Nrf2 Activation Promotes Lung Cancer Metastasis by Inhibiting the Degradation of Bach1.

Approximately 30% of human lung cancers acquire mutations in either Keap1 or Nfe2l2, resulting in the stabilization of Nrf2, the Nfe2l2 gene product, which controls oxidative homeostasis. Here, we show that heme triggers the degradation of Bach1, a pro-metastatic transcription factor, by promoting its interaction with the ubiquitin ligase Fbxo22. Nrf2 accumulation in lung cancers causes the stabilization of Bach1 by inducing Ho1, the enzyme catabolizing heme. In mouse models of lung cancers, loss of Keap1 or Fbxo22 induces metastasis in a Bach1-dependent manner. Pharmacological inhibition of Ho1 suppresses metastasis in a Fbxo22-dependent manner. Human metastatic lung cancer display high levels of Ho1 and Bach1. Bach1 transcriptional signature is associated with poor survival and metastasis in lung cancer patients. We propose that Nrf2 activates a metastatic program by inhibiting the heme- and Fbxo22-mediated degradation of Bach1, and that Ho1 inhibitors represent an effective therapeutic strategy to prevent lung cancer metastasis.

An open-source drug discovery platform enables ultra-large virtual screens.

On average, an approved drug currently costs US$2-3 billion and takes more than 10 years to develop1. In part, this is due to expensive and time-consuming wet-laboratory experiments, poor initial hit compounds and the high attrition rates in the (pre-)clinical phases. Structure-based virtual screening has the potential to mitigate these problems. With structure-based virtual screening, the quality of the hits improves with the number of compounds screened2. However, despite the fact that large databases of compounds exist, the ability to carry out large-scale structure-based virtual screening on computer clusters in an accessible, efficient and flexible manner has remained difficult. Here we describe VirtualFlow, a highly automated and versatile open-source platform with perfect scaling behaviour that is able to prepare and efficiently screen ultra-large libraries of compounds. VirtualFlow is able to use a variety of the most powerful docking programs. Using VirtualFlow, we prepared one of the largest and freely available ready-to-dock ligand libraries, with more than 1.4 billion commercially available molecules. To demonstrate the power of VirtualFlow, we screened more than 1 billion compounds and identified a set of structurally diverse molecules that bind to KEAP1 with submicromolar affinity. One of the lead inhibitors (iKeap1) engages KEAP1 with nanomolar affinity (dissociation constant (Kd) = 114 nM) and disrupts the interaction between KEAP1 and the transcription factor NRF2. This illustrates the potential of VirtualFlow to access vast regions of the chemical space and identify molecules that bind with high affinity to target proteins.

Combinatorial CRISPR-Cas9 Metabolic Screens Reveal Critical Redox Control Points Dependent on the KEAP1-NRF2 Regulatory Axis.

The metabolic pathways fueling tumor growth have been well characterized, but the specific impact of transforming events on network topology and enzyme essentiality remains poorly understood. To this end, we performed combinatorial CRISPR-Cas9 screens on a set of 51 carbohydrate metabolism genes that represent glycolysis and the pentose phosphate pathway (PPP). This high-throughput methodology enabled systems-level interrogation of metabolic gene dispensability, interactions, and compensation across multiple cell types. The metabolic impact of specific combinatorial knockouts was validated using 13C and 2H isotope tracing, and these assays together revealed key nodes controlling redox homeostasis along the KEAP-NRF2 signaling axis. Specifically, targeting KEAP1 in combination with oxidative PPP genes mitigated the deleterious effects of these knockouts on growth rates. These results demonstrate how our integrated framework, combining genetic, transcriptomic, and flux measurements, can improve elucidation of metabolic network alterations and guide precision targeting of metabolic vulnerabilities based on tumor genetics.

KEAP1-NRF2 protein-protein interaction inhibitors: Design, pharmacological properties and therapeutic potential.

The transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) is considered the master regulator of the phase II antioxidant response. It controls a plethora of cytoprotective genes related to oxidative stress, inflammation, and protein homeostasis, among other processes. Activation of these pathways has been described in numerous pathologies including cancer, cardiovascular, respiratory, renal, digestive, metabolic, autoimmune, and neurodegenerative diseases. Considering the increasing interest of discovering novel NRF2 activators due to its clinical application, initial efforts were devoted to the development of electrophilic drugs able to induce NRF2 nuclear accumulation by targeting its natural repressor protein Kelch-like ECH-associated protein 1 (KEAP1) through covalent modifications on cysteine residues. However, off-target effects of these drugs prompted the development of an innovative strategy, the search of KEAP1-NRF2 protein-protein interaction (PPI) inhibitors. These innovative activators are proposed to target NRF2 in a more selective way, leading to potentially improved drugs with the application for a variety of diseases that are currently under investigation. In this review, we summarize known KEAP1-NRF2 PPI inhibitors to date and the bases of their design highlighting the most important features of their respective interactions. We also discuss the preclinical pharmacological properties described for the most promising compounds.

Bright and stable luminescent probes for target engagement profiling in live cells.

The pace of progress in biomedical research directly depends on techniques that enable the quantitative interrogation of interactions between proteins and other biopolymers, or with their small-molecule ligands. Time-resolved Förster resonance energy transfer (TR-FRET) assay platforms offer high sensitivity and specificity. However, the paucity of accessible and biocompatible luminescent lanthanide complexes, which are essential reagents for TR-FRET-based approaches, and their poor cellular permeability have limited broader adaptation of TR-FRET beyond homogeneous and extracellular assay applications. Here, we report the development of CoraFluors, a new class of macrotricyclic terbium complexes, which are synthetically readily accessible, stable in biological media and exhibit photophysical and physicochemical properties that are desirable for biological studies. We validate the performance of CoraFluors in cell-free systems, identify cell-permeable analogs and demonstrate their utility in the quantitative domain-selective characterization of Keap1 ligands, as well as in isoform-selective target engagement profiling of HDAC1 inhibitors in live cells.

Identification of potential andrographolide-based drug candidate against Keap1-Nrf2 pathway through rigorous cheminformatics screening.

The Keap1-Nrf2 [Kelch-like ECH-associated protein-1-Nuclear factor erythroid-2-related factor-2] regulatory pathway plays a vital role in the protection of cells by regulating transcription of antioxidant and detoxification genes. Andrographolide (AGP) regulates the Keap1-Nrf2 pathway by inhibiting the Keap1 protein. To identify a more potent AGP analog as a therapeutic agent against Keap1 protein, in this work, cheminformatics analysis of 237 AGP analogs was carried out. Amongst these, five AGP analogs were screened through virtual screening followed by their molecular docking analysis against Keap1 protein, which revealed greater binding affinities (binding energy = - 4.15 to - 5.59 kcal/mol) for the shortlisted AGP analogs compared to AGP (binding energy = - 4.02 kcal/mol). Pharmacophore mapping indicated 14 spatial features, including 3 hydrogen bond acceptors and 11 hydrophobic, while ADME analysis established the potential of all five analogs as orally-active drug-like candidates based on Lipinski's rule of five. We also examined the chemical reactivity of AGP and the shortlisted AGP analogs using DFT analysis, which revealed that except for one analog (AGP_A2) all are more chemically reactive than AGP. Further, molecular dynamics simulation analysis and MM/GBSA evidenced that AGP_A1 (PubchemID-123361152), AGP_A3 (PubchemID-58209855) and AGP_A4 (PubchemID-101362374) are the best drug like candidates compared to AGP and have greater potential to activate the Keap1-Nrf2 pathway by inhibiting the Keap1 protein.

Cadmium exposure promotes thyroid pyroptosis and endocrine dysfunction by inhibiting Nrf2/Keap1 signaling.

Cadmium (Cd) is a ubiquitous toxic metal and environmental pollutant. Increasing studies have shown that Cd exposure increases the incidence of various endocrine system diseases, including thyrotoxicity reflected by thyroid structural damage and endocrine toxicity. However, the observed outcomes are complex and conflicting, leading to the mechanism of Cd-induced thyrotoxicity remaining obscure. In this study, 4-week-old male C57BL/6 mice were given 2 or 7 mg/kg Cadmium Chloride (CdCl2) intragastrically for 4 and 8 weeks, and the Cd-mediated thyrotoxicity was evaluated by determining alterations in thyroid structure and endocrine function, and alterations of oxidant stress, apoptosis, and pyroptosis. Our data showed that Cd exposure could reduce body weight and induce thyrotoxicity by impairing thyroid follicular morphology and endocrine function, accompanied by elevated oxidative stress and apoptosis, macrophage infiltration, and inflammatory cytokine secretion. Importantly, Cd significantly promoted thyroid follicular cell pyroptosis by increasing Nlrp3, Asc, Caspase-1, Gsdmd, IL-1ß, and IL-18 expression. Mechanistical analysis suggested that Cd treatment could inhibit antioxidant pathway by downregulating antioxidant response protein, Nrf2, and upregulating its negative feedback regulator, Keap1. Collectively, our in vivo findings suggest that Cd exposure could facilitate thyroid follicular cell pyroptosis by inhibiting Nrf2/Keap1 signaling, thereby disrupting thyroid tissue structure and endocrine function, which offers novel insights into the Cd-mediated detrimental consequences on thyroid homeostasis.

iKeap1 activates Nrf2 signaling to protect myocardial cells from oxygen glucose deprivation/re-oxygenation-induced oxidative injury.

Nuclear factor E2-related factor 2 (Nrf2) activation could efficiently protect myocardial cells from oxygen glucose deprivation/re-oxygenation (OGDR). An ultra-large structure-based virtual screening has discovered iKeap1 as a novel, direct and potent Keap1 inhibitor. Here we found that iKeap1 efficiently activated Nrf2 signaling in H9c2 myocardial cells and primary murine myocardiocytes. iKeap1 induced Keap1-Nrf2 disassociation, cytosol Nrf2 protein stabilization and nuclear translocation. The antioxidant response element (ARE) activity and expression of Nrf2 cascade genes (HO1, NQO1 and GCLC) were increased in iKeap1-treated myocardial cells. In H9c2 cells and murine myocardiocytes, iKeap1 potently inhibited OGDR-induced oxidative injury by inhibiting reactive oxygen species (ROS) production, mitochondrial depolarization, lipid peroxidation and DNA damage. In addition, OGDR-induced myocardial cell death and apoptosis were largely ameliorated after pretreatment with the novel Keap1 inhibitor. Significantly, in H9c2 cells iKeap1-induced myocardial cytoprotection against OGDR was abolished with Nrf2 silencing or knockout (using CRISPR/Cas9 method). Moreover, CRISPR/Cas9-induced Keap1 knockout led to constitutive activation of Nrf2 cascade and inhibited OGDR-induced oxidative injury. Importantly, iKeap1 was unable to further protect Keap1-knockout H9c2 cells from OGDR. Together, iKeap1 activated Nrf2 signaling to protect myocardial cells from OGDR-induced oxidative injury and cell death.

Direct Keap1-kelch inhibitors as potential drug candidates for oxidative stress-orchestrated diseases: A review on In silico perspective.

The recent outcry in the search for direct keap1 inhibitors requires a quicker and more effective drug discovery process which is an inherent property of the Computer Aided Drug Discovery (CADD) to bring drug candidates into the clinic for patient's use. This Keap1 (negative regulator of ARE master activator) is emerging as a therapeutic strategy to combat oxidative stress-orchestrated diseases. The advances in computer algorithm and compound databases require that we highlight the functionalities that this technology possesses that can be exploited to target Keap1-Nrf2 PPI. Therefore, in this review, we uncover the in silico approaches that had been exploited towards the identification of keap1 inhibition in the light of appropriate fitting with relevant amino acid residues, we found 3 and 16 other compounds that perfectly fit keap1 kelch pocket/domain. Our goal is to harness the parameters that could orchestrate keap1 surface druggability by utilizing hotspot regions for virtual fragment screening and identification of hotspot residues.

Optimization of 1,4-bis(arylsulfonamido)naphthalene-N,N'-diacetic acids as inhibitors of Keap1-Nrf2 protein-protein interaction to suppress neuroinflammation.

The protein-protein interaction (PPI) between kelch-like ECH-associated protein 1 (Keap1) and nuclear factor erythroid 2-related factor 2 (Nrf2) is recognized as a promising target for the prevention and treatment of oxidative stress-related inflammatory diseases. Herein, a series of novel 1,4-bis(arylsulfonamido)naphthalene-N,N'-diacetic acid analogs (7p-t and 8c) were designed to further explore the structure-activity relationships of the series. Their activities were measured first with a fluorescence polarization (FP) assay and more potent compounds were further evaluated using a more sensitive time-resolved fluorescence energy transfer (TR-FRET) assay, demonstrating IC50 values between 7.2 and 31.3 nM. In cytotoxicity studies, the naphthalene derivatives did not show noticeable toxicity to human HepG2-C8 and mouse brain BV-2 microglia cells. Among them, compound 7q bearing oxygen-containing fused rings was shown to significantly stimulate the cellular Nrf2 signaling pathway, including activation of antioxidant response element (ARE)-controlled expression of Nrf2 target genes and proteins. More importantly, 7q suppressed up-regulation of several pro-inflammatory cytokines in lipopolysaccharide (LPS)-challenged BV-2 microglial cells, representing a potential therapeutic application for controlling neuroinflammatory disorders.

Swimming training mitigates the sex-specific hepatic disruption caused by a high-calorie diet: The putative modulation of Nrf2/Keap-1 pathway in male mice.

This study investigated whether swimming protocol induces adaptations to sex-specific oxidative stress and Nrf2/Keap-1 pathway in the liver of mice fed a high-calorie diet (HCD) during the early life period. Male and female Swiss mice were fed a standard or high-calorie (enriched with 20% lard and 20% corn syrup) diets, and the trained mice were subjected to a swimming protocol (5 days/week) from 21st to 49th postnatal days. Males fed a HCD had more pronounced alterations in all parameters evaluated than females. Although there was no increase in body weight, the fat deposition was higher in male mice exposed to diet. The intake of HCD induced dyslipidemia mainly in males. In a sex-dependent manner, the hepatic markers of oxidative damage, antioxidant defences, and a sensitive sulfhydryl protein were altered in mice fed a HCD. Swimming counteracted dyslipidemia, hepatic oxidative stress, and the Nrf2/Keap-1 signalling downregulation, in a sex-dependent manner, in mice exposed to a HCD. These findings demonstrate that a non-pharmacological therapy, swimming protocol, contributed to adaptations of sex-specific hepatic oxidative stress and Nrf2/Keap-1 regulation in male mice fed a HCD.

The potential role of Keap1-Nrf2 pathway in the pathogenesis of Alzheimer's disease, type 2 diabetes, and type 2 diabetes-related Alzheimer's disease.

Kelch-like ECH associated-protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway is thought to be the key regulatory process defensing oxidative stress in multiple organs. Type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD) are both serious global health problems with high prevalence. A growing number of literatures have suggested a possible link between Keap1-Nrf2 signaling pathway and the pathological changes of T2DM, AD as well as T2DM-related AD. The current review mainly discusses how the damaged Keap1-Nrf2 signaling pathway leads to dysregulated redox molecular signaling, which may contribute to the pathogenesis of AD and T2DM-related cognitive dysfunction, as well as some compounds targeting this pathway. The further exploration of the mechanisms of this pathway could provide novel therapeutic strategies to improve cognitive function, through restoration of expression or translocation of Nrf2 and scavenging excessive free radicals.

Management of COVID-19-induced cytokine storm by Keap1-Nrf2 system: a review.

The natural pathway of antioxidant production is mediated through Kelch-like erythroid cell-derived protein with Cap and collar homology [ECH]-associated protein 1 (Keap1)-Nuclear factor erythroid 2-related factor 2 (Nrf2) system. Keap1 maintains a low level of Nrf2 by holding it in its protein complex. Also, Keap1 facilitates the degradation of Nrf2 by ubiquitination. In other words, Keap1 is a down-regulator of Nrf2. To boost the production of biological antioxidants, Keap1 has to be inhibited and Nrf2 has to be released. Liberated Nrf2 is in an unbound state, so it travels to the nucleus to stimulate the antioxidant response element (ARE) present on the antioxidant genes. AREs activate biosynthesis of biological antioxidants through genes responsible for the production of antioxidants. In some cases of coronavirus disease 2019 (COVID-19), there is an enormous release of cytokines. The antioxidant defense mechanism in the body helps in counteracting symptoms induced by the cytokine storm in COVID-19. So, boosting the production of antioxidants is highly desirable in such a condition. In this review article, we have compiled the role of Keap1-Nrf2 system in antioxidant production. We further propose its potential therapeutic use in managing cytokine storm in COVID-19.

The Nrf2 activator MIND4-17 protects retinal ganglion cells from high glucose-induced oxidative injury.

Diabetic retinopathy (DR) is a leading cause of acquired blindness among adults. High glucose (HG) induces oxidative injury and apoptosis in retinal ganglion cells (RGCs), serving as a primary pathological mechanism of DR. MIND4-17 activates nuclear-factor-E2-related factor 2 (Nrf2) signaling via modifying one cysteine (C151) residue of Kelch-like ECH-associated protein 1 (Keap1). The current study tested its effect in HG-treated primary murine RGCs. We show that MIND4-17 disrupted Keap1-Nrf2 association, leading to Nrf2 protein stabilization and nuclear translocation, causing subsequent expression of key Nrf2 target genes, including heme oxygenase-1 and NAD(P)H quinone oxidoreductase 1. Functional studies showed that MIND4-17 pretreatment significantly inhibited HG-induced cytotoxicity and apoptosis in primary murine RGCs. Reactive oxygen species production and oxidative injury in HG-treated murine RGCs were attenuated by MIND4-17. Nrf2 silencing (by targeted small interfering RNA) or knockout (by CRISPR/Cas9 method) abolished MIND4-17-induced RGC cytoprotection against HG. Additionally, Keap1 knockout or silencing mimicked and abolished MIND4-17-induced activity in RGCs. In vivo, MIND4-17 intravitreal injection activated Nrf2 signaling and attenuated retinal dysfunction by light damage in mice. We conclude that MIND4-17 activates Nrf2 signaling to protect murine RGCs from HG-induced oxidative injury.

Discovery of disubstituted xylylene derivatives as small molecule direct inhibitors of Keap1-Nrf2 protein-protein interaction.

The Keap1-Nrf2-ARE system represents a crucial antioxidant defense mechanism that protects cells against reactive oxygen species. Targeting Keap1-Nrf2 protein-protein interaction (PPI) has become a promising drug target for several oxidative stress-related and inflammatory diseases including pulmonary fibrosis, chronic obstructive pulmonary disorder (COPD) and cancer chemoprevention. For the development of a potential therapeutic agent, drug-like properties and potency are important considerations. In this work, we focused on the modification of 4 as a lead through a molecular dissection strategy in an effort to improve its metabolic stability, leading to the discovery of a series of new disubstituted xylylene derivatives. The preliminary SAR of 9a indicated that compound 21a containing S-methylated acetate moieties exhibited comparable potency to the lead compound 4 in a fluorescent polarization assay but with improved metabolic stability in the presence of human liver microsomes.

Optimization of linear and cyclic peptide inhibitors of KEAP1-NRF2 protein-protein interaction.

Inhibition of KEAP1-NRF2 protein-protein interaction is considered a promising strategy to selectively and effectively activate NRF2, a transcription factor which is involved in several pathologies such as Huntington's disease (HD). A library of linear peptides based on the NRF2-binding motifs was generated on the nonapeptide lead Ac-LDEETGEFL-NH2 spanning residues 76-84 of the Neh2 domain of NRF2 with the aim to replace E78, E79 and E82 with non-acidic amino acids. A deeper understanding of the features and accessibility of the T80 subpocket was also targeted by structure-based design. Approaches to improve cell permeability were investigated using both different classes of cyclic peptides and conjugation to cell-penetrating peptides. This insight will guide future design of macrocycles, peptido-mimetics and, most importantly, small neutral brain-penetrating molecules to evaluate whether NRF2 activators have utility in HD.

Direct inhibition of Keap1-Nrf2 Protein-Protein interaction as a potential therapeutic strategy for Alzheimer's disease.

The Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) pathway works as the key regulator against oxidative stress damage in many cells and organs. It has been a widely proposed therapeutic target for neurodegenerative diseases, including Alzheimer's disease (AD). This study aimed at determining the neuroprotective activity of 9 (NXPZ-2), a small-molecule compound that directly inhibits the Keap1-Nrf2 protein-protein interaction, in an amyloid beta 1-42 (Aß1-42) oligomer intracerebroventricularly (i.c.v.) injected mouse model. Behavioral tests showed that NXPZ-2 treatment dose-relatedly ameliorated learning and memory dysfunction in Aß1-42-treated mice. HE and Nissl staining showed that NXPZ-2 improved brain tissue pathological changes in AD mice by increasing neuron quantity and function. Western blot analysis of the hippocampus and cortex showed up-regulated Nrf2 in whole cell lysate, with increased nuclear translocation to increase Nrf2-targeted antioxidant enzymes (HO-1, NQO-1) and decreased p-Tau in NXPZ-2-treated mice. ELISA results showed that NXPZ-2 treatment increased serum Nrf2 and significantly decreased serum Aß1-42 levels in AD mice. Furthermore, hippocampal and cortical superoxide dismutase (SOD) and glutathione (GSH) levels increased, while malondialdehyde (MDA) levels decreased. No obvious toxicity was observed in primary cultured mouse cortical neurons and organs with NXPZ-2 treatment. No ameliorative effect was observed of NXPZ-2 in Nrf2 knockout AD mice. Collectively, our findings demonstrated that NXPZ-2 could be a promising therapeutic agent against AD, and provided the first set of experimental evidence, in a mouse model, to support Keap1-Nrf2 interaction as a validated target for the Nrf2 reactivation in AD.

A novel compound AB38b attenuates oxidative stress and ECM protein accumulation in kidneys of diabetic mice through modulation of Keap1/Nrf2 signaling.

Extracellular matrix (ECM) deposition following reactive oxygen species (ROS) overproduction has a key role in diabetic nephropathy (DN), thus, antioxidant therapy is considered as a promising strategy for treating DN. Here, we investigated the therapeutic effects of AB38b, a novel synthetic α, ß-unsaturated ketone compound, on the oxidative stress (OS) and ECM accumulation in type 2 diabetes mice, and tried to clarify the mechanisms underlying the effects in high glucose (HG, 30 mM)-treated mouse glomerular mesangial cells (GMCs). Type 2 diabetes model was established in mice with high-fat diet feeding combined with streptozocin intraperitoneal administration. The diabetic mice were then treated with AB38b (10, 20, 40 mg· kg-1· d-1, ig) or a positive control drug resveratrol (40 mg· kg-1· d-1, ig) for 8 weeks. We showed that administration of AB38b or resveratrol prevented the increases in malondialdehyde level, lactate dehydrogenase release, and laminin and type IV collagen deposition in the diabetic kidney. Simultaneously, AB38b or resveratrol markedly lowered the level of Keap1, accompanied by evident activation of Nrf2 signaling in the diabetic kidney. The underlying mechanisms of antioxidant effect of AB38b were explored in HG-treated mouse GMCs. AB38b (2.5-10 µM) or resveratrol (10 µM) significantly alleviated OS and ECM accumulation in HG-treated GMCs. Furthermore, AB38b or resveratrol treatment effectively activated Nrf2 signaling by inhibiting Keap1 expression without affecting the interaction between Keap1 and Nrf2. Besides, AB38b treatment effectively suppressed the ubiquitination of Nrf2. Taken together, this study demonstrates that AB38b ameliorates experimental DN through antioxidation and modulation of Keap1/Nrf2 signaling pathway.

ZJ01, a Small Molecule Inhibitor of the Kelch-Like ECH-Associated Protein 1-Nuclear Factor Erythroid 2-Related Factor 2 (Keap1-Nrf2) Protein-Protein Interaction, Reduces Hyperoxic Acute Lung Injury in a Mouse Model.

BACKGROUND Hyperoxic acute lung injury (ALI) is a complication of ventilation in patients with respiratory failure. Nuclear factor erythroid-2-related factor 2 (Nrf2) has an important role in ALI. Kelch-like ECH-associated protein 1 (Keap1) binds to Nrf2. ZJ01 is a small molecule inhibitor of Keap1-Nrf2 protein-protein interaction (PPI) that can reduce Keap1-induced inhibition of Nrf2. This study aimed to investigate the effects of ZJ01 and the heme oxygenase-1 (HO-1) inhibitor, zinc protoporphyrin IX (ZnPP IX), in a mouse model of hyperoxic ALI. MATERIAL AND METHODS C57BL/6J mice included five study groups: the room air+vehicle-treated group; the room air+ZJ01 group; the hyperoxia+vehicle-treated group; the hyperoxia+ZJ01 group; and the hyperoxia+ZJ01+ZnPP IX group. ZJ01, ZnPP IX, or vehicle were given 1 h after the hyperoxia challenge. The lungs from the mice were harvested at 72 h following the hyperoxia challenge. RESULTS Hyperoxia exposure for 72 h increased the activity of myeloperoxidase, the lung water content, the levels of tumor necrosis factor-alpha (TNF-alpha), and matrix metalloprotease-9 (MMP-9) in the vehicle-treated mice. ZJ01 treatment reduced hyperoxia-induced inflammation and increased the activation of Nrf2 and HO-1 compared with the vehicle-treated mice. Histology of the lungs showed that ZJ01 treatment reduced the changes of hyperoxia-induced ALI. Pretreatment with ZnPP IX reversed the beneficial effect of ZJ01. CONCLUSIONS ZJ01, a Keap1-Nrf2 PPI inhibitor, reduced hyperoxic ALI in a mouse model through the Nrf2/HO-1 pathway.

Exploiting the Indole Scaffold to Design Compounds Binding to Different Pharmacological Targets.

Several indole derivatives have been disclosed by our research groups that have been collaborating for nearly 25 years. The results of our investigations led to a variety of molecules binding selectively to different pharmacological targets, specifically the type A γ-aminobutyric acid (GABAA) chloride channel, the translocator protein (TSPO), the murine double minute 2 (MDM2) protein, the A2B adenosine receptor (A2B AR) and the Kelch-like ECH-associated protein 1 (Keap1). Herein, we describe how these works were conceived and carried out thanks to the versatility of indole nucleus to be exploited in the design and synthesis of drug-like molecules.