RESUMO
Recent observations of the deregulated expression of several dipeptidyl peptidase (DP) IV-like enzymes in human cancers have led to presumptions of their pathogenic role in cancer. To further explore this concept we have characterized the expression of all DPIV-like enzymes in chronic lymphocytic leukemia (CLL). We have demonstrated the constitutive expression of DPIV, DP8, DP9, DPII and PEP mRNA and DPIV, DP8 and DP9 protein in CLL. FAP mRNA was not detected in CLL or normal B-lymphocytes. This correlated with an absence of FAP protein on the cell surface. This study also shows that DP8 mRNA expression is significantly upregulated in CLL compared to normal tonsil B-lymphocytes (p < 0.05) which may suggest biological importance in this disease. DP expression could not be correlated with any molecular or clinical prognostic markers for CLL in this cohort including IgVH mutational status, CD38, ZAP-70 or CD49d expression (n = 58). However, the constitutive expression of the DPIV-like enzymes in CLL and their emergence as potent immune regulators makes them candidate therapeutic targets in this disease.
Assuntos
Biomarcadores Tumorais/metabolismo , Dipeptidil Peptidase 4/metabolismo , Leucemia Linfocítica Crônica de Células B/enzimologia , RNA Mensageiro/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Dipeptidases/genética , Dipeptidases/metabolismo , Dipeptidil Peptidase 4/genética , Dipeptidil Peptidases e Tripeptidil Peptidases/genética , Dipeptidil Peptidases e Tripeptidil Peptidases/metabolismo , Endopeptidases , Feminino , Gelatinases/genética , Gelatinases/metabolismo , Perfilação da Expressão Gênica , Genes de Cadeia Pesada de Imunoglobulina/genética , Humanos , Leucemia Linfocítica Crônica de Células B/genética , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Pessoa de Meia-Idade , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Mutação , Prognóstico , Serina Endopeptidases/genética , Serina Endopeptidases/metabolismo , Regulação para CimaRESUMO
BACKGROUND: We have previously demonstrated that inhibition of dipeptidyl peptidase (DP) activity partially attenuates dextran sulfate sodium (DSS) colitis in mice. The aim of this study was to further investigate the mechanisms of this protection. MATERIALS AND METHODS: Wildtype (WT) and DPIV(-/-) mice consumed 2% DSS in drinking water for 6 days to induce colitis. Mice were treated with saline or the DP inhibitors Ile-Pyrr-(2-CN)*TFA or Ile-Thia. DP mRNA and enzyme levels were measured in the colon. Glucagon-like peptide (GLP)-2 and GLP-1 concentrations were determined by radioimmunoassay, regulatory T-cells (Tregs) by fluorescence activated cell sorting (FACS) on FOXp3+T cells in blood, and neutrophil infiltration assessed by myeloperoxidase (MPO) assay. RESULTS: DP8 and DP2 mRNA levels were increased (P < 0.05) in WT+saline mice compared to untreated WT mice with colitis. Cytoplasmic DP enzyme activity was increased (P < 0.05) in DPIV(-/-) mice at day 6 of DSS, while DP2 activity was increased (P < 0.05) in WT mice with colitis. GLP-1 (63%) and GLP-2 (50%) concentrations increased in WT+Ile-Pyrr-(2-CN)*TFA mice compared to day-0 controls. MPO activity was lower in WT+Ile-Thia and WT+Ile-Pyrr-(2-CN)*TFA treated mice compared to WT+saline (P < 0.001) at day 6 colitis. CONCLUSIONS: DP expression and activity are differentially regulated during DSS colitis, suggesting a pathophysiological role for these enzymes in human inflammatory bowel disease (IBD). DP inhibitors impaired neutrophil recruitment and maintenance of the Treg population during DSS-colitis, providing further preclinical evidence for the potential therapeutic use of these inhibitors in IBD. Finally, DPIV appears to play a critical role in mediating the protective effect of DP inhibitors.
Assuntos
Colite/enzimologia , Colo/enzimologia , Dipeptidil Peptidases e Tripeptidil Peptidases/biossíntese , Animais , Colite/induzido quimicamente , Colo/química , Sulfato de Dextrana/farmacologia , Inibidores da Dipeptidil Peptidase IV/farmacologia , Dipeptidil Peptidases e Tripeptidil Peptidases/antagonistas & inibidores , Dipeptidil Peptidases e Tripeptidil Peptidases/genética , Modelos Animais de Doenças , Peptídeo 1 Semelhante ao Glucagon/análise , Peptídeo 2 Semelhante ao Glucagon/análise , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Infiltração de Neutrófilos , Peroxidase/análise , Linfócitos T Reguladores/efeitos dos fármacosRESUMO
Dipeptidyl peptidases (DP) 8 and 9 are members of the DPIV enzyme family. Other members include DPIV, fibroblast activation protein (FAP) and the non-enzymes DP6 and DP10. DPIV family members have diverse biological roles, and have been implicated in a range of diseases including diabetes, cancer, inflammatory bowel disease, multiple sclerosis (MS), arthritis and asthma. While DP8/9 biological functions are yet to be established, they have been predicted to have similar roles to the other DPs due to high sequence similarities within the active site of the enzymes. While there is mounting evidence towards the involvement of DP8 and/or DP9 in innate and acquired immunity, direct proof for the link between DP8 and DP9 and human disease is yet to be definitively shown, thus DP8 and 9 proteins remain guilty by association.