Biology subjects

Garrett, T.

Publications and source records attributed to Garrett, T..

15 recordsLinked to original sources

bioRxiv2026

Metabolomic changes underpinning permethrin resistance in the Anopheles gambiae malaria vector from Cameroon

Insecticide resistance reduces the effectiveness of current malaria vector control interventions. To understand the mechanisms underlying permethrin resistance in field-derived Anopheles gambiae vectors collected from Cameroon, we used Ultra-High Performance Liquid Chromatography coupled with High-Resolution Tandem Mass Spectrometry (UHPLC-HRMS/MS) to comprehensively analyze metabolic changes in resistant and susceptible samples to gain insight into mechanisms driven permethrin resistance. Resistant mosquitoes exhibited upregulated levels of inosine, nicotinic acid, dipeptides, amino acids, fumarate, uracil, and aldopentose. These data suggest that altered metabolic-based detoxification, as well as target site and metabolic shifts, and enhanced energy production contribute to permethrin resistance. Conversely, susceptible mosquitoes showed increased levels of N-acetyl-aspartic acid, xanthurenic acid, 2-hydroxyglutarate, 3-hydroxykynurenine, propanoylcarnitine, and L-pipecolic acid. These metabolites are associated with neurotoxicity, energy disruption, as well as tryptophan and lysine catabolism. These findings elucidate the metabolic pathways of permethrin-resistance and underscore the mechanisms that could lead to the emergence of pyrethroid cross-resistance.

systems biology↗

bioRxiv2025

Metformin decreases RAN proteins, rescues splicing abnormalities and improves behavioral phenotypes in SCA8 BAC mice

Spinocerebellar ataxia type 8 is one member of a larger group of dominantly inherited, debilitating neurological diseases caused by CTG*CAG expansions for which there are no effective disease-targeting treatments. RAN translation, which was discovered in SCA8, has previously been shown to occur across CAG and CUG expansion transcripts, making treatments that work for SCA8 potentially relevant to a much broader group of diseases, including SCA1, 2, 3, 6, 7, 12, Huntingtons Disease (HD) Fuchs endothelial corneal dystrophy (FECD), and myotonic dystrophy type 1 (DM1). The FDA-approved drug, metformin, has been previously shown to reduce RAN protein levels in cells overexpressing SCA8 CAG repeats. Here we show, using SCA8 BAC transgenic mice, that metformin treatment improves ambulatory performance, including rotarod, DigiGait, and open field measures. At the molecular level, metformin-treated mice show reduced RAN protein levels and improved splicing abnormalities without changing the levels of the expanded RNAs. Metformin-treated mice also show decreased neuroinflammation with reduced levels of astrogliosis and reduced numbers of activated microglia. Taken together, these data provide strong support for testing FDA-approved metformin in clinical trials for SCA8 and potentially the broader group of CAG*CTG repeat expansion disorders. One Sentence SummaryMetformin improves behavior, neuropathological and molecular phenotypes in SCA8 BAC transgenic mice.

neuroscience↗

bioRxiv2025

Discrepancies in Biomarker Identification in Different Peak-Picking Strategies in Untargeted Metabolomics Analyses of Cells, Tissues, and Biofluids

Different software and algorithms are available for peak picking in nontargeted metabolomics and each may have its own strengths and limitations. The choice of pick picking method can significantly influence the results obtained, including the number and identity of metabolites detected, their quantification, and subsequent biomarker analysis. The impact of peak picking by different tools in an untargeted metabolomics-based biomarker study is largely understated. This study compares two popular open-source software tools for peak picking in untargeted metabolomics of cancer cells, tissues, and bio-fluids: XCMS and MZmine 2. The investigation evaluates the impact of these peak-picking algorithms on biomarker identification. We found significant discrepancy between the results obtained from XCMS and MZmine 2, regardless of the sample types, solvent gradient phases, retention time (RT), or mass-to-charge ratio (m/z) tolerances used. Notably, this study revealed significant disagreement between peak picking tools in the context of metabolite-based biomarker study and highlights the importance of carefully evaluating and selecting appropriate peak picking tools to ensure reliable and accurate results in untargeted metabolomics research. O_FIG O_LINKSMALLFIG WIDTH=172 HEIGHT=200 SRC="FIGDIR/small/641559v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@af718dorg.highwire.dtl.DTLVardef@481bd4org.highwire.dtl.DTLVardef@1b10fborg.highwire.dtl.DTLVardef@f80215_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

bioRxiv2024

Intestinal serotonergic vagal signaling as a mediator of microbiota-induced hypertension

Hypertension is a pervasive global health challenge, impacting over a billion individuals worldwide. Despite strides in therapeutic strategies, a significant proportion of patients remain resistant to the currently available therapies. While conventional treatments predominantly focus on cardiac, renal, and cerebral targets, emerging research underscores the pivotal role of the gut and its microbiota. Yet, the precise mechanisms governing interactions between the gut microbiota and the host blood pressure remain unclear. Here we describe a neural host-microbiota interaction that is mediated by the intestinal serotonin (5-HT) signaling via vagal 5HT3a receptors and which is crucial for maintenance of blood pressure homeostasis. Notably, a marked decrease in both intestinal 5-HT and vagal 5HT3aR signaling is observed in hypertensive rats, and in rats subjected to fecal microbiota transplantation from hypertensive rats. Leveraging an intersectional genetic strategy in a Cre rat line, we demonstrate that intestinal 5HT3aR vagal signaling is a crucial link between the gut microbiota and blood pressure homeostasis and that recovery of 5-HT signaling in colon innervating vagal neurons can alleviate hypertension. This paradigm-shifting finding enhances our comprehension of hypertensive pathophysiology and unveils a promising new therapeutic target for combating resistant hypertension associated with gut dysbiosis.

physiology↗

bioRxiv2024

Pharmacologic Inhibition of Ferroptosis Attenuates Experimental Abdominal Aortic Aneurysm Formation

The pathogenesis of abdominal aortic aneurysm (AAA) formation involves vascular inflammation, thrombosis formation and programmed cell death leading to aortic remodeling. Recent studies have suggested that ferroptosis, an excessive iron-mediated cell death, can regulate cardiovascular diseases, including AAAs. However, the role of ferroptosis in immune cells, like macrophages, and ferroptosis-related genes in AAA formation remains to be deciphered. Single cell-RNA sequencing of human aortic tissue from AAA patients demonstrates significant differences in ferroptosis-related genes compared to control aortic tissue. Using two established murine models of AAA and aortic rupture in C57BL/6 (WT) mice, we observed that treatment with liproxstatin-1, a specific ferroptosis inhibitor, significantly attenuated aortic diameter, pro-inflammatory cytokine production, immune cell infiltration (neutrophils and macrophages), increased smooth muscle cell -actin expression and elastic fiber disruption compared to mice treated with inactivated elastase in both pre-treatment and treatment after a small AAA had already formed. Lipidomic analysis using mass spectrometry shows a significant increase in ceramides and a decrease in intact lipid species levels in murine tissue compared to controls in the chronic AAA model on day 28. Mechanistically, in vitro studies demonstrate that liproxstatin-1 treatment of macrophages mitigated the crosstalk with aortic smooth muscle cells (SMCs) by downregulating MMP2 secretion. Taken together, this study demonstrates that pharmacological inhibition by liproxstatin-1 mitigates macrophage-dependent ferroptosis contributing to inhibition of aortic inflammation and remodeling during AAA formation.

immunology↗

bioRxiv2024

Lipoxin A4/FPR2 signaling mitigates ferroptosis of alveolar epithelial cells via NRF2-dependent pathway during lung ischemia-reperfusion injury

BACKGROUNDPost-lung transplantation (LTx) injury can involve sterile inflammation due to ischemia-reperfusion injury (IRI). We investigated the cell-specific role of ferroptosis (excessive iron-mediated cell death) in mediating lung IRI and determined if specialized pro-resolving mediators such as Lipoxin A4 (LxA4) can protect against ferroptosis in lung IRI. METHODSSingle-cell RNA sequencing of lung tissue from post-LTx patients was analyzed. Lung IRI was evaluated in C57BL/6 (WT), formyl peptide receptor 2 knockout (Fpr2-/-) and nuclear factor erythroid 2-related factor 2 knockout (Nrf2-/-) mice using a hilar-ligation model with or without LxA4 administration. Furthermore, the protective efficacy of LxA4 was evaluated employing a murine orthotopic LTx model and in vitro studies using alveolar type II epithelial (ATII) cells. RESULTSDifferential expression of ferroptosis-related genes was observed in post-LTx patient samples compared to healthy controls. A significant increase in the levels of oxidized lipids and reduction in the levels of intact lipids were observed in mice subjected to IRI compared to shams. Furthermore, pharmacological inhibition of ferroptosis with liproxstatin-1 mitigated lung IRI and lung dysfunction. Importantly, LxA4 treatment attenuated pulmonary dysfunction, ferroptosis and inflammation in WT mice subjected to lung IRI, but not in Fpr2-/- or Nrf2-/-mice, after IRI. In the murine LTx model, LxA4 treatment increased PaO2 levels and attenuated lung IRI. Mechanistically, LxA4-mediated protection involves increase in NRF2 activation and glutathione concentration as well as decrease in MDA levels in ATII cells. CONCLUSIONSLxA4/FPR2 signaling on ATII cells mitigates ferroptosis via NRF2 activation and protects against lung IRI.

immunology↗

bioRxiv2022

A subtype of melanopsin ganglion cells encodes ground luminance

Visual input to the hypothalamus from intrinsically photosensitive retinal ganglion cells (ipRGCs) influences several functions including circadian entrainment, body temperature, and sleep. ipRGCs also project to nuclei such as the supraoptic nucleus (SON), which is involved in systemic fluid homeostasis, maternal behavior, and appetite. However, little is known about the SON-projecting ipRGCs or their relationship to well-characterized ipRGC subtypes. Using a GlyT2Cre mouse line, we identify a subtype of ipRGCs restricted to the dorsal retina that selectively project to the SON. These ipRGCs form a non-overlapping tiled mosaic that is limited to a dorsal region of the retina, forming a substrate for encoding ground luminance. Optogenetic activation of their axons demonstrates they release the neurotransmitter glutamate and that the SON is retinorecipient, receiving synaptic input from dorsal ipRGCs. Our results challenge the idea that ipRGC dendrites overlap to optimize photon capture and suggests non-image forming vision operates to sample local regions of the visual field.

neuroscience↗

bioRxiv2022

The coupling between healthspan and lifespan in Caenorhabditis depends on complex interactions between compound intervention and genetic background

Aging is characterized by declining health that results in decreased neuromuscular function and cellular resilience. The relationship between lifespan and health, and the influence of genetic background on that relationship, has important implications in the development of anti-aging interventions. Here we combined survival under thermal and oxidative stress with swimming performance, to evaluate health effects across a nematode genetic diversity panel for three compounds previously studied in the Caenorhabditis Intervention Testing Program - NP1, propyl gallate, and resveratrol. We show that oxidative stress resistance and thermotolerance vary with compound intervention, genetic background, and age. The effects of tested compounds on swimming locomotion, in contrast, are largely species-specific. Additionally, thermotolerance, but not oxidative stress or swimming ability, correlates with lifespan. Our results demonstrate the importance of assessing health and lifespan across genetic backgrounds in the effort to identify reproducible aging interventions.

physiology↗

bioRxiv2021

Antioxidants green tea extract and nordihydroguaiaretic acid confer species and strain specific lifespan and health effects in Caenorhabditis nematodes

The Caenorhabditis Intervention Testing Program (CITP) is an NIH-funded research consortium of investigators who conduct analyses at three independent sites to identify chemical interventions that reproducibly promote health and lifespan in a robust manner. The founding principle of the CITP is that compounds with positive effects across a genetically diverse panel of Caenorhabditis species and strains are likely engaging conserved biochemical pathways to exert their effects. As such, interventions that are broadly efficacious might be considered prominent compounds for translation for pre-clinical research and human clinical applications. Here, we report results generated using a recently streamlined pipeline approach for the evaluation of the effects of chemical compounds on lifespan and health. We studied five compounds previously shown to extend C. elegans lifespan or thought to promote mammalian health: 17-estradiol, acarbose, green tea extract, nordihydroguaiaretic acid, and rapamycin. We found that green tea extract and nordihydroguaiaretic acid extend Caenorhabditis lifespan in a species-specific manner. Additionally, these two antioxidants conferred assay-specific effects in some studies--for example, decreasing survival for certain genetic backgrounds in manual survival assays in contrast with extended lifespan as assayed using automated C. elegans Lifespan Machines. We also observed that GTE and NDGA impact on older adult mobility capacity is dependent on genetic background, and that GTE reduces oxidative stress resistance in some Caenorhabditis strains. Overall, our analysis of the five compounds supports the general idea that genetic background and assay type can influence lifespan and health effects of compounds, and underscores that lifespan and health can be uncoupled by chemical interventions.

physiology↗

bioRxiv2021

Sensitization of FOLFOX-resistant colorectal cancer cells via the modulation of a novel pathway involving protein phosphatase 2A

The treatment of colorectal cancer (CRC) with FOLFOX shows some efficacy, but these tumors quickly develop resistance to this treatment. We have observed an increased phosphorylation of AKT1/mTOR/4EBP1 and levels of p21 in FOLFOX-resistant CRC cells. We have identified a small molecule, NSC49L, that stimulates protein phosphatase 2A (PP2A) activity, downregulates the AKT1/mTOR/4EBP1-axis, and inhibits p21 translation. We have provided evidence that NSC49L- and TRAIL-mediated sensitization is synergistically induced in p21-knockdown CRC cells, which is reversed in p21-overexpressing cells. p21 binds with procaspase 3 and prevents activation of caspase 3. We have shown that TRAIL induces apoptosis through the activation of caspase 3 by NSC49L-mediated downregulation of p21 translation, and thereby cleavage of procaspase 3 into caspase 3. NSC49L does not affect global protein synthesis. These studies provide a mechanistic understanding of NSC49L as a PP2A agonist, and how its combination with TRAIL sensitizes FOLFOX-resistant CRC cells. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=127 SRC="FIGDIR/small/453259v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@bc3332org.highwire.dtl.DTLVardef@1c533b0org.highwire.dtl.DTLVardef@1c4a852org.highwire.dtl.DTLVardef@6aec2_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2021

Niclosamide reverses SARS-CoV-2 control of lipophagy

The global effort to combat COVID-19 rapidly produced a shortlist of approved drugs with anti-viral activities for clinical repurposing. However, the jump to clinical testing was lethal in some cases as a full understanding of the mechanism of antiviral activity as opposed to pleiotropic activity/toxicity for these drugs was lacking. Through parallel lipidomic and transcriptomic analyses we observed massive reorganization of lipid profiles of infected Vero E6 cells, especially plasmalogens that correlated with increased levels of virus replication. Niclosamide (NIC), a poorly soluble anti-helminth drug identified for repurposed treatment of COVID-19, reduced the total lipid profile that would otherwise amplify during virus infection. NIC treatment reduced the abundance of plasmalogens, diacylglycerides, and ceramides, which are required for virus production. Future screens of approved drugs may identify more druggable compounds than NIC that can safely but effectively counter SARS-CoV-2 subversion of lipid metabolism thereby reducing virus replication. However, these data support the consideration of niclosamide as a potential COVID-19 therapeutic given its modulation of lipophagy leading to the reduction of virus egress and the subsequent regulation of key lipid mediators of pathological inflammation.

microbiology↗

bioRxiv2019

Automated Lifespan Determination Across Caenorhabditis Strains and Species Reveals Assay-Specific Effects of Chemical Interventions

The goal of the Caenorhabditis Intervention Testing Program is to identify robust and reproducible pro-longevity interventions that are efficacious across genetically diverse cohorts in the Caenorhabditis genus. The project design features multiple experimental replicates collected by three different laboratories. Our initial effort employed fully manual survival assays. With an interest in increasing throughput, we explored automation with flatbed scanner-based Automated Lifespan Machines (ALMs). We used ALMs to measure survivorship of 22 Caenorhabditis strains spanning three species. Additionally, we tested five chemicals that we previously found extended lifespan in manual assays. Overall, we found similar sources of variation among trials for the ALM and our previous manual assays, verifying reproducibility of outcome. Survival assessment was generally consistent between the manual and the ALM assays, although we did observe radically contrasting results for certain compound interventions. We found that particular lifespan outcome differences could be attributed to protocol elements such as enhanced light exposure of specific compounds in the ALM, underscoring that differences in technical details can influence outcomes and therefore interpretation. Overall, we demonstrate that the ALMs effectively reproduce a large, conventionally scored dataset from a diverse test set, independently validating ALMs as a robust and reproducible approach towards aging-intervention screening.

physiology↗

bioRxiv2019

Re-modeling of foliar membrane lipids in a seagrass allows for growth in phosphorus deplete conditions

We used liquid chromatography high-resolution tandem mass spectrometry to analyze the lipidome of turtlegrass (Thalassia testudinum) leaves with extremely high phosphorus content and extremely low phosphorus content. Most species of phospholipids were significantly down-regulated in phosphorus-deplete leaves, whereas diacylglyceryltrimethylhomoserine (DGTS), triglycerides (TG), galactolipid digalactosyldiacylglycerol (DGDG), certain species of glucuronosyldiacylglycerols (GlcADG), and certain species of sulfoquinovosyl diacylglycerol (SQDG) were significantly upregulated, explaining the change in phosphorus content as well as structural differences in leaves of plants growing under diverse phosphate concentrations. These data suggest that seagrasses are able to modify the phosphorus content in leaf membranes dependent upon environmental phosphorus availability.

ecology↗

bioRxiv2019

Somatodendritic HCN channels in hippocampal OLM cells revealed by a convergence of computational models and experiments

Determining details of spatially extended neurons is a challenge that needs to be overcome. The oriens-lacunosum/moleculare (OLM) interneuron has been implicated as a critical controller of hippocampal memory making it essential to understand how its biophysical properties contribute to function. We previously used computational models to show that OLM cells exhibit theta spiking resonance frequencies that depend on their dendrites having hyperpolarization-activated cation channels (h-channels). However, whether OLM cells have dendritic h-channels is unknown. We performed a set of whole-cell recordings of OLM cells from mouse hippocampus and constructed multi-compartment models using morphological and electrophysiological parameters extracted from the same cell. The models matched experiments only when dendritic h-channels were present. Immunohistochemical localization of the HCN2 subunit confirmed dendritic expression. These models can be used to obtain insight into hippocampal function. Our work shows that a tight integration of model and experiment tackles the challenge of characterizing spatially extended neurons.

neuroscience↗

bioRxiv2019

Integrated RNA and metabolite profiling of urine liquid biopsies for prostate cancer biomarker discovery

Sensitive and specific diagnostic and prognostic biomarkers for prostate cancer (PCa) are urgently needed. Urine samples are a non-invasive means to obtain abundant and readily accessible \"liquid biopsies\". Herein we used urine liquid biopsies to identify and characterize a novel group of urine-enriched RNAs and metabolites in PCa patients and normal individuals with or without benign prostatic disease. Differentially expressed RNAs were identified in urine samples by deep sequencing and metabolites in urine were measured by mass spectrometry. The mRNA and metabolite profiles were distinct in patients with benign and malignant disease. Integrated analysis of urinary gene expression and metabolite signatures unveiled an aberrant glutamate metabolism and tricarboxylic acid (TCA) cycle node in prostate cancer-derived cells. Functional validation supports a role for glutamate metabolism and glutamate oxaloacetate transaminase 1 (GOT1)-dependent redox balance in prostate cancer, which can be exploited for novel biomarkers and therapies.

cancer biology↗