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Sabatini, P. V.

Publications and source records attributed to Sabatini, P. V..

6 recordsLinked to original sources

A Cross-Species Atlas of the Dorsal Vagal Complex Reveals Neural Mediators of Cagrilintide's Effects on Energy Balance

Amylin analogs, including potential anti-obesity therapies like cagrilintide, act on neurons in the brainstem dorsal vagal complex (DVC) that express calcitonin receptors (CALCR). These receptors, often combined with receptor activity-modifying proteins (RAMPs), mediate the suppression of food intake and body weight. To understand the molecular and neural mechanisms of cagrilintide action, we used single-nucleus RNA sequencing to define 89 cell populations across the rat, mouse, and non-human primate caudal brainstem. We then integrated spatial profiling to reveal neuron distribution in the rat DVC. Furthermore, we compared the acute and long-term transcriptional responses to cagrilintide across DVC neurons of rats, which exhibit strong cagrilintide responsiveness, and mice, which respond poorly to cagrilintide over the long term. We found that cagrilintide promoted long-term transcriptional changes, including increased prolactin releasing hormone (Prlh) expression, in the nucleus of the solitary tract (NTS) Calcr/Prlh cells in rats, but not in mice, suggesting the importance of NTS Calcr/Prlh cells for sustained weight loss. Indeed, activating rat area postrema Calcr cells briefly reduced food intake but failed to decrease food intake or body weight over the long term. Overall, these results not only provide a cross-species and spatial atlas of DVC cell populations but also define the molecular and neural mediators of acute and long-term cagrilintide action.

bioinformatics↗

A unified rodent atlas reveals the cellular complexity and evolutionary divergence of the dorsal vagal complex

The dorsal vagal complex (DVC) is a region in the brainstem comprised of an intricate network of specialized cells responsible for sensing and propagating many appetite-related cues. Understanding the dynamics controlling appetite requires deeply exploring the cell types and transitory states harbored in this brain site. We generated a multi-species DVC cell atlas using single nuclei RNAseq (sn-RNAseq), by curating and harmonizing mouse and rat data, which includes >180,000 cells and 123 cell identities at 5 granularities of cellular resolution. We report unique DVC features such as Kcnj3 expression in Ca+-permeable astrocytes as well as new cell populations like neurons co-expressing Th and Cck, and a leptin receptor-expressing neuron population in the rat area postrema which is marked by expression of the progenitor marker, Pdgfra. In summary, our findings demonstrate a high degree of complexity within the DVC and provide a valuable tool for the study of this metabolic center.

neuroscience↗

GDNF family receptor alpha-like (GFRAL) expression is restricted to the caudal brainstem

The TGF-{beta} cytokine, growth differentiation factor 15 (GDF15) is a critical mediator of the physiologic response to a range of cellular stresses. While circulating levels of GDF15 are normally very low, these levels increase substantially under a number of acute and chronic pathogenic states including mycotoxin exposure, infection and cancer. GDF15 controls a range of physiologic outputs including reduced appetite, gastric motility, hyperalgesia, emesis, energy expenditure and immune cell function via the GDNF family receptor alpha-like (GFRAL). While the area postrema and nucleus of the solitary tract (AP/NTS) within the caudal brainstem are the only known sites of Gfral-expressing cells, Gfral may also be expressed in other cell types. We therefore utilized single molecule in-situ hybridizations and genetic mouse models to label Gfral-expressing cells from development to adult mouse. With both approaches, we found Gfral-labelled cells in the brainstem and extremely rare Gfral-labelled cells in peripheral tissues in the mouse under normal physiological conditions. Confirming these findings, single nucleus RNA-sequencing of human tissues demonstrated nearly undetectable levels of Gfral mRNA in sites outside the AP/NTS. Our findings confirm AP/NTS neurons are the major site of Gfral expression.

molecular biology↗

The neurons that drive infradian sleep-wake and mania-like behavioral rhythms

Infradian mood and sleep-wake rhythms with periods of 48 hr and beyond have been observed in bipolar disorder (BD) subjects that even persist in time isolation, indicating an endogenous origin. Here we show that mice exposed to methamphetamine (Meth) in drinking water develop infradian locomotor rhythms with periods of 48 hr and beyond which extend to sleep length and mania-like behaviors in support of a model for cycling in BD. This cycling capacity is abrogated upon genetic disruption of DA production in DA neurons of the ventral tegmental area (VTA) or ablation of nucleus accumbens (NAc) projecting, dopamine (DA) neurons. Chemogenetic activation of NAc-projecting DA neurons leads to locomotor period lengthening in clock deficient mice, while cytosolic calcium in DA processes of the NAc was found fluctuating synchronously with locomotor behavior. Together, our findings argue that BD cycling relies on infradian rhythm generation that depends on NAc-projecting DA neurons.

neuroscience↗

Cross-Species Analysis Defines the Conservation of Anatomically-Segregated VMH Neuron Populations

The ventromedial hypothalamic nucleus (VMH) controls diverse behaviors and physiologic functions, suggesting the existence of multiple VMH neural subtypes with distinct functions. Combing Translating Ribosome Affinity Purification with RNA sequencing (TRAP-seq) data with snRNA-seq data, we identified 24 mouse VMH neuron clusters. Further analysis, including snRNA-seq data from macaque tissue, defined a more tractable VMH parceling scheme consisting of 6 major genetically- and anatomically-differentiated VMH neuron classes with good cross-species conservation. In addition to two major ventrolateral classes, we identified three distinct classes of dorsomedial VMH neurons. Consistent with previously-suggested unique roles for leptin receptor (Lepr)-expressing VMH neurons, Lepr expression marked a single dorsomedial class. We also identified a class of glutamatergic VMH neurons that resides in the tuberal region, anterolateral to the neuroanatomical core of the VMH. This atlas of conserved VMH neuron populations provides an unbiased starting point for the analysis of VMH circuitry and function.

neuroscience↗

Gfral-expressing Neurons Suppress Food Intake via Aversive Pathways

To determine the function and mechanisms of action for hindbrain neurons that express GFRAL, the receptor for the anorexigenic peptide, GDF-15, we generated Gfralcre and conditional GfralCreERT mice. While signals of infection or pathophysiologic states (rather than meal ingestion) stimulate GFRAL neurons, the artificial activation of GfralCre- expressing neurons inhibited feeding, decreased gastric emptying, and promoted a conditioned taste aversion (CTA). Additionally, activation of the smaller population of GFRAL neurons captured by the GfralCreERT allele decreased gastric emptying and produced a CTA without suppressing food intake, suggesting that GFRAL neurons primarily modulate gastric physiology and stimulate aversive responses. GFRAL neurons most strongly innervated the parabrachial nucleus (PBN), where they targeted CGRP-expressing (CGRPPBN) neurons. Silencing CGRPPBN neurons abrogated the aversive and anorexic effects of GDF-15. These findings suggest that GFRAL neurons link non-meal-associated, pathophysiologic signals to the aversive suppression of nutrient uptake and absorption.

neuroscience↗