Inflammatory neurodegeneration induced by lipoteichoic acid from Staphylococcus aureus is mediated by glia activation, nitrosative and oxidative stress, and caspase activation.
In this study we investigated the mechanisms of neuronal cell death induced by lipoteichoic acid (LTA) and muramyl dipeptide (MDP) from Gram-positive bacterial cell walls using primary cultures of rat cerebellum granule cells (CGCs) and rat cortical glial cells (astrocytes and microglia). LTA (+/- MDP) from Staphylococcus aureus induced a strong inflammatory response of both types of glial cells (release of interleukin-1beta, tumour necrosis factor-alpha and nitric oxide). The death of CGCs was caused by activated glia because in the absence of glia (treatment with 7.5 microm cytosine-d-arabinoside to inhibit non-neuronal cell proliferation) LTA + MDP did not cause significant cell death (less than 20%). In addition, staining with rhodamine-labelled LTA confirmed that LTA was bound only to microglia and astrocytes (not neurones). Neuronal cell death induced by LTA (+/- MDP)-activated glia was partially blocked by an inducible nitric oxide synthase inhibitor (1400 W; 100 microm), and completely blocked by a superoxide dismutase mimetic [manganese (III) tetrakis (4-benzoic acid)porphyrin chloride; 50 microm] and a peroxynitrite scavenger [5,10,15,20-tetrakis (4-sulfonatophenyl) porphyrinato iron (III); 100 microm] suggesting that nitric oxide and peroxynitrite contributed to LTA-induced cell death. Moreover, neuronal cell death was inhibited by selective inhibitors of caspase-3 (z-DEVD-fmk; 50 microm) and caspase-8 (z-Ile-Glu(O-Me)-Thr-Asp(O-Me) fluoromethyl ketone; 50 microm) indicating that they were involved in LTA-induced neuronal cell death.
Kinsner
Agnieszka
A
European Centre for the Validation of Alternative Methods (ECVAM), European Commission Joint Research Centre, Ispra, Italy.
Pilotto
Valentina
V
Deininger
Susanne
S
Brown
Guy C
GC
Coecke
Sandra
S
Hartung
Thomas
T
Bal-Price
Anna
A
D000119:Acetylmuramyl-Alanyl-Isoglutamine / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D020169:Caspases / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003561:Cytarabine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004660:Encephalitis / Q000209:etiology / Q000473:pathology; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007375:Interleukin-1 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D037102:Lectins / Q000378:metabolism; D008070:Lipopolysaccharides; D008954:Models, Biological; D019636:Neurodegenerative Diseases / Q000139:chemically induced / Q000150:complications / Q000473:pathology*; D009457:Neuroglia / Q000187:drug effects / Q000502:physiology*; D009573:Nitrites / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology*; D051381:Rats; D017472:Receptors, Interleukin-1 / Q000378:metabolism; D013211:Staphylococcus aureus / Q000737:chemistry*; D013682:Teichoic Acids; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D004791:Enzyme Inhibitors; D005904:Glial Fibrillary Acidic Protein; D007375:Interleukin-1; D015850:Interleukin-6; D037102:Lectins; D008070:Lipopolysaccharides; D009573:Nitrites; D017472:Receptors, Interleukin-1; D013682:Teichoic Acids; D014409:Tumor Necrosis Factor-alpha; D003561:Cytarabine; D000119:Acetylmuramyl-Alanyl-Isoglutamine; C009900:lipoteichoic acid; D020169:Caspases