Differential expression of the orphan G-protein coupled receptor GPR55 in human spermatozoa

Abstract

ObjectiveThe endocannabinoid anandamide (N-arachidonylethanolamide, AEA), reduces human sperm motility and viability by interacting with two G protein-coupled cannabinoid receptors CB1 and CB2. Recent evidence suggests that palmitoylethanolamide signalling through another G-protein coupled receptor GPR55 increases sperm motility and viability. This study was undertaken to explore the presence and differential expression of GPR55 receptor in human spermatozoa.DesignProspective laboratory based clinical study.Materials and MethodsSemen samples were obtained by masturbation from 52 patients (normozoospermia, n = 19 asthenozoospermia, n = 9 teratozoospermia, n = 11 and oligoasthenoteratozoospermia, n = 13). Spermatozoa were separated from seminal plasma by centrifugation and total RNA isolated from spermatozoa. 500ng of total RNA was reverse transcribed to cDNA and GPR55 mRNA were measured by quantitative reverse transcription-polymerase chain reaction using specific primers and SYBR green detection system.ResultsmRNA transcripts were quantified in all 52 samples indicating the presence of GPR55 receptors in human spermatozoa. The GPR55 mRNA transcript levels were significantly lower in spermatozoa from men with astenozoospermia (P<0.001) compared with the normozoospermic controls. There was also a trend towards attenuation of GPR55 mRNA in those with teratozoospermia and oligoasthenoteratozoospermia, although this did not reach statistical significance.ConclusionOur results show that the orphan G-protein coupled receptor GPR55 is expressed in human spermatozoa and the expression is altered in men with abnormal sperm functions suggesting that this signalling pathway may be useful biomarkers for predicting male infertility. ObjectiveThe endocannabinoid anandamide (N-arachidonylethanolamide, AEA), reduces human sperm motility and viability by interacting with two G protein-coupled cannabinoid receptors CB1 and CB2. Recent evidence suggests that palmitoylethanolamide signalling through another G-protein coupled receptor GPR55 increases sperm motility and viability. This study was undertaken to explore the presence and differential expression of GPR55 receptor in human spermatozoa. The endocannabinoid anandamide (N-arachidonylethanolamide, AEA), reduces human sperm motility and viability by interacting with two G protein-coupled cannabinoid receptors CB1 and CB2. Recent evidence suggests that palmitoylethanolamide signalling through another G-protein coupled receptor GPR55 increases sperm motility and viability. This study was undertaken to explore the presence and differential expression of GPR55 receptor in human spermatozoa. DesignProspective laboratory based clinical study. Prospective laboratory based clinical study. Materials and MethodsSemen samples were obtained by masturbation from 52 patients (normozoospermia, n = 19 asthenozoospermia, n = 9 teratozoospermia, n = 11 and oligoasthenoteratozoospermia, n = 13). Spermatozoa were separated from seminal plasma by centrifugation and total RNA isolated from spermatozoa. 500ng of total RNA was reverse transcribed to cDNA and GPR55 mRNA were measured by quantitative reverse transcription-polymerase chain reaction using specific primers and SYBR green detection system. Semen samples were obtained by masturbation from 52 patients (normozoospermia, n = 19 asthenozoospermia, n = 9 teratozoospermia, n = 11 and oligoasthenoteratozoospermia, n = 13). Spermatozoa were separated from seminal plasma by centrifugation and total RNA isolated from spermatozoa. 500ng of total RNA was reverse transcribed to cDNA and GPR55 mRNA were measured by quantitative reverse transcription-polymerase chain reaction using specific primers and SYBR green detection system. ResultsmRNA transcripts were quantified in all 52 samples indicating the presence of GPR55 receptors in human spermatozoa. The GPR55 mRNA transcript levels were significantly lower in spermatozoa from men with astenozoospermia (P<0.001) compared with the normozoospermic controls. There was also a trend towards attenuation of GPR55 mRNA in those with teratozoospermia and oligoasthenoteratozoospermia, although this did not reach statistical significance. mRNA transcripts were quantified in all 52 samples indicating the presence of GPR55 receptors in human spermatozoa. The GPR55 mRNA transcript levels were significantly lower in spermatozoa from men with astenozoospermia (P<0.001) compared with the normozoospermic controls. There was also a trend towards attenuation of GPR55 mRNA in those with teratozoospermia and oligoasthenoteratozoospermia, although this did not reach statistical significance. ConclusionOur results show that the orphan G-protein coupled receptor GPR55 is expressed in human spermatozoa and the expression is altered in men with abnormal sperm functions suggesting that this signalling pathway may be useful biomarkers for predicting male infertility. Our results show that the orphan G-protein coupled receptor GPR55 is expressed in human spermatozoa and the expression is altered in men with abnormal sperm functions suggesting that this signalling pathway may be useful biomarkers for predicting male infertility.