Synthesis and discovery of a drug candidate for treatment of idiopathic pulmonary fibrosis through inhibition of TGF-β1 pathway

Searching for Novel Candidate Small Molecules for Ameliorating Idiopathic Pulmonary Fibrosis: a Narrative Review

Idiopathic pulmonary fibrosis (IPF) can be defined as a progressive chronic pulmonary disease showing scarring in the lung parenchyma, thereby resulting in increase in mortality and decrease in the quality of life. The pathophysiologic mechanism of fibrosis in IPF is still unclear. Repetitive microinjuries to alveolar epithelium with genetical predisposition and an abnormal restorative reaction accompanied by excessive deposition of collagens are involved in the pathogenesis. Although the two FDA-approved drugs, pirfenidone and nintedanib, are under use for retarding the decline in lung function of patients suffered from IPF, they are not able to improve the survival rate or quality of life. Therefore, a novel therapeutic agent acting on the major steps of the pathogenesis of disease and/or, at least, managing the clinical symptoms of IPF should be developed for the effective regulation of this incurable disease. In the present review, we tried to find a potential of managing the clinical symptoms of IPF by natural products derived from medicinal plants used for controlling the pulmonary inflammatory diseases in traditional Asian medicine. A multitude of natural products have been reported to exert an antifibrotic effect in vitro and in vivo through acting on the epithelial-mesenchymal transition pathway, transforming growth factor (TGF)-β-induced intracellular signaling, and the deposition of extracellular matrix. However, clinical antifibrotic efficacy of these natural products on IPF have not been elucidated yet. Thus, those effects should be proven by further examinations including the randomized clinical trials, in order to develop the ideal and optimal candidate for the therapeutics of IPF.

Natural Product-Based Potential Therapeutic Interventions of Pulmonary Fibrosis

Pulmonary fibrosis (PF) is a disease-refractive lung condition with an increased rate of mortality. The potential factors causing PF include viral infections, radiation exposure, and toxic airborne chemicals. Idiopathic PF (IPF) is related to pneumonia affecting the elderly and is characterized by recurring scar formation in the lungs. An impaired wound healing process, defined by the dysregulated aggregation of extracellular matrix components, triggers fibrotic scar formation in the lungs. The potential pathogenesis includes oxidative stress, altered cell signaling, inflammation, etc. Nintedanib and pirfenidone have been approved with a conditional endorsement for the management of IPF. In addition, natural product-based treatment strategies have shown promising results in treating PF. In this study, we reviewed the recently published literature and discussed the potential uses of natural products, classified into three types-isolated active compounds, crude extracts of plants, and traditional medicine, consisting of mixtures of different plant products-in treating PF. These natural products are promising in the treatment of PF via inhibiting inflammation, oxidative stress, and endothelial mesenchymal transition, as well as affecting TGF-β-mediated cell signaling, etc. Based on the current review, we have revealed the signaling mechanisms of PF pathogenesis and the potential opportunities offered by natural product-based medicine in treating PF.

A Novel Anticancer Stem Cell Compound Derived from Pleuromutilin Induced Necroptosis of Melanoma Cells

Necroptosis has been recently confirmed as a non-apoptotic form of programmed cell death. Discovery of novel chemical entities, capable of inducing necroptosis of cancer cells, is likely to act as an alternative strategy for dealing with drug resistance clinically. In this study, the identification of a novel Pleuromutilin derivative (compound 38) is presented, capable of significantly increasing the cellular level of ROS and inducing melanoma cancer cell death via necroptosis. Furthermore, compound 38 noticeably ablated various cancer stem cells and inhibited the growth of melanoma cancer cells both in vitro and in vivo. Moreover, 38 exhibited low toxicity in animal models and excellent PK properties, which is currently being verified as a potential anticancer drug candidate.

Regulation of transforming growth factor-β signalling by SUMOylation and its role in fibrosis

Fibrosis is an abnormal healing process that only repairs the structure of an organ after injury and does not address damaged functions. The pathogenesis of fibrosis is multifactorial and highly complex; numerous signalling pathways are involved in this process, with the transforming growth factor-β (TGF-β) signalling pathway playing a central role. TGF-β regulates the generation of myofibroblasts and the epithelial-mesenchymal transition by regulating transcription and translation of downstream genes and precisely regulating fibrogenesis. The TGF-β signalling pathway can be modulated by various post-translational modifications, of which SUMOylation has been shown to play a key role. In this review, we focus on the function of SUMOylation in canonical and non-canonical TGF-β signalling and its role in fibrosis, providing promising therapeutic strategies for fibrosis.

Alantolactone: A sesquiterpene lactone with diverse pharmacological effects

Alantolactone (Ala) is a sesquiterpene lactone that can be isolated from many herbal plants belonging to Asteraceae. Besides the antimicrobial activities against bacteria, fungi and viruses, Ala has also demonstrated significant anti-inflammatory effects in various models by inhibiting NF-κB and MAPKs to decrease the pro-inflammatory cytokines such as IL-1β, IL-6 and TNF-α. The antitumor effects of Ala have been demonstrated in vitro and in vivo via inducing intrinsic apoptosis, oxidative stress, ER stress, cell cycle arrest and inhibiting autophagy and STAT3 phosphorylation, which are also involved in its combination or synergy with other antitumor drugs. Ala also has neuroprotective activity through attenuating oxidative stress and inflammation, besides its modulation of glucose and lipid metabolism. This review summarizes the recent advances of the pharmacological effects of Ala, including anti-inflammatory, antitumor, antimicrobial, neuroprotective activities, as well as the underlying mechanisms. Ala might be employed as a potential lead to develop drugs for multiple diseases.

Isoalantolactone alleviates ovalbumin‑induced asthmatic inflammation by reducing alternatively activated macrophage and STAT6/PPAR‑γ/KLF4 signals

Isoalantolactone (IAL), a sesquiterpene lactone, has anti‑inflammatory activity in lipopolysaccharide (LPS)‑induced sepsis. However, it remains to be elucidated whether IAL influences asthmatic inflammation. The present study found that IAL inhibited ovalbumin (OVA)‑induced asthmatic inflammation and attenuated OVA‑induced eosinophil infiltration, immunoglobulin E generation and the production of interleukin (IL)‑4, IL‑5, C‑C motif chemokine ligand (CCL)17 and CCL22. In addition, IAL treatment with IL‑4 reduced the expression of arginase‑1, Ym‑1, CCL17 and CCL22 in bone marrow‑derived macrophages in vitro. Furthermore, IAL inhibited IL‑4‑induced STAT6 phosphorylation and the expression of peroxisome proliferator‑activated receptor γ and Krüppel‑like factor 4. Collectively, the results suggested that IAL attenuated asthmatic inflammation and is a potential therapeutic agent for the treatment of asthma.

5α-Epoxyalantolactone Inhibits Metastasis of Triple-Negative Breast Cancer Cells by Covalently Binding a Conserved Cysteine of Annexin A2

Triple-negative breast cancer (TNBC) has been considered the most aggressive and mortal breast cancer. Thus far, it remains an important challenge to develop TNBC targeted therapy. As revealed from numerous recent studies, ANXA2 may be a potential target to treat TNBC. In the present study, a natural product 5α-epoxyalantolactone (5α-EAL) was discovered as an anti-breast cancer stem cells (BCSCs) lead compound. Furthermore, 5α-EAL was found to be able to notably suppress the function of ANXA2 by covalently targeting cysteine 9 (Cys9) of ANXA2. To the best of our knowledge, 5α-EAL was recognized as the first small molecule functional inhibitor of ANXA2. It could significantly inhibit the formation of the heterotetrameric complex of ANXA2 and S100A10, which is capable of transporting E-cadherin (E-Ca) to the membrane. The above findings may be used as a possible strategy to develop novel anti-TNBC therapies targeting ANXA2.

Potential Mechanism Prediction of Herbal Medicine for Pulmonary Fibrosis Associated with SARS-CoV-2 Infection Based on Network Analysis and Molecular Docking

Background: Coronavirus Disease 2019 (COVID-19) is still a relevant global problem. Although some patients have recovered from COVID-19, the sequalae to the SARS-CoV-2 infection may include pulmonary fibrosis, which may contribute to considerable economic burden and health-care challenges. Convalescent Chinese Prescription (CCP) has been widely used during the COVID-19 recovery period for patients who were at high risk of pulmonary fibrosis and is recommended by the Diagnosis and Treatment Protocol for COVID-19 (Trial Version sixth, seventh). However, its underlying mechanism is still unclear. Methods: In this study, an integrated pharmacology approach was implemented, which involved evaluation of absorption, distribution, metabolism and excretion of CCP, data mining of the disease targets, protein-protein interaction (PPI) network construction, and analysis, enrichment analysis, and molecular docking simulation, to predict the bioactive components, potential targets, and molecular mechanism of CCP for pulmonary fibrosis associated with SARS-CoV-2 infection. Results: The active compound of CCP and the candidate targets, including pulmonary fibrosis targets, were obtained through database mining. The Drug-Disease network was constructed. Sixty-five key targets were identified by topological analysis. The findings of Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation suggested that the VEGF, Toll-like 4 receptor, MAPK signaling pathway, and TGF-β1 signaling pathways may be involved in pulmonary fibrosis. In the molecular docking analyses, VEGF, TNF-α, IL-6, MMP9 exhibited good binding activity. Findings from our study indicated that CCP could inhibit the expression of VEGF, TNF-α, IL-6, MMP9, TGF-β1 via the VEGF, Toll-like 4 receptor, MAPK, and TGF-β1 signaling pathways. Conclusion: Potential mechanisms involved in CCP treatment for COVID-19 pulmonary fibrosis associated with SARS-CoV-2 infection involves multiple components and multiple target points as well as multiple pathways. These findings may offer a profile for further investigations of the anti-fibrotic mechanism of CCP.

A comprehensive review of anticancer mechanisms of action of Alantolactone

Cancer is considered as the main challenge of human communities, and it annually imposes a significant economic burden on society. Natural products have been used for treatment of many diseases including inflammation, infections, neurological disorders, atherosclerosis, asthma and cancer for many years. Sesquiterpene lactones (STLs) refers to a group of natural products with different biological activities. A type of STL that has recently attracted much attention is Alantolactone (ALT). In recent years, many studies have investigated the molecular mechanism of this compound affecting cancer cells and results suggest that this compound exerts its anticancer effects by providing free radicals and inhibiting some of the signaling pathways that are effective in progression of cancer cells. The present study is aimed to introduce the latest molecular mechanisms of ALT proposed by researchers in recent years.

CRLF1 Is a Key Regulator in the Ligamentum Flavum Hypertrophy

Hypertrophy of the ligamentum flavum (HLF) is one of the common causes of lumbar spinal stenosis (LSS). The key molecules and mechanisms responsible for HLF remain unclear. Here, we used an integrated transcriptome and proteomics analysis of human ligamentum flavum (LF), and subsequent immunohistochemistry and real-time PCR assays, to show upregulation of CRLF1 to be the dominant response to HLF. TGF-β1 significantly increased mRNA expression of CRLF1 through SMAD3 pathway. CRLF1 enhanced LF fibrosis via ERK signaling pathway at the post-transcriptional level and was required for the pro-fibrotic effect of TGF-β1. Knockdown of CRLF1 was shown here to reduce fibrosis caused by inflammatory cytokines and mechanical stress. Furthermore, we found that bipedal standing posture can cause HLF and upregulation of CRLF1 expression in mice LF. Overexpression of CRLF1 was indicated to cause HLF in vivo, whereas CRLF1 knockdown impeded the formation of HLF in bipedal standing mice. These results revealed a crucial role of CRLF1 in LF hypertrophy. We propose that inhibition of CRLF1 is a potential therapeutic strategy to treat HLF.

Isoalantolactone inhibits RANKL-induced osteoclast formation via multiple signaling pathways

The metabolicosteopathy known as postmenopausal osteoporosisiscaused by disruption of the balance between bone resorption and osteogenesis, processes that are mediated by osteoclasts and osteoblasts, respectively. The current therapeutic approaches to treating osteoporosis have several limitations. In this study, we demonstrated that the natural chemical compound isoalantolactone (IAL) could inhibit osteoclastogenesis, without affecting osteogenesis. This is the first study reporting a role of IAL in suppressing the receptor activator of nuclear factor-kappa B ligand (RANKL)-induced osteoclast formation in a dose-dependent manner, and downregulating the expression of osteoclast-related marker genes. Furthermore, IAL abrogated the phosphorylation of c-Jun N-terminal kinase (JNK)/p38, NF-κB, and phosphatidylinositol 3-kinase (PI3K)-AKT, and also diminished the expression of osteoclastogenesis-related proteins. In conclusion, our results indicated that IAL has promise for the treatment of osteoporosis and other metabolicbone diseases.

Applications of Sesquiterpene Lactones: A Review of Some Potential Success Cases

Sesquiterpene lactones, a vast range of terpenoids isolated from Asteraceae species, exhibit a broad spectrum of biological effects and several of them are already commercially available, such as artemisinin. Here the most recent and impactful results of in vivo, preclinical and clinical studies involving a selection of ten sesquiterpene lactones (alantolactone, arglabin, costunolide, cynaropicrin, helenalin, inuviscolide, lactucin, parthenolide, thapsigargin and tomentosin) are presented and discussed, along with some of their derivatives. In the authors’ opinion, these compounds have been neglected compared to others, although they could be of great use in developing important new pharmaceutical products. The selected sesquiterpenes show promising anticancer and anti-inflammatory effects, acting on various targets. Moreover, they exhibit antifungal, anxiolytic, analgesic, and antitrypanosomal activities. Several studies discussed here clearly show the potential that some of them have in combination therapy, as sensitizing agents to facilitate and enhance the action of drugs in clinical use. The derivatives show greater pharmacological value since they have better pharmacokinetics, stability, potency, and/or selectivity. All these natural terpenoids and their derivatives exhibit properties that invite further research by the scientific community.

Design, synthesis and discovery of 2(1H)-quinolone derivatives for the treatment of pulmonary fibrosis through inhibition of TGF-β/smad dependent and independent pathway

Idiopathic pulmonary fibrosis (IPF) is a progressive, life-threatening and interstitial lung disease with the median survival of only 3-5 years. However, due to the unclear etiology and problems in accurate diagnosis, up to now only two drugs were approved by FDA for the treatment of IPF and their outcome responses are limited. Numerous studies have shown that TGF-β is the most important cytokine in the development of pulmonary fibrosis and plays a role through its downstream signaling molecule TGF-binding receptor Smads protein. In this paper, compounds bearing 2(1H)-quinolone scaffold were designed and their anti-fibrosis effects were evaluated. Of these compounds, 20f was identified as the most active one and could inhibit TGF-β-induced collagen deposition of NRK-49F cells and mouse fibroblasts migration with comparable activity and lower cytotoxicity than nintedanib in vitro. Further mechanism studies indicated that 20f reduced the expression of fibrogenic phenotypic protein α-SMA and collagen Ⅰ by inhibiting the TGF-β/Smad dependent pathways and ERK1/2 and p38 pathways. Moreover, compared with the nintedanib, 20f (100 mg/kg/day, p.o) more effectively alleviated collagen deposition in lung tissue and delayed the destruction of lung tissue structure both in bleomycin-induced prevention and treatment mice pulmonary fibrosis models. The immunohistochemical experiments further showed that 20f could block the expression level of phosphorylated Smad3 in the lung tissue cells, which resulted in its anti-fibrosis effects in vivo. In addition, 20f demonstrated good bioavailability (F = 41.55% vs 12%, compare with nintedanib) and an appropriate elimination half-life (T_1/2 = 3.5 h), suggesting that 20f may be a potential drug candidate for the treatment of pulmonary fibrosis.

New therapeutic strategies for IPF: Based on the "phagocytosis-secretion-immunization" network regulation mechanism of pulmonary macrophages

Pulmonary fibrosis is a chronic and progressive interstitial lung disease of known and unknown etiology. Over the past decades, macrophages have been recognized to play a significant role in IPF pathogenesis. According to their anatomical loci, macrophages can be divided to alveolar macrophages (AMs) subtypes and interstitial macrophages subtypes (IMs) with different responsibility in the damage defense response. Depending on diverse chemokines and cytokines in local microenvironments, macrophages can be induced and polarized to either classically activated (M1) or alternatively activated (M2) phenotypes in different stages of immunity. Therefore, we hypothesize that there is a "phagocytosis-secretion-immunization" network regulation of pulmonary macrophages related to a number of chemokines and cytokines. In this paper, we summarize and discuss the role of chemokines and cytokines involved in the "phagocytosis-secretion-immunization" network regulation mechanism of pulmonary macrophages, pointing toward novel therapeutic approaches based on the network target regulation in the field. Therapeutic strategies focused on modifying the chemokines, cytokines and the network are promising for the pharmacotherapy of IPF. Some Traditional Chinese medicines may have more superiorities in delaying the progression of pulmonary fibrosis for their multi-target activities of this network regulation.