Targeting immunosenesence promotes clearance of senescent cells.

Abstract

Known as immunosenescence, the major dysregulation of the immune system with age is associated with poor vaccination efficacy, and increased susceptibility to infections, age-related pathologies, and neoplasms, with incidences exacerbated with age. Cellular senescence is a crucial process that puts cells in an irreversible cell-cycle arrest which prevents damaged or stressed cells from uncontrolled propagation and eventually potential malignancy. Paradoxically, senescence also contributes to the occurrence of cancer and increases the risk of metastasis through different secretory mediators. Altogether, the recent use of senotherapy to eliminate senescent cells has been shown to delay tumorigenesis, attenuate age-related deterioration of organs, and promote healthy aging. Interestingly, immune cells have been shown to specifically interact with, and kill senescent cells, thus opening new opportunities for the development of specific therapeutic strategies similar to immunotherapy in cancer. Through its detrimental impact on the immune system, immunosenescence is also leading to the accumulation of senescent cells with age thus further contributing to the occurrence and worsening of multiple age-related pathologies such as cancer. Understanding the molecular and cellular events occurring during the aging process, and triggering immunosenescence as well as the mechanisms by which senescent cells escape immune surveillance would help to improve immune responses to senescent cells and their clearance. In this review, we highlight how senescent cells interact with immune cells, and how immunosenescence-associated phenotypical and functional deregulation hinder the ability of immune cells to clear senescent cells. We further characterize strategies aimed at promoting the clearance of senescent cells by the immune system.