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Mallapragada, S.

Publications and source records attributed to Mallapragada, S..

3 recordsLinked to original sources

Fishing with Two Lines: A Hybrid Approach to Spatial Transcriptomic Discovery

Spatial transcriptomics faces a trade-off between the number of genes assayed and depth of per-gene sensitivity. We developed a dual chemistry method that combines the high sensitivity of a 10X Genomics Xenium V1 custom panel (up to 480 genes) with the broad coverage of the Prime 5K panel (5001 genes) on a single tissue section. This involved co-hybridizing Prime and V1 probes and sequentially running the V1 and Prime decoding chemistries. Applied to a human lung tissue microarray, we observed high concordance between the V1 and Prime chemistries when run independently (on serial sections) and the dual chemistry runs. Overlapping genes (profiled on both V1 and Prime chemistries) showed similar expression patterns in the dual run demonstrating the fidelity of the assay. By combining information from both the V1 and Prime chemistries within the same cell, we retain more cells, gain valuable additional information, and enable both high sensitivity profiling and discovery.

molecular biology↗

A spatial transcriptomic atlas of acute neonatal lung injury across development and disease severity

A molecular understanding of lung organogenesis requires delineation of the timing and regulation of the cellular transitions that ultimately form and support a surface capable of gas exchange. While the advent of single-cell transcriptomics has allowed for the discovery and identification of transcriptionally distinct cell populations present during lung development, the spatiotemporal dynamics of these transcriptional shifts remain undefined. With imaging-based spatial transcriptomics, we analyzed the gene expression patterns in 17 human infant lungs at varying stages of development and injury, creating a spatial transcriptomic atlas of [~]1.2 million cells. We applied computational clustering approaches to identify shared molecular patterns among this cohort, informing how tissue architecture and molecular spatial relationships are coordinated during development and disrupted in disease. Recognizing that all preterm birth represents an injury to the developing lung, we created a simplified classification scheme that relies upon the routinely collected objective measures of gestational age and life span. Within this framework, we have identified cell type patterns across gestational age and life span variables that would likely be overlooked when using the conventional "disease vs. control" binary comparison. Together, these data represent an open resource for the lung research community, supporting discovery-based inquiry and identification of targetable molecular mechanisms in both normal and arrested human lung development.

genomics↗

Bronchopulmonary Dysplasia with Pulmonary Hypertension Associates with Loss of Semaphorin Signaling and Functional Decrease in FOXF1 Expression

Lung injury in preterm infants leads to structural and functional respiratory deficits, with a risk for bronchopulmonary dysplasia (BPD) that in its most severe form is accompanied by pulmonary hypertension (PH). To examine cellular and molecular dynamics driving evolving BPD in humans, we performed single-cell RNA sequencing of preterm infant lungs in early stages of BPD and BPD+PH compared to term infants. Analysis of the endothelium revealed a unique aberrant capillary cell-state primarily in BPD+PH marked by ANKRD1 expression. Predictive signaling analysis identified deficits in the semaphorin guidance-cue signaling pathway and decreased expression of pro-angiogenic transcription factor FOXF1 within the alveolar parenchyma in neonatal lung samples with BPD/BPD+PH. Loss of semaphorin signaling was replicated in a murine BPD model and in humans with alveolar capillary dysplasia (ACDMPV), suggesting a mechanistic link between the developmental programs underlying BPD and ACDMPV and a critical role for semaphorin signaling in normal lung development.

genomics↗