Staphylococcus haemolyticus strains target mitochondria and induce caspase-dependent apoptosis of macrophages

Abstract

The aim of this study was to investigate the interaction of Staphylococcus haemolyticus strains with a macrophage cell line. Infection with the strains resulted in macrophage injury. All strains exhibited cytotoxic effects towards J774 cells. Moreover, the bacteria triggered apoptosis of the cells. The lowest apoptotic index did not exceed 21 %, whereas the highest reached 70 % at 24 h and 85 % at 48 h after infection. Incubation with the bacteria caused loss of mitochondrial membrane potential (ΔΨm) in macrophages. The pro-apoptotic activity of the strains was blocked by a pan-caspase inhibitor z-VAD-fmk, indicating the involvement of caspases in the bacteria-mediated cell death. We observed that the induction of macrophage apoptosis could constitute an important mechanism of pathogenesis by which S. haemolyticus strains evade host immune defences and cause disease.

Can apoptosis and necrosis coexist in ejaculated human spermatozoa during in vitro semen bacterial infection?

“…In our study, the ejaculated human spermatozoa had greater apoptotic and necrotic changes following treatment with B. ureolyticus and S. haemolyticus than with uropathogenic E. coli O75:HNT. The mechanism of pathogenesis with the S. haemolyticus strain is still poorly understood, although the depolarization of mitochondria and the induction of caspase-dependent apoptosis in macrophages after treatment with S. haemolyticus strains has recently been found [42]. Our present results suggest a similar pathogenicity of S. haemolyticus for ejaculated human sperm.…”

Multifactorial mechanisms of the pathogenesis of methicillin-resistant Staphylococcus hominis isolated from bloodstream infections

“…Adhesion and invasion ability were performed in a quantitative assay using the gentamicin/lysostaphin protection method, with modifications (Krzymińska et al 2012a, b, 2015). For the analysis of bacterial adhesion, the infected HeLa cells were lysed using 0.1% Triton X-100.…”

“…Two-fold dilutions (from 1:2 to 1:512) of supernatants were prepared, in phosphate buffered saline (PBS, Biomed). They were added to the HeLa cell monolayer and incubated for 24 h. The effect of extracellular toxins was expressed as a cytotoxic index and assessed as the reciprocal of the highest dilution of the culture filtrates, which produced a cytopathic effect that was observed under an inverted microscope (Krzymińska et al 2012a, b). As a negative control, cells treated with non-pathogenic E. coli K12C600 filtrate were used.…”

Connection of urethral microbiota with the semen quality and the concentration of endocrine disrupters in men semen

“…Связь условно-патогенной урогенитальной инфекции с качеством эякулята широко изучается в настоящее время с помощью полимеразной цепной реакции, хроматографии с масс-спектрометрией или высокопроизводительного секвенирования (next-generation sequencing) [2][3][4]. Хорошо известна роль условно-патогенных микроорганизмов в метаболизме ксенобиотиков [5,6], а также их способность вызывать гибель клеток, в частности апоптоз сперматозоидов [7][8][9]. Вместе с тем отсутствуют убедительные данные о том, при каких условиях условно-патогенная микрофлора урогенитального тракта способна оказывать влияние на качество эякулята и становиться причиной мужской субфертильности или инфертильности.…”