Immunogenetics of Atherosclerosis-Link between Lipids, Immunity, and Genes

Capsiate attenuates atherosclerosis by activating Nrf2/GPX4 pathway and reshaping the intestinal microbiota in ApoE-/- mice

Atherosclerosis (AS) is the basis of cardiovascular diseases (CVDs) and remains the major contributor to death worldwide. Capsiate is derived from sweet pepper fruit and exhibits numerous pharmacological activities. The objective of this study was to elucidate the protective role of capsiate in atherosclerosis by examining its effect and the underlying regulatory pathways. Here, we showed that capsiate treatment alleviates atherosclerosis in atherosclerosis-prone apolipoprotein E-deficient (ApoE-/-) mice. We found that capsiate effectively reduced the plaque area and body weight compared to the Model group. Capsiate inhibited inflammatory response by downregulating phosphoinositide 3-kinase/protein kinase B/nuclear factor-κB pathway. Additionally, further investigation indicated that capsiate could regulate lipid levels in mice via reducing the expressions of 3-hydroxy-3-methylglutaryl coenzyme A reductase and low-density lipoprotein receptor, and increasing the expression of recombinant cytochrome P450 7A1. Furthermore, capsiate effectively activated transient receptor potential vanilloid subfamily member 1 in ApoE-/- mice fed a high-fat diet. The microbial sequencing demonstrated capsiate administration significantly regulated the gut microbiota disturbance and increased some beneficial bacterial (Lachnospiraceae NK4A136 group) levels in ApoE-/- mice. Human umbilical vein endothelial cells (HUVECs) were exposed to oxidized low-density lipoprotein (ox-LDL) to stimulate atherosclerotic endothelial damage in vitro. Our study revealed that capsiate inhibited ox-LDL-induced HUVECs injury and inflammation. We further investigated the effects of capsiate on ferroptosis in vivo and in vitro; it was found that capsiate exhibited anti-ferroptosis through regulating nuclear factor erythroid 2-related factor 2/glutathione peroxidase 4 pathway. Interestingly, ML385 reversed the anti-ferroptosis effect of capsiate in HUVECs. Taken together, our findings suggest a promising use of small-molecule drug capsiate for the treatment of AS and related CVDs.

IMPORTANCE

Capsiate has been found to inhibit fat accumulation, promote energy metabolism, and exhibit anti-inflammatory and antioxidative properties. However, there has still been no study on the ferroptosis and gut microbiota of capsiate in atherosclerosis (AS) mouse models. Our study is the first to report on the reshaping of the structure of the gut microbiota by capsiate in AS, and to explore the potential mechanism underlying the improvement of AS. In this study, we demonstrated that capsiate could effectively alleviate high-fat diet-induced AS in apolipoprotein E-deficient mice by inhibiting inflammatory response, improving serum lipid profiles, activating transient receptor potential vanilloid subfamily member 1 pathway, and suppressing ferroptosis. Moreover, the study reported the potential of gut microbiota as mediators of capsiate therapy for AS in animal models. Therefore, these findings may provide robust experimental support for the clinical use of capsiate for AS treatment.

Evaluations of metabolic and innate immunity profiles in subjects with familial hypercholesterolemia with or without subclinical atherosclerosis

BACKGROUND

Familial hypercholesterolemia (FH) is a genetic condition characterized by high low-density lipoprotein cholesterol (LDL-C). The presence of risk modifiers could promote the atherosclerotic injury beyond LDL-C. Our aim was to evaluate metabolic and innate immunity profiles in FH subjects with or without subclinical atherosclerosis.

METHODS

In this cross-sectional observational study, we evaluated 211 genetically confirmed FH subjects on LDL-C target and without cardiovascular diseases. Biochemical analyses, LDL-C burden (LCB) calculation and vascular profile evaluation were obtained from all subjects. Study population was divided into two groups according to subclinical atherosclerosis: the subclinical atherosclerosis (SA) group and non-subclinical atherosclerosis (NSA) group.

RESULTS

SA group had higher LDL-C at diagnosis (288.35 ± 24.52 vs 267.92 ± 23.86, p < 0.05) and LCB (13,465.84 ± 3617.46 vs 10,872.63 ± 3594.7, p < 0.001) than NSA group. SA group had higher white blood cell count (WBCC, 6.9 ± 1.66 vs 6.1 ± 1.16), neutrophil count (NC, 4.2 ± 1.3 vs 3.6 ± 1.11), monocyte count (MC, 0.8 ± 0.2 vs 0.4 ± 0.1), triglyceride to high-density lipoprotein ratio (TG/HDL, 1.73 ± 0.72 vs 1.45 ± 0.69), triglyceride-glucose index (TyG, 8.29 ± 0.35 vs 8.01 ± 0.33) than NSA group (p value for all < 0.01). Multivariate logistic regression analysis showed that LCB (p < 0.01), WBCC (p < 0.01), NC (p < 0.05), MC (p < 0.05) were associated with subclinical atherosclerosis. Simple linear regression analyses showed that LCB was associated with WBCC, NC, MC (p value for all < 0.01).

CONCLUSION

An increased LCB and an impaired innate immunity profile were found in FH subjects with subclinical atherosclerosis and they were independently associated with atherosclerotic injury. LCB could modulate the innate immunity profile.

Genetically predicted HLA-DR+ natural killer cells as potential mediators in the lipid-coronary artery disease/ calcification (CAD/CAC) causal pathway

Background

Coronary artery disease (CAD) imposes a significant global health burden, necessitating a deeper comprehension of its genetic foundations to uncover innovative therapeutic targets. Employing a comprehensive Mendelian randomization (MR) approach, we aimed to explore the genetic associations between lipid profiles, immune cell phenotypes, and CAD risk.

Methods

Utilizing data from recent large-scale genome-wide association studies (GWAS), we scrutinized 179 lipid and 731 immune cell phenotypes to delineate their genetic contributions to CAD pathogenesis, including coronary artery calcification (CAC). Moreover, specific immune cell phenotypes were examined as potential mediators of the lipid-CAD/CAC causal pathway.

Results

Among the 162 lipid species with qualified instrumental variables (IVs) included in the analysis, we identified 36 lipids that exhibit a genetic causal relationship with CAD, with 29 being risk factors and 7 serving as protective factors. Phosphatidylethanolamine (18:0_20:4) with 8 IVs (OR, 95% CI, P-value: 1.04, 1.02-1.06, 1.50E-04) met the Bonferroni-corrected significance threshold (0.05/162 = 3.09E-04). Notably, all 18 shared lipids were determined to be risk factors for both CAD and CAC, including 16 triacylglycerol traits (15 of which had ≥ 3 IVs), with (50:1) exhibiting the highest risk [OR (95% CI) in CAC: 1.428 (1.129-1.807); OR (95% CI) in CAD: 1.119 (1.046-1.198)], and 2 diacylglycerol traits. Furthermore, we identified HLA DR+ natural killer cells (IVs = 3) as nominally significant with lipids and as potential mediators in the causal pathway between diacylglycerol (16:1_18:1) or various triacylglycerols and CAD (mediated effect: 0.007 to 0.013).

Conclusions

This study provides preliminary insights into the genetic correlations between lipid metabolism, immune cell dynamics, and CAD susceptibility, highlighting the potential involvement of natural killer cells in the lipid-CAD/CAC causal pathway and suggesting new targets for therapy. Further evidence is necessary to substantiate our findings.

Exploring global research trends in Chinese medicine for atherosclerosis: a bibliometric study 2012-2023

Background

While Traditional Chinese Medicine (TCM) boasts an extensive historical lineage and abundant clinical expertise in addressing atherosclerosis, this field is yet to be penetrated adequately by bibliometric studies. This study is envisaged to evaluate the contemporary scenario of TCM in conjunction with atherosclerosis over the preceding decade while also identifying forthcoming research trends and emerging topics via the lens of bibliometric analysis.

Methods

Literature pertaining to TCM and atherosclerosis, circulated between January 1, 2012 and November 14, 2023, was garnered for the purpose of this research. The examination embraced annual publications, primary countries/regions, engaged institutions and authors, scholarly journals, references, and keywords, utilizing analytical tools like Bibliometrix, CiteSpace, ScimagoGraphica, and VOSviewer present in the R package.

Result

This field boasts a total of 1,623 scholarly articles, the majority of which have been contributed by China in this field, with significant contributions stemming from the China Academy of Traditional Chinese Medicine and the Beijing University of Traditional Chinese Medicine. Moreover, this field has received financial support from both the National Natural Science Foundation of China and the National Key Basic Research Development Program. Wang Yong tops the list in terms of publication count, while Xu Hao's articles take the lead for the total number of citations, positioning them at the core of the authors' collaborative network. The Journal of Ethnopharmacology leads with the most publications and boasts the greatest total number of citations. Principal research foci within the intersection of Chinese Medicine and Atherosclerosis encompass disease characteristics and pathogenic mechanisms, theoretical underpinnings and syndrome-specific treatments in Chinese medicine, potentialities of herbal interventions, and modulation exerted by Chinese medicines on gut microbiota.

Conclusion

This analysis offers a sweeping survey of the contemporary condition, principal foci, and progressive trends in worldwide research related to Traditional Chinese Medicine (TCM) and atherosclerosis. It further delves into an in-depth dissection of prominent countries, research institutions, and scholars that have made noteworthy strides in this discipline. Additionally, the report analyzes the most cited articles, research developments, and hotspots in the field, providing a reference for future research directions for clinical researchers and practitioners.

Gualou-Xiebai herb pair ameliorate atherosclerosis in HFD-induced ApoE-/- mice and inhibit the ox-LDL-induced injury of HUVECs by regulating the Nrf2-mediated ferroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Atherosclerosis (AS) is a chronic vascular ailment characterized by inflammatory and lipid deposition in the arterial wall caused by endothelial injury. Ferroptosis is a novel type of cell death, and endothelial ferroptosis is a significant contributor to the progression of AS. Gualou-Xiebai (GLXB) is a renowned Chinese herb pair that serves a crucial function in treating AS. However, whether the underlying mechanism of GLXB plays a role in anti-atherosclerotic effects by inhibiting ferroptosis in endothelial cells has not been determined.

AIM OF THE STUDY

To explore the influence of GLXB on endothelial ferroptosis and determine its underlying mechanism of action in AS.

MATERIALS AND METHODS

In ApoE-/- mice, ultrasound was performed in mice fed a high-fat diet (HFD) for 12 weeks to assess the success of AS establishment. Then, ApoE-/- mice were treated with GLXB and Simvastatin (positive control) for 4 weeks. The effects of GLXB on AS pathology were assessed through aorta imaging and hematoxylin-eosin (HE) staining. To confirm the presence of ferroptosis, mitochondrial damage was observed using transmission electron microscope (TEM), along with analysis of free iron and lipid peroxidation levels. In vitro: ox-LDL-induced human vascular endothelial cells (HUVECs) injury and treated with GLXB, the ferroptosis inducer Erastin and an Nrf2 inhibitor ML385. Cell viability was evaluated using the CCK-8 assay in all groups. Flow cytometry was employed to detect lipid peroxidation and intracellular ferrous iron levels. Immunofluorescence staining microscopy verified Nrf2 nuclear translocation. Protein expression were measured by Western blot analysis.

RESULTS

GLXB improved atherosclerotic aortic lesions and vascular plaques. GLXB inhibited endothelial injury in the aorta by decreasing the levels of inflammatory factors and adhesion factors, and by decreasing the shedding of endothelial cells. GLXB suppressed ferroptosis in ApoE-/- mice by attenuating mitochondrial damage in ECs, increasing the levels of glutathione (GSH) and superoxide dismutase (SOD) in aortic tissues and down-regulating the levels of levels of lipid peroxide (LPO) and malondialdehyde (MDA). Interestingly, Erastin was used to demonstrate in vitro that GLXB inhibition of ferroptosis attenuated ox-LDL-induced injuring effects on HUVECs that were reversed by Erastin. Mechanistically, GLXB activates the Nrf2 signaling pathway to inhibit ferroptosis by increasing downstream anti-ferroptosis target proteins and promoting the interaction between Nrf2 and SLC7A11. More convincingly, ML385 (Nrf2 inhibitor) reversed the anti-ferroptosis effect of GLXB.

CONCLUSION

GLXB inhibits ferroptosis-mediated endothelial cell injury via activating the Nrf2 signaling pathway and further alleviates AS pathological damage.

Oil mistparticulate matter exposure induces hyperlipidemia-related inflammation via microbiota/ SCFAs/GPR43 axis inhibition and TLR4/NF-κB activation

Metabolites produced by the human gut microbiota play an important role in fighting and intervening in inflammatory diseases. It remains unknown whether immune homeostasis is influenced by increasing concentrations of air pollutants such as oil mist particulate matters (OMPM). Herein, we report that OMPM exposure induces a hyperlipidemia-related phenotype through microbiota dysregulation-mediated downregulation of the anti-inflammatory short-chain fatty acid (SCFA)-GPR43 axis and activation of the inflammatory pathway. A rat model showed that exposure to OMPM promoted visceral and serum lipid accumulation and inflammatory cytokine upregulation. Furthermore, our research indicated a reduction in both the "healthy" microbiome and the production of SCFAs in the intestinal contents following exposure to OMPM. The SCFA receptor GPR43 was downregulated in both the ileum and white adipose tissues (WATs). The OMPM treatment mechanism was as follows: the gut barrier was compromised, leading to increased levels of lipopolysaccharide (LPS). This increase activated the Toll-like receptor 4 Nuclear Factor-κB (TLR4-NF-κB) signaling pathway in WATs, consequently fueling hyperlipidemia-related inflammation through a positive-feedback circuit. Our findings thus imply that OMPM pollution leads to hyperlipemia-related inflammation through impairing the microbiota-SCFAs-GPR43 pathway and activating the LSP-induced TLR4-NF-κB cascade; our findings also suggest that OMPM pollution is a potential threat to humanmicrobiota dysregulation and the occurrence of inflammatory diseases.

Analysis of polymorphism of innate immunity receptor genes in patients with coronary atherosclerosis and in a population sample from Novosibirsk

Understanding the molecular mechanisms of atherosclerotic vascular lesions formation is necessary both for assessing the risks of cardiovascular diseases and for finding approaches to their therapy. The task remains relevant, despite the large number of studies carried out, because there are differences in the factors of genetic predisposition to atherosclerosis and its complications between different ethno-territorial groups. The aim of this study was to search for genetic variants of pattern recognition receptors associated with lipid metabolism disorders that can lead to the development of coronary atherosclerosis (CA).Material and methods. Analysis of exons and adjacent splicing sites of pattern recognition receptors genes in patients with CA (30 men), and then genotyping of a population sample from Novosibirsk (n = 1441) by real-time PCR for selected rs113706342 of the TLR1 gene and analysis of associations of its carriage with lipid metabolism were performed.Results and discussion. The frequency of the minor allele rs113706342 C of the TLR1 gene in the sample of residents of Novosibirsk was 0.0114 ± 0.0062, the carriage of this variant was associated with an increased level of low-density lipoprotein cholesterol in both women and men (p = 0.009 and p = 0.019, respectively). Women carriers of the minor allele C for rs113706342 also had a statistically significant increase in total serum cholesterol (p = 0.013) compared with TT homozygotes. To test the role of this variant in the development of CA, genotyping of an extended sample of patients is required. In one of the patients with CA, a previously undescribed single nucleotide variant chr16:3614637 G/C was found, leading to the Leu101Val substitution in the NLRC3 gene; segregation analysis is required to assess its functional significance.Conclusions. The association of rs113706342 C of the TLR1 gene with lipid metabolism disorders in the Russian population is shown.

Periodontitis exacerbates atherosclerosis through Fusobacterium nucleatum-promoted hepatic glycolysis and lipogenesis

AIMS

Positive associations between periodontitis (PD) and atherosclerosis have been established, but the causality and mechanisms are not clear. We aimed to explore the causal roles of PD in atherosclerosis and dissect the underlying mechanisms.

METHODS AND RESULTS

A mouse model of PD was established by ligation of molars in combination with application of subgingival plaques collected from PD patients and then combined with atherosclerosis model induced by treating atheroprone mice with a high-cholesterol diet (HCD). PD significantly aggravated atherosclerosis in HCD-fed atheroprone mice, including increased en face plaque areas in whole aortas and lesion size at aortic roots. PD also increased circulating levels of triglycerides and cholesterol, hepatic levels of cholesterol, and hepatic expression of rate-limiting enzymes for lipogenesis. Using 16S ribosomal RNA (rRNA) gene sequencing, Fusobacterium nucleatum was identified as the most enriched PD-associated pathobiont that is present in both the oral cavity and livers. Co-culture experiments demonstrated that F. nucleatum directly stimulated lipid biosynthesis in primary mouse hepatocytes. Moreover, oral inoculation of F. nucleatum markedly elevated plasma levels of triglycerides and cholesterol and promoted atherogenesis in HCD-fed ApoE-/- mice. Results of RNA-seq and Seahorse assay indicated that F. nucleatum activated glycolysis, inhibition of which by 2-deoxyglucose in turn suppressed F. nucleatum-induced lipogenesis in hepatocytes. Finally, interrogation of the molecular mechanisms revealed that F. nucleatum-induced glycolysis and lipogenesis by activating PI3K/Akt/mTOR signalling pathway in hepatocytes.

CONCLUSIONS

PD exacerbates atherosclerosis and impairs lipid metabolism in mice, which may be mediated by F. nucleatum-promoted glycolysis and lipogenesis through PI3K/Akt/mTOR signalling in hepatocytes. Treatment of PD and specific targeting of F. nucleatum are promising strategies to improve therapeutic effectiveness of hyperlipidaemia and atherosclerosis.

Atherosclerosis and Inflammation: Insights from the Theory of General Pathological Processes

Recent advances have greatly improved our understanding of the molecular mechanisms behind atherosclerosis pathogenesis. However, there is still a need to systematize this data from a general pathology perspective, particularly with regard to atherogenesis patterns in the context of both canonical and non-classical inflammation types. In this review, we analyze various typical phenomena and outcomes of cellular pro-inflammatory stress in atherosclerosis, as well as the role of endothelial dysfunction in local and systemic manifestations of low-grade inflammation. We also present the features of immune mechanisms in the development of productive inflammation in stable and unstable plaques, along with their similarities and differences compared to canonical inflammation. There are numerous factors that act as inducers of the inflammatory process in atherosclerosis, including vascular endothelium aging, metabolic dysfunctions, autoimmune, and in some cases, infectious damage factors. Life-critical complications of atherosclerosis, such as cardiogenic shock and severe strokes, are associated with the development of acute systemic hyperinflammation. Additionally, critical atherosclerotic ischemia of the lower extremities induces paracoagulation and the development of chronic systemic inflammation. Conversely, sepsis, other critical conditions, and severe systemic chronic diseases contribute to atherogenesis. In summary, atherosclerosis can be characterized as an independent form of inflammation, sharing similarities but also having fundamental differences from low-grade inflammation and various variants of canonical inflammation (classic vasculitis).

A circular RNA, circUSP36, accelerates endothelial cell dysfunction in atherosclerosis by adsorbing miR-637 to enhance WNT4 expression

Atherosclerosis is a fatal disorder that is fundamental to various cardiovascular diseases and severely threatens people’s health worldwide. Several studies have demonstrated the role of circular RNAs (circRNAs) in the pathogenesis of atherosclerosis. circUSP36 acts as a key modulator in the progression of atherosclerosis, but the molecular mechanism underlying this role is as yet unclear. This study aimed to elucidate the mechanism by which circUSP36 exerts its function in an in vitro cell model of endothelial cell dysfunction, which is one of pathological features of atherosclerosis. The circRNA traits of circUSP36 were confirmed, and we observed high expression of circUSP36 in endothelial cells exposed to oxidized low-density lipoprotein (ox-LDL). Functional assays revealed that overexpression of circUSP36 suppressed proliferation and migration of ox-LDL-treated endothelial cells. In terms of its mechanism, circUSP36 adsorbed miR-637 by acting as an miRNA sponge. Moreover, enhanced expression of miR-637 abated the impact of circUSP36 on ox-LDL-treated endothelial cell dysregulation. Subsequently, the targeting relationship between miR-637 and WNT4 was predicted using bioinformatics tools and was confirmed via luciferase reporter and RNA pull-down assays. Notably, depletion of WNT4 rescued circUSP36-mediated inhibition of endothelial cell proliferation and migration. In conclusion, circUSP36 regulated WNT4 to aggravate endothelial cell injury caused by ox-LDL by competitively binding to miR-637; this finding indicates circUSP36 to be a promising biomarker for the diagnosis and therapy of atherosclerosis.