Epigenetic variation at the SLC6A4 gene promoter in mother-child pairs with major depressive disorder.

BACKGROUND: Genetic and epigenetic variations of the serotonin transporter gene (SLC6A4) have been related to the etiology of depression. The 5-HTTLPR polymorphism at the SLC6A4 promoter region has two variants, a short allele (S) and a long allele (L), in which the S allele results in lower gene transcription and has been associated with depression. The short S-allele of 5-HTTLPR polymorphism of this gene has been associated with depression. In addition to molecular mechanisms, exposure to early life risk factors such as maternal depression seems to affect the development of depression in postnatal life. The present study investigated the association of 5-HTTLPR polymorphism and CpG DNA methylation (5mC) levels of an AluJb repeat element at the SLC6A4 promoter region in mother-child pairs exposed to maternal depression. METHODS: We analyzed DNA samples from 60 subjects (30 mother-child pairs) split into three groups, with and without major depression disorder (DSM-IV) among children and mothers. The genotyping of 5-HTTLPR polymorphism and quantification of 5mC levels was performed by qualitative PCR and methylation-sensitive restriction enzyme digestion, and real-time quantitative PCR (MSRED-qPCR), respectively. RESULTS: The sample analyzed presented a higher frequency of S allele of 5-HTTLPR (67.5%). Despite the high frequency of this allele, we did not find statistically significant differences between individuals carrying at least one S allele between the depression and healthy control subjects, or among the mother-child pair groups with different patterns of occurrence of depression. In the group where the mother and child were both diagnosed with depression, we found a statistically significant decrease of the 5mC level at the SLC6A4 promoter region. LIMITATIONS: The limitations are the relatively small sample size and lack of gene expression data available for comparison with methylation data. CONCLUSION: In this study, we demonstrated a repeat element specific 5mC level reduction in mother-child pairs, concordant for the diagnosis of depression.

l-arginine alters the proteome of frozen-thawed bovine sperm during in vitro capacitation.

The aim of this work was to evaluate the proteomic changes that occurred in the frozen-thawed bovine spermatozoa after the addition of l-arginine (L-arg) during in vitro sperm capacitation. Aspects related to the sperm capacitation pattern like membrane integrity, mitochondrial activity, sperm motility and vigor, and the sperm proteome were determined. These were respectively assessed by chlortetracycline staining, H342/PI, JC-1, light microscopy, and the proteomic abundance by nUPLC-MS/MS analysis. Frozen-thawed sperm from three Nellore bulls were capacitated in vitro for 3 h in sp-TALP medium supplemented with 20 µg/mL heparin (Control) or with 20 µg/mL heparin plus 1 mM L-arg (L-arg group). Data were subjected to analysis of variance and means compared by SNK test at 5% probability. When compared to Control, the percentage of sperm motility was higher in the L-arg group (P < 0.05). For test data after 3 h of incubation, sperm capacitated with L-arg showed higher membrane integrity and mitochondrial potential when compared to Control (P < 0.05). Moreover, we observed an increase in the percentage of capacitated sperm pattern (P < 0.05). Protein abundance analysis identified 367 proteins. Forty proteins were differentially abundant between Control and L-arg group (P < 0.05), of which 11 were up-regulated, and 29 were down-regulated in L-arg group. In addition, we observed that one protein was uniquely abundant in the L-arg group. Our findings indicate that the addition of L-arg to the culture medium presented a differential protein abundance pattern and increased the bovine frozen-thawed sperm quality and the percentage of capacitated sperm. The proteomic changes observed may be linked to the molecular mechanisms involved in the action of L-arg on the in vitro sperm capacitation of cattle.

Association between IGF2 and CYP21 gene polymorphisms and characteristics of economic interest in Nellore cattle.

We analyzed two single nucleotide polymorphisms (SNPs) of the IGF2 and CYP21 genes in Nellore cattle participating in the Brazilian Animal Breeding Program. The SNPs were found in exon 6 of the IGF2 (insulin-like growth factor 2) gene (RFLP/MboII) as well as in the promoter region of the CYP21 (steroid 21-hydroxylase) gene (RFLP/HpaII) of these animals. The TC heterozygotes were significantly more frequent than CC and TT homozygotes in the RFLP/MboII polymorphism. The T allele was significantly more frequent than the C allele in RFLP/HpaII polymorphism. This population was found to be in Hardy-Weinberg equilibrium for these SNPs. Association of these polymorphisms with expected progeny differences of reproductive and productive traits was investigated, but proved to be significant only for DP550 (expected progeny differenced for weight at 365 days - IGF2 - RFLP/MboII) and DP450 (expected progeny differenced for weight at 450 days - CYP21 - RFLP/HpaII). This is the first study on the occurrence of these two polymorphisms in this Zebu breed of cattle. A total of 147 Nellore animals participating in the Breeding Program of the Nellore Breed (PMGRN) under the management of the National Association of Breeders and Researchers (ANCP) in the city of Ribeirão Preto were analyzed.

Identification of a DNA methylation point in the promoter region of the bovine CYP21 gene.

The CYP21 (steroid 21-hydroxylase) gene is involved in the synthesis of steroid hormones. Bov-A2 is a retroposon that is common in ruminant genomes. The promoter region of bovine CYP21 contains a short interspersed nucleotide element of Bov-A2, which overlaps a putative Sp1 binding site. We looked for RFLP/HpaII polymorphism in the Bov-A2 element in bovine Zebu breeds by PCR-RFLP, and examined whether polymorphism in this element is associated with methylation. Among DNA samples from 135 Brazilian Zebu breed cattle, we identified an RFLP/HpaII polymorphism (T/C), which, based on a restriction methylation-sensitive assay employing HpaII and isoschizomer MspI enzymes (methylation-sensitive and -non-sensitive enzymes, respectively), appears to be a DNA methylation point. This is the first report of this polymorphism and on DNA methylation in the bovine CYP21 promoter region in Brazilian Zebu cattle.

Bovine fetal DNA in the maternal circulation: Applications and implications.

OBJECTIVE: The main aim of the present study was to detect bovine fetal DNA in the maternal circulation, a relatively unexplored subject in the literature. STUDY DESIGN: DNA was extracted from blood of 84 primipara cows (Bos indicus) at different gestational ages (30-270 days) and from 100 adult animals (50 males and 50 non-pregnant cows). The samples were analyzed using PCR with primers for TSPY gene. RESULTS: Molecular results matched the fetal phenotypic gender in all 47 male and 37 female fetuses, including early pregnancy, and in control animals. CONCLUSIONS: These results evidence a bovine transplacental fetal DNA passage.

Investigation of IGF2/ApaI and H19/RsaI polymorphisms in patients with cutaneous melanoma.

OBJECTIVE: The etiology of cutaneous melanoma is complex, involving both heterogeneous genetic and environmental components. The aim of our study was to verify if single polymorphic sites within IGF2 and H19 genes and their consequent haplotypes influence risk and/or prognosis of familial melanoma. DESIGN: Twenty one patients with clinical criteria of hereditary melanoma (early onset, presence of multiple primary melanoma, and/or one or more affected first- or second-degree relatives) and previously screened for CDKN2A mutations were genotyped by IGF2/ApaI and H19/RsaI PCR-RFLPs. Data were compared between patients and a control group (100 healthy young individuals) using Chi-square and Fisher's exact tests. We also investigated if these polymorphic sites could be microRNAs potential targets, using RegRNA software. RESULTS: Although the IGF2 and H19 genotypes/haplotypes were not significantly associated with melanoma, two of the most severe cases (very early onset or multiple melanomas) showed to be heterozygous for both genes. We found an overlap between IGF2/ApaI and miR-615-5p, and between H19/RsaI and miR-574-3p. CONCLUSIONS: Some studies have shown H19, and IGF2 genes (or related genes or protein, for example, IGF2R and IMP-3) differential expression in melanoma. However, no study has attempted to examine markers across this cluster in relation to melanoma until now. Since the base change may impair the pairing of microRNA and its binding site, our results suggest a new window for future studies of IGF2 and H19 genetic variability and posttranscriptional regulation. Due to the importance and based on the present results, we suggest that the genotype/haplotype analysis of IGF2 and H19 polymorphisms should be better investigated in large populations with cutaneous melanoma, attempting to tie the association with progression of the disease.

IGF2/Mboll polymorphism in Gir and Nelore cattle.

The imprinted gene insulin-like growth factor 2 (IGF2) carries out important functions in the development of placental mammals, during the embryonic and fetal stages and is located on bovine chromosome 29. The main aim of this study was to verify the occurrence of a polymorphism (C/T transversion) in exon 6 of the IGF2 gene in Gir and Nelore cattle, Zebu breeds of great economic importance in Brazil for dairy and beef production, respectively. A 193 bp fragment of bovine IGF2 exon 6 was amplified by PCR with specific primers for this region and digested with Mboll enzyme to analyze the polymorphic segment. In a total of 39 Gir animals (29 females and 10 males), the estimated frequencies of the C and T alleles were 0.42 and 0.58, respectively. The genotypic frequencies were 0.10 for CC, 0.26 for TT and 0.64 for CT. For 28 Nelore animals (17 females and 11 males), the estimated frequencies of the C and T alleles were 0.43 and 0.57, respectively. The genotypic frequencies were 0.18 for CC, 0.32 for TT, and 0.50 for CT. This is the first report of the occurrence of this polymorphism in these breeds. The polymorphic site can be a regulatory motif with functional significance to gene regulation of the IGF2 gene. This polymorphism could be used to investigate the allele-specific expression of the IGF2 gene, its epigenetic status, and its role in developmental, growth and reproductive traits.