Mechanical Response Of Macrophages Induced By M2PEP Peptide

Macrophages are important elements of the immune system,having a role in protecting the organism.On contrary,some macrophages can be related to tumor microenvironment?TME?,resident to tumor tissue or free to float in the vicinity;these are called tumor-associated macrophages?TAMs?.TAMs can promote tumor angiogenesis and migrate to other parts by infiltrating blood vessels.Researchers found a new type of peptide-targeting molecule,M2PEP,specifically able to target TAMs.Most of the recent research focuses on the M2PEP chemical effects on macrophages,while modifications in physical properties,especially mechanical,have not been investigated.Therefore,the main purpose of this thesis work is to explore the mechanical response of macrophages induced by interaction with M2PEP,in correlation with the nature and chemical properties of M2PEP itself while triggering the physiological response and phenotype polarization of macrophages.In the past three decades,the development of Atomic Force Microscope?AFM?has provided a powerful method for measuring the mechanical properties of cells.In this thesis work,AFM will be used as a main research tool to investigate the nanomechanical properties of mouse-derived 264.7RAW macrophages interacting with custom synthetized M2PEP peptides.The modification of morphological and mechanical characteristics of macrophages after co-cultivation with M2PEP,is contextualized using standard biological research methods such as cytotoxicity detection,flow cytometry for phenotype determination and observation by confocal laser scanning microscopy?CLSM?.This study found that M2PEP,as a new type of targeting molecule,has low toxicity for macrophages and show a tendency to induce phenotype polarization.AFM experiments found out that Young's Modulus of macrophages was reduced by 50%at low concentrations(<IC₅₀).At higher concentrations,the Young's Modulus showed an increase,while cell membrane adhesion showed a progressive decline.Combined with CLSM observation,it was found that M2PEP can have an impact on the internal physiology of macrophages and their organelles.This may be an explanation for the influence of M2PEP on the mechanical properties of macrophages.