Biology subjects

Kalsbeek, A.

Publications and source records attributed to Kalsbeek, A..

4 recordsLinked to original sources

bioRxiv2025

Neuropathological changes in the nucleus basalis of Meynert in people with type 1 or type 2 diabetes mellitus.

People with type 1 or type 2 diabetes mellitus (T1DM or T2DM) often experience cognitive impairment. We profiled cells in the nucleus basalis of Meynert (NBM) in postmortem human brain tissues to investigate neuropathological changes. 71 postmortem NBM samples were grouped by T1DM, T2DM and non-diabetic controls, with Braak stage 0-2 or 3-6. T1DM subjects had only Braak stage 0-2 and were thus compared only to controls with a similar Braak stage and not subjects with Braak stage 3-6. We analysed neurons expressing choline acetyltransferase (ChAT), phosphorylated-Tau, glial cells and vasculature with respective markers. We found significantly less neuronal expression of ChAT in T1DM compared to controls and T2DM with Braak stage 0-2. Later-stage hyperphosphorylated-Tau levels were higher in T2DM compared to controls with Braak stages 3-6. Our results suggest that reduced acetylcholine production by NBM neurons might underlie the cognitive complains of people with T1DM. In contrast, T2DM may exacerbate neuropathological changes associated with Alzheimers disease-like alterations.

neuroscience↗

bioRxiv2024

Targeted activation of microglial PPARdelta reprograms immunometabolism and enhances insulin sensitivity in diet-induced obesity.

Microglia play a crucial role in maintaining neuronal health through phagocytosis, a function that becomes compromised during diet-induced obesity and is associated with altered lipid metabolism. Previous research demonstrated that disrupting lipid metabolism in microglia, such as through lipoprotein lipase deficiency, impairs their phagocytic function and exacerbates obesity, glucose dysregulation, and hypothalamic neuron dysfunction. This study investigated whether enhancing lipid metabolism via peroxisome proliferator-activated receptor delta (PPAR{delta}) activation could counteract obesity-related metabolic disturbances. Thermal proteome profiling identified GW0742 as the most potent PPAR{delta} ligand among those tested. GW0742 enhanced microglial phagocytosis, reduced inflammation, and shifted energy metabolism towards glycolysis over oxidative phosphorylation. Targeted delivery of GW0742 using nanoparticles (NPs-GW0742) to microglia in the mediobasal hypothalamus of obese rats significantly improved insulin sensitivity without affecting body weight or food intake. Enhanced microglial activation was evidenced by increased soma size and coverage. These findings underscore the importance of microglial lipid metabolism in systemic glucose regulation and highlight the potential of PPAR{delta}-targeted therapies to mitigate hypothalamic inflammation and improve metabolic health in obesity.

neuroscience↗

bioRxiv2024

Limited microglial metabolic improvement with time-restricted feeding in diet-induced obesity

Time-restricted eating has shown promise for improving metabolic health in obese humans via incompletely resolved mechanisms. In this study, we investigated how time-restricted feeding (TRF) at different times of the day affects microglial immunometabolism using Wistar rats. We found that in high-fat diet (HFD)-fed obese rats, TRF during the active phase reduced fat mass, altered rhythmicity of the microglial transcriptome, and prevented an increase in hypothalamic microglia. These effects were dampened or absent with TRF during the resting phase. However, a HFD-induced microglial immunometabolic phenotype, characterized by reduced electron transport chain and increased lipid metabolism gene expression, and metabolic inflexibility, was not reversed by TRF in either the active or resting phase, indicating that reprogrammed microglial metabolism in obesity is a persistent cellular functional change that requires further study.

immunology↗

bioRxiv2023

An integrated single-cell RNA-seq atlas of the mouse hypothalamic paraventricular nucleus links transcriptional and functional types

The hypothalamic paraventricular nucleus (PVN) is a highly complex brain region that is crucial for homeostatic regulation through neuroendocrine signalling, outflow of the autonomic nervous system, and projections to other brain areas. The past years, single-cell datasets of the hypothalamus have contributed immensely to the current understanding of the diverse hypothalamic cellular composition. While the PVN has been adequately classified functionally, its molecular classification is currently still insufficient. To address this, we created a detailed atlas of PVN transcriptional cell types by integrating various PVN single-cell datasets into a recently published hypothalamus single-cell transcriptome atlas. Furthermore, we functionally profiled transcriptional cell types, based on relevant literature, existing retrograde tracing data and existing single-cell data of a PVN-projection target region. In our PVN atlas dataset, we identify the well-known different neuropeptide types, each composed of multiple novel subtypes. We identify Avp-Tac1, Avp-Th, Oxt-Foxp1, Crh-Nr3c1 and Trh-Nfib as the most important neuroendocrine subtypes based on markers described in literature. To characterize the pre-autonomic functional population, we integrated a single-cell retrograde tracing study of spinally-projecting pre-autonomic neurons into our PVN atlas. We identify these (pre-sympathetic) neurons to co-cluster with the Adarb2 + clusters in our dataset. Finally, we identify expression of receptors for Crh, Oxt, Penk, Sst, and Trh in the dorsal motor nucleus of the vagus, a key region that pre-parasympathetic PVN neurons project to. Concluding, our study present a detailed overview of the transcriptional cell types of the murine PVN, and provides a first attempt to resolve functionality for the identified populations.

neuroscience↗