Acetylsalicylic acid inhibits IL-18-induced cardiac fibroblast migration through the induction of RECK

RECK as a Potential Crucial Molecule for the Targeted Treatment of Sepsis

Reversion inducing cysteine rich protein with kazal motifs (RECK), a Kazal motif-containing protein, regulates pro-inflammatory cytokines production, migration of inflammatory cells, vascular endothelial growth factor (VEGF) and Wnt pathways and plays critical roles in septic inflammatory storms and vascular endothelial dysfunction. Recently, RECK has been defined as the negative regulator of adisintegrin and metalloproteinases (ADAMs) and matrix metalloproteinases (MMPs), which are both membrane "molecular scissors" and aggravate the poor prognosis of sepsis. To better understand the roles of RECK and the related mechanisms, we make here a systematic and in-depth review of RECK. We first summarize the findings on structural characteristics of RECK protein and the regulation at the transcription, post-transcription, or protein level of RECK. Then, we discuss the roles of RECK in inflammation, infection, and vascular injury by focusing on the RECK function on ADAMs and MMPs, as well as the pathways of VEGF, WNT, angiopoietin, and notch signaling. In conclusion, RECK participation as a guardian in the development of sepsis provides insight into the strategies of precisely intervening in RECK dysregulationfor the treatment of sepsis.

EF24, a Curcumin Analog, Reverses Interleukin-18-Induced miR-30a or miR-342-Dependent TRAF3IP2 Expression, RECK Suppression, and the Proinflammatory Phenotype of Human Aortic Smooth Muscle Cells

Curcumin, a polyphenolic compound derived from the widely used spice Curcuma longa, has shown anti-atherosclerotic effects in animal models and cultured vascular cells. Inflammation is a major contributor to atherosclerosis development and progression. We previously reported that the induction of the proinflammatory molecule TRAF3IP2 (TRAF3 Interacting Protein 2) or inhibition of the matrix metallopeptidase (MMP) regulator RECK (REversion Inducing Cysteine Rich Protein with Kazal Motifs) contributes to pro-oxidant, proinflammatory, pro-mitogenic and pro-migratory effects in response to external stimuli in vascular smooth muscle cells. Here we hypothesized that EF24, a curcumin analog with a better bioavailability and bioactivity profile, reverses interleukin (IL)-18-induced TRAF3IP2 induction, RECK suppression and the proinflammatory phenotype of primary human aortic smooth muscle cells (ASMC). The exposure of ASMC to functionally active recombinant human IL-18 (10 ng/mL) upregulated TRAF3IP2 mRNA and protein expression, but markedly suppressed RECK in a time-dependent manner. Further investigations revealed that IL-18 inhibited both miR-30a and miR-342 in a p38 MAPK- and JNK-dependent manner, and while miR-30a mimic blunted IL-18-induced TRAF3IP2 expression, miR-342 mimic restored RECK expression. Further, IL-18 induced ASMC migration, proliferation and proinflammatory phenotype switching, and these effects were attenuated by TRAF3IP2 silencing, and the forced expression of RECK or EF24. Together, these results suggest that the curcumin analog EF24, either alone or as an adjunctive therapy, has the potential to delay the development and progression of atherosclerosis and other vascular inflammatory and proliferative diseases by differentially regulating TRAF3IP2 and RECK expression in ASMC.

Empagliflozin Reverses Oxidized LDL-Induced RECK Suppression, Cardiotrophin-1 Expression, MMP Activation, and Human Aortic Smooth Muscle Cell Proliferation and Migration

Persistent oxidative stress and inflammation contribute causally to smooth muscle cell (SMC) proliferation and migration, the characteristic features of vascular proliferative diseases. Oxidatively modified low-density lipoproteins (OxLDL) elevate oxidative stress levels, inflammatory responses, and matrix metallopeptidase (MMP) activation, resulting ultimately in SMC migration, proliferation, and phenotype change. Reversion-inducing cysteine-rich protein with Kazal motifs (RECK) is a membrane-anchored MMP inhibitor. Empagliflozin is an SGLT2 inhibitor and exerts pleiotropic cardiovascular protective effects, including antioxidant and anti-inflammatory effects. Here, we investigated (i) whether OxLDL regulates RECK expression, (ii) whether ectopic expression of RECK reverses OxLDL-induced SMC migration and proliferation, and (iii) whether pretreatment with empagliflozin reverses OxLDL-induced RECK suppression, MMP activation, and SMC migration, proliferation, and differentiation. Indeed, results show that OxLDL at pathophysiological concentration promotes SMC migration and proliferation via NF-κB/miR-30b-dependent RECK suppression. Moreover, OxLDL changed the SMC phenotype to a more pro-inflammatory type, and this effect is blunted by RECK overexpression. Further, treatment with empagliflozin reversed OxLDL-induced miR-30b induction, RECK suppression, MMP activation, SMC migration, proliferation, and proinflammatory phenotype changes. OxLDL-induced cardiotrophin (CT)-1 expression and CT-1 stimulated SMC proliferation and migration in part via leukemia inhibitory factor receptor (LIFR) and glycoprotein 130 (gp130). Ectopic expression of RECK inhibited these effects by physically associating with LIFR and gp130, as evidenced by immunoprecipitation/immunoblotting and double immunofluorescence. Importantly, empagliflozin inhibited CT-1-induced mitogenic and migratory effects. Together, these results suggest the therapeutic potential of sustaining RECK expression or empagliflozin in vascular diseases characterized by SMC proliferation and migration.

'Youthful' phenotype of c-Kit+ cardiac fibroblasts

Cardiac fibroblast (CF) population heterogeneity and plasticity present a challenge for categorization of biological and functional properties. Distinct molecular markers and associated signaling pathways provide valuable insight for CF biology and interventional strategies to influence injury response and aging-associated remodeling. Receptor tyrosine kinase c-Kit mediates cell survival, proliferation, migration, and is activated by pathological injury. However, the biological significance of c-Kit within CF population has not been addressed. An inducible reporter mouse detects c-Kit promoter activation with Enhanced Green Fluorescent Protein (EGFP) expression in cardiac cells. Coincidence of EGFP and c-Kit with the DDR2 fibroblast marker was confirmed using flow cytometry and immunohistochemistry. Subsequently, CFs expressing DDR2 with or without c-Kit was isolated and characterized. A subset of DDR2+ CFs also express c-Kit with coincidence in ~ 8% of total cardiac interstitial cells (CICs). Aging is associated with decreased number of c-Kit expressing DDR2+ CFs, whereas pathological injury induces c-Kit and DDR2 as well as the frequency of coincident expression in CICs. scRNA-Seq profiling reveals the transcriptome of c-Kit expressing CFs as cells with transitional phenotype. Cultured cardiac DDR2+ fibroblasts that are c-Kit+ exhibit morphological and functional characteristics consistent with youthful phenotypes compared to c-Kit- cells. Mechanistically, c-Kit expression correlates with signaling implicated in proliferation and cell migration, including phospho-ERK and pro-caspase 3. The phenotype of c-kit+ on DDR2+ CFs correlates with multiple characteristics of 'youthful' cells. To our knowledge, this represents the first evaluation of c-Kit biology within DDR2+ CF population and provides a fundamental basis for future studies to influence myocardial biology, response to pathological injury and physiological aging.

SGLT2 Inhibition for Cardiovascular Diseases, Chronic Kidney Disease, and NAFLD

Sodium glucose cotransporter 2 (SGLT-2) inhibitors are the latest class of antidiabetic medications. They prevent glucose reabsorption in the proximal convoluted tubule to decrease blood sugar. Several animal studies revealed that SGLT-2 is profoundly involved in the inflammatory response, fibrogenesis, and regulation of numerous intracellular signaling pathways. Likewise, SGLT-2 inhibitors markedly attenuated inflammation and fibrogenesis and improved the function of damaged organ in animal studies, observational studies, and clinical trials. SGLT-2 inhibitors can decrease blood pressure and ameliorate hypertriglyceridemia and obesity. Likewise, they improve the outcome of cardiovascular diseases such as heart failure, arrhythmias, and ischemic heart disease. SGLT-2 inhibitors are associated with lower cardiovascular and all-cause mortality as well. Meanwhile, they protect against nonalcoholic fatty liver disease (NAFLD), chronic kidney disease, acute kidney injury, and improve micro- and macroalbuminuria. SGLT-2 inhibitors can reprogram numerous signaling pathways to improve NAFLD, cardiovascular diseases, and renal diseases. For instance, they enhance lipolysis, ketogenesis, mitochondrial biogenesis, and autophagy while they attenuate the renin-angiotensin-aldosterone system, lipogenesis, endoplasmic reticulum stress, oxidative stress, apoptosis, and fibrogenesis. This review explains the beneficial effects of SGLT-2 inhibitors on NAFLD and cardiovascular and renal diseases and dissects the underlying molecular mechanisms in detail. This narrative review explains the beneficial effects of SGLT-2 inhibitors on NAFLD and cardiovascular and renal diseases using the results of latest observational studies, clinical trials, and meta-analyses. Thereafter, it dissects the underlying molecular mechanisms involved in the clinical effects of SGLT-2 inhibitors on these diseases.

Two RECK Splice Variants (Long and Short) Are Differentially Expressed in Patients with Stable and Unstable Coronary Artery Disease: A Pilot Study

Primary prevention is crucial for coronary heart disease (CAD) and the identification of new reliable biomarkers might help risk stratification or predict adverse coronary events. Alternative splicing (AS) is a less investigated genetic factors implicated in CAD etiology. We performed an RNA-seq study on PBMCs from CAD patients and control subjects (CTR) and observed 113 differentially regulated AS events (24 up and 89 downregulated) in 86 genes. The RECK (Reversion-inducing-cysteine-rich protein with Kazal motifs) gene was further analyzed in a larger case study (24 CTR subjects, 72 CAD and 32 AMI patients) for its Splicing-Index FC (FC = −2.64; p = 0.0217), the AS event involving an exon (exon 18), and its role in vascular inflammation and remodeling. We observed a significant downregulation of Long RECK splice variant (containing exon 18) in PBMCs of AMI compared to CTR subjects (FC = −3.3; p < 0.005). Interestingly, the Short RECK splice variant (lacking exon 18) was under-expressed in AMI compared to both CTR (FC = −4.5; p < 0.0001) and CAD patients (FC = −4.2; p < 0.0001). A ROC curve, constructed combining Long and Short RECK expression data, shows an AUC = 0.81 (p < 0.001) to distinguish AMI from stable CAD patients. A significant negative correlation between Long RECK and triglycerides in CTR group and a positive correlation in the AMI group was found. The combined evaluation of Long and Short RECK expression levels is a potential genomic biomarker for the discrimination of AMI from CAD patients. Our results underline the relevance of deeper studies on the expression of these two splice variants to elucidate their functional role in CAD development and progression.

Reversion inducing cysteine rich protein with Kazal motifs and cardiovascular diseases: The RECKlessness of adverse remodeling

The Reversion Inducing Cysteine Rich Protein With Kazal Motifs (RECK) is a glycosylphosphatidylinositol (GPI) anchored membrane-bound regulator of matrix metalloproteinases (MMPs). It is expressed throughout the body and plays a role in extracellular matrix (ECM) homeostasis and inflammation. In initial studies, RECK expression was found to be downregulated in various invasive cancers and associated with poor prognostic outcome. Restoring RECK, however, has been shown to reverse the metastatic phenotype. Downregulation of RECK expression is also reported in non-malignant diseases, such as periodontal disease, renal fibrosis, and myocardial fibrosis. As such, RECK induction has therapeutic potential in several chronic diseases. Mechanistically, RECK negatively regulates various matrixins involved in cell migration, proliferation, and adverse remodeling by targeting the expression and/or activation of multiple MMPs, A Disintegrin And Metalloproteinase Domain-Containing Proteins (ADAMs), and A Disintegrin And Metalloproteinase With Thrombospondin Motifs (ADAMTS). Outside of its role in remodeling, RECK has also been reported to exert anti-inflammatory effects. In cardiac diseases, for example, it has been shown to counteract several downstream effectors of Angiotensin II (Ang-II) that play a role in adverse cardiac and vascular remodeling, such as Interleukin-6 (IL-6)/IL-6 receptor (IL-6R)/glycoprotein 130 (IL-6 signal transducer) signaling and Epidermal Growth Factor Receptor (EGFR) transactivation. This review article focuses on the current understanding of the multifunctional effects of RECK and how its downregulation may contribute to adverse cardiovascular remodeling.

The Role of RECK in Hepatobiliary Neoplasia Reveals Its Therapeutic Potential in NASH

Non-alcoholic fatty liver disease (NAFLD) is a multimorbidity disorder ranging from excess accumulation of fat in the liver (steatosis) to steatohepatitis (NASH) and end-stage cirrhosis, and the development of hepatocellular carcinoma (HCC) in a subset of patients. The defining features of NASH are inflammation and progressive fibrosis. Currently, no pharmaceutical therapies are available for NAFLD, NASH and HCC; therefore, developing novel treatment strategies is desperately needed. Reversion Inducing Cysteine Rich Protein with Kazal motifs (RECK) is a well-known modifier of the extracellular matrix in hepatic remodeling and transition to HCC. More recently, its role in regulating inflammatory and fibrogenic processes has emerged. Here, we summarize the most relevant findings that extend our current understanding of RECK as a regulator of inflammation and fibrosis, and its induction as a potential strategy to blunt the development and progression of NASH and HCC.

The Capabilities of Amlodipine/Lisinopril Single-Pill Combination in the Treatment of Newly Diagnosed Arterial Hypertension in a Middle-Aged Patient (Case Report)

Arterial hypertension (AH) is one of the most significant modifiable risk factors that increase cardiovascular morbidity and mortality worldwide, including Russia. The complex of structural and functional changes in the heart that occurs during AH consists not only in the formation of left ventricular (LV) myocardial hypertrophy, but also in the myocardial stiffness increasing due to collagen formation and cardiomyocytes apoptosis. These abnormalities are substrate for diastolic function disturbances, electrical myocardial instability and ischemia. The article provides a clinical case of amlodipine/lisinopril single-pill combination (A/L SPC) use in real clinical practice in a patient with stage II grade 2 newly diagnosed AH and its effect on blood pressure and echocardiographic myocardial fibrosis markers, including speckle tracking parameters The high antihypertensive efficacy of A/L SPC, a favorable effect on blood pressure circadian rhythm, as well as pronounced target-organ protective properties, in particular the ability to reduce LV and left atrial stiffness, were demonstrated. So, we conclude that A/L SPC improve the elastic properties of the left heart.

Can Endothelial Glycocalyx Be a Major Morphological Substrate in Pre-Eclampsia?

Today pre-eclampsia (PE) is considered as a disease of various theories; still all of them agree that endothelial dysfunction is the leading pathogenic factor. Endothelial dysfunction is a sequence of permanent immune activation, resulting in the change of both the phenotype and the functions of an endothelial cell and of the extracellular layer associated with the cell membrane—endothelial glycocalyx (eGC). Numerous studies demonstrate that eGC mediates and regulates the key functions of endothelial cells including regulation of vascular tone and thromboresistance; and these functions are disrupted during PE. Taking into account that eGC and its components undergo alterations under pathological conditions leading to endothelial activation, it is supposed that eGC plays a certain role in pathogenesis of PE. Envisaging the eGC damage as a key factor of PE, might be a new approach to prevention, treatment, and rehabilitation of patients with PE. This approach could include the development of drugs protecting eGC and promoting regeneration of this structure. Since the issue of PE is far from being solved, any effort in this direction might be valuable.

Role of interleukins in heart failure with reduced ejection fraction

Heart failure (HF) is the leading cause of morbidity and mortality in developed countries, and it is the primary cause of mortality in the elderly worldwide. The processes of inflammatory response activation, production and release of pro-inflammatory cytokines, activation of the complement system, synthesis of autoantibodies, and overexpression of Class II major histocompatibility complex molecules contribute to the HF development and progression. High levels of circulating cytokines correlate with the severity of HF, measured with the use of New York Heart Association's classification, and prognosis of the disease. In HF, there is an imbalance between pro-inflammatory and anti-inflammatory cytokines. Concentrations of several interleukins are increased in HF, including IL-1β, IL-6, IL-8, IL-9, IL-10, IL-13, IL-17, and IL-18, whereas the levels of IL-5, IL-7, or IL-33 are down-regulated. Concentrations of inflammatory mediators are associated with cardiac function and can be HF markers and predictors of adverse outcomes or mortality. This review presents the role of interleukins, which contribute to the HF initiation and progression, the importance of their pathways in transition from myocardial injury to HF, and the role of interleukins as markers of disease severity and outcome predictors.

Effect of the Single-Pill Amlodipine/Valsartan Combination on Hypertrophy and Myocardial Deformation Characteristics in Middle-Aged Patients with Essential Arterial Hypertension

Aim. To investigate the impact of amlodipine/valsartan single-pill combination (A/V SPC) on left ventricular hypertrophy (LVH) and left ventricular (LV) myocardial strain and stiffness parameters in naїve middle-aged patients with stage II grade 1-2 essential arterial hypertension (EAH).Material and methods. A group of patients with stage II grade 1-2 EAH who had not previously received regular antihypertensive treatment (AHT) [n=38; mean age 49.7±7.0 years] was retrospectively formed. All the patients were treated with A/V SPC and all of them achieved target office blood pressure (BP) (less than 140/90 mm Hg). And after 12 weeks follow-up (since the time of reaching the target BP) the AHT effectiveness assessment, its impact on LVH and LV myocardial strain and stiffness parameters (general clinical data, ambulatory blood pressure monitoring, conventional and 2D-speckle tracking echocardiography) were performed in all included patients.Results. The number of patients with LVH significantly (p=0.039) decreased from 25 individuals (65.8%) at baseline to 15 patients (39.5%) at the end of follow-up. Among patients with LVH at baseline after the treatment with A/V SPC significantly decreased (p<0.001 for all) interventricular septum thickness (from 1.36±0.19 to 1.28±0.18 cm), LV posterior wall thickness (from 1.08±0.09 to 0.97±0.11 cm) and the LV myocardial mass index (from 123.3±19.3 to 110.8±20.8 g/m2). At the end of follow-up end-systolic elastance significantly (p<0.001) decreased from 4.01±1.12 to 3.46±0.88 mm Hg/ml. In the subgroup of patients with reduced (in absolute value) LV longitudinal 2D-strain (n=27) at baseline, there was a significantly (p=0.005) increasing in this parameter at the end of the study (from -16.14±2.21% to -17.30±2.13%, Δ%=8.45±13.35).Conclusion. In naive patients 40-65 years old with stage II grade 1-2 EAH AHT with A/V SPC provides effective 24 hours BP control, significantly reduced LVH and improves LV strain parameters, which indicates decreasing of LV myocardial stiffness.

RECK suppresses interleukin-17/TRAF3IP2-mediated MMP-13 activation and human aortic smooth muscle cell migration and proliferation

Sustained inflammation and matrix metalloproteinase (MMP) activation contribute to vascular occlusive/proliferative disorders. Interleukin-17 (IL-17) is a proinflammatory cytokine that signals mainly via TRAF3 Interacting Protein 2 (TRAF3IP2), an upstream regulator of various critical transcription factors, including AP-1 and NF-κB. Reversion inducing cysteine rich protein with kazal motifs (RECK) is a membrane-anchored MMP inhibitor. Here we investigated whether IL-17A/TRAF3IP2 signaling promotes MMP-13-dependent human aortic smooth muscle cell (SMC) proliferation and migration, and determined whether RECK overexpression blunts these responses. Indeed, IL-17A treatment induced (a) JNK, p38 MAPK, AP-1, NF-κB, and CREB activation, (b) miR-21 induction, (c) miR-27b and miR-320 inhibition, (d) MMP-13 expression and activation, (e) RECK suppression, and (f) SMC migration and proliferation, all in a TRAF3IP2-dependent manner. In fact, gain of TRAG3IP2 function, by itself, induced MMP-13 expression and activation, and RECK suppression. Furthermore, treatment with recombinant MMP-13 stimulated SMC migration in part via ERK activation. Importantly, RECK gain-of-function attenuated MMP-13 activity without affecting its mRNA or protein levels, and inhibited IL-17A- and MMP-13-induced SMC migration. These results indicate that increased MMP-13 and decreased RECK contribute to IL-17A-induced TRAF3IP2-dependent SMC migration and proliferation, and suggest that TRAF3IP2 inhibitors or RECK inducers have the potential to block the progression of neointimal thickening in hyperplastic vascular diseases.

Low-dose aspirin reduces hypoxia-induced sFlt1 release via the JNK/AP-1 pathway in human trophoblast and endothelial cells

Pre-eclampsia (PE) is a serious hypertensive disorder of pregnancy that remains a leading cause of perinatal and maternal morbidity and mortality worldwide. Placental ischemia/hypoxia and the secretion of soluble fms-like tyrosine kinase 1 (sFlt1) into maternal circulation are involved in the pathogenesis of PE. Although low-dose aspirin (LDA) has beneficial effects on the prevention of PE, the exact mechanisms of action of LDA, particularly on placental dysfunction, and sFlt1 release, have not been well investigated. This study aimed to determine whether LDA exists the protective effects on placental trophoblast and endothelial functions and prevents PE-associated sFlt1 release. First, we observed that LDA mitigated hypoxia-induced trophoblast apoptosis, showed positive effects on trophoblast cells migration and invasion activity, and increased the tube-forming activity of human umbilical vein endothelial cells (HUVECs). In addition, LDA decreased hypoxia-induced sFlt1 production, and the c-Jun NH₂ -terminal kinase/activator protein-1 (JNK/AP-1) pathway was shown to mediate the induction of sFlt1. Moreover, the transcription factor AP-1 was confirmed to regulate the Flt1 gene expression by directly binding to the Flt1 promoter in luciferase assays. The result of chromatin immunoprecipitation assays further demonstrated that LDA could directly decrease the expression of the transcription factor AP-1, and thus decrease sFlt1 production. Finally, the effects of LDA on sFlt1 production were proved in human placental explants. Taken together, our data show the protective effects of LDA against trophoblast and endothelial cell dysfunction and reveal that the LDA-mediated inhibition of sFlt1 via the JNK/AP-1 pathway may be a potential cellular/molecular mechanism for the prevention of PE.

Chalcone flavokawain A attenuates TGF-β1-induced fibrotic pathology via inhibition of ROS/Smad3 signaling pathways and induction of Nrf2/ARE-mediated antioxidant genes in vascular smooth muscle cells

TGF‐β1 plays a crucial role in the pathogenesis of vascular fibrotic diseases. Chalcones are reportedly cancer chemo‐preventive food components that are rich in fruits and vegetables. In this study, flavokawain A (FKA, 2‐30 μM), a naturally occurring chalcone in kava extracts, was evaluated for its anti‐fibrotic and antioxidant properties in TGF‐β1‐stimulated vascular smooth muscle (A7r5) cells, as well as its underlying molecular mechanism of action. Immunofluorescence data showed down‐regulated F‐actin expression with FKA treatment in TGF‐β1‐stimulated A7r5 cells. Western blotting demonstrated that FKA treatment suppressed the expression of α‐SMA and fibronectin proteins under TGF‐β1 stimulation. Findings from wound‐healing and invasion experiments showed that FKA inhibits TGF‐β1‐mediated migration and invasion. Western blotting demonstrated that treatment with FKA down‐regulated MMP‐9 and MMP‐2 and up‐regulated TIMP‐1 expression. Further evidence showed that FKA decreased TGF‐β1‐mediated phosphorylation and the transcriptional activity of Smad3. TGF‐β1‐induced excessive ROS production was remarkably reversed by FKA treatment in A7r5 cells, and inhibition by FKA or N‐acetylcysteine (NAC) substantially diminished TGF‐β1‐induced p‐Smad3 activation and wound‐healing migration. Interestingly, FKA‐mediated antioxidant properties were associated with increased nuclear translocation of Nrf2 and elevated antioxidant response element (ARE) luciferase activity. Activation of Nrf2/ARE signaling was accompanied by the induction of HO‐1, NQO‐1 and γ‐GCLC genes in FKA‐treated A7r5 cells. Notably, silencing of Nrf2 (siRNA transfection) significantly diminished the FKA‐mediated antioxidant effects, indicating that FKA may inhibit TGF‐β1‐induced fibrosis through suppressing ROS generation in A7r5 cells. Our results suggested that anti‐fibrotic and antioxidant activities of the chalcone flavokawain A may contribute to the development of food‐based chemo‐preventive drugs for fibrotic diseases.

Characterization of fibroblasts from hypertrophied right ventricle of pulmonary hypertensive rats

Pulmonary arterial hypertension (PAH), which is characterized by an elevation of pulmonary arterial resistance, leads to a lethal right heart failure. It is an urgent issue to clarify the pathogenesis of PAH-induced right heart failure. The present study aimed to elucidate the characteristics of cardiac fibroblasts (CFs) isolated from hypertrophied right ventricles of monocrotaline (MCT)-induced PAH model rats. CFs were isolated from the right ventricles of MCT-injected rats (MCT-CFs) and saline-injected control rats (CONT-CFs). Expression of α-smooth muscle actin and collagen type I in MCT-CFs was lower than that in CONT-CFs. On the other hand, proliferation, migration, and matrix metalloproteinase (MMP)-9 production were significantly enhanced in MCT-CFs. In MCT-CFs, phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, c-Jun N-terminal kinase (JNK), and Ca²⁺/calmodulin-dependent protein kinase (CaMK) II was significantly enhanced. In addition to mRNA expression of Orai1, a Ca²⁺ release-activated Ca²⁺ channel, and stromal interaction molecules (STIM) 1, an endoplasmic reticulum Ca²⁺ sensor, the associated store-operated Ca²⁺ entry (SOCE) was significantly higher in MCT-CFs than CONT-CFs. Pharmacological inhibition of ERK1/2 pathway prevented the enhanced proliferation of MCT-CFs. The enhanced migration of MCT-CFs was prevented by a pharmacological inhibition of ERK1/2, JNK, CaMKII, or SOCE pathway. The enhanced MMP-9 production in MCT-CFs was prevented by a pharmacological inhibition of ERK1/2, CaMKII, or SOCE pathway but not JNK. The present results suggested that MCT-CFs exhibit proliferative and migratory phenotypes perhaps through multiple signaling pathways. This study for the first time determined the characteristics of CFs isolated from hypertrophied right ventricles of MCT-induced PAH model rats.

Aspirin alleviates cardiac fibrosis in mice by inhibiting autophagy

Aspirin (ASA) is a cardioprotective drug with anti-cardiac fibrosis action in vivo. This study was aimed to clarify the anti-cardiac fibrosis action of ASA and the underlying mechanisms. Two heart injury models (injection of isoproterenol and ligation of the left anterior descending branch) were used in mice to induce cardiac fibrosis. The animals were treated with ASA (10 mg·kg^-1·d^-1, ig) for 21 and 14 d, respectively. ASA administration significantly improved cardiac function, and ameliorated heart damage and fibrosis in the mice. The mechanisms underlying ASA's anti-fibrotic effect were further analyzed in neonatal cardiac fibroblasts (CFs) exposed to hypoxia in vitro. ASA (0.5-5 mmol/L) dose-dependently inhibited the proliferation and Akt phosphorylation in the CFs. In addition, ASA significantly inhibited CF apoptosis, and decreased the levels of apoptosis markers (cleaved caspase 3 and Parp1), which might serve as a side effect of anti-fibrotic effect of ASA. Furthermore, ASA dose-dependently inhibited the autophagy in the CFs, as evidenced by the reduced levels of autophagy marker LC3-II. The autophagy inhibitor Pepstatin A (PepA) promoted the inhibitory effect of ASA on CF proliferation, whereas the autophagy inducer rapamycin rescued ASA-caused inhibition of CF proliferation, suggesting an autophagy-dependent anti-proliferative effect of ASA. Both p38 inhibitor SB203580 and ROS scavenger N-acetyl-cysteine (NAC) significantly decreased Akt phosphorylation in CFs in the basal and hypoxic situations, but they both significantly increased LC3-II levels in the CFs. Our results suggest that an autophagy- and p38/ROS-dependent pathway mediates the anti-cardiac fibrosis effect of ASA in CFs. As PepA and SB203580 did not affect ASA-caused inhibition of CF apoptosis, the drug combination will enhance ASA's therapeutic effects.

Interleukin-18 deficiency protects against renal interstitial fibrosis in aldosterone/salt-treated mice

Interleukin (IL)-18 is a member of the IL-1 family of cytokines and was described originally as an interferon γ-inducing factor. Aldosterone plays a central role in the regulation of sodium and potassium homoeostasis by binding to the mineralocorticoid receptor and contributes to kidney and cardiovascular damage. Aldosterone has been reported to induce IL-18, resulting in cardiac fibrosis with induced IL-18-mediated osteopontin (OPN). We therefore hypothesized that aldosterone-induced renal fibrosis via OPN may be mediated by IL-18. To verify this hypothesis, we compared mice deficient in IL-18 and wild-type (WT) mice in a model of aldosterone/salt-induced hypertension. IL-18−/− and C57BL/6 WT mice were used for the uninephrectomized aldosterone/salt hypertensive model, whereas NRK-52E cells (rat kidney epithelial cells) were used in an in vitro model. In the present in vivo study, IL-18 protein expression was localized in medullary tubules in the WT mice, whereas in aldosterone-infused WT mice this expression was up-regulated markedly in the proximal tubules, especially in injured and dilated tubules. This renal damage caused by aldosterone was attenuated significantly by IL-18 knockout with down-regulation of OPN expression. In the present in vitro study, aldosterone directly induced IL-18 gene expression in renal tubular epithelial cells in a concentration- and time-dependent manner. These effects were inhibited completely by spironolactone. IL-18 may be a key mediator of aldosterone-induced renal fibrosis by inducing OPN, thereby exacerbating renal interstitial fibrosis. Inhibition of IL-18 may therefore provide a potential target for therapeutic intervention aimed at preventing the progression of renal injury.

MMP-9 signaling in the left ventricle following myocardial infarction

Following myocardial infarction (MI), the left ventricle (LV) undergoes a series of cardiac wound healing responses that involve both the stimulation of robust inflammation to clear necrotic myocytes and tissue debris and the induction of extracellular matrix (ECM) protein synthesis to generate an infarct scar. The collective changes in myocardial structure and function are termed LV remodeling, and matrix metalloproteinase-9 (MMP-9) is a key instigator of post-MI LV remodeling. Through direct molecular effects on ECM and inflammatory protein turnover as well as indirect effects on major cell types that coordinate cardiac wound healing, namely the infiltrating leukocytes and the cardiac fibroblasts, MMP-9 coordinates multiple aspects of LV remodeling. In this review, we will discuss recent research that has expanded our understanding of post-MI LV remodeling, including recent proteomic advances focused on the ECM compartment to provide novel functional and translational insights. This overview will summarize how our understanding of MMP-9 has evolved over the last decade and will provide insight into future directions that will drive our understanding of MMP-9-directed cardiac ECM turnover in the post-MI LV.

Novel therapeutic strategies targeting fibroblasts and fibrosis in heart disease

Our understanding of the functions of cardiac fibroblasts has moved beyond their roles in heart structure and extracellular matrix generation and now includes their contributions to paracrine, mechanical and electrical signalling during ontogenesis and normal cardiac activity. Fibroblasts also have central roles in pathogenic remodelling during myocardial ischaemia, hypertension and heart failure. As key contributors to scar formation, they are crucial for tissue repair after interventions including surgery and ablation. Novel experimental approaches targeting cardiac fibroblasts are promising potential therapies for heart disease. Indeed, several existing drugs act, at least partially, through effects on cardiac connective tissue. This Review outlines the origins and roles of fibroblasts in cardiac development, homeostasis and disease; illustrates the involvement of fibroblasts in current and emerging clinical interventions; and identifies future targets for research and development.

Histone deacetyltransferase inhibitors Trichostatin A and Mocetinostat differentially regulate MMP9, IL-18 and RECK expression, and attenuate Angiotensin II-induced cardiac fibroblast migration and proliferation

Histone acetylation/deacetylation plays a key role in the epigenetic regulation of multiple pro-fibrotic genes. Here we investigated the effects of histone deacetyltransferase (HDAC) inhibition on angiotensin (Ang)-II-induced pro-fibrotic changes in adult mouse cardiac fibroblasts (CF). CF express class I HDACs 1 and 2, and Ang-II induces their activation. Notably, silencing HDAC1 or HDAC2 attenuated Ang-II induced CF proliferation and migration. Under basal conditions, HDAC1 dimerizes with HDAC2 in CF and Ang-II reversed this interaction. Treatment with Trichostatin A (TSA), a broad-spectrum HDAC inhibitor, restored their physical association, and attenuated Ang-II-induced MMP9 expression, IL-18 induction, and extracellular matrix (collagen I, collagen III and fibronectin) production. Further, TSA inhibited Ang-II-induced MMP9 and Il18 transcription by blocking NF-κB and AP-1 binding to their respective promoter regions. By inhibiting Sp1 binding to RECK promoter, TSA reversed Ang-II-induced RECK suppression, collagen and fibronectin expression, and CF migration and proliferation. The class I-specific HDAC inhibitor Mocetinostat (MGCD) recapitulated TSA effects on Ang-II-treated CF. Together, these results demonstrate that targeting HDACs attenuates the pro-inflammatory and pro-fibrotic effects of Ang-II on CF.

Potential Role of Reversion-Inducing Cysteine-Rich Protein with Kazal Motifs (RECK) in Regulation of Matrix Metalloproteinases (MMPs) Expression in Periodontal Diseases

Periodontal diseases are characterized by pathological destruction of extracellular matrix (ECM) of periodontal tissues. Matrix metalloproteinases (MMPs) are a significant part of the degradation of ECM. However, the regulation of MMPs expression level in periodontal diseases is as yet undetermined.

RECK (reversion-inducing cysteine-rich protein with Kazal motifs), a novel membrane-anchored inhibitor of MMPs, could regulate the expressions of MMP-2, 9 and MT1-MMP as a cell surface-signaling molecule. Thus, we propose that RECK may play an important role in regulating MMPs in the ECM degradation of periodontal diseases. The RECK/MMPs signaling pathway could provide a new approach for prevention and treatment of RECK in periodontal diseases by blocking MMPs.

The Nox1/4 Dual Inhibitor GKT137831 or Nox4 Knockdown Inhibits Angiotensin-II-Induced Adult Mouse Cardiac Fibroblast Proliferation and Migration. AT1 Physically Associates With Nox4

Both oxidative stress and inflammation contribute to chronic hypertension-induced myocardial fibrosis and adverse cardiac remodeling. Here we investigated whether angiotensin (Ang)-II-induced fibroblast proliferation and migration are NADPH oxidase (Nox) 4/ROS and IL-18 dependent. Our results show that the potent induction of mouse cardiac fibroblast (CF) proliferation and migration by Ang-II is markedly attenuated by Nox4 knockdown and the Nox inhibitor DPI. Further, Nox4 knockdown and DPI pre-treatment attenuated Ang-II-induced IL-18, IL-18Rα and collagen expression, and MMP9 and LOX activation. While neutralization of IL-18 blunted Ang-II-induced CF proliferation and migration, knockdown of MMP9 attenuated CF migration. The antioxidant NAC and the cell-permeable SOD mimetics Tempol, MnTBAP, and MnTMPyP attenuated oxidative stress and inhibited CF proliferation and migration. The Nox1/Nox4 dual inhibitor GKT137831 also blunted Ang-II-induced H2 O2 production and CF proliferation and migration. Further, AT1 bound Nox4, and Ang-II enhanced their physical association. Notably, GKT137831 attenuated the AT1/Nox4 interaction. These results indicate that Ang-II induces CF proliferation and migration in part via Nox4/ROS-dependent IL-18 induction and MMP9 activation, and may involve AT1/Nox4 physical association. Thus, either (i) neutralizing IL-18, (ii) blocking AT1/Nox4 interaction or (iii) use of the Nox1/Nox4 inhibitor GKT137831 may have therapeutic potential in chronic hypertension-induced adverse cardiac remodeling.

Epigallocatechin gallate attenuates fibroblast proliferation and excessive collagen production by effectively intervening TGF-β1 signalling

Pulmonary fibrosis (PF) poses a huge burden to the patients and society due to lack of an effective treatment drug. Activation of fibrocyte, fibroblast and myofibroblasts are important steps in the development of PF. Targeting this common pathway with natural chemicals may lead to the development of new drug regimens for PF treatment. In this study, PF was induced in male Wistar rats by intratracheal administration of Bleomycin (BLM). Epigallocatechin gallate (EGCG) was administered to one of the groups of rats to test its efficacy against the development of PF. Bleomycin-induction resulted in significant elevation of matrix metalloproteinase (MMP)-2 and -9 expression, increased RNA and protein expression of transforming growth factor (TGF)-β1, Smads and alpha-smooth muscle actin (α-SMA). EGCG treatment normalized the BLM induced aberrations in these rats. The protective role of EGCG was also validated in vitro using the WI-38 fibroblast cell line. TGF-β1 incubated cells exhibited increased fibroblast proliferation and hydroxyproline levels with a concomitant decrease in the expression of MMPs 2 and 9. An increase in protein expression levels of p-Smad, α-SMA and type I collagen (COL1A) was also exhibited by fibroblasts upon TGF-β1 incubation. Simultaneous treatment of EGCG to WI-38 cells significantly decreased these protein expressions alongside normalizing the MMPs expression. The study revealed that EGCG inhibited fibroblast activation and collagen accumulation by inhibiting TGF-β1 signalling and thus can be considered as an effective drug against PF.

Tumor necrosis factor-alpha induces VCAM-1-mediated inflammation via c-Src-dependent transactivation of EGF receptors in human cardiac fibroblasts

BACKGROUND

Tumor necrosis factor-α (TNF-α) is a proinflammatory cytokine and elevated in the regions of tissue injury and inflammatory diseases. The deleterious effects of TNF-α on fibroblasts may aggravate heart inflammation mediated through the up-regulation of adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1). However, the mechanisms underlying TNF-α-induced VCAM-1 expression in cardiac fibroblasts remain unknown. This study aimed to investigate the roles of TNF-α in VCAM-1 expression and its effects on human cardiac fibroblasts (HCFs).

RESULTS

The primary culture HCFs were used in this study. The results obtained with Western blotting, real time-quantitative PCR, and promoter activity analyses showed that TNF-α-induced VCAM-1 expression was mediated through TNF receptor (TNFR) 1-dependent gene up-regulation. Activation of TNFR1 by TNF-α transactivated c-Src-dependent EGF receptor (EGFR) linking to PI3K/Akt cascade, and then led to transcriptional activity of NF-κB. Moreover, the results of promoter reporter assay demonstrated that the phosphorylated p65 NF-κB turned on VCAM-1 gene expression. Subsequently, up-regulation of VCAM-1 promoted monocytes adhesion to HCFs challenged with TNF-α determined by cell adhesion assay.

CONCLUSIONS

Taken together, these results indicate that in HCFs, activation of NF-κB by c-Src-mediated transactivation of EGFR/PI3K/Akt cascade is required for TNF-α-induced VCAM-1 expression. Finally, increased VCAM-1 enhances monocytes adhering to HCFs challenged with TNF-α. Understanding the mechanisms of VCAM-1 up-regulated by TNF-α on HCFs may provide rationally therapeutic interventions for heart injury or inflammatory diseases.

The role of interleukin-18 in glioblastoma pathology implies therapeutic potential of two old drugs-disulfiram and ritonavir

Based on reporting in the last several years, an impressive but dismal list of cytotoxic chemotherapies that fail to prolong the median overall survival of patients with glioblastoma has prompted the development of treatment protocols designed to interfere with growth-facilitating signaling systems by using non-cytotoxic, non-oncology drugs. Recent recognition of the pro-mobility stimulus, interleukin-18, as a driver of centrifugal glioblastoma cell migration allows potential treatment adjuncts with disulfiram and ritonavir. Disulfiram and ritonavir are well-tolerated, non-cytotoxic, non-oncology chemotherapeutic drugs that are marketed for the treatment of alcoholism and human immunodeficiency virus (HIV) infection, respectively. Both drugs exhibit an interleukin-18–inhibiting function. Given the favorable tolerability profile of disulfiram and ritonavir, the unlikely drug-drug interaction with temozolomide, and the poor prognosis of glioblastoma, trials of addition of disulfiram and ritonavir to current standard initial treatment of glioblastoma would be warranted.

Interleukin 18 and extracellular matrix metalloproteinase inducer cross-regulation: implications in acute myocardial infarction

Circulating interleukin-18 (IL-18) is thought to promote atherosclerosis and cardiovascular complications such as plaque rupture. Atherosclerosis is also characterized by smooth muscle cell migration, a consequence of extracellular matrix (ECM) degradation regulated by metalloproteinases (MMPs). Because extracellular matrix metalloproteinase inducer (EMMPRIN) has been shown to promote plaque instability by inducing ECM degradation and MMP synthesis, we investigated whether a cross-regulatory interaction exists between IL-18 and EMMPRIN in human monocytes. EMMPRIN levels in monocytes were markedly greater in 20 patients with acute myocardial infarction (AMI) compared with 20 patients with stable angina pectoris or 20 healthy volunteers (control group). The levels of IL-18 and MMP-9 in serum were also significantly greater in the AMI group in comparison with the other 2 groups. IL-18 levels positively correlated with increased levels of EMMPRIN in monocytes. In vitro, the expression of EMMPRIN was increased in monocytes cultured with IL-18, and IL-18 secretion was augmented in monocytes cultured with EMMPRIN. Gene silencing of EMMPRIN by small interfering RNA reduced monocyte secretion of both IL-18 and MMP-9. In the present study, cross-regulation between IL-18 and EMMPRIN in monocytes was demonstrated. This interaction may amplify the inflammatory cascade and be responsible for increased monocytic MMP-9 serum levels in atherosclerosis, contributing to atherosclerotic plaque destabilization and subsequent AMI.

Antiproliferative effects of aspirin and diclofenac against the growth of cancer and fibroblast cells: In vitro comparative study

Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit the growth of several cancer cell lines. The aim of this study is to compare the cytotoxic effect of aspirin with diclofenac on the growth of HeLa cell, mammary cell carcinoma, rhabdomyosarcoma and fibroblast cell lines in the culture media. The cells are cultured in RPMI-1640 culture media supplemented with 5% fetal calf serum and antibiotics. Aspirin (5 mg/well) and diclofenac (0.625 mg/well) significantly inhibit the growth of HeLa, rhabdomyosarcoma and fibroblast cells. The cytotoxic effect of aspirin against rhabdomyosarcoma is significantly (p < 0.001) higher than that of diclofenac with a potency approximated 2.6. It concludes that aspirin and diclofenac inhibit the growth of fibroblast and cancer cell by inhibiting the up-regulation of cyclooxygenases enzymes in cancer cells. Aspirin is more effective than diclofenac against the growth of rhabdomyosarcoma cell line.

Pressure overload induces IL-18 and IL-18R expression, but markedly suppresses IL-18BP expression in a rabbit model. IL-18 potentiates TNF-α-induced cardiomyocyte death

Recurrent or sustained inflammation plays a causal role in the development and progression of left ventricular hypertrophy (LVH) and its transition to failure. Interleukin (IL)-18 is a potent pro-hypertrophic inflammatory cytokine. We report that induction of pressure overload in the rabbit, by constriction of the descending thoracic aorta induces compensatory hypertrophy at 4weeks (mass/volume ratio: 1.7±0.11) and ventricular dilatation indicative of heart failure at 6weeks (mass/volume ratio: 0.7±0.04). In concordance with this, fractional shortening was preserved at 4weeks, but markedly attenuated at 6weeks. We cloned rabbit IL-18, IL-18Rα, IL-18Rβ, and IL-18 binding protein (IL-18BP) cDNA, and show that pressure overload, while enhancing IL-18 and IL-18R expression in hypertrophied and failing hearts, markedly attenuated the level of expression of the endogenous IL-18 antagonist IL-18BP. Cyclical mechanical stretch (10% cyclic equibiaxial stretch, 1Hz) induced hypertrophy of primary rabbit cardiomyocytes in vitro and enhanced ANP, IL-18, and IL-18Rα expression. Further, treatment with rhIL-18 induced its own expression and that of IL-18Rα via AP-1 activation, and induced cardiomyocyte hypertrophy in part via PI3K/Akt/GATA4 signaling. In contrast, IL-18 potentiated TNF-α-induced cardiomyocyte death, and by itself induced cardiac endothelial cell death. These results demonstrate that pressure overload is associated with enhanced IL-18 and its receptor expression in hypertrophied and failingrabbit hearts. Since IL-18BP expression is markedly inhibited, our results indicate a positive amplification in IL-18 proinflammatory signaling during pressure overload, and suggest IL-18 as a potential therapeutic target in pathological hypertrophy and cardiac failure.

Docosahexaenoic acid reverses angiotensin II-induced RECK suppression and cardiac fibroblast migration

The omega-3 polyunsaturated fatty acids (ω-3 fatty acids) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been reported to inhibit or delay the progression of cardiovascular diseases, including myocardial fibrosis. Recently we reported that angiotensin II (Ang II) promotes cardiac fibroblast (CF) migration by suppressing the MMP regulator reversion-inducing-cysteine-rich protein with Kazal motifs (RECK), through a mechanism dependent on AT1, ERK, and Sp1. Here we investigated the role of miR-21 in Ang II-mediated RECK suppression, and determined whether the ω-3 fatty acids reverse these effects. Ang II induced miR-21 expression in primary mouse cardiac fibroblasts (CFs) via ERK-dependent AP-1 and STAT3 activation, and while a miR-21 inhibitor reversed Ang II-induced RECK suppression, a miR-21 mimic inhibited both RECK expression and Ang II-induced CF migration. Moreover, Ang II suppressed the pro-apoptotic PTEN, and the ERK negative regulator Sprouty homologue 1 (SPRY1), but induced the metalloendopeptidase MMP2, all in a manner that was miR-21-dependent. Further, forced expression of PTEN inhibited Akt phosphorylation, Sp1 activation, and MMP2 induction. Notably, while both EPA and DHA reversed Ang II-mediated RECK suppression, DHA appeared to be more effective, and reversed Ang II-induced miR-21 expression, RECK suppression, MMP2 induction, and CF migration. These results indicate that Ang II-induced CF migration is differentially regulated by miR-21-mediated MMP induction and RECK suppression, and that DHA has the potential to upregulate RECK, and therefore may exert potential beneficial effects in cardiac fibrosis.

Oxidative Stress and Skin Fibrosis

Fibrosis is defined as increased fibroblast proliferation and deposition of extracellular matrix components with potential clinical ramifications including organ dysfunction and failure. Fibrosis is a characteristic finding of various skin diseases which can have life-threatening consequences. These implications call for research into this topic as only a few treatments targeting fibrosis are available. In this review, we discuss oxidative stress and its role in skin fibrosis. Recent studies have implicated the importance of oxidative stress in a variety of cellular pathways directly and indirectly involved in the pathogenesis of skin fibrosis. The cellular pathways by which oxidative stress affects specific fibrotic skin disorders are also reviewed. Finally, we also describe various therapeutic approaches specifically targeting oxidative stress to prevent skin fibrosis. We believe oxidative stress is a relevant target, and understanding the role of oxidative stress in skin fibrosis will enhance knowledge of fibrotic skin diseases and potentially produce targeted therapeutic options.