Glutamate-releasing BEST1 channel is a new target for neuroprotection against ischemic stroke with wide time window

Many efforts have been made to understand excitotoxicity and develop neuroprotectants for the therapy of ischemic stroke. The narrow treatment time window is still to be solved. Given that the ischemic core expanded over days, treatment with an extended time window is anticipated. Bestrophin 1 (BEST1) belongs to a bestrophin family of calcium-activated chloride channels. We revealed an increase in neuronal BEST1 expression and function within the peri-infarct from 8 to 48 h after ischemic stroke in mice. Interfering the protein expression or inhibiting the channel function of BEST1 by genetic manipulation displayed neuroprotective effects and improved motor functional deficits. Using electrophysiological recordings, we demonstrated that extrasynaptic glutamate release through BEST1 channel resulted in delayed excitotoxicity. Finally, we confirmed the therapeutic efficacy of pharmacological inhibition of BEST1 during 6-72 h post-ischemia in rodents. This delayed treatment prevented the expansion of infarct volume and the exacerbation of neurological functions. Our study identifies the glutamate-releasing BEST1 channel as a potential therapeutic target against ischemic stroke with a wide time window.

Progress in the research on clinical features of Bestrophinopathies and mutations in BEST1 gene / 中华实验眼科杂志

Bestrophinopathies are a group of inherited macular dystrophies caused by BEST1 gene mutations including Best vitelliform macular dystrophy, adult-onset vitelliform macular dystrophy, autosomal dominant vitreoretinochoroidopathy and autosomal recessive bestrophinopathy.The main pathological mechanism of bestrophinopathies is that the primary lesion located in the retinal pigment epithelium will affect the photoreceptor cells.The mutations in BEST1 gene not only result in macular lesions, but also potentially affect the development of eyeball, and even cause serious complications such as angle-closure glaucoma and choroidal neovascularization.It is highly heritable and clinically heterogeneous.The same pathogenic mutation site in BEST1 can lead to different clinical phenotypes, which are complex and varied and can bring great confusion to clinicians, causing misdiagnosis and missed diagnosis the disease.This review aimed to summarize and analyze the clinical manifestations of bestrophinopathies and the research progress in BEST1 gene mutations, so as to improve the understanding of clinicians toward this kind of disease and provide reference for clinical practice and future research.

Analysis of BEST1 gene mutation and clinical phenotype in two families with Best vitelliform macular dystrophy and autosomal recessive bestrophinopathy / 中华眼底病杂志

Objective:To report the BEST1 gene mutations and clinical phenotypes in two pedigrees with Best vitelliform macular dystrophy (BVMD) and autosomal recessive bestrophinopathy (ARB). Methods:A retrospective clinical study. From November 2019 to March 2021, in the Department of Ophthalmology of The First Affiliated Hospital of Zhengzhou University, the BVMD family (4 patients and 6 family members) and the ARB family (2 patients, 2 family members), a total of 6 patients and 8 normal family members were included in the study. Detailed medical history was obtained; best corrected visual acuity, fundus color photography, electrophysiology, optical coherence tomography and fundus autofluorescence examination were performed. The clinical characteristics for all patients in the two families were analyzed. Three milliliter peripheral venous blood of all participants in the family was collected, and the whole genomic DNA was extracted with gene sequencing using next-generation sequencing technology based on targeted capture. Compared with the database to identify the pathogenicity mutation sites, suspected pathogenic mutation sites were selected, then mutations in other members in the family was assayed by Sanger sequencing.Results:In family 1, the proband was demonstrated as typical BVMD, other patients were multifocal vitelliform macular dystrophy. The DNA sequencing result showed that all the 4 patients carried heterozygous missense mutations in exon 3 of BEST1 gene: c.240C>G (p.F80L) (M1) and 2 members carried this mutation, but without clinical phenotype. M1 was a likely-pathogenic mutation reported for the first time. In family 2, the proband and the other patient were diagnosed as ARB. The DNA result showed that the 2 patients carried heterozygous missense mutations in exon 5 and exon 2 of BEST1 gene: c.584C>T (p.A195V) (M2)、c.139C>A (p.R47S) (M3), and a heterozygous frameshift mutation in exon 3 of BEST1 gene: c.235dupT (p.S79Ffs*153) (M4). M2 was a pathogenic mutation reported previously. M3 variant was of undetermined significance. M4 was a first reported pathogenic mutation. Conclusions:The BEST1 gene mutation is the main cause of BVMD and ARB. Different mutation sites have different clinical phenotypes. BVMD and ARB have genetic and clinical heterogeneity.

Progress in the research on clinical features of Best vitelliform macular dystrophy and mutations in BEST1 gene / 国际眼科杂志(Guoji Yanke Zazhi)

Best vitelliform macular dystrophy ( BVMD ) is an autosomal dominant disease mostly caused by mutations in BEST1 gene. These mutations change the normal physiological functions of BEST1-encoded bestrophin-1 protein, and finally lead to a reduction of visual acuity. This review is composed of the following aspects: the structure and functions of BEST1 gene, the characteristics of the mutations, clinical features of BVMD, genotype-phenotype correlations as well as possible gene therapy. Our contribution serves for further research on BVMD and BEST1 gene.