The Ebf (O/E) family of helix-loop-helix transcription factors plays a significant role in B lymphocyte and neuronal development. The three primary members of this family, Ebf1, 2, and 3, are all expressed in adipocytes, and Ebf1 promotes adipogenesis when overexpressed in NIH 3T3 fibroblasts. Here we report that these three proteins have adipogenic potential in multiple cellular models and that peroxisome proliferatoractivated receptor ␥ (PPAR␥) is required for this effect, at least in part due to direct activation of the PPAR␥1 promoter by Ebf1. Ebf1 also directly binds to and activates the C/EBP␣ promoter, which exerts positive feedback on C/EBP␦ expression. Despite this, C/EBP␣ is dispensable for the adipogenic action of Ebf proteins. Ebf1 itself is induced by C/EBP␤ and ␦, which bind and activate its promoter. Reduction of Ebf1 and Ebf2 proteins by specific short hairpin RNA blocks differentiation of 3T3-L1 cells, suggesting a critical role for these factors and the absence of functional redundancy between members of this family. Altogether, these data place Ebf1 within the known transcriptional cascade of adipogenesis and suggest critical roles for Ebf1 and Ebf2.The last decade has seen an enormous surge of interest in the biology of adipocytes, including the developmental processes by which these cells are formed. This has been fuelled by the convergence of a worldwide epidemic of obesity and diabetes (26, 37), with the recent realization that adipose tissue is an active secretory organ regulating a wide array of physiological processes.Adipogenesis represents a complex series of transcriptional events through which multipotent mesenchymal precursor cells become committed to the adipocyte lineage and ultimately express all of the genes typical of mature fat cells (31). These transcriptional events integrate a variety of extracellular signals that direct fat cell formation in time and space. Most of our knowledge concerning the transcriptional events mediating adipogenesis has come from cultured cell lines such as 3T3-L1 and 3T3-F442A (16, 17) that can be differentiated into fat cells by empirically determined hormonal cocktails. These in vitro systems appear to recapitulate most of the developmental events that take place in vivo and offer the advantage of synchronous differentiation and ease of manipulation. Studies of these cells, as well as cultured mouse embryonic fibroblasts (MEFs) derived from mice with various targeted gene ablations (and more recently, studies from intact animals) have revealed a transcriptional cascade in which the nuclear hormone receptor peroxisome proliferator-activated receptor ␥ (PPAR␥) plays a critical role. In cultured adipocytes and fat pads in vivo, PPAR␥ is both necessary and sufficient for adipogenesis (4, 33, 41). Other transcription factors have also been shown to play an important role in adipogenesis, including the CCAAT/enhancer binding proteins C/EBP␣, C/EBP␤, and C/EBP␦ and the basic helix-loop-helix protein SREBP1c (34). In 3T3-L1 cells exposed to a proadipog...

Zfp521 is a novel antiadipogenic transcription factor that helps to determine the identity of a mesenchymal cell as bone or fat.

Objective Nonalcoholic fatty liver disease (NAFLD) is becoming a leading cause of advanced chronic liver disease. The progression of NAFLD, including nonalcoholic steatohepatitis (NASH), has a strong genetic component, and the most robust contributor is the patatin-like phospholipase domain-containing 3 ( PNPLA3 ) rs738409 encoding the 148M protein sequence variant. We hypothesized that suppressing the expression of the PNPLA3 148M mutant protein would exert a beneficial effect on the entire spectrum of NAFLD. Methods We examined the effects of liver-targeted GalNAc 3 -conjugated antisense oligonucleotide (ASO)-mediated silencing of Pnpla3 in a knock-in mouse model in which we introduced the human PNPLA3 I148M mutation. Results ASO-mediated silencing of Pnpla3 reduced liver steatosis ( p = 0.038) in homozygous Pnpla3 148M/M knock-in mutant mice but not in wild-type littermates fed a steatogenic high-sucrose diet. In mice fed a NASH-inducing diet, ASO-mediated silencing of Pnpla3 reduced liver steatosis score and NAFLD activity score independent of the Pnpla3 genotype, while reductions in liver inflammation score ( p = 0.018) and fibrosis stage ( p = 0.031) were observed only in the Pnpla3 knock-in 148M/M mutant mice. These responses were accompanied by reduced liver levels of Mcp1 ( p = 0.026) and Timp2 ( p = 0.007) specifically in the mutant knock-in mice. This may reduce levels of chemokine attracting inflammatory cells and increase the collagenolytic activity during tissue regeneration. Conclusion This study provides the first evidence that a Pnpla3 ASO therapy can improve all features of NAFLD, including liver fibrosis, and suppress the expression of a strong innate genetic risk factor, Pnpla3 148M, which may open up a precision medicine approach in NASH.