Roles of Optineurin and Extracellular Vesicles in Glaucomatous Retinal Cell Loss.

OBJECTIVE: To explore the role of extracellular vesicles (EVs) in the pathogenesis of glaucoma caused by E50K mutation. METHODS: A photoreceptor cell line, RGC-5, was transfected with empty plasmids and plasmids expressing wild-type (WT) optineurin (OPTN) or E50K OPTN to investigate the effects of OPTN glaucoma as well as to identify the role of EVs in glaucoma pathology. The RGC-5 cells were also stimulated with glutamate, and their viability was evaluated using flow cytometry or CCK-8 assay. EVs were extracted, labeled with PKH-26, and added into the medium for normal RGC-5 culture, and the status of the cells was observed thereafter. RESULTS: WT OPTN overexpression, E50K OPTN, and glutamate stimulation induced apoptosis of RGC-5 cells. However, when glutamate stimulation was used as an add-on treatment, the degree of apoptosis in WT OPTN-overexpressing RGC-5 cells was significantly lower than that in E50K OPTN-expressing and normal RGC-5 cells. The viability of normal RGC-5 cells was reduced when co-cultured with WT OPTN-overexpressing RGC-5 or E50K OPTN-overexpressing RGC-5. EVs released by the latter two transfected lines similarly reduced normal RGC-5 survival. CONCLUSION: Our results indicate that WT OPTN overexpression may lead to photoreceptor apoptosis. However, overexpression also confers a degree of protection against high concentrations of extracellular glutamate. Additionally, EVs released by transfected RGC-5 cells may regulate the cell state. These findings may improve our understanding of the mechanisms of cell-cell interactions in pathological conditions, providing a basis for the use of EVs as novel targets for early diagnosis and treatment of glaucoma.

The Melastoma dodecandrum genome and the evolution of Myrtales.

Melastomataceae has abundant morphological diversity with high economic and ornamental merit in Myrtales. The phylogenetic position of Myrtales is still contested. Here, we report the chromosome-level genome assembly of Melastoma dodecandrum in Melastomataceae. The assembled genome size is 299.81 Mb with a contig N50 value of 3.00 Mb. Genome evolution analysis indicated that M. dodecandrum, Eucalyptus grandis, and Punica granatum were clustered into a clade of Myrtales and formed a sister group with the ancestor of fabids and malvids. We found that M. dodecandrum experienced four whole-genome polyploidization events: the ancient event was shared with most eudicots, one event was shared with Myrtales, and the other two events were unique to M. dodecandrum. Moreover, we identified MADS-box genes and found that the AP1-like genes expanded, and AP3-like genes might have undergone subfunctionalization. The SUAR63-like genes and AG-like genes showed different expression patterns in stamens, which may be associated with heteranthery. In addition, we found that LAZY1-like genes were involved in the negative regulation of stem branching development, which may be related to its creeping features. Our study sheds new light on the evolution of Melastomataceae and Myrtales, which provides a comprehensive genetic resource for future research.