Influence of Common Non-Synonymous Toll-like Receptor 4 Polymorphisms on Bronchopulmonary Dysplasia and Prematurity in Human Infants

Bronchopulmonary dysplasia (BPD) is a common chronic lung disease and major risk factor for severe respiratory syncytial virus (RSV) infection among preterm infants. The Toll-like receptor 4 (TLR4) is involved in oxidative injury responses in the lungs. Two non-synonymous single nucleotide polymorphisms in the TLR4 gene have been associated with RSV infection in children. However, it is unclear to what extent this association is confounded by BPD or prematurity. In this study, we analyzed two population-based cohorts of preterm infants at risk for BPD as well as ethnicity-matched infants born at term, to test whether the TLR4 polymorphisms Asp299Gly (rs4986790) and Thr399Ile (rs4986791) are independently associated with BPD or premature birth. In a Canadian cohort (n = 269) composed of a majority of Caucasian preterm infants (BPD incidence of 38%), the TLR4-299 heterozygous genotype was significantly under-represented in infants without BPD (1.6% of infants versus 12% in infants with severe BPD) after adjusting for twins, ethnicity, gestational age, birth weight and gender (p = 0.014). This association was not replicated in a Finnish cohort (n = 434) of premature singletons or first-born siblings of Caucasian descent, although the incidence of BPD was substantially lower in this latter population (15%). We did not detect a significant association (>2-fold) between TLR4 genotypes and prematurity (p>0.05). We conclude that these TLR4 genotypes may have, at best, a modest influence on BPD severity in some populations of high-risk preterm infants. Further studies are warranted to clarify how clinical heterogeneity may impact genetic susceptibility to BPD

A Potential Novel Spontaneous Preterm Birth Gene, AR, Identified by Linkage and Association Analysis of X Chromosomal Markers

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Human placental proteomics and exon variant studies link AAT/SERPINA1 with spontaneous preterm birth

Background: Preterm birth is defined as live birth before 37 completed weeks of pregnancy, and it is a major problem worldwide. The molecular mechanisms that lead to onset of spontaneous preterm birth are incompletely understood. Prediction and evaluation of the risk of preterm birth is challenging as there is a lack of accurate biomarkers. In this study, our aim was to identify placental proteins that associate with spontaneous preterm birth. Methods: We analyzed the proteomes from placentas to identify proteins that associate with both gestational age and spontaneous labor. Next, rare and potentially damaging gene variants of the identified protein candidates were sought for from our whole exome sequencing data. Further experiments we performed on placental samples and placenta-associated cells to explore the location and function of the spontaneous preterm labor-associated proteins in placentas. Results: Exome sequencing data revealed rare damaging variants in SERPINA1 in families with recurrent spontaneous preterm deliveries. Protein and mRNA levels of alpha-1 antitrypsin/SERPINA1 from the maternal side of the placenta were downregulated in spontaneous preterm births. Alpha-1 antitrypsin was expressed by villous trophoblasts in the placenta, and immunoelectron microscopy showed localization in decidual fibrinoid deposits in association with specific extracellular proteins. siRNA knockdown in trophoblast-derived HTR8/SVneo cells revealed that SERPINA1 had a marked effect on regulation of the actin cytoskeleton pathway, Slit–Robo signaling, and extracellular matrix organization. Conclusions: Alpha-1 antitrypsin is a protease inhibitor. We propose that loss of the protease inhibition effects of alpha-1 antitrypsin renders structures critical to maintaining pregnancy susceptible to proteases and inflammatory activation. This may lead to spontaneous premature birth.publishedVersionPeer reviewe

A study of genes encoding cytokines (IL6, IL10, TNF), cytokine receptors (IL6R, IL6ST), and glucocorticoid receptor (NR3C1) and susceptibility to bronchopulmonary dysplasia

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EPHB2 germline variants in patients with colorectal cancer or hyperplastic polyposis

BACKGROUND: Ephrin receptor B2 (EPHB2) has recently been proposed as a novel tumor suppressor gene in colorectal cancer (CRC). Inactivation of the gene has been shown to correlate with progression of colorectal tumorigenesis, and somatic mutations have been reported in both colorectal and prostate tumors. METHODS: Here we have analyzed the EPHB2 gene for germline alterations in 101 individuals either with 1) CRC and a personal or family history of prostate cancer (PC), or 2) intestinal hyperplastic polyposis (HPP), a condition associated with malignant degeneration such as serrated adenoma and CRC. RESULTS: Four previously unknown missense alterations were observed, which may be associated with the disease phenotype. Two of the changes, I361V and R568W, were identified in Finnish CRC patients, but not in over 300 Finnish familial CRC or PC patients or more than 200 population-matched healthy controls. The third change, D861N, was observed in a UK HPP patient, but not in additional 40 UK HPP patients or in 200 UK healthy controls. The fourth change R80H, originally identified in a Finnish CRC patient, was also found in 1/106 familial CRC patients and in 9/281 healthy controls and is likely to be a neutral polymorphism. CONCLUSION: We detected novel germline EPHB2 alterations in patients with colorectal tumors. The results suggest a limited role for these EPHB2 variants in colon tumor predisposition. Further studies including functional analyses are needed to confirm this

Immature surfactant protein-B impairs the antioxidant capacity of HDL

Abstract Circulating immature surfactant protein B (proSP-B) forms emerged as the most reliable lung-specific circulating marker for alveolar-capillary membrane (ACM) dysfunction and for the overall clinical status of heart failure (HF). Notably, in terms of HF hospitalization, immature SP-B overwhelms the prognostic role of other most frequently used clinical parameters such as those related to lung dysfunction. The strong prognostic value of circulating proSP-B in HF suggests more widespread and possible systemic effects. Thus, we assessed the plasma distribution of proSP-B evaluating whether it exists in a lipoprotein-bound form and its impact on lipoprotein structure and function. ProSP-B forms were detectable in high-density lipoprotein (HDL) only. To assess the impact of proSP-B on HDL, HDL from healthy subjects were enriched with proSP-B produced by a stably transfected CHO cell line that specifically expresses and releases the human proSP-B. After enrichment, HDL size and lipoprotein electrophoretic mobility, and protein composition did not show apparent differences. HDL antioxidant capacity (HOI), assessed as their ability to inhibit air-induced LDL oxidation, was impaired after proSP-B enrichment. HOI was also higher in HF patients with respect to age-matched control healthy subjects (p = 0.013). Circulating proSP-B, besides its potential role as a specific marker for ACM dysfunction in HF patients with diagnostic and prognostic value, binds to human HDL impairing their antioxidant capacity. These findings shed light on proSP-B as a molecule that contributes to the reduction of the defense against oxidative stress, a key mediator in the pathogenesis of HF

Diagnostic utility of next-generation sequencing-based panel testing in 543 patients with suspected skeletal dysplasia

Correction: Volume17, Issue1 Article Number 59 DOI: 10.1186/s13023-022-02242-8 Published FEB 17 2022Background Skeletal dysplasia is typically diagnosed using a combination of radiographic imaging, clinical examinations, and molecular testing. Identifying a molecular diagnosis for an individual with a skeletal dysplasia can lead to improved clinical care, guide future medical management and treatment, and inform assessment of risk for familial recurrence. The molecular diagnostic utility of multi-gene panel testing using next-generation sequencing (NGS) has not yet been characterized for an unselected population of individuals with suspected skeletal dysplasia. In this study, we retrospectively reviewed patient reports to assess the diagnostic yield, reported variant characteristics, impact of copy number variation, and performance in prenatal diagnostics of panel tests for variants in genes associated with skeletal dysplasia and growth disorders. Results Clinical reports of consecutive patients with a clinical indication of suspected skeletal dysplasia who underwent panel testing were examined. The 543 patients included in the study submitted samples for diagnostic genetic testing with an indication of suspected skeletal dysplasia or growth disorder and received one of three nested panel tests. A molecular diagnosis was established in 42.0% of patients (n = 228/543). Diagnostic variants were identified in 71 genes, nearly half of which (n = 35, 49.3%) contributed uniquely to a molecular diagnosis for a single patient in this cohort. Diagnostic yield was significantly higher among fetal samples (58.0%, n = 51/88) than postnatal samples (38.9%, n = 177/455; z = 3.32, p < 0.0009). Diagnostic variants in fetal cases were identified across 18 genes. Thirteen diagnostic CNVs were reported, representing 5.7% of diagnostic findings and ranging in size from 241-bp to whole chromosome aneuploidy. Additionally, 11.4% (36/315) of non-diagnostic patient reports had suspicious variants of unknown significance (VUS), in which additional family studies that provide segregation data and/or functional characterization may result in reclassification to likely pathogenic. Conclusions These findings demonstrate the utility of panel testing for individuals with a suspected skeletal dysplasia or growth disorder, with a particularly high diagnostic yield seen in prenatal cases. Pursuing comprehensive panel testing with high-resolution CNV analysis can provide a diagnostic benefit, given the considerable phenotype overlap amongst skeletal dysplasia conditions.Peer reviewe

Risk of spontaneous preterm birth and fetal growth associates with fetal SLIT2

Abstract Spontaneous preterm birth (SPTB) is the leading cause of neonatal death and morbidity worldwide. Both maternal and fetal genetic factors likely contribute to SPTB. We performed a genome-wide association study (GWAS) on a population of Finnish origin that included 247 infants with SPTB (gestational age [GA] &lt; 36 weeks) and 419 term controls (GA 38–41 weeks). The strongest signal came within the gene encoding slit guidance ligand 2 (SLIT2; rs116461311, minor allele frequency 0.05, p = 1.6×10−6). Pathway analysis revealed the top-ranking pathway was axon guidance, which includes SLIT2. In 172 very preterm-born infants (GA &lt;32 weeks), rs116461311 was clearly overrepresented (odds ratio 4.06, p = 1.55×10−7). SLIT2 variants were associated with SPTB in another European population that comprised 260 very preterm infants and 9,630 controls. To gain functional insight, we used immunohistochemistry to visualize SLIT2 and its receptor ROBO1 in placentas from spontaneous preterm and term births. Both SLIT2 and ROBO1 were located in villous and decidual trophoblasts of embryonic origin. Based on qRT-PCR, the mRNA levels of SLIT2 and ROBO1 were higher in the basal plate of SPTB placentas compared to those from term or elective preterm deliveries. In addition, in spontaneous term and preterm births, placental SLIT2 expression was correlated with variations in fetal growth. Knockdown of ROBO1 in trophoblast-derived HTR8/SVneo cells by siRNA indicated that it regulate expression of several pregnancy-specific beta-1-glycoprotein (PSG) genes and genes involved in inflammation. Our results show that the fetal SLIT2 variant and both SLIT2 and ROBO1 expression in placenta and trophoblast cells may be correlated with susceptibility to SPTB. SLIT2-ROBO1 signaling was linked with regulation of genes involved in inflammation, PSG genes, decidualization and fetal growth. We propose that this receptor-ligand couple is a component of the signaling network that promotes SPTB

Pedigrees of the seven families with recurrent spontaneous preterm births analyzed in the linkage analysis of X chromosomal markers.

<p>Individuals born preterm are shown by half-black symbols. Squares represent males and circles females. Individuals analyzed in the linkage analysis are indicated by a number (<i>n</i> = 89). The diamonds denote an unspecified number of term infants, the smaller diamonds with a line through the symbol represent a miscarriage, and the lines through the other symbols indicate that the person is deceased. Gestational ages and years of birth for the family members born preterm are shown in Table S1. Linkage analysis was performed in two settings: 1) being spontaneously born preterm as the phenotype (affected offspring phenotype, <i>n_affected</i>  = 41), and 2) giving spontaneous preterm births as the phenotype (affected mother phenotype, <i>n_affected</i>  = 21). These pedigrees have been previously shown in the supplementary material of our linkage study of SPTB performed using autosomal markers <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0051378#pone.0051378-Haataja1" target="_blank">[27]</a>.</p

Clinical characteristics of the case study populations of spontaneous preterm birth.

a<p>Mismatch in the numbers of mothers and offspring is due to occasional low quality of DNA samples.</p>b<p>Mean ± standard deviation (range).</p