A comparison of Chikungunya virus infection, progression, and cytokine profiles in human PMA-differentiated U937 and murine RAW264.7 monocyte derived macrophages

Abstract

Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that causes rash, fever and severe polyarthritis that can last for years in humans. Murine models display inflammation and macrophage infiltration only in the adjacent tissues at the site of inoculation, showing no signs of systemic polyarthritis. Monocyte-derived macrophages are one cell type suspected to contribute to a systemic CHIKV infection. The purpose of this study was to analyze differences in CHIKV infection in two different cell lines, human U937 and murine RAW264.7 monocyte derived macrophages. PMA-differentiated U937 and RAW264.7 macrophages were infected with CHIKV, and infectious virus production was measured by plaque assay and by reverse transcriptase quantitative PCR at various time points. Secreted cytokines in the supernatants were measured using cytometric bead arrays. Cytokine mRNA levels were also measured to supplement expression data. Here we show that CHIKV replicates more efficiently in human macrophages compared to murine macrophages. In addition, infected human macrophages produced around 10-fold higher levels of infectious virus when compared to murine macrophages. Cytokine induction by CHIKV infection differed between human and murine macrophages; IL-1, IL-6, IFN-γ, and TNF were significantly upregulated in human macrophages. This evidence suggests that CHIKV replicates more efficiently and induces a much greater pro-inflammatory cytokine profile in human macrophages, when compared to murine macrophages. This may shed light on the critical role that macrophages play in the CHIKV inflammatory response.

MBZM-N-IBT, a Novel Small Molecule, Restricts Chikungunya Virus Infection by Targeting nsP2 Protease Activity In Vitro , In Vivo , and Ex Vivo

“…Since MBZM-N-IBT showed the ability to modulate diverse proinflammatory mediators, further validation was carried out in vivo . Most of the murine models of CHIKV display inflammation and macrophage infiltration only in the adjacent tissues at the site of inoculation, and no signs of systemic polyarthritis were observed ( 48 ), whereas in the current study the model showed CHIKV-induced arthritis-like symptoms, which are comparable to CHIKV disease pathogenesis in human. The molecule was able to demonstrate good effect to modulate this symptoms.…”

Replication and innate immune responses of two chikungunya virus genotypes in human monocyte-derived macrophages

“…In addition to the 14 immune mediators of interest identified by the proteome profiler array, another five (CXCL-9, IL-12, PTX-3, IFN-α and IFN-β), which are known to be part of the immune response against CHIKV [20, 21], were selected for further testing with Luminex and ELISA (CXCL-10) assays, for samples from all eight donors.…”

“…In addition to the 14 immune mediators of interest identified by the proteome profiler array, another five (CXCL-9, IL-12, PTX-3, IFN-α and IFN-β), which are known to be part of the immune response against CHIKV [20,21], were selected for further testing with Luminex and ELISA (CXCL-10) assays, for samples from all eight donors. Expression of 11 immune mediators was detected in infected MDMs: chemokines CCL-2, CCL-3, CCL-4, RANTES, CXCL-9 and CXCL-10, cytokines IL-1Ra, IL-8, MIF and IFN-α, and the cytokine-induced protein PTX3 (summarized in Figs 4 and S5).…”

TLR4 is one of the receptors for Chikungunya virus envelope protein E2 and regulates virus induced pro-inflammatory responses in host macrophages

“…In addition to the mice model, earlier reports are also available on the CHIKV-driven pro-inflammatory cytokine burst and associated symptoms in human patient studies, in vivo ( 20 , 21 ). Accordingly, the effect of TLR4 inhibition could be further explored in experimental in vitro or in vivo setups with CHIKV-infected patient samples.…”