The pro-/anti-inflammatory effects of different fatty acids on visceral adipocytes are partially mediated by GPR120.

PURPOSE: This study examines whether G-protein coupled receptor 120 (GPR120) is involved in the pro-/anti-inflammatory effects of different types of fatty acids (FAs) in human visceral adipocytes, and whether these effects may be altered in obesity, a state with a chronic inflammation. METHODS: Pro-/anti-inflammatory effects of palmitic, oleic, linoleic and docosahexaenoic acids on human visceral adipocytes were tested in mature adipocytes from non-obese and morbidly obese (MO) subjects. Also, the effects of these FAs were tested when the GPR120 gene was silenced. RESULTS: In adipocytes from non-obese subjects, palmitic and linoleic acids increased TNF-α and IL-6 mRNA expression (p < 0.05), and decreased IL-10 and adiponectin expression (p < 0.05). However, oleic and docosahexaenoic acids (DHA) produced the opposite effect (p < 0.05). In adipocytes from MO subjects, all FAs used increased TNF-α and IL-6 expression (p < 0.05). Palmitic and linoleic acids decreased IL-10 and adiponectin expression (p < 0.05), but oleic acid and DHA did not have significant effects. Only oleic acid increased adiponectin expression (p < 0.05). The effects of FAs on TNF-α, IL-6, IL-10 and adiponectin expression in non-obese and MO subjects were significantly annulled when the GPR120 gene was silenced in visceral adipocytes differentiated from human mesenchymal stem cells. CONCLUSIONS: FAs are capable of directly acting on visceral adipocytes to modulate differently TNF-α, IL-6, IL-10 and adiponectin expression, with a different and greater effect in MO subjects. These effects are largely annulled when GPR120 expression was silenced, which suggests that they could be mediated by GPR120.

Effects of Two Different Rhodiola rosea Extracts on Primary Human Visceral Adipocytes.

Rhodiola rosea (Rro) has been reported to have various pharmacological properties, including anti-fatigue, anti-stress and anti-inflammatory activity. It is also known to improve glucose and lipid metabolism, but the effects of Rhodiola rosea on adipocyte differentiation and metabolism are not still elucidated. In this study the anti-adipogenic and lipolytic activity of two extracts of Rhodiola rosea, containing 3% salidroside (RS) or 1% salidroside and 3% rosavines (RR) on primary human visceral adipocytes was investigated. Pre-adipocytes were analyzed after 10 and 20 days of treatment during differentiation and after 7 days of treatment when they reached mature shape. The RS extract significantly induced higher apoptosis and lipolysis in comparison to control cells and to RR extract. In contrast, RR extract significantly reduced triglyceride incorporation during maturation. Differentiation of pre-adipocytes in the presence of RS and RR extracts showed a significant decrease in expression of genes involved in adipocyte function such as SLC2A4 and the adipogenic factor FGF2 and significant increase in expression of genes involved in inhibition of adipogenesis, such as GATA3, WNT3A, WNT10B. Furthermore RR extract, in contrast to RS, significantly down-regulates PPARG, the master regulator of adipogenesis and FABP4. These data support the lipolytic and anti-adipogenetic activity of two different commercial extracts of Rhodiola rosea in primary human visceral pre-adipocytes during differentiation.

Human visceral and subcutaneous adipose stem and progenitor cells retain depot-specific adipogenic properties during obesity.

Abdominal obesity associates with cardiometabolic disease and an accumulation of lipids in the visceral adipose depot, whereas lipid accumulation in the subcutaneous depot is more benign. We aimed to further investigate whether the adipogenic properties where cell-intrinsic, or dependent on a depot-specific or obesity-produced microenvironment. We obtained visceral and subcutaneous biopsies from non-obese women (n = 14) or women living with morbid obesity (n = 14) and isolated adipose stem and progenitor cells (ASPCs) from the stromal vascular fraction of non-obese (n = 13) and obese (n = 13). Following in vitro differentiation into mature adipocytes, we observed a contrasting pattern with a lower gene expression of adipogenic markers and a higher gene expression of immunogenic markers in the visceral compared to the subcutaneous adipocytes. We identified the immunogenic factor BST2 as a marker for visceral ASPCs. The effect of obesity and insulin resistance on adipogenic and immunogenic markers in the in vitro differentiated cells was minor. In contrast, differentiation with exogenous Tumor necrosis factor resulted in increased immunogenic signatures, including increased expression of BST2, and decreased adipogenic signatures in cells from both depots. Our data, from 26 women, underscore the intrinsic differences between human visceral and subcutaneous adipose stem and progenitor cells, suggest that dysregulation of adipocytes in obesity mainly occurs at a post-progenitor stage, and highlight an inflammatory microenvironment as a major constraint of human adipogenesis.

Visceral Adipose Tissue of Prediabetic and Diabetic Females Shares a Set of Similarly Upregulated microRNAs Functionally Annotated to Inflammation, Oxidative Stress and Insulin Signaling.

Hypertrophic and hypoxic visceral adipose tissue (VAT) secretes proinflammatory cytokines promoting insulin resistance (IR), prediabetes and type 2 diabetes (T2DM) microRNAs (miRNAs) are markers of metabolic disorders regulating genes critical for e.g., inflammation, glucose metabolism, and antioxidant defense, with raising diagnostic value. The aim of the current study was to evaluate whether hyperglycemia is able to affect the expression of selected miRNAs in VAT of prediabetic (IFG) and diabetic (T2DM) patients vs. normoglycemic (NG) subjects using qPCR. Statistical analyses suggested that miRNAs expression could be sex-dependent. Thus, we determined 15 miRNAs as differentially expressed (DE) among NG, T2DM, IFG females (miR-10a-5p, let-7d-5p, miR-532-5p, miR-127-3p, miR-125b-5p, let-7a-5p, let-7e-5p, miR-199a-3p, miR-365a-3p, miR-99a-5p, miR-100-5p, miR-342-3p, miR-146b-5p, miR-204-5p, miR-409-3p). Majority of significantly changed miRNAs was similarly upregulated in VAT of female T2DM and IFG patients in comparison to NG subjects, positively correlated with FPG and HbA1c, yet, uncorrelated with WHR/BMI. Enrichment analyses indicated involvement of 11 top DE miRNAs in oxidative stress, inflammation and insulin signaling. Those miRNAs expression changes could be possibly associated with low-grade chronic inflammation and oxidative stress in VAT of hyperglycemic subjects.

Intermittent hypoxia, energy expenditure, and visceral adipocyte recovery.

BACKGROUND AND OBJECTIVE: Body weight of patients with obstructive sleep apnea after initiation of nasal continuous positive airway pressure appears to increase. We hypothesized that intermittent hypoxia (IH) will decrease energy expenditure (EE), and that normoxic recovery will lead to body weight gains. METHODS: C57BL/6 J male mice were exposed to either 12 h/day of mild IH (alternating FIO2-10-11% and 21%; 640 s cycle), or severe IH (FIO2-6-7%-21%; 180 s cycle) or sham IH daily for 4 or 8 weeks. After exposures, EE was evaluated while mice were kept under normoxia for 5 weeks and organ histology was evaluated. RESULTS: EE was not decreased by IH. However, visceral white adipocyte size after normoxic recovery was significantly increased in severe IH in an intensity-dependent manner. CONCLUSION: Our hypothesis that IH would decrease EE was not corroborated. However, IH and normoxic recovery seem to promote severity-dependent enlargement of visceral adipocytes, likely reflecting altered energy preservation mechanisms induced by IH.

Original Research: Hydroxytyrosol, an ingredient of olive oil, reduces triglyceride accumulation and promotes lipolysis in human primary visceral adipocytes during differentiation.

Hydroxytyrosol has various pharmacological properties, including anti-oxidative stress and anti-inflammatory activities, preventing hyperglycemia, insulin resistance, and the metabolic syndrome. The present study is focused on the anti-adipogenic and lipolytic activity of hydroxytyrosol on primary human visceral adipocytes. Pre-adipocytes were analyzed after 10 (P10) and 20 (P20) days of treatment during differentiation and after 7 (A7) days of treatment when they reached mature shape. The treatment with hydroxytyrosol extract significantly (P < 0.001) increased apoptosis in P10 and P20 cells in comparison to control and A7 cells; significantly (P < 0.001) reduced triglyceride accumulation in P20 cells compared to P10 and control cells; and significantly (P < 0.001) increased lipolysis in P20 cells in comparison to control cells and A7 mature adipocytes. Hydroxytyrosol-treated P20 cells significantly (P < 0.05) increased expression of genes involved in inhibition of adipogenesis, such as GATA2, GATA3, WNT3A, SFRP5, HES1, and SIRT1. In contrast, genes involved in promoting adipogenesis such as LEP, FGF1, CCND1, and SREBF1 were significantly down-regulated by hydroxytyrosol treatment. These data suggest that hydroxytyrosol promotes lipolysis and apoptotic activity in primary human visceral pre-adipocytes during differentiation and does not affect already mature adipocytes.

Different anti-adipogenic effects of bio-compounds on primary visceral pre-adipocytes and adipocytes.

Several natural compounds exhibit strong capacity for decreasing triglyceride accumulation, enhancing lipolysis and inducing apoptosis. The present study reports the anti-adipogenic effects of Silybum marianum (SL), Citrus aurantium (CA), Taraxacum officinale (TO), resveratrol (RE), Curcuma longa (CU), caffeine (CF), oleuropein (OL) and docosahexaenoic acid (DHA) in reducing differentiation and increasing lipolysis and apoptosis. Analyses were performed on human primary visceral pre-adipocytes after 10 (P10) and 20 (P20) days of treatment during differentiation and on mature adipocytes after 7 days of treatment (A7). The percentage of apoptosis induced by TO extract in P10 and P20 cells was significantly higher than that induced by all other compounds and in CTRL cells. Triglyceride accumulation was significantly lower in cells treated with DHA, CF, RE in comparison to cells treated with OL and in CTRL cells. Treatments with CF, DHA and OL significantly incremented lipolysis in P20 cells in comparison to other compounds and in CTRL cells. On the contrary, the treatment of A7 cells with OL, CA and TO compounds significantly increased cell lipolysis. The addition of CF in differentiating P20 pre-adipocytes significantly increased the expression of genes involved in inhibition of adipogenesis, such as GATA2, GATA3, WNT1, WNT3A, SFRP5, and DLK1. Genes involved in promoting adipogenesis such as CCND1, CEBPB and SREBF1 were significantly down-regulated by the treatment. The screening of bioactive compounds for anti-adipogenic effects showed that in differentiating cells TO extract was the most effective in inducing apoptosis and CF and DHA extracts were more efficient in inhibition of differentiation and in induction of cell lipolysis.

Chemokine profiles of human visceral adipocytes from cryopreserved preadipocytes: Neutrophil activation and induction of nuclear factor-kappa B repressing factor.

AIMS: In obesity, infiltration of adipose tissue by proinflammatory immune cells causes chronic low-grade inflammation. We investigated the chemokine profiles of human visceral adipocytes by the reverse transcription polymerase chain reaction and the effect of human neutrophil elastase (HNE) on monocyte chemoattractant protein-1 (MCP-1) mRNA and protein levels. MAIN METHODS: Human adipocytes were obtained from cryopreserved omental preadipocytes of subjects with a body mass index (BMI) <30kg/m(2) or >30kg/m(2) and were cultured to assess chemokine production. KEY FINDINGS: Chemokine responses associated with obesity-related inflammation were well preserved in cultured human adipocytes derived from cryopreserved preadipocytes. Visceral adipocytes from subjects with a BMI >30kg/m(2) expressed mRNA for MCP-1, regulated on activation, normal T cell expressed and secreted (RANTES), epithelial cell-derived neutrophil-activating peptide-78 (ENA-78), interleukin-8 (IL-8), lymphotactin-ß, and fractalkine. Although visceral adipocytes from subjects with a BMI <30kg/m(2) also expressed MCP-1, RANTES, ENA-78, and IL-8 mRNA, neither lymphotactin-ß nor fraktalkine mRNA was detected. Interestingly, expression of MCP-1 mRNA was decreased significantly after exposure to HNE (85×10(3)µM/L), suggesting the induction of nuclear factor-kappa B repressing factor. SIGNIFICANCE: Adipocytes from subjects with a BMI >30kg/m(2) or <30kg/m(2) have different chemokine profiles. Only adipocytes from subjects with a BMI >30kg/m(2) express lymphotactin-ß and fractalkine mRNA. Differential chemokine profiles of visceral adipocytes contribute to infiltration of adipose tissue by adaptive immune cells. Neutrophil activation is involved in induction of nuclear factor-kappa B repressing factor, resulting in regulation of immune cell trafficking.

Effects of Rosmarinus officinalis extract on human primary omental preadipocytes and adipocytes.

The prevalence of obesity is increasing all over the world. Although it has been shown that natural substances influence fat metabolism, little is known about the effect on cellular and molecular mechanisms in human. In this in vitro study, the activity of Rosmarinus officinalis (RO) standardized extract in modulating human primary visceral preadipocytes differentiation, lipolysis, and apoptosis was investigated. Moreover, gene expression of key adipogenesis modulators and microRNAs-seq were evaluated. Preadipocytes treated with RO extract significantly reduced triglyceride incorporation during maturation in a dose-dependent manner without affecting cell viability. In addition, RO extract stimulated lipolytic activity in differentiating preadipocytes and mature adipocytes in treated cells compared to controls. Differentiating preadipocytes incubated in the presence of RO extract showed a decreased expression of cell cycle genes such as cyclin D1, cyclin-dependent kinase 4, cyclin-dependent kinase inhibitor 1A (p21, Cip1) and an increased expression of GATA binding protein 3, wingless-type MMTV integration site family, member 3A mRNA levels. Recent studies have demonstrated that some phytochemicals alter the expression of specific genes and microRNAs that play a fundamental role in the pathogenesis of obesity and related diseases. Interestingly, genes modulated in RO-treated cells were found to be validated miRNAs targets, such as let-7f-1, miR-17, and miR-143. The results indicated that RO extract modulates human adipocyte differentiation and significantly interferes with adipogenesis and lipid metabolism, supporting its interest as dietary supplement.

Cellular and molecular comparison of redifferentiation of intramuscular- and visceral-adipocyte derived progeny cells.

In the present study, mature adipocytes from pig-derived visceral and intramuscular adipose depots were isolated, purified, and allowed to undergo dedifferentiation and redifferentiation in vitro. During the redifferentiation process at days 1, 2, 4, 6, and 8, we observed that both visceral- and intramuscular adipose-derived progeny cells possessed a similar capacity to accumulate lipid. However, at days 10, 12, 14, and 16, the latter progeny cells accumulated lipid much faster--the content almost doubled at day 16 (P < 0.05). Such faster potential of lipid accumulation in the intramuscular adipose-derived progeny cells was then supported by higher expressions of CCAAT/enhancer binding protein-alpha (CEBP-alpha) and peroxisome proliferator-activated receptor-gamma (PPAR-gamma) at all these nine time points, and diacylglycerol O-acyltransferase homolog 1 (DGAT1), fatty acid binding protein 4 (FABP4) and fatty acid synthase (FASN) at some time points (P < 0.05). These preliminary data suggest that adipose depot differences exist with respect to ability of purified cells of the adipose lineage to redifferentiate and form viable lipid-assimilating cells in vitro. Therefore, our present study might provide a foundation to develop tools for biomedical and agricultural applications, as well as to determine the regulation of depot-specific cells of the adipose lineage. Further studies with more animals will validate and expand our results.