The HPSE Gene Insulator—A Novel Regulatory Element That Affects Heparanase Expression, Stem Cell Mobilization, and the Risk of Acute Graft versus Host Disease

Abstract

The HPSE gene encodes heparanase (HPSE), a key player in cancer, inflammation, and autoimmunity. We have previously identified a strong HPSE gene enhancer involved in self-regulation of heparanase by negative feedback exerted in a functional rs4693608 single-nucleotide polymorphism (SNP) dependent manner. In the present study, we analyzed the HPSE gene insulator region, located in intron 9 and containing rs4426765, rs28649799, and rs4364254 SNPs. Our results indicate that this region exhibits HPSE regulatory activity. SNP substitutions lead to modulation of a unique DNA-protein complex that affects insulator activity. Analysis of interactions between enhancer and insulator SNPs revealed that rs4693608 has a major effect on HPSE expression and the risk of post-transplantation acute graft versus host disease (GVHD). The C alleles of insulator SNPs rs4364254 and rs4426765 modify the activity of the HPSE enhancer, resulting in altered HPSE expression and increased risk of acute GVHD. Moreover, rs4426765 correlated with HPSE expression in activated mononuclear cells, as well as with CD3 levels and lymphocyte counts following G-CSF mobilization. rs4363084 and rs28649799 were found to be associated with CD34+ levels. Our study provides new insight into the mechanism of HPSE gene regulation and its impact on normal and pathological processes in the hematopoietic system.

CMV Seropositive Status Increases Heparanase SNPs Regulatory Activity, Risk of Acute GVHD and Yield of CD34+ Cell Mobilization

“…In previous studies, we identified two regulatory regions of the HPSE gene, a strong enhancer, located in intron 2 [ 20 ], and a 200 bp insulator mapped in intron 9 [ 21 ]. The number of functional SNPs in both regulatory regions and their interactions were characterized [ 21 ].…”

“…In previous studies, we identified two regulatory regions of the HPSE gene, a strong enhancer, located in intron 2 [ 20 ], and a 200 bp insulator mapped in intron 9 [ 21 ]. The number of functional SNPs in both regulatory regions and their interactions were characterized [ 21 ]. The enhancer rs4693608 SNP has a major impact on HPSE gene expression and the risk of acute graft-versus-host disease (GVHD) after hematopoietic stem cell transplantation (HSCT).…”

“…The enhancer rs4693608 SNP has a major impact on HPSE gene expression and the risk of acute graft-versus-host disease (GVHD) after hematopoietic stem cell transplantation (HSCT). The C alleles of insulator SNPs rs4364254 and rs4426765 modify the activity of the HPSE gene enhancer resulting in both altered heparanase expression and increased risk of developing acute GVHD [ 21 ]. In addition, the enhancer rs4363084 SNP and insulator rs28649799 SNP were shown to be associated with the yield of granulocyte-colony stimulating factor (G-CSF) mediated CD34 + cell mobilization in normal donors.…”

“…In addition, the enhancer rs4363084 SNP and insulator rs28649799 SNP were shown to be associated with the yield of granulocyte-colony stimulating factor (G-CSF) mediated CD34 + cell mobilization in normal donors. Moreover, rs4426765 correlates with HPSE gene expression in activated mononuclear cells (MNCs), and with CD3 cell number and lymphocyte counts in response to G-CSF-induced cell mobilization [ 21 ].…”

“…The present study analyzed the correlation between functional heparanase SNPs and CMV seropositivity. We assessed the involvement of the previously discovered enhancer and insulator SNPs [ 21 ] in the risk of acute GVHD and the yield of G-CSF mediated CD34 + mobilization in CMV seropositive versus seronegative individuals. Our results revealed a significant correlation between the C alleles of insulator rs4364254 and rs4426765 SNPs and susceptibility to CMV infection in healthy donors and patients with acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), and myelodysplastic syndrome (MDS).…”