RhoA/Rho-kinases in asthma: from pathogenesis to therapeutic targets

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.

Stiffness Mediated-Mechanosensation of Airway Smooth Muscle Cells on Linear Stiffness Gradient Hydrogels

In obstructive airway diseases such as asthma and chronic obstructive pulmonary disease (COPD), the extracellular matrix (ECM) protein amount and composition of the airway smooth muscle (ASM) is often remodelled, likely altering tissue stiffness. The underlying mechanism of how human ASM cell (hASMC) mechanosenses the aberrant microenvironment is not well understood. Physiological stiffnesses of the ASM were measured by uniaxial compression tester using porcine ASM layers under 0, 5 and 10% longitudinal stretch above in situ length. Linear stiffness gradient hydrogels (230 kPa range) were fabricated and functionalized with ECM proteins, collagen I (ColI), fibronectin (Fn) and laminin (Ln), to recapitulate the above-measured range of stiffnesses. Overall, hASMC mechanosensation exhibited a clear correlation with the underlying hydrogel stiffness. Cell size, nuclear size and contractile marker alpha-smooth muscle actin (αSMA) expression showed a strong correlation to substrate stiffness. Mechanosensation, assessed by Lamin-A intensity and nuc/cyto YAP, exhibited stiffness-mediated behaviour only on ColI and Fn-coated hydrogels. Inhibition studies using blebbistatin or Y27632 attenuated most mechanotransduction-derived cell morphological responses, αSMA and Lamin-A expression and nuc/cyto YAP (blebbistatin only). This study highlights the interplay and complexities between stiffness and ECM protein type on hASMC mechanosensation, relevant to airway remodelling in obstructive airway diseases.

Rho-Kinase Inhibition of Active Force and Passive Tension in Airway Smooth Muscle: A Strategy for Treating Airway Hyperresponsiveness in Asthma

Rho-kinase inhibitors have been identified as a class of potential drugs for treating asthma because of their ability to reduce airway inflammation and active force in airway smooth muscle (ASM). Past research has revealed that, besides the effect on the ASM's force generation, rho-kinase (ROCK) also regulates actin filament formation and filament network architecture and integrity, thus affecting ASM's cytoskeletal stiffness. The present review is not a comprehensive examination of the roles played by ROCK in regulating ASM function but is specifically focused on passive tension, which is partially determined by the cytoskeletal stiffness of ASM. Understanding the molecular basis for maintaining active force and passive tension in ASM by ROCK will allow us to determine the suitability of ROCK inhibitors and its downstream enzymes as a class of drugs in treating airway hyperresponsiveness seen in asthma. Because clinical trials using ROCK inhibitors in the treatment of asthma have yet to be conducted, the present review focuses on the in vitro effects of ROCK inhibitors on ASM's mechanical properties which include active force generation, relaxation, and passive stiffness. The review provides justification for future clinical trials in the treatment of asthma using ROCK inhibitors alone and in combination with other pharmacological and mechanical interventions.

Vascular endothelial growth factor induces the migration of human airway smooth muscle cells by activating the RhoA/ROCK pathway

BACKGROUND

Airway remodeling due to increased airway smooth muscle cell (ASMC) mass, likely due to enhanced proliferation, hypertrophy, and migration, has been proven to be highly correlated with decreased lung function in asthma patients. Vascular endothelial growth factor (VEGF) mediates vascular and extravascular remodeling and inflammation and has been proven to be involved in the progression of asthma. Previous studies have focused on the effects of VEGF on ASMC proliferation, but few researchers have focused on the effects of VEGF on human ASMC migration. The purpose of this study was to explore the effect of VEGF on the migration of ASMCs and its related signaling pathway mechanism to provide evidence for the treatment of airway remodeling.

METHODS

We examined the effects of VEGF induction on ASMC migration and explored the mechanisms involved in ASMC migration.

RESULTS

We found by wound healing and Transwell assays that VEGF promoted ASMC migration. Through the Cell Counting Kit-8 (CCK-8) experiment, we found that VEGF had no significant effect on the proliferation of ASMCs, which excluded the involvement of cell proliferation in the process of wound healing. Moreover, a cellular immunofluorescence assay showed that VEGF promoted F-actin reorganization, and Western blotting showed that VEGF improved RhoA activation and myosin phosphatase targeting subunit-1 (MYPT1) and myosin light chain (MLC) phosphorylation in ASMCs. Treatment with the ROCK inhibitor Y27632 significantly attenuated the effects of VEGF on MYPT1/MLC activation and cell migration.

CONCLUSION

In conclusion, the results suggest that the promigratory function of VEGF activates the RhoA/ROCK pathway, induces F-actin reorganization, improves the migration of ASMCs, and provides a better rationale for targeting the RhoA/ROCK pathway for therapeutic approaches in airway remodeling.

Fasudil and SR1001 synergistically protect against sepsis-associated pancreatic injury by inhibiting RhoA/ROCK pathway and Th17/IL-17 response

Sepsis is defined as a dysregulated host response to infection that can result in organ dysfunction and high mortality, which needs more effective treatment urgently. Pancreas is one of the most vulnerable organs in sepsis, resulting in sepsis-associated pancreatic injury, which is a fatal complication of sepsis. The aim of this study was to investigate the effect of combination of fasudil and SR1001 on sepsis-associated pancreatic injury and to explore the underlying mechanisms. The model of sepsis-associated pancreatic injury was induced by cecal ligation and puncture. Pancreatic injury was evaluated by HE staining, histopathological scores and amylase activity. The frequency of Th17 cells was analyzed by flow cytometry. Serum IL-17 level was determined by ELISA. Protein levels of RORγt, p-STAT3, GEF-H1, RhoA and ROCK1 were determined by Western blot. The apoptosis of pancreatic cells was examined by TUNEL analysis and Hoechst33342/PI staining. Compared to the sham group, the model group showed significant pathological injury including edema, hyperemia, vacuolization and necrosis. After treatment with fasudil, model mice showed an obvious reduction of Th17 cells and IL-17. SR1001 significantly reduced the expressions of GEF-H1, RhoA and ROCK1 in the model mice. The combination treatment with fasudil and SR1001 significantly inhibited the differentiation of Th17 cells, expressions of IL-17, GEF-H1, RhoA and ROCK1, which were more effective than each mono-treatment. In addition, our data revealed a remarkable decrease of apoptosis in pancreatic acinar cells culturing with fasudil or SR1001, which was further inhibited by their combination culture. Lipopolysaccharide remarkably upregulated the differentiation of Th17 cells in vitro, which could be significantly downregulated by fasudil or SR1001, and further downregulated by their combination treatment. Taken together, the combination of fasudil with SR1001 has a synergistic effect on protecting against sepsis-associated pancreatic injury in C57BL/6 mice.

Effects of Oxidative Stress on Airway Epithelium Permeability in Asthma and Potential Implications for Patients with Comorbid Obesity

20 million adults and 4.2 million children in the United States have asthma, a disease resulting in inflammation and airway obstruction in response to various factors, including allergens and pollutants and nonallergic triggers. Obesity, another highly prevalent disease in the US, is a major risk factor for asthma and a significant cause of oxidative stress throughout the body. People with asthma and comorbid obesity are susceptible to developing severe asthma that cannot be sufficiently controlled with current treatments. More research is needed to understand how asthma pathobiology is affected when the patient has comorbid obesity. Because the airway epithelium directly interacts with the outside environment and interacts closely with the immune system, understanding how the airway epithelium of patients with asthma and comorbid obesity is altered compared to that of lean asthma patients will be crucial for developing more effective treatments. In this review, we discuss how oxidative stress plays a role in two chronic inflammatory diseases, obesity and asthma, and propose a mechanism for how these conditions may compromise the airway epithelium.

Targeting the RhoA-GEF-H1 pathway of mast cells attenuates experimental airway allergy

Mast cells are the major effector cells in allergic diseases. RhoA and its downstream pathway is associated with the pathogenesis of airway allergy. The objective of this study is to test a hypothesis that modulating the RhoA-GEF-H1 axis in mast cells can attenuate airway allergy. An airway allergic disorder (AAD) mouse model was employed. Mast cells were isolated from AAD mouse airway tissues to be analyzed by RNA sequencing. We observed that mast cells isolated from the respiratory tract of AAD mice were resistant to apoptosis. Mast cell mediator levels in nasal lavage fluid were correlated with apoptosis resistance in AAD mice. Activation of RhoA in AAD mast cells was related to resistance to apoptosis. Mast cells isolated from the airway tissues in AAD mouse exhibited strong RhoA-GEF-H1 expression. The RhoA-GEF-H1 axis was associated with the lower FasL expression in AAD mast cells. Activation of the RhoA-GEF-H1 axis promoted the production of mediators in mast cells. Inhibition of GEF-H1 facilitated the SIT-induced mast cell apoptosis and enhanced the therapeutic efficacy of AAD. In conclusion, RhoA-GEF-H1 activities are associated with resistance to apoptosis in mast cells isolated from sites of allergic lesions. The state of apoptosis resistance in mast cells is associated with the state of AAD disease. Inhibition of GEF-H1 restores the sensitivity of mast cells to apoptosis inducers, and alleviates experimental AAD in mice.

Myocd regulates airway smooth muscle cell remodeling in response to chronic asthmatic injury

Abnormal growth of airway smooth muscle cells is one of the key features in asthmatic airway remodeling, which is associated with asthma severity. The mechanisms underlying inappropriate airway smooth muscle cell growth in asthma remain largely unknown. Myocd has been reported to act as a key transcriptional coactivator in promoting airway-specific smooth muscle development in fetal lungs. Whether Myocd controls airway smooth muscle remodeling in asthma has not been investigated. Mice with lung mesenchyme-specific deletion of Myocd after lung development were generated, and a chronic asthma model was established by sensitizing and challenging the mice with ovalbumin for a prolonged period. Comparison of the asthmatic pathology between the Myocd knockout mice and the wild-type controls revealed that abrogation of Myocd mitigated airway smooth muscle cell hypertrophy and hyperplasia, accompanied by reduced peri-airway inflammation, decreased fibrillar collagen deposition on airway walls, and attenuation of abnormal mucin production in airway epithelial cells. Our study indicates that Myocd is a key transcriptional coactivator involved in asthma airway remodeling. Inhibition of Myocd in asthmatic airways may be an effective approach to breaking the vicious cycle of asthmatic progression, providing a novel strategy in treating severe and persistent asthma. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Targeting epithelial cell-derived TWIST1 alleviates allergic asthma

It is well known that the T Helper (Th)2 bias plays a critical role in allergic asthma. Whereas the Th2 bias is maintained in the local tissues is uncertain. IL-33 is vital for the development of the Th2 polarization. TWIST-1 has an effect on regulating cellular functions. The aberrant activation of RAS sustains certain cellular activities. The aim of this study is to study the role of the interaction between activation of TWIST1 and RAS in inducing and maintaining Th2 polarization in allergic asthma. The epithelial cells of the airways (AEC) were isolated from the broncho-alveolar lavage fluids in patients with asthma. The mediators involved in the over-expression of IL-33 were determined by RNA sequencing. A mouse model was established to test the role of TWIST1 and RAS in developing allergic asthma. We observed a strong expression of TWIST1 in patients with allergic asthma that showed a positive correlation with asthmatic responses. TWIST1 favored the expression of the IL-33 in the AEC. Twist1-deficient AEC-carrying mice did not induce Th2 polarization in the airways. The expression TWIST1 in AECs was positively associated with RAS activation in AECs in patients with allergic asthma. The interaction between RAS and TWIST1 in AECs sustained airway allergic inflammation. Inhibition of TWIST1 or RAS prevented asthma-like inflammation in the mouse airways. In summary, the interaction between TWIST1 and RAS induces and maintains IL-33 expression in AECs to facilitate allergic inflammation in the respiratory tract. Inhibition of TWIST1 or RAS can prevent experimental allergic asthma.

Targeting of G-protein coupled receptor 40 alleviates airway hyperresponsiveness through RhoA/ROCK1 signaling pathway in obese asthmatic mice

Obesity increases the severity of airway hyperresponsiveness (AHR) in individuals with asthma, but the mechanism is not well elucidated. G-protein coupled receptor 40 (GPR40) has been found to induce airway smooth muscle contraction after activated by long-chain fatty acids (LC-FFAs), suggesting a close correlation between GPR40 and AHR in obese. In this study, C57BL/6 mice were fed a high-fat diet (HFD) to induce obesity with or without ovalbumin (OVA) sensitization, the regulatory effects of GPR40 on AHR, inflammatory cells infiltration, and the expression of Th1/Th2 cytokines were evaluated by using a small-molecule antagonist of GPR40, DC260126. We found that the free fatty acids (FFAs) level and GPR40 expression were greatly elevated in the pulmonary tissues of obese asthmatic mice. DC260126 greatly reduced methacholine-induced AHR, ameliorated pulmonary pathological changes and decreased inflammatory cell infiltration in the airways in obese asthma. In addition, DC260126 could down-regulate the levels of Th2 cytokines (IL-4, IL-5, and IL-13) and pro-inflammatory cytokines (IL-1β, TNF-α), but elevated Th1 cytokine (IFN-γ) expression. In vitro, DC260126 could remarkedly reduce oleic acid (OA)-induced cell proliferation and migration in HASM cells. Mechanistically, the effects that DC260126 alleviated obese asthma was correlated with the down-regulation of GTP-RhoA and Rho-associated coiled-coil-forming protein kinase 1 (ROCK1). Herein, we proved that targeting of GPR40 with its antagonist helped to mitigate multiple parameters of obese asthma effectively.

Airway smooth muscle in contractility and remodeling of asthma: potential drug target mechanisms

INTRODUCTION

Asthma is characterized by enhanced airway contractility and remodeling where airway smooth muscle (ASM) plays a key role, modulated by inflammation. Understanding the mechanisms by which ASM contributes to these features of asthma is essential for the development of novel asthma therapies.

AREAS COVERED

Inflammation in asthma contributes to a multitude of changes within ASM including enhanced airway contractility, proliferation, and fibrosis. Altered intracellular calcium ([Ca²⁺]_i) regulation or Ca²⁺ sensitization contributes to airway hyperreactivity. Increased airway wall thickness from ASM proliferation and fibrosis contributes to structural changes seen with asthma.

EXPERT OPINION

ASM plays a significant role in multiple features of asthma. Increased ASM contractility contributes to hyperresponsiveness, while altered ASM proliferation and extracellular matrix production promote airway remodeling both influenced by inflammation of asthma and conversely even influencing the local inflammatory milieu. While standard therapies such as corticosteroids or biologics target inflammation, cytokines, or their receptors to alleviate asthma symptoms, these approaches do not address the underlying contribution of ASM to hyperresponsiveness and particularly remodeling. Therefore, novel therapies for asthma need to target abnormal contractility mechanisms in ASM and/or the contribution of ASM to remodeling, particularly in asthmatics resistant to current therapies.

Therapeutic anti-amyloid β antibodies cause neuronal disturbances

INTRODUCTION

Recent published clinical trial safety data showed that 41% of Alzheimer patients experienced amyloid-related imaging abnormalities (ARIA), marks of microhemorrhages and edema in the brain, following administration of Biogen's Aduhelm/aducanumab (amino acids 3-7 of the Aβ peptide). Similarly, Janssen/Pfizer's Bapineuzumab (amino acids 1-5 of the Aβ peptide) and Roche's Gantenerumab (amino acids 2-11/18-27 of the Aβ peptide) also displayed ARIA in clinical trials, including microhemorrhage and focal areas of inflammation or vasogenic edema, respectively. The molecular mechanisms underlying ARIA caused by therapeutic anti-Aβ antibodies remain largely unknown, however, recent reports demonstrated that therapeutic anti-prion antibodies activate neuronal allergenic proteomes following cross-linking cellular prion protein.

METHODS

Here, we report that treatment of human induced pluripotent stem cells- derived neurons (HSCN) from a non-demented donor, co-cultured with human primary microglia with anti-Aβ1-6, or anti-Aβ17-23 antibodies activate a significant number of allergenic-related proteins as assessed by mass spectrometry.

RESULTS

Interestingly, a large proportion of the identified proteins included cytokines such as interleukin (IL)-4, IL-12, and IL-13 suggesting a type-1 hypersensitivity response. Following flow cytometry analysis, several proinflammatory cytokines were significantly elevated following anti-Aβ1-6, or anti-Aβ17-23 antibody treatment.

DISCUSSION

These results justify further and more robust investigation of the molecular mechanisms of ARIA during immunotherapy study trials of AD.

HIGHLIGHTS

Allergenic-related proteins are often linked with Alzheimer's disease (AD). We investigated the effects of amyloid beta (Aβ) immunotherapy on stem cell derived neurons and primary neuronal cells co-cultured with microglia. Anti-Aβ antibody treatment of neurons or neurons co-cultured with microglia led to activation of a substantial number of allergenic-related genes. These allergenic-related genes are associated with endothelial dysfunction possibly responsible for ARIA.

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.

HumanMine: advanced data searching, analysis and cross-species comparison

HumanMine (www.humanmine.org) is an integrated database of human genomics and proteomics data that provides a powerful interface to support sophisticated exploration and analysis of data compiled from experimental, computational and curated data sources. Built using the InterMine data integration platform, HumanMine includes genes, proteins, pathways, expression levels, Single nucleotide polymorphism (SNP), diseases and more, integrated into a single searchable database. HumanMine promotes integrative analysis, a powerful approach in modern biology that allows many sources of evidence to be analysed together. The data can be accessed through a user-friendly web interface as well as a powerful, scriptable web service Application programming interface (API) to allow programmatic access to data. The web interface includes a useful identifier resolution system, sophisticated query options and interactive results tables that enable powerful exploration of data, including data summaries, filtering, browsing and export. A set of graphical analysis tools provide a rich environment for data exploration including statistical enrichment of sets of genes or other biological entities. HumanMine can be used for integrative multistaged analysis that can lead to new insights and uncover previously unknown relationships.

Database URL: https://www.humanmine.org

Phytochemical Profiling and Bio-Potentiality of Genus Scutellaria: Biomedical Approach

Scutellaria (Lamiaceae) comprises over 360 species. Based on its morphological structure of calyx, also known as Skullcap, it is herbaceous by habit and cosmopolitan by habitat. The species of Scutellaria are widely used in local communities as a natural remedy. The genus contributed over three hundred bioactive compounds mainly represented by flavonoids and phenols, chemical ingredients which serve as potential candidates for the therapy of various biological activities. Thus, the current review is an attempt to highlight the biological significance and its correlation to various isolated bioactive ingredients including flavonoids, terpenoids, phenols, alkaloids, and steroids. However, flavonoids were the dominant group observed. The findings of the Scutellaria reveal that due to its affluent basis of numerous chemical ingredients it has a diverse range of pharmacological potentials, such as antimicrobial, antioxidant, antifeedant, enzyme inhibition, anti-inflammatory, and analgesic significance. Currently, various bioactive ingredients have been investigated for various biological activities from the genus Scutellaria in vitro and in vivo. Furthermore, these data help us to highlight its biomedical application and to isolate the responsible compounds to produce innovative medications as an alternative to synthetic drugs.

Semaphorin-3 Promotes Specific Immunotherapy Effects on Experimental Food Allergy

Sustaining higher frequency of mast cells in the allergic lesion site has been recognized. Factors causing high numbers of mast cells in the local tissues are not fully understood yet. RAS signaling plays a role in sustaining certain cell activities. This study is aimed at elucidating the role of RAS activation in the apoptosis resistance induction in mast cells and at employing semaphorin 3A to regulate RAS activities in sensitized mast cells and alleviating the allergic response in the intestine. A food allergy (FA) mouse model was developed. Mast cells were isolated from FA mouse intestinal tissues by flow cytometry. Mast cell apoptosis was assessed by staining with annexin V and propidium iodide. We found that aberrantly higher p21-activated kinase-1 (Pak1) expression in FA mast cells was associated with mast cell aggregation in the intestine. Sensitization increased Pak1 expression and apoptosis resistance in intestinal mast cells. RAS and Pak1 mutually potentiated each other in sensitized mast cells. Semaphorin 3A (sema3A) suppressed the Pak1 expression and RAS activation in mast cells. sema3A restored the apoptosis sensitivity in sensitized mast cells. Administration of sema3A potentiated allergen-specific immunotherapy in experimental FA. In conclusion, mast cells of FA mice showed higher Pak1 expression and high RAS activation status that contributed to apoptosis resistance in mast cells. Administration of sema3A restored the sensitivity to apoptosis inducers and promoted the therapeutic effects of specific immunotherapy on experimental FA.

Inhibition of U-II/UT signaling ameliorates cystitis-associated bladder hyperactivity by targeting the RhoA/Rho-kinase pathway

Urotensin II (U-II) and its receptor (UT) are involved in the pathogenesis of various diseases; however, their association with the development of cystitis has not been elucidated. The present study was designed to investigate the functional role of U-II/UT signaling in cyclophosphamide (CYP)-induced cystitis. A total of 60 female rats were randomly divided into the control and CYP-treated groups. Intraperitoneal injection of CYP successfully induced cystitis in rats of the CYP-treated group. The protein and mRNA expression levels of U-II and UT were significantly enhanced in rat bladder tissues of the CYP-treated group. Furthermore, the results of the immunofluorescence staining analysis demonstrated that CYP treatment apparently increased the expression levels of UT in the urothelium layer, detrusor smooth muscle, and bladder interstitial Cajal-like cells. The selective antagonist of UT, SB657510 (10 μm), significantly suppressed the CYP-induced increase in the spontaneous contractions of muscle strips and ameliorated the bladder hyperactivity of CYP-treated rats. Moreover, CYP treatment significantly increased the protein expression levels of Ras homolog family member (Rho) A and Rho-associated protein kinase 2 in rat bladder tissues. Following pretreatment with the Rho-kinase inhibitor Y-27632 (10 μm), the inhibitory effects of SB657510 (10 μm) on the spontaneous contractions of muscle strips were eliminated. In conclusion, the results of the present study suggested that activation of U-II/UT signaling promoted the development of cystitis-associated-bladder hyperactivity by targeting the RhoA/Rho-kinase pathway, indicating that the U-II/UT signaling could serve as a novel target for the treatment of interstitial cystitis/bladder pain syndrome.

Role and Diagnostic Performance of Host Epigenome in Respiratory Morbidity after RSV Infection: The EPIRESVi Study

Background

Respiratory syncytial virus (RSV) infection has been associated with the subsequent development of recurrent wheezing and asthma, although the mechanisms involved are still unknown. We investigate the role of epigenetics in the respiratory morbidity after infection by comparing methylation patterns from children who develop recurrent wheezing (RW-RSV), subsequent asthma (AS-RVS), and those experiencing complete recovery (CR-RSV).

Methods

Prospective, observational study of infants aged < 2 years with RSV respiratory infection admitted to hospital and followed-up after discharge for at least three years. According to their clinical course, patients were categorized into subgroups: RW-RSV (n = 36), AS-RSV (n = 9), and CR-RSV (n = 32). The DNA genome-wide methylation pattern was analyzed in whole blood samples, collected during the acute phase of the infection, using the Illumina Infinium Methylation EPIC BeadChip (850K CpG sites). Differences in methylation were determined through a linear regression model adjusted for age, gender and cell composition.

Results

Patients who developed respiratory sequelae showed a statistically significant higher proportion of NK and CD8T cells (inferred through a deconvolution approach) than those with complete recovery. We identified 5,097 significant differentially methylated positions (DMPs) when comparing RW-RSV and AS-RVS together against CR-RSV. Methylation profiles affect several genes involved in airway inflammation processes. The most significant DMPs were found to be hypomethylated in cases and therefore generally leading to overexpression of affected genes. The lead CpG position (cg24509398) falls at the gene body of EYA3 (P-value = 2.77×10^-10), a tyrosine phosphatase connected with pulmonary vascular remodeling, a key process in the asthma pathology. Logistic regression analysis resulted in a diagnostic epigenetic signature of 3-DMPs (involving genes ZNF2698, LOC102723354 and RPL15/NKIRAS1) that allows to efficiently differentiate sequelae cases from CR-RSV patients (AUC = 1.00). Enrichment pathway analysis reveals the role of the cell cycle checkpoint (FDR P-value = 4.71×10^-2), DNA damage (FDP-value = 2.53×10^-2), and DNA integrity checkpoint (FDR P-value = 2.56×10^-2) in differentiating sequelae from CR-RSV patients.

Conclusions

Epigenetic mechanisms might play a fundamental role in the long-term sequelae after RSV infection, contributing to explain the different phenotypes observed.

miR-144-3p Is a Biomarker Related to Severe Corticosteroid-Dependent Asthma

MicroRNAs are non-coding molecules that act both as regulators of the epigenetic landscape and as biomarkers for diseases, including asthma. In the era of personalized medicine, there is a need for novel disease-associated biomarkers that can help in classifying diseases into phenotypes for treatment selection. Currently, severe eosinophilic asthma is one of the most widely studied phenotypes in clinical practice, as many patients require higher and higher doses of corticosteroids, which in some cases fail to achieve the desired outcome. Such patients may only benefit from alternative drugs such as biologics, for which novel biomarkers are necessary. The objective of the study was to study the expression of miR-144-3p in order to discover its possible use as a diagnostic biomarker for severe asthma. For this purpose, miR-144-3p was evaluated in airway biopsies and serum from asthmatics and healthy individuals. mRNA was studied in asthmatic biopsies and smooth muscle cells transfected with miR-144-3p mimic. An in silico regulation of miR-144-3p was performed using miRSystem, miRDB, STRING, and ShinyGO for pathway analysis. From our experimental procedures, we found that miR-144-3p is a biomarker associated with asthma severity and corticosteroid treatment. MiR-144-3p is increased in asthmatic lungs, and its presence correlates directly with blood eosinophilia and with the expression of genes involved in asthma pathophysiology in the airways. When studied in serum, this miRNA was increased in severe asthmatics and associated with higher doses of corticosteroids, thereby making it a potential biomarker for severe asthma previously treated with higher doses of corticosteroids. Thus, we can conclude that miR-144-3p is associated with severe diseases in both the airways and serum of asthmatics, and this association is related to corticosteroid treatment.

TH17 cells and corticosteroid insensitivity in severe asthma

Asthma is classically described as having either a type 2 (T2) eosinophilic phenotype or a non-T2 neutrophilic phenotype. T2 asthma usually responds to classical bronchodilation therapy and corticosteroid treatment. Non-T2 neutrophilic asthma is often more severe. Patients with non-T2 asthma or late-onset T2 asthma show poor response to the currently available anti-inflammatory therapies. These therapeutic failures result in increased morbidity and cost associated with asthma and pose a major health care problem. Recent evidence suggests that some non-T2 asthma is associated with elevated T_H17 cell immune responses. T_H17 cells producing Il-17A and IL-17F are involved in the neutrophilic inflammation and airway remodeling processes in severe asthma and have been suggested to contribute to the development of subsets of corticosteroid-insensitive asthma. This review explores the pathologic role of T_H17 cells in corticosteroid insensitivity of severe asthma and potential targets to treat this endotype of asthma.

Topical therapy with negative allosteric modulators of the calcium-sensing receptor (calcilytics) for the management of asthma: the beginning of a new era?

In this review article we present the evidence to date supporting the role of the calcium-sensing receptor (CaSR) as a key, pluripotential molecular trigger for asthma and speculate on the likely benefits of topical therapy of asthma with negative allosteric modulators of the CaSR: calcilytics.

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.

Type II alveolar epithelial cell-specific loss of RhoA exacerbates allergic airway inflammation through SLC26A4

The small GTPase RhoA and its downstream effectors are critical regulators in the pathophysiological processes of asthma. The underlying mechanism, however, remains undetermined. Here, we generated an asthma mouse model with RhoA–conditional KO mice (Sftpc-cre;RhoA^fl/fl) in type II alveolar epithelial cells (AT2) and demonstrated that AT2 cell–specific deletion of RhoA leads to exacerbation of allergen-induced airway hyperresponsiveness and airway inflammation with elevated Th2 cytokines in bronchoalveolar lavage fluid (BALF). Notably, Sftpc-cre;RhoA^fl/fl mice showed a significant reduction in Tgf-β1 levels in BALF and lung tissues, and administration of recombinant Tgf-β1 to the mice rescued Tgf-β1 and alleviated the increased allergic airway inflammation observed in Sftpc-cre;RhoA^fl/fl mice. Using RNA sequencing technology, we identified Slc26a4 (pendrin), a transmembrane anion exchange, as the most upregulated gene in RhoA-deficient AT2 cells. The upregulation of SLC26A4 was further confirmed in AT2 cells of asthmatic patients and mouse models and in human airway epithelial cells expressing dominant-negative RHOA (RHOA-N19). SLA26A4 was also elevated in serum from asthmatic patients and negatively associated with the percentage of forced expiratory volume in 1 second (FEV₁%). Furthermore, SLC26A4 inhibition promoted epithelial TGF-β1 release and attenuated allergic airway inflammation. Our study reveals a RhoA/SLC26A4 axis in AT2 cells that functions as a protective mechanism against allergic airway inflammation.

The Rho kinase (ROCK) inhibitor Y-27632 reduces the β2-adrenoceptor density but enhance cAMP formation in primary equine bronchial epithelial cells

The present study addresses the effect of the Rho-kinase (ROCK) inhibitor Y-27632 on the β₂-adrenoceptor density and β-agonist-stimulated intracellular second messenger cAMP formation in primary equine bronchial epithelial cells (EBEC). Y-27632 significantly decreased the β₂-adrenoceptor number (B_max) without markedly affecting the receptor affinity (dissociation constant, K_D) to the radioligand [¹²⁵I]-iodocyanopindolol (ICYP). In contrast, Y-27632 augmented the β-agonist-stimulated intracellular cAMP production. Herein, Y-27632 markedly increased the maximal cAMP responses (E_max) (isoproterenol > epinephrine > norepinephrine) but did not shift the β-agonist concentration-effect curves to the left. The β₂-selective antagonist ICI 118.551 and the β_1/β₂-antagonsit propranolol but not the β₁-selctive antagonist CGP 20712A reversed the isoproterenol-induced cAMP formation equally in Y-27632-treated and control EBEC, suggesting the effect was merely related to the β₂-subtype. These results show that Y-27632 differentially regulates the receptor density and function. Thus, these findings provide the first evidence that the functional interaction of the β₂-adrenoceptor and Rho-kinase (ROCK) signaling pathways decreases the receptor expression but enhances receptor downstream cAMP formation. This differential regulation of the receptor density and function by Y-27632 should be further reconsidered with regard to the beneficial effect of the drug in asthma therapy.

Several Fusion Genes Identified in a Spermatic Cord Leiomyoma With Rearrangements of Chromosome Arms 3p and 21q

BACKGROUND/AIM

Benign smooth-muscle tumors, leiomyomas, occur in nearly every organ but are most common in the uterus. Whereas much is known about the genetics of uterine leiomyomas, little genetic information exists about leiomyomas of other organs. Here, we report and discuss the genetic findings in a para-testicular leiomyoma.

MATERIALS AND METHODS

Cytogenetic, array comparative genomic hybridization (aCGH) RNA sequencing, reverse-transcription polymerase chain reaction (RT- PCR), and Sanger sequencing analyses were performed on a leiomyoma of the spermatic cord removed from a 61-year-old man.

RESULTS

The karyotype was 48~50,XY,add(3) (p21),+4,+7,+8,+9,add(21)(q22)[cp9]/46,XY[2]. aCGH confirmed the trisomies and also detected multiple gains and losses from 3p and 21q. RNA sequencing detected the chimeras ARHGEF3-CACNA2D2, TRAK1-TIMP4, ITPR1- DT-NR2C2, CLASP2-IL17RD, ZNF621-LARS2, CNTN4- RHOA, and NR2C2-CFAP410. All chimeras were confirmed by RT-PCR and Sanger sequencing.

CONCLUSION

Our data, together with those previously published, indicate that a group of leiomyomas may be cytogenetically characterized by aberrations of 3p and the formation of fusion genes.

Review - Nutraceuticals Can Target Asthmatic Bronchoconstriction: NADPH Oxidase-Dependent Oxidative Stress, RhoA and Calcium Dynamics

Activation of various isoforms of NADPH oxidase contributes to the pathogenesis of asthma at multiple levels: promoting hypercontractility, hypertrophy, and proliferation of airway smooth muscle; enabling lung influx of eosinophils via VCAM-1; and mediating allergen-induced mast cell activation. Free bilirubin, which functions physiologically within cells as a feedback inhibitor of NADPH oxidase complexes, has been shown to have a favorable impact on each of these phases of asthma pathogenesis. The spirulina chromophore phycocyanobilin (PhyCB), a homolog of bilirubin’s precursor biliverdin, can mimic the inhibitory impact of biliverdin/bilirubin on NADPH oxidase activity, and spirulina’s versatile and profound anti-inflammatory activity in rodent studies suggests that PhyCB may have potential as a clinical inhibitor of NADPH oxidase. Hence, spirulina or PhyCB-enriched spirulina extracts merit clinical evaluation in asthma. Promoting biosynthesis of glutathione and increasing the expression and activity of various antioxidant enzymes – as by supplementing with N-acetylcysteine, Phase 2 inducers (eg, lipoic acid), selenium, and zinc – may also blunt the contribution of oxidative stress to asthma pathogenesis. Nitric oxide (NO) and hydrogen sulfide (H₂S) work in various ways to oppose pathogenic mechanisms in asthma; supplemental citrulline and high-dose folate may aid NO synthesis, high-dose biotin may mimic and possibly potentiate NO’s activating impact on soluble guanylate cyclase, and NAC and taurine may boost H₂S synthesis. The amino acid glycine has a hyperpolarizing effect on airway smooth muscle that is bronchodilatory. Insuring optimal intracellular levels of magnesium may modestly blunt the stimulatory impact of intracellular free calcium on bronchoconstriction. Nutraceutical regimens or functional foods incorporating at least several of these agents may have utility as nutraceutical adjuvants to standard clinical management of asthma.

Scutellaria baicalensis and Their Natural Flavone Compounds as Potential Medicinal Drugs for the Treatment of Nicotine-Induced Non-Small-Cell Lung Cancer and Asthma

Flavonoids as the largest group of natural phytochemical compounds have received significant attention, as demonstrated by clinical trials, due to their chemotherapeutic and/or pharmacological effects against non-small-cell lung cancer (NSCLC) and asthma. Scutellaria baicalensis (S. baicalensis), known as one of the most popular medicinal plants and used in several countries, contains natural active flavone constituents, with the major compounds of the roots being baicalein, baicalin, wogonin, wogonoside and oroxylin A. S. baicalensis and their compounds are proven to have inhibitory effects on NSCLC cells when used at different concentrations. However, the exact mechanisms by which these compounds exert their therapeutic effects against asthma remain unexplored. Indeed, the mechanisms by which S. baicalensis and its flavone compounds exert a protective effect against nicotine-induced NSCLC and asthma are not yet fully understood. Therefore, this review explores the mechanisms involved in the therapeutic potential of flavone-rich extracts from S. baicalensis in nicotine-induced NSCLC and asthma.

Airway macrophage-intrinsic TGF-β1 regulates pulmonary immunity during early-life allergen exposure

BACKGROUND

Early life represents a major risk window for asthma development. However, the mechanisms controlling the threshold for establishment of allergic airway inflammation in early life are incompletely understood. Airway macrophages (AMs) regulate pulmonary allergic responses and undergo TGF-β-dependent postnatal development, but the role of AM maturation factors such as TGF-β in controlling the threshold for pathogenic immune responses to inhaled allergens remains unclear.

OBJECTIVE

Our aim was to test the hypothesis that AM-derived TGF-β1 regulates pathogenic immunity to inhaled allergen in early life.

METHODS

Conditional knockout (Tgfb1ΔCD11c) mice, with TGF-β1 deficiency in AMs and other CD11c+ cells, were analyzed throughout early life and following neonatal house dust mite (HDM) inhalation. The roles of specific chemokine receptors were determined by using in vivo blocking antibodies.

RESULTS

AM-intrinsic TGF-β1 was redundant for initial population of the neonatal lung with AMs, but AMs from Tgfb1ΔCD11c mice failed to adopt a mature homeostatic AM phenotype in the first weeks of life. Evidence of constitutive TGF-β1 signaling was also observed in pediatric human AMs. TGF-β1-deficient AMs expressed enhanced levels of monocyte-attractant chemokines, and accordingly, Tgfb1ΔCD11c mice exposed to HDM throughout early life accumulated CCR2-dependent inflammatory CD11c+ mononuclear phagocytes into the airway niche that expressed the proallergic chemokine CCL8. Tgfb1ΔCD11c mice displayed augmented TH2, group 2 innate lymphoid cell, and airway remodeling responses to HDM, which were ameliorated by blockade of the CCL8 receptor CCR8.

CONCLUSION

Our results highlight a causal relationship between AM maturity, chemokines, and pathogenic immunity to environmental stimuli in early life and identify TGF-β1 as a key regulator of this.

Rho/ROCK-MYOCD in regulating airway smooth muscle growth and remodeling

Abnormal airway remodeling is a common pathological change seen in chronic respiratory diseases. Altered proliferation and differentiation of airway smooth muscle cells (ASMCs) are the major components of airway remodeling, and the resultant structural abnormalities are difficult to restore. Understanding of airway smooth muscle regulation is urgently needed to identify potential intervention targets. MYOCD (or myocardin) and myocardin-related transcription factors (MRTFs) are key cotranscription factors in muscle growth, which have not been extensively investigated in airway smooth muscle cells. In addition, the RhoA/ROCK signaling pathway is known to play an important role in airway remodeling partly through regulating the proliferation and differentiation of ASMCs, which may be connected with MYOCD/MRTF cotranscription factors [Kumawat et al. (Am J Physiol Lung Cell Mol Physiol 311: L529-L537, 2016); Lagna et al. (J Biol Chem 282: 37244-37255, 2007)]. This review focuses on this newly recognized and potentially important RhoA/ROCK-MYOCD/MRTFs pathway in controlling airway smooth muscle growth and remodeling.

Benzo(a)pyrene Enhanced Dermatophagoides Group 1 (Der f 1)-Induced TGFβ1 Signaling Activation Through the Aryl Hydrocarbon Receptor-RhoA Axis in Asthma

We have previously demonstrated that benzo(a)pyrene (BaP) co-exposure with dermatophagoides group 1 allergen (Der f 1) can potentiate Der f 1-induced airway inflammation. The underlying mechanism, however, remains undetermined. Here we investigated the molecular mechanisms underlying the potentiation of BaP exposure on Der f 1-induced airway inflammation in asthma. We found that BaP co-exposure potentiated Der f 1-induced TGFβ1 secretion and signaling activation in human bronchial epithelial cells (HBECs) and the airways of asthma mouse model. Moreover, BaP exposure alone or co-exposure with Der f 1-induced aryl hydrocarbon receptor (AhR) activity was determined by using an AhR-dioxin-responsive element reporter plasmid. The BaP and Der f 1 co-exposure-induced TGFβ1 expression and signaling activation were attenuated by either AhR antagonist CH223191 or AhR knockdown in HBECs. Furthermore, AhR knockdown led to the reduction of BaP and Der f 1 co-exposure-induced active RhoA. Inhibition of RhoA signaling with fasudil, a RhoA/ROCK inhibitor, suppressed BaP and Der f 1 co-exposure-induced TGFβ1 expression and signaling activation. This was further confirmed in HBECs expressing constitutively active RhoA (RhoA-L63) or dominant-negative RhoA (RhoA-N19). Luciferase reporter assays showed prominently increased promoter activities for the AhR binding sites in the promoter region of RhoA. Inhibition of RhoA suppressed BaP and Der f 1 co-exposure-induced airway hyper-responsiveness, Th2-associated airway inflammation, and TGFβ1 signaling activation in asthma. Our studies reveal a previously unidentified functional axis of AhR–RhoA in regulating TGFβ1 expression and signaling activation, representing a potential therapeutic target for allergic asthma.

RGS proteins, GRKs, and beta-arrestins modulate G protein-mediated signaling pathways in asthma

Asthma is a highly prevalent disorder characterized by chronic lung inflammation and reversible airways obstruction. Pathophysiological features of asthma include episodic and reversible airway narrowing due to increased bronchial smooth muscle shortening in response to external and host-derived mediators, excessive mucus secretion into the airway lumen, and airway remodeling. The aberrant airway smooth muscle (ASM) phenotype observed in asthma manifests as increased sensitivity to contractile mediators (EC₅₀) and an increase in the magnitude of contraction (E_max); collectively these attributes have been termed "airways hyper-responsiveness" (AHR). This defining feature of asthma can be promoted by environmental factors including airborne allergens, viruses, and air pollution and other irritants. AHR reduces airway caliber and obstructs airflow, evoking clinical symptoms such as cough, wheezing and shortness of breath. G-protein-coupled receptors (GPCRs) have a central function in asthma through their impact on ASM and airway inflammation. Many but not all treatments for asthma target GPCRs mediating ASM contraction or relaxation. Here we discuss the roles of specific GPCRs, G proteins, and their associated signaling pathways, in asthma, with an emphasis on endogenous mechanisms of GPCR regulation of ASM tone and lung inflammation including regulators of G-protein signaling (RGS) proteins, G-protein coupled receptor kinases (GRKs), and β-arrestin.