scholarly journals Role of astroglia in diet-induced central neuroplasticity

2019 ◽  
Vol 121 (4) ◽  
pp. 1195-1206 ◽  
Author(s):  
Courtney Clyburn ◽  
Kirsteen N. Browning

Obesity, characterized by increased adiposity that develops when energy intake outweighs expenditure, is rapidly becoming a serious health crisis that affects millions of people worldwide and is associated with severe comorbid disorders including hypertension, cardiovascular disease, and type II diabetes. Obesity is also associated with the dysregulation of central neurocircuits involved in the control of autonomic, metabolic, and cognitive functions. Systemic inflammation associated with diet-induced obesity (DIO) has been proposed to be responsible for the development of these comorbidities as well as the dysregulation of central neurocircuits. A growing body of evidence suggests, however, that exposure to a high-fat diet (HFD) may cause neuroinflammation and astroglial activation even before systemic inflammation develops, which may be sufficient to cause dysregulation of central neurocircuits involved in energy homeostasis before the development of obesity. The purpose of this review is to summarize the current literature exploring astroglial-dependent modulation of central circuits following exposure to HFD and DIO, including not only dysregulation of neurocircuits involved in energy homeostasis and feeding behavior, but also the dysregulation of learning, memory, mood, and reward pathways.

2015 ◽  
Vol 309 (8) ◽  
pp. R835-R844 ◽  
Author(s):  
Emanuele Loro ◽  
Erin L. Seifert ◽  
Cynthia Moffat ◽  
Freddy Romero ◽  
Manoj K. Mishra ◽  
...  

IL-15Rα is the widely expressed primary binding partner for IL-15. Because of the wide distribution in nonlymphoid tissues like skeletal muscle, adipose, or liver, IL-15/IL-15Rα take part in physiological and metabolic processes not directly related to immunity. In fast muscle, lack of IL-15Rα promotes an oxidative switch, with increased mitochondrial biogenesis and fatigue resistance. These effects are predicted to reproduce some of the benefits of exercise and, therefore, improve energy homeostasis. However, the direct effects of IL-15Rα on metabolism and obesity are currently unknown. We report that mice lacking IL-15Rα (IL-15Rα−/−) are resistant to diet-induced obesity (DIO). High-fat diet-fed IL-15Rα−/− mice have less body and liver fat accumulation than controls. The leaner phenotype is associated with increased energy expenditure and enhanced fatty acid oxidation by muscle mitochondria. Despite being protected against DIO, IL-15Rα−/− are hyperglycemic and insulin-resistant. These findings identify novel roles for IL-15Rα in metabolism and obesity.


2020 ◽  
Vol 20 ◽  
pp. 100301
Author(s):  
Amit Goyal ◽  
Ankita Sharma ◽  
Deepika Sharma ◽  
Tapan Behl ◽  
Anjoo Kamboj ◽  
...  

2008 ◽  
Vol 295 (3) ◽  
pp. H1206-H1215 ◽  
Author(s):  
Cindy X. Fang ◽  
Feng Dong ◽  
D. Paul Thomas ◽  
Heng Ma ◽  
Leilei He ◽  
...  

Cellular hypertrophy is regulated by coordinated pro- and antigrowth machineries. Foxo transcription factors initiate an atrophy-related gene program to counter hypertrophic growth. This study was designed to evaluate the role of Akt, the forkhead transcription factor Foxo3a, and atrophy genes muscle-specific RING finger (MuRF)-1 and atrogin-1 in cardiac hypertrophy and contractile dysfunction associated with high-fat diet-induced obesity. Mice were fed a low- or high-fat diet for 6 mo along with a food-restricted high-fat weight control group. Echocardiography revealed decreased fractional shortening and increased end-systolic diameter and cardiac hypertrophy in high-fat obese but not in weight control mice. Cardiomyocytes from high-fat obese but not from weight control mice displayed contractile and intracellular Ca2+ defects including depressed maximal velocity of shortening/relengthening, prolonged duration of shortening/relengthening, and reduced intracellular Ca2+ rise and clearance. Caspase activities were greater in high-fat obese but not in weight control mouse hearts. Western blot analysis revealed enhanced basal Akt and Foxo3a phosphorylation and reduced insulin-stimulated phosphorylation of Akt and Foxo3a without changes in total protein expression of Akt and Foxo3a in high-fat obese hearts. RT-PCR and immunoblotting results displayed reduced levels of the atrogens atrogin-1 and MuRF-1, the upregulated hypertrophic markers GATA4 and ciliary neurotrophic factor receptor-α, as well as the unchanged calcineurin and proteasome ubiquitin in high-fat obese mouse hearts. Transfection of H9C2 myoblast cells with dominant-negative Foxo3a adenovirus mimicked palmitic acid (0.8 mM for 24 h)-induced GATA4 upregulation without an additive effect. Dominant-negative Foxo3a-induced upregulation of pAkt and repression of phosphatase and tensin homologue were abrogated by palmitic acid. These results suggest a cardiac hypertrophic response in high-fat diet-associated obesity at least in part through inactivation of Foxo3a by the Akt pathway.


2014 ◽  
Vol 89 (3) ◽  
pp. 399-412 ◽  
Author(s):  
Krisstonia Spruiell ◽  
Dominique Z. Jones ◽  
John M. Cullen ◽  
Emmanuel M. Awumey ◽  
Frank J. Gonzalez ◽  
...  

2018 ◽  
Vol 32 (S1) ◽  
Author(s):  
Aneesh Singal ◽  
Caitlin R. Coker ◽  
Sarah S. Bingaman ◽  
Amy C. Arnold ◽  
Yuval Silberman

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Doyeon Kim ◽  
Yuna Lee ◽  
Hyeung-Rak Kim ◽  
Yeo Jin Park ◽  
Hongik Hwang ◽  
...  

AbstractSargassum serratifolium (C. Agardh) C.Agardh, a marine brown alga, has been consumed as a food and traditional medicine in Asia. A previous study showed that the meroterpenoid-rich fraction of an ethanolic extract of S. serratifolium (MES) induced adipose tissue browning and suppressed diet-induced obesity and metabolic syndrome when orally supplemented. Sargahydroquinoic acid (SHQA) is a major component of MES. However, it is unclear whether SHQA regulates energy homeostasis through the central nervous system. To examine this, SHQA was administrated through the third ventricle in the hypothalamus in high-fat diet-fed C57BL/6 mice and investigated its effects on energy homeostasis. Chronic administration of SHQA into the brain reduced body weight without a change in food intake and improved metabolic syndrome-related phenotypes. Cold experiments and biochemical analyses indicated that SHQA elevated thermogenic signaling pathways, as evidenced by an increase in body temperature and UCP1 signaling in white and brown adipose tissues. Peripheral denervation experiments using 6-OHDA indicated that the SHQA-induced anti-obesity effect is mediated by the activation of the sympathetic nervous system, possibly by regulating genes associated with sympathetic outflow and GABA signaling pathways. In conclusion, hypothalamic injection of SHQA elevates peripheral thermogenic signaling and ameliorates diet-induced obesity.


2020 ◽  
Vol 34 (3) ◽  
Author(s):  
Rasha Abdelmawla Ghazala ◽  
Azza El Medney ◽  
Anisa Meleis ◽  
Passant Mohie El dien ◽  
Hend Samir

2020 ◽  
Vol 79 (OCE2) ◽  
Author(s):  
Matteo Fornai ◽  
Carolina Pellegrini ◽  
Vanessa D'Antongiovanni ◽  
Laura Benvenuti ◽  
Nunzia Bernardini ◽  
...  

AbstractIntroductionEnteric glial cells (EGCs) contribute to the regulation of bowel motility, and have been implicated in the onset and development of several digestive disorders. However, the involvement of EGCs in obesity-related intestinal dysmotility is unknown. Accordingly, this study examined the role of EGCs in colonic neuromuscular dysfunctions in a mouse model of diet-induced obesity.Materials and MethodsC57BL/6 male mice (n = 6 per group) were fed with standard diet (SD) or high fat diet (HFD) for 8 weeks. Body and epididymal fat weight, and blood fasting glucose levels were evaluated the day before sacrifice. Colonic longitudinal muscle strips were set up in organ baths with Krebs solution and connected to isometric transducers. The effects of fluorocitrate (FC, gliotoxin) were tested on contractile responses mediated by NK1 tachykininergic receptors upon application of electrical stimuli (0.5 ms, 28 V, 10 Hz) [incubation with atropine, guanethidine, L-NAME, GR159897 and SB218795 (NK2 and NK3 antagonists, respectively)] or exogenous substance P (SP). Colonic levels of interleukin (IL)-1β, IL-6, malondialdehyde (MDA) and occludin (a tight junction protein involved the maintenance of mucosal barrier) were measured. Cultured rat EGCs were exposed to palmitate and lipopolysaccharide (LPS), either alone or in combination, to mimic the exposure to HFD. IL-1β and SP levels were then assessed in cell supernatants, while toll-like receptor 4 (TLR4) expression was evaluated in cell lysates.ResultsHFD-mice displayed increments of body weight, epididymal fat weight and blood glucose levels. In in vitro experiments, electrically induced colonic tachykininergic contractions were enhanced in HFD mice, as compared with SD animals. No differences were observed when comparing contractions to exogenous SP. The increase in electrically evoked tachykininergic contractions was blunted upon incubation with the gliotoxin FC. Exogenous SP-induced contractions were not affected by FC. HFD mice displayed an increase in colonic IL-1β, IL-6 and MDA levels and a reduced occludin expression, as compared with SD mice. Exposure of EGCs to palmitate, alone or in combination with LPS, resulted in a significant increase in TLR4 expression, while LPS alone was without effects. The combination of palmitate and LPS increased significantly IL-1β and SP levels in cell supernatants, while single treatments were without effects.DiscussionHFD is characterized by colonic dysmotility along with bowel inflammation, oxidative stress, and an impairment of mucosal barrier integrity. In this setting, the hyperactivation of EGCs, likely via TLR4, appears to contribute to inflammation and colonic tachykininergic motor dysfunctions.


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