Irinotecan (CPT-11) Canonical Anti-Cancer Drug Can also Modulate Antiviral and Pro-Inflammatory Responses of Primary Human Synovial Fibroblasts

Alphaviruses are a group of arboviruses that generate chronic inflammatory rheumatisms in humans. Currently, no approved vaccines or antiviral therapies are available to prevent or treat alphavirus-induced diseases. The aim of this study was to evaluate the repositioning of the anti-cancer molecule irinotecan as a potential modulator of the antiviral and inflammatory responses of primary human synovial fibroblasts (HSF), the main stromal cells of the joint synovium. HSF were exposed to O’nyong-nyong virus (ONNV) and polyinosinic-polycytidylic acid (PIC) to mimic, respectively, acute and chronic infectious settings. The cytokine IL-1β was used as a major pro-inflammatory cytokine to stimulate HSF. Quantitative RT-PCR analysis revealed that irinotecan at 15 µM was able to amplify the antiviral response (i.e., interferon-stimulated gene expression) of HSF exposed to PIC and reduce the expression of pro-inflammatory genes (CXCL8, IL-6 and COX-2) upon IL-1β treatment. These results were associated with the regulation of the expression of several genes, including those encoding for STAT1, STAT2, p53 and NF-κB. Irinotecan did not modulate these responses in both untreated cells and cells stimulated with ONNV. This suggests that this drug could be therapeutically useful for the treatment of chronic and severe (rather than acute) arthritis due to viruses.

Berberine modulates hyper-inflammation in mouse macrophages stimulated with polyinosinic-polycytidylic acid via calcium-CHOP/STAT pathway

Berberine is a well-known quaternary ammonium salt that is usually found in the roots of such plants as Phellodendron amurense and Coptis chinensis. However, the effects of berberine on double-stranded RNA (dsRNA)-induced macrophages have not been fully reported. In this study, we examined the anti-inflammatory effects of berberine on dsRNA [polyinosinic-polycytidylic acid; poly I:C]-induced macrophages. Levels of nitric oxide (NO), Prostaglandin E2 (PGE2), first apoptosis signal receptor (Fas; CD95), cytokines, intracellular calcium, phosphorylated I-kappa-B-alpha (IkB-α), phosphorylated p38 mitogen-activated protein kinase (MAPK), phosphorylated ERK1/2, phosphorylated signal transducer and activated transcription 3 (STAT3), and mRNA expression of inflammatory genes in poly I:C-induced RAW 264.7 mouse macrophages were evaluated. Berberine significantly inhibited the production of NO, PGE2, Fas, GM-CSF, LIF, LIX, RANTES, and MIP-2 as well as calcium release in poly I:C-induced RAW 264.7 cells at concentrations of up to 50 μM. Berberine also significantly inhibited the phosphorylation of p38 MAPK, ERK1/2, IkB-α, and STAT3 in poly I:C-induced RAW 264.7 cells. Additionally, berberine significantly decreased the mRNA expressions of Chop (GADD153), Stat1, Stat3, and Fas in poly I:C-induced RAW 264.7 cells. Taken together, berberine has anti-inflammatory properties related to its inhibition of NO, PGE2, Fas, GM-CSF, LIF, LIX, RANTES, and MIP-2 in dsRNA-induced macrophages via the endoplasmic reticulum stress-related calcium-CHOP/STAT pathway.

Polyinosinic: Polycytidylic Acid and Murine Cytomegalovirus Modulate Expression of Murine IL-10 and IL-21 in White Adipose Tissue

White adipose tissue (WAT) produces interleukin-10 and other immune suppressors in response to pathogen-associated molecular patterns (PAMPs). It also homes a subset of B-cells specialized in the production of IL-10, referred to as regulatory B-cells. We investigated whether viral stimuli, polyinosinic: polycytidylic acid (poly(I:C)) or whole replicative murine cytomegalovirus (MCMV), could stimulate the expression of IL-10 in murine WAT using in vivo and ex vivo approaches. Our results showed that in vivo responses to systemic administration of poly(I:C) resulted in high levels of endogenously-produced IL-10 and IL-21 in WAT. In ex vivo WAT explants, a subset of B-cells increased their endogenous IL-10 expression in response to poly(I:C). Finally, MCMV replication in WAT explants resulted in decreased IL-10 levels, opposite to the effect seen with poly(I:C). Moreover, downregulation of IL-10 correlated with relatively lower number of Bregs. To our knowledge, this is the first report of IL-10 expression by WAT and WAT-associated B-cells in response to viral stimuli.