Inhibition of IL-6 methylation by Saikosaponin C regulates neuroinflammation to alleviate depression.

PURPOSE: Saikosaponin C (SSc) increases the expression of synaptic proteins and has a unexplored role in the prevention of AD and other neurodegeneration in humans. Therefore, we hypothesized that SSc has the potential to relief of depressive symptoms. Here, our study assessed the role of SSc on depression-like behaviors caused by a chronic social defeat stress (CSDS) in mice and explored the underlying mechanisms. METHODS: Behavioral tests were conducted to verify the efficacy of SSC in treating depression-like behavior in mice. The levels of IL-6, TNF-α and IL-1ß in brain tissue and BV2 cells were determined by ELISA. The effect of SSc on dendritic spine density was determined by Golgi staining. The percentage of monocytes in peripheral blood was measured using flow cytometry. The levels of STAT3 and DNMT1 under the influence of SSc were assessed by immunofluorescence. Protein expression of DNMT1, DNMT3a, DNMT3b, p-STAT3 and STAT3 in brain and BV2 cells was studied by Western blot. OE-DNMT1 was induced in the experiment to verify the inhibitory effect of DNMT1 on IL-6 methylation in SSC. Luciferase was used to detect SSC specific fragments affecting IL-6 methylation. RESULT: SSC treatment significantly alleviated depressive-like behavior, inhibited the levels of inflammatory cytokines including IL-6, IL-1ß and TNF-α, increased dendritic spine density and promoted synaptic plasticity in mice. SSC downregulated IL-6, STAT3 and DNMT1 expression in vivo and in vitro. SSC also decreased the percentage of monocytes in peripheral blood and suppressed neuroinflammation in mice. Overexpression of DNMT1 by shRNA abolished the inhibitory effect of SSc on IL-6 methylation. CONCLUSION: This study showed that SSc reduced IL6 methylation by inhibiting DNMT1 protein, induced a decrease in IL6 expression, promoted synaptic plasticity, and attenuated CSDS-induced depression-like behavior.

Xiao-Yao-San protects against anti-tuberculosis drug-induced liver injury by regulating Grsf1 in the mitochondrial oxidative stress pathway.

Background: Xiao-Yao-San (XYS) is a traditional Chinese prescription that regulates gastrointestinal function, improves mental and psychological abnormalities, and enhances liver function. However, the underlying mechanism of XYS for relieving anti-tuberculosis (AT) drug-induced liver injury is not clear. Objective: The current study examined whether XYS alleviated the symptoms of AT drug-induced liver injury in mice via the mitochondrial oxidative stress pathway. Methods: BALB/c male mice were randomly divided into four groups of 12 animals, including a control group, a model group, a 0.32 g/kg XYS group, and a 0.64 g/kg XYS group. The effect of XYS on the degree of liver injury was observed using haematoxylin and eosin staining (HE) and oil red O staining of pathological sections, biochemical parameters, and reactive oxygen species (ROS) levels. The protein expression of mitochondrial synthesis-related proteins and ferroptosis-related proteins was examined using Western blotting. Results: XYS improved the pathological changes in liver tissue and reduced the level of oxidative stress in liver-injured mice. XYS increased the expression of mitochondrial synthesis-related proteins and reversed the expression of ferroptosis-related proteins. Knockdown of G-rich RNA sequence binding factor 1 (Grsf1) expression with Grsf1 shRNA blocked the protective effects of XYS in liver injury. Conclusion: Our findings suggest that XYS alleviates AT drug-induced liver injury by mediating Grsf1 in the mitochondrial oxidative stress pathway.

Chrysophanol, a main anthraquinone from Rheum palmatum L. (rhubarb), protects against renal fibrosis by suppressing NKD2/NF-κB pathway.

PURPOSE: Chronic kidney disease (CKD), characterized as renal dysfunction and multi-system damage, has become a serious public health problem with high prevalence and mortality. Rheum palmatum L. (rhubarb) is one of the most widely used Chinese herb with renal protective activity. However, the active components and underlying mechanisms of rhubarb remain unknown. In this work, we tried to explore the pharmacological mechanism of chrysophanol, a main anthraquinone from rhubarb, against CKD by in vivo and in vitro models. STUDY DESIGN: The therapeutic effect of chrysophanol and its underlying mechanism were investigated using CKD mouse model induced by unilateral ureteral occlusion (UUO), and human kidney 2 (HK-2) cells stimulated by TGF-ß1 in vivo. METHODS: The impact of chrysophanol on renal function, inflammation, fibrosis of CKD mice were evaluated. Then, the protein expressions of FN1, collagen ɑI, α-SMA, NF-κB and naked keratinocyte homolog 2 (NKD2) were investigated. In vitro studies, the inhibition on inflammation and fibrogenesis by chrysophanol was further validated in TGF-ß1-stimulated HK2 cells, and the regulation of chrysophanol on NKD2/NF-κB pathway was analyzed. Moreover, NKD2 was overexpressed in HK-2 cells to confirm the role of NKD2/NF-κB pathway in chrysophanol-mediated efficacy. Finally, the binding mode of chrysophanol with NKD2 was studied using in silico molecular docking and microscale thermophoresis (MST) assay. RESULTS: Chrysophanol could significantly improve the kidney dysfunction, alleviate renal pathology, and reverse the elevated levels of renal fibrosis markers such as FN1, collagen ɑI and α-SMA. Furthermore, chrysophanol effectively inhibited TNF-α, IL-6, and IL-1ß production, and suppressed NF-κB activation and NKD2 expression. The findings of in vitro study were consistent with those of animal expriment. Using NKD2-overexpressing HK-2 cells, we also demonstrated that overexpression of NKD2 significantly compromised the anti-fibrotic effects of chrysophanol. In addition, molecular docking and MST analysis revealed that NKD2 was a direct target of chrysophanol. CONCLUSION: Together, our work demonstrated for the first time that chrysophanol could effectively ameliorate renal fibrosis by inhibiting NKD2/NF-κB pathway. Chrysophanol can potentially prevent CKD by suppressing renal NKD2 expression directly.

Astragalin attenuates depression-like behaviors and memory deficits and promotes M2 microglia polarization by regulating IL-4R/JAK1/STAT6 signaling pathway in a murine model of perimenopausal depression.

RATIONALE: Neuroinflammation can be alleviated via M2 microglia polarization, which could promote the recovery of perimenopausal depression. Astragalin (AST) possesses anti-neuroinflammatory activity. However, the effects of AST on perimenopausal depression and the molecular mechanism in regulating microglia polarization remained unknown. OBJECTIVES: The purpose was to investigate the effects of AST on mice with simulated perimenopausal depression through regulating microglia polarization. It was aimed to clarify the molecular mechanism related to the interleukin-4 receptor (IL-4R)/janus kinase (JAK) 1/signal transducer and activator of transcription (STAT) 6 signaling pathway. METHODS: The ovariectomy (OVX)/chronic unpredictable mild stress (CUMS)-induced murine model of perimenopausal depression was established and treated with AST. Then the depression-like behaviors and cognitive ability of mice were examined. After that, we detected the markers of microglia polarization and its regulatory signals. In addition, lipopolysaccharides (LPS)/adenosine triphosphate (ATP)-induced inflammatory BV2 model were used to verify the potential molecular mechanism. RESULTS: AST alleviated perimenopausal depression-like behaviors and memory deficits. AST alleviated microglia activation and increased Ki67-positive cells in dentate gyrus (DG). The viability of BV2 decreased by LPS/ATP was raised by AST. Moreover, both in vivo and in vitro, AST switched microglia from M1 phenotype caused by OVX/CUMS or LPS/ATP to M2 phenotype. The IL-4R/JAK1/STAT6 signaling was restored, and the levels of inducible nitric oxide synthase (iNOS), nuclear NF-KappaB-p65 were reduced by AST. Importantly, AST showed prevention against the ubiquitination modification and degradation of STAT6. CONCLUSIONS: Our results revealed new insights into molecular mechanism associated with microglia polarization in the effect of AST on the mouse model of perimenopausal depression.