Purpose:Visual dysfunction due to optic neuritis (ON) is an early clinical manifestation of multiple sclerosis (MS). ON is characterized by inflammation of the optic nerve, demyelination, axonal damage, and retinal ganglion cell (RGC) loss. Previously, we showed that spermine oxidase (SMOX), a polyamine catabolizing enzyme, modulates visual function in an experimental model of ON. Using proteomic analysis, the present study aimed to identify SMOX-regulated molecular pathways involved in ON-associated visual dysfunction. Methods:Experimental autoimmune encephalomyelitis (EAE) was induced in wild-type (WT) and SMOX-deficient (Smox KO) mice. Clinical scoring of mice was recorded daily. Optic nerves from WT and Smox KO EAE mice and their controls were collected and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Pathway enrichment and comparative analyses were performed to identify key processes and pathways regulated by SMOX. Immunofluorescence was performed to detect changes in the expression of key proteins. Results:Smox KO EAE mice showed delayed and reduced clinical scores. Pathway enrichment analysis identified several key processes affected in EAE, including regulation of the actin cytoskeleton, tight junction integrity, and platelet activation/aggregation. The comparative analysis of the WT EAE and Smox KO EAE proteomes, together with false discovery rate (FDR)-corrected pathway enrichment analysis, indicated attenuation of neuroinflammatory pathways in the SMOX-deficient optic nerve. Furthermore, SMOX deficiency restored key cytoskeletal and cellular-adhesion proteins essential for neuronal integrity. Immunofluorescence studies confirmed dysregulation of receptor for activated C kinase 1 (RACK1), actinin alpha 4 (ACTN4), high mobility group box 1 (HMGB1), and S100 calcium-binding protein B (S100B), critical proteins involved in immune signaling, cytoskeletal stability, and inflammation. Conclusions:These findings indicate the impact of SMOX on inflammation and cytoskeletal stabilization in ON and its potential as a therapeutic target in preserving vision in MS.

Laboratory-guided methods have the potential to provide robust mortality prediction for acute respiratory distress syndrome (ARDS) which could improve timely intervention. The objective of this investigation was to predict mortality using regression and machine learning techniques using biomarkers linked to ARDS pathophysiology, including matrix metalloproteinase-3 (MMP-3) and club cell-secretory protein-16 (CC16), and general inflammatory biomarkers. 89 adult patients from the "Aerosolized β₂-agonist for treatment of acute lung injury" (ALTA) trial were randomly separated into training (n = 53), validation (n = 8), and test (n = 28) sets. Logistic regression and supervised machine learning (ML) models were developed. In total, 20 ICU predictors including baseline characteristics (age, sex, APACHE III score, sepsis, vasoactive agent, PaO2/FiO2) and baseline and serial biomarkers were included. The primary outcome was area under the receiver operating characteristic (AUROC) for 90 day mortality. Random Forest, Support Vector Machine (SVM), and XGBoost achieved AUROCs of 0.917, 0.705, and 0.955, respectively. Stepwise regression achieved an AUROC of 0.508. For the highest performing model (XGBoost), MMP3-based variables were the most important features. ML had high predictive ability for 90-day mortality, and MMP-3 demonstrates moderate-to-high feature importance in ML models. These findings support using pathophysiology-derived biomarkers in ML models for ARDS prediction.

ObjectivesTo evaluate the association between ICU-acquired infections and 28-day mortality in pneumonia-induced sepsis and to explore associated immune-related gene expression patterns.MethodsA secondary analysis was performed using the publicly available GSE65682 dataset, including adult ICU patients with sepsis secondary to community-acquired pneumonia (CAP) or hospital-acquired pneumonia (HAP). Patients were stratified based on the development of ICU-acquired infections. 28-day mortality and whole-blood leukocyte gene expression at ICU admission were compared between groups.ResultsAmong 144 patients, 20 developed ICU-acquired infections. In the CAP subgroup, ICU-acquired infections were associated with numerically higher 28-day mortality compared to those without infection (45.5% vs. 18.2%, p = 0.05), although this finding should be interpreted with caution given the retrospective study design and limited sample size. In HAP patients, a similar pattern was not observed (22.2% vs. 19.6%). Transcriptomic analysis showed significant downregulation of the interleukin-7 receptor (IL7R) in CAP patients who developed ICU-acquired infections, with PRKACB and CD3D also demonstrating a downward trend.ConclusionThese findings suggest that early immune dysregulation may be associated with an increased susceptibility to secondary infections and potentially worse outcomes among CAP patients. IL7R may represent a candidate signal of immune dysregulation and warrants further investigation and validation in future studies.

Background:Corticosteroids are commonly used in critically ill patients with established risk factors for acute respiratory distress syndrome (ARDS), often for indications like sepsis or pneumonia, yet the choice of steroid and its impact on outcomes remain debated. Methods:We conducted a retrospective analysis of 160 ICU patients with documented clinical risk factors for ARDS at the time of ICU admission to evaluate the effect of corticosteroid therapy on hospital mortality. Clinical characteristics, treatment variables, and outcomes were compared between patients who received corticosteroids and those who did not. A subgroup exploratory analysis further compared outcomes between dexamethasone and hydrocortisone users. Logistic regression models were used to identify mortality predictors. Results:Of 160 patients, 91 (56.9%) received corticosteroids. Steroid-treated patients had higher Simplified Acute Physiology Score II (SAPS II) scores (54.4 vs. 48.0, p = 0.011), but no significant differences in age, partial pressure of arterial oxygen to fraction of inspired oxygen ratio (PaO2/FiO2), or mechanical ventilation use. Overall mortality was not significantly different between steroid and non-steroid users (42.9% vs. 33.3%, p = 0.221). Among steroid-treated patients, dexamethasone (n = 26) and hydrocortisone (n = 50) were the most frequently used agents. Mortality was significantly higher with hydrocortisone (58%) compared to dexamethasone (26.9%) (p = 0.010). In multivariate analysis, hydrocortisone use was associated with higher hospital mortality (adjusted OR = 4.41; 95% CI: 1.11-17.48; p = 0.035). Conclusion:Overall corticosteroid use was not associated with improved survival in patients with documented clinical risk factors for ARDS; however, in an exploratory analysis, hydrocortisone use was associated with higher hospital mortality than dexamethasone. Given the retrospective observational design and real-world factors influencing corticosteroid selection, including illness severity, these findings should be interpreted with caution and support the need for prospective studies to clarify these associations.

Cellular senescence is one of the major risk factors for the onset and progression of chronic pulmonary diseases. Cellular senescence can be induced by diverse stressors, including genotoxic damage, oncogenic signaling, and therapeutic interventions. These senescent cells communicate via the release of multiple inflammatory molecules known as the Senescence-Associated Secretory Phenotype (SASP), which induces persistent low-grade inflammation and contributes to various chronic inflammatory lung diseases. This review summarizes the basic concepts of cell senescence, its hallmarks, SASP, and the mechanisms of cell senescence in the lung, and its consequences in the development and progression of chronic pulmonary diseases. Current therapeutic strategies include senolytics (e.g., BCL-2 family inhibitors and dasatinib–quercetin) and senomorphics that suppress SASP activity. Future directions in the development of cell- and stage-specific therapies are critical for targeting age-related lung disease with desired outcomes.

Ribosomal UFMylation contributes to ribosome heterogeneity and is associated with ribosome-associated quality control at the endoplasmic reticulum. However, the specific pathophysiological functions of ribosomal UFMylation remain unknown. In this study, we systematically demonstrate the significance of UFMylation in the differentiation and maturation of hepatocytes using human embryonic stem cell-derived hepatocyte-like cells and liver bud organoids as experimental platforms. We also develop a strategy to identify UFMylated substrates and confirm that RPL26 is a substrate in the liver. Additionally, we discover that mice with the Rpl26 c.395A>G (p.K132R) mutation are more susceptible to steatosis induced by a high-fat diet. Further investigations reveal a key role of CDK5RAP3 and RPL26 UFMylation in regulating ribosome dissociation. Our findings suggest that ribosome UFMylation serves as an important safeguard for liver development and homeostasis and may represent a potential therapeutic target for nonalcoholic fatty liver disease.

Alterations in lipid profiles have been shown in patients with chronic obstructive pulmonary disease (COPD), but the underlying molecular mechanisms remain unclear. In this study, we aimed to investigate the role of cytochrome P450 family-1 subfamily B member 1 (CYP1B1) in cigarette smoke (CS)-induced lipid accumulation in alveolar type II epithelial (AT2) cells. We observed a steady increase in CYP1B1 protein levels in AT2 cells from COPD patients. Additionally, CS exposure induced CYP1B1 expression in AT2 cells of murine lungs. In vitro, treatment with cigarette smoke extract (CSE) not only upregulated CYP1B1 expression but also triggered lipid accumulation in AT2-like cells. Functionally, overexpression of CYP1B1 promoted lipid accumulation in A549 and MLE-12 cells. Consistently, siRNA-mediated CYP1B1 inhibition significantly reduced CSE-induced lipid accumulation in AT2-like cells. Furthermore, treatment with 2,3',4,5'-tetramethoxystilbene (TMS), a selective CYP1B1 inhibitor, reduced CSE-induced lipid accumulation. TMS also attenuated CSE-induced mitochondrial reactive oxygen species production and cell apoptosis. Taken together, our findings suggest that CYP1B1 is upregulated by CS exposure and plays a key role in CS-induced lipid accumulation in AT2 cells. Targeting CYP1B1 may offer a potential therapeutic strategy for addressing lipid dysregulation and lung pathology in patients with COPD.

Diabetes mellitus is a systemic disease characterized by chronic hyperglycemia, persistent inflammation, and oxidative stress. While the vascular complications of diabetes are well-documented, their impact on lung barrier integrity remains underexplored. In this study, we investigated the molecular mechanisms by which advanced glycation end-products (AGE) compromise the integrity of lung endothelial and epithelial barriers. Using human lung microvascular endothelial cells and epithelial (A549) cells, we assessed the impact of AGE on the tight junction protein claudin-5, adherens junction protein VE-cadherin, and key signaling molecules including the receptor for AGE (RAGE), phosphorylated Akt, and p38 MAPK as well as a panel of pro-inflammatory cytokines. Our findings demonstrated that AGE exposure (50 μg/mL) significantly activated Akt and p38 MAPK, upregulated Claudin-5 and RAGE, and downregulated VE-cadherin, correlating with reduced transendothelial electrical resistance in vitro. Notably, we observed similar effects on lung epithelial cells. Moreover, AGE-treated conditioned media from THP-1 macrophages induced a pronounced increase in inflammatory cytokines, amplifying the disruption of lung barrier integrity. These findings reveal a potential mechanism linking diabetes-induced vascular dysfunction and immune activation to compromised lung barrier function, emphasizing the need for further research into diabetes-associated lung complications.

Introduction: Acute lung injury results in endothelial dysfunction in systemic blood vessels, cardiac output, and an elevated risk of cardiovascular events. To date, no specific pharmacological interventions have been demonstrated to improve outcomes in acute lung injury. Long non-coding RNAs significantly influence the expression of various genes, impacting numerous physiological and pathological conditions. Previously, our team found that a lncRNA, named “long non-coding RNA, embryonic stem cells expressed 1” (Lncenc1), is strikingly upregulated in murine lungs following bacterial infection. CD59 is known to be highly expressed on vascular endothelial cells, where it blocks the complement system activation and membrane attack complex (MAC) deposition on the cell surface. However, the mechanism of Lncenc1 to CD59 on endothelial dysfunction and vascular permeability is currently unknown. Hypothesis: Lncenc1 modulates MAC deposition through CD59 during bacteria-induced endothelial dysfunction. Methods: Lncenc1 knockout ( Lncenc1 -/- ) mouse model was generated for this study. Hematoxylin-eosin (H&E) staining and lung wet-to-dry ratio measurement were confirmed to evaluate the severity of pulmonary edema. Pulmonary vascular permeability was induced by Klebsiella pneumoniae or Lipopolysaccharide and measured with Evans blue and fluorescein dye by tail-vein injection. Primary murine endothelial cells were isolated from mice for experimental use. Immunofluorescence staining and Western Blot were used to determine the MAC C5b-9 expression under infected conditions. Results: Our result indicates that Lncenc1 - /- mice exhibit improved outcomes in terms of survival, pulmonary edema, and vascular leakage. Furthermore, microarray analysis revealed that CD59 is the most significantly upregulated in the lungs of Lncenc1 - /- mice compared to wild-type controls. We also found that Lncenc1 deficiency attenuates bacteria-induced MAC deposition in primary murine endothelial cells. Consistently, treatment with extracellular vesicle-carried CD59 was found to reduce bacteria-induced endothelial barrier leakage. Conclusion: Our results demonstrate that Lncenc1 participates in the pathogenesis of bacteria-induced pulmonary edema and vascular leakage. Lncenc1 deficiency protects mice from bacteria-induced lung injury and endothelial barrier. Thus, Lncenc1 and its downstream modulator CD59 could be potential targets for the treatment of ALI-induced vascular dysfunction.

Cellular nucleosomes—the structural and functional units of chromatin—are inherently present in cells. During cellular damage or cell death, nucleosomes are released into circulation, either actively or passively. Once released, nucleosomes can become immunogenic entities through various mechanisms. The nucleosomal proteins in nucleosomes, called histones, play a pivotal role in inducing immunogenicity. However, intact nucleosomes are more immunogenic than the histones alone, as nucleosomal double-stranded deoxyribonucleic acid (dsDNA) enhances its immunogenic potential. Our recent study has shown that circulating histones are predominantly nucleosomal histones rather than free histones. Consequently, circulating histones primarily function as integral parts of circulating nucleosomes rather than acting independently. Circulating nucleosomes and their associated histones are implicated in the pathogenesis of a wide array of diseases. Notably, they are critical in the pathogenesis of lung injury and sepsis. These diseases have high morbidity and mortality rates and lack early diagnostic biomarkers. Further investigation is required to fully elucidate the role of circulating nucleosomes and their associated histones in disease processes. This review aims to discuss the current understanding of circulating nucleosomes and histones in the pathogenesis of lung injury and sepsis, with a focus on the underlying mechanisms.

Diabetes mellitus (DM) is a systemic disease known for its cardiovascular complications, but its impact on pulmonary health remains underexplored. We aimed to determine how pre-existing DM influences lung inflammation and susceptibility to acute lung injury (ALI). RNA sequencing was performed on lung tissues from streptozotocin-induced DM and non-DM mouse lungs, followed by gene enrichment and bioinformatics analysis. Lung inflammation and injury were assessed in a lipopolysaccharide-induced sepsis model using Wet/Dry lung weight ratios, histopathology, RT-qPCR, and cytokine profiling. Transcriptomic analysis revealed that DM lungs exhibited upregulated inflammatory pathways and signs of compromised endothelial barrier integrity. While LPS exposure induced lung inflammation, no additive or synergistic effect of DM and LPS was observed in exacerbating lung injury. However, DM alone was associated with increased expression of inflammatory cytokines (TNF-α, IL-1β, MCP-1, and CXCL-1), greater fluid accumulation, and structural lung changes indicative of enhanced baseline susceptibility to ALI. These findings underscore the impact of DM on priming the lung for inflammation and injury and suggest that targeting DM-associated molecular pathways may help mitigate pulmonary complications in diabetic individuals.

Mitogen-activated protein kinase (MAPK) p38 plays a key role in driving the pathology of acute lung injury (ALI), but effective therapeutic targeting remains elusive. Atypical p38 signaling, mediated by interaction with the adaptor protein Tumor Growth Factor β Activated Kinase 1 (TAK1) Binding Protein 1 (TAB1), has so far only been observed during pathological responses, representing a selective and alternative target during pulmonary injury. However, atypical signaling has not been investigated in the context of pulmonary injury and immune responses related to the onset and progression of ALI. Here, we utilized a genetic knock-in mouse to block influenza A-induced lung injury mediated by atypical signaling. We report that the loss of TAB1-p38 interaction reduces weight loss and recovery time, reduces histopathological scores associated with influenza-induced lung injury early during infection, and prompts earlier recruitment of monocytes to the lungs following infection. These results were found to be independent of viral replication and infectivity, representing the first evidence for the roles of atypical signaling as a driver of host-mediated pulmonary injury following influenza infection.

Emerging evidence suggests that autophagy is activated during exercise, mediating the benefits of exercise. However, the molecular mechanisms underlying the regulation of skeletal muscle autophagy during exercise are incompletely understood. Here, we show lactate severs as a positive regulator of autophagy in myocytes and its levels increase rapidly in response to a single bout of exercise. Mice with low lactate levels due to the lack of myocyte lactate dehydrogenase A exhibit significant abnormalities in skeletal muscle, including impaired autophagy. Our mechanistic study demonstrates that lactate enhances autophagy by inactivating mTOR complex 1 (mTORC1) through promoting mTOR lactylation at lysine 921 (K921) in myocytes. Accordingly, mutation of mTOR at K921 site causes sustained mTORC1 activation, leading to defects in skeletal muscle autophagy. Thus, our work uncovers a previously undescribed physiological action of lactate in the regulation of mTORC1-controlled skeletal muscle autophagy during acute exercise, which involves a lactylation-based post-translational modification mechanism.

Background:The cornerstone medications for maintenance of chronic obstructive pulmonary disease (COPD) have remained the same for decades. Despite combination therapy with multiple mechanisms of action, patients with COPD have significant morbidity and frequent exacerbations. New treatments with novel mechanisms of action are needed to decrease exacerbation and improve symptoms. Ensifentrine is a novel dual PDE 3 and 4 inhibitor emerged and established as a promising drug in the treatment and management of COPD. Objectives:The purpose of this study was to examine the pooled efficacy and safety of ensifentrine versus placebo for treatment of moderate to severe COPD. Data sources:We explored PubMed, MEDLINE, and Cochrane Library databases. Study eligibility criteria:Randomized controlled clinical trials (RCTs)comparing ensifentrine 3 mg twice daily to placebo for treating moderate-to-severe COPD were included. Design and method:A systematic review of three RCTs investigating the use of ensifentrine in adults with moderate to severe COPD was performed. Mean and risk differences with 95% confidence intervals (CI) were used to express the pooled effect on continuous and binary outcomes, respectively. Results:This systematic review included data from three randomized controlled trials encompassing a total of 1,715 patients. Of these, 1,057 patients received ensifentrine and 658 received placebo. Ensifentrine was associated with significant improvements in all primary outcomes compared to placebo. The pooled mean differences in peak FEV₁, average FEV₁, and morning trough FEV₁ were 143.91 mL, 91.71 mL, and 43.69 mL, respectively (all p < 0.05). Regarding secondary outcomes, ensifentrine significantly improved respiratory symptom scores assessed by the Evaluating Respiratory Symptoms in COPD (E-RS: COPD) tool (p = 0.02), as well as the Transition Dyspnea Index (TDI) score (p < 0.001). The incidence of adverse events was comparable between the ensifentrine and placebo groups. Conclusion:Ensifentrine consistently improved pulmonary function tests and symptom scores with a safe adverse effect profile. This systematic review supports the clinical benefits of ensifentrine in patients with moderate to severe COPD.

Tissue inhibitor of metalloproteinases-1 (TIMP-1) is a physiologic inhibitor of the matrix metalloproteinases (MMPs), but little is known about the role of TIMP-1 in regulating the pathogenesis of influenza A virus (IAV) infection. Here, we performed both in vivo and in vitro experiments to investigate the regulation and function of TIMP-1 during IAV infection. Specifically, plasma levels of TIMP-1 are significantly increased in human subjects and wild-type (WT) mice infected with 2009 H1N1 IAV compared with levels in uninfected controls. Also, TIMP-1 is strikingly upregulated in PDGFRα positive (PDGFRα+) cells in IAV-infected murine lungs as demonstrated using conditional KO (cKO) mice with a specific deletion of Timp-1 in PDGFRα+ cells. Our in vitro data indicated that TIMP-1 is induced by transforming growth factor-β (TGF-β) during lipofibroblasts (lipoFBs)-to-myofibroblast (myoFB) transdifferentiation. Timp-1 deficiency protects mice from H1N1 IAV-induced weight loss, mortality, and lung injury. IAV-infected Timp-1-deficient mice showed increased macrophages, and B and T cell counts in bronchoalveolar lavage (BAL) on day 7 postinfection (p.i.), but reduced BAL neutrophil counts. Increased Cxcl12 levels were detected in both BAL cells and lungs from Timp-1-deficient mice on day 3 p.i. Taken together, our data strongly link TIMP-1 to IAV pathogenesis. We identified that PDGFRα-lineage cells are the main cellular source of elevated TIMP-1 during IAV infection. Loss of Timp-1 attenuates IAV-induced mortality and promotes T and B cell recruitment. Thus, TIMP-1 may be a novel therapeutic target for IAV infection.NEW & NOTEWORTHY Our data strongly link tissue inhibitor of metalloproteinases-1 (TIMP-1) to influenza A virus (IAV) pathogenesis. TIMP-1 is highly increased in PDGFRα-lineage cells during IAV infection. Transforming growth factor-β (TGF-β) induces TIMP-1 during lipofibroblast (lipoFB)-to- myofibroblast (myoFB) transdifferentiation. Timp-1 deficiency protects mice from H1N1 IAV-induced weight loss, mortality, and lung injury. TIMP-1 may be a novel therapeutic target for IAV infection.

Diabetic retinopathy (DR) is a leading cause of blindness, yet its molecular mechanisms are unclear. Extracellular vesicles (EVs) contribute to dysfunction in DR, but the characteristics and functions of vitreous EVs are unclear. This study investigated the inflammatory properties of type 2 diabetic (db) vitreous EVs. EVs isolated from the vitreous of db and non-db donors were used for nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), immunogold staining, Western blotting, and proteomic analysis by mass spectrometry. Intracellular uptake of vitreous EVs by differentiated macrophages was evaluated using ExoGlow membrane labeling, and the impact of EVs on macrophage (THP-1) activation was assessed by cytokine levels using RT-qPCR. NTA and TEM analysis of db and non-db vitreous EVs showed non-aggregated EVs with a heterogeneous size range below 200 nm. Western blot detected EV markers (Alix, Annexin V, HSP70, and Flotillin 1) and an upregulation of Cldn5 in db EVs. While the db EVs were incorporated into macrophages, treatment of THP-1 cells with db EVs significantly increased mRNA levels of TNFα and IL-1β compared to non-db EVs. Proteomic and gene enrichment analysis indicated pro-inflammatory characteristics of db EVs. Our results suggest a potential involvement of EC-derived Cldn5+ EVs in triggering inflammation, offering a novel mechanism involved and presenting a possible therapeutic avenue for DR.

AbstractIncreased circulating tissue inhibitor of metalloproteinases‐1 (TIMP‐1) levels have been observed in patients with acute lung injury (ALI). However, the sex‐specific regulation of TIMP‐1 and the underlying molecular mechanisms have not been well elucidated. In this study, we found that plasma TIMP‐1 levels were significantly higher in COVID‐19 and H1N1 patients compared with those in healthy subjects (n = 25). TIMP‐1 concentrations were significantly different between males and females in each disease group. Among female but not male patients, TIMP‐1 levels significantly correlated with the PaO2/FiO2 ratio and hospital length of stay. Using the mouse model of ALI induced by the H1N1 virus, we found that TIMP‐1 is strikingly induced in PDGFRα‐positive cells in the murine lungs. Moreover, female mice showed a higher Timp‐1 expression in the lungs on day 3 postinfection. Mechanistically, we observed that estrogen can upregulate TIMP‐1 expression in lung fibroblasts, not epithelial cells. In addition, overexpression of estrogen receptor α (ERα) increased the TIMP‐1 promoter activity. In summary, TIMP‐1 is an estrogen‐responsive gene, and its promoter activity is regulated by ERα. Circulating TIMP‐1 may serve as a sex‐specific marker, reflecting the severity and worst outcomes in female patients with SARS‐CoV2‐ and IAV‐related ALI.

Pulmonary surfactants play a crucial role in managing lung lipid metabolism, and dysregulation of this process is evident in various lung diseases. Alternations in lipid metabolism lead to pulmonary surfactant damage, resulting in hyperlipidemia in response to lung injury. Lung macrophages are responsible for recycling damaged lipid droplets to maintain lipid homeostasis. The inflammatory response triggered by external stimuli such as cigarette smoke, bleomycin, and bacteria can interfere with this process, resulting in the formation of lipid-laden macrophages (LLMs), also known as foamy macrophages. Recent studies have highlighted the potential significance of LLM formation in a range of pulmonary diseases. Furthermore, growing evidence suggests that LLMs are present in patients suffering from various pulmonary conditions. In this review, we summarize the essential metabolic and signaling pathways driving the LLM formation in chronic obstructive pulmonary disease, pulmonary fibrosis, tuberculosis, and acute lung injury.