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Hypothalamic AgRP neurons exert top-down control on systemic TNF-α release during endotoxemia

Boutagouga Boudjadja, Mehdi ; Culotta, Isabella ; de Paula, Gabriela C. LU ; Harno, Erika ; Hunter, Jenna ; Cavalcanti-de-Albuquerque, João Paulo ; Luckman, Simon M. ; Hepworth, Matthew ; White, Anne and Aviello, Gabriella , et al. (2022) In Current Biology 32(21). p.4-4706
Abstract
Loss of appetite and negative energy balance are common features of endotoxemia in all animals and are thought to have protective roles by reducing nutrient availability to host and pathogen metabolism. Accordingly, fasting and caloric restriction have well-established anti-inflammatory properties. However, in response to reduced nutrient availability at the cellular and organ levels, negative energy balance also recruits distinct energy-sensing brain circuits, but it is not known whether these neuronal systems have a role in its anti-inflammatory effects. Here, we report that hypothalamic AgRP neurons—a critical neuronal population for the central representation of negative energy balance—have parallel immunoregulatory functions. We found... (More)
Loss of appetite and negative energy balance are common features of endotoxemia in all animals and are thought to have protective roles by reducing nutrient availability to host and pathogen metabolism. Accordingly, fasting and caloric restriction have well-established anti-inflammatory properties. However, in response to reduced nutrient availability at the cellular and organ levels, negative energy balance also recruits distinct energy-sensing brain circuits, but it is not known whether these neuronal systems have a role in its anti-inflammatory effects. Here, we report that hypothalamic AgRP neurons—a critical neuronal population for the central representation of negative energy balance—have parallel immunoregulatory functions. We found that when endotoxemia occurs in fasted mice, the activity of AgRP neurons remains sustained, but this activity does not influence feeding behavior and endotoxemic anorexia. Furthermore, we found that endotoxemia acutely desensitizes AgRP neurons, which also become refractory to inhibitory signals. Mimicking this sustained AgRP neuron activity in fed mice by chemogenetic activation—a manipulation known to recapitulate core behavioral features of fasting—results in reduced acute tumor necrosis factor alpha (TNF-α) release during endotoxemia. Mechanistically, we found that endogenous glucocorticoids play an important role: glucocorticoid receptor deletion from AgRP neurons prevents their endotoxemia-induced desensitization, and importantly, it counteracts the fasting-induced suppression of TNF-α release, resulting in prolonged sickness. Together, these findings provide evidence directly linking AgRP neuron activity to the acute response during endotoxemia, suggesting that these neurons are a functional component of the immunoregulatory effects associated with negative energy balance and catabolic metabolism. (Less)
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publishing date
type
Contribution to journal
publication status
published
subject
keywords
hypothalamus, energy balance, inflammation, sickness behavior, fasting, glucocorticoids, arcuate nucleus, NPY, appetite
in
Current Biology
volume
32
issue
21
pages
13 pages
publisher
Elsevier
external identifiers
  • pmid:36182699
  • scopus:85141235906
ISSN
1879-0445
DOI
10.1016/j.cub.2022.09.017
language
English
LU publication?
no
id
975e21dc-e072-47d7-a3d0-857fccaddb51
date added to LUP
2022-10-17 15:23:07
date last changed
2023-10-26 15:00:42
@article{975e21dc-e072-47d7-a3d0-857fccaddb51,
  abstract     = {{Loss of appetite and negative energy balance are common features of endotoxemia in all animals and are thought to have protective roles by reducing nutrient availability to host and pathogen metabolism. Accordingly, fasting and caloric restriction have well-established anti-inflammatory properties. However, in response to reduced nutrient availability at the cellular and organ levels, negative energy balance also recruits distinct energy-sensing brain circuits, but it is not known whether these neuronal systems have a role in its anti-inflammatory effects. Here, we report that hypothalamic AgRP neurons—a critical neuronal population for the central representation of negative energy balance—have parallel immunoregulatory functions. We found that when endotoxemia occurs in fasted mice, the activity of AgRP neurons remains sustained, but this activity does not influence feeding behavior and endotoxemic anorexia. Furthermore, we found that endotoxemia acutely desensitizes AgRP neurons, which also become refractory to inhibitory signals. Mimicking this sustained AgRP neuron activity in fed mice by chemogenetic activation—a manipulation known to recapitulate core behavioral features of fasting—results in reduced acute tumor necrosis factor alpha (TNF-α) release during endotoxemia. Mechanistically, we found that endogenous glucocorticoids play an important role: glucocorticoid receptor deletion from AgRP neurons prevents their endotoxemia-induced desensitization, and importantly, it counteracts the fasting-induced suppression of TNF-α release, resulting in prolonged sickness. Together, these findings provide evidence directly linking AgRP neuron activity to the acute response during endotoxemia, suggesting that these neurons are a functional component of the immunoregulatory effects associated with negative energy balance and catabolic metabolism.}},
  author       = {{Boutagouga Boudjadja, Mehdi and Culotta, Isabella and de Paula, Gabriela C. and Harno, Erika and Hunter, Jenna and Cavalcanti-de-Albuquerque, João Paulo and Luckman, Simon M. and Hepworth, Matthew and White, Anne and Aviello, Gabriella and D’Agostino, Giuseppe}},
  issn         = {{1879-0445}},
  keywords     = {{hypothalamus; energy balance; inflammation; sickness behavior; fasting; glucocorticoids; arcuate nucleus; NPY; appetite}},
  language     = {{eng}},
  month        = {{09}},
  number       = {{21}},
  pages        = {{4--4706}},
  publisher    = {{Elsevier}},
  series       = {{Current Biology}},
  title        = {{Hypothalamic AgRP neurons exert top-down control on systemic TNF-α release during endotoxemia}},
  url          = {{http://dx.doi.org/10.1016/j.cub.2022.09.017}},
  doi          = {{10.1016/j.cub.2022.09.017}},
  volume       = {{32}},
  year         = {{2022}},
}