miR-183/96 plays a pivotal regulatory role in mouse photoreceptor maturation and maintenance.

MicroRNAs (miRNAs) are known to be essential for retinal maturation and functionality; however, the role of the most abundant miRNAs, the miR-183/96/182 cluster (miR-183 cluster), in photoreceptor cells remains unclear. Here we demonstrate that ablation of two components of the miR-183 cluster, miR-183 and miR-96, significantly affects photoreceptor maturation and maintenance in mice. Morphologically, early-onset dislocated cone nuclei, shortened outer segments and thinned outer nuclear layers are observed in the miR-183/96 double-knockout (DKO) mice. Abnormal photoreceptor responses, including abolished photopic electroretinography (ERG) responses and compromised scotopic ERG responses, reflect the functional changes in the degenerated retina. We further identify Slc6a6 as the cotarget of miR-183 and miR-96. The expression level of Slc6a6 is significantly higher in the DKO mice than in the wild-type mice. In contrast, Slc6a6 is down-regulated by adeno-associated virus-mediated overexpression of either miR-183 or miR-96 in wild-type mice. Remarkably, both silencing and overexpression of Slc6a6 in the retina are detrimental to the electrophysiological activity of the photoreceptors in response to dim light stimuli. We demonstrate that miR-183/96-mediated fine-tuning of Slc6a6 expression is indispensable for photoreceptor maturation and maintenance, thereby providing insight into the epigenetic regulation of photoreceptors in mice.

Emerging roles of non-coding RNAs in retinal diseases: A review.

Non-coding RNAs (ncRNAs) are key players in variety of biogenesis and biological functions. Their aberrant expression has been implicated in disease progression. NcRNAs can be divided into short ncRNAs whose subtypes are mainly microRNA (miRNA), long non-coding RNA (lncRNA) and circular RNA (circRNA). They are involved in cellular processes, including gene regulation, development and disease. The retina is a remarkably sophisticated instrument with interconnected cell types and is the primary target of many genetic diseases. In addition, in terms of retinal dyshomeostasis and inflammation, ncRNAs seems to play critical roles in many retinal diseases. Here, we provide an overview of ncRNAs in developing retina. We also review how does these ncRNAs function in various retinal diseases including animal and human models. These data indicate that ncRNAs regulate cellular processes including cell proliferation, differentiation, apoptosis and contribute to initiation and progression of retinal diseases.

Circular RNAs in human and vertebrate neural retinas.

Circular RNAs (circRNAs) belong to an endogenous class of RNA molecules with both ends covalently linked in a circle. Although their expression pattern in the mammalian brain has been well studied, the characteristics and functions of circRNAs in retinas remain unknown. To reveal the whole expression profiles of circRNAs in the neural retina, we investigated retinal RNAs of human, monkey, mouse, pig, zebrafish and tree shrew and detected thousands of circRNAs showing conservation and variation in the retinas across different vertebrate species. We further investigated one of the abundant circRNAs, circPDE4B, identified in human retina. Silencing of circPDE4B significantly inhibited the proliferation of human A549 cells. Functional assays demonstrated that circPDE4B could sponge miR-181C, thereby altering the cell phenotype. We have explored the retinal circRNA repertoires across human and different vertebrates, which provide new insights into the important role of circRNAs in the vertebrate retinas, as well as in related human diseases.

Circular Rims2 Deficiency Causes Retinal Degeneration.

Circular RNAs (circRNAs) refer to a newly recognized family of non-coding RNA with single-stranded RNAs. Despite emerging evidence indicating that circRNAs are abundantly expressed in various tissues, especially in the brain and retina, the role of circRNAs in retinal function and diseases is still largely unknown. Circular Rims2 (circRims2) is highly expressed and conserved in both the human and mouse brains. However, little is known about the expression and function of circRims2 in the retina. In the current study, the high-throughput RNA-seq analysis reveals a high expression of circRims2 in the retina. In addition, it is found that circRims2 is mainly located in plexiform layers that contain synapses between retinal neurons. Knocking down circRims2 with short hairpin RNA through subretinal adeno-associated viral (AAV) delivery in the mice leads to the decrease of the thickness of the outer and inner segment (OS/IS) layers and outer nuclear layer (ONL), and cessation of scotopic and photopic electroretinogram responses. Furthermore, the current study finds that circRims2 deficiency evokes retinal inflammation and activates the tumor necrosis factor (TNF) signaling pathway. Therefore, circRims2 may play an important role in the maintenance of retinal structure and function, and circRims2 deficiency may lead to pathogenic changes in the retina.

The Circular RNome of Developmental Retina in Mice.

Circular RNAs (circRNAs) represent a class of noncoding RNAs with a wide expression pattern, and they constitute an important layer of the genome regulatory network. To date, the expression pattern and regulatory potency of circRNAs in the retina, a key part of the central nervous system, are not yet well understood. In this study, RNAs from five stages (E18.5, P1, P7, P14, and P30) of mouse retinal development were sequenced. A total of 9,029 circRNAs were identified. Most circRNAs were expressed in different stages with a specific signature, and their expression patterns were different from those of their host linear transcripts. Some circRNAs could act as sponges for several retinal microRNAs (miRNAs). Furthermore, circTulp4 could function as a competitive endogenous RNA (ceRNA) to regulate target genes. Remarkably, silencing circTulp4 in vivo led to mice having a thin outer nuclear layer (ONL) and defective retinal function. In addition, we found that circRNAs were dysregulated at a much earlier time point than that of disease onset in a retinal degeneration model (rd8 mice). In summary, we provide the first circRNA expression atlas during retinal development and highlight a key biological role for circRNAs in retinal development and degeneration.

Therapeutic efficacy of charcoal hemoperfusion in patients with acute severe dichlorvos poisoning.

AIM: To assess the efficacy of hemoperfusion (HP) in the treatment of the patients with acute severe dichlorvos (DDVP) poisoning. METHODS: One hundred and eight patients with acute severe DDVP poisoning in the two teaching hospitals were enrolled. Sixty-seven patients were treated with HP (HP group) and forty-one patients accepted traditional treatment only as the control. Serum concentration of DDVP was determined by gas chromatography. RESULTS: The duration of coma, impaired consciousness, ICU stay, and mechanical ventilation was significantly shorter in the HP group than that in the control. The cumulative dosages (mg) of atropine required either in the first 24 h on admission (442+/-436 vs 899+/-485 in the control, P<0.01) or within the hospital (568+/-574 vs 1228+/-982 in the control, P<0.01) were markedly reduced in the HP patients. The lower incidence of mechanical ventilation required (13.4 % vs 36.6 % P<0.01), respiratory muscular paralysis (4.5 % vs 17.1 %, P<0.05) and the lower mortality of death (7.5 % vs 34.1 %, P<0.01) were observed in the HP group. HP could accelerate the recovery of suppressed cholinesterase activity. After the procedure, the DDVP level was decreased from (11+/-4) to (7+/-3) mg/L in parallel with a decline in APACHE II Score or dopamine dose and a rise in Glasgow Coma Scale (P<0.05). In addition, the mean values of peak clearance and reduction rate were (87+/-17) mL/min and 44 %+/-11 %, respectively. CONCLUSION: The rapid fall in blood DDVP level and the dramatic clinical response suggest that HP is effective in the treatment of acute severe DDVP poisoning.