Broadband radar absorbing metamaterial based on Al @SiO2 conductive composite film.

Artificially designed metamaterial structures can manipulate electromagnetic waves, endowing them with exotic physical properties that are not found in natural materials, such as negative refractive index, superlens, and inverse Doppler effect. These characteristics are widely applied in various engineering and military applications. Due to increasingly complex application environments and innovation in radar detection technology, the combination of broadband absorption performance under thin thickness and efficient preparation methods at low cost is often the focus of research on new generation stealth materials. Here, we propose Al@SiO2 composite conductive film metamaterial (Al@SiO2 CCFM) to achieve wideband absorption of electromagnetic waves. This metamaterial structure combines two resonant units, resulting in three absorption bands in the absorption curve. The results show that the absorption rate of the metamaterial is above 90% in the frequency range of 10.6 GHz to 26.0 GHz. The resonance mechanism between multiple structures is a prerequisite for achieving wideband absorption. The materials Al and SiO2 used in Al@SiO2 CCFM are inexpensive and abundant, and the fabrication method is simple. Therefore, they hold great potential for large-scale applications in the multispectral stealth and electromagnetic shielding field.

FTO promotes SREBP1c maturation and enhances CIDEC transcription during lipid accumulation in HepG2 cells.

The fat mass and obesity-associated (FTO) gene is tightly related to body weight and fat mass, and plays a pivotal role in regulating lipid accumulation in hepatocytes. However, the mechanisms underlying its function are poorly understood. Sterol regulatory element binding protein-1c (SREBP1c) is a transcription factor that regulates lipogenesis. Cell death-inducing DFFA (DNA fragmentation factor-α)-like effector c (CIDEC) plays a crucial role in lipid droplets (LDs) size controlling and lipid accumulation. In this report, we first observed that FTO overexpression in HepG2 cells resulted in an increase of lipogenesis and up-regulation of SREBP1c and CIDEC, two key regulatory factors in lipogenesis. In contrast, FTO knockdown in HepG2 cells resulted in a decrease of lipogenesis and down-regulation of SREBP1c and CIDEC expression. Moreover, SREBP1c knockdown resulted in a decrease of lipogenesis in HepG2 cells with FTO overexpression. In addition, FTO demethylation defect mutant presented less transcription of the key genes, and less nuclear translocation and maturation of SREBP1c. Further investigation demonstrated that overexpression of SREBP1c in HepG2 cells also promoted high CIDEC expression. Luciferase reporter assays showed that SREBP1c significantly stimulated CIDEC gene promoter activity. Finally, CIDEC knockdown reduced SREBP1c-induced lipogenesis. In conclusion, our studies suggest that FTO increased the lipid accumulation in hepatocytes by increasing nuclear translocation of SREBP1c and SREBP1c maturation, thus improving the transcriptional activity of LD-associated protein CIDEC. Our studies may provide new mechanistic insight into nonalcoholic fatty liver disease (NAFLD) mediated by FTO.

Macrophage migration inhibitory factor in the regulation of myoblast proliferation and differentiation.

Obesity is documented to be a state of chronic mild inflammation associated with increased macrophage infiltration into adipose tissue and liver and skeletal muscle. As a pleiotropic inflammatory mediator, macrophage migration inhibitory factor (MIF) is associated with metabolic disease, so MIF may signal molecular links between adipocytes and myocytes. MIF expression was modified during myoblast differentiation, but the role of MIF during this process is unclear. C2C12 cells were transfected with MIF to investigate their role during differentiation. MIF expression attenuated C2C12 differentiation. It did not change proliferation, but downregulated cyclin D1 and CDK4, causing cell accumulation in the G1 phase. p21 protein was increased significantly and MyoD, MyoG, and p21 mRNA also increased significantly in the C2C12 cells treated with ISO-1, suggesting that inhibition of MIF promotes differentiation. MIF inhibits the myoblast differentiation by affecting the cell cycle progression, but does not affect proliferation.

Adipose induces myoblast differentiation and mediates TNFα-regulated myogenesis.

Skeletal muscle formation is controlled by multiple processes. These processes are tightly regulated by muscle regulatory factors. Genes that are highly and specifically expressed during myogenesis need to be identified. In the present study, the role of an anti-adipogenic gene adipose (Adp) in myogenesis is demonstrated. We discover that the expression of Adp is increased during myoblast differentiation. Overexpression of Adp in mouse myoblast C2C12 cells leads to an increase of myogenesis and up-regulation of MyoG expression. The inhibition effect of tumor necrosis factor α (TNFα) on myogenic differentiation is reversed by Adp-overexpression. Further research showed that TNFα significantly decreases Adp expression at both the mRNA and protein levels. Luciferase reporter assays showed that TNFα can inhibit Adp gene promoter activity and impair gene transcription. KLF15 was found to regulate the transcription of Adp. Furthermore, the expression of KLF15 and its binding to Adp promoter were reduced due to TNFα treatment. The reduced KLF15 expression after TNFα treatment is responsible for the repression of Adp gene promoter activity. KLF15 was also found to participate in Adp-mediated myogenic differentiation. Taken together, these data identify Adp as a positive modulator of myoblast differentiation and provide new insights for Adp function research.

Translocation of CIDEC in hepatocytes depends on fatty acids.

The CIDEC protein is located in lipid droplets (LDs) and the endoplasmic reticulum (ER) and is induced in fat deposition. However, the binding domain, the functional domain and the underlying mechanism of CIDEC in stimulating lipid accumulation remain unclear. Here, we investigated the subcellular localization and function of pig CIDEC and confirmed CIDEC promotes unilocular development of LDs, reduces the specific surface area (SSA) of LDs and stimulates lipid accumulation in HepG2 cells. By analyzing a series of CIDEC mutants, we showed the N-domain (1-173 amino acid) is involved in LD localization and the C-domain (174-238 amino acid) is necessary for LD fusion. Further analysis indicated that the 106-173 amino acid region includes an ER-binding domain. Moreover, CIDEC stayed in the ER under lipid-deficient conditions and translocated to LDs under fatty acid stimulation suggesting that localization of CIDEC in the ER is before the LD. Our data indicated additional fatty acids stimulated hepatic CIDEC expression and an increasing level of CIDEC induced hepatic LD fusion and lipid accumulation. Our work suggests that CIDEC protects LDs by decreasing the SSA of LDs and is involved in the regulation of hepatic lipid deposition.

Resistin Increases Ectopic Deposition of Lipids Through miR-696 in C2C12 Cells.

Resistin is associated with ectopic deposition of lipids, and determining its developmental and molecular mechanisms may help in the development of novel treatments. MicroRNAs (miRNAs) are involved in many physiological and pathological processes as negative regulators. We performed mouse liver miRNA microarrays to analyze the differences in expression between resistin-treated and control mice; the results showed that miR-696 was significantly upregulated by resistin. Therefore, we aimed to study whether miR-696 played a role in the resistin-induced ectopic deposition of lipids. Quantitative RT-PCR results showed that miR-696 was upregulated both in vivo and in vitro, consistent with the microarray. We transfected C2C12 cells and used miR-696 mimics and inhibitors to assess the role of miR-696 in the resistin-induced ectopic deposition of lipids. The overexpression of miR-696 increased the TG content in C2C12 cells and decreased the mitochondrial content. Next, a study of miR-696's role in the deposition of lipids in C2C12 induced by resistin showed that inhibition of miR-696 restored the TG content by up to 80%, which suggests that, in C2C12 cells, resistin at least partially increases the deposition of lipids through miR-696. miR-696 plays a role in the ectopic deposition of lipids induced by resistin in skeletal muscle at least partially.

MiRNA-145 is involved in the development of resistin-induced insulin resistance in HepG2 cells.

BACKGROUND: Resistin is associated with insulin resistance, and determining its developmental and molecular mechanisms may help the development of novel treatments. MicroRNAs (miRNAs) are involved in many physiological and pathological processes as negative regulators. However, it remains unclear whether miRNAs play a role in resistin-induced insulin resistance. We performed mouse liver miRNA microarrays to analyze the differences in expression between resistin-treated and control mice. Resistin upregulated miR-145 both in vivo and in vitro. Therefore, we aimed to study whether miR-145 played a role in resistin-induced insulin resistance. METHODS AND RESULTS: We transfected HepG2 cells, and used miR-145 mimics and inhibitors to assess the role of miR-145 in resistin-induced insulin resistance. The overexpression of miR-145 inhibited glucose uptake in HepG2 cells, diminished the phosphorylation of Akt and IRS-1, and induced insulin resistance in hepatocytes. Next, a study of transcriptional regulation revealed that p65 was essential for the upregulation of miR-145 by resistin, and chromatin immunoprecipitation (ChIP) confirmed that p65 could bind to the promoter region of miR-145. CONCLUSION: miR-145 plays a role in the development of resistin-induced insulin resistance via the p65 pathway.

Resistin reduces mitochondria and induces hepatic steatosis in mice by the protein kinase C/protein kinase G/p65/PPAR gamma coactivator 1 alpha pathway.

UNLABELLED: Obesity is associated with many severe chronic diseases and deciphering its development and molecular mechanisms is necessary for promoting treatment. Previous studies have revealed that mitochondrial content is down-regulated in obesity, diabetes, and nonalcoholic fatty liver disease (NAFLD) and proposed that NAFLD and diabetes are mitochondrial diseases. However, the exact mechanisms underlying these processes remain unclear. In this study, we discovered that resistin down-regulated the content and activities of mitochondria, enhanced hepatic steatosis, and induced insulin resistance (IR) in mice. The time course indicated that the change in mitochondrial content was before the change in fat accumulation and development of insulin resistance. When the mitochondrial content was maintained, resistin did not stimulate hepatic fat accumulation. The present mutation study found that the residue Thr464 of the p65 subunit of nuclear factor kappa B was essential for regulating mitochondria. A proximity ligation assay revealed that resistin inactivated peroxisome proliferator activated receptor gamma coactivator 1 alpha (PGC-1α) and diminished the mitochondrial content by promoting the interaction of p65 and PGC-1α. Signaling-transduction analysis demonstrated that resistin down-regulated mitochondria by a novel protein kinase C/protein kinase G/p65/PGC-1α-signaling pathway. CONCLUSION: Resistin induces hepatic steatosis through diminishing mitochondrial content. This reveals a novel pathway for mitochondrial regulation, and suggests that the maintenance of normal mitochondrial content could be a new strategy for treatment of obesity-associated diseases.

TNF-α reduces g0s2 expression and stimulates lipolysis through PPAR-γ inhibition in 3T3-L1 adipocytes.

Tumor necrosis factor-α (TNF-α) is a multifunctional cytokine that acts as a mediator of obesity-linked insulin resistance (IR). It is commonly accepted that macrophage-derived TNF-α acts in a paracrine manner on adjacent adipocytes, induces lipolysis, which contributes to obesity-linked hyperglycemia. Several studies suggested that G0/G1 switch gene 2 (g0s2) was up-regulated during adipogenesis, and its protein could be degraded in response to TNF-α stimulation. The aim of the present work was to investigate the transcriptional regulation of g0s2 by TNF-α stimulation. In this study, 3T3-L1 pre-adipocytes were differentiated, and treated with TNF-α for 24h. The effects of TNF-α on lipolysis and lipase expression were then examined. Our results revealed that TNF-α exerted dose- and time-dependent lipolytic effects, which could be partially reversed by overexpression of g0s2 and peroxisome proliferator-activated receptor-γ (ppar-γ). In addition, TNF-α treatment significantly reduced the expression of adiponectin, ppar-γ, hormone-sensitive Lipase (hsl), adipose triglyceride lipase (atgl) as well as ATGL co-factors. Interestingly, TNF-α significantly decreased adiponectin and PPAR-γ protein levels, while treatment with the proteasomal inhibitor MG-132 maintained PPAR-γ levels. Degradation of PPAR-γ almost completely abolished the binding of PPAR-γ to the g0s2 promoter in adipocytes treated with TNF-α. We propose that proteasomal degradation of PPAR-γ and the reduction of g0s2 content are permissive for prolonged TNF-α induced lipolysis.

Genetic variability of MHC class II DQB exon 2 alleles in yak (Bos grunniens).

The major histocompatibility class (MHC) DQ molecules are dimeric glycoproteins revealing antigen presentation to CD(4+) T cells. In the present study, the exon 2 of the MHC class II DQB gene from 32 yaks (Bos grunniens) was cloned, sequenced and compared with previously reported patterns for other bovidae. It was revealed by sequence analyses that there are 25 DQB exon 2 alleles among 32 yaks, all alleles are found to belong to DQB1 loci. These alleles exhibited a high degree of nucleotide and amino acid polymorphisms with most amino acid variations occurring at positions forming the peptide-binding sites. The DQB loci were analyzed for patterns of synonymous (d S) and non-synonymous (d N) substitution. The yak was observed to be under strong positive selection in the DQB exon 2 peptide-binding sites (d N = 0.15, P < 0.001). It appears that this variability among yaks confers the ability to mount immune responses to a wide variety of peptides or pathogens.

Primary study on the effects and mechanisms of separate and combined decoctions of Scutellaria baicalensis Georgi - Coptis chinensis Franch extracts in relieving acute alcoholic liver injury in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Scutellaria baicalensis Georgi (SBG) and Coptis chinensis Franch (CCF) are traditional herbal medicine pairs used for clearing heat and eliminating dampness, stopping diarrhea, and detoxification. Traditionally, these two herbs are combined and decocted together, but the modern preparation procedures separate them to avoid the large amount of precipitation generated from co-decoction. Thus, a conflict lies between the traditional and modern extraction processes of Scutellaria baicalensis Georgi - Coptis chinensis Franch (SBG-CCF). AIM OF STUDY: There is a conflict between traditional medical practices of SBG-CCF and the modern formulation industry. In this study, we investigated the differences in the effects and mechanisms of SBG-CCF extracted by decocting separately and combining decoctions, as well as the scientific effectiveness of traditional and modern treatment methods on both. Acute alcoholic liver injury (ALI) rats were used as the pathological model. MATERIALS AND METHODS: SD rats were divided into 8 groups, including blank group, model group, low, medium, and high dose groups of SBG-CCF separated decoction, low, medium, and high dose groups of SBG-CCF combined decoction. Acute alcoholic liver injury model was induced in rats by gradually increasing the dose of alcohol through gavage everyday using white wine with an alcohol content 52%. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol (TC), triglyceride (TG), lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD), and reduced glutathione (GSH) were used as indicators to assess the intervention effect of SBG-CCF. And the potential active ingredients of SBG-CCF and the targets related to ALI were screened using network pharmacology, and the prediction results of network pharmacology were verified by quantitative real-time fluorescence PCR (qRT-PCR). RESULTS: SBG-CCF decoction alone and six combinations of decoctions have different degrees of improvement on alcoholic liver injury, with significant efficacy in the middle-dose group, and the combined decoction was superior to the individual decoction. SBG-CCF gavage can reduce the activity of AST, ALT, TC, TG, LDH, and MDA in the serum and liver of ALI rats, while increasing the levels of SOD and GSH. Network pharmacological analysis identified 39 active components, mainly flavonoids and alkaloids. Enrichment analysis suggested that SBG-CCF may treat ALI through the regulation of tumor necrosis factor (TNF), mitogen-activated protein kinase (MAPK), interleukin-17 (IL-17), apoptosis, and the Toll-like receptor signaling pathways. The key targets in the Disease-Signaling Pathway-Target Network were MAPK8, IKBKB, MAPK10, MAPK3, MAPK1, and AKT1. qRT-PCR results indicated that targets regulating inflammation and lipid metabolism are MAPK8, MAPK10, MAPK3, and AKT1. CONCLUSION: SBG-CCF separately extracts and combines decoction can alleviate acute alcoholic liver injury, and the effect of combined decoction is more significant than separate decoction, implying that the precipitate produced by the combination of the two is also an active substance. The resistance mechanism of SBG-CCF ALI may be related to the modulation of lipid metabolism, inhibition of lipid peroxidation, and oxidative stress. SBG-CCF has the characteristics of multi-component, multi-pathway, and multi-target resistance to ALI.

Activation of Liver X receptors in the heart leads to accumulation of intracellular lipids and attenuation of ischemia-reperfusion injury.

Liver X receptor (LXR)-α and -ß play a major role in lipid and glucose homeostasis. Their expression and function in the heart is not well characterized. Our aim was to describe the expression of LXRs in the murine heart, and to determine effects of cardiac LXR activation on target gene expression, lipid homeostasis and ischemia. Both LXRα and -ß were expressed in heart tissues, HL-1 cells and isolated cardiomyocytes as determined by qRT-PCR. Elevated cardiac expression of LXR target genes and LXRß was observed 24 h after in vivo permanent coronary artery ligation. The synthetic LXR agonist GW3965 induced mRNA expression of the LXR target genes in HL-1 cells and isolated cardiomyocytes. This was associated with a buildup of intracellular triglycerides and expanding lipid droplets as quantified by confocal microscopy. Mice injected with GW3965 had cardiac LXR activation as judged by increased target gene expression and lipid droplet accumulation. GW3965 in vivo and in vitro increased expression of genes inducing triglyceride synthesis, and altered expression of lipid droplet-binding protein genes. GW3965 protected HL-1 cells against hypoxia-reoxygenation induced apoptosis. LXR activation by GW3965 in vivo prior to heart isolation and perfusion with induced global ischemia and reperfusion improved left ventricular contractile function and decreased infarct size. In conclusion, LXRs are expressed in the murine heart in the basal state, and are activated by myocardial infarction. Activation of LXR by the synthetic agonist GW3965 is associated with intracardiac accumulation of lipid droplets and protection against myocardial ischemia-reperfusion injury.

Adipose improves muscular atrophy caused by Sirtuin1 deficiency by promoting mitochondria synthesis.

Muscular dysplasia is a common muscle disease, but its pathological mechanism is still unclear. Adipose is originally identified as a highly conservative and widely expressed anti-obesity gene, and our previous study has reported that Adipose is also a positive regulator of myogenesis. Considering the vital role of during muscle development, this study was to demonstrate a potential relationship between Sirtuin1 and Adipose and clarified the mechanism by which Adipose regulated muscle development. Our results showed that the muscle fiber cross-sectional area and myosin heavy chain protein level were significantly reduced in Sirtuin1+/- mice. Moreover, the longitudinal section of muscle fibers was obviously irregular. Sirtuin1 knockdown significantly reduced the expression levels of Adipose and its upstream transcriptional regulator Kruppel like factor 15 and notably inhibited the AMP-activated protein kinase α-peroxisome proliferator-activated receptor gamma coactivator 1α signaling pathway in skeletal muscle. However, Adipose over-expression activated this signaling pathway and promoted mitochondrial biosynthesis in C2C12 myoblasts. Adipose over-expression also enhanced glucose absorption of C2C12 cells, suggesting the increased needs for cells for metabolic substrates. In C2C12 cells with hydrogen peroxide treatment, Adipose over-expression repressed hydrogen peroxide-elicited apoptosis and mitochondrial loss, while Sirtuin1-specific inhibitor dramatically weakened these roles of Adipose. Taken together, our findings reveal that Adipose rescues the adverse effects of Sirtuin1 deficiency or hydrogen peroxide on muscle development by activating the AMP-activated protein kinase α- peroxisome proliferator-activated receptor gamma coactivator 1α pathway to promote mitochondria synthesis, which provides theoretical basis for developing new therapeutic targets against some muscle diseases.

Peroxidative depolymerization of fucosylated glycosaminoglycan: Bond-cleavage pattern and activities of oligosaccharides.

Peroxidative depolymerization is often used to elucidate the structure and structure-activity relationship of fucosylated glycosaminoglycan (FG), while the selectivity of bond cleavage and structural characteristics of the resulting fragments remain to be confirmed. Here, the FG from Stichopus variegatus (SvFG) was depolymerized by H2O2, and a series of yielded mono- and oligo-saccharides were purified. Almost all the non-reducing ends of oligosaccharides were d-GalNAc4S6S, suggesting that GlcA-ß1,3-GalNAc4S6S linkage was preferentially cleaved. The model reactions showed the glycosidic bond of uronate was more susceptible than those of N-acetyl hexosamine and fucose, which should be due to bond energy of the anomeric CH. The reducing ends of oligosaccharides include C4-C6 saccharic acid and GalNAc or GalNAcA, which should be derived from the oxidation of the reducing end. A hexasaccharide with tartaric acid exhibited increased anti-iXase activity, suggesting the oxidation of reducing end did not impair the anti-iXase activity of FG-derived oligosaccharides.

Identification of alternatively spliced Dab1 and Fyn isoforms in pig.

BACKGROUND: Disabled-1 (Dab1) is an adaptor protein that is essential for the intracellular transduction of Reelin signaling, which regulates the migration and differentiation of postmitotic neurons during brain development in vertebrates. Dab1 function depends on its tyrosine phosphorylation by Src family kinases, especially Fyn. RESULTS: We have isolated alternatively spliced forms of porcine Dab1 from brain (sDab1) and liver (sDab1-Li) and Fyn from brain (sFyn-B) and spleen (sFyn-T). Radiation hybrid mapping localized porcine Dab1 (sDab1) and Fyn (sFyn) to chromosomes 6q31-35 and 1p13, respectively. Real-time quantitative RT-PCR (qRT-PCR) demonstrated that different isoforms of Dab1 and Fyn have tissue-specific expression patterns, and sDab1 and sFyn-B display similar temporal expression characteristics in the developing porcine cerebral cortex and cerebellum. Both sDab1 isoforms function as nucleocytoplasmic shuttling proteins. It was further shown that sFyn phosphorylates sDab1 at tyrosyl residues (Tyr) 185, 198/200 and 232, whereas sDab1-Li was phosphorylated at Tyr 185 and Tyr 197 (corresponding to Y232 in sDab1) in vitro. CONCLUSIONS: Alternative splicing generates natural sDab1-Li that only carries Y185 and Y197 (corresponding to Y232 in sDab1) sites, which can be phosphorylated by Fyn in vitro. sDab1-Li is an isoform that is highly expressed in peripheral organs. Both isoforms are suggested to be nucleocytoplasmic shuttling proteins. Our results imply that the short splice form sDab1-Li might regulate cellular responses to different cell signals by acting as a dominant negative form against the full length sDab1 variant and that both isoforms might serve different signaling functions in different tissues.

Molecular cloning and characterization of the porcine Ero1L and ERp44 genes: potential roles in controlling energy metabolism.

Disulfide bond formation is a pivotal step in the maturation and release of secretory proteins that is controlled by specific endoplasmic reticulum (ER) resident enzymes. An important element in this process is Ero (ER oxidoreduction), a glycosylated flavoenzyme tightly associated with oxidative protein folding that lacks the known ER retention motifs. ER resident protein 44kDa (ERp44) is an ER resident protein that mediates ERo1 localization in ER and also prevents the secretion of unassembled cargo proteins with unpaired cysteine. These proteins are not only the key participants in the disulfide-bond formation process, but they also control the secretory pathway on both qualitative and quantitative levels. Here, we cloned full-length cDNA sequences of the porcine Ero1L (1448bp) and ERp44 (1361bp) genes. Isolation and characterization of their genomic sequences revealed that Ero1L contains 16 exons and 15 introns almost 150 kp in length, whereas ERp44 contains 12 exons and 11 introns more than 140 kp in length, and they are located on porcine chromosome 1q21 and 1q29, respectively. Tissue distribution analysis of the two genes revealed extremely high expression in adipose tissue, and the topology of their phylogenic tree indicates a high degree of conservation among different species. We looked at transcription factors binding sites in the 5'-flanking regions of Ero1L and ERp44, and many adipose differentiations related factors reflect the tight relationship to energy metabolism.

Molecular characterization, expression and chromosomal localization of porcine PNPLA3 and PNPLA4.

Patatin-like phospholipases (PNPLAs) comprise a protein family whose members contain a conserved patatin-like domain with lipid acyl hydrolase activity. The cloning and characterization of full-length cDNAs of PNPLA3 and PNPLA4 in pigs is reported and, for the first time, an alternative splicing variant of porcine PNPLA4, which skips exon 5 of the normal transcript, was identified. Subsequently, tissue expression analysis by quantitative PCR indicated that porcine PNPLA3 was mainly expressed in both adipose and liver whereas porcine PNPLA4 was abundant in liver. Porcine PNPLA3 and PNPLA4 were assigned respectively to chromosome 5p11-p15 and Xp24.

Porcine KLF gene family: Structure, mapping, and phylogenetic analysis.

The Kruppel-like factors (KLFs) belong to the family of zinc finger-containing transcription factors that regulates a diverse array of cellular processes, including cell proliferation, differentiation, and apoptosis. Here we reported the structure, mapping and phylogenetic analysis of KLF gene family in pigs. Comparative analyses revealed strong conservation between pig and human KLFs at the genomic and protein structure levels. Porcine KLF 1-17 were dispersedly located on chromosomes 1, 2, 3, 4, 6, 7, 8, 10, 11, 15, 18 and X, respectively. Based on the phylogenetic analysis, we proposed that KLFs have undergone extensive expansion over the course of evolution. Finally, we identified a characteristic motif in KLF zinc finger domains that can be used to accurately predict potential KLF proteins. The current work represents the first comprehensive study of KLF genes in pigs and provides a foundation for future studies concerning structural, functional, and evolutionary analyses of KLF gene family.

Chemerin causes lipid metabolic imbalance and induces passive lipid accumulation in human hepatoma cell line via the receptor GPR1.

AIMS: Chemerin is abundant in patients with high body mass index and metabolic syndrome possibly due to its activation in adipogenesis and glucose intolerance. It has reported that sera chemerin is positively associated with fatty liver with little known underlying mechanisms. Our aim is to study the role of chemerin in hepatic lipid metabolism. MAIN METHODS: Oil Red O staining and TG quantitative assay were used to detect intracellular lipid accumulation. PCR, QPCR and western blot were applied to measure lipid metabolism-related genes, CMKLR1, GPR1 and inflammation marker genes. Luciferase reporter assay was employed to uncover the down-regulation of proximate promoter activities of CMKLR1 and GPR1 by SREBP1c. Antibody neutralization assay was used to address the effects of chemerin on hepatic lipid synthesis. KEY FINDINGS: Over-expression of chemerin led to passive lipid accumulation, in human hepatoma cell line HepG2. The disable form of chemerin (chemerin 21-158) and active chemerin (chemerin 21-157) performed strongly effects on lipid metabolism in HepG2 cells. Heterologous expression of CMKLR1 or G-protein coupled receptor1 (GPR1) played similar roles in hepatocyte lipid metabolism as chemerin. Chemerin exerted its effects on lipid metabolism via GPR1 in HepG2 cells. Furthermore, free fatty acids and high concentration insulin inhibited chemerin expression. Consistently, the key lipogenic transcription factor Sterol regulatory element binding protein 1c suppressed chemerin mRNA expression and proximate promoter activities of CMKLR1 and GPR1. SIGNIFICANCE: It implied the existence of negative feed-back regulation and further confirmed the involvement of chemerin in hepatic lipid metabolism.

Adiponectin promotes myogenic differentiation via a Mef2C-AdipoR1 positive feedback loop.

Adiponectin is an important hormone that regulates systemic metabolism, and it has been reported that globular adiponectin promotes myogenic differentiation. However, the mechanisms by which adiponectin promotes myogenic differentiation is not fully understood. In the present study, we show that adiponectin and its receptor 1 are significantly up-regulated during myogenic differentiation and that adiponectin increased the expression level of a core myogenic regulator, Mef2C, which is required for the effects of adiponectin on promoting myogenic differentiation. A transcriptional inhibitor of Mef2C, HDAC9, was down-regulated by adiponectin. In turn, Mef2C overexpression up-regulates adiponectin and its receptor, AdipoR1, to increase myogenic differentiation. We showed that mechanistically, Mef2C directly binds to AdipoR1 promoter to transcriptionally up-regulate AdipoR1 expression, which is required for the effects of Mef2C overexpression on myogenic differentiation. Thus, adiponectin/AdipoR1 and Mef2c form a positive feedback loop to promote myogenic differentiation.