Müller glial cells of the tree shrew retina

Reichenbach, Andreas; Frömter, C.; Engelmann, Ralf; Wolburg, Hartwig; Kasper, Michael; Schnitzer, Jutta

doi:10.1002/cne.903600205

Cited by 31 publications

(22 citation statements)

References 44 publications

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“…2). The dark appearance of the cytoplasm of Mu$ ller cells represents a reliable criterion for their ultrastructural identification that has already been applied, by others, to Tupaia belangeri (Reichenbach et al 1995) as well as many other species (Holla$ nder et al 1991 ;Ramirez et al 1996). We never observed cell processes revealing transitions between electron-dense and electron-lucent cytoplasm.…”

Section: supporting

confidence: 55%

“…In Tupaia, the distribution of retinal macroglial cells (Reichenbach et al 1995 ;Knabe & Ochs, 1999) conforms to the basic mammalian pattern : the occurrence of astrocytes is restricted to the inner parts of the retina, whereas Mu$ ller cells extend throughout the entire depth of the retina (Chan-Ling, 1994). The present stereological study demonstrates that, in Tupaia, the contribution of Mu$ ller cells to the investment of retinal capillaries is distinctly different among the 3 outermost capillary layers studied.…”

Section: mentioning

confidence: 89%

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To what extent are the retinal capillaries ensheathed by Müller cells? A stereological study in the tree shrew Tupaia belangeri

2000

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The cellular ensheathment of capillaries in the 3 outer capillary layers of the central retina of the adult tree shrew Tupaia belangeri was studied quantitatively by transmission electron microscopy. Using a stereological approach, the relative surface of capillary basal lamina ensheathed by Mu$ ller cells and by nonmacroglial cells (collectively termed non-Mu$ ller cells) was estimated in 5 animals. The participation of Mu$ ller cells was distinctly different in the 3 capillary layers studied. In the outermost capillary layer 1, the mean (standard deviation) percentage surface coverage by non-Mu$ ller cell processes was 46n8 (15n3) %. Much less of the capillary basal lamina was ensheathed by non-Mu$ ller cells in capillary layers 2 and 3 (3n0 (2n1) % and 0n3 (0n3) % respectively). The observed total variation of the stereological estimates for the surface fraction of Mu$ ller cells (expressed as the between-subject coefficient of variation) was significantly higher in capillary layer 1 (28n8 %) compared with capillary layers 2 (2n2 %) and 3 (0n3 %). In capillary layer 1, the high observed total variation was due to a high biological variation among animals for the fractions of both Mu$ ller cell and non-Mu$ ller cell ensheathment. The rare occurrence of direct contacts between the capillary basal lamina and the perikarya of either microglial cells (capillary layer 3) or amacrine cells (capillary layer 2) corresponded well to the low stereological values obtained for the relative capillary surface ensheathed by non-Mu$ ller cells in these capillary layers. Previously, extensive and frequent contacts between the basal lamina of capillaries belonging to capillary layer 1 and horizontal cells had been observed in single sections. The present study quantitatively demonstrates a marked paucity of macroglial investment of capillaries located in capillary layer 1 of Tupaia. It can be concluded that horizontal cells ensheath most of the capillary surface not invested by Mu$ ller cells. In the retina of the adult tree shrew Tupaia belangeri, the basal lamina of capillaries located between the nerve fibre layer and the ganglion cell layer (capillary layer 4) is invested by the processes of Mu$ ller cells and by astrocytes which are absent from the outer parts of the retina. Retinal capillaries in the 3 outer capillary layers (capillary layers 1 to 3) are incompletely invested by the processes of Mu$ ller cells. To an extreme, the perikarya and the processes of horizontal cells abut on up to 90 % of the basal lamina of single capillary cross sections located between the outer

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Section: supporting

confidence: 55%

Section: mentioning

confidence: 89%

To what extent are the retinal capillaries ensheathed by Müller cells? A stereological study in the tree shrew Tupaia belangeri

2000

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“…The authors concluded that "Müller cells share the ability of astrocytes to induce the formation of barrier properties by vascular endothelial cells" and might, therefore, contribute to the formation of the inner blood-retina barrier (Tout et al 1993). Reichenbach et al (1995) provided the first detailed report of the structure and distribution of Müller cells in the retina of the tree shrew Tupaia belangeri. Tree shrews are basal eutherian mammals and their relationship to primates is under debate (Wible and Zeller 1994).…”

Section: Introductionmentioning

confidence: 98%

“…Tree shrews are basal eutherian mammals and their relationship to primates is under debate (Wible and Zeller 1994). Reichenbach et al (1995) have noted that, in Tupaia, "wherever blood vessels crossed through the INL (inner nuclear layer) or IPL (inner plexiform layer), they were surrounded by lamellar extensions of Müller cells". However, these authors did not focus on the structural properties of the inner blood-retina barrier.…”

Section: Introductionmentioning

confidence: 99%

Horizontal cells invest retinal capillaries in the tree shrew Tupaia belangeri

Knabe

Ochs

1999

Cell and Tissue Research

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Retinal capillaries were studied by transmission electron microscopy, immunohistochemistry and lectin histochemistry in the adult tree shrew Tupaia betangeri. In capillaries from all four vascular layers, adjacent endothelial cells were connected by tight junctions. Up to three layers of pericyte processes were embedded in the subendothelial basal lamina. However, pericytes frequently contacted the endothelial cells. In the innermost vascular layer (capillary layer 4), S-100-immunopositive astrocytes and the vitreal processes of S-100-immunopositive Muller cells entirely ensheathed the capillary basal lamina. However, capillaries revealing an incomplete macroglial investment were observed in the outer vascular layers, predominantly in capillary layers 1 and 2. In sections of capillaries located between the inner nuclear layer and the outer plexiform layer (capillary layer 1), these "gaps" were filled with the perikarya and electron-lucent processes of horizontal cells that ensheathed up to approximately nine tenths of the capillary circumference. Horizontal cells were identified by ultrastructural criteria. They were distinct from microglial cells by not being reactive for Griffonia simplicifolia isolectin-B4. In Tutpaia, vessel-contacting horizontal cells reside in a position reported to be occupied by the processes of Müller cells in other mammals. Current concepts of retinal function and pathology, which are based on the assumption that retinal vessels are strictly isolated from retinal neurons, at least in Tupaia, might deserve reconsideration.

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“…Cell culture media and supplements were from Invitrogen (Karlsruhe, Germany). Primary rat Müller cells and mouse RGCs were isolated and cultured as previously described [14,35]. Briefly, retinae from six-to nine-day-old Long-Evans rats were isolated and mechanically dissociated by careful homogenization.…”

Section: Animals and Cell Culturesmentioning

confidence: 99%

Müller Cell-Derived PEDF Mediates Neuroprotection via STAT3 Activation

Eichler¹,

Savkovic-Cvijic²,

Bürger³

et al. 2017

Cell Physiol Biochem

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Background/ Aims: This study was performed to reveal signaling pathways exploited by pigment epithelium-derived factor (PEDF) derived from retinal (glial) Müller cells to protect retinal ganglion cells (RGCs) from cell death. Methods: The survival of RGCs was determined in the presence of conditioned culture media (MCM) from or in co-cultures with Müller cells. The significance of PEDF-induced STAT3 activation was evaluated in viability assays and using Western blotting analyses and siRNA-transfected cells. Results: Secreted mediators of Müller cells increased survival of RGCs under normoxia or hypoxia to a similar degree as of PEDF-or IL-6-exposed cells. PEDF and MCM induced an increased STAT3 activation in RGCs and R28 cells, and neutralization of PEDF in MCM attenuated STAT3 activation. Inhibition of STAT3 reduced PEDF-promoted survival of RGCs. Similar to IL-6, PEDF induced STAT3 activation, acting in a dose-dependent manner via the PEDF receptor (PEDF-R) encoded by the PNPLA2 gene. Ablation of PEDF-R attenuated MCM-induced STAT3 activation and compromised the viability of PEDF-exposed R28 cells. Conclusions: Müller cells are an important source of PEDF, which promotes RGC survival through STAT3 activation and, at least in part, via PEDF-R. Enhancing the secretory function of Müller cells may be useful to promote RGC survival in retinal neurodegenerative diseases.

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Müller glial cells of the tree shrew retina

Cited by 31 publications

References 44 publications

To what extent are the retinal capillaries ensheathed by Müller cells? A stereological study in the tree shrew Tupaia belangeri

To what extent are the retinal capillaries ensheathed by Müller cells? A stereological study in the tree shrew Tupaia belangeri

Horizontal cells invest retinal capillaries in the tree shrew Tupaia belangeri

Müller Cell-Derived PEDF Mediates Neuroprotection via STAT3 Activation

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