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Mattera V, Occhiuzzi F, Correale J, Pasquini JM. Remyelinating effect driven by transferrin-loaded extracellular vesicles. Glia 2024; 72:338-361. [PMID: 37860913 DOI: 10.1002/glia.24478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 09/21/2023] [Accepted: 09/29/2023] [Indexed: 10/21/2023]
Abstract
Extracellular vesicles (EVs) are involved in diverse cellular functions, playing a significant role in cell-to-cell communication in both physiological conditions and pathological scenarios. Therefore, EVs represent a promising therapeutic strategy. Oligodendrocytes (OLs) are myelinating glial cells developed from oligodendrocyte progenitor cells (OPCs) and damaged in chronic demyelinating diseases such as multiple sclerosis (MS). Glycoprotein transferrin (Tf) plays a critical role in iron homeostasis and has pro-differentiating effects on OLs in vivo and in vitro. In the current work, we evaluated the use of EVs as transporters of Tf to the central nervous system (CNS) through the intranasal (IN) route. For the in vitro mechanistic studies, we used rat plasma EVs. Our results show that EVTf enter OPCs through clathrin-caveolae and cholesterol-rich lipid raft endocytic pathways, releasing the cargo and exerting a pro-maturation effect on OPCs. These effects were also observed in vivo using the animal model of demyelination induced by cuprizone (CPZ). In this model, IN administered Tf-loaded EVs isolated from mouse plasma reached the brain parenchyma, internalizing into OPCs, promoting their differentiation, and accelerating remyelination. Furthermore, in vivo experiments demonstrated that EVs protected the Tf cargo and significantly reduced the amount of Tf required to induce remyelination as compared to soluble Tf. Collectively, these findings unveil EVs as functional nanocarriers of Tf to induce remyelination.
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Affiliation(s)
- Vanesa Mattera
- Departamento de Química Biológica, Instituto de Química y Fisicoquímica Biológica (IQUIFIB), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
| | - Federico Occhiuzzi
- Departamento de Química Biológica, Instituto de Química y Fisicoquímica Biológica (IQUIFIB), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
| | - Jorge Correale
- Departamento de Química Biológica, Instituto de Química y Fisicoquímica Biológica (IQUIFIB), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
- Departamento de Neurología, Fleni, Buenos Aires, Argentina
| | - Juana M Pasquini
- Departamento de Química Biológica, Instituto de Química y Fisicoquímica Biológica (IQUIFIB), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
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2
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Jana M, Ghosh S, Pahan K. Upregulation of Myelin Gene Expression by a Physically-Modified Saline via Phosphatidylinositol 3-Kinase-Mediated Activation of CREB: Implications for Multiple Sclerosis. Neurochem Res 2017; 43:407-419. [PMID: 29143164 PMCID: PMC5799355 DOI: 10.1007/s11064-017-2435-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 10/03/2017] [Accepted: 11/09/2017] [Indexed: 12/29/2022]
Abstract
An increase in central nervous system (CNS) remyelination and a decrease in CNS inflammation are important steps to halt the progression of multiple sclerosis (MS). RNS60 is a bioactive aqueous solution generated by subjecting normal saline to Taylor–Couette–Poiseuille flow under elevated oxygen pressure. Recently we have demonstrated that RNS60 exhibits anti-inflammatory properties. Here, we describe promyelinating property of RNS60. RNS60, but not normal saline (NS), RNS10.3 (TCP-modified saline without excess oxygen) or PNS60 (saline containing excess oxygen without TCP modification), stimulated the expression of myelin-specific genes and proteins (myelin basic protein, MBP; myelin oligodendrocyte glycoprotein, MOG and proteolipid protein, PLP) in primary mouse oligodendroglia and mixed glial cells. While investigating the mechanisms, we found that RNS60 treatment induced the activation of cAMP response element binding protein (CREB) in oligodendrocytes, ultimately leading to the recruitment of CREB to the promoters of myelin-specific genes. Furthermore, activation of type 1A p110β/α, but not type 1B p110γ, phosphatidylinositol-3 (PI-3) kinase by RNS60 together with abrogation of RNS60-mediated activation of CREB and upregulation of myelin genes by LY294002 (a specific inhibitor of PI-3 kinase) suggest that RNS60 upregulates the activation of CREB and the expression of myelin-specific molecules in oligodendrocytes via activation of PI3 kinase. These results highlight a novel promyelinating property of RNS60, which may be of benefit for MS and other demyelinating disorders.
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Affiliation(s)
- Malabendu Jana
- Department of Neurological Sciences, Rush University Medical Center, 1735 West Harrison St, Suite 310, Chicago, IL, 60612, USA
| | - Supurna Ghosh
- Revalesio Corporation, 1200 East D Street, Tacoma, WA, 98421, USA
| | - Kalipada Pahan
- Department of Neurological Sciences, Rush University Medical Center, 1735 West Harrison St, Suite 310, Chicago, IL, 60612, USA.
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3
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Marziali LN, Garcia CI, Pasquini JM. Transferrin and thyroid hormone converge in the control of myelinogenesis. Exp Neurol 2015; 265:129-41. [PMID: 25595122 DOI: 10.1016/j.expneurol.2014.12.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Revised: 12/18/2014] [Accepted: 12/25/2014] [Indexed: 01/20/2023]
Abstract
Myelination is a concerted mechanism tightly regulated in the brain. Although several factors are known to participate during this process, the complete sequence of events is far from being fully elucidated. Separate effects of apotransferrin (aTf) and thyroid hormone (TH) are well documented on rat myelin formation. TH promotes the maturation of oligodendrocyte progenitors (OPCs) into myelinating oligodendrocytes (OLGs), while aTf is able to induce the commitment of neural stem cells (NSCs) toward the oligodendroglial linage and favors OLG maturation. We have also demonstrated that Tf mRNA exhibited a seven-fold increase in hyperthyroid animals. These observations have led us to hypothesize that both factors may interplay during oligodendrogenesis. To assess the combined effects of aTf and TH on proper myelination in the rat brain, Tf expression and oligodendroglial maturation were evaluated at postnatal days 10 (P10) and 20 (P20) in several experimental groups. At P10, an up-regulation of both Tf mRNA and protein, as well as myelination, was found in hyperthyroid animals, while a decrease in Tf mRNA levels and myelin formation was detected in the hypothyroid group. At P20, no differences were found either in Tf mRNA or protein levels between hyperthyroid and control (Ctrol) rats, although differences in OLG differentiation remained. Also at P20, hypothyroid animals showed decreased Tf mRNA and protein levels accompanied with a less mature myelinating phenotype. Moreover, TH and aTf differentially regulate the expression of KLF9 transcription factor as well as TRα and TRβ at P10 and P20. Our results suggest that TH is necessary early in OLG development for aTf action, as exogenous aTf administration was unable to counteract the effect of low TH levels in the hypothyroid state in all the time points analyzed. Furthermore, the fact that hyperthyroidism induced an increase in Tf expression and aTf-dependent regulation of TRα strongly suggests that Tf could be involved in some of TH later effects on OLG maturation. Here we describe the possible relationship between TH and aTf and its implication in oligodendrogenesis.
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Affiliation(s)
- L N Marziali
- Department of Biological Chemistry, Biological and Physical Chemistry Institute (IQUIFIB-CONICET), School of Pharmacy and Biochemistry, University of Buenos Aires, Argentina
| | - C I Garcia
- Department of Pharmacology, School of Pharmacy and Biochemistry, University of Buenos Aires, Argentina
| | - J M Pasquini
- Department of Biological Chemistry, Biological and Physical Chemistry Institute (IQUIFIB-CONICET), School of Pharmacy and Biochemistry, University of Buenos Aires, Argentina.
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4
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Pérez MJ, Fernandez N, Pasquini JM. Oligodendrocyte differentiation and signaling after transferrin internalization: A mechanism of action. Exp Neurol 2013; 248:262-74. [DOI: 10.1016/j.expneurol.2013.06.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 06/12/2013] [Accepted: 06/14/2013] [Indexed: 01/06/2023]
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5
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Malone M, Gary D, Yang IH, Miglioretti A, Houdayer T, Thakor N, McDonald J. Neuronal activity promotes myelination via a cAMP pathway. Glia 2013; 61:843-54. [PMID: 23554117 DOI: 10.1002/glia.22476] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 01/11/2013] [Indexed: 12/17/2022]
Abstract
Neuronal activity promotes myelination in vivo and in vitro. However, the molecular events that mediate activity-dependent myelination are not completely understood. Seven, daily 1 h sessions of patterned electrical stimulation (ESTIM) promoted myelin segment formation in mixed cultures of dorsal root ganglion (DRG) neurons and oligodendrocytes (OLs); the increase in myelination was frequency-dependent. Myelin segment formation was also enhanced following exposure of DRGs to ESTIM prior to OL addition, suggesting that ESTIM promotes myelination in a manner involving neuron-specific signaling. Cyclic adenosine monophosphate (cAMP) levels in DRGs were increased three-fold following ESTIM, and artificially increasing cAMP mimicked the ability of ESTIM to promote myelination. Alternatively, inhibiting the cAMP pathway suppressed ESTIM-induced myelination. We used compartmentalized, microfluidic platforms to isolate DRG soma from OLs and assessed cell-type specific effects of ESTIM on myelination. A selective increase or decrease in DRG cAMP levels resulted in enhanced or suppressed myelination, respectively. This work describes a novel role for the cAMP pathway in neurons that results in enhanced myelination.
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Affiliation(s)
- Misti Malone
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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6
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Salis C, Davio C, Usach V, Urtasun N, Goitia B, Martinez-Vivot R, Pasquini JM, Setton-Avruj CP. Iron and holotransferrin induce cAMP-dependent differentiation of Schwann cells. Neurochem Int 2012; 61:798-806. [PMID: 22776360 DOI: 10.1016/j.neuint.2012.06.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 06/21/2012] [Accepted: 06/26/2012] [Indexed: 10/28/2022]
Abstract
The differentiation of myelin-forming Schwann cells (SC) is completed with the appearance of myelin proteins MBP and P(0) and a concomitant downregulation of markers GFAP and p75NTR, which are expressed by immature and adult non-myelin-forming SC. We have previously demonstrated that holotransferrin (hTf) can prevent SC dedifferentiation in culture (Salis et al., 2002), while apotransferrin (aTf) cannot. As a consequence, we used pure cultured SC and submitted them to serum deprivation in order to promote dedifferentiation and evaluate the prodifferentiating ability of ferric ammonium citrate (FAC) through the expression of MBP, P(0), p75NTR and c-myc. The levels of cAMP, CREB and p-CREB were also measured. Results show that Fe(3+), either in its free form or as hTf, can prevent the dedifferentiation promoted by serum withdrawal. Both FAC and hTf were proven to promote differentiation, probably through the increase in cAMP levels and CREB phosphorylation, as well as levels of reactive oxygen species. This effect was inhibited by deferroxamine (Dfx, an iron chelator), H9 (a cAMP-PKA antagonist) and N-acetylcysteine (NAC, a powerful antioxidant).
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Affiliation(s)
- C Salis
- Instituto de Química y Fisicoquímica Biológica (IQUIFIB), UBA-CONICET, Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires C1113AAD, Argentina
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7
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Njaine B, Martins RAP, Santiago MF, Linden R, Silveira MS. Pituitary adenylyl cyclase-activating polypeptide controls the proliferation of retinal progenitor cells through downregulation of cyclin D1. Eur J Neurosci 2010; 32:311-21. [PMID: 20646049 DOI: 10.1111/j.1460-9568.2010.07286.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
During retinal development, cell proliferation and exit from the cell cycle must be precisely regulated to ensure the generation of the appropriate numbers and proportions of the various retinal cell types. Previously, we showed that pituitary adenylyl cyclase-activating polypeptide (PACAP) exerts a neuroprotective effect in the developing retina of rats, through the cAMP-cAMP-dependent protein kinase (protein kinase A) (PKA) pathway. Here, we show that PACAP also regulates the proliferation of retinal progenitor cells. PACAP, PACAP-specific receptor (PAC1), and the receptors activated by both PACAP and vasoactive intestinal peptide (VIP), VPAC1 and VPAC2, are expressed during embryonic and postnatal development of the rat retina. Treatment of retinal explants with PACAP38 reduced the incorporation of [(3)H]thymidine as well as the number of 5-bromo-2'-deoxyuridine-positive and cyclin D1-positive cells. Pharmacological experiments indicated that PACAP triggers this antiproliferative effect through the activation of both PAC1 and VPACs, and the cAMP-PKA pathway. In addition, PACAP receptor activation decreased both cyclin D1 mRNA and protein content. Altogether, the data support the hypothesis that PACAP is a cell-extrinsic regulator with multiple roles during retinal development, including the regulation of proliferation in a subpopulation of retinal progenitor cells.
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Affiliation(s)
- Brian Njaine
- Instituto de Biofisica Carlos Chagas Filho-UFRJ, Edifício do Centro de Ciencias da Saude, Ilha do Fundão, Rio de Janeiro, Brazil
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8
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Lin G, Mela A, Guilfoyle EM, Goldman JE. Neonatal and adult O4(+) oligodendrocyte lineage cells display different growth factor responses and different gene expression patterns. J Neurosci Res 2010; 87:3390-402. [PMID: 19360905 DOI: 10.1002/jnr.22065] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Oligodendrocytes are the myelinating cells of the central nervous system. Although the CNS possesses the ability to repair demyelinating insults, in certain cases, such as the chronic lesions found in multiple sclerosis, remyelination fails. Cycling cells capable of becoming oligodendrocytes have been identified in both the developing and the adult mammalian forebrain. Many studies have focused on differences in gene expression profiles as oligodendrocyte progenitors differentiate into myelinating oligodendrocytes by isolating cells at different developmental stages from animals at a single age. However, few have studied the differences that exist between the progenitors of the neonatal CNS and those of the adult CNS. This study examined the response of neonatal and adult O4(+) cells to platelet-derived growth factor-AA, basic fibroblast growth factor, and insulin-like growth factor-1 and revealed marked differences. Whereas adult cells readily differentiated in vitro, the majority of neonatal progenitors remained immature. Microarray analysis was used to examine differences between acutely isolated neonatal and adult progenitors further. Gene expression profiles showed that the adult O4(+) cells are more developmentally mature than neonatal cells. Neonatal cells expressed higher levels of genes involved in proliferation. Adult O4(+) cells expressed higher levels of transcripts for genes involved in cell death and survival. Therefore, O4(+) cells from the adult differ greatly from those of the neonate, and the developmental stage of the animal models utilized must be taken into consideration when applying principles from neonatal systems to the adult.
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Affiliation(s)
- Grace Lin
- Department of Pathology and Cell Biology, Columbia University, New York, New York, USA
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9
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Thomson CE, McCulloch M, Sorenson A, Barnett SC, Seed BV, Griffiths IR, McLaughlin M. Myelinated, synapsing cultures of murine spinal cord--validation as an in vitro model of the central nervous system. Eur J Neurosci 2008; 28:1518-35. [PMID: 18793322 PMCID: PMC2777255 DOI: 10.1111/j.1460-9568.2008.06415.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Research in central nervous system (CNS) biology and pathology requires in vitro models, which, to recapitulate the CNS in vivo, must have extensive myelin and synapse formation under serum-free (defined) conditions. However, finding such a model has proven difficult. The technique described here produces dense cultures of myelinated axons, with abundant synapses and nodes of Ranvier, that are suitable for both morphological and biochemical analysis. Cellular and molecular events were easily visualised using conventional microscopy. Ultrastructurally, myelin sheaths were of the appropriate thickness relative to axonal diameter (G-ratio). Production of myelinated axons in these cultures was consistent and repeatable, as shown by statistical analysis of multiple experimental repeats. Myelinated axons were so abundant that from one litter of embryonic mice, myelin was produced in amounts sufficient for bulk biochemical analysis. This culture method was assessed for its ability to generate an in vitro model of the CNS that could be used for both neurobiological and neuropathological research. Myelin protein kinetics were investigated using a myelin fraction isolated from the cultures. This fraction was found to be superior, quantitatively and qualitatively, to the fraction recovered from standard cultures of dissociated oligodendrocytes, or from brain slices. The model was also used to investigate the roles of specific molecules in the pathogenesis of inflammatory CNS diseases. Using the defined conditions offered by this culture system, dose-specific, inhibitory effects of inflammatory cytokines on myelin formation were demonstrated, unequivocally. The method is technically quick, easy and reliable, and should have wide application to CNS research.
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Affiliation(s)
- C E Thomson
- Comparative Anatomy and Physiology, Institute of Veterinary, Biomedical and Animal Sciences, Massey University, Palmerston North, New Zealand.
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10
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Chang YC, Huang CC, Hung PL, Huang HM. Rolipram, a phosphodiesterase type IV inhibitor, exacerbates periventricular white matter lesions in rat pups. Pediatr Res 2008; 64:234-9. [PMID: 18437099 DOI: 10.1203/pdr.0b013e31817cfc87] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Periventricular white matter injury is the leading cause of cerebral palsy in premature infants for which no effective treatments are available. Our previous studies have demonstrated that pharmacological activation of the cAMP response element-binding protein (CREB) signaling pathway, before hypoxic-ischemia protected against neuronal injury in neonatal rats. We examined whether rolipram, a phosphodiesterase type IV inhibitor, treatment after hypoxic-ischemia is protective against white matter injury in neonatal rats. Rats were exposed to hypoxia-ischemia (HI) on P7 and then treated with daily injections of various doses of rolipram (P7-P11). Immunohistochemical staining for myelin basic protein, ED1, glial fibrillary acidic protein, CREB and O1 were examined on P11. We found that the periventricular white matter and deep cortical lesions were exacerbated by rolipram administration after HI injury. The lesions in the rolipram-treated group also showed increased astrogliosis and increased CREB phosphorylation in the activated microglia and astrocytes. Furthermore, the rolipram-posttreated HI group had markedly depleted preoligodendrocytes in the ipsilateral hemisphere, which may be related to decreased preoligodendrocytes proliferation after rolipram treatment per se. These data suggest that rolipram treatment after hypoxic-ischemia is not protective; in contrast, rolipram may exacerbate hypoxic-ischemic white matter injury in neonatal rat brains.
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Affiliation(s)
- Ying-Chao Chang
- Department of Pediatrics, Chang Gung Memorial Hospital, Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
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11
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Salvati S, Natali F, Attorri L, Di Benedetto R, Leonardi F, Di Biase A, Ferri F, Fortuna S, Lorenzini P, Sanchez M, Ricceri L, Vitelli L. Eicosapentaenoic acid stimulates the expression of myelin proteins in rat brain. J Neurosci Res 2008; 86:776-84. [PMID: 17941053 DOI: 10.1002/jnr.21537] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We have previously demonstrated that, in C6 glioma cells, eicosapentaenoic acid (EPA) stimulates the expression of proteolipid protein (PLP) via cAMP-mediated pathways. In this study, we investigated whether n-3 polyunsaturated fatty acids can affect myelinogenesis in vivo. A single dose of either EPA or docosahexaenoic acid (DHA) was injected intracerebroventricularly into 2-day-old rats, which were then killed after 3 days post-injection (p.i.). Total RNA was isolated from the medulla, cerebellum, and cortex, and the expression of myelin-specific mRNAs was analyzed by real-time PCR. The levels of PLP, myelin basic protein, and myelin oligodendrocyte protein mRNAs increased in nearly all brain regions of DHA- and EPA-treated animals, but the effect was more pronounced in EPA-treated rats. The enhancement in PLP transcript levels was followed by an increase in PLP translation in EPA-treated rats. A further indicator of accelerated myelination was the increase in 2'-3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) protein levels. In EPA-treated rats, the increased expression of myelin genes coincided with a decrease of cAMP-response element-binding protein (CREB)-DNA binding in the cerebellum and cortex (1 hr p.i.). After 16 hr, this effect was still present in the same cerebral regions even though the decrease in EPA-treated rats was less pronounced than in controls. The down-regulation of CREB activity was due to a decrease in the levels of CREB phosphorylation. In conclusion, our data suggest that EPA stimulates the expression of specific myelin proteins through decreased CREB phosphorylation. These results corroborate the clinical studies of the n-3 PUFA beneficial effects on several demyelinating diseases.
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Affiliation(s)
- Serafina Salvati
- Department of Food, Nutrition and Health, Istituto Superiore di Sanità, Rome, Italy.
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12
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Bhat NR, Zhang P, Mohanty SB. p38 MAP kinase regulation of oligodendrocyte differentiation with CREB as a potential target. Neurochem Res 2007; 32:293-302. [PMID: 17235686 DOI: 10.1007/s11064-006-9274-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Accepted: 09/06/2006] [Indexed: 10/23/2022]
Abstract
Despite a substantial understanding of the factors regulating oligodendrocyte differentiation, the signaling mechanisms involved in this process are not well-understood. This study elaborates on the findings (Bhat NR, Zhang P (1997) FASEB J 11:A925; Baron W, Metz B, Bansal R, Hoekstra D, de Vries H (2000) Mol Cell Neurosci 15:314-329) of a role for p38 MAP kinase signaling in oligodendrocyte differentiation and myelin gene expression. When proliferating oligodendrocyte progenitors were switched to a growth factor-free differentiation medium, there was a rapid activation of p38 kinase that correlated with an increased phosphorylation of CREB, a down-stream target and a factor involved in oligodendrocyte differentiation. Addition of forskolin, a known inducer of intracellular c-AMP and of oligodendrocyte differentiation, also stimulated CREB phosphorylation in a p38 kinase dependent way. Pharmacological inhibition of p38 interfered with the morphological and antigenic changes associated with differentiating oligodendrocytes as well as with the developmental and forskolin-induced expression of myelin basic protein, thereby supporting an essential role for p38 MAPK pathway in oligodendrocyte differentiation.
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Affiliation(s)
- Narayan R Bhat
- Department of Neurosciences, Medical University of South Carolina, 171 Ashley Avenue, Charleston, SC 29425, USA.
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13
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Paez PM, García CI, Pasquini JM. Expression of myelin basic protein in two oligodendroglial cell lines is modulated by apotransferrin through different transcription factors. J Neurosci Res 2006; 83:606-18. [PMID: 16435391 DOI: 10.1002/jnr.20750] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We have shown that apotransferrin (aTf) promotes the differentiation of two oligodendroglial cell (OLGc) lines, N19 and N20.1, representing different stages of OLGc maturation. Although in both cell lines aTf promoted myelin basic protein (MBP) expression, an increase in cAMP levels and CREB phosphorylation was observed only in the less mature cells (N19), suggesting that the maturation induced by aTf is achieved probably through different signaling pathways. We transfected both cell lines with the proximal region of the human MBP promoter fused to the lacZ reporter gene. In both transfected cell lines, addition of aTf produced an activation of the promoter. To elucidate the mechanisms involved in this action, Western blot analysis, EMSAs, and RT-PCR were performed for different transcription factors involved in mbp regulation. In the N20.1 line, treatment with aTf increased the expression and the DNA-binding capacity of thyroid hormone (TH) receptors, Sp1, and nuclear factor-kappaB (NFkappaB). For these cells we found that an inductor of NFkappaB (tumor necrosis factor-alpha) promoted MBP messenger synthesis, whereas mithramycin, a specific inibitor of Sp1, and a cAMP analog (db-cAMP) inhibited its transcription. In the N19 cell line, aTf stimulated NF-I and NFkappaB activation, but, aside from aTf, only db-cAMP induced mbp transcription. These data suggest that, depending on the OLGc maturational stage, aTf modulates MBP expression and OLGc differentiation through different signaling pathways and different transcription factors.
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Affiliation(s)
- Pablo M Paez
- Instituto de Química y Fisicoquímica Biológica (IQUIFIB), UBA-CONICET, Buenos Aires, Argentina
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14
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Kang J, Shi Y, Xiang B, Qu B, Su W, Zhu M, Zhang M, Bao G, Wang F, Zhang X, Yang R, Fan F, Chen X, Pei G, Ma L. A nuclear function of beta-arrestin1 in GPCR signaling: regulation of histone acetylation and gene transcription. Cell 2006; 123:833-47. [PMID: 16325578 DOI: 10.1016/j.cell.2005.09.011] [Citation(s) in RCA: 252] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2005] [Revised: 07/07/2005] [Accepted: 09/12/2005] [Indexed: 01/07/2023]
Abstract
Chromatin modification is considered to be a fundamental mechanism of regulating gene expression to generate coordinated responses to environmental changes, however, whether it could be directly regulated by signals mediated by G protein-coupled receptors (GPCRs), the largest surface receptor family, is not known. Here, we show that stimulation of delta-opioid receptor, a member of the GPCR family, induces nuclear translocation of beta-arrestin 1 (betaarr1), which was previously known as a cytosolic regulator and scaffold of GPCR signaling. In response to receptor activation, betaarr1 translocates to the nucleus and is selectively enriched at specific promoters such as that of p27 and c-fos, where it facilitates the recruitment of histone acetyltransferase p300, resulting in enhanced local histone H4 acetylation and transcription of these genes. Our results reveal a novel function of betaarr1 as a cytoplasm-nucleus messenger in GPCR signaling and elucidate an epigenetic mechanism for direct GPCR signaling from cell membrane to the nucleus through signal-dependent histone modification.
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MESH Headings
- Acetylation
- Active Transport, Cell Nucleus/physiology
- Animals
- Arrestins/genetics
- Arrestins/metabolism
- Cell Line
- Cell Nucleus/metabolism
- Chromatin/metabolism
- Cyclin-Dependent Kinase Inhibitor p27/genetics
- Cyclin-Dependent Kinase Inhibitor p27/metabolism
- Epigenesis, Genetic
- Gene Expression Regulation
- Histones/metabolism
- Humans
- Mice
- Mice, Knockout
- Promoter Regions, Genetic
- Proto-Oncogene Proteins c-fos/genetics
- Proto-Oncogene Proteins c-fos/metabolism
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Opioid, delta/genetics
- Receptors, Opioid, delta/metabolism
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Signal Transduction/physiology
- Transcription, Genetic
- beta-Arrestin 1
- beta-Arrestins
- p300-CBP Transcription Factors/metabolism
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Affiliation(s)
- Jiuhong Kang
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Graduate School, Chinese Academy of Sciences, Shanghai 200031, China
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Woodmansee WW, Kerr JM, Tucker EA, Mitchell JR, Haakinson DJ, Gordon DF, Ridgway EC, Wood WM. The proliferative status of thyrotropes is dependent on modulation of specific cell cycle regulators by thyroid hormone. Endocrinology 2006; 147:272-82. [PMID: 16223861 DOI: 10.1210/en.2005-1013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In this report we have examined changes in cell growth parameters, cell cycle effectors, and signaling pathways that accompany thyrotrope growth arrest by thyroid hormone (TH) and growth resumption after its withdrawal. Flow cytometry and immunohistochemistry of proliferation markers demonstrated that TH treatment of thyrotrope tumors resulted in a reduction in the fraction of cells in S-phase that is restored upon TH withdrawal. This is accompanied by dephosphorylation and rephosphorylation of retinoblastoma (Rb) protein. The expression levels of cyclin-dependent kinase 2 and cyclin A, as well as cyclin-dependent kinase 1 and cyclin B, were decreased by TH, and after withdrawal not only did these regulators of Rb phosphorylation and mitosis increase in their expression but so too did the D1 and D3 cyclins. We also noted a rapid induction and subsequent disappearance of the type 5 receptor for the growth inhibitor somatostatin with TH treatment and withdrawal, respectively. Because somatostatin can arrest growth by activating MAPK pathways, we examined these pathways in TtT-97 tumors and found that the ERK pathway and several of its upstream and downstream effectors, including cAMP response element binding protein, were activated with TH treatment and deactivated after its withdrawal. This led to the hypothesis that TH, acting through increased type 5 somatostatin receptor, could activate the ERK pathway leading to cAMP response element binding protein-dependent decreased expression of critical cell cycle proteins, specifically cyclin A, resulting in hypophosphorylation of Rb and its subsequent arrest of S-phase progression. These processes are reversed when TH is withdrawn, resulting in an increase in the fraction of S-phase cells.
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Affiliation(s)
- Whitney W Woodmansee
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado 80045, USA
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