Biology subjects

Garcia-Caceres, C.

Publications and source records attributed to Garcia-Caceres, C..

8 recordsLinked to original sources

bioRxiv2025

Neural CXCR4 contributes to neuroimmune modulation of atherosclerosis in a cardio-metabolic Ldlr-/- mouse model

BackgroundAtherosclerosis is a chronic inflammatory disease characterized by metabolic and immune dysregulation. Emerging evidence suggests that specific central nervous system (CNS) regions modulate its progression via neuroimmune cardiovascular interfaces (NICIs). While the C-X-C motif chemokine receptor 4 (CXCR4) is known to participate in atherogenesis by regulating immune cell dynamics and vascular wall responses, the role of neural CXCR4 in atherosclerotic plaque formation remains unclear. MethodsWe generated a Nestin-Cre-mediated conditional Cxcr4 knockout mouse model on a low-density lipoprotein receptor-deficient (Ldlr-/-) background and fed these mice a western diet (WD) for up to 12 weeks to induce atherosclerosis. To evaluate the impact of neural CXCR4 function, we quantified atherosclerotic plaque burden, systemic metabolic parameters and circulating immune cell profiles, comparing neural Cxcr4-deficient mice with corresponding genetic controls. Spatial transcriptomics and RNAscope were employed to map Cxcr4 mRNA and its non-canonical ligand macrophage migration inhibitory factor (Mif) mRNA in neuroimmune-regulatory brain regions, and to assess diet-induced expression changes in relation to neuroinflammatory responses. ResultsNeural conditional deletion of Cxcr4 in Ldlr-/- mice significantly reduced atherosclerotic plaque formation in the aortic arch and aorta, without affecting body weight, lipid levels, glucose tolerance, or circulating immune cells. Cxcr4 gene expression was found to be uniformly low across hypothalamic subregions implicated in neuroimmune regulation of systemic inflammation and atherogenesis. Importantly, WD feeding did not modify this consistently low expression in male Ldlr-/- mice. In contrast, Mif mRNA expression was significantly upregulated in the PVN after 5-day WD feeding, but not after 8 weeks. Exploratory spatial transcriptomic analysis of PVN-containing coronal brain sections from male Ldlr-/- mice suggested that 5-day WD exposure is associated with MIF-CXCR4 signaling and downstream neuroinflammatory pathways in the PVN. ConclusionsThis study identifies neural CXCR4 as a component of neuroimmune modulation in atherosclerosis, exerting its effect independently of systemic metabolic or inflammatory changes. Short-term WD exposure activated gene expression of the CXCR4 ligand Mif in the PVN, pointing to a neuroimmune axis that may promote vascular inflammation and atherosclerotic plaque development. These findings establish a link between CNS CXCR4 and vascular disease and suggest that MIF-CXCR4-dependent neuroimmune pathways may play a role in cardiometabolic risk. Trial registrationNot applicable.

immunology↗

bioRxiv2022

Coupling of oxytocin and cholecystokinin pathways in the hypothalamus is required for gut-to-brain homeostatic feeding control

Oxytocin-expressing paraventricular hypothalamic neurons (PVNOT neurons) integrate afferent signals from the gut including cholecystokinin (CCK) to adjust whole-body energy homeostasis. However, the molecular underpinnings by which PVNOT neurons orchestrate gut-to-brain feeding control remain unclear. Here, we show that mice undergoing selective ablation of PVNOT neurons fail to reduce food intake in response to CCK and develop hyperphagic obesity on chow diet. Notably, exposing wildtype mice to a high-fat/high-sugar (HFHS) diet recapitulates this insensitivity towards CCK, which is linked to diet-induced transcriptional and electrophysiological aberrations specifically in PVNOT neurons. Restoring OT pathways in DIO mice via chemogenetics or polypharmacology sufficiently re-establishes CCKs anorexigenic effects. Lastly, by single-cell profiling, we identify a specialized PVNOT neuronal subpopulation with increased {kappa}-opioid signaling under HFHS diet, which restrains their CCK-evoked activation. In sum, we here document a novel (patho)mechanism by which PVNOT signaling uncouples a gut-brain satiation pathway under obesogenic conditions.

neuroscience↗

bioRxiv2022

Hypercaloric diet triggers transient molecular rearrangements of astrocytes selectively in the arcuate nucleus

Hypothalamic astrocytes are particularly affected by energy-dense food consumption. How the anatomical location of these glial cells and their spatial molecular distribution in the arcuate nucleus of the hypothalamus (ARC) determine the cellular response to a high caloric diet remains unclear. In this study, we investigated their distinctive molecular responses following the exposure to a high-fat high-sugar (HFHS) diet, specifically in the ARC. Using RNA sequencing and proteomics, we showed that astrocytes have a distinct transcriptomic and proteomic profile dependent on their anatomical location, with a major proteomic reprogramming in hypothalamic astrocytes. By ARC single-cell sequencing, we observed that a HFHS diet dictates time- and cell-specific transcriptomic responses, revealing that astrocytes have the most distinct regulatory pattern compared to other cell types. Lastly, we topographically and molecularly characterized astrocytes expressing glial fibrillary acidic protein and/or aldehyde dehydrogenase 1 family member L1 in the ARC, of which the abundance was significantly increased, as well as the alteration in their spatial and molecular profiles, with a HFHS diet. Together, our results provide a detailed multi-omics view on the spatial and temporal changes of astrocytes particularly in the ARC during different time points of adaptation to a high caloric diet.

neuroscience↗

bioRxiv2022

Hypothalamic astrocyte control systemic glucose metabolism and energy balance via regulation of extra-synaptic glutamate signaling

The hypothalamus is key in the control of energy balance. However, to this day strategies targeting hypothalamic neurons failed to provide viable option to treat most metabolic diseases. Conversely, the role of astrocytes in systemic metabolic control has remained largely unexplored. Here we show that obesity promotes anatomically restricted remodeling of hypothalamic astrocyte activity. In the paraventricular nucleus (PVN) of the hypothalamus, chemogenetic manipulation of astrocytes results in bidirectional control of neighboring neuron activity, autonomic outflow, glucose metabolism and energy balance. Such process recruits a mechanism involving the astrocytic control of ambient glutamate levels, which becomes defective in obesity. Positive or negative chemogenetic manipulation of PVN astrocyte Ca2+ signals respectively worsen or improves metabolic status of diet-induced obese mice. Collectively, these findings highlight a yet unappreciated role for astrocyte in the direct control of systemic metabolism and suggest potential targets for anti-obesity strategy.

physiology↗

bioRxiv2021

The obesity-linked human lncRNA AATBC regulates adipocyte plasticity by stimulating mitochondrial dynamics and respiration

Adipocytes are critical regulators of metabolism and energy balance. While white adipocyte dysfunction is a hallmark of obesity-associated disorders, the activation of thermogenic brown and beige adipocytes is linked to improved cardiometabolic health. As adipocytes dynamically adapt to environmental cues by functionally switching between white and thermogenic phenotypes, a molecular understanding of this adipocyte plasticity could help improving energy balance and weight loss. Here, we show that the long non-coding RNA (lncRNA) Apoptosis associated transcript in bladder cancer (AATBC) is a human-specific regulator of adipocyte plasticity. Searching for new human lncRNAs implicated in adipocyte biology we compared transcriptional profiles of human adipose tissues and cultured adipocytes and discovered that AATBC was enriched in thermogenic conditions. Using primary human adipocytes and immortalized human adipocytes we found that gain-of-function of AATBC enhanced the thermogenic phenotype whereas loss-of-function diminished this effect. The AATBC-mediated increase in mitochondrial respiration was linked to a more fragmented mitochondrial network and vice versa. While we found that AATBC is predominantly located in the nucleus, its effect on global transcription was only marginal. As AATBC is specific to humans, we expressed AATBC in adipose tissue of mice to study its systemic impact, which led to lower plasma leptin levels. Interestingly, this association was also present in human subjects, as AATBC in adipose tissue was inversely correlated with plasma leptin levels, body mass index and other measures of metabolic health. In conclusion, AATBC is a novel obesity-linked regulator of adipocyte plasticity and mitochondrial function in humans.

molecular biology↗

bioRxiv2020

Identification and characterization of distinct murine brown adipocyte lineages

Brown adipose tissue (BAT) plays an important role in the regulation of body weight and glucose homeostasis. While increasing evidence supports white adipose tissue heterogeneity, little is known about heterogeneity within murine BAT. Using single cell RNA sequencing of the stromal vascular fraction of murine BAT and analysis of 67 brown preadipocyte and adipocyte clones we unravel heterogeneity within brown preadipocytes. Statistical analysis of gene expression profiles from these clones identifies markers distinguishing brown adipocyte lineages. We confirm the presence of distinct brown adipocyte populations in vivo using three identified markers; Eif5, Tcf25, and Bin1. Functionally, we demonstrate that loss of Bin1 enhances UCP1 expression and mitochondrial respiration, suggesting that Bin1 marks a dormant brown adipocyte type. The existence of multiple brown adipocyte lineages suggests distinct functional properties of BAT depending on its cellular composition, with potentially distinct function in thermogenesis and the regulation of whole body energy homeostasis.

cell biology↗

bioRxiv2020

Active integrins regulate white adipose tissue insulin sensitivity and brown fat thermogenesis

Reorganization of the extracellular matrix is a prerequisite for healthy adipose tissue expansion, whereas fibrosis is a key feature of adipose dysfunction and inflammation. However, very little is known about the direct effects of impaired cell-matrix interaction in adipocyte function and insulin sensitivity. Using adipose selective deletion of {beta}1 integrin (Itgb1adipo-cre) and Kindlin-2 (Kind2adipo-cre), we demonstrate here that active {beta}1 and {beta}3 integrins directly interact with the insulin receptor to regulate white adipocyte insulin action and systemic metabolism. Consequently, loss of adipose integrin activity, similar to loss of adipose insulin receptors, results in lipodystrophy and systemic insulin resistance. Conversely, we find that brown adipose tissue of Kind2adipo-cre and Itgb1adipo-cre mice is chronically hyperactivated, and has increased substrate delivery, reduced endothelial basement membrane thickness, and increased endothelial vesicular transport. Thus, we establish integrin-extracellular matrix interactions as key regulators of white and brown adipose tissue function and whole body metabolism.

physiology↗

bioRxiv2019

The Insulin Receptor In Astrocytes Is Involved In The Entrance Of Circulating Insulin Into The Brain

Circulating insulin enters into the brain through mechanisms that are not yet entirely understood. We now report that mice lacking insulin receptors (IR) in astrocytes show reduced uptake of circulating insulin and blunted brain responses to this circulating hormone, suggesting that astrocytes form part of the cellular pathway in the entrance of circulating insulin into the brain. Since we previously showed that ablation of IR in astrocytes decreases brain glucose uptake, we conclude that astrocytic IRs regulate uptake of circulating glucose and insulin.

neuroscience↗