Weili Yang

NFE2 Induces miR-423-5p to Promote Gluconeogenesis and Hyperglycemia by Repressing Hepatic FAM3A-ATP-Akt Pathway

Hepatic FAM3A expression is repressed under obese conditions, but the underlying mechanism remains unknown. This study determined the role and mechanism of miR-423-5p in hepatic glucose and lipid metabolism by repressing FAM3A expression. miR-423-5p expression was increased in the livers of obese diabetic mice and in patients with nonalcoholic fatty liver disease (NAFLD) with decreased FAM3A expression. miR-423-5p directly targeted FAM3A mRNA to repress its expression and the FAM3A-ATP-Akt pathway in cultured hepatocytes. Hepatic miR-423-5p inhibition suppressed gluconeogenesis and improved insulin resistance, hyperglycemia, and fatty liver in obese diabetic mice. In contrast, hepatic miR-423-5p overexpression promoted gluconeogenesis and hyperglycemia and increased lipid deposition in normal mice. miR-423-5p inhibition activated the FAM3A-ATP-Akt pathway and repressed gluconeogenic and lipogenic gene expression in diabetic mouse livers. The miR-423 precursor gene was further shown to be a target gene of NFE2, which induced miR-423-5p expression to repress the FAM3A-ATP-Akt pathway in cultured hepatocytes. Hepatic NFE2 overexpression upregulated miR-423-5p to repress the FAM3A-ATP-Akt pathway, promoting gluconeogenesis and lipid deposition and causing hyperglycemia in normal mice. In conclusion, under the obese condition, activation of the hepatic NFE2/miR-423-5p axis plays important roles in the progression of type 2 diabetes and NAFLD by repressing the FAM3A-ATP-Akt signaling pathway.

Comparison Analysis of Dysregulated LncRNA Profile in Mouse Plasma and Liver after Hepatic Ischemia/Reperfusion Injury

Long noncoding RNAs (LncRNAs) have been believed to be the major transcripts in various tissues and organs, and may play important roles in regulation of many biological processes. The current study determined the LncRNA profile in mouse plasma after liver ischemia/reperfusion injury (IRI) using microarray technology. Microarray assays revealed that 64 LncRNAs were upregulated, and 244 LncRNAs were downregulated in the plasma of liver IRI mouse. Among these dysregulated plasma LncRNAs, 59-61% were intergenic, 22-25% were antisense overlap, 8-12% were sense overlap and 6-7% were bidirectional. Ten dysregulated plasma LncRNAs were validated by quantitative PCR assays, confirming the accuracy of microarray analysis result. Comparison analysis between dysregulated plasma and liver LncRNA profile after liver IRI revealed that among the 308 dysregulated plasma LncRNAs, 245 LncRNAs were present in the liver, but remained unchanged. In contrast, among the 98 dysregulated liver LncRNAs after IRI, only 19 were present in the plasma, but remained unchanged. LncRNA AK139328 had been previously reported to be upregulated in the liver after IRI, and silencing of hepatic AK139328 ameliorated liver IRI. Both microarray and RT-PCR analyses failed to detect the presence of AK139328 in mouse plasma. In summary, the current study compared the difference between dysregulated LncRNA profile in mouse plasma and liver after liver IRI, and suggested that a group of dysregulated plasma LncRNAs have the potential of becoming novel biomarkers for evaluation of ischemic liver injury.

Long Non-coding RNA LncSHGL Recruits hnRNPA1 to Suppress Hepatic Gluconeogenesis and Lipogenesis

Mammalian genomes encode a huge number of long noncoding RNAs (lncRNAs) with unknown functions. This study determined the role and mechanism of a new lncRNA, lncRNA suppressor of hepatic gluconeogenesis and lipogenesis (lncSHGL), in regulating hepatic glucose/lipid metabolism. In the livers of obese mice and patients with nonalcoholic fatty liver disease, the expression levels of mouse lncSHGL and its human homologous lncRNA B4GALT1-AS1 were reduced. Hepatic lncSHGL restoration improved hyperglycemia, insulin resistance, and steatosis in obese diabetic mice, whereas hepatic lncSHGL inhibition promoted fasting hyperglycemia and lipid deposition in normal mice. lncSHGL overexpression increased Akt phosphorylation and repressed gluconeogenic and lipogenic gene expression in obese mouse livers, whereas lncSHGL inhibition exerted the opposite effects in normal mouse livers. Mechanistically, lncSHGL recruited heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) to enhance the translation efficiency of CALM mRNAs to increase calmodulin (CaM) protein level without affecting their transcription, leading to the activation of the phosphatidyl inositol 3-kinase (PI3K)/Akt pathway and repression of the mTOR/SREBP-1C pathway independent of insulin and calcium in hepatocytes. Hepatic hnRNPA1 overexpression also activated the CaM/Akt pathway and repressed the mTOR/SREBP-1C pathway to ameliorate hyperglycemia and steatosis in obese mice. In conclusion, lncSHGL is a novel insulin-independent suppressor of hepatic gluconeogenesis and lipogenesis. Activating the lncSHGL/hnRNPA1 axis represents a potential strategy for the treatment of type 2 diabetes and steatosis.

Hepatic Activation of the FAM3C-HSF1-CaM Pathway Attenuates Hyperglycemia of Obese Diabetic Mice

FAM3C is a member of the family with sequence similarity 3 (FAM3) gene family, and this study determined its role and mechanism in regulation of hepatic glucose/lipid metabolism. In obese diabetic mice, FAM3C expression was reduced in the liver, and hepatic FAM3C restoration improved insulin resistance, hyperglycemia, and fatty liver. FAM3C overexpression increased the expression of heat shock factor 1 (HSF1), calmodulin (CaM), and phosphorylated protein kinase B (Akt) and reduced that of gluconeogenic and lipogenic genes in diabetic mouse livers with the suppression of gluconeogenesis and lipid deposition. In cultured hepatocytes, FAM3C overexpression upregulated HSF1 expression, which elevated CaM protein level by inducing CALM1 transcription to activate Akt in a Ca2+- and insulin-independent manner. Furthermore, FAM3C overexpression promoted nuclear exclusion of FOXO1 and repressed gluconeogenic gene expression and gluconeogenesis in a CaM-dependent manner in hepatocytes. Hepatic HSF1 overexpression activated the CaM-Akt pathway to repress gluconeogenic and lipogenic gene expression and improve hyperglycemia and fatty liver in obese diabetic mice. In conclusion, the FAM3C-HSF1-CaM-Akt pathway plays important roles in regulating glucose and lipid metabolism in hepatocytes independent of insulin and calcium. Restoring hepatic FAM3C expression is beneficial for the management of type 2 diabetes and fatty liver.

FAM3A mediates PPARγ's protection in liver ischemia-reperfusion injury by activating Akt survival pathway and repressing inflammation and oxidative stress

FAM3A is a novel mitochondrial protein, and its biological function remains largely unknown. This study determined the role and mechanism of FAM3A in liver ischemia-reperfusion injury (IRI). In mouse liver after IRI, FAM3A expression was increased. FAM3A-deficient mice exhibited exaggerated liver damage with increased serum levels of AST, ALT, MPO, MDA and oxidative stress when compared with WT mice after liver IRI. FAM3A-deficient mouse livers had a decrease in ATP content, Akt activity and anti-apoptotic protein expression with an increase in apoptotic protein expression, inflammation and oxidative stress when compared WT mouse livers after IRI. Rosiglitazone pretreatment protected against liver IRI in wild type mice but not in FAM3A-deficient mice. In cultured hepatocytes, FAM3A overexpression protected against, whereas FAM3A deficiency exaggerated oxidative stress-induced cell death. FAM3A upregulation or FAM3A overexpression inhibited hypoxia/reoxygenation-induced activation of apoptotic gene and hepatocyte death in P2 receptor-dependent manner. FAM3A deficiency blunted rosiglitazones beneficial effects on Akt activation and cell survival in cultured hepatocytes. Collectively, FAM3A protects against liver IRI by activating Akt survival pathways, repressing inflammation and attenuating oxidative stress. Moreover, the protective effects of PPARγ agonist(s) on liver IRI are dependent on FAM3A-ATP-Akt pathway.

Hepatic MiR-291b-3p Mediated Glucose Metabolism by Directly Targeting p65 to Upregulate PTEN Expression.

Several studies have suggested an important role of miR-291b-3p in the development of embryonic stem cells. In previous study, we found that the expression of miR-291b-3p was significantly upregulated in the liver of db/db mice. However, the role of miR-291b-3p in glucose metabolism and its underlying mechanisms remain unknown. In the present study, we demonstrated that miR-291b-3p was abundantly expressed in the liver. Of note, hepatic miR-291b-3p expression was upregulated in HFD-fed mice and induced by fasting in C57BL/6 J normal mice. Importantly, hepatic inhibition miR-291b-3p expression ameliorated hyperglycemia and insulin resistance in HFD-fed mice, whereas hepatic overexpression of miR-291b-3p led to hyperglycemia and insulin resistance in C57BL/6 J normal mice. Further study revealed that miR-291b-3p suppressed insulin-stimulated AKT/GSK signaling and increased the expression of gluconeogenic genes in hepatocytes. Moreover, we identified that p65, a subunit of nuclear factor-κB (NF-κB), is a target of miR-291b-3p by bioinformatics analysis and luciferase reporter assay. Silencing of p65 significantly augmented the expression of PTEN and impaired AKT activation. In conclusion, we found novel evidence suggesting that hepatic miR-291b-3p mediated glycogen synthesis and gluconeogenesis through targeting p65 to regulate PTEN expression. Our findings indicate the therapeutic potential of miR-291b-3p inhibitor in hyperglycemia and insulin resistance.

FAM3 gene family: A promising therapeutical target for NAFLD and type 2 diabetes

Non-alcoholic fatty liver disease (NAFLD) and diabetes are severe public health issues worldwide. The Family with sequence similarity 3 (FAM3) gene family consists of four members designated as FAM3A, FAM3B, FAM3C and FAM3D, respectively. Recently, there had been increasing evidence that FAM3A, FAM3B and FAM3C are important regulators of glucose and lipid metabolism. FAM3A expression is reduced in the livers of diabetic rodents and NAFLD patients. Hepatic FAM3A restoration activates ATP-P2 receptor-Akt and AMPK pathways to attenuate steatosis and hyperglycemia in obese diabetic mice. FAM3C expression is also reduced in the liver under diabetic condition. FAM3C is a new hepatokine that activates HSF1-CaM-Akt pathway and represses mTOR-SREBP1-FAS pathway to suppress hepatic gluconeogenesis and lipogenesis. In contrast, hepatic expression of FAM3B, also called PANDER, is increased under obese state. FAM3B promotes hepatic lipogenesis and gluconeogenesis by repressing Akt and AMPK activities, and activating lipogenic pathway. Under obese state, the imbalance among hepatic FAM3A, FAM3B and FAM3C signaling networks plays important roles in the pathogenesis of NAFLD and type 2 diabetes. This review briefly discussed the latest research progress on the roles and mechanisms of FAM3A, FAM3B and FAM3C in the regulation of hepatic glucose and lipid metabolism.

Novel Targets for Treating Ischemia-Reperfusion Injury in the Liver

Liver ischemia-reperfusion injury (IRI) is a major complication of hemorrhagic shock, liver transplantation, and other liver surgeries. It is one of the leading causes for post-surgery hepatic dysfunction, always leading to morbidity and mortality. Several strategies, such as low-temperature reperfusion and ischemic preconditioning, are useful for ameliorating liver IRI in animal models. However, these methods are difficult to perform in clinical surgeries. It has been reported that the activation of peroxisome proliferator activated receptor gamma (PPARγ) protects the liver against IRI, but with unidentified direct target gene(s) and unclear mechanism(s). Recently, FAM3A, a direct target gene of PPARγ, had been shown to mediate PPARγ’s protective effects in liver IRI. Moreover, noncoding RNAs, including LncRNAs and miRNAs, had also been reported to play important roles in the process of hepatic IRI. This review briefly discussed the roles and mechanisms of several classes of important molecules, including PPARγ, FAM3A, miRNAs, and LncRNAs, in liver IRI. In particular, oral administration of PPARγ agonists before liver surgery or liver transplantation to activate hepatic FAM3A pathways holds great promise for attenuating human liver IRI.

The DrugPattern tool for drug set enrichment analysis and its prediction for beneficial effects of oxLDL on type 2 diabetes

Enrichment analysis methods, e.g., gene set enrichment analysis, represent one class of important bioinformatical resources for mining patterns in biomedical datasets. However, tools for inferring patterns and rules of a list of drugs are limited. In this study, we developed a web-based tool, DrugPattern, for drug set enrichment analysis. We first collected and curated 7019 drug sets, including indications, adverse reactions, targets, pathways, etc. from public databases. For a list of interested drugs, DrugPattern then evaluates the significance of the enrichment of these drugs in each of the 7019 drug sets. To validate DrugPattern, we employed it for the prediction of the effects of oxidized low-density lipoprotein (oxLDL), a factor expected to be deleterious. We predicted that oxLDL has beneficial effects on some diseases, most of which were supported by evidence in the literature. Because DrugPattern predicted the potential beneficial effects of oxLDL in type 2 diabetes (T2D), animal experiments were then performed to further verify this prediction. As a result, the experimental evidences validated the DrugPattern prediction that oxLDL indeed has beneficial effects on T2D in the case of energy restriction. These data confirmed the prediction accuracy of our approach and revealed unexpected protective roles for oxLDL in various diseases. This study provides a tool to infer patterns and rules in biomedical datasets based on drug set enrichment analysis. DrugPattern is available at http://www.cuilab.cn/drugpattern.

Identification and Analysis of Human Sex-biased MicroRNAs

Sex differences are widely observed under various circumstances ranging from physiological processes to therapeutic responses, and a myriad of sex-biased genes have been identified. In recent years, transcriptomic datasets of microRNAs (miRNAs), an important class of non-coding RNAs, become increasingly accessible. However, comprehensive analysis of sex difference in miRNA expression has not been performed. Here, we identified the differentially-expressed miRNAs between males and females by examining the transcriptomic datasets available in public databases and conducted a systemic analysis of their biological characteristics. Consequently, we identified 73 female-biased miRNAs (FmiRs) and 163 male-biased miRNAs (MmiRs) across four tissues including brain, colorectal mucosa, peripheral blood, and cord blood. Our results suggest that compared to FmiRs, MmiRs tend to be clustered in the human genome and exhibit higher evolutionary rate, higher expression tissue specificity, and lower disease spectrum width. In addition, functional enrichment analysis of miRNAs show that FmiR genes are significantly associated with metabolism process and cell cycle process, whereas MmiR genes tend to be enriched for functions like histone modification and circadian rhythm. In all, the identification and analysis of sex-biased miRNAs together could provide new insights into the biological differences between females and males and facilitate the exploration of sex-biased disease susceptibility and therapy.