Thymic stromal lymphopoietin induces platelet mitophagy and promotes thrombosis in Kawasaki disease

Platelets in Kawasaki disease: mediators of vascular inflammation

Kawasaki disease, a systemic vasculitis that affects young children and can result in coronary artery aneurysms, is the leading cause of acquired heart disease among children. A hallmark of Kawasaki disease is increased blood platelet counts and platelet activation, which is associated with an increased risk of developing resistance to intravenous immunoglobulin and coronary artery aneurysms. Platelets and their releasate, including granules, microparticles, microRNAs and transcription factors, can influence innate immunity, enhance inflammation and contribute to vascular remodelling. Growing evidence indicates that platelets also interact with immune and non-immune cells to regulate inflammation. Platelets boost NLRP3 inflammasome activation and IL-1β production by human immune cells by releasing soluble mediators. Activated platelets form aggregates with leukocytes, such as monocytes and neutrophils, enhancing numerous functions of these cells and promoting thrombosis and inflammation. Leukocyte-platelet aggregates are increased in children with Kawasaki disease during the acute phase of the disease and can be used as biomarkers for disease severity. Here we review the role of platelets in Kawasaki disease and discuss progress in understanding the immune-effector role of platelets in amplifying inflammation related to Kawasaki disease vasculitis and therapeutic strategies targeting platelets or platelet-derived molecules.

The crosstalk between mitochondrial quality control and metal-dependent cell death

Mitochondria are the centers of energy and material metabolism, and they also serve as the storage and dispatch hubs of metal ions. Damage to mitochondrial structure and function can cause abnormal levels and distribution of metal ions, leading to cell dysfunction and even death. For a long time, mitochondrial quality control pathways such as mitochondrial dynamics and mitophagy have been considered to inhibit metal-induced cell death. However, with the discovery of new metal-dependent cell death including ferroptosis and cuproptosis, increasing evidence shows that there is a complex relationship between mitochondrial quality control and metal-dependent cell death. This article reviews the latest research results and mechanisms of crosstalk between mitochondrial quality control and metal-dependent cell death in recent years, as well as their involvement in neurodegenerative diseases, tumors and other diseases, in order to provide new ideas for the research and treatment of related diseases.

Silencing of FUN14 Domain Containing 1 Inhibits Platelet Activation in Diabetes Mellitus through Blocking Mitophagy

Platelet hyperactivity represents a deleterious physiological phenomenon in diabetes mellitus (DM). This study aimed to explore the role of FUN14 domain containing 1 (FUNDC1) in platelet activation within the context of DM and to uncover relevant mechanisms, with a focus on mitophagy. A mouse model of DM was established by high-fat feeding and streptozotocin injection. Platelets isolated from whole blood were exposed to carbonyl cyanide-4-(trifluo-romethoxy)phenylhydrazone (FCCP) to induce mitophagy. The relative mRNA expression of FUNDC1 was detected by quantitative real-time PCR (qRT-PCR). Western blotting was employed to measure the protein levels of FUNDC1, the ratio of LC3-II toLC3-I, and cleaved caspase-3. Immunofluorescence and flow cytometry were performed to assess LC3-positive mitochondria and platelet activation factor CD62P, respectively. Additionally, serum levels of β-thrombo-globulin (β-TG) and platelet factor 4 (PF4)were measured by enzyme-linked immunosorbent assay. FUNDC1 expression was elevated in DM mice, and its silencing decreased the body weight and fasting blood glucose. Inhibition of FUNDC1 also significantly attenuated FCCP-induced platelet mitophagy, as evidenced by the down-regulation of the LC3-II/LC3-I ratio, up-regulation of Tomm20, and diminished presence of LC3-positive mitochondria. Moreover, platelet activation was noted in DM mice; this activation was mitigated upon FUNDC1 silencing, which was confirmed by the down-regulation of cleaved caspase-3 and CD62P as well as reductions in β-TG and PF4 serum levels. Silencing of FUNDC1 inhibited platelet hyperactivity in DM by impeding mitophagy. As such, FUNDC1-midiated mitophagy may be a promising target for the treatment of DM and its associated cardiovascular complications related cardiovascular events.

Whole-Exome Sequencing for Identification of Potential Sex-Biased Variants in Kawasaki Disease Patients

Kawasaki disease (KD) is an autoimmune disease of unknown etiology and has become a main cause of childhood acquired heart disease. KD is more prevalent in males than in females. The reason for this sex bias is unknown. Here, we used whole-exome sequencing (WES) to identify significantly different variants between male and female KD patients. From WES result, a total of 19,500 shared genetic variants in 8421 genes were captured via a series of filters. Further comparisons based on sex were performed to obtain 34 potential sex-biased variants in 34 genes for GO and Reactome Gene Sets enrichment analyses. Moreover, we selected 6 variants associated with immune, cells adhesion, platelet function, homeostasis, and ion channel signaling and expanded the sample size (1247 KD patients containing 713 males and 534 females, 803 healthy population containing 481 males and 322 females) for genotyping validation. From the results, USH2A/rs148135241, LMO7/rs142687160, CEMIP/rs12441101, and EFCC1/rs142391828 presented significant differences of alleles/genotypes frequency distributions between male and female only in KD patients (which were consistent with the result of WES analysis) but not in healthy population. In addition, the result also found that only EFCC1/rs142391828 polymorphism was associated with KD susceptibility. This result suggested that those four variants might play critical roles in sex bias in KD. The study would be in favor of a sex-specific genome atlas establishing and novel sex-specific precision therapies development for KD.

Platelet activation and mitophagy induction by thymic stromal lymphopoietin (TSLP) is associated with thrombosis in Kawasaki disease

Kawasaki disease (KD) is an acute vasculitis of early childhood with unknown cause, which can be complicated by coronary artery lesions resulting in thrombosis. Fu and coworkers identify thymic stromal lymphopoietin (TSLP) to be increased in KD patients with thrombosis. They demonstrate that TSLP can activate platelets, induce mitophagy and trigger thrombus formation in vitro, suggesting that TSLP may have potential as a therapeutic target against KD-associated thrombosis. Commentary on: Fu L, et al. TSLP induces platelet mitophagy and promotes thrombosis in Kawasaki disease. Br J Haematol. 2023; 200:776-791.