👤 Pengxiang Ji

Currently, brown adipose tissue (BAT) is a therapeutic target in obesity and diabetes, but the mechanism of BAT activation remains unclear. Because increasing emphasis has been placed on the role of intracellular peptides in biological processes, we conducted a study to gain insight into the mechanism of BAT activation by using a peptidomic approach and then attempted to identify peptides that are capable of activating BAT. In the present study, we generated the peptidomic profile of the intracellular peptides in brown adipocytes treated with forskolin (FSK) using a peptidomic approach. Then, the differentially expressed peptides were evaluated via Gene Ontology (GO) enrichment, KEGG pathway, and protein-protein interaction (PPI) network analysis. Finally, we selected candidate peptides for further validation via assessing the expression levels of UCP-1 and PGC-1α in brown adipocytes exposed to the peptides. A total of 4,370 peptides were identified, of which 951 were upregulated and 379 were downregulated after FSK treatment. Bioinformatic analysis demonstrated that the ECM-receptor interaction GO term was the most enriched and that collagen alpha-related proteins exhibited the highest degree of PPI. Four peptides separately derived from TSC22 domain family protein 1 (T22D1), bromodomain and WD repeat-containing protein 1 (BRWD1), protein piccolo (PCLO), and collagen alpha-1 (III) chain (CO3A1) increased the expression levels of UCP-1 and PGC-1α. ECM-receptor interaction may play an important role in the process of FSK-stimulated BAT activation, and the pT22D1tide, pBRWD1tide, pPCLOtide, and pCO3A1tide peptides potentially promote BAT thermogenesis. Show less

Determine the impact of CETP (cholesteryl ester transfer protein) on the route of cholesterol elimination in mice. Approach and Results: We adapted our protocol for biliary cholesterol secretion with published methods for measuring transintestinal cholesterol elimination. Bile was diverted and biliary lipid secretion maintained by infusion of bile acid. The proximal small bowel was perfused with bile acid micelles. In high-fat, high-cholesterol-fed mice, the presence of a CETP transgene increased biliary cholesterol secretion at the expense of transintestinal cholesterol elimination. The increase in biliary cholesterol secretion was not associated with increases in hepatic SR-BI (scavenger receptor BI) or ABCG5 (ATP-binding cassette G5) ABCG8. The decline in intestinal cholesterol secretion was associated with an increase in intestinal Niemann-Pick disease, type C1, gene-like 1 mRNA. Finally, we followed the delivery of HDL (high-density lipoprotein) or LDL (low-density lipoprotein) cholesteryl esters (CE) from plasma to bile and intestinal perfusates. HDL-CE favored the biliary pathway. Following high-fat feeding, the presence of CETP directed HDL-CE away from the bile and towards the intestine. The presence of CETP increased LDL-CE delivery to bile, whereas the appearance of LDL-CE in intestinal perfusate was near the lower limit of detection. Biliary and intestinal cholesterol secretion can be simultaneously measured in mice and used as a model to examine factors that alter cholesterol elimination. Plasma factors, such as CETP, alter the route of cholesterol elimination from the body. Intestinal and biliary cholesterol secretion rates are independent of transhepatic or transintestinal delivery of HDL-CE, whereas LDL-CE was eliminated almost exclusively in the hepatobiliary pathway. Show less

Various cancer stem cell (CSC) biomarkers have been identified for hepatocellular carcinoma (HCC), but little is known about the implications of heterogeneity and shared molecular networks within the CSC population. Through miRNA profile analysis in an HCC cohort ( Show less

Glaucoma is characterized by progressive, irreversible damage to the retinal ganglion cells (RGCs) and their axons. Our previous study has shown that the intravitreal transplantation of human umbilical cord mesenchymal stem cells (hUC-MSCs) reveals a neuroprotective role in microsphere injection-induced ocular hypertension (OHT) rat models. The protection is related to the modulation of glial cells, but the mechanisms are still unknown. The purpose of the present study is to clarify the potential neuroinflammatory mechanisms involved in the neuroprotective role of hUC-MSCs. OHT models were established with SD rats through intracameral injection of polystyrene microbeads. The animals were randomly divided into three groups: the normal group, the OHT+phosphate-buffered saline (PBS) group, and the OHT+hUC-MSC group. Retinal morphology was evaluated by measuring the inner retinal thickness via optical coherence tomography (OCT). Retinal cell apoptosis was examined by TUNEL staining and Bax expression 14 days following hUC-MSC transplantation. The expression levels of glial fibrillary acidic protein (GFAP), ionized calcium binding adapter molecule 1 (iba-1), and toll-like receptor 4 (TLR4) were assessed via immunohistochemistry, real-time quantitative PCR, and Western blot. RNA and proteins were extracted 14 days following transplantation, and the expression levels of the TLR4 signaling pathways and proinflammatory cytokines-myeloid differentiation factor 88 (MyD88), IL-1 Show less

Objective To investigate the expression of semaphorin 6D (SEMA6D) and Snail and their clinicopathological implications in gastric cancer. Methods 54 cases of gastric cancer tissues and 26 paracancerous gastric mucosa were collected for detecting the expression of SEMA6D and Snail by immunohistochemistry and Western blot analysis. The co-localization of SEMA6D and Snail was observed by immunofluorescence double staining and laser scanning confocal microscopy. The correlation between SEMA6D and Snail and their relationships with the clinicopathological features of the patients were analyzed. Results Compared with the paracancerous gastric mucosa, the protein expression of SEMA6D and Snail in the gastric cancer significantly increased, and there was a significant co-localization of SEMA6D and Snail in gastric cancer. Further statistical analysis showed that the expression of SEMA6D and Snail in gastric cancer was positively correlated with the degree of differentiation, invasion, lymph node metastasis and TNM stage. Conclusion The high expression of SEMA6D and Snail in gastric cancer are related to the malignant clinicopathological indexes of gastric cancer. Show less

Phosphatase and tensin homolog (PTEN), one of the most frequently mutated tumor suppressor genes in human cancer, is pivotal in the progression of colorectal cancer. Therefore, the regulation of PTEN has emerged as a theme of intense research in tumor biology. This study aims to show that long noncoding RNA (lncRNA) Linc02023 aberrant downregulation in colorectal cancer correlates positively with the expression of PTEN and CDKN2B but negatively with the tumor size in patients and xenografted mouse models. The gain- and loss-of-function investigation reveals that Linc02023 suppresses the proliferation of colorectal cancer cells in vitro and in vivo with apoptosis promotion and cell cycle rearrangement. Mechanistically, Linc02023 specifically binds to PTEN and blocks its interaction with and ubiquitination by WWP2, stabilizing it and suppressing its downstream expression. In conclusion, this study demonstrates that lncRNA Linc02023 may serve as a novel therapeutic target by restoring the PTEN tumor suppressor activity. Show less

Epithelial ovarian cancer (EOC) is the fifth leading cause of cancer mortality in American women. Normal ovarian physiology is intricately connected to small GTP binding proteins of the Ras superfamily (Ras, Rho, Rab, Arf, and Ran) which govern processes such as signal transduction, cell proliferation, cell motility, and vesicle transport. We hypothesized that common germline variation in genes encoding small GTPases is associated with EOC risk. We investigated 322 variants in 88 small GTPase genes in germline DNA of 18,736 EOC patients and 26,138 controls of European ancestry using a custom genotype array and logistic regression fitting log-additive models. Functional annotation was used to identify biofeatures and expression quantitative trait loci that intersect with risk variants. One variant, ARHGEF10L (Rho guanine nucleotide exchange factor 10 like) rs2256787, was associated with increased endometrioid EOC risk (OR = 1.33, p = 4.46 x 10-6). Other variants of interest included another in ARHGEF10L, rs10788679, which was associated with invasive serous EOC risk (OR = 1.07, p = 0.00026) and two variants in AKAP6 (A-kinase anchoring protein 6) which were associated with risk of invasive EOC (rs1955513, OR = 0.90, p = 0.00033; rs927062, OR = 0.94, p = 0.00059). Functional annotation revealed that the two ARHGEF10L variants were located in super-enhancer regions and that AKAP6 rs927062 was associated with expression of GTPase gene ARHGAP5 (Rho GTPase activating protein 5). Inherited variants in ARHGEF10L and AKAP6, with potential transcriptional regulatory function and association with EOC risk, warrant investigation in independent EOC study populations. Show less

Cholangiocarcinoma (CCA) is the most common biliary tract malignancy, with a low survival rate and limited treatment options. Long non-coding RNAs (lncRNAs) have recently been verified to have significant regulatory functions in many kinds of human cancers. It was discovered in this study that the lncRNA PVT1, whose expression is significantly elevated in CCA, could be a molecular marker of CCA. Experiments indicated that PVT1 knockdown greatly inhibited cell migration and proliferation in vitro and in vivo. According to RNA sequencing (RNA-seq) analysis, PVT1 knockdown dramatically influenced target genes associated with cell angiogenesis, cell proliferation, and the apoptotic process. RNA immunoprecipitation (RIP) analysis demonstrated that, by binding to epigenetic modification complexes (PRC2), PVT1 could adjust the histone methylation of the promoter of ANGPTL4 (angiopoietin-like 4) and, thus, promote cell growth, migration, and apoptosis progression. The data verified the significant functions of PVT1 in CCA oncogenesis, and they suggested that PVT1 could be a target for CCA intervention. Show less

Over the past decades, the epidemic of childhood obesity has greatly increased, and it has recently become a global public health concern. Methylation, serving as a crucial regulator of the gene-environment interaction, has exhibited a strong association with obesity. In this study, we aimed to evaluate the relationship between DNA methylation and childhood obesity, and further uncover the potential association of aberrantly methylated genes with obesity. DNA samples of peripheral blood leukocytes from three obese subjects (mean BMI: 21.67) and 4 age/sex matched controls (mean BMI: 14.92) were subjected to Infinium Human Methylation 450 Bead Array analysis. A total of more than 4 85 000 methylation sites were identified across the genome, and 226 methylated CpGs (DMCpGs) were differentially methylated between these two groups. Subsequent Gene Ontology (GO) and KEGG Pathway analyses showed that these DMCpGs were mainly engaged in immunity and lipoprotein metabolism, indicating their physiological significance. Further verification of the candidate CpG sites within the HDAC4, RAX2, APOA5, CES1, and SLC25A20 gene loci, were performed using bisulfite sequencing PCR (BSP) in a cohort of 42 controls and 39 obese cases. The results revealed that methylation levels within HDAC4 and RAX2 loci were positively associated with obesity, while the methylation levels of loci within APOA5 and CES1 loci were negatively correlated with obesity. Thus, alterations in methylation of CpG sites of specific genes may contribute to childhood obesity, which provide novel insights into the aetiology of obesity. Show less

Plants are frequently subjected to abiotic and biotic stresses, and WRKY proteins play a pivotal role in the response to such stress. OsWRKY11 is induced by pathogens, drought, and heat, suggesting a function in biotic and abiotic stress responses. This study identified OsWRKY11, a member of WRKY group IIc. It is a transcriptional activator that localized to the nucleus. Ectopic expression of OsWRKY11 resulted in enhanced resistance to a bacterial pathogen, Xanthomonas oryzae pv. oryzae; resistance was compromised in transgenic lines under-expressing OsWRKY11. Ectopic expression of OsWRKY11 resulted in constitutive expression of defense-associated genes, whereas knock-down (kd) of OsWRKY11 reduced expression of defense-associated genes during pathogen attack, suggesting that OsWRKY11 activates defense responses. OsWRKY11 bound directly to the promoter of CHITINASE 2, a gene associated with defense, and activated its transcription. In addition, ectopic expression of OsWRKY11 enhanced tolerance to drought stress and induced constitutive expression of drought-responsive genes. Induction of drought-responsive genes was compromised in OsWRKY11-kd plants. OsWRKY11 also bound directly to the promoter of a drought-responsive gene, RAB21, activating its transcription. In addition, OsWRKY11 protein levels were controlled by the ubiquitin-proteasome system. OsWRKY11 integrates plant responses to pathogens and abiotic stresses by positively modulating the expression of biotic and abiotic stress-related genes. Show less

A recent large-scale European-originated genome-wide association data meta-analysis followed by a replication study identified 6 new risk loci for Parkinson's disease (PD), which include rs10797576/SIPA1L2, rs117896735/INPP5F, rs329648/MIR4697, rs11158026/GCH1, rs2414739/VPS13C, and rs8118008/DDRGK1. However, whether these new loci are associated with PD in Asian populations remain elusive. The INPP5F is nonpolymorphic in Asians. The present study aimed to understand the effects of the other 5 new loci in a Han Chinese population comprising 579 sporadic PD patients and 642 controls. Significant associations with PD were observed in the variants of SIPA1L2 (p = 0.001) and VPS13C (p = 0.007), where the T (odd ratio [OR] = 1.484, 95% confidence interval [CI] 1.186-1.858) and A (OR = 1.362, 95% CI 1.087-1.707) alleles serve as the risk alleles, respectively. The genotype distributions in the SIPA1L2 and VPS13C variants were also different between the patients and controls (p = 0.002 and p = 0.023, respectively). In contrast, no significant association with PD was found in the variants of MIR4697, GCH1, and DDRGK1 either in allele or genotype frequencies. Noteworthy, a followed meta-analysis of East Asian studies suggested an association of the GCH1 variant with PD (p = 0.04, OR 1.08, 95% CI 1.00-1.16), while the other results are in line with those of our cohort. In conclusion, our study together with meta-analyses demonstrates that the variants of SIPA1L2 and VPS13C, potentially GCH1, but not of MIR4697 and DDRGK1, are associated with PD susceptibility in East Asians. Show less

Coronary heart disease (CHD) is the most common cause of death worldwide. This study aimed to validate the association of the rs964184 polymorphism with the CHD risk and included 874 CHD patients and 776 controls. rs964184 polymorphism genotyping was performed using Tm-shift polymerase chain reaction. A strong association of the rs964184 polymorphism with CHD was found (genotype: X Our results indicate that both gender and age have great impacts on the association of the rs964184 polymorphism with CHD among Chinese. Show less

The dysregulation of long noncoding RNAs (lncRNAs) has been identified in a variety of cancers. An increasing number of studies have found the critical role of lncRNAs in the regulation of cellular processes, such as proliferation, invasion and differentiation. Long noncoding RNA papillary thyroid carcinoma susceptibility candidate 3 (PTCSC3) is a novel lncRNA that was primarily detected in papillary thyroid carcinoma. However, the biological function and molecular mechanism of lncRNA PTCSC3 in glioma are still unknown. The expression level of lncRNA PTCSC3 in human microglia and glioma cell lines was examined using quantitative real-time polymerase chain reaction (qRT-PCR). The influence of lncRNA PTCSC3 on cell proliferation were studied using the cell counting kit-8, and cell cycle and apoptosis were analyzed by flow cytometry assays. The migration and invasion abilities were investigated by transwell and wound healing assays. The target genes of lncRNA PTCSC3 were explored by qRT-PCR, immunofluorescence and western blot. LncRNA PTCSC3 was significantly downregulated in glioma cell lines. The overexpression of lncRNA PTCSC3 suppressed proliferation and induced apoptosis in U87 and U251 cells. Additionally, the overexpression of lncRNA PTCSC3 inhibited the migration and invasion of U87 and U251 cells. Moreover, lncRNA PTCSC3 inhibited the epithelial-mesenchymal transition of U87 cells. The study also demonstrated that LRP6, as a receptor of the Wnt/β-catenin pathway, was a target of lncRNA PTCSC3. By evaluating the expression levels of Axin1, active β-catenin, c-myc, and cyclin D1, the study indicated that lncRNA PTCSC3 inhibited the activation of the Wnt/β-cateninpathway through targeting LRP6. LncRNA PTCSC3 inhibits the proliferation and migration of glioma cells and suppresses Wnt/β-catenin signaling pathway by targeting LRP6. LncRNA PTCSC3 is a potential therapeutic target for treatment of glioma. Show less

Uterine leiomyosarcoma (ULMS) is an aggressive form of soft tissue tumors. The molecular heterogeneity and pathogenesis of ULMS are not well understood. Expression profiling data were used to determine the possibility and optimal number of ULMS molecular subtypes. Next, clinicopathological characters and molecular pathways were analyzed in each subtype to prospect the clinical applications and progression mechanisms of ULMS. Two distinct molecular subtypes of ULMS were defined based on different gene expression signatures. Subtype I ULMS recapitulated low-grade ULMS, the gene expression pattern of which resembled normal smooth muscle cells, characterized by overexpression of smooth muscle function genes such as LMOD1, SLMAP, MYLK, MYH11. In contrast, subtype II ULMS recapitulated high-grade ULMS with higher tumor weight and invasion rate, and was characterized by overexpression of genes involved in the pathway of epithelial to mesenchymal transition and tumorigenesis, such as CDK6, MAPK13 and HOXA1. We identified two distinct molecular subtypes of ULMS responding differently to chemotherapy treatment. Our findings provide a better understanding of ULMS intrinsic molecular subtypes, and will potentially facilitate the development of subtype-specific diagnosis biomarkers and therapy strategies for these tumors. Show less

Neuregulin1β (NRG1β), a member of the excitomotor of tyrosine kinase receptor (erbB) family, was recently shown to play a neuroprotective role in cerebral ischemia-reperfusion injury. The present study analyzed the effects and its possible signaling pathway of NRG1β on brain tissues after cerebral ischemia-reperfusion injury. A focal cerebral ischemic model was established by inserting a monofilament thread to achieve middle cerebral artery occlusion, followed by an NRG1β injection via the internal carotid artery. NRG1β injection resulted in significantly improved neurobehavioral activity according to the modified neurological severity score test. Tetrazolium chloridestaining revealed a smaller cerebral infarction volume; hematoxylin-eosin staining and transmission electron microscopy showed significantly alleviated neurodegeneration in the middle cerebral artery occlusion rats. Moreover, expression of phosphorylated MEK5, phosphorylated ERK5, and phosphorylated MEK2C increased after NRG1β treatment, and the neuroprotective effect of NRG1β was attenuated by an injection of the MEK5 inhibitor, BIX02189. Results from the present study demonstrate that NRG1β provides neuroprotection following cerebral ischemia-reperfusion injury via the ERK5-dependent MAPK pathway. Show less

Alzheimer's disease (AD) represents the major form of dementia in the elderly. In recent years, accumulating evidence indicate that obesity may act as a risk factor for AD, while the genetic link between the two conditions remains unclear. This bioinformatics analysis aimed to detect the genetic link between AD and obesity on single nucleotide polymorphisms (SNPs), gene, and pathway levels based on genome-wide association studies data. A total of 31 SNPs were found to be shared by AD and obesity, which were linked to 7 genes. These genes included PSMC3, CELF1, MYBPC3, SPI1, APOE, MTCH2 and RAPSN. Further functional enrichment analysis of these genes revealed the following biological pathways, including proteasome, osteoclast differentiation, hypertrophic cardiomyopathy, dilated cardiomyopathy, Epstein-Barr virus and TLV-I infection, as well as several cancer associated pathways, to be common among AD and obesity. The findings deepened our understanding on the genetic basis linking obesity and AD and may help shape possible prevention and treatment strategies. Show less

Genome editing has potential for the targeted correction of germline mutations. Here we describe the correction of the heterozygous MYBPC3 mutation in human preimplantation embryos with precise CRISPR-Cas9-based targeting accuracy and high homology-directed repair efficiency by activating an endogenous, germline-specific DNA repair response. Induced double-strand breaks (DSBs) at the mutant paternal allele were predominantly repaired using the homologous wild-type maternal gene instead of a synthetic DNA template. By modulating the cell cycle stage at which the DSB was induced, we were able to avoid mosaicism in cleaving embryos and achieve a high yield of homozygous embryos carrying the wild-type MYBPC3 gene without evidence of off-target mutations. The efficiency, accuracy and safety of the approach presented suggest that it has potential to be used for the correction of heritable mutations in human embryos by complementing preimplantation genetic diagnosis. However, much remains to be considered before clinical applications, including the reproducibility of the technique with other heterozygous mutations. Show less

Gliomas are commonly malignant tumors that arise in the human central nervous system and have a low overall five-year survival rate. Previous studies reported that several members of Rab GTPase family are involved in the development of glioma, and abnormal expression of Rab small GTPases is known to cause aberrant tumor cell behavior. In this study, we characterized the roles of Rab21 (Rab GTPase 21), a member of Rab GTPase family, in glioma cells. The study involved downregulation of Rab21 in two glioma cell lines (T98G and U87) through transfection with specific-siRNA. Experiments using the MTT assay, cell cycle analysis, apoptosis assay, real-time PCR and western blot were performed to establish the expression levels of related genes. The results show that downregulation of Rab21 can significantly inhibit cell growth and remarkably induce cell apoptosis in T98G and U87 cell lines. Silencing Rab21 resulted in significantly increased expression of apoptosis-related proteins (caspase7, Bim and Bax) in glioma cells. We inferred that Rab21 silencing can induce apoptosis and inhibit proliferation in human glioma cells, indicating that Rab21 might act as an oncogene and serve as a novel target for glioma therapy. Show less

Schizophrenia is a severe mental disorder that is likely to be strongly determined by genetic factors. To identify markers of disks, large homolog 2 (DLG2), FAT atypical cadherin 3 (FAT3), kinectin1 (KTN1), deleted in colorectal carcinoma (DCC), and glycogen synthase kinase-3β (GSK3β) that contribute to the genetic susceptibility to schizophrenia, we systematically screened for polymorphisms in the functional regions of these genes. A total of 22 functional single-nucleotide polymorphisms (SNPs) in 940 Chinese subjects were genotyped using SNaPshot. The results first suggested that the allelic and genotypic frequencies of the DCC polymorphism rs2229080 were nominally associated with schizophrenia. The patients were significantly less likely to be CC homozygous (P = 0.005, odds ratio [OR] = 0.635, 95 % confidence interval [95 % CI] = 0.462-0.873), and the schizophrenia subjects exhibited lower frequency of the C allele (P = 0.024, OR = 0.811, 95 % CI = 0.676-0.972). Regarding GSK3β, there was a significant difference in genotype distribution of rs3755557 between schizophrenia and healthy control subjects (P = 0.009). The patients exhibited a significantly lower frequency of the T allele of rs3755557 (P = 0.002, OR = 0.654, 95 % CI = 0.498-0.860). Our results point to the polymorphisms of DCC and GSK3β as contributors to the genetic basis of individual differences in the susceptibility to schizophrenia. Show less

It is generally recognized that the inflammatory reaction in glia is one of the important pathological factors in brain ischemic injury. Our previous study has revealed that opening ATP-sensitive potassium (K-ATP) channels could attenuate glial inflammation induced by ischemic stroke. However, the detailed mechanisms are not well known. Primary cultured astrocytes separated from C57BL/6 mice were subjected to oxygen-glucose deprivation (OGD); cellular injuries were determined via observing the changes of cellular morphology and cell viability. MicroRNA (miR) and messenger RNA (mRNA) level was validated by real-time PCR. The interaction between microRNA and the target was confirmed via dual luciferase reporter gene assay. Expressions of proteins and inflammatory cytokines were respectively assessed by western blotting and enzyme-linked immunosorbent assay. OGD resulted in astrocytic damage, which was prevented by K-ATP channel opener nicorandil. Notably, we found that OGD significantly downregulated miR-7 and upregulated Herpud2. Our further study proved that miR-7 targeted Herpud2 3'UTR, which encoded endoplasmic reticulum (ER) stress protein-HERP2. Correspondingly, our results showed that OGD increased the levels of ER stress proteins along with significant elevations of pro-inflammatory cytokines, including tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β). Pretreatment with nicorandil could remarkably upregulate miR-7, depress the ER-related protein expressions including glucose-regulated protein 78 (GRP78), C/EBP-homologous protein (CHOP), and Caspase-12, and thereby attenuate inflammatory responses and astrocytic damages. These findings demonstrate that opening K-ATP channels protects astrocytes against OGD-mediated neuroinflammation. Potentially, miR-7-targeted ER stress acts as a key molecular brake on neuroinflammation. Show less

Hyperammonemia is frequently seen in tumor microenvironments as well as in liver diseases where it can lead to severe brain damage or death. Ammonia induces autophagy, a mechanism that tumor cells may use to protect themselves from external stresses. However, how cells sense ammonia has been unclear. Here we show that culture medium alone containing Glutamine can generate milimolar of ammonia at 37 degrees in the absence of cells. In addition, we reveal that ammonia acts through the G protein-coupled receptor DRD3 (Dopamine receptor D3) to induce autophagy. At the same time, ammonia induces DRD3 degradation, which involves PIK3C3/VPS34-dependent pathways. Ammonia inhibits MTOR (mechanistic target of Rapamycin) activity and localization in cells, which is mediated by DRD3. Therefore, ammonia has dual roles in autophagy: one to induce autophagy through DRD3 and MTOR, the other to increase autophagosomal pH to inhibit autophagic flux. Our study not only adds a new sensing and output pathway for DRD3 that bridges ammonia sensing and autophagy induction, but also provides potential mechanisms for the clinical consequences of hyperammonemia in brain damage, neurodegenerative diseases and tumors. Show less

We have previously shown that the nuclear receptor, NR1D1, is a cofactor in ApoA-IV-mediated downregulation of gluconeogenesis. Nuclear receptor, NR4A1, is involved in the transcriptional regulation of various genes involved in inflammation, apoptosis, and glucose metabolism. We investigated whether NR4A1 influences the effect of ApoA-IV on hepatic glucose metabolism. Our in situ proximity ligation assays and coimmunoprecipitation experiments indicated that ApoA-IV colocalized with NR4A1 in human liver (HepG2) and kidney (HEK-293) cell lines. The chromatin immunoprecipitation experiments and luciferase reporter assays indicated that the ApoA-IV and NR4A1 colocalized at the RORα response element of the human G6Pase promoter, reducing its transcriptional activity. Our RNA interference experiments showed that knocking down the expression of NR4A1 in primary mouse hepatocytes treated with ApoA-IV increased the expression of NR1D1, G6Pase, and PEPCK, and that knocking down NR1D1 expression increased the level of NR4A1. We also found that ApoA-IV induced the expression of endogenous NR4A1 in both cultured primary mouse hepatocytes and in the mouse liver, and decreased glucose production in primary mouse hepatocytes. Our findings showed that ApoA-IV colocalizes with NR4A1, which suppresses G6Pase and PEPCK gene expression at the transcriptional level, reducing hepatic glucose output and lowering blood glucose. The ApoA-IV-induced increase in NR4A1 expression in hepatocytes mediates further repression of gluconeogenesis. Our findings suggest that NR1D1 and NR4A1 serve similar or complementary functions in the ApoA-IV-mediated regulation of gluconeogenesis. Show less

Apolipoprotein A-IV (apoA-IV) is a protein mainly synthesized by enterocytes in the intestine. Its gene expression is suppressed during fasting and stimulated during active fat absorption. Chronic feeding of a high-fat (HF) diet abolishes the differential expression between fasting and fat-feeding and therefore may contribute to diet-induced obesity since apoA-IV is a potent satiety factor. It is well established that the circulating pro-inflammatory cytokines TNF-α and IL-6 are increased by HF feeding. To determine whether pro-inflammatory cytokines are involved in the diminished response of apoA-IV gene expression to fat-feeding, different concentrations of linoleic acid (LA), an important dietary fatty acid, was used to stimulate apoA-IV expression in human intestinal Caco2 cells. Cells were pre-treated with or without human recombinant TNF-α, IL-6 or their combination before the addition of LA. Real-time PCR and ELISA were used to detect and quantify RNA transcripts and proteins of apoA-IV and the cytokines. LA stimulated gene and protein expression of apoA-IV in a dose and time dependent manner. Pre-treatment with the cytokines for 72 h significantly inhibited the increased expression of apoA-IV gene and protein induced by LA. Furthermore, the cytokines, especially TNF-α, also positively up-regulate the cytokine themselves in Caco2 cells. Our data indicate that the pro-inflammatory cytokines may be responsible for the reduced apoA-IV production in response to fat feeding. Because of apoA-IV's role in satiety, we propose the inhibitory effect of circulating pro-inflammatory cytokines on apoA-IV production contributes to diet-induced obesity. Show less

Overexpression of 5-hydroxytryptamine (5-HT) in human cancer contributes to tumor metastasis, but the role of 5-HT receptor family in cancer has not been thoroughly explored. Here, we report overexpression of 5-HT(1D) receptor (5-HT(1D)R) was associated with Wnt signaling pathway and advanced tumor stage. The underlying mechanism of 5-HT(1D)R-promoted tumor invasion was through its activation on the Axin1/β-catenin/MMP-7 pathway. In an orthotopic colorectal cancer mouse model, we demonstrated that a 5-HT(1D)R antagonist (GR127935) effectively inhibited tumor metastasis through targeting Axin1. Furthermore, in intestinal epithelium cells, we observed that 5-HT(1D)R played an important role in cell invasion via Axin1/β-catenin/MMP-7 pathway. Together, our findings reveal an essential role of the physiologic level of 5-HT(1D)R in pulmonary metastasis of colorectal cancer. Show less

The aim of the study was to explore the effect of PSD-93 deficiency on the expression of early inflammatory cytokines induced by cerebral ischemia/reperfusion injury. Ten- to twelve-week-old male PSD-93 knockout (PSD-93 KO) mice (C57BL/6 genetic background) and wild-type (WT) littermates were randomly divided into sham and ischemia/reperfusion (I/R) group. The focal cerebral I/R model was established by middle cerebral artery occlusion (MCAO) suture method. RT-PCR was used to detect the mRNA expression of IL-6, IL-10, Cox-2, iNOS, and TNF-α4h following reperfusion. Infarct volume at different time points after I/R was analyzed using 2,3,5-triphenyl tetrazolium staining, and neurological damage score (neurological severity scores, NSS) was used to evaluate the effect of PSD-93 gene knockout on the MCAO-induced neurological injury. In WT mice, early I/R injury led to the increase in the mRNA expression of proinflammatory cytokines IL-6, Cox-2, iNOS, and TNF-α that coincided with the decrease in the expression of anti-inflammatory cytokine IL-10, as compared to the sham group (P < 0.05). This effect was markedly attenuated by depleting PSD-93 levels by gene knockout. As compared to sham group, in PSD-93 KO mice I/R4h led to downregulation of Cox-2 and iNOS expression, and increase in the mRNA levels of IL-10 (P < 0.05). In addition, following MCAO, PSD-93 KO mice exhibited improved NSS and reduced infarct volumes, as compared with WT animals. PSD-93 knockout may play a neuroprotective role by mediating the early release of inflammatory cytokines induced by cerebral ischemia. Show less

Previous studies reported that miR-1908 was highly expressed in mature human adipocytes. Adipokines tumor necrosis factor α (TNF-α) that was known to activate NF-kappaB signaling could affect the expression of miR-1908 in adipocytes. However, little is known about the underlying mechanisms. In this study, we identified miR-1908 promoter using polymerase chain reaction (PCR) from human genomic DNA. Bioinformatic analysis was applied to predict the NF-kappaB binding sites in miR-1908 promoter. Real-time PCR, dual luciferase reporter assay, Mutagenesis analysis and electrophoretic mobility shift assay (EMSA) were performed to demonstrate the function of NF-kappaB binding sites in miR-1908 promoter. 1243bp miR-1908 promoter located in the intron of host gene fatty acid desaturase 1 (FADS1). Bioinformatic analysis revealed the presence of two putative NF-kappaB binding sites. TNF-α restricts miR-1908 expression in preadipocytes, and TNF-α decreases miR-1908 promoter activity in HEK293T cells. In addition, those two NF-kappaB transcription factor binding sites in miR-1908 promoter were functional. Our findings demonstrated that miR-1908 has its own transcription unit, and revealed the transcriptional mechanisms of miR-1908 expression based on NF-kappaB signaling. This study offers a theoretical basis for understanding the transcriptional mechanism of miR-1908 expression and may provide a new strategy for obesity clinical therapy. Show less

As a cholesterol-induced metabolic disease, cholesterolosis of the gallbladder is often resected clinically, which could lead to many complications. The histopathology of cholesterolosis is due to excessive lipid droplet accumulation in epithelial and subcutaneous tissues. The main components of lipid droplets are cholesterol esters (CEs). Removal of CEs from gallbladder epithelial cells (GBECs) is very important for maintaining intracellular cholesterol homeostasis and for treating cholesterol-related diseases. In this study, pioglitazone was used to reduce intracellular CEs. To further elucidate the mechanism, cholesterolosis GBECs were treated with pioglitazone, 22-(R)-hydroxycholesterol (a liver X receptor α (LXRα) agonist), or peroxisome proliferator-activated receptor gamma (PPARγ) siRNA. Western blotting for PPARγ, LXRα, ATP-binding cassette transporter A1 (ABCA1), and neutral cholesteryl ester hydrolase 1 (NCEH1) was performed. At length, cholesterol efflux to apoA-I was measured, and oil red O staining was used to visualize lipid droplet variations in cells. In conclusion, we observed that pioglitazone increased ABCA1 expression in an LXR-dependent manner and NCEH1 expression in an LXRα-independent manner, which mobilized CE hydrolysis and cholesterol efflux to reduce lipid droplet content in cholesterolosis GBECs. Our data provide a plausible alternative to human gallbladder cholesterolosis. Show less

The highly conserved cellular degradation pathway, macroautophagy, regulates the homeostasis of organelles and promotes the survival of T lymphocytes. Previous results indicate that Atg3-, Atg5-, or Pik3c3/Vps34-deficient T cells cannot proliferate efficiently. Here we demonstrate that the proliferation of Atg7-deficient T cells is defective. By using an adoptive transfer and Listeria monocytogenes (LM) mouse infection model, we found that the primary immune response against LM is intrinsically impaired in autophagy-deficient CD8(+) T cells because the cell population cannot expand after infection. Autophagy-deficient T cells fail to enter into S-phase after TCR stimulation. The major negative regulator of the cell cycle in T lymphocytes, CDKN1B, is accumulated in autophagy-deficient naïve T cells and CDKN1B cannot be degraded after TCR stimulation. Furthermore, our results indicate that genetic deletion of one allele of CDKN1B in autophagy-deficient T cells restores proliferative capability and the cells can enter into S-phase after TCR stimulation. Finally, we found that natural CDKN1B forms polymers and is physiologically associated with the autophagy receptor protein SQSTM1/p62 (sequestosome 1). Collectively, autophagy is required for maintaining the expression level of CDKN1B in naïve T cells and selectively degrades CDKN1B after TCR stimulation. Show less

MicroRNA-452 (miRNA-452) was overexpressed in docetaxel-resistant human breast cancer MCF-7 cells (MCF-7/DOC). However, its role in modulating the sensitivity of breast cancer cells to docetaxel (DOC) remains unclear. The aim of this study is to investigate the role of miRNA-452 in the sensitivity of breast cancer cells to DOC.Real-time quantitative PCR (RT-qPCR) were used to identify the differential expression of miRNA-452 between MCF-7/DOC and MCF-7 cells. MiRNA-452 mimic was transfected into MCF-7 cells and miRNA-452 inhibitor was transfected into MCF-7/DOC cells. The role of miRNA-452 in these transfected cells was evaluated using RT-qPCR, MTT assay, and flow cytometry assay. The relationship of miRNA-452 and its predictive target gene "anaphase-promoting complex 4" (APC4) was analyzed by RT-qPCR and Western blot.MiRNA-452 showed significantly higher expression (78.9-folds) in MCF-7/DOC cells compared to parental MCF-7 cells. The expression of miRNA-452 in the mimic transfected MCF-7 cells was upregulated 212.2-folds (P < 0.05) compared to its negative control (NC), and the half maximal inhibitory concentration (IC50) value of DOC (1.98 ± 0.15 μM) was significantly higher than that in its NC (0.85 ± 0.08 μM, P < 0.05) or blank control (1.01 ± 0.19 μM, P < 0.05). Furthermore, its apoptotic rate (6.3 ± 1.3 %) was distinctly decreased compared with that in its NC (23.8 ± 6.6 %, P < 0.05) or blank control (18.6 ± 4.7 %, P < 0.05). In contrast, the expression of miRNA-452 in the inhibitor-transfected MCF-7/DOC cells was downregulated 0.58-fold (P < 0.05) compared to its NC, the IC50 value of DOC (44.5 ± 3.2 μM) was significantly lower than that in its NC (107.3 ± 6.63 μM, P < 0.05) or blank control (102.22 ± 11.34 μM, P < 0.05), and the apoptotic rate (45.5 ± 10.8 %) was distinctly increased compared with its NC (9.9 ± 2.2 %, P < 0.05) and blank control (9.4 ± 2.5 %, P < 0.05). Further, there was an inverse association between miRNA-452 and APC4 expression in breast cancer cells in vitro.Dysregulation of miRNA-452 involved in the DOC resistance formation of breast cancer cells may be, in part, via targeting APC4. Show less