scholarly journals Leptin, Obesity, and Leptin Resistance: Where Are We 25 Years Later?

Nutrients ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2704 ◽  
Author(s):  
Andrea G. Izquierdo ◽  
Ana B. Crujeiras ◽  
Felipe F. Casanueva ◽  
Marcos C. Carreira
Keyword(s):  
Body Weight ◽  
Blood Brain Barrier ◽  
Clinical Utility ◽  
Molecular Mechanisms ◽  
Brain Barrier ◽  
Leptin Resistance ◽  
Blood Brain ◽  
Obese Subjects ◽  
Treatment Of Obesity ◽  
New Strategies

Leptin, a hormone that is capable of effectively reducing food intake and body weight, was initially considered for use in the treatment of obesity. However, obese subjects have since been found to have high levels of circulating leptin and to be insensitive to the exogenous administration of leptin. The inability of leptin to exert its anorexigenic effects in obese individuals, and therefore, the lack of clinical utility of leptin in obesity, is defined as leptin resistance. This phenomenon has not yet been adequately characterized. Elucidation of the molecular mechanisms underlying leptin resistance is of vital importance for the application of leptin as an effective treatment for obesity. Leptin must cross the blood–brain barrier (BBB) to reach the hypothalamus and exert its anorexigenic functions. The mechanisms involved in leptin transportation across the blood–brain barrier continue to be unclear, thereby preventing the clinical application of leptin in the treatment of obesity. In recent years, new strategies have been developed to recover the response to leptin in obesity. We have summarized these strategies in this review.

scholarly journals Pseudogene ACTBP2 increases blood–brain barrier permeability by promoting KHDRBS2 transcription through recruitment of KMT2D/WDR5 in Aβ1–42 microenvironment

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Qianshuo Liu ◽  
Xiaobai Liu ◽  
Defeng Zhao ◽  
Xuelei Ruan ◽  
Rui Su ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Vital Role ◽  
Brain Barrier ◽  
Blood Brain ◽  
Bbb Permeability ◽  
Novel Target ◽  
And Function

AbstractThe blood–brain barrier (BBB) has a vital role in maintaining the homeostasis of the central nervous system (CNS). Changes in the structure and function of BBB can accelerate Alzheimer’s disease (AD) development. β-Amyloid (Aβ) deposition is the major pathological event of AD. We elucidated the function and possible molecular mechanisms of the effect of pseudogene ACTBP2 on the permeability of BBB in Aβ1–42 microenvironment. BBB model treated with Aβ1–42 for 48 h were used to simulate Aβ-mediated BBB dysfunction in AD. We proved that pseudogene ACTBP2, RNA-binding protein KHDRBS2, and transcription factor HEY2 are highly expressed in ECs that were obtained in a BBB model in vitro in Aβ1–42 microenvironment. In Aβ1–42-incubated ECs, ACTBP2 recruits methyltransferases KMT2D and WDR5, binds to KHDRBS2 promoter, and promotes KHDRBS2 transcription. The interaction of KHDRBS2 with the 3′UTR of HEY2 mRNA increases the stability of HEY2 and promotes its expression. HEY2 increases BBB permeability in Aβ1–42 microenvironment by transcriptionally inhibiting the expression of ZO-1, occludin, and claudin-5. We confirmed that knocking down of Khdrbs2 or Hey2 increased the expression levels of ZO-1, occludin, and claudin-5 in APP/PS1 mice brain microvessels. ACTBP2/KHDRBS2/HEY2 axis has a crucial role in the regulation of BBB permeability in Aβ1–42 microenvironment, which may provide a novel target for the therapy of AD.

scholarly journals Mesenchymal Stem/Stromal Cell Therapy in Blood–Brain Barrier Preservation Following Ischemia: Molecular Mechanisms and Prospects

2021 ◽  
Vol 22 (18) ◽  
pp. 10045
Author(s):  
Phuong Thao Do ◽  
Chung-Che Wu ◽  
Yung-Hsiao Chiang ◽  
Chaur-Jong Hu ◽  
Kai-Yun Chen
Keyword(s):  
Stem Cells ◽  
Blood Brain Barrier ◽  
Molecular Mechanisms ◽  
Time Window ◽  
Brain Regions ◽  
Brain Barrier ◽  
Therapeutic Effects ◽  
Pathophysiological Mechanism ◽  
Cell Based Therapy ◽  
Blood Brain

Ischemic stroke is the leading cause of mortality and long-term disability worldwide. Disruption of the blood–brain barrier (BBB) is a prominent pathophysiological mechanism, responsible for a series of subsequent inflammatory cascades that exacerbate the damage to brain tissue. However, the benefit of recanalization is limited in most patients because of the narrow therapeutic time window. Recently, mesenchymal stem cells (MSCs) have been assessed as excellent candidates for cell-based therapy in cerebral ischemia, including neuroinflammatory alleviation, angiogenesis and neurogenesis promotion through their paracrine actions. In addition, accumulating evidence on how MSC therapy preserves BBB integrity after stroke may open up novel therapeutic targets for treating cerebrovascular diseases. In this review, we focus on the molecular mechanisms of MSC-based therapy in the ischemia-induced prevention of BBB compromise. Currently, therapeutic effects of MSCs for stroke are primarily based on the fundamental pathogenesis of BBB breakdown, such as attenuating leukocyte infiltration, matrix metalloproteinase (MMP) regulation, antioxidant, anti-inflammation, stabilizing morphology and crosstalk between cellular components of the BBB. We also discuss prospective studies to improve the effectiveness of MSC therapy through enhanced migration into defined brain regions of stem cells. Targeted therapy is a promising new direction and is being prioritized for extensive research.

scholarly journals Endothelium-targeted deletion of the miR-15a/16-1 cluster ameliorates blood-brain barrier dysfunction in ischemic stroke

2020 ◽  
Vol 13 (626) ◽  
pp. eaay5686 ◽  
Author(s):  
Feifei Ma ◽  
Ping Sun ◽  
Xuejing Zhang ◽  
Milton H. Hamblin ◽  
Ke-Jie Yin
Keyword(s):  
Ischemic Stroke ◽  
Blood Brain Barrier ◽  
Molecular Mechanisms ◽  
Neuronal Loss ◽  
Glucose Deprivation ◽  
Brain Barrier ◽  
Protein Abundance ◽  
Barrier Dysfunction ◽  
Small Noncoding Rnas ◽  
Blood Brain

The blood-brain barrier (BBB) maintains a stable brain microenvironment. Breakdown of BBB integrity during cerebral ischemia initiates a devastating cascade of events that eventually leads to neuronal loss. MicroRNAs are small noncoding RNAs that suppress protein expression, and we previously showed that the miR-15a/16-1 cluster is involved in the pathogenesis of ischemic brain injury. Here, we demonstrated that when subjected to experimentally induced stroke, mice with an endothelial cell (EC)–selective deletion of miR-15a/16-1 had smaller brain infarcts, reduced BBB leakage, and decreased infiltration of peripheral immune cells. These mice also showed reduced infiltration of proinflammatory M1-type microglia/macrophage in the peri-infarct area without changes in the number of resolving M2-type cells. Stroke decreases claudin-5 abundance, and we found that EC-selective miR-15a/16-1 deletion enhanced claudin-5 mRNA and protein abundance in ischemic mouse brains. In cultured mouse brain microvascular ECs (mBMECs), the miR-15a/16-1 cluster directly bound to the 3′ untranslated region (3′UTR) of Claudin-5, and lentivirus-mediated ablation of miR-15a/16-1 diminished oxygen-glucose deprivation (OGD)–induced down-regulation of claudin-5 mRNA and protein abundance and endothelial barrier dysfunction. These findings suggest that genetic deletion of endothelial miR-15a/16-1 suppresses BBB pathologies after ischemic stroke. Elucidating the molecular mechanisms of miR-15a/16-1–mediated BBB dysfunction may enable the discovery of new therapies for ischemic stroke.

scholarly journals Mechanisms of Blood–Brain Barrier Dysfunction in Traumatic Brain Injury

2020 ◽  
Vol 21 (9) ◽  
pp. 3344 ◽  
Author(s):  
Alison Cash ◽  
Michelle H. Theus
Keyword(s):  
Blood Brain Barrier ◽  
Intracellular Signaling ◽  
Molecular Mechanisms ◽  
Brain Injuries ◽  
The United States ◽  
Brain Barrier ◽  
Detection Methods ◽  
Secondary Injury ◽  
Barrier Dysfunction ◽  
Blood Brain

Traumatic brain injuries (TBIs) account for the majority of injury-related deaths in the United States with roughly two million TBIs occurring annually. Due to the spectrum of severity and heterogeneity in TBIs, investigation into the secondary injury is necessary in order to formulate an effective treatment. A mechanical consequence of trauma involves dysregulation of the blood–brain barrier (BBB) which contributes to secondary injury and exposure of peripheral components to the brain parenchyma. Recent studies have shed light on the mechanisms of BBB breakdown in TBI including novel intracellular signaling and cell–cell interactions within the BBB niche. The current review provides an overview of the BBB, novel detection methods for disruption, and the cellular and molecular mechanisms implicated in regulating its stability following TBI.

Impaired transport of leptin across the blood-brain barrier in obesity is acquired and reversible

2003 ◽  
Vol 285 (1) ◽  
pp. E10-E15 ◽  
Author(s):  
William A. Banks ◽  
Catherine L. Farrell
Keyword(s):  
Life Span ◽  
Blood Brain Barrier ◽  
Weight Reduction ◽  
Normal Population ◽  
Brain Barrier ◽  
Leptin Resistance ◽  
Blood Brain

Leptin resistance is a major cause of obesity in humans. A major component of this resistance is likely an impaired transport of leptin across the blood-brain barrier (BBB). The fattest subgroup of otherwise normal 12-mo-old CD-1 mice have severely impaired transport of leptin across the BBB. However, it is unknown whether these mice are born with a BBB impairment or acquire it with aging and obesity. Here, we found within an otherwise normal population of CD-1 mice that the 10% fattest mice gained weight throughout a 12-mo-life span, whereas the 10% thinnest mice gained little weight after 3 mo of age. The fattest mice acquired a progressive impairment in their ability to transport leptin across the BBB, whereas the thinnest mice had a rate of transport that did not change with age. Fasting fat mice for 24 h or treating them with leptin resulted in modest weight reduction and development of transport rates for leptin across the BBB similar to those of thin mice. These results show that, in obese CD-1 mice, the impaired transport of leptin across the BBB develops in tandem with obesity and is reversible with even modest weight reduction.

Nanoparticle- and Liposome-carried Drugs: New Strategies for Active Targeting and Drug Delivery Across Blood-brain Barrier

2013 ◽  
Vol 14 (6) ◽  
pp. 625-640 ◽  
Author(s):  
Martha Pinzon-Daza ◽  
Ivana Campia ◽  
Joanna Kopecka ◽  
Ruth Garzon ◽  
Dario Ghigo ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Active Targeting ◽  
Blood Brain ◽  
New Strategies

scholarly journals Starvation-induced regulation of carbohydrate transport at the blood–brain barrier is TGF-β-signaling dependent

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Helen Hertenstein ◽  
Ellen McMullen ◽  
Astrid Weiler ◽  
Anne Volkenhoff ◽  
Holger M Becker ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Molecular Mechanisms ◽  
Glucose Transporter ◽  
Brain Barrier ◽  
Nutrient Restriction ◽  
Sugar Transporters ◽  
Blood Brain ◽  
Evolutionarily Conserved ◽  
Carbohydrate Transport ◽  
Glucose Transporter Glut1

During hunger or malnutrition, animals prioritize alimentation of the brain over other organs to ensure its function and, thus, their survival. This protection, also-called brain sparing, is described from Drosophila to humans. However, little is known about the molecular mechanisms adapting carbohydrate transport. Here, we used Drosophila genetics to unravel the mechanisms operating at the blood–brain barrier (BBB) under nutrient restriction. During starvation, expression of the carbohydrate transporter Tret1-1 is increased to provide more efficient carbohydrate uptake. Two mechanisms are responsible for this increase. Similar to the regulation of mammalian GLUT4, Rab-dependent intracellular shuttling is needed for Tret1-1 integration into the plasma membrane; even though Tret1-1 regulation is independent of insulin signaling. In addition, starvation induces transcriptional upregulation that is controlled by TGF-β signaling. Considering TGF-β-dependent regulation of the glucose transporter GLUT1 in murine chondrocytes, our study reveals an evolutionarily conserved regulatory paradigm adapting the expression of sugar transporters at the BBB.

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