Biology subjects

Kliment, C.

Publications and source records attributed to Kliment, C..

4 recordsLinked to original sources

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↗

bioRxiv2026

Identification of smoking-enabled blood miRNA regulatory networks

Cigarette smoking induces complex signaling disruptions that contribute to diseases such as COPD and lung cancer, yet the molecular mechanisms underlying these effects remain incompletely understood. To address this gap, we analyzed peripheral blood from 3190 COPDGene participants using LIONESS and PUMA and constructed miRNA-mRNA regulatory networks associated with smoking status. Comparing networks for active versus former smokers uncovered a striking shift in regulatory architecture: active smokers exhibited elevated miRNA targeting of the mitochondrial complex I protein NDUFA12. This finding was validated in lung tissue expression data from the Lung Genomics Research Consortium (LGRC), where we observed that ever-smokers showed consistent dysregulation of Ndufa12-targeting miRNAs compared to never-smokers. This allowed us to identify a set of smoking-defined circulating and tissue-associated miRNAs. To investigate the specific cellular compartment, we analyzed cell-type deconvoluted expression data from COPDGene blood and LTRC (Lung Tissue Research Consortium) lung tissue, as well as lung transcriptomics data from cigarette smoke-exposed mice, and identified the monocyte/macrophage compartment as a principal site of NDUFA12/Ndufa12 expression. Human THP-1 macrophages treated with cigarette smoke extract demonstrated selective inhibition of NDUFA12 by network-defined miRNAs. These distinct, NDUFA12-targeting, smoking-associated miRNA signatures, revealed through network analysis, describe new smoking-mitochondrial interactions that may serve as novel targets for therapeutic intervention.

Molecular Biology↗

bioRxiv2022

Loss of ANT1 Increases Fibrosis and Epithelial Cell Senescence in Idiopathic Pulmonary Fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is an interstitial lung disease characterized by progressive lung scarring and remodeling. Although treatments exist that slow disease progression, IPF is irreversible and there is no cure. Cellular senescence, a major hallmark of aging, has been implicated in IPF pathogenesis, and mitochondrial dysfunction is increasingly recognized as a driver of senescence. Adenine nucleotide translocases (ANTs) are abundant mitochondrial ATP-ADP transporters critical for regulating cell fate and maintaining mitochondrial function. We sought to determine how alterations in ANTs influence cellular senescence in pulmonary fibrosis. We found SLC25A4 (ANT1) and SLC25A5 (ANT2) expression is reduced in the lungs of IPF patients and particularly within alveolar type II cells by single cell RNA sequencing. Loss of ANT1 by siRNA in lung epithelial cell lines resulted in increased senescence markers such as beta-galactosidase staining and p21 by Western Blot and RT-qPCR. Bleomycin treated ANT1 knockdown cells also had increased senescence markers when compared to bleomycin treated control cells. Global loss of ANT1 resulted in worse lung fibrosis and increased senescence in the bleomycin and asbestos-induced mouse models of pulmonary fibrosis. This data supports the concept that loss of ANT1 drives IPF pathogenesis through mitochondrial dysfunction associated cellular senescence (MiDaS). In summary, loss of ANT1 induces cellular senescence, leading to abnormal tissue remodeling and enhanced lung fibrosis in IPF. Modulation of ANTs presents a new therapeutic avenue that may alter cellular senescence pathways and limit pulmonary fibrosis.

cell biology↗

bioRxiv2020

Adenine Nucleotide Translocase regulates the airway epithelium, mitochondrial metabolism and ciliary function

Airway hydration and ciliary function are critical to airway homeostasis and dysregulated in chronic obstructive lung disease (COPD). COPD is the 4th leading cause of death in the US and is impacted by cigarette smoking with no therapeutic options. We utilized a genetic selection approach in the amoeba Dictyostelium discoideum as a comparative discovery tool in lung biology to identify genetic protectors from cigarette smoke (CS). Adenine nucleotide translocase (ANT), a mitochondrial ADP/ATP transporter, was protective against CS in Dictyostelium and human bronchial epithelial cells. ANT2 gene expression is reduced in lung tissue from COPD patients and in a mouse smoking model. ANT1 and ANT2 overexpression resulted in enhanced oxidative respiration and ATP flux. In addition to ANTs presence in the mitochondria, ANT1 and ANT2 reside at the plasma membrane in airway epithelial cells and this localization plays a role in how ANTs regulate airway homeostasis. ANT2 overexpression stimulates airway surface liquid hydration by ATP and maintains ciliary beating after CS exposure, which are key functions of the airway. Our study highlights the potential of ANT modulation in protecting from dysfunctional mitochondrial metabolism, airway hydration, and ciliary motility in COPD.

cell biology↗