Interaction of the synthetic immunomodulatory dipeptide bestim with murine macrophages and thymocytes

The tritium-labeled dipeptide bestim (gamma-D-Glu-L-Trp) with a specific activity of 45 Ci/mmol was obtained by high-temperature solid-state catalytic isotope exchange. It was found that [3H]bestim binds with a high affinity to murine peritoneal macrophages (Kd 2.1 +/- 0.1 nM) and thymocytes (Kd 3.1 +/- 0.2 nM), as well as with plasma membranes isolated from these cells (Kd 18.6 +/- 0.2 and 16.7 +/- 0.3 nM, respectively). The specific binding of [3H]bestim to macrophages and thymocytes was inhibited by the unlabeled dipeptide thymogen (L-Glu-L-Trp) (Ki 0.9 +/- 0.1 and 1.1 +/- 0.1 nM, respectively). After treatment with trypsin, macrophages and thymocytes lost the ability to bind [3H]bestim. Bestim in the concentration range of 10(-10) to 10(-6) M reduced the adenylate cyclase activity in the membranes of murine macrophages and thymocytes.     

Influence of interstitial fluid dynamics on growth and therapy of angiogenic tumor. Analysis by mathematical model

We have developed a spatially distributed mathematical model of angiogenic tumor growth in tissue with account of interstitial fluid dynamics and bevacizumab monotherapy. In this model the process of neovascularization is initiated by tumor cells in a state of metabolic stress, vascular endothelial growth factor (VEGF) being its main mediator. The model takes into consideration the convection flows arising in dense tissue due to active proliferation and migration of tumor cells as well as interstitial fluid inflow from blood vascular system, its outflow through lymphatic system and redistribution in the area of tumor growth. The work considers the diffusive approximation of interstitial fluid dynamics in tumor and normal tissue. Numerical study of the model showed that in absence of therapy a peritumoral edema is formed due to the increase of interstitial fluid inflow from angiogenic capillaries. In the case of rapid interstitial fluid outflow through lymphatic system and its fast transport from necrotic zone to normal tissue the regimes of full growth stop are observed in case of low-invasive tumor. Under bevacizumab monotherapy the peritumoral edema vanishes and low-invasive tumor may not only decelerate its growth, but also start shrinking for a large range of parameters.     

Human IL-36RA production in <Emphasis Type="Italic">Escherichia coli</Emphasis> with coexpression of <Emphasis Type="Italic">E. coli</Emphasis> methionine aminopeptidase. I. Comparison of IL-36RA production in different strains

Generalized pustular psoriasis (GPP) is a rare, sometimes lethal, form of psoriasis caused by series of mutations in the interleukin-36 receptor antagonist (IL-36RA) gene associated with its reduced expression or activity. Administration of exogenous IL-36RA can be a potent therapeutic approach to treating GPP and other forms of psoriasis. Since cleavage of the starting N-formylmethionine residue from the N-terminal end is needed for full biological activity of IL-36RA, we have developed a technique for producing IL-36RA lacking N-formylmethionine residue in E. coli. We have created a series of plasmids carrying the E. coli methionine aminopeptidase (MAP) gene under the control of different promoters for coexpression of IL-36RA and MAP and tested their effect on IL-36RA production. The highest production of IL-36RA with <3% of unprocessed molecules with uncleaved N-terminal formylmethionine residue has been shown for E. coli strain carrying the MAP gene under the control of arabinose-inducible promoter.     

The LKEKK synthetic peptide as a ligand of rat intestinal epithelial cell membranes

A tritium-labeled synthetic LKEKK pentapeptide corresponding to the sequences 16–20 of human thymosin-α₁ and 131–135 of human interferon-α₂ was obtained with a specific activity of 28 Ci/mmol. [³H]LKEKK was found to bind with high affinity (K _d 3.7 ± 0.3 nM) to the membranes isolated from epithelial cells of rat small intestinal mucosa. The trypsin treatment of the membranes did not affect the binding, thus supporting the nonprotein nature of the peptide receptor. The binding of the labeled peptide was inhibited by unlabeled thymosin-α₁, interferon-α₂, and cholera toxin B subunit (K _i 4.2 ± 0.4, 3.5 ± 0.3, and 4.7 ± 0.3 nM respectively). The pentapeptide did not affect the adenylate cyclase activity within the concentration range of 1–1000 nM.     

Glutamate antibodies repress expression of <Emphasis Type="Italic">Dffb</Emphasis> gene in brain of rats in experimental Alzheimer’s disease

The rat model of Alzheimer’s disease including injection of neurotoxic fragment of β-amyloid protein Aβ_25–35 into giant-cell nuclei basalis of Meynert was used for experiments. We have investigated the influence of glutamate antibodies administered intranasally in a dose of 300 μg/kg after 1 h of the mentioned alteration on the level of expression of Dffb mRNA. Dffb gene codes caspase-dependent DNase, which participates in the internucleosomal fragmentation of genome DNA during apoptosis. On the third day after the injection of Aβ_25–35, we obtained a significant decrease in Dffb gene expression in the prefrontal cortex (37% decrease) and hippocampus (62% decrease) in the group of experimental animals compared to the control group. In the hypothalamus, there were no such differences. Seemingly, the repressing action of glutamate antibodies on the mRNA expression of the Dffb gene reflects the stabilization of processes that take place in the brain cells during experimental Alzheimer’s disease; meanwhile, the intensity of the apoptotic death of neurons and glial cells decreases.     

Protein transduction domain peptide mediates delivery to the brain via the blood-brain barrier in Drosophila melanogaster

The phenomenon of protein transduction represents internalization of short peptides known as protein transduction domains (PTD) by cells. It is widely used in the development of new preparations for treatment of various brain disorders. However, the drug discovery process is limited by lack of simple and reliable models of blood brain barrier (BBB). These models should meet two main criteria: they should be applicable for testing of large numbers of samples simultaneously reproduce the physiological and functional characteristics of mammalian (including) human BBB. The major goal of this study was to estimate the BBB-crossing ability of known PTD-peptides using Drosophila melanogaster BBB as the model. We demonstrate here that after abdominal administration the PTD-peptide penetratin, derived from a Drosophila Antennapedia homeodomain protein can cross Drosophila and deliver the apoE mimetic peptide exhibiting neuroprotective properties.