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

Diagnostic value of ROCK2 protein in immune checkpoint inhibitors-associated myocarditis

BACKGROUND

Immune checkpoint inhibitors (ICIs) have advanced cancer treatment but are associated with serious cardiovascular side effects, including myocarditis, which is challenging to diagnose due to limited specificity of current biomarkers. Rho-associated kinase 2 (ROCK2) may play a role in myocarditis pathogenesis by mediating inflammation and myocardial remodeling. This study investigates the potential of ROCK2 protein detection as a diagnostic marker for ICIs-associated myocarditis.

OBJECTIVES

To evaluate ROCK2 protein levels in patients with ICIs-associated myocarditis and assess its diagnostic value, providing insights for improved identification and management of this condition.

METHODS

We conducted a study with 10 ICIs-treated gastric cancer patients diagnosed with myocarditis and a control group of 10 similar ICIs-treated patients without myocarditis. ROCK2 levels and inflammatory markers were measured via ELISA, and clinical assessments included cardiac imaging, electrocardiography, and echocardiography. Statistical analysis of group differences used independent t-tests and chi-square tests.

RESULTS

ROCK2 expression was significantly higher in myocarditis patients compared to controls (p < 0.001), alongside elevated inflammatory markers, specifically hypersensitive C-reactive protein (hs-CRP), interleukins1β (IL-1β) and IL-17. Diagnostic myocardial markers such as N-terminal pro B-type natriuretic peptide (NT-proBNP), and soluble suppression of tumorigenicity 2 (sST2) also showed substantial elevation. Following treatment discontinuation and glucocorticoid administration, both ROCK2 levels and inflammatory indicators declined.

CONCLUSIONS

Elevated ROCK2 protein levels could serve as a promising biomarker for ICIs-associated myocarditis. ROCK2 detection, combined with traditional markers, may enhance diagnostic accuracy. Further studies are warranted to explore ROCK2 inhibition as a potential therapeutic strategy for managing ICIs-associated myocarditis.

Radiation-induced lung injury: from mechanism to prognosis and drug therapy

Radiation induced lung injury, known as the main complication of thoracic radiation, remains to be a major resistance to tumor treatment. Based on the recent studies on radiation-induced lung injury, this review collated the possible mechanisms at the level of target cells and key pathways, corresponding prognostic models including predictors, patient size, number of centers, radiotherapy technology, construction methods and accuracy, and pharmacotherapy including drugs, targets, therapeutic effects, impact on anti-tumor treatment and research types. The research priorities and limitations are summarized to provide a reference for the research and management of radiation-induced lung injury.

Inhibition of Myocardin-related Transcription Factor A Ameliorates Pathological Remodeling of the Pressure-loaded Right Ventricle

Right ventricular (RV) fibrosis is associated with RV dysfunction in a variety of RV pressure-loading conditions in which RV mechanical stress is increased, but the underlying mechanisms driving RV fibrosis are incompletely understood. In pulmonary and cardiovascular diseases characterized by elevated mechanical stress and transforming growth factor-β1 signaling, myocardin-related transcription factor A (MRTF-A) is a mechanosensitive protein critical to driving myofibroblast transition and fibrosis. In this study, we investigated whether MRTF-A inhibition improves RV profibrotic remodeling and function in response to a pulmonary artery banding (PAB) model of RV pressure loading. Rats were assigned into either sham or PAB groups. MRTF-A inhibitor CCG-1423 was administered daily at 0.75 mg/kg in a subset of PAB animals. Echocardiography and pressure-volume hemodynamics were obtained at a terminal experiment 6 weeks later. RV myocardial samples were analyzed for fibrosis, cardiomyocyte hypertrophy, and profibrotic signaling. MRTF-A inhibition slightly reduced systolic dysfunction in PAB rats reflected by increased lateral tricuspid annulus peak systolic velocity, whereas diastolic function parameters were not significantly improved. RV remodeling was attenuated in PAB rats with MRTF-A inhibition, displaying reduced fibrosis. This was accompanied with a reduction in PAB-induced upregulation of Yes-associated protein (YAP) and its paralog transcriptional coactivator with PDZ-binding motif (TAZ). We also confirmed, using a second-generation MRTF-A inhibitor CCG-203971, that MRTF-A is critical in driving RV fibroblast expression of TAZ and markers of myofibroblast transition in response to transforming growth factor-β1 stress and RhoA activation. These studies identify RhoA, MRTF-A, and YAP/TAZ as interconnected regulators of profibrotic signaling in RV pressure loading and as potential targets to improve RV profibrotic remodeling.

Chronic Graft-versus-host Disease: Immune Insights, Therapeutic Advances, and Parallels for Solid Organ Transplantation

Chronic graft-versus-host disease remains a frequent and morbid outcome of allogeneic hematopoietic cell transplantation, in which the donor-derived immune system attacks healthy recipient tissue. Preceding tissue damage mediated by chemoradiotherapy and alloreactive T cells compromise central and peripheral tolerance mechanisms, leading to aberrant donor T cell and germinal center B cell differentiation, culminating in pathogenic macrophage infiltration and differentiation in a target tissue, with ensuant fibrosis. This process results in a heterogeneous clinical syndrome with significant morbidity and mortality, frequently requiring prolonged therapy. In this review, we discuss the processes that interrupt immune tolerance, the subsequent clinical manifestations, and new Food and Drug Administration-approved therapeutic approaches that have been born from a greater understanding of disease pathogenesis in preclinical systems, linking to parallel processes following solid organ transplantation.

Protease-activated receptor 2 deficient mice develop less angiotensin II induced left ventricular hypertrophy but more cardiac fibrosis

AIMS

Activation of Protease Activated Receptor 2 (PAR2) has been shown to be involved in regulation of injury-related processes including inflammation, fibrosis and hypertrophy. In this study we will investigate the role of PAR2 in cardiac injury in a mouse model of hypertension using continuous infusion with angiotensin II.

METHODS

Hypertension was induced in 12 weeks old wildtype (wt, n = 8) and PAR2 deficient mice (n = 9) by continuous infusion with angiotensin II for 4 weeks using osmotic minipumps. At the end, hearts were collected for analysis of left ventricular hypertrophy (LVH), myocardial capillary supply, fibrosis and localization of PAR2 expression using histological, immunohistological and mRNA expression analysis techniques. In addition, rat cardiac fibroblasts were treated with angiotensin II and PAR2 was inhibited by a blocking antibody and the PAR2 inhibitor AZ3451.

RESULTS

Cardiac PAR2 mRNA expression was downregulated by 40±20% in wt mice treated with AngII compared to untreated controls. Four weeks after AngII treatment, LVH was significantly increased in AngII-treated wt mice compared to similarly treated PAR2-deficient animals as determined by relative heart weight, left ventricular cross-sectional area, and analysis of ventricular lumen area determined on sections. Treatment of wt mice resulted in an approximately 3-fold increase in cardiac expression of FGF23, which was 50% lower in PAR2-deficient animals compared to wt animals and therefore no longer significantly different from expression levels in untreated control mice. In contrast, cardiac interstitial fibrosis was significantly higher in PAR2-deficient mice compared to similar treated wt controls, as assessed by Sirius Red staining (>3-fold) and collagen IV staining (>2-fold). Additional experiments with isolated cardiac fibroblasts showed induction of pro-fibrotic genes when treated with PAR2 inhibitors.

CONCLUSION

In angiotensin II-induced cardiac injury, PAR2 deficiency has an ambivalent effect, enhancing fibrosis on the one hand, but reducing LVH on the other.

The Extracellular Matrix and Cardiac Pressure Overload: Focus on Novel Treatment Targets

Heart failure is a significant health issue in developed countries, often stemming from conditions like hypertension, which imposes a pressure overload on the heart. Despite various treatment strategies for heart failure, many lack long-term effectiveness. A critical aspect of cardiac disease is the remodeling of the heart, where compensatory changes in the extracellular matrix exacerbate disease progression. This review explores the processes and changes occurring in the pressure-overloaded heart with respect to the extracellular matrix. It further summarizes current treatment strategies, and then focuses on novel treatment targets for maladaptive cardiac remodeling, derived from transverse aortic constriction-induced pressure overload animal models.

Fibroblast and myofibroblast activation in normal tissue repair and fibrosis

The term 'fibroblast' often serves as a catch-all for a diverse array of mesenchymal cells, including perivascular cells, stromal progenitor cells and bona fide fibroblasts. Although phenotypically similar, these subpopulations are functionally distinct, maintaining tissue integrity and serving as local progenitor reservoirs. In response to tissue injury, these cells undergo a dynamic fibroblast-myofibroblast transition, marked by extracellular matrix secretion and contraction of actomyosin-based stress fibres. Importantly, whereas transient activation into myofibroblasts aids in tissue repair, persistent activation triggers pathological fibrosis. In this Review, we discuss the roles of mechanical cues, such as tissue stiffness and strain, alongside cell signalling pathways and extracellular matrix ligands in modulating myofibroblast activation and survival. We also highlight the role of epigenetic modifications and myofibroblast memory in physiological and pathological processes. Finally, we discuss potential strategies for therapeutically interfering with these factors and the associated signal transduction pathways to improve the outcome of dysregulated healing.

Novel approaches to target fibroblast mechanotransduction in fibroproliferative diseases

The ability of cells to sense and respond to changes in mechanical environment is vital in conditions of organ injury when the architecture of normal tissues is disturbed or lost. Among the various cellular players that respond to injury, fibroblasts take center stage in re-establishing tissue integrity by secreting and organizing extracellular matrix into stabilizing scar tissue. Activation, activity, survival, and death of scar-forming fibroblasts are tightly controlled by mechanical environment and proper mechanotransduction ensures that fibroblast activities cease after completion of the tissue repair process. Conversely, dysregulated mechanotransduction often results in fibroblast over-activation or persistence beyond the state of normal repair. The resulting pathological accumulation of extracellular matrix is called fibrosis, a condition that has been associated with over 40% of all deaths in the industrialized countries. Consequently, elements in fibroblast mechanotransduction are scrutinized for their suitability as anti-fibrotic therapeutic targets. We review the current knowledge on mechanically relevant factors in the fibroblast extracellular environment, cell-matrix and cell-cell adhesion structures, stretch-activated membrane channels, stress-regulated cytoskeletal structures, and co-transcription factors. We critically discuss the targetability of these elements in therapeutic approaches and their progress in pre-clinical and/or clinical trials to treat organ fibrosis.