Evidence implicating p38γ and p38δ (p38γ/p38δ) in inflammation are mainly based on experiments using -deficient (p38γ/δKO) mice, which show low levels of TPL2, the kinase upstream of MKK1-ERK1/2 in myeloid cells. This could obscure p38γ/p38δ roles, since TPL2 is essential for regulating inflammation. Here, we generated a / (p38γ/δKIKO) mouse, expressing kinase-inactive p38γ and lacking p38δ. This mouse exhibited normal TPL2 levels, making it an excellent tool to elucidate specific p38γ/p38δ functions. p38γ/δKIKO mice showed a reduced inflammatory response and less susceptibility to lipopolysaccharide (LPS)-induced septic shock and infection than wild-type (WT) mice. Gene expression analyses in LPS-activated wild-type and p38γ/δKIKO macrophages revealed that p38γ/p38δ-regulated numerous genes implicated in innate immune response. Additionally, phospho-proteomic analyses and in vitro kinase assays showed that the transcription factor myocyte enhancer factor-2D (MEF2D) was phosphorylated at Ser444 via p38γ/p38δ. Mutation of MEF2D Ser444 to the non-phosphorylatable residue Ala increased its transcriptional activity and the expression of and mRNA. These results suggest that p38γ/p38δ govern innate immune responses by regulating MEF2D phosphorylation and transcriptional activity.
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http://dx.doi.org/10.7554/eLife.86200 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305.
Exercising regularly promotes health, but these benefits are complicated by acute inflammation induced by exercise. A potential source of inflammation is cell-free DNA (cfDNA), yet the cellular origins, molecular causes, and immune system interactions of exercise-induced cfDNA are unclear. To study these, 10 healthy individuals were randomized to a 12-wk exercise program of either high-intensity tactical training (HITT) or traditional moderate-intensity training (TRAD).
View Article and Find Full Text PDFPLoS One
January 2025
Center for Inflammation, Immunity, & Infection, Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia, United States of America.
Microbiota-induced production of IL-22 by type 3 innate lymphoid cells (ILC3) plays an important role in maintaining intestinal health. Such IL-22 production is driven, in part, by IL-23 produced by gut myeloid cells that have sensed select microbial-derived mediators. The extent to which ILC3 can directly respond to microbial metabolites via IL-22 production is less clear, in part due to the difficulty of isolating and maintaining sufficient numbers of viable ILC3 ex vivo.
View Article and Find Full Text PDFCurr Cardiol Rep
January 2025
Center for Cardiovascular Research, Division of Cardiology, Department of Medicine, Washington University School of Medicine, 660 S Euclid Ave, Campus Box 8086, St. Louis, MO, 63110, USA.
Purpose Of Review: This review aims to explore the role of immune memory and trained immunity, focusing on how innate immune cells like monocytes, macrophages, and natural killer cells undergo long-term epigenetic and metabolic rewiring. Specifically, it examines the mechanisms by which trained immunity, often triggered by infection or vaccination, could impact cardiac processes and contribute to both protective and pathological responses within the cardiovascular system.
Recent Findings: Recent research demonstrates that vaccination and infection not only activate immune responses in circulating monocytes and tissue macrophages but also affect immune progenitor cells within the bone marrow environment, conferring lasting protection against heterologous infections.
J Gen Virol
January 2025
Division of Infection and Immunity, UCL, London, WC1E 6BT, UK.
Human immunodeficiency virus (HIV) is an exemplar virus, still the most studied and best understood and a model for mechanisms of viral replication, immune evasion and pathogenesis. In this review, we consider the earliest stages of HIV infection from transport of the virion contents through the cytoplasm to integration of the viral genome into host chromatin. We present a holistic model for the virus-host interaction during this pivotal stage of infection.
View Article and Find Full Text PDFMicrobiol Spectr
January 2025
Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA.
Unlabelled: Group A (GAS) is a major human pathogen that causes several invasive diseases including necrotizing fasciitis. The host coagulation cascade initiates fibrin clots to sequester bacteria to prevent dissemination into deeper tissues. GAS, especially skin-tropic bacterial strains, utilize specific virulence factors, plasminogen binding M-protein (PAM) and streptokinase (SK), to manipulate hemostasis and activate plasminogen to cause fibrinolysis and fibrin clot escape.
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