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Identifier

000381979

Title

Study of TET2 gene in Chronic Idiopathic Neutropenia Patients

Alternative Title

Μελέτη του γονιδίου ΤΕΤ2 σε ασθενείς με Χρόνια Ιδιοπαθή Ουδετεροπενία

Author

Σημαντηράκης, Εμμανουήλ

Thesis advisor

Παπαδάκη Ελένη

Reviewer

Ποντίκογλου, Χαρίλαος
Καστρινάκη Χριστίνα

Abstract

Background: Mutations on Tet2 gene are common in MDS, AML and CMLL. Tet2 is an important enzyme that converts 5-methylcytosine into 5-hydroxymethylcytosine. 5-hydroxy-methylcytosine acts as a demethylation signal and Tet2 has emerged as an oncogene in the recent years. Inhibition of Tet2 gene leads to increased self-renewal of the HSC LSK compartment, promoting the differentiation of monocyte/granulocyte progenitors to monocytes in expense of the granulocytic development/differentiation. Aim: Based on our preliminary experiments on 7 patients, we found Tet2 SNP rs62621450 with increased frequency in Cretan CIN patients (7%) slightly more frequent, than that reported in the literature. Aim of this study is to investigate whether rs62621450 is a possible biomarker for CIN patients, by evaluating its existence in a larger group of patients, and by evaluating Tet2 mRNA levels in CIN and normal PBMCs and granulocytes in order to correlate the observed neutrophil depletion with a possible Tet2 gene downregulation. Methods: Identification of rs62621450: Peripheral blood granulocytes were isolated from 42 CIN patients and 30 normal subjects and DNA was isolated. The TaqMan Genotyping kit was used to identify the polymorphism. Evaluation of Tet2 mRNA levels: PBMCs and granulocytes were isolated from 16 patients and 16 normal subjects. Total RNA was isolated, reverse transcription performed and Tet2 mRNA levels were measured by the use of real-time PCR. The values were normalized versus GAPDH housekeeping gene and expression level were expressed as 2^-ΔCt values. Results: 1/42 CIN patients was heterozygous for rs62621450 (frequency 1.2%), while 3/30 healthy subjects were heterozygotes for the SNP (5%). Frequencies in our cohort study do not differ from the reported SNP frequency in literature (5%), as defined by Fisher’s exact Test (P= 0.3). Moreover, we found that Tet2 mRNA levels were significantly increased in patient PBMCs (P=0.0094), and in patient neutrophils (P=0.7), compared to controls. Summary/Conclusions: In our cohort study, Tet2 SNP rs6262145 does not correlate with CIN. Nevertheless a moderate but significant increase in Tet2 mRNA levels was observed in patient PBMCs compared to healthy subjects. This might result as a compensatory mechanism to neutrophil loss in patient blood, where secreted signaling may act upon progenitor cells to increase Tet2 expression, hence promoting their survival/differentiation towards granulocytes.

Language

English

Subject

Myelodysplastic syndromes

Neutropenia

Μυελοδυσπλασία

ΤΕΤ2

Χρόνια Ιδιοπαθής Ουδετεροπενία

Issue date

2012-12-11

Collection

School/Department--School of Medicine--Department of Medicine--Post-graduate theses