The discovery of inhibitors of bromodomain and extra terminal domain (BET) has achieved great progress, and at least seven inhibitors have progressed into clinical trials for the treatment of cancer or inflammatory diseases. Here, we describe the identification, optimization, and evaluation of benzo[cd]indol-2(1H)-one containing compounds as a new class of BET bromodomain inhibitors, starting from structure-based virtual screening (SBVS). Through structure-based optimization, potent compounds were obtained with significantly improved activity. The two most potent compounds bind to the BRD4 bromodomain, with Kd values of 124 and 137 nM. Selected compounds exhibited high selectivity over other non-BET subfamily members. Notably, compound 85 demonstrated a reasonable antiproliferation effect on MV4;11 leukemia cells and exhibited a good pharmacokinetic profile with high oral bioavailability (75.8%) and moderate half-life (T1/2 = 3.95 h). The resulting lead molecule 85 represents a new, potent, and selective class of BET bromodomain inhibitors for the development of therapeutics to treat cancer and inflammatory diseases.

•SBVS and LBVS were used for RORγ ligand discovery.•Tertiary amines were identified as new RORγ inverse agonists.•Structure-based optimization led to a high inhibitory activity compound.•Compound 39 displayed promising activities in all of the biochemical assays.Retinoic acid receptor-related orphan receptors (RORs) are ligand-dependent transcriptional factors and members of the nuclear receptor superfamily. RORs regulate inflammation, metabolic disorders and circadian rhythm. RORγ is a promising therapeutic drug target for treating Th17-mediated autoimmune diseases. In our study, we performed structure-based virtual screening and ligand-based virtual screening targeting the RORγ ligand-binding domain and successfully identified N-phenyl-2-(N-phenylphenylsulfonamido) acetamides as a type of RORγ inverse agonist. Among the 28 purchased compounds, C11 was confirmed to be active with micromolar IC50 values in both an AlphaScreen assay (62.58 μM) and a cell-based reporter gene assay (4.54 μM). Structure-guided optimization of the compound C11 led to the identification of compound 39, which significantly enhanced RORγ inhibition with an IC50 value of 630 nM. The RORγ antagonism of 39 was 7-fold higher than that of hit compound C11. These results represent a promising starting point for developing potent small molecule RORγ inverse agonists for the treatment of autoimmune diseases, such as rheumatoid arthritis, psoriasis, and multiple sclerosis.

•FABP4 is a promising drug target for treating inflammation-related diseases.•Seven hits were obtained by using structure-based virtual screening.•Similarity searches led to compounds with promising activity.•An effective blockade of inflammatory response was validated in cell based assays.•MD and mutagenesis studies validated important residues for ligand binding.Adipocyte fatty acid binding protein (AFABP, FABP4) has been proven to be a potential therapeutic target for diabetes, atherosclerosis and inflammation-related diseases. In this study, a series of new scaffolds of small molecule inhibitors of FABP4 were identified by virtual screening and were validated by a bioassay. Fifty selected compounds were tested, which led to the discovery of seven hits. Structural similarity-based searches were then performed based on the hits and led to the identification of one high affinity compound 33b (Ki = 0.29 ± 0.07 μM, ΔTm = 8.5 °C). This compound’s effective blockade of inflammatory response was further validated by its ability to suppress pro-inflammatory cytokines induced by lipopolysaccharide (LPS) stimulation. Molecular dynamics simulation (MD) and mutagenesis studies validated key residues for its inhibitory potency and thus provide an important clue for the further development of drugs.

Amantadine derivatives have been the only drugs marketed as M2 inhibitors of influenza A for decades. The identification of pinanamine as a novel M2 inhibitor suggests that M2 ion channels can accommodate more types of hydrophobic scaffolds. Herein, we further investigated the M2 ion channels and identified camphor derivatives as new types of M2 inhibitors. Compound 18 was found to be more potent than amantadine against wild-type influenza virus. The molecular docking revealed that compound 18 occupies more space in the M2 ion channel than amantadine and thus exhibits enhanced activity.

Nuclear receptors (NRs) are ligand-regulated transcription factors that regulate metabolism, development and immunity. The NR superfamily is one of the major classes of drug targets for human diseases. Retinoic acid receptor-related orphan receptor (ROR) α, β and γ belong to the NR superfamily, and these receptors are still considered as 'orphan' receptors because the identification of their endogenous ligands has been controversial. Recent studies have demonstrated that these receptors are regulated by synthetic ligands, thus emerge as important drug targets for the treatment of multiple sclerosis, rheumatoid arthritis, psoriasis, etc. Studying the structural basis and ligand development of RORs will pave the way for a better understanding of the roles of these receptors in human diseases. Here, we review the structural basis, disease relevance, strategies for ligand identification, and current status of development of therapeutic ligands for RORs.

•RORγ is a promising drug target for treating Th17-mediated autoimmune diseases.•A hit compound was obtained by structure-based virtual screening.•77 new compounds were designed and prepared starting from the hit compound.•Several compounds acted as RORγ inhibitors and exhibited promising activities.•SARs were analysed based on predicted binding modes and assessed activity.Retinoic acid receptor-related orphan receptor γ (RORγ), a member of the nuclear hormone receptor superfamily, is a promising therapeutic target for treating Th17-mediated autoimmune diseases. We performed structure-based virtual screening targeting the RORγ ligand-binding domain. Among the tested compounds, s4 demonstrated RORγ antagonistic activities with micromolar IC50 values in both an AlphaScreen assay (20.27 μM) and a cell-based reporter gene assay (11.84 μM). Optimization of the s4 compound led to the identification of compounds 7j, 8c, 8k, and 8p, all of which displayed significantly enhanced RORγ inhibition with IC50 values of 40–140 nM. These results represent a promising starting point for developing potent small molecule RORγ inhibitors.Benzo[cd]indol-2(1H)-one derivatives were developed as new RORγ inhibitors for developing therapeutic drug treating Th17 mediated autoimmune diseases.

Abscisic acid (ABA) is the most important hormone for plants to resist drought and other abiotic stresses. ABA binds directly to the PYR/PYL family of ABA receptors, resulting in inhibition of type 2C phosphatases (PP2C) and activation of downstream ABA signaling. It is envisioned that intervention of ABA signaling by small molecules could help plants to overcome abiotic stresses such as drought, cold and soil salinity. However, chemical instability and rapid catabolism by plant enzymes limit the practical application of ABA itself. Here we report the identification of a small molecule ABA mimic (AM1) that acts as a potent activator of multiple members of the family of ABA receptors. In Arabidopsis, AM1 activates a gene network that is highly similar to that induced by ABA. Treatments with AM1 inhibit seed germination, prevent leaf water loss, and promote drought resistance. We solved the crystal structure of AM1 in complex with the PYL2 ABA receptor and the HAB1 PP2C, which revealed that AM1 mediates a gate-latch-lock interacting network, a structural feature that is conserved in the ABA-bound receptor/PP2C complex. Together, these results demonstrate that a single small molecule ABA mimic can activate multiple ABA receptors and protect plants from water loss and drought stress. Moreover, the AM1 complex crystal structure provides a structural basis for designing the next generation of ABA-mimicking small molecules.