Leptin, a cytokine predominantly secreted from fat tissue, plays an important role in regulating organism energy balance. Leptin can stimulate lipolysis, but the mechanism is unclear. In order to study the molecular mechanism of leptin stimulating lipolysis, we systemically studied the mRNA expression of key lipolytic enzymes. Morphological observation, Oil Red O staining and RT-PCR were used to identify pig primary adipocytes; commercial kits were used to measure the glycerol and FFA release; Semiquantitative RT-PCR was used to detect the mRNA expression of key lipolytic enzymes. The results showed that 100 nmol/L leptin up-regulated the mRNA expression of ATGL, TGH-2, HSL, MGL and LPL (P<0.01), but down-regulated the Perilipin mRNA expression (P<0.01). At the same time, leptin promoted the glycerol release in a dose dependent manner (P<0.01), but had no effect on the FFA release (P>0.05). These indicate that leptin may mainly stimulate lipolysis in pig primary adipocytes by up-regulating the expression of ATGL, MGL, LPL and down-regulating the expression of Perilipin. The unchanged FFA release may be resulted from Leptin promoting UCPs mRNA expression and increasing FFA expenditure.
Adipocytes ; cytology ; enzymology ; metabolism ; Animals ; Animals, Newborn ; Cells, Cultured ; Leptin ; pharmacology ; Lipase ; genetics ; metabolism ; Lipolysis ; drug effects ; Male ; Monoacylglycerol Lipases ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Swine

We investigated the prevalence and characteristics of variants of five lipolysis-related genes in Korean patients with very high triglycerides (TGs). Twenty-six patients with TG levels >885 mg/dL were selected from 13545 Korean subjects. Five candidate genes, LPL, APOC2, GPIHBP1, APOA5, and LMF1, were sequenced by targeted next-generation sequencing. Predictions of functional effects were performed and matched against public databases of variants. Ten rare variants of three genes were found in nine (34.6%) patients (three in LPL, four in APOA5, and three in LMF1). Five were novel and all variants were suspected of being disease-causing. Nine were heterozygous, and one (3.8%) had a homozygous rare variant of LPL. Six common variants of four genes were observed in 25 (96.2%) patients (one in LPL, one in GPIHBP1, two in APOA5, and two in LMF1). The c.G41T variant of GPIHBP1 and c.G533T variant of APOA5 were most frequent and found in 15 (57.7%) and 14 (53.8%) patients, respectively. Rare homozygous variants of the genes were very uncommon, while diverse rare heterozygous variants were commonly identified. Taken together, most study subjects may be manifesting the combined effects of rare heterozygous variants and common variants.
Apolipoprotein A-V ; Asian Continental Ancestry Group/genetics ; Female ; Genetic Association Studies ; Genetic Variation ; Heterozygote ; Humans ; Lipolysis/genetics ; Male ; Middle Aged ; Triglycerides/blood

We used CRISPR/Cas9 to delete plin1 of 3T3-L1 preadipocyte, to observe its effect on lipolysis in adipocytes and to explore regulatory pathways. We cultured 3T3-L1 preadipocytes, and the plin1 knockout vectors were transfected by electroporation. Puromycin culture was used to screen successfully transfected adipocytes, and survival rates were observed after transfection. The optimized "cocktail" method was used to differentiate 3T3-L1 preadipocytes. The glycerol and triglyceride contents were determined by enzymatic methods. The changes in lipid droplet form and size were observed by Oil red O staining. The protein expression of PLIN1, PPARγ, Fsp27, and lipases was measured by Western blotting. RT-PCR was used to measure the expression of PLIN1 and lipases mRNA. After the adipocytes in the control group were induced to differentiate, the quantity of tiny lipid droplets was decreased, and the quantity of unilocular lipid droplets was increased and arranged in a circle around the nucleus. Compared with the control group, the volume of unilocular lipid droplets decreased, and the quantity of tiny lipid droplets increased after induction of adipocytes in the knockout group. The expression of PLIN1 mRNA and protein in the adipocytes was significantly inhibited (P<0.05); glycerol levels increased significantly (0.098 4±0.007 6), TG levels decreased significantly (0.031 0±0.005 3); mRNA and protein expression of HSL and ATGL increased (P<0.05); PPARγ and Fsp27 expression unchanged in adipocytes. The above results indicate that the knockout of plin1 enhances the lipolysis of 3T3-L1 adipocytes by exposing lipids in lipid droplets and up-regulating lipases effects.
3T3-L1 Cells ; Adipocytes ; metabolism ; Animals ; CRISPR-Cas Systems ; Gene Knockout Techniques ; Lipase ; metabolism ; Lipolysis ; genetics ; Mice ; Perilipin-1 ; genetics ; metabolism

OBJECTIVEIn order to investigate the possible mechanism of its function to degrade lipid, we detect the effects of hawthorn flavanone to the influence on blood-fat levels and adipogenesis genes transcription expression in fat and muscle tissue of hyperlipoidemia mouse.

METHODIn this experiment, a total of 48 mouse were randomised to four groups and irrigated with two different concentrations (1.5 g kg(-1) body weight and 3.0 g kg(-1) body weight) of hawthorn flavanone, and killed in 0 h, 1 h, 2 h and 4 h. To estimate the content of TC, TG and HCL-C in blood: Total RNA was isolated from adipose and muscle, Real-time RT-PCR was used to analyze expression changes of adipogenesis genes (SREBP-1c, FAS, HSL and TGH) with time series; to analyze the correlation between TG in blood and some kinds of adipogenesis genes and the ratio of FAS/HARMEAN (HSL, TGH) mRNA in adipose.

RESULTHawthorn flavanone was able to cut down the level ofTC, TG and HDL significantly in blood and achieved the lowest level at 1 h. In adipose tissue, hawthorn flavanone up-regulated FAS, HSL and TGH, and achieved the level of significance (P<0.05), the expression level of FAS and TGH was ascend after 1 h, but HSL descend. The expression level of SREBP-1c was descend rapidly and achieved the level of significance after treating with hawthorn flavanone at 1 h (P<0.05), after that it rise again to even higher than the level of before treatment. After treating with hawthorn flavanone, the ratio of FAS/HARMEAN (HSL, TGH) in adipose was significantly descend and achieved the lowest level at 1 h (P<0.01), but it was descendsubsequently. In muscle tissue, hawthorn flavanone was able to significantly up-regulated the expression of FAS and HSL and lower dose group showed greater increasing, the change of SREBP-1c was similar in adipose tissue except the more heavily upgrade.

CONCLUSIONHawthorn flavanone had the function of depressing the concentration of blood-fat, it co-adjusted lipid metabolism of animal by regulating the transcription expression of FAS, HSL, TGH and SREBP-1c especially HSL and SREBP-1c transcription level.

Adipose Tissue ; drug effects ; metabolism ; Animals ; Crataegus ; chemistry ; Flavanones ; pharmacology ; Gene Expression Regulation ; drug effects ; Hyperlipidemias ; blood ; genetics ; Lipids ; blood ; Lipogenesis ; drug effects ; Lipolysis ; drug effects ; genetics ; Male ; Mice ; RNA, Messenger ; genetics ; metabolism ; Sterol Regulatory Element Binding Protein 1 ; genetics ; Triglycerides ; blood ; Up-Regulation ; drug effects ; fas Receptor ; genetics

Higher levels of body fat are associated with an increased risk for development numerous adverse health conditions. FTY720 is an immune modulator and a synthetic analogue of sphingosine 1-phosphate (S1P), activated S1P receptors and is effective in experimental models of transplantation and autoimmunity. Whereas immune modulation by FTY720 has been extensively studied, other actions of FTY720 are not well understood. Here we describe a novel role of FTY720 in the prevention of obesity, involving the regulation of adipogenesis and lipolysis in vivo and in vitro. Male C57B/6J mice were fed a standard diet or a high fat diet (HFD) without or with FTY720 (0.04 mg/kg, twice a week) for 6 weeks. The HFD induced an accumulation of large adipocytes, down-regulation of phosphorylated AMP-activated protein kinase alpha (p-AMPKalpha) and Akt (p-Akt); down-regulation of hormone-sensitive lipase (HSL), adipose triglyceride lipase (ATGL) and perilipin mRNA as well as up-regulation of phosphorylated HSL (p-HSL, Ser563) and glycogen synthase kinase 3 alpha/beta (p-GSK3alpha/beta). All these effects were blunted by FTY720 treatment, which inhibited adipogenesis and promoted lipolysis. Also, FTY720 significantly decreased lipid accumulation in maturing preadipocytes. FTY720 down-regulated the transcriptional levels of the PPARgamma, C/EBPalpha and adiponectin, which are markers of adipogenic differentiation. FTY720 significantly increased the release of glycerol and the expression of the HSL, ATGL and perilipin, which are regulators of lipolysis. These results show that FTY720 prevented obesity by modulating adipogenesis and lipolysis, and suggest that FTY720 is used for the treatment of obesity.
3T3-L1 Cells ; AMP-Activated Protein Kinases/metabolism ; Adipocytes/*drug effects/physiology ; Adipogenesis/drug effects ; Animals ; Anti-Obesity Agents/*pharmacology/therapeutic use ; Antigens, Differentiation/genetics/metabolism ; Carrier Proteins/genetics/metabolism ; Cell Size ; Diet, High-Fat/adverse effects ; Disease Models, Animal ; Enzyme Activation ; Gene Expression Regulation, Enzymologic/drug effects ; Glycogen Synthase Kinase 3/genetics/metabolism ; Lipase/genetics/metabolism ; Lipolysis/drug effects ; Male ; Mice ; Mice, Inbred C57BL ; Obesity/etiology/metabolism/*prevention & control ; Phosphoproteins/genetics/metabolism ; Phosphorylation ; Propylene Glycols/*pharmacology/therapeutic use ; Protein Processing, Post-Translational ; Proto-Oncogene Proteins c-akt/metabolism ; Sphingosine/*analogs & derivatives/pharmacology/therapeutic use ; Sterol Esterase/metabolism

OBJECTIVETo investigate the therapeutic effects of Ping-tang Recipe (, PTR) on high-fat diet (HFD)-induced insulin resistance and non-alcoholic fatty liver disease (NAFLD), and to elucidate the underlying mechanisms.

METHODSForty male SD rats were included in the study. Ten rats were fed on normal diet as normal control, and thirty rats were fed on HFD for 8 weeks to induce obesity, followed with low dose (0.42 g/kg) or high dose (0.84 g/kg) of PTR or vehicle for 8 weeks with 10 animals for each group. Glucose metabolism and insulin sensitivity were evaluated by oral glucose tolerance test and insulin tolerance test. Hepatic steatosis was measured by immunohistochemistry. Liver lipid metabolic genes were analyzed by quantitative real-time polymerase chain reaction, while AMP-activated protein kinase (AMPK) expression was examined by Western blot.

RESULTSRats fed on HFD developed abdominal obesity, insulin resistance and NAFLD. PTR treatment reduced visceral fat (peri-epididymal and peri-renal) accumulation, improved glucose metabolism, and attenuated hepatic steatosis. The expressions of the key lipolytic regulating genes, including peroxisome proliferators-activated receptor γ co-activator 1α (PGC-1α), peroxisome proliferator-activated receptor γ (PRAR-γ) and α (PRAR-α), were up-regulated (P<0.05 or P<0.01), while the expressions of lipogenic genes such as sterol regulatory element-binding protein 1c (SREBP-1c), fatty acid synthase (FAS) and liver fatty acid-binding protein (L-FABP) were down-regulated (P<0.05 or P<0.01). In addition, PTR activated AMPK and promoted acetyl-CoA carboxylase phosphorylation in the liver.

CONCLUSIONSPTR improves insulin resistance and reverse hepatic steatosis in the rat model of HFD-induced obesity through promotion of lipolysis and reduction of lipogenesis, which involves the AMPK signaling pathway, thus representing a new therapeutic intervention for obesity related insulin resistance and NAFLD.

AMP-Activated Protein Kinases ; metabolism ; Animals ; Body Weight ; drug effects ; Diet, High-Fat ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Fatty Liver ; blood ; complications ; prevention & control ; Gene Expression Regulation ; drug effects ; Glucose ; metabolism ; Glucose Tolerance Test ; Insulin Resistance ; Intra-Abdominal Fat ; drug effects ; pathology ; Lipogenesis ; drug effects ; Lipolysis ; drug effects ; Liver ; drug effects ; enzymology ; pathology ; Male ; Obesity ; blood ; complications ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Triglycerides ; metabolism