XRCC1 399 Arg-related genotype and allele, but not XRCC1 His107Arg, XRCC1 Trp194Arg, KCNQ2, AT1R, and hOGG1 polymorphisms, are associated with higher susceptibility of endometriosis

XRCC1 Polymorphisms p.Arg194Trp, p.Arg280His, and p.Arg399Gln, Polycyclic Aromatic Hydrocarbons, and Infertility: A Case-Control and In Silico Study

XRCC1 is involved in repair of single-strand breaks generated by mutagenic exposure. Polymorphisms within XRCC1 affect its ability to efficiently repair DNA damage. Polycyclic aromatic hydrocarbons or PAHs are genotoxic compounds which form bulky DNA adducts that are linked with infertility. Few reports suggest combined role of XRCC1 polymorphisms and PAHs in infertility. Present study investigates association of three XRCC1 polymorphisms (p.Arg194Trp, p.Arg280His, p.Arg399Gln) with male and female infertility in a North-West Indian population using case-control approach. Additionally, in silico approach has been used to predict whether XRCC1 polymorphisms effect interaction of XRCC1 with different PAHs. For case-control study, XRCC1 polymorphisms were screened in peripheral blood samples of age- and gender-matched 201 infertile cases (♂-100, ♀-101) and 201 fertile controls (♂-100, ♀-101) using PCR-RFLP method. For in silico study, AutoDock v4.2.6 was used for molecular docking of B[a]P, BPDE-I, ( ±)-anti-BPDE, DB[a,l]P, 1-N, 2-N, 1-OHP, 2-OHF with XRCC1 and assess effect of XRCC1 polymorphisms on their interaction. In case-control study, statistical analysis showed association of XRCC1 p.Arg280His GA genotype (p = 0.027), A allele (p = 0.019) with reduced risk of male infertility. XRCC1 p.Arg399Gln AA genotype (p = 0.021), A allele (p = 0.014) were associated with reduced risk for female primary infertility. XRCC1 p.Arg194Trp T allele was associated with increased risk for female infertility (p = 0.035). In silico analysis showed XRCC1-PAH interaction with non-significant effect of XRCC1 polymorphisms on predicted binding. Therefore, present study concludes that XRCC1 polymorphism-modified risk for male and female infertility in North-West Indians without significant effect on predicted XRCC1-PAH interactions. This is the first report on XRCC1 in female infertility.

Physiological and pathological roles of Ang II and Ang- (1-7) in the female reproductive system

The local Renin-Angiotensin System (RAS) has been demonstrated to exist in a wide range of tissues and organs, In the female reproductive system, it is mainly found in the ovary, uterus and placenta. The RAS system is made up of a series of active substances and enzymes, in addition to the circulating endocrine renin-angiotensin system. The active peptides Angiotensin II (Ang II) and Angiotensin (1-7) (Ang-(1-7)), in particular, appear to have distinct activities in the local RAS system, which also controls blood pressure and electrolytes. Therefore, in addition to these features, angiotensin and its receptors in the reproductive system seemingly get involved in reproductive processes, such as follicle growth and development, as well as physiological functions of the placenta and uterus. In addition, changes in local RAS components may induce reproductive diseases as well as pathological states such as cancer. In most tissues, Ang II and Ang- (1-7) seem to maintain antagonistic effects, but this conclusion is not always true in the reproductive system, where they play similar functions in some physiological and pathological roles. This review investigated how Ang II, Ang- (1-7) and their receptors were expressed, localized, and active in the female reproductive system. This review also summarized their effects on follicle development, uterine and placental physiological functions. The changes of local RAS components in a series of reproductive system diseases including infertility related diseases and cancer and their influence on the occurrence and development of diseases were elucidated. This article reviews the physiological and pathological roles of Ang II and Ang- (1-7) in female reproductive system,a very intricate system of tissue factors that operate as agonists and antagonists was found. Besides, the development of novel therapeutic strategies targeting components of this system may be a research direction in future.

Endometrial DNA damage response is modulated in endometriosis

STUDY QUESTION

Is the DNA damage response (DDR) dysregulated in the eutopic endometrium of women with endometriosis?

SUMMARY ANSWER

Endometrial expression of genes involved in DDR is modulated in women with endometriosis, compared to those without the disease.

WHAT IS KNOWN ALREADY

Ectopic endometriotic lesions are reported to harbour somatic mutations, thereby hinting at dysregulation of DDR and DNA repair pathways. However, it remains inconclusive whether the eutopic endometrium also manifests dysregulated DDR in endometriosis.

STUDY DESIGN, SIZE, DURATION

For this case-control study conducted between 2015 and 2019, eutopic endometrial (E) samples (EE- from women with endometriosis, CE- from women without endometriosis) were collected in either mid-proliferative (EE-MP, n = 23; CE-MP, n = 17) or mid-secretory (EE-MS, n = 17; CE-MS, n = 9) phases of the menstrual cycle. This study compares: (i) DNA damage marker localization, (ii) expression of DDR genes and (iii) expression of DNA repair genes in eutopic endometrial samples from women with and without endometriosis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study included (i) 40 women (aged 31.9 ± 0.81 years) with endometriosis and (ii) 26 control women (aged 31.4 ± 1.02 years) without endometriosis. Eutopic endometrial samples from the two groups were divided into different parts for histological analysis, immunohistochemistry, RNA extraction, protein extraction and comet assays. Eighty-four genes of relevance in the DNA damage signalling pathway were evaluated for their expression in eutopic endometrial samples, using RT2 Profiler PCR arrays. Validations of the expression of two GADD (Growth Arrest DNA Damage Inducible) proteins - GADD45A and GADD45G were carried out by immunoblotting. DNA damage was assessed by immunohistochemical localization of γ-H2AFX (a phosphorylated variant of histone H2AX) and 8-OHdG (8-hydroxy-2'-deoxyguanosine). RNA sequencing data from mid-proliferative (EE-MP, n = 4; CE-MP, n = 3) and mid-secretory phase (EE-MS and CE-MS, n = 4 each) endometrial samples were scanned to compare the expression status of all the genes implicated in human DNA repair. PCNA (Proliferating Cell Nuclear Antigen) expression was determined to assess endometrial proliferation. Residual DNA damage in primary endometrial cells was checked by comet assays. Public datasets were also scanned for the expression of DDR and DNA repair genes as our RNASeq data were limited by small sample size. All the comparisons were made between phase-matched endometrial samples from women with and without endometriosis.

MAIN RESULTS AND THE ROLE OF CHANCE

Endometrial expression of DDR genes and intensity of immunolocalized γ-H2AFX were significantly (P < 0.05) higher in EE, compared to CE samples. DDR proteins, especially those belonging to the GADD family, were found to be differentially abundant in EE, as compared to CE. These patterns were evident in both mid-proliferative and mid-secretory phases. Intriguingly, higher DDR was associated with increased cell proliferation in EE-MP, compared to CE-MP. Furthermore, among the differentially expressed transcripts (DETs) encoded by DNA repair genes, the majority showed up-regulation in EE-MP, compared to CE-MP. Interestingly, CE-MP and EE-MP had a comparable percentage (P > 0.05) of cells with residual DNA damage. However, unlike the mid-proliferative phase data, many DETs encoded by DNA repair genes were down-regulated in EE-MS, compared to CE-MS. An analysis of the phase-matched control and endometriosis samples included in the GSE51981 dataset available in the Gene Expression Omnibus database also revealed significant (P < 0.05) alterations in the expression of DDR and DNA repair genes in EE, compared to CE.

LARGE-SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The study was conducted on a limited number of endometrial samples. Also, the study does not reveal the causes underlying dysregulated DDR in the eutopic endometrium of women with endometriosis.

WIDER IMPLICATIONS OF THE FINDINGS

Alterations in the expression of DDR and DNA repair genes indirectly suggest that eutopic endometrium, as compared to its healthy counterpart, encounters DNA damage-inducing stimuli, either of higher strength or for longer duration in endometriosis. It will be worthwhile to identify the nature of such stimuli and also explore the role of higher genomic insults and dysregulated DDR/DNA repair in the origin and/or progression of endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

The study was supported by the Department of Biotechnology and Indian Council of Medical Research, Government of India. No conflict of interest is declared.

Genetic variants in the nucleotide excision repair genes are associated with the risk of developing endometriosis

Endometriosis is a major health issue among women of reproductive age. However, its etiology has not yet been completely understood. We investigated 10 single nucleotide polymorphisms from six novel nucleotide excision repair genes and the susceptibility to endometriosis. A total of 153 patients with endometriosis were recruited during 2000-2010 from central Taiwan. Pathological confirmation was necessary for all patients, and exclusion criteria included the presence of leiomyoma, adenomyosis, or cancer of the uterine, cervix, or ovary and a prescription of hormone therapy. Furthermore, a total of 636 age-matched individuals without endometriosis were recruited during the same time period from central Taiwan. The polymerase chain reaction coupled with restriction fragment length polymorphism methodology was applied for genotyping. The multivariate logistic regression analysis showed that subjects carrying the ERCC1 rs11615 TT (OR = 2.04, 95% CI = 1.36-3.41), ERCC2 rs1799793 AA (OR = 1.86, 95% CI = 1.14-3.11), and ERCC6 rs2228528 AA genotypes (OR = 1.79, 95% CI = 1.13-2.83) exhibited significantly increased risks of developing endometriosis compared with their counterparts carrying the wild-type genotypes. This study suggests that certain single nucleotide polymorphisms of nucleotide excision repair genes excision repair cross-complementation group 1 (ERCC1, ERCC2, and ERCC6) predispose women to the development of endometriosis.

Polymorphisms and endometriosis: a systematic review and meta-analyses

BACKGROUND

Endometriosis is an estrogen-dependent gynecological disorder that affects at least 10% of women of reproductive age. It may lead to infertility and non-specific symptoms such as chronic pelvic pain. Endometriosis screening and diagnosis are difficult and time-consuming. Late diagnosis (with a delay ranging from 3.3 to 10.7 years) is a major problem and may contribute to disease progression and a worse response to treatment once initiated. Efficient screening tests might reduce this diagnostic delay. As endometriosis is presumed to be a complex disease with several genetic and non-genetic pathogenic factors, many researchers have sought to identify polymorphisms that predispose to this condition.

OBJECTIVE AND RATIONALE

We performed a systematic review and meta-analysis of the most regularly reported polymorphisms in order to identify those that might predispose to endometriosis and might thus be of value in screening.

SEARCH METHODS

The MEDLINE database was searched for English-language publications on DNA polymorphisms in endometriosis, with no date restriction. The PubTator text mining tool was used to extract gene names from the selected publications' abstracts. We only selected polymorphisms reported by at least three studies, having applied strict inclusion and exclusion criteria to their control populations. No stratification based on ethnicity was performed. All steps were carried out according to PRISMA guidelines.

OUTCOMES

The initial selection of 395 publications cited 242 different genes. Sixty-two genes (corresponding to 265 different polymorphisms) were cited at least in three publications. After the application of our other selection criteria (an original case-control study of endometriosis, a reported association between endometriosis and at least one polymorphism, data on women of reproductive age and a diagnosis of endometriosis in the cases established by surgery and/or MRI and confirmed by histology), 28 polymorphisms were eligible for meta-analysis. Only five of the 28 polymorphisms were found to be significantly associated with endometriosis: interferon gamma (IFNG) (CA) repeat, glutathione S-transferase mu 1 (GSTM1) null genotype, glutathione S-transferase pi 1 (GSTP1) rs1695 and wingless-type MMTV integration site family member 4 (WNT4) rs16826658 and rs2235529. Six others showed a significant trend towards an association: progesterone receptor (PGR) PROGINS, interCellular adhesion molecule 1 (ICAM1) rs1799969, aryl-hydrocarbon receptor repressor (AHRR) rs2292596, cytochrome family 17 subfamily A polypeptide 1 (CYP17A1) rs743572, CYP2C19 rs4244285 and peroxisome proliferator-activated receptor gamma (PPARG) rs1801282), and 12 showed a significant trend towards the lack of an association: tumor necrosis factor (TNF) rs1799964, interleukin 6 (IL6) rs1800796, transforming growth factor beta 1 (TGFB1) rs1800469, estrogen receptor 1 (ESR1) rs2234693, PGR rs10895068, FSH receptor (FSHR) rs6166, ICAM1 rs5498, CYP1A1 rs4646903, CYP19A1 rs10046, tumor protein 53 (TP53) rs1042522, X-ray repair complementing defective repair in Chinese hamster cells 1 (XRCC1) rs25487 and serpin peptidase inhibitor clade E member 1 (SERPINE1) rs1799889; however, for the 18 polymorphisms identified in the latter two groups, further studies of the potential association with the endometriosis risk are needed. The remaining five of the 28 polymorphisms were not associated with endometriosis: glutathione S-transferase theta 1 (GSTT1) null genotype, vascular endothelial growth factor alpha (VEGFA) rs699947, rs833061, rs2010963 and rs3025039.

WIDER IMPLICATIONS

By carefully taking account of how the control populations were defined, we identified polymorphisms that might be candidates for use in endometriosis screening and polymorphisms not associated with endometriosis. This might constitute the first step towards identifying polymorphism combinations that predispose to endometriosis (IFNG (CA) repeat, GSTM1 null genotype, GSTP1 rs1695, WNT4 rs16826658 and WNT4 rs2235529) in a large cohort of patients with well-defined inclusion criteria. In turn, these results might improve the diagnosis of endometriosis in primary care. Lastly, our present findings may enable a better understanding of endometriosis and improve the management of patients with this disease.

Involvement of angiotensin II receptor type 1/NF-κB signaling in the development of endometriosis

Endometriosis (EM) is a common disease in women; however, the signaling pathways and related genes underlying the mechanisms of EM remain unclear. The present study aimed to investigate the role of angiotensin II receptor type 1 (AGTR1) in the pathogenesis of EM. Human EM tissues were collected, and the expression levels of AGTR1 and NF-κB in the tissues were analyzed using immunochemistry and western blotting, while the estrogen levels in the EM tissues were determined by ELISA. In vitro human endometrial stromal cells were used to investigate the expression levels of AGTR1 following exposure to estrogen; the interaction between AGTR1 and NF-κB was determined using reverse transcription-quantitative PCR and western blotting; and the effects of AGTR1 on cell proliferation, as well as the apoptotic and migratory abilities of the cells were evaluated using WST-1 assays, wound healing assays and flow cytometry, respectively. It was observed that both the expression levels of AGTR1 and the activity of NF-κB were increased in human EM tissues and stromal cells, and this activation of AGTR1 subsequently increased the activity of NF-κB. Moreover, estrogen was found to regulate the expression levels of AGTR1 in stromal cells. The activation of AGTR1 was demonstrated to promote cell proliferation and migration, in addition to preventing cells from undergoing apoptosis. In conclusion, the present study suggested that the increased activity of the AGTR1-NF-κB axis following the decreased exposure to estrogen may be important for the pathogenesis of EM. In addition, AGTR1 may be a potential therapeutic target for the treatment of EM.

Analysis of key candidate genes and pathways of endometriosis pathophysiology by a genomics-bioinformatics approach

Endometriosis is a common disease in women, but the signaling pathways and driven genes involved remain unclear. This study integrated four datasets to elucidate potential key candidate genes and pathways in endometriosis. Four expression profile datasets including 29 endometriosis lesions and 37 normal tissues were integrated and analyzed. Differentially expressed genes (DEGs) were sorted, and the gene ontology, pathway enrichment, and protein-protein interaction network of candidate genes were then analyzed. A total of 94 shared DEGs were identified from the four datasets. The DEGs were clustered based on functions and signaling pathways through the analysis of significant enrichment. Among the DEG protein-protein interaction network complex, 87 nodes/DEGs were identified. Furthermore, 18 central node genes were identified, and most of the corresponding genes were involved in the angiotensin system, smooth muscle contraction, cell junction organization, and lipoxin pathways. Through integrated bioinformatic analysis, we identified candidate genes and pathways in endometriosis, which could improve our understanding of endometriosis.

Protein-protein interaction analysis to identify biomarker networks for endometriosis

The identification of biomarkers and their interaction network involved in the processes of endometriosis is a critical step in understanding the underlying mechanisms of the disease. The aim of the present study was to construct biomarker networks of endometriosis that integrated human protein-protein interactions and known disease-causing genes. Endometriosis-associated genes were extracted from Genotator and DisGeNet and biomarker network and pathway analyses were constructed using atBioNet. Of 100 input genes, 96 were strongly mapped to six major modules. The majority of the pathways in the first module were associated with the proliferation of cancer cells, the enriched pathways in module B were associated with the immune system and infectious diseases, module C included pathways related to immune and metastasis, the enriched pathways in module D were associated with inflammatory processes, and the majority of the pathways in module E were related to replication and repair. The present approach identified known and potential biomarkers in endometriosis. The identified biomarker networks are highly enriched in biological pathways associated with endometriosis, which may provide further insight into the molecular mechanisms underlying endometriosis.

DNA repair gene XRCC1 and XRCC4 variations and risk of endometriosis: an association study

BACKGROUND

Endometriosis is a polygenic and multifactorial disease. DNA damage plays a major role in mutagenesis, carcinogenesis and aging and is usually repaired by the action of several DNA repair enzymes. We investigated the association of the common variations of the DNA repair genes XRCC1 and XRCC4 with susceptibility to endometriosis in an Iranian population.

METHODS

In total, 160 patients with endometriosis (stages I-IV) and 174 healthy women were included in this case-control study. Genotyping of XRCC1 codon 399 as well as of XRCC4 -1394T/G, codon 247 and intron 3 insertion/deletion variations was performed using restriction fragment length polymorphism analysis of PCR-amplified fragments.

RESULTS

The XRCC4 -1394TG genotype frequency was significantly lower (p = 0.005) in the patients (9.4%) than in the controls (21.1%). The frequency of the -1394G allele was significantly lower (p < 0.0001) in the patients (6.6%) than in the controls (19.0%). There were no statistically significant differences in the genotype and allele frequencies of the XRCC1 codon 399, XRCC4 codon 247 and XRCC4 intron 3 insertion/deletion polymorphisms between the cases and controls.

CONCLUSIONS

The XRCC4 -1394T/G polymorphism was associated with susceptibility to endometriosis in an Iranian population.

Association between polymorphisms of XRCC1 and ADPRT genes and ovarian cancer survival with platinum-based chemotherapy in Chinese population

The role of DNA repair gene polymorphisms in cancer development, progression, and response to treatment has received increased attention. We conducted a prospective study to determine whether associations exist between two polymorphisms in XRCC1 and ADPRT and the outcomes of Chinese ovarian cancer patients treated with platinum-based chemotherapy. A total of 335 new cases of ovarian cancer were consecutively collected between May 2005 and May 2007. Follow-up lasted for 4 years, and the outcome measure was survival time. Individuals carrying XRCC1 194Trp/Trp had a longer survival time than did those with the Arg/Arg genotype. Similarly, those carrying XRCC1 399 Gln/Gln genotypes had 0.44-fold the risk of death than those with the Arg/Arg genotype. The combination of XRCC1 194 Trp allele and 399 Gln allele could decrease the death risk of ovarian cancer. In summary, this study is the first to evaluate the associations between polymorphisms in DNA repair gene polymorphism and the risk of ovarian cancer in Chinese population. Our study found a significant association between XRCC1 Arg399Gln and XRCC1 Arg194Trp polymorphism and the clinical outcome of ovarian cancer. Furthermore, studies with larger sample sizes are still needed to confirm these associations in Chinese population.