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Somelar-Duracz K, Jürgenson M, Viil J, Zharkovsky A, Jaako K. 'Unpredictable chronic mild stress does not exacerbate memory impairment or altered neuronal and glial plasticity in the hippocampus of middle-aged vitamin D deficient mice'. Eur J Neurosci 2024; 59:1696-1722. [PMID: 38269959 DOI: 10.1111/ejn.16256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 12/10/2023] [Accepted: 01/02/2024] [Indexed: 01/26/2024]
Abstract
Vitamin D deficiency is a worldwide health concern, especially in the elderly population. Much remains unknown about the relationship between vitamin D deficiency (VDD), stress-induced cognitive dysfunctions and depressive-like behaviour. In this study, 4-month-old male C57Bl/6J mice were fed with control or vitamin D free diet for 6 months, followed by unpredictable chronic stress (UCMS) for 8 weeks. VDD induced cognitive impairment and reduced grooming behaviour, but did not induce depressive-like behaviour. While UCMS in vitamin D sufficient mice induced expected depressive-like phenotype and impairments in the contextual fear memory, chronic stress did not manifest as an additional risk factor for memory impairments and depressive-like behaviour in VDD mice. In fact, UCMS restored self-care behaviour in VDD mice. At the histopathological level, VDD mice exhibited cell loss in the granule cell layer, reduced survival of newly generated cells, accompanied with an increased number of apoptotic cells and alterations in glial morphology in the hippocampus; however, these effects were not exacerbated by UCMS. Interestingly, UCMS reversed VDD induced loss of microglial cells. Moreover, tyrosine hydroxylase levels decreased in the striatum of VDD mice, but not in stressed VDD mice. These findings indicate that long-term VDD in adulthood impairs cognition but does not augment behavioural response to UCMS in middle-aged mice. While VDD caused cell loss and altered glial response in the DG of the hippocampus, these effects were not exacerbated by UCMS and could contribute to mechanisms regulating altered stress response.
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Affiliation(s)
- Kelli Somelar-Duracz
- Institute of Biomedicine and Translational Medicine, Department of Pharmacology, University of Tartu, Tartu, Estonia
| | - Monika Jürgenson
- Institute of Biomedicine and Translational Medicine, Department of Pharmacology, University of Tartu, Tartu, Estonia
| | - Janeli Viil
- Institute of Biomedicine and Translational Medicine, Department of Pharmacology, University of Tartu, Tartu, Estonia
| | - Alexander Zharkovsky
- Institute of Biomedicine and Translational Medicine, Department of Pharmacology, University of Tartu, Tartu, Estonia
| | - Külli Jaako
- Institute of Biomedicine and Translational Medicine, Department of Pharmacology, University of Tartu, Tartu, Estonia
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Li W, Tang T, Yao S, Zhong S, Fan Q, Zou T. Low-dose Lipopolysaccharide Alleviates Spinal Cord Injury-induced Neuronal Inflammation by Inhibiting microRNA-429-mediated Suppression of PI3K/AKT/Nrf2 Signaling. Mol Neurobiol 2024; 61:294-307. [PMID: 37605094 DOI: 10.1007/s12035-023-03483-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 07/05/2023] [Indexed: 08/23/2023]
Abstract
This study investigated the impact of low-dose lipopolysaccharide (LPS) on spinal cord injury (SCI) and the potential molecular mechanism. Rats were randomly assigned to four groups: Sham, SCI, SCI + LPS, and SCI + LPS + agomir. Allen's weight-drop method was used to establish an in vivo SCI model. The Basso Bcattie Bresnahan rating scale was employed to monitor locomotor function. An in vitro SCI model was constructed by subjecting PC12 cells to oxygen and glucose deprivation/ reoxygenation (OGD/R). Enzyme-linked immunosorbent assay (ELISA) was applied for the determination interleukin (IL)-1β and IL-6. The dual luciferase reporter assay was used to validate the targeting of microRNA (miR)-429 with PI3K. Immunohistochemical staining was used to assess the expression of PI3K, phosphorylated AKT and Nrf2 proteins. The Nrf2-downstream anti-oxidative stress proteins, OH-1 and NQO1, were detected by western blot assay. MiR-429 expression was detected by fluorescence in situ hybridization and real-time quantitative reverse transcription PCR. In vitro, low-dose LPS decreased miR-429 expression, activated PI3K/AKT/Nrf2, inhibited oxidative stress and inflammation, and attenuated SCI. MiR-429 was found to target and negatively regulate PI3K. Inhibition of miR-429 suppressed low-dose LPS-mediated oxidative stress and inflammation via activation of the PI3K/AKT/Nrf2 pathway. In vivo, miR-429 was detectable in neurons. Inhibition of miR-429 blocked low-dose LPS-mediated oxidative stress and inflammation via activation of the PI3K/AKT/Nrf2 pathway. Overall, low-dose LPS was found to alleviate SCI-induced neuronal oxidative stress and inflammatory response by down-regulating miR-429 to activate the PI3K/AKT/Nrf2 pathway.
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Affiliation(s)
- Weichao Li
- Department of Orthopedic Surgery, The First People's Hospital of Yunnan province, Affiliated Hospital of Kunming University of Science and Technology, Kunming, 650032, China
- Faculty of Medical Science, Kunming University of Science and Technology, Kunming, 650500, China
- Yunnan Key Laboratory of Digital Orthopaedics, Kunming, 650032, China
| | - Tao Tang
- Faculty of Medical Science, Kunming University of Science and Technology, Kunming, 650500, China
| | - Shaoping Yao
- Department of Orthopedic Surgery, The First People's Hospital of Yunnan province, Affiliated Hospital of Kunming University of Science and Technology, Kunming, 650032, China
- Yunnan Key Laboratory of Digital Orthopaedics, Kunming, 650032, China
| | - Shixiao Zhong
- Faculty of Medical Science, Kunming University of Science and Technology, Kunming, 650500, China
| | - Qianbo Fan
- Faculty of Medical Science, Kunming University of Science and Technology, Kunming, 650500, China
| | - Tiannan Zou
- Department of Orthopedic Surgery, The First People's Hospital of Yunnan province, Affiliated Hospital of Kunming University of Science and Technology, Kunming, 650032, China.
- Yunnan Key Laboratory of Digital Orthopaedics, Kunming, 650032, China.
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Lajqi T, Köstlin-Gille N, Bauer R, Zarogiannis SG, Lajqi E, Ajeti V, Dietz S, Kranig SA, Rühle J, Demaj A, Hebel J, Bartosova M, Frommhold D, Hudalla H, Gille C. Training vs. Tolerance: The Yin/Yang of the Innate Immune System. Biomedicines 2023; 11:biomedicines11030766. [PMID: 36979747 PMCID: PMC10045728 DOI: 10.3390/biomedicines11030766] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/26/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023] Open
Abstract
For almost nearly a century, memory functions have been attributed only to acquired immune cells. Lately, this paradigm has been challenged by an increasing number of studies revealing that innate immune cells are capable of exhibiting memory-like features resulting in increased responsiveness to subsequent challenges, a process known as trained immunity (known also as innate memory). In contrast, the refractory state of endotoxin tolerance has been defined as an immunosuppressive state of myeloid cells portrayed by a significant reduction in the inflammatory capacity. Both training as well tolerance as adaptive features are reported to be accompanied by epigenetic and metabolic alterations occurring in cells. While training conveys proper protection against secondary infections, the induction of endotoxin tolerance promotes repairing mechanisms in the cells. Consequently, the inappropriate induction of these adaptive cues may trigger maladaptive effects, promoting an increased susceptibility to secondary infections—tolerance, or contribute to the progression of the inflammatory disorder—trained immunity. This review aims at the discussion of these opposing manners of innate immune and non-immune cells, describing the molecular, metabolic and epigenetic mechanisms involved and interpreting the clinical implications in various inflammatory pathologies.
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Affiliation(s)
- Trim Lajqi
- Department of Neonatology, Heidelberg University Children’s Hospital, D-69120 Heidelberg, Germany
- Correspondence: (T.L.); (C.G.)
| | - Natascha Köstlin-Gille
- Department of Neonatology, Heidelberg University Children’s Hospital, D-69120 Heidelberg, Germany
- Department of Neonatology, University of Tübingen, D-72076 Tübingen, Germany
| | - Reinhard Bauer
- Institute of Molecular Cell Biology, Jena University Hospital, D-07745 Jena, Germany
| | - Sotirios G. Zarogiannis
- Department of Physiology, School of Health Sciences, Faculty of Medicine, University of Thessaly, GR-41500 Larissa, Greece
| | - Esra Lajqi
- Department of Radiation Oncology, Heidelberg University Hospital, D-69120 Heidelberg, Germany
| | - Valdrina Ajeti
- Department of Pharmacy, Alma Mater Europaea—Campus College Rezonanca, XK-10000 Pristina, Kosovo
| | - Stefanie Dietz
- Department of Neonatology, Heidelberg University Children’s Hospital, D-69120 Heidelberg, Germany
- Department of Neonatology, University of Tübingen, D-72076 Tübingen, Germany
| | - Simon A. Kranig
- Department of Neonatology, Heidelberg University Children’s Hospital, D-69120 Heidelberg, Germany
| | - Jessica Rühle
- Department of Neonatology, University of Tübingen, D-72076 Tübingen, Germany
| | - Ardian Demaj
- Faculty of Medical Sciences, University of Tetovo, MK-1200 Tetova, North Macedonia
| | - Janine Hebel
- Department of Neonatology, University of Tübingen, D-72076 Tübingen, Germany
| | - Maria Bartosova
- Center for Pediatric and Adolescent Medicine Heidelberg, University of Heidelberg, D-69120 Heidelberg, Germany
| | - David Frommhold
- Klinik für Kinderheilkunde und Jugendmedizin, D-87700 Memmingen, Germany
| | - Hannes Hudalla
- Department of Neonatology, Heidelberg University Children’s Hospital, D-69120 Heidelberg, Germany
| | - Christian Gille
- Department of Neonatology, Heidelberg University Children’s Hospital, D-69120 Heidelberg, Germany
- Correspondence: (T.L.); (C.G.)
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Wang T, Hu Y, Dusi S, Qi F, Sartoris S, Ugel S, De Sanctis F. "Open Sesame" to the complexity of pattern recognition receptors of myeloid-derived suppressor cells in cancer. Front Immunol 2023; 14:1130060. [PMID: 36911674 PMCID: PMC9992799 DOI: 10.3389/fimmu.2023.1130060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 01/30/2023] [Indexed: 02/24/2023] Open
Abstract
Pattern recognition receptors are primitive sensors that arouse a preconfigured immune response to broad stimuli, including nonself pathogen-associated and autologous damage-associated molecular pattern molecules. These receptors are mainly expressed by innate myeloid cells, including granulocytes, monocytes, macrophages, and dendritic cells. Recent investigations have revealed new insights into these receptors as key players not only in triggering inflammation processes against pathogen invasion but also in mediating immune suppression in specific pathological states, including cancer. Myeloid-derived suppressor cells are preferentially expanded in many pathological conditions. This heterogeneous cell population includes immunosuppressive myeloid cells that are thought to be associated with poor prognosis and impaired response to immune therapies in various cancers. Identification of pattern recognition receptors and their ligands increases the understanding of immune-activating and immune-suppressive myeloid cell functions and sheds light on myeloid-derived suppressor cell differences from cognate granulocytes and monocytes in healthy conditions. This review summarizes the different expression, ligand recognition, signaling pathways, and cancer relations and identifies Toll-like receptors as potential new targets on myeloid-derived suppressor cells in cancer, which might help us to decipher the instruction codes for reverting suppressive myeloid cells toward an antitumor phenotype.
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Affiliation(s)
- Tian Wang
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Yushu Hu
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Silvia Dusi
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Fang Qi
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Silvia Sartoris
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Stefano Ugel
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Francesco De Sanctis
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
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Pechacek KM, Vonder Haar C. Chronic lipopolysaccharide impairs motivation when delivered to the ventricles, but not when delivered peripherally in male rats. Physiol Behav 2022; 257:113998. [PMID: 36257462 DOI: 10.1016/j.physbeh.2022.113998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 09/18/2022] [Accepted: 10/13/2022] [Indexed: 11/05/2022]
Abstract
Increased neuroinflammation relative to controls is observed in major depression. Moreover, depressive disorders are significantly elevated in conditions which increase neuroinflammation (e.g., brain injury, Parkinson's disease, Alzheimer's disease). To better understand the relationship between neuroinflammation and depression, additional research is needed. The current set of studies made use of the progressive ratio (PR) task in male rats, a stable measure of motivation which can be evaluated daily and thus is ideally suited for examining a potential role for chronic neuroinflammation in depressive-like behavior. Lipopolysaccharide (LPS) was used to induce an inflammatory response. Experiment 1 confirmed prior acute LPS administration experiments for sensitivity of the PR task, with a large effect at 2 mg/kg, a partial effect at 1 mg/kg, and no effect at 0.5 mg/kg. Experiment 2 evaluated a dose-response of continuous s.c. LPS infusion but found no significant elevation in brain cytokines after 14 days at any doses of 0.1, 0.5, 1, or 2 mg/kg/week. Experiment 3 assessed motivation during continuous s.c. infusion of a large 5 mg/kg/week LPS dose and found no significant impairments in motivation, but transient decreases in rates of lever pressing (i.e., only motoric deficits). Experiment 4 measured motivation during continuous ICV infusion of 10.5 μg/kg/week LPS and found significantly decreased motivation without changes to rates of lever pressing (i.e., only motivational deficits). Together these results suggest that the PR task is efficient for evaluating models of chronic inflammation, and that the adaptive response to chronic LPS exposure, even when delivered centrally, may necessitate alternative strategies for generating long-term neuroinflammation.
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Affiliation(s)
- Kristen M Pechacek
- Injury and Recovery Laboratory, Department of Neuroscience, Ohio State University, Columbus, OH, USA
| | - Cole Vonder Haar
- Injury and Recovery Laboratory, Department of Neuroscience, Ohio State University, Columbus, OH, USA.
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Pal R, Bradford BM, Mabbott NA. Prion Disease in the Central Nervous System. Front Cell Neurosci 2022; 16:918883. [PMID: 35875357 PMCID: PMC9302378 DOI: 10.3389/fncel.2022.918883] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 06/13/2022] [Indexed: 01/15/2023] Open
Abstract
Prion diseases such as Creutzfeldt-Jakob disease in humans, bovine spongiform encephalopathy in cattle, and scrapie in sheep, are infectious and chronic neurodegenerative diseases to which there are no cures. Infection with prions in the central nervous system (CNS) ultimately causes extensive neurodegeneration, and this is accompanied by prominent microglial and astrocytic activation in affected regions. The microglia are the CNS macrophages and help maintain neuronal homeostasis, clear dead or dying cells and provide defense against pathogens. The microglia also provide neuroprotection during CNS prion disease, but their pro-inflammatory activation may exacerbate the development of the neuropathology. Innate immune tolerance induced by consecutive systemic bacterial lipopolysaccharide (LPS) treatment can induce long-term epigenetic changes in the microglia in the brain that several months later can dampen their responsiveness to subsequent LPS treatment and impede the development of neuritic damage in a transgenic mouse model of Alzheimer’s disease-like pathology. We therefore reasoned that innate immune tolerance in microglia might similarly impede the subsequent development of CNS prion disease. To test this hypothesis groups of mice were first infected with prions by intracerebral injection, and 35 days later given four consecutive systemic injections with LPS to induce innate immune tolerance. Our data show that consecutive systemic LPS treatment did not affect the subsequent development of CNS prion disease. Our data suggests innate immune tolerance in microglia does not influence the subsequent onset of prion disease-induced neuropathology in mice, despite previously published evidence of this effect in an Alzheimer’s disease mouse model.
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7
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Lajqi T, Frommhold D, Gille C, Hudalla H. Induction of memory-like adaptive responses in murine neutrophils in vitro. Cell Immunol 2022; 376:104535. [DOI: 10.1016/j.cellimm.2022.104535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 04/29/2022] [Accepted: 04/29/2022] [Indexed: 01/02/2023]
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Sharma R, Casillas-Espinosa PM, Dill LK, Rewell SSJ, Hudson MR, O'Brien TJ, Shultz SR, Semple BD. Pediatric traumatic brain injury and a subsequent transient immune challenge independently influenced chronic outcomes in male mice. Brain Behav Immun 2022; 100:29-47. [PMID: 34808288 DOI: 10.1016/j.bbi.2021.11.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 10/27/2021] [Accepted: 11/15/2021] [Indexed: 01/30/2023] Open
Abstract
Traumatic brain injury (TBI) is a major contributor to death and disability worldwide. Children are at particularly high risk of both sustaining a TBI and experiencing serious long-term consequences, such as cognitive deficits, mental health problems and post-traumatic epilepsy. Severe TBI patients are highly susceptible to nosocomial infections, which are mostly acquired within the first week of hospitalization post-TBI. Yet the potential chronic impact of such acute infections following pediatric TBI remains unclear. In this study, we hypothesized that a peripheral immune challenge, such as lipopolysaccharide (LPS)-mimicking a hospital-acquired infection-would worsen inflammatory, neurobehavioral, and seizure outcomes after experimental pediatric TBI. To test this, three-week old male C57Bl/6J mice received a moderate controlled cortical impact or sham surgery, followed by 1 mg/kg i.p. LPS (or 0.9% saline vehicle) at 4 days TBI. Mice were randomized to four groups; sham-saline, sham-LPS, TBI-saline or TBI-LPS (n = 15/group). Reduced general activity and increased anxiety-like behavior were observed within 24 h in LPS-treated mice, indicating a transient sickness response. LPS-treated mice also exhibited a reduction in body weights, which persisted chronically. From 2 months post-injury, mice underwent a battery of tests for sensorimotor, cognitive, and psychosocial behaviors. TBI resulted in hyperactivity and spatial memory deficits, independent of LPS; whereas LPS resulted in subtle deficits in spatial memory retention. At 5 months post-injury, video-electroencephalographic recordings were obtained to evaluate both spontaneous seizure activity as well as the evoked seizure response to pentylenetetrazol (PTZ). TBI increased susceptibility to PTZ-evoked seizures; whereas LPS appeared to increase the incidence of spontaneous seizures. Post-mortem analyses found that TBI, but not LPS, resulted in robust glial reactivity and loss of cortical volume. A TBI × LPS interaction in hippocampal volume suggested that TBI-LPS mice had a subtle increase in ipsilateral hippocampus tissue loss; however, this was not reflected in neuronal cell counts. Both TBI and LPS independently had modest effects on chronic hippocampal gene expression. Together, contrary to our hypothesis, we observed minimal synergy between TBI and LPS. Instead, pediatric TBI and a subsequent transient immune challenge independently influenced chronic outcomes. These findings have implications for future preclinical modeling as well as acute post-injury patient management.
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Affiliation(s)
- Rishabh Sharma
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Pablo M Casillas-Espinosa
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia; Department of Neurology, Alfred Health, Prahran, VIC, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, VIC, Australia
| | - Larissa K Dill
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia; Department of Neurology, Alfred Health, Prahran, VIC, Australia
| | - Sarah S J Rewell
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia; Department of Neurology, Alfred Health, Prahran, VIC, Australia
| | - Matthew R Hudson
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Terence J O'Brien
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia; Department of Neurology, Alfred Health, Prahran, VIC, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, VIC, Australia
| | - Sandy R Shultz
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia; Department of Neurology, Alfred Health, Prahran, VIC, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, VIC, Australia
| | - Bridgette D Semple
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia; Department of Neurology, Alfred Health, Prahran, VIC, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, VIC, Australia.
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Lajqi T, Braun M, Kranig SA, Frommhold D, Pöschl J, Hudalla H. LPS Induces Opposing Memory-like Inflammatory Responses in Mouse Bone Marrow Neutrophils. Int J Mol Sci 2021; 22:ijms22189803. [PMID: 34575963 PMCID: PMC8469609 DOI: 10.3390/ijms22189803] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 08/23/2021] [Accepted: 09/07/2021] [Indexed: 01/03/2023] Open
Abstract
A growing body of evidence suggests that innate immune cells can respond in a memory-like (adaptive) fashion, which is referred to as trained immunity. Only few in vivo studies have shown training effects in neutrophils; however, no in vitro setup has been established to study the induction of trained immunity or tolerance in neutrophils by microbial agents. In light of their short lifespan (up to 48 h), we suggest to use the term trained sensitivity for neutrophils in an in vitro setting. Here, we firstly describe a feasible two-hit model, using different doses of lipopolysaccharide (LPS) in bone marrow neutrophils. We found that low doses (10 pg/mL) induce pro-inflammatory activation (trained sensitivity), whereas priming with high doses (100 ng/mL) leads to suppression of pro-inflammatory mediators such as TNF-α or IL-6 (tolerance) (p < 0.05). On a functional level, trained neutrophils displayed increased phagocytic activity and LFA-1 expression as well as migrational capacity and CD11a expression, whereas tolerant neutrophils show contrasting effects in vitro. Mechanistically, TLR4/MyD88/PI3Ks regulate the activation of p65, which controls memory-like responses in mouse bone marrow neutrophils (p < 0.05). Our results open a new window for further in vitro studies on memory-like inflammatory responses of short-lived innate immune cells such as neutrophils.
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Affiliation(s)
- Trim Lajqi
- Department of Neonatology, Heidelberg University Children’s Hospital, D-69120 Heidelberg, Germany; (T.L.); (M.B.); (S.A.K.); (D.F.); (J.P.)
| | - Maylis Braun
- Department of Neonatology, Heidelberg University Children’s Hospital, D-69120 Heidelberg, Germany; (T.L.); (M.B.); (S.A.K.); (D.F.); (J.P.)
| | - Simon Alexander Kranig
- Department of Neonatology, Heidelberg University Children’s Hospital, D-69120 Heidelberg, Germany; (T.L.); (M.B.); (S.A.K.); (D.F.); (J.P.)
| | - David Frommhold
- Department of Neonatology, Heidelberg University Children’s Hospital, D-69120 Heidelberg, Germany; (T.L.); (M.B.); (S.A.K.); (D.F.); (J.P.)
- Klinik für Kinderheilkunde und Jugendmedizin, D-87700 Memmingen, Germany
| | - Johannes Pöschl
- Department of Neonatology, Heidelberg University Children’s Hospital, D-69120 Heidelberg, Germany; (T.L.); (M.B.); (S.A.K.); (D.F.); (J.P.)
| | - Hannes Hudalla
- Department of Neonatology, Heidelberg University Children’s Hospital, D-69120 Heidelberg, Germany; (T.L.); (M.B.); (S.A.K.); (D.F.); (J.P.)
- Correspondence: ; Tel.: +49-6221-56-1983; Fax: +49-6221-56-5626
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Singh G, Segura BJ, Georgieff MK, Gisslen T. Fetal inflammation induces acute immune tolerance in the neonatal rat hippocampus. J Neuroinflammation 2021; 18:69. [PMID: 33706765 PMCID: PMC7953777 DOI: 10.1186/s12974-021-02119-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 02/24/2021] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Infants born preterm due to chorioamnionitis are frequently affected by a fetal inflammatory response syndrome (FIRS) and then by subsequent postnatal infections. FIRS and postnatal systemic inflammatory events independently contribute to poor neurocognitive outcomes of preterm infants. Developmental integrity of the hippocampus is crucial for intact neurocognitive outcomes in preterms and hippocampally dependent behaviors are particularly vulnerable to preterm systemic inflammation. How FIRS modulates the hippocampal immune response to acute postnatal inflammatory events is not well understood. METHODS Prenatal LPS exposed (FIRS) and control neonatal rats received i.p. LPS or saline at postnatal day (P) 5. On P7, immune response was evaluated in the hippocampus of four treatment groups by measuring gene expression of inflammatory mediators and cytosolic and nuclear NFκB pathway proteins. Microglial activation was determined by CD11b+ and Iba1+ immunohistochemistry (IHC) and inflammatory gene expression of isolated microglia. Astrocyte reactivity was measured using Gfap+ IHC. RESULTS Postnatal LPS resulted in a robust hippocampal inflammatory response. In contrast, FIRS induced by prenatal LPS attenuated the response to postnatal LPS exposure, evidenced by decreased gene expression of inflammatory mediators, decreased nuclear NFκB p65 protein, and fewer activated CD11b+ and Iba1+ microglia. Isolated microglia demonstrated inflammatory gene upregulation to postnatal LPS without evidence of immune tolerance by prenatal LPS. CONCLUSION Prenatal LPS exposure induced immune tolerance to subsequent postnatal LPS exposure in the hippocampus. Microglia demonstrate a robust inflammatory response to postnatal LPS, but only a partial immune tolerance response.
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Affiliation(s)
- Garima Singh
- Division of Neonatology, Department of Pediatrics, University of Minnesota, East Building MB630, 2450 Riverside Avenue, Minneapolis, MN, 55454, USA
| | - Bradley J Segura
- Division of Pediatric Surgery, Department of Surgery, University of Minnesota, East Building MB630, 2450 Riverside Avenue, Minneapolis, MN, 55454, USA
| | - Michael K Georgieff
- Division of Neonatology, Department of Pediatrics, University of Minnesota, East Building MB630, 2450 Riverside Avenue, Minneapolis, MN, 55454, USA
| | - Tate Gisslen
- Division of Neonatology, Department of Pediatrics, University of Minnesota, East Building MB630, 2450 Riverside Avenue, Minneapolis, MN, 55454, USA.
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