Biology subjects

Nyunoya, T.

Publications and source records attributed to Nyunoya, T..

3 recordsLinked to original sources

bioRxiv2026

A Time-Resolved Single-Cell Atlas Reveals Infection-Status, Age-, and Sex-Dependent Immune Responses Drive Viral Disease Severity

The majority of mortality during viral infections occurs in older males; however, underlying mechanisms by which age and sex shape antiviral immunity and pathological inflammatory responses remain incompletely understood. Here, we performed time-resolved single-cell RNA sequencing across 16 conditions spanning age, sex, and four stages of influenza infection in mice, generating a high-resolution atlas. Aged mice demonstrate delayed antiviral and inflammatory responses in multiple myeloid cells, impairing viral clearance, which delays recovery. Similarly, endothelial cells from aging mice show prolonged inflammatory and antiviral gene signatures. Altered gene signatures in immune and endothelial cells result in a shift in endothelial-immune interactions in the aged lung. Further, the infection status of the cell is a major driver of transcriptional state, with infected myeloid cells exhibiting broad upregulation of genes, including interferon-stimulated, inflammatory, complement, and oxidative stress-related genes. To assess whether these age-associated transcriptional patterns are conserved in humans, we examined BAL cells obtained from healthy individuals and COVID-19 patients, and found that immune cells from aged COVID-19 patients had elevated antiviral and pro-inflammatory gene expression compared to cells from young patients. Our analyses of sex differences identified that multiple myeloid cell types in aged male mice, but not in young male mice, show persistent inflammatory responses at later stages of infection, a likely mechanism contributing to elevated mortality in older males. These data reveal how infection status of the cell, age, and sex interact to drive persistent inflammation and impaired resolution, providing a foundational resource for designing age- and sex-specific therapeutic strategies.

immunology↗

bioRxiv2026

Epithelial QKI Protects Against Emphysema by Maintaining Mitochondrial Integrity

Single-cell transcriptomic profiling of chronic obstructive pulmonary disease (COPD) lungs identified QKI, an RNA-binding protein, as a candidate emphysema-associated gene, but its epithelial role in COPD pathobiology remains unclear. We show that QKI expression is reduced in human COPD lungs and that alveolar type 2 epithelial (AT2) cell QKI protein levels correlate strongly with spirometric indices and diffusing capacity (DLCO). Lung epithelium-specific QKI knockout mice (QKI{Delta}/{Delta}) developed spontaneous airspace enlargement with emphysema-like mechanics, and QKI-deficient AT2 cells showed impaired spheroid colony formation and increased apoptosis. Integrated transcriptomic and proteomic analyses of primary AT2 cells revealed a selective reduction in functional mitochondrial (respiratory-chain and metabolic) protein abundance despite relatively preserved transcript levels, consistent with mitochondrial transcriptome-proteome discordance. QKI loss increased mtDNA abundance and TOMM20 staining but decreased ATP5A, indicating accumulation of structurally increased but functionally dysfunctional mitochondria. In human epithelial cells, CRISPR-mediated QKI deficiency reduced oxidative respiration, increased glycolytic reliance, elevated mitochondrial ROS and membrane potential, and increased apoptosis; these phenotypes were partially rescued by QKI re-expression. These findings identify epithelial QKI as a regulator of mitochondrial integrity and stress tolerance in COPD.

cell biology↗

bioRxiv2025

Reciprocal Regulation Between the SCFFBXO24 Ubiquitin E3 Ligase and FoxP1 Protein

Forkhead Box Protein P1 (FoxP1) is a crucial transcriptional repressor essential for the development of the brain and heart. In adults, FoxP1 protein levels are dysregulated in a variety of disorders, including chronic obstructive pulmonary disease (COPD), atherosclerosis, and heart failure, where they causally contribute to disease pathogenesis. Although independent investigators have reported that FoxP1 protein is ubiquitinated, and E3 ligases have been identified for other FoxP family proteins, the identity of the E3 ligase that controls FoxP1 protein stability has remained unknown. Here, we identify FBXO24, a subunit of the Skp-Cullin-F-box (SCF) ubiquitin E3 ligase complex, as the regulator of FoxP1 ubiquitination and stability. Specifically, FBXO24 regulates K48 and K63 ubiquitination, complexes with, and co-localizes to the nucleus with FoxP1 protein in lung epithelial cells. Depleting FBXO24 reverses the unfolded protein response and cell death triggered by loss of FoxP1 protein in lung epithelium, suggesting a protective role. Additionally, FBXO24 knockout mice exhibit elevated FoxP1 levels in the lung and heart and reduced unfolded protein response activity after short-term cigarette smoke exposure. Intriguingly, we also uncovered bidirectional regulation, whereby FoxP1 protein binds to the FBXO24 promoter to suppress FBXO24 transcription. To our knowledge, this is the first evidence that a substrate for an E3 ligase can also regulate the E3 ligase and, therefore, control levels of other substrates, revealing new regulatory networks. Targeting FBXO24 may offer a therapeutic strategy for COPD, atherosclerosis, and heart failure by stabilizing FoxP1 levels in the heart and lungs and mitigating harmful downstream effects.

molecular biology↗