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Ubiquitous presence of gluconeogenic regulatory enzyme, fructose-1,6-bisphosphatase, within layers of rat retina.

Mamczur P, Mazurek J, Rakus D - Cell Tissue Res. (2010)

Bottom Line: The abundance of the enzyme within the layers of the rat retina suggests that, in mammals in contrast to amphibia, gluconeogenesis is not restricted to one specific cell of the retina.We propose that FBPase, in addition to its gluconeogenic role, participates in the protection of the retina against reactive oxygen species.Additionally, the nuclear localization of FBPase and of its binding partner, aldolase, in the retinal cells expressing the proliferation marker Ki-67 indicates that these two gluconeogenic enzymes are involved in non-enzymatic nuclear processes.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal Molecular Physiology, Institute of Zoology, Wroclaw University, Cybulskiego 30, 50-205, Wroclaw, Poland.

ABSTRACT
To shed some light on gluconeogenesis in mammalian retina, we have focused on fructose-1,6-bisphosphatase (FBPase), a regulatory enzyme of the process. The abundance of the enzyme within the layers of the rat retina suggests that, in mammals in contrast to amphibia, gluconeogenesis is not restricted to one specific cell of the retina. We propose that FBPase, in addition to its gluconeogenic role, participates in the protection of the retina against reactive oxygen species. Additionally, the nuclear localization of FBPase and of its binding partner, aldolase, in the retinal cells expressing the proliferation marker Ki-67 indicates that these two gluconeogenic enzymes are involved in non-enzymatic nuclear processes.

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Presence of FBPase in cytoplasm of Müller cells. Double-immunofluorescent staining of isolated Müller cells with antibodies against vimentin (a), FBPase (b, e), and α-tubulin (d). c, f Merged images from, respectively, a, b or from d, e. Nuclei were counterstained with DAPI. Bar 50 μm
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Fig3: Presence of FBPase in cytoplasm of Müller cells. Double-immunofluorescent staining of isolated Müller cells with antibodies against vimentin (a), FBPase (b, e), and α-tubulin (d). c, f Merged images from, respectively, a, b or from d, e. Nuclei were counterstained with DAPI. Bar 50 μm

Mentions: To identify which cell populations within the rat retina expressed FBPase, we used immunofluorescence techniques and confocal microscopy. In radial sections of the rat retina, the use of antiserum against muscle FBPase revealed immunoreactivity within several layers: within the inner plexiform layer (IPL), outer plexiform layer (OPL), and outer limiting membrane and within the inner segments of photoreceptors (Fig. 2). Double-labeling with antibodies against α-tubulin (Fig. 2a-d), aldolase A (Fig. 2e-h), or GFAP (Fig. 2i-l) in combination with antibodies directed against FBPase demonstrated at least partial co-localization of FBPase with these proteins. The FBPase fluorescence was particularly visible in the radially aligned elements of the retina suggesting that the enzyme was localized mainly in the Müller cells. Indeed, freshly isolated rat Müller cells treated with antibodies against vimentin, a specific marker of these cells (Guidry 1996; Ishii et al. 1997), showed relatively strong immunofluorescent signals for FBPase (Fig. 3). However, other than the Müller cells, strong FBPase-related immunoreactivity was also found in retinal astrocytes in which FBPase appeared to be co-localized with α-tubulin (Fig. 4).Fig. 2


Ubiquitous presence of gluconeogenic regulatory enzyme, fructose-1,6-bisphosphatase, within layers of rat retina.

Mamczur P, Mazurek J, Rakus D - Cell Tissue Res. (2010)

Presence of FBPase in cytoplasm of Müller cells. Double-immunofluorescent staining of isolated Müller cells with antibodies against vimentin (a), FBPase (b, e), and α-tubulin (d). c, f Merged images from, respectively, a, b or from d, e. Nuclei were counterstained with DAPI. Bar 50 μm
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Related In: Results  -  Collection

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Fig3: Presence of FBPase in cytoplasm of Müller cells. Double-immunofluorescent staining of isolated Müller cells with antibodies against vimentin (a), FBPase (b, e), and α-tubulin (d). c, f Merged images from, respectively, a, b or from d, e. Nuclei were counterstained with DAPI. Bar 50 μm
Mentions: To identify which cell populations within the rat retina expressed FBPase, we used immunofluorescence techniques and confocal microscopy. In radial sections of the rat retina, the use of antiserum against muscle FBPase revealed immunoreactivity within several layers: within the inner plexiform layer (IPL), outer plexiform layer (OPL), and outer limiting membrane and within the inner segments of photoreceptors (Fig. 2). Double-labeling with antibodies against α-tubulin (Fig. 2a-d), aldolase A (Fig. 2e-h), or GFAP (Fig. 2i-l) in combination with antibodies directed against FBPase demonstrated at least partial co-localization of FBPase with these proteins. The FBPase fluorescence was particularly visible in the radially aligned elements of the retina suggesting that the enzyme was localized mainly in the Müller cells. Indeed, freshly isolated rat Müller cells treated with antibodies against vimentin, a specific marker of these cells (Guidry 1996; Ishii et al. 1997), showed relatively strong immunofluorescent signals for FBPase (Fig. 3). However, other than the Müller cells, strong FBPase-related immunoreactivity was also found in retinal astrocytes in which FBPase appeared to be co-localized with α-tubulin (Fig. 4).Fig. 2

Bottom Line: The abundance of the enzyme within the layers of the rat retina suggests that, in mammals in contrast to amphibia, gluconeogenesis is not restricted to one specific cell of the retina.We propose that FBPase, in addition to its gluconeogenic role, participates in the protection of the retina against reactive oxygen species.Additionally, the nuclear localization of FBPase and of its binding partner, aldolase, in the retinal cells expressing the proliferation marker Ki-67 indicates that these two gluconeogenic enzymes are involved in non-enzymatic nuclear processes.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal Molecular Physiology, Institute of Zoology, Wroclaw University, Cybulskiego 30, 50-205, Wroclaw, Poland.

ABSTRACT
To shed some light on gluconeogenesis in mammalian retina, we have focused on fructose-1,6-bisphosphatase (FBPase), a regulatory enzyme of the process. The abundance of the enzyme within the layers of the rat retina suggests that, in mammals in contrast to amphibia, gluconeogenesis is not restricted to one specific cell of the retina. We propose that FBPase, in addition to its gluconeogenic role, participates in the protection of the retina against reactive oxygen species. Additionally, the nuclear localization of FBPase and of its binding partner, aldolase, in the retinal cells expressing the proliferation marker Ki-67 indicates that these two gluconeogenic enzymes are involved in non-enzymatic nuclear processes.

Show MeSH