RESUMEN
An association between impaired fetal growth and the postnatal development of obesity has been established. Here, by comparing adipocytes differentiated from mesenchymal stem cells (MSCs) taken from the umbilical cord and derived from normal and growth-restricted neonates, we identified the transcription factor SOX6 as highly expressed only in growth-restricted individuals. We found that SOX6 regulates adipogenesis in vertebrate species by activating adipogenic regulators including PPARγ, C/EBPα and MEST. We further show that SOX6 interacts with ß-catenin in adipocytes, suggesting an inhibition of WNT/ß-catenin signaling, thereby promoting adipogenesis. The upstream regulatory region of the MEST gene in MSCs from growth-restricted subjects harbors hypomethylated CpGs next to SOX6 binding motifs, and we found that SOX6 binding is impaired by adjacent CpG methylation. In summary, we report that SOX6 is a novel regulator of adipogenesis synergizing with epigenetic mechanisms.
Asunto(s)
Adipogénesis , Obesidad/genética , Factores de Transcripción SOXD/metabolismo , Células 3T3 , Adipocitos/efectos de los fármacos , Adipocitos/metabolismo , Adipogénesis/efectos de los fármacos , Adipogénesis/genética , Animales , Sitios de Unión , Diferenciación Celular , Islas de CpG/genética , Metilación de ADN/genética , Regulación hacia Abajo/efectos de los fármacos , Humanos , Recién Nacido , Recién Nacido Pequeño para la Edad Gestacional/metabolismo , Larva/efectos de los fármacos , Metabolismo de los Lípidos/genética , Células Madre Mesenquimatosas/citología , Células Madre Mesenquimatosas/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Modelos Biológicos , Oligonucleótidos Antisentido/farmacología , Unión Proteica/efectos de los fármacos , Proteínas/genética , Triglicéridos/metabolismo , Vía de Señalización Wnt/efectos de los fármacos , Vía de Señalización Wnt/genética , Pez CebraRESUMEN
Liver disease is linked to a decreased capacity of hepatocytes to divide. In addition, cellular metabolism is important for tissue homeostasis and regeneration. Since metabolic changes are a hallmark of liver disease, we investigated the connections between metabolism and cell division. We determined global metabolic changes at different stages of liver regeneration using a combination of integrated transcriptomic and metabolomic analyses with advanced functional redox in vivo imaging. Our data indicate that blocking hepatocyte division during regeneration leads to mitochondrial dysfunction and downregulation of oxidative pathways. This resulted in an increased redox ratio and hyperactivity of alanine transaminase allowing the production of alanine and α-ketoglutarate from pyruvate when mitochondrial functions are impaired. Our data suggests that during liver regeneration, cell division leads to hepatic metabolic remodeling. Moreover, we demonstrate that hepatocytes are equipped with a flexible metabolic machinery able to adapt dynamically to changes during tissue regeneration.
Asunto(s)
Hepatocitos/metabolismo , Regeneración Hepática/fisiología , Hígado/metabolismo , Mitocondrias/metabolismo , Animales , Metabolómica/métodos , Ácido Pirúvico/metabolismoRESUMEN
Individuals who are born small for gestational age (SGA) have a risk to develop various metabolic diseases during their life course. The biological memory of the prenatal state of growth restricted individuals may be reflected in epigenetic alterations in stem cell populations. Mesenchymal stem cells (MSCs) from the Wharton's jelly of umbilical cord tissue are multipotent, and we generated primary umbilical cord MSC isolates from SGA and normal neonates, which were subsequently differentiated into adipocytes. We established chromatin state maps for histone marks H3K27 acetylation and H3K27 trimethylation and tested whether enrichment of these marks was associated with gene expression changes. After validating gene expression levels for 10 significant chromatin immunoprecipitation sequencing candidate genes, we selected acyl-coenzyme A synthetase 1 (ACSL1) for further investigations due to its key roles in lipid metabolism. The ACSL1 gene was found to be highly associated with histone acetylation in adipocytes differentiated from MSCs with SGA background. In SGA-derived adipocytes, the ACSL1 expression level was also found to be associated with increased lipid loading as well as higher insulin sensitivity. ACSL1 depletion led to changes in expression of candidate genes such as proinflammatory chemokines and down-regulated both, the amount of cellular lipids and glucose uptake. Increased ACSL1, as well as modulated downstream candidate gene expression, may reflect the obese state, as detected in mice fed a high-fat diet. In summary, we believe that ACSL1 is a programmable mediator of insulin sensitivity and cellular lipid content and adipocytes differentiated from Wharton's jelly MSCs recapitulate important physiological characteristics of SGA individuals.