RESUMEN
Exposure of pregnant F0 mouse dams to the obesogen tributyltin (TBT) predisposes unexposed male descendants to obesity and diverts mesenchymal stem cells (MSCs) toward the adipocytic lineage. TBT promotes adipogenic commitment and differentiation of MSCs in vitro. To identify TBT-induced factors predisposing MSCs toward the adipocytic fate, we exposed mouse MSCs to TBT, the peroxisome proliferator activated receptor gamma (PPARγ)-selective agonist rosiglitazone, or the retinoid X receptor (RXR)-selective agonist LG-100268. Then we determined their transcriptomal profiles to determine candidate microRNAs (miR) regulating adipogenic commitment and differentiation. Of the top 10 candidate microRNAs predicted by Ingenuity Pathway Analysis, miR-21, miR-33, and miR-223 were expressed consistent with an ability to differentially regulate target genes during adipogenesis. We found that 24-hour exposure to 50nM TBT caused miR-223 levels in MSCs to increase; expression of its target genes ZEB1, NFIB, and FOXP1 was decreased. Rosiglitazone and TBT increased miR-223 levels. This induction was inhibited by the PPARγ antagonist T0070907 but not by the RXR antagonists HX531 or UVI3003, placing miR-223 downstream of PPARγ. Chromatin immunoprecipitation confirmed TBT-induced binding of PPARγ to regulatory elements in the miR-223 promoter. miR-223 levels were elevated in white adipose tissue of F2 and F3 male descendants of pregnant F0 mouse dams exposed to 50nM TBT throughout gestation. miR-223 levels were potentiated in males fed an increased fat diet. We infer that TBT induced miR-223 expression and increased adipogenesis in MSCs through the PPARγ pathway and that transgenerationally increased expression of miR-223 plays an important role in the development of obesity caused by TBT exposure.
Asunto(s)
Células Madre Mesenquimatosas , MicroARNs , Femenino , Embarazo , Masculino , Animales , Ratones , Adipogénesis/genética , Rosiglitazona/farmacología , PPAR gamma/metabolismo , Diferenciación Celular/genética , Obesidad/genética , Obesidad/metabolismo , MicroARNs/genética , MicroARNs/metabolismoRESUMEN
Cannabidiol (CBD) is a non-psychoactive phytocannabinoid found in the Cannabis sativa plant. Human exposure to CBD can be through recreational marijuana use, commercially available CBD-containing products, and medical treatments. Previous studies found that cannabidiol may activate the master regulator of adipogenesis, peroxisome proliferator activated receptor gamma (PPARγ). Here we investigated the effects of CBD on adipogenesis in human and mouse multipotent mesenchymal stromal stem cells (MSCs). We tested the effects of CBD on nuclear receptor activation and adipogenic potential to demonstrate the mechanism of CBD effects and employed the in vitro MSC differentiation models to assess adipogenic effects of CBD.Using transient transfection assays, we demonstrated that CBD activated mouse and human PPARγ, but not its heterodimeric partner, the retinoid 'X' receptor, RXR. Our results showed that CBD increased lipid accumulation and the expression of adipogenic genes in mouse and human MSCs in vitro. Adipogenic differentiation induced by CBD was significantly decreased by the PPARγ antagonist T0070907, supporting the hypothesis that CBD promoted differentiation via PPARγ. Taken together, our results indicate that in humans and in mice, CBD induced adipogenic differentiation in MSCs through a PPARγ-dependent mechanism.
Asunto(s)
Adipogénesis/efectos de los fármacos , Cannabidiol/farmacología , Lipogénesis/efectos de los fármacos , Lipólisis/efectos de los fármacos , Células Madre Mesenquimatosas/efectos de los fármacos , PPAR gamma/agonistas , Adipogénesis/fisiología , Animales , Benzamidas/farmacología , Línea Celular Transformada , Humanos , Lipogénesis/fisiología , Lipólisis/fisiología , Células Madre Mesenquimatosas/metabolismo , Ratones , PPAR gamma/antagonistas & inhibidores , PPAR gamma/metabolismo , Piridinas/farmacologíaRESUMEN
Obesity and metabolic disorders have become a worldwide pandemic affecting millions of people. Although obesity is a multifaceted disease, there is growing evidence supporting the obesogen hypothesis, which proposes that exposure to a subset of endocrine disrupting chemicals (EDCs), known as obesogens, promotes obesity. While these effects can be observed in vitro using cell models, in vivo and human epidemiological studies have strengthened this hypothesis. Evidence from animal models showed that the effects of obesogen exposure can be inherited transgenerationally through at least the F4 generation. Transgenerational effects of EDC exposure predispose future generations to undesirable phenotypic traits and diseases, including obesity and related metabolic disorders. The exact mechanisms through which phenotypic traits are passed from an exposed organism to their offspring, without altering the primary DNA sequence, remain largely unknown. Recent research has provided strong evidence suggesting that a variety of epigenetic mechanisms may underlie transgenerational inheritance. These include differential DNA methylation, histone methylation, histone retention, the expression and/or deposition of non-coding RNAs and large-scale alterations in chromatin structure and organization. This review highlights the most recent advances in the field of epigenetics with respect to the transgenerational effects of environmental obesogens. We highlight throughout the paper the strengths and weaknesses of the evidence for proposed mechanisms underlying transgenerational inheritance and why none of these is sufficient to fully explain the phenomenon. We propose that changes in higher order chromatin organization and structure may be a plausible explanation for how some disease predispositions are heritable through multiple generations, including those that were not exposed. A solid understanding of these possible mechanisms is essential to fully understanding how environmental exposures can lead to inherited susceptibility to diseases such as obesity.