Monocytes enhance the inflammatory response to TLR2 stimulation in aortic valve interstitial cells through paracrine up-regulation of TLR2 level

Age-associated methionine sulfoxide reductase A protects against valvular interstitial cell senescence and valvular calcification

Calcific aortic valve disease (CAVD) is a cardiovascular disease prevalent in the aging population, resulting in high morbidity and mortality rates. However, the molecular mechanisms underlying CAVD remain unclear. We initially conducted an RNA sequencing analysis of aortic valve leaflets from rats of different ages to identify key genes involved in valvular aging and calcification. Bioinformatics analysis demonstrated that methionine sulfoxide reductase A (MSRA) was crucial to valvular calcification and senescence. To further investigate whether and how MSRA influences CAVD pathogenesis, we utilized two in vitro models: a human valvular interstitial cell (VIC) calcification model induced by osteogenic medium, and a VIC senescence model induced by hydrogen peroxide. Western blotting, immunofluorescence, flow cytometry, and alkaline phosphatase staining were conducted to evaluate the changes in calcific nodule formation and senescent markers. In vivo, ApoE-/- mice were treated either a normal chow or a high-cholesterol chow to determine the effects of MSRA overexpression on aortic valve calcification and senescence. MSRA silencing increased the osteogenic differentiation and senescence of VIC, whereas its overexpression produced the opposite effects. Similarly, we found that MSRA overexpression reduced calcium deposition and decreased the levels of senescent markers in ApoE-/- mice. Further mechanism experiments showed that MSRA suppressed osteoblastic differentiation via inhibiting the toll-like receptor (TLR2)/nuclear factor-κB (NF-κB) pathway. Our findings demonstrate that MSRA ameliorates valvular calcification and senescence by inhibiting TLR2/NF-κB pathway, highlighting MSRA as a promising target for treating age-associated CAVD.

Adjustment of the Framingham index by abdominal aortic calcification scores enables a more accurate prediction of long-term cardiac events in general population aged 40 years and above: evidence from NHANES 2013-2014

BACKGROUND

Abdominal aortic calcification (AAC) is considered as a strong predictor of cardiovascular disease (CVD) events. Our study aimed to investigate whether the predicted risk for cardiac death with the Framingham risk score (FRS) could be further improved with the addition of AAC score in general population aged ≥ 40 years.

METHODS

A total of 2971 participants aged ≥ 40 years in the National Health and Nutrition Examination Surveys (NHANES) 2013-2014 were followed up. The Spearman's rank correlation was performed to explore the correlation between the AAC score and FRS. the Kaplan-Meier method was used to make cumulative cardiac death curve. Predictors of cardiac death was identified by multivariate Cox regression. Additionally, the predictive value of FRS alone and combined with AAC score was estimated by comparing the area under the receiver-operating characteristic (ROC) curve (AUC) and calculating Integrated Discrimination Improvement (IDI).

RESULTS

During a median of 70.50 months (interquartile range 58.43-82.57 months), 49 (1.649%) experienced cardiac death in the follow-up. The FRS was positively associated with AAC score. Both FRS and AAC score were independent predictors of cardiac death (hazard ratio 1.216; 95%CI 1.135 to 1.302; p < 0.00001; 1.159; 95%CI 1.109 to 1.211; p < 0.00001; respectively). Furthermore, Kaplan-Meier analysis demonstrated increased risk of cardiac death with increasing AAC score (log-rank 54.548, p<0.0001). The predictive value of FRS significantly was improved by adding with AAC score [increase in AUC from 0.734 to 0.780, p < 0.0001; IDI = 0.007, p = 0.013 ].

CONCLUSIONS

AAC score is positively related with Framingham index, and FBS adjusted by AAC score further improved the prediction risk for cardiac death in general population aged ≥ 40 years.

Macrophages in Calcific Aortic Valve Disease: Paracrine and Juxtacrine Disease Drivers

A significant role in the pathogenesis of CAVD is played by innate immunity cells, such as macrophages. In stenotic valves, macrophages have enhanced inflammatory activity, and the population's balance is shifted toward pro-inflammatory ones. Pro-inflammatory macrophages release cytokines, chemokines, and microRNA, which can directly affect the resident valvular cells and cause valve calcification. In CAVD patients, macrophages may have more pronounced pro-inflammatory properties, enhanced not only by paracrine signals but also by juxtacrine Notch signaling and epigenetic factors, which influence the maturation of macrophages' progenitors. In this review, we observe the accumulated data on the involvement of macrophages in CAVD development via paracrine and juxtacrine interactions.

Saponins of Paris polyphylla for the Improvement of Acne: Anti-Inflammatory, Antibacterial, Antioxidant and Immunomodulatory Effects

Acne is a chronic inflammatory skin disease with a recurring nature that seriously impacts patients' quality of life. Currently, antibiotic resistance has made it less effective in treating acne. However, Paris polyphylla (P. polyphylla) is a valuable medicinal plant with a wide range of chemical components. Of these, P. polyphylla saponins modulate the effects in vivo and in vitro through antibacterial, anti-inflammatory, immunomodulatory, and antioxidant effects. Acne is primarily associated with inflammatory reactions, abnormal sebum function, micro-ecological disorders, hair follicle hyperkeratosis, and, in some patients, immune function. Therefore, the role of P. polyphylla saponins and their values in treating acne is worthy of investigation. Overall, this review first describes the distribution and characteristics of P. polyphylla and the pathogenesis of acne. Then, the potential mechanisms of P. polyphylla saponins in treating acne are listed in detail (reduction in the inflammatory response, antibacterial action, modulation of immune response and antioxidant effects, etc.). In addition, a brief description of the chemical composition of P. polyphylla saponins and its available extraction methods are described. We hope this review can serve as a quick and detailed reference for future studies on their potential acne treatment.

Association between urinary biomarkers of polycyclic aromatic hydrocarbons and severe abdominal aortic calcification in adults: data from the National Health and Examination Nutrition Survey

OBJECTIVE

Recent studies have found that polycyclic aromatic hydrocarbons (PAHs) exposure may increase the risk of cardiovascular disease. The present study aimed to explore the association between PAHs exposure and severe abdominal aortic calcification (AAC) in adults.

METHODS

Data were collected from the 2013-2014 National Health and Nutrition Examination Survey. PAHs exposure was analyzed from urinary mono hydroxylated metabolites of PAHs. Logistic regression models and subgroup analysis were performed to explore the association of PAHs exposure with severe AAC prevalence.

RESULTS

A total of 1,005 eligible individuals were recruited into the study. After adjusting for confounding factors, those with the highest quartiles of 1-hydroxynaphthalene (1-NAP: OR 2.19, 95% CI 1.03-4.68, P_{for trend} < 0.001), 2-hydroxynaphthalene (2-NAP: OR 2.22, 95% CI 1.04-4.64, P_{for trend} < 0.001) and 1-hydroxypyrene (1-PYR: OR 2.15, 95% CI 1.06-4.33, P_{for trend} < 0.001) were associated with an increased prevalence of severe AAC in the adults compared to those who in the lowest quartile.

CONCLUSION

This study found that urinary 1-NAP, 2-NAP and 1-PYR were positively associated with severe AAC prevalence in adults.

Identification of key genes involved in calcific aortic valve disease based on integrated bioinformatics analysis

The calcific aortic valve disease (CAVD) develops as an aortic valve sclerosis and progresses to an advanced form of stenosis. In many biological fields, bioinformatics becomes a fundamental component. The key mechanisms involved in CAVD are discovered with the use of bioinformatics to investigate gene function and pathways. We downloaded the original data (GSE51472) from the Gene Expression Omnibus (GEO) database (http://www.ncbi.nlm.nih.gov/geo/). After standardization, 2978 differentially expressed genes (DEGs) were identified from the data sets GSE51472 containing samples from normal, calcified, and sclerotic aortic valves. Analysis of DEGs based on the series test of clusters (STCs) revealed the two most significant patterns. Based on the result of the STC, the functional enrichment analysis of gene ontology (GO) was conducted to investigate the molecular function (MF), biological process (BP), and cell compound (CC) of the DEGs. With a p value of 0.01, DEGs associated with "chronic inflammation," "T-cell receptor complexes," and "antigen binding" had the highest significance within BP, CC, and MF. DEG enrichment in signaling pathways was analyzed using KEGG pathway enrichment. Using a p < 0.05 level of significance, the most enriched biological pathways related to CAVD were "Chemokine signaling pathway," "Cytokine-cytokine receptor interaction," "Tuberculosis," "PI3K-Akt signaling pathway," and "Transcriptional misregulation in cancer." Finally, the construction of gene co-expression networks and pathway networks illustrated the pathogensis of CAVD. TLR2, CD86, and TYROBP were identified as hub genes for the development of CAVD. Moreover, "MAPK signaling pathway," "Apoptosis," and "Pathways in cancer" were regarded as the core pathways among the samples of normal, sclerotic and calcified aortic valve samples.

Relation of Monocyte Number to Progression of Aortic Stenosis

Rapid progression of aortic stenosis (AS) is associated with poor prognosis. However, the relation between monocyte number and AS progression is unknown. Here, we detected the relation between monocyte number and AS progression. We retrospectively analyzed 220 patients with AS with at least 2 echocardiograms with the maximal interval ≥180 days from January 2016 to June 2021. AS severity was categorized by aortic jet velocity (V_max) and mean pressure gradient. Rapid progression of AS was defined when V_max increased ≥0.3 m/s/year. Patients were divided into low and high monocyte groups according to the cut-off value of the receiver-operating characteristic curve. AS progression was compared between the 2 groups. Various models of binary logistic regression were used to reveal the association between monocyte number and rapid progression. During a median of 601 days of echocardiographic follow-up (interquartile range 353 to 909), 52.7% of the population was in rapid progression. Patients in the high monocyte group had more rapid progression in both V_max and mean pressure gradient (p = 0.020 and p = 0.030, respectively). The percentage of patients with severe AS was increased by 5.4% in the low monocyte group and 16.9% in the high monocyte group. Different models of binary logistic regression showed that the monocyte number was positively associated with the rapid progression. In conclusion, a higher monocyte number was associated with the rapid progression of AS.

Monocytes augment inflammatory responses in human aortic valve interstitial cells via β2-integrin/ICAM-1-mediated signaling

OBJECTIVE

Inflammatory infiltration in aortic valves promotes calcific aortic valve disease (CAVD) progression. While soluble extracellular matrix (ECM) proteins induce inflammatory responses in aortic valve interstitial cells (AVICs), the impact of monocytes on AVIC inflammatory responses is unknown. We tested the hypothesis that monocytes enhance AVIC inflammatory responses to soluble ECM protein in this study.

METHODS

Human AVICs isolated from normal aortic valves were cocultured with monocytes and stimulated with soluble ECM protein (matrilin-2). ICAM-1 and IL-6 productions were assessed. YAP and NF-κB phosphorylation were analyzed. Recombinant CD18, neutralizing antibodies against β₂-integrin or ICAM-1, and inhibitor of YAP or NF-κB were applied.

RESULTS

AVIC expression of ICAM-1 and IL-6 was markedly enhanced by the presence of monocytes, although matrilin-2 did not affect monocyte production of ICAM-1 or IL-6. Matrilin-2 up-regulated the expression of monocyte β₂-integrin and AVIC ICAM-1, leading to monocyte-AVIC adhesion. Neutralizing β₂-integrin or ICAM-1 in coculture suppressed monocyte adhesion to AVICs and the expression of ICAM-1 and IL-6. Recombinant CD18 enhanced the matrilin-2-induced ICAM-1 and IL-6 expression in AVIC monoculture. Further, stimulation of coculture with matrilin-2 induced greater YAP and NF-κB phosphorylation. Inhibiting either YAP or NF-κB markedly suppressed the inflammatory response to matrilin-2 in coculture.

CONCLUSION

Monocyte β₂-integrin interacts with AVIC ICAM-1 to augment AVIC inflammatory responses to soluble matrilin-2 through enhancing the activation of YAP and NF-κB signaling pathways. Infiltrated monocytes may promote valvular inflammation through cell-cell interaction with AVICs to enhance their sensitivity to damage-associated molecular patterns.

Pro-inflammatory mediators released by activated monocytes promote aortic valve fibrocalcific activity

Background

Calcific aortic valve disease (CAVD) is the most prevalent heart valve disorder in the elderly. Valvular fibrocalcification is a characteristic pathological change. In diseased valves, monocyte accumulation is evident, and aortic valve interstitial cells (AVICs) display greater fibrogenic and osteogenic activities. However, the impact of activated monocytes on valular fibrocalcification remains unclear. We tested the hypothesis that pro-inflammatory mediators from activated monocytes elevate AVIC fibrogenic and osteogenic activities.

Methods and results

Picro-sirius red staining and Alizarin red staining revealed collagen and calcium depositions in cultured human AVICs exposed to conditioned media derived from Pam3CSK4-stimulated monocytes (Pam3 CM). Pam3 CM up-regulated alkaline phosphatase (ALP), an osteogenic biomarker, and extracellular matrix proteins collagen I and matrix metalloproteinase-2 (MMP-2). ELISA analysis identified high levels of RANTES and TNF-α in Pam3 CM. Neutralizing RANTES in the Pam3 CM reduced its effect on collagen I and MMP-2 production in AVICs while neutralizing TNF-α attenuated the effect on AVIC ALP production. In addition, Pam3 CM induced NF-κB and JNK activation. While JNK mediated the effect of Pam3 CM on collagen I and MMP-2 production, NF-κB was critical for the effect of Pam3 CM on ALP production in AVICs.

Conclusions

This study demonstrates that activated monocytes elevate the fibrogenic and osteogenic activities in human AVICs through a paracrine mechanism. TNF-α and RANTES mediate the pro-fibrogenic effect of activated monocytes on AVICs through activation of JNK, and TNF-α also activates NF-κB to elevate AVIC osteogenic activity. The results suggest that infiltrated monocytes elevate AVIC fibrocalcific activity to promote CAVD progression.

Innate immune cells in the pathophysiology of calcific aortic valve disease: lessons to be learned from atherosclerotic cardiovascular disease?

Calcific aortic valve disease (CAVD) is the most common valvular disease in the developed world with currently no effective pharmacological treatment available. CAVD results from a complex, multifactorial process, in which valvular inflammation and fibro-calcific remodelling lead to valve thickening and cardiac outflow obstruction. The exact underlying pathophysiology of CAVD is still not fully understood, yet the development of CAVD shows many similarities with the pathophysiology of atherosclerotic cardiovascular disease (ASCVD), such as coronary artery disease. Innate immune cells play a crucial role in ASCVD and might also play a pivotal role in the development of CAVD. This review summarizes the current knowledge on the role of innate immune cells, both in the circulation and in the aortic valve, in the development of CAVD and the similarities and differences with ASCVD. Trained immunity and clonal haematopoiesis of indeterminate potential are proposed as novel immunological mechanisms that possibly contribute to the pathophysiology of CAVD and new possible treatment targets are discussed.