Search Results (253)

Exposure of healthy tissue to ionizing radiation (IR) occurs due to nuclear accidents and terrorism, as well as radiotherapy. The vascular endothelium is a key target of IR, and microvascular endothelial cells (ECs) are particularly vulnerable to radiation. IR induces EC activation leading to endothelial cell injury. Human ghrelin is a stomach-derived peptide with pleiotropic effects, including protection against inflammation. We hypothesize that human ghrelin improves survival in total body irradiation (TBI) and that ghrelin’s protective effect could be mediated by attenuating endothelial cell injury. To test this, mice were exposed to TBI and after 24 h were treated subcutaneously with human ghrelin once daily for 4 days and monitored for 30 days. The survival rate of the human ghrelin-treated group was significantly higher than that of the vehicle group. Subsequently, human ghrelin treatment showed an effective dose modification factor of 1.0681. On day 4 after TBI, human ghrelin significantly attenuated EC permeability in the lungs and improved tight junction protein ZO-1 expression. Human ghrelin also improved ZO-1 and Claudin5 expression in primary mouse lung vascular endothelial cells. Taken together, these results indicate that human ghrelin improves survival after TBI, and its survival benefit is in part due to the attenuation of EC permeability and microvascular barrier dysfunction. Full article

Complement and pathogenic antibodies act independently and together to mediate the pathology of many autoimmune diseases. To address these drivers of disease, we generated a monoclonal antibody (mAb), CSL305, that binds and inhibits both complement and the neonatal Fc (fragment crystallizable) receptor FcRn. The fragment antigen binding (Fab) portion of CSL305 was engineered to bind both human C2 (huC2) zymogen and the active fragment huC2b to inhibit the classical and lectin complement pathways in vitro, and C3b deposition on primary lung endothelial cells using a 3-dimensional microvascular model system. Engineering of a triple amino acid mutation (“YPY” motif) into the Fc region of CSL305 increased its affinity to FcRn at both acidic and neutral pH, allowing it to also act as a potent FcRn antagonist. Intracellular trafficking experiments demonstrated that CSL305, but not the wild-type (WT) mAb lacking the YPY motif, was able to block immunoglobulin G (IgG) recycling in vitro. The generation of a high resolution 2.6Å crystal structure of CSL305 Fab region bound to huC2b showed that the epitope lies directly over the huC2b catalytic triad, providing evidence of its complement mechanism of action as a neutralising mAb. Early pharmacokinetic (PK)/pharmacodynamic (PD) studies using CSL305 in cynomolgus monkeys demonstrated both complement inhibition and FcRn antagonism in vivo, with reductions in complement classical pathway activity and endogenous IgG observed following single intravenous (IV) administration. CSL305 thus represents a dual-functional mAb as a potential therapeutic candidate. Full article

Fibrosis is a hallmark of the tumor microenvironment in many solid cancers, driving tumor progression, immune evasion, and treatment resistance; however, the molecular and cellular mechanisms underlying fibrogenesis—particularly stromal–immune crosstalk across organs—remain incompletely understood, compounded by organ-specific heterogeneity and a lack of reliable immune-related biomarkers. To address this, we performed an integrative single-cell RNA sequencing (scRNA-seq) analysis of fibrotic tissues from four major organs—liver, lung, heart, and kidney—alongside non-fibrotic controls, applying unsupervised clustering, trajectory inference, cell–cell communication modeling, and gene set variation analysis (GSVA) to map the fibro-immune landscape. Our analysis revealed both conserved and organ-specific features: fibroblasts were the dominant extracellular matrix (ECM)-producing cells in liver and lung, whereas endothelial-derived stromal populations prevailed in heart and kidney. Immune profiling uncovered distinct infiltration patterns—macrophages displayed organ-specific polarization states; T cells were enriched for tissue-resident subsets in lung and mucosal-associated invariant T (MAIT) cells in liver; and B cells exhibited marked heterogeneity, including a pathogenic interferon-responsive subset prominent in pulmonary fibrosis. GSVA further identified divergent signaling programs across organs and lineages, including TGF-β/TNF-α in the heart, NOTCH/mTOR in the kidney, glycolysis/ROS in the lung, and KRAS/interferon pathways in the liver. Cell–cell communication analysis highlighted robust crosstalk between macrophages, T/B cells, and stromal cells mediated by collagen, laminin, and CXCL signaling axes. Together, this cross-organ atlas delineates a highly heterogeneous fibro-immune ecosystem in human fibrotic diseases, revealing shared mechanisms alongside organ-specific regulatory networks, with immediate translational implications for precision anti-fibrotic therapy, immunomodulatory drug repurposing, and the development of context-specific biomarkers for clinical stratification and therapeutic monitoring. Full article

Background: Non-small cell lung carcinoma (NSCLC) is the most prevalent form of lung cancer, and its progression is closely associated with constitutive activation of signal transducer and activator of transcription 3 (STAT3). This study used surface plasmon resonance (SPR) technology to develop a STAT3-targeting recognition system and identify natural STAT3-targeting compounds from the traditional Chinese medicine Psoralea corylifolia and to evaluate their anti-NSCLC activities, with particular attention to reactive oxygen species (ROS) regulation. Methods: The SPR biosensor immobilized with STAT3 was used to screen and enrich STAT3-binding constituents of Psoralea corylifolia, and to determine ligand-STAT3 affinities. Molecular docking was performed to characterize interactions within the STAT3 SH2 domain. Functional effects were assessed in A549 cells using proliferation and scratch migration assays. Antioxidant capacity was evaluated via hydroxyl radical and superoxide anion scavenging assays, and intracellular ROS levels were measured in hydrogen peroxide (H₂O₂)-induced oxidative stress models in human umbilical vein endothelial cells (HUVECs) and A549 cells. Results: SPR analysis showed that psoralen and isopsoralen bind to STAT3, with equilibrium dissociation constants (KD) of 80.92 µM and 28.11 µM, respectively. Molecular docking further confirmed their interaction with the STAT3 SH2 domain. Both compounds inhibited A549 proliferation and reduced migration. Beyond direct STAT3 inhibition, both compounds demonstrated notable free radical scavenging activity. In a H₂O₂-induced oxidative stress model, pretreatment with psoralen or isopsoralen significantly reduced ROS levels in HUVECs, while increasing ROS accumulation in A549 lung cancer cells. Conclusions: This work identifies psoralen and isopsoralen as novel dual-function STAT3 inhibitors that exert anti-NSCLC effects through combined STAT3 suppression and context-dependent ROS modulation, and demonstrates the utility of SPR for screening bioactive natural products. Full article

Endothelial cell (EC) barrier integrity is tightly regulated by the activity of the non-muscle myosin light chain kinase (nmMLCK) under diverse pathological inflammatory conditions (pneumonia, sepsis) and exposure to mechanical stress. Inflammatory stimuli, including lipopolysaccharide (LPS), cytokines, and damage-associated molecular patterns (DAMPs), increase EC permeability through nmMLCK-dependent EC paracellular gap formation. However, the exact mechanisms by which nmMLCK regulates vascular barrier dysfunction in acute lung injury (ALI) remain incompletely understood. We hypothesized that inflammation-induced ROS results in the peroxynitrite-mediated nitration of nmMLCK that contributes to EC barrier disruption. Human lung EC exposure to either the peroxynitrite donor, SIN-1, or to LPS, triggered significant nmMLCK nitration, which was abolished by the oxidant scavenger, MnTMPyP. Mass spectrometry of SIN-1-treated nmMLCK identified multiple nitrated tyrosines. Nitration of Y1410 proved a critical PTM as site-directed substitution with alanine (Y1410A) abolished both SIN-1- and LPS-induced nmMLCK nitration. nmMLCK nitration disrupts wild-type nmMLCK interaction with Kindlin-2, a cytoskeletal regulator of vascular barrier stability, whereas EC transfected with the Y1410A nmMLCK mutant exhibited preserved Kindlin-2 binding, reflected by alterations in trans-EC electrical resistance (TEER). Consistent with these observations, LPS-challenged murine lungs displayed enhanced nmMLCK nitration and diminished nmMLCK-Kindlin-2 association. Functionally, SIN-1 markedly impaired EC barrier integrity (TEER), which was not observed in ECs expressing the Y1410A mutant. Together, these findings suggest that nmMLCK nitration at Y1410 is a critical molecular mechanism contributing to vascular leakage, highlighting this modification as a potential therapeutic target to reduce inflammation-induced vascular permeability. Given nmMLCK’s established role in barrier regulation, we hypothesized that LPS-induced peroxynitrite formation may promote the nitration of nmMLCK tyrosine residues: a PTM that potentially contribute to nmMLCK’s regulation of EC barrier integrity. Full article

Pulmonary hypertension (PH) causes morbidity and mortality in sickle cell disease (SCD). The release of heme during hemolysis triggers endothelial dysfunction and contributes to PH. Long non-coding RNAs (lncRNAs) may play a pivotal role in endothelial dysfunction and PH pathogenesis. This study assessed the regulatory role of the lncRNA–heme oxygenase-1 (HMOX1) axis in SCD-associated PH pathogenesis. Total RNAs were isolated from the lungs of 15–17-week-old sickle cell (SS) mice and littermate controls (AA) mice and subjected to lncRNA expression profiling using the Arrystar™ lncRNA array. Volcano plot filtering was used to screen for differentially expressed lncRNAs and mRNAs with statistical significance (fold change > 1.8, p < 0.05). A total of 3915 lncRNAs were upregulated and a total of 3545 lncRNAs were downregulated in the lungs of SS mice compared to AA mice. To validate differentially expressed lncRNAs, six upregulated lncRNAs and six downregulated lncRNAs were selected for quantitative PCR. MALAT1 expression was significantly upregulated in the lungs of SS mice and in hemin-treated human pulmonary artery endothelial cells (HPAECs), suggesting that hemolysis induces MALAT1. Functional studies revealed that MALAT1 depletion increased, while MALAT1 overexpression decreased, the endothelial dysfunction markers endothelin-1 (ET-1) and vascular cell adhesion molecule-1 (VCAM1), indicating a protective role of MALAT1 in maintaining endothelial homeostasis. In vivo, adenoviral MALAT1 overexpression attenuated PH, right ventricular hypertrophy (RVH), vascular remodeling, and reduced ET-1 and VCAM1 expression in SS mice. Given that HMOX1 protects endothelial cells during hemolysis, we observed that HMOX1 expression and activity were elevated in SS mouse lungs and hemin-treated HPAECs. HMOX1 knockdown enhanced ET-1 and VCAM1 expression, confirming its endothelial-protective function. Importantly, MALAT1 overexpression increased HMOX1 expression and activity, whereas MALAT1 knockdown reduced HMOX1 levels and mRNA stability. Collectively, these findings identify MALAT1 as a protective regulator that mitigates endothelial dysfunction, vascular remodeling, and PH in SCD, at least in part through the induction of HMOX1. These results suggest that SCD modulates the MALAT1–HMOX1 axis, and further characterization of MALAT1 function may provide new insights into SCD-associated endothelial dysfunction and PH pathogenesis, as well as identify novel therapeutic targets. Full article

Analysis of pulmonary vascular dysfunction in various lung pathologies remains challenging due to the lack of functional ex vivo models. Paracrine signaling in the lung plays a critical role in regulating endothelial maturation and vascular homeostasis. Previously, we employed single-cell RNA-sequencing (scRNAseq) to systematically map ligand–receptor (L/R) interactions within the lung vascular niche. However, the functional impact of these ligands on endothelial biology remained unknown. Here, we systematically evaluated selected ligands in vitro to assess their effects on endothelial barrier integrity, anti-inflammatory responses, and phenotypic maturation. Among the top soluble ligands, we found that adrenomedulin (ADM) exhibited superior barrier enhancing effect on human pulmonary endothelial cell monolayers, as evidenced by electrical cell impedance sensing (ECIS) and XperT assays. ADM also exhibited anti-inflammatory properties, decreasing ICAM1 and increasing IkBa expression in a dose-dependent manner. Perfusion is commonly used in bioengineered vascular model systems. Shear stress (15 dynes/cm²) alone increased endothelial characteristics, including homeostatic markers such as CDH5, NOS3, TEK, and S1PR1. ADM treatment maintained the enhanced level of these markers under shear stress and further improved anti-coagulation by increasing THBD and decreasing F3 expression and synergistically enhanced the expression of the native lung aerocyte capillary endothelial marker EDNRB. This effect was completely attenuated by a blockade of ADM receptor, RAMP2. Together, these findings identify ADM/RAMP2 signaling as a key paracrine pathway that enhances vascular barrier integrity, anti-inflammatory phenotype, and endothelial homeostasis, providing a framework for improving the physiological relevance of engineered vascular models. Full article

Microgravity (µg)-generated three-dimensional (3D) multicellular aggregates can serve as models of tissue and disease development. They are relevant in the fields of cancer and in vitro metastasis or regenerative medicine (tissue engineering). Driven by the 3R concept—replacement, reduction, and refinement of animal testing—µg-exposure of human cells represents a new alternative method that avoids animal experiments entirely. New Approach Methodologies (NAMs) are used in biomedical research, pharmacology, toxicology, cancer research, radiotherapy, and translational regenerative medicine. Various types of human cells grow as 3D spheroids or organoids when exposed to µg-conditions provided by µg simulating instruments on Earth. Examples for such µg-simulators are the Rotating Wall Vessel, the Random Positioning Machine, and the 2D or 3D clinostat. This review summarizes the most recent literature focusing on µg-engineered tissues. We are discussing all reports examining different tumor cell types from breast, lung, thyroid, prostate, and gastrointestinal cancers. Moreover, we are focusing on µg-generated spheroids and organoids derived from healthy cells like chondrocytes, stem cells, bone cells, endothelial cells, and cardiovascular cells. The obtained data from NAMs and µg-experiments clearly imply that they can support translational medicine on Earth. Full article

Background: Pneumonia contributes to post-burn morbidity and mortality. Understanding the mechanisms that predispose burn patients to pneumonia is crucial to both stratifying patients at increased risk and developing targeted interventions. Methods: A prospective observational study was conducted with 47 human patients who sustained large burn injuries with serum collected on days 2 and 3 post-burn and assessed for Angiopoietin-1 (Ang-1) and -2 (Ang-2). C57BL/6 mice were subjected to either sham injury or a 12.5% total body surface area (TBSA) scald burn injury, and plasma and lungs were assessed. Results: Patients who developed pneumonia within 30 days of injury had higher serum Ang-2 and Ang-2/1 ratio on post-injury days 2 and 3. Similar to patient findings, we observed an increase in Ang-2 in burn mice compared to sham. Within the lungs of burn mice, we found significant increases in Tyrosine kinase with immunoglobulin and epidermal growth factor homology domains 2 (TIE2) receptor transcript Tek, downstream mediators TNFAIP3 Interacting Protein 2 (Tnip2) and phosphoinositide-3-kinase regulatory subunit 1 (Pik3r1), in addition to endothelial adhesion molecules intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), along with neutrophil infiltration and markers compared to sham. Conclusions: These findings suggest that burn injury increases Angiopoetin-2 and downstream signaling in the lungs, which may contribute to post-burn pulmonary dysfunction. Further studies are necessary to understand if modulating the Ang–TIE2 axis can protect against pneumonia post-burn. Full article

E-cigarettes (E-cigs) are increasing in popularity and are considered a potentially safer alternative to traditional cigarettes. However, prior studies have demonstrated that inhalation of nicotine-containing e-cigs can cause substantial pathophysiologic changes, and “vaping” of some substances has led to severe lung damage. Our group recently described the role of cortactin (CTTN), a cytoskeletal actin-binding regulatory protein, in mediating cigarette smoke (CS) and E-cig-induced lung endothelial apoptosis and mitochondrial dysfunction. In the current study, we advance this work by characterizing the effects of E-cig on lung endothelial nanomechanical properties and barrier function. Lung EC exposure to E-cig extract (50 µg/mL) resulted in disruption of endothelial barrier properties as assessed by Electric Cell–Substrate Impedance Sensing (ECIS). Since excess mitochondrial reactive oxygen species (mitoROS) is an important marker of mitochondrial dysfunction, we next assessed the effect of Mito-TEMPO (10 µM, 3 h), a cell-permeable antioxidant, on E-cig-induced endothelial permeability. Pretreatment with Mito-TEMPO provided EC barrier protection after E-cig challenge, suggesting a key role of mitoROS in E-cig-induced EC permeability. E-cig exposure induces cytoskeleton rearrangement, leading to gap formation in lung EC, and significantly alters EC elastic properties as assessed by atomic force microscopy (AFM). Reduction in CTTN expression by siRNA further augmented the injurious effects of E-cig on EC permeability and elastic properties. This is the first study to explore the role of CTTN in evaluating the effect of E-cigarette exposure on the lung endothelium using AFM and provides novel mitochondrial and biophysical characterization of the effects of E-cig exposure on human lung EC. This work advances our understanding of the pathophysiologic effects of E-cig exposure. Full article

Sepsis remains a major cause of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), conditions characterized by high mortality and limited therapeutic options. Among the diverse inflammatory pathways implicated in their pathogenesis, the CXCL12/CXCR4 chemokine axis has gained increasing attention for its dual capacity to drive acute inflammation while also supporting tissue repair. Although numerous studies have investigated this signaling pathway, an integrated framework that reconciles its context-dependent functions, upstream regulatory mechanisms, and translational relevance has been lacking. In this review, we synthesize current evidence on the multifaceted roles of the CXCL12/CXCR4 axis in sepsis-induced ALI, highlighting its cell-type-specific effects in neutrophils, macrophages, alveolar epithelial cells, and endothelial cells through downstream pathways such as NF-κB, MAPK, and PI3K/Akt. We further evaluate emerging therapeutic approaches, including small-molecule antagonists (e.g., AMD3100), natural products, and epigenetic modulators. Newly added sections summarize the upstream regulation of CXCL12 by hypoxia, cytokines, and epigenetic factors, discuss the regulatory influence of the alternative receptor CXCR7/ACKR3, and differentiate preclinical insights from human clinical observations. Finally, we outline key obstacles to clinical translation and propose future directions to develop precision medicine strategies that more effectively target this axis. Collectively, our analysis suggests that although the CXCL12/CXCR4 pathway represents a promising target for ALI/ARDS therapy, its context-dependent and cell-specific actions demand carefully tailored modulation rather than uniform inhibition. Full article

The paper is concerned with experimental investigations and numerical simulations of airflow in a rigid model of human tracheal bifurcation during a respiratory cycle in the presence of cough. The main goal of the study is to calculate the velocity and tracheal wall shear stress (WSS) distributions under the time variation in the pressure difference. A sequence of inspiration-expiration of measured flow rates and pressure is used to calibrate the 3D unsteady numerical solutions for different imposed boundary conditions at the edges of the bifurcation. The experimental data are obtained using commercial medical devices: (i) a spirometer and (ii) a mechanical ventilator, respectively. CT images of the lung airways were used to reconstruct the tracheal test geometry by 3D printing techniques. Flow spectrum, vortical structures, and the wall stresses are analyzed for the computed cases. Four turbulence models (k − ɛ, k − ω SST, k − ɛ R, and LES) are compared, and all indicate an increase in peak WSS and vortex intensity during coughing versus normal expiration. The present work confirms the importance of CFD simulations to model and quantify airflow throughout the respiratory cycle. The paper proposes a method to calculate wall shear stress, one of the most relevant parameters for characterizing airway function and the mechanical response of tracheal endothelial cells. 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

Clinical application of ex vivo lung perfusion (EVLP) has increased marginal donor lung utilization. It has been developed as a platform for donor lung reconditioning. However, many of the current repair strategies are limited by a maximum reliable EVLP circuit duration of 12 h. Past studies have successfully extended EVLP through nutrient supplementation, but the exact components and respective mechanisms by which EVLP is extended remains unknown. As such, the focus of this study was to systematically evaluate the effects of nutritional supplements in EVLP perfusates on cell apoptosis, viability, confluence, and migration. To test this, we developed a high-throughput human lung endothelial cell culture platform where experimental perfusates with various combinations of GlutaMAX (a glutamine dipeptide), Travasol (amino acids), Intralipid (lipids), Multi-12 (vitamins), cysteine, and glycine were tested using the Incucyte Live imaging system. GlutaMAX supplementation alone significantly reduced apoptosis, improved viability and cell migration beyond all other supplements and further outperformed standard endothelial cell culture medium. Travasol offered short-term benefits, while Intralipid offered minimal functional support. Multi-12 improved viability and apoptosis independently and in combination with other supplements. The best experimental perfusate targeted the glutathione synthesis pathway, combining GlutaMAX, cysteine and glycine and further reduced apoptosis compared with GlutaMAX alone. Collectively, these results suggest that nutrient selection during EVLP is critical and highlights the need to systematically evaluate perfusate modifications as opposed to broad-spectrum nutrient delivery. This in vitro model provides a cost-effective platform for preclinical screening of perfusate modifications to enhance organ viability during EVLP. Full article

The role of mesenchymal-to-endothelial transition in the angiogenic response remains controversial. In this study, we investigated whether human fetal lung fibroblasts (MRC-5 cells) exhibit morphological plasticity in a biomimetic extracellular matrix environment. To this end, MRC-5 cells were first cultured on and within Matrigel hydrogel and then studied with tube formation assays, confocal/fluorescence microscopy, invasion assays, and transcriptomic profiling. In addition, quantitative assessment for cord formation and gene expression was conducted via qPCR and RNA sequencing. In this study, MRC-5 cells quickly self-organized into cord-like networks, resembling early stages of vascular patterning, and at higher densities, invaded the hydrogel and formed spheroid-like aggregates. Transcriptomic analysis revealed upregulation of genes related to nervous system development and synaptic signaling in Matrigel-grown MRC-5 cultures. Collectively, these findings suggest that MRC-5 fibroblasts display structural and transcriptional plasticity in 3D Matrigel cultures, forming vascular-like cords that are more likely to resemble early developmental morphologies or neuroectodermal-like transcriptional signatures than definitive endothelial structures. This work underscores the potential of fibroblasts as an alternative cell source for vascular tissue engineering and highlights a strategy to overcome current limitations in autologous endothelial cell availability for regenerative applications. Full article