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1.  Extracellular Matrix Dynamics and Fetal Membrane Rupture 
Reproductive Sciences  2013;20(2):140-153.
The extracellular matrix (ECM) plays an important role in determining cell and organ function: (1) it is an organizing substrate that provides tissue tensile strength; (2) it anchors cells and influences cell morphology and function via interaction with cell surface receptors; and (3) it is a reservoir for growth factors. Alterations in the content and the composition of the ECM determine its physical and biological properties, including strength and susceptibility to degradation. The ECM components themselves also harbor cryptic matrikines, which when exposed by conformational change or proteolysis have potent effects on cell function, including stimulating the production of cytokines and matrix metalloproteinases (MMPs). Collectively, these properties of the ECM reflect a dynamic tissue component that influences both tissue form and function. This review illustrates how defects in ECM synthesis and metabolism and the physiological process of ECM turnover contribute to changes in the fetal membranes that precede normal parturition and contribute to the pathological events leading to preterm premature rupture of membranes (PPROM).
PMCID: PMC3826277  PMID: 22267536
extracellular matrix; PPROM; matrix metalloproteinase; collagens; fibronectin; amnion; chorion
2.  A Single Nucleotide Polymorphism in the Promoter of the LOXL1 Gene and Its Relationship to Pelvic Organ Prolapse and Preterm Premature Rupture of Membranes 
Pelvic organ prolapse (POP) and preterm premature rupture of the membranes (PPROM), two conditions which have in common weakening of the tensile strength of tissues, are thought to be caused, in part, by abnormal extracellular matrix synthesis and/or catabolism. We identified a new single nucleotide polymorphism (SNP) (NT_010194(LOXL1):g.45008784A>C) in the promoter of the LOXL1 gene, which is essential for elastin synthesis. Promoter studies showed that the minor “C” allele had significantly greater activity than the major “A” allele. Case-control studies examined the association of the alleles of this SNP with POP and PPROM. When comparing allele frequencies and genotypes in POP cases versus controls, no significant associations were found. A case-control study conducted in African-American neonates also found no significant associations between the promoter alleles and PPROM. We conclude that a functional SNP exists in the promoter region of LOXL1. Association studies suggest that the promoter SNP does not contribute significantly to risk of POP or PPROM.
PMCID: PMC2668743  PMID: 19182211
Lysyl oxidase-like 1; pelvic organ prolapse; preterm premature rupture of membranes; elastin
3.  Connective Tissue and Related Disorders and Preterm Birth: Clues to Genes Contributing to Prematurity 
Placenta  2009;30(3):207-215.
To identify candidate genes contributing to preterm birth, we examined the existing literature on the association between known disorders of connective tissue synthesis and metabolism and related diseases and prematurity. Our hypothesis was that abnormal matrix metabolism contributes to prematurity by increasing risk of preterm premature rupture of membranes (PPROM) and cervical incompetence. Based on this review, we identified gene mutations inherited by the fetus that could predispose to preterm birth as a result PPROM. The responsible genes include COL5A1, COL5A2, COL3A1, COL1A1, COL1A2, TNXB, PLOD1, ADAMTS2, CRTAP, LEPRE1 and ZMPSTE24. Marfan syndrome, caused by FBN1 mutations, and polymorphisms in the COL1A1 and TGFB1 genes have been associated with cervical incompetence. We speculate that an analysis of sequence variation at the loci noted above will reveal polymorphisms that may contribute to susceptibility to PPROM in the general population.
PMCID: PMC2673455  PMID: 19152976
Connective tissue; Genes; Preterm Birth; PPROM; Cervical incompetence
4.  Genetic Contributions to Disparities in Preterm Birth 
Pediatric research  2009;65(1):1-9.
Ethnic disparity in preterm delivery between African Americans and European Americans has existed for decades, and is likely the consequence of multiple factors, including socioeconomic status, access to care, environment, and genetics. This review summarizes existing information on genetic variation and its association with preterm birth in African Americans. Candidate gene-based association studies, in which investigators have evaluated particular genes selected primarily because of their potential roles in the process of normal and pathological parturition, provide evidence that genetic contributions from both mother and fetus account for some of the disparity in preterm births. To date, most attention has been focused on genetic variation in pro- and anti-inflammatory cytokine genes and their respective receptors. These genes, particularly the pro-inflammatory cytokine genes and their receptors, are linked to matrix metabolism since these cytokines increase expression of matrix degrading metalloproteinases. However, the role that genetic variants that are different between populations play in preterm birth cannot yet be quantified. Future studies based on genome wide association or admixture mapping may reveal other genes that contribute to disparity in prematurity.
PMCID: PMC2651992  PMID: 18787421
Genes; racial/ethnic disparities; preterm birth
6.  A novel ERAP2 haplotype structure in a Chilean population: implications for ERAP2 protein expression and preeclampsia risk 
Single nucleotide polymorphisms (SNPs) in the endoplasmic reticulum aminopeptidase 2 (ERAP2) gene are associated with preeclampsia (PE) in different populations. rs2549782, a coding variant (N392K) that significantly affects substrate specificity, is in linkage disequilibrium (LD) with rs2248374, a marker SNP associated with ERAP2 protein expression in previously studied populations. As a result of nonsense-mediated RNA decay, ERAP2 protein is not expressed from the rs2248374 G allele. We previously reported that the fetal rs2549782 minor G allele is associated with PE in African-Americans, but not in Chileans. In this study, we found that rs2549782 was in LD with rs2248374 in African-Americans, but not in Chileans. The unexpected lack of strong LD in Chileans raised the possibility that rs2248374 could be associated with PE in the absence of an association with rs2549782. However, we found no significant association for this allele with PE in Chileans. Chileans homozygous for the rs2248374 G allele did not express 110 kDa ERAP2 protein, consistent with nonsense-mediated RNA decay, and carriers of the rs2248374 A allele did. We conclude that the Chilean ERAP2 haplotype structure allows for the expression of the major T allele of rs2549782 encoding 392N, which could impact peptide trimming and antigen presentation. Our discovery of racial differences in genetic structure and association with PE reveal heretofore unrecognized complexity of the ERAP2 locus.
PMCID: PMC3769221  PMID: 24040622
African-Americans; Chileans; ERAP2; haplotype; preeclampsia
7.  Sex Hormone-Binding Globulin Genetic Variation: Associations with Type 2 Diabetes Mellitus and Polycystic Ovary Syndrome 
Minerva endocrinologica  2010;35(4):271-280.
Sex hormone-binding globulin (SHBG) is the primary plasma transport protein for sex steroid hormones and regulates the bioavailability of these hormones to target tissues. The gene encoding SHBG is complex and any of several polymorphisms in SHBG have been associated with alterations in circulating SHBG levels.
Epidemiological studies have revealed that low plasma SHBG levels are an early indicator of insulin resistance and predict the development of type 2 diabetes mellitus (T2DM) in both men and women. Although associations between low SHBG levels and risk of diabetes could be explained by the observation that elevations in insulin suppress hepatic SHBG production, recent studies documenting that the transmission of SHBG-altering polymorphisms are associated with risk of T2DM suggest that SHBG may have a more direct physiologic role in glucose homeostasis. However, the exact mechanism(s) underlying this association is not known.
Non-diabetic women with the polycystic ovary syndrome (PCOS), a common endocrine disorder that is associated with insulin resistance, similarly demonstrate lower levels of SHBG. In light of studies investigating polymorphisms in SHBG and T2DM, our group and others have hypothesized that SHBG may represent a candidate gene for PCOS. In this manuscript, we review studies investigating the association between SHBG polymorphisms and PCOS. In summary, multiple studies in women with PCOS confirm that certain genetic polymorphisms are associated with circulating SHBG levels, but they are not consistently associated with PCOS per se.
PMCID: PMC3683392  PMID: 21178921
genetic polymorphisms; polycystic ovary syndrome; sex hormone binding globulin; type 2 diabetes mellitus
Hypertension  2012;59(6):1249-1255.
Preeclampsia is characterized by increased thromboxane and decreased prostacyclin levels, which predate symptoms, and can explain some of the clinical manifestations of preeclampsia, including hypertension and thrombosis. In this study, we examined DNA methylation of the promoter region of the thromboxane synthase gene (TBXAS1) and the expression of thromboxane synthase in systemic blood vessels of normal pregnant and preeclamptic women. Thromboxane synthase is responsible for the synthesis of thromboxane A2, a potent vasoconstrictor and activator of platelets. We also examined the effect of experimentally induced DNA hypomethylation on the expression of thromboxane synthase in a neutrophil-like cell line (HL-60 cells), and in cultured vascular smooth muscle and endothelial cells. We found that DNA methylation of the TBXAS1 promoter was decreased, and thromboxane synthase expression was increased in omental arteries of preeclamptic women as compared to normal pregnant women. Increased thromboxane synthase expression was observed in vascular smooth muscles cells, endothelial cells and infiltrating neutrophils. Experimentally induced DNA hypomethylation only increased expression of thromboxane synthase in the neutrophil-like cell line, whereas tumor necrosis factor-α, a neutrophil product, increased its expression in cultured vascular smooth muscle cells. Our study suggests that epigenetic mechanisms and release of tumor necrosis factor-α by infiltrating neutrophils could contribute to the increased expression of thromboxane synthase in maternal systemic blood vessels, contributing to the hypertension and coagulation abnormalities associated with preeclampsia.
PMCID: PMC3355228  PMID: 22493072
preeclampsia; DNA methylation; thromboxane synthase; epigenetics; omental blood vessels; thromboxane A2
9.  The Interaction Effect of Bacterial Vaginosis and Periodontal Disease on the risk of Preterm Delivery 
American journal of perinatology  2011;29(5):347-352.
To determine if coexistence of periodontal disease (PD) and bacterial vaginosis (BV) is synergistic on the risk of spontaneous preterm delivery (sPTD).
Study Design
Secondary analysis of a prospective cohort study. Women were screened 6–20 weeks gestation for PD and BV. Groups were defined by presence of BV and stratified on PD. The primary outcome was sPTD <37 weeks gestation. Univariable, stratified and multivariable analyses were performed to estimate the main and interaction effects of BV and PD on sPTD.
Of 1453 women screened, 792 (54.5%) were diagnosed with BV. Neither women with BV in the first trimester nor PD were at higher risk of sPTD (risk ratio (RR) for BV 1.1, 95% confidence interval (CI) 0.8–1.5, RR for PD 0.9, 95% CI 0.7–1.3). The interaction between BV and PD did not statistically significantly impact the odds of sPTD.
Coexistence of PD and BV did not have a synergistic effect on sPTD.
PMCID: PMC3613845  PMID: 22105437
bacterial vaginosis; periodontal disease; preterm delivery
10.  Catechol-O-Methyltransferase (COMT) Single Nucleotide Polymorphisms and Haplotypes Are Not Major Risk Factors for Polycystic Ovary Syndrome 
Polycystic ovary syndrome (PCOS) is an endocrine disorder that affects 5–8% of reproductive age women. The primary features of PCOS are hyperandrogenemia, chronic anovulation and infertility. It has been suggested that defects in ovarian steroid metabolism contribute to the follicular growth arrest and abnormal production of ovarian steroid hormones that are characteristic of PCOS. 2-methoxyestradiol (2-ME) is formed by the action of catechol-O-methyltransferase (COMT) on 2-hydroxyestradiol. COMT expression is increased in the follicles and ovarian stroma of women with PCOS. Moreover, 2-ME decreases granulosa cell proliferation and steroidogenesis, raising the possibility that ovarian dysfunction associated with PCOS is due, in part, to increased synthesis of 2-ME resulting from increased COMT activity. Four single-nucleotide polymorphisms (SNPs) (rs6269, rs4633, rs4818, rs4680) in the COMT gene characterize haplotypes, which are associated with large variations in COMT enzymatic activity. The aim of this study was to determine whether individual COMT SNPs and the COMT haplotypes are associated with PCOS using a family-based test of association and linkage. Additionally, we examined the relationships between COMT SNPs and haplotypes with quantitative variables usually assessed in the evaluation of women with PCOS. There were no significant correlations between genotype and total testosterone, non-SHBG bound testosterone and BMI. However, we found that the prolactin level in women with PCOS varied significantly with COMT haplotype, and suggest that this association reflects a genetic factor influencing the stress response. Our findings suggest that common variants and haplotypes of the COMT gene are not major contributors to risk for PCOS, but that COMT genotype may influence prolactin levels.
PMCID: PMC3264817  PMID: 22178088
Catechol-O-Methyltransferase; COMT; polycystic ovary syndrome; prolactin5
11.  Replication of Association of DENND1A and THADA Variants with Polycystic Ovary Syndrome in European Cohorts 
Journal of medical genetics  2011;49(2):90-95.
Polycystic ovary syndrome (PCOS) is a complex endocrine disorder with a strong familial component. PCOS is characterized by hyperandrogenemia and irregular menses. A recent genome wide association study of PCOS in a Chinese cohort identified three reproducible PCOS susceptibility loci mapping to 2p16.3 (luteinizing hormone/choriogonadotropin receptor; LHCGR), 2p21 (thyroid associated protein; THADA), and 9q33.3 (DENN/MADD domain containing 1A; DENNDIA). The impact of these loci in non-Chinese PCOS cohorts remains to be determined.
We tested association with PCOS of seven single nucleotide polymorphisms mapping to the three Chinese PCOS loci in two European-derived PCOS cohorts (Cohort A = 939 cases and 957 controls; Cohort B = 535 cases and 845 controls). Cases fulfilled the NICHD criteria for PCOS. Variation in DENND1A was strongly associated with PCOS in our cohort (pcombined cohorts=10−8 ); multiple variants in THADA were also associated with PCOS, while there was no significant evidence for association of LHCGR variation with PCOS. We had greater than 80% power to detect an effect of similar size as was observed by Chen et al. for DENND1A and THADA but reduced power (at <40%) for LHCGR at p=0.0001. We had sufficient power (57-88%) for LHCGR at p=0.01.
At least two of the PCOS susceptibility loci identified in the Chinese PCOS GWAS (DENND1A and THADA) are also associated with PCOS in European-derived populations, and therefore likely to be important in the etiology of PCOS regardless of ethnicity. Our analysis of the LHCGR gene was not sufficiently powered to detect modest effects.
PMCID: PMC3536488  PMID: 22180642
PCOS; DENND1A; THADA; genome-wide association study
12.  Sex Hormone-Binding Globulin and Type 2 Diabetes Mellitus 
Sex hormone-binding globulin (SHBG) has emerged as one of the multiple genetic and environmental factors that potentially contribute to the pathophysiology of Type 2 diabetes mellitus (T2DM). In addition to epidemiologic studies demonstrating a consistent relationship between decreased levels of serum SHBG and incident T2DM, recent genetic studies also reveal that transmission of specific polymorphisms in the SHBG gene influence risk of T2DM. On the molecular level, elucidation of the multiple interactions between SHBG and its receptors in various target tissues, suggest physiologic roles for SHBG that are more complex than the simple transport of sex hormones in serum. Taken together, these data provide support for an expanded role of SHBG in the pathophysiology of insulin resistance and T2DM.
PMCID: PMC3351377  PMID: 22047952
genetic polymorphisms; sex hormone binding globulin; type 2 diabetes mellitus
13.  The Momedemameter: An Affordable Preeclampsia Detector For Low Resource Environments 
Journal of medical devices  2009;3(1):014501-014503.
Preeclampsia, a pregnancy-specific disorder, is the third leading cause of maternal morbidity and mortality worldwide.
Method of Approach
To develop a device to detect preeclampsia in pregnant women living in low resource environments, a method was needed that had to be very low cost and, preferably, easily monitored by the woman herself. Due to the high cost and expertise involved in monitoring the two diagnostic criteria of preeclampsia (elevated blood pressure and proteinuria), edema, an indicator of preeclampsia was chosen instead.
The general principle of the method is to have each pregnant woman, early in pregnancy, fitted, on either her wrist or ankle, with a detection band, which is set to a preset expansion limit (e.g., expansion by 5%). When edema causes that body part to swell to the limit, the pregnant mother knows that she should seek medical assistance.
The resulting prototype device and calibration method requires little knowledge, and is very durable, cost-effective and portable.
PMCID: PMC3307143  PMID: 22437036
preeclampsia indicator; edema detector
14.  Medicaid and Preterm Births in Virginia: An Analysis of Recent Outcomes 
Journal of Women's Health  2010;19(11):1969-1975.
The study objectives were to evaluate adequacy of prenatal care and risk for preterm birth among Medicaid clients in Virginia and to determine if payment method is associated with the risk of preterm birth.
Birth certificate data for the Commonwealth of Virginia for 2007 and 2008 were linked with Medicaid claims data. Analysis was limited to singleton births. Three payment methods were evaluated: private insurance, self-pay, and Medicaid. The prevalence of preterm birth for each level of prenatal care defined by the Kotelchuck prenatal care index was assessed for each payment method. Unconditional logistic regression modeling was used to assess the association between payment method and preterm birth risk while controlling for known preterm birth risk factors.
Preterm birth prevalences (95% confidence interval [CI]) for the different payment methods were 7.9% (4.79-8.07) for the privately insured, 10.1% (9.57-10.60) for the self-pay group, and 10.2% (9.95-10.45) for Medicaid recipients. Compared with those with private insurance, women on Medicaid had an adjusted odds ratio (OR) for preterm birth (95% CI) of 0.99 (0.94-1.03). Self-pay mothers had a 32% increase in the odds of preterm birth relative to the privately insured. All payment groups show a trend toward significant reduction in preterm birth prevalence as adequacy of prenatal care improved from inadequate to adequate. Medicaid enrollees had a high prevalence of known risk factors, including smoking and illicit drug use and cervical insufficiency.
When known risk factors have been controlled, preterm birth risk for Medicaid enrollees did not differ significantly from the privately insured.
PMCID: PMC2971635  PMID: 20831442
15.  Is laminin gamma-1 (LAMC1) a candidate gene for advanced pelvic organ prolapse? 
1) To determine allele frequencies of 3 LAMC1 single nucleotide polymorphisms (SNPs) in Caucasian and African-American (AA) women with > Stage II POP (cases) and in ethnicity-matched controls with < Stage 2 POP. 2) To determine if LAMC1 is associated with POP within ethnic groups.
Study design
Allelic discrimination was performed for LAMC1 SNPs rs10911193 (C/T), rs20563 (A/G), and rs20558 (T/C). SNP and haplotype-specific tests were used to examine associations between POP, ethnicity, and LAMC1.
411 women were enrolled. Significant differences in allele and haplotype frequencies existed amongst AA and Caucasians: rs10911193 “T” (p=0.0014); rs20563 “G” (p<0.0001); rs20558 “C” (p<0.0001); rs20563, rs20558 “GC” (p<0.0001); and rs20563, rs20558 “AT” (p<0.0001). No significant associations between POP and LAMC1 SNPs or haplotypes were found within ethnicities.
While significant differences were identified between AA and Caucasian women, no associations were found between any LAMC1 gene variant and advanced POP.
PMCID: PMC2866811  PMID: 20223449
familial pelvic organ prolapsed; genetics; genetic predisposition; lamimin gamma 1; LAMC1; POP
16.  Functional Deficiencies and a Reduced Response to Calcium in the Flagellum of Mouse Sperm Lacking SPAG16L1 
Biology of Reproduction  2009;82(4):736-744.
The Spag16L gene codes for a protein that is localized to the central apparatus which is essential for normal sperm motility and male fertility. Sperm from mice homozygous for a targeted deletion of the Spag16L gene were examined to assess their flagellar motor functions compared with age- and strain-matched control sperm. Sperm were also demembranated with Triton X-100 and examined for their ability to respond to free calcium, as well as for their ability to undergo microtubule sliding driven by dynein action. In addition, the passive flagella, inhibited by sodium metavanadate to disable the dyneins, were examined for mechanical abnormalities. Live Spag16L-null sperm exhibited much less bending of the flagellum during the beat. The amount of microtubule sliding in the R-bend direction of the beat was selectively restricted, which suggests that there is limited activation of the dyneins on one side of the axoneme in the live cells. This is corroborated by the results on detergent-extracted sperm models. The flagellar response to calcium is greatly reduced. The calcium response requires the activation of the dyneins on outer doublets 1, 2, 3, and 4. These are the same dyneins required for R-bend formation. In axonemes prepared to disintegrate by microtubule sliding, we observed little or no extrusion of doublets 1 and 2, consistent with a reduced activity of their dyneins. This deficit in motor function, and an increased rigidity of the midpiece region which we detected in the passive flagella, together can explain the observed motility characteristics of the Spag16L-null sperm.
Mouse sperm lacking SPAG16L have altered motility and a reduced response to calcium.
PMCID: PMC2842488  PMID: 20042536
axoneme; calcium; central pair; ciliopathies; dynein; hyperactivation
17.  Medicaid and Preterm Birth and Low Birth Weight: The Last Two Decades 
Journal of Women's Health  2010;19(3):443-451.
To determine if (1) birth outcomes among women on Medicaid differ significantly from outcomes of those with private insurance, after controlling for known risk factors, and (2) enhanced prenatal care influences care use and birth outcomes.
This is a review of studies published between 1989 and 2009 that examined birth outcomes (1) between women on Medicaid and those with private insurance and (2) among Medicaid enrollees who received comprehensive prenatal care.
When corrected for risk variables, birth outcomes are not different between private insurance and Medicaid patients. The impact of comprehensive prenatal care programs on birth outcomes varies across states and regions.
There is a need for critical evaluation of comprehensive programs in a regional and state context to determine opportunities for improvement.
PMCID: PMC2867587  PMID: 20141370
18.  Epistasis between COMT and MTHFR in Maternal-Fetal Dyads Increases Risk for Preeclampsia 
PLoS ONE  2011;6(1):e16681.
Preeclampsia is a leading cause of perinatal morbidity and mortality. This disorder is thought to be multifactorial in origin, with multiple genes, environmental and social factors, contributing to disease. One proposed mechanism is placental hypoxia-driven imbalances in angiogenic and anti-angiogenic factors, causing endothelial cell dysfunction. Catechol-O-methyltransferase (Comt)-deficient pregnant mice have a preeclampsia phenotype that is reversed by exogenous 2-methoxyestradiol (2-ME), an estrogen metabolite generated by COMT. 2-ME inhibits Hypoxia Inducible Factor 1α, a transcription factor mediating hypoxic responses. COMT has been shown to interact with methylenetetrahydrofolate reductase (MTHFR), which modulates the availability of S-adenosylmethionine (SAM), a COMT cofactor. Variations in MTHFR have been associated with preeclampsia. By accounting for allelic variation in both genes, the role of COMT has been clarified. COMT allelic variation is linked to enzyme activity and four single nucleotide polymorphisms (SNPs) (rs6269, rs4633, rs4680, and rs4818) form haplotypes that characterize COMT activity. We tested for association between COMT haplotypes and the MTHFR 677 C→T polymorphism and preeclampsia risk in 1103 Chilean maternal-fetal dyads. The maternal ACCG COMT haplotype was associated with reduced risk for preeclampsia (P = 0.004), and that risk increased linearly from low to high activity haplotypes (P = 0.003). In fetal samples, we found that the fetal ATCA COMT haplotype and the fetal MTHFR minor “T” allele interact to increase preeclampsia risk (p = 0.022). We found a higher than expected number of patients with preeclampsia with both the fetal risk alleles alone (P = 0.052) and the fetal risk alleles in combination with a maternal balancing allele (P<0.001). This non-random distribution was not observed in controls (P = 0.341 and P = 0.219, respectively). Our findings demonstrate a role for both maternal and fetal COMT in preeclampsia and highlight the importance of including allelic variation in MTHFR.
PMCID: PMC3031618  PMID: 21304959
19.  Racial Differences in Genetic and Environmental Risk to Preterm Birth 
PLoS ONE  2010;5(8):e12391.
Preterm birth is more prevalent in African Americans than European Americans and contributes to 3.4 times more African American infant deaths. Models of social inequity do not appreciably account for this marked disparity and molecular genetic studies have yet to characterize whether allelic differences that exist between races contribute to this gap. In this study, biometrical genetic models are applied to a large mixed-race sample consisting of 733,339 births to measure the extent that heritable factors and environmental exposures predict the timing of birth and explain differences between racial groups. Although we expected significant differences in mean gestational age between racial groups, we did not anticipate the variance of gestational age in African Americans (σ2 = 7.097) to be nearly twice that of European Americans (σ2 = 3.764). Our results show that this difference in the variance of gestational age can largely be attributed to environmental sources; which were 3.1 times greater in African Americans. Specifically, environmental factors that change between pregnancies, versus exposures that influence all pregnancies within a family, are largely responsible for the increased reproductive heterogeneity observed in African American mothers. Although the contribution of both fetal and maternal genetic factors differed between race categories, genetic studies may best be directed to understanding the differences in the socio-cultural sources of this heterogeneity, and their possible interaction with genetic differences within and between races. This study provides a comprehensive description of the relative genetic and environmental contributions to racial differences in gestational age.
PMCID: PMC2928274  PMID: 20811627
20.  Estimating Fetal and Maternal Genetic Contributions to Premature Birth From Multiparous Pregnancy Histories of Twins Using MCMC and Maximum-Likelihood Approaches 
The analysis of genetic and environmental contributions to preterm birth is not straightforward in family studies, as etiology could involve both maternal and fetal genes. Markov Chain Monte Carlo (MCMC) methods are presented as a flexible approach for defining user-specified covariance structures to handle multiple random effects and hierarchical dependencies inherent in children of twin (COT) studies of pregnancy outcomes. The proposed method is easily modified to allow for the study of gestational age as a continuous trait and as a binary outcome reflecting the presence or absence of preterm birth. Estimation of fetal and maternal genetic factors and the effect of the environment are demonstrated using MCMC methods implemented in WinBUGS and maximum likelihood methods in a Virginia COT sample comprising 7,061 births. In summary, although the contribution of maternal and fetal genetic factors was supported using both outcomes, additional births and/or extended relationships are required to precisely estimate both genetic effects simultaneously. We anticipate the flexibility of MCMC methods to handle increasingly complex models to be of particular relevance for the study of birth outcomes.
PMCID: PMC2913409  PMID: 19653833
preterm birth; fetal; maternal; genetic; environment; MCMC; ML
21.  PDE8A genetic variation, polycystic ovary syndrome and androgen levels in women 
Molecular Human Reproduction  2009;15(8):459-469.
Polycystic ovary syndrome (PCOS) is characterized by excessive theca cell androgen secretion, dependent upon LH, which acts through the intermediacy of 3′,5′-cyclic adenosine monophosphate (cAMP). cAMP signaling pathways are controlled through regulation of its synthesis by adenylyl cyclases, and cAMP degradation by phosphodiesterases (PDEs). PDE8A, a high-affinity cAMP-specific PDE is expressed in the ovary and testis. Leydig cells from mice with a targeted mutation in the Pde8a gene are sensitized to the action of LH in terms of testosterone production. These observations led us to evaluate the human PDE8A gene as a PCOS candidate gene, and the hypothesis that reduced PDE8A activity or expression would contribute to excessive ovarian androgen production. We identified a rare variant (R136Q; NM_002605.2 c.407G > A) and studied another known single nucleotide polymorphism (SNP) (rs62019510, N401S) in the PDE8A coding sequence causing non-synonymous amino acid substitutions, and a new SNP in the promoter region (NT_010274.16:g.490155G > A). Although PDE8A kinetics were consistent with reduced activity in theca cell lysates, study of the expressed variants did not confirm reduced activity in cell-free assays. Sub-cellular localization of the enzyme was also not different among the coding sequence variants. The PDE8A promoter SNP and a previously described promoter SNP did not affect promoter activity in in vitro assays. The more common coding sequence SNP (N401S), and the promoter SNPs were not associated with PCOS in our transmission/disequilibrium test-based analysis, nor where they associated with total testosterone or dehydroepiandrosterone sulfate levels. These findings exclude a significant role for PDE8A as a PCOS candidate gene, and as a Las major determinant of androgen levels in women.
PMCID: PMC2709315  PMID: 19482904
PDE8A; polycystic ovary syndrome; androgens; theca; SNP
22.  Transcriptional Regulation of an Axonemal Central Apparatus Gene, Sperm-associated Antigen 6, by a SRY-related High Mobility Group Transcription Factor, S-SOX5* 
The Journal of Biological Chemistry  2010;285(40):30496-30505.
SOX5 is a transcription factor with homology to the high mobility group box region of the testis-determining factor, SRY. Both the mouse and human SOX5 genes encode a 48-kDa SOX5 protein (S-SOX5) that is only present in tissues containing cells with motile cilia/flagella. The mammalian sperm-associated antigen 6 gene (SPAG6) encodes an axoneme central apparatus protein. Because human and mouse SPAG6 gene promoters contain multiple potential binding sites for SOX5, SPAG6 gene regulation by S-SOX5 was investigated in BEAS-2B cells, a line derived from human bronchial cells. Like FOXJ1, a transcription factor known to be essential for motile ciliogenesis, S-SOX5 stimulated mouse and human SPAG6 promoter function in BEAS-2B cells, but the effect was abrogated when the SOX5 binding sites were mutated or deleted. S-SOX5 and FOXJ1 functioned cooperatively in stimulating SPAG6 promoter activity. The SPAG6 message was up-regulated when S-SOX5 was overexpressed in BEAS-2B cells, and silencing of S-SOX5 by RNA interference down-regulated SPAG6 transcripts. Chromatin immunoprecipitation and EMSA experiments demonstrated that S-SOX5 associates with the SPAG6 promoter directly. The present study demonstrates that SPAG6 is a S-SOX5 target gene, indicating a key role for S-SOX5 in the formation and function of motile cilia.
PMCID: PMC2945543  PMID: 20668334
DNA-Protein Interaction; Gene Regulation; Promoters; Site-directed Mutagenesis; Sperm; Central Apparatus; Motile Cilia; SOX5; SPAG6; Transcription Regulation
23.  Health disparities in risk for cervical insufficiency 
Human Reproduction (Oxford, England)  2010;25(11):2894-2900.
The purpose of the study was to examine racial/ethnic differences in cervical insufficiency risk.
We used the US 2005 Natality data file. Analysis was limited to singleton births. The prevalence of cervical insufficiency was examined by the maternal characteristic for each racial group. Unconditional logistic regression modeling was used to assess the association between race and cervical insufficiency while controlling for confounders.
Cervical insufficiency risk for Black women was more than twice that for their White counterparts [odds ratio (OR) (95% confidence interval (CI)) of 2.45 (2.22–2.71)]. Prior pregnancy termination showed a dose–response relationship with cervical insufficiency. Compared with women with no history of prior pregnancy termination, primiparous women who have had one pregnancy termination had an OR (95% CI) of 2.49 (2.23–2.77). The OR for two, three and four or more terminations were 4.66 (4.07–5.33), 8.07 (6.77–9.61) and 12.36 (10.19–15.00), respectively. Other predictors of cervical insufficiency included previous preterm birth, parity, marital status, renal disease, history of diabetes, polyhydramnios and anemia.
There were significant racial/ethnic disparities with Black women having increased cervical insufficiency risk, independent of other studied factors. Prior pregnancy termination is also a major risk factor for cervical insufficiency. The White/Black disparity is evident in both primiparous and multiparous women.
PMCID: PMC2955555  PMID: 20643692
cervical insufficiency; pregnancy termination; race; ethnicity
24.  Drawing the line between commensal and pathogenic Gardnerella vaginalis through genome analysis and virulence studies 
BMC Genomics  2010;11:375.
Worldwide, bacterial vaginosis (BV) is the most common vaginal disorder. It is associated with risk for preterm birth and HIV infection. The etiology of the condition has been debated for nearly half a century and the lack of knowledge about its cause and progression has stymied efforts to improve therapy and prevention. Gardnerella vaginalis was originally identified as the causative agent, but subsequent findings that it is commonly isolated from seemingly healthy women cast doubt on this claim. Recent studies shedding light on the virulence properties of G. vaginalis, however, have drawn the species back into the spotlight.
In this study, we sequenced the genomes of a strain of G. vaginalis from a healthy woman, and one from a woman with bacterial vaginosis. Comparative analysis of the genomes revealed significant divergence and in vitro studies indicated disparities in the virulence potential of the two strains. The commensal isolate exhibited reduced cytotoxicity and yet the cytolysin proteins encoded by the two strains were nearly identical, differing at a single amino acid, and were transcribed at similar levels. The BV-associated strain encoded a different variant of a biofilm associated protein gene and demonstrated greater adherence, aggregation, and biofilm formation. Using filters with different pore sizes, we found that direct contact between the bacteria and epithelial cells is required for cytotoxicity.
The results indicated that contact is required for cytotoxicity and suggested that reduced cytotoxicity in the commensal isolate could be due to impaired adherence. This study outlines two distinct genotypic variants of G. vaginalis, one apparently commensal and one pathogenic, and presents evidence for disparate virulence potentials.
PMCID: PMC2890570  PMID: 20540756
25.  Expression Profile of Male Germ Cell-Associated Genes in Mouse Embryonic Stem Cell Cultures Treated with All-Trans Retinoic Acid and Testosterone 
Cells that morphologically and functionally resemble male germ cells can be spontaneously derived from ES cells. However, this process is inefficient and unpredictable suggesting that the expression pattern of male germ cell associated genes during spontaneous ES cell differentiation does not mimic the in vivo profiles of the genes. Thus, in the present study, the temporal expression profile of genes expressed at different stages of male germ cell development was examined in differentiating ES cells. The effect of all-trans retinoic acid (RA) which is a known inducer of primordial germ cell (PGC) proliferation/survival in vitro and testosterone which is required for spermatogenesis in vivo on the expression of these genes was also determined. Each of the 12 genes analyzed exhibited one of four temporal expression patterns in untreated differentiating ES cells: progressively decreased (Dpp3a, Sycp3, Msy2), initially low and then increased (Stra8, Sycp1, Dazl, Act, Prm1), initially decreased and then increased (Piwil2, Tex14), or relatively unchanged (Akap3, Odf2). RA-treated cells exhibited increased expression of Stra8, Dazl, Act, and Prm1 and suppressed expression of Dpp3a compared to untreated controls. Furthermore, testosterone increased expression of Stra8 while the combination of RA and testosterone synergistically increased expression of Act. Our findings establish a comprehensive profile of male germ cell gene expression during spontaneous differentiation of murine ES cells and describe the capacity of RA and testosterone to modulate the expression of these genes. Furthermore, these data represent an important first step in designing a plausible directed differentiation protocol for male germ cells.
PMCID: PMC2664383  PMID: 18425777
Spermatogenesis; Gene Expression Profiling; Real-Time PCR; Embryoid Bodies

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