Increasing evidence suggests that miRNAs play important regulatory roles in the nervous system. However, the molecular mechanisms of how specific miRNAs affect neuronal development and functions ...remain less well understood. In the present study, we provide evidence that the conserved microRNA miR-210 regulates lipid metabolism and prevents neurodegeneration in the Drosophila retina. miR-210 is specifically expressed in the photoreceptor neurons and other sensory organs. Genetic deletion of miR-210 leads to lipid droplet accumulation and photoreceptor degeneration in the retina. These effects are associated with abnormal activation of the Drosophila sterol regulatory element-binding protein signaling. We further identify the acetyl-coenzyme A synthetase (ACS) as one functionally important target of miR-210 in this context. Reduction of ACS in the miR-210 mutant background suppresses the neurodegeneration defects, suggesting that miR-210 acts through regulation of the ACS transcript. Together, these results reveal an unexpected role of miR-210 in controlling lipid metabolism and neuronal functions.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract
m
5
C is one of the longest-known RNA modifications, however, its developmental dynamics, functions, and evolution in mRNAs remain largely unknown. Here, we generate quantitative mRNA m
5
C ...maps at different stages of development in 6 vertebrate and invertebrate species and find convergent and unexpected massive methylation of maternal mRNAs mediated by NSUN2 and NSUN6. Using
Drosophila
as a model, we reveal that embryos lacking maternal mRNA m
5
C undergo cell cycle delays and fail to timely initiate maternal-to-zygotic transition, implying the functional importance of maternal mRNA m
5
C. From invertebrates to the lineage leading to humans, two waves of m
5
C regulatory innovations are observed: higher animals gain cis-directed NSUN2-mediated m
5
C sites at the 5' end of the mRNAs, accompanied by the emergence of more structured 5'UTR regions; humans gain thousands of trans-directed NSUN6-mediated m
5
C sites enriched in genes regulating the mitotic cell cycle. Collectively, our studies highlight the existence and regulatory innovations of a mechanism of early embryonic development and provide key resources for elucidating the role of mRNA m
5
C in biology and disease.
To investigate the detailed roles and mechanisms of tumor-derived exosomes in progression and metastasis of ovarian cancer in vitro.
Exosomes were isolated by differential centrifugation method; the ...morphology, size and biological markers of exosomes were separately defined by transmission electron microscopy, nanoS90 and Western blotting; Trans-well chambers assay was used to assess the ability of migration and invasion of recipient cells uptaking the exosomes from HO8910PM cells. The downstream molecule was screened by mass spectrometry.CD44 was identified by western blotting and the function of CD44 was identified by trans-well chambers assay and CCK8 assay.
Exosomes derived from HO8910PM cells could be transferred to HO8910 cells and promote cell migration and invasion in the recipient cells of ovarian cancer. And CD44 could be transferred to the HO8910 cells through exosomes from HO8910PM cells and influence the migration and invasion ability of HO8910 cells.
The more aggressive subpopulation can transfer a metastatic phenotype to the less one via secreting exosomes within a heterogeneous tumor. CD44 may be a potential therapeutic approach for ovarian cancer.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Taxol resistance in serous ovarian cancer is responsible for its poor prognosis, yet the underlying mechanism is still poorly understood. Thus, we probed the mechanism of Taxol resistance in serous ...ovarian cancer with multiple bioinformatic methods to provide novel insights into potential therapies.
The differentially expressed genes (DEGs) in Taxol-sensitive and Taxol-resistant cell lines and their relationship with the overall survival (OS) and progression-free interval (PFI) of ovarian cancer patients were analyzed using gene expression datasets from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO). The role of receptor interacting serine/threonine kinase 2 (RIPK2) was validated via identification of its coexpressed genes, functional analysis and generation of a protein-protein interaction (PPI) network. The single sample gene set enrichment analysis (ssGSEA) was used to explore immune infiltration, and genomic alterations of RIPK2 were also analyzed via cBio Cancer Genomics Portal (cBioProtal).
RIPK2 was highly expressed in Taxol resistant ovarian cancer cell lines, and its high expression was also linked with shorter OS and PFI in serous ovarian cancer patients. The PPI network analysis and pathway analysis demonstrated that RIPK2 might participate in the positive regulation of NF-κB transcription factor activity. RIPK2 expression was related to tumor microenvironment alterations, which might participate in the formation of Taxol resistance.
Our studies suggested that high expression of RIPK2 is related to Taxol resistance in serous ovarian cancer, and that RIPK2 induces Taxol resistance through NOD1/RIPK2/NF-κB inflammatory pathway activation and tumor microenvironment changes.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The dynamic process of spermatogenesis shows little variation between invertebrate models such as Drosophila, and vertebrate models such as mice and rats. In each case, germ stem cells undergo ...mitotic division to proliferate and then continue, via meiosis, through various stages of elongation and individualization from spermatogonia to spermatid to finally to form mature sperm. Mature sperm are then stored in the seminal vesicles for fertilization. Errors in any of these stages can lead to male infertility. Here, we identify that Drosophila Pif1A acts as a key regulator for sperm individualization. Loss of Pif1A leads to male sterility associated with irregular individualization complex and empty seminal vesicles without mature sperm. Pif1A is highly expressed in the testes of mated male adult flies and the Pif1A protein is expressed at a higher level in male than in female flies. Pif1A is homologous to mammalian coiled-coil domain-containing protein 157 (CCDC157), which is also enriched in the testes of humans and mice. Human CCDC157, with unknown function, was identified to be downregulated in men with idiopathic non-obstructive azoospermia (NOA). We map the function of Drosophila Pif1A during spermatogenesis, showing that Pif1A is essential for spermatide individualization and involved in the regulation of the lipid metabolism genes. Our findings might be applicable for studying the function of CCDC157 in spermatogenesis and other aspects of human male fertility.
ABSTRACT
In Drosophila, fat‐body remodeling accompanied with fat mobilization is an ecdysone‐induced dynamic process that only occurs during metamorphosis. Here, we show that the activated Drosophila ...platelet‐derived growth factor/VEGF receptor (PVR) is sufficient to induce shape changes in the fat body, from thin layers of tightly conjugated polygonal cells to clusters of disaggregated round‐shaped cells. These morphologic changes are reminiscent of those seen during early pupation upon initiation of fat‐body remodeling. Activation of PVR also triggers an early onset of lipolysis and mobilization of internal storage, as revealed by the appearance of small lipid droplets and up‐regulated lipolysis‐related genes. We found that PVR displays a dynamic expression pattern in the fat body and peaks at the larval‐prepupal transition under the control of ecdysone signaling. Removal of PVR, although it does not prevent ecdysone‐induced fat‐body remodeling, causes ecdysone signaling to be up‐regulated. Our data reveal that PVR is active in a dual‐secured mechanism that involves an ecdysone‐induced fat‐body remodeling pathway and a reinforced PVR pathway for effective lipid mobilization. Ectopic expression of activated c‐kit—the mouse homolog of PVR in the Drosophila fat body—also results in a similar phenotype. This may suggest a novel function of c‐kit as it relates to lipid metabolism in mammals.—Zheng, H., Wang, X., Guo, P., Ge, W., Yan, Q., Gao, W., Xi, Y., Yang, X. Premature remodeling of fat body and fat mobilization triggered by platelet‐derived growth factor/VEGF receptor in Drosophila. FASEB J. 31, 1964–1975 (2017). www.fasebj.org
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Mental retardation is a complex neurodevelopmental disorder. NPAT, a component of the histone locus body (HLB), has been implicated as a candidate gene for mental retardation, with a mechanism yet to ...be elucidated.
We identified that mxc, the Drosophila ortholog of NPAT, is required for the development of nervous system. Knockdown of mxc resulted in a massive loss of neurons and locomotion dysfunction in adult flies. In the mxc mutant or RNAi knockdown larval brains, the neuroblast (NB, also known as neural stem cell) cell fate is prematurely terminated and its proliferation potential is impeded concurrent with the blocking of the differentiation process of ganglion mother cells (GMCs). A reduction of transcription levels of histone genes was shown in mxc knockdown larval brains, accompanied by DNA double-strand breaks (DSBs). The subsidence of histone transcription levels leads to prematurely termination of NB cell fate and blockage of the GMC differentiation process. Our data also show that the increase in autophagy induced by mxc knockdown in NBs could be a defense mechanism in response to abnormal HLB assembly and premature termination of NB cell fate.
Our study demonstrate that Mxc plays a critical role in maintaining neural stem cell fate and GMC differentiation in the Drosophila larval brain. This discovery may shed light on the understanding of the pathogenesis of NPAT-related mental retardation in humans.
In the Drosophila larval brain, type I and type Ⅱ neuroblasts（NBs） undergo a series of asymmetric divisions which give rise to distinct progeny lineages. The intermediate neural progenitors（INPs） ...exist only in type Ⅱ NB lineages. In this study, we reveal a novel function of Inscuteable（Insc） that acts to maintain type I NB lineage identity. In insc type I NB clones of mosaic analyses with a repressible cell marker（MARCM）, the formation of extra Deadpan（Dpn）tNB-like and GMC-like cells is observed. The lack of Insc leads to the defective localization and segregation of Numb during asymmetric cell division. By the end of cytokinesis, this results in insufficient Numb in ganglion mother cells（GMCs）. The formation of extra Deadpan（Dpn）tcells in insc clones is prevented by the attenuation of Notch activity. This suggests that Insc functions through the Numb/Notch signaling pathway. We also show that in the absence of Insc in type I NB lineages, the cellular identity of GMCs is altered where they adopt an INP-like cell fate as indicated by the initiation of Dpn expression accompanied by a transient presence of Earmuff（Erm）.These INP-like cells have the capacity to divide multiple times. We conclude that Insc is necessary for the maintenance of type I NB lineage identity. Genetic manipulations to eliminate most type I NBs with overproliferating type Ⅱ NBs in the larval brain lead to altered circadian rhythms and defective phototaxis in adult flies. This indicates that the homeogenesis of NB lineages is important for the adult＇s brain function.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Epithelial ovarian cancer (EOC) is a highly prevalent disease that rapidly metastasizes and has poor prognosis. Most women are in the middle or late stages when diagnosed and have low survival rates. ...Recently, long non-coding RNAs (lncRNAs) were recognized to play pivotal roles in the development of EOC.
The expression of SLC25A21 antisense RNA 1 (SLC25A21-AS1) and Polypyrimidine Tract Binding Protein 3 (PTBP3) in EOC cells was assessed via qPCR. The proliferation activity of these cells was detected by EdU and Cell counting kit-8 (CCK8) assays, while the death rate of apoptotic cells and the cell cycle were detected by flow cytometry. Detection of cell transfer rate by transwell assay. Protein expression was measured through western blotting. Interactions between SLC25A21-AS1 and PTBP3 were detected through RNA immunoprecipitation (RIP), IF-FISH co-localization experiments and electrophoretic mobility shift assay (EMSA). The in vivo importance of SLC25A21-AS1 as a tumor suppressor modulator was assessed using murine xenograft models.
The lncRNA SLC25A21-AS1 has negligible expression in ovarian cancer tissues compared with that in normal ovarian tissues. A series of functional experiments revealed that the upregulation of SLC25A21-AS1 markedly blocked the proliferation and metastasis of EOC cells in vitro, while its downregulation had the opposite effect. Overexpression of SLC25A21-AS1 in a nude mouse model of EOC in vivo resulted in slower tumor growth and weakened metastatic potential. Moreover, SLC25A21-AS1 reduced the protein stability of PTBP3 and promoted its degradation. A series of subsequent experiments found that SLC25A21-AS1 inhibits EOC cell proliferation and metastasis by modulating PTBP3 through the ubiquitin-proteasome pathway and that the combination of SLC25A21-AS1 and PTBP3 provides the necessary conditions for the for the function to be realized.
Our research reveals the effect of SLC25A21-AS1 in EOC development and suggests SLC25A21-AS1 can serve as a prognostic target by promoting the degradation of PTBP3 to improve patient survival.
The mechanisms that regulate cytoskeletal remodeling during the transition between mitosis and interphase are poorly understood. In fission yeast the MOR pathway promotes actin polarization to cell ...tips in interphase, whereas the SIN signaling pathway drives actomyosin ring assembly and cytokinesis. We show that the SIN inhibits MOR signaling in mitosis by interfering with Nak1 kinase-mediated activation of the most downstream MOR component, the NDR family kinase Orb6. Inactivation of the MOR may be a key function of the SIN because attenuation of MOR signaling rescued the cytokinetic defects of SIN mutants and allowed weak SIN signaling to trigger ectopic cytokinesis. Furthermore, failure to inhibit the MOR is toxic when the cell division apparatus is compromised. Together, our results reveal a mutually antagonistic relationship between the SIN and MOR pathways, which is important for completion of cytokinesis and coordination of cytoskeletal remodeling at the mitosis-to-interphase transition.
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