The Access Technology Program of the Indiana Clinical Translational Sciences Institute (CTSI): A model to facilitate access to cutting-edge technologies across a state

INTRODUCTION

Access to cutting-edge technologies is essential for investigators to advance translational research. The Indiana Clinical and Translational Sciences Institute (CTSI) spans three major and preeminent universities, four large academic campuses across the state of Indiana, and is mandate to provide best practices to a whole state.

METHODS

To address the need to facilitate the availability of innovative technologies to its investigators, the Indiana CTSI implemented the Access Technology Program (ATP). The activities of the ATP, or any program of the Indiana CTSI, are challenged to connect technologies and investigators on the multiple Indiana CTSI campuses by the geographical distances between campuses (1-4 hr driving time).

RESULTS

Herein, we describe the initiatives developed by the ATP to increase the availability of state-of-the-art technologies to its investigators on all Indiana CTSI campuses, and the methods developed by the ATP to bridge the distance between campuses, technologies, and investigators for the advancement of clinical translational research.

CONCLUSIONS

The methods and practices described in this publication may inform other approaches to enhance translational research, dissemination, and usage of innovative technologies by translational investigators, especially when distance or multi-campus cultural differences are factors to efficient application.

Cathepsin E is a specific marker of dysplasia in APC mouse intestine

Transcriptional profiling of APC(Min/+) mouse intestinal epithelial tissue has revealed that cathepsin E (catE) manifests high relative expression in adenomas and carcinomas relative to normal epithelium. Real-time RT-PCR data presented previously confirm the presence of catE transcript in APC(Min/+) adenomatous cells compared with samples derived from normal APC(Min/+) and wild-type tissue. At the protein level, strong, highly specific immunohistochemical staining for catE is displayed in dysplastic lesions of APC(Min/+) mice. Using Western immunoblot analyses, it was additionally established that the urine of tumor-bearing mice contains higher levels of the monomeric form of catE than their wild-type counterparts. These results authenticate the relationship between transcript abundance and protein levels in transformed tissue and suggest potential utility for catE as a marker for the inception and progression of intestinal cancers.

Structure-function analysis of the streptokinase amino terminus (residues 1-59)

Streptokinase (SK) binds to plasminogen (Pg) to form a complex that converts substrate Pg to plasmin. Residues 1-59 of SK regulate its capacity to induce an active site in bound Pg by a nonproteolytic mechanism and to activate substrate Pg in a fibrin-independent manner. We analyzed 24 SK mutants to better define the functional properties of SK-(1-59). Mutations within the alphabeta1 strand (residues 17-26) of SK completely prevented nonproteolytic active site induction in bound Pg and rendered SK incapable of protecting plasmin from inhibition by alpha2-antiplasmin. However, when fibrin-bound, the activities of alphabeta1 strand mutants were similar to that of wild-type (WT) SK and resistant to alpha2-antiplasmin. Mutation of Ile1 of SK also prevented nonproteolytic active site induction in bound Pg. However, unlike alphabeta1 strand mutants, the functional defect of Ile1 mutants was not relieved by fibrin, and complexes of Ile1 mutants and plasmin were resistant to alpha2-antiplasmin. Plasmin enhanced the activities of alphabeta1 strand and Ile1 mutants, suggesting that SK-plasmin complexes activated mutant SK.Pg complexes by hydrolyzing the Pg Arg561-Val562 bond. Mutational analysis of Glu39 of SK suggested that a salt bridge between Glu39 and Arg719 of Pg is important, but not essential, for nonproteolytic active site induction in Pg. Deleting residues 1-59 rendered SK dependent on plasmin and fibrin to generate plasminogen activator (PA) activity. However, the PA activity of SK-(60-414) in the presence of fibrin was markedly reduced compared with WT SK. Despite its reduced PA activity, the fibrinolytic potency of SK-(60-414) was greater than that of WT SK at higher (but not lower) SK concentrations due to its capacity to deplete plasma Pg. These studies define mechanisms by which the SK alpha domain regulates rapid active site induction in bound Pg, contributes to the resistance of the SK-plasmin complex to alpha2-antiplasmin, and controls fibrin-independent Pg activation.

A total fibrinogen deficiency is compatible with the development of pulmonary fibrosis in mice

In addition to their well-known roles in hemostasis, fibrinogen (Fg) and fibrin (Fn) have been implicated in a number of other physiological and pathophysiological events. One of these involves the fibroproliferative response after acute lung injury, which is the focus of the current study. Mice with a total Fg deficiency (FG(-/-)) were generated by breeding heterozygous (FG(+/-)) pairs, each of which contained an allele with a targeted deletion of its Fg-gamma-chain gene. The resulting FG(-/-) animals did not possess detectable plasma Fg. FG(-/-) mice were then used to assess the roles of Fg and Fn in a bleomycin-induced acute lung injury model. Intratracheal administration of bleomycin in wild-type and FG(-/-) mice resulted in equivalent deposition of interstitial collagen and fibrotic lesions at days 7 and 14 after administration. This indicates that Fg and/or Fn are not essential for the development of bleomycin-induced pulmonary fibrosis.

Cloning and characterization of a cDNA encoding murine coagulation factor X

The cDNA encoding murine coagulation factor X (fX) was isolated and reconstructed from a lambdaZap cDNA library generated from murine liver mRNA. The cDNA contains 1486 bases starting at the 5'-translation initiation codon. It includes an open reading frame of 1443 nucleotides, followed by an 18 residue 3' nontranslated sequence downstream of the first stop codon. and a 3' poly(A) tail. The translation product is composed of a 40-amino acid signal/propeptide region followed by a 441-residue mature protein. The latter is highly homologous to that of human and rat fX. All protein domains of human and rat fX are strictly conserved in mouse fX. The cDNA coding for mouse fX has been expressed in human embryonic kidney 293 cells and generates fX activity measured in a clotting assay using human fX-deficient plasma.

Selective inhibition by kringle 5 of human plasminogen on endothelial cell migration, an important process in angiogenesis

Angiogenesis is a multi-step process that includes endothelial cell proliferation, migration, basement membrane degradation, and new lumen organization. Angiostatin, an internal fragment of plasminogen comprising the first four triple disulfide-linked kringle structures, is one of the most potent endogenous angiogenesis inhibitors described to date. The kringle 5 domain of plasminogen, which shares high sequence homology with the four kringles of angiostatin, was previously shown to antagonize endothelial cell growth. We now describe that the recombinant kringle 5 of human plasminogen inhibits endothelial cell migration with an IC50 (concentration for half maximal inhibition) of approximately 500 nM. We demonstrate that the lysine-binding sites of kringle 5 may not be involved in its anti-migratory activities. The anti-migratory activity of kringle 5 is similar to that of angiostatin. Kringle 5 also shows selective inhibition on endothelial cells as opposed to other cell types. Relative to its native form, reduced kringle 5 displays a significant increase in anti-migratory activity, implying that the kringle conformation may shield kringle 5 from effectively interacting with endothelial cells. This report thus constitutes the first demonstration that kringle 5 of plasminogen is a selective inhibitor for endothelial cell migration.

High-level secretion in Pichia pastoris and biochemical characterization of the recombinant kringle 2 domain of tissue-type plasminogen activator

The kringle 2 (K2) domain of tissue-type plasminogen activator (tPA) has been expressed in Pichia pastoris cell lines GSI 15 and KM71. This construct contained a hexahistidine sequence at the C-terminus of the kringle to aid in purification by immobilized metalion-affinity chromatography. The exact amino acid sequence of the isolated kringle was EAEAYV-[K2tPA]SR(H)6, where [K2tPA] represents amino acid sequence residues C1-C82 of the kringle domain (residues 180-261 of tPA). The clones of the yeast transformants provided large amounts of the recombinant (r)-[K2tPA]-containing polypeptide at levels that allowed ready purification of several hundred mg from shake flasks and near-gram levels from a high-biomass fermenter. Purification of the kringle domain directly from cell-conditioned media was accomplished in a single step by either immobilized Ni(+)-affinity chromatography or lysine-Sepharose affinity chromatography. N-linked glycans were present on approx. 30% of this yeast-expressed material, at N5 of the kringle (corresponds to N11 of the particular construct, N184 of full-length tPA). The expressed recombinant kringle recognized a conformation-specific monoclonal antibody generated against tPA that is directed to the K2 domain of the protein, interacted properly with various omega-amino acid ligands, and showed signature conformational properties when studied by differential scanning calorimetry and high-resolution 1H-NMR. The results demonstrate that the P. pastoris system can be employed to obtain large amounts of secreted and properly folded kringle domains.