yaochen Li - Academia.edu (original) (raw)
Papers by yaochen Li
International Symposium on Access Spaces, 2011
This paper presents a novel method to compute vertex saliency from 3D facial meshes. Among the ma... more This paper presents a novel method to compute vertex saliency from 3D facial meshes. Among the many descriptors for vertices, Spin-image correlation and curvature are used based on competition and cooperation mechanisms. The proposed method has been tested on the IAIR-3Dface Database for evaluating the generated salient regions on 3D facial meshes. Experimental results demonstrate that both the abundance ratio and accuracy of the salient regions can be improved by the cooperation mechanisms compared to the competition mechanisms.
Image Processing, IEEE International Conference, 2011
Since Jacquin proposed original fractal image compression technique in 1990, fractal coding metho... more Since Jacquin proposed original fractal image compression technique in 1990, fractal coding method has been developed into various schemes. Traditionally, fractal coding uses mean square error (MSE) to evaluate similarity of image blocks, but the similarity evaluated by MSE usually differs from human visual system (HVS). Compared with MSE, structural similarity (SSIM) is an image measure index which is more
International Conference on Multimedia Computing and Systems/International Conference on Multimedia and Expo, 2011
This paper proposes a 3D facial mesh detection algorithm based on the geometric saliency of surfa... more This paper proposes a 3D facial mesh detection algorithm based on the geometric saliency of surface. Specifically, the geometric saliency of each vertex on 3D triangle mesh is measured by the combination of Gaussian-weighted curvature and spin-image correlation. Salient vertices with similar properties are clustered into regions on the saliency map, and represented as nodes by the graph model. To
17th International IEEE Conference on Intelligent Transportation Systems (ITSC), 2014
2011 IEEE International Conference on Multimedia and Expo, 2011
This paper proposes a 3D facial mesh detection algorithm based on the geometric saliency of surfa... more This paper proposes a 3D facial mesh detection algorithm based on the geometric saliency of surface. Specifically, the geometric saliency of each vertex on 3D triangle mesh is measured by the combination of Gaussian-weighted curvature and spin-image correlation. Salient vertices with similar properties are clustered into regions on the saliency map, and represented as nodes by the graph model. To
2011 1st International Symposium on Access Spaces (ISAS), 2011
This paper presents a novel method to compute vertex saliency from 3D facial meshes. Among the ma... more This paper presents a novel method to compute vertex saliency from 3D facial meshes. Among the many descriptors for vertices, Spin-image correlation and curvature are used based on competition and cooperation mechanisms. The proposed method has been tested on the IAIR-3Dface Database for evaluating the generated salient regions on 3D facial meshes. Experimental results demonstrate that both the abundance ratio
2011 18th IEEE International Conference on Image Processing, 2011
Since Jacquin proposed original fractal image compression technique in 1990, fractal coding metho... more Since Jacquin proposed original fractal image compression technique in 1990, fractal coding method has been developed into various schemes. Traditionally, fractal coding uses mean square error (MSE) to evaluate similarity of image blocks, but the similarity evaluated by MSE usually differs from human visual system (HVS). Compared with MSE, structural similarity (SSIM) is an image measure index which is more
Cancer Biology & Therapy, 2007
ABSTRACT Understanding the biology of breast cancer stem cells and trying new ways to obliterate ... more ABSTRACT Understanding the biology of breast cancer stem cells and trying new ways to obliterate these cells would be a key step in developing cures for breast cancer. The objective of this study was to investigate the effect of mutant TNF-α on human breast cancer stem cells derived from MCF7 cell line under the characterization of biologic features of these cells in vitro. By FACS analysis and sorting, we got MCF7 side population (SP) cells and showed that MCF7 SP cells possess cancer stem cell characteristics using the accepted breast cancer stem cell markers, but do not express multiple drug resistance transporters. Furthermore, by RT-PCR, these stem cells were found to constitutively express TNFR-p55 and TNFR-p75. After being treated with Mt rh471 TNF-a, SP cells displayed a decreased self-renewal ability and an increased apoptosis by three different methods. When monocolony antibody against TNFR-p55 was added into the culture medium, the inhibitory effect of Mt rh471 TNF-α on self-renewal was blocked completely, but this was not the case for that of Wt rhTNF-α. The possible reasons might be that the increased binding of Mt rh471 TNF-α mainly to TNFR-p55 results in induction of apoptosis of SP cells, while Wt rhTNF-α could bind to both TNFR-p55 and TNFR-p75 which would lead to NF-κB activity, resulting in a discounted apoptotic effect. These data suggest that Mt rh471 TNF-a might be a negative regulator of the breast cancer stem cell-like cells and have the potential to treat breast cancer in clinic.
Biochemistry and Cell Biology, 2007
The search for an effective immunotherapeutic treatment for tumors is an important area of cancer... more The search for an effective immunotherapeutic treatment for tumors is an important area of cancer research. To prepare a more effective form of the bifunctional fusion protein IL2-B7.1(IgV+C) and analyze its effect on the stimulation of T lymphocyte proliferation, we used DNAStar 5.03 software to predict the structural diversity and biochemical character of IL2-B7.1(IgV+C). We then prepared fusion protein IL2-B7.1(IgV+C) by establishing its prokaryotic expression system, and tested its effect on the stimulation of T lymphocytes in vitro. The results indicated that IL2-B7.1(IgV+C) correctly formed a secondary structure in which both IL2 and B7.1(IgV+C) maintained their original hydrophilicity and epitopes. Western blot analysis revealed that IL2-B7.1(IgV+C) was efficiently expressed. Our analysis of CTLL-2 and T-cell proliferation showed that recombinant human (rh) IL2-B7.1(IgV+C) exerted the combined stimulating effects of both rhIL2 and rh B7.1(IgV+C) on cell proliferation, and that these effects could be blocked by adding either anti-IL2 or anti-B7.1 monoclonal antibodies. A >2-fold increase in [3H]TdR incorporation compared with that of cells treated with recombinant protein IL2, or B7.1(IgV+C) alone, revealed that rhIL2-B7.1(IgV+C) had dose-dependent synergetic effects on T-cell activation in the presence of anti-CD3 monoclonal antibody. We concluded that the augmented potency of rhIL2-B7.1(IgV+C) resulted in a stronger stimulation of T-cell proliferation than either rhB7.1(IgV+C) or rhIL2 alone.
Experimental Eye Research, 2015
Müller cells can completely repair retinal injury by acting as endogenous stem/progenitor cells i... more Müller cells can completely repair retinal injury by acting as endogenous stem/progenitor cells in lower-order vertebrates. However, a safe and effective approach to activate progenitor potential of retinal Müller cells in higher-order vertebrates, which rarely re-enter the cell cycle, is a bottleneck problem. In the present study, Royal College of Surgeon's (RCS) rats were subjected to rat bone marrow mesenchymal stem cells (rBMSCs) subretinal space transplantation. Electroretinography (ERG) recordings showed that the b-wave amplitudes and ONL thicknesses statistically increased after transplantation. The number of Müller cells expressing proliferative, stem/progenitor and neuronal markers significantly increased after rBMSCs transplantation in vivo or after co-culturing with rBMSCs in vitro. The cultured rBMSCs could secrete nerve growth factor (NGF). In addition, we confirmed that NGF or NGF-neutralizing antibody could activate or depress Müller cells dedifferentiation, both in vivo and in vitro. Furthermore, Müller cells expressing high levels of the NGF receptor neurotrophic tyrosine kinase receptor type 1 (TrkA) were observed in the retinas of rats transplanted with rBMSCs. Moreover, the protein expression of downstream elements of NGF/TrkA signaling, such as p-PI3K, p-Akt and p-CREB, increased in Müller cells in the retinas of rBMSCs-treated rats in vivo or in Müller cells co-cultured with rBMSCs in vitro. Blocking TrkA with K-252a reduced the number of dedifferentiated Müller cells and the expression of NGF/TrkA signaling in vitro. Thus, rBMSCs might initiate endogenous regenerative mechanisms, which may constitute a new therapeutic strategy for retinal dystrophic diseases.
STEM CELLS, 2012
a These authors contributed equally to this work; b The Jackson Laboratory, Bar Harbor, Maine, US... more a These authors contributed equally to this work; b The Jackson Laboratory, Bar Harbor, Maine, USA ABSTRACT The Notch pathway plays a pivotal role in regulating cell fate decisions in many stem cell systems. However, the full repertoire of Notch target genes in vivo and the mechanisms through which this pathway activity is integrated with other signaling pathways are largely unknown. Here, we report a transgenic mouse in which the activation of the Notch pathway massively expands the neural stem cell (NSC) pool in a cell context-dependent manner. Using this in vivo system, we identify direct targets of RBPJ/N1ICD in cortical NSCs at a genome-wide level through combined ChIP-Seq and transcriptome analyses. Through a highly conservative analysis of these datasets, we identified 98 genes that are directly regulated by N1ICD/RPBJ in vivo. These include many transcription factors that are known to be critical for NSC self-renewal (Sox2, Pax6, Tlx, and Id4) and the transcriptional effectors of the Wnt, SHH, and Hippo pathways, TCF4, Gli2, Gli3, Yap1, and Tead2.
a These authors contributed equally to this work; b The Jackson Laboratory, Bar Harbor, Maine, US... more a These authors contributed equally to this work; b The Jackson Laboratory, Bar Harbor, Maine, USA ABSTRACT The Notch pathway plays a pivotal role in regulating cell fate decisions in many stem cell systems. However, the full repertoire of Notch target genes in vivo and the mechanisms through which this pathway activity is integrated with other signaling pathways are largely unknown. Here, we report a transgenic mouse in which the activation of the Notch pathway massively expands the neural stem cell (NSC) pool in a cell context-dependent manner. Using this in vivo system, we identify direct targets of RBPJ/N1ICD in cortical NSCs at a genome-wide level through combined ChIP-Seq and transcriptome analyses. Through a highly conservative analysis of these datasets, we identified 98 genes that are directly regulated by N1ICD/RPBJ in vivo. These include many transcription factors that are known to be critical for NSC self-renewal (Sox2, Pax6, Tlx, and Id4) and the transcriptional effectors of the Wnt, SHH, and Hippo pathways, TCF4, Gli2, Gli3, Yap1, and Tead2.
Cellular Signalling, 2000
The photopigment melanopsin and melanopsin-containing RGCs (mRGCs or ipRGCs) represent a brand-ne... more The photopigment melanopsin and melanopsin-containing RGCs (mRGCs or ipRGCs) represent a brand-new and exciting direction in the field of visual field. Although the melanopsin is much less sensitive to light and has far less spatial resolution, mRGCs have the unique ability to project to brain areas by the retinohypothalamic tract (RHT) and communicate directly with the brain. Unfortunately, melanopsin presents lower expression levels in many acute and chronic retinal diseases. The molecular mechanisms underlying melanopsin expression are not yet really understood. MicroRNAs play important roles in the control of development. Most importantly, the link of microRNA biology to a diverse set of cellular processes, ranging from proliferation, apoptosis and malignant transformation to neuronal development and fate specification is emerging. We employed Royal College of Surgeon (RCS) rats as animal model to investigate the underlying molecular mechanism regulating melanopsin expression using a panel of miRNA by quantitative real-time reverse transcription polymerase chain reaction. We identified a microRNA, mir133b, that is specifically expressed in retinal dopaminergic amacrine cells as well as markedly increased expression at early stage during retinal degeneration in RCS rats. The overexpression of mir133b downregulates the important transcription factor Pitx3 expression in dopaminergic amacrine cells in RCS rats retinas and makes amacrine cells stratification deficit in IPL. Furthermore, deficient dopaminergic amacrine cells presented decreased TH expression and dopamine production, which lead to a failure to direct mRGCs dendrite to stratify and enter INL and lead to the reduced correct connections between amacrine cells and mRGCs. Our study suggested that overexpression of mir133b and downregulated Pitx3 suppress maturation and function of dopaminergic amacrine cells, and overexpression of mir133b decreased TH and D2 receptor expression as well as dopamine production, which finally resulted in reduced melanopsin expression.► The melanopsin expression is decreased in RCS rats. ► The numbers of mRGCs don’t change. ► Disrupted DA ACs cause a great affection to melanopsin expression. ► The overexpressed mir133b may involve in collapse of DA ACs. ► Interfered mir-133b restores DA ACs’ functions and melanopsin expression level.
Molecular Neurobiology, 2013
Sodium iodate (NaIO 3 )-induced retina injury is one of models that is commonly used to study var... more Sodium iodate (NaIO 3 )-induced retina injury is one of models that is commonly used to study various retinal diseases caused by retinal pigment epithelium (RPE) injury such as AMD. Previous researches have revealed that RPE and photoreceptors are main impaired objects in this model. By comparison, intra-retinal layer has not been studied in detail after NaIO 3 administration. In this study, we present evidences that intra-retinal neurons can be directly injured by NaIO 3 at early stage and that the morphology had taken obvious changes, the decreased areas of dendritic fields of dopaminergic amacrine cells (DA-ACs), horizontal cells, and melanopsin-expressing retinal ganglion cells (mRGCs). Moreover, we found that miRNA 133b that was considered specifically to express in midbrain dopaminergic neurons was markedly upregulated in retinal DA-ACs after NaIO 3 administration. The overexpression of mir-133b negatively regulated the expression of pitx3, an important transcription factor, and led to a series of deficits of DA-ACs such as TH and D2 receptor expression and DA producing, which may play a causative role in pathological events of horizontal cells and mRGCs. After mir-133b was
Cellular Signalling, 2012
Keywords: MicroRNA mir133b Pitx3 mRGCs Melanopsin Dopaminergic amacrine cells TH D2 receptor
![Research paper thumbnail of Corrigendum to “The changes of potassium currents in RCS rat Müller cell during retinal degeneration” [Brain Res. 1427 (2011) 78–87]](https://attachments.academia-assets.com/47250633/thumbnails/1.jpg)
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Brain Research, 2012
Müller cells are the principal glial cells expressing membrane-bound potassium channel and predom... more Müller cells are the principal glial cells expressing membrane-bound potassium channel and predominantly mediating the homeostatic regulation of extracellular K + produced by neuronal activity in retina. It's well known that Müller cells can be activated in many pathological conditions, but little is known about the change of potassium currents of Müller cells during the progression of retinitis pigmentosa. Herein, the Royal College of Surgeons rats (RCS rat) were employed to investigate some phenotypic and functional changes of Müller cells during retinal degeneration such as the expression of Kir4.1, membrane properties and K + channel currents by using immunohistochemistry, RT-PCR, western blot and whole-cell patch clamping respectively. Compared with Müller cells in control retina, increased glutamine synthetase (GS) mRNA levels were seen at P30 and P60, and then decreased gradually in RCS rat retina. Morphologically, Müller cells showed significant hypertrophy and proliferation after p60. The increased expression of intermediate filament, glial fibrillary acidic protein (GFAP)
International Symposium on Access Spaces, 2011
This paper presents a novel method to compute vertex saliency from 3D facial meshes. Among the ma... more This paper presents a novel method to compute vertex saliency from 3D facial meshes. Among the many descriptors for vertices, Spin-image correlation and curvature are used based on competition and cooperation mechanisms. The proposed method has been tested on the IAIR-3Dface Database for evaluating the generated salient regions on 3D facial meshes. Experimental results demonstrate that both the abundance ratio and accuracy of the salient regions can be improved by the cooperation mechanisms compared to the competition mechanisms.
Image Processing, IEEE International Conference, 2011
Since Jacquin proposed original fractal image compression technique in 1990, fractal coding metho... more Since Jacquin proposed original fractal image compression technique in 1990, fractal coding method has been developed into various schemes. Traditionally, fractal coding uses mean square error (MSE) to evaluate similarity of image blocks, but the similarity evaluated by MSE usually differs from human visual system (HVS). Compared with MSE, structural similarity (SSIM) is an image measure index which is more
International Conference on Multimedia Computing and Systems/International Conference on Multimedia and Expo, 2011
This paper proposes a 3D facial mesh detection algorithm based on the geometric saliency of surfa... more This paper proposes a 3D facial mesh detection algorithm based on the geometric saliency of surface. Specifically, the geometric saliency of each vertex on 3D triangle mesh is measured by the combination of Gaussian-weighted curvature and spin-image correlation. Salient vertices with similar properties are clustered into regions on the saliency map, and represented as nodes by the graph model. To
17th International IEEE Conference on Intelligent Transportation Systems (ITSC), 2014
2011 IEEE International Conference on Multimedia and Expo, 2011
This paper proposes a 3D facial mesh detection algorithm based on the geometric saliency of surfa... more This paper proposes a 3D facial mesh detection algorithm based on the geometric saliency of surface. Specifically, the geometric saliency of each vertex on 3D triangle mesh is measured by the combination of Gaussian-weighted curvature and spin-image correlation. Salient vertices with similar properties are clustered into regions on the saliency map, and represented as nodes by the graph model. To
2011 1st International Symposium on Access Spaces (ISAS), 2011
This paper presents a novel method to compute vertex saliency from 3D facial meshes. Among the ma... more This paper presents a novel method to compute vertex saliency from 3D facial meshes. Among the many descriptors for vertices, Spin-image correlation and curvature are used based on competition and cooperation mechanisms. The proposed method has been tested on the IAIR-3Dface Database for evaluating the generated salient regions on 3D facial meshes. Experimental results demonstrate that both the abundance ratio
2011 18th IEEE International Conference on Image Processing, 2011
Since Jacquin proposed original fractal image compression technique in 1990, fractal coding metho... more Since Jacquin proposed original fractal image compression technique in 1990, fractal coding method has been developed into various schemes. Traditionally, fractal coding uses mean square error (MSE) to evaluate similarity of image blocks, but the similarity evaluated by MSE usually differs from human visual system (HVS). Compared with MSE, structural similarity (SSIM) is an image measure index which is more
Cancer Biology & Therapy, 2007
ABSTRACT Understanding the biology of breast cancer stem cells and trying new ways to obliterate ... more ABSTRACT Understanding the biology of breast cancer stem cells and trying new ways to obliterate these cells would be a key step in developing cures for breast cancer. The objective of this study was to investigate the effect of mutant TNF-α on human breast cancer stem cells derived from MCF7 cell line under the characterization of biologic features of these cells in vitro. By FACS analysis and sorting, we got MCF7 side population (SP) cells and showed that MCF7 SP cells possess cancer stem cell characteristics using the accepted breast cancer stem cell markers, but do not express multiple drug resistance transporters. Furthermore, by RT-PCR, these stem cells were found to constitutively express TNFR-p55 and TNFR-p75. After being treated with Mt rh471 TNF-a, SP cells displayed a decreased self-renewal ability and an increased apoptosis by three different methods. When monocolony antibody against TNFR-p55 was added into the culture medium, the inhibitory effect of Mt rh471 TNF-α on self-renewal was blocked completely, but this was not the case for that of Wt rhTNF-α. The possible reasons might be that the increased binding of Mt rh471 TNF-α mainly to TNFR-p55 results in induction of apoptosis of SP cells, while Wt rhTNF-α could bind to both TNFR-p55 and TNFR-p75 which would lead to NF-κB activity, resulting in a discounted apoptotic effect. These data suggest that Mt rh471 TNF-a might be a negative regulator of the breast cancer stem cell-like cells and have the potential to treat breast cancer in clinic.
Biochemistry and Cell Biology, 2007
The search for an effective immunotherapeutic treatment for tumors is an important area of cancer... more The search for an effective immunotherapeutic treatment for tumors is an important area of cancer research. To prepare a more effective form of the bifunctional fusion protein IL2-B7.1(IgV+C) and analyze its effect on the stimulation of T lymphocyte proliferation, we used DNAStar 5.03 software to predict the structural diversity and biochemical character of IL2-B7.1(IgV+C). We then prepared fusion protein IL2-B7.1(IgV+C) by establishing its prokaryotic expression system, and tested its effect on the stimulation of T lymphocytes in vitro. The results indicated that IL2-B7.1(IgV+C) correctly formed a secondary structure in which both IL2 and B7.1(IgV+C) maintained their original hydrophilicity and epitopes. Western blot analysis revealed that IL2-B7.1(IgV+C) was efficiently expressed. Our analysis of CTLL-2 and T-cell proliferation showed that recombinant human (rh) IL2-B7.1(IgV+C) exerted the combined stimulating effects of both rhIL2 and rh B7.1(IgV+C) on cell proliferation, and that these effects could be blocked by adding either anti-IL2 or anti-B7.1 monoclonal antibodies. A >2-fold increase in [3H]TdR incorporation compared with that of cells treated with recombinant protein IL2, or B7.1(IgV+C) alone, revealed that rhIL2-B7.1(IgV+C) had dose-dependent synergetic effects on T-cell activation in the presence of anti-CD3 monoclonal antibody. We concluded that the augmented potency of rhIL2-B7.1(IgV+C) resulted in a stronger stimulation of T-cell proliferation than either rhB7.1(IgV+C) or rhIL2 alone.
Experimental Eye Research, 2015
Müller cells can completely repair retinal injury by acting as endogenous stem/progenitor cells i... more Müller cells can completely repair retinal injury by acting as endogenous stem/progenitor cells in lower-order vertebrates. However, a safe and effective approach to activate progenitor potential of retinal Müller cells in higher-order vertebrates, which rarely re-enter the cell cycle, is a bottleneck problem. In the present study, Royal College of Surgeon's (RCS) rats were subjected to rat bone marrow mesenchymal stem cells (rBMSCs) subretinal space transplantation. Electroretinography (ERG) recordings showed that the b-wave amplitudes and ONL thicknesses statistically increased after transplantation. The number of Müller cells expressing proliferative, stem/progenitor and neuronal markers significantly increased after rBMSCs transplantation in vivo or after co-culturing with rBMSCs in vitro. The cultured rBMSCs could secrete nerve growth factor (NGF). In addition, we confirmed that NGF or NGF-neutralizing antibody could activate or depress Müller cells dedifferentiation, both in vivo and in vitro. Furthermore, Müller cells expressing high levels of the NGF receptor neurotrophic tyrosine kinase receptor type 1 (TrkA) were observed in the retinas of rats transplanted with rBMSCs. Moreover, the protein expression of downstream elements of NGF/TrkA signaling, such as p-PI3K, p-Akt and p-CREB, increased in Müller cells in the retinas of rBMSCs-treated rats in vivo or in Müller cells co-cultured with rBMSCs in vitro. Blocking TrkA with K-252a reduced the number of dedifferentiated Müller cells and the expression of NGF/TrkA signaling in vitro. Thus, rBMSCs might initiate endogenous regenerative mechanisms, which may constitute a new therapeutic strategy for retinal dystrophic diseases.
STEM CELLS, 2012
a These authors contributed equally to this work; b The Jackson Laboratory, Bar Harbor, Maine, US... more a These authors contributed equally to this work; b The Jackson Laboratory, Bar Harbor, Maine, USA ABSTRACT The Notch pathway plays a pivotal role in regulating cell fate decisions in many stem cell systems. However, the full repertoire of Notch target genes in vivo and the mechanisms through which this pathway activity is integrated with other signaling pathways are largely unknown. Here, we report a transgenic mouse in which the activation of the Notch pathway massively expands the neural stem cell (NSC) pool in a cell context-dependent manner. Using this in vivo system, we identify direct targets of RBPJ/N1ICD in cortical NSCs at a genome-wide level through combined ChIP-Seq and transcriptome analyses. Through a highly conservative analysis of these datasets, we identified 98 genes that are directly regulated by N1ICD/RPBJ in vivo. These include many transcription factors that are known to be critical for NSC self-renewal (Sox2, Pax6, Tlx, and Id4) and the transcriptional effectors of the Wnt, SHH, and Hippo pathways, TCF4, Gli2, Gli3, Yap1, and Tead2.
a These authors contributed equally to this work; b The Jackson Laboratory, Bar Harbor, Maine, US... more a These authors contributed equally to this work; b The Jackson Laboratory, Bar Harbor, Maine, USA ABSTRACT The Notch pathway plays a pivotal role in regulating cell fate decisions in many stem cell systems. However, the full repertoire of Notch target genes in vivo and the mechanisms through which this pathway activity is integrated with other signaling pathways are largely unknown. Here, we report a transgenic mouse in which the activation of the Notch pathway massively expands the neural stem cell (NSC) pool in a cell context-dependent manner. Using this in vivo system, we identify direct targets of RBPJ/N1ICD in cortical NSCs at a genome-wide level through combined ChIP-Seq and transcriptome analyses. Through a highly conservative analysis of these datasets, we identified 98 genes that are directly regulated by N1ICD/RPBJ in vivo. These include many transcription factors that are known to be critical for NSC self-renewal (Sox2, Pax6, Tlx, and Id4) and the transcriptional effectors of the Wnt, SHH, and Hippo pathways, TCF4, Gli2, Gli3, Yap1, and Tead2.
Cellular Signalling, 2000
The photopigment melanopsin and melanopsin-containing RGCs (mRGCs or ipRGCs) represent a brand-ne... more The photopigment melanopsin and melanopsin-containing RGCs (mRGCs or ipRGCs) represent a brand-new and exciting direction in the field of visual field. Although the melanopsin is much less sensitive to light and has far less spatial resolution, mRGCs have the unique ability to project to brain areas by the retinohypothalamic tract (RHT) and communicate directly with the brain. Unfortunately, melanopsin presents lower expression levels in many acute and chronic retinal diseases. The molecular mechanisms underlying melanopsin expression are not yet really understood. MicroRNAs play important roles in the control of development. Most importantly, the link of microRNA biology to a diverse set of cellular processes, ranging from proliferation, apoptosis and malignant transformation to neuronal development and fate specification is emerging. We employed Royal College of Surgeon (RCS) rats as animal model to investigate the underlying molecular mechanism regulating melanopsin expression using a panel of miRNA by quantitative real-time reverse transcription polymerase chain reaction. We identified a microRNA, mir133b, that is specifically expressed in retinal dopaminergic amacrine cells as well as markedly increased expression at early stage during retinal degeneration in RCS rats. The overexpression of mir133b downregulates the important transcription factor Pitx3 expression in dopaminergic amacrine cells in RCS rats retinas and makes amacrine cells stratification deficit in IPL. Furthermore, deficient dopaminergic amacrine cells presented decreased TH expression and dopamine production, which lead to a failure to direct mRGCs dendrite to stratify and enter INL and lead to the reduced correct connections between amacrine cells and mRGCs. Our study suggested that overexpression of mir133b and downregulated Pitx3 suppress maturation and function of dopaminergic amacrine cells, and overexpression of mir133b decreased TH and D2 receptor expression as well as dopamine production, which finally resulted in reduced melanopsin expression.► The melanopsin expression is decreased in RCS rats. ► The numbers of mRGCs don’t change. ► Disrupted DA ACs cause a great affection to melanopsin expression. ► The overexpressed mir133b may involve in collapse of DA ACs. ► Interfered mir-133b restores DA ACs’ functions and melanopsin expression level.
Molecular Neurobiology, 2013
Sodium iodate (NaIO 3 )-induced retina injury is one of models that is commonly used to study var... more Sodium iodate (NaIO 3 )-induced retina injury is one of models that is commonly used to study various retinal diseases caused by retinal pigment epithelium (RPE) injury such as AMD. Previous researches have revealed that RPE and photoreceptors are main impaired objects in this model. By comparison, intra-retinal layer has not been studied in detail after NaIO 3 administration. In this study, we present evidences that intra-retinal neurons can be directly injured by NaIO 3 at early stage and that the morphology had taken obvious changes, the decreased areas of dendritic fields of dopaminergic amacrine cells (DA-ACs), horizontal cells, and melanopsin-expressing retinal ganglion cells (mRGCs). Moreover, we found that miRNA 133b that was considered specifically to express in midbrain dopaminergic neurons was markedly upregulated in retinal DA-ACs after NaIO 3 administration. The overexpression of mir-133b negatively regulated the expression of pitx3, an important transcription factor, and led to a series of deficits of DA-ACs such as TH and D2 receptor expression and DA producing, which may play a causative role in pathological events of horizontal cells and mRGCs. After mir-133b was
Cellular Signalling, 2012
Keywords: MicroRNA mir133b Pitx3 mRGCs Melanopsin Dopaminergic amacrine cells TH D2 receptor
Brain Research, 2012
Müller cells are the principal glial cells expressing membrane-bound potassium channel and predom... more Müller cells are the principal glial cells expressing membrane-bound potassium channel and predominantly mediating the homeostatic regulation of extracellular K + produced by neuronal activity in retina. It's well known that Müller cells can be activated in many pathological conditions, but little is known about the change of potassium currents of Müller cells during the progression of retinitis pigmentosa. Herein, the Royal College of Surgeons rats (RCS rat) were employed to investigate some phenotypic and functional changes of Müller cells during retinal degeneration such as the expression of Kir4.1, membrane properties and K + channel currents by using immunohistochemistry, RT-PCR, western blot and whole-cell patch clamping respectively. Compared with Müller cells in control retina, increased glutamine synthetase (GS) mRNA levels were seen at P30 and P60, and then decreased gradually in RCS rat retina. Morphologically, Müller cells showed significant hypertrophy and proliferation after p60. The increased expression of intermediate filament, glial fibrillary acidic protein (GFAP)