scholarly journals A genome-wide screen in macrophages identifies new regulators of IFNγ-inducible MHCII that contribute to T cell activation

2020 ◽  
Author(s):  
Michael C. Kiritsy ◽  
Laurisa M. Ankley ◽  
Justin D. Trombley ◽  
Gabrielle P. Huizinga ◽  
Audrey E. Lord ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Glycogen Synthase ◽  
Surface Expression ◽  
Host Immunity ◽  
Dynamic Regulation ◽  
Genome Wide ◽  
A Genome ◽  
Mhcii Expression

AbstractCytokine-mediated activation of host immunity is central to the control of pathogens. A key cytokine in protective immunity is interferon-gamma (IFNγ), which is a potent activator of antimicrobial and immunomodulatory effectors within the host. A major role of IFNγ is to induce major histocompatibility complex class II molecules (MHCII) on the surface of cells, which is required for CD4+ T cell activation. Despite its central role in host immunity, the complex and dynamic regulation of IFNγ-induced MHCII is not well understood. Here, we integrated functional genomics and transcriptomics to comprehensively define the genetic control of IFNγ-mediated MHCII surface expression in macrophages. Using a genome-wide CRISPR-Cas9 library we identified genes that control MHCII surface expression, many of which have yet to be associated with MHCII. Mechanistic studies uncovered two parallel pathways of IFNγ-mediated MHCII control that require the multifunctional glycogen synthase kinase 3 beta (GSK3β) or the mediator complex subunit MED16. Both pathways are necessary for IFNγ-mediated induction of the MHCII transactivator CIITA, MHCII expression, and CD4+ T cell activation. Using transcriptomic analysis, we defined the regulons controlled by GSK3β and MED16 in the presence and absence of IFNγ and identified unique networks of the IFNγ-mediated transcriptional landscape that are controlled by each gene. Our analysis suggests GSK3β and MED16 control distinct aspects of the IFNγ-response and are critical for macrophages to respond appropriately to IFNγ. Our results define previously unappreciated regulation of MHCII expression that is required to control CD4+ T cell responses by macrophages. These discoveries will aid in our basic understanding of macrophage-mediated immunity and will shed light on mechanisms of failed adaptive responses pervasive in infectious disease, autoimmunity, and cancer.

scholarly journals A genetic screen in macrophages identifies new regulators of IFNγ-inducible MHCII that contribute to T cell activation

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Michael C Kiritsy ◽  
Laurisa M Ankley ◽  
Justin Trombley ◽  
Gabrielle P Huizinga ◽  
Audrey E Lord ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Glycogen Synthase ◽  
Surface Expression ◽  
Dynamic Regulation ◽  
Cell Responses ◽  
Genome Wide ◽  
A Genome ◽  
Mhcii Expression

Cytokine-mediated activation of host immunity is central to the control of pathogens. Interferon-gamma (IFNg) is a key cytokine in protective immunity that induces major histocompatibility complex class II molecules (MHCII) to amplify CD4+ T cell activation and effector function. Despite its central role, the dynamic regulation of IFNg-induced MHCII is not well understood. Using a genome-wide CRISPR-Cas9 screen in murine macrophages we identified genes that control MHCII surface expression. Mechanistic studies uncovered two parallel pathways of IFNg-mediated MHCII control that require the multifunctional glycogen synthase kinase 3 beta (GSK3b) or the mediator complex subunit MED16. Both pathways control distinct aspects of the IFNg response and are necessary for IFNg-mediated induction of the MHCII transactivator Ciita, MHCII expression, and CD4+ T cell activation. Our results define previously unappreciated regulation of MHCII expression that is required to control CD4+ T cell responses.

scholarly journals Genome-wide CRISPR screen identifies FAM49B as a key regulator of actin dynamics and T cell activation

2018 ◽  
Vol 115 (17) ◽  
pp. E4051-E4060 ◽  
Author(s):  
Wanjing Shang ◽  
Yong Jiang ◽  
Michael Boettcher ◽  
Kang Ding ◽  
Marianne Mollenauer ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
T Cell Activation ◽  
Cell Activation ◽  
Active Form ◽  
Cell Receptor ◽  
Small Gtpase ◽  
Genome Wide ◽  
A Genome ◽  
Crispr Screen

Despite decades of research, mechanisms controlling T cell activation remain only partially understood, which hampers T cell-based immune cancer therapies. Here, we performed a genome-wide CRISPR screen to search for genes that regulate T cell activation. Our screen confirmed many of the known regulators in proximal T cell receptor signaling and, importantly, also uncovered a previously uncharacterized regulator, FAM49B (family with sequence similarity 49 member B). FAM49B deficiency led to hyperactivation of Jurkat T cells following T cell receptor stimulation, as indicated by enhancement of CD69 induction, PAK phosphorylation, and actin assembly. FAM49B directly interacted with the active form of the small GTPase Rac, and genetic disruption of the FAM49B–Rac interaction compromised FAM49B function. Thus, FAM49B inhibits T cell activation by repressing Rac activity and modulating cytoskeleton reorganization.

scholarly journals Dynamic regulation of T cell activation and co-stimulation through TCR-microclusters

FEBS Letters ◽  
2010 ◽  
Vol 584 (24) ◽  
pp. 4865-4871 ◽  
Author(s):  
Takashi Saito ◽  
Tadashi Yokosuka ◽  
Akiko Hashimoto-Tane
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Dynamic Regulation

scholarly journals Glycogen Synthase Kinase-3 Modulates Cbl-b and Constrains T Cell Activation

2017 ◽  
Vol 199 (12) ◽  
pp. 4056-4065 ◽  
Author(s):  
Charles W. Tran ◽  
Samuel D. Saibil ◽  
Thierry Le Bihan ◽  
Sara R. Hamilton ◽  
Karl S. Lang ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3

scholarly journals Herpes Simplex Virus γ34.5 Interferes with Autophagosome Maturation and Antigen Presentation in Dendritic Cells

mBio ◽  
2012 ◽  
Vol 3 (5) ◽  
Author(s):  
Philipe A. M. Gobeil ◽  
David A. Leib
Keyword(s):  
Dendritic Cells ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Host Immunity ◽  
Herpes Simplex Virus 1 ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACTThe cellular autophagy response induced by herpes simplex virus 1 (HSV-1) is countered by the viral γ34.5 protein. γ34.5 modulates autophagy by binding to the host autophagy protein Beclin-1 and through this binding inhibits the formation of autophagosomes in fibroblasts and neurons. In contrast, in this study dendritic cells (DCs) infected with HSV-1 showed an accumulation of autophagosomes and of the long-lived protein p62. No such accumulations were observed in DCs infected with a γ34.5-null virus or a virus lacking the Beclin-binding domain (BBD) of γ34.5. To explore this further, we established stably transduced DC lines to show that γ34.5 expression alone induced autophagosome accumulation yet prevented p62 degradation. In contrast, DCs expressing a BBD-deleted mutant of γ34.5 were unable to modulate autophagy. DCs expressing γ34.5 were less capable of stimulating T-cell activation and proliferation in response to intracellular antigens, demonstrating an immunological consequence of inhibiting autophagy. Taken together, these data show that in DCs, γ34.5 antagonizes the maturation of autophagosomes and T cell activation in a BBD-dependent manner, illustrating a unique interface between HSV and autophagy in antigen-presenting cells.IMPORTANCEHerpes simplex virus 1 (HSV-1) is a highly prevalent pathogen causing widespread morbidity and some mortality. HSV infections are lifelong, and there are no vaccines or antivirals to cure HSV infections. The ability of HSV to modulate host immunity is critical for its virulence. HSV inhibits host autophagy, a pathway with importance in many areas of health and disease. Autophagy is triggered by many microbes, some of which harness autophagy for replication; others evade autophagy or prevent it from occurring. Autophagy is critical for host defense, either by directly degrading the invading pathogen (“xenophagy”) or by facilitating antigen presentation to T cells. In this study, we show that HSV manipulates autophagy through an unsuspected mechanism with a functional consequence of reducing T cell stimulation. These data further our understanding of how HSV evades host immunity to persist for the lifetime of its host, facilitating its spread in the human population.

scholarly journals Genome-wide transcriptional analysis of T cell activation reveals differential gene expression associated with psoriasis

BMC Genomics ◽  
2013 ◽  
Vol 14 (1) ◽  
pp. 825 ◽  
Author(s):  
Nuria Palau ◽  
Antonio Julià ◽  
Carlos Ferrándiz ◽  
Lluís Puig ◽  
Eduardo Fonseca ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cell ◽  
Differential Gene Expression ◽  
T Cell Activation ◽  
Cell Activation ◽  
Transcriptional Analysis ◽  
Genome Wide ◽  
Differential Gene

scholarly journals Epigenetic Alterations in Cellular Immunity: New Insights into Autoimmune Diseases

2017 ◽  
Vol 41 (2) ◽  
pp. 645-660 ◽  
Author(s):  
Zijun Wang ◽  
Qianjin Lu ◽  
Zhihui Wang
Keyword(s):  
T Cell ◽  
Autoimmune Diseases ◽  
T Cell Activation ◽  
Cellular Immunity ◽  
Cell Activation ◽  
Epigenetic Modification ◽  
Epigenetic Modifications ◽  
Cell Immunity ◽  
Genome Wide ◽  
Epigenetic Events

Epigenetic modification is an additional regulator in immune responses as the genome-wide profiling somehow fails to explain the sophisticated mechanisms in autoimmune diseases. The effect of epigenetic modifications on adaptive immunity derives from their regulations to induce a permissive or negative gene expression. Epigenetic events, such as DNA methylation, histone modifications and microRNAs (miRNAs) are often found in T cell activation, differentiation and commitment which are the major parts in cellular immunity. Recognizing the complexity of interactions between epigenetic mechanisms and immune disturbance in autoimmune diseases is essential for the exploration of efficient therapeutic targets. In this review, we summarize a list of studies that indicate the significance of dysregulated epigenetic modifications in autoimmune diseases while focusing on T cell immunity.

scholarly journals Lipoprotein-Dependent and -Independent Immune Responses to Spirochetal Infection

2005 ◽  
Vol 12 (8) ◽  
pp. 949-958 ◽  
Author(s):  
Juan C. Salazar ◽  
Constance D. Pope ◽  
Meagan W. Moore ◽  
Jonathan Pope ◽  
Thomas G. Kiely ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Erythema Migrans ◽  
Surface Expression ◽  
Intradermal Injection ◽  
Human Infection ◽  
T Cell Subsets ◽  
Interleukin 12 ◽  
Multiparameter Flow Cytometry

ABSTRACT In this study, we used the epidermal suction blister technique, in conjunction with multiparameter flow cytometry, to analyze the cellular and cytokine responses elicited by intradermal injection of human volunteers with synthetic analogs for spirochetal lipoproteins and compared the responses to findings previously reported from patients with erythema migrans (EM). Compared with peripheral blood (PB), lipopeptides derived from the N termini of the Borrelia burgdorferi outer surface protein C and the 17-kDa lipoprotein of Treponema pallidum (OspC-L and 17-L, respectively) elicited infiltrates enriched in monocytes/macrophages and dendritic cells (DCs) but also containing substantial percentages of neutrophils and T cells. Monocytoid (CD11c+) and plasmacytoid (CD11c−) DCs were selectively recruited to the skin in ratios similar to those in PB, but only the former expressed the activation/maturation surface markers CD80, CD83, and DC-SIGN. Monocytes/macrophages and monocytoid DCs, but not plasmacytoid DCs, displayed significant increases in surface expression of Toll-like receptor 1 (TLR1), TLR2, and TLR4. Staining for CD45RO and CD27 revealed that lipopeptides preferentially recruited antigen-experienced T-cell subsets; despite their lack of antigenicity, these agonists induced marked T-cell activation, as evidenced by surface expression of CD69, CD25, and CD71. Lipopeptides also induced significant increases in interleukin 12 (IL-12), IL-10, gamma interferon, and most notably IL-6 without corresponding increases in serum levels of these cytokines. Although lipopeptides and EM lesional infiltrates shared many similarities, differences were noted in a number of immunologic parameters. These studies have provided in situ evidence for a prominent “lipoprotein effect” during human infection while at the same time helping to pinpoint aspects of the cutaneous response that are uniquely driven by spirochetal pathogens.

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