From Bench to Bed: The Current Genome Editing Therapies for Glaucoma

Glaucoma is a group of optic neuropathies featured by degeneration of retinal ganglion cells and loss of their axons in the optic nerve. The only currently approved therapies focus on lowering intraocular pressure with medication and surgery. Over the previous few decades, technological advances and research progress regarding pathogenesis has brought glaucomatous gene therapy to the forefront. In this review, we discuss the three current genome editing methods and potential disease mechanisms of glaucoma. We further summarize different genome editing strategies that are being developed to target a number of glaucoma-related genes and pathways from four aspects including strategies to lower intraocular pressure, neuroprotection, RGC and optic nerve neuro-regeneration, and other strategies. In summary, genome therapy is a promising therapy for treating patients with glaucoma and has great potential to be widely applied in clinical practice.

The role of inflammation and cortisol in the relationship between social cognition abilities and later emotional or behavioural problems: evidence from a UK birth cohort

Introduction

Deficits in social cognition have been associated with the onset of emotional and behavioural problems, but the biological mechanisms underlying this relationship remain unclear.

Objectives

This study examined whether diurnal cortisol patterns, systemic inflammation, or both, explained the association between social cognition difficulties and subsequent emotional and behavioural symptoms.

Methods

The sample consisted of 714 individuals from the Avon Longitudinal Study of Parents and Children (ALSPAC) with valid data on cortisol measures (age 15 years) and emotional or behavioural problems (age 17 years). Social cognition abilities were measured at 8, 11, and 14 years old. Inflammation was measured using serum levels of interleukin 6 (IL-6, age 9 years) and C-reactive protein (CRP, age 9 and 16 years). Bayesian structural equation modelling was used to investigate the mediating effect of cortisol or inflammation on the association between social cognitive difficulties and emotional or behavioural problems.

Results

Children with social cognition difficulties were associated with later emotional and behavioural problems. Flattened diurnal cortisol slope was associated with the hyperactivity/inattention problem two years later. Mediation analyses revealed that lower morning cortisol significantly mediated the associations between social communication difficulties at 8 years with hyperactivity/inattention and conduct problems in adolescence, with the adjustment of inflammation and all covariates. Systemic inflammation was not related to social cognitive difficulties or future emotional and behavioural problems.

Conclusions

The finding suggests that social cognition is related to cortisol activities longitudinally. It also expands the evidence that adolescents with behavioural problems are characterised by hypoactivity of the hypothalamic-pituitary-adrenal (HPA) axis.

Disclosure

No significant relationships.

[The in vivo imaging of zebrafish for chemical vascular toxicity assessment]

Objective: To evaluate the vascular toxicity of chemicals by a real-time observation approach using the transgenic zebrafish. Methods: The spatiotemporal vascular alterations of transgenic zebrafish after chemical exposure were assessed by laser confocal microscopy and high-content screening analysis, respectively. Results: The method using Laser Confocal Microscopy (LCM) is easier to operate and yields high-resolution images, while it is lower throughput and inefficient. In contrast, high-content analysis (HCA) analysis obtains high-quality data of vascular toxicity manifesting whole blood vasculature, whereas it requires delicate operation procedures and advanced experimental conditions. Conclusion: Two kinds of zebrafish imaging methods each have advantages and disadvantages. LCM is suitable for the evaluation of a small number of chemicals. HCA, a cutting-edge technology, has great potential for chemical safety assessment allowing high throughput vascular toxicity tests of a good number of chemicals at a time.

The roles of mitochondrial dynamics and NLRP3 inflammasomes in the pathogenesis of retinal light damage

With the widespread popularity of electronic products and the diversification of lighting equipment, ocular photochemical damage caused by light has attracted research attention. Although such equipment mainly cause damage to the retina, the specific pathogenesis has not been systematically elucidated. Thus, the goal of this study was to explore the relationship between mitochondrial dysfunction and the activation of the NOD-like receptor protein 3 (NLRP3) inflammasome in retinal cell death caused by light damage. We used a white light-emitting diode source to establish a mouse model of retinal light damage and observed significant changes of retinal structure and an impairment of visual function. Further experiments revealed that dynamin-related protein 1 (Drp1)-mediated excessive mitochondrial fission induced overproduction of reactive oxygen species in the retinal cells, leading to apoptosis, activation of microglia, and formation of the NLRP3 inflammasome. This, in turn, triggered a series of inflammatory cascade reactions, leading to pyroptosis. We also carried out red light and Drp1 inhibitor treatment and found that retinal damage and the decline in visual function caused by white light could be partially ameliorated. In conclusion, this study clarified the association between mitochondrial dynamics and the NLRP3 inflammasome in retinal light damage and provides opportunities for therapeutic intervention.

CaMK II -induced Drp1 phosphorylation contributes to blue light-induced AIF-mediated necroptosis in retinal R28 cells

Retinal damage caused by blue light has become an important public health concern. Mitochondria have been found to play a key role in light-induced retinal cell death. In this study, we aimed to clarify the molecular mechanism involved in mitochondrion-related retinal cell damage caused by blue light, the major component of light-emitting diodes (LEDs). Our results show that blue light (450 nm, 300lux)-induced R28 cell death is caspase independent and can be attenuated by necrostatin-1. Apoptosis-inducing factor (AIF) cleavage and translocation to the nucleus are involved in the cell death progress. Blue light exposure causes mitochondrial fragmentation, which is mediated by phosphorylation at dynamin-related protein 1 (Drp1) Ser⁶¹⁶ site, but it does not alter the protein levels of fission or fusion machinery. Knocking down Drp1 or treatment with Drp1 inhibitor Mdivi-1 protects R28 cells from blue light. Overproduction of reactive oxygen species (ROS) is induced by blue light. The ROS scavenger Trolox decreases Drp1 Ser⁶¹⁶ phosphorylation level and mitochondrial fragmentation upon blue light exposure. Moreover, Calcium/calmodulin-dependent protein kinase II (CaMKII) inhibitor KN93 blocks Drp1 phosphorylation and rescues mitochondrial fragmentation and AIF-mediated cell death caused by blue light. In conclusion, our data suggest that the CaMKII-Drp1 pathway plays a major role in blue light-induced AIF-mediated retinal cell damage.

Transneuronal Degeneration in the Brain During Glaucoma

The death of retinal ganglion cells (RGCs) is a key factor in the pathophysiology of all types of glaucoma, but the mechanism of pathogenesis of glaucoma remains unclear. RGCs are a group of central nervous system (CNS) neurons whose soma are in the inner retina. The axons of RGCs form the optic nerve and converge at the optic chiasma; from there, they project to the visual cortex via the lateral geniculate nucleus (LGN). In recent years, there has been increasing interest in the dysfunction and death of CNS and retinal neurons caused by transneuronal degeneration of RGCs, and the view that glaucoma is a widespread neurodegenerative disease involving CNS damage appears more and more frequently in the literature. In this review, we summarize the current knowledge of LGN and visual cortex neuron damage in glaucoma and possible mechanisms behind the damage. This review presents an updated and expanded view of neuronal damage in glaucoma, and reveals new and potential targets for neuroprotection and treatment.

Single-cell RNA sequencing: A new opportunity for retinal research

Single-cell RNA sequencing (scRNA-seq) is a technology for single-cell transcriptome analysis that can be used to characterize complex dynamics of various retinal cell types. It provides deep scrutiny into the gene expression character of diverse cell types, lending insight into all the biological processes being carried out. The scRNA-seq is an alternative to regular RNA-seq, which does not achieve cellular heterogeneity. The retina, is a part of the central nervous system (CNS) and consists of six types of neurons and several types of glial cells. Studying retinal cell heterogeneity is important for understanding retinal diseases. Currently, scRNA-seq is employed to assess retina development and retinal disease pathogenesis and has improved our understanding of the relationship between the retina, its visual pathways, and the brain. Moreover, this technology provides new ideas on the sensitivity and molecular mechanisms of cell subtypes involved in retinal-related diseases. The application of scRNA-seq technology has given us a deeper understanding of the latest advancements and challenges in retinal development and diseases. We advocate scRNA-seq as one of the important tools for developing novel therapies for retinal diseases. This article is categorized under: RNA Methods > RNA Analyses in Cells RNA in Disease and Development > RNA in Development RNA in Disease and Development > RNA in Disease.

Pathogenesis and prospects for therapeutic clinical application of noncoding RNAs in glaucoma: Systematic perspectives

Noncoding ribonucleic acids (ncRNAs) are an increasingly studied class of RNA molecules with extensive biological activities, including important roles in human development, health, and disease. Glaucoma is a neurodegenerative disease of the retina, and one of the leading causes of blindness worldwide. However, the specific roles of ncRNAs in the development and progression of glaucoma are unclear, and related reports are fragmented. An in‐depth understanding of ncRNAs participating in the pathogenesis and progression of glaucoma would be helpful for opening up new avenues to facilitate the early diagnosis and clinical treatment. Therefore, in this review, we aimed to discuss the current research progress, the potentialfuture clinical applications and the research limitations of three critical classes of ncRNAs in glaucoma, namely microRNAs, long noncoding RNAs, and circular RNAs.

Diammonium glycyrrhizinate lipid ligand ameliorates lipopolysaccharide-induced acute lung injury by modulating vascular endothelial barrier function

The aim of the present study was to investigate the effects of diammonium glycyrrhizinate lipid ligand (DGLL) treatment on acute lung injury (ALI) and pulmonary edema induced by lipopolysaccharide (LPS) in Sprague-Dawley rats. Rats orally received 30, 60 and 120 mg/kg DGLL. After 1 h, the rat ALI model was established by LPS (10 mg/kg) intraperitoneal injection. After 6 h, lung injury was evaluated using hematoxylin and eosin staining techniques. Pulmonary edema was evaluated using lung wet-dry weight ratio, protein concentrations in the bronchoalveolar lavage fluid (BALF) and Evans blue (EB) extravasation in lung tissue. The expression levels of tumor necrosis factor (TNF)-α and interleukin (IL)-1β in lung tissues were measured using ELISA. Myeloperoxidase (MPO) expression levels were detected by immunohistochemical staining. Western blotting was used to measure the expression level changes of intercellular adhesion molecule (ICAM)-1, as well as adherent and tight junction proteins, including vascular endothelial (VE)-cadherin, zonula occludens (ZO)-1, occludin and junctional adhesion molecule (JAM)-1 that were associated with pulmonary inflammation and microvascular permeability. DGLL treatment significantly alleviated ALI induced by LPS, which was demonstrated by reduction of MPO-positive cells and expression levels of TNF-α, IL-1β and ICAM-1 in rat lung tissues. In addition, DGLL abrogated LPS-induced pulmonary edema, decreased the protein concentration in BALF and reduced EB extravasation. DGLL also reversed the reduced expression of VE-cadherin and tight junction proteins, including ZO-1, occludin and JAM-1 in the lung tissues caused by LPS. In conclusion, DGLL exhibits a protective effect on LPS-induced rat ALI, which is associated with the inhibition of inflammatory cell infiltration and microvascular barrier disruption. The present results provide a theoretical basis for the application of DGLL for the potential clinical treatment of ALI.

c-FLIP regulates pyroptosis in retinal neurons following oxygen-glucose deprivation/recovery via a GSDMD-mediated pathway

Cellular FLICE-inhibitory protein (c-FLIP), an anti-apoptotic regulator, shows remarkable similarities to caspase-8, which plays a key role in the cleavage of gasdermin D (GSDMD). It has been reported that the oxygen-glucose deprivation/recovery (OGD/R) model and lipopolysaccharide (LPS)/adenosine triphosphate (ATP) treatment could induce inflammation and pyroptosis. However, the regulatory role of c-FLIP in the pyroptotic death of retinal neurons is unclear. In this study, we hypothesized that c-FLIP might regulate retinal neuronal pyroptosis by GSDMD cleavage. To investigate this hypothesis, we induced retinal neuronal damage in vitro (OGD/R and LPS/ATP) and in vivo (acute high intraocular pressure [aHIOP]). Our results demonstrated that the three injuries triggered the up-regulation of pyroptosis-related proteins, and c-FLIP could cleave GSDMD to generate a functional N-terminal (NT) domain of GSDMD, causing retinal neuronal pyroptosis. In addition, c-FLIP knockdown in vivo ameliorated the already established visual impairment mediated by acute IOP elevation. Taken together, these findings revealed that decreased c-FLIP expression protected against pyroptotic death of retinal neurons possibly by inhibiting GSDMD-NT generation. Therefore, c-FLIP might provide new insights into the pathogenesis of pyroptosis-related diseases and help to elucidate new therapeutic targets and potential treatment strategies.

Coverage and effectiveness of hypertension screening in different altitudes of Tibet autonomous region

BACKGROUND

Tibet is an autonomous region in China located around an average altitude of 4500 m above sea level. Since 2012 the local government of Tibet has been providing free physical examinations, including screening for hypertension. However, the coverage and effectiveness of this free program have not been uncovered. This study aims to assess the coverage and effectiveness of hypertension screening and management program in 3 altitude levels of Tibet, and also the determinants of the success of the screening program.

METHODS

A stratified cluster survey was conducted among 1636 residents aged 18 years or over in three different altitude areas in Tibet. We adjusted for age and sex based on national census data and used weighted logistic regression models to find factors associated with hypertension screening.

RESULTS

The coverage of the hypertension screening program evaluated by participation rate in the previous screening was 94.9%, while 24.7% (95% CI: 22.1-27.3%) of them were diagnosed with hypertension. Females and alcohol drinkers were more likely to be screened. Among those diagnosed with hypertension, 28.7% had it under control. High altitude areas had a high proportion of controlled hypertension. The overall rate of controlled hypertension in high, moderate and low altitude areas was 35.1% (95% CI: 24.8-45.3%), 32.7% (95% CI: 22.2-43.2%) and 23.7% (95% CI: 14.7-32.6%), respectively. Younger aged persons were more likely to have better control of their hypertension.

CONCLUSIONS

The coverage of hypertension screening in Tibet was high, especially in the low altitude areas. However, the effectiveness of hypertension control was low, indicating a need to implement the treatment adherence routines into the current screening interventions.

Identification of GJA3 p.S50P Mutation in a Chinese Family with Autosomal Dominant Congenital Cataract and Its Underlying Pathogenesis

Congenital cataract refers to a lens opacity caused by multiple etiological factors, including genetic mutation, abnormal metabolism of the lens, and infection. Currently, there are >100 known disease-causing genes as well as 60 known mutations in the Cx46 gene (Gap junction alpha-3, GJA3) associated with congenital cataracts. Dysfunction of gap junctions impairs homeostasis in lens cells, thereby inducing cataract pathogenesis. This study aims to identify the disease-causing mutation in a family with congenital cataract, and to further explore the possible pathogenic mechanism resulting from this mutation. We identified that a recurrent heterozygous missense mutation c.T148C (p.S50P) in GJA3 was the pathogenic mutation in this family. Previously, this mutation was found in a British family causing bilateral congenital cataract. We further demonstrated that CX46 wild type (WT) was coupled through functional gap junctions in HeLa cells, while mutant Cx46 S50P lost this ability. Moreover, the half-life of Cx46 S50P was longer than that of Cx46 WT, Cx46 S50P protein was also localized to the endoplasmic reticulum and induced more reactive oxygen species compared to Cx46 WT, which may lead to dysregulation of Cx46-formed gap junction. Collectively, our study defines the genetics basis of a congenital cataract family as well as the cellular mechanisms of mutant Cx46 S50P, and provides useful information for further studies of the pathogenesis and therapeutic strategy for treating congenital cataract.

FUN14 domain-containing 1-mediated mitophagy suppresses interleukin-1β production in macrophages

Mitochondria play a critical role in triggering immune response. Although recent evidence indicates that autophagy/mitophagy can suppress inflammation via regulation of mitochondrial homeostasis, limited information is available regarding physiological regulation of mitochondria-controlled inflammation. In this study, we investigated FUN14 domain containing 1 (FUNDC1)-mediated mitophagy in the regulation of interleukin-1β (IL-1β) in vitro and in vivo, wild-type FUNDC1 and its mitophagy defective Y18A/L21A mutant were analyzed in bone marrow-derived macrophages (BMDMs)for their effects on IL-1β expression and mitochondrial damage. The current study identified that LPS plus nigericin stimulation induced NLR family pyrin domain containing 3 (NLRP3) inflammasome activation, which was detected by IL-1β expression. Moreover, FUNDC1-mediated mitophagy promoted the alleviation of intracellular reactive oxygen species (ROS). IL-1β production was suppressed by the overexpression of wild-type FUNDC1, but not the Y18A/L21A mutant. Our results suggest that FUNDC1 suppresses LPS plus nigericin-mediated IL-1β production through its regulatory effect on mitophagy, which will greatly promote the understanding of mitophagy-related protein in the regulation of immune response.

Normal vitreous promotes angiogenesi via the epidermal growth factor receptor

Vitreous, a transparent tissue in our body, contains anti-angiogenesis factors. Our previous work reported that vitreous activates the signaling pathway of epidermal growth factor receptor (EGFR), which plays a critical role in angiogenesis. The aim of this study was to determine the role of EGFR in vitreous-induced angiogenesis-related cellular responses in vitro. Using a pharmacologic and molecular approach, we found that vitreous increased proliferation and migration via EGFR in human umbilical vein endothelial cells (HUVECs). Furthermore, we demonstrated that vitreous promoted tube formation via EGFR in HUVECs. Subsequently, depletion of EGFR using CRISPR/Cas9 and blockage with EGFR inhibitor AG1478 suppressed vitreous-induced Akt activation and cell proliferation, migration, and tube formation in HUVECs. The significance of the angiogenic effect derived from vitreous demonstrates the importance of vitreous in the ocular physiology and the pathobiology of angiogenesis-related ophthalmic diseases, such as proliferative diabetic retinopathy.

RSK3 mediates necroptosis by regulating phosphorylation of RIP3 in rat retinal ganglion cells

Receptor-interacting protein 3 (RIP3) plays an important role in the necroptosis signaling pathway. Our previous studies have shown that the RIP3/mixed lineage kinase domain-like protein (MLKL)-mediated necroptosis occurs in retinal ganglion cell line 5 (RGC-5) following oxygen-glucose deprivation (OGD). However, upstream regulatory pathways of RIP3 are yet to be uncovered. The purpose of the present study was to investigate the role of p90 ribosomal protein S6 kinase 3 (RSK3) in the phosphorylation of RIP3 in RGC-5 cell necroptosis following OGD. Our results showed that expression of RSK3, RIP3, and MLKL was upregulated in necroptosis of RGC-5 after OGD. A computer simulation based on our preliminary results indicated that RSK3 might interact with RIP3, which was subsequently confirmed by co-immunoprecipitation. Further, we found that the application of a specific RSK inhibitor, LJH685, or rsk3 small interfering RNA (siRNA), downregulated the phosphorylation of RIP3. However, the overexpression of rip3 did not affect the expression of RSK3, thereby indicating that RSK3 could be a possible upstream regulator of RIP3 phosphorylation in OGD-induced necroptosis of RGC-5 cells. Moreover, our in vivo results showed that pretreatment with LJH685 before acute high intraocular pressure episodes could reduce the necroptosis of retinal neurons and improve recovery of impaired visual function. Taken together, our findings suggested that RSK3 might work as an upstream regulator of RIP3 phosphorylation during RGC-5 necroptosis.

Whether miR-4293 rs12220909 variant affects cancer susceptibility: evidence from 11255 subjects

Background: miR-4293 rs12220909 polymorphism was reported associated with tumorigenesis, but the results are controversial. Thus, we planned to verify and obtain precise results.Methods: Databases were searched and reviewed up to November, 2019. Case-control studies which concern about the association between cancer risks and miR-4293 polymorphisms were all enrolled. The odds ratios (ORs) and 95% confidence intervals (CIs) calculated by the Z test were used to assess the underlying links. We also prospected how the miR-4293 impacts biological process through its target genes.Result: Finally, there are seven independent studies meet the enrolled criteria, along with 5147 cases and 6108 healthy controls. We revealed that there is a significant decrease effect of miR-4293 rs12220909 to cancer risks in heterozygote genetic model (BA vs. AA: OR = 0.857, p = .032), the similar results were also uncovered in PB control group, lung cancer and the studies conform to HWE. Results from GO items and KEGG pathway analysis illustrated that myeloid cell development, transcription factor complex, RNA polymerase II regulatory region DNA binding were regulated by miR-4293.Conclusion: In summary, our meta-analysis chase down heterozygote rs12220909 polymorphism of miR-4293 is a protective factor to cancer initiation, especially for lung cancer.

Characterization and genomic function analysis of phenanthrene-degrading bacterium Pseudomonas sp. Lphe-2

A stain of Pseudomonas sp. Lphe-2, which could degrade phenanthrene as the main carbon and energy source, was isolated from the aerobic sludge of a coking plant. Then its biodegradation characteristics, whole genome sequence and biodegradation pathway were examined. The Lphe-2 strain exhibited broad-spectrum degradation activities for various polycyclic aromatic hydrocarbons (PAHs), including naphthalene (NAP), phenanthrene (PHE), and pyrene (PYR). Under the optimal conditions, the degradation efficiency of phenanthrene (100 mg/L) is 92.76% on the 7th day, and 2-carboxybenzaldehyde and 1-hydroxy-2-naphthoic acid are the major metabolites found in phenanthrene metabolism. Genomic analysis of Pseudomonas sp. Lphe-2 showed that a total of 3879 genes from the Lphe-2 strain were annotated based on the COG classification, and the genomic information was annotated to 185 metabolic pathways. Based on the intermediate metabolites detected by Gas Chromatography-Mass Spectrometer (GC-MS) and all potential phenanthrene-degrading genes identified by BLAST search, a phenanthrene biodegradation pathway of Lphe-2 strain was proposed. These results suggested that Lphe-2 strain has a good prospect in the bioremediation of PAHs pollution.

Determination of Campesterol, Stigmasterol, and Beta-Sitosterol in Saw Palmetto Raw Materials and Dietary Supplements by Gas Chromatography: Collaborative Study

An interlaboratory study was conducted to evaluate a method for the determination of campesterol, stigmasterol, and beta-sitosterol in saw palmetto raw materials and dietary supplements at levels >1.00 mg/100 g based on a 23 g sample. Test samples were saponified at high temperature with ethanolic KOH solution. The unsaponifiable fraction containing phytosterols (campesterol, stigmasterol, and beta-sitosterol) was extracted with toluene. Phytosterols were derivatized to trimethylsilyl ethers and then quantified by gas chromatography with hydrogen flame ionization detection. Twelve blind duplicates, one of which was fortified, were successfully analyzed by 10 collaborators. Recoveries were obtained for the sample that was fortified. The results were 99.8, 111, and 111% for campesterol, stigmasterol, and beta-sitosterol, respectively. For repeatability, the relative standard deviation (RSDr) ranged from 3.93 to 17.3% for campesterol, 3.56 to 22.7% for stigmasterol, and 3.70 to 43.9% for beta-sitosterol. For reproducibility, the RSDR ranged from 7.97 to 22.6%, 0 to 26.7%, and 5.27 to 43.9% for campesterol, stigmasterol, and beta-sitosterol, respectively. Overall, the Study Director approved 5 materials with acceptable HorRat values for campesterol, stigmasterol, and beta-sitosterol ranging from 1.02 to 2.16.

Determination of β-Carotene in Supplements and Raw Materials by Reversed-Phase High Pressure Liquid Chromatography: Collaborative Study

Twelve laboratories representing 4 countries participated in an interlaboratory study conducted to determine all-trans-β-carotene and total β-carotene in dietary supplements and raw materials. Thirteen samples were sent as blind duplicates to the collaborators. Results obtained from 11 laboratories are reported. For products composed as softgels and tablets that were analyzed for total β-carotene, the reproducibility relative standard deviation (RSDR) ranged from 3.35 to 23.09% and the HorRat values ranged from 1.06 to 3.72. For these products analyzed for trans β-carotene, the reproducibility relative standard deviation (RSDR) ranged from 4.28 to 22.76% and the HorRat values ranged from 0.92 to 3.37. The RSDr and HorRat values in the analysis of a beadlet raw material were substantial and it is believed that the variability within the material itself introduced significant variation in subsampling. The method uses high pressure liquid chromatography (LC) in the reversed-phase mode with visible light absorbance for detection and quantitation. If high levels of α-carotenes are present, a second LC system is used for additional separation and quantitation of the carotene species. It is recommended that the method be adopted as an AOAC Official Method.

Pin1 Is Regulated by CaMKII Activation in Glutamate-Induced Retinal Neuronal Regulated Necrosis

In our previous study, we reported that peptidyl-prolyl isomerase 1 (Pin1)-modulated regulated necrosis (RN) occurred in cultured retinal neurons after glutamate injury. In the current study, we investigated the role of calcium/calmodulin-dependent protein kinase II (CaMKII) in Pin1-modulated RN in cultured rat retinal neurons, and in an animal in vivo model. We first demonstrated that glutamate might lead to calcium overloading mainly through ionotropic glutamate receptors activation. Furthermore, CaMKII activation induced by overloaded calcium leads to Pin1 activation and subsequent RN. Inactivation of CaMKII by KN-93 (KN, i.e., a specific CaMKII inhibitor) application can decrease the glutamate-induced retinal neuronal RN. Finally, by using an animal in vivo model, we also demonstrated the important role of CaMKII in glutamate-induced RN in rat retina. In addition, flash electroretinogram results provided evidence that the impaired visual function induced by glutamate can recover after CaMKII inhibition. In conclusion, CaMKII is an up-regulator of Pin1 and responsible for the RN induced by glutamate. This study provides further understanding of the regulatory pathway of RN and is a complementary mechanism for Pin1 activation mediated necrosis. This finding will provide a potential target to protect neurons from necrosis in neurodegenerative diseases, such as glaucoma, diabetic retinopathy, and even central nervous system diseases.

A Novel AMELX Mutation, Its Phenotypic Features, and Skewed X Inactivation

Amelogenesis imperfecta (AI) is a group of genetic disorders of defective dental enamel. Mutation of AMELX encoding amelogenin on the X chromosome is a major cause of AI. Here we report a Chinese family with hypoplastic and hypomineralized AI. Whole exome analysis revealed a novel mutation c.185delC in exon 5 of AMELX causing the frame shift p.Pro62ArgfsTer47 (or p.Pro62Argfs*47). By sequencing of polymerase chain reaction products and T-vector clones, the mutation was confirmed as homozygous in the proband, hemizygous in her father, and heterozygous in her mother. The proband and her father had small and yellowish teeth with thin and rough enamel that was radiographically indistinguishable from the underlying dentin. Scanning electronic microscopy of 1 maternal tooth showed cracks and exposed loosely packed enamel prisms in affected areas. Consistent with a 25:75 skewing of X inactivation in the peripheral blood DNA as measured by androgen receptor allele methylation, the surface of the mother’s tooth had alternating vertical ridges of transparent normal and white chalky enamel in a 34:66 ratio. In summary, this study provides one of the few phenotypic comparisons of hemizygous and homozygous AMELX mutations and suggests that the skewing of X inactivation in AI contributes to the phenotypic variations in heterozygous carriers of X-linked AI.