Discovery of a pyrano[2,3-b]pyridine derivative YX-2102 as a cannabinoid receptor 2 agonist for alleviating lung fibrosis

Discovery of novel selective HDAC6 inhibitors via a scaffold hopping approach for the treatment of idiopathic pulmonary fibrosis (IPF) in vitro and in vivo

Idiopathic pulmonary fibrosis (IPF) is a progressive, irreversible, and fatal pulmonary disease. Owing to its complex pathogenesis and lack of effective treatment, patients have a short survival time after diagnosis. Although pirfenidone and nintedanib can mitigate declines in lung function, neither has stopped the progression of IPF nor significantly improved long-term survival in patients. HDAC6 inhibitors have been reported to inhibit TGF-β1-induced collagen expression to protect mice from pulmonary fibrosis, and this pharmacological mechanism has been supported by immunohistochemical studies of HDAC6 overexpression in IPF lung tissue. In this study, a series of novel derivatives were obtained based on the reported active compounds through the ring closure strategy in scaffold hopping theory. Compound W28 was selected from in vitro screening for better HDAC6 selectivity, and it was used for in-depth pharmacokinetic and pharmacodynamic studies. Detailed molecular docking studies, molecular dynamics (MD) simulations and the structure-activity relationship (SAR) discussion will contribute to guiding the design of new molecules. In further studies, the ability of W28 to inhibit the IPF phenotype was confirmed, and the corresponding pharmacological mechanism was also demonstrated. Moreover, the pharmacokinetic characteristics of W28 were also tested to guide pharmacodynamic studies in vivo, and the therapeutic effect of W28 on bleomycin-induced pulmonary fibrosis in mice was found to be satisfactory. The results reported in this paper may provide a reference for promoting the discovery of new selective HDAC6 inhibitors as drug molecules for the treatment of IPF.

Natural products for anti-fibrotic therapy in idiopathic pulmonary fibrosis: marine and terrestrial insights

Idiopathic Pulmonary Fibrosis (IPF) is a chronic fibrotic interstitial lung disease (ILD) of unknown etiology, characterized by increasing incidence and intricate pathogenesis. Current FDA-approved drugs suffer from significant side effects and limited efficacy, highlighting the urgent need for innovative therapeutic agents for IPF. Natural products (NPs), with their multi-target and multifaceted properties, present promising candidates for new drug development. This review delineates the anti-fibrotic pathways and targets of various natural products based on the established pathological mechanisms of IPF. It encompasses over 20 compounds, including flavonoids, saponins, polyphenols, terpenoids, natural polysaccharides, cyclic peptides, deep-sea fungal alkaloids, and algal proteins, sourced from both terrestrial and marine environments. The review explores their potential roles in mitigating pulmonary fibrosis, such as inhibiting inflammatory responses, protecting against lipid peroxidation damage, suppressing mesenchymal cell activation and proliferation, inhibiting fibroblast migration, influencing the synthesis and secretion of pro-fibrotic factors, and regulating extracellular matrix (ECM) synthesis and degradation. Additionally, it covers various in vivo and in vitro disease models, methodologies for analyzing marker expression and signaling pathways, and identifies potential new therapeutic targets informed by the latest research on IPF pathogenesis, as well as challenges in bioavailability and clinical translation. This review aims to provide essential theoretical and technical insights for the advancement of novel anti-pulmonary fibrosis drugs.

Therapeutic potential of agents targeting cannabinoid type 2 receptors in organ fibrosis

The endocannabinoid system has garnered attention as a potential therapeutic target in a range of pathological disorders. Cannabinoid receptors type 2 (CB2) are a class of G protein-coupled receptors responsible for transmitting intracellular signals triggered by both endogenous and exogenous cannabinoids, including those derived from plants (phytocannabinoids) or manufactured synthetically (synthetic cannabinoids). Recent recognition of the role of CB2 receptors in fibrosis has fueled interest in therapeutic targeting of CB2 receptors in fibrosis. Fibrosis is characterized by the alteration of the typical cellular composition within the tissue parenchyma, resulting from exposure to diverse etiological factors. The pivotal function of CB2 agonists has been widely recognized in the regulation of inflammation, fibrogenesis, and various other biological pathologies. The modulation of CB2 receptors, whether by enhancing their expression or activating their function, has the potential to provide benefits in numerous conditions, particularly by avoiding any associated adverse effects on the central nervous system. The sufficient activation of CB2 receptors resulted in the complete suppression of gene expression related to transforming growth factor β1 and its subsequent fibrogenic response. Multiple reports have also indicated the diverse functions that CB2 agonists possess in mitigating chronic inflammation and subsequent fibrosis development in various types of tissues. While currently in the preclinical stage, the advancement of CB2 compounds has garnered significant attention within the realm of drug discovery. This review presents a comprehensive synthesis of various independent experimental studies elucidating the pivotal role of identified natural and synthetic CB2 agonists in the pathophysiology of organ fibrosis, specifically in the cardiac, hepatic, and renal systems.

Activating SRC/MAPK signaling via 5-HT1A receptor contributes to the effect of vilazodone on improving thrombocytopenia

Thrombocytopenia caused by long-term radiotherapy and chemotherapy exists in cancer treatment. Previous research demonstrates that 5-Hydroxtrayptamine (5-HT) and its receptors induce the formation of megakaryocytes (MKs) and platelets. However, the relationships between 5-HT1A receptor (5-HTR1A) and MKs is unclear so far. We screened and investigated the mechanism of vilazodone as a 5-HTR1A partial agonist in promoting MK differentiation and evaluated its therapeutic effect in thrombocytopenia. We employed a drug screening model based on machine learning (ML) to screen the megakaryocytopoiesis activity of Vilazodone (VLZ). The effects of VLZ on megakaryocytopoiesis were verified in HEL and Meg-01 cells. Tg (itga2b: eGFP) zebrafish was performed to analyze the alterations in thrombopoiesis. Moreover, we established a thrombocytopenia mice model to investigate how VLZ administration accelerates platelet recovery and function. We carried out network pharmacology, Western blot, and immunofluorescence to demonstrate the potential targets and pathway of VLZ. VLZ has been predicted to have a potential biological action. Meanwhile, VLZ administration promotes MK differentiation and thrombopoiesis in cells and zebrafish models. Progressive experiments showed that VLZ has a potential therapeutic effect on radiation-induced thrombocytopenia in vivo. The network pharmacology and associated mechanism study indicated that SRC and MAPK signaling are both involved in the processes of megakaryopoiesis facilitated by VLZ. Furthermore, the expression of 5-HTR1A during megakaryocyte differentiation is closely related to the activation of SRC and MAPK. Our findings demonstrated that the expression of 5-HTR1A on MK, VLZ could bind to the 5-HTR1A receptor and further regulate the SRC/MAPK signaling pathway to facilitate megakaryocyte differentiation and platelet production, which provides new insights into the alternative therapeutic options for thrombocytopenia.