Hydroxy-safflor yellow A attenuates Aβ₁₋₄₂-induced inflammation by modulating the JAK2/STAT3/NF-κB pathway.

Beta-amyloid (Aβ)-mediated inflammation plays a critical role in the initiation and progression of Alzheimer׳s disease (AD). Anti-inflammatory treatment may provide therapeutic benefits. In this study, the effect of hydroxy-safflor yellow A (HSYA) on Aβ1-42-induced inflammation in AD mice was investigated and the underlying mechanisms were explored. Aβ1-42 was injected into bilateral hippocampi of mice to induce AD models in vivo. Spatial learning and memory of mice were investigated by the Morris water maze test. Activated microglia and astrocytes were examined by immunofluorescence staining for ionized calcium-binding adapter molecule-1 (Iba-1) and glial fibrillary acidic protein (GFAP). The mRNA of inflammatory cytokines were measured using real-time PCR. NF-κB p65 translocation was analyzed by western blotting and immunostaining. IκB and phosphorylation of JAK2 and STAT3 were tested by western blotting. The results showed that HSYA ameliorated the memory deficits in Aβ1-42-induced AD mice. HSYA suppressed Aβ1-42-induced activation of microglia and astrocytes and reduced the mRNA expression of pro-inflammatory mediators. HSYA up-regulated the JAK2/STAT3 pathway and inhibits the activation of NF-κB signaling pathways. Pharmacological inhibition of STAT3 by AG490 reversed the inactivation of p65 and anti-inflammatory effects of HSYA. In conclusion, these results suggest that HSYA protects Aβ1-42-induced AD model through inhibiting inflammatory response, which may involve the JAK2/STAT3/NF-κB pathway.

Zhang ZH ，Yu LJ ，Hui XC ，Wu ZZ ，Yin KL ，Yang H ，Xu Y ... -  《-》

Hydroxy-safflor yellow A inhibits neuroinflammation mediated by Aβ₁₋₄₂ in BV-2 cells.

Inflammation is an important contributor to the development of Alzheimer's disease (AD). Anti-inflammatory medication may offer promising treatment for AD. Hydroxy-safflor yellow A (HSYA), a chemical component of the safflower yellow pigments, has been reported to exert potent immunosuppressive effects. This study examined the anti-inflammatory effects of HSYA in Aβ₁₋₄₂-treated BV-2 microglia cells. The mRNA levels of IL-1β, IL-4, IL-10, TNF-α, COX-2 and iNOS were detected by real-time PCR. Western blotting was used to determine the protein expression of COX-2, TNF-α, iNOS, Janus Kinase 2 (JAK2), p-JAK2, signal transducers and activators of transcription 3 (STAT3) and p-STAT3. BV2-conditioned medium was used to treat SH-SY5Y cells and primary neuronal cells in indirect toxicity experiments. Cell viability and apoptosis were assessed using MTT assay and Annexin V/PI staining respectively. The results demonstrated that HSYA significantly reduced the expression of the pro-inflammatory mediators and inhibited Aβ₁₋₄₂-induced neuroinflammation. Moreover, HSYA protected primary cortical neurons and SH-SY5Y cells against microglia-mediated neurotoxicity. HSYA also enhanced the phosphorylation of JAK2/STAT3 pathway and inhibition of JAK2 by AG 490 attenuated the anti-inflammatory effects of HSYA. Overall, our findings suggested that HSYA inhibited Aβ₁₋₄₂-induced inflammation and conferred neuroprotection partially through JAK2/STAT3 pathway, indicating that HSYA could be a potential drug for the treatment of AD.

Zhang Z ，Wu Z ，Zhu X ，Hui X ，Pan J ，Xu Y ... -  《-》

Hydroxysafflor yellow A suppresses inflammatory responses of BV2 microglia after oxygen-glucose deprivation.

Inflammation is a pivotal pathological progress in the development of ischemic stroke. Modulating inflammatory cytokines released by microglia is thought to be a potential strategy for the treatment of ischemic stroke. Hydroxy-safflor yellow A (HSYA), a chemical component of the safflower yellow pigments, was reported to protect against brain injury in experimental stroke through anti-inflammation. However, the direct effect of HSYA on microglia following ischemia is unknown. This study confirmed whether HSYA could suppress inflammatory responses of BV2 microglia after oxygen glucose deprivation (OGD). BV2 microglia viability after OGD with or without HSYA was measured by MTT assay, PI/Annexin staining and LDH assay. Pro-inflammatory cytokines including 1L-1β, TNF-α, iNOS, COX-2, MCP-1 were determined by RT-PCR and western blotting. Activity of NF-κB and MAPK pathway were detected by western blotting. The results demonstrated that HSYA improved the viability of BV2 cells 12h after OGD with the profound dosage at 100mg/L by MTT assay. This observation was also confirmed by PI/Annexin staining and LDH assay. HSYA decreased the mRNA level of 1L-1β, TNF-α, iNOS, COX-2, MCP-1 and protein level of iNOS, COX-2 in BV2 microglia 12h after OGD. OGD enhanced the phosphorylation of p38 and nuclear translocation of p65 in BV2 microglia, which was partially reserved by HSYA. Our results suggested that HSYA suppressed inflammatory responses in BV2 microglia induced by OGD, which is probably associated with the inhibition of the NF-κB signaling pathway and phosphorylation of p38.

Li J ，Zhang S ，Lu M ，Chen Z ，Chen C ，Han L ，Zhang M ，Xu Y ... -  《-》

Amyloid-beta causes memory impairment by disturbing the JAK2/STAT3 axis in hippocampal neurons.

Chiba T ，Yamada M ，Sasabe J ，Terashita K ，Shimoda M ，Matsuoka M ，Aiso S ... -  《-》

Hydroxysafflor Yellow A Inhibits Aβ(1-42)-Induced Neuroinflammation by Modulating the Phenotypic Transformation of Microglia via TREM2/TLR4/NF-κB Pathway in BV-2 Cells.

Hydroxysafflor yellow A (HSYA) is an extract from Carthamus tinctorius L. dry flowers (Compositae). HSYA has been shown to have neuroprotective effects on several Alzheimer's disease (AD) models. However, the exact mechanisms by which HSYA regulates neuroinflammation have still not been clarified. In this study, we investigated the mechanism by which HSYA regulates microglial activation and neuroinflammation via TREM2, and further clarified its underlying molecular mechanism. We silenced TREM2 in BV-2 cells and evaluated the expression of inflammatory markers (TNF-α, IL-1β, IL-4, IL-6, IL-10, and IL-13). The results showed that HSYA could up-regulate cell viability and improve the morphology of BV-2 cells injured by Aβ1-42. The results showed that Aβ1-42 could induce microglia to upregulate the expression of M1 markers (iNOS, IL-1β, IL-6) and downregulate M2 marker (Arg-1, IL-4, IL-10, IL-13) expression. HSYA reversed the effects of Aβ1-42 via TREM2, switching microglia from an M1 proinflammatory phenotype to an M2 anti-inflammatory phenotype. HSYA inhibited the Aβ1-42-induced activation of the TLR4/NF-κB transduction pathway by upregulating TREM2 and regulated the transcription of inflammatory cytokines via the downstream transcription factors NF-κB p65 and IκB-α. In conclusion, HSYA regulated the microglial inflammatory phenotype by regulating microglial (M1/M2) polarization in Aβ1-42-induced BV-2 cells which may be mediated by the TREM2/TLR4/NF-κB pathway.

Ren M ，Zhang M ，Zhang X ，Wang C ，Zheng Y ，Hu Y ... -  《-》