CD226 gene polymorphism (rs763361 C>T) is associated with susceptibility to type 1 diabetes mellitus among Egyptian children

CD226 knockout alleviates high-fat diet induced obesity by suppressing proinflammatory macrophage phenotype

Obesity is associated with chronic low-grade inflammation, contributing to an increasing prevalence of chronic metabolic diseases, such as insulin resistance, non-alcoholic fatty liver disease (NALFD), and steatohepatitis. Macrophages are the predominant immune cells in adipose tissues. Adipose tissue macrophages (ATMs) would switch to pro-inflammatory M1 state during obesity, causing local and systemic inflammation. However, the regulatory mechanism of ATMs has not yet been well described within this process. Using a high-fat diet (HFD)–induced mouse obesity model, we found that the costimulatory molecule CD226 was highly expressed on ATMs and knockout (KO) of CD226 alleviated obesity caused by HFD. Loss of CD226 reduced the accumulation of ATMs and hindered macrophage M1 polarization, with lower serum proinflammatory cytokine levels. Furthermore, deficiency of CD226 on ATMs decreased the phosphorylation levels of VAV1, AKT, and FOXO1 and thereby upregulated PPAR-γ. Further administration of PPAR-γ inhibitor restored M1 phenotype in CD226KO ATMs. In summary, loss of CD226 alleviates the HFD-induced obesity and systemic inflammation through inhibition of the accumulation and M1 polarization of ATMs in which PPAR-γ-dependent signaling pathway is involved, suggesting that CD226 may be identified as a potential molecular target for the clinical treatment of obesity.

Diabetes and Genetics: A Relationship Between Genetic Risk Alleles, Clinical Phenotypes and Therapeutic Approaches

Unveiling human genome through successful completion of Human Genome Project and International HapMap Projects with the advent of state of art technologies has shed light on diseases associated genetic determinants. Identification of mutational landscapes such as copy number variation, single nucleotide polymorphisms or variants in different genes and loci have revealed not only genetic risk factors responsible for diseases but also region(s) playing protective roles. Diabetes is a global health concern with two major types - type 1 diabetes (T1D) and type 2 diabetes (T2D). Great progress in understanding the underlying genetic predisposition to T1D and T2D have been made by candidate gene studies, genetic linkage studies, genome wide association studies with substantial number of samples. Genetic information has importance in predicting clinical outcomes. In this review, we focus on recent advancement regarding candidate gene(s) associated with these two traits along with their clinical parameters as well as therapeutic approaches perceived. Understanding genetic architecture of these disease traits relating clinical phenotypes would certainly facilitate population stratification in diagnosing and treating T1D/T2D considering the doses and toxicity of specific drugs.

Imbalance of the CD226/TIGIT Immune Checkpoint Is Involved in the Pathogenesis of Primary Biliary Cholangitis

The relationship between the cluster of differentiation 226 (CD226)/T cell Ig and ITIM domain (TIGIT) immune checkpoint and primary biliary cholangitis (PBC) pathogenesis is unknown. Herein, PBC patients (n = 42) showed significantly higher proportions of peripheral CD8⁺ T and CD4⁺ T cells expressing either CD226 or TIGIT than disease (n = 25) and healthy (n = 30) controls. The percentage of CD8⁺TIGIT⁺ T cell was negatively associated with total bilirubin, direct bilirubin, total bile acid, γ-glutamyl transpeptidase, and alkaline phosphatase, but positively correlated with platelet count; alkaline phosphatase was positively associated with the frequency of CD8⁺CD226⁺ T cell; and the CD226/TIGIT ratio of CD8⁺ T cell was positively associated with total bilirubin, direct bilirubin, total bile acid, γ-glutamyl transpeptidase, alkaline phosphatase, and aspartate aminotransferase to platelet ratio, but negatively correlated with albumin and platelet count. The effector function of CD8⁺CD226⁺ T cells was more robust than the CD8⁺CD226^- counterparts. CD226 blockade reduced CD107a⁺, IFN-γ⁺, and TNF-α⁺ proportions among CD8⁺CD226⁺ T cells, inhibiting CD8⁺ T cell proliferation. In conclusion, CD226/TIGIT immune checkpoint imbalance is involved in the pathogenesis of PBC. The CD226/TIGIT ratio of CD8⁺ T cell is a potential biomarker for evaluating the disease status and the prognosis of PBC patients. Moreover, CD8⁺CD226⁺ T cells represent a possible therapeutic target for PBC, and blocking CD226 could inhibit the activity of this cell subset in vitro.

Role of CD226 Rs763361 Polymorphism in Susceptibility to Multiple Autoimmune Diseases

Background: Gly307Ser (rs763361) polymorphism in Cluster of Differentiation 226 (CD226) gene has been implicated in susceptibility to autoimmune diseases (ADs) with controversial results. This study aimed to conduct a meta-analysis for examining the relationship between CD226 rs763361 polymorphism and ADs risk. Methods: a literature search was performed to identify relevant studies published in Embase, PubMed, Wanfang, and China National Knowledge Infrastructure. In the most appropriate genetic models, pooled odds ratio (OR) with 95% confidence interval (CI) was calculated for evaluating the strength of the associations. Besides standard meta-analysis, cumulative meta-analysis was also conducted to assess the trend in OR over time. Also, we performed subgroup and sensitivity analysis, and checked for the heterogeneity and publication bias. Results: Twenty-nine reports with 51 independent studies, comprising 18157 cases and 29904 controls, were enrolled in this meta-analysis. Among overall and various ethnic populations (Europeans, Asians, Africans, and South Americans), CD226 rs763361 polymorphism was significantly associated with ADs susceptibility; in the subgroup analysis by disease type, rs763361 polymorphism revealed significant associations with the risk of RA, SLE, T1D, and MS. The sensitivity analysis and cumulative meta-analysis confirmed the stability and robustness of these significant results. However, no evidence of stable significant association emerged in the subgroup analysis of SSc. Conclusion: These findings demonstrate that CD226 rs763361 polymorphism confers susceptibility to ADs in the overall population, Europeans, Asians, Africans, and South Americans. rs763361 polymorphism in CD226 gene may be a potential susceptible predictor of ADs especially RA, SLE, T1D, and MS.