Matrix metalloproteinase-10 deficiency delays atherosclerosis progression and plaque calcification

Identification of a functional missense variant in the matrix metallopeptidase 10 (MMP10) gene in two families with premature myocardial infarction

A positive family history is a major independent risk factor for atherosclerosis, and genetic variation is an important aspect of cardiovascular disease research. We identified a heterozygous missense variant p.L245P in the MMP10 gene in two families with premature myocardial infarction using whole-exome sequencing. The aim of this study was to investigate the consequences of this variant using in-silico and functional in-vitro assays. Molecular dynamics simulations were used to analyze protein interactions, calculate free binding energy, and measure the volume of the substrate-binding cleft of MMP10-TIMP1 models. The p.L245P variant showed an altered protein surface, different intra- and intermolecular interactions of MMP10-TIMP1, a lower total free binding energy between MMP10-TIMP1, and a volume-minimized substrate-binding cleft of MMP10 compared to the wild-type. For the functional assays, human THP-1 cells were transfected with plasmids containing MMP10 cDNA carrying the p.L245P and wild-type variant and differentiated into macrophages. Macrophage adhesion and migration assays were then conducted, and pro-inflammatory chemokine levels were evaluated. The p.L245P variant led to macrophages that were more adherent, less migratory, and secreted higher levels of the pro-inflammatory chemokines CXCL1 and CXCL8 than wild-type macrophages. Thus, the p.L245P variant in MMP10 may influence the pathogenesis of atherosclerosis in families with premature myocardial infarction by altering protein - protein interactions, macrophage adhesion and migration, and expression of pro-inflammatory chemokines, which may increase plaque rupture. These results could contribute to the development of selective MMP10 inhibitors and reduce the risk of atherosclerosis in families with a history of premature myocardial infarction.

The interplay of collagen, macrophages, and microcalcification in atherosclerotic plaque cap rupture mechanics

The rupture of an atherosclerotic plaque cap overlying a lipid pool and/or necrotic core can lead to thrombotic cardiovascular events. In essence, the rupture of the plaque cap is a mechanical event, which occurs when the local stress exceeds the local tissue strength. However, due to inter- and intra-cap heterogeneity, the resulting ultimate cap strength varies, causing proper assessment of the plaque at risk of rupture to be lacking. Important players involved in tissue strength include the load-bearing collagenous matrix, macrophages, as major promoters of extracellular matrix degradation, and microcalcifications, deposits that can exacerbate local stress, increasing tissue propensity for rupture. This review summarizes the role of these components individually in tissue mechanics, along with the interplay between them. We argue that to be able to improve risk assessment, a better understanding of the effect of these individual components, as well as their reciprocal relationships on cap mechanics, is required. Finally, we discuss potential future steps, including a holistic multidisciplinary approach, multifactorial 3D in vitro model systems, and advancements in imaging techniques. The obtained knowledge will ultimately serve as input to help diagnose, prevent, and treat atherosclerotic cap rupture.

Vascular smooth muscle cells in response to cholesterol crystals modulates inflammatory cytokines release and promotes neutrophil extracellular trap formation

BACKGROUND

The formation and accumulation of cholesterol crystals (CC) at the lesion site is a hallmark of atherosclerosis. Although studies have shown the importance of vascular smooth muscle cells (VSMCs) in the disease atherosclerosis, little is known about the molecular mechanism behind the uptake of CC in VSMCs and their role in modulating immune response.

METHODS

Human aortic smooth muscle cells were cultured and treated with CC. CC uptake and CC mediated signaling pathway and protein induction were studied using flow cytometry, confocal microscopy, western blot and Olink proteomics. Conditioned medium from CC treated VSMCs was used to study neutrophil adhesion, ROS production and phagocytosis. Neutrophil extracellular traps (NETs) formations were visualized using confocal microscopy.

RESULTS

VSMCs and macrophages were found around CC clefts in human carotid plaques. CC uptake in VSMCs are largely through micropinocytosis and phagocytosis via PI3K-AkT dependent pathway. The uptake of CC in VSMCs induce the release inflammatory proteins, including IL-33, an alarming cytokine. Conditioned medium from CC treated VSMCs can induce neutrophil adhesion, neutrophil reactive oxygen species (ROS) and neutrophil extracellular traps (NETs) formation. IL-33 neutralization in conditioned medium from CC treated VSMCs inhibited neutrophil ROS production and NETs formation.

CONCLUSION

We demonstrate that VSMCs due to its vicinity to CC clefts in human atherosclerotic lesion can modulate local immune response and we further reveal that the interaction between CC and VSMCs impart an inflammatory milieu in the atherosclerotic microenvironment by promoting IL-33 dependent neutrophil influx and NETs formation.

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.

LncRNA RP4-639F20.1 interacts with THRAP3 to attenuate atherosclerosis by regulating c-FOS in vascular smooth muscle cells proliferation and migration

BACKGROUND AND AIMS

The aberrant proliferation and migration of vascular smooth muscle cells (VSMCs) play an essential role in the pathogenesis of atherosclerosis (AS). Long noncoding RNAs (lncRNAs) have been reported as important regulators in a number of diseases. However, very little is known regarding the functional role of lncRNAs in governing proliferation and migration of VSMCs and AS development.

METHODS

Both in vitro and in vivo assays were performed to investigate the role of lncRNA in the pathophysiology of AS. Our previous lncRNA arrays revealed that lncRNA RP4-639F20.1 was significantly decreased in atherosclerotic plaques. Lentivirus overexpressing RP4-639F20.1 and lncRNA RP4-639F20.1 silencing vectors (Si-lnc-RP4-639F20.1) were constructed and transfected in VSMCs. The in vitro functions of lncRNA were analyzed by CCK-8 assays, EdU assays, scratch wound assays, transwell assays, qRT-PCR and Western blot analyses. RNA fluorescence in situ hybridization, immunoprecipitation and mRNA microarrays were used to explore the underlying mechanism. Adeno-associated-virus-9 (AAV9) overexpressing RP4-639F20.1 was constructed and injected intravenously into ApoE-/- mice to explore the role of lncRNA in vivo.

RESULTS

In vitro experiments showed that lncRNA RP4-639F20.1 interacted with THRAP3 and downregulated c-FOS expression. Both increase of lncRNA RP4-639F20.1 expression and knockdown of c-FOS inhibited the expression of MMP10 and VEGF-α in VSMCs and suppressed VSMCs proliferation and migration. In vivo experiments using ApoE-/- mice fed a high-fat diet demonstrated that lncRNA RP4-639F20.1 overexpression deterred atherosclerosis and decreased lipid levels in atherosclerotic lesions. Patients with coronary artery disease were found to have higher c-FOS levels than healthy individuals and c-FOS expression was positively correlated with the SYNTAX score of patients.

CONCLUSIONS

Overall, these data indicated that lncRNA RP4-639F20.1/THRAP3/c-FOS pathway protects against the development of atherosclerosis by suppressing VSMCs proliferation and migration. LncRNA RP4-639F20.1 and c-FOS could represent potential therapeutic targets to ameliorate atherosclerosis-related diseases.

The roles of MMP8/MMP10 polymorphisms in ischemic stroke susceptibility

BACKGROUND

Ischemic stroke (IS), a multifactorial and polygenic disease, is the most common cause of death. This study aimed to determine the roles of MMP8/MMP10 polymorphisms in IS susceptibility in the Chinese Han population.

METHODS

MMP8 rs1940475 and rs3765620, and MMP10 rs17860949 from 700 IS patients and 700 controls were genotyped by the MassARRAY iPLEX platform. The impact of polymorphisms on IS risk was evaluated by logistic regression analysis.

RESULTS

Our study indicated that rs17860949 in MMP10 was significantly associated with a reduced risk of IS (OR = 0.632, p = .002). Precisely, stratification analysis showed that rs17860949 was relate to a decreased susceptibility to IS in patients aged > 55 years (OR = 0.472, p < .001), males (OR = 0.632, p = .012), nonsmokers (OR = 0.610, p = .017), and nondrinkers (OR = 0.559, p = .006). All these significant findings were verified by false-positive report probability test. Furthermore, GG genotype and AG genotype in MMP8 rs3765620 polymorphism were related to a reduced triglycerides concentration (p = .018).

CONCLUSION

Our study suggests that rs17860949 in MMP10 may play a protective role in IS in the Chinese Han population.

Antigen-Presenting Cell-Like Neutrophils Foster T Cell Response in Hyperlipidemic Patients and Atherosclerotic Mice

Neutrophils constitute abundant cellular components in atherosclerotic plaques. Most of the current studies are focused on the roles of granular proteins released by neutrophils in atherosclerosis. Here, we revealed a unique subset of neutrophils which exhibit the characteristics of antigen-presenting cell (APC) (which were called APC-like neutrophils afterwards) in atherosclerosis. The roles of APC-like neutrophils and relevant mechanisms were investigated in hyperlipidemic patients and atherosclerotic mice. Higher percentages of neutrophils and APC-like neutrophils were found in peripheral blood of hyperlipidemic patients than that of healthy donors. Meanwhile, we also identified higher infiltration of neutrophils and APC-like neutrophils in atherosclerotic mice. Ox-LDL induced Phorbol-12-myristate-13-acetate (PMA)-activated neutrophils to acquire the APC-like phenotype. Importantly, upon over-expression of APC-like markers, neutrophils acquired APC functions to promote the proliferation and interferon-γ production of CD3⁺ T cells via HLA-DR/CD80/CD86. In accordance with what found in vitro, positive correlation between neutrophils and CD3⁺ T cells was observed in hyperlipidemic patients. In conclusion, our work identifies a proinflammatory neutrophil subset in both hyperlipidemic patients and atherosclerotic mice. This unique phenotype of neutrophils could activate the adaptive immune response to promote atherosclerosis progression. Thus, this neutrophil subset may be a new target for immunotherapy of atherosclerosis.

Novel Biomarkers of Atherosclerotic Vascular Disease-Latest Insights in the Research Field

The atherosclerotic vascular disease is a cardiovascular continuum in which the main role is attributed to atherosclerosis, from its appearance to its associated complications. The increasing prevalence of cardiovascular risk factors, population ageing, and burden on both the economy and the healthcare system have led to the development of new diagnostic and therapeutic strategies in the field. The better understanding or discovery of new pathophysiological mechanisms and molecules modulating various signaling pathways involved in atherosclerosis have led to the development of potential new biomarkers, with key role in early, subclinical diagnosis. The evolution of technological processes in medicine has shifted the attention of researchers from the profiling of classical risk factors to the identification of new biomarkers such as midregional pro-adrenomedullin, midkine, stromelysin-2, pentraxin 3, inflammasomes, or endothelial cell-derived extracellular vesicles. These molecules are seen as future therapeutic targets associated with decreased morbidity and mortality through early diagnosis of atherosclerotic lesions and future research directions.

Matrix Metalloproteinase-10 in Kidney Injury Repair and Disease

Matrix metalloproteinase-10 (MMP-10) is a zinc-dependent endopeptidase with the ability to degrade a broad spectrum of extracellular matrices and other protein substrates. The expression of MMP-10 is induced in acute kidney injury (AKI) and chronic kidney disease (CKD), as well as in renal cell carcinoma (RCC). During the different stages of kidney injury, MMP-10 may exert distinct functions by cleaving various bioactive substrates including heparin-binding epidermal growth factor (HB-EGF), zonula occludens-1 (ZO-1), and pro-MMP-1, -7, -8, -9, -10, -13. Functionally, MMP-10 is reno-protective in AKI by promoting HB-EGF-mediated tubular repair and regeneration, whereas it aggravates podocyte dysfunction and proteinuria by disrupting glomerular filtration integrity via degrading ZO-1. MMP-10 is also involved in cancerous invasion and emerges as a promising therapeutic target in patients with RCC. As a secreted protein, MMP-10 could be detected in the circulation and presents an inverse correlation with renal function. Due to the structural similarities between MMP-10 and the other MMPs, development of specific inhibitors targeting MMP-10 is challenging. In this review, we summarize our current understanding of the role of MMP-10 in kidney diseases and discuss the potential mechanisms of its actions.

Taxifolin improves inflammatory injury of human bronchial epithelial cells by inhibiting matrix metalloproteinase (MMP) 10 via Wnt/β-catenin pathway

Taxifolin (TXL), also known as dihydroquercetin, is one of the most important flavonoids prevalent across the plant kingdom. Increasing evidence has demonstrated its critical role in respiratory diseases. The present study aims to reveal the detailed mechanism in TNF-α-stimulated BEAS-2B cells by which TXL might exert effects on the development of asthma. Cell viability detection of BEAS-2B treated with TXL before and after TNF-α induction employed MMT. The expressions of inflammatory cytokines, MUC5AC and ICAM-1 were determined by quantitative reverse transcription PCR (RT-qPCR), enzyme-linked immunosorbent assay (ELISA) and Western blot after TXL was exposed to an in vitro asthma model. Then, light transmittance and apoptosis were then measured employing fluorescein transmittance, TUNEL and Western blot. After overexpressing MMP10, the abovementioned assays were performed again. Finally, the association between Wnt/β-catenin pathway and MMP10 was confirmed by detecting the proteins in this pathway. TXL increases the cell viability of TNF-induced BEAS-2B cells. TXL suppressed the inflammation, mucus formation, and apoptosis in TNF-α-induced BEAS-2B cells. Furthermore, after the prediction of binding sites between TXL and MMP10, it was found that overexpression of MMP10 reversed the effects of TXL on suppressing the progression of TNF-α-induced BEAS-2B cells. Finally, TXL blocked Wnt/β-catenin pathway by inhibiting MMP10 expression.

TXL can be a promising drug for the treatment of asthma due to its inhibition of MMP10 expression by blocking Wnt/β-catenin pathway. Future experimental in vivo studies of asthma on this commonly used bioactive flavonoid could open new avenues for the therapies of asthma.

Carotid Artery Plaque Calcifications: Lessons From Histopathology to Diagnostic Imaging

The role of calcium in atherosclerosis is controversial and the relationship between vascular calcification and plaque vulnerability is not fully understood. Although calcifications are present in ≈50% to 60% of carotid plaques, their association with cerebrovascular ischemic events remains unclear. In this review, we summarize current understanding of carotid plaque calcification. We outline the role of calcium in atherosclerotic carotid disease by analyzing laboratory studies and histopathologic studies, as well as imaging findings to understand clinical implications of carotid artery calcifications. Differences in mechanism of calcium deposition express themselves into a wide range of calcification phenotypes in carotid plaques. Some patterns, such as rim calcification, are suggestive of plaques with inflammatory activity with leakage of the vasa vasourm and intraplaque hemorrhage. Other patterns such as dense, nodular calcifications may confer greater mechanical stability to the plaque and reduce the risk of embolization for a given degree of plaque size and luminal stenosis. Various distributions and patterns of carotid plaque calcification, often influenced by the underlying systemic pathological condition, have a different role in affecting plaque stability. Modern imaging techniques afford multiple approaches to assess geometry, pattern of distribution, size, and composition of carotid artery calcifications. Future investigations with these novel technologies will further improve our understanding of carotid artery calcification and will play an important role in understanding and minimizing stroke risk in patients with carotid plaques.

Systems toxicology study reveals reduced impact of heated tobacco product aerosol extract relative to cigarette smoke on premature aging and exacerbation effects in aged aortic cells in vitro

Aging and smoking are major risk factors for cardiovascular diseases (CVD). Our in vitro study compared, in the context of aging, the effects of the aerosol of Tobacco Heating System 2.2 (THS; an electrically heated tobacco product) and 3R4F reference cigarette smoke (CS) on processes that contribute to vascular pathomechanisms leading to CVD. Young and old human aortic smooth muscle cells (HAoSMC) were exposed to various concentrations of aqueous extracts (AE) from 3R4F CS [0.014-0.22 puffs/mL] or THS aerosol [0.11-1.76 puffs/mL] for 24 h. Key markers were measured by high-content imaging, transcriptomics profiling and multianalyte profiling. In our study, in vitro aging increased senescence, DNA damage, and inflammation and decreased proliferation in the HAoSMCs. At higher concentrations of 3R4F AE, young HAoSMCs behaved similarly to aged cells, while old HAoSMCs showed additional DNA damage and apoptosis effects. At 3R4F AE concentrations with the maximum effect, the THS AE showed no significant effect in young or old HAoSMCs. It required an approximately ten-fold higher concentration of THS AE to induce effects similar to those observed with 3R4F. These effects were independent of nicotine, which did not show a significant effect on HAoSMCs at any tested concentration. Our results show that 3R4F AE accelerates aging in young HAoSMCs and exacerbates the aging effect in old HAoSMCs in vitro, consistent with CS-related contributions to the risk of CVD. Relative to 3R4F AE, the THS AE showed a significantly reduced impact on HAoSMCs, suggesting its lower risk for vascular SMC-associated pathomechanisms leading to CVD.

Matrix Metalloproteinase-7 Aggravated the Oxidized Low Density Lipoprotein-Induced Damage of Human Vascular Endothelial Cells

Introduction: Vascular endothelial injury could induce many cardiovascular diseases. Recently, some studies have indicated that matrix metalloproteinase-7 (MMP-7) was associated with the occurrence and development of cardiovascular diseases. However, whether higher levels of MMP-7 were associated with the occurrence of the vascular endothelial injury is unclear. Material and methods: In this study, ox-LDL was used for the simulation of vascular endothelial injury in HUVECs. Next, we detected the expression of MMP-7 in these cells. After that, we established the cell models with MMP-7 overexpression and knockdown, respectively. At last, the apoptosis and inflammation of HUVECs were detected with corresponding assays. Results: After the stimulation of ox-LDL, the expression of MMP-7 was enhanced compared to the control groups. After the stimulation of ox-LDL and the overexpression of MMP-7, the apoptosis rates of HUVECs were enhanced, while MMP-7 knockdown led to the decreased apoptosis rates of these cells. Furthermore, after the stimulation of ox-LDL and overexpression of MMP-7, the expression of inflammatory factors (IL-6, IL-1β and TNF-α) was promoted. Additionally, the expression of these proteins was repressed after knockdown of MMP-7. Conclusion: MMP-7 aggravated the ox-LDL-induced damage of HUVECs by promoting the apoptosis and inflammation of these cells.

MMP-10 rs17435959 Polymorphism is Associated with the Formation and Stability of Carotid Atherosclerosis Plaque: A Case-Control Study

BACKGROUND

Matrix metalloproteinase 10 (MMP-10) has a close relationship with carotid atherosclerosis (CAS) and cerebral infarction. The MMP-10 rs17435959 polymorphism causes a leucine to valine transition at codon 4 in exon 1 of the MMP-10 gene and may have functional effects.

OBJECTIVES

To investigate the relationship between the MMP-10 rs17435959 polymorphism and the formation and stability of CAS plaques.

MATERIALS AND METHODS

The present case-control study contains 738 visitors who came to our health examination center for the first time. According to the carotid ultrasound examinations, visitors were classified into the vulnerable plaque group (41-86 years old, 141 male, 105 female), the stable plaque group (41-86 years old, 141 male, 105 female) and the no plaque group (41-85 years old, 141 male, 105 female). All visitors in the three groups were sex- and- age-matched, and cardiovascular and cerebrovascular diseases were absent. The polymorphism was genotyped by real-time polymerase chain reaction- restriction.

RESULTS

Compared to the GG genotype, the frequency of the CC and CG genotypes was significantly more common in the vulnerable plaque group than in the no plaque group (18.7% vs. 7.7%, unadjusted P = 0.002). Moreover, compared to the G allele, the frequency of the C allele was significantly more common in the vulnerable plaque group than in the no plaque group (10.4% vs. 3.9%, unadjusted P = 0.000) and in the vulnerable plaque group than in the stable plaque group (10.4% vs. 5.1%, unadjusted P = 0.008). Binary logistic regression showed that the CC and CG genotype was independent risk factor for the formation (P = 0.019, OR = 1.961, 95% CI [1.117, 3.444]) and vulnerability (P = 0.035, OR = 1.842, 95% CI [1.045, 3.247]) of CAS plaques. Moreover, individuals who have the C allele showed a higher level of fibrinogen, which was an independent risk factor for the formation of CAS plaques (P = 0.000, OR = 2.425, 95% CI [1.475, 3.985]).

CONCLUSIONS

The rs17435959 polymorphism was associated with the formation and vulnerability of CAS plaques. Individuals who had variant-type MMP-10 showed higher levels of fibrinogen, which promoted the formation of CAS plaques.

Association of SDF1 and MMP12 with Atherosclerosis and Inflammation: Clinical and Experimental Study

BACKGROUND

Atherosclerosis is the main etiology of cardiovascular diseases (CVD), associated to systemic inflammation. Matrix metalloproteinases (MMPs) are related to atherosclerosis progression through the SDF1/CXCR4 axis promoting macrophages recruitment within the vascular wall. The goal was to assess new circulatory inflammatory markers in relation to atherosclerosis.

METHODS

Measurement of SDF1, MMP12 and CRP in blood samples of 298 prospective patients with cardiovascular risk. To explore atherosclerosis progression, CXCR4/SDF1 axis and MMP12 expression were determined by RT-qPCR and by immunohistochemistry in the aorta of accelerated and delayed atherosclerosis mice models (Apoe-/- and Apoe-/-Mmp10-/-).

RESULTS

SDF1, MMP12 and CRP were elevated in patients with clinical atherosclerosis, but after controlling by confounding factors, only SDF1 and CRP remained increased. Having high levels of both biomarkers showed 2.8-fold increased risk of presenting clinical atherosclerosis (p = 0.022). Patients with elevated SDF1, MMP12 and CRP showed increased risk of death in follow-up (HR = 3.2, 95%CI: 1.5-7.0, p = 0.004). Gene and protein expression of CXCR4 and MMP12 were increased in aortas from Apoe-/- mice.

CONCLUSIONS

The combination of high circulating SDF1, MMP12 and CRP identified patients with particular inflammatory cardiovascular risk and increased mortality. SDF1/CXCR4 axis and MMP12 involvement in atherosclerosis development suggests that they could be possible atherosclerotic targets.

The Role of Matrix Metalloproteinases in the Progression and Vulnerabilization of Coronary Atherosclerotic Plaques

Extracellular matrix (ECM) plays an important role in the development and progression of atherosclerotic lesions. Changes in the ECM are involved in the pathophysiology of many cardiovascular diseases, including atherosclerosis. Matrix metalloproteinases (MMPs) are a family of zinc-dependent proteases, also known as matrixins, with proteolytic activity in the ECM, being responsible for the process of tissue remodeling in various systemic pathologies, including cardiac and vascular diseases. MMPs play an important role in maintaining normal vascular structure, but also in secondary cardiovascular remodeling, in the formation of atherosclerotic plaques and in their vulnerabilization process. In addition to the assigned effect of MMPs in vulnerable plaques, they have a well-defined role in post-infarction ventricular remodeling and in various types of cardiomyopathies, followed by onset of congestive heart failure, with repeated hospitalizations and death. The aim of this manuscript was to provide a summary on the role of serum matrix metalloproteinases in the process of initiation, progression and complication of atherosclerotic lesions, from a molecular level to clinical applicability and risk prediction in patients with vulnerable coronary plaques.

Febuxostat, a Xanthine Oxidase Inhibitor, Decreased Macrophage Matrix Metalloproteinase Expression in Hypoxia

Macrophages in the atheroma region produce matrix metalloproteinases (MMPs) and decrease plaque stability. Tissue oxygen tension decreases in the arterial wall of the atherosclerotic region. Hypoxia inducible factor (HIF)-1α plays a critical role in the transcriptional activation of hypoxia inducible genes. However, the precise roles of HIF-1α independent pathways in hypoxic responses are largely unknown. Xanthine oxidase (XO) is an enzyme that utilizes molecular oxygen and produces reactive oxygen species (ROS). Here, we show that ROS derived from XO increases MMP-3, -10, and -13 expression in murine macrophages. We found that the transcript levels of macrophage MMP-3, -10, and -13 were increased in hypoxic conditions. Hypoxia induced MMP expression in HIF-1α deficient macrophages. N-acetylcysteine (NAC) or febuxostat, an XO inhibitor, suppressed MMP expression in murine macrophages. Febuxostat decreased the incidence of plaque rupture in apolipoprotein-E-deficient mice. Our results indicate that febuxostat stabilized atherosclerotic plaque via suppressing the activities of macrophage MMP-9 and -13. Febuxostat administration is a potential therapeutic option in the management of atherosclerotic patients.

Circulating TIMP-1 is associated with hematoma volume in patients with spontaneous intracranial hemorrhage

Matrix metalloproteinases (MMPs) are proteolytic zinc-endopeptidases regulated by tissue Inhibitors of matrix metalloproteinases (TIMPs). We evaluated the potential of MMPs and TIMPs as clinical tools for Intracranial Haemorrhage (ICH). Spontaneous non-traumatic ICH patients were recruited from two hospitals: Complejo Hospitalario de Navarra (CHN = 29) and Vall d´Hebron (VdH = 76). Plasmatic levels of MMP-1, -2, -7, -9, -10 and TIMP-1 and their relationship with clinical, radiological and functional variables were evaluated. We further studied the effect of TIMP-1 (0.05-0.2 mg/Kg) in an experimental tail-bleeding model. In CHN, TIMP-1 was associated with admission-hematoma volume and MMP-7 was elevated in patients with deep when compared to lobar hematoma. In VdH, admission-hematoma volume was associated with TIMP-1 and MMP-7. When data from both hospitals were combined, we observed that an increase in 1 ng/ml in TIMP-1 was associated with an increase of 0.14 ml in haemorrhage (combined β = 0.14, 95% CI = 0.08-0.21). Likewise, mice receiving TIMP-1 (0.2 mg/Kg) showed a shorter bleeding time (p < 0.01). Therefore, the association of TIMP-1 with hematoma volume in two independent ICH cohorts suggests its potential as ICH biomarker. Moreover, increased TIMP-1 might not be sufficient to counterbalance MMPs upregulation indicating that TIMP-1 administration might be a beneficial strategy for ICH.

Matrix Metalloproteinases as Biomarkers of Atherosclerotic Plaque Instability

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases responsible for tissue remodeling and degradation of extracellular matrix (ECM) proteins. MMPs may modulate various cellular and signaling pathways in atherosclerosis responsible for progression and rupture of atherosclerotic plaques. The effect of MMPs polymorphisms and the expression of MMPs in both the atherosclerotic plaque and plasma was shown. They are independent predictors of atherosclerotic plaque instability in stable coronary heart disease (CHD) patients. Increased levels of MMPs in patients with advanced cardiovascular disease (CAD) and acute coronary syndrome (ACS) was associated with future risk of cardiovascular events. These data confirm that MMPs may be biomarkers in plaque instability as they target in potential drug therapies for atherosclerosis. They provide important prognostic information, independent of traditional risk factors, and may turn out to be useful in improving risk stratification.

Role of Macrophages in the Progression and Regression of Vascular Calcification

Vascular calcification is an abnormal cell-mediated process in which bone-specific hydroxyapatite crystals are actively deposited on the blood vessel wall and is a significant pathological basis for the increased incidence and mortality of adverse cardiovascular events. Macrophages play an important regulatory role in the occurrence, development, and regression of vascular calcification. After the tissue microenvironment changes, macrophages subsequently change their polarity and phenotype or secrete functional substances as an adaptive response. As research on macrophages continue to move into this field, we gain a new understanding of the mechanism of the formation and regression of vascular calcification, which might offer valuable new intervention targets for the prevention and inhibition of vascular calcification. This review summarizes a wealth of research in this field and explores the roles of macrophages in the development process of vascular calcification.

The biology of vascular calcification

Vascular calcification (VC), characterized by different mineral deposits (i.e., carbonate apatite, whitlockite and hydroxyapatite) accumulating in blood vessels and valves, represents a relevant pathological process for the aging population and a life-threatening complication in acquired and in genetic diseases. Similarly to bone remodeling, VC is an actively regulated process in which many cells and molecules play a pivotal role. This review aims at: (i) describing the role of resident and circulating cells, of the extracellular environment and of positive and negative factors in driving the mineralization process; (ii) detailing the types of VC (i.e., intimal, medial and cardiac valve calcification); (iii) analyzing rare genetic diseases underlining the importance of altered pyrophosphate-dependent regulatory mechanisms; (iv) providing therapeutic options and perspectives.

Intravenous antagomiR-494 lessens brain-infiltrating neutrophils by increasing HDAC2-mediated repression of multiple MMPs in experimental stroke

Neutrophil infiltration and phenotypic transformation are believed to contribute to neuronal damage in ischemic stroke. Emerging evidence suggests that histone deacetylase 2 (HDAC2) is an epigenetic regulator of inflammatory cells. Here, we aimed to investigate whether microRNA-494 (miR-494) affects HDAC2-mediated neutrophil infiltration and phenotypic shift. MiR-494 levels in neutrophils from acute ischemic stroke (AIS) patients were detected by real-time PCR. Chromatin Immunoprecipitation (ChIP)-Seq was performed to clarify which genes are the binding targets of HDAC2. Endothelial cells and cortical neurons were subjected to oxygen-glucose deprivation (OGD), transwell assay was conducted to examine neutrophil migration through endothelial cells, and neuronal injury was examined after stimulating with supernatant from antagomiR-494-treated neutrophils. C57BL/6J mice were subjected to transient middle cerebral artery occlusion (MCAO) and antagomiR-494 was injected through tail vein immediately after reperfusion, and neutrophil infiltration and phenotypic shift was examined. We found that the expression of miR-494 in neutrophils was significantly increased in AIS patients. HDAC2 targeted multiple matrix metalloproteinases (MMPs) and Fc-gamma receptor III (CD16) genes in neutrophils of AIS patients. Furthermore, antagomiR-494 repressed expression of multiple MMPs genes, including MMP7, MMP10, MMP13, and MMP16, which reduced the number of brain-infiltrating neutrophils by regulating HDAC2. AntagomiR-494 could also exert its neuroprotective role through inhibiting the shift of neutrophils toward pro-inflammatory N1 phenotype in vivo and in vitro. Taken together, miR-494 may serve as an alternative predictive biomarker of the outcome of AIS patients, and antagomiR-494 treatment decreases the expression of multiple MMPs and the infiltration of neutrophils and inhibits the shift of neutrophils into N1 phenotype partly by targeting HDAC2.

A Role for MMP-10 (Matrix Metalloproteinase-10) in Calcific Aortic Valve Stenosis

OBJECTIVE

Aortic valve (AV) calcification plays an important role in the progression of aortic stenosis (AS). MMP-10 (matrix metalloproteinase-10 or stromelysin-2) is involved in vascular calcification in atherosclerosis. We hypothesize that MMP-10 may play a pathophysiological role in calcific AS. Approach and Results: Blood samples (n=112 AS and n=349 controls) and AVs (n=88) from patients undergoing valve replacement were analyzed. Circulating MMP-10 was higher in patients with AS compared with controls (P<0.001) and correlated with TNFα (tumor necrosis factor α; r_S=0.451; P<0.0001). MMP-10 was detected by immunochemistry in AVs from patients with AS colocalized with aortic valve interstitial cells markers α-SMA (α-smooth muscle actin) and vimentin and with calcification markers Runx2 (Runt-related transcription factor 2) and SRY (sex-determining region Y)-box 9. MMP-10 expression in AVs was further confirmed by RT-qPCR and western blot. Ex vivo, MMP-10 was elevated in the conditioned media of AVs from patients with AS and associated with interleukin-1β (r_S=0.5045, P<0.001) and BMP (bone morphogenetic protein)-2 (r_S=0.5003, P<0.01). In vitro, recombinant human MMP-10 induced the overexpression of inflammatory, fibrotic, and osteogenic markers (interleukin-1β, α-SMA, vimentin, collagen, BMP-4, Sox9, OPN [osteopontin], BMP-9, and Smad 1/5/8; P<0.05) and cell mineralization in aortic valve interstitial cells isolated from human AVs, in a mechanism involving Akt (protein kinase B) phosphorylation. These effects were prevented by TIMP-1 (tissue inhibitor of metalloproteinases type 1), a physiological MMP inhibitor, or specifically by an anti-MMP-10 antibody.

CONCLUSIONS

MMP-10, which is overexpressed in aortic valve from patients with AS, seems to play a central role in calcification in AS through Akt phosphorylation. MMP-10 could be a new therapeutic target for delaying the progression of aortic valve calcification in AS.

Innate and adaptive immunity in cardiovascular calcification

Despite the focus placed on cardiovascular research, the prevalence of vascular and valvular calcification is increasing and remains a leading contributor of cardiovascular morbidity and mortality. Accumulating studies provide evidence that cardiovascular calcification is an inflammatory disease in which innate immune signaling becomes sustained and/or excessive, shaping a deleterious adaptive response. The triggering immune factors and subsequent inflammatory events surrounding cardiovascular calcification remain poorly understood, despite sustained significant research interest and support in the field. Most studies on cardiovascular calcification focus on innate cells, particularly macrophages' ability to release pro-osteogenic cytokines and calcification-prone extracellular vesicles and apoptotic bodies. Even though substantial evidence demonstrates that macrophages are key components in triggering cardiovascular calcification, the crosstalk between innate and adaptive immune cell components has not been adequately addressed. The only therapeutic options currently used are invasive procedures by surgery or transcatheter intervention. However, no approved drug has shown prophylactic or therapeutic effectiveness. Conventional diagnostic imaging is currently the best method for detecting, measuring, and assisting in the treatment of calcification. However, these common imaging modalities are unable to detect early subclinical stages of disease at the level of microcalcifications; therefore, the vast majority of patients are diagnosed when macrocalcifications are already established. In this review, we unravel the current knowledge of how innate and adaptive immunity regulate cardiovascular calcification; and put forward differences and similarities between vascular and valvular disease. Additionally, we highlight potential immunomodulatory drugs with the potential to target calcification and propose avenues in need of further translational inquiry.

MMP2 and MMP10 Polymorphisms Are Related to Steroid-Induced Osteonecrosis of the Femoral Head among Chinese Han Population

Background

Steroid-induced osteonecrosis of the femoral head is a relatively serious condition which seriously reduces patient quality of life. However, the pathogenesis of steroid-induced ONFH is still unclear. In recent years, more scholars have found that the pathogenesis of steroid-induced ONFH is related to susceptibility factors such as MMPs/TIMPs system. The main purpose of this study is to investigate the correlation between MMP2 and MMP10 gene polymorphisms and steroid-induced ONFH in Chinese Han population.

Methods

Six SNPs in MMP2 and two SNPs in MMP10 were genotyped using Agena MassARRAY RS1000 system from 286 patients of steroid-induced ONFH and in 309 healthy controls. The association between MMP2 and MMP10 polymorphisms and steroid-induced ONFH risk were estimated by the Chi-squared test, genetic model analysis, haplotype analysis, and stratification analysis. The relative risk was estimated by odd ratios (ORs) and 95% confidence intervals (CIs).

Result

We found that the minor TG allele of rs470154 in MMP10 was associated with an increased risk of steroid-induced ONFH (OR = 1.45, 95% CI, 1.03 – 2.05, p = 0.032). In the genetic model analysis, we found that rs2241146 in MMP2 gene and rs470154 in MMP10 gene showed a statistically significant association with increased risk of steroid-induced ONFH. The six SNPs (rs470154, rs243866, rs243864, rs865094, rs11646643, and rs2241146) showed a statistically significant association with different clinical phenotypes.

Conclusion

Our results verify that genetic polymorphisms of MMP2 and MMP10 contribute to steroid-induced ONFH susceptibility in the population of Chinese Han population, and our study provides new insights into the role that MMP2 and MMP10 plays in the mechanism of ONFH.

Identification of Candidate Genes Involved in Renal Ischemia/Reperfusion Injury

Renal ischemia/reperfusion injury (IRI) is a main risk factor for the occurrence of delayed graft function or primary graft nonfunction of kidney transplantation. However, it lacks ideal molecular markers for indicating IRI in kidney transplantation. The present study is to explore novel candidate genes involved in renal IRI. Experimental renal IRI mouse models were constructed, and the differentially expressed genes were screened using a microarray assay. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were performed. The expression of genes was detected using real-time qPCR assay. Western blotting and immunohistochemistry staining assays were performed for protein determination. We identified that renal IRI induced the upregulation of SPRR2F, SPRR1A, MMP-10, and long noncoding RNA (lncRNA) Malat1 in kidney tissues for 479.3-, 4.98-, 238.1-, and 3.79-fold, respectively. The expression of miR-139-5p in kidney tissues of IRI-treated mice was decreased to 40.4% compared with the sham-operated mice. These genes are associated with keratinocyte differentiation, regeneration and repair of kidney tissues, extracellular matrix degradation and remodeling, inflammation, and cell proliferation in renal IRI. Identification of novel biomarkers involved in renal IRI may provide evidences for the diagnosis and treatment of renal IRI.