The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Masasuke Araki - One of the best experts on this subject based on the ideXlab platform.
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Change in the developmental fate of the chick Optic Vesicle from the neural retina to the telencephalon.
Development growth & differentiation, 2019Co-Authors: Misaki Shirahama, Ichie Steinfeld, Astrid Vogel-höpker, Paul G. Layer, Akari Karaiwa, Shigeru Taketani, Masasuke ArakiAbstract:The forebrain develops into the telencephalon, diencephalon, and Optic Vesicle (OV). The OV further develops into the Optic cup, the inner and outer layers of which develop into the neural retina and retinal pigmented epithelium (RPE), respectively. We studied the change in fate of the OV by using embryonic transplantation and explant culture methods. OVs excised from 10-somite stage chick embryos were freed from surrounding tissues (the surface ectoderm and mesenchyme) and were transplanted back to their original position in host embryos. Expression of neural retina-specific genes, such as Rax and Vsx2 (Chx10), was downregulated in the transplants. Instead, expression of the telencephalon-specific gene Emx1 emerged in the proximal region of the transplants, and in the distal part of the transplants close to the epidermis, expression of an RPE-specific gene Mitf was observed. Explant culture studies showed that when OVs were cultured alone, Rax was continuously expressed regardless of surrounding tissues (mesenchyme and epidermis). When OVs without surrounding tissues were cultured in close contact with the anterior forebrain, Rax expression became downregulated in the explants, and Emx1 expression became upregulated. These findings indicate that chick OVs at stage 10 are bi-potential with respect to their developmental fates, either for the neural retina or for the telencephalon, and that the surrounding tissues have a pivotal role in their actual fates. An in vitro tissue culture model suggests that under the influence of the anterior forebrain and/or its surrounding tissues, the OV changes its fate from the retina to the telencephalon.
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rpe specification in the chick is mediated by surface ectoderm derived bmp and wnt signalling
Development, 2013Co-Authors: Jorg Steinfeld, Ichie Steinfeld, Nicola Coronato, Meggilee Hampel, Masasuke Araki, Paul G. Layer, Astrid VogelhopkerAbstract:The retinal pigment epithelium (RPE) is indispensable for vertebrate eye development and vision. In the classical model of Optic Vesicle patterning, the surface ectoderm produces fibroblast growth factors (FGFs) that specify the neural retina (NR) distally, whereas TGFβ family members released from the proximal mesenchyme are involved in RPE specification. However, we previously proposed that bone morphogenetic proteins (BMPs) released from the surface ectoderm are essential for RPE specification in chick. We now show that the BMP- and Wnt-expressing surface ectoderm is required for RPE specification. We reveal that Wnt signalling from the overlying surface ectoderm is involved in restricting BMP-mediated RPE specification to the dorsal Optic Vesicle. Wnt2b is expressed in the dorsal surface ectoderm and subsequently in dorsal Optic Vesicle cells. Activation of Wnt signalling by implanting Wnt3a-soaked beads or inhibiting GSK3β at Optic Vesicle stages inhibits NR development and converts the entire Optic Vesicle into RPE. Surface ectoderm removal at early Optic Vesicle stages or inhibition of Wnt, but not Wnt/β-catenin, signalling prevents pigmentation and downregulates the RPE regulatory gene Mitf. Activation of BMP or Wnt signalling can replace the surface ectoderm to rescue MITF expression and Optic cup formation. We provide evidence that BMPs and Wnts cooperate via a GSK3β-dependent but β-catenin-independent pathway at the level of pSmad to ensure RPE specification in dorsal Optic Vesicle cells. We propose a new dorsoventral model of Optic Vesicle patterning, whereby initially surface ectoderm-derived Wnt signalling directs dorsal Optic Vesicle cells to develop into RPE through a stabilising effect of BMP signalling.
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coordinated regulation of dorsal bone morphogenetic protein 4 and ventral sonic hedgehog signaling specifies the dorso ventral polarity in the Optic Vesicle and governs ocular morphogenesis through fibroblast growth factor 8 upregulation
Development Growth & Differentiation, 2010Co-Authors: Takuma Kobayashi, Kunio Yasuda, Masasuke ArakiAbstract:Dorsal and ventral specification in the early Optic Vesicle plays a crucial role in vertebrate ocular morphogenesis, and proper dorsal-ventral polarity in the Optic Vesicle ensures that distinct structures develop in separate domains within the eye primordium. The polarity is determined progressively during development by coordinated regulation of extraocular dorsal and ventral factors. In the present study, we cultured discrete portions of embryonic chick brains by preparing anterior cephalon, anterior dorsal cephalon and anterior ventral cephalon, and clearly demonstrate that bone morphogenetic protein 4 (BMP4) and Sonic hedgehog (Shh) constitute a dorsal-ventral signaling system together with fibroblast growth factor 8 (FGF8). BMP4 and Shh upregulate Tbx5 and Pax2, as reported previously, and at the same time Shh downregulates Tbx5, while BMP4 affects Pax2 expression to downregulate similarly. Shh induces Fgf8 expression in the ventral Optic Vesicle. This, in turn, determines the distinct boundary of the retinal pigmented epithelium and the neural retina by suppressing Mitf expression. The lens develops only when signals from both the dorsal and ventral regions come across together. Inverted deposition of Shh and BMP4 signals in organ-cultured Optic Vesicle completely re-organized ocular structures to be inverted. Based on these observations we propose a novel model in which the two signals govern the whole of ocular development when they encounter each other in the ocular morphogenic domain.
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Coordinated regulation of dorsal bone morphogenetic protein 4 and ventral Sonic hedgehog signaling specifies the dorso‐ventral polarity in the Optic Vesicle and governs ocular morphogenesis through fibroblast growth factor 8 upregulation
Development growth & differentiation, 2010Co-Authors: Takuma Kobayashi, Kunio Yasuda, Masasuke ArakiAbstract:Dorsal and ventral specification in the early Optic Vesicle plays a crucial role in vertebrate ocular morphogenesis, and proper dorsal-ventral polarity in the Optic Vesicle ensures that distinct structures develop in separate domains within the eye primordium. The polarity is determined progressively during development by coordinated regulation of extraocular dorsal and ventral factors. In the present study, we cultured discrete portions of embryonic chick brains by preparing anterior cephalon, anterior dorsal cephalon and anterior ventral cephalon, and clearly demonstrate that bone morphogenetic protein 4 (BMP4) and Sonic hedgehog (Shh) constitute a dorsal-ventral signaling system together with fibroblast growth factor 8 (FGF8). BMP4 and Shh upregulate Tbx5 and Pax2, as reported previously, and at the same time Shh downregulates Tbx5, while BMP4 affects Pax2 expression to downregulate similarly. Shh induces Fgf8 expression in the ventral Optic Vesicle. This, in turn, determines the distinct boundary of the retinal pigmented epithelium and the neural retina by suppressing Mitf expression. The lens develops only when signals from both the dorsal and ventral regions come across together. Inverted deposition of Shh and BMP4 signals in organ-cultured Optic Vesicle completely re-organized ocular structures to be inverted. Based on these observations we propose a novel model in which the two signals govern the whole of ocular development when they encounter each other in the ocular morphogenic domain.
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Generation of a second eye by embryonic transplantation of the antero‐ventral hemicephalon
Development growth & differentiation, 2009Co-Authors: Takuma Kobayashi, Kunio Yasuda, Masasuke ArakiAbstract:Vertebrate ocular morphogenesis requires proper dorso-ventral polarity within the Optic Vesicle, and loss of dorso-ventral polarity results in failure of Optic cup formation and domain specification, as shown by a reverse transplantation of the Optic Vesicle. We have shown previously that the ocular development depends not only on the signal within the antero-ventral Optic Vesicle but also on the extraocular signals. In the present study, using embryonic transplantation of a discrete portion of the embryonic chick brain, we demonstrate formation of a second eye from the antero-ventral hemicephalon when it was transplanted in the antero-dorsal hemicephalon of the host embryo. The transplant consists of an antero-ventral quadrant of the Optic Vesicle and the surrounding part of the anterior cephalon. The original dorso-ventral polarity of the transplant was once cancelled and re-established in accordance with that of the host embryo. Neither dorsal nor ventral cephalic halves in isolation did not develop into entire eye structures under the culture condition; the dorsal halves developed merely into the retinal pigmented epithelium and the ventral halves into the neural retina alone. The present study clearly suggests that extraocular dorsal and ventral signals counterbalance each other to specify the polarity of the Optic Vesicle.
Kunio Yasuda - One of the best experts on this subject based on the ideXlab platform.
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coordinated regulation of dorsal bone morphogenetic protein 4 and ventral sonic hedgehog signaling specifies the dorso ventral polarity in the Optic Vesicle and governs ocular morphogenesis through fibroblast growth factor 8 upregulation
Development Growth & Differentiation, 2010Co-Authors: Takuma Kobayashi, Kunio Yasuda, Masasuke ArakiAbstract:Dorsal and ventral specification in the early Optic Vesicle plays a crucial role in vertebrate ocular morphogenesis, and proper dorsal-ventral polarity in the Optic Vesicle ensures that distinct structures develop in separate domains within the eye primordium. The polarity is determined progressively during development by coordinated regulation of extraocular dorsal and ventral factors. In the present study, we cultured discrete portions of embryonic chick brains by preparing anterior cephalon, anterior dorsal cephalon and anterior ventral cephalon, and clearly demonstrate that bone morphogenetic protein 4 (BMP4) and Sonic hedgehog (Shh) constitute a dorsal-ventral signaling system together with fibroblast growth factor 8 (FGF8). BMP4 and Shh upregulate Tbx5 and Pax2, as reported previously, and at the same time Shh downregulates Tbx5, while BMP4 affects Pax2 expression to downregulate similarly. Shh induces Fgf8 expression in the ventral Optic Vesicle. This, in turn, determines the distinct boundary of the retinal pigmented epithelium and the neural retina by suppressing Mitf expression. The lens develops only when signals from both the dorsal and ventral regions come across together. Inverted deposition of Shh and BMP4 signals in organ-cultured Optic Vesicle completely re-organized ocular structures to be inverted. Based on these observations we propose a novel model in which the two signals govern the whole of ocular development when they encounter each other in the ocular morphogenic domain.
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Coordinated regulation of dorsal bone morphogenetic protein 4 and ventral Sonic hedgehog signaling specifies the dorso‐ventral polarity in the Optic Vesicle and governs ocular morphogenesis through fibroblast growth factor 8 upregulation
Development growth & differentiation, 2010Co-Authors: Takuma Kobayashi, Kunio Yasuda, Masasuke ArakiAbstract:Dorsal and ventral specification in the early Optic Vesicle plays a crucial role in vertebrate ocular morphogenesis, and proper dorsal-ventral polarity in the Optic Vesicle ensures that distinct structures develop in separate domains within the eye primordium. The polarity is determined progressively during development by coordinated regulation of extraocular dorsal and ventral factors. In the present study, we cultured discrete portions of embryonic chick brains by preparing anterior cephalon, anterior dorsal cephalon and anterior ventral cephalon, and clearly demonstrate that bone morphogenetic protein 4 (BMP4) and Sonic hedgehog (Shh) constitute a dorsal-ventral signaling system together with fibroblast growth factor 8 (FGF8). BMP4 and Shh upregulate Tbx5 and Pax2, as reported previously, and at the same time Shh downregulates Tbx5, while BMP4 affects Pax2 expression to downregulate similarly. Shh induces Fgf8 expression in the ventral Optic Vesicle. This, in turn, determines the distinct boundary of the retinal pigmented epithelium and the neural retina by suppressing Mitf expression. The lens develops only when signals from both the dorsal and ventral regions come across together. Inverted deposition of Shh and BMP4 signals in organ-cultured Optic Vesicle completely re-organized ocular structures to be inverted. Based on these observations we propose a novel model in which the two signals govern the whole of ocular development when they encounter each other in the ocular morphogenic domain.
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Generation of a second eye by embryonic transplantation of the antero‐ventral hemicephalon
Development growth & differentiation, 2009Co-Authors: Takuma Kobayashi, Kunio Yasuda, Masasuke ArakiAbstract:Vertebrate ocular morphogenesis requires proper dorso-ventral polarity within the Optic Vesicle, and loss of dorso-ventral polarity results in failure of Optic cup formation and domain specification, as shown by a reverse transplantation of the Optic Vesicle. We have shown previously that the ocular development depends not only on the signal within the antero-ventral Optic Vesicle but also on the extraocular signals. In the present study, using embryonic transplantation of a discrete portion of the embryonic chick brain, we demonstrate formation of a second eye from the antero-ventral hemicephalon when it was transplanted in the antero-dorsal hemicephalon of the host embryo. The transplant consists of an antero-ventral quadrant of the Optic Vesicle and the surrounding part of the anterior cephalon. The original dorso-ventral polarity of the transplant was once cancelled and re-established in accordance with that of the host embryo. Neither dorsal nor ventral cephalic halves in isolation did not develop into entire eye structures under the culture condition; the dorsal halves developed merely into the retinal pigmented epithelium and the ventral halves into the neural retina alone. The present study clearly suggests that extraocular dorsal and ventral signals counterbalance each other to specify the polarity of the Optic Vesicle.
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stage dependent expression of pax6 in Optic Vesicle cup regulates patterning genes through signaling molecules
Differentiation, 2007Co-Authors: Hasan Mahmud Reza, Yoshiko Takahashi, Kunio YasudaAbstract:Dorso-ventral and proximo-distal axis formation of the Optic cup is apparent from early stages of development. Pax6 is initially detectable in the Optic Vesicle and later shows a distal-high and proximal-low gradient of expression in the retina. To determine the early role of Pax6 in pattern formation of the Optic cup, we expressed Pax6 ectopically in the Optic Vesicle of stages 9–10 chick embryos by in ovo electroporation, which resulted in a small eye-like phenotype. The signaling molecule fibroblast growth factor (FGF)8, which appears to be restricted to the central retina, was increased, whereas bone morphogenetic protein (BMP)4 and Tbx5, two dorsal markers, were down-regulated in Pax6-electroporated eye. Pax6 overexpression also decreased the expression of the ventral marker Vax. Electroporation with a dominant-negative form of Pax6 resulted in a decrease in FGF8 expression, but BMP4 expression was unaffected initially while it was diminished later. Our data suggest a new role for Pax6 in regulating FGF8 and BMP4 expression during pattern formation of the Optic cup, and that a Pax6-regulated balance between FGF8 and BMP4 is critical for retinogenesis.
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Stage-dependent expression of Pax6 in Optic Vesicle/cup regulates patterning genes through signaling molecules.
Differentiation; research in biological diversity, 2007Co-Authors: Hasan Mahmud Reza, Yoshiko Takahashi, Kunio YasudaAbstract:Dorso-ventral and proximo-distal axis formation of the Optic cup is apparent from early stages of development. Pax6 is initially detectable in the Optic Vesicle and later shows a distal-high and proximal-low gradient of expression in the retina. To determine the early role of Pax6 in pattern formation of the Optic cup, we expressed Pax6 ectopically in the Optic Vesicle of stages 9–10 chick embryos by in ovo electroporation, which resulted in a small eye-like phenotype. The signaling molecule fibroblast growth factor (FGF)8, which appears to be restricted to the central retina, was increased, whereas bone morphogenetic protein (BMP)4 and Tbx5, two dorsal markers, were down-regulated in Pax6-electroporated eye. Pax6 overexpression also decreased the expression of the ventral marker Vax. Electroporation with a dominant-negative form of Pax6 resulted in a decrease in FGF8 expression, but BMP4 expression was unaffected initially while it was diminished later. Our data suggest a new role for Pax6 in regulating FGF8 and BMP4 expression during pattern formation of the Optic cup, and that a Pax6-regulated balance between FGF8 and BMP4 is critical for retinogenesis.
Takuma Kobayashi - One of the best experts on this subject based on the ideXlab platform.
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coordinated regulation of dorsal bone morphogenetic protein 4 and ventral sonic hedgehog signaling specifies the dorso ventral polarity in the Optic Vesicle and governs ocular morphogenesis through fibroblast growth factor 8 upregulation
Development Growth & Differentiation, 2010Co-Authors: Takuma Kobayashi, Kunio Yasuda, Masasuke ArakiAbstract:Dorsal and ventral specification in the early Optic Vesicle plays a crucial role in vertebrate ocular morphogenesis, and proper dorsal-ventral polarity in the Optic Vesicle ensures that distinct structures develop in separate domains within the eye primordium. The polarity is determined progressively during development by coordinated regulation of extraocular dorsal and ventral factors. In the present study, we cultured discrete portions of embryonic chick brains by preparing anterior cephalon, anterior dorsal cephalon and anterior ventral cephalon, and clearly demonstrate that bone morphogenetic protein 4 (BMP4) and Sonic hedgehog (Shh) constitute a dorsal-ventral signaling system together with fibroblast growth factor 8 (FGF8). BMP4 and Shh upregulate Tbx5 and Pax2, as reported previously, and at the same time Shh downregulates Tbx5, while BMP4 affects Pax2 expression to downregulate similarly. Shh induces Fgf8 expression in the ventral Optic Vesicle. This, in turn, determines the distinct boundary of the retinal pigmented epithelium and the neural retina by suppressing Mitf expression. The lens develops only when signals from both the dorsal and ventral regions come across together. Inverted deposition of Shh and BMP4 signals in organ-cultured Optic Vesicle completely re-organized ocular structures to be inverted. Based on these observations we propose a novel model in which the two signals govern the whole of ocular development when they encounter each other in the ocular morphogenic domain.
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Coordinated regulation of dorsal bone morphogenetic protein 4 and ventral Sonic hedgehog signaling specifies the dorso‐ventral polarity in the Optic Vesicle and governs ocular morphogenesis through fibroblast growth factor 8 upregulation
Development growth & differentiation, 2010Co-Authors: Takuma Kobayashi, Kunio Yasuda, Masasuke ArakiAbstract:Dorsal and ventral specification in the early Optic Vesicle plays a crucial role in vertebrate ocular morphogenesis, and proper dorsal-ventral polarity in the Optic Vesicle ensures that distinct structures develop in separate domains within the eye primordium. The polarity is determined progressively during development by coordinated regulation of extraocular dorsal and ventral factors. In the present study, we cultured discrete portions of embryonic chick brains by preparing anterior cephalon, anterior dorsal cephalon and anterior ventral cephalon, and clearly demonstrate that bone morphogenetic protein 4 (BMP4) and Sonic hedgehog (Shh) constitute a dorsal-ventral signaling system together with fibroblast growth factor 8 (FGF8). BMP4 and Shh upregulate Tbx5 and Pax2, as reported previously, and at the same time Shh downregulates Tbx5, while BMP4 affects Pax2 expression to downregulate similarly. Shh induces Fgf8 expression in the ventral Optic Vesicle. This, in turn, determines the distinct boundary of the retinal pigmented epithelium and the neural retina by suppressing Mitf expression. The lens develops only when signals from both the dorsal and ventral regions come across together. Inverted deposition of Shh and BMP4 signals in organ-cultured Optic Vesicle completely re-organized ocular structures to be inverted. Based on these observations we propose a novel model in which the two signals govern the whole of ocular development when they encounter each other in the ocular morphogenic domain.
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Generation of a second eye by embryonic transplantation of the antero‐ventral hemicephalon
Development growth & differentiation, 2009Co-Authors: Takuma Kobayashi, Kunio Yasuda, Masasuke ArakiAbstract:Vertebrate ocular morphogenesis requires proper dorso-ventral polarity within the Optic Vesicle, and loss of dorso-ventral polarity results in failure of Optic cup formation and domain specification, as shown by a reverse transplantation of the Optic Vesicle. We have shown previously that the ocular development depends not only on the signal within the antero-ventral Optic Vesicle but also on the extraocular signals. In the present study, using embryonic transplantation of a discrete portion of the embryonic chick brain, we demonstrate formation of a second eye from the antero-ventral hemicephalon when it was transplanted in the antero-dorsal hemicephalon of the host embryo. The transplant consists of an antero-ventral quadrant of the Optic Vesicle and the surrounding part of the anterior cephalon. The original dorso-ventral polarity of the transplant was once cancelled and re-established in accordance with that of the host embryo. Neither dorsal nor ventral cephalic halves in isolation did not develop into entire eye structures under the culture condition; the dorsal halves developed merely into the retinal pigmented epithelium and the ventral halves into the neural retina alone. The present study clearly suggests that extraocular dorsal and ventral signals counterbalance each other to specify the polarity of the Optic Vesicle.
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Anteroventrally localized activity in the Optic Vesicle plays a crucial role in the Optic development.
Developmental biology, 2008Co-Authors: Miki Hirashima, Takuma Kobayashi, Masanori Uchikawa, Hisato Kondoh, Masasuke ArakiAbstract:The vertebrate eye develops from the Optic Vesicle (OV), a laterally protrusive structure of the forebrain, by a coordinated interaction with surrounding tissues. The OV then invaginates to form an Optic cup, and the lens placode develops to the lens Vesicle at the same time. These aspects in the early stage characterize vertebrate eye formation and are controlled by appropriate dorsal-ventral coordination. In the present study, we performed surgical manipulation in the chick OV to remove either the dorsal or ventral half and examined the development of the remaining OV. The results show that the dorsal and ventral halves of the OV have a clearly different developmental pattern. When the dorsal half was removed, the remaining ventral OV developed into an entire eye, while the dorsal OV developed to a pigmented Vesicle consisting of retinal pigmented epithelium alone. These results indicate that the ventral part of the OV retains the potency to develop the entire eye structure and plays an essential role in proper eye development. In subsequent manipulations of early chick embryos, it was found that only the anterior ventral quadrant of the OV has the potential to develop the entire eye and that no other part of the OV has a similar activity. Fgf8 expression was localized in this portion and no Fgf8 expression was observed within the OV when the ventral OV was removed. These results suggest that the anterior ventral portion of the OV plays a crucial role in the proper development of the eye, possibly generating the dorsal-ventral gradients of signal proteins within the eye primordium.
Jason S Meyer - One of the best experts on this subject based on the ideXlab platform.
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generation of highly enriched populations of Optic Vesicle like retinal cells from human pluripotent stem cells
Current protocols in stem cell biology, 2015Co-Authors: Sarah K Ohlemacher, Clara Iglesias, Akshayalakshmi Sridhar, David M Gamm, Jason S MeyerAbstract:The protocol outlined below is used to differentiate human pluripotent stem cells (hPSCs) into retinal cell types through a process that faithfully recapitulates the stepwise progression observed in vivo. From pluripotency, cells are differentiated to a primitive anterior neural fate, followed by progression into two distinct populations of retinal progenitors and forebrain progenitors, each of which can be manually separated and purified. The hPSC-derived retinal progenitors are found to self-organize into three-dimensional Optic Vesicle-like structures, with each aggregate possessing the ability to differentiate into all major retinal cell types. The ability to faithfully recapitulate the stepwise in vivo development in a three-dimensional cell culture system allows for the study of mechanisms underlying human retinogenesis. Furthermore, this methodology allows for the study of retinal dysfunction and disease modeling using patient-derived cells, as well as high-throughput pharmacological screening and eventually patient-specific therapies.
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Current Protocols in Stem Cell Biology - Generation of highly enriched populations of Optic Vesicle-like retinal cells from human pluripotent stem cells
Current protocols in stem cell biology, 2015Co-Authors: Sarah K Ohlemacher, Clara Iglesias, Akshayalakshmi Sridhar, David M Gamm, Jason S MeyerAbstract:The protocol outlined below is used to differentiate human pluripotent stem cells (hPSCs) into retinal cell types through a process that faithfully recapitulates the stepwise progression observed in vivo. From pluripotency, cells are differentiated to a primitive anterior neural fate, followed by progression into two distinct populations of retinal progenitors and forebrain progenitors, each of which can be manually separated and purified. The hPSC-derived retinal progenitors are found to self-organize into three-dimensional Optic Vesicle-like structures, with each aggregate possessing the ability to differentiate into all major retinal cell types. The ability to faithfully recapitulate the stepwise in vivo development in a three-dimensional cell culture system allows for the study of mechanisms underlying human retinogenesis. Furthermore, this methodology allows for the study of retinal dysfunction and disease modeling using patient-derived cells, as well as high-throughput pharmacological screening and eventually patient-specific therapies.
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Loss of MITF expression during human embryonic stem cell differentiation disrupts retinal pigment epithelium development and Optic Vesicle cell proliferation
Human molecular genetics, 2014Co-Authors: Elizabeth E. Capowski, Lynda S. Wright, M. Joseph Phillips, Kyle Wallace, Anna Petelinsek, Isabel Pinilla, Sara E. Howden, Joseph M. Simonett, Eric M. Clark, Jason S MeyerAbstract:Microphthalmia-associated transcription factor (MITF) is a master regulator of pigmented cell survival and differentiation with direct transcriptional links to cell cycle, apoptosis and pigmentation. In mouse, Mitf is expressed early and uniformly in Optic Vesicle (OV) cells as they evaginate from the developing neural tube, and null Mitf mutations result in microphthalmia and pigmentation defects. However, homozygous mutations in MITF have not been identified in humans; therefore, little is known about its role in human retinogenesis. We used a human embryonic stem cell (hESC) model that recapitulates numerous aspects of retinal development, including OV specification and formation of retinal pigment epithelium (RPE) and neural retina progenitor cells (NRPCs), to investigate the earliest roles of MITF. During hESC differentiation toward a retinal lineage, a subset of MITF isoforms was expressed in a sequence and tissue distribution similar to that observed in mice. In addition, we found that promoters for the MITF-A, -D and -H isoforms were directly targeted by Visual Systems Homeobox 2 (VSX2), a transcription factor involved in patterning the OV toward a NRPC fate. We then manipulated MITF RNA and protein levels at early developmental stages and observed decreased expression of eye field transcription factors, reduced early OV cell proliferation and disrupted RPE maturation. This work provides a foundation for investigating MITF and other highly complex, multi-purposed transcription factors in a dynamic human developmental model system.
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Optic Vesicle like structures derived from human pluripotent stem cells facilitate a customized approach to retinal disease treatment
Stem Cells, 2011Co-Authors: Jason S Meyer, Elizabeth E. Capowski, Lynda S. Wright, Kyle Wallace, Sara E. Howden, Amelia D. Verhoeven, Jessica M. Martin, I Pinilla, Shulan TianAbstract:Differentiation methods for human induced pluripotent stem cells (hiPSCs) typically yield progeny from multiple tissue lineages, limiting their use for drug testing and autologous cell transplantation. In particular, early retina and forebrain derivatives often intermingle in pluripotent stem cell cultures, owing to their shared ancestry and tightly coupled development. Here, we demonstrate that three-dimensional populations of retinal progenitor cells (RPCs) can be isolated from early forebrain populations in both human embryonic stem cell and hiPSC cultures, providing a valuable tool for developmental, functional, and translational studies. Using our established protocol, we identified a transient population of Optic Vesicle (OV)-like structures that arose during a time period appropriate for normal human retinogenesis. These structures were independently cultured and analyzed to confirm their multipotent RPC status and capacity to produce physiologically responsive retinal cell types, including photoreceptors and retinal pigment epithelium (RPE). We then applied this method to hiPSCs derived from a patient with gyrate atrophy, a retinal degenerative disease affecting the RPE. RPE generated from these hiPSCs exhibited a disease-specific functional defect that could be corrected either by pharmacological means or following targeted gene repair. The production of OV-like populations from human pluripotent stem cells should facilitate the study of human retinal development and disease and advance the use of hiPSCs in personalized medicine.
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Optic Vesicle‐like Structures Derived from Human Pluripotent Stem Cells Facilitate a Customized Approach to Retinal Disease Treatment
Stem cells (Dayton Ohio), 2011Co-Authors: Jason S Meyer, Elizabeth E. Capowski, Lynda S. Wright, Kyle Wallace, Isabel Pinilla, Sara E. Howden, Amelia D. Verhoeven, Jessica M. Martin, Shulan Tian, Ron StewartAbstract:Differentiation methods for human induced pluripotent stem cells (hiPSCs) typically yield progeny from multiple tissue lineages, limiting their use for drug testing and autologous cell transplantation. In particular, early retina and forebrain derivatives often intermingle in pluripotent stem cell cultures, owing to their shared ancestry and tightly coupled development. Here, we demonstrate that three-dimensional populations of retinal progenitor cells (RPCs) can be isolated from early forebrain populations in both human embryonic stem cell and hiPSC cultures, providing a valuable tool for developmental, functional, and translational studies. Using our established protocol, we identified a transient population of Optic Vesicle (OV)-like structures that arose during a time period appropriate for normal human retinogenesis. These structures were independently cultured and analyzed to confirm their multipotent RPC status and capacity to produce physiologically responsive retinal cell types, including photoreceptors and retinal pigment epithelium (RPE). We then applied this method to hiPSCs derived from a patient with gyrate atrophy, a retinal degenerative disease affecting the RPE. RPE generated from these hiPSCs exhibited a disease-specific functional defect that could be corrected either by pharmacological means or following targeted gene repair. The production of OV-like populations from human pluripotent stem cells should facilitate the study of human retinal development and disease and advance the use of hiPSCs in personalized medicine.
Elizabeth E. Capowski - One of the best experts on this subject based on the ideXlab platform.
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Regulation of WNT Signaling by VSX2 During Optic Vesicle Patterning in Human Induced Pluripotent Stem Cells.
Stem cells (Dayton Ohio), 2016Co-Authors: Elizabeth E. Capowski, Lynda S. Wright, Kun Liang, M. Joseph Phillips, Kyle Wallace, Anna Petelinsek, Anna Hagstrom, Isabel Pinilla, Katarzyna D. Borys, Jessica LienAbstract:Few gene targets of Visual System Homeobox 2 (VSX2) have been identified despite its broad and critical role in the maintenance of neural retina (NR) fate during early retinogenesis. We performed VSX2 ChIP-seq and ChIP-PCR assays on early stage Optic Vesicle-like structures (OVs) derived from human iPS cells (hiPSCs), which highlighted WNT pathway genes as direct regulatory targets of VSX2. Examination of early NR patterning in hiPSC-OVs from a patient with a functional null mutation in VSX2 revealed mis-expression and upregulation of WNT pathway components and retinal pigmented epithelium (RPE) markers in comparison to control hiPSC-OVs. Furthermore, pharmacological inhibition of WNT signaling rescued the early mutant phenotype, whereas augmentation of WNT signaling in control hiPSC-OVs phenocopied the mutant. These findings reveal an important role for VSX2 as a regulator of WNT signaling and suggest that VSX2 may act to maintain NR identity at the expense of RPE in part by direct repression of WNT pathway constituents. Stem Cells 2016;34:2625-2634.
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Loss of MITF expression during human embryonic stem cell differentiation disrupts retinal pigment epithelium development and Optic Vesicle cell proliferation
Human molecular genetics, 2014Co-Authors: Elizabeth E. Capowski, Lynda S. Wright, M. Joseph Phillips, Kyle Wallace, Anna Petelinsek, Isabel Pinilla, Sara E. Howden, Joseph M. Simonett, Eric M. Clark, Jason S MeyerAbstract:Microphthalmia-associated transcription factor (MITF) is a master regulator of pigmented cell survival and differentiation with direct transcriptional links to cell cycle, apoptosis and pigmentation. In mouse, Mitf is expressed early and uniformly in Optic Vesicle (OV) cells as they evaginate from the developing neural tube, and null Mitf mutations result in microphthalmia and pigmentation defects. However, homozygous mutations in MITF have not been identified in humans; therefore, little is known about its role in human retinogenesis. We used a human embryonic stem cell (hESC) model that recapitulates numerous aspects of retinal development, including OV specification and formation of retinal pigment epithelium (RPE) and neural retina progenitor cells (NRPCs), to investigate the earliest roles of MITF. During hESC differentiation toward a retinal lineage, a subset of MITF isoforms was expressed in a sequence and tissue distribution similar to that observed in mice. In addition, we found that promoters for the MITF-A, -D and -H isoforms were directly targeted by Visual Systems Homeobox 2 (VSX2), a transcription factor involved in patterning the OV toward a NRPC fate. We then manipulated MITF RNA and protein levels at early developmental stages and observed decreased expression of eye field transcription factors, reduced early OV cell proliferation and disrupted RPE maturation. This work provides a foundation for investigating MITF and other highly complex, multi-purposed transcription factors in a dynamic human developmental model system.
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Blood-derived human iPS cells generate Optic Vesicle-like structures with the capacity to form retinal laminae and develop synapses.
Investigative ophthalmology & visual science, 2012Co-Authors: M. Joseph Phillips, Elizabeth E. Capowski, Lynda S. Wright, Kyle Wallace, Amelia D. Verhoeven, Jessica M. Martin, Sarah Jane Dickerson, Michael J. Miller, Wei Shen, E. Ferda PerçinAbstract:Purpose We sought to determine if human induced pluripotent stem cells (iPSCs) derived from blood could produce Optic Vesicle-like structures (OVs) with the capacity to stratify and express markers of intercellular communication. Methods Activated T-lymphocytes from a routine peripheral blood sample were reprogrammed by retroviral transduction to iPSCs. The T-lymphocyte-derived iPSCs (TiPSCs) were characterized for pluripotency and differentiated to OVs using our previously published protocol. TiPSC-OVs were then manually isolated, pooled, and cultured en masse to more mature stages of retinogenesis. Throughout this stepwise differentiation process, changes in anterior neural, retinal, and synaptic marker expression were monitored by PCR, immunocytochemistry, and/or flow cytometry. Results TiPSCs generated abundant OVs, which contained a near homogeneous population of proliferating neuroretinal progenitor cells (NRPCs). These NRPCs differentiated into multiple neuroretinal cell types, similar to OV cultures from human embryonic stem cells and fibroblast-derived iPSCs. In addition, portions of some TiPSC-OVs maintained their distinctive neuroepithelial appearance and spontaneously formed primitive laminae, reminiscent of the developing retina. Retinal progeny from TiPSC-OV cultures expressed numerous genes and proteins critical for synaptogenesis and gap junction formation, concomitant with the emergence of glia and the upregulation of thrombospondins in culture. Conclusions We demonstrate for the first time that human blood-derived iPSCs can generate retinal cell types, providing a highly convenient donor cell source for iPSC-based retinal studies. We also show that cultured TiPSC-OVs have the capacity to self-assemble into rudimentary neuroretinal structures and express markers indicative of chemical and electrical synapses.
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Optic Vesicle like structures derived from human pluripotent stem cells facilitate a customized approach to retinal disease treatment
Stem Cells, 2011Co-Authors: Jason S Meyer, Elizabeth E. Capowski, Lynda S. Wright, Kyle Wallace, Sara E. Howden, Amelia D. Verhoeven, Jessica M. Martin, I Pinilla, Shulan TianAbstract:Differentiation methods for human induced pluripotent stem cells (hiPSCs) typically yield progeny from multiple tissue lineages, limiting their use for drug testing and autologous cell transplantation. In particular, early retina and forebrain derivatives often intermingle in pluripotent stem cell cultures, owing to their shared ancestry and tightly coupled development. Here, we demonstrate that three-dimensional populations of retinal progenitor cells (RPCs) can be isolated from early forebrain populations in both human embryonic stem cell and hiPSC cultures, providing a valuable tool for developmental, functional, and translational studies. Using our established protocol, we identified a transient population of Optic Vesicle (OV)-like structures that arose during a time period appropriate for normal human retinogenesis. These structures were independently cultured and analyzed to confirm their multipotent RPC status and capacity to produce physiologically responsive retinal cell types, including photoreceptors and retinal pigment epithelium (RPE). We then applied this method to hiPSCs derived from a patient with gyrate atrophy, a retinal degenerative disease affecting the RPE. RPE generated from these hiPSCs exhibited a disease-specific functional defect that could be corrected either by pharmacological means or following targeted gene repair. The production of OV-like populations from human pluripotent stem cells should facilitate the study of human retinal development and disease and advance the use of hiPSCs in personalized medicine.
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Optic Vesicle‐like Structures Derived from Human Pluripotent Stem Cells Facilitate a Customized Approach to Retinal Disease Treatment
Stem cells (Dayton Ohio), 2011Co-Authors: Jason S Meyer, Elizabeth E. Capowski, Lynda S. Wright, Kyle Wallace, Isabel Pinilla, Sara E. Howden, Amelia D. Verhoeven, Jessica M. Martin, Shulan Tian, Ron StewartAbstract:Differentiation methods for human induced pluripotent stem cells (hiPSCs) typically yield progeny from multiple tissue lineages, limiting their use for drug testing and autologous cell transplantation. In particular, early retina and forebrain derivatives often intermingle in pluripotent stem cell cultures, owing to their shared ancestry and tightly coupled development. Here, we demonstrate that three-dimensional populations of retinal progenitor cells (RPCs) can be isolated from early forebrain populations in both human embryonic stem cell and hiPSC cultures, providing a valuable tool for developmental, functional, and translational studies. Using our established protocol, we identified a transient population of Optic Vesicle (OV)-like structures that arose during a time period appropriate for normal human retinogenesis. These structures were independently cultured and analyzed to confirm their multipotent RPC status and capacity to produce physiologically responsive retinal cell types, including photoreceptors and retinal pigment epithelium (RPE). We then applied this method to hiPSCs derived from a patient with gyrate atrophy, a retinal degenerative disease affecting the RPE. RPE generated from these hiPSCs exhibited a disease-specific functional defect that could be corrected either by pharmacological means or following targeted gene repair. The production of OV-like populations from human pluripotent stem cells should facilitate the study of human retinal development and disease and advance the use of hiPSCs in personalized medicine.