ABSTRACT Following the rise in resistance to PD‐1/PD‐L1 immune checkpoint blockade therapy in patients with cancer, the TIGIT/CD155 axis has emerged as a major focus of current research. Several competitive binding inhibitors, including antibodies and small molecules targeting TIGIT or CD155, have demonstrated efficacy in suppressing tumor growth and metastasis, either in preclinical models or clinical trials. This review summarizes the expression patterns of CD155, TIGIT, and DNAM‐1 across immune cell subsets, along with the downstream signaling pathways modulated by these interactions. Furthermore, it provides an analysis of predicted binding sites among relevant domains. The article also systematically catalogs current therapeutic strategies targeting the CD155/TIGIT axis in patients, including novel emerging modalities.
Lactoperoxidase (LPO) is a heme-containing enzyme widely distributed in mammalian secretions, contributing to host defense through the generation of antimicrobial oxidants. Unintended inhibition of LPO by therapeutic agents may impair mucosal immunity, making the investigation of potential inhibitors clinically relevant. In this study, the inhibitory effects of 11 acetohydrazide-based sulfonamide derivatives on bovine milk LPO were investigated using combined biochemical and computational approaches. The compounds exhibited diverse inhibition profiles, with IC50 values ranging from 2.32 ± 0.14 to 13.4 ± 2.05 μM. The corresponding Kᵢ values were determined in the low micromolar range, varying from 1.25 ± 0.05 to 7.53 ± 0.03 μM. Among them, 4b-2 (3-pyridyl) and 4a-5 (2-naphthyl) derivatives were identified as the most potent inhibitors, acting through a competitive inhibition mechanism with low micromolar Kᵢ values. The binding mechanisms of relatively active compounds in the enzymatic assay were explored through molecular modeling. The docking study disclosed that compounds 4a-5 and 4b-2 would show higher binding potential to the LPO structure. The two compounds formed stable complexes with the enzyme structure according to the molecular dynamics (MD) simulation study. These interactions were mainly governed by hydrogen bonding and π-π stacking interactions involving key residues in the heme-containing active site, supporting a competitive binding mode consistent with the kinetic data. Overall, the combined biochemical and computational findings suggest that acetohydrazide-based sulfonamides represent promising scaffolds for the development of potent and selective LPO inhibitors and provide new insights into the molecular recognition patterns governing their interaction with the LPO active site.
We present a high-speed force microscopy platform mounted on a confocal microscope with a z sample stage enabling long-range, high-speed force spectroscopy measurements on biological samples. The control software is built on a field-programmable gate array (FPGA)-based data acquisition and processing system, complemented with a custom graphical user insterface (GUI). We introduce smart algorithms based on probe-engagement prediction algorithms that leverage previously measured probe-sample contact to accelerate the probe engagement to mm/s and decelerate it in proximity of contact to user-defined μm/s velocities. This significantly reduces long-range force curve acquisition time and data density. Using this system, we provide proof-of-concept mechanical maps of cell clusters to extract topography and viscoelastic parameters. To further explore the versatility of our system, we probed the forces required to extract membrane tethers from monocytic cells using ultrashort cantilevers functionalised with adhesion molecules. Our system allowed us to cover retract velocities from ~1 μm/s up to ~6000 μm/s, and to explore the dynamics of tether formation at physiologically relevant velocities. Our results show that coupling extended z displacement with the prediction-based engagement algorithms enables rapid, quantitative mechanical mapping of heterogeneous biological samples with large topography variation and supports measurements requiring long distances at high velocities.
Immunoglobulin M (IgM) is the first class of antibody produced in response to pathogens. It also plays an important role in regulating the immune response, including in autoimmunity. IgM pentamers consist of an Fc core composed of Cμ2, Cμ3, and Cμ4 domains, as well as 10 Fab domains composed of Cμ1 and a variable domain. In this study, we use high-resolution atomic force microscopy (AFM) topography to constrain the reconstruction of pentameric IgM Fc core pseudo-atomic model (without Fabs). Reconstruction is performed in two stages using the AFM-Assembly pipeline. First, we fit the known cryo-EM structure of the inner core of the IgM Fc (Cμ3-Cμ4) and the known x-ray structure of Cμ2 beneath the AFM topographs using the DockAFM tool. Second, the two structural units are assembled to generate a complete pentameric IgM Fc core structure. The experimentally constrained reconstruction of the IgM Fc core reveals a divergence in the assembly of the five Cμ2 monomers: the first and last monomers (M1 and M5) are tightly attached to the inner core, while the remaining monomers (M2-M4) are more loosely bound. This reconstruction describes multiple alternative conformations for the attachment of the Cμ2 domains, suggesting that the reconstruction protocol integrates molecular flexibility present in molecules individually deposited on the AFM substrate.
