Targeting the RhoA-ROCK pathway to reverse T-cell dysfunction in SLE

Roles of IRF4 in various immune cells in systemic lupus erythematosus

Interferon regulatory factor 4 (IRF4) is a member of IRF family of transcription factors which mainly regulates the transcription of IFN. IRF4 is restrictively expressed in immune cells such as T and B cells, macrophages, as well as DC. It is essential for the development and function of these cells. Since these cells take part in the homeostasis of the immune system and dysfunction of them contributes to the initiation and progress of systemic lupus erythematosus (SLE), the roles of IRF4 in the SLE development becomes an important topic. Here we systemically discuss the biological characteristics of IRF4 in various immune cells and analyze the pathologic effects of IRF4 alteration in SLE and the potential targeting therapeutics of SLE.

New and emerging therapies for systemic lupus erythematosus

Systemic Lupus Erythematosus (SLE) and lupus nephritis treatment is still based on non-specific immune suppression despite the first biological therapy for the disease having been approved more than a decade ago. Intense basic and translational research has uncovered a multitude of pathways that are actively being evaluated as treatment targets in SLE and lupus nephritis, with two new medications receiving FDA approval in the last 3 years. Herein we provide an overview of targeted therapies for SLE including medications targeting the B lymphocyte compartment, intracellular signaling, co-stimulation, and finally the interferons and other cytokines.

Potential role of RhoA GTPase regulation in type interferon signaling in systemic lupus erythematosus

OBJECTIVE

Systemic lupus erythematosus (SLE) is an autoimmune disorder characterized by abnormal activation of the type I interferon (IFN) pathway, which results in tissue inflammation and organ damage. We explored the role of the RhoA GTPase in the type I IFN activation pathway to provide a potential basis for targeting GTPase signaling for the treatment of SLE.

METHODS

Total RNA was extracted from peripheral blood mononuclear cells (PBMCs) of SLE patients and healthy controls, and the mRNA expression levels of RhoA and IFN-stimulated genes were measured by SYBR Green quantitative reverse transcriptase-polymerase chain reaction. IFN-a-stimulated response element (ISRE)-luciferase reporter gene assays and Western blotting were conducted to assess the biologic function of RhoA. An enzyme-linked immunoassay (ELISA) measured C-X-C motif chemokine ligand 10 (CXCL10) protein expression.

RESULTS

Our studies demonstrate that the expression of RhoA in the PBMCs of SLE subjects was significantly higher than in healthy controls and positively correlated with type I IFN scores and type I IFN-stimulated gene (ISGs) expression levels. SiRNA-mediated knockdown of RhoA and the RhoA/ROCK inhibitor Y27632 reduced the activity of the type I IFN-induced ISRE, the signal transducer and activator of transcription 1 (STAT-1) phosphorylation, and the expression of CXCL10 and 2'-5'-oligoadenylate synthetase 1 (OAS1). Finally, we verified that Y27632 could significantly down-regulate the OAS1 and CXCL10 expression levels in the PBMCs of SLE patients.

CONCLUSION

Our study shows that RhoA positively regulates the activation of the type I IFN response pathway. Reducing the expression level of RhoA inhibits the abnormal activation of the type I IFN system, and the RhoA/ROCK inhibitor Y27632 decreases aberrant type I IFN signaling in SLE PBMCs, suggesting the possibility of targeting the RhoA GTPase for the treatment of SLE.

FUNDC1/PFKP-mediated mitophagy induced by KD025 ameliorates cartilage degeneration in osteoarthritis

Osteoarthritis (OA) is the most common joint disease, but no disease-modifying drugs have been approved for OA treatment. Mitophagy participates in mitochondrial homeostasis regulation by selectively clearing dysfunctional mitochondria, which might contribute to cartilage degeneration in OA. Here, we provide evidence of impaired mitophagy in OA chondrocytes, which exacerbates chondrocyte degeneration. Among the several classic mitophagy-regulating pathways and receptors, we found that FUNDC1 plays a key role in preserving chondrocyte homeostasis by inducing mitophagy. FUNDC1 knockdown in vitro and knockout in vivo decreased mitophagy and exacerbated mitochondrial dysfunction, exacerbating chondrocyte degeneration and OA progression. FUNDC1 overexpression via intra-articular injection of adeno-associated virus alleviated cartilage degeneration in OA. Mechanistically, our study demonstrated that PFKP interacts with and dephosphorylates FUNDC1 to induce mitophagy in chondrocytes. Further analysis identified KD025 as a candidate drug for restoring chondrocyte mitophagy by increasing the FUNDC1-PFKP interaction and thus alleviating cartilage degeneration in mice with DMM-induced OA. Our study highlights the role of the FUNDC1-PFKP interaction in chondrocyte homeostasis via mitophagy induction and identifies KD025 as a promising agent for treating OA by increasing chondrocyte mitophagy.

Design, Synthesis, and Biological Evaluation of an Orally Bioavailable, Potent, and Selective ROCK2 Inhibitor for Psoriasis Treatment

Psoriasis, a prevalent chronic skin disorder, remains a significant therapeutic obstacle. This study centers on rho-associated coiled-coil-containing kinase2 (ROCK2) as an advantageous target for treating psoriasis and identifies five potent and selective ROCK2 inhibitors (A31-35). Notably, A32-35 outperform KD025 in ROCK2/ROCK1 selectivity by up to 216-fold. Among these candidates, A31 emerged as an exceedingly promising molecule, showcasing remarkable inhibitory potency (IC50 = 3.7 ± 0.8 nM), 19-fold ROCK2/ROCK1 selectivity, and favorable pharmacokinetics. Insights from the binding mode study further underscored the pivotal role of interactions with Phe103 on the P-loop in determining the selectivity between ROCK1 and ROCK2. In an imiquimod-induced psoriasis-like mouse model, oral administration of A31 notably ameliorated symptoms by targeting the IL-23/Th17 axis. Based on these compelling findings, A31 was selected as a highly promising compound for further investigation as a potential treatment for psoriasis.

Navigating the landscape of Rho GTPase signalling system in autoimmunity: A bibliometric analysis spanning over three decades (1990 to 2023)

Ras-homologous (Rho) guanosine triphosphatases (GTPases) are considered a central player in regulating various biological processes, extending to immune regulation. Perturbations in Rho GTPase signalling have been implicated in immune-related dysregulation, contributing to the development of autoimmunity. This study presents a scientometric analysis exploring the interlink between the Rho GTPase signalling system and autoimmunity, while also delving into the trends of past studies. A total of 967 relevant publications from 1990 to 2023 were retrieved from the Web of Science Core Collection database after throrough manual filtering of irrelevant articles. The findings show an upward trajectory in publications related to this field since 2006. Over the past three decades, the United States of America (41.68%) emerged as the primary contributor in advancing our understanding of the association between the Rho GTPase signalling system and autoimmunity. Research in autoimmunity has mainly centered around therapeutic interventions, with an emphasis on studying leukocyte (macrophage) and endothelial remodelling. Interestingly, within the domains of multiple sclerosis and rheumatoid arthritis, the current focus has been directed towards comprehending the role of RhoA, Rac1, and Cdc42. Notably, certain subfamilies of Rho (such as RhoB and RhoC), Rac (including Rac2 and RhoG), Cdc42 (specifically RhoJ), and other atypical Rho GTPases (like RhoE and RhoH) consistently demonstrating compelling link with autoimmunity, but still warrants emphasis in the future study. Hence, strategic manipulation of the Rho signalling system holds immense promise as a pivotal approach to addressing the global challenge of autoimmunity.

SUMOylation of Rho-associated protein kinase 2 induces goblet cell metaplasia in allergic airways

Allergic asthma is characterized by goblet cell metaplasia and subsequent mucus hypersecretion that contribute to the morbidity and mortality of this disease. Here, we explore the potential role and underlying mechanism of protein SUMOylation-mediated goblet cell metaplasia. The components of SUMOylaion machinery are specifically expressed in healthy human bronchial epithelia and robustly upregulated in bronchial epithelia of patients or mouse models with allergic asthma. Intratracheal suppression of SUMOylation by 2-D08 robustly attenuates not only allergen-induced airway inflammation, goblet cell metaplasia, and hyperreactivity, but IL-13-induced goblet cell metaplasia. Phosphoproteomics and biochemical analyses reveal SUMOylation on K1007 activates ROCK2, a master regulator of goblet cell metaplasia, by facilitating its binding to and activation by RhoA, and an E3 ligase PIAS1 is responsible for SUMOylation on K1007. As a result, knockdown of PIAS1 in bronchial epithelia inactivates ROCK2 to attenuate IL-13-induced goblet cell metaplasia, and bronchial epithelial knock-in of ROCK2(K1007R) consistently inactivates ROCK2 to alleviate not only allergen-induced airway inflammation, goblet cell metaplasia, and hyperreactivity, but IL-13-induced goblet cell metaplasia. Together, SUMOylation-mediated ROCK2 activation is an integral component of Rho/ROCK signaling in regulating the pathological conditions of asthma and thus SUMOylation is an additional target for the therapeutic intervention of this disease.

Fasudil compensates podocyte injury via CaMK4/Rho GTPases signal and actin cytoskeleton-dependent activation of YAP in MRL/lpr mice

Deposition of immune complexes in the glomerulus leads to irreversible renal damage in lupus nephritis (LN), of which podocyte malfunction arises earlier. Fasudil, the only Rho GTPases inhibitor approved in clinical settings, possesses well-established renoprotective actions; yet, no studies addressed the amelioration derived from fasudil in LN. To clarify, we investigated whether fasudil exerted renal remission in lupus-prone mice. In this study, fasudil (20 mg/kg) was intraperitoneally administered to female MRL/lpr mice for 10 weeks. We report that fasudil administration swept antibodies (anti-dsDNA) and attenuated systemic inflammatory response in MRL/lpr mice, accompanied by preserving podocyte ultrastructure and averting immune complex deposition. Mechanistically, it repressed the expression of CaMK4 in glomerulopathy by preserving nephrin and synaptopodin expression. And fasudil further blocked cytoskeletal breakage in the Rho GTPases-dependent action. Further analyses showed that beneficial actions of fasudil on the podocytes required intra-nuclear YAP activation underlying actin dynamics. In addition, in vitro assays revealed that fasudil normalized the motile imbalance by suppressing intracellular calcium enrichment, thereby contributing to the resistance of apoptosis in podocytes. Altogether, our findings suggest that the precise manners of crosstalks between cytoskeletal assembly and YAP activation underlying the upstream CaMK4/Rho GTPases signal in podocytes is a reliable target for podocytopathies treatment, and fasudil might serve as a promising therapeutic agent to compensate for the podocyte injury in LN.

Modulating T Cell Phenotype and Function to Treat Hypertension

Hypertension is the leading modifiable risk factor of worldwide morbidity and mortality because of its effects on cardiovascular and renal end-organ damage. Unfortunately, BP control is not sufficient to fully reduce the risks of hypertension, underscoring the need for novel therapies that address end-organ damage in hypertension. Over the past several decades, the link between immune activation and hypertension has been well established, but there are still no therapies for hypertension that specifically target the immune system. In this review, we describe the critical role played by T cells in hypertension and hypertensive end-organ damage and outline potential therapeutic targets to modulate T-cell phenotype and function in hypertension without causing global immunosuppression.

Formulary Drug Review: Belumosudil

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Mechanistic and therapeutic perspectives of baicalin and baicalein on pulmonary hypertension: A comprehensive review

Pulmonary hypertension (PH) is a chronic and fatal disease, for which new therapeutic drugs and approaches are needed urgently. Baicalein and baicalin, the active compounds of the traditional Chinese medicine, Scutellaria baicalensis Georgi, exhibit a wide range of pharmacological activities. Numerous studies involving in vitro and in vivo models of PH have revealed that the treatment with baicalin and baicalein may be effective. This review summarizes the potential mechanisms driving the beneficial effects of baicalin and baicalein treatment on PH, including anti-inflammatory response, inhibition of pulmonary smooth muscle cell proliferation and endothelial-to-mesenchymal transformation, stabilization of the extracellular matrix, and mitigation of oxidative stress. The pharmacokinetics of these compounds have also been reviewed. The therapeutic potential of baicalin and baicalein warrants their continued study as natural treatments for PH.

Strategies of Targeting Inflammasome in the Treatment of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by multiple organ dysfunction resulting from the production of multiple autoantibodies and adaptive immune system abnormalities involving T and B lymphocytes. In recent years, inflammasomes have been recognized as an important component of innate immunity and have attracted increasing attention because of their pathogenic role in SLE. In short, inflammasomes regulate the abnormal differentiation of immune cells, modulate pathogenic autoantibodies, and participate in organ damage. However, due to the clinical heterogeneity of SLE, the pathogenic roles of inflammasomes are variable, and thus, the efficacy of inflammasome-targeting therapies is uncertain. To provide a foundation for the development of such therapeutic strategies, in this paper, we review the role of different inflammasomes in the pathogenesis of SLE and their correlation with clinical phenotypes and propose some corresponding treatment strategies.

A Mechanistic Insight into the Pathogenic Role of Interleukin 17A in Systemic Autoimmune Diseases

Interleukin 17A (IL-17A) has been put forward as a strong ally in our fight against invading pathogens across exposed epithelial surfaces by serving an antimicrobial immunosurveillance role in these tissues to protect the barrier integrity. Amongst other mechanisms that prevent tissue injury mediated by potential microbial threats and promote restoration of epithelial homeostasis, IL-17A attracts effector cells to the site of inflammation and support the host response by driving the development of ectopic lymphoid structures. Accumulating evidence now underscores an integral role of IL-17A in driving the pathophysiology and clinical manifestations in three potentially life-threatening autoimmune diseases, namely, systemic lupus erythematosus, Sjögren’s syndrome, and systemic sclerosis. Available studies provide convincing evidence that the abundance of IL-17A in target tissues and its prime source, which is T helper 17 cells (Th17) and double negative T cells (DNT), is not an innocent bystander but in fact seems to be prerequisite for organ pathology. In this regard, IL-17A has been directly implicated in critical steps of autoimmunity. This review reports on the synergistic interactions of IL-17A with other critical determinants such as B cells, neutrophils, stromal cells, and the vasculature that promote the characteristic immunopathology of these autoimmune diseases. The summary of observations provided by this review may have empowering implications for IL-17A-based strategies to prevent clinical manifestations in a broad spectrum of autoimmune conditions.

QRISK3-based analysis of cardiovascular risk factors in patients with long-term but well-controlled systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multisystem inflammatory disease of unknown etiology. Corticosteroids and immunosuppressive agents are the principal forms of treatment for this condition. While cardiovascular disease (CVD) is known to be a major cause of death in patients with SLE, there has been no improvement over the last few decades with regard to diagnosis, treatment, or prognosis. The QRISK3 algorithm is a new algorithm that includes SLE-related risk factors; this tool can predict the risk of CVD over a ten-year period. In this study, involving 180 patients, we compared the performance of the Framingham risk score, the recalibrated risk prediction SCORE, and QRISK3 for the assessment of CVD in patients with a long course of disease and low disease activity. Then, we used a more efficient algorithm, QRISK3 to identify the risk factors for CVD. This was a prospective and cross-sectional study involving 116 patients. All patients fulfilled the ACR criteria. The systemic lupus erythematosus disease activity index 2000 (SLEDAI-2K) is widely used to assess disease activity in SLE patients; patients with a SLEDAI-2K less than or equal to 4 are considered to be stable. Thus, we defined well-controlled patients as those with a SLEDAI-2K score less than or equal to 4. The dose of glucocorticoid (GC) that patients received was less or equal to 10 mg per day. We recorded and assessed a range of traditional risk factors, current treatments, comorbidities, data at the time of onset, and SLE-related evaluations. The QRISK3 score, and the relative risk (RR) that this score defined, were used to estimate the risk of CVD in patients with SLE. According to these relative risks, the patients were divided into low- (n=28), intermediate- (n=46), and high-relative risk (n=31) groups for subgroup analysis. Of the 116 patients enrolled, 105 were eligible to be assessed for the risk of CVD. By univariate analyses, the RR was significantly related with age at the time of enrolment (p<0.001), age at onset (p<0.001), resting heart rate (RHR) (p<0.001), present dose of GCs (p<0.001), present SLEDAI-2K (p=0.015), aerobic exercise (p<0.001), initial SLEDAI-2K (p<0.001), and initial dose of GCs (p=0.048). In the multiple linear regression model, the RR of CVD was significantly correlated with the initial SLEDAI-2K score (β=2.112, p<0.001), initial dose of GCs (β=-0.009, p=0.041), resting heart rate (β=0.241, p=0.003) and age at onset (β=-0.208, p=0.004). Pearson's correlation showed that RHR was significantly associated with aerobic exercise (r=-0.322, p=0.001). Subgroup analysis further identified a positive correlation between the history of nephritis, metabolic syndrome (MetS), aerobic exercise, present dose of GCs, and the RR of CVD. Patients with long-term but well-controlled SLE had a high relative risk of CVD and that this was associated with resting heart rate (P=0.003), history of lupus nephritis (P<0.001), initial SLEDAI-2K score (P<0.001), and metabolic syndrome (P=0.017). However, age at onset (P<0.001), use of hydroxychloroquine (P=0.30) and Mycophenolate mofetil (P=0.01), and the initial dose of glucocorticoid (P=0.049), were protective factors. Younger SLE patients had a significantly higher relative risk of CVD than older patients (p<0.001). QRISK3 detected more SLE patients at high risk of CVD when compared to the Framingham and recalibrate SCORE. To reduce the risk of CVD in SLE patients, measures should be taken both during the initial stages of disease and for long-term management.

Rho Kinase Expression in Giant Cell Arteritis: Validating pERM Intensity Score to Increase Sensitivity of Temporal Artery Biopsy

Objective

Aberrant rho-kinase (ROCK) activity is implicated in several vascular and immunologic disorders. We previously demonstrated increased ROCK activity in histopathologically negative temporal artery biopsies (TAB) in subjects with clinical Giant Cell Arteritis (GCA) compared to those without GCA. This current study aimed to examine ROCK activity in a larger cohort of biopsy-negative GCA subjects and to validate the prior findings.

Methods

Subjects were categorized into 2 groups based on clinical data 6-months after TAB: biopsy-negative GCA and controls without GCA. Paraffin-embedded TAB were stained for phosphorylated ezrin/radixin/moesin (pERM), a surrogate of ROCK activity, and scored by two pathologists blinded to clinical diagnosis using a previously derived scoring system measuring staining intensity in three areas of the vessel

Results

36 subjects with biopsy-negative GCA and 43 controls were analyzed. The mean pERM intensity score in non-GCA subjects was 3.9 – 1.4 (compared to 5.0 – 1.4 in those with GCA, p = 0.002). Using the predetermined cut-off of 4 to define high pERM intensity, subjects with GCA were significantly more likely to have a high pERM intensity score compared to non-GCA, OR 3.67, 95%CI :1.19,11.36; p= 0.019. The sensitivity of high pERM intensity score for diagnosis of GCA in histologically negative TAB was 86%, 95%CI: 70,95.

Conclusion

In this well-characterized cohort, those with biopsy-negative GCA had significantly higher pERM intensity scores compared to subjects without GCA. pERM staining has diagnostic significance in enhancing the sensitivity of TAB, and may help to define the clinically important group of biopsynegative GCA.

Rho GTPase signaling in rheumatic diseases

Rho guanosine triphosphatase (GTPases), as molecular switches, have been identified to be dysregulated and involved in the pathogenesis of various rheumatic diseases, mainly including rheumatoid arthritis, osteoarthritis, systemic sclerosis, and systemic lupus erythematosus. Downstream pathways involving multiple types of cells, such as fibroblasts, chondrocytes, synoviocytes, and immunocytes are mediated by activated Rho GTPases to promote pathogenesis. Targeted therapy via inhibitors of Rho GTPases has been implicated in the treatment of rheumatic diseases, demonstrating promising effects. In this review, the effects of Rho GTPases in the pathogenesis of rheumatic diseases are summarized, and the Rho GTPase-mediated pathways are elucidated. Therapeutic strategies using Rho GTPase inhibitors in rheumatic diseases are also discussed to provide insights for further exploration of targeted therapy in preclinical studies and clinical practice. Future directions on studies of Rho GTPases in rheumatic diseases based on current understandings are provided.

Rho GTPases in kidney physiology and diseases

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

Insight Into Rho Kinase Isoforms in Obesity and Energy Homeostasis

Obesity and associated complications increasingly jeopardize global health and contribute to the rapidly rising prevalence of type 2 diabetes mellitus and obesity-related diseases. Developing novel methods for the prevention and treatment of excess body adipose tissue expansion can make a significant contribution to public health. Rho kinase is a Rho-associated coiled-coil-containing protein kinase (Rho kinase or ROCK). The ROCK family including ROCK1 and ROCK2 has recently emerged as a potential therapeutic target for the treatment of metabolic disorders. Up-regulated ROCK activity has been involved in the pathogenesis of all aspects of metabolic syndrome including obesity, insulin resistance, dyslipidemia and hypertension. The RhoA/ROCK-mediated actin cytoskeleton dynamics have been implicated in both white and beige adipogenesis. Studies using ROCK pan-inhibitors in animal models of obesity, diabetes, and associated complications have demonstrated beneficial outcomes. Studies via genetically modified animal models further established isoform-specific roles of ROCK in the pathogenesis of metabolic disorders including obesity. However, most reported studies have been focused on ROCK1 activity during the past decade. Due to the progress in developing ROCK2-selective inhibitors in recent years, a growing body of evidence indicates more attention should be devoted towards understanding ROCK2 isoform function in metabolism. Hence, studying individual ROCK isoforms to reveal their specific roles and principal mechanisms in white and beige adipogenesis, insulin sensitivity, energy balancing regulation, and obesity development will facilitate significant breakthroughs for systemic treatment with isoform-selective inhibitors. In this review, we give an overview of ROCK functions in the pathogenesis of obesity and insulin resistance with a particular focus on the current understanding of ROCK isoform signaling in white and beige adipogenesis, obesity and thermogenesis in adipose tissue and other major metabolic organs involved in energy homeostasis regulation.

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

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

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.

TFH cells in systemic sclerosis

Systemic sclerosis is an autoimmune disease characterized by excessive dermal fibrosis with progression to internal organs, vascular impairment and immune dysregulation evidenced by the infiltration of inflammatory cells in affected tissues and the production of auto antibodies. While the pathogenesis remains unclear, several data highlight that T and B cells deregulation is implicated in the disease pathogenesis. Over the last decade, aberrant responses of circulating T follicular helper cells, a subset of CD4 T cells which are able to localise predominantly in the B cell follicles through a high level of chemokine receptor CXCR5 expression are described in pathogenesis of several autoimmune diseases and chronic graft-versus-host-disease. In the present review, we summarized the observed alteration of number and frequency of circulating T follicular helper cells in systemic sclerosis. We described their role in aberrant B cell activation and differentiation though interleukine-21 secretion. We also clarified T follicular helper-like cells involvement in fibrogenesis in both human and mouse model. Finally, because T follicular helper cells are involved in both fibrosis and autoimmune abnormalities in systemic sclerosis patients, we presented the different strategies could be used to target T follicular helper cells in systemic sclerosis, the therapeutic trials currently being carried out and the future perspectives from other auto-immune diseases and graft-versus-host-disease models.

Protein-Activated Kinase 3 (PAK3)-Related Intellectual Disability Associated with Combined Immunodeficiency: A Case Report

BACKGROUND X-linked intellectual disabilities constitute a group of clinically and genetically heterogeneous disorders that are divided into syndromic and nonsyndromic forms. PAK3 mutations are associated with X-linked nonsyndromic forms of intellectual disability, with the most common clinical features being cognitive deficit, large ears, oral motor hypotonia, and neurobehavioral abnormalities. These mutations have been reported to be associated with either loss of the PAK3 protein or loss of its kinase activity. We report a case with the novel PAK3 variant c.685C>T p.(Pro229Ser), which has not been previously described. CASE REPORT We report the first case of a PAK3 mutation to present with the common clinical features along with immunodeficiency resembling common variable immune deficiency. Our patient was a 10-year-old girl who had experienced septic shock with a rapidly deteriorating course when she was 5-years-old. The initial immune work-up showed lymphopenia affecting all cell lines, but preferentially the B-cell compartment. Further work-up of this patient revealed low levels of immunoglobulin (Ig) G, undetectable IgA, reduced IgG1 and IgG2 subclasses, and poor response to the diphtheria/tetanus vaccine. Lymphocyte function, tested as the response to the mitogen phytohemagglutinin, was low and fluctuated between 9% and 22% compared with control samples. The patient experienced recurrent respiratory tract infections, and she responded well to regular intravenous Ig treatment and antibiotic prophylaxis. CONCLUSIONS The current case might provide a new insight into PAK3 gene function. Although further evidence is needed, it is worth considering that immunological abnormalities may be associated with PAK3 gene mutations.

Splicing factor SRSF1 limits IFN-γ production via RhoH and ameliorates experimental nephritis

OBJECTIVE

CD4 T helper 1 (Th1) cells producing IFN-γ contribute to inflammatory responses in the pathogenesis of SLE and lupus nephritis. Moreover, elevated serum type II IFN levels precede the appearance of type I IFNs and autoantibodies in patient years before clinical diagnosis. However, the molecules and mechanisms that control this inflammatory response in SLE remain unclear. Serine/arginine-rich splicing factor 1 (SRSF1) is decreased in T cells from SLE patients, and restrains T cell hyperactivity and systemic autoimmunity. Our objective here was to evaluate the role of SRSF1 in IFN-γ production, Th1 differentiation and experimental nephritis.

METHODS

T cell-conditional Srsf1-knockout mice were used to study nephrotoxic serum-induced nephritis and evaluate IFN-γ production and Th1 differentiation by flow cytometry. RNA sequencing was used to assess transcriptomics profiles. RhoH was silenced by siRNA transfections in human T cells by electroporation. RhoH and SRSF1 protein levels were assessed by immunoblots.

RESULTS

Deletion of Srsf1 in T cells led to increased Th1 differentiation and exacerbated nephrotoxic serum nephritis. The expression levels of RhoH are decreased in Srsf1-deficient T cells, and silencing RhoH in human T cells leads to increased production of IFN-γ. Furthermore, RhoH expression was decreased and directly correlated with SRSF1 in T cells from SLE patients.

CONCLUSION

Our study uncovers a previously unrecognized role of SRSF1 in restraining IFN-γ production and Th1 differentiation through the control of RhoH. Reduced expression of SRSF1 may contribute to pathogenesis of autoimmune-related nephritis through these molecular mechanisms.

Rho kinase Blockade Ameliorates DSS-Induced Ulcerative Colitis in Mice Through Dual Inhibition of the NF-κB and IL-6/STAT3 Pathways

Inflammatory bowel disease (IBD) has received much attention due to its increasing worldwide incidence and potential increased risk of colorectal cancer. The protective function of a Rho-associated protein kinase inhibitor (Y-27632) against 2,4,6-trinitrobenzene sulfonic acid (TNBS) induced mouse colitis has been proven in previous studies, but the concrete therapeutic mechanism of Y-27632 is still not completely illuminated. This current research is intended for further investigation of the effect and mechanism of Y-27632 in a mouse model of acute experimental ulcerative colitis induced by dextran sulfate sodium (DSS). A total of 24 male BALB/c mice were randomly separated into the following three groups (n = 8 per group) and injected intraperitoneally with the corresponding reagents for 7 days: control group (PBS), DSS group (PBS), and Y-27632 group (PBS and Y-27632; 10 mg/kg). Our data indicated that Y-27632 could significantly improve the severity of colitis, as evidenced by the disease activity index (DAI) scores, histological damage, and colon length. Additionally, Y-27632 treatment significantly decreased CD68 and proinflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-17F (IL-17F), and interleukin-6 (IL-6). Furthermore, Y-27632 potently and pleiotropically suppressed nuclear factor-κB (NF-κB) and signal transduction and transcriptional activator 3 (STAT3) activation as well as the activity of prosurvival genes that are dependent on these transcription factors. In summary, the study demonstrates that Y-27632 exerts ameliorative effects on colonic inflammation mediated through dual inhibition of the NF-κB and IL-6/STAT3 pathways and thus is likely to function as a prospective novel treatment for human ulcerative colitis (UC).

Current Insights and Future Prospects for Targeting IL-17 to Treat Patients With Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by immune cell abnormalities which lead to the production of autoantibodies and the deposition of immune complexes. Interleukin (IL)-17-producing cells play an important role in the pathogenesis of the disease, making them an attractive therapeutic target. Studies in lupus-prone mice and of ex vivo cells from patients with SLE humans have shown that IL-17 represents a promising therapeutic target. Here we review molecular mechanisms involved in IL-17 production and Th17 cell differentiation and function and an update on the role of IL-17 in autoimmune diseases and the expected usefulness for targeting IL-17 therapeutically.

Long Non-Coding RNA PCAT6 Induces M2 Polarization of Macrophages in Cholangiocarcinoma via Modulating miR-326 and RhoA-ROCK Signaling Pathway

LncRNAs can act crucial roles in multiple tumors including cholangiocarcinoma (CCA). M2 polarization of macrophages is crucial for their biological roles in immunologic tolerance, which is able to induce tumorigenesis. Given that increasing evidence have suggested that lncRNAs could participate in modulating immune cell differentiation and function. Our current study was aimed to identify the underlying mechanism of lncRNA prostate cancer-associated transcript 6 (PCAT6) in CCA progression via regulating M2 macrophage polarization. PCAT6 has been reported as an oncogene in many cancers. In our work, we observed increased expression of PCAT6 in CCA patients. PCAT6 expression in various types of immune cells derived from CCA patients was tested by quantitative real-time PCR (qRT-PCR). It was revealed that PCAT6 was highly expressed in macrophages, which indicated that PCAT6 might regulate the function of macrophages to promote CCA progression. Then, via establishing CCA xenograft mouse model, we found loss of PCAT6 obviously triggered the immune response and reduced the in vivo tumor growth. In addition, overexpression of PCAT6 led to the M2 polarization of THP-1-differentiated macrophages. Moreover, miR-326 was predicted and proved as a target for PCAT6. In addition, down-regulation of PCAT6 repressed M2 polarization of macrophages, which was reversed by miR-326 inhibitors. The increase of PCAT6 induced the accumulation of ROS, mitochondrial and metabolic dysfunction in macrophages and mimics of miR-326 exhibited an opposite process. RohA has been recognized as a significant regulator of immune cell function. In our current work, we observed that RohA function as a downstream target for miR-326. In conclusion, our study highlighted a significant role of PCAT6/miR-326/RohA in immune response of macrophages in CCA and indicated PCAT6 as a potential target of immunotherapy in CCA.

Inhibition of ROCK2 alleviates renal fibrosis and the metabolic disorders in the proximal tubular epithelial cells

Non-specific inhibition of Rho-associated kinases (ROCKs) alleviated renal fibrosis in the unilateral ureteral obstruction (UUO) model, while genetic deletion of ROCK1 did not affect renal pathology in mice. Thus, whether ROCK2 plays a role in renal tubulointerstitial fibrosis needs to be clarified. In the present study, a selective inhibitor against ROCK2 or genetic approach was used to investigate the role of ROCK2 in renal tubulointerstitial fibrosis. In the fibrotic kidneys of chronic kidney diseases (CKDs) patients, we observed an enhanced expression of ROCK2 with a positive correlation with interstitial fibrosis. In mice, the ROCK2 protein level was time-dependently increased in the UUO model. By treating CKD animals with KD025 at the dosage of 50 mg/kg/day via intraperitoneal injection, the renal fibrosis shown by Masson's trichrome staining was significantly alleviated along with the reduced expression of fibrotic genes. In vitro, inhibiting ROCK2 by KD025 or ROCK2 knockdown/knockout significantly blunted the pro-fibrotic response in transforming growth factor-β1 (TGF-β1)-stimulated mouse renal proximal tubular epithelial cells (mPTCs). Moreover, impaired cellular metabolism was reported as a crucial pathogenic factor in CKD. By metabolomics analysis, we found that KD025 restored the metabolic disturbance, including the impaired glutathione metabolism in TGF-β1-stimulated tubular epithelial cells. Consistently, KD025 increased antioxidative stress enzymes and nuclear erythroid 2-related factor 2 (Nrf2) in fibrotic models. In addition, KD025 decreased the infiltration of macrophages and inflammatory response in fibrotic kidneys and blunted the activation of macrophages in vitro. In conclusion, inhibition of ROCK2 may serve as a potential novel therapy for renal tubulointerstitial fibrosis in CKD.

KD025, an anti-adipocyte differentiation drug, enhances the efficacy of conventional chemotherapeutic drugs in ABCG2-overexpressing leukemia cells

Most patients with advanced leukemia eventually die from multidrug resistance (MDR). Chemotherapy-resistant leukemia cells may lead to treatment failure and disease relapse. Overexpression of ATP-binding cassette subfamily G member 2 (ABCG2) leads to MDR, which serves as a potential biomarker and target of therapeutic intervention for leukemia cells. Targeting ABCG2 is a potential strategy for selective therapy and eradicate MDR cells, thus improving malignant leukemia treatment. KD025 (SLx-2119) is a novel Rho-associated protein kinase 2-selective inhibitor, which has been shown to inhibit adipogenesis in human adipose-derived stem cells and restore impaired immune homeostasis in autoimmunity therapy. The present study demonstrated that KD025 improved the efficacy of antineoplastic drugs in ABCG2-overexpressing leukemia cells and primary leukemia blast cells derived from patients with leukemia. Moreover, KD025 significantly inhibited the efflux of [³H]-mitoxantrone and hence accumulated higher levels of [³H]-mitoxantrone in HL60/ABCG2 cells. However, mechanistic research indicated that KD025 did not alter the protein levels and subcellular locations of ABCG2. KD025 may restrain the efflux activity of ABCG2 by obstructing ATPase activity. Taken together, KD025 can sensitize conventional antineoplastic drugs in ABCG2-overexpressing leukemia cells by blocking the pump function of ABCG2 protein. The present findings may provide a novel and useful combinational therapeutic strategy of KD025 and antineoplastic drugs for leukemia patients with ABCG2-mediated MDR.

Statins and autoimmunity: State-of-the-art

HMG-CoA reductase inhibitors, or statins, are potent plasma LDL-cholesterol (LDL-c) lowering agents. Since the introduction of the first statin, lovastatin, in 1987, accumulating evidence showed that non-cholesterol lowering effects play an important role in their efficacy to reduce atherosclerotic cardiovascular disease (ASCVD). Thus, these non-LDL-c lowering properties could benefit patients with immune-mediated diseases. Statins and their associated immune-modulating roles have recently received much attention. Different statins have been administered in various experimental and clinical studies focused on autoimmunity. The results indicate that statins can modulate immune responses through mevalonate pathway-dependent and -independent mechanisms. The anti-inflammatory and immune-modulating effects include cell adhesion, migration of antigen presenting cells, and differentiation, as well as activation, of T-cells. In various autoimmune diseases (e.g. rheumatoid arthritis, lupus, and multiple sclerosis), promising results have been obtained to date.

Coptisine Alleviates Pristane-Induced Lupus-Like Disease and Associated Kidney and Cardiovascular Complications in Mice

Systemic lupus erythaematosus (SLE) is a chronic multi-system autoimmune disease with a high prevalence of kidney and cardiovascular complications. Considering that Rho-associated coiled-coil-containing protein kinases (ROCKs) play important roles in SLE, inflammation, and cardiovascular disease, we hypothesized that coptisine, which has been found to inhibit ROCKs, may have an effect on SLE. The effect of coptisine was assessed in female BALB/c mice intraperitoneally injected with 0.5 mL of pristane. Serum autoantibodies were tested every month, blood pressure was measured every 2 months, and serum inflammatory markers, spleen pathologic characteristics, renal injury and vascular function were observed at 6 months. The results showed that coptisine decreased the levels of serum autoantibodies and serum inflammatory markers in the SLE mice, improved the pathologic characteristics of the spleen, and simultaneously improved renal injury, decreased inflammatory responses in the kidneys, reduced blood pressure, and improved vascular endothelial function. Western blot assays revealed that inhibiting the activation of the NF-κB and Rho/ROCK signalling pathways and downstream signalling molecules might be the potential mechanisms of the effects of coptisine. Our findings suggest that therapy with coptisine may be a strategy for preventing SLE and ameliorating associated kidney and cardiovascular complications.

LncRNA-SMILR modulates RhoA/ROCK signaling by targeting miR-141 to regulate vascular remodeling in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a fatal progressive disease characterized by an increased blood pressure in the pulmonary arteries. RhoA/Rho-kinase (RhoA/ROCK) signaling activation is often associated with PAH. The purpose of this study is to investigate the role and mechanisms of long noncoding RNA (lncRNA) smooth muscle-induced lncRNA (SMILR) to activate the RhoA/ROCK pathway in PAH. SMILR, microRNA-141 (miR-141), and RhoA were identified by qRT-PCR in PAH patients' serum. 3-(4,5-Dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT), wound-healing assay, cell counting kit-8 (CCK-8) assay, and flow cytometry were performed to determine cell viability, migration, proliferation, and cell cycle in human pulmonary arterial smooth muscle cells (hPASMCs) and primary PASMCs from PAH patients. We also performed bioinformatical prediction, luciferase reporter assay, and RNA-binding protein immunoprecipitation (RIP) to assess the interaction among SMILR, miR-141, and RhoA. The RhoA/ROCK pathway and proliferation-related proteins were measured by Western blotting. Finally, we introduced the small hairpin (sh)SMILR to monocrotaline-induced PAH rat model and used the hemodynamic measurement, qRT-PCR, and immunohistochemistry to examine the therapeutic effects of shSMILR. SMILR and RhoA expression were upregulated, while miR-141 expression was downregulated in PAH patients. SMILR directly interacted with miR-141 and negatively regulated its expression. Knockdown of SMILR suppressed PASMC proliferation and migration induced by hypoxia. Furthermore, overexpression of miR-141 could inhibit the RhoA/ROCK pathway by binding to RhoA, thereby repressing cell proliferation-related signals. Knockdown of SMILR significantly inhibited the Rho/ROCK activation and vascular remodeling in monocrotaline-induced rats. Knockdown of SMILR effectively elevated miR-141 expression and in turn inhibited the RhoA/ROCK pathway to regulate vascular remodeling and reduce blood pressure in PAH.NEW & NOTEWORTHY Smooth muscle enriched long noncoding RNA (SMILR), as a long noncoding RNA (lncRNA), was increased in pulmonary arterial hypertension (PAH) patients and in vitro and in vivo models. SMILR activated RhoA/ROCK signaling by targeting miR-141 to disinhibit its downstream target RhoA. SMILR knockdown or miR-141 overexpression inhibited hypoxia-induced cell proliferation and migration via repressing RhoA/ROCK signaling in pulmonary arterial smooth muscle cells (PASMCs), which was confirmed in vivo experiments that knockdown of SMILR inhibited vascular remodeling and alleviated PAH in rats. SMILR may be a promising and novel therapeutic target for the treatment and drug development of PAH.

Determination of KD025 (SLx-2119), a Selective ROCK2 Inhibitor, in Rat Plasma by High-Performance Liquid Chromatography-Tandem Mass Spectrometry and its Pharmacokinetic Application

KD025 (SLx-2119), the first specific Rho-associated protein kinase 2 (ROCK2) inhibitor, is a potential new drug candidate currently undergoing several phase 2 clinical trials for psoriasis, idiopathic pulmonary fibrosis, chronic graft-versus-host disease, and systemic sclerosis. In this study, a bio-analytical method was developed and fully validated for the quantification of KD025 in rat plasma and for application in pharmacokinetic studies. KD025 and GSK429286A (the internal standard) in rat plasma samples were analyzed by high-performance liquid chromatography-tandem mass spectrometry with m/z transition values of 453.10 → 366.10 and 433.00 → 178.00, respectively. The method was fully validated according to the United State Food and Drug Administration guidelines in terms of selectivity, linearity, accuracy, precision, sensitivity, matrix effects, extraction recovery, and stability. The method enabled the quantification of KD025 levels in rat plasma following oral administration of 5 mg/kg KD025 and intravenous administration of 2 mg/kg KD025 to rats, respectively. Our findings suggest that the developed method is practical and reliable for pharmacokinetic studies of KD025 in preclinical animals.

Beneficial role of simvastatin in experimental autoimmune myositis

OBJECTIVE

Statins have immunomodulatory potential in autoimmune diseases but had not been studied as a disease-modifying agent in inflammatory myopathies. The objective of this study is to assess the effect of simvastatin in an experimental model of autoimmune myositis in mice on muscle strength and histopathology.

METHODS

Four groups of mice (n = 5 per group) were selected for experimentally induced myositis. Mice were immunized with 1.5 mg myosin in complete Freund's adjuvant weekly for two times and injected with 500 ng pertussis toxin twice immediately after each immunization. From day 1 before immunization to 10 days after the last immunization, mice were treated with oral simvastatin (10 or 20 or 40 mg/kg) diluted in DMSO. The control group mice were injected with complete Freund's adjuvant weekly for two times and did not receive treatment. Non-immunized mice (n = 5 per group) were treated either with simvastatin (5 mg/kg or 20 mg/kg or 40 mg/kg of simvastatin diluted in DMSO) or with DMSO.

RESULTS

Inflammation was observed in myositis groups with positive myositis-specific antibodies. Muscle strength dropped significantly after immunization. Immunized simvastatin 20 mg/kg treated group had significantly higher muscle strength versus non-treated myositis mice and versus other simvastatin doses. Besides, a trend toward higher serum Th17 percentage population was found in immunized non-treated mice, versus immunized simvastatin- treated mice, without significant difference.

CONCLUSION

Simvastatin at 20 mg/kg decreases the severity of myositis in experimental autoimmune myositis and is a candidate of being a disease-modifying agent in inflammatory myopathies.

Elevated Circulating Interleukin-17 Levels in Patients with Systemic Lupus Erythematosus: A Meta-analysis

BACKGROUND

Previous studies concerning the circulating interleukin-17 (IL-17) in systemic lupus erythematosus (SLE) were contradictory.

AIMS

To further precisely investigate circulating IL-17 in SLE and evaluate its influential factors by meta-analysis.

METHODS

EMBASE, PubMed and Cochrane Library were comprehensively searched to obtain studies on circulating IL-17 in SLE patients by November 22, 2018. The results were illustrated by pooled standard mean difference (SMD) with corresponding 95% confidence interval (CI) using random-effects model as there was significant heterogeneity, which was estimated using Cochran Q and I² statistics. Subgroup analyses and sensitivity analyses were also conducted.

RESULTS

Overall, 1872 articles were reviewed and 20 studies involving 1067 subjects with SLE and 721 healthy controls (HCs) were enrolled in the final analysis according to inclusion criteria. Compared with HCs, circulating IL-17 levels in SLE patients were elevated (SMD: 1.183, 95% CI: 0.763-1.603; P < .001). Moreover, in comparison to HCs, European and Asian SLE patients, age <30 years, disease duration ≥5 years, NOS scores <7 and using ELISA showed increased circulating IL-17 status, whereas no significant change was observed in other subgroups. There was no significant publication bias. Sensitivity analyses demonstrated that the results of our meta-analysis were robust.

CONCLUSIONS

SLE patients have higher circulating IL-17 levels, which is influenced by ethnic, age and disease duration, literature quality and measurements.

Cardiovascular risk stratification and appropriate use of statins in patients with systemic lupus erythematosus according to different strategies

INTRODUCTION/OBJECTIVES

Cardiovascular risk management of patients with systemic lupus erythematosus (SLE) is medically relevant. The objectives were to estimate the cardiovascular risk by different strategies in patients with SLE, analyzing which proportion of patients would be candidates to receive statin therapy, and identify how many patients with statin indication received such drugs.

METHOD

A cross-sectional study was performed from a secondary database. Following the recommendations of National Institute for Health and Care Excellence (NICE) guidelines and the Argentine Consensus, the QRISK-3 and the adjusted Framingham (multiplying factor × 2) scores were calculated in primary prevention subjects. The indications for statin therapy according to these recommendations were analyzed.

RESULTS

In total, 110 patients were included. Regarding patients without previous cardiovascular history, the median adjusted Framingham score was 12.8% (4.1-21.9), and 45.2%, 22.6%, and 32.2% of them were classified at low, moderate, or high risk. The median QRISK-3 score was 6.0% (2.1-14.1) and 42.1% of subjects were classified "at risk". Only 60% of subjects in secondary prevention received statins, although no patient received the recommended doses. Analyzing patients in primary prevention who did not receive statins (87%), 43.4% and 45.2% of the patients were eligible for statin therapy according to NICE guidelines and Argentine Consensus, respectively.

CONCLUSIONS

Our findings showed that a large proportion of patients with SLE have a considerable cardiovascular risk and many of them would be eligible for statin therapy. However, the statin use observed was low.Key Points• A large proportion of patients with lupus have a considerable cardiovascular risk, explained in part by dyslipidemia.• Many patients with SLE would be eligible for statin therapy according to risk stratification based on conventional risk factors.• The use of statins in this population is inadequate.

Rho-kinase pathway activation and apoptosis in circulating leucocytes in patients with heart failure with reduced ejection fraction

Background

Increased Rho‐kinase activity in circulating leucocytes is observed in heart failure with reduced ejection fraction (HFrEF). However, there is little information in HFrEF regarding other Rho‐kinase pathway components an on the relationship between Rho‐kinase and apoptosis. Here, Rho‐kinase activation levels and phosphorylation of major downstream molecules and apoptosis levels were measured for the first time both in HFrEF patients and healthy individuals.

Methods

Cross‐sectional study comparing HFrEF patients (n = 20) and healthy controls (n = 19). Rho‐kinase activity in circulating leucocytes (peripheral blood mononuclear cells, PBMCs) was determined by myosin light chain phosphatase 1 (MYPT1) and ezrin‐radixin‐moesin (ERM) phosphorylation. Rho‐kinase cascade proteins phosphorylation p38‐MAPK, myosin light chain‐2, JAK and JNK were also analysed along with apoptosis.

Results

MYPT1 and ERM phosphorylation were significantly elevated in HFrEF patients, (3.9‐ and 4.8‐fold higher than in controls, respectively). JAK phosphorylation was significantly increased by 300% over controls. Phosphorylation of downstream molecules p38‐MAPK and myosin light chain‐2 was significantly higher by 360% and 490%, respectively, while JNK phosphorylation was reduced by 60%. Catecholamine and angiotensin II levels were significantly higher in HFrEF patients, while angiotensin‐(1‐9) levels were lower. Apoptosis in circulating leucocytes was significantly increased in HFrEF patients by 2.8‐fold compared with controls and significantly correlated with Rho‐kinase activation.

Conclusion

Rho‐kinase pathway is activated in PMBCs from HFrEF patients despite optimal treatment, and it is closely associated with neurohormonal activation and with apoptosis. ROCK cascade inhibition might induce clinical benefits in HFrEF patients, and its assessment in PMBCs could be useful to evaluate reverse remodelling and disease regression.

Leptin: an unappreciated key player in SLE

Leptin is the forerunner of the adipokine superfamily and plays a key role in regulating energy expenditure and neuroendocrine function. Researches into leptin put emphasize not only on the metabolic role but also its immunoregulatory effect on immune response through immunocyte activation and cytokine secretion. Leptin acts on receptors that are widespread throughout the body and that are expressed across many tissue types. As a consequence, the abnormal expression of leptin has been found to correlate with a number of diseases, including cancers, autoimmune diseases, and cardiovascular diseases. The significance of leptin in the development of autoimmune diseases is becoming increasingly prominent. Systemic lupus erythematosus (SLE) is a severe atypical autoimmune disease that causes damage to multiple organ systems. It is characterised by the following: impaired clearance of apoptotic cells, loss of tolerance to self-antigens, aberrant activation of T cells and B cells, and chronic inflammation. The heightened immunocyte response in SLE means that these physiological systems are particularly vulnerable to regulation by leptin in addition to being of great significance to the research field. Our current review provides insight into the regulatory roles that leptin plays on immune effector cells in SLE.

Inhibition of Rho-Kinase Downregulates Th17 Cells and Ameliorates Hepatic Fibrosis by Schistosoma japonicum Infection

BACKGROUND

Schistosomiasis is an immunopathogenic disease in which Th17 cells play vital roles. Hepatic granuloma formation and subsequent fibrosis are its main pathologic manifestations and the leading causes of hepatic cirrhosis, and effective therapeutic interventions are lacking. In this study, we explored the effects of fasudil, a selective RhoA-Rho-associated kinase (ROCK) inhibitor, on Th17 cells and the pathogenesis of schistosomiasis.

METHODS

Mice were infected with Schistosoma japonicum and treated with fasudil. The worm burden, hepatic granuloma formation, and fibrosis were evaluated. The roles of fasudil on Th17, Treg, and hepatic stellate cells were analyzed.

RESULTS

Fasudil therapy markedly reduced the granuloma size and collagen deposit in livers from mice infected with S. japonicum. However, fasudil therapy did not affect the worm burden in infected mice. The underlying cellular and molecular mechanisms were investigated. Fasudil suppressed the activation and induced the apoptosis of CD4⁺ T cells. Fasudil inhibited the differentiation and effector cytokine secretion of Th17 cells, whereas it upregulated Treg cells in vitro. It also restrained the in vivo interleukin (IL)-4 and IL-17 levels in infected mice. Fasudil directly induced the apoptosis of hepatic stellate cells and downregulated the expressions of hepatic fibrogenic genes, such as collagen type I (Col-I), Col-III, and transforming growth factor-1 (TGF-β1). These effects may contribute to its anti-pathogenic roles in schistosomiasis.

CONCLUSIONS

Fasudil inhibits hepatic granuloma formation and fibrosis with downregulation of Th17 cells. Fasudil might serve as a novel therapeutic agent for hepatic fibrosis due to schistosome infections and perhaps other disorders.

The Involvement of the RhoA/ROCK Signaling Pathway in Hypersensitivity Reactions Induced by Paclitaxel Injection

A high incidence of hypersensitivity reactions (HSRs) largely limits the use of paclitaxel injection. Currently, these reactions are considered to be mediated by histamine release and complement activation. However, the evidence is insufficient and the molecular mechanism involved in paclitaxel injection-induced HSRs is still incompletely understood. In this study, a mice model mimicking vascular hyperpermeability was applied. The vascular leakage induced merely by excipients (polyoxyl 35 castor oil) was equivalent to the reactions evoked by paclitaxel injection under the same conditions. Treatment with paclitaxel injection could cause rapid histamine release. The vascular exudation was dramatically inhibited by pretreatment with a histamine antagonist. No significant change in paclitaxel injection-induced HSRs was observed in complement-deficient and complement-depleted mice. The RhoA/ROCK signaling pathway was activated by paclitaxel injection. Moreover, the ROCK inhibitor showed a protective effect on vascular leakage in the ears and on inflammation in the lungs. In conclusion, this study provided a suitable mice model for investigating the HSRs characterized by vascular hyperpermeability and confirmed the main sensitization of excipients in paclitaxel injection. Histamine release and RhoA/ROCK pathway activation, rather than complement activation, played an important role in paclitaxel injection-induced HSRs. Furthermore, the ROCK inhibitor may provide a potential preventive approach for paclitaxel injection side effects.

ROCK Inhibition Drives Resolution of Acute Inflammation by Enhancing Neutrophil Apoptosis

Uncontrolled inflammation leads to tissue damage and it is central for the development of chronic inflammatory diseases and autoimmunity. An acute inflammatory response is finely regulated by the action of anti-inflammatory and pro-resolutive mediators, culminating in the resolution of inflammation and restoration of homeostasis. There are few studies investigating intracellular signaling pathways associated with the resolution of inflammation. Here, we investigate the role of Rho-associated kinase (ROCK), a serine/threonine kinase, in a model of self-resolving neutrophilic inflammatory. We show that ROCK activity, evaluated by P-MYPT-1 kinetics, was higher during the peak of lipopolysaccharide-induced neutrophil influx in the pleural cavity of mice. ROCK inhibition by treatment with Y-27632 decreased the accumulation of neutrophils in the pleural cavity and was associated with an increase in apoptotic events and efferocytosis, as evaluated by an in vivo assay. In a model of gout, treatment with Y-27632 reduced neutrophil accumulation, IL-1β levels and hypernociception in the joint. These were associated with reduced MYPT and IκBα phosphorylation levels and increased apoptosis. Finally, inhibition of ROCK activity also induced apoptosis in human neutrophils and destabilized cytoskeleton, extending the observed effects to human cells. Taken together, these data show that inhibition of the ROCK pathway might represent a potential therapeutic target for neutrophilic inflammatory diseases.

RhoA as a Key Regulator of Innate and Adaptive Immunity

RhoA is a ubiquitously expressed cytoplasmic protein that belongs to the family of small GTPases. RhoA acts as a molecular switch that is activated in response to binding of chemokines, cytokines, and growth factors, and via mDia and the ROCK signaling cascade regulates the activation of cytoskeletal proteins, and other factors. This review aims to summarize our current knowledge on the role of RhoA as a general key regulator of immune cell differentiation and function. The contribution of RhoA for the primary functions of innate immune cell types, namely neutrophils, macrophages, and conventional dendritic cells (DC) to (i) get activated by pathogen-derived and endogenous danger signals, (ii) migrate to sites of infection and inflammation, and (iii) internalize pathogens has been fairly established. In activated DC, which constitute the most potent antigen-presenting cells of the immune system, RhoA is also important for the presentation of pathogen-derived antigen and the formation of an immunological synapse between DC and antigen-specific T cells as a prerequisite to induce adaptive T cell responses. In T cells and B cells as the effector cells of the adaptive immune system Rho signaling is pivotal for activation and migration. More recently, mutations of Rho and Rho-modulating factors have been identified to predispose for autoimmune diseases and as causative for hematopoietic malignancies.

Ablation of RhoA impairs Th17 cell differentiation and alleviates house dust mite-triggered allergic airway inflammation

Asthma is a heterogeneous chronic airway inflammation in which Th2 and Th17 cells are key players in its pathogenesis. We have reported that RhoA of Rho GTPases orchestrated glycolysis for Th2 cell differentiation and allergic airway inflammation by the use of a conditional RhoA-deficient mouse line. However, the role of RhoA in Th17 cells remains to be elucidated. In this study, we investigated the effects of RhoA deficiency on Th17 cells in the context of ex vivo cell culture systems and an in vivo house dust mites (HDM)-induced allergic airway inflammation. We found that RhoA deficiency inhibited Th17 differentiation and effector cytokine secretion, which was associated with the downregulations of Stat3 and Rorγt, key Th17 transcription factors. Furthermore, loss of RhoA markedly suppressed Th17 and neutrophil-involved airway inflammation induced by HDM in mice. The infiltrating inflammatory cells in the lungs and bronchoalveolar lavage (BAL) fluids were dramatically reduced in conditional RhoA-deficient mice. Th17 as well as Th2 effector cytokines were suppressed in the airways at both protein and mRNA levels. Interestingly, Y16, a specific RhoA inhibitor, was able to recapitulate the most phenotypes of RhoA genetic deletion in Th17 differentiation and allergic airway inflammation. Our data demonstrate that RhoA is a key regulator of Th17 cell differentiation and function. RhoA might serve as a potential novel therapeutic target for asthma and other inflammatory disorders.

Immunoglobulin Binding Protein 1 as a Potential Urine Biomarker in Patients with Lupus Nephritis

We evaluated the role of immunoglobulin binding protein 1 (IGBP1), a phosphoprotein associated with the B cell receptor (BCR) complex, as a urine biomarker in lupus nephritis (LN). The IGBP1 concentrations in plasma and urine of patients with LN, systemic lupus erythematosus (SLE) without nephritis and healthy controls were estimated by ELISA. IGBP1 expression in the kidneys of LN patients and transplantation donors was detected by immunohistochemistry. Microarray-based global gene expression profile of HK-2 cells with IGBP1 knock-down and fluorescence-activated cell sorting (FACS) for intracellular IGBP1 expression in human peripheral blood mononuclear cells (PBMCs) was performed. Urine IGBP1 levels were elevated significantly in LN patients, and it correlated with the clinical activity indices (complement 3 (C3) level, anti-dsDNA antibodies titer, SLE Disease Activity Index-2000 (SLEDAI-2K) and histological activity index. IGBP1 expression was increased in LN patients as compared to the donors and was detected mainly in the tubules by histopathology. In microarray analysis, several genes related to SLE pathogenesis (PPME1, ROCK2, VTCN1, IL-17R, NEU1, HLA-DM, and PTX3) responded to siRNA-mediated IGBP1 silencing. In FACS, IGBP1 was expressed mainly in the CD14⁺ cells. The overall expression of IGBP1 in PBMCs was higher in LN patients as compared with that in SLE patients without nephritis. Conclusively, urinary IGBP1 may be a novel biomarker reflecting the clinical and histological activities in LN.

Inhibition of ROCK activity regulates the balance of Th1, Th17 and Treg cells in myasthenia gravis

Aberrant ROCK activation has been found in patients with several autoimmune diseases, but the role of ROCK in myasthenia gravis (MG) has not yet been clearly investigated. Here, we demonstrated that ROCK activity was significantly higher in peripheral blood mononuclear cells (PBMCs) from MG patients. ROCK inhibitor Fasudil down-regulated the proportions of Th1 and Th17 cells in PBMCs of MG patients in vitro. Intraperitoneal injection of Fasudil ameliorated the severity of experimental autoimmune myasthenia gravis (EAMG) rats and restored the balance of Th1/Th2/Th17/Treg subsets. Furthermore, Fasudil inhibited the proliferation of antigen-specific Th1 and Th17 cells, and inhibited CD4 + T cells differentiated into Th1 and Th17 through decreasing phosphorylated Stat1 and Stat3, but promoted Treg cell differentiation through increasing phosphorylated Stat5. We conclude that dysregulated ROCK activity may be involved in the pathogenic immune response of MG and inhibition of ROCK activity might serve as a novel treatment strategy for MG.

Emerging targets for the treatment of lupus erythematosus: There is no royal road to treating lupus

Systemic lupus erythematosus (SLE) is a highly heterogeneous autoimmune disease that preferentially affects women of child-bearing age. Most current treatments for SLE with the exception of belimumab are not target-specific. Nontargeted therapy such as corticosteroids, cyclophosphamide, and other immunosuppressive drugs results in unwanted adverse effects. Although progress in treatment, including supportive therapy, has dramatically improved the prognosis of patients with SLE, better treatment drugs and protocols with fewer adverse effects and higher efficacy for the most severe form of SLE are needed. Advancements in genomics, immunology, and pathophysiology in the field of systemic autoimmunity have provided physicians with increasing knowledge, but the most appropriate treatment for each patient with SLE remains to be established. Therefore, the search for novel treatment targets in patients with SLE is ongoing. This review focuses on recent findings in the genetics of lupus and the abnormalities in cellular interactions, cytokine profiles, and intracellular signaling in patients with SLE. Novel molecular targets for lupus, mostly introduced through clinical trials, are then discussed based on these findings.

The Potential Use of Metformin, Dipyridamole, N-Acetylcysteine and Statins as Adjunctive Therapy for Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a chronic inflammatory autoimmune condition that can potentially affect every single organ during the course of the disease, leading to increased morbidity and mortality, and reduced health-related quality of life. While curative treatment is currently non-existent for SLE, therapeutic agents such as glucocorticoids, mycophenolate, azathioprine, cyclosporine, cyclophosphamide and various biologics are the mainstay of treatment based on their immunomodulatory and immunosuppressive properties. As a result of global immunosuppression, the side-effect profile of the current therapeutic approach is unfavourable, with adverse effects including myelosuppression, infection and malignancies. Hydroxychloroquine, one of the very few Food and Drug Administration (FDA)-approved medications for the treatment of SLE, has been shown to offer a number of therapeutic benefits to SLE patients independent of its immunomodulatory effect. As such, it is worth exploring drugs similar to hydroxychloroquine that confer additional clinical benefits unrelated to immunosuppressive mechanisms. Indeed, apart from hydroxychloroquine, a number of studies have explored the use of a few conventionally non-immunosuppressive drugs that are potentially useful in the management of SLE. In this review, non-immunosuppressive therapeutic agents, namely metformin, dipyridamole, N-acetylcysteine and statins, will be critically discussed with regard to their mechanisms of action and efficacy pertaining to their potential therapeutic role in SLE.

The role of IL-17 in systemic lupus erythematosus and its potential as a therapeutic target

INTRODUCTION

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by autoantibodies production and immune complex deposition with systemic clinical manifestations. Interleukin (IL)-17-producing cells play a crucial role in disease pathogenesis and represent an attractive therapeutic target. Areas covered: This review provides an update on the possibility of targeting IL-17 in SLE. The rational for this approach as well as currently available and future targets are discussed. Expert opinion: Although human expression studies and animal models indicate that IL-17 blocking may be a promising therapeutic strategy for SLE, direct evidence for IL-17 inhibition in SLE patients is unavailable. Biologic therapies and small-molecule drugs that target IL-17 production are required for the achievement of a favorable clinical effect in SLE patients.

Clinical significance and immunobiology of IL-21 in autoimmunity

Interleukin-21 (IL-21), an autocrine cytokine predominantly produced by follicular helper T (Tfh) and T helper 17 (Th17) cells, has been proven to play an important role in the immune system, for example, by promoting proliferation and the development of Tfh and Th17 cells, balancing helper T cell subsets, inducing B cell generation and differentiation into plasma cells, and enhancing the production of immunoglobulin. These effects are mainly mediated by activation of the JAK/STAT, MAPK and PI3K pathways. Some IL-21 target genes, such as B lymphocyte induced maturation protein-1 (Blimp-1), suppressor of cytokine signaling (SOCS), CXCR5 and Bcl-6, play important roles in the immune response. Therefore, IL-21 has been linked to autoimmune diseases. Indeed, IL-21 levels are increased in the peripheral blood and tissues of patients with systematic lupus erythematosus (SLE), rheumatoid arthritis (RA), type 1 diabetes (T1D), immune thrombocytopenia (ITP), primary Sjogren's syndrome (pSS), autoimmune thyroid disease (AITD) and psoriasis. This increased IL-21 even positively associates with Tfh cells, plasma cells, autoantibodies and disease activity in SLE and RA. Additionally, IL-21 has been utilized as a therapeutic target in SLE, RA, T1D and psoriatic mouse models. Profoundly, clinical trials have shown safety and improvement in RA patients. However, tolerance and long-term pharmacodynamics effects with low bioavailability have been found in SLE patients. Therefore, this review aims to summarize the latest progress on IL-21 function and its signaling pathway and discuss the role of IL-21 in the pathogenesis of and therapy for autoimmune diseases, with the hope of providing potential therapeutic and diagnostic strategies for clinical use.

Recent developments in systemic lupus erythematosus pathogenesis and applications for therapy

PURPOSE OF REVIEW

Systemic lupus erythematosus (SLE) pathogenesis is complex. Aberrancies of immune function that previously were described but not well understood are now becoming better characterized, in part through recognition of monogenic cases of lupus-like disease.

RECENT FINDINGS

We highlight here recent descriptions of metabolic dysfunction, cytokine dysregulation, signaling defects, and DNA damage pathways in SLE. Specifically, we review the effects of signaling abnormalities in mammalian target of rapamycin, Rho kinase, Bruton's tyrosine kinase, and Ras pathways. The importance of DNA damage sensing and repair pathways, and their influence on the overproduction of type I interferon in SLE are also reviewed.

SUMMARY

Recent findings in SLE pathogenesis expand on previous understandings of broad immune dysfunction. These findings have clinical applications, as the dysregulated pathways described here can be targeted by existing and preclinical therapies.