Flexible Ureteroscopy with a Tip-Flexible Pressure-Controlling Ureteral Access Sheath for Renal Stones in Children.

INTRODUCTION: The aim of this study was to evaluate the safety and efficacy of flexible ureteroscopy using a tip-flexible pressure-controlling ureteral access sheath (TFPC-UAS) for renal stones in children. METHODS: Consecutive patients aged 5-18 years with renal stones of diameter 1-3 cm were enrolled between January 2022 and November 2023 at Ganzhou People's Hospital. The patients were treated with flexible ureteroscopy using the TFPC-UAS. The renal pelvic pressure (RPP) parameters were set as follows: control value at -10 mm Hg to 5 mm Hg, warning value at 20 mm Hg, and limit value at 30 mm Hg. The infusion flow rate was set to 100-120 mL/min. A holmium laser (276 µm) was used to fragment the stone at 2.0-2.5 J/pulse with a frequency of 20-30 pulses/s. The cases were analyzed for RPP, operative time, stone-free rate, and complications. RESULTS: A total of 21 consecutive patients were included. Two patients were switched to percutaneous nephrolithotomy owing to sheath placement failure. The RPP was -4.6 ± 2.1 mm Hg. The mean operative time was 56.5 ± 17.1 min. The postoperative hospitalization time was 1.5 ± 0.3 days. The stone-free rates at 1 day and 1 month after surgery were 81.0% and 85.7%, respectively. Residual stones in 2 patients were cleared after extracorporeal shockwave lithotripsy. Three cases of Clavien I complications and one case of Clavien II complications occurred. No major complications (Clavien grade III-V) were observed. CONCLUSIONS: Flexible ureteroscopy with a TFPC-UAS is safe and effective for renal stones in children.

Regulatory Mechanisms of Retinal Photoreceptors Development at Single Cell Resolution.

Photoreceptors are critical components of the retina and play a role in the first step of the conversion of light to electric signals. With the discovery of the intrinsically photosensitive retinal ganglion cells, which regulate non-image-forming visual processes, our knowledge of the photosensitive cell family in the retina has deepened. Photoreceptor development is regulated by specific genes and proteins and involves a series of molecular processes including DNA transcription, post-transcriptional modification, protein translation, and post-translational modification. Single-cell sequencing is a promising technology for the study of photoreceptor development. This review presents an overview of the types of human photoreceptors, summarizes recent discoveries in the regulatory mechanisms underlying their development at single-cell resolution, and outlines the prospects in this field.

The Role of Histone Acetyltransferases and Histone Deacetylases in Photoreceptor Differentiation and Degeneration.

Photoreceptors are critical components of the retina and play a role in the first step of the conversion of light to electrical signals. The differentiation and degeneration of photoreceptors are regulated by specific genes and proteins. With the development of epigenetic approaches, scientists have discovered that histone modifications, such as acetylation, methylation, ubiquitylation, and phosphorylation, may modulate the processes of photoreceptor differentiation and degeneration. Histone acetylation is regulated by two opposing classes of enzymes, namely, histone acetyltransferases (HATs) and histone deacetylases (HDACs), which add and remove acetyl groups to and from target histones, respectively, causing changes in transcriptional activity. Herein, we review the effects of HATs and HDACs on the differentiation and degeneration of photoreceptors and discuss the underlying mechanisms of these effects.

Combination of doxorubicin with harmine-loaded liposomes exerting synergistic antitumor efficacy.

CONTEXT: Long-circulation (PEGLip), pH-sensitive (PEOzLip), and active targeted liposomes (PEG-TATLip)-loading doxorubicin (DOX) and harmine (HM) were prepared. Their physicochemical properties and antitumor effect were investigated. OBJECTIVES: The aims of the present study were to evaluate synergistic antitumor efficacy. MATERIALS AND METHODS: Liposomes were prepared by using thin-film dispersion, active drug-loading and target post-insertion method. Subsequently physiochemical properties including particle size distribution, zeta potential, entrapment efficiency (EE), drug-loading content and in-vitro release were determined. Besides, the in vitro cytotoxicity of free drugs and drug-loaded liposomes was explored by using a Sulforhodamine-B Staining assay and the combination index values (CI Value) were calculated. Finally, the cellular uptake experiments by MCF-7cells were carried out via flow cytometry. RESULTS AND DISCUSSION: All liposomes enhanced the antitumor effect significantly compared to free drugs. Among liposomes, PEG-TATLip enhanced the antitumor effect significantly compared to others. DOX and HM had moderate synergism with CI Value 0.85 for free drugs, 0.81 for PEGLip, 0.72 for PEOzLip, and 0.84 for PEG-TATLip respectively when the weight ratio of two drugs was 1:2. Moreover, the similarity between DOX and HM such as physicochemical properties, in vitro release modes and in vitro uptake kinetics characteristics when they were in the same formulations proved it possible for them to be delivered together. CONCLUSION: Active targeting liposomes were the most effective delivery system as compared with pH-sensitive and long circulation liposomes. Additionally, DOX and HM could be co-delivered in liposomes and they could play moderate synergism effect in antitumor efficacy.

c-Kit⁺ cells isolated from human fetal retinas represent a new population of retinal progenitor cells.

Definitive surface markers for retinal progenitor cells (RPCs) are still lacking. Therefore, we sorted c-Kit(+) and stage-specific embryonic antigen-4(-) (SSEA4(-)) retinal cells for further biological characterization. RPCs were isolated from human fetal retinas (gestational age of 12-14 weeks). c-Kit(+)/SSEA4(-) RPCs were sorted by fluorescence-activated cell sorting, and their proliferation and differentiation capabilities were evaluated by using immunocytochemistry and flow cytometry. The effectiveness and safety were assessed following injection of c-Kit(+)/SSEA4(-) cells into the subretina of Royal College of Surgeons (RCS) rats. c-Kit(+) cells were found in the inner part of the fetal retina. Sorted c-Kit(+)/SSEA4(-) cells expressed retinal stem cell markers. Our results clearly demonstrate the proliferative potential of these cells. Moreover, c-Kit(+)/SSEA4(-) cells differentiated into retinal cells that expressed markers of photoreceptor cells, ganglion cells and glial cells. These cells survived for at least 3 months after transplantation into the host subretinal space. Teratomas were not observed in the c-Kit(+)/SSEA4(-)-cell group. Thus, c-Kit can be used as a surface marker for RPCs, and c-Kit(+)/SSEA4(-) RPCs exhibit the ability to self-renew and differentiate into retinal cells.

Integrating Topographic Measures to Explore the Protective Effects of Peonidin Against the N-Methyl-N-Nitrosourea Induced Photoreceptor Degeneration.

BACKGROUND/AIMS: The pathphysiological properties of N-Methyl -N -nitrosourea (MNU) induced photoreceptor degeneration are similar to the hereditary retinitis pigmentosa (RP). The present study sought to explore the beneficial effects of the peonidin, a common aglycone form of anthocyanin, on the MNU induced photoreceptor degeneration via topographic measurements. METHODS: The MNU administrated mouse received peonidin or vehicle injections, and then they were examined by electroretinography (ERG), multi electrode array (MEA), histological and immunohistochemistry studies. RESULTS: The protective effects of peonidin on the MNU administrated retinas were systematically verified and quantified by topographic measures. The peonidin treatment could protect the photoreceptor against the MNU toxicity both functionally and morphologicaly. The most sensitive zone to peonidin therapy was sorted out, indicating that different rescuing kinetics existed between the retinal hemispheres and retinal quadrants. Moreover, the hyperactive spontaneous firing response and the debilitated light induced response in MNU administrated retinas could be partially reversed by peonidin treatment. To our knowledge, this was the first study to explore the pharmacological effects of peonidin on the electrophysiological properties of inner visual signal pathways. CONCLUSION: The peonidin could ameliorate the MNU induced photoreceptors degeneration and rectify the abnormities in the inner visual signal pathways. Future refinements of the knowledge cast insights into the discovery of a novel treatment for human RP.

Use of Hydrogen as a Novel Therapeutic Strategy Against Photoreceptor Degeneration in Retinitis Pigmentosa Patients.

Retinitis pigmentosa (RP) is a heterogeneous group of inherited retinal dystrophies characterized by progressive photoreceptor apoptosis. Reactive oxygen species (ROS) have been recognized as critical initiators of the photoreceptor apoptosis in RP. Photoreceptor survival in RP mutants will not only require the inhibition of effectors of apoptotic machinery, but also the elimination of the initiating upstream signals, such as ROS. These cytotoxic ROS should be neutralized by the antioxidant defense system, otherwise they would interact with the macromolecules essential for photoreceptor survival. Hydrogen is a promising gaseous agent that has come to the forefront of therapeutic research over the last few years. It has been verified that hydrogen is capable of neutralizing the cytotoxic ROS selectively, rectifying abnormities in the apoptotic cascades, and attenuating the related inflammatory response. Hydrogen is so mild that it does not disturb the metabolic oxidation-reduction reactions or disrupt the physiologic ROS involved in cell signaling. Based on these findings, we hypothesize that hydrogen might be an effective therapeutic agent to slow or prevent photoreceptor degeneration in RP retinas. It is a logical step to test hydrogen for therapeutic use in multiple RP animal models, and ultimately in human RP patients.

The neurotoxic effects of N-methyl-N-nitrosourea on the electrophysiological property and visual signal transmission of rat's retina.

The neurotoxic effects of N-methyl-N-nitrosourea (MNU) on the inner retinal neurons and related visual signal circuits have not been described in any animal models or human, despite ample morphological evidences about the MNU induced photoreceptor (PR) degeneration. With the helping of MEA (multielectrode array) recording system, we gained the opportunity to systemically explore the neural activities and visual signal pathways of MNU administrated rats. Our MEA research identified remarkable alterations in the electrophysiological properties and firstly provided instructive information about the neurotoxicity of MNU that affects the signal transmission in the inner retina. Moreover, the spatial electrophysiological functions of retina were monitored and found that the focal PRs had different vulnerabilities to the MNU. The MNU-induced PR dysfunction exhibited a distinct spatial- and time-dependent progression. In contrast, the spiking activities of both central and peripheral RGCs altered synchronously in response to the MNU administration. Pharmacological tests suggested that gap junctions played a pivotal role in this homogeneous response of RGCs. SNR analysis of MNU treated retina suggested that the signaling efficiency and fidelity of inner retinal circuits have been ruined by this toxicant, although the microstructure of the inner retina seemed relatively consolidated. The present study provided an appropriate example of MEA investigations on the toxicant induced pathological models and the effects of the pharmacological compounds on neuron activities. The positional MEA information would enrich our knowledge about the pathology of MNU induced RP models, and eventually be instrumental for elucidating the underlying mechanism of human RP.

The Spalt family transcription factor Sall3 regulates the development of cone photoreceptors and retinal horizontal interneurons.

The mammalian retina is a tractable model system for analyzing transcriptional networks that guide neural development. Spalt family zinc-finger transcription factors play a crucial role in photoreceptor specification in Drosophila, but their role in mammalian retinal development has not been investigated. In this study, we show that that the spalt homolog Sall3 is prominently expressed in developing cone photoreceptors and horizontal interneurons of the mouse retina and in a subset of cone bipolar cells. We find that Sall3 is both necessary and sufficient to activate the expression of multiple cone-specific genes, and that Sall3 protein is selectively bound to the promoter regions of these genes. Notably, Sall3 shows more prominent expression in short wavelength-sensitive cones than in medium wavelength-sensitive cones, and that Sall3 selectively activates expression of the short but not the medium wavelength-sensitive cone opsin gene. We further observe that Sall3 regulates the differentiation of horizontal interneurons, which form direct synaptic contacts with cone photoreceptors. Loss of function of Sall3 eliminates expression of the horizontal cell-specific transcription factor Lhx1, resulting in a radial displacement of horizontal cells that partially phenocopies the loss of function of Lhx1. These findings not only demonstrate that Spalt family transcription factors play a conserved role in regulating photoreceptor development in insects and mammals, but also identify Sall3 as a factor that regulates terminal differentiation of both cone photoreceptors and their postsynaptic partners.

Active opsin loci adopt intrachromosomal loops that depend on the photoreceptor transcription factor network.

Rod and cone opsin genes are expressed in a mutually exclusive manner in their respective photoreceptor subtypes in the mammalian retina. Previous transgenic mouse studies showed that functional interactions between the distal enhancer and proximal promoter of rhodopsin and long/medium-wavelength (L/M) opsin genes are essential for regulating their cell-type-specific transcription. We have used chromosomal conformation capture assays in mouse retinas to investigate the molecular mechanism responsible for this interaction. Here we show that each opsin gene forms intrachromosomal loops in the appropriate photoreceptor subtype, while maintaining a linear configuration in other cell types where it is silent. The enhancer forms physical contacts not only with the promoter but also with the coding regions of each opsin locus. ChIP assays showed that cell-type-specific target binding by three key photoreceptor transcription factors-cone--rod homeobox (CRX), neural retina leucine zipper (NRL), and nuclear receptor subfamily 2, group E, member 3 (NR2E3)--is required for the appropriate local chromosomal organization and transcription of rod and cone opsins. Similar correlations between chromosomal loops and active transcription of opsin genes were also observed in human photoreceptors. Furthermore, quantitative chromosomal conformation capture on human retinas from two male donors showed that the L/M enhancer locus control region (LCR) loops with either the L or M promoter in a near 3:1 ratio, supporting distance-dependent competition between L and M for LCR. Altogether, our results suggest that the photoreceptor transcription factor network cooperatively regulates the chromosomal organization of target genes to precisely control photoreceptor subtype-specific gene expression.

[Accuracy of immersion B-scan ultrasound biometry in high myopic patients with cataract].

OBJECTIVE: To compare the accuracy of axial length measurement with three methods, that is, immersion B-scan, contact A-scan, and IOLMaster in high myopia with cataract. METHODS: To analyze the data of the 40 patients (66 eyes), who were all high myopia with cataract and accepted the phacoemulsification and fold-able lens implantation surgery in our hospital from Jan 2012 to May 2012. The measurement of axial length was performed respectively in 66 eyes by immersion B-scan, contact A-scan and IOLMaster. Keratometric power was measured preoperatively by IOLMaster. The IOL power calculation was carried out according to SRK/T formula in the basis of IOLMaster. Their refraction outcome was follow-up three months after operation. RESULTS: The axial length was (27.91 ± 1.96) mm, (27.71 ± 2.15) mm, (27.88 ± 2.04) mm respectively by immersion B-scan, A-scan and IOLMaster. There was no significant difference between immersion B-scan and IOLMaster method (t = 0.726, P = 0.473). But the axial length measured by contact A-scan was shorter than that tested by immersion B-scan(t = 2.223, P = 0.003) and IOL Master (t = 2.614, P = 0.014) significantly. There was significant difference between immersion B-scan and contact A-Scan method in those patients whose mean absolute refractive error (MARE) was within ± 0.50 Diopter three months after operation (χ(2) = 5.67, P < 0.05) , while there was no significant difference between immersion B-scan and IOLMaster measurement (χ(2) = 0.06, P > 0.05). The same situation happened in those patients whose MARE was within ± 1.00 Diopter. That means, there was significant difference between immersion B-scan measurement and contact A-scan measurement (χ(2) = 4.19, P < 0.05) , while there was no significant difference between immersion B-scan and IOLMaster measurement(χ(2) = 0.36, P > 0.05). CONCLUSIONS: The immersion B-Scan measurement is better than A-scan, and it is as accurate as the IOL Master measurement, which is another good choice for the axial length measuring in high myopia with cataract cases.

Ferroptosis in the ageing retina: A malevolent fire of diabetic retinopathy.

Ageing retina is prone to ferroptosis due to the iron accumulation and impaired efficiency of intracellular antioxidant defense system. Ferroptosis acts as a cell death modality that is characterized by the iron-dependent accumulation of lipid peroxidation. Ferroptosis is distinctively different from other types of regulated cell death (RCD) at the morphological, biochemical, and genetic levels. Diabetic retinopathy (DR) is a common microvascular complication of diabetes. Its prevalence and severity increase progressively with age. Recent reports have shown that ferroptosis is implicated in the pathophysiology of DR. Under hyperglycemia condition, the endothelial cell and retinal pigment epithelium (RPE) cell will undergo ferroptosis, which contributes to the increased vascular permeability and the disrupted blood retinal barrier (BRB). The underlying etiology of DR can be attributed to the impaired BRB integrity and subsequent damages of the neurovascular units. In the absence of timely intervention, the compromised BRB can ultimately cause profound visual impairments. In particular, the ageing retina is vulnerable to ferroptosis, and hyperglycemia will accelerate the progression of this pathological process. In this article, we discuss the contributory role of ferroptosis in DR pathogenesis, and summarize recent therapeutic trials that targeting the ferroptosis. Further study on the ferroptosis mediated damage would enrich our knowledge of DR pathology, and promote the development of clinical treatment for this degenerative retinopathy.

Identification of a signature of histone modifiers in kidney renal clear cell carcinoma.

Kidney renal clear cell carcinoma (KIRC) is a cancer that is closely associated with epigenetic alterations, and histone modifiers (HMs) are closely related to epigenetic regulation. Therefore, this study aimed to comprehensively explore the function and prognostic value of HMs-based signature in KIRC. HMs were first obtained from top journal. Then, the mRNA expression profiles and clinical information in KIRC samples were downloaded from The Cancer Genome Atlas (TCGA) database and Gene Expression Omnibus (GEO) datasets. Cox regression analysis and least absolute shrinkage and selection operator (Lasso) analysis were implemented to find prognosis-related HMs and construct a risk model related to the prognosis in KIRC. Kaplan-Meier analysis was used to determine prognostic differences between high- and low-risk groups. Immune infiltration and drug sensitivity analysis were also performed between high- and low-risk groups. Eventually, 8 HMs were successfully identified for the construction of a risk model in KIRC. The results of the correlation analysis between risk signature and the prognosis showed HMs-based signature has good prognostic value in KIRC. Results of immune analysis of risk models showed there were significant differences in the level of immune cell infiltration and expression of immune checkpoints between high- and low-risk groups. The results of the drug sensitivity analysis showed that the high-risk group was more sensitive to several chemotherapeutic agents such as Sunitinib, Tipifarnib, Nilotinib and Bosutinib than the low-risk group. In conclusion, we successfully constructed HMs-based prognostic signature that can predict the prognosis of KIRC.

CX3CL1/CX3CR1 Signaling Mediated Neuroglia Activation Is Implicated in the Retinal Degeneration: A Potential Therapeutic Target to Prevent Photoreceptor Death.

Purpose: Retinal degeneration (RD) is a large cluster of retinopathies that is characterized by the progressive photoreceptor death and visual impairments. CX3CL1/CX3CR1 signaling has been documented to mediate the microglia activation and gliosis reaction during neurodegeneration. We intend to verify whether the CX3CL1/CX3CR1 signaling is involved in the RD pathology. Methods: A pharmacologically induced RD mice model was established. AZD8797, a CX3CR1 antagonist, was injected into the vitreous cavity of an RD model to modulate the neuroglia activation. Then, the experimental animals were subjected to functional, morphological, and behavioral analysis. Results: The CX3CL1/CX3CR1 signaling mediated neuroglia activation was implicated in the photoreceptor demise of an RD model. Intravitreal injection of AZD8797 preserved the retinal structure and enhanced the photoreceptor survival through inhibiting the CX3CL1/CX3CR1 expressions. Fundus photography showed that the distribution of retinal vessel was clear, and the severity of lesions was alleviated by AZD8797. In particular, these morphological benefits could be translated into remarkable functional improvements, as evidenced by the behavioral test and electroretinogram (mf-ERG) examination. A mechanism study showed that AZD8797 mitigated the microglia activation and migration in the degenerative retinas. The Müller cell hyper-reaction and secondary gliosis response were also suppressed by AZD8797. Conclusions: The neuroinflammation is implicated in the photoreceptor loss of RD pathology. Targeting the CX3CL1/CX3CR1 signaling may serve as an effective therapeutic strategy. Future refinements of these findings may cast light into the discovery of new medications for RD.

The orphan nuclear hormone receptor ERRbeta controls rod photoreceptor survival.

Mutation of rod photoreceptor-enriched transcription factors is a major cause of inherited blindness. We identified the orphan nuclear hormone receptor estrogen-related receptor beta (ERRbeta) as selectively expressed in rod photoreceptors. Overexpression of ERRbeta induces expression of rod-specific genes in retinas of wild-type as well as Nrl(-/-) mice, which lack rod photoreceptors. Mutation of ERRbeta results in dysfunction and degeneration of rods, whereas inverse agonists of ERRbeta trigger rapid rod degeneration, which is rescued by constitutively active mutants of ERRbeta. ERRbeta coordinates expression of multiple genes that are rate-limiting regulators of ATP generation and consumption in photoreceptors. Furthermore, enhancing ERRbeta activity rescues photoreceptor defects that result from loss of the photoreceptor-specific transcription factor Crx. Our findings demonstrate that ERRbeta is a critical regulator of rod photoreceptor function and survival, and suggest that ERRbeta agonists may be useful in the treatment of certain retinal dystrophies.

[Mitochondrial 12S rRNA A1555G mutation associated with nonsyndromic hearing loss in twenty-five Han Chinese pedigrees].

Mitochondrial 12S rRNA A1555AG mutation is one of the important causes of aminoglycoside-induced and nonsyndromic deafness. We report here the clinical, genetic and molecular characterization of 25 Chinese families carrying the A1555G mutation.Clinical and genetic characterizations of these Chinese families exhibited a wide range of penetrance, severity and age-at-onset of hearing impairment. The average penetrances of deafness were 28.1% and 21.5%, respectively, when aminoglycoside-induced hearing loss was included or excluded. Furthermore, the average age-of-onset for deafness without aminoglycoside exposure ranged from 1 and 15 years old. Their mitochondrial genomes exhibited distinct sets of polymorphisms including 16 novel variants, belonging to ten Eastern Asian haplogroups A, B, D, F, G, M, N and R, respectively. Strikingly, these Chinese families carrying mitochondrial haplogroup B exhibited higher penetrance and expressivity of hearing loss. In addition, 7 known secondary mutations and 21 variants resided at the highly conservative residues may enhance the penetrace of hearing loss in these Chinese families. Moreover, the absence of mutation in GJB2 gene suggested that GJB2 may not be a modifier for the phenotypic expression of the A1555G mutation in these Chinese families. These observations suggested that mitochondrial haplotypes and other modifiers may modulate the variable penetrance and expressivity of deafness among these Chinese families.

The molecular mechanism of human stem cell-derived extracellular vesicles in retinal repair and regeneration.

Extracellular vesicles (EVs), including microvesicles (MVs) and exosomes, play a critical role in metabolic regulation and intracellular communication. Stem cell-derived EVs are considered to have the potential for regeneration, like stem cells, while simultaneously avoiding the risk of immune rejection or tumour formation. The therapeutic effect of stem cell-derived EVs has been proven in many diseases. However, the molecular mechanism of stem cell-derived EVs in retinal repair and regeneration has not been fully clarified. In this review, we described the biological characteristics of stem cell-derived EVs, summarized the current research on stem cell-derived EV treatment in retinal repair and regeneration, and discussed the potential and challenges of stem cell-derived EVs in translational medicine.

The role of epigenetic methylation/demethylation in the regulation of retinal photoreceptors.

Photoreceptors are integral and crucial for the retina, as they convert light into electrical signals. Epigenetics plays a vital role in determining the precise expression of genetic information in space and time during the development and maturation of photoreceptors, cell differentiation, degeneration, death, and various pathological processes. Epigenetic regulation has three main manifestations: histone modification, DNA methylation, and RNA-based mechanisms, where methylation is involved in two regulatory mechanisms-histone methylation and DNA methylation. DNA methylation is the most studied form of epigenetic modification, while histone methylation is a relatively stable regulatory mechanism. Evidence suggests that normal methylation regulation is essential for the growth and development of photoreceptors and the maintenance of their functions, while abnormal methylation can lead to many pathological forms of photoreceptors. However, the role of methylation/demethylation in regulating retinal photoreceptors remains unclear. Therefore, this study aims to review the role of methylation/demethylation in regulating photoreceptors in various physiological and pathological situations and discuss the underlying mechanisms involved. Given the critical role of epigenetic regulation in gene expression and cellular differentiation, investigating the specific molecular mechanisms underlying these processes in photoreceptors may provide valuable insights into the pathogenesis of retinal diseases. Moreover, understanding these mechanisms could lead to the development of novel therapies that target the epigenetic machinery, thereby promoting the maintenance of retinal function throughout an individual's lifespan.

Intravitreal Injection of ZYAN1 Restored Autophagy and Alleviated Oxidative Stress in Degenerating Retina via the HIF-1α/BNIP3 Pathway.

Mitochondrial autophagy plays a contributary role in the pathogenesis of retina degeneration (RD). ZYAN1 is a novel proline hydroxylase domain (PHD) inhibitor that can enhance the expression of hypoxia-inducible factor 1-alpha (HIF-1α). This study investigated whether ZYAN1 could alleviate progressive photoreceptor loss and oxidative damage in a pharmacologically induced RD model via the modulation of mitophagy. ZYAN1 was injected into the vitreous body of the RD model, and the retinal autophagy level was analyzed. The therapeutic effects of ZYAN1 were evaluated via a function examination, a morphological assay, in situ reactive oxygen species (ROS) detection, and an immunofluorescence assay. It was shown that the thickness of the outer nuclear layer (ONL) increased significantly, and visual function was efficiently preserved via ZYAN1 treatment. The mitochondria structure of photoreceptors was more complete in the ZYAN1-treated mice, and the number of autophagosomes also increased significantly. Membrane disc shedding and ROS overproduction were alleviated after ZYAN1 treatment, and the axonal cilia were more structurally intact. A Western blot analysis showed that the expression levels of the autophagy-related proteins LC3-B, Beclin-1, and ATG5 increased significantly after ZYAN1 treatment, while the expression of P62 was down-regulated. Moreover, the expression levels of HIF-1α and BNIP3 were up-regulated after ZYAN1 treatment. Therefore, an intravitreal injection of ZYAN1 can act as part of the pharmacologic strategy to modulate mitophagy and alleviate oxidative stress in RD. These findings enrich our knowledge of RD pathology and provide insights for the discovery of a therapeutic molecule.

Epigenetic mechanisms of Müller glial reprogramming mediating retinal regeneration.

Retinal degenerative diseases, characterized by retinal neuronal death and severe vision loss, affect millions of people worldwide. One of the most promising treatment methods for retinal degenerative diseases is to reprogram non-neuronal cells into stem or progenitor cells, which then have the potential to re-differentiate to replace the dead neurons, thereby promoting retinal regeneration. Müller glia are the major glial cell type and play an important regulatory role in retinal metabolism and retinal cell regeneration. Müller glia can serve as a source of neurogenic progenitor cells in organisms with the ability to regenerate the nervous system. Current evidence points toward the reprogramming process of Müller glia, involving changes in the expression of pluripotent factors and other key signaling molecules that may be regulated by epigenetic mechanisms. This review summarizes recent knowledge of epigenetic modifications involved in the reprogramming process of Müller glia and the subsequent changes to gene expression and the outcomes. In living organisms, epigenetic mechanisms mainly include DNA methylation, histone modification, and microRNA-mediated miRNA degradation, all of which play a crucial role in the reprogramming process of Müller glia. The information presented in this review will improve the understanding of the mechanisms underlying the Müller glial reprogramming process and provide a research basis for the development of Müller glial reprogramming therapy for retinal degenerative diseases.