New Mechanisms to Prevent Heart Failure with Preserved Ejection Fraction Using Glucagon-like Peptide-1 Receptor Agonism (GLP-1 RA) in Metabolic Syndrome and in Type 2 Diabetes: A Review

This review examines the impact of obesity on the pathophysiology of heart failure with preserved ejection fraction (HFpEF) and focuses on novel mechanisms for HFpEF prevention using a glucagon-like peptide-1 receptor agonism (GLP-1 RA). Obesity can lead to HFpEF through various mechanisms, including low-grade systemic inflammation, adipocyte dysfunction, accumulation of visceral adipose tissue, and increased pericardial/epicardial adipose tissue (contributing to an increase in myocardial fat content and interstitial fibrosis). Glucagon-like peptide 1 (GLP-1) is an incretin hormone that is released from the enteroendocrine L-cells in the gut. GLP-1 reduces blood glucose levels by stimulating insulin synthesis, suppressing islet α-cell function, and promoting the proliferation and differentiation of β-cells. GLP-1 regulates gastric emptying and appetite, and GLP-1 RA is currently indicated for treating type 2 diabetes (T2D), obesity, and metabolic syndrome (MS). Recent evidence indicates that GLP-1 RA may play a significant role in preventing HFpEF in patients with obesity, MS, or obese T2D. This effect may be due to activating cardioprotective mechanisms (the endogenous counter-regulatory renin angiotensin system and the AMPK/mTOR pathway) and by inhibiting deleterious remodeling mechanisms (the PKA/RhoA/ROCK pathway, aldosterone levels, and microinflammation). However, there is still a need for further research to validate the impact of these mechanisms on humans.

Sildenafil improves hemodynamic changes caused by acute pulmonary embolism by inhibiting Rho kinase activity

OBJECTIVE

This study examined the effects of sildenafil on acute pulmonary embolism (APE) using a rat model.

METHODS

Sprague-Dawley rats were randomly divided into the sham, pulmonary thromboembolism (PTE), and sildenafil groups. The sham and PTE groups received normal saline once daily via gavage for 14 consecutive days, whereas the sildenafil group received sildenafil (0.5 mg/kg/day) once daily via gavage for 14 consecutive days. Autologous emboli were prepared from blood samples collected from the left femoral artery of rats in each group on day 13, and autologous emboli were injected into the jugular vein cannula of rats in the PTE and sildenafil groups on day 14. Sham-treated rats received the same volume of saline. Right systolic ventricular pressure (RVSP) and mean pulmonary arterial pressure (MPAP) were used to assess pulmonary embolism, and western blotting and enzyme-linked immunosorbent assay were used to detect relevant markers.

RESULTS

The Rho kinase signaling pathway was significantly activated in rats with APE, and sildenafil significantly inhibited this activation.

CONCLUSIONS

Sildenafil protected against APE through inhibiting Rho kinase activity, thereby reducing pulmonary vasoconstriction and decreasing elevated pulmonary arterial pressure. These findings might provide new ideas for the clinical treatment of acute pulmonary thromboembolism.

Fasudil-modified macrophages reduce inflammation and regulate the immune response in experimental autoimmune encephalomyelitis

Multiple sclerosis is characterized by demyelination and neuronal loss caused by inflammatory cell activation and infiltration into the central nervous system. Macrophage polarization plays an important role in the pathogenesis of experimental autoimmune encephalomyelitis, a traditional experimental model of multiple sclerosis. This study investigated the effect of Fasudil on macrophages and examined the therapeutic potential of Fasudil-modified macrophages in experimental autoimmune encephalomyelitis. We found that Fasudil induced the conversion of macrophages from the pro-inflammatory M1 type to the anti-inflammatory M2 type, as shown by reduced expression of inducible nitric oxide synthase/nitric oxide, interleukin-12, and CD16/32 and increased expression of arginase-1, interleukin-10, CD14, and CD206, which was linked to inhibition of Rho kinase activity, decreased expression of toll-like receptors, nuclear factor-κB, and components of the mitogen-activated protein kinase signaling pathway, and generation of the pro-inflammatory cytokines tumor necrosis factor-α, interleukin-1β, and interleukin-6. Crucially, Fasudil-modified macrophages effectively decreased the impact of experimental autoimmune encephalomyelitis, resulting in later onset of disease, lower symptom scores, less weight loss, and reduced demyelination compared with unmodified macrophages. In addition, Fasudil-modified macrophages decreased interleukin-17 expression on CD4+ T cells and CD16/32, inducible nitric oxide synthase, and interleukin-12 expression on F4/80+ macrophages, as well as increasing interleukin-10 expression on CD4+ T cells and arginase-1, CD206, and interleukin-10 expression on F4/80+ macrophages, which improved immune regulation and reduced inflammation. These findings suggest that Fasudil-modified macrophages may help treat experimental autoimmune encephalomyelitis by inducing M2 macrophage polarization and inhibiting the inflammatory response, thereby providing new insight into cell immunotherapy for multiple sclerosis.

Recent advances in the development of Rho kinase inhibitors (2015-2021)

Rho-associated coiled-coil kinases (ROCKs) are key downstream effectors of small GTPases. ROCK plays a central role in diverse cellular events with accumulating evidence supporting the concept that ROCK is important in tumor development and progression. Numerous ROCK inhibitors have been investigated for their therapeutic potential in the treatment of cancers. In this article, we review recent research progress on ROCK inhibitors, especially those with potential for the treatment of cancers, reported in the literature from 2015 to 2021. Most ROCK inhibitors show potent in vitro and in vivo antitumor activities and have potential in the treatment of cancers.

Rho-Kinase Inhibitors as Emerging Targets for Glaucoma Therapy

Glaucoma, the leading cause of irreversible blindness worldwide, is a chronic and progressive optic neuropathy characterized by damage to the optic and retinal nerve fiber layers, which can lead to permanent loss of peripheral or central vision. Reduction of intraocular pressure (IOP) is the only known modifiable risk factor for preventing and treating glaucoma. Rho kinase (ROCK) inhibitors are a new class of glaucoma drugs with a novel mechanism of action and good safety profile. They exert neuroprotective effects, act on the trabecular tissue, increase the outflow of aqueous humor, and reduce intraocular pressure. However, they also cause local adverse reactions, including common conjunctival congestion and subconjunctival bleeding; however, most are self-limiting and temporary. Netarsudil (0.02%), a ROCK inhibitor, relaxes the trabecular meshwork, increases the outflow of aqueous humor, reduces scleral venous pressure, and directly decreases IOP. Conjunctival congestion can be reduced if netarsudil is administered at night. The combination of these medications is always more effective than the single drug. Ripasudil (0.4%), another ROCK inhibitor, also lowers IOP; however, conjunctival hyperemia is the most common adverse drug reaction. The purpose of this review is to summarize the effects and adverse reactions of ROCK inhibitors in the experimental trial stage and in clinical treatment in recent years, providing suggestions for future clinical drug use, and research and development to reduce the side effects of these drugs, maximize the potential for reducing IOP, and improve the therapeutic effect.

Calcium handling coupled to the endothelin ETA and ETB receptor-mediated vasoconstriction in resistance arteries: Differential regulation by PI3K, PKC and RhoK

Abnormal endothelin-1 (ET-1) activity is involved in the pathogenesis of vascular diseases such as essential and pulmonary arterial hypertension, coronary artery disease, and cerebrovascular disease, blockade of ET receptors having shown efficacy in clinical assays and experimental models of hypertension. Augmented Ca2+ influx and changes in Ca2+ sensitization associated with arterial vasoconstriction underlie increased systemic vascular resistance in hypertension. Since peripheral resistance arteries play a key role in blood pressure regulation, we aimed to determine here the specific Ca2+ signaling mechanisms linked to the ET receptor-mediated vasoconstriction in resistance arteries and their selective regulation by protein kinase C (PKC), Rho kinase (RhoK), the phosphatidylinositol 3-kinase (PI3K) and the mitogen-activated protein kinase (MAPK). ET-1-induced contraction was mediated by the endothelin ETA receptor with a minor contribution of vascular smooth muscle (VSM) endothelin ETB receptors. ET receptor activation elicited Ca2+ mobilization from intracellular stores, extracellular Ca2+ influx and Ca2+ sensitization associated with contraction in resistance arteries. Vasoconstriction induced by ET-1 was largely dependent on activation of canonical transient receptor potential channel 3 (TRPC3) and extracellular Ca2+ influx through nifedipine-sensitive voltage-dependent Ca2+ channels. PI3K inhibition reduced intracellular Ca2+ mobilization and Ca2+ entry without altering vasoconstriction elicited by ET-1, while PKC has dual opposite actions by enhancing Ca2+ influx associated with contraction, and by inhibiting Ca2+ release from intracellular stores. RhoK was a major determinant of the enhanced sensitivity of the contractile filaments underlying ET-1 vasoconstriction, with also a modulatory positive action on Ca2+ influx and intracellular Ca2+ release. Augmented RhoK and PKC activities are involved in vascular dysfunction in hypertension and vascular complications of insulin-resistant states, and these kinases are thus potential pharmacological targets in vascular diseases in which the ET pathway is impaired.

TNF-α evokes blood-brain barrier dysfunction through activation of Rho-kinase and neurokinin 1 receptor

Ischaemic stroke, accompanied by neuroinflammation, impairs blood-brain barrier (BBB) integrity through a complex mechanism involving activation of both RhoA/Rho kinase/myosin light chain-2 and neurokinin 1 receptor (NK1R). Using an in vitro model of human BBB composed of brain microvascular endothelial cells (BMEC), astrocytes and pericytes, this study examined the potential contributions of these elements to BBB damage induced by elevated availability of pro-inflammatory cytokine, TNF-α. Treatment of human BMECs with TNF-α significantly enhanced RhoA activity and the protein expressions of Rho kinase and phosphorylated Ser19MLC-2 while decreasing that of NK1R. Pharmacological inhibition of Rho kinase by Y-27632 and NK1R by CP96345 neutralised the disruptive effects of TNF-α on BBB integrity and function as ascertained by reversal of decreases in transendothelial electrical resistance and increases in paracellular flux of low molecular weight permeability marker, sodium fluorescein, respectively. Suppression of RhoA activation, mitigation of actin stress fibre formation and restoration of plasma membrane localisation of tight junction protein zonula occludens-1 appeared to contribute to the barrier-protective effects of both Y-27632 and CP96345. Attenuation of TNF-α-mediated increases in NK1R protein expression in BMEC by Y-27632 suggests that RhoA/Rho kinase pathway acts upstream to NK1R. In conclusion, specific inhibition of Rho kinase in cerebrovascular conditions, accompanied by excessive release of pro-inflammatory cytokine TNF-α, helps preserve endothelial cell morphology and inter-endothelial cell barrier formation and may serve as an important therapeutic target.

TXA2 mediates LPA1-stimulated uterine contraction in late pregnant mouse

Lysophosphatidic acid (LPA) is known to increase uterine contraction in the estrus cycle and early pregnancy, however, the effect of LPA in late pregnant uterus and its mechanisms are not clear. In the present study, we show the LPA receptor subtypes expressed and the mechanism of LPA-induced contractions in late pregnant mouse uterus. We determined the relative mRNA expression of LPA receptor genes by quantitative PCR and elicited log concentration-response curves to oleoyl-L-α-LPA by performing tension experiments in the presence and absence of nonselective and selective receptor antagonists and inhibitors of the TXA2 pathway. LPA1 was the most highly expressed receptor subtype in the late pregnant mouse uterus and LPA1/2/3 agonist (Oleoyl-L-α LPA) elicited increased contractions in this tissue that had lesser efficacy compared to oxytocin. LPA1/3 antagonist, Ki-16425, and a potent LPA1 antagonist (AM-095) significantly inhibited the LPA-induced contractions. Further, the nonselective COX inhibitor, indomethacin, and potent thromboxane A2 synthase inhibitor, furegrelate significantly impaired LPA-induced contractions. Moreover, selective thromboxane receptor (TP) antagonist, SQ-29548, and Rho kinase inhibitor, Y-27632 almost eliminated LPA-induced uterine contractions. LPA1 stimulation elicits contractions in the late pregnant mouse uterus using the contractile prostanoid, TXA2 and may be targeted to induce labor in uterine dysfunctions/ dystocia.

Rho kinase inhibitors ameliorate cognitive impairment in a male mouse model of methamphetamine-induced schizophrenia

Schizophrenia (SCZ) is a severe psychiatric disorder characterized by positive symptoms, negative symptoms, and cognitive deficits. Current antipsychotic treatment in SCZ improves positive symptoms but has major side effects and little impact on negative symptoms and cognitive impairment. The pathoetiology of SCZ remains unclear, but is known to involve small GTPase signaling. Rho kinase, an effector of small GTPase Rho, is highly expressed in the brain and plays a major role in neurite elongation and neuronal architecture. This study used a touchscreen-based visual discrimination (VD) task to investigate the effects of Rho kinase inhibitors on cognitive impairment in a methamphetamine (METH)-treated male mouse model of SCZ. Systemic injection of the Rho kinase inhibitor fasudil dose-dependently ameliorated METH-induced VD impairment. Fasudil also significantly suppressed the increase in the number of c-Fos-positive cells in the infralimbic medial prefrontal cortex (infralimbic mPFC) and dorsomedial striatum (DMS) following METH treatment. Bilateral microinjections of Y-27632, another Rho kinase inhibitor, into the infralimbic mPFC or DMS significantly ameliorated METH-induced VD impairment. Two proteins downstream of Rho kinase, myosin phosphatase-targeting subunit 1 (MYPT1; Thr696) and myosin light chain kinase 2 (MLC2; Thr18/Ser19), exhibited increased phosphorylation in the infralimbic mPFC and DMS, respectively, after METH treatment, and fasudil inhibited these increases. Oral administration of haloperidol and fasudil ameliorated METH-induced VD impairment, while clozapine had little effect. Oral administration of haloperidol and clozapine suppressed METH-induced hyperactivity, but fasudil had no effect. These results suggest that METH activates Rho kinase in the infralimbic mPFC and DMS, which leads to cognitive impairment in male mice. Rho kinase inhibitors ameliorate METH-induced cognitive impairment, perhaps via the cortico-striatal circuit.

Involvement of α1B-adrenoceptors and Rho kinase in contractions of rat aorta and mouse spleen

α₁-adrenoceptors link via the G-protein Gq/G₁₁ to both Ca²⁺ entry and release from stores, but may also activate Rho kinase, which causes calcium sensitization. This study aimed to identify the subtype(s) of α₁-adrenoceptor involved in Rho kinase-mediated responses in both rat aorta and mouse spleen, tissues in which contractions involve multiple subtypes of α₁-adrenoceptor. Tissues were contracted with cumulative concentrations of noradrenaline (NA) in 0.5 log unit increments, before and in the presence of an antagonist or vehicle. Contractions produced by NA in rat aorta are entirely α₁-adrenoceptor mediated as they are competitively blocked by prazosin. The α_1A-adrenoceptor antagonist RS100329 had low potency in rat aorta. The α_1D-adrenoceptor antagonist BMY7378 antagonized contractions in rat aorta in a biphasic manner: low concentrations blocking α_1D-adrenoceptors and high concentrations blocking α_1B-adrenoceptors. The Rho kinase inhibitor fasudil (10 μM) significantly reduced aortic contractions in terms of maximum response, suggesting inhibition of α_1B-adrenoceptor mediated responses. In the mouse spleen, a tissue in which all 3 subtypes of α₁-adrenoceptor are involved in contractions to NA, fasudil (3 μM) significantly reduced both early and late components to the NA contraction, the early component involving α_1B- and α_1D-adrenoceptors, and the late component involving α_1B- and α_1A-adrenoceptors. This suggests that fasudil inhibits α_1B-adrenoceptor mediated responses. It is concluded that α_1D- and α_1B-adrenoceptors interact in rat aorta and α_1D-, α_1A- and α_1B-adrenoceptors interact in the mouse spleen to produce contractions and these interactions suggest that one of the receptors preferentially activates Rho kinase, most likely the α_1B-adrenoceptor.

Fluoride disrupts intestinal epithelial tight junction integrity through intracellular calcium-mediated RhoA/ROCK signaling and myosin light chain kinase

Fluoride is a common contaminant of groundwater and agricultural commodity, which poses challenges to animal and human health. A wealth of research has demonstrated its detrimental effects on intestinal mucosal integrity; however, the underlying mechanisms remain obscure. This study aimed to investigate the role of the cytoskeleton in fluoride-induced barrier dysfunction. After sodium fluoride (NaF) treatment of the cultured Caco-2 cells, both cytotoxicity and cytomorphological changes (internal vacuoles or massive ablation) were observed. NaF lowered transepithelial electrical resistance (TEER) and enhanced paracellular permeation of fluorescein isothiocyanate dextran 4 (FD-4), indicating Caco-2 monolayers hyperpermeability. In the meantime, NaF treatment altered both the expression and distribution of the tight junction protein ZO-1. Fluoride exposure increased myosin light chain II (MLC2) phosphorylation and triggered actin filament (F-actin) remodeling. While inhibition of myosin II by Blebbistatin blocked NaF-induced barrier failure and ZO-1 discontinuity, the corresponding agonist Ionomycin had effects comparable to those of fluoride, suggesting that MLC2 serves as an effector. Given the mechanisms upstream of p-MLC2 regulation, further studies demonstrated that NaF activated RhoA/ROCK signaling pathway and myosin light chain kinase (MLCK), strikingly increasing the expression of both. Pharmacological inhibitors (Rhosin, Y-27632 and ML-7) reversed NaF-induced barrier breakdown and stress fiber formation. The role of intracellular calcium ions ([Ca²⁺]_i) in NaF effects on Rho/ROCK pathway and MLCK was investigated. We found that NaF elevated [Ca²⁺]_i, whereas chelator BAPTA-AM attenuated increased RhoA and MLCK expression as well as ZO-1 rupture, thus, restoring barrier function. Collectively, abovementioned results suggest that NaF induces barrier impairment via Ca²⁺-dependent RhoA/ROCK pathway and MLCK, which in turn triggers MLC2 phosphorylation and rearrangement of ZO-1 and F-actin. These results provide potential therapeutic targets for fluoride-induced intestinal injury.

Injury to Cone Synapses by Retinal Detachment: Differences from Rod Synapses and Protection by ROCK Inhibition

Attachment of a detached retina does not always restore vision to pre-injury levels, even if the attachment is anatomically successful. The problem is due in part to long-term damage to photoreceptor synapses. Previously, we reported on damage to rod synapses and synaptic protection using a Rho kinase (ROCK) inhibitor (AR13503) after retinal detachment (RD). This report documents the effects of detachment, reattachment, and protection by ROCK inhibition on cone synapses. Conventional confocal and stimulated emission depletion (STED) microscopy were used for morphological assessment and electroretinograms for functional analysis of an adult pig model of RD. RDs were examined 2 and 4 h after injury or two days later when spontaneous reattachment had occurred. Cone pedicles respond differently than rod spherules. They lose their synaptic ribbons, reduce invaginations, and change their shape. ROCK inhibition protects against these structural abnormalities whether the inhibitor is applied immediately or 2 h after the RD. Functional restoration of the photopic b-wave, indicating cone-bipolar neurotransmission, is also improved with ROCK inhibition. Successful protection of both rod and cone synapses with AR13503 suggests this drug will (1) be a useful adjunct to subretinal administration of gene or stem cell therapies and (2) improve recovery of the injured retina when treatment is delayed.

Targeting Rho kinase to restore endothelial barrier function following vascular scaffold implantation

Vascular scaffold implantation induces injury to the intimal layer and causes discontinuity of the regenerated endothelial monolayer, compromising barrier integrity, increasing permeability, and allowing the transmigration of leukocytes and lipoproteins into the subendothelial space. Mechanical vascular wall stretching triggers Ras homolog family member A (RhoA)/Rho kinase-mediated actomyosin contractility and destabilization of adherens junctions, leading to endothelial barrier dysfunction. Assembly of intercellular adhesion and actin cytoskeletal organization of interendothelial junctions are controlled by downregulation of RhoA guanosine triphosphatase (GTPase)-mediated barrier-disruptive activity and upregulation of repressor-activator protein 1 (Rap1) and Ras-related C3 botulinum toxin substrate 1 (Rac1) GTPase-mediated cytoskeletal reorganization, leading to endothelial barrier stabilization. This review highlights the involvement of Rho GTPases in the disruption of endothelial barrier integrity following vascular scaffold implantation and the targeting of downstream Rho-associated protein kinases, which signal the network to restore endothelial barrier integrity and stability.

Phthalazinone-based lactams and cyclic ureas as ROCK2 selective inhibitors

Derivatives of lactam, cyclic urea and carbamate were explored as aniline amide replacements in a series of phthalazinone-based ROCK inhibitors. Potent ROCK2 inhibitors such as 22 were identified with excellent overall kinase selectivity as well as good isoform selectivity over ROCK1.

Inhibition of IL-6 signaling prevents serum-induced umbilical cord artery dysfunction from patients with severe COVID-19

Coronavirus disease 2019 (COVID-19) infection has a negative impact on the cytokine profile of pregnant women. Increased levels of proinflammatory cytokines seem to be correlated with the severity of the disease, in addition to predisposing to miscarriage or premature birth. Proinflammatory cytokines increase the generation of reactive oxygen species (ROS). It is unclear how interleukin-6 (IL-6) found in the circulation of patients with severe COVID-19 might affect gestational health, particularly concerning umbilical cord function. This study tested the hypothesis that IL-6 present in the circulation of women with severe COVID-19 causes umbilical cord artery dysfunction by increasing ROS generation and activating redox-sensitive proteins. Umbilical cord arteries were incubated with serum from healthy women and women with severe COVID-19. Vascular function was assessed using concentration-effect curves to serotonin in the presence or absence of pharmacological agents, such as tocilizumab (antibody against the IL-6 receptor), tiron (ROS scavenger), ML171 (Nox1 inhibitor), and Y27632 (Rho kinase inhibitor). ROS generation was assessed by the dihydroethidine probe and Rho kinase activity by an enzymatic assay. Umbilical arteries exposed to serum from women with severe COVID-19 were hyperreactive to serotonin. This effect was abolished in the presence of tocilizumab, tiron, ML171, and Y27632. In addition, serum from women with severe COVID-19 increased Nox1-dependent ROS generation and Rho kinase activity. Increased Rho kinase activity was abolished by tocilizumab and tiron. Serum cytokines in women with severe COVID-19 promote umbilical artery dysfunction. IL-6 is key to Nox-linked vascular oxidative stress and activation of the Rho kinase pathway.

Discovery and Preclinical Development of Novel Intraocular Pressure-Lowering Rho Kinase Inhibitor: Corticosteroid Conjugates

Purpose: A new class of ocular steroids designed to mitigate steroid-induced intraocular pressure (IOP) elevation while maintaining anti-inflammatory activity was developed. Herein is described the discovery and preclinical characterization of ROCK'Ster compound 1. Methods: Codrugs consisting of a Rho kinase inhibitor (ROCKi) and a corticosteroid were synthesized. Compounds were initially screened in vitro for ROCKi activity and anti-inflammatory activity against the proinflammatory interleukin 23 and bacterial lipopolysaccharide (LPS) pathways. Selected compounds were then screened for solubility, chemical stability, and ex vivo corneal metabolism. Lead compound 1 was evaluated for IOP lowering in the Dutch Belted rabbit and for anti-inflammatory efficacy in both a postcataract surgery model and an allergic eye disease (AED) mouse model. Results: Several ROCK'Sters were found to be potent inhibitors of ROCK (K_is < 50 nM), have high anti-inflammatory activity in vitro (IC₅₀s < 50 nM), display sufficient stability in topical ophthalmic formulations, and have a moderate rate of corneal metabolism. Compound 1 (0.1% and 0.25%, quater in die [QID]-4 times a day) demonstrated IOP-lowering capability without inducing hyperemia in our rabbit model. When compared with the marketed steroids, Durezol^® and Pred Forte^®, compound 1 (0.1%, 0.25%) demonstrated noninferiority in clinical scoring in a rabbit model of inflammation after surgery. In addition, anti-inflammatory outcomes were observed with compound 1 (0.1%) relative to Lotemax^® or vehicle control in an AED mouse model. Conclusion: ROCK'Ster compound 1 is a novel compound suitable for topical ocular dosing that possesses IOP-lowering capability along with similar anti-inflammatory activity compared with marketed steroids.

ROCK (RhoA/Rho Kinase) Activation in Atrial Fibrillation: Molecular Pathways and Clinical Implications

Among the complex mechanisms of AF pathogenesis, intracellular calcium overload and oxidative stress play a major role, both triggered by inflammatory processes. The additional basic event taking place in AF is atrial fibrotic remodeling, again triggered by oxidative stress, which is determined by connexins rearrangement and differentiation of fibroblasts into active collagensecreting myofibroblasts. RhoA/ROCK system is the final pathway of a wide spectrum of molecular effectors such as Angiotensin II, platelet-derived growth factor, connective tissue growth factor and transforming growth factor β, that overall determine calcium dysregulation and pro-fibrotic remodeling. Both in experimental and clinical studies, RhoA/ROCK activation has been linked to superoxide ion production, fibrotic remodeling and connexins rearrangement, with important consequences for AF pathogenesis. ROCK pathway inhibition may therefore be a therapeutic or preventive target for special AF subgroups of patients.

Nanoarchitectonics for Photo-Controlled Intracellular Drug Release in Immune Modulation

Local stimuli differentiate monocytes into M2-like macrophages that mechanistically drive the pathologies in cancer and age-related macular degeneration (AMD). A photo-controlled nanodrug that halts macrophage polarization through Rho-associated kinase (ROCK) inhibition was developed. A small-molecule ROCK inhibitor, fasudil, was conjugated to a photo-responsive group and a short poly(ethylene glycol) (PEG) chain. This resulted in the novel amphiphilic prodrug, PEG-2-(4'-(di(prop-2-yn-1-yl)amino)-4-nitro-[1,1'-biphenyl]-yl)propan-1-ol (PANBP)-Fasudil, that spontaneously formed micelles. Ultraviolet (UV) irradiation of PEG-PANBP-Fasudil nanoparticles rapidly released fasudil. For visualization of linker degradation, a reporter nanoprobe was synthesized, in which 2-Me-4-OMe TokyoGreen (TG), a fluorophore that does not fluoresce in conjugation, was incorporated. Irradiation of nanoprobe-laden monocytes activated the reporter fluorophore. Cytokine stimulation differentiated monocytes into macrophages, while UV irradiation prevented polarization of PEG-PANBP-Fasudil nanoparticle-laden monocytes. Nanoarchitectonics-based design opens new possibilities for intracellular drug delivery and precise spatiotemporal immune cell modulation toward the development of new therapies.

[Reduced oxidative stress in ADPKD patients treated with tolvaptan]

Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent monogenic kidney disease. It causes hypertension and progressive renal failure, both strictly linked to oxidative stress (OxSt). Treatment with tolvaptan is a consolidate option which slows renal deterioration rate, although the molecular mechanisms involved are not fully clarified. We evaluated the OxSt state in tolvaptan-treated ADPKD patients, untreated patients and healthy subjects. OxSt was assessed in 9 patients for each group as mononuclear cell protein expression, MYPT-1 phosphorylation state (Western blot) and heme oxygenase (HO-1) (ELISA). p22 phox protein expression was lower in tolvaptan treated ADPKD and controls compared to untreated patients: 0.86 ±0.15 d.u. p=0.015; 0.53 ±0.11, p<0.001; 1.42 ±0.11 respectively. The same was observed for phosphorylated MYPT-1: 0.68 ±0.09, p=0.013 and vs 0.47 ±0.13, p<0.001, 0.96 ±0.28, while HO-1 of untreated patients was significantly lower compared to treated and controls: 5.33 ±3.34 ng/mL, 2.08 ±0.79, p=0.012, 1.97 ±1.22, p=0.012. Tolvaptan-treated ADPKD patients have reduced OxSt, which might contribute to slowing down the loss of renal function.

Phase 1 Studies to Evaluate the Food Effect and Relative Bioavailability of Tablet and Capsule Formulations of Belumosudil in Healthy Adult Subjects

Belumosudil is a selective Rho-associated coiled-coil containing protein kinase 2 inhibitor. A capsule formulation was used during early clinical development of belumosudil; it was later replaced by a tablet formulation, which mimicked the capsule's release properties and facilitated manufacturing scalability. To assess belumosudil's pharmacokinetics, including potential food effects, and evaluate the relative bioavailability of the 2 formulations, 2 phase 1 clinical trials were conducted. Administration of both belumosudil tablets and capsules with food increased exposure ≈2× as compared to the fasted state and delayed time to maximum concentration by 0.5 hour, indicating a decrease in the rate but increase in the extent of absorption with fed administration. Relative bioavailability was slightly higher when belumosudil was administered as tablets vs capsules, although the difference was not clinically meaningful. Safety and tolerability were generally consistent with the known safety profile of belumosudil. The results of these studies support administration of belumosudil with food.

Rho Kinase regulates neutrophil NET formation that is involved in UVB-induced skin inflammation

Objective: Ultraviolet B (UVB) is an important trigger of skin inflammation and lupus with leukocyte recruitment to inflamed skin. We recently reported the involvement of neutrophil NETosis in UVB-induced skin inflammation, and that NETotic nuclear envelope rupture is driven by PKCα-mediated nuclear lamin B disassembly. To address the role of Actin cytoskeleton in NETosis, we investigated the effects of Rho kinase (ROCK) and its downstream actomyosin cytoskeletal networks on PKCα nuclear translocation and NET formation, as well as their involvement in UVB-induced skin inflammation. Methods: We studied the dynamic changes of ROCK and actomyosin cytoskeletal networks during NETosis induction and their involvement in PKCα nuclear translocation. Using mice with hematopoietic-specific ROCK1 deficiency, we investigated the effects of ROCK1 deficiency on NETosis, and its involvement in UVB-induced skin inflammation. Results: Our time course studies demonstrated the dynamic changes of actin polymerization and ROCK activation, support the role of actin cytoskeleton in nuclear translocation of cytosolic PKCα in early stage of NETosis induction. Inhibition of actin polymerization or key molecules of the ROCK/MLCK/myosin pathway decreased PKCα nuclear translocation and NET formation. Genetic deficiency of ROCK1, inhibited NETosis ex vivo and in vivo, decreased extracellular display of NET-associated IL-17A, TNFα, IFNγ, and IFNα in inflamed skin, which were correlated with the ameliorated skin inflammation in UVB-irradiated mice with hematopoietic-specific ROCK1 deficiency. Conclusions: ROCK regulated NETosis through modulation of PKCα nuclear translocation via actomyosin cytoskeletal networks in neutrophils. ROCK1 deficiency ameliorated UVB-induced skin inflammation by attenuation of NETosis and NET-associated cytokines.

Morphometric Analysis of Rat Prostate Development: Roles of MEK/ERK and Rho Signaling Pathways in Prostatic Morphogenesis

The molecular mechanisms underlying prostate development can provide clues for prostate cancer research. It has been demonstrated that MEK/ERK signaling downstream of androgen-targeted FGF10 signaling directly induces prostatic branching during development, while Rho/Rho-kinase can regulate prostate cell proliferation. MEK/ERK and Rho/Rho kinase regulate myosin light chain kinase (MLCK), and MLCK regulates myosin light chain phosphorylation (MLC-P), which is critical for cell fate, including cell proliferation, differentiation, and apoptosis. However, the roles and crosstalk of the MEK/ERK and Rho/Rho kinase signaling pathways in prostatic morphogenesis have not been examined. In the present study, we used numerical and image analysis to characterize lobe-specific rat prostatic branching during postnatal organ culture and investigated the roles of FGF10-MEK/ERK and Rho/Rho kinase signaling pathways in prostatic morphogenesis. Prostates exhibited distinctive lobe-specific growth and branching patterns in the ventral (VP) and lateral (LP) lobes, while exogenous FGF10 treatment shifted LP branching towards a VP branching pattern. Treatment with inhibitors of MEK1/2, Rho, Rho kinase, or MLCK significantly inhibited VP growth and blocked branching morphogenesis, further supporting critical roles for MEK/ERK and Rho/Rho kinase signaling pathways in prostatic growth and branching during development. We propose that MLCK-regulated MLC-P may be a central downstream target of both signaling pathways in regulating prostate morphogenesis.

Conditional deletion of ROCK2 induces anxiety-like behaviors and alters dendritic spine density and morphology on CA1 pyramidal neurons

Rho-associated kinase isoform 2 (ROCK2) is an attractive drug target for several neurologic disorders. A critical barrier to ROCK2-based research and therapeutics is the lack of a mouse model that enables investigation of ROCK2 with spatial and temporal control of gene expression. To overcome this, we generated ROCK2fl/fl mice. Mice expressing Cre recombinase in forebrain excitatory neurons (CaMKII-Cre) were crossed with ROCK2fl/fl mice (Cre/ROCK2fl/fl), and the contribution of ROCK2 in behavior as well as dendritic spine morphology in the hippocampus, medial prefrontal cortex (mPFC), and basolateral amygdala (BLA) was examined. Cre/ROCK2fl/fl mice spent reduced time in the open arms of the elevated plus maze and increased time in the dark of the light-dark box test compared to littermate controls. These results indicated that Cre/ROCK2fl/fl mice exhibited anxiety-like behaviors. To examine dendritic spine morphology, individual pyramidal neurons in CA1 hippocampus, mPFC, and the BLA were targeted for iontophoretic microinjection of fluorescent dye, followed by high-resolution confocal microscopy and neuronal 3D reconstructions for morphometry analysis. In dorsal CA1, Cre/ROCK2fl/fl mice displayed significantly increased thin spine density on basal dendrites and reduced mean spine head volume across all spine types on apical dendrites. In ventral CA1, Cre/ROCK2fl/fl mice exhibited significantly increased spine length on apical dendrites. Spine density and morphology were comparable in the mPFC and BLA between both genotypes. These findings suggest that neuronal ROCK2 mediates spine density and morphology in a compartmentalized manner among CA1 pyramidal cells, and that in the absence of ROCK2 these mechanisms may contribute to anxiety-like behaviors.

Exploring the therapeutic promise of targeting Rho kinase in rheumatoid arthritis

Rheumatoid arthritis (RA) is a prevalent systemic autoimmune disease caused by dysregulated inflammatory reactions, T lymphocyte invasion into the joints, and articular thickening. Immune cells, primarily tumor necrosis factor-alpha (TNF-α) and chemokines (interleukin or IL-1), which are predominantly generated by activated macrophages cells, have also been involved with the pathogenesis of rheumatoid arthritis. Rho GTPases are integral factors of biochemical cascades utilized by antigens, and also by cellular receptors, cytokines, and chemokines, to modulate inflammatory reactions, according to growing data. The Rho family is a group of G proteins that govern a variety of biological and physiological activities such as mobility, actin stress fiber production, growth, and polarity. Research suggests that the Rho A and Rho-associated coiled-coil kinase (ROCK) regulatory cascade could be essential in several autoimmune conditions, including RA. ROCK is activated in the synovial of rheumatoid arthritis patients, while the blocking of ROCK with fasudil could also decrease IL-6, TNF-α, and IL-1. This review covers current developments in understanding the overactivation of Rho enzyme activity in RA suppressed by ROCK inhibitors which can be utilized for the treatment of autoimmune disease. We offer an outline of the function of ROCK inhibitors in immune cells and discuss findings which emphasize the rising participation of this category of kinases within the pathological process of autoimmune disorders. Assuming the potential ability of ROCK as a therapeutic, we define approaches that might be used to inhibit Rho kinase activity in rheumatoid disorders.

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.

Vascular Stiffening Mediated by Rho-Associated Coiled-Coil Containing Kinase Isoforms

Background

The pathogenesis of vascular stiffening and hypertension is marked by non‐compliance of vessel wall because of deposition of collagen fibers, loss of elastin fibers, and increased vascular thickening. Rho/Rho‐associated coiled‐coil containing kinases 1 and 2 (ROCK1 and ROCK2) have been shown to regulate cellular contraction and vascular remodeling. However, the role of ROCK isoforms in mediating pathogenesis of vascular stiffening and hypertension is not known.

Methods and Results

Hemizygous Rock mice (Rock1^+/− and Rock2^+/−) were used to determine the role of ROCK1 and ROCK2 in age‐related vascular dysfunction. Both ROCK activity and aortic stiffness increased to a greater extent with age in wild‐type mice compared with that of Rock1^+/− and Rock2^+/− mice. As a model for age‐related vascular stiffening, we administered angiotensin II (500 ng/kg per minute) combined with nitric oxide synthase inhibitor, L‐N^ω‐nitroarginine methyl ester (0.5 g/L) for 4 weeks to 12‐week‐old male Rock1^+/− and Rock2^+/− mice. Similar to advancing age, angiotensin II/L‐N^ω‐nitroarginine methyl ester caused increased blood pressure, aortic stiffening, and vascular remodeling, which were attenuated in Rock2^+/−, and to a lesser extent, Rock1^+/− mice. The reduction of aortic stiffening in Rock2^+/− mice was accompanied by decreased collagen deposition, relatively preserved elastin content, and less aortic wall hypertrophy. Indeed, the upregulation of collagen I by transforming growth factor‐β1 or angiotensin II was greatly attenuated in Rock2^−/− mouse embryonic fibroblasts.

Conclusions

These findings indicate that ROCK1 and ROCK2 mediate both age‐related and pharmacologically induced aortic stiffening, and suggest that inhibition of ROCK2, and to a lesser extent ROCK1, may have therapeutic benefits in preventing age‐related vascular stiffening.

Silencing ROCK1 ameliorates ventilator-induced lung injury in mice by inhibiting macrophages' NLRP3 signaling

Rho kinase, including two subtypes, ROCK1 and ROCK2, controls a variety of biological processes helping coordinate the tissues response to stress and injury. Some authors believe that alveolar macrophages (AMs) play a key role in the early phase of ventilator-induced lung injury (VILI), which is closely related to the activation of NLRP3 inflammasome and NF-κB signaling. However, there is currently little known about the relationship between ROCK signaling and NLRP3 inflammasome. Accordingly, we focused on exploring the effect of ROCK for NLRP3 inflammasome, the results showed that VILI in C57BL/6 mice significantly increased NF-κB, NLRP3, ASC, caspase1 expression, and the secretion of cytokines, which was reversed by applying the ROCK Inhibitor-Y27632. Moreover, the use of AMs and mechanical stretching suggested that ROCK regulated transcriptional level of NF-κB and NLRP3 inflammasome in AMs. Specifically, we silenced the ROCK1 and ROCK2 respectively, and found that the inflammation of MH-S cells after LPS and ATP priming could be regulated by ROCK1 and ROCK2, while the NLRP3 was only dependent upon ROCK1. Meantime, the related genes of NLRP3 signal are also regulated by ROCK1. Collectively, our data suggest that silencing ROCK1 ameliorates VILI in mice in part by inhibiting AMs' NLRP3 signaling pathway.

ROCK inhibitors modulate the physical properties and adipogenesis of 3D spheroids of human orbital fibroblasts in different manners

To elucidate the pharmacological effects of Rho-associated coiled-coil containing protein kinase inhibitors (ROCK-is), ripasudil (Rip), Y27632, and KD025, on human orbital fatty tissue, the human orbital fibroblasts (HOFs) were three-dimensional (3D) cultured for 12 days. The effects of ROCK-is on the physical properties of the 3D-cultured HOF spheroids, including their sizes and physical stiffness, their adipogenesis by lipid staining, and the mRNA expression of adipogenesis-related genes, PPARγ and AP2, and extracellular matrix (ECM) including collagen (COL) 1, 4, and 6, and fibronectin were analyzed. A significant increase in the sizes, physical stiffness, lipid staining, and mRNA expression of adipogenesis-related genes, COL4 and COL6, and a decrease in COL1 expression were observed with adipogenesis (DIF+). In the presence of ROCK-is, such DIF+-induced effects were differently modulated as follows: (1) the sizes were not affected or significantly enhanced by Rip, Y27632, or KD025, (2) the physical stiffness was significantly decreased in Rip and Y27632, but was substantially increased in KD025, (3) the lipid staining was further enhanced or significantly suppressed by Rip, Y27632, or KD025, and both PPARγ and AP2 expression were significantly downregulated or upregulated by KD025 or Rip, and (4) Rip upregulated the expression of COL4, Y27632 upregulated the expression of COL1, COL4, and COL6, and KD025 upregulated the expression of COL1 and COL4. This study indicates that ROCK-is significantly and differently modulate physical properties of the 3D HOF spheroids as well as their adipogenesis.

Sphingosine 1-phosphate receptor type 2 positively regulates interleukin (IL)-4/IL-13-induced STAT6 phosphorylation

Previous reports have demonstrated that sphingosine 1-phosphate receptor type 2 (S1P₂) is involved in the activation of signal transducer and activator of transcription (STAT) 6. Additionally, the major signaling pathway of S1P₂ is the Rho-Rho kinase pathway. In this study, we examined the role of S1P₂ in STAT6 activation in a macrophage (Mφ) model using THP-1 cells differentiated with phorbol 12-myristate 13-acetate (PMA). We established S1P₂^knockout THP-1 cells using the CRISPR-Cas9 gene editing system. The PMA-treated S1P₂^knockout THP-1 Mφs showed decreases in IL-4/IL-13-induced phosphorylation of Janus-activated kinase (JAK) 1, JAK2, and STAT6 as well as mRNA expression of the M2 marker ARG1 compared with wild-type THP-1 Mφs. Pretreatment of PMA-treated THP-1 Mφs with the S1P₂ antagonist JTE-013, the Rho inhibitor Rhosin or the Rho kinase inhibitor Y27632 inhibited the IL-4/IL-13-induced increase in STAT6 phosphorylation. The expressions of suppressor of cytokine signaling 3 in the S1P₂^knockout THP-1 Mφs were higher than those in wild-type THP-1 Mφs. In addition, the protein tyrosine phosphatase inhibitor vanadate enhanced IL-4-induced STAT6 phosphorylation in the S1P₂^knockout THP-1 Mφs, suggesting that S1P₂-Rho-Rho kinase inhibited the negative regulation of STAT6. These results suggest that the S1P₂-Rho-Rho kinase pathway is necessary for full activation of STAT6 by IL-4/IL-13 in Mφs.

Design, synthesis, and biological evaluation of urea-based ROCK2 inhibitors

A series of urea-based ROCK2 inhibitors were design and synthesized. The inhibitory activity on ROCK2 was screened by enzyme-linked immunosorbent assay (ELISA). The study results showed that the urea derivatives exhibited certain ROCK2 inhibitory activity. The most potent compound 10p showed ROCK2 inhibitory activity with the IC₅₀  value of 0.03 μM. A preliminary structure-activity relationship was then summarized. The molecular docking studies showed that further optimization needs to conduct to obtain more potent ROCK inhibitors.

Sevoflurane and isoflurane inhibit KCl-induced, Rho kinase-mediated, and PI3K-participated vasoconstriction in aged diabetic rat aortas

BACKGROUND

The mechanism of volatile anesthetics on vascular smooth muscle (VSM) contraction in the setting of diabetes mellitus (DM) remains unclear. The current study was designed to determine the effects of sevoflurane (SEVO) and isoflurane (ISO) on phosphoinositide 3-kinase (PI3K) and Rho kinase (ROCK) mediated KCl-induced vasoconstriction in aged type 2 diabetic rats.

METHODS

KCl-induced (60 mM) contractions were examined in endothelium-denuded aortic rings from aged T2DM Otsuka Long-Evans Tokushima Fatty (OLETF) rats (65-70 weeks old), control age-matched nondiabetic Long-Evans Tokushima Otsuka (LETO) rats and young Wistar rats (6-8 weeks old). The effects of SEVO or ISO (1-3 minimum alveolar concentration, MAC) on KCl-induced vasoconstriction, as well as those of LY294002 (PI3K inhibitor) and Y27632 (ROCK inhibitor) were measured in aortic rings from the three groups using an isometric force transducer.

RESULTS

KCl induced rapid and continuous contraction of aortic smooth muscle in the three groups, and the contraction was more obvious in OLETF rats. SEVO and ISO inhibited KCl-induced vasoconstriction in a concentration-dependent manner and were suppressed by LY294002 (10 µM) and Y27632 (1 µM). SEVO had a stronger inhibitory effect on the aortas of young Wistar rats than ISO, especially at 2 MAC and 3 MAC (P < 0.05). In aged rats, the inhibitory effect of ISO was stronger than that of SEVO, especially OLETF rats. There was no significant difference in the effects of different concentrations of ISO on arterial contraction among the three groups (P > 0.05). The effects of 1 MAC SEVO on Wistar rats and 3 MAC SEVO on OLETF rats, however, were noticeably and significantly different (P < 0.05). Compared with the control condition, LY294002 and Y27632 had the most noticeable effect on the KCl-induced contraction of aortic rings in OLETF rats (P < 0.01).

CONCLUSION

SEVO (3 MAC), ISO (1, 2, 3 MAC), LY294002 and Y27632 have more significant inhibitory effect on the contraction of vascular smooth muscle in aged T2MD rats. The mechanism of SEVO and ISO in vascular tension in T2DM is partly due to changes in PI3K and/or Rho kinase activity.

Rho signaling inhibition mitigates lung injury via targeting neutrophil recruitment and selectin-AKT signaling

Neutrophils, the early responders of the immune system, eliminate intruders, but their over-activation can also instigate tissue damage leading to various autoimmune and inflammatory disease conditions. As approaches causing neutropenia are associated with immunodeficiency, targeting aberrant neutrophil infiltration offers an attractive strategy in neutrophil-centered diseases including acute lung injury. Rho GTPase family proteins Rho, Rac and Cdc42 play important role as regulators of chemotaxis in diverse systems. Rho inhibitors protected against lung injuries, while genetic Rho-deficiency exhibited neutrophil hyperactivity and exacerbated lung injury. These differential outcomes might be due to distinct effects on different cell types or activation/ inhibition of specific signaling pathways responsible for neutrophil polarity, migration and functions. In this study, we explored neutrophil centric effects of Rho signaling mitigation. Consistent with previous reports, Rho signaling inhibitor Y-27632 provided protection against acute lung injury, but without regulating LPS mediated systemic increase of neutrophils in the circulation. Interestingly, the adoptive transfer approach identified a specific defect in neutrophil migration capacity after Rho signaling mitigation. These defects were associated with loss of polarity and altered actin dynamics identified using time-lapse in vitro studies. Further analysis revealed a rescue of stimulation-dependent L-selectin shedding on neutrophils with Rho signaling inhibitor. Surprisingly, functional blocking of L-selectin (CD62L) led to defective recruitment of neutrophils into inflamed lungs. Further, single-cell level analyses identified MAPK signaling as downstream mechanism of Rho signaling and L-selectin mediated effects. p-AKT levels were diminished in detergent resistance membrane-associated signalosome upon Rho signaling inhibition and blockade of selectin. Moreover, inhibition of AKT signaling as well as selectin blocking led to defects in neutrophil polarity. Together, this study identified Rho-dependent distinct L-selectin and AKT signaling mediated regulation of neutrophil recruitment to inflamed lung tissue.

Emerging targets in drug discovery against neurodegenerative diseases: Control of synapsis disfunction by the RhoA/ROCK pathway

Synaptic spine morphology is controlled by the activity of Rac1, Cdc42 and RhoA, which need to be finely balanced, and in particular RhoA/ROCK prevents the formation of new protrusions by stabilizing actin formation. These processes are crucial to the maturation process, slowing the de novo generation of new spines. The RhoA/ROCK also influences plasticity processes, and selective modulation by ROCK1 of MLC-dependent actin dynamics leads to neurite retraction, but not to spine retraction. ROCK1 is also responsible for the reduction of the readily releasable pool of synaptic vesicles. These and other evidences suggest that ROCK1 is the main isoform acting on the presynaptic neuron. On the other hand, ROCK2 seems to have broad effects on LIMK/cofilin-dependent plasticity processes such as cofilin-dependent PSD changes. The RhoA/ROCK pathway is an important factor in several different brain-related pathologies via both downstream and upstream pathways. In the aggregate, these evidences show that the RhoA/ROCK pathway has a central role in the etiopathogenesis of a large group of CNS diseases, which underscores the importance of the pharmacological modulation of RhoA/ROCK as an important pathway to drug discovery in the neurodegenerative disease area. This article aims at providing the first review of the role of compounds acting on the RhoA/ROCK pathway in the control of synaptic disfunction.

Angiotensin II-Induced Vasoconstriction via Rho Kinase Activation in Pressure-Overloaded Rat Thoracic Aortas

Angiotensin II (Ang II) induces vasoconstriction through myosin light chain (MLC) kinase activation and MLC phosphatase inactivation via phosphorylation of myosin phosphatase targeting subunit 1 (MYPT1) by Rho kinase. However, the detailed mechanism underlying Rho kinase activation by Ang II is still unknown. We investigated the mechanism of Ang II-induced vasoconstriction mediated by Rho kinase in pressure-overloaded rat thoracic aortas. Pressure-overloaded rats were produced by coarctation of the suprarenal abdominal aorta in four-week-old male Wistar rats. The contractile response to Ang II was significantly enhanced in the pressure-overloaded rats. Ang II-induced vasoconstriction was attenuated by inhibitors of Rho kinase, extracellular signal-regulated kinase 1 and 2 (Erk1/2), and epidermal growth factor receptor (EGFR) in both the sham-operated and pressure-overloaded rats. The Ang II-induced vasoconstriction was attenuated by a Janus kinase 2 (JAK2) inhibitor in only the pressure-overloaded rats. The protein levels of MYPT1 and JAK2 increased only in the pressure-overloaded rat thoracic aortas. These results suggested that Ang II-induced contraction is mediated by Rho kinase activation via EGFR, Erk1/2, and JAK2 in pressure-overloaded rat thoracic aortas. Moreover, Ang II-induced contraction was enhanced in pressure-overloaded rats probably because the protein levels of MYPT1 and JAK2 increased in the thoracic aortas.

Role of RhoA/ROCK signaling in Alzheimer's disease

Rho-associated coiled-coil kinase (ROCK), a serine/threonine kinase regulated by the small GTPase RhoA, is involved in regulating cell migration, proliferation, and survival. Numerous studies have shown that the RhoA/ROCK signaling pathway can promote Alzheimer's disease (AD) occurrence. ROCK activation increases β-secretase activity and promotes amyloid-beta (Aβ) production; moreover, Aβ further activates ROCK. This is suggestive of a possible positive feedback role for Aβ and ROCK. Moreover, ROCK activation promotes the formation of neurofibrillary tangles and abnormal synaptic contraction. Additionally, ROCK activation can promote the neuroinflammatory response by activating microglia and astrocytes to release inflammatory cytokines. Therefore, ROCK is a promising drug target in AD; further, there is a need to elucidate the specific mechanism of action.

The Rho kinase signaling pathway participates in tubular mitochondrial oxidative injury and apoptosis in uric acid nephropathy

Introduction

Oxidative stress is a pathologic feature of hyperuricemia that is highly prevalent and that contributes to kidney tubular interstitial fibrosis. Rho-kinase is closely related to mitochondrial-induced oxidative stress. Herein, we designed a study to explore the expression and role of Rho-kinase in hyperuricemia nephropathy. The secondary objective was to investigate whether the Rho-kinase signaling pathway regulates hyperuricemic tubular oxidative injury and apoptosis via the mitochondrial pathway in addition to the mechanisms that are involved.

Materials and methods

HK-2 cells were divided into the following five groups: normal; uric acid (UA); UA+Fasudil; UA+ROCK1 si-RNA; and UA+sc-siRNA. Rho-kinase activity, mitochondrial oxidative injury, and apoptosis-related protein levels were measured in each group. A t-test was used to analyze the difference between groups.

Results

Myosin phosphatase target subunit 1 (MYPT1) overexpression was shown in HK-2 cells, which was caused by UA. High concentrations of UA also up-regulated Rho-kinase expression and mitochondrial and apoptosis-related protein expression, while treatment with fasudil and ROCK1 si-RNA significantly attenuated these responses.

Conclusion

The Rho-kinase signaling pathway participates in tubular mitochondrial oxidative injury and apoptosis via regulating mitochondrial dyneins/biogenic genes in UA nephropathy, which suggests that the mitochondrial pathway might be a potential therapeutic target for hyperuricemia nephropathy.

Rho-associated kinases contribute to the regulation of tau phosphorylation and amyloid metabolism during neuronal plasticity

BACKGROUND

Neural plasticity under physiological condition develops together with normal tau phosphorylation and amyloid precursor protein (APP) processing. Since restoration of PI3-kinase signaling has therapeutic potential in Alzheimer's disease, we investigated plasticity-related changes in tau and APP metabolism by the selective Rho-kinase inhibitor fasudil.

METHODS

Field potentials composed of a field excitatory post-synaptic potential (fEPSP) and a population spike (PS) were recorded from a granule cell layer of the dentate gyrus. Plasticity of synaptic strength and neuronal function was induced by strong tetanic stimulation (HFS) and low-frequency stimulation (LFS) patterns. Infusions of saline or fasudil were given for 1 h starting from the application of the induction protocols. Total and phosphorylated tau levels and soluble APPα levels were measured in the hippocampus, which was removed after at least 1 h post-induction period.

RESULTS

Fasudil infusion resulted in attenuation of fEPSP slope and PS amplitude in response to both HFS and LFS. Fasudil reduced total tau and phosphorylated tau at residue Thr¹⁸¹ in the HFS-stimulated hippocampus, while Thr²³¹ phosphorylation was reduced by fasudil treatment in the LFS-stimulated hippocampus. Ser⁴¹⁶ phosphorylation was increased by fasudil treatment in both HFS- and LFS-stimulated hippocampus. Fasudil significantly increased soluble APPα in LFS-stimulated hippocampus, but not in HFS-stimulated hippocampus.

CONCLUSION

In light of our findings, we suggest that increased activity of Rho kinase could trigger a mechanism that goes awry during synaptic plasticity which is reversed by a Rho-kinase inhibitor. Thus, Rho-kinase inhibition might be a therapeutic target in cognitive disorders.

Thrombin impairs the angiogenic activity of extravillous trophoblast cells via monocyte chemotactic protein-1 (MCP-1): A possible link with preeclampsia

Cytokines' secretion from the decidua and trophoblast cells has been known to regulate trophoblast cell functions, such as Extravillous trophoblasts (EVTs) cell migration and invasion and remodeling of spiral arteries. Defective angiogenesis and spiral arteries transformation are mainly caused by proinflammatory cytokines and excessive thrombin generation during preeclampsia. Monocyte chemotactic protein-1 (MCP-1), a crucial cytokine, has a role in maintaining normal pregnancy. In this study, we explored whether thrombin regulates the secretion of MCP-1 in HTR-8/SVneo cells; if yes, what is its function? We used HTR-8/SVneo cells, developed from first trimester villous explants of early pregnancy, as the model of EVTs. MCP-1 gene silencing was performed using gene-specific siRNA. qPCR and ELISA were performed to estimate the expression and secretion of MCP-1. Here, we found that thrombin enhanced the secretion of MCP-1 in HTR-8/SVneo cells. Proteinase-activated receptor-1 (PAR-1) was found as the primary receptor, regulating MCP-1 secretion in these cells. Furthermore, MCP-1 secretion is modulated via protein kinase C (PKC) α, β, and Rho/Rho-kinase-dependent pathways. Thrombin negatively regulates HTR-8/SVneo cells' ability to mimic tube formation in an MCP-1 dependent manner. In conclusion, we propose that thrombin-controlled MCP-1 secretion may play an essential role in normal placental development and successful pregnancy maintenance. Improper thrombin production and MCP-1 secretion during pregnancy might cause inadequate vascular formation and transformation of spiral arteries, which may contribute to pregnancy disorders, such as preeclampsia.

Oxidative stress, inflammation, and peritoneal dialysis: A molecular biology approach

The key role of oxidative stress (OxSt) and inflammation for the induction of cardiovascular disease, the leading cause of excess morbidity/mortality in chronic kidney disease and dialysis patients, is known and both the activations of NADPH oxidase and RhoA/Rho kinase (ROCK) pathway are pivotal for their effects. While specific hemodialysis procedures, such as hemodiafiltration with on‐line reinfusion of ultrafiltrate and/or the use of vitamin E‐coated dialyzers, are beneficial for OxSt and inflammation, studies in peritoneal dialysis (PD) are instead scarce and results seem not favorable. In nine patients under PD OxSt in terms of mononuclear cell protein level of p22^phox (Western blot), subunit of NADPH oxidase, essential for the generation of OxSt, and MYPT‐1 phosphorylation state (Western blot), a marker of ROCK activity, have been measured at the beginning and after 3 and 6 months of PD. Blood levels of interleukin 6 (IL‐6), ferritin, and albumin have been considered for evaluating the inflammatory state. p22^phox protein expression, MYPT‐1‐phosphorylation, and ferritin level were increased both at baseline vs healthy subjects (P = .02, P < .0001, P = .004, respectively) and vs baseline after 3 and 6 months of peritoneal dialysis (P = .007, P < .001, P = .004, respectively). Albumin was lower after 6 months of PD (P = .0014). IL‐6 was increased at baseline vs reference values and remained unchanged at 3 and 6 months. OxSt and inflammation increase during PD confirming via molecular biology approach a report at biochemical level. To improve OxSt state in PD, a multitarget approach is necessary. It might include the use of more physiologic pH, low glucose degradation products, low lactate and iso‐osmolar PD solutions, patients’ strict glycemic control, optimal volume management, and antioxidant administration, such as N‐acetylcysteine.

Tissue-specific regulation of epidermal contraction during C. elegans embryonic morphogenesis

Actin and myosin mediate the epidermal cell contractions that elongate the Caenorhabditis elegans embryo from an ovoid to a tubular-shaped worm. Contraction occurs mainly in the lateral epidermal cells, while the dorsoventral epidermis plays a more passive role. Two parallel pathways trigger actinomyosin contraction, one mediated by LET-502/Rho kinase and the other by PAK-1/p21 activated kinase. A number of genes mediating morphogenesis have been shown to be sufficient when expressed either laterally or dorsoventrally. Additional genes show either lateral or dorsoventral phenotypes. This led us to a model where contractile genes have discrete functions in one or the other cell type. We tested this by examining several genes for either lateral or dorsoventral sufficiency. LET-502 expression in the lateral cells was sufficient to drive elongation. MEL-11/Myosin phosphatase, which antagonizes contraction, and PAK-1 were expected to function dorsoventrally, but we could not detect tissue-specific sufficiency. Double mutants of lethal alleles predicted to decrease lateral contraction with those thought to increase dorsoventral force were previously shown to be viable. We hypothesized that these mutant combinations shifted the contractile force from the lateral to the dorsoventral cells and so the embryos would elongate with less lateral cell contraction. This was tested by examining 10 single and double mutant strains. In most cases, elongation proceeded without a noticeable alteration in lateral contraction. We suggest that many embryonic elongation genes likely act in both lateral and dorsoventral cells, even though they may have their primary focus in one or the other cell type.

Reverse Remodeling in Human Heart Failure after Cardiac Resynchronization Therapy Is Associated With Reduced RHO-Kinase Activation

Background: Reverse remodeling is a clinically relevant endpoint in heart failure with reduced ejection fraction (HFrEF). Rho-kinase (ROCK) signaling cascade activation correlates with cardiac remodeling and left ventricular (LV) systolic dysfunction in HFrEF patients. Cardiac resynchronization therapy (CRT) is effective in HFrEF, especially when there is a left bundle block, as this treatment may stimulate reverse remodeling, thereby improving quality of life and prolonging survival for patients with this severe condition. Here, we evaluate the hypothesis that ROCK activation is reduced after effective CRT in HFrEF. Methods: ROCK activation in circulating leukocytes was evaluated in 28 HFrHF patients, using Western blot (myosin light chain phosphatase subunit 1 phosphorylation, MYPT1p/t), before and three months after initiation of CRT. LV systolic function and remodeling were assessed by echocardiography. Results: Three months after CRT, LV ejection fraction increased an average of 14.5% (p < 0.001) in 13 patients (responders), while no change was observed in 15 patients (non-responders). End-systolic diameter decreased 16% (p < 0.001) in responders, with no change in non-responders. ROCK activation in PBMCs decreased 66% in responders (p < 0.05) but increased 10% in non-responders (NS). LV end-diastolic diameter was also 5.2 mm larger in non-responders vs. responders (p = 0.058). LV ejection fraction, systolic diameter, and ROCK activation levels were similar in both groups at baseline. Conclusion: In HFrEF patients, 3 months of effective CRT induced reverse myocardial remodeling, and ROCK activation was significantly decreased in circulating leukocytes. Thus, decreased ROCK activation in circulating leukocytes may reflect reverse cardiac remodeling in patients with heart failure.

Cooperation of augmented calcium sensitization and increased calcium entry contributes to high blood pressure in salt-sensitive Dahl rats

Salt hypertensive Dahl rats are characterized by sympathoexcitation and relative NO deficiency. We tested the hypothesis that the increased blood pressure (BP) response to fasudil in salt hypertensive Dahl rats is due to augmented calcium sensitization in the salt-sensitive strain and/or due to their decreased baroreflex efficiency. BP reduction after acute administration of nifedipine (an L-type voltage-dependent calcium channel blocker) or fasudil (a Rho kinase inhibitor) was studied in conscious intact rats and in rats subjected to acute NO synthase inhibition or combined blockade of the renin-angiotensin system (captopril), sympathetic nervous system (pentolinium), and NO synthase (L-NAME). Intact salt-sensitive (SS) Dahl rats fed a low-salt diet had greater BP responses to nifedipine (-31 ± 6 mmHg) or fasudil (-34 ± 7 mmHg) than salt-resistant (SR) Dahl rats (-16 ± 4 and -17 ± 2 mmHg, respectively), and a high-salt intake augmented the BP response only in SS rats. These BP responses were doubled after acute NO synthase inhibition, indicating that endogenous NO attenuates both calcium entry and calcium sensitization. Additional pentolinium administration, which minimized sympathetic compensation for the drug-induced BP reduction, magnified the BP responses to nifedipine or fasudil in all groups except for salt hypertensive SS rats due to their lower baroreflex efficiency. The BP response to the calcium channel blocker nifedipine can distinguish SS and SR rats even after calcium sensitization inhibition by fasudil, which was not seen when fasudil was administered to nifedipine-pretreated rats. Thus, enhanced calcium entry (potentiated by sympathoexcitation) in salt hypertensive Dahl rats is the abnormality that is essential for their BP increase, which was further augmented by increased calcium sensitization in salt-sensitive Dahl rats.

A novel ROCK inhibitor: off-target effects of metformin

In drug discovery, most small molecules cannot cross many stages, only a few can become drug candidates. Once the drug molecule is approved and marketed, nontarget effects that are not easily distinguishable from the actual target of the drugs might be evaluated. This situation restricts the treatment. Thus, the discovery of new drugs is a very long and expensive process. In recent years, without developing new drugs, the approach of using different and new target molecules in new indications apart from the indications of licensed drug molecules has gained importance.In this study, using the connectivity map program, it was determined that metformin and tolbutamide used in the treatment of type II diabetes had the potential to inhibit Rho kinase. In the experimental results to confirm this data, it has been shown that metformin and tolbutamide decrease the cell area within 24 h and metformin inhibits the activation of Rho kinase in MCF-7 cells.These results indicate that metformin, which is used in the treatment of type II diabetes, acts as a ROCK inhibitor. Metformin has potential in the treatment of various pathological conditions in which Rho kinase has a role.

Rectal administration of carbon monoxide inhibits the development of intestinal inflammation and promotes intestinal wound healing via the activation of the Rho-kinase pathway in rats

The inhalation of carbon monoxide (CO) gas and the administration of CO-releasing molecules were shown to inhibit the development of intestinal inflammation in a murine colitis model. However, it remains unclear whether CO promotes intestinal wound healing. Herein, we aimed to evaluate the therapeutic effects of the topical application of CO-saturated saline enemas on intestinal inflammation and elucidate the underlying mechanism. Acute colitis was induced with trinitrobenzene sulfonic acid (TNBS) in male Wistar rats. A CO-saturated solution was prepared via bubbling 50% CO gas into saline and was rectally administrated twice a day after colitis induction; rats were sacrificed 3 or 7 days after induction for the study of the acute or healing phases, respectively. The distal colon was isolated, and ulcerated lesions were measured. In vitro wound healing assays were also employed to determine the mechanism underlying rat intestinal epithelial cell restitution after CO treatment. CO solution rectal administration ameliorated acute TNBS-induced colonic ulceration and accelerated ulcer healing without elevating serum CO levels. The increase in thiobarbituric acid-reactive substances and myeloperoxidase activity after induction of acute TNBS colitis was also significantly inhibited after CO treatment. Moreover, the wound healing assays revealed that the CO-saturated medium enhanced rat intestinal epithelial cell migration via the activation of Rho-kinase. In addition, the activation of Rho-kinase in response to CO treatment was confirmed in the inflamed colonic tissue. Therefore, the rectal administration of a CO-saturated solution protects the intestinal mucosa from inflammation and accelerates colonic ulcer healing through enhanced epithelial cell restitution. CO may thus represent a novel therapeutic agent for the treatment of inflammatory bowel disease.

VIP modulates human macrophages phenotype via FPRL1 via activation of RhoA-GTPase and PLC pathways

OBJECTIVE AND DESIGN

This study is aimed at uncovering the signaling pathways activated by vasoactive intestinal peptide in human macrophages MATERIALS: Human peripheral blood mononuclear cell-derived macrophages were used for the in vitro investigation of the VIP-activated signaling pathways.

METHODS AND TREATMENT

Time-course and dose-response experiments and siRNA were used in human macrophages co-challenged with various concentrations of VIP and different MAPK pharmacologic inhibitors to investigate signaling pathways activated by VIP. Flow analysis was performed to assess the levels of CD11b, CD35 and CD66. Luminescence spectrometry was used to measure the levels of the released hydrogen peroxide and the intracellular calcium levels in the media.

RESULTS

Macrophages incubated with VIP showed increased phospho-AKT and phospho-ERK1/2 levels in a GTP-RhoA-GTPase-dependent manner. Similarly, VIP increased intracellular release of H₂O₂ and calcium via PLC and GTP-RhoA-GTPase, in addition to inducing the expression of CD11b, CD35, CD66 and MMP9. Furthermore, VIP activated P38 MAPK through the cAMP/PKA pathway but was independent of both PLC and RhoA signaling. The above-mentioned VIP effects were mediated via activation of the FPRL1 receptor.

CONCLUSION

VIP/FPRL1/VPAC/GTP-RhoA-GTPase signaling modulated macrophages phenotype through activation of multiple signaling pathways including ERK1/2, AKT, P38, ROS, cAMP and calcium.

Switching between blebbing and lamellipodia depends on the degree of non-muscle myosin II activity

Cells can adopt both mesenchymal and amoeboid modes of migration through membrane protrusive activities, namely formation of lamellipodia and blebbing. How the molecular players control the transition between lamellipodia and blebs is yet to be explored. Here, we show that addition of the ROCK inhibitor Y27632 or low doses of blebbistatin, an inhibitor of non-muscle myosin II (NMII) ATPase activity and filament partitioning, induces blebbing to lamellipodia conversion (BLC), whereas addition of low doses of ML7, an inhibitor of myosin light chain kinase (MLCK), induces lamellipodia to blebbing conversion (LBC) in human MDA-MB-231 cells. Similarly, siRNA-mediated knockdown of ROCK and MLCK induces BLC and LBC, respectively. Interestingly, both blebs and lamellipodia membrane protrusions are able to maintain the ratio of phosphorylated to unphosphorylated regulatory light chain at cortices when MLCK and ROCK, respectively, are inhibited either pharmacologically or genetically, suggesting that MLCK and ROCK activities are interlinked in BLC and LBC. Such BLCs and LBCs are also inducible in other cell lines, including MCF7 and MCF10A. These studies reveal that the relative activity of ROCK and MLCK, which controls both the ATPase activity and filament-forming property of NMII, is a determining factor in whether a cell exhibits blebbing or lamellipodia.

The Rho kinase 2 (ROCK2)-specific inhibitor KD025 ameliorates the development of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive and fatal disease that is characterized by the irreversible remodeling of the pulmonary artery. Although several PAH drugs have been developed, additional drugs are needed. Rho kinases (ROCKs) are involved in the pathogenesis of PAH, and thus, their inhibitors may prevent the development of PAH. However, the therapeutic benefits of ROCK isoform-specific inhibitors for PAH remain largely unknown. The in vitro and in vivo effects of the ROCK2-specific inhibitor, KD025, were examined herein using pulmonary arterial smooth muscle cells (PASMCs) from idiopathic pulmonary arterial hypertension (IPAH) patients and monocrotaline (MCT)-induced pulmonary hypertensive (PH) rats. The expression of ROCK1 was similar between normal- and IPAH-PASMCs, whereas that of ROCK2 was markedly higher in IPAH-PASMCs than in normal-PASMCs. KD025 inhibited the accelerated proliferation of IPAH-PASMCs in a concentration-dependent manner (IC50 = 289 nM). Accelerated proliferation was also reduced by the siRNA knockdown of ROCK2. In MCT-PH rats, the expression of ROCK2 was up-regulated in PASMCs. Elevated right ventricular systolic pressure in MCT-PH rats was attenuated by KD025 (1 mg/kg/day). These results strongly suggest that enhanced ROCK2 signaling is involved in the pathogenic mechanism underlying the development of PAH, including accelerated PASMC proliferation and vascular remodeling in patients with PAH. Therefore, ROCK2 may be a novel therapeutic target for the treatment of PAH.

AKAP12 Supports Blood-Brain Barrier Integrity against Ischemic Stroke

A-kinase anchor protein 12 (AKAP12) is a scaffolding protein that associates with intracellular molecules to regulate multiple signal transductions. Although the roles of AKAP12 in the central nervous system are still relatively understudied, it was previously shown that AKAP12 regulates blood-retinal barrier formation. In this study, we asked whether AKAP12 also supports the function and integrity of the blood-brain barrier (BBB). In a mouse model of focal ischemia, the expression level of AKAP12 in cerebral endothelial cells was upregulated during the acute phase of stroke. Also, in cultured cerebral endothelial cells, oxygen-glucose deprivation induced the upregulation of AKAP12. When AKAP12 expression was suppressed by an siRNA approach in cultured endothelial cells, endothelial permeability was increased along with the dysregulation of ZO-1/Claudin 5 expression. In addition, the loss of AKAP12 expression caused an upregulation/activation of the Rho kinase pathway, and treatment of Rho kinase inhibitor Y-27632 mitigated the increase of endothelial permeability in AKAP12-deficient endothelial cell cultures. These in vitro findings were confirmed by our in vivo experiments using Akap12 knockout mice. Compared to wild-type mice, Akap12 knockout mice showed a larger extent of BBB damage after stroke. However, the inhibition of rho kinase by Y-27632 tightened the BBB in Akap12 knockout mice. These data may suggest that endogenous AKAP12 works to alleviate the damage and dysfunction of the BBB caused by ischemic stress. Therefore, the AKAP12-rho-kinase signaling pathway represents a novel therapeutic target for stroke.

ROCK inhibition modulates the senescence-associated secretory phenotype (SASP) in oral keratinocytes

Senescent cells accumulate in different organs and develop a senescence‐associated secretory phenotype (SASP), associated with the development of age‐related pathologies. The constitution of the SASP varies among cell types and with the method of senescence induction; nevertheless, there is substantial overlap among SASPs, especially the presence of pro‐inflammatory cytokines such as IL‐1β, IL‐1α, IL‐6 and IL‐8. These cytokines are highly conserved among SASPs and are implicated in the development of several cancers. Here, we report that ROCK inhibition by Y‐27632 reduces levels of IL‐1α, IL‐1β, IL‐6 and IL‐8 secreted by senescent normal and dysplastic oral keratinocytes without affecting the permanent cell growth arrest. The data indicate some inflammatory genes downregulated by Y‐27632 remain downregulated even after repeated passage in the absence of Y‐27632. We propose ROCK kinase inhibition as a novel alternative to current strategies to modulate the inflammatory components of the SASP, without compromising the permanent cell growth arrest. This observation potentially has wide clinical applications, given the involvement of senescence in cancer and a wide range of age‐related disease. It also suggests care should be exercised when using Y‐27632 to facilitate cell expansion of primary cells, as its effects on gene expression are not entirely reversible.