METHODS: The hESCs were differentiated into neural stem cells (NSCs), and NSC-DECM was extracted from confluent monolayers of NSCs through treatment with deionized water. DFSCs seeded on NSC-DECM, Geltrex, and tissue culture polystyrene (TCPS) were subjected to neural induction during a period of 21 days. Expression of early/intermediate (Musashi1, PAX6, NSE, and βIII-tubulin) and mature/late (NGN2, NeuN, NFM, and MASH1) neural markers by DFSCs was analyzed at the 7-, 14-, and 21-day time points with quantitative real-time polymerase chain reaction. Immunocytochemistry for detection of βIII-tubulin, PAX6, and NGN2 expression by DFSCs on day 7 of neural induction was also carried out.
RESULTS: Quantitative RT-PCR showed that expression of PAX6, Musashi1, βIII-tubulin, NSE, NGN2, and NFM by DFSCs was enhanced on NSC-DECM versus either the Geltrex or TCPS groups. Immunocytochemistry showed that DFSCs in the NSC-DECM group displayed more intense staining for βIII-tubulin, PAX6, and NGN2 expression, together with more neurite outgrowths and elongated morphology, as compared with either Geltrex or TCPS.
CONCLUSIONS: DECM derived from neurogenesis of hESCs can enhance the neurogenic potential of DFSCs.
MATERIALS AND METHODS: Fresh specimens of P. australis were freeze-dried and subjected to ethanol extraction. The ethanol extract (PAEE) was evaluated for its protective effects against 1 µg/ml LPS-stimulated neuroinflammation in BV2 microglial cells.
RESULTS: LPS reduced the viability of BV2 microglia cells and increased the levels of nitric oxide (NO), prostaglandin E2 (PGE2), intracellular reactive oxygen species (ROS), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). However, the neuroinflammatory response was reversed by 0.5-2.0 mg/ml PAEE in a dose-dependent manner. Analysis of liquid chromatography-mass spectrometry (LC-MS) of PAEE subfractions revealed five compounds; methyl α-eleostearate, ethyl α-eleostearate, niacinamide, stearamide, and linoleic acid.
CONCLUSION: The protective effects of PAEE against LPS-stimulated neuroinflammation in BV2 microglial cells were found to be mediated by the suppression of excess levels of intracellular ROS and pro-inflammatory mediators and cytokines, denoting the protective role of P. australis in combating continuous neuroinflammation. Our findings support the use of P. australis as a possible therapeutic for neuroinflammatory and neurodegenerative diseases.
METHODS: Animals subjected to chronic restraint stress were given 4 weeks HE treatment. Animals were then screened for anxiety and depressive-like behaviours. Gene and protein assays, as well as histological analysis were performed to probe the role of neurogenesis in mediating the therapeutic effect of HE. Temozolomide was administered to validate the neurogenesis-dependent mechanism of HE.
RESULTS: The results showed that 4 weeks of HE treatment ameliorated depressive-like behaviours in mice subjected to 14 days of restraint stress. Further molecular assays demonstrated the 4-week HE treatment elevated the expression of several neurogenesis-related genes and proteins, including doublecortin, nestin, synaptophysin, brain-derived neurotrophic factor (BDNF), tropomyosin receptor kinase B (TrkB), phosphorylated extracellular signal-regulated kinase, and phosphorylated cAMP response element-binding protein (pCREB). Increased bromodeoxyuridine-positive cells were also observed in the dentate gyrus of the hippocampus, indicating enhanced neurogenesis. Neurogenesis blocker temozolomide completely abolished the antidepressant-like effects of HE, confirming a neurogenesis-dependent mechanism. Moreover, HE induced anti-neuroinflammatory effects through reducing astrocyte activation in the hippocampus, which was also abolished with temozolomide administration.
CONCLUSION: HE exerts antidepressant effects by promoting neurogenesis and reducing neuroinflammation through enhancing the BDNF-TrkB-CREB signalling pathway.