Publications by authors named "Xueting Luo"

40 Publications

Modeling Cone/Cone-Rod Dystrophy Pathology by AAV-Mediated Overexpression of Mutant CRX Protein in the Mouse Retina.

Transl Vis Sci Technol 2021 06;10(7):25

Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.

Purpose: This study aims to evaluate the pathogenesis of cone/cone-rod dystrophy (CoD/CoRD) caused by a cone-rod homeobox (CRX) mutation, which was identified in a Chinese family, through adeno-associated virus (AAV)-mediated overexpression of mutant CRX protein in the mouse retina.

Methods: Comprehensive ophthalmologic examinations were performed for the pedigree members of a Chinese family with CoD/CoRD. Whole exome sequencing and Sanger sequencing were performed to determine the genetic cause of the disease. Furthermore, AAV vectors were used to construct AAV-CRX-mut-HA, which was transfected into mouse photoreceptor cells to clarify the pathogenesis of the mutant CRX.

Results: Fundus photography and optical coherence tomography images displayed features that were consistent with CoD/CoRD, including macular atrophy and photoreceptor layer thinning. Electroretinogram analysis indicated an obvious decrease in photopic responses or both scotopic and photopic responses in affected individuals. A frameshift variant c.611delC (p.S204fs) in CRX was cosegregated with the disease in this family. AAV-CRX-mut-HA that subretinally injected into the C57BL/6 mice generally transfected the outer nuclear layer, leading to the loss of cone and rod photoreceptor cells, abnormal expression of CRX target genes, and a decrease in electroretinogram responses.

Conclusions: AAV-mediated overexpression of CRX[S204fs] in the mouse retina led to a CoRD-like phenotype and showed the possible pathogenesis of the antimorphic CRX mutation.

Translational Relevance: This study provides a modeling method to evaluate the pathogenesis of CoD/CoRD and other inherited retinal dystrophies caused by distinct gain-of-function mutations.
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http://dx.doi.org/10.1167/tvst.10.7.25DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8237110PMC
June 2021

The Interaction Between Microglia and Macroglia in Glaucoma.

Front Neurosci 2021 28;15:610788. Epub 2021 May 28.

Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai General Hospital, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China.

Glaucoma, a neurodegenerative disease that leads to irreversible vision loss, is characterized by progressive loss of retinal ganglion cells (RGCs) and optic axons. To date, elevated intraocular pressure (IOP) has been recognized as the main phenotypic factor associated with glaucoma. However, some patients with normal IOP also have glaucomatous visual impairment and RGC loss. Unfortunately, the underlying mechanisms behind such cases remain unclear. Recent studies have suggested that retinal glia play significant roles in the initiation and progression of glaucoma. Multiple types of glial cells are activated in glaucoma. Microglia, for example, act as critical mediators that orchestrate the progression of neuroinflammation through pro-inflammatory cytokines. In contrast, macroglia (astrocytes and Müller cells) participate in retinal inflammatory responses as modulators and contribute to neuroprotection through the secretion of neurotrophic factors. Notably, research results have indicated that intricate interactions between microglia and macroglia might provide potential therapeutic targets for the prevention and treatment of glaucoma. In this review, we examine the specific roles of microglia and macroglia in open-angle glaucoma, including glaucoma in animal models, and analyze the interaction between these two cell types. In addition, we discuss potential treatment options based on the relationship between glial cells and neurons.
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http://dx.doi.org/10.3389/fnins.2021.610788DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8193936PMC
May 2021

Clinical outcomes of open treatment of old condylar head fractures in adults.

J Craniomaxillofac Surg 2021 Jun 28;49(6):480-487. Epub 2021 Feb 28.

State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthognathic and TMJ Surgery, West China Hospital of Stomatology, Sichuan University, No. 14, 3rd Section of Ren Min Nan Lu Road, Chengdu, China. Electronic address:

The aim of this study was to classify the clinical feasibility and outcomes of open reduction treatment of old condylar head fractures (CHFs). This was a retrospective case series study of patients with old CHFs that were treated with open reduction and internal fixation, with anatomic reduction and sutured fixation of the articular disc. Preoperative and postoperative examinations were recorded and analyzed, including temporomandibular joint (TMJ) symptoms, occlusion, maximum interincisal opening (MIO), and mandibular deviation. Computed tomography (CT) was used to assess condylar morphology and position. Eleven patients with old CHFs were included (nine unilateral and two bilateral). The mean period from condylar fracture to operation was 8.9 months (ranging from 6 to 14 months). The mean follow-up period after surgery was 16.1 months (ranging from 12 to 22 months). At the end of follow-up period, no malocclusion was found, and the MIO had expanded considerably to 37.4 ± 3.8 mm. Postoperative CT showed that all fragments were properly reduced and the condyles were in the normal position. All patients showed apparently improved TMJ function, occlusion, and facial appearance. Our results showed that open reduction treatment could be an effective method for the treatment of old CHFs.
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http://dx.doi.org/10.1016/j.jcms.2021.02.026DOI Listing
June 2021

SLC7A11 Reduces Laser-Induced Choroidal Neovascularization by Inhibiting RPE Ferroptosis and VEGF Production.

Front Cell Dev Biol 2021 18;9:639851. Epub 2021 Feb 18.

Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.

In age-related macular degeneration (AMD), one of the principal sources of vascular endothelial growth factor (VEGF) is retinal pigment epithelium (RPE) cells under hypoxia or oxidative stress. Solute carrier family 7 member 11 (SLC7A11), a key component of cystine/glutamate transporter, regulates the level of cellular lipid peroxidation, and restrains ferroptosis. In our study, we assessed the role of SLC7A11 in laser-induced choroidal neovascularization (CNV) and explored the underlying mechanism. We established a mouse model of CNV to detect the expression level of SLC7A11 and VEGF during disease progression. We found the expression of the SLC7A11 protein in RPE cells peaked at 3 days after laser treatment, which was correlated with the expression of VEGF. Intraperitoneal injection of SLC7A11 inhibitor expanded the area of CNV. We examined functional proteins related to oxidative stress and Fe and found laser-induced ferroptosis accompanied by increased Fe content and GPX4 expression in the RPE-choroidal complex after laser treatment. We verified the expression of SLC7A11 in the ARPE19 cell line and the effects of its inhibitors on cell viability and lipid peroxidation . Application of SLC7A11 inhibitor and SLC7A11 knockdown increased the level of lipid peroxidation and reduced the cell viability of ARPE19 which can be rescued by ferroptosis inhibitors ferrostatin-1 (Fer-1) and liproxstatin-1 (Lip-1). Conversely, SLC7A11 overexpression induced resistance to erastin or RSL3-induced ferroptosis. Moreover, we tested the possible regulatory transcription factor NF-E2-related factor 2 (NRF2) of SLC7A11 by Western blot. Knock-down of NRF2 decreased the expression of SLC7A11. Our study suggests that SLC7A11 plays a key role in the laser-induced CNV model by protecting RPE cells from ferroptosis. SLC7A11 provides a new therapeutic target for neovascular AMD patients.
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http://dx.doi.org/10.3389/fcell.2021.639851DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7930391PMC
February 2021

GCN2 Deficiency Enhances Protective Effects of Exercise on Hepatic Steatosis.

Biomed Res Int 2020 24;2020:1454396. Epub 2020 Nov 24.

School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China.

Background: Combined aerobic and resistance training has been demonstrated to benefit glycemic control and reverse nonalcoholic fatty liver disease in childhood obesity. General control nonderepressible 2 (GCN2) deficiency has been reported to attenuate hepatic steatosis and insulin resistance. However, whether GCN2 impacts the positive effects of combined aerobic and resistance exercise remains unknown.

Objectives: To investigate whether combined aerobic and resistance exercise improves hepatic steatosis and glucose intolerance and the role GCN2 plays in mediating the metabolic regulation of exercise.

Methods: Wild-type (WT) and knockout (GCN2KO) mice were fed a high-fat diet (HFD) for 25 weeks. The WT and GCN2KO mice performed exercise (treadmill running + ladder climbing) during the last eight weeks. Their body and liver weights, their triglyceride content, and their levels of aspartate transaminase (AST), alanine transaminase (ALT), and blood glucose were measured, and the expressions of proteins involved in the GCN2/eIF2/ATF4 pathway and the glucolipid metabolism-related proteins (e.g., p-AMPK, SIRT1, PPAR, PGC-1, GLUT4, and p-GSK-3) were determined.

Results: The body weight of WT and GCN2KO mice continued to increase until the end of the experiment. The liver weights, hepatic triglyceride content, and AST and ALT levels of the exercised mice were significantly reduced compared to those of the sedentary mice. Exercise improved blood glucose levels and glucose clearance ability in the WT mice, but the glucose intolerance of GCN2KO mice was not improved. Exercise increased PGC-1, GLUT4, and p-GSK-3 expressions in the WT rather than the GCN2KO mice. Interestingly however, exercise-trained GCN2KO mice were better protected against hepatic steatosis with downregulated expressions of p-eIF2 and ATF4, upregulated expressions of p-AMPK and SIRT1, and the presence of PPAR in the liver, compared to the exercised WT mice.

Conclusion: Combined aerobic and resistance exercise had positive effects on hepatic steatosis and the control of glucose intolerance. GCN2 was found to be necessary for exercise-induced improved glucose intolerance. However, the better efficacy in improving hepatic steatosis by exercise in the -deficient mice enhanced liver lipid metabolism, at least partially, via the AMPK/SIRT1/PPAR pathway.
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http://dx.doi.org/10.1155/2020/1454396DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7707946PMC
May 2021

Photoreceptors Degenerate Through Pyroptosis After Experimental Retinal Detachment.

Invest Ophthalmol Vis Sci 2020 07;61(8):31

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Purpose: Gasdermin D (GSDMD) is crucial in neuronal pyroptosis. GSDMD-N and GSDMD-C are two subdomains of the protein GSDMD. GSDMD-N is an executor of pyroptosis, and GSDMD-C has an inhibitory effect on pyroptotic cell death. This study evaluated the role of GSDMD in photoreceptor cell pyroptosis caused by retinal detachment (RD).

Methods: RD models were established in rats, and GSDMD cleavage was detected by western blotting. The morphology of photoreceptors was assessed by transmission electron microscopy. Some rats were given subretinal injections of recombinant adeno-associated virus 2/8 (rAAV2/8)-GSDMD-C before RD surgery. We documented the expression of caspase-1 and GSDMD-N in retinas by western blot. Levels of IL-1β, TNF-α, and monocyte chemoattractant protein-1 (MCP-1) were detected by quantitative RT-PCR. The membrane integrity of photoreceptors was evaluated by TOTO-3 iodide staining. Retinal function was measured by electroretinography, and the thickness of the outer nuclear layer was also recorded. We measured the activation of glial fibrillary acidic protein (GFAP), F4/80, and ionized calcium binding adaptor molecule 1 (Iba-1) by immunofluorescence.

Results: The cleavage of GSDMD peaked at 1 day after RD. The administration of rAAV2/8-GSDMD-C reduced the pyroptosis and subsequent apoptosis of photoreceptors and preserved the retinal function after RD. Expression of IL-1, TNF-α, and MCP-1 was decreased in the rAAV2/8-GSDMD-C group. In addition, the activation of GFAP, Iba-1, and F4/80 in retinas was alleviated by administering rAAV2/8-GSDMD-C after RD.

Conclusions: GSDMD participates in the pyroptosis of photoreceptor after RD. Overexpression of GSDMD-C may block GSDMD cleavage and attenuate photoreceptor degeneration.
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http://dx.doi.org/10.1167/iovs.61.8.31DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7425730PMC
July 2020

xCT regulates redox homeostasis and promotes photoreceptor survival after retinal detachment.

Free Radic Biol Med 2020 10 15;158:32-43. Epub 2020 Jul 15.

Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, School of Medicine, 200080, Shanghai, China; Shanghai Key Laboratory of Fundus Diseases, 200080, Shanghai, China; Shanghai Engineering Center for Visual Science and Photomedicine, 200080, Shanghai, China. Electronic address:

Backgrounds: Photoreceptor degeneration underlies various retinal disorders that lead to vision impairment. Currently, no effective medication is available to rescue photoreceptors under disease conditions. Elucidation of the molecular pathways involved in photoreceptor degeneration is a prerequisite for the rational design of therapeutic interventions. Photoreceptors are among the most energy-demanding tissues that require highly active oxidative phosphorylation. Therefore, disruption of metabolic support to photoreceptors results in a redox imbalance and subsequent cell death. We hypothesize that the redox regulatory pathway could be a potential therapeutic target to rescue photoreceptors under disease conditions.

Methods: Experimental retinal detachment was induced in mice. A murine photoreceptor-derived 661w cell line treated with HO was employed as an in vitro model to study the cellular response to oxidative stress. The expression and functional role of xCT, an upstream regulator of redox homeostasis, was assessed in vivo and in vitro. An xCT expression vector was constructed for an in vivo study to evaluate the therapeutic potential of this molecule.

Results: xCT expression was upregulated in detached retina and HO-stimulated 661w cells compared to the control cells. Pharmacological inhibition of xCT by sulfasalazine (SAS) promoted photoreceptor degeneration after retinal detachment and 661w cell death upon HO treatment. Additionally, SAS treatment induced reactive oxidative species (ROS) accumulation, glutathione (GSH) depletion, and glutamate release in 661w cells. In contrast, xCT overexpression via viral infection protected photoreceptors from degeneration after retinal detachment.

Conclusion: We conclude that xCT expression is upregulated in photoreceptors after retinal detachment and plays a neuroprotective role in preserving photoreceptors. Mechanistically, xCT promotes cellular homeostasis by regulating intracellular ROS and GSH levels, which are critical to photoreceptor survival after retinal detachment. Collectively, our findings identify xCT as a potential therapeutic target for protection of photoreceptors under disease conditions.
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http://dx.doi.org/10.1016/j.freeradbiomed.2020.06.023DOI Listing
October 2020

3-Methyladenine Alleviates Experimental Subretinal Fibrosis by Inhibiting Macrophages and M2 Polarization Through the PI3K/Akt Pathway.

J Ocul Pharmacol Ther 2020 10 18;36(8):618-628. Epub 2020 Jun 18.

Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, Shanghai, China.

To explore the effects of 3-methyladenine (3-MA), a selective inhibitor of phosphatidylinositol-3-kinase (PI3K), on experimental subretinal fibrosis (SRF) in mice. The SRF mouse model was established by 532 nm laser photocoagulation at each fundus of mice on day 0. 3-MA was administered every 2 days from day 0 to 35. Immunofluorescence of choroidal flat mounts was performed to evaluate the size of SRF area, local macrophages, and polarization, respectively. Besides, Western blot analysis was carried out to assess the expression levels of macrophage polarization-related genes, Arg-1, Ym-1, and transforming growth factor-β (TGF-β). Co-culture and migration experiments were used to demonstrate the inhibitory effect of 3-MA on fibroblasts. The gene knockout and Western blot analysis were used to explore the signal pathways related to macrophage polarization. Compared with the control group, the 3-MA-treated group showed significantly less size of SRF area. 3-MA treatment reduced both circulating and local macrophages, and counteracted M2 polarization. Moreover, 3-MA inhibited fibroblast recruitment. Mechanistically, we proved that 3-MA inhibits macrophage M2 polarization by suppressing PI3K/Akt signal pathway rather than the PI3K-autophagy-related signal pathway. 3-MA exerts antifibrotic effects on experimental SRF by targeting circulating and local macrophages and M2 polarization, through PI3K/Akt signal pathway. These results support the potential use of 3-MA as a new therapeutic modality for SRF associated with neovascular age-related macular degeneration.
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http://dx.doi.org/10.1089/jop.2019.0112DOI Listing
October 2020

Dimethylarginine dimethylaminohydrolase-1 contributes to exercise-induced cardiac angiogenesis in mice.

Biosci Trends 2020 May 1;14(2):115-122. Epub 2020 Apr 1.

School of Kinesiology, Shanghai University of Sport, Shanghai, China.

Dimethylarginine dimethylaminohydrolase-1 (DDAH1) maintains nitric oxide (NO) bioavailability by degrading asymmetric dimethylarginine (ADMA), which is an endogenous inhibitor of nitric oxide synthase (NOS). It has been well established that DDAH1 and exercise play crucial roles in promoting cardiac angiogenesis under pathological conditions. However, the role of DDAH1 in exercise-induced cardiac angiogenesis remains unclear. In this study, we focused on the change in DDAH1 in response to moderate exercise and the underlying mechanism of exercise-induced cardiac angiogenesis. Eight-week-old male DDAH1 global knockout (KO) mice and DDAH1 mice (wild-type) were randomly divided into sedentary groups (control) and swimming groups (exercise). After eight weeks of swimming at five days per week, all the mice were anesthetized and sacrificed. Histological examination and Western blot analysis were performed. There were low levels of myocardial capillaries in DDAH1 KO mice under control and exercise conditions. Notably, exercise elevated DDAH1 protein expression, as observed by Western blot analysis. The common cardiac angiogenesis biomarkers vascular endothelial growth factor (VEGF) and Caveolin-1 were increased during exercise. A significant difference in VEGF was observed between the DDAH1 KO and wild-type groups. Similarly, increased Caveolin-1 expression was abrogated in DDAH1 KO mice. Furthermore, we tested the R-Ras/AKT/GSK3β signaling pathway to study the underlying molecular mechanism. DDAH1 may regulate the R-Ras/AKT/GSK3β pathway due to distinct protein changes in this pathway in the DDAH1 KO and wild-type groups. Our findings suggest that DDAH1 plays an important role in exercise-induced cardiac angiogenesis by regulating the R-Ras/AKT/GSK3βsignaling pathway.
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http://dx.doi.org/10.5582/bst.2019.01351DOI Listing
May 2020

An improved method for establishment of murine retinal detachment model and its 3D vascular evaluation.

Exp Eye Res 2020 04 29;193:107949. Epub 2020 Jan 29.

Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, School of Medicine, 200080, Shanghai, China; Shanghai Key Laboratory of Fundus Diseases, 200080, Shanghai, China; Shanghai Engineering Center for Visual Science and Photomedicine, 200080, Shanghai, China; National Clinical Research Center for Eye Diseases, 200080, Shanghai, China; Shanghai engineering center for precise diagnosis and treatment of eye diseases, 200080, Shanghai, China. Electronic address:

Retinal detachment (RD) results in disruption of retinal physiology and visual function. Although surgical intervention has been well-developed to restore the retinal anatomic structure, post-op progression of visual function decline is prominent in a large proportion of patients. Therefore, the establishment of a disease model that accurately mimics RD pathogenesis is crucial to mechanistic study and drug screening. General protocols to induce RD in mice are frequently associated with complications leading to model instability and reduced reproducibility. In this study, we established a stable and reproducible mice RD model with a detached area of over 90% and rare complications. Briefly, the modified method was realized by vitreous humor extraction to reduce intraocular pressure, followed by directly-visible hyaluronic acid injection into subretinal space. The detachment of retina was confirmed by fundus photography, and progressive thinning of the outer nuclear layer (ONL) was determined by HE staining. Apoptotic signals were prominent in the ONL. Consistently, visual function was significantly compromised as determined by ERG. Moreover, retinal vasculature appeared to remodel and acquired winding, twisted and dilated structures illustrated by 3D reconstruction. In addition, activation of Müller cells and microglia, and infiltration of blood-derived macrophages were detected locally. Collectively, we have established a modified protocol to model RD with increased stability, reproducibility and fewer complications, and 3D high-resolution imaging and reconstruction of vasculature could provide new tools to evaluate this model.
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http://dx.doi.org/10.1016/j.exer.2020.107949DOI Listing
April 2020

Intraocular VEGF deprivation induces degeneration and fibrogenic response in retina.

FASEB J 2019 12 23;33(12):13920-13934. Epub 2019 Oct 23.

Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.

VEGF is a critical driver of ocular neovascularization under disease conditions. Current therapeutic strategies rely on intraocular delivery of VEGF-antagonizing reagents, which results in sustained suppression of pathogenic vascularization. Although significant advancement has been achieved in VEGF antagonism, substantial adverse effects have been reported in retrospective clinical studies. To study mechanisms for VEGF antagonism-associated adverse effects in visual system, we intravitreally delivered recombinant adeno-associated virus-mediated expression of soluble Fms-related tyrosine kinase-1 (rAAV.sFLT-1), the extracellular domain of VEGF receptor, and analyzed the morphology and functions of retinal tissue. Here, we confirmed that intraocular VEGF antagonism induced retinal degeneration and gliosis. The functional deficit in retinal response to visual stimulation was also demonstrated in rAAV.sFLT-1-treated eyes by electroretinogram. Moreover, high-throughput RNA sequencing analysis suggests that VEGF antagonism activates retinal degeneration, inflammation, and other adverse effects. Taken together, our findings have shed light on pathogenic mechanisms for VEGF antagonism-associated adverse effects and potential therapeutic targets.-Xiao, M., Liu, Y., Wang, L., Liang, J., Wang, T., Zhai, Y., Wang, Y., Liu, S., Liu, W., Luo, X., Wang, F., Sun, X. Intraocular VEGF deprivation induces degeneration and fibrogenic response in retina.
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http://dx.doi.org/10.1096/fj.201901283RRDOI Listing
December 2019

UMSC-derived exosomes promote retinal ganglion cells survival in a rat model of optic nerve crush.

J Chem Neuroanat 2019 03 10;96:134-139. Epub 2019 Jan 10.

Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Fundus Diseases, Shanghai, China; Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China.

Traumatic optic neuropathy or glaucoma lead to retinal ganglion cells loss and cause blindness, and there is no effective therapy strategy by far. Mesenchymal cells from the Wharton's jelly of the umbilical cord (umbilical cord mesenchymal stem cells, UMSCs) and UMSC-derived exosomes (UMSC-Exos) are promising candidates for allogeneic therapy in regenerative medicine, but their effort on optic nerve injury and the underlying mechanism remains undefined. In the present study, we investigated the functions of UMSC-Exos in a rat optic nerve crush (ONC) model. After three times of treatments with an interval of one week, we found that the UMSC-Exos significantly promoted Brn3a retinal ganglion cells (RGCs) survival in retinal ganglion cell layer compared with PBS controls. UMSC-Exos also significantly promoted GFAP glia cells activation in retina and optic nerve. However, no increase of GAP43 axon counts in the optic nerve was found after UMSC-Exos treatment. Thus, our results demonstrate that UMSC-derived exosomes may play a role in neuroprotection by promoting the RGCs survival and glia cells activation but not the axon regeneration.
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http://dx.doi.org/10.1016/j.jchemneu.2019.01.006DOI Listing
March 2019

Modulation of α-adrenoceptor signalling protects photoreceptors after retinal detachment by inhibiting oxidative stress and inflammation.

Br J Pharmacol 2019 03 30;176(6):801-813. Epub 2019 Jan 30.

Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, Shanghai, China.

Background And Purpose: Currently available treatments do not halt progression of photoreceptor death and subsequent visual impairment related to retinal detachment (RD) which is observed in various retinal disorders. This study investigated the neuroprotective effects of two adrenoceptor ligands, the α -adrenoceptor antagonist doxazosin and the α -adrenoceptor agonist guanabenz, against photoreceptor cell death in RD.

Experimental Approach: We used a model of experimental RD in Brown-Norway rats induced by subretinal injection of sodium hyaluronate. Oxidative stress biomarkers and cytokine production were quantified with elisa. Protein expression levels and immunofluorescent labelling were determined in rats with RD and controls for mechanistic elucidation. The effects of systemic (i.p.) administration of doxazosin or guanabenz on photoreceptor apoptosis, retinal histology and electroretinography were evaluated in rats with RD and compared to the effects in vehicle controls.

Key Results: Photoreceptors were the major source of RD-induced ROS overproduction in the rat retina through the regulation of NADPH oxidase. Systemic administration of doxazosin or guanabenz decreased the RD-induced production of ROS and proinflammatory cytokines, including IL-1β and the chemokine CCL2, and suppressed retinal gliosis, resulting in attenuation of photoreceptor death and preservation of retinal structures and functions in RD.

Conclusions And Implications: Our findings point to α-adrenoceptors as novel therapeutic targets to provide photoreceptor protection and suggest that both doxazosin and guanabenz, two FDA-approved drugs, could be further explored to treat retinal diseases.
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http://dx.doi.org/10.1111/bph.14565DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6393234PMC
March 2019

Identification of novel PROM1 mutations responsible for autosomal recessive maculopathy with rod-cone dystrophy.

Graefes Arch Clin Exp Ophthalmol 2019 Mar 26;257(3):619-628. Epub 2018 Dec 26.

Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, 100 Haining Road, Shanghai, 200080, China.

Purpose: To characterize two patients with macular and rod-cone dystrophy and identify the genetic basis for disease.

Method: Ophthalmic examinations were performed for the family and the peripheral blood samples were collected for whole exome sequencing. The mutated sequences of PROM1 gene were cloned and expressed in cultured cell lines after transient transfection followed by analysis with confocal microscopy and bridge-PCR.

Result: We reported that two patients, brothers in a family, were diagnosed with macular and rod-cone dystrophy. Phenotypically, both patients experience progressive visual impairment and nyctalopia. The fundus examination showed macular and choroid dystrophy with pigment deposits in the macular region. Functionally, photoreceptor response to electrophysiological stimulation was significantly compromised with more severe decline in rods. Genetic analysis by whole exome sequencing revealed two novel compound heterogeneous point mutations in PROM1 gene that co-segregate with patients in an autosomal recessive manner. Specifically, the c.C1902G(p.Y634X) nonsense mutation results in a truncated, labile, and mislocalized protein, while the c.C1682+3A>G intronic mutation disrupts messenger RNA splicing.

Conclusion: Our findings have identified two novel deleterious mutations in PROM1 gene that are associated with hereditary macular and rod-cone dystrophy in human.
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http://dx.doi.org/10.1007/s00417-018-04206-wDOI Listing
March 2019

DNMT1 and Sp1 competitively regulate the expression of BACE1 in A2E-mediated photo-oxidative damage in RPE cells.

Neurochem Int 2018 12 28;121:59-68. Epub 2018 Sep 28.

Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China; Shanghai Key Laboratory of Fundus Disease, Shanghai, People's Republic of China. Electronic address:

Numerous studies have focused on the deteriorate role of amyloid-β (Aβ) on retina, implying the potential pathogenic mechanism underlying age-related macular degeneration (AMD). However, the mechanism underlying the Aβ deposition in AMD patients remains unknown. Beta-site amyloid precursor protein-cleaving enzyme 1 (BACE1), rate-limiting enzyme for Aβ production, plays an important role in Aβ deposition in the brain. In the current study, we aimed to clarify the regulation mechanism of BACE1 and explore potential drug targets using a lipofuscinfluorophore A2E-mediated photo-oxidation model. In this model, Aβ and Aβ levels increased simultaneously with the enhanced BACE1 expression. These changes were associated with the hypomethylation of specific loci within the BACE1 gene promoter and the decreased levels of DNA methyltransferase 1 (DNMT1). Furthermore, we noticed overlapping regions of differentially methylated CpG islands and specificity protein (Sp1) binding sites within the BACE1 promoter. We employed chromatin immunoprecipitation (ChIP) assay to verify that the decreased BACE1 promoter methylation by DNMT1 enabled increased binding between Sp1 and the BACE1 promoter, which further enhanced BACE1 transcription. The inhibition of Sp1 with mithramycin A (MTM) could down-regulate the expression of BACE1 as well as alleviate the RPE barrier morphology and function impairment. Our results for the first time show the competitive regulation of BACE1 by transcription factor Sp1 and DNMT1 after photo-oxidation and confirm the potential novel protective role of MTM on RPE cells.
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http://dx.doi.org/10.1016/j.neuint.2018.09.001DOI Listing
December 2018

Inhibition of notch signaling pathway temporally postpones the cartilage degradation progress of temporomandibular joint arthritis in mice.

J Craniomaxillofac Surg 2018 Jul 2;46(7):1132-1138. Epub 2018 May 2.

State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthognathic and TMJ Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China. Electronic address:

Purpose: The aim of this study is to explore the role of Notch signaling pathway in the initiation and progression of temporomandibular joint osteoarthritis (TMJOA).

Methods: 48 mice were divided into DAPT-TMJOA, Control-TMJOA and Control-Sham groups. Animals received discectomy/Sham surgery in their right TMJ, following the DAPT/saline intra-articular injections every week. Mice were sacrificed at 1/4/8 weeks post-surgery. Safranin-O and H&E staining were performed on the TMJ sections for the modified Mankin's score. qPCR and immunohistochemistry were used to evaluate Notch1, Jagged1 and Hes5 expressions.

Results: The mRNA expressions of Notch1, Jagged1 and Hes5 were significantly increased in Control-TMJOA group compared with Control-Sham group. Immunostaining revealed a dramatic elevation of Notch1, Jagged1 and Hes5 signals distributed in the cartilage at 1 and 4 weeks after discectomy. However, the increased number of those immuno-positive cells turned down at 8 weeks after surgery. DAPT treatment partially rescued the elevated mRNA expression and immuno-positive cell numbers of Notch1, Jagged1 and Hes5. More importantly, the cartilage destruction during TMJOA was delayed by DAPT treatment, analyzed by modified Mankin's score.

Conclusion: Notch signaling participates in the onset and development of TMJOA. Inhibiting Notch signaling activation by DAPT can partially delay the progress of TMJOA.
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http://dx.doi.org/10.1016/j.jcms.2018.04.026DOI Listing
July 2018

Inhibition of Mitochondrial Fission Preserves Photoreceptors after Retinal Detachment.

Am J Pathol 2018 07 22;188(7):1713-1722. Epub 2018 Apr 22.

Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, Shanghai; Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai; Shanghai Key Laboratory of Fundus Diseases, Shanghai, People's Republic of China. Electronic address:

Photoreceptor degeneration is a leading cause of visual impairment worldwide. Separation of neurosensory retina from the underlying retinal pigment epithelium is a prominent feature preceding photoreceptor degeneration in a variety of retinal diseases. Although ophthalmic surgical procedures have been well developed to restore retinal structures, postoperative patients usually experience progressive photoreceptor degeneration and irreversible vision loss that is incurable at present. Previous studies point to a critical role of mitochondria-mediated apoptotic pathway in photoreceptor degeneration, but the upstream triggers remain largely unexplored. In this study, we show that after experimental retinal detachment induction, photoreceptors activate dynamin-related protein 1 (Drp1)-dependent mitochondrial fission pathway and subsequent apoptotic cascades. Mechanistically, endogenous reactive oxygen species (ROS) are necessary for Drp1 activation in vivo, and exogenous ROS insult is sufficient to activate Drp1-dependent mitochondrial fission in cultured photoreceptors. Accordingly, inhibition of Drp1 activity effectively preserves mitochondrial integrity and rescues photoreceptors. Collectively, our data delineate an ROS-Drp1-mitochondria axis that promotes photoreceptor degeneration in retinal diseased models.
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http://dx.doi.org/10.1016/j.ajpath.2018.03.013DOI Listing
July 2018

Choroidal pericytes promote subretinal fibrosis after experimental photocoagulation.

Dis Model Mech 2018 04 23;11(4). Epub 2018 Apr 23.

Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, 100 Haining Road, Shanghai 200080, China

Subretinal fibrosis results in local destruction of retinal structures and permanent vision loss, representing the end stage of neovascular age-related macular degeneration (AMD). Histological examination of fibrotic specimens from AMD patients has uncovered a wide range of cellular and acellular components. However, their origins and roles in fibrosis remain largely unexplored. Using a laser-induced photocoagulation model with collagen 1α1-GFP reporter mice, we demonstrate, by cell-lineage tracing, that pericytes associating with choroidal microvasculature are activated upon injury and infiltrate into the subretinal space as significant components of fibrotic lesions. In contrast to their choroidal precursors, infiltrating pericytes acquire stellate-like structures, upregulate expression of fibrogenic molecules and colocalize with extracellular fibrotic scar. Collectively, our results identify the choroidal perivascular niche as a novel source of subretinal fibrosis after photocoagulation, and suggest that collagen 1-expressing pericytes are potential targets for therapeutic intervention to suppress subretinal fibrosis and preserve vision.
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http://dx.doi.org/10.1242/dmm.032060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5963858PMC
April 2018

Photosensitization of A2E triggers telomere dysfunction and accelerates retinal pigment epithelium senescence.

Cell Death Dis 2018 02 7;9(2):178. Epub 2018 Feb 7.

Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, No. 100 HaiNing Road, 200080, Shanghai, PR China.

Age-related macular degeneration (AMD) is the leading cause of irreversible vision loss in elderly people. AMD is classified as early, intermediate, advanced non-neovascular, and advanced neovascular forms depending on the clinical features. However, the exact pathogenesis remains unclear. Retinal pigment epithelium (RPE) cells degeneration is a hallmark of AMD. With aging, lipofuscin accumulates in RPE cells. N-retinylidene-N-retinylethanolamine (named A2E), a well-known fluorophore of lipofuscin, may contribute to RPE cells degeneration. In this study, we showed that photosensitization of A2E increased DNA damage, including telomere deprotection and deletion, and triggered cellular senescence. In addition, we found that the antioxidant N-acetyl-cysteine (NAC) partially alleviated this DNA damage. Telomerase overexpression rescued A2E-mediated RPE cell senescence, indicating that telomere dysfunction plays an important role in A2E-based senescence. We further showed that the senescence induced by A2E photosensitization may affect the microenvironment of the retina by expressing several factors of the secretory phenotype (SASP) including IL1B, IL13RA2, and CXCR4 through the NF-κB pathway. We propose that expression of these factors create a pro-inflammatory environment that drives retina degeneration. Moreover, our findings suggest that protecting telomeres is a valuable strategy for treating retinal degeneration diseases, such as AMD.
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http://dx.doi.org/10.1038/s41419-017-0200-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5833825PMC
February 2018

Autophagy activated by SIRT6 regulates Aβ induced inflammatory response in RPEs.

Biochem Biophys Res Commun 2018 02 31;496(4):1148-1154. Epub 2018 Jan 31.

Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Fundus Diseases, Shanghai, China; Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China. Electronic address:

Age-associated dysfunction of retinal pigment epithelial cells (RPEs) is considered to be the initial trigger of retinal diseases such as age-related macular degeneration. Although autophagy is upregulated in RPEs during the course of aging, little is known about how autophagy is regulated and its functional role in RPEs. In this study, we found that expression of Sirtuin 6 (SIRT6) and autophagic markers are upregulated in RPEs of aged mice where subretinal deposition of amyloid-β is accumulated and in amyloid-β stimulated RPEs. In addition, gain and loss-of-function studies confirmed the positive role of SIRT6 in regulating autophagy. Interesting, inhibition of autophagy attenuates amyloid-β stimulated inflammatory response in RPEs. Collectively, our findings uncover the autophagy modulated by SIRT6 may be a proinflammatory mechanism for amyloid-β induced RPE dysfunction.
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http://dx.doi.org/10.1016/j.bbrc.2018.01.159DOI Listing
February 2018

Cooperation of Rel family members in regulating Aβ-mediated pro-inflammatory cytokine secretion by retinal pigment epithelial cells.

Cell Death Dis 2017 10 12;8(10):e3115. Epub 2017 Oct 12.

Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), School of Medicine, Shanghai Jiao Tong University, Shanghai, China.

Amyloid-beta (Aβ) is a hallmark component of age-related macular degeneration (AMD), which induces secretion of pro-inflammatory cytokines from retinal pigment epithelium (RPE). Previous studies have shown that p50/RelA (p65), a member of NF-κB family, is an essential pro-inflammatory transcription factor responding to Aβ stimulation, but few focused on the other two Rel transcription factor members - RelB and c-Rel - and their role in Aβ-mediated inflammation. It was reported that RelA, RelB and c-Rel are also implicated in various NF-κB-mediated inflammatory diseases. Therefore, we infer that Aβ-mediated inflammation targets not only the classical inflammation regulator, RelA, but also RelB and c-Rel. In this study, we demonstrate that intravitreally injected Aβ mice develop AMD-like pathologic changes, coupled with Rel protein (RelA, RelB and c-Rel) synthesis and nuclear translocation. To focus on the interaction mechanism of Rel proteins, we found that RelB and c-Rel formed a heterodimer with RelA in mice model. We also found that c-Rel silencing decreased the levels of Aβ-dependent RelA expression, indicating that RelB and c-Rel may interact with RelA as coactivator and c-Rel is required to activate the expression of RelA. Moreover, Rel protein silencing decreased the expression of distinct pro-inflammatory cytokines. Together, we demonstrate that besides RelA, RelB and c-Rel can also be activated by Aβ, all of which mediate pro-inflammatory cytokine transcription and RPE damage. Our findings imply that RPE-mediated inflammation under the stimulation of Aβ is multi-targeted and RelA, RelB and c-Rel proteins may be the new targets of anti-inflammatory agents.
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http://dx.doi.org/10.1038/cddis.2017.502DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5682668PMC
October 2017

MicroRNA-155 Inhibits Polarization of Macrophages to M2-Type and Suppresses Choroidal Neovascularization.

Inflammation 2018 Feb;41(1):143-153

Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, School of Medicine, Shanghai, 200080, China.

Arg-1Ym-1 M2-type macrophages play essential roles in the development of choroidal neovascularization (CNV). Thus, inhibition of M2-type macrophages may be effective in suppressing CNV. However, the potential mechanisms of macrophage polarization during development of CNV remain unclear. In this study, we report that microRNA-155 (miR-155) inhibited M2 polarization by targeting C/EBPβ in CNV model mice and in bone marrow-derived primary macrophages. Moreover, our data show that intravitreous injection of miR-155 mimics suppressed subretinal leakage and neovascularization. Therefore, we conclude that C/EBPβ plays a significant role in M2 macrophage polarization in CNV model, while miR-155 mimics could suppress CNV by inhibiting C/EBPβ activity and M2 macrophage polarization.
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http://dx.doi.org/10.1007/s10753-017-0672-8DOI Listing
February 2018

MicroRNA Expression Patterns Involved in Amyloid Beta-Induced Retinal Degeneration.

Invest Ophthalmol Vis Sci 2017 03;58(3):1726-1735

Department of Ophthalmology, Shanghai First People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China 2Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China 3Shanghai Key Laboratory of Fundus Diseases, Shanghai, People's Republic of China.

Purpose: Dry age-related macular degeneration (AMD) is characterized by the accumulation of drusen under Bruch's membrane, and amyloid beta (Aβ) is speculated to be one of the key pathologic factors. While the detrimental effects of Aβ on retinas have been widely explored, Aβ-induced epigenetic regulatory changes have yet to be fully investigated. We therefore aimed to identify the microRNA (miRNA) expression profiles in an Aβ-induced mouse model of retinal degeneration.

Methods: C57BL/6 mice were intravitreally injected with Aβ1-40 or PBS and the eye tissues were collected for hematoxylin and eosin (H&E) staining, apoptosis immunofluorescence staining, and miRNA profiling. After filtering, 10 miRNAs and their target genes were chosen for quantitative RT-PCR (qRT-PCR) confirmations. Pathway analyses were employed for further bioinformatic analyses.

Results: Hematoxylin and eosin-stained sections of retinal pigment epithelium (RPE)/neural retina tissue demonstrated degenerative alterations, and immunofluorescence testing revealed apoptosis within the retina after Aβ treatments. MicroRNA profiling revealed 61 miRNAs that were differentially expressed between the model and the control group. Among these, 38 miRNAs were upregulated (fold change > 1.5, P < 0.05) and 23 miRNAs were downregulated (fold change < 0.667, P < 0.05). Five of the 10 selected miRNAs (miR-142, miR-216, miR-155, miR-223, and miR-433) as well as several key target genes (CFH, IGF-1R, c-MET, and ABCA1) were confirmed by qRT-PCR analyses.

Conclusions: Our study is the first to profile the miRNA expression patterns and suggests that Aβ accumulation could lead to relevant biochemical alternations such as complement activation, barrier impairment, apoptosis, and positive feedback of Aβ production.
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http://dx.doi.org/10.1167/iovs.16-20043DOI Listing
March 2017

Involvement of XBP1s in Blue Light-Induced A2E-Containing Retinal Pigment Epithelium Cell Death.

Ophthalmic Res 2017 19;57(4):252-262. Epub 2017 Jan 19.

Department of Ophthalmology, Shanghai First People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.

Purpose: Retinal pigment epithelium (RPE) cell dysfunction is essential to the development of retinal degenerative disease. This study was designed to investigate how spliced X-box-binding protein 1 (XBP1s) regulates different modes of RPE cell death in vitro.

Methods: Human ARPE19 cells were incubated with 25 μM N-retinylidene-N-retinylethanolamine (A2E) and irradiated with blue light. Expressions of glucose-regulated protein 78 (GRP78) and XBP1s were detected by real-time quantitative PCR and Western blot. STF-083010 was used to suppress XBP1s expression. ARPE19 cell apoptosis was assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling and flow cytometry. Receptor-interacting protein kinase-3 (RIP3) was detected by Western blot. Changes in the morphology of ARPE19 cells were identified by transmission electron microscopy.

Results: Blue light-induced A2E-containing ARPE19 cell damage caused a transient elevation of GRP78 and XBP1s, while RIP3 rose in the late stage. STF-083010 effectively inhibited XBP1s expression and brought about the aggravation of apoptosis together with an alleviation of RIP3 expression. Most of the dying cells exhibited apoptotic morphology.

Conclusion: A2E, along with blue light, brought about apoptosis and necroptosis of ARPE19 cells, and XBP1s was transiently elevated. The suppression of XBP1s induced ARPE19 cell death by promoting apoptosis rather than necroptosis. XBP1s might play a role in the pathogenesis of retinal degenerative diseases.
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http://dx.doi.org/10.1159/000452282DOI Listing
May 2017

Antiangiogenic Effects of Doxazosin on Experimental Choroidal Neovascularization in Mice.

J Ocul Pharmacol Ther 2017 Jan/Feb;33(1):50-56. Epub 2016 Dec 19.

1 Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai, China .

Purpose: The present study was designed to evaluate the effects of doxazosin on experimental choroidal neovascularization (CNV) in mice.

Methods: Six- to 8-week-old male C57BL/6 mice were divided into a control group and a doxazosin-treated group (5 mg/kg, i.p., daily). Experimental CNV was induced by laser photocoagulation. Seven and 14 days after laser induction, fluorescein angiography, choroidal flat mounts, and histological studies were performed to evaluate the fluorescence leakage, area, and thickness of CNV lesions, respectively. In addition, western blot analysis was carried out to assess the inhibitory effects of doxazosin on the PI3K/Akt/mTOR signaling pathway and the expression levels of hypoxia-inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF), which are involved in CNV model.

Results: Compared with the control group, the doxazosin-treated group demonstrated significantly less fluorescence leakage on day 7 and 14 after laser induction. Both the area and the thickness of CNV lesions in the doxazosin-treated group were significantly decreased. Mechanistically, PI3K/Akt/mTOR signaling pathway activation was significantly suppressed in the doxazosin-treated group. The expression of HIF-1α and VEGF was also notably reduced by systemic doxazosin treatment.

Conclusions: Doxazosin exerts antiangiogenic actions in an experimental mouse model of CNV and may be a potential adjunctive therapy for neovascular age-related macular degeneration in humans.
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http://dx.doi.org/10.1089/jop.2016.0153DOI Listing
November 2017

Virally delivered, constitutively active NFκB improves survival of injured retinal ganglion cells.

Eur J Neurosci 2016 12 13;44(11):2935-2943. Epub 2016 Sep 13.

Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.

As axon damage and retinal ganglion cell (RGC) loss lead to blindness, therapies that increase RGC survival and axon regrowth have direct clinical relevance. Given that NFκB signaling is critical for neuronal survival and may regulate neurite growth, we investigated the therapeutic potential of NFκB signaling in RGC survival and axon regeneration. Although both NFκB subunits (p65 and p50) are present in RGCs, p65 exists in an inactive (unphosphorylated) state when RGCs are subjected to neurotoxic conditions. In this study, we used a phosphomimetic approach to generate DNA coding for an activated (phosphorylated) p65 (p65mut), then employed an adeno-associated virus serotype 2 (AAV2) to deliver the DNA into RGCs. We tested whether constitutive p65mut expression prevents death and facilitates neurite outgrowth in RGCs subjected to transient retinal ischemia or optic nerve crush (ONC), two models of neurotoxicity. Our data indicate that RGCs treated with AAV2-p65mut displayed a significant increase in survival compared to controls in ONC model (77 ± 7% vs. 25 ± 3%, P-value = 0.0001). We also found protective effect of modified p65 in RGCs of ischemic retinas (55 ± 12% vs. 35 ± 6%), but not to a statistically significant degree (P-value = 0.14). We did not detect a difference in axon regeneration between experimental and control animals after ONC. These findings suggest that increased NFκB signaling in RGCs attenuates retinal damage in animal models of neurodegeneration, but insignificantly impacts axon regeneration.
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http://dx.doi.org/10.1111/ejn.13383DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5138106PMC
December 2016

Retinal ganglion cell survival and axon regeneration after optic nerve injury in naked mole-rats.

J Comp Neurol 2017 02 17;525(2):380-388. Epub 2016 Jul 17.

F.M. Kirby Neurobiology Center, Children's Hospital, and Department of Neurology, Harvard Medical School, Boston, Massachusetts, 02115.

In the adult mammalian central nervous system (CNS), axonal damage often triggers neuronal cell death and glial activation, with very limited spontaneous axon regeneration. In this study, we performed optic nerve injury in adult naked mole-rats, the longest living rodent, with a maximum life span exceeding 30 years, and found that injury responses in this species are quite distinct from those in other mammalian species. In contrast to what is seen in other mammals, the majority of injured retinal ganglion cells (RGCs) survive with relatively high spontaneous axon regeneration. Furthermore, injured RGCs display activated signal transducer and activator of transcription-3 (STAT3), whereas astrocytes in the optic nerve robustly occupy and fill the lesion area days after injury. These neuron-intrinsic and -extrinsic injury responses are reminiscent of those in "cold-blooded" animals, such as fish and amphibians, suggesting that the naked mole-rat is a powerful model for exploring the mechanisms of neuronal injury responses and axon regeneration in mammals. J. Comp. Neurol. 525:380-388, 2017. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/cne.24070DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6422164PMC
February 2017

Hyperactivated Stat3 boosts axon regeneration in the CNS.

Exp Neurol 2016 06 6;280:115-20. Epub 2016 Apr 6.

Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Center for Computational Science, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA. Electronic address:

Axonal regeneration after spinal cord injury (SCI) is intrinsically and extrinsically inhibited by multiple factors. One major factor contributing to intrinsic regeneration failure is the inability of mature neurons in the central nervous system (CNS) to activate regeneration-associated transcription factors (TFs) post-injury. A prior study identified TFs overexpressed in neurons of the peripheral nervous system (PNS) compared to the CNS; some of these could be involved in the ability of PNS neurons to regenerate. Of these, signal transducer and activator of transcription 3 (STAT3), as well its downstream regeneration-associated targets, showed a significant upregulation in PNS neurons relative to CNS neurons, and a constitutively active variant of Stat3 (Stat3CA) promoted neurite growth when expressed in cerebellar neurons (Lerch et al., 2012; Smith et al., 2011). To further enhance STAT3's neurite outgrowth enhancing activity, Stat3CA was fused with a viral activation domain (VP16). VP16 hyperactivates TFs by recruiting transcriptional co-factors to the DNA binding domain (Hirai et al., 2010). Overexpression of this VP16-Stat3CA chimera in primary cortical neurons led to a significant increase of neurite outgrowth as well as Stat3 transcriptional activity in vitro. Furthermore, in vivo transduction of retinal ganglion cells (RGCs) with AAV constructs expressing VP16-Stat3CA resulted in regeneration of optic nerve axons after injury, to a greater degree than for those expressing Stat3CA alone. These findings confirm and extend the concept that overexpression of hyperactivated transcription factors identified as functioning in PNS regeneration can promote axon regeneration in the CNS.
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http://dx.doi.org/10.1016/j.expneurol.2016.03.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4888791PMC
June 2016

Enhanced Transcriptional Activity and Mitochondrial Localization of STAT3 Co-induce Axon Regrowth in the Adult Central Nervous System.

Cell Rep 2016 Apr 31;15(2):398-410. Epub 2016 Mar 31.

Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA. Electronic address:

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor central to axon regrowth with an enigmatic ability to act in different subcellular regions independently of its transcriptional roles. However, its roles in mature CNS neurons remain unclear. Here, we show that along with nuclear translocation, STAT3 translocates to mitochondria in mature CNS neurons upon cytokine stimulation. Loss- and gain-of-function studies using knockout mice and viral expression of various STAT3 mutants demonstrate that STAT3's transcriptional function is indispensable for CNS axon regrowth, whereas mitochondrial STAT3 enhances bioenergetics and further potentiates regrowth. STAT3's localization, functions, and growth-promoting effects are regulated by mitogen-activated protein kinase kinase (MEK), an effect further enhanced by Pten deletion, leading to extensive axon regrowth in the mouse optic pathway and spinal cord. These results highlight CNS neuronal dependence on STAT3 transcriptional activity, with mitochondrial STAT3 providing ancillary roles, and illustrate a critical contribution for MEK in enhancing diverse STAT3 functions and axon regrowth.
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http://dx.doi.org/10.1016/j.celrep.2016.03.029DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4833545PMC
April 2016

The complete mitochondrial genome of Southern pig-tailed macaque, Macaca nemestrina, and comparative mitochondrial genomics of Macaca species.

Mitochondrial DNA A DNA Mapp Seq Anal 2016 07 22;27(4):2363-4. Epub 2015 May 22.

a Clinical School of University of Hubei Chinese Medicine , Wuhan , Hubei , China and.

In this study, we report the complete mitochondrial genome sequence of Southern pig-tailed, Macaca nemestrina for the first time. The genome is found to be 16,560 bp in length and has a base composition of A (32.25%), G (12.31%), C (30.51%), and T (24.93%), indicating that the percentage of A + T (57.18%) was higher than G + C (42.82%). Similar to other monkeys, it contains a typically conserved structure including 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and 1 control region (D-loop). Most of the genes were located on the H-strand except for the ND6 gene and 8 tRNA genes. To obtain a more complete understanding of the evolutionary history of Macaca genus, 11 mitochondrial genomes were used for phylogenetic analysis. This mitochondrial sequence reported here would be useful to uncover the monkey's evolution and add a new genetic resource for the genus Macaca.
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http://dx.doi.org/10.3109/19401736.2015.1025265DOI Listing
July 2016
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