FoxO3 an important player in fibrogenesis and therapeutic target for idiopathic pulmonary fibrosis

Pharmacological Inhibition of Epac1 Protects against Pulmonary Fibrosis by Blocking FoxO3a Neddylation

Background

Idiopathic Pulmonary fibrosis (IPF) is characterized by progressive scarring and fibrosis within the lungs. There is currently no cure for IPF; therefore, there is an urgent need to identify novel therapeutic targets that can prevent the progression of IPF. Compelling evidence indicates that the second messenger, cyclic adenosine monophosphate (cAMP), inhibits lung fibroblast proliferation and differentiation through the classical PKA pathway. However, the contribution of the e xchange p rotein directly a ctivated by c AMP 1 (Epac1) to IPF pathophysiological processes is yet to be investigated.

Objective

To determine the role of the cAMP-binding protein Epac1 in the progression of IPF.

Methods

We used lung samples from IPF patients or healthy controls, mouse lung samples, or lung fibroblast isolated from a preclinical mouse model of PF induced by bleomycin intratracheal injection. The effect of bleomycin (BLM) treatment was determined in Epac1 knock-out mice or wild-type littermates. Epac1 expression was modulated in vitro by using lentiviral vectors or adenoviruses. The therapeutic potential of the Epac1-selective pharmacological inhibitor, AM-001, was tested in vivo and in vitro, using a bleomycin mouse model of PF and an ex vivo precision-cut lung slices (PCLs) model of human lung fibrosis.

Results

Epac1 expression was increased in the lung tissue of IPF patients, in IPF-diseased fibroblasts and in BLM-challenged mice. Furthermore, Epac1 genetic or pharmacological inhibition with AM-001 decreased normal and IPF fibroblast proliferation and the expression of profibrotic markers, αSMA, TGF-β/SMAD2/3, and interleukin-6 (IL-6)/STAT3 signaling pathways. Consistently, blocking Epac1 protected against BLM-induced lung injury and fibrosis, suggesting a therapeutic effect of Epac1 inhibition on PF pathogenesis and progression. Global gene expression profiling revealed a decrease in the key components of the profibrotic gene signature and neddylation pathway in Epac1-deficient lung fibroblasts and IPF human-derived PLCs. Mechanistically, the protective effect of Epac1 inhibition against PF development involves the inhibition of FoxO3a neddylation and its subsequent degradation by NEDD8, and in part, by limiting the proliferative capacity of lung-infiltrating monocytes.

Conclusions

We demonstrated that Epac1 is an important regulator of the pathological state of fibroblasts in PF and that small molecules targeting Epac1 can serve as novel therapeutic drugs against PF.

Mimosa pudica L. extract ameliorates pulmonary fibrosis via modulation of MAPK signaling pathways and FOXO3 stabilization

ETHNOPHARMACOLOGICAL RELEVANCE

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrosing pulmonary disorder that has a poor prognosis and high mortality. Although there has been extensive effort to introduce several new anti-fibrotic agents in the past decade, IPF remains an incurable disease. Mimosa pudica L., an indigenous Vietnamese plant, has been empirically used to treat respiratory disorders. Nevertheless, the therapeutic effects of M. pudica (MP) on lung fibrosis and the mechanisms underlying those effects remain unclear.

AIM OF THE STUDY

This study investigated the protective effect of a crude ethanol extract of the above-ground parts of MP against pulmonary fibrogenesis.

MATERIALS AND METHODS

Inflammatory responses triggered by TNFα in structural lung cells were examined in normal human lung fibroblasts and A549 alveolar epithelial cells using Western blot analysis, reverse transcription-quantitative polymerase chain reaction assays, and immunocytochemistry. The epithelial-to-mesenchymal transition (EMT) was examined via cell morphology observations, F-actin fluorescent staining, gene and protein expression measurements, and a wound-healing assay. Anti-fibrotic assays including collagen release, differentiation, and measurements of fibrosis-related gene and protein expression levels were performed on TGFβ-stimulated human lung fibroblasts and lung fibroblasts derived from mice with fibrotic lungs. Finally, in vitro anti-fibrotic activities were validated using a mouse model of bleomycin-induced pulmonary fibrosis.

RESULTS

MP alleviated the inflammatory responses of A549 alveolar epithelial cells and lung fibroblasts, as revealed by inhibition of TNFα-induced chemotactic cytokine and chemokine expression, along with inactivation of the MAPK and NFκB signalling pathways. MP also partially reversed the TGFβ-promoted EMT via downregulation of mesenchymal markers in A549 cells. Importantly, MP decreased the expression levels of fibrosis-related genes/proteins including collagen I, fibronectin, and αSMA; moreover, it suppressed collagen secretion and prevented myofibroblast differentiation in lung fibroblasts. These effects were mediated by FOXO3 stabilization through suppression of TGFβ-induced ERK1/2 phosphorylation. MP consistently protected mice from the onset and progression of bleomycin-induced pulmonary fibrosis.

CONCLUSION

This study explored the multifaceted roles of MP in counteracting the pathobiological processes of lung fibrosis. The results suggest that further evaluation of MP could yield candidate therapies for IPF.

5,7,3',4'-Tetramethoxyflavone suppresses TGF-β1-induced activation of murine fibroblasts in vitro and ameliorates bleomycin-induced pulmonary fibrosis in mice

OBJECTIVE

This study aimed to investigate the use of 5,7,3',4'-tetramethoxyflavone (TMF) to treat pulmonary fibrosis (PF), a chronic and fatal lung disease. In vitro and in vivo models were used to examine the impact of TMF on PF.

METHODS

NIH-3T3 (Mouse Embryonic Fibroblast) were exposed to transforming growth factor‑β1 (TGF-β1) and treated with or without TMF. Cell growth was assessed using the MTT method, and cell migration was evaluated with the scratch wound assay. Protein and messenger ribonucleic acid (mRNA) levels of extracellular matrix (ECM) genes were analyzed by western blotting and quantitative reverse transcription-polymerase chain reaction (RT-PCR), respectively. Downstream molecules affected by TGF-β1 were examined by western blotting. In vivo, mice with bleomycin-induced PF were treated with TMF, and lung tissues were analyzed with staining techniques.

RESULTS

The in vitro results showed that TMF had no significant impact on cell growth or migration. However, it effectively inhibited myofibroblast activation and ECM production induced by TGF-β1 in NIH-3T3 cells. This inhibition was achieved by suppressing various signaling pathways, including Smad, mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase/AKT (PI3K/AKT), and WNT/β-catenin. The in vivo experiments demonstrated the therapeutic potential of TMF in reducing PF induced by bleomycin in mice, and there was no significant liver or kidney toxicity observed.

CONCLUSION

These findings suggest that TMF has the potential to effectively inhibit myofibroblast activation and could be a promising treatment for PF. TMF achieves this inhibitory effect by targeting TGF-β1/Smad and non-Smad pathways.

C-type natriuretic peptide/cGMP/FoxO3 signaling attenuates hyperproliferation of pericytes from patients with pulmonary arterial hypertension

Pericyte dysfunction, with excessive migration, hyperproliferation, and differentiation into smooth muscle-like cells contributes to vascular remodeling in Pulmonary Arterial Hypertension (PAH). Augmented expression and action of growth factors trigger these pathological changes. Endogenous factors opposing such alterations are barely known. Here, we examine whether and how the endothelial hormone C-type natriuretic peptide (CNP), signaling through the cyclic guanosine monophosphate (cGMP) -producing guanylyl cyclase B (GC-B) receptor, attenuates the pericyte dysfunction observed in PAH. The results demonstrate that CNP/GC-B/cGMP signaling is preserved in lung pericytes from patients with PAH and prevents their growth factor-induced proliferation, migration, and transdifferentiation. The anti-proliferative effect of CNP is mediated by cGMP-dependent protein kinase I and inhibition of the Phosphoinositide 3-kinase (PI3K)/AKT pathway, ultimately leading to the nuclear stabilization and activation of the Forkhead Box O 3 (FoxO3) transcription factor. Augmentation of the CNP/GC-B/cGMP/FoxO3 signaling pathway might be a target for novel therapeutics in the field of PAH.

Autophagy in hepatic progenitor cells modulates exosomal miRNAs to inhibit liver fibrosis in schistosomiasis

Schistosoma infection is one of the major causes of liver fibrosis. Emerging roles of hepatic progenitor cells (HPCs) in the pathogenesis of liver fibrosis have been identified. Nevertheless, the precise mechanism underlying the role of HPCs in liver fibrosis in schistosomiasis remains unclear. This study examined how autophagy in HPCs affects schistosomiasis-induced liver fibrosis by modulating exosomal miRNAs. The activation of HPCs was verified by immunohistochemistry (IHC) and immunofluorescence (IF) staining in fibrotic liver from patients and mice with Schistosoma japonicum infection. By coculturing HPCs with hepatic stellate cells (HSCs) and assessing the autophagy level in HPCs by proteomic analysis and in vitro phenotypic assays, we found that impaired autophagy degradation in these activated HPCs was mediated by lysosomal dysfunction. Blocking autophagy by the autophagy inhibitor chloroquine (CQ) significantly diminished liver fibrosis and granuloma formation in S. japonicum-infected mice. HPC-secreted extracellular vehicles (EVs) were further isolated and studied by miRNA sequencing. miR-1306-3p, miR-493-3p, and miR-34a-5p were identified, and their distribution into EVs was inhibited due to impaired autophagy in HPCs, which contributed to suppressing HSC activation. In conclusion, we showed that the altered autophagy process upon HPC activation may prevent liver fibrosis by modulating exosomal miRNA release and inhibiting HSC activation in schistosomiasis. Targeting the autophagy degradation process may be a therapeutic strategy for liver fibrosis during Schistosoma infection.

lncRNA-mRNA Co-Expression and Regulation Analysis in Lung Fibroblasts from Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease marked by abnormal accumulation of extracellular matrix (ECM) due to dysregulated expression of various RNAs in pulmonary fibroblasts. This study utilized RNA-seq data meta-analysis to explore the regulatory network of hub long non-coding RNAs (lncRNAs) and messenger RNAs (mRNAs) in IPF fibroblasts. The meta-analysis unveiled 584 differentially expressed mRNAs (DEmRNA) and 75 differentially expressed lncRNAs (DElncRNA) in lung fibroblasts from IPF. Among these, BCL6, EFNB1, EPHB2, FOXO1, FOXO3, GNAI1, IRF4, PIK3R1, and RXRA were identified as hub mRNAs, while AC008708.1, AC091806.1, AL442071.1, FAM111A-DT, and LINC01989 were designated as hub lncRNAs. Functional characterization revealed involvement in TGF-β, PI3K, FOXO, and MAPK signaling pathways. Additionally, this study identified regulatory interactions between sequences of hub mRNAs and lncRNAs. In summary, the findings suggest that AC008708.1, AC091806.1, FAM111A-DT, LINC01989, and AL442071.1 lncRNAs can regulate BCL6, EFNB1, EPHB2, FOXO1, FOXO3, GNAI1, IRF4, PIK3R1, and RXRA mRNAs in fibroblasts bearing IPF and contribute to fibrosis by modulating crucial signaling pathways such as FoxO signaling, chemical carcinogenesis, longevity regulatory pathways, non-small cell lung cancer, and AMPK signaling pathways.

Perturbations in inflammatory pathways are associated with shortness of breath profiles in oncology patients receiving chemotherapy

PURPOSE

One plausible mechanistic hypothesis is the potential contribution of inflammatory mechanisms to shortness of breath. This study was aimed to evaluate for associations between the occurrence of shortness of breath and perturbations in inflammatory pathways.

METHODS

Patients with cancer reported the occurrence of shortness of breath six times over two cycles of chemotherapy. Latent class analysis was used to identify subgroups of patients with distinct shortness of breath occurrence profiles (i.e., none (70.5%), decreasing (8.2%), increasing (7.8%), high (13.5%)). Using an extreme phenotype approach, whole transcriptome differential gene expression and pathway impact analyses were performed to evaluate for perturbed signaling pathways associated with shortness of breath between the none and high classes. Two independent samples (RNA-sequencing (n = 293) and microarray (n = 295) methodologies) were evaluated. Fisher's combined probability method was used to combine these results to obtain a global test of the null hypothesis. In addition, an unweighted knowledge network was created using the specific pathway maps to evaluate for interconnections among these pathways.

RESULTS

Twenty-nine Kyoto Encyclopedia of Genes and Genomes inflammatory signaling pathways were perturbed. The mitogen-activated protein kinase signaling pathway node had the highest closeness, betweenness, and degree scores. In addition, five common respiratory disease-related pathways, that may share mechanisms with cancer-related shortness of breath, were perturbed.

CONCLUSIONS

Findings provide preliminary support for the hypothesis that inflammation contribute to the occurrence of shortness of breath in patients with cancer. In addition, the mechanisms that underlie shortness of breath in oncology patients may be similar to other respiratory diseases.

Improvements in lung function following vitamin C supplementation to pregnant smokers are associated with buccal DNA methylation at 5 years of age

BACKGROUND

We previously reported in the "Vitamin C to Decrease the Effects of Smoking in Pregnancy on Infant Lung Function" randomized clinical trial (RCT) that vitamin C (500 mg/day) supplementation to pregnant smokers is associated with improved respiratory outcomes that persist through 5 years of age. The objective of this study was to assess whether buccal cell DNA methylation (DNAm), as a surrogate for airway epithelium, is associated with vitamin C supplementation, improved lung function, and decreased occurrence of wheeze.

METHODS

We conducted epigenome-wide association studies (EWAS) using Infinium MethylationEPIC arrays and buccal DNAm from 158 subjects (80 placebo; 78 vitamin C) with pulmonary function testing (PFT) performed at the 5-year visit. EWAS were performed on (1) vitamin C treatment, (2) forced expiratory flow between 25 and 75% of expired volume (FEF25-75), and (3) offspring wheeze. Models were adjusted for sex, race, study site, gestational age at randomization (≤ OR > 18 weeks), proportion of epithelial cells, and latent covariates in addition to child length at PFT in EWAS for FEF25-75. We considered FDR p < 0.05 as genome-wide significant and nominal p < 0.001 as candidates for downstream analyses. Buccal DNAm measured in a subset of subjects at birth and near 1 year of age was used to determine whether DNAm signatures originated in utero, or emerged with age.

RESULTS

Vitamin C treatment was associated with 457 FDR significant (q < 0.05) differentially methylated CpGs (DMCs; 236 hypermethylated; 221 hypomethylated) and 53 differentially methylated regions (DMRs; 26 hyper; 27 hypo) at 5 years of age. FEF25-75 was associated with one FDR significant DMC (cg05814800), 1,468 candidate DMCs (p < 0.001), and 44 DMRs. Current wheeze was associated with 0 FDR-DMCs, 782 candidate DMCs, and 19 DMRs (p < 0.001). In 365/457 vitamin C FDR significant DMCs at 5 years of age, there was no significant interaction between time and treatment.

CONCLUSIONS

Vitamin C supplementation to pregnant smokers is associated with buccal DNA methylation in offspring at 5 years of age, and most methylation signatures appear to be persistent from the prenatal period. Buccal methylation at 5 years was also associated with current lung function and occurrence of wheeze, and these functionally associated loci are enriched for vitamin C associated loci. Clinical trial registration ClinicalTrials.gov, NCT01723696 and NCT03203603.

Generic model to unravel the deeper insights of viral infections: an empirical application of evolutionary graph coloring in computational network biology

PURPOSE

Graph coloring approach has emerged as a valuable problem-solving tool for both theoretical and practical aspects across various scientific disciplines, including biology. In this study, we demonstrate the graph coloring's effectiveness in computational network biology, more precisely in analyzing protein-protein interaction (PPI) networks to gain insights about the viral infections and its consequences on human health. Accordingly, we propose a generic model that can highlight important hub proteins of virus-associated disease manifestations, changes in disease-associated biological pathways, potential drug targets and respective drugs. We test our model on SARS-CoV-2 infection, a highly transmissible virus responsible for the COVID-19 pandemic. The pandemic took significant human lives, causing severe respiratory illnesses and exhibiting various symptoms ranging from fever and cough to gastrointestinal, cardiac, renal, neurological, and other manifestations.

METHODS

To investigate the underlying mechanisms of SARS-CoV-2 infection-induced dysregulation of human pathobiology, we construct a two-level PPI network and employed a differential evolution-based graph coloring (DEGCP) algorithm to identify critical hub proteins that might serve as potential targets for resolving the associated issues. Initially, we concentrate on the direct human interactors of SARS-CoV-2 proteins to construct the first-level PPI network and subsequently applied the DEGCP algorithm to identify essential hub proteins within this network. We then build a second-level PPI network by incorporating the next-level human interactors of the first-level hub proteins and use the DEGCP algorithm to predict the second level of hub proteins.

RESULTS

We first identify the potential crucial hub proteins associated with SARS-CoV-2 infection at different levels. Through comprehensive analysis, we then investigate the cellular localization, interactions with other viral families, involvement in biological pathways and processes, functional attributes, gene regulation capabilities as transcription factors, and their associations with disease-associated symptoms of these identified hub proteins. Our findings highlight the significance of these hub proteins and their intricate connections with disease pathophysiology. Furthermore, we predict potential drug targets among the hub proteins and identify specific drugs that hold promise in preventing or treating SARS-CoV-2 infection and its consequences.

CONCLUSION

Our generic model demonstrates the effectiveness of DEGCP algorithm in analyzing biological PPI networks, provides valuable insights into disease biology, and offers a basis for developing novel therapeutic strategies for other viral infections that may cause future pandemic.

Maimendong decoction regulates M2 macrophage polarization to suppress pulmonary fibrosis via PI3K/Akt/FOXO3a signalling pathway-mediated fibroblast activation

ETHNOPHARMACOLOGICAL RELEVANCE

Mai Men Dong decoction (MMDD), a traditional Chinese medicine formula, is relevant to ethnopharmacology due to its constituents and therapeutic properties. The formula contains herbs like Ophiopogon japonicus (Thunb.) Ker Gawl., Pinellia ternata (Thunb.) Makino, Panax ginseng C.A.Mey, Glycyrrhiza uralensis Fisch, and Ziziphus jujuba Mill, Oryza sativa L., which have been used for centuries in Chinese medicine. These herbs provide a comprehensive approach to treating respiratory conditions by addressing dryness, cough, and phlegm. Ethnopharmacological studies have explored the scientific basis of these herbs and identified active compounds that contribute to their medicinal effects. The traditional usage of MMDD by different ethnic groups reflects their knowledge and experiences. Examining this formula contributes to the understanding and development of ethnopharmacology.

AIM OF THE STUDY

In the case of pulmonary fibrosis (PF), treating it can be challenging due to the limited treatment options available. This study aimed to assess the potential of MMDD as a treatment for PF by targeting macrophages and the PI3K/Akt/FOXO3a signaling pathway.

MATERIALS AND METHODS

In a mouse model of PF, we investigated the effects of MMDD on inflammation, fibrosis, and M2 macrophage infiltration in lung tissue. Additionally, we examined the modulation of pro-fibrotic factors and key proteins in the PI3K/Akt/FOXO3a pathway. In vitro experiments involved inducing M2-type macrophages and assessing the impact of MMDD on fibroblast activation and the PI3K/Akt/FOXO3a pathway.

RESULTS

Results demonstrated that MMDD improved weight, reduced inflammation, and inhibited M2 macrophage infiltration in mouse lung tissue. It downregulated pro-fibrotic factors, such as TGF-β1 and PDGF-RB, as well as markers of fibroblast activation. MMDD also exhibited regulatory effects on key proteins in the PI3K/Akt/FOXO3a signaling pathway.

CONCLUSIONS

MMDD inhibited M2 macrophage polarization and released profibrotic factors that inhibited pulmonary fibrosis. As a result, the PI3K/Akt/FOXO3a signaling pathway is suppressed. MMDD is proving to be a successful treatment for PF. However, further research is needed to validate its effectiveness in clinical practice.

Unraveling FOXO3a and USP18 Functions in Idiopathic Pulmonary Fibrosis through Single-Cell RNA Sequencing of Mouse and Human Lungs

Background  Idiopathic pulmonary fibrosis (IPF) is identified as a chronic, progressive lung disease, predominantly marked by enhanced fibroblast proliferation and excessive deposition of extracellular matrix. The intricate interactions between diverse molecular pathways in fibroblasts play a crucial role in driving the pathogenesis of IPF. Methods  This research is focused on elucidating the roles of FOXO3a, a transcription factor, and USP18, a ubiquitin-specific protease, in modulating fibroblast functionality in the context of IPF. FOXO3a is well-known for its regulatory effects on cellular responses, including apoptosis and oxidative stress, while USP18 is generally associated with protein deubiquitination. Results  Our findings highlight that FOXO3a acts as a critical regulator in controlling fibroblast activation and differentiation, illustrating its vital role in the pathology of IPF. Conversely, USP18 seems to promote fibroblast proliferation and imparts resistance to apoptosis, thereby contributing to the exacerbation of fibrotic processes. The synergistic dysregulation of both FOXO3a and USP18 in fibroblasts was found to significantly contribute to the fibrotic alterations characteristic of IPF. Conclusion  Deciphering the complex molecular interactions between FOXO3a and USP18 in fibroblasts provides a deeper understanding of IPF pathogenesis and unveils novel therapeutic avenues, offering a promising potential for not just halting but potentially reversing the progression of this debilitating disease.

Small-Molecule Activation of Protein Phosphatase 2A Counters Bleomycin-Induced Fibrosis in Mice

The activity of protein phosphatase 2A (PP2A), a serine-threonine phosphatase, is reduced in the lung fibroblasts of idiopathic pulmonary fibrosis (IPF) patients. The objective of this study was to determine whether the reactivation of PP2A could reduce fibrosis and preserve the pulmonary function in a bleomycin (BLM) mouse model. Here, we present a new class of direct small-molecule PP2A activators, diarylmethyl-pyran-sulfonamide, exemplified by ATUX-1215. ATUX-1215 has improved metabolic stability and bioavailability compared to our previously described PP2A activators. Primary human lung fibroblasts were exposed to ATUX-1215 and an older generation PP2A activator in combination with TGFβ. ATUX-1215 treatment enhanced the PP2A activity, reduced the phosphorylation of ERK and JNK, and reduced the TGFβ-induced expression of ACTA2, FN1, COL1A1, and COL3A1. C57BL/6J mice were administered 5 mg/kg ATUX-1215 daily following intratracheal instillation of BLM. Three weeks later, forced oscillation and expiratory measurements were performed using the Scireq Flexivent System. ATUX-1215 prevented BLM-induced lung physiology changes, including the preservation of normal PV loop, compliance, tissue elastance, and forced vital capacity. PP2A activity was enhanced with ATUX-1215 and reduced collagen deposition within the lungs. ATUX-1215 also prevented the BLM induction of Acta2, Ccn2, and Fn1 gene expression. Treatment with ATUX-1215 reduced the phosphorylation of ERK, p38, JNK, and Akt and the secretion of IL-12p70, GM-CSF, and IL1α in BLM-treated animals. Delayed treatment with ATUX-1215 was also observed to slow the progression of lung fibrosis. In conclusion, our study indicates that the decrease in PP2A activity, which occurs in fibroblasts from the lungs of IPF subjects, could be restored with ATUX-1215 administration as an antifibrotic agent.

A genomic perspective of the aging human and mouse lung with a focus on immune response and cellular senescence

BACKGROUND

The aging lung is a complex process and influenced by various stressors, especially airborne pathogens and xenobiotics. Additionally, a lifetime exposure to antigens results in structural and functional changes of the lung; yet an understanding of the cell type specific responses remains elusive. To gain insight into age-related changes in lung function and inflammaging, we evaluated 89 mouse and 414 individual human lung genomic data sets with a focus on genes mechanistically linked to extracellular matrix (ECM), cellular senescence, immune response and pulmonary surfactant, and we interrogated single cell RNAseq data to fingerprint cell type specific changes.

RESULTS

We identified 117 and 68 mouse and human genes linked to ECM remodeling which accounted for 46% and 27%, respectively of all ECM coding genes. Furthermore, we identified 73 and 31 mouse and human genes linked to cellular senescence, and the majority code for the senescence associated secretory phenotype. These cytokines, chemokines and growth factors are primarily secreted by macrophages and fibroblasts. Single-cell RNAseq data confirmed age-related induced expression of marker genes of macrophages, neutrophil, eosinophil, dendritic, NK-, CD4+, CD8+-T and B cells in the lung of aged mice. This included the highly significant regulation of 20 genes coding for the CD3-T-cell receptor complex. Conversely, for the human lung we primarily observed macrophage and CD4+ and CD8+ marker genes as changed with age. Additionally, we noted an age-related induced expression of marker genes for mouse basal, ciliated, club and goblet cells, while for the human lung, fibroblasts and myofibroblasts marker genes increased with age. Therefore, we infer a change in cellular activity of these cell types with age. Furthermore, we identified predominantly repressed expression of surfactant coding genes, especially the surfactant transporter Abca3, thus highlighting remodeling of surfactant lipids with implications for the production of inflammatory lipids and immune response.

CONCLUSION

We report the genomic landscape of the aging lung and provide a rationale for its growing stiffness and age-related inflammation. By comparing the mouse and human pulmonary genome, we identified important differences between the two species and highlight the complex interplay of inflammaging, senescence and the link to ECM remodeling in healthy but aged individuals.

Astragaloside IV protects against lung injury and pulmonary fibrosis in COPD by targeting GTP-GDP domain of RAS and downregulating the RAS/RAF/FoxO signaling pathway

BACKGROUND

Pulmonary fibrosis is a chronic progressive interstitial lung disease characterized by the replacement of lung parenchyma with fibrous scar tissue, usually as the final stage of lung injury like COPD. Astragaloside IV (AST), a bioactive compound found in the Astragalus membranaceus (Fisch.) used in traditional Chinese medicine, has been shown to improve pulmonary function and exhibit anti-pulmonary fibrosis effects. However, the exact molecular mechanisms through which it combats pulmonary fibrosis, especially in COPD, remain unclear.

PURPOSE

This study aimed to identify the potential therapeutic target and molecular mechanisms for AST in improving lung injury especially treating COPD type pulmonary fibrosis both in vivo and in vitro.

METHODS

Multi lung injury models were established in mice using lipopolysaccharide (LPS), cigarette smoke (CS), or LPS plus CS to simulate the processes of pulmonary fibrosis in COPD. The effect of AST on lung function protection was evaluated, and proteomic and metabolomic analysis were applied to identify the signaling pathway affected by AST and to find potential targets of AST. The interaction between AST and wild-type and mutant RAS proteins was studied. The RAS/RAF/FoxO signaling pathway was stimulated in BEAS-2B cells and in mice lung tissues by LPS plus CS to investigate the anti-pulmonary fibrosis mechanism of AST analyzed by western blotting. The regulatory effects of AST on the RAS/RAF/FoxO pathway dependent on RAS were further confirmed using RAS siRNA.

RESULTS

RAS was predicted and identified as the target protein of AST in anti-pulmonary fibrosis in COPD and improving lung function. The administration of AST was observed to impede the conversion of fibroblasts into myofibroblasts, reduce the manifestation of inflammatory factors and extracellular matrix, and hinder the activation of epithelial mesenchymal transition (EMT). Furthermore, AST significantly suppressed the RAS/RAF/FoxO signaling pathway in both in vitro and in vivo settings.

CONCLUSION

AST exhibited lung function protection and anti-pulmonary fibrosis effect by inhibiting the GTP-GDP domain of RAS, which downregulated the RAS/RAF/FoxO signaling pathway. This study revealed AST as a natural candidate molecule for the protection of pulmonary fibrosis in COPD.

Identifying potential biomarkers of idiopathic pulmonary fibrosis through machine learning analysis

Idiopathic pulmonary fibrosis (IPF) is the most common and serious type of idiopathic interstitial pneumonia, characterized by chronic, progressive, and low survival rates, while unknown disease etiology. Until recently, patients with idiopathic pulmonary fibrosis have a poor prognosis, high mortality, and limited treatment options, due to the lack of effective early diagnostic and prognostic tools. Therefore, we aimed to identify biomarkers for idiopathic pulmonary fibrosis based on multiple machine-learning approaches and to evaluate the role of immune infiltration in the disease. The gene expression profile and its corresponding clinical data of idiopathic pulmonary fibrosis patients were downloaded from Gene Expression Omnibus (GEO) database. Next, the differentially expressed genes (DEGs) with the threshold of FDR < 0.05 and |log2 foldchange (FC)| > 0.585 were analyzed via R package "DESeq2" and GO enrichment and KEGG pathways were run in R software. Then, least absolute shrinkage and selection operator (LASSO) logistic regression, support vector machine-recursive feature elimination (SVM-RFE) and random forest (RF) algorithms were combined to screen the key potential biomarkers of idiopathic pulmonary fibrosis. The diagnostic performance of these biomarkers was evaluated through receiver operating characteristic (ROC) curves. Moreover, the CIBERSORT algorithm was employed to assess the infiltration of immune cells and the relationship between the infiltrating immune cells and the biomarkers. Finally, we sought to understand the potential pathogenic role of the biomarker (SLAIN1) in idiopathic pulmonary fibrosis using a mouse model and cellular model. A total of 3658 differentially expressed genes of idiopathic pulmonary fibrosis were identified, including 2359 upregulated genes and 1299 downregulated genes. FHL2, HPCAL1, RNF182, and SLAIN1 were identified as biomarkers of idiopathic pulmonary fibrosis using LASSO logistic regression, RF, and SVM-RFE algorithms. The ROC curves confirmed the predictive accuracy of these biomarkers both in the training set and test set. Immune cell infiltration analysis suggested that patients with idiopathic pulmonary fibrosis had a higher level of B cells memory, Plasma cells, T cells CD8, T cells follicular helper, T cells regulatory (Tregs), Macrophages M0, and Mast cells resting compared with the control group. Correlation analysis demonstrated that FHL2 was significantly associated with the infiltrating immune cells. qPCR and western blotting analysis suggested that SLAIN1 might be a signature for the diagnosis of idiopathic pulmonary fibrosis. In this study, we identified four potential biomarkers (FHL2, HPCAL1, RNF182, and SLAIN1) and evaluated the potential pathogenic role of SLAIN1 in idiopathic pulmonary fibrosis. These findings may have great significance in guiding the understanding of disease mechanisms and potential therapeutic targets in idiopathic pulmonary fibrosis.

Mechanism of myocardial fibrosis regulation by IGF-1R in atrial fibrillation through the PI3K/Akt/FoxO3a pathway

Atrial structural remodeling takes on a critical significance to the occurrence and maintenance of atrial fibrillation (AF). As revealed by recent data, insulin-like growth factor-1 receptor (IGF-1R) plays a certain role in tissue fibrosis. In this study, the mechanism of IGF-1R in atrial structural remodeling was examined based on in vivo and in vitro experiments. First, cluster analysis of AF hub genes was conducted, and then the molecular mechanism was proposed by which IGF-1R regulates myocardial fibrosis via the PI3K/Akt/FoxO3a pathway. Subsequently, the mentioned mechanism was verified in human cardiac fibroblasts (HCFs) and rats transduced with IGF-1 overexpression type 9 adeno-associated viruses. The results indicated that IGF-1R activation up-regulated collagen Ⅰ protein expression and Akt phosphorylation in HCFs and rat atrium. The administration of LY294002 reversed the above phenomenon, improved the shortening of atrial effective refractory period, and reduced the increased incidence of AF and atrial fibrosis in rats. The transfection of FoxO3a siRNA reduced the anti-fibrotic effect of LY294002 in HCFs. The above data revealed that activation of IGF-1R takes on a vital significance to atrial structural remodeling by facilitating myocardial fibrosis and expediting the occurrence and maintenance of AF through the regulation of the PI3K/Akt/FoxO3a signaling pathway.

FOXO3 regulates Smad3 and Smad7 through SPON1 circular RNA to inhibit idiopathic pulmonary fibrosis

Forkhead box protein O3 (FOXO3) has good inhibition ability toward fibroblast activation and extracellular matrix, especially for the treatment of idiopathic pulmonary fibrosis. How FOXO3 regulates pulmonary fibrosis remains unclear. In this study, we reported that FOXO3 had binding sequences with F-spondin 1 (SPON1) promoter, which can activate its transcription and selectively promote the expression of SPON1 circRNA (circSPON1) but not mRNA expression. We further demonstrated that circSPON1 was involved in the extracellular matrix deposition of HFL1. In the cytoplasm, circSPON1 directly interacted with TGF-β1-induced Smad3 and inhibited the activation of fibroblasts by inhibiting nuclear translocation. Moreover, circSPON1 bound to miR-942-5p and miR-520f-3p that interfered with Smad7 mRNA and promoted Smad7 expression. This study revealed the mechanism of FOXO3-regulated circSPON1 in the development of pulmonary fibrosis. Potential therapeutic targets and new insights into the diagnosis and treatment of idiopathic pulmonary fibrosis based on circRNA were also provided.

Targeting TGF-β/periostin signaling by sesamol ameliorates pulmonary fibrosis and improves lung function and survival

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive disorder that severely impairs lung function, by increasing lung stiffness. Sesamol, a phenolic Phyto-molecule isolated from sesame seeds, possess a rich source of protein and is known to have extensive nutritional and health effects. Here we investigated the effect of sesamol on TGF-β/periostin-induced fibroblast differentiation in in vitro and bleomycin-induced pulmonary fibrosis in an in vivo model. Our results demonstrated that activation of (DHLF, LL29, NHLF and A549) cells with TGF-β, elevates the epithelial to mesenchymal, extracellular matrix, and collagen deposition and periostin signaling marker's expression, further treatment with sesamol attenuated these markers significantly. In addition, sesamol treatment improved the TGF-β-induced contraction and migration of cells. Mechanistic studies showed that activation of IPF cells with periostin increased the TGF-β signaling and treatment with sesamol significantly abrogated the periostin-induced TGF-β activation and its downstream fibrotic marker's expression. In in vivo, sesamol treatment attenuated the lung inflammation, infiltration of cells, wall thickening and the formation of fibrous bands significantly in BLM-induced fibrosis rats. Molecular studies revealed that sesamol treatment reduced the bleomycin-induced fibrotic, inflammatory, apoptotic marker's expression by modulating the TGF-β/periostin crosstalk signaling in a dose-dependent manner. Further, treatment with sesamol dramatically improved lung function and decreased mortality. Our study first time reports the sesamol's inhibitory effects on periostin signalling. Collectively, our study demonstrated that periostin and TGF-β seem to work in a positive-feedback loop, inducing the other, therefore, targeting TGF-β/periostin signaling may provide a better therapeutic approach against IPF and other fibrotic disorders.

Construction of a TFs-miRNA-mRNA network related to idiopathic pulmonary fibrosis

Background

The transcription factors (TFs)-microRNA (miRNA)-messenger RNA (mRNA) network plays an important role in a variety of diseases. However, the relationship between the TFs-miRNA-mRNA network and idiopathic pulmonary fibrosis (IPF) remains unclear.

Methods

The GSE110147 and GSE53845 datasets from the Gene Expression Omnibus (GEO) database were used to process differentially expressed genes (DEGs) analysis, gene set enrichment analysis (GSEA), weighted gene co-expression network analysis (WGCNA), as well as Gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. The GSE13316 dataset was used to perform differentially expressed miRNAs (DEMs) analysis and TFs prediction. Finally, a TFs-miRNA-mRNA network related to IPF was constructed, and its function was evaluated by Gene Ontology (GO) and KEGG analyses. Also, 19 TFs in the network were verified by quantitative real time polymerase chain reaction (qRT-PCR).

Results

Through our analysis, 53 DEMs and 2,630 DEGs were screened. The GSEA results suggested these genes were mainly related to protein digestion and absorption. The WGCNA results showed that these DEGs were divided into eight modules, and the GO and KEGG analyses results of blue module genes showed that these 86 blue module genes were mainly enriched in cilium assembly and cilium organization. Moreover, a TFs-miRNA-mRNA network comprising 25 TFs, 11 miRNAs, and 60 mRNAs was constructed. Ultimately, the functional enrichment analysis showed that the TFs-miRNA-mRNA network was mainly related to the cell cycle and the phosphatidylinositol 3 kinase-protein kinase B (PI3K-Akt) signaling pathway. Furthermore, experimental verification of the TFs showed that ARNTL, TRIM28, EZH2, BCOR, and ASXL1 were sufficiently up-regulated in the transforming growth factor (TGF)-β1 treatment groups, while BCL6, BHLHE40, FOXA1, and EGR1 were significantly down-regulated.

Conclusions

The novel TFs-miRNA-mRNA network that we constructed could provide new insights into the underlying molecular mechanisms of IPF. ARNTL, TRIM28, EZH2, BCOR, ASXL1, BCL6, BHLHE40, FOXA1, and EGR1 may play important roles in IPF and become effective biomarkers for diagnosis and treatment.

FoxO3 Regulates the Progress and Development of Aging and Aging-Related Diseases

Aging is an inevitable risk factor for many diseases, including cardiovascular diseases, neurodegenerative diseases, cancer, and diabetes. Investigation into the molecular mechanisms involved in aging and longevity will benefit the treatment of age-dependent diseases and the development of preventative medicine for agingrelated diseases. Current evidence has revealed that FoxO3, encoding the transcription factor (FoxO)3, a key transcription factor that integrates different stimuli in the intrinsic and extrinsic pathways and is involved in cell differentiation, protein homeostasis, stress resistance and stem cell status, plays a regulatory role in longevity and in age-related diseases. However, the precise mechanisms by which the FoxO3 transcription factor modulates aging and promotes longevity have been unclear until now. Here, we provide a brief overview of the mechanisms by which FoxO3 mediates signaling in pathways involved in aging and aging-related diseases, as well as the current knowledge on the role of the FoxO3 transcription factor in the human lifespan and its clinical prospects. Ultimately, we conclude that FoxO3 signaling pathways, including upstream and downstream molecules, may be underlying therapeutic targets in aging and age-related diseases.

Molecular Regulation of Heme Oxygenase-1 Expression by E2F Transcription Factor 2 in Lung Fibroblast Cells: Relevance to Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal chronic lung disease. Heme oxygenase-1 (HMOX1/HO-1) is an enzyme that catalyzes the degradation of heme. The role of HO-1 in the pathogenesis of IPF has been studied; however, the molecular regulation of HO-1 and its role in IPF are still unclear. In this study, we found that HO-1 protein levels significantly increased in lung myofibroblasts in IPF patients and in lungs in a murine model of bleomycin-induced lung fibrosis. In addition, we observed that administration of a E2F transcription factor inhibitor elevated HO-1 mRNA and protein levels in lung fibroblasts. Downregulation of E2F2 by siRNA transfection increased HO-1 mRNA and protein levels, while overexpression of E2F2 reduced HO-1 levels. However, overexpression of E2F2 did not alter hemin-induced HO-1 protein levels. Furthermore, modulation of HO-1 levels regulated TGF-β1-induced myofibroblast differentiation without altering the phosphorylation of Smad2/3 in lung fibroblast cells. Moreover, the phosphorylation of protein kinase B (Akt) was significantly upregulated in HO-1-depleted lung fibroblast cells. In summary, this study demonstrated that E2F2 regulates the baseline expression of HO-1, but has no effect on modulating HO-1 expression by hemin. Finally, elevated HO-1 expression contributes to the TGF-β1-induced lung myofibroblast differentiation through the activation of the serine/threonine kinase AKT pathway. Overall, our findings suggest that targeting E2F2/HO-1 might be a new therapeutic strategy to treat fibrotic diseases such as IPF.

Fibrocytes boost tumor-supportive phenotypic switches in the lung cancer niche via the endothelin system

Fibrocytes are bone marrow-derived monocytic cells implicated in wound healing. Here, we identify their role in lung cancer progression/ metastasis. Selective manipulation of fibrocytes in mouse lung tumor models documents the central role of fibrocytes in boosting niche features and enhancing metastasis. Importantly, lung cancer patients show increased number of circulating fibrocytes and marked fibrocyte accumulation in the cancer niche. Using double and triple co-culture systems with human lung cancer cells, fibrocytes, macrophages and endothelial cells, we substantiate the central features of cancer-supporting niche: enhanced cancer cell proliferation and migration, macrophage activation, augmented endothelial cell sprouting and fibrocyte maturation. Upregulation of endothelin and its receptors are noted, and dual endothelin receptor blockade suppresses all cancer-supportive phenotypic alterations via acting on fibrocyte interaction with the cancer niche. We thus provide evidence for a crucial role of fibrocytes in lung cancer progression and metastasis, suggesting targets for treatment strategies.

SRPK1 promotes sepsis-induced acute lung injury via regulating PI3K/AKT/FOXO3 signaling

OBJECTIVE

Sepsis is the most common cause of death in intensive care unit. Moreover, sepsis is the leading cause of acute lung injury (ALI). Serine-arginine protein kinase 1 (SRPK1) was demonstrated to promote the development of ALI. However, the potentials of SRPK1 in sepsis-induced ALI are still unknown. This study aimed to investigate the potentials of SRPK1 in sepsis-induced ALI and the underlying mechanisms.

METHODS

Cecal ligation and puncture (CLP) was performed to establish sepsis-induced ALI model in vivo. Primary human pulmonary microvascular endothelial cells (HPMECs) were exposed to lipopolysaccharide (LPS) to construct sepsis-induced ALI model in vitro. Gene expression was detected using western blot and qRT-PCR. The interaction between forkhead box O3 (FOXO3) and NOD-like receptor thermal protein domain associated protein 3 (NLRP3) was detected using luciferase and Chromatin immunoprecipitation (ChIP) assay. Cellular functions were CCK-8, colony formation, PI staining, and flow cytometry assay.

RESULTS

SRPK1 was downregulated in patients with sepsis-induced ALI. Overexpression of SRPK1 suppressed the pyroptosis of HPMECs as well as promoted cell proliferation. Additionally, SRPK1 overexpression alleviated sepsis-induced ALI in vivo. SRPK1 activated phosphatidylinositol3-kinase (PI3K) signaling pathways. Blocking the activation of PI3K degraded the cellular functions of HPMECs. Moreover, FOXO3 transcriptionally inactivated NLRP3 and suppressed its mRNA and protein expression.

CONCLUSION

Taken together, SRPK1 suppressed sepsis-induced ALI via regulating PI3K/AKT/FOXO3/NLRP3 signaling. SRPK1 may be the potential biomarker for sepsis-induced ALI.

Airway remodeling: The Drosophila model permits a purely epithelial perspective

Airway remodeling is an umbrella term for structural changes in the conducting airways that occur in chronic inflammatory lung diseases such as asthma or chronic obstructive pulmonary disease (COPD). The pathobiology of remodeling involves multiple mesenchymal and lymphoid cell types and finally leads to a variety of hardly reversible changes such as hyperplasia of goblet cells, thickening of the reticular basement membrane, deposition of collagen, peribronchial fibrosis, angiogenesis and hyperplasia of bronchial smooth muscle cells. In order to develop solutions for prevention or innovative therapies, these complex processes must be understood in detail which requires their deconstruction into individual building blocks. In the present manuscript we therefore focus on the role of the airway epithelium and introduce Drosophila melanogaster as a model. The simple architecture of the flies’ airways as well as the lack of adaptive immunity allows to focus exclusively on the importance of the epithelium for the remodeling processes. We will review and discuss genetic and environmentally induced changes in epithelial structures and molecular responses and propose an integrated framework of research for the future.

Research Progress of Fibroblast Growth Factor 21 in Fibrotic Diseases

Fibrosis is a common pathological outcome of chronic injuries, characterized by excessive deposition of extracellular matrix components in organs, as seen in most chronic inflammatory diseases. At present, there is an increasing tendency of the morbidity and mortality of diseases caused by fibrosis, but the treatment measures for fibrosis are still limited. Fibroblast growth factor 21 (FGF21) belongs to the FGF19 subfamily, which also has the name endocrine FGFs because of their endocrine manner. In recent years, it has been found that plasma FGF21 level is significantly correlated with fibrosis progression. Furthermore, there is evidence that FGF21 has a pronounced antifibrotic effect in a variety of fibrotic diseases. This review summarizes the biological effects of FGF21 and discusses what is currently known about this factor and fibrosis disease, highlighting emerging insights that warrant further research.

MicroRNA Cross-Involvement in Acne Vulgaris and Hidradenitis Suppurativa: A Literature Review

Acne Vulgaris (AV) and Hidradenitis suppurativa (HS) are common chronic inflammatory skin conditions that affect the follicular units that often coexist or are involved in differential diagnoses. Inflammation in both these diseases may result from shared pathways, which may partially explain their frequent coexistence. MicroRNAs (miRNAs) are a class of endogenous, short, non-protein coding, gene-silencing or promoting RNAs that may promote various inflammatory diseases. This narrative review investigates the current knowledge regarding miRNAs and their link to AV and HS. The aim is to examine the role of these molecules in the pathogenesis of AV and HS and to identify possible common miRNAs that could explain the similar characteristics of these two diseases. Five miRNA (miR-155 miR-223-, miR-21, and miRNA-146a) levels were found to be altered in both HS and AV. These miRNAs are related to pathogenetic aspects common to both pathologies, such as the regulation of the innate immune response, regulation of the Th1/Th17 axis, and fibrosis processes that induce scar formation. This review provides a starting point for further studies aimed at investigating the role of miRNAs in AV and HS for their possible use as diagnostic-therapeutic targets.

Targeting Chitinase 1 and Chitinase 3-Like 1 as Novel Therapeutic Strategy of Pulmonary Fibrosis

Chitinase 1 (CHIT1) and chitinase 3-like-1 (CHI3L1), two representative members of 18-Glycosyl hydrolases family, are significantly implicated in the pathogenesis of various human diseases characterized by inflammation and remodeling. Notably, dysregulated expression of CHIT1 and CHI3L1 was noted in the patients with pulmonary fibrosis and their levels were inversely correlated with clinical outcome of the patients. CHIT1 and CHI3L1, mainly expressed in alveolar macrophages, regulate profibrotic macrophage activation, fibroblast proliferation and myofibroblast transformation, and TGF-β signaling and effector function. Although the mechanism or the pathways that CHIT1 and CHI3L1 use to regulate pulmonary fibrosis have not been fully understood yet, these studies identify CHIT1 and CHI3L1 as significant modulators of fibroproliferative responses leading to persistent and progressive pulmonary fibrosis. These studies suggest a possibility that CHIT1 and CHI3L1 could be reasonable therapeutic targets to intervene or reverse established pulmonary fibrosis. In this review, we will discuss specific roles and regulatory mechanisms of CHIT1 and CHI3L1 in profibrotic cell and tissue responses as novel therapeutic targets of pulmonary fibrosis.

Noncanonical HIPPO/MST Signaling via BUB3 and FOXO Drives Pulmonary Vascular Cell Growth and Survival

RATIONALE

The MSTs (mammalian Ste20-like kinases) 1/2 are members of the HIPPO pathway that act as growth suppressors in adult proliferative diseases. Pulmonary arterial hypertension (PAH) manifests by increased proliferation and survival of pulmonary vascular cells in small PAs, pulmonary vascular remodeling, and the rise of pulmonary arterial pressure. The role of MST1/2 in PAH is currently unknown.

OBJECTIVE

To investigate the roles and mechanisms of the action of MST1 and MST2 in PAH.

METHODS AND RESULTS

Using early-passage pulmonary vascular cells from PAH and nondiseased lungs and mice with smooth muscle-specific tamoxifen-inducible Mst1/2 knockdown, we found that, in contrast to canonical antiproliferative/proapoptotic roles, MST1/2 act as proproliferative/prosurvival molecules in human PAH pulmonary arterial vascular smooth muscle cells and pulmonary arterial adventitial fibroblasts and support established pulmonary vascular remodeling and pulmonary hypertension in mice with SU5416/hypoxia-induced pulmonary hypertension. By using unbiased proteomic analysis, gain- and loss-of function approaches, and pharmacological inhibition of MST1/2 kinase activity by XMU-MP-1, we next evaluated mechanisms of regulation and function of MST1/2 in PAH pulmonary vascular cells. We found that, in PAH pulmonary arterial adventitial fibroblasts, the proproliferative function of MST1/2 is caused by IL-6-dependent MST1/2 overexpression, which induces PSMC6-dependent downregulation of forkhead homeobox type O 3 and hyperproliferation. In PAH pulmonary arterial vascular smooth muscle cells, MST1/2 acted via forming a disease-specific interaction with BUB3 and supported ECM (extracellular matrix)- and USP10-dependent BUB3 accumulation, upregulation of Akt-mTORC1, cell proliferation, and survival. Supporting our in vitro observations, smooth muscle-specific Mst1/2 knockdown halted upregulation of Akt-mTORC1 in small muscular PAs of mice with SU5416/hypoxia-induced pulmonary hypertension.

CONCLUSIONS

Together, this study describes a novel proproliferative/prosurvival role of MST1/2 in PAH pulmonary vasculature, provides a novel mechanistic link from MST1/2 via BUB3 and forkhead homeobox type O to the abnormal proliferation and survival of pulmonary arterial vascular smooth muscle cells and pulmonary arterial adventitial fibroblasts, remodeling and pulmonary hypertension, and suggests new target pathways for therapeutic intervention.

Longevity Factor FOXO3: A Key Regulator in Aging-Related Vascular Diseases

Forkhead box O3 (FOXO3) has been proposed as a homeostasis regulator, capable of integrating multiple upstream signaling pathways that are sensitive to environmental changes and counteracting their adverse effects due to external changes, such as oxidative stress, metabolic stress and growth factor deprivation. FOXO3 polymorphisms are associated with extreme human longevity. Intriguingly, longevity-associated single nucleotide polymorphisms (SNPs) in human FOXO3 correlate with lower-than-average morbidity from cardiovascular diseases in long-lived people. Emerging evidence indicates that FOXO3 plays a critical role in vascular aging. FOXO3 inactivation is implicated in several aging-related vascular diseases. In experimental studies, FOXO3-engineered human ESC-derived vascular cells improve vascular homeostasis and delay vascular aging. The purpose of this review is to explore how FOXO3 regulates vascular aging and its crucial role in aging-related vascular diseases.

Integrative analysis of lung molecular signatures reveals key drivers of idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is a devastating disease with a high clinical burden. The molecular signatures of IPF were analyzed to distinguish molecular subgroups and identify key driver genes and therapeutic targets.

Methods

Thirteen datasets of lung tissue transcriptomics including 585 IPF patients and 362 normal controls were obtained from the databases and subjected to filtration of differentially expressed genes (DEGs). A functional enrichment analysis, agglomerative hierarchical clustering, network-based key driver analysis, and diffusion scoring were performed, and the association of enriched pathways and clinical parameters was evaluated.

Results

A total of 2,967 upregulated DEGs was filtered during the comparison of gene expression profiles of lung tissues between IPF patients and healthy controls. The core molecular network of IPF featured p53 signaling pathway and cellular senescence. IPF patients were classified into two molecular subgroups (C1, C2) via unsupervised clustering. C1 was more enriched in the p53 signaling pathway and ciliated cells and presented a worse prognostic score, while C2 was more enriched for cellular senescence, profibrosing pathways, and alveolar epithelial cells. The p53 signaling pathway was closely correlated with a decline in forced vital capacity and carbon monoxide diffusion capacity and with the activation of cellular senescence. CDK1/2, CKDNA1A, CSNK1A1, HDAC1/2, FN1, VCAM1, and ITGA4 were the key regulators as evidence by high diffusion scores in the disease module. Currently available and investigational drugs showed differential diffusion scores in terms of their target molecules.

Conclusions

An integrative molecular analysis of IPF lungs identified two molecular subgroups with distinct pathobiological characteristics and clinical prognostic scores. Inhibition against CDKs or HDACs showed great promise for controlling lung fibrosis. This approach provided molecular insights to support the prediction of clinical outcomes and the selection of therapeutic targets in IPF patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01749-3.

Control of Tissue Fibrosis by 5-Methoxytryptophan, an Innate Anti-Inflammatory Metabolite

Tissue fibrosis causes debilitating human diseases such as liver cirrhosis, heart failure, chronic kidney disease and pulmonary insufficiency. It is a dynamic process orchestrated by specific subsets of monocyte-macrophages, fibroblasts, pericytes and hepatic stellate cells. Fibrosis is linked to tissue inflammation. Pro-inflammatory macrophages promote fibrosis by driving myofibroblast differentiation and macrophage myofibroblast transition. Myofibroblasts express α-smooth muscle cell actin (α-SMA) and secrete extracellular matrix (ECM) proteins notably collagen I and III. Deposition of ECM proteins at injury sites and interstitial tissues distorts normal structure and impairs vital functions. Despite advances in the mechanisms of fibrosis at cellular, molecular and genetic levels, prevention and treatment of fibrotic diseases remain poorly developed. Recent reports suggest that 5-methoxytryptophan (5-MTP) is effective in attenuating injury-induced liver, kidney, cardiac and pulmonary fibrosis. It inhibits macrophage activation and blocks fibroblast differentiation to myofibroblasts. Furthermore, it inhibits hepatic stellate cell differentiation into myofibroblasts. As 5-MTP is an endogenous molecule derived from tryptophan catabolism via tryptophan hydroxylase pathway, it is well-suited as a lead compound for developing new anti-fibrotic drugs. This article provides an overview of 5-MTP synthesis, and a critical review of its anti-fibrotic activities. Its mechanisms of actions and potential therapeutic value will be discussed.

A single-cell transcriptomic landscape of the lungs of patients with COVID-19

The lung is the primary organ targeted by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), making respiratory failure a leading coronavirus disease 2019 (COVID-19)-related mortality. However, our cellular and molecular understanding of how SARS-CoV-2 infection drives lung pathology is limited. Here we constructed multi-omics and single-nucleus transcriptomic atlases of the lungs of patients with COVID-19, which integrate histological, transcriptomic and proteomic analyses. Our work reveals the molecular basis of pathological hallmarks associated with SARS-CoV-2 infection in different lung and infiltrating immune cell populations. We report molecular fingerprints of hyperinflammation, alveolar epithelial cell exhaustion, vascular changes and fibrosis, and identify parenchymal lung senescence as a molecular state of COVID-19 pathology. Moreover, our data suggest that FOXO3A suppression is a potential mechanism underlying the fibroblast-to-myofibroblast transition associated with COVID-19 pulmonary fibrosis. Our work depicts a comprehensive cellular and molecular atlas of the lungs of patients with COVID-19 and provides insights into SARS-CoV-2-related pulmonary injury, facilitating the identification of biomarkers and development of symptomatic treatments.

Genome-scale CRISPR-Cas9 knockout screening in hepatocellular carcinoma with lenvatinib resistance

Lenvatinib is the first target drug approved for advanced hepatocellular carcinoma (HCC). However, the development of drug resistance is common, and the mechanisms of lenvatinib resistance and resistant targets in HCC are poorly understood. By using CRISPR/Cas9 library screening, we screened out two key resistance genes, neurofibromin 1(NF1), and dual specificity phosphatase 9 (DUSP9), as critical drivers for lenvatinib resistance in HCC. With RNAi knockdown and CRISPR/Cas9 knockout models, we further clarified the mechanisms by which NF1 loss reactivates the PI3K/AKT and MAPK/ERK signaling pathways, while DUSP9 loss activates the MAPK/ERK signaling pathways, thereby inactivating FOXO3, followed by degradation of FOXO3, finally induced lenvatinib resistance. We also screened out trametinib, a small molecule pathway inhibitor for MEK, that can be used to reverse resistance induced by NF1 and DUSP9 loss in HCC cells. Trametinib was still able to halt HCC growth even when NF1 was knocked out in mice. Collectively, the findings indicate that NF1 and DUSP9 takes critical role in lenvatinib resistance and may be novel specific targets and predictive markers for lenvatinib resistance in HCC.

Up-regulation of miR-34b/c by JNK and FOXO3 protects from liver fibrosis

α1-Antitrypsin (AAT) deficiency is a common genetic disease presenting with lung and liver diseases. AAT deficiency results from pathogenic variants in the SERPINA1 gene encoding AAT and the common mutant Z allele of SERPINA1 encodes for Z α1-antitrypsin (ATZ), a protein forming hepatotoxic polymers retained in the endoplasmic reticulum of hepatocytes. PiZ mice express the human ATZ and are a valuable model to investigate the human liver disease of AAT deficiency. In this study, we investigated differential expression of microRNAs (miRNAs) between PiZ and control mice and found that miR-34b/c was up-regulated and its levels correlated with intrahepatic ATZ. Furthermore, in PiZ mouse livers, we found that Forkhead Box O3 (FOXO3) driving microRNA-34b/c (miR-34b/c) expression was activated and miR-34b/c expression was dependent upon c-Jun N-terminal kinase (JNK) phosphorylation on Ser⁵⁷⁴ Deletion of miR-34b/c in PiZ mice resulted in early development of liver fibrosis and increased signaling of platelet-derived growth factor (PDGF), a target of miR-34b/c. Activation of FOXO3 and increased miR-34c were confirmed in livers of humans with AAT deficiency. In addition, JNK-activated FOXO3 and miR-34b/c up-regulation were detected in several mouse models of liver fibrosis. This study reveals a pathway involved in liver fibrosis and potentially implicated in both genetic and acquired causes of hepatic fibrosis.

Integrative analysis of lung molecular signatures reveals key drivers of systemic sclerosis-associated interstitial lung disease

OBJECTIVES

Interstitial lung disease is a significant comorbidity and the leading cause of mortality in patients with systemic sclerosis. Transcriptomic data of systemic sclerosis-associated interstitial lung disease (SSc-ILD) were analysed to evaluate the salient molecular and cellular signatures in comparison with those in related pulmonary diseases and to identify the key driver genes and target molecules in the disease module.

METHODS

A transcriptomic dataset of lung tissues from patients with SSc-ILD (n=52), idiopathic pulmonary fibrosis (IPF) (n=549), non-specific interstitial pneumonia (n=49) and pulmonary arterial hypertension (n=81) and from normal healthy controls (n=331) was subjected to filtration of differentially expressed genes, functional enrichment analysis, network-based key driver analysis and kernel-based diffusion scoring. The association of enriched pathways with clinical parameters was evaluated in patients with SSc-ILD.

RESULTS

SSc-ILD shared key pathogenic pathways with other fibrosing pulmonary diseases but was distinguishable in some pathological processes. SSc-ILD showed general similarity with IPF in molecular and cellular signatures but stronger signals for myofibroblasts, which in SSc-ILD were in a senescent and apoptosis-resistant state. The p53 signalling pathway was the most enriched signature in lung tissues and lung fibroblasts of SSc-ILD, and was significantly correlated with carbon monoxide diffusing capacity of lung, cellular senescence and apoptosis. EEF2, EFF2K, PHKG2, VCAM1, PRKACB, ITGA4, CDK1, CDK2, FN1 and HDAC1 were key regulators with high diffusion scores in the disease module.

CONCLUSIONS

Integrative transcriptomic analysis of lung tissues revealed key signatures of fibrosis in SSc-ILD. A network-based Bayesian approach provides deep insights into key regulatory genes and molecular targets applicable to treating SSc-ILD.

Pharmaceutical targeting of succinate dehydrogenase in fibroblasts controls bleomycin-induced lung fibrosis

Idiopathic pulmonary fibrosis (IPF) is characterized by excessive deposition of extracellular matrix in the lung with fibroblast-to-myofibroblast transition, leading to chronically compromising lung function and death. However, very little is known about the metabolic alterations of fibroblasts in IPF, and there is still a lack of pharmaceutical agents to target the metabolic dysregulation. Here we show a glycolysis upregulation and fatty acid oxidation (FAO) downregulation in fibroblasts from fibrotic lung, and perturbation of glycolysis and FAO affects fibroblasts transdifferentiation. In addition, there is a significant accumulation of succinate both in fibrotic lung tissues and myofibroblasts, where succinate dehydrogenase (SDH) operates in reverse by reducing fumarate to succinate. Then succinate contributes to glycolysis upregulation and FAO downregulation by stabilizing HIF-1α, which promotes the development of lung fibrosis. In addition, we identify a near-infrared small molecule dye, IR-780, as a targeting agent which stimulates mild inhibition of succinate dehydrogenase subunit A (SDHA) in fibroblasts, and which inhibits TGF-β1 induced SDH and succinate elevation, then to prevent fibrosis formation and respiratory dysfunction. Further, enhanced cell retention of IR-780 is shown to promote severe inhibition of SDHA in myofibroblasts, which may contribute to excessive ROS generation and selectively induces myofibroblasts to apoptosis, and then therapeutically improves established lung fibrosis in vivo. These findings indicate that targeting metabolic dysregulation has significant implications for therapies aimed at lung fibrosis and succinate dehydrogenase is an exciting new therapeutic target to treat IPF.

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Glycolysis upregulation and fatty acid oxidation (FAO) downregulation in fibroblasts lead to lung fibrosis.

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Succinate contributes to metabolic dysregulation of fibroblasts by stabilizing HIF-1α.

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Succinate dehydrogenase is an exciting new therapeutic target to treat IPF.

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IR-780 can be a promising agent to control lung fibrosis by targeting succinate dehydrogenase.

Epigenetic Regulation by Suv4-20h1 in Cardiopulmonary Progenitor Cells is Required to Prevent Pulmonary Hypertension and COPD

Background: The etiology of life-threatening cardiopulmonary diseases such as Pulmonary Hypertension (PH) and Chronic Obstructive Pulmonary Disease (COPD) originates from a complex interplay of environmental factors and genetic predispositions, which is not fully understood. Likewise, little is known about developmental abnormalities or epigenetic dysregulations that might predispose for PH or COPD in adult individuals. Methods: To identify pathology-associated epigenetic alteration in diseased lung tissues, we screened a cohort of human PH and COPD patients for changes of histone modifications by immunofluorescence staining. To analyze the function of H4K20me2/3 in lung pathogenesis, we developed a series of Suv4-20h1 knockout mouse lines targeting cardiopulmonary progenitor cells (CPPs) and different heart and lung cell types, followed by hemodynamic studies and morphometric assessment of tissue samples. Molecular, cellular and biochemical techniques were applied to analyze the function of Suv4-20h1-dependent epigenetic processes in cardiopulmonary progenitor cells and their derivatives. Results: We discovered a strong reduction of the histone modifications H4K20me2/3 in human COPD but not PH patients, which depend on the activity of the H4K20 di-methyltransferase SUV4-20H1. Loss of Suv4-20h1 in CPPs caused a COPD-like/PH phenotype in mice including formation of perivascular tertiary lymphoid tissue and goblet cell hyperplasia, hyper-proliferation of smooth muscle cells/myofibroblasts, impaired alveolarization and maturation defects of the microvasculature leading to massive right ventricular dilatation and premature death. Mechanistically, SUV4-20H1 binds directly to the 5'-upstream regulatory element of superoxide dismutase 3 (Sod3) gene to repress its expression. Increased levels of the extracellular SOD3 enzyme in Suv4-20h1 mutants increases hydrogen peroxide (H2O2) concentrations, causing vascular defects and impairing alveolarization. Conclusions: Our findings reveal a pivotal role of the histone modifier SUV4-20H1 in cardiopulmonary co-development and uncover developmental origins of cardiopulmonary diseases. We assume that the study will facilitate the understanding of pathogenic events causing PH and COPD, and aid the development of epigenetic drugs for treatment of cardiopulmonary diseases.

Single-cell RNA-seq reveals lineage-specific regulatory changes of fibroblasts and vascular endothelial cells in keloids

Keloids are a benign dermal fibrotic disorder with features similar to malignant tumors. keloids remain a therapeutic challenge and lack medical therapies, which is partially due to the incomplete understanding of the pathogenesis mechanism. We performed single-cell RNA-seq of 28,064 cells from keloid skin tissue and adjacent relatively normal tissue. Unbiased clustering revealed substantial cellular heterogeneity of keloid tissue, which included 21 clusters assigned to 11 cell lineages. We observed significant expansion of fibroblast and vascular endothelial cell subpopulations in keloids, reflecting their strong association with keloid pathogenesis. Comparative analyses were performed to identify the dysregulated pathways, regulators and ligand-receptor interactions in keloid fibroblasts and vascular endothelial cells. Our results highlight the roles of transforming growth factor beta and Eph-ephrin signaling pathways in both the aberrant fibrogenesis and angiogenesis of keloids. Critical regulators probably involved in the fibrogenesis of keloid fibroblasts, such as TWIST1, FOXO3 and SMAD3, were identified. TWIST1 inhibitor harmine could significantly suppress the fibrogenesis of keloid fibroblasts. In addition, tumor-related pathways were activated in keloid fibroblasts and vascular endothelial cells, which may be responsible for the malignant features of keloids. Our study put insights into the pathogenesis of keloids and provides potential targets for medical therapies.

Potential for inhibition of checkpoint kinases 1/2 in pulmonary fibrosis and secondary pulmonary hypertension

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease characterised by exuberant tissue remodelling and associated with high unmet medical needs. Outcomes are even worse when IPF results in secondary pulmonary hypertension (PH). Importantly, exaggerated resistance to cell death, excessive proliferation and enhanced synthetic capacity are key endophenotypes of both fibroblasts and pulmonary artery smooth muscle cells, suggesting shared molecular pathways. Under persistent injury, sustained activation of the DNA damage response (DDR) is integral to the preservation of cells survival and their capacity to proliferate. Checkpoint kinases 1 and 2 (CHK1/2) are key components of the DDR. The objective of this study was to assess the role of CHK1/2 in the development and progression of IPF and IPF+PH.

METHODS AND RESULTS

Increased expression of DNA damage markers and CHK1/2 were observed in lungs, remodelled pulmonary arteries and isolated fibroblasts from IPF patients and animal models. Blockade of CHK1/2 expression or activity-induced DNA damage overload and reverted the apoptosis-resistant and fibroproliferative phenotype of disease cells. Moreover, inhibition of CHK1/2 was sufficient to interfere with transforming growth factor beta 1-mediated fibroblast activation. Importantly, pharmacological inhibition of CHK1/2 using LY2606368 attenuated fibrosis and pulmonary vascular remodelling leading to improvement in respiratory mechanics and haemodynamic parameters in two animal models mimicking IPF and IPF+PH.

CONCLUSION

This study identifies CHK1/2 as key regulators of lung fibrosis and provides a proof of principle for CHK1/2 inhibition as a potential novel therapeutic option for IPF and IPF+PH.

Exploring the therapeutic potential of forkhead box O for outfoxing COVID-19

The COVID-19 pandemic has wreaked unprecedented societal havoc worldwide. The infected individuals may present mild to severe symptoms, with nearly 20% of the confirmed patients impaired with significant complications, including multi-organ failure. Acute respiratory distress imposed by SARS-CoV-2 largely results from an aggravated cytokine storm and deregulated immune response. The forkhead box O (FoxO) transcription factors are reported to play a significant role in maintaining normal cell physiology by regulating survival, apoptosis, oxidative stress, development and maturation of T and B lymphocytes, secretion of inflammatory cytokines, etc. We propose a potent anti-inflammatory approach based on activation of the FoxO as an attractive strategy against the novel coronavirus. This regime will be focused on restoring redox and inflammatory homeostasis along with repair of the damaged tissue, activation of lymphocyte effector and memory cells. Repurposing FoxO activators as a means to alleviate the inflammatory burst following SARS-CoV-2 infection can prove immensely valuable in the ongoing pandemic and provide a reliable groundwork for enriching our repertoire of antiviral modalities for any such complication in the future. Altogether, our review highlights the possible efficacy of FoxO activation as a novel arsenal for clinical management of COVID-19.

Depletion of Numb and Numblike in Murine Lung Epithelial Cells Ameliorates Bleomycin-Induced Lung Fibrosis by Inhibiting the β-Catenin Signaling Pathway

Idiopathic pulmonary fibrosis (IPF) represents the most aggressive form of pulmonary fibrosis (PF) and is a highly debilitating disorder with a poorly understood etiology. The lung epithelium seems to play a critical role in the initiation and progression of the disease. A repeated injury of lung epithelial cells prompts type II alveolar cells to secrete pro-fibrotic cytokines, which induces differentiation of resident mesenchymal stem cells into myofibroblasts, thus promoting aberrant deposition of extracellular matrix (ECM) and formation of fibrotic lesions. Reactivation of developmental pathways such as the Wnt-β-catenin signaling cascade in lung epithelial cells plays a critical role in this process, but the underlying mechanisms are still enigmatic. Here, we demonstrate that the membrane-associated protein NUMB is required for pathological activation of β-catenin signaling in lung epithelial cells following bleomycin-induced injury. Importantly, depletion of Numb and Numblike reduces accumulation of fibrotic lesions, preserves lung functions, and increases survival rates after bleomycin treatment of mice. Mechanistically, we demonstrate that NUMB interacts with casein kinase 2 (CK2) and relies on CK2 to activate β-catenin signaling. We propose that pharmacological inhibition of NUMB signaling may represent an effective strategy for the development of novel therapeutic approaches against PF.

Spontaneous Lung Fibrosis Resolution Reveals Novel Antifibrotic Regulators

Fibroblast activation is transient in successful wound repair but persistent in fibrotic pathologies. Understanding fibroblast deactivation during successful wound healing may provide new approaches to therapeutically reverse fibroblast activation. To characterize the gene programs that accompany fibroblast activation and reversal during lung fibrosis resolution, we used RNA sequencing analysis of flow sorted Col1α1-GFP-positive and CD45-, CD31-, and CD326-negative cells isolated from the lungs of young mice exposed to bleomycin. We compared fibroblasts isolated from control mice with those isolated at Days 14 and 30 after bleomycin exposure, representing the peak of extracellular matrix deposition and an early stage of fibrosis resolution, respectively. Bleomycin exposure dramatically altered fibroblast gene programs at Day 14. Principal component and differential gene expression analyses demonstrated the predominant reversal of these trends at Day 30. Upstream regulator and pathway analyses of reversing "resolution" genes identified novel candidate antifibrotic genes and pathways. Two genes from these analyses that were decreased in expression at Day 14 and reversed at Day 30, Aldh2 and Nr3c1, were selected for further analysis. Enhancement of endogenous expression of either gene by CRISPR activation in cultured human idiopathic pulmonary fibrosis fibroblasts was sufficient to reduce profibrotic gene expression, fibronectin deposition, and collagen gel compaction, consistent with roles for these genes in fibroblast deactivation. This combination of RNA sequencing analysis of freshly sorted fibroblasts and hypothesis testing in cultured idiopathic pulmonary fibrosis fibroblasts offers a path toward identification of novel regulators of lung fibroblast deactivation, with potential relevance to understanding fibrosis resolution and its failure in human disease.

Pathogenesis of fibrosis in interstitial lung disease

PURPOSE OF REVIEW

Pulmonary fibrosis is a chronic and progressive lung disease involving unclear pathological mechanisms. The present review presents and discusses the major and recent advances in our knowledge of the pathogenesis of lung fibrosis.

RECENT FINDINGS

The past months have deepened our understanding on the cellular actors of fibrosis with a better characterization of the abnormal lung epithelial cells observed during lung fibrosis. Better insight has been gained into fibroblast biology and the role of immune cells during fibrosis. Mechanistically, senescence appears as a key driver of the fibrotic process. Extracellular vesicles have been discovered as participating in the impaired cellular cross-talk during fibrosis and deeper understanding has been made on developmental signaling in lung fibrosis.

SUMMARY

This review emphasizes the contribution of different cell types and mechanisms during pulmonary fibrosis, highlights new insights for identification of potential therapeutic strategies, and underlines where future research is needed to answer remaining open questions.

Constitutive immune activity promotes JNK- and FoxO-dependent remodeling of Drosophila airways

Extensive remodeling of the airways is a major characteristic of chronic inflammatory lung diseases such as asthma or chronic obstructive pulmonary disease (COPD). To elucidate the importance of a deregulated immune response in the airways for remodeling processes, we established a matching Drosophila model. Here, triggering the Imd (immune deficiency) pathway in tracheal cells induced organ-wide remodeling. This structural remodeling comprises disorganization of epithelial structures and comprehensive epithelial thickening. We show that these structural changes do not depend on the Imd pathway's canonical branch terminating on nuclear factor κB (NF-κB) activation. Instead, activation of a different segment of the Imd pathway that branches off downstream of Tak1 and comprises activation of c-Jun N-terminal kinase (JNK) and forkhead transcription factor of the O subgroup (FoxO) signaling is necessary and sufficient to mediate the observed structural changes of the airways. Our findings imply that targeting JNK and FoxO signaling in the airways could be a promising strategy to interfere with disease-associated airway remodeling processes.

Ginsenoside Rg3 inhibits pulmonary fibrosis by preventing HIF-1α nuclear localisation

Background

Excessive fibroblast proliferation during pulmonary fibrosis leads to structural abnormalities in lung tissue and causes hypoxia and cell injury. However, the mechanisms and effective treatment are still limited.

Methods

In vivo, we used bleomycin to induce pulmonary fibrosis in mice. IHC and Masson staining were used to evaluate the inhibitory effect of ginsenoside Rg3 in pulmonary fibrosis. In vitro, scanning electron microscopy, transwell and wound healing were used to evaluate the cell phenotype of LL 29 cells. In addition, biacore was used to detect the binding between ginsenoside Rg3 and HIF-1α.

Results

Here, we found that bleomycin induces the activation of the HIF-1α/TGFβ1 signalling pathway and further enhances the migration and proliferation of fibroblasts through the epithelial mesenchymal transition (EMT). In addition, molecular docking and biacore results indicated that ginsenoside Rg3 can bind HIF-1α. Therefore, Ginsenoside Rg3 can slow down the progression of pulmonary fibrosis by inhibiting the nuclear localisation of HIF-1α.

Conclusions

This finding suggests that early targeted treatment of hypoxia may have potential value in the treatment of pulmonary fibrosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01426-5.

Restoration of SIRT3 gene expression by airway delivery resolves age-associated persistent lung fibrosis in mice

Aging is a risk factor for progressive fibrotic disorders involving diverse organ systems, including the lung. Idiopathic pulmonary fibrosis, an age-associated degenerative lung disorder, is characterized by persistence of apoptosis-resistant myofibroblasts. In this report, we demonstrate that sirtuin-3 (SIRT3), a mitochondrial deacetylase, is downregulated in lungs of IPF human subjects and in mice subjected to lung injury. Over-expression of the SIRT3 cDNA via airway delivery restored capacity for fibrosis resolution in aged mice, in association with activation of the forkhead box transcription factor, FoxO3a, in fibroblasts, upregulation of pro-apoptotic members of the Bcl-2 family, and recovery of apoptosis susceptibility. While transforming growth factor-β1 reduced levels of SIRT3 and FoxO3a in lung fibroblasts, cell non-autonomous effects involving macrophage secreted products were necessary for SIRT3-mediated activation of FoxO3a. Together, these findings reveal a novel role of SIRT3 in pro-resolution macrophage functions that restore susceptibility to apoptosis in fibroblasts via a FoxO3a-dependent mechanism.

Transforming Growth Factor Beta-Induced Foxo3a Acts as a Profibrotic Mediator in Hepatic Stellate Cells

Hepatic stellate cells (HSCs) are major contributors to hepatic fibrogenesis facilitating liver fibrosis. Forkhead box O 3a (FoxO3a) is a member of the forkhead transcription factor family, which mediates cell proliferation and differentiation. However, the expression and function of FoxO3a during HSC activation remain largely unknown. FoxO3a overexpression was related to fibrosis in patients, and its expression was colocalized with desmin or α-smooth muscle actin, representative HSC markers. We also observed upregulated FoxO3a levels in two animal hepatic fibrosis models, a carbon tetrachloride-injected model and a bile duct ligation model. In addition, transforming growth factor beta (TGF-β) treatment in mouse primary HSCs or LX-2 cells elevated FoxO3a expression. When FoxO3a was upregulated by TGF-β in LX-2 cells, both the cytosolic and nuclear levels of FoxO3a increased. In addition, we found that the induction of FoxO3a by TGF-β was due to both transcriptional and proteasome-dependent mechanisms. Moreover, FoxO3a overexpression promoted TGF-β-mediated Smad activation. Furthermore, FoxO3a increased fibrogenic gene expression, which was reversed by FoxO3a knockdown. TGF-β-mediated FoxO3a overexpression in HSCs facilitated hepatic fibrogenesis, suggesting that FoxO3a may be a novel target for liver fibrosis prevention and treatment.