Identification of a Receptor for Neuropeptide VGF and Its Role in Neuropathic Pain

VGF (nonacronymic) is a neuropeptide precursor that plays multiple roles in regulation of energy balance, reproduction, hippocampal synaptic plasticity, and pain. Data from a number of pain models showed significant up-regulation of VGF in sensory neurons. TLQP-21, one of the VGF-derived neuropeptides, has been shown to induce a hyperalgesic response when injected subcutaneously into the hind paw of mice. However, the precise role of VGF-derived neuropeptides in neuropathic pain and the molecular identity of the receptor for VGF-derived peptides are yet to be investigated. Here we identified gC1qR, the globular heads of the C1q receptor, as the receptor for TLQP-21 using chemical cross-linking combined with mass spectrometry analysis. TLQP-21 caused an increase in intracellular Ca²⁺ levels in rat macrophages and microglia. Inoculation of TLQP-21-stimulated macrophages into rat hind paw caused mechanical hypersensitivity. The increase in intracellular Ca²⁺ levels in macrophages was attenuated by either siRNA or neutralizing antibodies against gC1qR. Furthermore, application of the gC1qR-neutralizing antibody to rats with partial sciatic nerve ligation resulted in a delayed onset of nerve injury-associated mechanical hypersensitivity. These results indicate that gC1qR is the receptor for TLQP-21 and plays an important role in chronic pain through activation of macrophages. Because direct association between TLQP-21 and gC1qR is required for activation of macrophages and causes hypersensitivity, disrupting this interaction may be a useful new approach to develop novel analgesics.     

The occurrence and distribution of peptide- or 5-HT-containing nerves in the swimbladder of four different species of teleosts (Gadus morhua,Ctenolabrus rupestris,Anguilla anguilla,Salmo gairdneri)

Summary The innervation of the swimbladder in four different teleost species has been studied by the use of immunohistochemical methods. The teleosts examined belong to two different groups regarding their swimbladder morphology: physoclists (the cod, Gadus morhua and the goldsinny wrasse, Ctenolabrus rupestris) and physostomes (the eel, Anguilla anguilla and the rainbow trout, Salmo gairdneri). Vasoactive intestinal polypeptide-like immunoreactivity was demonstrated in nerves of the swimbladder walls of all four species, and in the gas glands of the cod and the goldsinny wrasse. Substance P-like immunoreactivity was shown in swimbladders of the cod, eel and rainbow trout but not the goldsinny wrasse. Immunoreactivity to met-enkephalin antiserum was revealed in the swimbladder walls of the eel and the goldsinny wrasse, while neurotensin-like immunoreactivity was present in the goldsinny wrasse and rainbow trout swimbladders. Neurotensin-like immunoreactivity was also seen in the gas gland of the goldsinny wrasse. 5-Hydroxytryptamine immunoreactivity was found in endocrine cells in the pneumatic duct of the eel and in the swimbladder walls of the goldsinny wrasse and the rainbow trout. In conclusion, all teleosts examined showed a very close resemblance in the peptidergic/tryptaminergic innervation of the swimbladder to that of the gut, inasmuch as the immunoreactivity present in the swimbladders always occurred in the gut of the same species.     

Wild and Rare Self-Incompatibility Allele S17 Found in 24 Sweet Cherry (Prunus avium L.) Cultivars

The pollination of self-incompatible diploid sweet cherry is determined by the S-locus alleles. We resolved the S-alleles of 50 sweet cherry cultivars grown in Estonia and determined their incompatibility groups, which were previously unknown for most of the tested cultivars. We used consensus primers SI-19/20, SI-31/32, PaConsI, and PaConsII followed by allele-specific primers and sequencing to identify sweet cherry S-genotypes. Surprisingly, 48% (24/50) of the tested cultivars, including 17 Estonian cultivars, carry the rare S-allele S₁₇, which had initially been described in wild sweet cherries in Belgium and Germany. The S₁₇-allele in Estonian cultivars could originate from ‘Leningradskaya tchernaya’ (S₆|S₁₇), which has been extensively used in Estonian sweet cherry breeding. Four studied cultivars carrying S₁₇ are partly self-compatible, whereas the other 20 cultivars with S₁₇ have not been reported to be self-compatible. The recommended pollinator of seven self-incompatible sweet cherries is of the same S-genotype, including four with S₁₇-allele, suggesting heritable reduced effectiveness of self-infertility. We classified the newly genotyped sweet cherry cultivars into 15 known incompatibility groups, and we proposed four new incompatibility groups, 64–67, for S-locus genotypes S₃|S₁₇, S₄|S₁₇, S₅|S₁₇, and S₆|S₁₇, respectively, which makes them excellent pollinators all across Europe. Alternatively, the frequency of S₁₇ might be underestimated in Eastern European populations and some currently unidentified sweet cherry S-alleles might potentially be S₁₇.

     

Wfs1 mutation makes mice sensitive to insulin-like effect of acute valproic acid and resistant to streptozocin

Valproic acid (VLP) is a widely used anticonvulsant and mood-stabilizing drug that relieves the endoplasmic reticulum (ER) stress response, a pathogenetic process related to diabetes. The aim of the present study was to evaluate whether acute valproic acid is able to interfere with glucose intolerance in two different diabetes models: The first model was a Wfs1 mutant mouse with an elevated ER stress response and the second model a streptozocin-induced diabetic mouse. VLP (300 mg/kg, i.p.) was administered to Wfs1 knockout (KO) mice and glucose tolerance test was performed 15 min later. VLP did not have an effect on the course of the glucose tolerance test in wild-type mice, while it did normalize the glucose intolerance in Wfs1 knockout mice. Acute valproic acid also lowered the blood glucose levels in streptozocin-treated mice and potentiated the effect of insulin in these mice. Thus, acute valproic acid is effective in lowering blood glucose levels possibly by potentiating insulin action in both Wfs1 KO mice and in streptozocin-induced type 1 diabetic mice.     

Nano-liquid chromatography-tandem mass spectrometry analysis of oxysterols in brain: monitoring of cholesterol autoxidation

Oxysterols are present in mammalian brain at ng/g–μg/g levels while cholesterol is present at the mg/g level. This makes oxysterol analysis of brain challenging. In an effort to meet this challenge we have developed, and validated, an isolation method based on solid phase extraction and an analytical protocol involving oxidation/derivatisation (i.e., charge-tagging) followed by nano-flow liquid chromatography (nano-LC) combined with tandem mass spectrometry utilising multi-stage fragmentation (MSⁿ). The oxidation/derivatisation method employed improves detection limits by two orders of magnitude, while nano-LC–MSⁿ provides separation of isomers and allows oxysterol quantification. Using this method 13 different oxysterols have been identified in rat brain including 24S-hydroxycholesterol, 24S,25-epoxycholesterol and 7α,26-dihydroxycholest-4-en-3-one. The level of 24S-hydroxycholesterol in rat brain was determined to be 20.3 ± 3.4 μg/g and quantitative estimates were made for the other oxysterols identified. The presence of a large excess of cholesterol over oxysterol in brain raises the problem of autoxidation during sterol isolation and sample preparation. Thus, in parallel to identification studies, the degree of cholesterol autoxidation occurring during sterol isolation and analysis has been evaluated with the aid of [²H₇]-labelled cholesterol and cholesterol autoxidation products identified.     

Acute phase proteins and oxidised low-density lipoprotein in association with ischemic stroke subtype, severity and outcome

Objectives: The goal of our study was to investigate the associations of oxidized LDL (apoB100 aldehyde-modified form) and acute phase proteins (fibrinogen, CRP) with acute ischemic stroke severity and outcome.

Materials and Methods: The study included 61 ischemic stroke patients and 64 controls. Strokes were subtyped according to TOAST criteria, the severity and outcome of stroke (at 1 year) were measured.

Results: The mean triglyceride, fibrinogen, CRP and glucose values were significantly higher among cases. The median oxLDL value for patients with large artery atherosclerosis (LAA) type of stroke was significantly higher than for other subtypes. The oxLDL values did not correlate with age, stroke severity and outcome.

Conclusions: Inflammatory markers (fibrinogen and CRP) predicted the stroke severity and outcome whereas elevation of oxLDL levels did not. Our data refer to possibility that there may exist some links between the LAA subtype of stroke and elevated oxLDL (apoB100 aldehyde-modified form).     

Cell guidance by magnetic nanowires

The phenomenon of contact guidance on thin fibers has been known since the beginning of the 20th century when Harrison studied cells growing on fibers from spider's web. Since then many studies have been performed on structured surfaces and fibers. Here we present a new way to induce guidance of cells or cell processes using magnetic nanowires. We have manufactured magnetic Ni-nanowires (200 nm in diameter and 40 μm long) with a template-based electro-deposition method. Drops of a nanowire/ethanol suspension were placed on glass cover slips. The nanowires were aligned in an external magnetic field and adhered to the cover slips after evaporation of the ethanol. When the wires had adhered, the magnetic field was removed. L929 fibroblasts and dissociated dorsal root ganglia (DRG) neurons from mice were cultured on the nanowire-coated cover slips for 24 h and 72 h respectively. The fibroblasts were affected by the aligned nanowires and displayed contact guidance. Regenerated axons also displayed contact guidance on the wires. There were no overt signs of toxicity caused by Ni-wires. Aligned magnetic nanowires can be useful for lab-on-a-chip devices and medical nerve grafts.     

Metabolic control analysis of integrated energy metabolism in permeabilized cardiomyocytes - experimental study

The main focus of this research was to apply Metabolic Control Analysis to quantitative investigation of the regulation of respiration by components of the Mitochondrial Interactosome (MI, a supercomplex consisting of ATP Synthasome, mitochondrial creatine kinase (MtCK), voltage dependent anion channel (VDAC), and tubulin) in permeabilized cardiomyocytes. Flux control coefficients (FCC) were measured using two protocols: 1) with direct ADP activation, and 2) with MtCK activation by creatine (Cr) in the presence of ATP and pyruvate kinase-phosphoenolpyruvate system. The results show that the metabolic control is much stronger in the latter case: the sum of the measured FCC is 2.7 versus 0.74 (ADP activation). This is consistent with previous data showing recycling of ADP and ATP inside the MI due to the functional coupling between MtCK and ANT and limited permeability of VDAC for these compounds, PCr being the major energy carrier between the mitochondria and ATPases. In physiological conditions, when the MI is activated, the key sites of regulation of respiration in mitochondria are MtCK (FCC = 0.93), adenine nucleotide translocase ANT (FCC = 0.95) and CoQ cytochrome c oxidoreductase (FCC = 0.4). These results show clearly that under the physiological conditions the energy transfer from mitochondria to the cytoplasm is regulated by the MI supercomplex and is very sensitive to metabolic signals.     

Complete glutathione system in probiotic Lactobacillus fermentum ME-3

There is much information about glutathione (GSH) in eukaryotic cells, but relatively little is known about GSH in prokaryotes. Without GSH and glutathione redox cycle lactic acid bacteria (LAB) cannot protect themselves against reactive oxygen species. Previously we have shown the presence of GSH in Lactobacillus fermentum ME-3 (DSM14241). Results of this study show that probiotic L. fermentum ME-3 contains both glutathione peroxidase and glutathione reductase. We also present that L. fermentum ME-3 can transport GSH from environment and synthesize GSH. This means that it is characterized by a complete glutathione system: synthesis, uptake and redox turnover ability that makes L. fermentum ME-3 a perfect protector against oxidative stress. To our best knowledge studies on existence of the complete glutathione system in probiotic LAB strains are still absent and glutathione synthesis in them has not been demonstrated.