Description: PAF complex is an evolutionarily conserved transcriptional complex that associates with RNA polymerase II in the coding region of actively transcribing genes. Although its transcriptional activity is closely related to diverse cellular processes, such as cell-cycle progression or development in mammals, its role in immune responses has not been addressed yet. In this study, we show that CTR9, a component of PAF complex, functions as a repressor of Th17 differentiation. Both mRNA and protein levels of CTR9 were significantly decreased during the differentiation processes of naive T into Th17 effector cells. When CTR9 was depleted, IL-17 expression was induced and differentiation into Th17 cells enhanced. In naive T cells, CTR9 occupied the coding region of Il17a , but dissociated under Th17 in vitro-polarizing conditions. In contrast, both CDC73 and PAF1 were recruited to the Il17a locus under Th17-differentiation conditions. In the IL-6–stimulated splenocytes, expression of CTR9 was decreased, and chromatin-bound CTR9 disappeared in the coding region of Il17a . IL-6 also directly repressed expression of CTR9 gene, as promoter activity of CTR9 was similarly repressed by IL-6 treatment. Moreover, in mice with collagen-induced arthritis, lentivirus-mediated CTR9 overexpression in the joints ameliorated arthritis severity, decreasing the frequency of CD4 + IL-17 + T cells in lymph nodes. In conclusion, our data propose a novel feed-forward loop of IL-17 transcriptional regulatory circuit, via IL-6–mediated repression of CTR9 which is a transcriptional repressor of IL-17.

Description: The proper trafficking and localization of Toll-like receptors (TLRs) are important for specific ligand recognition and efficient signal transduction. The TLRs sensing bacterial membrane components are expressed on the cell surface and recruit signaling adaptors to the plasma membrane upon stimulation. On the contrary, the nucleotide-sensing TLRs are mostly found...

Description: Background The association between the location and the mechanism of a stroke lesion remains unclear. A diffusion-weighted imaging study may help resolve this lack of clarity. Methods and Results We studied a consecutive series of 2702 acute ischemic stroke patients whose stroke lesions were confirmed by diffusion-weighted imaging and who underwent a thorough etiological investigation. The vascular territory in which an ischemic lesion was situated was identified using standard anatomic maps of the dominant arterial territories. Stroke subtype was based on the Trial of ORG 10172 in Acute Stroke Treatment, or TOAST, classification. Large-artery atherosclerosis (37.3%) was the most common stroke subtype, and middle cerebral artery (49.6%) was the most frequently involved territory. Large-artery atherosclerosis was the most common subtype for anterior cerebral, middle cerebral, vertebral, and anterior and posterior inferior cerebellar artery territory infarctions. Small vessel occlusion was the leading subtype in basilar and posterior cerebral artery territories. Cardioembolism was the leading cause in superior cerebellar artery territory. Compared with carotid territory stroke, vertebrobasilar territory stroke was more likely to be caused by small vessel occlusion (21.4% versus 30.1%, P 〈0.001) and less likely to be caused by cardioembolism (23.2% versus 13.8%, P 〈0.001). Multiple-vascular-territory infarction was frequently caused by cardioembolism (44.2%) in carotid territory and by large-artery atherosclerosis (52.1%) in vertebrobasilar territory. Conclusions Information on vascular territory of a stroke lesion may be helpful in timely investigation and accurate diagnosis of stroke etiology.

Description: Electron density in a gas-filled capillary plasma for laser wakefield acceleration is a crucially important parameter for successful acceleration experiment. We measured the electron density by using the interferometric method, and some important plasma parameters such as an on-axis density and a channel depth are characterized with the discharge plasma current. The results from the interferometric method are also compared with the spectroscopic measurement results using the H β line for confirming their validity, and a reasonably good argeement is found between them.

Description: Background and Purpose— Although both ends of the hemoglobin range may negatively influence clinical outcomes in acute ischemic stroke, most studies have examined the linear relationship or focused on the lower end of the range. Furthermore, it is unclear whether hemoglobin concentrations at different time points during hospitalization correlate with clinical outcomes in the same manner. Methods— We identified 2681 consecutive patients with acute ischemic stroke from a prospective stroke registry database and grouped them into hemoglobin concentration quintiles using the following 5 indices: initial, nadir, time-averaged, discharge hemoglobin, and hemoglobin drop. To examine the effect of both ends of hemoglobin range, the third quintile was selected as a reference category except for hemoglobin drop, for which the first quintile was used. As outcome variables, 3-month modified Rankin Scale as an ordinal scale and 3-month mortality were used. Results— With respect to higher modified Rankin Scale scores, the adjusted odds ratios and 95% confidence intervals of the first quintiles of initial, nadir, time-averaged, and discharge hemoglobin were 1.74 (1.31–2.31), 2.64 (2.09–3.33), 1.81 (1.42–2.30), and 1.65 (1.29–2.13), respectively. The opposite ends of these hemoglobin indices were not significantly associated. The adjusted odds ratio of the fifth quintile of hemoglobin drop (greatest hemoglobin drop) was 2.09 (1.51–2.89). The mortality analysis showed similar results except for initial hemoglobin. Conclusions— In acute ischemic stroke, poor outcome was related to the lower but not the higher end of the hemoglobin range, regardless of when and how hemoglobin concentrations were measured.

Description: Background and Purpose— A role of neural networks in the development of poststroke dementia has not been clearly established. We hypothesized that stroke-mediated disruption of subcortical cholinergic pathway or large-scale neural networks contributes to poststroke dementia. Methods— A matched case–control study was conducted in a predetermined cohort with acute ischemic stroke. Cases were defined as newly developed dementia diagnosed 〉3 months after stroke using the Korean Vascular Cognitive Impairment Harmonization Standards. Each case was matched to 2 controls for age, education, and initial stroke severity. The Cholinergic Pathways HyperIntensities Scale was applied with some modifications to characterize disruption of cholinergic pathways by acute stroke lesions. Involvement of major cortical hub locations of the default mode network, central executive network, and salience network was also investigated. Results— After matching, 38 cases and 66 matched controls were included. Cholinergic Pathways HyperIntensities Scale scores were significantly higher in cases than in controls (2.2±2.9 versus 0.9±1.4). Acute ischemic lesions affecting the default mode and central executive networks were more frequently observed in cases compared with controls (36.8% versus 7.6% and 26.3% versus 6.1%, respectively). These findings remained significant in the multiple logistic regression models adjusted for various sets of potential confounders. Lesion location analysis revealed that cases were more likely to have acute lesions in the left corona radiata, hippocampal formation, and posterior parietal cortex. Conclusions— Disruption of cholinergic pathways and major hubs of large-scale neural networks might contribute to newly developed dementia after acute ischemic stroke.

Description: Aims β2-Spectrin is an actin-binding protein that plays an important role in membrane integrity and the transforming growth factor (TGF)-β signalling pathway as an adaptor for Smads. Loss of β2-spectrin in mice ( Spnb2 –/– ) results in embryonic lethality with gastrointestinal, liver, neural, and heart abnormalities that are similar to those in Smad2 +/– Smad3 +/– mice. However, to date, the role of β2-spectrin in embryogenesis, particularly in heart development, has been poorly delineated. Here, we demonstrated that β2-spectrin is required for the survival and differentiation of cardiomyocytes, and its loss resulted in defects in heart development with failure of ventricular wall thickening. Methods and results Disruption of β2-spectrin in primary muscle cells not only inhibited TGF-β/Smad signalling, but also reduced the expression of the cardiomyocyte differentiation markers Nkx2.5, dystrophin, and α-smooth muscle actin (α-SMA). Furthermore, cytoskeletal networks of dystrophin, F-actin, and α-SMA in cardiomyocytes were disorganized upon loss of β2-spectrin. In addition, deletion of β2-spectrin in mice ( Spnb2 tm1a/tm1a ) prevented proper development of the heart in association with disintegration of dystrophin structure and markedly reduced survival. Conclusion These data suggest that β2-spectrin deficiency leads to inactivation of TGF-β/Smad signalling and contributes to dysregulation of the cell cycle, proliferation, differentiation, and the cytoskeletal network, and it leads to defective heart development. Our data demonstrate that β2-spectrin is required for proper development of the heart and that disruption of β2-spectrin is a potential underlying cause of congenital heart defects.

Description: The emergence of drug-resistant hepatitis B virus (HBV) is a major problem for antiviral treatment in chronic hepatitis B infection. In this study, we analyzed the evolution of drug-resistant mutations and characterized the effects of the rtA181T and rtI233V mutations on viral replication and drug resistance. We performed a clonal analysis of the HBV polymerase gene from serum samples during viral breakthrough treated with antiviral agents. A series of mutant clones containing rtA181T and/or rtI233V mutations were constructed and determined the effect of these mutations on the replication ability and drug resistance. An in vitro study revealed that the effect of the rtA181T mutation on viral replication and drug resistance is dependent on the mutations in the overlapping surface gene. Compared to the rtA181T surface missense mutation (rtA181T/sW172S), the introduction of rtA181T surface nonsense mutation (rtA181T/sW172*) resulted in decreased viral replication and increased drug resistance. Complementation assay revealed that the truncated PreS1 is responsible for reduced replication of rtA181T/sW172* mutant. Moreover, the rtA181T/sW172* mutant exhibited a defect in viral particle secretion. The rtI233V mutation that emerged during adefovir therapy reduced viral replication and conferred resistance to adefovir. Our data suggest that the impact of the rtA181T mutation on replication and drug resistance differs based on the mutation status of the corresponding surface gene. The rtI233V mutation also affects replication ability and drug resistance. This observation suggests the need for genotypic analysis of overlapping surface genes to manage antiviral drug resistance if clinical isolates harbor the rtA181T mutation. IMPORTANCE The emergence of drug-resistant HBV that are no longer susceptible to nucleos(t)ide analogues is a major problem for antiviral treatment in chronic hepatitis B infection. Among drug-resistant mutations, the single rtA181T mutation is known to confer cross-resistance to antiviral drugs. This mutation causes intermediate or reduced susceptibility to tenofovir. Moreover, the clinical occurrence of the rtA181T mutation during antiviral therapy is also high. Our study revealed that the effect of the rtA181T mutation on viral replication and drug resistance is dependent on the mutations in the overlapping surface gene. This observation suggests the need for genotypic analysis of overlapping surface genes to manage antiviral drug resistance if clinical isolates harbor the rtA181T mutation. We believe that our study will not only extend the understanding of the drug resistance mechanism, but it will also ultimately provide new treatment options for patients with multidrug resistant HBV.

Description: Small intestinal innate lymphoid cells (ILCs) regulate intestinal epithelial cell homeostasis and help to prevent pathogenic bacterial infections by producing IL-22. In a global gene-expression analysis comparing small intestinal ILCs (Lin – c-Kit + Sca-1 – cells) with non-ILCs (Lin – c-Kit – Sca-1 – cells), we found that Lin – c-Kit + Sca-1 – cells highly expressed the mRNAs for Il22, antimicrobial peptides, Csf2rb2 (Il3r), mast cell proteases, and Rorc. We then subdivided the Lin – c-Kit + Sca-1 – cells into three groups—Lin – c-Kit + NKp46 – CD4 – , Lin – c-Kit + NKp46 – CD4 + (CD4 + LTi-like cells), and Lin – c-Kit + NKp46 + (NKp46 + ILC22 cells)—and showed that the Lin – c-Kit + NKp46 – CD4 – cells produced the highest level of IL-22 protein after IL-1β, IL-23, or IL-1β and IL-23 stimulation. In addition, we showed that the majority of the Lin – c-Kit + NKp46 – CD4 – population was IL-7Rα + CD34 – β7 int cells, and IL-7Rα – cells could be divided into three subsets (CD34 + β7 int , CD34 – β7 int , and CD34 int β7 hi cells). The IL-7Rα + CD34 – β7 int cells strongly expressed the transcripts for Il17f and Il22 after costimulation with IL-1β and IL-23. The IL-7Rα – CD34 + β7 int and IL-7Rα – CD34 int β7 hi cells predominantly expressed the transcripts for mast cell proteases and differentiated almost entirely into mast cells after 1 wk in culture medium supplemented with a cytokine mixture, whereas the IL-7Rα – CD34 – β7 int cells highly expressed α-defensins and showed no differentiation. Taken together, these findings indicate that the IL-7Rα – CD34 + β7 int and IL-7Rα – CD34 int β7 hi populations are mast cell progenitors, and the IL-7Rα + CD34 – β7 int (CD4 – LTi-like cells) and IL-7Rα – CD34 - β7 int populations within Lin – c-Kit + NKp46 – CD4 – cells may control intestinal homeostasis and provide intestinal protection by producing high levels of IL-22 and α-defensins, respectively.

Description: Acyl-homoserine lactone–mediated quorum sensing (QS) regulates diverse activities in many species of Proteobacteria. QS-controlled genes commonly code for production of secreted or excreted public goods. The acyl-homoserine lactones are synthesized by members of the LuxI signal synthase family and are detected by cognate members of the LuxR family of transcriptional...