Biology subjects

Coowar, D.

Publications and source records attributed to Coowar, D..

7 recordsLinked to original sources

bioRxiv2026

Voluntary Exercise Differentially Affects High-Fat Induced Metabolic Phenotypes Across BXD Mouse Strains

Obesity and metabolic diseases such as diabetes reflect long-term interactions between diet, lifestyle, and genetics, variables that are hard to control in humans but can be systematically varied in mice, though behavioral variables like long-term exercise remain harder to model. Having previously phenotyped ~50 BXD strains, we identified BXD40, BXD43, and BXD100 as predisposed to voluntary wheel-running (~6 km/day at 24 weeks) with variable susceptibility to diet-induced obesity and diabetes. We followed these strains from 8-32 weeks on a 60% kcal/fat high-fat (HF) diet, with or without access to running wheels. Wheel usage declined from ~9 km/day in the first two weeks to a steady ~5 km/day thereafter yet still improved oral glucose tolerance by 35% over sedentary controls by 24 weeks. Despite equivalent body weight, runners ate 20% more relative to body weight, indicating the glucose benefit was independent of caloric intake. We next asked whether the gut microbiome contributes to this benefit. Long-term exercise produced only modest, cohort-dependent shifts in cecal microbial composition, though functional profiling revealed exercise-associated differences in carbohydrate- and glucose-metabolism pathways. Reciprocal bedding exchange between sedentary and running BXD43 cages reduced microbial differentiation in a taxon-specific manner and coincided with marked attenuation of the glucose phenotype, despite unchanged running behavior. Together, these findings validate BXD40, BXD43, and BXD100, alongside the canonical C57BL/6, as a model for studying diet, exercise, and genetics in metabolic disease, and implicate gut microbial taxa in shaping exercise's metabolic effects during HF feeding.

genetics↗

bioRxiv2025

Transcriptional Dysregulation in the Hippocampus of a murine model for Parkinson's Disease Cognition Impairment is Driven by Sex, Age, and Alpha-synuclein overexpression

Cognitive impairment is the most common and detrimental, but understudied non-motor symptom of Parkinsons disease (PD). Neuropathologically, it is associated with alpha-synuclein (Syn) misfolding and synapse loss in hippocampus and prefrontal cortex, leading to cognition loss and ultimately dementia. The molecular underpinnings of PD-associated cognitive dysfunction are unknown. In the present study, longitudinal gene expression profiling was performed to characterise molecular hippocampal alterations in a transgenic mouse overexpressing E46K mutated Syn, a model of early PD with loss of synaptophysin, a proxy marker of cognition, in hippocampus and cortex. Comparing 4 different ages of mice from both sexes showed that hippocampal gene expression changes were sexually dimorphic and strongly modulated by age and Syn overexpression. Pathways that emerged across different comparisons were connected to a variety of neuronal functions, collagen synthesis/remodelling, cellular stress, and inflammatory responses. The findings indicate that sex and age are essential covariates to consider when studying PD-associated cognitive decline. The uncovering of early events leading to disease in an animal model is an essential step toward prognostic biomarker identification and early interventions, which may have implications for monitoring, and for timing of therapeutic approaches.

neuroscience↗

bioRxiv2021

DJ-1 depletion slows down immunoaging in T-cell compartments

Decline in immune function during aging increases susceptibility to different aging related diseases. However, the underlying molecular mechanisms, especially the genetic factors contributing to imbalance of naive/memory T-cell subpopulations, still remain largely elusive. Here we show that loss of DJ-1 encoded by PARK7/DJ-1, causing early-onset familial Parkinsons disease (PD), unexpectedly delayed immunoaging in both human and mice. Compared with two gender-matched unaffected sibling carriers of similar ages, the index PD patient with DJ-1 deficiency showed a decline in many critical immunoaging features, including almost doubled frequencies of non-senescent T cells. The observation of a younger immune system in the index patient was further consolidated by the results in aged DJ-1 knockout mice. Our data from bone marrow chimera models and adoptive transfer experiments demonstrated that DJ-1 regulates several immunoaging features via hematopoietic-intrinsic and naive-CD8-intrinsic mechanisms. Our finding suggests an unrecognized critical role of DJ-1 in regulating immunoaging, discovering a potent target to interfere with immunoaging- and aging-associated diseases.

immunology↗

bioRxiv2020

Strain- and age-dependent features of the nigro-striatal circuit in three common laboratory mouse strains, C57BL/6J, A/J, and DBA/2J - Implications for Parkinson's disease modeling

Mouse models have been instrumental in understanding genetic determinants of aging and its crucial role in neurodegenerative diseases. However, few studies have analyzed the evolution of the mouse brain over time at baseline. Furthermore, mouse brain studies are commonly conducted on the C57BL/6 strain, limiting the analysis to a specific genetic background. In Parkinsons disease, the gradual demise of nigral dopaminergic neurons mainly contributes to the motor symptoms. Interestingly, a decline of the dopaminergic neuron function and integrity is also a characteristic of physiological aging in some species. Age-related nigro-striatal features have never been studied in mice of different genetic backgrounds. In this study, we analyze the morphological features in the striatum of three common mouse strains, C57BL/6J, A/J, and DBA/2J at 3-, 9- and 15 months of age. By measuring dopaminergic markers, we uncover age-related changes that differ between strains and evolve dynamically over time. Overall, our results highlight the importance of considering background strain and age when studying the murine nigro-striatal circuit in health and disease. HighlightsO_LIStudy of the integrity of the nigro-striatal circuit in C57BL/6J, A/J, and DBA/2J at different ages C_LIO_LIAge related evolution of essential features of nigral dopaminergic neurons differ between strains C_LIO_LIConsider background strain and age is crutial to study the nigrostriatal circuit in health and disease C_LI

neuroscience↗

bioRxiv2020

FAM13A regulates maturation and effector functions of natural killer cells

The polymorphism of the gene FAM13A (family with sequence similarity 13, member A) is strongly linked to the risk of lung cancer and chronic obstructive pulmonary disease, which are among the leading causes of mortality and morbidity in lung-related diseases worldwide. However, the underlying molecular and cellular mechanisms through which FAM13A contributes to the pathogenesis of these diseases largely remain unclear. Here, using a Fam13a knock out (KO) mouse model, we showed that Fam13a depletion upregulated the expression of the terminal differentiation and inhibitory marker, KLRG1 (killer cell lectin-like receptor G1) in natural killer (NK) cells. NK cells from Fam13a-deficient mice showed impaired IFN-{gamma} production either against target tumor cells or following various cytokine cocktail stimulations. Furthermore, the number of lung metastases induced by B16F10 melanoma cells was increased in Fam13a-KO mice. Collectively, our data suggest a key role of FAM13A in regulating NK cell functions, indicating that the key lung-disease risk gene FAM13A might contribute to the pathogenesis of several lung diseases via regulating NK cells.

immunology↗

bioRxiv2020

Neurodegeneration and neuroinflammation are linked, but independent of alpha-synuclein inclusions, in a seeding/spreading mouse model of Parkinson disease

A key process of neurodegeneration in Parkinson disease (PD) is the transneuronal spreading of alpha-synuclein. Alpha-synuclein is a presynaptic protein that is implicated in the pathogenesis of PD and other synucleinopathies, where it forms, upon intracellular aggregation, pathological inclusions. Other hallmarks of PD include neurodegeneration and microgliosis in susceptible brain regions. Whether it is primarily transneuronal spreading of alpha-synuclein particles, inclusion formation, or other mechanisms, such as inflammation, that cause neurodegeneration in PD is unclear. We used spreading/aggregation of alpha-synuclein induced by intracerebral injection of alpha-synuclein preformed fibrils into the mouse brain to address this question. We performed quantitative histological analysis for alpha-synuclein inclusions, neurodegeneration, and microgliosis in different brain regions, and a gene expression profiling of the ventral midbrain, at two different timepoints after disease induction. We observed significant neurodegeneration and microgliosis in brain regions not only with, but also without alpha-synuclein inclusions. We also observed prominent microgliosis in injured brain regions that did not correlate with neurodegeneration nor with inclusion load. In longitudinal gene expression profiling experiments, we observed early and unique alterations linked to microglial mediated inflammation that preceded neurodegeneration, indicating an active role of microglia in inducing neurodegeneration. Our observations indicate that alpha-synuclein inclusion formation is not the major driver in the early phases of PD-like neurodegeneration, but that diffusible, oligomeric alpha-synuclein species, which induce unusual microglial reactivity, play a key role in this process. Our findings uncover new features of alpha-synuclein induced pathologies, in particular microgliosis, and point to the necessity of a broader view of the process of prion-like spreading of that protein.

neuroscience↗

bioRxiv2019

PARK7/DJ-1 promotes pyruvate dehydrogenase activity and maintains Treg homeostasis

Pyruvate dehydrogenase (PDH) is the gatekeeper enzyme into the tricarboxylic acid (TCA) cycle. Here we show that PARK7/DJ-1, a key familial Parkinsons disease (PD) gene, is a pacemaker controlling PDH activity in CD4 regulatory T cells (Tregs). DJ-1 bound to PDH-E1 beta (PDHB), inhibiting the phosphorylation of PDH-E1 alpha (PDHA), thus promoting PDH activity and oxidative phosphorylation (OXPHOS). Dj-1 depletion impaired Treg proliferation and cellularity maintenance in older mice, increasing the severity during the remission phase of experimental autoimmune encephalomyelitis (EAE). The compromised proliferation and differentiation of Tregs in Dj-1 knockout mice were caused via regulating PDH activity. These findings provide novel insight into the already complicated regulatory machinery of the PDH complex and demonstrate that the DJ-1-PDHB axis represents a potent target to maintain Treg homeostasis, which is dysregulated in many complex diseases.

biochemistry↗