Targeting Adenosine Receptor by Polydeoxyribonucleotide: An Effective Therapeutic Strategy to Induce White-to-Brown Adipose Differentiation and to Curb Obesity

Obesity is a worldwide chronic metabolic disease characterized by an abnormal fat accumulation and represents one of the main risk factors for several diseases. White adipose tissue is the primary site for energy storage in the form of triglycerides, whereas brown adipose tissue does not store energy-providing lipids but rather dissipates it by producing heat. White-to-brown adipocyte trans-differentiation could represent a new target of anti-obesity strategies and result in fat reduction. Previous studies indicated that adenosine receptor activation induces trans-differentiation of white adipocytes to brown adipocytes. The aim of this study was to evaluate the effects of polydeoxyribonucleotide (PDRN), an A2Ar receptor agonist, in an in vitro model of browning. Mouse 3T3-L1 pre-adipocytes were differentiated in mature adipocytes with specific culture media and then treated with PDRN (10 µg/mL), PDRN + ZM241385 (1 µM), CGS21680 (1 µM) and CGS + ZM241385 for 24 h. Cell viability was studied by MTT assay, and browning induction was evaluated by Oil Red O staining and by RT-qPCR to study gene expression of browning markers. PDRN, as well as CGS21680, reduced the accumulation of lipids, cell volume and lipid droplet size; increased the expression of UCP1, PRDM16 and DIO2, considered as browning markers; and reduced the expression of FASn and FABP4, considered as whitening markers. In addition, PDRN decreased leptin expression and enhanced adiponectin mRNA levels. All these effects were abrogated when PDRN was co-incubated with the A2Ar antagonist ZM241385. In conclusion, these results suggest that PDRN is able to induce the white-to-brown adipose differentiation through A2Ar stimulation. Since PDRN is a safe drug already available in the market for other therapeutic indications, its “anti-obesity” potential warrants investigation in a clinical scenario.

Extract of Acalypha australis L. inhibits lipid accumulation and ameliorates HFD-induced obesity in mice through regulating adipose differentiation by decreasing PPARγ and CEBP/α expression

Background: Obesity is a principal risk factor for the development of type 2 diabetes and cardiovascular diseases. Natural plants and/or foods play an important role in the management of obesity. Acalypha australis L. (AAL) is a kind of potherb popular among Asian populations, and it is also consumed as a food ingredient and traditional herbal medicine. Objective: We investigated the effects of water extract from AAL on high-fat-diet (HFD)-induced obese mice and 3T3-L1 adipocytes to develop a new functional food material. Design: Nine-week-old male mice were randomly divided into control (chow diet, n = 6) and HFD (n = 30) group. From 12-weeks onward, mice in the HFD group were further separated into model (saline, 6 mL/ kg), simvastatin (0.11 mg/mL, 6 mL/kg), and AAL treatment (low, middle, and high dosage: 300, 600, and 900 mg/kg) group, with 6 animals per group, while mice in the control group were treated with saline (6 mL/ kg). Food intake, body/fat weight, liver/kidney indexes, and lipid profiles were determined. Tissues were fixed with formalin for pathological examination. Western blotting and PCR were performed to evaluate the protein and mRNA expression in 3T3-L1 adipocytes. Oil Red O staining was used to determine lipid accumulation. Results: AAL administration significantly suppressed body weight gain, and reduced fat pad weight and Lee’s index in obese mice, but had no effect on liver/kidney index. AAL also reduced serum cholesterol, triglyceride, and LDL-C and increased HDL-C levels. Histological analysis revealed that AAL significantly ameliorated lipid accumulation in the liver and subcutaneous adipose tissue. In vitro, Oil Red O staining showed that AAL inhibited adipose differentiation by down-regulating the gene and protein expression of PPARγ and C/EBPα. AAL also reversed HFD-induced intestinal dysbacteriosis. Conclusion: AAL water-soluble extract has a significant anti-adipogenic effect in the HFD-induced obese mice model.

C-type Natriuretic Peptide Promotes Adipogenic Differentiation of Goat Adipose Derived Stem Cells via cGMP/PKG/ p38 MAPK Signal Pathway

BackgroundTwo types of adipose tissue, white adipose and brown adipose, have been identified in mammals. For goat, adipose tissue also plays an important role in improving meat and milk quality. C-type natriuretic peptide (CNP) is a member of natriuretic peptide family. Once CNP binds to natriuretic peptide receptor B (NPR-B), NPR-B induces the production of cGMP, thereby activating PKG and downstream targets. The expression of CNP and NPR-B in adipose tissue led to a hypothesis that CNP could have roles involving in regulation of adipogenesis in goat. However, there are few studies on the relationship between CNP and adipogenesis in goat. In the present study, goat adipose derived stem cells (ADSCs) were isolated and employed to investigate the effect of CNP on adipogenesis in goat.ResultsDuring adipogenic differentiation in goat ADSCs, the expression of NPR-B increased at 4 d and 8 d and reduced at 12 d after differentiation. When goat ADSCs were treated with 100 nM and 1000 nM CNP during adipogenic differentiation, there are more accumulation of lipid droplets in the cytoplasm and the up-regulation in the expression of adipogenesis relative genes including PPAR-γ, FASN and LPL. Interestingly, the expression level of brown adipose genes UCP-1 and PGC-1α were also up-regulated. Furthermore, the cGMP level was increased after treatment with CNP. Adding cGMP analogues 8-pCPT-cGMP (PKG activator) could increase adipogenesis efficiency, and adding both PKG inhibitor Rp-8-CPT-cGMP and CNP inhibited adipogenic differentiation. After treatment with CNP or PKG activator, the phosphorylation of p38 MAPK, MK2 and ATF2 were up-regulated, and their phosphorylation were significantly inhibited when CNP and PKG inhibitor were added simultaneously. SB203580 is the specific inhibitor for p38 MAPK. After treatment with CNP and SB203580 simultaneously, the adipogenic differentiation efficiency of goat ADSCs was significantly inhibited, and the expression of UCP-1 and PGC-1α were also reduced. ConclusionsCNP could promote adipogenic differentiation of goat ADSCs. The stimulative effect of CNP on adipose differentiation depends on the cGMP/PKG/ p38 MAPK signal pathway. Our study will be helpful to understand the regulation mechanism of goat adipose differentiation, especially brown adipose differentiation.

A Fatal Case of Pediatric Primary Myxoid Liposarcoma of the Orbit: A Rare Tumor in an Unusual Location Presenting with Widespread Metastasis

Introduction/Objective A liposarcoma is a tumor derived from primitive mesenchymal cells undergoing adipose differentiation. Liposarcomas are uncommon in childhood, representing only about 2% of childhood sarcomas. Among liposarcomas, is a very rare subtype, the so-called ‘pleomorphic myxoid liposarcoma’ which has extensive myxoid changes and scattered pleomorphic cells. Here we report an autopsy case of an extensively metastatic pleomorphic myxoid liposarcoma. Methods A 12 year-old, African-American boy presented in the ED with ascites and shortness of breath, who later expired despite resuscitation. Autopsy finding showed a primary lesion in the left superior orbital fissure with diffuse metastasis to liver, replacing most of the liver parenchyma (liver weigh 8500 g). Metastatic foci are also present in gallbladder, pancreas, large intestine, bilateral lungs, and inner and outer surfaces of cranium. Histologically, tumor at all sites shows similar morphology, revealing scattered pleomorphic lipoblasts and a myxoid background with arborizing vasculature. Lipoblasts show indented and distorted nuclei and cytoplasmic vacuoles. Immunohistochemically the tumor cells are immunoreactive for p16 (diffusely and strongly) (Figure, D) and S100 (weakly) and negative for AE1/AE3, myogenin, synaptophysin, GFAP, EMA, and CD34. FISH was negative for MDM2 and t(12;16)(q13;p11.2) FUS-DDIT3 rearrangement, ruling out conventional myxoid liposarcoma. Conclusion This case shows the aggressive nature of a poorly studied entity in an uncommon age group and emphasize the need to study childhood liposarcomas in more detail.

Molecular Mechanism of Stem Cell Differentiation into Adipocytes and Adipocyte Differentiation of Malignant Tumor

Adipogenesis is the process through which preadipocytes differentiate into adipocytes. During this process, the preadipocytes cease to proliferate, begin to accumulate lipid droplets, and develop morphologic and biochemical characteristics of mature adipocytes. Mesenchymal stem cells (MSCs) are a type of adult stem cells known for their high plasticity and capacity to generate mesodermal and nonmesodermal tissues. Many mature cell types can be generated from MSCs, including adipocyte, osteocyte, and chondrocyte. The differentiation of stem cells into multiple mature phenotypes is at the basis for tissue regeneration and repair. Cancer stem cells (CSCs) play a very important role in tumor development and have the potential to differentiate into multiple cell lineages. Accumulating evidence has shown that cancer cells can be induced to differentiate into various benign cells, such as adipocytes, fibrocytes, osteoblast, by a variety of small molecular compounds, which may provide new strategies for cancer treatment. Recent studies have reported that tumor cells undergoing epithelial-to-mesenchymal transition can be induced to differentiate into adipocytes. In this review, molecular mechanisms, signal pathways, and the roles of various biological processes in adipose differentiation are summarized. Understanding the molecular mechanism of adipogenesis and adipose differentiation of cancer cells may contribute to cancer treatments that involve inducing differentiation into benign cells.

A New Selective PPARγ Modulator Inhibits Triglycerides Accumulation during Murine Adipocytes’ and Human Adipose-Derived Mesenchymal Stem Cells Differentiation

Understanding the molecular basis of adipogenesis is vital to identify new therapeutic targets to improve anti-obesity drugs. The adipogenic process could be a new target in the management of this disease. Our aim was to evaluate the effect of GMG-43AC, a selective peroxisome proliferator-activated receptor γ (PPARγ) modulator, during adipose differentiation of murine pre-adipocytes and human Adipose Derived Stem Cells (hADSCs). We differentiated 3T3-L1 cells and primary hADSCs in the presence of various doses of GMG-43AC and evaluated the differentiation efficiency measuring lipid accumulation, the expression of specific differentiation markers and the quantification of accumulated triglycerides. The treatment with GMG-43AC is not toxic as shown by cell viability assessments after the treatments. Our findings demonstrate the inhibition of lipid accumulation and the significant decrease in the expression of adipocyte-specific genes, such as PPARγ, FABP-4, and leptin. This effect was long lasting, as the removal of GMG-43AC from culture medium did not allow the restoration of adipogenic process. The above actions were confirmed in hADSCs exposed to adipogenic stimuli. Together, these results indicate that GMG-43AC efficiently inhibits adipocytes differentiation in murine and human cells, suggesting its possible function in the reversal of adipogenesis and modulation of lipolysis.

The relation between serum adipose differentiation-related protein and non-alcoholic fatty liver disease in type 2 diabetes mellitus

Background: Adipose differentiation-related protein (ADRP) is an adipokine. In vitro and animal studies have verified the role of ADRP in lipid metabolism and non-alcoholic fatty liver disease (NAFLD). The aim of this study was to evaluate the interaction between levels of ADRP and NAFLD in type 2 diabetes mellitus (T2DM). Methods: Cross-sectional design. A total of 142 patients with T2DM were assigned to NAFLD (Group-I) and non-NAFLD (Group-II). Anthropometric data were collected. Serum ADRP levels and biochemical parameters were also determined. t test or χ2 test was conducted to compare the data between two groups. Receiver operating characteristic (ROC) curve analysis and logistic regression models were used to assess the interaction between ADRP levels and NAFLD in T2DM. Pearson correlation analysis and linear regression model were used to assess the correlations between serum ADRP levels and other parameters. Results: The serum ADRP level was higher in Group-I than in Group-II. Further, binary logistic regression models demonstrated that ADRP was an independent risk factor related to NAFLD in patients with T2DM. Moreover, as the ADRP level elevated across its tertiles, the percentage of NAFLD in T2DM increased. Multivariate logistic regression models demonstrated that the odds ratio of NAFLD was 8.831 in the highest tertile of ADRP, after adjustment for potential confounders. Area under THE ROC curve of ADRP for predicting the presence of NAFLD in T2DM was 0.738. Finally, multiple stepwise regression analysis indicated that age, waist circumference (WC), homeostasis model assessment of insulin resistance index (HOMA-IR) and triglyceride (TG) were independent factors associated with ADRP levels. Conclusion: High serum ADRP level may be used as an independent risk factor for NAFLD in T2DM. The expression of ADRP may be affected by age, WC, HOMA-IR and TG.

CCL2 affects fat metabolism in liver regeneration by regulating ADRP expression

This study aimed to elucidate the effect of chemokine (c-c motif) ligand 2 (CCL2) on fat metabolism in liver regeneration. CCL2 shRNA expression plasmids were constructed and transfected into rats using hydraulic transgenic technology. Transfection efficiency was measured using a fluorescence microscope. We also measured serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) to test liver functioning. The weights of regenerative livers were recorded and the liver index was calculated. We used immunohistochemistry to determine the expression of PCNA, and used western blot to measure expression levels of adipose differentiation related protein (ADRP). After transfection of pGenesil-1.0-ccl2 into the liver, expression levels of green fluorescent protein were 35% at 6 h, and the liver index as well as levels of ALT, AST, PCNA, and ADRP were all lower than those in the group that underwent partial hepatectomy. We conclude that CCL2 may affect fat metabolism in liver regeneration by inhibiting the expression of ADRP.

Significant Role of Dicer and miR-223 in Adipose Tissue of Polycystic Ovary Syndrome Patients

Polycystic ovary syndrome (PCOS) is a chronic metabolic disease that is associated with obesity and adipose tissue dysfunction. This study aimed to explore the roles of Dicer (an enzyme that processes primary microRNAs) and microRNAs in PCOS. Protein levels were detected by western blotting, and mRNA and microRNA levels were detected by RT-PCR. Dicer-deficient pre-adipocytes were established by lentiviral transfection, and an miR-223 mimic and miR-223 inhibitor were used to overexpress and inhibit miR-223, respectively. 3T3-L1 cells were induced to differentiate into mature adipocytes by IBMX, insulin, and dexamethasone. The degree of differentiation was determined by oil red O staining. An insulin resistance model was established by exposing mature adipocytes to excessive glucose and insulin. The protein levels of Dicer and Ago2 in adipose tissues of PCOS patients were significantly lower than those in control females. A Dicer-deficient 3T3-L1 cell model was successfully established, whose proliferation was inhibited significantly. Insulin-resistant mature adipocytes expressed significantly less Dicer protein than control cells. The differentiation of Dicer-deficient 3T3-L1 cells and their expression of miR-223 and marker genes associated with adipose differentiation were reduced significantly. Furthermore, 3T3-L1 cells showed a weaker ability to develop into mature adipocytes when miR-223 expression was inhibited. An miR-223 mimic was used to recover the differentiation block induced by Dicer deficiency. This rescued the expression of genes associated with adipose differentiation, although the differentiation block was not efficiently rescued. It is concluded that insulin resistance may contribute to the decreased levels of Dicer protein in adipose tissue of PCOS patients. This suggests that dysfunction of Dicer plays a significant role in obesity of PCOS patients. miR-223 is a key factor in Dicer-regulated adipose differentiation, and other microRNAs may be involved in the process.