17 research outputs found
Zinc deficiency disrupts pain signaling promoting nociceptive but not inflammatory pain in mice
Abstract Zinc (Zn) is an essential micronutrient involved in the physiology of nervous system and pain modulation. There is little evidence for the role of nutritional Zn alternations to the onset and progression of neuropathic (NP) and inflammatory pain. The study investigated the effects of a zinc restricted diet on the development of pain. Weaned mice were submitted to a regular (38 mg/kg of Zn) or Zn deficient (11 mg/kg of Zn) diets for four weeks, pain responses evaluated (mechanical, cold and heat allodynia; formalin- and carrageenan-induced inflammatory hypernociception), plasma and tissues collected for biochemical and metabolomic analysis. Zn deficient diet inhibited animal growth (37%) and changed mice sensitivity pattern, inducing an intense allodynia evoked by mechanical, cold and heat stimulus for four weeks. The inflammatory pain behavior of formalin test was drastically reduced or absent when challenged by an inflammatory stimulus. Zn restriction also reduce plasma TNF, increase neuronal activation, oxidative stress, indicating a disruption of the immune response. Liver metabolomic analyses suggest a downregulation of lipid metabolism of arachidonic acid. Zn restriction since weaned disrupts pain signaling considerably and reduce inflammatory pain. Zn could be considered a predisposing factor for the onset of chronic pain such as painful neuropathies
Update on the pharmacology of calcitonin/CGRP family of peptides:IUPHAR Review 25
The calcitonin/calcitonin gene-related peptide (CGRP) family of peptides includes calcitonin, α and ÎČ CGRP, amylin, adrenomedullin (AM) and adrenomedullin 2/intermedin (AM2/IMD). Their receptors consist of one of two G protein-coupled receptors (GPCRs), the calcitonin receptor (CTR) or the calcitonin receptor-like receptor (CLR). Further diversity arises from heterodimerisation of these GPCRs with one of three receptor activity-modifying proteins (RAMPs). This gives the CGRP receptor (CLR/RAMP1), the AM1 and AM2 receptors (CLR/RAMP2 or RAMP3) and the AMY1, AMY2 and AMY3 receptors (CTR/RAMPs1-3 complexes, respectively). Apart from the CGRP receptor, there are only peptide antagonists widely available for these receptors and these have limited selectivity, thus defining the function of each receptor in vivo remains challenging. Further challenges arise from the probable co-expression of CTR with the CTR/RAMP complexes and species-dependent splice variants of the CTR (CT(a) and CT(b)). Furthermore, the AMY1(a) receptor is activated equally well by both amylin and CGRP and the preferred receptor for AM2/IMD has been unclear. However, there are clear therapeutic rationales for developing agents against the various receptors for these peptides. For example many agents targeting the CGRP system are in clinical trials and pramlintide, an amylin analogue, is an approved therapy for insulin-requiring diabetes. This review provides an update on the pharmacology of the calcitonin family of peptides by members of the corresponding subcommittee of the International Union of Basic and Clinical Pharmacology and colleagues
Monoconjugation of Human Amylin with Methylpolyethyleneglycol
<div><p>Amylin is a pancreatic hormone cosecreted with insulin that exerts unique roles in metabolism and glucose homeostasis. The therapeutic restoration of postprandial and basal amylin levels is highly desirable in diabetes mellitus. Protein conjugation with the biocompatible polymer polyethylene glycol (PEG) has been shown to extend the biological effects of biopharmaceuticals. We have designed a PEGylated human amylin by using the aminoreactive compound methoxylpolyethylene glycol succinimidyl carbonate (mPEGsc). The synthesis in organic solvent resulted in high yields of monoPEGylated human amylin, which showed large stability against aggregation, an 8 times increase in half-life <i>in vivo</i> compared to the non-conjugated amylin, and pharmacological activity as shown by modulation of cAMP production in MCFâ7 cell line, decrease in glucagon and modulation of glycemia following subcutaneous administration in mice. Altogether these data reveal the potential use of PEGylated human amylin for the restoration of fasting amylin levels.</p></div
BZ043, a novel long-acting amylin analog, reduces gastric emptying, food intake, glycemia and insulin requirement in streptozotocin-induced diabetic rats
Antiviral, Cytoprotective, and Anti-Inflammatory Effect of <i>Ampelozizyphus amazonicus</i> Ducke Ethanolic Wood Extract on Chikungunya Virus Infection
Chikungunya fever, a debilitating disease caused by Chikungunya virus (CHIKV), is characterized by a high fever of sudden onset and an intense arthralgia that impairs individual regular activities. Although most symptoms are self-limited, long-term persistent arthralgia is observed in 30â40% of infected individuals. Currently, there is no vaccine or specific treatment against CHIKV infection, so there is an urgent need for the discovery of new therapeutic options for CHIKF chronic cases. This present study aims to test the antiviral, cytoprotective, and anti-inflammatory activities of an ethanol extract (FF72) from Ampelozizyphus amazonicus Ducke wood, chemically characterized using mass spectrometry, which indicated the major presence of dammarane-type triterpenoid saponins. The major saponin in the extract, with a deprotonated molecule ion m/z 897 [M-H]â, was tentatively assigned as a jujubogenin triglycoside, a dammarane-type triterpenoid saponin. Treatment with FF72 resulted in a significant reduction in both virus replication and the production of infective virions in BHK-21-infected cells. The viability of infected cells was assessed using an MTT, and the result indicated that FF72 treatment was able to revert the toxicity mediated by CHIKV infection. In addition, FF72 had a direct effect on CHIKV, since the infectivity was completely abolished in the presence of the extract. FF72 treatment also reduced the expression of the major pro-inflammatory mediators overexpressed during CHIKV infection, such as IL-1ÎČ, IL-6, IL-8, and MCP-1. Overall, the present study elucidates the potential of FF72 to become a promising candidate of herbal medicine for alphaviruses infections
Amylin self-assembly and interaction with co-receptors.
<p>Free murine amylin or PEGylated human amylin were assayed for binding with (<b>A</b>) murine amylin, (<b>B</b>) CTRâ1 and (<b>C</b>) RAMPâ3 by fluorescence anisotropy of fluorescein labeled molecular partners. Assays were conducted in PBS, pH 7.4, 25°C, in the presence of 50 nM FITC-labelled proteins (amylin, CTRâ1 or RAMPâ3). Ex 480 nm, Em 520 nm, filter 515 nm. The raw data can be found in <b><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0138803#pone.0138803.s005" target="_blank">S2 File</a></b>.</p
Amylin and PEG structures.
<p><b>a)</b> Aminoacid sequence of the human and murine amylin. In bold are the different aminoacid. Notice the similarity in sequence from aminoacid 1 to 17. The N-terminus is the Lys1, which comprises the α- and Δ-aminogroup, the two unique primary aminogroups in amylin targeted for PEGylation. <b>b)</b> Chemical structure of the methoxyl PEG N-hydroxylsuccinimide (NHS) carbonate. <b>c)</b> Structure of the human amylin. Human amylin (from NMR structure, PDB ID 2KB8) is represented in ribbons colored from aminoacid 1 (blue) to 37 (red). Notice the two aminogroups at the top left side of the representation.</p
Amylin-stimulated generation of cAMP in MCFâ7 cells.
<p>Non-conjugated or PEGylated amylin were assayed for activity in cell by means of stimulation of production of cAMP in MCFâ7 cell line. Lines represent best adjust of experimental data with logistic function. Human amylin EC50 = 35.2 ± 7.5 nM, PEGylated human amylin EC50 = 30.8 ± 6.7 nM. The raw data can be found in <b><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0138803#pone.0138803.s005" target="_blank">S2 File</a></b>.</p
Pharmacologic evaluation of PEGylated human amylin.
<p><b>a)</b> Pharmacokinetics. Non-conjugated and PEGylated human amylin were injected to two separated groups of swiss male mice by subcutaneous administration and the decay in plasma concentration was evaluated. Continuous lines are best fitting of single-exponential decay function to data. <b>b)</b> Modulation of glucagon. Swiss male mice were administered with 10 ÎŒg PEGylated human amylin and the serum glucagon was monitored over time. * P<0.05. <b>c)</b> Modulation of glycemia. Swiss male mice (8 weeks old; fasting for 6 h before intervention and throughout the experiment) received by subcutaneous injection regular insulin (0.3 IU/kg body weight) alone (closed circles; n = 5) or in combination with free murine amylin (open circles; 400 ÎŒg/kg body weight; n = 5) or PEGylated human amylin (closed inverted triangles; 400 ÎŒg/kg body weight, expressed as peptide fraction; n = 5) and glycemia was monitored in the tail tip of free, conscientious mice. The activity of PEGylated human amylin showed significant difference from control (Insulin-R): * P<0.05, **P<0.01. The raw data can be found in <b><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0138803#pone.0138803.s005" target="_blank">S2 File</a></b>.</p
Physical stability of the free and the PEGylated human amylin.
<p>Human amylin was subjected to aggregation at 25°C and monitored for fibril formation by ThT fluorescence <b>(a)</b> for up to 12h at varying pH (closed symbols, free non-conjugated human amylin; open symbols, PEGylated human amylin) and <b>(b)</b> for up to 7 days in PBS pH 7.4, and the products of these aggregation kinetic isotherms were further evaluated by transmission electron microscopy (TEM) as follow: <b>(c)</b> free human amylin; <b>(d)</b> PEGylated human amylin; <b>(e)</b> free PEG. Scale bar = 200 nm. The raw data can be found in <b><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0138803#pone.0138803.s005" target="_blank">S2 File</a></b>.</p