AIM：To identify the pathological role of amyloid beta（Aβ） deposition in retinal degeneration,and explore Aβ deposition on the retinal pigment epithelium cells（RPE） layer and the associated structural and functi...AIM：To identify the pathological role of amyloid beta（Aβ） deposition in retinal degeneration,and explore Aβ deposition on the retinal pigment epithelium cells（RPE） layer and the associated structural and functional changes in Alzheimer＇s disease transgenic mice.METHODS：RPE changes in the eyes of APPswe/PS1 transgenic and none transgenic（NTG） mice over 20 months old were examined.Histological changes were investigated via hematoxylin and eosin（H＆E） staining and transmission electron microscopy（TEM） examination,whereas the expression of amyloid precursor protein（APP）,Aβ,Zonula occludens-1（ZO-1） and Ionized calcium binding adaptor molecule-1（IBA-1） were investigated using immunohistochemistry and immunofluorescence techniques.All of the obtained results were quantitatively and statistically analyzed.RESULTS：In aged transgenic mice,an APP-positive immunoreaction and Aβ deposition were detected on the RPE layer but were undetectable in NTG mice.The RPE demonstrated some vacuole changes,shortened basal infoldings and basal deposition in histopathological examination and TEM tests,wherein irregular shapes were indicated by ZO-1 disorganization through fluorescence.Furthermore,IBA-1 positive cells were observed to have accumulated and infiltrated into the RPE layer and localized beneath the RPE/Bruch＇s membrane（Br M） complex,which was accompanied by an increase in BrM thickness in aged transgenic mice in comparison to NTG mice.The IBA-1 positive cells were found to be co-stained with Aβ deposition on the RPE flat mounts.CONCLUSION：The observed Aβ deposition in the RPE layer may cause RPE dysfunction,which is associated with microglia cells infiltration into the retina of aged transgenic mice,suggesting that Aβ deposition probably plays a significant role in RPE-related degenerative disease.展开更多
Several studies have investigated the protective functions of brain-derived neurotrophic factor（BDNF） in retinitis pigmentosa. However, a BDNF-based therapy for retinitis pigmentosa is not yet available. To develop ...Several studies have investigated the protective functions of brain-derived neurotrophic factor（BDNF） in retinitis pigmentosa. However, a BDNF-based therapy for retinitis pigmentosa is not yet available. To develop an efficient treatment for fundus disease, an eukaryotic expression plasmid was generated and used to transfect human 293 T cells to assess the expression and bioactivity of BDNF on acute retinal pigment epithelial-19（ARPE-19） cells, a human retinal epithelial cell line. After 96 hours of co-culture in a Transwell chamber, ARPE-19 cells exposed to BDNF secreted by 293 T cells were more viable than ARPE-19 cells not exposed to secreted BDNF. Western blot assay showed that Bax levels were downregulated and that Bcl-2 levels were upregulated in human ARPE-19 cells exposed to BDNF. Furthermore, 293 T cells transfected with the BDNF gene steadily secreted the protein. The powerful anti-apoptotic function of this BDNF may be useful for the treatment of retinitis pigmentosa and other retinal degenerative diseases.展开更多
Organogenesis is regulated by a complex network of intrinsic cues, diffusible signals and cell/cell or cell/matrix interactions that drive the cells of a prospective organ to differentiate and collectively organize in...Organogenesis is regulated by a complex network of intrinsic cues, diffusible signals and cell/cell or cell/matrix interactions that drive the cells of a prospective organ to differentiate and collectively organize in three dimensions. Generating organs in vitro from embryonic stem (ES) cells may provide a simplified system to decipher how these processes are orchestrated in time and space within particular and between neighboring tissues. Recently, this field of stem cell research has also gained considerable interest for its potential applications in regenerative medicine. Among human pathologies for which stem cell-based therapy is foreseen as a promising therapeutic strategy are many retinal degenerative diseases, like retinitis pigmentosa and age-related macular degeneration. Over the last decade, progress has been made in producing ES-derived retinal cells in vitro, but engineering entire synthetic retinas was considered beyond reach. Recently however, major breakthroughs have been achieved with pioneer works describing the extraordinary self-organization of murine and human ES cells into a three dimensional structure highly resembling a retina. ES-derived retinal cells indeed assemble to form a cohesive neuroepithelial sheet that is endowed with the intrinsic capacity to recapitulate, outside an embryonic environment, the main steps of retinal morphogenesis as observed in vivo. This represents a tremendous advance that should help resolving fundamental questions related to retinogenesis. Here, we will discuss these studies, and the potential applications of such stem cell-based systems for regenerative medicine.展开更多
The timely and efficient elimination of aberrant proteins and damaged organelles, formed in response to various genetic and environmental stressors, is a vital need for all cells of the body. Recent lines of evidence ...The timely and efficient elimination of aberrant proteins and damaged organelles, formed in response to various genetic and environmental stressors, is a vital need for all cells of the body. Recent lines of evidence point out several non-classical strategies employed by ocular tissues to cope with aberrant constituents generated in the retina and in the retinal pigmented epithelium cells exposed to various stressors. Along with conventional strategies relying upon the intracellular degradation of aberrant constituents through ubiquitin-proteasome and/or lysosome-dependent autophagy proteolysis, two non-conventional mechanisms also contribute to proteostasis maintenance in ocular tissues. An exosome-mediated clearing and a myelinosome-driven secretion mechanism do not require intracellular degradation but provide the export of aberrant constituents and “waste proteins” outside of the cells. The current review is centered on the non-degradative myelinosome-driven secretion mechanism, which operates in the retina of transgenic Huntington’s disease R6/1 model mice. Myelinosome-driven secretion is supported by rare organelles myelinosomes that are detected not only in degenerative Huntington’s disease R6/1 retina but also in various pathological states of the retina and of the retinal pigmented epithelium. The intra-retinal traffic and inter-cellular exchange of myelinosomes was discussed in the context of a dual role of the myelinosome-driven secretion mechanism for proteostasis maintenance in different ocular compartments. Special focus was made on the interplay between degradative and non-degradative strategies in ocular pathophysiology, to delineate potential therapeutic approaches to counteract several vision diseases.展开更多
BACKGROUND Adipose-derived stem cells(ASCs)have been increasingly explored for cell-based medicine because of their numerous advantages in terms of easy availability,high proliferation rate,multipotent differentiation...BACKGROUND Adipose-derived stem cells(ASCs)have been increasingly explored for cell-based medicine because of their numerous advantages in terms of easy availability,high proliferation rate,multipotent differentiation ability and low immunogenicity.In this respect,they have been widely investigated in the last two decades to develop therapeutic strategies for a variety of human pathologies including eye disease.In ocular diseases involving the retina,various cell types may be affected,such as Müller cells,astrocytes,photoreceptors and retinal pigment epithelium(RPE),which plays a fundamental role in the homeostasis of retinal tissue,by secreting a variety of growth factors that support retinal cells.AIM To test ASC neural differentiation using conditioned medium(CM)from an RPE cell line(ARPE-19).METHODS ASCs were isolated from adipose tissue,harvested from the subcutaneous region of healthy donors undergoing liposuction procedures.Four ASC culture conditions were investigated:ASCs cultured in basal Dulbecco's Modified Eagle Medium(DMEM);ASCs cultured in serum-free DMEM;ASCs cultured in serumfree DMEM/F12;and ASCs cultured in a CM from ARPE-19,a spontaneously arising cell line with a normal karyotype derived from a human RPE.Cell proliferation rate and viability were assessed by crystal violet and MTT assays at 1,4and 8 d of culture.At the same time points,ASC neural differentiation was evaluated by immunocytochemistry and western blot analysis for typical neuronal and glial markers:Nestin,neuronal specific enolase(NSE),protein gene product(PGP)9.5,and glial fibrillary acidic protein(GFAP).RESULTS Depending on the culture medium,ASC proliferation rate and viability showed some significant differences.Overall,less dense populations were observed in serum-free cultures,except for ASCs cultured in ARPE-19 serum-free CM.Moreover,a different cell morphology was seen in these cultures after 8 d of treatment,with more elongated cells,often showing cytoplasmic ramifications.Immunofluorescence results and western blot analysis were indicative of ASC neural differentiation.In fact,basal levels of neural markers detected under control conditions significantly increased when cells were cultured in ARPE-19 CM.Specifically,neural marker overexpression was more marked at 8 d.The most evident increase was observed for NSE and GFAP,a modest increase was observed for nestin,and less relevant changes were observed for PGP9.5.CONCLUSION The presence of growth factors produced by ARPE-19 cells in tissue culture induces ASCs to express neural differentiation markers typical of the neuronal and glial cells of the retina.展开更多
Background The human immunodeficiency virus-1 （HIV-1） envelope glycoprotein gp120 has been implicated in the development of AIDS-associated retinopathy. The present study tested the hypothesis that gp120 may induce ...Background The human immunodeficiency virus-1 （HIV-1） envelope glycoprotein gp120 has been implicated in the development of AIDS-associated retinopathy. The present study tested the hypothesis that gp120 may induce oxidative stress including up regulation of inducible nitric oxide synthase （iNOS） and production of malondialdehyde （MDA） and nitric oxide （NO） to mediate retinopathy in retinal pigment epithelial （RPE） cells. Methods Human RPE cell line D407 was cultured and treated with gp120. HIV-1 gp120 protein induced lipid peroxidation product MDA. NO production and iNOS expression were examined in vitro by spectrophomtometry, real-time PCR, Western blotting, and confocal microscope. Results Addition of gp120 was able to induce RPE cells to produce NO and MDA in time- and dose-dependent manners （P 〈0.05）. Similarly, gp120 was also capable of up-regulating iNOS mRNA and protein in D407 cells in time- and dose-dependent manners. Conclusions Gp120 induces oxidative stress in D407 cell by stimulating MDA and NO production, which is mediated by up-regulating iNOS expression. Gp120 may mediate oxidation stress in AIDS-associated retinopathy.展开更多
基金Supported by the National Natural Science Foundation of China(No.81430009No.81400424)the Science and Technology Research and Development Project of Shaanxi Province(No.2014K11-03-07-04)
文摘AIM：To identify the pathological role of amyloid beta（Aβ） deposition in retinal degeneration,and explore Aβ deposition on the retinal pigment epithelium cells（RPE） layer and the associated structural and functional changes in Alzheimer＇s disease transgenic mice.METHODS：RPE changes in the eyes of APPswe/PS1 transgenic and none transgenic（NTG） mice over 20 months old were examined.Histological changes were investigated via hematoxylin and eosin（H＆E） staining and transmission electron microscopy（TEM） examination,whereas the expression of amyloid precursor protein（APP）,Aβ,Zonula occludens-1（ZO-1） and Ionized calcium binding adaptor molecule-1（IBA-1） were investigated using immunohistochemistry and immunofluorescence techniques.All of the obtained results were quantitatively and statistically analyzed.RESULTS：In aged transgenic mice,an APP-positive immunoreaction and Aβ deposition were detected on the RPE layer but were undetectable in NTG mice.The RPE demonstrated some vacuole changes,shortened basal infoldings and basal deposition in histopathological examination and TEM tests,wherein irregular shapes were indicated by ZO-1 disorganization through fluorescence.Furthermore,IBA-1 positive cells were observed to have accumulated and infiltrated into the RPE layer and localized beneath the RPE/Bruch＇s membrane（Br M） complex,which was accompanied by an increase in BrM thickness in aged transgenic mice in comparison to NTG mice.The IBA-1 positive cells were found to be co-stained with Aβ deposition on the RPE flat mounts.CONCLUSION：The observed Aβ deposition in the RPE layer may cause RPE dysfunction,which is associated with microglia cells infiltration into the retina of aged transgenic mice,suggesting that Aβ deposition probably plays a significant role in RPE-related degenerative disease.
基金supported by the National Natural Science Foundation of China,No.81271046the Joint Program of Beijing Municipal Natural Science Foundation(category B)Beijing Educational Committee(key project),No.KZ201510025025
文摘Several studies have investigated the protective functions of brain-derived neurotrophic factor（BDNF） in retinitis pigmentosa. However, a BDNF-based therapy for retinitis pigmentosa is not yet available. To develop an efficient treatment for fundus disease, an eukaryotic expression plasmid was generated and used to transfect human 293 T cells to assess the expression and bioactivity of BDNF on acute retinal pigment epithelial-19（ARPE-19） cells, a human retinal epithelial cell line. After 96 hours of co-culture in a Transwell chamber, ARPE-19 cells exposed to BDNF secreted by 293 T cells were more viable than ARPE-19 cells not exposed to secreted BDNF. Western blot assay showed that Bax levels were downregulated and that Bcl-2 levels were upregulated in human ARPE-19 cells exposed to BDNF. Furthermore, 293 T cells transfected with the BDNF gene steadily secreted the protein. The powerful anti-apoptotic function of this BDNF may be useful for the treatment of retinitis pigmentosa and other retinal degenerative diseases.
文摘Organogenesis is regulated by a complex network of intrinsic cues, diffusible signals and cell/cell or cell/matrix interactions that drive the cells of a prospective organ to differentiate and collectively organize in three dimensions. Generating organs in vitro from embryonic stem (ES) cells may provide a simplified system to decipher how these processes are orchestrated in time and space within particular and between neighboring tissues. Recently, this field of stem cell research has also gained considerable interest for its potential applications in regenerative medicine. Among human pathologies for which stem cell-based therapy is foreseen as a promising therapeutic strategy are many retinal degenerative diseases, like retinitis pigmentosa and age-related macular degeneration. Over the last decade, progress has been made in producing ES-derived retinal cells in vitro, but engineering entire synthetic retinas was considered beyond reach. Recently however, major breakthroughs have been achieved with pioneer works describing the extraordinary self-organization of murine and human ES cells into a three dimensional structure highly resembling a retina. ES-derived retinal cells indeed assemble to form a cohesive neuroepithelial sheet that is endowed with the intrinsic capacity to recapitulate, outside an embryonic environment, the main steps of retinal morphogenesis as observed in vivo. This represents a tremendous advance that should help resolving fundamental questions related to retinogenesis. Here, we will discuss these studies, and the potential applications of such stem cell-based systems for regenerative medicine.
文摘The timely and efficient elimination of aberrant proteins and damaged organelles, formed in response to various genetic and environmental stressors, is a vital need for all cells of the body. Recent lines of evidence point out several non-classical strategies employed by ocular tissues to cope with aberrant constituents generated in the retina and in the retinal pigmented epithelium cells exposed to various stressors. Along with conventional strategies relying upon the intracellular degradation of aberrant constituents through ubiquitin-proteasome and/or lysosome-dependent autophagy proteolysis, two non-conventional mechanisms also contribute to proteostasis maintenance in ocular tissues. An exosome-mediated clearing and a myelinosome-driven secretion mechanism do not require intracellular degradation but provide the export of aberrant constituents and “waste proteins” outside of the cells. The current review is centered on the non-degradative myelinosome-driven secretion mechanism, which operates in the retina of transgenic Huntington’s disease R6/1 model mice. Myelinosome-driven secretion is supported by rare organelles myelinosomes that are detected not only in degenerative Huntington’s disease R6/1 retina but also in various pathological states of the retina and of the retinal pigmented epithelium. The intra-retinal traffic and inter-cellular exchange of myelinosomes was discussed in the context of a dual role of the myelinosome-driven secretion mechanism for proteostasis maintenance in different ocular compartments. Special focus was made on the interplay between degradative and non-degradative strategies in ocular pathophysiology, to delineate potential therapeutic approaches to counteract several vision diseases.
基金Supported by University of Catania,Italy,“Piano Triennale per la Ricerca 2020-2022–Grant PIACERI,project“NanoRet””.
文摘BACKGROUND Adipose-derived stem cells(ASCs)have been increasingly explored for cell-based medicine because of their numerous advantages in terms of easy availability,high proliferation rate,multipotent differentiation ability and low immunogenicity.In this respect,they have been widely investigated in the last two decades to develop therapeutic strategies for a variety of human pathologies including eye disease.In ocular diseases involving the retina,various cell types may be affected,such as Müller cells,astrocytes,photoreceptors and retinal pigment epithelium(RPE),which plays a fundamental role in the homeostasis of retinal tissue,by secreting a variety of growth factors that support retinal cells.AIM To test ASC neural differentiation using conditioned medium(CM)from an RPE cell line(ARPE-19).METHODS ASCs were isolated from adipose tissue,harvested from the subcutaneous region of healthy donors undergoing liposuction procedures.Four ASC culture conditions were investigated:ASCs cultured in basal Dulbecco's Modified Eagle Medium(DMEM);ASCs cultured in serum-free DMEM;ASCs cultured in serumfree DMEM/F12;and ASCs cultured in a CM from ARPE-19,a spontaneously arising cell line with a normal karyotype derived from a human RPE.Cell proliferation rate and viability were assessed by crystal violet and MTT assays at 1,4and 8 d of culture.At the same time points,ASC neural differentiation was evaluated by immunocytochemistry and western blot analysis for typical neuronal and glial markers:Nestin,neuronal specific enolase(NSE),protein gene product(PGP)9.5,and glial fibrillary acidic protein(GFAP).RESULTS Depending on the culture medium,ASC proliferation rate and viability showed some significant differences.Overall,less dense populations were observed in serum-free cultures,except for ASCs cultured in ARPE-19 serum-free CM.Moreover,a different cell morphology was seen in these cultures after 8 d of treatment,with more elongated cells,often showing cytoplasmic ramifications.Immunofluorescence results and western blot analysis were indicative of ASC neural differentiation.In fact,basal levels of neural markers detected under control conditions significantly increased when cells were cultured in ARPE-19 CM.Specifically,neural marker overexpression was more marked at 8 d.The most evident increase was observed for NSE and GFAP,a modest increase was observed for nestin,and less relevant changes were observed for PGP9.5.CONCLUSION The presence of growth factors produced by ARPE-19 cells in tissue culture induces ASCs to express neural differentiation markers typical of the neuronal and glial cells of the retina.
基金This study was supported by a grant from the National Natural Science Foundation of China （No. 30471851）.Acknowledgements： We are grateful to the AIDS Research and Reference Reagent Program, Division of AIDS, NIAID, NIH for offering us HIV-1 gp120.
文摘Background The human immunodeficiency virus-1 （HIV-1） envelope glycoprotein gp120 has been implicated in the development of AIDS-associated retinopathy. The present study tested the hypothesis that gp120 may induce oxidative stress including up regulation of inducible nitric oxide synthase （iNOS） and production of malondialdehyde （MDA） and nitric oxide （NO） to mediate retinopathy in retinal pigment epithelial （RPE） cells. Methods Human RPE cell line D407 was cultured and treated with gp120. HIV-1 gp120 protein induced lipid peroxidation product MDA. NO production and iNOS expression were examined in vitro by spectrophomtometry, real-time PCR, Western blotting, and confocal microscope. Results Addition of gp120 was able to induce RPE cells to produce NO and MDA in time- and dose-dependent manners （P 〈0.05）. Similarly, gp120 was also capable of up-regulating iNOS mRNA and protein in D407 cells in time- and dose-dependent manners. Conclusions Gp120 induces oxidative stress in D407 cell by stimulating MDA and NO production, which is mediated by up-regulating iNOS expression. Gp120 may mediate oxidation stress in AIDS-associated retinopathy.
