NOTCH and NF-kappa B interplay in chronic lymphocytic leukemia is independent of genetic lesion
INTERNATIONAL JOURNAL OF HEMATOLOGY
Authors: Baldoni, Stefano; Sportoletti, Paolo; Del Papa, Beatrice; Aureli, Patrizia; Dorillo, Erica; Rosati, Emanuela; Ciurnelli, Raffaella; Marconi, Pierfrancesco; Falzetti, Franca; Di Ianni, Mauro
Abstract
The NOTCH and nuclear factor kappa B (NF-kappa B) pathways are both constitutively activated in Chronic Lymphocytic Leukemia (CLL). We first described the NOTCH1 PEST domain mutation in a CLL subgroup, but the activation of the NOTCH pathway in NOTCH1-unmutated cases remains unexplained. Here, we investigated whether genetic lesions in the NF-kappa B/NOTCH loop might support the NOTCH activation status by sequencing negative (TNFAIP3/A20) and positive (TRAF2, TRAF5, TNFRSF11A/RANK, MAP3K7/TAK1, and CARD11) regulators of NF-kappa B together with NF-kappa B targets on the NOTCH pathway, the NOTCH ligands Jagged1 and Jagged2, in CLL patients. The sequence analysis revealed four missense mutations for A20, TRAF2, TRAF5 and RANK1 genes, all causing a change in amino acid group from polar to non-polar, but functional domains were not involved. Specific predictive software analyses confirmed that the amino acid changes have a low-functional impact on the protein. Our results show that in CLL, NF-kappa B regulators and Jagged are both unmutated, suggesting that the Jagged-mediated interplay between NF-kappa B and NOTCH is independent of genetic lesions.
Epigenetic regulation of inflammation in localized aggressive periodontitis
CLINICAL EPIGENETICS
Authors: Shaddox, L. M.; Mullersman, A. F.; Huang, H.; Wallet, S. M.; Langaee, T.; Aukhil, I.
Abstract
Background: We have previously demonstrated a Toll-like receptor (TLR)-mediated hyper-responsive phenotype in our cohort of localized aggressive periodontitis (LAP) individuals. However, mechanisms related to this phenotype are still not clear in the literature. The objective of this cross-sectional study is to examine the role of epigenetic regulation, specifically DNA methylation status of genes in the TLR pathway in this cohort. Peripheral blood was collected from 20 LAP patients and 20 healthy unrelated controls. Whole blood was stimulated with 1 mu l (100 ng/mu l) of purified Escherichia coli lipopolysaccharide (LPS) for 24 h and cyto/chemokines in the supernatants analyzed by Luminex multiplex assays. Genomic DNA extracted from buffy coats prepared from a second tube of whole blood was used for DNA methylation analysis by pyrosequencing of seven TLR signaling genes (FADD, MAP3K7, MYD88, IL6R, PPARA, IRAK1BP1, RIPK2). Results: Significant differences in the methylation status were observed at specific CpG positions in LAP patients compared to healthy controls and interestingly also between severe and moderate LAP. Specifically, subjects with moderate LAP presented hypermethylation of both the upregulating (MAP3K7, MYD88, IL6R, and RIPK2) and downregulating (FADD, IRAK, and PPARA) genes, while severe LAP presented hypomethylation of these genes. Further analysis on CpG sites with significant differences in methylation status correlates with an increased pro-inflammatory cytokine profile for LAP patients. Conclusions: Our findings suggest that epigenetic modifications of genes in the TLR pathway may orchestrate the thresholds for balancing induction and prevention of tissue destruction during the course of disease, and thus differ significantly at different stages of the disease, where moderate LAP shows hypermethylation and severe LAP shows hypomethylation of several genes.