Deletion of G protein-coupled receptor 116 enhances neutrophil function and aggravates lung injury in mice
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PROVIDER: S-EPMC10311051 | biostudies-literature | 2022 Sep
REPOSITORIES: biostudies-literature
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Project description:Oxidative stress and inflammation are implicated in the development of sepsis-related acute lung injury (ALI). MicroRNA-1224-5p (miR-1224-5p) plays critical roles in regulating inflammatory response and reactive oxygen species (ROS) production. The present study is aimed at investigating the role and underlying mechanisms of miR-1224-5p in sepsis-related ALI. Mice were intratracheally injected with lipopolysaccharide (LPS, 5 mg/kg) for 12 h to induce sepsis-related ALI. To manipulate miR-1224-5p level, mice were intravenously injected with the agomir, antagomir, or matched controls for 3 consecutive days. Murine peritoneal macrophages were stimulated with LPS (100 ng/mL) for 6 h to further validate the role of miR-1224-5p in vitro. To inhibit adenosine 5'-monophosphate-activated protein kinase alpha (AMPKα) or peroxisome proliferator activated receptor-gamma (PPAR-γ), compound C or GW9662 was used in vivo and in vitro. We found that miR-1224-5p levels in lungs were elevated by LPS injection, and that the miR-1224-5p antagomir significantly alleviated LPS-induced inflammation, oxidative stress, and ALI in mice. Conversely, the miR-1224-5p agomir aggravated inflammatory response, ROS generation, and pulmonary dysfunction in LPS-treated mice. In addition, the miR-1224-5p antagomir reduced, while the miR-1224-5p agomir aggravated LPS-induced inflammation and oxidative stress in murine peritoneal macrophages. Further findings revealed that miR-1224-5p is directly bound to the 3'-untranslated regions of PPAR-γ and subsequently suppressed PPAR-γ/AMPKα axis, thereby aggravating LPS-induced ALI in vivo and in vitro. We demonstrate for the first time that endogenous miR-1224-5p is a critical pathogenic factor for inflammation and oxidative damage during LPS-induced ALI through inactivating PPAR-γ/AMPKα axis. Targeting miR-1224-5p may help to develop novel approaches to treat sepsis-related ALI.
| S-EPMC9256451 | biostudies-literature
Project description:BackgroundPlatelets store large amounts of serotonin that they release during thrombus formation or acute inflammation. This facilitates hemostasis and modulates the inflammatory response.MethodsInfarct size, heart function, and inflammatory cell composition were analyzed in mouse models of myocardial reperfusion injury with genetic and pharmacological depletion of platelet serotonin. These studies were complemented by in vitro serotonin stimulation assays of platelets and leukocytes in mice and men, and by measuring plasma serotonin levels and leukocyte activation in patients with acute coronary syndrome.ResultsPlatelet-derived serotonin induced neutrophil degranulation with release of myeloperoxidase and hydrogen peroxide (H2O2) and increased expression of membrane-bound leukocyte adhesion molecule CD11b, leading to enhanced inflammation in the infarct area and reduced myocardial salvage. In patients hospitalized with acute coronary syndrome, plasmatic serotonin levels correlated with CD11b expression on neutrophils and myeloperoxidase plasma levels. Long-term serotonin reuptake inhibition-reported to protect patients with depression from cardiovascular events-resulted in the depletion of platelet serotonin stores in mice. These mice displayed a reduction in neutrophil degranulation and preserved cardiac function. In line, patients with depression using serotonin reuptake inhibition, presented with suppressed levels of CD11b surface expression on neutrophils and lower myeloperoxidase levels in blood.ConclusionsTaken together, we identify serotonin as a potent therapeutic target in neutrophil-dependent thromboinflammation during myocardial reperfusion injury.
| S-EPMC6370531 | biostudies-literature
Project description:BackgroundCardiac dysfunction is one of the most common complications of sepsis and is associated with the adverse outcomes and high mortality of sepsis patients. IL-12p40, the common subunit of IL-12 and IL-23, has been shown to be involved in a variety of inflammation-related diseases, such as psoriasis and inflammatory bowel disease. However, the role of IL-12p40 in lipopolysaccharide (LPS)-induced cardiac dysfunction remains obscure. This study aimed to explore the role of IL-12p40 in LPS-induced cardiac dysfunction and its potential mechanisms.MethodsIn this study, mice were treated with LPS and the cardiac expression of IL-12p40 was determined. Then, IL-12p40-/- mice were used to detect the role and mechanisms of IL-12p40 in LPS-induced cardiac injury. In addition, monocytes were adoptively transferred to IL-12p40-/- mice to explore their effects on LPS-induced cardiac dysfunction.ResultsThe results showed that cardiac IL-12p40 expression was significantly increased after treated with LPS. In addition, IL-12p40 deletion significantly aggravated LPS-induced cardiac dysfunction, evidenced by the increased serum levels of cardiomyocyte injury markers and heart injury scores, as well as by the deteriorated cardiac function. Moreover, IL-12p40 deletion increased LPS-induced monocyte accumulation and cardiac expression of inflammatory cytokines, as well as enhanced the activation of the NF-κB and MAPK pathways. Furthermore, adoptive transfer WT mouse monocytes to IL-12p40-/- mice alleviated LPS-induced cardiac dysfunction and decreased the phosphorylation of p65.ConclusionIL-12p40 deletion significantly aggravated LPS-induced cardiac injury and cardiac dysfunction in mice by regulating the NF-κB and MAPK signaling pathways, and this process was related to monocytes. Therefore, IL-12p40 show a protective role in SIC, and IL-12p40 deficiency or anti-IL-12p40 monoclonal antibodies may be detrimental to patients with SIC.
| S-EPMC9523082 | biostudies-literature
Project description:BackgroundForty percent of critically ill trauma patients will develop an infectious complication. Pneumonia is the most common cause of death of trauma patients surviving their initial insult. We previously demonstrated that polytrauma (PT), defined as two or more severe injuries in at least two areas of the body, induces emergency hematopoiesis characterized by accelerated myelopoiesis in the bone marrow and increased myeloid cell frequency in the peripheral tissues. We hypothesized that PT alone induces priming of neutrophils, resulting in hyperactivation upon secondary exposure to bacteria and causing acute lung injury and increased susceptibility to secondary exposure to Pseudomonas aeruginosa pneumonia.MethodsC57BL/6 mice were subjected to PT consisting of a lower extremity pseudofracture, liver crush injury, and 15% blood-volume hemorrhage. Pneumonia was induced by intratracheal injection of 5 × 106 CFU live P. aeruginosa or 1 × 107 of heat-killed P. aeruginosa (HKPA). For reactive oxygen species (ROS), studies polymorphonuclear neutrophils (PMNs) were isolated by immunomagnetic bead negative selection and stimulated ex-vivo with HKPA. Reactive oxygen species production was measured by immunofluorescence. For histology, lung sections were stained by hematoxylin-eosin and analyzed by a blinded grader.ResultsPolytrauma induced persistent changes in immune function at baseline and to secondary infection. Pneumonia after injury resulted in increased mortality (60% vs. 5% p < 0.01). Blood neutrophils from PT mice had higher resting (unstimulated) ROS production than in naive animals (p < 0.02) demonstrating priming of the neutrophils following PT. After intratracheal HKPA injection, bronchoalveolar lavage PMNs from injured mice had higher ROS production compared with naive mice (p < 0.01), demonstrating an overexuberant immunopathologic response of neutrophils following PT.ConclusionPolytrauma primes neutrophils and causes immunopathologic PMN ROS production, increased lung injury and susceptibility to secondary bacterial pneumonia. These results suggest that trauma-induced immune dysfunction can cause immunopathologic response to secondary infection and suggests neutrophil-mediated pulmonary damage as a therapeutic target for posttrauma pneumonia.
| S-EPMC8932930 | biostudies-literature
Project description:Krüppel-like factors (KLFs) belong to the zinc finger family of transcription factors, and their function in the CNS is largely unexplored. KLF11 is a member of the KLF family, and we have previously demonstrated that peroxisome proliferator-activated receptor gamma-mediated cerebral protection during ischemic insults needs recruitment of KLF11 as its critical coactivator. Here, we sought to determine the role of KLF11 itself in cerebrovascular function and the pathogenesis of ischemic stroke. Transient middle cerebral artery occlusion (MCAO) was performed in KLF11 knockout and wild-type control mice, and brain infarction was analyzed by TTC staining. BBB integrity was assessed by using Evans Blue and TMR-Dextran extravasation assays. KLF11 KO mice exhibited significantly larger brain infarction and poorer neurological outcomes in response to ischemic insults. Genetic deficiency of KLF11 in mice also significantly aggravated ischemia-induced BBB disruption by increasing cerebrovascular permeability and edema. Mechanistically, KLF11 was found to directly regulate IL-6 in the brains of ischemic mice. These findings suggest that KLF11 acts as a novel protective factor in ischemic stroke. Elucidating the functional importance of KLF11 in ischemia may lead us to discover novel pharmacological targets for the development of effective therapies against ischemic stroke.
| S-EPMC5660934 | biostudies-literature
Project description:BackgroundThe long-term functional recovery of traumatic brain injury (TBI) is hampered by pathological events, such as parenchymal neuroinflammation, neuronal death, and white matter injury. Krüppel-like transcription factor 11 (KLF 11) belongs to the zinc finger family of transcription factors and actively participates in various pathophysiological processes in neurological disorders. Up to now, the role and molecular mechanisms of KLF11 in regulating the pathogenesis of brain trauma is poorly understood.MethodsKLF11 knockout (KO) and wild-type (WT) mice were subjected to experimental TBI, and sensorimotor and cognitive functions were evaluated by rotarod, adhesive tape removal, foot fault, water maze, and passive avoidance tests. Brain tissue loss/neuronal death was examined by MAP2 and NeuN immunostaining, and Cresyl violet staining. White matter injury was assessed by Luxol fast blue staining, and also MBP/SMI32 and Caspr/Nav1.6 immunostaining. Activation of cerebral glial cells and infiltration of blood-borne immune cells were detected by GFAP, Iba-1/CD16/32, Iba-1/CD206, Ly-6B, and F4/80 immunostaining. Brian parenchymal inflammatory cytokines were measured with inflammatory array kits.ResultsGenetic deletion of KLF11 worsened brain trauma-induced sensorimotor and cognitive deficits, brain tissue loss and neuronal death, and white matter injury in mice. KLF11 genetic deficiency in mice also accelerated post-trauma astrocytic activation, promoted microglial polarization to a pro-inflammatory phenotype, and increased the infiltration of peripheral neutrophils and macrophages into the brain parenchyma. Mechanistically, loss-of-KLF11 function was found to directly increase the expression of pro-inflammatory cytokines in the brains of TBI mice.ConclusionKLF11 acts as a novel protective factor in TBI. KLF11 genetic deficiency in mice aggravated the neuroinflammatory responses, grey and white matter injury, and impaired long-term sensorimotor and cognitive recovery. Elucidating the functional importance of KLF11 in TBI may lead us to discover novel pharmacological targets for the development of effective therapies against brain trauma.
| S-EPMC9675068 | biostudies-literature
Project description:Traumatic brain injury (TBI) is a significant global health concern that often results in death or disability, and effective pharmacological treatments are lacking. G protein-coupled receptor 56 (GPR56), a potential drug target, is crucial for neuronal and glial cell function and therefore plays important roles in various neurological diseases. Here, we investigated the potential role and mechanism of GPR56 in TBI-related damage to gain new insights into the pharmacological treatment of TBI. Our study revealed that TBI caused a significant decrease in GPR56 expression and that the deletion of Gpr56 exacerbated neurological function deficits and blood‒brain barrier (BBB) damage following TBI. Additionally, Gpr56 deletion led to increased microgliosis, increased infiltration of peripheral T cells and macrophages, and increased release of cerebral inflammatory cytokines and chemokines after TBI. Furthermore, Gpr56 deletion induced neuronal apoptosis, impaired autophagy, and exacerbated neurological function deficits through microglial-to-neuronal CCR5 signaling after TBI. Overall, these results indicate that Gpr56 knockout exacerbates neurological deficits, neuroinflammation and neuronal apoptosis following TBI through microglial CCL3/4/5 upregulation targeted to CCR5, which indicates that GRP56 may be a potential new pharmacological target for TBI.
| S-EPMC11910551 | biostudies-literature
Project description:BackgroundAcute lung injury (ALI) is distinguished by exaggerated neutrophil extracellular traps (NETs), elevated clinical mortality rates, and a paucity of targeted therapeutic interventions. The Gαq/11 protein, a member of the G protein subfamily, is an effective intervention target for a variety of diseases, but little is known about its role in ALI.MethodsIn this study, a murine model of ALI induced by lipopolysaccharide (LPS) was utilized, employing myeloid cell-specific Gna11 knockout mice. The pulmonary pathology of mice was assessed and the lung samples were collected for immunofluorescence staining and RNA-sequencing analysis to elucidate the impact and underlying mechanisms of Gαq/11 in ALI. Mouse bone marrow-derived neutrophils were isolated and cultured for live-cell imaging to investigate the in vitro effects of Gαq/11.ResultsThe expression of Gαq/11 was found to be upregulated in the lung tissues of mice with ALI, coinciding with the increased expression of inflammatory genes. Myeloid cell-specific Gna11 deficience attenuated LPS-induced lung injury and the formation of NETs in mice. Mechanistically, Gαq/11 facilitates NETosis by promoting the activation of the endoplasmic reticulum (ER) stress sensor IRE1α in neutrophils and mediating the production of mitochondrial reactive oxygen species (mitoROS). Pharmacological inhibition of Gαq/11 using YM-254,890 was shown to reduce NETs formation and lung injury in mice.ConclusionsThe upregulation of Gαq/11 exacerbates ALI through the promotion of ER stress-mediated NETosis. Consequently, Gαq/11 represents a potential therapeutic target for the treatment of ALI.
| S-EPMC11841161 | biostudies-literature
Project description:Intercellular transfer of microRNAs can mediate communication between critical effector cells. We hypothesized that transfer of neutrophil-derived microRNAs to pulmonary epithelial cells could alter mucosal gene expression during acute lung injury. Pulmonary-epithelial microRNA profiling during coculture of alveolar epithelial cells with polymorphonuclear neutrophils (PMNs) revealed a selective increase in lung epithelial cell expression of microRNA-223 (miR-223). Analysis of PMN-derived supernatants showed activation-dependent release of miR-223 and subsequent transfer to alveolar epithelial cells during coculture in vitro or after ventilator-induced acute lung injury in mice. Genetic studies indicated that miR-223 deficiency was associated with severe lung inflammation, whereas pulmonary overexpression of miR-223 in mice resulted in protection during acute lung injury induced by mechanical ventilation or by infection with Staphylococcus aureus Studies of putative miR-223 gene targets implicated repression of poly(adenosine diphosphate-ribose) polymerase-1 (PARP-1) in the miR-223-dependent attenuation of lung inflammation. Together, these findings suggest that intercellular transfer of miR-223 from neutrophils to pulmonary epithelial cells may dampen acute lung injury through repression of PARP-1.
| S-EPMC5842431 | biostudies-literature
Project description:Neutropenia and related infections are the most important dose-limiting toxicities in anticancer chemotherapy and radiotherapy. In this study, we explored a new strategy for augmenting host defense in neutropenia-related pneumonia. Phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P(3)) signaling in neutrophils was elevated by depleting PTEN, a phosphatidylinositol 3'-phosphatase that hydrolyzes PtdIns(3,4,5)P(3). In myeloid-specific PTEN knockout mice, significantly more neutrophils were recruited to the inflamed lungs during neutropenia-associated pneumonia. Using an adoptive transfer technique, we demonstrated that this enhancement could be caused directly by PTEN depletion in neutrophils. In addition, disruption of PTEN increased the recruitment of macrophages and elevated proinflammatory cytokines/chemokine levels in the inflamed lungs, which could also be responsible for the enhanced neutrophil recruitment. Depleting PTEN also significantly delayed apoptosis and enhanced the bacteria-killing capability of the recruited neutrophils. Finally, we provide direct evidence that enhancement of neutrophil function by elevating PtdIns(3,4,5)P(3) signaling can alleviate pneumonia-associated lung damage and decrease pneumonia-elicited mortality. Collectively, these results not only provide insight into the mechanism of action of PTEN and PtdIns(3,4,5)P(3) signaling pathway in modulating neutrophil function during lung infection and inflammation, but they also establish PTEN and related pathways as potential therapeutic targets for treating neutropenia-associated pneumonia.
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