The Gata2 repression during 3T3-L1 preadipocyte differentiation is dependent on a rapid decrease in histone acetylation in response to glucocorticoid receptor activation

GATA3: Orchestrating cellular fate through differentiation and proliferation

Cell proliferation and differentiation are two fundamental biological processes that occur in biological systems, tightly regulated by various factors such as transcription factors (TFs). Zinc finger proteins are TFs responsible for maintaining the biological balance via coordinating development and functionality within the living cells. GATA binding protein 3 (GATA3), one of the zinc finger proteins, plays an essential role in driving differentiation and proliferation-related processes, thereby contributing to the regulation of the dynamism and productivity of living cells. By elucidating the complex interactions governed by GATA3, this underscores its significance in maintaining cellular homeostasis. Thus, the current review delves into the molecular pathways influenced by GATA3, highlighting its involvement in multiple developmental processes of various tissues and body sites, particularly in the hematopoietic system (T-cell differentiation), neural tissue differentiation, adipose tissue, as well as epithelial cell maturation.

Deciphering the Role of the SREBF1 Gene in the Transcriptional Regulation of Porcine Adipogenesis Using CRISPR/Cas9 Editing

Sterol regulatory element-binding protein 1 (SREBP1) is an important transcription factor that controls lipid metabolism and adipogenesis. Two isoforms, SREBP1a and SREBP1c, are generated by alternative splicing of the first exon of the SREBF1 gene. The porcine SREBF1 gene has mainly been studied for its role in lipid metabolism in adipose tissues, but little is known about its involvement, and the role of its two isoforms, in adipogenesis. The aim of the present study was to introduce a deletion in the 5'-regulatory region of the SREBF1c gene, considered crucial for adipogenesis, using the Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9 (CRISPR/Cas9) method. This approach allows for the evaluation of how inhibiting SREBF1c transcription affects the expression of other genes essential for adipocyte differentiation, particularly PPARG, CEBPA, CEBPB, CEBPD, GATA2, and FABP4. It was observed that disrupting the SREBF1c isoform had no effect on the GATA2 gene but did result in a decrease in the expression of the CEBPA and CEBPD genes, an increase in the expression of CEBPB, and an inhibition in the expression of the PPARG and FABP4 genes. These changes in gene expression blocked adipogenesis, as could be seen by the failure of lipid droplets to accumulate. Our results provide evidence highlighting the pivotal role of the SREBP1c isoform in the regulation of porcine adipogenesis.

Novel insights into regulators and functional modulators of adipogenesis

Adipogenesis is a process that differentiates new adipocytes from precursor cells and is tightly regulated by several factors, including many transcription factors and various post-translational modifications. Recently, new roles of adipogenesis have been suggested in various diseases. However, the molecular mechanisms and functional modulation of these adipogenic genes remain poorly understood. This review summarizes the regulatory factors and modulators of adipogenesis and discusses future research directions to identify novel mechanisms regulating adipogenesis and the effects of adipogenic regulators in pathological conditions. The master adipogenic transcriptional factors PPARγ and C/EBPα were identified along with other crucial regulatory factors such as SREBP, Kroxs, STAT5, Wnt, FOXO1, SWI/SNF, KLFs, and PARPs. These transcriptional factors regulate adipogenesis through specific mechanisms, depending on the adipogenic stage. However, further studies related to the in vivo role of newly discovered adipogenic regulators and their function in various diseases are needed to develop new potent therapeutic strategies for metabolic diseases and cancer.

Microscopic image-based classification of adipocyte differentiation by machine learning

Adipocyte differentiation is a sequential process involving increased expression of peroxisome proliferator-activated receptor gamma (PPARγ), adipocyte-specific gene expression, and accumulation of lipid droplets in the cytoplasm. Expression of the transcription factors involved is usually detected using canonical biochemical or biomolecular procedures such as Western blotting or qPCR of pooled cell lysates. While this provides a useful average index for adipogenesis for some populations, the precise stage of adipogenesis cannot be distinguished at the single-cell level, because the heterogenous nature of differentiation among cells limits the utility of averaged data. We have created a classifier to sort cells, and used it to determine the stage of adipocyte differentiation at the single-cell level. We used a machine learning method with microscopic images of cell stained for PPARγ and lipid droplets as input data. Our results show that the classifier can successfully determine the precise stage of differentiation. Stage classification and subsequent model fitting using the sequential reaction model revealed the action of pioglitazone and rosiglitazone to be promotion of transition from the stage of increased PPARγ expression to the next stage. This indicates that these drugs are PPARγ agonists, and that our classifier and model can accurately estimate drug action points and would be suitable for evaluating the stage/state of individual cells during differentiation or disease progression. The incorporation of both biochemical and morphological information derived from immunofluorescence image of cells and so overcomes limitations of current models.

Keratinocyte Growth Factor Stimulates Growth of p75+ Neural Crest Lineage Cells During Middle Ear Cholesteatoma Formation in Mice

During development, cranial neural crest (NC) cells display a striking transition from collective to single-cell migration and undergo a mesenchymal-to-epithelial transformation to form a part of the middle ear epithelial cells (MEECs). While MEECs derived from NC are known to control homeostasis of the epithelium and repair from otitis media, paracrine action of keratinocyte growth factor (KGF) promotes the growth of MEECs and induces middle ear cholesteatoma (cholesteatoma). The animal model of cholesteatoma was previously established by transfecting a human KGF-expression vector. Herein, KGF-inducing cholesteatoma was studied in Wnt1-Cre/Floxed-enhanced green fluorescent protein (EGFP) mice that conditionally express EGFP in the NC lineages. The cytokeratin 14-positive NC lineage expanded into the middle ear and formed cholesteatoma. Moreover, the green fluorescent protein-positive NC lineages comprising the cholesteatoma tissue expressed p75, an NC marker, with high proliferative activity. Similarly, a large number of p75-positive cells were observed in human cholesteatoma tissues. Injections of the immunotoxin murine p75-saporin induced depletion of the p75-positive NC lineages, resulting in the reduction of cholesteatoma in vivo. The p75 knockout in the MEECs had low proliferative activity with or without KGF protein in vitro. Controlling p75 signaling may reduce the proliferation of NC lineages and may represent a new therapeutic target for cholesteatoma.

Mstn knockdown decreases the trans-differentiation from myocytes to adipocytes by reducing Jmjd3 expression via the SMAD2/SMAD3 complex

Myostatin (Mstn) is an important growth/differentiation factor, and knockdown of Mstn reduces fat content. Here, we knocked down Mstn expression in C2C12 myoblasts and then induced adipogenic trans-differentiation in the cells. The effects of Mstn knockdown on lipid droplet contents and H3K27me3 marker expression on adipocyte-specific genes were detected. The results showed that Mstn knockdown reduced the formation of lipid droplets, downregulated the expression of adipocyte-specific genes, and increased H3K27me3 marker expression on adipocyte-specific genes. Chromatin immunoprecipitation analysis showed that the SMAD2/SMAD3 complex could combine with the Jumonji D3 (Jmjd3) promoter and that Mstn regulated Jmjd3 expression through this process. Jmjd3 overexpression removed the H3K27me3 marker and increased the expression of adipocyte-specific genes. Overall, our results showed that Mstn regulated Jmjd3 expression through SMAD2/SMAD3, thus affecting the H3K27me3 marker on adipocyte-specific genes and the trans-differentiation from myocytes to adipocytes.