Kynurenine acts as a signaling molecule to attenuate pulmonary fibrosis by enhancing the AHR-PTEN axis.

INTRODUCTION: Pulmonary fibrosis (PF) is a fatal fibrotic lung disease without any options to halt disease progression. Feasible evidence suggests that aberrant metabolism of amino acids may play a role in the pathoetiology of PF. However, the exact impact of kynurenine (Kyn), a metabolite derived from tryptophan (Trp) on PF is yet to be addressed. OBJECTIVES: This study aims to elucidate the role of kynurenine in both the onset and advancement of PF. METHODS: Liquid chromatography-tandem mass spectrometry was employed to assess Kyn levels in patients with idiopathic PF and PF associated with Sjögren's syndrome. Additionally, a mouse model of PF induced by bleomycin was utilized to study the impact of Kyn administration. Furthermore, cell models treated with TGF-ß1 were used to explore the mechanism by which Kyn inhibits fibroblast functions. RESULTS: We demonstrated that high levels of Kyn are a clinical feature in both idiopathic PF patients and primary Sjögren syndrome associated PF patients. Further studies illustrated that Kyn served as a braking molecule to suppress fibroblast functionality, thereby protecting mice from bleomycin-induced lung fibrosis. The protective effects depend on AHR, in which Kyn induces AHR nuclear translocation, where it upregulates PTEN expression to blunt TGF-ß mediated AKT/mTOR signaling in fibroblasts. However, in fibrotic microenviroment, the expression of AHR is repressed by methyl-CpG-binding domain 2 (MBD2), a reader interpreting the effect of DNA methylation, which results in a significantly reduced sensitivity of Kyn to fibroblasts. Therefore, exogenous administration of Kyn substantially reversed established PF. CONCLUSION: Our studies not only highlighted a critical role of Trp metabolism in PF pathogenesis, but also provided compelling evidence suggesting that Kyn could serve as a promising metabolite against PF.

Critical COVID-19, Victivallaceae abundance, and celiac disease: A mediation Mendelian randomization study.

Celiac disease exhibits a higher prevalence among patients with coronavirus disease 2019. However, the potential influence of COVID-19 on celiac disease remains uncertain. Considering the significant association between gut microbiota alterations, COVID-19 and celiac disease, the two-step Mendelian randomization method was employed to investigate the genetic causality between COVID-19 and celiac disease, with gut microbiota as the potential mediators. We employed the genome-wide association study to select genetic instrumental variables associated with the exposure. Subsequently, these variables were utilized to evaluate the impact of COVID-19 on the risk of celiac disease and its potential influence on gut microbiota. Employing a two-step Mendelian randomization approach enabled the examination of potential causal relationships, encompassing: 1) the effects of COVID-19 infection, hospitalized COVID-19 and critical COVID-19 on the risk of celiac disease; 2) the influence of gut microbiota on celiac disease; and 3) the mediating impact of the gut microbiota between COVID-19 and the risk of celiac disease. Our findings revealed a significant association between critical COVID-19 and an elevated risk of celiac disease (inverse variance weighted [IVW]: P = 0.035). Furthermore, we observed an inverse correlation between critical COVID-19 and the abundance of Victivallaceae (IVW: P = 0.045). Notably, an increased Victivallaceae abundance exhibits a protective effect against the risk of celiac disease (IVW: P = 0.016). In conclusion, our analysis provides genetic evidence supporting the causal connection between critical COVID-19 and lower Victivallaceae abundance, thereby increasing the risk of celiac disease.

A comprehensive meta-analysis to identify susceptibility genetic variants for precocious puberty.

PURPOSE: Currently, several genetic variants in ERα gene (rs2234693 and rs9340799), ERß gene (rs1256049 and rs4986938), KISS1 gene (rs4889, rs1132506 and rs5780218), LIN28B gene (rs314263, rs314276 and rs314280), and MKRN3 gene (rs2239669) have been repeatedly explored for their contribution to precocious puberty (PP) susceptibility. However, the results remain conflicting rather than conclusive. We here performed a meta-analysis to identify the real susceptibility genetic variants for PP. METHODS: After screening by inclusion criteria, 20 related studies were finally included in this meta-analysis. The odds ratios and 95% confidence intervals were calculated to assess the strength of association. Sensitive analysis, publication bias, and trial sequential analysis (TSA) were performed to evaluate the stability and reliability of results. RESULTS: Rs2234693, rs9340799, and rs1256049 were significantly associated with PP susceptibility (p < 0.0084). Stratified analysis according to ethnicity showed that rs2234693 and rs9340799 were significantly associated with PP susceptibility in Asian and Chinese populations. Stratified analysis according to PP subtype showed that rs2234693 and rs9340799 were significantly associated with idiopathic central PP susceptibility in Asian and Chinese populations (p < 0.0084). The results of publication bias, sensitivity analysis, and TSA provided solid evidence for the association between these three variants and PP susceptibility. CONCLUSIONS: Rs2234693 and rs9340799 in ERα gene and rs1256049 in ERß gene may serve as susceptive factors for PP development. The present finding should be confirmed in replication studies and reinforced in functional studies, which will ultimately improve the feasibility of the application of these three PP-susceptible loci in clinical practice.

The efficacy of hydrogen/oxygen therapy favored the recovery of omicron SARS-CoV-2 variant infection: results of a multicenter, randomized, controlled trial.

Clinical studies had found that hydrogen/oxygen mixed inhalation was beneficial to ameliorate the respiratory symptoms in the adjuvant treatment of patients with COVID-19. We aimed to explore the efficacy of hydrogen/oxygen therapy in favoring the recovery of Omicron SARS-CoV-2 variant infection. There were 64 patients who randomly assigned to receive hydrogen/oxygen inhalation (32 patients) and oxygen inhalation (32 patients). The average shedding duration of Omicron in hydrogen/oxygen group was shorter than oxygen group. The trend of cumulative negative conversion rate of Omicron increased gradually after the third day. The IL-6 levels in hydrogen/oxygen group decreased by 22.8% compared with the baseline. After hydrogen/oxygen mixed gas inhalation, the lymphocyte count increased to 61.1% of the baseline on the 3rd day in the hydrogen/oxygen group. More patients in the hydrogen/oxygen group had resolution of pulmonary lesions. Our study showed the beneficial trends of molecular hydrogen in treating patients with COVID-19, which may offer a prospective solution to adjuvant therapy for COVID-19 Patients.

Nuclear receptor corepressor 1 deficiency exacerbates asthma by modulating macrophage polarization.

Macrophage polarization plays an important role in asthma. Nuclear receptor corepressor 1 (NCOR1) plays an important role in metabolic and cardiovascular diseases by regulating the function of macrophages. The aim of this research was to examine the role and mechanism of macrophage NCOR1 in the development of asthma. We used ovalbumin (OVA) to induce macrophage NCOR1-deficient mice for asthma formation. Our results revealed that macrophage NCOR1 deficiency markedly enhanced allergic airway inflammation. In addition, NCOR1 deficiency in macrophages was found to enhance M2 polarization. Mechanistic studies suggested that NCOR1 promoted macrophage polarization by interacting with PPARγ, contributing to the pathogenesis of asthma. In conclusion, macrophage NCOR1 deficiency promoted the regulation of M2 programming by enhancing PPARγ expression to exacerbate asthma. Macrophage NCOR1 might be a potential target for the treatment of asthma.

Local administration of liposomal-based Plekhf1 gene therapy attenuates pulmonary fibrosis by modulating macrophage polarization.

Idiopathic pulmonary fibrosis (IPF) is a fatal interstitial lung disease with limited therapeutic options. Macrophages, particularly alternatively activated macrophages (M2), have been recognized to contribute to the pathogenesis of pulmonary fibrosis. Therefore, targeting macrophages might be a viable therapeutic strategy for IPF. Herein, we report a potential nanomedicine-based gene therapy for IPF by modulating macrophage M2 activation. In this study, we illustrated that the levels of pleckstrin homology and FYVE domain containing 1 (Plekhf1) were increased in the lungs originating from IPF patients and PF mice. Further functionality studies identified the pivotal role of Plekhf1 in macrophage M2 activation. Mechanistically, Plekhf1 was upregulated by IL-4/IL-13 stimulation, after which Plekhf1 enhanced PI3K/Akt signaling to promote the macrophage M2 program and exacerbate pulmonary fibrosis. Therefore, intratracheal administration of Plekhf1 siRNA-loaded liposomes could effectively suppress the expression of Plekhf1 in the lungs and notably protect mice against BLM-induced lung injury and fibrosis, concomitant with a significant reduction in M2 macrophage accumulation in the lungs. In conclusion, Plekhf1 may play a crucial role in the pathogenesis of pulmonary fibrosis, and Plekhf1 siRNA-loaded liposomes might be a promising therapeutic approach against pulmonary fibrosis.

MBD2 facilitates tumor metastasis by mitigating DDB2 expression.

Despite past extensive studies, the pathoetiologies underlying tumor metastasis remain poorly understood, which renders its treatment largely unsuccessful. The methyl-CpG-binding domain 2 (MBD2), a "reader" to interpret DNA methylome-encoded information, has been noted to be involved in the development of certain types of tumors, while its exact impact on tumor metastasis remains elusive. Herein we demonstrated that patients with LUAD metastasis were highly correlated with enhanced MBD2 expression. Therefore, knockdown of MBD2 significantly attenuated the migration and invasion of LUAD cells (A549 and H1975 cell lines) coupled with attenuated epithelial-mesenchymal transition (EMT). Moreover, similar results were observed in other types of tumor cells (B16F10). Mechanistically, MBD2 selectively bound to the methylated CpG DNA within the DDB2 promoter, by which MBD2 repressed DDB2 expression to promote tumor metastasis. As a result, administration of MBD2 siRNA-loaded liposomes remarkably suppressed EMT along with attenuated tumor metastasis in the B16F10 tumor-bearing mice. Collectively, our study indicates that MBD2 could be a promising prognostic marker for tumor metastasis, while administration of MBD2 siRNA-loaded liposomes could be a viable therapeutic approach against tumor metastasis in clinical settings.

The rs41291957 polymorphism of miR-143/145 and cancer risk: a case-control study and meta-analysis.

Recently, the rs41291957 polymorphism in the promoter region of miR-143/145 has been repeatedly investigated for its contribution to cancer susceptibility. However, the results remain conflicting rather than conclusive, which calls for further investigations. Therefore, we here conducted a case-control study and meta-analysis to explore the association between rs41291957 and cancer risk. In the case-control study, a total of 2277 cancer patients (lung, liver, gastric and colorectal cancers) and 800 normal controls were recruited, the genotyping of rs41291957 was performed with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and Sanger sequencing. In the meta-analysis, 5 previously published studies and our present study were included, the STATA 14.0 software was applied to conduct all statistical analyses. The results of case-control study showed that rs41291957 was significantly associated with the risk of gastric cancer, colon cancer, rectal cancer, and colorectal cancer in Hubei Han Chinese population. The results of meta-analysis demonstrated that rs41291957 was significantly associated with overall cancer risk, especially colorectal cancer risk and lung cancer risk. Collectively, the rs41291957 polymorphism of miR-143/145 may be a plausible susceptible locus for cancer risk, which should be validated in future studies with larger samples in different ethnic populations.

The contribution of MALAT1 gene rs3200401 and MEG3 gene rs7158663 to the risk of lung, colorectal, gastric and liver cancer.

Previous studies have repeatedly investigated the effects of MALAT1 gene rs3200401 and MEG3 gene rs7158663 on cancer risk. However, their results remain conflicting rather than conclusive. Therefore, we here performed a case-control study and a followed meta-analysis to examine their contribution to the risk of lung, colorectal, gastric and liver cancer. 550 lung cancer patients, 787 colorectal cancer patients, 460 gastric cancer patients, 480 liver cancer patients and 800 normal controls were included. The genotyping of rs3200401 and rs7158663 was applied with Sanger sequencing technology. Our case-control study revealed that in Hubei Chinese population, rs3200401 was significantly associated with the risk of gastric cancer but not lung, colorectal, or liver cancer, rs7158663 was significantly associated with the risk of gastric and colorectal cancer but not lung or liver cancer. The followed meta-analysis, combining the data of previous studies and present study, showed that rs3200401 was significantly associated with the risk of gastric and colorectal cancer in the pooled population but not liver cancer in Chinese population, rs7158663 was significantly associated with the risk of lung, colorectal and gastric but not liver cancer in Chinese population. Collectively, MALAT1 gene rs3200401 may be a susceptive factor for the development of colorectal and gastric cancer, and MEG3 gene rs7158663 may be a susceptive factor for the development of lung, colorectal and gastric cancer. However, the findings should be validated in future studies with larger sample sizes of different ethnic populations.

Blockade of Mbd2 by siRNA-loaded liposomes protects mice against OVA-induced allergic airway inflammation via repressing M2 macrophage production.

Objective: To address the role of methyl-CpG-binding domain 2 (MBD2) in the pathogenesis of asthma and its potential as a target for the asthmatic therapy. Methods: Studies were conducted in asthmatic patients and macrophage-specific Mbd2 knockout mice to dissect the role of MBD2 in asthma pathogenesis. Additionally, RNAi-based therapy with Mbd2 siRNA-loaded liposomes was conducted in an ovalbumin (OVA)-induced allergic airway inflammation mouse model. Results: Asthmatic patients and mice challenged with OVA exhibited upregulated MBD2 expression in macrophages, especially in alternatively activated (M2) macrophages. In particular, macrophage-specific knockout of Mbd2 protected mice from OVA-induced allergic airway inflammation and suppressed the M2 program. Notably, intratracheal administration of liposomes carrying Mbd2 siRNA decreased the expression of Mbd2 and prevented OVA-induced allergic airway inflammation in mice, as indicated by the attenuated airway inflammation and mucus production. Conclusions: The above data indicate that Mbd2 implicates in the pathogenesis of asthma predominantly by regulating the polarization of M2 macrophages, which supports that Mbd2 could be a viable target for treatment of asthma in clinical settings.

Erratum: Local administration of liposomal-based Srpx2 gene therapy reverses pulmonary fibrosis by blockading fibroblast-to-myofibroblast transition: Erratum.

[This corrects the article DOI: 10.7150/thno.61085.].

Macrophage-targeted delivery of siRNA to silence Mecp2 gene expression attenuates pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease characterized by the infiltration of macrophages in the fibrotic region. Currently, no therapeutic strategies effectively control disease progression, and the 5-year mortality of patients after diagnosis is unacceptably high. Thus, developing an effective and safe treatment for IPF is urgently needed. The present study illustrated that methyl-CpG-binding protein 2 (MECP2), a protein responsible for the interpretation of DNA methylome-encoded information, was abnormally expressed in lung and bronchoalveolar lavage fluid samples of IPF patients and mice with onset of pulmonary fibrosis. And further studies verified that the overexpression of MECP2 occurred mainly in macrophages. Inhibition of Mecp2 expression in macrophages robustly abrogated alternatively activated macrophage (M2) polarization by regulating interferon regulatory factor 4 expression. Accordingly, cationic liposomes loading Mecp2 small interfering RNA (siRNA) were raised for the treatment of pulmonary fibrosis. It was noted that the liposomes accumulated in the fibrotic region after intratracheal injection, especially in macrophages. In addition, intratracheal administration of Mecp2 siRNA-loaded liposomes significantly reversed the established pulmonary fibrosis with few side-effects and high safety coefficients. Collectively, these results are essential not only for further understanding the DNA methylation in pathogenesis of IPF but also for providing a potent therapeutic strategy for IPF treatment in the clinic practice.

Multi-omics analysis unravels dysregulated lysosomal function and lipid metabolism involved in sub-chronic particulate matter-induced pulmonary injury.

Particulate matter (PM) is a huge environmental threat and is of major public concern. Oxidative stress and systemic inflammation are known factors that contribute to PM- related damage; however, a systematic understanding of the deleterious pulmonary effects of PM using multi-omics analysis is lacking. In this study, we performed transcriptomic, proteomic, and metabolomic analyses in a mouse model exposed to PM for three months to identify molecular changes in lung tissues. We identified 1690 genes, 326 proteins, and 67 metabolites exhibiting significant differences between PM-challenged and control mice (p < 0.05). Differentially expressed genes and proteins regulated in PM-challenged mice were involved in lipid metabolism and in the immune and inflammatory response processes. Moreover, a comprehensive analysis of transcript, protein, and metabolite datasets revealed that the genes, proteins, and metabolites in the PM-treated group were involved in lysosomal function and lipid metabolism. Specifically, Cathepsin D (Ctsd), Ferritin light chain (Ftl), Lactotransferrin (Ltf), Lipocalin 2 (Lcn2), and Prosaposin (Psap) were major proteins/genes associated with PM-induced pulmonary damage, while two lipid molecules PC (18:1(11Z)/16:0) and PA (16:0/18:1(11Z)) were major metabolites related to PM-induced pulmonary injury. In summary, lipid metabolism might be used as successful precautions and therapeutic targets in PM-induced pulmonary injury to maintain the stability of cellular lysosomal function.

Tartrate-resistant acid phosphatase 5 promotes pulmonary fibrosis by modulating ß-catenin signaling.

Idiopathic pulmonary fibrosis (IPF) is a fatal interstitial lung disease with limited therapeutic options. Tartrate-resistant acid phosphatase 5 (ACP5) performs a variety of functions. However, its role in IPF remains unclear. Here, we demonstrate that the levels of ACP5 are increased in IPF patient samples and mice with bleomycin (BLM)-induced pulmonary fibrosis. In particular, higher levels of ACP5 are present in the sera of IPF patients with a diffusing capacity of the lungs for carbonmonoxide (DLCO) less than 40% of the predicted value. Additionally, Acp5 deficiency protects mice from BLM-induced lung injury and fibrosis coupled with a significant reduction of fibroblast differentiation and proliferation. Mechanistic studies reveal that Acp5 is upregulated by transforming growth factor-ß1 (TGF-ß1) in a TGF-ß receptor 1 (TGFßR1)/Smad family member 3 (Smad3)-dependent manner, after which Acp5 dephosphorylates p-ß-catenin at serine 33 and threonine 41, inhibiting the degradation of ß-catenin and subsequently enhancing ß-catenin signaling in the nucleus, which promotes the differentiation, proliferation and migration of fibroblast. More importantly, the treatment of mice with Acp5 siRNA-loaded liposomes or Acp5 inhibitor reverses established lung fibrosis. In conclusions, Acp5 is involved in the initiation and progression of pulmonary fibrosis and strategies aimed at silencing or suppressing Acp5 could be considered as potential therapeutic approaches against pulmonary fibrosis.

The methyl-CpG-binding domain 2 facilitates pulmonary fibrosis by orchestrating fibroblast to myofibroblast differentiation.

Although DNA methylation has been recognised in the pathogenesis of idiopathic pulmonary fibrosis (IPF), the exact mechanisms are yet to be fully addressed. Herein, we demonstrate that lungs originated from IPF patients and mice after bleomycin (BLM)-induced pulmonary fibrosis are characterised by altered DNA methylation along with overexpression in myofibroblasts of methyl-CpG-binding domain 2 (MBD2), a reader responsible for interpreting DNA methylome-encoded information. Specifically, depletion of Mbd2 in fibroblasts or myofibroblasts protected mice from BLM-induced pulmonary fibrosis coupled with a significant reduction of fibroblast differentiation. Mechanistically, transforming growth factor (TGF)-ß1 induced a positive feedback regulatory loop between TGF-ß receptor I (TßRI), Smad3 and Mbd2, and erythroid differentiation regulator 1 (Erdr1). TGF-ß1 induced fibroblasts to undergo a global DNA hypermethylation along with Mbd2 overexpression in a TßRI/Smad3 dependent manner, and Mbd2 selectively bound to the methylated CpG DNA within the Erdr1 promoter to repress its expression, through which it enhanced TGF-ß/Smad signalling to promote differentiation of fibroblast into myofibroblast and exacerbate pulmonary fibrosis. Therefore, enhancing Erdr1 expression strikingly reversed established pulmonary fibrosis. Collectively, our data support that strategies aimed at silencing Mbd2 or increasing Erdr1 could be viable therapeutic approaches for prevention and treatment of pulmonary fibrosis in clinical settings.

Stem cell therapy for chronic obstructive pulmonary disease.

ABSTRACT: Chronic obstructive pulmonary disease (COPD), characterized by persistent and not fully reversible airflow restrictions, is currently one of the most widespread chronic lung diseases in the world. The most common symptoms of COPD are cough, expectoration, and exertional dyspnea. Although various strategies have been developed during the last few decades, current medical treatment for COPD only focuses on the relief of symptoms, and the reversal of lung function deterioration and improvement in patient's quality of life are very limited. Consequently, development of novel effective therapeutic strategies for COPD is urgently needed. Stem cells were known to differentiate into a variety of cell types and used to regenerate lung parenchyma and airway structures. Stem cell therapy is a promising therapeutic strategy that has the potential to restore the lung function and improve the quality of life in patients with COPD. This review summarizes the current state of knowledge regarding the clinical research on the treatment of COPD with mesenchymal stem cells (MSCs) and aims to update the understanding of the role of MSCs in COPD treatment, which may be helpful for developing effective therapeutic strategies in clinical settings.

Local administration of liposomal-based Srpx2 gene therapy reverses pulmonary fibrosis by blockading fibroblast-to-myofibroblast transition.

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive fatal interstitial lung disease characterized by abnormal transition and proliferation of fibroblasts. The uncontrolled transition of fibroblasts, commonly known as myofibroblasts, are the principal source of the enormous extracellular matrix (ECM) depositing in lung parenchyma, leading to gradual failure of gas exchange and mortality of the patients. However, up to now, rare effective therapeutic strategies have been developed to blockade fibroblast-to-myofibroblast transition (FMT) in IPF. Method: We illustrated that the lungs originated from IPF patients and mice with pulmonary fibrosis are characterized by the overexpression of sushi-repeat-containing protein, X-linked 2 (SRPX2). Further functionality studies identified the pivotal role of SRPX2 in FMT. Mechanistically, SRPX2 was involved in a TGFßR1/SMAD3/SRPX2/AP1/SMAD7 positive feedback loop. Specifically, SRPX2 was upregulated by TGF-ß1 in a TGFßR1/SMAD3-dependent manner, after which SRPX2 in turn repressed the expression of AP1, subsequently minimized SMAD7 expression, through which it reduced the formation of inhibitory complex with TGFßR1 and enhanced SMAD signaling pathway to promote FMT and exacerbate pulmonary fibrosis. Notably, intratracheal administration of siRNA-loaded liposomes could effectively suppress the expression of Srpx2 in the lung and remarkably protect mice against BLM-induced pulmonary fibrosis, concomitant with a significant reduction of FMT. Results: Accordingly, these data indicate that Srpx2 plays an essential role in the pathogenesis of pulmonary fibrosis and suggests the strategy aiming at silencing Srpx2 could be a promising therapeutic approach against pulmonary fibrosis in clinical settings.

Targeted resequencing showing novel common and rare genetic variants increases the risk of asthma in the Chinese Han population.

BACKGROUND: Although studies have identified hundreds of genetic variants associated with asthma risk, a large fraction of heritability remains unexplained, especially in Chinese individuals. METHODS: To identify genetic risk factors for asthma in a Han Chinese population, 211 asthma-related genes were first selected based on database searches. The genes were then sequenced for subjects in a Discovery Cohort (284 asthma patients and 205 older healthy controls) using targeted next-generation sequencing. Bioinformatics analysis and statistical association analyses were performed to reveal the associations between rare/common variants and asthma, respectively. The identified common risk variants underwent a validation analysis using a Replication Cohort (664 patients and 650 controls). RESULTS: First, we identified 18 potentially functional rare loss-of-function (LOF) variants in 21/284 (7.4%) of the asthma cases. Second, using burden tests, we found that the asthma group had nominally significant (p < 0.05) burdens of rare nonsynonymous variants in 10 genes. Third, 23 common single-nucleotide polymorphisms were associated with the risk of asthma, 7/23 (30.4%) and 9/23 (39.1%) of which were modestly significant (p < 9.1 × 10-4 ) in the Replication Cohort and Combined Cohort, respectively. According to our cumulative risk model involving the modestly associated alleles, middle- and high-risk subjects had a 2.0-fold (95% CI: 1.621-2.423, p = 2.624 × 10-11 ) and 6.0-fold (95% CI: 3.623-10.156, p = 7.086 × 10-12 ) increased risk of asthma, respectively, compared with low-risk subjects. CONCLUSION: This study revealed novel rare and common genetic risk factors for asthma, and provided a cumulative risk model for asthma risk prediction and stratification in Han Chinese individuals.