The Rho kinases: critical mediators of multiple profibrotic processes and rational targets for new therapies for pulmonary fibrosis

The current landscape of antifibrotic therapy across different organs: A systematic approach

Fibrosis is a common pathological process that can affect virtually all the organs, but there are hardly any effective therapeutic options. This has led to an intense search for antifibrotic therapies over the last decades, with a great number of clinical assays currently underway. We have systematically reviewed all current and recently finished clinical trials involved in the development of new antifibrotic drugs, and the preclinical studies analyzing the relevance of each of these pharmacological strategies in fibrotic processes affecting tissues beyond those being clinically studied. We analyze and discuss this information with the aim of determining the most promising options and the feasibility of extending their therapeutic value as antifibrotic agents to other fibrotic conditions.

Mechanotransduction and the extracellular matrix: Key drivers of lung pathologies and drug responsiveness

The lung is a biomechanically active organ, with multiscale mechanical forces impacting the organ, tissue and cellular responses within this microenvironment. In chronic lung diseases, such as chronic obstructive pulmonary disease, pulmonary fibrosis and others, the structure of the lung is drastically altered impeding gas exchange. These changes are, in part, reflected in alterations in the composition, amount and organization of the extracellular matrix within the different lung compartments. The transmission of mechanical forces within lung tissue are broadcast by this complex mix of extracellular matrix components, in particular the collagens, elastin and proteoglycans and the crosslinking of these components. At both a macro and a micro level, the mechanical properties of the microenvironment have a key regulatory role in ascertaining cellular responses and the function of the lung. Cells adhere to, and receive signals from, the extracellular matrix through a number of different surface receptors and complexes which are important for mechanotransduction. This review summarizes the multiscale mechanics in the lung and how the mechanical environment changes in lung disease and aging. We then examine the role of mechanotransduction in driving cell signaling events in lung diseases and finish with a future perspective of the need to consider how such forces may impact pharmacological responsiveness in lung diseases.

Targeting ROCK2 improves macromolecular permeability in a 3D fibrotic pancreatic cancer microenvironment model

Pancreatic cancer is characterized by a densely fibrotic stroma. The fibrotic stroma hinders the intratumoral penetration of nanomedicine and diminishes therapeutic efficacy. Fibrosis is characterized by an abnormal organization of extracellular matrix (ECM) components, namely the abnormal deposition and/or orientation of collagen and fibronectin. Abnormal ECM organization is chiefly driven by pathological signaling in pancreatic stellate cells (PSCs), the main cell type involved in fibrogenesis. However, whether targeting signaling pathways involved in abnormal ECM organization improves the intratumoral penetration of nanomedicines is unknown. Here, we show that targeting transforming growth factor-β (TGFβ)/Rho-associated kinase (ROCK) 1/2 signaling in PSCs normalizes ECM organization and concomitantly improves macromolecular permeability of the fibrotic stroma. Using a 3-dimensional cell culture model of the fibrotic pancreatic cancer microenvironment, we found that pharmacological inhibition of TGFβ or ROCK1/2 improves the permeation of various macromolecules. By using an isoform-specific pharmacological inhibitor and siRNAs, we show that targeting ROCK2, but not ROCK1, alone is sufficient to normalize ECM organization and improve macromolecular permeability. Moreover, we found that ROCK2 inhibition/knockdown attenuates Yes-associated protein (YAP) nuclear localization in fibroblasts co-cultured with pancreatic cancer cells in 3D. Finally, pharmacological inhibition or siRNA-mediated knockdown of YAP normalized ECM organization and improved macromolecular permeability. Our results together suggest that the TGFβ/ROCK2/YAP signaling axis may be therapeutically targeted to normalize ECM organization and improve macromolecular permeability to augment therapeutic efficacy of nanomedicines in pancreatic cancer.

ROCK and the actomyosin network control biomineral growth and morphology during sea urchin skeletogenesis

Biomineralization had apparently evolved independently in different phyla, using distinct minerals, organic scaffolds, and gene regulatory networks (GRNs). However, diverse eukaryotes from unicellular organisms, through echinoderms to vertebrates, use the actomyosin network during biomineralization. Specifically, the actomyosin remodeling protein, Rho-associated coiled-coil kinase (ROCK) regulates cell differentiation and gene expression in vertebrates' biomineralizing cells, yet, little is known on ROCK's role in invertebrates' biomineralization. Here, we reveal that ROCK controls the formation, growth, and morphology of the calcite spicules in the sea urchin larva. ROCK expression is elevated in the sea urchin skeletogenic cells downstream of the Vascular Endothelial Growth Factor (VEGF) signaling. ROCK inhibition leads to skeletal loss and disrupts skeletogenic gene expression. ROCK inhibition after spicule formation reduces the spicule elongation rate and induces ectopic spicule branching. Similar skeletogenic phenotypes are observed when ROCK is inhibited in a skeletogenic cell culture, indicating that these phenotypes are due to ROCK activity specifically in the skeletogenic cells. Reduced skeletal growth and enhanced branching are also observed under direct perturbations of the actomyosin network. We propose that ROCK and the actomyosin machinery were employed independently, downstream of distinct GRNs, to regulate biomineral growth and morphology in Eukaryotes.

Exploring therapeutic targets for molecular therapy of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis is a chronic and progressive interstitial lung disease with a poor prognosis. Idiopathic pulmonary fibrosis is characterized by repeated alveolar epithelial damage leading to abnormal repair. The intercellular microenvironment is disturbed, leading to continuous activation of fibroblasts and myofibroblasts, deposition of extracellular matrix, and ultimately fibrosis. Moreover, pulmonary fibrosis was also found as a COVID-19 complication. Currently, two drugs, pirfenidone and nintedanib, are approved for clinical therapy worldwide. However, they can merely slow the disease's progression rather than rescue it. These two drugs have other limitations, such as lack of efficacy, adverse effects, and poor pharmacokinetics. Consequently, a growing number of molecular therapies have been actively developed. Treatment options for IPF are becoming increasingly available. This article reviews the research platform, including cell and animal models involved in molecular therapy studies of idiopathic pulmonary fibrosis as well as the promising therapeutic targets and their development progress during clinical trials. The former includes patient case/control studies, cell models, and animal models. The latter includes transforming growth factor-beta, vascular endothelial growth factor, platelet-derived growth factor, fibroblast growth factor, lysophosphatidic acid, interleukin-13, Rho-associated coiled-coil forming protein kinase family, and Janus kinases/signal transducers and activators of transcription pathway. We mainly focused on the therapeutic targets that have not only entered clinical trials but were publicly published with their clinical outcomes. Moreover, this work provides an outlook on some promising targets for further validation of their possibilities to cure the disease.

Recent Advancement in Elimination Strategies and Potential Rejuvenation Targets of Senescence

Cellular senescence is a state of exiting the cell cycle, resisting apoptosis, and changing phenotype. Senescent cells (SCs) can be identified by large, distorted morphology and irreversible inability to replicate. In early development, senescence has beneficial roles like tissue patterning and wound healing, where SCs are cleared by the immune system. However, there is a steep rise in SC number as organisms age. The issue with SC accumulation stems from the loss of cellular function, alterations of the microenvironment, and secretions of pro-inflammatory molecules, consisting of cytokines, chemokines, matrix metalloproteinases (MMPs), interleukins, and extracellular matrix (ECM)-associated molecules. This secreted cocktail is referred to as the senescence-associated secretory phenotype (SASP), a hallmark of cellular senescence. The SASP promotes inflammation and displays a bystander effect where paracrine signaling turns proliferating cells into senescent states. To alleviate age-associated diseases, researchers have developed novel methods and techniques to selectively eliminate SCs in aged individuals. Although studies demonstrated that selectively killing SCs improves age-related disorders, there are drawbacks to SC removal. Considering favorable aspects of senescence in the body, this paper reviews recent advancements in elimination strategies and potential rejuvenation targets of senescence to bring researchers in the field up to date.

A novel mechanoeffector role of fibroblast S100A4 in myofibroblast transdifferentiation and fibrosis

Fibroblast to myofibroblast transdifferentiation mediates numerous fibrotic disorders, such as idiopathic pulmonary fibrosis (IPF). We have previously demonstrated that non-muscle myosin II (NMII) is activated in response to fibrotic lung extracellular matrix, thereby mediating myofibroblast transdifferentiation. NMII-A is known to interact with the calcium-binding protein S100A4, but the mechanism by which S100A4 regulates fibrotic disorders is unclear. In this study, we show that fibroblast S100A4 is a calcium-dependent, mechanoeffector protein that is uniquely sensitive to pathophysiologic-range lung stiffness (8-25 kPa) and thereby mediates myofibroblast transdifferentiation. Re-expression of endogenous fibroblast S100A4 rescues the myofibroblastic phenotype in S100A4 KO fibroblasts. Analysis of NMII-A/actin dynamics reveals that S100A4 mediates the unraveling and redistribution of peripheral actomyosin to a central location, resulting in a contractile myofibroblast. Furthermore, S100A4 loss protects against murine in vivo pulmonary fibrosis, and S100A4 expression is dysregulated in IPF. Our data reveal a novel mechanosensor/effector role for endogenous fibroblast S100A4 in inducing cytoskeletal redistribution in fibrotic disorders such as IPF.

SLIT3 promotes cardiac fibrosis and differentiation of cardiac fibroblasts by RhoA/ROCK1 signaling pathway

Objectives

Slit guidance ligand 3 (SLIT3) has been identified as a potential therapeutic regulator against fibroblast activity and fibrillary collagen production in an autocrine manner. However, this research aims to investigate the potential role of SLIT3 in cardiac fibrosis and fibroblast differentiation and its underlying mechanism.

Materials and Methods

C57BL/6 mice (male, 8-10 weeks, n=47) were subcutaneously infused with Ang II (2.0 mg/kg/day) for 4 weeks. One to two-day-old Sprague-Dawley (SD) rats were anesthetized by intraperitoneal injection of 1% pentobarbital sodium (60 mg/kg) and ketamine (50 mg/kg) and the cardiac fibroblast was isolated aseptically. The mRNA and protein expression were analyzed using RT-qPCR and Western blotting.

Results

The SLIT3 expression level was increased in Ang II-induced mice models and cardiac fibroblasts. SLIT3 significantly increased migrated cells and α-smooth muscle actin (α-SMA) expression in cardiac fibroblasts. Ang II-induced increases in mRNA expression of collagen I (COL1A1), and collagen III (COL3A1) was attenuated by SLIT3 inhibition. SLIT3 knockdown attenuated the Ang II-induced increase in mRNA expression of ACTA2 (α-SMA), Fibronectin, and CTGF. SLIT3 suppression potentially reduced DHE expression and decreased malondialdehyde (MDA) content, and the superoxide dismutase (SOD) and catalase (CAT) levels were significantly increased in cardiac fibroblasts. Additionally, SLIT3 inhibition markedly decreased RhoA and ROCK1 protein expression, whereas ROCK inhibitor Y-27632 (10 μM) markedly attenuated the migration of cardiac fibroblasts stimulated by Ang II and SLIT3.

Conclusion

The results speculate that SLIT3 could significantly regulate cardiac fibrosis and fibroblast differentiation via the RhoA/ROCK1 signaling pathway.

Tuftelin1 drives experimental pulmonary fibrosis progression by facilitating stress fiber assembly

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease (ILD) with unknown etiology, characterized by sustained damage repair of epithelial cells and abnormal activation of fibroblasts, the underlying mechanism of the disease remains elusive.

METHODS

To evaluate the role of Tuftelin1 (TUFT1) in IPF and elucidate its molecular mechanism. We investigated the level of TUFT1 in the IPF and bleomycin-induced mouse models and explored the influence of TUFT1 deficiency on pulmonary fibrosis. Additionally, we explored the effect of TUFT1 on the cytoskeleton and illustrated the relationship between stress fiber and pulmonary fibrosis.

RESULTS

Our results demonstrated a significant upregulation of TUFT1 in IPF and the bleomycin (BLM)-induced fibrosis model. Disruption of TUFT1 exerted inhibitory effects on pulmonary fibrosis in both in vivo and in vitro. TUFT1 facilitated the assembly of microfilaments in A549 and MRC-5 cells, with a pronounced association between TUFT1 and Neuronal Wiskott-Aldrich syndrome protein (N-WASP) observed during microfilament formation. TUFT1 can promote the phosphorylation of tyrosine residue 256 (Y256) of the N-WASP (pY256N-WASP). Furthermore, TUFT1 promoted transforming growth factor-β1 (TGF-β1) induced fibroblast activation by increasing nuclear translocation of pY256N-WASP in fibroblasts, while wiskostatin (Wis), an N-WASP inhibitor, suppressed these processes.

CONCLUSIONS

Our findings suggested that TUFT1 plays a critical role in pulmonary fibrosis via its influence on stress fiber, and blockade of TUFT1 effectively reduces pro-fibrotic phenotypes. Pharmacological targeting of the TUFT1-N-WASP axis may represent a promising therapeutic approach for pulmonary fibrosis.

Understanding and treatment of cutaneous graft-versus-host-disease

The skin is the outermost mechanical barrier where dynamic immune reactions take place and is the most commonly affected site in both acute and chronic graft-versus-host disease (GVHD). If not properly treated, pain and pruritis resulting from cutaneous GVHD can increase the risk of secondary infection due to erosions, ulcerations, and damage of underlying tissues. Furthermore, resulting disfiguration can cause distress and significantly impact patients' quality of life. Thus, a deeper understanding of skin-specific findings of GVHD is needed. This review will highlight some promising results of recent pre-clinical studies on the pathophysiology of skin GVHD and summarize the diagnostic and staging/grading procedures according to the clinical manifestations of skin GVHD. In addition, we will summarize outcomes of various GVHD treatments, including skin-specific response rates.

Pulmonary fibrosis: Emerging diagnostic and therapeutic strategies

Fibrosis is the concluding pathological outcome and major cause of morbidity and mortality in a number of common chronic inflammatory, immune-mediated and metabolic diseases. The progressive deposition of a collagen-rich extracellular matrix (ECM) represents the cornerstone of the fibrotic response and culminates in organ failure and premature death. Idiopathic pulmonary fibrosis (IPF) represents the most rapidly progressive and lethal of all fibrotic diseases with a dismal median survival of 3.5 years from diagnosis. Although the approval of the antifibrotic agents, pirfenidone and nintedanib, for the treatment of IPF signalled a watershed moment for the development of anti-fibrotic therapeutics, these agents slow but do not halt disease progression or improve quality of life. There therefore remains a pressing need for the development of effective therapeutic strategies. In this article, we review emerging therapeutic strategies for IPF as well as the pre-clinical and translational approaches that will underpin a greater understanding of the key pathomechanisms involved in order to transform the way we diagnose and treat pulmonary fibrosis.

Selectivity matters: selective ROCK2 inhibitor ameliorates established liver fibrosis via targeting inflammation, fibrosis, and metabolism

The pathogenesis of hepatic fibrosis is driven by dysregulated metabolism precipitated by chronic inflammation. Rho-associated coiled-coil-containing protein kinases (ROCKs) have been implicated in these processes, however the ability of selective ROCK2 inhibition to target simultaneously profibrotic, pro-inflammatory and metabolic pathways remains undocumented. Here we show that therapeutic administration of GV101, a selective ROCK2 inhibitor with more than 1000-fold selectivity over ROCK1, attenuates established liver fibrosis induced by thioacetamide (TAA) in combination with high-fat diet in mice. GV101 treatment significantly reduces collagen levels in liver, associated with downregulation of pCofilin, pSTAT3, pAkt, while pSTAT5 and pAMPK levels are increased in tissues of treated mice. In vitro, GV101 inhibits profibrogenic markers expression in fibroblasts, adipogenesis in primary adipocytes and TLR-induced cytokine secretion in innate immune cells via targeting of Akt-mTOR-S6K signaling axis, further uncovering the ROCK2-specific complex mechanism of action and therapeutic potential of highly selective ROCK2 inhibitors in liver fibrosis.

Emerging opportunities to treat idiopathic pulmonary fibrosis: Design, discovery, and optimizations of small-molecule drugs targeting fibrogenic pathways

Idiopathic pulmonary fibrosis (IPF) is the most common fibrotic form of idiopathic diffuse lung disease. Due to limited treatment options, IPF patients suffer from poor survival. About ten years ago, Pirfenidone (Shionogi, 2008; InterMune, 2011) and Nintedanib (Boehringer Ingelheim, 2014) were approved, greatly changing the direction of IPF drug design. However, limited efficacy and side effects indicate that neither can reverse the process of IPF. With insights into the occurrence of IPF, novel targets and agents have been proposed, which have fundamentally changed the treatment of IPF. With the next-generation agents, targeting pro-fibrotic pathways in the epithelial-injury model offers a promising approach. Besides, several next-generation IPF drugs have entered phase II/III clinical trials with encouraging results. Due to the rising IPF treatment requirements, there is an urgent need to completely summarize the mechanisms, targets, problems, and drug design strategies over the past ten years. In this review, we summarize known mechanisms, target types, drug design, and novel technologies of IPF drug discovery, aiming to provide insights into the future development and clinical application of next-generation IPF drugs.

The potential role of miRNA in regulating macrophage polarization

Macrophage polarization is a dynamic process determining the outcome of various physiological and pathological situations through inducing pro-inflammatory responses or resolving inflammation via exerting anti-inflammatory effects. The miRNAs are epigenetic regulators of different biologic pathways that target transcription factors and signaling molecules to promote macrophage phenotype transition and regulate immune responses. Modulating the macrophage activation, differentiation, and polarization by miRNAs is crucial for immune responses in response to microenvironmental signals and under various physiological and pathological conditions. In term of clinical significance, regulating macrophage polarization via miRNAs could be utilized for inflammation control. Also, understanding the role of miRNAs in macrophage polarization can provide insights into diagnostic strategies associated with dysregulated miRNAs and for developing macrophage-centered therapeutic methods. In this case, targeting miRNAs to further regulate of macrophage polarization may become an efficient strategy for treating immune-associated disorders. The current review investigated and categorized various miRNAs directly or indirectly involved in macrophage polarization by targeting different transcription factors and signaling pathways. In addition, prospects for regulating macrophage polarization via miRNA as a therapeutic choice that could be implicated in various pathological conditions, including cancer or inflammation-mediated injuries, were discussed.

FDCA Attenuates Neuroinflammation and Brain Injury after Cerebral Ischemic Stroke

Ischemic stroke is a deleterious cerebrovascular disease with few therapeutic options, and its functional recovery is highly associated with the integrity of the blood-brain barrier and neuroinflammation. The Rho-associated coiled-coil containing protein kinase (ROCK) inhibitor fasudil (F) and the pyruvate dehydrogenase kinase (PDK) inhibitor dichloroacetate (DCA) have been demonstrated to exhibit neuroprotection in a series of neurological disorders. Hence, we synthesized and biologically examined the new salt fasudil dichloroacetate (FDCA) and validated that FDCA was eligible for attenuating ischemic volume and neurological deficits in the rat transient middle cerebral artery occlusion (tMCAO) model. Additionally, FDCA exerted superior effects than fasudil and dichloroacetate alone or in combination in reducing cerebral ischemic injury. Particularly, FDCA could maintain the blood-brain barrier (BBB) integrity by inhibiting matrix metalloproteinase 9 (MMP-9) protein expression and the degradation of zonula occludens (ZO-1) and Occludin protein. Meanwhile, FDCA could mitigate the neuroinflammation induced by microglia. The in vivo and in vitro experiments further demonstrated that FDCA disrupted the phosphorylations of myosin phosphatase target subunit 1 (MYPT1), mitogen-activated protein kinase (MAPK) cascade, including p38 and c-Jun N-terminal kinase (JNK), and pyruvate dehydrogenase (PDH) and limited excessive lactic acid metabolites, resulting in inhibition of BBB disruption and neuroinflammation. In addition, FDCA potently mitigated inflammatory response in human monocytes isolated from ischemic stroke patients, which provides the possibilities of a clinical translation perspective. Overall, these findings provided a therapeutic potential for FDCA as a candidate agent for ischemic stroke and other neurological diseases associated with BBB disruption and neuroinflammation.

Beyond epithelial damage: vascular and endothelial contributions to idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive scarring disease of the lung with poor survival. The incidence and mortality of IPF are rising, but treatment remains limited. Currently, two drugs can slow the scarring process but often at the expense of intolerable side effects, and without substantially changing overall survival. A better understanding of mechanisms underlying IPF is likely to lead to improved therapies. The current paradigm proposes that repetitive alveolar epithelial injury from noxious stimuli in a genetically primed individual is followed by abnormal wound healing, including aberrant activity of extracellular matrix-secreting cells, with resultant tissue fibrosis and parenchymal damage. However, this may underplay the importance of the vascular contribution to fibrogenesis. The lungs receive 100% of the cardiac output, and vascular abnormalities in IPF include (a) heterogeneous vessel formation throughout fibrotic lung, including the development of abnormal dilated vessels and anastomoses; (b) abnormal spatially distributed populations of endothelial cells (ECs); (c) dysregulation of endothelial protective pathways such as prostacyclin signaling; and (d) an increased frequency of common vascular and metabolic comorbidities. Here, we propose that vascular and EC abnormalities are both causal and consequential in the pathobiology of IPF and that fuller evaluation of dysregulated pathways may lead to effective therapies and a cure for this devastating disease.

Idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive devastating lung disease with substantial morbidity. It is associated with cough, dyspnea and impaired quality of life. If left untreated, IPF has a median survival of 3 years. IPF affects ∼3 million people worldwide, with increasing incidence in older patients. The current concept of pathogenesis is that pulmonary fibrosis results from repetitive injury to the lung epithelium, with fibroblast accumulation, myofibroblast activation, and deposition of matrix. These injuries, in combination with innate and adaptive immune responses, dysregulated wound repair and fibroblast dysfunction, lead to recurring tissue remodeling and self-perpetuating fibrosis as seen in IPF. The diagnostic approach includes the exclusion of other interstitial lung diseases or underlying conditions and depends on a multidisciplinary team-based discussion combining radiological and clinical features and well as in some cases histology. In the last decade, considerable progress has been made in the understanding of IPF clinical management, with the availability of two drugs, pirfenidone and nintedanib, that decrease pulmonary lung function decline. However, current IPF therapies only slow disease progression and prognosis remains poor. Fortunately, there are multiple clinical trials ongoing with potential new therapies targeting different disease pathways. This review provides an overview of IPF epidemiology, current insights in pathophysiology, diagnostic and therapeutic management approaches. Finally, a detailed description of current and evolving therapeutic approaches is also provided.

NFATc3 Promotes Pulmonary Inflammation and Fibrosis by Regulating Production of CCL2 and CXCL2 in Macrophages

Idiopathic pulmonary fibrosis (IPF) is a progressive and highly lethal inflammatory interstitial lung disease characterized by aberrant extracellular matrix deposition. Macrophage activation by cytokines released from repetitively injured alveolar epithelial cells regulates the inflammatory response, tissue remodeling, and fibrosis throughout various phases of IPF. Our previous studies demonstrate that nuclear factor of activated T cells cytoplasmic member 3 (NFATc3) regulates a wide array of macrophage genes during acute lung injury pathogenesis. However, the role of NFATc3 in IPF pathophysiology has not been previously reported. In the current study, we demonstrate that expression of NFATc3 is elevated in lung tissues and pulmonary macrophages in mice subjected to bleomycin (BLM)-induced pulmonary fibrosis and IPF patients. Remarkably, NFATc3 deficiency (NFATc3+/-) was protective in bleomycin (BLM)-induced lung injury and fibrosis. Adoptive transfer of NFATc3+/+ macrophages to NFATc3+/- mice restored susceptibility to BLM-induced pulmonary fibrosis. Furthermore, in vitro treatment with IL-33 or conditioned medium from BLM-treated epithelial cells increased production of CCL2 and CXCL2 in macrophages from NFATc3+/+ but not NFATc3+/- mice. CXCL2 promoter-pGL3 Luciferase reporter vector showed accentuated reporter activity when co-transfected with the NFATc3 expression vector. More importantly, exogenous administration of recombinant CXCL2 into NFATc3+/- mice increased fibrotic markers and exacerbated IPF phenotype in BLM treated mice. Collectively, our data demonstrate, for the first time, that NFATc3 regulates pulmonary fibrosis by regulating CCL2 and CXCL2 gene expression in macrophages.

Drug development and novel therapeutics to ensure a personalized approach in the treatment of systemic sclerosis

INTRODUCTION

Systemic sclerosis (SSc) is a systemic disease encompassing autoimmunity, vasculopathy, and fibrosis. SSc is still burdened by high mortality and morbidity rates. Recent advances in understanding the pathogenesis of SSc have identified novel potential therapeutic targets. Several clinical trials have been subsequently designed to evaluate the efficacy of a number of new drugs. The aim of this review is to provide clinicians with useful information about these novel molecules.

AREA COVERED

In this narrative review, we summarize the available evidence regarding the most promising targeted therapies currently under investigation for the treatment of SSc. These medications include kinase inhibitors, B-cell depleting agents, and interleukin inhibitors.

EXPERT OPINION

Over the next five years, several new, targeted drugs will be introduced in clinical practice for the treatment of SSc. Such pharmacological agents will expand the existing pharmacopoeia and enable a more personalized and effective approach to patients with SSc. Thus, it will not only possible to target a specific disease domain, but also different stages of the disease.

Investigational drugs for the treatment of scleroderma: what's new?

INTRODUCTION

Systemic sclerosis (SSc) is an orphan, chronic, autoimmune, fibrotic disease with unknown etiology characterized by progressive fibrosis of the skin and internal organs. SSc has the highest mortality, the deadliest among the connective tissue diseases, despite the introduction of new treatment options in the past decades.

AREAS COVERED

The aim of the current systematic review was to investigate new targeted therapy and their impact on disease progression, mainly focusing on phase I and II clinical trials within the past three years.

EXPERT OPINION

Despite recent groundbreaking advancements in understanding SSc pathophysiology, early diagnosis and early introduction of effective targeted treatments within the optimal window of opportunity to prevent irreversible disease damage still represents a significant clinical challenge. Ongoing significant research for new molecular and epigenetics pathways is of fundamental importance to offer new perspectives on disease phenotype and for the development of personalized treatment strategies.

Repurposing small molecules for Nephronophthisis and related renal ciliopathies

Nephronophthisis is an autosomal recessive tubulo-interstitial nephropathy, belonging to the ciliopathy disorders, characterized by fibrosis and/or cysts. It is the most common genetic cause of renal failure in children and young adults. Clinically and genetically heterogeneous, it is caused by variants in ciliary genes resulting in either an isolated kidney disease or syndromic forms in association with other manifestations of ciliopathy disorders. No curative treatment is currently available. Over the past two decades, advances in understanding disease mechanisms have identified several dysregulated signaling pathways, some shared with other cystic kidney diseases. Notably, molecules previously developed to target these pathways have shown promising beneficial effects in orthologous mouse models. In addition to these knowledge-based repurposing approaches, unbiased "in cellulo" phenotypic screens of "repurposing" libraries identified small molecules able to rescue the ciliogenesis defects observed in nephronophthisis conditions. Those compounds appeared to act on relevant pathways and, when tested, showed beneficial nephronophthisis-associated kidney and/or extra-renal defects in mice. In this review, we have summarized those studies which highlight the drug repurposing strategies in the context of a rare disorders such as nephronophthisis-related ciliopathies, with broad genetic heterogeneity and systemic manifestations but with shared disease mechanisms.

An update on current and emerging drug treatments for idiopathic pulmonary fibrosis

INTRODUCTION

Idiopathic Pulmonary Fibrosis (IPF) is a progressive and devastating lung disease, characterized by progressive lung scarring.

AREAS COVERED

Prior to antifibrotic therapy (pirfenidone and nintedanib), there was no validated pharmaceutical therapy for IPF. Both antifibrotics can slow disease progression, however, IPF remains a detrimental disease with poor prognosis and treated survival rates of less than 7 years from diagnosis. Despite their effect the disease remains non-reversible and progressing whilst their side effect profile is often challenging. Treatment of comorbidities is also crucial. In this review, we discuss the current pharmacological management as well as management of comorbidities and symptoms. We also reviewed clinicaltrials.gov and summarised all the mid to late stage clinical trials (phase II and III) registered in IPF over the last 7 years and discuss the most promising drugs in clinical development.

EXPERT OPINION

Future for IPF management will need to focus on current unresolved issues. First a primary pathogenetic pathway has not been clearly identified. Future management may involve a combination of brushstroke approach with antifibrotics with targeted treatments for specific pathways in patient subsets following an 'oncological' approach. Another unmet need is management of exacerbations, which are deathly in most cases as well as either treating or preventing lung cancer.

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.

Discovery of indoline-based derivatives as effective ROCK2 inhibitors for the potential new treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and devastating lung disease with a median survival of only 3-5 years. Due to the lack of effective therapy, IPF threatens human health. Recently, increasing reports have indicated that Rho-associated coiled-coil protein kinases (ROCKs) play important roles in the development of IPF and might represent a novel target for the treatment of IPF. Herein, a new series of selective ROCK2 inhibitors based on indoline were designed and synthesized. Structural modification resulted in optimized compound 9b with an IC₅₀ value of 6 nM against ROCK2 and the inhibition of collagen gel contraction. Cellular assays demonstrated that 9b could significantly suppress the expression of collagen I and α-SMA, and inhibited ROCK signaling pathway. Oral administration of compound 9b (10 mg/kg) exerted more significant anti-pulmonary fibrosis effects than nintedanib (100 mg/kg) and KD025 (100 mg/kg) in a bleomycin-induced IPF rat model, suggesting that 9b could serve as a potential lead compound for the treatment of IPF.

Application and Study of ROCK Inhibitors in Pulmonary Fibrosis: Recent Developments and Future Perspectives

Rho-associated coiled-coil-containing kinases (ROCKs), serine/threonine protein kinases, were initially identified as downstream targets of the small GTP-binding protein Rho. Pulmonary fibrosis (PF) is a lethal disease with limited therapeutic options and a particularly poor prognosis. Interestingly, ROCK activation has been demonstrated in PF patients and in animal PF models, making it a promising target for PF treatment. Many ROCK inhibitors have been discovered, and four of these have been approved for clinical use; however, no ROCK inhibitors are approved for the treatment of PF patients. In this article, we describe ROCK signaling pathways and the structure-activity relationship, potency, selectivity, binding modes, pharmacokinetics (PKs), biological functions, and recently reported inhibitors of ROCKs in the context of PF. We will also focus our attention on the challenges to be addressed when targeting ROCKs and discuss the strategy of ROCK inhibitor use in the treatment of PF.

VGLL3 is a mechanosensitive protein that promotes cardiac fibrosis through liquid-liquid phase separation

Myofibroblasts cause tissue fibrosis by producing extracellular matrix proteins, such as collagens. Humoral factors like TGF-β, and matrix stiffness are important for collagen production by myofibroblasts. However, the molecular mechanisms regulating their ability to produce collagen remain poorly characterised. Here, we show that vestigial-like family member 3 (VGLL3) is specifically expressed in myofibroblasts from mouse and human fibrotic hearts and promotes collagen production. Further, substrate stiffness triggers VGLL3 translocation into the nucleus through the integrin β1-Rho-actin pathway. In the nucleus, VGLL3 undergoes liquid-liquid phase separation via its low-complexity domain and is incorporated into non-paraspeckle NONO condensates containing EWS RNA-binding protein 1 (EWSR1). VGLL3 binds EWSR1 and suppresses miR-29b, which targets collagen mRNA. Consistently, cardiac fibrosis after myocardial infarction is significantly attenuated in Vgll3-deficient mice, with increased miR-29b expression. Overall, our results reveal an unrecognised VGLL3-mediated pathway that controls myofibroblasts' collagen production, representing a novel therapeutic target for tissue fibrosis.

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.

Inhibition of ROCK ameliorates pulmonary fibrosis by suppressing M2 macrophage polarisation through phosphorylation of STAT3

BACKGROUND

Emerging evidence provides mechanistic insights into the pathogenesis of pulmonary fibrosis (PF), and rare anti-PF therapeutic method has promising effect in its treatment. Rho-associated coiled-coil kinases (ROCK) inhibition significantly ameliorates bleomycin-induced PF and decreases macrophage infiltration, but the mechanism remains unclear. We established bleomycin and radiation-induced PF to identify the activity of WXWH0265, a newly designed unselective ROCK inhibitor in regulating macrophages.

METHODS

Bleomycin-induced PF was induced by intratracheal instillation and radiation-induced PF was induced by bilateral thoracic irradiation. Histopathological techniques (haematoxylin and eosin, Masson's trichrome and immunohistochemistry) and hydroxyproline were used to evaluate PF severity. Western blot, quantitative real-time reverse transcription-polymerase chain reaction and flow cytometry were performed to explore the underlying mechanisms. Bone marrow-derived macrophages (BMDMs) were used to verify their therapeutic effect. Clodronate liposomes were applied to deplete macrophages and to identify the therapeutic effect of WXWH0265.

RESULTS

Therapeutic administration of ROCK inhibitor ameliorates bleomycin-induced PF by inhibiting M2 macrophages polarisation. ROCK inhibitor showed no significant anti-fibrotic effect in macrophages-depleted mice. Treatment with WXWH0265 demonstrated superior protection effect in bleomycin-induced PF compared with positive drugs. In radiation-induced PF, ROCK inhibitor effectively ameliorated PF. Fibroblasts co-cultured with supernatant from various M2 macrophages phenotypes revealed that M2 macrophages stimulated by interleukin-4 promoted extracellular matrix production. Polarisation of M2 macrophages was inhibited by ROCK inhibitor treatment in vitro. The p-signal transducer and activator of transcription 3 (STAT3) in lung tissue and BMDMs was significantly decreased in PF in vivo and vitro after treated with ROCK inhibitors.

CONCLUSION

Inhibiting ROCK could significantly attenuate bleomycin- and radiation-induced PF by regulating the macrophages polarisation via phosphorylation of STAT3. WXWH0265 is a kind of efficient unselective ROCK inhibitor in ameliorating PF. Furthermore, the results provide empirical evidence that ROCK inhibitor, WXWH0265 is a potential drug to prevent the development of PF.

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.

Evaluating a Specific Dual ROCK Inhibitor against Bleomycin-Induced Idiopathic Pulmonary Fibrosis in Rats

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and fatal lung disease. Rho-associated protein kinases (ROCK) 1/2 are promising therapeutic targets for the treatment of IPF. However, a single inhibition of each of them is insufficient to prevent bleomycin-induced lung fibrosis. The current work reported that bleomycin-induced lung fibrosis can be reduced by dual inhibition of ROCK1/2 with compound 1. We evaluated the dual-selective ROCK1/2 inhibition activity of compound 1, its toxicity, and its preliminary efficacy on bleomycin-induced lung fibrosis. In vitro, compound 1 served as the ROCK1/2 inhibitor with half-maximal inhibitory concentration (IC50) values of 165 ±10.4 nM for ROCK1 and 16.1 ± 2.82 nM for ROCK2. In NIH/3T3 cells, compound 1 inhibited the mRNA expression of COL 1A1 and α-SMA. At therapeutic levels, compound 1 exhibited neither hepatic nor cardiac toxicity, also no CYP450 enzyme inhibition. In vivo, compound 1 had good pharmacokinetic properties, and its oral administration reduced bleomycin-induced pulmonary fibrosis in rats. All the outcomes prove the drug-like characteristics of compound 1 for the treatment of IPF.

MicroRNAs as the critical regulators of cell migration and invasion in thyroid cancer

Thyroid cancer (TC) is one of the most frequent endocrine malignancies that is more common among females. Tumor recurrence is one of the most important clinical manifestations in differentiated TC which is associated with different factors including age, tumor size, and histological features. Various molecular processes such as genetic or epigenetic modifications and non-coding RNAs are also involved in TC progression and metastasis. The epithelial-to-mesenchymal transition (EMT) is an important biological process during tumor invasion and migration that affects the initiation and transformation of early-stage tumors into invasive malignancies. A combination of transcription factors, growth factors, signaling pathways, and epigenetic regulations affect the thyroid cell migration and EMT process. MicroRNAs (miRNAs) are important molecular factors involved in tumor metastasis by regulation of EMT-activating signaling pathways. Various miRNAs are involved in the signaling pathways associated with TC metastasis which can be used as diagnostic and therapeutic biomarkers. Since, the miRNAs are sensitive, specific, and non-invasive, they can be suggested as efficient and optimal biomarkers of tumor invasion and metastasis. In the present review, we have summarized all of the miRNAs which have been significantly involved in thyroid tumor cells migration and invasion. We also categorized all of the reported miRNAs based on their cellular processes to clarify the molecular role of miRNAs during thyroid tumor cell migration and invasion. This review paves the way of introducing a non-invasive diagnostic and prognostic panel of miRNAs in aggressive and metastatic TC patients.

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.

Cytoplasmic Clusterin Suppresses Lung Cancer Metastasis by Inhibiting the ROCK1-ERK Axis

Simple Summary

We show that CLU, especially cytoplasmic precursor CLU, is downregulated in lung cancer and correlates with poor survival. The silencing of CLU promotes lung cancer cell migration and invasion, while the overexpression of CLU potently inhibits these phenomena. Interestingly, secretory CLU proteins are slightly decreased in lung cancer tissue and fail to exert similar anti-metastatic effects like cytoplasmic precursor CLU, demonstrating that cytoplasmic precursor CLU is the primary functional isoform of CLU, which exerts the anti-metastatic effects of lung cancer. Mechanistically, cytoplasmic precursor CLU binds ROCK1 to decrease phosphorylation of ERK1/2 by inhibiting the kinase activity of ROCK1, leading to an anti-metastatic effect in lung cancer cells. These findings reveal a novel insight into the function and regulation of cytoplasmic CLU in lung cancer, which might be a potential target for the diagnosis and treatment of metastatic lung cancer.

Abstract

Clusterin (CLU) is a heterodimeric glycoprotein that has been detected in diverse human tissues and implicated in many cellular processes. Accumulating evidence indicates that the expression of secreted CLU correlates with the progression of cancers. However, the molecular mechanisms underlying its tumor-suppressive roles are incompletely uncovered. In this study, we demonstrate that precursor CLU is widely downregulated in lung cancer tissue, in which secretory CLU proteins are slightly decreased. Impressively, overexpressing CLU potently inhibits the migration, invasion and metastasis of lung cancer cells, whereas silencing CLU promotes this behavior; however, it appears that secretory CLU fails to exert similar anti-metastatic effects. Interestingly, the cytoplasmic precursor CLU binds ROCK1 to abrogate the interaction between ROCK1 and ERK and impair ERK activity, leading to the suppression of lung cancer invasiveness. Meanwhile, the expression of CLU was remarkably diminished in lung cancer bone metastasis loci when compared with subcutaneous tumors in the mouse model and hardly detected in the bone metastasis loci of lung cancer patients when compared with the primary. These findings reveal a novel insight into the function and regulation of cytoplasmic CLU in lung cancer, which might be a potential target for the diagnosis and treatment of metastatic lung cancer.

Uncaria Rhynchophylla attenuates angiotensin Ⅱ-induced myocardial fibrosis via suppression of the RhoA/ROCK1 pathway

Uncaria rhynchophylla (UR), a traditional Chinese medicine, has been proven effective in treating hypertensive patients in China. However, the mechanisms of action of UR in reducing hypertension and myocardial fibrosis are still unclear. The purpose of this study was to explore the role of UR in an angiotensin Ⅱ (Ang Ⅱ) induced mouse model. The mice were randomly divided into 5 groups and infused with Ang Ⅱ (500 ng/kg/min) or saline, then administered UR (0.78, 1.56 or 3.12 g/kg/d) or saline for 4 weeks. UR treatment significantly attenuated the elevation of blood pressure caused by Ang Ⅱ. It enhanced myocardial function and attenuated the increase in the heart weight index and the pathological changes in the Ang Ⅱ-induced hypertensive mice. Furthermore, UR treatment inhibited cardiac fibrosis and significantly down-regulated collagen I, collagen Ⅲ, and α-SMA protein expression in cardiac tissues. UR also attenuated the expression of RhoA, ROCK1, CTGF, and TGF-β1. In cultured cardiac fibroblasts stimulated with Ang Ⅱ, UR significantly down-regulated the expression of Collagen I, Collagen III, RhoA, ROCK1, and α-SMA. In summary, UR can significantly attenuate Ang Ⅱ-induced hypertension and cardiac fibrosis, partly via suppression of the RhoA/ROCK1 signaling pathway.

Pathogenic Mechanisms Underlying Idiopathic Pulmonary Fibrosis

The pathogenesis of idiopathic pulmonary fibrosis (IPF) involves a complex interplay of cell types and signaling pathways. Recurrent alveolar epithelial cell (AEC) injury may occur in the context of predisposing factors (e.g., genetic, environmental, epigenetic, immunologic, and gerontologic), leading to metabolic dysfunction, senescence, aberrant epithelial cell activation, and dysregulated epithelial repair. The dysregulated epithelial cell interacts with mesenchymal, immune, and endothelial cells via multiple signaling mechanisms to trigger fibroblast and myofibroblast activation. Recent single-cell RNA sequencing studies of IPF lungs support the epithelial injury model. These studies have uncovered a novel type of AEC with characteristics of an aberrant basal cell, which may disrupt normal epithelial repair and propagate a profibrotic phenotype. Here, we review the pathogenesis of IPF in the context of novel bioinformatics tools as strategies to discover pathways of disease, cell-specific mechanisms, and cell-cell interactions that propagate the profibrotic niche.

Rho Kinases in Embryonic Development and Stem Cell Research

The Rho-associated coiled-coil containing kinases (ROCKs or Rho kinases) belong to the AGC (PKA/PKG/PKC) family of serine/threonine kinases and are major downstream effectors of small GTPase RhoA, a key regulator of actin-cytoskeleton reorganization. The ROCK family contains two members, ROCK1 and ROCK2, which share 65% overall identity and 92% identity in kinase domain. ROCK1 and ROCK2 were assumed to be functionally redundant, based largely on their major common activators, their high degree kinase domain homology, and study results from overexpression with kinase constructs or chemical inhibitors. ROCK signaling research has expanded to all areas of biology and medicine since its discovery in 1996. The rapid advance is befitting ROCK’s versatile functions in modulating various cell behavior, such as contraction, adhesion, migration, proliferation, polarity, cytokinesis, and differentiation. The rapid advance is noticeably driven by an extensive linking with clinical medicine, including cardiovascular abnormalities, aberrant immune responsive, and cancer development and metastasis. The rapid advance during the past decade is further powered by novel biotechnologies including CRISPR-Cas and single cell omics. Current consensus, derived mainly from gene targeting and RNA interference approaches, is that the two ROCK isoforms have overlapping and distinct cellular, physiological and pathophysiology roles. In this review, we present an overview of the milestone discoveries in ROCK research. We then focus on the current understanding of ROCK signaling in embryonic development, current research status using knockout and knockin mouse models, and stem cell research.

ROCK2 inhibition attenuates profibrogenic immune cell function to reverse thioacetamide-induced liver fibrosis

Background & Aims

Fibrosis, the primary cause of morbidity in chronic liver disease, is induced by pro-inflammatory cytokines, immune cell infiltrates, and tissue resident cells that drive excessive myofibroblast activation, collagen production, and tissue scarring. Rho-associated kinase 2 (ROCK2) regulates key pro-fibrotic pathways involved in both inflammatory reactions and altered extracellular matrix remodelling, implicating this pathway as a potential therapeutic target.

Methods

We used the thioacetamide-induced liver fibrosis model to examine the efficacy of administration of the selective ROCK2 inhibitor KD025 to prevent or treat liver fibrosis and its impact on immune composition and function.

Results

Prophylactic and therapeutic administration of KD025 effectively attenuated thioacetamide-induced liver fibrosis and promoted fibrotic regression. KD025 treatment inhibited liver macrophage tumour necrosis factor production and disrupted the macrophage niche within fibrotic septae. ROCK2 targeting in vitro directly regulated macrophage function through disruption of signal transducer and activator of transcription 3 (STAT3)/cofilin signalling pathways leading to the inhibition of pro-inflammatory cytokine production and macrophage migration. In vivo, KDO25 administration significantly reduced STAT3 phosphorylation and cofilin levels in the liver. Additionally, livers exhibited robust downregulation of immune cell infiltrates and diminished levels of retinoic acid receptor-related orphan receptor gamma (RORγt) and B-cell lymphoma 6 (Bcl6) transcription factors that correlated with a significant reduction in liver IL-17, splenic germinal centre numbers and serum IgG.

Conclusions

As IL-17 and IgG–Fc binding promote pathogenic macrophage differentiation, together our data demonstrate that ROCK2 inhibition prevents and reverses liver fibrosis through direct and indirect effects on macrophage function and highlight the therapeutic potential of ROCK2 inhibition in liver fibrosis.

Lay summary

By using a clinic-ready small-molecule inhibitor, we demonstrate that selective ROCK2 inhibition prevents and reverses hepatic fibrosis through its pleiotropic effects on pro-inflammatory immune cell function. We show that ROCK2 mediates increased IL-17 production, antibody production, and macrophage dysregulation, which together drive fibrogenesis in a model of chemical-induced liver fibrosis. Therefore, in this study, we not only highlight the therapeutic potential of ROCK2 targeting in chronic liver disease but also provide previously undocumented insights into our understanding of cellular and molecular pathways driving the liver fibrosis pathology.

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ROCK2 inhibition with the small-molecule inhibitor KD025 prevents and reverses hepatoxin-induced liver fibrosis.

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ROCK2 inhibition attenuates profibrogenic immune function.

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KD025 exerts direct effects on liver macrophages resulting in decreased TNF secretion and impeded migration.

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KD025 administration attenuates T cell IL-17 production and B-cell IgG production, which indirectly contributes to downregulation of profibrogenic macrophage function.

The Design, Synthesis and Evaluation of Rho-kinase Inhibitory Activity of 4-aryl-thiazole-2-amines

Rho-associated kinases (ROCK) are a class of serine/threonine kinases that play important roles in various biological processes. ROCK are becoming attractive targets for drug designing. A novel scaffold was designed according to molecular hybridization strategy, then a series of 4-aryl-5-aminomethyl-thiazole-2-amines were synthesized, and their inhibitory activities on ROCK were screened by enzyme-linked immunosorbent assay (ELISA). The results showed that 4-aryl-5-aminomethyl-thiazole-2-amines derivatives displayed certain ROCK II inhibitory activities. The IC₅₀ value of the most potent compound 4v was found to be 20 nM. The preliminary structure-activity-relationship investigation showed that compounds with 4-pyridine substitution were generally found to be more potent than compounds with 3-pyridine substitution. The molecular docking studies indicated that more optimization work needs to conduct to obtain more potent ROCK inhibitors.

Serine-Threonine Kinase inhibition as antifibrotic therapy: TGF-β and ROCK inhibitors

Serine-threonine kinases mediate the phosphorylation of intracellular protein targets, transferring a phosphorus group from an ATP molecule to the specific amino acid residues within the target proteins. Serine-threonine kinases regulate multiple key cellular functions. From this large group of kinases, transforming growth factor beta (TGF-β) through the serine-threonine activity of its receptors and Rho kinase (ROCK) play an important role in the development and maintenance of fibrosis in various human diseases, including systemic sclerosis. In recent years, multiple drugs targeting and inhibiting these kinases, have been developed, opening the possibility of becoming potential antifibrotic agents of clinical value for treating fibrotic diseases. This review analyzes the contribution of TGF- β and ROCK-mediated serine-threonine kinase molecular pathways to the development and maintenance of pathological fibrosis and the potential clinical use of their inhibition.

Rho/ROCK Inhibition Promotes TGF-β3-Induced Tenogenic Differentiation in Mesenchymal Stromal Cells

Mesenchymal stromal cells (MSC) represent a promising therapeutic tool for tendon regeneration. Their tenogenic differentiation is crucial for tissue engineering approaches and may support their beneficial effects after cell transplantation in vivo. The transforming growth factor (TGF)-β, signalling via intracellular Smad molecules, is a potent paracrine mediator of tenogenic induction. Moreover, scaffold topography or tendon matrix components induced tenogenesis via activation of the Rho/ROCK cascade, which, however, is also involved in pathological adaptations in extracellular matrix pathologies. The aim of this study was to investigate the interplay of Rho/ROCK and TGF-β3/Smad signalling in tenogenic differentiation in both human and equine MSC. Primary equine and human MSC isolated from adipose tissue were cultured as monolayers or on tendon-derived decellularized scaffolds to evaluate the influence of the ROCK inhibitor Y-27632 on TGF-β3-induced tenogenic differentiation. The MSC were incubated with and without TGF-β3 (10 ng/ml), Y-27632 (10 μM), or both. On day 1 and day 3, the signalling pathway of TGF-β and the actin cytoskeleton were visualized by Smad 2/3 and phalloidin staining, and gene expression of signalling molecules and tendon markers was assessed. ROCK inhibition was confirmed by disruption of the actin cytoskeleton. Activation of Smad 2/3 with nuclear translocation was evident upon TGF-β3 stimulation. Interestingly, this effect was most pronounced with additional ROCK inhibition in both species (p < 0.05 in equine MSC). In line with that, the tendon marker scleraxis showed the strongest upregulation when TGF-β3 and ROCK inhibition were combined (p < 0.05 in human MSC). The regulation pattern of tendon extracellular matrix components and the signalling molecules TGF-β3 and Smad 8 showed differences between human and equine MSC. The obtained results showed that ROCK inhibition promotes the TGF-β3/Smad 2/3 axis, with possible implications for future MSC priming regimes in tendon therapy.

Exogenous extracellular matrix proteins decrease cardiac fibroblast activation in stiffening microenvironment through CAPG

Controlling fibrosis is an essential part of regenerating the post-ischemic heart. In the post-ischemic heart, fibroblasts differentiate to myofibroblasts that produce collagen-rich matrix to physically stabilize the infarct area. Infarct models in adult mice result in permanent scarring unlike newborn animals which fully regenerate. Decellularized extracellular matrix (dECM) hydrogels derived from early-aged hearts have been shown to be a transplantable therapy that preserves heart function and stimulates cardiomyocyte proliferation and vascularization. In this study, we investigate the anti-fibrotic effects of injectable dECM hydrogels in a cardiac explant model in the context of age-associated tissue compliance. Treatments with adult and fetal dECM hydrogels were tested for molecular effects on cardiac fibroblast activation and fibrosis. Altered sensitivity of fibroblasts to the mechanosignaling of the remodeling microenvironment was evaluated by manipulating the native extracellular matrix in explants and also with elastomeric substrates in the presence of dECM hydrogels. The injectable fetal dECM hydrogel treatment decreases fibroblast activation and contractility and lowers the stiffness-mediated increases in fibroblast activation observed in stiffened explants. The anti-fibrotic effect of dECM hydrogel is most observable at highest stiffness. Experiments with primary cells on elastomeric substrates with dECM treatment support this phenomenon. Transcriptome analysis indicated that dECM hydrogels affect cytoskeleton related signaling including Macrophage capping protein (CAPG) and Leupaxin (LPXN). CAPG was down-regulated by the fetal dECM hydrogel. LPXN expression was decreased by stiffening the explants; however, this effect was reversed by dECM hydrogel treatment. Pharmacological disruption of cytoskeleton polymerization lowered fibroblast activation and CAPG levels. Knocking down CAPG expression with siRNA inhibited fibroblast activation and collagen deposition. Collectively, fibroblast activation is dependent on cooperative action of extracellular molecular signals and mechanosignaling by cytoskeletal integrity.

Development of Anti-fibrotic Therapy in Stricturing Crohn's Disease: Lessons from Randomized Trials in Other Fibrotic Diseases

Intestinal fibrosis is considered an inevitable complication of Crohn's disease (CD) that results in symptoms of obstruction and stricture formation. Endoscopic or surgical treatment is required to treat the majority of patients. Progress in the management of stricturing CD is hampered by the lack of effective anti-fibrotic therapy; however, this situation is likely to change because of recent advances in other fibrotic diseases of the lung, liver and skin. In this review, we summarized data from randomized controlled trials (RCT) of anti-fibrotic therapies in these conditions. Multiple compounds have been tested for the anti-fibrotic effects in other organs. According to their mechanisms, they were categorized into growth factor modulators, inflammation modulators, 5-hydroxy-3-methylgultaryl-coenzyme A (HMG-CoA) reductase inhibitors, intracellular enzymes and kinases, renin-angiotensin system (RAS) modulators and others. From our review of the results from the clinical trials and discussion of their implications in the gastrointestinal tract, we have identified several molecular candidates that could serve as potential therapies for intestinal fibrosis in CD.

ROCK2, a critical regulator of immune modulation and fibrosis has emerged as a therapeutic target in chronic graft-versus-host disease

Chronic graft-versus-host disease (cGVHD) is an immune-mediated disorder characterized by chronic inflammation and fibrosis. Rho-associated coiled-coil-containing protein kinases (ROCKs) are key coordinators of tissue response to injury, regulating multiple functions, such as gene expression and cell migration, proliferation and survival. Relevant to cGVHD and autoimmunity, only the ROCK2 isoform drives a pro-inflammatory type 17 helper T (Th17) cell response. Moreover, ROCK2 inhibition shifts the Th17/regulatory T (Treg) cell balance toward Treg cells and restores immune homeostasis in animal models of autoimmunity and cGVHD. Furthermore, the selective inhibition of ROCK2 by belumosudil reduces fibrosis by downregulating both transforming growth factor-β signaling and profibrotic gene expression, thereby impeding the creation of focal adhesions. Consistent with its anti-inflammatory and antifibrotic activities, belumosudil has demonstrated efficacy in clinical studies, resulting in an overall response rate of >70% in patients with cGVHD who failed 2 to 5 prior lines of systemic therapy. In summary, selective ROCK2 inhibition has emerged as a promising novel therapeutic approach for treating cGVHD and other immunologic diseases with unique mechanisms of action, targeting both immune imbalance and detrimental fibrotic responses.

Fibrotic Idiopathic Interstitial Lung Disease: The Molecular and Cellular Key Players

Interstitial lung diseases (ILDs) that are known as diffuse parenchymal lung diseases (DPLDs) lead to the damage of alveolar epithelium and lung parenchyma, culminating in inflammation and widespread fibrosis. ILDs that account for more than 200 different pathologies can be divided into two groups: ILDs that have a known cause and those where the cause is unknown, classified as idiopathic interstitial pneumonia (IIP). IIPs include idiopathic pulmonary fibrosis (IPF), non-specific interstitial pneumonia (NSIP), cryptogenic organizing pneumonia (COP) known also as bronchiolitis obliterans organizing pneumonia (BOOP), acute interstitial pneumonia (AIP), desquamative interstitial pneumonia (DIP), respiratory bronchiolitis-associated interstitial lung disease (RB-ILD), and lymphocytic interstitial pneumonia (LIP). In this review, our aim is to describe the pathogenic mechanisms that lead to the onset and progression of the different IIPs, starting from IPF as the most studied, in order to find both the common and standalone molecular and cellular key players among them. Finally, a deeper molecular and cellular characterization of different interstitial lung diseases without a known cause would contribute to giving a more accurate diagnosis to the patients, which would translate to a more effective treatment decision.

RhoA/ROCK Signaling Regulates TGF-β1-Induced Fibrotic Effects in Human Pterygium Fibroblasts through MRTF-A

PURPOSE

The overexpression of transforming growth factor-beta1 (TGF-β1) after surgical excision often leads to excessive fibrosis, indicating the recurrence of pterygium. The aims of the present in vitro study were to investigate the role of RhoA/ROCK signaling in regulating fibrotic effects of primary human pterygium fibroblasts (HPFs), as well as to explore the possible mechanisms of these effects.

METHODS

Pterygium samples were obtained from surgery, and profibrotic activation was induced by TGF-β1. Cell proliferation was detected by CCK-8 assay; cell migration was detected by wound healing assay; quantitative real-time PCR and Western blot were used to detect the effects of TGF-β1 and the role of RhoA/ROCK signaling in the synthesis of alpha-smooth muscle actin (a-SMA), type I and III collagen (COL1 and COL3), and matrix metalloproteinase-9 (MMP9) in HPFs. The changes of signaling pathways were detected by Western blot; and pharmaceutical inhibition of RhoA/ROCK signaling and its downstream MRFT-A/SRF transcription pathway were used to assess their possible mechanism in HPFs fibrosis.

RESULTS

ROCK inhibitor Y-27632 decreased TGF-β1-induced cell proliferation and migration, reduced the TGF-β1-induced expression of profibrotic markers in HPFs, and suppressed TGF-β1-induced nuclear accumulation of Myocardin-related transcription factor A (MRTF-A) as well as accompanied elevation of F/G-actin ratio in HPFs. MRTF-A/Serum response factor (SRF) inhibitor CCG-100602 attenuated the TGF-β1-induced α-SMA expression and reduced myofibroblast activation in HPFs.

CONCLUSIONS

RhoA/ROCK signaling played a pivotal role in TGF-β1-induced fibrosis and myofibroblast activation in HPFs at least in part by inactivating the downstream MRTF-A/SRF transcriptional pathway.

Therapeutic and diagnostic targeting of fibrosis in metabolic, proliferative and viral disorders

Fibrosis is a common denominator in many pathologies and crucially affects disease progression, drug delivery efficiency and therapy outcome. We here summarize therapeutic and diagnostic strategies for fibrosis targeting in atherosclerosis and cardiac disease, cancer, diabetes, liver diseases and viral infections. We address various anti-fibrotic targets, ranging from cells and genes to metabolites and proteins, primarily focusing on fibrosis-promoting features that are conserved among the different diseases. We discuss how anti-fibrotic therapies have progressed over the years, and how nanomedicine formulations can potentiate anti-fibrotic treatment efficacy. From a diagnostic point of view, we discuss how medical imaging can be employed to facilitate the diagnosis, staging and treatment monitoring of fibrotic disorders. Altogether, this comprehensive overview serves as a basis for developing individualized and improved treatment strategies for patients suffering from fibrosis-associated pathologies.

Belumosudil for Chronic Graft-versus-Host Disease (cGVHD) After 2 or More Prior Lines of Therapy: The ROCKstar Study

Belumosudil, a selective ROCK2 inhibitor, was well tolerated in heavily pretreated subjects, with 44% continuing treatment beyond 1 year.

Belumosudil demonstrated efficacy in patients with SR cGVHD, with responses in all organs and after failure of ibrutinib/ruxolitinib.

Belumosudil, an investigational oral selective inhibitor of Rho-associated coiled-coil–containing protein kinase 2 (ROCK2), reduces type 17 and follicular T helper cells via downregulation of STAT3 and enhances regulatory T cells via upregulation of STAT5. Belumosudil may effectively treat patients with chronic graft-versus-host disease (cGVHD), a major cause of morbidity and late nonrelapse mortality after an allogeneic hematopoietic cell transplant. This phase 2 randomized multicenter registration study evaluated belumosudil 200 mg daily (n = 66) and 200 mg twice daily (n = 66) in subjects with cGVHD who had received 2 to 5 prior lines of therapy. The primary end point was best overall response rate (ORR). Duration of response (DOR), changes in Lee Symptom Scale score, failure-free survival, corticosteroid dose reductions, and overall survival were also evaluated. Overall median follow-up was 14 months. The best ORR for belumosudil 200 mg daily and 200 mg twice daily was 74% (95% confidence interval [CI], 62-84) and 77% (95% CI, 65-87), respectively, with high response rates observed in all subgroups. All affected organs demonstrated complete responses. The median DOR was 54 weeks; 44% of subjects have remained on therapy for ≥1 year. Symptom reduction with belumosudil 200 mg daily and 200 mg twice daily was reported in 59% and 62% of subjects, respectively. Adverse events (AEs) were consistent with those expected in patients with cGVHD receiving corticosteroids and other immunosuppressants. Sixteen subjects (12%) discontinued belumosudil because of possible drug-related AEs. Belumosudil, a promising therapy for cGVHD, was well tolerated with clinically meaningful responses. This trial was registered at www.clinicaltrials.gov as #NCT03640481.