BackgroundMicroRNAs (miRNAs) have emerged as master regulators of angiogenesis and other cancer-related events. Discovering new angiogenesis-regulating microRNAs (angiomiRs) will eventually help in developing new therapeutic strategies for tumor angiogenesis and cardiovascular diseases. Kaposi’s sarcoma (KS), which is induced by the etiological infectious agent KS-associated herpesvirus (KSHV), is a peculiar neoplasm that expresses both blood and lymphatic endothelial markers and possesses extensive neovasculature. Using KSHV and its proteins as baits will be an efficient way to discover new angiomiRs in endothelial cells. Kaposin B is one of the latent viral genes and is expressed in all KSHV tumor cells. Since Kaposin B is a nuclear protein with no DNA-binding domain, it may regulate gene expression by incorporating itself into a transcription complex.ResultsWe demonstrated that c-Myc and Kaposin B form a transcription complex and bind to the miR-221/-222 promoter, thereby affecting their expression and anti-angiogenic ability. By small RNA sequencing (smRNA-Seq), we revealed that 72.1 % (173/240) of Kaposin B up-regulated and 46.5 % (113/243) of Kaposin B down-regulated known miRNAs were regulated by c-Myc. We also found that 77 novel miRNA were up-regulated and 28 novel miRNAs were down-regulated in cells expressing both c-Myc and Kaposin B compared with cells expressing Kaposin B only. The result was confirmed by RNA-IP-seq data.ConclusionsOur study identifies known and novel c-Myc-regulated microRNAs and reveals that a c-Myc-oriented program is coordinated by Kaposin B in KSHV-infected cells.Electronic supplementary materialThe online version of this article (doi:10.1186/s12918-015-0242-3) contains supplementary material, which is available to authorized users.

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BackgroundSUMOylation, as part of the epigenetic regulation of transcription, has been intensively studied in lower eukaryotes that contain only a single SUMO protein; however, the functions of SUMOylation during mammalian epigenetic transcriptional regulation are largely uncharacterized. Mammals express three major SUMO paralogues: SUMO-1, SUMO-2, and SUMO-3 (normally referred to as SUMO-1 and SUMO-2/3). Herpesviruses, including Kaposi’s sarcoma associated herpesvirus (KSHV), seem to have evolved mechanisms that directly or indirectly modulate the SUMO machinery in order to evade host immune surveillance, thus advancing their survival. Interestingly, KSHV encodes a SUMO E3 ligase, K-bZIP, with specificity toward SUMO-2/3 and is an excellent model for investigating the global functional differences between SUMO paralogues.ResultsWe investigated the effect of experimental herpesvirus reactivation in a KSHV infected B lymphoma cell line on genomic SUMO-1 and SUMO-2/3 binding profiles together with the potential role of chromatin SUMOylation in transcription regulation. This was carried out via high-throughput sequencing analysis. Interestingly, chromatin immunoprecipitation sequencing (ChIP-seq) experiments showed that KSHV reactivation is accompanied by a significant increase in SUMO-2/3 modification around promoter regions, but SUMO-1 enrichment was absent. Expression profiling revealed that the SUMO-2/3 targeted genes are primarily highly transcribed genes that show no expression changes during viral reactivation. Gene ontology analysis further showed that these genes are involved in cellular immune responses and cytokine signaling. High-throughput annotation of SUMO occupancy of transcription factor binding sites (TFBS) pinpointed the presence of three master regulators of immune responses, IRF-1, IRF-2, and IRF-7, as potential SUMO-2/3 targeted transcriptional factors after KSHV reactivation.ConclusionOur study is the first to identify differential genome-wide SUMO modifications between SUMO paralogues during herpesvirus reactivation. Our findings indicate that SUMO-2/3 modification near protein-coding gene promoters occurs in order to maintain host immune-related gene unaltered during viral reactivation.

Intracellular protein delivery enables selective regulation of cellular metabolism, signaling, and development through introduction of defined protein quantities into the cell. Most applications require that the delivered protein has access to the cytosol, either for protein activity or as a gateway to other organelles such as the nucleus. The vast majority of delivery vehicles employ an endosomal pathway however, and efficient release of entrapped protein cargo from the endosome remains a challenge. Recent research has made significant advances toward efficient cytosolic delivery of proteins using polymers, but the influence of polymer architecture on protein delivery is yet to be investigated. Here, we developed a family of dendronized polymers that enable systematic alterations of charge density and structure. We demonstrate that while modulation of surface functionality has a significant effect on overall delivery efficiency, the endosomal release rate can be highly regulated by manipulating polymer architecture. Notably, we show that large, multivalent structures cause slower sustained release, while rigid spherical structures result in rapid burst release.

BackgroundThe aims of this study were to investigate the image quality and radiation exposure of pediatric protocols for cardiac CT angiography (CTA) in infants under one year of age.Methodology/Principal FindingsCardiac CTA examinations were performed using an anthropomorphic phantom representing a 1-year-old child scanned with non-electrocardiogram-gated (NG), retrospectively electrocardiogram-gated helical (RGH) and prospectively electrocardiogram-gated axial (PGA) techniques in 64-slice and 256-slice CT scanners. The thermoluminescent dosimeters (TLD) were used for direct organ dose measurement, while dose-length product and effective mAs were also used to estimate the patient dose. For image quality, noise and signal-to-noise-ratio (SNR) were assessed based on regions-of-interest drawn on the reconstructed CT images, and were compared with the proposed cardiac image quantum index (CIQI). Estimated dose results were in accordant to the measured doses. The NG scan showed the best image quality in terms of noise and SNR. The PGA scan had better image quality than the RGH scan with 83.70% dose reduction. Noise and SNR were also corresponded to the proposed CIQI.Conclusions/SignificanceThe PGA scan protocol was a good choice in balancing radiation exposure and image quality for infant cardiac CTA. We also suggested that the effective mAs and the CIQI were suitable in assessing the tradeoffs between radiation dose and image quality for cardiac CTA in infants. These results are useful for future implementation of dose reduction strategies in pediatric cardiac CTA protocols.

Anti‐bacterial autophagy, known as xenophagy, is a host innate immune response that targets invading pathogens for degradation. Some intracellular bacteria, such as the enteric pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium), utilize effector proteins to interfere with autophagy. One such S. Typhimurium effector, SopF, inhibits recruitment of ATG16L1 to damaged Salmonella‐containing vacuoles (SCVs), thereby inhibiting the host xenophagic response. SopF is also required to maintain the integrity of the SCV during the early stages of infection. Here we show disruption of the SopF‐ATG16L1 interaction leads to an increased proportion of cytosolic S. Typhimurium. Furthermore, SopF was utilized as a molecular tool to examine the requirement for ATG16L1 in the intracellular lifestyle of Coxiella burnetii, a bacterium that requires a functional autophagy pathway to replicate efficiently and form a single, spacious vacuole called the Coxiella‐containing vacuole (CCV). ATG16L1 is required for CCV expansion and fusion but does not influence C. burnetii replication. In contrast, SopF did not affect CCV formation or replication, demonstrating that the contribution of ATG16L1 to CCV biogenesis is via its role in autophagy, not xenophagy. This study highlights the diverse capabilities of bacterial effector proteins to dissect the molecular details of host–pathogen interactions.

To report our experience with targeted-ultrasound in assessing 142 cases with clustered microcalcifications of intermediate concern detected on digital mammography. All cases had histopathologically-proven microcalcifications within the biopsied or surgical specimens. There were 30%[43/142] breast cancers and 70%[99/142] benign lesions. Only 26%[37/142] of clustered microcalcifications were identified on targeted-ultrasound and other findings including negative study (n = 33), anechoic ducts or cysts (n = 70), dilated ducts with echogenic content (n = 13) and hypoechoic nodules (n = 26). There was no statistical difference of the frequency of negative ultrasound between benign and malignant microcalcifications (P = 0.071). However, only 7.1%[5/70] cases with anechoic ducts or cysts were proven to be breast cancer. The frequencies of depiction of dilated ducts with echogenic foci or hypoechoic nodules were significantly higher for malignant microcalcifications (P < 0.001). Ultrasound was significantly more sensitive for the identification of malignant cases but biopsy of clustered microcalcifications is still warranted when targeted-ultrasound revealed negative findings.

The zoonotic bacterial pathogen Coxiella burnetii is the causative agent of Q fever, a febrile illness which can cause a serious chronic infection. C. burnetii is a unique intracellular bacterium which replicates within host lysosome-derived vacuoles. The ability of C. burnetii to replicate within this normally hostile compartment is dependent on the activity of the Dot/Icm type 4B secretion system. In a previous study, a transposon mutagenesis screen suggested that the disruption of the gene encoding the novel protein CBU2072 rendered C. burnetii incapable of intracellular replication. This protein, subsequently named EirA (essential for intracellular replication A), is indispensable for intracellular replication and virulence, as demonstrated by infection of human cell lines and in vivo infection of Galleria mellonella. The putative N-terminal signal peptide is essential for protein function but is not required for localization of EirA to the bacterial inner membrane compartment and axenic culture supernatant. In the absence of EirA, C. burnetii remains viable but nonreplicative within the host phagolysosome, as coinfection with C. burnetii expressing native EirA rescues the replicative defect in the mutant strain. In addition, while the bacterial ultrastructure appears to be intact, there is an altered metabolic profile shift in the absence of EirA, suggesting that EirA may impact overall metabolism. Most strikingly, in the absence of EirA, Dot/Icm effector translocation was inhibited even when EirA-deficient C. burnetii replicated in the wild type (WT)-supported Coxiella containing vacuoles. EirA may therefore have a novel role in the control of Dot/Icm activity and represent an important new therapeutic target.