Phospholipase A 2 (PLA 2 ) activity has been shown to be involved in the sperm acrosome reaction (AR), but the molecular identity of PLA 2 isoforms has remained elusive. Here, we have tested the role of two intracellular (iPLA 2 ␤ and cytosolic PLA 2 ␣) and one secreted (group X) PLA 2 s in spontaneous and progesterone (P4)-induced AR by using a set of specific inhibitors and knock-out mice. iPLA 2 ␤ is critical for spontaneous AR, whereas both iPLA 2 ␤ and group X secreted PLA 2 are involved in P4-induced AR. Cytosolic PLA 2 ␣ is dispensable in both types of AR. P4-induced AR spreads over 30 min in the mouse, and kinetic analyses suggest the presence of different sperm subpopulations, using distinct PLA 2 pathways to achieve AR. At low P4 concentration (2 M), sperm undergoing early AR (0 -5 min post-P4) rely on iPLA 2 ␤, whereas sperm undergoing late AR (20 -30 min post-P4) rely on group X secreted PLA 2 . Moreover, the role of PLA 2 s in AR depends on P4 concentration, with the PLA 2 s being key actors at low physiological P4 concentrations (<2 M) but not at higher P4 concentrations (ϳ10 M).

BackgroundRobertsonian translocations (RobT) are common structural chromosome rearrangements where carriers display a majority of chromosomally balanced spermatozoa from alternate segregation mode. According to some monotony observed in the rates of balanced segregation, is sperm FISH analysis obsolete for RobT carriers?MethodsRetrospective cohort research study on 23 patients analyzed in our center from 2003 to 2017 and compared to the data of 187 patients in literature from 1983 to 2017.Robertsonian translocation carriers were divided in six groups according to the chromosomes involved in the translocation: 9 patients from our center and 107 from literature carrying 45,XY,der(13;14) karyotype, 3 and 35 patients respectively with 45,XY,der(14;21), 5 and 11 patients respectively with 45,XY,der(13;15), 4 and 7 patients respectively with 45,XY,der(14;15), 1 and 4 patients respectively with 45,XY,der(13;22),and 1 and 10 patients respectively with 45,XY,der(14;22).ResultsAlternate segregation mode is predominant in our group of Robertsonian translocation carriers with 73.45% ±8.05 of balanced spermatozoa (min 50.92%; max 89.99%). These results are compliant with the data from literature for all translocations types (p > 0.05) and are consistent among the different types of Robertsonian translocations (p > 0.05) except for der(13;15) that exhibit lower balanced spermatozoa rates (p < 0.05 versus der(13;14), der(14;21), (13;21) and der(15;22)). Normozoospermic patients also display a significantly (p < 0.01) higher rate of balanced sperm cells than patients with abnormal seminograms whatever the defect implied.ConclusionsAccording to the discrepancies observed between der(13;15) and all the other Rob T carriers, the differences observed among patients presenting normal and abnormal sperm parameters and the input in genetical counselling, sperm FISH does not seem obsolete for these patients. Moreover, it seems important to collect more data for rare RobT.