A Study on Gene Expression Profile of Endogenous Antioxidant Enzymes: CAT, MnSOD and GPx in Dengue Patients

Abstract

Dengue is an arthropod-borne threat among tropical countries. Currently no effective means to treat the virus or to predict which patient will develop the severe form of the disease. Recently the relationship between oxidative/antioxidative response and dengue pathogenesis was suggested. Based on this the present study has analysed the expression of endogenous antioxidant genes: Catalase (CAT), Superoxide dismutase (MnSOD) and Glutathione peroxidase in patients with dengue compared to other febrile illness (OFI) and healthy controls. The study enrolled 88 dengue confirmed patients comprising 56 were patients with non-severe dengue, and 32 were severe dengue cases, 31 were patients with OFI, and 63 healthy controls were also involved. Peripheral blood mononuclear cells isolated from patients and controls during the day of admission and from the available cases on the day of defervescence were used to estimate the transcript levels by quantitative PCR. The expression levels of all the three genes were found to be down-regulated throughout the course of dengue infection ( < 0.05) and OFI cases compared to healthy controls. Within dengue group, no significant difference was observed in any of the parameters between severe and non-severe cases. Interestingly, a significant down-regulation of MnSOD expression was recorded in secondary dengue infection compared to primary during admission ( < 0.05). It was found that all the down-regulated study genes have positively correlated in all dengue cases during the day of admission ( < 0.01). But during defervescence, the same was found only between CAT and MnSOD. Down-regulated endogenous antioxidant enzymes during dengue infection could be the possible rationale of oxidative stress reported in dengue disease earlier. The present study markers could not distinguish dengue from OFI cases and severe from non-severe dengue cases. Mechanism of down-regulation has to be explored further which will pave the way for the therapeutic target in dengue disease.

Endogenous gene selection for relative quantification PCR and IL6 transcript levels in the PBMC’s of severe and non-severe dengue cases

“…PBMCs were separated from whole blood obtained from Healthy controls, OFI and dengue cases using HiSep LSM 1077 (Himedia, Mumbai, India), washed with PBS twice and stored in 1 mL RNAiso Plus reagent (Takara Bio Inc., Shiga, Japan) and kept at − 80° as described in our earlier studies [ 10 ]. Total RNA was extracted using RNA easy minikit (Qiagen, GmbH, Hilden, Germany) based on the manufacturer’s protocol.…”

“…The primers of the endogenous reference genes and target gene were used based on previous studies [ 9 , 10 , 17 , 20 ] and are described in Additional file 1 : Table S1. All reactions were performed in duplicates with a standard run protocol of initial denaturation at 95° for 30 s followed by 40 cycles of denaturation (95° for 5 s) and a combined annealing and extension (60° for 30 s).…”

Oxidative Stress Biomarkers as Prognostic Indicators of Severity in Patients With Dengue

“…Recently, Cherupanakkal, et al (Cherupanakkal et al, 2017), reported that MnSOD gene expression was not associated with severity of dengue disease in children and adults. In addition to the above, we have not found statistically significant differences in MnSOD activity between patients with severe dengue and those with dengue with warning signs, in both adults and children.…”

“…In addition to the explanations reported by Cherupanakkal, et al (Cherupanakkal et al, 2017), it is necessary to consider the presence of IgM autoantibodies against MnSOD, which could inhibit the protective effects of MnSOD. These antibodies have been reported in patients with acute viral infections (Ritter et al, 1994;Semrau et al, 1998), and it has been shown that may contribute to the oxidative damage of endothelial cells (Dalpke et al, 2003).…”

Life as a Vector of Dengue Virus: The Antioxidant Strategy of Mosquito Cells to Survive Viral Infection

“…In particular, expression levels of endogenous antioxidant genes including catalase (CAT), manganese superoxide dismutase (MnSOD), and glutathione peroxidase (GPX) were found to be downregulated in dengue patients. Of these, significant downregulation of MnSOD expression was recorded in patients with secondary dengue infection [ 126 ]. More results from dengue patients also showed significantly lower levels of the plasma Trolox-equivalent antioxidant capacity, serum paraoxonase, and erythrocyte-reduced glutathione (GSH) and glutathione peroxidase (GPx) activities [ 127 ].…”