BackgroundThyroid cancer is one of the most prevalent malignancies in endocrine system. Further understanding and revealing the molecular mechanism underlying thyroid cancer are indispensable for the development of effective diagnosis and treatments. In the present study, we attempted to provide novel basis for targeted therapy for thyroid cancer from the aspect of lncRNA-miRNA-mRNA interaction.MethodsThe expression and cellular function of XIST (X-inactive specific transcript) was determined. miRNAs which may be direct targets of XIST were screened for from online GEO database and miR-34a was selected. Next, the predicted binding between XIST and miR-34a, and the dynamic effect of XIST and miR-34a on downstream MET (hepatocyte growth factor receptor)-PI3K (phosphoinositide 3-kinase)-AKT (α-serine/threonine-protein kinase) signaling was evaluated.ResultsXIST was significantly up-regulated in thyroid cancer tissues and cell lines; XIST knockdown suppressed the cell proliferation in vivo and the tumor growth in vitro. Based on online database and online tool prediction results, miR-34a was underexpressed in thyroid cancer and might be a direct target of XIST. Herein, we confirmed the negative interaction between XIST and miR-34a; moreover, XIST knockdown could reduce the protein levels of MET, a downstream target of miR-34a, and the phosphorylation of PI3K and AKT. In thyroid cancer tissues, MET mRNA and protein levels of MET were up-regulated; MET was positively correlated with XIST while negatively correlated with miR-34a, further confirming that XIST serves as a ceRNA for miR-34a through sponging miR-34a, competing with MET for miR-34a binding, and finally modulating thyroid cancer cell proliferation and tumor growth.ConclusionIn the present study, we provided novel experimental basis for targeted therapy for thyroid cancer from the aspect of lncRNA-miRNA-mRNA interaction.Electronic supplementary materialThe online version of this article (10.1186/s13046-018-0950-9) contains supplementary material, which is available to authorized users.

Picornaviruses have evolved to hijack host cellular machinery, including the autophagic pathway. However, the mechanisms remain largely unclear. We use coxsackievirus B3 (CVB3) as a model organism to explore the possible role of picornavirus subversion of the autophagic pathway in viral infection. Our in vivo and in vitro experiments demonstrate that CVB3 infection causes a significant, albeit incomplete, inhibition of autophagic flux by limiting the fusion of autophagosomes with lysosomes and/or late endosomes. Furthermore, we show that CVB3 specifically targets SNARE protein SNAP29 and adaptor protein PLEKHM1, two critical proteins known to regulate autophagosome fusion, for cleavage through the catalytic activity of viral proteinase 3C, ultimately impairing the formation of SNARE complexes. Finally, we demonstrate that loss of SNAP29/PLEKHM1 inhibits autophagic flux, resulting in increased viral replication. Collectively, our study reveals a mechanism that supports an emerging model whereby CVB3 hijacks the autophagic machinery to facilitate its own propagation.

In this study, the effect of different dimple shapes on the tribological performance of surface texture has been investigated. First, a numerical model was developed to study the effect of dimple shapes on hydrodynamic pressure generation. The selected dimple shapes include circle, square, and ellipse, and the flow direction of lubricant is perpendicular to the major axis of elliptical dimples or the sides of square dimples. The results showed that the dimple shape can be optimized for greater hydrodynamic pressure generation. Then, the reciprocating sliding tests were carried out under oil lubrication and face-contact conditions. Tests were conducted for rotational speeds in the range 50-500 r/min and test loads of 200 and 400 N. Surface texture patterns with different dimple shapes were used, the dimple shapes and orientations were the same as those used in the numerical model, and the dimple depth and dimple area ratio were varied under fixed dimple area conditions. The test results indicated that a better friction reduction effect compared with untextured specimens can be obtained by selecting a suitable dimple area ratio and dimple depth for each dimple shape. Comparing the friction reduction effect, the elliptical dimples showed the best performance, the square dimples showed the second best results, and the circular dimples performed worst. However, as the test load increased, the friction reduction effect of all dimple shapes decreased; moreover, the differences between the shapes became smaller.

Cell autonomous immunity is the ability of individual cells to initiate a first line of host defense against invading microbes, such as viruses. Autophagy receptors, a diverse family of multivalent proteins, play a key role in this host response by detecting, sequestering, and eliminating virus in a process termed virophagy. To counteract this, positive-stranded RNA viruses, such as enteroviruses, have evolved strategies to circumvent the host autophagic machinery in an effort to promote viral propagation; however, the underlying mechanisms remain largely unclear. Here we studied the interaction between coxsackievirus B3 (CVB3) and the autophagy receptor SQSTM1 (sequestosome 1)/p62 and CALCOCO2/NDP52 (calcium binding and coiled-coil domain-containing protein 2/nuclear dot 10 protein 52). We demonstrated that SQSTM1 and CALCOCO2 differentially regulate CVB3 infection. We showed that knockdown of SQSTM1 causes increased viral protein production and elevated viral titers, whereas depletion of CALCOCO2 results in a significant inhibition of viral growth. Both receptors appear to have a role in virophagy through direct interaction with the viral capsid protein VP1 that undergoes ubiquitination during infection. Further investigation of the proviral mechanism of CALCOCO2 revealed that CALCOCO2, but not SQSTM1, suppresses the antiviral type I interferon signaling by promoting autophagy-mediated degradation of the mitochondrial antiviral signaling (MAVS) protein. Moreover, we demonstrated that viral proteinase 2A-mediated cleavage of SQSTM1 at glycine 241 impairs its capacity to associate with viral capsid, whereas cleavage of CALCOCO2 by viral proteinase 3C at glutamine 139, generates a stable C-terminal fragment that retains the proviral function of full-length CALCOCO2. Altogether, our study reveals a mechanism by which CVB3 targets selective autophagy receptors to evade host virophagy.

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We have previously demonstrated that infection by coxsackievirus B3 (CVB3), a positive-stranded RNA enterovirus, results in the accumulation of insoluble ubiquitin-protein aggregates, which resembles the common feature of neurodegenerative diseases. The importance of protein aggregation in viral pathogenesis has been recognized; however, the underlying regulatory mechanisms remain ill-defined. Transactive response DNA-binding protein-43 (TDP-43) is an RNA-binding protein that has an essential role in regulating RNA metabolism at multiple levels. Cleavage and cytoplasmic aggregation of TDP-43 serves as a major molecular marker for amyotrophic lateral sclerosis and frontotemporal lobar degeneration and contributes significantly to disease progression. In this study, we reported that TDP-43 is translocated from the nucleus to the cytoplasm during CVB3 infection through the activity of viral protease 2A, followed by the cleavage mediated by viral protease 3C. Cytoplasmic translocation of TDP-43 is accompanied by reduced solubility and increased formation of protein aggregates. The cleavage takes place at aminoacid 327 between glutamine and alanine, resulting in the generation of an N-and C-terminal cleavage fragment of~35 and~8 kDa, respectively. The C-terminal product of TDP-43 is unstable and quickly degraded through the proteasome degradation pathway, whereas the N-terminal truncation of TDP-43 acts as a dominant-negative mutant that inhibits the function of native TDP-43 in alternative RNA splicing. Lastly, we demonstrated that knockdown of TDP-43 results in an increase in viral titers, suggesting a protective role for TDP-43 in CVB3 infection. Taken together, our findings suggest a novel model by which cytoplasmic redistribution and cleavage of TDP-43 as a consequence of CVB3 infection disrupts the solubility and transcriptional activity of TDP-43. Our results also reveal a mechanism evolved by enteroviruses to support efficient viral infection. Coxsackievirus B3 (CVB3) is a small, positive-stranded RNA enterovirus. 1 The single open reading frame of CVB3 is translated into a viral polypeptide that is subsequently cleaved by two virus-encoded proteases 2A and 3C to generate structural and non-structural proteins. 2 In addition to processing viral polyprotein, 2A and 3C target host proteins important for maintenance of protein translation and transcription, antiviral activity, and cellular architecture and signaling, contributing to virus-induced pathogenesis. [3][4][5] Although enteroviral replication takes place exclusively in the cytoplasm, viral infection has been demonstrated to lead to cytoplasmic translocation of nuclear proteins. 6 For example, heterogeneous ribonucleoprotein D (hnRNP D) has been shown to translocate from the nucleus to the cytoplasm during enteroviral infection. 5,7,8 Moreover, hnRNP D is cleaved by 3C and has an antiviral function against enteroviral infection. 5,7,8 Cytoplasmic translocation after enteroviral infection has also been demonstrated for several other hnRNPs (A1, C, and K)...

KRAS mutant ( KRAS mut ) lung adenocarcinoma is a refractory cancer without available targeted therapy. The current study explored the possibility to develop coxsackievirus type B3 (CVB3) as an oncolytic agent for the treatment of KRAS mut lung adenocarcinoma. In cultured cells, we discovered that CVB3 selectively infects and lyses KRAS mut lung adenocarcinoma cells (A549, H2030, and H23), while sparing normal lung epithelial cells (primary, BEAS2B, HPL1D, and 1HAEo) and EGFR mut lung adenocarcinoma cells (HCC4006, PC9, H3255, and H1975). Using stable cells expressing a single driver mutation of either KRAS G12V or EGFR L858R in normal lung epithelial cells (HPL1D), we further showed that CVB3 specifically kills HPL1D- KRAS G12V cells with minimal harm to HPL1D- EGFR L858R and control cells. Mechanistically, we demonstrated that aberrant activation of extracellular signal-regulated kinase 1/2 (ERK1/2) and compromised type I interferon immune response in KRAS mut lung adenocarcinoma cells serve as key factors contributing to the sensitivity to CVB3-induced cytotoxicity. Lastly, we conducted in vivo xenograft studies using two immunocompromised mouse models. Our results revealed that intratumoral injection of CVB3 results in a marked tumor regression of KRAS mut lung adenocarcinoma in both non-obese diabetic (NOD) severe combined immunodeficiency (SCID) gamma (NSG) and NOD-SCID xenograft models. Together, our findings suggest that CVB3 is an excellent candidate to be further developed as a targeted therapy for KRAS mut lung adenocarcinoma.

Given the importance of the aggregation of advanced glycation end products (AGEs) and cardiac inflammation in the onset and progression of diabetic cardiomyopathy (DCM), our objective in this study was to demonstrate the cardioprotective effect of mangiferin, an antidiabetic and anti-inflammatory agent, on diabetic rat model. The DCM model was established by a high-fat diet and a low dose of streptozotocin. DCM rats were treated orally with mangiferin (20 mg/kg) for 16 weeks. Serum and left ventricular myocardium were collected for determination of inflammatory cytokines. AGEs mRNA and protein expression of nuclear factor kappa B (NF-κB) and receptor for AGEs (RAGE) in myocardium were assayed by real-time PCR and Western blot. ROS levels were measured by dihydroethidium fluorescence staining. NF-κB binding activity was assayed by TransAM NF-κB p65 ELISA kit. Chronic treatment with mangiferin decreased the levels of myocardial enzymes (CK-MB, LDH) and inflammatory mediators (TNF-α, IL-1β). Meanwhile, NF-κB is inhibited by the reduction of nuclear translocation of p65 subunit, and mangiferin reduced AGE production and decreased the mRNA and protein expression of RAGE in DCM rats. Our data indicated that mangiferin could significantly ameliorate DCM by preventing the release of inflammatory cytokines, and inhibiting ROS accumulation, AGE/RAGE production, and NF-κB nuclear translocation, suggesting that mangiferin treatment might be beneficial in DCM.