ROCK as a therapeutic target for ischemic stroke

The novel ROCK2 selective inhibitor NRL-1049 preserves the blood-brain barrier after acute injury

Endothelial blood-brain barrier (BBB) dysfunction is critical in the pathophysiology of brain injury. Rho-associated protein kinase (ROCK) activation disrupts BBB integrity in the injured brain. We aimed to test the efficacy of a novel ROCK2 inhibitor in preserving the BBB after acute brain injury. We characterized the molecular structure and pharmacodynamic and pharmacokinetic properties of a novel selective ROCK2 inhibitor, NRL-1049, and its first metabolite, 1-hydroxy-NRL-1049 (referred to as NRL-2017 hereon) and tested the efficacy of NRL-1049 on the BBB integrity in rodent models of acute brain injury. Our data show that NRL-1049 and NRL-2017 both inhibit ROCK activity and are 44-fold and 17-fold more selective towards ROCK2 than ROCK1, respectively. When tested in a mouse model of cortical cryoinjury, NRL-1049 significantly attenuated the increase in water content. Interestingly, 60% of the mice in the vehicle arm developed seizures within 2 hours after cryoinjury versus none in the NRL-1049 arm. In spontaneously hypertensive rats, NRL-1049 attenuated the dramatic surge in Evans Blue extravasation compared with the vehicle arm after transient middle cerebral artery occlusion. Hemorrhagic transformation was also reduced. We show that NRL-1049, a selective ROCK2 inhibitor, is a promising drug candidate to preserve the BBB after brain injury.

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.

H2S-RhoA/ROCK Pathway and Glial Cells in Axonal Remyelination After Ischemic Stroke

Ischemic stroke is one of the main reasons of disability and death. Stroke-induced functional deficits are mainly due to the secondary degeneration of the white matter characterized by axonal demyelination and injury of axon-glial integrity. Enhancement of the axonal regeneration and remyelination could promote the neural functional recovery. However, cerebral ischemia-induced activation of RhoA/Rho kinase (ROCK) pathway plays a crucial and harmful role in the process of axonal recovery and regeneration. Inhibition of this pathway could promote the axonal regeneration and remyelination. In addition, hydrogen sulfide (H2S) has the significant neuroprotective role during the recovery of ischemic stroke via inhibiting the inflammatory response and oxidative stress, regulating astrocyte function, promoting the differentiation of endogenous oligodendrocyte precursor cells (OPCs) to mature oligodendrocyte. Among all of these effects, promoting the formation of mature oligodendrocyte is a crucial part of axonal regeneration and remyelination. Furthermore, numerous studies have uncovered the crosstalk between astrocytes and oligodendrocyte, microglial cells and oligodendrocyte in the axonal remyelination following ischemic stroke. The purpose of this review was to discuss the relationship among H2S, RhoA/ROCK pathway, astrocytes, and microglial cells in the axonal remyelination following ischemic stroke to reveal new strategies for preventing and treating this devastating disease.

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.

Chromatin accessibility dynamics of neurogenic niche cells reveal defects in neural stem cell adhesion and migration during aging

The regenerative potential of brain stem cell niches deteriorates during aging. Yet the mechanisms underlying this decline are largely unknown. Here we characterize genome-wide chromatin accessibility of neurogenic niche cells in vivo during aging. Interestingly, chromatin accessibility at adhesion and migration genes decreases with age in quiescent neural stem cells (NSCs) but increases with age in activated (proliferative) NSCs. Quiescent and activated NSCs exhibit opposing adhesion behaviors during aging: quiescent NSCs become less adhesive, whereas activated NSCs become more adhesive. Old activated NSCs also show decreased migration in vitro and diminished mobilization out of the niche for neurogenesis in vivo. Using tension sensors, we find that aging increases force-producing adhesions in activated NSCs. Inhibiting the cytoskeletal-regulating kinase ROCK reduces these adhesions, restores migration in old activated NSCs in vitro, and boosts neurogenesis in vivo. These results have implications for restoring the migratory potential of NSCs and for improving neurogenesis in the aged brain.

Emerging Targets for Modulation of Immune Response and Inflammation in Stroke

The inflammatory and immunological responses play a significant role after stroke. The innate immune activation stimulated by microglia during stroke results in the migration of macrophages and lymphocytes into the brain and are responsible for tissue damage. The immune response and inflammation following stroke have no defined targets, and the intricacies of the immunological and inflammatory processes are only partially understood. Innate immune cells enter the brain and meninges during the acute phase, which can cause ischemia damage. Activation of systemic immunity is caused by danger signals sent into the bloodstream by injured brain cells, which is followed by a significant immunodepression that encourages life-threatening infections. Neuropsychiatric sequelae, a major source of post-stroke morbidity, may be induced by an adaptive immune response that is initiated by antigen presentation during the chronic period and is directed against the brain. Thus, the current review discusses the role of immune response and inflammation in stroke pathogenesis, their role in the progression of injury during the stroke, and the emerging targets for the modulation of the mechanism of immune response and inflammation that may have possible therapeutic benefits against stroke.

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.

Involvement of Rho-Associated Coiled-Coil Containing Kinase (ROCK) in BCR-ABL1 Tyrosine Kinase Inhibitor Cardiovascular Toxicity

Background

Second- and third-generation BCR-ABL1 tyrosine kinase inhibitors (TKIs) are associated with cardiovascular adverse events (CVAEs) in patients with Philadelphia chromosome-positive (Ph+) leukemia.

Objectives

We hypothesized that second- and third-generation BCR-ABL1 TKIs may cause CVAEs through the activation of Rho-associated coiled-coil containing kinase (ROCK).

Methods

Peripheral blood mononuclear cells from 53 Ph+ patients on TKIs and 15 control patients without Ph+ leukemia were assessed for ROCK activity through capillary electrophoresis (median follow-up = 26 months [Q1-Q3: 5-37 months]). We also investigated the effects of TKIs and ROCK on endothelial dysfunction in vitro, which could contribute to CVAEs.

Results

Patients receiving second- and third-generation TKIs had 1.6-fold greater ROCK activity compared with patients receiving imatinib and control patients. Elevated ROCK activity was associated with an increased incidence of CVAEs in Ph+ leukemia patients. In endothelial cells in vitro, we found that dasatinib and ponatinib treatment led to changes in actin intensity and endothelial permeability, which can be reversed by pharmacologic inhibition of ROCK. Ponatinib led to decreased cell proliferation, but this was not accompanied by senescence. Dasatinib and ponatinib treatment led to phosphor-inhibition of endothelial nitric oxide synthase and decreased nitric oxide production. ROCK inhibition reversed endothelial permeability and endothelial nitric oxide synthase-related endothelial dysfunction. Imatinib and nilotinib induce phosphorylation of p190RhoGAP.

Conclusions

Our findings suggest ROCK activity may be a prognostic indicator of CVAEs in patients receiving BCR-ABL1 TKIs. With further study, ROCK inhibition may be a promising approach to reduce the incidence of CVAEs associated with second- and third-generation BCR-ABL1 TKIs.

Protection against Hypoxia-Reoxygenation Injury of Hippocampal Neurons by H2S via Promoting Phosphorylation of ROCK2 at Tyr722 in Rat Model

The RhoA-ROCK signaling pathway is associated with the protective effects of hydrogen sulfide (H₂S) against cerebral ischemia. H₂S protects rat hippocampal neurons (RHNs) against hypoxia-reoxygenation (H/R) injury by promoting phosphorylation of RhoA at Ser188. However, effect of H₂S on the phosphorylation of ROCK₂-related sites is unclear. The present study was designed to investigate whether H₂S can play a role in the phosphorylation of ROCK₂ at Tyr722, and explore whether this role mediates the protective effect of H/R injury in RHNs. Prokaryotic recombinant plasmids ROCK₂^wild-pGEX-6P-1 and ROCK₂^Y722F-pGEX-6P-1 were constructed and transfected into E. coli in vitro, and the expressed protein, GST-ROCK₂^wild and GST-ROCK₂^Y722F were used for phosphorylation assay in vitro. Eukaryotic recombinant plasmids ROCK₂^Y722-pEGFP-N1 and ROCK₂^Y722F-pEGFP-N1 as well as empty plasmid were transfected into the RHNs. Western blot assay and whole-cell patch-clamp technique were used to detect phosphorylation of ROCK₂ at Tyr722 and BK_Ca channel current in the RHNs, respectively. Cell viability, leakages of intracellular enzymes lactate dehydrogenase (LDH), and nerve-specific enolase (NSE) were measured. The H/R injury was indicated by decrease of cell viability and leakages of intracellular LDH and NSE. The results of Western blot have shown that NaHS, a H₂S donor, significantly promoted phosphorylation of GST-ROCK₂^wild at Tyr722, while no phosphorylation of GST-ROCK₂^Y722F was detected. The phosphorylation of ROCK₂^wild promoted by NaHS was also observed in RHNs. NaHS induced more potent effects on protection against H/R injury, phosphorylation of ROCK₂ at Tyr722, inhibition of ROCK₂ activity, as well as increase of the BK_Ca current in the ROCK₂^Y722-pEGFP-N1-transfected RHNs. Our results revealed that H₂S protects the RHNs from H/R injury through promoting phosphorylation of ROCK₂ at Tyr722 to inhibit ROCK₂ activity and potentially by opening channel currents.

Enhancement of Phosphorylation and Transport Activity of the Neuronal Glutamate Transporter Excitatory Amino Acid Transporter 3 by C3bot and a 26mer C3bot Peptide

In primary murine hippocampal neurons we investigated the regulation of EAAT3-mediated glutamate transport by the Clostridium botulinum C3 transferase C3bot and a 26mer peptide derived from full length protein. Incubation with either enzyme-competent C3bot or enzyme-deficient C3bot156–181 peptide resulted in the upregulation of glutamate uptake by up to 22% compared to untreated cells. A similar enhancement of glutamate transport was also achieved by the classical phorbol-ester-mediated activation of protein kinase C subtypes. Yet comparable, effects elicited by C3 preparations seemed not to rely on PKCα, γ, ε, or ζ activation. Blocking of tyrosine phosphorylation by tyrosine kinase inhibitors prevented the observed effect mediated by C3bot and C3bot 26mer. By using biochemical and molecular biological assays we could rule out that the observed C3bot and C3bot 26mer-mediated effects solely resulted from enhanced transporter expression or translocation to the neuronal surface but was rather mediated by transporter phosphorylation at tyrosine residues that was found to be significantly enhanced following incubation with either full length protein or the 26mer C3 peptide.

CD44 mediates shear stress mechanotransduction in an in vitro blood-brain barrier model through small GTPases RhoA and Rac1

Fluid shear stress is an important mediator of vascular permeability, yet the molecular mechanisms underlying the effect of shear on the blood-brain barrier (BBB) have yet to be clarified in cerebral vasculature despite its importance for brain homeostasis. The goal of this study is to probe components of shear mechanotransduction within the BBB to gain a better understanding of pathologies associated with changes in cerebral perfusion including ischemic stroke. Interrogating the effects of shear stress in vivo is complicated by the complexity of factors in the brain parenchyma and the difficulty associated with modulating blood flow regimes. The in vitro model used in this study is compatible with real-time measurement of barrier function using a transendothelial electrical resistance as well as immunocytochemistry and dextran permeability assays. These experiments reveal that there is a threshold level of shear stress required for barrier formation and that the composition of the extracellular matrix, specifically the presence of high molecular weight hyaluronan, dictates the flow response. Gene editing to modulate the expression of CD44, a mechanosensitive receptor for hyaluronan, demonstrates that the receptor is required for the endothelial response to shear stress. Manipulation of small GTPase activity reveals CD44 activates Rac1 while inhibiting RhoA activation. Additionally, adducin-γ localizes to tight junctions in response to shear stress and RhoA inhibition and is required to maintain the barrier. This study identifies specific components of the mechanosensing complex associated with the BBB response to fluid shear stress and, therefore, illuminates potential targets for barrier manipulation in vivo.

Circ_HECTD1 regulates cerebral ischemia injury via mechanisms involving the regulation of let-7c-5p/ROCK1 axis

BACKGROUND

Ischemia is the main cause of cerebral ischemic stroke with a high mortality rate, and it is affected by the dysfunction of circular RNAs. The underlying molecular mechanisms of circ_HECTD1 were explored in cerebral ischemia stroke.

METHODS

PC-12 cells were treated with oxygen-glucose deprivation/reoxygenation (OGD/R) as the cell model of cerebral ischemia model. The expression levels of circ_HECTD1, let-7c-5p, and Rho-associated coiled-coil-containing protein kinase 1 (ROCK1) were determined by quantitative real-time PCR in PC-12 cells. The proliferation ability of PC-12 cells was assessed by 5-ethynyl-2'-deoxyuridine and 3-(4,5-dimethylthizol-2-yl)-2,5-diphenyltetrazolium bromide assays. The protein expression levels were quantified by western blot analysis. Flow cytometry was performed to analyze cell apoptosis. Lactate dehydrogenase concentration was assessed by a commercialized kit. Dual-luciferase reporter assay was used to confirm the interaction relationships among circ_HECTD1, let-7c-5p and ROCK1.

RESULTS

Circ_HECTD1 was upregulated in OGD/R-treated PC-12 cells. The results also showed that cell proliferation was decreased and apoptosis was increased in OGD/R-treated PC-12 cells, which was overturned by the inhibition of circ_HECTD1. Let-7c-5p was a target of circ_HECTD1, and the protective effects of circ_HECTD1 knockdown on OGD/R-treated PC-12 cells were canceled after co-transfection with let-7c-5p inhibitor. We found that ROCK1 was a potential target of let-7c-5p. Let-7c-5p -mediated the effects on the proliferation and apoptosis of OGD/R-treated PC-12 cells by targeting ROCK1.

CONCLUSION

Circ_HECTD1 was implicated in the development of cerebral ischemia stroke. Knockdown of circ_HECTD1 protected against cerebral ischemia injury in OGD/R-treated PC-12 cells depending on the regulation of let-7c-5p/ROCK1 axis.

Rho GTPases in kidney physiology and diseases

Rho family GTPases are molecular switches best known for their pivotal role in dynamic regulation of the actin cytoskeleton, but also of cellular morphology, motility, adhesion and proliferation. The prototypic members of this family (RhoA, Rac1 and Cdc42) also contribute to the normal kidney function and play important roles in the structure and function of various kidney cells including tubular epithelial cells, mesangial cells and podocytes. The kidney's vital filtration function depends on the structural integrity of the glomerulus, the proximal portion of the nephron. Within the glomerulus, the architecturally actin-based cytoskeleton podocyte forms the final cellular barrier to filtration. The glomerulus appears as a highly dynamic signalling hub that is capable of integrating intracellular cues from its individual structural components. Dynamic regulation of the podocyte cytoskeleton is required for efficient barrier function of the kidney. As master regulators of actin cytoskeletal dynamics, Rho GTPases are therefore of critical importance for sustained kidney barrier function. Dysregulated activities of the Rho GTPases and of their effectors are implicated in the pathogenesis of both hereditary and idiopathic forms of kidney diseases. Diabetic nephropathy is a progressive kidney disease that is caused by injury to kidney glomeruli. High glucose activates RhoA/Rho-kinase in mesangial cells, leading to excessive extracellular matrix production (glomerulosclerosis). This RhoA/Rho-kinase pathway also seems involved in the post-transplant hypertension frequently observed during treatment with calcineurin inhibitors, whereas Rac1 activation was observed in post-transplant ischaemic acute kidney injury.

Effect of Naoluoxintong on the NogoA/RhoA/ROCK pathway by down-regulating DNA methylation in MCAO rats

ETHNOPHARMACOLOGICAL RELEVANCE

Naoluoxintong (NLXT) is a traditional Chinese Medicine (TCM) prescription that is clinically used in the treatment of ischemic stroke (IS). However, its therapeutic mechanism remains unclear.

AIM OF THE STUDY

To obtain the mechanism of NLXT by observing the protective effects of NLXT on the NogoA/RhoA/Rock pathway in a rat model of IS by regulating DNA methylation.

MATERIALS AND METHODS

Rats were divided into five groups using a random number table: normal group, model group, NLXT group, blocker group I (NLXT + SGI-1027) and blocker group II (NLXT + Y27632). The right middle cerebral artery occlusion-reperfusion (MCAO/R) rat model was made, and the regional cerebral blood flow (rCBF) of each group was detected using laser Doppler. The methylation levels of CpG sites of neurite outgrowth inhibitor protein-A (Nogo-A), Nogo receptor (NgR), ras homolog gene family member A (RhoA) and rho-associated coiled-coil protein kinase 2 (ROCK2) genes in rat brain tissue were detected using the bisulfite method. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect NogoA, RhoA, NgR1, NgR2 and ROCK2 mRNA expression in rat brain tissue. NogoA, RhoA, NgR1, NgR2 and ROCK2 proteins were detected using immunoblotting in rat brain tissue.

RESULTS

After the modeling of middle cerebral artery occlusion (MCAO), neurological deficit test was made to ensure the success of the modeling. At each time point after surgery, the rCBF of the other groups decreased compared with the normal group (P < 0.01 or P < 0.05). Meanwhile, the rCBF increased in blocker group I as well as blocker group II after 3 days (P < 0.05). There were differences in the DNA methylation sites of NogoA, RhoA, NgR and ROCK2 genes between the model group and the NLXT group (P < 0.05). Compared with the normal group, NogoA, NgR1, NgR2, RhoA and ROCK2 gene expression in the model group increased observably (P < 0.01). In comparison with the model group, NogoA and NgR1 gene expression in the blocker group II was prominently observed on the 1st day. NogoA, NgR1, NgR2, RhoA and ROCK2 gene expression remarkably reduced (P < 0.01) on the 3rd and 7th days. Compared with the normal group, NogoA, RhoA, NgR1, NgR2 and ROCK2 protein expression in the model group increased observably (P < 0.01). In comparison with the model group, NogoA, RhoA, NgR1, NgR2 and ROCK2 protein expression in the other groups declined prominently (P < 0.01).

CONCLUSION

NLXT can reduce the DNA methylation level of NogoA pathway after IS, thus inhibit the expression of NogoA/RhoA/ROCK pathway from producing anti-cerebral ischemia pharmacological effect.

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

Ischemic strokes (IS) and spinal cord injuries (SCI) are major causes of disability. RhoA is a small GTPase protein that activates a downstream effector, ROCK. The up-regulation of the RhoA/ROCK pathway contributes to neuronal apoptosis, neuroinflammation, blood-brain barrier dysfunction, astrogliosis, and axon growth inhibition in IS and SCI. Noncoding RNAs (ncRNAs), such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), were previously considered to be non-functional. However, they have attracted much attention because they play an essential role in regulating gene expression in physiological and pathological conditions. There is growing evidence that ROCK inhibitors, such as fasudil and VX-210, can reduce injury in IS and SCI in animal models and clinical trials. Recently, it has been reported that miRNAs are decreased in IS and SCI, while lncRNAs are increased. Inhibiting the Rho/ROCK pathway with miRNAs alleviates apoptosis, neuroinflammation, oxidative stress, and axon growth inhibition in IS and SCI. Further studies are required to explore the significance of ncRNAs in IS and SCI and to establish new strategies for preventing and treating these devastating diseases.

Deregulated Protein Kinases: Friend and Foe in Ischemic Stroke

Ischemic stroke is the third leading cause of mortality worldwide, but its medical management is still limited to the use of thrombolytics as a lifesaving option. Multiple molecular deregulations of the protein kinase family occur during the period of ischemia/reperfusion. However, experimental studies have shown that alterations in the expression of essential protein kinases and their pharmacological modulation can modify the neuropathological milieu and hasten neurophysiological recovery. This review highlights the role of key protein kinase members and their implications in the evolution of stroke pathophysiology. Activation of ROCK-, MAPK-, and GSK-3β-mediated pathways following neuronal ischemia/reperfusion injury in experimental conditions aggravate the neuropathology and delays recovery. Targeting ROCK, MAPK, and GSK-3β will potentially enhance myelin regeneration, improve blood-brain barrier (BBB) function, and suppress inflammation, which ameliorates neuronal survival. Conversely, protein kinases such as PKA, Akt, PKCα, PKCε, Trk, and PERK salvage neurons post-ischemia by mechanisms including enhanced toxin metabolism, restoring BBB integrity, neurotrophic effects, and apoptosis suppression. Certain protein kinases such as ERK1/2, JNK, and AMPK have favourable and unfavourable effects in salvaging ischemia-injured neurons. Targeting multiple protein kinase-mediated pathways simultaneously may improve neuronal recovery post-ischemia.

Combined Treatment of Bone Marrow Mesenchymal Stem Cells and Fasudil Promotes Neurovascular Remodeling and Neurological Function Recovery in Ischemic Stroke

Stroke remains a highly deadly and disabling disease with limited treatment tragedies due to the limitations of available treatments; novel therapies for stroke are needed. In this article, the synergistic results of dual bone marrow mesenchymal stem cells (BMSC) and fasudil treatment in rat models of ischemic stroke still require further identification. Sprague-Dawley rats were used to construct the middle cerebral artery, occlusion models. BMSCs were incubated with fasudil, and MTT was performed to evaluate cell proliferation. The rats were treated with fasudil + BMSC, BMSC, fasudil, and saline. Blood samples were collected for complete blood count analysis and measurement of serum TNF-α levels. The neurological functions were evaluated. After the rats were sacrificed, immunohistochemical staining and TTC staining was performed. Fasudil promoted the proliferation of BMSCs and induced their differentiation into neuron-like cells. BMSCs increased the proportion of neutrophils; nevertheless, fasudil counteracted the neutrophil increase. The TUJ-1/MAP2/VIII factor expression in the fasudil + BMSC group was significantly higher than that in the other groups. The number of GFAP-positive cells decreased in the fasudil + BMSC and BMSC alone groups. The infarct volume in the fasudil + BMSC and BMSC alone groups was significantly lower than in the fasudil alone and control groups. Both BMSCs and fasudil exert neurorestorative effects in rat models of cerebral ischemia. Fasudil neutralizes the pro-inflammatory effects of BMSCs, while BMSCs and fasudil together had synergistic effects promoting neurovascular remodeling and neurological function recovery in stroke. A combination of BMSCs and fasudil provides a promising method for the treatment of ischemic stroke.

Effect of RGD functionalization and stiffness of gellan gum hydrogels on macrophage polarization and function

Macrophages, the primary effector cells in the immune response, respond rapidly to the physical or chemical properties of biomaterial implants. Balanced macrophage polarization, phagocytosis, and migration would be beneficial for implant success and tissue regeneration. Here, we investigated macrophage phenotypic changes, phagocytosis, and migration in response to RGD functionalized surfaces and changes in stiffness of gellan gum hydrogels. We also inhibited the RhoA pathway. The compressive moduli ranged from ~5 to 30 kPa. Cell population and cell spreading area of classically activated macrophages (M(LPS)) and alternatively activated macrophages (M(IL-4)) are promoted on RGD modified hydrogel. ROCK inhibitor induced the opposite effect on the cell spreading of both M(LPS) and M(IL-4) macrophages on RGD modified hydrogels. Macrophage polarization was found to be stiffness-driven and regulated by the RGD motif and blocked by the RhoA pathway. RGD functionalized hydrogel shifted M(IL-4) cells toward a more pro-inflammatory phenotype, while ROCK inhibition shifted M(LPS) cells to a more anti-inflammatory phenotype. Both M(LPS) and M(IL-4) cells on untreated hydrogels shifted to a more pro-inflammatory phenotype in the presence of aminated-PS particles. The RGD motif had a significant impact on cellular uptake, whereas cellular uptake was stiffness driven on untreated hydrogels. Cell migration of M(LPS) and M(IL-4) cells had ROCK-dependent migration. The stiffness of gellan gum hydrogels had no influence on macrophage migration rate. Collectively, our results showed that gellan gum hydrogels can be used to direct immune response, macrophage infiltration, and phagocytosis.

ROCK Inhibition as Potential Target for Treatment of Pulmonary Hypertension

Pulmonary hypertension (PH) is a cardiovascular disease caused by extensive vascular remodeling in the lungs, which ultimately leads to death in consequence of right ventricle (RV) failure. While current drugs for PH therapy address the sustained vasoconstriction, no agent effectively targets vascular cell proliferation and tissue inflammation. Rho-associated protein kinases (ROCKs) emerged in the last few decades as promising targets for PH therapy, since ROCK inhibitors demonstrated significant anti-remodeling and anti-inflammatory effects. In this review, current aspects of ROCK inhibition therapy are discussed in relation to the treatment of PH and RV dysfunction, from cell biology to preclinical and clinical studies.

PEA prevented early BBB disruption after cerebral ischaemic/reperfusion (I/R) injury through regulation of ROCK/MLC signaling

Palmitoylethanolamide (PEA) offers a strong protection against BBB disruption and neurological deficits after cerebral ischaemic/reperfusion (I/R) injury. To date, these BBB protective effects of PEA are mainly attributed to PPARα-mediated actions. However, whether PEA protects against BBB disruption through direct regulation of cytoskeletal microfilaments remains unknown. Here, we identified PEA as a Rho-associated protein kinase (ROCK2) inhibitor (IC₅₀ = 38.4 ± 4.8 μM). In vitro data suggested that PEA reduced the activation of ROCK/MLC signaling and stress fiber formation within microvascular endothelial cells (ECs) after oxygen-glucose deprivation (OGD), and consequently attenuated early (0-4 h) EC barrier disruption. These actions of PEA could not be blocked by the PPARα antagonist GW6471. In summary, the present study described a previously unexplored role of PEA as a ROCK2 inhibitor, and propose a PPARα-independent mechanism for pharmacological effects of PEA.

Motor tract reorganization after acute central nervous system injury: a translational perspective

Acute central nervous system injuries are among the most common causes of disability worldwide, with widespread social and economic implications. Motor tract injury accounts for the majority of this disability; therefore, there is impetus to understand mechanisms underlying the pathophysiology of injury and subsequent reorganization of the motor tract that may lead to recovery. After acute central nervous system injury, there are changes in the microenvironment and structure of the motor tract. For example, ischemic stroke involves decreased local blood flow and tissue death from lack of oxygen and nutrients. Traumatic injury, in contrast, causes stretching and shearing injury to microstructures, including myelinated axons and their surrounding vessels. Both involve blood-brain barrier dysfunction, which is an important initial event. After acute central nervous system injury, motor tract reorganization occurs in the form of cortical remapping in the gray matter and axonal regeneration and rewiring in the white matter. Cortical remapping involves one cortical region taking on the role of another. cAMP-response-element binding protein is a key transcription factor that can enhance plasticity in the peri-infarct cortex. Axonal regeneration and rewiring depend on complex cell-cell interactions between axons, oligodendrocytes, and other cells. The RhoA/Rho-associated coiled-coil containing kinase signaling pathway plays a central role in axon growth/regeneration through interactions with myelin-derived axonal growth inhibitors and regulation of actin cytoskeletal dynamics. Oligodendrocytes and their precursors play a role in myelination, and neurons are involved through their voltage-gated calcium channels. Understanding the pathophysiology of injury and the biology of motor tract reorganization may allow the development of therapies to enhance recovery after acute central nervous system injury. These include targeted rehabilitation, novel pharmacotherapies, such as growth factors and axonal growth inhibitor blockade, and the implementation of neurotechnologies, such as central nervous system stimulators and robotics. The translation of these advances depends on careful alignment of preclinical studies and human clinical trials. As experimental data mount, the future is one of optimism.

CD151 Alleviates Early Blood-Brain Barrier Dysfunction After Experimental Focal Brain Ischemia in Rats

Preservation of the blood-brain barrier (BBB) function is a potential protective strategy against cerebral ischemic injuries. CD151 has a beneficial effect in maintaining vascular stability and plays a role in pro-angiogenesis. Both vascular stability and angiogenesis can affect BBB function. Therefore, we aimed to examine the action of CD151 in regulating BBB permeability after cerebral ischemic injury in the present study. Using a transient focal cerebral ischemia (tFCI) rat model, we established that CD151 overexpression in the brain mitigated the leakage of endogenous IgG at 6-24 h after tFCI in vivo. Moreover, we found that CD151 can decrease the diffusion of macromolecules through monolayer brain microvessel endothelial cells (BMVECs) after glucose and oxygen deprivation (OGD)-reoxygenation in vitro. Furthermore, overexpression of CD151 in BMVECs suppressed OGD-reoxygenation-induced F-actin formation and RhoA activity. However, while preserving BBB integrity after tFCI, CD151 overexpression did not affect the post-stroke outcomes. Taken together, the present study demonstrated that CD151 overexpression in the brain protects BBB permeability at early phase after tFCI. CD151 may be a potential target for early BBB protection in ischemic stroke.

N-Methyl-D-Aspartate Receptor Signaling-Protein Kinases Crosstalk in Cerebral Ischemia

Although stroke is very often the cause of death worldwide, the burden of ischemic and hemorrhagic stroke varies between regions and over time regarding differences in prognosis, prevalence of risk factors, and treatment strategies. Excitotoxicity, oxidative stress, dysfunction of the blood-brain barrier, neuroinflammation, and lysosomal membrane permeabilization, sequentially lead to the progressive death of neurons. In this process, protein kinases-related checkpoints tightly regulate N-methyl-D-aspartate (NMDA) receptor signaling pathways. One of the major hallmarks of cerebral ischemia is excitotoxicity, characterized by overactivation of glutamate receptors leading to intracellular Ca²⁺ overload and ultimately neuronal death. Thus, reduced expression of postsynaptic density-95 protein and increased protein S-nitrosylation in neurons is responsible for neuronal vulnerability in cerebral ischemia. In this chapter death-associated protein kinases, cyclin-dependent kinase 5, endoplasmic reticulum stress-induced protein kinases, hyperhomocysteinemia-related NMDA receptor overactivation, ephrin-B-dependent amplification of NMDA-evoked neuronal excitotoxicity and lysosomocentric hypothesis have been discussed.Consequently, ample evidences have demonstrated that enhancing extrasynaptic NMDA receptor activity triggers cell death after stroke. In this context, considering the dual roles of NMDA receptors in both promoting neuronal survival and mediating neuronal damage, selective augmentation of NR2A-containing NMDA receptor activation in the presence of NR2B antagonist may constitute a promising therapy for stroke.

YiQiFuMai Lyophilized Injection ameliorates tPA-induced hemorrhagic transformation by inhibiting cytoskeletal rearrangement associated with ROCK1 and NF-κB signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Thrombolytic therapy with tissue plasminogen activator (tPA) after ischemic stroke exacerbates blood-brain barrier (BBB) breakdown and leads to hemorrhagic transformation (HT). YiQiFuMai Lyophilized Injection (YQFM) is a modern preparation derived from Sheng-mai San (a traditional Chinese medicine). YQFM attenuates the BBB dysfunction induced by cerebral ischemia-reperfusion injury. However, whether YQFM can suppress tPA-induced HT remains unknown.

AIM OF THE STUDY

We investigated the therapeutic effect of YQFM on tPA-induced HT and explored the underlying mechanisms in vivo and in vitro to improve the safety of tPA use against stroke.

METHODS

Male C57BL/6J mice were subjected to 45 min of ischemia and 24 h of reperfusion. tPA (10 mg/kg) were infused 2 h after occlusion and YQFM (0.671 g/kg) was injected 2.5 h after occlusion. The in vitro effect of YQFM (100, 200, 400 μg/mL) on tPA (60 μg/mL)-induced dysfunction of the microvascular endothelial barrier in the brain following oxygen-glucose deprivation/reoxygenation (OGD/R) was observed in bEnd.3 cells.

RESULTS

YQFM suppressed tPA-induced high hemoglobin level in the brain, mortality, neurologic severity score, BBB permeability, expression and activation of matrix metalloproteinase (MMP)-9 and MMP-2, and degradation of tight-junction proteins. Furthermore, YQFM significantly blocked tPA-induced brain microvascular endothelial permeability and phosphorylation of Rho-associated kinase (ROCK)1, myosin light chain (MLC), cofilin and p65 in vivo and in vitro.

CONCLUSION

YQFM suppressed tPA-induced HT by inhibiting cytoskeletal rearrangement linked with ROCK-cofilin/MLC pathways and inhibiting the nuclear factor-kappa B pathway to ameliorate BBB damage caused by tPA.

Wnt Pathway: An Emerging Player in Vascular and Traumatic Mediated Brain Injuries

The Wnt pathway, which comprises the canonical and non-canonical pathways, is an evolutionarily conserved mechanism that regulates crucial biological aspects throughout the development and adulthood. Emergence and patterning of the nervous and vascular systems are intimately coordinated, a process in which Wnt pathway plays particularly important roles. In the brain, Wnt ligands activate a cell-specific surface receptor complex to induce intracellular signaling cascades regulating neurogenesis, synaptogenesis, neuronal plasticity, synaptic plasticity, angiogenesis, vascular stabilization, and inflammation. The Wnt pathway is tightly regulated in the adult brain to maintain neurovascular functions. Historically, research in neuroscience has emphasized essentially on investigating the pathway in neurodegenerative disorders. Nonetheless, emerging findings have demonstrated that the pathway is deregulated in vascular- and traumatic-mediated brain injuries. These findings are suggesting that the pathway constitutes a promising target for the development of novel therapeutic protective and restorative interventions. Yet, targeting a complex multifunctional signal transduction pathway remains a major challenge. The review aims to summarize the current knowledge regarding the implication of Wnt pathway in the pathobiology of ischemic and hemorrhagic stroke, as well as traumatic brain injury (TBI). Furthermore, the review will present the strategies used so far to manipulate the pathway for therapeutic purposes as to highlight potential future directions.

Regulator of G-Protein Signaling 5 Maintains Brain Endothelial Cell Function in Focal Cerebral Ischemia

Background

Regulator of G‐protein signaling 5 (RGS5) is a negative modulator of G‐protein–coupled receptors. The role of RGS5 in brain endothelial cells is not known. We hypothesized that RGS5 in brain microvascular endothelial cells may be an important mediator of blood‐brain barrier function and stroke severity after focal cerebral ischemia.

Methods and Results

Using a transient middle cerebral artery occlusion model, we found that mice with global and endothelial‐specific deletion of Rgs5 exhibited larger cerebral infarct size, greater neurological motor deficits, and increased brain edema. In our in vitro models, we observed increased G_q activity and elevated intracellular Ca²⁺ levels in brain endothelial cells. Furthermore, the loss of endothelial RGS5 leads to decreased endothelial NO synthase expression and phosphorylation, relocalization of endothelial tight junction proteins, and increased cell permeability. Indeed, RGS5 deficiency leads to increased Rho‐associated kinase and myosin light chain kinase activity, which were partially reversed in our in vitro model by pharmacological inhibition of G_q, metabotropic glutamate receptor 1, and ligand‐gated ionotropic glutamate receptor.

Conclusions

Our findings indicate that endothelial RGS5 plays a novel neuroprotective role in focal cerebral ischemia. Loss of endothelial RGS5 leads to hyperresponsiveness to glutamate signaling pathways, enhanced Rho‐associated kinase– and myosin light chain kinase–mediated actin‐cytoskeleton reorganization, endothelial dysfunction, tight junction protein relocalization, increased blood‐brain barrier permeability, and greater stroke severity. These findings suggest that preservation of endothelial RGS5 may be an important therapeutic strategy for maintaining blood‐brain barrier integrity and limiting the severity of ischemic stroke.

3-Mercaptopyruvate sulfurtransferase/hydrogen sulfide protects cerebral endothelial cells against oxygen-glucose deprivation/reoxygenation-induced injury via mitoprotection and inhibition of the RhoA/ROCK pathway

3-Mercaptopyruvate sulfurtransferase (3-MST) is the major source of hydrogen sulfide (H₂S) production in the brain and participates in many physiological and pathological processes. The present study was designed to investigate the role of 3-MST-derived H₂S (3-MST/H₂S) on oxygen-glucose deprivation/reoxygenation (OGD/R) injury in cerebrovascular endothelial cells (ECs). Using cerebrovascular specimens from patients with acute massive cerebral infarction (MCI), we found abnormal morphology of the endothelium and mitochondria, as well as decreases in H₂S and 3-MST levels. In an OGD/R model of ECs, 3-mercaptopyruvate (3-MP) and l-aspartic acid (l-Asp) were used to stimulate or inhibit the production of 3-MST/H₂S. The results showed that OGD/R induced significant decreases in H₂S and 3-MST levels in both ECs and mitochondria, as well as increases in oxidative stress and mitochondrial energy imbalance. Cellular oxidative stress, destruction of mitochondrial ultrastructure, accumulation of mitochondrial reactive oxygen species (ROS), reduction of mitochondrial adenosine triphosphate (ATP) synthase activity and ATP production, and decreased mitochondrial membrane potential were all significantly ameliorated by 3-MP, whereas they were exacerbated by l-Asp pretreatment. Contrary to the effects of l-Asp, the increase in RhoA activity and expression of ROCK₁ and ROCK₂ induced by OGD/R were markedly inhibited by 3-MP pretreatment in subcellular fractions without mitochondria and mitochondrial fractions. In addition, 3-MST^-/- rat ECs displayed greater oxidative stress than 3-MST^+/+ rat ECs after OGD/R injury. These findings suggest that 3-MST/H₂S protects ECs against OGD/R-induced injury, which may be related to preservation of mitochondrial function and inhibition of the RhoA/ROCK pathway.

Role of the neurovascular unit in the process of cerebral ischemic injury

Cerebral ischemic injury exhibits both high morbidity and mortality worldwide. Traditional research of the pathogenesis of cerebral ischemic injury has focused on separate analyses of the involved cell types. In recent years, the neurovascular unit (NVU) mechanism of cerebral ischemic injury has been proposed in modern medicine. Hence, more effective strategies for the treatment of cerebral ischemic injury may be provided through comprehensive analysis of brain cells and the extracellular matrix. However, recent studies that have investigated the function of the NVU in cerebral ischemic injury have been insufficient. In addition, the metabolism and energy conversion of the NVU depend on interactions among multiple cell types, which make it difficult to identify the unique contribution of each cell type. Therefore, in the present review, we comprehensively summarize the regulatory effects and recovery mechanisms of four major cell types (i.e., astrocytes, microglia, brain-microvascular endothelial cells, and neurons) in the NVU under cerebral ischemic injury, as well as discuss the interactions among these cell types in the NVU. Furthermore, we discuss the common signaling pathways and signaling factors that mediate cerebral ischemic injury in the NVU, which may help to provide a theoretical basis for the comprehensive elucidation of cerebral ischemic injury.

Advances in the Signaling Pathways Downstream of Glial-Scar Axon Growth Inhibitors

Axon growth inhibitors generated by reactive glial scars play an important role in failure of axon regeneration after CNS injury in mature mammals. Among the inhibitory factors, chondroitin sulfate proteoglycans (CSPGs) are potent suppressors of axon regeneration and are important molecular targets for designing effective therapies for traumatic brain injury or spinal cord injury (SCI). CSPGs bind with high affinity to several transmembrane receptors, including two members of the leukocyte common antigen related (LAR) subfamily of receptor protein tyrosine phosphatases (RPTPs). Recent studies demonstrate that multiple intracellular signaling pathways downstream of these two RPTPs mediate the growth-inhibitory actions of CSPGs. A better understanding of these signaling pathways may facilitate development of new and effective therapies for CNS disorders characterized by axonal disconnections. This review will focus on recent advances in the downstream signaling pathways of scar-mediated inhibition and their potential as the molecular targets for CNS repair.

Computational systematic selectivity of the Fasalog inhibitors between ROCK-I and ROCK-II kinase isoforms in Alzheimer's disease

Human Rho-associated coiled-coil forming kinase (ROCK) is a class of essential neurokinases that consists of two structurally conserved isoforms ROCK-I and ROCK-II; they have been revealed to play distinct roles in the pathogenesis of Alzheimer's disease (AD) and other neurological disorders. Selective targeting of the two kinase isoforms with small-molecule inhibitors is a great challenge due to the surprisingly high homology in kinase domain (92 %) and the full identity in kinase active site (100 %). Here, we describe a computational protocol to systematically profile the selectivity of Fasudil and its 25 analogs (termed as Fasalogs) between the two kinase isoforms. It is suggested that the substitution of Fasudil's 1,4-diazepane moiety with rigid ring such as Ripasudil and Dimehtylfasudil would render the resulting inhibitors of ROCK-II over ROCK-I (II-o-I) selectivity, while the substitution with long, flexible group such as H-89 and BDBM92607 tends to have I-o-II selectivity. Structural analysis reveals that the inhibitor affinity is not only determined by the identical active site, but also contributed from the non-identical first and second shells of the site as well as other non-conserved kinase regions, which can indirectly influence the active site and inhibitor binding through allosteric effect. A further kinase assay basically confirms the computational findings, which also exhibits a good consistence with theoretical selectivity over 10 tested samples (Rp = 0.89). In particular, the Fasalog compounds Dimehtylfasudil and H-89 are identified as II-o-I and I-o-II selective inhibitors. They can be considered as promising lead molecular entities to develop new specific ROCK isoform-selective Fasalog inhibitors.

Hydrochloride fasudil attenuates brain injury in ICH rats

Aim

The aim of this study was to investigate the neuroprotective effects of hydrochloride fasudil (HF) in rats following intracerebral hemorrhage (ICH).

Methods

Male Wistar rats were randomly divided into four groups: normal, sham-operated, ICH, and ICH/HF. ICH was induced by injection of non-anticoagulant autologous arterial blood into the right caudate nucleus. The levels of Rho-associated protein kinase 2 (ROCK2) mRNA and protein around the site of the hematoma were measured by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA), respectively. The levels of interleukin-6 and tumor necrosis factor-α in serum were detected by ELISA. The inflammatory cells and changes in the neuronal morphology around the hematoma were visualized using hematoxylin and eosin and Nissl staining. Brain edema was measured by comparing wet and dry brain weights.

Results

Following ICH, the levels of ROCK2 were significantly increased from day 1 to day 7. The levels of ROCK2 were significantly lower in rats treated with HF than in controls. The levels of inflammatory cytokines and brain water content were significantly higher in rats treated with HF than in controls. Administration of HF significantly reduced the levels of inflammatory cytokines and brain water content from day 1 to day 7. In the acute phase of ICH, a large number of neutrophils infiltrated the perihematomal areas. In comparison with the ICH group, the ICH/HF group showed markedly fewer infiltrating neutrophils on day 1. Nissl staining showed that ICH caused neuronal death and loss of neurons in the perihematomal areas at all time points and that treatment with HF significantly attenuated neuronal loss.

Conclusions

HF exerts neuroprotective effects in ICH rats by inhibiting the expression of ROCK2, reducing neutrophil infiltration and production of inflammatory cytokines, decreasing brain edema, and attenuating loss of neurons.

Acute lung injury: The therapeutic role of Rho kinase inhibitors

Acute lung injury (ALI) is a pulmonary illness with high rates of mortality and morbidity. Rho GTPase and its downstream effector, Rho kinase (ROCK), have been demonstrated to be involved in cell adhesion, motility, and contraction which can play a role in ALI. The electronic databases of Google Scholar, Scopus, PubMed, and Web of Science were searched to obtain relevant studies regarding the role of the Rho/ROCK signaling pathway in the pathophysiology of ALI and the effects of specific Rho kinase inhibitors in prevention and treatment of ALI. Upregulation of the RhoA/ROCK signaling pathway causes an increase of inflammation, immune cell migration, apoptosis, coagulation, contraction, and cell adhesion in pulmonary endothelial cells. These effects are involved in endothelium barrier dysfunction and edema, hallmarks of ALI. These effects were significantly reversed by Rho kinase inhibitors. Rho kinase inhibition offers a promising approach in ALI [ARDS] treatment.

Targeting Rho-associated coiled-coil forming protein kinase (ROCK) in cardiovascular fibrosis and stiffening

Introduction: Pathological cardiac fibrosis, through excessive extracellular matrix protein deposition from fibroblasts and pro-fibrotic immune responses and vascular stiffening is associated with most forms of cardiovascular disease. Pathological cardiac fibrosis and stiffening can lead to heart failure and arrythmias and vascular stiffening may lead to hypertension. ROCK, a serine/threonine kinase downstream of the Rho-family of GTPases, may regulate many pro-fibrotic and pro-stiffening signaling pathways in numerous cell types.Areas covered: This article outlines the molecular mechanisms by which ROCK in fibroblasts, T helper cells, endothelial cells, vascular smooth muscle cells, and macrophages mediate fibrosis and stiffening. We speculate on how ROCK could be targeted to inhibit cardiovascular fibrosis and stiffening.Expert opinion: Critical gaps in knowledge must be addressed if ROCK inhibitors are to be used in the clinic. Numerous studies indicate that each ROCK isoform may play differential roles in regulating fibrosis and may have opposing roles in specific tissues. Future work needs to highlight the isoform- and tissue-specific contributions of ROCK in fibrosis, and how isoform-specific ROCK inhibitors in murine models and in clinical trials affect the pathophysiology of cardiac fibrosis and stiffening. This could progress knowledge regarding new treatments for heart failure, arrythmias and hypertension and the repair processes after myocardial infarction.

RhoA/ROCK pathway: implication in osteoarthritis and therapeutic targets

Ras homolog gene family, member A (RhoA) and its downstream effector Rho-associated protein kinase (ROCK) play important roles in multiple cellular processes, but abnormal activation of this pathway have been reported to be involved in various types of diseases, including osteoarthritis (OA). This article focused to review the RhoA/ROCK association and its functional role in OA development, and possible therapeutics of OA by targeting this pathway. We have explored the databases like Pubmed, Google Scholar, Web of Science and SCOPUS, and collected the papers on Rho/ROCK and their relationship with OA, and reviewed comprehensively. Studies revealed that the abnormal activation of RhoA/ROCK signaling is involved in early phase response to abnormal mechanical stimuli, which is thought to be a contributory factor to OA progression. RhoA/ROCK interacts with OA pathological factors and induces cartilage degeneration through the degradation of chondrocyte extracellular matrix (ECM). As the RhoA/ROCK activity can affect bone formation by triggering cartilage degradation, it may represent a possible therapeutic target to treat OA. Interestingly, several pharmaceutical companies are investing in the development of RhoA/ROCK inhibitors for the treatment of OA. However, a few in vivo experiments have been successfully conducted to demonstrate the potential value of RhoA/ROCK pathway inhibition in the treatment of OA. This review provides an insight into the functional role of Rho/ROCK pathway, and indicates that targeting this pathway might be promising in future OA treatment.

miR‑335 promotes stress granule formation to inhibit apoptosis by targeting ROCK2 in acute ischemic stroke

Under harmful environmental conditions, stress granules (SGs), macromolecular aggregates that are associated with cell survival and death, are produced in the eukaryotic cytoplasm. However, whether and how microRNAs (miRNAs/miRs) modulate SG formation induced by acute ischemic stroke has not been investigated. In the present study, a rat model of middle cerebral artery occlusion (MCAO) was utilized and miRNA array profiling and reverse transcription‑quantitative polymerase chain reaction were performed. The results revealed that miR‑335 was downregulated during acute ischemic stroke, which was concomitant with reduced SG formation, enhanced apoptosis levels and increased Rho associated protein kinase 2 (ROCK2) expression. In the MCAO rat and serum‑free cell models, miR‑335 treatment upregulated SG formation, alleviated the ischemia‑induced infarction, and decreased ROCK2 protein expression and apoptosis levels. By contrast, when compared with miR‑335 treatment, the inhibition of miR‑335 resulted in reduced SG formation and higher ROCK2 expression and apoptosis levels. Target prediction analysis and luciferase 3'‑untranslated region reporter assay identified ROCK2 as the direct target of miR‑335. Furthermore, ROCK2 silencing enhanced SG formation and attenuated the level of apoptosis in the serum‑free cell model. In addition, ROCK2 silencing markedly inhibited the effect of miR‑335 on SG formation and apoptosis levels. Unexpectedly, the phosphorylation of T‑cell intracellular antigen‑1 was significantly inhibited by miR‑335 in the MCAO rat model, which provides a reasonable explanation for the promotional effect of miR‑335 on SG formation by specifically targeting ROCK2. In conclusion, these results demonstrate that miR‑335 promotes SG formation and inhibits apoptosis by reducing ROCK2 expression in acute ischemic stroke, which provides a possible therapeutic target for brain injury.