| 1. |
- Abu Hamdeh, Sami, et al.
(author)
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Differential DNA methylation of the genes for amyloid precursor protein, tau, and neurofilaments in human traumatic brain injury
- 2021
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In: Journal of Neurotrauma. - : Mary Ann Liebert Inc. - 0897-7151 .- 1557-9042. ; 38:12, s. 1662-1669
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Journal article (peer-reviewed)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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| 2. |
- Adjan, V. V., et al.
(author)
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Caspase-3 activity is reduced after spinal cord injury in mice lacking dynorphin : differential effects on glia and neurons
- 2007
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In: Neuroscience. - : Elsevier BV. - 0306-4522 .- 1873-7544. ; 148:3, s. 724-36
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Journal article (peer-reviewed)abstract
- Dynorphins are endogenous opioid peptide products of the prodynorphin gene. An extensive literature suggests that dynorphins have deleterious effects on CNS injury outcome. We thus examined whether a deficiency of dynorphin would protect against tissue damage after spinal cord injury (SCI), and if individual cell types would be specifically affected. Wild-type and prodynorphin(-/-) mice received a moderate contusion injury at 10th thoracic vertebrae (T10). Caspase-3 activity at the injury site was significantly decreased in tissue homogenates from prodynorphin(-/-) mice after 4 h. We examined frozen sections at 4 h post-injury by immunostaining for active caspase-3. At 3-4 mm rostral or caudal to the injury, >90% of all neurons, astrocytes and oligodendrocytes expressed active caspase-3 in both wild-type and knockout mice. At 6-7 mm, there were fewer caspase-3(+) oligodendrocytes and astrocytes than at 3-4 mm. Importantly, caspase-3 activation was significantly lower in prodynorphin(-/-) oligodendrocytes and astrocytes, as compared with wild-type mice. In contrast, while caspase-3 expression in neurons also declined with further distance from the injury, there was no effect of genotype. Radioimmunoassay showed that dynorphin A(1-17) was regionally increased in wild-type injured versus sham-injured tissues, although levels of the prodynorphin processing product Arg(6)-Leu-enkephalin were unchanged. Our results indicate that dynorphin peptides affect the extent of post-injury caspase-3 activation, and that glia are especially sensitive to these effects. By promoting caspase-3 activation, dynorphin peptides likely increase the probability of glial apoptosis after SCI. While normally beneficial, our findings suggest that prodynorphin or its peptide products become maladaptive following SCI and contribute to secondary injury.
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| 3. |
- Ahmed, Aisha S., et al.
(author)
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Activation of NF-kappa B in Synovium versus Cartilage from Patients with Advanced Knee Osteoarthritis : A Potential Contributor to Inflammatory Aspects of Disease Progression
- 2018
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In: Journal of Immunology. - : AMER ASSOC IMMUNOLOGISTS. - 0022-1767 .- 1550-6606. ; 201:7, s. 1918-1927
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Journal article (peer-reviewed)abstract
- The aim was to assess the activation and association of the NF-kappa B system across synovial membrane (SM) and articular cartilage (AC) in patients with knee osteoarthritis (OA) and ascertain its potential effects on catabolic mediator expression in advanced OA. SM and AC were obtained from 40 OA patients undergoing total knee arthroplasty and from 19 postmortem control subjects. NF-kappa B subunit RelA in nuclear and cytosolic fractions and NF-kappa B1-DNA binding in nuclear extracts was assessed by ELISA, whereas NFKB1, RELA, IL-8, IL-6, and MMP3 gene expression were analyzed by reverse transcriptase-quantitative PCR in tissues. We observed higher SM nuclear RelA protein levels and upregulated NF-kappa B1-DNA binding in OA patients compared with postmortem controls. However, in AC, lower nuclear RelA levels were observed compared with cytosolic extracts in patients. Nuclear RelA levels correlated positively with NF-kappa B1-DNA binding in SM and AC in patients. SM RELA and MMP3 mRNA levels were upregulated, whereas IL-8 and IL-6 as well as AC RELA were downregulated in patients compared with controls. In SM, nuclear RelA levels correlated positively with MMP3 gene expression in patients. A negative correlation was observed between SM nuclear RelA levels and AC NF-kappa B1-DNA binding, and SM nuclear NF-kappa B1-DNA binding correlated negatively with AC MMP3 and NFKB1 mRNA levels in patients. These findings highlight NF-kappa B-triggered cross-talk and feedback mechanisms between SM and AC in OA. Further, our findings strongly support a role for an activated NF-kappa B system in the transcriptional mechanism of inflammatory processes, especially in SM of patients with advanced OA.
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| 4. |
- Ahmed, Aisha S., et al.
(author)
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Attenuation of Pain and Inflammation in Adjuvant-Induced Arthritis by the Proteasome Inhibitor MG132
- 2010
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In: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 62:7, s. 2160-2169
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Journal article (peer-reviewed)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.
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| 5. |
- Ahmed, Aisha Siddiqah, et al.
(author)
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Proteasome inhibitor MG132 modulates inflammatory pain by central mechanisms in adjuvant arthritis.
- 2017
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In: International journal of rheumatic diseases. - 1756-185X. ; 20:1, s. 25-32
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Journal article (peer-reviewed)abstract
- AIMS: In rheumatoid arthritis (RA), pain and inflammation are initial symptoms followed by various degrees of bone and cartilage destruction. Previously, we have shown that reversible proteasome inhibitor MG132 attenuates pain and joint inflammation in a rat model of adjuvant-arthritis. Our present study aims to study the effects of MG132 on molecular changes in the dorsal root ganglia (DRG) and in the spinal cord (SC) using the same animal model.METHODS: Arthritis was induced by heat-killed Mycobacterium butyricum in rats. The expression of substance P (SP) was analyzed by quantitative reverse transcription polymerase chain reaction and immunohistochemistry in DRG and in the SC. The nuclear factor-κB (NF-κB) DNA-binding activity in the SC was analyzed by electromobility shift assay.RESULTS: Arthritic rats treated daily with MG132 demonstrated a marked reduction of SP gene expression in the DRG and number of SP-positive cells was reduced. In the spinal cord of arthritic rats elevated SP messenger RNA levels were normalized and NF-κB-DNA-binding activity was down-regulated in arthritic rats treated with MG132.CONCLUSION: Our results indicate that proteasome inhibitor MG132 attenuates pain in adjuvant arthritis by targeting the sensory neuropeptide substance P in the peripheral and central nervous systems. These effects may be mediated through the inhibition of NF-κB activation.
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| 6. |
- Ahmed, Aisha S, et al.
(author)
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Suppression of pain and joint destruction by inhibition of the proteasome system in experimental osteoarthritis
- 2012
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In: Pain. - : Ovid Technologies (Wolters Kluwer Health). - 0304-3959 .- 1872-6623. ; 153:1, s. 18-26
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Journal article (peer-reviewed)abstract
- Osteoarthritis is a degenerative joint disease with pain and loss of joint function as major pathological features. Recent studies show that proteasome inhibitors reduce pain in various pathological conditions. We evaluated the effects of MG132, a reversible proteasome inhibitor on pain and joint destruction in a rat model of osteoarthritis. Osteoarthritis was induced by intraarticular injection of monosodium iodoacetate into the rat knee. Knee joint stiffness was scored and nociception was evaluated by mechanical pressure applied to the respective hind paw. Knee joint destruction was assessed by radiological and histological analyses. Expression of matrix metalloproteinase-3 (MMP-3) was analyzed by quantitative reverse transcription polymerase chain reaction in the knee articular cartilage. Expression of substance P (SP) and calcitonin gene-related peptide (CGRP) was studied in the dorsal root ganglia (L4–L6) by quantitative reverse transcription polymerase chain reaction and in the knee joints by immunohistochemistry. Our results indicate that daily treatment of osteoarthritic rats with MG132 significantly increases their mobility while the swelling, pain thresholds, and pathological features of the affected joints were reduced. Furthermore, the upregulated expression of MMP-3, SP, and CGRP in the arthritic rats was normalized by MG132 administration. We conclude that the proteasome inhibitor MG132 reduces pain and joint destruction, probably by involving the peripheral nervous system, and that changes in SP and CGRP expression correlate with alterations in behavioural responses. Our findings suggest that nontoxic proteasome inhibitors may represent a novel pharmacotherapy for osteoarthritis.
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| 7. |
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| 8. |
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| 9. |
- Bakalkin, Georgy, et al.
(author)
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Coordinated expression of the renin-angiotensin genes in the lumbar spinal cord : Lateralization and effects of unilateral brain injury
- 2021
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In: European Journal of Neuroscience. - : John Wiley & Sons. - 0953-816X .- 1460-9568. ; 54:4, s. 5560-5573
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Journal article (peer-reviewed)abstract
- In spite of its apparent symmetry, the spinal cord is asymmetric in its reflexes and gene expression patterns including leftward expression bias of the opioid and glutamate genes. To examine whether this is a general phenomenon for neurotransmitter and neurohormonal genes, we here characterized expression and co-expression (transcriptionally coordinated) patterns of genes of the renin-angiotensin system (RAS) that is involved in neuroprotection and pathological neuroplasticity in the left and right lumbar spinal cord. We also tested whether the RAS expression patterns were affected by unilateral brain injury (UBI) that rewired lumbar spinal neurocircuits. The left and right halves of the lumbar spinal cord were analysed in intact rats, and rats with left- or right-sided unilateral cortical injury, and left- or right-sided sham surgery. The findings were (i) lateralized expression of the RAS genes Ace, Agtr2 and Ren with higher levels on the left side; (ii) the asymmetry in coordination of the RAS gene expression that was stronger on the right side; (iii) the decay in coordination of co-expression of the RAS and neuroplasticity-related genes induced by the right-side but not left-side sham surgery and UBI; and (iv) the UBI-induced shift to negative regulatory interactions between RAS and neuroplasticity-related genes on the contralesional spinal side. Thus, the RAS genes may be a part of lateralized gene co-expression networks and have a role in a side-specific regulation of spinal neurocircuits.
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| 10. |
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| 11. |
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| 12. |
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| 13. |
- Bakalkin, Georgy, et al.
(author)
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Prodynorphin mutations cause the neurodegenerative disorder spinocerebellar ataxia type 23.
- 2010
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In: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 87:5, s. 593-603
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Journal article (peer-reviewed)abstract
- Spinocerebellar ataxias (SCAs) are dominantly inherited neurodegenerative disorders characterized by progressive cerebellar ataxia and dysarthria. We have identified missense mutations in prodynorphin (PDYN) that cause SCA23 in four Dutch families displaying progressive gait and limb ataxia. PDYN is the precursor protein for the opioid neuropeptides, α-neoendorphin, and dynorphins A and B (Dyn A and B). Dynorphins regulate pain processing and modulate the rewarding effects of addictive substances. Three mutations were located in Dyn A, a peptide with both opioid activities and nonopioid neurodegenerative actions. Two of these mutations resulted in excessive generation of Dyn A in a cellular model system. In addition, two of the mutant Dyn A peptides induced toxicity above that of wild-type Dyn A in cultured striatal neurons. The fourth mutation was located in the nonopioid PDYN domain and was associated with altered expression of components of the opioid and glutamate system, as evident from analysis of SCA23 autopsy tissue. Thus, alterations in Dyn A activities and/or impairment of secretory pathways by mutant PDYN may lead to glutamate neurotoxicity, which underlies Purkinje cell degeneration and ataxia. PDYN mutations are identified in a small subset of ataxia families, indicating that SCA23 is an infrequent SCA type (~0.5%) in the Netherlands and suggesting further genetic SCA heterogeneity.
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| 14. |
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| 15. |
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| 16. |
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| 17. |
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| 18. |
- Bakalkin, Georgy
(author)
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The left-right side-specific endocrine signaling in the effects of brain lesions : questioning of the neurological dogma
- 2022
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In: Cellular and Molecular Life Sciences (CMLS). - : Springer Nature. - 1420-682X .- 1420-9071. ; 79
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Research review (peer-reviewed)abstract
- Each cerebral hemisphere is functionally connected to the contralateral side of the body through the decussating neural tracts. The crossed neural pathways set a basis for contralateral effects of brain injury such hemiparesis and hemiplegia as it has been already noted by Hippocrates. Recent studies demonstrated that, in addition to neural mechanisms, the contralateral effects of brain lesions are mediated through the humoral pathway by neurohormones that produce either the left or right side-specific effects. The side-specific humoral signaling defines whether the left or right limbs are affected after a unilateral brain injury. The hormonal signals are released by the pituitary gland and may operate through their receptors that are lateralized in the spinal cord and involved in the side-specific control of symmetric neurocircuits innervating the left and right limbs. Identification of features and a proportion of neurological deficits transmitted by neurohormonal signals vs. those mediated by neural pathways is essential for better understanding of mechanisms of brain trauma and stroke and development of new therapies. In a biological context, the left-right side-specific neuroendocrine signaling may be fundamental for the control of the left- and right-sided processes in bilaterally symmetric animals.
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| 19. |
- Bakalkin, Georgy, et al.
(author)
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Unilateral traumatic brain injury of the left and right hemisphere produces the left hindlimb response in rats
- 2021
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In: Experimental Brain Research. - : Springer Science and Business Media LLC. - 0014-4819 .- 1432-1106. ; 239:7, s. 2221-2232
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Journal article (peer-reviewed)abstract
- Traumatic brain injury and stroke result in hemiplegia, hemiparesis, and asymmetry in posture. The effects are mostly contralateral; however, ipsilesional deficits may also develop. We here examined whether ablation brain injury and controlled cortical impact (CCI), a rat model of clinical focal traumatic brain injury, both centered over the left or right sensorimotor cortex, induced hindlimb postural asymmetry (HL-PA) with contralesional or ipsilesional limb flexion. The contralesional hindlimb was flexed after left or right side ablation injury. In contrast, both the left and right CCI unexpectedly produced HL-PA with flexion on left side. The flexion persisted after complete spinal cord transection suggesting that CCI triggered neuroplastic processes in lumbar neural circuits enabling asymmetric muscle contraction. Left limb flexion was exhibited under pentobarbital anesthesia. However, under ketamine anesthesia, the body of the left and right CCI rats bent laterally in the coronal plane to the ipsilesional side suggesting that the left and right injury engaged mirror-symmetrical motor pathways. Thus, the effects of the left and right CCI on HL-PA were not mirror-symmetrical in contrast to those of the ablation brain injury, and to the left and right CCI produced body bending. Ipsilateral effects of the left CCI on HL-PA may be mediated by a lateralized motor pathway that is not affected by the left ablation injury. Alternatively, the left-side-specific neurohormonal mechanism that signals from injured brain to spinal cord may be activated by both the left and right CCI but not by ablation injury.
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| 20. |
- Bazov, Igor, 1973-, et al.
(author)
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Downregulation of the neuronal opioid gene expression concomitantly with neuronal decline in dorsolateral prefrontal cortex of human alcoholics
- 2018
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In: Translational Psychiatry. - : NATURE PUBLISHING GROUP. - 2158-3188. ; 8
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Journal article (peer-reviewed)abstract
- Molecular changes in cortical areas of addicted brain may underlie cognitive impairment and loss of control over intake of addictive substances and alcohol. Prodynorphin (PDYN) gives rise to dynorphin (DYNs) opioid peptides which target kappa-opioid receptor (KOR). DYNs mediate alcohol-induced impairment of learning and memory, while KOR antagonists block excessive, compulsive-like drug and alcohol self-administration in animal models. In human brain, the DYN/KOR system may undergo adaptive changes, which along with neuronal loss, may contribute to alcohol-associated cognitive deficit. We addressed this hypothesis by comparing the expression levels and co-expression (transcriptionally coordinated) patterns of PDYN and KOR (OPRK1) genes in dorsolateral prefrontal cortex (dlPFC) between human alcoholics and controls. Postmortem brain specimens of 53 alcoholics and 55 controls were analyzed. PDYN was found to be downregulated in dlPFC of alcoholics, while OPRK1 transcription was not altered. PDYN downregulation was confined to subgroup of subjects carrying C, a high-risk allele of PDYN promoter SNP rs1997794 associated with alcoholism. Changes in PDYN expression did not depend on the decline in neuronal proportion in alcoholics, and thereby may be attributed to transcriptional adaptations in alcoholic brain. Absolute expression levels of PDYN were lower compared to those of OPRK1, suggesting that PDYN expression is a limiting factor in the DYN/KOR signaling, and that the PDYN downregulation diminishes efficacy of DYN/KOR signaling in dlPFC of human alcoholics. The overall outcome of the DYN/KOR downregulation may be disinhibition of neurotransmission, which when overactivated could contribute to formation of alcohol-related behavior.
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| 21. |
- Bazov, Igor, 1973-, et al.
(author)
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Dynorphin and κ-Opioid Receptor Dysregulation in the Dopaminergic Reward System of Human Alcoholics.
- 2018
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In: Molecular Neurobiology. - : Springer. - 0893-7648 .- 1559-1182. ; 55:8, s. 7049-7061
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Journal article (peer-reviewed)abstract
- Molecular changes induced by excessive alcohol consumption may underlie formation of dysphoric state during acute and protracted alcohol withdrawal which leads to craving and relapse. A main molecular addiction hypothesis is that the upregulation of the dynorphin (DYN)/κ-opioid receptor (KOR) system in the nucleus accumbens (NAc) of alcohol-dependent individuals causes the imbalance in activity of D1- and D2 dopamine receptor (DR) expressing neural circuits that results in dysphoria. We here analyzed post-mortem NAc samples of human alcoholics to assess changes in prodynorphin (PDYN) and KOR (OPRK1) gene expression and co-expression (transcriptionally coordinated) patterns. To address alterations in D1- and D2-receptor circuits, we studied the regulatory interactions between these pathways and the DYN/KOR system. No significant differences in PDYN and OPRK1 gene expression levels between alcoholics and controls were evident. However, PDYN and OPRK1 showed transcriptionally coordinated pattern that was significantly different between alcoholics and controls. A downregulation of DRD1 but not DRD2 expression was seen in alcoholics. Expression of DRD1 and DRD2 strongly correlated with that of PDYN and OPRK1 suggesting high levels of transcriptional coordination between these gene clusters. The differences in expression and co-expression patterns were not due to the decline in neuronal proportion in alcoholic brain and thereby represent transcriptional phenomena. Dysregulation of DYN/KOR system and dopamine signaling through both alterations in co-expression patterns of opioid genes and decreased DRD1 gene expression may contribute to imbalance in the activity of D1- and D2-containing pathways which may lead to the negative affective state in human alcoholics.
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| 22. |
- Bazov, Igor
(author)
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Epigenetic Dysregulations in the Brain of Human Alcoholics : Analysis of Opioid Genes
- 2016
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Doctoral thesis (other academic/artistic)abstract
- Neuropeptides are special in their expression profiles restricted to neuronal subpopulations and low tissue mRNA levels. Genetic, epigenetic and transcriptional mechanisms that define spatiotemporal expression of the neuropeptide genes have utmost importance for the formation and functions of neural circuits in normal and pathological human brain. This thesis focuses on regulation of transcription of the opioid/nociceptin genes, the largest neuropeptide family, and on identification of adaptive changes in these mechanisms associated with alcoholism as model human pathology. Two epigenetic mechanisms, the common for most cells in the dorsolateral prefrontal cortex (dlPFC) and the neuron-subpopulation specific that may orchestrate prodynorphin (PDYN) transcription in the human dlPFC have been uncovered. The first, repressive mechanism may operate through control of DNA methylation/demethylation in a short, nucleosome size promoter CpG island (CGI). The second mechanism may involve USF2, the sequence–specific methylation–sensitive transcription factor which interaction with its target element in the CpG island results in USF2 and PDYN co-expression in the same neurons. The short PDYN promoter CGI may function as a chromatin element that integrates cellular and environmental signals through changes in methylation and transcription factor binding. Alterations in USF2–dependent PDYN transcription are affected by the promoter SNP (rs1997794: T>C) under transition to pathological state, i.e. in the alcoholic brain. This and two other PDYN SNPs that are most significantly associated with alcoholism represent CpG-SNPs, which are differentially methylated in the human dlPFC. The T, low risk allele of the promoter SNP forms a noncanonical AP-1–binding element. JUND and FOSB proteins, which may form homo- or heterodimers have been identified as dominant constituents of AP-1 complex. The C, non-risk variant of the PDYN 3′ UTR SNP (rs2235749 SNP: C>T) demonstrated significantly higher methylation in alcoholics compared to controls. PDYN mRNA and dynorphin levels significantly and positively correlated with methylation of the PDYN 3′ UTR CpG-SNP suggesting its involvement in PDYN regulation. A DNA–binding factor with differential binding affinity for the T allele and methylated and unmethylated C alleles of the PDYN 3′ UTR SNP (the T allele specific binding factor, Ta-BF) has been discovered, which may function as a regulator of PDYN transcription. These findings emphasize the complexity of PDYN regulation that determines its expression in specific neuronal subpopulations and suggest previously unknown integration of epigenetic, transcriptional and genetic mechanisms that orchestrate alcohol–induced molecular adaptations in the human brain. Given the important role of PDYN in addictive behavior, the findings provide a new insight into fundamental molecular mechanisms of human brain disorder. In addition to PDYN in the dlPFC, the PNOC gene in the hippocampus and OPRL1 gene in central amygdala that were downregulated in alcoholics may contribute to impairment of cognitive control over alcohol seeking and taking behaviour.
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| 23. |
- Bazov, Igor, 1973-, et al.
(author)
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Neuronal Expression of Opioid Gene is Controlled by Dual Epigenetic and Transcriptional Mechanism in Human Brain
- 2018
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In: Cerebral Cortex. - : Oxford University Press (OUP). - 1047-3211 .- 1460-2199. ; 28:9, s. 3129-3142
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Journal article (peer-reviewed)abstract
- Molecular mechanisms that define patterns of neuropeptide expression are essential for the formation and rewiring of neural circuits. The prodynorphin gene (PDYN) gives rise to dynorphin opioid peptides mediating depression and substance dependence. We here demonstrated that PDYN is expressed in neurons in human dorsolateral prefrontal cortex (dlPFC), and identified neuronal differentially methylated region in PDYN locus framed by CCCTC-binding factor binding sites. A short, nucleosome size human-specific promoter CpG island (CGI), a core of this region may serve as a regulatory module, which is hypomethylated in neurons, enriched in 5-hydroxymethylcytosine, and targeted by USF2, a methylation-sensitive E-box transcription factor (TF). USF2 activates PDYN transcription in model systems, and binds to nonmethylated CGI in dlPFC. USF2 and PDYN expression is correlated, and USF2 and PDYN proteins are co-localized in dlPFC. Segregation of activatory TF and repressive CGI methylation may ensure contrasting PDYN expression in neurons and glia in human brain.
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| 24. |
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| 25. |
- Bazov, Igor, 1973-, et al.
(author)
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Prodynorphin Epialleles
- 2016
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In: Epigenetics and Neuroendocrinology. - Cham : Springer. - 9783319299006 - 9783319299013 ; , s. 43-76
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Book chapter (peer-reviewed)abstract
- Dynorphins, the endogenous ligands for kappa-opioid receptors play an essential role in neuroendocrine regulation, stress response, reward processing, and mood control. These neuropeptides induce strong dysphoric and aversive effects. Polymorphisms in the prodynorphin (PDYN), the dynorphin-encoding gene, are associated with substance addiction and negative craving, while dynorphin mutations cause neurodegeneration in the human brain. Similarly to other neuropeptide genes, PDYN is expressed in selective neural circuits at extremely low tissue levels. A sophisticated epigenetic/transcriptional regulation by cell lineage-specific transcription factors (TFs), insulators, and silencers such as CCCTC-binding factor (CTCF) and RE1-silencing transcription factor (REST) along with mechanisms that control neuronal activity-dependent transcription may define spatial, temporal, and adaptive PDYN expression patterns. Impairment of the epigenetic control of PDYN expression may contribute to human pathological conditions including substance dependence, depression, and chronic pain. Epigenetic and environmental factors may mechanistically converge on the PDYN CpG-SNPs associated with a risk for alcohol dependence, and the resulting methylation signals may be translated into disease predisposition via alterations in PDYN transcription. Understanding the mechanisms that regulate neuropeptide epigenome and transcriptome is essential for understanding of neuropeptide-mediated functional connectivity within neural circuits which activities define cognition and behavior.
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