Enhanced innate responses in microglia derived from retinoblastoma patient-specific iPSCs.

RB1 deficiency leads to retinoblastoma (Rb), the most prevalent intraocular malignancy. Tumor-associated macrophages (TAMs) are related to local inflammation disorder, particularly by increasing cytokines and immune escape. Microglia, the unique resident macrophages for retinal homeostasis, are the most important immune cells of Rb. However, whether RB1 deficiency affects microglial function remain unknown. In this study, microglia were successfully differentiated from Rb patient- derived human induced pluripotent stem cells (hiPSCs) and human embryonic stem cells (hESCs), and then we investigated the function of RB1 in microglia by live imaging phagocytosis assay, immunofluorescence, RNA-seq, qRT-PCR, ELISA and retina organoids/microglia co-culturing. RB1 was abundantly expressed in microglia and predominantly located in the nucleus. We then examined the phagocytosis ability and secretion function of iMGs in vitro. We found that RB1 deficiency did not affect the expression of microglia-specific markers or the phagocytic abilities of these cells by live-imaging. Upon LPS stimulation, RB1-deficient microglia displayed enhanced innate immune responses, as evidenced by activated MAPK signaling pathway and elevated expression of IL-6 and TNF-α at both mRNA and protein levels, compared to wildtype microglia. Furthermore, retinal structure disruption was observed when retinal organoids were co-cultured with RB1-deficient microglia, highlighting the potential contribution of microglia to Rb development and potential therapeutic strategies for retinoblastoma.

Foveal Microstructure and Visual Outcomes after Pars Plana Vitrectomy in Patients with Different Types of Epiretinal Membrane Foveoschisis.

INTRODUCTION: The aim of this study was to evaluate the clinical characteristics and surgical outcomes of the epiretinal membrane foveoschisis (ERM-FS) with different morphological types. METHODS: This retrospective observational study reviewed 44 consecutive ERM-FS patients who underwent ERM surgery. According to the optical coherence tomography images, ERM-FS was classified into three groups: group A, FS crossed the fovea with the foveola elevated; group B, FS located at the foveal edges with a near-normal central foveal point thickness; and group C, FS with undermined foveal edges with a near-normal central foveal point thickness. RESULTS: There were 10 eyes in group A, 20 eyes in group B, and 14 eyes in group C. Preoperatively, eyes in group A had the best best-corrected visual acuity (BCVA), the thickest central foveal point thickness, and the highest ellipsoid zone (EZ) intact rate among the three groups. After surgery, a resolution of foveoschisis was observed in 40.0%, 45.0%, and 50.0% of the eyes in group A, group B, and group C (p = 0.928), respectively. BCVA was significantly improved postoperatively. Although there was no significant difference in BCVA among the three groups at 1 month postoperatively, BCVA of group A was the best at 4 and 10 months. Correlation analysis indicated that the type of ERM-FS, baseline BCVA, central foveal point thickness, and postoperative EZ continuity (all p < 0.05) were important factors for the final BCVA. CONCLUSIONS: The damage to the retinal structure and visual function was milder in group A ERM-FS. Our study emphasized the necessity of OCT-based subtyping in patients with ERM-FS.

RNA fusion in human retinal development.

Chimeric RNAs have been found in both cancerous and healthy human cells. They have regulatory effects on human stem/progenitor cell differentiation, stemness maintenance, and central nervous system development. However, whether they are present in human retinal cells and their physiological functions in the retinal development remain unknown. Based on the human embryonic stem cell-derived retinal organoids (ROs) spanning from days 0 to 120, we present the expression atlas of chimeric RNAs throughout the developing ROs. We confirmed the existence of some common chimeric RNAs and also discovered many novel chimeric RNAs during retinal development. We focused on CTNNBIP1-CLSTN1 (CTCL) whose downregulation caused precocious neuronal differentiation and a marked reduction of neural progenitors in human cerebral organoids. CTCL is universally present in human retinas, ROs, and retinal cell lines, and its loss-of-function biases the progenitor cells toward retinal pigment epithelial cell fate at the expense of retinal cells. Together, this work provides a landscape of chimeric RNAs and reveals evidence for their critical role in human retinal development.

The Evolution and Visual Prognosis of Glial Proliferation with Different Grades after Macular Hole Surgery: An Optical Coherence Tomography-Based Study.

INTRODUCTION: The glial proliferation after macular hole (MH) surgery was divided into two types previously: those replacing the entire intraretinal layer and those involving only the inner foveal layers. The evolution and prognosis of the former type were elaborated on in previous studies, but the latter one has received limited attention. Therefore, this study aims to investigate the evolution of glial proliferation with varying grades after MH surgery and its effects on foveal microstructure and best-corrected visual acuity (BCVA). METHODS: In this retrospective research, we reviewed 202 eyes from 196 consecutive patients who underwent a successful idiopathic MHs repair. Based on optical coherence tomography images, glial proliferation was classified into three types: A-type, which replaced the entire intraretinal layer; B-type, located at the level of and above the external limiting membrane (ELM); and C-type, situated above the ELM. RESULTS: Of the 67 eyes that attended the 1-, 4-, and 10-month follow-up, A-type, B-type, C-type, and no glial proliferation were identified in 27 (40.3%), 17 (25.4%), 20 (29.8%), and 3 eyes (4.5%), respectively, at 1 month. Within 10 months, the prevalence of A-type glial proliferation significantly decreased (p < 0.001), but the changes in B-type (p = 0.261), C-type (p = 0.151), and no glial proliferation (p = 0.492) were not significant. In 32 of the 67 eyes, the grade of glial proliferation gradually improved, with A-type transforming into B- or C-type in 19 of 27 eyes (70.4%), B-type into C-type or no glial proliferation in 11 out of 17 eyes (64.7%), and C-type gradually disappearing in 2 out of 20 eyes (10.0%). Among the eyes that attended at least one follow-up (1 M, 202 eyes; 4 M, 161 eyes; 10 M, 97 eyes), those with A-type glial proliferation showed the most defective outer retinal layers, worst BCVA, and thinnest central fovea compared with the other two types at all follow-up time points (p < 0.001). Eyes with C-type glial proliferation exhibited significantly better photoreceptor layer status and BCVA compared with those with B-type glial proliferation. A-type glial proliferation at 1 month, which showed significant association with BCVA at 10 months, could be accurately predicted by the minimum linear diameter with a cut-off >547.5 µm (p < 0.001). CONCLUSION: Within 10 months, A-type glial proliferation substantially resolves but the prevalence of B- and C-type remains unchanged. B-type glial proliferation hinders the restoration of photoreceptors and impairs visual recovery despite being located within the inner retina.

REG1A protects retinal photoreceptors from blue light damage.

With the increased use of artificial light and the prolonged use of optoelectronic products, light damage (LD) to the human retina has been identified as a global vision-threatening problem. While there is evidence of a significant correlation between light-induced retinal damage and age-related vision impairment in age-related macular degeneration, it is unclear how light-induced retinal degeneration manifests itself and whether there are agents capable of preventing the development of LD in the retina. This study investigated a mechanism by which blue light leads to photoreceptor death. By observing blue light exposure in retinal organoids and photoreceptor cells, we concluded that there could be significant apoptosis of the photoreceptors. We demonstrate that regenerating islet-derived 1 alpha (REG1A) prevents photoreceptors from undergoing this LD-induced apoptosis by increasing expression of the anti-apoptotic gene Bcl2 and downregulating expression of the pro-apoptotic gene Bax, resulting in reduced mitochondrial damage and improved aerobic capacity in photoreceptor cells. For the first time, REG1A has been shown to restore mitochondrial function and cell apoptosis after LD-induced damage, suggesting its potential application in the prevention and treatment of retinal vision loss.

Generation of the induced pluripotent stem cell line SFMUi001-A from a patient with usher syndrome type 2 caused by biallelic variants in the USH2A gene.

Biallelic variants in the USH2A gene cause Usher syndrome type 2 (USH2), in which patients' symptoms are progressive night blindness, reduced visual field, decreased central vision and sensorineural hearing impairment. There is currently no effective drug for USH2. In this study, we isolated peripheral blood mononuclear cells from a patient with USH2. The pluripotency of induced cells was verified by the presence of cell surface markers, the expression of pluripotent genes, and the formation of teratomas. The generation of this induced pluripotent stem cell line provides an effective way to study USH2, such as disease modeling and drug screening. Usher syndrome type 2 (USH2) is a genetic disease mainly caused by biallelic variants in the USH2A gene. Patients usually present with progressive night blindness, reduced visual field, and then reduced central vision. Patients with USH2 also have sensorineural hearing impairment. There is currently no effective treatment for USH2, and the pathogenesis is still unclear. Therefore, it is of great significance to study the pathogenic mechanism of USH2A gene variants for the study of therapeutic targets. In this study, we obtained induced pluripotent stem cell (iPSC) line containing USH2A gene variants. We isolated mononuclear cells from the peripheral blood of patient and established iPSCs by reprogramming with nonintegrating vectors. We then confirmed the pluripotency of our generated iPSCs through the detection of multiple cell surface markers, the expression of pluripotency-related genes, and the ability to form teratomas with three germ layer structures in vivo. The generation of this cell line will facilitate research on USH2 disease and will play a role that cannot be underestimated in future organoid generation, drug screening, and research on drug targets as well as mechanisms.

Immunomodulatory properties of mesenchymal stem cells: A potential therapeutic strategy for allergic rhinitis.

Allergic rhinitis is a highly prevalent chronic inflammatory disorder of the nasal mucosa that poses a significant burden on patients' health and quality of life. Current therapies for allergic rhinitis are unable to reinstate immune homeostasis or are restricted by specific allergens. Potential therapeutic strategies for allergic rhinitis are urgently needed. Mesenchymal stem cells (MSCs) are immune-privileged, have strong immunomodulatory effects, and can be easily isolated from various sources. Thus, MSC-based therapies demonstrate potential for treating inflammatory diseases. Recently, numerous studies have investigated the therapeutic effects of MSCs in animal models of allergic rhinitis. Here, we review the immunomodulatory effects and mechanisms of MSCs on allergic airway inflammation, especially allergic rhinitis, highlight the recent research regarding MSCs in the modulation of immune cells, and discuss the clinical potential of MSC-based therapy for allergic rhinitis.

SLAMF7/STAT6 Pathway Inhibits Innate Immune Response in Late-Stage Human Acanthamoeba Keratitis: A Comparative Transcriptome Analysis.

Acanthamoeba keratitis (AK) is a blinding corneal infection caused by the protozoan Acanthamoeba. The long-term course of AK suggests the host immunity could not kill Acanthamoeba rapidly. The immune status is still unclear in the late stage of AK. The comparative transcriptome analysis was made based on the bulk RNA sequencing of cornea tissues from AK patients and donors. Differentially expressed genes and enriched signaling pathways were calculated. CIBERSORT algorithm was used for immune infiltration analysis of cornea tissue between AK and normal controls. A total of 2668 differentially expressed genes, including 1477 upregulated genes and 1191 downregulated genes, were detected. Gene Ontology analysis revealed that the pathways were significantly enriched in leukocyte migration, regulation of T-cell activation, the external side of plasma membrane, collagen-containing extracellular matrix, immune receptor activity, and cytokine binding. The Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that the pathways were significantly enriched in the cytokine-cytokine receptor interaction, hematopoietic cell lineage, and Staphylococcus aureus infection pathway. The immune infiltration profiles varied little between AK and normal controls. Compared with normal tissue, cornea tissue of AK contained a higher proportion of M0 macrophages and CD8 T cells, while resting memory CD4 T cells contributed to a relatively lower portion (p < 0.05). Finally, the expression levels of cell markers and SLAMF7/STAT6 pathway were confirmed by histopathology examinations, RT-qPCR, and Western blot.

Microglial hexokinase 2 deficiency increases ATP generation through lipid metabolism leading to ß-amyloid clearance.

Microglial cells consume adenosine triphosphate (ATP) during phagocytosis to clear neurotoxic ß-amyloid in Alzheimer's disease (AD). However, the contribution of energy metabolism to microglial function in AD remains unclear. Here, we demonstrate that hexokinase 2 (HK2) is elevated in microglia from an AD mouse model (5xFAD) and AD patients. Genetic deletion or pharmacological inhibition of HK2 significantly promotes microglial phagocytosis, lowers the amyloid plaque burden and attenuates cognitive impairment in male AD mice. Notably, the ATP level is dramatically increased in HK2-deficient or inactive microglia, which can be attributed to a marked upregulation in lipoprotein lipase (LPL) expression and subsequent increase in lipid metabolism. We further show that two downstream metabolites of HK2, glucose-6-phosphate and fructose-6-phosphate, can reverse HK2-deficiency-induced upregulation of LPL, thus supporting ATP production and microglial phagocytosis. Our findings uncover a crucial role for HK2 in phagocytosis through regulation of microglial energy metabolism, suggesting a potential therapeutic strategy for AD by targeting HK2.

Reconstruct Human Retinoblastoma In Vitro.

Human RB is pediatric cancer, which is lethal if no treatment is administered. As RB originates from cone precursors, which is relatively rare in rodent models, meanwhile regarding the interspecies differences between humans and rodents, a disease model derived from humans is more beneficial for uncovering the mechanisms of human RB and seeking the targets of therapy. Herein, the protocol describes the generation of two gene-edited hESC lines with a biallelic RB1 point mutation (RB1Mut/Mut) and an RB1 knockout mutation (RB1-/-), respectively. During the process of retinal development, the formation of RB is observed. The RB cell lines are also established by segregating from the RB organoids. Altogether, by differentiating the gene-edited hESC lines into the retinal organoids using a 2D and 3D combined differentiation protocol, we have successfully reconstructed the human RB in a dish and identified its cone-precursor origin. It would provide a helpful disease model for observing the retinoblastoma genesis, proliferation, and growth as well as further developing novel therapeutic agents.

Effects and Prognosis of Cataract Surgery in Patients with Retinitis Pigmentosa.

INTRODUCTION: Cataract extraction could improve visual acuity (VA) for patients with retinitis pigmentosa (RP), while the surgery may increase photoreceptor degeneration through light damage. In this study, we conducted a systematic review and meta-analysis to investigate the effectiveness and prediction of VA after cataract surgery in patients with RP. METHODS: We comprehensively extracted data from literature of available studies with quality control processing. Improvement of VA before and after cataract surgery of different durations of follow-up and different structural integrity of the preoperative macular ellipsoid zone (EZ) in patients with RP were compared. VA was measured by the logarithm of the minimum angle of resolution (logMAR). RESULTS: Sixteen studies were subjected to analysis. Postoperative VA was significantly improved versus preoperative, with a mean difference (MD) of 0.57 [95% confidence interval (CI) 0.45, 0.69], and a fixed-effect model was applied during follow-up durations of 1 day to 1 month (I2 = 0%). Similarly, for follow-up durations of 1-3 months, 3-6 months, and 6-12 months, postoperative VAs were all better than preoperative values, with MDs of 0.36 (95% CI 0.31, 0.41), 0.35 (95% CI 0.23, 0.46), and 0.22 (95% CI 0.14, 0.30) (I2 < 50%). For follow-up duration of 1-5 years, the random-effect model was applied for higher heterogeneity (I2 = 81%), with an MD of 0.26 (95% CI 0.09, 0.43). There was no significant difference in the improvement of the EZ-invisible group, with an MD of 0.27 (95% CI - 0.17, 0.70) (I2 = 82%). There were significant differences between EZ-abnormal and EZ-normal groups in preoperative and postoperative VA, with MDs of 0.56 (95% CI 0.27, 0.85) and 0.46 (95% CI 0.27, 0.65) (I2 > 50%). CONCLUSIONS: Cataract surgery could improve VA for patients with RP during long-term follow-up, and the surgery is not recommended for patients with invisible preoperative macular EZ. However, further studies are required to address the problem of excessive light exposure to the degenerated retina in patients with RP with the cataract removed. The study protocol was registered on the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42022340165).

Therapeutic Effects of Human Pluripotent Stem Cell-Derived Mesenchymal Stem Cells on a Murine Model of Acute Type-2-Dominated Airway Inflammation.

Allergic rhinitis and allergic asthma are the most common type-2 inflammatory diseases, which are hardly curable and cause heavy burden to general well-being. Mesenchymal stem cells (MSCs) are multipotent nonhematopoietic cells with potential immunomodulatory effects that have been showning to have a therapeutic effect on allergic diseases. Here, we investigated the effects of human induced pluripotent stem cell (iPSC)-derived MSCs on airway hyperresponsiveness and acute type-2-dominated inflammation throughout the upper and lower airways. In this study, human MSCs, MSC cell culture supernatant, and culture medium (control) was injected into the acute airway inflammatory model via the tail vein. Mouse behavioristics were recorded immediately and mouse lung function was measured 24 hours after the last ovalbumin (OVA) challenge. Histological staining, Luminex, Elisa and flow cytometry were employed to evaluate the effects on the production of total/OVA-specific IgG1 and IgE, cytokines expression in lung tissues, and inflammatory cells infiltration in the lung and spleen of the experimental mice. Expressions of eotaxin, IL-4, IL-5, IL-13, IL-33 in nasal and lung lavage were evaluated by Luminex and Elisa. We found that for this acute inflammatory mouse model, human MSC transplantation significantly mitigated the decreased motoring time and the increased lung function Rrs caused by OVA challenge. Serum OVA-IgG1, OVA-IgE, and eosinophil percentages in the splenocytes were significantly decreased. Injection of the MSC supernatant also showed the same trend, but not significantly changed. After treatment, IL-4 and IL-13 were significantly decreased in the lung tissue, and IL-5 and IL-13 were significantly decreased in lung lavage. In conclusion, both human MSC culture supernatant and cell transplantation could alleviate AHR and inflammation in acute inflammatory experimental animals, which demonstrated their potential for clinical therapeutics. Human iPSC-MSCs, MSC cell culture supernatant, or culture medium (control) was injected into the OVA-induced acute airway inflammatory model via the tail vein. Behavioral changes, AHR, serum OVA-specific IgG1 and IgE concentrations, and type-2 inflammations were alleviated.

CLEC3B is a novel causative gene for macular-retinal dystrophy.

PURPOSE: Macular degeneration is the leading cause of blindness worldwide. In this study, we aimed to define a new subtype of macular-retinal dystrophy and its genetic predisposition in 5 families. METHODS: Exome sequencing was performed to determine the putative disease-causing genes in patients with inherited macular disorders confirmed through comprehensive ophthalmic examinations. To validate its functional consequence, adeno-associated virus-mediated mutant gene was delivered into the murine retina, and both structural and functional tests were performed to investigate its pathological effects in vivo. RESULTS: In total, 5 multigenerational families diagnosed with autosomal dominant maculoretinopathy were found to carry a pathogenic variant in a new gene, CLEC3B, which encodes tetranectin, a plasminogen kringle-4 binding protein. Consistent with the disease phenotypes of patients, mice that received subretinal injections with the CLEC3B variant displayed multiple subretinal hyperreflective deposits, reduced retinal thickness, and decreased electroretinographic responses. Moreover, the optokinetic tracking response indicated that spatial frequency was significantly lower (P < .05), implying impaired visual function in these mice. CONCLUSION: We have presented a new subtype of macular-retinal dystrophy in 5 families as well as a new pathogenic gene, CLEC3B, providing new insights into maculoretinopathy etiology.

miR-182 targeting reprograms tumor-associated macrophages and limits breast cancer progression.

The protumor roles of alternatively activated (M2) tumor-associated macrophages (TAMs) have been well established, and macrophage reprogramming is an important therapeutic goal. However, the mechanisms of TAM polarization remain incompletely understood, and effective strategies for macrophage targeting are lacking. Here, we show that miR-182 in macrophages mediates tumor-induced M2 polarization and can be targeted for therapeutic macrophage reprogramming. Constitutive miR-182 knockout in host mice and conditional knockout in macrophages impair M2-like TAMs and breast tumor development. Targeted depletion of macrophages in mice blocks the effect of miR-182 deficiency in tumor progression while reconstitution of miR-182-expressing macrophages promotes tumor growth. Mechanistically, cancer cells induce miR-182 expression in macrophages by TGFß signaling, and miR-182 directly suppresses TLR4, leading to NFκb inactivation and M2 polarization of TAMs. Importantly, therapeutic delivery of antagomiR-182 with cationized mannan-modified extracellular vesicles effectively targets macrophages, leading to miR-182 inhibition, macrophage reprogramming, and tumor suppression in multiple breast cancer models of mice. Overall, our findings reveal a crucial TGFß/miR-182/TLR4 axis for TAM polarization and provide rationale for RNA-based therapeutics of TAM targeting in cancer.

Second hit impels oncogenesis of retinoblastoma in patient-induced pluripotent stem cell-derived retinal organoids: direct evidence for Knudson's theory.

Retinoblastoma (Rb) is a type of malignant tumor due to abnormal retinogenesis with biallelic mutations of the RB1 gene. Its pathogenesis has been proposed as a "two-mutation hypothesis" by Knudson since 1971; however, there remain some debates on disease onset sufficiency of the biallelic RB1 mutations. To obtain straightforward evidence for this hypothesis, we investigated whether two-hit mutations of the RB1 gene drive tumorigenesis in patient-induced pluripotent stem cell (hiPSC)-derived human retinal organoids (hROs) and whether single allelic mutation hiPSC-derived hROs exhibit molecular and cellular defects. We generated hiPSCs with a heterozygous germline mutation (RB1m1/ wt ) from a Rb patient. A second-allele RB1 gene mutation was knocked in to produce compound heterozygous mutations (RB1m1/m2 ) in the hiPSCs. These two hiPSC lines were independently developed into hROs through a stepwise differentiation. The hiPSC-RB1m1/m2 derived organoids demonstrated tumorigenesis in dishes, consistent with Rb profiles in spatiotemporal transcriptomes, in which developmentally photoreceptor fate-determining markers, CRX and OTX2, were highly expressed in hiPSC-RB1m1/m2 derived hROs. Additionally, ARR3+ maturing cone precursors were co-labeled with proliferative markers Ki67 or PCNA, in agreement with the consensus that human Rb is originated from maturing cone precursors. Finally, we demonstrated that retinal cells of hROs with monoallelic RB1 mutation were abnormal in molecular aspects due to its haploinsufficiency. In conclusion, this study provides straightforward supporting evidence in a way of reverse genetics for "two-hit hypothesis" in the Rb tumorigenesis and opens new avenues for development of early intervention and treatment of Rb.

Circular Rims2 Deficiency Causes Retinal Degeneration.

Circular RNAs (circRNAs) refer to a newly recognized family of non-coding RNA with single-stranded RNAs. Despite emerging evidence indicating that circRNAs are abundantly expressed in various tissues, especially in the brain and retina, the role of circRNAs in retinal function and diseases is still largely unknown. Circular Rims2 (circRims2) is highly expressed and conserved in both the human and mouse brains. However, little is known about the expression and function of circRims2 in the retina. In the current study, the high-throughput RNA-seq analysis reveals a high expression of circRims2 in the retina. In addition, it is found that circRims2 is mainly located in plexiform layers that contain synapses between retinal neurons. Knocking down circRims2 with short hairpin RNA through subretinal adeno-associated viral (AAV) delivery in the mice leads to the decrease of the thickness of the outer and inner segment (OS/IS) layers and outer nuclear layer (ONL), and cessation of scotopic and photopic electroretinogram responses. Furthermore, the current study finds that circRims2 deficiency evokes retinal inflammation and activates the tumor necrosis factor (TNF) signaling pathway. Therefore, circRims2 may play an important role in the maintenance of retinal structure and function, and circRims2 deficiency may lead to pathogenic changes in the retina.

Retinal Degeneration Caused by Ago2 Disruption.

Purpose: Argonaute proteins are key players in small RNA-guided gene silencing processes. Ago2 is the member of the Argonaute subfamily with slicer endonuclease activity and is critical for microRNA homeostasis and indispensable for biological development. However, the impact of Ago2 dysregulation in the retina remains to be fully explored. In this study, we studied the role of Ago2 in mouse retina. Methods: We explored the function of Ago2 in the mouse retina through an adeno-associated virus-mediated Ago2 disruption mouse model. An ERG was carried out to determine the retinal function. Spectral domain optical coherence tomography, fundus photographs, and immunostaining were performed to investigate the retinal structure. A quantitative RT-PCR assay was used to determine the expression of noncoding RNAs. Results: Both silencing and overexpression of Ago2 in mouse retina resulted in significant retinal morphological alterations and severe impairment of retinal function, mainly with a thinned outer nuclear layer, shortened inner segment/outer segment, and diminished ERG responses. Furthermore, Ago2 disruption resulted in alterations of noncoding RNAs in retina. Conclusions: Our finding demonstrated that Ago2 interruption led to severe retinal degeneration, suggested that Ago2 homeostasis contributed to retinal structural and functional maintenance.

Stem Cell-Based Regeneration and Restoration for Retinal Ganglion Cell: Recent Advancements and Current Challenges.

Glaucoma is a group of irreversible blinding eye diseases characterized by the progressive loss of retinal ganglion cells (RGCs) and their axons. Currently, there is no effective method to fundamentally resolve the issue of RGC degeneration. Recent advances have revealed that visual function recovery could be achieved with stem cell-based therapy by replacing damaged RGCs with cell transplantation, providing nutritional factors for damaged RGCs, and supplying healthy mitochondria and other cellular components to exert neuroprotective effects and mediate transdifferentiation of autologous retinal stem cells to accomplish endogenous regeneration of RGC. This article reviews the recent research progress in the above-mentioned fields, including the breakthroughs in the fields of in vivo transdifferentiation of retinal endogenous stem cells and reversal of the RGC aging phenotype, and discusses the obstacles in the clinical translation of the stem cell therapy.

Genetic Screening Revealed Latent Keratoconus in Asymptomatic Individuals.

PURPOSE: To adopt molecular screening in asymptomatic individuals at high risk of developing keratoconus as a combinative approach to prevent subclinical patients from post-refractive surgery progressive corneal ectasia. METHODS: In this study, 79 Chinese and nine Greek families with keratoconus were recruited, including 91 patients with clinically diagnosed keratoconus as well as their asymptomatic but assumptive high-risk first-degree relatives based on underlying genetic factor. Mutational screening of VSX1, TGFBI, and ZEB1 genes and full clinical assessment including Pentacam Scheimpflug tomography were carried out in these individuals. RESULTS: Five variants in VSX1 and TGFBI genes were identified in three Chinese families and one Greek family, and four of them were novel ones. Surprisingly, ultra-early corneal changes in Belin/Ambrosio Enhanced Ectasia Display of Pentacam corneal topography together with co-segregated variants were revealed in the relatives who had no self-reported symptoms. CONCLUSIONS: Variants of VSX1 and TGFBI genes identified in both the clinically diagnosed and subclinical patients may cause the keratoconus through an autosomal dominant inheritance pattern, with different variable expressivity. Combining genetic with Belin/AmbrosioEnhanced Ectasia Display can be used to identify patients with latent keratoconus. This study indicates that genetic testing may play an important supplementary role in re-classifying the disease manifestation and evaluating the preoperative examination of refractive surgery.