Biology subjects

Roshan, S.

Publications and source records attributed to Roshan, S..

4 recordsLinked to original sources

bioRxiv2025

Liver Zonation Disruption Fuels Hepatocellular Carcinoma in Chronic Liver Disease

Hepatocellular carcinoma (HCC) arises almost exclusively in chronic liver disease (CLD), yet the classical etiological drivers of injury insufficiently explain why only a subset of patients progress to cancer. Here, we identify disruption of liver metabolic zonation, specifically, aberrant expansion of {beta}-catenin activity from pericentral to periportal territories as a previously unrecognized tumorigenic risk state that emerges across etiologically diverse CLDs. Using spatial transcriptomics and immunohistochemistry from murine liver disease followed by human sample validation, we demonstrate that MASLD/MASH, alcohol-associated hepatitis, viral hepatitis, and immune-mediated cholangiopathies share a striking periportal induction of pericentral {beta}-catenin target programs, indicating a conserved zonation disturbance independent of disease etiology. Since {beta}-catenin expansion occurs alongside inflammation, fibrosis, and metabolic dysfunction in human CLD, its direct oncogenic contribution remained unclear. To functionally isolate the tumorigenic consequence of zonation disruption itself from these confounding disease processes, we employed hepatocyte-specific deletion of ZNRF3 and RNF43--negative regulators that physiologically restrict {beta}-catenin to the pericentral zone. Lineage tracing demonstrates that ZNRF3/RNF43 deletion drives selective periportal hepatocyte proliferation, zonal reprogramming, and tumor initiation in a {beta}-catenin-dependent manner, establishing zonation disruption as a direct mechanistic driver of carcinogenesis. The resulting tumors exhibit a distinct metabolic and immunologic phenotype, including heightened mitochondrial respiration, preserved periportal identity, and T-cell competence, and correspond to a molecularly defined subset comprising 5-10% of human HCCs. Together, these findings reveal {beta}-catenin zonation expansion as a conserved and previously unrecognized HCC risk factor that mechanistically links chronic liver injury to malignant transformation. They further establish ZNRF3/RNF43 deletion as a tractable model of zonation-driven hepatocarcinogenesis and identify a distinct human HCC subtype with unique therapeutic vulnerabilities, opening new avenues for mechanism-based risk stratification, early detection and preventive therapeutic strategies in patients with chronic liver disease.

cancer biology↗

bioRxiv2025

Targeting ZNRF3 and RNF43 to Restore Regeneration and Reverse Metabolic Dysfunction-Associated Steatotic Liver Disease

Liver regeneration and hepatocyte metabolic identity are disrupted in metabolic dysfunction-associated steatotic liver disease (MASLD) and its advanced form, metabolic dysfunction-associated steatohepatitis (MASH), yet the mechanisms of restore liver regeneration and reprogram metabolism for disease reversal remains poorly understood. Here, we show that {beta}-Catenin activity progressively declines in hepatocytes during MASH in both humans and mice, coinciding with impaired regeneration and defective lipid clearance. Targeted deletion of the endogenous WNT pathway inhibitors ZNRF3 and RNF43 in hepatocytes after MASH onset reactivates {beta}-Catenin signaling, leading to robust regression of steatosis, inflammation, and fibrosis, and restoring regenerative capacity across multiple fatty liver disease models. Mechanistically, this therapeutic effect is driven by {beta}-Catenin-dependent induction of the alternative bile acid synthesis pathway without disrupting systemic lipid homeostasis. Importantly, both short-and long-term deletion of ZNRF3/RNF43 restores liver function without triggering tumorigenesis or hepatotoxicity, indicating a safe therapeutic window. These findings reveal that physiological activation of WNT/{beta}-catenin signaling via ZNRF3 and RNF43 offers a viable regenerative and metabolic strategy for reversing fatty liver disease.

cell biology↗

bioRxiv2025

Multivalent Lipid MVL5 Micellar Nanoparticles Exhibit Dramatically Increased Loading of Paclitaxel with PEGylation Enhancing Human Cancer Cell Penetration Depth and Cytotoxicity

Cationic liposomes (CLs) with chain-melted fluid membranes are promising nanocarriers of hydrophobic drugs in cancer chemotherapy, including the frequently employed drug paclitaxel (PTX). CL formulations containing univalent N-[2,3-dioleoyloxy-1-propyl]trimethylammonium chloride (DOTAP), like EndoTAG-1TM, have shown limited success in clinical trials and challenges like endosomal entrapment, limited PTX membrane solubility, and difficulty with in vivo tumor targeting remain. Incorporation of 10 mol% cone-shaped poly(ethylene glycol)-lipid (PEG-lipid) to DOTAP-containing CLs transitions a fraction of the particles to micellar nanodiscs. These PTX--loaded PEGylated CLs and nanodiscs show enhanced cellular uptake in vitro and improved tumor penetration and proapoptotic activity compared to bare CLs in an in vivo solid breast cancer tumor model. Formulations incorporating the multivalent cationic lipid MVL5 (+5e) at 50 mol% form nanoparticles (NPs) comprised almost entirely of nanodiscs, and transition at 75 mol% MVL5 to short micellar rods coexisting with spheres, with rods further transitioning to long flexible rods upon PEGylation. Here, we report on the finding that MVL5-based micellar NPs with disc, rod, and spherical morphologies dramatically improve the solubility of PTX in their fluid lipid membranes by nearly three-fold compared to reference CLs modeled on the EndoTAG-1TM formulation. Cell viability assays revealed that this improved PTX solubility for MVL5 micellar NPs leads to improved cytotoxic efficacy, which is further improved by PEGylation. Remarkably, using fluorescent microscopy and image particle analysis, we find that the cellular uptake and penetration depth of MVL5 nanoparticles is significantly improved by PEGylation. The findings are consistent with a model where the rate-limiting step of PTX delivery by cationic lipid NPs is diffusion of endocytic vesicles containing NPs through the actin mesh near the cell surface combined with the hoping rate of PTX from endosomal membrane to nearby microtubules. PEGylated cationic lipid nanoparticles containing MVL5 therefore represent a very promising hydrophobic cancer drug delivery vehicle for nanomedicine applications.

bioengineering↗

bioRxiv2024

Acidic Conditions Promote Clustering of Cancer Cell Derived Extracellular Vesicles and Enhance their Fusion with Synthetic Liposomes

Extracellular vesicles (EVs) are endogenous vesicles secreted by cells. Exosomes, a subset of EVs ranging from 30 to 150 nanometers in diameter, contain cytosolic proteins, gene-silencing miRNA, and gene-encoding mRNA and have roles in intercellular communication. Exosomes show promise as cancer chemotherapeutic drug delivery vehicles given their low immunogenicity and cell-specific delivery of luminal contents to the cytosol of target cells. However, loading exosomes with cancer chemotherapeutic drugs is inefficient, which limits their therapeutic application. To overcome this barrier, methods have been developed which allow fusion of EVs with synthetic liposomes preloaded with therapeutic drug. While these methods show more efficient fusion than passive incubation of EVs with liposomes, they risk either damage to the membrane proteins of the EVs or contamination of the final EV-liposome hybrid with residual depletant molecules, which can cause side effects or hinder content delivery. Here, we present a new, weakly perturbative method which uses acidic conditions (pH 5) to significantly enhance the fusion of EVs and synthetic, neutral liposomes (NLs) compared to passive incubation in pH 7.4 at 37 {degrees}C. An adapted Forster resonance energy transfer (FRET) based lipid mixing assay confirms that fusion is enhanced with this method. This significant finding implies that lipid-only synthetic liposomes are able to fuse with EVs, creating EV-liposome hybrids under relevant temperature and pH conditions, with no other non-lipidic component, such as fusogenic amphipathic peptides, added to the synthetic liposomes. Remarkably, differential interference contrast (DIC) and fluorescence microscopy show that this enhancement of fusion corresponds with the onset of clustering of mixtures of EVs and NLs, or EVs alone, in acidic but not neutral pH conditions. The findings support a hypothesis that content release from EVs in early to late endocytic environment may be a combination of protein-protein clustering interactions and a lipidic component. Further, this study provides a novel method for enhanced fusion of EVs and liposomes which is expected to preserve EV membrane proteins and functionality towards the development of therapeutic hybrid drug delivery vehicles in nanomedicine applications.

biophysics↗