Cell death-inducing DFFA-like effector c (CIDEC/Fsp27) gene: molecular cloning, sequence characterization, tissue distribution and polymorphisms in Chinese cattles

Characterization and expression analysis of seven lipid metabolism-related genes in yellow catfish Pelteobagrus fulvidraco fed high fat and bile acid diet

SREBPs, such as SREBP1 and SREBP2, were the key transcriptional factors regulating lipid metabolism. The processing of SREBPs involved many genes, such as scap, s1p, s2p, cideb. Here, we deciphered the full-length cDNA sequences of scap, srebp1, srebp2, s1p, s2p, cideb and cidec from yellow catfish Pelteobagrus fulvidraco. Their full-length cDNA sequences ranged from 1587 to 3884 bp, and their ORF length from 1191 to 2979 bp, encoding 396-992 amino acids. Some conservative domains were predicted, including the multiple transmembrane domains in SCAP, the bHLH-ZIP domain in SREBP1 and SREBP2, the ApoB binding region, ER targeting region and LD targeting region in CIDEb, the LD targeting region in the CIDEc, the conserved catalytic site and processing site in S1P, and the transmembrane helix domain in S2P. Their mRNA expression could be observed in the heart, spleen, liver, kidney, brain, muscle, intestine and adipose, but varied with tissues. The changes of their mRNA expression in responses to high-fat (HFD) and bile acid (BA) diets were also investigated in the brain, heart, intestine, kidney and spleen tissues. In the brain, HFD significantly increased the mRNA expression of seven genes (scap, srebp1, srebp2, s1p, s2p, cideb and cidec), and the BA attenuated the increase of scap, srebp1, srebp2, s1p, s2p, cideb and cidec mRNA expression induced by HFD. In the heart, HFD significantly increased the mRNA abundances of six genes (srebp1, srebp2, scap, s2p, cideb and cidec), and BA attenuated the increase of their mRNA abundances induced by HFD. In the intestine, HFD increased the cideb, s1p and s2p mRNA abundances, and BA attenuated the HFD-induced increment of their mRNA abundances. In the kidney, HFD significantly increased the scap, cidec and s1p mRNA expression, and BA diet attenuated the increment of their mRNA expression. In the spleen, HFD treatment increased the scap, srebp2, s1p and s2p mRNA expression, and BA diet attenuated HFD-induced increment of their mRNA expression. Taken together, our study elucidated the characterization, expression profiles and transcriptional response of seven lipid metabolic genes, which would serve as the good basis for the further exploration into their function and regulatory mechanism in fish.

Familial partial lipodystrophy syndromes

Lipodystrophies are a heterogeneous group of rare conditions characterised by the loss of adipose tissue. The most common forms are the familial partial lipodystrophy (FPLD) syndromes, which include a set of disorders, usually autosomal dominant, due to different pathogenetic mechanisms leading to improper fat distribution (loss of fat in the limbs and gluteal region and variable regional fat accumulation). Affected patients are prone to suffering serious morbidity via the development of metabolic complications associated to insulin resistance and an inability to properly store lipids. Although no well-defined diagnostic criteria have been established for lipodystrophy, there are certain clues related to medical history, physical examination and body composition evaluation that may suggest FPLD prior to confirmatory genetic analysis. Its treatment must be fundamentally oriented towards the control of the metabolic abnormalities. In this sense, metreleptin therapy, the newer classes of hypoglycaemic agents and other investigational drugs are showing promising results. This review aims to summarise the current knowledge of FPLD syndromes and to describe their clinical and molecular picture, diagnostic approaches and recent treatment modalities.

Distribution and quantitative analysis of CIDEa and CIDEc in broiler chickens: accounting for differential fat deposition between strains

1. Differences in the expression of CIDEa and CIDEc in 20 different tissues were examined. Both CIDEa and CIDEc mRNA transcripts were predominantly but variably expressed in white adipose tissue (WAT) but were also expressed at moderate levels in the kidney and liver and at lower levels in the ovary. Interestingly, among WAT types, both CIDEa and CIDEc were expressed at the lowest levels in heart coronary WAT. 2. To better understand the roles of CIDEa and CIDEc in the fat deposition of broiler chickens, the differences in lipid droplet (LD) size and mRNA levels of CIDEa and CIDEc between lean-type and fat-type broiler chicken lines were studied. LD sizes were larger in fat-type broiler lines, and CIDEa and CIDEc mRNA levels in white adipose, kidney and liver tissues were significantly higher in fat-type broiler lines than in their lean counterparts. 3. Developmental expression patterns of CIDEa and CIDEc mRNA were analysed in different tissue types (WAT, liver and kidney) in Arbor Acres broiler chickens, and CIDEa and CIDEc mRNA expression levels increased during sequential developmental stages, achieving peak expression levels at week 6. 4. These observations suggest that the functions of CIDEa and CIDEc reflect inherent characteristics of lipid metabolism that contribute to the differences in fat deposition between strains. The results in this study contribute to a more robust understanding of the tissue distribution and expression patterns of CIDEa and CIDEc mRNA and facilitate further research concerning the molecular mechanism underlying fat deposition in broiler chickens.

Molecular cloning, genomic organization, chromosome mapping, tissues expression pattern and identification of a novel splicing variant of porcine CIDEb gene

Cell death-inducing DNA fragmentation factor-α-like effector b (CIDEb) is a member of the CIDE family of apoptosis-inducing factors, CIDEa and CIDEc have been reported to be Lipid droplets (LDs)-associated proteins that promote atypical LD fusion in adipocytes, and responsible for liver steatosis under fasting and obese conditions, whereas CIDEb promotes lipid storage under normal diet conditions [1], and promotes the formation of triacylglyceride-enriched VLDL particles in hepatocytes [2]. Here, we report the gene cloning, chromosome mapping, tissue distribution, genetic expression analysis, and identification of a novel splicing variant of the porcine CIDEb gene. Sequence analysis shows that the open reading frame of the normal porcine CIDEb isoform covers 660bp and encodes a 219-amino acid polypeptide, whereas its alternative splicing variant encodes a 142-amino acid polypeptide truncated at the fourth exon and comprised of the CIDE-N domain and part of the CIDE-C domain. The deduced amino acid sequence of normal porcine CIDEb shows an 85.8% similarity to the human protein and 80.0% to the mouse protein. The CIDEb genomic sequence spans approximately 6KB comprised of five exons and four introns. Radiation hybrid mapping demonstrated that porcine CIDEb is located at chromosome 7q21 and at a distance of 57cR from the most significantly linked marker, S0334, regions that are syntenic with the corresponding region in the human genome. Tissue expression analysis indicated that normal CIDEb mRNA is ubiquitously expressed in many porcine tissues. It was highly expressed in white adipose tissue and was observed at relatively high levels in the liver, lung, small intestine, lymphatic tissue and brain. The normal version of CIDEb was the predominant form in all tested tissues, whereas the splicing variant was expressed at low levels in all examined tissues except the lymphatic tissue. Furthermore, genetic expression analysis indicated that CIDEb mRNA levels were significantly higher in the white adipose tissue of lean pigs than their obese counterparts, in contrast to porcine CIDEa and CIDEc [3]. We therefore speculate that CIDEb may play a contrary role to the other CIDEs. The basic molecular information we provide here will be useful for further investigations of the physiological function of the gene, which will be helpful in better understanding the role of the CIDE family in lipid metabolism in pig models.

Comprehensive Transcriptome Analyses of the Fructose-Fed Syrian Golden Hamster Liver Provides Novel Insights into Lipid Metabolism

Dyslipidemia has been widely proven to contribute to cardiovascular diseases and other metabolic disorders, especially in insulin resistance and type 2 diabetes. The overproduction of VLDL is a significant characteristic of dyslipidemia, indicating the dysfunction of hepatic lipid metabolism, from triglyceride synthesis to transport. The fructose-fed Syrian golden hamster is an established animal model for the study of VLDL assembly with insulin resistance, however, it remains unknown how VLDL production is regulated at the transcriptional level due to the absence of a complete hamster genome. Here, we performed deep sequencing and constructed an mRNA-miRNA-lncRNA interaction network of Syrian golden hamster liver in order to reveal the global transcription profile and find potential RNA molecular regulation of VLDL production. We identified 4,450 novel multi-exon hamster lncRNAs and 755 miRNAs expressed in liver. Additionally, 146 differentially expressed coding genes, 27 differentially expressed lncRNA genes, as well as 16 differentially expressed miRNAs were identified. We then constructed an mRNA-miRNA-lncRNA interaction network that may potentially regulate VLDL production, and interestingly found several microRNA-centered regulatory networks. In order to verify our interpretation, miR-486 was selected for further experiments. Overexpression or down-regulation of miR-486 in fructose-fed hamsters resulted in altered hepatic expression of proteins involved in VLDL production, and in modulated levels of circulating VLDL. Our findings implicated that miR-486 is a potential regulator of circulating VLDL levels. These results provide new insights and a valuable resource for further study of the molecular mechanisms of VLDL secretion.