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Hepatology. 2011 Jul;54(1):296-306. doi: 10.1002/hep.24367.

Mitochondrial calcium regulates rat liver regeneration through the modulation of apoptosis.

Author information

1
Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.

Abstract

Subcellular Ca(2+) signals control a variety of responses in the liver. For example, mitochondrial Ca(2+) (Ca(mit)(2+)) regulates apoptosis, whereas Ca(2+) in the nucleus regulates cell proliferation. Because apoptosis and cell growth can be related, we investigated whether Ca(mit)(2+) also affects liver regeneration. The Ca(2+)-buffering protein parvalbumin, which was targeted to the mitochondrial matrix and fused to green fluorescent protein, was expressed in the SKHep1 liver cell line; the vector was called parvalbumin-mitochondrial targeting sequence-green fluorescent protein (PV-MITO-GFP). This construct properly localized to and effectively buffered Ca(2+) signals in the mitochondrial matrix. Additionally, the expression of PV-MITO-GFP reduced apoptosis induced by both intrinsic and extrinsic pathways. The reduction in cell death correlated with the increased expression of antiapoptotic genes [B cell lymphoma 2 (bcl-2), myeloid cell leukemia 1, and B cell lymphoma extra large] and with the decreased expression of proapoptotic genes [p53, B cell lymphoma 2-associated X protein (bax), apoptotic peptidase activating factor 1, and caspase-6]. PV-MITO-GFP was also expressed in hepatocytes in vivo with an adenoviral delivery system. Ca(mit)(2+) buffering in hepatocytes accelerated liver regeneration after partial hepatectomy, and this effect was associated with the increased expression of bcl-2 and the decreased expression of bax.

CONCLUSION:

Together, these results reveal an essential role for Ca(mit)(2+) in hepatocyte proliferation and liver regeneration, which may be mediated by the regulation of apoptosis.

PMID:
21503946
PMCID:
PMC3125477
DOI:
10.1002/hep.24367
[Indexed for MEDLINE]
Free PMC Article

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