No abstract

Oxidized low-density lipoprotein (oxLDL)-induced injury and apoptosis of endothelial cells are important initial events in numerous cardiovascular diseases. Following activation by oxLDL, monocytes adhere to endothelial cells, migrate into the subendothelial spaces and then undergo differentiation into macrophages, which subsequently induces the formation of atherosclerotic lesions. However, the mechanisms underlying the activation of macrophage differentiation by oxLDL-treated endothelial cells remain unclear. In the present study, it was demonstrated that exosomal metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) was increased in oxLDL-treated human umbilical vein endothelial cells. When co-cultured with monocytes, exosomes extracted from oxLDL-treated HUVECs were endocytosed. Furthermore, exosomes derived from oxLDL-treated endothelial cells were revealed to promote M2 macrophage polarization, as reverse transcription-quantitative polymerase chain reaction, western blotting and ELISA analyses demonstrated increases in the expression of M2 macrophage markers, including macrophage mannose receptor 1 (also termed CD206), arginase-1 and interleukin (IL)-10, and decreases in the expression of the M1 macrophage marker, IL-12. Furthermore, the suppression of MALAT1 expression in monocytes was demonstrated to reverse exosome-mediated M2 macrophage polarization. In conclusion, the results of the present study revealed a novel mechanism underlying the onset of atherogenesis associated with endothelial cells and macrophages: Exosomal MALAT1 derived from oxLDL-treated endothelial cells promoted M2 macrophage polarization. This result may provide a novel scientific basis for the understanding of atherosclerosis progression.

Background: The novel coronavirus disease 2019 (COVID-19) pandemic has tested the ability of universities to provide a high-quality, safe educational experience for students due to campuses shutting down. As a result, online learning could shift from a traditional classroom teaching mode and make education accessible to students. Previous studies have used individual online teaching cases to exploit a variety of online learning tools to ensure the continuation of medical education during this difficult time in China. However, for the first time, we have conducted a systematic review of local online teaching approaches, existing challenges, and potential solutions.Purpose: We present the issues and experience of conducting online medical teaching practices in China with the aim of communicating them to our peers in other countries or regions when examining the transition to e-learning during the COVID-19 pandemic and beyond.Methods: We searched the keywords below from public databases and reviewed relevant publications reporting on medical online teaching in China during the COVID-19 pandemic to analyze and summarize the online tools, modalities, and challenges.Results: We listed common online teaching tools and described a variety of online teaching modalities, as well as possible challenges. We also discussed potential solutions for those challenges, as well as the impact of the transition to online teaching on traditional education.Conclusion: By investigating local online medical teaching in China, we present useful tools and modalities that have been successfully exploited in education during the difficult time of COVID-19, although some challenges remain. The exploration of the transition to online teaching or learning will likely continue to have a profound impact on traditional classroom teaching.