Browsing by Subject "Neutrophil"

Now showing 1 - 7 of 7
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    BCL6 modulates tissue neutrophil survival and exacerbates pulmonary inflammation following influenza virus infection
    (National Academy of Sciences, 2019-06-11) Zhu, Bibo; Zhang, Ruixuan; Li, Chaofan; Jiang, Li; Xiang, Min; Ye, Zhenqing; Kita, Hirohito; Melnick, Ari M.; Dent, Alexander L.; Sun, Jie; Pediatrics, School of Medicine
    Neutrophils are vital for antimicrobial defense; however, their role during viral infection is less clear. Furthermore, the molecular regulation of neutrophil fate and function at the viral infected sites is largely elusive. Here we report that BCL6 deficiency in myeloid cells exhibited drastically enhanced host resistance to severe influenza A virus (IAV) infection. In contrast to the notion that BCL6 functions to suppress innate inflammation, we find that myeloid BCL6 deficiency diminished lung inflammation without affecting viral loads. Using a series of Cre-transgenic, reporter, and knockout mouse lines, we demonstrate that BCL6 deficiency in neutrophils, but not in monocytes or lung macrophages, attenuated host inflammation and morbidity following IAV infection. Mechanistically, BCL6 bound to the neutrophil gene loci involved in cellular apoptosis in cells specifically at the site of infection. As such, BCL6 disruption resulted in increased expression of apoptotic genes in neutrophils in the respiratory tract, but not in the circulation or bone marrow. Consequently, BCL6 deficiency promoted tissue neutrophil apoptosis. Partial neutrophil depletion led to diminished pulmonary inflammation and decreased host morbidity. Our results reveal a previously unappreciated role of BCL6 in modulating neutrophil apoptosis at the site of infection for the regulation of host disease development following viral infection. Furthermore, our studies indicate that tissue-specific regulation of neutrophil survival modulates host inflammation and tissue immunopathology during acute respiratory viral infection.
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    c-Met Mediated Cytokine Network Promotes Brain Metastasis of Breast Cancer by Remodeling Neutrophil Activities
    (MDPI, 2023-05-05) Liu, Yin; Smith, Margaret R.; Wang, Yuezhu; D’Agostino, Ralph, Jr.; Ruiz, Jimmy; Lycan, Thomas; Kucera, Gregory L.; Miller, Lance D.; Li, Wencheng; Chan, Michael D.; Farris, Michael; Su, Jing; Song, Qianqian; Zhao, Dawen; Chandrasekaran, Arvind; Xing, Fei; Biostatistics and Health Data Science, School of Medicine
    The brain is one of the most common metastatic sites among breast cancer patients, especially in those who have Her2-positive or triple-negative tumors. The brain microenvironment has been considered immune privileged, and the exact mechanisms of how immune cells in the brain microenvironment contribute to brain metastasis remain elusive. In this study, we found that neutrophils are recruited and influenced by c-Met high brain metastatic cells in the metastatic sites, and depletion of neutrophils significantly suppressed brain metastasis in animal models. Overexpression of c-Met in tumor cells enhances the secretion of a group of cytokines, including CXCL1/2, G-CSF, and GM-CSF, which play critical roles in neutrophil attraction, granulopoiesis, and homeostasis. Meanwhile, our transcriptomic analysis demonstrated that conditioned media from c-Met high cells significantly induced the secretion of lipocalin 2 (LCN2) from neutrophils, which in turn promotes the self-renewal of cancer stem cells. Our study unveiled the molecular and pathogenic mechanisms of how crosstalk between innate immune cells and tumor cells facilitates tumor progression in the brain, which provides novel therapeutic targets for treating brain metastasis.
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    Early innate and adaptive immune perturbations determine long-term severity of chronic virus and Mycobacterium tuberculosis coinfection
    (Elsevier, 2021) Xu, Wenxi; Snell, Laura M.; Guo, Mengdi; Boukhaled, Giselle; Macleod, Bethany L.; Li, Ming; Tullius, Michael V.; Guidos, Cynthia J.; Tsao, Ming-Sound; Divangahi, Maziar; Horwitz, Marcus A.; Liu, Jun; Brooks, David G.; Microbiology and Immunology, School of Medicine
    Chronic viral infections increase severity of Mycobacterium tuberculosis (Mtb) coinfection. Here, we examined how chronic viral infections alter the pulmonary microenvironment to foster coinfection and worsen disease severity. We developed a coordinated system of chronic virus and Mtb infection that induced central clinical manifestations of coinfection, including increased Mtb burden, extra-pulmonary dissemination, and heightened mortality. These disease states were not due to chronic virus-induced immunosuppression or exhaustion; rather, increased amounts of the cytokine TNFα initially arrested pulmonary Mtb growth, impeding dendritic cell mediated antigen transportation to the lymph node and subverting immune-surveillance, allowing bacterial sanctuary. The cryptic Mtb replication delayed CD4 T cell priming, redirecting T helper (Th) 1 toward Th17 differentiation and increasing pulmonary neutrophilia, which diminished long-term survival. Temporally restoring CD4 T cell induction overcame these diverse disease sequelae to enhance Mtb control. Thus, Mtb co-opts TNFα from the chronic inflammatory environment to subvert immune-surveillance, avert early immune function, and foster long-term coinfection.
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    Neutrophils Resist Ferroptosis and Promote Breast Cancer Metastasis through Aconitate Decarboxylase 1
    (Elsevier, 2023) Zhao, Yun; Liu, Zhongshun; Liu, Guoqiang; Zhang, Yuting; Liu, Sheng; Gan, Dailin; Chang, Wennan; Peng, Xiaoxia; Sung, Eun Suh; Gilbert, Keegan; Zhu, Yini; Wang, Xuechun; Zeng, Ziyu; Baldwin, Hope; Ren, Guanzhu; Weaver, Jessica; Huron, Anna; Mayberry, Toni; Wang, Qingfei; Wang, Yujue; Diaz-Rubio, Maria Elena; Su, Xiaoyang; Stack, M. Sharon; Zhang, Siyuan; Lu, Xuemin; Sheldon, Ryan D.; Li, Jun; Zhang, Chi; Wan, Jun; Lu, Xin; Medical and Molecular Genetics, School of Medicine
    Metastasis causes breast cancer-related mortality. Tumor-infiltrating neutrophils (TINs) inflict immunosuppression and promote metastasis. Therapeutic debilitation of TINs may enhance immunotherapy, yet it remains a challenge to identify therapeutic targets highly expressed and functionally essential in TINs but under-expressed in extra-tumoral neutrophils. Here, using single-cell RNA sequencing to compare TINs and circulating neutrophils in murine mammary tumor models, we identified aconitate decarboxylase 1 (Acod1) as the most upregulated metabolic enzyme in mouse TINs and validated high Acod1 expression in human TINs. Activated through the GM-CSF-JAK/STAT5-C/EBPβ pathway, Acod1 produces itaconate, which mediates Nrf2-dependent defense against ferroptosis and upholds the persistence of TINs. Acod1 ablation abates TIN infiltration, constrains metastasis (but not primary tumors), bolsters antitumor T cell immunity, and boosts the efficacy of immune checkpoint blockade. Our findings reveal how TINs escape from ferroptosis through the Acod1-dependent immunometabolism switch and establish Acod1 as a target to offset immunosuppression and improve immunotherapy against metastasis.
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    Periostin activates distinct modules of inflammation and itching downstream of the type 2 inflammation pathway
    (Elsevier, 2023) Nunomura, Satoshi; Uta, Daisuke; Kitajima, Isao; Nanri, Yasuhiro; Matsuda, Kosuke; Ejiri, Naoko; Kitajima, Midori; Ikemitsu, Hitoshi; Koga, Misaki; Yamamoto, Sayaka; Honda, Yuko; Takedomi, Hironobu; Andoh, Tsugunobu; Conway, Simon J.; Izuhara, Kenji; Pediatrics, School of Medicine
    Atopic dermatitis (AD) is a chronic relapsing skin disease accompanied by recurrent itching. Although type 2 inflammation is dominant in allergic skin inflammation, it is not fully understood how non-type 2 inflammation co-exists with type 2 inflammation or how type 2 inflammation causes itching. We have recently established the FADS mouse, a mouse model of AD. In FADS mice, either genetic disruption or pharmacological inhibition of periostin, a downstream molecule of type 2 inflammation, inhibits NF-κB activation in keratinocytes, leading to downregulating eczema, epidermal hyperplasia, and infiltration of neutrophils, without regulating the enhanced type 2 inflammation. Moreover, inhibition of periostin blocks spontaneous firing of superficial dorsal horn neurons followed by a decrease in scratching behaviors due to itching. Taken together, periostin links NF-κB-mediated inflammation with type 2 inflammation and promotes itching in allergic skin inflammation, suggesting that periostin is a promising therapeutic target for AD.
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    Polytrauma: update on basic science and clinical evidence
    (Wolters Kluwer, 2021-02-23) Nauth, Aaron; Hildebrand, Frank; Vallier, Heather; Moore, Timothy; Leenen, Luke; Mckinley, Todd; Pape, Hans-Christoph; Orthopaedic Surgery, School of Medicine
    The management of multiply injured or severely injured patients is a complex and dynamic process. Timely and safe fracture fixation is a critical component of the multidisciplinary care that these patients require. Effective management of these patients, and their orthopaedic injuries, requires a strong understanding of the pathophysiology of the response to trauma and indicators of patient status, as well as an appreciation for the dynamic nature of these parameters. Substantial progress in both clinical and basic science research in this area has advanced our understanding of these concepts and our approach to management of the polytraumatized patient. This article summarizes a symposium on this topic that was presented by an international panel of experts at the 2020 Virtual Annual Meeting of the Orthopaedic Trauma Association.
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    Role of p85α in neutrophil extra- and intracellular reactive oxygen species generation
    (Impact Journals, 2016-04-26) Li, Xing Jun; Deng, Lisa; Brandt, Stephanie L.; Goodwin, Charles B.; Ma, Peilin; Yang, Zhenyun; Mali, Raghu S.; Liu, Ziyue; Kapur, Reuben; Serezani, C. Henrique; Chan, Rebecca J.; Department of Pediatrics, IU School of Medicine
    Drug resistance is a growing problem that necessitates new strategies to combat pathogens. Neutrophil phagocytosis and production of intracellular ROS, in particular, has been shown to cooperate with antibiotics in the killing of microbes. This study tested the hypothesis that p85α, the regulatory subunit of PI3K, regulates production of intracellular ROS. Genetic knockout of p85α in mice caused decreased expression of catalytic subunits p110α, p110β, and p110δ, but did not change expression levels of the NADPH oxidase complex subunits p67phox, p47phox, and p40phox. When p85α, p55α, and p50α (all encoded by Pik3r1) were deleted, there was an increase in intracellular ROS with no change in phagocytosis in response to both Fcγ receptor and complement receptor stimulation. Furthermore, the increased intracellular ROS correlated with significantly improved neutrophil killing of both methicillin-susceptible and methicillin-resistant S. aureus. Our findings suggest inhibition of p85α as novel approach to improving the clearance of resistant pathogens.