FSP27 and Links to Obesity and Diabetes Mellitus

Comparative effect of high intensity interval training and moderate intensity continuous training on metabolic improvements and regulation of Cidea and Cidec in obese C57BL/6 mice

Obesity is a chronic disease associated with increased risk of cardiovascular disease, diabetes, metabolic dysfunction associated steatotic liver disease and certain cancers. High intensity interval training (HIIT) and moderate intensity continuous training (MICT) are effective in preventing and managing obesity. However, the comparative effects of these modalities on metabolic disorders need to be better mechanistically explored. This study aimed to comprehensively assess the effects of MICT and HIIT on key metabolic organs and underlying mechanisms. C57BL/6 mice were randomized to receive either a chow diet or high fat diet for 12 weeks, followed by random assignment of high-fat-fed mice to no exercise, MICT or HIIT groups for additional 5 weeks. At the end, both HIIT and MICT significantly alleviated high-fat-induced weight gain and lipids disorder and impaired liver function. HIIT was more effective in enhancing insulin sensitivity, ameliorating hepatic steatosis, reducing adipocyte hypertrophy. Additionally, HIIT restored the high-fat-induced downregulation of Cidea, Cidec and Atgl in inguinal white adipose tissue and liver. Furthermore, HIIT resulted in upregulation of interleukin 6 (Il-6) in skeletal muscle. The exogenous addition of Il-6 to primary white adipocytes significantly downregulated Cidec, and up-regulated Atgl expression. In conclusion, HIIT is superior to MICT in improving metabolic dysfunction, likely mediated through Il-6-induced downregulation of Cidea and Cidec, thereby promoting lipolysis.

Attenuation of brown adipocyte whitening in high-fat diet-induced obese rats: Effects of melatonin and β-hydroxybutyrate on Cidea, Fsp27 and MT1 expression

AIM

To investigate the effects of β-hydroxybutyrate (BHB) and melatonin on brown adipose tissue (BAT) plasticity in rats fed a high-fat diet (HFD).

METHODS

We employed a 7-week experimental design for a study on 30 male Sprague-Dawley rats divided into five groups: (1) a control-diet fed group; (2) a high-fat diet (HFD)-fed group; (3) a group that received an HFD and a BHB solution in their drinking water; (4) a group that received an HFD with 10 mg/kg/day melatonin in their drinking water; and (5) a group that received an HFD and were also treated with the combination of BHB and melatonin. Following the treatment period, biochemical indices, gene expression levels of key thermogenic markers (including uncoupling protein 1 [UCP1], PR domain containing 16 [PRDM16], Cidea, fat-specific protein 27 [Fsp27], and metallothionein 1 [MT1]), and stereological assessments of BAT were evaluated.

RESULTS

Treatment with BHB and melatonin significantly boosted blood ketone levels, improved lipid profiles, and reduced weight gain from an HFD. It also downregulated genes linked to WAT, namely, Cidea and Fsp27, and upregulated key BAT markers, including UCP1, PRDM16 and peroxisome proliferator-activated receptor-gamma coactivator-1-alpha. Additionally, the co-treatment increased MT1 receptor expression and enhanced the structural density of BAT.

CONCLUSION

The combined oral administration of BHB and melatonin successfully prevented the whitening of BAT in obese rats fed an HFD, indicating its potential as a therapeutic strategy for obesity-related BAT dysfunction. The synergistic effects of this treatment underscore the potential of a combined approach to address BAT dysfunction in obesity.

Hepatoprotective efficacy and interventional mechanism of the panaxadiol saponin component in high-fat diet-induced NAFLD mice

Dietary administration is a promising strategy for intervention in non-alcoholic fatty liver disease (NAFLD). Our research team has identified a biologically active component, the panaxadiol saponin component (PDS-C) isolated from total saponins of panax ginseng, which has various pharmacological and therapeutic functions. However, the efficacy and mechanism of PDS-C in NAFLD were unclear. This study aimed to elucidate the hepatoprotective effects and underlying action mechanism of PDS-C in NAFLD. Mice were fed a high-fat diet (HFD) for 8 weeks to induce NAFLD and treated with PDS-C and metformin as the positive control for 12 weeks. PDS-C significantly alleviated liver function, hepatic steatosis and blood lipid levels, reduced oxidative stress and inflammation in NAFLD mice. In vitro, PDS-C has been shown to reduce lipotoxicity and ROS levels while enhancing the antioxidant and anti-inflammatory capabilities in HepG2 cells induced by palmitic acid. PDS-C induced AMPK phosphorylation, leading to upregulation of the Nrf2/HO1 pathway expression and downregulation of the NFκB protein level. Furthermore, our observations indicate that PDS-C supplementation improves insulin resistance and glucose homeostasis in NAFLD mice, although its efficacy is not as pronounced as metformin. In conclusion, these results demonstrate the hepatoprotective efficacy of PDS-C in NAFLD and provide potential opportunities for developing functional products containing PDS-C.

A MDM2 inhibitor MX69 inhibits adipocytes adipogenesis and differentiation

Adipose tissue, a key regulator of systemic energy homeostasis, can synthesize and store triglycerides to meet long-term energy demands. In response to nutrient overload, adipose tissue expands by hypertrophy or hyperplasia. As an oncogene, MDM2 has exerted diverse biological activities including human development, tissue regeneration, and inflammation, in addition to major oncogenic activities. Recently, some studies indicated that MDM2 plays an important role in adipose tissue function. However, the role of MX69, a MDM2 inhibitor, in adipose tissue function has not been fully elucidated. Here, we administered MX69 intraperitoneally to high-fat diet-induced obesity (DIO) wild type C57BL/6 mice and found that MX69 could promote the body weight and white adipose tissue weight of DIO mice. Moreover, MX69 had no effects on glucose tolerance and insulin sensitivity in DIO mice. And MX69 treatment decreased the size of adipocytes and fat deposition in adipose tissue and inhibited 3T3-L1 preadipocytes differentiation. Mechanistically, MX69 inhibited the protein levels of MDM2 and the mRNA levels of genes related to adipogenesis and differentiation. In summary, our results indicated that MDM2 has a crucial and complex role in regulating adipose tissue function.

Hypoglycemic and Hypolipidemic Activity of Polygonatum sibiricum Fermented with Lactobacillus brevis YM 1301 in Diabetic C57BL/6 Mice

Polygonatum sibiricum (PS) has been used as herbal medicine to treat type 2 diabetes mellitus (T2DM). However, how lactic acid fermentation of PS influences glucose and lipid metabolism remains unclear. The current study was undertaken to evaluate the hypoglycemic and hypolipidemic effects of PS fermented with Lactobacillus brevis YM 1301 (YM 1301) in streptozotocin and high-fat diet-induced T2DM mice. Biochemical analysis revealed that supplementation with metformin, PS, or fermented Polygonatum sibiricum (FPS) lowered the fasting blood glucose, insulin, total cholesterol, triglyceride, and low-density lipoprotein cholesterol of diabetic mice. FPS showed relatively more potency to reduce the homeostasis model assessment-insulin resistance and glycated hemoglobin than PS. Moreover, a high dosage of FPS protected against glucose intolerance and insulin resistance by increasing the ratio of phosphor-AKT/AKT. Histological examination and quantitative polymerase chain reaction results showed that dietary FPS ameliorated the lipid accumulation in liver and white adipose tissue (WAT) by inhibiting lipogenesis, enhancing lipolysis, and fatty acid oxidation. FPS exhibited greater efficacy than PS on improving the transcriptional expression of adipose triacylglyceride lipase, carnitine palmitoyltransferase 1, and uncoupling protein 1. In addition, FPS exerted a striking anti-inflammatory effect by suppressing the expression of interleukin 6, interleukin 1β, tumor necrosis factor-α, and transforming growth factor-β in WAT of diabetic C57BL/6 mice. Finally, FPS supplementation enhanced the activation of AMPK. In conclusion, these results suggest that the FPS may be more promising than PS as a potential therapeutic agent for diabetes and obesity.

Comparative Transcriptome Analysis of Key Genes and Pathways Activated in Response to Fat Deposition in Two Sheep Breeds With Distinct Tail Phenotype

Fat tail in sheep presents a valuable energy reserve that has historically facilitated adaptation to harsh environments. However, in modern intensive and semi-intensive sheep industry systems, breeds with leaner tails are more desirable. In the present study, RNA sequencing (RNA-Seq) was applied to determine the transcriptome profiles of tail fat tissues in two Chinese sheep breeds, fat-rumped Altay sheep and thin-tailed Xinjiang fine wool (XFW) sheep, with extreme fat tail phenotype difference. Then the differentially expressed genes (DEGs) and their sequence variations were further analyzed. In total, 21,527 genes were detected, among which 3,965 displayed significant expression variations in tail fat tissues of the two sheep breeds (P < 0.05), including 707 upregulated and 3,258 downregulated genes. Gene Ontology (GO) analysis disclosed that 198 DEGs were related to fat metabolism. In Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, the majority of DEGs were significantly enriched in "adipocytokine signaling," "PPAR signaling," and "metabolic pathways" (P < 0.05); moreover, some genes were involved in multiple pathways. Among the 198 DEGs, 22 genes were markedly up- or downregulated in tail fat tissue of Altay sheep, indicating that these genes might be closely related to the fat tail trait of this breed. A total of 41,724 and 42,193 SNPs were detected in the transcriptomic data of tail fat tissues obtained from Altay and XFW sheep, respectively. The distribution of seven SNPs in the coding regions of the 22 candidate genes was further investigated in populations of three sheep breeds with distinct tail phenotypes. In particular, the g.18167532T/C (Oar_v3.1) mutation of the ATP-binding cassette transporter A1 (ABCA1) gene and g.57036072G/T (Oar_v3.1) mutation of the solute carrier family 27 member 2 (SLC27A2) gene showed significantly different distributions and were closely associated with tail phenotype (P < 0.05). The present study provides transcriptomic evidence explaining the differences in fat- and thin-tailed sheep breeds and reveals numerous DEGs and SNPs associated with tail phenotype. Our data provide a valuable theoretical basis for selection of lean-tailed sheep breeds.