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Korgan, A. C.

Publications and source records attributed to Korgan, A. C..

2 recordsLinked to original sources

Hypothalamic gene network dysfunction is associated with cognitive decline and body weight loss in Alzheimer's disease mice

Recent studies, both clinical and experimental, indicate that many neurodegenerative disorders including Alzheimers disease (AD) often display coexisting metabolic dysfunctions, which may exacerbate neurological symptoms. The hypothalamus is a brain region highly involved in maintaining metabolic and other homeostatic processes and is known to be involved in the etiology of AD, although the role of hypothalamic dysfunction in the onset, progression, and severity of AD is poorly understood. In this study, we demonstrate that our new model of genetic diversity in AD, the AD-BXDs, exhibits non-cognitive symptoms consistent with hypothalamic dysfunction and examined hypothalamic bulk RNA sequencing data in the AD-BXD panel to investigate how the AD transgene impacts gene expression profiles in the hypothalamus. Mostly notably, we identified strong neuroinflammatory signatures from the hypothalamus in the AD-BXDs as early as six months of age. A functionally unknown WGCNA module showed correlation to female body weight and contextual fear acquisition. Eigengene expression of microglial/macrophagic modules and their hub gene expressions were correlated to cognitive phenotypes. From these analyses, we nominated Plek and Laptm5 as new targets to attenuate neuroinflammation in AD.

neuroscience↗

High-fat diet induced loss of GABAergic inhibition decouples intrinsic and synaptic excitability in AgRP neurons

Obesity is a progressive, relapsing disease with few therapies. Diet and lifestyle interventions are effective but are often temporary and many individuals regain weight. High-fat diet increases the excitability of AgRP neurons, a critical neuronal population for the regulation of food intake and body weight. Here we investigate the plasticity of AgRP neurons and the impact of high-fat diet on modulation by synaptic input. We find that diet-induced hyperexcitability of AgRP neurons is not reversed by a lower-fat diet intervention. High-fat diet is associated with changes in the synaptic modulation of AgRP neurons, with a paradoxical increase in inhibitory input accompanied by a loss of GABA-mediated inhibition due to a depolarizing shift in the reversal potential of the GABA-evoked Cl- current. These findings reveal that high-fat diet leads to decoupling of intrinsic and synaptic excitability in AgRP neurons, such that hyperexcitability of AgRP neurons persists despite an increase in inhibitory input, revealing a mechanism for the difficulty in sustaining weight loss.

neuroscience↗