M10 peptide attenuates silica-induced pulmonary fibrosis by inhibiting Smad2 phosphorylation

Emerging delivery approaches for targeted pulmonary fibrosis treatment

Pulmonary fibrosis (PF) is a progressive, and life-threatening interstitial lung disease which causes scarring in the lung parenchyma and thereby affects architecture and functioning of lung. It is an irreversible damage to lung functioning which is related to epithelial cell injury, immense accumulation of immune cells and inflammatory cytokines, and irregular recruitment of extracellular matrix. The inflammatory cytokines trigger the differentiation of fibroblasts into activated fibroblasts, also known as myofibroblasts, which further increase the production and deposition of collagen at the injury sites in the lung. Despite the significant morbidity and mortality associated with PF, there is no available treatment that efficiently and effectively treats the disease by reversing their underlying pathologies. In recent years, many therapeutic regimens, for instance, rho kinase inhibitors, Smad signaling pathway inhibitors, p38, BCL-xL/ BCL-2 and JNK pathway inhibitors, have been found to be potent and effective in treating PF, in preclinical stages. However, due to non-selectivity and non-specificity, the therapeutic molecules also result in toxicity mediated severe side effects. Hence, this review demonstrates recent advances on PF pathology, mechanism and targets related to PF, development of various drug delivery systems based on small molecules, RNAs, oligonucleotides, peptides, antibodies, exosomes, and stem cells for the treatment of PF and the progress of various therapeutic treatments in clinical trials to advance PF treatment.

Emergent Peptides of the Antifibrotic Arsenal: Taking Aim at Myofibroblast Promoting Pathways

Myofibroblasts are the principal effector cells driving fibrosis, and their accumulation in tissues is a fundamental feature of fibrosis. Essential pathways have been identified as being central to promoting myofibroblast differentiation, revealing multiple targets for intervention. Compared with large proteins and antibodies, peptide-based therapies have transpired to serve as biocompatible and cost-effective solutions to exert biomimicry, agonistic, and antagonistic activities with a high degree of targeting specificity and selectivity. In this review, we summarize emergent antifibrotic peptides and their utilization for the targeted prevention of myofibroblasts. We then highlight recent studies on peptide inhibitors of upstream pathogenic processes that drive the formation of profibrotic cell phenotypes. We also briefly discuss peptides from non-mammalian origins that show promise as antifibrotic therapeutics. Finally, we discuss the future perspectives of peptide design and development in targeting myofibroblasts to mitigate fibrosis.

Therapeutic Peptides for Treatment of Lung Diseases: Infection, Fibrosis, and Cancer

Various lung diseases endanger people's health. Side effects and pharmaceutical resistance complicate the treatment of acute lung injury, pulmonary fibrosis, and lung cancer, necessitating the development of novel treatments. Antimicrobial peptides (AMPs) are considered to serve as a viable alternative to conventional antibiotics. These peptides exhibit a broad antibacterial activity spectrum as well as immunomodulatory properties. Previous studies have shown that therapeutic peptides including AMPs had remarkable impacts on animal and cell models of acute lung injury, pulmonary fibrosis, and lung cancer. The purpose of this paper is to outline the potential curative effects and mechanisms of peptides in the three types of lung diseases mentioned above, which may be used as a therapeutic strategy in the future.

Peptide mediated therapy in fibrosis: Mechanisms, advances and prospects

Fibrosis, a disease characterized by an excess accumulation of extracellular matrix components, could lead to organ failure and death, and is to blame for up to 45 % of all fatalities in developed nations. These disorders all share the common trait of an unchecked and increasing accumulation of fibrotic tissue in the affected organs, which leads to their malfunction and eventual failure, even if their underlying causes are highly diverse and, in some cases, remain unclear. Numerous studies have identified activated myofibroblasts as the common cellular elements ultimately responsible for the replacement of normal tissues with nonfunctional fibrotic tissue. The transforming growth factor-β pathway, for instance, plays a significant role in practically all kinds of fibrosis. However, there is no specific drug for the treatment of fibrosis, several medications with anti-hepatic fibrosis properties are still in the research and development stages. Peptide, which refers to a substance consisting of 2-50 amino acids, is characterized by structural diversity, low toxicity, biological activities, easy absorption, specific targeting, few side effects, and has been proven to be effective in anti-fibrosis. Here, we summarized various anti-fibrosis peptides in fibrosis including the liver, lungs, kidneys, and other organs. This review will provide a new insight into peptide mediated anti-fibrosis and is helpful to creation of antifibrotic medications.

Effect of Pheretima aspergillum on reducing fibrosis: A systematic review and meta-analysis

Background: Pheretima aspergillum (common name: Earthworm, Chinese name: dilong) has been used in traditional Chinese medicine for thousands of years. Recently, a few scientific studies have investigated the antifibrotic effects of Dilong extract (DE) and produced controversial results. We conducted a meta-analysis to make an informed decision on the antifibrotic effects of Dilong extract. Methods: The studies on antifibrotic effects of Dilong extract published until July 2022 in the scientific databases [PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), VIP database for Chinese Technical Periodicals, SinoMed and WanFang database] were reviewed. The RevMan 5.4.1 software was used for standardized mean difference (SMD) analysis. Two researchers independently reviewed all the studies, and their quality was assessed using the Cochrane risk of bias tool. Results: A total of 325 studies were found in the scientific databases; however, only 13 studies met the criteria for analysis. Dilong extract treatment was associated with antifibrotic effects via inhibiting the transforming growth factor beta 1 (TGF-β1, SMD = -3.16, 95% CI: -4.18, -2.14, p < .00001) and alpha-smooth muscle actin (α-SMA: SMD = -2.57, 95% CI: -3.47, -1.66, p < .00001). Conclusion: Dilong extract effectively reduces tissue fibrosis; thus, further scientific studies should be conducted to investigate and develop it for clinical use. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42022357141.

Metformin attenuates silica-induced pulmonary fibrosis via AMPK signaling

Background

Silicosis is one of the most common occupational pulmonary fibrosis caused by respirable silica-based particle exposure, with no ideal drugs at present. Metformin, a commonly used biguanide antidiabetic agent, could activate AMP-activated protein kinase (AMPK) to exert its pharmacological action. Therefore, we sought to investigate the role of metformin in silica-induced lung fibrosis.

Methods

The anti-fibrotic role of metformin was assessed in 50 mg/kg silica-induced lung fibrosis model. Silicon dioxide (SiO₂)-stimulated lung epithelial cells/macrophages and transforming growth factor-beta 1 (TGF-β1)-induced differentiated lung fibroblasts were used for in vitro models.

Results

At the concentration of 300 mg/kg in the mouse model, metformin significantly reduced lung inflammation and fibrosis in SiO₂-instilled mice at the early and late fibrotic stages. Besides, metformin (range 2–10 mM) reversed SiO₂-induced cell toxicity, oxidative stress, and epithelial-mesenchymal transition process in epithelial cells (A549 and HBE), inhibited inflammation response in macrophages (THP-1), and alleviated TGF-β1-stimulated fibroblast activation in lung fibroblasts (MRC-5) via an AMPK-dependent pathway.

Conclusions

In this study, we identified that metformin might be a potential drug for silicosis treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03036-5.

LncRNA-PVT1 activates lung fibroblasts via miR-497-5p and is facilitated by FOXM1

It is little known about the lncRNA-PVT1 effect on occupational pulmonary fibrosis, although researches show it plays an essential role in cancer. Studies reveal that lung fibroblast activation is one of the key events in silica-induced fibrosis. Here, we found that lncRNA-PVT1 promoted the proliferation, activation, and migration of lung fibroblasts. The isolation of cytoplasmic and nuclear RNA assay and fluorescence in situ hybridization experiment showed that lncRNA-PVT1 was abundantly expressed in the cytoplasm. Luciferase reporter gene assay and RNA pull-down experiment indicated that the cytoplasmic-localized lncRNA-PVT1 could competitively bind miR-497-5p. MiR-497-5p was further observed to attenuate silica-induced pulmonary fibrosis by targeting Smad3 and Bcl2. Moreover, the transcription factor FOXM1 acted as a profibrotic factor by elevating lncRNA-PVT1 transcription in lung fibroblasts. Inhibition of FOXM1 expression with thiostrepton alleviated silica-induced pulmonary fibrosis in vivo. Collectively, we revealed that FOXM1-facilitated lncRNA-PVT1 activates lung fibroblasts via miR-497-5p during silica-induced pulmonary fibrosis, which may provide potential therapeutic targets for pulmonary fibrosis.

MiR-503 suppresses fibroblast activation and myofibroblast differentiation by targeting VEGFA and FGFR1 in silica-induced pulmonary fibrosis

Inhalation and deposition of crystalline silica particles in the lung can cause pulmonary fibrosis, then leading to silicosis. Given the paucity of effective drugs for silicosis, new insights for understanding the mechanisms of silicosis, including lung fibroblast activation and myofibroblast differentiation, are essential to explore therapeutic strategies. Our previous research showed that the up-regulation of miR-503 alleviated silica-induced pulmonary fibrosis in mice. In this study, we investigated whether miR-503 can regulate the TGF-β1-induced effects in lung fibroblasts. Mimic-based strategies aiming at up-regulating miR-503 were used to discuss the function of miR-503 in vivo and in vitro. We found that the expression level of miR-503 was decreased in fibroblasts stimulated by TGF-β1, and the up-regulation of miR-503 reduced the release of fibrotic factors and inhibited the migration and invasion abilities of fibroblasts. Combined with the up-regulation of miR-503 in a mouse model of silica-induced pulmonary fibrosis, we revealed that miR-503 mitigated the TGF-β1-induced effects in fibroblasts by regulating VEGFA and FGFR1 and then affecting the MAPK/ERK signalling pathway. In conclusion, miR-503 exerted protective roles in silica-induced pulmonary fibrosis and may represent a novel and potent candidate for therapeutic strategies in silicosis.