Study On The Effect And Mechanism Of Cell Pyroptosis Mediated By CASP1 And CASP4 On The Sertoli Cell-only Syndrome

Background:Sertoli cell-only syndrome(SCOS)is the most serious pathological type of non-obstructive azoospermia.Testicular biopsy showed loss of spermatogenic cells and spermatogenic function of the testis.Although in the past few years,people have found that some genes may be related to the pathological development of SCOS by using gene chip and EST technology,including FANCM,TEX14,NR5A1,NANOS2,PLK4,WNK3,FANCA and so on,but these still can not achieve the purpose of explaining the disease,auxiliary diagnosis and treatment.With the development of sequencing technology,high-throughput transcriptome sequencing technology has made remarkable achievements in tumor and other fields,but the systematic analysis of mRNA in human testicular tissue using high-throughput sequencing technology has not been reported.Methods and results:In this study,we analyzed the differentially expressed genes(DEGs)based on the RNA-Seq of testicular tissue about the 9 SCOS patients and 3 OA patients with normal spermatogenic function to explore the pathogenic genes and the signal pathways.A total of 9406 DEGs were expressed(Log2|FC|≥1 and adjusted pvalue<0.05)in SCOS patients.Further,we identified the hub genes in the DEGs including 2541 up-regulated genes and 6865 down-regulated genes.We constructed a gene-gene interaction network and BRCA1,RAD51,BIRC5,CDC6,E2F1,MCM4,CDC20,TUBA4A,TUBG1,CCNA1,CCNB1,CCNA2,CHEK1,TOPBP1,MAD2L1,CDT1,HIST3H3,CDK1,BLM,CCNE1 and UBE2C were screened from the network for the down-regulated genes,and CASP4,CASPl and PLA2G4A were screened from the network for the up-regulated genes.Q-PCR analysis confirmed the key genes in these two kinds of tissues.We mainly focus on the three up-regulated genes in this study.Functional analysis showed that the up-regulated CASP1 and CASP4 were primarily involved in the process of cell pyroptosis,and we predicted that pyroptosis might be involved in the occurrence and development of SCOS.After that,we used the testicular tissue of patients to verify that the activities of CASP1 and CASP4 in testes of patients with SCOS were significantly higher than those of patients with normal spermatogenesis.Immunohistochemical results showed that CASP1 and CASP4 were mainly expressed in Sertoli cells and interstitial nuclei and around the nucleus in testicular tissues of patients with SCOS.The expressions of CASP1 and CASP4 were significantly higher than those in normal spermatogenic testes.The pyroptosis-related proteins CASP1,CASP4,GSDMD and GSDME in testes of patients with SCOS were also significantly higher than those of patients with normal spermatogenesis.At the same time,we also found that inflammatory factors IL-1β,IL-18,LDH and ROS were also significantly increased in patients with SCOS,which further proved that cell pyroptosis is one of the pathological mechanisms of the SCOS.Conclusion:The 21 core genes down-regulated in the SCOS group may be related to the loss of germ cells in SCOS patients,while the 3 up-regulated genes in the SCOS group may be related to the increase in the proportion of seminiferous tubule interstitial cells and Sertoli cells.By comparing the functional enrichment relationship between up-regulated genes,we found that cell pyroptosis mediated by CASP1 and CASP4 may be one of the pathological bases of Sertoli cell syndrome.