Sterol regulatory element-binding proteins (SREBPs) are master transcription factors that play a crucial role in regulating genes involved in the biogenesis of cholesterol, fatty acids, and triglycerides. As such, they are implicated in several serious liver diseases, including non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), fibrosis, and hepatocellular carcinoma (HCC). SREBPs are subject to regulation by multiple cofactors and critical signaling pathways, making them an important target for therapeutic interventions. In this review, we first introduce the structure and activation of SREBPs, before focusing on their function in liver disease. We examine the mechanisms by which SREBPs regulate lipogenesis, explore how alterations in these processes are associated with liver disease, and evaluate potential therapeutic strategies using small molecules, natural products, or herb extracts that target these pathways. Through this analysis, we provide new insights into the versatility and multitargets of SREBPs as factors in the modulation of different physiological stages of liver disease, highlighting their potential targets for therapeutic treatment.

Sterol regulatory element-binding proteins (SREBPs) are transcription factors that regulate genes involved in the biogenesis of cholesterol, fatty acids, and triglycerides. SREBPs are involved in the pathogenesis of non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), fibrosis, and hepatocellular carcinoma (HCC). We review the mechanisms by which SREBPs regulate lipogenesis, the alterations in these processes associated with liver diseases, and therapeutic strategies to target these pathways.

Hepatocellular carcinoma (HCC) is a severe disease associated with a poor prognosis. The role of aberrant lipid metabolism in the development and progression of HCC necessitates detailed characterization. Sterol regulatory element‑binding proteins (SREBPs), pivotal transcription factors governing lipogenesis, are central to this process. The present study aimed to assess the regulation of HCC by the SREBP signaling pathway, examining the expression levels of genes in this pathway, the clinical implications and its prognostic value using the Kaplan‑Meier method. Pearson's correlation coefficient was used to identify the co‑expression of SREBP pathway genes in HCC. Genomic analysis examined the frequency of TP53 mutations in groups with and without SREBP pathway alterations. In addition, small interfering RNAs targeting genes of the SREBP pathway were transfected into Huh‑7 and HCC‑LM3 cell lines. Subsequently, Cell Counting Kit‑8 and Transwell assays were carried out to evaluate the viability and invasion of these cells. Reverse transcription‑quantitative PCR and western blotting were performed to investigate the expression of TP53 in response to silencing of SREBP pathway genes. Dysregulation of SREBP pathway genes was detected in HCC tissues compared with in normal liver tissues, and predicted a poor prognosis. Silencing these genes reduced the viability and invasion of HCC cells. Furthermore, abnormal SREBP pathway gene expression was associated with poor survival rates, vascular invasion, advanced tumor stage and an increased incidence of TP53 mutations. By contrast, knockdown of SREBP pathway genes decreased mutant TP53 expression at both the mRNA and protein levels in HCC cells. The findings of the present study suggested that SREBP pathway genes could serve as promising prognostic biomarkers for HCC. The combined analysis of individual gene expression levels offers offer novel insights into the pathogenesis and progression of HCC.

Metabolic dysfunction-associated steatohepatitis (MASH), an advanced stage of metabolic dysfunction-associated steatotic liver disease, is characterized by significant hepatic fibrosis and inflammation. The pan-peroxisome proliferator-activated receptor (pan-PPAR) agonist IVA337 (lanifibranor) has shown potential as an anti-MASH therapeutic, although its mechanisms of action remain incompletely understood. This study explores the effects and mechanisms of IVA337 using two distinct MASH models: two-dimensional (2D) primary human hepatic stellate cells (HSCs) stimulated with transforming growth factor β1 (TGF-β1), and three-dimensional (3D) liver spheroids comprising primary hepatocytes, HSCs, and non-parenchymal cells. In TGF-β1-stimulated HSCs, IVA337 effectively suppressed the expression of fibrosis-related genes, including PAI1, COL1A1, and ACAT2, as well as the inflammatory gene IL6. 3D mouse and human liver spheroid models of MASH, characterized by elevated fibrotic gene expression, were established. IVA337 treatment not only attenuated fibrotic gene expression but also restored lipid content in the MASH spheroids, as evidenced by BODIPY staining. Immunostaining further confirmed a reduction in α-smooth muscle actin and collagen 1 levels after IVA337 treatment. Bulk RNA sequencing and Gene Ontology analysis revealed several lipid metabolism-related genes as key effectors downstream of IVA337. In addition, IVA337 modulated multiple signaling pathways, including IL-17, tumor necrosis factor, NF-κB, phosphatidylinositol 3 kinase/protein kinase B, and mitogen-activated protein kinase. Collectively, these findings show that IVA337 effectively mitigates fibrosis development in both 2D and 3D MASH models by restoring lipid homeostasis and regulating crucial fibrotic and inflammatory pathways.

Metabolic dysfunction and alcohol-associated liver disease (MetALD) results in the development of liver steatosis, inflammation, fibrosis, and hepatocellular carcinoma (HCC). De novo lipogenesis and cholesterol synthesis play an important role in the pathogenesis of MetALD. DHCR7 (7-dehydrocholesterol reductase) regulates the last stages of cholesterol production. We investigated whether targeting DHCR7 can ameliorate the development of MetALD and HCC using experimental models and 3D human liver spheroids. Here, we demonstrate that partial genetic ablation of the Dhcr7 gene and pharmacological blockade of DHCR7 activity with the AY9944 inhibitor suppresses hepatic steatosis (↓ lipid area, n = 15; p <0.001), inflammation (↓ F4/80, n = 6; p <0.01), fibrosis (↓ Sirius red, n = 6; p <0.01), and HCC (↓ AFP/YAP, n = 6; p <0.01) in diethylnitrosamine (DEN)-challenged high-fat diet (HFD) + ethanol (EtOH)-fed mice treated with AY9944 compared with control mice. To translate our findings, the effect of DHCR7 was tested using 3D human liver spheroids, which mimicked MetALD and MetALD-HCC. MetALD liver spheroids were composed of primary human hepatocytes, non-parenchymal cells, and hepatic stellate cells. In contrast, in MetALD-HCC spheroids, the HCC cell line HepG2 was used instead of hepatocytes. Therapeutic administration of AY9944 inhibited inflammation (↓ TNF, p <0.05) and fibrosis in MetALD spheroids (↓ ACTA2, p <0.001; COL1A1, p <0.05; TIMP1, p <0.01; SERPINE1, p <0.05). In turn, dsiRNA-based knockdown of DHCR7 reduced HepG2 proliferation (↓ PCNA, p <0.05; CCNE, p <0.05) and expression of MetALD-HCC markers (↓ AFP, p <0.05; GPC3, p <0.05; YAP, p <0.01). Our data demonstrate that targeting DHCR7 can become a strategy for the treatment of MetALD and HCC. This study demonstrates the critical role of de novo lipogenesis and cholesterol synthesis in the pathogenesis of metabolic dysfunction and alcohol-associated liver disease (MetALD) and its progression to hepatocellular carcinoma (HCC). Our findings identified that the upregulation of DHCR7 contributes to the pathogenesis of MetALD and its inhibition suppresses hepatic steatosis, inflammation, fibrosis, and tumor proliferation. These findings are significant for researchers and clinicians, as they establish that genetic and pharmacological inhibition of DHCR7 is effective in both experimental models and translational 3D human liver spheroids. The results uncover the translational potential of DHCR7-targeted therapies for MetALD and HCC, offering practical implications for the development of novel treatment strategies. Further studies are necessary to optimize these approaches and address potential methodological limitations.