biopsy sample reduction approach to identify significant alterations of the testicular transcriptome in the presence of Y-chromosomal microdeletions that are independent of germ cell composition

• Published in: Human genetics 2010-10, Vol.128 (4), p.421-431
• Main Authors: Cappallo-Obermann, Heike, von Kopylow, Kathrein, Schulze, Wolfgang, Spiess, Andrej-Nikolai
• Format: Article
• Language: English
• Subjects: Analysis; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Biopsy; Chromosome Deletion; Chromosomes, Human, Y - genetics; Classical genetics, quantitative genetics, hybrids; Cluster Analysis; Cohort Studies; DNA microarrays; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Profiling; Gene Function; Genes; Genetic Loci; Genetic transcription; Genetics of eukaryotes. Biological and molecular evolution; Genotype & phenotype; Germ Cells - metabolism; Germ Cells - pathology; Histology; Human; Human Genetics; Humans; Infertility; Infertility, Male - genetics; Infertility, Male - pathology; Male; Meiosis - genetics; Metabolic Diseases; Molecular Medicine; Oligonucleotide Array Sequence Analysis; Original Investigation; Seminal Plasma Proteins - genetics; Sertoli Cell-Only Syndrome - genetics; Spermatogenesis; Spermatogenesis - genetics; Testis - metabolism; Testis - pathology
• ISSN: 0340-6717; 1432-1203
• DOI: 10.1007/s00439-010-0865-9

Y-chromosomal microdeletions (YCMD) are the major genetic cause of male infertility. To date, it is not known which global changes are induced by the presence of AZFc or AZFb + c deletions in the human testicular transcriptome. We investigated this question by microarray analysis in which we had to eliminate the ‘germ cell effect', i.e., the dominating effect of germ cell transcripts due to the quantitative difference in germ cell composition in samples with/without YCMD. This problem was tackled by selecting 26 samples from an initial cohort of 34 samples by their homogeneity in respect to cellular composition as obtained from gene expression clustering. This way, the ‘germ cell effect' was minimized, and a distinct ‘deletion effect' became more apparent. Several hundred genes are influenced by YCMD as shown on the three different phenotypes hypospermatogenesis, meiotic arrest, and Sertoli-cell only syndrome. We validated on an independent cohort of samples five genes by quantitative real-time PCR that are expressed in germ cells or the somatic compartment and which are exclusively altered by the presence of YCMD. We conclude that the deletion of Y-chromosomal genes has a significant effect on spermatogenesis by modulating the transcriptional network of the germ cell and somatic compartment.