👤 Dan Luo

Decidualization is required for the successful establishment of pregnancy in rodents and primates. Fatty acid desaturase 3 (Fads3) belongs to the fatty acid desaturase family, which is a crucial enzyme for highly unsaturated fatty acid biosynthesis. However, the expression, regulation and function of Fads3 during early pregnancy in mice are still unknown. In this study, we examined Fads3 expression, regulation and function during mouse decidualization. The expression of Fads3 is detected in the subluminal stromal cells at implantation site on day 5 of pregnancy, but not at inter-implantation site and in day 5 pseudopregnant uteri. Compared to delayed implantation, Fads3 is strongly expressed after delayed implantation is activated by estrogen treatment. From days 6 to 8, Fads3 mRNA signals are significantly detected in the decidua. In ovariectomized mice, estrogen significantly stimulates Fads3 expression. However, estrogen has no effect on Fads3 expression in ovariectomized ERα-deficient mice, suggesting that estrogen regulation on Fads3 expression is ERα dependent. When ovariectomized mice were treated with progesterone, Fads3 expression is significantly increased by progesterone. Progesterone stimulation on Fads3 expression is also detected in cultured stromal cells, which is abrogated by RU486 treatment. These data indicate that progesterone upregulation on Fads3 expression is progesterone receptor-dependent. Fads3 knockdown by siRNA reduces in vitro decidualization of mouse stromal cells. Taken together, Fads3 may play an important role during mouse decidualization. Show less

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is the most abundant and carcinogenic tobacco-specific nitrosamine in tobacco and tobacco smoke. The major metabolic pathway for NNK is carbonyl reduction to form the (R) and (S) enantiomers of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) which, like NNK, is a potent lung carcinogen. The goal of this study was to characterize NNAL enantiomer formation in human lung and identify the enzymes responsible for this activity. While (S)-NNAL was the major enantiomer of NNAL formed in incubations with NNK in lung cytosolic fractions, (R)-NNAL comprised ~60 and ~95% of the total NNAL formed in lung whole cell lysates and microsomes, respectively. In studies examining the role of individual recombinant cytosolic reductase enzymes in lung NNAL enantiomer formation, AKR1C1, AKR1C2, AKR1C3, AKR1C4 and CBR1 all exhibited (S)-NNAL-formation activity. To identify the microsomal enzymes responsible for (R)-NNAL formation, 28 microsomal reductase enzymes were screened for expression by real-time PCR in normal human lung. HSD17β6, HSD17β12, KDSR, NSDHL, RDH10, RDH11 and SDR16C5 were all expressed at levels ≥HSD11β1, the only previously reported microsomal reductase enzyme with NNK-reducing activity, with HSD17β12 the most highly expressed. Of these lung-expressing enzymes, only HSD17β12 exhibited activity against NNK, forming primarily (>95%) (R)-NNAL, a pattern consistent with that observed in lung microsomes. siRNA knock-down of HSD17β12 resulted in significant decreases in (R)-NNAL-formation activity in HEK293 cells. These data suggest that both cytosolic and microsomal enzymes are active against NNK and that HSD17β12 is the major active microsomal reductase that contributes to (R)-NNAL formation in human lung. Show less

Testosterone supplementation has been linked to increased cardiovascular disease risk in some observational studies. The causal role of testosterone can be investigated using a Mendelian randomization approach. We assessed genetic associations of variants in two gene regions (SHBG and JMJD1C) with several cardiovascular risk factors (lipids, adiponectin, blood pressure, anthropometric traits) plus male pattern baldness, including control outcomes and potential mediators. We assessed genetic associations with coronary artery disease (CAD) risk in the CARDIoGRAMplusC4D consortium (171,191 individuals including 60,801 cases), and associations with CAD and ischaemic stroke risk in the UK Biobank (367,643 individuals including 25,352 CAD cases and 3650 ischaemic stroke cases). Genetic predictors of increased serum testosterone were associated with lipids, blood pressure, and height. There was some evidence of an association with risk of CAD (SHBG gene region: odds ratio (OR) 0.95 per 1 unit increase in log-transformed testosterone [95% confidence interval: 0.81-1.12, p = 0.55]; JMJD1C gene region: OR 1.24 [1.01-1.51, p = 0.04]) and ischaemic stroke both overall (SHBG: OR 1.05 [0.64, 1.73, p = 0.83]; JMJD1C: OR 2.52 [1.33, 4.77, p = 0.005]) and in men. However, associations with some control outcomes were in the opposite direction to that expected. Sex hormone-related mechanisms appear to be relevant to cardiovascular risk factors and for stroke (particularly for men). However, the extent that these findings are specifically informative about endogenous testosterone or testosterone supplementation is unclear. These findings underline a fundamental limitation for the use of Mendelian randomization where biological knowledge about the function of genetic variants is uncertain. Show less

Non-small-cell lung cancer (NSCLC) has been recognized as a highly heterogeneous disease with phenotypic and genotypic diversity in each subgroup. While never-smoker patients with NSCLC have been well studied through next generation sequencing, we have yet to recognize the potentially unique molecular features of young never-smoker patients with NSCLC. In this study, we conducted whole genome sequencing (WGS) to characterize the genomic alterations of 36 never-smoker Chinese patients, who were diagnosed with lung adenocarcinoma (LUAD) at 45 years or younger. Besides the well-known gene mutations (e.g., TP53 and EGFR), our study identified several potential lung cancer-associated gene mutations that were rarely reported (e.g., HOXA4 and MST1). The lung cancer-related copy number variations (e.g., EGFR and CDKN2A) were enriched in our cohort (41.7%, 15/36) and the lung cancer-related structural variations (e.g., EML4-ALK and KIF5B-RET) were commonly observed (22.2%, 8/36). Notably, new fusion partners of ALK (SMG6-ALK) and RET (JMJD1C-RET) were found. Furthermore, we observed a high prevalence (63.9%, 23/36) of potentially targetable genomic alterations in our cohort. Finally, we identified germline mutations in BPIFB1 (rs6141383, p.V284M), CHD4 (rs74790047, p.D140E), PARP1 (rs3219145, p.K940R), NUDT1 (rs4866, p.V83M), RAD52 (rs4987207, p.S346*), and MFI2 (rs17129219, p.A559T) were significantly enriched in the young never-smoker patients with LUAD when compared with the in-house noncancer database (p < 0.05). Our study provides a detailed mutational portrait of LUAD occurring in young never-smokers and gives insights into the molecular pathogenesis of this distinct subgroup of NSCLC. Show less

Type 2 diabetes (T2D) is generally regarded as a metabolic disorder disease with various phenotypic expressions. Traditional Chinese medicine (TCM) has been widely used for preventing and treating diabetes. In our study, we demonstrated that Cyclocarya paliurus formula extractum (CPE), a compound of TCM, can ameliorate diabetes in diabetic rats. Transcriptome profiles were performed to elucidate the anti-diabetic mechanisms of CPE on pancreas and liver. Pancreatic transcriptome analysis showed CPE treatment significantly inhibited gene expressions related to inflammation and apoptosis pathways, among which the transcription factors (TFs) nuclear factor κB (NF-κB), STAT, and miR-9a/148/200 may serve as core regulators contributing to ameliorate diabetes. Biochemical studies also demonstrated CPE treatment decreased pro-inflammatory cytokines (tumor necrosis factor alpha [TNF-α], interleukin [IL]-1β, and IL-6) and reduced β cell apoptosis. In liver tissue, our transcriptome and biochemical experiments showed that CPE treatment reduced lipid accumulation and liver injury, and it promoted glycogen synthesis, which may be regulated by TFs Srebf1, Mlxipl, and miR-122/128/192. Taken together, our findings revealed CPE could be used as a potential therapeutic agent to prevent and treat diabetes. It is the first time to combine transcriptome and regulatory network analyses to study the mechanism of CPE in preventing diabetes, giving a demonstration of exploring the mechanism of TCM on complex diseases. Show less

Chromium (Cr) is one of the most important environmental pollutants which are released into the environment due to their wide usage in numerous industries. The excess of Cr (VI) can induce hepatotoxicity, while the molecular mechanism that is involved in Cr (VI)-induced hepatotoxicity is unclear. We demonstrated the induction of chromium poisoning model in chickens to identify the differentially expressed genes (DEGs), and their functions were analyzed under different physiological and pathological conditions. Histopathological examination and transcriptome data for chromium-poisoned livers and control livers were annotated with Illumina® HiSeq 2000. The histopathological examination in chromium poisoning groups showed diapedesis, hemolysis, degeneration, nucleus pycnosis, and central phlebectasia in the liver. A total of 334 genes were upregulated and 509 genes were downregulated. The most strongly upregulated genes were HKDC1, DDX4, ACACA, FDFT1, CYYR1, PPP1R3C, and SLC16A14, while the most downregulated genes were MYBPC3, CCKAR, PCK1, and CPT1A. A Gene Ontology (GO) term with the highest enrichment of DEGs is small molecule metabolic process. In cell component domain, the term with the highest enrichment is extracellular matrix. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways showed that glucose metabolism, lipid metabolism, and protein metabolism were the most important metabolic pathways in the liver. The current study first time provides important clues and evidence for identifying the differentially expressed genes in livers due to Cr (VI)-induced liver injury in chickens. Show less

Sirtuin 1 (SIRT1) is a nicotinamide adenine dinucleotide-dependent protein deacetylase. Recent studies have demonstrated that enhancing SIRT1 expression or activity may modulate cholesterol and lipid metabolism. However, pharmacological and molecular regulators for SIRT1 are scarce. Here, we aimed to find novel small molecule modulators of SIRT1 to regulate cholesterol and lipid metabolism. A high-throughput screening assay was established to identify SIRT1 activators. Surface plasmon resonance and immunoprecipitation were performed to confirm the interaction of E1231 with SIRT1. Cholesterol assay was performed to demonstrate the in vitro effect of E1231. The in vivo effect of E1231 was evaluated in experimental models. E1231, a piperazine 1,4-diamide compound, was identified as a SIRT1 activator with EC We identified a novel SIRT1 activator E1231 and elucidated its beneficial effects on lipid and cholesterol metabolism. Our study suggests that E1231 might be developed as a novel drug for treating atherosclerosis. Show less

Increasing evidence suggests that abnormal synaptic function leads to neuronal developmental disorders and is an important component of the etiology of autism spectrum disorder (ASD). Neurexins are presynaptic cell-adhesion molecules that affect the function of synapses and mediate the conduction of nerve signals. Thus, neurexins are attractive candidate genes for autism. Since gene families have greater power to reveal genetic association than single genes, we designed this case-control study to investigate six genetic variants in three neurexin genes (NRXN1, NRXN2, and NRXN3) in a Chinese population including 529 ASD patients and 1,923 healthy controls. We found that two SNPs were significantly associated with ASD after false discovery rate (FDR) adjustment for multiple comparisons. The NRXN2 rs12273892 polymorphism T allele and AT genotype were significantly associated with increased risk of ASD (respectively: OR = 1.328, 95% CI = 1.133-1.557, P < 0.001; OR = 1.528; 95% CI = 1.249-1.868, P < 0.001). The dominant model showed the same association (OR = 1.495, 95% CI = 1.231-1.816, P < 0.001). The NRXN3 rs12879016 polymorphism played a significant role in ASD susceptibility under the dominant model (OR = 0.747, 95% CI= 0.615-0.908, P = 0.023), with the same trend detected for the G allele and GT genotype (respectively: OR = 0.811, 95% CI = 0.699-0.941, P = 0.036; OR = 0.755, 95% CI = 0.615-0.928, P = 0.035). In conclusion, this study supports the importance of two genetic variants in the neurexin gene family in ASD susceptibility in China. Autism Res 2018, 11: 37-43. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. Autism spectrum disorder (ASD) is a neurodevelopmental disorder that is highly heritable, and studies have found a number of candidate genes that might contribute to ASD. Neurexins are presynaptic cell-adhesion molecules that affect the function of synapses and mediate the conduction of nerve signals, and they play an important role in normal brain development and become candidate genes for autism. The purpose of our study is to explore the association between variants of the neurexins gene family and ASD in a Chinese population through a case-control study. Show less

Colorectal carcinoma is one of the leading causes of cancer-related deaths and has a high tendency for metastasis, which makes it a priority to find novel methods to diagnose and treat colorectal carcinoma at a very early stage. We studied the role of the regulator of G-protein signaling (RGS) family of proteins RGS17 in colorectal carcinoma growth and metastasis. We found that RGS17 was upregulated in both clinical colorectal carcinoma tissues and cultured colorectal carcinoma cells. Knockdown of RGS17 by specific siRNA decreased the cell proliferation rate, whereas overexpression of RGS17 with expression plasmid increased the rate in cultured cells. Consistently, a mouse model for colorectal carcinoma also showed that depletion of RGS17 significantly inhibited tumor growth in vivo. Moreover, a Transwell assay showed that RGS17 promoted the ability of colorectal carcinoma cells to migrate and invade. These data suggest that RGS17 is overexpressed in colorectal carcinoma and promotes cell proliferation, migration, and invasion. Show less

Diabetic retinopathy (DR) is a major cause of adult blindness. Retinal Müller cells maintain water homeostasis and potassium concentration via inwardly rectifying Kir4.1 channels. Accumulation of advanced glycation end products (AGEs) is a major pathologic event in DR. While diabetes leads to a decrease in the Kir4.1 channels, it remains unknown whether AGEs-linked to the basement membrane (BM) affect normal Kir4.1 channels. For this study, we hypothesized that AGE-modification of laminin is detrimental to Kir4.1 channels, therefore, disrupting Müller cell function. The AGE-modified laminin-coated substrates were prepared by incubating Petri-dishes with laminin and methylglyoxal for seven days. The rat Müller cells (rMC-1) were propagated on AGE-modified laminin, and Kir4.1 expression and function were evaluated. Quantification of AGEs using ELISA revealed a dose-dependent increase in methylglyoxal-hydro-imidazolone adducts. The rMC-1 propagated on AGE-modified laminin demonstrated a decrease in Kir4.1 levels in immunofluorescence and western blot studies and a decrease in the Kir4.1 channel function. Kir4.1 decrease on AGE-modified laminin resulted in a disorganization of an actin cytoskeleton and disruption of α-dystroglycan-syntrophin-dystrophin complexes. Our studies suggest that AGE-modification of laminin is detrimental to Kir4.1 channels. By studying the role of AGEs in Kir4.1 channels we have identified a novel mechanism of Müller cell dysfunction and its subsequent involvement in DR. Show less

The present study aimed to determine the mechanisms of action of curcumin in osteosarcoma. Human osteosarcoma U-2 OS cells was purchased from the Cell Bank of the Chinese Academy of Sciences. RNA sequencing analysis was performed for 2 curcumin-treated samples and 2 control samples using Illumina deep sequencing technology. The differentially expressed genes were identified using Cufflink software. Enrichment and protein-protein interaction network analyses were performed separately using cluster Profiler package and Cytoscape software to identify key genes. Then, the mRNA levels of key genes were detected by quantitative reverse transcription polymerase chain reaction (RT-qPCR) in U-2 OS cells. Finally, cell apoptosis, proliferation, migration and invasion arrays were performed. In total, 201 DEGs were identified in the curcumin-treated group. EEF1A1 (degree=88), ATF7IP, HIF1A, SMAD7, CLTC, MCM10, ITPR1, ADAM15, WWP2 and ATP5C1, which were enriched in 'biological process', exhibited higher degrees than other genes in the PPI network. RT-qPCR demonstrated that treatment with curcumin was able to significantly increase the levels of CLTC and ITPR1 mRNA in curcumin-treated cells compared with control. In addition, targeting ITPR1 with curcumin significantly promoted apoptosis and suppressed proliferation, migration and invasion. Targeting ITPR1 via curcumin may serve an anticancer role by mediating apoptosis, proliferation, migration and invasion in U-2 OS cells. Show less

Non-small cell lung cancer (NSCLC) has led to the highest cancer-related mortality for decades. To enhance the efficiency of early diagnosis and therapy, more efforts are urgently needed to reveal the origins of NSCLC. In this study, we explored the effect of miR-542-5p in NSCLC with clinical samples and in vivo models and further explored the prospective function of miR-542-5p though bioinformatics methods. A total of 125 NSCLC tissue samples were collected, and the expression of miR-542-5p was detected by qRT-PCR. The relationship between miR-542-5p level and clinicopathological features was analyzed. The effect of miR-542-5p on survival time was also explored with K-M survival curves and Cox's regression. The effect of miR-542-5p on the tumorigenesis of NSCLC was verified with a chick chorioallantoic membrane (CAM) model. The potential target genes were predicted by bioinformatics tools, and relevant pathways were analyzed by GO and KEGG. Several hub genes were validated by Proteinatlas. The expression of miR-542-5p was down-regulated in NSCLC tissues, and consistent results were also found in the subgroups of adenocarcinoma and squamous cell carcinoma. Down-regulation of miR-542-5p was found to be connected with advanced TNM stage, vascular invasion, lymphatic metastasis and EGFR. Survival analyses showed that patients with lower miR-542-5p levels had markedly poorer prognosis. Both tumor growth and angiogenesis were significantly suppressed by miR-542-5p mimic in the CAM model. The potential 457 target genes of miR-542-5p were enriched in several key cancer-related pathways, such as morphine addiction and the cAMP signaling pathway from KEGG. Interestingly, six genes (GABBR1, PDE4B, PDE4C, ADCY6, ADCY1 and GIPR) from the cAMP signaling pathway were confirmed to be overexpressed in NSCLCs tissues. This evidence suggests that miR-542-5p is a potential tumor-suppressed miRNA in NSCLC, which has the potential to act as a diagnostic and therapeutic target of NSCLC. Show less

Estrogen had been found to be negatively associated with serum triglyceride (TG) levels. Apolipoprotein A5 (APOA5), a novel member of apolipoprotein family, was reported to have a strong ability to decrease serum concentrations of TG. Clinical data found concentrations of APOA5 were higher in woman than that in men, and the negative relationship between APOA5 and TG levels was more significant in woman. These suggests APOA5 may involve in estrogen actions. Therefore, we hypothesize estrogen up-regulates serum concentrations of APOA5 and subsequently decreases serum TG levels. We will design the following experiments to test this hypothesis. (1) We will treat wild and APOA5-defeted ovariectomized hamster with or without estrogen to examine if estrogen could up-regulate concentrations of APOA5 and decrease TG levels. (2) We will treat HepG2 cells with estrogen and investigate the possible mechanisms. Show less

The purpose of this study was to investigate the correlation between serum levels of serum apolipoprotein M (ApoM), A5 (ApoA5), and high-density lipoprotein (HDL) in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and study the effects of nasal continuous positive airway pressure treatment on these serum biomarkers. Thirty OSAHS patients and 15 non-OSAHS probands as control were selected for the study. Serum HDL, ApoM, and ApoA5 levels in two groups were detected; differences and association among them were analyzed. Patients with moderate and severe OSAHS underwent 3-month auto-continuous positive airway pressure treatment, and a comparative study was conducted to investigate the changes in blood lipids, serum ApoM, and ApoA5. In comparison to the control group, the HDL, ApoM, and ApoA5 serum levels were lower (P < 0.05). HDL was positively correlated to ApoM and ApoA5 (P < 0.001), and ApoM was positively correlated to ApoA5 (r = 0.536, P < 0.001). HDL, ApoM, and ApoA5 were significantly increased in the patients of moderate and severe OSAHS after auto-continuous positive airway pressure treatment for 3 months (P < 0.05). The HDL level was significantly lower in OSAHS patients. The decrease in serum ApoM and ApoA5 in OSAHS patients was correlated to the severity of OSAHS and HDL levels. Auto-continuous positive airway pressure treatment increased serum levels of ApoM, ApoA5, and HDL in OSAHS patients. Show less

Colorectal cancer (CRC) is one of the most common malignancies worldwide with poor prognosis. Studies have showed that abnormal microRNA (miRNA) expression can affect CRC pathogenesis and development through targeting critical genes in cellular system. However, it is unclear about which miRNAs play central roles in CRC's pathogenesis and how they interact with transcription factors (TFs) to regulate the cancer-related genes. To address this issue, we systematically explored the major regulation motifs, namely feed-forward loops (FFLs), that consist of miRNAs, TFs and CRC-related genes through the construction of a miRNA-TF regulatory network in CRC. First, we compiled CRC-related miRNAs, CRC-related genes, and human TFs from multiple data sources. Second, we identified 13,123 3-node FFLs including 25 miRNA-FFLs, 13,005 TF-FFLs and 93 composite-FFLs, and merged the 3-node FFLs to construct a CRC-related regulatory network. The network consists of three types of regulatory subnetworks (SNWs): miRNA-SNW, TF-SNW, and composite-SNW. To enhance the accuracy of the network, the results were filtered by using The Cancer Genome Atlas (TCGA) expression data in CRC, whereby we generated a core regulatory network consisting of 58 significant FFLs. We then applied a hub identification strategy to the significant FFLs and found 5 significant components, including two miRNAs (hsa-miR-25 and hsa-miR-31), two genes (ADAMTSL3 and AXIN1) and one TF (BRCA1). The follow up prognosis analysis indicated all of the 5 significant components having good prediction of overall survival of CRC patients. In summary, we generated a CRC-specific miRNA-TF regulatory network, which is helpful to understand the complex CRC regulatory mechanisms and guide clinical treatment. The discovered 5 regulators might have critical roles in CRC pathogenesis and warrant future investigation. Show less

A series of pentacyclic triterpene 3β-ester derivatives were designed, synthesized and evaluated as a new class of cholesteryl ester transfer protein (CETP) inhibitors for the treatment of dyslipidemia. In vitro screening assay showed that 5 out of 30 compounds displayed moderate inhibiting human CETP activity with IC Show less

Serine-arginine protein kinase 1 (SRPK1) phosphorylates proteins involved in the regulation of several mRNA processing pathways including alternative splicing. SRPK1 has been reported to be over-expressed in multiple cancers including prostate, breast, lung and glioma. Several studies further identified that inhibition of SRPK1 showed tumor-suppressive effects, thus raising SRPK1 as a novel candidate chemotherapy target. Interestingly, SRPK1 plays tumor suppressing role in mouse embryonic fibroblasts, on that SRPK1-silencing induces cell transformation. Therefore, the effect of SRPK1 seems heterogeneously in different cell types and tissues. The existence and role of SRPK1 in gastric cancer (GC) hasn't been reported. Here we investigated the expression pattern of SRPK1 in GC by immunohistochemistry and found that it was up-regulated in tumor tissues, where its expression was correlated with tumor grade and prognosis. Further, we explored the signaling mechanism of SRPK1 in promoting GC progression, which revealed that both PP2A and DUSP6 phosphatases impaired the oncogenic effects of SRPK1. However, we didn't find any direct interaction between SRPK1 with PP2A or DUSP6, indicating PP2A and DUSP6 function by regulating the downstream effectors of SRPK1. Our study not only revealed the clinical significance of SRPK1 in GC, but also provided new evidence for its signaling modulation which is invaluable for novel chemotherapy development. Show less

To develop a cost-effective molecular regulator to improve growth metabolism and immunity of animals, a recombinant plasmid co-expressing fatty acid desaturase (mFat-1) and pig insulin growth like factor 1 (IGF-1) genes was constructed by the 2 A self-cleavage technique. After entrapment within modified chitosan nanoparticles (chitosan modified with polyethyleneglycol-polyethylenimine, CPP), the recombinant plasmid was injected intramuscularly into mice. Compared with controls, co-expression of mFat-1 and IGF-1 significantly raised the level of serum IGF-1, and increased the liver and muscle docosa hexaenoic acid (DHA) content. Th and Tc cell levels were also elevated, as were expression levels of serum IL-4 and IL-6 genes. These results demonstrate that the immunity and metabolism of an animal can be effectively improved by co-expression of mFat-1 and IGF-1 genes in vivo, which may contribute to further development of novel immunomodulators with beneficial effects on growth metabolism and immunity. Show less

Congenital heart defects are the most common birth defects worldwide. Although defective Notch signaling is the major cause of mouse embryonic death from cardiovascular defects, how Notch signaling is regulated during embryonic vasculogenesis and heart development is poorly understood. Regulator of G protein signaling 6 (RGS6) RGS6 and oxidized CaMKIIδ together function as novel critical upstream modulators of Notch signaling required for normal cardiovascular development and embryo survival. Their combined need indicates that they function in parallel pathways needed for Notch1 signaling in yolk sac, placenta and embryos. Thus, dysregulated embryonic RGS6 expression and oxidative activation of CaMKII may potentially contribute to congenital heart defects. Show less

The myogenic regulatory factor MyoD has been implicated as a key regulator of myogenesis, and yet there is little information regarding its upstream regulators. We found that Deltex2 inhibits myogenic differentiation in vitro, and that skeletal muscle stem cells from Deltex2 knockout mice exhibit precocious myogenic differentiation and accelerated regeneration in response to injury. Intriguingly, Deltex2 inhibits myogenesis by suppressing Show less

Diabetic patients often are affected by vision problems. We previously identified diabetic retinopathy (DR) as a disease of clock gene dysregulation. TNF-α, a proinflammatory cytokine, is known to be elevated in DR. Müller cells maintain retinal water homeostasis and K+ concentration via Kir4.1 channels. Notably, Kir4.1 expression is reduced in diabetes; however, the interplay of TNF-α, Kir4.1, and clock genes in Müller cells remains unknown. We hypothesize that the Kir4.1 in Müller cells is under clock regulation, and increase in TNF-α is detrimental to Kir4.1. Long-Evans rats were made diabetic using streptozotocin (STZ). Retinal Kir4.1 expression was determined at different time intervals. Rat Müller (rMC-1) cells were transfected with siRNA for Per2 or Bmal1 and in parallel treated with TNF-α (5-5000 pM) to determine Kir4.1 expression. Kir4.1 expression exhibited a diurnal rhythm in the retina; however, with STZ-induced diabetes, Kir4.1 was reduced overall. Kir4.1 rhythm was maintained in vitro in clock synchronized rMC-1 cells. Clock gene siRNA-treated rMC-1 exhibited a decrease in Kir4.1 expression. TNF-α treatment of rMCs lead to a profound decrease in Kir4.1 due to reduced colocalization of Kir4.1 channels with synapse-associated protein (SAP97) and disorganization of the actin cytoskeleton. Our findings demonstrate that Kir4.1 channels possess a diurnal rhythm, and this rhythm is dampened with diabetes, thereby suggesting that the increase in TNF-α is detrimental to normal Kir4.1 rhythm and expression. Show less

Hepatocellular carcinoma (HCC) ranks as the third leading cause of cancer-related mortality in China with increasing incidence. This study is designed to explore early genetic changes implicated in HCC tumorigenesis and progression by whole-exome sequencing. We firstly sequenced the whole exomes of 5 paired hepatitis B virus-related early-stage HCC and peripheral blood samples, followed by gene ontological analysis and pathway analysis of the single-nucleotide variants discovered. Then, the mutations of high frequency were further confirmed by Sanger sequencing. We identified a mutational signature of dominant T:A>A:T transversion in early HCC and significantly enriched pathways including ECM-receptor interaction, axon guidance, and focal adhesion and enriched biological processes containing cell adhesion, axon guidance, and regulation of pH. Eight genes, including MUC16, UNC79, USH2A, DNAH17, PTPN13, TENM4, PCLO, and PDE1C, were frequently mutated. This study reveals a mutational profile and a distinct mutation signature of T:A>A:T transversion in early-stage HCC with HBV infection, which will enrich our understanding of genetic characteristics of the early-stage HCC. Show less

Although major depressive disorder (MDD) has low heritability, a genome-wide association study in humans has recently implicated type 3 adenylyl cyclase (AC3; ADCY3) in MDD. Moreover, the expression level of AC3 in blood has been considered as a MDD biomarker in humans. Nevertheless, there is a lack of supporting evidence from animal studies. We employed multiple approaches to experimentally evaluate if AC3 is a contributing factor for major depression using mouse models lacking the Adcy3 gene. We found that conventional AC3 knockout (KO) mice exhibited phenotypes associated with MDD in behavioral assays. Electroencephalography/electromyography recordings indicated that AC3 KO mice have altered sleep patterns characterized by increased percentage of rapid eye movement sleep. AC3 KO mice also exhibit neuronal atrophy. Furthermore, synaptic activity at cornu ammonis 3-cornu ammonis 1 synapses was significantly lower in AC3 KO mice, and they also exhibited attenuated long-term potentiation as well as deficits in spatial navigation. To confirm that these defects are not secondary responses to anosmia or developmental defects, we generated a conditional AC3 floxed mouse strain. This enabled us to inactivate AC3 function selectively in the forebrain and to inducibly ablate it in adult mice. Both AC3 forebrain-specific and AC3 inducible knockout mice exhibited prodepression phenotypes without anosmia. This study demonstrates that loss of AC3 in mice leads to decreased neuronal activity, altered sleep pattern, and depression-like behaviors, providing strong evidence supporting AC3 as a contributing factor for MDD. Show less

To explore whether plasma fatty acids and SNPs in the fatty acid desaturase (FADS) gene associated with type 2 diabetes (T2D) and coronary artery disease (CAD). In this cross-sectional study, we utilized gas chromatography-mass spectrometric analysis and the high-resolution melting method to detect plasma fatty acids and SNPs respectively (rs174537G>T, rs174616C>T, rs174460T>C, and rs174450A>C) in 234 T2D, 200 CAD, 185 T2D&CAD patients, and 253 healthy controls. We found that T2D&CAD patients had the highest plasma arachidonic acid, dihomo-gamma-linolenic acid and delta-6 desaturase, and the lowest stearic acid, linolenic acid, and saturated fatty acids; plasma eicosapentaenoic acid and docosahexaenoic acid elevated in T2D patients, but significantly reduced in CAD patients. Moreover, T2D patients with rs174537 GG genotype were at risk of developing T2D&CAD (odds ratio (OR) 1.763; 95 % CI 1.143-2.718; p = 0.010), with elevated plasma LDL-cholesterol, arachidonic acid, and delta-6 desaturase. Our results show that SNPs in FADS gene (particularly rs174537) associate with plasma fatty acids and desaturase levels in patients with both T2D and CAD, which maybe increases the risk of CAD in diabetic patients. Show less

Sterol regulatory element binding protein 1 (SREBP1; gene name SREBF1) is known to be the master regulator of lipid homeostasis in mammals, including milk fat synthesis. The major role of SREBP1 in controlling milk fat synthesis has been demonstrated in bovine mammary epithelial cells. Except for a demonstrated role in controlling the expression of FASN, a regulatory role of SREBP1 on milk fat synthesis is very likely, but has not yet been demonstrated in goat mammary epithelial cells (GMEC). To explore the regulatory function of SREBP1 on de novo fatty acids and triacylglycerol synthesis in GMEC, we overexpressed the mature form of SREBP1 (active NH2-terminal fragment) in GMEC using a recombinant adenovirus vector (Ad-nSREBP1), with Ad-GFP (recombinant adenovirus of green fluorescent protein) as control, and infected the GMEC for 48 h. In infected cells, we assessed the expression of 20 genes related to milk fat synthesis using real time-quantitative PCR, the protein abundance of SREBP1 and FASN by Western blot, the production of triacylglycerol, and the fatty acid profile. Expression of SREBF1 was modest in mammary compared with the other tissues in dairy goats but its expression increased approximately 30-fold from pregnancy to lactation. The overexpression of the mature form of SREBP1 was confirmed by >200-fold higher expression of SREBF1 in Ad-nSREBP1 compared with Ad-GFP. We observed no changes in amount of the precursor form of SREBP1 protein but a >10-fold increase of the mature form of SREBP1 protein with Ad-nSREBP1. Compared with Ad-GFP cells (control), Ad-nSREBP1 cells had a significant increase in expression of genes related to long-chain fatty acid activation (ACSL1), transport (FABP3), desaturation (SCD1), de novo synthesis of fatty acids (ACSS2, ACLY, IDH1, ACACA, FASN, and ELOVL6), and transcriptional factors (NR1H3 and PPARG). We observed a >10-fold increase in expression of INSIG1 but SCAP was downregulated by Ad-nSREBP1. Among genes related to milk fat synthesis and lipid droplet formation, only LPIN1 and DGAT1 were upregulated by Ad-nSREBP1. Compared with the Ad-GFP, the cellular triacylglycerol content was higher and the percentage of C16:0 and C18:1 increased, whereas that of C16:1, C18:0, and C18:2 decreased in Ad-nSREBP1 cells. Overall, the data provide strong support for a central role of SREBP1 in the regulation of milk fat synthesis in goat mammary cells. Show less

Liver X Receptor (LXR) plays a pivotal role in metabolic regulation in mammals, but little is known about its function in fish. In this study, two lxra isoforms, namely lxra1 and lxra2, were isolated. Their molecular characterization, tissues distribution and transcriptional regulation by insulin in vivo and in vitro were determined. lxrα1 and lxrα2 cDNA covered 2775bp and 3093bp, encoding 446 and 515 amino acid residues, respectively. The protein sequence of yellow catfish lxra included characteristic feature of mammalian lxrs, including the DNA binding (DBD) (containing P-box), ligand binding (LBD) and activation function-2 (AF-2) domains, D-box, and D (hinge) region. Phylogenetic analysis revealed that yellow catfish lxra grouped with lxra of zebrafish but was distant from those of medaka and stickleback. lxrβ clades was absent in teleosts in phylogenetic tree, proving gene loss of lxrβ in teleosts during evolution. The two lxra isoforms (lxra1 and lxra2) mRNAs were ubiquitously expressed in 11 tested tissues. Compared to lxra2, lxra1 mRNA expression was predominant in all tested tissues. The expression of lxrα1 was the highest in testis, then in liver, and the lowest in other tissues. lxrα2 expression was the highest in liver, then in testis, and the lowest in ovary. Insulin significantly stimulated the mRNA expression of lxra1 in vitro and in vivo, while the expression of lxra2 remained unchanged after insulin treatment. The present study serves to increase our understanding into the function of lxra in fish. Show less

Macroautophagy/autophagy is a conserved catabolic process that recycles cytoplasmic material during low energy conditions. BECN1/Beclin1 (Beclin 1, autophagy related) is an essential protein for function of the class 3 phosphatidylinositol 3-kinase (PtdIns3K) complexes that play a key role in autophagy nucleation and elongation. Here, we show that AMP-activated protein kinase (AMPK) regulates autophagy by phosphorylating BECN1 at Thr388. Phosphorylation of BECN1 is required for autophagy upon glucose withdrawal. BECN1(T388A), a phosphorylation defective mutant, suppresses autophagy through decreasing the interaction between PIK3C3 (phosphatidylinositol 3-kinase catalytic subunit type 3) and ATG14 (autophagy-related 14). The BECN1(T388A) mutant has a higher affinity for BCL2 than its wild-type counterpart; the mutant is more prone to dimer formation. Conversely, a BECN1 phosphorylation mimic mutant, T388D, has stronger binding to PIK3C3 and ATG14, and promotes higher autophagy activity than the wild-type control. These findings uncover a novel mechanism of autophagy regulation. Show less

Human mutations in PQBP1, a molecule involved in transcription and splicing, result in a reduced but architecturally normal brain. Examination of a conditional Pqbp1-knockout (cKO) mouse with microcephaly failed to reveal either abnormal centrosomes or mitotic spindles, increased neurogenesis from the neural stem progenitor cell (NSPC) pool or increased cell death in vivo. Instead, we observed an increase in the length of the cell cycle, particularly for the M phase in NSPCs. Corresponding to the developmental expression of Pqbp1, the stem cell pool in vivo was decreased at E10 and remained at a low level during neurogenesis (E15) in Pqbp1-cKO mice. The expression profiles of NSPCs derived from the cKO mouse revealed significant changes in gene groups that control the M phase, including anaphase-promoting complex genes, via aberrant transcription and RNA splicing. Exogenous Apc4, a hub protein in the network of affected genes, recovered the cell cycle, proliferation, and cell phenotypes of NSPCs caused by Pqbp1-cKO. These data reveal a mechanism of brain size control based on the simple reduction of the NSPC pool by cell cycle time elongation. Finally, we demonstrated that in utero gene therapy for Pqbp1-cKO mice by intraperitoneal injection of the PQBP1-AAV vector at E10 successfully rescued microcephaly with preserved cortical structures and improved behavioral abnormalities in Pqbp1-cKO mice, opening a new strategy for treating this intractable developmental disorder. Show less