scholarly journals Hepatic HuR protects against the pathogenesis of non-alcoholic fatty liver disease by targeting PTEN

2021 ◽  
Vol 12 (3) ◽  
Author(s):  
Mi Tian ◽  
Jingjing Wang ◽  
Shangming Liu ◽  
Xinyun Li ◽  
Jingyuan Li ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Hepatic Steatosis ◽  
Chow Diet ◽  
Alcoholic Fatty Liver ◽  
Phosphatase And Tensin Homolog ◽  
Tensin Homolog ◽  
Pten Mrna ◽  
Normal Chow ◽  
Mice Liver

AbstractThe liver plays an important role in lipid and glucose metabolism. Here, we show the role of human antigen R (HuR), an RNA regulator protein, in hepatocyte steatosis and glucose metabolism. We investigated the level of HuR in the liver of mice fed a normal chow diet (NCD) and a high-fat diet (HFD). HuR was downregulated in the livers of HFD-fed mice. Liver-specific HuR knockout (HuRLKO) mice showed exacerbated HFD-induced hepatic steatosis along with enhanced glucose tolerance as compared with control mice. Mechanistically, HuR could bind to the adenylate uridylate-rich elements of phosphatase and tensin homolog deleted on the chromosome 10 (PTEN) mRNA 3′ untranslated region, resulting in the increased stability of Pten mRNA; genetic knockdown of HuR decreased the expression of PTEN. Finally, lentiviral overexpression of PTEN alleviated the development of hepatic steatosis in HuRLKO mice in vivo. Overall, HuR regulates lipid and glucose metabolism by targeting PTEN.

scholarly journals Hepatic HuR protects against the pathogenesis of non-alcoholic fatty liver disease

2020 ◽  
Author(s):  
Mi Tian ◽  
Xinyun Li ◽  
Jingyuan Li ◽  
Jianmin Yang ◽  
Cheng Zhang ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Hepatic Steatosis ◽  
High Fat Diet ◽  
Chow Diet ◽  
Alcoholic Fatty Liver ◽  
Over Expression ◽  
Regulator Protein ◽  
Normal Chow ◽  
Alcoholic Fatty Liver Disease

Abstract Background: Liver plays an important role in lipid and glucose metabolism. Human antigen R (HuR) as an RNA regulator protein participates in many disease processes. Here, we investigated the specific role of HuR in hepatic steatosis and glucose metabolism.Methods: We investigated the level of HuR in liver from mice fed a normal chow diet (NCD) and high fat diet (HFD). Liver specific HuR knockout (HuRLKO) mice were generated and challenged with an HFD. Lipid levels and glucose metabolism index were examined. Results: HuR was downregulated in livers of HFD-fed mice. HuRLKO mice showed exacerbated HFD-induced hepatic steatosis but improved glucose tolerance as compared with controls. Consistently, HuR inhibited lipid accumulation in hepatocytes. Mechanically, HuR could bind to the mRNA of phosphatase and tensin homology deleted on chromosome 10 (PTEN), thus increasing their stability and translation. Finally, PTEN over-expression alleviated HFD-induced hepatic steatosis in HuRLKO mice.Conclusion: HuR modulates lipid and glucose metabolism through regulating PTEN expression.

scholarly journals Role of Mcpip1 in obesity-induced hepatic steatosis as determined by myeloid and liver-specific conditional knockouts

2020 ◽  
Author(s):  
Natalia Pydyn ◽  
Dariusz Żurawek ◽  
Joanna Kozieł ◽  
Edyta Kuś ◽  
Kamila Wojnar-Lason ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Hepatic Steatosis ◽  
Systemic Inflammation ◽  
Hepatic Metabolism ◽  
Negative Regulator ◽  
Chow Diet ◽  
Alcoholic Fatty Liver ◽  
Hepatic Expression ◽  
Expression Of Genes ◽  
Myeloid Leukocytes

AbstractMonocyte chemoattractant protein-induced protein 1 (MCPIP1, alias Regnase1) is a negative regulator of inflammation, acting through cleavage of transcripts coding for proinflammatory cytokines and by inhibition of NFκB activity. Moreover, it was demonstrated, that MCPIP1 regulates lipid metabolism both in adipose tissue and hepatocytes. In this study, we investigated the effects of tissue-specific Mcpip1 deletion on the regulation of hepatic metabolism and development of non-alcoholic fatty liver disease (NAFLD).We used knock-in control Mcpip1fl/fl mice and animals with deletion of Mcpip1 in myeloid leukocytes (Mcpip1fl/flLysMCre) and in hepatocytes (Mcpip1fl/flAlbCre), which were fed chow or a high-fat diet (HFD) for 12 weeks. Mcpip1fl/flLysMCre mice were fed a chow diet were characterized by a significantly reduced hepatic expression of genes regulating lipid and glucose metabolism, which subsequently resulted in hypoglycemia and dyslipidemia. These animals also displayed systemic inflammation, demonstrated by increased concentrations of cytokines in the plasma. On the other hand, there were no significant changes in phenotype in Mcpip1fl/flAlbCre mice. Although we detected a reduced hepatic expression of genes regulating glucose metabolism and β-oxidation in these mice, they remained asymptomatic. Upon feeding them a HFD, Mcpip1fl/flLysMCre mice did not develop obesity, glucose intolerance, nor hepatic steatosis, but were characterized by hypoglycemia and dyslipidemia, along with proinflammatory phenotype with symptoms of cachexia. Mcpip1fl/flAlbCre animals, following a HFD, became hypercholesterolemic, but accumulated lipids in the liver at the same level as Mcpip1fl/fl mice, and no changes in the level of soluble factors tested in the plasma were detected.In conclusion, we have demonstrated that Mcpip1 protein plays an important role in the liver homeostasis. Depletion of Mcpip1 in myeloid leukocytes, followed by systemic inflammation, has a more pronounced effect on controlling liver metabolism and homeostasis than the depletion of Mcpip1 in hepatocytes.

Metabolic in Vivo Labeling Highlights Differences of Metabolically Active Microbes from the Mucosal Gastrointestinal Microbiome between High-Fat and Normal Chow Diet

2017 ◽  
Vol 16 (4) ◽  
pp. 1593-1604 ◽  
Author(s):  
Andreas Oberbach ◽  
Sven-Bastiaan Haange ◽  
Nadine Schlichting ◽  
Marco Heinrich ◽  
Stefanie Lehmann ◽  
...  
Keyword(s):  
Chow Diet ◽  
High Fat ◽  
Gastrointestinal Microbiome ◽  
In Vivo Labeling ◽  
Normal Chow ◽  
Normal Chow Diet

Specific Deletion of CASK in Pancreatic β Cells Affects Glucose Homeostasis and Improves Insulin Sensitivity in Obese Mice by Reducing Hyperinsulinemia Running Title: β Cell CASK Deletion Reduces Hyperinsulinemia

2021 ◽  
Author(s):  
Xingjing Liu ◽  
Peng Sun ◽  
Qingzhao Yuan ◽  
Jinyang Xie ◽  
Ting Xiao ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Secretion ◽  
Insulin Sensitivity ◽  
Glucose Homeostasis ◽  
Chow Diet ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
Calcium Calmodulin Dependent ◽  
Normal Chow

Calcium/calmodulin-dependent serine protein kinase (CASK) is involved in the secretion of insulin vesicles in pancreatic β-cells. The present study revealed a new <i>in vivo </i>role of CASK in glucose homeostasis during the progression of type 2 diabetes mellitus (T2DM). A Cre-loxP system was used to specifically delete the <i>Cask </i>gene in mouse β-cells (βCASKKO), and the glucose metabolism was evaluated in <a>βCASKKO</a> mice fed a normal chow diet (ND) or a high-fat diet (HFD). ND-fed mice exhibited impaired insulin secretion in response to glucose stimulation. Transmission electron microscopy showed significantly reduced numbers of insulin granules at or near the cell membrane in the islets of βCASKKO mice. By contrast, HFD-fed βCASKKO mice showed reduced blood glucose and a partial relief of hyperinsulinemia and insulin resistance when compared to HFD-fed wildtype mice. The IRS1/PI3K/AKT signaling pathway was upregulated in the adipose tissue of HFD-βCASKKO mice. These results indicated that knockout of the <i>Cask</i> gene in β cells had a diverse effect on glucose homeostasis: reduced insulin secretion in ND-fed mice, but improves insulin sensitivity in HFD-fed mice. Therefore, CASK appears to function in the insulin secretion and contributes to hyperinsulinemia and insulin resistance during the development of obesity-related T2DM.

scholarly journals BMI1 promotes cardiac fibrosis in ischemia-induced heart failure via the PTEN-PI3K/Akt-mTOR signaling pathway

2019 ◽  
Vol 316 (1) ◽  
pp. H61-H69 ◽  
Author(s):  
Wenbo Yang ◽  
Zhijun Wu ◽  
Ke Yang ◽  
Yanxin Han ◽  
Yanjia Chen ◽  
...  
Keyword(s):  
Cardiac Fibrosis ◽  
Mammalian Target Of Rapamycin ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatase And Tensin Homolog ◽  
B Lymphoma ◽  
Tensin Homolog ◽  
And Migration ◽  
Proliferation And Migration

Cardiac fibrosis has been known to play an important role in the etiology of heart failure after myocardial infarction (MI). B lymphoma Mo-MLV insertion region 1 homolog (BMI1), a transcriptional repressor, is important for fibrogenesis in the kidneys. However, the effect of BMI1 on ischemia-induced cardiac fibrosis remains unclear. BMI1 was strongly expressed in the infarct region 1 wk post-MI in mice and was detected by Western blot and histological analyses. Lentivirus-mediated overexpression of BMI1 significantly promoted cardiac fibrosis, worsened cardiac function 4 wk after the intervention in vivo, and enhanced the proliferation and migration capabilities of fibroblasts in vitro , whereas downregulation of BMI1 decreased cardiac fibrosis and prevented cardiac dysfunction in mice 4 wk post-MI in vivo. Furthermore, upregulated BMI1 inhibited phosphatase and tensin homolog (PTEN) expression, enhanced phosphatidylinositol 3-kinase (PI3K) expression, and increased the phosphorylation level of Akt and mammalian target of rapamycin (mTOR) in mice 4 wk after lentiviral infection, which was in accordance with the changes seen in their infarcted myocardial tissues. At the same time, the effects of BMI1 on cardiac fibroblasts were reversed in vitro when these cells were exposed to NVP-BEZ235, a dual-kinase (PI3K/mTOR) inhibitor. In conclusion, BMI1 is associated with cardiac fibrosis and dysfunction after MI by regulating cardiac fibroblast proliferation and migration, and these effects could be partially explained by the regulation of the PTEN-PI3K/Akt-mTOR pathway. NEW & NOTEWORTHY Ischemia-induced B lymphoma Mo-MLV insertion region 1 homolog (BMI1) significantly promoted cardiac fibrosis and worsened cardiac function in vivo, whereas downregulation of BMI1 decreased cardiac fibrosis and prevented cardiac dysfunction in myocardial infarcted mice. BMI1 also enhanced proliferation and migration capabilities of fibroblasts in vitro; these effects were reversed by NVP-BEZ235. Effects of BMI1 on cardiac fibrosis could be partially explained by regulation of the phosphatase and tensin homolog-phosphatidylinositol 3-kinase/Akt-mammalian target of rapamycin pathway.

Zucker Lean Rats With Hepatic Steatosis Recapitulate Asymptomatic Metabolic Syndrome and Exhibit Greater Sensitivity to Drug-Induced Liver Injury Compared With Standard Nonclinical Sprague-Dawley Rat Model

2020 ◽  
Vol 48 (8) ◽  
pp. 994-1007
Author(s):  
Timothy P. LaBranche ◽  
Anna K. Kopec ◽  
Srinivasa R. Mantena ◽  
Brett D. Hollingshead ◽  
Andrew W. Harrington ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Pharmaceutical Industry ◽  
Liver Injury ◽  
Hepatic Steatosis ◽  
Sprague Dawley ◽  
Drug Induced ◽  
Drug Induced Liver Injury ◽  
Sd Rats ◽  
Normal Chow

Fatty liver disease is a potential risk factor for drug-induced liver injury (DILI). Despite advances in nonclinical in vitro and in vivo models to assess liver injury during drug development, the pharmaceutical industry is still plagued by idiosyncratic DILI. Here, we tested the hypothesis that certain features of asymptomatic metabolic syndrome (namely hepatic steatosis) increase the risk for DILI in certain phenotypes of the human population. Comparison of the Zucker Lean (ZL) and Zucker Fatty rats fed a high fat diet (HFD) revealed that HFD-fed ZL rats developed mild hepatic steatosis with compensatory hyperinsulinemia without increases in liver enzymes. We then challenged steatotic HFD-fed ZL rats and Sprague-Dawley (SD) rats fed normal chow, a nonclinical model widely used in the pharmaceutical industry, with acetaminophen overdose to induce liver injury. Observations in HFD-fed ZL rats included increased liver injury enzymes and greater incidence and severity of hepatic necrosis compared with similarly treated SD rats. The HFD-fed ZL rats also had disproportionately higher hepatic drug accumulation, which was linked with abnormal hepatocellular efflux transporter distribution. Here, we identify ZL rats with HFD-induced hepatic steatosis as a more sensitive nonclinical in vivo test system for modeling DILI compared with SD rats fed normal chow.

LINC00893 inhibits papillary thyroid cancer by suppressing AKT pathway via stabilizing PTEN

2020 ◽  
pp. 1-10
Author(s):  
Shujing Li ◽  
Yanyan Zhang ◽  
Jian Dong ◽  
Ruihuan Li ◽  
Bo Yu ◽  
...  
Keyword(s):  
Akt Pathway ◽  
Phosphatase And Tensin Homolog ◽  
Fused In Sarcoma ◽  
Tensin Homolog ◽  
Phosphorylated Akt ◽  
Pten Mrna ◽  
Non Coding Rnas ◽  
And Migration ◽  
Fus Protein ◽  
Proliferation And Migration

Long non-coding RNAs (lncRNAs) are important to the occurrence and advancement of human cancers. We found through GEPIA that LINC00893 was lowly expressed in thyroid carcinoma (THCA) tissues, whereas the specific functions of LINC00893 has never been reported in PTC. In the current study, we confirmed that LINC00893 was expressed at a low level in PTC cells. Through gain-of-function assays, we determined that LINC00893 overexpression abrogated proliferation and migration abilities of PTC cells. Through signal transduction reporter array we found that LINC00893 potentially modulated the signals of phosphatase and tensin homolog (PTEN)/AKT pathway. In addition, overexpression of LINC00893 increased the expression of PTEN but reduced the levels of phosphorylated AKT in PTC. Additionally, mechanism assays unveiled that LINC00893 stabilized PTEN mRNA via recruiting Fused in sarcoma (FUS) protein. Finally, rescue assays demonstrated that LINC00893 hampered the proliferation and migration of PTC cells via PTEN/AKT pathway. Together, our study first clarified that LINC00893 functions as a tumor suppressor in PTC by blocking AKT pathway through PTEN upregulation.

scholarly journals Adult enteric nervous system in health is maintained by a dynamic balance between neuronal apoptosis and neurogenesis

2017 ◽  
Vol 114 (18) ◽  
pp. E3709-E3718 ◽  
Author(s):  
Subhash Kulkarni ◽  
Maria-Adelaide Micci ◽  
Jenna Leser ◽  
Changsik Shin ◽  
Shiue-Cheng Tang ◽  
...  
Keyword(s):  
Nervous System ◽  
Enteric Nervous System ◽  
Dynamic Balance ◽  
Neuronal Cell ◽  
Cell Loss ◽  
Enteric Neurons ◽  
Phosphatase And Tensin Homolog ◽  
Tensin Homolog ◽  
Myenteric Ganglia

According to current dogma, there is little or no ongoing neurogenesis in the fully developed adult enteric nervous system. This lack of neurogenesis leaves unanswered the question of how enteric neuronal populations are maintained in adult guts, given previous reports of ongoing neuronal death. Here, we confirm that despite ongoing neuronal cell loss because of apoptosis in the myenteric ganglia of the adult small intestine, total myenteric neuronal numbers remain constant. This observed neuronal homeostasis is maintained by new neurons formed in vivo from dividing precursor cells that are located within myenteric ganglia and express both Nestin and p75NTR, but not the pan-glial marker Sox10. Mutation of the phosphatase and tensin homolog gene in this pool of adult precursors leads to an increase in enteric neuronal number, resulting in ganglioneuromatosis, modeling the corresponding disorder in humans. Taken together, our results show significant turnover and neurogenesis of adult enteric neurons and provide a paradigm for understanding the enteric nervous system in health and disease.

scholarly journals Podocyte-specific knockin of PTEN protects kidney from hyperglycemia

2018 ◽  
Vol 314 (6) ◽  
pp. F1096-F1107 ◽  
Author(s):  
Huizhen Wang ◽  
Ziwei Feng ◽  
Jianteng Xie ◽  
Feng Wen ◽  
Menglei Jv ◽  
...  
Keyword(s):  
Diabetic Kidney Disease ◽  
Therapeutic Strategy ◽  
Renal Protection ◽  
Phosphatase And Tensin Homolog ◽  
Tensin Homolog ◽  
Matrix Expansion ◽  
Interfering Rna

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) has proven to be downregulated in podocytes challenged with high glucose (HG), and knockout of PTEN in podocytes aggravated the progression of diabetic kidney disease (DKD). However, whether podocyte-specific knockin of PTEN protects the kidney against hyperglycemia in vivo remains unknown. The inducible podocyte-specific PTEN knockin (PPKI) mice were generated by crossing newly created transgenic loxP-stop- loxP-PTEN mice with podocin-iCreERT2 mice. Diabetes mellitus was induced in mice by intraperitoneal injection of streptozotocin at a dose of 150 mg/kg. In vitro, small interfering RNA and adenovirus interference were used to observe the role of PTEN in HG-treated podocytes. Our data demonstrated that PTEN was markedly reduced in the podocytes of patients with DKD and focal segmental glomerulosclerosis, as well as in those of db/db mice. Interestingly, podocyte-specific knockin of PTEN significantly alleviated albuminuria, mesangial matrix expansion, effacement of podocyte foot processes, and incrassation of glomerular basement membrane in diabetic PPKI mice compared with wild-type diabetic mice, whereas no alteration was observed in the level of blood glucose. The potential renal protection of overexpressed PTEN in podocytes was partly attributed with an improvement in autophagy and motility and the inhibition of apoptosis. Our results showed that podocyte-specific knockin of PTEN protected the kidney against hyperglycemia in vivo , suggesting that targeting PTEN might be a novel and promising therapeutic strategy against DKD.

scholarly journals Cardiac mTOR rescues the detrimental effects of diet-induced obesity in the heart after ischemia-reperfusion

2015 ◽  
Vol 308 (12) ◽  
pp. H1530-H1539 ◽  
Author(s):  
Toshinori Aoyagi ◽  
Jason K. Higa ◽  
Hiroko Aoyagi ◽  
Naaiko Yorichika ◽  
Briana K. Shimada ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Ex Vivo ◽  
Ischemia Reperfusion ◽  
Chow Diet ◽  
In Vivo Models ◽  
Myocardial Scarring ◽  
Diet Induced Obesity ◽  
Normal Chow ◽  
Normal Chow Diet

Diet-induced obesity deteriorates the recovery of cardiac function after ischemia-reperfusion (I/R) injury. While mechanistic target of rapamycin (mTOR) is a key mediator of energy metabolism, the effects of cardiac mTOR in ischemic injury under metabolic syndrome remains undefined. Using cardiac-specific transgenic mice overexpressing mTOR (mTOR-Tg mice), we studied the effect of mTOR on cardiac function in both ex vivo and in vivo models of I/R injury in high-fat diet (HFD)-induced obese mice. mTOR-Tg and wild-type (WT) mice were fed a HFD (60% fat by calories) for 12 wk. Glucose intolerance and insulin resistance induced by the HFD were comparable between WT HFD-fed and mTOR-Tg HFD-fed mice. Functional recovery after I/R in the ex vivo Langendorff perfusion model was significantly lower in HFD-fed mice than normal chow diet-fed mice. mTOR-Tg mice demonstrated better cardiac function recovery and had less of the necrotic markers creatine kinase and lactate dehydrogenase in both feeding conditions. Additionally, mTOR overexpression suppressed expression of proinflammatory cytokines, including IL-6 and TNF-α, in both feeding conditions after I/R injury. In vivo I/R models showed that at 1 wk after I/R, HFD-fed mice exhibited worse cardiac function and larger myocardial scarring along myofibers compared with normal chow diet-fed mice. In both feeding conditions, mTOR overexpression preserved cardiac function and prevented myocardial scarring. These findings suggest that cardiac mTOR overexpression is sufficient to prevent the detrimental effects of diet-induced obesity on the heart after I/R, by reducing cardiac dysfunction and myocardial scarring.

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