Comparison of Cytokine Expression Profile in Chikungunya and Dengue Co-Infected and Mono-Infected Patients' Samples

Increased Indoleamine 2,3-Dioxygenase 1 (IDO-1) Activity and Inflammatory Responses during Chikungunya Virus Infection

Chikungunya virus (CHIKV) infection causes intense cytokine/chemokine inflammatory responses and debilitating joint pain. Indoleamine2,3–dioxygenase 1 (IDO-1) is an enzyme that initiates the tryptophan degradation that is important in initial host innate immune defense against infectious pathogens. Besides that, IDO-1 activation acts as a regulatory mechanism to prevent overactive host immune responses. In this study, we evaluated IDO-1 activity and cytokine/chemokine patterns in CHIKV patients. Higher IDO-1 (Kyn/Trp ratio) activation was observed during the early acute phase of CHIKV infection and declined in the chronic phase. Importantly, increased concentrations of Tumor Necrosis Factor-α (TNF-α), Interleukin-6 (IL-6), Interferon γ (IFN-γ), C-C motif chemokine ligand 2/Monocyte Chemoattractant Protein-1 (CCL2/MCP-1) and C-X-C motif chemokine ligand 10/Interferon Protein-10 (CXCL10/IP-10) were found in the acute phase of infection, while C-C motif chemokine ligand 4/Macrophage Inflammatory Protein 1 β (CCL4/MIP-1β) was found at increased concentrations in the chronic phase. Likewise, CHIKV patients with arthritis had significantly higher concentrations of CCL4/MIP-1β compared to patients without arthritis. Taken together, these data demonstrated increased IDO-1 activity, possibly exerting both antiviral effects and regulating exacerbated inflammatory responses. CCL4/MIP-1β may have an important role in the persistent inflammation and arthritic symptoms following chikungunya infection.

Association of C-reactive protein polymorphisms with serum-CRP concentration and viral load among dengue-chikungunya mono/co-infected patients

India being endemic to Dengue (DENV) and chikungunya (CHIKV) infections faces high patient-mortality and morbidity with overlapping clinical features. C-reactive protein (CRP) acts as early defence system in response to these infections. This study investigated role of CRP single-nucleotide polymorphism (SNP) genotypes and protein levels towards DENV/CHIKV mono and co-infection among eastern Indian patients. 128 DENV-CHIKV co-infected, 206 DENV and 167 CHIKV mono-infected patients were subjected to genotyping of two CRP SNPs by PCR-RFLP along with 102 healthy individuals. CRP levels were determined by immunoturbidimetry. Statistical correlation of CRP genotypes with CRP concentration, DENV-CHIKV mono/co-infection and viral load was performed. Patients with rs3093059-CT and rs3091244-TT were more susceptible to DENV-CHIKV co-infection, whereas, rs3091244-CT might have imparted protection against CHIKV mono-infection. DENV-HVL was more prevalent within rs3093059-TT and rs3091244-CT co-infected patients, whereas, CHIKV-HVL among rs3091244-CC. Acute phase co-infected patients had significantly higher CRP level compared to mono-infections. Both mono and co-infected patients with aches/pain exhibited 2-3-fold higher CRP levels compared to those without. rs3093059-CT and rs3091244-CT co-infected patients had higher CRP concentration compared to rs3093059-TT and rs3091244-CC, respectively. Co-infected patients with WHO-defined warning signs had higher anti-dengue IgG/IgM ratio and serum CRP level compared to those without warning signs. Thus, patient's CRP genotype might play significant role in determining serum-CRP concentration, viral load and DENV-CHIKV mono/co-infection.

Computational analysis of human host binding partners of chikungunya and dengue viruses during coinfection

Mosquito-borne viral diseases like chikungunya and dengue infections can cause severe illness and have become major public health concerns. Chikungunya virus (CHIKV) and dengue virus (DENV) infections share similar primary clinical manifestations and are transmitted by the same vector. Thus, the probability of their coinfection gets increased with more severe clinical complications in the patients. The present study was undertaken to elucidate the common human interacting partners of CHIKV and DENV proteins during coinfection. The viral-host protein-protein interactome was constructed using Cytoscape. Subsequently, significant host interactors were identified during coinfection. The network analysis elucidated 57 human proteins interacting with both CHIKV and DENV, represented as hub-bottlenecks. The functional and biological analyses of the 40 hub-bottlenecks revealed that they are associated with phosphoinositide 3-kinases (PI3K)/AKT, p53 signaling pathways, regulation of cell cycle and apoptosis during coinfection. Moreover, the molecular docking analysis uncovered the tight and robust binding of selected hub-bottlenecks with CHIKV/DENV proteins. Additionally, 23 hub-bottlenecks were predicted as druggable candidates that could be targeted to eradicate the host-viral interactions. The elucidated common host binding partners during DENV and CHIKV coinfection as well as indicated approved drugs can support the therapeutics development.