Diabetes Inhibits Gr-1+ Myeloid Cell Maturation via Cebpa Deregulation.

Recruitment of innate immune cells from the bone marrow (BM) to an injury site is required for effective repair. In diabetes, this process is altered, leading to excessive recruitment and retention of dysfunctional myeloid cells that fail to promote angiogenesis, prolong inflammation, and block healing. The aberrant myeloid phenotype is partially mediated by stable intrinsic changes to developing cells in the BM that are induced by the diabetic (db) environment, but the exact mechanisms remain largely unknown. Here, we show that the db-derived Gr-1(+)CD11b(+) immature myeloid population has widespread misexpression of chromatin-remodeling enzymes and myeloid differentiation factors. Crucially, diabetes represses transcription of the key myeloid transcription factor CEBPA via diminished H3 Lys 27 promoter acetylation, leading to a failure in monocyte and granulocyte maturation. Restoring Cebpa expression by granulocyte colony-stimulating factor reverses the db phenotype and rescues myeloid maturation. Importantly, our data demonstrate a possible link between myeloid cell maturation and chronic inflammation.

Analysis of the UHRF1 expression in serum and tissue for gastric cancer detection.

OBJECTIVE: To analyze the Ubiquitin-like with PHD and ring finger domains (UHRF) 1 expression in gastric cancer (GC). METHODS: The concentrations of UHRF1 DNA in serum were compared between 187 GC patients and 56 healthy controls using real-time PCR. Immunohistochemical analysis using tissue microarrays was performed. RESULTS: UHRF1 DNA levels were significantly higher in GC patients compared to healthy controls (p < 0.001) and have associations with age and lymph node metastasis (LNM). The UHRF1 expression was significantly higher in tumor tissue than matched normal tissues (p < 0.001). CONCLUSIONS: The UHRF1 expression in serum and tissue may represent a novel biomarker for GC diagnosis and prognosis.

Heterogeneity within AML with CEBPA mutations; only CEBPA double mutations, but not single CEBPA mutations are associated with favourable prognosis.

CCAAT/enhancer binding protein alpha (CEBPA) mutations in AML are associated with favourable prognosis and are divided into N- and C-terminal mutations. The majority of AML patients have both types of mutations. We assessed the prognostic significance of single (n=7) and double (n=12) CEBPA mutations among 224 AML patients. Double CEBPA mutations conferred a decisively favourable overall (P=0.006) and disease-free survival (P=0.013). However, clinical outcome of patients with single CEBPA mutations was not different from CEBPA wild-type patients. In a multivariable analysis, only double -- but not single -- CEBPA mutations were identified as independent prognostic factors. These findings indicate heterogeneity within AML patients with CEBPA mutations.

Novel combinatorial interactions of GATA-1, PU.1, and C/EBPepsilon isoforms regulate transcription of the gene encoding eosinophil granule major basic protein.

GATA-1 and the ets factor PU.1 have been reported to functionally antagonize one another in the regulation of erythroid versus myeloid gene transcription and development. The CCAAT enhancer binding protein epsilon (C/EBPepsilon) is expressed as multiple isoforms and has been shown to be essential to myeloid (granulocyte) terminal differentiation. We have defined a novel synergistic, as opposed to antagonistic, combinatorial interaction between GATA-1 and PU.1, and a unique repressor role for certain C/EBPepsilon isoforms in the transcriptional regulation of a model eosinophil granulocyte gene, the major basic protein (MBP). The eosinophil-specific P2 promoter of the MBP gene contains GATA-1, C/EBP, and PU.1 consensus sites that bind these factors in nuclear extracts of the eosinophil myelocyte cell line, AML14.3D10. The promoter is transactivated by GATA-1 alone but is synergistically transactivated by low levels of PU.1 in the context of optimal levels of GATA-1. The C/EBPepsilon(27) isoform strongly represses GATA-1 activity and completely blocks GATA-1/PU.1 synergy. In vitro mutational analyses of the MBP-P2 promoter showed that both the GATA-1/PU.1 synergy, and repressor activity of C/EBPepsilon(27) are mediated via protein-protein interactions through the C/EBP and/or GATA-binding sites but not the PU.1 sites. Co-immunoprecipitations using lysates of AML14.3D10 eosinophils show that both C/EBPepsilon(32/30) and epsilon(27) physically interact in vivo with PU.1 and GATA-1, demonstrating functional interactions among these factors in eosinophil progenitors. Our findings identify novel combinatorial protein-protein interactions for GATA-1, PU.1, and C/EBPepsilon isoforms in eosinophil gene transcription that include GATA-1/PU.1 synergy and repressor activity for C/EBPepsilon(27).

Expression of receptor-Ck and SREBP genes in mononuclear cells from acute leukemia patients.

We have recently shown that Receptor-Ck regulated genes, involved in cellular growth and death through a transcriptional factor (SREBP) which has affinity for sterol regulatory element (SRE) present in the promoter region of these genes. The present study revealed that blasts, derived from both ALL and AML patients, were unable to express SREBP gene product although they had the capacity to express Receptor-Ck gene product. These results which depict defective Receptor-Ck-dependent signalling are in conformity with our previous results which showed that lymphocytes from CML patients as well as other human leukemic cell lines are unable to express gene coding for Receptor-Ck leading again to a state of impaired Receptor-Ck-dependent signalling. On the basis of these results, we propose that deregulated Receptor-Ck-dependent signalling may have an important role in leukemogenesis.