RESUMEN

Bovine intramuscular fat (IMF), commonly referred to as marbling, is regulated by lipid metabolism, which includes adipogenesis, lipogenesis, glycerolipid synthesis, and lipolysis. In recent years, breeding researchers have identified single nucleotide polymorphisms (SNPs) as useful marker-assisted selection tools for improving marbling scores in national breeding programs. These included causal SNPs that induce phenotypic variation. MicroRNAs (miRNAs) are small highly conserved non-coding RNA molecules that bind to multiple non-coding regions. They are involved in post-transcriptional regulation. Multiple miRNAs may regulate a given target. Previously, three SNPs in the GPAM 3' UTR and four miRNAs were identified through in silico assays. The aim of this study is to verify the binding ability of the four miRNAs to the SNPs within the 3'UTR of GPAM, and to identify the regulatory function of miR-375 in the expression of genes related to lipid metabolism in mammalian adipocytes. It was verified that the four miRNAs bind to the GPAM 3'UTR, and identified that the miR-375 sequence is highly conserved. Furthermore, it was founded that miR-375 upregulated the GPAM gene, C/EBPα, PPARγ and lipid metabolism-related genes and promoted lipid droplet accumulation in 3T3-L1 cells. In conclusion, these results suggest that miR-375 is a multifunctional regulator of multiple lipid metabolism-related genes and may aid in obesity research as a biomarker.

Asunto(s)

Regiones no Traducidas 3' , Células 3T3-L1 , Metabolismo de los Lípidos , MicroARNs , Polimorfismo de Nucleótido Simple , MicroARNs/genética , MicroARNs/metabolismo , Animales , Ratones , Metabolismo de los Lípidos/genética , Bovinos , Regulación de la Expresión Génica , Adipocitos/metabolismo , Adipogénesis/genética

RESUMEN

Metabolic alterations, especially in the mitochondria, play important roles in several kinds of cancers, including acute myeloid leukemia (AML). However, AML-specific molecular mechanisms that regulate mitochondrial dynamics remain elusive. Through the metabolite screening comparing CD34+ AML cells and healthy hematopoietic stem/progenitor cells, we identified enhanced lysophosphatidic acid (LPA) synthesis activity in AML. LPA is synthesized from glycerol-3-phosphate by glycerol-3-phosphate acyltransferases (GPATs), rate-limiting enzymes of the LPA synthesis pathway. Among the four isozymes of GPATs, glycerol-3-phosphate acyltransferases, mitochondrial (GPAM) was highly expressed in AML cells, and the inhibition of LPA synthesis by silencing GPAM or FSG67 (a GPAM-inhibitor) significantly impaired AML propagation through the induction of mitochondrial fission, resulting in the suppression of oxidative phosphorylation and the elevation of reactive oxygen species. Notably, inhibition of this metabolic synthesis pathway by FSG67 administration did not affect normal human hematopoiesis in vivo. Therefore, the GPAM-mediated LPA synthesis pathway from G3P represents a critical metabolic mechanism that specifically regulates mitochondrial dynamics in human AML, and GPAM is a promising potential therapeutic target.

Asunto(s)

Leucemia Mieloide Aguda , Dinámicas Mitocondriales , Humanos , Glicerol , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Aciltransferasas , Fosfatos

RESUMEN

The identification of genetic variants associated with fatty liver disease (FLD) from genome-wide association studies started in 2008 when single nucleotide polymorphisms in PNPLA3, the gene encoding patatin-like phospholipase domain-containing 3, were found to be associated with altered hepatic fat content. Since then, several genetic variants associated with protection from, or an increased risk of, FLD have been identified. The identification of these variants has provided insight into the metabolic pathways that cause FLD and enabled the identification of potential therapeutic targets. In this mini-review, we will examine the therapeutic opportunities derived from genetically validated targets in FLD, including oligonucleotide-based therapies targeting PNPLA3 and HSD17B13 that are currently being evaluated in clinical trials for the treatment of NASH (non-alcoholic steatohepatitis).

Asunto(s)

Enfermedad del Hígado Graso no Alcohólico , Humanos , Enfermedad del Hígado Graso no Alcohólico/tratamiento farmacológico , Enfermedad del Hígado Graso no Alcohólico/genética , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Estudio de Asociación del Genoma Completo , Predisposición Genética a la Enfermedad , Hígado/metabolismo , Polimorfismo de Nucleótido Simple

RESUMEN

Somatic mutations in nonmalignant tissues accumulate with age and injury, but whether these mutations are adaptive on the cellular or organismal levels is unclear. To interrogate genes in human metabolic disease, we performed lineage tracing in mice harboring somatic mosaicism subjected to nonalcoholic steatohepatitis (NASH). Proof-of-concept studies with mosaic loss of Mboat7, a membrane lipid acyltransferase, showed that increased steatosis accelerated clonal disappearance. Next, we induced pooled mosaicism in 63 known NASH genes, allowing us to trace mutant clones side by side. This in vivo tracing platform, which we coined MOSAICS, selected for mutations that ameliorate lipotoxicity, including mutant genes identified in human NASH. To prioritize new genes, additional screening of 472 candidates identified 23 somatic perturbations that promoted clonal expansion. In validation studies, liver-wide deletion of Tbx3, Bcl6, or Smyd2 resulted in protection against hepatic steatosis. Selection for clonal fitness in mouse and human livers identifies pathways that regulate metabolic disease.

Asunto(s)

Enfermedades Metabólicas , Enfermedad del Hígado Graso no Alcohólico , Animales , Humanos , Masculino , Ratones , N-Metiltransferasa de Histona-Lisina/genética , Hígado/metabolismo , Mosaicismo , Enfermedad del Hígado Graso no Alcohólico/genética , Enfermedad del Hígado Graso no Alcohólico/metabolismo

RESUMEN

The circadian clock confers daily rhythmicity to many crucial biological processes and behaviors and its disruption is closely associated with carcinogenesis in several types of cancer. Brain and muscle arnt-like protein 1 (BMAL1) is a core circadian rhythm component in mammals and its dysregulation has been shown to contribute to aberrant metabolism in human diseases. However, the biological functions of BMAL1, especially its involvement in aberrant lipid metabolism in hepatocellular carcinoma (HCC), remain elusive. In the present study, we found that BMAL1 was frequently down-regulated in HCC cells mainly due to the up-regulation of miR-494-3p. Down-regulation of BMAL1 was significantly associated with poor survival in HCC patients. BMAL1 down-regulation promoted HCC cell growth and metastasis both in vitro and in vivo. Mechanistically, through cooperating with EZH2, BMAL1 transcriptionally suppressed the expression of glycerol-3-phosphate acyltransferase mitochondrial (GPAM), a key enzyme involved in the regulation of lipid biosynthesis, leading to reduced levels lysophosphatidic acid (LPA), which have long been known as mediator of oncogenesis. Particularly, treatment with SR8278, an activator of BMAL1, exhibited a therapeutic effect on HCC in vitro and in vivo. In conclusion, BMAL1 plays a critical anti-oncogenic role in HCC, providing strong research evidence for BMAL1 as a prospective target for HCC therapy.

Asunto(s)

Fenómenos Biológicos , Carcinoma Hepatocelular , Neoplasias Hepáticas , MicroARNs , Animales , Humanos , Carcinoma Hepatocelular/genética , Regulación hacia Abajo/genética , Factores de Transcripción ARNTL/genética , Neoplasias Hepáticas/genética , Carcinogénesis , MicroARNs/genética , Mamíferos

RESUMEN

Purpose: Our previous study observed that long non-coding RNA PKD2-2-3 (lnc-PKD2-2-3) is related to advanced tumor features and worse prognosis in cholangiocarcinoma (CCA). Then, this study aimed to further explore the linkage between lnc-PKD2-2-3, miR-328, and GPAM, as well as their effects on regulating CCA viability, mobility, and chemosensitivity. Methods: Lnc-PKD2-2-3, miR-328, and GPAM expression in 30 pairs of CCA tumor and adjacent tissues, as well as in CCA cell lines, were determined. Two CCA cell lines (HuCCT1 and TFK1) were transfected by lnc-PKD2-2-3 overexpression plasmid, lnc-PKD2-2-3 siRNA, miR-328 inhibitor, and GPAM siRNA alone or in combination, followed by cell proliferation, apoptosis, invasion, and 5-FU chemosensitivity detection. Besides, xenograft mice were established for validation. Results: Lnc-PKD2-2-3 and GPAM were higher, whereas miR-328 was lower in CCA tissues versus adjacent tissues and also in CCA cell lines versus control cells; meanwhile, they were correlated with each other (all P <0.05). Lnc-PKD2-2-3 knockdown decreased CCA cell proliferation, invasion, and increased apoptosis (all P <0.05), but lnc-PKD2-2-3 overexpression exhibited the opposite and weaker effect. MiR-328 knockdown induced CCA cell proliferation and invasion and also attenuated the effect of lnc-PKD2-2-3-knockdown in these functions (all P <0.05). Subsequently, GPAM knockdown reduced CCA cell proliferation and invasion and also weakened the effect of miR-328-knockdown in these functions (all P <0.05). Additionally, lnc-PKD2-2-3 positively regulated GPAM while negatively regulating miR-328. MiR-328 negatively modified GPAM in CCA cells. Luciferase gene reporter assays verified that lnc-PKD2-2-3 directly bound miR-328 and miR-328 directly bound GPAM. Finally, the lnc-PKD2-2-3/miR-328/GPAM network also regulated the 5-FU chemosensitivity of CCA cells. In vivo experiments further revealed that lnc-PKD2-2-3 overexpression promoted tumor volume and weight but repressed tumor apoptosis in xenograft mice; meanwhile, it increased GPAM expression but decreased miR-328 expression (all P <0.05). Conversely, lnc-PKD2-2-3 knockdown exhibited the opposite effects (all P <0.05). Conclusion: Lnc-PKD2-2-3/miR-328/GPAM ceRNA network promotes CCA proliferation, invasion, and 5-FU chemoresistance.

RESUMEN

Glycerol-3-phosphate acyltransferase mitochondrial (GPAM) is an enzyme in animal lipid metabolism pathways that catalyzes the initial and most committed step of glycerolipid biosynthesis. The present study mainly focused on exploring the relationship between the GPAM gene and the lipid metabolism of mammary epithelial cells and the effect of GPAM on the related pathways of lipid metabolism. The GPAM gene was knocked out entirely in bovine mammary epithelial cells(BMECs) using CRISPR/Cas9 technology, and the mechanism by which the GPAM gene regulates lipid metabolism in BMECs was confirmed. Furthermore, after the complete loss of GPAM, BMECs' triglycerides (TGs) and cholesterol (CHOL) levels were significantly decreased (p < 0.05). Concurrently, the content of octanoic acid, a medium-chain saturated fatty acid, increased substantially in BMECs. RNA-seq of GPAM-/- BMECs revealed that GPAM could affect the expression of genes related to lipid metabolism, downregulated the expression of Acyl-CoA synthetase long-chain family member 5 (ACSL5), Fatty Acid Binding Protein 3 (FABP3), Hormone-sensitive lipase (HSL), Protease, serine-2 (PRSS2), 1-Acylglycerol-3-Phosphate O Acyltransferase 4 (AGPAT4), and regulated the milk synthesis metabolism pathway.The findings revealed that a number of genes were expressed, a number of genes were differentially expressed genes (DEGs), and a number of GO terms were enriched, with a number of GO terms considerably increased. Further, the differentially expressed genes (DEGs) were significantly enriched in Fat digestion and absorption pathway, Fatty acid metabolic pathway, Biosynthesis of unsaturated fatty acids, Biosynthesis of unsaturated fatty acids and steroids, NF-kappa B signalling pathway, MAPK signalling pathway. In conclusion, the current research results show that GPAM is a crucial regulator of BMEC lipid metabolism. GPAM-/- BMEC may also become useful genetic materials and tools for future research on gene functions related to lipid and fatty acid metabolism. This study will contribute to the discovery of gene regulation and molecular mechanisms in milk fat synthesis.

Asunto(s)

Metabolismo de los Lípidos , Glándulas Mamarias Animales , Animales , Sistemas CRISPR-Cas , Bovinos , Células Epiteliales/metabolismo , Ácidos Grasos/metabolismo , Ácidos Grasos Insaturados/metabolismo , Perfilación de la Expresión Génica , Glicerol-3-Fosfato O-Aciltransferasa/genética , Metabolismo de los Lípidos/genética , Glándulas Mamarias Animales/metabolismo , Leche/metabolismo , Fosfatos/metabolismo

RESUMEN

BACKGROUND: Understanding the genetics of liver disease has the potential to facilitate clinical risk stratification. We recently identified acquired somatic mutations in six genes and one lncRNA in pre-existing fatty liver disease. We hypothesised that germline variation in these genes might be associated with the risk of developing steatosis and contribute to the prediction of disease severity. METHODS: Genome-wide association study (GWAS) summary statistics were extracted from seven studies (>1.7 million participants) for variants near ACVR2A, ALB, CIDEB, FOXO1, GPAM, NEAT1 and TNRC6B for: aminotransferases, liver fat, HbA1c, diagnosis of NAFLD, ARLD and cirrhosis. Findings were replicated using GWAS data from multiple independent cohorts. A phenome-wide association study was performed to examine for related metabolic traits, using both common and rare variants, including gene-burden testing. RESULTS: There was no evidence of association between rare germline variants or SNPs near five genes (ACVR2A, ALB, CIDEB, FOXO1 and TNRC6B) and risk or severity of liver disease. Variants in GPAM (proxies for p.Ile43Val) were associated with liver fat (p = 3.6 × 10-13 ), ALT (p = 2.8 × 10-39 ) and serum lipid concentrations. Variants in NEAT1 demonstrated borderline significant associations with ALT (p = 1.9 × 10-11 ) and HbA1c, but not with liver fat, as well as influencing waist-to-hip ratio, adjusted for BMI. CONCLUSIONS: Despite the acquisition of somatic mutations at these loci during progressive fatty liver disease, we did not find associations between germline variation and markers of liver disease, except in GPAM. In the future, larger sample sizes may identify associations. Currently, germline polygenic risk scores will not capture data from genes affected by somatic mutations.

Asunto(s)

Enfermedad del Hígado Graso no Alcohólico , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Hemoglobina Glucada/metabolismo , Humanos , Hígado/metabolismo , Enfermedad del Hígado Graso no Alcohólico/diagnóstico , Enfermedad del Hígado Graso no Alcohólico/genética , Polimorfismo de Nucleótido Simple , Pronóstico

RESUMEN

Cerebral palsy is the most prevalent physical disability in children; however, its inherent molecular mechanisms remain unclear. In the present study, we performed in-depth clinical and molecular analysis on 120 idiopathic cerebral palsy families, and identified underlying detrimental genetic variants in 45% of these patients. In addition to germline variants, we found disease-related postzygotic mutations in ∼6.7% of cerebral palsy patients. We found that patients with more severe motor impairments or a comorbidity of intellectual disability had a significantly higher chance of harbouring disease-related variants. By a compilation of 114 known cerebral-palsy-related genes, we identified characteristic features in terms of inheritance and function, from which we proposed a dichotomous classification system according to the expression patterns of these genes and associated cognitive impairments. In two patients with both cerebral palsy and intellectual disability, we revealed that the defective TYW1, a tRNA hypermodification enzyme, caused primary microcephaly and problems in motion and cognition by hindering neuronal proliferation and migration. Furthermore, we developed an algorithm and demonstrated in mouse brains that this malfunctioning hypermodification specifically perturbed the translation of a subset of proteins involved in cell cycling. This finding provided a novel and interesting mechanism for congenital microcephaly. In another cerebral palsy patient with normal intelligence, we identified a mitochondrial enzyme GPAM, the hypomorphic form of which led to hypomyelination of the corticospinal tract in both human and mouse models. In addition, we confirmed that the aberrant Gpam in mice perturbed the lipid metabolism in astrocytes, resulting in suppressed astrocytic proliferation and a shortage of lipid contents supplied for oligodendrocytic myelination. Taken together, our findings elucidate novel aspects of the aetiology of cerebral palsy and provide insights for future therapeutic strategies.

Asunto(s)

Parálisis Cerebral , Discapacidad Intelectual , Animales , Parálisis Cerebral/genética , Cognición , Estudios de Cohortes , Comorbilidad , Humanos , Discapacidad Intelectual/complicaciones , Discapacidad Intelectual/genética , Ratones

RESUMEN

Many reports have indicated that long non-coding RNAs (lncRNAs) are closely associated with the occurrence and development of various cancers. Musculin antisense RNA 1 (MSC-AS1) is a an lncRNA known to act as an oncogene in several types of human cancers; however, its specific function in lung adenocarcinoma (LUAD) is still unclear. For this study, we designed and conducted experiments to clarify the function of the lncRNA MSC-AS1 in LUAD and its underlying mechanisms. We found that the expression of MSC-AS1 was significantly higher in LUAD tissues and cells than that in normal ones. Through loss-of function assays, we confirmed that the proliferation of LUAD cells was significantly restrained by down-regulation of MSC-AS1 and the rate of cell apoptosis was accelerated. The results from our mechanistic experiments showed that MSC-AS1 interacts with microRNA-33b-5p (miR-33b-5p). Moreover, glycerol-3-phosphate acyltransferase, mitochondrial (GPAM) was found to be a direct target gene of miR-33b-5p, and it has similar functions to MSC-AS1. Further, inhibition of miR-33b-5p or overexpression GPAM reversed the inhibitory effects of MSC-AS1 silencing on LUAD cell growth. In short, MSC-AS1 facilitates LUAD progression through sponging miR-33b-5p to up-regulate GPAM.

Asunto(s)

Adenocarcinoma del Pulmón/metabolismo , Glicerol-3-Fosfato O-Aciltransferasa/metabolismo , Neoplasias Pulmonares/metabolismo , Mitocondrias/enzimología , ARN Largo no Codificante/metabolismo , Adenocarcinoma del Pulmón/patología , Células Cultivadas , Glicerol-3-Fosfato O-Aciltransferasa/genética , Humanos , Neoplasias Pulmonares/patología , MicroARNs/genética , MicroARNs/metabolismo , ARN Largo no Codificante/genética , Regulación hacia Arriba

RESUMEN

Glycerol-3-phosphate acyltransferase, mitochondrial (GPAM) is a rate-limiting enzyme catalyzing triglyceride synthesis. Recently, we demonstrated that the anti-viral drug ribavirin (RBV) reduces GPAM expression by downregulating CCAAT/enhancer-binding protein α (C/EBPα). However, the precise mechanisms of GPAM suppression have remained unclear. Here, we found that RBV suppressed GPAM expression by downregulating not only C/EBPα, but also sterol regulatory element-binding protein-1c (SREBP-1c). We also found that cis-elements regulated by C/EBPα and SREBP-1c functioned as distal and proximal enhancers, respectively, to express hepatocyte- and adipocytes-specific GPAM variants. These results imply that RBV disrupts formation of the enhancer machineries on the GPAM genome by downregulating both transcription factors. Our findings may contribute to the development of treatments for fatty liver diseases caused by aberrant triglyceride synthesis.

Asunto(s)

Antivirales/farmacología , Regulación hacia Abajo/efectos de los fármacos , Regiones Promotoras Genéticas/efectos de los fármacos , Ribavirina/farmacología , Antimetabolitos/farmacología , Proteína alfa Potenciadora de Unión a CCAAT/genética , Línea Celular , Glicerol-3-Fosfato O-Aciltransferasa , Humanos , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/genética

RESUMEN

Recently, we demonstrated that the anti-viral drug ribavirin (RBV) had the ability to suppress lipogenesis through down-regulation of retinoid X receptor α (RXRα) under the control of the intracellular GTP-level and AMP-activated protein kinase-related kinases, especially microtubule affinity regulating kinase 4 (MARK4). RXRα-overexpression attenuated but did not abolish lipogenesis suppression by RBV, implying that additional factor(s) were involved in this suppressive effect. In the present study, we found that the protein level, but not the mRNA level, of CCAAT/enhancer-binding protein α (C/EBPα) was down-regulated by RBV in hepatic cells. Treatment with proteasome inhibitor attenuated RBV-induced down-regulation of C/EBPα, suggesting that RBV promoted degradation of C/EBPα protein via the ubiquitin-proteasome pathway. Depletion of intracellular GTP through inosine monophosphate dehydrogenase inhibition by RBV led to down-regulation of C/EBPα. In contrast, down-regulation of C/EBPα by RBV was independent of RXRα and MARK4. Knockdown of C/EBPα reduced the intracellular neutral lipid levels and the expression of genes related to the triglyceride (TG) synthesis pathway, especially glycerol-3-phosphate acyltransferase, mitochondrial (GPAM), which encodes the first rate-limiting TG enzyme. Overexpression of C/EBPα yielded the opposite results. We also observed that RBV decreased GPAM expression. Moreover, overexpression of GPAM attenuated RBV-induced reduction in the intracellular neutral lipid levels. These data suggest that down-regulation of C/EBPα by RBV leads to the reduction in GPAM expression, which contributes to the suppression of lipogenesis. Our findings about the mechanism of RBV action in lipogenesis suppression will provide new insights for therapy against the active lipogenesis involved in hepatic steatosis and hepatocellular carcinomas.

Asunto(s)

Proteínas Potenciadoras de Unión a CCAAT/metabolismo , Regulación hacia Abajo/efectos de los fármacos , Hepatocitos/metabolismo , Lipogénesis/efectos de los fármacos , Ribavirina/farmacología , Triglicéridos/biosíntesis , Proteínas Potenciadoras de Unión a CCAAT/genética , Línea Celular Tumoral , Técnicas de Silenciamiento del Gen , Hepatocitos/citología , Humanos , Lipogénesis/genética , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Receptor alfa X Retinoide , Triglicéridos/genética

RESUMEN

Intramuscular fat (IMF) has significant effects on the tenderness, juiciness, and flavor of chicken, which are important determinants of poultry meat quality. Although many studies have focused on microRNAs (miRNAs) involved in adipogenesis, little is known about miRNAs associated with poultry IMF deposition or intramuscular adipocyte differentiation. Bioinformatic analysis identified mitochondrial glycerol­3­phosphate acyltransferase (GPAM) as a putative target of miR-223. To explore the role of miR-223 in the process of chicken IMF deposition, loss and gain of function experiments were performed in primary intramuscular preadipocytes using miR-223 mimics, miR-223 inhibitor, and si-GPAM. Our results showed that miR-223 is significantly down-regulated in the breast muscle tissues of Gushi hens at the later-laying period in comparison with hens at the pre-laying period. Using qRT-PCR, we found that miR-223 expression in chicken tissues and intramuscular adipocytes correlates negatively with GPAM expression. Cell transfection experiments suggest that miR-223 inhibits intramuscular adipocyte differentiation via targeting GPAM. Experiments using a dual luciferase reporter system show that GPAM is a direct target of miR-223. Taken together, our results support the hypothesis that miR-223 regulates intramuscular fat deposition in chickens.

Asunto(s)

Adipocitos/citología , Adipocitos/metabolismo , Diferenciación Celular/genética , Regulación del Desarrollo de la Expresión Génica , Glicerol-3-Fosfato O-Aciltransferasa/genética , MicroARNs/genética , Animales , Interferencia de ARN

RESUMEN

@# Objective: To investigate the expression of long non-coding RNASNHG16 (lncRNASNHG16) in colorectal cancer (CRC) tissues and cells, and to explore the mechanism of its regulation on the expression of mitochondrial glycerol-3-phosphate acyltransferase (GPAM) via sponging miR-128-3p. Methods: Sixty pairs of colorectal cancerous tissues and para-cancerous tissues that resected from CRC patients, who underwent surgery in the Department of Anorectal Surgery, Gansu Provincial People’s Hospital during Jan. 2014 and Jan. 2017, were collected for this study; In addition, CRC cell lines (SW480, SW620, HCT116, Caco-2,DLD-1, HT29) and colonic epithelial cell line CCD841 were also collected for the study. The expression of SNHG16 in collected tissues and cell lines was determined by Real-time quantitative PCR (qPCR), and its correlation to the clinicopathological features of CRC patients was also analyzed. SW480 cells were transfected with miR-128-3p mimic, miR-128-3p inhibitor, and si-SNHG16, respectively, and then the mRNA expressions of miR-128-3p and SNHG16 were detected by qPCR, the protein expression of GPAM was determined by Western blotting, and the cell proliferation, apoptosis and invasion were detected by CCK-8 assay, colony formation assay, cell apoptosis assay and Transwell chamber assay, respectively. The binding between SNHG16 and miR-128-3p was validated with dual luciferase reporter gene assay and RNA Immunoprecipitation assay. For in vivo experiment, mouse model of SW480 cell exnograft was constructed, and the effect of SNHG16 knockdown on the growth of exnograft was observed. Results: SNHG16 was found to highly expressed in human CRC tissues and cell lines (all P<0.01), and SNHG16 expression level was associated with lymph node metastasis, Duke's stage and patients’survival (all P<0.01). Knockdown of SNHG16 significantly inhibited CRC cell proliferation and invasion, and induced apoptosis (all P<0.01); After SNHG16 knockdown, the volume of exnograft was obviously reduced (P<0.05). Dual luciferase reporter gene assay and RNA Immunoprecipitation assay validated the interaction between miR-128-3p and SNHG16, and they were negatively correlated with each other in CRC patients (P<0.01). The SNHG16 regulated the expression of its down-stream gene GPAM via endogenously sponging miR-128-3p. Conclusion: SNHG16 regulates GPAM expression in CRC cells by sponging miR-128-3p, and SNHG16 and miR-128-3p may serve as potential targets for the diagnosis and treatment of CRC.

RESUMEN

PURPOSE: We sought to gain a better understanding of the low-dose ionizing radiation (LDIR)-induced molecular changes in transformed pre-malignant cells in their microenvironment. MATERIALS AND METHODS: The cellular response to LDIR was compared and contrasted using immortalized human Epstein-Barr virus-infected B-cells (EBV-B) in mono-culture, co-culture with human bone marrow derived stromal cells (MSC), or under the LDIR-induced bystander effect. The resulting alterations in protein and gene expression (including microRNA, miRNA) were evaluated by isobaric tags for relative and absolute quantification (iTRAQ) proteomics assay, western blot, cDNA array and quantitative reverse transcription polymerase chain reaction (RT-PCR), respectively. RESULTS: The miRNAs let7a, miR-15b, miR-16, and miR-21, and a lipid metabolic miRNA hub miR-23b, were upregulated after LDIR exposure in the mono-cultured EBV-B cells, but were downregulated in EBV-B cells co-irradiated with MSC. A lipid biosynthesis enzyme glycerol-3-phosphate acyltransferase, the common target of these miRNA, was downregulated at the level of protein and mRNA expression in the LDIR-exposed, mono-cultured EBV-B cells and upregulated MSC co-cultured EBV-B cells. CONCLUSIONS: These results suggest a putative miRNA regulatory mechanism controlling the LDIR-induced stress response, and illustrate that LDIR exposure, and the cell's microenvironment, can affect specific gene expression, both directly and indirectly, resulting in altered protein expression.

Asunto(s)

Linfocitos B/fisiología , Linfocitos B/virología , Regulación Enzimológica de la Expresión Génica/fisiología , Genómica/métodos , Glicerol-3-Fosfato O-Aciltransferasa/metabolismo , Herpesvirus Humano 4/fisiología , Linfocitos B/efectos de la radiación , Línea Celular , Relación Dosis-Respuesta en la Radiación , Regulación Enzimológica de la Expresión Génica/efectos de la radiación , Herpesvirus Humano 4/efectos de la radiación , Humanos , Dosis de Radiación , Integración de Sistemas

RESUMEN

OBJECTIVE: This study investigated the effects of dietary methionine restriction (MR) on the progression of established hepatic steatosis in the leptin-deficient ob/ob mouse. MATERIAL/METHODS: Ten-week-old ob/ob mice were fed diets containing 0.86% (control-fed; CF) or 0.12% methionine (MR) for 14 weeks. At 14 weeks, liver and fat were excised and blood was collected for analysis. In another study, blood was collected to determine in vivo triglyceride (TG) and very-low-density lipoprotein (VLDL) secretion rates. Liver histology was conducted to determine the severity of steatosis. Hepatic TG, free fatty acid levels, and fatty acid oxidation (FAO) were also measured. Gene expression was analyzed by quantitative PCR. RESULTS: MR reversed the severity of steatosis in the ob/ob mouse. This was accompanied by reduced body weight despite similar weight-specific food intake. Compared with the CF group, hepatic TG levels were significantly reduced in response to MR, but adipose tissue weight was not decreased. MR reduced insulin and HOMA ratios but increased total and high-molecular-weight adiponectin levels. Scd1 gene expression was significantly downregulated, while Acadvl, Hadha, and Hadhb were upregulated in MR, corresponding with increased ß-hydroxybutyrate levels and a trend toward increased FAO. The VLDL secretion rate was also significantly increased in the MR mice, as were the mRNA levels of ApoB and Mttp. The expression of inflammatory markers, such as Tnf-α and Ccr2, was also downregulated by MR. CONCLUSIONS: Our data indicate that MR reverses steatosis in the ob/ob mouse liver by promoting FAO, increasing the export of lipids, and reducing obesity-related inflammatory responses.

Asunto(s)

Ácidos Grasos/metabolismo , Hígado Graso/prevención & control , Leptina/deficiencia , Metabolismo de los Lípidos , Hígado/metabolismo , Metionina/administración & dosificación , Metionina/farmacología , Obesidad/metabolismo , Ácido 3-Hidroxibutírico/sangre , Animales , Biomarcadores/sangre , Glucemia/efectos de los fármacos , Glucemia/metabolismo , Dieta , Progresión de la Enfermedad , Hígado Graso/sangre , Hígado Graso/metabolismo , Hígado Graso/patología , Regulación de la Expresión Génica , Homeostasis , Inflamación/etiología , Inflamación/metabolismo , Insulina/metabolismo , Lipoproteínas VLDL/sangre , Masculino , Ratones , Ratones Obesos , Obesidad/sangre , Obesidad/patología , Oxidación-Reducción , Índice de Severidad de la Enfermedad , Triglicéridos/sangre