Naive and memory human B cells have distinct requirements for STAT3 activation to differentiate into antibody-secreting plasma cells

Long-lived antibody memory is mediated by the combined effects of long-lived plasma cells (PCs) and memory B cells generated in response to T cell–dependent antigens (Ags). IL-10 and IL-21 can activate multiple signaling pathways, including STAT1, STAT3, and STAT5; ERK; PI3K/Akt, and potently promote human B cell differentiation. We previously showed that loss-of-function mutations in STAT3, but not STAT1, abrogate IL-10– and IL-21–mediated differentiation of human naive B cells into plasmablasts. We report here that, in contrast to naive B cells, STAT3-deficient memory B cells responded to these STAT3-activating cytokines, differentiating into plasmablasts and secreting high levels of IgM, IgG, and IgA, as well as Ag-specific IgG. This was associated with the induction of the molecular machinery necessary for PC formation. Mutations in IL21R, however, abolished IL-21–induced responses of both naive and memory human B cells and compromised memory B cell formation in vivo. These findings reveal a key role for IL-21R/STAT3 signaling in regulating human B cell function. Furthermore, our results indicate that the threshold of STAT3 activation required for differentiation is lower in memory compared with naive B cells, thereby identifying an intrinsic difference in the mechanism underlying differentiation of naive versus memory B cells.This work was funded by project and program grants from the National Health and Medical Research Council (NHMRC) of Australia (to E.K. Deenick, C.S. Ma, D.A. Fulcher, M.C. Cook, and S.G. Tangye) and the Rockefeller University Center for 541 Clinical and Translational science (5UL1RR024143 to J.L. Casanova). C.S. Ma is a recipient of a Career Development Fellowship, L.J. Berglund is a recipient of a Medical Postgraduate Scholarship, and S.G. Tangye is a recipient of a Principal Research Fellowship from the NHMRC of Australia. L. Moens is the recipient of a Postdoctoral Fellowship from the Research Foundation-Flanders (FWO), Belgium

ADRA1A-Gα_q signalling potentiates adipocyte thermogenesis through CKB and TNAP

Noradrenaline (NA) regulates cold-stimulated adipocyte thermogenesis(1). Aside from cAMP signalling downstream of β-adrenergic receptor activation, how NA promotes thermogenic output is still not fully understood. Here, we show that coordinated α(1)-adrenergic receptor (AR) and β(3)-AR signalling induces the expression of thermogenic genes of the futile creatine cycle(2,3), and that early B cell factors, oestrogen-related receptors and PGC1α are required for this response in vivo. NA triggers physical and functional coupling between the α(1)-AR subtype (ADRA1A) and Gα(q) to promote adipocyte thermogenesis in a manner that is dependent on the effector proteins of the futile creatine cycle, creatine kinase B and tissue-non-specific alkaline phosphatase. Combined Gα(q) and Gα(s) signalling selectively in adipocytes promotes a continual rise in whole-body energy expenditure, and creatine kinase B is required for this effect. Thus, the ADRA1A–Gα(q)–futile creatine cycle axis is a key regulator of facultative and adaptive thermogenesis

COA6 is structurally tuned to function as a thiol-disulfide oxidoreductase in copper delivery to mitochondrial cytochrome c oxidase

In eukaryotes, cellular respiration is driven by mitochondrial cytochrome c oxidase (CcO), an enzyme complex that requires copper cofactors for its catalytic activity. Insertion of copper into its catalytically active subunits, including COX2, is a complex process that requires metallochaperones and redox proteins including SCO1, SCO2, and COA6, a recently discovered protein whose molecular function is unknown. To uncover the molecular mechanism by which COA6 and SCO proteins mediate copper delivery to COX2, we have solved the solution structure of COA6, which reveals a coiled-coil-helix-coiled-coilhelix domain typical of redox-active proteins found in the mitochondrial inter-membrane space. Accordingly, we demonstrate that COA6 can reduce the copper-coordinating disulfides of its client proteins, SCO1 and COX2, allowing for copper binding. Finally, our determination of the interaction surfaces and reduction potentials of COA6 and its client proteins provides a mechanism of how metallochaperone and disulfide reductase activities are coordinated to deliver copper to CcO.Fil: Soma, Shivatheja. Texas A&M University. Department of Biochemistry and Biophysics; United States.Fil: Morgada, Marcos N. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario (IBR -CONICET); Argentina.Fil: Morgada, Marcos N. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Biológica. Área Biofísica; Argentina.Fil: Naik, Mandar T. Texas A&M University. Department of Biochemistry and Biophysics; United States.Fil: Naik, Mandar T. Brown University. Department of Molecular Pharmacology, Physiology, and Biotechnology; United States.Fil: Boulet, Aren. University of Saskatchewan. Department of Biochemistry, Microbiology and Immunology; Canada.Fil: Roesler, Anna A. University of Saskatchewan. Department of Biochemistry, Microbiology and Immunology; Canada.Fil: Dziuba, Nathaniel. Texas A&M University. Department of Biochemistry and Biophysics; United States.Fil: Ghosh, Alok. Texas A&M University. Department of Biochemistry and Biophysics; United States.Fil: Ghosh, Alok. University of Calcutta. Department of Biochemistry; India.Fil: Yu, Qinhong. University of California. Department of Chemistry; United States.Fil: Lindahl, Paul A. Texas A&M University. Department of Biochemistry and Biophysics; United States.Fil: Lindahl, Paul A. Texas A&M University. Department of Chemistry; United States.Fil: Ames, James B. University of California. Department of Chemistry; United States.Fil: Leary, Scot C. University of Saskatchewan. Department of Biochemistry, Microbiology and Immunology; Canada.Fil: Vila, Alejandro J. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario (IBR -CONICET); Argentina.Fil: Vila, Alejandro J. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Biológica. Área Biofísica; Argentina.Fil: Gohil, Vishal M. Texas A&M University. Department of Biochemistry and Biophysics; United States

Applications of FLUKA Monte Carlo code for nuclear and accelerator physics

FLUKA is a general purpose Monte Carlo code capable of handling all radiation components from thermal energies (for neutrons) or 1 keV (for all other particles) to cosmic ray energies and can be applied in many different fields. Presently the code is maintained on Linux. The validity of the physical models implemented in FLUKA has been benchmarked against a variety of experimental data over a wide energy range, from accelerator data to cosmic ray showers in the Earth atmosphere. FLUKA is widely used for studies related both to basic research and to applications in particle accelerators, radiation protection and dosimetry, including the specific issue of radiation damage in space missions, radiobiology (including radiotherapy) and cosmic ray calculations. After a short description of the main features that make FLUKA valuable for these topics, the present paper summarizes some of the recent applications of the FLUKA Monte Carlo code in the nuclear as well high energy physics. In particular it addresses such topics as accelerator related applications

ADRA1A-Gα signalling potentiates adipocyte thermogenesis through CKB and TNAP

Noradrenaline (NA) regulates cold-stimulated adipocyte thermogenesis. Aside from cAMP signalling downstream of β-adrenergic receptor activation, how NA promotes thermogenic output is still not fully understood. Here, we show that coordinated α-adrenergic receptor (AR) and β-AR signalling induces the expression of thermogenic genes of the futile creatine cycle, and that early B cell factors, oestrogen-related receptors and PGC1α are required for this response in vivo. NA triggers physical and functional coupling between the α-AR subtype (ADRA1A) and Gα to promote adipocyte thermogenesis in a manner that is dependent on the effector proteins of the futile creatine cycle, creatine kinase B and tissue-non-specific alkaline phosphatase. Combined Gα and Gα signalling selectively in adipocytes promotes a continual rise in whole-body energy expenditure, and creatine kinase B is required for this effect. Thus, the ADRA1A-Gα-futile creatine cycle axis is a key regulator of facultative and adaptive thermogenesis

Signal transducer and activator of transcription 3 (STAT3) mutations underlying autosomal dominant hyper-IgE syndrome impair human CD81 T-cell memory formation and function

Background The capacity of CD8+ T cells to control infections and mediate antitumor immunity requires the development and survival of effector and memory cells. IL-21 has emerged as a potent inducer of CD8+ T-cell effector function and memory development in mouse models of infectious disease. However, the role of IL-21 and associated signaling pathways in protective CD8+ T-cell immunity in human subjects is unknown. Objective We sought to determine which signaling pathways mediate the effects of IL-21 on human CD8+ T cells and whether defects in these pathways contribute to disease pathogenesis in patients with primary immunodeficiencies caused by mutations in components of the IL-21 signaling cascade. Methods Human primary immunodeficiencies resulting from monogenic mutations provide a unique opportunity to assess the requirement for particular molecules in regulating human lymphocyte function. Lymphocytes from patients with loss-of-function mutations in signal transducer and activator of transcription 1 (STAT1), STAT3, or IL-21 receptor (IL21R) were used to assess the respective roles of these genes in human CD8+ T-cell differentiation in vivo and in vitro. Results Mutations in STAT3 and IL21R, but not STAT1, led to a decrease in multiple memory CD8+ T-cell subsets in vivo, indicating that STAT3 signaling, possibly downstream of IL-21R, regulates the memory cell pool. Furthermore, STAT3 was important for inducing the lytic machinery in IL-21–stimulated naive CD8+ T cells. However, this defect was overcome by T-cell receptor engagement. Conclusion The IL-21R/STAT3 pathway is required for many aspects of human CD8+ T-cell behavior but in some cases can be compensated by other signals. This helps explain the relatively mild susceptibility to viral disease observed in STAT3- and IL-21R–deficient subjects.Supported by project and program grants from the National Health and Medical Research Council (NHMRC) of Australia (to E.K.D., S.G.T., C.S.M., D.A.F., and M.C.C.), Cancer Council NSW (to S.G.T. and U.P.), and Rockefeller University Center for 541 Clinical and Translational science (5UL1RR024143, to J.-L.C.). C.S.M. is a recipient of a Career Development Fellowship and S.G.T. is a recipient of a Principal Research Fellowship from the NHMRC of Australia. Disclosure of potential conflict of interest: C. S. Ma has been supported by one or more grants from the National Health and Medical Research Council of Australia (NHMRC). J. Peake has received one or more payments for lecturing on allergy topics and has been reimbursed for travel/accommodations/meeting expenses. M. A. French has received one or more payments for lecturing from or is on the speakers’ bureau for ViiV Australia, MSD Australia, and Janssen Australia and has received one or more payments for travel/accommodations/meeting expenses from MSD Australia and ViiVAustralia. J.-L. Casanova has been supported by one or more grants from the National Institutes of Health (grant no. 8UL1TR000043); has consultancy arrangements with Regeneron, GlaxoSmithKline, NovImmune, BiogenIdec, Merck, and Sanofi- Aventis; and has received one or more grants from or has one or more grants pending with Merck. S. G. Tangye has been supported by one or more grants from the NHMRC of Australia; has received support for travel from ESID, Keystone Symposia, and the Jeffrey Modell Foundation; and has received one or more fees for serving as an expert witness in a patent dispute. E. K. Deenick has been supported by one or more grants from NHMRC, has received one or more payments for travel/accommodations/meeting expenses from the Japanese Society for Immunology, and has received one or more paid honoraria as an Editor for Immunology and Cell Biology. The rest of the authors declare that they have no relevant conflicts of interest