Neurofibromin haploinsufficiency results in altered spermatogenesis in a mouse model of neurofibromatosis type 1

• Published in: PloS one 2018-12, Vol.13 (12), p.e0208835-e0208835
• Main Authors: Chohan, Harleen, Esfandiarei, Mitra, Arman, Darian, Van Raamsdonk, Catherine D, van Breemen, Cornelis, Friedman, Jan M, Jett, Kimberly A
• Format: Article
• Language: English
• Subjects: Anesthesiology; Animals; Biology; Biology and Life Sciences; Care and treatment; Cell division; Chromosomes; Disease Models, Animal; Endocrinology; Epithelium; Extracellular Signal-Regulated MAP Kinases - genetics; Extracellular Signal-Regulated MAP Kinases - metabolism; Females; Fertility; Gene mutation; Genetic disorders; Germ cells; Haploinsufficiency; Humans; Kinases; Male; Males; Medicine and Health Sciences; Mice; Mice, Mutant Strains; Morphology; Morphometry; Mutation; Neurofibromatosis; Neurofibromatosis 1 - genetics; Neurofibromatosis 1 - metabolism; Neurofibromatosis 1 - pathology; Neurofibromin 1; Neurofibromin 1 - genetics; Neurofibromin 1 - metabolism; Neurological disorders; Pharmacology; Proteins; ras Proteins - genetics; ras Proteins - metabolism; Recklinghausen's disease; Research and Analysis Methods; Seminiferous Epithelium - metabolism; Seminiferous Epithelium - pathology; Specialization; Sperm; Spermatids; Spermatids - metabolism; Spermatids - pathology; Spermatogenesis; Studies; Testes; Tumors
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0208835

The fertility of men with neurofibromatosis 1 (NF1) is reduced. Despite this observation, gonadal function has not been examined in patients with NF1. In order to assess the role of reduced neurofibromin in the testes, we examined testicular morphology and function in an Nf1+/- mouse model. We found that although Nf1+/- male mice are able to reproduce, they have significantly fewer pups per litter than Nf1+/+ control males. Reduced fertility in Nf1+/- male mice is associated with disorganization of the seminiferous epithelium, with exfoliation of germ cells and immature spermatids into the tubule lumen. Morphometric analysis shows that these alterations are associated with decreased Leydig cell numbers and increased spermatid cell numbers. We hypothesized that hyper-activation of Ras in Nf1+/- males affects ectoplasmic specialization, a Sertoli-spermatid adherens junction involved in spermiation. Consistent with this idea, we found increased expression of phosphorylated ERK, a downstream effector of Ras that has been shown to alter ectoplasmic specialization, in Nf1+/- males in comparison to control Nf1+/+ littermates. These data demonstrate that neurofibromin haploinsufficiency impairs spermatogenesis and fertility in a mouse model of NF1.