Search Results (146)

Pulmonary fibrosis (PF) is a progressive lung condition characterized by irreversible scarring and high mortality, with limited effective treatments. Mitochondrial dysfunction has emerged as a critical factor in fibroblast activation in PF, although approaches to restore mitochondrial function remain underexplored. The present study investigated whether mitochondrial transfer from alveolar type II epithelial cells (A549) to patient-derived fibroblasts could restore mitochondrial function and bioenergetics. Histological analysis of fibrotic lungs reveals increased collagen deposition and elevated profibrotic markers, accompanied by reduced expression of mitochondrial biogenesis and respiratory proteins compared to non-fibrotic controls, indicating mitochondrial impairment. Freshly isolated donor mitochondria were functionally validated before mitoception using Seahorse analysis and patient-derived fibroblasts were confirmed by qRT-PCR using fibroblast-specific markers. In vitro transfer of mitochondria to diseased patient-derived fibroblasts exhibited a modest, dose and time-dependent increase in mitochondrial membrane potential compared to normal fibroblasts. Gene expression analysis revealed decreased fibrosis-associated markers and increased expression of mitochondrial and antioxidant genes following mitoception. Seahorse analysis after mitoception revealed enhanced ATP-linked respiration and improved selected mitochondrial bioenergetic parameters, whereas maximal respiration and spare respiratory capacity demonstrated variable responses. In contrast, normal fibroblasts displayed minimal changes. Collectively, these findings indicate that mitochondrial transfer modulates fibroblast bioenergetics and profibrotic signaling, supporting its potential as a therapeutic strategy for pulmonary fibrosis. Full article

Yaks (Bos grunniens) are large mammals endemic to the Qinghai–Tibet Plateau. Efficient lung development is crucial for their adaptation to high-altitude hypoxia. As progenitor cells of the alveoli, type II alveolar epithelial (AT2) cells warrant further investigation into their physiological functions; however, relevant studies remain limited. In this study, primary AT2 cells were isolated from the lungs of yaks. Concurrently, lung tissues were collected from yaks at distinct developmental stages to investigate the role of the EGF/EGFR axis in regulating AT2 cell proliferation and apoptosis, as well as its essential contribution to yak lung development. Here, we demonstrate that the EGF/EGFR axis plays a beneficial role in yak alveolar development. Exogenous EGF supplementation or EGFR activation upregulated the downstream factors AKT and STAT3, enhanced AT2 cell proliferation, and reduced apoptosis. In contrast, EGFR inhibition promoted AT2 cell apoptosis and suppressed proliferation. Cell cycle analysis revealed that both exogenous EGF and EGFR activation increased the proportion of AT2 cells in the S and G2 phases, whereas EGFR inhibition caused cell cycle arrest at the G0/G1 phase. Moreover, the expression of cell cycle regulators cyclin D1, CDK4, and CDK6 was upregulated, while p16 and p21 expression was downregulated. Further comparative analyses indicated that the EGF/EGFR axis positively contributes to alveolar development in juvenile yaks. Collectively, these findings confirm that in plateau environments, activation of the EGF/EGFR axis promotes AT2 cell proliferation and inhibits apoptosis, thereby facilitating alveolar development in juvenile yaks. A key limitation is the lack of parallel comparisons with low-altitude cattle and other plateau-endemic species (e.g., Tibetan sheep), which precludes definitive assessment of the specificity of the EGFR/EGF axis in yak AT2 cell proliferation and lung development. Full article

Background/Objectives: Exposure to particulate matter (PM) containing bacterial endotoxins triggers inflammation and oxidative stress in the respiratory epithelium. In this study, we investigated chitosan nanoparticle-loaded Cordyceps militaris grown on germinated Rhynchosia nulubilis (GCN) as a potential functional food-derived ingredient against PM- and lipopolysaccharide (LPS)-induced cellular damage in human lung epithelial cells. Methods: This study employed an integrative approach combining GCN analysis with bioinformatics methods using a PM- and LPS-induced pulmonary cellular inflammation model. Gene Expression Omnibus (GEO) transcriptomic datasets and Cytoscape-based network analysis were utilized to identify key hub genes and signaling pathways associated with PM- and LPS-induced pulmonary inflammation, which were subsequently validated by RT-PCR and Western blotting. Results: Nano-encapsulation significantly improved the antioxidant capacity and storage stability of the extract compared with non-encapsulated Cordyceps militaris grown on germinated Rhynchosia nulubilis (GRC). GCN markedly attenuated PM- and LPS-induced cytotoxicity and intracellular reactive oxygen species (ROS) production in a dose-dependent manner, resulting in a therapeutic index approximately 4.5-fold higher than that of GRC under PM and LPS co-exposure. Bioinformatics analysis identified inflammation-related genes and pathways associated with PM- and LPS-induced pulmonary responses, primarily enriched in tumor necrosis factor (TNF)-related inflammatory pathways, Toll-like receptor signaling, and cytokine signaling. Consistent with these findings, GCN suppressed the expression of C-X-C motif chemokine ligand 2 (CXCL-2) and tumor necrosis factor-alpha (TNF-α) mRNA and inhibited mitogen-activated protein kinase (MAPK)-mediated activator protein-1 (AP-1) and nuclear factor-kappa B (NF-κB) signaling pathways in human type II alveolar epithelial cells (A549). Conclusions: Collectively, nano-encapsulation enhanced the stability and bioactivity of Cordyceps militaris-based extracts, suggesting that GCN may have potential as a functional food-derived candidate ingredient to protect airway epithelial cells against inflammation and oxidative stress induced by PM and LPS. As this study was conducted using an in vitro A549 epithelial cell model, further validation in physiologically relevant systems is needed to confirm its translational applicability. Full article

Background and Objectives: Surfactant protein B (SFTPB) is a surfactant-associated protein secreted by alveolar type II epithelial cells that plays a critical role in maintaining alveolar stability and surface tension. Although SFTPB is closely associated with pulmonary epithelial differentiation, its clinical significance in different non-small cell lung cancer (NSCLC) subtypes remains unclear. This study investigated the clinicopathologic and prognostic significance of SFTPB expression in lung adenocarcinoma (AD) and lung squamous cell carcinoma (SCC) using The Cancer Genome Atlas (TCGA) dataset. Materials and Methods: SFTPB mRNA expression data and clinicopathologic information were obtained from TCGA cohorts of AD and SCC patients. Patients were stratified into high- and low-expression groups according to median SFTPB expression levels. Associations between SFTPB expression and clinicopathologic variables were analyzed, and correlation analyses were performed with major oncogenic genes. Overall survival (OS) and relapse-free survival (RFS) were evaluated using Kaplan–Meier survival analysis and log-rank testing. Multivariate Cox proportional hazards regression analyses were performed after adjustment for age, sex, and pathological stage. Results: In AD, high SFTPB expression was significantly associated with lower pathologic stage (p = 0.011) and lower N stage (p = 0.006). SFTPB expression showed significant negative correlations with EGFR (R = −0.140, p = 0.002) and BRAF (R = −0.177, p < 0.001) and a positive correlation with TP53 (R = 0.128, p = 0.004). Patients with high SFTPB expression demonstrated significantly improved OS compared with those with low expression (p < 0.001), while a trend toward prolonged RFS was observed without statistical significance (p = 0.089). Multivariate analysis confirmed high SFTPB expression as an independent favorable prognostic factor in AD (HR = 0.551, 95% CI = 0.405–0.748, p < 0.001). In SCC, high SFTPB expression was also significantly associated with lower pathologic stage (p = 0.009) and lower N stage (p = 0.007). SFTPB expression showed significant negative correlations with SOX2 (R = −0.176, p < 0.001), PIK3CA (R = −0.143, p = 0.002), and TP53 (R = −0.101, p = 0.026). In contrast to AD, high SFTPB expression was significantly associated with poorer OS (p = 0.026), whereas no significant difference in RFS was observed (p = 0.307). Multivariate analysis demonstrated that high SFTPB expression was an independent adverse prognostic factor in SCC (HR = 1.347, 95% CI = 1.028–1.767, p = 0.031). Conclusions: SFTPB expression is significantly associated with clinicopathologic characteristics and molecular signatures in both AD and SCC. However, its prognostic implications differ according to histologic subtype. High SFTPB expression independently predicts favorable survival in AD but unfavorable survival in SCC, suggesting distinct lineage-specific biological roles in NSCLC. These findings support SFTPB as a subtype-specific prognostic biomarker reflecting differential differentiation states and lineage context in NSCLC. Full article

Background: Small cell lung cancer (SCLC) carries a dismal prognosis with limited biomarkers for risk stratification. This study aimed to identify circulating prognostic biomarkers. Methods: We prioritized SCLC risk-associated genes using Summary-data-based Mendelian Randomization of pQTL/eQTL, differential expression, and weighted gene co-expression network analysis. Five machine learning approaches were compared to develop a diagnostic model based on ACE, AGER, and IL18R1, trained on GSE149507 and validated in GSE60052. We conducted single-cell transcriptomic analysis using public datasets (GSE150766 and GSE279570) and peripheral blood mononuclear cells (PBMCs) from our extensive-stage cohort. Finally, prioritizing the lead candidate IL18R1, we enrolled a prospective clinical cohort to assess its prognostic utility. A LASSO–Cox prognostic model incorporating plasma IL18R1 and clinical variables was internally validated (7:3 split) for progression-free survival (PFS) prediction. Results: Integrative multi-omics identified ACE, AGER, and IL18R1 as SCLC-protective genes. Elastic Net machine learning identified a two-gene predictive signature (AGER and IL18R1) with robust diagnostic accuracy. Single-cell RNA sequencing revealed the predominant downregulation of ACE, AGER, and IL18R1 in T cells and alveolar type II cells from SCLC patients. PBMC analysis further supported IL18R1 downregulation in CD8⁺ T cells, NK cells, and dendritic cells. In an independent prospective cohort (n = 300), lower plasma IL18R1 levels were independently associated with shorter PFS (HR = 0.997 per unit increase; 95% CI: 0.995–0.999; and p = 0.003), with time-dependent AUCs of 0.77–0.86. Performance in limited-stage disease was inconsistent and requires further validation. A prognostic model incorporating plasma IL18R1 and 11 clinical parameters stratified patients into distinct risk groups (HR = 5.19), showing a strong discriminative ability in extensive-stage SCLC. Conclusions: We identified ACE, AGER, and IL18R1 as protective factors against SCLC progression. Integration of plasma IL18R1 with clinical parameters provides a prognostic tool for extensive-stage SCLC. Full article

A549 cells are widely used as an in vitro model of alveolar type II (ATII) epithelial cells; however, their phenotype and metabolic state are highly sensitive to culture conditions, cell density, and the duration of static, non-passaged cultivation. Here, we examined how prolonged static culture affects lipid metabolism, mitochondrial bioenergetics, and viability in A549 cells. A549 cultures were maintained without passaging for up to 25 days in DMEM or Ham’s F-12 and analyzed using lipid secretion assays, targeted lipidomics, [¹⁴C]-acetate incorporation, Seahorse bioenergetic profiling, and transcriptional analysis of stress-associated markers. Several surfactant-associated readouts were highest during early culture, peaking on day 7, as evidenced by elevated expression of ABCA3 and SP-A and maximal secretion of surfactant-associated phospholipids. With prolonged cultivation and increasing culture density, cellular phosphatidylglycerol levels declined progressively and became nearly undetectable by day 25, accompanied by reduced anabolic lipid metabolism, lower oxygen consumption, and impaired glycolytic activity. These changes coincided with increased reactive oxygen species, elevated intracellular Ca²⁺ levels, and increased expression of stress-associated transcripts, including CASP1, IL1B, and C3. Later stages were also associated with reduced mitochondrial respiration and decreased viability. Collectively, our findings show that prolonged static culture is associated with metabolic remodeling and reduced bioenergetic capacity in A549 cells. Full article

Background: Severe lung compromise from COVID-19, ARDS, and recently AH3N2 can progress to life-threatening hypoxia. Past experience led to standardized protocols that assumed similarity to SARS-CoV. Methods: COVID-19 pathophysiology and histopathological lung biopsy photomicrographs are analyzed. Results: Pneumolysis is defined as progressive alveolar–capillary destruction resulting from SARS-CoV-2 attack on pneumocytes. In the final stages preceding pneumolysis, molecular mechanisms in the lungs include apoptosis in alveolar epithelial type I and II cells, compromising alveolar regeneration, and necrosis, resulting in leakage of intracellular contents and amplifying inflammation. Pyroptosis, driven by inflammasome activity, further disrupts alveolar integrity in ARDS. Histopathological findings include Masson bodies, alveolar-coating cells with nuclear atypia, reactive pneumocytes and reparative fibrosis, intra-alveolar hemorrhage, moderate inflammatory infiltrates and abscesses, microthrombi, hyaline membrane remnants, and emphysema. The three theoretical pathophysiological stages of progressive hypoxemia (silent hypoxemia, gasping, and death zone) are shown. Conclusions: Silent hypoxemia rapidly progresses to critical hypoxemia. This progression results from progressive pneumolysis, inflammation, immune overexpression, autoimmunity, and HAPE-type edema, leading to acute pulmonary insufficiency. Long-lasting COVID-19 can result in fibrosis and, as a compensatory mechanism, polierythrocythemia. The proposed treatment (based on tolerance to hypoxia and the hemoglobin factor) includes prompt oxygen administration, control of inflammatory and immune responses, antibiotics, rehydration, erythropoietin and platelet aggregation inhibitors. Full article

Alveolar inflammation, elevated interleukin-17A (IL-17A), and fibrin deposition are common features in all forms of lung injury followed by fibrotic repair. Type II alveolar epithelial cell (AEC) viability, regulated by tumor suppressor protein p53 and changes in uPA-mediated fibrinolysis, has been linked to lung injury and pulmonary fibrosis (PF). Nevertheless, mechanistic details linking increased IL-17A with p53 and PAI-1 to lung injury and remodeling remain unclear. We found that IL-17A and its receptor (IL-17RA) are induced during various lung injuries. IL-17A augments IL-17RA, p53 and downstream PAI-1 with a concurrent decrease in uPA and its receptor (uPAR) in AECs. These changes promote AEC apoptosis, alveolar injury and PF. In addition, IL-17A causes a dose-dependent increase in IL-17RA and profibrogenic markers in lung fibroblasts (LFs), suggesting myofibroblast differentiation. We further found that inhibition of IL-17A by caveolin-1 scaffolding domain peptide (CSP) or its 7-mer deletion fragment (CSP7) inhibits AEC apoptosis, lung inflammation, and profibrogenic markers in LFs and PF. Further, treatment of mice with bleomycin-induced lung injury using CSP7, an anti-IL-17A antibody, or an IL-17RA blocking antibody attenuates total lung hydroxyproline and soluble collagen content, as well as levels of profibrogenic markers. These observations support the role of IL-17A/IL-17RA signaling in lung injury and post-injury remodeling. Full article

Bluetongue virus (BTV) infects various ruminant species, posing significant threats to animal health and causing substantial economic losses to the livestock industry. Ovine type II alveolar epithelial cells (OAECIIs) play crucial roles in maintaining pulmonary structural integrity and modulating immune responses. Their dysfunction is closely associated with lung disease pathogenesis, making them important therapeutic targets. However, OAECIIs’ immunoregulatory functions and early response mechanisms during BTV infection remain unclear. To address this, we analyzed transcriptomic changes in OAECIIs following BTV-1 infection. RNA-seq revealed 1047 and 852 differentially expressed genes (DEGs) at 8 and 12 h post-infection (hpi), respectively, compared to uninfected controls. Bioinformatics analysis showed significant upregulation of nucleic acid-sensing receptors, interferon-stimulating factors, inflammatory mediators, and cytokines during early infection, mediated primarily through type I interferon signaling, TNF signaling, and cytosolic DNA-sensing pathways. We identified MAD5, ZNFX1, cGAS, OAS, PKR and ZBP1 as key pattern recognition receptors in OAECIIs during BTV infection. The IFN-β, MX1/2, RSAD2 and PLSCR1 pathways mediated antiviral responses, while IL-15, CXCL10, CCL2 triggered inflammatory responses, collectively causing structural alterations through AQP1/9 and tight junction protein modulation. These findings provide critical insights into early antiviral mechanisms and cellular structural changes in OAECIIs during BTV infection, establishing a foundation for understanding pneumonia pathogenesis and developing targeted BTV therapies. Full article

The reactivation of Wnt signaling pathways plays an important role in driving myofibroblast differentiation in fibrotic diseases; however, the mechanism is not clearly understood. In this study, we investigate the role of non-canonical Wnt11 signaling in human lung fibroblasts and its contributions to myofibroblast differentiation. Our results show that components of the non-canonical Wnt pathway are upregulated in bleomycin-induced pulmonary fibrosis and that in vivo depletion of Wnt11 in mouse lung fibroblasts significantly reduces lung fibrosis. Furthermore, co-culture studies using fibroblasts and alveolar type II epithelial cells (AECII) revealed a Wnt11-mediated mechanism that promotes myofibroblast differentiation. Finally, we demonstrate that in human lung fibroblasts, TGFβ can increases Wnt11 transcription by regulating Smad3 binding to the Wnt11 promoter and by modulating Wnt11 promoter activity. Together, these findings identify non-canonical Wnt11 as a regulator of myofibroblast differentiation and lung fibrosis. Full article

Understanding how genetic risk variants contribute to respiratory diseases requires mapping genome-wide association study (GWAS) signals to disease-relevant cell types and states within the human lung. Here, we integrated GWAS summary statistics for ten major respiratory diseases, including asthma, COPD, idiopathic pulmonary fibrosis (IPF), COVID-19, and lung cancer, using a large-scale single-cell transcriptomic dataset of more than 523,000 cells from the Human Lung Cell Atlas. Applying the single-cell Disease Relevance Score (scDRS) framework, we systematically identified shared and disease-specific cellular associations across four major compartments, namely epithelial, immune, endothelial, and stromal. We found that alveolar type II (AT2) cells represent a central susceptibility hub for asthma, COPD, and COVID-19, whereas disease-specific risk enrichment was observed in subpopulations such as CCL3⁺ alveolar macrophages in COVID-19 and adventitial fibroblasts in asthma. Importantly, subclustering revealed substantial heterogeneity within cell types, with distinct transcriptional programs underlying differential disease associations. For example, AT2 subclusters exhibited divergent susceptibility patterns to asthma versus COVID-19, reflecting immune-interacting versus antiviral states. Our results provide a systematic single-cell framework for linking genetic risk to the cellular architecture of the human lung and uncover both shared and disease-specific mechanisms underlying respiratory disease susceptibility. Full article

Alcohol use disorder (AUD) predisposes individuals to pneumonia, acute respiratory distress syndrome, and chronic obstructive pulmonary disease, yet the mechanisms underlying alcohol-related lung disease (ARLD) remain unclear. Alveolar type II (AT2) epithelial cells play a central role in ethanol (EtOH) metabolism, surfactant production, alveolar repair, and pulmonary innate immunity. To examine EtOH-mediated effects, immortalized human AT2 cells were treated with 22–130 mM EtOH for 6 h (concentration-dependent) and 65 mM EtOH for 6–72 h (time-dependent). Cytotoxicity, inflammation, surfactant lipid/protein dysregulation, fatty acid ethyl ester (FAEE) formation, cellular stress responses, AMP-activated protein kinase (AMPKα) signaling, and mitochondrial function were analyzed. EtOH disrupted surfactant homeostasis by reducing dipalmitoylphosphatidylcholine and surfactant protein C (SP-C). Importantly, EtOH inactivated AMPKα, downregulated CPT1A (involved in β-oxidation of fatty acids), and upregulated lipogenic proteins ACC1 and FAS, accompanied by increased ER stress markers (GRP78, p-eIF2α, and CHOP). Expression of carboxyl ester lipase (FAEE-synthesizing enzyme) and FAEE levels increased with EtOH exposure, further exacerbating oxidative and ER stress, impairing mitochondrial energetics, ATP production, and AT2 cell function. These findings suggest that EtOH-induced FAEE formation, dysregulation of AMPKα-CPT1A signaling, and surfactant contribute to AT2 cell dysfunction and play a critical role in the pathogenesis of ARLD. Full article

Background/Objectives: β-Carotene oxygenase-2 (BCO2) is a mitochondrial carotenoid-cleaving enzyme expressed in multiple tissues, including the lungs. While BCO2 regulates carotenoid handling, its role in shaping pulmonary immune architecture and antiviral responses is unknown. We hypothesized that BCO2 deficiency reprograms epithelial–innate circuits and alters antiviral outcomes. Methods: BCO2-knockout (KO) and C57BL/6J wild-type (WT) mice underwent lung single-cell RNA sequencing (scRNA-seq), immunoblotting, and intranasal SARS-CoV-2 challenge to assess cell-type heterogeneity, pathway programs (by gene set variation analysis, GSVA), and antiviral responses. Results: scRNA-seq resolved 14 major lung cell populations with cell-type-specific pathway shifts. Compared with WT, BCO2 KO lungs showed increased conventional dendritic cells and natural killer (NK) cells, with reductions in macrophages, B cells, and endothelial cells. In KO alveolar type II cells, GSVA indicated a stress-adapted metabolic program. Ciliated epithelium exhibited vitamin-K-responsive and axoneme-remodeling signatures with attenuated glucocorticoid and very-low-density lipoprotein remodeling. Innate lymphoid type 2 cells favored fatty acid oxidation and chromatin dynamics with reduced mitochondrial activity. NK cells were biased toward constitutive chemokine/cytokine secretion and counter-inflammatory signaling. Immunoblotting confirmed the elevated level of interferon regulatory factor-3 protein in BCO2-KO lungs. Functionally, BCO2-KO mice had improved outcomes after intranasal SARS-CoV-2 exposure. Conclusions: Loss of BCO2 reconfigures the pulmonary immune landscape and enhances antiviral responsiveness in mice. These findings identify BCO2 as a nutrient-linked enzyme with immunomodulatory impact and highlight cell-state changes as candidate mechanisms for improved antiviral tolerance. Full article

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) primarily causes mild to moderate respiratory illness in humans, but infection can also lead to long-term complications, including chronic fatigue, respiratory and cardiac issues, or even death. In November 2021, the emergence of the highly transmissible Omicron variant marked a significant shift in the pandemic, with its subvariants rapidly spreading and continuing to evolve worldwide. The continuing introduction of Omicron subvariants underscores the need for the development of up-to-date vaccines, as well as for appropriate animal models in which they can be evaluated. Among these subvariants, XBB.1.5 stands out for its ability to evade the immune response from previous infection or vaccination. The objective of this study was to determine the disease course in African green monkeys (AGMs) following intranasal exposure to the XBB.1.5 subvariant. In four intranasally exposed AGMs, histopathological findings in the lungs consistent with SARS-CoV-2 infection included lymphohistiocytic and neutrophilic bronchiolitis with variable numbers of syncytial cells, to terminal bronchiole-centric, bronchointerstitial pneumonia with alveolar type II (AT2) pneumocyte hyperplasia, with evidence of acute alveolar injury, including alveolar septal necrosis and hyaline membrane formation. The two males showed more severe pneumonia compared to the two females. SARS-CoV-2 RNA was detected in the lungs or tracheobronchial lymph nodes in the males but not in the females, which correlated with higher cumulative lung pathology scores in the males. In the females, SARS-CoV-2 RNA was limited to the colon and nasal turbinates. Our results indicate that AGMs exhibit a disease course similar to most humans when exposed intranasally, making them a suitable model for studying mild to moderate SARS-CoV-2 infection. Therefore, further work is warranted to determine if this model could have utility for the evaluation of vaccine and therapeutic candidates against contemporary SARS-CoV-2 variants. Full article

Background/Objectives: Spheroid cultures in Matrigel are routinely used to study cell behaviour in complex 3D settings, thereby generating preclinical models of disease. Ideally, researchers would like to modulate gene expression ‘in situ’ for testing novel gene therapies while conserving the spheroid architecture. Here, we aim to provide an efficient method to transfect small RNAs (such as microRNAs and small interfering RNAs, i.e., siRNAs) into human induced pluripotent stem cell (iPSC)-derived 3D lung spheroids, specifically alveolar type II epithelial cells (iAT2) and basal cell (iBC) spheroids. Methods: Transfection of iAT2 spheroids within 3D Matrigel ‘in situ’, whole spheroids released from Matrigel or spheroids dissociated to single cells was explored via flow cytometry using a fluorescently labelled siRNA. Validation of the transfection method was performed in iAT2 and iBC spheroids using siRNA and miRNA mimics and measurement of specific target expression post-transfection. Results: Maximal delivery of siRNA was achieved in serum-free conditions in whole spheroids released from the Matrigel, followed by whole spheroids ‘in situ’. ‘In situ’ transfection of SFTPC-siRNA led to a 50% reduction in the SFTPC mRNA levels in iAT2 spheroids. Transfection of miR-29c mimic and miR-21 pre-miR into iAT2 and iBC spheroids, respectively, led to significant miRNA overexpression, together with a significant decrease in protein levels of the miR-29 target FOXO3a. Conclusions: This study demonstrates successful transfection of iPSC-derived lung spheroids without disruption of their 3D structure using a simple and feasible approach. Further development of these methods will facilitate functional studies in iPSC-derived spheroids utilizing small RNAs. Full article