Integration of transcriptomics and metabolomics reveals pathways involved in MDSC supernatant attenuation of TGF-β1-induced myofibroblastic differentiation of mesenchymal stem cells

Ticagrelor regulates the differentiation of MDSCs after acute myocardial infarction to reduce cardiac injury

Myeloid-derived suppressor cells (MDSCs) are important participants after acute myocardial infarction (AMI), but the role of their different subtypes in AMI remains controversial. The anti-inflammatory effect of ticagrelor in AMI has been discovered. However, the detailed anti-inflammatory mechanism has not been fully demonstrated. In this study, we aimed to determine whether ticagrelor can regulate the differentiation of MDSCs into anti-inflammatory subgroups to exert anti-inflammatory effects after AMI. In vitro experiments revealed no difference in the mRNA and protein expression of P2Y12 receptors on MDSCs and macrophages. Ticagrelor promotes the differentiation of in vitro cultured MDSCs to monocytic-MDSCs (M-MDSCs). A mouse AMI model was established to investigate the anti-inflammatory effects of ticagrelor in vivo after AMI by interfering with the differentiation of MDSCs. On the first day after AMI, spleen-derived polymorphonuclear-MDSCs (PMN-MDSCs) were predominant in the circulation and infarcted heart. Ticagrelor increased the percentage of M-MDSCs in the circulation and infarcted heart of AMI mice in a dose-dependent manner, attenuated cardiac inflammation and increased cardiac contractile function. M-MDSC injection significantly decreased cardiac inflammation levels and improved cardiac function in splenectomized AMI mice compared with PMN-MDSC injection. These data point to a novel anti-inflammatory role for ticagrelor after AMI by interfering with the differentiation of MDSCs.

Tissue fibrosis induced by radiotherapy: current understanding of the molecular mechanisms, diagnosis and therapeutic advances

Cancer remains the leading cause of death around the world. In cancer treatment, over 50% of cancer patients receive radiotherapy alone or in multimodal combinations with other therapies. One of the adverse consequences after radiation exposure is the occurrence of radiation-induced tissue fibrosis (RIF), which is characterized by the abnormal activation of myofibroblasts and the excessive accumulation of extracellular matrix. This phenotype can manifest in multiple organs, such as lung, skin, liver and kidney. In-depth studies on the mechanisms of radiation-induced fibrosis have shown that a variety of extracellular signals such as immune cells and abnormal release of cytokines, and intracellular signals such as cGAS/STING, oxidative stress response, metabolic reprogramming and proteasome pathway activation are involved in the activation of myofibroblasts. Tissue fibrosis is extremely harmful to patients' health and requires early diagnosis. In addition to traditional serum markers, histologic and imaging tests, the diagnostic potential of nuclear medicine techniques is emerging. Anti-inflammatory and antioxidant therapies are the traditional treatments for radiation-induced fibrosis. Recently, some promising therapeutic strategies have emerged, such as stem cell therapy and targeted therapies. However, incomplete knowledge of the mechanisms hinders the treatment of this disease. Here, we also highlight the potential mechanistic, diagnostic and therapeutic directions of radiation-induced fibrosis.