Rho/ROCK Pathway and Noncoding RNAs: Implications in Ischemic Stroke and Spinal Cord Injury

From single to combinatorial therapies in spinal cord injuries for structural and functional restoration

Spinal cord injury results in paralysis, sensory disturbances, sphincter dysfunction, and multiple systemic secondary conditions, most arising from autonomic dysregulation. All this produces profound negative psychosocial implications for affected people, their families, and their communities; the financial costs can be challenging for their families and health institutions. Treatments aimed at restoring the spinal cord after spinal cord injury, which have been tested in animal models or clinical trials, generally seek to counteract one or more of the secondary mechanisms of injury to limit the extent of the initial damage. Most published works on structural/functional restoration in acute and chronic spinal cord injury stages use a single type of treatment: a drug or trophic factor, transplant of a cell type, and implantation of a biomaterial. Despite the significant benefits reported in animal models, when translating these successful therapeutic strategies to humans, the result in clinical trials has been considered of little relevance because the improvement, when present, is usually insufficient. Until now, most studies designed to promote neuroprotection or regeneration at different stages after spinal cord injury have used single treatments. Considering the occurrence of various secondary mechanisms of injury in the acute and sub-acute phases of spinal cord injury, it is reasonable to speculate that more than one therapeutic agent could be required to promote structural and functional restoration of the damaged spinal cord. Treatments that combine several therapeutic agents, targeting different mechanisms of injury, which, when used as a single therapy, have shown some benefits, allow us to assume that they will have synergistic beneficial effects. Thus, this narrative review article aims to summarize current trends in the use of strategies that combine therapeutic agents administered simultaneously or sequentially, seeking structural and functional restoration of the injured spinal cord.

Proteomics Analysis of Proteotoxic Stress Response in In-Vitro Human Neuronal Models

Heat stroke, a hazardous hyperthermia-related illness, is characterized by CNS injury, particularly long-lasting brain damage. A root cause for hyperthermic neurological damage is heat-induced proteotoxic stress through protein aggregation, a known causative agent of neurological disorders. Stress magnitude and enduring persistence are highly correlated with hyperthermia-associated neurological damage. We used an untargeted proteomic approach using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify and characterize time-series proteome-wide changes in dose-responsive proteotoxic stress models in medulloblastoma [Daoy], neuroblastoma [SH-SY5Y], and differentiated SH-SY5Y neuron-like cells [SH(D)]. An integrated analysis of condition-time datasets identified global proteome-wide differentially expressed proteins (DEPs) as part of the heat-induced proteotoxic stress response. The condition-specific analysis detected higher DEPs and upregulated proteins in extreme heat stress with a relatively conservative and tight regulation in differentiated SH-SY5Y neuron-like cells. Functional network analysis using ingenuity pathway analysis (IPA) identified common intercellular pathways associated with the biological processes of protein, RNA, and amino acid metabolism and cellular response to stress and membrane trafficking. The condition-wise temporal pathway analysis in the differentiated neuron-like cells detects a significant pathway, functional, and disease association of DEPs with processes like protein folding and protein synthesis, Nervous System Development and Function, and Neurological Disease. An elaborate dose-dependent stress-specific and neuroprotective cellular signaling cascade is also significantly activated. Thus, our study provides a comprehensive map of the heat-induced proteotoxic stress response associating proteome-wide changes with altered biological processes. This helps to expand our understanding of the molecular basis of the heat-induced proteotoxic stress response with potential translational connotations.

The Roles of RhoA/ROCK/NF-κB Pathway in Microglia Polarization Following Ischemic Stroke

Ischemic stroke is the leading cause of death and disability worldwide. Nevertheless, there still lacks the effective therapies for ischemic stroke. Microglia are resident macrophages of the central nervous system (CNS) and can initiate immune responses and monitor the microenvironment. Microglia are activated and polarize into proinflammatory or anti‑inflammatory phenotype in response to various brain injuries, including ischemic stroke. Proinflammatory microglia could generate immunomodulatory mediators, containing cytokines and chemokines, these mediators are closely associated with secondary brain damage following ischemic stroke. On the contrary, anti-inflammatory microglia facilitate recovery following stroke. Regulating the activation and the function of microglia is crucial in exploring the novel treatments for ischemic stroke patients. Accumulating studies have revealed that RhoA/ROCK pathway and NF-κB are famous modulators in the process of microglia activation and polarization. Inhibiting these key modulators can promote the polarization of microglia to anti-inflammatory phenotype. In this review, we aimed to provide a comprehensive overview on the role of RhoA/ROCK pathway and NF-κB in the microglia activation and polarization, reveal the relationship between RhoA/ROCK pathway and NF-κB in the pathological process of ischemic stroke. In addition, we likewise discussed the drug modulators targeting microglia polarization.

Rhoa/ROCK, mTOR and Secretome-Based Treatments for Ischemic Stroke: New Perspectives

Ischemic stroke triggers a complex cascade of cellular and molecular events leading to neuronal damage and tissue injury. This review explores the potential therapeutic avenues targeting cellular signaling pathways implicated in stroke pathophysiology. Specifically, it focuses on the articles that highlight the roles of RhoA/ROCK and mTOR signaling pathways in ischemic brain injury and their therapeutic implications. The RhoA/ROCK pathway modulates various cellular processes, including cytoskeletal dynamics and inflammation, while mTOR signaling regulates cell growth, proliferation, and autophagy. Preclinical studies have demonstrated the neuroprotective effects of targeting these pathways in stroke models, offering insights into potential treatment strategies. However, challenges such as off-target effects and the need for tissue-specific targeting remain. Furthermore, emerging evidence suggests the therapeutic potential of MSC secretome in stroke treatment, highlighting the importance of exploring alternative approaches. Future research directions include elucidating the precise mechanisms of action, optimizing treatment protocols, and translating preclinical findings into clinical practice for improved stroke outcomes.

Mechanism Study of Polydatin in Treating Spinal Cord Injury by Modulating Mitochondrial Membrane Potential Based on Network Pharmacology and Molecular Docking

Spinal cord injury (SCI) is one of the most devastating central lesions, and mitochondrial function plays an important role in secondary injury after SCI. Polydatin (PD) is a natural glycosylated precursor of resveratrol, showing mitochondrial preservation effects in the central nervous system. This study aimed to identify the hub target genes of PD on mitochondrial membrane potential (MMP) in SCI. A comprehensive analysis was performed on SCI-related genes, MMP-related genes, and PD targets screening from public databases. Differential expression analysis was conducted to identify differentially expressed genes (DEGs) in SCI. Gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) were employed to assess pathway enrichment. Protein-protein interaction (PPI) network analysis and molecular docking were conducted to identify key genes and evaluate the binding affinity between PD and hub genes. A total of 16,958 SCI-related genes, 2,786 MMP-related genes, 318 PD-related target genes, and 7229 DEGs were identified. Intersection analysis revealed 46 genes common to all four categories. GSEA and GSVA analysis identified significant enrichment of pathways associated with suppressed and activated SCI biological processes. The PPI network analysis identified seven core hub genes: EGFR, SRC, VEGFA, STAT3, ERBB2, TP53, and RHOA. Molecular docking revealed strong binding affinities between PD and ERBB2, EGFR, and RHOA. The findings based on computational investigation from public databases suggest that PD may have therapeutic potential for SCI by modulating MMP. These results contribute to the understanding of SCI pathogenesis and the development of novel therapeutic strategies.

Axonal growth inhibitors and their receptors in spinal cord injury: from biology to clinical translation

Axonal growth inhibitors are released during traumatic injuries to the adult mammalian central nervous system, including after spinal cord injury. These molecules accumulate at the injury site and form a highly inhibitory environment for axonal regeneration. Among these inhibitory molecules, myelin-associated inhibitors, including neurite outgrowth inhibitor A, oligodendrocyte myelin glycoprotein, myelin-associated glycoprotein, chondroitin sulfate proteoglycans and repulsive guidance molecule A are of particular importance. Due to their inhibitory nature, they represent exciting molecular targets to study axonal inhibition and regeneration after central injuries. These molecules are mainly produced by neurons, oligodendrocytes, and astrocytes within the scar and in its immediate vicinity. They exert their effects by binding to specific receptors, localized in the membranes of neurons. Receptors for these inhibitory cues include Nogo receptor 1, leucine-rich repeat, and Ig domain containing 1 and p75 neurotrophin receptor/tumor necrosis factor receptor superfamily member 19 (that form a receptor complex that binds all myelin-associated inhibitors), and also paired immunoglobulin-like receptor B. Chondroitin sulfate proteoglycans and repulsive guidance molecule A bind to Nogo receptor 1, Nogo receptor 3, receptor protein tyrosine phosphatase σ and leucocyte common antigen related phosphatase, and neogenin, respectively. Once activated, these receptors initiate downstream signaling pathways, the most common amongst them being the RhoA/ROCK signaling pathway. These signaling cascades result in actin depolymerization, neurite outgrowth inhibition, and failure to regenerate after spinal cord injury. Currently, there are no approved pharmacological treatments to overcome spinal cord injuries other than physical rehabilitation and management of the array of symptoms brought on by spinal cord injuries. However, several novel therapies aiming to modulate these inhibitory proteins and/or their receptors are under investigation in ongoing clinical trials. Investigation has also been demonstrating that combinatorial therapies of growth inhibitors with other therapies, such as growth factors or stem-cell therapies, produce stronger results and their potential application in the clinics opens new venues in spinal cord injury treatment.

CircFKBP3 absence alleviates oxygen glucose deprivation-induced function loss of human brain microvascular endothelial cells in vitro via governing the miR-766-3p/TRAF3 axis

BACKGROUND

Brain microvascular endothelial cell (BMEC) functions loss is a key event in the development of ischemic stroke, which may be affected by the dysregulation of circular RNAs (circRNAs). We aimed to unveil the role of circRNA FKBP Prolyl Isomerase 3 (circFKBP3) in cell models of ischemic stroke.

METHODS

Cell models of ischemic stroke were constructed in human BEMCs (HBMECs) with the treatment of oxygen glucose deprivation (OGD). Quantitative real-time PCR (qPCR) and western blotting were conducted for expression analysis of circFKBP3, miR-766-3p and TNF receptor associated factor 3 (TRAF3). CCK-8, transwell, wound healing, flow cytometry, tube formation and ELISA assays were implemented to monitor cell viability, migration, apoptosis, angiogenesis and inflammation production. The putative binding relationship between miR-766-3p and circFKBP3 or TRAF3 was validated by dual-luciferase, RIP and pull-down assays.

RESULTS

CircFKBP3 expression was elevated in OGD-treated HBMECs. OGD suppressed HBMEC viability, migration, angiogenesis, and provoked cell apoptosis and inflammation production, while knockdown of circFKBP3 attenuated these effects. CircFKBP3 interacted with miR-766-3p, and circFKBP3 absence-repressed HBMEC function loss and inflammation were recovered by miR-766-3p inhibition. CircFKBP3 targeted miR-766-3p to regulate TRAF3 expression. MiR-766-3p enrichment-repressed HBMEC function loss and inflammation were recovered by TRAF3 overexpression.

CONCLUSION

CircFKBP3 absence alleviated OGD-induced function loss and inflammatory responses of HBMECs via governing the miR-766-3p/TRAF3 axis.

Building a pathway to recovery: Targeting ECM remodeling in CNS injuries

Extracellular matrix (ECM) is a complex and dynamic network of proteoglycans, proteins, and other macromolecules that surrounds cells in tissues. The ECM provides structural support to cells and plays a critical role in regulating various cellular functions. ECM remodeling is a dynamic process involving the breakdown and reconstruction of the ECM. This process occurs naturally during tissue growth, wound healing, and tissue repair. However, in the context of central nervous system (CNS) injuries, dysregulated ECM remodeling can lead to the formation of fibrotic and glial scars. CNS injuries encompass various traumatic events, including concussions and fractures. Following CNS trauma, the formation of glial and fibrotic scars becomes prominent. Glial scars primarily consist of reactive astrocytes, while fibrotic scars are characterized by an abundance of ECM proteins. ECM remodeling plays a pivotal and tightly regulated role in the development of these scars after spinal cord and brain injuries. Various factors like ECM components, ECM remodeling enzymes, cell surface receptors of ECM molecules, and downstream pathways of ECM molecules are responsible for the remodeling of the ECM. The aim of this review article is to explore the changes in ECM during normal physiological conditions and following CNS injuries. Additionally, we discuss various approaches that target various factors responsible for ECM remodeling, with a focus on promoting axon regeneration and functional recovery after CNS injuries. By targeting ECM remodeling, it may be possible to enhance axonal regeneration and facilitate functional recovery after CNS injuries.

Inflammatory signaling pathways in the treatment of Alzheimer's disease with inhibitors, natural products and metabolites (Review)

The intricate nature of Alzheimer's disease (AD) pathogenesis poses a persistent obstacle to drug development. In recent times, neuroinflammation has emerged as a crucial pathogenic mechanism of AD, and the targeting of inflammation has become a viable approach for the prevention and management of AD. The present study conducted a comprehensive review of the literature between October 2012 and October 2022, identifying a total of 96 references, encompassing 91 distinct pharmaceuticals that have been investigated for their potential impact on AD by inhibiting neuroinflammation. Research has shown that pharmaceuticals have the potential to ameliorate AD by reducing neuroinflammation mainly through regulating inflammatory signaling pathways such as NF‑κB, MAPK, NLRP3, PPARs, STAT3, CREB, PI3K/Akt, Nrf2 and their respective signaling pathways. Among them, tanshinone IIA has been extensively studied for its anti‑inflammatory effects, which have shown significant pharmacological properties and can be applied clinically. Thus, it may hold promise as an effective drug for the treatment of AD. The present review elucidated the inflammatory signaling pathways of pharmaceuticals that have been investigated for their therapeutic efficacy in AD and elucidates their underlying mechanisms. This underscores the auspicious potential of pharmaceuticals in ameliorating AD by impeding neuroinflammation.

Longitudinal multiparametric MRI of traumatic spinal cord injury in animal models

Multi-parametric MRI (mpMRI) technology enables non-invasive and quantitative assessments of the structural, molecular, and functional characteristics of various neurological diseases. Despite the recognized importance of studying spinal cord pathology, mpMRI applications in spinal cord research have been somewhat limited, partly due to technical challenges associated with spine imaging. However, advances in imaging techniques and improved image quality now allow longitudinal investigations of a comprehensive range of spinal cord pathological features by exploiting different endogenous MRI contrasts. This review summarizes the use of mpMRI techniques including blood oxygenation level-dependent (BOLD) functional MRI (fMRI), diffusion tensor imaging (DTI), quantitative magnetization transfer (qMT), and chemical exchange saturation transfer (CEST) MRI in monitoring different aspects of spinal cord pathology. These aspects include cyst formation and axonal disruption, demyelination and remyelination, changes in the excitability of spinal grey matter and the integrity of intrinsic functional circuits, and non-specific molecular changes associated with secondary injury and neuroinflammation. These approaches are illustrated with reference to a nonhuman primate (NHP) model of traumatic cervical spinal cord injuries (SCI). We highlight the benefits of using NHP SCI models to guide future studies of human spinal cord pathology, and demonstrate how mpMRI can capture distinctive features of spinal cord pathology that were previously inaccessible. Furthermore, the development of mechanism-based MRI biomarkers from mpMRI studies can provide clinically useful imaging indices for understanding the mechanisms by which injured spinal cords progress and repair. These biomarkers can assist in the diagnosis, prognosis, and evaluation of therapies for SCI patients, potentially leading to improved outcomes.

The role of RhoA/ROCK pathway in the ischemic stroke-induced neuroinflammation

It is widely known that ischemic stroke is the prominent cause of death and disability. To date, neuroinflammation following ischemic stroke represents a complex event, which is an essential process and affects the prognosis of both experimental stroke animals and stroke patients. Intense neuroinflammation occurring during the acute phase of stroke contributes to neuronal injury, BBB breakdown, and worse neurological outcomes. Inhibition of neuroinflammation may be a promising target in the development of new therapeutic strategies. RhoA is a small GTPase protein that activates a downstream effector, ROCK. The up-regulation of RhoA/ROCK pathway possesses important roles in promoting the neuroinflammation and mediating brain injury. In addition, nuclear factor-kappa B (NF-κB) is another vital regulator of ischemic stroke-induced neuroinflammation through regulating the functions of microglial cells and astrocytes. After stroke onset, the microglial cells and astrocytes are activated and undergo the morphological and functional changes, thereby deeply participate in a complicated neuroinflammation cascade. In this review, we focused on the relationship among RhoA/ROCK pathway, NF-κB and glial cells in the neuroinflammation following ischemic stroke to reveal new strategies for preventing the intense neuroinflammation.

Mechanistic Study for Drug Induced Cholestasis Using Batch-Fabricated 3D Spheroids Developed by Agarose-Stamping Method

Cell spheroid culture can recapitulate the tissue microstructure and cellular responses in vivo. While there is a strong need to understand the modes of toxic action using the spheroid culture method, existing preparation techniques suffer from low efficiency and high cost. Herein, we developed a metal stamp containing hundreds of protrusions for batch bulk preparation of cell spheroids in each well of the culture plates. The agarose matrix imprinted by the stamp can form an array of hemispherical pits, which facilitated the fabrication of hundreds of uniformly sized rat hepatocyte spheroids in each well. Chlorpromazine (CPZ) was used as a model drug to investigate the mechanism for drug induced cholestasis (DIC) by agarose-stamping method. Hepatocyte spheroids showed a more sensitive detection of hepatotoxicity compared to 2D and Matrigel-based culture systems. Cell spheroids were also collected for staining of cholestatic protein and showed a CPZ-concentration-dependent decrease of bile acid efflux related proteins (BSEP and MRP2) and tight junction (ZO-1). In addition, the stamping system successfully delineated the DIC mechanism by CPZ that may be associated with the phosphorylation of MYPT1 and MLC2, two central proteins in the Rho-associated protein kinase pathway (ROCK), which were significantly attenuated by ROCK inhibitors. Our results demonstrated a large-scale fabrication of cell spheroids by the agarose-stamping method, with promising benefits for exploring the mechanisms for drug hepatotoxic responses.

A focus on Rho/ROCK signaling pathway: An emerging therapeutic target in depression

Depression is the most common mental health disorder worldwide; however, the exact cellular and molecular mechanisms of this major depressive disorder are unclear so far. Experimental studies have demonstrated that depression is associated with significant cognitive impairment, dendrite spine loss, and reduction in connectivity among neurons that contribute to symptoms associated with mood disorders. Rho/Rho-associated coiled-coil containing protein kinase (ROCK) receptors are exclusively expressed in the brain and Rho/ROCK signaling has gained considerable attention as it plays a crucial role in the development of neuronal architecture and structural plasticity. Chronic stress-induced activation of the Rho/ROCK signaling pathway promotes neuronal apoptosis and loss of neural processes and synapses. Interestingly, accumulated evidence has identified Rho/ROCK signaling pathways as a putative target for treating neurological disorders. Furthermore, inhibition of the Rho/ROCK signaling pathway has proven to be effective in different models of depression, which signify the potential benefits of clinical Rho/ROCK inhibition. The ROCK inhibitors extensively modulate antidepressant-related pathways which significantly control the synthesis of proteins, and neuron survival and ultimately led to the enhancement of synaptogenesis, connectivity, and improvement in behavior. Therefore, the present review refines the prevailing contribution of this signaling pathway in depression and highlighted preclinical shreds of evidence for employing ROCK inhibitors as disease-modifying targets along with possible underlying mechanisms in stress-associated depression.

CDC42 Might Be a Molecular Signature of DWI-FLAIR Mismatch in a Nonhuman Primate Stroke Model

No definitive blood markers of DWI-FLAIR mismatch, a pivotal indicator of salvageable ischemic penumbra brain tissue, are known. We previously reported that CDC42 and RHOA are associated with the ischemic penumbra. Here, we investigated whether plasma CDC42 and RHOA are surrogate markers of DWI-FLAIR mismatch. Sixteen cynomolgus macaques (3 as controls and 13 for the stroke model) were included. Guided by digital subtraction angiography (DSA), a middle cerebral artery occlusion (MCAO) model was established by occluding the middle cerebral artery (MCA) with a balloon. MRI and neurological deficit scoring were performed to evaluate postinfarction changes. Plasma CDC42 and RHOA levels were measured by enzyme-linked immunosorbent assay (ELISA). The stroke model was successfully established in eight monkeys. Based on postinfarction MRI images, experimental animals were divided into a FLAIR (-) group (N = 4) and a FLAIR (+) group (N = 4). Plasma CDC42 in the FLAIR (-) group showed a significant decrease compared with that in the FLAIR (+) group (p < 0.05). No statistically significant difference was observed for plasma RHOA. The FLAIR (-) group showed a milder neurological function deficit and a smaller infarct volume than the FLAIR (+) group (p < 0.05). Therefore, plasma CDC42 might be a new surrogate marker for DWI-FLAIR mismatch.

Exploring the mechanism of Chaihujia Longgu Muli decoction in the treatment of epilepsy in rats based on the RhoA/ROCK signaling pathway

BACKGROUND

The Chinese herbal formula Chaihujia Longgu Muli Decoction (CD) has a good antiepileptic effect, but its mechanisms remain unclear. Therefore, in this study we explored the molecular mechanisms of CD against epilepsy.

METHODS

Twelve-day-old SD rats were randomly divided into a normal group, model group, valproic acid group, and CD high, medium, and low groups. Except for the normal group, the other groups were given an intraperitoneal injection of pentylenetetrazol (PTZ) to establish epilepsy models, and the Racine score was applied for model judgment. After 14 consecutive days of dosing, the Morris water maze test was performed. Then, hippocampal Nissl staining and immunofluorescence staining were performed, and synaptic ultrastructure was observed by transmission electron microscopy (TEM). RhoA/ROCK signaling pathway proteins were detected.

RESULTS

In PTZ model rats, the passing times were reduced, and the escape latency was prolonged in the Morris water maze test. Nissl staining showed that some hippocampal neurons swelled and ruptured, Nissl bodies in the cytoplasm were significantly reduced, and neurons were lost. Immunofluorescence detection revealed that the expression of PSD95 and SYP was significantly reduced. Electron microscopy results revealed that the number of synapses in hippocampal neurons was significantly reduced and the postsynaptic membrane length was significantly reduced. Western blot analysis showed that the RhoA/ROCK signaling pathway was activated, while SYP, SPD95, and PTEN expression was significantly decreased. After treatment with CD, neurobehavioral abnormalities and neuronal damage caused by epileptic seizures were improved.

CONCLUSION

CD exerted an antiepileptic effect by inhibiting the activation of the RhoA/ROCK signaling pathway.

Protection of H2S against Hypoxia/Reoxygenation Injury in Rat Hippocampal Neurons through Inhibiting Phosphorylation of ROCK2 at Thr436 and Ser575

BACKGROUND

H2S (hydrogen sulfide) protects cerebral vasodilatation and endothelial cells against oxygen-glucose deprivation/reoxygenation injury via the inhibition of the RhoA-ROCK pathway and ROCK2 expression. However, the inhibitory mechanism of H2S on ROCK2 expression is still unclear. The study aimed to investigate the target and mechanism of H2S in inhibition of ROCK2.

METHODS

His-ROCK2wild protein was constructed, expressed, and was used for phosphorylation assay in vitro. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to determine the potential phosphorylation sites of ROCK2. Recombinant ROCK2wild-pEGFP-N1, ROCK2T436A-pEGFP-N1, and ROCK2S575F-pEGFP-N1 plasmids were constructed and transfected into rat hippocampal neurons (RHNs). ROCK2 expression, cell viability, the release of lactate dehydrogenase (LDH), nerve-specific enolase (NSE), and Ca2+ were detected to evaluate the neuroprotective mechanism of H2S.

RESULTS

Phosphorylation at Thr436 and Ser575 of ROCK2 was observed by mass spectrometry when Polo-like kinase 1 (PLK1) and protein kinase A (PKA) were added in vitro, and NaHS significantly inhibited phosphorylation at Thr436 and Ser575. Additionally, NaHS significantly inhibited the expression of ROCK2 and recombinant proteins GFP-ROCK2, GFP-ROCK2T436A, and GFP-ROCK2S575F in transfected RHNs. Compared with empty plasmid, GFP-ROCK2T436A, and GFP-ROCK2S575F groups, NaHS significantly inhibited the release of LDH, NSE, and Ca2+ and promoted ROCK2 activity in the GFP-ROCK2wild group. Thr436 and Ser575 may be dominant sites that mediate NaHS inhibition of ROCK2 protein activity in RHNs. Compared with the empty plasmid, GFP-ROCK2T436A, and the GFP-ROCK2S575F group, NaHS had more significant inhibitory effects on hypoxia/reoxygenation (H/R) injury-induced cell viability reduction and increased LDH and NSE release in the GFP-ROCK2wild group.

CONCLUSION

Exogenous H2S protected the RHNs against H/R injury via Thr436 and Ser575 of ROCK2. These findings suggested that Thr436 and Ser575 may be the dominant sites that mediated the effect of NaHS on protecting RHNs against H/R injury.

H2S-mediated inhibition of RhoA/ROCK pathway and noncoding RNAs in ischemic stroke

Ischemic stroke is one of major causes of disability. In the pathological process of ischemic stroke, the up-regulation of Ras homolog gene family, member A (RhoA) and its downstream effector, Ras homolog gene family (Rho)-associated coiled coil-containing kinase (ROCK), contribute to the neuroinflammation, blood-brain barrier (BBB) dysfunction, neuronal apoptosis, axon growth inhibition and astrogliosis. Accumulating evidences have revealed that hydrogen sulphide (H₂S) could reduce brain injury in animal model of ischemic stroke via inhibiting the RhoA/ROCK pathway. Recently, noncoding RNAs (ncRNAs) such as circular RNAs (circRNAs), long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) have attracted much attention because of their essential role in adjusting gene expression both in physiological and pathological conditions. Numerous studies have uncovered the role of RhoA/ROCK pathway and ncRNAs in ischemic stroke. In this review, we focused on the role of H₂S, RhoA/ROCK pathway and ncRNAs in ischemic stroke and aimed to reveal new strategies for preventing and treating this devastating disease.

Neuroprotective effects of nobiletin on cerebral ischemia/reperfusion injury rats by inhibiting Rho/ROCK signaling pathway

Background

Nobiletin (NOB), an active natural flavonoid component of citrus, is used in Traditional Chinese Medicine for its anti-inflammatory activity, but its efficacy in cerebral ischemia/reperfusion (I/R) injury remains unclear.

Methods

In a middle cerebral artery occlusion (MCAO) rat model, MCAO rats were administered (Sham group and MCAO model group treated with an equal volume of solvent, NOB group treated with 10 or 20 mg/kg NOB) once a day for 7 days before cerebral ischemia and again after reperfusion, 2,3,5-triphenyltetrazolium chloride (TTC) staining was applied to assess the infarct area. Neurological function was evaluated by the modified neurological severity score and Morris water maze. The levels of inflammatory factors, interleukin 6 (IL-6), interleukin 1β (IL-1β) and tumor necrosis factor-α (TNF-α), were examined by enzyme-linked immunosorbent assay (ELISA). Histopathological staining evaluated neuron apoptosis in brain tissue. In an oxygen-glucose deprivation PC12 cell (OGD PC12) model, the proliferation, migration and apoptosis of OGD PC12 cells were detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and cell migration assays and flow cytometry. The gene and protein expression levels of Ras homolog gene family, member A (Rho A), ras-related C3 botulinum toxin substrate 1 (Rac 1), Rho-associated kinase 1 (ROCK 1), ROCK 2 in the Rho/ROCK pathway were measured by Real-time PCR (RT-PCR), immunohistochemistry and western blot.

Results

In rats with cerebral I/R injury, NOB significantly decreased the infarcted area, neuron apoptosis in brain tissue and expressions of IL-6, IL-1β, and TNF-α. It also improved neurological deficits in brain tissue and enhanced learning and memory ability. Further, NOB had a protective effect on OGD PC12 cells, increasing proliferation and migration and decreasing apoptosis. The expressions of Rho A, Rac 1, ROCK 1 and ROCK 2 were high in cerebral I/R injury rats, but were downregulated by NOB in I/R injury rats' brain tissue and OGD PC12 cells.

Conclusions

Nobiletin had a neuroprotective effect in rats with cerebral I/R injury, and its potential mechanism is decreasing neuron apoptosis by inhibiting the Rho/ROCK signaling pathway. These results suggest NOB is a promising neuroprotective agent for patients with cerebral ischemia.

Promising Advances in Pharmacotherapy for Patients with Spinal Cord Injury-A Review of Studies Performed In Vivo with Modern Drugs

Spinal cord injury (SCI) is a pathological neurological condition that leads to significant motor dysfunction. It is a condition that occurs as a result of tragic accidents, violent acts, or as a consequence of chronic diseases or degenerative changes. The current treatments for patients with SCI have moderate efficacy. They improve the quality of life of patients, but they are still doomed to long-term disability. In response to the modern directions of research on possible therapeutic methods that allow for the recovery of patients with SCI, a scientific review publication is needed to summarize the recent developments in this topic. The following review is focused on the available pharmacological treatments for SCIs and the problems that patients face depending on the location of the injury. In the following review, the research team describes problems related to spasticity and neuropathic pain; possible therapeutic pathways are also described for neuroprotection and the improvement of neurotransmission within the injured spinal cord, and the review focuses on issues related to oxidative stress.

Potential value of differentially expressed circular RNAs derived from circulating exosomes in the pathogenesis of rat spinal cord injury

Spinal cord injury (SCI) remains one kind of devastating neurological damage, and specific molecular mechanisms involved need to be understood deeply. Currently, circular RNAs (circRNAs), as a newly discovered type of non-coding RNAs (ncRNAs), have been under active investigation. Through functional interactions with disease-associated microRNAs (miRNAs), exosome-derived circRNAs have been extensively implicated in various organ pathogenesis. Nevertheless, the functional involvement of circulating circRNAs in SCI onset, progression as well as repair remains poorly explored until now. Of note, there still lacks clinical and experimental evidence in this regard. To obtain some relevant knowledge in this field, this study was originally designed to have a general overview of differentially expressed circRNAs derived from circulating exosomes in SCI rats in comparison with the control rats. It turned out that 709 types of downregulated circRNAs and 346 kinds of upregulated circRNAs were preliminarily screened out. Functional enrichment analyses including kyoto encyclopedia of genes and genomes (KEGG) pathway and gene ontology (GO) were performed to evaluate the possible biological functions of upregulated as well as downregulated circRNAs involved in SCI. Furthermore, five types of upregulated circulating circRNAs including chr4:208359914–208362182+, chr15:20088296–20092102+, chr1:175098934– 175134845–, chr1:175099657– 175128203–, and chr1:175104454– 175134845–, and plus five kinds of downregulated circulating circRNAs including chr11:74154652– 74159524–, chr12:45412398– 45412635–, chr7:137630261– 137648924–, chr6:6280974–6281188+, and chr4:225251864–225254087+, were verified through reverse transcription-polymerase chain reaction (RT-PCR). At last, taking these differentially expressed circRNAs in the center, the circRNA-miRNA-mRNA gene interaction network was constructed to predict the possible functionalities of circRNAs in SCI through anticipating specific interactive miRNAs, giving new insights into how circRNAs contribute to this pathological process. Taken together, these findings suggest the possible involvement and functional significance of circRNAs in SCI.

Lysophosphatidic Acid Induced Apoptosis, DNA Damage, and Oxidative Stress in Spinal Cord Neurons by Upregulating LPA4/LPA6 Receptors

Lysophosphatidic acid (LPA) has disruptive effects on lumbar spinal stenosis (LSS). Recently, LPA has been reported to be involved in spinal cord neuronal injury and toxicity, promoting the pathogenesis of LSS. However, the exact effects of LPA on spinal cord neurons remain unknown. The purpose of this study is to investigate the effects of LPA (18 : 1) on spinal cord neuronal cytotoxicity, apoptosis, DNA damage, and oxidative stress. After clinical detection of LPA secretion, spinal cord neurons were treated with LPA (18 : 1); cell viability was analyzed by MTT assay, and LDH leakage was detected by LDH kit; cell apoptosis was detected by flow cytometry; ROS production was measured by DCFDA staining and MitoSOX Red Staining; the activation of the Gα12/Gα13 signaling pathway was detected by serum response factor response element (SRF-RE) luciferase reporter gene; the relationship among LPA, LPA4/6, and ROCK was examined by western blotting. In spinal cord neurons treated with LPA (18 : 1), cellular activity decreased and LDH release increased. The Rho kinase inhibitor (Y-27632) can attenuate LPA-induced apoptosis, DNA damage, and oxidative stress in spinal cord neurons. Moreover mechanistic investigation indicated that LPA (18 : 1) activates Gα12/13–Rho–ROCK2-induced apoptosis, DNA damage, and oxidative stress in spinal cord neurons by upregulating LPA4/LPA6 receptors. Further, the Rho kinase inhibitor Y-27632 attenuates the effects of LPA by downregulating LPA4/LPA6 receptors. Taken together, the possible mechanism by which LPA secretion in LSS patients aggravates patient injury was further elucidated using an LPA-induced spinal cord neuronal injury cell model in vitro.

Rho Kinase Inhibitor Y27632 Improves Recovery After Spinal Cord Injury by Shifting Astrocyte Phenotype and Morphology via the ROCK/NF-κB/C3 Pathway

Spinal cord injury (SCI) usually results in loss or reduction in motor and sensory functions. Despite extensive research, no available therapy can restore the lost functions after SCI. Reactive astrocytes play a pivotal role in SCI. Rho kinase inhibitors have also been shown to promote functional recovery of SCI. However, the role of Rho kinase inhibitors in reactive astrocytic phenotype switch within SCI remains largely unexplored. In this study, astrocytes were treated with proinflammatory cytokines and/or the Rho kinase inhibitor Y27632. Concomitantly the phenotype and morphology of astrocytes were examined. Meanwhile, the SCI model of SD rats was established, and nerve functions were evaluated following treatment with Y27632. Subsequently, the number of A1 astrocytes in the injured area was observed and analyzed. Eventually, the expression levels of nuclear factor kappa B (NF-κB), C3, and S100A10 were measured. The present study showed that the Rho kinase inhibitor Y27632 improved functional recovery of SCI and elevated the proliferation and migration abilities of the astrocytes. In addition, Y27632 treatment initiated the switch of astrocytes morphology from a flattened shape to a process-bearing shape and transformed the reactive astrocytes A1 phenotype to an A2 phenotype. More importantly, further investigation suggested that Y27632 was actively involved in promoting the functional recovery of SCI in rats by inhabiting the ROCK/NF-κB/C3 signaling pathway. Together, Rho kinase inhibitor Y27632 effectively promotes the functional recovery of SCI by shifting astrocyte phenotype and morphology. Furthermore, the pro-regeneration event is strongly associated with the ROCK/NF-κB/C3 signal pathway.

Application of Small Molecules in the Central Nervous System Direct Neuronal Reprogramming

The lack of regenerative capacity of neurons leads to poor prognoses for some neurological disorders. The use of small molecules to directly reprogram somatic cells into neurons provides a new therapeutic strategy for neurological diseases. In this review, the mechanisms of action of different small molecules, the approaches to screening small molecule cocktails, and the methods employed to detect their reprogramming efficiency are discussed, and the studies, focusing on neuronal reprogramming using small molecules in neurological disease models, are collected. Future research efforts are needed to investigate the in vivo mechanisms of small molecule-mediated neuronal reprogramming under pathophysiological states, optimize screening cocktails and dosing regimens, and identify safe and effective delivery routes to promote neural regeneration in different neurological diseases.

Adaptive Swarm Fuzzy Logic Controller of Multi-Joint Lower Limb Assistive Robot

The idea of developing a multi-joint rehabilitation robot is to satisfy the demands for recovery of lower limb functionality in hemiplegic impairments and assist the physiotherapists with their therapy plans. This work aims at to implement the Lyapunov Adaptive and Swarm-Fuzzy Logic Control (LASFC) strategy of 4-degree of freedom (4-DoF) Lower Limb Assistive Robot (LLAR) application, in which the control law is an integration of swarm-fuzzy logic control (SFLC) and Lyapunov adaptive control (LAC) with particle swarm optimization (PSO). The controller is established based on the sliding filtered steady-state error for SFLC. Its parameters are tuned by using PSO for the mathematical model of LLAR. The fuzzy defuzzification membership is set based on the tuned parameters for the real-time control system. LAC strategy is determined using stability analysis of the system to choose the controller’s parameters by observation of the system’s output and reference. The control law implemented in LLAR is the integration of SFLC and LAC to adjust the input voltage of joints. The parameters tuned by PSO are compared with the genetic algorithm (GA) statistically. In addition, the real-time trajectory tracking of the proposed controller for each joint is compared with LAC and SFLC separately. The experiment revealed that the LASFC has superior performance to the other two methods in trajectory tracking. For example, the average error for left hip by LASFC is 53.57% and 68% lower than SFLC and LAC, respectively. By the statistical analysis, it can be ascertained that the LASFC strategy performed efficiently for real-time control of the joint trajectory tracking.

Association of MicroRNAs With Risk of Stroke: A Meta-Analysis

Objectives

Altered expression of microRNAs (miRNAs) may contribute to disease vulnerability. Studies have reported the involvement of miRNA in the pathophysiology of ischemic stroke.

Methods

We performed a meta-analysis of data from 6 studies that used a panel of miRNAs with altered expressions to diagnose ischemic stroke with the Bayesian framework. The I² test and Cochran's Q-statistic were used to assess heterogeneity. Funnel plots were generated and publication bias was assessed using Begg and Egger tests.

Results

On summary receiver operating characteristics (SROC) curve analysis, the pooled sensitivity and specificity of altered miRNA expressions for diagnosis of ischemic stroke was 0.92 (95% confidence interval [CI] 0.80–0.97) and 0.83 (95% CI 0.71–0.90), respectively; the diagnostic odds ratio was 54.35 (95% CI 20.39–144.92), and the area under the SROC curve was 0.93 (95% CI 0.90–0.95).

Conclusions

Our results showed a link between dysregulation of miRNAs and the occurrence of ischemic stroke. Abnormal miRNA expression may be a potential biomarker for ischemic stroke.

RhoA Signaling in Neurodegenerative Diseases

Ras homolog gene family member A (RhoA) is a small GTPase of the Rho family involved in regulating multiple signal transduction pathways that influence a diverse range of cellular functions. RhoA and many of its downstream effector proteins are highly expressed in the nervous system, implying an important role for RhoA signaling in neurons and glial cells. Indeed, emerging evidence points toward a role of aberrant RhoA signaling in neurodegenerative diseases such as Parkinson’s disease, Alzheimer’s disease, Huntington’s disease, and amyotrophic lateral sclerosis. In this review, we summarize the current knowledge of RhoA regulation and downstream cellular functions with an emphasis on the role of RhoA signaling in neurodegenerative diseases and the therapeutic potential of RhoA inhibition in neurodegeneration.