Biology subjects

Reed, L.

Publications and source records attributed to Reed, L..

4 recordsLinked to original sources

bioRxiv2026

The Metabolome of Drosophila Reveals Exercise-Induced Stress and Anti-Inflammatory Response

Exercise is a known remedy for metabolic disorders, including obesity and type II diabetes. In humans and some model organisms, exercise is classified into different types and intensities based on the mode of exercise and the devices used. Since Drosophila has emerged as a model for exercise research, several devices have been developed for exercise training. These devices vary in mechanisms of operation; for example, the Power Tower (PT) uses a repeated drop-and-hit mechanism, and the TreadWheel (TW) uses end-over-end rotation. This variation in mechanisms that trigger the negative geotaxis of flies could impact exercise outcomes, and it remains unclear how this variation drives the response of flies to exercise training. Stress is a known response to exercise in humans and mice. Stress in Drosophila can be induced by various conditions, including heat, cold, chemical exposure, and other environmental stressors, but there is little information on exercise-induced stress. It is also unclear whether different devices elicit distinct stress responses or whether the exercise-induced stress response is similar to other stress responses (e.g., thermal, chemical). To explore the effects of device, sex, and genotype on multiple metabolic pathways, we used an untargeted metabolomics approach to further elucidate the molecular mechanisms of exercise. As no studies have directly examined the exercise metabolome of Drosophila, this study is the first to explore the metabolome of flies post-exercise. Our results revealed that exercising on different devices elicits varying responses and reshapes the metabolome of flies. We also identified specific small compounds that may be linked to stress and inflammatory response more in the PT-exercised flies than in the TW-exercised flies. Overall, the exercise device effect interacted with sex effect and genotype, such that male and female flies have different metabolite compositions post-exercise on TW and PT.

Molecular Biology↗

bioRxiv2023

Heterozygous Kmt2d loss diminishes enhancers to render medulloblastoma cells vulnerable to combinatory inhibition of lysine demethylation and oxidative phosphorylation

The histone H3 lysine 4 (H3K4) methyltransferase KMT2D (also called MLL4) is one of the most frequently mutated epigenetic modifiers in medulloblastoma (MB) and many other types of cancer. Notably, heterozygous loss of KMT2D is prevalent in MB and other cancer types. However, what role heterozygous KMT2D loss plays in tumorigenesis has not been well characterized. Here, we show that heterozygous Kmt2d loss highly promotes MB driven by heterozygous loss of the MB suppressor gene Ptch in mice. Heterozygous Kmt2d loss upregulated tumor-promoting programs, including oxidative phosphorylation and G-protein-coupled receptor signaling, in Ptch+/--driven MB genesis. Mechanistically, both downregulation of the transcription-repressive tumor suppressor gene NCOR2 by heterozygous Kmt2d loss and upregulation of the oncogene MycN by heterozygous Ptch loss increased the expression of tumor-promoting genes. Moreover, heterozygous Kmt2d loss extensively diminished enhancer signals (e.g., H3K27ac) and H3K4me3 signature, including those for tumor suppressor genes (e.g., Ncor2). Combinatory pharmacological inhibition of oxidative phosphorylation and the enhancer-decommissioning H3K4 demethylase LSD1 drastically reduced tumorigenicity of MB cells bearing heterozygous Kmt2d loss. These findings reveal the mechanistic basis underlying the MB-promoting effect of heterozygous KMT2D loss, provide a rationale for a therapeutic strategy for treatment of KMT2D-deficient MB, and have mechanistic implications for the molecular pathogenesis of other types of cancer bearing heterozygous KMT2D loss.

cancer biology↗

bioRxiv2023

Investigating the phylogenetic history of toxin tolerance in mushroom-feeding Drosophila

Understanding how and when key novel adaptations evolved is a central goal of evolutionary biology. Within the immigrans-tripunctata radiation of Drosophila, many mushroom-feeding species are tolerant of host toxins, such as cyclopeptides, that are lethal to nearly all other eukaryotes. In this study, we used phylogenetic and functional approaches to investigate the evolution of cyclopeptide tolerance in the immigrans-tripunctata radiation of Drosophila. We first inferred the evolutionary relationships among 48 species in this radiation using 978 single copy orthologs. Our results resolved previous incongruities within species groups across the phylogeny. Second, we expanded on previous studies of toxin tolerance by assaying 16 of these species for tolerance to -amanitin and found that six of these species could develop on diet with toxin. Third, we examined fly development on a diet containing a natural mix of toxins extracted from the Death Cap Amanita phalloides mushroom. Both tolerant and susceptible species developed on diet with this mix, though tolerant species survived at significantly higher concentrations. Finally, we asked how cyclopeptide tolerance might have evolved across the immigrans-tripunctata radiation and inferred that toxin tolerance was ancestral and subsequently lost multiple times. Our results suggest the evolutionary history of cyclopeptide tolerance is complex, and simply describing this trait as present or absent does not fully capture the occurrence or impact on this adaptive radiation. More broadly, the evolution of novelty can be more complex than previously thought, and that accurate descriptions of such novelties are critical in studies examining their evolution.

evolutionary biology↗

bioRxiv2018

A novel bioreactor technology for modelling fibrosis in human and rodent precision-cut liver slices.

Summary boxO_LIWhat is already known about this subject?\nO_LICurrently there are no effective anti-fibrotic drugs to treat liver fibrosis and there is an urgent unmet need to increase our knowledge of the disease process and develop better tools for anti-fibrotic drug discovery.\nC_LIO_LIPreclinical in vitro cell cultures and animal models are widely used to study liver fibrosis and test anti-fibrotic drugs, but have shortfalls; cell culture models lack the relevant complex cell-cell interactions of the liver and animal models only reproduce some features of human disease.\nC_LIO_LIPrecision Cut Liver Slices (PCLS) are structurally representative of the liver and can be used to model liver fibrosis and test anti-fibrotic drugs. However, PCLS are typically cultured in elevated, non-physiological oxygen levels and only have a healthy lifespan of 48h.\nC_LI\nC_LIO_LIWhat are the new findings?\nO_LIWe have developed a novel bioreactor culture system that increases the longevity of functional PCLS to up to 6 days under normoxic conditions.\nC_LIO_LIBioreactor cultured PCLS can be used to model fibrogenesis in both normal and fibrotic PCLS using a combination of biochemical and histological outputs.\nC_LIO_LIAdministration of an Alk5 inhibitor effectively limits fibrogenesis in normal rodent and human PCLS and in rodent PCLS with established fibrosis.\nC_LI\nC_LIO_LIHow might it impact on clinical practice in the foreseeable future?\nO_LIThe extended longevity of bioreactor cultured PCLS represent a novel pre-clinical tool to investigate the cellular and molecular mechanisms of liver fibrosis.\nC_LIO_LIBioreactor cultured human PCLS offer a clinically relevant system to test efficacy of anti-fibrotic drugs.\nC_LI\nC_LI\n\nAbstractO_ST_ABSObjectiveC_ST_ABSPrecision cut liver slices (PCLS) retain the structure and cellular composition of the native liver and represent an improved system to study liver fibrosis compared to two-dimensional mono or co-cultures. The objective of this study was to develop a bioreactor system to increase the healthy lifespan of PCLS and model fibrogenesis.\n\nDesignPCLS were generated from normal rat or human liver, or 4-week carbon tetrachloride-fibrotic rat liver and cultured in our patented bioreactor. PCLS function was quantified by albumin ELISA. Fibrosis was induced in PCLS by TGF{beta}1 and PDGF{beta}{beta} stimulation. Alk5 inhibitor therapy was used. Fibrosis was assessed by fibrogenic gene expression, Picrosirius Red and Smooth Muscle Actin staining, hydroxyproline assay and collagen 1a1, fibronectin and hyaluronic acid ELISA.\n\nResultsBioreactor cultured PCLS are viable, maintaining tissue structure and stable albumin secretion for up to 6 days under normoxic culture conditions. Conversely, standard static transwell cultured PCLS rapidly deteriorate and albumin secretion is significantly impaired by 48 hours. TGF{beta}1 and PDGF{beta}{beta} stimulation of rat or human PCLS induced fibrogenic gene expression, release of extracellular matrix proteins, activation of hepatic myofibroblasts and histological fibrosis. Fibrogenesis slowly progresses over 6-days in cultured fibrotic rat PCLS without exogenous challenge. Alk5 inhibitor limited fibrogenesis in both TGF{beta}1 and PDGF{beta}{beta} stimulated PCLS and fibrotic PCLS.\n\nConclusionWe describe a new bioreactor technology which maintains functional PCLS cultures for 6 days. Bioreactor cultured PCLS can be successfully used to model fibrogenesis and demonstrate efficacy of an anti-fibrotic therapy.

cell biology↗