Abstract
Extracellular (ex) HSP60 is increasingly recognized as an agent of cell injury. Previously, we reported that low endotoxin exHSP60 causes cardiac myocyte apoptosis. Our findings supported a role for Toll-like receptor (TLR) 4 in HSP60 mediated apoptosis. To further investigate the involvement of TLR4 in cardiac injury, we studied adult cardiac myocytes from C3H/HeJ (HeJ) mice, which have a mutant, nonfunctional TLR4, and compared the results with parallel studies using wild-type (WT) mice. Nuclear factor κB (NFκB) activation is an early step downstream of TLR4. NFκB was activated 1 h after treatment with HSP60 in WT, but not HeJ mouse myocytes. ExHSP60 caused apoptosis in cardiac myocytes from WT mice, but not in myocytes from the HeJ mutants. To further elucidate the importance of exHSP60 in cardiac myocyte injury, both WT and HeJ mutant isolated mouse adult cardiac myocytes were exposed to hypoxia/reoxygenation. Anti-HSP60 antibody treatment reduced apoptosis in the WT group, but had no effect on the HeJ mutant myocytes. Unexpectedly, necrosis was also decreased in the HeJ mutants. Necrosis after hypoxia/reoxygenation in WT cardiac myocytes was mediated in part by TLR2 and TLR4 through rapid activation of PKCα, followed by increased expression of Nox2, and this was ameliorated by blocking antibodies to TLR2/4. These studies provide further evidence that TLR4 mediates exHSP60-associated apoptosis and that exHSP60 has an important role in cardiac myocyte injury, both apoptotic and necrotic.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 527-535 |
| Number of pages | 9 |
| Journal | Cell Stress and Chaperones |
| Volume | 20 |
| Issue number | 3 |
| DOIs | |
| State | Published - May 1 2015 |
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Keywords
- Apoptosis
- HSP60
- Hypoxia/reoxygenation
- Nox2
- TLR2
- TLR4
ASJC Scopus subject areas
- Biochemistry
- Cell Biology
Cite this
TLR4 mutation and HSP60-induced cell death in adult mouse cardiac myocytes. / Heiserman, J. P.; Chen, L.; Kim, B. S.; Kim, S. C.; Tran, A. L.; Siebenborn, N.; Knowlton, Anne A.
In: Cell Stress and Chaperones, Vol. 20, No. 3, 01.05.2015, p. 527-535.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - TLR4 mutation and HSP60-induced cell death in adult mouse cardiac myocytes
AU - Heiserman, J. P.
AU - Chen, L.
AU - Kim, B. S.
AU - Kim, S. C.
AU - Tran, A. L.
AU - Siebenborn, N.
AU - Knowlton, Anne A
PY - 2015/5/1
Y1 - 2015/5/1
N2 - Extracellular (ex) HSP60 is increasingly recognized as an agent of cell injury. Previously, we reported that low endotoxin exHSP60 causes cardiac myocyte apoptosis. Our findings supported a role for Toll-like receptor (TLR) 4 in HSP60 mediated apoptosis. To further investigate the involvement of TLR4 in cardiac injury, we studied adult cardiac myocytes from C3H/HeJ (HeJ) mice, which have a mutant, nonfunctional TLR4, and compared the results with parallel studies using wild-type (WT) mice. Nuclear factor κB (NFκB) activation is an early step downstream of TLR4. NFκB was activated 1 h after treatment with HSP60 in WT, but not HeJ mouse myocytes. ExHSP60 caused apoptosis in cardiac myocytes from WT mice, but not in myocytes from the HeJ mutants. To further elucidate the importance of exHSP60 in cardiac myocyte injury, both WT and HeJ mutant isolated mouse adult cardiac myocytes were exposed to hypoxia/reoxygenation. Anti-HSP60 antibody treatment reduced apoptosis in the WT group, but had no effect on the HeJ mutant myocytes. Unexpectedly, necrosis was also decreased in the HeJ mutants. Necrosis after hypoxia/reoxygenation in WT cardiac myocytes was mediated in part by TLR2 and TLR4 through rapid activation of PKCα, followed by increased expression of Nox2, and this was ameliorated by blocking antibodies to TLR2/4. These studies provide further evidence that TLR4 mediates exHSP60-associated apoptosis and that exHSP60 has an important role in cardiac myocyte injury, both apoptotic and necrotic.
AB - Extracellular (ex) HSP60 is increasingly recognized as an agent of cell injury. Previously, we reported that low endotoxin exHSP60 causes cardiac myocyte apoptosis. Our findings supported a role for Toll-like receptor (TLR) 4 in HSP60 mediated apoptosis. To further investigate the involvement of TLR4 in cardiac injury, we studied adult cardiac myocytes from C3H/HeJ (HeJ) mice, which have a mutant, nonfunctional TLR4, and compared the results with parallel studies using wild-type (WT) mice. Nuclear factor κB (NFκB) activation is an early step downstream of TLR4. NFκB was activated 1 h after treatment with HSP60 in WT, but not HeJ mouse myocytes. ExHSP60 caused apoptosis in cardiac myocytes from WT mice, but not in myocytes from the HeJ mutants. To further elucidate the importance of exHSP60 in cardiac myocyte injury, both WT and HeJ mutant isolated mouse adult cardiac myocytes were exposed to hypoxia/reoxygenation. Anti-HSP60 antibody treatment reduced apoptosis in the WT group, but had no effect on the HeJ mutant myocytes. Unexpectedly, necrosis was also decreased in the HeJ mutants. Necrosis after hypoxia/reoxygenation in WT cardiac myocytes was mediated in part by TLR2 and TLR4 through rapid activation of PKCα, followed by increased expression of Nox2, and this was ameliorated by blocking antibodies to TLR2/4. These studies provide further evidence that TLR4 mediates exHSP60-associated apoptosis and that exHSP60 has an important role in cardiac myocyte injury, both apoptotic and necrotic.
KW - Apoptosis
KW - HSP60
KW - Hypoxia/reoxygenation
KW - Nox2
KW - TLR2
KW - TLR4
UR - http://www.scopus.com/inward/record.url?scp=84939997899&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84939997899&partnerID=8YFLogxK
U2 - 10.1007/s12192-015-0577-0
DO - 10.1007/s12192-015-0577-0
M3 - Article
C2 - 25716072
AN - SCOPUS:84939997899
VL - 20
SP - 527
EP - 535
JO - Cell Stress and Chaperones
JF - Cell Stress and Chaperones
SN - 1355-8145
IS - 3
ER -