Nephronectin is required to maintain right lung lobar separation during embryonic development

Nephronectin (NPNT) is a basement membrane (BM) protein and high-affinity ligand of integrin α8β1 that is required for kidney morphogenesis in mice. In the lung, NPNT also localizes to BMs, but its potential role in pulmonary development has not been investigated. Mice with a floxed Npnt allele were used to generate global knockouts (KOs). Staged embryos were obtained by timed matings of heterozygotes and lungs were isolated for analysis. Although primary and secondary lung bud formation was normal in KO embryos, fusion of right lung lobes, primarily the medial and caudal, was first detected at E13.5 and persisted into adulthood. The lung parenchyma of KO mice was indistinguishable from wild-type (WT) and lobe fusion did not alter respiratory mechanics in adult KO mice. Interrogation of an existing single-cell RNA-seq atlas of embryonic and adult mouse lungs identified Npnt transcripts in mesothelial cells at E12.5 and into the early postnatal period, but not in adult lungs. KO embryonic lungs exhibited increased expression of laminin α5 and deposition of collagen IV in the mesothelial BM, accompanied by abnormalities in collagen fibrils in the adjacent stroma. Cranial and accessory lobes extracted from KO embryonic lungs fused ex vivo when cultured in juxtaposition, with the area of fusion showing loss of the mesothelial marker Wilms tumor 1. Because a similar pattern of lobe fusion was previously observed in integrin α8 KO embryos, our results suggest that NPNT signaling through integrin α8, likely in the visceral pleura, maintains right lung lobe separation during embryogenesis. </jats:p

Suppl FigS3_Transmission electron microscopy of embryonic lungs

Analysis of the visceral pleura in a WT and nephronectin KO lung at E16.5 by transmission electron microscopy</p

Suppl FigS1_Breeding scheme to generate KO

Generation of mice with the nephronectin null allele using a Pdgfrb-Cre transgenic </p

Suppl FigS2_scRNA-seq for nephronectin.pdf

scRNA-seq results showing cell types that express nephronectin during early postnatal period in mouse development<br

Pulmonary hypertension: An unexplored risk factor for stroke in patients with atrial fibrillation.

BACKGROUND: Atrial fibrillation (Afib) is one of the most common and significant risk factors for stroke, with the CHADsVAsc score used as the tool for stroke risk assessment. Pulmonary hypertension (PH) has not been studied as an independent risk factor for stroke in individuals with Afib. METHODS: In this retrospective case-control study, National Inpatient Sample Database was used to sample individuals with atrial fibrillation, and baseline demographics and comorbidities were collected using ICD-10 codes. Patients with missing data, age under 18, history of thromboembolic diseases, or stroke were excluded. Greedy propensity matching using R was performed to match patients with and without PH on age, race, gender, and 19 other comorbidities, including anticoagulation use. Binary logistic regression was performed after matching to assess whether PH was an independent risk factor for stroke. A p-value of \u3c 0.05 was considered statistically significant. RESULTS: Of the 2,421,545 patients included in the study, 158,545 (6.5%) had PH. PH patients were more likely to be elderly, females, and smokers. Comorbidities were more common in the PH group. Patients with PH were more likely to have an ischemic stroke (3.6% vs. 2.9%, p\u3c 0.001), hemorrhagic stroke (2.2% vs. 0.7%, p\u3c 0.001), and transient ischemic attack (TIA) (2.3% vs. 0.7%, p\u3c 0.001). After matching, the presence of PH was associated with increased ischemic stroke (OR: 1.2 [1.1-1.2]; p\u3c 0.001), hemorrhagic stroke (OR: 2.4 [2.1-2.6]; p\u3c 0.001) and TIA (OR: 2.2 [2.0-2.4]; p\u3c 0.001). PH patients also had increased length of stay (β = 0.8; p\u3c 0.001) mortality (OR: 1.1 [1.0-1.2]; p\u3c 0.001). CONCLUSION: Apart from demonstrating the deleterious effect of PH on mortality and length of hospital stay, this study is the first to report on such a large scale that PH independently increases the incidence of all types of strokes in patients with Afib