Deficiency of Autophagy-Related Gene 5 in Keratinocytes Leads to Aggravation of Epidermal Damage in 2,4-Dinitrochlorobenzene-Induced Allergic Contact Dermatitis

Objective:The interrelationship between apoptosis and autophagy plays an important role in many pathophysiological processes,however,whether their interplay is involved in allergic contact dermatitis(ACD)has not yet been elucidated.So,we conducted this study to determine whether keratinocyte-specific autophagy-related gene 5(ATG5)deficiency can regulate apoptosis to inhibit skin damage in mice with 2,4-dinitrochlorobenzene(DNCB)-induced ACD.Methods:This study involved keratinocyte-specificAtg5 conditional knockout(cKO)mice(Krt14cre/+-Atg5flox/flox)and control mice(Krt14+/+-Atg5flox/flox).We painted DNCB on the right ear of each mouse to induce ACD.Dermatitis scoring and measurements of ear weight and thickness were performed to evaluate inflammation levels.An immunohistochemical assay was performed to analyze immune cell infiltration.Histological study and TUNEL staining were performed to compare the differences in skin lesions betweenAtg5 cKO mice and control mice.Immunofluorescence and western blotting were used to examine the levels of ATG5 and apoptosis-related protein.The results were statistically analyzed byt test.Results:After DNCB stimulation of mice ears,we observed a more severe phenotype inAtg5 cKO mice than in control mice(dermatitis score:7.500±2.588vs.3.250±0.822,P=0.003).Further analysis of ATG5 protein confirmed keratinocyte-specific ablation ofAtg5 in cKO mice and showed that DNCB did not influence ATG5 expression.Immunohistochemistry assay revealed that the infiltrated immune cells were not involved in aggravation of the phenotype of DNCB-stimulatedAtg5 cKO mice.However,the histological study(P=0.024),TUNEL staining(P=0.024),immunofluorescence(P=0.036),and western blotting showed that the increase in keratinocyte death,especially apoptosis,contributed to aggravation of the phenotype of DNCB-stimulatedAtg5 cKO mice.Conclusion:Deficiency ofAtg5 in keratinocytes increases apoptosis,aggravating skin damage in DNCB-induced ACD mice.This has no relationship with the involvement of immune cells.

Genetic polymorphisms of autophagy-related gene 5 (ATG5) rs473543 predict different disease-free survivals of triple-negative breast cancer patients receiving anthracycline- and/or taxane-based adjuvant chemotherapy

Background:Autophagy plays a crucial role in chemotherapy resistance of triple-negative breast cancer(TNBC).Hence,autophagy-related gene 5(ATG5),an essential molecule involved in autophagy regulation,is presumably associated with recurrence of TNBC.This study was aimed to investigate the potential influence of single-nucleotide polymorphisms in ATG5 on the disease-free survival(DFS)of early-stage TNBC patients treated with anthracycline-and/or taxane-based chemotherapy.Methods:We genotyped ATG5 SNP rs473543 in a cohort of 316 TNBC patients treated with anthracycline-and/or taxane-based chemotherapy using the sequenom’s MassARRAY system.Kaplan-Meier survival analysis and Cox proportional hazard regression analysis were used to analyze the association between ATG5 rs473543 genotypes and the clinical outcome of TNBC patients.Results:Three genotypes,AA,GA,and GG,were detected in the rs473543 of ATG5 gene.The distribution of ATG5 rs473543 genotypes was significantly different between patients with and without recurrence(P=0.024).Kaplan-Meier survival analysis showed that patients carrying A allele of ATG5 rs473543 had an increased risk of recurrence and shorter DFS compared with those carrying the variant genotype GG in rs473543(P=0.034).In addition,after adjust-ing for clinical factors,multivariate Cox regression analyses revealed that the AA/GA genotype of rs473543 was an independent predictor for DFS(hazard risk[HR],1.73;95%confidence interval[CI],1.04-2.87;P=0.034).In addition,DFS was shorter in node-negative patients with the presence of A allele(AA/GA)than in those with the absence of A allele(P=0.027).Conclusion:ATG5 rs473543 genotypes may serve as a potential marker for predicting recurrence of early-stage TNBC patients who received anthracycline-and/or taxane-based regimens as adjuvant chemotherapy.

Autophagy-related protein ATG5 regulates histone H2B mono-ubiquitylation by translational control of RNF20

Autophagy is an evolutionarily conserved lysosome-mediated catabolic process（Klionsky,2007）.Autophagy is believed to be essential for cell survival,especially when cells were exposed to stresses,such as nutrient starvation.

AoATG5 plays pleiotropic roles in vegetative growth,cell nucleus development,conidiation,and virulence in the nematode-trapping fungus Arthrobotrys oligospora

Autophagy is an evolutionarily conserved process in eukaryotes,which is regulated by autophagy-related genes(ATGs).Arthrobotrys oligospora is a representative species of nematode-trapping(NT)fungi that can produce special traps for nematode predation.To elucidate the biological roles of autophagy in NT fungi,we characterized an orthologous Atg protein,AoAtg5,in A.oligospora.We found that AoATG5 deletion causes a significant reduction in vegetative growth and conidiation,and that the transcript levels of several sporulation-related genes were significantly downregulated during sporulation stage.In addition,the cell nuclei were significantly reduced in theΔAoATG5 mutant,and the transcripts of several genes involved in DNA bio-synthesis,repair,and ligation were significantly upregulated.InΔAoATG5 mutants,the autophagic process was significantly impaired,and trap formation and nematocidal activity were significantly decreased.Comparative transcriptome analysis results showed that AoAtg5 is involved in the regulation of multiple cellular processes,such as autophagy,nitrogen metabolism,DNA biosynthesis and repair,and vesicular transport.In summary,our results suggest that AoAtg5 is essential for autophagy and significantly contributes to vegetative growth,cell nucleus development,sporulation,trap formation,and pathogenicity in A.oligospora,thus providing a basis for future studies focusing on related mechanisms of autophagy in NT fungi.

Interaction of the major inflammatory bowel disease susceptibility alleles in Crohn’s disease patients

AIM:To investigate the interaction of interleukin-23 receptor(IL23R)(rs1004819 and rs2201841),autophagy-related 16-like 1(ATG16L1)(rs2241880), caspase recruitment domain-containing protein 15 (CARD15)genes,and IBD5 locus in Crohn's disease(CD) patients. METHODS:A total of 315 unrelated subjects with CD and 314 healthy controls were genotyped.Interactions and specific genotype combinations of a total of eight variants were tested.The variants of IBD5locus(IGR2198a_1 rs11739135 and IGR2096a_1 rs12521868),CARD15(R702W rs2066845 and L1007fs rs2066847),ATG16L1(rs2241880)and IL23R (rs1004819,rs2201841)genes were genotyped by PCR-RFLP,the G908R(rs2066844)in CARD15 was determined by direct sequencing. RESULTS:The association of ATG16L1 T300A with CD was confirmed[P=0.004,odds ratio(OR)=1.69, 95%CI:1.19-2.41],and both IL23R variants were found to represent significant risk for the disease(P= 0.008,OR=2.05,95%CI:1.20-3.50 for rs1004819 AA;P<0.001,OR=2.97,95%CI:1.65-5.33 for rs2201841 CC).Logistic regression analysis of pairwise interaction of the inflammatory bowel disease (IBD)loci indicated that IL23R,ATG16L1,CARD15 and IBD5(IGR2198a_1)contribute independently to disease risk.We also analysed the specific combina- tions by pair of individual ATG16L1,IL23R rs1004819, rs2201841,IGR2198a_1,IGR2096a_1 and CARD15 genotypes for disease risk influence.In almost all cases,the combined risk of susceptibility pairs was higher in patients carrying two different risk-associated gene variants together than individuals with just one polymorphism.The highest OR was found for IL23R rs2201841 homozygous genotype with combination of positive CARD15 status(P<0.001,OR=9.15,95% CI:2.05-40.74). CONCLUSION:The present study suggests a cumulative effect of individual IBD susceptibility loci.