Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0154251 (lipid disorder)
 795 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The signaling pathways that characterize the process of capacitation of human spermatozoa are still largely unknown. Modifications in the lipid architecture of the sperm plasma membrane have been described in spermatozoa from different species, including translocation of phosphatidylserine (PS) from the inner to the outer leaflet and increased phospholipid disorder in the membrane. In human spermatozoa, however, results of PS exposure are controversial. In the present study, we used flow cytometry to investigate both membrane PS exposure by Annexin V (Ann V) binding and lipid disorder by merocyanine 540 (M540) staining, in swimup-selected live spermatozoa after incubation in conditions leading to capacitation. Our results indicate that neither probe is able to detect capacitation-related membrane modifications. Investigation of the nature of PS exposure and M540-positive live cells was then carried out. We found that M540 stains elements devoid of nuclei are present in seminal plasma. Live PS-exposing cells were mainly represented by damaged spermatozoa as revealed by the occurrence of a negative correlation between PS exposure and normal morphology and motility in unselected samples. The same cells were also positive for M540. These results demonstrate that Ann V and M540 binding in human sperm samples mainly detects cells with early membrane degeneration as well as dead cells, which is in agreement with findings obtained for somatic cells in which the two probes recognize cells with a damaged membrane due to the apoptotic process.
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PMID:AnnexinV binding and merocyanine staining fail to detect human sperm capacitation. 1529 13

Lipophilic fluorescent dye merocyanine 540 is believed to stain cell membranes with increasing affinity as the lipid components become more disordered and has been associated with changes in membrane fluidity. The aim of this study was to determine whether membrane lipid disorder is associated with capacitation of macaque spermatozoa. To induce capacitation, spermatozoa from 5 rhesus macaques were incubated at 37 degrees C (5% CO(2) in air) for 2 hours in a modified Biggers-Whitten-Whittingham medium containing 30 mg/mL bovine serum albumin and 36 mmol/L NaHCO(3). Caffeine (1 mmol/L) and dbcAMP (1.2 mmol/L) were added to the medium, and incubation was performed for an additional 30 minutes. Sperm motility was determined by computer-assisted sperm analysis, and membrane lipid order and sperm viability was determined by flow cytometry with merocyanine (2.7 micromol/L) and Yo-Pro-1 (25 nmol/L), respectively. Tyrosine phosphorylation of proteins in sperm tail was immunohistochemically examined by means of anti-phosphotyrosine (alpha-PY; clone 4G10). Capacitation resulted in a significant increase in the amplitude of lateral head displacement and beat cross frequency (P < .005) and a significant decrease in linearity and straightness in capacitated spermatozoa (P < .005), compared with control spermatozoa, which suggests the expression of hyperactivated motility. Animals in which capacitation was induced had a significant increase in the number of spermatozoa showing tyrosine phosphorylation of tail proteins (P < .0001) and a significant increase in the intensity of merocyanine fluorescence (P < .0001), compared with control animals. The observed decrease in membrane lipid order after capacitation was induced was not associated with surface exposure of phosphatidylserine, as determined by flow cytometry with annexin V-Alexa Fluor 488. Merocyanine may be a useful tool for investigating the role of the plasma membrane on capacitation and other cytotoxic events in macaque spermatozoa.
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PMID:Changes in membrane lipid order with capacitation in rhesus macaque (Macaca mulatta) spermatozoa. 1658 19