scholarly journals Recent advances in understanding the role of leptin in energy homeostasis

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 451
Author(s):  
Heike Münzberg ◽  
Prachi Singh ◽  
Steven B. Heymsfield ◽  
Sangho Yu ◽  
Christopher D. Morrison
Keyword(s):  
Food Intake ◽  
Energy Expenditure ◽  
Energy Homeostasis ◽  
Critical Role ◽  
Early Data ◽  
Dynamic Changes ◽  
Leptin Signaling ◽  
Future Studies ◽  
Physiological Adaptations

The hormone leptin plays a critical role in energy homeostasis, although our overall understanding of acutely changing leptin levels still needs improvement. Several developments allow a fresh look at recent and early data on leptin action. This review highlights select recent publications that are relevant for understanding the role played by dynamic changes in circulating leptin levels. We further discuss the relevance for our current understanding of leptin signaling in central neuronal feeding and energy expenditure circuits and highlight cohesive and discrepant findings that need to be addressed in future studies to understand how leptin couples with physiological adaptations of food intake and energy expenditure.

scholarly journals The central melanocortin system and human obesity

2020 ◽  
Author(s):  
Yongjie Yang ◽  
Yong Xu
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Energy Expenditure ◽  
Genetic Variants ◽  
Energy Homeostasis ◽  
Critical Role ◽  
Human Obesity ◽  
Melanocortin System ◽  
Prevalence Of Obesity

Abstract The prevalence of obesity and the associated comorbidities highlight the importance of understanding the regulation of energy homeostasis. The central melanocortin system plays a critical role in controlling body weight balance. Melanocortin neurons sense and integrate the neuronal and hormonal signals, and then send regulatory projections, releasing anorexigenic or orexigenic melanocortin neuropeptides, to downstream neurons to regulate the food intake and energy expenditure. This review summarizes the latest progress in our understanding of the role of the melanocortin pathway in energy homeostasis. We also review the advances in the identification of human genetic variants that cause obesity via mechanisms that affect the central melanocortin system, which have provided rational targets for treatment of genetically susceptible patients.

scholarly journals STAT3 but Not ERK2 Is a Crucial Mediator Against Diet-Induced Obesity via VMH Neurons

2021 ◽  
Author(s):  
Gabriel Henrique Marques Gonçalves ◽  
Sabrina Mara Tristão ◽  
Rafaella Eduarda Volpi ◽  
Gislaine Almeida-Pereira ◽  
Beatriz de Carvalho Borges ◽  
...  
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Energy Expenditure ◽  
Energy Homeostasis ◽  
Specific Pattern ◽  
Conditional Knockout ◽  
Steroidogenic Factor 1 ◽  
Diet Induced Obesity ◽  
Affect Body Weight

Leptin plays an important role in the protection against diet-induced obesity (DIO) by its actions in ventromedial hypothalamic (VMH) neurons. However, little is known about the intracellular mechanisms involved in these effects. To assess the role of the STAT3 and ERK2 signaling in neurons that express the steroidogenic factor 1 (SF1) in the VMH on energy homeostasis, we used cre-lox technology to generate male and female mice with specific disruption of STAT3 or ERK2 in SF1 neurons of the VMH. We demonstrated that the conditional knockout of STAT3 in SF1 neurons of the VMH did not affect body weight, food intake, energy expenditure and glucose homeostasis in animals on regular chow. However, when challenged with high-fat diet (HFD), loss of STAT3 in SF1 neurons caused a significant increase in body weight, food intake and energy efficiency that was more remarkable in females which also showed a decrease in energy expenditure. In contrast, deletion of ERK2 in SF1 neurons of VMH did not have any impact on energy homeostasis in both regular diet and HFD conditions. In conclusion, STAT3 but not ERK2 signaling in SF1 neurons of VMH plays a crucial role to protect against DIO in a sex-specific pattern.

scholarly journals Turn it off and on again: characteristics and control of torpor

2021 ◽  
Vol 6 ◽  
pp. 313
Author(s):  
Michael Ambler ◽  
Timna Hitrec ◽  
Anthony Pickering
Keyword(s):  
Food Intake ◽  
Energy Expenditure ◽  
Current Understanding ◽  
Critical View ◽  
Future Studies ◽  
Wide Range ◽  
Physiological Adaptations ◽  
Hypometabolic State ◽  
And Control ◽  
Environmental Challenge

Torpor is a hypothermic, hypoactive, hypometabolic state entered into by a wide range of animals in response to environmental challenge. This review summarises the current understanding of torpor. We start by describing the characteristics of the wide-ranging physiological adaptations associated with torpor. Next follows a discussion of thermoregulation, control of food intake and energy expenditure, and the interactions of sleep and thermoregulation, with particular emphasis on how those processes pertain to torpor. We move on to take a critical view of the evidence for the systems that control torpor entry, including both the efferent circulating factors that signal the need for torpor, and the central processes that orchestrate it. Finally, we consider how the putative circuits responsible for torpor induction integrate with the established understanding of thermoregulation under non-torpid conditions and highlight important areas of uncertainty for future studies.

scholarly journals STAT3 but Not ERK2 Is a Crucial Mediator Against Diet-Induced Obesity via VMH Neurons

2021 ◽  
Author(s):  
Gabriel Henrique Marques Gonçalves ◽  
Sabrina Mara Tristão ◽  
Rafaella Eduarda Volpi ◽  
Gislaine Almeida-Pereira ◽  
Beatriz de Carvalho Borges ◽  
...  
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Energy Expenditure ◽  
Energy Homeostasis ◽  
Specific Pattern ◽  
Conditional Knockout ◽  
Steroidogenic Factor 1 ◽  
Diet Induced Obesity ◽  
Affect Body Weight

Leptin plays an important role in the protection against diet-induced obesity (DIO) by its actions in ventromedial hypothalamic (VMH) neurons. However, little is known about the intracellular mechanisms involved in these effects. To assess the role of the STAT3 and ERK2 signaling in neurons that express the steroidogenic factor 1 (SF1) in the VMH on energy homeostasis, we used cre-lox technology to generate male and female mice with specific disruption of STAT3 or ERK2 in SF1 neurons of the VMH. We demonstrated that the conditional knockout of STAT3 in SF1 neurons of the VMH did not affect body weight, food intake, energy expenditure and glucose homeostasis in animals on regular chow. However, when challenged with high-fat diet (HFD), loss of STAT3 in SF1 neurons caused a significant increase in body weight, food intake and energy efficiency that was more remarkable in females which also showed a decrease in energy expenditure. In contrast, deletion of ERK2 in SF1 neurons of VMH did not have any impact on energy homeostasis in both regular diet and HFD conditions. In conclusion, STAT3 but not ERK2 signaling in SF1 neurons of VMH plays a crucial role to protect against DIO in a sex-specific pattern.

scholarly journals PSYCHOGEOGRAPHICAL EXPERIENCE BETWEEN THE SELF AND THE PLACE

2022 ◽  
Vol 7 (1) ◽  
pp. 243-263
Author(s):  
Mohd Fadhli Shah Khaidzir ◽  
Ruzy Suliza Hashim ◽  
Noraini Md. Yusof
Keyword(s):  
Critical Role ◽  
Critical Factor ◽  
The Self ◽  
Future Research ◽  
Future Studies ◽  
Place Meaning ◽  
Solid Foundation ◽  
Self Discovery ◽  
Attachment Place

Background and Purpose: The absence of psychogeographical awareness is a critical factor contributing to the lackadaisical attitudes towards the place and its environment. As a result, it enables an individual to fully experience a location, both physically and intellectually, while also gaining a feeling of self-discovery and self-realisation.   Methodology: The purpose of this study was to examine the responses of a group of individuals who participated in a field observation. 40 participants from a Malaysian university's foundation level were brought to Malacca to experience the environment's geographical scenery at their own leisure. The survey data was then manually transcribed and analysed in accordance with the study's aim.   Findings: Interactions with individuals and observation of features in the countryside and urban surroundings enabled participants to go on a psychogeographical journey that influenced their way of thinking and behaving. All participants felt that the journey had influenced their experiences and perspectives on their thinking and behaviour, highlighting the critical role of this notion in establishing the connection between place and self.   Contributions:  The findings of this study provide a solid foundation for future research in the field of psychogeography. The data may be used as a baseline for future studies to determine whether a comparable impact exists in other locations, with or without significant features like those found in Malacca.   Keywords: Psychogeography, place attachment, place meaning, self-discovery, Malacca.   Cite as: Khaidzir, M. F. S., Hashim, R. S., & Md. Yusof, N. (2022). Psychogeographical experience between the self and the place.  Journal of Nusantara Studies, 7(1), 243-263. http://dx.doi.org/10.24200/jonus.vol7iss1pp243-263

scholarly journals The essential role of sodium bioenergetics and ATP homeostasis in the developmental transitions of a cyanobacterium

2020 ◽  
Author(s):  
Sofia Doello ◽  
Markus Burkhardt ◽  
Karl Forchhammer
Keyword(s):  
Energy Homeostasis ◽  
Nitrogen Starvation ◽  
Critical Role ◽  
Quiescent State ◽  
Bacterial Survival ◽  
Bacterial Populations ◽  
Photoautotrophic Growth ◽  
Available Energy ◽  
Atp Levels

The ability to resume growth after a dormant period is an important strategy for the survival and spreading of bacterial populations. Energy homeostasis is critical in the transition into and out of a quiescent state. Synechocystis sp. PCC 6803, a non-diazotrophic cyanobacterium, enters metabolic dormancy as a response to nitrogen starvation. We used Synechocystis as a model to investigate the regulation of ATP homeostasis during dormancy and unraveled a critical role for sodium bioenergetics in dormant cells. During nitrogen starvation, cells reduce their ATP levels and engage sodium bioenergetics to maintain the minimum ATP content required for viability. When nitrogen becomes available, energy requirements rise, and cells immediately increase ATP levels employing sodium bioenergetics and glycogen catabolism. These processes allow them to restore the photosynthetic machinery and resume photoautotrophic growth. Our work reveals a precise regulation of the energy metabolism essential for bacterial survival during periods of nutrient deprivation.

scholarly journals Evidence for hypothalamic ketone body sensing: impact on food intake and peripheral metabolic responses in mice

2016 ◽  
Vol 310 (2) ◽  
pp. E103-E115 ◽  
Author(s):  
Lionel Carneiro ◽  
Sarah Geller ◽  
Xavier Fioramonti ◽  
Audrey Hébert ◽  
Cendrine Repond ◽  
...  
Keyword(s):  
Food Intake ◽  
Ketone Body ◽  
Energy Homeostasis ◽  
Ketone Bodies ◽  
Glucose Production ◽  
Body Level ◽  
Homeostasis Regulation ◽  
The Impact ◽  
Body Concentration

Monocarboxylates have been implicated in the control of energy homeostasis. Among them, the putative role of ketone bodies produced notably during high-fat diet (HFD) has not been thoroughly explored. In this study, we aimed to determine the impact of a specific rise in cerebral ketone bodies on food intake and energy homeostasis regulation. A carotid infusion of ketone bodies was performed on mice to stimulate sensitive brain areas for 6 or 12 h. At each time point, food intake and different markers of energy homeostasis were analyzed to reveal the consequences of cerebral increase in ketone body level detection. First, an increase in food intake appeared over a 12-h period of brain ketone body perfusion. This stimulated food intake was associated with an increased expression of the hypothalamic neuropeptides NPY and AgRP as well as phosphorylated AMPK and is due to ketone bodies sensed by the brain, as blood ketone body levels did not change at that time. In parallel, gluconeogenesis and insulin sensitivity were transiently altered. Indeed, a dysregulation of glucose production and insulin secretion was observed after 6 h of ketone body perfusion, which reversed to normal at 12 h of perfusion. Altogether, these results suggest that an increase in brain ketone body concentration leads to hyperphagia and a transient perturbation of peripheral metabolic homeostasis.

scholarly journals Knockout of inositol-requiring enzyme 1α in pro-opiomelanocortin neurons decreases fat mass via increasing energy expenditure

Open Biology ◽  
2016 ◽  
Vol 6 (8) ◽  
pp. 160131 ◽  
Author(s):  
Yuzhong Xiao ◽  
Tingting Xia ◽  
Junjie Yu ◽  
Yalan Deng ◽  
Hao Liu ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Metabolic Diseases ◽  
Critical Role ◽  
Liver Steatosis ◽  
Leptin Resistance ◽  
Hormone Production ◽  
Melanocyte Stimulating Hormone ◽  
Diet Induced Obesity ◽  
Brown Adipose

Although numerous functions of inositol-requiring enzyme 1α (IRE1α) have been identified, a role of IRE1α in pro-opiomelanocortin (POMC) neurons in the arcuate nucleus of the hypothalamus is largely unknown. Here, we showed that mice lacking IRE1α specifically in POMC neurons (PIKO) are lean and resistant to high-fat diet-induced obesity and obesity-related insulin resistance, liver steatosis and leptin resistance. Furthermore, PIKO mice had higher energy expenditure, probably due to increased thermogenesis in brown adipose tissue. Additionally, α-melanocyte-stimulating hormone production was increased in the hypothalamus of PIKO mice. These results demonstrate that IRE1α in POMC neurons plays a critical role in the regulation of obesity and obesity-related metabolic disorders. Our results also suggest that IRE1α is not only an endoplasmic reticulum stress sensor, but also a new potential therapeutic target for obesity and obesity-related metabolic diseases.

Glutamatergic plasticity within neurocircuits of the dorsal vagal complex and the regulation of gastric functions

2021 ◽  
Author(s):  
Courtney Clyburn ◽  
Kirsteen N Browning
Keyword(s):  
Food Intake ◽  
Energy Homeostasis ◽  
Intestinal Secretion ◽  
Motor Nucleus ◽  
Glutamatergic Transmission ◽  
Gi Tract ◽  
Dorsal Motor Nucleus ◽  
Efferent Neurons ◽  
Rapid Transmission

The meticulous regulation of the gastrointestinal (GI) tract is required for the co-ordination of gastric motility and emptying, intestinal secretion, absorption, and transit as well as for the overarching management of food intake and energy homeostasis. Disruption of GI functions is associated with the development of severe GI disorders as well as the alteration of food intake and caloric balance. Functional GI disorders as well as the dysregulation of energy balance and food intake are frequently associated with, or result from, alterations in the central regulation of GI control. The faithful and rapid transmission of information from the stomach and upper GI tract to second order neurons of the nucleus of the tractus solitarius (NTS) relies on the delicate modulation of excitatory glutamatergic transmission, as does the relay of integrated signals from the NTS to parasympathetic efferent neurons of the dorsal motor nucleus of the vagus (DMV). Many studies have focused on understanding the physiological and pathophysiological modulation of these glutamatergic synapses, although their role in the control and regulation of GI functions has lagged behind that of cardiovascular and respiratory functions. The purpose of this review is to examine the current literature exploring the role of glutamatergic transmission in the DVC in the regulation of Gl functions.

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