Endothelin-1 is over-expressed in amyotrophic lateral sclerosis and induces motor neuron cell death

Astrocyte-Neuron Interactions Contributing to Amyotrophic Lateral Sclerosis Progression

Amyotrophic lateral sclerosis (ALS) is a complex disease impacting motor neurons of the brain, brainstem, and spinal cord. Disease etiology is quite heterogeneous with over 40 genes causing the disease and a vast ~90% of patients having no prior family history. Astrocytes are major contributors to ALS, particularly through involvement in accelerating disease progression. Through study of genetic forms of disease including SOD1, TDP43, FUS, C9orf72, VCP, TBK1, and more recently patient-derived cells from sporadic individuals, many biological mechanisms have been identified to cause intrinsic or glial-mediated neurotoxicity to motor neurons. Overall, many of the normally supportive and beneficial roles that astrocytes contribute to neuronal health and survival instead switch to become deleterious and neurotoxic. While the exact pathways may differ based on disease-origin, altered astrocyte-neuron communication is a common feature of ALS. Within this chapter, distinct genetic forms are examined in detail, along with what is known from sporadic patient-derived cells. Overall, this chapter highlights the interplay between astrocytes and neurons in this complex disease and describes the key features underlying: astrocyte-mediated motor neuron toxicity, excitotoxicity, oxidative/nitrosative stress, protein dyshomeostasis, metabolic imbalance, inflammation, trophic factor withdrawal, blood-brain/blood-spinal cord barrier involvement, disease spreading, and the extracellular matrix/cell adhesion/TGF-β signaling pathways.

In Silico Exploration of Metabolically Active Peptides as Potential Therapeutic Agents against Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is regarded as a fatal neurodegenerative disease that is featured by progressive damage of the upper and lower motor neurons. To date, over 45 genes have been found to be connected with ALS pathology. The aim of this work was to computationally identify unique sets of protein hydrolysate peptides that could serve as therapeutic agents against ALS. Computational methods which include target prediction, protein-protein interaction, and peptide-protein molecular docking were used. The results showed that the network of critical ALS-associated genes consists of ATG16L2, SCFD1, VAC15, VEGFA, KEAP1, KIF5A, FIG4, TUBA4A, SIGMAR1, SETX, ANXA11, HNRNPL, NEK1, C9orf72, VCP, RPSA, ATP5B, and SOD1 together with predicted kinases such as AKT1, CDK4, DNAPK, MAPK14, and ERK2 in addition to transcription factors such as MYC, RELA, ZMIZ1, EGR1, TRIM28, and FOXA2. The identified molecular targets of the peptides that support multi-metabolic components in ALS pathogenesis include cyclooxygenase-2, angiotensin I-converting enzyme, dipeptidyl peptidase IV, X-linked inhibitor of apoptosis protein 3, and endothelin receptor ET-A. Overall, the results showed that AGL, APL, AVK, IIW, PVI, and VAY peptides are promising candidates for further study. Future work would be needed to validate the therapeutic properties of these hydrolysate peptides by in vitro and in vivo approaches.

Endothelin-1, over-expressed in SOD1G93A mice, aggravates injury of NSC34-hSOD1G93A cells through complicated molecular mechanism revealed by quantitative proteomics analysis

Endothelin-1 (ET-1), a secreted signaling peptide, is suggested to be involved in multiple actions in various tissues including the brain, but its role in amyotrophic lateral sclerosis (ALS) remains unknown. In this study, we detected the expression changes as well as the cellular localization of ET-1, endothelin A (ET-A) and endothelin B (ET-B) receptors in spinal cord of transgenic SOD1-G93A (TgSOD1-G93A) mice, which showed that the two ET receptors (ET-Rs) expressed mainly on neurons and decreased as the disease progressed especially ET-B, while ET-1 expression was up-regulated and primarily localized on astrocytes. We then explored the possible mechanisms underlying the effect of ET-1 on cultured NSC34-hSOD1G93A cell model. ET-1 showed toxic effect on motor neurons (MNs), which can be rescued by the selective ET-A receptor antagonist BQ-123 or ET-B receptor antagonist BQ-788, suggesting that clinically used ET-Rs pan-antagonist could be a potential strategy for ALS. Using proteomic analysis, we revealed that 110 proteins were differentially expressed in NSC34-hSOD1G93A cells after ET-1 treatment, of which 54 were up-regulated and 56 were down-regulated. Bioinformatic analysis showed that the differentially expressed proteins (DEPs) were primarily enriched in hippo signaling pathway-multiple species, ABC transporters, ErbB signaling pathway and so on. These results provide further insights on the potential roles of ET-1 in ALS and present a new promising therapeutic target to protect MNs of ALS.

Patching Up the Permeability: The Role of Stem Cells in Lessening Neurovascular Damage in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a debilitating disease with poor prognosis. The pathophysiology of ALS is commonly debated, with theories involving inflammation, glutamate excitotoxity, oxidative stress, mitochondria malfunction, neurofilament accumulation, inadequate nutrients or growth factors, and changes in glial support predominating. These underlying pathological mechanisms, however, act together to weaken the blood brain barrier and blood spinal cord barrier, collectively considered as the blood central nervous system barrier (BCNSB). Altering the impermeability of the BCNSB impairs the neurovascular unit, or interdependent relationship between the brain and advances the concept that ALS is has a significant neurovascular component contributing to its degenerative presentation. This unique categorization of ALS opens a variety of treatment options targeting the reestablishment of BCNSB integrity. This review will critically assess the evidence implicating the significant neurovascular components of ALS pathophysiology, while also offering an in-depth discussion regarding the use of stem cells to repair these pathological changes within the neurovascular unit.

Investigating the specificity of endothelin-traps as a potential therapeutic tool for endothelin-1 related disorders

BACKGROUND

Endothelin (ET)-traps are Fc-fusion proteins with a design based on the physiological receptors of ET-1. Previous work has shown that use of the selected ET-traps potently and significantly reduces different markers of diabetes pathology back to normal, non-disease levels.

AIM

To demonstrate the selected ET-traps potently and significantly bind to ET-1.

METHODS

We performed phage display experiments to test different constructs of ET-traps, and conducted bio-layer interferometry binding assays to verify that the selected ET-traps bind specifically to ET-1 and display binding affinity in the double-digit picomolar range (an average of 73.8 rM, n = 6).

RESULTS

These experiments have confirmed our choice of the final ET-traps and provided proof-of-concept for the potential use of constructs as effective biologics for diseases associated with pathologically elevated ET-1.

CONCLUSION

There is increased need for such therapeutics as they could help save millions of lives around the world.

Endothelin receptor type A is involved in the development of oxaliplatin-induced mechanical allodynia and cold allodynia acting through spinal and peripheral mechanisms in rats

Oxaliplatin, a platinum-based chemotherapeutic agent, frequently causes severe neuropathic pain typically encompassing cold allodynia and long-lasting mechanical allodynia. Endothelin has been shown to modulate nociceptive transmission in a variety of pain disorders. However, the action of endothelin varies greatly depending on many variables, including pain causes, receptor types (endothelin type A (ET_A) and B (ET_B) receptors) and organs (periphery and spinal cord). Therefore, in this study, we investigated the role of endothelin in a Sprague–Dawley rat model of oxaliplatin-induced neuropathic pain. Intraperitoneal administration of bosentan, a dual ET_A/ET_B receptor antagonist, effectively blocked the development or prevented the onset of both cold allodynia and mechanical allodynia. The preventive effects were exclusively mediated by ET_A receptor antagonism. Intrathecal administration of an ET_A receptor antagonist prevented development of long-lasting mechanical allodynia but not cold allodynia. In marked contrast, an intraplantar ET_A receptor antagonist had a suppressive effect on cold allodynia but only had a partial and transient effect on mechanical allodynia. In conclusion, ET_A receptor antagonism effectively prevented long-lasting mechanical allodynia through spinal and peripheral actions, while cold allodynia was prevented through peripheral actions.

Neurovascular signals in amyotrophic lateral sclerosis

The neurovascular system (NVS) is a complex anatomic-functional unit that synergically works to maintain organs/tissues homeostasis of the entire body. NVS alterations have recently emerged as a common distinct feature in the pathogenesis of several neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). Despite their undeniable involvement, neurovascular signalling pathways remain still far unknown in ALS. This review underlines the importance of endothelial, mural, and fibroblast cells as novel targets for ALS investigation and identifies in the interplay between neuronal and vascular systems the way to disclose novel molecular mechanisms behind the pathogenesis of ALS.

Endothelin-1 axes in the framework of predictive, preventive and personalised (3P) medicine

Endothelin-1 (ET-1) is involved in the regulation of a myriad of processes highly relevant for physical and mental well-being; female and male health; in the modulation of senses, pain, stress reactions and drug sensitivity as well as healing processes, amongst others. Shifted ET-1 homeostasis may influence and predict the development and progression of suboptimal health conditions, metabolic impairments with cascading complications, ageing and related pathologies, cardiovascular diseases, neurodegenerative pathologies, aggressive malignancies, modulating, therefore, individual outcomes of both non-communicable and infectious diseases such as COVID-19. This article provides an in-depth analysis of the involvement of ET-1 and related regulatory pathways in physiological and pathophysiological processes and estimates its capacity as a predictor of ageing and related pathologies,a sensor of lifestyle quality and progression of suboptimal health conditions to diseases for their targeted preventionand as a potent target for cost-effective treatments tailored to the person.

Network Analysis Identifies Sex-Specific Gene Expression Changes in Blood of Amyotrophic Lateral Sclerosis Patients

Understanding the molecular mechanisms underlying the pathogenesis of amyotrophic lateral sclerosis (ALS), a devastating neurodegenerative disease, is a major challenge. We used co-expression networks implemented by the SWitch Miner software to identify switch genes associated with drastic transcriptomic changes in the blood of ALS patients. Functional analyses revealed that switch genes were enriched in pathways related to the cell cycle, hepatitis C, and small cell lung cancer. Analysis of switch genes by sex revealed that switch genes from males were associated with metabolic pathways, including PI3K-AKT, sphingolipid, carbon metabolism, FOXO, and AMPK signaling. In contrast, female switch genes related to infectious diseases, inflammation, apoptosis, and atherosclerosis. Furthermore, eight switch genes showed sex-specific gene expression patterns. Collectively, we identified essential genes and pathways that may explain sex differences observed in ALS. Future studies investigating the potential role of these genes in driving disease disparities between males and females with ALS are warranted.

Endothelin ETB Receptor-Mediated Astrocytic Activation: Pathological Roles in Brain Disorders

In brain disorders, reactive astrocytes, which are characterized by hypertrophy of the cell body and proliferative properties, are commonly observed. As reactive astrocytes are involved in the pathogenesis of several brain disorders, the control of astrocytic function has been proposed as a therapeutic strategy, and target molecules to effectively control astrocytic functions have been investigated. The production of brain endothelin-1 (ET-1), which increases in brain disorders, is involved in the pathophysiological response of the nervous system. Endothelin B (ET_B) receptors are highly expressed in reactive astrocytes and are upregulated by brain injury. Activation of astrocyte ET_B receptors promotes the induction of reactive astrocytes. In addition, the production of various astrocyte-derived factors, including neurotrophic factors and vascular permeability regulators, is regulated by ET_B receptors. In animal models of Alzheimer’s disease, brain ischemia, neuropathic pain, and traumatic brain injury, ET_B-receptor-mediated regulation of astrocytic activation has been reported to improve brain disorders. Therefore, the astrocytic ET_B receptor is expected to be a promising drug target to improve several brain disorders. This article reviews the roles of ET_B receptors in astrocytic activation and discusses its possible applications in the treatment of brain disorders.

AAV Targeting of Glial Cell Types in the Central and Peripheral Nervous System and Relevance to Human Gene Therapy

Different glial cell types are found throughout the central (CNS) and peripheral nervous system (PNS), where they have important functions. These cell types are also involved in nervous system pathology, playing roles in neurodegenerative disease and following trauma in the brain and spinal cord (astrocytes, microglia, oligodendrocytes), nerve degeneration and development of pain in peripheral nerves (Schwann cells, satellite cells), retinal diseases (Müller glia) and gut dysbiosis (enteric glia). These cell type have all been proposed as potential targets for treating these conditions. One approach to target these cell types is the use of gene therapy to modify gene expression. Adeno-associated virus (AAV) vectors have been shown to be safe and effective in targeting cells in the nervous system and have been used in a number of clinical trials. To date, a number of studies have tested the use of different AAV serotypes and cell-specific promoters to increase glial cell tropism and expression. However, true glial-cell specific targeting for a particular glial cell type remains elusive. This review provides an overview of research into developing glial specific gene therapy and discusses some of the issues that still need to be addressed to make glial cell gene therapy a clinical reality.

Mesenchymal stem cells instruct a beneficial phenotype in reactive astrocytes

Transplanted mesenchymal stromal/stem cells (MSC) ameliorate the clinical course of experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis (MS), reducing inflammation and demyelination. These effects are mediated by instructive cross-talk between MSC and immune and neural cells. Astroglial reaction to injury is a prominent feature of both EAE and MS. Astrocytes constitute a relevant target to control disease onset and progression and, based on their potential to acquire stem cell properties in situ, to foster recovery in the post-acute phase of pathology. We have assessed how MSC impact astrocytes in vitro and ex vivo in EAE. Expression of astroglial factors implicated in EAE pathogenesis was quantified by real-time PCR in astrocytes co-cultured with MSC or isolated from EAE cerebral cortex; astrocyte morphology and expression of activation markers were analyzed by confocal microscopy. The acquisition of neural stem cell properties by astrocytes was evaluated by neurosphere assay. Our study shows that MSC prevented astrogliosis, reduced mRNA expression of inflammatory cytokines that sustain immune cell infiltration in EAE, as well as protein expression of endothelin-1, an astrocyte-derived factor that inhibits remyelination and contributes to neurodegeneration and disease progression in MS. Moreover, our data reveal that MSC promoted the acquisition of progenitor traits by astrocytes. These data indicate that MSC attenuate detrimental features of reactive astroglia and, based on the reacquisition of stem cell properties, also suggest that astrocytes may be empowered in their protective and reparative actions by MSC.

Omics-based exploration and functional validation of neurotrophic factors and histamine as therapeutic targets in ALS

A plethora of genetic and molecular mechanisms have been implicated in the pathophysiology of the heterogeneous and multifactorial amyotrophic lateral sclerosis (ALS) disease, and hence the conventional "one target-one drug" paradigm has failed so far to provide effective therapeutic solutions, precisely because of the complex nature of ALS. This review intends to highlight how the integration of emerging "omics" approaches may provide a rational foundation for the comprehensive exploration of molecular pathways and dynamic interactions involved in ALS, for the identification of candidate targets and biomarkers that will assist in the rapid diagnosis and prognosis, lastly for the stratification of patients into different subgroups with the aim of personalized therapeutic strategies. To this purpose, particular emphasis will be placed on some potential therapeutic targets, including neurotrophic factors and histamine signaling that both have emerged as dysregulated at different omics levels in specific subgroups of ALS patients, and have already shown promising results in in vitro and in vivo models of ALS. To conclude, we will discuss about the utility of using integrated omics coupled with network-based approaches to provide additional guidance for personalization of medicine applications in ALS.

ET-traps offer a potential therapeutic tool for use in different autoimmune diseases

Research shows that endothelin (ET)-traps are a potential therapy for diabetes. Given that type 1 diabetes mellitus (T1DM) is an autoimmune disorder, ET-traps could also have an efficacious, therapeutic effect on other autoimmune diseases associated with pathologically elevated ET-1. Here, we describe those different autoimmune diseases that might benefit from a tool such as ET-traps, which potently sequester these elevated levels of ET-1. We also discuss the current use of ET receptor (ETR) antagonists and the associated adverse effects, and how ET-traps are associated with no toxicity and potentially offer a superior alternative. ET-traps could be used against different autoimmune diseases and, therefore, are a novel therapeutic tool for such conditions.

Genetic targeting of astrocytes to combat neurodegenerative disease

Astrocytes, glial cells that interact extensively with neurons and other support cells throughout the central nervous system, have recently come under the spotlight for their potential contribution to, or potential regenerative role in a host of neurodegenerative disorders. It is becoming increasingly clear that astrocytes, in concert with microglial cells, activate intrinsic immunological pathways in the setting of neurodegenerative injury, although the direct and indirect consequences of such activation are still largely unknown. We review the current literature on the astrocyte’s role in several neurodegenerative diseases, as well as highlighting recent advances in genetic manipulation of astrocytes that may prove critical to modulating their response to neurological injury, potentially combatting neurodegenerative damage.

Dual Roles of Astrocyte-Derived Factors in Regulation of Blood-Brain Barrier Function after Brain Damage

The blood-brain barrier (BBB) is a major functional barrier in the central nervous system (CNS), and inhibits the extravasation of intravascular contents and transports various essential nutrients between the blood and the brain. After brain damage by traumatic brain injury, cerebral ischemia and several other CNS disorders, the functions of the BBB are disrupted, resulting in severe secondary damage including brain edema and inflammatory injury. Therefore, BBB protection and recovery are considered novel therapeutic strategies for reducing brain damage. Emerging evidence suggests key roles of astrocyte-derived factors in BBB disruption and recovery after brain damage. The astrocyte-derived vascular permeability factors include vascular endothelial growth factors, matrix metalloproteinases, nitric oxide, glutamate and endothelin-1, which enhance BBB permeability leading to BBB disruption. By contrast, the astrocyte-derived protective factors include angiopoietin-1, sonic hedgehog, glial-derived neurotrophic factor, retinoic acid and insulin-like growth factor-1 and apolipoprotein E which attenuate BBB permeability resulting in recovery of BBB function. In this review, the roles of these astrocyte-derived factors in BBB function are summarized, and their significance as therapeutic targets for BBB protection and recovery after brain damage are discussed.

The Stress-Inducible Protein DRR1 Exerts Distinct Effects on Actin Dynamics

Cytoskeletal dynamics are pivotal to memory, learning, and stress physiology, and thus psychiatric diseases. Downregulated in renal cell carcinoma 1 (DRR1) protein was characterized as the link between stress, actin dynamics, neuronal function, and cognition. To elucidate the underlying molecular mechanisms, we undertook a domain analysis of DRR1 and probed the effects on actin binding, polymerization, and bundling, as well as on actin-dependent cellular processes. Methods: DRR1 domains were cloned and expressed as recombinant proteins to perform in vitro analysis of actin dynamics (binding, bundling, polymerization, and nucleation). Cellular actin-dependent processes were analyzed in transfected HeLa cells with fluorescence recovery after photobleaching (FRAP) and confocal microscopy. Results: DRR1 features an actin binding site at each terminus, separated by a coiled coil domain. DRR1 enhances actin bundling, the cellular F-actin content, and serum response factor (SRF)-dependent transcription, while it diminishes actin filament elongation, cell spreading, and actin treadmilling. We also provide evidence for a nucleation effect of DRR1. Blocking of pointed end elongation by addition of profilin indicates DRR1 as a novel barbed end capping factor. Conclusions: DRR1 impacts actin dynamics in several ways with implications for cytoskeletal dynamics in stress physiology and pathophysiology.

The C9ORF72 Gene, Implicated in Amyotrophic Lateral Sclerosis and Frontotemporal Dementia, Encodes a Protein That Functions in Control of Endothelin and Glutamate Signaling

A GGGGCC repeat expansion in the C9ORF72 (C9) gene is the most common known cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. Several mechanisms have been proposed to account for its toxicity, including the possibility that reduced C9 protein levels contribute to disease. To investigate this possibility, we examined the effects of reduced C9 levels in several cell systems. We first showed that C9 knockdown (KD) in U87 glioblastoma cells results in striking morphological changes, including vacuolization and alterations in cell size. Unexpectedly, RNA analysis revealed changes in expression of many genes, including genes involved in endothelin (EDN) signaling and immune system pathways and multiple glutamate cycling genes (e.g., EAAT2), which were verified in several cell models, including astrocytes and brain samples from C9-positive patients. Consistent with deregulation of the glutamate cycling genes, elevated intracellular glutamate was detected in both KD cells and patient astrocytes. Importantly, levels of mRNAs encoding EDN1 and its receptors, known to be elevated in ALS, were sharply increased by C9 KD, likely resulting from an observed activation of NF-κB signaling and/or a possible role of a C9 isoform in gene control.

A novel neuroregenerative approach using ET(B) receptor agonist, IRL-1620, to treat CNS disorders

Endothelin B (ET(B)) receptors present in abundance the central nervous system (CNS) have been shown to have significant implications in its development and neurogenesis. We have targeted ET(B) receptors stimulation using a highly specific agonist, IRL-1620, to treat CNS disorders. In a rat model of cerebral ischemia intravenous administration IRL-1620 significantly reduced infarct volume and improved neurological and motor functions compared to control. This improvement, in part, is due to an increase in neuroregeneration. We also investigated the role of IRL-1620 in animal models of Alzheimer's disease (AD). IRL-1620 improved learning and memory, reduced oxidative stress and increased VEGF and NGF in Abeta treated rats. IRL-1620 also improved learning and memory in an aged APP/PS1 transgenic mouse model of AD. These promising findings prompted us to initiate human studies. Successful chemistry, manufacturing and control along with mice, rat and dog toxicological studies led to completion of a human Phase I study in healthy volunteers. We found that a dose of 0.6 microg/kg of IRL-1620 can be safely administered, three times every four hours, without any adverse effect. A Phase II clinical study with IRL-1620 has been initiated in patients with cerebral ischemia and mild to moderate AD.

Delayed Administration of BQ788, an ETB Antagonist, after Experimental Traumatic Brain Injury Promotes Recovery of Blood-Brain Barrier Function and a Reduction of Cerebral Edema in Mice

Traumatic brain injury (TBI) is induced by immediate physical disruption of brain tissue, and causes death and disability. Studies on experimental TBI animal models show that disruption of the blood-brain barrier (BBB) underlies brain edema and neuroinflammation during the delayed phase of TBI. In neurological disorders, endothelin-1 (ET-1) is involved in BBB dysfunction and brain edema. In this study, the effect of ET antagonists on BBB dysfunction and brain edema were examined in a mouse focal TBI model using lateral fluid percussion injury (FPI). ET-1 and ET_B receptors were increased at 2-7 days after FPI, which was accompanied by extravasation of Evans blue (EB) and brain edema. Repeated intracerebroventricular administration of BQ788 (15 nmol/day), an ET_B antagonist, from 2 days after FPI promoted recovery of EB extravasation and brain edema, while FR 139317, an ET_A antagonist, had no effect. Delayed intravenous administration of BQ788 also promoted recovery from FPI-induced EB extravasation and brain edema. While FPI caused decreases in claudin-5, occludin, and zonula occludens-1 proteins, BQ788 reversed FPI-induced reductions of them. Immunohistochemical observation of the cerebrum after FPI showed that ET_B receptors are predominantly expressed in glial fibrillary acidic protein (GFAP)-positive astrocytes. BQ788 reduced FPI-induced increases in GFAP-positive astrocytes. GFAP-positive astrocytes produced vascular endothelial growth factor-A (VEGF-A) and matrix metalloproteinase-9 (MMP9). FPI-induced increases in VEGF-A and MMP-9 production were reversed by BQ788. These results suggest that ET_B receptor antagonism during the delayed phase of focal TBI promotes recovery of BBB function and reduction of brain edema.

Endothelin-1 Induces Degeneration of Cultured Motor Neurons Through a Mechanism Mediated by Nitric Oxide and PI3K/Akt Pathway

Endothelin-1 (ET-1) is a vasoactive peptide produced by activated astrocytes and microglia and is implicated in initiating and sustaining reactive gliosis in neurodegenerative diseases. We have previously suggested that ET-1 can play a role in the pathophysiology of amyotrophic lateral sclerosis (ALS). Indeed, we reported that this peptide is abundantly expressed in reactive astrocytes in the spinal cord of SOD1-G93A mice and ALS patients and exerts a toxic effect on motor neurons (MNs) in an in vitro model of mixed spinal cord cultures enriched with reactive astrocytes. Here, we explored the possible mechanisms underlying the toxic effect of ET-1 on cultured MNs. We show that ET-1 toxicity is not directly caused by oxidative stress or activation of cyclooxygenase-2 but requires the synthesis of nitric oxide and is mediated by a reduced activation of the phosphoinositide 3-kinase pathway. Furthermore, we observed that ET-1 is also toxic for microglia, although its effect on MNs is independent of the presence of this type of glial cells. Our study confirms that ET-1 may contribute to MN death and corroborates the view that the modulation of ET-1 signaling might be a therapeutic strategy to slow down MN degeneration in ALS.

Gene expression profiles and protein-protein interaction networks in amyotrophic lateral sclerosis patients with C9orf72 mutation

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that involves the death of neurons. ALS is associated with many gene mutations as previously studied. In order to explore the molecular mechanisms underlying ALS with C9orf72 mutation, gene expression profiles of ALS fibroblasts and control fibroblasts were subjected to bioinformatics analysis. Genes with critical functional roles can be detected by a measure of node centrality in biological networks. In gene co-expression networks, highly connected genes called as candidate hubs have been associated with key disease-related pathways. Herein, this method was applied to find the hub genes related to ALS disease.

METHODS

Illumina HiSeq microarray gene expression dataset GSE51684 was retrieved from Gene Expression Omnibus (GEO) database which included four Sporadic ALS, twelve Familial ALS and eight control samples. Differentially Expressed Genes (DEGs) were identified using the Student's t test statistical method and gene co-expression networking. Gene ontology (GO) function and KEGG pathway enrichment analysis of DEGs were performed using the DAVID online tool. Protein-protein interaction (PPI) networks were constructed by mapping the DEGs onto protein-protein interaction data from publicly available databases to identify the pathways where DEGs are involved in. PPI interaction network was divided into subnetworks using MCODE algorithm and was analyzed using Cytoscape.

RESULTS

The results revealed that the expression of DEGs was mainly involved in cell adhesion, cell-cell signaling, Extra cellular matrix region GO processes and focal adhesion, neuroactive ligand receptor interaction, Extracellular matrix receptor interaction. Tumor necrosis factor (TNF), Endothelin 1 (EDN1), Angiotensin (AGT) and many cell adhesion molecules (CAM) were detected as hub genes that can be targeted as novel therapeutic targets for ALS disease.

CONCLUSION

These analyses and findings enhance the understanding of ALS pathogenesis and provide references for ALS therapy.

Impaired neurodevelopment by the low complexity domain of CPEB4 reveals a convergent pathway with neurodegeneration

CPEB4 is an RNA binding protein expressed in neuronal tissues including brain and spinal cord. CPEB4 has two domains: one that is structured for RNA binding and one that is unstructured and low complexity that has no known function. Unstructured low complexity domains (LCDs) in proteins are often found in RNA-binding proteins and have been implicated in motor neuron degenerative diseases such as amyotrophic lateral sclerosis, indicating that these regions mediate normal RNA processing as well as pathological events. While CPEB4 null knockout mice are normal, animals expressing only the CPEB4 LCD are neonatal lethal with impaired mobility that display defects in neuronal development such as reduced motor axon branching and abnormal neuromuscular junction formation. Although full-length CPEB4 is nearly exclusively cytoplasmic, the CPEB4 LCD forms nucleolar aggregates and CPEB4 LCD-expressing animals have altered ribosomal RNA biogenesis, ribosomal protein gene expression, and elevated levels of stress response genes such as the actin-bundling protein DRR1, which impedes neurite outgrowth. Some of these features share similarities with other LCD-related neurodegenerative disease. Most strikingly, DRR1 appears to be a common focus of several neurodevelopmental and neurodegenerative disorders. Our study reveals a possible molecular convergence between a neurodevelopmental defect and neurodegeneration mediated by LCDs.

Megacities air pollution problems: Mexico City Metropolitan Area critical issues on the central nervous system pediatric impact

The chronic health effects associated with sustained exposures to high concentrations of air pollutants are an important issue for millions of megacity residents and millions more living in smaller urban and rural areas. Particulate matter (PM) and ozone (O3) concentrations close or above their respective air quality standards during the last 20 years affect 24 million people living in the Mexico City Metropolitan Area (MCMA). Herein we discuss PM and O3 trends in MCMA and their possible association with the observed central nervous system (CNS) effects in clinically healthy children. We argue that prenatal and postnatal sustained exposures to a natural environmental exposure chamber contribute to detrimental neural responses. The emerging picture for MCMA children shows systemic inflammation, immunodysregulation at both systemic and brain levels, oxidative stress, neuroinflammation, small blood vessel pathology, and an intrathecal inflammatory process, along with the early neuropathological hallmarks for Alzheimer and Parkinson's diseases. Exposed brains are briskly responding to their harmful environment and setting the bases for structural and volumetric changes, cognitive, olfactory, auditory and vestibular deficits and long term neurodegenerative consequences. We need to improve our understanding of the PM pediatric short and long term CNS impact through multidisciplinary research. Public health benefit can be achieved by integrating interventions that reduce fine PM levels and pediatric exposures and establishing preventative screening programs targeting pediatric populations that are most at risk. We fully expect that the health of 24 million residents is important and blocking pediatric air pollution research and hiding critical information that ought to be available to our population, health, education and social workers is not in the best interest of our children.