Beneficial Effects of High-Intensity Interval Training and Dietary Changes Intervention on Hepatic Fat Accumulation in HFD-Induced Obese Rats.

Lifestyle intervention encompassing nutrition and physical activity are effective strategies to prevent progressive lipid deposition in the liver. This study aimed to explore the effect of dietary change, and/or high-intensity interval training (HIIT) on hepatic lipid accumulation in high fat diet (HFD)-induced obese rats. We divided lean rats into lean control (LC) or HIIT groups (LH), and obese rats into obese normal chow diet (ND) control (ONC) or HIIT groups (ONH) and obese HFD control (OHC) or HIIT groups (OHH). We found that dietary or HIIT intervention significantly decreased body weight and the risk of dyslipidemia, prevented hepatic lipid accumulation. HIIT significantly improved mitochondrial fatty acid oxidation through upregulating mitochondrial enzyme activities, mitochondrial function and AMPK/PPARalpha/CPT1alpha pathway, as well as inhibiting hepatic de novo lipogenesis in obese HFD rats. These findings indicate that dietary alone or HIIT intervention powerfully improve intrahepatic storage of fat in diet induced obese rats. Keywords: Obesity, Exercise, Diet, Mitochondrial function, Lipid deposition.

Rab1 in cell signaling, cancer and other diseases.

The endoplasmic reticulum (ER) and Golgi membrane system have major roles in cell signaling and regulation of the biosynthesis/transport of proteins and lipids in response to environmental cues such as amino acid and cholesterol levels. Rab1 is the founding member of the Rab small GTPase family, which is known to mediate dynamic membrane trafficking between ER and Golgi. Growing evidence indicate that Rab1 proteins have important functions beyond their classical vesicular transport functions, including nutrient sensing and signaling, cell migration and presentation of cell-surface receptors. Moreover, deregulation of RAB1 expression has been linked to a myriad of human diseases such as cancer, cardiomyopathy and Parkinson's disease. Further investigating these new physiological and pathological functions of Rab1 should provide new opportunities for better understanding of the disease processes and may lead to more effective therapeutic interventions.

Structure and promoter activity of the LpS1 genes of Lytechinus pictus. Duplicated exons account for LpS1 proteins with eight calcium binding domains.

The LpS1 genes of the sea urchin Lytechinus pictus are activated early in development in aboral ectoderm cells. They therefore have ontogenic properties similar to their counterparts in Stronglyocentrotus purpuratus, the Spec genes. Both gene families encode proteins belonging to the calmodulin superfamily as evidenced by the presence of distinct EF-hand (helix-loop-helix) domains. The presence of eight EF-hand domains in LpS1 proteins suggests that the LpS1 genes arose from a duplication of an ancestral Spec-like gene. The LpS1 genes were further analyzed to increase our understanding of the mechanisms underlying their evolution and activation in aboral ectoderm cells. Genomic DNA blot analysis showed two LpS1 genes, LpS1 alpha and LpS1 beta, which did not appear to be closely linked. LpS1 genomic clones were isolated by screening an L. pictus genomic library with an LpS1 cDNA clone, and partial gene structures for both LpS1 alpha and LpS1 beta were constructed. These revealed internal duplication of the LpS1 genes that accounted for the eight EF-hand domains in the LpS1 proteins. Duplication of exon 1 in both genes suggested four different LpS1 proteins could be derived from the LpS1 genes. Primer extension to map the transcriptional initiation sites of the LpS1 genes and sequencing analysis showed there was little in common among the 5'-flanking regions of the LpS1 and Spec genes except for the presence of a binding site for the transcription factor USF. A sea urchin gene-transfer expression system showed that 762 base pairs (bp) of 5'-flanking DNA and 17 bp of 5'-untranslated leader sequence of the LpS1 beta gene were sufficient for correct temporal and spatial expression of reporter chloramphenicol acetyltransferase and lacZ genes in sea urchin embryos. Deletions at the 5' end to either 511 or 368 bp resulted in a 3-4 fold decrease in chloramphenicol acetyltransferase activity and disrupted the exclusive activation of the lacZ gene in aboral ectodermal cells. Based on a lineage analysis among the LpS1 and Spec gene families and other related genes, we propose a model in which LpS1 genes evolved from a series of duplications of an ancestral Spec-like gene.

Tandem duplication and divergence of a sea urchin protein belonging to the troponin C superfamily.

The Spec1 and Spec2 proteins of the sea urchin Strongylocentrotus purpuratus are related to calmodulin, troponin C, and myosin light chains by sequence similarity in their four calcium binding domains. These domains, the EF-hands, are distinct helix-loop-helix structures of about 40 amino acids. The Spec1 and Spec2 genes are expressed specifically in aboral ectoderm cells of the developing embryo; however, the function of the Spec proteins in these cells is unknown. To find conserved regions of the proteins that might be important for structure and function, Spec homologues from Lytechinus pictus, a distantly related sea urchin, were sought. L. pictus embryos do not synthesize detectable amounts of the 14,000-17,000-Da Spec proteins as determined by two-dimensional gel electro-phoresis, but do synthesize three 34,000-Da proteins that cross-react with Spec1 antibodies and display a similar ontogenetic pattern of expression. cDNA clones were isolated by hybridization to a synthetic oligonucleotide corresponding to the EF-hand. One clone, LpS1, encodes an mRNA with developmental properties like those of the S. purpuratus Spec mRNAs. However, LpS1 contains an open reading frame for a protein of 34,000 Da rather than 17,000 Da, and antibodies raised against part of the LpS1 reading frame demonstrate that LpS1 encodes a 34,000-Da protein in L. pictus embryos. The sequence of LpS1 reveals the presence of eight EF-hand domains, which share structural homology with the Spec1 or Spec2 EF-hands; however, little else in the protein sequence is conserved. The results support the hypothesis that the LpS1 gene arose from a duplication of an ancestral Spec gene and that the overall structural features of the Spec family of proteins are more conserved than the amino acid sequences.