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BACKGROUND Long-non-coding RNA (lncRNA) SNHG15 has been reported to be an aberrantly expressed lncRNA in patients with ischemic stroke, but its role in neuronal injury following ischemic stroke remains unclear. We hypothesized that this lncRNA is associated with the pathogenesis of ischemic stroke. MATERIAL AND METHODS A mouse model of ischemic stroke was established by middle cerebral artery occlusion (MCAO). A neurogenic mouse cell line Neuro-2a (N2a) was subjected to oxygen-glucose deprivation (OGD) for in vitro experiments. Expression of SNHG15, microRNA-18a (miR-18a), and CXCL13 in mouse brain and in OGD-treated N2a cells was determined. Altered expression of SNHG15 and miR-18a was introduced to detect their roles in N2a cell viability and apoptosis. Targeting relationships between miR-18a and SNHG15 or CXCL13 were validated by luciferase assays. Cells were treated with the ERK/MEK antagonist U0126 to assess the role of the ERK/MEK signaling pathway in N2a cell growth. RESULTS SNHG15 and CXCL13 were overexpressed and miR-18a was underexpressed in MCAO-induced mice and OGD-treated N2a cells. Silencing of SNHG15 or overexpression of miR-18a promoted cell viability, while decreased cell apoptosis induced by OGD; however, subsequent disruption of the ERK/MEK signaling pathway reversed these effects. SNHG15 was found to bind to miR-18a, which could further target CXCL13. CONCLUSIONS Silencing of SNHG15 led to CXCL13 upregulation through sequestering miR-18a and the following ERK/MEK activation, thus enhancing viability while reducing apoptosis of N2a cells. SNHG15 may serve as a novel target for ischemic stroke treatment.

Objective: This study aims to investigate whether SNHG16 (small nucleolar RNA host gene 16) can promote the progression of osteoarthritis (OA) by regulating the microRNA-93-5p/Cyclin D1 (CCND1) axis, thereby finding new therapeutic targets for the treatment of OA., Patients and Methods: A total of 23 OA patients and 23 patients undergoing lower extremity amputation were enrolled in this study. We collected their cartilage tissues from knee joint for isolating chondrocytes. The relative levels of SNHG16, CCND1 and microRNA-93-5p in cartilage tissues of OA patients and controls were determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The regulatory effect of SNHG16 on proliferative potential of chondrocytes was evaluated by Cell Counting Kit-8 (CCK-8) and colony formation assay, respectively. Cell cycle progression was examined using flow cytometry. Dual-Luciferase reporter gene assay was conducted to verify the binding between SNHG16 with microRNA-93-5p and microRNA-93-5p with CCND1. Rescue experiments were performed to elucidate whether SNHG16 regulated CCND1 expression by targeting microRNA-93-5p., Results: The expressions of SNHG16 and CCND1 upregulated, while microRNA-93-5p downregulated in cartilage tissues of OA patients relative to controls. Correlation regression analyses showed a negative expression correlation between SNHG16 and microRNA-93-5p, as well as CCND1 and microRNA-93-5p in OA patients. On the contrary, SNHG16 expression was positively correlated to CCND1 expression in OA. The knockdown of SNHG16 suppressed viability, cloning ability and cell cycle progression, but induced apoptosis in chondrocytes. Dual-Luciferase reporter gene assay showed that SNHG16 could bind to microRNA-93-5p. SNHG16 knockdown markedly upregulated the expression of microRNA-93-5p. Moreover, the knockdown of microRNA-93-5p reversed the inhibited viability due to SNHG16 knockdown. Transfection of microRNA-93-5p mimics markedly inhibited CCND1 expression. Importantly, CCND1 overexpression reversed the inhibitory effect of SNHG16 knockdown on chondrocyte viability., Conclusions: SNHG16 promotes the development of OA by regulating microRNA-93-5p/CCND1 axis.

Small RNAs (sRNAs) are short noncoding RNAs that play roles in many biological processes, including drought responses in plants. However, how the expression of sRNAs dynamically changes with the gradual imposition of drought stress in plants is largely unknown. We generated time-series sRNA sequence data from maize ( L.) seedlings under drought stress (DS) and under well-watered (WW) conditions at the same time points. Analyses of length, functional annotation, and abundance of 736,372 nonredundant sRNAs from both DS and WW data, as well as genome copy numbers at the corresponding genomic regions, revealed distinct patterns of abundance and genome organization for different sRNA classes. The analysis identified 6646 sRNAs whose regulation was altered in response to drought stress. Among drought-responsive sRNAs, 1325 showed transient downregulation by the seventh day, coinciding with visible symptoms of drought stress. The profiles revealed drought-responsive microRNAs, as well as other sRNAs that originated from ribosomal RNAs (rRNAs), splicing small nuclear RNAs, and small nucleolar RNAs (snoRNA). Expression profiles of their sRNA derivers indicated that snoRNAs might play a regulatory role through regulating the stability of rRNAs and splicing small nuclear RNAs under drought condition., (Copyright © 2019 Crop Science Society of America.)

The pathobiological causes, the shared cellular and molecular pathways in catatonia and in catatonic presentation in neuropsychiatric disorders are yet to be determined. The hypotheses in this paper have been deduced from the latest scientific research findings and clinical observations of patients with genetic disorders, behavioral phenotypes and other family members suffering mental disorders. The first hypothesis postulates that catatonia and the heterogeneity of catatonic signs and symptoms involve nucleolar dysfunction arising from abnormalities of the brain-specific, non-coding micro-RNA, SNORD115 genes (either duplications or deletions) which result in pathobiological dysfunction of various combinations in the downstream pathways (possibly along with other genes in these shared pathways). SNORD115 controls five genes CRHR1, PBRM1, TAF1, DPM2, and RALGPS1 as well as the alternative splicing of serotonin 2C receptor. SNORD115 abnormalities with varying downstream multigene involvement would account for catatonia across the life span within some subtypes of autism spectrum disorders, schizophrenia, bipolar and major depressive disorder, psychosis, genetic disorders, and in immune disorders such as anti-N-methyl-d-aspartate receptor (NMDAR) antibody encephalitis as well as the susceptibility to the neuroleptic malignant syndrome (NMS) if environmentally triggered. Furthermore, SNORD115 genes may underlie a genetic vulnerability when environmental triggers result in excess serotonin producing the serotonin syndrome, a condition similar to NMS in which catatonia may occur. Dysfunction of SNORD115-PBRM1 connecting with SMARCA2 as well as other proven schizophrenia-associated genes might explain why traditionally catatonia has been classified with schizophrenia. SNORD115-TAF1 and SNORD-DPM2 dysfunction introduce possible clues to the parkinsonism and increased creatinine phosphokinase in NMS, while abnormalities of SNORD115-RALGPS1 suggest links to both anti-NMDAR encephalitis and the proven predisposing catatonic SHANK3 gene. The second hypothesis postulates that periodic catatonia (PC) on 15q15 involves abnormalities of vacuolar protein sorting 39 (VPS39), a proven de novo schizophrenic gene in this chromosomal locus and part of the HOPS complex. These will impact the autophagic and endocytic pathways, thereby lowering lysosomal degradation. VPS39 mutations may be considered also to disrupt lysosome-mitochondria tethering and transport of lipids and calcium through membrane contact sites (MCSs). To account for the periodicity in PC it is speculated that the mammalian equivalent of the vacuole and mitochondria patch (vCLAMP) would be altered by VPS39 mutations and subsequently followed by the mammalian equivalent of endoplasmic reticulum mitochondria encounter structure (ERMES) restoring mitochondrial homeostasis. Future precision psychiatry will require accurate pathophysiologically-defined psychiatric diagnoses to accelerate the discovery of specific molecular-targeted medications to improve therapeutic outcomes., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

mRNA 3' end processing is an essential step in gene expression. It is well established that canonical eukaryotic pre-mRNA 3' processing is carried out within a macromolecular machinery consisting of dozens of trans-acting proteins. However, it is unknown whether RNAs play any role in this process. Unexpectedly, we found that a subset of small nucleolar RNAs (snoRNAs) are associated with the mammalian mRNA 3' processing complex. These snoRNAs primarily interact with Fip1, a component of cleavage and polyadenylation specificity factor (CPSF). We have functionally characterized one of these snoRNAs and our results demonstrated that the U/A-rich SNORD50A inhibits mRNA 3' processing by blocking the Fip1-poly(A) site (PAS) interaction. Consistently, SNORD50A depletion altered the Fip1-RNA interaction landscape and changed the alternative polyadenylation (APA) profiles and/or transcript levels of a subset of genes. Taken together, our data revealed a novel function for snoRNAs and provided the first evidence that non-coding RNAs may play an important role in regulating mRNA 3' processing., (© The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.)

Early eukaryotic ribosome biogenesis involves large multi-protein complexes, which co-transcriptionally associate with pre-ribosomal RNA to form the small subunit processome. The precise mechanisms by which two of the largest multi-protein complexes-UtpA and UtpB-interact with nascent pre-ribosomal RNA are poorly understood. Here, we combined biochemical and structural biology approaches with ensembles of RNA-protein cross-linking data to elucidate the essential functions of both complexes. We show that UtpA contains a large composite RNA-binding site and captures the 5' end of pre-ribosomal RNA. UtpB forms an extended structure that binds early pre-ribosomal intermediates in close proximity to architectural sites such as an RNA duplex formed by the 5' ETS and U3 snoRNA as well as the 3' boundary of the 18S rRNA. Both complexes therefore act as vital RNA chaperones to initiate eukaryotic ribosome assembly.

C/D box small nucleolar RNAs (SNORDs) are small noncoding RNAs, and their best-understood function is to target the methyltransferase fibrillarin to rRNA (for example, SNORD27 performs 2'-O-methylation of A27 in 18S rRNA). Unexpectedly, we found a subset of SNORDs, including SNORD27, in soluble nuclear extract made under native conditions, where fibrillarin was not detected, indicating that a fraction of the SNORD27 RNA likely forms a protein complex different from canonical snoRNAs found in the insoluble nuclear fraction. As part of this previously unidentified complex,SNORD27 regulates the alternative splicing of the transcription factor E2F7p re-mRNA through direct RNA-RNA interaction without methylating the RNA, likely by competing with U1 small nuclear ribonucleoprotein (snRNP). Furthermore, knockdown of SNORD27 activates previously "silent" exons in several other genes through base complementarity across the entire SNORD27 sequence, not just the antisense boxes. Thus, some SNORDs likely function in both rRNA and pre-mRNA processing, which increases the repertoire of splicing regulators and links both processes.

Prader-Willi syndrome (PWS) is the predominant genetic cause of obesity in humans. Recent clinical reports have suggested that micro-deletion of the Snord116 gene cluster can lead to PWS, however, the extent of the contributions of the encoded snoRNAs is unknown. Here we show that mice lacking Snord116 globally have low birth weight, increased body weight gain, energy expenditure and hyperphagia. Consistent with this, microarray analysis of hypothalamic gene expression revealed a significant alteration in feeding related pathways that was also confirmed by in situ hybridisation. Importantly, selective deletion of Snord116 only from NPY expressing neurons mimics almost exactly the global deletion phenotype including the persistent low birth weight, increased body weight gain in early adulthood, increased energy expenditure and hyperphagia. Mechanistically, the lack of Snord116 in NPY neurons leads to the upregulation of NPY mRNA consistent with the hyperphagic phenotype and suggests a critical role of Snord116 in the control of NPY neuronal functions that might be dysregulated in PWS.

Small nucleolar RNAs (snoRNAs) are molecules located in the cell nucleolus and in Cajal bodies. Many scientific reports show that snoRNAs are not only responsible for modifications of other RNAs but also fulfill multiple other functions such as metabolic stress regulation or modulation of alternative splicing. Full-length snoRNAs as well as small RNAs derived from snoRNAs have been implied in human diseases such as cancer or Prader-Willi Syndrome. In this review we describe emerging, non-canonical roles of snoRNAs and their derivatives with the emphasis on their role in human diseases.

Non-coding RNAs (ncRNAs) have recently become increasingly important in the study of cellular metabolism and regulation such as development, proliferation, differentiation and apoptosis. However, the functions of most ncRNAs have remained largely unknown. Recently, studies have begun to characterize the aberrant regulation of ncRNAs in gastric cancer (GC) cells and tissues. These ncRNAs have a close relationship with drug resistance, and with the occurrence, development, invasion and metastasis of tumors, so they could possibly become new therapeutic targets and treatment tools for GC in the future. The present review summarized current advances in our knowledge of the roles of ncRNAs in GC., (Copyright © 2015 Elsevier B.V. All rights reserved.)