Objective To explore the underlying mechanisms by which time-restricted feeding(TRF)attenuates dextran sodium sulfate(DSS)-induced colitis in mice via modulation of regenerating islet-derived protein 3 gamma(Reg3γ)expression and gut microbiota.Methods Six-week-old C57BL/6 mice were stratified by body weight and randomized into ad libitum feeding(AL)and TRF groups(n=7).The AL mice were given unrestricted food access,whereas the TRF mice were allowed feeding only during 00:00 and 08:00 daily,for totally 4 weeks.Mouse colitis model was induced at the fourth week by adding 2.5%dextran sodium sulfate(DSS)in drinking water for 6 d.Disease severity and the effects of TRF were assessed with disease activity index(DAI)scoring,colon length measurement,HE staining and histopathological scoring,and mRNA expression levels of regenerating islet-derived 3 gamma(Reg3g)and inflammatory cytokines in colonic tissues.Another 14 mice were randomized into AL plus antibiotic cocktail(AL+ABX)and TRF plus antibiotic cocktail(TRF+ABX)groups,with 7 animals in each group.ABX was administered to deplete gut microbiota and evaluate the microbiota dependence of TRF in attenuating colitis.Fecal samples from AL and TRF mice were analyzed by 16S ribosomal RNA sequencing(16S rRNA-seq),and serum lipopolysaccharide(LPS)level was measured.The colonic epithelial cells were collected for RNA-seq.Results After modeling,the AL mice exhibited typical colitis symptoms,such as weight loss,diarrhea,and hematochezia.TRF intervention significantly attenuated these above symptoms,with lower DAI scores from day 4 post-modeling(P<0.001),reduced colon shortening(P<0.01),preserved tissue architecture,and decreased inflammation.RT-qPCR analysis showed that TRF down-regulated colonic mRNA expression levels of Reg3g and pro-inflammatory cytokines(IL-1 β,IL-6,TNF-α)(P<0.05)while up-regulated that of anti-inflammatory factor IL-10(P<0.000 1)when compared with the corresponding levels in AL mice.ABX treatment led no significant differences between the AL+ABX and TRF+ABX groups in term of DAI score,colon length,or histopathology.Obviously down-regulated Reg3g was observed in the TRF+ABX group than the AL+ABX group(P<0.05),whereas L-1β,IL-6,TNF-α and IL-10 showed no notable changes.16S rRNA-seq revealed that TRF markedly reshaped gut microbiota composition,with increased Gram-positive bacterial abundance,reduced Gram-negative bacteria,with concomitant lower serum LPS level(P<0.001).RNA-seq also indicated significant suppression of NF-κB and other inflammation-related signaling pathways in the TRF group.Conclusion TRF attenuates DSS-induced colitis in mice by downr-egulating Reg3γ expression,reshaping gut microbiota,and reducing serum LPS level,and thereby suppressing NF-κB-mediated inflammatory signaling pathways.

Objective:Analyzing the relationship between negative life events and depressive symptoms in university freshmen,and the mediating effects of neuroticism and the moderating role of exercise frequency.Meth-ods:A sampling of 8 079 university freshmen,and the Patient Health Questionnaire was used to assess depressive symptoms,the Eysenck Personality Inventory-Neuroticism subscale to assess neuroticism,the self-administered questionnaire to assess the number of negative life events that the participants had experienced and the exercise fre-quency.Model 4 in the Process plug-in was used to test the mediating effect of neuroticism,and Model 7 to test the moderating role of exercise frequency.Results:The numbers of negative life events were positively correlated with the depressive symptoms scores(r=0.16,P＜0.01),and were positively correlated with the neuroticism scores(r=0.26,P＜0.01).The neuroticism scores were positively correlated with the depressive symptoms scores(r=0.52,P＜0.01).Neuroticism score partially mediated between negative life events and depressive symptoms score,with a mediating effect of 78.4％,and exercise frequency score moderated between negative life events and neuroti-cism scores(β=-0.05,P=0.032).Conclusion:Negative life events are associated with depressive symptoms,neuroticism plays a mediating role,and exercise frequency could moderate negative life events and neuroticism.

Pulmonary fibrosis (PF) is the pathological structure of incurable fibroproliferative lung diseases that are attributed to the repeated lung injury-caused failure of lung alveolar regeneration (LAR). Here, we report that repetitive lung damage results in a progressive accumulation of the transcriptional repressor SLUG in alveolar epithelial type II cells (AEC2s). The abnormal increased SLUG inhibits AEC2s from self-renewal and differentiation into alveolar epithelial type I cells (AEC1s). We found that the elevated SLUG represses the expression of the phosphate transporter SLC34A2 in AEC2s, which reduces intracellular phosphate and represses the phosphorylation of JNK and P38 MAPK, two critical kinases supporting LAR, leading to LAR failure. TRIB3, a stress sensor, interacts with the E3 ligase MDM2 to suppress SLUG degradation in AEC2s by impeding MDM2-catalyzed SLUG ubiquitination. Targeting SLUG degradation by disturbing the TRIB3/MDM2 interaction using a new synthetic staple peptide restores LAR capacity and exhibits potent therapeutic efficacy against experimental PF. Our study reveals a mechanism of the TRIB3-MDM2-SLUG-SLC34A2 axis causing the LAR failure in PF, which confers a potential strategy for treating patients with fibroproliferative lung diseases.