Biology subjects

McCoin, C.

Publications and source records attributed to McCoin, C..

4 recordsLinked to original sources

bioRxiv2026

Dysregulation of xenobiotic metabolism and mitochondrial dysfunction exacerbate acetaminophen-induced hepatotoxicity in human antigen R-deficient male mice

Acetaminophen (APAP) overdose is a leading cause of acute liver failure worldwide. The RNA-binding protein Human antigen R (HuR) is a multifunctional post-transcriptional regulator that plays a pivotal role in cellular stress responses, including those triggered by APAP toxicity. This study investigated the mechanisms by which HuR protects against APAP-induced hepatotoxicity in male mice. Hepatocyte-specific HuR-deficient (HuRHep-/-) male mice on a C57BL/6N background and wild-type (WT) littermates were treated with 200 mg/kg APAP, and liver tissues were collected at 2, 6, and 24 hours post-treatment. APAP administration increased hepatic HuR mRNA expression and induced HuR cleavage and the formation of a higher-molecular weight HuR-immunoreactive band, with the latter two correlating with injury severity. Compared with WT controls, HuRHep-/- mice exhibited markedly increased susceptibility to hepatotoxicity at both 2 and 6 hours. Metabolite profiling revealed altered APAP metabolism and reduced glutathione S-transferase (Gst) expression in HuRHep-/- livers, consistent with impaired APAP detoxification and increased APAP-protein adduct formation. Fourier-transform infrared (FTIR) spectroscopy further identified early biochemical differences between WT and HuRHep-/- livers as early as 2 hours after APAP exposure. Additionally, HuR deficiency resulted in pronounced mitochondrial structural abnormalities and dysfunction at 2 and 6 hours, accompanied by reduced expression of the mitochondrial fission and fusion proteins Drp1 and Mfn2, increased mitochondrial protein release, and enhanced hepatocyte death. Although pro-inflammatory cytokine levels were elevated in HuRHep-/- mice relative to WT controls at 24 hours, hepatocyte proliferation was similarly blunted in both genotypes, consistent with severe liver injury and delayed recovery. Collectively, these findings identify hepatocyte HuR as a critical regulator of xenobiotic metabolism and mitochondrial integrity and establish its essential role in early protection against APAP-induced hepatotoxicity in male mice.

pharmacology and toxicology↗

bioRxiv2025

Age-dependent remodeling of the sciatic proteome in 5xFAD mice can be attenuated by exercise or donepezil treatment to maintain neuromuscular function

Background: Alzheimers disease (AD) progresses along a continuum for years to possibly decades prior to cognitive decline and clinical diagnosis. Preclinical AD is associated with neuromuscular dysfunction. We previously characterized early neuromuscular impairment prior to cognitive decline at 4 months of age in the 5xFAD mouse model of AD. However, the underlying cause(s) for peripheral nerve dysfunction leading to impaired skeletal muscle torque production are not understood, therefore limiting interventional capacity. We hypothesized that either voluntary wheel running or donepezil treatment, begun prior to neuromuscular decline, would delay manifestation of neuromuscular impairment in 5xFAD mice. Methods: Sciatic nerves from 5xFAD and wild-type (WT) mice were analyzed by tandem mass tag (TMT)-labeled proteomics at 3, 4, and 7 months to investigate proteome remodeling. Separate cohorts, using 3-month-old 5xFAD mice and WT littermates given voluntary wheel access for 4 weeks or treated with the acetylcholinesterase inhibitor donepezil to test if neuromuscular dysfunction could be attenuated. Afterwards, we assessed tibial nerve stimulated plantar flexion torque and sciatic nerve compound (motor) neuron action potential (CNAP) in-vivo at 4 months. Additionally, we performed TMT-labeled proteomics to ascertain the effect of exercise and donepezil treatments on sciatic proteome. Results: Sciatic nerves in 5xFAD mice exhibited proteomic remodeling from 3 to 4 months, particularly in pathways linked to mitochondrial turnover, calcium handling, lipid metabolism, and inflammation, coinciding with onset of neuromuscular dysfunction. Both exercise and donepezil attenuated in nerve-stimulated muscle torque and CNAP dysfunction. Both exercise and donepezil attenuated proteomic remodeling of the sciatic nerve involving mitochondrial-centric processes through both shared and independent mechanisms. Conclusions: Declines in neuromuscular function may be pre-clinical identifiers for AD that share pathway similarities with noted central effects of the pathology on the brain. Our findings highlight the importance of a systemic approach to AD pathology and importance of disease state in interventional efficacy. Graphical abstract.Created in Biorender. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=137 SRC="FIGDIR/small/662603v1_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@c41009org.highwire.dtl.DTLVardef@1f8d8e8org.highwire.dtl.DTLVardef@689ba5org.highwire.dtl.DTLVardef@1c28884_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2025

Proteomic and metabolic profiling reveals APOE4-dependent shifts in whole brain, neuronal, and astrocytic mitochondrial function and glycolysis

Apolipoprotein E (APOE) genetic variation is the strongest genetic risk factor for late onset Alzheimers disease (LOAD). Studies on APOE genotype dependent changes have largely focused on amyloid beta (A{beta}) aggregation, disease pathology, and lipid metabolism. Recently, there has been increased interest in the relationship between metabolic function and APOE genetic variation. In this study, we examined how APOE genotype can alter metabolism in the brains of young male and female APOE3 and APOE4 targeted replacement (TR) mice. In combination with this, we also examined cell type-specific differences using induced pluripotent stem cell (iPSC) derived astrocytes and neurons. We found sex and genotype dependent changes to metabolism in the brains of young APOE TR mice. Specifically, APOE4 mice show signs of metabolic stress and compensatory mechanisms in the brain. Using proteomics and stable isotope tracing metabolomics, we found that APOE4 iAstrocytes and iNeurons exhibit signs of inflammation, mitochondrial dysfunction, altered TCA cycle and malate-aspartate shuttle activity, and a metabolic shift toward glycolysis. Taken together, this data indicates APOE4 causes early changes to metabolism within the central nervous system. While this study establishes a relationship between APOE genotype and alterations in bioenergetics, additional studies are needed to investigate underlying mechanisms.

neuroscience↗

bioRxiv2024

A repeatedly evolved mutation in Cryptochrome-1 of subterranean animals alters behavioral and molecular circadian rhythms

The repeated evolution of similar phenotypes in independent lineages often occurs in response to similar environmental pressures, through similar or different molecular pathways. Recently, a repeatedly occurring mutation R263Q in a conserved domain of the protein Cryptochrome-1 (CRY1) was reported in multiple species inhabiting subterranean environments. Cryptochromes regulate circadian rhythms, and glucose and lipid metabolism. Subterranean species show changes to their circadian rhythm and metabolic pathways, making it likely that this mutation in CRY1 contributes to adaptive phenotypic changes. To identify the functional consequences of the CRY1 R263Q mutation, we generated a mouse model homozygous for this mutation. Indirect calorimetry experiments revealed delayed energy expenditure, locomotor activity and feeding patterns of mutant mice in the dark phase, but no further metabolic phenotypes - unlike a full loss of function of CRY1. Gene expression analyses showed altered expression of several canonical circadian genes in the livers of the mutant mice, fortifying the notion that CRY1 R263Q impacts metabolism. Our data provide the first characterization of a novel mutation that has repeatedly evolved in subterranean environments, supporting the idea that shared environmental constraints can drive the evolution of similar phenotypes through similar genetic changes.

evolutionary biology↗