Proteomic and genomic dissection of human sperm chromatin: epigenetic potential and involvement in male infertility — ASN Events
  1. Schedule
  2. Session 4.1: Molecular mechanisms that regulate sperm function
  3. Proteomic and genomic dissection of human sperm chromatin: epigenetic potential and involvement in male infertility

Proteomic and genomic dissection of human sperm chromatin: epigenetic potential and involvement in male infertility (#23)

Rafael Oliva 1 , Judit Castillo 1 , Ruben Azpiazu 1 , Alexandra Amaral 1 2 , Carla Paiva 1 2 , Claudio Attardo Parrinello 1 , Tanya Vavouri 3 , Josep Maria Estanyol 4 , Josep Lluís Ballescà 5
  1. Human Genetics Research Group, Faculty of Medicine, Biochemistry and Molecular Genetics Service, University of Barcelona, Hospital Clinic from Barcelona, and Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
  2. PhD Programme in Experimental Biology and Biomedicine, CNC-Center for Neuroscience and Cell Biology and Institute for Interdisciplinary Research, and Biology of Reproduction and Stem Cell Group, CNC, University of Coimbra, Coimbra, Portugal
  3. Institute of Predictive and Personalized Medicine of Cancer (IMPPC), Barcelona, Spain
  4. Proteomics Unit, Scientific and Technical Centers of the University of Barcelona (CCiTUB), Barcelona, Spain
  5. Clinic Institute of Gynaecology, Obstetrics and Neonatology, Hospital Clinic, Barcelona, Spain

It is known that the majority of the sperm cell DNA is packaged by protamines while a small fraction (~8%) remains associated with nucleosomes enriched at loci of developmental importance1 2 3 . However, the repertoire of proteins in different sperm chromatin fractions had not yet been explored4 5 6 7 . Therefore, our initial goal has been to perform a detailed proteomic and genomic characterization of the sperm chromatin in order to increase the epigenetic knowledge of the male germ cell8 . A complementary goal has been aimed at determining whether quantitative alterations in chromatin proteins were present in normozoospermic sperm samples from infertile patients. Two different sperm chromatin fractions were obtained from sperm nuclei through the dissociation of histones using a saline treatment and the proteins were identified by mass spectrometry. Sperm DNA was additionally subjected to fractionation by endonucleases and deep genome sequenced confirming appropriate dissection of the sperm chromatin.  Proteomic analyses showed the identification of 475 proteins in the soluble fraction (SF) and 20 in the insoluble fraction (IF). Our results indicate that the sperm cell chromatin delivers to the offspring a rich combination of histone variants, transcription factors, chromatin-associated and chromatin-modifying proteins differing in chromatin affinity, which may be involved in the regulation of histone-bound paternal genes after fertilization. We also explored whether quantitative alterations in chromatin proteins were present in normozoospermic sperm samples from infertile patients through tandem mass tag (TMT) differential proteomics and protein identification through LC-MS/MS. The differential proteomic results suggest that alterations in the proteins involved in chromatin assembly and metabolism may originate epigenetic errors  during spermatogenesis , resulting in inaccurate sperm epigenetic signatures, which could ultimately prevent embryonic development. Funded by Ministerio de Economía y Competitividad (BFU2009-07718 and PI13/00699), European Union (ITN-GA-2011-289880) and Fundación Salud 2000 (SERONO13-015).

  1. Oliva, R., de Mateo, S., and Estanyol, J. M. Sperm cell proteomics. Proteomics 2009;9:1004–1017.
  2. Arpanahi A, Brinkworth M, Iles D, Krawetz SA, Paradowska A, Platts AE, et al., Endonuclease-sensitive regions of human spermatozoal chromatin are highly enriched in promoter and CTCF binding sequences. Genome Res 2009;19:1338–1349.
  3. Hammoud SS, Nix DA, Zhang H, Purwar J, Carrell DT, Cairns BR. Distinctive chromatin in human sperm packages genes for embryo development. Nature 2009;460:473–478.
  4. Amaral A, Castillo J, Ramalho-Santos J, Oliva R. The combined human sperm proteome: cellular pathways and implications for basic and clinical science. Hum Reprod Update 2014;20:40-62.
  5. de Mateo S, Castillo J, Estanyol JM, Ballescà JL, Oliva R. Proteomic characterization of the human sperm nucleus. Proteomics 2011a;11:2714–2726.
  6. Baker MA, Naumovski N, Hetherington L, Weinberg A, Velkov T, Aitken RJ. Head and flagella subcompartmental proteomic analysis of human spermatozoa. Proteomics 2013;13:61–74.
  7. Wang G, Guo Y, Zhou T, Shi X, Yu J, Yang Y, et al. In-depth proteomic analysis of the human sperm reveals complex protein compositions. J Proteomics 2013;79:114–122.
  8. Castillo J, Amaral A, Oliva R. Sperm nuclear proteome and its epigenetic potential. Andrology 2013; Dec 10. Epub ahead of print.