RESUMO
This study aims to investigate the effect of Golgi Protein 73 (GP73) on autophagy in human hepatoma line cells HepG2. We investigated the functional effects of GP73 on autophagy in hepatoma cell line HepG2 using immunofluoscence staining, Western blotting and real-time PCR. Our data showed that specific small interference RNA (siRNA) notably induced formation of autophagic vacuoles. In addition, upregulation of GP73 significantly inhibited formation of starvation-induced LC3-positive structures. We provide the first experimental evidence to show that GP73 may play an important role in the inhibitory regulation of autophagy. Therefore, our data suggest a new molecular mechanism for GP73-related hepatoma progression.
Assuntos
Autofagia , Proteínas de Membrana/fisiologia , Células Hep G2 , Humanos , Proteínas Associadas aos Microtúbulos/análise , Proteínas Associadas aos Microtúbulos/fisiologiaRESUMO
AIMS: Farnesyl pyrophosphate synthase (FPPS) is a key enzyme in the mevalonate pathway. In our previous study, we found that inhibition of FPPS attenuates cardiac hypertrophy in spontaneously hypertensive rats (SHRs) and prevents angiotensin (Ang) II-induced hypertrophy in cardiomyocytes. Here, we further investigate the role of FPPS in cardiac hypertrophy and heart failure (HF) using a transgenic (Tg) model, and its mechanisms. METHODS AND RESULTS: Tg mice with cardiac-specific expression of FPPS were studied as an experimental model. The results showed that Tg mice with overexpression of FPPS exhibited cardiac hypertrophy, fibrosis, and HF, as well as increased synthesis of farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate in heart tissue. These pathological changes were associated with the activation of RhoA and other known kinases in the hypertrophic signalling pathway, such as extracellular signal-related kinases 1/2 and p38. Adenoviral infection of FPPS in cultured neonatal cardiomyocytes induced a hypertrophic response characterized by an increased cell size and an increased extent of sarcomeric organization, as well as an increased activation profile of small GTPases and downstream protein kinases concordant with those seen in vivo. Further investigation showed a marked increase of FPPS protein levels in hypertrophic ventricles of patients with valvular heart disease. CONCLUSION: Taken together, these results suggest that FPPS may function as a potent regulator in myocardial remodelling. The FPPS-regulated signalling pathway is relevant to the pathological changes in cardiac hypertrophy and HF.
Assuntos
Cardiomegalia/metabolismo , Geraniltranstransferase/genética , Geraniltranstransferase/metabolismo , Insuficiência Cardíaca/metabolismo , Miocárdio/metabolismo , Miocárdio/patologia , Disfunção Ventricular Esquerda/metabolismo , Adenoviridae/genética , Animais , Cardiomegalia/fisiopatologia , Células Cultivadas , Modelos Animais de Doenças , Feminino , Expressão Gênica/fisiologia , Insuficiência Cardíaca/fisiopatologia , Doenças das Valvas Cardíacas/metabolismo , Doenças das Valvas Cardíacas/patologia , Humanos , Técnicas In Vitro , Sistema de Sinalização das MAP Quinases/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Camundongos Transgênicos , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Fosforilação , Fosfatos de Poli-Isoprenil/metabolismo , Transdução de Sinais/fisiologia , Disfunção Ventricular Esquerda/fisiopatologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismoRESUMO
Golgi glycoprotein 73(GP73) is a transmembrane glycoprotein residing in the cis-Golgi complex, which is strongly expressed in hepatocellular carcinoma (HCC) and secreted into the blood. It has been regarded as a promising serum tumor marker for the detection of HCC with higher sensitivity and specificity than AFP. GP73 is also significantly elevated in kidney cancer, prostate cancer, lung adenocarcinoma, esophageal cancer and seminomas; therefore, it would be helpful for the diagnosis of these diseases. However, the function of GP73 and the regulatory mechanism for its expression are unclear. In this article, the physical-chemical properties, the regulation of its expression, the relation with various cancers and the clinical applications of GP73 are reviewed.
Assuntos
Proteínas de Membrana , Biomarcadores Tumorais/metabolismo , Humanos , Rim/metabolismo , Hepatopatias/metabolismo , Proteínas de Membrana/química , Proteínas de Membrana/metabolismo , Proteínas de Membrana/fisiologia , Neoplasias/diagnóstico , Neoplasias/metabolismoRESUMO
Farnesyl pyrophosphate synthase (FPPS) is an essential enzyme in the mevalonate pathway and might be relevant to hypertension and other cardiovascular diseases. FPPS transgenic mice were produced by microinjecting a construct with the FPPS gene into fertilized eggs derived from an inbred C57BL/6 strain. Three mice were identified as carrying copies of the transgene using the PCR. Reverse transcription PCR and Western blotting showed that the transgene was expressed in heart, liver, lung, ear, brain, thymus, and blood vessels in the transgenic mouse. Pathological analysis (hematoxylin and eosin staining) showed that FPPS expression did not cause obvious pathological changes in multiple tissues of 6-week-old transgenic mice. This FPPS transgenic mouse model, may therefore, facilitate the investigation of the biological functions of FPPS in vivo.
