Rho Kinases in Health and Disease: From Basic Science to Translational Research

Discovery of novel pyrazolo[1,5-a]pyrimidine derivatives as selective ROCK2 inhibitors with anti-breast cancer migration and invasion activities

Rho-associated coiled-coil kinase (ROCK) is involved in multiple cellular activities regulating the actin cytoskeleton, such as cell morphology, adhesion, and migration. The inhibition of ROCK is a feasible strategy to suppress breast cancer metastasis. Herein, based on Belumosudil, a series of pyrazolo[1,5-a]pyrimidine derivatives as selective ROCK2 inhibitors were designed and synthesized. Through systematic investigation of SARs, the piperazine analog 7u was identified with optimum ROCK2 inhibitory activity (IC50 = 36.8 nM) and excellent selectivity over the isoform protein ROCK1 (>250-fold). Intriguingly, upon treatment with 7u, the arrangement of the MDA-MB-231 cytoskeleton was affected accompanied by the alteration of morphology. Furthermore, cell scratch and transwell assays indicated that 7u inhibited MDA-MB-231 cell migration and invasion in a dose-dependent manner. Ultimately, the binding model of 7u with ROCK2 well accounted for the superior activities of 7u as a promising ROCK2 inhibitor with the potential application in breast cancer metastasis treatment.

Mechanism and application of feedback loops formed by mechanotransduction and histone modifications

Mechanical stimulation is the key physical factor in cell environment. Mechanotransduction acts as a fundamental regulator of cell behavior, regulating cell proliferation, differentiation, apoptosis, and exhibiting specific signature alterations during the pathological process. As research continues, the role of epigenetic science in mechanotransduction is attracting attention. However, the molecular mechanism of the synergistic effect between mechanotransduction and epigenetics in physiological and pathological processes has not been clarified. We focus on how histone modifications, as important components of epigenetics, are coordinated with multiple signaling pathways to control cell fate and disease progression. Specifically, we propose that histone modifications can form regulatory feedback loops with signaling pathways, that is, histone modifications can not only serve as downstream regulators of signaling pathways for target gene transcription but also provide feedback to regulate signaling pathways. Mechanotransduction and epigenetic changes could be potential markers and therapeutic targets in clinical practice.

Electroacupuncture improves retinal function in myopia Guinea pigs probably via inhibition of the RhoA/ROCK2 signaling pathway

Objective

To investigate the effect of electroacupuncture (EA) on retinal function in guinea pigs with negative lens-induced myopia (LIM) by inhibiting the RhoA/ROCK2 signaling pathway.

Methods

Guinea pigs were randomly divided into normal control (NC) group, LIM group, EA group, SHAM acupoint (SHAM) group, and electro-acupuncture + ROCK pathway inhibitor Y27632 (EA + Y27632) group. The refraction, axial length, retinal blood flow density, choroidal vascular index, retinal physiological function, the contents of total antioxidant capacity (T-AOC), catalase (CAT), glutathione (GSH), superoxide dismutase (SOD) and malondialdehyde (MDA) of each group were determined. The changes in retinal tissue structure were observed by hematoxylin and eosin (H&E) staining, and the expression of the RhoA/ROCK2 signaling pathway-related molecules in the retina was measured by real-time quantitative polymerase chain reaction (qPCR) and Western blot.

Results

Myopic refraction, AL, and MDA content in the LIM and SHAM groups were significantly increased, retinal blood flow density and CVI, SOD, GSH, CAT, T-AOC content were decreased. After EA intervention, myopic refraction, AL, and MDA content decreased, retinal blood flow density and CVI, SOD, GSH, CAT, T-AOC content were increased. H&E staining showed that the thickness of the guinea pig retina, the thickness of the inner and outer layers of the nucleus, and the number of cells were significantly increased after EA intervention. qPCR and western blot analyses showed that the expression of RhoA、ROCK2、MLC、CollagenⅠ、MMP-2、TIMP-2 and α-SMA were elevated in the LIM and SHAM group than those in the NC group. Compared with the LIM group, the expression of EA group was significantly decreased.

Conclusions

Electroacupuncture can improve retinal function by improving retinal blood flow, reducing retinal oxidative damage, inhibiting RhoA/ROCK2 signaling pathway and controlling extracellular matrix remodeling, thus delaying the occurrence and development of myopia.

Prenatal exposure to dibutyl phthalate contributes to erectile dysfunction in offspring male rats by activating the RhoA/ROCK signalling pathway

Prenatal exposure to dibutyl phthalate (DBP) has been reported to cause erectile dysfunction (ED) in adult offspring rats. However, its underlying mechanisms are not fully understood. Previously, we found that DBP activates the RhoA/ROCK pathway in the male reproductive system. This study investigated how prenatal exposure to DBP activates the RhoA/ROCK signalling pathway, leading to ED in male rat offspring. Pregnant rats were stratified into DBP-exposed and NC groups, with the exposed group receiving 750 milligrams per kilogram per day (mg/kg/day) of DBP through gavage from days 14-18 of gestation. DBP exposure activated the RhoA/ROCK pathway in the penile corpus cavernosum (CC) of descendants, causing smooth muscle cell contraction, fibrosis, and apoptosis, all of which contribute to ED. In vitro experiments confirmed that DBP induces apoptosis and RhoA/ROCK pathway activation in CC smooth muscle cells. Treatment of DBP-exposed offspring with the ROCK inhibitor Y-27632 for 8 weeks significantly improved smooth muscle cell condition, erectile function, and reduced fibrosis. Thus, prenatal DBP exposure induces ED in offspring through RhoA/ROCK pathway activation, and the ROCK inhibitor Y-27632 shows potential as an effective treatment for DBP-induced ED.

The ROCK inhibitor netarsudil in the treatment of corneal endothelial decompensation caused by corneal endotheliitis: A case report and literature review

Proper hydration and the clarity of the cornea are maintained through the crucial function of the corneal endothelium. Inflammation of the corneal endothelium, known as endotheliitis, can disrupt endothelial function, resulting in alterations to vision. Corneal endotheliitis is characterised by corneal oedema, the presence of keratic precipitates, inflammation within the anterior chamber, and occasionally, limbal injection, neovascularisation, and the concurrent or overlapping presence of uveitis. The aetiology of this condition is diverse, predominantly viral, but it may also be drug-induced, result from bacterial or fungal infections, be associated with systemic diseases and procedures, or remain idiopathic with no identifiable cause. To date, no standardised protocol for the treatment of this ocular disease exists, and in severe cases, corneal transplantation may be required. A 31-year-old male was transferred to our hospital for the management of corneal endothelial decompensation resulting from corneal endotheliitis. Hormonal therapy and antiviral medications proved ineffective, rendering the patient a candidate for corneal transplantation. As a final measure, treatment with the ROCK inhibitor netarsudil was initiated. The patient demonstrated significant improvement in symptoms, and the inflammation was successfully managed after nine months. In this study, a novel approach employing ROCK inhibitor therapy was utilised for the treatment of corneal endotheliitis, leading to marked recovery during patient follow-up. This case report represents the inaugural application of the ROCK inhibitor netarsudil in managing corneal endothelial decompensation attributed to corneal endotheliitis. These findings suggest that this method warrants consideration as a potential novel treatment option for similar conditions.

DDR1 Drives Malignant Progression of Gastric Cancer by Suppressing HIF-1α Ubiquitination and Degradation

The extracellular matrix (ECM) has been demonstrated to be dysregulated and crucial for malignant progression in gastric cancer (GC), but the mechanism is not well understood. Here, that discoidin domain receptor 1 (DDR1), a principal ECM receptor, is recognized as a key driver of GC progression is reported. Mechanistically, DDR1 directly interacts with the PAS domain of hypoxia-inducible factor-1α (HIF-1α), suppresses its ubiquitination and subsequently strengthens its transcriptional regulation of angiogenesis. Additionally, DDR1 upregulation in GC cells promotes actin cytoskeleton reorganization by activating HIF-1α/ Ras Homolog Family Member A (RhoA)/Rho-associated protein kinase 1 (ROCK1) signaling, which in turn enhances the metastatic capacity. Pharmacological inhibition of DDR1 suppresses GC progression and angiogenesis in patient-derived xenograft (PDX) and organoid models. Taken together, this work first indicates the effects of the DDR1-HIF-1α axis on GC progression and reveals the related mechanisms, providing experimental evidence for DDR1 as a therapeutic target for GC.

Caught between a ROCK and a hard place: current challenges in structure-based drug design

The discipline of structure-based drug design (SBDD) is several decades old and it is tempting to think that the proliferation of experimental structures for many drug targets might make computer-aided drug design (CADD) straightforward. However, this is far from true. In this review, we illustrate some of the challenges that CADD scientists face every day in their work, even now. We use Rho-associated protein kinase (ROCK), and public domain structures and data, as an example to illustrate some of the challenges we have experienced during our project targeting this protein. We hope that this will help to prevent unrealistic expectations of what CADD can accomplish and to educate non-CADD scientists regarding the challenges still facing their CADD colleagues.

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.

The Application of Rho Kinase Inhibitors in the Management of Glaucoma

Glaucoma is a chronic neurodegenerative disease that poses a significant threat of irreversible blindness worldwide. Current treatments for glaucoma focus on reducing intraocular pressure (IOP), which is the only modifiable risk factor. Traditional anti-glaucomatous agents, including carbonic anhydrase inhibitors, beta-blockers, alpha-2 agonists, and prostaglandin analogs, work by either improving uveoscleral outflow or reducing aqueous humor production. Rho kinase (ROCK) inhibitors represent a novel class of anti-glaucomatous drugs that have emerged from bench to bedside in the past decade, offering multifunctional characteristics. Unlike conventional medications, ROCK inhibitors directly target the trabecular meshwork outflow pathway. This review aims to discuss the mechanism of ROCK inhibitors in reducing IOP, providing neuroprotection, and preventing fibrosis. We also highlight recent studies and clinical trials evaluating the efficacy and safety of ROCK inhibitors, compare them with other clinical anti-glaucomatous medications, and outline future prospects for ROCK inhibitors in glaucoma treatment.

Advancements in neuroregenerative and neuroprotective therapies for traumatic spinal cord injury

Traumatic spinal cord injuries (SCIs) continue to be a major healthcare concern, with a rising prevalence worldwide. In response to this growing medical challenge, considerable scientific attention has been devoted to developing neuroprotective and neuroregenerative strategies aimed at improving the prognosis and quality of life for individuals with SCIs. This comprehensive review aims to provide an up-to-date and thorough overview of the latest neuroregenerative and neuroprotective therapies currently under investigation. These strategies encompass a multifaceted approach that include neuropharmacological interventions, cell-based therapies, and other promising strategies such as biomaterial scaffolds and neuro-modulation therapies. In addition, the review discusses the importance of acute clinical management, including the role of hemodynamic management as well as timing and technical aspects of surgery as key factors mitigating the secondary injury following SCI. In conclusion, this review underscores the ongoing scientific efforts to enhance patient outcomes and quality of life, focusing on upcoming strategies for the management of traumatic SCI. Each section provides a working knowledge of the fundamental preclinical and patient trials relevant to clinicians while underscoring the pathophysiologic rationale for the therapies.

Antibiotic bone cement accelerates diabetic foot wound healing: Elucidating the role of ROCK1 protein expression

Clinical studies indicate antibiotic bone cement with propeller flaps improves diabetic foot wound repair and reduces amputation rates, but the molecular mechanisms, particularly key proteins' role remain largely unexplored. This study assessed the efficacy of antibiotic bone cement for treating diabetic foot wounds, focusing on molecular impact on ROCK1. Sixty patients were randomized into experimental (EXP, n = 40) and control (CON, n = 20) groups, treated with antibiotic bone cement and negative pressure. Wound healing rate, amputation rate, wound secretion culture and C-reactive protein (CRP) changes, were monitored. Comprehensive molecular investigations were conducted and animal experiments were performed to further validate the findings. Statistical methods were employed to verify significant differences between the groups and treatment outcomes. The EXP group showed significant improvements in wound healing (χ 2 $$ {\chi}^2 $$ = 11.265, p = 0.004) and reduced amputation rates. Elevated levels of ROCK1, fibroblasts and VGF were observed in the trauma tissue post-treatment in the experimental group compared to pre-treatment and the control group (all p < 0.05). Improved trauma secretion culture and CRP were also noted in the EXP group (all p < 0.05). The study suggests that antibiotic bone cement enhances diabetic foot wound healing, possibly via upregulation of ROCK1. Further research is needed to elucidate the underlying molecular mechanisms and broader clinical implications.

The Effect of Rho Kinase Inhibitors on In Vitro Human Orbital Preadipocytes

PURPOSE

To identify the effects of Rho Kinase (ROCK) inhibitor medications on human orbital adipogenesis, fibroblast proliferation, and fibrosis.

METHODS

Orbital adipose tissue was obtained from patients with Graves' ophthalmopathy (GO) as well as controls (non-GO or normal) after informed consent was done. These tissue samples were cultured and adipogenesis was initiated. Levels of Rho Kinase as well as cellular mediators of orbital inflammation and fibrosis. The same cultures and measurements were then repeated with the use of a ROCK inhibitor (KD025-ROCK2) to assess for changes in adipogenesis as well as markers associated with inflammation and fibrosis.

RESULTS

Rho Kinase levels in GO tissue were more highly expressed than in controls. These levels were suppressed with the use of the ROCK inhibitor KD025. There was a dose-dependent reduction in differentiation of orbital adipocytes with the use of KD025. KD025 reduced the levels of fibrosis-related gene expression. Finally, there was a significant reduction of transforming growth factor beta mediated phosphorylation signaling pathways in the KD025-treated GO tissue.

CONCLUSION

This study shows that the ROCK inhibitor, KD025, helps to reduce the expression of ROCK in GO tissue along with reducing orbital adipocyte differentiation as well as cell mediators involved in fibrosis that occurs in GO.

CircFN1 promotes acute myeloid leukemia cell proliferation and invasion but refrains apoptosis via miR-1294/ARHGEF10L axis

Previous studies have proved circFN1 is highly expressed in acute myeloid leukemia (AML) patients and AML cell lines. This study aims to investigate the impact of circFN1 on AML and its mechanism. Via real-time quantitative PCR to detect circFN1, miR-1294, ARHGEF10L expressions in clinical plasma samples and AML cell lines, AML cells were cultured in vitro and transfected with si-circFN1, pcDNA3.1-circFN1, and si-ARHGEF10L, respectively, or co-transfected pcDNA3.1-circFN1 + miR-1294 mimic and pcDNA3.1-circFN1 + si-ARHGEF10L. Using dual luciferase reporter experiment to detect the relationship between circFN1 and miR-1294, as well as miR-1294 and ARHGEF10L. CCK-8 was used to detect cell proliferation, Transwell to cell invasion, TUNEL staining and flow cytometry to detect cell apoptosis, RT-qPCR to circFN1 RNA, miR-1294, and ARHGEF10L expression levels in HL-60 cells, and western blot to ARHGEF10L protein expression level in HL-60 cells. We found highly expressed circFN1 and ARHGEF10L, as well as low-expressed miR-1294 in AML patients and AML cell lines. In contrast to si-NC group, si-circFN1 group could signally inhibit HL-60 cell proliferation and migration, but promote cell apoptosis; compared with mimic NC group, miR-1294 mimic group could visually inhibit HL-60 cell proliferation and migration, but promote cell apoptosis. miR-1294 was the target of circFN1, and ARHGEF10L was the target of miR-1294. Over-expressing miR-1294 or silencing ARHGEF10L could signally inhibit circFN1 promoting HL-60 cell proliferation and migration and repressing cell apoptosis. circFN1 promotes proliferation and invasion of AML cell and represses cell apoptosis via regulating miR-1294/ARHGEF10L axis, which provides new insight for molecular targeted-treatment for AML.

YAP1 Recognizes Inflammatory and Mechanical Cues to Exacerbate Benign Prostatic Hyperplasia via Promoting Cell Survival and Fibrosis

Chronic prostatic inflammation promotes cell survival and fibrosis, leading to benign prostatic hyperplasia (BPH) with aggravated urinary symptoms. It is investigated whether yes-associated protein 1 (YAP1), an organ size controller and mechanical transductor, is implicated in inflammation-induced BPH. The correlation between YAP1 expression and fibrosis in human and rat BPH specimens is analyzed. Furthermore, the effects of YAP1 activation on prostatic cell survival and fibrosis, as well as the underlying mechanism, are also studied. As a result, total and nuclear YAP1 expression, along with downstream genes are significantly upregulated in inflammation-associated human and rat specimens. There is a significant positive correlation between YAP1 expression and the severity of fibrosis or clinical performance. YAP1 silencing suppresses cell survival by decreasing cell proliferation and increasing apoptosis, and alleviates fibrosis by reversing epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM) deposition in prostatic BPH-1 and WPMY-1 cells. Mechanistically, inflammatory stimulus and rigid matrix stiffness synergistically activate the RhoA/ROCK1 pathway to provoke cytoskeleton remodeling, thereby promoting YAP1 activation to exacerbate BPH development. Overall, inflammation-triggered mechanical stiffness reinforcement activates the RhoA/ROCK1/F-actin/YAP1 axis, thereby promoting prostatic cell survival and fibrosis to accelerate BPH progression.

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.

Promising Cerebral Blood Flow Enhancers in Acute Ischemic Stroke

Ischemic stroke presents a major global economic and public health burden. Although recent advances in available endovascular therapies show improved functional outcome, a good number of stroke patients are either ineligible or do not have access to these treatments. Also, robust collateral flow during acute ischemic stroke independently predicts the success of endovascular therapies and the outcome of stroke. Hence, adjunctive therapies for cerebral blood flow (CBF) enhancement are urgently needed. A very clear overview of the pial collaterals and the role of genetics are presented in this review. We review available evidence and advancement for potential therapies aimed at improving CBF during acute ischemic stroke. We identified heme-free soluble guanylate cyclase activators; Sanguinate, remote ischemic perconditioning; Fasudil, S1P agonists; and stimulation of the sphenopalatine ganglion as promising potential CBF-enhancing therapeutics requiring further investigation. Additionally, we outline and discuss the critical steps required to advance research strategies for clinically translatable CBF-enhancing agents in the context of acute ischemic stroke models.

LKB1 loss promotes colorectal cancer cell metastasis through regulating TNIK expression and actin cytoskeleton remodeling

Colorectal cancer (CRC) is one of the most common malignant tumors. Approximately 5%-6% of CRC cases are associated with hereditary CRC syndromes, including the Peutz-Jeghers syndrome (PJS). Liver kinase B1 (LKB1), also known as STK11, is the major gene responsible for PJS. LKB1 heterozygotic deficiency is involved in intestinal polyps in mice, while the mechanism of LKB1 in CRC remains elusive. In this study, we generated LKB1 knockout (KO) CRC cell lines by using CRISPR-Cas9. LKB1 KO promoted CRC cell motility in vitro and tumor metastases in vivo. LKB1 attenuated expression of TRAF2 and NCK-interacting protein kinase (TNIK) as accessed by RNA-seq and western blots, and similar suppression was also detected in the tumor tissues of azoxymethane/dextran sodium sulfate-induced intestinal-specific LKB1-KO mice. LKB1 repressed TNIK expression through its kinase activity. Moreover, attenuating TNIK by shRNA inhibited cell migration and invasion of CRC cells. LKB1 loss-induced high metastatic potential of CRC cells was depended on TNIK upregulation. Furthermore, TNIK interacted with ARHGAP29 and further affected actin cytoskeleton remodeling. Taken together, LKB1 deficiency promoted CRC cell metastasis via TNIK upregulation and subsequently mediated cytoskeleton remodeling. These results suggest that LKB1-TNIK axis may play a crucial role in CRC progression.

A multi-laboratory preclinical trial in rodents to assess treatment candidates for acute ischemic stroke

Human diseases may be modeled in animals to allow preclinical assessment of putative new clinical interventions. Recent, highly publicized failures of large clinical trials called into question the rigor, design, and value of preclinical assessment. We established the Stroke Preclinical Assessment Network (SPAN) to design and implement a randomized, controlled, blinded, multi-laboratory trial for the rigorous assessment of candidate stroke treatments combined with intravascular thrombectomy. Efficacy and futility boundaries in a multi-arm multi-stage statistical design aimed to exclude from further study highly effective or futile interventions after each of four sequential stages. Six independent research laboratories performed a standard focal cerebral ischemic insult in five animal models that included equal numbers of males and females: young mice, young rats, aging mice, mice with diet-induced obesity, and spontaneously hypertensive rats. The laboratories adhered to a common protocol and efficiently enrolled 2615 animals with full data completion and comprehensive animal tracking. SPAN successfully implemented treatment masking, randomization, prerandomization inclusion and exclusion criteria, and blinded assessment of outcomes. The SPAN design and infrastructure provide an effective approach that could be used in similar preclinical, multi-laboratory studies in other disease areas and should help improve reproducibility in translational science.

Identification of ROCK1 as a novel biomarker for postmenopausal osteoporosis and pan-cancer analysis

BACKGROUND

Postmenopausal osteoporosis (PMOP) is a prevalent bone disorder with significant global impact. The elevated risk of osteoporotic fracture in elderly women poses a substantial burden on individuals and society. Unfortunately, the current lack of dependable diagnostic markers and precise therapeutic targets for PMOP remains a major challenge.

METHODS

PMOP-related datasets GSE7429, GSE56814, GSE56815, and GSE147287, were downloaded from the GEO database. The DEGs were identified by "limma" packages. WGCNA and Machine Learning were used to choose key module genes highly related to PMOP. GSEA, DO, GO, and KEGG enrichment analysis was performed on all DEGs and the selected key hub genes. The PPI network was constructed through the GeneMANIA database. ROC curves and AUC values validated the diagnostic values of the hub genes in both training and validation datasets. xCell immune infiltration and single-cell analysis identified the hub genes' function on immune reaction in PMOP. Pan-cancer analysis revealed the role of the hub genes in cancers.

RESULTS

A total of 1278 DEGs were identified between PMOP patients and the healthy controls. The purple module and cyan module were selected as the key modules and 112 common genes were selected after combining the DEGs and module genes. Five Machine Learning algorithms screened three hub genes (KCNJ2, HIPK1, and ROCK1), and a PPI network was constructed for the hub genes. ROC curves validate the diagnostic values of ROCK1 in both the training (AUC = 0.73) and validation datasets of PMOP (AUC = 0.81). GSEA was performed for the low-ROCK1 patients, and the top enriched field included protein binding and immune reaction. DCs and NKT cells were highly expressed in PMOP. Pan-cancer analysis showed a correlation between low ROCK1 expression and SKCM as well as renal tumors (KIRP, KICH, and KIRC).

CONCLUSIONS

ROCK1 was significantly associated with the pathogenesis and immune infiltration of PMOP, and influenced cancer development, progression, and prognosis, which provided a potential therapy target for PMOP and tumors. However, further laboratory and clinical evidence is required before the clinical application of ROCK1 as a therapeutic target.

Chylomicrons Regulate Lacteal Permeability and Intestinal Lipid Absorption

BACKGROUND

Lymphatic vessels are responsible for tissue drainage, and their malfunction is associated with chronic diseases. Lymph uptake occurs via specialized open cell-cell junctions between capillary lymphatic endothelial cells (LECs), whereas closed junctions in collecting LECs prevent lymph leakage. LEC junctions are known to dynamically remodel in development and disease, but how lymphatic permeability is regulated remains poorly understood.

METHODS

We used various genetically engineered mouse models in combination with cellular, biochemical, and molecular biology approaches to elucidate the signaling pathways regulating junction morphology and function in lymphatic capillaries.

RESULTS

By studying the permeability of intestinal lacteal capillaries to lipoprotein particles known as chylomicrons, we show that ROCK (Rho-associated kinase)-dependent cytoskeletal contractility is a fundamental mechanism of LEC permeability regulation. We show that chylomicron-derived lipids trigger neonatal lacteal junction opening via ROCK-dependent contraction of junction-anchored stress fibers. LEC-specific ROCK deletion abolished junction opening and plasma lipid uptake. Chylomicrons additionally inhibited VEGF (vascular endothelial growth factor)-A signaling. We show that VEGF-A antagonizes LEC junction opening via VEGFR (VEGF receptor) 2 and VEGFR3-dependent PI3K (phosphatidylinositol 3-kinase)/AKT (protein kinase B) activation of the small GTPase RAC1 (Rac family small GTPase 1), thereby restricting RhoA (Ras homolog family member A)/ROCK-mediated cytoskeleton contraction.

CONCLUSIONS

Our results reveal that antagonistic inputs into ROCK-dependent cytoskeleton contractions regulate the interconversion of lymphatic junctions in the intestine and in other tissues, providing a tunable mechanism to control the lymphatic barrier.

Beta-Secretase 1 Recruits Amyloid-Beta Precursor Protein to ROCK2 Kinase, Resulting in Erroneous Phosphorylation and Beta-Amyloid Plaque Formation

The amyloidogenic processing of APP depends on two events: its phosphorylation by ROCK2 (at Thr654) and the phosphorylation of the APP-cleaving enzyme BACE1 (at Ser498). However, the mechanisms and structural details of APP-ROCK2 and BACE1-ROCK2 binding are unknown. Using direct physical methods in combination with an in silico approach, we found that BACE1 binds into the substrate-binding groove of ROCK2 with a low affinity (K_d = 18 µM), while no binding of APP to ROCK2 alone could be detected. On the other hand, a strong association (K_d = 3.5 nM) of APP to the weak ROCK2-BACE1 complex was observed, although no stable ternary complex was detected, i.e., BACE1 was displaced by APP. We constructed a sequential functional model: (1) BACE1 weakly binds to ROCK2 and induces an allosteric conformational change in ROCK2; (2) APP strongly binds to the ROCK2-BACE1 complex, and BACE1 is released; and (3) ROCK2 phosphorylates APP at Thr654 (leading to a longer stay in the early endosome during APP processing). Direct fluorescence titration experiments showed that the APP_646-664 or APP_665-695 fragments did not bind separately to the ROCK2-BACE1 complex. Based on these observations, we conclude that two binding sites are involved in the ROCK2-APP interaction: (1) the substrate-binding groove, where the APP_646-664 sequence containing Thr654 sits and (2) the allosteric binding site, where the APP_665-695 sequence binds. These results open the way to attack the allosteric site to prevent APP phosphorylation at Thr654 by ROCK2 without inhibiting the activity of ROCK2 towards its other substrates.

Research advances in endometriosis-related signaling pathways: A review

Endometriosis (EM) is characterized by the existence of endometrial mucosa outside the uterine cavity, which causesinfertility, persistent aches, and a decline in women's quality of life. Both hormone therapies and nonhormone therapies, such as NSAIDs, are ineffective, generic categories of EM drugs. Endometriosis is a benign gynecological condition, yet it shares a number of features with cancer cells, including immune evasion, survival, adhesion, invasion, and angiogenesis. Several endometriosis-related signaling pathways are comprehensively reviewed in this article, including E2, NF-κB, MAPK, ERK, PI3K/Akt/mTOR, YAP, Wnt/β-catenin, Rho/ROCK, TGF-β, VEGF, NO, iron, cytokines and chemokines. To find and develop novel medications for the treatment of EM, it is essential to implicitly determine the molecular pathways that are disordered during EM development. Additionally, research on the shared pathways between EM and tumors can provide hypotheses or suggestions for endometriosis therapeutic targets.

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.

Exosomal miR‑152‑5p/ARHGAP6/ROCK axis regulates apoptosis and fibrosis in cardiomyocytes

Acute myocardial infarction (AMI) is a fatal cardiovascular disease with a high mortality rate. The discovery of effective biomarkers is crucial for the diagnosis and treatment of AMI. In the present study, miRNA sequencing and reverse transcription-quantitative polymerase chain reaction techniques revealed that the expression of exosome derived miR-152-5p was significantly downregulated in patients with AMI compared with healthy controls. A series of functional validation experiments were then performed using H9c2 cardiomyocytes. Following transfection of the cardiomyocytes using an miR-152-5p inhibitor, immunofluorescence staining of a-smooth muscle actin revealed a marked increase in fibrosis. Western blotting revealed that the expression levels of the apoptotic protein Bax, TNF-α and collagen-associated proteins were significantly increased, whereas those of the apoptosis-inhibiting factor Bcl-2 and vascular endothelial growth factor A were significantly decreased. Furthermore, the binding of Rho GTPase-activating protein 6 (ARHGAP6) to miR-152-5p was predicted using an online database and verified using a dual-luciferase reporter gene assay. The transfection of cardiomyocytes with miR-152-5p mimics was found to inhibit the activation of ARHGAP6 and Rho-associated coiled-coil containing kinase 2 (ROCK2). These results suggest that miR-152-5p targets ARHGAP6 through the ROCK signaling pathway to inhibit AMI, which implies that miR-152-5p may be a diagnostic indicator and potential target for treatment of myocardial infarction.

Cell migration induces apoptosis in osteosarcoma cell via inhibition of Wnt-β-catenin signaling pathway

The current design scheme on anti-cancer materials is mainly through tuning the mechanical properties of the materials to induce apoptosis in cancer cells, with the involvement of Rho/ROCK signaling pathway. We hypothesize that tuning the motility is another potential important approach to modifying the tumor microenvironment and inducing tumor apoptosis. To this aim, we have prepared RGD-modified substrates to regulate cell motility through modification of RGD with different concentrations, and systematically examined the effect of motility on the apoptosis of tumor cells, and the potential involvement of Wnt signaling pathway. Our studies indicated that RGD modification could be readily used to tune the motility of cancer cells. High RGD concentration significantly suppressed the migration of cancer cells, leading to significantly increased apoptosis rate, about three times of that of the unmodified samples. Western-blot analysis also showed that cell with low motility expressed more caspase-3 and PARP proteins. Further RNA sequence study strongly suggested that low motility inhibited the canonical Wnt signaling pathway, which in turn led to the activation of the mitochondria-associated caspase signaling pathway, and ultimately to the apoptosis of osteosarcoma cells. Activation of the Wnt-β-catenin pathway through HLY78 significantly suppressed the apoptosis of MG-63 cells, further suggesting the critical role of Wnt pathway in motility-regulated-apoptosis of tumor cells. Our findings shed insights to understand the underlying mechanisms that induced the tumor cell apoptosis, and might provide new strategy for designing the novel anti-tumor materials.

Roles of the cytoskeleton in human diseases

Recently, researches have revealed the key roles of the cytoskeleton in the occurrence and development of multiple diseases, suggesting that targeting the cytoskeleton is a viable approach for treating numerous refractory diseases. The cytoskeleton is a highly structured and complex network composed of actin filaments, microtubules, and intermediate filaments. In normal cells, these three cytoskeleton components are highly integrated and coordinated. However, the cytoskeleton undergoes drastic remodeling in cytoskeleton-related diseases, causing changes in cell polarity, affecting the cell cycle, leading to senescent diseases, and influencing cell migration to accelerate cancer metastasis. Additionally, mutations or abnormalities in cytoskeletal proteins and their related proteins are closely associated with several congenital diseases. Therefore, this review summarizes the roles of the cytoskeleton in cytoskeleton-related diseases as well as its potential roles in disease treatment to provide insights regarding the physiological functions and pathological roles of the cytoskeleton.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

The Role of Myofibroblasts in Physiological and Pathological Tissue Repair

Myofibroblasts are the construction workers of wound healing and repair damaged tissues by producing and organizing collagen/extracellular matrix (ECM) into scar tissue. Scar tissue effectively and quickly restores the mechanical integrity of lost tissue architecture but comes at the price of lost tissue functionality. Fibrotic diseases caused by excessive or persistent myofibroblast activity can lead to organ failure. This review defines myofibroblast terminology, phenotypic characteristics, and functions. We will focus on the central role of the cell, ECM, and tissue mechanics in regulating tissue repair by controlling myofibroblast action. Additionally, we will discuss how therapies based on mechanical intervention potentially ameliorate wound healing outcomes. Although myofibroblast physiology and pathology affect all organs, we will emphasize cutaneous wound healing and hypertrophic scarring as paradigms for normal tissue repair versus fibrosis. A central message of this review is that myofibroblasts can be activated from multiple cell sources, varying with local environment and type of injury, to either restore tissue integrity and organ function or create an inappropriate mechanical environment.

A systematic review on the effects of ROCK inhibitors on proliferation and/or differentiation in human somatic stem cells: A hypothesis that ROCK inhibitors support corneal endothelial healing via acting on the limbal stem cell niche

Rho kinase inhibitors (ROCKi) have attracted growing multidisciplinary interest, particularly in Ophthalmology where the question as to how they promote corneal endothelial healing remains unresolved. Concurrently, stem cell biology has rapidly progressed in unravelling drivers of stem cell (SC) proliferation and differentiation, where mechanical niche factors and the actin cytoskeleton are increasingly recognized as key players. There is mounting evidence from the study of the peripheral corneal endothelium that supports the likelihood of an internal limbal stem cell niche. The possibility that ROCKi stimulate the endothelial SC niche has not been addressed. Furthermore, there is currently a paucity of data that directly evaluates whether ROCKi promotes corneal endothelial healing by acting on this limbal SC niche located near the transition zone. Therefore, we performed a systematic review examining the effects ROCKi on the proliferation and differentiation of human somatic SC, to provide insight into its effects on various human SC populations. An appraisal of electronic searches of four databases identified 1 in vivo and 58 in vitro studies (36 evaluated proliferation while 53 examined differentiation). Types of SC studied included mesenchymal (n = 32), epithelial (n = 11), epidermal (n = 8), hematopoietic and other (n = 8). The ROCK 1/2 selective inhibitor Y-27632 was used in almost all studies (n = 58), while several studies evaluated ≥2 ROCKi (n = 4) including fasudil, H-1152, and KD025. ROCKi significantly influenced human somatic SC proliferation in 81% of studies (29/36) and SC differentiation in 94% of studies (50/53). The present systemic review highlights that ROCKi are influential in regulating human SC proliferation and differentiation, and provides evidence to support the hypothesis that ROCKi promotes corneal endothelial division and maintenance via acting on the inner limbal SC niche.

Rho-kinase Inhibitors in Ocular Diseases: A Translational Research Journey

Aim

This review summarizes current data on Rho-kinase (ROCK) inhibitors use in ocular diseases, primarily glaucoma.

Background

Translational research over the last decade culminating in the development of ROCK inhibitors has provided a much-needed shot in the arm to glaucoma pharmacopeia. ROCK pathway is intricately involved in cytoskeletal modulation with action on cell morphology, cell motility, cell adhesion, cell apoptosis, and smooth muscle contraction. This cytoskeletal modulation property has been utilized to modify trabecular meshwork (TM) resistance, resulting in the discovery of ROCK inhibitors to increase trabecular outflow.

Review results

Multicentric trials on ROCK inhibitors for antiglaucoma medications are summarized. The focus is on linking pharmacological action to the clinical utility of these drugs. While the Rho Kinase Elevated intraocular Pressure (IOP) Treatment (ROCKET) trials compared monotherapy with ROCK inhibitor netarsudil vs timolol, MERCURY trials compared a fixed dose combination of latanoprost and ROCK inhibitor netarsudil [fixed combination netarsudil-latanoprost (FCNL)] vs monotherapy with either and bimatoprost-timolol combination. While ROCKET trials showed ROCK inhibitors to be non-inferior to timolol, MERCURY trials showed FCNL achieving a much greater IOP reduction than monotherapy with either. Conjunctival hyperemia was the most common side effect reported with ROCK inhibitor use.

Conclusion

Moderate efficacy of ROCK inhibitors with a common side effect of conjunctival hyperemia, makes it an adjunctive antiglaucoma drug of choice and not a first-line therapy.

Clinical significance

ROCK inhibitors' action on diseased TM is more physiological compared to available antiglaucoma medications that either reduce aqueous secretion or enhance uveoscleral outflow. The property of ROCK inhibition to stabilize the endothelium of both retinal vasculature and cornea has opened a new chapter in the treatment of diabetic retinopathy and corneal decompensation.

How to cite this article

Singh K, Singh A. Rho-kinase Inhibitors in Ocular Diseases: A Translational Research Journey. J Curr Glaucoma Pract 2023;17(1):44-48.

CCL2 promotes proliferation, migration and angiogenesis through the MAPK/ERK1/2/MMP9, PI3K/AKT, Wnt/β‑catenin signaling pathways in HUVECs

Severe bone trauma can lead to poor or delayed bone healing and nonunion. Bone regeneration is based on the interaction between osteogenesis and angiogenesis. Angiogenesis serves a unique role in the repair and remodeling of bone defects. Monocyte chemoattractant protein-1, also known as CC motif ligand 2 (CCL2), is a member of the CC motif chemokine family and was the first human chemokine to be revealed to be an effective chemokine of monocytes. However, its underlying mechanism in angiogenesis of bone defect repair remains to be elucidated. Therefore, the present study investigated the detailed mechanism by which CCL2 promoted angiogenesis in bone defects based on cell and animal model experiments. In the present study, CCL2 promoted proliferation, migration and tube formation in human umbilical vein endothelial cells (HUVECs) in a concentration-dependent manner. Western blot analysis revealed that treatment of HUVECs with CCL2 upregulated the protein expression levels of rho-associated coiled-coil-containing protein kinase (Rock)1, Rock2, N-cadherin, c-Myc and VEGFR2. Furthermore, CCL2 promoted the expression of MAPK/ERK1/2/MMP9, PI3K/AKT and Wnt/β-catenin signaling pathway-related proteins, which also demonstrated that CCL2 promoted these functions in HUVECs. Immunohistochemical staining of Sprague Dawley rat femurs following bone defects revealed that VEGF expression was positive in the newly formed bone area in each group, while the expression area of VEGF in the CCL2 addition group was markedly increased. Therefore, CCL2 is a potential therapeutic approach for bone defect repair and reconstruction through the mechanism of angiogenesis-osteogenesis coupling.

The anti-asthmatic potential of Rho-kinase inhibitor hydroxyfasudil in the model of experimentally induced allergic airway inflammation

OBJECTIVE

This experimental study evaluated the anti-asthmatic potential of the Rho-kinase inhibitor hydroxyfasudil in the settings of allergen-induced allergen-induced experimental asthma.

METHODS

Chronic allergic airway inflammation was caused by 28 days-sensitisation of guinea pigs with ovalbumin (OVA). Hydroxyfasudil was administered intraperitoneally in two doses for the last two weeks (1 mg/kg b.w.; 10 mg/kg b.w.). The degree of allergic inflammation was determined based on concentrations of inflammatory Th2 cytokines (IL-4, IL-13), Th1 cytokines (TNF-α and IFN-γ) in the lung homogenate and leukocyte count in the bronchoalveolar lavage fluid (BALF). The markers of remodelling and fibrosis, the growth factors (TGF-β1, EGF), EGF receptor, collagen type III and V were estimated in lung homogenate. The changes in specific airway resistance (sRaw) were used as an in vivo bronchial hyperreactivity parameter.

RESULTS

Hydroxyfasudil administration at both doses significantly reduced sRaw after a week of therapy. We observed a decline of IL-13, TNF-α and IFN-γ in lung homogenate and a lower presence of lymphocytes in BALF after 14 days of hydroxyfasudil administration at both tested doses. Hydroxyfasudil 14 days-treatment at both doses effectively reduced the concentrations of TGF-β1, EGF receptors, collagen type III and V in BALF and modulated EGF levels.

CONCLUSIONS

These findings indicate that RhoA/Rho-kinase is involved in the pathophysiology of allergic airway inflammation and suggest that Rho-kinase inhibitor hydroxyfasudil has therapeutic potential for asthma management.

A visualization system for erectile vascular dynamics

Erection is an essential process which requires the male penis for copulation. This copulatory process depends on the vascular dynamic regulation of the penis. The corpus cavernosum (CC) in the upper (dorsal) part of the penis plays a major role in regulating blood flow inside the penis. When the CC is filled with blood, the sinusoids, including micro-vessels, dilate during erection. The CC is an androgen-dependent organ, and various genital abnormalities including erectile dysfunction (ED) are widely known. Previous studies have shown that androgen deprivation by castration results in significantly decreased smooth muscles of the CC. Experimental works in erectile biology have previously measured intracavernosal penile pressure and mechanical tension. Such reports analyze limited features without assessing the dynamic aspects of the erectile process. In the current study, we established a novel explant system enabling direct visual imaging of the sinusoidal lumen to evaluate the dynamic movement of the cavernous space. To analyze the alternation of sinusoidal spaces, micro-dissected CC explants by patent blue dye injection were incubated and examined for their structural alternations during relaxation/contraction. The dynamic process of relaxation/contraction was analyzed with various external factors administered to the CC. The system enabled the imaging of relaxation/contraction of the lumens of the sinusoids and the collagen-containing tissues. Histological analysis on the explant system also showed the relaxation/contraction. Thus, the system mimics the regulatory process of dynamic relaxation/contraction in the erectile response. The current system also enabled evaluating the erectile pathophysiology. In the current study, the lumen of sinusoids relaxed/contracted in castrated mice similarly with normal mice. These results suggested that the dynamic erectile relaxation/contraction process was similarly retained in castrated mice. However, the system also revealed decreased duration time of erection in castrated mice. The current study is expected to promote further understanding of the pathophysiology of ED, which will be useful for new treatments in the future. Hence, the current system provides unique information to investigate the novel regulations of erectile function, which can provide tools for analyzing the pathology of ED.

Molecular pathogenesis and treatment of cavernous nerve injury-induced erectile dysfunction: A narrative review

Introduction: Erectile dysfunction (ED) is a common complication after radical prostatectomy (RP), and it seriously affects the quality of life in patients and their partners. The primary trigger of postoperative ED is surgical injury to the cavernous nerves that control penile erection and run along the anterolateral aspect of the prostate. Despite the introduction and ongoing innovation of nerve-sparing techniques, a significant number of patients still suffer from moderate cavernous nerve injury (CNI), which is thought to be transient and reversible. Therefore, early postoperative penile rehabilitation therapy may salvage patients’ erectile function by promoting cavernous nerve regeneration and preventing penile structural alterations.

Aims: To present a comprehensive overview of the current molecular pathogenesis of CNI-induced ED, as well as novel therapeutic strategies and their potential mechanisms.

Methods: A literature search was performed using PubMed. Search terms included erectile dysfunction, cavernous nerve injury, pathogenesis, pathway, and treatment.

Results: The NOS/NO pathway, oxidative stress-related pathway, RhoA/ROCK pathway, transforming growth factor-β (TGF-β), sonic hedgehog (Shh), and hydrogen sulfide (H2S) are involved in the molecular pathogenesis of CNI-induced ED. Multiple neurotrophins, including brain-derived nerve growth factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), and neurturin (NTN), were found to promote cavernous nerve regeneration. Emerging therapeutic approaches can be roughly summarized into four categories, namely small molecule and drug, stem cell-based therapy (SCT), micro-energy therapy and platelet-rich plasma (PRP) therapy.

Conclusion: These pathways collectively lead to the irreversible damage to the penile structure after CNI. The combined early rehabilitation strategies of promoting upstream nerve regeneration and recovering abnormal molecular signals of downstream penis are presumed to save patients’ erectile function after RP. In future studies, the cross-talk between these molecular pathways needs to be further clarified, and the questions of how denervation injury induces the molecular alterations in the penis also need to be addressed.

Tacrolimus Causes Hypertension by Increasing Vascular Contractility via RhoA (Ras Homolog Family Member A)/ROCK (Rho-Associated Protein Kinase) Pathway in Mice

BACKGROUND

To provide tacrolimus is first-line treatment after liver and kidney transplantation. However, hypertension and nephrotoxicity are common tacrolimus side effects that limit its use. Although tacrolimus-related hypertension is well known, the underlying mechanisms are not. Here, we test whether tacrolimus-induced hypertension involves the RhoA (Ras homolog family member A)/ROCK (Rho-associated protein kinase) pathway in male C57Bl/6 mice.

METHODS

Intra-arterial blood pressure was measured under anesthesia. The reactivity of renal afferent arterioles and mesenteric arteries were assessed in vitro using microperfusion and wire myography, respectively.

RESULTS

Tacrolimus induced a transient rise in systolic arterial pressure that was blocked by the RhoA/ROCK inhibitor Fasudil (12.0±0.9 versus 3.2±0.7; P<0.001). Moreover, tacrolimus reduced the glomerular filtration rate, which was also prevented by Fasudil (187±20 versus 281±8.5; P<0.001). Interestingly, tacrolimus enhanced the sensitivity of afferent arterioles and mesenteric arteries to Ang II (angiotensin II), likely due to increased intracellular Ca²⁺ mobilization and sensitization. Fasudil prevented increased Ang II-sensitivity and blocked Ca²⁺ mobilization and sensitization. Preincubation of mouse aortic vascular smooth muscle cells with tacrolimus activated the RhoA/ROCK/MYPT-1 (myosin phosphatase targeting subunit 1) pathway. Further, tacrolimus increased cytoplasmic reactive oxygen species generation in afferent arterioles (107±5.9 versus 163±6.4; P<0.001) and in cultured mouse aortic vascular smooth muscle cells (100±7.5 versus 160±23.2; P<0.01). Finally, the reactive oxygen species scavenger Tempol inhibited tacrolimus-induced Ang II hypersensitivity in afferent arterioles and mesenteric arteries.

CONCLUSIONS

The RhoA/ROCK pathway may play an important role in tacrolimus-induced hypertension by enhancing Ang II-specific vasoconstriction, and reactive oxygen species may participate in this process by activating the RhoA/ROCK pathway.

Parthenolide modulates cerebral ischemia-induced microglial polarization and alleviates neuroinflammatory injury via the RhoA/ROCK pathway

BACKGROUND

Microglia can be activated as proinflammatory (M1) phenotypes and anti-inflammatory (M2) phenotypes after stroke. Parthenolide (PTL) has anti-inflammatory and protective effects on neurological diseases, but until now, the exact mechanisms of these processes after stroke have been unclear. The purpose of this study was to determine the effect of PTL on microglial polarization after stroke and its target for inducing microglial polarization.

METHODS

Triphenyltetrazolium chloride (TTC) staining, hematoxylin-eosin (HE) staining, and neurological evaluation were performed in a focal transient cerebral ischemia rat model. The human microglia exposed to lipopolysaccharide (LPS) was used for in vitro experiments. Microglial polarization was assessed by RT-PCR and immunostaining. Inflammatory cytokine assays and western blotting were used to investigate the molecular mechanisms underlying PTL-mediated microglial polarization in vivo and in vitro.

RESULTS

PTL significantly reduced cerebral infarction and neuronal apoptosis in rats with cerebral ischemia, reduced the level of inflammatory factors and alleviated neurological deficits. PTL treatment decreased the expression of microglia/macrophage markers in M1 macrophages and increased the expression of microglia/macrophage markers in M2 macrophages after stroke, which induced the transformation of microglia cells from the M1 phenotype to the M2 phenotype. Furthermore, PTL significantly reduced RhoA/ROCK-NF-κB pathway activity and downregulated the effects of pentanoic acid (ROCK agonist).

CONCLUSIONS

PTL has been shown to mediate neuroinflammation and protect against ischemic brain injury by regulating microglial polarization via the RhoA/ROCK pathway.

Targeting the LPA1 signalling pathway for fibrosis therapy: a patent review (2010-present)

INTRODUCTION

Fibrosis is a disease that damages organs and even causes death. Because of the complicated pathogenesis, the development of drugs for fibrosis is challenging. In the lysophosphatidic acid receptor type 1 (LPA1) signalling pathway, LPA1 and its downstream Rho-associated coiled-coil forming protein kinase (ROCK) are related to the process of fibrosis. Targeting LPA1 signalling pathway is a potential strategy for the treatment of fibrosis.

AREA COVERED

This review describes the process of fibrosis mediated by the LPA1 signalling pathway and then summarizes LPA1 antagonist patents reported since 2010 and ROCK inhibitor patents since 2017 according to their scaffolds based on the Cortellis Drug Discovery Intelligence database. Information on LPA1 antagonists entering clinical trials is integrated.

EXPERT OPINION

Over the past decade, a large number of antagonists targeting the LPA1 signalling pathway have been patented for fibrosis therapy. A limited number of compounds have entered clinical trials. Different companies and research groups have used different scaffolds when designing compounds for fibrosis therapy. Therefore, LPA1 and ROCK are competitive targets for the development of new therapies for fibrosis to provide a potential treatment method for fibrosis in the future.

Role of Endothelin-1 in Right Atrial Arrhythmogenesis in Rabbits with Monocrotaline-Induced Pulmonary Arterial Hypertension

Atrial arrhythmias are considered prominent phenomena in pulmonary arterial hypertension (PAH) resulting from atrial electrical and structural remodeling. Endothelin (ET)-1 levels correlate with PAH severity and are associated with atrial remodeling and arrhythmia. In this study, hemodynamic measurement, western blot analysis, and histopathology were performed in the control and monocrotaline (MCT, 60 mg/kg)-induced PAH rabbits. Conventional microelectrodes were used to simultaneously record the electrical activity in the isolated sinoatrial node (SAN) and right atrium (RA) tissue preparations before and after ET-1 (10 nM) or BQ-485 (an ET-A receptor antagonist, 100 nM) perfusion. MCT-treated rabbits showed an increased relative wall thickness in the pulmonary arterioles, mean cell width, cross-sectional area of RV myocytes, and higher right ventricular systolic pressure, which were deemed to have PAH. Compared to the control, the spontaneous beating rate of SAN–RA preparations was faster in the MCT-induced PAH group, which can be slowed down by ET-1. MCT-induced PAH rabbits had a higher incidence of sinoatrial conduction blocks, and ET-1 can induce atrial premature beats or short runs of intra-atrial reentrant tachycardia. BQ 485 administration can mitigate ET-1-induced RA arrhythmogenesis in MCT-induced PAH. The RA specimens from MCT-induced PAH rabbits had a smaller connexin 43 and larger ROCK1 and phosphorylated Akt than the control, and similar PKG and Akt to the control. In conclusion, ET-1 acts as a trigger factor to interact with the arrhythmogenic substrate to initiate and maintain atrial arrhythmias in PAH. ET-1/ET-A receptor/ROCK signaling may be a target for therapeutic interventions to treat PAH-induced atrial arrhythmias.

Belumosudil, ROCK2-Specific Inhibitor, alleviates cardiac fibrosis by inhibiting cardiac fibroblasts activation

Cardiac fibrosis is thought to be the hallmark of pathological hypertrophic remodeling, of which the myofibroblasts transdifferentiation is the key cell biological event. However, there is still no specific and effective therapeutic agent approved for cardiac fibrosis. To investigate the effects of Belumosudil, the first ROCK2-specific inhibitor, on cardiac hypertrophy, fibrosis and dysfunction induced by pressure overload, the transverse aortic constriction (TAC) or sham operation was carried out on wild-type C57BL/6 mice (male, 6-8 week old) under pentobarbital anesthesia. After that, mice were randomly divided into three groups: sham operation + vehicle, TAC + vehicle, TAC + 50 mg·kg^-1·d^-1 Belumosudil. We found that Belumosudil effectively ameliorated cardiac hypertrophy, fibrosis and dysfunction in TAC mice. To elucidate the underlying mechanism, we inhibited the expression of ROCK2 in vitro by either Belumosudil or siRNA. We showed that the inhibition of ROCK2 by either Belumosudil or knockdown suppressed cardiac fibroblasts activation and proliferation significantly induced by Transforming Growth Factor-β1 (TGF-β1). Furthermore, our study confirmed ROCK2 mediates cardiac fibrosis by interacting with Transforming Growth Factor-β1 (TGF-β1)/mothers against decapentaplegic homolog (Smad2) pathway. Taken together, we demonstrated that Belumosudil ameliorates cardiac hypertrophy and fibrosis induced by TAC via inhibiting cardiac fibroblasts activation. In conclusion, Belumosudil may be a promising therapeutic drug for cardiac hypertrophy and fibrosis induced by myocardial pressure overload.

The ROCK-ezrin signaling pathway mediates LPS-induced cytokine production in pulmonary alveolar epithelial cells

BACKGROUND

Ezrin/radixin/moesin (ERM) proteins are members of the protein 4.1 superfamily and function as linkers that connect the actin cytoskeleton to the plasma membrane of cells. ERM also play critical role in the Lipopolysaccharide (LPS)-induced inflammatory response. However, the signaling mechanisms involved in this process remain unclear. In this study, we aimed to investigate the potential role of the rho-associated coiled-coil containing protein kinase (ROCK) pathway in LPS-induced ezrin phosphorylation and cytokine production in pulmonary alveolar epithelial cells.

METHODS

Cultured A549 and HPAEpiC cells were treated with LPS. The expression and localization of ezrin in A549 and HPAEpiC cells were then analyzed by western blotting and immunoflurescence. Activation of RhoA/ROCK was assessed by western blotting and RhoA activity assays. The interaction of ezrin with Syk and myeloid differentiation factor 88 (MyD88)/IL-1R-associated kinase 1 (IRAK-1) was investigated by co-immunoprecipitation. The activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) was measured with electrophoretic mobility shift assays and by western blotting. ELISA and western blotting were performed to detect the levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and high mobility group box 1 protein (HMGB1) release into the culture supernatant, and cellular HMGB1 levels.

RESULTS

LPS induced ezrin phosphorylation in a concentration- and time-dependent manner. The blockade of RhoA/ROCK inhibited LPS-induced ezrin phosphorylation and its translocation from the cytoplasm to the cell membrane. Co-immunoprecipitation assays further revealed that ezrin associated with Syk constitutively, but only associated with MyD88/IRAK-1 upon LPS challenge. Moreover, LPS-induced p38 and nuclear NF-κB activation was found to be ezrin dependent. The suppression of ezrin by siRNA or the blockade of ROCK activation with Y-27632 reduced the production of TNF-α, IL-1β, and HMGB1 in response to LPS.

CONCLUSIONS

Our findings reveal a novel regulatory mechanism involving ezrin in the LPS-induced production of pro-inflammatory cytokines, and highlight the importance of the RhoA/ROCK-ezrin/Syk-MyD88/IRAK1 axis. Data presented in this manuscript provide novel insights into the signaling pathways activated in pulmonary alveolar epithelial cells by LPS. Video Abstract.

Dual efficacy of Fasudil at improvement of survival and reinnervation of flap through RhoA/ROCK/PI3K/Akt pathway

Fasudil is reported to be effective at protecting against ischaemic diseases, and at augmenting axon growth. In this study, we aim to evaluate its efficacy in promoting flap survival and reinnervation. Ninety-two Institute of Cancer Research (ICR) mice were used and divided into the control, Fasudil, LY294002, Fasudil+LY294002 groups, receiving a daily intraperitoneal injection of normal saline, Fasudil (10 mg/kg), LY294002 (5 mg/kg), and Fasudil (10 mg/kg) + LY294002 (5 mg/kg), respectively. On days 0 and 5, the blood perfusion and diameter of the iliolumbar artery in the pedicle of the flaps in the four groups were evaluated using laser speckling contrast imaging (LSCI). On day 5, the flaps were photographed and the necrosis rate of the flaps was calculated using Photoshop CS6. In addition, tissues were harvested from the flaps and divided into two parts. One part underwent routine cryosection and immunofluorescent staining using the antibody against CD31 for evaluation of the microvascular density in the four groups. In the other part, the expression of RhoA, ROCK1+2, p-CPI-17, p-MYPT, p-PTEN, p-PI3K, p-Akt, and vascular endothelial growth factor (VEGF) within the flaps were determined using western blotting. Moreover, at days 0, 7, 15, and 30 after flap surgery, the axons within the flaps were evaluated using immunofluorescent staining with the antibody against Neurofilament-200. It turned out that the necrosis rate was (24.4 ± 7.7)%, (5.2 ± 1.6)%, (29.8 ± 4.2)%, and (30.9 ± 7.1)%, respectively, in the control, Fasudil, LY294002, LY294002+Fasudil groups. There was a significant reduction in the necrosis rate of the flaps in the Fasudil group (P < .001). The LSCI and immunofluorescent staining demonstrated that Fasudil could significantly expand the diameter of the iliolumbar artery in the pedicle, boost the overall blood perfusion, and increase the microvascular density of the flaps in the Fasudil group (P < .05), which could all be abolished by PI3K inhibitor LY294002. On day 5, the expression of p-CPI-17, p-MYPT, and p-PTEN were downregulated, whereas pPI3K, p-Akt, and VEGF were upregulated in the Fasudil group (P < .001). As for reinnervation, Neurofilament-200 fluorescent staining revealed that at days 15 and 30 after flap harvest, only in the Fasudil group could new axons be observed. It can be concluded that Fasudil could simultaneously improve the survival and axon growth after flap harvest, a dual efficacy achieved by inhibition of the RhoA/ROCK pathway, which in turn activates /PI3K/AKT pathway.

Vascular smooth muscle ROCK1 contributes to hypoxia-induced pulmonary hypertension development in mice

Rho kinase (ROCK) is implicated in the development of pulmonary arterial hypertension (PAH) in which abnormal pulmonary vascular smooth muscle (VSM) contractility and remodeling lead to right heart failure. Pharmacologic ROCK inhibitors block experimental pulmonary hypertension (PH) development in rodents but can have off-target effects and do not distinguish between the two ROCK forms, ROCK1 and ROCK2, encoded by separate genes. An earlier study using gene knock out (KO) in mice indicated that VSM ROCK2 is required for experimental PH development, but the role of ROCK1 is not well understood. Here we investigated the in vivo role of ROCK1 in PH development by generating a VSM-targeted homozygous ROCK1 gene KO mouse strain. Adult control mice exposed to Sugen5416 (Su)/hypoxia treatment to induce PH had significantly increased right ventricular systolic pressures (RVSP) and RV hypertrophy versus normoxic controls. In contrast, Su/hypoxia-exposed VSM ROCK1 KO mice did not exhibit significant RVSP elevation, and RV hypertrophy was blunted. Su/hypoxia-induced pulmonary small vessel muscularization was similarly elevated in both control and VSM ROCK1 KO animals. siRNA-mediated ROCK1 knock-down (KD) in human PAH pulmonary arterial SM cells (PASMC) did not affect cell growth. However, ROCK1 KD led to reduced AKT and MYPT1 signaling in serotonin-treated PAH PASMC. The findings suggest that like VSM ROCK2, VSM ROCK1 actively contributes to PH development, but in distinction acts via nonproliferative pathways to promote hypoxemia, and thus may be a distinct therapeutic target in PH.

An Integrated Proteomics and Metabolomics Strategy for the Mechanism of Calcium Oxalate Crystal-Induced Kidney Injury

Renal fibrosis is the pathological repair reaction of the kidney to chronic injury, which is an important process of chronic kidney disease (CKD) progressing to end-stage renal failure. Nephrolithiasis is one of the most common renal diseases, with waist and abdomen pain, hematuria, urinary tract infection, and other clinical symptoms, which can increase the risk of renal fibrosis. Oxalate crystal-induced kidney injury is an early stage of nephrolithiasis; it is of great significance to explore the mechanism for the prevention and treatment of nephrolithiasis. A rodent model of calcium oxalate (CaOx) crystal-induced kidney injury was used in the present study, and a network analysis method combining proteomics and metabolomics was conducted to reveal the mechanism of crystal kidney injury and to provide potential targets for the intervention of nephrolithiasis. Using the metabolomics method based on the UHPLC-Q/TOF-MS platform and the iTRAQ quantitative proteomics method, we screened a total of 244 metabolites and 886 proteins from the kidney tissues that had significant changes in the Crystal group compared with that in the Control group. Then, the ingenuity pathway analysis (IPA) was applied to construct a protein-to-metabolic regulatory network by correlating and integrating differential metabolites and proteins. The results showed that CaOx crystals could induce inflammatory reactions and oxidative stress through Akt, ERK1/2, and P38 MAPK pathways and affect amino acid metabolism and fatty acid β-oxidation to result in kidney injury, thus providing an important direction for the early prevention and treatment of nephrolithiasis.

Carvedilol alleviates lipopolysaccharide (LPS)-induced acute lung injury by inhibiting Ras homolog family member A (RhoA)/ROCK activities

Carvedilol possess multiple functions such as antioxidation and neuroprotection RhoA/ROCK is reported to participate in acute lung injury (ALI). The aim of the present study was to explore the role of carvedilol in LPS-induced ALI. BEAS2B cells were subjected to LPS for the construction of in vitro ALI model. After that, the protective effects of carvedilol were evaluated by Cell Counting Kit-8 (CCK-8). The activities of RhoA/ROCK were then measured to confirm its association with carvedilol by quantitative reverse transcription PCR (RT-qPCR) and Western blot. Then, the cell viability, inflammatory responses, oxidative stress and apoptosis were detected by CCK-8, enzyme linked immunosorbent assay (ELISA), oxidative stress detection kits, and TdT-mediated dUTP Nick-End Labeling (TUNEL) respectively. Inflammation- and apoptosis-related markers were also measured by Western blot. The cell viability reduced by LPS in BEAS2B cells was elevated by carvedilol. Moreover, RhoA/ROCK were found to be suppressed by carvedilol administration. The cell viability, inflammation, oxidative stress and apoptosis of LPS-induced BEAS2B cells were aggravated upon RhoA was overexpressed. Collectively, carvedilol exerts a protective effect against LPS-induced injury that could be ascribed to its anti-inflammatory and antioxidative character through modulating the RhoA/ROCK activities.

Molecular Action of Herbal Medicine in Physiology of Erection and its Dysfunction

Erection is a physiological process that involves vascular, hormonal, and nervous factors. Erectile dysfunction is one of the male sexual problems that occur globally and is reported to affect men's quality of life. Herbal plants have been widely used for disease treatment, including the problem of erectile dysfunction. This paper aims to review the molecular potential of various plants in the physiology of erection and to treat erectile dysfunction. The literature search was carried out through the Pubmed and Google Scholar databases regarding the molecular mechanisms of herbal plants and their potential involvement in the physiology of erection and overcoming erectile dysfunction. This paper focuses on six herbal plants: Panax ginseng, Ginkgo biloba, Epimedium, Black pepper, Tribulus terrestris, and Eurycoma longifolia. The six herbal plants have involvement in the erection process and have molecular potential in the treatment of erectile problems

Novel engineered, membrane-tethered VEGF-A variants promote formation of filopodia, proliferation, survival, and cord or tube formation by endothelial cells via persistent VEGFR2/ERK signaling and activation of CDC42/ROCK pathways

Therapeutic angiogenesis would be clinically valuable in situations such as peripheral vascular disease in diabetic patients and tissue reperfusion following ischemia or injury, but approaches using traditional isoforms of vascular endothelial growth factor-A (VEGF) have had little success. The isoform VEGF165 is both soluble and matrix-associated, but can cause pathologic vascular changes. Freely diffusible VEGF121 is not associated with pathologic angiogenesis, but its failure to remain in the vicinity of the targeted area presents therapeutic challenges. In this study, we evaluate the cellular effects of engineered VEGF variants that tether extracellular VEGF121 to the cell membrane with the goal of activating VEGF receptor 2 (VEGFR2) in a sustained, autologous fashion in endothelial cells. When expressed by primary human retinal endothelial cells (hRECs), the engineered, membrane-tethered variants eVEGF-38 and eVEGF-53 provide a lasting VEGF signal that induces cell proliferation and survival, increases endothelial permeability, promotes the formation of a cord/tube network, and stimulates the formation of elongated filopodia on the endothelial cells. The engineered VEGF variants activate VEGFR2, MAPK/ERK, and the Rho GTPase mediators CDC42 and ROCK, activities that are required for the formation of the elongated filopodia. The sustained, pro-angiogenic activities induced by eVEGF-38 and eVEGF-53 support the potential of engineered VEGF variants-overexpressing endothelial cells as a novel combination of gene and cell-based therapeutic strategy for stimulating endothelial cell-autologous therapeutic angiogenesis.

The role of daurisoline treatment in hepatocellular carcinoma: Inhibiting vasculogenic mimicry formation and enhancing sensitivity to sorafenib

BACKGROUND

Vasculogenic mimicry (VM) is a newly described tumor vascular phenomenon that is independent of traditional angiogenesis and provides an adequate blood supply for tumor growth. VM has been consistently observed in different cancer types. Hence, inhibition of VM may be considered a new anticancer therapeutic strategy.

PURPOSE

This study aimed to elucidate the potential anticancer effect of daurisoline (DS) on hepatocellular carcinoma (HCC) and the potential molecular mechanism by which DS inhibits VM. We also verified whether combination treatment with sorafenib and DS constitutes a novel therapeutic approach to prevent HCC progression.

METHODS

The effects of DS on proliferation were evaluated by Cell Counting Kit-8 (CCK-8), colony formation, and 5-ethynyl-2'-deoxyuridine (EdU) incorporation assays. 4',6-Diamidino-2-phenylindole (DAPI) staining and flow cytometric analysis were employed to investigate its effects on apoptosis. Western blot analysis, Matrigel tube formation assays, pulldown assays and immunofluorescence staining were applied to validate the potential mechanism by which DS inhibits VM. Mouse xenograft models were used to evaluate anticancer activities.

RESULTS

DS inhibited HCC cell proliferation, induced HCC cell apoptosis and repressed VM formation by inactivating RhoA/ROCK2-mediated AKT and ERK-p38 MAPK signaling. Additionally, DS dramatically sensitized HCC cell lines to sorafenib, a curative anticancer drug for patients with advanced HCC.

CONCLUSIONS

Our study provides insights into the molecular mechanisms underlying DS-induced inhibition of VM, which may facilitate the development of a novel clinical anti-HCC drug. Moreover, our findings suggest that the combination of DS and sorafenib constitutes a potential therapeutic strategy for HCC.

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.