Oncostatin M Promotes Osteoblastic Differentiation of Human Vascular Smooth Muscle Cells Through JAK3-STAT3 Pathway

Macrophages in cardiovascular diseases: molecular mechanisms and therapeutic targets

The immune response holds a pivotal role in cardiovascular disease development. As multifunctional cells of the innate immune system, macrophages play an essential role in initial inflammatory response that occurs following cardiovascular injury, thereby inducing subsequent damage while also facilitating recovery. Meanwhile, the diverse phenotypes and phenotypic alterations of macrophages strongly associate with distinct types and severity of cardiovascular diseases, including coronary heart disease, valvular disease, myocarditis, cardiomyopathy, heart failure, atherosclerosis and aneurysm, which underscores the importance of investigating macrophage regulatory mechanisms within the context of specific diseases. Besides, recent strides in single-cell sequencing technologies have revealed macrophage heterogeneity, cell-cell interactions, and downstream mechanisms of therapeutic targets at a higher resolution, which brings new perspectives into macrophage-mediated mechanisms and potential therapeutic targets in cardiovascular diseases. Remarkably, myocardial fibrosis, a prevalent characteristic in most cardiac diseases, remains a formidable clinical challenge, necessitating a profound investigation into the impact of macrophages on myocardial fibrosis within the context of cardiac diseases. In this review, we systematically summarize the diverse phenotypic and functional plasticity of macrophages in regulatory mechanisms of cardiovascular diseases and unprecedented insights introduced by single-cell sequencing technologies, with a focus on different causes and characteristics of diseases, especially the relationship between inflammation and fibrosis in cardiac diseases (myocardial infarction, pressure overload, myocarditis, dilated cardiomyopathy, diabetic cardiomyopathy and cardiac aging) and the relationship between inflammation and vascular injury in vascular diseases (atherosclerosis and aneurysm). Finally, we also highlight the preclinical/clinical macrophage targeting strategies and translational implications.

Role of oncostatin-M in ECM remodeling and plaque vulnerability

Atherosclerosis is a multifactorial inflammatory disease characterized by the development of plaque formation leading to occlusion of the vessel and hypoxia of the tissue supplied by the vessel. Chronic inflammation and altered collagen expression render stable plaque to unstable and increase plaque vulnerability. Thinned and weakened fibrous cap results in plaque rupture and formation of thrombosis and emboli formation leading to acute ischemic events such as stroke and myocardial infarction. Inflammatory mediators including TREM-1, TLRs, MMPs, and immune cells play a critical role in plaque vulnerability. Among the other inflammatory mediators, oncostatin-M (OSM), a pro-inflammatory cytokine, play an important role in the development and progression of atherosclerosis, however, the role of OSM in plaque vulnerability and extracellular matrix remodeling (ECM) is not well understood and studied. Since ECM remodeling plays an important role in atherosclerosis and plaque vulnerability, a detailed investigation on the role of OSM in ECM remodeling and plaque vulnerability is critical. This is important because the role of OSM has been discussed in the context of proliferation of vascular smooth muscle cells and regulation of cytokine expression but the role of OSM is scarcely discussed in relation to ECM remodeling and plaque vulnerability. This review focuses on critically discussing the role of OSM in ECM remodeling and plaque vulnerability.

Transcription factors: key regulatory targets of vascular smooth muscle cell in atherosclerosis

Atherosclerosis (AS), leading to gradual occlusion of the arterial lumen, refers to the accumulation of lipids and inflammatory debris in the arterial wall. Despite therapeutic advances over past decades including intervention or surgery, atherosclerosis is still the most common cause of cardiovascular diseases and the main mechanism of death and disability worldwide. Vascular smooth muscle cells (VSMCs) play an imperative role in the occurrence of atherosclerosis and throughout the whole stages. In the past, there was a lack of comprehensive understanding of VSMCs, but the development of identification technology, including in vivo single-cell sequencing technology and lineage tracing with the CreERT2-loxP system, suggests that VSMCs have remarkable plasticity and reevaluates well-established concepts about the contribution of VSMCs. Transcription factors, a kind of protein molecule that specifically recognizes and binds DNA upstream promoter regions or distal enhancer DNA elements, play a key role in the transcription initiation of the coding genes and are necessary for RNA polymerase to bind gene promoters. In this review, we highlight that, except for environmental factors, VSMC genes are transcriptionally regulated through complex interactions of multiple conserved cis-regulatory elements and transcription factors. In addition, through a series of transcription-related regulatory processes, VSMCs could undergo phenotypic transformation, proliferation, migration, calcification and apoptosis. Finally, enhancing or inhibiting transcription factors can regulate the development of atherosclerotic lesions, and the downstream molecular mechanism of transcriptional regulation has also been widely studied.

Innate and adaptive immunity: the understudied driving force of heart valve disease

Calcific aortic valve disease (CAVD), and its clinical manifestation that is calcific aortic valve stenosis, is the leading cause for valve disease within the developed world, with no current pharmacological treatment available to delay or halt its progression. Characterized by progressive fibrotic remodelling and subsequent pathogenic mineralization of the valve leaflets, valve disease affects 2.5% of the western population, thus highlighting the need for urgent intervention. Whilst the pathobiology of valve disease is complex, involving genetic factors, lipid infiltration, and oxidative damage, the immune system is now being accepted to play a crucial role in pathogenesis and disease continuation. No longer considered a passive degenerative disease, CAVD is understood to be an active inflammatory process, involving a multitude of pro-inflammatory mechanisms, with both the adaptive and the innate immune system underpinning these complex mechanisms. Within the valve, 15% of cells evolve from haemopoietic origin, and this number greatly expands following inflammation, as macrophages, T lymphocytes, B lymphocytes, and innate immune cells infiltrate the valve, promoting further inflammation. Whether chronic immune infiltration or pathogenic clonal expansion of immune cells within the valve or a combination of the two is responsible for disease progression, it is clear that greater understanding of the immune systems role in valve disease is required to inform future treatment strategies for control of CAVD development.

Hydrogen sulfide prevents arterial medial calcification in rats with diabetic nephropathy

BACKGROUND

Arterial medial calcification (AMC) is associated with a high incidence of cardiovascular risk in patients with type 2 diabetes and chronic kidney disease. Here, we tested whether hydrogen sulfide (H2S) can prevent AMC in rats with diabetic nephropathy (DN).

METHODS

DN was induced by a single injection of streptozotocin and high-fat diet (45% kcal as fat) containing 0.75% adenine in Sprague-Dawley rats for 8 weeks.

RESULTS

Rats with DN displayed obvious calcification in aorta, and this was significantly alleviated by Sodium Hydrosulfide (NaHS, a H2S donor, 50 μmol/kg/day for 8 weeks) treatment through decreasing calcium and phosphorus content, ALP activity and calcium deposition in aorta. Interestingly, the main endogenous H2S generating enzyme activity and protein expression of cystathionine-γ-lyase (CSE) were largely reduced in the arterial wall of DN rats. Exogenous NaHS treatment restored CSE activity and its expression, inhibited aortic osteogenic transformation by upregulating phenotypic markers of smooth muscle cells SMα-actin and SM22α, and downregulating core binding factor α-1 (Cbfα-1, a key factor for bone formation), protein expressions in rats with DN when compared to the control group. NaHS administration also significantly reduced Stat3 activation, cathepsin S (CAS) activity and TGF-β1 protein level, and improved aortic elastin expression.

CONCLUSIONS

H2S may have a clinical significance for treating AMC in people with DN by reducing Stat3 activation, CAS activity, TGF-β1 level and increasing local elastin level.

Two-faced Janus: The dual role of macrophages in atherosclerotic calcification

Calcification is an independent predictor of atherosclerosis-related cardiovascular events. Microcalcification is linked to inflamed, unstable lesions, in comparison to the fibrotic stable plaque phenotype generally associated with advanced calcification. This paradox relates to recognition that calcification presents in a wide spectrum of manifestations that differentially impact plaque’s fate. Macrophages, the main inflammatory cells in atherosclerotic plaque, have a multifaceted role in disease progression. They crucially control the mineralization process, from microcalcification to the osteoid metaplasia of bone-like tissue. It is a bilateral interaction that weighs heavily on the overall plaque fate but remains rather unexplored. This review highlights current knowledge about macrophage phenotypic changes in relation to and interaction with the calcifying environment. On the one hand, macrophage-led inflammation kickstarts microcalcification through a multitude of interlinked mechanisms, which in turn stimulates phenotypic changes in vascular cell types to drive microcalcification. Macrophages may also modulate the expression/activity of calcification inhibitors and inducers, or eliminate hydroxyapatite nucleation points. Contrarily, direct exposure of macrophages to an early calcifying milieu impacts macrophage phenotype, with repercussions for plaque progression and/or stability. Macrophages surrounding macrocalcification deposits show a more reparative phenotype, modulating extracellular matrix, and expressing osteoclast genes. This phenotypic shift favours gradual displacement of the pro-inflammatory hubs; the lipid necrotic core, by macrocalcification. Parallels to bone metabolism may explain many of these changes to macrophage phenotype, with advanced calcification able to show homeostatic osteoid metaplasia. As the targeted treatment of vascular calcification developing in atherosclerosis is thus far severely lacking, it is crucial to better understand its mechanisms of development.

Oncostatin M is a novel biomarker for coronary artery disease - A possibility as a screening tool of silent myocardial ischemia for diabetes mellitus

Objective

Oncostatin M (OSM) is an inflammatory cytokine of the interleukin-6 family which plays a crucial role in the pathogenesis of atherosclerosis. Therefore, we tested our hypothesis that serum OSM levels are increased in patients with coronary artery diseases (CAD).

Methods and results

Serum OSM level was measured by sandwich technique immunoassay in 315 consecutive patients and who underwent coronary angiography at the International University of Health and Welfare Hospital from April 2019 to March 2021. A diagnosis of CAD was made in 169 patients. Serum OSM levels were significantly higher in patients with significant coronary stenosis compared to those without it. [123.0 ± 46.7 pg/mL (n = 169) vs. 98.3 ± 47.9 pg/mL (n = 146), p < 0.001]. A positive correlation was noted between serum OSM levels and severity and complexity of coronary stenosis. Importantly, the coronary revascularization significantly decreased the serum OSM levels. We furthermore detected a positive correlation between serum OSM levels and HbA1c levels. Finally, our data suggested that 120 pg/mL of serum OSM was the potential cutoff value for screening of silent myocardial ischemia related with diabetic mellitus (DM).

Conclusion

Serum OSM can be a novel biomarker for CAD and may be useful for the screening of asymptomatic CAD in patients with DM.

Macrophage Plasticity and Atherosclerosis Therapy

Atherosclerosis is a chronic disease starting with the entry of monocytes into the subendothelium and the subsequent differentiation into macrophages. Macrophages are the major immune cells in atherosclerotic plaques and are involved in the dynamic progression of atherosclerotic plaques. The biological properties of atherosclerotic plaque macrophages determine lesion size, composition, and stability. The heterogenicity and plasticity of atherosclerotic macrophages have been a hotspot in recent years. Studies demonstrated that lipids, cytokines, chemokines, and other molecules in the atherosclerotic plaque microenvironment regulate macrophage phenotype, contributing to the switch of macrophages toward a pro- or anti-atherosclerosis state. Of note, M1/M2 classification is oversimplified and only represent two extreme states of macrophages. Moreover, M2 macrophages in atherosclerosis are not always protective. Understanding the phenotypic diversity and functions of macrophages can disclose their roles in atherosclerotic plaques. Given that lipid-lowering therapy cannot completely retard the progression of atherosclerosis, macrophages with high heterogeneity and plasticity raise the hope for atherosclerosis regression. This review will focus on the macrophage phenotypic diversity, its role in the progression of the dynamic atherosclerotic plaque, and finally discuss the possibility of treating atherosclerosis by targeting macrophage microenvironment.

Construction and Validation of a New Model for the Prediction of Rupture in Patients with Intracranial Aneurysms

BACKGROUND

Despite progress in the detection of biological molecules that contribute to intracranial aneurysm (IA) development, many pathophysiological mechanisms remain unclear, particularly with regard to predicting IA rupture. In this study, we aimed to identify hub genes and construct a new model to predict IA rupture.

METHODS

Four datasets (62 ruptured IAs, 16 unruptured IAs, and 31 normal controls) were downloaded from the Gene Expression Omnibus. Differentially expressed genes (DEGs) were identified between the IAs and normal controls. All overlapping genes were analyzed using weighted gene co-expression network analysis. Functional enrichment analyses were performed using key modules. We then intersected the key module genes with DEGs. Protein-protein interaction networks were assessed to identify key hub genes. Least absolute shrinkage and selection operator logistic regression analysis was performed to construct a prediction model. A receiver operating characteristic curve was constructed to evaluate the reliability of the scoring system.

RESULTS

After intersection and normalization, 433 DEGs were identified and 15,388 genes were selected for weighted gene co-expression network analysis. The black module with 1145 genes exhibited the highest correlation with IA rupture. Many potential mechanisms are involved, such as the inflammatory response, innate immune response, extracellular exosome, and extracellular space. Thirty hub genes were selected from the protein-protein interaction, and 4 independent risk genes, TNFAIP6, NCF2, OSM, and IRAK3, were identified in the least absolute shrinkage and selection operator logistic regression model.

CONCLUSIONS

Our prediction model not only serves as a useful tool for assessing the risk of IA rupture, but the key genes identified herein could also serve as biomarkers and therapeutic targets.

Osteogenic differentiation and calcification of human aortic smooth muscle cells is induced by the RCN2/STAT3/miR-155-5p feedback loop

BACKGROUND

Vascular calcification (VC) is associated with the high morbidity and mortality of cardiovascular diseases in dialysis patients and is a process in which vascular smooth muscle cells (VSMCs) actively differentiate into osteoblast-like cells. Reticulocalbin-2 (RCN2) is involved in the process of osteogenic differentiation under diabetic conditions, but its regulatory role under hyperphosphatemic conditions and the related mechanisms remain unclear. In this study, the importance of the interactions among RCN2, STAT3 and miR-155-5p during the osteogenic differentiation and calcification of human aortic VSMCs (HASMCs) were investigated.

METHODS

RCN2 was measured in femoropopliteal artery plaque specimens from 6 peripheral arterial disease (PAD) patients with chronic kidney disease (CKD) and 6 PAD patients without CKD. RCN2 protein and mRNA expression were assessed in the high phosphate-induced aortic rings culture ex vivo model. In vitro calcification assays and molecular mechanism studies were performed in HASMCs.

RESULTS

Immunohistochemical staining results revealed increased RCN2 expression in the calcified plaques of femoral arteries of patients with CKD and in a high phosphate-induced aortic culture ex vivo model. RCN2 promoted HASMCs osteogenic differentiation and calcification by inducing STAT3 phosphorylation. Furthermore, inhibition of STAT3 activation by cryptotanshinone (CT) promoted miR-155-5p expression in HASMCs. In turn, miR-155-5p inhibited RCN2 mRNA expression, while RCN2 overexpression partially offset the miR-155-5p-mediated inhibition of HASMC calcification, acting as a positive feedback loop.

CONCLUSION

These results demonstrate that RCN2 is a crucial regulator of VC under hyperphosphatemic conditions. RCN2/STAT3/miR-155-5p feedback loop is important in VC and targeting each member of this feedback loop could potentially reverse high phosphate-induced VC.

Adipokines and Inflammation: Focus on Cardiovascular Diseases

It is well established that adipose tissue, apart from its energy storage function, acts as an endocrine organ that produces and secretes a number of bioactive substances, including hormones commonly known as adipokines. Obesity is a major risk factor for the development of cardiovascular diseases, mainly due to a low grade of inflammation and the excessive fat accumulation produced in this state. The adipose tissue dysfunction in obesity leads to an aberrant release of adipokines, some of them with direct cardiovascular and inflammatory regulatory functions. Inflammation is a common link between obesity and cardiovascular diseases, so this review will summarise the role of the main adipokines implicated in the regulation of the inflammatory processes occurring under the scenario of cardiovascular diseases.

JANEX-1 improves acute pulmonary embolism through VEGF and FAK in pulmonary artery smooth muscle cells

IMPACT STATEMENT

Accumulating evidence suggests that vascular remodeling due to immoderate proliferation and migration of SMCs is a common process occurring in APE. In this work, we tried to find a breakthrough in the pathological mechanism to alleviate the prognosis of APE by improving SMCs proliferation and explored the effect of JANEX-1 on PDGF-induced proliferation-related molecules in PVSMCs and assessed the therapeutic potential of JAK3 for vascular remodeling in APE mice. We demonstrated that JANEX-1, blocking JAK3 expression or activity, reduced JAK3/STAT3 signaling pathway, VEGF expression and FAK activation, and PDGF-induced proliferation of PVSMCs. Moreover, JANEX-1 inhibited the thrombus-induced intimal hyperplasia and the expression of VEGF and FAK activation in neointimal SMCs of APE mice. The data are helpful to elucidate the pharmacological mechanism and potential therapeutic effect of JANEX-1 in APE.

The Inhibitory Roles of Vitamin K in Progression of Vascular Calcification

Vitamin K is a fat-soluble vitamin that is indispensable for the activation of vitamin K-dependent proteins (VKDPs) and may be implicated in cardiovascular disease (CVD). Vascular calcification is intimately associated with CV events and mortality and is a chronic inflammatory process in which activated macrophages promote osteoblastic differentiation of vascular smooth muscle cells (VSMCs) through the production of proinflammatory cytokines such as IL-1β, IL-6, TNF-α, and oncostatin M (OSM) in both intimal and medial layers of arterial walls. This process may be mainly mediated through NF-κB signaling pathway. Vitamin K has been demonstrated to exert anti-inflammatory effects through antagonizing NF-κB signaling in both in vitro and in vivo studies, suggesting that vitamin K may prevent vascular calcification via anti-inflammatory mechanisms. Matrix Gla protein (MGP) is a major inhibitor of soft tissue calcification and contributes to preventing both intimal and medial vascular calcification. Vitamin K may also inhibit progression of vascular calcification by enhancing the activity of MGP through facilitating its γ-carboxylation. In support of this hypothesis, the procalcific effects of warfarin, an antagonist of vitamin K, on arterial calcification have been demonstrated in several clinical studies. Among the inactive MGP forms, dephospho-uncarboxylated MGP (dp-ucMGP) may be regarded as the most useful biomarker of not only vitamin K deficiency, but also vascular calcification and CVD. There have been several studies showing the association of circulating levels of dp-ucMGP with vitamin K intake, vascular calcification, mortality, and CVD. However, additional larger prospective studies including randomized controlled trials are necessary to confirm the beneficial effects of vitamin K supplementation on CV health.

IL-21 promotes osteoblastic differentiation of human valvular interstitial cells through the JAK3/STAT3 pathway

Objectives: This study amied to whether IL-21 promotes osteoblast transdifferentiation of cultured human Valvular interstitial cells (VICs). Methods: We first confirmed that IL-21 alters gene expression between CAVD aortic valve tissue and normal samples by immunohistochemistry, qPCR, and western blotting. VICs were cultured and treated with IL-21. Gene and protein expression levels of the osteoblastic markers ALP and Runx2, which can be blocked by specific JAK3 inhibitors and/or siRNA of STAT3, were measured. Results: IL-21 expression was upregulated in calcified aortic valves and promotes osteogenic differentiation of human VICs. IL-21 accelerated VIC calcification through the JAK3/STAT3 pathway. Conclusion: Our data suggest that IL-21 is a key factor in valve calcification and a promising candidate for targeted therapeutics for CAVD.

Oncostatin M reduces atherosclerosis development in APOE*3Leiden.CETP mice and is associated with increased survival probability in humans

Objective

Previous studies indicate a role for Oncostatin M (OSM) in atherosclerosis and other chronic inflammatory diseases for which inhibitory antibodies are in development. However, to date no intervention studies with OSM have been performed, and its relation to coronary heart disease (CHD) has not been studied.

Approach and results

Gene expression analysis on human normal arteries (n = 10) and late stage/advanced carotid atherosclerotic arteries (n = 127) and in situ hybridization on early human plaques (n = 9) showed that OSM, and its receptors, OSM receptor (OSMR) and Leukemia Inhibitory Factor Receptor (LIFR) are expressed in normal arteries and atherosclerotic plaques. Chronic OSM administration in APOE*3Leiden.CETP mice (n = 15/group) increased plasma E-selectin levels and monocyte adhesion to the activated endothelium independently of cholesterol but reduced the amount of inflammatory Ly-6C^High monocytes and atherosclerotic lesion size and severity. Using aptamer-based proteomics profiling assays high circulating OSM levels were shown to correlate with post incident CHD survival probability in the AGES‐Reykjavik study (n = 5457).

Conclusions

Chronic OSM administration in APOE*3Leiden.CETP mice reduced atherosclerosis development. In line, higher serum OSM levels were correlated with improved post incident CHD survival probability in patients, suggesting a protective cardiovascular effect.

Hydrogen Sulfide Prevents Elastin Loss and Attenuates Calcification Induced by High Glucose in Smooth Muscle Cells through Suppression of Stat3/Cathepsin S Signaling Pathway

Vascular calcification can be enhanced by hyperglycemia. Elastin loss in tunica media promotes the osteogenic transformation of smooth muscle cells (SMCs) and involves arterial medial calcification (AMC) that is associated with a high incidence of cardiovascular risk in patients with type 2 diabetes. Here, we tested whether hydrogen sulfide (H₂S), an endogenous gaseous mediator, can prevent elastin loss and attenuate calcification induced by high glucose in SMCs. Calcification was induced by high glucose (4500 mg/L) in human aortic SMCs (HASMCs) under the condition of calcifying medium containing 10 mM β-glycerophosphate (β-GP). The experiments showed that NaHS (an H₂S donor, 100 μM) mitigated the calcification of HASMCs treated with high glucose by decreasing calcium and phosphorus levels, calcium deposition and ALP activity and inhibited osteogenic transformation by increasing SMα-actin and SM22α, two phenotypic markers of smooth muscle cells, and decreasing core binding factor α-1 (Cbfα-1), a key factor in bone formation, protein expressions in HASMCs. Moreover, NaHS administration inhibited the activation of Stat3, cathepsin S (CAS) activity and its expression, but increased the level of elastin protein. Pharmacological inhibition or gene silencing Stat3 not only reversed elastin loss, but also attenuated CAS expression. Inhibition of CAS alleviated, while CAS overexpression exacerbated, elastin loss. Interestingly, overexpression of wild type (WT)-Stat3, but not its mutant C259S, elevated CAS protein expression and reduced elastin level. Moreover, NaHS induced S-sulfhydration in WT, but not in the C259S Stat3. These data suggest that H₂S may directly regulate Cys259 residue in Stat3 and then impair its signaling function. Our data indicate that H₂S may attenuate vascular calcification by upregulating elastin level through the inhibition of Stat3/CAS signaling.

Oncostatin M induces C2C12 myotube atrophy by modulating muscle differentiation and degradation

Oncostatin M (OSM) is a cytokine of the interleukin-6 family and plays a role in various disorders such as cancer and inflammatory diseases, which are often accompanied by skeletal muscle atrophy, or sarcopenia. However, the role of OSM in the regulation of skeletal muscle mass remains to be identified. In this study, we investigated the effect of OSM on C2C12 myotube formation in vitro. C2C12 myoblasts were induced to differentiate into myotubes for 3 days and then treated with OSM for 24 or 48 h. The diameter of differentiated C2C12 myotubes were reduced by 18.7% and 23.3% compared to control cells after treatment with OSM for 24 and 48 h, respectively. The expression levels of MyoD and myogenin were decreased, while those of atrogin-1, CCAAT/enhancer binding protein δ, and OSM receptor were increased in C2C12 myotubes treated with OSM for 24 h compared to control cells. Furthermore, the inhibitory effect of OSM on myotube formation was significantly attenuated by pretreatment with an inhibitor of signal transducer and activator of transcription (STAT) 3 or by knockdown of Stat3. Finally, the OSM-induced changes in the expression levels of MyoD, myogenin, and atrogin-1 were reversed by pretreatment with an inhibitor of STAT3 or by Stat3 knockdown in C2C12 myotubes. In conclusion, OSM induces C2C12 myotube atrophy by inhibiting myogenic differentiation and activating muscle degradation in a STAT3-dependent manner.

IL-6 and sIL-6R induces STAT3-dependent differentiation of human VSMCs into osteoblast-like cells through JMJD2B-mediated histone demethylation of RUNX2

Inflammation and vascular calcification are independent risk factors of cardiovascular events. Vascular smooth muscle cells (VSMCs) exhibit osteoblast-like characteristics in response to various stimuli such as oxidized cholesterol and inflammation. However the precise mechanism of transcriptional regulation of VSMCs by inflammatory stimuli remains unclear. We investigated the process and mechanisms of inflammatory cytokine-induced transformation of human VSMCs (hVSMCs) into osteoblast-like cells, with a special focus on epigenetic changes. Our results demonstrated: (1) interleukin-6 (IL-6)/soluble interleukin-6 receptor (sIL-6R) induced transformation of hVSMCs into an osteoblast phenotype, with subsequent vascular calcification, based on the results of Alizarin Red S staining and O-Cresolphthalein complexone method; (2) IL-6/sIL-6R accelerated the expression of runt-related transcription factor 2 (RUNX2) based on the results of quantitative real-time polymerase chain reaction; (3) Knockdown of signal transducer and activator of transcription (STAT) 3 reduced IL-6/sIL-6R-induced RUNX2 mRNA expression and osteoblast transdifferentiation of hVSMCs; (4) Chromatin immunoprecipitation (ChIP) coupled with PCR (ChIP-PCR) identified a STAT-binding site in RUNX2 promoter region containing trimethylated histone 3 lysine 9 (H3K9me3), a transcriptional repressor, and H3K4me3, a transcriptional enhancer. Stimulation with IL-6/sIL-6R suppressed H3K9me3 but not H3K4me3 through the recruitment of jumonji domain-containing protein (JMJD) 2B, a histone lysine demethylase, at the STAT-binding site in RUNX2 promoter region; (5) IL-6/sIL-6R-induced RUNX2 gene expression was inhibited in hVSMCs pretreated with JIB04, JMJD2 inhibitor, and the inhibitory effect was JIB04 dose-dependent. Our results indicate that the IL-6/STAT3/JMJD2B pathway regulates hVSMCs differentiation into osteoblast-like cells, which suggest its pathogenic role in vascular calcification associated with chronic inflammation.

Oncostatin M promotes the osteogenic differentiation of mouse MC3T3‑E1osteoblasts through the regulation of monocyte chemotactic protein‑1

The present study investigated the function of oncostatin M (OSM), which may be associated with monocyte chemotactic protein-1 (MCP-1), on mouse MC3T3-E1 osteoblast development and bone remodeling. Levels of MCP-1, macrophage inflammatory protein 1α (MIP1α) and regulated upon activation normal T cell expressed and secreted (RANTES) were measured by ELISA. Cell viability, migration and invasion abilities were detected by MTT, wound healing and Transwell assays, respectively. Western blotting was performed to detect levels of phosphorylated protein kinase B (Akt). Reverse transcription-quantitative polymerase chain reaction and western blotting were performed to detect the levels of matrix metalloproteinases (MMP)-1, −2 and −3. The results demonstrated that OSM treatment significantly increased MCP-1 levels in a dose-dependent manner. Interleukin (IL)-1, also significantly increased MCP-1 levels; however, treatment with other cytokines, including IL-6, IL-11 and leukemia inhibitory factor did not affect MCP-1 levels to the same extent. In addition, OSM did not affect levels of the chemokines MIP1α and RANTES; indeed, only IL-1 significantly increased levels of MIP1α and RANTES. OSM treatment promoted the proliferation, migration and invasion in a dose-dependent manner, which were inhibited by MCP-1 silencing. The expression of phosphorylated-Akt, MMP-1, −2 and −3 were increased by OSM treatment; however, these increases were reversed following MCP-1 silencing. Collectively these data suggest that OSM promotes the differentiation of mouse MC3T3-E1 osteoblasts via regulation of MCP-1 expression. These results may therefore provide novel insights into bone repair and remodeling.

Plaque Calcification During Atherosclerosis Progression and Regression

Plaque calcification develops by the inflammation-dependent mechanisms involved in progression and regression of atherosclerosis. Macrophages can undergo two distinct polarization states, that is, pro-inflammatory M1 phenotype in progression and anti-inflammatory M2 phenotype in regression. In plaque progression, predominant M1 macrophages promote the initial calcium deposition within the necrotic core of the lesions, called as microcalcification, through not only vesicle-mediated mineralization as the result of apoptosis of macrophages and vascular smooth muscle cells (VSMCs), but also VSMC differentiation into early phase osteoblasts. On the other hand, in plaque regression M2 macrophages are engaged in the healing response to plaque inflammation. In association with the resolution of chronic inflammation, M2 macrophages may facilitate macroscopic calcium deposition, called as macrocalcification, through induction of osteoblastic differentiation and maturation of VSMCs. Oncostatin M, which has been shown to promote osteoblast differentiation in bone, may play a pivotal role in the development of plaque calcification. Clinically, two types of plaque calcification have distinct implications. Macrocalcification leads to plaque stability, while microcalcification is more likely to be associated with plaque rupture. Statin therapy, which reduces cardiovascular mortality, has been shown to exert its dual actions on plaque morphology, that is, regression of atheroma and increment of macroscopic calcium deposits. Statins may facilitate the healing process against plaque inflammation by enhancing M2 polarization of macrophages. Vascular calcification has pleiotropic properties as pro-inflammatory “microcalcification” and anti-inflammatory “macrocalcification”. The molecular mechanisms of this process in relation with plaque progression as well as plaque regression should be intensively elucidated.

Janus Kinase 3, a Novel Regulator for Smooth Muscle Proliferation and Vascular Remodeling

OBJECTIVE

Vascular remodeling because of smooth muscle cell (SMC) proliferation is a common process occurring in several vascular diseases, such as atherosclerosis, aortic aneurysm, post-transplant vasculopathy, restenosis after angioplasty, etc. The molecular mechanism underlying SMC proliferation, however, is not completely understood. The objective of this study is to determine the role and mechanism of Janus kinase 3 (JAK3) in vascular remodeling and SMC proliferation.

APPROACH AND RESULTS

Platelet-derived growth factor-BB, an SMC mitogen, induces JAK3 expression and phosphorylation while stimulating SMC proliferation. Janex-1, a specific inhibitor of JAK3, or knockdown of JAK3 by short hairpin RNA, inhibits the SMC proliferation. Conversely, ectopic expression of JAK3 promotes SMC proliferation. Mechanistically, JAK3 promotes the phosphorylation of signal transducer and activator of transcription 3 and c-Jun N-terminal kinase in SMC, 2 signaling pathways known to be critical for SMC proliferation and vascular remodeling. Blockade of these 2 signaling pathways by their inhibitors impeded the JAK3-mediated SMC proliferation. In vivo, knockdown of JAK3 attenuates injury-induced neointima formation with attenuated neointimal SMC proliferation. Knockdown of JAK3 also induces neointimal SMC apoptosis in rat carotid artery balloon injury model.

CONCLUSIONS

Our results demonstrate that JAK3 mediates SMC proliferation and survival during injury-induced vascular remodeling, which provides a potential therapeutic target for preventing neointimal hyperplasia in proliferative vascular diseases.