Anusha, P. V. | bioRxiv Science

bioRxiv2026

Hepatic Stellate Cell Exosomes Resolve Fibrosis in Mice Livers via Enriched Metabolic and Regenerative Signaling Molecules

BackgroundHepatic stellate cells (HSC) are Vitamin A storing non-parenchymal cells of the liver. During injury and inflammation, HSCs are the major contributors of excessive extracellular matrix (ECM) leading to Liver Fibrosis (LF). Emerging evidence suggests a fibrosis-independent role of these cells as key regulators of liver homeostasis and liver regeneration, emphasising on the dual role of HSCs in liver. HSCs are known to secrete several growth factors through which they largely execute their functions. However, the role of secretome (exosomes) from early activated or undifferentiated HSCs in a fibrotic milieu nor its composition are completely understood. MethodsLX-2 cells were cultured in low to no serum conditions and their isolated exosomes were transplanted into fibrotic severe combined immune deficient (SCID) mice livers, followed by post-transplantation analysis of the liver tissue and compared to the untreated controls. Total proteomic profiling of cell and exosomal cargo was performed using mass spectrometry and the data analysed and compared with the total HSC cell proteome. ResultsSignificant reduction in collagen in the transplanted mice livers compared to untreated fibrotic controls was observed with both the cells and exosomes transplantation. Comparative analysis revealed distinct enrichment of proteins and signaling pathways associated with extracellular matrix regulation, cellular communication, and metabolism in exosomes. Notably, these pathways are prominently represented in the exosomal fraction, suggesting a selective packaging of functional mediators. ConclusionThis study suggests the potential role of HSCs in regulating the complex liver homeostasis via exosomal network of proteins that contribute significantly to liver repair by ECM remodelling and growth factor-mediated signalling to regulate metabolism, fibrosis and liver regeneration. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=126 SRC="FIGDIR/small/721862v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@99bbf4org.highwire.dtl.DTLVardef@1029dd0org.highwire.dtl.DTLVardef@c6f578org.highwire.dtl.DTLVardef@1dba81_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2026

Aging compromises Zebrafish caudal fin regeneration by disrupting Regenerative gene networks and Cellular metabolism

Zebrafish are widely recognized as a powerful vertebrate model for studying epimorphic regeneration due to their remarkable ability to restore complex tissues. However, regenerative efficiency declines with age, potentially due to alterations in gene regulatory networks and cellular metabolism. In the present study, we investigated the molecular and bioenergetic basis of age-associated regenerative decline by comparing young adult (<1 year) and old adult (>3 years) zebrafish during caudal fin regeneration. To further examine the contribution of mitochondrial function, mitochondrial dysfunction was experimentally induced using rotenone (20 nM), a mitochondrial Complex I inhibitor. Regenerative progression was assessed morphologically at 12hpa, 1dpa, 2dpa, 3dpa, and 7dpa, revealing a pronounced delay in fin regrowth in aged and rotenone-treated fish compared with young controls. Behavioral analysis indicated subtle but non-significant changes across experimental groups. Gene expression analysis using quantitative real-time PCR revealed age- and mitochondria-associated dysregulation of key regenerative gene families involved in developmental patterning, extracellular matrix organization, cellular signaling, and mitochondrial metabolism. Proteomic profiling further identified differential expression of proteins associated with mitochondrial bioenergetics, extracellular matrix remodeling, and signaling pathways required for blastema formation and tissue outgrowth. Ultrastructural examination by transmission electron microscopy revealed pronounced mitochondrial abnormalities, including enlarged mitochondria with fragmented or disrupted cristae, in aged and rotenone-treated regenerating tissues. Collectively, our integrative analysis establishes a mechanistic link between aging, mitochondrial dysfunction, and compromised regenerative capacity in zebrafish. The findings provide broader insights into metabolic constraints underlying age-related decline in regenerative potential in vertebrates.

developmental biology↗