McCaughan GW

References (26)

Title : DPP9: Comprehensive In Silico Analyses of Loss of Function Gene Variants and Associated Gene Expression Signatures in Human Hepatocellular Carcinoma - Huang_2021_Cancers.(Basel)_13_
Author(s) : Huang JC , Emran AA , Endaya JM , McCaughan GW , Gorrell MD , Zhang HE
Ref : Cancers (Basel) , 13 : , 2021
Abstract : Dipeptidyl peptidase (DPP) 9, DPP8, DPP4 and fibroblast activation protein (FAP) are the four enzymatically active members of the S9b protease family. Associations of DPP9 with human liver cancer, exonic single nucleotide polymorphisms (SNPs) in DPP9 and loss of function (LoF) variants have not been explored. Human genomic databases, including The Cancer Genome Atlas (TCGA), were interrogated to identify DPP9 LoF variants and associated cancers. Survival and gene signature analyses were performed on hepatocellular carcinoma (HCC) data. We found that DPP9 and DPP8 are intolerant to LoF variants. DPP9 exonic LoF variants were most often associated with uterine carcinoma and lung carcinoma. All four DPP4-like genes were overexpressed in liver tumors and their joint high expression was associated with poor survival in HCC. Increased DPP9 expression was associated with obesity in HCC patients. High expression of genes that positively correlated with overexpression of DPP4, DPP8, and DPP9 were associated with very poor survival in HCC. Enriched pathways analysis of these positively correlated genes featured Toll-like receptor and SUMOylation pathways. This comprehensive data mining suggests that DPP9 is important for survival and that the DPP4 protease family, particularly DPP9, is important in the pathogenesis of human HCC.
ESTHER : Huang_2021_Cancers.(Basel)_13_
PubMedSearch : Huang_2021_Cancers.(Basel)_13_
PubMedID: 33915844

Title : A Novel Purification Procedure for Active Recombinant Human DPP4 and the Inability of DPP4 to Bind SARS-CoV-2 - Xi_2020_Molecules_25_
Author(s) : Xi CR , Di Fazio A , Nadvi NA , Patel K , Xiang MSW , Zhang HE , Deshpande C , Low JKK , Wang XT , Chen Y , McMillan CLD , Isaacs A , Osborne B , Vieira de Ribeiro AJ , McCaughan GW , Mackay JP , Church WB , Gorrell MD
Ref : Molecules , 25 : , 2020
Abstract : Proteases catalyse irreversible posttranslational modifications that often alter a biological function of the substrate. The protease dipeptidyl peptidase 4 (DPP4) is a pharmacological target in type 2 diabetes therapy primarily because it inactivates glucagon-like protein-1. DPP4 also has roles in steatosis, insulin resistance, cancers and inflammatory and fibrotic diseases. In addition, DPP4 binds to the spike protein of the MERS virus, causing it to be the human cell surface receptor for that virus. DPP4 has been identified as a potential binding target of SARS-CoV-2 spike protein, so this question requires experimental investigation. Understanding protein structure and function requires reliable protocols for production and purification. We developed such strategies for baculovirus generated soluble recombinant human DPP4 (residues 29-766) produced in insect cells. Purification used differential ammonium sulphate precipitation, hydrophobic interaction chromatography, dye affinity chromatography in series with immobilised metal affinity chromatography, and ion-exchange chromatography. The binding affinities of DPP4 to the SARS-CoV-2 full-length spike protein and its receptor-binding domain (RBD) were measured using surface plasmon resonance and ELISA. This optimised DPP4 purification procedure yielded 1 to 1.8 mg of pure fully active soluble DPP4 protein per litre of insect cell culture with specific activity >30 U/mg, indicative of high purity. No specific binding between DPP4 and CoV-2 spike protein was detected by surface plasmon resonance or ELISA. In summary, a procedure for high purity high yield soluble human DPP4 was achieved and used to show that, unlike MERS, SARS-CoV-2 does not bind human DPP4.
ESTHER : Xi_2020_Molecules_25_
PubMedSearch : Xi_2020_Molecules_25_
PubMedID: 33218025

Title : Covid-19 and co-morbidities: a role for Dipeptidyl Peptidase 4 (DPP4) in disease severity? - Bassendine_2020_J.Diabetes__
Author(s) : Bassendine MF , Bridge SH , McCaughan GW , Gorrell MD
Ref : J Diabetes , : , 2020
Abstract : The Covid-19 pandemic is caused by a novel betacoronavirus, SARS-CoV-2, similar to SARS-CoV and MERS-CoV, which cause acute respiratory distress syndrome and case fatalities. Covid-19 disease severity is worse in older obese patients with comorbidities such as diabetes, hypertension, cardiovascular disease and chronic lung disease. Cell binding and entry of betacoronaviruses is via their surface spike glycoprotein; SARS-CoV binds to the metalloprotease angiotensin-converting enzyme 2, abbreviated hereafter to ACE2, MERS-CoV utilises dipeptidyl peptidase 4, abbreviated hereafter to DPP4, and recent modelling of the structure of SARS-CoV-2 spike glycoprotein predicts that it can interact with human DPP4 in addition to ACE2. DPP4 is a ubiquitous membrane-bound aminopeptidase that circulates in plasma; it is multifunctional with roles in nutrition, metabolism, immune and endocrine systems. DPP4 activity differentially regulates glucose homeostasis and inflammation via its enzymatic activity and non-enzymatic immunomodulatory effects. The importance of DPP4 for the medical community has been highlighted by the approval of DPP4 inhibitors, or gliptins, for the treatment of Type 2 diabetes mellitus. This review discusses the dysregulation of DPP4 in Covid-19 comorbid conditions; DPP4 activity is higher in older individuals and increased plasma DPP4 is a predictor of the onset of metabolic syndrome. DPP4 upregulation may be a determinant of Covid-19 disease severity, which creates interest regarding the use of gliptins in management of Covid-19. Also, knowledge of the chemistry and biology of DPP4 could be utilised to develop novel therapies to block viral entry of some betacoronaviruses, potentially including SARS-CoV-2. This article is protected by copyright. All rights reserved.
ESTHER : Bassendine_2020_J.Diabetes__
PubMedSearch : Bassendine_2020_J.Diabetes__
PubMedID: 32394639

Title : Immune regeneration in irradiated mice is not impaired by the absence of DPP9 enzymatic activity - Gall_2019_Sci.Rep_9_7292
Author(s) : Gall MG , Zhang HE , Lee Q , Jolly CJ , McCaughan GW , Cook A , Roediger B , Gorrell MD
Ref : Sci Rep , 9 :7292 , 2019
Abstract : The ubiquitous intracellular protease dipeptidyl peptidase 9 (DPP9) has roles in antigen presentation and B cell signaling. To investigate the importance of DPP9 in immune regeneration, primary and secondary chimeric mice were created in irradiated recipients using fetal liver cells and adult bone marrow cells, respectively, using wild-type (WT) and DPP9 gene-knockin (DPP9(S729A)) enzyme-inactive mice. Immune cell reconstitution was assessed at 6 and 16 weeks post-transplant. Primary chimeric mice successfully regenerated neutrophils, natural killer, T and B cells, irrespective of donor cell genotype. There were no significant differences in total myeloid cell or neutrophil numbers between DPP9-WT and DPP9(S729A)-reconstituted mice. In secondary chimeric mice, cells of DPP9(S729A)-origin cells displayed enhanced engraftment compared to WT. However, we observed no differences in myeloid or lymphoid lineage reconstitution between WT and DPP9(S729A) donors, indicating that hematopoietic stem cell (HSC) engraftment and self-renewal is not diminished by the absence of DPP9 enzymatic activity. This is the first report on transplantation of bone marrow cells that lack DPP9 enzymatic activity.
ESTHER : Gall_2019_Sci.Rep_9_7292
PubMedSearch : Gall_2019_Sci.Rep_9_7292
PubMedID: 31086209
Gene_locus related to this paper: human-DPP9

Title : The pro-fibrotic role of dipeptidyl peptidase 4 in carbon tetrachloride-induced experimental liver injury - Wang_2017_Immunol.Cell.Biol_95_443
Author(s) : Wang XM , Holz LE , Chowdhury S , Cordoba SP , Evans KA , Gall MG , Vieira de Ribeiro AJ , Zheng YZ , Levy MT , Yu DM , Yao TW , Polak N , Jolly CJ , Bertolino P , McCaughan GW , Gorrell MD
Ref : Immunol Cell Biol , 95 :443 , 2017
Abstract : Liver fibrosis is a progressive pathological process involving inflammation and extracellular matrix deposition. Dipeptidyl peptidase 4 (DPP4), also known as CD26, is a cell surface glycoprotein and serine protease. DPP4 binds to fibronectin, can inactivate specific chemokines, incretin hormone and neuropeptides, and influences cell adhesion and migration. Such properties suggest a pro-fibrotic role for this peptidase but this hypothesis needs in vivo examination. Experimental liver injury was induced with carbon tetrachloride (CCl4) in DPP4 gene knockout (gko) mice. DPP4 gko had less liver fibrosis and inflammation and fewer B cell clusters than wild type mice in the fibrosis model. DPP4 inhibitor-treated mice also developed less liver fibrosis. DNA microarray and PCR showed that many immunoglobulin (Ig) genes and some metabolism-associated transcripts were differentially expressed in the gko strain compared with wild type. CCl4-treated DPP4 gko livers had more IgM+ and IgG+ intrahepatic lymphocytes, and fewer CD4+, IgD+ and CD21+ intrahepatic lymphocytes. These data suggest that DPP4 is pro-fibrotic in CCl4-induced liver fibrosis and that the mechanisms of DPP4 pro-fibrotic action include energy metabolism, B cells, NK cells and CD4+ cells.
ESTHER : Wang_2017_Immunol.Cell.Biol_95_443
PubMedSearch : Wang_2017_Immunol.Cell.Biol_95_443
PubMedID: 27899813

Title : Neuropeptide Y is a physiological substrate of fibroblast activation protein: Enzyme kinetics in blood plasma and expression of Y2R and Y5R in human liver cirrhosis and hepatocellular carcinoma - Wong_2016_Peptides_75_80
Author(s) : Wong PF , Gall MG , Bachovchin WW , McCaughan GW , Keane FM , Gorrell MD
Ref : Peptides , 75 :80 , 2016
Abstract : Fibroblast activation protein (FAP) is a dipeptidyl peptidase (DPP) and endopeptidase that is weakly expressed in normal adult human tissues but is greatly up-regulated in activated mesenchymal cells of tumors and chronically injured tissue. The identities and locations of target substrates of FAP are poorly defined, in contrast to the related protease DPP4. This study is the first to characterize the physiological substrate repertoire of the DPP activity of endogenous FAP present in plasma. Four substrates, neuropeptide Y (NPY), peptide YY, B-type natriuretic peptide and substance P, were analyzed by mass spectrometry following proteolysis in human or mouse plasma, and by in vivo localization in human liver tissues with cirrhosis and hepatocellular carcinoma (HCC). NPY was the most efficiently cleaved substrate of both human and mouse FAP, whereas all four peptides were efficiently cleaved by endogenous DPP4, indicating that the in vivo degradomes of FAP and DPP4 differ. All detectable DPP-specific proteolysis and C-terminal processing of these neuropeptides was attributable to FAP and DPP4, and plasma kallikrein, respectively, highlighting their combined physiological significance in the regulation of these neuropeptides. In cirrhotic liver and HCC, NPY and its receptor Y2R, but not Y5R, were increased in hepatocytes near the parenchymal-stromal interface where there is an opportunity to interact with FAP expressed on nearby activated mesenchymal cells in the stroma. These novel findings provide insights into the substrate specificity of FAP, which differs greatly from DPP4, and reveal a potential function for FAP in neuropeptide regulation within liver and cancer biology.
ESTHER : Wong_2016_Peptides_75_80
PubMedSearch : Wong_2016_Peptides_75_80
PubMedID: 26621486

Title : Dipeptidyl peptidase 9 enzymatic activity influences the expression of neonatal metabolic genes - Chen_2016_Exp.Cell.Res_342_72
Author(s) : Chen Y , Gall MG , Zhang H , Keane FM , McCaughan GW , Yu DM , Gorrell MD
Ref : Experimental Cell Research , 342 :72 , 2016
Abstract : The success of dipeptidyl peptidase 4 (DPP4) inhibition as a type 2 diabetes therapy has encouraged deeper examination of the post-proline DPP enzymes. DPP9 has been implicated in immunoregulation, disease pathogenesis and metabolism. The DPP9 enzyme-inactive (Dpp9 gene knock-in; Dpp9 gki) mouse displays neonatal lethality, suggesting that DPP9 enzyme activity is essential in neonatal development. Here we present gene expression patterns in these Dpp9 gki neonatal mice. Taqman PCR arrays and sequential qPCR assays on neonatal liver and gut revealed differential expression of genes involved in cell growth, innate immunity and metabolic pathways including long-chain-fatty-acid uptake and esterification, long-chain fatty acyl-CoA binding, trafficking and transport into mitochondria, lipoprotein metabolism, adipokine transport and gluconeogenesis in the Dpp9 gki mice compared to wild type. In a liver cell line, Dpp9 knockdown increased AMP-activated protein kinase phosphorylation, which suggests a potential mechanism. DPP9 protein levels in liver cells were altered by treatment with EGF, HGF, insulin or palmitate, suggesting potential natural DPP9 regulators. These gene expression analyses of a mouse strain deficient in DPP9 enzyme activity show, for the first time, that DPP9 enzyme activity regulates metabolic pathways in neonatal liver and gut.
ESTHER : Chen_2016_Exp.Cell.Res_342_72
PubMedSearch : Chen_2016_Exp.Cell.Res_342_72
PubMedID: 26930324
Gene_locus related to this paper: mouse-dpp9

Title : Dipeptidyl peptidase 9 subcellular localization and a role in cell adhesion involving focal adhesion kinase and paxillin - Zhang_2015_Biochim.Biophys.Acta_1853_470
Author(s) : Zhang H , Chen Y , Wadham C , McCaughan GW , Keane FM , Gorrell MD
Ref : Biochimica & Biophysica Acta , 1853 :470 , 2015
Abstract : Dipeptidyl peptidase 9 (DPP9) is a ubiquitously expressed member of the DPP4 gene and protease family. Deciphering the biological functions of DPP9 and its roles in pathogenesis has implicated DPP9 in tumor biology, the immune response, apoptosis, intracellular epidermal growth factor-dependent signaling and cell adhesion and migration. We investigated the intracellular distribution of DPP9 chimeric fluorescent proteins and consequent functions of DPP9. We showed that while some DPP9 is associated with mitochondria, the strongest co-localization was with microtubules. Under steady state conditions, DPP9 was not seen at the plasma membrane, but upon stimulation with either phorbol 12-myristate 13-acetate or epidermal growth factor, some DPP9 re-distributed towards the ruffling membrane. DPP9 was seen at the leading edge of the migrating cell and co-localized with the focal adhesion proteins, integrin-beta1 and talin. DPP9 gene silencing and treatment with a DPP8/DPP9 specific inhibitor both reduced cell adhesion and migration. Expression of integrin-beta1 and talin was decreased in DPP9-deficient and DPP9-enzyme-inactive cells. There was a concomitant decrease in the phosphorylation of focal adhesion kinase and paxillin, indicating that DPP9 knockdown or enzyme inhibition suppressed the associated adhesion signaling pathway, causing impaired cell movement. These novel findings provide mechanistic insights into the regulatory role of DPP9 in cell movement, and may thus implicate DPP9 in tissue and tumor growth and metastasis.
ESTHER : Zhang_2015_Biochim.Biophys.Acta_1853_470
PubMedSearch : Zhang_2015_Biochim.Biophys.Acta_1853_470
PubMedID: 25486458

Title : A rare variant in human fibroblast activation protein associated with ER stress, loss of enzymatic function and loss of cell surface localisation - Osborne_2014_Biochim.Biophys.Acta_1844_1248
Author(s) : Osborne B , Yao TW , Wang XM , Chen Y , Kotan LD , Nadvi NA , Herdem M , McCaughan GW , Allen JD , Yu DM , Topaloglu AK , Gorrell MD
Ref : Biochimica & Biophysica Acta , 1844 :1248 , 2014
Abstract : Fibroblast activation protein (FAP) is a focus of interest as a potential cancer therapy target. This membrane bound protease possesses the unique catalytic activity of hydrolysis of the post-proline bond two or more residues from the N-terminus of substrates. FAP is highly expressed in activated fibroblastic cells in tumours, arthritis and fibrosis. A rare, novel, human polymorphism, C1088T, encoding Ser363 to Leu, occurring in the sixth blade of the beta propeller domain, was identified in a family. Both in primary human fibroblasts and in Ser363LeuFAP transfected cells, we showed that this single substitution ablates FAP dimerisation and causes loss of enzyme activity. Ser363LeuFAP was detectable only in endoplasmic reticulum (ER), in contrast to the distribution of wild-type FAP on the cell surface. The variant FAP showed decreased conformational antibody binding, consistent with an altered tertiary structure. Ser363LeuFAP expression was associated with upregulation of the ER chaperone BiP/GRP78, ER stress sensor ATF6, and the ER stress response target phospho-eIF2alpha, all indicators of ER stress. Proteasomal inhibition resulted in accumulation of Ser363LeuFAP, indicating the involvement of ER associated degradation (ERAD). Neither CHOP expression nor apoptosis was elevated, so ERAD is probably important for protecting Ser363LeuFAP expressing cells. These data on the first loss of function human FAP gene variant indicates that although the protein is vulnerable to an amino acid substitution in the beta-propeller domain, inactive, unfolded FAP can be tolerated by cells.
ESTHER : Osborne_2014_Biochim.Biophys.Acta_1844_1248
PubMedSearch : Osborne_2014_Biochim.Biophys.Acta_1844_1248
PubMedID: 24717288

Title : Quantitation of fibroblast activation protein (FAP)-specific protease activity in mouse, baboon and human fluids and organs - Keane_2013_FEBS.Open.Bio_4_43
Author(s) : Keane FM , Yao TW , Seelk S , Gall MG , Chowdhury S , Poplawski SE , Lai JH , Li Y , Wu W , Farrell P , Vieira de Ribeiro AJ , Osborne B , Yu DM , Seth D , Rahman K , Haber P , Topaloglu AK , Wang C , Thomson S , Hennessy A , Prins J , Twigg SM , McLennan SV , McCaughan GW , Bachovchin WW , Gorrell MD
Ref : FEBS Open Bio , 4 :43 , 2013
Abstract : The protease fibroblast activation protein (FAP) is a specific marker of activated mesenchymal cells in tumour stroma and fibrotic liver. A specific, reliable FAP enzyme assay has been lacking. FAP's unique and restricted cleavage of the post proline bond was exploited to generate a new specific substrate to quantify FAP enzyme activity. This sensitive assay detected no FAP activity in any tissue or fluid of FAP gene knockout mice, thus confirming assay specificity. Circulating FAP activity was approximately 20- and 1.3-fold less in baboon than in mouse and human plasma, respectively. Serum and plasma contained comparable FAP activity. In mice, the highest levels of FAP activity were in uterus, pancreas, submaxillary gland and skin, whereas the lowest levels were in brain, prostate, leukocytes and testis. Baboon organs high in FAP activity included skin, epididymis, bladder, colon, adipose tissue, nerve and tongue. FAP activity was greatly elevated in tumours and associated lymph nodes and in fungal-infected skin of unhealthy baboons. FAP activity was 14- to 18-fold greater in cirrhotic than in non-diseased human liver, and circulating FAP activity was almost doubled in alcoholic cirrhosis. Parallel DPP4 measurements concorded with the literature, except for the novel finding of high DPP4 activity in bile. The new FAP enzyme assay is the first to be thoroughly characterised and shows that FAP activity is measurable in most organs and at high levels in some. This new assay is a robust tool for specific quantitation of FAP enzyme activity in both preclinical and clinical samples, particularly liver fibrosis.
ESTHER : Keane_2013_FEBS.Open.Bio_4_43
PubMedSearch : Keane_2013_FEBS.Open.Bio_4_43
PubMedID: 24371721

Title : Regulation of dipeptidyl peptidase 8 and 9 expression in activated lymphocytes and injured liver - Chowdhury_2013_World.J.Gastroenterol_19_2883
Author(s) : Chowdhury S , Chen Y , Yao TW , Ajami K , Wang XM , Popov Y , Schuppan D , Bertolino P , McCaughan GW , Yu DM , Gorrell MD
Ref : World J Gastroenterol , 19 :2883 , 2013
Abstract : AIM: To investigate the expression of dipeptidyl peptidase (DPP) 8 and DPP9 in lymphocytes and various models of liver fibrosis.
METHODS: DPP8 and DPP9 expression were measured in mouse splenic CD4(+) T-cells, CD8(+) T-cells and B-cells (B220(+)), human lymphoma cell lines and mouse splenocytes stimulated with pokeweed mitogen (PWM) or lipopolysaccharide (LPS), and in dithiothreitol (DTT) and mitomycin-C treated Raji cells. DPP8 and DPP9 expression were measured in epidermal growth factor (EGF) treated Huh7 hepatoma cells, in fibrotic liver samples from mice treated with carbon tetrachloride (CCl4) and from multidrug resistance gene 2 (Mdr2/Abcb4) gene knockout (gko) mice with biliary fibrosis, and in human end stage primary biliary cirrhosis (PBC).
RESULTS: All three lymphocyte subsets expressed DPP8 and DPP9 mRNA. DPP8 and DPP9 expression were upregulated in both PWM and LPS stimulated mouse splenocytes and in both Jurkat T- and Raji B-cell lines. DPP8 and DPP9 were downregulated in DTT treated and upregulated in mitomycin-C treated Raji cells. DPP9-transfected Raji cells exhibited more annexin V(+) cells and associated apoptosis. DPP8 and DPP9 mRNA were upregulated in CCl4 induced fibrotic livers but not in the lymphocytes isolated from such livers, while DPP9 was upregulated in EGF stimulated Huh7 cells. In contrast, intrahepatic DPP8 and DPP9 mRNA expression levels were low in the Mdr2 gko mouse and in human PBC compared to non-diseased livers. CONCLUSION: These expression patterns point to biological roles for DPP8 and DPP9 in lymphocyte activation and apoptosis and in hepatocytes during liver disease pathogenesis.
ESTHER : Chowdhury_2013_World.J.Gastroenterol_19_2883
PubMedSearch : Chowdhury_2013_World.J.Gastroenterol_19_2883
PubMedID: 23704821

Title : A novel role of dipeptidyl peptidase 9 in epidermal growth factor signaling - Yao_2011_Mol.Cancer.Res_9_948
Author(s) : Yao TW , Kim WS , Yu DM , Sharbeen G , McCaughan GW , Choi KY , Xia P , Gorrell MD
Ref : Mol Cancer Research , 9 :948 , 2011
Abstract : Dipeptidyl peptidase IV (DPP4), DPP8, DPP9, and fibroblast activation protein (FAP), the four proteases of the DPP4 gene family, have unique peptidase and extra-enzymatic activities that have been implicated in various diseases including cancers. We report here a novel role of DPP9 in regulating cell survival and proliferation through modulating molecular signaling cascades. Akt (protein kinase B) activation was significantly inhibited by human DPP9 overexpression in human hepatoma cells (HepG2 and Huh7) and human embryonic kidney cells (HEK293T), whereas extracellular signal-regulated kinases (ERK1/2) activity was unaffected, revealing a pathway-specific effect. Interestingly, the inhibitory effect of DPP9 on Akt pathway activation was growth factor dependent. DPP9 overexpression caused apoptosis and significantly less epidermal growth factor (EGF)-mediated Akt activation in HepG2 cells. However, such inhibitory effect was not observed in cells stimulated with other growth factors, including connective tissue growth factor, hepatic growth factor, insulin or platelet-derived growth factor-BB. The effect of DPP9 on Akt did not occur when DPP9 enzyme activity was ablated by either mutagenesis or inhibition. The phosphatidylinositol 3-kinase (PI3K)/Akt pathway is a major downstream effector of Ras. We found that DPP9 and DPP8, but not DPP4 or FAP, associate with H-Ras, a key signal molecule of the EGF receptor signaling pathway. These findings suggest an important signaling role of DPP9 in the regulation of survival and proliferation pathways.
ESTHER : Yao_2011_Mol.Cancer.Res_9_948
PubMedSearch : Yao_2011_Mol.Cancer.Res_9_948
PubMedID: 21622624
Gene_locus related to this paper: human-DPP9

Title : The dipeptidyl peptidase IV family in cancer and cell biology - Yu_2010_FEBS.J_277_1126
Author(s) : Yu DM , Yao TW , Chowdhury S , Nadvi NA , Osborne B , Church WB , McCaughan GW , Gorrell MD
Ref : Febs J , 277 :1126 , 2010
Abstract : Of the 600+ known proteases identified to date in mammals, a significant percentage is involved or implicated in pathogenic and cancer processes. The dipeptidyl peptidase IV (DPIV) gene family, comprising four enzyme members [DPIV (EC 3.4.14.5), fibroblast activation protein, DP8 and DP9] and two nonenzyme members [DP6 (DPL1) and DP10 (DPL2)], are interesting in this regard because of their multiple diverse functions, varying patterns of distribution/localization and subtle, but significant, differences in structure/substrate recognition. In addition, their engagement in cell biological processes involves both enzymatic and nonenzymatic capabilities. This article examines, in detail, our current understanding of the biological involvement of this unique enzyme family and their overall potential as therapeutic targets.
ESTHER : Yu_2010_FEBS.J_277_1126
PubMedSearch : Yu_2010_FEBS.J_277_1126
PubMedID: 20074209

Title : The in vivo expression of dipeptidyl peptidases 8 and 9 - Yu_2009_J.Histochem.Cytochem_57_1025
Author(s) : Yu DM , Ajami K , Gall MG , Park J , Lee CS , Evans KA , McLaughlin EA , Pitman MR , Abbott CA , McCaughan GW , Gorrell MD
Ref : Journal of Histochemistry & Cytochemistry , 57 :1025 , 2009
Abstract : The dipeptidyl peptidase IV (DPIV) enzyme family contains both potential and proven therapeutic targets. Recent reports indicate the presence of DP8 and DP9 in peripheral blood lymphocytes, testis, lung, and brain. For a more comprehensive understanding of DP8 and DP9 tissue and cellular expression, mRNA and enzyme activity were examined. Many organs from C57BL/6 wild-type and DPIV gene-knockout mice were examined; DP8/9 enzyme activity was detected in the immune system, brain, testis, muscle, and epithelia. In situ hybridization localized DP8 and DP9 mRNA to lymphocytes and epithelial cells in liver, gastrointestinal tract, lymph node, spleen, and lung. DP8 and DP9 mRNA was detected in baboon and mouse testis, and DP9 expression was elevated in human testicular cancers. DP8 and DP9 mRNA were ubiquitous in day 17 mouse embryo, with greatest expression in epithelium (skin and gastrointestinal tract) and brain. Thus, DP8 and DP9 are widely expressed enzymes. Their expression in lymphocytes and epithelia indicates potential for roles in the digestive and immune systems. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.
ESTHER : Yu_2009_J.Histochem.Cytochem_57_1025
PubMedSearch : Yu_2009_J.Histochem.Cytochem_57_1025
PubMedID: 19581630
Gene_locus related to this paper: human-DPP8 , human-DPP9

Title : Fibroblast activation protein and chronic liver disease - Wang_2008_Front.Biosci_13_3168
Author(s) : Wang XM , Yao TW , Nadvi NA , Osborne B , McCaughan GW , Gorrell MD
Ref : Front Biosci , 13 :3168 , 2008
Abstract : Fibroblast activation protein (FAP) is the member of Dipeptidyl Peptidase IV (DPIV) gene family that is most similar to DPIV. Four members of this family, DPIV, FAP, DP8 and DP9 possess a rare catalytic activity, hydrolysis of a prolyl bond two residues from the substrate N terminus. Crystal structures show that the soluble form of FAP comprises two domains, an alpha/beta-hydrolase domain and an 8-blade beta-propeller domain. The interface between these two domains forms the catalytic pocket, and an opening for substrate access to the internal active site. The FAP homodimer is structurally very similar to DPIV but FAP glycoprotein expression is largely confined to mesenchymal cells in diseased and damaged tissue, notably the tissue remodelling region in chronically injured liver. FAP peptide substrates include denatured collagen and alpha2-antiplasmin. The functional roles of FAP in tumors and fibrotic tissue are not fully understood. This review places FAP in the context of chronic liver injury pathogenesis.
ESTHER : Wang_2008_Front.Biosci_13_3168
PubMedSearch : Wang_2008_Front.Biosci_13_3168
PubMedID: 17981786

Title : Structure and function in dipeptidyl peptidase IV and related proteins -
Author(s) : Gorrell MD , Wang XM , Park J , Ajami K , Yu DM , Knott H , Seth D , McCaughan GW
Ref : Advances in Experimental Medicine & Biology , 575 :45 , 2006
PubMedID: 16700507

Title : DP8 and DP9 have extra-enzymatic roles in cell adhesion, migration and apoptosis -
Author(s) : Yu DM , Wang XM , Ajami K , McCaughan GW , Gorrell MD
Ref : Advances in Experimental Medicine & Biology , 575 :63 , 2006
PubMedID: 16700509
Gene_locus related to this paper: human-DPP8 , human-DPP9

Title : Extraenzymatic functions of the dipeptidyl peptidase IV-related proteins DP8 and DP9 in cell adhesion, migration and apoptosis - Yu_2006_FEBS.J_273_2447
Author(s) : Yu DM , Wang XM , McCaughan GW , Gorrell MD
Ref : Febs J , 273 :2447 , 2006
Abstract : The dipeptidyl peptidase IV gene family contains the four peptidases dipeptidyl peptidase IV, fibroblast activation protein, dipeptidyl peptidase 8 and dipeptidyl peptidase 9. Dipeptidyl peptidase IV and fibroblast activation protein are involved in cell-extracellular matrix interactions and tissue remodeling. Fibroblast activation protein is upregulated and dipeptidyl peptidase IV is dysregulated in chronic liver disease. The effects of dipeptidyl peptidase 8 and dipeptidyl peptidase 9 on cell adhesion, cell migration, wound healing and apoptosis were measured by using green fluorescent protein fusion proteins to identify transfected cells. Dipeptidyl peptidase 9-overexpressing cells exhibited impaired cell adhesion, migration in transwells and monolayer wound healing on collagen I, fibronectin and Matrigel. Dipeptidyl peptidase 8-overexpressing cells exhibited impaired cell migration on collagen I and impaired wound healing on collagen I and fibronectin in comparison to the green fluorescent protein-transfected controls. Dipeptidyl peptidase 8 and dipeptidyl peptidase 9 enhanced induced apoptosis, and dipeptidyl peptidase 9 overexpression increased spontaneous apoptosis. Mechanistic investigations showed that neither the catalytic serine of dipeptidyl peptidase 8 or dipeptidyl peptidase 9 nor the Arg-Gly-Asp integrin-binding motif in dipeptidyl peptidase 9 were required for the impairment of cell survival, cell adhesion or wound healing. We have previously shown that the in vitro roles of dipeptidyl peptidase IV and fibroblast activation protein in cell-extracellular matrix interactions and apoptosis are similarly independent of catalytic activity. Dipeptidyl peptidase 9 overexpression reduced beta-catenin, tissue inhibitor of matrix metalloproteinases 2 and discoidin domain receptor 1 expression. This is the first demonstration that dipeptidyl peptidase 8 and dipeptidyl peptidase 9 influence cell-extracellular matrix interactions, and thus may regulate tissue remodeling.
ESTHER : Yu_2006_FEBS.J_273_2447
PubMedSearch : Yu_2006_FEBS.J_273_2447
PubMedID: 16704418
Gene_locus related to this paper: human-DPP8 , human-DPP9

Title : Molecular characterization of a novel dipeptidyl peptidase like 2-short form (DPL2-s) that is highly expressed in the brain and lacks dipeptidyl peptidase activity - Chen_2006_Biochim.Biophys.Acta_1764_33
Author(s) : Chen T , Ajami K , McCaughan GW , Gai WP , Gorrell MD , Abbott CA
Ref : Biochimica & Biophysica Acta , 1764 :33 , 2006
Abstract : DPL2 (DPP10) found at chromosome 2q14.1 is a member of the dipeptidyl peptidase IV (DPIV) gene family. Here we characterize a novel short DPL2 isoform (DPL2-s), a 789-amino acid protein, that differs from the previously described long DPL2 isoform (DPL2-l) at the N-terminal cytoplasmic domain by 13 amino acids. The two DPL2 isoforms use alternate first exons. DPL2 mRNA was expressed mainly in the brain and pancreas. Multiple forms of recombinant DPL2-s protein were observed in 293T cells, having mobilities 96 kDa, 100 kDa, and approximately 250 kDa which may represent soluble DPL2, transmembrane DPL2 and multimeric DPL2 respectively. DPL2 is glycosylated as a band shift is observed following PNGase F deglycosylation. DPL2-s was expressed primarily on the cell surface of transfected 293T and PC12 cells. DPL2-s exhibits high sequence homology with other DPIV peptidases, but lacks a catalytic serine residue and lacks dipeptidyl peptidase activity. Substitutions of Gly(644)-->Ser, Lys(643)Gly(644)-->TrpSer, or Asp(561)Lys(643)Gly(644)-->TyrTrpSer in the catalytic motif did not confer dipeptidyl peptidase activity upon DPL2-s. Thus, although DPL2 is similar in structure and sequence to the other dipeptidyl peptidases, it lacks vital residues required to confer dipeptidyl peptidase activity and has instead evolved features that enable it to act as an important component of voltage-gated potassium channels.
ESTHER : Chen_2006_Biochim.Biophys.Acta_1764_33
PubMedSearch : Chen_2006_Biochim.Biophys.Acta_1764_33
PubMedID: 16290253

Title : Development and resolution of experimental colitis in mice with targeted deletion of dipeptidyl peptidase IV - Geier_2005_J.Cell.Physiol_204_687
Author(s) : Geier MS , Tenikoff D , Yazbeck R , McCaughan GW , Abbott CA , Howarth GS
Ref : Journal of Cellular Physiology , 204 :687 , 2005
Abstract : Glucagon-like peptide-2 (GLP-2) is a potent intestinotrophic growth factor that enhances repair of damaged intestinal tissue. However, its bioactivity is limited by dipeptidyl peptidase IV (DPIV)-mediated degradation. We hypothesized that DPIV(-/-) mice would display an increased resistance to, and an enhanced recovery from, dextran sulfate sodium (DSS)-induced colitis compared to DPIV(+/+) mice. DPIV(+/+) and DPIV(-/-) mice consumed 2% DSS for 6 days, followed by a 15 day recovery period. Mice were killed at days 0, 3, 6, 9, 14, and 21 (n = 6-8) and the small intestine and colon removed for histological assessment of villus height, crypt depth, and crypt area. The epithelial cell proliferative labeling index was determined by proliferating cell nuclear antigen (PCNA) immunostaining. Small intestine, colon, and total body weight did not differ between DPIV(+/+) and DPIV(-/-) mice. Distal colon crypt depth did not differ significantly between DPIV(+/+) and DPIV(-/-) mice during the development of DSS-colitis or during the recovery phase. Similarly no significant effects were apparent on distal colon crypt area or PCNA labeling index between DPIV(+/+) and DPIV(-/-) during the development of and recovery from DSS-colitis. However, DPIV(-/-) mice still possessed significant levels of plasma DPIV-like activity. We conclude that loss of DPIV activity does not increase resistance to experimental colitis and hypothesize that other DPIV family members may also be involved in the cleavage of GLP-2.
ESTHER : Geier_2005_J.Cell.Physiol_204_687
PubMedSearch : Geier_2005_J.Cell.Physiol_204_687
PubMedID: 15754331

Title : Dipeptidyl peptidase 9 has two forms, a broad tissue distribution, cytoplasmic localization and DPIV-like peptidase activity - Ajami_2004_Biochim.Biophys.Acta_1679_18
Author(s) : Ajami K , Abbott CA , McCaughan GW , Gorrell MD
Ref : Biochimica & Biophysica Acta , 1679 :18 , 2004
Abstract : Dipeptidyl peptidase (DP) IV has a distinct substrate specificity in hydrolyzing a post-proline bond. Here we present novel data on the sizes and tissue distribution of human and rat gene products and the peptidase activity of the DPIV-related gene DP9. A short cDNA of 2589 bp and a long cDNA of 3006 bp of DP9 were cloned. A ubiquitous predominant DP9 mRNA transcript at 4.4 kb represented the short form, whereas a less abundant 5.0-kb transcript present predominantly in muscle represented the long form. Both forms of DP9 have no transmembrane domain and two potential N-linked glycosylation sites. DP9 exhibited post-proline dipeptidyl aminopeptidase activity and was a cytoplasmic, 110-kDa monomer. Thus, the six DPIV gene family members have diverse characteristics: only DP9 and DP8 have exclusively cytoplasmic localization and only DP9, DP8, fibroblast activation protein (FAP) and DPIV have peptidase activity.
ESTHER : Ajami_2004_Biochim.Biophys.Acta_1679_18
PubMedSearch : Ajami_2004_Biochim.Biophys.Acta_1679_18
PubMedID: 15245913

Title : Structural requirements for catalysis, expression, and dimerization in the CD26\/DPIV gene family - Ajami_2003_Biochemistry_42_694
Author(s) : Ajami K , Abbott CA , Obradovic M , Gysbers V , Kahne T , McCaughan GW , Gorrell MD
Ref : Biochemistry , 42 :694 , 2003
Abstract : Dipeptidyl peptidase IV (DP-IV/CD26), fibroblast activation protein (FAP), DP-like 1 (DPL1), DP8, DP9, and DPL2 comprise the CD26 gene family. CD26/DP-IV has roles in liver disease, T cell costimulation, chemokine biology, type II diabetes, and tumor biology. DPIV substrates include the glucagonlike peptides, neuropeptide Y, and the chemokines CCL3, CCL5, CCL11, CCL22, and CXCL12. We have proposed that the extracellular region of CD26 is analogous to prolyl oligopeptidase in consisting of an alpha/beta hydrolase domain contributed by both N- and C-terminal portions of the polypeptide and a seven-blade beta-propeller domain. Replacing the C-terminal portion of the predicted alpha/beta hydrolase domain of CD26 (residues 501-766) with the homologous portion of DP8 or DP9 produced intact proteins. However, these chimeric proteins lacked dimerization and peptidase activity, suggesting that CD26 dimerization requires the C-terminal portion of the alpha/beta hydrolase domain. Deleting some N-terminal residues of the alpha/beta hydrolase domain of CD26 ablated peptidase activity and greatly diminished cell surface expression. Together with previous data that CD26 peptidase activity requires the C-terminal 20 residues, this suggests that peptidase activity requires the entire alpha/beta hydrolase domain. The catalytic triad of DP8 was shown to be Ser(739)-Asp (817)-His(849). Glu(259) of DP8, a residue distant from the catalytic triad yet greatly conserved in the CD26 gene family, was shown to be required for peptidase activity. These data concord with our predicted CD26 structure, indicate that biosynthesis of a functional fragment of CD26 is difficult, and confirm the functional homology of DP8 with CD26.
ESTHER : Ajami_2003_Biochemistry_42_694
PubMedSearch : Ajami_2003_Biochemistry_42_694
PubMedID: 12534281
Gene_locus related to this paper: human-DPP8 , human-DPP9

Title : Dipeptidyl peptidase IV gene family. The DPIV family - Chen_2003_Adv.Exp.Med.Biol_524_79
Author(s) : Chen T , Ajami K , McCaughan GW , Gorrell MD , Abbott CA
Ref : Advances in Experimental Medicine & Biology , 524 :79 , 2003
Abstract : We have identified three novel members of the DPIV gene family using database mining approaches. Recombinant DP8 shares a post-proline dipeptidyl aminopeptidase activity with the closely related enzymes DPIV and FAP. The similarities between DP8, DP9 and DPIV in tissue expression pattern suggest a potential role for DP8 and DP9 in liver disease, T cell activation and immune function. The role of the two novel enzymes DP8 and DP9 and the other non-enzyme member DPL2 in human disease will be the focus of further studies.
ESTHER : Chen_2003_Adv.Exp.Med.Biol_524_79
PubMedSearch : Chen_2003_Adv.Exp.Med.Biol_524_79
PubMedID: 12675227
Gene_locus related to this paper: human-DPP10

Title : Cloning, expression and chromosomal localization of a novel human dipeptidyl peptidase (DPP) IV homolog, DPP8 - Abbott_2000_Eur.J.Biochem_267_6140
Author(s) : Abbott CA , Yu DM , Woollatt E , Sutherland GR , McCaughan GW , Gorrell MD
Ref : European Journal of Biochemistry , 267 :6140 , 2000
Abstract : Dipeptidyl peptidase (DPP) IV has roles in T-cell costimulation, chemokine biology, type-II diabetes and tumor biology. Fibroblast activation protein (FAP) has been implicated in tumor growth and cirrhosis. Here we describe DPP8, a novel human postproline dipeptidyl aminopeptidase that is homologous to DPPIV and FAP. Northern-blot hybridization showed that the tissue expression of DPP8 mRNA is ubiquitous, similar to that of DPPIV. The DPP8 gene was localized to chromosome 15q22, distinct from a closely related gene at 19p13.3 which we named DPP9. The full-length DPP8 cDNA codes for an 882-amino-acid protein that has about 27% identity and 51% similarity to DPPIV and FAP, but no transmembrane domain and no N-linked or O-linked glycosylation. Western blots and confocal microscopy of transfected COS-7 cells showed DPP8 to be a 100-kDa monomeric protein expressed in the cytoplasm. Purified recombinant DPP8 hydrolyzed the DPPIV substrates Ala-Pro, Arg-Pro and Gly-Pro. Thus recombinant DPP8 shares a postproline dipeptidyl aminopeptidase activity with DPPIV and FAP. DPP8 enzyme activity had a neutral pH optimum consistent with it being nonlysosomal. The similarities between DPP8 and DPPIV in tissue expression pattern and substrates suggests a potential role for DPP8 in T-cell activation and immune function.
ESTHER : Abbott_2000_Eur.J.Biochem_267_6140
PubMedSearch : Abbott_2000_Eur.J.Biochem_267_6140
PubMedID: 11012666
Gene_locus related to this paper: human-DPP8

Title : Two highly conserved glutamic acid residues in the predicted beta propeller domain of dipeptidyl peptidase IV are required for its enzyme activity - Abbott_1999_FEBS.Lett_458_278
Author(s) : Abbott CA , McCaughan GW , Gorrell MD
Ref : FEBS Letters , 458 :278 , 1999
Abstract : Dipeptidyl peptidase IV (DPP IV) is a member of the prolyl oligopeptidase family and modifies the biological activities of certain chemokines and neuropeptides by cleaving their N-terminal dipeptides. This paper reports the identification and possible significance of a novel conserved sequence motif Asp-Trp-(Val/Ile/Leu)-Tyr-Glu-Glu-Glu (DW(V/I/L)YEEE) in the predicted beta propeller domain of the DPP IV-like gene family. Single amino acid point mutations in this motif identified two glutamates, at positions 205 and 206, as essential for the enzyme activity of human DPP IV. This observation suggests a novel role in proteolysis for residues of DPP IV distant from the Ser-Asp-His catalytic triad.
ESTHER : Abbott_1999_FEBS.Lett_458_278
PubMedSearch : Abbott_1999_FEBS.Lett_458_278
PubMedID: 10570924

Title : Genomic organization, exact localization, and tissue expression of the human CD26 (dipeptidyl peptidase IV) gene - Abbott_1994_Immunogenetics_40_331
Author(s) : Abbott CA , Baker E , Sutherland GR , McCaughan GW
Ref : Immunogenetics , 40 :331 , 1994
Abstract : CD26 is a lymphocyte cell surface antigen which is increased during T-cell activation and is also expressed in other tissues. It is an atypical serine protease belonging to the prolyl oligopeptidase family. CD26 has been implicated in a variety of biological functions including T-cell activation, cell-to-cell adhesion, and recently in HIV infection. This paper describes, through the isolation and partial sequencing of eight human CD26 genomic clones, the first information on the genomic organization of the prolyl oligopeptidase family. We have established that the human CD26 gene spans approximately 70 kilobases (kb) and contains 26 exons, ranging in size from 45 base pairs (bp) to 1.4 kb. The nucleotides that encode the serine recognition site (G-W-S-Y-G) are split between two exons. This clearly distinguishes the genomic organization of the prolyl oligopeptidase family from that of the classical serine protease family. The 5' flanking domain of the CD26 gene contains neither a TATA box nor a CAAT box, but a 300 bp region extremely rich in C and G (72%) contains potential binding sites for several transcriptional factors. The human CD26 gene encodes two messages sized at about 4.2 and 2.8 kb. These are both expressed at high levels in the placenta and kidney and at moderate levels in the lung and liver. Only the 4.2 kb mRNA was expressed at low levels in skeletal muscle, heart, brain, and pancreas. Fluorescence in situ hybridization on metaphase chromosome spreads located the human CD26 gene to the long arm of chromosome 2(2q24.3).
ESTHER : Abbott_1994_Immunogenetics_40_331
PubMedSearch : Abbott_1994_Immunogenetics_40_331
PubMedID: 7927537
Gene_locus related to this paper: human-DPP4