BACKGROUND Akt plays diverse roles in humans.It is involved in the pathogenesis of type 2 diabetes mellitus(T2DM),which is caused by insulin resistance.Akt also plays a vital role in human platelet activation.Furtherm...BACKGROUND Akt plays diverse roles in humans.It is involved in the pathogenesis of type 2 diabetes mellitus(T2DM),which is caused by insulin resistance.Akt also plays a vital role in human platelet activation.Furthermore,the hippocampus is closely associated with memory and learning,and a decrease in hippocampal volume is reportedly associated with an insulin-resistant phenotype in T2DM patients without dementia.AIM To investigate the relationship between Akt phosphorylation in unstimulated platelets and the hippocampal volume in T2DM patients.METHODS Platelet-rich plasma(PRP)was prepared from the venous blood of patients with T2DM or age-matched controls.The pellet lysate of the centrifuged PRP was subjected to western blotting to analyse the phosphorylation of Akt,p38 mitogen-activated protein(MAP)kinase and glyceraldehyde 3-phosphate dehydrogenase(GAPDH).Phosphorylation levels were quantified by densitometric analysis.Hippocampal volume was analysed using a voxel-based specific regional analysis system for Alzheimer’s disease on magnetic resonance imaging,which proposes the Z-score as a parameter that reflects hippocampal volume.RESULTS The levels of phosphorylated Akt corrected with phosphorylated p38 MAP kinase were inversely correlated with the Z-scores in the T2DM subjects,whereas the levels of phosphorylated Akt corrected with GAPDH were not.However,this relationship was not observed in the control patients.CONCLUSION These results suggest that an inverse relationship may exist between platelet Akt activation and hippocampal atrophy in T2DM patients.Our findings provide insight into the molecular mechanisms underlying T2DM hippocampal atrophy.展开更多
Hepatocellular carcinoma(HCC) is one of the most common malignancies worldwide. The main etiologies of HCC are hepatitis B virus and hepatitis C virus(HCV), and non-hepatitis B/non-hepatitis C HCC(NBNCHCC) has also be...Hepatocellular carcinoma(HCC) is one of the most common malignancies worldwide. The main etiologies of HCC are hepatitis B virus and hepatitis C virus(HCV), and non-hepatitis B/non-hepatitis C HCC(NBNCHCC) has also been identified as an etiological factor. Although the incidence of HCV-related HCC in Japan has decreased slightly in recent years, that of NBNC-HCC has increased. The onset mechanism of NBNC-HCC, which has various etiologies, remains unclear; however, nonalcoholic steatohepatitis(NASH), a severe form of nonalcoholic fatty liver disease, is known to be an important risk factor for NBNC-HCC. Among the different advanced glycation end-products(AGEs) formed by the Maillard reaction, glyceraldehyde-derived AGEs, the predominant components of toxic AGEs(TAGE), have been associated with NASH and NBNC-HCC, including NASH-related HCC. Furthermore, the expression of the receptor for AGEs(RAGE) has been correlated with the malignant progression of HCC. Therefore, TAGE induce oxidative stress by binding with RAGE may, in turn, lead to adverse effects, such as fibrosis and malignant transformation, in hepatic stellate cells and tumor cells during NASH or NASH-related HCC progression. The aim of this review was to examine the contribution of the TAGE-RAGE axis in NASH-related HCC.展开更多
AIM:To study the formation of intracellular glyceraldehyde-derived advanced glycation end products(Glycer-AGEs)in the presence of high concentrations of fructose.METHODS:Cells of the human hepatocyte cell line Hep3B w...AIM:To study the formation of intracellular glyceraldehyde-derived advanced glycation end products(Glycer-AGEs)in the presence of high concentrations of fructose.METHODS:Cells of the human hepatocyte cell line Hep3B were incubated with or without fructose for five days,and the corresponding cell lysates were separated by two-dimensional gradient sodium dodecyl sulfate-polyacrylamide gel electrophoresis.Glycer-AGEs were detected with the anti-Glycer-AGEs antibody.Furthermore,the identification of the proteins that are modified by glyceraldehyde in the presence of high concentrations of fructose was conducted using matrixassisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS).The protein and m RNA levels were determined by Western blotting and realtime reverse transcription PCR,respectively.RESULTS:The results of the two-dimensional gradient sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated a greater amount of GlycerAGEs in the sample exposed to high concentrations of fructose than in the control.The detected GlycerAGEs showed isoelectric points in the range of 8.0-9.0and molecular weights in the range of 60-80 k Da.The heterogeneous nuclear ribonucleoprotein M(hn RNPM),which plays an important role in regulating gene expression by processing heterogeneous nuclear RNAs to form mature m RNAs,was identified as a modified protein using MALDI-TOF-MS.Increasing the concentration of fructose in the medium induced a concentration-dependent increase in the generated Glycer-AGEs.Furthermore,in an experiment using glyceraldehyde,which is a precursor of Glycer-AGEs,hn RNPM was found to be more easily glycated than the other proteins.CONCLUSION:The results suggest that glyceraldehyde-modified hn RNPM alters gene expression.This change may cause adverse effects in hepatocytes and may serve as a target for therapeutic intervention.展开更多
Advanced glycation endproducts (AGEs) are formed by the nonenzymatic reaction of sugars with proteins. Glycation may adversely affect proteins, such as by inducing a loss of function. It has been shown that glyceralde...Advanced glycation endproducts (AGEs) are formed by the nonenzymatic reaction of sugars with proteins. Glycation may adversely affect proteins, such as by inducing a loss of function. It has been shown that glyceraldehyde-derived AGEs (Glycer-AGEs) accumulate in the liver of patients with nonalcoholic steatohepatitis (NASH). Previously, we showed the formation of intracellular Glycer-AGEs upon exposure of hepatocytes to fructose in vitro, and identified an RNA-binding protein, heterogeneous nuclear ribonucleoprotein M (HNRNPM), as a target for glycation. However, the impact of glycated HNRNPM in NASH remains poorly understood. In this study, we examined gene expression changes caused by HNRNPM knockdown, and investigated the up- and down-regulated genes as noninvasive biomarker candidates for NASH. Microarray analysis after HNRNPM knockdown showed that the levels of 138 transcripts were increased, while those of 100 transcripts were decreased as compared with those in the control. Gene Ontology-based functional analysis showed that 14 upregulated and 9 downregulated genes were associated with the extracellular space, which may enable their detection using blood tests. Among these, six of the up- and down-regulated genes were associated with the extracellular exosome. These results suggest that the loss of HNRNPM function by glycation is reflected extracellularly. Therefore, the identified genes may serve as noninvasive biomarkers for Glycer-AGEs-related NASH.展开更多
基金Research Funding for Longevity Science from The National Center for Geriatrics and Gerontology,Japan,No.19-21and No.22-19.
文摘BACKGROUND Akt plays diverse roles in humans.It is involved in the pathogenesis of type 2 diabetes mellitus(T2DM),which is caused by insulin resistance.Akt also plays a vital role in human platelet activation.Furthermore,the hippocampus is closely associated with memory and learning,and a decrease in hippocampal volume is reportedly associated with an insulin-resistant phenotype in T2DM patients without dementia.AIM To investigate the relationship between Akt phosphorylation in unstimulated platelets and the hippocampal volume in T2DM patients.METHODS Platelet-rich plasma(PRP)was prepared from the venous blood of patients with T2DM or age-matched controls.The pellet lysate of the centrifuged PRP was subjected to western blotting to analyse the phosphorylation of Akt,p38 mitogen-activated protein(MAP)kinase and glyceraldehyde 3-phosphate dehydrogenase(GAPDH).Phosphorylation levels were quantified by densitometric analysis.Hippocampal volume was analysed using a voxel-based specific regional analysis system for Alzheimer’s disease on magnetic resonance imaging,which proposes the Z-score as a parameter that reflects hippocampal volume.RESULTS The levels of phosphorylated Akt corrected with phosphorylated p38 MAP kinase were inversely correlated with the Z-scores in the T2DM subjects,whereas the levels of phosphorylated Akt corrected with GAPDH were not.However,this relationship was not observed in the control patients.CONCLUSION These results suggest that an inverse relationship may exist between platelet Akt activation and hippocampal atrophy in T2DM patients.Our findings provide insight into the molecular mechanisms underlying T2DM hippocampal atrophy.
基金Supported by The Japan Society for the Promotion of Science(JSPS)KAKENHI,Grant No.22300264 and No.25282029(to Takeuchi M)the Ministry of Education,Culture,Sports,Science+1 种基金Technology(MEXT),Regional Innovation Strategy Support Program(to Takeuchi M)Kanazawa Medical University,No.SR2012-04
文摘Hepatocellular carcinoma(HCC) is one of the most common malignancies worldwide. The main etiologies of HCC are hepatitis B virus and hepatitis C virus(HCV), and non-hepatitis B/non-hepatitis C HCC(NBNCHCC) has also been identified as an etiological factor. Although the incidence of HCV-related HCC in Japan has decreased slightly in recent years, that of NBNC-HCC has increased. The onset mechanism of NBNC-HCC, which has various etiologies, remains unclear; however, nonalcoholic steatohepatitis(NASH), a severe form of nonalcoholic fatty liver disease, is known to be an important risk factor for NBNC-HCC. Among the different advanced glycation end-products(AGEs) formed by the Maillard reaction, glyceraldehyde-derived AGEs, the predominant components of toxic AGEs(TAGE), have been associated with NASH and NBNC-HCC, including NASH-related HCC. Furthermore, the expression of the receptor for AGEs(RAGE) has been correlated with the malignant progression of HCC. Therefore, TAGE induce oxidative stress by binding with RAGE may, in turn, lead to adverse effects, such as fibrosis and malignant transformation, in hepatic stellate cells and tumor cells during NASH or NASH-related HCC progression. The aim of this review was to examine the contribution of the TAGE-RAGE axis in NASH-related HCC.
基金Supported by Grants from the Japan Society for the Promotion of Science,No.22300264 and No.25282029
文摘AIM:To study the formation of intracellular glyceraldehyde-derived advanced glycation end products(Glycer-AGEs)in the presence of high concentrations of fructose.METHODS:Cells of the human hepatocyte cell line Hep3B were incubated with or without fructose for five days,and the corresponding cell lysates were separated by two-dimensional gradient sodium dodecyl sulfate-polyacrylamide gel electrophoresis.Glycer-AGEs were detected with the anti-Glycer-AGEs antibody.Furthermore,the identification of the proteins that are modified by glyceraldehyde in the presence of high concentrations of fructose was conducted using matrixassisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS).The protein and m RNA levels were determined by Western blotting and realtime reverse transcription PCR,respectively.RESULTS:The results of the two-dimensional gradient sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated a greater amount of GlycerAGEs in the sample exposed to high concentrations of fructose than in the control.The detected GlycerAGEs showed isoelectric points in the range of 8.0-9.0and molecular weights in the range of 60-80 k Da.The heterogeneous nuclear ribonucleoprotein M(hn RNPM),which plays an important role in regulating gene expression by processing heterogeneous nuclear RNAs to form mature m RNAs,was identified as a modified protein using MALDI-TOF-MS.Increasing the concentration of fructose in the medium induced a concentration-dependent increase in the generated Glycer-AGEs.Furthermore,in an experiment using glyceraldehyde,which is a precursor of Glycer-AGEs,hn RNPM was found to be more easily glycated than the other proteins.CONCLUSION:The results suggest that glyceraldehyde-modified hn RNPM alters gene expression.This change may cause adverse effects in hepatocytes and may serve as a target for therapeutic intervention.
文摘Advanced glycation endproducts (AGEs) are formed by the nonenzymatic reaction of sugars with proteins. Glycation may adversely affect proteins, such as by inducing a loss of function. It has been shown that glyceraldehyde-derived AGEs (Glycer-AGEs) accumulate in the liver of patients with nonalcoholic steatohepatitis (NASH). Previously, we showed the formation of intracellular Glycer-AGEs upon exposure of hepatocytes to fructose in vitro, and identified an RNA-binding protein, heterogeneous nuclear ribonucleoprotein M (HNRNPM), as a target for glycation. However, the impact of glycated HNRNPM in NASH remains poorly understood. In this study, we examined gene expression changes caused by HNRNPM knockdown, and investigated the up- and down-regulated genes as noninvasive biomarker candidates for NASH. Microarray analysis after HNRNPM knockdown showed that the levels of 138 transcripts were increased, while those of 100 transcripts were decreased as compared with those in the control. Gene Ontology-based functional analysis showed that 14 upregulated and 9 downregulated genes were associated with the extracellular space, which may enable their detection using blood tests. Among these, six of the up- and down-regulated genes were associated with the extracellular exosome. These results suggest that the loss of HNRNPM function by glycation is reflected extracellularly. Therefore, the identified genes may serve as noninvasive biomarkers for Glycer-AGEs-related NASH.
