Suppression of NADPH oxidase 4 inhibits PM2.5-induced cardiac fibrosis through ROS-P38 MAPK pathway

The mechanisms underlying the cardiac effects of modified citrus pectin in obese rats with myocardial ischemia: Role of galectin-3

BACKGROUND

Modified citrus pectin (MCP) is used as a nutritional supplement that inhibits galectin-3 activity, a central player in the cardiac damage associated with different pathological situations. In fact, we have previously observed that MCP improved cardiac function in obese infarcted rats that was associated with a reduction in cardiac fibrosis. Therefore, the aim of the present study was to further explore whether this effect could involve the modulation of gene expression of ECM components and their mediators as well as whether it could affect another two mechanisms involved in cardiac damage: mitochondrial dynamics and autophagic flux.

METHODS

Male Wistar rats were fed an atherogenic diet with a high content of saturated fat (35%). MI was induced by the ligation of left anterior descendant (LAD) coronary artery 6 weeks after and MCP (100mg/kg/day) or vehicle were administered for 4 weeks more. A group of rats fed a standard diet (5.3% fat) and subjected to a sham operation was used as controls.

RESULTS

Obese infarcted animals presented an increase in cross-linked collagen that was not affected by the administration of galectin-3 inhibitor. However, MCP reduced the increase in gene expression observed in obese infarcted rats of ECM components and mediators (collagen I, fibronectin, transforming growth factor-β and connective tissue growth factor), of components of endoplasmic reticulum stress (binding immunoglobulin protein, CCAAT-enhancer-binding homologous protein and activating transcription factor 4), of oxidative stress mediator (NADPH oxidase-4) and normalized those of the interleukin 33/ST2 system. MCP is also able to increase the levels of the mitochondrial protein Dynamin-1-like and those of both proteins involved in autophagic flux (p62 and LC3) that were reduced by the myocardial ischemia in the context of obesity.

CONCLUSIONS

The data show that the beneficial effect of the nutritional supplement MCP on the cardiac consequences associated with myocardial ischemia in the context of obesity could rely on its capacity to inhibit galectin-3 and to consequently modulate different downstream mechanisms, including inflammation, ER stress, oxidative stress, autophagy and mitochondrial function, which can facilitate fibrosis and cardiac remodeling in this pathological context.

Insight into the cardioprotective effects of melatonin: shining a spotlight on intercellular Sirt signaling communication

Cardiovascular diseases (CVDs) are the leading causes of death and illness worldwide. While there have been advancements in the treatment of CVDs using medication and medical procedures, these conventional methods have limited effectiveness in halting the progression of heart diseases to complete heart failure. However, in recent years, the hormone melatonin has shown promise as a protective agent for the heart. Melatonin, which is secreted by the pineal gland and regulates our sleep-wake cycle, plays a role in various biological processes including oxidative stress, mitochondrial function, and cell death. The Sirtuin (Sirt) family of proteins has gained attention for their involvement in many cellular functions related to heart health. It has been well established that melatonin activates the Sirt signaling pathways, leading to several beneficial effects on the heart. These include preserving mitochondrial function, reducing oxidative stress, decreasing inflammation, preventing cell death, and regulating autophagy in cardiac cells. Therefore, melatonin could play crucial roles in ameliorating various cardiovascular pathologies, such as sepsis, drug toxicity-induced myocardial injury, myocardial ischemia-reperfusion injury, hypertension, heart failure, and diabetic cardiomyopathy. These effects may be partly attributed to the modulation of different Sirt family members by melatonin. This review summarizes the existing body of literature highlighting the cardioprotective effects of melatonin, specifically the ones including modulation of Sirt signaling pathways. Also, we discuss the potential use of melatonin-Sirt interactions as a forthcoming therapeutic target for managing and preventing CVDs.

Therapeutic application of nicotinamide: As a potential target for inhibiting fibrotic scar formation following spinal cord injury

AIM

We aimed to confirm the inhibitory effect of nicotinamide on fibrotic scar formation following spinal cord injury in mice using functional metabolomics.

METHODS

We proposed a novel functional metabolomics strategy to establish correlations between gene expression changes and metabolic phenotypes using integrated multi-omics analysis. Through the integration of quantitative metabolites analysis and assessments of differential gene expression, we identified nicotinamide as a functional metabolite capable of inhibiting fibrotic scar formation and confirmed the effect in vivo using a mouse model of spinal cord injury. Furthermore, to mimic fibrosis models in vitro, primary mouse embryonic fibroblasts and spinal cord fibroblasts were stimulated by TGFβ, and the influence of nicotinamide on TGFβ-induced fibrosis-associated genes and its underlying mechanism were examined.

RESULTS

Administration of nicotinamide led to a reduction in fibrotic lesion area and promoted functional rehabilitation following spinal cord injury. Nicotinamide effectively downregulated the expression of fibrosis genes, including Col1α1, Vimentin, Col4α1, Col1α2, Fn1, and Acta2, by repressing the TGFβ/SMADs pathway.

CONCLUSION

Our functional metabolomics strategy identified nicotinamide as a metabolite with the potential to inhibit fibrotic scar formation following SCI by suppressing the TGFβ/SMADs signaling. This finding provides new therapeutic strategies and new ideas for clinical treatment.

The effects of fine particulate matter on the blood-testis barrier and its potential mechanisms

With the rapid expansion of industrial scale, an increasing number of fine particulate matter (PM2.5) has bringing health concerns. Although exposure to PM2.5 has been clearly associated with male reproductive toxicity, the exact mechanisms are still unclear. Recent studies demonstrated that exposure to PM2.5 can disturb spermatogenesis through destroying the blood-testis barrier (BTB), consisting of different junction types, containing tight junctions (TJs), gap junctions (GJs), ectoplasmic specialization (ES) and desmosomes. The BTB is one of the tightest blood-tissue barriers among mammals, which isolating germ cells from hazardous substances and immune cell infiltration during spermatogenesis. Therefore, once the BTB is destroyed, hazardous substances and immune cells will enter seminiferous tubule and cause adversely reproductive effects. In addition, PM2.5 also has shown to cause cells and tissues injury via inducing autophagy, inflammation, sex hormones disorder, and oxidative stress. However, the exact mechanisms of the disruption of the BTB, induced by PM2.5, are still unclear. It is suggested that more research is required to identify the potential mechanisms. In this review, we aim to understand the adverse effects on the BTB after exposure to PM2.5 and explore its potential mechanisms, which provides novel insight into accounting for PM2.5-induced BTB injury.

Expression Profiles and Bioinformatic Analysis of Circular RNAs in Db/Db Mice with Cardiac Fibrosis

Introduction

Cardiac fibrosis is one of the important causes of heart failure and death in diabetic cardiomyopathy (DCM) patients. Circular RNAs (circRNAs) are covalently closed RNA molecules in eukaryotes and have high stability. Their role in myocardial fibrosis with diabetic cardiomyopathy (DCM) remain to be fully elucidated. This study aimed to understand the expression profiles of circRNAs in myocardial fibrosis with DCM, exploring the possible biomarkers and therapeutic targets for DCM.

Methods

At 21 weeks of age, db/db mice established the type 2 DCM model measured by echocardiography, and the cardiac tissue was extracted for Hematoxylin-eosin, Masson's trichrome staining, and transmission electron microscopy. Subsequently, the expression profile of circRNAs in myocardial fibrosis of db/db mice was constructed using microarray hybridization and verified by real-time quantitative polymerase chain reaction. A circRNA-microRNA-messenger RNA coexpression network was constructed, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis were done.

Results

Compared with normal control mice, db/db mice had 77 upregulated circRNAs and 135 downregulated circRNAs in their chromosomes (fold change ≥1.5, P ≤ 0.05). Moreover, the enrichment analysis of circRNA host genes showed that these differentially expressed circRNAs were mainly involved in mitogen-activated protein kinase signaling pathways. CircPHF20L1, circCLASP1, and circSLC8A1 were the key circRNAs. Moreover, circCLASP1/miR-182-5p/Wnt7a, circSLC8A1/miR-29b-1-5p/Col12a1, and most especially circPHF20L1/miR-29a-3p/Col6a2 might be three novel axes in the development of myocardial fibrosis in DCM.

Conclusion

The findings will provide some novel circRNAs and molecular pathways for the prevention or clinical treatment of DCM through intervention with specific circRNAs.

[Quercetin Alleviates H2O2-Induced Oxidative Stress Damage to Human Endometrial Stromal Cells by Inhibiting the p38 MAPK/NOX4 Signaling Pathway]

Objective

This study aims to systematically evaluate the protective role of quercetin (QCT), a naturally occurring flavonoid, against oxidative damage in human endometrial stromal cells (HESCs) induced by hydrogen peroxide (H2O2). Oxidative stress, such as that induced by H2O2, is known to contribute significantly to cellular damage and has been implicated in various reproductive health issues. The study is focused on investigating how QCT interacts with specific molecular pathways to mitigate this damage. Special attention was given to the p38 MAPK/NOX4 signaling pathway, which is crucial to the regulation of oxidative stress responses in cellular systems. By elucidating these mechanisms, the study seeks to confirm the potential of QCT not only as a protective agent against oxidative stress but also as a therapeutic agent that could be integrated in treatments of conditions characterized by heightened oxidative stress in endometrial cells.

Methods

I n vitro cultures of HESCs were treated with QCT at different concentrations (0, 10, 20, and 40 μmol/L) for 24 h to verify the non-toxic effects of QCT on normal endometrial cells. Subsequently, 250 μmol/L H2O2 was used to incubate the cells for 12 h to establish an H2O2-induced HESCs injury model. HESCs were pretreated with QCT for 24 h, which was followed by stimulation with H2O2. Then, CCK-8 assay was performed to examine the cell viability and to screen for the effective intervention concentration. HESCs were divided into 3 groups, the control group, the H2O2 model group, and the H2O2+QCT group. Intracellular levels of reactive oxygen species (ROS) were precisely quantified using the DCFH-DA fluorescence assay, a method known for its accuracy in detecting and quantifying oxidative changes within the cell. The mitochondrial membrane potential was determined by JC-1 staining. Annexin Ⅴ/PI double staining and flow cytometry were performed to determine the effect of QCT on H2O2-induced apoptosis of HESCs. Furthermore, to delve deeper into the cellular mechanisms underlying the observed effects, Western blot analysis was conducted to measure the expression levels of the critical proteins involved in oxidative stress response, including NADPH oxidase 4 (NOX4), p38 mitogen-activated protein kinase (p38 MAPK), and phosphorylated p38 MAPK (p-p38 MAPK). This analysis helps increase understanding of the specific intracellular signaling pathways affected by QCT treatment, giving special attention to its potential for modulation of the p38 MAPK/NOX4 pathway, which plays a significant role in cellular defense mechanisms against oxidative stress.

Results

In this study, we started off by assessing the toxicity of QCT on normal endometrial cells. Our findings revealed that QCT at various concentrations (0, 10, 20, and 40 μmol/L) did not exhibit any cytotoxic effects, which laid the foundation for further investigation into its protective roles. In the H2O2-induced HESCs injury model, a significant reduction in cell viability was observed, which was linked to the generation of ROS and the resultant oxidative damage. However, pretreatment with QCT (10 μmol/L and 20 μmol/L) significantly enhanced cell viability after 24 h (P<0.05), with the 20 μmol/L concentration showing the most substantial effect. This suggests that QCT can effectively reverse the cellular damage caused by H2O2. Furthermore, the apoptosis assays demonstrated a significant increase in the apoptosis rates in the H2O2 model group compared to those in the control group (P<0.01). However, co-treatment with QCT significantly reversed this trend (P<0.05), indicating QCT's potential protective role in mitigating cell apoptosis. ROS assays showed that, compared to that in the control group, the average fluorescence intensity of ROS in the H2O2 model group significantly increased (P<0.01). QCT treatment significantly reduced the ROS fluorescence intensity in the H2O2+QCT group compared to the that in the H2O2 model group, suggesting an effective alleviation of oxidative damage (P<0.05). JC-1 staining for mitochondrial membrane potential changes revealed that compared to that in the control, the proportion of cells with decreased mitochondrial membrane potential significantly increased in the H2O2 model group (P<0.01). However, this proportion was significantly reduced in the QCT-treated group compared to that of the H2O2 model group (P<0.05). Finally, Western blot analysis indicated that the expression levels of NOX4 and p-p38 MAPK proteins were elevated in the H2O2 model group compared to those of the control group (P<0.05). Following QCT treatment, these protein levels significantly decreased compared to those of the H2O2 model group (P<0.05). These results suggest that QCT may exert its protective effects against oxidative stress by modulating the p38 MAPK/NOX4 signaling pathway.

Conclusion

QCT has demonstrated significant protective effects against H2O2-induced oxidative damage in HESCs. This protection is primarily achieved through the effective reduction of ROS accumulation and the inhibition of critical signaling pathways involved in the oxidative stress response, notably the p38 MAPK/NOX4 pathway. The results of this study reveal that QCT's ability to modulate these pathways plays a key role in alleviating cellular damage associated with oxidative stress conditions. This indicates not only its potential as a protective agent against cellular oxidative stress, but also highlights its potential for therapeutic applications in treating conditions characterized by increased oxidative stress in the endometrium, thereby offering the prospect of enhancing reproductive health. Future studies should explore the long-term effects of QCT and its clinical efficacy in vivo, thereby providing a clear path toward its integration into therapeutic protocols.

Time-restricted feeding prevents ionizing radiation-induced hematopoietic stem cell damage by inhibiting NOX-4/ROS/p38 MAPK pathway

Ionizing radiation (IR)-induced damage to the hematopoietic system is a prominent symptom following exposure to total body irradiation (TBI). The exploration of strategies aimed at to mitigating radiation-induced hematopoietic damage assumes paramount importance. Time-restricted feeding (TRF) has garnered attention for its beneficial effects in various diseases. In this study, we evaluated the preventive effects of TRF on TBI-induced hematopoietic damage. The results suggested that TRF significantly enhanced the proportion and function of hematopoietic stem cells in mice exposed to 4 Gy TBI. These effects might be attributed to the inhibition of the NOX-4/ROS/p38 MAPK pathway in hematopoietic stem cells. TRF also influenced the expression of nuclear factor erythroid2-related factor 2 and increased glutathione peroxidase activity, thereby promoting the clearance of reactive oxygen species. Furthermore, TRF alleviated aberrations in plasma metabolism by inhibiting the mammalian target of rapamycin. These findings suggest that TRF may represent a novel approach to preventing hematopoietic radiation damage.

Traditional Chinese medicine inspired dual-drugs loaded inhalable nano-therapeutics alleviated idiopathic pulmonary fibrosis by targeting early inflammation and late fibrosis

Idiopathic pulmonary fibrosis (IPF) is a highly debilitating and fatal chronic lung disease that is difficult to cure clinically. IPF is characterized by a gradual decline in lung function, which leads to respiratory failure and severely affects patient quality of life and survival. Oxidative stress and chronic inflammation are believed to be important pathological mechanisms underlying the onset and progression of IPF, and the vicious cycle of NOX4-derived ROS, NLRP3 inflammasome activation, and p38 MAPK in pulmonary fibrogenesis explains the ineffectiveness of single-target or single-drug interventions. In this study, we combined astragaloside IV (AS-IV) and ligustrazine (LIG) based on the fundamental theory of traditional Chinese medicine (TCM) of "tonifying qi and activating blood" and loaded these drugs onto nanoparticles (AS_LIG@PPGC NPs) that were inhalable and could penetrate the mucosal barrier. Our results suggested that inhalation of AS_LIG@PPGC NPs significantly improved bleomycin-induced lung injury and fibrosis by regulating the NOX4-ROS-p38 MAPK and NOX4-NLRP3 pathways to treat and prevent IPF. This study not only demonstrated the superiority, feasibility, and safety of inhalation therapy for IPF intervention but also confirmed that breaking the vicious cycle of ROS and the NLRP3 inflammasome is a promising strategy for the successful treatment of IPF. Moreover, this successful nanoplatform is a good example of the integration of TCM and modern medicine.

Melatonin, a potentially effective drug for the treatment of infected bone nonunion

Osteomyelitis (OM), characterized by heterogeneity and complexity in treatment, has a high risk of infection recurrence which may cause limb disability. Management of chronic inactive osteomyelitis (CIOM) without typical inflammatory symptoms is a great challenge for orthopedic surgeons. On the basis of data analysis of 1091 OM cases, we reported that latent osteogenic decline in CIOM patients was the main cause of secondary surgery. Our research shows that impairment of osteoblasts capacity in CIOM patients is associated with ferroptosis of osteoblasts caused by internalization of Staphylococcus aureus. Further studies show that melatonin could alleviate ferroptosis of osteoblasts in infected states through Nox4/ROS/P38 axis and protect the osteogenic ability of CIOM patients. Knockout of NADPH oxidase 4 (Nox4) in vivo could effectively relieve ferroptosis of osteoblasts in the state of infection and promote osteogenesis. Through a large number of clinical data analyses combined with molecular experiments, this study clarified that occult osteogenic disorders in CIOM patients were related to ferroptosis of osteoblasts. We revealed that melatonin might be a potential therapeutic drug for CIOM patients and provided a new insight for the treatment of OM.

Chrysin-based supramolecular cyclodextrin-calixarene drug delivery system: a novel approach for attenuating cardiac fibrosis in chronic diabetes

Introduction: Cardiac fibrosis is strongly induced by diabetic conditions. Both chrysin (CHR) and calixarene OTX008, a specific inhibitor of galectin 1 (Gal-1), seem able to reduce transforming growth factor beta (TGF-β)/SMAD pro-fibrotic pathways, but their use is limited to their low solubility. Therefore, we formulated a dual-action supramolecular system, combining CHR with sulfobutylated β-cyclodextrin (SBECD) and OTX008 (SBECD + OTX + CHR). Here we aimed to test the anti-fibrotic effects of SBECD + OTX + CHR in hyperglycemic H9c2 cardiomyocytes and in a mouse model of chronic diabetes. Methods: H9c2 cardiomyocytes were exposed to normal (NG, 5.5 mM) or high glucose (HG, 33 mM) for 48 h, then treated with SBECD + OTX + CHR (containing OTX008 0.75-1.25-2.5 µM) or the single compounds for 6 days. TGF-β/SMAD pathways, Mitogen-Activated Protein Kinases (MAPKs) and Gal-1 levels were assayed by Enzyme-Linked Immunosorbent Assays (ELISAs) or Real-Time Quantitative Reverse Transcription Polymerase chain reaction (qRT-PCR). Adult CD1 male mice received a single intraperitoneal (i.p.) administration of streptozotocin (STZ) at a dosage of 102 mg/kg body weight. From the second week of diabetes, mice received 2 times/week the following i.p. treatments: OTX (5 mg/kg)-SBECD; OTX (5 mg/kg)-SBECD-CHR, SBECD-CHR, SBECD. After a 22-week period of diabetes, mice were euthanized and cardiac tissue used for tissue staining, ELISA, qRT-PCR aimed to analyse TGF-β/SMAD, extracellular matrix (ECM) components and Gal-1. Results: In H9c2 cells exposed to HG, SBECD + OTX + CHR significantly ameliorated the damaged morphology and reduced TGF-β1, its receptors (TGFβR1 and TGFβR2), SMAD2/4, MAPKs and Gal-1. Accordingly, these markers were reduced also in cardiac tissue from chronic diabetes, in which an amelioration of cardiac remodeling and ECM was evident. In both settings, SBECD + OTX + CHR was the most effective treatment compared to the other ones. Conclusion: The CHR-based supramolecular SBECD-calixarene drug delivery system, by enhancing the solubility and the bioavailability of both CHR and calixarene OTX008, and by combining their effects, showed a strong anti-fibrotic activity in rat cardiomyocytes and in cardiac tissue from mice with chronic diabetes. Also an improved cardiac tissue remodeling was evident. Therefore, new drug delivery system, which could be considered as a novel putative therapeutic strategy for the treatment of diabetes-induced cardiac fibrosis.

Artemisia gmelinii Extract Attenuates Particulate Matter-Induced Neutrophilic Inflammation in a Mouse Model of Lung Injury

Particulate matter (PM) induces and augments oxidative stress and inflammation, leading to respiratory diseases. Although Artemisia gmelinii Weber ex Stechm has antioxidant and anti-inflammatory effects, there are no reports on whether Artemisia gmelinii extract (AGE) regulates lung inflammation in a PM-induced model. Thus, we investigated the protective effects of AGE using a PM-induced mouse lung inflammation model. AGE significantly decreased the expression of inflammatory chemokines, neutrophil extracellular trap formation, and the total number of inflammatory cells in the bronchoalveolar lavage fluid (BALF). Furthermore, AGE attenuated lung inflammation through the suppression of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)/mitogen-activated protein kinase (MAPK) signaling pathway, while promoting the nuclear factor erythroid-2-related factor 2 (NRF2)/heme oxygenase-1 (HO-1) signaling pathway in lung tissues. Concordant with these observations, AGE suppressed inflammatory cytokines, chemokines, reactive oxygen species, NETosis, myeloperoxidase, and neutrophil elastase by decreasing the mRNA expression of High mobility group box 1, Runt-related transcription factor 1, and Kruppel-like factor 6 in differentiated HL-60 cells. In summary, our data demonstrated that AGE suppresses PM-induced neutrophil infiltration, lung damage, and pulmonary inflammation by suppressing NF-κB/MAPK signaling pathways and enhancing the NRF2/HO-1 signaling pathway. These findings suggest that AGE administration is an effective approach for preventing and treating PM-induced respiratory inflammation.

Overview of PM2.5 and health outcomes: Focusing on components, sources, and pollutant mixture co-exposure

PM_2.5 varies in source and composition over time and space as a complicated mixture. Consequently, the health effects caused by PM_2.5 varies significantly over time and generally exhibit significant regional variations. According to numerous studies, a notable relationship exists between PM_2.5 and the occurrence of many diseases, such as respiratory, cardiovascular, and nervous system diseases, as well as cancer. Therefore, a comprehensive understanding of the effect of PM_2.5 on human health is critical. The toxic effects of various PM_2.5 components, as well as the overall toxicity of PM_2.5 are discussed in this review to provide a foundation for precise PM_2.5 emission control. Furthermore, this review summarizes the synergistic effect of PM_2.5 and other pollutants, which can be used to draft effective policies.

Neuroprotective potential of biochanin-A and review of the molecular mechanisms involved

Biochanin-A is a naturally occurring plant phytoestrogen, which mimics specific the agonistic activity of estrogens. Biochanin-A is known to possess numerous activities, including neuroprotective, anti-diabetic, hepatoprotective, anti-inflammatory, antioxidant, and antimicrobial activities, along with the anticancer activity. Neuroinflammation is thought to play a pivotal pathological role in neurodegenerative disease. Sustained neuroinflammatory processes lead to progressive neuronal damage in Parkinson's and Alzheimer's disease. Activation of PI3K/Akt cascade and inhibition of MAPK signaling cascade have been observed to be responsible for conferring protection against neuroinflammation in neurodegenerative diseases. An increased oxidative stress promotes neuronal apoptosis via potentiating the TLR-4/NF-κB and inhibiting PI3K/Akt signaling mediated increase in pro-apoptotic and decreases in antiapoptotic proteins. Various authors have explored biochanin-A's neuroprotective effect by using various cell lines and animal models. Biochanin-A has been reported to mediate its neuroprotective via reducing the level of oxidants, inflammatory mediators, MAPK, TLR-4, NF-κB, NADPH oxidase, AchE, COX-2 and iNOS. Whereas, it has been observed to increase the level of anti-oxidants, along with phosphorylation of PI3K and Akt proteins. The current review has been designed to provide insights into the neuroprotective effect of biochanin-A and possible signaling pathways leading to protection against neuroinflammation and apoptosis in the central nervous system. This review will be helpful in guiding future researchers to further explore biochanin A at a mechanistic level to obtain useful lead molecules.

Specific upregulation of extracellular miR-6238 in particulate matter-induced acute lung injury and its immunomodulation

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are life-threatening diseases characterized by a severe inflammatory response and the destruction of alveolar epithelium and endothelium. ALI/ARDS is caused by pathogens and toxic environmental stimuli, such as particulate matter (PM). However, the general symptoms of ALI/ARDS are similar, and determining the cause of lung injury is often challenging. In this study, we investigated whether there is a critical miRNA that characterizes PM-induced ALI. We found that the expression of miR-6238 is specifically upregulated in lung tissue and lung-derived extracellular vesicles (EVs) in response to PM exposure. Notably, bacterial endotoxin (Lipopolysaccharide; LPS or peptidoglycan; PTG) does not induce the expression of miR-6238 in the lung. Instead, the expression of miR-155 is dramatically increased in LPS-induced ALI. We further demonstrated that human lung epithelial cells and macrophages predominantly produce miR-6238 and miR-155, respectively. Mechanistically, EV-miR-6238 is effectively internalized into alveolar macrophages (AMs) and regulates inflammatory responses in vivo. CXCL3 is a main target of miR-6238 in AMs and modulates neutrophil infiltration into the lung alveoli. Collectively, our findings suggest that miR-6238 is a novel regulator of pulmonary inflammation and a putative biomarker that distinguishes PM-induced ALI from endotoxin (LPS/PTG)-mediated ALI.

Biochemical evidence of PM2.5 critical components for inducing myocardial fibrosis in vivo and in vitro

PM_2.5 constituents are tightly linked to the initiation of many cardiovascular diseases (CVDs). Little is known, however, about the events which critical components of PM_2.5 can induce the initiating events in CVDs. C57BL/6 female mice were exposed to PM_2.5 (3 mg/kg b.w.) from four different cities (Taiyuan, Beijing, Hangzhou, and Guangzhou) by oropharyngeal aspiration every other day. PM_2.5 from Taiyuan increased the diastolic function of the hearts and induced myocardial fibrosis with increased areas of interstitial fibrosis through the NOX4/TGF-β1/Smad 3/Col1a1 pathways. Pb, Cr, Mn, Zn, and most of the polycyclic aromatic hydrocarbons (PAHs) were positively associated with the related indicators of cardiac diastolic function and myocardial fibrosis by using Pearson correlation (R² = 0.9085-0.9897). To determine the critical components in PM_2.5 that can induce the occurrence of myocardial fibrosis, BEAS-2b cells were treated with one or more of five candidate components with/without Guangzhou PM_2.5, and then the conditioned medium of BEAS-2b was used to culture AC16 cells. The results showed that Zn + Pb + Mn + BaP with PM_2.5 from Guangzhou exposure significantly increased reactive oxygen species production of BEAS-2b cells and induced a dramatic increase of myocardial fiber-related gene expression (Col1a1 and TGF-β) in AC16 cells. It indicated that the different mass concentrations of Zn, Pb, Mn, and ΣPAHs in PM_2.5 might be the critical factors that modulated myocardial fibrosis induction by targeted. Our study provided a novel avenue for further elucidation of molecular mechanisms of PM_2.5 components-induced myocardial fibrosis.

Dapagliflozin alleviates myocardial ischemia/reperfusion injury by reducing ferroptosis via MAPK signaling inhibition

Reperfusion is essential for ischemic myocardium but paradoxically leads to myocardial damage that worsens cardiac functions. Ferroptosis often occurs in cardiomyocytes during ischemia/reperfusion (I/R). The SGLT2 inhibitor dapagliflozin (DAPA) exerts cardioprotective effects independent of hypoglycemia. Here, we investigated the effect and potential mechanism of DAPA against myocardial ischemia/reperfusion injury (MIRI)-related ferroptosis using the MIRI rat model and hypoxia/reoxygenation (H/R)-induced H9C2 cardiomyocytes. Our results show that DAPA significantly ameliorated myocardial injury, reperfusion arrhythmia, and cardiac function, as evidenced by alleviated ST-segment elevation, ameliorated cardiac injury biomarkers including cTnT and BNP and pathological features, prevented H/R-triggered cell viability loss in vitro. In vitro and in vivo experiments showed that DAPA inhibited ferroptosis by upregulating the SLC7A11/GPX4 axis and FTH and inhibiting ACSL4. DAPA notably mitigated oxidative stress, lipid peroxidation, ferrous iron overload, and reduced ferroptosis. Subsequently, network pharmacology and bioinformatics analysis suggested that the MAPK signaling pathway was a potential target of DAPA and a common mechanism of MIRI and ferroptosis. DAPA treatment significantly reduced MAPK phosphorylation in vitro and in vivo, suggesting that DAPA might protect against MIRI by reducing ferroptosis through the MAPK signaling pathway.