Effect of Spag11a gene knockout on the epididymis in mice: A histopathological and molecular analyses.

The sperm-associated antigen 11a (Spag11a) gene is exclusively expressed in the caput epididymis. Our previous studies demonstrated that small interfering RNA (siRNA)-mediated ablation of this gene resulted in increased proliferation of epididymal epithelial cells. Further, active immunization-mediated ablation of SPAG11A protein increased the susceptibility of male reproductive tract tissues to diethylnitrosamine (DEN)-induced tumorigenesis. In this study, we report that the caput epididymis of Spag11a knockout mice displayed hyperplasia and inflammation, while the caput epididymis of wild-type mice exhibited normal anatomical structure. Global transcriptome analyses in the caput epididymis of knockout mice indicated differential expression of genes involved in a variety of cellular processes. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses suggested that the absence of Spag11a may activate microRNAs associated with cancer, chemical carcinogenesis-receptor activation, and chemical carcinogenesis-DNA adducts pathways; which may contribute to the promotion of tumorigenesis in the epididymis. The susceptibility of caput epididymis to chemically induced carcinogenesis in Spag11a knockout mice was analyzed. Histological analyses indicated that while the epididymis of wild-type mice did not show any signs of tumorigenesis, knockout mice displayed hyperplasia, anaplasia, dysplasia, neoplasia, and inflammation in the caput epididymis. Our results provide concrete evidence that deletion of Spag11a induces histopathological and molecular changes that contribute to tumorigenesis. It is possible that the expression of Spag11a gene could be one of the reasons for the rarity of epididymal cancers. The involvement of an epididymal gene in tumorigenesis is being demonstrated for the first time.

Tlr1-13, Nod1/2 and antimicrobial gene expression in the epididymis and testis of rats with alloxan-induced diabetes.

Pattern recognition receptors (PRRs) such as toll-like receptors (TLRs) and nuclear oligomerization domain (NOD) receptors along with antimicrobial proteins and peptides (AMPs) are crucial for innate immunity. The pathology of insulin-dependent diabetes mellitus is associated with the disrupted expression of TLRs, NODs and AMPs in the kidney, lungs and other organs. However, such a relation in the male reproductive tract is not yet investigated. In this study, we analysed the expression pattern of Tlr1-13, Nod1/2 receptors and AMPs (ß-defensins and defensin-like proteins of the Sperm-Associated Antigen 11 (Spag11) family) in the male reproductive tissues (caput, cauda and testis) obtained from diabetic or insulin-treated diabetic or untreated control rats. Alterations in the expression pattern of Tlr1-13, Nod 1/ 2, Defb1, 2, 21, 24, 27, 30 and Spag11a/ c/ t were observed under diabetic conditions. Administration of insulin to diabetic rats could modulate the expression pattern of only some these genes. Results of our study indicate perturbed gene expression profile of Tlrs, Nod1/2, Defbs and Spag11 isoforms in the epididymis and testis of diabetic rats, and this could be one of the important reasons for the increased risk of infections in the male genital tract.

Characterization of SPINK2, SPACA7 and PDCL2: Effect of immunization on fecundity, sperm function and testicular transcriptome.

Testicular factors play a vital role in spermatogenesis. We characterized the functional role of rat Spink2, Spaca7 and Pdcl2 genes. Their primary, secondary and tertiary structure were deduced in silico. The genes of rat Spink2, Spaca7 and Pdcl2 mRNA were predominantly expressed in the testis. SPINK2, SPACA7 and PDCL2 protein expression was evident in all the cell types of testis and on spermatozoa. Ablation of each of these proteins by active immunization resulted in reduced fecundity and sperm count. Damage to the anatomical architecture of testis and epididymis was evident. In SPINK2 immunized rats, 283 genes were differentially regulated while it was 434 and 872 genes for SPACA7 and PDCL2 respectively. Genes that were differentially regulated in the testis of SPINK2 immunized rats primarily belonged to extracellular exosome formation, extracellular space and response to drugs. SPACA7 ablation affected genes related to extracellular space, oxidation-reduction processes, endoplasmic reticulum membrane and response to drugs. Differential gene expression was observed for nuclear function, protein binding and positive regulation of transcription from RNA polymerase II promoter in testis of PDCL2 immunized rats. Results of our study demonstrate the role of SPINK2, SPACA7 and PDCL2 in spermatogenesis and in important molecular processes that may dictate testicular function and other physiological responses as well.