Pyruvate Supplementation Can Prevent HIIE-induced Metabolic Acidosis and Increase the Expression of MCT1/MCT4 in Skeletal Muscles of Rats / 中国生物化学与分子生物学报

As one of the causes of exercise-induced fatigue, exercise-induced metabolic acidosis has attracted much attention. The effect of pyruvate supplementation on exercise-induced metabolic acidosis is rarely reported, and its mechanism has not been fully elucidated. Monocarboxylate transporters (MCTs) play an important role in the maintenance of the acid-base balance, but it is not clear whether pyruvate can alleviate acidosis by increasing the expression of MCTs. In this study, pyruvate (616 mg/kg/day) was supplemented to rats for one week, and then acute HIIE was performed. The HIIE protocol comprised 13 repeats of a 60 s sprint session at 110% VO

Explore Mechanism of Modified Si Junzitang in Improving Acidic Microenvironment and Reversing Gastric Precancerous Lesions Based on MCT4/CD147 / 中国实验方剂学杂志

Objective:To observe the effect of modified Si Junzitang on the level of lactic acid in gastric mucosa and the expression of Carboxylic acid transporter 1（MCT1）， monocarboxylic acid transporter 4（MCT4）， and extracellular matrix metalloproteinase inducer （CD147）in rats with gastric precancerous lesions（GPL）. Method:Seventy-four SD male rats were randomly divided into normal group （12 rats） and model group （62 rats）. <italic>N</italic>-methyl-<italic>N'</italic>-nitro-<italic>N</italic>-nitrosoguanidine（MNNG）-ammonia compound method was used to establish GPL rat models， and at the 9^th week， the model rats were randomly divided into model group， folic acid group（2.7 mg·kg^-1）， modified Si Junzitang high， medium and low dose groups（12.6， 6.3， 3.15 g·kg^-1）， with 12 rats in each group. After intragastric administration for 12 weeks， the general conditions of the rats were observed. Hematoxylin-eosin（HE）staining was used to observe the histopathological changes of gastric mucosa in rats， chemical colorimetry was used to detect the content of lactic acid in gastric mucosa； immunohistochemistry and real-time polymerase chain reaction（Real-time PCR）were used to detect MCT1， MCT4， CD147 protein and mRNA expression in gastric mucosal tissues. Result:Modified Si Junzitang significantly improved the pathological manifestations in GPL rats such as gastric mucosal epithelial gland structure， disorder of arrangement and cell atypia. Compared with the normal group， the lactic acid content of the gastric mucosa tissue in the model group increased significantly（<italic>P</italic><0.01）， and the protein and mRNA expressions of MCT1， MCT4， CD147 significantly increased（<italic>P</italic><0.05， <italic>P</italic><0.01）. Compared with the model group， the lactic acid content in each dose group of modified Si Junzitang was significantly reduced（<italic>P</italic><0.05， <italic>P</italic><0.01）， and the protein expression levels of MCT4 and CD147 were also significantly reduced in each dose group of modified Si Junzitang（<italic>P</italic><0.05， <italic>P</italic><0.01）. The mRNA expression of MCT4 was significantly reduced in the middle and high dose groups（<italic>P</italic><0.05， <italic>P</italic><0.01）， and the mRNA expression of CD147 was significantly reduced in the high dose group（<italic>P</italic><0.05）. Modified Si Junzitang showed no significant regulatory effect on MCT1. Conclusion:Modified Si Junzitang can significantly improve the abnormal histopathology of gastric mucosal epithelium in GPL model rats. Its mechanism may be related to down-regulating the overexpression of MCT4 and CD147， inhibiting lactic acid outflow， and improving the acidic microenvironment of gastric mucosal epithelium.

MicroRNAs miR-1 and miR-206 Regulate Monocarboxylate Transporter-4 and Vascular Endothelial Growth Factor Gene Expression in Colorectal Cancer

Background: Colorectal cancer (CRC) is currently the third most common cancer type in males and the second most occurring in females. The role of microRNA (miRNA) in the development of colorectal cancer is notfully elucidated. Therefore, understanding the mechanistic interaction between miRNA and their target oncogenes may hold great importance as a possible target for interventional anticancer therapy Aims:To identify miRNAs that are part of the regulating pathway of Monocarboxylate Transporter-4 (MCT4) and Vascular Endothelial Growth Factor (VEGF) oncogenes.Study Design:We used publicly available prediction tools (e.g. TargetScan, MicroCosm, PicTar, and DIANA-microT-CDS) to identify the possible miRNA that target the two oncogenes. Methodology:We used the GeneMania database to visualize the network and verify gene names and remove ambiguity and duplications. Furthermore, we used miRTarBase database to identify experimentally validated targets which we used to further confirm miRNA-oncogene relationships. Finally, we utilized miR-Mfold web-tool to further visualize the circular structures and the simulated miR-1 and miR-206 targeting arrangements.Results:We found two putative miRNA (miR-1 and miR-206) that may downregulate MCT4 coded by SLC16A3gene and VEGF which is coded by VEGF gene. We found relationships between the validated target genes of miR-1 and miR-206 through GeneMania which we extracted from the literature. And we elucidated the proposed structure of these two miRNAs through miR-Mfold web-tool.Conclusion: Our results elucidated a novel regulation pathway in CRC cells and may suggest a potential therapeutic approach for CRC therapy. MiR-1 and miR-206 may help cells go to apoptosis and inhibit the angiogenesis of colorectal cancer cells by down-regulation of MCT4 and VEGF proteins in tumor tissues.

Effect of silencing monocarboxylate transporter 4 on the malignant biological behaviors of prostate cancer PC3 cells / 中国肿瘤生物治疗杂志

@#[Abstract] Objective: To investigate the effects of silencing monocarboxylate transporter 4 (MCT4) on the proliferation, migration and invasion of prostate cancer PC3 cells and its possible molecular mechanism. Methods: RNA interference technology was used to transfect siRNA-MCT4 (si-MCT4) and negative control plasmid (si-NC) into PC3 cells, respectively. The content of lactic acid in the cell culture medium of transfected PC3 cells was detected by lactic acid assay after culturing for 96 h. The proliferation, migration and invasion ability of PC3 cells were detected by CCK-8 and Transwell assay, respectively. Western blotting was used to detect the silencing effect and the expressions of integrin β 4-FAK-SRC-MEK-ERK signaling pathway associated proteins (integrin β4, p-FAK, p-SRC, p-ERK1/2, p-MEK1/2) and EMT associated proteins (E-cadherin and N-cadherin). Results: PC3 cell line with silenced MCT4 was successfully constructed. Compared with the control group, the content of extracellular lactic acid in the PC3 cell culture medium of the si-MCT4 group was significantly decreased (P<0.01), and the proliferation, migration and invasion of cells were significantly decreased (P<0.05 or P<0.01). Compared with the control group, the protein expressions of integrin β4, p-FAK, p-SRC, p-MEK1/2, p-ERK1/2 and N-cadherin were significantly decreased (all P<0.01), while the protein expression of E-cadherin was significantly increased (P<0.01). Conclusion: Silencing MCT4 can significantly inhibit the proliferation, migration and invasion of PC3 cells, the mechanism of which may be related to the inhibition of lactic acid level in cell culture medium and suppression of integrin β4-FAK-SRC-MEKERK signaling pathway associated proteins as well as EMT associated proteins.

Exercise training and selenium or a combined treatment ameliorates aberrant expression of glucose and lactate metabolic proteins in skeletal muscle in a rodent model of diabetes

Exercise training (ET) and selenium (SEL) were evaluated either individually or in combination (COMBI) for their effects on expression of glucose (AMPK, PGC-1alpha, GLUT-4) and lactate metabolic proteins (LDH, MCT-1, MCT-4, COX-IV) in heart and skeletal muscles in a rodent model (Goto-Kakisaki, GK) of diabetes. Forty GK rats either remained sedentary (SED), performed ET, received SEL, (5 micromol/kg body wt(-1)/day(-1)) or underwent both ET and SEL treatment for 6 wk. ET alone, SEL alone, or COMBI resulted in a significant lowering of lactate, glucose, and insulin levels as well as a reduction in HOMA-IR and AUC for glucose relative to SED. Additionally, ET alone, SEL alone, or COMBI increased glycogen content and citrate synthase (CS) activities in liver and muscles. However, their effects on glycogen content and CS activity were tissue-specific. In particular, ET alone, SEL alone, or COMBI induced upregulation of glucose (AMPK, PGC-1alpha, GLUT-4) and lactate (LDH, MCT-1, MCT-4, COX-IV) metabolic proteins relative to SED. However, their effects on glucose and lactate metabolic proteins also appeared to be tissue-specific. It seemed that glucose and lactate metabolic protein expression was not further enhanced with COMBI compared to that of ET alone or SEL alone. These data suggest that ET alone or SEL alone or COMBI represent a practical strategy for ameliorating aberrant expression of glucose and lactate metabolic proteins in diabetic GK rats.