Tissue- and breed-specific expression of the chicken fat mass- and obesity-associated gene (FTO)

Fat mass- and obesity-associated (FTO) gene promoted myoblast differentiation through the focal adhesion pathway in chicken

The action of FTO on myoblasts proliferation and differentiation and molecular mechanism underlying it were investigated by transfecting with FTO lentiviral overexpression vector and gene expression profile sequencing. Compared with the control group, myoblasts with FTO transfection was significantly enhanced proliferation; the expression of MYOG and MYOD mRNA was significantly increased. In cells transfected with FTO, 129 differentially expressed genes were determined compared with control group, with 104 up-regulated and 25 down-regulated genes. Twelve pathways (Phagosome, Focal adhesion, Adrenergic signaling in cardiomyocytes, Endocytosis, Cardiac muscle contraction, Toll-like receptor, Ribosome, Tight junction, Regulation of actin cytoskeleton, Cytokine-cytokine receptor interaction, Adrenergic signaling in cardiomyocytes and MAPK) were significantly enriched. Eight genes known to be directly or indirectly related to skeletal muscle development (LAMA5, SPP1, CAV3, RASGRF1, FAK, PDGFB, PDGFRα, and RAC2) were enriched in the focal adhesion and expressed differentially. Altogether, these data suggested that FTO stimulated differentiation of myoblasts through regulation of eight genes enriched in the focal adhesion.

Mouse Maternal High-Fat Intake Dynamically Programmed mRNA m⁶A Modifications in Adipose and Skeletal Muscle Tissues in Offspring

Epigenetic mechanisms have an important role in the pre- and peri-conceptional programming by maternal nutrition. Yet, whether or not RNA m⁶A methylation—an old epigenetic marker receiving increased attention recently—is involved remains an unknown question. In this study, mouse high-fat feeding prior to conception was shown to induce overweight and glucose intolerant dams, which then continued to be exposed to a high-fat diet during gestation and lactation. The dams on a standard diet throughout the whole experiment were used as a control. Results showed that maternal high-fat intake impaired postnatal growth in male offspring, indicated by decreased body weight and Lee’s index at 3, 8 and 15 weeks old, but the percentages of visceral fat and tibialis anterior relative to the whole body weights were significantly increased at eight weeks of age. The maternal high-fat exposure significantly increased mRNA N⁶-methyladenosine (m⁶A) levels in visceral fat at three weeks old, combined with downregulated Fat mass and obesity-associated gene (FTO) and upregulated Methyltransferase like 3 (METTL3) transcription, and these changes were reversed at eight weeks of age. In the tibialis anterior muscle, the maternal high-fat diet significantly enhanced m⁶A modifications at three weeks, and lowered m⁶A levels at 15 weeks of age. Accordingly, FTO transcription was significantly inhibited at three weeks and stimulated at 15 weeks of age, and METTL3 transcripts were significantly improved at three weeks. Interestingly, both FTO and METTL3 transcription was significantly elevated at eight weeks of age, and yet the m⁶A modifications remained unchanged. Our study showed that maternal high-fat intake could affect mRNA m⁶A modifications and its related genes in offspring in a tissue-specific and development-dependent way, and provided an interesting indication of the working of the m⁶A system during the transmission from maternal nutrition to subsequent generations.