• Interactions between extracellular Hsp72 and blood cells

      Williams, John H. H.; Ireland, H. Elyse; Williams, Helen (University of Liverpool (University of Chester), 2010-12)
      In recent years, compelling evidence has accumulated suggesting heat shock proteins (HSPs) which are generally believed to be localised and functioning mainly within eukaryotic cells as cyto-protective molecular chaperones, are also localised in the extracellular milieu. Depending on their localisation, on the cell surface (membrance-bound or embedded), or in the peripheral circulation, extracellular HSPs may induce apoptotic cell death, or in contrast protect cells from cell damage and/or cell death when exposed to cellular stress, or may even elicit a stimulatory effect on the innate immune response including cell activiation and cytokine secretion. Hence, the localisation of intracellular and extracellular HSPs appears to be critical in determining their roles in terms of stimulating cell death, cyto-protection, or immune activiation under normal physiological conditions and following exposure to stress stimuli. This thesis describes the intracellular expression, up-regulation, and cell surface localisation of endogenous HSPs: HSP27, Hsp60, Hsp72 and Hsp90 by flow cytometry, florescence microscopy and Western blotting, under control conditions and in response to environmental stress using in vitro and ex vivo models with the intention of determining their physiological roles. The ability of extracellularly administered HSPs (Hsp70 and Hsp72) to protect cultured U937 cells in vitro or peripheral primary human leukogytes or erythrocytes ex vivo from various stress stimuli was demonstrated and was found to be dependent on surface binding and/or internalisation via scavenger receptors (SRs) or phosphatidylserine (PS), which could be blocked by receptor specific ligands. Extracellular HSPs were also shown to be able to stimulate an immune response through the induction of U937 monocyte differentiation into macrophages as evidenced through the up-regulation of the surface receptors: CD36, SR-A1 and CD91 analysed by flow cytometry. These proteins were able to stimulate TNF-x and IL-10 production and secretion by U937 macrophages, shown by ELISA, and chemotatic properties were demonstrated using Boyden chambers. The cyto-protective and immune regulatory effects of extracellular HSPs have potential therapeutic value as treatments in a wide variety of clinical situations.
    • Monocytes/macrophages express CCR9 in rheumatoid arthritis and CCL25 stimulates their differentiation

      Schmutz, Caroline; Cartwright, Alison; Williams, Helen; Haworth, Oliver; Williams, John H. H.; Filer, Andrew; Salmon, Mike; Buckley, Christopher D.; Middleton, Jim F.; Keele University/University of Birmingham ; Keele University ; University of Chester ; University of Birmingham ; University of Chester ; University of Birmingham ; University of Birmingham ; University of Birmingham ; Keele University/University of Bristol (BioMed Central, 2010-08-05)
      Abstract Introduction Monocytes/macrophages accumulate in the rheumatoid (RA) synovium where they play a central role in inflammation and joint destruction. Identification of molecules involved in their accumulation and differentiation is important to inform therapeutic strategies. This study investigated the expression and function of chemokine receptor CCR9 in the peripheral blood (PB) and synovium of RA, non-RA patients and healthy volunteers. Methods CCR9 expression on PB monocytes/macrophages was analysed by flow cytometry and in synovium by immunofluorescence. Chemokine receptor CCR9 mRNA expression was examined in RA and non-RA synovium, monocytes/macrophages from PB and synovial fluid (SF) of RA patients and PB of healthy donors using the reverse transcription polymerase chain reaction (RT-PCR). Monocyte differentiation and chemotaxis to chemokine ligand 25 (CCL25)/TECK were used to study CCR9 function. Results CCR9 was expressed by PB monocytes/macrophages in RA and healthy donors, and increased in RA. In RA and non-RA synovia, CCR9 co-localised with cluster of differentiation 14+ (CD14+) and cluster of differentiation 68+ (CD68+) macrophages, and was more abundant in RA synovium. CCR9 mRNA was detected in the synovia of all RA patients and in some non-RA controls, and monocytes/macrophages from PB and SF of RA and healthy controls. CCL25 was detected in RA and non-RA synovia where it co-localised with CD14+ and CD68+ cells. Tumour necrosis factor alpha (TNFα) increased CCR9 expression on human acute monocytic leukemia cell line THP-1 monocytic cells. CCL25 induced a stronger monocyte differentiation in RA compared to healthy donors. CCL25 induced significant chemotaxis of PB monocytes but not consistently among individuals. Conclusions CCR9 expression by monocytes is increased in RA. CCL25 may be involved in the differentiation of monocytes to macrophages particularly in RA.