title: Role of Toll like receptor 4 signaling pathway in the secondary damage induced by experimental spinal cord injury.
abstract: Toll-like receptors (TLRs) are signaling receptors in the innate immune system that is specific immunologic response to systemic bacterial infection and injury. TLRs contribute to the initial induction of neuroinflammation in the CNS. In spinal cord injury (SCI) intricate immune cell interactions are triggered, typically consisting of a staggered multiphasic immune cell response, which can become deregulated. The present study aims to evaluate the role of TLR4 signaling pathway in the development of secondary damage in a mouse model of SCI using TLR4-deficient (TLR4-KO) mice such as C57BL/10ScNJ and C3H/HeJ mice. We evaluated behavioral changes, histological, immunohistochemistry and molecular assessment in TLR4-KO after SCI. SCI was performed on TLR4-KO and wild-type (WT) mice by the application of vascular clips (force of 24g) to the dura via a four-level T5-T8 laminectomy. Mice were sacrificed at 24h after SCI to evaluate the various parameters. SCI TLR4 KO mice developed severer hind limb motor dysfunction and neuronal death by histological evaluation, myeloid differentiation primary response 88 (Myd88) expression as well as an increase in nuclear factor NF-κB activity, tumor necrosis factor (TNF)-α and interleukin (IL)-1β levels, glial fibrillary acidic protein (GFAP), microglia marker (CD11β), inducible nitric oxide synthases (iNOS), poly-ADP-ribose polymerase (PARP) and nitrotyrosine expression compared to WT mice. Moreover, the absence of TLR4 also caused a decrease in phosphorylated interferon regulatory transcription factor (p-IRF3) and interferon (IFN-β) release. In addition, SCI TLR4 KO mice showed in spinal cord tissues a more pronounced up-regulation of Bax and a down-regulation of Bcl-2 compared to SCI WT mice. Finally, we clearly demonstrated that TLR4 is important for coordinating post-injury sequel and in regulating inflammation after SCI.
authors.affiliation: Department of Biological and Environmental Sciences, University of Messina, Viale Ferdinando Stagno D'Alcontres, Messina 31-98166, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Impellizzeri
authors.affiliation: Department of Biological and Environmental Sciences, University of Messina, Viale Ferdinando Stagno D'Alcontres, Messina 31-98166, Italy.
authors.forename: Akbar
authors.initials: A
authors.lastname: Ahmad
authors.affiliation: Department of Biological and Environmental Sciences, University of Messina, Viale Ferdinando Stagno D'Alcontres, Messina 31-98166, Italy.
authors.forename: Rosanna
authors.initials: R
authors.lastname: Di Paola
authors.affiliation: Department of Biological and Environmental Sciences, University of Messina, Viale Ferdinando Stagno D'Alcontres, Messina 31-98166, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Campolo
authors.affiliation: Department of Drug Sciences and Health Products, University of Messina, SS. Annunziata, Messina 98168, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Navarra
authors.affiliation: Department of Biological and Environmental Sciences, University of Messina, Viale Ferdinando Stagno D'Alcontres, Messina 31-98166, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Esposito
authors.affiliation: Department of Biological and Environmental Sciences, University of Messina, Viale Ferdinando Stagno D'Alcontres, Messina 31-98166, Italy; Manchester Biomedical Research Centre, Manchester Royal Infirmary, University of Manchester, UK. Electronic address: salvatore.cuzzocrea@unime.it.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Cuzzocrea
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000276:immunology; D039481:CD11b Antigen / Q000096:biosynthesis; D005786:Gene Expression Regulation; D005904:Glial Fibrillary Acidic Protein; D006614:Hindlimb / Q000473:pathology; D007249:Inflammation / Q000276:immunology*; D050838:Interferon Regulatory Factor-3 / Q000378:metabolism; D016899:Interferon-beta / Q000378:metabolism; D053583:Interleukin-1beta / Q000096:biosynthesis; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D053594:Myeloid Differentiation Factor 88 / Q000096:biosynthesis; D009419:Nerve Tissue Proteins / Q000096:biosynthesis; D015213:Neuroimmunomodulation / Q000276:immunology; D020556:Neutrophil Infiltration / Q000235:genetics / Q000276:immunology; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis; D011065:Poly(ADP-ribose) Polymerases / Q000096:biosynthesis; D015398:Signal Transduction / Q000276:immunology*; D013119:Spinal Cord Injuries / Q000276:immunology*; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000276:immunology*; D051996:Transcription Factor RelA / Q000096:biosynthesis; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D051028:bcl-2-Associated X Protein / Q000096:biosynthesis
chemical_list: D039481:CD11b Antigen; D005904:Glial Fibrillary Acidic Protein; C587672:IL1B protein, mouse; D050838:Interferon Regulatory Factor-3; D053583:Interleukin-1beta; C494233:Irf3 protein, mouse; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D009419:Nerve Tissue Proteins; C498144:Rela protein, mouse; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D051028:bcl-2-Associated X Protein; C528900:glial fibrillary astrocytic protein, mouse; D016899:Interferon-beta; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D011065:Poly(ADP-ribose) Polymerases
keywords: Apoptosis; MyD88; Nuclear factor-κB; Spinal cord injury; Toll-like receptor-4