@article {Antonella:1 September 2004:0305-7453:603, author = "Antonella Lupetti", author = "Carlo P. J. M. Brouwer", author = "Heleen E. C. Dogterom-Ballering", author = "Sonia Senesi", author = "Mario Campa", author = "Jaap T. van Dissel", author = "Peter H. Nibbering", title = "Release of calcium from intracellular stores and subsequent uptake by mitochondria are essential for the candidacidal activity of an N-terminal peptide of human lactoferrin", journal = "Journal of Antimicrobial Chemotherapy", volume = "54", year = "1 September 2004", abstract = "Objectives: Earlier studies showed that mitochondrial damage is a hallmark of the candidacidal activity of an N-terminal peptide of human lactoferrin, further referred to as hLF(1–11). Since uptake of Ca²⁺ by mitochondria may be essential for their activation, the aim of this study was to define the role of Ca²⁺ in killing of Candida albicans by the hLF(1–11) peptide.

Methods: The effect of compounds interfering with Ca²⁺ homeostasis on the hLF(1–11)-induced candidacidal activity, changes in mitochondrial membrane potential, and reactive oxygen species production were evaluated using a killing assay, rhodamine 123 staining, and 2 prime

-dichlorofluorescein diacetate, respectively. The increase in cellular Ca²⁺ content was measured using ⁴⁵Ca²⁺.

Results: Our results revealed that Ruthenium Red, which inhibits the mitochondrial Ca²⁺-uniporter and the voltage-sensitive Ca²⁺ release from internal stores, blocked (P<0.05) the hLF(1–11)-induced candidacidal activity as well as changes in the membrane potential of mitochondria, and reactive oxygen species production. Oxalate, which precipitates Ca²⁺ in intracellular organelles, decreased (P<0.05) the peptide-induced changes in the membrane potential of mitochondria, reactive oxygen species production, and candidacidal activity. Furthermore, the Ca²⁺ ionophore ionomycin combined with high CaCl<inf>2</inf> concentrations enhanced the hLF(1–11)-induced candidacidal activity. Moreover, hLF(1–11) caused an influx of Ca²⁺ from the extracellular medium into C. albicans reaching a three-fold increase at 2 h, whereas no increase was found in unexposed cells. In agreement, the Ca²⁺-chelator EGTA blocked the peptide-induced candidacidal activity.

Conclusions: Ca²⁺ release from intracellular stores, probably through subsequent mitochondrial Ca²⁺ uptake, is essential for the hLF(1–11)-induced candidacidal activity.", pages = "603-608(6)", url = "http://www.ingentaconnect.com/content/oup/janmic/2004/00000054/00000003/art00603" doi = "doi:10.1093/jac/dkh385" }