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Circular RNAs (circRNAs) are products of alternative splicing with roles as competitive endogenous RNAs or microRNA sponges, regulating gene expression and biological processes. However, the involvement of circRNAs in herpes simplex keratitis remains largely unexplored. This study examines circRNA and miRNA expression profiles in primary human corneal epithelial cells infected with HSV-1, compared to uninfected controls, using microarray analysis. Bioinformatic analysis predicted the potential function of the dysregulated circRNAs and microRNA response elements (MREs) in these circRNAs, forming an interaction network between dysregulated circRNAs and miRNAs. A total of 332 circRNAs and 16 miRNAs were upregulated, while 80 circRNAs and six miRNAs were downregulated (fold change ≥2.0 and p < 0.05). Gene ontology (GO) and KEGG pathway analyses were performed on parental genes of dysregulated circRNAs to uncover potential functions in HSV-1 infection. Notably, miR-181b-5p, miR-338-3p, miR-635, and miR-222-3p emerged as pivotal miRNAs interacting with multiple dysregulated circRNAs. This comprehensive study offers insights into differentially expressed circRNAs and miRNAs during HSV-1 infection in corneal epithelial cells, shedding light on circRNA-miRNA interactions' potential role in herpes simplex keratitis pathogenesis. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) regulate post-transcription gene expression by targeting genes and play crucial roles in diverse biological processes involving body color formation. However, miRNAs and miRNA-targets underlying shell color polymorphism remain largely unknown in mollusca. Using four shell colors full-sib families of the Pacific oyster Crassostrea gigas, we systematically identified miRNAs and miRNA-targets in the mantles, which organ could produce white, golden, black or partially pigmented shell. RNA sequencing and analysis identified a total of 53 known miRNA and 91 novel miRNAs, 47 of which were detected to differentially express among six pairwise groups. By integrating miRNA and mRNA expression profiles, a total of 870 genes were predicted as targets of differentially expressed miRNAs, mainly involving in biomineralization and pigmentation through functional enrichment. Furthermore, a total of four miRNAs and their target mRNAs were predicted to involve in synthesis of melanin, carotenoid or tetrapyrrole. Of them, lgi-miR-317 and its targets peroxidase and lncRNA TCONS_00951105 are implicated in acting as the competing endogenous RNA to regulate melanogenesis. Our studies revealed the systematic characterization of miRNAs profiles expressed in oyster mantle, which might facilitate understanding the intricate molecular regulation of shell color polymorphism and provide new insights into breeding research in oyster. [ABSTRACT FROM AUTHOR]

Ischemic preconditioning and ischemic postconditioning (IPostC) represent promising strategies to reduce ischemia-reperfusion (I/R) injury and attenuate the lethal ischemic damage following stroke. However, the mechanism underlying this attenuation remains to be elucidated. It was hypothesized that alterations in microRNA (miRNA) expression in the cerebral cortex and hippocampus of mice following I/R is associated with the functional improvement induced by IPostC. Behavioral changes were assessed in a mouse model of I/R in the absence or presence of IPostC, followed by microarray analyses to investigate the expressional alterations of miRNAs in the cerebral cortex and hippocampus of mice. The results of the present study revealed that IPostC abrogated the neurological impairment and hippocampus-associated cognitive deficits induced by I/R, and upregulated or downregulated the expression levels of numerous miRNAs. Furthermore, the upregulation of miR-19a, and the downregulation of miR-1, let-7f and miR-124 expression levels following IPostC was confirmed utilizing reverse transcription-quantitative polymerase chain reaction. The results of the present study demonstrated that alterations in miRNA expression in the cerebral cortex and hippocampus of mice following I/R was associated with the neuroprotection induced by IPostC. [ABSTRACT FROM AUTHOR]

Triploid oysters generate fewer gametes than diploid oysters and exhibit varying degrees of gonad development. The expression of related genes, such as those involved in gametogenesis and energy metabolism, may influence reproductive potential. In addition, microRNAs (miRNAs) are important regulators of gene expression. However, the contribution of miRNAs has not yet been assessed in sterile triploid Pacific oysters (Crassostrea gigas). We therefore obtained extensive miRNA and gene expression data to identify potentially critical miRNA-mRNA interactions that are linked to sterility in triploid C. gigas. Here, we found miR-263-x to be significantly downregulated in the gonads of sterile females. The upregulated target genes were associated with lipid droplet formation, which revealed the likely involvement of nutrient accumulation during gonadal development as regulated by miR-263-x in female sterile triploids. In males, the upregulated miRNAs (miR-1992-y and miR-2001-x) were shown to regulate spermatogenesis-related gene expression, including flagellar formation, and cell proliferation and migration. Our results suggest that energy redistribution regulated by miRNAs may be critical for gonad development in females, indicating that sterile triploids undergo a significant reduction in gamete number and show an increased accumulation of nutrients in the gonads. Our findings further indicate that decreased expression of genes related to spermatogenesis regulated by miRNAs is important in gonadal dysgenesis in sterile triploids. These results shed light on the epigenetic regulatory mechanisms governing sterility in triploid bivalves. • miRNAs played a vital role in the impaired gametogenesis of triploid Pacific oysters. • miR-263-x was associated with the regulation of lipogenesis in female triploid gonads. • Spermatogenesis-related genes were negatively regulated by miR-1992-y and miR-2001-x. [ABSTRACT FROM AUTHOR]

A number of environmental toxicants affect our health through physical, biological or chemical mechanisms. There is growing evidence indicating that microRNA (miRNA) plays an important role in toxicogenomics, disease aetiology and the effect of toxicants. This article summarises recent findings on miRNAs associated with various toxicants and those targeted in the development of therapeutics. Environmental epigenetic studies have revealed the role of miRNAs in the regulation of gene activities induced by environmental changes after exposure to toxic substances. Toxicant-induced changes in miRNA expression have a potential to be informative markers in the evaluation of toxicant risks. miRNAs are now considered to be predictive biomarkers or indicators of tissue injury due to toxicant exposure; thus, miRNAs can also be utilised as therapeutic targets. [ABSTRACT FROM AUTHOR]

One of the most important physiological process in the life cycle of most bivalves is the sexual reproduction required for species propagation. Understanding the molecular regulatory mechanisms of gender determination and gonad development have potential application in bivalve aquaculture, but there is still limited knowledge about this issue. The Pacific oyster Crassostrea gigas is a commercially important bivalve in aquaculture worldwide, as well as a representative specie to study the sexual development in bivalves for its complicated sexuality, including dioecy, sex change and rare hermaphroditism. In this study, an integrated analysis of miRNA and mRNA expression profiles of oyster gonads at different gametogenesis stages was performed to explore their possibly regulatory patterns in sexual development of C. gigas. Based on small RNA sequencing, a total of 122 miRNAs were identified, including 53 conserved and 69 novel miRNAs. Six miRNAs exhibited sex-specific pattern that expressed exclusively from either male or female gonads with increasing abundance throughout the gonadal development. Moreover, 287 putative targets of the six sex-biased miRNAs were predicted by combining previous transcriptome data. GO and KEGG enrichment analysis of target genes revealed that these sex-biased miRNAs might participate in the regulation of gametogenesis. Further, potential miRNA-mRNA interactions based on six sex-biased miRNAs were collected. The homolog of a key participator in testis development, meiotic recombination protein SPO11 in C. gigas (CgSPO11), was predicted as a target of female-biased miRNA lgi-miR-96a. This negative miRNA-mRNA expression relationship was validated in additional samples by quantitative real-time PCR (qRT-PCR) and the regulation of CgSPO11 by lgi-miR-96a was preliminarily confirmed by a dual-luciferase reporter assay. This study provides information regarding the gonad miRNAs of C. gigas and leads to the discovery of miRNA-mRNA interactions in gonad development, which will facilitate further investigations in molecular mechanisms of bivalve sex differentiation. • A total of 122 miRNAs were identified during the Pacific oyster gonad development. • Six sex-biased miRNAs might participate in the regulation of oyster gametogenesis. • The CgSPO11 gene is a target of lgi-miR-96a. [ABSTRACT FROM AUTHOR]