Association of surfactant protein B gene polymorphisms (C/A-18, C/T1580, intron 4 and A/G9306) and haplotypes with bronchopulmonary dysplasia in chinese han population

Genetics of bronchopulmonary dysplasia: An update

Bronchopulmonary dysplasia (BPD) is a multi-factorial disease that results from multiple clinical factors, including lung immaturity, mechanical ventilation, oxidative stress, pulmonary congestion due to increasing cardiac blood shunting, nutritional and immunological factors. Twin studies have indicated that susceptibility to BPD can be strongly inherited in some settings. Studies have reported associations between common genetic variants and BPD in preterm infants. Recent genomic studies have highlighted a potential role for molecular pathways involved in inflammation and lung development in affected infants. Rare mutations in genes encoding the lipid transporter ATP-binding cassette, sub-family A, member 3 (ABCA3 gene) which is involved in surfactant synthesis in alveolar type II cells, as well as surfactant protein B (SFTPB) and C (SFTPC) can also result in severe form of neonatal-onset interstitial lung diseases and may also potentially affect the course of BPD. This chapter summarizes the current state of knowledge on the genetics of BPD.

Multiomics endotyping of preterm infants with bronchopulmonary dysplasia and pulmonary hypertension-A pilot study

Pulmonary hypertension associated with bronchopulmonary dysplasia is a severe complication of preterm birth resulting in high mortality of up to 50% within the first 2 years of life. There is a direct relationship between bronchopulmonary dysplasia severity and incidence of associated pulmonary hypertension. However, it is challenging to clinically characterize severe bronchopulmonary dysplasia with and without pulmonary hypertension and there is need for better understanding of the two entities. Our main objective is to identify markers to help understand biological processes and characterize infants with pulmonary hypertension associated with bronchopulmonary dysplasia using tracheal aspirates. We conducted an unbiased multiomic analysis of tracheal aspirates via microRNA (miRNA) polymerase chain reaction arrays, RNA sequencing, and mass spectrometry proteomics in preterm infants with severe bronchopulmonary dysplasia with and without pulmonary hypertension (n = 46). Our pilot study analysis revealed 12 miRNAs (hsa-miR-29a, has-miR-542-3p, has-miR-624, has-miR-183, hsa-miR-501-3p, hsa-miR-101, hsa-miR-3131, hsa-miR-3683, hsa-miR-3193, hsa-miR-3672, hsa-miR-3128, and hsa-miR-1287), 6 transcripts (IL6, RPL35P5, HSD3B7, RNA5SP215, OR2A1-AS1, and RNVU1-19), and 5 proteins (CAPS, AAT, KRT5, SFTPB, and LGALS3BP) with significant differential expression in preterm infants with severe lung disease with pulmonary hypertension when compared with infants with severe lung disease but no pulmonary hypertension. Pathway analysis of the integrated multiomic expression signatures revealed NFkB, VEGF, SERPINA1, IL6, and ERK1/2 as target molecules and cellular development, cellular growth and proliferation, and cellular movement as key affected molecular functions. Our multiomic analysis of tracheal aspirates revealed a comprehensive thumbprint of miRNAs, mRNAs, and proteins that could help endotype infants with severe lung disease and pulmonary hypertension.

The association between surfactant protein B gene variation and bronchopulmonary dysplasia in Chinese premature newborns

OBJECTIVE

This study aimed to correlate the pulmonary surfactant B (SP-B) gene variation with bronchopulmonary dysplasia (BPD) in ethnic Han, Chinese, premature newborns.

METHOD

47 newborns with BPD and 55 controls without BPD were included. Genomic DNA was extracted from cord or artery blood. Genotyping for the SP-B gene was performed by polymerase chain reaction or gene sequencing, and the clinical characteristics were also analyzed.

RESULTS

Two types of SP-B gene variations in Exon 2 or Exon 5 were discovered, including V1 (Exon 2: c.[5A > C] + [5A > C] or c.[5A > C] + [=]) and V2 (Exon 5: c.[428C > T] + [428C > T] or c.[428C > T] + [=]). In the BPD group, there were 33 newborns with gene variations, of which type V1 and V2 accounted for 18 and 15 respectively. In the control group, there were 19 newborns with gene variations, of which type V1 and V2 accounted for 7 and 12 respectively. There was a significant difference between the two groups in type V1 variation (X²=8.956, P < 0.05), and V1 variation was more likely associated with BPD occurrence. Logistic regression analysis showed that gene variation, premature rupture of membranes, birth weight, and the duration of mechanical ventilation were associated with BPD development. Among them, gene variation and premature rupture of the membranes were risk factors for BPD development.

CONCLUSIONS

The exon 2 or 5 of SP-B gene variations were associated with the BPD in Chinese premature newborns, and the type V1: Exon 2: c.[5A > C] + [5A > C] or c.[5A > C] + [=] was a risk factor for the development of BPD.

Genetic predisposition to bronchopulmonary dysplasia

The objective of this study is to review the candidate gene and genome-wide association studies relevant to bronchopulmonary dysplasia, and to discuss the emerging understanding of the complexities involved in genetic predisposition to bronchopulmonary dysplasia and its outcomes. Genetic factors contribute much of the variance in risk for BPD. Studies to date evaluating single or a few candidate genes have not been successful in yielding results that are replicated in GWAS, perhaps due to more stringent p-value thresholds. GWAS studies have identified only a single gene (SPOCK2) at genome-wide significance in a European White and African cohort, which was not replicated in two North American studies. Pathway gene-set analysis in a North American cohort confirmed involvement of known pathways of lung development and repair (e.g., CD44 and phosphorus oxygen lyase activity) and indicated novel molecules and pathways (e.g., adenosine deaminase and targets of miR-219) involved in genetic predisposition to BPD. The genetic basis of severe BPD is different from that of mild/moderate BPD, and the variants/pathways associated with BPD vary by race/ethnicity. A pilot study of whole exome sequencing identified hundreds of genes of interest, and indicated the overall feasibility as well as complexity of this approach. Better phenotyping of BPD by severity and pathophysiology, and careful analysis of race/ethnicity is required to gain a better understanding of the genetic basis of BPD. Future translational studies are required for the identification of potential genetic predispositions (rare variants and dysregulated pathways) by next-generation sequencing methods in individual infants (personalized genomics).