Interplay of Inflammatory, Antigen and Tissue-Derived Signals in the Development of Resident CD8 Memory T Cells

CD8 positive, tissue resident memory T cells (TRM) are a specialized subset of CD8 memory T cells that surveil tissues and provide critical first-line protection against tumors and pathogen re-infection. Recently, much effort has been dedicated to understanding the function, phenotype and development of TRM. A myriad of signals is involved in the development and maintenance of resident memory T cells in tissue. Much of the initial research focused on the roles tissue-derived signals play in the development of TRM, including TGFß and IL-33 which are critical for the upregulation of CD69 and CD103. However, more recent data suggest further roles for antigenic and pro-inflammatory cytokines. This review will focus on the interplay of pro-inflammatory, tissue and antigenic signals in the establishment of resident memory T cells

Light Curves and Period Changes of Type II Cepheids in the Globular Clusters M3 and M5

Light curves in the B, V, and I_c passbands have been obtained for the type II Cepheids V154 in M3 and V42 and V84 in M5. Alternating cycle behavior, similar to that seen among RV Tauri variables, is confirmed for V84. Old and new observations, spanning more than a century, show that V154 has increased in period while V42 has decreased in period. V84, on the other hand, has shown large, erratic changes in period that do not appear to reflect the long term evolution of V84 through the HR diagram.Comment: 28 pages, 12 figure

IKK2/NFkB signaling controls lung resident CD8+ T cell memory during influenza infection

Abstract CD8+ T cell tissue resident memory (TRM) cells are especially suited to control pathogen spread at mucosal sites. However, their maintenance in lung is short-lived. TCR-dependent NFkB signaling is crucial for T cell memory but how and when NFkB signaling modulates tissue resident and circulating T cell memory during the immune response is unknown. Here, we find that enhancing NFkB signaling in T cells once memory to influenza is established, increases pro-survival Bcl-2 and CD122 levels thus boosting lung CD8+ TRM maintenance. By contrast, enhancing NFkB signals during the contraction phase of the response leads to a defect in CD8+ TRM differentiation without impairing recirculating memory subsets. Specifically, inducible activation of NFkB via constitutive active IKK2 or TNF interferes with TGFβ signaling, resulting in defects of lung CD8+ TRM imprinting molecules CD69, CD103, Runx3 and Eomes. Conversely, inhibiting NFkB signals not only recovers but improves the transcriptional signature and generation of lung CD8+ TRM. Thus, NFkB signaling is a critical regulator of tissue resident memory, whose levels can be tuned at specific times during infection to boost lung CD8+ TRM

Sphingosine Kinase 1 Serves as a Pro-Viral Factor by Regulating Viral RNA Synthesis and Nuclear Export of Viral Ribonucleoprotein Complex upon Influenza Virus Infection

<div><p>Influenza continues to pose a threat to humans by causing significant morbidity and mortality. Thus, it is imperative to investigate mechanisms by which influenza virus manipulates the function of host factors and cellular signal pathways. In this study, we demonstrate that influenza virus increases the expression and activation of sphingosine kinase (SK) 1, which in turn regulates diverse cellular signaling pathways. Inhibition of SK suppressed virus-induced NF-κB activation and markedly reduced the synthesis of viral RNAs and proteins. Further, SK blockade interfered with activation of Ran-binding protein 3 (RanBP3), a cofactor of chromosome region maintenance 1 (CRM1), to inhibit CRM1-mediated nuclear export of the influenza viral ribonucleoprotein complex. In support of this observation, SK inhibition altered the phosphorylation of ERK, p90RSK, and AKT, which is the upstream signal of RanBP3/CRM1 activation. Collectively, these results indicate that SK is a key pro-viral factor regulating multiple cellular signal pathways triggered by influenza virus infection. </p> </div

SK inhibition suppresses influenza virus replication by impairing activation of the NF-κB signaling pathway.

<p>(A) MDCK cells were left untreated or treated with BAY11-7082 (2.5 µM) and infected with influenza virus at an MOI of 1. The expression of viral proteins M1, NS1, NS2, and actin was assessed by Western blotting at 7 hpi. (B) MDCK cells were treated with solvent or SKI-II (10 µM) and uninfected (Mock) or infected with influenza virus at an MOI of 3. At 0.5, 1, 2, or 4 hpi, Western blot analysis was performed to detect pIKKαβ, IKKαβ, and α-tubulin. (C) MDCK cells were treated with solvent alone or SKI-II (10 µM) and uninfected (Mock) or infected with influenza virus (3 MOI). At 3, 4, 5, or 6 hpi, Western blotting was performed to detect p-p65, p65, and viral M1. (D) MDCK cells were mock-infected or infected with influenza virus at an MOI of 3. They were fixed, permeabilized, and stained with antibodies against NF-κB subunit p65 (red) at 4 hpi and DRAQ5 dye to detect nuclei (blue). Representative confocal images are shown. Scale bar = 50 µm. (E) MDCK cells were co-transfected with NF-κB luciferase reporter plasmid and control Renilla luciferase plasmid. After 12 hrs, cells were treated with solvent alone or SKI-II (10 µM) upon influenza A/Hong Kong/8/68 virus infection at 5 MOI for 7 hrs or were transfected with influenza viral RNA (100 ng) for 7 hrs. Cell lysates were analyzed for luciferase activity with a luminometer. Relative luciferase activities are shown. Values are means ± SEM (n=3). *p<0.05.</p

SK inhibition impairs virus-induced activation of ERK/p90RSK/AKT to inhibit RanBP3-mediated nuclear export of viral NP.

<p>(A and B) HEK293 cells were transfected with scramble siRNA (siCTR) or siRNA targeting RanBP3 (siRanBP3); then the cells were infected with influenza virus at an MOI of 0.01 (A) or 1 (B). RanBP3, pRanBP3, viral M1, and α-tubulin were detected by Western blotting at 30 hpi (A). Viral NP (green) and nuclei (DRAQ5 dye, red) were visualized by confocal microscopy at 12 hpi (B). (C and D) MDCK cells were treated with solvent, DMS (5 µM), or SKI-II (10 µM) and infected with influenza virus at an MOI of 5 for the indicated times (C) or 6 hrs (D). Cell lysates were used for Western blot analysis to detect pRanBP3, RanBP3, α-tubulin, or actin. (E) MDCK cells were left untreated or treated with U0126 (10 µM) or LY294002 (10 µM) and infected with influenza virus at 3 MOI for 6 hrs. Western blot analysis was performed to detect pRanBP3, RanBP3, and GAPDH. (F) MDCK cells were treated with solvent alone or SKI-II (10 µM) and infected with influenza virus at an MOI of 1. Western blot analysis was performed to detect pERK, ERK, p-p90RSK, p90RSK, pRANBP3, or α-tubulin at 12 hpi. (G) MDCK cells were treated with solvent or SKI-II (10 µM) and mock-infected or infected with influenza virus at an MOI of 3. At 8 hpi, pAKT, AKT, and α-tubulin were detected by Western blot analysis.</p