scholarly journals Inhibition of Hsp70 suppresses neuronal hyperexcitability and attenuates seizures by enhancing A-type potassium currents

2018 ◽  
Author(s):  
Fang Hu ◽  
Jingheng Zhou ◽  
Yanxin Lu ◽  
Lizhao Guan ◽  
Ning-ning Wei ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Neuronal Excitability ◽  
Therapeutic Potential ◽  
Potassium Currents ◽  
Protective Role ◽  
Neuronal Hyperexcitability ◽  
Response To Stress ◽  
Proteosomal Degradation ◽  
Hsp70 Inhibitors

ABSTRACTThe heat shock protein 70 (Hsp70) is upregulated in response to stress and has been implicated as a stress marker in temporal lobe epilepsy (TLE). However, whether Hsp70 plays a pathologic or protective role in TLE remains unclear. Here we report that Hsp70 exerts an unexpected deleterious role in kainic acid (KA)-induced seizures, and inhibition of Hsp70 suppresses neuronal hyperexcitability and attenuates both acute and chronic seizures via enhancing A-type potassium currents primarily formed by Kv4 α-subunits and auxiliary KChIPs. Proteosomal degradation of Kv4-KChIP4a channel complexes is enhanced by Hsp70, which can be reversed by the Hsp70 inhibitors, 2-phenylethynesulfonamide (PES) and VER-155008 (VER). In cultured hippocampal neurons, either PES or VER can increase A-type Kv4 current to suppress neuronal hyperexcitability. Mechanistically, Hsp70-CHIP complexes directly bind to the N-terminus of auxiliary KChIP4a and target Kv4-KChIP4a complexes to the proteasome. Our findings reveal a previously unrecognized role of Hsp70 in mediating degradation of Kv4-KChIP4a complexes and regulating neuronal excitability, thus highlighting a therapeutic potential for hyperexcitability-related neurological disorders through Hsp70 inhibition.

Abstract P201: Negative Regulation Of PVN Pre-sympathetic Neuronal Activity By Resident Microglia

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Peng Shi ◽  
Yunfan Lin ◽  
Qianqian Bi ◽  
Guo Cheng ◽  
Xiao Shen
Keyword(s):  
Neuronal Excitability ◽  
Sympathetic Neurons ◽  
Potassium Currents ◽  
Firing Frequency ◽  
Electrophysiological Recording ◽  
Recombinant Peptide ◽  
Regulatory Circuits ◽  
Brain Parenchymal ◽  
Parenchymal Cells

Hypothalamic paraventricular nucleus (PVN) is a critical integrating region in controlling peripheral sympathetic tonicity. While the vast studies have unraveled the regulatory circuits affecting PVN pre-sympathetic neurons, local factors for maintaining the homeostasis of neuronal excitability are barely understood. In the present study we investigated the role of microglia, the primary resident immune cells of the CNS, in this context. By electrophysiological recording, we found that loss of resident microglia induced an increased firing frequency and attenuated outward potassium currents in the PVN pre-sympathetic neurons, tachycardia and impaired heart rate variability. Combining the transcriptomics analysis of the PVN microglia, we identified a releasable factor, which was dominantly expressed in microglia compared to other brain parenchymal cells. ICV infusion of the recombinant peptide restored potassium currents in the PVN pre-sympathetic neurons and autonomic function in microglia-depleted mice. In summary, our results provided a novel intrinsic regulatory mechanism by which microglia suppress neuronal over excitation in physiological condition.

scholarly journals The role of nuclear factor-erythroid 2 related factor 2 (Nrf-2) in the protection against lung injury

2017 ◽  
Vol 312 (2) ◽  
pp. L155-L162 ◽  
Author(s):  
Hailin Zhao ◽  
Shiori Eguchi ◽  
Azeem Alam ◽  
Daqing Ma
Keyword(s):  
Lung Injury ◽  
Therapeutic Potential ◽  
Antioxidant Response ◽  
Protective Role ◽  
Chronic Obstructive ◽  
Related Factor ◽  
Nuclear Factor ◽  
Obstructive Pulmonary Disease ◽  
Antioxidant Response Elements

Nuclear factor-erythroid 2 related factor 2 (Nrf2) is a ubiquitous master transcription factor that upregulates antioxidant response elements (AREs)-mediated expression of antioxidant enzyme and cytoprotective proteins. Activation of Nrf2 has been shown to be protective against lung injury. In the lung, diverse stimuli including environmental oxidants, medicinal agents, and pathogens can activate Nrf2. Nrf2 translocates to the nucleus and binds to an ARE. Through transcriptional induction of ARE-bearing genes encoding antioxidant-detoxifying proteins, Nrf2 induces cellular rescue pathways against oxidative pulmonary injury, abnormal inflammatory and immune responses, and apoptosis. The Nrf2-antioxidant pathway has been shown to be important in the protection against various lung injuries including acute lung injury/acute respiratory distress syndrome and bronchopulmonary dysplasia, chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, asthma, and allergy and was widely examined for new therapeutic targets. The present review explores the protective role of Nrf-2 against lung injury and the therapeutic potential in targeting Nrf-2.

scholarly journals Mending a broken heart: the role of mitophagy in cardioprotection

2015 ◽  
Vol 308 (3) ◽  
pp. H183-H192 ◽  
Author(s):  
Alexandra G. Moyzis ◽  
Junichi Sadoshima ◽  
Åsa B. Gustafsson
Keyword(s):  
Heart Failure ◽  
Therapeutic Potential ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Cellular Processes ◽  
Differentiated Cells ◽  
Calcium Storage ◽  
Response To Stress ◽  
Metabolite Synthesis ◽  
Energy Dependent

The heart is highly energy dependent with most of its energy provided by mitochondrial oxidative phosphorylation. Mitochondria also play a role in many other essential cellular processes including metabolite synthesis and calcium storage. Therefore, maintaining a functional population of mitochondria is critical for cardiac function. Efficient degradation and replacement of dysfunctional mitochondria ensures cell survival, particularly in terminally differentiated cells such as cardiac myocytes. Mitochondria are eliminated via mitochondrial autophagy or mitophagy. In the heart, mitophagy is an essential housekeeping process and required for cardiac homeostasis. Reduced autophagy and accumulation of impaired mitochondria have been linked to progression of heart failure and aging. In this review, we discuss the pathways that regulate mitophagy in cells and highlight the cardioprotective role of mitophagy in response to stress and aging. We also discuss the therapeutic potential of targeting mitophagy and directions for future investigation.

scholarly journals PTX3 Regulation of Inflammation, Hemostatic Response, Tissue Repair, and Resolution of Fibrosis Favors a Role in Limiting Idiopathic Pulmonary Fibrosis

2021 ◽  
Vol 12 ◽  
Author(s):  
Andrea Doni ◽  
Alberto Mantovani ◽  
Barbara Bottazzi ◽  
Remo Castro Russo
Keyword(s):  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Lung Fibrosis ◽  
Tissue Repair ◽  
Therapeutic Potential ◽  
Tissue Injury ◽  
Life Quality ◽  
Unknown Origin ◽  
Protective Role

PTX3 is a soluble pattern recognition molecule (PRM) belonging to the humoral innate immune system, rapidly produced at inflammatory sites by phagocytes and stromal cells in response to infection or tissue injury. PTX3 interacts with microbial moieties and selected pathogens, with molecules of the complement and hemostatic systems, and with extracellular matrix (ECM) components. In wound sites, PTX3 interacts with fibrin and plasminogen and favors a timely removal of fibrin-rich ECM for an efficient tissue repair. Idiopathic Pulmonary Fibrosis (IPF) is a chronic and progressive interstitial lung disease of unknown origin, associated with excessive ECM deposition affecting tissue architecture, with irreversible loss of lung function and impact on the patient’s life quality. Maccarinelli et al. recently demonstrated a protective role of PTX3 using the bleomycin (BLM)-induced experimental model of lung fibrosis, in line with the reported role of PTX3 in tissue repair. However, the mechanisms and therapeutic potential of PTX3 in IPF remained to be investigated. Herein, we provide new insights on the possible role of PTX3 in the development of IPF and BLM-induced lung fibrosis. In mice, PTX3-deficiency was associated with worsening of the disease and with impaired fibrin removal and subsequently increased collagen deposition. In IPF patients, microarray data indicated a down-regulation of PTX3 expression, thus suggesting a potential rational underlying the development of disease. Therefore, we provide new insights for considering PTX3 as a possible target molecule underlying therapeutic intervention in IPF.

scholarly journals Up-Regulation of A-Type Potassium Currents Protects Neurons Against Cerebral Ischemia

2011 ◽  
Vol 31 (9) ◽  
pp. 1823-1835 ◽  
Author(s):  
Ping Deng ◽  
Zhi-Ping Pang ◽  
Zhigang Lei ◽  
Sojin Shikano ◽  
Qiaojie Xiong ◽  
...  
Keyword(s):  
Neuronal Excitability ◽  
Recombinant Expression ◽  
Potassium Currents ◽  
Protective Role ◽  
Pathological Process ◽  
Voltage Dependent ◽  
Protein Kinase Cα ◽  
Excitotoxic Cell Death

Excitotoxicity is the major cause of many neurologic disorders including stroke. Potassium currents modulate neuronal excitability and therefore influence the pathological process. A-type potassium current ( IA) is one of the major voltage-dependent potassium currents, yet its roles in excitotoxic cell death are not well understood. We report that, following ischemic insults, the IA increases significantly in large aspiny (LA) neurons but not medium spiny (MS) neurons in the striatum, which correlates with the higher resistance of LA neurons to ischemia. Activation of protein kinase Cα increases IA in LA neurons after ischemia. Cultured neurons from transgenic mice lacking both Kv1.4 and Kv4.2 subunits exhibit an increased vulnerability to ischemic insults. Increase of IA by recombinant expression of Kv1.4 or Kv4.2 is sufficient in improving the survival of MS neurons against ischemic insults both in vitro and in vivo. These results, taken together, provide compelling evidence for a protective role of IA against ischemia.

scholarly journals Getting to NO Alzheimer’s Disease: Neuroprotection versus Neurotoxicity Mediated by Nitric Oxide

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Rachelle Balez ◽  
Lezanne Ooi
Keyword(s):  
Nitric Oxide ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Signaling Pathways ◽  
Neuronal Excitability ◽  
Neurodegenerative Disorder ◽  
Memory Loss ◽  
Protective Role ◽  
Ionic Mechanisms

Alzheimer’s disease (AD) is a neurodegenerative disorder involving the loss of neurons in the brain which leads to progressive memory loss and behavioral changes. To date, there are only limited medications for AD and no known cure. Nitric oxide (NO) has long been considered part of the neurotoxic insult caused by neuroinflammation in the Alzheimer’s brain. However, focusing on early developments, prior to the appearance of cognitive symptoms, is changing that perception. This has highlighted a compensatory, neuroprotective role for NO that protects synapses by increasing neuronal excitability. A potential mechanism for augmentation of excitability by NO is via modulation of voltage-gated potassium channel activity (Kv7 and Kv2). Identification of the ionic mechanisms and signaling pathways that mediate this protection is an important next step for the field. Harnessing the protective role of NO and related signaling pathways could provide a therapeutic avenue that prevents synapse loss early in disease.

scholarly journals Recent Advances on the Role and Therapeutic Potential of Regulatory T Cells in Atherosclerosis

2021 ◽  
Vol 10 (24) ◽  
pp. 5907
Author(s):  
Toru Tanaka ◽  
Naoto Sasaki ◽  
Yoshiyuki Rikitake
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Therapeutic Potential ◽  
Vascular Inflammation ◽  
Immunological Tolerance ◽  
Protective Role ◽  
Atherosclerotic Cardiovascular Disease ◽  
Recent Advances

Atherosclerotic diseases, including ischemic heart disease and stroke, are a main cause of mortality worldwide. Chronic vascular inflammation via immune dysregulation is critically involved in the pathogenesis of atherosclerosis. Accumulating evidence suggests that regulatory T cells (Tregs), responsible for maintaining immunological tolerance and suppressing excessive immune responses, play an important role in preventing the development and progression of atherosclerosis through the regulation of pathogenic immunoinflammatory responses. Several strategies to prevent and treat atherosclerosis through the promotion of regulatory immune responses have been developed, and could be clinically applied for the treatment of atherosclerotic cardiovascular disease. In this review, we summarize recent advances in our understanding of the protective role of Tregs in atherosclerosis and discuss attractive approaches to treat atherosclerotic disease by augmenting regulatory immune responses.

scholarly journals Human Surfactant Protein D Binds Spike Protein and Acts as an Entry Inhibitor of SARS-CoV-2 Pseudotyped Viral Particles

2021 ◽  
Vol 12 ◽  
Author(s):  
Miao-Hsi Hsieh ◽  
Nazar Beirag ◽  
Valarmathy Murugaiah ◽  
Yu-Chi Chou ◽  
Wen-Shuo Kuo ◽  
...  
Keyword(s):  
Influenza A ◽  
Therapeutic Potential ◽  
Ex Vivo ◽  
Protective Role ◽  
Spike Protein ◽  
Entry Inhibitor ◽  
Surfactant Protein D ◽  
Viral Inhibition ◽  
Immune Molecule

Human SP-D is a potent innate immune molecule whose presence at pulmonary mucosal surfaces allows its role in immune surveillance against pathogens. Higher levels of serum SP-D have been reported in the patients with severe acute respiratory syndrome coronavirus (SARS-CoV). Studies have suggested the ability of human SP-D to recognise spike glycoprotein of SARS-CoV; its interaction with HCoV-229E strain leads to viral inhibition in human bronchial epithelial (16HBE) cells. Previous studies have reported that a recombinant fragment of human SP-D (rfhSP-D) composed of 8 Gly-X-Y repeats, neck and CRD region, can act against a range of viral pathogens including influenza A Virus and Respiratory Syncytial Virus in vitro, in vivo and ex vivo. In this context, this study was aimed at examining the likely protective role of rfhSP-D against SARS-CoV-2 infection. rfhSP-D showed a dose-responsive binding to S1 spike protein of SARS-CoV-2 and its receptor binding domain. Importantly, rfhSP-D inhibited interaction of S1 protein with the HEK293T cells overexpressing human angiotensin converting enzyme 2 (hACE2). The protective role of rfhSP-D against SARS-CoV-2 infection as an entry inhibitor was further validated by the use of pseudotyped lentiviral particles expressing SARS-CoV-2 S1 protein; ~0.5 RLU fold reduction in viral entry was seen following treatment with rfhSP-D (10 µg/ml). These results highlight the therapeutic potential of rfhSP-D in SARS-CoV-2 infection and merit pre-clinical studies in animal models.

Abstract 150: S-nitrosylation Of Thioredoxin1 At Cysteine 73 Promotes Trans-nitrosylation, Autophagy And Cell Survival During Glucose Deprivation.

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Narayani Nagarajan ◽  
Sebastiano Sciarretta ◽  
Junichi Sadoshima
Keyword(s):  
Cell Survival ◽  
Protein S ◽  
Glucose Deprivation ◽  
Protective Role ◽  
Redox Activity ◽  
Oxidoreductase Activity ◽  
Response To Stress ◽  
Thioredoxin 1 ◽  
Biotin Switch

Thioredoxin-1 (Trx1) is a key antioxidant protein that is known to play a protective role in the heart during oxidative stress mainly through its oxidoreductase activity. Trx1 can be S-nitrosylated and, in turn, can trans-nitrosylate other proteins. However, the role of Trx1-dependent S-nitrosylation in cardiomyocytes (CMs) is not known. Here, we investigated the role of Trx1-mediated protein S-nitrosylation in the regulation of CM survival in response to stress. Using the biotin-switch assay, we found that wild-type Trx1 (Trx1WT) was S-nitrosylated, whereas the extent of S-nitrosylation was attenuated in Trx1C73S, suggesting that Trx1 is S-nitrosylated at Cys73. Also, we observed that the redox activity of Trx1 was intact in the Trx1C73S mutant. Overall protein S-nitrosylation in rat neonatal CMs was increased in response to 4 hrs of glucose deprivation (GD). Using biotin-switch assay and immunocytochemistry (fluorescent staining of s-nitrosylated cysteines), we observed that overexpression of Trx1WT increased, whereas short-hairpin RNA-mediated knockdown of Trx1 (shTrx1) or overexpression of Trx1C73S decreased, total protein S-nitrosylation in response to GD. These results suggest that Trx1Cys73 plays a key role in the regulation of protein S-nitrosylation in CMs during GD. Overexpression of Trx1 increased CM survival after 24 hrs of GD (Trx1WT vs. LacZ: propidium iodide assay, 0.5 ± 0.08-fold, p<0.01). Conversely, shTrx1 or overexpression of Trx1C73S increased cell death during GD (Trx1C73S vs. LacZ: 1.7 ± 0.034-fold, p<0.05). Autophagy is a pro-survival mechanism during GD. Therefore, we tested the effect of Trx1 on autophagy. After 4 hrs of GD, knockdown of Trx1 or overexpression of Trx1C73S decreased autophagy compared to control cells (LC3-II/LC3-I, 0.7-fold; autophagosomes, 0.83 ± 0.16-fold; autolysosomes, 0.62 ± 0.13-fold, p<0.005). Taken altogether, our results suggest that Trx1 promotes autophagy during GD through a trans-nitrosylation dependent mechanism. S-nitrosylation of Trx1 at Cys73 is associated with an overall increase in protein S-nitrosylation in CMs and promotes autophagy and thus, cell survival during GD.

Sign in / Sign up

Export Citation Format

Share Document