Phagocytosis and heat shock response in human monocytes-macrophages

The heat shock response represents a general physiological cellular reprogramming of gene expression secondary to exposure to multiple different stresses such as heat or oxygen free radicals. It is assumed that this response is turned on in order to protect cells, or to permit better recovery, from the detrimental effects of such stresses. During erythrophagocytosis, heat shock proteins and heme oxygenase synthesis are induced in human monocytes-macrophages. Whereas induction of heme oxygenase appears to be related to the hemoglobin-released iron, the factor(s) responsible for heat shock protein induction remain elusive. The respective roles of phagocytosis itself, oxygen free radicals, calcium, cytoskeletal alterations and oncogene expression are discussed.