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Circular RNAs (circRNAs) act as essential regulators in many biological processes, especially in mammalian immune response. Nonetheless, the functions and mechanisms of circRNAs in the invertebrate immune system are largely unclarified. In our previous work, 261 differentially expressed circRNAs potentially related to the development of Apostichopus japonicus skin ulceration syndrome (SUS), which is a major problem restricting the sea cucumber breeding industry, were identified by genome-wide screening. In this study, via miRanda analysis, both circRNA75 and circrRNA72 were shown to share the miR-200 binding site, a key microRNA in the SUS. The two circRNAs were verified to be increased significantly in LPS-exposed primary coelomocytes, similar to the results of circRNA-seq in sea cucumber under Vibrio splendidus-challenged conditions. A dual-luciferase assay indicated that both circRNA75 and circRNA72 could bind miR-200 in vivo, in which circRNA75 had four binding sites of miR-200 and only one for circRNA72. Furthermore, we found that miR-200 could bind the 3’-UTR of Toll interacting protein (Tollip) to negatively mediate the expression of Tollip. Silencing Tollip increased primary coelomocyte apoptosis. Consistently, inference of circRNA75 and circRNA72 could also downregulate Tollip expression, thereby increasing the apoptosis of primary coelomocytes, which could be blocked by miR-200 inhibitor treatment. Moreover, the rate of si-circRNA75-downregulated Tollip expression was higher than that of si-circRNA72 under an equivalent amount. CircRNA75 and circRNA72 suppressed coelomocyte apoptosis by sponging miR-200 to promote Tollip expression. The ability of circRNA to adsorb miRNA might be positively related to the number of binding sites for miRNA.

Circular RNAs (circRNAs) were recently recognized to act as competing endogenous RNAs and play roles in gene expression regulation. Previous studies in humans and silkworms have shown that circRNAs take part in immune regulation. Here, we conducted coelomocyte circRNA sequencing to explore its immune functions in healthy and skin ulceration syndrome (SUS)-diseased sea cucumbers. A total of 3,592 circRNAs were identified in libraries with diversified circularization patterns compared with animal models. The common intron-pairing-driven circularization models are not popular in sea cucumber genome, which was replaced with intergenic region circularization. The accuracy of these identified circRNAs was further validated by Sanger sequencing and RNase R-treated assays. Expression profile analysis indicated that 117 circRNAs were upregulated and 144 circRNAs were downregulated in SUS-diseased condition, of which 71.6% were intergenic-type circRNAs. The interaction network of differentially expressed circRNAs and microRNAs (miRNAs) was constructed and showed that miR-2008 and miR-31, detected with significantly differential expression in SUS-affected samples in a previous study, were predicted to be regulated by 10 and 11 differentially expressed circRNAs with more than 10 binding sites, respectively. Moreover, seven circRNAs were further validated by quantitative real-time PCR, whose variation trends were consistent with circRNA sequencing. All our results supported that intergenic-type circRNAs might have a dominant function in Apostichopus japonicas immune response by acting as miRNA regulators.

Lectins exist widely in marine bioresources such as bacteria, algae, invertebrate animals and fishes. Some purified marine lectins have been found to elicit cytotoxicity to cancer cells. However, there are few reports describing the cytotoxic effect of marine lectins on cancer cells through virus-mediated gene delivery. We show here that a replication-deficient adenovirus-carrying gene encoding Haliotis discus discus sialic acid binding lectin (Ad.FLAG-HddSBL) suppressed cancer cell proliferation by inducing apoptosis, as compared to the control virus Ad.FLAG. A down-regulated level of anti-apoptosis factor Bcl-2 was suggested to be responsible for the apoptosis induced by Ad.FLAG-HddSBL infection. Further subcellular localization studies revealed that HddSBL distributed in cell membrane, ER, and the nucleus, but not in mitochondria and Golgi apparatus. In contrast, a previously reported mannose-binding lectin Pinellia pedatisecta agglutinin entered the nucleus as well, but did not distribute in inner membrane systems, suggesting differed intracellular sialylation and mannosylation, which may provide different targets for lectin binding. Further cancer-specific controlling of HddSBL expression and animal studies may help to provide insights into a novel way of anti-cancer marine lectin gene therapy. Lectins may provide a reservoir of anti-cancer genes.

Computer vision has been developed greatly in the past several years, and many useful and interesting technologies have been presented and widely applied. Image matching is an important technology based on similarity measurement. In this paper, we propose a novel feature describing model based on scale space and local principle component analysis for heterogeneous image matching. The traditional uniform eight-direction statistics is updated by a task-related k-direction statistics based on prior information of the keypoints. In addition, the k directions are determined by an approximately solution of a Min-Max problem. The principle component analysis is introduced to compute the main directions of local patches based on the gradient field. In addition, the describing vector is formed by then implementing PCA on each sub-patch of a 4 × 4 mesh. Experimental results show the accuracy and efficiency of proposed method.

Many techniques have been developed for computer vision in the past years. Features extraction and matching are the basis of many high-level applications. In this paper, we propose a multi-level features extraction for discontinuous target tracking in remote sensing image monitoring. The features of the reference image are pre-extracted at different levels. The first-level features are used to roughly check the candidate targets and other levels are used for refined matching. With Gaussian weight function introduced, the support of matching features is accumulated to make a final decision. Adaptive neighborhood and principal component analysis are used to improve the description of the feature. Experimental results verify the efficiency and accuracy of the proposed method.

The article presents a research report on an ultrasound-driven immune-boosting molecular machine for systemic tumor suppression. Topics include exploring facile and effective therapeutic modalities for synergistically controlling primary tumor and metastasis remains a pressing clinical need; and Sonodynamic therapy (SDT) offers possibility of noninvasively eradicating local solid tumors, but lacks antimetastatic activity because of its limited ability in generating systemic antitumor effect.

Therapeutic antibodies that target T-cell co-inhibitory molecules display potent antitumor effects in multiple types of cancer. LSECtin is a cell surface lectin of the DC-SIGN family expressed in dendritic cells that inhibits T-cell responses. LSECtin limits T-cell activity in infectious disease, but it has not been studied in cancer. Here we report the finding that LSECtin is expressed commonly in melanomas where it blunts tumor-specific T-cell responses. When expressed in B16 melanoma cells, LSECtin promoted tumor growth, whereas its blockade slowed tumor growth in either wild-type or LSECtin-deficient mice. The tumor-promoting effects of LSECtin were abrogated in Rag1-1- mice or in response to CD4+ or CD8+ T-cell depletion. Mechanistic investigations determined that LSECtin inhibited the proliferation of tumor-specific effector T cells by downregulating the cell cycle kinases CDK2, CDK4, and CDK6. Accordingly, as expressed in B16, tumor cells LSECtin inhibited tumorspecific T-cell responses relying upon proliferation in vitro and in vivo. Notably, LSECtin interacted with the coregulatory molecule LAG-3, the blockade of which restored IFNg secretion that was reduced by melanomaderived expression of LSECtin. Together, our findings reveal that common expression of LSECtin in melanoma cells engenders a mechanism of immune escape, with implications for novel immunotherapeutic combination strategies. [ABSTRACT FROM AUTHOR]