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The role of the CEBPB gene in porcine adipogenesis: a study using CRISPR/Cas9-edited mesenchymal stem cells
Abstract Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 is a powerful tool for gene editing and the regulation of gene expression. It enables the introduction of targeted mutations, thereby facilitating functional studies of specific genes in various cellular processes. In this study, we aimed to generate a deletion in the promoter region of the CEBPB gene, which encodes a transcription factor involved in adipogenesis, and to evaluate the impact of this modification on the adipogenic differentiation potential of porcine mesenchymal stem cells (MSCs). A 575-bp deletion was introduced in the target region, resulting in the generation of both homozygous and heterozygous mutant cells. Adipogenic differentiation was assessed by quantifying transcript levels of adipocyte marker genes ( GATA2 , CEBPA , PPARG , and FABP4 ) at days 0, 4, 6, 8, and 10 of the differentiation process. Disruption of CEBPB expression led to the downregulation of these adipogenic markers, indicating impaired adipocyte differentiation. Additionally, to assess the proliferative capacity of the edited cells, the expression levels of proliferation-associated genes ( CCND1 , MCM2 , and PCNA ) were measured. A reduction in their transcript levels was observed in both homozygous and heterozygous mutant cells. These findings indicate that both homozygous and heterozygous deletions in the CEBPB promoter completely block adipogenesis and alter MSC proliferation, highlighting the pivotal role of CEBPB not only in adipogenic differentiation but also in the regulation of cell proliferation in porcine mesenchymal stem cells. These results provide new insights into the molecular mechanisms underlying adipose tissue development and have implications for pig breeding strategies aimed at optimizing carcass composition, as well as for biomedical research focused on adipose tissue biology.
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.
Droplet Digital PCR Quantification of Selected Intracellular and Extracellular microRNAs Reveals Changes in Their Expression Pattern during Porcine In Vitro Adipogenesis
Extracellular miRNAs have attracted considerable interest because of their role in intercellular communication, as well as because of their potential use as diagnostic and prognostic biomarkers for many diseases. It has been shown that miRNAs secreted by adipose tissue can contribute to the pathophysiology of obesity. Detailed knowledge of the expression of intracellular and extracellular microRNAs in adipocytes is thus urgently required. The system of in vitro differentiation of mesenchymal stem cells (MSCs) into adipocytes offers a good model for such an analysis. The aim of this study was to quantify eight intracellular and extracellular miRNAs (miR-21a, miR-26b, miR-30a, miR-92a, miR-146a, miR-148a, miR-199, and miR-383a) during porcine in vitro adipogenesis using droplet digital PCR (ddPCR), a highly sensitive method. It was found that only some miRNAs associated with the inflammatory process (miR-21a, miR-92a) were highly expressed in differentiated adipocytes and were also secreted by cells. All miRNAs associated with adipocyte differentiation were highly abundant in both the studied cells and in the cell culture medium. Those miRNAs showed a characteristic expression profile with upregulation during differentiation.