Heat shock proteins (HSPs) are small polypeptide groups that are classified into families based on molecular weight. They are expressed by cells in the body as a protection against harmful environmental conditions. HSPs are expressed in situations where cell survival may be compromised. The stimulus for HSP ex
Heat shock proteins are involved in many chaperone functions. Their ex
HSPs also function as a potential cytoprotective protein. Under stressful conditions such as cytotoxic injury, heat shock, oxidative stress, radiation, viral infection, and chemical exposure, HSPs have long been known to serve as protein chaperones in the sense that they assist in protein folding and the correct attainment of functional three-dimensional configuration, while preventing incorrect folding and protein aggregation.
While recent studies that highlight the critical functions of Heat Shock Proteins in various cellular processes have made them an increasing popular subject of interest to medical specialists in a wide variety of fields, including infectious disease, immunology, oncology, and autoimmunity, heat shock proteins are relatively unstudied in the field of endodontics. There are only two articles available in the endodontic literature that deal with HSPs and they both study HSP27. HSP27 is expressed in many cell types and tissues at specific stages of development and differentiation. Overexpressed HSP27 protects against apoptotic cell death triggered by various stimuli, including hyperthermia and oxidative stress. The first article studied the role of HSP27 in the pathogenesis of periapical lesions by using immunohistochemistry techniques. An overex
Heat Shock Proteins may activate the immune response but also dampen the inflammatory pathways by presenting antigens to the immune system. HSPs have been linked to the therapy of both cancer and inflammatory diseases, approaches that utilize contrasting immune properties of these proteins. It would appear that HSP family members HSP60 and HSP70, whether from external sources or induced locally during inflammation, can be processed by antigen-presenting cells and that HSP-derived epitopes then activate regulatory T cells to suppress inflammatory disease. The HSP70 family constitutes the most conserved and best studied class of HSPs. Human cells contain several HSP70 family members. Under normal conditions, HSP70 proteins function as ATP-dependent molecular chaperones by assisting the folding of newly synthesized polypeptides, the assembly of multiprotein complexes, and the transport of proteins across cellular membranes. HSP70 also reduces or blocks caspase activation and suppresses mitochondrial damage and nuclear fragmentation.
Prominent members of the HSP90 family of proteins are HSP90α and HSP90β. These two HSP90 isoforms are essential for the viability of eukaryotic cells. They are rather abundant constitutively, make up 1- 2% of cytosolic proteins, and can be further stimulated in their ex
HSP110 is one of major heat shock proteins of eukaryotic cells and is a diverged relative of the HSP70 family. Based on strong inducibility, quantity, and presence in many cell types, HSP110 has also been recognized for the last two decades as a major heat shock protein, specifically in mammalian cells. HSP110 exists in parallel with the HSP70s in the cytoplasm and nucleus in diverse organisms, argues strongly for related but differential functions and properties for these two major stress protein groups. The overex
Extracellular HSPs can also stimulate the release of tumor necrosis factor alpha (TNF-α), interleukins - 1β, -6 and -12, nitric oxide, as well as chemokines by monocytes/macrophages, which may serve as endogenous danger signals to alert the host defense system through their cytokine-like function contributing to lesion development/expansion.