Myocardial Ischemia Activates an Injurious Innate Immune Signaling via Cardiac Heat Shock Protein 60 and Toll-like Receptor 4

Introduction. Lipopolysaccharide endotoxin (LPS) is responsible for septic shock and multiorgan failure, but pretreatment of rats with low doses of LPS reduced pancreatic acute damage.Aim. We investigated the effects of the endotoxemia induced in the early period of life on Toll-like receptor 4 (TLR4), heat shock protein 60 (HSP60) and proapoptotic Bax, caspase-9 and -3 or antiapoptotic Bcl-2 protein expression in the pancreatic acinar cells of adult animals.Material and Methods. Newborn rats (25 g) were injected with endotoxin (Escherichia coli) for 5 consecutive days. Two months later, pancreatic acinar cells were isolated from all groups of animals and subjected to caerulein stimulation (10−8 M). Protein expression was assessed employing Western blot. For detection of apoptosis we have employed DNA fragmentation ladder assay.Results. Preconditioning of newborn rats with LPS increased TLR4, Caspase-9 and -3 levels, but failed to affect basal expression of HSP60, Bax, and Bcl-2. Subsequent caerulein stimulation increased TLR4, Bcl-2, and caspases, but diminished HSP60 and Bax proteins in pancreatic acinar cells. Endotoxemia dose-dependently increased TLR4, Bax, HSP60, and both caspases protein signals in the pancreatic acini, further inhibiting antiapoptotic Bcl-2.Conclusions. Endotoxemia promoted the induction of HSP60viaTLR4 in the infant rats and participated in the LPS-dependent pancreatic tissue protection against acute damage.

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Heat-shock protein 70 and heat-shock protein 90 associate with Toll-like receptor 4 in response to bacterial lipopolysaccharide

Biochemical Society Transactions ◽

10.1042/bst0320636 ◽

2004 ◽

Vol 32 (4) ◽

pp. 636-639 ◽

Cited By ~ 106

Author(s):

M. Triantafilou ◽

K. Triantafilou

Keyword(s):

Heat Shock ◽

Cell Surface ◽

Heat Shock Protein ◽

Heat Shock Protein 90 ◽

Innate Immune ◽

Toll Like Receptor ◽

Toll Like Receptor 4 ◽

Surface Receptors ◽

Innate Recognition ◽

Shock Proteins

Mammalian responses to bacterial LPS (lipopolysaccharide) from the outer membrane of Gram-negative bacteria can lead to an uncontrolled inflammatory response that can be deadly for the host. It has been shown that the innate immune system employs at least three cell surface receptors, CD14, TLR4 (Toll-like receptor 4) and MD-2, in order to recognize bacterial LPS. In our previous work we have found that Hsps (heat-shock proteins) are also involved in the innate recognition of bacterial products. Their presence on the cell surface, as well as their involvement in the innate recognition process, are poorly understood. In the present study we have investigated the association of TLR4 with Hsp70 and Hsp90 following LPS stimulation, both on the cell surface and intracellularly. Our results show that Hsp70 and Hsp90 form a cluster with TLR4 within lipid microdomains following LPS stimulation. In addition, Hsp70 and Hsp90 seem to be involved in TLR4/LPS trafficking and targeting to the Golgi apparatus, since upon LPS stimulation we found that both Hsps are targeted to the Golgi along with TLR4. The present study sheds new light into the involvement of Hsps in the innate immune response.

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Cutting Edge: Heat Shock Protein 60 Is a Putative Endogenous Ligand of the Toll-Like Receptor-4 Complex

The Journal of Immunology ◽

10.4049/jimmunol.164.2.558 ◽

2000 ◽

Vol 164 (2) ◽

pp. 558-561 ◽

Cited By ~ 1135

Author(s):

Koji Ohashi ◽

Volker Burkart ◽

Stefanie Flohé ◽

Hubert Kolb

Keyword(s):

Heat Shock ◽

Heat Shock Protein ◽

Cutting Edge ◽

Heat Shock Protein 60 ◽

Toll Like Receptor ◽

Endogenous Ligand ◽

Toll Like Receptor 4

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Chlamydial Heat Shock Protein 60 Induces Acute Pulmonary Inflammation in Mice via the Toll-Like Receptor 4- and MyD88-Dependent Pathway

Infection and Immunity ◽

10.1128/iai.00248-09 ◽

2009 ◽

Vol 77 (7) ◽

pp. 2683-2690 ◽

Cited By ~ 27

Author(s):

Yonca Bulut ◽

Kenichi Shimada ◽

Michelle H. Wong ◽

Shuang Chen ◽

Pearl Gray ◽

...

Keyword(s):

Heat Shock ◽

Heat Shock Protein ◽

Lung Inflammation ◽

Chlamydia Pneumoniae ◽

Dependent Manner ◽

Heat Shock Protein 60 ◽

Toll Like Receptor ◽

Acute Lung Inflammation ◽

Toll Like Receptor 4 ◽

Cell Counts

ABSTRACT Heat shock protein 60 derived from Chlamydia pneumoniae (cHSP60) activates Toll-like receptor 4 (TLR4) signaling through the MyD88 pathway in vitro, but it is not known how cHSP60 contributes to C. pneumoniae-induced lung inflammation. We treated wild-type (WT), TLR2−/−, TLR4−/−, or MyD88−/− mice intratracheally (i.t.) with recombinant cHSP60 (50 μg), UV-killed C. pneumoniae (UVCP; 5 × 106 inclusion-forming units/mouse), lipopolysaccharide (2 μg), or phosphate-buffered saline (PBS) and sacrificed mice 24 h later. Bronchoalveolar lavage (BAL) was obtained to measure cell counts and cytokine levels, lungs were analyzed for histopathology, and lung homogenate chemokine concentrations were determined. Bone marrow-derived dendritic cells (BMDDCs) were generated and stimulated with live C. pneumoniae (multiplicity of infection [MOI], 5), UVCP (MOI, 5), or cHSP60 for 24 h, and the expression of costimulatory molecules (CD80 and CD86) was measured by fluorescence-activated cell sorting. cHSP60 induced acute lung inflammation with the same intensity as that of UVCP-induced inflammation in WT mice but not in TLR4−/− or MyD88−/− mice. cHSP60- and UVCP-induced lung inflammation was associated with increased numbers of cells in BAL, increased neutrophil recruitment, and elevated BAL interleukin-6 (IL-6) levels. Both cHSP60 and UVCP induced IL-6 release and CD80 and CD86 expression in WT cells but not in MyD88−/− BMDDCs. cHSP60 stimulated DC activation in a TLR4- and MyD88-dependent manner with an intensity similar to that induced by UVCP. These data suggest that cHSP60 promotes lung inflammation and DC activation via TLR4 and MyD88 and therefore may play a significant role in the pathogenesis of C. pneumoniae-induced chronic inflammatory lung diseases.

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Hexa-Acylated Lipid A Is Required for Host Inflammatory Response to Neisseria gonorrhoeae in Experimental Gonorrhea

Infection and Immunity ◽

10.1128/iai.00890-13 ◽

2013 ◽

Vol 82 (1) ◽

pp. 184-192 ◽

Cited By ~ 17

Author(s):

Xiyou Zhou ◽

Xi Gao ◽

Peter M. Broglie ◽

Chahnaz Kebaier ◽

James E. Anderson ◽

...

Keyword(s):

Neisseria Gonorrhoeae ◽

Lipid A ◽

Innate Immune ◽

Immune Recognition ◽

Toll Like Receptor ◽

Inflammatory Signaling ◽

Toll Like Receptor 4 ◽

Immune Signaling ◽

Content Type ◽

Innate Immune Signaling

ABSTRACTNeisseria gonorrhoeaecauses gonorrhea, a sexually transmitted infection characterized by inflammation of the cervix or urethra. However, a significant subset of patients withN. gonorrhoeaeremain asymptomatic, without evidence of localized inflammation. Inflammatory responses toN. gonorrhoeaeare generated by host innate immune recognition ofN. gonorrhoeaeby several innate immune signaling pathways, including lipooligosaccharide (LOS) and other pathogen-derived molecules through activation of innate immune signaling systems, including toll-like receptor 4 (TLR4) and the interleukin-1β (IL-1β) processing complex known as the inflammasome. The lipooligosaccharide ofN. gonorrhoeaehas a hexa-acylated lipid A.N. gonorrhoeaestrains that carry an inactivatedmsbB(also known aslpxL1) gene produce a penta-acylated lipid A and exhibit reduced biofilm formation, survival in epithelial cells, and induction of epithelial cell inflammatory signaling. We now show thatmsbB-deficientN. gonorrhoeaeinduces less inflammatory signaling in human monocytic cell lines and murine macrophages than the parent organism. The penta-acylated LOS exhibits reduced toll-like receptor 4 signaling but does not affectN. gonorrhoeae-mediated activation of the inflammasome. We demonstrate thatN. gonorrhoeaemsbBis dispensable for initiating and maintaining infection in a murine model of gonorrhea. Interestingly, infection withmsbB-deficientN. gonorrhoeaeis associated with less localized inflammation. Combined, these data suggest that TLR4-mediated recognition ofN. gonorrhoeaeLOS plays an important role in the pathogenesis of symptomatic gonorrhea infection and that alterations in lipid A biosynthesis may play a role in determining symptomatic and asymptomatic infections.

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