Discovery of an Oxycyclohexyl Acid Lysophosphatidic Acid Receptor 1 (LPA1) Antagonist BMS-986278 for the Treatment of Pulmonary Fibrotic Diseases

Discovery of GS-2278, a Potent and Selective LPAR1 Antagonist for the Treatment of Idiopathic Pulmonary Fibrosis

We describe the discovery and preclinical characterization of a potent and selective lysophosphatidic acid receptor 1 (LPAR1) antagonist with a direct-acting antifibrotic mechanism. 18a was initially identified as a potent non-carboxylic acid LPAR1 antagonist in an LPA-induced myocardin-related transcription factor A (MRTF-A) nuclear translocation assay. Modifications to the aromatic elements in the structure allowed for improvements in metabolic stability and the mitigation of GSH adduct formation, but in vitro to in vivo clearance disconnects were observed with several potent sulfonamides (e.g., 27b) across preclinical species. Through modification of the sulfonamide, 42 (GS-2278) emerged as a potent LPAR1 antagonist with a suitable in vitro profile and desirable pharmacokinetic properties for oral QD dosing. GS-2278 dose-dependently blocked LPA-induced histamine release and demonstrated efficacy in an interventional model of bleomycin-induced lung fibrosis. However, CNS-related toxicity was observed in dogs, and based on these findings, the clinical development of GS-2278 for IPF was halted.

What Is on the Horizon for Treatments in Idiopathic Pulmonary Fibrosis?

Idiopathic pulmonary fibrosis (IPF) is a progressive and often fatal lung disease most commonly encountered in older individuals. Several decades of research have contributed to a better understanding of its pathogenesis, though only two drugs thus far have shown treatment efficacy, i.e., by slowing the decline of lung function. The pathogenesis of IPF remains incompletely understood and involves multiple complex interactions and mechanisms working in tandem or separately to result in unchecked deposition of extracellular matrix components and collagen characteristic of the disease. These mechanisms include aberrant response to injury in the alveolar epithelium, inappropriate communication between epithelial cells and mesenchymal cells, imbalances between oxidative injury and tissue repair, recruitment of inflammatory pathways that induce fibrosis, and cell senescence leading to sustained activation and proliferation of fibroblasts and myofibroblasts. Targeted approaches to each of these mechanistic pathways have led to recent clinical studies evaluating the safety and efficacy of several agents. This review highlights selected concepts in the pathogenesis of IPF as a rationale for understanding current or future therapeutic approaches, followed by a review of several selected agents and their recent or active clinical studies. Current novel therapies include approaches to attenuating or modifying specific cellular or signaling processes in the fibrotic pathway, modifying inflammatory and metabolic derangements, and minimizing inappropriate cell senescence.

Bronchopulmonary dysplasia demonstrates dysregulated autotaxin/lysophosphatidic acid signaling in a neonatal mouse model

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a chronic lung disease affecting premature infants who require oxygen supplementation and ventilator therapy to support their underdeveloped lungs. Autotaxin (ATX), an enzyme that generates the bioactive phospholipid lysophosphatidic acid (LPA), which acts via G-protein coupled receptors, has been implicated in numerous pulmonary diseases. In this study, we explored the pathophysiological role of the ATX/LPA signaling pathway in BPD.

METHODS

Neonatal mice were exposed to normoxia or hyperoxia (85%) for 14 days from birth while being treated with vehicle, ATX inhibitor or LPA receptor 1 (LPA1) inhibitor. In vitro studies utilized human lung fibroblast (HLF) cells exposed to room air, 85% oxygen, or LPA for varying time periods. Supernatants and cells were collected for assays and Western blotting.

RESULTS

Animals exposed to hyperoxia showed elevated expression of ATX, ATX activity, and LPA1. Inhibiting ATX or LPA1 improved alveolarization, reduced inflammation, and mitigated extracellular matrix deposition and lysyl oxidase (LOX) expression. LPA1 inhibition leading to reduced LOX expression was associated with a reduction in phosphorylation of AKT.

CONCLUSION

Hyperoxia increases the expression of ATX and LPA1 associated with increased LOX in the lungs. Targeting the ATX/LPA1 pathway could be a potential therapeutic approach to BPD.

IMPACT

Exposure to hyperoxia increases the expression and activity of autotaxin (ATX), as well as expression of LPA receptor 1 (LPA1). Increased expression of ATX influences extra cellular matrix (ECM) remodeling. Inhibitors targeting the ATX/LPA pathway could offer a new therapeutic approach to bronchopulmonary dysplasia (BPD), potentially mitigating ECM deposition and improving lung development.

Emerging pharmacological options in the treatment of idiopathic pulmonary fibrosis (IPF)

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is a progressive-fibrosing lung disease with a median survival of less than 5 years. Currently, two agents, pirfenidone and nintedanib are approved for this disease, and both have been shown to reduce the rate of decline in lung function in patients with IPF. However, both have significant adverse effects and neither completely arrest the decline in lung function.

AREAS COVERED

Thirty experimental agents with unique mechanisms of action that are being evaluated for the treatment of IPF are discussed. These agents work through various mechanisms of action, these include inhibition of transcription nuclear factor k-B on fibroblasts, reduced expression of metalloproteinase 7, the generation of more lysophosphatidic acids, blocking the effects of transforming growth factor ß, and reducing reactive oxygen species as examples of some unique mechanisms of action of these agents.

EXPERT OPINION

New drug development has the potential to expand the treatment options available in the treatment of IPF patients. It is expected that the adverse drug effect profiles will be more favorable than current agents. It is further anticipated that these new agents or combinations of agents will arrest the fibrosis, not just slow the fibrotic process.

Lysophosphatidic Acid Receptor 1 (LPA1) Antagonists as Potential Migrastatics for Triple Negative Breast Cancer

Metastasis is responsible for about 90 % of cancer deaths. Anti-metastatic drugs, termed as migrastatics, offer a distinctive therapeutic approach to address cancer migration and invasion. However, therapeutic exploitation of metastasis-specific targets remains limited, and the effective prevention and suppression of metastatic cancer continue to be elusive. Lysophosphatidic acid receptor 1 (LPA1) is activated by an endogenous lipid molecule LPA, leading to a diverse array of cellular activities. Previous studies have shown that the LPA/LPA1 axis supports the progression of metastasis for many types of cancer. In this study, we report the synthesis and biological evaluation of fluorine-containing triazole derivatives as potent LPA1 antagonists, offering potential as migrastatic drugs for triple negative breast cancer (TNBC). In particular, compound 12 f, the most potent and highly selective in this series with an IC50 value of 16.0 nM in the cAMP assay and 18.4 nM in the calcium mobilization assay, inhibited cell survival, migration, and invasion in the TNBC cell line. Interestingly, the compound did not induce apoptosis in TNBC cells and demonstrated no cytotoxic effects. These results highlight the potential of LPA1 as a migrastatic target. Consequently, the LPA1 antagonists developed in this study hold promise as potential migrastatic candidates for TNBC.

Pathological mechanisms and novel drug targets in fibrotic interstitial lung disease

BACKGROUND

Interstitial lung diseases (ILDs) are a diverse group of conditions characterized by inflammation and fibrosis in the lung. In some patients with ILD, a progressive fibrotic phenotype develops, which is associated with an irreversible decline in lung function and a poor prognosis.

MAIN BODY

The pathological mechanisms that underlie this process culminate in fibroblast activation, proliferation, and differentiation into myofibroblasts, which deposit extracellular matrix proteins and result in fibrosis. Upstream of fibroblast activation, epithelial cell injury and immune activation are known initiators of fibrosis progression, with multiple diverse cell types involved. Recent years have seen an increase in our understanding of the complex and interrelated processes that drive fibrosis progression in ILD, in part due to the advent of single-cell RNA sequencing technology and integrative multiomics analyses. Novel pathological mechanisms have been identified, which represent new targets for drugs currently in clinical development. These include phosphodiesterase 4 inhibitors and other molecules that act on intracellular cyclic adenosine monophosphate signaling, as well as inhibitors of the autotaxin-lysophosphatidic acid axis and  α v  integrins. Here, we review current knowledge and recent developments regarding the pathological mechanisms that underlie progressive fibrotic ILD, including potential therapeutic targets.

CONCLUSION

Knowledge of the pathological mechanisms that drive progressive fibrosis in patients with ILD has expanded, with the role of alveolar endothelial cells, the immune system, and fibroblasts better elucidated. Drugs that target novel mechanisms hold promise for expanding the future therapeutic armamentarium for progressive fibrotic ILD.

Molecular Pathways Governing the Termination of Liver Regeneration

The liver has the unique capacity to regenerate, and up to 70% of the liver can be removed without detrimental consequences to the organism. Liver regeneration is a complex process involving multiple signaling networks and organs. Liver regeneration proceeds through three phases: the initiation phase, the growth phase, and the termination phase. Termination of liver regeneration occurs when the liver reaches a liver-to-body weight that is required for homeostasis, the so-called "hepatostat." The initiation and growth phases have been the subject of many studies. The molecular pathways that govern the termination phase, however, remain to be fully elucidated. This review summarizes the pathways and molecules that signal the cessation of liver regrowth after partial hepatectomy and answers the question, "What factors drive the hepatostat?" SIGNIFICANCE STATEMENT: Unraveling the pathways underlying the cessation of liver regeneration enables the identification of druggable targets that will allow us to gain pharmacological control over liver regeneration. For these purposes, it would be useful to understand why the regenerative capacity of the liver is hampered under certain pathological circumstances so as to artificially modulate the regenerative processes (e.g., by blocking the cessation pathways) to improve clinical outcomes and safeguard the patient's life.

Downregulation of HMGCS2 mediated AECIIs lipid metabolic alteration promotes pulmonary fibrosis by activating fibroblasts

BACKGROUND

Abnormal lipid metabolism has recently been reported as a crucial signature of idiopathic pulmonary fibrosis (IPF). However, the origin and biological function of the lipid and possible mechanisms of increased lipid content in the pathogenesis of IPF remains undetermined.

METHODS

Oil-red staining and immunofluorescence analysis were used to detect lipid accumulation in mouse lung fibrosis frozen sections, Bleomycin-treated human type II alveolar epithelial cells (AECIIs) and lung fibroblast. Untargeted Lipid omics analysis was applied to investigate differential lipid species and identified LysoPC was utilized to treat human lung fibroblasts and mice. Microarray and single-cell RNA expression data sets identified lipid metabolism-related differentially expressed genes. Gain of function experiment was used to study the function of 3-hydroxy-3-methylglutaryl-Coa Synthase 2 (HMGCS2) in regulating AECIIs lipid metabolism. Mice with AECII-HMGCS2 high were established by intratracheally delivering HBAAV2/6-SFTPC- HMGCS2 adeno-associated virus. Western blot, Co-immunoprecipitation, immunofluorescence, site-directed mutation and flow cytometry were utilized to investigate the mechanisms of HMGCS2-mediated lipid metabolism in AECIIs.

RESULTS

Injured AECIIs were the primary source of accumulated lipids in response to Bleomycin stimulation. LysoPCs released by injured AECIIs could activate lung fibroblasts, thus promoting the progression of pulmonary fibrosis. Mechanistically, HMGCS2 was decreased explicitly in AECIIs and ectopic expression of HMGCS2 in AECIIs using the AAV system significantly alleviated experimental mouse lung fibrosis progression via modulating lipid degradation in AECIIs through promoting CPT1A and CPT2 expression by interacting with PPARα.

CONCLUSIONS

These data unveiled a novel etiological mechanism of HMGCS2-mediated AECII lipid metabolism in the genesis and development of pulmonary fibrosis and provided a novel target for clinical intervention.

CYP7A1 Gene Induction via SHP-Dependent or Independent Mechanisms can Increase the Risk of Drug-Induced Liver Injury Independently or in Synergy with BSEP Inhibition

Drug-induced liver injury (DILI) is a frequent cause of clinical trial failures during drug development. While inhibiting bile salt export pump (BSEP) is a well-documented DILI mechanism, interference with genes related to bile acid (BA) metabolism and transport can further complicate DILI development. Here, the effects of twenty-eight compounds on genes associated with BA metabolism and transport were evaluated, including those with discontinued development or use, boxed warnings, and clean labels for DILI. The study also included rifampicin and omeprazole, pregnane X receptor and aryl hydrocarbon receptor ligands, and four mitogen-activated protein kinase kinase (MEK1/2) inhibitors. BSEP inhibitors with more severe DILI, notably pazopanib and CP-724714, significantly upregulated the expression of 7 alpha-hydroxylase (CYP7A1), independent of small heterodimer partner (SHP) expression. CYP7A1 expression was marginally induced by omeprazole. In contrast, its expression was suppressed by mometasone (10-fold), vinblastine (18-fold), hexachlorophene (2-fold), bosentan (2.1-fold), and rifampin (2-fold). All four MEK1/2 inhibitors that show clinical DILI were not potent BSEP inhibitors but significantly induced CYP7A1 expression, accompanied by a significant SHP gene suppression. Sulfotransferase 2A1 and BSEP were marginally upregulated, but no other genes were altered by the drugs tested. Protein levels of CYP7A1 were increased with the treatment of CYP7A1 inducers and decreased with obeticholic acid, an farnesoid X receptor ligand. CYP7A1 inducers significantly increased bile acid (BA) production in hepatocytes, indicating the overall regulatory effects of BA metabolism. This study demonstrates that CYP7A1 induction via various mechanisms can pose a risk for DILI, independently or in synergy with BSEP inhibition, and it should be evaluated early in drug discovery. SIGNIFICANCE STATEMENT: Kinase inhibitors, pazopanib and CP-724714, inhibit BSEP and induce CYP7A1 expression independent of small heterodimer partner (SHP) expression, leading to increased bile acid (BA) production and demonstrating clinically elevated drug-induced liver toxicity. MEK1/2 inhibitors that show BSEP-independent drug-induced liver injury (DILI) induced the CYP7A1 gene accompanied by SHP suppression. CYP7A1 induction via SHP-dependent or independent mechanisms can pose a risk for DILI, independently or in synergy with BSEP inhibition. Monitoring BA production in hepatocytes can reliably detect the total effects of BA-related gene regulation for de-risking.

Lysophosphatidic acid receptor 1 inhibition: a potential treatment target for pulmonary fibrosis

Lysophosphatidic acid (LPA)-mediated activation of LPA receptor 1 (LPAR1) contributes to the pathophysiology of fibrotic diseases such as idiopathic pulmonary fibrosis (IPF) and systemic sclerosis (SSc). These diseases are associated with high morbidity and mortality despite current treatment options. The LPA-producing enzyme autotaxin (ATX) and LPAR1 activation contribute to inflammation and mechanisms underlying fibrosis in preclinical fibrotic models. Additionally, elevated levels of LPA have been detected in bronchoalveolar lavage fluid from patients with IPF and in serum from patients with SSc. Thus, ATX and LPAR1 have gained considerable interest as pharmaceutical targets to combat fibrotic disease and inhibitors of these targets have been investigated in clinical trials for IPF and SSc. The goals of this review are to summarise the current literature on ATX and LPAR1 signalling in pulmonary fibrosis and to help differentiate the novel inhibitors in development. The mechanisms of action of ATX and LPAR1 inhibitors are described and preclinical studies and clinical trials of these agents are outlined. Because of their contribution to numerous physiologic events underlying fibrotic disease, ATX and LPAR1 inhibition presents a promising therapeutic strategy for IPF, SSc and other fibrotic diseases that may fulfil unmet needs of the current standard of care.

Discovery of a Novel Orally Active, Selective LPA Receptor Type 1 Antagonist, 4-(4-(2-Isopropylphenyl)-4-((2-methoxy-4-methylphenyl)carbamoyl)piperidin-1-yl)-4-oxobutanoic Acid, with a Distinct Molecular Scaffold

Lysophosphatidic acid receptor 1 (LPAR1) antagonists show promise as potentially novel antifibrotic treatments. In a human LPAR1 β-arrestin recruitment-based high-throughput screening campaign, we identified urea 19 as a hit with a LPAR1 IC50 value of 5.0 μM. Hit-to-lead activities revealed that one of the urea nitrogen atoms can be replaced by carbon and establish the corresponding phenylacetic amide as a lead structure for further optimization. Medicinal chemistry efforts led to the discovery of piperidine 18 as a potent and selective LPAR1 antagonist with oral activity in a mouse model of LPA-induced skin vascular leakage. The molecular scaffold of 18 shares no obvious structural similarity with any other LPAR1 antagonist disclosed so far.

Discovery of the Novel, Orally Active, and Selective LPA1 Receptor Antagonist ACT-1016-0707 as a Preclinical Candidate for the Treatment of Fibrotic Diseases

Piperidine 3 is a potent and selective lysophosphatidic acid receptor subtype 1 receptor (LPAR1) antagonist that has shown efficacy in a skin vascular leakage target engagement model in mice. However, compound 3 has very high human plasma protein binding and high clearance in rats, which could significantly hamper its clinical development. Continued lead optimization led to the potent, less protein bound, metabolically stable, and orally active azetidine 17. Rat pharmacokinetics (PK) studies revealed that 17 accumulated in the liver. In vitro studies indicated that 17 is an organic anion co-transporting polypeptide 1B1 (OATP1B1) substrate. Although analogue 24 was no longer a substrate of OATP1B1, PK studies suggested that the compound undergoes enterohepatic recirculation. Replacing the carboxylic acidic side chain by a non-acidic sulfamide moiety and further fine-tuning of the scaffold yielded the potent, orally active LPAR1 antagonist 49, which was selected for preclinical development for the treatment of fibrotic diseases.

Experimental autotaxin inhibitors for the treatment of idiopathic pulmonary fibrosis

INTRODUCTION

Idiopathic Pulmonary Fibrosis (IPF) is a progressive, irreversible, and fatal lung disease with unmet medical needs. Autotaxin (ATX) is an extracellular enzyme involved in the generation of lysophosphatidic acid (LPA). Preclinical and clinical data have suggested the ATX-LPAR signaling axis plays an important role in the pathogenesis and the progression of IPF.

AREAS COVERED

The aim of this review is to provide an update on the available evidence on autotaxin inhibitors in IPF and further details on the ongoing clinical studies involving these molecules.

EXPERT OPINION

The development of autotaxin inhibitors as a potential therapy for idiopathic pulmonary fibrosis has gained attention due to evidence of their involvement in the disease. Preclinical and early-phase clinical studies have explored these inhibitors' efficacy and safety, offering a novel approach in treating this disease. Combining autotaxin inhibitors with existing anti-fibrotic agents is considered for enhanced therapeutic effects. Large phase III trials assessed Ziritaxestat but yielded disappointing results, highlighting the importance of long-term observation and clinical outcomes in clinical research. Patient stratification and personalized medicine are crucial, as pulmonary fibrosis is a heterogeneous disease. Ongoing research and collaboration are essential for this advancement.

Ectopic and visceral fat deposition in aging, obesity, and idiopathic pulmonary fibrosis: an interconnected role

Idiopathic pulmonary fibrosis (IPF) is considered an age-related disease. Age-related changes, along with other factors such as obesity, hormonal imbalances, and various metabolic disorders, lead to ectopic fat deposition (EFD). This accumulation of fat outside of its normal storage sites is associated with detrimental effects such as lipotoxicity, oxidative stress, inflammation, and insulin resistance. This narrative review provides an overview of the connection between ectopic and visceral fat deposition in aging, obesity, and IPF. It also elucidates the mechanism by which ectopic fat deposition in the airways and lungs, pericardium, skeletal muscles, and pancreas contributes to lung injury and fibrosis in patients with IPF, directly or indirectly. Moreover, the review discusses the impact of EFD on the severity of the disease, quality of life, presence of comorbidities, and overall prognosis in IPF patients. The review provides detailed information on recent research regarding representative lipid-lowering drugs, hypoglycemic drugs, and lipid-targeting drugs in animal experiments and clinical studies. This may offer new therapeutic directions for patients with IPF.

Emerging opportunities to treat idiopathic pulmonary fibrosis: Design, discovery, and optimizations of small-molecule drugs targeting fibrogenic pathways

Idiopathic pulmonary fibrosis (IPF) is the most common fibrotic form of idiopathic diffuse lung disease. Due to limited treatment options, IPF patients suffer from poor survival. About ten years ago, Pirfenidone (Shionogi, 2008; InterMune, 2011) and Nintedanib (Boehringer Ingelheim, 2014) were approved, greatly changing the direction of IPF drug design. However, limited efficacy and side effects indicate that neither can reverse the process of IPF. With insights into the occurrence of IPF, novel targets and agents have been proposed, which have fundamentally changed the treatment of IPF. With the next-generation agents, targeting pro-fibrotic pathways in the epithelial-injury model offers a promising approach. Besides, several next-generation IPF drugs have entered phase II/III clinical trials with encouraging results. Due to the rising IPF treatment requirements, there is an urgent need to completely summarize the mechanisms, targets, problems, and drug design strategies over the past ten years. In this review, we summarize known mechanisms, target types, drug design, and novel technologies of IPF drug discovery, aiming to provide insights into the future development and clinical application of next-generation IPF drugs.

In vitro pharmacological characterization of standard and new lysophosphatidic acid receptor antagonists using dynamic mass redistribution assay

Lysophosphatidic acid (LPA) is a bioactive phospholipid that acts as an agonist of six G protein-coupled receptors named LPA receptors (LPA1-6). LPA elicits diverse intracellular events and modulates several biological functions, including cell proliferation, migration, and invasion. Overactivation of the LPA-LPA receptor system is reported to be involved in several pathologies, including cancer, neuropathic pain, fibrotic diseases, atherosclerosis, and type 2 diabetes. Thus, LPA receptor modulators may be clinically relevant in numerous diseases, making the identification and pharmacodynamic characterization of new LPA receptor ligands of strong interest. In the present work, label-free dynamic mass redistribution (DMR) assay has been used to evaluate the pharmacological activity of some LPA1 and LPA2 standard antagonists at the recombinant human LPA1 and LPA2 receptors. These results are compared to those obtained in parallel experiments with the calcium mobilization assay. Additionally, the same experimental protocol has been used for the pharmacological characterization of the new compound CHI. KI 16425, RO 6842262, and BMS-986020 behaved as LPA1 inverse agonists in DMR experiments and as LPA1 antagonists in calcium mobilization assays. Amgen compound 35 behaved as an LPA2 antagonist, while Merck compound 20 from WO2012028243 was detected as an LPA2 inverse agonist using the DMR test. Of note, for all the compounds, similar potency values were estimated by DMR and calcium assay. The new compound CHI was found to be an LPA1 inverse agonist, but with potency lower than that of the standard compounds. In conclusion, we have demonstrated that DMR assay can be successfully used to characterize LPA1 and LPA2 ligands. Compared to the classical calcium mobilization assay, DMR offers some advantages, in particular allowing the identification of inverse agonists. Finally, in the frame of this study, a new LPA1 inverse agonist has been identified.

Discovery of Chemical Scaffolds as Lysophosphatidic Acid Receptor 1 Antagonists: Virtual Screening, In Vitro Validation, and Molecular Dynamics Analysis

Lysophosphatidic acid receptor 1 (LPAR1) is an emerging therapeutic target for numerous human diseases including fibrosis. However, the limited number of available core structures of LPAR1 antagonists has prompted the need for novel chemical templates. In this study, we conducted a high-throughput virtual screening to discover potential new scaffolds. We tested three existing crystal structures alongside an AlphaFold model to evaluate their suitability in structure-based virtual screening, finding that the crystal structures show superior performance compared with the predictive model. Furthermore, we also found that enhancing the precision in the screening process did not necessarily improve the enrichment of hits. From the screening campaign, we identified five structures that were validated using an LPAR1-dependent calcium flux assay. To gain a deeper insight into the protein-ligand interaction, we extensively analyzed the binding modes of these compounds using in silico techniques, laying the groundwork for the discovery of novel LPAR1 antagonists.

Inhibition of LPA-LPAR1 and VEGF-VEGFR2 Signaling in IPF Treatment

Due to the complex mechanism and limited treatments available for pulmonary fibrosis, the development of targeted drugs or inhibitors based on their molecular mechanisms remains an important strategy for prevention and treatment. In this paper, the downstream signaling pathways mediated by VEGFR and LPAR1 in pulmonary cells and the role of these pathways in pulmonary fibrosis, as well as the current status of drug research on the targets of LPAR1 and VEGFR2, are described. The mechanism by which these two pathways regulate vascular leakage and collagen deposition leading to the development of pulmonary fibrosis are analyzed, and the mutual promotion of the two pathways is discussed. Here we propose the development of drugs that simultaneously target LPAR1 and VEGFR2, and discuss the important considerations in targeting and safety.

New therapeutic approaches against pulmonary fibrosis

Pulmonary fibrosis is the end-stage change of a large class of lung diseases characterized by the proliferation of fibroblasts and the accumulation of a large amount of extracellular matrix, accompanied by inflammatory damage and tissue structure destruction, which also shows the normal alveolar tissue is damaged and then abnormally repaired resulting in structural abnormalities (scarring). Pulmonary fibrosis has a serious impact on the respiratory function of the human body, and the clinical manifestation is progressive dyspnea. The incidence of pulmonary fibrosis-related diseases is increasing year by year, and no curative drugs have appeared so far. Nevertheless, research on pulmonary fibrosis have also increased in recent years, but there are no breakthrough results. Pathological changes of pulmonary fibrosis appear in the lungs of patients with coronavirus disease 2019 (COVID-19) that have not yet ended, and whether to improve the condition of patients with COVID-19 by means of the anti-fibrosis therapy, which are the questions we need to address now. This review systematically sheds light on the current state of research on fibrosis from multiple perspectives, hoping to provide some references for design and optimization of subsequent drugs and the selection of anti-fibrosis treatment plans and strategies.

Base-Modulated 1,3-Regio- and Stereoselective Carboboration of Cyclohexenes

While chain-walking stimulates wide interest in both polymerization and organic synthesis, site- and stereoselective control of chain-walking on rings is still a challenging task in the realm of organometallic catalysis. Inspired by a controllable chain-walking on cyclohexane rings in olefin polymerization, we have developed a set of chain-walking carboborations of cyclohexenes based on nickel catalysis. Different from the 1,4-trans-selectivity disclosed in polymer science, a high level of 1,3-regio- and cis-stereoselectivity is obtained in our reactions. Mechanistically, we discovery that the base affects the reduction ability of B2 pin2 and different bases lead to different catalytic cycles and different regioselective products (1,2- Vs 1,3-addition). This study provides a concise and modular method for the synthesis of 1,3-disubstituted cyclohexylboron compounds. The incorporation of a readily modifiable boronate group greatly enhances the value of this method, the synthetic potential of which was highlighted by the synthesis of a series of high-valued commercial chemicals and pharmaceutically interesting molecules.

An Analysis of Successful Hit-to-Clinical Candidate Pairs

An analysis of 156 published clinical candidates from the Journal of Medicinal Chemistry between 2018 and 2021 was conducted to identify lead generation strategies most frequently employed leading to drug candidates. As in a previous publication, the most frequent lead generation strategies resulting in clinical candidates were from known compounds (59%) followed by random screening approaches (21%). The remainder of the approaches included directed screening, fragment screening, DNA-encoded library screening (DEL), and virtual screening. An analysis of similarity was also conducted based on Tanimoto-MCS and revealed most clinical candidates were distant from their original hits; however, most shared a key pharmacophore that translated from hit-to-clinical candidate. An examination of frequency of oxygen, nitrogen, fluorine, chlorine, and sulfur incorporation in clinical candidates was also conducted. The three most similar and least similar hit-to-clinical pairs from random screening were examined to provide perspective on changes that occur that lead to successful clinical candidates.

Cellular and Molecular Control of Lipid Metabolism in Idiopathic Pulmonary Fibrosis: Clinical Application of the Lysophosphatidic Acid Pathway

Idiopathic pulmonary fibrosis (IPF) is a representative disease that causes fibrosis of the lungs. Its pathogenesis is thought to be characterized by sustained injury to alveolar epithelial cells and the resultant abnormal tissue repair, but it has not been fully elucidated. IPF is currently difficult to cure and is known to follow a chronic progressive course, with the patient's survival period estimated at about three years. The disease occasionally exacerbates acutely, leading to a fatal outcome. In recent years, it has become evident that lipid metabolism is involved in the fibrosis of lungs, and various reports have been made at the cellular level as well as at the organic level. The balance among eicosanoids, sphingolipids, and lipid composition has been reported to be involved in fibrosis, with particularly close attention being paid to a bioactive lipid "lysophosphatidic acid (LPA)" and its pathway. LPA signals are found in a wide variety of cells, including alveolar epithelial cells, vascular endothelial cells, and fibroblasts, and have been reported to intensify pulmonary fibrosis via LPA receptors. For instance, in alveolar epithelial cells, LPA signals reportedly induce mitochondrial dysfunction, leading to epithelial damage, or induce the transcription of profibrotic cytokines. Based on these mechanisms, LPA receptor inhibitors and the metabolic enzymes involved in LPA formation are now considered targets for developing novel means of IPF treatment. Advances in basic research on the relationships between fibrosis and lipid metabolism are opening the path to new therapies targeting lipid metabolism in the treatment of IPF.

Targeting the LPA1 signalling pathway for fibrosis therapy: a patent review (2010-present)

INTRODUCTION

Fibrosis is a disease that damages organs and even causes death. Because of the complicated pathogenesis, the development of drugs for fibrosis is challenging. In the lysophosphatidic acid receptor type 1 (LPA1) signalling pathway, LPA1 and its downstream Rho-associated coiled-coil forming protein kinase (ROCK) are related to the process of fibrosis. Targeting LPA1 signalling pathway is a potential strategy for the treatment of fibrosis.

AREA COVERED

This review describes the process of fibrosis mediated by the LPA1 signalling pathway and then summarizes LPA1 antagonist patents reported since 2010 and ROCK inhibitor patents since 2017 according to their scaffolds based on the Cortellis Drug Discovery Intelligence database. Information on LPA1 antagonists entering clinical trials is integrated.

EXPERT OPINION

Over the past decade, a large number of antagonists targeting the LPA1 signalling pathway have been patented for fibrosis therapy. A limited number of compounds have entered clinical trials. Different companies and research groups have used different scaffolds when designing compounds for fibrosis therapy. Therefore, LPA1 and ROCK are competitive targets for the development of new therapies for fibrosis to provide a potential treatment method for fibrosis in the future.

Discovery of Aryloxyphenyl-Heptapeptide Hybrids as Potent and Selective Matrix Metalloproteinase-2 Inhibitors for the Treatment of Idiopathic Pulmonary Fibrosis

Matrix metalloproteinase-2 (MMP2) is a zinc-dependent endopeptidase that plays important roles in the degradation of extracellular matrix proteins. MMP2 is considered to be an attractive target for the treatment of various diseases such as cancer, arthritis, and fibrosis. In this study, we have developed a novel class of MMP2-selective inhibitors by hybridizing the peptide that binds to a zinc ion and S2-S5 pockets with small molecules that bind to the S1' pocket. Structural modifications based on X-ray crystallography revealed that the introduction of 2,4-diaminobutanoic acid (Dab) at position 4 dramatically enhanced MMP2 selectivity by forming an electrostatic interaction with Glu130. After improving the metabolic and chemical stability, TP0556351 (9) was identified. It exhibited potent MMP2 inhibitory activity (IC₅₀ = 0.20 nM) and extremely high selectivity. It suppressed the accumulation of collagen in a bleomycin-induced idiopathic pulmonary fibrosis model in mice, demonstrating the efficacy of MMP2-selective inhibitors for fibrosis.

Structure dependence and species sensitivity of in vivo hepatobiliary toxicity with lysophosphatidic acid receptor 1 (LPA1) antagonists

BMS-986020, BMS-986234 and BMS-986278, are three lysophosphatidic acid receptor 1 (LPA₁) antagonists that were or are being investigated for treatment of idiopathic pulmonary fibrosis (IPF). Hepatobiliary toxicity (elevated serum AST, ALT, and ALP, plasma bile acids [BAs], and cholecystitis) was observed in a Phase 2 clinical trial with BMS-986020, and development was discontinued. In dogs and rats, the species used for the pivotal toxicology studies, there was no evidence of hepatobiliary toxicity in the dog while findings in the rat were limited to increased plasma BAs levels (6.1× control), ALT (2.9×) and bilirubin (3.4×) with no histopathologic correlates. Since neither rats nor dogs predicted clinical toxicity, follow-up studies in cynomolgus monkeys revealed hepatobiliary toxicity that included increased ALT (2.0× control) and GLDH (4.9×), bile duct hyperplasia, cholangitis, cholestasis, and cholecystitis at clinically relevant BMS-986020 exposures with no changes in plasma or liver BAs. This confirmed monkey as a relevant species for identifying hepatobiliary toxicity with BMS-986020. In order to assess whether the toxicity was compound-specific or related to LPA₁ antagonism, two structurally distinct LPA₁ antagonists (BMS-986234 and BMS-986278), were evaluated in rat and monkey. There were no clinical or anatomic pathology changes indicative of hepatobiliary toxicity. Mixed effects on plasma bile acids in both rat and monkey has made this biomarker not a useful predictor of the hepatobiliary toxicity. In conclusion, the nonclinical data indicate the hepatobiliary toxicity observed clinically and in monkeys administered BMS-986020 is compound specific and not mediated via antagonism of LPA₁.