Activation of Autophagy Pathway Suppresses the Expression of iNOS, IL6 and Cell Death of LPS-Stimulated Microglia Cells.

Microglia play a role in maintaining and resolving brain tissue homeostasis. In pathological conditions, microglia release pro-inflammatory cytokines and cytotoxic factors, which aggravate the progression of neurodegenerative diseases. Autophagy pathway might be involved in the production of pro-inflammatory cytokines and cytotoxic factors in microglia, though details of the mechanism remain largely unknown. In the present study, we examined the role of the autophagy pathway in activated BV2 microglia cells. In BV2 cells, rapamycin treatment activated the formation of anti-LC3-labeled autophagosomes, whereas the ATG5 depletion using siRNA-ATG5 prevented the formation of LC3-labeled autophagosomes, indicating that BV2 cells exhibit an active classical autophagy system. When treated with LPS, BV2 cells expressed an increase of anti-LC3-labeled dots. The levels of LC3-labeled dots were not suppressed, instead tended to be enhanced, by the inhibition of the autophagy pathway with siRNA-ATG5 or wortmannin, suggesting that LPS-induced LC3-labeled dots in nature were distinct from the typical autophagosomes. The levels of LPS-induced expression of iNOS and IL6 were suppressed by treatment with rapamycin, and conversely, their expressions were enhanced by siRNA-ATG5 treatment. Moreover, the activation of the autophagy pathway using rapamycin inhibited cell death of LPS-stimulated microglia. These results suggest that although microglia possess a typical autophagy pathway, the glial cells express a non-typical autophagy pathway in response to LPS, and the activation of the autophagy pathway suppresses the expression of iNOS and IL6, and the cell death of LPS-stimulated microglia.

Oriental medicine Jangwonhwan reduces Abeta(1-42) level and beta-amyloid deposition in the brain of Tg-APPswe/PS1dE9 mouse model of Alzheimer disease.

ETHNOPHARMACOLOGICAL RELEVANCE: Jangwonhwan, a boiled extract of 12 medicinal plants/mushroom including Korean red ginseng (Panax ginseng C.A. Meyer), has been prescribed for patients with cognitive dysfunction and are believed to induce brain activity enhancement, provide light sedation, and facilitate sound sleep. AIM OF THE STUDY: The present study was carried out to investigate whether Jangwonhwan has a beneficial effect on the brain of Alzheimer disease. MATERIALS AND METHODS: The transgenic mice of Alzheimer disease, Tg-APPswe/PS1dE9, were fed a modified recipe of Jangwonhwan consisting of a boiled extract of 7 herbs/mushroom (called LMK02-Jangwonhwan) at 400mg/kg/day of dose for 3 months from 4.5 months of age. Immunohistological and ELISA analyses were used to assess the Abeta accumulation and plaque deposition in the brain. Other in vitro and in vivo works were performed to understand the underlying mechanism. RESULTS: LMK02-Jangwonhwan notably reduced Abeta(1-42) and Abeta(1-40) levels, concomitantly with a reduction of plaque deposition, in the brain of Tg-APPswe/PS1dE9 mice. LMK02-Jangwonhwan partially suppressed oxidative stress accumulation, and prevented the down-regulation of phospho-CREB and calbindin typically seen in the hippocampus of AD-like brains. In vitro study with SH-SY5Y neuroblastoma cells showed that LMK02-Jangwonhwan inhibited oxidative stress and Abeta-induced neurotoxicity. CONCLUSION: The present study suggests that LMK02-Jangwonhwan confers a therapeutic potential to ameliorate AD-like pathology in the brain of Tg-APPswe/PS1dE9 mice.