[Preparation and identification of polyclonal antibodies against Moraxella catarrhalis UspA1].

To prepare polyclonal antibodies (PcAb) against UspA1 of Moraxella catarrhalis (Mc), we used bioinformatic analysis to determine the surface exposed region in this protein that holds the antigen epitopes. Then the corresponding coding sequences for this fragment was artificially synthesized according to the codon usage of Escherichia coli. The gene fragment was then subcloned into the prokaryotic expression vector pET-28a(+) and expressed in E. coli rosseta (DE3), and then the recombinant UspA1-His proteins were purified. Two New Zealand white rabbits were immunized with this protein to prepare antiserum. The resulting PcAb was then purified from the antiserum with Protein A affinity column. The results of fluorescence antibody assay, enzyme linked immunosorbent assay and Western blotting analysis showed that the PcAb could specifically recognize the surface exposed region of UspA1 on Mc. The preparation of the PcAb laid a foundation of further development of rapid detection technique for M. catarrhalis.

UB-311, a novel UBITh® amyloid ß peptide vaccine for mild Alzheimer's disease.

INTRODUCTION: A novel amyloid ß (Aß) synthetic peptide vaccine (UB-311) has been evaluated in a first-in-human trial with patients of mild-to-moderate Alzheimer's disease. We describe translational research covering vaccine design, preclinical characterization, and phase-I clinical trial with supportive outcome that advances UB-311 into an ongoing phase-II trial. METHODS: UB-311 is constructed with two synthetic Aß1-14-targeting peptides (B-cell epitope), each linked to different helper T-cell peptide epitopes (UBITh®) and formulated in a Th2-biased delivery system. The hAPP751 transgenic mouse model was used to perform the proof-of-concept study. Baboons and macaques were used for preclinical safety, tolerability, and immunogenicity evaluation. Patients with mild-to-moderate Alzheimer's disease (AD) were immunized by intramuscular route with 3 doses of UB-311 at weeks 0, 4, and 12, and monitored until week 48. Safety and immunogenicity were assessed per protocol, and preliminary efficacy was analyzed by Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), Mini-Mental State Examination (MMSE), and Alzheimer's Disease Cooperative Study-Clinician's Global Impression of Change (ADCS-CGIC). RESULTS: UB-311 covers a diverse genetic background and facilitates strong immune response with high responder rate. UB-311 reduced the levels of Aß1-42 oligomers, protofibrils, and plaque load in hAPP751 transgenic mice. Safe and well-tolerated UB-311 generated considerable site-specific (Aß1-10) antibodies across all animal species examined. In AD patients, UB-311 induced a 100% responder rate; injection site swelling and agitation were the most common adverse events (4/19 each). A slower rate of increase in ADAS-Cog from baseline to week 48 was observed in the subgroup of mild AD patients (MMSE ≥ 20) compared with the moderate AD subgroup, suggesting that UB-311 may have a potential of cognition improvement in patients with early stage of Alzheimer's dementia. DISCUSSION: The UBITh® platform can generate a high-precision molecular vaccine with high responder rate, strong on-target immunogenicity, and a potential of cognition improvement, which support UB-311 for active immunotherapy in early-to-mild AD patients currently enrolled in a phase-II trial (NCT02551809).

Mitochondria targeted peptides protect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine neurotoxicity.

A large body of evidence suggests that mitochondrial dysfunction and oxidative damage play a role in the pathogenesis of Parkinson's disease (PD). A number of antioxidants have been effective in animal models of PD. We have developed a family of mitochondria-targeted peptides that can protect against mitochondrial swelling and apoptosis (SS peptides). In this study, we examined the ability of two peptides, SS-31 and SS-20, to protect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxicity in mice. SS-31 produced dose-dependent complete protection against loss of dopamine and its metabolites in striatum, as well as loss of tyrosine hydroxylase immunoreactive neurons in substantia nigra pars compacta. SS-20, which does not possess intrinsic ability in scavenging reactive oxygen species, also demonstrated significant neuroprotective effects on dopaminergic neurons of MPTP-treated mice. Both SS-31 and SS-20 were very potent (nM) in preventing MPP+ (1-methyl-4-phenylpyridinium)-induced cell death in cultured dopamine cells (SN4741). Studies with isolated mitochondria showed that both SS-31 and SS-20 prevented MPP+-induced inhibition of oxygen consumption and ATP production, and mitochondrial swelling. These findings provide strong evidence that these neuroprotective peptides, which target both mitochondrial dysfunction and oxidative damage, are a promising approach for the treatment of PD.

Mitochondrial targeting with antioxidant peptide SS-31 prevents mitochondrial depolarization, reduces islet cell apoptosis, increases islet cell yield, and improves posttransplantation function.

Apoptotic cell death is a defined pathway for islet cell demise, and mitochondrial dysfunction contributes to islet cell apoptosis. The hypothesis that the novel peptide D-Arg-2', 6'-dimethyltyrosine-Lys-Phe-NH2 (SS-31), previously shown to target inner mitochondrial membrane and prevent oxidative damage of neuronal cells and other cell types, optimizes pancreatic islet isolation and improves posttransplantation function in recipients with diabetes was investigated. Herein is demonstrated that SS-31 readily penetrates intact mouse islets, preserves mitochondrial polarization, reduces islet cell apoptosis, and increases islet cell yield. Optimization of islet isolation is demonstrable after SS-31 pretreatment of islet (pancreas) donor mice and with the addition of SS-31 to reagents that are used in the isolation of mouse islets. The supplementation of in vitro culture medium with SS-31 reduced islet cell apoptosis and increased the viability of human islets, as ascertained by dual-parameter flow cytometry analysis. In a stringent marginal islet cell mass transplantation model (200 mouse islets transplanted under the renal capsule of syngeneic diabetic mice) and using islets that were derived from old mice (>24 wk), SS-31 treatment was associated with prompt and sustained normoglycemia, whereas the untreated islet graft recipients remained diabetic. Our data suggest a novel strategy to optimize islet isolation and reduce the need for multiple pancreata to achieve insulin independence in the recipient with type 1 diabetes. Because SS-31 was effective with "extended" islet donors, it is hypothesized that the antioxidant SS-31 may serve to increase the pool of eligible organ donors.

Mitochondria-targeted peptide prevents mitochondrial depolarization and apoptosis induced by tert-butyl hydroperoxide in neuronal cell lines.

Oxidative stress and mitochondrial oxidative damage have been implicated in aging and many common diseases. Mitochondria are a primary source of reactive oxygen species (ROS) in the cell, and are particularly susceptible to oxidative damage. Oxidative damage to mitochondria results in mitochondrial permeability transition (MPT), mitochondrial depolarization, further ROS production, swelling, and release of cytochrome c (cyt c). Cytosolic cyt c triggers apoptosis by activating the caspase cascade. In the present work, we examined the ability of a novel cell-penetrating, mitochondria-targeted peptide antioxidant in protecting against oxidant-induced mitochondrial dysfunction and apoptosis in two neuronal cell lines. Treatment with tert-butyl hydroperoxide (tBHP) for 24 h resulted in lipid peroxidation and significant cell death via apoptosis in both N2A and SH-SY5Y cells, with phosphatidylserine translocation, nuclear condensation and increased caspase activity. Cells treated with tBHP showed significant increase in intracellular ROS, mitochondrial depolarization and reduced mitochondrial viability. Concurrent treatment with <1 nM SS-31 (D-Arg-Dmt-Lys-Phe-NH2; Dmt = 2',6'-dimethyltyrosine) significantly decreased intracellular ROS, increased mitochondrial potential, and prevented tBHP-induced apoptosis. The remarkable potency of SS-31 can be explained by its extensive cellular uptake and selective partitioning into mitochondria. Intracellular concentrations of [3H]SS-31 were 6-fold higher than extracellular concentrations. Studies using isolated mitochondria revealed that [3H]SS-31 was concentrated approximately 5000-fold in the mitochondrial pellet. By concentrating in the inner mitochondrial membrane, SS-31 is localized to the site of ROS production, and can therefore protect against mitochondrial oxidative damage and further ROS production. SS-31 represents a novel platform of mitochondria-targeted antioxidants with broad therapeutic potential.

Fluorescent dyes alter intracellular targeting and function of cell-penetrating tetrapeptides.

Fluorescent labels are commonly used to investigate the mechanisms of cellular uptake and intracellular distribution of cell-penetrating peptides. However, labels such as fluorescein and rhodamine are relatively large and very lipophilic and may significantly alter physicochemical properties of small peptides. To minimize the impact of the fluorescent probe on a tetrapeptide, we substituted one of the amino acids (Lys4) in a tetrapeptide ([Dmt1]DALDA, Dmt-D-Arg-Phe-Lys-NH2 where Dmt = 2',6'-dimethyltyrosine) with two different fluorescent amino acids (beta-dansyl-L-alpha,beta-diaminopropionic acid (dnsDap4) or beta-anthraniloyl-L-alpha,beta-diaminopropionic acid (atnDap4)). Initial studies with confocal laser scanning microscopy (CLSM) showed very different localization patterns for the two fluorescent analogs, with [Dmt1,atnDap4]DALDA showing mitochondrial localization and [Dmt1,dnsDap4]DALDA showing diffuse cytoplasmic localization. Studies with isolated mouse liver mitochondria suggested that [Dmt1,dnsDap4]DALDA targeted the mitochondrial matrix resulting in mitochondrial depolarization, opening of the permeability transition pore, mitochondrial swelling, and rapid release of the peptide into the cytoplasm. In contrast, [Dmt1,atnDap4]DALDA was retained in the inner mitochondrial membrane and did not induce mitochondrial swelling. Furthermore, [Dmt1,atnDap4]DALDA protected mitochondria against Ca2+-induced swelling. Importantly, the unlabeled parent peptide [Dmt1]DALDA behaved like [Dmt1,atnDap4]DALDA and was mitoprotective. These findings suggest that experimental results obtained with fluorescent labels must be interpreted with caution, and the use of multiple fluorophores, together with confirmation using the original or radiolabeled molecule, is recommended.

Cell-permeable peptide antioxidants targeted to inner mitochondrial membrane inhibit mitochondrial swelling, oxidative cell death, and reperfusion injury.

Reactive oxygen species (ROS) play a key role in promoting mitochondrial cytochrome c release and induction of apoptosis. ROS induce dissociation of cytochrome c from cardiolipin on the inner mitochondrial membrane (IMM), and cytochrome c may then be released via mitochondrial permeability transition (MPT)-dependent or MPT-independent mechanisms. We have developed peptide antioxidants that target the IMM, and we used them to investigate the role of ROS and MPT in cell death caused by t-butylhydroperoxide (tBHP) and 3-nitropropionic acid (3NP). The structural motif of these peptides centers on alternating aromatic and basic amino acid residues, with dimethyltyrosine providing scavenging properties. These peptide antioxidants are cell-permeable and concentrate 1000-fold in the IMM. They potently reduced intracellular ROS and cell death caused by tBHP in neuronal N(2)A cells (EC(50) in nm range). They also decreased mitochondrial ROS production, inhibited MPT and swelling, and prevented cytochrome c release induced by Ca(2+) in isolated mitochondria. In addition, they inhibited 3NP-induced MPT in isolated mitochondria and prevented mitochondrial depolarization in cells treated with 3NP. ROS and MPT have been implicated in myocardial stunning associated with reperfusion in ischemic hearts, and these peptide antioxidants potently improved contractile force in an ex vivo heart model. It is noteworthy that peptide analogs without dimethyltyrosine did not inhibit mitochondrial ROS generation or swelling and failed to prevent myocardial stunning. These results clearly demonstrate that overproduction of ROS underlies the cellular toxicity of tBHP and 3NP, and ROS mediate cytochrome c release via MPT. These IMM-targeted antioxidants may be very beneficial in the treatment of aging and diseases associated with oxidative stress.

Transcellular transport of a highly polar 3+ net charge opioid tetrapeptide.

Oligopeptides are generally thought to have poor permeability across biological membranes. Recent studies, however, suggest significant distribution of [Dmt1]DALDA (Dmt-D-Arg-Phe-Lys-NH2; Dmt is 2',6'-dimethyltyrosine), a 3+ net charge opioid peptide, to the brain and spinal cord after subcutaneous administration. Peptide transporters (PEPT1 and PEPT2) play a major role in the uptake of di- and tripeptides across cell membranes, but their ability to transport tetrapeptides is not clear. The purpose of this study was to determine whether [Dmt1]DALDA can translocate across Caco-2 cell monolayers and whether PEPT1 plays a role in the uptake process. Our results show that [3H][Dmt1]DALDA can readily translocate across Caco-2 cells, with a permeability coefficient estimated to be 1.24 x 10(-5) cm/s. When incubated with Caco-2 cells, [3H][Dmt1]DALDA was detected in cell lysates by 5 min. The internalization of [Dmt1]DALDA was confirmed visually with a fluorescent [Dmt1]DALDA analog (H-Dmt-D-Arg-Phe-dnsDap-NH2; dnsDap is beta-dansyl-L-alpha,beta-diaminopropionic acid). The uptake of [3H][Dmt1]DALDA was concentration-dependent but temperature- and pH-independent. Treatment with diethylpyrocarbonate (DEPC) inhibited [14C]glycine-sarcosine uptake but increased [3H][Dmt1]DALDA uptake 34-fold. These findings suggest that PEPT1 is not involved in [Dmt1]DALDA internalization. [Dmt1]DALDA uptake was also observed in SH-SY5Y, human embryonic kidney 293, and CRFK cells, and was independent of whether the cells expressed opioid receptors. The efflux of [3H][Dmt1]DALDA from Caco-2 cells was temperature-dependent and was inhibited by DEPC, but was not affected by verapamil, an inhibitor of P-glycoprotein. These data show transcellular translocation of a highly polar 3+ charge tetrapeptide and suggest that [Dmt1]DALDA may not only distribute across the blood-brain barrier but also it may even have reasonable oral absorption.