Does Dexamethasone Helps in Meningococcal Sepsis?

Chrysophanol Exerts Anti-inflammatory Activity by Targeting Histone Deacetylase 3 Through the High Mobility Group Protein 1-Nuclear Transcription Factor-Kappa B Signaling Pathway in vivo and in vitro

Chrysophanol (Chr) is the main monomer isolated from Rheum rhabarbarum. This study aimed to identify the potential in vitro and in vivo cytoprotective effects of Chr on lipopolysaccharide (LPS)-triggered acute lung injury (ALI). We used an ALI-murine model and constructed an inflammatory macrophage in vitro cell model to determine the cellular mechanisms involved in Chr-mediated activity. To observe the vital role of histone deacetylase 3 (HDAC3) in abolishing inflammation action, HDAC3 was downregulated using small interfering RNA. Analysis of the expression of nuclear transcription factor-kappa B p65 (NF-κB p65) and molecules of its downstream signaling pathway were assessed in vitro and in lung tissue samples using the mouse model. Concentrations of tumor necrosis factor-α, interleukin-1β, high mobility group protein 1 (HMGB1), and interleukin-16 in supernatants and the bronchoalveolar lavage fluid were measured using enzyme-linked immunosorbent assay. A reporter gene assay measured HMGB1 activity, and NF-κB p65 and HMGB1 intracellular localization was determined by immunofluorescence detection on histological lung samples from Chr-treated mice. The protein interactions between HMGB1, HDAC3, and NF-κB p65 were tested by co-immunoprecipitation. Chr treatment relieved LPS-induced lung lesions. Chr also enhanced superoxide dismutase levels in ALI mice. Chr reduced the LPS-induced protein expression of NF-κB and its related pathway molecules in both in vivo and in vitro models. Moreover, Chr downregulated LPS-enhanced HMGB1 expression, acetylation, and nuclear nucleocytoplasmic translocation. However, HDAC3 knockdown substantially reduced Chr-mediated HDAC3/NF-κB expression.

Furthermore, Chr enhanced HMGB1/HDAC3/NF-κB p65 complex interaction, whereas HDAC3 knockdown reduced Chr-mediated HMGB1/HDAC3/NF-κB p65 formation. This study showed that the protective effects induced by Chr were associated with the regulation of the HMGB1/NF-κB pathway via HDAC3.

Emodin Attenuates Lipopolysaccharide-Induced Acute Liver Injury via Inhibiting the TLR4 Signaling Pathway in vitro and in vivo

Aims: Emodin is an anthraquinone with potential anti-inflammatory properties. However, the possible molecular mechanisms and protective effects of emodin are not clear. The objective of this study was to investigate the possible molecular mechanisms and protective effects of emodin on lipopolysaccharide (LPS)-induced acute liver injury (ALI) via the Toll-like receptor 4 (TLR4) signaling pathway in the Raw264.7 cell line and in Balb/c mice. Methods: This study established an inflammatory cellular model and induced an ALI animal model. TLR4 was overexpressed by lentivirus and downregulated by small interfering RNA (siRNA) technology. The mRNA and protein levels of TLR4 and downstream molecules were detected in cells and liver tissue. The tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 levels in supernatant and serum were determined by ELISA. The distribution and expression of mannose receptor C type 1 (CD206) and arginase 1 (ARG1) in the liver were tested by immunofluorescence. Mouse liver function and histopathological observations were assessed. Results: Administration of emodin reduced the protein and/or mRNA levels of TLR4 and its downstream molecules following LPS challenge in Raw264.7 cells and in an animal model. Additionally, emodin suppressed the expression of TNF-α and IL-6 in cell culture supernatant and serum. The inhibitory effect of emodin was also confirmed in RAW264.7 cells, in which TLR4 was overexpressed or knocked down. Additionally, ARG1 and CD206 were elevated in the emodin groups. Emodin also decreased serum ALT and AST levels and alleviated the liver histopathological damage induced by LPS. Conclusion: Emodin showed excellent hepatoprotective effects against LPS-induced ALI, possibly by inhibiting TLR4 signaling pathways.