RESUMO
BACKGROUND: Excessive production of inflammatory mediators such as nitric oxide (NO) and proinflammatory cytokines like tumour necrosis factor-alpha (TNF-α) from activated microglia contributes to uncontrolled inflammation in neurodegenerative diseases. This study investigated the protective role of five endophytic extracts (HAB16R12, HAB16R13, HAB16R14, HAB16R18 and HAB8R24) against LPS-induced inflammatory events in vitro. These endophytic extracts were previously found to exhibit potent neuroprotective effect against LPS-challenged microglial cells. METHODS: The effects of these fungal endophytic extracts against nitric oxide (NO), CD40 phenotype and, pro- and anti-inflammatory cytokine production in lipopolysaccharide (LPS)-stimulated BV2 microglia cells were examined using commercially available assay kits, immunophenotyping and flow cytometry, respectively. RESULTS: Microglia pre-treated with the five endophytic extracts (0.1 mg/mL) reduced NO production without compromising cell viability. Whilst CD40 expression in LPS-stimulated microglia was not significantly different with or without the influence of endophytic extracts, expression of the proinflammatory cytokines, IL-6 and TNF-α in LPS-stimulated microglia was significantly (P < 0.05) inhibited by these endophytic extracts. CONCLUSIONS: The outcomes suggest that the neuroprotective effect of the fungal endophytic extracts is likely mediated through supression of neuroinflammation. To our knowledge, this is the first report of the effect of a fungal endophytic extract in controlling inflammation in BV2 microglia cells.
Assuntos
Anti-Inflamatórios/uso terapêutico , Citocinas/metabolismo , Endófitos/química , Fungos/química , Mediadores da Inflamação/metabolismo , Inflamação/tratamento farmacológico , Microglia/efeitos dos fármacos , Anti-Inflamatórios/farmacologia , Produtos Biológicos/farmacologia , Produtos Biológicos/uso terapêutico , Antígenos CD40/metabolismo , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cinnamomum/microbiologia , Inflamação/induzido quimicamente , Inflamação/metabolismo , Interleucina-6/metabolismo , Lipopolissacarídeos , Macrófagos/metabolismo , Microglia/metabolismo , NF-kappa B/metabolismo , Fármacos Neuroprotetores/farmacologia , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
BACKGROUND: BACE1 was found to be the major ß-secretase in neurons and its appearance and activity were found to be elevated in the brains of AD patients. Fungal endophytic extracts for BACE1 inhibitory activity and cytotoxicity against PC-12 (a rat pheochromocytoma with neuronal properties) and WRL68 (a non-tumorigenic human hepatic) were investigated. METHODS: Endophytes were isolated from plants collected from Kuala Pilah, Negeri Sembilan and the National Park, Pahang and the extracts were tested for BACE1 inhibition. For investigation of biological activity, the pure endophytic cultures were cultivated for 14 days on PDA plates at 28°C and underwent semipolar extraction with ethyl acetate. RESULTS: Of 212 endophytic extracts (1000 µg/ml), 29 exhibited more than 90% inhibition of BACE1 in the preliminary screening. Four extracts from isolates HAB16R13, HAB16R14, HAB16R18 and HAB8R24 identified as Cytospora rhizophorae were the most active with IC(50(BACE1)) values of less than 3.0 µg/ml. The most active extract HAB16R13 was shown to non-competitively inhibit BACE1 with K(i) value of 10.0 µg/ml. HAB16R13 was considered non-potent against PC-12 and WRL68 (IC(50(CT))) of 60.0 and 40.0 µg/ml, respectively). CONCLUSIONS: This first report on endophytic fungal extract with good BACE1 inhibitory activity demonstrates that more extensive study is required to uncover the potential of endophytes.