Biology subjects

Panzade, G.

Publications and source records attributed to Panzade, G..

4 recordsLinked to original sources

bioRxiv2025

Drosophila midgut tumor-induced insulin resistance systemically remodels lymph gland hematopoiesis during cancer cachexia

Cancer cachexia involves systemic metabolic deregulation along with classical features of muscle wasting, lipolysis, and chronic inflammation. While tumor non-autonomous effects on peripheral organs are recognized, how the tumor rewires the circulating immune cells and hematopoiesis remains unclear. We utilized a Drosophila larval cancer cachexia model by expressing yki3SA in the adult midgut precursors (AMP), which gives rise to a tumor in the larval midgut and recapitulates key cachectic phenotypes, including insulin resistance. Tumor-induced cachexia results in perturbed blood cell homeostasis with a reduced niche and aberrant blood cell differentiation in the larval hematopoietic organ, the lymph gland (LG). Bulk RNA-seq analysis of circulating hemocytes from tumor-bearing larvae revealed upregulation of multiple cachectic ligands, notably ImpL2, an insulin antagonist. We demonstrate that elevated ImpL2 levels reduce LG niche size and promote aberrant blood cell differentiation. Elevated ImpL2 levels and systemic insulin resistance in the tumor-induced cachexia conditions result in abrogation of insulin signaling in the niche-progenitor micro-environment in the LG. DE-cadherin levels in the primary LG lobe are perturbed, and Wingless signaling is down-regulated, driving prohemocyte differentiation. A genetic mimic of systemic ImpL2 overexpression or high sugar diet (HSD) conditions recapitulates these LG phenotypes due to abrogation of the Insulin-Wingless signaling axis. Hemocyte-specific ImpL2 depletion in HSD-fed larvae rescued these defects, suggesting a regulatory role for circulating hemocyte-derived ImpL2. Our findings reveal that hemocyte-derived factors actively contribute to systemic insulin resistance, causing hematopoietic remodeling in cancer cachexia.

cancer biology↗

bioRxiv2025

3' Nucleotide Asymmetry Directs miRNA Strand Selection

Accurate microRNA (miRNA) strand selection is essential for defining the regulatory landscape of the miRNA-induced silencing complex (miRISC). While 5' nucleotide identity and duplex thermodynamics have been proposed to bias strand choice, these features cannot fully explain in vivo strand preferences. Here, we uncover a conserved and previously unrecognized role for 3' nucleotide asymmetry in directing miRNA strand selection in Caenorhabditis elegans and human cells. A favorable 3' terminal nucleotide on the passenger strand promotes selective loading of the opposing guide strand into miRISC, revealing a cooperative interplay between 5' and 3' terminal asymmetries that ensures precise strand discrimination. These findings establish a unified, evolutionarily conserved mechanism for miRNA duplex sorting and expand the fundamental rules governing small RNA biogenesis.

molecular biology↗

bioRxiv2025

LIN-67 functionally interacts with heterochronic miRNAs and regulates developmental timing in Caenorhabditis elegans

Temporal regulation of gene expression is required for developmental transitions, including differentiation, proliferation, and morphogenesis. In the nematode Caenorhabditis elegans, heterochronic microRNAs (miRNAs) regulate the temporal expression of genes that promote animal development. The heterochronic miRNAs lin-4 and let-7 are required during different stages of larval development and are associated with the miRNA-specific Argonaute ALG-1. In this study, we have identified lin-67 as a heterochronic gene that negatively regulates lin-4, let-7, and alg-1. Loss of lin-67 function restores proper developmental timing and stage-specific gene expression to hypomorphic lin-4 and let-7 mutants. We found that loss of lin-67 resulted in a reduced number of seam cells, defects in alae formation, precocious expression of an adult-specific gene reporter, and sterility. LIN-67 contains a K homology (KH) RNA-binding domain and is a homolog of the Sam68-like splicing factor KHDRBS2. We show that LIN-67 localizes to the nucleus throughout animal development and is enriched in nuclear foci. Mutating the KH domain of LIN-67 abolished the nuclear localization of LIN-67, suggesting that the localization of LIN-67 is likely dependent on RNA-binding activity. We show that LIN-67 negatively regulates lin-4 miRNA levels and restores normal levels of let-7 to alg-1 mutants, which can, at least in part, explain how lin-67 suppresses alg-1. Our data indicate that lin-67 is a novel heterochronic gene that regulates developmental timing and miRNA-dependent gene regulation in C. elegans.

developmental biology↗

bioRxiv2022

hnRNPA1/2 homolog hrpa-1 coordinates with miRNAs to regulate gene expression during C. elegans development.

microRNAs (miRNAs) are small non-coding RNAs that play crucial roles in development and in disease. miRNAs associate with Argonaute proteins to form miRNA Induced Silencing Complexes (miRISCs), which post-transcriptionally repress gene expression. miRNA-mediated gene repression itself is subject to regulation by factors that can affect miRNA biogenesis or function. We previously identified HRPA-1, an hnRNPA/B homolog, as a putative physical interactor of miRNAs. Here, we report characterizations of both physical and genetic interactions between HRPA-1 and miRISC components. We confirmed HRPA-1 precipitation in let-7 and miR-58 pulldowns and detected an interaction between HRPA-1 and Argonaute. Deletion of hrpa-1 in a mir-48 mir-241(nDf51) background enhanced the mir-48 mir-241 developmental defects, suggesting that hrpa-1 may be important for let-7 family miRNA activity. Similarly, loss of hrpa-1 strongly enhanced developmental defects associated with two other miRNA mutants, lsy-6(ot150) and let-7(n2853). Depletion of HRPA-1 modestly disrupted miRNA levels and affected global gene expression profiles. We identified a potential target of hrpa-1, R06C1.4, whose knockdown partially recapitulates the hrpa-1(-) effects on miRNA mutant phenotypes. Overall, we demonstrate hrpa-1 and R06C1.4 roles in C. elegans developmental timing regulation and propose models describing possible coordinating modes of gene regulation by HRPA-1 and miRNAs.

molecular biology↗