Endosomal membrane cholesterol

Endosomal membrane cholesterol in antigen-presenting cells (APCs) refers to the specific pool of sterols located within the membranes of the endocytic pathway, particularly late endosomes and lysosomes. This cholesterol pool is a critical determinant of membrane biophysical properties, influencing the spatial organization of proteins required for antigen processing and cross-presentation to T cells (Nature Communications, 2021). In the context of the tumor microenvironment, APCs often accumulate excessive endosomal cholesterol, which leads to membrane rigidity and the sequestration of essential signaling molecules, ultimately impairing anti-tumor immunity (Cell Reports, 2018). Pharmacological modulation of this target using agents like hydroxypropyl-beta-cyclodextrin or ACAT1 inhibitors can mobilize sequestered cholesterol, thereby restoring the recruitment of the antigen-presentation machinery and boosting the efficacy of immunotherapies. Beyond oncology, endosomal cholesterol is a focal point in lysosomal storage disorders such as Niemann-Pick disease type C, where defective transport leads to massive accumulation and cellular dysfunction (UniProt P11894). Furthermore, many viruses, including Ebola and SARS-CoV-2, exploit endosomal cholesterol for membrane fusion and cellular entry, making it a broad-spectrum target for infectious diseases (PubMed, 2020).

Other names

Late endosomal cholesterolLysosomal cholesterol poolIntracellular cholesterolEndocytic membrane sterols

Modulation of endosomal membrane cholesterol levels alters membrane fluidity and the organization of lipid rafts, which in turn regulates the recruitment and stability of the antigen-presentation machinery, such as the TAP complex and Sec61 translocon, thereby enhancing or inhibiting MHC-I and MHC-II mediated immune responses (Nature Communications, 2021).