Metformin alleviates crystalline silica-induced pulmonary fibrosis by remodeling endothelial cells to mesenchymal transition via autophagy signaling

Exosomes derived from adipose tissue-derived stem cells alleviated H2O2-induced oxidative stress and endothelial-to-mesenchymal transition in human umbilical vein endothelial cells by inhibition of the mir-486-3p/Sirt6/Smad signaling pathway

Hypertrophic scar (HS) is characterized by excessive collagen deposition and myofibroblasts activation. Endothelial-to-mesenchymal transition (EndoMT) and oxidative stress were pivotal in skin fibrosis process. Exosomes derived from adipose tissue-derived stem cells (ADSC-Exo) have the potential to attenuate EndoMT and inhibit fibrosis. The study revealed reactive oxygen species (ROS) levels were increased during EndoMT occurrence of dermal vasculature of HS. The morphology of endothelial cells exposure to H2O2, serving as an in vitro model of oxidative stress damage, transitioned from a cobblestone-like appearance to a spindle-like shape. Additionally, the levels of endothelial markers decreased in H2O2-treated endothelial cell, while the expression of fibrotic markers increased. Furthermore, H2O2 facilitated the accumulation of ROS, inhibited cell proliferation, retarded its migration and suppressed tube formation in endothelial cell. However, ADSC-Exo counteracted the biological effects induced by H2O2. Subsequently, miRNAs sequencing analysis revealed the significance of mir-486-3p in endothelial cell exposed to H2O2 and ADSC-Exo. Mir-486-3p overexpression enhanced the acceleration of EndoMT, its inhibitors represented the attenuation of EndoMT. Meanwhile, the target regulatory relationship was observed between mir-486-3p and Sirt6, whereby Sirt6 exerted its anti-EndoMT effect through Smad2/3 signaling pathway. Besides, our research had successfully demonstrated the impact of ADSC-Exo and mir-486-3p on animal models. These findings of our study collectively elucidated that ADSC-Exo effectively alleviated H2O2-induced ROS and EndoMT by inhibiting the mir-486-3p/Sirt6/Smad axis.

Vinpocetine alleviated alveolar epithelial cells injury in experimental pulmonary fibrosis by targeting PPAR-γ/NLRP3/NF-κB and TGF-β1/Smad2/3 pathways

This study aimed to investigate the potential anti-fibrotic activity of vinpocetine in an experimental model of pulmonary fibrosis by bleomycin and in the MRC-5 cell line. Pulmonary fibrosis was induced in BALB/c mice by oropharyngeal aspiration of a single dose of bleomycin (5 mg/kg). The remaining induced animals received a daily dose of pirfenidone (as a standard anti-fibrotic drug) (300 mg/kg/PO) and vinpocetine (20 mg/kg/PO) on day 7 of the induction till the end of the experiment (day 21). The results of the experiment revealed that vinpocetine managed to alleviate the fibrotic endpoints by statistically improving (P ≤ 0.05) the weight index, histopathological score, reduced expression of fibrotic-related proteins in immune-stained lung sections, as well as fibrotic markers measured in serum samples. It also alleviated tissue levels of oxidative stress and inflammatory and pro-fibrotic mediators significantly elevated in bleomycin-only induced animals (P ≤ 0.05). Vinpocetine managed to express a remarkable attenuating effect in pulmonary fibrosis both in vivo and in vitro either directly by interfering with the classical TGF-β1/Smad2/3 signaling pathway or indirectly by upregulating the expression of Nrf2 enhancing the antioxidant system, activating PPAR-γ and downregulating the NLRP3/NF-κB pathway making it a candidate for further clinical investigation in cases of pulmonary fibrosis.

Emerging application of nanomedicine-based therapy in acute respiratory distress syndrome

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are serious lung injuries caused by various factors, leading to increased permeability of the alveolar-capillary barrier, reduced stability of the alveoli, inflammatory response, and hypoxemia. Despite several decades of research since ARDS was first formally described in 1967, reliable clinical treatment options are still lacking. Currently, supportive therapy and mechanical ventilation are prioritized, and there is no medication that can be completely effective in clinical treatment. In recent years, nanomedicine has developed rapidly and has exciting preclinical treatment capabilities. Using a drug delivery system based on nanobiotechnology, local drugs can be continuously released in lung tissue at therapeutic levels, reducing the frequency of administration and improving patient compliance. Furthermore, this novel drug delivery system can target specific sites and reduce systemic side effects. Currently, many nanomedicine treatment options for ARDS have demonstrated efficacy. This review briefly introduces the pathophysiology of ARDS, discusses various research progress on using nanomedicine to treat ARDS, and anticipates future developments in related fields.

Tectorigenin protects against cardiac fibrosis in diabetic mice heart via activating the adiponectin receptor 1-mediated AMPK pathway

Diabetic cardiomyopathy (DCM) is a common severe complication of diabetes that occurs independently of hypertension, coronary artery disease, and valvular cardiomyopathy, eventually leading to heart failure. Previous studies have reported that Tectorigenin (TEC) possesses extensive anti-inflammatory and anti-oxidative stress properties. In this present study, the impact of TEC on diabetic cardiomyopathy was examined. The model of DCM in mice was established with the combination of a high-fat diet and STZ treatment. Remarkably, TEC treatment significantly attenuated cardiac fibrosis and improved cardiac dysfunction. Concurrently, TEC was also found to mitigate hyperglycemia and hyperlipidemia in the DCM mouse. At the molecular level, TEC is involved in the activation of AMPK, both in vitro and in vivo, by enhancing its phosphorylation. This is achieved through the regulation of endothelial-mesenchymal transition via the AMPK/TGFβ/Smad3 pathway. Furthermore, it was demonstrated that the level of ubiquitination of the adiponectin receptor 1 (AdipoR1) protein is associated with TEC-mediated improvement of cardiac dysfunction in DCM mice. Notably the substantial reduction of myocardial fibrosis. In conclusion, TEC improves cardiac fibrosis in DCM mice by modulating the AdipoR1/AMPK signaling pathway. These findings suggest that TEC could be an effective therapeutic agent for the treatment of diabetic cardiomyopathy.

Xue-jie-San prevents the early development of colitis-associated intestinal fibrosis by blocking Notch1 and FGL1 signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Xue-Jie-San (XJS), as a traditional Chinese herb prescription, has satisfactory effects on improving clinical symptoms and facilitating the healing of intestinal ulcers in patients with Crohn's disease (CD). This motivates the application of XJS on CD-associated complications.

AIM OF THE STUDY

Intestinal fibrosis is a debilitating complication of CD. Currently, there is no effective medication available for preventing or reversing CD-related intestinal fibrosis. This study aimed to assess the efficacy and underlying mechanisms of XJS in the treatment of colitis-associated intestinal fibrosis.

MATERIALS AND METHODS

A rat model of CD-related intestinal fibrosis was induced by 2,4,6-trinitrobenzene sulfonic acid administration and treated with XJS. The pathological changes of intestinal fibrosis were evaluated using Masson staining. Collagen deposition and epithelial-to-mesenchymal transition (EMT) were verified by immunohistochemical staining and western blot analysis. Endothelial-to-mesenchymal transition (EndoMT) was assessed with immunofluorescence and immunohistochemical staining as well as western blot analysis. Transmission electron microscopy was utilized to observe autophagosomes. The levels of autophagy-related proteins were detected via immunofluorescence staining and western blot. Finally, the mTOR/ULK1 signaling pathway regulated by Notch1 or FGL1 was analyzed by western blot.

RESULTS

The results found that XJS ameliorated intestinal fibrosis through reducing the deposition of collagens such as Collagen 1 and Collagen 3. XJS inhibited the EMT process by increasing E-cadherin levels and decreasing the expressions of N-cadherin, Vimentin and Snail, which played a crucial role in collagen secretion and intestinal fibrosis. In addition, XJS also repressed the EndoMT process as reflected by the upregulation of CD31 and VE-cadherin levels and the downregulation of FSP1 and α-SMA expressions. Autophagy was activated following XJS treatment via suppression of the mTOR/ULK1 signaling pathway. Furthermore, XJS acted as an inhibitor of Notch1 and FGL1 signals, both of which regulated the mTOR signaling.

CONCLUSIONS

Our findings validated that XJS prevented the early development of CD-related intestinal fibrosis by blocking the Notch1 and FGL1 signaling pathways to activate autophagy and thereby inhibit EMT and EndoMT.

Activation of AMPK signalling by Metformin: Implication an important molecular mechanism for protecting against mice silicosis via inhibited endothelial cell-to-mesenchymal transition by regulating oxidative stress and apoptosis

Inhalation of silica particles (SiO₂) causes oxidative stress-induced inflammation and cell apoptosis, ultimately resulting in irreversible pulmonary fibrosis, Unfortunately, effective treatment or preventative measures have yet to be fully established. Metformin (Met), a relatively safe and effective medication for treating diabetes, may hold promise as protective agent against early-stage pulmonary fibrosis in mice through the activation of autophagy and inhibition of endothelial cell to mesenchymal transition (EndoMT). Here, we investigated whether Met could reduce silicosis in mice by regulating inflammation, oxidative stress, and apoptosis, and to identify the underlying protective effect on endothelial cells. First, through pathological observation, we found that 21 consecutive days of Met (100 mg/kg) administration is optimal against silicosis. Next, using haematoxylin-eosin and Masson's trichrome staining and immunoblotting, we found that Met effectively blunted the inflammatory response and collagen deposition at 56 days after exposure to SiO₂. We also demonstrated that Met effectively activates AMPK signalling and markedly relieves oxidative stress, the mitochondrial apoptotic pathway and EndoMT induced by SiO₂ exposure both in vivo and in vitro. Overall, Met can alleviate SiO₂-induced pulmonary fibrosis by regulating oxidative stress and the mitochondrial apoptotic pathway. The current study provides a rationale for the clinical treatment of SiO₂-induced pulmonary fibrosis.

Atractylenolide III Ameliorated Autophagy Dysfunction via Epidermal Growth Factor Receptor-Mammalian Target of Rapamycin Signals and Alleviated Silicosis Fibrosis in Mice

Atractylenolide III (ATL-III) is a major active constituent of the natural plant Atractylodes rhizome. Our previous study has shown that ATL-III may alleviate alveolar macrophage apoptosis via the inhibition of the mammalian target of rapamycin (mTOR)-mediated autophagy of human silicosis. Therefore, we aimed to further explore the function of ATL-III in autophagy, apoptosis, and pulmonary fibrosis by establishing the ATL-III-intervened silicosis mouse model in this study. Meanwhile, we sought and then verified potential autophagy-related signaling pathways by matching differentially expressed genes (attained by RNA sequencing) and the autophagy database. In this study, RNA-sequencing results implied that the epidermal growth factor receptor, the crucial upstream activator of mTOR, was seen as a potential autophagy-regulatory molecule in the ATL-III-intervened silicosis mouse model. The finding of this study was that ATL-III might improve the disorder of autophagic degradation via the activation of epidermal growth factor receptor-mTOR signals in the pulmonary tissue of the silicosis mouse model. ATL-III also alleviated cell apoptosis and silicotic fibrosis. Overall, we supposed that ATL-III might be a potential protective medicine, which had a regulatory effect on autophagy, for the intervention of silicotic fibrosis. In the future, the therapeutic drugs for silicosis should be further focused on the development and application of such natural autophagy agents.

Pulmonary Fibrosis as a Result of Acute Lung Inflammation: Molecular Mechanisms, Relevant In Vivo Models, Prognostic and Therapeutic Approaches

Pulmonary fibrosis is a chronic progressive lung disease that steadily leads to lung architecture disruption and respiratory failure. The development of pulmonary fibrosis is mostly the result of previous acute lung inflammation, caused by a wide variety of etiological factors, not resolved over time and causing the deposition of fibrotic tissue in the lungs. Despite a long history of study and good coverage of the problem in the scientific literature, the effective therapeutic approaches for pulmonary fibrosis treatment are currently lacking. Thus, the study of the molecular mechanisms underlying the transition from acute lung inflammation to pulmonary fibrosis, and the search for new molecular markers and promising therapeutic targets to prevent pulmonary fibrosis development, remain highly relevant tasks. This review focuses on the etiology, pathogenesis, morphological characteristics and outcomes of acute lung inflammation as a precursor of pulmonary fibrosis; the pathomorphological changes in the lungs during fibrosis development; the known molecular mechanisms and key players of the signaling pathways mediating acute lung inflammation and pulmonary fibrosis, as well as the characteristics of the most common in vivo models of these processes. Moreover, the prognostic markers of acute lung injury severity and pulmonary fibrosis development as well as approved and potential therapeutic approaches suppressing the transition from acute lung inflammation to fibrosis are discussed.