1.
Abu Hamdeh, Sami, et al.
(författare)
Differential DNA methylation of the genes for amyloid precursor protein, tau, and neurofilaments in human traumatic brain injury
2021
Ingår i: Journal of Neurotrauma. - : Mary Ann Liebert Inc. - 0897-7151 .- 1557-9042. ; 38:12, s. 1662-1669
Tidskriftsartikel (refereegranskat) abstract
Traumatic brain injury (TBI) is an established risk factor for neurodegenerative disorders and dementias. Epigenetic modifications, such as DNA methylation, may alter the expression of genes without altering the DNA sequence in response to environmental factors. We hypothesized that DNA methylation changes may occur in the injured human brain and be implicated in the neurodegenerative aftermath of TBI. The DNA methylation status of genes related to neurodegeneration; for example, amyloid beta precursor protein (APP), microtubule associated protein tau (MAPT), neurofilament heavy (NEFH), neurofilament medium (NEFM), and neurofilament light (NEFL), was analyzed in fresh, surgically resected human brain tissue from 17 severe TBI patients and compared with brain biopsy samples from 19 patients with idiopathic normal pressure hydrocephalus (iNPH). We also performed an epigenome-wide association study (EWAS) comparing TBI patients with iNPH controls. Thirty-eight CpG sites in the APP, MAPT, NEFH, and NEFL genes were differentially methylated by TBI. Among the top 20 differentially methylated CpG sites, 11 were in the APP gene. In addition, the EWAS evaluating 828,888 CpG sites revealed 308 differentially methylated CpG sites in genes related to cellular/anatomical structure development, cell differentiation, and anatomical morphogenesis. These preliminary findings provide the first evidence of an altered DNA methylome in the injured human brain, and may have implications for the neurodegenerative disorders associated with TBI.
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Ahmed, Aisha S., et al.
(författare)
Attenuation of Pain and Inflammation in Adjuvant-Induced Arthritis by the Proteasome Inhibitor MG132
2010
Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 62:7, s. 2160-2169
Tidskriftsartikel (refereegranskat) abstract
Objective. In rheumatoid arthritis (RA), pain and joint destruction are initiated and propagated by the production of proinflammatory mediators. Synthesis of these mediators is regulated by the transcription factor NF-kappa B, which is controlled by the ubiquitin proteasome system (UPS). The present study explored the effects of the proteasome inhibitor MG132 on inflammation, pain, joint destruction, and expression of sensory neuropeptides as markers of neuronal response in a rat model of arthritis. Methods. Arthritis was induced in rats by injection of heat-killed Mycobacterium butyricum. Arthritis severity was scored, and nociception was evaluated by mechanical pressure applied to the hind paw. Joint destruction was assessed by radiologic and histologic analyses. NF-kappa B DNA-binding activity was analyzed by electromobility shift assay, and changes in the expression of the p50 NF-kappa B subunit and the proinflammatory neuropeptides substance P (SP) and calcitonin generelated peptide (CGRP) were detected by immunohistochemistry. Results. Arthritic rats treated with MG132 demonstrated a marked reduction in inflammation, pain, and joint destruction. The elevated DNA-binding activity of the NF-kappa B/p50 homodimer and p50, as well as the neuronal expression of SP and CGRP, observed in the ankle joints of arthritic rats were normalized after treatment with MG132. Conclusion. In arthritic rats, inhibition of proteasome reduced the severity of arthritis and reversed the pain behavior associated with joint inflammation. These effects may be mediated through the inhibition of NF-kappa B activation and may possibly involve the peripheral nervous system. New generations of nontoxic proteasome inhibitors may represent a novel pharmacotherapy for RA.
4.
Bivehed, Erik, et al.
(författare)
Region-specific bioconversion of dynorphin neuropeptide detected by in situ histochemistry and MALDI imaging mass spectrometry
2017
Ingår i: Peptides. - : Elsevier BV. - 0196-9781 .- 1873-5169. ; 87, s. 20-27
Tidskriftsartikel (refereegranskat) abstract
Brain region-specific expression of proteolytic enzymes can control the biological activity of endogenous neuropeptides and has recently been targeted for the development of novel drugs, for neuropathic pain, cancer, and Parkinson's disease. Rapid and sensitive analytical methods to profile modulators of enzymatic activity are important for finding effective inhibitors with high therapeutic value. Combination of in situ enzyme histochemistry with MALDI imaging mass spectrometry allowed developing a highly sensitive method for analysis of brain-area specific neuropeptide conversion of synthetic and endogenous neuropeptides, and for selection of peptidase inhibitors that differentially target conversion enzymes at specific anatomical sites. Conversion and degradation products of Dynorphin B as model neuropeptide and effects of peptidase inhibitors applied to native brain tissue sections were analyzed at different brain locations. Synthetic dynorphin B (2 pmol) was found to be converted to the N-terminal fragments on brain sections whereas fewer C-terminal fragments were detected. N-ethylmaleimide (NEM), a non-selective inhibitor of cysteine peptidases, almost completely blocked the conversion of dynorphin B to dynorphin B(1-6; Leu-Enk-Arg), (1-9), (2-13), and (7-13). Proteinase inhibitor cocktail, and also incubation with acetic acid displayed similar results. Bioconversion of synthetic dynorphin B was region-specific producing dynorphin B(1-7) in the cortex and dynorphin B (2-13) in the striatum. Enzyme inhibitors showed region-and enzyme-specific inhibition of dynorphin bioconversion. Both phosphoramidon (inhibitor of the known dynorphin converting enzyme neprilysin) and opiorphin (inhibitor of neprilysin and aminopeptidase N) blocked cortical bioconversion to dynorphin B(1-7), wheras only opiorphin blocked striatal bioconversion to dynorphin B(2-13). This method may impact the development of novel therapies with aim to strengthen the effects of endogenous neuropeptides under pathological conditions such as chronic pain. Combining histochemistry and MALDI imaging MS is a powerful and sensitive tool for the study of inhibition of enzyme activity directly in native tissue sections. (C) 2016 The Authors. Published by Elsevier Inc.
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Chizhmakov, Igor, et al.
(författare)
Molecular mechanism for opioid dichotomy : bidirectional effect of mu-opioid receptors on P2X(3) receptor currents in rat sensory neurones
2015
Ingår i: Purinergic Signalling Purinergic Signalling. - : Springer Science and Business Media LLC. - 1573-9538 .- 1573-9546. ; 11:2, s. 171-181
Tidskriftsartikel (refereegranskat) abstract
Here, we describe a molecular switch associated with opioid receptors-linked signalling cascades that provides a dual opioid control over P2X(3) purinoceptor in sensory neurones. Leu-enkephalin inhibited P2X(3)-mediated currents with IC50 similar to 10 nM in similar to 25 % of small nociceptive rat dorsal root ganglion (DRG) neurones. In contrast, in neurones pretreated with pertussis toxin leu-enkephalin produced stable and significant increase of P2X(3) currents. All effects of opioid were abolished by selective mu-opioid receptor antagonist D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP), nonselective inhibitor naloxone, and by PLC inhibitor U73122. Thus, we discovered a dual link between purinoceptors and mu-opioid receptors: the latter exert both inhibitory (pertussis toxin-sensitive) and stimulatory (pertussis toxin-insensitive) actions on P2X(3) receptors through phospholipase C (PLC)-dependent pathways. This dual opioid control of P2X(3) receptors may provide a molecular explanation for dichotomy of opioid therapy. Pharmacological control of this newly identified facilitation/inhibition switch may open new perspectives for the adequate medical use of opioids, the most powerful pain-killing agents known today.
8.
El-Hage, Nazira, et al.
(författare)
Morphine exacerbates HIV-1 Tat-induced cytokine production in astrocytes through convergent effects on [Ca(2+)](i), NF-kappaB trafficking and transcription
2008
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3:12, s. e4093-
Tidskriftsartikel (refereegranskat) abstract
Astroglia are key cellular sites where opiate drug signals converge with the proinflammatory effects of HIV-1 Tat signals to exacerbate HIV encephalitis. Despite this understanding, the molecular sites of convergence driving opiate-accelerated neuropathogenesis have not been deciphered. We therefore explored potential points of interaction between the signaling pathways initiated by HIV-1 Tat and opioids in striatal astrocytes. Profiling studies screening 152 transcription factors indicated that the nuclear factor-kappa B (NF-kappaB) subunit, c-Rel, was a likely candidate for Tat or Tat plus opiate-induced increases in cytokine and chemokine production by astrocytes. Pretreatment with the NF-kappaB inhibitor parthenolide provided evidence that Tat+/-morphine-induced release of MCP-1, IL-6 and TNF-alpha by astrocytes is NF-kappaB dependent. The nuclear export inhibitor, leptomycin B, blocked the nucleocytoplasmic shuttling of NF-kappaB; causing p65 (RelA) accumulation in the nucleus, and significantly attenuated cytokine production in Tat+/-morphine exposed astrocytes. Similarly, chelating intracellular calcium ([Ca(2+)](i)) blocked Tat+/-morphine-evoked MCP-1 and IL-6 release, while artificially increasing the concentration of extracellular Ca(2+) reversed this effect. Taken together, these results demonstrate that: 1) exposure to Tat+/-morphine is sufficient to activate NF-kappaB and cytokine production, 2) the release of MCP-1 and IL-6 by Tat+/-morphine are highly Ca(2+)-dependent, while TNF-alpha appears to be less affected by the changes in [Ca(2+)](i), and 3) in the presence of Tat, exposure to opiates augments Tat-induced NF-kappaB activation and cytokine release through a Ca(2+)-dependent pathway.
9.
Henriksson, Richard, et al.
(författare)
Elevated synaptophysin I in the prefrontal cortex of human chronic alcoholics
2008
Ingår i: Synapse. - : Wiley. - 0887-4476 .- 1098-2396. ; 62:11, s. 829-33
Tidskriftsartikel (refereegranskat) abstract
Convergent lines of evidence suggest potentiation of glutamatergic synapses after chronic ethanol exposure, and indicate that the presynaptic effect hereof is on modulators of synaptic strength rather than on executors of glutamate release. To address this hypothesis in the context of ethanol dependence in humans, we used semiquantitative immunoblotting to compare the immunoreactivities of synaptophysin I, syntaxin 1A, synaptosome-associated protein 25, and vesicle-associated membrane protein in the prefrontal and motor cortices between chronic alcoholics and control subjects. We found a region-specific elevation in synaptophysin I immunoreactivity in the prefrontal cortex of alcoholics, but detected no significant differences between the groups in the immunoreactivities of the other three proteins. Our findings are consistent with an effect of repeated ethanol exposure on modulators of synaptic strength but not on executors of glutamate release, and suggest a role for synaptophysin I in the enduring neuroplasticity in the prefrontal cortical glutamate circuitry that is associated with ethanol dependence.
10.
Hugonin, Loïc, et al.
(författare)
Calcium influx into phospholipid vesicles caused by dynorphin neuropeptides
2008
Ingår i: Biochimica et Biophysica Acta - Biomembranes. - : Elsevier BV. - 0005-2736 .- 1879-2642 .- 0006-3002. ; 1778:5, s. 1267-1273
Tidskriftsartikel (refereegranskat) abstract
Dynorphins, endogeneous opioid peptides, function as ligands to the opioid kappa receptors but also induce non-opioid excitotoxic effects. Dynorphin A can increase the intra-neuronal calcium concentration through a non-opioid and non-NMDA mechanism. In this investigation, we show that big dynorphin, dynorphin A and to some extent dynorphin A (1-13), but not dynorphin B, allow calcium to enter into large unilamellar phospholipid vesicles with partly negative headgroups. The effects parallel the previously studied potency of dynorphins to translocate through biological membranes and to cause calcein leakage from large unilamellar phospholipid vesicles. There is no calcium ion influx into vesicles with zwitterionic headgroups. We have also investigated if the dynorphins can translocate through the vesicle membranes and estimated the relative strength of interaction of the peptides with the vesicles by fluorescence resonance energy transfer. The results show that dynorphins do not translocate in this membrane model system. There is a strong electrostatic contribution to the interaction of the peptides with the membrane model system.
