Niclosamide alleviates pulmonary fibrosis in vitro and in vivo by attenuation of epithelial-to-mesenchymal transition, matrix proteins & Wnt/β-catenin signaling: A drug repurposing study

Niclosamide modulates phenotypic switch and inflammatory responses in human pulmonary arterial smooth muscle cells

Excessive proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs) represent key steps of pulmonary vascular remodeling, leading to the development of pulmonary arterial hypertension (PAH) and right ventricular failure. Niclosamide (NCL), an FDA-approved anthelmintic, has been shown to regulate cell proliferation, migration, invasion, and apoptosis through a variety of signaling pathways. However, its role on modulating the phenotypic switch and inflammatory responses in PASMCs remains unclear. In this study, cell proliferation assay showed that NCL inhibited PDGF-BB induced proliferation of human PASMCs in a dose-dependent manner. Western blot analysis further confirmed a notable reduction in the expression of cyclin D1 and PCNA proteins. Subsequently, flow cytometry analysis demonstrated that NCL induced an increased percentage of cells in the G1 phase while promoting apoptosis in PASMCs. Moreover, both scratch wound assay and transwell assay confirmed that NCL decreased PDGF-BB-induced migration of PASMCs. Mechanistically, western blot revealed that pretreatment of PASMCs with NCL markedly restored the protein levels of SMA, SM22, and calponin, while reducing phosphorylation of P38/STAT3 signaling in the presence of PDGF-BB. Interestingly, macrophages adhesion assay showed that NCL markedly reduced recruitment of Calcein-AM labeled RAW264.7 by TNFα-stimulated PASMCs. Western blot revealed that NCL suppressed TNFα-induced expression of both of VCAM-1 and ICAM-1 proteins. Furthermore, pretreatment of PASMCs with NCL significantly inhibited NLRP3 inflammasome activity through reducing NLRP3, AIM2, mature interleukin-1β (IL-β), and cleaved Caspase-1 proteins expression. Together, these results suggested versatile effects of NCL on controlling of proliferation, migration, and inflammatory responses in PASMCs through modulating different pathways, indicating that repurposing of NCL may emerge as a highly effective drug for PAH treatment.

Inhibition of peptidyl arginine deiminase-4 ameliorated pulmonary fibrosis via modulating M1/M2 polarisation of macrophages

Pulmonary fibrosis (PF) arises from dysregulated wound healing, leading to excessive extracellular matrix (ECM) deposition and impaired lung function. Macrophages exhibit high plasticity, polarizing to pro-inflammatory M1 during early inflammation and anti-inflammatory, fibrosis-inducing M2 during later stages of PF. Additionally, neutrophils and neutrophil extracellular traps (NETs) release mediated by peptidyl arginine deiminase (PAD-4), also play a key role in PF progression. PAD-4 inhibitor chloro-amidine (CLA) has shown anti-fibrotic effects in bleomycin (BLM) induced PF mouse model in our earlier study. Here, we have demonstrated that CLA also exhibited inhibition of macrophage polarisation in in-vitro in THP-1 monocytes and in-vivo in BLM induced PF. THP-1 monocytes were exposed to NETs isolated from phorbol 12-myristate-13-acetate (PMA) stimulated and PMA plus CLA treated differentiated HL-60 (dHL-60) cells. Monocytes exposed to stimulated NETs resulted in increased oxidative stress, disrupted mitochondrial membrane potential and increased M1 and M2 macrophage markers. These alterations were abrogated in THP-1 cells upon exposure to CLA treated NETs. Further, CLA treatment in BLM induced mice improved abnormal BALF, biochemical, and histological parameters in line with our previous findings. Additionally, CLA also reduced M1 and M2 markers time-dependently, as shown by immunofluorescence (IF), western blot, and RT-PCR analysis. CLA treatment led to decreased expression of PAD-4, M1-related pro-inflammatory cytokines and M2-related pro-fibrotic cytokines and mediators, as confirmed by western blot and ELISA analysis. Thus, it is established that inhibition of PAD-4 lead to mitigation of macrophage polarisation and a combined anti-fibrotic effect is achieved which can be explored further.

Niclosamide attenuates erectile dysfunction and corporal fibrosis via reversal of Smad signaling in diabetic rat model

BACKGROUND

Diabetes mellitus-induced erectile dysfunction (DMED) is a common urological complication of diabetes, and current drugs often fail to provide an effective treatment. Smad2/3 signaling-mediated corporal fibrosis has a critical role in the molecular basis of DMED.

AIM

We investigated the effect of Niclosamide (Nic), an antihelmintic drug with antifibrotic effects, on erectile function in a rat DMED model.

METHODS

Male Sprague Dawley rats were injected intraperitoneally (i.p) with streptozotocin (75 mg/kg) to induce diabetes. At week 8, both diabetic and nondiabetic rats were treated with Nic (10 mg·kg-1/day; i.p) or vehicle for 4 weeks. At week 12, erectile function was evaluated as intracavernous pressure (ICP) response to the electrical stimulation of the cavernous nerve (CN). Penile tissues were harvested for Masson's trichrome staining or western blotting to determine corporal fibrosis and Smad2/3 pathway-related protein expression, respectively.

OUTCOMES

At the end of the experimental protocol, in vivo erectile function was assessed by measuring the ratio of ICP/ mean arterial pressure (MAP) and total ICP following CN stimulation. Smooth muscle content and collagen fibers were evaluated by Masson's trichrome staining of the penile tissues. The expressions of fibrosis-related proteins (Smad2, Smad3, fibronectin) were determined using western blotting in the penile tissues.

RESULTS

Erectile function, as determined by the maximum ICP/MAP and total ICP/MAP ratios, was drastically decreased in diabetic rats. Corporal tissues of diabetic rats were severely fibrotic with a significant increase in collagen fibers and a marked reduction in smooth muscle content. Also, the protein expressions of phosphorylated (p-)Smad2, p-Smad3 and fibronectin were significantly increased in the penis of diabetic rats. Both functional and molecular alterations in DMED were effectively reversed by Nic-treated diabetic rats without a glycemic alteration.

CLINICAL IMPLICATIONS

Nic could be a promising candidate for the treatment of DMED due to its antifibrotic effects.

STRENGTHS AND LIMITATIONS

The present study provides the first evidence that Nic has beneficial effect on erectile dysfunction by attenuating corporal fibrosis in a rat model of DMED. The effect of Nic on penile endothelial function and the other potential underlying mechanisms needs to be further elucidated.

CONCLUSIONS

Nic improved erectile function in DMED rats possibly suppressing penile fibrosis by inhibiting Smad2/3 signaling. These results suggest a potential therapeutic repurposing of Nic as an adjuvant treatment in DMED.

Efficacy of CP-COV03 (a niclosamide-based inorganic nanohybrid product) against severe fever with thrombocytopenia syndrome virus in an in vitro model

Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne infectious disease caused by the SFTS virus (SFTSV). CP-COV03 is a novel antiviral candidate that significantly enhanced the bioavailability of niclosamide through inorganic-based drug delivery technology. The active pharmaceutical ingredient of CP-COV03, niclosamide, has been previously shown to possess broad-spectrum antiviral activity against over 30 different viruses in the in vitro tests. The aim of this study is to confirm the antiviral activity of CP-COV03 against the SFTSV in an in vitro model. Vero cells and SFTS viral stock NCCP43270, a 2015 Gangwon Province isolate, were used to obtain the 50% tissue culture infective dose of the virus. Vero cells seeded in 96-well plates were infected with SFTSV for 1 h. SFTSV-infected cells were treated with CP-COV03 at various concentrations of 0.1-100 μM and incubated for 7 days. On the seventh day of the culture, the cytopathic effect (CPE) of SFTSV was checked by microscopy and the cell viability was checked by using Cell Counting Kit-8 assay. The CPE reduced as the CP-COV03 concentration increased. The 50% inhibitory concentration (IC50) range of CP-COV03 was below 0.125 µM, as determined from the viral titers of culture supernatants collected on the third day posttreatment of CP-COV03. The plaque reduction assay showed that the IC50 of CP-COV03 was 1.893 µM, as determined from the percentage reduction of plaque counts for each drug concentration on the second day posttreatment with CP-COV03. This study suggests that CP-COV03 could be used as a potential antiviral agent for SFTS.IMPORTANCEWe demonstrated a concentration-dependent response and identified low a IC50 of CP-COV03. This result is comparable to other antiviral drugs used against viruses like severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We believe that our study makes a significant contribution to the literature as our findings suggest that CP-COV03 may serve as a potential treatment for SFTS, highlighting its importance in the field of antiviral research.

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.

Integrated ML-Based Strategy Identifies Drug Repurposing for Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) affects an estimated global population of around 3 million individuals. IPF is a medical condition with an unknown cause characterized by the formation of scar tissue in the lungs, leading to progressive respiratory disease. Currently, there are only two FDA-approved small molecule drugs specifically for the treatment of IPF and this has created a demand for the rapid development of drugs for IPF treatment. Moreover, denovo drug development is time and cost-intensive with less than a 10% success rate. Drug repurposing currently is the most feasible option for rapidly making the drugs to market for a rare and sporadic disease. Normally, the repurposing of drugs begins with a screening of FDA-approved drugs using computational tools, which results in a low hit rate. Here, an integrated machine learning-based drug repurposing strategy is developed to significantly reduce the false positive outcomes by introducing the predock machine-learning-based predictions followed by literature and GSEA-assisted validation and drug pathway prediction. The developed strategy is deployed to 1480 FDA-approved drugs and to drugs currently in a clinical trial for IPF to screen them against "TGFB1", "TGFB2", "PDGFR-a", "SMAD-2/3", "FGF-2", and more proteins resulting in 247 total and 27 potentially repurposable drugs. The literature and GSEA validation suggested that 72 of 247 (29.14%) drugs have been tried for IPF, 13 of 247 (5.2%) drugs have already been used for lung fibrosis, and 20 of 247 (8%) drugs have been tested for other fibrotic conditions such as cystic fibrosis and renal fibrosis. Pathway prediction of the remaining 142 drugs was carried out resulting in 118 distinct pathways. Furthermore, the analysis revealed that 29 of 118 pathways were directly or indirectly involved in IPF and 11 of 29 pathways were directly involved. Moreover, 15 potential drug combinations are suggested for showing a strong synergistic effect in IPF. The drug repurposing strategy reported here will be useful for rapidly developing drugs for treating IPF and other related conditions.

Niclosamide - encapsulated lipid nanoparticles for the reversal of pulmonary fibrosis

Pulmonary fibrosis (PF) is a serious and progressive fibrotic interstitial lung disease that is possibly life-threatening and that is characterized by fibroblast accumulation and collagen deposition. Nintedanib and pirfenidone are currently the only two FDA-approved oral medicines for PF. Some drugs such as antihelminthic drug niclosamide (Ncl) have shown promising therapeutic potentials for PF treatment. Unfortunately, poor aqueous solubility problems obstruct clinical application of these drugs. Herein, we prepared Ncl-encapsulated lipid nanoparticles (Ncl-Lips) for pulmonary fibrosis therapy. A mouse model of pulmonary fibrosis induced by bleomycin (BLM) was generated to assess the effects of Ncl-Lips and the mechanisms of reversing fibrosis in vivo. Moreover, cell models treated with transforming growth factor β1 (TGFβ1) were used to investigate the mechanism through which Ncl-Lips inhibit fibrosis in vitro. These findings demonstrated that Ncl-Lips could alleviate fibrosis, consequently reversing the changes in the levels of the associated marker. Moreover, the results of the tissue distribution experiment showed that Ncl-Lips had aggregated in the lung. Additionally, Ncl-Lips improved the immune microenvironment in pulmonary fibrosis induced by BLM. Furthermore, Ncl-Lips suppressed the TGFβ1-induced activation of fibroblasts and epithelial-mesenchymal transition (EMT) in epithelial cells. Based on these results, we demonstrated that Ncl-Lips is an efficient strategy for reversing pulmonary fibrosis via drug-delivery.

Niclosamide inhibits TGF-β1-induced fibrosis of human Tenon's fibroblasts by regulating the MAPK-ERK1/2 pathway

Preventing postoperative bleb scar formation is an effective way of improving glaucoma filtration surgery (GFS) outcome. Use of more effective antifibrotic drugs with fewer adverse effects may be a good way to address the problem. In the present study, we use a primary cell model, consisting of Tenon's fibroblasts obtained from patients with glaucoma, which were stimulated with TGF-β1 to induce the fibrotic phenotype. We explored the effects of niclosamide on TGF-β1-induced fibrosis in these cells and examined its underlying mechanism of action. A transcriptome sequencing assay was used to explore possible signaling pathways involved. Niclosamide inhibited cell proliferation and migration, and decreased the levels of alpha-smooth muscle actin, type I and type III collagen in human Tenon's fibroblasts induced by TGF-β1. Niclosamide also induced apoptosis and counteracted TGF-β1-induced cytoskeletal changes and extracellular matrix accumulation. Moreover, niclosamide decreased TGF-β1-induced phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2) protein expression in human Tenon's fibroblasts. The results indicate that niclosamide inhibits TGF-β1-induced fibrosis in human Tenon's fibroblasts by blocking the MAPK-ERK1/2 signaling pathway. Thus, niclosamide is a potentially promising antifibrotic drug that could improve glaucoma filtration surgery success rate.

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.

Niclosamide-loaded nanoparticles (Ncl-NPs) reverse pulmonary fibrosis in vivo and in vitro

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF), a life-threatening interstitial lung disease, is characterized by excessive activation and proliferation of fibroblasts and epithelial-mesenchymal transition (EMT) of alveolar epithelial cells (AEC) accompanied by a large amount of extracellular matrix aggregation. There are no therapies to reverse pulmonary fibrosis, and nintedanib and pirfenidone could only slow down the decline of lung function of IPF patients and delay their survival time. Niclosamide (Ncl) is an antihelminthic drug approved by FDA, which has been reported to have pleiotropic pharmacological activities in recent years, but it's almost complete insolubility in water limits its clinical application.

OBJECTIVES

To improve the water solubility of Ncl, explore its ability to reverse BLM-induced pulmonary fibrosis and its specific mechanism of action.

METHODS

The Niclosamide-loaded nanoparticles (Ncl-NPs) were formed by emulsification solvent evaporation method. A mouse model induced by bleomycin (BLM) was established to evaluate its effects and mechanisms of inhibiting and reversing fibrosis in vivo. The cell models treated by transforming growth factor-β1 (TGF-β1) were used to examine the mechanism of Ncl-NPs inhibiting fibrosis in vitro. Flow cytometry, IHC, IL-4-induced macrophage model and co-culture system were used to assess the effect of Ncl-NPs on M2 polarization of macrophages.

RESULTS

The Ncl-NPs improved the poor water solubility of Ncl. The lower dose of Ncl-NPs (2.5 mg/kg) showed the same effect of reversing established pulmonary fibrosis as free Ncl (5 mg/kg). Mechanistic studies revealed that Ncl-NPs blocked TGF-β/Smad and signaling transducer and activator of transcription 3 (Stat3) signaling pathways and inhibited the M2 polarization of macrophages. Additionally, H&E staining of the tissues initially showed the safety of Ncl-NPs.

CONCLUSION

These results indicate Ncl-NPs may serve as a new idea for the treatment of pulmonary fibrosis.

Promising small molecule anti-fibrotic agents: Newly developed or repositioned drugs targeting myofibroblast transdifferentiation

Fibrosis occurs in all organs and tissues except the brain, and its progression leads to dysfunction of affected organs. Fibrosis-induced organ dysfunction results from the loss of elasticity, strength, and functionality of tissues due to the extracellular matrix secreted by myofibroblasts that express smooth muscle-type actin as a marker. Myofibroblasts, which play a major role in fibrosis, were once thought to originate exclusively from activated fibroblasts; however, it is now clear that myofibroblasts are diverse in origin, from epithelial cells, endothelial cells, adipocytes, macrophages, and other cells. Fibrosis of vital organs, such as the heart, lungs, kidneys, and liver, is a serious chronic disease that ultimately leads to death. Currently, anti-cancer drugs have made remarkable progress, as evidenced by the development of many molecular-targeted drugs, and are making a significant contribution to improving the prognosis of cancer treatment. However, the development of anti-fibrotic agents, which also play an important role in prognosis, has lagged. In this review, the current knowledge regarding myofibroblasts is summarized, with particular attention given to their origin and transdifferentiation signaling pathways (e.g., TGF-β, Wnt/β-catenin, YAP/TAZ and AMPK signaling pathways). The development of new small molecule anti-fibrotic agents and the repositioning of existing drugs targeting myofibroblast transdifferentiation are discussed.

Niclosamide Attenuates Inflammation-Associated Profibrotic Responses in Human Subepithelial Lung Myofibroblasts

Niclosamide is a commonly used helminthicidic drug for the treatment of human parasitosis by helminths. Recently, efforts have been focusing on repurposing this drug for the treatment of other diseases, such as idiopathic pulmonary fibrosis. Subepithelial lung myofibroblasts (SELMs) isolated from tissue biopsies of patients undergoing surgery for lung cancer were stimulated with TNF-α (50 ng/mL), IL-1α (5 ng/mL), added alone or in combination, and TGF-β₁ (5 ng/mL). After treatment with niclosamide at 30 nM and 100 nM concentrations, expression of collagen type I, collagen type III, and fibronectin was studied by total RNA isolation and qRT-PCR and protein collagen secretion with the use of Sircol collagen assay. The migration of SELMs was assessed by a wound-healing assay. Niclosamide had no effect on baseline SELM fibrotic factor expression. When stimulated with TGF-β₁, IL-1α, and/or TNF-α, SELM expression of collagen type I, type III, and fibronectin were upregulated, as was the secretion of total collagen in the culture medium. Treatment with niclosamide attenuated the effects of cytokine stimulation leading to a notable decrease in the mRNA expression of collagen type I, type III, and fibronectin in a concentration-dependent manner. SELM collagen secretion was also reduced by niclosamide at 100 nM concentration when examined at the protein level. Migration of both TGF-β₁ stimulated and unstimulated SELMs was also inhibited by niclosamide. In this study, we highlight the anti-fibrotic properties of niclosamide on SELMs under stimulation with pro-fibrotic and pro-inflammatory cytokines, thus proposing this compound as a possible new therapeutic agent against lung fibrosis.

Repurposing Niclosamide as a Novel Anti-SARS-CoV-2 Drug by Restricting Entry Protein CD147

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to the global coronavirus disease 2019 (COVID-19) pandemic, and the search for effective treatments has been limited. Furthermore, the rapid mutations of SARS-CoV-2 have posed challenges to existing vaccines and neutralizing antibodies, as they struggle to keep up with the increased viral transmissibility and immune evasion. However, there is hope in targeting the CD147-spike protein, which serves as an alternative point for the entry of SARS-CoV-2 into host cells. This protein has emerged as a promising therapeutic target for the development of drugs against COVID-19. Here, we demonstrate that the RNA-binding protein Human-antigen R (HuR) plays a crucial role in the post-transcriptional regulation of CD147 by directly binding to its 3'-untranslated region (UTR). We observed a decrease in CD147 levels across multiple cell lines upon HuR depletion. Furthermore, we identified that niclosamide can reduce CD147 by lowering the cytoplasmic translocation of HuR and reducing CD147 glycosylation. Moreover, our investigation revealed that SARS-CoV-2 infection induces an upregulation of CD147 in ACE2-expressing A549 cells, which can be effectively neutralized by niclosamide in a dose-dependent manner. Overall, our study unveils a novel regulatory mechanism of regulating CD147 through HuR and suggests niclosamide as a promising therapeutic option against COVID-19.

Combination of Niclosamide and Pirfenidone Alleviates Pulmonary Fibrosis by Inhibiting Oxidative Stress and MAPK/Nf-κB and STATs Regulated Genes

The pathogenesis of pulmonary fibrosis (PF) is extremely complex and involves numerous intersecting pathways. The successful management of PF may require combining multiple agents. There is a growing body of evidence that suggests the potential benefits of niclosamide (NCL), an FDA-approved anthelminthic drug, in targeting different fibrogenesis molecules. This study aimed at investigating the anti-fibrotic potential of NCL alone and in combination with pirfenidone (PRF), an approved drug for PF, in a bleomycin (BLM) induced PF experimental model. PF was induced in rats by intratracheal BLM administration. The effect of NCL and PRF individually and in combination on different histological and biochemical parameters of fibrosis was investigated. Results revealed that NCL and PRF individually and in combination alleviated the histopathological changes, extracellular matrix deposition and myofibroblastic activation induced by BLM. NCL and PRF either individually or in combination inhibited the oxidative stress and subsequent pathways. They modulated the process of fibrogenesis by inhibiting MAPK/NF-κB and downstream cytokines. They inhibited STATs and downstream survival-related genes including BCL-2, VEGF, HIF-α and IL-6. Combining both drugs showed significant improvement in the tested markers in comparison to the monotherapy. NCL, therefore, has a potential synergistic effect with PRF in reducing the severity of PF.

Repurposing niclosamide as a novel anti-SARS-Cov-2 drug by restricting entry protein CD147

Background The burst of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is causing the global COVID-19 pandemic. But until today only limited numbers of drugs are discovered to treat COVID-19 patients. Even worse, the rapid mutations of SARS-CoV-2 compromise the effectiveness of existing vaccines and neutralizing antibodies due to the increased viral transmissibility and immune escape. CD147-spike protein, one of the entries of SRAR-CoV-2 into host cells, has been reported as a promising therapeutic target for developing drugs against COVID-19. Methods CRISPR-Cas9 induced gene knockout, western blotting, tet-off protein overexpression, ribonucleoprotein IP and RNA-IP were used to confirm the regulation of HuR on mRNA of CD147. Regulation of niclosamide on HuR nucleo-translocation was assessed by immunofluorescence staining of cell lines, IHC staining of tissue of mouse model and western blotting. Finally, the suppression of niclosamide on SARS-CoV-2 infection induced CD147 was evaluated by ACE2-expressing A549 cells and western blotting. Results We first discovered a novel regulation mechanism of CD147 via the RNA-binding protein HuR. We found that HuR regulates CD147 post-transcription by directly bound to its 3'-UTR. The loss of HuR reduced CD147 in multiple cell lines. Niclosamide inhibited CD147 function by blocking HuR cytoplasmic translocation and diminishing CD147 glycosylation. SARS-CoV-2 infection induced CD147 in ACE2-expressing A549 cells, which could be neutralized by niclosamide in a dose-dependent manner. Conclusion Together, our study reveals a novel regulation mechanism of CD147 and niclosamide can be repurposed as an effective COVID-19 drug by targeting the virus entry, CD147-spike protein.

Role of Ferroptosis in Regulating the Epithelial-Mesenchymal Transition in Pulmonary Fibrosis

Idiopathic pulmonary fibrosis is a chronic interstitial lung disease whose pathogenesis involves a complex interaction of cell types and signaling pathways. Lung epithelial cells responding to repeated injury experience persistent inflammation and sustained epithelial-mesenchymal transition (EMT). The persistence of EMT-induced signals generates extracellular matrix accumulation, thereby causing fibrosis. Ferroptosis is a newly characterized iron-dependent non-apoptotic regulated cell death. Increased iron accumulation can increase iron-induced oxidant damage in alveolar epithelial cells. Studies have demonstrated that iron steady states and oxidation steady states play an important role in the iron death regulation of EMT. This review summarizes the role of ferroptosis in regulating EMT in pulmonary fibrosis, aiming to provide a new idea for the prevention and treatment of this disease.

Pharmacological Inhibition of S100A4 Attenuates Fibroblast Activation and Renal Fibrosis

The TGF-β/Smad3 signaling pathway is an important process in the pathogenesis of kidney fibrosis. However, the molecular mechanisms are not completely elucidated. The current study examined the functional role of S100A4 in regulating TGF-β/Smad3 signaling in fibroblast activation and kidney fibrosis development. S100A4 was upregulated in the kidney in a murine model of renal fibrosis induced by folic acid nephropathy. Further, S100A4 was predominant in the tubulointerstitial cells of the kidney. Pharmacological inhibition of S100A4 with niclosamide significantly attenuated fibroblast activation, decreased collagen content, and reduced extracellular matrix protein expression in folic acid nephropathy. Overexpression of S100A4 in cultured renal fibroblasts significantly facilitated TGF-β1-induced activation of fibroblasts by increasing the expression of α-SMA, collagen-1 and fibronectin. In contrast, S100A4 knockdown prevented TGF-β1-induced activation of fibroblast and transcriptional activity of Smad3. Mechanistically, S100A4 interacts with Smad3 to stabilize the Smad3/Smad4 complex and promotes their translocation to the nucleus. In conclusion, S100A4 facilitates TGF-β signaling via interaction with Smad3 and promotes kidney fibrosis development. Manipulating S100A4 may provide a beneficial therapeutic strategy for chronic kidney disease.

A Niclosamide-releasing hot-melt extruded catheter prevents Staphylococcus aureus experimental biomaterial-associated infection

Biomaterial-associated infections are a major healthcare challenge as they are responsible for high disease burden in critically ill patients. In this study, we have developed drug-eluting antibacterial catheters to prevent catheter-related infections. Niclosamide (NIC), originally an antiparasitic drug, was incorporated into the polymeric matrix of thermoplastic polyurethane (TPU) via solvent casting, and catheters were fabricated using hot-melt extrusion technology. The mechanical and physicochemical properties of TPU polymers loaded with NIC were studied. NIC was released in a sustained manner from the catheters and exhibited in vitro antibacterial activity against Staphylococcus aureus and Staphylococcus epidermidis. Moreover, the antibacterial efficacy of NIC-loaded catheters was validated in an in vivo biomaterial-associated infection model using a methicillin-susceptible and methicillin-resistant strain of S. aureus. The released NIC from the produced catheters reduced bacterial colonization of the catheter as well as of the surrounding tissue. In summary, the NIC-releasing hot-melt extruded catheters prevented implant colonization and reduced the bacterial colonization of peri-catheter tissue by methicillin sensitive as well as resistant S. aureus in a biomaterial-associated infection mouse model and has good prospects for preclinical development.

Niclosamide-A promising treatment for COVID-19

Vaccines have reduced the transmission and severity of COVID-19, but there remains a paucity of efficacious treatment for drug-resistant strains and more susceptible individuals, particularly those who mount a suboptimal vaccine response, either due to underlying health conditions or concomitant therapies. Repurposing existing drugs is a timely, safe and scientifically robust method for treating pandemics, such as COVID-19. Here, we review the pharmacology and scientific rationale for repurposing niclosamide, an anti-helminth already in human use as a treatment for COVID-19. In addition, its potent antiviral activity, niclosamide has shown pleiotropic anti-inflammatory, antibacterial, bronchodilatory and anticancer effects in numerous preclinical and early clinical studies. The advantages and rationale for nebulized and intranasal formulations of niclosamide, which target the site of the primary infection in COVID-19, are reviewed. Finally, we give an overview of ongoing clinical trials investigating niclosamide as a promising candidate against SARS-CoV-2.

Niclosamide Ethanolamine Salt Alleviates Idiopathic Pulmonary Fibrosis by Modulating the PI3K-mTORC1 Pathway

Idiopathic pulmonary fibrosis (IPF) is an interstitial pneumonia characterized by chronic progressive fibrosis, ultimately leading to respiratory failure and early mortality. Although not fully explored, the major causative factors in IPF pathogenesis are dysregulated fibroblast proliferation and excessive accumulation of extracellular matrix (ECM) deposited by myofibroblasts differentiated from pulmonary fibroblasts. More signalling pathways, including the PI3K-Akt-mTOR and autophagy pathways, are involved in IPF pathogenesis. Niclosamide ethanolamine salt (NEN) is a highly effective multitarget small-molecule inhibitor reported in antitumor studies. Here, we reported that in an IPF animal model treated with NEN for 14 days, attractive relief of pulmonary function and hydroxyproline content were observed. To further explore, the therapeutic effect of NEN in IPF and pathological changes in bleomycin-challenged mouse lung sections were assessed. Additionally, the effects of NEN on abnormal proliferation and ECM production in IPF cell models established with TGF-β1-stimulated A549 cells or DHLF-IPF cells were studied. In nonclinical studies, NEN ameliorated lung function and histopathological changes in bleomycin-challenged mice, and the lung hydroxyproline content was significantly diminished with NEN treatment. In vitro, NEN inhibited PI3K-mTORC1 signalling and arrested the cell cycle to prevent uncontrolled fibroblast proliferation. Additionally, NEN inhibited TGF-β1-induced epithelial–mesenchymal transition (EMT) and ECM accumulation via the mTORC1-4EBP1 axis. Furthermore, NEN-activated noncanonical autophagy resensitized fibroblasts to apoptosis. The above findings demonstrated the potential antifibrotic effect of NEN mediated via modulation of the PI3K-mTORC1 and autophagy pathways. These data provide strong evidence for a therapeutic role for NEN in IPF.

Identification of hub genes and key pathways of paraquat-induced human embryonic pulmonary fibrosis by bioinformatics analysis and in vitro studies

Objective: Paraquat (N,N0-dimethyl-4,40-bipyridinium dichloride;PQ) is a highly toxic pesticide, which usually leads to acute lung injury and subsequent development of pulmonary fibrosis. The exact mechanism underlying PQ-induced lung fibrosis remain largely unclear and as yet, no specific treatment drugs have been approved. Our study aimed to identify its potential mechanisms of PQ-induced fibrosis through a modeling study in vitro studies and bioinformatics analysis.

Methods: Gene expression datasets associated with PQ-induced lung fibrosis were obtained from the Gene Expression Omnibus, wherefrom differentially expressed genes (DEGs) were identified using GEO2R. Functional enrichment analyses were performed using the Database for Annotation Visualization and Integrated Discovery. The DEGs analyzed by a protein–protein interaction network was constructed with the Search Tool for the Retrieval of Interacting Genes database. MCODE, a Cytoscape plugin, was subsequently used to identify the most significant modules. The expression of the key genes in PQ-induced pulmonary fibrotic tissues was verified by reverse transcription-quantitative PCR (RT-qPCR).

Results: Two datasets were analyzed and revealed 92 overlapping DEGs. Functional analysis demonstrated that these 92 DEGs were enriched in the ‘TNF signaling pathway’, ‘CXCR chemokine receptor binding’, and ‘core promoter binding’. Moreover, nine hub genes were identified from the protein–protein interaction network formed from the DEGs. These results suggested that the TNF signaling pathway and nine hub genes are possibly involved in PQ-induced lung fibrosis progression.

Conclusions: This integrative analysis identified candidate genes and pathways potentially involved in PQ-induced lung fibrosis, and could benefit future development of novel approaches for controlling and treating this disease.

The ameliorative effect of niclosamide on bile duct ligation induced liver fibrosis via suppression of NOTCH and Wnt pathways

Liver fibrosis is the conjoint consequence of almost all chronic liver diseases. Cholestatic liver injury is a significant stimulus for fibrotic liver. This study was conducted to investigate the hepatoprotective effect of niclosamide as a NOTCH inhibitor and on the Wnt pathway against cholestatic liver fibrosis (CLF) which was experimentally induced by bile duct ligation (BDL). Rats were randomly divided into five main groups (6 per group): sham, BDL, BDL/niclosamide 5, BDL/niclosamide 10 and niclosamide 10 only group. Niclosamide was administered intraperitoneally (i.p.) for 4 weeks starting at the same day of surgery at doses 5 and 10 mg/kg. Liver function, cholestasis, oxidative stress, inflammation, liver fibrosis, NOTCH signaling pathway and Wnt pathway markers were assessed. Niclosamide (5 and 10 mg/kg) significantly reduced liver enzymes levels, oxidative stress, inflammation and phosphorylated signal transducer and activator of transcription3 (p-STAT3). Niclosamide (5 and 10 mg/kg) also significantly reduced NOTCH pathway (Jagged1, NOTCH2, NOTCH3, HES1, SOX9), Wnt pathway (Wnt5B, and Wnt10A), and fibrosis (transforming growth factor-beta1 (TGF-β1), alpha smooth muscle actin (α-SMA) and collagen deposition with more prominent effect of the higher dose 10 mg/kg. So, this study presents nicloamide as a promising antifibrotic agent in CLF through inhibition of NOTCH and Wnt pathways.

The S100 Protein Family as Players and Therapeutic Targets in Pulmonary Diseases

The S100 protein family consists of over 20 members in humans that are involved in many intracellular and extracellular processes, including proliferation, differentiation, apoptosis, Ca₂⁺ homeostasis, energy metabolism, inflammation, tissue repair, and migration/invasion. Although there are structural similarities between each member, they are not functionally interchangeable. The S100 proteins function both as intracellular Ca²⁺ sensors and as extracellular factors. Dysregulated responses of multiple members of the S100 family are observed in several diseases, including the lungs (asthma, chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, cystic fibrosis, pulmonary hypertension, and lung cancer). To this degree, extensive research was undertaken to identify their roles in pulmonary disease pathogenesis and the identification of inhibitors for several S100 family members that have progressed to clinical trials in patients for nonpulmonary conditions. This review outlines the potential role of each S100 protein in pulmonary diseases, details the possible mechanisms observed in diseases, and outlines potential therapeutic strategies for treatment.

Targeting S100A4 with niclosamide attenuates inflammatory and profibrotic pathways in models of amyotrophic lateral sclerosis

Background

An increasing number of studies evidences that amyotrophic lateral sclerosis (ALS) is characterized by extensive alterations in different cell types and in different regions besides the CNS. We previously reported the upregulation in ALS models of a gene called fibroblast-specific protein-1 or S100A4, recognized as a pro-inflammatory and profibrotic factor. Since inflammation and fibrosis are often mutual-sustaining events that contribute to establish a hostile environment for organ functions, the comprehension of the elements responsible for these interconnected pathways is crucial to disclose novel aspects involved in ALS pathology.

Methods

Here, we employed fibroblasts derived from ALS patients harboring the C9orf72 hexanucleotide repeat expansion and ALS patients with no mutations in known ALS-associated genes and we downregulated S100A4 using siRNA or the S100A4 transcriptional inhibitor niclosamide. Mice overexpressing human FUS were adopted to assess the effects of niclosamide in vivo on ALS pathology.

Results

We demonstrated that S100A4 underlies impaired autophagy and a profibrotic phenotype, which characterize ALS fibroblasts. Indeed, its inhibition reduces inflammatory, autophagic, and profibrotic pathways in ALS fibroblasts, and interferes with different markers known as pathogenic in the disease, such as mTOR, SQSTM1/p62, STAT3, α-SMA, and NF-κB. Importantly, niclosamide in vivo treatment of ALS-FUS mice reduces the expression of S100A4, α-SMA, and PDGFRβ in the spinal cord, as well as gliosis in central and peripheral nervous tissues, together with axonal impairment and displays beneficial effects on muscle atrophy, by promoting muscle regeneration and reducing fibrosis.

Conclusion

Our findings show that S100A4 has a role in ALS-related mechanisms, and that drugs such as niclosamide which are able to target inflammatory and fibrotic pathways could represent promising pharmacological tools for ALS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02184-1.

S100A4 in the Physiology and Pathology of the Central and Peripheral Nervous System

S100A4 is a member of the large family of S100 proteins, exerting a broad range of intracellular and extracellular functions that vary upon different cellular contexts. While S100A4 has long been implicated mainly in tumorigenesis and metastatization, mounting evidence shows that S100A4 is a key player in promoting pro-inflammatory phenotypes and organ pro-fibrotic pathways in the liver, kidney, lung, heart, tendons, and synovial tissues. Regarding the nervous system, there is still limited information concerning S100A4 presence and function. It was observed that S100A4 exerts physiological roles contributing to neurogenesis, cellular motility and chemotaxis, cell differentiation, and cell-to cell communication. Furthermore, S100A4 is likely to participate to numerous pathological processes of the nervous system by affecting the functions of astrocytes, microglia, infiltrating cells and neurons and thereby modulating inflammation and immune reactions, fibrosis as well as neuronal plasticity and survival. This review summarizes the current state of knowledge concerning the localization, deregulation, and possible functions of S100A4 in the physiology of the central and peripheral nervous system. Furthermore, we highlight S100A4 as a gene involved in the pathogenesis of neurological disorders such as brain tumors, neurodegenerative diseases, and acute injuries.

S100A2 Silencing Relieves Epithelial-Mesenchymal Transition in Pulmonary Fibrosis by Inhibiting the Wnt/β-Catenin Signaling Pathway

Pulmonary fibrosis (PF) is a progressive and lethal disease with poor prognosis. S100A2 plays an important role in the progression of cancer. However, the role of S100A2 in PF has not yet been reported. In this study, we explored the potential role of S100A2 in PF and its potential molecular mechanisms. Increased expression of S100A2 was first observed in lung tissues of PF patients. We found that downregulation of S100A2 inhibited the transforming growth factor-β1 (TGF-β1)-induced epithelial-mesenchymal transition (EMT) in A549 cells. Mechanically, TGF-β1 upregulated β-catenin and the phosphorylation of glycogen synthase kinase-3β, which was blocked by silencing S100A2 in vitro. Furthermore, lithium chloride (activator of the Wnt/β-catenin signaling pathway) effectively rescued S100A2 knockdown-mediated inhibition of EMT in PF. In conclusion, these findings demonstrate that downregulation of S100A2 alleviated PF through inhibiting EMT. S100A2 is a promising potential target for further understanding the mechanism and developing a strategy for the treatment of PF and other EMT-associated diseases.

Latest progress on the molecular mechanisms of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a serious life-threatening lung disease, and the median survival period of PF patients after diagnosis is only 2.5-3.5 years. At present, there are no effective drugs or therapeutics to reverse or even inhibit IPF. The main pathological characteristics of pulmonary fibrosis (PF) include damage to alveolar epithelial cells, fibroblast activation and extracellular matrix accumulation, which gradually lead to damage to the lung structure and decreased lung function. It is important to understand the cellular and molecular mechanisms of PF comprehensively and clearly. In this paper, critical signaling pathways related to PF were reviewed to present updates on the molecular mechanisms of PF.

The role of WNT/β-catenin signaling pathway and glutamine metabolism in the pathogenesis of CCl4-induced liver fibrosis: Repositioning of niclosamide and concerns about lithium

BACKGROUND

Liver fibrosis is a serious health problem which may lead to advanced liver cirrhosis and hepatocellular carcinoma.

OBJECTIVE

The present study aimed to investigate the role of Wnt/β-catenin signaling pathway and glutamine aminohydrolase enzyme (l-glutaminase) in the pathogenesis of liver fibrosis and the potential benefits of niclosamide in treating liver fibrosis.

METHODS

Ninety male Albino rats were divided into 6 equal groups (n = 15) as follows: a normal control group (NC), CCl₄-only treated group (Fib.) which received 1 mg/kg CCl₄ two times weekly, niclosamide-treated group (Niclo.) which received 5 mg/kg of niclosamide one time daily, lithium chloride-treated group (LiCl) which received 100 mg/kg of LiCl one time daily, niclosamide-and-CCl₄-treated group (Niclo. + Fib.) which received same doses of niclosamide and CCl₄ given to other groups, and finally lithium chloride-and-CCl₄-treated rat group (LiCl + Fib.) which received same doses of LiCl and CCl₄ given to other groups. All treatments were administered orally for 8 weeks. Liver tissue was assessed for l-hydroxyproline, beta-catenin (β-catenin), l-glutaminase activity, as well as the gene expression of transforming growth factor beta-1 (TGF-β1) and Dishevelled-2 (Dvl2). Histopathological and immunohistochemical analyses of alpha smooth muscle actin α-SMA were performed. Serum alanine transaminase (ALT), aspartate transaminase (AST), and total bilirubin were measured.

RESULTS

The group of niclosamide-and-CCl₄-treated rats showed a significant decrease in total bilirubin, ALT and AST, β-catenin, l-hydroxyproline, l-glutaminase activity, and gene expression of TGF-β1 and Dvl2. Moreover, the liver tissue in this group of rats showed mild α-SMA reactivity compared with the rats treated with CCl₄ only (fibrosis group). On the other hand, lithium chloride-and-CCl₄-treated rats showed a significant increase in liver indices, TGF-β1 expression, β-catenin, l-hydroxyproline, and l-glutaminase activity with severe α-SMA reactivity and apoptosis in the liver tissue.

CONCLUSIONS

Niclosamide protected rats against liver fibrosis by inhibiting the Wnt/β-catenin pathway and glutaminolysis.

Exploring the new horizons of drug repurposing: A vital tool for turning hard work into smart work

Drug discovery and development are long and financially taxing processes. On an average it takes 12-15 years and costs 1.2 billion USD for successful drug discovery and approval for clinical use. Many lead molecules are not developed further and their potential is not tapped to the fullest due to lack of resources or time constraints. In order for a drug to be approved by FDA for clinical use, it must have excellent therapeutic potential in the desired area of target with minimal toxicities as supported by both pre-clinical and clinical studies. The targeted clinical evaluations fail to explore other potential therapeutic applications of the candidate drug. Drug repurposing or repositioning is a fast and relatively cheap alternative to the lengthy and expensive de novo drug discovery and development. Drug repositioning utilizes the already available clinical trials data for toxicity and adverse effects, at the same time explores the drug's therapeutic potential for a different disease. This review addresses recent developments and future scope of drug repositioning strategy.

The S100A4 Transcriptional Inhibitor Niclosamide Reduces Pro-Inflammatory and Migratory Phenotypes of Microglia: Implications for Amyotrophic Lateral Sclerosis

S100A4, belonging to a large multifunctional S100 protein family, is a Ca²⁺-binding protein with a significant role in stimulating the motility of cancer and immune cells, as well as in promoting pro-inflammatory properties in different cell types. In the CNS, there is limited information concerning S100A4 presence and function. In this study, we analyzed the expression of S100A4 and the effect of the S100A4 transcriptional inhibitor niclosamide in murine activated primary microglia. We found that S100A4 was strongly up-regulated in reactive microglia and that niclosamide prevented NADPH oxidase 2, mTOR (mammalian target of rapamycin), and NF-κB (nuclear factor-kappa B) increase, cytoskeletal rearrangements, migration, and phagocytosis. Furthermore, we found that S100A4 was significantly up-regulated in astrocytes and microglia in the spinal cord of a transgenic rat SOD1-G93A model of amyotrophic lateral sclerosis. Finally, we demonstrated the increased expression of S100A4 also in fibroblasts derived from amyotrophic lateral sclerosis (ALS) patients carrying SOD1 pathogenic variants. These results ascribe S100A4 as a marker of microglial reactivity, suggesting the contribution of S100A4-regulated pathways to neuroinflammation, and identify niclosamide as a possible drug in the control and attenuation of reactive phenotypes of microglia, thus opening the way to further investigation for a new application in neurodegenerative conditions.