Biology subjects

Bilder, D.

Publications and source records attributed to Bilder, D..

10 recordsLinked to original sources

bioRxiv2026

A chronic interorgan wound response appropriated by Drosophila tumors to induce intestinal inflammation

Tumors exploit wound healing pathways not only to foster progression but also to lethally disrupt systemic physiology. A prominent example is malignant activation of the clotting cascade, causing pathology through unclear mechanisms that extend beyond thrombosis. Here we show that tumors in a coagulopathy-inducing Drosophila cancer model remotely disrupt intestinal stem cell (ISC) homeostasis. This paraneoplastic, tumor-gut communication axis induces intestinal dysplasia and barrier dysfunction, mimicking remote chronic injury that we show activates inflammation in ISCs via EGFR signaling. Unlike the interorgan responses observed with acute injury, which involves Jak/STAT signaling to activate regenerative ISC proliferation, dysregulated division in both tumor-bearing and chronically injured flies is sustained only by EGFR activation. We also present evidence that deposition of clot material locally onto gut stroma links tumor-driven coagulopathy to intestinal inflammation. Collectively, these findings distinguish mechanisms of remote responses to chronic versus transient stresses. Furthermore, they show how tumor-initiated, dysregulated wound healing programs can drive tissue-specific, pathological inflammation in a host.

cancer biology↗

bioRxiv2025

Fly wounds and tumors restrict macrophages via a matrix degradation-moderating protease inhibitor

Breaches of epithelial homeostasis trigger an inflammatory response. Not only initiation but negative regulation of the response is critical, as autoinflammation can cause tissue damage and chronic disease. Epithelial breaches can be signaled by damage-associated molecular patterns (DAMPs), including basement membrane (BM) degradation, that attract inflammatory cells. Here we show that the conserved thioester-containing protein Tep3 from Drosophila limits innate immune cell attachment to damaged and transformed epithelia. Tep3 is produced in wounds and tumors alongside the matrix metalloprotease MMP1. Tep3 inhibits MMP1 proteolytic activity, reducing production of a BM DAMP that is necessary for macrophage association. A Drosophila tumor upregulates Tep3 to limit an MMP1- and macrophage-dependent anti-tumor immune response, thus accelerating progression and host death. Hence, fly tumors can exploit a physiological anti-inflammatory axis to pathologically limit their immune restriction.

genetics↗

bioRxiv2024

Basement membrane patterning by spatial deployment of a secretion-regulating protease

While paradigms for patterning of cell fates in development are well-established, paradigms for patterning morphogenesis, particularly when organ shape is influenced by the extracellular matrix (ECM), are less so. Morphogenesis of the Drosophila egg chamber (follicle) depends on anterior-posterior distribution of basement membrane (BM) components such as Collagen IV (Col4), whose symmetric gradient creates tissue mechanical properties that specify the degree of elongation. Here we show that the gradient is not regulated by Col4 transcription but instead relies on post-transcriptional mechanisms. The metalloprotease ADAMTS-A, expressed in a gradient inverse to that of Col4, limits Col4 deposition in the follicle center and manipulation of its levels can cause either organ hyper- or hypo-elongation. We present evidence that ADAMTS-A acts within the secretory pathway, rather than extracellularly, to limit Col4 incorporation into the BM. High levels of ADAMTS-A in follicle termini are normally dispensable but suppress Col4 incorporation when transcription is elevated. Our data show how an organ can employ patterned expression of ECM proteases with intracellular as well as extracellular activity to specify BM properties that control shape.

developmental biology↗

bioRxiv2024

Paraneoplastic renal dysfunction in fly cancer models driven by inflammatory activation of stem cells

Tumors can induce systemic disturbances in distant organs, leading to physiological changes that enhance host morbidity. In Drosophila cancer models, tumors have been known for decades to cause hypervolemic bloating of the abdominal cavity. Here we use allograft and transgenic tumors to show that hosts display fluid retention associated with autonomously defective secretory capacity of fly renal tubules, which function analogous to those of the human kidney. Excretion from these organs is blocked by abnormal cells that originate from inappropriate activation of normally quiescent renal stem cells (RSCs). Blockage is initiated by IL-6-like oncokines that perturb renal water-transporting cells, and trigger a damage response in RSCs that proceeds pathologically. Thus, a chronic inflammatory state produced by the tumor causes paraneoplastic fluid dysregulation by altering cellular homeostasis of host renal units. Significance StatementTumors cause pathophysiological changes to host tissues, including distant organs. Here we use fruit fly cancer models to uncover mechanisms underlying paraneoplastic renal dysfunction. IL-6-like signaling from the tumor induces inflammatory signaling in renal tubule cells. Defects in these cells are sensed by normally quiescent renal stem cells, leading to inappropriate proliferation in a damage-like response. Chronic activation in the tumor context results in physical obstruction of tubule ducts and thus failures in fluid clearance. This fly work can prompt investigation of analogous mechanisms underlying renal dysfunction in cancer patients.

developmental biology↗

bioRxiv2022

Systemic coagulopathy drives host lethality in a new Drosophila tumor model

Malignant tumors trigger a complex network of inflammatory and wound repair responses, prompting Dvoraks characterization of tumors as wounds that never heal 1. Some of these responses lead to profound defects in blood clotting, such as Disseminated Intravascular Coagulopathy (DIC), which correlate with poor prognoses 2-4. Here, we demonstrate that a new tumor model in Drosophila provokes phenotypes that recapitulate coagulopathies observed in patients. Fly ovarian tumors overproduce multiple secreted components of the clotting cascade and trigger hypercoagulation of fly blood (hemolymph). Hypercoagulation occurs shortly after tumor induction and is transient; it is followed by a hypocoagulative state that is defective in wound healing. Cellular clotting regulators accumulate on the tumor over time and are depleted from the body, suggesting that hypocoagulation is caused by malignant growth exhaustion of host clotting components. Interestingly, clinical studies have suggested that lethality in patients with high serum levels of clotting components can be independent of thrombotic events 5,6. We show that rescuing coagulopathy improves survival of tumor-bearing flies, despite the fact that flies have an open circulatory system. Our work establishes a platform for identifying alternative mechanisms by which tumor-driven coagulopathy triggers early mortality, as well as exploring other conserved mechanisms of host responses to chronic wounds.

developmental biology↗

bioRxiv2022

Minimal functional domains of the core polarity regulator Dlg

The compartmentalized domains of polarized epithelial cells arise from mutually antagonistic actions between the apical Par complex and the basolateral Scrib module. In Drosophila, the Scrib module proteins Scribble (Scrib) and Discs-large (Dlg) are required to limit Lgl phosphorylation at the basolateral cortex, but how Scrib and Dlg could carry out such a protection activity is not clear. We tested Protein Phosphatase 1 (PP1) as a potential mediator of this activity but demonstrate that a significant component of Scrib and Dlg regulation of Lgl is PP1-independent and found no evidence for a Scrib-Dlg-PP1 protein complex. However, the Dlg SH3 domain plays a role in Lgl protection and, in combination with the N-terminal region of the Dlg HOOK domain, in recruitment of Scrib to the membrane. We identify a minimal Dlg comprised of the SH3 and HOOK domains that is both necessary and sufficient for Scrib localization and epithelial polarity function in vivo. Summary StatementA minimal SH3-HOOK fragment of Dlg is sufficient to support epithelial polarity through mechanisms independent of the PP1 phosphatase.

developmental biology↗

bioRxiv2021

Evidence for a Nuclear Role for Drosophila Dlg as a Regulator of the NURF Complex

Scrib, Dlg, and Lgl are basolateral regulators of epithelial polarity and tumor suppressors whose molecular mechanisms of action remain unclear. We used proximity biotinylation to identify proteins localized near Dlg in the Drosophila wing imaginal disc epithelium. In addition to expected membrane- and cytoskeleton-associated protein classes, nuclear proteins were prevalent in the resulting mass spectrometry data set, including all four members of the NURF chromatin remodeling complex. Subcellular fractionation demonstrated a nuclear pool of Dlg and proximity ligation confirmed its position near the NURF complex. Genetic analysis showed that NURF activity is also required for the overgrowth of dlg tumors, and this growth suppression correlated with a reduction in Hippo pathway gene expression. Together, these data suggest a nuclear role for Dlg in regulating chromatin and transcription through a more direct mechanism than previously thought. Highlight SummaryProximity proteomics is used as an entry point towards identifying partners of the polarity-regulating tumor suppressor Dlg. A nuclear pool of the protein associated with NURF chromatin remodelers is revealed, along with evidence of functional interactions during growth regulation.

cell biology↗

bioRxiv2019

Distinct activities of Scrib module proteins organize epithelial polarity

A polarized architecture is central to both epithelial structure and function. In many cells, polarity involves mutual antagonism between the Par complex and the Scrib module. While molecular mechanisms underlying Par-mediated apical determination are well-understood, how Scrib module proteins specify the basolateral domain remains unknown. Here, we demonstrate dependent and independent activities of Scrib, Dlg and Lgl using the Drosophila follicle epithelium. Our data support a linear hierarchy for localization, but rule out previously proposed protein-protein interactions as essential for polarization. Membrane recruitment of Scrib does not require palmitoylation or polar phospholipid binding but instead an independent cortically-stabilizing activity of Dlg. Scrib and Dlg do not directly antagonize aPKC, but may instead restrict aPKC localization by enabling the aPKC-inhibiting activity of Lgl. Importantly, while Scrib, Dlg and Lgl are each required, all three together are not sufficient to antagonize the Par complex. Our data demonstrate previously unappreciated diversity of function within the Scrib module and begin to define the elusive molecular functions of Scrib and Dlg. SIGNIFICANCE STATEMENTTo enable their physiological functions, cells must polarize their plasma membrane. In many epithelia, polarity is regulated by balanced activity of the apical Par complex and basolateral Scribble module. While the former is understood in molecular detail, little is known about how the latter works. We identify distinct functions of the three Scribble module proteins, separating independent roles in a localization hierarchy from cooperative roles in apical polarity antagonism and showing that they are not together sufficient to specify basolateral identity. This work establishes an essential basis for a mechanistic understanding of this core polarity machinery that controls processes ranging from stem cell divisions to organ morphogenesis across animal species.

developmental biology↗

bioRxiv2018

3D Tissue elongation via ECM stiffness-cued junctional remodeling

Organs are sculpted by extracellular as well as cell-intrinsic forces, but how collective cell dynamics are orchestrated in response to microenvironmental cues is poorly understood. Here we apply advanced image analysis to reveal ECM-responsive cell behaviors that drive elongation of the Drosophila follicle, a model 3D system in which basement membrane stiffness instructs tissue morphogenesis. Through in toto morphometric analyses of WT and round egg mutants, we find that neither changes in average cell shape nor oriented cell division are required for appropriate organ shape. Instead, a major element is a reorientation of elongated cells at the follicle anterior. Polarized reorientation is regulated by mechanical cues from the basement membrane, which are transduced by the Src tyrosine kinase to alter junctional E-cadherin trafficking. This mechanosensitive cellular behavior represents a conserved mechanism that can elongate edgeless tubular epithelia in a process distinct from those that elongate bounded, planar epithelia.

developmental biology↗

bioRxiv2017

High-risk Autism Spectrum Disorder Utah pedigrees: a novel Shared Genomic Segments analysis.

Progress in gene discovery for Autism Spectrum Disorder (ASD) has been rapid over the past decade, with major successes in validation of risk of predominantly rare, penetrant, de novo and inherited mutations in over 100 genes (de Rubies et al., 2015; Sanders et al., 2015). However, the majority of individuals with ASD diagnoses do not carry a rare, penetrant genetic risk factor. In fact, recent estimates suggest that most of the genetic liability of ASD is due to as yet undiscovered common, less penetrant inherited variation (Gaugler et al., 2014) which is much more difficult to detect. The study of extended, high-risk families adds significant information in our search for these common inherited risk factors. Here, we present results of a new, powerful pedigree analysis method (Shared Genomic Segments--SGS) on three large families from the Utah Autism Research Program. The method improves upon previous methods by allowing for within-family heterogeneity, and identifying exact region boundaries and subsets of cases who share for targeted follow-up analyses. Our SGS analyses identified one genome-wide significant shared segment on chromosome 17 (q21.32, p=1.47x10-8). Additional regions with suggestive evidence were identified on chromosomes 3, 4, 6, 8, 11, 13, 14, 15, and 18. Several of these segments showed evidence of sharing across families. Genes of interest in these regions include ATP8A1, DOCK3, CACNA2D2, ITGB3, AMBRA1, FOLH1, DGKZ, MTHFS, ARNT2, BTN2A2, BTN3A1, BTN3A3, BTN2A1, and BTN1A1. We are exploring multiple other lines of evidence to follow up these implicated regions and genes.

genetics↗