Scleral hypoxia is a target for myopia control.

Worldwide, myopia is the leading cause of visual impairment. It results from inappropriate extension of the ocular axis and concomitant declines in scleral strength and thickness caused by extracellular matrix (ECM) remodeling. However, the identities of the initiators and signaling pathways that induce scleral ECM remodeling in myopia are unknown. Here, we used single-cell RNA-sequencing to identify pathways activated in the sclera during myopia development. We found that the hypoxia-signaling, the eIF2-signaling, and mTOR-signaling pathways were activated in murine myopic sclera. Consistent with the role of hypoxic pathways in mouse model of myopia, nearly one third of human myopia risk genes from the genome-wide association study and linkage analyses interact with genes in the hypoxia-inducible factor-1α (HIF-1α)-signaling pathway. Furthermore, experimental myopia selectively induced HIF-1α up-regulation in the myopic sclera of both mice and guinea pigs. Additionally, hypoxia exposure (5% O2) promoted myofibroblast transdifferentiation with down-regulation of type I collagen in human scleral fibroblasts. Importantly, the antihypoxia drugs salidroside and formononetin down-regulated HIF-1α expression as well as the phosphorylation levels of eIF2α and mTOR, slowing experimental myopia progression without affecting normal ocular growth in guinea pigs. Furthermore, eIF2α phosphorylation inhibition suppressed experimental myopia, whereas mTOR phosphorylation induced myopia in normal mice. Collectively, these findings defined an essential role of hypoxia in scleral ECM remodeling and myopia development, suggesting a therapeutic approach to control myopia by ameliorating hypoxia.

Transcriptional profiling of the chick retina identifies down-regulation of VIP and UTS2B genes during early lens-induced myopia.

Gene expression of the chick retina was examined during the early development of lens-induced myopia (LIM) using whole transcriptome sequencing. Monocular treatment of the right eyes with -10 diopter (D) lenses was performed on newly born chicks for one day (LIM-24) or two days (LIM-48), while the contralateral eyes without lenses served as controls. Myopia development was confirmed by demonstrating significant elongation of the optical axis in lens-treated eyes compared to untreated control eyes. RNA was extracted and RNA-seq was performed using the Illumina HiSeqTM 2000 platform. Data analysis was carried out on a Partek® Flow platform. Using screening criteria of ≥1.30-fold change and a false discovery rate <1%, 11 (five down-regulated and six up-regulated) and 35 differentially expressed genes (six down-regulated and twenty-nine up-regulated) were identified at 24 hours and 48 hours, respectively. Using another cohort for validation, Quantitative PCR confirmed significant changes in the expression of VIP and UTS2B mRNA (P <0.05) after only 24 hours of LIM treatment and numerical changes in the expression for PCGF5 and FOXG1, which were consistent with transcriptome sequencing but did not reach statistical significance. These data suggest that concerted changes of retinal gene expression may be instrumental in the initiation of axial elongation and myopia development.

The Tyrosine Kinase-Driven Networks of Novel Long Non-coding RNAs and Their Molecular Targets in Myeloproliferative Neoplasms.

Recent research has focused on the mechanisms by which long non-coding RNAs (lncRNAs) modulate diverse cellular processes such as tumorigenesis. However, the functional characteristics of these non-coding elements in the genome are poorly understood at present. In this study, we have explored several mechanisms that involve the novel lncRNA and microRNA (miRNA) axis participating in modulation of drug response and the tumor microenvironment of myeloproliferative neoplasms (MPNs). We identified novel lncRNAs via mRNA sequencing that was applied to leukemic cell lines derived from BCR-ABL1-positive and JAK2-mutant MPNs under treatment with therapeutic tyrosine kinase inhibitors (TKI). The expression and sequence of novel LNC000093 were further validated in both leukemic cells and normal primary and pluripotent cells isolated from human blood, including samples from patients with chronic myelogenous leukemia (CML). Downregulation of LNC000093 was validated in TKI-resistant CML while a converse expression pattern was observed in blood cells isolated from TKI-sensitive CML cases. In addition to BCR-ABL1-positive CML cells, the driver mutation JAK2-V617F-regulated lncRNA BANCR axis was further identified in BCR-ABL1-negative MPNs. Further genome-wide validation using MPN patient specimens identified 23 unique copy number variants including the 7 differentially expressed lncRNAs from our database. The newly identified LNC000093 served as a competitive endogenous RNA for miR-675-5p and reversed the imatinib resistance in CML cells through regulating RUNX1 expression. The extrinsic function of LNC000093 in exosomal H19/miR-675-induced modulation for the microenvironment was also determined with significant effect on VEGF expression.

Viral MicroRNAs Encoded by Nucleocapsid Gene of SARS-CoV-2 Are Detected during Infection, and Targeting Metabolic Pathways in Host Cells.

MicroRNAs (miRNAs) are critical regulators of gene expression that may be used to identify the pathological pathways influenced by disease and cellular interactions. Viral miRNAs (v-miRNAs) encoded by both DNA and RNA viruses induce immune dysregulation, virus production, and disease pathogenesis. Given the absence of effective treatment and the prevalence of highly infective SARS-CoV-2 strains, improved understanding of viral-associated miRNAs could provide novel mechanistic insights into the pathogenesis of COVID-19. In this study, SARS-CoV-2 v-miRNAs were identified by deep sequencing in infected Calu-3 and Vero E6 cell lines. Among the ~0.1% small RNA sequences mapped to the SARS-CoV-2 genome, the top ten SARS-CoV-2 v-miRNAs (including three encoded by the N gene; v-miRNA-N) were selected. After initial screening of conserved v-miRNA-N-28612, which was identified in both SARS-CoV and SARS-CoV-2, its expression was shown to be positively associated with viral load in COVID-19 patients. Further in silico analysis and synthetic-mimic transfection of validated SARS-CoV-2 v-miRNAs revealed novel functional targets and associations with mechanisms of cellular metabolism and biosynthesis. Our findings support the development of v-miRNA-based biomarkers and therapeutic strategies based on improved understanding of the pathophysiology of COVID-19.

The myopia susceptibility locus vasoactive intestinal peptide receptor 2 (VIPR2) contains variants with opposite effects.

Myopia is the commonest eye disorder in the world. High myopes are predisposed to ocular pathologies. The vasoactive intestinal peptide receptor 2 (VIPR2) gene was identified as a myopia susceptibility locus by our group and another group. We continued to fine-map this locus. A case-control study was performed in 4 sequential stages with a total of 941 highly myopic subjects and 846 control subjects, all unrelated Chinese. Stage 1 experimentally genotyped 64.4% of the entire cohort for 152 single-nucleotide polymorphisms (SNPs) and Stage 2 the remaining subjects for 21 SNPs. Stage 3 combined the genotypes for 21 SNPs for the entire cohort, and identified one group of high-risk haplotypes and one group of protective haplotypes significantly associated with high myopia. Stage 4 imputed genotypes for variants in the VIPR2 region and identified two independent groups of variants: one group with high-risk minor alleles and another with protective minor alleles. Variants within each group were generally in strong linkage disequilibrium among themselves while high-risk variants were in linkage equilibrium with protective variants. Therefore, the VIPR2 locus seems to contain variants with opposite effects. This is the first study that has examined the genetic architecture of a myopia susceptibility locus in detail.