Superagonistic CD28 Protects against Renal Ischemic Injury by Expansion of Regulatory T-Cell

Elucidating the Causal Link Between Treg-Related Immune Traits and Atherosclerosis-Related Cardiovascular Diseases: A Bidirectional Mendelian Randomisation Analysis

AIM

Regulatory T cells (Tregs) play a crucial role in the development and progression of atherosclerosis. However, the specific association between Treg immune traits and atherosclerosis and related cardiovascular diseases remains unclear, impeding their potential for clinical therapeutic application.

METHOD

Fifty-eight Treg-related immune traits were obtained from the latest summary level genome-wide association study, which included 3,757 individuals from Sardinia. Additionally, three atherosclerosis subsets and three atherosclerosis-related cardiovascular diseases were obtained from the FinnGen database. Subsequently, comprehensive bidirectional Mendelian randomisation (MR) analysis was performed using inverse-variance weighting as the primary method. Sensitivity analyses were performed to verify the robustness, heterogeneity, and horizontal pleiotropy of the results. Co-localisation analysis was performed to detect whether the exposure and outcome shared causal variants.

RESULTS

Four significant Treg-related immune traits linked to a lower risk of three cardiovascular diseases were identified in the forward MR analysis. Specifically, two traits were identified for cerebral atherosclerosis: CD39+ activated CD4+ Treg absolute count (OR 0.70, 95% CI 0.57-0.87, pFDR=0.040 [false discovery rate]) and activated CD4 Tregs % CD4+ T cells (OR 0.64, 95% CI 0.48-0.84, pFDR=0.040). In addition, CD28 on secreting CD4 Tregs (OR 0.95, 95% CI 0.93-0.98, pFDR=0.014) was detected for other atherosclerosis. In ischaemic heart disease, CD28 on activated CD4 Tregs was protective (OR 0.96, 95% CI 0.95-0.98, pFDR=0.020). An increased intensity of CD3 and CD4 was observed in reverse MR after the occurrence of stroke and ischaemic heart disease, respectively, whereas a lower number and proportion of CD39+-secreting CD4 Tregs were noted after ischaemic heart disease. Co-localisation analysis indicated that there were no shared causal variants among significant associations in forward MR.

CONCLUSION

This study revealed a potential causal relationship between Tregs and atherosclerosis and related cardiovascular diseases, providing a plausible hypothesis for future clinical and basic research.

Ischemia Reperfusion Injury: Opportunities for Nanoparticles

Ischemia reperfusion (IR)-induced oxidative stress, accompanied by inflammatory responses, contributes to morbidity and mortality in numerous diseases such as acute coronary syndrome, stroke, organ transplantation, and limb injury. Ischemia results in profound hypoxia and tissue dysfunction, whereas subsequent reperfusion further aggravates ischemic tissue damage through inducing cell death and activating inflammatory responses. In this review, we highlight recent studies of therapeutic strategies against IR injury. Furthermore, nanotechnology offers significant improvements in this area. Hence, we also review recent advances in nanomedicines for IR therapy, suggesting them as potent and promising strategies to improve drug delivery to IR-injured tissues and achieve protective effects.

Renal regeneration after acute kidney injury

Acute kidney injury is common and associated with negative renal and patient outcomes. The human kidney has a real but limited regeneration capacity. Understanding renal regeneration may allow us to manipulate this process and thus develop therapeutic weapons to improve patients' outcome. In the first part of this paper we discuss the clinical factors associated with renal recovery: baseline patient particularities, acute kidney injury characteristics and the medical approach taken in the short and long-term. In the second part, the cellular and molecular mechanisms underlying renal regeneration are explored. The immune system seems to have an important role, first promoting inflammation and then tissue healing. Other players, such as cellular senescence, mitochondrial dysfunction, renal haemodynamics and metabolic reprogramming also have a role in renal regeneration. We aim to develop a short review of renal regeneration, offering a holistic view of this process.

Regulatory T cells in acute and chronic kidney diseases

Foxp3-expressing CD4+ regulatory T cells (Tregs) make up one subset of the helper T cells (Th) and are one of the major mechanisms of peripheral tolerance. Tregs prevent abnormal activation of the immune system throughout the lifespan, thus protecting from autoimmune and inflammatory diseases. Recent studies have elucidated the role of Tregs beyond autoimmunity. Tregs play important functions in controlling not only innate and adaptive immune cell activation, but also regulate nonimmune cell function during insults and injury. Inflammation contributes to a multitude of acute and chronic diseases affecting the kidneys. This review examines the role of Tregs in pathogenesis of renal inflammatory diseases and explores the approaches for enhancing Tregs for prevention and therapy of renal inflammation.