Necroptosis of Dendritic Cells Promotes Activation of γδ T Cells

Necroptosis and autoimmunity

Autoimmunity is a normal physiological state that requires immunological homeostasis and surveillance, whereas necroptosis is a type of inflammatory cell death. When necroptosis occurs, various immune system cells must perform their appropriate duties to preserve immunological homeostasis, whether the consequence is expanding or limiting the inflammatory response and the pathological condition is cleared or progresses to the autoimmune disease stage. This article discusses necroptosis based on RIP homotypic interaction motif (RHIM) interaction under various physiological and pathological situations, with the RIPK1-RIPK3-MLKL necrosome serving as the regulatory core. In addition, the cell biology of necroptosis involved in autoimmunity and its application in autoimmune diseases were also reviewed.

The crosstalk between ferroptosis and anti-tumor immunity in the tumor microenvironment: molecular mechanisms and therapeutic controversy

The advent of immunotherapy has significantly reshaped the landscape of cancer treatment, greatly enhancing therapeutic outcomes for multiple types of cancer. However, only a small subset of individuals respond to it, underscoring the urgent need for new methods to improve its response rate. Ferroptosis, a recently discovered form of programmed cell death, has emerged as a promising approach for anti-tumor therapy, with targeting ferroptosis to kill tumors seen as a potentially effective strategy. Numerous studies suggest that inducing ferroptosis can synergistically enhance the effects of immunotherapy, paving the way for a promising combined treatment method in the future. Nevertheless, recent research has raised concerns about the potential negative impacts on anti-tumor immunity as a consequence of inducing ferroptosis, leading to conflicting views within the scientific community about the interplay between ferroptosis and anti-tumor immunity, thereby underscoring the necessity of a comprehensive review of the existing literature on this relationship. Previous reviews on ferroptosis have touched on related content, many focusing primarily on the promoting role of ferroptosis on anti-tumor immunity while overlooking recent evidence on the inhibitory effects of ferroptosis on immunity. Others have concentrated solely on discussing related content either from the perspective of cancer cells and ferroptosis or from immune cells and ferroptosis. Given that both cancer cells and immune cells exist in the tumor microenvironment, a one-sided discussion cannot comprehensively summarize this topic. Therefore, from the perspectives of both tumor cells and tumor-infiltrating immune cells, we systematically summarize the current conflicting views on the interplay between ferroptosis and anti-tumor immunity, intending to provide potential explanations and identify the work needed to establish a translational basis for combined ferroptosis-targeted therapy and immunotherapy in treating tumors.

Effect of Streptococcus uberis on Gamma Delta T Cell Phenotype in Bovine Mammary Gland

Simple Summary

Bovine mastitis (inflammation of the mammary gland) is still an important problem for dairy farmers. This disease causes great financial losses across the world. The common method of treating mastitis is through the use of antibiotics. Antibiotic treatment should be minimized because of increasing antibiotic resistance. Streptococcus uberis (S. uberis) is one of the most important pathogens that causes bovine mastitis. This bacterium is able to hide and survive inside of epithelial cells. In this situation, antibiotic treatment is not efficient. Therefore, it is necessary to study the pathogenesis of mastitis that is caused by S. uberis to better understand how to treat this disease. In this study, we investigated a special type of lymphocytes—γδ T cells. The results of our study show that those cells may play a role in terminating inflammation in the mammary glands of cattle.

Abstract

In this study, we focused analyzing γδ T cells during bovine mammary gland inflammation induced by Streptococcus uberis. A mammary gland cell suspension was obtained using lavage 24, 48, 72, and 168 h after intramammary-induced infection. The proportion of lymphocytes increased during the entire week in which inflammation was present. The γδ T cells were also elevated during inflammation, reaching their peak at 72 h following induced inflammation. The percentage of apoptotic lymphocytes continually increased, with the highest proportion occurring 168 h after S. uberis infection. The results show that γδ T cells may be involved in the resolution of inflammation in bovine mammary glands, with the apoptosis of those cells potentially playing an important role.

Immune Response to Borrelia: Lessons from Lyme Disease Spirochetes

The mammalian host responds to infection with Borrelia spirochetes through a highly orchestrated immune defense involving innate and adaptive effector functions aimed toward limiting pathogen burdens, minimizing tissue injury, and preventing subsequent reinfection. The evolutionary adaptation of Borrelia spirochetes to their reservoir mammalian hosts may allow for its persistence despite this immune defense. This review summarizes our current understanding of the host immune response to B. burgdorferi sensu lato, the most widely studied Borrelia spp. and etiologic agent of Lyme borreliosis. Pertinent literature will be reviewed with emphasis on in vitro, ex vivo and animal studies that influenced our understanding of both the earliest responses to B. burgdorferi as it enters the mammalian host and those that evolve as spirochetes disseminate and establish infection in multiple tissues. Our focus is on the immune response of inbred mice, the most commonly studied animal model of B. burgdorferi infection and surrogate for one of this pathogen's principle natural reservoir hosts, the white-footed deer mouse. Comparison will be made to the immune responses of humans with Lyme borreliosis. Our goal is to provide an understanding of the dynamics of the mammalian immune response during infection with B. burgdorferi and its relation to the outcomes in reservoir (mouse) and non-reservoir (human) hosts.

Necroptotic cell binding of β2 -glycoprotein I provides a potential autoantigenic stimulus in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is characterized by the development of autoantibodies against diverse self-antigens with damage to multiple organs. Immunization with the SLE autoantigen β₂ -glycoprotein I (β₂ GPI) and lipopolysaccharide (LPS), a known trigger of necroptosis, induces a murine model of SLE. We hypothesized that necroptotic cells, like apoptotic cells, provide a "scaffold" of cellular self-antigens, but, unlike apoptotic cells, necroptotic cells do so in a proinflammatory and immunogenic context. We demonstrate that β₂ GPI indeed binds to necroptotic cells and serves as a target for anti-β₂ GPI autoantibodies. We further demonstrate that necroptotic, but not apoptotic, cells promote antigenic presentation of β₂ GPI to CD4 T cells by dendritic cells. Finally, we show that β₂ GPI/LPS-immunized mice deficient in RIPK3 (receptor-interacting serine/threonine-protein kinase 3) or MLKL (mixed lineage kinase domain like), and consequently unable to undergo necroptosis, have reduced SLE autoantibody production and pathology. RIPK3^-/- mice had low levels of SLE autoantibodies and no renal pathology, while MLKL^-/- mice produced low levels of SLE autoantibodies initially, but later developed levels comparable with wild type (WT) mice and pathology intermediate to that of WT and RIPK3^-/- mice. Serum cytokine levels induced by LPS tended to be lower in RIPK3^-/- and MLKL^-/- mice than in WT mice, suggesting that impaired proinflammatory cytokine production may impact the initiation of autoantibody production in both strains. Our data suggest that self-antigen (i.e. β₂ GPI) presented in the context of necroptosis and proinflammatory signals may be sufficient to overcome immune tolerance and induce SLE.