Silica-exposed macrophages-secreted exosomal miR125a-5p induces Th1/Th2 and Treg/Th17 cell imbalance and promotes fibroblast transdifferentiation

OM85 ameliorates bleomycin-induced pulmonary fibrosis in mice by inhibiting Notch expression and modulating the IFN-γ/IL-4 ratio

Th1/Th2 balances may play a vital role in the processes of inflammation and fibrosis. The Th1/Th2 paradigm can be evaluated by representing IFN-γ for Th1 and IL-4 for Th2. OM-85 BV encouraged preferential development of the Th1-type immunity characterized by amplified IFN-γ and decreased IL-4 production. This study aimed to evaluate the inhibitory effect of OM85 on bleomycin (BLM)-induced pulmonary fibrosis in C57 and its possible mechanisms. In vitro experiments demonstrated that OM85 exhibited no significant toxicity to HELF cells. OM-85 inhibited the TGF-β1-induced protein expression of Notch1 and Hes1 and reduced the fibrosis-related marker profiles, such as collagen I, collagen III, fibronectin, P21, and α-SMA, following TGF-β1 treatment of these cells. Immunofluorescence also revealed that OM-85 decreased the expression of α-SMA induced by TGF-β1 in HELF cells. In the vivo experiments, a pulmonary fibrosis model was established by administering three intratracheal doses of BLM (1 mg/kg). The BLM-OM85 group was exposed to an aerosol containing 10.5 mg of OM-85 dissolved in 10 mL of sterile PBS on days 42, 44, 46, 49, 51, and 53. BLM-induced pulmonary fibrosis, leading to increased levels of lung hydroxyproline, total cell count, macrophages, neutrophils, lymphocytes, and the expression of TGF-β1 as well as Notch1 and Hes1 in lung tissue, along with fibrosis-associated proteins such as collagen I, collagen III, fibronectin, P21, and α-SMA. Additionally, the Th1 response was suppressed, as evidenced by decreased IFN-γ in the bronchoalveolar lavage fluid (BALF), while the Th2 response was amplified, marked by increased IL-4 levels in BALF. Moreover, morphological assessments showed that BLM caused increased Ashcroft scores, relative collagen content, and an expanded damaged area, as well as an increased optical density (OD) of collagen I. The administration of OM-85 significantly mitigated these effects. These findings suggest that OM-85 holds therapeutic potential for BLM-induced pulmonary fibrosis in female C57 mice, partly due to the inhibition of Notch1 and Hes1 expression and the modulation of the IFN-γ/IL-4 ratio.

Tripartite motif-containing 32 regulated by miR-6236-p5 inhibited silica-induced apoptosis of alveolar macrophages

Apoptosis of alveolar macrophages (AMs) induced by silica is one of the crucial driving factors of silicosis inflammation and fibrosis. However, the mechanism of silica-induced AMs apoptosis remains unclear. In this study, transcriptome sequencing identified 11 differentially expressed (DE)-mRNAs enriched in the regulation of apoptotic signaling pathways in AMs treated with 250 μg/mL silica for 24 h, of which tripartite motif-containing 32 (Trim32) was the most significant and down-regulated. The decreased Trim32 promoted AMs apoptosis, while Trim32 overexpression inhibited the apoptosis of AMs induced by silica at 250 μg/mL for 24 h. MiR-6236-p5 was then identified by MiRNA sequencing as the most significant DE-miRNA potentially regulating Trim32 expression, and the interaction between miR-6236-p5 and Trim32 3'-UTR was confirmed by dual luciferase reporter gene assay. Treated with 100 nM miR-6236-p5 inhibitor increased the expression of Trim32 and inhibited the apoptosis of AMs induced by silica at 250 μg/mL for 24 h, while miR-6236-p5 mimic promoted the apoptosis of silica-induced AMs. In conclusion, this study identified Trim32 regulated by miR-6236-p5 played an important role in silica-induced AMs apoptosis based on RNA sequencing, which provided a novel clue for exploring the mechanism of silica-induced AMs apoptosis.

Engineering Macrophage-Derived Exosome to Deliver Pirfenidone: A Novel Approach to Combat Silicotic Pulmonary Fibrosis

Silicosis is a severe lung disease characterized by diffuse pulmonary fibrosis, for which there is currently no effective treatment. Pirfenidone (PFD) shows great antifibrotic potential but is clinically hindered by low bioavailability and gastrointestinal side effects. To address these limitations, this study develops a PFD delivery system (PFD-Exo) using J774A.1 macrophage-derived exosomes. Firstly, PFD is loaded via sonication, then PFD-Exo is characterized using Raman spectral imaging and UV absorption spectroscopy. Finally, in vitro and in vivo silicosis models are established to evaluate its antifibrotic effects. Results show that PFD-Exo outperforms free PFD in inhibiting TGF-β1-induced transdifferentiation of primary lung fibroblasts in vitro. In a mouse model of silicosis, PFD-Exo is found to be accumulated in the lungs following intratracheal administration and significantly ameliorates pulmonary inflammation and fibrosis while minimizing gastrointestinal side effects. Mechanistic studies reveal that PFD-Exo modulates the TGF-β signaling pathway by downregulating SMAD3 and upregulating SMAD7 and NOGGIN. In conclusion, this study provides the first evidence of macrophage-derived exosomes as an effective PFD delivery system for silicosis treatment and offers a promising strategy for other refractory pulmonary diseases.

Hepatocellular Carcinoma Cells in Humans Exhibit Resistance to Suberoylanilide Hydroxamic Acid (SAHA) Owing to the Diminished Level of Hsa-miR-125a-5p

Hepatocellular carcinoma (HCC) presents an escalating public health challenge globally. However, drug resistance has emerged as a major impediment to successful HCC treatment, limiting the efficacy of curative interventions. Despite numerous investigations into the diverse impacts of hsa-miR-125a-5p on tumor growth across different cancer types, its specific involvement in chemotherapy resistance in HCC remains elusive. Our study aims to explore the potential involvement of hsa-miR-125a-5p in HCC drug resistance using HA22T cell lines: HA22T and HA22T-HDACi-resistance cells. The HA22T-HDACi-resistance cell line is an established liver cancer cell line that is resistant to histone deacetylase inhibitors (HDACi), apicidin, and suberoylanilide hydroxamic acid (SAHA). Utilizing qPCR, the levels of hsa-miR-125a-5p showed a notable decrease in the HA22T-HDACi-resistance cell line compared with HA22T cells. Subsequently, we examined the influence of hsa-miR-125a-5p expression on cell death in both cell lines. The findings demonstrated that alterations in hsa-miR-125a-5p levels directly impacted apoptosis in both HA22T and HA22T-HDACi-resistance cell lines with SAHA treatment. Afterwards, we recognized TRAF6 as a target gene of hsa-miR-125a-5p, shedding light on its potential role in modulating apoptosis via targeting TRAF6 in HCC. These findings underscore the potential significance of hsa-miR-125a-5p in overcoming drug resistance in HCC, offering insights into its dual role in apoptosis modulation and TRAF6 targeting. The study suggests that hsa-miR-125a-5p may inhibit expression of TRAF6 in HCC, presenting a promising avenue for gene therapy in HCC with HDACi resistance.

Quercetin Protects against Silicon dioxide Particles-induced spleen ZBP1-Mediated PANoptosis by regulating the Nrf2/Drp1/mtDNA axis

Silicon dioxide particles (SiO2) are a widely used novel material, and SiO2 that enter the body can accumulate in the spleen and cause spleen injury. Quercetin (Que) has a strong antioxidant activity and can also regulate and improve immune function, but whether Que can improve SiO2-induced spleen injury and its underlying mechanism remain to be explored. Herein, we established a C57BL/6 mice model with SiO2 exposure (10 mg/kg) and treated with Que (25 mg/kg). We also cultured CTLL-2 cells for in vitro experiments. Studies in vivo and in vitro showed that SiO2 exposure caused oxidative stress and mitochondrial dynamics disorder, which led to decrease of mitochondrial membrane potential (ΔΨm) and mitochondrial DNA (mtDNA) leakage. mtDNA was recognized by Z-DNA binding protein 1 (ZBP1) in the cytoplasm and increased the expression of ZBP1. This process further promoted the assembly of the ZBP1-mediated PANoptosome, which subsequently induced PANoptosis. Interestingly, supplementation with Que significantly reversed these changes. Specifically, Que mitigated spleen ZBP-1 mediated PANoptosis through preventing mtDNA leakage via regulating nuclear factor erythroid 2-related factor 2/reactive oxygen species/dynamin-related protein 1 (Nrf2/ROS/Drp1) axis. This study enriches the understanding of the toxicological mechanisms of SiO2 and provides evidence for the protective effects of Que against SiO2-induced splenic toxicity.

The role of macrophage-derived exosomes in noncancer liver diseases: From intercellular crosstalk to clinical potential

Chronic liver disease has a substantial global prevalence and mortality rate. Macrophages, pivotal cells in innate immunity, exhibit remarkable heterogeneity and plasticity and play a considerable role in maintaining organ homeostasis, modulating inflammatory responses, and influencing disease progression in the liver. Exosomes, which can serve as conduits for intercellular communication, biomarkers, and therapeutic targets for a spectrum of diseases, have recently garnered increasing attention recently. Given that the liver is the organ with the highest macrophage content, a thorough understanding of the influence of macrophage-derived exosomes (MDEs) on noncancer liver disease pathogenesis and their potential therapeutic applications is paramount. Interactions among MDEs, hepatocytes, hepatic stellate cells (HSCs), and other nonparenchymal cells constitute a complex network regulates liver immune homeostasis. In this review, we summarize the latest progress in the current understanding of MDE heterogeneity and cellular crosstalk in noncancer liver diseases, as well as their potential clinical applications. Additionally, challenges and future directions are underscored.

Revisiting the role of MicroRNAs in the pathogenesis of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a prevalent chronic pulmonary fibrosis disease characterized by alveolar epithelial cell damage, fibroblast proliferation and activation, excessive extracellular matrix deposition, and abnormal epithelial-mesenchymal transition (EMT), resulting in tissue remodeling and irreversible structural distortion. The mortality rate of IPF is very high, with a median survival time of 2-3 years after diagnosis. The exact cause of IPF remains unknown, but increasing evidence supports the central role of epigenetic changes, particularly microRNA (miRNA), in IPF. Approximately 10% of miRNAs in IPF lung tissue exhibit differential expression compared to normal lung tissue. Diverse miRNA phenotypes exert either a pro-fibrotic or anti-fibrotic influence on the progression of IPF. In the context of IPF, epigenetic factors such as DNA methylation and long non-coding RNAs (lncRNAs) regulate differentially expressed miRNAs, which in turn modulate various signaling pathways implicated in this process, including transforming growth factor-β1 (TGF-β1)/Smad, mitogen-activated protein kinase (MAPK), and phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) pathways. Therefore, this review presents the epidemiology of IPF, discusses the multifaceted regulatory roles of miRNAs in IPF, and explores the impact of miRNAs on IPF through various pathways, particularly the TGF-β1/Smad pathway and its constituent structures. Consequently, we investigate the potential for targeting miRNAs as a treatment for IPF, thereby contributing to advancements in IPF research.

Radiation-induced fibrosis: Mechanisms and therapeutic strategies from an immune microenvironment perspective

Radiation-induced fibrosis (RIF) is a severe chronic complication of radiotherapy (RT) manifested by excessive extracellular matrix (ECM) components deposition within the irradiated area. The lung, heart, skin, jaw, pelvic organs and so on may be affected by RIF, which hampers body functions and quality of life. There is accumulating evidence suggesting that the immune microenvironment may play a key regulatory role in RIF. This article discussed the synergetic or antagonistic effects of immune cells and mediators in regulating RIF's development. Several potential preventative and therapeutic strategies for RIF were proposed based on the immunological mechanisms to provide clinicians with improved cognition and clinical treatment guidance.

The role of macrophage-derived Exosomes in reversing peritoneal fibrosis: Insights from Astragaloside IV

BACKGROUND

Peritoneal dialysis (PD) is a successful renal replacement therapy for end-stage renal disease. Long-term PD causes mesothelial-mesenchymal transition (MMT) of peritoneal mesothelial cells (PMCs), leading to peritoneal fibrosis (PF), which reduces the efficiency of PD. Macrophages are thought to play a role in the onset and perpetuation of peritoneal injury. However, the mechanisms by which macrophages-PMCs communication regulates peritoneal fibrosis are not fully understood resulting in a lack of disease-modifying drugs. Astragaloside IV (AS-IV) possessed anti-fibrotic effect towards PF in PD whereas the mechanistic effect of AS-IV in PD is unknown.

METHODS

The primary macrophages were extracted and treated with LPS or AS-IV, then co-cultured with primary PMCs in transwell plates. The macrophage-derived exosomes were extracted and purified by differential centrifugation, then co-cultured with primary PMCs. Small RNA-seq was used to detect differential miRNAs in exosomes, and then KEGG analysis and q-PCR were performed for validation. In vivo PD rat models were established by inducing with high-glucose peritoneal dialysis fluid and different concentrations of AS-IV and exosomes were intraperitoneal injection. Through qRT-PCR, western blotting, and luciferase reporting, candidate proteins and pathways were validated in vivo and in vitro. The functions of the validated pathways were further investigated using the mimic or inhibition strategy. PF and inflammatory situations were assessed.

RESULTS

We found AS-IV reversed the MMT of PMCs caused by LPS-stimulated macrophages and the improving effect was mediated by macrophage-derived exosomes in vitro. We also demonstrated that AS-IV significantly reduced the MMT of PMCs in vitro or PF in a rat PD model via regulating exosome-contained miR-204-5p which targets Foxc1/β-catenin signaling pathway.

CONCLUSION

AS-IV attenuates macrophage-derived exosomes induced fibrosis in PD through the miR-204-5p/Foxc1 pathway.

Trigonelline hydrochloride attenuates silica-induced pulmonary fibrosis by orchestrating fibroblast to myofibroblast differentiation

BACKGROUND

Silicosis represents a paramount occupational health hazard globally, with its incidence, morbidity, and mortality on an upward trajectory, posing substantial clinical dilemmas due to limited effective treatment options available. Trigonelline (Trig), a plant alkaloid extracted mainly from coffee and fenugreek, have diverse biological properties such as protecting dermal fibroblasts against ultraviolet radiation and has the potential to inhibit collagen synthesis. However, it's unclear whether Trig inhibits fibroblast activation to attenuate silicosis-induced pulmonary fibrosis is unclear.

METHODS

To evaluate the therapeutic efficacy of Trig in the context of silicosis-related pulmonary fibrosis, a mouse model of silicosis was utilized. The investigation seeks to elucidated Trig's impact on the progression of silica-induced pulmonary fibrosis by evaluating protein expression, mRNA levels and employing Hematoxylin and Eosin (H&E), Masson's trichrome, and Sirius Red staining. Subsequently, we explored the mechanism underlying of its functions.

RESULTS

In vivo experiment, Trig has been demonstrated the significant efficacy in mitigating SiO2-induced silicosis and BLM-induced pulmonary fibrosis, as evidenced by improved histochemical staining and reduced fibrotic marker expressions. Additionally, we showed that the differentiation of fibroblast to myofibroblast was imped in Trig + SiO2 group. In terms of mechanism, we obtained in vitro evidence that Trig inhibited fibroblast-to-myofibroblast differentiation by repressing TGF-β/Smad signaling according to the in vitro evidence. Notably, our finding indicated that Trig seemed to be safe in mice and fibroblasts.

CONCLUSION

In summary, Trig attenuated the severity of silicosis-related pulmonary fibrosis by alleviating the differentiation of myofibroblasts, indicating the development of novel therapeutic approaches for silicosis fibrosis.

Nano-enabled delivery of diosgenin and emodin ameliorates respirable silica dust-induced pulmonary fibrosis silicosis in rats

Oxidative stress and inflammation play a fundamental role in the beginning and advancement of silicosis. Hence, questing active phytocompounds (APCs) with anti-oxidative and anti-inflammatory properties such as diosgenin (DG) and emodin (ED) can be a therapeutic intervention targeting silica-induced pulmonary inflammation and fibrosis. Hydrophobicity and low bioavailability are the barriers that restrict the therapeutic efficacy of DG and ED against pulmonary defects. Encapsulating these APCs in polymeric nanoparticles can overcome this limitation. The present study has thus explored the anti-inflammatory and anti-fibrotic effects of polylactic-co-glycolic acid (PLGA) nanoparticles (NPs) individually loaded with DG (DGn) or ED (EDn) and in combine DG+ED [(DG+ED)n] in respirable silica dust (RSD)-induced pulmonary fibrosis silicosis rat model. Our study found that individual and combined NPs revealed physiochemical characteristics appropriate for IV administration with sustained-drug release purposes. Physiological evaluations of RSD-induced silicosis rats suggested that no treatment could improve the body weight. Still, they reduced the lung coefficient by maintaining lung moisture. Only (DG+ED)n significantly cleared free lung silica. All interventions were found to attribute the increased per cent cell viability in BALF, reduce cytotoxicity via minimizing LDH levels, and balance the oxidant-antioxidant status in silicotic rats. The expression of inflammatory cytokines (TNF-α, IL-1β, IL-6, MCP-1, and TGF-β1) were efficiently down-regulated with NPs interventions compared to pure (DG+ED) treatment. All drug treatments significantly declined, the 8-HdG and HYP productions indicate that RSD-induced oxidative DNA damage and collagen deposition were successfully repaired. Moreover, histopathological investigations proposed that individual or combined drugs NPs interventions could decrease the fibrosis and alveolitis grades in RSD-induced silicosis rats. However, (DG+ED)n intervention significantly inhibited pulmonary fibrosis and alveolitis compared to pure (DG+ED) treatment. In conclusion, the RSD can induce oxidative stress and inflammation in rats, producing reactive oxygen species (ROS)-mediated cytotoxicity to pulmonary cells and leading to silicosis development. The IV administration of combined NP suppressed lung inflammation and collagen formation by maintaining oxidant-antioxidant status and effectively interrupting the fibrosis-silicosis progression. These results may be attributed to the improved bioavailability of DG and ED through their combined nano-encapsulation-mediated targeted drug delivery.

Exposure to micron-grade silica particles triggers pulmonary fibrosis through cell-to-cell delivery of exosomal miR-107

Long-term exposure to inhalable silica particles may lead to severe systemic pulmonary disease, such as silicosis. Exosomes have been demonstrated to dominate the pathogenesis of silicosis, but the underlying mechanisms remain unclear. Therefore, this study aimed to explore the roles of exosomes by transmitting miR-107, which has been linked to the toxic pulmonary effects of silica particles. We found that miR-107, miR-122-5p, miR-125a-5p, miR-126-5p, and miR-335-5p were elevated in exosomes extracted from the serum of patients with silicosis. Notably, an increase in miR-107 in serum exosomes and lung tissue was observed in the experimental silicosis mouse model, while the inhibition of miR-107 reduced pulmonary fibrosis. Moreover, exosomes helped the migration of miR-107 from macrophages to lung fibroblasts, triggering the transdifferentiation of cell phenotypes. Further experiments demonstrated that miR-107 targets CDK6 and suppresses the expression of retinoblastoma protein phosphorylation and E2F1, resulting in cell-cycle arrest. Overall, micron-grade silica particles induced lung fibrosis through exosomal miR-107 negatively regulating the cell cycle signaling pathway. These findings may open a new avenue for understanding how silicosis is regulated by exosome-mediated cell-to-cell communication and suggest the prospect of exosomes as therapeutic targets.