Silibinin alleviates silica-induced pulmonary fibrosis: Potential role in modulating inflammation and epithelial-mesenchymal transition

Gut microbiome and metabolome profiling in coal workers' pneumoconiosis: potential links to pulmonary function

Coal workers' pneumoconiosis (CWP) is a severe occupational disease resulting from prolonged exposure to coal dust. However, its pathogenesis remains elusive, compounded by a lack of early detection markers and effective treatments. Although the impact of gut microbiota on lung diseases is acknowledged, its specific role in CWP is unclear. This study aims to explore changes in the gut microbiome and metabolome in CWP, while also assessing the correlation between gut microbes and alterations in lung function. Fecal specimens from 43 CWP patients and 48 dust-exposed workers (DEW) were examined using 16S rRNA gene sequencing for microbiota and liquid chromatography-mass spectrometry for metabolite profiling. We observed similar gut microbial α-diversity but significant differences in flora composition (β-diversity) between patients with CWP and the DEW group. After adjusting for age using multifactorial linear regression analysis (MaAsLin2), the distinct gut microbiome profile in CWP patients revealed an increased presence of pro-inflammatory microorganisms such as Klebsiella and Haemophilus. Furthermore, in CWP patients, alterations in gut microbiota-particularly reduced α-diversity and changes in microbial composition-were significantly correlated with impaired pulmonary function, a relationship not observed in DEW. This underscores the specific impact of gut microbiota on pulmonary health in individuals with CWP. Metabolomic analysis of fecal samples from CWP patients and DEW identified 218 differential metabolites between the two groups, with a predominant increase in metabolites in CWP patients, suggesting enhanced metabolic activity in CWP. Key altered metabolites included various lipids, amino acids, and organic compounds, with silibinin emerging as a potential biomarker. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis linked these metabolites to pathways relevant to the development of pulmonary fibrosis. Additionally, studies on the interaction between microbiota and metabolites showed positive correlations between certain bacteria and increased metabolites in CWP, further elucidating the complex interplay in this disease state. Our findings suggest a potential contributory role of gut microbiota in CWP pathogenesis through metabolic regulation, with implications for diagnostic biomarkers and understanding disease mechanisms, warranting further molecular investigation.

IMPORTANCE

The findings have significant implications for the early diagnosis and treatment of coal workers' pneumoconiosis, highlighting the potential of gut microbiota as diagnostic biomarkers. They pave the way for new research into gut microbiota-based therapeutic strategies, potentially focusing on modifying gut microbiota to mitigate disease progression.

Berberine attenuates ECM accumulation and the progression of acute liver failure through inhibition of NLRP3 inflammasome signalling

Acute liver failure (ALF) is a life-threatening disease, characterized by upregulated extracellular matrix deposition and inflammatory signalling, with no effective treatment options and targets. The present study was designed to investigate the preventive and therapeutic effects of berberine (BBR) and its underlying mechanism in thioacetamide (TAA)-induced ALF. Male SD rats were administered with TAA 300 mg/kg, i.p., thrice to induce ALF and pre- or post-treated with BBR. To decipher the effects of BBR LFT markers, histopathological analysis of key fibrotic and inflammatory proteins was performed. In addition, the levels of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α were assessed by ELISA. Our work showed TAA-induced ALF animals were associated with increased ALT, AST, bilirubin (LFT markers) and histopathological alterations with profuse infiltration of inflammatory cells in the liver tissue. Treatment with BBR has significantly inhibited LFT markers and histological alterations triggered by TAA. In addition, TAA animals demonstrated increased collagen accumulation and upregulated expression of TGF-β1, vimentin, and α-SMA compared to control. The excessive accumulation of collagen, TGF-β1, vimentin, and α-SMA were significantly modulated with BBR treatment. Further, the fluorescence intensity of ROS an activator of NLRP3 including the NLRP3 inflammasome, and its downstream signalling ASC, cleaved IL-1β, and other pro-inflammatory cytokines like TNF-α and IL-6 stimulated by TAA were attenuated by BBR treatment. The current work indicated that BBR significantly ameliorated TAA-induced ALF by inhibiting the extracellular matrix accumulation associated with the NLRP3/IL-1β signalling pathway and could be a viable therapeutic option to treat ALF and other fibroinflammatory diseases.

Peptidyl arginine deiminase-4 inhibitor ameliorates pulmonary fibrosis through positive regulation of developmental endothelial locus-1

Recurring lung injury, chronic inflammation, aberrant tissue repair and impaired tissue remodelling contribute to the pathogenesis of pulmonary fibrosis (PF). Neutrophil extracellular traps (NETs) are released by activated neutrophils to trap, immobilise and kill invading pathogen and is facilitated by peptidyl arginine deiminase-4 (PAD-4). Dysregulated NETs release and abnormal PAD-4 activation plays a crucial role in activating pro-fibrotic events in PF. Developmental endothelial locus-1 (Del-1), expressed by the endothelial cells of lungs and brain acts as an endogenous inhibitor of inflammation and fibrosis. We have hypothesised that PAD-4 inhibitor exerts anti-inflammatory and anti-fibrotic effects in mice model of PF. We have also hypothesised by PAD-4 regulated the transcription of Del-1 through co-repression and its inhibition potentiates anti-fibrotic effects of Del-1. In our study, the PAD-4 inhibitor chloro-amidine (CLA) demonstrated anti-NETotic and anti-inflammatory effects in vitro in differentiated HL-60 cells. In a bleomycin-induced PF mice model, CLA administration in two doses (3 mg/kg, I.P and 10 mg/kg, I.P) improved lung function, normalized bronchoalveolar lavage fluid parameters, and attenuated fibrotic events, including markers of extracellular matrix and epithelial-mesenchymal transition. Histological analyses confirmed the restoration of lung architecture and collagen deposition with CLA treatment. ELISA, IHC, IF, RT-PCR, and immunoblot analysis supported the anti-NETotic effects of CLA. Furthermore, BLM-induced PF reduced Del-1 and p53 expression, which was normalized by CLA treatment. These findings suggest that inhibition of PAD-4 results in amelioration of PF in animal model and may involve modulation of Del-1 and p53 pathways, warranting further investigation.

RELA-mediated upregulation of LINC03047 promotes ferroptosis in silica-induced pulmonary fibrosis via SLC39A14

Long non-coding RNAs play a key role in silicosis, a fatal fibrotic lung disease, and there is an urgent need to develop new treatment targets. Long intergenic non-protein-coding RNA 3047 (LINC03047) is associated with cancer, but its role and mechanism in the progression of silicosis require further elucidation. This study investigated the function of LINC03047 in the epithelial-mesenchymal transition (EMT) during silicosis progression. LINC03047 expression was upregulated in SiO2-treated BEAS-2B and A549 cells, promoting SiO2-induced ferroptosis and subsequent EMT. Moreover, knockdown of LINC03047 significantly decreased the expression of solute carrier family 39 member 14 (SLC39A14), a ferrous iron transporter, and inhibition of SLC39A14 alleviated the ferroptosis and EMT caused by LINC03047 overexpression. We further investigated that NF-κB p65 (RELA) was critical for LINC03047 transcription in SiO2-treated BEAS-2B and A549 cells. In vivo experiments showed that SLC39A14 deficiency improved SiO2-induced lipid peroxidation and EMT. Collectively, our study reveals the function of the RELA/LINC03047/SLC39A14 axis in SiO2-induced ferroptosis and EMT, thereby contributing to the identification of novel drug targets for silicosis therapy.

Silibinin attenuates TGF-β2-induced fibrogenic changes in human trabecular meshwork cells by targeting JAK2/STAT3 and PI3K/AKT signaling pathways

Transforming growth factor-β2 (TGF-β2) induced fibrogenic changes in human trabecular meshwork (HTM) cells have been implicated in trabecular meshwork (TM) damage and intraocular pressure (IOP) elevation in primary open-angle glaucoma (POAG) patients. Silibinin (SIL) exhibited anti-fibrotic properties in various organs and tissues. This study aimed to assess the effects of SIL on the TGF-β2-treated HTM cells and to elucidate the underlying mechanisms. Our study found that SIL effectively inhibited HTM cell proliferation, attenuated TGF-β2-induced cell migration, and mitigated TGF-β2-induced reorganization of both actin and vimentin filaments. Moreover, SIL suppressed the expressions of fibronectin (FN), collagen type I alpha 1 chain (COL1A1), and alpha-smooth muscle actin (α-SMA) in the TGF-β2-treated HTM cells. RNA sequencing indicated that SIL interfered with the phosphoinositide 3-kinase (PI3K)/protein kinase B (PKB, also known as AKT) signaling pathway, extracellular matrix (ECM)-receptor interaction, and focal adhesion in the TGF-β2-treated HTM cells. Western blotting demonstrated SIL inhibited the activation of Janus kinase 2 (JAK2)/signal transducers and activators of transcription 3 (STAT3) and the downstream PI3K/AKT signaling pathways induced by TGF-β2, potentially contributing to its inhibitory effects on ECM protein production in the TGF-β2-treated HTM cells. Our study demonstrated the ability of SIL to inhibit TGF-β2-induced fibrogenic changes in HTM cells. SIL could be a potential IOP-lowering agent by reducing the fibrotic changes in the TM tissue of POAG patients, which warrants further investigation through additional animal and clinical studies.

Oral arsenite exposure induces inflammation and apoptosis in pulmonary tissue: acute and chronic evaluation in young and adult mice

Inorganic arsenic is a well-known environmental toxicant, and exposure to this metalloid is strongly linked with severe and extensive toxic effects in various organs including the lungs. In the present study, we aimed to investigate the acute and chronic effects of arsenite exposure on pulmonary tissue in young and adult mice. In brief, young and adult female Balb/C mice were exposed to 3 and 30 ppm arsenite daily via drinking water for 30 and 90 days. Subsequently, the animals were sacrificed and various histological and immunohistochemistry (IHC) analyses were performed using lung tissues. Our findings showed arsenite was found to cause dose-dependent pathological changes such as thickening of the alveolar septum, inflammatory cell infiltrations and lung fibrosis in young and adult mice. In addition, arsenite exposure significantly increased the expression of inflammatory markers NF-κB and TNF-α, indicating that arsenite-exposed mice suffered from severe lung inflammation. Moreover, the IHC analysis of fibrotic proteins demonstrated an increased expression of TGF-β1, α-SMA, vimentin and collagen-I in the arsenite-exposed mice compared to the control mice. This was accompanied by apoptosis, which was indicated by the upregulated expression of caspase-3 in arsenite-exposed mice compared to the control. Adult mice were generally found to be more prone to arsenite toxicity during chronic exposure relative to their younger counterparts. Overall, our findings suggest that arsenite in drinking water may induce dose-dependent and age-dependent structural and functional impairment in the lungs through elevating inflammation and fibrotic proteins.

Protective effects of Tinospora cordifolia miers extract against hepatic and neurobehavioral deficits in thioacetamide-induced hepatic encephalopathy in rats via modulating hyperammonemia and glial cell activation

ETHNOPHARMACOLOGICAL RELEVANCE

Tinospora cordifolia (TC) a potential medicinal herb, has been ethnobotanically used as an eco-friendly supplement to manage various diseases, including cerebral fever. Earlier studies have shown that TC exhibits diverse beneficial effects, including hepatoprotective and neuroprotective effects. However, the effects of TC remain unexplored in animal models of encephalopathy including hepatic encephalopathy (HE).

AIM OF THE STUDY

To evaluate the effects of TC stem extract against thioacetamide (TAA)-induced behavioural and molecular alterations in HE rats.

METHODS AND MATERIALS

The extract was preliminarily screened through phytochemical and HR-LC/MS analysis. Animals were pre-treated with TC extract at doses 30 and 100 mg/kg, orally. Following 7 days of TC pre-treatment, HE was induced by administering TAA (300 mg/kg, i. p. thrice). Behavioural assessments were performed after 56 h of TAA first dose. The animals were then sacrificed to assess biochemical parameters in serum, liver and brain. Liver tissue was used for immunoblotting and histological studies to evaluate inflammatory and fibrotic signalling. Moreover, brain tissue was used to evaluate brain edema, activation of glial cells (GFAP, IBA-1) and NF-κB/NLRP3 downstream signalling via immunoblotting and immunohistochemical analysis in cortex and hippocampus.

RESULTS

The pre-treatment with TC extract effective mitigated TAA-induced behavioural alterations, lowered serum LFT (AST, ALT, ALP, bilirubin) and oxidative stress markers in liver and brain. TC treatment significantly modulated hyperammonemia, cerebral edema and preserved the integrity of BBB proteins in HE animals. TC treatment attenuated TAA-induced histological changes, tissue inflammation (pNF-κB (p65), TNF-α, NLRP3) and fibrosis (collagen, α-SMA) in liver. In addition, immunoblotting analysis revealed TC pre-treatment inhibited fibrotic proteins such as vimentin, TGF-β1 and pSmad2/3 in the liver. Our study further showed that TC treatment downregulated the expression of MAPK/NF-κB inflammatory signalling, as well as GFAP and IBA-1 (glial cell markers) in cortex and hippocampus of TAA-intoxicated rats. Additionally, TC-treated animals exhibited reduced expression of caspase3/9 and BAX induced by TAA.

CONCLUSION

This study revealed promising insights on the protective effects of TC against HE. The findings clearly demonstrated that the significant inhibition of MAPK/NF-κB signalling and glial cell activation could be responsible for the observed beneficial effects of TC in TAA-induced HE rats.

Silymarin and Inflammation: Food for Thoughts

Inflammation is a vital defense mechanism, creating hostile conditions for pathogens, preventing the spread of tissue infection and repairing damaged tissues in humans and animals. However, when inflammation resolution is delayed or compromised as a result of its misregulation, the process proceeds from the acute phase to chronic inflammation, leading to the development of various chronic illnesses. It is proven that redox balance disturbances and oxidative stress are among major factors inducing NF-κB and leading to over-inflammation. Therefore, the anti-inflammatory properties of various natural antioxidants have been widely tested in various in vitro and in vivo systems. Accumulating evidence indicates that silymarin (SM) and its main constituent silibinin/silybin (SB) have great potential as an anti-inflammation agent. The main anti-inflammatory mechanism of SM/SB action is attributed to the inhibition of TLR4/NF-κB-mediated signaling pathways and the downregulated expression of pro-inflammatory mediators, including TNF-α, IL-1β, IL-6, IL-12, IL-23, CCL4, CXCL10, etc. Of note, in the same model systems, SM/SB was able to upregulate anti-inflammatory cytokines (IL-4, IL-10, IL-13, TGF-β, etc.) and lipid mediators involved in the resolution of inflammation. The inflammatory properties of SM/SB were clearly demonstrated in model systems based on immune (macrophages and monocytes) and non-immune (epithelial, skin, bone, connective tissue and cancer) cells. At the same time, the anti-inflammatory action of SM/SB was confirmed in a number of in vivo models, including toxicity models, nonalcoholic fatty liver disease, ischemia/reperfusion models, stress-induced injuries, ageing and exercising models, wound healing and many other relevant model systems. It seems likely that the anti-inflammatory activities of SM/SB are key elements on the health-promoting properties of these phytochemicals.

A systematic review of the research progress of traditional Chinese medicine against pulmonary fibrosis: from a pharmacological perspective

Pulmonary fibrosis is a chronic progressive interstitial lung disease caused by a variety of etiologies. The disease can eventually lead to irreversible damage to the lung tissue structure, severely affecting respiratory function and posing a serious threat to human health. Currently, glucocorticoids and immunosuppressants are the main drugs used in the clinical treatment of pulmonary fibrosis, but their efficacy is limited and they can cause serious adverse effects. Traditional Chinese medicines have important research value and potential for clinical application in anti-pulmonary fibrosis. In recent years, more and more scientific researches have been conducted on the use of traditional Chinese medicine to improve or reduce pulmonary fibrosis, and some important breakthroughs have been made. This review paper systematically summarized the research progress of pharmacological mechanism of traditional Chinese medicines and their active compounds in improving or reducing pulmonary fibrosis. We conducted a systematic search in several main scientific databases, including PubMed, Web of Science, and Google Scholar, using keywords such as idiopathic pulmonary fibrosis, pulmonary fibrosis, interstitial pneumonia, natural products, herbal medicine, and therapeutic methods. Ultimately, 252 articles were included and systematically evaluated in this analysis. The anti-fibrotic mechanisms of these traditional Chinese medicine studies can be roughly categorized into 5 main aspects, including inhibition of epithelial-mesenchymal transition, anti-inflammatory and antioxidant effects, improvement of extracellular matrix deposition, mediation of apoptosis and autophagy, and inhibition of endoplasmic reticulum stress. The purpose of this article is to provide pharmaceutical researchers with information on the progress of scientific research on improving or reducing Pulmonary fibrosis with traditional Chinese medicine, and to provide reference for further pharmacological research.

Treatment of Idiopathic Pulmonary Fibrosis by Inhaled Silybin Dry Powder Prepared via the Nanosuspension Spray Drying Technology

Idiopathic pulmonary fibrosis (IPF) is a kind of life-threatening interstitial lung disease characterized by progressive dyspnea with accurate pathogenesis unknown. At present, heat shock protein inhibitors are gradually used to treat IPF. Silybin, a heat shock protein C-terminal inhibitor, has high safety and good application prospects. In this work, we have developed a silybin powder able to be used for inhalation administration for the treatment of IPF. Silybin powder was prepared by the spray drying method and identified using cascade impactometry, particle size, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. A rat model of bleomycin-induced IPF was used to assess the effect of inhaled silybin spray-dried powder. Lung hydroxyproline content, wet weight, histology, inflammatory factor expression, and gene expression were examined. The results showed that inhaled silybin spray-dried powder alleviated inflammation and fibrosis, limited hydroxyproline accumulation in the lungs, modulated gene expression in the development of IPF, and improved postoperative survival. The results of this study suggest that silybin spray-dried powder is an attractive candidate for the treatment of IPF.

Silica-associated lung disease in developing countries

PURPOSE OF REVIEW

There is a considerable burden of silica-associated lung diseases in the developing world. This review summarizes the epidemiology of these diseases, especially silicosis and silico-tuberculosis, mitigative efforts and treatment, especially in the context of developing countries.

RECENT FINDINGS

In 2017, the highest incidence of silicosis was in China, India and Brazil among the developing countries. The prevalence of silicosis amongst exposed workers may vary from 4 to 55%; there is a risk of underestimation because of the 'healthy worker effect'. The permissible exposure limit for respirable silica adopted by governments in developing countries remains higher than the proposed 0.025 mg/m3. Silica exposure in informal or unorganized industries is challenging, as it falls outside statutory controls. Recent efforts on regulation and compensation by various governments in developing countries are encouraging but need proper implementation on the ground. Biomarkers such as club cell protein 16 and imaging methods such as computed tomography may offer earlier and easier detection of silicosis. Advanced silicosis remains incurable; novel treatments such as antifibrotics agents may be potentially effective.

SUMMARY

Silica-associated lung diseases are prevalent in developing countries. Efforts directed at preventing or minimizing exposure to respirable crystalline silica are required for mitigation.

Silibinin Attenuates Experimental Periodontitis by Downregulation of Inflammation and Oxidative Stress

Periodontitis is an oral microbiota-induced inflammatory disease, in which inflammation and oxidative stress play a critical role. Silibinin (SB), a Silybum marianum-derived compound, exhibits strong anti-inflammatory and antioxidative properties. We adopted a rat ligature-induced periodontitis model and a lipopolysaccharide- (LPS-) stimulated human periodontal ligament cells (hPDLCs) model to evaluate the protective effects of SB. In the in vivo model, SB reduced alveolar bone loss and apoptosis of PDLCs in the periodontal tissue. SB also maintained the expression of nuclear factor-E2-related factor 2 (Nrf2), a key regulator of cellular resistance to oxidative stress, and attenuated lipid, protein, and DNA oxidative damages in the periodontal lesion area. Meanwhile, in the in vitro model, SB administration reduced the production of intracellular reactive oxidative species (ROS). Furthermore, SB exerted a strong anti-inflammatory property in both in vivo and in vitro models by inhibiting the expression of inflammatory mediators including nuclear factor-κB (NF-κB) as well as nucleotide binding oligomerization domain- (NOD-) like receptor family pyrin domain-containing 3 (NLRP3) and downregulating the levels of proinflammatory cytokines. This study, for the first time, demonstrates that SB exhibits the anti-inflammatory and antioxidative properties against periodontitis by downregulating the expression of NF-κB and NLRP3 and upregulating Nrf2 expression, suggesting a promising potential clinical application of SB in periodontitis.

Melatonin ameliorates chronic copper-induced lung injury

Copper (Cu) is an important trace element required for several biological processes. The use of copper is increasing gradually in several applications. Previous studies suggest that excess levels of copper are attributed to induce oxidative stress and inflammation, mediating tissue damage. Inline, melatonin the hormone of darkness has been reported to exhibit various therapeutic effects including strong free radical scavenging properties and anti-inflammatory effects. However, its effects against pulmonary injury promoted by copper are not explored and remain unclear so far. Therefore, the present study was aimed to investigate the protective effect of melatonin against copper-induced lung damage. Female Sprague Dawley (SD) rats were exposed to 250 ppm of copper in drinking water for 16 weeks and treated with melatonin (i.p.) 5 and 10 mg/kg from the week (13-16th). The extent of tissue damage was assessed by tissue oxidative stress parameters, metal estimation and histological analysis. Copper-challenged rats showed altered oxidative stress variables. In addition, metal analysis revealed increased copper accumulation in the lungs and histological staining results further indicated severe tissue injury and inflammatory cell infiltration in copper-exposed rats. To this side, treatment with melatonin showed antioxidant and anti-inflammatory activities evidenced by reduced oxidative stress, tissue inflammation and collagen deposition as compared to copper-exposed animals. Moreover, spectral findings suggested melatonin treatment modulated the frequency sift, as compared to copper-challenged animals. Altogether, the present results suggest that melatonin might play a potential role in preventing copper-induced lung aberrations via inhibiting the ROS-mediated oxidative stress and inflammation.

Protective effects of silibinin on LPS-induced inflammation in human periodontal ligament cells

Clinically, periodontitis is a chronic nonspecific inflammation that leads to damaged teeth and their supporting gum tissues. Although many studies on periodontitis have been conducted, therapy with natural products is still rare. Silibinin has been proven to have anti-inflammatory and antioxidant activities. However, the effects of silibinin on lipopolyssacharide (LPS)-induced inflammation in periodontal ligaments (PDLs) have not yet been investigated. In this study, the PDLs were treated with silibinin (10, 20, and 40 μM) in the presence of LPS. The results showed that silibinin treatment reduced the levels of NO, PGE2, IL-6, TNF-α, MMP-1, and MMP-3 and enhanced the activities of superoxide dismutase (SOD) and glutathione (GSH). Moreover, silibinin treatment downregulated RANKL levels and upregulated OPG and ALP levels. In summary, silibinin protected PDLs against LPS-induced inflammation, oxidative stress, and osteogenic differentiation.

Combined Silymarin and Cotrimoxazole Therapy Attenuates Pulmonary Fibrosis in Experimental Paracoccidioidomycosis

Paracoccidioidomycosis (PCM), which mainly affects rural workers, is a systemic mycosis caused by the Paracoccidioides genus that induces pulmonary sequelae in most adult patients, causing serious disability and impairing their quality of life. Silymarin is herbal medicine with an effective antifibrotic activity. Considering that in PCM, antifibrotic treatment is still not available in pulmonary fibrosis, we aimed to evaluate combined silymarin and cotrimoxazole (CMX) therapy via the intratracheal route in BALB/c mice infected with P. brasiliensis yeast. After 12 weeks of treatment, the lungs were collected for the determination of fungal burden, production of OH-proline, deposition of collagen fibers, pulmonary concentrations of cytokines, and expression of fibronectin, α-SMA, MMP-2, MMP-9, and TIMP-2. Spleen cell cultures were also performed. Our results showed that infected mice treated with combined silymarin/CMX showed lower deposition of collagen fibers in the lungs and lower pulmonary concentrations of hydroxyproline than the placebo groups. Decreased levels of TGF-β1 and fibronectin and high levels of MMP-2 and IFN-γ were also observed in this group of mice. Collectively, our findings indicate that the combination of antifungal treatment with silymarin has a potent antifibrotic effect associated with an immunomodulatory effect that potentializes the antifungal immune response.