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peptide science.

Inhibition of cellular and systemic inflammation cues in human bronchial epithelial cells by melanocortin-related peptides: mechanism of KPV action and a role for MC3R agonists.

Int J Physiol Pathophysiol Pharmacol

Stephen C Land

Chemokine signaling from airway epithelium regulates macrophage recruitment to the lung in inflammatory diseases such as asthma. This study investigates the mechanism by which the α-melanocyte stimulating hormone-derived tripeptide, KPV, and the agonist of the dominant melanocortin receptor in airway epithelium (MC3R), γ-melanocyte stimulating hormone (γ-MSH), suppress inflammation in immortalised human bronchial airway epithelium.

Terminal signal: anti-inflammatory effects of α-melanocyte-stimulating hormone related peptides beyond the pharmacophore.

Adv Exp Med Biol

Thomas Brzoska, Markus Böhm, Andreas Lügering +2 more

During the last two decades a significant number of investigations has established the fact that α-Melanocyte-stimulating hormone (α-MSH) is a potent anti-inflammatory mediator. The anti-inflammatory effects of α-MSH can be elicited via melanocortin receptors (MC-Rs) broadly expressed in a number of tissues ranging from the central nervous system to cells of the immune system and on resident somatic cells of peripheral tissues. α-MSH affects various pathways regulating inflammatory responses such as NF-κB activation, expression of adhesion molecules, inflammatory cytokines, chemokine receptors, T-cell proliferation and activity and inflammatory cell migration. In vivo α-MSH has been shown to be anti-inflammatory as well in animal models of fever, irritant and allergic contact dermatitis, cutaneous vasculitis, fibrosis, in ocular, gastrointestinal, brain and allergic airway inflammation and arthritis. A broad range of effects of α-MSH exerted beyond the field of inflammation, its pigmentory capacity being only the most visible aspect, has been one of the major impediments limiting the use of α-MSH in human inflammatory disorders. Interestingly KPV, C-terminal tripeptide of α-MSH, which lacks the entire sequence motif required for binding to any of the known MC-Rs, retains almost all of the anti-inflammatory capacity of the full hormone, but in its activities display a lack of any pigmentory action. While the exact signaling mechanism utilized by KPV and related peptides currently is unknown it has been demonstrated already that significant similarities between anti-inflammatory signaling of α-MSH and those short peptides exist. These α-MSH related tripeptides thus may be useful alternatives for anti-inflammatory peptide therapy. KdPT, a derivative of KPV corresponding to IL-1β(193-195), currently is emerging as another tripeptide with potent anti-inflammatory effects. A more limited spectrum of biologic activities, potentially advantageous physicochemical, pharmacokinetic and pharmacodynamic properties as well as the expectation of low costs for pharmaceutical production make these agents interesting candidates for the treatment of immune-mediated inflammatory skin and bowel diseases, allergic asthma and arthritis.

Injection of duck recombinant follistatin fusion protein into duck muscle tissues stimulates satellite cell proliferation and muscle fiber hypertrophy.

Appl Microbiol Biotechnol

He-he Liu, Ji-wen Wang, Hai-yue Yu +6 more

Follistatin (FST) can inhibit the expression of myostatin, which is a predominant inhibitor of muscle development. The potential application of myostatin-based technology has been prompted in different ways in agriculture. We previously constructed an expression vector of duck FST and isolated the FST fusion protein. After the protein was purified and refolded, it was added to the medium of duck myoblasts cultured in vitro. The results show that the 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide value of the myoblasts in the duck FST treatment group is higher than that in the control group, which indicates that the duck FST fusion protein exhibits the biological activities that can accelerate myoblast proliferation. To further investigate the roles of duck FST on muscle development, we injected the protein into the duck muscle tissues in vivo. The results show that both the duck muscle fiber cross-sectional area and the satellite cell activation frequency are influenced more in the FST treatment group than they are in the control group. In addition to these phenomena, expression of MyoD and Myf5 were increased, and the expression of myostatin was decreased. Together, these results suggest the potential for using duck FST fusion protein to inhibit myostatin activity and subsequently to enhance muscle growth in vivo. The mechanism by which FST regulates muscle development in the duck is similar to that in mammals and fishes.

Age-related loss of muscle mass and strength.

J Aging Res

Geoffrey Goldspink

Age-related muscle wasting and increased frailty are major socioeconomic as well as medical problems. In the quest to extend quality of life it is important to increase the strength of elderly people sufficiently so they can carry out everyday tasks and to prevent them falling and breaking bones that are brittle due to osteoporosis. Muscles generate the mechanical strain that contributes to the maintenance of other musculoskeletal tissues, and a vicious circle is established as muscle loss results in bone loss and weakening of tendons. Molecular and proteomic approaches now provide strategies for preventing age-related muscle wasting. Here, attention is paid to the role of the GH/IGF-1 axis and the special role of the IGFI-Ec (mechano growth factor/MGF) which is derived from the IGF-I gene by alternative splicing. During aging MGF levels decline but when administered MGF activates the muscle satellite (stem) cells that "kick start" local muscle repair and induces hypertrophy.

Influence of membrane ion channel in pituitary somatotrophs by hypothalamic regulators.

Cell Calcium

Seung-Kwon Yang, Frederik Steyn, Chen Chen

The secretion of growth hormone (GH) from somatotrophs located within the anterior pituitary gland is stimulated by endogenous hypothalamic growth hormone-releasing hormone (GHRH) and the GH secretagogue (GHS) ghrelin, and inhibited by somatotropin-releasing inhibitory factor (SRIF, also known as somatostatin). These factors bind to specific G-protein-coupled receptors on the cell membrane, and directly or indirectly modify the properties of ion channels and second messenger systems. Ultimately this results in a change in intracellular free Ca(2+) concentration ([Ca(2+)](i)) and the secretion of GH. Somatotrophs possess a variety of ion channels on their membranes, and modification of these ion channels, especially Ca(2+), K(+), and Na(+) channels, is tightly linked to intracellular Ca(2+) levels and therefore hormone secretion. Various issues regarding receptor distribution, role of ion channels, alteration of membrane potential, and involvement of intracellular signaling system in the control of GH secretion are discussed in this review. In particular, this work will focus on ion channels and [Ca(2+)](i) in somatotrophs.

[Effect of delta-sleep inducing peptide on the functional activity of some organs and tissues of rats during physiological aging].

Adv Gerontol

T I Bondarenko, E A Maĭboroda, I I Mikhaleva +1 more

The authors show that exogenous delta-sleep inducing peptide (DSIP) injected subcutaneously to the rats in the age of 2-24 months of postnatal development in a dose of 100 mg/kg of animal body weight in courses for 5 consecutive days every month, has a hepatoprotective effect. DSIP does not affect the functional activity of the pancreas, and is not involved in the regulation of calcium homeostasis in the physiological aging of the organism.

Immunoaffinity purification of peptide hormones prior to liquid chromatography-mass spectrometry in doping controls.

Methods

Andreas Thomas, Wilhelm Schänzer, Philippe Delahaut +1 more

For most peptide hormones prohibited in elite sports the concentrations in plasma or urine are very low (pg/mL). Accordingly, hyphenated purification and enrichment steps prior to mass spectrometric detection are required to obtain sufficient doping control assays. Immunoaffinity purification in combination with nano-scale liquid chromatography coupled to high resolution/high accuracy mass spectrometry was found to have the potential of providing the necessary sensitivity and unambiguous specificity to produce reliable results. With the presented methodology 12 prohibited peptides (porcine insulin, Novolog, Apidra, Lantus DesB30-32 metabolite, Humalog and human insulin, Synacthen (synthetic ACTH analogue), luteinizing hormone-releasing hormone (LH-RH), growth hormone releasing hormone (GH-RH(1-29)) and CJC-1295 (GH-RH analogue), LongR(3)-IGF-1 and IFG-1) were simultaneously purified from plasma/serum or urine. With limits of detection for each target compound ranging in the low pg/mL level (urine), the method enables the determination of urinary peptides at physiologically relevant concentrations. For each class of peptides an appropriate antibody and a respective internal standard was implemented ensuring robust analysis conditions. Due to the fast and simple sample preparation procedure (∼25 samples per day) and the fact that all materials are commercial available, the implementation of the methodology to laboratories from other analytical fields (forensics, pharmacokinetic sciences, etc.) is enabled.

[The role of opioid system in peculiarities of anti-anxiety effect of peptide anxiolytic selank].

Eksp Klin Farmakol

I I Kozlovskiĭ, L A Andreeva, M M Kozlovskaia +2 more

Peculiarities of the anxiolytic effects of selank (heptapeptide analog of taftsin) under reduced activity of opioid system upon acute administration of naloxone have been studied in BALB/C and C57BL/6 inbred mice with high and low levels of anxiety, with passive and active emotional stress reaction phenotypes in the open field (OF) test. Selank (0.25 mg/kg, i.p.) per se exhibited anxiolytic effect in BALB/C mice by increasing the general locomotor activity, with no effects on the behavior of C57BL/6 mice in the OF test. Naloxone (1.0 mg/kg, i.p.) per se evoked swift runaway in OF peripheral areas in BALB/C mice while "freezing" the reaction in C57BL/6 mice with active response to stress under the same conditions. Pretreatment with naloxone attenuated the sensitivity to selank in BALB/C mice whereas the response to anxiolytic effects of peptide was increased in C57BL/6 mice. The data obtained reveal a new target for selank in CNS and indicate significance of the activity of enkephalin-opioid system in individual sensitivity to selank.

Early exercise promotes positive hippocampal plasticity and improves spatial memory in the adult life of rats.

Hippocampus

Sérgio Gomes da Silva, Nicolas Unsain, Daniel Hugo Mascó +9 more

There is a great deal of evidence showing the capacity of physical exercise to enhance cognitive function, reduce anxiety and depression, and protect the brain against neurodegenerative disorders. Although the effects of exercise are well documented in the mature brain, the influence of exercise in the developing brain has been poorly explored. Therefore, we investigated the morphological and functional hippocampal changes in adult rats submitted to daily treadmill exercise during the adolescent period. Male Wistar rats aged 21 postnatal days old (P21) were divided into two groups: exercise and control. Animals in the exercise group were submitted to daily exercise on the treadmill between P21 and P60. Running time and speed gradually increased over this period, reaching a maximum of 18 m/min for 60 min. After the aerobic exercise program (P60), histological and behavioral (water maze) analyses were performed. The results show that early-life exercise increased mossy fibers density and hippocampal expression of brain-derived neurotrophic factor and its receptor tropomyosin-related kinase B, improved spatial learning and memory, and enhanced capacity to evoke spatial memories in later stages (when measured at P96). It is important to point out that while physical exercise induces hippocampal plasticity, degenerative effects could appear in undue conditions of physical or psychological stress. In this regard, we also showed that the exercise protocol used here did not induce inflammatory response and degenerating neurons in the hippocampal formation of developing rats. Our findings demonstrate that physical exercise during postnatal development results in positive changes for the hippocampal formation, both in structure and function.

[Noopept in the treatment of mild cognitive impairment in patients with stroke].

Zh Nevrol Psikhiatr Im S S Korsakova

A V Amelin, A Iu Iliukhina, A A Shmonin

Noopept is a neuroprotector and nootropics. Literature data revealed the treatment effect of noopept on mild cognitive impairment in patients with discirculatory encephalopathy. The present open prospective study included 60 patients with stroke treated with noopept during 12 months. Cognitive functions were assessed before and after treatment using neuropsychological tests. An analysis of MMSE scores and lateral and categorical associations revealed the significant improvement of cognitive functions after 2 months in patients of the main group compared to the controls. The global assessment of efficacy revealed the mild improvement in the main group while no changes were found in the control group. The results have demonstrated that noopept, used in dose 20 mg daily during 2 months, improves cognitive functions in stroke patients and has a high level of safety.

Nanobiology and physiology of growth hormone secretion.

Exp Biol Med (Maywood)

Lloyd L Anderson, Colin G Scanes

Growth hormone (GH) secretion is controlled by hypothalamic releasing hormones from the median eminence together with hormones and neuropeptides produced by peripheral organs. Secretion of GH involves movement of secretory vesicles along microtubules, transient 'docking' with the porosome in the cell membrane and subsequent release of GH. Release of GH is stimulated by GH releasing hormone (GHRH) and inhibited by somatostatin (SRIF). Ghrelin may be functioning to stimulate GH release from somatotropes acting via the GH secretagogue (GHS) receptor (GHSR). However, recent physiological studies militate against this. In addition, ghrelin does influence GH release acting within the hypothalamus. Release of GH from the somatotropes involves the GH-containing secretory granules moving close to the cell surface followed by transitory fusion of the secretory granules with the porosomes located in multiple secretory pits in the cell membrane. Other peptides/proteins can influence GH secretion, particularly in species of non-mammalian vertebrates.

[Peptidergic modulation of the hippocampus synaptic activity].

Ross Fiziol Zh Im I M Sechenova

V G Skrebitskiĭ, R V Kondratenko, I S Povarov +1 more

Effects of two newly synthesized nootropic and anxiolytic dipeptides: Noopept and Selank on inhibitory synaptic transmission in hippocampal CA1 pyramidal cells were investigated using patch-clamp technique in whole-cell configuration. Bath application of Noopept (1 microM) or Selank (2 microM) significantly increased the frequency of spike-dependent spontaneous m1PSCs, whereas spike-independent mlPSCs remained unchanged. It was suggested that both peptides mediated their effect sue to activation of inhibitory interneurons terminating on CA1 pyramidal cells. Results of current clamp recording of inhibitory interneurons residing in stratum radiatum confirmed this suggestion, at least for Noonent.

The type 1 insulin-like growth factor receptor (IGF-IR) pathway is mandatory for the follistatin-induced skeletal muscle hypertrophy.

Endocrinology

S Kalista, O Schakman, H Gilson +5 more

Myostatin inhibition by follistatin (FS) offers a new approach for muscle mass enhancement. The aim of the present study was to characterize the mediators responsible for the FS hypertrophic action on skeletal muscle in male mice. Because IGF-I and IGF-II, two crucial skeletal muscle growth factors, are induced by myostatin inhibition, we assessed their role in FS action. First, we tested whether type 1 IGF receptor (IGF-IR) is required for FS-induced hypertrophy. By using mice expressing a dominant-negative IGF-IR in skeletal muscle, we showed that IGF-IR inhibition blunted by 63% fiber hypertrophy caused by FS. Second, we showed that FS caused the same degree of fiber hypertrophy in wild-type and IGF-II knockout mice. We then tested the role of the signaling molecules stimulated by IGF-IR, in particular the Akt/mammalian target of rapamycin (mTOR)/70-kDa ribosomal protein S6 kinase (S6K) pathway. We investigated whether Akt phosphorylation is required for the FS action. By cotransfecting a dominant-negative form of Akt together with FS, we showed that Akt inhibition reduced by 65% fiber hypertrophy caused by FS. Second, we evaluated the role of mTOR in FS action. Fiber hypertrophy induced by FS was reduced by 36% in rapamycin-treated mice. Finally, because the activity of S6K is increased by FS, we tested its role in FS action. FS caused the same degree of fiber hypertrophy in wild-type and S6K1/2 knockout mice. In conclusion, the IGF-IR/Akt/mTOR pathway plays a critical role in FS-induced muscle hypertrophy. In contrast, induction of IGF-II expression and S6K activity by FS are not required for the hypertrophic action of FS.

[Sleep peptides in experimental models of epilepsy].

Glas Srp Akad Nauka Med

O Stanojlović, D Hrnčić, A Rašić-Marković +3 more

Molecular identification of ghrelin receptor (GHS-R1a) and its functional role in the gastrointestinal tract of the guinea-pig.

Peptides

Takio Kitazawa, Tatsuro Nakamura, Atsuki Saeki +3 more

Ghrelin stimulates gastric motility in vivo in the guinea-pig through activation of growth hormone secretagogue receptor (GHS-R). In this study, we identified GHS-R1a in the guinea-pig, and examined its distribution and cellular function and compared them with those in the rat. Effects of ghrelin in different regions of gastrointestinal tract were also examined. GHS-R1a was identified in guinea-pig brain cDNA. Amino acid identities of guinea-pig GHS-R1a were 93% to horses and 85% to dogs. Expression levels of GHS-R1a mRNA were high in the pituitary and hypothalamus, moderate in the thalamus, cerebral cortex, pons, medulla oblongata and olfactory bulb, and low in the cerebellum and peripheral tissues including gastrointestinal tract. Comparison of GHS-R1a expression patterns showed that those in the brain were similar but the expression level in the gastrointestinal tract was higher in rats than in guinea-pigs. Guinea-pig GHS-R1a expressed in HEK 293 cells responded to rat ghrelin and GHS-R agonists. Rat ghrelin was ineffective in inducing mechanical changes in the stomach and colon but caused a slight contraction in the small intestine. 1,1-Dimethyl-4-phenylpiperazinium and electrical field stimulation (EFS) caused cholinergic contraction in the intestine, and these contractions were not affected by ghrelin. Ghrelin did not change spontaneous and EFS-evoked [(3)H]-efflux from [(3)H]-choline-loaded ileal strips. In summary, guinea-pig GHS-R1a was identified and its functions in isolated gastrointestinal strips were characterized. The distribution of GHS-R1a in peripheral tissues was different from that in rats, suggesting that the functional role of ghrelin in the guinea-pig is different from that in other animal species.

Effect of SOM230 (pasireotide) on corticotropic cells: action in dogs with Cushing's disease.

Neuroendocrinology

Victor Castillo, Marily Theodoropoulou, Johanna Stalla +7 more

SOM230 (pasireotide) is a multiligand somatostatin (SRIF) analog able to bind to somatostatin receptor (SSTR) subtypes 1, 2, 3 and 5, and trigger antisecretory and antiproliferative signaling cascades. Canines have become in vivo models to test the pharmacological treatment of corticotropinomas because they frequently develop Cushing's disease in a spontaneous manner, due to adrenocorticotropic hormone (ACTH)-producing pituitary adenomas. Different levels of expression of SSTR2 and SSTR5 have been shown in both mouse AtT20 cells and canine tumoral corticotropinoma cells. The objective of this study was to evaluate whether SOM230 controls both tumor cell growth and hormone synthesis, therefore controlling the disease. SOM230 was tested in dogs suffering from Cushing's disease (10 animals were treated continuously during 6 months, and another 10 were treated with 3 cycles consisting of 2 months of treatment followed by a 2-month rest period). A significant decrease in ACTH, urinary cortisol creatinine ratio, adenoma size (magnetic nuclear resonance) and improvement of clinical signs were obtained, without side effects. AtT20 cells treated with SOM230 suppressed pro-opiomelanocortin (POMC) promoter activity through SSTR2, via the G(i) α-subunit, and reduced Nur77/Nurr1 transcriptional activity. We conclude that SOM230, in addition to its well-described antisecretory effects, inhibits, as shown in AtT20 cells, ACTH synthesis at the POMC transcriptional level, an effect mediated mainly through SSTR2, and limits tumor growth. The controlled Cushing's disease in the dogs that received the treatment indicates that SOM230 has a potential therapeutic use in humans suffering from Cushing's disease.

[Current possibilities in the treatment of posttraumatic cognitive disturbances].

Zh Nevrol Psikhiatr Im S S Korsakova

M M Odinak, S V Vorob'ev, V Iu Lobzin +2 more

The β isoenzyme of Ca(2+)/calmodulin-dependent kinase type II as possible mediator of somatostatin functions in pituitary tumour cells.

Gen Physiol Biophys

Davide Cervia

Somatostatin or somatostatin release inhibiting factor (SRIF) analogues are indicated for the treatment of somatotropinomas that hypersecrete growth hormone (GH). Indeed, SRIF inhibits intracellular Ca(2+) concentration ([Ca(2+)](i)), thus allowing the inhibition of GH secretion. In the present study, our hypothesis was that Ca(2+)/calmodulin-dependent kinase type II (CaMKII), a multifunctional serine/threonine protein kinase, is part of those signalling mechanisms mediating SRIF functions. All four CaMKII isoenzymes (termed α, β, γ and δ) are expressed in rat somatotroph GC cells, although only CaMKIIβ is inhibited by SRIF at both mRNA and protein levels. Similarly to SRIF, the specific knockdown of CaMKIIβ by RNA interference induces a decrease of [Ca(2+)](i). The effects of SRIF and those of CaMKIIβ knockdown are non-additive. These results are confirmed by the pharmacological blockade of CAMKII. We also observed that, similarly to SRIF, the specific knockdown of CaMKIIβ induces a decrease of both GH content/secretion. These results raise the hypothesis that CaMKIIβ may mediate, at least in part, the SRIF-induced control of [Ca(2+)](i). In addition, CaMKIIβ seems to play a positive role in maintaining the exocytosis of GH. Our data provide a framework for better elucidating the pathophysiological role of SRIF transduction network in somatotropinomas.

[Effects of different neuromediators and regulatory peptides on the impulse activity of neurons in the superior vestibular nucleus].

Aviakosm Ekolog Med

V V Iasnetsov, V A Pravdivtsev, V G Motin +2 more

The microelectrode technique and microiontophoresis of physiologically active substances in experiments with cats immobilized with the muscle relaxants made it clear that different classical neuromediators (acetylcholine, norepinephrine, gamma-aminobutyric acid (GABA) and others), as well as regulatory peptides (enkephalins, thyrotropin-releasing hormone (TRH), vasoactive interstitial peptide (VIP), somatostatin (SS) and others) can exert a direct effect on the majority (61 to 100%) of neurons in the superior vestibular nucleus (SVN). The inhibiting effect of enkephalins, VIP and SS on the neurons impulse activity remained essentially unchanged by L-glutamate. Also, enkephalins, VIP and SS were found to amplify the inhibiting action of GABA and glycine. Consequently, these substances can fulfill the role of SVN neuromediators and/or neuromodulators.

C-terminal amino acids of alpha-melanocyte-stimulating hormone are requisite for its antibacterial activity against Staphylococcus aureus.

Antimicrob Agents Chemother

Madhuri Singh, Kasturi Mukhopadhyay

Alpha-melanocyte-stimulating hormone (α-MSH) is an endogenous neuropeptide that is known for its anti-inflammatory and antipyretic activities. We recently demonstrated that α-MSH possesses staphylocidal activity and causes bacterial membrane damage. To understand the role of its amino acid sequences in the staphylocidal mechanism, in the present study we investigated the antimicrobial activities of different fragments of α-MSH, i.e., α-MSH(6-13), α-MSH(11-13), and α-MSH(1-5), and compared them with that of the entire peptide. Our results showed that peptides containing the C-terminal region of α-MSH, namely, α-MSH(6-13) and α-MSH(11-13), efficiently killed >90% of both methicillin-sensitive and -resistant Staphylococcus aureus cells in the micromolar range and ∼50% of these cells in the nanomolar range; their efficiency was comparable to that of the entire α-MSH, whereas the peptide containing the N-terminal region, α-MSH(1-5), was found to be ineffective against S. aureus. The antimicrobial activity of α-MSH and its C-terminal fragments was not affected by the presence of NaCl or even divalent cations such as Ca2+ and Mg2+. Similar to the case for the parent peptide, α-MSH(6-13) and α-MSH(11-13) also depolarized and permeabilized Staphylococcus cells (∼70 to 80% of the cells were depolarized and lysed after 2 h of peptide exposure at micromolar concentrations). Furthermore, scanning and transmission electron microscopy showed remarkable morphological and ultrastructural changes on S. aureus cell surface due to exposure to α-MSH-based peptides. Thus, our observations indicate that C-terminal fragments of α-MSH retain the antimicrobial activity of entire peptide and that their mechanism of action is similar to that of full-length peptide. These observations are important and are critical in the rational design of α-MSH-based therapeutics with optimal efficacy.