Effect of Sugars on Photoreceptor Outer Segment Assembly

Stiemke, Monica M.; Hollyfield, Joe G.

doi:10.1007/978-1-4615-1897-6_15

Cited by 10 publications

(5 citation statements)

References 13 publications

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“…Our data suggest that, in conditions in which Mü ller cell function is compromised, photoreceptor dysmorphogenesis can result. Such conditions include retinal dystrophies induced by mutations in genes expressed in Mü ller cells (Maw et al, 1997;Kennedy et al, 1999) or degenerative conditions in which the cause lies outside the Mü ller cell, yet in which Mü ller cell function is adversely affected (Erickson et al, 1983;Anderson et al, 1986;Guérin et al, 1989Guérin et al, , 1993Faktorovich et al, 1990;Lewis et al, 1991;Stiemke and Hollyfield, 1995). We propose that the structural and supportive relationship between Mü ller cells and photoreceptor may be an important factor in modulating further photoreceptor loss in degenerating retinas and should be closely evaluated in RP and allied diseases.…”

Section: Discussionmentioning

confidence: 99%

Targeted disruption of M�ller cell metabolism induces photoreceptor dysmorphogenesis

Jablonski

Iannaccone

2000

Glia

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Section: Discussionmentioning

confidence: 99%

Targeted disruption of M�ller cell metabolism induces photoreceptor dysmorphogenesis

Jablonski

Iannaccone

2000

Glia

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“…In the absence of the RPE, retinal degeneration, phenotypically characterized by cone and rod outer segment disorganization, occurs (Stiemke and Hollyfield, 1994; Stiemke et al, 1994; Jablonski et al, 1999; Jablonski and Ervin, 2000; Jablonski and Iannaccone, 2000a,b). Our laboratory has also demonstrated that lactose protects against the degeneration that is induced by RPE removal by supporting the proper folding of outer segment membranes (Stiemke and Hollyfield, 1994, 1995; Jablonski et al, 1999; Jablonski and Ervin, 2000) and preserving the protein expression patterns of opsin and rds /peripherin in photoreceptors (Jablonski et al, 1999).…”

mentioning

confidence: 99%

Downregulation of a unique photoreceptor protein correlates with improper outer segment assembly

Wohabrebbi

Umstot

Iannaccone

et al. 2002

J of Neuroscience Research

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A unique photoreceptor protein has been characterized. This protein, termed XAP-1 antigen, is expressed by photoreceptors exclusively under conditions in which the outer segment membranes are properly assembled. When the retinal pigment epithelium is adherent to the underlying neural retina, the XAP-1 antigen is localized to the plasma membrane that surrounds the inner and outer segments in the areas juxtaposed to the subretinal space. A similar labeling pattern is detected in retinal pigment epithelium-deprived retinas in which assembly of nascent outer segments is supported by lactose. In retinas that undergo degeneration subsequent to the removal of the retinal pigment epithelium, the expression of this protein is completely downregulated. Immunohistochemical analyses and subcellular fractionation along with Western blot analysis, indicate that the XAP-1 antigen is a membrane-associated soluble protein. Mass spectrometric analysis indicates that the XAP-1 antigen shares homology via 12 tryptic peptide masses with the gamma-crystallin (lens structural protein) subclasses, although it does not immunolocalize to the same ocular structures as reported for the gamma-crystallins. We propose that XAP-1 antigen is a unique protein that is expressed extensively by healthy photoreceptor cells; the expression of the XAP-1 antigen exclusively by photoreceptors with organized outer segments suggests that this protein may play a critical role in outer segment assembly.

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“…We have previously demonstrated that both the neurotrophic agent, PEDF , and permissive glycans including lactose, galactose and IPTG (Jablonski and Ervin, 2000;Stiemke and Hollyfield, 1995;Wang et al, 2003) Rport photoreceptor outer segment assembly in isolated RPE-deprived Xenopus laevis eye rudiments. We have also previously demonstrated that Müller cells are likely directly involved in the process of photoreceptor outer segment assembly .…”

Section: Discussionmentioning

confidence: 96%

“…Similarly, lactose, galactose, isopropyl beta-D-thiogalactoside (i.e. IPTG, a non-metabolizable form of galactose), and structurallyrelated glycans also support photoreceptor outer segment assembly in RPE-deprived Xenopus retinas Stiemke and Hollyfield, 1995;Jablonski et al, 1999;Jablonski and Ervin, 2000) through a mechanism that appears to be receptor-mediated (Wang et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Contribution of Müller cells toward the regulation of photoreceptor outer segment assembly

2004

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The assembly of photoreceptor outer segments into stacked discs is a complicated process, the precise regulation of which remains a mystery. It is known that the integrity of the outer segment is heavily dependent upon surrounding cell types including the retinal pigment epithelium and Müller cells; however the role played by Müller cells within this photoreceptor-specific process has not been fully explored. Using an RPE-deprived but otherwise intact Xenopus laevis eye rudiment preparation, we reveal that Müller cell involvement in outer segment assembly is dependent upon the stimulus provided to the retina. Pigment epithelium-derived factor is able to support proper membrane folding after inhibition of Müller cell metabolism by alpha-aminoadipic acid, while isopropyl beta-Dthiogalactoside, a permissive glycan, requires intact Müller cell function. These results demonstrate that both intrinsic and extrinsic redundant mechanisms exist to support the ability of photoreceptors to properly assemble their outer segments. Our study further suggests that the receptor for pigment epithelium-derived factor resides in photoreceptors themselves while that for permissive glycans is likely localized to Müller cells, which in turn communicate with photoreceptors to promote proper membrane assembly.

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Effect of Sugars on Photoreceptor Outer Segment Assembly

Cited by 10 publications

References 13 publications

Targeted disruption of M�ller cell metabolism induces photoreceptor dysmorphogenesis

Targeted disruption of M�ller cell metabolism induces photoreceptor dysmorphogenesis

Downregulation of a unique photoreceptor protein correlates with improper outer segment assembly

Contribution of Müller cells toward the regulation of photoreceptor outer segment assembly

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