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Expression of endoplasmic reticulum chaperones in cardiac development.

Papp S, Zhang X, Szabo E, Michalak M, Opas M - Open Cardiovasc Med J (2008)

Bottom Line: We found stress related chaperones were more abundant in embryonic compared to adult hearts, indicating endoplasmic reticulum stress during normal cardiac development.In adult hearts, chaperones are less abundant but there are increased levels of ATF6alpha and ER stress-activated caspases.Thus, protein synthesis during embryonic development does not seem to be as intense a stress as is required for apoptosis that is found during postnatal remodelling.

View Article: PubMed Central - PubMed

Affiliation: Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.

ABSTRACT
To determine if cardiogenesis causes endoplasmic reticulum stress, we examined chaperone expression. Many cardiac pathologies cause activation of the fetal gene program, and we asked the reverse: could activation of the fetal gene program during development induce endoplasmic reticulum stress/chaperones? We found stress related chaperones were more abundant in embryonic compared to adult hearts, indicating endoplasmic reticulum stress during normal cardiac development. To determine the degree of stress, we investigated endoplasmic reticulum stress pathways during cardiogenesis. We detected higher levels of ATF6alpha, caspase 7 and 12 in adult hearts. Thus, during embryonic development, there is large protein synthetic load but there is no endoplasmic reticulum stress. In adult hearts, chaperones are less abundant but there are increased levels of ATF6alpha and ER stress-activated caspases. Thus, protein synthesis during embryonic development does not seem to be as intense a stress as is required for apoptosis that is found during postnatal remodelling.

No MeSH data available.


Related in: MedlinePlus

Detection of ATF6α in mouse heart tissues. . Western blotting of ATF6α reveals that the protein is more abundant in adult heart tissue, especially adult ventricular tissue, compared to embryonic heart tissues. Lane “+” refers to the positive control for ATF6α which was an extract from the thapsigargin treated mouse embryo fibroblasts as described in Materials in Methods.GAPDH was used as a loading control.E – embryonic day; A – adult; H – heart; At – atria; V – ventricles
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Figure 5: Detection of ATF6α in mouse heart tissues. . Western blotting of ATF6α reveals that the protein is more abundant in adult heart tissue, especially adult ventricular tissue, compared to embryonic heart tissues. Lane “+” refers to the positive control for ATF6α which was an extract from the thapsigargin treated mouse embryo fibroblasts as described in Materials in Methods.GAPDH was used as a loading control.E – embryonic day; A – adult; H – heart; At – atria; V – ventricles

Mentions: We could not detect eIF-2α protein,phospho-eIF-2α protein or cleaved XBP-1 mRNA (a cleavage product of IRE1) either during embryonic heart development or during adulthood (data not shown). We also performed Western blot analysis of ATF6α expression in mouse embryonic heart tissues. The expression of ATF6α remained unchanged during embryonic heart development and was slightly higher in adult tissues, especially in the adult ventricles (Fig. 5). It seems then, that there is not a great degree of ER stress within the developing mouse heart. We could not detect UPR activation in developing mouse hearts, but there seemed to be some degree of ATF6 induction in the adult heart. It can only be speculated on that such an induction may be due to cardiac remodelling. Further examinations need to be undertaken to determine the degree of such possible remodelling and to determine if it is normal or pathologic.


Expression of endoplasmic reticulum chaperones in cardiac development.

Papp S, Zhang X, Szabo E, Michalak M, Opas M - Open Cardiovasc Med J (2008)

Detection of ATF6α in mouse heart tissues. . Western blotting of ATF6α reveals that the protein is more abundant in adult heart tissue, especially adult ventricular tissue, compared to embryonic heart tissues. Lane “+” refers to the positive control for ATF6α which was an extract from the thapsigargin treated mouse embryo fibroblasts as described in Materials in Methods.GAPDH was used as a loading control.E – embryonic day; A – adult; H – heart; At – atria; V – ventricles
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2570582&req=5

Figure 5: Detection of ATF6α in mouse heart tissues. . Western blotting of ATF6α reveals that the protein is more abundant in adult heart tissue, especially adult ventricular tissue, compared to embryonic heart tissues. Lane “+” refers to the positive control for ATF6α which was an extract from the thapsigargin treated mouse embryo fibroblasts as described in Materials in Methods.GAPDH was used as a loading control.E – embryonic day; A – adult; H – heart; At – atria; V – ventricles
Mentions: We could not detect eIF-2α protein,phospho-eIF-2α protein or cleaved XBP-1 mRNA (a cleavage product of IRE1) either during embryonic heart development or during adulthood (data not shown). We also performed Western blot analysis of ATF6α expression in mouse embryonic heart tissues. The expression of ATF6α remained unchanged during embryonic heart development and was slightly higher in adult tissues, especially in the adult ventricles (Fig. 5). It seems then, that there is not a great degree of ER stress within the developing mouse heart. We could not detect UPR activation in developing mouse hearts, but there seemed to be some degree of ATF6 induction in the adult heart. It can only be speculated on that such an induction may be due to cardiac remodelling. Further examinations need to be undertaken to determine the degree of such possible remodelling and to determine if it is normal or pathologic.

Bottom Line: We found stress related chaperones were more abundant in embryonic compared to adult hearts, indicating endoplasmic reticulum stress during normal cardiac development.In adult hearts, chaperones are less abundant but there are increased levels of ATF6alpha and ER stress-activated caspases.Thus, protein synthesis during embryonic development does not seem to be as intense a stress as is required for apoptosis that is found during postnatal remodelling.

View Article: PubMed Central - PubMed

Affiliation: Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.

ABSTRACT
To determine if cardiogenesis causes endoplasmic reticulum stress, we examined chaperone expression. Many cardiac pathologies cause activation of the fetal gene program, and we asked the reverse: could activation of the fetal gene program during development induce endoplasmic reticulum stress/chaperones? We found stress related chaperones were more abundant in embryonic compared to adult hearts, indicating endoplasmic reticulum stress during normal cardiac development. To determine the degree of stress, we investigated endoplasmic reticulum stress pathways during cardiogenesis. We detected higher levels of ATF6alpha, caspase 7 and 12 in adult hearts. Thus, during embryonic development, there is large protein synthetic load but there is no endoplasmic reticulum stress. In adult hearts, chaperones are less abundant but there are increased levels of ATF6alpha and ER stress-activated caspases. Thus, protein synthesis during embryonic development does not seem to be as intense a stress as is required for apoptosis that is found during postnatal remodelling.

No MeSH data available.


Related in: MedlinePlus