scholarly journals Autophagy-related genesatg7andbeclin1are essential for energy metabolism and survival during the larval-to-juvenile transition stage of zebrafish

2019 ◽  
Author(s):  
Suzan Attia Mawed ◽  
Jin Zhang ◽  
Fan Ren ◽  
Jie Mei
Keyword(s):  
Energy Homeostasis ◽  
Transition Period ◽  
Metabolic Stress ◽  
Transition Process ◽  
The Body ◽  
Molecular Evidence ◽  
Exogenous Feeding ◽  
Eukaryotic Organisms ◽  
Juvenile Development

AbstractHigh mortality is usually observed during the transition from larvae to juvenile in teleost which is related to the transition from endogenous to exogenous feeding. Autophagy is an evolutionary regulated cellular mechanism highly conserved in eukaryotic organisms to maintain energy homeostasis against stress including starvation. To investigate whether autophagy plays a role during the larval-juvenile transition, we generatedatg7andbeclin1zebrafish mutant lines using CRISPR/Cas9 technology. In this study, bothatg7andbeclin1null zebrafish exhibited a normal body confirmation; nevertheless, they completely died around 15 dpf and 9 dpf respectively. During larval-juvenile transition period,atg7andbeclin1mutants were unable to cope with the metabolic stress after yolk absorption at 5 dpf and fail to activate autophagy in response to nutrient restriction, and without external feeding, all mutants died nearly at 8 dpf. Dramatic defects in the intestine architecture and metabolic functions in the liver were observed even though providing larvae with an external food supply, suggesting that autophagy isn’t only important during yolk depletion but also within food plenty. Treatment with rapamycin, an activator of autophagy, could effectively extend the survival time of bothatg7andbeclin1null zebrafish through lowering the metabolic rate while it couldn’t activate autophagy in mutants via the canonical pathway. Our findings provided a molecular evidence for the physiological, histological and metabolic changes that occur during the transition process from the larval to the juvenile stages and the chief role of autophagy on the body metabolism during these turning milestones.Author summaryZebrafishDanio reriohas emergrd one of the most powerful research models for studying genes expression during early embryogenesis and postnatal development. On the basis of the cell mechanisms, Macroautphagy, a natural regulated pathway disassembles unnecessary or dysfunctional components orchestrated by more than 36 autophagy related-genes conserved from yeast to mammals. Among those genes areatg7andbeclin1which have been proved to play an important role in regulating post natal development in some mammals however their roles during zebrafish development still unedited. During this research, CRISPER/CAS9 were adopted to knowatg7andbeclin1knockout effects on the mutants’ metabolism during shifting from maternal yolk acquisition to exogenous feeding and the role of autophagy during the larvae to pre-juvenile development. Herein, we found out that larvae couldn’t abandon autophagy in both fasting and feeding conditions as larvae died earlier before pre-juvenile development despite feeding declaring the importance of autophagy not only to provide the cell with essential nutrients during starvation but also to get rid of cargos inside the eukaryotic cells. Briefly, if the larvae didn’t recycle those cargos due to autophagy perturbations, they will die despite providing suitable conditions including food and acclimatization.

scholarly journals An acetylation rheostat for the control of muscle energy homeostasis

2013 ◽  
Vol 51 (3) ◽  
pp. T101-T113 ◽  
Author(s):  
Keir Menzies ◽  
Johan Auwerx
Keyword(s):  
Skeletal Muscle ◽  
Mitochondrial Biogenesis ◽  
Energy Homeostasis ◽  
Cellular Stress ◽  
Metabolic Stress ◽  
Effector Proteins ◽  
The Body ◽  
Recent Developments ◽  
And Function

In recent years, the role of acetylation has gained ground as an essential modulator of intermediary metabolism in skeletal muscle. Imbalance in energy homeostasis or chronic cellular stress, due to diet, aging, or disease, translate into alterations in the acetylation levels of key proteins which govern bioenergetics, cellular substrate use, and/or changes in mitochondrial content and function. For example, cellular stress induced by exercise or caloric restriction can alter the coordinated activity of acetyltransferases and deacetylases to increase mitochondrial biogenesis and function in order to adapt to low energetic levels. The natural duality of these enzymes, as metabolic sensors and effector proteins, has helped biologists to understand how the body can integrate seemingly distinct signaling pathways to control mitochondrial biogenesis, insulin sensitivity, glucose transport, reactive oxygen species handling, angiogenesis, and muscle satellite cell proliferation/differentiation. Our review will summarize the recent developments related to acetylation-dependent responses following metabolic stress in skeletal muscle.

scholarly journals Functional Characterization of Spliceosomal Introns and Identification of U2, U4, and U5 snRNAs in the Deep-Branching Eukaryote Entamoeba histolytica

2007 ◽  
Vol 6 (6) ◽  
pp. 940-948 ◽  
Author(s):  
Carrie A. Davis ◽  
Michael P. S. Brown ◽  
Upinder Singh
Keyword(s):  
Entamoeba Histolytica ◽  
Splice Site ◽  
Expressed Sequence Tag ◽  
Functional Characterization ◽  
Molecular Evidence ◽  
Spliceosomal Introns ◽  
Accurate Expression ◽  
Eukaryotic Organisms

ABSTRACT Pre-mRNA splicing is essential to ensure accurate expression of many genes in eukaryotic organisms. In Entamoeba histolytica, a deep-branching eukaryote, approximately 30% of the annotated genes are predicted to contain introns; however, the accuracy of these predictions has not been tested. In this study, we mined an expressed sequence tag (EST) library representing 7% of amoebic genes and found evidence supporting splicing of 60% of the testable intron predictions, the majority of which contain a GUUUGU 5′ splice site and a UAG 3′ splice site. Additionally, we identified several splice site misannotations, evidence for the existence of 30 novel introns in previously annotated genes, and identified novel genes through uncovering their spliced ESTs. Finally, we provided molecular evidence for the E. histolytica U2, U4, and U5 snRNAs. These data lay the foundation for further dissection of the role of RNA processing in E. histolytica gene expression.

Molecular evidence for the role of a ferric reductase in iron transport

2002 ◽  
Vol 30 (4) ◽  
pp. 722-724 ◽  
Author(s):  
A. T. McKie ◽  
G. O. Latunde-Dada ◽  
S. Miret ◽  
J. A. McGregor ◽  
G. J. Anderson ◽  
...  
Keyword(s):  
Reductase Activity ◽  
The Body ◽  
Molecular Evidence ◽  
Ferric Reductase ◽  
Divalent Metal Transporter 1 ◽  
Divalent Metal Transporter ◽  
Metal Transporter ◽  
Cytochrome B561 ◽  
Haem Protein

Duodenal cytochrome b (Dcytb) is a haem protein similar to the cytochrome b561 protein family. Dcytb is highly expressed in duodenal brush-border membrane and is implicated in dietary iron absorption by reducing dietary ferric iron to the ferrous form for transport via Nramp2/DCT1 (divalent-cation transporter 1)/DMT1 (divalent metal-transporter 1). The protein is expressed in other tissues and may account for ferric reductase activity at other sites in the body.

scholarly journals Current Understanding of Role of Vesicular Transport in Salt Secretion by Salt Glands in Recretohalophytes

2021 ◽  
Vol 22 (4) ◽  
pp. 2203 ◽  
Author(s):  
Chaoxia Lu ◽  
Fang Yuan ◽  
Jianrong Guo ◽  
Guoliang Han ◽  
Chengfeng Wang ◽  
...  
Keyword(s):  
Vesicular Transport ◽  
Salt Gland ◽  
Soil Salinization ◽  
The Body ◽  
Molecular Evidence ◽  
Salt Glands ◽  
Functional Roles ◽  
Secretion Process ◽  
Salt Secretion

Soil salinization is a serious and growing problem around the world. Some plants, recognized as the recretohalophytes, can normally grow on saline–alkali soil without adverse effects by secreting excessive salt out of the body. The elucidation of the salt secretion process is of great significance for understanding the salt tolerance mechanism adopted by the recretohalophytes. Between the 1950s and the 1970s, three hypotheses, including the osmotic potential hypothesis, the transfer system similar to liquid flow in animals, and vesicle-mediated exocytosis, were proposed to explain the salt secretion process of plant salt glands. More recently, increasing evidence has indicated that vesicular transport plays vital roles in salt secretion of recretohalophytes. Here, we summarize recent findings, especially regarding the molecular evidence on the functional roles of vesicular trafficking in the salt secretion process of plant salt glands. A model of salt secretion in salt gland is also proposed.

scholarly journals mTOR Pathway is Involved in Energy Homeostasis Regulation as a Part of the Gut–Brain Axis

2020 ◽  
Vol 21 (16) ◽  
pp. 5715
Author(s):  
Veronica Pena-Leon ◽  
Raquel Perez-Lois ◽  
Luisa Maria Seoane
Keyword(s):  
Energy Homeostasis ◽  
The Body ◽  
Mtor Signaling ◽  
Physiological Processes ◽  
Energy Sensor ◽  
Relevant Role ◽  
Regulate Food Intake ◽  
Glucose And Lipid Homeostasis ◽  
Treatment Of Obesity

Mammalian, or mechanic, target of rapamycin (mTOR) signaling is a crucial factor in the regulation of the energy balance that functions as an energy sensor in the body. The present review explores how the mTOR/S6k intracellular pathway is involved in modulating the production of different signals such as ghrelin and nesfatin-1 in the gastrointestinal tract to regulate food intake and body weight. The role of gastric mTOR signaling in different physiological processes was studied in depth through different genetic models that allow the modulation of mTOR signaling in the stomach and specifically in gastric X/A type cells. It has been described that mTOR signaling in X/A-like gastric cells has a relevant role in the regulation of glucose and lipid homeostasis due to its interaction with different organs such as liver and adipose tissue. These findings highlight possible therapeutic strategies, with the gut–brain axis being one of the most promising targets in the treatment of obesity.

Chronic intracerebroventricular infusion of MCH causes obesity in mice

2003 ◽  
Vol 284 (3) ◽  
pp. E583-E588 ◽  
Author(s):  
Akira Gomori ◽  
Akane Ishihara ◽  
Masahiko Ito ◽  
Satoshi Mashiko ◽  
Hiroko Matsushita ◽  
...  
Keyword(s):  
Body Weight ◽  
Weight Control ◽  
Energy Homeostasis ◽  
The Body ◽  
Intracerebroventricular Infusion ◽  
Melanin Concentrating Hormone ◽  
Important Regulator ◽  
Obesity In Mice ◽  
Body Weight Control

Melanin-concentrating hormone (MCH) is a cyclic amino acid neuropeptide localized in the lateral hypothalamus. Although MCH is thought to be an important regulator of feeding behavior, the involvement of this peptide in body weight control has been unclear. To examine the role of MCH in the development of obesity, we assessed the effect of chronic intracerebroventricular infusion of MCH in C57BL/6J mice that were fed with regular or moderately high-fat (MHF) diets. Intracerebroventricular infusion of MCH (10 μg/day for 14 days) caused a slight but significant increase in body weight in mice maintained on the regular diet. In the MHF diet-fed mice, MCH more clearly increased the body weight accompanied by a sustained hyperphagia and significant increase in fat and liver weights. Plasma glucose, insulin, and leptin levels were also increased in the MCH-treated mice fed the MHF diet. These results suggest that chronic stimulation of the brain MCH system causes obesity in mice and imply that MCH may have a major role in energy homeostasis.

scholarly journals Circadian Rhythms of the Hypothalamus: From Function to Physiology

2021 ◽  
Vol 3 (1) ◽  
pp. 189-226
Author(s):  
Rachel Van Drunen ◽  
Kristin Eckel-Mahan
Keyword(s):  
Circadian Rhythms ◽  
Energy Homeostasis ◽  
Environmental Changes ◽  
Neurological Diseases ◽  
Epidemiological Studies ◽  
Internal Clock ◽  
The Body ◽  
Hypothalamic Nuclei ◽  
Increased Risk

The nearly ubiquitous expression of endogenous 24 h oscillations known as circadian rhythms regulate the timing of physiological functions in the body. These intrinsic rhythms are sensitive to external cues, known as zeitgebers, which entrain the internal biological processes to the daily environmental changes in light, temperature, and food availability. Light directly entrains the master clock, the suprachiasmatic nucleus (SCN) which lies in the hypothalamus of the brain and is responsible for synchronizing internal rhythms. However, recent evidence underscores the importance of other hypothalamic nuclei in regulating several essential rhythmic biological functions. These extra-SCN hypothalamic nuclei also express circadian rhythms, suggesting distinct regions that oscillate either semi-autonomously or independent of SCN innervation. Concurrently, the extra-SCN hypothalamic nuclei are also sensitized to fluctuations in nutrient and hormonal signals. Thus, food intake acts as another powerful entrainer for the hypothalamic oscillators’ mediation of energy homeostasis. Ablation studies and genetic mouse models with perturbed extra-SCN hypothalamic nuclei function reveal their critical downstream involvement in an array of functions including metabolism, thermogenesis, food consumption, thirst, mood and sleep. Large epidemiological studies of individuals whose internal circadian cycle is chronically disrupted reveal that disruption of our internal clock is associated with an increased risk of obesity and several neurological diseases and disorders. In this review, we discuss the profound role of the extra-SCN hypothalamic nuclei in rhythmically regulating and coordinating body wide functions.

scholarly journals Role of the phosphocreatine system on energetic homeostasis in skeletal and cardiac muscles

2014 ◽  
Vol 12 (1) ◽  
pp. 126-131 ◽  
Author(s):  
Lucas Guimarães-Ferreira
Keyword(s):  
Creatine Kinase ◽  
Adenosine Triphosphate ◽  
Energy Homeostasis ◽  
Subcellular Location ◽  
Adenosine Diphosphate ◽  
The Body ◽  
Pathological Conditions ◽  
Cardiac Muscles ◽  
Energy Buffer

Adenosine triphosphate is the present energy currency in the body, and is used in various cellular and indispensable processes for the maintenance of cell homeostasis. The regeneration mechanisms of adenosine triphosphate, from the product of its hydrolysis – adenosine diphosphate – are therefore necessary. Phosphocreatine is known as its quickest form of regeneration, by means of the enzyme creatine kinase. Thus, the primary function of this system is to act as a temporal energy buffer. Nevertheless, over the years, several other functions were attributed to phosphocreatine. This occurs as various isoforms of creatine kinase isoforms have been identified with a distinct subcellular location and functionally coupled with the sites that generate and use energy, in the mitochondria and cytosol, respectively. The present study discussed the central and complex role that the phosphocreatine system performs in energy homeostasis in muscle cells, as well as its alterations in pathological conditions.

scholarly journals Central Regulation of Metabolism by Growth Hormone

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 129
Author(s):  
Jose Donato ◽  
Frederick Wasinski ◽  
Isadora C. Furigo ◽  
Martin Metzger ◽  
Renata Frazão
Keyword(s):  
Growth Hormone ◽  
Energy Homeostasis ◽  
Current Knowledge ◽  
Metabolic Stress ◽  
Wide Distribution ◽  
Tissue Growth ◽  
Neuronal Populations ◽  
Hypothalamic Nuclei ◽  
The Brain

Growth hormone (GH) is secreted by the pituitary gland, and in addition to its classical functions of regulating height, protein synthesis, tissue growth, and cell proliferation, GH exerts profound effects on metabolism. In this regard, GH stimulates lipolysis in white adipose tissue and antagonizes insulin’s effects on glycemic control. During the last decade, a wide distribution of GH-responsive neurons were identified in numerous brain areas, especially in hypothalamic nuclei, that control metabolism. The specific role of GH action in different neuronal populations is now starting to be uncovered, and so far, it indicates that the brain is an important target of GH for the regulation of food intake, energy expenditure, and glycemia and neuroendocrine changes, particularly in response to different forms of metabolic stress such as glucoprivation, food restriction, and physical exercise. The objective of the present review is to summarize the current knowledge about the potential role of GH action in the brain for the regulation of different metabolic aspects. The findings gathered here allow us to suggest that GH represents a hormonal factor that conveys homeostatic information to the brain to produce metabolic adjustments in order to promote energy homeostasis.

scholarly journals Neuroanatomical Framework of the Metabolic Control of Reproduction

2018 ◽  
Vol 98 (4) ◽  
pp. 2349-2380 ◽  
Author(s):  
Jennifer W. Hill ◽  
Carol F. Elias
Keyword(s):  
Energy Homeostasis ◽  
Protein Biosynthesis ◽  
Pubertal Development ◽  
Metabolic Stress ◽  
Reproductive Function ◽  
Metabolic Dysfunction ◽  
Physiological Processes ◽  
Extra Energy ◽  
The Brain

A minimum amount of energy is required for basic physiological processes, such as protein biosynthesis, thermoregulation, locomotion, cardiovascular function, and digestion. However, for reproductive function and survival of the species, extra energy stores are necessary. Production of sex hormones and gametes, pubertal development, pregnancy, lactation, and parental care all require energy reserves. Thus the physiological systems that control energy homeostasis and reproductive function coevolved in mammals to support both individual health and species subsistence. In this review, we aim to gather scientific knowledge produced by laboratories around the world on the role of the brain in integrating metabolism and reproduction. We describe essential neuronal networks, highlighting key nodes and potential downstream targets. Novel animal models and genetic tools have produced substantial advances, but critical gaps remain. In times of soaring worldwide obesity and metabolic dysfunction, understanding the mechanisms by which metabolic stress alters reproductive physiology has become crucial for human health.

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