Synthetic Prostacyclin Agonist Attenuates Pressure-Overloaded Cardiac Fibrosis by Inhibiting FMT

Prostanoids in Cardiac and Vascular Remodeling

Prostanoids are biologically active lipids generated from arachidonic acid by the action of the COX (cyclooxygenase) isozymes. NSAIDs, which reduce the biosynthesis of prostanoids by inhibiting COX activity, are effective anti-inflammatory, antipyretic, and analgesic drugs. However, their use is limited by cardiovascular adverse effects, including myocardial infarction, stroke, hypertension, and heart failure. While it is well established that NSAIDs increase the risk of atherothrombotic events and hypertension by suppressing vasoprotective prostanoids, less is known about the link between NSAIDs and heart failure risk. Current evidence indicates that NSAIDs may increase the risk for heart failure by promoting adverse myocardial and vascular remodeling. Indeed, prostanoids play an important role in modulating structural and functional changes occurring in the myocardium and in the vasculature in response to physiological and pathological stimuli. This review will summarize current knowledge of the role of the different prostanoids in myocardial and vascular remodeling and explore how maladaptive remodeling can be counteracted by targeting specific prostanoids.

Acacetin Alleviates Cardiac Fibrosis via TGF-β1/Smad and AKT/mTOR Signal Pathways in Spontaneous Hypertensive Rats

INTRODUCTION

Attenuating cardiac fibroblasts activation contributes to reducing excessive extracellular matrix deposition and cardiac structural remodeling in hypertensive hearts. Acacetin plays a protective role in doxorubicin-induced cardiomyopathy and ischemia/reperfusion injury. The aim of this study was to investigate the potential molecular mechanisms underlying the protective role of acacetin on hypertension-induced cardiac fibrosis.

METHODS

Echocardiography, histopathological methods, and Western blotting techniques were used to evaluate the anti-fibrosis effects in spontaneous hypertensive rat (SHR) which were daily intragastrically administrated with acacetin (10 mg/kg and 20 mg/kg) for 6 weeks. Angiotensin II (Ang II) was used to induce cellular fibrosis in human cardiac fibroblasts (HCFs) in the absence and presence of acacetin treatment for 48 h.

RESULTS

Acacetin significantly alleviated hypertension-induced increase in left ventricular (LV) posterior wall thickness and LV mass index in SHR. The expressions of collagen-1, collagen-III, and alpha-smooth muscle actin (α-SMA) were remarkedly decreased after treatment with acacetin (n = 6, p < 0.05). In cultured HCFs, acacetin significantly attenuated Ang II-induced migration and proliferation (n = 6, p < 0.05). Moreover, acacetin substantially inhibited Ang II-induced upregulation of collagen-1 and collagen-III (n = 6, p < 0.05) and downregulated the expression of alpha-SMA in HCFs. Additionally, acacetin decreased the expression of TGF-β1, p-Smad3/Smad3, and p-AKT and p-mTOR but increased the expression of Smad7 (n = 6, p < 0.05). Further studies found that acacetin inhibited TGF-β1 agonist SRI and AKT agonist SC79 caused fibrotic effect.

CONCLUSION

Acacetin inhibits the hypertension-associated cardiac fibrotic processes through regulating TGF-β/Smad3, AKT/mTOR signal transduction pathways.

Stiff substrates inhibit collagen accumulation via integrin α2β1, FAK and Src kinases in human atrial fibroblast and myofibroblast cultures derived from patients with aortal stenosis

The aim of the study was to confirm whether cell substrate stiffness may participate in the regulation of fibrosis. The involvement of integrin α2β1, focal adhesion kinase (FAK) and Src kinase in signal transmission was investigated. Human atrial fibroblasts and myofibroblasts were cultured in both soft (2.23 ± 0.8 kPa) and stiff (8.28 ± 1.06 kPa) polyacrylamide gels. The cells were derived from the right atrium of patients with aortal stenosis undergoing surgery. The isolated cells, identified as fibroblasts or myofibroblasts, were stained positively with α smooth muscle actin, vimentin and desmin. The cultures settled on stiff gel demonstrated lower intracellular collagen and collagen type I telopeptide (PICP) levels; however, no changes in α1 chain of procollagen type I and III expression were noted. Inhibition of α2β1 integrin by TC-I 15 (10^-7 and 10^-8 M) or α2 integrin subunit silencing augmented intracellular collagen level. Moreover, FAK or Src kinase inhibitors increased collagen content within the culture. Lower TIMP4 secretion was reported within the stiff gel cultures but neither MMP 2 nor TIMP-1, 2 or 3 release was altered. The stiff substrate cultures also demonstrated lower interleukin-6 release. Substrate stiffness modified collagen deposition within the atrial fibroblast and myofibroblast cultures. The elasticity of the cellular environment exerts a regulatory influence on both synthesis and breakdown of collagen. Integrin α2β1, FAK and Src kinase activity participates in signal transmission, which may influence fibrosis in the atria of the human heart.

Enhanced myocardial blood flow in ischemic cardiomyopathy by a slow-release synthetic prostacyclin agonist combined with coronary artery bypass grafting: The first human study in a Phase I/IIa clinical trial

Background

YS-1402, which is a polymerized form of the synthetic prostacyclin agonist ONO-1301, has been proven in several preclinical studies to induce therapeutic effects for patients with ischemic cardiomyopathy (ICM). In this human study, we assessed the safety, tolerability, and efficacy of YS-1402, combined with coronary artery bypass grafting (CABG), for ICM.

Methods

Twenty-four patients with ICM whose left ventricular ejection fraction was <40% with an indication for CABG were double-blindly assigned to four groups: placebo, 10-mg YS-1402, 30-mg YS-1402, and 100-mg YS-1402. YS-1402 or placebo medications were administered on the surface of the left ventricle at the time of the CABG. Pre- and postoperative cardiac function and myocardial blood flow were assessed for 6 months postoperatively, along with a safety assessment.

Results

No severe adverse events were related to YS-1402. The maximum blood concentration of ONO-1301 was less than that of the no observable adverse effect level. Significantly increased myocardial blood flow (MBF) and cardiac function were observed in the YS-1402 group 26 weeks postoperatively, although no improvement in MBF occurred in the placebo group.

Conclusion

This Phase I/IIa parallel group-controlled, dose-escalation study of YS-1402 combined with CABG for ICM demonstrated the safety, tolerability, and potential efficacy of YS-1402.

IFN-α-2b Reduces Postoperative Arthrofibrosis in Rats by Inhibiting Fibroblast Proliferation and Migration through STAT1/p21 Signaling Pathway

Objective

To investigate the effect of IFN-α-2b in preventing postoperative arthrofibrosis in rats, its antiproliferation effect on fibroblasts in vitro, and its molecular mechanism.

Methods

The rat model of arthrofibrosis was established and treated with different concentrations of drugs. Knee specimens were collected for histological and immunohistochemical staining to observe the effect of IFN-α-2b on arthrofibrosis in rats. The biological information was further mined according to the database data, and the possible regulatory mechanism of IFN-α-2b on fibroblasts was analyzed. The inhibitory effect of IFN-α-2b on fibroblast proliferation and migration in vitro was detected by cell counting kit-8 (CCK-8), immunofluorescence analysis, cell cycle test, EdU assay, wound healing test, and Transwell method, and the analysis results were verified by Western blotting method.

Results

The test results of rat knee joint specimens showed that IFN-α-2b significantly inhibited the degree of fibrosis after knee joint surgery, the number of fibroblasts in the operation area was less than that of the control group, and the expression of collagen and proliferation-related proteins decreased. In vitro experimental results show that IFN-α-2b can inhibit the proliferation and migration of fibroblasts. According to the results of database analysis, it is suggested that the STAT1/P21 pathway may be involved, and it has been verified and confirmed by Western blotting and other related methods.

Conclusion

IFN-α-2b can reduce surgery-induced arthrofibrosis by inhibiting fibroblast proliferation and migration, which may be related to the regulation of STAT1/p21 signaling pathway.

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.

A novel prostaglandin I2 agonist, ONO-1301, attenuates liver inflammation and suppresses fibrosis in non-alcoholic steatohepatitis model mice

BACKGROUND

ONO-1301 is a novel long-lasting prostaglandin (PG) I₂ mimetic with inhibitory activity on thromboxane (TX) A₂ synthase. This drug can also induce endogenous prostaglandin (PG)I2 and PGE2 levels. Furthermore, ONO-1301 acts as a cytokine inducer and can initiate tissue repair in a variety of diseases, such as pulmonary hypertension, pulmonary fibrosis, cardiac infarction, and obstructive nephropathy. In this study, our aim was to evaluate the effect of ONO-1301 on liver inflammation and fibrosis in a mouse model of non-alcoholic steatohepatitis (NASH).

METHODS

The therapeutic effects of ONO-1301 against liver damage, fibrosis, and occurrence of liver tumors were evaluated using melanocortin 4 receptor-deficient (Mc4r-KO) NASH model mice. The effects of ONO-1301 against macrophages, hepatic stellate cells, and endothelial cells were also evaluated in vitro.

RESULTS

ONO-1301 ameliorated liver damage and fibrosis progression, was effective regardless of NASH status, and suppressed the occurrence of liver tumors in Mc4r-KO NASH model mice. In the in vitro study, ONO-1301 suppressed LPS-induced inflammatory responses in cultured macrophages, suppressed hepatic stellate cell (HSC) activation, upregulated vascular endothelial growth factor (VEGF) expression in HSCs, and upregulated hepatocyte growth factor (HGF) and VEGF expression in endothelial cells.

CONCLUSIONS

The results of our study highlight the potential of ONO-1301 to reverse the progression and prevent the occurrence of liver tumors in NASH using in vivo and in vitro models. ONO-1301 is a multidirectional drug that can play a key role in various pathways and can be further analyzed for use as a new drug candidate against NASH.

The Roles of Various Prostaglandins in Fibrosis: A Review

Organ fibrosis is a common pathological result of various chronic diseases with multiple causes. Fibrosis is characterized by the excessive deposition of extracellular matrix and eventually leads to the destruction of the tissue structure and impaired organ function. Prostaglandins are produced by arachidonic acid through cyclooxygenases and various prostaglandin-specific synthases. Prostaglandins bind to homologous receptors on adjacent tissue cells in an autocrine or paracrine manner and participate in the regulation of a series of physiological or pathological processes, including fibrosis. This review summarizes the properties, synthesis, and degradation of various prostaglandins, as well as the roles of these prostaglandins and their receptors in fibrosis in multiple models to reveal the clinical significance of prostaglandins and their receptors in the treatment of fibrosis.

Growth factor mimetics for skin regeneration: In vitro profiling of primary human fibroblasts and keratinocytes

Small molecules have gained considerable interest in regenerative medicine, as they can effectively modulate cell fates in a spatiotemporal controllable fashion. A continuous challenge in the field represents genuine mimicry or activation of growth factor signaling with small molecules. Here, we selected and profiled three compounds for their capacity to directly or indirectly activate endogenous FGF-2, VEGF, or SHH signaling events in the context of skin regeneration. Phenotypic and functional analysis of primary skin fibroblasts and keratinocytes revealed unique, cell-specific activity profiles for the FGF-2 mimetic SUN11602 and the putative VEGF mimetic ONO-1301. Whereas SUN11602 exclusively stimulated keratinocyte differentiation, ONO-1301 mainly affected the proliferation and migration behavior of fibroblasts. In each skin cell type, both compounds selectively enhanced the expression of MMP1 and VEGFA. A combined small molecule FGF-2/VEGF mimicry may not only improve angiogenesis-related microcirculation but also reduce early fibrosis while facilitating wound remodeling at later stages. SUN11602 and ONO-1301 represent valuable tools for improving the management of difficult-to-heal wounds, particularly for the design and development of small molecule-functionalized, next-generation, engineered skin substitutes.