Apoptosis induced by lipid-associated membrane proteins from Mycoplasma hyopneumoniae in a porcine lung epithelial cell line with the involvement of caspase 3 and the MAPK pathway

Abstract

ABSTRACT. Lipid-associated membrane proteins (LAMPs) are important in the pathogenicity of the Mycoplasma genus of bacteria. We investigated whether Mycoplasma hyopneumoniae LAMPs have pathogenic potential by inducing apoptosis in a St. Jude porcine lung epithelial cell line (SJPL). LAMPs from a pathogenic strain of M. hyopneumoniae (strain 232) were used in the research. Our investigation made use of diamidino-phenylindole (DAPI) and acridine orange/ethidium bromide (AO/EB) staining, terminal dexynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) analysis, B. Ni et al. 11430©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (3): 11429-11443 (2015) and Annexin-V-propidium iodide staining. After LAMP treatment for 24 h, typical changes were induced, chromosomes were concentrated, apoptotic bodies were observed, the 3'-OH groups of cleaved genomes were exposed, and the percentage of apoptotic cells reached 36.5 ± 11.66%. Caspase 3 and caspase 8 were activated and cytochrome c (cyt c) was released from the mitochondria into the cytoplasm; poly ADP ribose polymerase (PARP) was digested into two fragments; p38 mitogen-activated protein kinase (MAPK) was phosphorylated; and the expression of pro-apoptosis protein Bax increased while the antiapoptosis protein Bcl-2 decreased. LAMPs also stimulated SJPL cells to produce nitric oxide (NO) and superoxide. This study demonstrated that LAMPs from M. hyopneumoniae can induce apoptosis in SJPL cells through the activation of caspase 3, caspase 8, cyt c, Bax, and p38 MAPK, thereby contributing to our understanding of the pathogenesis of M. hyopneumoniae, which should improve the treatment of M. hyopneumoniae infections.

Mycoplasmalipoproteins are major determinants of neutrophil extracellular trap formation

“…Lipoproteins play a central role in the pathogenesis of mycoplasmosis (Browning et al ., ). Surface lipoproteins of mycoplasmas interact with the host during infection and influence strain virulence (Szczepanek et al ., ) by promoting cytoadhesion (Sachse et al ., ; Boesen et al ., ; Thomas et al ., ; May and Brown, ; Xiong et al ., ), apoptosis (Ni et al ., ), host DNA digestion (Cacciotto et al ., ) and trafficking of nutrients and metabolites (Schmidt et al ., ; Cacciotto et al ., ). Furthermore, Mycoplasma lipoproteins play a pivotal role both in inducing adaptive host immune responses to infection and promoting evasion of this response, particularly by generating dramatic levels of antigenic variation on the bacterial cell surface (Cacciotto et al ., ; Nouvel et al ., ; Browning et al ., ).…”

Update onMycoplasma hyopneumoniaeinfections in pigs: Knowledge gaps for improved disease control

“…Cell‐surface lipoproteins, alternatively called lipid‐associated membrane proteins (LAMP), have also been found to be implicated in apoptosis. Whole membrane lipoprotein fractions were shown to induce apoptosis via caspases 3 and 8 activation in vitro in various cell types, including porcine peripheral blood mononuclear cells (PBMC; Bai et al., ; Ni et al., ). Furthermore, LAMPs activate production of nitric oxide (NO) and reactive oxygen species (ROS) in the host cell.…”

Knockdown of GluA2 induces apoptosis in non-small-cell lung cancer A549 cells through the p53 signaling pathway

“…Cellular morphological changes were subsequently examined using fluorescence microscopy; live cells were stained green, apoptotic cells, yellow and necrotic cells, red. The percentage of apoptotic cells was calculated using the following formula: Apoptotic rate (%)=(number of apoptotic cells/total number of cells)x100, as previously described (17,18).…”