Disease

When a mammal is exposed to high temperatures over a long period of time a significant amount of cell death can occur. This process termed hyperthermia can have significant affects on brain function as a result of neuronal cell death. During hyperthermia it has been shown that mice upregulate a specific heat shock protein (HSP70) in several neuronal cell types. Increased levels of HSP 70 may facilitate survival during periods of heat stress. Normally, HSP70 mRNA is never found in neuronal tissues but after hyperthermia induction HSF1 trimerizes and begins to actively enhance the expression of HSP70. For some time it was thought that HSP70 expression could be predict which neuronal cells will survive heat stress. Unfortunately, it was shown that HSP 70 is upregulated broadly following heat shock and that any given neuronal cell has an equal probability of survival. Other proteins likely contribute to protection of neuronal tissue against heat shock but their identity has yet to be determined. It is still unclear how HSF responds to stress in the brain or whether HSP70 is truly protecting neuronal tissues from heat damage. Even so the striking upregulation of HSP70 during hyperthermia strongly suggests that HSF plays a pivotal role in protecting neurons from heat damage.