AA IDO1 Variant Genotype (G2431A, rs3739319) Is Associated with Severe Dengue Risk Development in a DEN-3 Brazilian Cohort
VIRAL IMMUNOLOGY
Authors: Azevedo, Beatriz Peixoto; Farias, Pablo Cantalice S.; Pastor, Andre Filipe; Medeiros Davi, Caio Cesar; Pereira da Costa Neco, Heytor Victor; de Lima, Raul Emidio; Acioli-Santos, Bartolomeu
Abstract
Dengue is considered one of the most challenging public health threats in the world. Infection may be clinically asymptomatic but can result in severe forms. The indoleamine 2,3 dioxygenase (IDO) gene encodes one of first enzymes (IDO) of the kynurenine pathway. This study aimed to verify the association between G2431A IDO1 gene single nucleotide polymorphism (SNP) (rs3739319) and dengue fever development. We included 299 dengue-infected individuals in the study and 96 dengue-free controls. We collected clinical and diagnostic test data and divided the patients with dengue infection into three groups, based on World Health Organization (WHO) criteria: 131 Dengue without warning signs (DWOS), 143 Dengue with warning signs (DWS), and 25 severe dengue (SD). We genotyped 193 of the dengue cases using quantitative polymerase chain reaction to the SNP rs3739319. The other 106 dengue cases and 96 dengue-free controls had previously been genotyped using the Illumina Genotyping Kit. Genotyping of the infected patients revealed frequencies of 106 GG (35.4%), 126 GA (42.1%), and 67 AA (22.4%), whereas the nondengue exposed control group showed similar frequencies, 29 GG (30.2%), 52 GA (54.2%), and 15 AA (15.6%). Under risk analysis we found that AA genotype patients had a higher risk of developing SD in a codominant model (AA x GG; odds ratio [OR] = 11.5-fold in comparison to non-SD group -DWOS and -DWS patients; confidence interval [CI] = 0.02-0.32; Yates correction = 1.9e-05) and in a recessive model (AA x AG+GG; OR = 9.41; CI = 3.62-26.7; Yates correction = 4.8e-08). An allelic model reinforced the association between A allele and SD phenotype development that was found in the SD versus DWOS+DWS analysis (OR = 3.59; CI = 1.50-9.56; Yates correction = 0.0033). Our data show an association between the IDO G2431A variant and the risk for SD. This SNP may be relevant for further investigation into disease mechanisms and host factors in future genetic and pathophysiological studies.
Activation of the Kynurenine Pathway in Human Malignancies Can Be Suppressed by the Cyclin-Dependent Kinase Inhibitor Dinaciclib
FRONTIERS IN IMMUNOLOGY
Authors: Riess, Christin; Schneider, Bjoern; Kehnscherper, Hanna; Gesche, Julia; Irmscher, Nina; Shokraie, Fatemeh; Classen, Carl Friedrich; Wirthgen, Elisa; Domanska, Grazyna; Zimpfer, Annette; Strueder, Daniel; Junghanss, Christian; Maletzki, Claudia
Abstract
Indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO2) are the key enzymes of tryptophan (TRP) metabolism in the kynurenine pathway (KP). Both enzymes function as indicators of immunosuppression and poor survival in cancer patients. Direct or indirect targeting of either of these substances seems thus reasonable to improve therapy options for patients. In this study, glioblastoma multiforme (GBM) as well as head and neck squamous cell carcinomas (HNSCC) were examined because of their different mechanisms of spontaneous and treatment-induced immune escape. Effects on gene expression and protein levels were examined. Accompanying assessment of TRP metabolites from treated GBM cell culture supernatants was conducted. Our results show a heterogeneous and inversely correlated expression profile of TRP-metabolizing genes among GBM and HNSCC cells, with low, but inducible IDO1 expression upon IFN gamma treatment. TDO2 expression was higher in GBM cells, while genes encoding kynurenine aminotransferases were mainly confined to HNSCC cells. These data indicate that the KP is active in both entities, with however different enzymes involved in TRP catabolism. Upon treatment with Temozolomide, the standard of care for GBM patients, IDO1 was upregulated. Comparable, although less pronounced effects were seen in HNSCC upon Cetuximab and conventional drugs (i.e., 5-fluorouracil, Gemcitabine). Here, IDO1 and additional genes of the KP (KYAT1, KYAT2, and KMO) were induced. Vice versa, the novel yet experimental cyclin-dependent kinase inhibitor Dinaciclib suppressed KP in both entities. Our comprehensive data imply inhibition of the TRP catabolism by Dinaciclib, while conventional chemotherapeutics tend to activate this pathway. These data point to limitations of conventional therapy and highlight the potential of targeted therapies to interfere with the cells' metabolism more than anticipated.