Blumberger, J. | bioRxiv Science

bioRxiv2024

Nanomaterials trigger functional responses in primary human immune cells

Targeting the immune system with nanoparticles (NPs) to deliver immunomodulatory molecules emerged as a solution to address intra-tumoral immunosuppression and enhance therapeutic response. While the potential of nanoimmunotherapies in reactivating immune cells has been evaluated in several preclinical studies, the impact of drug-free nanomaterials on the immune system remains unknown. Here, we characterize the molecular and functional response of human NK cells and pan T cells to a selection of five NPs that are commonly used in biomedical applications. After a pre-screen to evaluate the toxicity of these nanomaterials on immune cells, we selected ultrasmall silica-based gadolinium (Si-Gd) NPs and poly(lactic-co-glycolic acid) (PLGA) NPs for further investigation. Bulk RNA-sequencing and flow cytometry analysis showcase that PLGA NPs trigger a transcriptional priming towards activation in NK and pan T cells. While PLGA NPs improved NK cells anti-tumoral functions in cytokines-deprived environment, Si-Gd NPs significantly impaired T cells activation as well as functional responses to a polyclonal antigenic stimulation. Altogether, we identified PLGAs NPs as suitable and promising candidates for further targeting approaches aiming to reactivate the immune system of cancer patients.

immunology↗

bioRxiv2021

Electron transfer parameters for Methemoglobin formation in mutant Hemoglobin α-chains.

Hemoglobin mediated transport of dioxygen (O2) critically depends on the stability of the reduced (Fe2+) form of the Heme cofactors. Some protein mutations stabilize oxidized (Fe3+) state (Methemoglobin, Hb M) causing methemoglobinemia and can be lethal above 30 %. Majority of the analyses of factors influencing Hb oxidation are retrospective and give insights only for inner sphere mutations of Heme (His58, His87). Herein, we report the first all atom MD simulations on redox states and calculations of the Marcus ET parameters for the -chain Hb oxidation and reduction rates for Hb M. The Hb (wild type), and most of the studied -chain variants maintain globin structure except the Hb M Iwate (H87Y). Using linear response approximation we calculated average energy gaps (<{Delta}E>), total ({lambda}), protein ({lambda}prot), solvent ({lambda}solv) reorganization energies, and redox potentials (E{degrees}), and oxidation free energies ({Delta}G{degrees}). The total {lambda} ranges from 0.685 - 0.730 eV in agreement with literature on Hb and similar Heme proteins. The mutants forming Hb M tend to lower the E{degrees} and thus stabilize the oxidized (Fe3+) state (e.g. the Hb Miyagi variant with K61E mutation). Solvent reorganization ({lambda}solv 73 - 96 %) makes major contributions to {lambda}, while protein reorganization ({lambda}prot) accounts for 27 - 30 % except for the Miyagi and J-Buda variants ({lambda}prot [~] 4 %). Analysis of Heme-solvent H-bonding interactions among variants provide insights into the role of Lys61 residue in stabilizing Fe2+ state and ET parameters. The ET parameters provide valuable insights into the Hb oxidation to Hb M in agreement with the experimental data. Thus our methodology explains the effect of mutations on the structure, stability and Hb oxidation, and has potential for the prediction of methemoglobinemia.

biochemistry↗