Mitochondrial localization of non-histone protein HMGB1 during human endothelial cell-Toxo infection

Cell Biol Int. 2007 Sep 7; [Epub ahead of print]

Mitochondrial localization of non-histone protein HMGB1 during human endothelial cell-Toxoplasma gondii infection

Stumbo AC, Cortez E, Rodrigues CA, Henriques MD, Porto LC, Barbosa HS, Carvalho L

Laboratório Cultura de Células, Departamento de Histologia e Embriologia, Instituto de Biologia, Universidade do Estado do Rio de Janeiro, UERJ, Av. Prof. Manoel de Abreu 444, 3° andar, 20550-170 Rio de Janeiro, RJ, Brazil.

Toxoplasma gondii is an obligate intracellular pathogen, replicating only within a specialized membrane-bounded cytoplasmic vacuole, the parasitophorous vacuole (PV), which interacts with host cell mitochondria. High mobility group box 1 (HMGB1), a known nuclear transcription factor, also may be involved in pathological conditions, whose function is to signal tissue damage. Using confocal microscopy, we have investigated the localization of HMGB1 and the mitochondria performance during interaction between human umbilical vein endothelial cells (HUVEC) and Toxoplasma. Immunofluorescence showed HMGB1 localization in HUVEC tubular mitochondria stained with Mito Tracker (MT). At 2h post-infection, MT labeled spherical structures scattered throughout the cytoplasm and HMGB1 were still present. After 24h of infection, long and tubular structures were localized around PVs and were double labeled by MT and HMGB1, suggesting a structural reorganization of the mitochondria over a long period of infection. For the first time, these results show there is HMGB1 in HUVEC mitochondria and that this protein could be playing a part in mitochondrial DNA events which are important for fission and fusion processes reported here during HUVEC-T. gondii infection.

PMID: 17936030 [PubMed - as supplied by publisher]