👤 Zhenglin Du

Obesity is increasingly becoming a major public health problem worldwide. Peripheral LKB1 inhibits white fat generation, but the effect of central LKB1 on diet-induced obesity (DIO) is unknown. Therefore, we examined whether LKB1 over-expression in the hypothalamus can inhibit the development of obesity. Adult male Sprague-Dawley rats were anesthetized and placed in a stereotaxic apparatus. LKB1-AAV-EGFP (2.0 × 108 or 2.0 × 1010 vector genomes) or Control-AAV-EGFP (2.0 × 108 vector genomes) was injected into the third ventricle. After administration, the rats were fed a high-fat diet (HFD) for 9 weeks to induce obesity. Rats fed a chow fat diet were used as normal controls. LKB1 delivery decreased body weight, energy intake, fat mass, and serum lipid levels. LKB1 also improved HFD-induced hepatic fatty degeneration. Interestingly, LKB1 over-expression in the hypothalamus activated the AMPK-POMC neurons-sympathetic nervous system (SNS) axis, which can release epinephrine to promote white fat browning. Conversely, the elevated expression of MC3R/MC4R inhibited food intake. These two factors worked together to inhibit the development of obesity. LKB1 in the hypothalamus may have therapeutic potential for DIO through the activation of the AMPK-POMC neurons-SNS axis. Show less

The hypothalamic melanocortin 4 receptor (MC4R) pathway serves a critical role in regulating body weight. Loss of function (LoF) mutations in the MC4R pathway, including mutations in the pro-opiomelanocortin (POMC), prohormone convertase 1 (PCSK1), leptin receptor (LEPR), or MC4R genes, have been shown to cause early-onset severe obesity. Through a comprehensive epidemiological analysis of known and predicted LoF variants in the POMC, PCSK1, and LEPR genes, we sought to estimate the number of US individuals with biallelic MC4R pathway LoF variants. We predict ~650 α-melanocyte-stimulating hormone (MSH)/POMC, 8500 PCSK1, and 3600 LEPR homozygous and compound heterozygous individuals in the United States, cumulatively enumerating >12,800 MC4R pathway-deficient obese patients. Few of these variants have been genetically diagnosed to date. These estimates increase when we include a small subset of less rare variants: β-MSH/POMC,PCSK1 N221D, and a PCSK1 LoF variant (T640A). To further define the MC4R pathway and its potential impact on obesity, we tested associations between body mass index (BMI) and LoF mutation burden in the POMC, PCSK1, and LEPR genes in various populations. We show that the cumulative allele burden in individuals with two or more LoF alleles in one or more genes in the MC4R pathway are predisposed to a higher BMI than noncarriers or heterozygous LoF carriers with a defect in only one gene. Our analysis represents a genetically rationalized study of the hypothalamic MC4R pathway aimed at genetic patient stratification to determine which obese subpopulations should be studied to elucidate MC4R agonist (e.g., setmelanotide) treatment responsiveness. Show less

The Goto Kakizaki (GK) rats which can spontaneously develop type 2 diabetes (T2D), are generated by repeated inbreeding of Wistar rats with glucose intolerance. The glucose intolerance in GK rat is mainly attributed to the impairment in glucose-stimulated insulin secretion (GSIS). In addition, GK rat display a decrease in beta cell mass, and a change in insulin action. However, the genetic mechanism of these features remain unclear. In the present study, we analyzed the population variants of GK rats and control Wistar rats by whole genome sequencing and identified 1,839 and 1,333 specific amino acid changed (SAAC) genes in GK and Wistar rats, respectively. We also detected the putative artificial selective sweeps (PASS) regions in GK rat which were enriched with GK fixed variants and were under selected in the initial diabetic-driven derivation by homogeneity test with the fixed and polymorphic sites between GK and Wistar populations. Finally, we integrated the SAAC genes, PASS region genes and differentially expressed genes in GK pancreatic beta cells to reveal the genetic mechanism of the impairment in GSIS, a decrease in beta cell mass, and a change in insulin action in GK rat. The results showed that Show less

Understanding how intestinal microbiota alters energy homeostasis and lipid metabolism is a critical process in energy balance and health. However, the exact role of intestinal microbiota in the regulation of lipid metabolism in fish remains unclear. Here, we used two zebrafish models (germ-free and antibiotics-treated zebrafish) to identify the role of intestinal microbiota in lipid metabolism. Conventional and germ-free zebrafish larvae were fed with egg yolk. Transmission electron microscopy was used to detect the presence of lipid droplets in the intestinal epithelium. The results showed that, microbiota increased lipid accumulation in the intestinal epithelium. The mRNA sequencing technology was used to assess genes expression level. We found majority of the differentially expressed genes were related to lipid metabolism. Due to the limitation of germ-free zebrafish larvae, antibiotics-treated zebrafish were also used to identify the relationship between the gut microbiota and the host lipid metabolism. Oil-red staining showed antibiotics-treated zebrafish had less intestinal lipid accumulation than control group. The mRNA expression of genes related to lipid metabolism in liver and intestine was also quantified by using real-time PCR. The results indicated that Show less

Several studies have reported that apolipoprotein A5 (APOA5) is involved in the development of non-alcoholic fatty liver disease (NAFLD). However, no research has been performed regarding the association between APOA5 polymorphisms and the risk of NAFLD. This study aimed to explore the association between APOA5 gene polymorphisms and NAFLD in a Chinese Han population. Genotypes of the SNPs (rs10750097, rs1263173, rs17120035, rs3135507 and rs662799) of APOA5 in 232 NAFLD patients and 188 healthy controls were determined using polymerase chain reaction (PCR) analysis. Clinical characteristics were measured using biochemical methods. The five single nucleotide polymorphisms (SNPs) (rs10750097, rs1263173, rs17120035, rs3135507 and rs662799) of APOA5 showed no significant association with NAFLD (P > 0.05). The rs10750097 with G allele showed a higher serum level of alkaline phosphatase (ALP) compared with C allele in overall series and NAFLD patients (P < 0.05). The rs1263173(A/A) carriers showed a higher level of glucose compared to the non-carriers in overall series (P < 0.05). The rs17120035(T/T) carriers showed a lower plasma TG level in overall series and NAFLD patients (P < 0.05), and the rs662799(G/G) carriers showed higher levels of plasma triglyceride (TG), ALP, and lower level of high-density lipoprotein (HDL) compared to non-carriers in NAFLD patients (P < 0.05). No significant difference were observed on the clinic parameters of APOA5 rs3135507(T/T) carriers in both group of overall series and NAFLD patients (P > 0.05). The five SNPs (rs10750097, rs1263173, rs17120035, rs3135507 and rs662799) of APOA5 gene are not associated with the risk of NAFLD in the Chinese Han population. The genotypes of rs10750097(G/G), rs1263173(A/A), rs17120035(T/T), and rs662799(G/G) performed a significant effect on clinic characteristics in overall series and NAFLD patients, indicating that these polymorphisms may be associated with NAFLD. Show less

Parkinson's disease (PD) is a frequently occurring condition that resulted from the loss of midbrain neurons, which synthesize the neurotransmitter dopamine. In this study, we established mouse models of PD to investigate the expression of microRNA-128 (miR-128) and mechanism through which it affects apoptosis of dopamine (DA) neurons and the expression of excitatory amino acid transporter 4 (EAAT4) via binding to axis inhibition protein 1 (AXIN1). Gene expression microarray analysis was performed to screen differentially expressed miRNAs that are associated with PD. The targeting relationship between miR-128 and AXIN1 was verified via a bioinformatics prediction and dual-luciferase reporter gene assay. After separation, DA neurons were subjected to a series of inhibitors, activators and shRNAs to validate the mechanisms of miR-128 in controlling of AXIN1 in PD. Positive protein expression of AXIN1 and EAAT4 in DA neurons was determined using immunocytochemistry. miR-128 expression and the mRNA and protein levels of AXIN1 and EAAT4 were evaluated via RT-qPCR and Western blot analysis, respectively. DA neuron apoptosis was evaluated using TUNEL staining. We identified AXIN1 as an upregulated gene in PD based on the microarray data of GSE7621. AXIN1 was targeted and negatively mediated by miR-128. In the DA neurons, upregulated miR-128 expression or sh-AXIN1 increased the positive expression rate of EAAT4 together with mRNA and protein levels, but decreased the mRNA and protein levels of AXIN1, apoptosis rate along with the positive expression rate of AXIN1; however, the opposite trend was found in response to transfection with miR-128 inhibitors. Evidence from experimental models revealed that miR-128 might reduce apoptosis of DA neurons while increasing the expression of EAAT4 which might be related to the downregulation of AXIN1. Thus, miR-128 may serve as a potential target for the treatment of PD. Show less

This study was conducted to measure the concentration of branched chain amino acid (BCAA) in different species and detect the expression pattern of the liver We measured the concentration of BCAA in GK rats, induced T2D cynomolgus monkeys and T2D humans by liquid chromatography tandem mass spectrometry, and used real-time quantitative PCR to analyze the gene expression of In this study, we showed that GK rat BCAA concentrations were significantly reduced at 4 and 8 weeks ( Our results showed that BCAA concentrations changed at different times and by different amounts in different species and during different periods of T2D progress, and the significant changes of BCAA concentration in the three species indicated that BCAA might participate in the progress of T2D. The results suggested that the increased expression of Show less

Increasing levels of high-density lipoprotein (HDL) cholesterol through pharmacologic inhibition of cholesteryl ester transfer protein (CETP) is a potentially important strategy for prevention and treatment of cardiovascular disease (CVD). To use genetic variants in the CETP gene to assess potential risks and benefits of lifelong lower CETP activity on CVD and other outcomes. This prospective biobank study included 151 217 individuals aged 30 to 79 years who were enrolled from 5 urban and 5 rural areas of China from June 25, 2004, through July 15, 2008. All participants had baseline genotype data, 17 854 of whom had lipid measurements and 4657 of whom had lipoprotein particle measurements. Median follow-up of 9.2 years (interquartile range, 8.2-10.1 years) was completed January 1, 2016, through linkage to health insurance records and death and disease registries. Five CETP variants, including an East Asian loss-of-function variant (rs2303790), combined in a genetic score weighted to associations with HDL cholesterol levels. Baseline levels of lipids and lipoprotein particles, cardiovascular risk factors, incidence of carotid plaque and predefined major vascular and nonvascular diseases, and a phenome-wide range of diseases. Among the 151 217 individuals included in this study (58.4% women and 41.6% men), the mean (SD) age was 52.3 (10.9) years. Overall, the mean (SD) low-density lipoprotein (LDL) cholesterol level was 91 (27) mg/dL; HDL cholesterol level, 48 (12) mg/dL. CETP variants were strongly associated with higher concentrations of HDL cholesterol (eg, 6.1 [SE, 0.4] mg/dL per rs2303790-G allele; P = 9.4 × 10-47) but were not associated with lower LDL cholesterol levels. Within HDL particles, cholesterol esters were increased and triglycerides reduced, whereas within very low-density lipoprotein particles, cholesterol esters were reduced and triglycerides increased. When scaled to 10-mg/dL higher levels of HDL cholesterol, the CETP genetic score was not associated with occlusive CVD (18 550 events; odds ratio [OR], 0.98; 95% CI, 0.91-1.06), major coronary events (5767 events; OR, 1.08; 95% CI, 0.95-1.22), myocardial infarction (3118 events; OR, 1.14; 95% CI, 0.97-1.35), ischemic stroke (13 759 events; OR, 0.94; 95% CI, 0.86-1.02), intracerebral hemorrhage (6532 events; OR, 0.94; 95% CI, 0.83-1.06), or other vascular diseases or carotid plaque. Similarly, rs2303790 was not associated with any vascular diseases or plaque. No associations with nonvascular diseases were found other than an increased risk for eye diseases with rs2303790 (4090 events; OR, 1.43; 95% CI, 1.13-1.80; P = .003). CETP variants were associated with altered HDL metabolism but did not lower LDL cholesterol levels and had no significant association with risk for CVD. These results suggest that in the absence of reduced LDL cholesterol levels, increasing HDL cholesterol levels by inhibition of CETP may not confer significant benefits for CVD. Show less

Our preview studies showed TPI gene which encodes the Triosephosphate isomerase was overexpressed in human gastric cancer (GC) tissues. However, the potential molecular mechanisms how TPI influences the GC development is not clear. Here, we performed global gene expression profiling for TPI knockdown using microarrays in human GC cell line MGC-803 cells. The differentially expressed genes (DEGs) were identified using reverse transcription-quantitative polymerase chain reaction analysis. Then the DEGs were analyzed by an online software WebGestalt to perform the functional analysis, pathway analysis and network analysis. The protein-protein interaction (PPI) networks were visualized by Cytoscape and the module analysis was performed by ClusterONE. As a result, a total of 920 DEGs including 197 up- and 723 down-regulated genes were screened out. The DEGs were found to be significantly associated with the metabolic process, biological regulation, protein binding and ion binding. There were 11 significant pathways were enriched, and one of the most significant pathway was transcriptional misregulation in cancer (P<0.01), which contained common cancer-related genes, such as DUSP6, ETV5, IL6, PLAU, PPARG and HMGA2. Two PPI networks were constructed from BioGRID and TCGA_RNASeq_STAD, respectively. One network presented 25 genes with degree >10, and EGFR was the most "hub gene" with degree of 74. Four significant modules were identified and mainly enriched in protein domain of Histone and G-protein beta WD-40 repeat. Another network had 4 significant modules and they were associated with protein domain of MHC class I-like antigen recognition and Epidermal growth factor receptor ligand. In conclusion, DEGs and hub genes identified in the present study help us understand the molecular mechanisms of TPI in the carcinogenesis and progression of gastric cancer. Show less

Increased production of long-chain unsaturated fatty acids (LCUFA) can have a positive effect on the nutritional value of ruminant milk for human consumption. In nonruminant species, fatty acid elongase 5 (ELOVL5) is a key enzyme for endogenous synthesis of long-chain unsaturated fatty acids. However, whether ELOVL5 protein plays a role (if any) in ruminant mammary tissue remains unclear. In the present study, we assessed the mRNA abundance of ELOVL5 at 3 stages of lactation in goat mammary tissue. Results revealed that ELOVL5 had the lowest expression at peak lactation compared with the nonlactating and late-lactating periods. The ELOVL5 was overexpressed or knocked down to assess its role in goat mammary epithelial cells. Results revealed that ELOVL5 overexpression increased the expression of perilipin2 (PLIN2) and decreased diacylglycerolacyltransferase 2 (DGAT2) and fatty acid desaturase 2 (FADS2) mRNA, but had no effect on the expression of DGAT1, FADS1, and stearoyl-CoA desaturase 1 (SCD1). Overexpression of ELOVL5 decreased the concentration of C16:1n-7, whereas no significant change in C18:1n-7 and C18:1n-9 was observed. Knockdown of ELOVL5 decreased the expression of PLIN2 but had no effect on DGAT1, DGAT2, FADS1, FADS2, and SCD1 mRNA expression. Knockdown of ELOVL5 increased the concentration of C16:1n-7 and decreased that of C18:1n-7. The alterations of expression of genes related to lipid metabolism after overexpression or knockdown of ELOVL5 suggested a negative feedback regulation by the products of ELOVL5 activation. However, the content of triacylglycerol was not altered by knockdown or overexpression of ELOVL5 in goat mammary epithelial cells, which might have been due to the insufficient availability of substrate in vitro. Collectively, these are the first in vitro results highlighting an important role of ELOVL5 in the elongation of 16-carbon to 18-carbon unsaturated fatty acids in ruminant mammary cells. Show less

Obesity is causally associated with atherosclerosis, and adipose tissue (AT)-derived exosomes may be implicated in the metabolic complications of obesity. However, the precise role of AT-exosomes in atherogenesis remains unclear. We herein aimed to assess the effect of AT-exosomes on macrophage foam cell formation and polarization and subsequent atherosclerosis development. Four types of exosomes isolated from the supernatants of ex vivo subcutaneous AT and visceral AT (VAT) explants that were derived from wild-type mice and high-fat diet (HFD)-induced obese mice were effectively taken up by RAW264.7 macrophages. Both treatment with wild-type VAT exosomes and HFD-VAT exosomes, but not subcutaneous AT exosomes, markedly facilitated macrophage foam cell generation through the downregulation of ATP-binding cassette transporter (ABCA1 and ABCG1)-mediated cholesterol efflux. Decreased expression of liver X receptor-α was also observed. Among the 4 types of exosomes, only HFD-VAT exosomes significantly induced M1 phenotype transition and proinflammatory cytokine (tumor necrosis factor α and interleukin 6) secretion in RAW264.7 macrophages, which was accompanied by increased phosphorylation of NF-κB-p65 but not the cellular expression of NF-κB-p65 or IκB-α. Furthermore, systematic intravenous injection of HFD-VAT exosomes profoundly exacerbated atherosclerosis in hyperlipidemic apolipoprotein E-deficient mice, as indicated by the M1 marker (CD16/32 and inducible nitric oxide synthase)-positive areas and the Oil Red O/Sudan IV-stained area, without affecting the plasma lipid profile and body weight. This study demonstrated a proatherosclerotic role for HFD-VAT exosomes, which is exerted by regulating macrophage foam cell formation and polarization, indicating a novel link between AT and atherosclerosis in the context of obesity. Show less

The ability of liver to respond to changes in nutrient availability is essential for the maintenance of metabolic homeostasis. Autophagy encompasses mechanisms of cell survival, including capturing, degrading, and recycling of intracellular proteins and organelles in lysosomes. During negative nutrient status, autophagy provides substrates to sustain cellular metabolism and hence, tissue function. Severe negative energy balance in dairy cows is associated with fatty liver. The aim of this study was to investigate the hepatic autophagy status in dairy cows with severe fatty liver and to determine associations with biomarkers of liver function and inflammation. Liver and blood samples were collected from multiparous cows diagnosed as clinically healthy (n = 15) or with severe fatty liver (n = 15) at 3 to 9 d in milk. Liver tissue was biopsied by needle puncture, and serum samples were collected on 3 consecutive days via jugular venipuncture. Concentrations of free fatty acids and β-hydroxybutyrate were greater in cows with severe fatty liver. Milk production, dry matter intake, and concentration of glucose were all lower in cows with severe fatty liver. Activities of serum aspartate aminotransferase, alanine aminotransferase, glutamate dehydrogenase, and γ-glutamyl transferase were all greater in cows with severe fatty liver. Serum concentrations of haptoglobin and serum amyloid A were also markedly greater in cows with severe fatty liver. The mRNA expression of autophagosome formation-related gene ULK1 was lower in the liver of dairy cows with severe fatty liver. However, the expression of other autophagosome formation-related genes, beclin 1 (BECN1), phosphatidylinositol 3-kinase catalytic subunit type 3 (PIK3C3), autophagy-related gene (ATG) 3, ATG5, and ATG12, did not differ. More important, ubiquitinated proteins, protein expression of sequestosome-1 (SQSTM1, also called p62), and microtubule-associated protein 1 light chain 3 (MAP1LC3, also called LC3)-II was greater in cows with severe fatty liver. Transmission electron microscopy revealed an increased number of autophagosomes in the liver of dairy cows with severe fatty liver. Taken together, these results indicate that excessive lipid infiltration of the liver impairs autophagic activity that may lead to cellular damage and inflammation. Show less

Aging is a complex process accompanied with the decline of the different physiological functions. Numerous differentially expressed genes (DEGs) have been found in the aging brain of senescence-accelerated mouse P8 (SAMP8), however, it was challenging to screen out the crucial ones. This study aimed to explore the crucial genes and pathways in aging brain of SAMP8 mice, which would be beneficial for understanding the pathogenesis of brain aging. Firstly, 430 genes that are differentially expressed in SAMP8 mice versus SAMR1 mice were obtained from 9 gene expression studies, and gene-gene network was constructed. Clustering analysis and topological analysis were used to single out the hub genes from this network. Secondly, pathway enrichment analysis was utilized to identify the key pathways from the 430 DEGs, and the DEGs in key pathways were considered as functional genes. Thirdly, the inner-network between hub genes and functional genes was constructed, and the key genes were predicted. Parts of the key genes were experimentally verified by quantitative real-time PCR (qRT-PCR), and the associated transcription factors (TFs) were predicted. Our results revealed that 12 crucial genes might affect brain aging, including Trp53, Bcl2, Tnf, Casp9, Fos, Il6, Ptgs2, Il1b, Bdnf, Cdkn1a, Pik3c3, Rps6ka1, among which Casp9, Fos, Ptgs2, Cdkn1a, Pik3c3, and Rps6ka1 had been verified by qRT-PCR in 10-moth-old SAMP8 mice. Five functional groups including mitogen-activated protein kinase (MAPK) signaling pathway, neurotrophin signaling pathway, Hepatitis B, Alzheimer's disease and Oxytocin signaling pathway were significantly changed during aging process in SAMP8 mice. Two key transcription factors of c-Fos and C/EBPbeta were predicted by constructing a TF-target gene network. These putative genes and pathways are closely related to brain senescence and our results would gain new insight into the pathogenesis of brain aging. Show less

Functional characterization of disease-causing variants at risk loci has been a significant challenge. Here we report a high-throughput single-nucleotide polymorphisms sequencing (SNPs-seq) technology to simultaneously screen hundreds to thousands of SNPs for their allele-dependent protein-binding differences. This technology takes advantage of higher retention rate of protein-bound DNA oligos in protein purification column to quantitatively sequence these SNP-containing oligos. We apply this technology to test prostate cancer-risk loci and observe differential allelic protein binding in a significant number of selected SNPs. We also test a unique application of self-transcribing active regulatory region sequencing (STARR-seq) in characterizing allele-dependent transcriptional regulation and provide detailed functional analysis at two risk loci (RGS17 and ASCL2). Together, we introduce a powerful high-throughput pipeline for large-scale screening of functional SNPs at disease risk loci. Show less

Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is a life-threatening condition, and the lipid metabolism disorder is common in the development of this disease. This prospective observational study aimed to define the characteristics of plasma apolipoprotein A-V (apoA-V) in long-term outcome prediction of HBV-ACLF, and a total of 330 HBV-ACLF patients were included and followed for more than 12 months. In this cohort, the 4-week, 12-week, 24-week and 48-week cumulative mortality of HBV-ACLF was 18.2%(60/330), 50.9%(168/330), 59.7%(197/330) and 63.3%(209/330), respectively. As compared to survivors, the non-survivors had significantly lower concentrations of plasma apoA-V on admission. Plasma apoA-V concentrations were positively correlated with prothrombin time activity (PTA), and negatively correlated with interleukin-10, tumor necrosis factor-α, and iMELD scores. Though plasma apoA-V, PTA, total bilirubin(TBil) and blood urea nitrogen(BUN) were all independent factors to predict one-year outcomes of HBV-ACLF, plasma apoA-V had the highest prediction accuracy. And its optimal cutoff value for one-year survival prediction was 480.00 ng/mL, which had a positive predictive value of 84.68% and a negative predictive value of 92.23%. In summary, plasma apoA-V decreases significantly in non-survivors of HBV-ACLF, and it may be regarded as a new predictive marker for the prognosis of patients with HBV-ACLF. Show less

Familial adenomatous polyposis (FAP) is one of the most common hereditary colorectal cancers. Its intestinal and extra-intestinal manifestations are correlated with mutation sties of the APC gene. Potential gene modulation sites in patients who have typical clinical manifestations but with unidentified APC mutations are also discussed, which included MUTYH gene, AXIN gene and certain epigenetic changes. With the generalization of Precision Medicine, to offer individualized treatment and surveillance strategy based on the genotype-phenotype correlation will be of great value for FAP patients. This review focuses on the research advance in genotype - phenotype correlation studies of FAP patients. Show less

Hemangioblastomas (HBs) are uncommon tumors characterized by the presence of inactivating alterations in the von Hippel-Lindau (VHL) gene in inherited cases and by infrequent somatic mutation in sporadic entities. We performed whole exome sequencing on 11 HB patients to further elucidate the genetics of HBs. A total of 270 somatic variations in 219 genes, of which there were 86 mutations in 67 genes, were found in sporadic HBs, and 184 mutations were found in 154 genes in familial HBs. C: G>T: A and T: A>C: G mutations are relatively common in most HB patients. Genes harboring the most significant mutations include PCDH9, KLHL12, DCAF4L1, and VHL in sporadic HBs, and ZNF814, DLG2, RIMS1, PNN, and MUC7 in familial HBs. The frequency of CNV varied considerably within sporadic HBs but was relatively similar within familial HBs. Five genes, including OTOGL, PLCB4, SCEL, THSD4, and WWOX, have CNVs in the six patients with sporadic HBs, and three genes, including ABCA6, CWC27, and LAMA2, have CNVs in the five patients with familial HBs. We found new genetic mutations and CNVs that might be involved in HBs; these findings highlight the complexity of the tumorigenesis of HBs and pinpoint potential therapeutic targets for the treatment of HBs. Show less

To identify novel candidate genes and gene sets for diabetes. We performed an integrative analysis of genome-wide association studies (GWAS) and expression quantitative trait loci (eQTLs) data for diabetes. Summary data was driven from a large-scale GWAS of diabetes, totally involving 58,070 individuals. eQTLs dataset included 923,021 cis-eQTL for 14,329 genes and 4,732 trans-eQTL for 2,612 genes. Integrative analysis of GWAS and eQTLs data was conducted by summary data-based Mendelian randomization (SMR). To identify the gene sets associated with diabetes, the SMR single gene analysis results were further subjected to gene set enrichment analysis (GSEA). A total of 13,311 annotated gene sets were analyzed in this study. SMR analysis identified 6 genes significantly associated with fasting glucose, such as C11ORF10 ( Our study provides novel clues for clarifying the genetic mechanism of diabetes. This study also illustrated the good performance of SMR approach and extended it to gene set association analysis for complex diseases. Show less

Non-alcoholic fatty liver disease (NAFLD) and its causal factors of hepatic insulin resistance (IR) and type 2 diabetes are rapidly growing worldwide. Developing new therapeutic methods for these conditions requires a comprehensive understanding between hepatic lipid metabolism and IR. Sterol regulatory element-binding transcription factor 1c (SREBP-1c) and carbohydrate responsive-element binding protein (ChREBP) are the major regulators of fatty acid synthase (FASN), a key enzyme of de novo fatty acid synthesis. They are induced by insulin, which directly binds to the sterol regulatory elements (SRE) or carbohydrate-responsive elements (ChORE) of the FASN promoter to induce its expression. The insulin pathway involved in NAFLD has well studied, but the role of histone modification in NAFLD is just beginning to be investigated, and there is minimal data regarding its involvement. In the current study, we investigated histone modifications in FASN under insulin stimulation. H3K4 hypertrimethylation and H3, H4 hyperacetylation in the FASN promoter was found in HepG2 cells and primary hepatocytes following insulin stimulation. We also found that insulin treatment induced the transcription factor SREBP-1c, ChREBP and could accelerate FASN expression by enhancing SREBP-1c, SRE, and ChREBP ChORE binding and inducing H3, H4 hyperacetylation at SRE, ChORE, or transcription start site (TSS) regions of the FASN promoter in hepatocellular carcinoma cell line (HepG2) and primary hepatocytes. Finally, histone acetylation could influence FASN expression by impairing SREBP-1c SRE and ChREBP ChORE binding. Show less

Several nucleoporins in the nuclear pore complex (NPC) have been reported to be involved in abiotic stress responses in plants. However, the molecular mechanism of how NPC regulates abiotic stress responses, especially the expression of stress responsive genes remains poorly understood. From a forward genetics screen using an abiotic stress-responsive luciferase reporter (RD29A-LUC) in the sickle-1 (sic-1) mutant background, we identified a suppressor caused by a mutation in NUCLEOPORIN 85 (NUP85), which exhibited reduced expression of RD29A-LUC in response to ABA and salt stress. Consistently, the ABA and salinity induced expression of several stress responsive genes such as RD29A, COR15A and COR47 was significantly compromised in nup85 mutants and other nucleoporin mutants such as nup160 and hos1. Subsequently, Immunoprecipitation and mass spectrometry analysis revealed that NUP85 is potentially associated with HOS1 and other nucleoporins within the nup107-160 complex, along with several mediator subunits. We further showed that there is a direct physical interaction between MED18 and NUP85. Similar to NUP85 mutations, MED18 mutation was also found to attenuate expression of stress responsive genes. Taken together, we not only revealed the involvement of NUP85 and other nucleoporins in regulating ABA and salt stress responses, but also uncovered a potential relation between NPC and mediator complex in modulating the gene expression in plants. Show less

The GTPase Rab5 and phosphatidylinositol-3 phosphate [PI(3)P] coordinately regulate endosome trafficking. Rab5 recruits Vps34, the class III phosphoinositide 3-kinase (PI3K), to generate PI(3)P and recruit PI(3)P-binding proteins. Loss of Rab5 and loss of Vps34 have opposite effects on endosome size, suggesting that our understanding of how Rab5 and PI(3)P cooperate is incomplete. Here, we report a novel regulatory loop whereby Show less

Glucagon-like peptide-1 (GLP-1) receptor (GLP-1R), glucagon (GCG) receptor (GCGR), and glucose-dependent insulinotropic polypeptide (GIP, also known as gastric inhibitory polypeptide) receptor (GIPR), are three metabolically related peptide hormone receptors. A novel approach to the generation of multifunctional antibody agonists that activate these receptors has been developed. Native or engineered peptide agonists for GLP-1R, GCGR, and GIPR were fused to the N-terminus of the heavy chain or light chain of an antibody, either alone or in pairwise combinations. The fusion proteins have similar in vitro biological activities on the cognate receptors as the corresponding peptides, but circa 100-fold longer plasma half-lives. The GLP-1R mono agonist and GLP-1R/GCGR dual agonist antibodies both exhibit potent effects on glucose control and body weight reduction in mice, with the dual agonist antibody showing enhanced activity in the latter. Show less

The Goto-Kakizaki (GK) rat is an animal model of non-obese type 2 diabetes (T2D). The GK rat was generated through the introduction of various genetic mutations from continuous inbreeding; these rats develop diabetes spontaneously. The mutated genes in GK rats may play key roles in the regulation of diabetes. The hypothalamus plays a central role in systematic energy homeostasis. Here, the hypothalamic transcriptomes in GK and Wistar rats at 4, 8 and 12 weeks were investigated by RNA-seq, and multiple variants and gene expression profiles were obtained. The number of variants identified from GK rats was significantly greater than that of Wistar rats, indicating that many variants were fixed and heritable in GK rats after selective inbreeding. The differential gene expression analysis indicated that GK rats had a dysfunctional hypothalamic melanocortin system and attenuation of the hypothalamic glucose-sensing pathway. In addition, we generated integrated gene network modules by combining the protein-protein interaction (PPI) network, co-expression network and mutations in GK and Wistar rats. In the modules, GK-specific genes, such as Bad, Map2k2, Adcy3, Adcy2 and Gstm6, may play key roles in hypothalamic regulation in GK rats. Our research provides a comprehensive map of the abnormalities in the GK rat hypothalamus, which reveals the new mechanisms of pathogenesis of T2D. Show less

Hepatitis E virus- (HEV-) mediated hepatitis has become a global public health problem. An important regulatory protein of HEV, ORF3, influences multiple signal pathways in host cells. In this study, to investigate the function of ORF3 from the swine form of HEV (SHEV), high-throughput RNA-Seq-based screening was performed to identify the differentially expressed genes in ORF3-expressing HepG2 cells. The results were validated with quantitative real-time PCR and gene ontology was employed to assign differentially expressed genes to functional categories. The results indicated that, in the established ORF3-expressing HepG2 cells, the mRNA levels of CLDN6, YLPM1, APOC3, NLRP1, SCARA3, FGA, FGG, FGB, and FREM1 were upregulated, whereas the mRNA levels of SLC2A3, DKK1, BPIFB2, and PTGR1 were downregulated. The deregulated expression of CLDN6 and FREM1 might contribute to changes in integral membrane protein and basement membrane protein expression, expression changes for NLRP1 might affect the apoptosis of HepG2 cells, and the altered expression of APOC3, SCARA3, and DKK1 may affect lipid metabolism in HepG2 cells. In conclusion, ORF3 plays a functional role in virus-cell interactions by affecting the expression of integral membrane protein and basement membrane proteins and by altering the process of apoptosis and lipid metabolism in host cells. These findings provide important insight into the pathogenic mechanism of HEV. Show less

Wnt signaling components have been shown to control key events in embryogenesis and to maintain tissue homeostasis in the adult. Nkd1/2 and Axin1/2 protein families are required for feedback regulation of Wnt signaling. The mechanisms by which Nkd1 and Nkd2 exhibit significant differences in signal transduction remain incompletely understood. Here we report that Rnf25/AO7, a previously identified E3 ubiquitin ligase for Nkd2, physically interacts with Nkd1 and Axin in an E3 ligase-independent manner to strengthen Wnt signalling. To determine the biological role of Rnf25 in vivo, we found that the renal mesenchymal cell, in which rnf25 was knocked-down, also exhibited more epithelial characters than MOCK control. Meanwhile, the transcriptional level of rnf25 was elevated in three separate tumor tissues more than that in paracarcinomatous tissue. Depletion of Rnf25 in zebrafish embryos attenuated transcriptions of maternal and zygotic Wnt target genes. Our results indicated that Rnf25 might serve as a molecular device, controlling the different antagonizing functions against canonical Wnt signaling between Nkd1 and Nkd2 cooperated with Axin. Show less

Dyslipidemia is common in polycystic ovary syndrome (PCOS). This study was aimed to investigate whether fatty acid desaturase genes (FADS), a dyslipidemia-related gene cluster, are associated with PCOS. We scanned variations of FADS genes using our previous data of genome-wide association study (GWAS) for PCOS and selected rs174570 for further study. The case-control study was conducted in an independent cohort of 1918 PCOS cases and 1889 age-matched controls and family-based study was conducted in a set of 243 core family trios with PCOS probands. Minor allele frequency (allele T) of rs174570 was significantly lower in PCOS cases than that in age-matched controls (P = 2.17E-03, OR = 0.85), even after adjustment of BMI and age. PCOS subjects carrying CC genotype had higher testosterone level and similar lipid/glucose level compared with those carrying TT or TC genotype. In trios, transmission disequilibrium test (TDT) analysis revealed risk allele C of rs174570 was significantly over-transmitted (P = 2.00E-04). Decreased expression of FADS2 was detected in PCOS cases and expression quantitative trait loci (eQTL) analysis revealed the risk allele C dosage was correlated with the decline of FADS2 expression (P = 0.002). Our results demonstrate that FADS1-FADS2 are susceptibility genes for PCOS. Show less

The class III phosphoinositide 3-kinase (PI3K) Vps34 (also known as PIK3C3 in mammals) produces phosphatidylinositol 3-phosphate [PI(3)P] on both early and late endosome membranes to control membrane dynamics. We used Vps34-deficient cells to delineate whether Vps34 has additional roles in endocytic trafficking. In Vps34 Show less

Commercial sheep raised for mutton grow faster than traditional Chinese sheep breeds. Here, we aimed to evaluate genetic selection among three different types of sheep breed: two well-known commercial mutton breeds and one indigenous Chinese breed. We first combined locus-specific branch lengths and di statistical methods to detect candidate regions targeted by selection in the three different populations. The results showed that the genetic distances reached at least medium divergence for each pairwise combination. We found these two methods were highly correlated, and identified many growth-related candidate genes undergoing artificial selection. For production traits, APOBR and FTO are associated with body mass index. For meat traits, ALDOA, STK32B and FAM190A are related to marbling. For reproduction traits, CCNB2 and SLC8A3 affect oocyte development. We also found two well-known genes, GHR (which affects meat production and quality) and EDAR (associated with hair thickness) were associated with German mutton merino sheep. Furthermore, four genes (POL, RPL7, MSL1 and SHISA9) were associated with pre-weaning gain in our previous genome-wide association study. Our results indicated that combine locus-specific branch lengths and di statistical approaches can reduce the searching ranges for specific selection. And we got many credible candidate genes which not only confirm the results of previous reports, but also provide a suite of novel candidate genes in defined breeds to guide hybridization breeding. Show less

To explore the role of CD44 in monocyte adhesion to human brain microvascular endothelial cells (HBMECs) and monocyte migration across an in vitro model of blood-brain barrier (BBB) infected by Cryptococcus neoformans (Cn). An in vitro blood-brain barrier model was constructed using a transwell chamber covered with a HBMEC monolayer. The wild-type strain of Cn B4500FO2, TYCC645#32 strain with CPS1 gene deletion and PCIP strain with CPS1 complementation were chosen to infect the monolayer HBMECs. THP-1 cells were added to the upper chamber of transwell, and the relative migration rate was determined by counting the number of the cells entering the lower chambers. The inhibitory effects of anti-CD44 monoclonal antibody and the CD44 inhibitor bikunin were examined on THP-1 binding to and migration across HBMECs. Cn infection of the HBMECs caused markedly enhanced THP-1 cell adhesion and migration across the monolyers (P<0.01) dependent on Cn concentration and exposure time. Addition of anti-CD44 monoclonal antibody and bikunin significantly lowered THP-1 adhesion and migration rates in the BBB model with Cn-infected HBMECs (P<0.01) with a dose dependence of the antibody (within 0-1 µg) and inhibitor (within 0-20 nmol/L). Both THP-1 adhesion rate and migration rate were lowered in the BBB model infected with CPS1 gene-deleted Cn but increased in the model infected with the complemented strain compared with those in the wild-type strain-infected model. In the in vitro BBB model, CD44 expressed on HBMECs may play an essential role in monocyte adhesion to and migration across the BBB. The capsular hyaluronic acid may mediate Cn-induced monocyte adhesion and migration. Show less