Netrin-1 in Atherosclerosis: Relationship between Human Macrophage Intracellular Levels and In Vivo Plaque Morphology

Insights from the neural guidance factor Netrin-1 into neurodegeneration and other diseases

Netrin-1 was initially discovered as a neuronal growth cue for axonal guidance, and its functions have later been identified in inflammation, tumorigenesis, neurodegeneration, and other disorders. We have recently found its alterations in the brains with Alzheimer's disease, which might provide important clues to the mechanisms of some unique pathologies. To provide better understanding of this promising molecule, we here summarize research progresses in genetics, pathology, biochemistry, cell biology and other studies of Netrin-1 about its mechanistic roles and biomarker potentials with an emphasis on clinical neurodegenerative disorders in order to expand understanding of this promising molecular player in human diseases.

GCN-GENE: A novel method for prediction of coronary heart disease-related genes

Coronary heart disease is the most common heart disease, it can induce myocardial infarction, and the cause of the disease has a lot to do with life and eating habits. The results of a large number of epidemiological studies at home and abroad show that the incidence of coronary heart disease has an obvious familial tendency. However, little is known about the genetic factors of coronary heart disease. Although genome-wide association analysis and gene knockout experiments have found some genes related to coronary heart disease, there are still a large number of genes potentially related to coronary heart disease that have not been discovered. If it is confirmed by biological experimental means, the time and money cost is too high. Therefore, it is urgent to identify genes related to coronary heart disease on a large scale by computational means, so as to conduct targeted biological experimental verification. This paper proposes a deep learning method based on biological networks for the identification of coronary heart disease-related genes. We constructed gene interaction networks and extracted gene expression levels in different tissues as features. Through the association information and expression characteristics between genes, we constructed a model of coronary heart disease-related genes. Through cross-validation, we found that our proposed GCN-GENE that has AUC as 0.75 and AUPR as 0.78, which is more accurate than other methods and is a reliable method for predicting coronary heart disease-related genes.

Association between serum netrin-1, netrin-4 and risk of the acute coronary syndrome in patients with type 2 diabetes mellitus-A pilot study

The present study was done to assess the diagnostic utility of serum netrin-1 and netrin-4 for recognising the acute coronary syndrome (ACS) in type 2 diabetes mellitus (T2DM) patients. Forty-two T2DM patients with ACS (Cases) and forty-two T2DM patients without ACS (Controls) were compared. Cases had lower serum netrin-1 and netrin-4 levels than controls and were negatively associated with creatinine kinase-total, creatinine kinase-MB, troponin-T and H-FABP. ROC analysis showed that netrin-1 and netrin-4 had good sensitivity and specificity for ACS prediction in T2DM patients. Serum netrin-1 and netrin-4 levels might be considered complementary markers for ACS diagnosis in T2DM patients.

Common Polymorphisms in the RGMa Promoter Are Associated With Cerebrovascular Atherosclerosis Burden in Chinese Han Patients With Acute Ischemic Cerebrovascular Accident

Repulsive guidance molecule a (RGMa) plays a vital role in the progression of numerous inflammatory diseases. However, whether it participates in atherosclerosis development is not known. Here, we explored the influence of RGMa in atherogenesis by investigating whether an association exists between functional polymorphisms in the RGMa promoter and cerebrovascular atherosclerosis burden (CAB) in Chinese Han patients diagnosed with acute ischemic cerebrovascular accident. To this end, we conducted a genetic association study on 201 patients with prior diagnoses of acute ischemic stroke or transient ischemic attack recruited from our hospital. After admission, we conducted three targeted single-nucleotide polymorphisms (SNPs) genotyping and evaluated CAB by computed tomography angiography. We used logistic regression modeling to analyze genetic associations. Functional polymorphism analysis indicated an independent association between the rs725458 T allele and increased CAB in patients with acute ischemic cerebrovascular accident [adjusted odds ratio (OR) = 1.66, 95% confidence interval (CI) = 1.01–2.74, P = 0.046]. In contrast, an association between the rs4778099 AA genotype and decreased CAB (adjusted OR = 0.10, 95% CI = 0.01–0.77, P = 0.027) was found. Our Gene Expression Omnibus analysis revealed lower RGMa levels in the atherosclerotic aortas and in the macrophages isolated from plaques than that in the normal aortas and macrophages from normal tissue, respectively. In conclusion, the relationship between RGMa and cerebrovascular atherosclerosis suggests that RGMa has a potential vasoprotective effect. The two identified functional SNPs (rs725458 and rs4778099) we identified in the RGMa promoter are associated with CAB in patients diagnosed with acute ischemic cerebrovascular accident. These findings offer a promising research direction for RGMa-related translational studies on atherosclerosis.

Silencing Myeloid Netrin-1 Induces Inflammation Resolution and Plaque Regression

Rationale: Therapeutic efforts to decrease atherosclerotic cardiovascular disease risk have focused largely on reducing atherogenic lipoproteins, yet lipid-lowering therapies alone are insufficient to fully regress plaque burden. We postulate that arterial repair requires resolution of a maladaptive immune response and that targeting factors that hinder inflammation resolution will facilitate plaque regression. Objective: The guidance molecule Ntn1 (netrin-1) is secreted by macrophages in atherosclerotic plaques, where it sustains inflammation by enhancing macrophage survival and blocking macrophage emigration. We tested whether silencing Ntn1 in advanced atherosclerosis could resolve arterial inflammation and regress plaques. Methods and Results: To temporally silence Ntn1 in myeloid cells, we generated genetically modified mice in which Ntn1 could be selectively deleted in monocytes and macrophages using a tamoxifen-induced CX3CR1-driven cre recombinase (Ntn1fl/flCx3cr1creERT2+) and littermate control mice (Ntn1fl/flCx3cr1WT). Mice were fed Western diet in the setting of hepatic PCSK9 (proprotein convertase subtilisin/kexin type 9) overexpression to render them atherosclerotic and then treated with tamoxifen to initiate deletion of myeloid Ntn1 (MøΔNtn1) or not in controls (MøWT). Morphometric analyses performed 4 weeks later showed that myeloid Ntn1 silencing reduced plaque burden in the aorta (−50%) and plaque complexity in the aortic root. Monocyte-macrophage tracing experiments revealed lower monocyte recruitment, macrophage retention, and proliferation in MøΔNtn1 compared with MøWT plaques, indicating a restructuring of monocyte-macrophage dynamics in the artery wall upon Ntn1 silencing. Single-cell RNA sequencing of aortic immune cells before and after Ntn1 silencing revealed upregulation of gene pathways involved in macrophage phagocytosis and migration, including the Ccr7 chemokine receptor signaling pathway required for macrophage emigration from plaques and atherosclerosis regression. Additionally, plaques from MøΔNtn1 mice showed hallmarks of inflammation resolution, including higher levels of proresolving macrophages, IL (interleukin)-10, and efferocytosis, as compared to plaques from MøWT mice. Conclusion: Our data show that targeting Ntn1 in advanced atherosclerosis ameliorates atherosclerotic inflammation and promotes plaque regression.

Macrophages in Health and Non-Infectious Disease

In this Special Issue of Biomedicines, we have many insightful reviews and research papers on the subject "Macrophages in Health and Non-infectious Disease", but first; we should discuss briefly the current situation in the field [...].