Lycopene-Loaded Microemulsion Regulates Neurogenesis in Rats with Aβ-Induced Alzheimer’s Disease Rats Based on the Wnt/β-catenin Pathway

Objective. To investigate the effects of lycopene-loaded microemulsion (LME) on the cognitive function and neurogenesis in the dentate gyrus (DG) of the hippocampus and subventricular (SVZ) region of rats with amyloid β- (Aβ-) induced Alzheimer’s disease (AD) and its mechanism based on the Wnt/β-catenin pathway. Methods. Healthy Wistar rats were divided into four groups: the blank control (CON), AD control, traditional lycopene (LOO), and LME groups. The CON and AD groups were fed with normal saline, while the LOO group was fed with traditional lycopene, and the LME group was fed with lycopene-loaded microemulsion. Behavioral tests were performed after three weeks of gastric administration. Immunofluorescence-labeled cells were used to observe the differentiation and maturation of new nerve cells in the DG of the hippocampus and SVZ region. qRT-PCR and Western blotting detected the expression of neurogenesis genes and Wnt/β-catenin pathway-related proteins, respectively. Results. On the Morris water maze test, LME rats had significantly shortened movement trajectory on the searching platform, reduced escape latency time, and increased residence time on the original platform quadrant. In addition, more LME rats crossed the platform when it was removed. Thus, LME can improve the spatial learning and memory of Aβ-induced AD rats. On qRT-PCR, LME significantly increased Reelin, Nestin, and Pax6 gene expressions, which regulate neurogenesis. Immunofluorescence showed that LME could significantly increase BrdU+, Dcx+, BrdU+/Neun+, BrdU+/Dcx+ cells in the DG and SVZ regions, thus promoting neurogenesis. LME also reduced the number of Iba1+ and Iba1+/BrdU+ cells, thus reducing the neuroinflammatory response. On Western blot, LME upregulated the Wnt/β-catenin pathway by upregulating Wnt3a, β-catenin, Disheveled (Dvl), and p-GSK3β and downregulating p-β-catenin and GSK3β. Conclusion. LME attenuates cognitive impairment in Aβ-induced AD rats by promoting neurogenesis in the hippocampus and SVZ region through upregulating the Wnt/β-catenin pathway.

Management of Retinal Detachment Associated with Morning Glory Disc Syndrome

We report a case of morning glory disc anomaly in a young patient with tractional retinal detachment successfully repaired with complex pars plana vitrectomy, membrane peel, laser, and oil tamponade. A 19-year-old female with a history of right morning glory disc anomaly associated with PAX6 gene mutation presented with floaters, photopsia, central scotoma, and visual acuity (VA) of 1/200. A complex macula-involving tractional retinal detachment centered around the optic nerve with a morning glory disc anomaly. Retinal detachment was treated with 25-gauge pars plana vitrectomy with difficult separation of the posterior hyaloid. Fibrous preretinal membranes were peeled, a temporal relaxing retinotomy was required, subretinal fluid was drained through a superonasal retinotomy during air-fluid exchange, endolaser was applied, and tamponade was achieved with 1,000-centistoke silicone oil. The retina remained attached at 1-year follow-up, with VA count fingers throughout. Morning glory disc is a rare congenital anomaly associated with PAX6 gene mutation that most often occurs unilaterally. It is rarely associated with tractional retinal detachment. Optimization of visual outcome is imperative despite a poor visual prognosis.

Expanding the Phenotypic Spectrum of PAX6 Mutations: From Congenital Cataracts to Nystagmus

Background: Congenital aniridia is a complex ocular disorder, usually associated with severe visual impairment, generally caused by mutations on the PAX6 gene. The clinical phenotype of PAX6 mutations is highly variable, making the genotype–phenotype correlations difficult to establish. Methods: we describe the phenotype of eight patients from seven unrelated families with confirmed mutations in PAX6, and very different clinical manifestations. Results: Only two patients had the classical aniridia phenotype while the other two presented with aniridia-related manifestations, such as aniridia-related keratopathy or partial aniridia. Congenital cataracts were the main manifestation in three of the patients in this series. All the patients had nystagmus and low visual acuity. Conclusions: The diagnosis of mild forms of aniridia is challenging, but these patients have a potentially blinding hereditary disease that might present with a more severe phenotype in future generations. Clinicians should be aware of the mild aniridia phenotype and request genetic testing to perform an accurate diagnosis.

Persistent iris vessels in a case of aniridia

Congenital aniridia is caused by a mutation in the PAX6 gene [1] and is characterized by partial or complete absence of iris tissue. Apart from the hypoplasia of iris tissue, other ocular features such as foveal hypoplasia, nystagmus, aniridia-related keratopathy, Peters anomaly, Axenfeld-Rieger anomaly and glaucoma are seen in these eyes [1,2]. Cases have been reported with persistent pupillary membranes [3] and iris strands [4].

Cell signaling pathways in human mutant PAX6 corneal cells: an in vitro model for aniridia-related keratopathy

ABSTRACTPURPOSETo establish an in vitro model of aniridia-related keratopathy (ARK) using CRISPR/Cas9 engineered human keratocytes with mutations in the PAX6 gene, and to study the Notch Homolog 1, Translocation-Associated (Notch1), sonic hedgehog (SHH), mammalian target of rapamycin (mTOR), and Wnt/β-catenin signaling pathways in the PAX6 mutant keratocytes.METHODSPrimary human keratocytes were isolated from healthy corneas. Keratocytes were transduced with Cas9 lentiviral particles in order to create cells stably expressing Cas9 nuclease. Lentiviral particles carrying PAX6 sgRNA were transduced into the Cas9 keratocytes creating mutants. Analysis of signaling pathways was assessed by RT-qPCR for gene expression and western blot for protein expression.RESULTSHuman keratocytes stably expressing Cas9 nuclease were created. Keratocytes carrying PAX6 gene mutation were successfully generated. PAX6 mutant keratocytes showed modified expression patterns of extracellular matrix components such as collagens and fibrotic markers. Analysis of the Notch1, SHH, mTOR, and Wnt/β-catenin signaling pathways in the PAX6 mutant keratocytes revealed altered gene and protein expression of the key players involved in these pathways.CONCLUSIONSA properly functioning PAX6 gene in keratocytes is crucial for the regulation of signaling pathways important for cell fate determination, proliferation, and inflammation. Pax6 mutation in the in vitro settings leads to changes in these pathways which resemble those found in corneas of patients with ARK.

Detection of a novel PAX6 mutation in a Chinese family with multiple ocular abnormalities

Background: Aniridia is a congenital, panocular disease affecting the cornea, anterior chamber angle, iris, lens, retina and optic nerve. PAX6 loss-of-function mutations were the most common cause of aniridia .Mutations throughout the PAX6 gene have been linked to a range of ophthalmic abnormalities, with distinct mutations at a given site within this gene leading to distinct phenotypic findings.This s tudy aimed to characterize genetic mutations associated with congenital aniridia in a Chinese family. Methods: The proband and the proband’s brother of this family underwent comprehensive ophthalmologic examinations as well as exome sequencing, with Next Generation Sequencing being used to confirm these results. Results: A novel mutation (c.114_119delinsAATTTCC:p.Pro39fs) in the PAX6 gene was identified in subjects III-2 and III-3 in these family, and both of these subjects exhibited complete aniridia, cataracts, glaucoma, high myopia, and foveal hypoplasia. Conclusions: We identified a novel PAX6 frameshift heterozygous deletion mutation in a Chinese family and determined that this mutation was a probable cause of various eye abnormalities in carriers.

A high frequency of the PAX6 gene 3'-cis-regulatory region deletions in Russian aniridia patients

Врожденная аниридия (OMIM#106210) (ВА) - наследственное аутосомно-доминантное заболевание, ассоциированное с внутригенными мутациями гена PAX6 или крупными хромосомными аберрациями с вовлечением региона 11p13 в гетерозиготном состоянии. Проведено изучение особенностей спектра мутаций гена PAX6 и региона 11p13 в когорте пациентов с ВА из России. Обследованы 184 пациента из 152 неродственных семей. У 17 пациентов из 12 неродственных семей в регионе 11p13 обнаружены сходные делеции дистантной 3'-цис-регуляторной области гена PAX6 размером 0,3-1,5 млн п.н. Частота 3'-цис делеций составила 8% (12/152) и превысила частоту обычной нонсенс мутации в гене PAX6 c.718C>T (9/152, 6%). Высокая частота делеций указывает на возможно общий механизм их образования в «горячем» локусе региона 11p13. Aniridia (OMIM 106210) is an autosomal dominant congenital disorder caused by heterozygous PAX6 intragenic mutations or chromosome 11p13 rearrangements. Molecular genetic study aimed to determine PAX6 damage spectrum peculiarities in Russian cohort. 152 unrelated families with congenital aniridia (184 patients) underwent ophthalmic examination and DNA testing. 17 patients from 12 unrelated families (4 familial and 8 sporadic probands) shared likely the same 11p13 0.3-1.5 Mb deletion affecting PAX6 downstream regulatory regions. The frequency of these deletions, 8% (12/152), was higher than PAX6 hotspot c.718C>T rate (8/152, 6%). A high rate of the deletions suggests a common underlying mechanism of its formation and points to 11p13 genomic region instability.