Search results for " Homeostasis"

2015

The melanocortin system is one of the most important neuronal pathways involved in the regulation of food intake and is probably the best characterized. Agouti-related peptide (AgRP) and proopiomelanocortin (POMC) expressing neurons located in the arcuate nucleus of the hypothalamus are the key elements of this system. These two neuronal populations are sensitive to circulating molecules and receive many excitatory and inhibitory inputs from various brain areas. According to sensory and metabolic information they integrate, these neurons control different aspects of feeding behavior and orchestrate autonomic responses aimed at maintaining energy homeostasis. Interestingly, composition and a…

Impact of

2018

Drosophila melanogaster has been for over a century the model of choice of several neurobiologists to decipher the formation and development of the nervous system as well as to mirror the pathophysiological conditions of many human neurodegenerative diseases. The rare disease Friedreich’s ataxia (FRDA) is not an exception. Since the isolation of the responsible gene more than two decades ago, the analysis of the fly orthologue has proven to be an excellent avenue to understand the development and progression of the disease, to unravel pivotal mechanisms underpinning the pathology and to identify genes and molecules that might well be either disease biomarkers or promising targets for therap…

24S-hydroxycholesterol and cholesterol-24S-hydroxylase (CYP46A1) in the retina: from cholesterol homeostasis to pathophysiology of glaucoma.

2011

http://www.sciencedirect.com/; International audience; Free cholesterol is the predominant form of cholesterol in the neural retina. The vertebrate neural retina exhibits its own capacity to synthesize cholesterol and meets its demand also by taking it from the circulation. Defects in cholesterol synthesis and trafficking in the neural retina has detrimental consequences on its structure and function, highlighting the crucial importance of maintaining cholesterol homeostasis in the retina. Our purpose was to give a review on the functioning of the retina, the role of cholesterol and cholesterol metabolism therein, with special emphasis on cholesterol-24S-hydroxylase (CYP46A1). Similar to th…

In vivo consequences of cholesterol-24s-hydroxylase (CYP46A1) inhibition by voriconazole on cholesterol homeostasis and function in the rat retina

2011

Cholesterol 24S-hydroxylase (CYP46A1) converts cholesterol into 24S-hydroxycholesterol in neurons and participates in cholesterol homeostasis in the central nervous system, including the retina. We aimed to evaluate the consequences of CYP46A1 inhibition by voriconazole on cholesterol homeostasis and function in the retina. Rats received daily intraperitoneal injections of voriconazole (60mg/kg), minocycline (22mg/kg), voriconazole plus minocycline, or vehicle during five consecutive days. The rats were submitted to electroretinography to monitor retinal functionality. Cholesterol and 24S-hydroxycholesterol were measured in plasma, brain and retina by gas chromatography-mass spectrometry. T…

Role of ghrelin and leptin in the regulation of carbohydrate metabolism. Part I. Ghrelin

2012

Grelina jest polipeptydem wydzielanym przez komórki wydzielnicze błony śluzowej żołądka i jelit, jądro łukowate podwzgórza, a także przez komórki epsilon (e), które znajdują się w obrębie wysp trzustkowych. Grelina odgrywa ważną rolę w utrzymywaniu homeostazy energetycznej organizmu oraz wpływa na wewnątrzwydzielniczą funkcję trzustki i metabolizm glukozy. W regulacji homeostazy glukozy grelina bierze udział poprzez modulację wydzielania isuliny, jak i wrażliwości na insulinę. Wobec różnorodnych biologicznych skutków działania greliny, obecne badania poświęca się potencjalnym możliwościom ich modyfikowania. Dużo uwagi skupiono wokół enzymu zwanego O-acylo transferazą greliny (ghrelin O-acyl…

Macrophages as an Emerging Source of Wnt Ligands: Relevance in Mucosal Integrity

2019

The Wnt signaling pathway is a conserved pathway involved in important cellular processes such as the control of embryonic development, cellular polarity, cellular migration, and cell proliferation. In addition to playing a central role during embryogenesis, this pathway is also an essential part of adult homeostasis. Indeed, it controls the proliferation of epithelial cells in different organs such as intestine, lung, and kidney, and guarantees the maintenance of the mucosa in physiological conditions. The origin of this molecular pathway is the binding between Wnt ligands (belonging to a family of 19 different homologous secreted glycoproteins) and their specific membrane receptors, from …

Alzheimer's disease: new diagnostic and therapeutic tools.

2008

Abstract On March 19, 2008 a Symposium on Pathophysiology of Ageing and Age-Related diseases was held in Palermo, Italy. Here, the lectures of M. Racchi on History and future perspectives of Alzheimer Biomarkers and of G. Scapagnini on Cellular Stress Response and Brain Ageing are summarized. Alzheimer's disease (AD) is a heterogeneous and progressive neurodegenerative disease, which in Western society mainly accounts for clinica dementia. AD prevention is an important goal of ongoing research. Two objectives must be accomplished to make prevention feasible: i) individuals at high risk of AD need to be identified before the earliest symptoms become evident, by which time extensive neurodege…

Neural Stem Cells in the Adult Brain: From Benchside to Clinic

2012

Increasing evidence indicates that neural stem cells (NSCs) play an important role in sustaining cellular homeostasis and brain tissue restoration. The study of all mechanisms that control and modulate the function of NSC is a crucial step for the design of therapies against chronic neurodegenerative processes. In this special issue of the journal, we had the pleasure to edit the topic entitled “Neural Stem Cells in the Adult Brain: From Benchside to Clinic.” This special compilation of paper was aimed to provide a global forum for publications of original peer-reviewed manuscripts that reported original research findings in the field of adult neural stem cell, including short communication…

Relationship Between Oxidative Stress, ER Stress, and Inflammation in Type 2 Diabetes: The Battle Continues

2019

Type 2 diabetes (T2D) is a metabolic disorder characterized by hyperglycemia and insulin resistance in which oxidative stress is thought to be a primary cause. Considering that mitochondria are the main source of ROS, we have set out to provide a general overview on how oxidative stress is generated and related to T2D. Enhanced generation of reactive oxygen species (ROS) and oxidative stress occurs in mitochondria as a consequence of an overload of glucose and oxidative phosphorylation. Endoplasmic reticulum (ER) stress plays an important role in oxidative stress, as it is also a source of ROS. The tight interconnection between both organelles through mitochondrial-associated membranes (MAM…

Structure and Function of Desmosomes

2007

Desmosomes are prominent adhesion sites that are tightly associated with the cytoplasmic intermediate filament cytoskeleton providing mechanical stability in epithelia and also in several nonepithelial tissues such as cardiac muscle and meninges. They are unique in terms of ultrastructural appearance and molecular composition with cell type-specific variations. The dynamic assembly properties of desmosomes are important prerequisites for the acquisition and maintenance of tissue homeostasis. Disturbance of this equilibrium therefore not only compromises mechanical resilience but also affects many other tissue functions as becomes evident in various experimental scenarios and multiple diseas…