The unfolded protein response is a cellular pathway activated to maintain proteostasis and prevent cell death when the endoplasmic reticulum is overwhelmed by unfolded proteins.However,if the unfolded protein response...The unfolded protein response is a cellular pathway activated to maintain proteostasis and prevent cell death when the endoplasmic reticulum is overwhelmed by unfolded proteins.However,if the unfolded protein response fails to restore endoplasmic reticulum homeostasis,it can trigger proinflammatory and pro-death signals,which are implicated in various malignancies and are currently being investigated for their role in retinal degenerative diseases.This paper reviews the role of the unfolded protein responsein addressing endoplasmic reticulumstress in retinal degenerative diseases.The accumulation of ubiquitylated misfolded proteins can lead to rapid destabilization of the proteome and cellular demise.Targeting endoplasmic reticulum stress to alleviate retinal pathologies involves multiple strategies,including the use of chemical chaperones such as 4-phenylbutyric acid and tauroursodeoxycholic acid,which enhance protein folding and reduce endoplasmic reticulum stress.Small molecule modulators that influence endoplasmic reticulum stress sensors,including those that increase the expression of the endoplasmic reticulum stress regulator X-box binding protein 1,are also potential therapeutic agents.Additionally,inhibitors of the RNAse activity of inositol-requiring transmembrane kinase/endoribonuclease 1,a key endoplasmic reticulum stress sensor,represent another class of drugs that could prevent the formation of toxic aggregates.The activation of nuclear receptors,such as PPAR and FXR,may also help mitigate ER stress.Furthermore,enhancing proteolysis through the induction of autophagy or the inhibition of deubiquitinating enzymes can assist in clearing misfolded proteins.Combination treatments that involve endoplasmicreticulum-stress-targeting drugs and gene therapies are also being explored.Despite these potential therapeutic strategies,significant challenges remain in targeting endoplasmic reticulum stress for the treatment of retinal degeneration,and further research is essential to elucidate the mechanisms underlying human retinal diseases and to develop effective,well-tolerated drugs.The use of existing drugs that target inositol-requiring transmembrane kinase/endoribonuclease 1 and X-box binding protein 1 has been associated with adverse side effects,which have hindered their clinical translation.Moreover,signaling pathways downstream of endoplasmic reticulum stress sensors can contribute to therapy resistance.Addressing these limitations is crucial for developing drugs that can be effectively used in treating retinal dystrophies.In conclusion,while the unfolded protein response is a promising therapeutic target in retinal degenerative diseases,additional research and development efforts are imperative to overcome the current limitations and improve patient outcomes.展开更多
Traumatic optic neuropathy is a form of optic neuropathy resulting from trauma.Its pathophysiological mechanisms involve primary and secondary injury phases,leading to progressive retinal ganglion cell loss and axonal...Traumatic optic neuropathy is a form of optic neuropathy resulting from trauma.Its pathophysiological mechanisms involve primary and secondary injury phases,leading to progressive retinal ganglion cell loss and axonal degeneration.Contributing factors such as physical trauma,oxidative stress,neuroinflammation,and glial scar formation exacerbate disease progression and retinal ganglion cell death.Multiple forms of cell death—including apoptosis,pyroptosis,necroptosis,and ferroptosis—are involved at different disease stages.Although current treatments,such as corticosteroid therapy and surgical interventions,have limited efficacy,cell-based therapies have emerged as a promising approach that simultaneously promotes neuroprotection and retinal ganglion cell regeneration.This review summarizes recent advances in cell-based therapies for traumatic optic neuropathy.In the context of cell replacement therapy,retinal ganglion cell-like cells derived from embryonic stem cells and induced pluripotent stem cells—via chemical induction or direct reprogramming—have demonstrated the ability to integrate into the host retina and survive for weeks to months,potentially improving visual function.Mesenchymal stem cells derived from various sources,including bone marrow,umbilical cord,placenta,and adipose tissue,have been shown to enhance retinal ganglion cell survival,stimulate axonal regeneration,and support partial functional recovery.Additionally,neural stem/progenitor cells derived from human embryonic stem cells offer neuroprotective effects and function as“neuronal relays,”facilitating reconnection between damaged regions of the optic nerve and the visual pathway.Beyond direct cell transplantation,cell-derived products,such as extracellular vesicles and cell-extracted solutions,have demonstrated promising neuroprotective effects in traumatic optic neuropathy.Despite significant progress,several challenges remain,including limited integration of transplanted cells,suboptimal functional vision recovery,the need for precise timing and delivery methods,and an incomplete understanding of the role of the retinal microenvironment and glial cell activation in neuroprotection and neuroregeneration.Furthermore,studies with longer observation periods and deeper mechanistic insights into the therapeutic effects of cell-based therapies remain scarce.Two Phase I clinical trials have confirmed the safety and potential benefits of cell-based therapy for traumatic optic neuropathy,with reported improvements in visual acuity.However,further studies are needed to validate these findings and establish significant therapeutic outcomes.In conclusion,cell-based therapies hold great promise for treating traumatic optic neuropathy,but critical obstacles must be overcome to achieve functional optic nerve regeneration.Emerging bioengineering strategies,such as scaffold-based transplantation,may improve cell survival and axonal guidance.Successful clinical translation will require rigorous preclinical validation,standardized protocols,and the integration of advanced imaging techniques to optimize therapeutic efficacy.展开更多
Retinal ganglion cells are the bridging neurons between the eye and the central nervous system,transmitting visual signals to the brain.The injury and loss of retinal ganglion cells are the primary pathological change...Retinal ganglion cells are the bridging neurons between the eye and the central nervous system,transmitting visual signals to the brain.The injury and loss of retinal ganglion cells are the primary pathological changes in several retinal degenerative diseases,including glaucoma,ischemic optic neuropathy,diabetic neuropathy,and optic neuritis.In mammals,injured retinal ganglion cells lack regenerative capacity and undergo apoptotic cell death within a few days of injury.Additionally,these cells exhibit limited regenerative ability,ultimately contributing to vision impairment and potentially leading to blindness.Currently,the only effective clinical treatment for glaucoma is to prevent vision loss by lowering intraocular pressure through medications or surgery;however,this approach cannot halt the effect of retinal ganglion cell loss on visual function.This review comprehensively investigates the mechanisms underlying retinal ganglion cell degeneration in retinal degenerative diseases and further explores the current status and potential of cell replacement therapy for regenerating retinal ganglion cells.As our understanding of the complex processes involved in retinal ganglion cell degeneration deepens,we can explore new treatment strategies,such as cell transplantation,which may offer more effective ways to mitigate the effect of retinal degenerative diseases on vision.展开更多
Our previous study demonstrated that combined transplantation of bone marrow mesenchymal stem cells and retinal progenitor cells in rats has therapeutic effects on retinal degeneration that are superior to transplanta...Our previous study demonstrated that combined transplantation of bone marrow mesenchymal stem cells and retinal progenitor cells in rats has therapeutic effects on retinal degeneration that are superior to transplantation of retinal progenitor cells alone.Bone marrow mesenchymal stem cells regulate and interact with various cells in the retinal microenvironment by secreting neurotrophic factors and extracellular vesicles.Small extracellular vesicles derived from bone marrow mesenchymal stem cells,which offer low immunogenicity,minimal tumorigenic risk,and ease of transportation,have been utilized in the treatment of various neurological diseases.These vesicles exhibit various activities,including anti-inflammatory actions,promotion of tissue repair,and immune regulation.Therefore,novel strategies using human retinal progenitor cells combined with bone marrow mesenchymal stem cell-derived small extracellular vesicles may represent an innovation in stem cell therapy for retinal degeneration.In this study,we developed such an approach utilizing retinal progenitor cells combined with bone marrow mesenchymal stem cell-derived small extracellular vesicles to treat retinal degeneration in Royal College of Surgeons rats,a genetic model of retinal degeneration.Our findings revealed that the combination of bone marrow mesenchymal stem cell-derived small extracellular vesicles and retinal progenitor cells significantly improved visual function in these rats.The addition of bone marrow mesenchymal stem cell-derived small extracellular vesicles as adjuvants to stem cell transplantation with retinal progenitor cells enhanced the survival,migration,and differentiation of the exogenous retinal progenitor cells.Concurrently,these small extracellular vesicles inhibited the activation of regional microglia,promoted the migration of transplanted retinal progenitor cells to the inner nuclear layer of the retina,and facilitated their differentiation into photoreceptors and bipolar cells.These findings suggest that bone marrow mesenchymal stem cell-derived small extracellular vesicles potentiate the therapeutic efficacy of retinal progenitor cells in retinal degeneration by promoting their survival and differentiation.展开更多
The human retina,a complex and highly specialized structure,includes multiple cell types that work synergistically to generate and transmit visual signals.However,genetic predisposition or age-related degeneration can...The human retina,a complex and highly specialized structure,includes multiple cell types that work synergistically to generate and transmit visual signals.However,genetic predisposition or age-related degeneration can lead to retinal damage that severely impairs vision or causes blindness.Treatment options for retinal diseases are limited,and there is an urgent need for innovative therapeutic strategies.Cell and gene therapies are promising because of the efficacy of delivery systems that transport therapeutic genes to targeted retinal cells.Gene delivery systems hold great promise for treating retinal diseases by enabling the targeted delivery of therapeutic genes to affected cells or by converting endogenous cells into functional ones to facilitate nerve regeneration,potentially restoring vision.This review focuses on two principal categories of gene delivery vectors used in the treatment of retinal diseases:viral and non-viral systems.Viral vectors,including lentiviruses and adeno-associated viruses,exploit the innate ability of viruses to infiltrate cells,which is followed by the introduction of therapeutic genetic material into target cells for gene correction.Lentiviruses can accommodate exogenous genes up to 8 kb in length,but their mechanism of integration into the host genome presents insertion mutation risks.Conversely,adeno-associated viruses are safer,as they exist as episomes in the nucleus,yet their limited packaging capacity constrains their application to a narrower spectrum of diseases,which necessitates the exploration of alternative delivery methods.In parallel,progress has also occurred in the development of novel non-viral delivery systems,particularly those based on liposomal technology.Manipulation of the ratios of hydrophilic and hydrophobic molecules within liposomes and the development of new lipid formulations have led to the creation of advanced non-viral vectors.These innovative systems include solid lipid nanoparticles,polymer nanoparticles,dendrimers,polymeric micelles,and polymeric nanoparticles.Compared with their viral counterparts,non-viral delivery systems offer markedly enhanced loading capacities that enable the direct delivery of nucleic acids,mRNA,or protein molecules into cells.This bypasses the need for DNA transcription and processing,which significantly enhances therapeutic efficiency.Nevertheless,the immunogenic potential and accumulation toxicity associated with non-viral particulate systems necessitates continued optimization to reduce adverse effects in vivo.This review explores the various delivery systems for retinal therapies and retinal nerve regeneration,and details the characteristics,advantages,limitations,and clinical applications of each vector type.By systematically outlining these factors,our goal is to guide the selection of the optimal delivery tool for a specific retinal disease,which will enhance treatment efficacy and improve patient outcomes while paving the way for more effective and targeted therapeutic interventions.展开更多
Diabetic retinopathy is a prominent cause of blindness in adults,with early retinal ganglion cell loss contributing to visual dysfunction or blindness.In the brain,defects inγ-aminobutyric acid synaptic transmission ...Diabetic retinopathy is a prominent cause of blindness in adults,with early retinal ganglion cell loss contributing to visual dysfunction or blindness.In the brain,defects inγ-aminobutyric acid synaptic transmission are associated with pathophysiological and neurodegenerative disorders,whereas glucagon-like peptide-1 has demonstrated neuroprotective effects.However,it is not yet clear whether diabetes causes alterations in inhibitory input to retinal ganglion cells and whether and how glucagon-like peptide-1 protects against neurodegeneration in the diabetic retina through regulating inhibitory synaptic transmission to retinal ganglion cells.In the present study,we used the patch-clamp technique to recordγ-aminobutyric acid subtype A receptor-mediated miniature inhibitory postsynaptic currents in retinal ganglion cells from streptozotocin-induced diabetes model rats.We found that early diabetes(4 weeks of hyperglycemia)decreased the frequency of GABAergic miniature inhibitory postsynaptic currents in retinal ganglion cells without altering their amplitude,suggesting a reduction in the spontaneous release ofγ-aminobutyric acid to retinal ganglion cells.Topical administration of glucagon-like peptide-1 eyedrops over a period of 2 weeks effectively countered the hyperglycemia-induced downregulation of GABAergic mIPSC frequency,subsequently enhancing the survival of retinal ganglion cells.Concurrently,the protective effects of glucagon-like peptide-1 on retinal ganglion cells in diabetic rats were eliminated by topical administration of exendin-9-39,a specific glucagon-like peptide-1 receptor antagonist,or SR95531,a specific antagonist of theγ-aminobutyric acid subtype A receptor.Furthermore,extracellular perfusion of glucagon-like peptide-1 was found to elevate the frequencies of GABAergic miniature inhibitory postsynaptic currents in both ON-and OFF-type retinal ganglion cells.This elevation was shown to be mediated by activation of the phosphatidylinositol-phospholipase C/inositol 1,4,5-trisphosphate receptor/Ca2+/protein kinase C signaling pathway downstream of glucagon-like peptide-1 receptor activation.Moreover,multielectrode array recordings revealed that glucagon-like peptide-1 functionally augmented the photoresponses of ON-type retinal ganglion cells.Optomotor response tests demonstrated that diabetic rats exhibited reductions in visual acuity and contrast sensitivity that were significantly ameliorated by topical administration of glucagon-like peptide-1.These results suggest that glucagon-like peptide-1 facilitates the release ofγ-aminobutyric acid onto retinal ganglion cells through the activation of glucagon-like peptide-1 receptor,leading to the de-excitation of retinal ganglion cell circuits and the inhibition of excitotoxic processes associated with diabetic retinopathy.Collectively,our findings indicate that theγ-aminobutyric acid system has potential as a therapeutic target for mitigating early-stage diabetic retinopathy.Furthermore,the topical administration of glucagon-like peptide-1 eyedrops represents a non-invasive and effective treatment approach for managing early-stage diabetic retinopathy.展开更多
基金supported by the Natural Science Foundation of Shaanxi Province(Key Program),No.2021JZ-60(to HZ)。
文摘The unfolded protein response is a cellular pathway activated to maintain proteostasis and prevent cell death when the endoplasmic reticulum is overwhelmed by unfolded proteins.However,if the unfolded protein response fails to restore endoplasmic reticulum homeostasis,it can trigger proinflammatory and pro-death signals,which are implicated in various malignancies and are currently being investigated for their role in retinal degenerative diseases.This paper reviews the role of the unfolded protein responsein addressing endoplasmic reticulumstress in retinal degenerative diseases.The accumulation of ubiquitylated misfolded proteins can lead to rapid destabilization of the proteome and cellular demise.Targeting endoplasmic reticulum stress to alleviate retinal pathologies involves multiple strategies,including the use of chemical chaperones such as 4-phenylbutyric acid and tauroursodeoxycholic acid,which enhance protein folding and reduce endoplasmic reticulum stress.Small molecule modulators that influence endoplasmic reticulum stress sensors,including those that increase the expression of the endoplasmic reticulum stress regulator X-box binding protein 1,are also potential therapeutic agents.Additionally,inhibitors of the RNAse activity of inositol-requiring transmembrane kinase/endoribonuclease 1,a key endoplasmic reticulum stress sensor,represent another class of drugs that could prevent the formation of toxic aggregates.The activation of nuclear receptors,such as PPAR and FXR,may also help mitigate ER stress.Furthermore,enhancing proteolysis through the induction of autophagy or the inhibition of deubiquitinating enzymes can assist in clearing misfolded proteins.Combination treatments that involve endoplasmicreticulum-stress-targeting drugs and gene therapies are also being explored.Despite these potential therapeutic strategies,significant challenges remain in targeting endoplasmic reticulum stress for the treatment of retinal degeneration,and further research is essential to elucidate the mechanisms underlying human retinal diseases and to develop effective,well-tolerated drugs.The use of existing drugs that target inositol-requiring transmembrane kinase/endoribonuclease 1 and X-box binding protein 1 has been associated with adverse side effects,which have hindered their clinical translation.Moreover,signaling pathways downstream of endoplasmic reticulum stress sensors can contribute to therapy resistance.Addressing these limitations is crucial for developing drugs that can be effectively used in treating retinal dystrophies.In conclusion,while the unfolded protein response is a promising therapeutic target in retinal degenerative diseases,additional research and development efforts are imperative to overcome the current limitations and improve patient outcomes.
基金supported by the National Key Research and Development Program of China,No.2022YFA1105502(to PG)the National Natural Science Foundation of China,Nos.82271123(to PG),32200618(to ZT)。
文摘Traumatic optic neuropathy is a form of optic neuropathy resulting from trauma.Its pathophysiological mechanisms involve primary and secondary injury phases,leading to progressive retinal ganglion cell loss and axonal degeneration.Contributing factors such as physical trauma,oxidative stress,neuroinflammation,and glial scar formation exacerbate disease progression and retinal ganglion cell death.Multiple forms of cell death—including apoptosis,pyroptosis,necroptosis,and ferroptosis—are involved at different disease stages.Although current treatments,such as corticosteroid therapy and surgical interventions,have limited efficacy,cell-based therapies have emerged as a promising approach that simultaneously promotes neuroprotection and retinal ganglion cell regeneration.This review summarizes recent advances in cell-based therapies for traumatic optic neuropathy.In the context of cell replacement therapy,retinal ganglion cell-like cells derived from embryonic stem cells and induced pluripotent stem cells—via chemical induction or direct reprogramming—have demonstrated the ability to integrate into the host retina and survive for weeks to months,potentially improving visual function.Mesenchymal stem cells derived from various sources,including bone marrow,umbilical cord,placenta,and adipose tissue,have been shown to enhance retinal ganglion cell survival,stimulate axonal regeneration,and support partial functional recovery.Additionally,neural stem/progenitor cells derived from human embryonic stem cells offer neuroprotective effects and function as“neuronal relays,”facilitating reconnection between damaged regions of the optic nerve and the visual pathway.Beyond direct cell transplantation,cell-derived products,such as extracellular vesicles and cell-extracted solutions,have demonstrated promising neuroprotective effects in traumatic optic neuropathy.Despite significant progress,several challenges remain,including limited integration of transplanted cells,suboptimal functional vision recovery,the need for precise timing and delivery methods,and an incomplete understanding of the role of the retinal microenvironment and glial cell activation in neuroprotection and neuroregeneration.Furthermore,studies with longer observation periods and deeper mechanistic insights into the therapeutic effects of cell-based therapies remain scarce.Two Phase I clinical trials have confirmed the safety and potential benefits of cell-based therapy for traumatic optic neuropathy,with reported improvements in visual acuity.However,further studies are needed to validate these findings and establish significant therapeutic outcomes.In conclusion,cell-based therapies hold great promise for treating traumatic optic neuropathy,but critical obstacles must be overcome to achieve functional optic nerve regeneration.Emerging bioengineering strategies,such as scaffold-based transplantation,may improve cell survival and axonal guidance.Successful clinical translation will require rigorous preclinical validation,standardized protocols,and the integration of advanced imaging techniques to optimize therapeutic efficacy.
基金supported by the National Key Research and Development Program of China,No.2019YFA0111200the National Natural Science Foundation of China,Nos.U23A20436,82371047+3 种基金Key Research Project in Shanxi Province,No.202302130501008Shanxi Provincial Science Fund for Distinguished Young Scholars,No.202103021221008Key Research and Development Program in Shanxi Province,No.202204051001023Shanxi Medical University Doctor’s Startup Fund Project,No.SD22028(all to YG)。
文摘Retinal ganglion cells are the bridging neurons between the eye and the central nervous system,transmitting visual signals to the brain.The injury and loss of retinal ganglion cells are the primary pathological changes in several retinal degenerative diseases,including glaucoma,ischemic optic neuropathy,diabetic neuropathy,and optic neuritis.In mammals,injured retinal ganglion cells lack regenerative capacity and undergo apoptotic cell death within a few days of injury.Additionally,these cells exhibit limited regenerative ability,ultimately contributing to vision impairment and potentially leading to blindness.Currently,the only effective clinical treatment for glaucoma is to prevent vision loss by lowering intraocular pressure through medications or surgery;however,this approach cannot halt the effect of retinal ganglion cell loss on visual function.This review comprehensively investigates the mechanisms underlying retinal ganglion cell degeneration in retinal degenerative diseases and further explores the current status and potential of cell replacement therapy for regenerating retinal ganglion cells.As our understanding of the complex processes involved in retinal ganglion cell degeneration deepens,we can explore new treatment strategies,such as cell transplantation,which may offer more effective ways to mitigate the effect of retinal degenerative diseases on vision.
基金supported by the National Natural Science Foundation of China,Nos.82271132(to YL),82101167(to BB)the Natural Science Foundation of Chongqing,Nos.CSTB2022NSCQ-MSX0020(to BB),cstc2019jcyj-msxmX0473(to FC).
文摘Our previous study demonstrated that combined transplantation of bone marrow mesenchymal stem cells and retinal progenitor cells in rats has therapeutic effects on retinal degeneration that are superior to transplantation of retinal progenitor cells alone.Bone marrow mesenchymal stem cells regulate and interact with various cells in the retinal microenvironment by secreting neurotrophic factors and extracellular vesicles.Small extracellular vesicles derived from bone marrow mesenchymal stem cells,which offer low immunogenicity,minimal tumorigenic risk,and ease of transportation,have been utilized in the treatment of various neurological diseases.These vesicles exhibit various activities,including anti-inflammatory actions,promotion of tissue repair,and immune regulation.Therefore,novel strategies using human retinal progenitor cells combined with bone marrow mesenchymal stem cell-derived small extracellular vesicles may represent an innovation in stem cell therapy for retinal degeneration.In this study,we developed such an approach utilizing retinal progenitor cells combined with bone marrow mesenchymal stem cell-derived small extracellular vesicles to treat retinal degeneration in Royal College of Surgeons rats,a genetic model of retinal degeneration.Our findings revealed that the combination of bone marrow mesenchymal stem cell-derived small extracellular vesicles and retinal progenitor cells significantly improved visual function in these rats.The addition of bone marrow mesenchymal stem cell-derived small extracellular vesicles as adjuvants to stem cell transplantation with retinal progenitor cells enhanced the survival,migration,and differentiation of the exogenous retinal progenitor cells.Concurrently,these small extracellular vesicles inhibited the activation of regional microglia,promoted the migration of transplanted retinal progenitor cells to the inner nuclear layer of the retina,and facilitated their differentiation into photoreceptors and bipolar cells.These findings suggest that bone marrow mesenchymal stem cell-derived small extracellular vesicles potentiate the therapeutic efficacy of retinal progenitor cells in retinal degeneration by promoting their survival and differentiation.
基金Hongguang Wu,Both authors contributed equally to this work and share first authorshipLing Dong,Both authors contributed equally to this work and share first authorship。
文摘The human retina,a complex and highly specialized structure,includes multiple cell types that work synergistically to generate and transmit visual signals.However,genetic predisposition or age-related degeneration can lead to retinal damage that severely impairs vision or causes blindness.Treatment options for retinal diseases are limited,and there is an urgent need for innovative therapeutic strategies.Cell and gene therapies are promising because of the efficacy of delivery systems that transport therapeutic genes to targeted retinal cells.Gene delivery systems hold great promise for treating retinal diseases by enabling the targeted delivery of therapeutic genes to affected cells or by converting endogenous cells into functional ones to facilitate nerve regeneration,potentially restoring vision.This review focuses on two principal categories of gene delivery vectors used in the treatment of retinal diseases:viral and non-viral systems.Viral vectors,including lentiviruses and adeno-associated viruses,exploit the innate ability of viruses to infiltrate cells,which is followed by the introduction of therapeutic genetic material into target cells for gene correction.Lentiviruses can accommodate exogenous genes up to 8 kb in length,but their mechanism of integration into the host genome presents insertion mutation risks.Conversely,adeno-associated viruses are safer,as they exist as episomes in the nucleus,yet their limited packaging capacity constrains their application to a narrower spectrum of diseases,which necessitates the exploration of alternative delivery methods.In parallel,progress has also occurred in the development of novel non-viral delivery systems,particularly those based on liposomal technology.Manipulation of the ratios of hydrophilic and hydrophobic molecules within liposomes and the development of new lipid formulations have led to the creation of advanced non-viral vectors.These innovative systems include solid lipid nanoparticles,polymer nanoparticles,dendrimers,polymeric micelles,and polymeric nanoparticles.Compared with their viral counterparts,non-viral delivery systems offer markedly enhanced loading capacities that enable the direct delivery of nucleic acids,mRNA,or protein molecules into cells.This bypasses the need for DNA transcription and processing,which significantly enhances therapeutic efficiency.Nevertheless,the immunogenic potential and accumulation toxicity associated with non-viral particulate systems necessitates continued optimization to reduce adverse effects in vivo.This review explores the various delivery systems for retinal therapies and retinal nerve regeneration,and details the characteristics,advantages,limitations,and clinical applications of each vector type.By systematically outlining these factors,our goal is to guide the selection of the optimal delivery tool for a specific retinal disease,which will enhance treatment efficacy and improve patient outcomes while paving the way for more effective and targeted therapeutic interventions.
基金supported by the National Natural Science Foundation of China,Nos.32070989(to YMZ),31872766(to YMZ),81790640(to XLY),and 82070993(to SJW)the grant from Sanming Project of Medicine in Shenzhen,No.SZSM202011015(to XLY)。
文摘Diabetic retinopathy is a prominent cause of blindness in adults,with early retinal ganglion cell loss contributing to visual dysfunction or blindness.In the brain,defects inγ-aminobutyric acid synaptic transmission are associated with pathophysiological and neurodegenerative disorders,whereas glucagon-like peptide-1 has demonstrated neuroprotective effects.However,it is not yet clear whether diabetes causes alterations in inhibitory input to retinal ganglion cells and whether and how glucagon-like peptide-1 protects against neurodegeneration in the diabetic retina through regulating inhibitory synaptic transmission to retinal ganglion cells.In the present study,we used the patch-clamp technique to recordγ-aminobutyric acid subtype A receptor-mediated miniature inhibitory postsynaptic currents in retinal ganglion cells from streptozotocin-induced diabetes model rats.We found that early diabetes(4 weeks of hyperglycemia)decreased the frequency of GABAergic miniature inhibitory postsynaptic currents in retinal ganglion cells without altering their amplitude,suggesting a reduction in the spontaneous release ofγ-aminobutyric acid to retinal ganglion cells.Topical administration of glucagon-like peptide-1 eyedrops over a period of 2 weeks effectively countered the hyperglycemia-induced downregulation of GABAergic mIPSC frequency,subsequently enhancing the survival of retinal ganglion cells.Concurrently,the protective effects of glucagon-like peptide-1 on retinal ganglion cells in diabetic rats were eliminated by topical administration of exendin-9-39,a specific glucagon-like peptide-1 receptor antagonist,or SR95531,a specific antagonist of theγ-aminobutyric acid subtype A receptor.Furthermore,extracellular perfusion of glucagon-like peptide-1 was found to elevate the frequencies of GABAergic miniature inhibitory postsynaptic currents in both ON-and OFF-type retinal ganglion cells.This elevation was shown to be mediated by activation of the phosphatidylinositol-phospholipase C/inositol 1,4,5-trisphosphate receptor/Ca2+/protein kinase C signaling pathway downstream of glucagon-like peptide-1 receptor activation.Moreover,multielectrode array recordings revealed that glucagon-like peptide-1 functionally augmented the photoresponses of ON-type retinal ganglion cells.Optomotor response tests demonstrated that diabetic rats exhibited reductions in visual acuity and contrast sensitivity that were significantly ameliorated by topical administration of glucagon-like peptide-1.These results suggest that glucagon-like peptide-1 facilitates the release ofγ-aminobutyric acid onto retinal ganglion cells through the activation of glucagon-like peptide-1 receptor,leading to the de-excitation of retinal ganglion cell circuits and the inhibition of excitotoxic processes associated with diabetic retinopathy.Collectively,our findings indicate that theγ-aminobutyric acid system has potential as a therapeutic target for mitigating early-stage diabetic retinopathy.Furthermore,the topical administration of glucagon-like peptide-1 eyedrops represents a non-invasive and effective treatment approach for managing early-stage diabetic retinopathy.
