Caveolin‐1 (Cav‐1) expression is increased in hepatic stellate cells (HSC) upon liver cirrhosis and it functions as an integral membrane protein of lipid rafts and caveolae that regulates and integrates multiple signals as a platform. This study aimed to evaluate the role of Cav‐1 in HSC. Thus, the effects of exogenous expression of Cav‐1 in GRX cells, a model of activated HSC, were determined. Here, we demonstrated through evaluating well‐known HSC activation markers – such as α‐smooth muscle actin, collagen I, and glial fibrillary acidic protein – that up regulation of Cav‐1 induced GRX to a more activated phenotype. GRXEGFP‐Cav1 presented an increased migration, an altered adhesion pattern, a reorganization f‐actin cytoskeleton, an arrested cell cycle, a modified cellular ultrastructure, and a raised endocytic flux. Based on this, GRX EGFP‐Cav1 represents a new cellular model that can be an important tool for understanding of events related to HSC activation. Furthermore, our results reinforce the role of Cav‐1 as a molecular marker of HSC activation.

The phytoalexin Resveratrol (3,5,4′-trihydroxystilbene; RSV) has been related to numerous beneficial effects on health by its cytoprotection and chemoprevention activities. Liver fibrosis is characterized by the extracellular matrix accumulation after hepatic injury and can lead to cirrhosis. Hepatic stellate cells (HSC) play a crucial role during fibrogenesis and liver wound healing by changing their quiescent phenotype to an activated phenotype for protecting healthy areas from damaged areas. Strategies on promoting the activated HSC death, the quiescence return or the cellular activation stimuli decrease play an important role on reducing liver fibrosis. Here, we evaluated the RSV effects on some markers of activation in GRX, an HSC model. We further evaluated the RSV influence in the ability of GRX on releasing inflammatory mediators. RSV at 1 and 10 µM did not alter the protein content of α-SMA, collagen I and GFAP; but 50 µM increased the content of these activation-related proteins. Also, RSV did not change the myofibroblast-like morphology of GRX. Interestingly, RSV at 10 and 50 µM decreased the GRX migration and collagen-I gel contraction. Finally, we showed that RSV triggered the increase in the TNF-α and IL-10 content in culture media of GRX while the opposite occurred for the IL-6 content. Altogether, these results suggested that RSV did not decrease the activation state of GRX and oppositely, triggered a pro-activation effect at the 50 µM concentration. However, despite the increase of TNF-α in culture media, these results on IL-6 and IL-10 secretion were in accordance with the anti-inflammatory role of RSV in our model.

Caveolin‐1 (Cav‐1) is an integral membrane protein present in all organelles, responsible for regulating and integrating multiple signals as a platform. Mitochondria are extremely adaptable to external cues in chronic liver diseases, and expression of Cav‐1 may affect mitochondrial flexibility in hepatic stellate cells (HSCs) activation. We previously demonstrated that exogenous expression of Cav‐1 was sufficient to increase some classical markers of activation in HSCs. Here, we aimed to evaluate the influence of exogenous expression and knockdown of Cav‐1 on regulating the mitochondrial plasticity, metabolism, endoplasmic reticulum (ER)‐mitochondria distance, and lysosomal activity in HSCs. To characterize the mitochondrial, lysosomal morphology, and ER‐mitochondria distance, we perform transmission electron microscope analysis. We accessed mitochondria and lysosomal networks and functions through a confocal microscope and flow cytometry. The expression of mitochondrial machinery fusion/fission genes was examined by real‐time polymerase chain reaction. Total and mitochondrial cholesterol content was measured using Amplex Red. To define energy metabolism, we used the Oroboros system in the cells. We report that GRX cells with exogenous expression or knockdown of Cav‐1 changed mitochondrial morphometric parameters, OXPHOS metabolism, ER‐mitochondria distance, lysosomal activity, and may change the activation state of HSC. This study highlights that Cav‐1 may modulate mitochondrial function and structural reorganization in HSC activation, being a potential candidate marker for chronic liver diseases and a molecular target for therapeutic intervention.