Connexin40 regulates platelet function

The presence of multiple connexins was recently demonstrated in platelets, with notable expression of Cx37. Studies with Cx37-deficient mice and connexin inhibitors established roles for hemichannels and gap junctions in platelet function. It was uncertain, however, whether Cx37 functions alone or in collaboration with other family members through heteromeric interactions in regulation of platelet function. Here we report the presence and functions of an additional platelet connexin, Cx40. Inhibition of Cx40 in human platelets or its deletion in mice reduces platelet aggregation, fibrinogen binding, granule secretion and clot retraction. The effects of the Cx37 inhibitor 37,43Gap27 on Cx40-/- mouse platelets and of the Cx40 inhibitor 40Gap27 on Cx37-/- mouse platelets revealed that each connexin is able to function independently. Inhibition or deletion of Cx40 reduces haemostatic responses in mice, indicating the physiological importance of this protein in platelets. We conclude that multiple connexins are involved in regulating platelet function, thereby contributing to haemostasis and thrombosis

Wdr74 Is Required for Blastocyst Formation in the Mouse

Preimplantation is a dynamic developmental period during which a combination of maternal and zygotic factors program the early embryo resulting in lineage specification and implantation. A reverse genetic RNAi screen in mouse embryos identified the WD Repeat Domain 74 gene (Wdr74) as being required for these critical first steps of mammalian development. Knockdown of Wdr74 results in embryos that develop normally until the morula stage but fail to form blastocysts or properly specify the inner cell mass and trophectoderm. In Wdr74-deficient embryos, we find activated Trp53-dependent apoptosis as well as a global reduction of RNA polymerase I, II and III transcripts. In Wdr74-deficient embryos blocking Trp53 function rescues blastocyst formation and lineage differentiation. These results indicate that Wdr74 is required for RNA transcription, processing and/or stability during preimplantation development and is an essential gene in the mouse

Ouabain Stimulates a Na+/K+-ATPase-Mediated SFK-Activated Signalling Pathway That Regulates Tight Junction Function in the Mouse Blastocyst

The Na+/K+-ATPase plays a pivotal role during preimplantation development; it establishes a trans-epithelial ionic gradient that facilitates the formation of the fluid-filled blastocyst cavity, crucial for implantation and successful pregnancy. The Na+/K+-ATPase is also implicated in regulating tight junctions and cardiotonic steroid (CTS)-induced signal transduction via SRC. We investigated the expression of SRC family kinase (SFK) members, Src and Yes, during preimplantation development and determined whether SFK activity is required for blastocyst formation. Embryos were collected following super-ovulation of CD1 or MF1 female mice. RT-PCR was used to detect SFK mRNAs encoding Src and Yes throughout preimplantation development. SRC and YES protein were localized throughout preimplantation development. Treatment of mouse morulae with the SFK inhibitors PP2 and SU6656 for 18 hours resulted in a reversible blockade of progression to the blastocyst stage. Blastocysts treated with 10−3 M ouabain for 2 or 10 minutes and immediately immunostained for phosphorylation at SRC tyr418 displayed reduced phosphorylation while in contrast blastocysts treated with 10−4 M displayed increased tyr418 fluorescence. SFK inhibition increased and SFK activation reduced trophectoderm tight junction permeability in blastocysts. The results demonstrate that SFKs are expressed during preimplantation development and that SFK activity is required for blastocyst formation and is an important mediator of trophectoderm tight junction permeability

The REDIH experience: an emerging design to develop an effective training program for graduate students in reproductive science

Colla J MacDonald,1 Douglas Archibald,2 Jay M Baltz,3 Gerald M Kidder4 1Faculty of Education, 2Department of Family Medicine, University of Ottawa, Ottawa, ON, Canada; 3Ottawa Hospital Research Institute, Ottawa, ON, Canada; 4Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada Background: A training program in Reproduction, Early Development, and the Impact on Health (REDIH) was initiated in 2009 by researchers specializing in biomedical, clinical, population health, and ethics research from seven collaborating universities in Quebec and Ontario, and Health Canada. This paper reports the findings from the first three years of the 6-year program. Objectives: The objective of the REDIH program is to provide increased opportunities for excellent training in reproduction and early development for graduate students and fellows, in order to build research, clinical, regulatory, decision-making, and industry capacity in Canada. Methods: A mixed methods approach was used to evaluate the REDIH training program, so as to combine the strengths of both qualitative and quantitative studies. A total of four focus groups (two with mentors and two with trainees) were run during the June 2012 REDIH meeting. Surveys were administered directly after each training module. The W(e)Learn framework was used as a guide to design and evaluate the program and answer the research questions. Results: The data from the analysis of the focus group interviews, in corroboration with the survey data, suggested trainees enjoyed and benefited from the REDIH experience. Trainees provided several examples of new knowledge and skills they had acquired from REDIH sessions, regarding reproductive and early developmental biology, and health. A few trainees who had been in the program for over a year provided examples of knowledge and skills acquired during the REDIH session that they were using in their place of work. Next steps will include following up on REDIH graduates to see if the program has had any impact on trainees' employment opportunities and career development. Conclusion: Trainees and mentors concluded that the curricular design, which focuses on modules in 2-day learning sessions over a 6-year period, with opportunities for application in the workplace, enabled the sessions to be tailored to the outcomes of the formative evaluation. By sharing our experiences with REDIH, we hope that others can benefit from this unique emerging design, which focuses on the flexibility and receptivity of the mentors, and results in a program that lends itself to curriculum modification and tailoring as learners' needs are solicited and addressed. Keywords: graduate training, mentorship program, program evaluation, reproductive medicin