• Hsp72 translocation and secretion in in vivo and in vitro models

      Williams, John H. H.; Andrew, Sarah M.; Leoni, Francesca (University of Liverpool (Chester College of Higher Education), 2009-03)
      Evidence suggesting that Hsp72 is actively participating in cellular signalling as well interacting with immune system dynamics has been increasing. This is true in healthy, stressed and diseased cells but to different degrees. Modulation of the plasma membrane association and secretion in the extracellular environment by different types of stressors is the key event that leads to different degrees of immune system activation. Hence a better understanding of the mechanisms of Hsp72 secretion and association with plasma membrane is crucial. This thesis investigated the tissue source and mechanism of Hsp72 surface presentation to plasma membrane structures and release in relation with different cellular and physiological stressors. In vivo models confirmed that different tissue types determine specific Hsp72 responses following the same stress and increase serum Hsp72 dependant on intensity and duration of the stress. Diseases models confirm that Hsp72 responses in specific cell populations is related to disease progression, while in vitro models clearly showed that there are multiple mechanisms of secretion and surface presentation, dependent on the nature of the stressor as well as the intensity and duration. This observations clearly change the view of extracellular Hsp72 as a danger signal and lead to a revision of the original danger model. It also suggests that manipulation of Hsp72 translocation through the different pathways involved may prove effective therapeutically.