnNaC axis may be a potential therapeutic strategy for CIH.
RESUMO
To investigate the effect of short hairpin RNA (shRNA)-mediated silencing of CTGF and TIMP-1 in hepatic stellate cells (HSCs) on mRNA expression of TIMP-1, CTGF, and procollagen type-I (PC I), as well as secretion of extracellular matrix (ECM) proteins. Two recombinant expression plasmids harboring shRNAs against CTGF and TIMP-1 (psiRNA-GFP-CTGF and psiRNA-GFP-TIMP-1) were transfected alone or together into TGFb1-activated HSC-T6 cells. The mRNA expression levels of CTGF, TIMP-1, and PC I were detected by fluorescence quantitative PCR (FQ-PCR). The concentrations of secreted PC type-III, hyaluronate (HA), and laminin (LN) were measured by radioimmunoassay (RIA) of culture supernatants. FQ-PCR analysis showed that CTGFshRNA and TIMP-1shRNA specifically inhibited the expression of CTGF, TIMP-1, and PC I mRNA in activated HSC-T6 cells. The concentrations of secreted PC III, HA, and LN were decreased significantly in HSC-T6 cells with shRNA-silenced CTGF or TIMP-1 (P less than 0.01 or P less than 0.05). Moreover, HSC-T6 cells with shRNA-silenced CTGF and TIMP-1 showed a more robust decrease in synthesis of PC III, HA and LN (all, P less than 0.01), as well as in mRNA expression of PC I (P less than 0.05). CTGFshRNA and TIMP-1shRNA effectively inhibit expression of the respective target genes, as well as of PC I, and decrease secretion of ECM components from HSC-T6 cells. Silencing of both CTGF and TIMP-1 produces more robust effects than either in isolation. These data suggest that CTGF and TIMP-1 may be effective targets of shRNA-based gene therapy to treat liver fibrosis.
Assuntos
Fator de Crescimento do Tecido Conjuntivo/metabolismo , Matriz Extracelular/metabolismo , Células Estreladas do Fígado/metabolismo , Cirrose Hepática/patologia , RNA Interferente Pequeno/genética , Inibidor Tecidual de Metaloproteinase-1/metabolismo , Animais , Células Cultivadas , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Fator de Crescimento do Tecido Conjuntivo/genética , Regulação para Baixo , Regulação da Expressão Gênica , Inativação Gênica , Células Estreladas do Fígado/efeitos dos fármacos , Ácido Hialurônico/metabolismo , Laminina/metabolismo , Cirrose Hepática/metabolismo , Reação em Cadeia da Polimerase , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Inibidor Tecidual de Metaloproteinase-1/genética , Transfecção , Fator de Crescimento Transformador beta/metabolismoRESUMO
OBJECTIVE: To characterize genotypic resistance within HBV RT region in chronic hepatitis B (CHB) patients with nucleos(t)ide analogue (NA) treatment. METHODS: Serum samples of 229 CHB patients with NA treatment were obtained. Full-length HBV RT sequences were amplified, sequenced and analyzed, on the following NA resistant (NAr) mutations belonging to different NAr pathways. RESULTS: Among 229 HBV isolates, 14.41% (33/229) and 85.59% (196/229) were genotype B and C, respectively; and the patients with HBV genotype C may be more susceptible to develope resistant mutations than patients with HBV genotype B(chi2 = 2.95, P < 0.05). NAr mutations were detected in 63 CHB patients. Mutations were not found at rtI169, rtT184, rtA194 or rtS202. RtM204 mutations were detected at the highest frequency among 63 mutants (40/63, 63.49%) and found to display 11 combination mutation patterns, in which rtM204I were associated with rtL80I/V and rtL180M, and rtM204V were associated with rtL1l80M, respectively. Conclusions There are complicated mutation patterns in the HBV RT region for chronic hepatitis B (CHB) patients with nucleos(t)ide analogue (NA) treatment. RtM204V/I mutation was the highest.