The Experts below are selected from a list of 123 Experts worldwide ranked by ideXlab platform
Anders A. F. Sima - One of the best experts on this subject based on the ideXlab platform.
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Expression and localization of insulin receptor in rat dorsal root ganglion and spinal cord.
Journal of the peripheral nervous system : JPNS, 2002Co-Authors: Kazuhiro Sugimoto, Yuichi Murakawa, Anders A. F. SimaAbstract:The expression and localization of the insulin receptor (IR) was examined in rat dorsal root ganglia (DRG) and spinal cord using Western blotting, in situ hybridization and immunocytochemistry. Western blotting showed that the molecular weight of the IR beta subunit was higher in PNS than that found in CNS. Both IR mRNA and protein expressions were highest in small-sized sensory DRG neurons and myelinated sensory root fibers expressed higher levels of IR protein than myelinated anterior root fibers. In the spinal cord, IR immunoreactive neurons were present in lateral lamina V and in lamina X, suggesting the presence of IR in nociceptive pathways. Electronmicroscopy of DRGs revealed a polarized localization of the IR in abaxonal Schwann cell membranes, outer Mesaxons in close vicinity to tight junctions of both myelinating and non-myelinating Schwann cells and to plasma membranes of sensory neurons. From these findings, we speculate that insulin may play a role in sensory fibers involved in nociceptive function often perturbed in diabetic neuropathy. The high expression of IR localizing to tight junctions of dorsal root Mesaxons of DRGs may suggest a regulatory role on barrier functions compensating for the lack of a blood-nerve barrier in dorsal root ganglia. This is consistent with the colocalization of IR with tight junctions of the paranodal barrier and endoneurial endothelial cells in peripheral nerve.
Takashi Kojima - One of the best experts on this subject based on the ideXlab platform.
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tricellulin is expressed in autotypic tight junctions of peripheral myelinating schwann cells
Journal of Histochemistry and Cytochemistry, 2010Co-Authors: Shin Kikuchi, Takafumi Ninomiya, Haruyuki Tatsumi, Norimasa Sawada, Takashi KojimaAbstract:The myelin membrane is divided into two structurally and biochemically distinct regions, compact myelin and non-compact myelin (Poliak et al. 2002; Ryu et al. 2008). Compact myelin forms many layers composed of the major dense line and the intraperiod line. Non-compact myelin regions are found in the paranodal loops, Schmidt–Lanterman incisures, and the inner and outer Mesaxons. Areas of non-compact myelin contain several types of specialized junctions, including tight, gap, and adherens junctions, which are found in epithelial cells (Mugnaini and Schnapp 1974; Fannon et al. 1995; Balice-Gordon et al. 1998; Poliak et al. 2002; Spiegel and Peles 2002). These junctions are found between membrane lamellae of the same cell and are termed autotypic tight, gap, and adherens junctions, respectively (Trapp et al. 1989; Fannon et al. 1995; Scherer et al. 1995; Gumbiner 2000; Altevogt et al. 2002). Autotypic tight junctions are observed as tight junction strands between adjacent cell membranes in the inner and outer Mesaxon, paranodal loops, and Schmidt–Lanterman incisures in the peripheral myelin sheath by freeze-fracture electron microscopy (Sandri et al. 1977; Tetzlaff 1978,1982). They are proposed to function as a mechanical link and as a permeability barrier separating the extracellular space outside the myelin sheath from the intramyelinic space between the lamellae (Hall and Williams 1969; Revel and Hamilton 1969; Mugnaini and Schnapp 1974; Tabira et al. 1978; MacKenzie et al. 1984). The autotypic tight junctions present in different components of non-compact myelin contain distinct junctional complexes including the paranodal loops, Schmidt–Lanterman incisures, and Mesaxons (Poliak et al. 2002). Tight junctions in endothelial and epithelial cells consist of not only the integral membrane proteins claudins (Cldns), occludin, and junctional adhesion molecule (JAMs) but also many peripheral membrane proteins, including the scaffold PDZ-domain expression proteins zonula occludens (ZO)-1, ZO-2, ZO-3, multi-PDZ domain protein-1 (MUPP1) and membrane-associated guanylate kinase with inverted orientation (MAGI)-1, MAGI-2, MAGI-3, and cell polarity molecules ASIP/PAR-3, PAR-6, PALS-1, and PALS-1-associated tight junction (PATJ) and the non–PDZ-expressing proteins, cingulin, symplekin, ZONAB, GEF-H1, aPKC, PP2A, Rab3b, Rab13, PTEN, and 7H6 (Tsukita et al. 2001; Sawada et al. 2003; Schneeberger and Lynch 2004). More recently, tricellulin (TRIC) was identified as the first marker of the tricellular tight junction in epithelial cells. The loss of TRIC affects the organization of the tricellular tight junction and the barrier function of epithelial cells (Ikenouchi et al. 2005). Autotypic tight junctions of myelinating Schwann cells are also composed of various transmembrane and peripheral cytoplasmic tight junction proteins, including Cldn-19 and JAM-C (Miyamoto et al. 2005; Scheiermann et al. 2007). However, in the autotypic tight junctions of myelinating Schwann cells, little is known about the expression and localization of TRIC, which may play a crucial role in bicellular and tricellular tight junctions of epithelial cells. In this study, our findings demonstrate the identification and subcellular distribution of the novel tricellular tight junction protein TRIC in autotypic tight junctions of mouse myelinating Schwann cells, compared with the autotypic adherens junction protein E-cadherin and the autotypic tight junction protein JAM-C, which are expressed in the paranodal loops, Schmidt–Lanterman incisures, and Mesaxons.
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Tricellulin is expressed in autotypic tight junctions of peripheral myelinating Schwann cells.
The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society, 2010Co-Authors: Shin Kikuchi, Takafumi Ninomiya, Haruyuki Tatsumi, Norimasa Sawada, Takashi KojimaAbstract:Autotypic tight junctions are formed by tight junction-like structures in three regions of myelinating Schwann cells, the paranodal loops, Schmidt-Lanterman incisures, and outer/inner Mesaxons, and various tight junction molecules, including claudin-19 and junctional adhesion molecule (JAM)-C. Our findings demonstrate the identification and subcellular distribution of a novel tricellular tight junction protein, tricellulin (TRIC), in the autotypic tight junctions of mouse myelinating Schwann cells, compared with the autotypic adherens junction protein E-cadherin and the autotypic tight junction protein JAM-C, which are expressed in the paranodal loops, Schmidt-Lanterman incisures, and Mesaxons. In real-time RT-PCR, the expression level of TRIC mRNA was about 10-fold higher in the sciatic nerve than in the spinal cord or cerebrum. In immunostaining, TRIC signals were completely restricted to the peripheral nervous system (PNS) and strongly concentrated at the paranodal loops, Schmidt-Lanterman incisures, and Mesaxons of myelinating Schwann cells. In addition, TRIC was expressed in the thin region of the paranode and there was a gap between TRIC and the Na+ channel. Furthermore, TRIC was more distally located from the node than E-cadherin and was colocalized with JAM-C. It is possible that TRIC may be a component to maintain the integrity for PNS myelin function and morphology. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.
Kazuhiro Sugimoto - One of the best experts on this subject based on the ideXlab platform.
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Expression and localization of insulin receptor in rat dorsal root ganglion and spinal cord.
Journal of the peripheral nervous system : JPNS, 2002Co-Authors: Kazuhiro Sugimoto, Yuichi Murakawa, Anders A. F. SimaAbstract:The expression and localization of the insulin receptor (IR) was examined in rat dorsal root ganglia (DRG) and spinal cord using Western blotting, in situ hybridization and immunocytochemistry. Western blotting showed that the molecular weight of the IR beta subunit was higher in PNS than that found in CNS. Both IR mRNA and protein expressions were highest in small-sized sensory DRG neurons and myelinated sensory root fibers expressed higher levels of IR protein than myelinated anterior root fibers. In the spinal cord, IR immunoreactive neurons were present in lateral lamina V and in lamina X, suggesting the presence of IR in nociceptive pathways. Electronmicroscopy of DRGs revealed a polarized localization of the IR in abaxonal Schwann cell membranes, outer Mesaxons in close vicinity to tight junctions of both myelinating and non-myelinating Schwann cells and to plasma membranes of sensory neurons. From these findings, we speculate that insulin may play a role in sensory fibers involved in nociceptive function often perturbed in diabetic neuropathy. The high expression of IR localizing to tight junctions of dorsal root Mesaxons of DRGs may suggest a regulatory role on barrier functions compensating for the lack of a blood-nerve barrier in dorsal root ganglia. This is consistent with the colocalization of IR with tight junctions of the paranodal barrier and endoneurial endothelial cells in peripheral nerve.
Shin Kikuchi - One of the best experts on this subject based on the ideXlab platform.
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tricellulin is expressed in autotypic tight junctions of peripheral myelinating schwann cells
Journal of Histochemistry and Cytochemistry, 2010Co-Authors: Shin Kikuchi, Takafumi Ninomiya, Haruyuki Tatsumi, Norimasa Sawada, Takashi KojimaAbstract:The myelin membrane is divided into two structurally and biochemically distinct regions, compact myelin and non-compact myelin (Poliak et al. 2002; Ryu et al. 2008). Compact myelin forms many layers composed of the major dense line and the intraperiod line. Non-compact myelin regions are found in the paranodal loops, Schmidt–Lanterman incisures, and the inner and outer Mesaxons. Areas of non-compact myelin contain several types of specialized junctions, including tight, gap, and adherens junctions, which are found in epithelial cells (Mugnaini and Schnapp 1974; Fannon et al. 1995; Balice-Gordon et al. 1998; Poliak et al. 2002; Spiegel and Peles 2002). These junctions are found between membrane lamellae of the same cell and are termed autotypic tight, gap, and adherens junctions, respectively (Trapp et al. 1989; Fannon et al. 1995; Scherer et al. 1995; Gumbiner 2000; Altevogt et al. 2002). Autotypic tight junctions are observed as tight junction strands between adjacent cell membranes in the inner and outer Mesaxon, paranodal loops, and Schmidt–Lanterman incisures in the peripheral myelin sheath by freeze-fracture electron microscopy (Sandri et al. 1977; Tetzlaff 1978,1982). They are proposed to function as a mechanical link and as a permeability barrier separating the extracellular space outside the myelin sheath from the intramyelinic space between the lamellae (Hall and Williams 1969; Revel and Hamilton 1969; Mugnaini and Schnapp 1974; Tabira et al. 1978; MacKenzie et al. 1984). The autotypic tight junctions present in different components of non-compact myelin contain distinct junctional complexes including the paranodal loops, Schmidt–Lanterman incisures, and Mesaxons (Poliak et al. 2002). Tight junctions in endothelial and epithelial cells consist of not only the integral membrane proteins claudins (Cldns), occludin, and junctional adhesion molecule (JAMs) but also many peripheral membrane proteins, including the scaffold PDZ-domain expression proteins zonula occludens (ZO)-1, ZO-2, ZO-3, multi-PDZ domain protein-1 (MUPP1) and membrane-associated guanylate kinase with inverted orientation (MAGI)-1, MAGI-2, MAGI-3, and cell polarity molecules ASIP/PAR-3, PAR-6, PALS-1, and PALS-1-associated tight junction (PATJ) and the non–PDZ-expressing proteins, cingulin, symplekin, ZONAB, GEF-H1, aPKC, PP2A, Rab3b, Rab13, PTEN, and 7H6 (Tsukita et al. 2001; Sawada et al. 2003; Schneeberger and Lynch 2004). More recently, tricellulin (TRIC) was identified as the first marker of the tricellular tight junction in epithelial cells. The loss of TRIC affects the organization of the tricellular tight junction and the barrier function of epithelial cells (Ikenouchi et al. 2005). Autotypic tight junctions of myelinating Schwann cells are also composed of various transmembrane and peripheral cytoplasmic tight junction proteins, including Cldn-19 and JAM-C (Miyamoto et al. 2005; Scheiermann et al. 2007). However, in the autotypic tight junctions of myelinating Schwann cells, little is known about the expression and localization of TRIC, which may play a crucial role in bicellular and tricellular tight junctions of epithelial cells. In this study, our findings demonstrate the identification and subcellular distribution of the novel tricellular tight junction protein TRIC in autotypic tight junctions of mouse myelinating Schwann cells, compared with the autotypic adherens junction protein E-cadherin and the autotypic tight junction protein JAM-C, which are expressed in the paranodal loops, Schmidt–Lanterman incisures, and Mesaxons.
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Tricellulin is expressed in autotypic tight junctions of peripheral myelinating Schwann cells.
The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society, 2010Co-Authors: Shin Kikuchi, Takafumi Ninomiya, Haruyuki Tatsumi, Norimasa Sawada, Takashi KojimaAbstract:Autotypic tight junctions are formed by tight junction-like structures in three regions of myelinating Schwann cells, the paranodal loops, Schmidt-Lanterman incisures, and outer/inner Mesaxons, and various tight junction molecules, including claudin-19 and junctional adhesion molecule (JAM)-C. Our findings demonstrate the identification and subcellular distribution of a novel tricellular tight junction protein, tricellulin (TRIC), in the autotypic tight junctions of mouse myelinating Schwann cells, compared with the autotypic adherens junction protein E-cadherin and the autotypic tight junction protein JAM-C, which are expressed in the paranodal loops, Schmidt-Lanterman incisures, and Mesaxons. In real-time RT-PCR, the expression level of TRIC mRNA was about 10-fold higher in the sciatic nerve than in the spinal cord or cerebrum. In immunostaining, TRIC signals were completely restricted to the peripheral nervous system (PNS) and strongly concentrated at the paranodal loops, Schmidt-Lanterman incisures, and Mesaxons of myelinating Schwann cells. In addition, TRIC was expressed in the thin region of the paranode and there was a gap between TRIC and the Na+ channel. Furthermore, TRIC was more distally located from the node than E-cadherin and was colocalized with JAM-C. It is possible that TRIC may be a component to maintain the integrity for PNS myelin function and morphology. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.
Gillian Mcgovern - One of the best experts on this subject based on the ideXlab platform.
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Altered trafficking of abnormal prion protein in atypical scrapie: prion protein accumulation in oligodendroglial inner Mesaxons
Neuropathology and applied neurobiology, 2016Co-Authors: Martin Jeffrey, Lorenzo González, Marion M Simmons, Nora Hunter, Stuart Martin, Gillian McgovernAbstract:AIMS Prion diseases exist in classical and atypical disease forms. Both forms are characterized by disease-associated accumulation of a host membrane sialoglycoprotein known as prion protein (PrPd ). In classical forms of prion diseases, PrPd can accumulate in the extracellular space as fibrillar amyloid, intracellularly within lysosomes, but mainly on membranes in association with unique and characteristic membrane pathology. These membrane changes are found in all species and strains of classical prion diseases and consist of spiral, branched and clathrin-coated membrane invaginations on dendrites. Atypical prion diseases have been described in ruminants and man and have distinct biological, biochemical and pathological properties when compared to classical disease. The purpose of this study was to determine whether the subcellular pattern of PrPd accumulation and membrane changes in atypical scrapie were the same as those found in classical prion diseases. METHODS Immunogold electron microscopy was used to examine brains of atypical scrapie-affected sheep and Tg338 mice. RESULTS Classical prion disease-associated membrane lesions were not found in atypical scrapie-affected sheep, however, white matter PrPd accumulation was localized mainly to the inner Mesaxon and paranodal cytoplasm of oligodendroglia. Similar lesions were found in myelinated axons of atypical scrapie Tg338-infected mice. However, Tg338 mice also showed the unique grey matter membrane changes seen in classical forms of disease. CONCLUSIONS These data show that atypical scrapie infection directs a change in trafficking of abnormal PrP to axons and oligodendroglia and that the resulting pathology is an interaction between the agent strain and host genotype.