Acute psychological stress has long been known to decrease host fitness to inflammation in a wide variety of diseases, but how this occurs is incompletely understood. Using mouse models, we show that ...interleukin-6 (IL-6) is the dominant cytokine inducible upon acute stress alone. Stress-inducible IL-6 is produced from brown adipocytes in a beta-3-adrenergic-receptor-dependent fashion. During stress, endocrine IL-6 is the required instructive signal for mediating hyperglycemia through hepatic gluconeogenesis, which is necessary for anticipating and fueling “fight or flight” responses. This adaptation comes at the cost of enhancing mortality to a subsequent inflammatory challenge. These findings provide a mechanistic understanding of the ontogeny and adaptive purpose of IL-6 as a bona fide stress hormone coordinating systemic immunometabolic reprogramming. This brain-brown fat-liver axis might provide new insights into brown adipose tissue as a stress-responsive endocrine organ and mechanistic insight into targeting this axis in the treatment of inflammatory and neuropsychiatric diseases.
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•IL-6 is the dominant endocrine cytokine induced by acute stress in mice•Stress-inducible IL-6 is produced in brown adipocytes via ADRB3 signaling•IL-6 is required for stress hyperglycemia and adaptive “fight or flight” responses•Stress-induced IL-6 decreases tolerance to a subsequent inflammatory challenge
During acute psychological stress, brown adipocytes initiate a chain of events mediated by adrenergic signaling and IL-6 release that metabolically fuels “fight or flight” adaptive responses but at the same time comes at an inflammatory cost.
Metabolic scaling, the inverse correlation of metabolic rates to body mass, has been appreciated for more than 80 years. Studies of metabolic scaling have largely been restricted to mathematical ...modeling of caloric intake and oxygen consumption, and mostly rely on computational modeling. The possibility that other metabolic processes scale with body size has not been comprehensively studied. To address this gap in knowledge, we employed a systems approach including transcriptomics, proteomics, and measurement of in vitro and in vivo metabolic fluxes. Gene expression in livers of five species spanning a 30,000-fold range in mass revealed differential expression according to body mass of genes related to cytosolic and mitochondrial metabolic processes, and to detoxication of oxidative damage. To determine whether flux through key metabolic pathways is ordered inversely to body size, we applied stable isotope tracer methodology to study multiple cellular compartments, tissues, and species. Comparing C57BL/6 J mice with Sprague-Dawley rats, we demonstrate that while ordering of metabolic fluxes is not observed in in vitro cell-autonomous settings, it is present in liver slices and in vivo. Together, these data reveal that metabolic scaling extends beyond oxygen consumption to other aspects of metabolism, and is regulated at the level of gene and protein expression, enzyme activity, and substrate supply.
Introduction: The Science of Stress Ramanathan, Renuka; Desrouleaux, Reina
The Yale journal of biology & medicine,
03/2022, Letnik:
95, Številka:
1
Journal Article
Recenzirano
Odprti dostop
...in addition to the direct biological consequences of SARS-CoV2 infection on the brain, chronic stress associated with the COVID-19 pandemic impacts similar neuronal signaling pathways in the CNS ...and PNS that hamper normal physiological function. Davis et al. examine how increased reactive oxygen species in the embryonic brain generated due to prenatal stress affect the morphology and activity of neuronal cells during development and in mature brains. Available from:https://www.apa.org/news/press/releases/stress/2020/report-october World Health Organization. .2013..Who releases guidance on mental health care after trauma..
Nonalcoholic fatty liver disease (NAFLD) is a global metabolic disease that comprises a broad spectrum of liver dysfunction ranging from nonalcoholic fatty liver (NAFL) to nonalcoholic ...steatohepatitis (NASH) with fibrosis. It is largely unknown how the communication between hepatocytes and non-parenchymal cells dictates the disease progression from NAFL to NASH and fibrosis. Dysregulation of protein O-GlcNAcylation in hepatocytes has been implicated in a wide range of liver diseases. In this study, we demonstrate the role of O‑GlcNAc transferase (OGT) in mediating intercellular crosstalk between hepatocytes and immune cells in NASH-fibrosis development. RNA-sequencing analysis of wildtype and hepatocyte-specific OGT knockout mice was performed and trefoil factor 2 (TFF2) was identified as one of the highly induced genes encoding secreted proteins in OGT-deficient hepatocytes. Immunohistochemistry and western blot were performed to reveal decreased OGT and increased TFF2 expression in the liver of NAFLD patients. Mechanically, OGT was found to repress TFF2 transcription in hepatocytes by modifying forkhead box protein A2 (FOXA2). Recombinant TFF2 along with NASH stimuli was applied to a 3D spheroid culture system comprised of hepatocytes and non-parenchymal cells and TFF2 was shown to promote NASH stimuli-induced triglyceride secretion and elevate the expression of pro-inflammatory and fibrogenic genes. ELISA and RT-qPCR were performed to further show that TFF2 treatment induced the expression of Th1-type cytokines (IFN-γ and TNF-α) and Th17-type cytokine (IL17) in CD4 T cells, promoting Th1 and Th17 differentiation. Collectively, these results identify an OGT-TFF2 axis that mediates the crosstalk between hepatocytes and CD4 T cells during NASH pathogenesis, revealing a potential therapeutic target for the treatment of chronic liver disease.
Disclosure
L. Zhang: None. Q. Wang: None. R. Desrouleaux: None. X. Yang: None.
Funding
American Diabetes Association (1-19-IBS-119 to X.Y.); National Institutes of Health (R01DK089098, P30DK34989)
Abstract
O-linked N-acetyl-glucosamine glycosylation (O-GlcNAcylation) of intracellular proteins is a dynamic process broadly implicated in age-related disease, yet it remains uncharacterized whether ...and how O-GlcNAcylation contributes to the natural aging process. O-GlcNAc transferase (OGT) and the opposing enzyme O-GlcNAcase (OGA) control this nutrient-sensing protein modification in cells. Here, we show that global O-GlcNAc levels are increased in multiple tissues of aged mice. In aged liver, carbamoyl phosphate synthetase 1 (CPS1) is among the most heavily O-GlcNAcylated proteins. CPS1 O-GlcNAcylation is reversed by calorie restriction and is sensitive to genetic and pharmacological manipulations of the O-GlcNAc pathway. High glucose stimulates CPS1 O-GlcNAcylation and inhibits CPS1 activity. Liver-specific deletion of OGT potentiates CPS1 activity and renders CPS1 irresponsive to further stimulation by a prolonged fasting. Our results identify CPS1 O-GlcNAcylation as a key nutrient-sensing regulatory step in the urea cycle during aging and dietary restriction, implying a role for mitochondrial O-GlcNAcylation in nutritional regulation of longevity.
Sickness behaviors, including anorexia, are evolutionarily conserved responses to acute infections. Inflammation-induced anorexia causes dramatic metabolic changes, of which components critical to ...survival are unique depending on the type of inflammation. Glucose supplementation during the anorectic period induced by bacterial inflammation suppresses adaptive fasting metabolic pathways, including fibroblast growth factor 21 (FGF21), and decreases survival. Consistent with this observation, FGF21-deficient mice are more susceptible to mortality from endotoxemia and polybacterial peritonitis. Here, we report that increased circulating FGF21 during bacterial inflammation is hepatic derived and required for survival through the maintenance of thermogenesis, energy expenditure, and cardiac function. FGF21 signaling downstream of its obligate coreceptor, β-Klotho (KLB), is required in bacterial sepsis. However, FGF21 modulates thermogenesis and chronotropy independent of the adipose, forebrain, and hypothalamus, which are operative in cold adaptation, suggesting that in bacterial inflammation, either FGF21 signals through a novel, undescribed target tissue or concurrent signaling of multiple KLB-expressing tissues is required.
Acute psychological stress has long been known to decrease host fitness
to inflammation in a wide variety of diseases, but how this occurs is
incompletely understood. Using mouse models, we show that ...IL6 is the dominant
cytokine inducible upon acute stress alone. Stress-inducible IL6 is produced
from brown adipocytes in a beta-3-adrenergic-receptor-dependent fashion. During
stress, endocrine IL6 is the required instructive signal for mediating
hyperglycemia through hepatic gluconeogenesis, which is necessary for
anticipating and fueling “fight or flight” responses. This
adaptation came at the cost of enhancing mortality to a subsequent inflammatory
challenge. These findings provide a mechanistic understanding of the ontogeny
and adaptive purpose of IL6 as a
bona fide
stress hormone
coordinating systemic immunometabolic reprogramming. This brain-brown fat-liver
axis may provide new insights into brown adipose tissue as a stress-responsive
endocrine organ and mechanistic insight into targeting this axis in the
treatment of inflammatory and neuropsychiatric diseases.
During acute psychological stress, brown adipocytes initiate a chain of
events mediated by adrenergic signaling and IL6 release that metabolically fuels
“fight or flight” adaptive responses but at the same time comes at
an inflammatory cost.
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