Abstract
Cardiac fibroblasts contribute to multiple aspects of myocardial function and pathophysiology. The pathogenetic relevance of cytokine production by these cells under hypoxia, however, remains unexplored. With the use of an in vitro cell culture model, this study evaluated cytokine production by hypoxic cardiac fibroblasts and examined two distinct effects of hypoxic fibroblast-conditioned medium (HFCM) on cardiac myocytes and fibroblasts. Hypoxia caused a marked increase in the production of tumor necrosis factor (TNF)-α by cardiac fibroblasts. HFCM significantly enhanced the susceptibility of cardiac myocytes to reactive oxygen species (ROS)-induced mitochondrial permeability transition (MPT), determined by high-precision confocal line-scan imaging following controlled, photoexcitation-induced ROS production within individual mitochondria. Furthermore, exposure of cardiac myocytes to HFCM for 5 h led to loss of viability, as evidenced by change in morphology and annexin staining. HFCM also decreased DNA synthesis in cardiac fibroblasts. Normoxic fibroblast-conditioned medium spiked with TNF-α at 200 pg/ml, a concentration comparable to that in HFCM, promoted loss of myocyte viability and decreased DNA synthesis in cardiac fibroblasts. These effects of HFCM are similar to the reported effects of hypoxia per se on these cell types, showing that hypoxic fibroblast-derived factors may amplify the distinct effects of hypoxia on cardiac cells. Importantly, because both hypoxia and oxidant stress prevail in a setting of ischemia and reperfusion, the effects of soluble factors from hypoxic fibroblasts on the MPT-ROS threshold and viability of myocytes may represent a novel paracrine mechanism that could exacerbate ischemia-reperfusion injury to cardiomyocytes.
| Original language | English (US) |
|---|---|
| Journal | American Journal of Physiology - Heart and Circulatory Physiology |
| Volume | 294 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jun 2008 |
| Externally published | Yes |
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Keywords
- Apoptosis
- Cardiac fibroblasts
- Cardiac myocyte viability
- Fibroblast proliferation
- Fibroblast-conditioned medium
- Hypoxia
- Mitochondrial permeability transition-reactive oxygen species threshold
- Necrosis
- Tumor necrosis factor-α
ASJC Scopus subject areas
- Physiology
- Physiology (medical)
- Cardiology and Cardiovascular Medicine
Cite this
Paracrine effects of hypoxic fibroblast-derived factors on the MPT-ROS threshold and viability of adult rat cardiac myocytes. / Shivakumar, K.; Sollott, S. J.; Sangeetha, M.; Sapna, S.; Ziman, B.; Wang, S.; Lakatta, Edward.
In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 294, No. 6, 06.2008.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Paracrine effects of hypoxic fibroblast-derived factors on the MPT-ROS threshold and viability of adult rat cardiac myocytes
AU - Shivakumar, K.
AU - Sollott, S. J.
AU - Sangeetha, M.
AU - Sapna, S.
AU - Ziman, B.
AU - Wang, S.
AU - Lakatta, Edward
PY - 2008/6
Y1 - 2008/6
N2 - Cardiac fibroblasts contribute to multiple aspects of myocardial function and pathophysiology. The pathogenetic relevance of cytokine production by these cells under hypoxia, however, remains unexplored. With the use of an in vitro cell culture model, this study evaluated cytokine production by hypoxic cardiac fibroblasts and examined two distinct effects of hypoxic fibroblast-conditioned medium (HFCM) on cardiac myocytes and fibroblasts. Hypoxia caused a marked increase in the production of tumor necrosis factor (TNF)-α by cardiac fibroblasts. HFCM significantly enhanced the susceptibility of cardiac myocytes to reactive oxygen species (ROS)-induced mitochondrial permeability transition (MPT), determined by high-precision confocal line-scan imaging following controlled, photoexcitation-induced ROS production within individual mitochondria. Furthermore, exposure of cardiac myocytes to HFCM for 5 h led to loss of viability, as evidenced by change in morphology and annexin staining. HFCM also decreased DNA synthesis in cardiac fibroblasts. Normoxic fibroblast-conditioned medium spiked with TNF-α at 200 pg/ml, a concentration comparable to that in HFCM, promoted loss of myocyte viability and decreased DNA synthesis in cardiac fibroblasts. These effects of HFCM are similar to the reported effects of hypoxia per se on these cell types, showing that hypoxic fibroblast-derived factors may amplify the distinct effects of hypoxia on cardiac cells. Importantly, because both hypoxia and oxidant stress prevail in a setting of ischemia and reperfusion, the effects of soluble factors from hypoxic fibroblasts on the MPT-ROS threshold and viability of myocytes may represent a novel paracrine mechanism that could exacerbate ischemia-reperfusion injury to cardiomyocytes.
AB - Cardiac fibroblasts contribute to multiple aspects of myocardial function and pathophysiology. The pathogenetic relevance of cytokine production by these cells under hypoxia, however, remains unexplored. With the use of an in vitro cell culture model, this study evaluated cytokine production by hypoxic cardiac fibroblasts and examined two distinct effects of hypoxic fibroblast-conditioned medium (HFCM) on cardiac myocytes and fibroblasts. Hypoxia caused a marked increase in the production of tumor necrosis factor (TNF)-α by cardiac fibroblasts. HFCM significantly enhanced the susceptibility of cardiac myocytes to reactive oxygen species (ROS)-induced mitochondrial permeability transition (MPT), determined by high-precision confocal line-scan imaging following controlled, photoexcitation-induced ROS production within individual mitochondria. Furthermore, exposure of cardiac myocytes to HFCM for 5 h led to loss of viability, as evidenced by change in morphology and annexin staining. HFCM also decreased DNA synthesis in cardiac fibroblasts. Normoxic fibroblast-conditioned medium spiked with TNF-α at 200 pg/ml, a concentration comparable to that in HFCM, promoted loss of myocyte viability and decreased DNA synthesis in cardiac fibroblasts. These effects of HFCM are similar to the reported effects of hypoxia per se on these cell types, showing that hypoxic fibroblast-derived factors may amplify the distinct effects of hypoxia on cardiac cells. Importantly, because both hypoxia and oxidant stress prevail in a setting of ischemia and reperfusion, the effects of soluble factors from hypoxic fibroblasts on the MPT-ROS threshold and viability of myocytes may represent a novel paracrine mechanism that could exacerbate ischemia-reperfusion injury to cardiomyocytes.
KW - Apoptosis
KW - Cardiac fibroblasts
KW - Cardiac myocyte viability
KW - Fibroblast proliferation
KW - Fibroblast-conditioned medium
KW - Hypoxia
KW - Mitochondrial permeability transition-reactive oxygen species threshold
KW - Necrosis
KW - Tumor necrosis factor-α
UR - http://www.scopus.com/inward/record.url?scp=49249137984&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=49249137984&partnerID=8YFLogxK
U2 - 10.1152/ajpheart.91443.2007
DO - 10.1152/ajpheart.91443.2007
M3 - Article
C2 - 18408121
AN - SCOPUS:49249137984
VL - 294
JO - American Journal of Physiology
JF - American Journal of Physiology
SN - 0363-6135
IS - 6
ER -