PRRSV infection activates NLRP3 inflammasome through inducing cytosolic mitochondrial DNA stress.

Porcine reproductive and respiratory syndrome virus (PRRSV) infection causes severe interstitial pneumonia and inflammatory response in piglets and growing pigs. IL-1ß is implicated in PRRSV-mediated inflammatory response and the pathogenesis of PRRSV infection. Mitochondria are critical intracellular organelles which is served as signaling platform for antiviral immunity response to participate in immune response of virus infection. The role of mitochondria in PRRSV-mediated inflammatory response and the pathogenesis of PRRSV infection has not been elucidated. Here, our data suggested that PRRSV infection facilitates mitochondrial dysfunction, which induces cytosolic mitochondrial DNA (mtDNA) stress and ROS accumulation, severally activates the NLRP3 inflammasome and NF-κB signaling pathway, and consequently stimulates IL-1ß production in PAMs. Furthermore, mtDNA degradation by DNase I abrogates the activation of NLRP3 inflammasome and IL-1ß secretion during PRRSV infection. Scavenging ROS significantly inhibits NF-κB signaling activation and the subsequently transcription and secretion of IL-1ß. In conclusion, our results indicate that cytosolic mtDNA stress and ROS accumulation after PRRSV infection-induced mitochondrial dysfunction activate NLRP3 inflammasome and NF-κB signaling pathway to promote IL-1ß production, revealing a new strategy for vaccine and drug development to PRRSV.

The influence of "small private online course + flipped classroom" teaching on physical education students' learning motivation from the perspective of self-determination theory.

Objective: The study aimed to enhance the learning motivation of college physical education students and improve their learning outcomes. Based on the perspective of the self-determination theory, this study explores the influence of "Small Private Online Course (SPOC) + flipped classroom" teaching on the learning motivation of students majoring in physical education and profoundly analyzes the influencing factors and promotion paths of learning motivation using this model. Materials and methods: A total of four classes (64 students) of physical education majors in a university were selected and randomly divided into an experimental group (34 students) and a control group (30 students). The experimental group received "SPOC + flipped classroom" teaching, the control group received traditional teaching. Before and after the 16-week intervention, learning motivation, teacher support perception, basic psychological need satisfaction, and academic emotions of the 64 students were measured, and the data were analyzed by repeated-measures analysis of variance and partial least square regression. Results: (1) The instructional intervention reduced non-regulation, external regulation, and introjected regulation, while increased identified regulation, intrinsic regulation, and self-determination levels in the students. The levels of non-regulation, external regulation, identified regulation, and self-determination were also significantly different from those of the control group. (2) After the intervention, the scores of support for autonomy, support for competence, support for relatedness, and need for relatedness in the experimental group were significantly higher than those in the control group. (3) Support for autonomy, support for competence, support for relatedness, need for competence and need for relatedness positively predicted the self-determination level, and intrinsic regulation and identified regulation negatively predicted non-regulation, external regulation, and introjected regulation. Conclusion: "SPOC + flipped classroom" teaching has a positive impact on students' learning motivation of basketball skills and promotes students' motivation autonomy. The improvement of support for autonomy, support for competence, support for relatedness, need for competence, and need for relatedness may be related to the improvement of learning motivation of college students majoring in Physical Education (PE). "SPOC + flipped classroom" teaching enables students to obtain more demand satisfaction by giving them more demand support, while demand support and demand satisfaction can promote the internalization of learning motivation so that students can maintain high autonomy motivation.