Safety and pharmacokinetics of the orally available antiprionic compound PRI-002: A single and multiple ascending dose phase I study.

Introduction: PRI-002 is an orally available anti-amyloid beta (Aβ) prionic compound developed for direct disassembly of toxic Aβ oligomers relevant to Alzheimer's disease.

Methods: Two placebo-controlled clinical phase I trials with oral dosing of PRI-002 were conducted in healthy young subjects: A single ascending dose trial (4, 12, 36, 108, or 320 mg PRI-002 or placebo) in 40 participants followed by a multiple ascending dose study with daily 160 mg PRI-002 for 14 days or 320 mg for 28 days in 24 participants. The main objectives were safety, tolerability, and evaluation of pharmacokinetic (PK) parameters.

Continuous Subcutaneous Delivery of Proline-Rich Antimicrobial Peptide Api137 Provides Superior Efficacy to Intravenous Administration in a Mouse Infection Model.

Apidaecins are cationic, proline-rich antimicrobial peptides originally isolated from honeybees and exhibit high Gram-negative activity by inhibiting bacterial protein translation. Pharmacokinetics of apidaecin derivative Api137 was studied using single and multiple intravenous or subcutaneous injections as well as continuous subcutaneous infusion and correlated to its efficacy in a lethal murine infection model. Survival rates of infected CD-1 mice were monitored and Api137 and its metabolites were quantified in plasma of uninfected CD-1 mice and Sprague Dawley rats using reversed-phase chromatography coupled online to mass spectrometry.

Oncocin Onc72 is efficacious against antibiotic-susceptible Klebsiella pneumoniae ATCC 43816 in a murine thigh infection model.

Oncocins and apidaecins are short proline-rich antimicrobial peptides (PrAMPs) representing novel antibiotic drug lead compounds that kill bacteria after internalization and inhibition of intracellular targets (e.g. 70S ribosome and DnaK).

Reversing ABCB1-mediated multi-drug resistance from within cells using translocating immune conjugates.

Multi-drug resistance (MDR) is still a major cause of the eventual failure of chemotherapy in cancer treatment. Different approaches have been taken to render these cells drug sensitive. Here, we attempted sensitizing drug-resistant cells from within, using a translocating immune conjugate approach.

Short-term monotherapy in HIV-infected patients with a virus entry inhibitor against the gp41 fusion peptide.

To infect host cells, most enveloped viruses must insert a hydrophobic fusion peptide into the host cell membrane. Thus, fusion peptides may be valuable targets for developing drugs that block virus entry. We have shown previously that a natural 20-residue fragment of α(1)-antitrypsin, designated VIRus-Inhibitory Peptide (VIRIP), that binds to the gp41 fusion peptide of HIV-1 prevents the virus from entering target cells in vitro.

Synthesis of the proteinase inhibitor LEKTI domain 6 by the fragment condensation method and regioselective disulfide bond formation.

Proteinase inhibitors are of high pharmaceutical interest and are drug candidates for a variety of indications. Specific kallikrein inhibitors are important for their antitumor activity and their potential application to the treatment of skin diseases. In this study we describe the synthesis of domain 6 of the kallikrein inhibitor Lympho-Epithilial Kazal-Type Inhibitor (LEKTI) by the fragment condensation method and site-directed cystine bridge formation.

Crystallization and preliminary X-ray structural studies of human prouroguanylin.

Uroguanylin, which serves as an endogenous ligand of guanylyl cyclase C, is initially secreted in the form of a precursor, prouroguanylin. The N-terminal region of prouroguanylin interacts with the mature portion of prouroguanylin during the folding pathway. Here, a preliminary X-ray crystallographic study of prouroguanylin is presented.

N-terminal acetylation protects glucagon-like peptide GLP-1-(7-34)-amide from DPP-IV-mediated degradation retaining cAMP- and insulin-releasing capacity.

Since its discovery glucagon-like peptide-1 (GLP-1) is investigated as a treatment for type II diabetes based on its major function as insulin secretagogue. A therapeutic use is, however, limited by its short biological half-life in the range of minutes, predominantly caused via degradation catalyzed by dipeptidyl peptidase IV (DPP-IV). Therefore, we aimed to design a GLP-1 analogue exhibiting resistance against DPP-IV-catalyzed inactivation while retaining its biological activity.

Semen-derived amyloid fibrils drastically enhance HIV infection.

Sexual intercourse is the major route of HIV transmission. To identify endogenous factors that affect the efficiency of sexual viral transmission, we screened a complex peptide/protein library derived from human semen. We show that naturally occurring fragments of the abundant semen marker prostatic acidic phosphatase (PAP) form amyloid fibrils.

Discovery and optimization of a natural HIV-1 entry inhibitor targeting the gp41 fusion peptide.

A variety of molecules in human blood have been implicated in the inhibition of HIV-1. However, it remained elusive which circulating natural compounds are most effective in controlling viral replication in vivo. To identify natural HIV-1 inhibitors we screened a comprehensive peptide library generated from human hemofiltrate.

Synthesis and structure-activity relationship of beta-defensins, multi-functional peptides of the immune system.

beta-defensins are a large family of multiple disulfide-bonded peptides occurring in mammals and birds. They play an important role in the innate immune system, directly killing microbial organisms. Recent research has demonstrated that beta-defensins are important for other biological functions beyond antimicrobial effects, including inhibition of viral infection, interaction with Toll-like receptors, chemotactic effects, and sperm function.

Structure-activity relation of human beta-defensin 3: influence of disulfide bonds and cysteine substitution on antimicrobial activity and cytotoxicity.

Human beta-defensins form a group of cysteine-rich antimicrobial peptides which have been found in epithelial tissue and, more recently, in the male genital tract. They play a role in the defense against microbial pathogens in innate immunity and display additional chemotactic functions in the adaptive immune system. An important characteristic of antimicrobial peptides is that they also exhibit toxic potential on eukaryotic cells.

Side chain contributions to the interconversion of the topological isomers of guanylin-like peptides.

The peptide hormones guanylin and uroguanylin are ligands of the intestinal guanylyl cyclase-C (GC-C) that is involved in the regulation of epithelial water and electrolyte transport. The small peptides contain 15 and 16 amino acids, respectively, and two disulfide bonds with a 1-3/2-4 connectivity. This structural feature causes the unique existence of two topological isoforms for each peptide in an approximate 3:2 ratio, with only one of the isoforms exhibiting GC-C-activating potential.

Engineering disulfide bonds of the novel human beta-defensins hBD-27 and hBD-28: differences in disulfide formation and biological activity among human beta-defensins.

Human beta-defensins comprise a large number of peptides that play a functional role in the innate and adaptive immune system. Recently, clusters of new beta-defensin genes with predominant expression in testicular tissue have been discovered on different chromosomes by bioinformatics. beta-Defensins share a common pattern of three disulfides that are essential for their biological effects.

Stability and cleavage conditions of (2-furyl)-L-alanine-containing peptides.

The furyl group of (2-furyl)-L-alanine-containing peptides obtained from Fmoc solid-phase synthesis is partially degraded to several by-products during the final TFA-mediated deprotection in the presence of cation scavengers such as ethanedithiol and propanedithiol. The major by-product corresponds to a bis-dithioacetale formed after acidic hydrolysis of the furyl group. We examined several cleavage conditions and found that cleavage cocktails containing water and triisopropylsilane or 3,6-dioxa-1,8-octanedithiol (DODT) in trifluoroacetic acid are sufficient to minimize the side reaction.

Exploiting natural peptide diversity: novel research tools and drug leads.

During the course of evolution, nature has developed a vast number of peptides in all living and past species that display an exceeding diversity of structure and biological effects, such as hormonal and enzyme-controlling activity, communication between cells, and participation in host defence. Sensitive mass spectrometric technologies have been introduced and facilitate access to new natural peptides, even in trace amounts, and allow the quantitative determination of the peptide status of cells, organs and whole organisms (peptidomics). Among the large number of new biologically active peptides identified from an increasing variety of natural sources, regulators of ion channels, chemoattractants, protease inhibitors, metabolism-related hormones, cytotoxins, and antimicrobials have been found.

Functional analysis of chemically synthesized derivatives of the human CC chemokine CCL15/HCC-2, a high affinity CCR1 ligand.

The CCL15 is a human CC chemokine that activates the receptors, CCR1 and CCR3. Unlike other chemokines, it contains an unusually long N-terminal domain of 31 amino acids preceding the first cysteine residue and a third disulfide bond. To elucidate the functional role of distinct structural determinants, a series of sequential amino-terminal truncated and point-mutated CCL15 derivatives as well as mutants lacking the third disulfide bond and the carboxy-terminal alpha-helix were synthesized using 9-fluorenylmethoxycarbonyl (Fmoc) chemistry.

The leader peptide of MMTV Env precursor localizes to the nucleoli in MMTV-derived T cell lymphomas and interacts with nucleolar protein B23.

We have previously described two nucleolar proteins, named p14 and p21, in MMTV-induced T cell lymphomas. These proteins were identified by a monoclonal antibody (M-66) generated from a nontumorigenic, immunogenic variant of S49 T cell lymphoma. While p14 was common to several MMTV-derived T cell lymphomas, p21 was found only in highly tumorigenic variants of S49 cells.

N-terminal proopiomelanocortin acts as a mitogen in adrenocortical tumor cells and decreases adrenal steroidogenesis.

There is evidence that proopiomelanocortin (POMC)-derived peptides other than ACTH are involved in pituitary-dependent adrenal growth. We have synthesized the human N-terminal POMC fragment 1-28-POMC with the disulfide bridges in the correct position between cysteine residues 2-24 and 8-20 and studied the activity of these peptides in adrenocortical tumor cells in vitro. 1-28-POMC stimulated cell proliferation in human NCI-h295 and mouse Y-1 adrenal cancer cell lines and also in primary cultures of bovine adrenocortical cells in a concentration-dependent manner.

Homologous proteins with different folds: the three-dimensional structures of domains 1 and 6 of the multiple Kazal-type inhibitor LEKTI.

We have determined the solution structures of recombinant domain 1 and native domain 6 of the multi-domain Kazal-type serine proteinase inhibitor LEKTI using multi-dimensional NMR spectroscopy. While two of the 15 potential inhibitory LEKTI domains contain three disulfide bonds typical of Kazal-type inhibitors, the remaining 13 domains have only two of these disulfide bridges. Therefore, they may represent a novel type of serine proteinase inhibitor.

Isolation and biochemical characterization of LEAP-2, a novel blood peptide expressed in the liver.

The human genome contains numerous genes whose protein products are unknown in terms of structure, interaction partner, expression, and function. To unravel the function of these orphan genes, it is of particular value to isolate native forms of protein and peptide products derived from these genes. From human blood ultrafiltrate, we characterized a novel gene-encoded, cysteine-rich, and cationic peptide that we termed liver-expressed antimicrobial peptide 2 (LEAP-2).

Chemical synthesis of beta-defensins and LEAP-1/hepcidin.

A large and steadily growing subfamily of antimicrobially active peptides of animals and plants is formed by the defensins, which are highly disulfide-bonded, cationic peptides with a molecular mass of about 4 kDa. The synthesis of the human beta-defensins 1 and 2 (hBD-1, hBD-2) as well as of the novel murine beta-defensins 7 and 8 (mBD-7 and mBD-8) is reported. The peptides were synthesized by solid-phase peptide synthesis using fluorenylmethoxycarbonyl chemistry.

Hemofiltrate CC chemokine 1[9-74] causes effective internalization of CCR5 and is a potent inhibitor of R5-tropic human immunodeficiency virus type 1 strains in primary T cells and macrophages.

Proteolytic processing of the abundant plasmatic human CC chemokine 1 (HCC-1) generates a truncated form, HCC-1[9-74], which is a potent agonist of CCR1, CCR3, and CCR5; promotes calcium influx and chemotaxis of T lymphoblasts, monocytes, and eosinophils; and inhibits infection by CCR5-tropic human immunodeficiency virus type 1 (HIV-1) isolates. In the present study we demonstrate that HCC-1[9-74] interacts with the second external loop of CCR5 and inhibits replication of CCR5-tropic HIV-1 strains in both primary T cells and monocyte-derived macrophages. Low concentrations of the chemokine, however, frequently enhanced the replication of CCR5-tropic HIV-1 isolates but not the replication of X4-tropic HIV-1 isolates.

The 15-domain serine proteinase inhibitor LEKTI: biochemical properties, genomic organization, and pathophysiological role.

Proteinases are involved in specific and non-specific proteolytic reactions, and participate in many pathophysiological processes. Normally, they are regulated by endogenously produced proteinase inhibitors which, thus, represent lead structures for the development of therapeutics. We succeeded in partially isolating and cloning a novel human serine proteinase inhibitor which, according to its structure and the expression pattern of the corresponding gene, was termed lympho-epithelial Kazal-type-related inhibitor (LEKTI).