Heat shock protein 10 of Chlamydophila pneumoniae induces proinflammatory cytokines through Toll-like receptor (TLR) 2 and TLR4 in human monocytes THP-1

Abstract

Inflammatory response is the first line of infection. Previous studies have suggested that Chlamydophila pneumoniae heat shock protein (CHSP) 60 is present in human atheromata, and it plays an important role on the chronic infection elicited by C. pneumoniae. Here, we demonstrated in vitro the impact of heat shock protein 10 (HSP10) of C. pneumoniae on THP-1 cells and the role of Toll-like receptors (TLRs) in the procedures of inflammatory response. The production of proinflammatory cytokines, including tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-6, and IL-1beta were induced by recombinant HSP10 dose-dependently, and the proinflammatory activity of HSP10 was greatly reduced by heating and deproteinization treatment. The expression of TLR4 and TLR2 on the cultured cells were determined by reverse transcriptase-polymerase chain reaction and immunofluorescence. Peritoneal macrophages isolated from wild-type (C3H/HeN) and TLR4-deficient mice (C3H/HeJ) were respectively stimulated with endotoxin-free proteins. Cytokine responses after stimulation were significantly different, depending on the presence of TLR4. The effect on cytokine expression was blocked by anti-TLR2 or anti-TLR4 MAb partially or dramatically. Thus, HSP10 of C. pneumoniae which could elicit inflammatory reactions in human monocytes may contribute to the inflammatory processes in Chlamydophila infection, and the effects were mediated by TLR4 and, to a lesser extent, TLR2.

Tet2 restrains inflammatory gene expression in macrophages

“…Previously published primer sequences were used for amplification of mouse Tet1, Tet2, Tet3, tumor necrosis factor (TNF) α, IL-6, IL-1β, and Arg1 and human TET1, TET2, TET3, IL-1β, and IL-6 [14,[28][29][30][31][32]. Human β-actin and mouse β-2-microglobulin (B2M) were used as internal controls [33,34]. Next, 20 ng of cDNA was amplified using the DyNAmo Flash SYBR Green quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) Kit (Thermo Fisher Scientific) in a Viia 7 Real-Time PCR Machine (Applied Biosystems, Foster City, CA) courtesy of the Berman Laboratory (Queen's University).…”

Curcumin affects ox‑LDL‑induced IL‑6, TNF‑α, MCP‑1 secretion and cholesterol efflux in THP‑1 cells by suppressing the TLR4/NF‑κB/miR33a signaling pathway

“…Toll-like receptors (TLRs) are pattern recognition receptors present on macrophage surfaces, which are extensively expressed on macrophages in lipid-rich atherosclerotic plaques in humans and mice and play an essential role in the host defense response (12). It has been shown by Zhou et al (13) that TLR2 and TLR4 are highly expressed in human umbilical vein endothelial cells and in the human acute monocytic leukemia cell line, THP-1 epidermal cells. The expression of TLR2 and TLR4 is induced by oxidized (ox)-low-density lipoprotein (LDL), and in TLR2 or TLR4 deficient cells, the formation of foam cells decreases significantly (14).…”

Hypothetical protein Cpn0423 triggers NOD2 activation and contributes to Chlamydia pneumoniae-mediated inflammation

“…NOD2, TLR3, and TLR9 [ 13 , 15 ]. Recent studies strongly support an important role of C. pneumoniae HSPs, LPS and MOMP played in driving innate immune responses [ 16 , 36 ], while TLR2 and TLR4 are both important to orchestrate cytokine and chemokine responses and host defense against C. pneumoniae infection in vivo. TLR3 and TLR9 are located primarily on the membranes of intracellular compartments and mainly responsible for the recognition of microbial nucleic acids [ 13 ].…”

“…To the best of our knowledge, it is difficult to evaluate how much C. pneumonia protein can be secreted from infected host cells or what C. pneumonia protein amount are presented in infected cells. Thus, the concentration of Cpn0423 used in this paper was based on our pilot studies and previous reported [ 16 , 34 ]. Here we showed for the first time the discovery of recombinant protein Cpn0423 as an activator and its effects on pneumonia.…”

“…TLRs are embedded in the plasma membrane and recognize conserved pathogen-associated molecules. Studies from our laboratory indicated that heat shock protein 10 (HSP10) of C. pneumoniae could elicit inflammatory reactions mediated by TLR4 [ 16 ]. Others also confirmed that both TLR2 and TLR4 signaling induce early cytokine and chemokine production during C. pneumoniae respiratory infection [ 17 ].…”