AIM:To investigate the effects of urolithin A on motor function and muscle fibrosis in dystrophin-deficient mdx mice,a model of Duchenne muscular dystrophy.METHODS:Twelve 26-week-old SPF male dystrophin gene deficient C57BL/10ScSnJNju-Dmdem3Cd4/Gpt(mdx)mice were randomly divided into model group and urolithin A treatment group,with 6 mice in each group.Additionally,six wild-type SPF male mice were selected as the normal con-trol.The motor ability of the mice was evaluated by pole climbing test,inverted suspension test,grip strength test and en-durance test.The body mass,mitochondrial relative copy number,ATP level and malondialdehyde(MDA)level were compared among the mice in different groups.Hematoxylin-eosin staining,Masson staining and immunohistochemistry were performed to analyze the atrophy and pathological changes of the gastrocnemius muscle.RESULTS:Compared with normal control group,the mdx mice in model group exhibited significantly impaired motor function,as evidenced by pro-longed pole-climbing time(P<0.01),reduced suspension time and forelimb/hindlimb grip strength(P<0.01),and in-creased number of electrical stimuli required to induce movement(P<0.01).Additionally,mitochondrial relative copy number and ATP level were significantly decreased(P<0.01),while MDA level was significantly elevated(P<0.01).Histological analysis revealed marked inflammatory cell infiltration and extensive tissue fibrosis in the gastrocnemius mus-cle.In contrast,urolithin A treatment significantly improved motor performance(P<0.01),attenuated inflammatory cell infiltration and muscle fibrosis,increased mitochondrial copy number,restored ATP level(P<0.05),and reduced MDA level(P<0.01).CONCLUSION:Urolithin A ameliorates motor dysfunction and alleviates muscle fibrosis in mdx mice,suggesting its potential therapeutic benefits for Duchenne muscular dystrophy.

Objective:To explore the relationship between college students' Type D personality and problematic social media usage, as well as the mediating and moderating roles of cognitive flexibility.Methods:From April to July 2024, totally 489 college students were investigated using the problematic social media use scale, cognitive flexibility scale and type D personality scale. SPSS 27.0 was used for descriptive analysis, correlation analysis, moderating effect analysis and common method bias test. AMOS 26.0 was used to analyze the mediating effect relationship.Results:(1) Type D personality (26.68±11.62) was positively correlated with problematic social media usage(18.11±3.54)( r=0.46, P<0.01). (2) Flexible control played a partial mediating role in the relationship between Type D personality and problematic social media usage (effect value=0.23, 95% CI=0.12-0.33). (3) Type D personality college students’ flexible control moderated the effect of Type D personality on independent problematic social media usage( β=-0.542, P<0.05). Conclusion:The increased cognitive flexibility helps mitigate college students' levels of problematic social media usage. For college students with low cognitive flexibility, type D personality scores had a more significant effect on problematic social media usage.

AIM:To investigate the effects of urolithin A on motor function and muscle fibrosis in dystrophin-deficient mdx mice,a model of Duchenne muscular dystrophy.METHODS:Twelve 26-week-old SPF male dystrophin gene deficient C57BL/10ScSnJNju-Dmdem3Cd4/Gpt(mdx)mice were randomly divided into model group and urolithin A treatment group,with 6 mice in each group.Additionally,six wild-type SPF male mice were selected as the normal con-trol.The motor ability of the mice was evaluated by pole climbing test,inverted suspension test,grip strength test and en-durance test.The body mass,mitochondrial relative copy number,ATP level and malondialdehyde(MDA)level were compared among the mice in different groups.Hematoxylin-eosin staining,Masson staining and immunohistochemistry were performed to analyze the atrophy and pathological changes of the gastrocnemius muscle.RESULTS:Compared with normal control group,the mdx mice in model group exhibited significantly impaired motor function,as evidenced by pro-longed pole-climbing time(P<0.01),reduced suspension time and forelimb/hindlimb grip strength(P<0.01),and in-creased number of electrical stimuli required to induce movement(P<0.01).Additionally,mitochondrial relative copy number and ATP level were significantly decreased(P<0.01),while MDA level was significantly elevated(P<0.01).Histological analysis revealed marked inflammatory cell infiltration and extensive tissue fibrosis in the gastrocnemius mus-cle.In contrast,urolithin A treatment significantly improved motor performance(P<0.01),attenuated inflammatory cell infiltration and muscle fibrosis,increased mitochondrial copy number,restored ATP level(P<0.05),and reduced MDA level(P<0.01).CONCLUSION:Urolithin A ameliorates motor dysfunction and alleviates muscle fibrosis in mdx mice,suggesting its potential therapeutic benefits for Duchenne muscular dystrophy.

Objective:To explore the relationship between college students' Type D personality and problematic social media usage, as well as the mediating and moderating roles of cognitive flexibility.Methods:From April to July 2024, totally 489 college students were investigated using the problematic social media use scale, cognitive flexibility scale and type D personality scale. SPSS 27.0 was used for descriptive analysis, correlation analysis, moderating effect analysis and common method bias test. AMOS 26.0 was used to analyze the mediating effect relationship.Results:(1) Type D personality (26.68±11.62) was positively correlated with problematic social media usage(18.11±3.54)( r=0.46, P<0.01). (2) Flexible control played a partial mediating role in the relationship between Type D personality and problematic social media usage (effect value=0.23, 95% CI=0.12-0.33). (3) Type D personality college students’ flexible control moderated the effect of Type D personality on independent problematic social media usage( β=-0.542, P<0.05). Conclusion:The increased cognitive flexibility helps mitigate college students' levels of problematic social media usage. For college students with low cognitive flexibility, type D personality scores had a more significant effect on problematic social media usage.

Currently the main treatment of acute myeloid leukemia (AML) is chemotherapy combining hematopoietic stem cell transplantation. However, the unbearable side effect of chemotherapy and the high risk of life-threatening infections and disease relapse following hematopoietic stem cell transplantation restrict its application in clinical practice. Thus, there is an urgent need to develop alternative therapeutic tactics with significant efficacy and attenuated adverse effects. Here, we revealed that umbilical cord-derived mesenchymal stem cells (UC-MSC) efficiently induced AML cell differentiation by shuttling the neutrophil elastase (NE)-packaged extracellular vesicles (EVs) into AML cells. Interestingly, the generation and release of NE-packaged EVs could be dramatically increased by vitamin D receptor (VDR) activation in UC-MSC. Chemical activation of VDR by using its agonist 1α,25-dihydroxyvitamin D3 efficiently enhanced the pro-differentiation capacity of UC-MSC and then alleviated malignant burden in AML mouse model. Based on these discoveries, to evade the risk of hypercalcemia, we synthetized and identified sw-22, a novel non-steroidal VDR agonist, which exerted a synergistic pro-differentiation function with UC-MSC on mitigating the progress of AML. Collectively, our findings provided a non-gene editing MSC-based therapeutic regimen to overcome the differentiation blockade in AML.