Inhibition of PPARγ Gene Particle Downregulates the Differentiation of Rabbit Bone Marrow Mesenchymal Stem Cells into Adipocytes

This study aims to evaluate the effect of peroxisome proliferator-activated receptor (PPAR) γ gene inhibition on the adipogenic differentiation of rabbit bone marrow mesenchymal stem cells (BMSCs). Primary BMSCs were isolated from rabbit bone marrow, cultured, and the markers of BMSCs on cell’s surface were analyzed using flow cytometry. The experiment involved five groups, namely, control: untreated BMSCs; model: BMSCs treated with ethanol; empty siRNA: BMSCs treated with ethanol + empty siRNA; PPARγ: BMSCs treated with ethanol + PPARγ siRNA; and PPARγ inhibitor: BMSCs treated with ethanol + T0070907. RT-PCR and Western blotting were used to detect changes in the expression level of PPARγ, PETALA2 (AP2), lipoprotein lipase (LPL), fatty acid transport protein (FATP) 1, and fatty acid transporter (FAT). Adipocyte count and triacylglycerol content of the model and the empty siRNA groups were considerably greater than the control group ( P < 0.01 ). After the inhibition with PPARγ or T0070907, adipocyte count and triacylglycerol content of the PPARγ and T0070907 groups were significantly reduced ( P < 0.01 ), with no statistically significantly difference than the control group ( P > 0.05 ). The expression levels of PPARγ gene and protein in the model and empty siRNA groups were ominously enhanced than the control group ( P < 0.01 ), and after inhibition with PPARγ or T0070907, the PPARγ gene or protein expression level of PPARγ and T0070907 groups significantly reduced ( P < 0.01 ), with no statistically significance difference compared to the control group ( P > 0.05 ). The expression levels of Ap2, LPL, FATP1, and FAT genes in the model and empty siRNA groups were considerably greater compared to the control group ( P < 0.01 ). Inhibition with PPARγ or T0070907 in the PPARγ and T0070907 groups, respectively, lead to significantly reduced expression levels of adipogenic genes ( P < 0.01 ), with no statistically significance difference compared to the control ( P > 0.05 ). Inhibition of PPARγ gene downregulates the differentiation of BMSCs into adipocytes, indicating its putative role in the expression of adipogenic genes.

The antianginal ranolazine does not confer beneficial actions against hepatic steatosis in male mice subjected to high-fat diet and streptozotocin induced type 2 diabetes

Non-alcoholic fatty liver disease (NAFLD) is characterized by the accumulation of excess fat in the liver in the absence of alcohol and increases one’s risk for both diabetes and cardiovascular disease (e.g. angina). We have shown that the second-line anti-anginal therapy, ranolazine, mitigates obesity-induced NAFLD, and our aim was to determine whether these actions of ranolazine also extend to NAFLD associated with type 2 diabetes (T2D). 8-week-old male C57BL/6J mice were fed either a low-fat diet or a high-fat diet for 15-weeks, with a single dose of streptozotocin (STZ; 75 mg/kg) administered in the high-fat diet fed mice at 4-weeks to induce experimental T2D. Mice were treated with either vehicle control or ranolazine during the final 7-weeks (50 mg/kg once daily). We assessed glycemia via monitoring glucose tolerance, insulin tolerance, and pyruvate tolerance, whereas hepatic steatosis was assessed via quantifying triacylglycerol content. We observed that ranolazine did not improve glycemia in mice with experimental T2D, while also having no impact on hepatic triacylglycerol content. Therefore, the salutary actions of ranolazine against NAFLD may be limited to obese individuals but not those who are obese with T2D.

Improving the co-production of triacylglycerol and isoprenoids in Chlamydomonas

Biodiesel and natural products derived from microalgae require a smaller land area and have higher production rates compared to plants and animals and has recently attracted considerable interest. However, biodiesel production from microalgal triacylglycerol is still far from commercial realization due to its high production cost. One way to overcome this obstacle is to improve the triacylglycerol accumulation and couple its production with other high-value compounds. Of particular interest is the sterol biosynthetic pathway with squalene as an intermediate due to its close relationship with triacylglycerol and carotenoid biosynthetic pathways. Besides, both squalene and carotenoids are isoprenoid lipids that have health benefits. Perturbation of one pathway has been suggested to affect other pathways. Three terbinafine-sensitive mutants of the green microalga Chlamydomonas reinhardtii were isolated using terbinafine, a drug that inhibits squalene epoxidase, leading to squalene accumulation. One of the mutants, tfs2, accumulated twice the amount of wild-type triacylglycerol. As well as squalene accumulation, the presence of terbinafine further increased the triacylglycerol content. The level of prenyl lipid carotenoid and chlorophyll was also more significant than that of the wild type. Growth and photosynthesis were not compromised in this mutant. This is the first study that has demonstrated a mutant screening method to improve the co-production of TAG and isoprenoid lipids in a green microalgae.

Growth, health and biochemical composition of the sea cucumber Cucumaria frondosa after multi-year holding in effluent waters of land-based salmon culture

Methods have been proposed to mitigate the environmental footprint of aquaculture, including co-culture of species occupying different trophic levels. In this study, sea cucumbers Cucumaria frondosa, either from production tanks fed with effluent water from land-based salmon culture over 4 yr or collected from the field, were compared using stable isotope, lipid and fatty acid (FA) signatures as indicators of waste assimilation, health and biochemical composition. Enrichment of δ13C in muscle bands and intestine and of δ15N in muscle bands, gonad and intestine was detected in captive individuals relative to wild individuals, suggesting the uptake and assimilation of waste from salmon culture. The higher levels of FA biomarkers typical of salmon feed (18:1ω9, 18:2ω6 and 20:1ω9) and lower ω3/ω6 ratio in the captive sea cucumbers were also in line with assimilation of the waste. However, male and female sea cucumbers from the co-culture became smaller with time, their organ indices were lower than those of wild individuals (e.g. poorly developed gonad), and their biochemical composition differed: triacylglycerol content was greater in wild individuals and phospholipid content was greater in captive individuals. Also, FA profiles of all tissues differed between the 2 groups, whereas total lipid in muscle bands and gonad remained similar. Overall, results support that co-culture with suspension-feeding sea cucumbers may help mitigate the salmon industry footprint. In turn, the biochemical composition of the sea cucumbers changed, and their reduced size and body indices suggest that this food source does not provide suitable nutrients to sustain growth and reproduction.

Enhanced Triacylglycerol Content and Gene Expression for Triacylglycerol Metabolism, Acyl-Ceramide Synthesis, and Corneocyte Lipid Formation in the Epidermis of Borage Oil Fed Guinea Pigs

Triacylglycerol (TAG) metabolism is related to the acyl-ceramide (Cer) synthesis and corneocyte lipid envelope (CLE) formation involved in maintaining the epidermal barrier. Prompted by the recovery of a disrupted epidermal barrier with dietary borage oil (BO: 40.9% linoleic acid (LNA) and 24.0% γ-linolenic acid (GLA)) in essential fatty acid (EFA) deficiency, lipidomic and transcriptome analyses and subsequent quantitative RT-PCR were performed to determine the effects of borage oil (BO) on TAG content and species, and the gene expression related to overall lipid metabolism. Dietary BO for 2 weeks in EFA-deficient guinea pigs increased the total TAG content, including the TAG species esterified LNA, GLA, and their C20 metabolized fatty acids. Moreover, the expression levels of genes in the monoacylglycerol and glycerol-3-phosphate pathways, two major pathways of TAG synthesis, increased, along with those of TAG lipase, acyl-Cer synthesis, and CLE formation. Dietary BO enhanced TAG content, the gene expression of TAG metabolism, acyl-Cer synthesis, and CLE formation.

Placebo-controlled randomised trial with liraglutide on magnetic resonance endpoints in individuals with type 2 diabetes: a pre-specified secondary study on ectopic fat accumulation

Aims/hypothesis The aim of this work was to assess the effect of liraglutide on ectopic fat accumulation in individuals with type 2 diabetes mellitus. Methods This study is a pre-specified subanalysis of the MAGNetic resonance Assessment of VICTOza efficacy in the Regression of cardiovascular dysfunction In type 2 diAbetes mellitus (MAGNA VICTORIA) study, with primary endpoints being the effects of liraglutide on left ventricular diastolic and systolic function. The MAGNA VICTORIA study was a single-centre, parallel-group trial in 50 individuals with type 2 diabetes mellitus (BMI >25 kg/m2) who were randomly assigned (1:1, stratified for sex and insulin use) to receive liraglutide 1.8 mg once daily or placebo for 26 weeks, added to standard care. Participants, study personnel and outcome assessors were blinded to treatment allocation. The secondary endpoints of visceral adipose tissue (VAT), abdominal subcutaneous adipose tissue (SAT) and epicardial fat were measured with MRI. Hepatic triacylglycerol content (HTGC) and myocardial triacylglycerol content (MTGC) were quantified with proton MR spectroscopy. Between-group differences (change from baseline) were tested for significance using ANCOVA. Mean differences with 95% CIs were reported. Results The trial was completed in 2016. Twenty-four participants were randomised to receive liraglutide and 26 to receive placebo. One patient in the liraglutide group withdrew consent before having received the study drug and was not included in the intention-to-treat analysis. Liraglutide (n = 23) vs placebo (n = 26) significantly reduced body weight (liraglutide 98.4 ± 13.8 kg to 94.3 ± 14.9 kg; placebo 94.5 ± 13.1 kg to 93.9 ± 13.2 kg; estimated treatment effect −4.5 [95% CI −6.4, −2.6] kg). HbA1c declined in both groups without a significant treatment effect of liraglutide vs placebo (liraglutide 66.7 ± 11.5 mmol/mol to 55.0 ± 13.2 mmol/mol [8.4 ± 1.1% to 7.3 ± 1.2%]; placebo 64.7 ± 10.2 mmol/mol to 56.9 ± 6.9 mmol/mol [8.2 ± 1.0% to 7.5 ± 0.7%]; estimated treatment effect −2.9 [95% CI −8.1, 2.3] mmol/mol or −0.3 [95% CI −0.8, 0.2]%). VAT did not change significantly between groups (liraglutide 207 ± 87 cm2 to 203 ± 88 cm2; placebo 204 ± 63 cm2 to 200 ± 55 cm2; estimated treatment effect −7 [95% CI −24, 10] cm2), while SAT was reduced by a significantly greater extent with liraglutide than with placebo (liraglutide 361 ± 142 cm2 to 339 ± 131 cm2; placebo 329 ± 107 cm2 to 333 ± 125 cm2; estimated treatment effect −29 [95% CI −51, −8] cm2). Epicardial fat did not change significantly between groups (liraglutide 8.9 ± 4.3 cm2 to 9.1 ± 4.7 cm2; placebo 9.6 ± 4.1 cm2 to 9.6 ± 4.6 cm2; estimated treatment effect 0.2 [95% CI −1.5, 1.8] cm2). Change in HTGC was not different between groups (liraglutide 18.1 ± 11.2% to 12.0 ± 7.7%; placebo 18.4 ± 9.4% to 14.7 ± 10.0%; estimated treatment effect −2.1 [95% CI −5.3, 1.0]%). MTGC was not different after treatment with liraglutide (1.5 ± 0.6% to 1.2 ± 0.6%) vs placebo (1.3 ± 0.5% to 1.2 ± 0.6%), with an estimated treatment effect of −0.1 (95% CI −0.4, 0.2)%. There were no adjudicated serious adverse events. Conclusions/interpretation Compared with placebo, liraglutide-treated participants lost significantly more body weight. Liraglutide primarily reduced subcutaneous fat but not visceral, hepatic, myocardial or epicardial fat. Future larger studies are needed to confirm the results of this secondary endpoint study. Trial registration ClinicalTrials.gov NCT01761318. Funding This study was funded by Novo Nordisk A/S (Bagsvaerd, Denmark).