BACKGROUND: IL-6 is a typical injury-induced mediator. Together with its receptors, IL-6 contributes to both induction and maintenance of neuropathic pain deriving from changes in activity of primary sensory neurons in dorsal root ganglia (DRG). We used in situ hybridization to provide evidence of IL-6 and IL-6 receptors (IL-6R and gp130) synthesis in DRG along the neuraxis after unilateral chronic constriction injury (CCI) of the sciatic nerve as an experimental model of neuropathic pain. RESULTS: All rats operated upon to create unilateral CCI displayed mechanical allodynia and thermal hyperalgesia in ipsilateral hind paws. Contralateral hind paws and forepaws of both sides exhibited only temporal and nonsignificant changes of sensitivity. Very low levels of IL-6 and IL-6R mRNAs were detected in naïve DRG. IL-6 mRNA was bilaterally increased not only in DRG neurons but also in satellite glial cells (SGC) activated by unilateral CCI. In addition to IL-6 mRNA, substantial increase of IL-6R mRNA expression occurred in DRG neurons and SGC following CCI, while the level of gp130 mRNA remained similar to that of DRG from naïve rats. CONCLUSIONS: Here we evidence for the first time increased synthesis of IL-6 and IL-6R in remote cervical DRG nonassociated with the nerve injury. Our results suggest that unilateral CCI of the sciatic nerve induced not only bilateral elevation of IL-6 and IL-6R mRNAs in L4-L5 DRG but also their propagation along the neuraxis to remote cervical DRG as a general neuroinflammatory reaction of the nervous system to local nerve injury without correlation with signs of neuropathic pain. Possible functional involvement of IL-6 signaling is discussed.

• MeSH
• In Situ Hybridization MeSH
• Interleukin-6 genetics   MeSH
• Rats MeSH
• RNA, Messenger metabolism   MeSH
• Disease Models, Animal MeSH
• Sciatic Neuropathy genetics   MeSH
• Neuralgia genetics   MeSH
• Neuroglia metabolism   MeSH
• Rats, Wistar MeSH
• Receptors, Interleukin-6 genetics   MeSH
• Ganglia, Spinal metabolism   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Interleukin-6 MeSH
• RNA, Messenger MeSH
• Receptors, Interleukin-6 MeSH

Cannabinoid receptor type 2 (CB2R) plays a critical role in nociception. In contrast to cannabinoid receptor type 1 ligands, CB2R agonists do not produce undesirable central nervous system effects and thus promise to treat neuropathic pain that is often resistant to medical therapy. In the study presented here, we evaluated the bilateral distribution of the CB2R protein and messenger RNA (mRNA) in rat dorsal root ganglia (DRG) after unilateral peripheral nerve injury using immunohistochemistry, western blot, and in situ hybridization analysis. Unilateral chronic constriction injury (CCI) of the sciatic nerve induced neuropathic pain behavior and bilateral elevation of both CB2R protein and mRNA in lumbar L4-L5 as well as cervical C7-C8 DRG when compared with naive animals. CB2R protein and mRNA were increased not only in DRG neurons but also in satellite glial cells. The fact that changes appear bilaterally and (albeit at a lower level) even in the remote cervical DRG can be related to propagation of neuroinflammation alongside the neuraxis and to the neuroprotective effects of CB2R.

• Keywords
• remote neuroinflammation, satellite glial cells, unilateral nerve injury,
• MeSH
• Behavior, Animal MeSH
• Rats MeSH
• RNA, Messenger genetics   metabolism   MeSH
• Disease Models, Animal MeSH
• Sciatic Nerve injuries   MeSH
• Neuralgia genetics   metabolism   pathology   MeSH
• Rats, Wistar MeSH
• Receptor, Cannabinoid, CB2 genetics   metabolism   MeSH
• Gene Expression Regulation * MeSH
• Ganglia, Spinal metabolism   pathology   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• RNA, Messenger MeSH
• Receptor, Cannabinoid, CB2 MeSH

BACKGROUND: Current research implicates interleukin (IL)-6 as a key component of the nervous-system response to injury with various effects. METHODS: We used unilateral chronic constriction injury (CCI) of rat sciatic nerve as a model for neuropathic pain. Immunofluorescence, ELISA, western blotting and in situ hybridization were used to investigate bilateral changes in IL-6 protein and mRNA in both lumbar (L4-L5) and cervical (C7-C8) dorsal root ganglia (DRG) following CCI. The operated (CCI) and sham-operated (sham) rats were assessed after 1, 3, 7, and 14 days. Withdrawal thresholds for mechanical hyperalgesia and latencies for thermal hyperalgesia were measured in both ipsilateral and contralateral hind and fore paws. RESULTS: The ipsilateral hind paws of all CCI rats displayed a decreased threshold of mechanical hyperalgesia and withdrawal latency of thermal hyperalgesia, while the contralateral hind and fore paws of both sides exhibited no significant changes in mechanical or thermal sensitivity. No significant behavioral changes were found in the hind and fore paws on either side of the sham rats, except for thermal hypersensitivity, which was present bilaterally at 3 days. Unilateral CCI of the sciatic nerve induced a bilateral increase in IL-6 immunostaining in the neuronal bodies and satellite glial cells (SGC) surrounding neurons of both lumbar and cervical DRG, compared with those of naive control rats. This bilateral increase in IL-6 protein levels was confirmed by ELISA and western blotting. More intense staining for IL-6 mRNA was detected in lumbar and cervical DRG from both sides of rats following CCI. The DRG removed from sham rats displayed a similar pattern of staining for IL-6 protein and mRNA as found in naive DRG, but there was a higher staining intensity in SGC. CONCLUSIONS: Bilateral elevation of IL-6 protein and mRNA is not limited to DRG homonymous to the injured nerve, but also extended to DRG that are heteronymous to the injured nerve. The results for IL-6 suggest that the neuroinflammatory reaction of DRG to nerve injury is propagated alongside the neuroaxis from the lumbar to the remote cervical segments. This is probably related to conditioning of cervical DRG neurons to injury.

• MeSH
• Enzyme-Linked Immunosorbent Assay MeSH
• Functional Laterality physiology   MeSH
• Physical Stimulation MeSH
• In Situ Hybridization MeSH
• Hyperalgesia metabolism   MeSH
• Immunohistochemistry MeSH
• Interleukin-6 biosynthesis   genetics   MeSH
• Cervical Vertebrae MeSH
• Rats MeSH
• Lumbosacral Region MeSH
• Pain Measurement MeSH
• RNA, Messenger biosynthesis   genetics   MeSH
• Sciatic Neuropathy metabolism   MeSH
• Neuralgia metabolism   MeSH
• Image Processing, Computer-Assisted MeSH
• Rats, Wistar MeSH
• Receptors, Interleukin-6 biosynthesis   genetics   MeSH
• Ganglia, Spinal metabolism   MeSH
• Constriction, Pathologic MeSH
• Nerve Compression Syndromes metabolism   MeSH
• Hot Temperature MeSH
• Blotting, Western MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Interleukin-6 MeSH
• RNA, Messenger MeSH
• Receptors, Interleukin-6 MeSH

Embryonic stem cells (ESCs) maintain their pluripotency through high expression of pluripotency-related genes. Here, we show that differing levels of Oct4, Nanog, and c-myc proteins among the individual cells of mouse ESC (mESC) colonies and fluctuations in these levels do not disturb mESC pluripotency. Cells with strong expression of Oct4 had low levels of Nanog and c-myc proteins and vice versa. In addition, cells with high levels of Nanog tended to occupy interior regions of mESC colonies. In contrast, peripherally positioned cells within colonies had dense H3K27-trimethylation, especially at the nuclear periphery. We also observed distinct levels of endogenous and exogenous Oct4 in particular cell cycle phases. The highest levels of Oct4 occurred in G2 phase, which correlated with the pKi-67 nuclear pattern. Moreover, the Oct4 protein resided on mitotic chromosomes. We suggest that there must be an endogenous mechanism that prevents the induction of spontaneous differentiation, despite fluctuations in protein levels within an mESC colony. Based on the results presented here, it is likely that cells within a colony support each other in the maintenance of pluripotency.

• MeSH
• Ki-67 Antigen metabolism   MeSH
• Cell Differentiation * MeSH
• Cell Nucleus genetics   metabolism   MeSH
• Embryonic Stem Cells cytology   metabolism   MeSH
• Epigenesis, Genetic MeSH
• Fluorescence Recovery After Photobleaching MeSH
• G2 Phase MeSH
• Histones metabolism   MeSH
• Homeodomain Proteins genetics   metabolism   MeSH
• Microscopy, Confocal MeSH
• Cells, Cultured MeSH
• Lysine metabolism   MeSH
• Methylation MeSH
• Mice MeSH
• Nanog Homeobox Protein MeSH
• Stem Cell Niche MeSH
• Octamer Transcription Factor-3 genetics   metabolism   MeSH
• Pluripotent Stem Cells cytology   metabolism   MeSH
• Proto-Oncogene Proteins c-myc genetics   metabolism   MeSH
• Blotting, Western MeSH
• Green Fluorescent Proteins genetics   metabolism   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Ki-67 Antigen MeSH
• Histones MeSH
• Homeodomain Proteins MeSH
• Lysine MeSH
• Myc protein, mouse MeSH Browser
• Nanog protein, mouse MeSH Browser
• Nanog Homeobox Protein MeSH
• Octamer Transcription Factor-3 MeSH
• Proto-Oncogene Proteins c-myc MeSH
• Green Fluorescent Proteins MeSH

The nucleolus is a nuclear compartment that plays an important role in ribosome biogenesis. Some structural features and epigenetic patterns are shared between nucleolar and non-nucleolar compartments. For example, the location of transcriptionally active mRNA on extended chromatin loop species is similar to that observed for transcriptionally active ribosomal DNA (rDNA) genes on so-called Christmas tree branches. Similarly, nucleolus organizer region-bearing chromosomes located a distance from the nucleolus extend chromatin fibers into the nucleolar compartment. Specific epigenetic events, such as histone acetylation and methylation and DNA methylation, also regulate transcription of both rRNA- and mRNA-encoding loci. Here, we review the epigenetic mechanisms and structural features that regulate transcription of ribosomal and mRNA genes. We focus on similarities in epigenetic and structural regulation of chromatin in nucleoli and the surrounding non-nucleolar region and discuss the role of proteins, such as heterochromatin protein 1, fibrillarin, nucleolin, and upstream binding factor, in rRNA synthesis and processing.

• MeSH
• Cell Nucleolus genetics   metabolism   ultrastructure   MeSH
• Chromatin genetics   ultrastructure   MeSH
• Epigenesis, Genetic * MeSH
• Transcription, Genetic MeSH
• Genes, rRNA MeSH
• Histones metabolism   MeSH
• Humans MeSH
• RNA, Messenger genetics   MeSH
• DNA, Ribosomal genetics   MeSH
• Ribosomes genetics   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Comparative Study MeSH
• Names of Substances
• Chromatin MeSH
• Histones MeSH
• RNA, Messenger MeSH
• DNA, Ribosomal MeSH

Epigenetic modifications, such as acetylation, phosphorylation, methylation, ubiquitination, and ADP ribosylation, of the highly conserved core histones, H2A, H2B, H3, and H4, influence the genetic potential of DNA. The enormous regulatory potential of histone modification is illustrated in the vast array of epigenetic markers found throughout the genome. More than the other types of histone modification, acetylation and methylation of specific lysine residues on N-terminal histone tails are fundamental for the formation of chromatin domains, such as euchromatin, and facultative and constitutive heterochromatin. In addition, the modification of histones can cause a region of chromatin to undergo nuclear compartmentalization and, as such, specific epigenetic markers are non-randomly distributed within interphase nuclei. In this review, we summarize the principles behind epigenetic compartmentalization and the functional consequences of chromatin arrangement within interphase nuclei.

• MeSH
• Acetylation MeSH
• Cell Nucleus metabolism   ultrastructure   MeSH
• Chromatin ultrastructure   MeSH
• Chromosomal Proteins, Non-Histone physiology   MeSH
• Epigenesis, Genetic MeSH
• Gene Expression MeSH
• Histones genetics   metabolism   MeSH
• Chromobox Protein Homolog 5 MeSH
• Histone Deacetylase Inhibitors MeSH
• Interphase MeSH
• Humans MeSH
• Chromosomes, Human, X metabolism   MeSH
• Methylation MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Names of Substances
• Chromatin MeSH
• Chromosomal Proteins, Non-Histone MeSH
• Histones MeSH
• Chromobox Protein Homolog 5 MeSH
• Histone Deacetylase Inhibitors MeSH

It is known that chromosomes occupy non-random positions in the cell nucleus. However, it is not clear to what extent their nuclear positions, together with their neighborhood, are conserved in daughter cells. To address specific aspects of this problem, we used the model of the chromosomes carrying ribosomal genes that are organized in clusters termed Nucleolus Organizer Regions (NORs). We compared the association of chosen NOR-bearing chromosomes (NOR-chromosomes) with nucleoli, as well as the numbers of nucleoli, in the pairs of daughter cells, and established how frequently the daughter cells had equal numbers of the homologs of certain NOR-chromosomes associated with individual nucleoli. The daughter cells typically had different numbers of nucleoli. At the same time, using immuno-FISH with probes for chromosomes 14 and 15 in HeLa cells, we found that the cell pairs with identical combinations appeared significantly more frequently than predicted by the random model. Thus, although the total number of chromosomes associated with nucleoli is variable, our data indicate that the position of the NOR-bearing chromosomes in relation to nucleoli is partly conserved through mitosis.

• MeSH
• Cell Nucleolus physiology   MeSH
• HeLa Cells MeSH
• In Situ Hybridization, Fluorescence MeSH
• Humans MeSH
• Chromosomes, Human, Pair 14 * MeSH
• Chromosomes, Human, Pair 15 * MeSH
• Mitosis genetics   MeSH
• Models, Genetic MeSH
• Nucleolus Organizer Region * MeSH
• Chromosome Positioning * MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Nuclear locations of the c-myc gene and its transcripts (c-myc (T)) have been investigated in relation to nuclear domains involved in RNA synthesis and processing. Transcription of the c-myc gene appears to be linked to the late G(1)- and preferentially to S-phases of the cell cycle. The c-myc gene and its transcripts were positioned non-randomly within the interphase nucleus; additionally, c-myc RNA signals accumulated at nucleoli. Using oligo-probes, designed to exon II and exon III of the c-myc gene, single c-myc (T) was preferentially observed in human carcinoma HT29 and A549 cells. Conversely, human embryonal teratocarcinoma NTERA cells were characterized by the presence of multiple c-myc RNA signals located in both the nucleoli and nucleoplasm. When accumulated at nucleoli, c-myc (T) occupied the periphery of this organelle, though not those associated with the cultivation surface. In HT29 cells, approximately 80% of c-myc (T) co-localized with the RNAP II positive regions, so-called transcription factories. However, in approximately 20% of the cells with c-myc transcripts, the c-myc (T) was released from the site of synthesis, and was not associated with either transcription factories or SC35 domains. In approximately 60% of nuclei with c-myc (T), these signals were located in close proximity to the SC35 regions, but promyelocytic leukaemia bodies were associated with c-myc (T) only in approximately 20% of the nuclei. Taken together, c-myc RNA signals were positioned in the most internal parts of the cell nuclei preferentially associated with the nucleoli. Specific nuclear and nucleolar positioning probably reflects the kinetics of c-myc RNA metabolism.

• MeSH
• Cell Nucleus genetics   metabolism   ultrastructure   MeSH
• HT29 Cells MeSH
• Gene Expression MeSH
• Transcription, Genetic MeSH
• Genes, myc * MeSH
• Humans MeSH
• Chromosomes, Human, Pair 8 MeSH
• RNA, Messenger metabolism   MeSH
• Tumor Cells, Cultured MeSH
• Proto-Oncogene Proteins c-myc metabolism   MeSH
• RNA Polymerase II metabolism   MeSH
• Tissue Distribution MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• RNA, Messenger MeSH
• MYC protein, human MeSH Browser
• Proto-Oncogene Proteins c-myc MeSH
• RNA Polymerase II MeSH

It is widely accepted that chromosomes occupy more or less fixed positions in mammalian interphase nucleus. However, relation between large-scale order of chromosome positioning and gene activity remains unclear. We used the model of the human ribosomal genes to address specific aspects of this problem. Ribosomal genes are organized at particular chromosomal sites in clusters termed nucleolus organizer regions (NORs). Only some NORs, called competent are generally accepted to be transcriptionally active during interphase. Importantly in this respect, the regularities in distribution of competent, and non-competent NORs among the specific chromosomes were already established in two human-derived cell lines: transformed HeLa and primary LEP cells. In the present study, using FISH and immunocytochemistry, we found that in HeLa and LEP cells the large-scale positioning of the NOR-bearing chromosomes with regard to nucleoli is linked to the transcription activity of rDNA. Namely, the tendency of rDNA-bearing chromosomes to associate with nucleoli correlates with the number of transcriptionally competent NORs in the respective chromosome homologs. Regarding the position of NORs, we found that not only competent but also most of the non-competent NORs are included in the nucleoli. Some intranucleolar NORs (supposedly non-competent) are situated on elongated chromatin protrusions connecting nucleoli with respective chromosome territories spatially distanced from nucleoli.

• MeSH
• DNA Probes MeSH
• HeLa Cells MeSH
• Interphase MeSH
• Humans MeSH
• Chromosomes, Human * MeSH
• Nucleolus Organizer Region * MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• DNA Probes MeSH