Proteomic analysis reveals dysregulated cell signaling in ejaculated spermatozoa from infertile men / 亚洲男科学杂志(英文版)

Dysfunctional sperm maturation is the primary reason for the poor sperm motility and morphology in infertile men. Spermatozoa from infertile men were fractioned on three-layer density gradient (80%, 60%, and 40%). Fraction 1 (F1) refers to the least mature stage having the lowest density, whereas the fraction 4 (F4) includes the most dense and morphologically mature motile spermatozoa. Fraction 2 (F2) and fraction 3 (F3) represent the intermediate stages. Proteins were extracted and separated by 1-dimensional gel. Bands were digested with trypsin and analyzed on a LTQ-Orbitrap Elite hybrid mass spectrometer system. Functional annotations of proteins were obtained using bioinformatics tools and pathway databases. A total of 1585 proteins were detected in the four fractions of spermatozoa. A dysregulated protein turnover and protein folding may lead to accumulation of defective proteins or proteins that otherwise would have been eliminated during the process of maturation, resulting in the impairment of sperm function. Aberrant chaperone expression may be a major contributing factor to the defective sperm function. Androgen receptor was predicted as a transcription regulator in one of the networks and the affected pathways were chaperone-mediated stress response, proteosomal pathway, and sperm function. The downregulation of key pathways and proteins which compromises the fertilizing potential of spermatozoa may provide insight into the mechanisms that lead to male infertility.

Proteomic analysis of mature and immature ejaculated spermatozoa from fertile men / 亚洲男科学杂志(英文版)

Dysfunctional spermatozoa maturation is the main reason for the decrease in sperm motility and morphology in infertile men. Ejaculated spermatozoa from healthy fertile men were separated into four fractions using three-layer density gradient. Proteins were extracted and bands were digested on a LTQ-Orbitrap Elite hybrid mass spectrometer system. Functional annotations of proteins were obtained using bioinformatics tools and pathway databases. Western blotting was performed to verify the expression levels of the proteins of interest. 1469 proteins were identified in four fractions of spermatozoa. The number of detected proteins decreased according to the maturation level of spermatozoa. During spermatozoa maturation, proteins involved in gamete generation, cell motility, energy metabolism and oxidative phosphorylation processes showed increasing expression levels and those involved in protein biosynthesis, protein transport, protein ubiquitination, and response to oxidative stress processes showed decreasing expression levels. We validated four proteins (HSP 70 1A, clusterin, tektin 2 and tektin 3) by Western blotting. The study shows protein markers that may provide insight into the ejaculated spermatozoa proteins in different stages of sperm maturation that may be altered or modified in infertile men.

Enlightenment from the reproductive medicine center summer internship program in Cleve-land Clinic / 中华医学教育探索杂志

The Summer internship program has been successfully carried out in the Center for Reproductive Medicine in Cleveland Clinic for six years (from 2008 to 2013). This program includes lecture, essay writing and experimental research. Until this year, this program has trained 109 stu-dents from United States and all over the world. The students have published 78 articles in SCI jour-nals. This program has a good reputation in the international reproductive medicine education area. The program provides students strong backgrounds of an internship experience, which is helpful to the students when they apply for high level medical school and residency qualification. At present, the students in China have a strong and urgent demand for the similar programs. Some high level medical schools of our country have the personnel and equipment base to carry out these programs. Medical schools can carry out similar programs in our country by using the organization and implementation experiences of Cleveland Clinic to provide high-level Chinese medical students with practice experi-ence out of the course education.