Sagar, S. C. | bioRxiv Science

bioRxiv2026

Brahmi Ghrita Exerts Nephroprotective Effects by Restoring Cytoskeletal Integrity and Ion Transport in Drosophila Model of Polycystic Kidney Disease

BackgroundPolycystic kidney disease (PKD) is a genetic disorder characterized by progressive cyst formation, epithelial disorganization, and impaired fluid transport, ultimately leading to renal failure. Disruption of cytoskeletal dynamics and epithelial polarity is central to PKD pathogenesis. Malpighian tubules (MTs) of Drosophila melanogaster serve as a conserved renal analog, and caspase-3/Drice-deficient flies exhibit a robust PKD-like tubular phenotype, providing a powerful in vivo model to investigate therapeutic interventions. PurposeThis study evaluates the therapeutic potential of the Brahmi Ghrita (BG) in ameliorating PKD-like defects in Drosophila Drice mutants and elucidates the underlying cellular and molecular mechanisms. MethodsDrice mutant flies were reared with dietary BG supplementation, and developmental viability (pupation and eclosion) was assessed. Tubule morphology was analyzed by measuring cyst formation and tubule dimensions. Stellate cell (SC) number, shape, and nuclear size were quantified. Cytoskeletal organization and epithelial polarity were examined using F-actin and polarity markers. Molecular analyses included assessment of Rho1 signaling, Gelsolin, and Rho kinase (Rok) localization. Tubule physiology was evaluated by uric acid crystal deposition and Na{square}/K{square}-ATPase expression. ResultsBG supplementation significantly improved pupation and eclosion rates in Drice mutants and markedly reduced cystic dilation by restoring tubule width without altering developmental length. BG selectively increased stellate cell number and normalized aberrant morphology, while principal cell number remained unchanged. Cytoskeletal disorganization and polarity defects were rescued, accompanied by normalization of elevated Rho1 levels and restoration of the actin-severing protein Gelsolin. BG enhanced Na{square}/K{square}-ATPase expression and reduced uric acid accumulation, consistent with improved epithelial transport function. Additionally, BG promoted nuclear enrichment of Rok, indicating altered Rho-associated signaling dynamics. ConclusionBrahmi Ghrita confers nephroprotective effects in a genetic PKD model by coordinately restoring cytoskeletal integrity, epithelial polarity, and ion transport machinery. Rather than broadly suppressing Rho signaling, BG appears to rebalance the Rho1-Gelsolin axis and re-establish transport competency, culminating in structural and functional rescue. These findings provide mechanistic evidence supporting BG as a multi-target modulator of epithelial homeostasis in PKD-relevant contexts. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=123 SRC="FIGDIR/small/705756v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@1b22d58org.highwire.dtl.DTLVardef@bf1a69org.highwire.dtl.DTLVardef@5f04b4org.highwire.dtl.DTLVardef@2de776_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

bioRxiv2025

Caspase-3/Drice as a critical regulator of actin dynamics through its dual control of small RhoGTPase family and Gelsolin in the Malpighian tubules of Drosophila.

Caspases are executioner enzymes primarily known for their role in driving programmed cell death. However, they are now also known to regulate plethora of non-apoptotic functions such as proliferation, differentiation, endocytic trafficking, cell polarity, morphogenesis, inflammatory response and immune response. Here, in this study we report the role of Drosophila caspase 3, Drice, in spatial and dynamic regulation of actin filaments during development and proper functioning of the Malpighian tubules (MTs) of Drosophila melanogaster. Previously, we showed that Drice is crucial for the morphogenesis of the MTs, and its absence results in erroneous RhoGTPase signaling driving disarray in actin organization, this led to the formation of multiple fluid filled cysts in tubules. In the present study, we show that altered expression of two member of the Rho family of small GTPases, Rho1 and CDC42, perturbs the downstream signaling cascade. Reduced expression of Rok aborts the Rho1 signaling in Drice null mutants, whereas enhanced expression of CDC42 results in Arp2/3-driven hyper-polymerization of actin filaments. We compared Rho-GTPase interacting partners in Oregon R+ (Control) and Drice mutants, and identified the absence of Gelsolin-Rho1 interaction in Drice mutants. Moreover, its expression was significantly downregulated, in the MTs. These factors collectively influence the F-actin to G-actin ratio, which significantly affects actin organization in the MTs. These results demonstrate the crucial role of caspase-3/Drice in maintaining actin homeostasis and tubule morphogenesis. This study highlights the importance of caspase activity beyond apoptosis and its potential function in the developmental and physiological processes. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=158 SRC="FIGDIR/small/679759v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@162c4b2org.highwire.dtl.DTLVardef@15fabdcorg.highwire.dtl.DTLVardef@c0ec3org.highwire.dtl.DTLVardef@19d2f83_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗