Prostate cancer and prostatic diseases, Feb 24, 2024
Sperm Chromatin Dispersion Test Detects Sperm DNA Fragmentation Mainly Associated with Unviable Spermatozoa and Underestimates the Values with Respect to TUNEL Assay
International journal of molecular sciences, Apr 19, 2024
Mammalian testicular spermatozoa are immotile, thus, to reach the oocyte, they need to acquire sw... more Mammalian testicular spermatozoa are immotile, thus, to reach the oocyte, they need to acquire swimming ability under the control of different factors acting during the sperm transit through the epididymis and the female genital tract. Although bicarbonate is known to physiologically increase motility by stimulating soluble adenylate cyclase (sAC) activity of mammalian spermatozoa, no extensive studies in human sperm have been performed yet to elucidate the additional molecular mechanisms involved. In this light, we investigated the effect of in vitro addition of bicarbonate to human spermatozoa on the main intracellular signaling pathways involved in regulation of motility, namely, intracellular cAMP production and protein tyrosine phosphorylation. Bicarbonate effects were compared with those of the phosphatidyl-inositol-3 kinase inhibitor, LY294002, previously demonstrated to be a pharmacological stimulus for sperm motility. Bicarbonate addition to spermatozoa results in a significant increase in sperm motility as well as in several hyperactivation parameters. This stimulatory effect of bicarbonate and LY294002 is mediated by an increase in cAMP production and tyrosine phosphorylation of the A kinase anchoring protein, AKAP3. The specificity of bicarbonate effects was confirmed by inhibition with 4,4-di-isothiocyanostilbene-2,2-disulfonic acid. We remark that, in human spermatozoa, bicarbonate acts primarily through activation of sAC to stimulate tyrosine phosphorylation of AKAP3 and sperm motility because both effects are blunted by the sAC inhibitor 2OH-estradiol. In conclusion, our data provide the first evidence that bicarbonate stimulates human sperm motility and hyperactivation through activation of sAC and tyrosine phosphorylation of AKAP3, finally leading to an increased recruitment of PKA to AKAP3.
Anabolic-androgenic steroids (AAS) represent a group of heterogeneous compounds, which include te... more Anabolic-androgenic steroids (AAS) represent a group of heterogeneous compounds, which include testosterone (T) and its derivate substances, largely used to enhance physical performance, sense of well-being and cosmetic appearance among athletes [1-4]. Some years after T isolation and synthesis in 1935 [5], Bøje [6] had already discussed the possible use of sex steroids in athletes. Alleged information suggests that the Ger
Biological meaning of ubiquitination and DNA fragmentation in human spermatozoa
PubMed, 2007
The ubiquitin-proteasome is an ubiquitous system mainly devoted to protein degradation. The prese... more The ubiquitin-proteasome is an ubiquitous system mainly devoted to protein degradation. The presence of ubiquitinated proteins in male gametes suggests a role for this system also in reproduction. Available evidence indicate that ubiquitin in spermatozoa may have a role in semen quality control, as ubiquitinated defective spermatozoa in the epididymis are subsequently phagocytosed by epididymal epithelial cells. Moreover, a role both in the regulation of mitochondrial inheritance in mammals (paternal mitochondria are eliminated and their ubiquitination appears to be important for this process) and in sperm-oocyte interaction at fertilization (which is inhibited by an inhibitor of proteasome) have been also suggested. We found that both morphologically normal and abnormal human spermatozoa in semen may be ubiquitinated and that the percentage of ubiquitinated sperm in the ejaculate positively correlates with normal morphology and motility, suggesting that sperm ubiquitination may have a positive role in sperm functions. It remains to be defined if and which patterns of ubiquitination of spermatozoa may distinguish between the different biological functions of this system. In an attempt to answer this question, we set up a method to detect simultaneously ubiquitination and DNA fragmentation by FACScan since the latter parameter is related to a poor quality of semen; in particular, abnormal morphology. We found that DNA fragmented human spermatozoa are also ubiquitinated. Studies are in progress to determine the correlation between the fraction of ubiquitinated-non DNA fragmented spermatozoa and parameters of semen analysis.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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Papers by Sara Marchiani