Danggui-Shaoyao-San Promotes Amyloid-ß Clearance through Regulating Microglia Polarization via Trem2 in BV2 Cells.

BACKGROUND: Alzheimer's disease (AD) is a chronic neurodegenerative brain disorder currently without satisfactory therapeutic treatments. Triggering receptors expressed on a myeloid cells-2 (Trem2) gene mutation has been reported as a powerful AD risk factor that induces Trem2 gene deletion aggravated microglia disfunction and Amyloid-ß (Aß) aggregation in the brain. The traditional Chinese medicine (TCM) formula Danggui-Shaoyao-San (DSS) has shown therapeutic effect on alleviating the symptoms of AD. However, the neuroprotective effect and underlying mechanism of DSS against AD is still far from fully understood. METHODS: Double-label immunofluorescence and Western blotting were employed to evaluate the different polarization states of mouse BV2 microglial (BV2) cells after lipopolysaccharide (LPS) or interleukin (IL)-4 treatment. Trem2 over-expression lentiviral vector and Trem2 siRNA were used respectively to evaluate the effect of Trem2 on microglia polarization via detecting the proteins expression of iNOS and arginase1 (Arg1) by Western blotting while the Aß-scavenging capacity of BV2 cells was assessed by flow cytometry. Cell counting kit-8 (CCK8) assay was performed to assess the effect of DSS on the viability of BV2 cells. Flow cytometry was used to investigate the effect of DSS on the Aß-scavenging capacity of BV2 cells treated with corresponding concentration of DSS-containing serum. Protein of Trem2 and the gene expression of the M1 or M2 phenotype in BV2 cells treated with DSS after Trem2 over-expression or silence were detected by Western blot and RT-qPCR, respectively. RESULTS: In vitro experiments. DSS exhibited anti-inflammatory and neuroprotective functions. It was found that Trem2 had an effect on inducing a shift of M1 microglia towards the M2 phenotype and enhanced the Aß-scavenging capacity of BV2 cells, further that DSS administration relieved inflammation by engulfing Aß through the activities of Trem2. Importantly, DSS treatment effectively increased the Aß-scavenging capacity of BV2 cells through accelerating the shift of M1 microglia towards an M2 phenotype via increasing Trem2 expression. CONCLUSIONS: Results demonstrated that DSS promoted the clearance of Aß through the regulation of microglia polarization via increased expression of Trem2 in BV2 cells.

Fo-Shou-San Ameliorates Chronic Cerebral Hypoperfusion-Induced Cognitive Impairment in Mice by Regulating NRF2/HO-1 Pathway Against Ferroptosis.

BACKGROUND: Fo-Shou-San (FSS) is a traditional Chinese medicine (TCM) decoction that can effectively treat vascular dementia (VD). In the face of unclear pharmacological mechanisms, we set out to validate that FSS treats chronic cerebral hypoperfusion (CCH)-induced cognitive impairment in mice. METHODS: CCH animal model caused by permanent right unilateral common carotid arteries occlusion (rUCCAO) was established to verify that FSS could treat subcortical ischemic vascular dementia (SIVD). We performed novel object recognition test and Morris water maze test, observed morphological changes via HE and Nissl staining, and detected hippocampus apoptosis by TUNEL staining and oxidative stress by biochemical assays. Ferroptosis-related markers and NRF2/HO-1 signaling-related expressions were examined via qPCR and immunofluorescence staining. RESULTS: We found that FSS ameliorated cognitive disorders, and lessened oxidative stress by decreasing MDA and GSH-PX while increasing the reduced glutathione (GSH)/oxidized glutathione disulfide (GSSG) ratio, which are associated with ferroptosis. Additionally, FSS reduced expression of SLC7A11, GPX4, ROX and 4HNE, as vital markers of ferroptosis. Further, FSS regulated NRF2/HO-1 signaling by downregulating NRF2 and HO-1. CONCLUSIONS: Our study suggests that FSS may ameliorate chronic cerebral hypoperfusion-induced cognitive deficits through regulation of the NRF2/HO-1 pathway against ferroptosis. Taken together, our study highlights the neuroprotective efficacy of FSS.