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Stankiewicz AM, Goscik J, Dyr W, Juszczak GR, Ryglewicz D, Swiergiel AH, Wieczorek M, Stefanski R. Novel candidate genes for alcoholism--transcriptomic analysis of prefrontal medial cortex, hippocampus and nucleus accumbens of Warsaw alcohol-preferring and non-preferring rats. Pharmacol Biochem Behav 2015; 139:27-38. [PMID: 26455281 DOI: 10.1016/j.pbb.2015.10.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 10/06/2015] [Accepted: 10/06/2015] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Animal models provide opportunity to study neurobiological aspects of human alcoholism. Changes in gene expression have been implicated in mediating brain functions, including reward system and addiction. The current study aimed to identify genes that may underlie differential ethanol preference in Warsaw High Preferring (WHP) and Warsaw Low Preferring (WLP) rats. METHODS Microarray analysis comparing gene expression in nucleus accumbens (NAc), hippocampus (HP) and medial prefrontal cortex (mPFC) was performed in male WHP and WLP rats bred for differences in ethanol preference. RESULTS Differential and stable between biological repeats expression of 345, 254 and 129 transcripts in NAc, HP and mPFC was detected. Identified genes and processes included known mediators of ethanol response (Mx2, Fam111a, Itpr1, Gabra4, Agtr1a, LTP/LTD, renin-angiotensin signaling pathway), toxicity (Sult1c2a, Ces1, inflammatory response), as well as genes involved in regulation of important addiction-related brain systems such as dopamine, tachykinin or acetylcholine (Gng7, Tac4, Slc5a7). CONCLUSIONS The identified candidate genes may underlie differential ethanol preference in an animal model of alcoholism. COMMENT Names of genes are written in italics, while names of proteins are written in standard font. Names of human genes/proteins are written in all capital letters. Names of rodent genes/proteins are written in capital letter followed by small letters.
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Affiliation(s)
- Adrian M Stankiewicz
- Department of Animal Behaviour, Institute of Genetics and Animal Breeding, Polish Academy of Sciences, 05-552 Jastrzebiec, Poland
| | - Joanna Goscik
- Software Department, Faculty of Computer Science, Bialystok University of Technology, 15-351 Bialystok, Poland
| | - Wanda Dyr
- Department of Pharmacology and Physiology of the Nervous System, Institute of Psychiatry and Neurology, 02-957 Warsaw, Poland
| | - Grzegorz R Juszczak
- Department of Animal Behaviour, Institute of Genetics and Animal Breeding, Polish Academy of Sciences, 05-552 Jastrzebiec, Poland
| | - Danuta Ryglewicz
- First Department of Neurology, Institute of Psychiatry and Neurology, 02-957 Warsaw, Poland
| | - Artur H Swiergiel
- Department of Animal and Human Physiology, Faculty of Biology, University of Gdansk, 80-308 Gdansk, Poland; Department of Pharmacology, Toxicology and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA71130, USA.
| | - Marek Wieczorek
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lodz, Poland
| | - Roman Stefanski
- Department of Pharmacology and Physiology of the Nervous System, Institute of Psychiatry and Neurology, 02-957 Warsaw, Poland
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102
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Kozaki Y, Umetsu R, Mizukami Y, Yamamura A, Kitamori K, Tsuchikura S, Ikeda K, Yamori Y. Peripheral gene expression profile of mechanical hyperalgesia induced by repeated cold stress in SHRSP5/Dmcr rats. J Physiol Sci 2015; 65:417-25. [PMID: 25972297 PMCID: PMC10717666 DOI: 10.1007/s12576-015-0380-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 04/26/2015] [Indexed: 01/14/2023]
Abstract
Repeated cold stress (RCS) is known to transiently induce functional disorders associated with hypotension and hyperalgesia. In this study, we investigated the effects of RCS (24 and 4 °C alternately at 30-min intervals during the day and 4 °C at night for 2 days, followed by 4 °C on the next 2 consecutive nights) on the thresholds for cutaneous mechanical pain responses and on peripheral expression of "pain-related genes" in SHRSP5/Dmcr rats, which are derived from stroke-prone spontaneously hypertensive rats. To define genes peripherally regulated by RCS, we detected changes in the expression of pain-related genes in dorsal root ganglion cells by PCR-based cDNA subtraction analysis or DNA microarray analysis, and confirmed the changes by RT-PCR. We found significantly changed expression in eight pain-related genes (upregulated: Fyn, St8sia1, and Tac 1; downregulated: Ctsb, Fstl1, Itpr1, Npy, S100a10). At least some of these genes may play key roles in hyperalgesia induced by RCS.
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Affiliation(s)
- Yasuko Kozaki
- College of Pharmacy, Kinjo Gakuin University, 2-1723 Ohmori, Moriyama-ku, Nagoya, 463-8521, Japan,
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Pillarisetti S, Khanna I. A multimodal disease modifying approach to treat neuropathic pain--inhibition of soluble epoxide hydrolase (sEH). Drug Discov Today 2015; 20:1382-90. [PMID: 26259523 DOI: 10.1016/j.drudis.2015.07.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 07/23/2015] [Accepted: 07/30/2015] [Indexed: 01/05/2023]
Abstract
Both neuronal and non-neuronal mechanisms have been proposed to contribute to neuropathic pain (NP). All currently approved treatments for NP modulate neuronal targets and provide only symptomatic relief. Here we review evidence that inhibition of soluble epoxide hydrolase (sEH), the enzyme that degrades epoxyeicosatrienoic acids (EETs), has potential to be a multimodal, disease modifying approach to treat NP: (1) EET actions involve both endogenous opioid system and the GABAergic systems thus provide superior pain relief compared to morphine or gabapentin, (2) EETs are directly anti-inflammatory and inhibit expression of inflammatory cytokines and adhesion molecules thus can prevent continued nerve damage; and (3) EETs promote nerve regeneration in cultured neurons. Thus, an sEH inhibitor will not only provide effective pain relief, but would also block further nerve damage and promote healing.
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104
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Identification of lncRNA expression profile in the spinal cord of mice following spinal nerve ligation-induced neuropathic pain. Mol Pain 2015; 11:43. [PMID: 26184882 PMCID: PMC4504460 DOI: 10.1186/s12990-015-0047-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 07/07/2015] [Indexed: 01/02/2023] Open
Abstract
Background Neuropathic pain that caused by lesion or dysfunction of the nervous system is associated with gene expression changes in the sensory pathway. Long noncoding RNAs (lncRNAs) have been reported to be able to regulate gene expression. Identifying lncRNA expression patterns in the spinal cord under normal and neuropathic pain conditions is essential for understanding the genetic mechanisms behind the pathogenesis of neuropathic pain. Results Spinal nerve ligation (SNL) induced rapid and persistent pain hypersensitivity, characterized by mechanical allodynia and heat hyperalgesia. Meanwhile, astrocytes and microglia were dramatically activated in the ipsilateral spinal cord dorsal horn at 10 days after SNL. Further lncRNA microarray and mRNA microarray analysis showed that the expression profiles of lncRNA and mRNA between SNL and sham-operated mice were greatly changed at 10 days. The 511 differentially expressed (>2 fold) lncRNAs (366 up-regulated, 145 down-regulated) and 493 mRNAs (363 up-regulated, 122 down-regulated) were finally identified. The expression patterns of several lncRNAs and mRNAs were further confirmed by qPCR. Functional analysis of differentially expressed (DE) mRNAs showed that the most significant enriched biological processes of up-regulated genes in SNL include immune response, defense response, and inflammation response, which are important pathogenic mechanisms underlying neuropathic pain. 35 DE lncRNAs have neighboring or overlapping DE mRNAs in genome, which is related to Toll-like receptor signaling, cytokine–cytokine receptor interaction, and peroxisome proliferator-activated receptor signaling pathway. Conclusion Our findings uncovered the expression pattern of lncRNAs and mRNAs in the mice spinal cord under neuropathic pain condition. These lncRNAs and mRNAs may represent new therapeutic targets for the treatment of neuropathic pain.
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106
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Circulating microRNA Signatures in Rodent Models of Pain. Mol Neurobiol 2015; 53:3416-3427. [DOI: 10.1007/s12035-015-9281-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 06/02/2015] [Indexed: 01/29/2023]
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Coggan JS, Sejnowski TJ, Prescott SA. Cooperativity between remote sites of ectopic spiking allows afterdischarge to be initiated and maintained at different locations. J Comput Neurosci 2015; 39:17-28. [PMID: 25929191 DOI: 10.1007/s10827-015-0562-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 04/08/2015] [Accepted: 04/13/2015] [Indexed: 12/22/2022]
Abstract
Many symptoms of nerve damage arise from ectopic spiking caused by hyperexcitability. Ectopic spiking can originate at the site of axonal damage and elsewhere within affected neurons. This raises the question of whether localized damage elicits cell-wide changes in excitability and/or if localized changes in excitability can drive abnormal spiking at remote locations. Computer modeling revealed an example of the latter involving afterdischarge (AD)--stimulus-evoked spiking that outlasts stimulation. We found that AD originating in a hyperexcitable region of axon could shift to the soma where it was maintained. This repositioning of ectopic spike initiation was independent of distance between the two sites but relied on the rate and number of ectopic spikes originating from the first site. Nonlinear dynamical analysis of a reduced model demonstrated that properties which rendered the axonal site prone to initiating AD discouraged it from maintaining AD, whereas the soma had the inverse properties thus enabling the two sites to interact cooperatively. A first phase of AD originating in the axon could, by providing sufficient drive to trigger somatic AD, give way to a second phase of AD originating in the soma such that spiking continued when axonal AD failed. Ectopic spikes originating from the soma during phase 2 AD propagated successfully through the defunct site of axonal spike initiation. This novel mechanism whereby ectopic spiking at one site facilitates ectopic spiking at another site is likely to contribute to the chronification of hyperexcitability in conditions such as neuropathic pain.
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Affiliation(s)
- Jay S Coggan
- NeuroLinx Research Institute, PO Box 13668, La Jolla, CA, 92039, USA,
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108
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Andia I, Rubio-Azpeitia E, Maffulli N. Platelet-rich plasma modulates the secretion of inflammatory/angiogenic proteins by inflamed tenocytes. Clin Orthop Relat Res 2015; 473:1624-34. [PMID: 25670657 PMCID: PMC4385357 DOI: 10.1007/s11999-015-4179-z] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Platelet-rich plasma therapies for tendinopathy appear to provide moderate pain reduction. However, the biological mechanisms behind the observed clinical effects remain poorly characterized. QUESTIONS/PURPOSES The purpose of this study was to explore whether platelet-rich plasma modifies the inflammatory/angiogenic status of already inflamed tenocytes by examining (1) gene expression; (2) modulation of chemokine and interleukin secretion; and (3) differences between healthy and tendinopathic tenocytes. METHODS Cells from both healthy and tendinopathic tendons were exposed to interleukin (IL)-1ß and after treated with platelet-rich plasma. Modifications in the expression of selected genes were assessed by real-time reverse transcription-polymerase chain reaction and changes in secretion of angiogenic/inflammatory molecules by enzyme-linked immunosorbent assay. Platelet-rich plasma-induced changes in tendinopathic cells were compared with normal after normalizing platelet-rich plasma data against IL-1ß status in each specific sample. RESULTS In IL-1ß-exposed cells, platelet-rich plasma downregulates expression of IL-6/CXCL-6 (mean, 0.015; 95% confidence interval [CI], 0.005-0.025; p = 0.026), IL-6R (mean, 0.61; 95% CI, 0.27-0.95; p = 0.029), and IL-8/CXCL-8 (mean, 0.02; 95% CI, 0.007-0.023; p = 0.026). Secretion of IL-6/CXCL6, 0.35 (95% CI, 0.3-0.4; p = 0.002), IL-8/CXCL8, 0.55 (95% CI, 0.5-0.7; p = 0.01), and monocyte chemoattractant protein-1/CCL2, 0.40 (95% CI, 0.2-0.6; p = 0.001) was reduced by platelet-rich plasma, whereas vascular endothelial growth factor increased by twofold, (95% CI, 1.7-2.3; p < 0.001). RANTES/CCL5 increased by10-fold (95% CI, 4-17) and hepatocyte growth factor by 21-fold (95% CI, 0.2-42) in tendinopathic and by 2.3-fold (95% CI, 2-3) and threefold (95% CI, 1-5) in normal cells (p = 0.005 for both). CONCLUSIONS Platelet-rich plasma induces an immunomodulatory and proangiogenic phenotype consistent with healing mechanisms with few differences between tendinopathic and normal cells. CLINICAL RELEVANCE Platelet-rich plasma injections in pathological and nearby tissue might help to recover tendon homeostasis.
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Affiliation(s)
- Isabel Andia
- Regenerative medicine Group, Biocruces Health Research Institute, Cruces University Hospital, 48903 Barakaldo, Spain
| | - Eva Rubio-Azpeitia
- Regenerative medicine Group, Biocruces Health Research Institute, Cruces University Hospital, 48903 Barakaldo, Spain
| | - Nicola Maffulli
- Department of Musculoskeletal Disorders, University of Salerno School of Medicine and Surgery, Salerno, Italy ,Barts and the London School of Medicine and Dentistry, Centre for Sports and Exercise Medicine, Mile End Hospital, Queen Mary University of London, 275 Bancroft Road, London, E1 4DG UK
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109
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Austin PJ, Bembrick AL, Denyer GS, Keay KA. Injury-Dependent and Disability-Specific Lumbar Spinal Gene Regulation following Sciatic Nerve Injury in the Rat. PLoS One 2015; 10:e0124755. [PMID: 25905723 PMCID: PMC4408097 DOI: 10.1371/journal.pone.0124755] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 03/06/2015] [Indexed: 12/23/2022] Open
Abstract
Allodynia, hyperalgesia and spontaneous pain are cardinal sensory signs of neuropathic pain. Clinically, many neuropathic pain patients experience affective-motivational state changes, including reduced familial and social interactions, decreased motivation, anhedonia and depression which are severely debilitating. In earlier studies we have shown that sciatic nerve chronic constriction injury (CCI) disrupts social interactions, sleep-wake-cycle and endocrine function in one third of rats, a subgroup reliably identified six days after injury. CCI consistently produces allodynia and hyperalgesia, the intensity of which was unrelated either to the altered social interactions, sleep-wake-cycle or endocrine changes. This decoupling of the sensory consequences of nerve injury from the affective-motivational changes is reported in both animal experiments and human clinical data. The sensory changes triggered by CCI are mediated primarily by functional changes in the lumbar dorsal horn, however, whether lumbar spinal changes may drive different affective-motivational states has never been considered. In these studies, we used microarrays to identify the unique transcriptomes of rats with altered social behaviours following sciatic CCI to determine whether specific patterns of lumbar spinal adaptations characterised this subgroup. Rats underwent CCI and on the basis of reductions in dominance behaviour in resident-intruder social interactions were categorised as having Pain & Disability, Pain & Transient Disability or Pain alone. We examined the lumbar spinal transcriptomes two and six days after CCI. Fifty-four ‘disability-specific’ genes were identified. Sixty-five percent were unique to Pain & Disability rats, two-thirds of which were associated with neurotransmission, inflammation and/or cellular stress. In contrast, 40% of genes differentially regulated in rats without disabilities were involved with more general homeostatic processes (cellular structure, transcription or translation). We suggest that these patterns of gene expression lead to either the expression of disability, or to resilience and recovery, by modifying local spinal circuitry at the origin of ascending supraspinal pathways.
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Affiliation(s)
- Paul J. Austin
- School of Medical Sciences (Anatomy & Histology), The University of Sydney, Sydney, NSW, Australia
| | - Alison L. Bembrick
- School of Medical Sciences (Anatomy & Histology), The University of Sydney, Sydney, NSW, Australia
| | - Gareth S. Denyer
- School of Molecular Bioscience, The University of Sydney, Sydney, NSW, Australia
| | - Kevin A. Keay
- School of Medical Sciences (Anatomy & Histology), The University of Sydney, Sydney, NSW, Australia
- * E-mail:
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Crow M, Khovanov N, Kelleher JH, Sharma S, Grant AD, Bogdanov Y, Wood JN, McMahon SB, Denk F. HDAC4 is required for inflammation-associated thermal hypersensitivity. FASEB J 2015; 29:3370-8. [PMID: 25903105 PMCID: PMC4511203 DOI: 10.1096/fj.14-264440] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 04/16/2015] [Indexed: 01/04/2023]
Abstract
Transcriptional alterations are characteristic of persistent pain states, but the key regulators remain elusive. HDAC4 is a transcriptional corepressor that has been linked to synaptic plasticity and neuronal excitability, mechanisms that may be involved in peripheral and central sensitization. Using a conditional knockout (cKO) strategy in mice, we sought to determine whether the loss of HDAC4 would have implications for sensory neuron transcription and nociception. HDAC4 was found to be largely unnecessary for transcriptional regulation of naïve sensory neurons but was essential for appropriate transcriptional responses after injury, with Calca and Trpv1 expression consistently down-regulated in HDAC4 cKO compared to levels in the littermate controls (0.2-0.44-fold change, n = 4 in 2 separate experiments). This down-regulation corresponded to reduced sensitivity to 100 nM capsaicin in vitro (IC50 = 230 ± 20 nM, 76 ± 4.4% wild-type capsaicin responders vs. 56.9 ± 4.7% HDAC4 cKO responders) and to reduced thermal hypersensitivity in the complete Freund's adjuvant (CFA) model of inflammatory pain (1.3-1.4-fold improvement over wild-type controls; n = 5-12, in 2 separate experiments). These data indicate that HDAC4 is a novel inflammatory pain mediator and may be a good therapeutic target, capable of orchestrating the regulation of multiple downstream effectors.
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Affiliation(s)
- Megan Crow
- *Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom, UCL Genomics, Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
| | - Nikita Khovanov
- *Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom, UCL Genomics, Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
| | - Jayne H Kelleher
- *Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom, UCL Genomics, Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
| | - Simone Sharma
- *Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom, UCL Genomics, Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
| | - Andrew D Grant
- *Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom, UCL Genomics, Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
| | - Yury Bogdanov
- *Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom, UCL Genomics, Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
| | - John N Wood
- *Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom, UCL Genomics, Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
| | - Stephen B McMahon
- *Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom, UCL Genomics, Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
| | - Franziska Denk
- *Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom, UCL Genomics, Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
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111
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Zhang J, Banerjee B. Role of MicroRNA in Visceral Pain. J Neurogastroenterol Motil 2015; 21:159-71. [PMID: 25843071 PMCID: PMC4398244 DOI: 10.5056/jnm15027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 03/19/2015] [Accepted: 03/27/2015] [Indexed: 12/30/2022] Open
Abstract
The long-lasting nociceptive transmission under various visceral pain conditions involves transcriptional and/or translational alteration in neurotransmitter and receptor expression as well as modification of neuronal function, morphology and synaptic connections. Although it is largely unknown how such changes in posttranscriptional expression induce visceral pain, recent evidence strongly suggests an important role for microRNAs (miRNAs, small non-coding RNAs) in the cellular plasticity underlying chronic visceral pain. MicroRNAs are small noncoding RNA endogenously produced in our body and act as a major regulator of gene expression by either through cleavage or translational repression of the target gene. This regulation is essential for the normal physiological function but when disturbed can result in pathological conditions. Usually one miRNA has multiple targets and target mRNAs are regulated in a combinatorial fashion by multiple miRNAs. In recent years, many studies have been performed to delineate the posttranscriptional regulatory role of miRNAs in different tissues under various nociceptive stimuli. In this review, we intend to discuss the recent development in miRNA research with special emphases on miRNAs and their targets responsible for long term sensitization in chronic pain conditions. In addition, we review miRNAs expression and function data for different animal pain models and also the recent progress in research on miRNA-based therapeutic targets for the treatment of chronic pain.
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Affiliation(s)
- Jian Zhang
- Division of Gastroenterology and Hepatology, Department of Medicine, Medical College of Wisconsin Milwaukee, WI , USA
| | - Banani Banerjee
- Division of Gastroenterology and Hepatology, Department of Medicine, Medical College of Wisconsin Milwaukee, WI , USA
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Stankiewicz AM, Goscik J, Swiergiel AH, Majewska A, Wieczorek M, Juszczak GR, Lisowski P. Social stress increases expression of hemoglobin genes in mouse prefrontal cortex. BMC Neurosci 2014; 15:130. [PMID: 25472829 PMCID: PMC4269175 DOI: 10.1186/s12868-014-0130-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Accepted: 11/18/2014] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND In order to better understand the effects of social stress on the prefrontal cortex, we investigated gene expression in mice subjected to acute and repeated social encounters of different duration using microarrays. RESULTS The most important finding was identification of hemoglobin genes (Hbb-b1, Hbb-b2, Hba-a1, Hba-a2, Beta-S) as potential markers of chronic social stress in mice. Expression of these genes was progressively increased in animals subjected to 8 and 13 days of repeated stress and was correlated with altered expression of Mgp (Mglap), Fbln1, 1500015O10Rik (Ecrg4), SLC16A10, and Mndal. Chronic stress increased also expression of Timp1 and Ppbp that are involved in reaction to vascular injury. Acute stress did not affect expression of hemoglobin genes but it altered expression of Fam107a (Drr1) and Agxt2l1 (Etnppl) that have been implicated in psychiatric diseases. CONCLUSIONS The observed up-regulation of genes associated with vascular system and brain injury suggests that stressful social encounters may affect brain function through the stress-induced dysfunction of the vascular system.
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Affiliation(s)
- Adrian M Stankiewicz
- Department of Animal Behavior, Institute of Genetics and Animal Breeding, Jastrzebiec, ul. Postepu 36A, 05-552, Magdalenka, Poland.
| | - Joanna Goscik
- Faculty of Computer Science, Bialystok University of Technology, Wiejska 45A, 15-351, Bialystok, Poland.
| | - Artur H Swiergiel
- Department of Human and Animal Physiology, Institute of Biology, University of Gdansk, 80-308, Gdansk, Poland.
| | - Alicja Majewska
- Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences, Warsaw, Poland.
| | - Marek Wieczorek
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lodz, Pomorska, 141/143, Poland.
| | - Grzegorz R Juszczak
- Department of Animal Behavior, Institute of Genetics and Animal Breeding, Jastrzebiec, ul. Postepu 36A, 05-552, Magdalenka, Poland.
| | - Paweł Lisowski
- Department of Molecular Biology, Institute of Genetics and Animal Breeding, Jastrzebiec, ul. Postepu 36A, 05-552, Magdalenka, Poland. .,iPS Cell-Based Disease Modeling Group, Max-Delbrück-Center for Molecular Medicine (MDC) in the Helmholtz Association, 13092, Berlin, Germany.
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113
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Tang S, Ding Y, Sibille E, Mogil J, Lariviere WR, Tseng GC. Imputation of Truncated p-Values For Meta-Analysis Methods and Its Genomic Application. Ann Appl Stat 2014; 8:2150-2174. [PMID: 25541588 DOI: 10.1214/14-aoas747] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Microarray analysis to monitor expression activities in thousands of genes simultaneously has become routine in biomedical research during the past decade. a tremendous amount of expression profiles are generated and stored in the public domain and information integration by meta-analysis to detect differentially expressed (DE) genes has become popular to obtain increased statistical power and validated findings. Methods that aggregate transformed p-value evidence have been widely used in genomic settings, among which Fisher's and Stouffer's methods are the most popular ones. In practice, raw data and p-values of DE evidence are often not available in genomic studies that are to be combined. Instead, only the detected DE gene lists under a certain p-value threshold (e.g., DE genes with p-value < 0.001) are reported in journal publications. The truncated p-value information makes the aforementioned meta-analysis methods inapplicable and researchers are forced to apply a less efficient vote counting method or naïvely drop the studies with incomplete information. The purpose of this paper is to develop effective meta-analysis methods for such situations with partially censored p-values. We developed and compared three imputation methods-mean imputation, single random imputation and multiple imputation-for a general class of evidence aggregation methods of which Fisher's and Stouffer's methods are special examples. The null distribution of each method was analytically derived and subsequent inference and genomic analysis frameworks were established. Simulations were performed to investigate the type Ierror, power and the control of false discovery rate (FDR) for (correlated) gene expression data. The proposed methods were applied to several genomic applications in colorectal cancer, pain and liquid association analysis of major depressive disorder (MDD). The results showed that imputation methods outperformed existing naïve approaches. Mean imputation and multiple imputation methods performed the best and are recommended for future applications.
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Jamieson DG, Moss A, Kennedy M, Jones S, Nenadic G, Robertson DL, Sidders B. The pain interactome: connecting pain-specific protein interactions. Pain 2014; 155:2243-52. [PMID: 24978826 PMCID: PMC4247380 DOI: 10.1016/j.pain.2014.06.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 06/13/2014] [Accepted: 06/23/2014] [Indexed: 11/29/2022]
Abstract
Understanding the molecular mechanisms associated with disease is a central goal of modern medical research. As such, many thousands of experiments have been published that detail individual molecular events that contribute to a disease. Here we use a semi-automated text mining approach to accurately and exhaustively curate the primary literature for chronic pain states. In so doing, we create a comprehensive network of 1,002 contextualized protein-protein interactions (PPIs) specifically associated with pain. The PPIs form a highly interconnected and coherent structure, and the resulting network provides an alternative to those derived from connecting genes associated with pain using interactions that have not been shown to occur in a painful state. We exploit the contextual data associated with our interactions to analyse subnetworks specific to inflammatory and neuropathic pain, and to various anatomical regions. Here, we identify potential targets for further study and several drug-repurposing opportunities. Finally, the network provides a framework for the interpretation of new data within the field of pain.
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Affiliation(s)
- Daniel G Jamieson
- Computational and Evolutionary Biology, Faculty of Life Sciences, University of Manchester, Manchester, UK; Computer Science, Faculty of Engineering and Physical Sciences, University of Manchester, Manchester, UK
| | - Andrew Moss
- Neusentis, Pfizer, Worldwide Research & Development, Cambridge, UK
| | - Michael Kennedy
- Neusentis, Pfizer, Worldwide Research & Development, Cambridge, UK
| | - Sherrie Jones
- Cancer Research UK Manchester Institute, University of Manchester, Manchester, UK
| | - Goran Nenadic
- Computer Science, Faculty of Engineering and Physical Sciences, University of Manchester, Manchester, UK; Manchester Institute of Biotechnology, University of Manchester, Manchester, UK
| | - David L Robertson
- Computational and Evolutionary Biology, Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - Ben Sidders
- Neusentis, Pfizer, Worldwide Research & Development, Cambridge, UK.
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Enhanced excitability of primary sensory neurons and altered gene expression of neuronal ion channels in dorsal root ganglion in paclitaxel-induced peripheral neuropathy. Anesthesiology 2014; 120:1463-75. [PMID: 24534904 DOI: 10.1097/aln.0000000000000176] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The mechanism of chemotherapy-induced peripheral neuropathy after paclitaxel treatment is not well understood. Given the poor penetration of paclitaxel into central nervous system, peripheral nervous system is most at risk. METHODS Intrinsic membrane properties of dorsal root ganglion neurons were studied by intracellular recordings. Multiple-gene real-time polymerase chain reaction array was used to investigate gene expression of dorsal root ganglion neuronal ion channels. RESULTS Paclitaxel increased the incidence of spontaneous activity from 4.8 to 27.1% in large-sized and from 0 to 33.3% in medium-sized neurons. Paclitaxel decreased the rheobase (nA) from 1.6 ± 0.1 to 0.8 ± 0.1 in large-sized, from 1.5 ± 0.2 to 0.6 ± 0.1 in medium-sized, and from 1.6 ± 0.2 to 1.0 ± 0.1 in small-sized neurons. After paclitaxel treatment, other characteristics of membrane properties in each group remained the same except that Aδ neurons showed shorter action potential fall time (ms) (1.0 ± 0.2, n = 10 vs. 1.8 ± 0.3, n = 9, paclitaxel vs. vehicle). Meanwhile, real-time polymerase chain reaction array revealed an alteration in expression of some neuronal ion channel genes including up-regulation of hyperpolarization-activated cyclic nucleotide-gated channel 1 (fold change 1.76 ± 0.06) and Nav1.7 (1.26 ± 0.02) and down-regulation of Kir channels (Kir1.1, 0.73 ± 0.05, Kir3.4, 0.66 ± 0.06) in paclitaxel-treated animals. CONCLUSION The increased neuronal excitability and the changes in gene expression of some neuronal ion channels in dorsal root ganglion may provide insight into the molecular and cellular basis of paclitaxel-induced neuropathy, which may lead to novel therapeutic strategies.
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Cheng CP, DeBoever C, Frazer KA, Liu YC, Tseng VS. MiningABs: mining associated biomarkers across multi-connected gene expression datasets. BMC Bioinformatics 2014; 15:173. [PMID: 24909518 PMCID: PMC4068973 DOI: 10.1186/1471-2105-15-173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 06/03/2014] [Indexed: 11/12/2022] Open
Abstract
Background Human disease often arises as a consequence of alterations in a set of associated genes rather than alterations to a set of unassociated individual genes. Most previous microarray-based meta-analyses identified disease-associated genes or biomarkers independent of genetic interactions. Therefore, in this study, we present the first meta-analysis method capable of taking gene combination effects into account to efficiently identify associated biomarkers (ABs) across different microarray platforms. Results We propose a new meta-analysis approach called MiningABs to mine ABs across different array-based datasets. The similarity between paired probe sequences is quantified as a bridge to connect these datasets together. The ABs can be subsequently identified from an “improved” common logit model (c-LM) by combining several sibling-like LMs in a heuristic genetic algorithm selection process. Our approach is evaluated with two sets of gene expression datasets: i) 4 esophageal squamous cell carcinoma and ii) 3 hepatocellular carcinoma datasets. Based on an unbiased reciprocal test, we demonstrate that each gene in a group of ABs is required to maintain high cancer sample classification accuracy, and we observe that ABs are not limited to genes common to all platforms. Investigating the ABs using Gene Ontology (GO) enrichment, literature survey, and network analyses indicated that our ABs are not only strongly related to cancer development but also highly connected in a diverse network of biological interactions. Conclusions The proposed meta-analysis method called MiningABs is able to efficiently identify ABs from different independently performed array-based datasets, and we show its validity in cancer biology via GO enrichment, literature survey and network analyses. We postulate that the ABs may facilitate novel target and drug discovery, leading to improved clinical treatment. Java source code, tutorial, example and related materials are available at “http://sourceforge.net/projects/miningabs/”.
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Affiliation(s)
| | | | - Kelly A Frazer
- Department of Computer Science and Information Engineering, National Cheng Kung University, Tainan, Taiwan.
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Dawes JM, Antunes-Martins A, Perkins JR, Paterson KJ, Sisignano M, Schmid R, Rust W, Hildebrandt T, Geisslinger G, Orengo C, Bennett DL, McMahon SB. Genome-wide transcriptional profiling of skin and dorsal root ganglia after ultraviolet-B-induced inflammation. PLoS One 2014; 9:e93338. [PMID: 24732968 PMCID: PMC3986071 DOI: 10.1371/journal.pone.0093338] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Indexed: 11/18/2022] Open
Abstract
Ultraviolet-B (UVB)-induced inflammation produces a dose-dependent mechanical and thermal hyperalgesia in both humans and rats, most likely via inflammatory mediators acting at the site of injury. Previous work has shown that the gene expression of cytokines and chemokines is positively correlated between species and that these factors can contribute to UVB-induced pain. In order to investigate other potential pain mediators in this model we used RNA-seq to perform genome-wide transcriptional profiling in both human and rat skin at the peak of hyperalgesia. In addition we have also measured transcriptional changes in the L4 and L5 DRG of the rat model. Our data show that UVB irradiation produces a large number of transcriptional changes in the skin: 2186 and 3888 genes are significantly dysregulated in human and rat skin, respectively. The most highly up-regulated genes in human skin feature those encoding cytokines (IL6 and IL24), chemokines (CCL3, CCL20, CXCL1, CXCL2, CXCL3 and CXCL5), the prostanoid synthesising enzyme COX-2 and members of the keratin gene family. Overall there was a strong positive and significant correlation in gene expression between the human and rat (R = 0.8022). In contrast to the skin, only 39 genes were significantly dysregulated in the rat L4 and L5 DRGs, the majority of which had small fold change values. Amongst the most up-regulated genes in DRG were REG3B, CCL2 and VGF. Overall, our data shows that numerous genes were up-regulated in UVB irradiated skin at the peak of hyperalgesia in both human and rats. Many of the top up-regulated genes were cytokines and chemokines, highlighting again their potential as pain mediators. However many other genes were also up-regulated and might play a role in UVB-induced hyperalgesia. In addition, the strong gene expression correlation between species re-emphasises the value of the UVB model as translational tool to study inflammatory pain.
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MESH Headings
- Animals
- Antigens, Neoplasm/metabolism
- Biomarkers, Tumor/metabolism
- Chemokine CCL2/metabolism
- Ganglia, Spinal/metabolism
- Ganglia, Spinal/pathology
- Ganglia, Spinal/radiation effects
- Gene Expression Profiling
- Gene Expression Regulation/radiation effects
- Genome/genetics
- Humans
- Inflammation/genetics
- Inflammation/pathology
- Lectins, C-Type/metabolism
- Male
- Models, Biological
- Pancreatitis-Associated Proteins
- Rats, Wistar
- Reference Standards
- Reproducibility of Results
- Sequence Analysis, RNA
- Skin/metabolism
- Skin/pathology
- Skin/radiation effects
- Transcription, Genetic/radiation effects
- Ultraviolet Rays
- Up-Regulation/genetics
- Up-Regulation/radiation effects
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Affiliation(s)
- John M. Dawes
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Ana Antunes-Martins
- Wolfson Centre for Age-Related Disease, King's College London, London, United Kingdom
| | - James R. Perkins
- Department of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Kathryn J. Paterson
- Wolfson Centre for Age-Related Disease, King's College London, London, United Kingdom
| | - Marco Sisignano
- Institute of Clinical Pharmacology, Pharmazentrum Frankfurt/Zentrum fuer Arzneimittelforschung, -Entwicklung und -Sicherheit (ZAFES), University Hospital, Goethe-University, Frankfurt am Main, Germany
| | - Ramona Schmid
- Boehringer Ingelheim Pharma GmbH & Co. KG, Target Discovery Research Germany, Biberach an der Riß, Germany
| | - Werner Rust
- Boehringer Ingelheim Pharma GmbH & Co. KG, Target Discovery Research Germany, Biberach an der Riß, Germany
| | - Tobias Hildebrandt
- Boehringer Ingelheim Pharma GmbH & Co. KG, Target Discovery Research Germany, Biberach an der Riß, Germany
| | - Gerd Geisslinger
- Institute of Clinical Pharmacology, Pharmazentrum Frankfurt/Zentrum fuer Arzneimittelforschung, -Entwicklung und -Sicherheit (ZAFES), University Hospital, Goethe-University, Frankfurt am Main, Germany
| | - Christine Orengo
- Department of Structural and Molecular Biology, University College London, London, United Kingdom
| | - David L. Bennett
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Stephen B. McMahon
- Wolfson Centre for Age-Related Disease, King's College London, London, United Kingdom
- * E-mail:
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Ratté S, Zhu Y, Lee KY, Prescott SA. Criticality and degeneracy in injury-induced changes in primary afferent excitability and the implications for neuropathic pain. eLife 2014; 3:e02370. [PMID: 24692450 PMCID: PMC3970756 DOI: 10.7554/elife.02370] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Neuropathic pain remains notoriously difficult to treat despite numerous drug targets. Here, we offer a novel explanation for this intractability. Computer simulations predicted that qualitative changes in primary afferent excitability linked to neuropathic pain arise through a switch in spike initiation dynamics when molecular pathologies reach a tipping point (criticality), and that this tipping point can be reached via several different molecular pathologies (degeneracy). We experimentally tested these predictions by pharmacologically blocking native conductances and/or electrophysiologically inserting virtual conductances. Multiple different manipulations successfully reproduced or reversed neuropathic changes in primary afferents from naïve or nerve-injured rats, respectively, thus confirming the predicted criticality and its degenerate basis. Degeneracy means that several different molecular pathologies are individually sufficient to cause hyperexcitability, and because several such pathologies co-occur after nerve injury, that no single pathology is uniquely necessary. Consequently, single-target-drugs can be circumvented by maladaptive plasticity in any one of several ion channels. DOI:http://dx.doi.org/10.7554/eLife.02370.001 Although the pain associated with an injury is unpleasant, it normally serves an important purpose: to make you avoid its source. However, some pain appears to arise from nowhere. Frustratingly, this type of pain, known as neuropathic pain, does not respond to common painkillers and is thus very difficult to treat. The neurons that transmit pain and other sensory information do so using electrical signals. In response to a stimulus, ions travel through channels in the membrane of a neuron, which leads to a change in the electrical potential of the membrane. When this change is large enough, a voltage spike is produced: this signal is ultimately transmitted to the brain. When certain neurons fire too easily or too often, neuropathic pain can arise. This hyperexcitability can make something painful feel even worse, or it can make things hurt that shouldn’t. To prevent this, extensive research has been devoted to identify drugs that target particular types of ion channels and block them. However, despite the discovery of many promising drugs, those drugs have been frustratingly ineffective in clinical trials. Using simulations and experiments, Ratté et al. have examined the behavior of a type of neuron that normally conducts information about touch, but the brain sometimes misinterprets this information as pain. Increasing the flow of ions through the cell membrane in these simulations eventually causes a ‘tipping point’ to be crossed, which triggers a dramatic, discontinuous change in spiking pattern. However, as several different types of ion channels contribute to the current, there are several different ways in which the tipping point can be crossed. This ability to produce the same result by multiple means is a common feature of complex systems. Known as degeneracy, it makes systems more robust, as a given result can still be achieved if one particular attempt to achieve this result fails. The work of Ratté et al. helps to explain why drugs that target just one type of ion channel may fail to relieve neuropathic pain: maladaptive changes in any one of several other ion channels may circumvent the therapeutic effect. DOI:http://dx.doi.org/10.7554/eLife.02370.002
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Affiliation(s)
- Stéphanie Ratté
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Canada
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Fairbanks CA, Peterson CD, Speltz RH, Riedl MS, Kitto KF, Dykstra JA, Braun PD, Sadahiro M, Salton SR, Vulchanova L. The VGF-derived peptide TLQP-21 contributes to inflammatory and nerve injury-induced hypersensitivity. Pain 2014; 155:1229-1237. [PMID: 24657450 DOI: 10.1016/j.pain.2014.03.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 03/03/2014] [Accepted: 03/14/2014] [Indexed: 12/30/2022]
Abstract
VGF (nonacronymic) is a granin-like protein that is packaged and proteolytically processed within the regulated secretory pathway. VGF and peptides derived from its processing have been implicated in neuroplasticity associated with learning, memory, depression, and chronic pain. In sensory neurons, VGF is rapidly increased following peripheral nerve injury and inflammation. Several bioactive peptides generated from the C-terminus of VGF have pronociceptive spinal effects. The goal of the present study was to examine the spinal effects of the peptide TLQP-21 and determine whether it participates in spinal mechanisms of persistent pain. Application of exogenous TLQP-21 induced dose-dependent thermal hyperalgesia in the warm-water immersion tail-withdrawal test. This hyperalgesia was inhibited by a p38 mitogen-activated protein kinase inhibitor, as well as inhibitors of cyclooxygenase and lipoxygenase. We used immunoneutralization of TLQP-21 to determine the function of the endogenous peptide in mechanisms underlying persistent pain. In mice injected intradermally with complete Freund adjuvant, intrathecal treatment with anti-TLQP-21 immediately prior to or 5hours after induction of inflammation dose-dependently inhibited tactile hypersensitivity and thermal hyperalgesia. Intrathecal anti-TL21 administration also attenuated the development and maintenance of tactile hypersensitivity in the spared nerve injury model of neuropathic pain. These results provide evidence that endogenous TLQP-21 peptide contributes to the mechanisms of spinal neuroplasticity after inflammation and nerve injury.
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Affiliation(s)
- Carolyn A Fairbanks
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA Department of Pharmaceutics, University of Minnesota, Minneapolis, MN, USA Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA Experimental and Clinical Pharmacology Graduate Program, University of Minnesota, Minneapolis, MN, USA Comparative and Molecular Biosciences Graduate Program, University of Minnesota, St. Paul, MN, USA Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, MN, USA
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Perkins JR, Antunes-Martins A, Calvo M, Grist J, Rust W, Schmid R, Hildebrandt T, Kohl M, Orengo C, McMahon SB, Bennett DLH. A comparison of RNA-seq and exon arrays for whole genome transcription profiling of the L5 spinal nerve transection model of neuropathic pain in the rat. Mol Pain 2014; 10:7. [PMID: 24472155 PMCID: PMC4021616 DOI: 10.1186/1744-8069-10-7] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 01/02/2014] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The past decade has seen an abundance of transcriptional profiling studies of preclinical models of persistent pain, predominantly employing microarray technology. In this study we directly compare exon microarrays to RNA-seq and investigate the ability of both platforms to detect differentially expressed genes following nerve injury using the L5 spinal nerve transection model of neuropathic pain. We also investigate the effects of increasing RNA-seq sequencing depth. Finally we take advantage of the "agnostic" approach of RNA-seq to discover areas of expression outside of annotated exons that show marked changes in expression following nerve injury. RESULTS RNA-seq and microarrays largely agree in terms of the genes called as differentially expressed. However, RNA-seq is able to interrogate a much larger proportion of the genome. It can also detect a greater number of differentially expressed genes than microarrays, across a wider range of fold changes and is able to assign a larger range of expression values to the genes it measures. The number of differentially expressed genes detected increases with sequencing depth. RNA-seq also allows the discovery of a number of genes displaying unusual and interesting patterns of non-exonic expression following nerve injury, an effect that cannot be detected using microarrays. CONCLUSION We recommend the use of RNA-seq for future high-throughput transcriptomic experiments in pain studies. RNA-seq allowed the identification of a larger number of putative candidate pain genes than microarrays and can also detect a wider range of expression values in a neuropathic pain model. In addition, RNA-seq can interrogate the whole genome regardless of prior annotations, being able to detect transcription from areas of the genome not currently annotated as exons. Some of these areas are differentially expressed following nerve injury, and may represent novel genes or isoforms. We also recommend the use of a high sequencing depth in order to detect differential expression for genes with low levels of expression.
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Affiliation(s)
- James R Perkins
- Department of Structural and Molecular Biology, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
- Laboratorio de Investigacion, Fundacion IMABIS, Avda. Jorge Luis Borges nº15 Bl.3 Pl.3, 29010, Malaga, Spain
| | - Ana Antunes-Martins
- The Wolfson Centre for Age-Related Diseases, Wolfson Wing, Hodgkin Building, King’s College London, Guy's Campus, London Bridge, London SE1 1UL, UK
| | - Margarita Calvo
- The Wolfson Centre for Age-Related Diseases, Wolfson Wing, Hodgkin Building, King’s College London, Guy's Campus, London Bridge, London SE1 1UL, UK
| | - John Grist
- The Wolfson Centre for Age-Related Diseases, Wolfson Wing, Hodgkin Building, King’s College London, Guy's Campus, London Bridge, London SE1 1UL, UK
| | - Werner Rust
- Boehringer Ingelheim Pharma GmbH & Co. KG, Target Discovery Research Germany, Birkendorferstraße 67, 88397, Biberach an der Riß, Germany
| | - Ramona Schmid
- Boehringer Ingelheim Pharma GmbH & Co. KG, Target Discovery Research Germany, Birkendorferstraße 67, 88397, Biberach an der Riß, Germany
| | - Tobias Hildebrandt
- Boehringer Ingelheim Pharma GmbH & Co. KG, Target Discovery Research Germany, Birkendorferstraße 67, 88397, Biberach an der Riß, Germany
| | - Matthias Kohl
- Department of Medical and Life Sciences, Furtwangen University, Jakob-Kienzle-Str. 17, D-78054 VS-Schwenningen, Germany
| | - Christine Orengo
- Department of Structural and Molecular Biology, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Stephen B McMahon
- The Wolfson Centre for Age-Related Diseases, Wolfson Wing, Hodgkin Building, King’s College London, Guy's Campus, London Bridge, London SE1 1UL, UK
| | - David LH Bennett
- The Wolfson Centre for Age-Related Diseases, Wolfson Wing, Hodgkin Building, King’s College London, Guy's Campus, London Bridge, London SE1 1UL, UK
- Nuffield Department of Clinical Neurosciences, Level 6, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, England
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Spatiotemporal changes in NSF expression of DRG neurons in a rat model of spinal nerve ligation. J Mol Neurosci 2014; 53:645-53. [PMID: 24443234 DOI: 10.1007/s12031-014-0231-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Accepted: 01/07/2014] [Indexed: 12/13/2022]
Abstract
N-ethylmaleimide-sensitive fusion (NSF) protein is a homohexameric ATPase that binds to the GluR2 subunit of α-amino-3-hydroxy-5-methyl-4-isoxazoleproprionic acid (AMPA) receptors. The stability and movement of AMPA receptors at synapses are important factors that control synaptic strength. NSF is involved in the surface expression regulation of AMPA receptors and consequently synaptic activity. Reduced expression of NSF or reduced interaction of NSF with GluR2 leads to a number of neurological disorders. Using a rat model of L5 spinal nerve ligation (SNL), we investigated the temporal and spatial expression of NSF in injured L5 and uninjured L4 dorsal root ganglion (DRG) neurons during mechanical allodynia. L5 SNL led to a significant decrease of NSF in both L4 and L5 DRGs observed at 3, 7, and 14 days after injury. In particular, NSF expression in calcitonin gene-related peptide (CGRP)-immunoreactive (IR) and IB4-IR neurons was reduced, whereas NSF expression in NF-200-IR neurons remained unaltered. These results indicate a role for NSF in CGRP-IR and IB4-IR neurons in SNL, with reduced NSF expression possibly contributing to SNL derived neuropathic pain.
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Lessans S, Dorsey SG. The role for epigenetic modifications in pain and analgesia response. Nurs Res Pract 2013; 2013:961493. [PMID: 24228176 PMCID: PMC3817675 DOI: 10.1155/2013/961493] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 09/12/2013] [Indexed: 12/12/2022] Open
Abstract
Pain remains a poorly understood and managed symptom. A limited mechanistic understanding of interindividual differences in pain and analgesia response shapes current approaches to assessment and treatment. Opportunities exist to improve pain care through increased understanding of how dynamic epigenomic remodeling shapes injury, illness, pain, and treatment response. Tightly regulated alterations of the DNA-histone chromatin complex enable cells to control transcription, replication, gene expression, and protein production. Pathological alterations to chromatin shape the ability of the cell to respond to physiologic and environmental cues leading to disease and reduced treatment effectiveness. This review provides an overview of critical epigenetic processes shaping pathology and pain, highlights current research support for the role of epigenomic modification in the development of chronic pain, and summarizes the therapeutic potential to alter epigenetic processes to improve health outcomes.
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Affiliation(s)
- Sherrie Lessans
- School of Nursing, University of Maryland, Baltimore, USA
- Program in Neuroscience, University of Maryland, Baltimore, USA
| | - Susan G. Dorsey
- School of Nursing, University of Maryland, Baltimore, USA
- Program in Neuroscience, University of Maryland, Baltimore, USA
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Kress M, Hüttenhofer A, Landry M, Kuner R, Favereaux A, Greenberg D, Bednarik J, Heppenstall P, Kronenberg F, Malcangio M, Rittner H, üçeyler N, Trajanoski Z, Mouritzen P, Birklein F, Sommer C, Soreq H. microRNAs in nociceptive circuits as predictors of future clinical applications. Front Mol Neurosci 2013; 6:33. [PMID: 24151455 PMCID: PMC3798051 DOI: 10.3389/fnmol.2013.00033] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 09/24/2013] [Indexed: 01/09/2023] Open
Abstract
Neuro-immune alterations in the peripheral and central nervous system play a role in the pathophysiology of chronic pain, and non-coding RNAs - and microRNAs (miRNAs) in particular - regulate both immune and neuronal processes. Specifically, miRNAs control macromolecular complexes in neurons, glia and immune cells and regulate signals used for neuro-immune communication in the pain pathway. Therefore, miRNAs may be hypothesized as critically important master switches modulating chronic pain. In particular, understanding the concerted function of miRNA in the regulation of nociception and endogenous analgesia and defining the importance of miRNAs in the circuitries and cognitive, emotional and behavioral components involved in pain is expected to shed new light on the enigmatic pathophysiology of neuropathic pain, migraine and complex regional pain syndrome. Specific miRNAs may evolve as new druggable molecular targets for pain prevention and relief. Furthermore, predisposing miRNA expression patterns and inter-individual variations and polymorphisms in miRNAs and/or their binding sites may serve as biomarkers for pain and help to predict individual risks for certain types of pain and responsiveness to analgesic drugs. miRNA-based diagnostics are expected to develop into hands-on tools that allow better patient stratification, improved mechanism-based treatment, and targeted prevention strategies for high risk individuals.
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Affiliation(s)
- Michaela Kress
- Department of Physiology and Medical Physics, Division of Physiology, Medical University InnsbruckInnsbruck, Austria
| | | | - Marc Landry
- UMR 5297, Interdisciplinary Institute for Neuroscience, Centre National de la Recherche Scientifique, University of BordeauxBordeaux, France
| | | | - Alexandre Favereaux
- UMR 5297, Interdisciplinary Institute for Neuroscience, Centre National de la Recherche Scientifique, University of BordeauxBordeaux, France
| | | | | | | | | | | | | | | | | | | | | | | | - Hermona Soreq
- Laboratory of Molecular Neuroscience, Department of Biological chemistry, Hebrew University of JerusalemJerusalem, Israel
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Dawes JM, McMahon SB. Chemokines as peripheral pain mediators. Neurosci Lett 2013; 557 Pt A:1-8. [PMID: 24120432 DOI: 10.1016/j.neulet.2013.10.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 09/25/2013] [Accepted: 10/01/2013] [Indexed: 11/30/2022]
Abstract
Multiple lines of evidence support the notion that much if not most chronic pain is dependent on on-going peripheral activity in nociceptors. This is not to say that central changes are unimportant, only that much of the central change is supported by a peripheral drive. This begs the question of what causes this peripheral drive. In some instances, particularly in association with peripheral nerve injury, nociceptors may become spontaneously active because of alterations in ion channel function or expression. But in most cases nociceptor activity arises because of the actions of peripheral mediators released by injured or damaged tissue. Some of these mediators are well known, such as the prostanoids. Others have more recently been identified, such as nerve growth factor (NGF). However, the limited efficacy of existing analgesic therapies strongly suggests that other important pain mediators exist. Here we discuss the evidence that a family of secreted proteins, the chemokines - well known for their actions in regulating immune cell migration - also play an important role in sustaining abnormal nociceptor activity in persistent pain states.
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Affiliation(s)
- John M Dawes
- Nuffield Department of Clinical Neurosciences, West Wing, Level 6, John Radcliffe Hospital, Oxford OX3 9DU, UK.
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Gallagher JJ, Tajerian M, Guo T, Shi X, Li W, Zheng M, Peltz G, Kingery WS, Clark JD. Acute and chronic phases of complex regional pain syndrome in mice are accompanied by distinct transcriptional changes in the spinal cord. Mol Pain 2013; 9:40. [PMID: 23924076 PMCID: PMC3751593 DOI: 10.1186/1744-8069-9-40] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 08/06/2013] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND CRPS is a painful, debilitating, and often-chronic condition characterized by various sensory, motor, and vascular disturbances. Despite many years of study, current treatments are limited by our understanding of the underlying mechanisms. Little is known on the molecular level concerning changes in gene expression supporting the nociceptive sensitization commonly observed in CRPS limbs, or how those changes might evolve over time. RESULTS We used a well-characterized mouse tibial fracture/cast immobilization model of CRPS to study molecular, vascular and nociceptive changes. We observed that the acute (3 weeks after fracture) and chronic (7 weeks after fracture) phases of CRPS-like changes in our model were accompanied by unique alterations in spinal gene expression corresponding to distinct canonical pathways. For the acute phase, top regulated pathways were: chemokine signaling, glycogen degradation, and cAMP-mediated signaling; while for the chronic phase, the associated pathways were: coagulation system, granzyme A signaling, and aryl hydrocarbon receptor signaling. We then focused on the role of CcL2, a chemokine that we showed to be upregulated at the mRNA and protein levels in spinal cord tissue in our model. We confirmed its association with the nociceptive sensitization displayed in this model by demonstrating that the spinal but not peripheral administration of a CCR2 antagonist (RS504393) in CRPS animals could decrease mechanical allodynia. The spinal administration of CcL2 itself resulted in mechanical allodynia in control mice. CONCLUSIONS Our data provide a global look at the transcriptional changes in the spinal cord that accompany the acute and chronic phases of CRPS as modeled in mice. Furthermore, it follows up on one of the top-regulated genes coding for CcL2 and validates its role in regulating nociception in the fracture/cast model of CRPS.
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Rahn EJ, Guzman-Karlsson MC, David Sweatt J. Cellular, molecular, and epigenetic mechanisms in non-associative conditioning: implications for pain and memory. Neurobiol Learn Mem 2013; 105:133-50. [PMID: 23796633 DOI: 10.1016/j.nlm.2013.06.008] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 06/10/2013] [Accepted: 06/11/2013] [Indexed: 01/09/2023]
Abstract
Sensitization is a form of non-associative conditioning in which amplification of behavioral responses can occur following presentation of an aversive or noxious stimulus. Understanding the cellular and molecular underpinnings of sensitization has been an overarching theme spanning the field of learning and memory as well as that of pain research. In this review we examine how sensitization, both in the context of learning as well as pain processing, shares evolutionarily conserved behavioral, cellular/synaptic, and epigenetic mechanisms across phyla. First, we characterize the behavioral phenomenon of sensitization both in invertebrates and vertebrates. Particular emphasis is placed on long-term sensitization (LTS) of withdrawal reflexes in Aplysia following aversive stimulation or injury, although additional invertebrate models are also covered. In the context of vertebrates, sensitization of mammalian hyperarousal in a model of post-traumatic stress disorder (PTSD), as well as mammalian models of inflammatory and neuropathic pain is characterized. Second, we investigate the cellular and synaptic mechanisms underlying these behaviors. We focus our discussion on serotonin-mediated long-term facilitation (LTF) and axotomy-mediated long-term hyperexcitability (LTH) in reduced Aplysia systems, as well as mammalian spinal plasticity mechanisms of central sensitization. Third, we explore recent evidence implicating epigenetic mechanisms in learning- and pain-related sensitization. This review illustrates the fundamental and functional overlay of the learning and memory field with the pain field which argues for homologous persistent plasticity mechanisms in response to sensitizing stimuli or injury across phyla.
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Affiliation(s)
- Elizabeth J Rahn
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
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128
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Tétreault P, Beaudet N, Perron A, Belleville K, René A, Cavelier F, Martinez J, Stroh T, Jacobi AM, Rose SD, Behlke MA, Sarret P. Spinal NTS2 receptor activation reverses signs of neuropathic pain. FASEB J 2013; 27:3741-52. [DOI: 10.1096/fj.12-225540] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Pascal Tétreault
- Department of Physiology and BiophysicsFaculty of Medicine and Health SciencesUniversité de SherbrookeSherbrookeQuébecCanada
| | - Nicolas Beaudet
- Department of Physiology and BiophysicsFaculty of Medicine and Health SciencesUniversité de SherbrookeSherbrookeQuébecCanada
| | - Amélie Perron
- Institute for Integrated Cell‐Material SciencesKyoto UniversityKyotoJapan
| | - Karine Belleville
- Department of Physiology and BiophysicsFaculty of Medicine and Health SciencesUniversité de SherbrookeSherbrookeQuébecCanada
| | - Adeline René
- Institut des Biomolécules Max MousseronUnité Mixte de Recherche‐Centre National de la Recherche Scientifique (UMR‐CNRS)‐5247Universités Montpellier I and IIMontpellierFrance
| | - Florine Cavelier
- Institut des Biomolécules Max MousseronUnité Mixte de Recherche‐Centre National de la Recherche Scientifique (UMR‐CNRS)‐5247Universités Montpellier I and IIMontpellierFrance
| | - Jean Martinez
- Institut des Biomolécules Max MousseronUnité Mixte de Recherche‐Centre National de la Recherche Scientifique (UMR‐CNRS)‐5247Universités Montpellier I and IIMontpellierFrance
| | - Thomas Stroh
- Department of Neurology and NeurosurgeryMontreal Neurological InstituteMcGill UniversityMontréalQuébecCanada
| | | | | | | | - Philippe Sarret
- Department of Physiology and BiophysicsFaculty of Medicine and Health SciencesUniversité de SherbrookeSherbrookeQuébecCanada
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Zhang H, Boyette-Davis JA, Kosturakis AK, Li Y, Yoon SY, Walters ET, Dougherty PM. Induction of monocyte chemoattractant protein-1 (MCP-1) and its receptor CCR2 in primary sensory neurons contributes to paclitaxel-induced peripheral neuropathy. THE JOURNAL OF PAIN 2013; 14:1031-44. [PMID: 23726937 DOI: 10.1016/j.jpain.2013.03.012] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/23/2012] [Revised: 01/15/2013] [Accepted: 03/05/2013] [Indexed: 01/14/2023]
Abstract
UNLABELLED The use of paclitaxel (Taxol), a microtubule stabilizer, for cancer treatment is often limited by its associated peripheral neuropathy (chemotherapy-induced peripheral neuropathy [CIPN]), which predominantly results in sensory dysfunction, including chronic pain. Here we show that paclitaxel CIPN was associated with induction of chemokine monocyte chemoattractant protein-1 (MCP-1) and its cognate receptor CCR2 in primary sensory neurons of dorsal root ganglia. Immunostaining revealed that MCP-1 was mainly expressed in small nociceptive neurons whereas CCR2 was expressed in large and medium-sized myelinated neurons. Direct application of MCP-1 consistently induced intracellular calcium increases in dorsal root ganglia large and medium-sized neurons but not in small neurons mainly dissociated from paclitaxel-treated but not vehicle-treated animals. Paclitaxel also induced increased expression of MCP-1 in spinal astrocytes, but no CCR2 signal was detected in the spinal cord. Local blockade of MCP-1/CCR2 signaling by anti-MCP-1 antibody or CCR2 antisense oligodeoxynucleotides significantly attenuated paclitaxel CIPN phenotypes including mechanical hypersensitivity and loss of intraepidermal nerve fibers in hindpaw glabrous skin. These results suggest that activation of paracrine MCP-1/CCR2 signaling between dorsal root ganglion neurons plays a critical role in the development of paclitaxel CIPN, and targeting MCP-1/CCR2 signaling could be a novel therapeutic approach. PERSPECTIVE CIPN is a severe side effect accompanying paclitaxel chemotherapy and lacks effective treatments. The current study suggests that blocking MCP-1/CCR2 signaling could be a new therapeutic strategy to prevent or reverse paclitaxel CIPN. This preclinical evidence encourages future clinical evaluation of this strategy.
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Affiliation(s)
- Haijun Zhang
- Department of Anesthesia and Pain Medicine Research, The University of Texas M.D. Anderson Cancer Center, Houston, Texas.
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130
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HDAC inhibitors attenuate the development of hypersensitivity in models of neuropathic pain. Pain 2013; 154:1668-1679. [PMID: 23693161 PMCID: PMC3763368 DOI: 10.1016/j.pain.2013.05.021] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 04/23/2013] [Accepted: 05/03/2013] [Indexed: 12/20/2022]
Abstract
Histone deacetylase inhibitors (HDACIs) interfere with the epigenetic process of histone acetylation and are known to have analgesic properties in models of chronic inflammatory pain. The aim of this study was to determine whether these compounds could also affect neuropathic pain. Different class I HDACIs were delivered intrathecally into rat spinal cord in models of traumatic nerve injury and antiretroviral drug–induced peripheral neuropathy (stavudine, d4T). Mechanical and thermal hypersensitivity was attenuated by 40% to 50% as a result of HDACI treatment, but only if started before any insult. The drugs globally increased histone acetylation in the spinal cord, but appeared to have no measurable effects in relevant dorsal root ganglia in this treatment paradigm, suggesting that any potential mechanism should be sought in the central nervous system. Microarray analysis of dorsal cord RNA revealed the signature of the specific compound used (MS-275) and suggested that its main effect was mediated through HDAC1. Taken together, these data support a role for histone acetylation in the emergence of neuropathic pain.
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131
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Pflücke D, Hackel D, Mousa SA, Partheil A, Neumann A, Brack A, Rittner HL. The molecular link between C-C-chemokine ligand 2-induced leukocyte recruitment and hyperalgesia. THE JOURNAL OF PAIN 2013; 14:897-910. [PMID: 23683582 DOI: 10.1016/j.jpain.2013.02.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 02/17/2013] [Accepted: 02/26/2013] [Indexed: 12/27/2022]
Abstract
UNLABELLED The chemokine C-C-chemokine ligand 2 (CCL2) (formerly known as MCP, macrophage chemotactic protein) is one of the important genes upregulated in different types of pain both in animals and humans. CCL2 governs the recruitment of C-C chemokine receptor 2-expressing monocytes into inflamed tissue. In contrast to neutrophilic chemokines, intraplantar injection of CCL2 in Wistar rats recruited macrophages and neutrophils and simultaneously lowered nociceptive thresholds. CCL2-induced hyperalgesia was abolished by prior systemic leukocyte depletion by cyclophosphamide and was reconstituted by local adoptive transfer of donor macrophages but not of neutrophils. Antagonists against transient receptor potential vannilloid 1 inhibited thermal and against transient receptor potential ankyrin 1 blocked mechanical hyperalgesia. Peripheral but not central activation of cyclooxygenase-2 (Cox-2) were critical for CCL2-induced hyperalgesia. In vitro CCL2 did not directly stimulate Cox-2 expression or prostaglandin E2 formation but slightly enhanced the formation of reactive oxygen species in monocytes and macrophages. In vivo, increased immunoreactivity for 4-hydroxy-2-nonenal (4-HNE), a downstream product of reactive oxygen species and known inducer of Cox-2, was observed and colocalized with Cox-2 in ED1 (CD68) positive infiltrating cells. No hyperalgesia, 4-HNE, or Cox-2 immunoreactivity was seen in leukocyte-depleted rats that were reconstituted with macrophages in the absence of CCL2, supporting the important role of CCL2. PERSPECTIVE CCL2 plays a dual role: 1) promoting monocyte/macrophage recruitment into tissue; and 2) potentially stimulating macrophages in the tissue to produce 4-HNE and subsequently Cox-2, all resulting in the induction of hyperalgesia via transient receptor potential vannilloid 1 and transient receptor potential ankyrin 1. This encourages pharmacological efforts targeting CCL2/C-C chemokine receptor 2 and macrophages for treatment of inflammatory pain.
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Affiliation(s)
- Diana Pflücke
- Department of Anesthesiology, University Hospital of Würzburg, Würzburg, Germany
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132
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The connection of monocytes and reactive oxygen species in pain. PLoS One 2013; 8:e63564. [PMID: 23658840 PMCID: PMC3642180 DOI: 10.1371/journal.pone.0063564] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 04/02/2013] [Indexed: 12/21/2022] Open
Abstract
The interplay of specific leukocyte subpopulations, resident cells and proalgesic mediators results in pain in inflammation. Proalgesic mediators like reactive oxygen species (ROS) and downstream products elicit pain by stimulation of transient receptor potential (TRP) channels. The contribution of leukocyte subpopulations however is less clear. Local injection of neutrophilic chemokines elicits neutrophil recruitment but no hyperalgesia in rats. In meta-analyses the monocytic chemoattractant, CCL2 (monocyte chemoattractant protein-1; MCP-1), was identified as an important factor in the pathophysiology of human and animal pain. In this study, intraplantar injection of CCL2 elicited thermal and mechanical pain in Wistar but not in Dark Agouti (DA) rats, which lack p47phox, a part of the NADPH oxidase complex. Inflammatory hyperalgesia after complete Freund's adjuvant (CFA) as well as capsaicin-induced hyperalgesia and capsaicin-induced current flow in dorsal root ganglion neurons in DA were comparable to Wistar rats. Macrophages from DA expressed lower levels of CCR2 and thereby migrated less towards CCL2 and formed limited amounts of ROS in vitro and 4-hydroxynonenal (4-HNE) in the tissue in response to CCL2 compared to Wistar rats. Local adoptive transfer of peritoneal macrophages from Wistar but not from DA rats reconstituted CCL2-triggered hyperalgesia in leukocyte-depleted DA and Wistar rats. A pharmacological stimulator of ROS production (phytol) restored CCL2-induced hyperalgesia in vivo in DA rats. In Wistar rats, CCL2-induced hyperalgesia was completely blocked by superoxide dismutase (SOD), catalase or tempol. Likewise, inhibition of NADPH oxidase by apocynin reduced CCL2-elicited hyperalgesia but not CFA-induced inflammatory hyperalgesia. In summary, we provide a link between CCL2, CCR2 expression on macrophages, NADPH oxidase, ROS and the development CCL2-triggered hyperalgesia, which is different from CFA-induced hyperalgesia. The study further supports the impact of CCL2 and ROS as potential targets in pain therapy.
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133
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Seo S, Grzenda A, Lomberk G, Ou XM, Cruciani RA, Urrutia R. Epigenetics: a promising paradigm for better understanding and managing pain. THE JOURNAL OF PAIN 2013; 14:549-57. [PMID: 23602266 DOI: 10.1016/j.jpain.2013.01.772] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2012] [Revised: 12/05/2012] [Accepted: 01/11/2013] [Indexed: 12/26/2022]
Abstract
UNLABELLED Epigenetic regulation of gene expression is a rapidly growing area of research. Considering the longevity and plasticity of neurons, the studies on epigenetic pathways in the nervous system should be of special interest for both epigeneticists and neuroscientists. Activation or inactivation of different epigenetic pathways becomes more pronounced when the cells experience rapid changes in their environment, and such changes can be easily caused by injury and inflammation, resulting in pain perception or distortion of pain perception (eg, hyperalgesia). Therefore, in this regard, the field of pain is at an advantage to study the epigenetic pathways. More importantly, understanding pain from an epigenetics point of view would provide a new paradigm for developing drugs or strategies for pain management. In this review, we introduce basic concepts of epigenetics, including chromatin dynamics, histone modifications, DNA methylation, and RNA-induced gene silencing. In addition, we provide evidence from published studies suggesting wide implication of different epigenetic pathways within pain pathways. PERSPECTIVE This article provides a brief overview of epigenetic pathways for gene regulation and highlights their involvement in pain. Our goal is to expose the readers to these concepts so that pain-related phenotypes can be investigated from the epigenetic point of view.
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Affiliation(s)
- Seungmae Seo
- Laboratory of Epigenetics and Chromatin Dynamics, Translational Epigenomic Program, Center for Individualized Medicine, GIH Division, Department of Medicine, Physiology, Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
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134
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Sorge RE, LaCroix-Fralish ML, Tuttle AH, Khoutorsky A, Sotocinal SG, Austin JS, Melmed K, Labialle S, Schmidt JV, Wood JN, Naumova AK, Mogil JS. The Yin and Yang of pain: variability in formalin test nociception and morphine analgesia produced by the Yin Yang 1 transcription factor gene. GENES BRAIN AND BEHAVIOR 2013; 12:405-13. [DOI: 10.1111/gbb.12030] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 02/17/2013] [Indexed: 12/20/2022]
Affiliation(s)
| | | | | | | | | | | | | | | | - J. V. Schmidt
- Department of Obstetrics and Gynecology; McGill University; Montreal; Canada
| | - J. N. Wood
- Molecular Nociception Group; University College London; London; UK
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135
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Sensory neuron downregulation of the Kv9.1 potassium channel subunit mediates neuropathic pain following nerve injury. J Neurosci 2013. [PMID: 23197740 DOI: 10.1523/jneurosci.3561-12.2012] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Chronic neuropathic pain affects millions of individuals worldwide, is typically long-lasting, and remains poorly treated with existing therapies. Neuropathic pain arising from peripheral nerve lesions is known to be dependent on the emergence of spontaneous and evoked hyperexcitability in damaged nerves. Here, we report that the potassium channel subunit Kv9.1 is expressed in myelinated sensory neurons, but is absent from small unmyelinated neurons. Kv9.1 expression was strongly and rapidly downregulated following axotomy, with a time course that matches the development of spontaneous activity and pain hypersensitivity in animal models. Interestingly, siRNA-mediated knock-down of Kv9.1 in naive rats led to neuropathic pain behaviors. Diminished Kv9.1 function also augmented myelinated sensory neuron excitability, manifested as spontaneous firing, hyper-responsiveness to stimulation, and persistent after-discharge. Intracellular recordings from ex vivo dorsal root ganglion preparations revealed that Kv9.1 knock-down was linked to lowered firing thresholds and increased firing rates under physiologically relevant conditions of extracellular potassium accumulation during prolonged activity. Similar neurophysiological changes were detected in animals subjected to traumatic nerve injury and provide an explanation for neuropathic pain symptoms, including poorly understood conditions such as hyperpathia and paresthesias. In summary, our results demonstrate that Kv9.1 dysfunction leads to spontaneous and evoked neuronal hyperexcitability in myelinated fibers, coupled with development of neuropathic pain behaviors.
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136
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Abstract
Chronic pain affects approximately one in five adults, resulting in a greatly reduced quality of life and a higher risk of developing co-morbidities such as depression. Available treatments often provide inadequate pain relief, but it is hoped that through deeper understanding of the molecular mechanisms underlying chronic pain states we can discover new and improved therapies. Although genetic research has flourished over the past decade and has identified many key genes in pain processing, the budding field of epigenetics promises to provide new insights and a more dynamic view of pain regulation. This review gives an overview of basic mechanisms and current therapies to treat pain, and discusses the clinical and preclinical evidence for the contribution of genetic and epigenetic factors, with a focus on how this knowledge can affect drug development.
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Affiliation(s)
- Megan Crow
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, UK
| | - Franziska Denk
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, UK
| | - Stephen B McMahon
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, UK
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137
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Neuro-genetics of persistent pain. Curr Opin Neurobiol 2013; 23:127-32. [DOI: 10.1016/j.conb.2012.11.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 11/14/2012] [Accepted: 11/19/2012] [Indexed: 11/20/2022]
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138
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Ueda H, Matsunaga H, Olaposi OI, Nagai J. Lysophosphatidic acid: Chemical signature of neuropathic pain. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:61-73. [DOI: 10.1016/j.bbalip.2012.08.014] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 08/21/2012] [Accepted: 08/21/2012] [Indexed: 02/07/2023]
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139
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Williams FMK, Scollen S, Cao D, Memari Y, Hyde CL, Zhang B, Sidders B, Ziemek D, Shi Y, Harris J, Harrow I, Dougherty B, Malarstig A, McEwen R, Stephens JC, Patel K, Menni C, Shin SY, Hodgkiss D, Surdulescu G, He W, Jin X, McMahon SB, Soranzo N, John S, Wang J, Spector TD. Genes contributing to pain sensitivity in the normal population: an exome sequencing study. PLoS Genet 2012; 8:e1003095. [PMID: 23284290 PMCID: PMC3527205 DOI: 10.1371/journal.pgen.1003095] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 10/01/2012] [Indexed: 12/02/2022] Open
Abstract
Sensitivity to pain varies considerably between individuals and is known to be heritable. Increased sensitivity to experimental pain is a risk factor for developing chronic pain, a common and debilitating but poorly understood symptom. To understand mechanisms underlying pain sensitivity and to search for rare gene variants (MAF<5%) influencing pain sensitivity, we explored the genetic variation in individuals' responses to experimental pain. Quantitative sensory testing to heat pain was performed in 2,500 volunteers from TwinsUK (TUK): exome sequencing to a depth of 70× was carried out on DNA from singletons at the high and low ends of the heat pain sensitivity distribution in two separate subsamples. Thus in TUK1, 101 pain-sensitive and 102 pain-insensitive were examined, while in TUK2 there were 114 and 96 individuals respectively. A combination of methods was used to test the association between rare variants and pain sensitivity, and the function of the genes identified was explored using network analysis. Using causal reasoning analysis on the genes with different patterns of SNVs by pain sensitivity status, we observed a significant enrichment of variants in genes of the angiotensin pathway (Bonferroni corrected p = 3.8×10−4). This pathway is already implicated in animal models and human studies of pain, supporting the notion that it may provide fruitful new targets in pain management. The approach of sequencing extreme exome variation in normal individuals has provided important insights into gene networks mediating pain sensitivity in humans and will be applicable to other common complex traits. Chronic widespread pain is a complex clinical problem. Identification of underlying genetic factors would shed light on the biology of pain and offer targets for novel therapies. We aimed to identify rare genetic variants in the normal population associated with pain sensation by performing exome sequencing on individuals who were more or less sensitive to heat pain. While we did not identify any single variants having large effect, we did observe major group differences between the sensitive and insensitive individuals. Network analysis suggested a role for the angiotensin pathway, which previous work in animal models has suggested is important in pain mediation. Our results cast light on the genetic factors underlying normal pain sensation in humans and the utility of exome analyses. It suggests that further exploration of the angiotensin pathway may reveal novel targets for the treatment of pain.
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Affiliation(s)
- Frances M. K. Williams
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
| | - Serena Scollen
- Pfizer Limited, Neusentis, Granta Park, Cambridge, United Kingdom
| | | | - Yasin Memari
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, United Kingdom
| | - Craig L. Hyde
- Pfizer Research Laboratories, Groton, Connecticut, United States of America
| | - Baohong Zhang
- Pfizer Research Laboratories, Groton, Connecticut, United States of America
| | - Benjamin Sidders
- Pfizer Limited, Neusentis, Granta Park, Cambridge, United Kingdom
| | - Daniel Ziemek
- Worldwide R&D, Pfizer, Cambridge, Massachusetts, United States of America
| | | | - Juliette Harris
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
| | - Ian Harrow
- Pfizer Global Research and Development, Sandwich, United Kingdom
| | - Brian Dougherty
- Pfizer Research Laboratories, Groton, Connecticut, United States of America
| | - Anders Malarstig
- Pfizer Limited, Neusentis, Granta Park, Cambridge, United Kingdom
| | - Robert McEwen
- Pfizer Global Research and Development, Sandwich, United Kingdom
| | - Joel C. Stephens
- Pfizer Research Laboratories, Groton, Connecticut, United States of America
| | - Ketan Patel
- Pfizer Global Research and Development, Sandwich, United Kingdom
| | - Cristina Menni
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
| | - So-Youn Shin
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, United Kingdom
| | - Dylan Hodgkiss
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
| | - Gabriela Surdulescu
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
| | - Wen He
- Pfizer Research Laboratories, Groton, Connecticut, United States of America
| | - Xin Jin
- BGI–Shenzhen, Shenzhen, China
- School of Bioscience and Biotechnology, South China University of Technology, Guangzhou, China
| | | | - Nicole Soranzo
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, United Kingdom
| | - Sally John
- Pfizer Research Laboratories, Groton, Connecticut, United States of America
| | - Jun Wang
- BGI–Shenzhen, Shenzhen, China
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
- * E-mail: (JW); (TDS)
| | - Tim D. Spector
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
- * E-mail: (JW); (TDS)
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140
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Antunes-Martins A, Perkins JR, Lees J, Hildebrandt T, Orengo C, Bennett DLH. Systems biology approaches to finding novel pain mediators. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2012; 5:11-35. [PMID: 23059966 DOI: 10.1002/wsbm.1192] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Chronic pain represents a major health burden; this maladaptive pain state occurs as a consequence of hypersensitivity within the peripheral and central components of the somatosensory system. High throughput technologies (genomics, transciptomics, lipidomics, and proteomics) are now being applied to tissue derived from pain patients as well as experimental pain models to discover novel pain mediators. The use of clustering, meta-analysis and other techniques can help refine potential candidates. Of particular importance are systems biology methods, such as co-expression network generating algorithms, which infer potential associations/interactions between molecules and build networks based on these interactions. Protein-protein interaction networks allow the lists of potential targets generated by these different platforms to be analyzed in their biological context. Outputs from these different methods must also be related to the clinical pain phenotype. The improved and standardized phenotyping of pain symptoms and sensory signs enables much better subject stratification. Our hope is that, in the future, the use of computational approaches to integrate datasets including sensory phenotype as well as the outputs of high throughput technologies will help define novel pain mediators and provide insights into the pathogenesis of chronic pain.
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Affiliation(s)
- Ana Antunes-Martins
- The Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London, UK
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141
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Smith MT, Muralidharan A. Pharmacogenetics of pain and analgesia. Clin Genet 2012; 82:321-30. [PMID: 22779698 DOI: 10.1111/j.1399-0004.2012.01936.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 07/08/2012] [Accepted: 07/08/2012] [Indexed: 12/19/2022]
Abstract
Pain severity ratings and the analgesic dosing requirements of patients with apparently similar pain conditions may differ considerably between individuals. Contributing factors include those of genetic and environmental origin with epigenetic mechanisms that enable dynamic gene-environment interaction, more recently implicated in pain modulation. Insight into genetic factors underpinning inter-patient variability in pain sensitivity has come from rodent heritability studies as well as familial aggregation and twin studies in humans. Indeed, more than 350 candidate pain genes have been identified as potentially contributing to heritable differences in pain sensitivity. A large number of genetic association studies conducted in patients with a variety of clinical pain types or in humans exposed to experimentally induced pain stimuli in the laboratory setting, have examined the impact of single-nucleotide polymorphisms in various target genes on pain sensitivity and/or analgesic dosing requirements. However, the findings of such studies have generally failed to replicate or have been only partially replicated by independent investigators. Deficiencies in study conduct including use of small sample size, inappropriate statistical methods and inadequate attention to the possibility that between-study differences in environmental factors may alter pain phenotypes through epigenetic mechanisms, have been identified as being significant.
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Affiliation(s)
- M T Smith
- Centre for Integrated Preclinical Drug Development, The University of Queensland, Brisbane, Queensland, Australia.
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142
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Gerhardt A, Hartmann M, Tesarz J, Janke S, Leisner S, Seidler G, Eich W. Subgroups of musculoskeletal pain patients and their psychobiological patterns - the LOGIN study protocol. BMC Musculoskelet Disord 2012; 13:136. [PMID: 22862787 PMCID: PMC3476389 DOI: 10.1186/1471-2474-13-136] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 07/23/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pain conditions of the musculoskeletal system are very common and have tremendous socioeconomic impact. Despite its high prevalence, musculoskeletal pain remains poorly understood and predominantly non-specifically and insufficiently treated.The group of chronic musculoskeletal pain patients is supposed to be heterogeneous, due to a multitude of mechanisms involved in chronic pain. Psychological variables, psychophysiological processes, and neuroendocrine alterations are expected to be involved. Thus far, studies on musculoskeletal pain have predominantly focused on the general aspects of pain processing, thus neglecting the heterogeneity of patients with musculoskeletal pain. Consequently, there is a need for studies that comprise a multitude of mechanisms that are potentially involved in the chronicity and spread of pain. This need might foster research and facilitate a better pathophysiological understanding of the condition, thereby promoting the development of specific mechanism-based treatments for chronic pain. Therefore, the objectives of this study are as follows: 1) identify and describe subgroups of patients with musculoskeletal pain with regard to clinical manifestations (including mental co-morbidity) and 2) investigate whether distinct sensory profiles or 3) distinct plasma levels of pain-related parameters due to different underlying mechanisms can be distinguished in various subgroups of pain patients. METHODS/DESIGN We will examine a population-based chronic pain sample (n = 100), a clinical tertiary care sample (n = 100) and pain-free patients with depression or post-traumatic stress disorder and pain-free healthy controls (each n = 30, respectively). The samples will be pain localisation matched by sex and age to the population-based sample. Patients will undergo physical examination and thorough assessments of mental co-morbidity (including psychological trauma), perceptual and central sensitisation (quantitative sensory testing), descending inhibition (conditioned pain modulation, the diffuse noxious inhibitory control-like effect), as well as measurement of the plasma levels of nerve growth factor and endocannabinoids. DISCUSSION The identification of the underlying pathophysiologic mechanisms in different subgroups of chronic musculoskeletal pain patients will contribute to a mechanism-based subgroup classification. This will foster the development of mechanism-based treatments and holds promise to treat patients more sufficient.
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Affiliation(s)
- Andreas Gerhardt
- Department of General Internal Medicine and Psychosomatics, University Hospital Heidelberg, Heidelberg, Germany.
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Strong JA, Xie W, Coyle DE, Zhang JM. Microarray analysis of rat sensory ganglia after local inflammation implicates novel cytokines in pain. PLoS One 2012; 7:e40779. [PMID: 22815815 PMCID: PMC3397953 DOI: 10.1371/journal.pone.0040779] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 06/13/2012] [Indexed: 01/15/2023] Open
Abstract
Inflammation plays a role in neuropathic pain conditions as well as in pain induced solely by an inflammatory stimulus. Robust mechanical hyperalgesia and allodynia can be induced by locally inflaming the L5 dorsal root ganglion (DRG) in rat. This model allows investigation of the contribution of inflammation per se to chronic pain conditions. Most previous microarray studies of DRG gene expression have investigated neuropathic pain models. To examine the role of inflammation, we used microarray methods to examine gene expression 3 days after local inflammation of the L5 DRG in rat. We observed significant regulation in a large number of genes (23% of observed transcripts), and examined 221 (3%) with a fold-change of 1.5-fold or more in more detail. Immune-related genes were the largest category in this group and included members of the complement system as well as several pro-inflammatory cytokines. However, these upregulated cytokines had no prior links to peripheral pain in the literature other than through microarray studies, though most had previously described roles in CNS (especially neuroinflammatory conditions) as well as in immune responses. To confirm an association to pain, qPCR studies examined these cytokines at a later time (day 14), as well as in two different versions of the spinal nerve ligation pain model including a version without any foreign immunogenic material (suture). Cxcl11, Cxcl13, and Cxcl14 were found to be significantly upregulated in all these conditions, while Cxcl9, Cxcl10, and Cxcl16 were upregulated in at least two of these conditions.
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Affiliation(s)
- Judith A. Strong
- Department of Anesthesiology, Pain Research Center, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- * E-mail: (JAS); (J-MZ)
| | - Wenrui Xie
- Department of Anesthesiology, Pain Research Center, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Dennis E. Coyle
- Department of Anesthesiology, Pain Research Center, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Jun-Ming Zhang
- Department of Anesthesiology, Pain Research Center, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- * E-mail: (JAS); (J-MZ)
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Grace PM, Hurley D, Barratt DT, Tsykin A, Watkins LR, Rolan PE, Hutchinson MR. Harnessing pain heterogeneity and RNA transcriptome to identify blood-based pain biomarkers: a novel correlational study design and bioinformatics approach in a graded chronic constriction injury model. J Neurochem 2012; 122:976-94. [PMID: 22697386 DOI: 10.1111/j.1471-4159.2012.07833.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A quantitative, peripherally accessible biomarker for neuropathic pain has great potential to improve clinical outcomes. Based on the premise that peripheral and central immunity contribute to neuropathic pain mechanisms, we hypothesized that biomarkers could be identified from the whole blood of adult male rats, by integrating graded chronic constriction injury (CCI), ipsilateral lumbar dorsal quadrant (iLDQ) and whole blood transcriptomes, and pathway analysis with pain behavior. Correlational bioinformatics identified a range of putative biomarker genes for allodynia intensity, many encoding for proteins with a recognized role in immune/nociceptive mechanisms. A selection of these genes was validated in a separate replication study. Pathway analysis of the iLDQ transcriptome identified Fcγ and Fcε signaling pathways, among others. This study is the first to employ the whole blood transcriptome to identify pain biomarker panels. The novel correlational bioinformatics, developed here, selected such putative biomarkers based on a correlation with pain behavior and formation of signaling pathways with iLDQ genes. Future studies may demonstrate the predictive ability of these biomarker genes across other models and additional variables.
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Affiliation(s)
- Peter M Grace
- Discipline of Pharmacology, School of Medical Sciences, University of Adelaide, Adelaide, Australia.
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Rogoz K, Lagerström MC, Dufour S, Kullander K. VGLUT2-dependent glutamatergic transmission in primary afferents is required for intact nociception in both acute and persistent pain modalities. Pain 2012; 153:1525-1536. [DOI: 10.1016/j.pain.2012.04.017] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 03/29/2012] [Accepted: 04/17/2012] [Indexed: 11/27/2022]
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146
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Spofford CM, Brennan TJ. Gene expression in skin, muscle, and dorsal root ganglion after plantar incision in the rat. Anesthesiology 2012; 117:161-72. [PMID: 22617252 PMCID: PMC3389501 DOI: 10.1097/aln.0b013e31825a2a2b] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND Treating postoperative pain remains a significant challenge for perioperative medicine. Recent studies have shown that nerve growth factor is up-regulated and contributes to incisional pain. To date, few studies have examined expression of other neurotrophin-related mediators that may contribute to the development and/or maintenance of incisional pain. METHODS Male Sprague-Dawley rats underwent a plantar incision, and pain behaviors were examined (n = 6). In a separate group of rats, expression of neurotrophic factors were studied. At various times after incision (n = 4) or sham surgery (n = 4), the skin, muscle, and dorsal root ganglia were harvested and total RNA isolated. Real-time reverse transcription polymerase chain reaction was performed and the fold change in gene expression was analyzed using significance analysis of microarrays. RESULTS Several genes were changed (P < 0.05) as early as 1 h after incision. Expression of artemin and nerve growth factor were increased in both incised skin and muscle. Brain-derived neurotrophic factor, neurotrophin-3, and neurotrophin-5 were all down-regulated in the skin but up-regulated in the muscle 48 h after incision. Few genes changed in the dorsal root ganglion. Most changes in expression occurred in the first 48 h after incision, a timeframe when pain behavior was the greatest. CONCLUSION Surgical incision is associated with pain-related gene expression changes in skin, muscle, and, to a lesser extent, dorsal root ganglion. The gene expression profile provides clues as to mediators that are involved in peripheral sensitization and pain transmission after surgical incision and also suggest mechanisms for resolution of postoperative pain when more persistent pain syndromes like neuropathic pain continue.
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Integrative approach to pain genetics identifies pain sensitivity loci across diseases. PLoS Comput Biol 2012; 8:e1002538. [PMID: 22685391 PMCID: PMC3369906 DOI: 10.1371/journal.pcbi.1002538] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 04/16/2012] [Indexed: 11/29/2022] Open
Abstract
Identifying human genes relevant for the processing of pain requires difficult-to-conduct and expensive large-scale clinical trials. Here, we examine a novel integrative paradigm for data-driven discovery of pain gene candidates, taking advantage of the vast amount of existing disease-related clinical literature and gene expression microarray data stored in large international repositories. First, thousands of diseases were ranked according to a disease-specific pain index (DSPI), derived from Medical Subject Heading (MESH) annotations in MEDLINE. Second, gene expression profiles of 121 of these human diseases were obtained from public sources. Third, genes with expression variation significantly correlated with DSPI across diseases were selected as candidate pain genes. Finally, selected candidate pain genes were genotyped in an independent human cohort and prospectively evaluated for significant association between variants and measures of pain sensitivity. The strongest signal was with rs4512126 (5q32, ABLIM3, P = 1.3×10−10) for the sensitivity to cold pressor pain in males, but not in females. Significant associations were also observed with rs12548828, rs7826700 and rs1075791 on 8q22.2 within NCALD (P = 1.7×10−4, 1.8×10−4, and 2.2×10−4 respectively). Our results demonstrate the utility of a novel paradigm that integrates publicly available disease-specific gene expression data with clinical data curated from MEDLINE to facilitate the discovery of pain-relevant genes. This data-derived list of pain gene candidates enables additional focused and efficient biological studies validating additional candidates. The mechanisms underlying pain are incompletely understood, and are hard to study due to the subjective and complex nature of pain. From a genetics perspective, the discovery of genes relevant for the processing of pain in humans has been slow and genome-wide association studies have not been successful in yielding significantly associated variants. Targeted approaches examining specific candidate genes may be more promising. We present a novel integrative approach that combines publicly available molecular data and automatically extracted knowledge regarding pain contained in the literature to assist the discovery of novel pain genes. We prospectively validated this approach by demonstrating a significant association between several newly identified pain gene candidates and sensitivity to cold pressor pain.
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Bubier JA, Chesler EJ. Accelerating discovery for complex neurological and behavioral disorders through systems genetics and integrative genomics in the laboratory mouse. Neurotherapeutics 2012; 9:338-48. [PMID: 22422471 PMCID: PMC3325414 DOI: 10.1007/s13311-012-0111-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Recent advances in systems genetics and integrative functional genomics have greatly improved the study of complex neurological and behavioral traits. The methods developed for the integrated characterization of new, high-resolution mouse genetic reference populations and systems genetics enable behavioral geneticists an unprecedented opportunity to address questions of the molecular basis of neurological and psychiatric disorders and their comorbidities. Integrative genomics augment these strategies by enabling rapid informatics-assisted candidate gene prioritization, cross-species translation, and mechanistic comparison across related disorders from a wealth of existing data in mouse and other model organisms. Ultimately, through these complementary approaches, finding the mechanisms and sources of genetic variation underlying complex neurobehavioral disease related traits is becoming tractable. Furthermore, these methods enable categorization of neurobehavioral disorders through their underlying biological basis. Together, these model organism-based approaches can lead to a refinement of diagnostic categories and targeted treatment of neurological and psychiatric disease.
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Mogil JS. Pain genetics: past, present and future. Trends Genet 2012; 28:258-66. [PMID: 22464640 DOI: 10.1016/j.tig.2012.02.004] [Citation(s) in RCA: 223] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 02/16/2012] [Accepted: 02/22/2012] [Indexed: 01/01/2023]
Abstract
Chronic pain is a classic example of gene × environment interaction: inflammatory and/or nerve injuries are known or suspected to be the etiology of most chronic pain syndromes, but only a small minority of those subjected to such injuries actually develop chronic pain. Once chronic pain has developed, pain severity and analgesic response are also highly variable among individuals. Although animal genetics studies have been ongoing for over two decades, only recently have comprehensive human twin studies and large-scale association studies been performed. Here, I review recent and accelerating progress in, and continuing challenges to, the identification of genes contributing to such variability. Success in this endeavor will hopefully lead to both better management of pain using currently available therapies and the development and/or prioritizing of new ones.
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Affiliation(s)
- Jeffrey S Mogil
- Department of Psychology, McGill University, Montreal, QC, H3A 1B1, Canada.
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Tochiki KK, Cunningham J, Hunt SP, Géranton SM. The expression of spinal methyl-CpG-binding protein 2, DNA methyltransferases and histone deacetylases is modulated in persistent pain states. Mol Pain 2012; 8:14. [PMID: 22369085 PMCID: PMC3351747 DOI: 10.1186/1744-8069-8-14] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Accepted: 02/27/2012] [Indexed: 12/05/2022] Open
Abstract
Background DNA CpG methylation is carried out by DNA methyltransferases and induces chromatin remodeling and gene silencing through a transcription repressor complex comprising the methyl-CpG-binding protein 2 (MeCP2) and a subset of histone deacetylases. Recently, we have found that MeCP2 activity had a crucial role in the pattern of gene expression seen in the superficial dorsal horn rapidly after injection of Complete Freund's Adjuvant (CFA) in the rat ankle joint. The aim of the present study was to analyse the changes in expression of MeCP2, DNA methyltransferases and a subset of histone deacetylases in the superficial dorsal horn during the maintenance phase of persistent pain states. In this process, the cell specific expression of MeCP2 was also investigated. Results Using immunohistochemistry, we found that neurones, oligodendrocytes and astrocytes expressed MeCP2. Microglia, oligodendrocyte precursor cells and Schwann cells never showed any positive stain for MeCP2. Quantitative analyses showed that MeCP2 expression was increased in the superficial dorsal horn 7 days following CFA injection in the ankle joint but decreased 7 days following spared nerve injury. Overall, the expression of DNA methyltransferases and a subset of histone deacetylases followed the same pattern of expression. However, there were no significant changes in the expression of the MeCP2 targets that we had previously shown are regulated in the early time points following CFA injection in the ankle joint. Finally, the expression of MeCP2 was also down regulated in damaged dorsal root ganglion neurones following spared nerve injury. Conclusion Our results strongly suggest that changes in chromatin compaction, regulated by the binding of MeCP2 complexes to methylated DNA, are involved in the modulation of gene expression in the superficial dorsal horn and dorsal root ganglia during the maintenance of persistent pain states.
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Affiliation(s)
- Keri K Tochiki
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
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