Obesity increases the risk for a number of diseases including cardiovascular diseases and type 2 diabetes. Excess saturated fatty acids (SFAs) in obesity play a significant role in cardiovascular diseases by activating innate immunity responses. However, the mechanisms by which SFAs activate the innate immune system are not fully known. Here we report that palmitic acid (PA), the most abundant circulating SFA, induces myocardial inflammatory injury through the Toll-like receptor 4 (TLR4) accessory protein MD2 in mouse and cell culture experimental models. Md2 knockout mice are protected against PA- and high-fat diet-induced myocardial injury. Studies of cell surface binding, cell-free protein–protein interactions and molecular docking simulations indicate that PA directly binds to MD2, supporting a mechanism by which PA activates TLR4 and downstream inflammatory responses. We conclude that PA is a crucial contributor to obesity-associated myocardial injury, which is likely regulated via its direct binding to MD2.

The epidermal growth factor receptor (EGFR) has been a particular interest for drug development for treatment of non-small-cell lung cancer (NSCLC). The current third-generation EGFR small-molecule inhibitors, especially osimertinib, are at the forefront clinically for treatment of patients with NSCLC. However, a high percentage of these treated patients developed a tertiary cystein-797 to serine-790 (C797S) mutation in the EGFR kinase domain. This C797S mutation is thought to induce resistance to all current irreversible EGFR TKIs. In this Miniperspective, we present key mechanisms of resistance in response to third-generation EGFR TKIs, and emerging reports on novel EGFR TKIs to combat the resistance. Specifically, we analyze the allosteric and ATP-competitive inhibitors in terms of drug discovery, binding mechanism, and their potency and selectivity against EGFR harboring C797S mutations. Lastly, we provide some perspectives on new challenges and future directions in this field.

Sepsis claims an estimated 30 million episodes and 6 million deaths per year, and treatment options are rather limited. Human neutrophil peptides 1–3 (HNP1–3) are the most abundant neutrophil granule proteins but their neutrophil content varies because of unusually extensive gene copy number polymorphism. A genetic association study found that increased copy number of the HNP-encoding gene DEFA1/DEFA3 is a risk factor for organ dysfunction during sepsis development. However, direct experimental evidence demonstrating that these risk alleles are pathogenic for sepsis is lacking because the genes are present only in some primates and humans. Here, we generate DEFA1/DEFA3 transgenic mice with neutrophil-specific expression of the peptides. We show that mice with high copy number of DEFA1/DEFA3 genes have more severe sepsis-related vital organ damage and mortality than mice with low copy number of DEFA1/DEFA3 or wild-type mice, resulting from more severe endothelial barrier dysfunction and endothelial cell pyroptosis after sepsis challenge. Mechanistically, HNP-1 induces endothelial cell pyroptosis via P2X7 receptor-mediating canonical caspase-1 activation in a NLRP3 inflammasome-dependent manner. Based on these findings, we engineered a monoclonal antibody against HNP-1 to block the interaction with P2X7 and found that the blocking antibody protected mice carrying high copy number of DEFA1/DEFA3 from lethal sepsis. We thus demonstrate that DEFA1/DEFA3 copy number variation strongly modulates sepsis development in vivo and explore a paradigm for the precision treatment of sepsis tailored by individual genetic information.

The androgen receptor (AR) plays important roles in gene expression regulation, sexual phenotype maintenance, and prostate cancer (PCa) development. The communications between the AR ligand-binding domain (LBD) and its coactivator are critical to the activation of AR. It is still unclear how the ligand binding would affect the AR-coactivator interactions. In this work, the effects of the ligand binding on the AR-coactivator communications were explored by molecular dynamics (MD) simulations. The results showed that the ligand binding regulates the residue interactions in the function site AF-2. The ligand-to-coactivator allosteric pathway, which involves the coactivator, helix 3 (H3), helix 4 (H4), the loop between H3 and H4 (L3), and helix 12 (H12), and ligands, was characterized. In addition, the interactions of residues on the function site BF-3, especially on the boundary of AF-2 and BF-3, are also affected by the ligands. The MM/GBSA free energy calculations demonstrated that the binding affinity between the coactivator and apo-AR is roughly weaker than those between the coactivator and antagonistic ARs but stronger than those between the coactivator and agonistic ARs. The results indicated that the long-range electrostatic interactions and the conformational entropies are the main factors affecting the binding free energies. In addition, the F876L mutation on AR-LBD affects the ligand-to-coactivator allosteric pathway, which could be the reason for point mutation induced tolerance for the antagonistic drugs such as enzalutamide. Our study would help to develop novel drug candidates against PCa.

Androgen receptor (AR) is a ligand-activated transcription factor that plays a pivotal role in the development and progression of many severe diseases such as prostate cancer, muscle atrophy, and osteoporosis. Binding of ligands to AR triggers the conformational changes in AR that may affect the recruitment of coactivators and downstream response of AR signaling pathway. Therefore, AR ligands have great potential to treat these diseases. In this study, we searched for novel AR ligands by performing a docking-based virtual screening (VS) on the basis of the crystal structure of the AR ligand binding domain (LBD) in complex with its agonist. A total of 58 structurally diverse compounds were selected and subjected to LBD affinity assay, with five of them (HBP1-3, HBP1-17, HBP1-38, HBP1-51, and HBP1-58) exhibiting strong binding to AR-LBD. The IC50 values of HBP1-51 and HBP1-58 are 3.96 µM and 4.92 µM, respectively, which are even lower than that of enzalutamide (Enz, IC50 = 13.87 µM), a marketed second-generation AR antagonist. Further bioactivity assays suggest that HBP1-51 is an AR agonist, whereas HBP1-58 is an AR antagonist. In addition, molecular dynamics (MD) simulations and principal components analysis (PCA) were carried out to reveal the binding principle of the newly-identified AR ligands toward AR. Our modeling results indicate that the conformational changes of helix 12 induced by the bindings of antagonist and agonist are visibly different. In summary, the current study provides a highly efficient way to discover novel AR ligands, which could serve as the starting point for development of new therapeutics for AR-related diseases.