Biology subjects

Hsu, P. P.

Publications and source records attributed to Hsu, P. P..

8 recordsLinked to original sources

bioRxiv2025

Clinical Interventions and Inflammatory Signaling Shape the Transcriptional and Cellular Architecture of the Early Postnatal Lung

The early postnatal period in human development is characterized by extensive remodeling of the distal lung to support gas exchange, but this critical period remains poorly understood. Here, we constructed a comprehensive cellular atlas of the early postnatal human lung (0 to 2 years) using single-nucleus RNA sequencing of histologically normal specimens from 23 individuals. Our analysis identified two previously unknown and mutually exclusive transcriptional states of alveolar type 2 (AT2) cells, one defined by upregulation of genes involved in lipid metabolism and identified by unique expression of FMO5, and the other defined by upregulation of inflammatory response genes and identified by unique expression of CFTR. Using spatial transcriptomics, we discovered that AT2 cell states reside in specific niches and interact with distinct alveolar fibroblast subtypes. Clinical data and organoid experiments further suggest that the environment dictates which state prevails as the pro-inflammatory/pro-regenerative signals TNF- and IL-1{beta} promoted the CFTR+ state in vitro, while patients treated with the anti-inflammatory drug dexamethasone (Dex) had more abundant FMO5+ AT2 cells, and Dex induced the FMO5+ state in vitro. These observations link inflammatory signaling and anti-inflammatory clinical interventions to shifts in transcriptional state of the alveolar epithelium. We benchmarked two neonatal lung diseases, bronchopulmonary dysplasia and pulmonary interstitial glycogenosis, revealing a profound disruption in the balance of AT2 states, a broad arrest of postnatal cellular development, and impaired cellular maturation. Our work uncovers a fundamental new understanding of early postnatal human lung biology, linking pro- and anti-inflammatory signaling to AT2 transcriptional phenotypes and providing a new framework for understanding lung disease.

developmental biology↗

bioRxiv2025

Intraoperative arteriovenous patient sampling to assess in situ non-small cell lung cancer metabolism

We performed intraoperative arteriovenous sampling in participants undergoing surgical resection for non-small cell lung cancer (NSCLC) to characterize in situ tumor metabolism, directly measuring metabolite consumption and secretion in tumor-bearing lung versus normal lung and the systemic circulation. Healthy lung tissue secreted lower levels of lactate, pyruvate, and tricarboxylic acid (TCA) intermediates and consumed less glucose compared to the systemic circulation. In contrast, tumor-bearing lung demonstrated elevated lactate secretion, along with increased efflux of succinate, fumarate, glycine, and aspartate, despite similar glucose uptake. Lactate secretion correlated with tumor PET avidity but not size, and overall metabolic profiles distinguished cancerous from normal lung tissue. These findings confirm enhanced glycolysis in NSCLC in vivo, while also revealing context-dependent patterns of TCA metabolite accumulation and amino acid secretion. Our results demonstrate the utility of intraoperative sampling to uncover metabolic features of human tumors.

cancer biology↗

bioRxiv2025

Labile iron pool dynamics do not drive ferroptosis potentiation in colorectal cancer cells

Colorectal cancer (CRC) is the second leading cause of cancer-related mortality in the United States. CRC tumors exhibit aberrant iron accumulation, which supports tumor cell proliferation through multiple metabolic pathways. However, the oncogenic benefits of elevated iron must be counterbalanced by its potential to catalyze oxidative damage via reactive oxygen species generated from labile, redox-active iron. Ferroptosis is a regulated, non-apoptotic form of cell death characterized by iron-dependent lipid peroxidation. This process is tightly controlled by the selenoenzyme glutathione peroxidase 4 (GPX4), which reduces lipid peroxides and can be pharmacologically inhibited by agents such as RSL3 and JKE1674. A key source of redox-active iron is the labile iron pool (LIP), yet its role in regulating ferroptosis remains incompletely defined. To examine this, we supplemented CRC cells with exogenous iron following pharmacologic induction of ferroptosis. Iron supplementation significantly reduced cell viability, suggesting that expansion of the LIP potentiates ferroptotic cell death. However, whether ferroptosis is accompanied by dynamic changes in the LIP, and if such changes are mechanistically required for its potentiation, were unknown. To further characterize this response, we profiled the expression of iron regulatory genes under ferroptotic conditions and observed no change in transcriptional response in iron homeostasis genes. Using a reactivity-based probe of labile iron, we found that the LIP did not measurably increase during ferroptosis induction with GPX4 inhibition or inhibition of the SLC7A11 cysteine/glutamate antiporter. These findings suggest that the LIP does not expand upon pharmacological initiated ferroptosis, despite the potentiating effect of exogenous iron supplementation.

cancer biology↗

bioRxiv2024

A spatially-resolved blueprint of the developing human lung reveals a basal cell population regulated by a WNT-driven niche

Organs are composed of diverse cell types that change across space and time during development. To interrogate this diversity, we micro-dissected developing human lungs along the proximal-distal axis during the late pseudoglandular stage and generated an integrated analysis of single-nucleus sequencing and spatial transcriptomics, creating a cellularly-resolved atlas of the lung. These rich datasets revealed positional niches and cellular heterogeneity along the proximal-distal axis, including the identification of a unique population of TP63+ basal cells, the primary stem cell of the airway, marked by expression of LGR5 and LGR6. Analysis of the LGR5+ basal cell niche and functional experiments with primary organoid models suggest a tonic level of WNT pathway activity in LGR5+ basal cells that is potentiated by mesenchyme-derived R-SPONDIN. We found that basal cell self-renewal is enhanced by WNT activity, suggesting that the WNT pathway plays a previously unappreciated but critical role in airway stem cell maintenance during human development. These results enhance our fundamental understanding of the positional and cellular heterogeneity in the developing human lungs and begin to reveal unique niches that maintain homeostasis throughout the lung.

developmental biology↗

bioRxiv2023

Opposing roles for TGFbeta and BMP-signaling during nascent alveolar differentiation in the developing human lung

Alveolar type 2 (AT2) cells function as stem cells in the adult lung and aid in repair after injury. The current study aimed to understand the signaling events that control differentiation of this therapeutically relevant cell type during human development. Using lung explant and organoid models, we identified opposing effects of TGF{beta}- and BMP-signaling, where inhibition of TGF{beta}- and activation of BMP-signaling in the context of high WNT- and FGF-signaling efficiently differentiated early lung progenitors into AT2-like cells in vitro. AT2-like cells differentiated in this manner exhibit surfactant processing and secretion capabilities, and long-term commitment to a mature AT2 phenotype when expanded in media optimized for primary AT2 culture. Comparing AT2-like cells differentiated with TGF{beta}-inhibition and BMP-activation to alternative differentiation approaches revealed improved specificity to the AT2 lineage and reduced off-target cell types. These findings reveal opposing roles for TGF{beta}- and BMP-signaling in AT2 differentiation and provide a new strategy to generate a therapeutically relevant cell type in vitro.

developmental biology↗

bioRxiv2023

Screening in serum-derived medium reveals differential response to compounds targeting metabolism

INTRODUCTION INTRODUCTION RESULTS DISCUSSION KEY RESOURCES TABLE CONTACT FOR REAGENT AND... EXPERIMENTAL MODEL AND SUBJECT... METHOD DETAILS QUANTIFICATION AND STATISTICAL... Data resources DATA AND SOFTWARE AVAILABILITY AUTHOR CONTRIBUTIONS DECLARATION OF INTERESTS REFERENCES Studies of cancer cells in standard culture conditions have long been used as a tractable tool for drug discovery. Cell culture provides unparalleled experimental flexibility, scalability, and low cost to identify and understand the response to cancer therapeutics; however, drug responses in culture are not always predictive of drug response in animal models or in patients1 ...

cancer biology↗

bioRxiv2022

Nucleotide depletion promotes cell fate transitions by inducing DNA replication stress

Control of cellular identity requires coordination of developmental programs with environmental factors such as nutrient availability, suggesting that modulating aspects of metabolism could alter cell state along differentiation trajectories. Here we find that nucleotide depletion and DNA replication stress are common drivers of cell state progression across a variety of normal and transformed hematopoietic systems. DNA replication stress-induced cell state transitions begin during S phase and are independent of ATR/ATM checkpoint signaling, double-stranded DNA break formation, and changes in cell cycle length. In systems where differentiation is blocked by oncogenic transcription factor expression, replication stress leads to increased activity at primed regulatory loci and expression of lineage-appropriate maturation genes while progenitor TF activity is still present. Altering the baseline cell state by manipulating the cohort of transcription factors expressed redirects the effect of replication stress towards induction of a different set of lineage-specific genes. The ability of replication stress to selectively activate primed maturation programs across different cellular contexts suggests a general mechanism by which metabolism can promote lineage-appropriate and potentially therapeutically relevant cell state transitions.

cancer biology↗

bioRxiv2022

Distinct airway progenitor cells drive epithelial heterogeneity in the developing human lung

Recent advances using single cell genomic approaches have identified new epithelial cell types and uncovered cellular heterogeneity in the murine and human lung (1). Here, using scRNA-seq and microscopy we identify and describe a secretory-like cell that is enriched in the small airways of the developing human lung and identified by the unique co-expression of SCGB3A2/SFTPB/CFTR. To place these cells in the hierarchy of airway development, we apply a single cell barcode-based lineage tracing method track the fate of SCGB3A2/SFTPB/CFTR cells during airway organoid differentiation in vitro (2). Lineage tracing revealed that these cells have distinct developmental potential from basal cells, giving rise predominantly to pulmonary neuroendocrine cells (PNECs) and a subset of multiciliated cells distinguished by high C6 and low MUC16 expression. We conclude that SCGB3A2/SFTPB/CFTR cells act as a progenitor cell contributing to the cellular diversity and heterogeneity in the developing human airway. SIGNIFICANCE STATEMENTThe current study identifies a novel secretory cell type that is present predominantly in the small airway of the developing human lung. These secretory cells are defined by co-expression of SCGB3A2/SFTPB/CFTR, and functional studies show that this cell gives rise to pulmonary neuroendocrine cells and a sub-population of multiciliated cells, thereby leading to cellular heterogeneity.

developmental biology↗