LncRNA GAS5-hnRNPK axis inhibited ovarian cancer progression via inhibition of AKT signaling in ovarian cancer cells.

BACKGROUND: The incidence of ovarian cancer ranks third among gynecologic malignancies, but the mortality rate ranks first. METHODS: The expression of GAS5 is low in ovarian cancer and is associated with the low survival of ovarian cancer patients according to public ovarian cancer databases. GAS5 overexpression inhibited ovarian malignancy by affecting the proliferation and migratory abilities in OVCAR3 and A2780 cells. GAS5 overexpression increased the rate of cell apoptosis, and the cells were blocked in the G1 phase as assessed by flow cytometry. RESULTS: We found that hnRNPK was a potential target gene, which was regulated negatively by GAS5 based on RNA-pulldown and mass spectrometry analysis. Mechanistically, GAS5 affected the inhibition of the PI3K/AKT/mTOR pathways and bound the protein of hnRNPK, which influenced hnRNPK stability. Furthermore, rescue assays demonstrated hnRNPK was significantly involved in the progression of ovarian cancer. CONCLUSIONS: Our study showed one of the mechanisms that GAS5 inhibited ovarian cancer metastasis by down-regulating hnRNPK expression, and GAS5 can be used to predict the prognosis of ovarian cancer patients.

Parasite reliance on its host gut microbiota for nutrition and survival.

Studying the microbial symbionts of eukaryotic hosts has revealed a range of interactions that benefit host biology. Most eukaryotes are also infected by parasites that adversely affect host biology for their own benefit. However, it is largely unclear whether the ability of parasites to develop in hosts also depends on host-associated symbionts, e.g., the gut microbiota. Here, we studied the parasitic wasp Leptopilina boulardi (Lb) and its host Drosophila melanogaster. Results showed that Lb successfully develops in conventional hosts (CN) with a gut microbiota but fails to develop in axenic hosts (AX) without a gut microbiota. We determined that developing Lb larvae consume fat body cells that store lipids. We also determined that much larger amounts of lipid accumulate in fat body cells of parasitized CN hosts than parasitized AX hosts. CN hosts parasitized by Lb exhibited large increases in the abundance of the bacterium Acetobacter pomorum in the gut, but did not affect the abundance of Lactobacillus fructivorans which is another common member of the host gut microbiota. However, AX hosts inoculated with A. pomorum and/or L. fructivorans did not rescue development of Lb. In contrast, AX larvae inoculated with A. pomorum plus other identified gut community members including a Bacillus sp. substantially rescued Lb development. Rescue was further associated with increased lipid accumulation in host fat body cells. Insulin-like peptides increased in brain neurosecretory cells of parasitized CN larvae. Lipid accumulation in the fat body of CN hosts was further associated with reduced Bmm lipase activity mediated by insulin/insulin-like growth factor signaling (IIS). Altogether, our results identify a previously unknown role for the gut microbiota in defining host permissiveness for a parasite. Our findings also identify a new paradigm for parasite manipulation of host metabolism that depends on insulin signaling and the gut microbiota.

Two novel venom proteins underlie divergent parasitic strategies between a generalist and a specialist parasite.

Parasitoids are ubiquitous in natural ecosystems. Parasitic strategies are highly diverse among parasitoid species, yet their underlying genetic bases are poorly understood. Here, we focus on the divergent adaptation of a specialist and a generalist drosophilid parasitoids. We find that a novel protein (Lar) enables active immune suppression by lysing the host lymph glands, eventually leading to successful parasitism by the generalist. Meanwhile, another novel protein (Warm) contributes to a passive strategy by attaching the laid eggs to the gut and other organs of the host, leading to incomplete encapsulation and helping the specialist escape the host immune response. We find that these diverse parasitic strategies both originated from lateral gene transfer, followed with duplication and specialization, and that they might contribute to the shift in host ranges between parasitoids. Our results increase our understanding of how novel gene functions originate and how they contribute to host adaptation.

The complete mitochondrial genome of Trichopria drosophilae (Hymenoptera: Diapriidae).

Trichopria drosophilae (Hymenoptera: Diapriidae) is an important pupal endoparasitoid of Drosophila species, which has been found to be an ideal biocontrol agent to D. suzukii. In this study, the complete mitochondrial genome of T. drosophilae (GeneBank accession number: MN966974) was sequenced using Illumina HiSeq X Ten system. The mitochondrial genome is 16,375 bp long and comprises 13 protein-coding genes, 22 transfer RNA genes and 2 ribosomal RNA genes. Among them, 24 genes are in majority strand, while the others are in minority strand. The nucleotide composition of A, G, C, T is 44.9%, 6.4%, 5.6%, 43.2% respectively. We also performed a phylogenetic analysis with other known mitochondrial genomes within four families that have been shown to parasitize drosophilid species. The result shows that T. drosophilae is closely related to Ismarus sp.

The developmental transcriptome of Trichopria drosophilae (Hymenoptera: Diapriidae) and insights into cuticular protein genes.

The pupal endoparasitoid wasp Trichopria drosophilae (Hymenoptera: Diapriidae) plays an important role in biological control of many frugivorous fruit fly species including Drosophila suzukii, a well-known invasive pest. Here, we report the transcriptomes of T. drosophilae among different developmental stages. A total of 601,148,438 high-quality reads were obtained and de novo assembled into 187,704 unigenes with an average length of 1096 bp. Among them, 21,735 unigenes were annotated into 52 Gene Ontology terms and 36,898 were assigned to 25 Cluster of Orthologous Groups categories, whereas 30,585 unigenes were mapped to 270 Kyoto Encyclopedia of Genes and Genomes different pathways. Numbers of differentially expressed genes were found through comparisons between different developmental stages. We further identified 137 cuticular protein genes (CPs) from T. drosophilae transcriptome, including 59 from CPR family, 2 from Tweedle family, 1 from CPF family, 46 from CPAP family, and 29 from other CP families. We analyzed expression patterns of the CPs at different developmental stages of T. drosophilae, and found some stage-specific CPs. Quantitative real-time PCR results confirmed RNA sequencing findings based on the relative expression levels of eight randomly selected CPs. This study provides a valuable transcriptomic resource for a comprehensive understanding of the development and physiology of T. drosophilae, and will help to improve their parasitism efficiency for biological control purposes.