Biology subjects

Goodson, M. L.

Publications and source records attributed to Goodson, M. L..

3 recordsLinked to original sources

bioRxiv2025

Whey Protein Phospholipid Concentrate Supplementation Prevents High-Fat Diet Induced Cognitive Impairment in Wistar Rats by Promoting Brain Neuronal Connectivity and Sphingolipid Clearance

Whey protein phospholipid concentrate (WPPC), a byproduct of whey protein processing, is high in phospholipids and glycoconjugates which serve as substrates for fatty acids and sugar monomers (e.g. sialic acid) critical to neuronal myelin synthesis in the brain. This led us to hypothesize that WPPC will improve cognitive impairment induced by a high fat (HF) diet by promoting myelin turnover and improving myelin-dependent processes associated with encoding and storing memory. Male Wistar rats were randomized to one of four diets starting at weaning to [~]6.5 months on age: a low-fat (LF) diet containing 10% fat by weight, a HF diet containing 45% fat by weight to induce cognitive impairment, and a HF diet containing either 1.6% or 10% WPPC by weight (n=12 per diet). Rats were subjected to cognitive testing after 2 and 4 months of dietary intervention and then implanted with chronic bipolar electrodes to measure axonal evoked responses within the entorhinal cortex-hippocampal circuitry. Phospholipid and sphingolipid components of myelin were quantified in the hippocampus. There were no significant differences in cognition measured by novel object recognition after 2 months of supplementation. At 4 months, rats on the HF diet performed significantly worse than rats on the LF, HF1.6 and HF10 diets. The beneficial effects of WPPC on cognition were due to a partial reversal in evoked response impairments in hippocampal memory storage. Additionally, hippocampus sphingolipids were higher in rats on the HF diet compared to the LF, HF1.6 and HF10 groups. These findings demonstrate that WPPC prevented cognitive impairment induced by a HF diet by regulating entorhinal cortex-hippocampal circuitries associated with memory storage, though modulating myelin turnover.

neuroscience↗

bioRxiv2023

Activation of the aryl hydrocarbon receptor inhibits neuropilin-1 upregulation on IL-2 responding CD4+ T cells

Neuropilin-1 (Nrp1), a transmembrane protein expressed on CD4+ T cells, is mostly studied in the context of regulatory T cell (Treg) function. More recently, there is increasing evidence that Nrp1 is also highly expressed on activated effector T cells and that increases in these Nrp1-expressing CD4+ T cells correspond with immunopathology across several T cell-dependent disease models. Thus, Nrp1 may be implicated in the identification and function of immunopathologic T cells. Nrp1 downregulation in CD4+ T cells is one of the strongest transcriptional changes in response to immunoregulatory compounds that act though the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor. To better understand the link between AhR and Nrp1 expression on CD4+ T cells, Nrp1 expression was assessed in vivo and in vitro following AhR ligand treatment. In the current study, we identified that the percentage of Nrp1 expressing CD4+ T cells increases over the course of activation and proliferation in vivo. The actively dividing Nrp1+Foxp3- cells express the classic effector phenotype of CD44hiCD45RBlo, and the increase in Nrp1+Foxp3- cells is prevented by AhR activation. In contrast, Nrp1 expression is not modulated by AhR activation in non-proliferating CD4+ T cells. The downregulation of Nrp1 on CD4+ T cells was recapitulated in vitro in cells isolated from C57BL/6 and NOD (non-obese diabetic) mice. CD4+Foxp3- cells expressing CD25, stimulated with IL-2, or differentiated into Th1 cells, were particularly sensitive to AhR-mediated inhibition of Nrp1 upregulation. IL-2 was necessary for AhR-dependent downregulation of Nrp1 expression both in vitro and in vivo. Collectively, the data demonstrate that Nrp1 is a CD4+ T cell activation marker and that regulation of Nrp1 could be a previously undescribed mechanism by which AhR ligands modulate effector CD4+ T cell responses.

immunology↗

bioRxiv2023

Fibroblast growth factor-21 induces skeletal muscle atrophy and increases plasma amino acids in female mice: a potential role for glucocorticoids

BackgroundFibroblast growth factor-21 (FGF21) is an intercellular signaling molecule secreted by metabolic organs, including skeletal muscle, in response to intracellular stress. FGF21 crosses the blood brain barrier and acts via the nervous system to coordinate aspects of the adaptive starvation response, including increased lipolysis, gluconeogenesis, hepatic fatty acid oxidation, and activation of the hypothalamic-pituitary-adrenocortical (HPA) axis. Given its beneficial effects for hepatic lipid metabolism, pharmaceutical FGF21 analogues are in clinical trials treatment of fatty liver disease. We predicted pharmacologic treatment with FGF21 in-creases HPA axis activity and skeletal muscle glucocorticoid signaling and induces skeletal muscle atrophy in mice. MethodsWe treated male and female mice with FGF21 or saline, delivered either pe-ripherally or directly to the brain, to determine its effect on skeletal muscle. To identify metabolic pathways affected by FGF21, we analyzed untargeted primary metabolites measured in plasma by GCTOF-MS. To determine mechanisms underlying sex-and FGF21-dependent changes in muscle mass, we measured hormonal and molecular mediators of muscle protein synthesis and degradation. We performed stable isotope labeling with deuterium oxide to directly measure muscle protein synthesis. ResultsA short course of systemic FGF21 treatment decreased muscle protein synthe-sis (P < 0.001) and reduced tibialis anterior weight (P < 0.05); this was driven primarily by its effect in female mice (P < 0.05). Similarly, intracerebroventricular FGF21 reduced TA muscle fiber cross sectional area (P < 0.01); this was more apparent among female mice compared to male littermates (P < 0.05). In agreement with the reduced muscle mass, the topmost enriched meta-bolic pathways in FGF21-treated females were related to amino acid metabolism, and the relative abundance of plasma proteinogenic amino acids were increased up to three-fold (P < 0.05). FGF21 treatment increased hypothalamic Crh mRNA (P < 0.01), plasma corticosterone (P < 0.01), and adrenal weight (P < 0.05), and increased expression of glucocorticoid receptor target genes known to reduce muscle protein synthesis and/or promote degradation including Foxo1, Redd1, and Klf15 (P < 0.05). Again, these changes were driven primarily by effects of FGF21 in females (P < 0.05). ConclusionsFGF21 increased plasma amino acids and decreased skeletal muscle mass, together with activation of the HPA axis and glucocorticoid receptor target genes in skeletal muscle--and female mice were more sensitive to all these outcomes. Given the proposed use of FGF21 analogues for the treatment of metabolic disease, the study is both physiologically relevant and may have important clinical implications.

physiology↗