Structural Evaluations of a Selective Human STINGA230 Agonist and Its Use in Macrophage Immunotherapies.

Previously we identified a non-nucleotide agonist BDW568 that selectively activates the human STINGA230 allele. Here, we further characterized the mechanism of BDW568 and highlighted its potential use for selectively controlling the activation of engineered macrophages that constitutively express STINGA230 as a genetic adjuvant. We obtained the crystal structure of the C-terminal domain of STINGA230 complexed with BDW-OH (active metabolite) at 1.95 Å resolution. Structure-activity relationship studies revealed that all three heterocycles in BDW568 and the S-acetate side chain are critical for retaining activity. We demonstrated that BDW568 could robustly activate type I interferon signaling in purified human primary macrophages that were transduced with lentivirus expressing STINGA230. In contrast, BDW568 could not stimulate innate immune responses in human primary peripheral blood mononuclear cells in healthy donors in the absence of a STINGA230 allele. This high STING variant specificity suggested a promising application of STINGA230 agonists in macrophage-based therapeutic approaches.

Structural and Biological Evaluations of a Non-Nucleoside STING Agonist Specific for Human STINGA230 Variants.

Previously we identified a non-nucleotide tricyclic agonist BDW568 that activates human STING (stimulator of interferon genes) gene variant containing A230 in a human monocyte cell line (THP-1). STINGA230 alleles, including HAQ and AQ, are less common STING variants in human population. To further characterize the mechanism of BDW568, we obtained the crystal structure of the C-terminal domain of STINGA230 complexed with BDW-OH (active metabolite of BDW568) at 1.95 Å resolution and found the planar tricyclic structure in BDW-OH dimerizes in the STING binding pocket and mimics the two nucleobases of the endogenous STING ligand 2',3'-cGAMP. This binding mode also resembles a known synthetic ligand of human STING, MSA-2, but not another tricyclic mouse STING agonist DMXAA. Structure-activity-relationship (SAR) studies revealed that all three heterocycles in BDW568 and the S-acetate side chain are critical for retaining the compound's activity. BDW568 could robustly activate the STING pathway in human primary peripheral blood mononuclear cells (PBMCs) with STINGA230 genotype from healthy individuals. We also observed BDW568 could robustly activate type I interferon signaling in purified human primary macrophages that were transduced with lentivirus expressing STINGA230, suggesting its potential use to selectively activate genetically engineered macrophages in macrophage-based approaches, such as chimeric antigen receptor (CAR)-macrophage immunotherapies.

Evaluation of Physico-Mechanical Properties on Oil Extracted Ground Coffee Waste Reinforced Polyethylene Composite.

The current work discusses ground coffee waste (GCW) reinforced high-density polyethylene (HDPE) composite. GCW underwent two types of treatment (oil extraction, and oil extraction followed by mercerization). The composites were prepared using stacking HDPE film and GCW, followed by hot compression molding with different GCW particle loadings (5%, 10%, 15% and 20%). Particle loadings of 5% and 10% of the treated GCW composites exhibited the optimum level for this particular type of composite, whereby their mechanical and thermal properties were improved compared to untreated GCW composite (UGC). SEM fracture analysis showed better adhesion between HDPE and treated GCW. The FTIR conducted proved the removal of unwanted impurities and reduction in water absorption after the treatment. Specific tensile modulus improved for OGC at 5 vol% particle loading. The highest impact energy absorbed was obtained by OGC with a 16% increment. This lightweight and environmentally friendly composite has potential in high-end packaging, internal automotive parts, lightweight furniture, and other composite engineering applications.