Neuroprotective and mechanistic study of GJ-4 on okadaic acid-induced memory impairment in mice / 药学学报

GJ-4 is crocin enrichments extracted from Gardenia jasminoides J. Ellis, and our previous studies have shown that GJ-4 significantly improved learning and memory impairment induced by Aβ in mice. Herein, a memory deficit model was developed by injecting okadaic acid (OA) into the lateral ventricle of mice, and the neuroprotection and underlying mechanism of GJ-4 on neuronal injury caused by Tau hyperphosphorylation were investigated. The Animal Care & Welfare Committee, Institute of Materia Medica, CAMS & PUMC has approved all procedures (No.00000318). GJ-4 at different doses was intragastric administration to mice for 16 days. Step-down test and Morris water maze test showed that GJ-4 could significantly improve OA-induced memory impairment in mice, and reduced the loss of Nissl bodies in the hippocampus of mice. GJ-4 could also decrease the phosphorylation level of Tau protein at Ser396, Thr231 and Ser404 via increasing protein phosphatase 2A (PP2A) activity and inhibiting glycogen synthase kinase-3β (GSK-3β) activity. Besides, further researches indicated that GJ-4 could inhibit the level of oxidative stress in the brain of OA mice, reduce neuronal apoptosis and inhibit the neuroinflammation mediated by activation of astrocytes in the hippocampus of mice, and eventually achieve its effects in improving learning and memory impairment in mice. According to these findings, we anticipated that GJ-4 might be a potential therapeutic drug for Alzheimer's disease.

Lipopolysaccharide potentiates dopaminergic neuronal dysfunction in α-synuclein transgenic mice / 药学学报

Parkinson's disease (PD) is the most prevalent neurodegenerative disorder, with several risk factors contributing to the onset, such as aging, genetics, oxidative stress and neuroinflammation. There are several PD animals that mimics different risk factor. α-Synuclein mutation mice and systemic lipopolysaccharide (LPS) injection mice are two kinds of most common animal models that replicate genetic mutation and neuroinflammation, respectively. However, in these two animal models, the pathogenesis occurred after a long period of stimulation. In the present study, four-month-old α-synucleintransgenic mice (A53T) were intraperitoneally injected with LPS once a week for continuous 8 weeks to simulate the inflammatory response. The behavioral results showed that the time of mice staying on the rod and the performance score were markedly decreased, indicating motor dysfunction. Dopaminergic neuronal function also decreased. It was noted that the movement dysfunction and pathological changes were aggravated in LPS plus α-synuclein challenged mice compared with LPS or α-synuclein stimulated alone, suggesting that the double attack had synergistic effects. Mechanistic study demonstrated that LPS and α-synuclein combined challenge led to obvious neuroinflammatory response and apoptosis, which might contribute to motor and dopaminergic neuronal dysfunction. In addition, differential proteomic study showed that the expression of CD99L2 and COX7RP significantly increased in the midbrain of LPS plus α-synuclein challenged mice, which were closely related to inflammation and apoptosis, and might be involved in the pathogenesis of PD. In conclusion, the present study demonstrated that LPS could potentiate dopaminergic neuronal function in α-synuclein transgenic mice, which might be an ideal method to develop PD animal model.

Mechanism of Non-receptor Tyrosine Kinase Src Regulating Neuroinflammation Through Phosphatase and Tensin Homology Protein in Microglia / 中国医学科学院学报

Objective To investigate the mechanism of non-receptor tyrosine kinase Src regulating neuroinflammation through phosphatase and tensin homology protein(PTEN)in microglia. Methods BV2 cells were incubated with PTEN inhibitor bpv(HOpic)for 2 hours,and then added with lipopolysaccharide(LPS)to induce neuroinflammation,Western blot was performed to determine the expression of phosphorylated protein kinase B(Akt)to investigate the activity of PTEN. Enzyme-linked immunosorben assay(ELISA)was used to determine the release of tumor necrosis factor α(TNF-α)to assess neuroinflammation.After PTEN inhibitor or Src specific small interfering RNA was added,the change of neuroinflammation was evaluated to study the mechanism of Src regulating neuroinflammation. Results LPS induced significant neuroinflammation in BV2 cells,as indicated by significantly increased expression of p-Akt and release of TNF-α(P<0.001).The PTEN inhibitor signficantly increased Akt phosphorylation(P<0.05)and TNF-α release(P<0.001)in LPS-induced BV2 cells compared to simply LPS-induced cells.The Src small interfering RNA significantly decreased the release of TNF-α(P<0.001)and inhibited PTEN(P<0.001)and Akt(P<0.001)phosphorylation. Conclusion Src kinase may regulate neuroinflammtion response in BV2 cells by regulating the phosphorylation of PTEN.

The role of neuroinflammation-related regulatory targets in the treatment for Parkinson's disease / 药学学报

Parkinson's disease (PD) is a neurodegenerative disease characterized by the degeneration of dopaminergic neurons. The present therapeutic drugs for PD can only alleviate the patients' symptoms, but cannot prevent or delay progression of the disease. Great efforts have been made in the identification of new molecular targets that can prevent or delay the loss of dopaminergic neurons. Growing evidences support the key role of neuroinflammation in the pathogenesis of PD, featured by the activation of glial cells and many enzymes and receptors. This review will provide an overview of the enzymes and receptors closely related to neuroinflammation, which have a potential in the prevention or treatment of the disease.