The Founder Strains of the Collaborative Cross Express a Complex Combination of Advantageous and Deleterious Traits for Male Reproduction

Surveys of inbred strains of mice are standard approaches to determine the heritability and range of phenotypic variation for biomedical traits. In addition, they may lead to the identification of novel phenotypes and models of human disease. Surprisingly, male reproductive phenotypes are among the least-represented traits in the Mouse Phenome Database. Here we report the results of a broad survey of the eight founder inbred strains of both the Collaborative Cross (CC) and the Diversity Outbred populations, two new mouse resources that are being used as platforms for systems genetics and sources of mouse models of human diseases. Our survey includes representatives of the three main subspecies of the house mice and a mix of classical and wild-derived inbred strains. In addition to standard staples of male reproductive phenotyping such as reproductive organ weights, sperm counts, and sperm morphology, our survey includes sperm motility and the first detailed survey of testis histology. As expected for such a broad survey, heritability varies widely among traits. We conclude that although all eight inbred strains are fertile, most display a mix of advantageous and deleterious male reproductive traits. The CAST/EiJ strain is an outlier, with an unusual combination of deleterious male reproductive traits including low sperm counts, high levels of morphologically abnormal sperm, and poor motility. In contrast, sperm from the PWK/PhJ and WSB/EiJ strains had the greatest percentages of normal morphology and vigorous motility. Finally, we report an abnormal testis phenotype that is highly heritable and restricted to the WSB/EiJ strain. This phenotype is characterized by the presence of a large, but variable, number of vacuoles in at least 10% of the seminiferous tubules. The onset of the phenotype between 2 and 3 wk of age is temporally correlated with the formation of the blood-testis barrier. We speculate that this phenotype may play a role in high rates of extinction in the CC project and in the phenotypes associated with speciation in genetic crosses that use the WSB/EiJ strain as representative of the Mus muculus domesticus subspecies

Implication des sérine-protéases et des serpin dans la physiologie du testicule (incidence d'une exposition in utero aux dioxines sur la différenciation gonadique)

Le testicule est un tissu dynamique qui se caractérise par de multiples épisodes de migrations cellulaires et de restructurations tissulaires tout au long du développement et de la vie adulte. Ce projet s'est orienté sur le rôle des sérine-protéases et leurs inhibiteurs, les SERPIN, dans la physiologie testiculaire. Nous montrons que la SERPINA5 est exprimée à partir de 12,5 jpc dans les gonades mâles. Elle est localisée dans les cellules de Leydig et l'urokinase est une de ses protéases cibles. La SERPINA5 est aussi localisée dans les cellules germinales du testicule post-natal et adulte. Par ailleurs, nous démontrons que l'hormone trophique LH modifie l'activité protéolytique leydigienne, ce qui pourrait, en modulant l'espace extracellulaire, influer sur l'activité stéroïdogène de la cellule de Leydig. Nous avons également participé à une étude sur l'impact d'une exposition in utero aux dioxines sur l'acquisition de la fonction de reproduction chez le rat mâleLYON1-BU.Sciences (692662101) / SudocSudocFranceF

The mouse testis is the source of various serine proteases and serine proteinase inhibitors (SERPINs): Serine proteases and SERPINs identified in Leydig cells are under gonadotropin regulation

E-mail: [email protected] audienceThe occurrence of various serine proteinases and serine proteinases inhibitors (SERPINs) was investigated by RT-PCR in whole testes of 1-, 3-, and 8-wk-old mice in crude and enriched germ cell fractions, mouse Leydig tumor cells (mLTC-1), and primary cultures of 3- and 8-wk-old enriched fractions of Leydig cells and 3-wk-old Sertoli cells. New members were identified in the testis protease repertoire. Within the Leydig repertoire, a PCR product was found for plasminogen activators urokinase plasminogen activator (uPA) and tissue plasminogen activator (8-wk-old cells), matriptase-2 (mLTC-1), kallikrein-21, SERPINA5, SERPINB2 (primary cultures), and serine peptidase inhibitor Kunitz type 2 (SPINT2). The gonadotropin regulation was explored by semiquantitative RT-PCR, using steroidogenic acute regulatory protein (StAR) as a positive control. Matriptase-2, kallikrein-21, SPINT2, and SERPINA5 were down-regulated, whereas uPA and its receptor were up-regulated by human chorionic gonadotropin (hCG) via cAMP in the mLTC-1 cells. Positive effects were observed transiently after 1-8 h of hCG exposure, and negative effects, first evidenced after 6 h, lasted 48 h. The hCG-induced effects were confirmed in primary cultures. In addition, SERPINB2 was augmented by hCG in primary cultures. Addition of either trypsin or protease inhibitors did not alter the hCG-induced surge of StAR. Because hCG regulated proteases and SERPINs (whereas testosterone did not), it could alter the proteolytic balance of Leydig cells and consequently the metabolism of extracellular matrix components. Therefore, even though a direct interplay between the early hCG-induced surge of uPA and StAR is unlikely, our data together with the literature suggest that extracellular matrix proteins alter Leydig cell steroidogenesis

A comprehensive survey of the laminins and collagens type IV expressed in mouse Leydig cells and their regulation by LH/hCG.

International audienceExtracellular matrix (ECM) proteins have been shown to alter Leydig cell steroidogenesis in vitro, substantiating the hypothesis that Leydig cell steroidogenic activity and matrix environment are interdependent events. However, the nature of the ECM components synthesized by Leydig cells and their regulation by LH/human chorionic gonadotropin (hCG) remain unknown. Here, we examine the occurrence of the 11 laminin subunits and the 6 alpha chains of collagen IV (COL4A1-6) by RT-PCR in Leydig cells cultured with or without LH/hCG. Leydig cells were a tumor Leydig cell line (mLTC-1) or 8-week-old mice Leydig cells. Based on PCR data, it is suggested that normal Leydig cells may synthesize a maximum of 11 laminin heterotrimers and the 6 alpha chains of collagen IV. They also may synthesize various proteases and inhibitors of the metzincin family. The mLTC-1 cells have a limited repertoire as compared with normal Leydig cells. Interestingly, none of the ten proteases and inhibitors monitored is under LH-hCG regulation whereas every protease and inhibitor of the serine protease family yet identified in Leydig cells is under gonadotropin regulation. In addition, a few laminin and collagen subunit genes are regulated by LH/hCG. These are laminins alpha3 and gamma3 (Lama3 and Lamc3), Col4a3, and Col4a6, which are negatively regulated by LH/hCG in both Leydig cell types, and Col4a4, which was downregulated in primary cultures but not in mLTC-1 cells. Collectively, the present study suggests that Leydig cells modulate in a selective fashion their matrix environment in response to their trophic hormone. This may alter the steroidogenic outcome of Leydig cells

The Founder Strains of the Collaborative Cross Express a Complex Combination of Advantageous and Deleterious Traits for Male Reproduction

Surveys of inbred strains of mice are standard approaches to determine the heritability and range of phenotypic variation for biomedical traits. In addition, they may lead to the identification of novel phenotypes and models of human disease. Surprisingly, male reproductive phenotypes are among the least-represented traits in the Mouse Phenome Database. Here we report the results of a broad survey of the eight founder inbred strains of both the Collaborative Cross (CC) and the Diversity Outbred populations, two new mouse resources that are being used as platforms for systems genetics and sources of mouse models of human diseases. Our survey includes representatives of the three main subspecies of the house mice and a mix of classical and wild-derived inbred strains. In addition to standard staples of male reproductive phenotyping such as reproductive organ weights, sperm counts, and sperm morphology, our survey includes sperm motility and the first detailed survey of testis histology. As expected for such a broad survey, heritability varies widely among traits. We conclude that although all eight inbred strains are fertile, most display a mix of advantageous and deleterious male reproductive traits. The CAST/EiJ strain is an outlier, with an unusual combination of deleterious male reproductive traits including low sperm counts, high levels of morphologically abnormal sperm, and poor motility. In contrast, sperm from the PWK/PhJ and WSB/EiJ strains had the greatest percentages of normal morphology and vigorous motility. Finally, we report an abnormal testis phenotype that is highly heritable and restricted to the WSB/EiJ strain. This phenotype is characterized by the presence of a large, but variable, number of vacuoles in at least 10% of the seminiferous tubules. The onset of the phenotype between 2 and 3 wk of age is temporally correlated with the formation of the blood-testis barrier. We speculate that this phenotype may play a role in high rates of extinction in the CC project and in the phenotypes associated with speciation in genetic crosses that use the WSB/EiJ strain as representative of the Mus muculus domesticus subspecies

Male Infertility Is Responsible for Nearly Half of the Extinction Observed in the Mouse Collaborative Cross.

The goal of the Collaborative Cross (CC) project was to generate and distribute over 1000 independent mouse recombinant inbred strains derived from eight inbred founders. With inbreeding nearly complete, we estimated the extinction rate among CC lines at a remarkable 95%, which is substantially higher than in the derivation of other mouse recombinant inbred populations. Here, we report genome-wide allele frequencies in 347 extinct CC lines. Contrary to expectations, autosomes had equal allelic contributions from the eight founders, but chromosome X had significantly lower allelic contributions from the two inbred founders with underrepresented subspecific origins (PWK/PhJ and CAST/EiJ). By comparing extinct CC lines to living CC strains, we conclude that a complex genetic architecture is driving extinction, and selection pressures are different on the autosomes and chromosome X Male infertility played a large role in extinction as 47% of extinct lines had males that were infertile. Males from extinct lines had high variability in reproductive organ size, low sperm counts, low sperm motility, and a high rate of vacuolization of seminiferous tubules. We performed QTL mapping and identified nine genomic regions associated with male fertility and reproductive phenotypes. Many of the allelic effects in the QTL were driven by the two founders with underrepresented subspecific origins, including a QTL on chromosome X for infertility that was driven by the PWK/PhJ haplotype. We also performed the first example of cross validation using complementary CC resources to verify the effect of sperm curvilinear velocity from the PWK/PhJ haplotype on chromosome 2 in an independent population across multiple generations. While selection typically constrains the examination of reproductive traits toward the more fertile alleles, the CC extinct lines provided a unique opportunity to study the genetic architecture of fertility in a widely genetically variable population. We hypothesize that incompatibilities between alleles with different subspecific origins is a key driver of infertility. These results help clarify the factors that drove strain extinction in the CC, reveal the genetic regions associated with poor fertility in the CC, and serve as a resource to further study mammalian infertility. Genetics 2017 Jun; 206(2):557-72

Cuadernos de pedagogía

Se proponen, para su análisis, una serie de escenarios y experiencias del mapa educativo y de la formación. Todas ellas tienen en común que se presentan como redes o comunidades que dedican su actividad o parte de ella a la formación de profesorado. Se analizan las siguientes experiencias: Coordinació Escoles 0-12, Colectivo de Jóvenes Educadores del MRP Escuela Abierta, Fedicaria, Seminario de Ciudadanía Crítica del la Universitat Jaime I, Nova Escola Galega, Asociación Centro de Filosofía para niños, Red IRES: investigación y renovación escolar, Grup de Projectes del País Valenciá, Escuela de papel, Averroes: Red Telemática Educativa de Andalucía, Secretariat dïEscola Rural de Catalunya.CataluñaMadrid (Comunidad Autónoma). Servicio de Formación del Profesorado. CRIF Las Acacias; Calle General Ricardos, 179; 28025 Madrid; Tel. +34915250893; Fax +34914660991; [email protected]