RESUMEN
DNA double-strand breaks (DSBs) are functionally linked to genomic instability in spermatocytes and to male infertility. The heavy metal cadmium (Cd) is known to induce DNA damage in spermatocytes by unknown mechanisms. Here, we showed that Cd ions impaired the canonical non-homologous end-joining (NHEJ) repair pathway, but not the homologous recombination (HR) repair pathway, through stimulation of Ser2056 and Thr2609 phosphorylation of DNA-PKcs at DSB sites. Hyper-phosphorylation of DNA-PKcs led to its premature dissociation from DNA ends and the Ku complex, preventing recruitment of processing enzymes and further ligation of DNA ends. Specifically, this cascade was initiated by the loss of PP5 phosphatase activity, which results from the dissociation of PP5 from its activating ions (Mn), that is antagonized by Cd ions through a competitive mechanism. In accordance, in a mouse model Cd-induced genomic instability and consequential male reproductive dysfunction were effectively reversed by a high dosage of Mn ions. Together, our findings corroborate a protein phosphorylation-mediated genomic instability pathway in spermatocytes that is triggered by exchange of heavy metal ions.
Asunto(s)
Cadmio , Inestabilidad Genómica , Infertilidad Masculina , Espermatocitos , Animales , Humanos , Masculino , Ratones , Cadmio/toxicidad , ADN/metabolismo , Reparación del ADN por Unión de Extremidades , Reparación del ADN , Inestabilidad Genómica/efectos de los fármacos , Infertilidad Masculina/genética , Infertilidad Masculina/metabolismo , Iones/metabolismo , Fosforilación , Reparación del ADN por Recombinación , Espermatocitos/efectos de los fármacosRESUMEN
PURPOSE: Vitamin D (VD) deficiency seems to be associated with the risk of recurrent spontaneous abortion (RSA). Vitamin D receptor (VDR) and cytochrome P450 family 2 subfamily R member 1 (CYP2R1) are two genes which are vital for VD metabolism and actions. However, whether single-nucleotide polymorphisms (SNPs) in these genes are correlated with the risk of RSA are poorly understood. Therefore, we aimed to characterize the relationships among VDR SNPs, CYP2R1 SNPs and RSA. METHODS: This case-control study enrolled 75 RSA patients and 83 controls. Serum VD and some cytokines were detected with LC-MS/MS and flow cytometry, respectively. Genotyping for three SNPs of CYP2R1 (rs10741657, rs10766197 and rs12794714) and five SNPs of VDR (rs7975232, rs1544410, rs2189480, rs2228570 and rs2239179) was done with polymerase chain reaction (PCR) and high-throughput sequencing. All the data were analyzed with appropriate methods and in different models. RESULTS: The results revealed a significant correlation between the AG genotype of CYP2R1 rs12794714 and VD levels (OR 0.686; 95% CI 0.49-0.96; p = 0.028). Besides, the AG and GG genotypes of CYP2R1 rs12794714 were markedly related to the risk of RSA (OR 52.394, 59.497; 95% CI 2.683-1023.265, 3.110-1138.367; p = 0.009, 0.007, respectively). CONCLUSION: Our results indicate that CYP2R1 rs12794714 might be a risk factor for RSA. Hence, early screening of pregnant women for CYP2R1 rs12794714 is necessary to warrant proactive counseling and treatment against RSA.
Asunto(s)
Aborto Habitual/genética , Colestanotriol 26-Monooxigenasa/genética , Familia 2 del Citocromo P450/genética , Receptores de Calcitriol/genética , Deficiencia de Vitamina D/genética , Vitamina D/sangre , Adulto , Estudios de Casos y Controles , Cromatografía Liquida , Femenino , Predisposición Genética a la Enfermedad , Genotipo , Humanos , Polimorfismo de Nucleótido Simple , Embarazo , ARN Mensajero/genética , Espectrometría de Masas en Tándem , Deficiencia de Vitamina D/sangreRESUMEN
OBJECTIVE: To analyze the numerical aberration of chromosome X, Y and 18 in the spermatozoa of asthenospermia patients by triple-color fluorescence in situ hybridization. METHODS: The experiment included 10 asthenospermia patients and 5 healthy men with normal semen quality as controls. Fluorescence in situ hybridization (FISH) and probes for chromosomes including X, Y and 18 were used to determine the frequency of the aneuploid of the chromosomes in spermatozoa. RESULTS: Of the 45,547 spermatozoa counted from the semen samples, the hybridization rate was 99.18%. The frequencies of the chromosome disomies including XX18, XY18, YY18, X1818 and Y1818 were (0.124 +/- -0.086)%, (0.360 +/- 0.380)%, (0.109 +/- 0.195)%, (0.342 +/- 0.746)% and (0.299 +/- 0.564)% in the case group and (0.014 +/- 0.019)%, (0.090 +/- 0.080)%, (0.030 +/- 0.031)%, (0.068 +/- 0.103)% and (0.075 +/- 0.083)% in the control. The sperm aneuploid rate was 9.25% in the former and 2.70% in the latter, with significant difference in between (P< 0.01). CONCLUSION: Asthenospermia patients have a higher aneuploid rate of sperm chromosome than normal fertile men. However, larger samples are yet to be studied to obtain more scientific evidence.