scholarly journals Susceptibility rhythm to bacterial endotoxin in myeloid clock-knockout mice

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Veronika Lang ◽  
Sebastian Ferencik ◽  
Bharath Ananthasubramaniam ◽  
Achim Kramer ◽  
Bert Maier
Keyword(s):  
Knockout Mice ◽  
Endotoxic Shock ◽  
Time Of Day ◽  
Conditional Knockout ◽  
Constant Darkness ◽  
Immune Functions ◽  
Lps Challenge ◽  
Circadian Time ◽  
Tnf Α ◽  
Circadian Physiology

Local circadian clocks are active in most cells of our body. However, their impact on circadian physiology is still under debate. Mortality by endotoxic (LPS) shock is highly time-of-day dependent and local circadian immune function such as the cytokine burst after LPS challenge has been assumed to be causal for the large differences in survival. Here, we investigate the roles of light and myeloid clocks on mortality by endotoxic shock. Strikingly, mice in constant darkness (DD) show a three-fold increased susceptibility to LPS as compared to mice in light-dark conditions. Mortality by endotoxic shock as a function of circadian time is independent of light-dark cycles as well as myeloid CLOCK or BMAL1 as demonstrated in conditional knockout mice. Unexpectedly, despite the lack of a myeloid clock these mice still show rhythmic patterns of pro- and anti-inflammatory cytokines such as TNF,α MCP-1, IL-18 and IL-10 in peripheral blood as well as time-of-day and site dependent traffc of myeloid cells. We speculate that systemic time-cues are sufficient to orchestrate innate immune response to LPS by driving immune functions such as cell traffcking and cytokine expression.

scholarly journals Susceptibility rhythm to bacterial endotoxin in myeloid clock-knockout mice

2019 ◽  
Author(s):  
Veronika Lang ◽  
Sebastian Ferencik ◽  
Bharath Ananthasubramaniam ◽  
Achim Kramer ◽  
Bert Maier
Keyword(s):  
Knockout Mice ◽  
Endotoxic Shock ◽  
Time Of Day ◽  
Conditional Knockout ◽  
Constant Darkness ◽  
Cell Trafficking ◽  
Immune Functions ◽  
Lps Challenge ◽  
Circadian Time ◽  
Circadian Physiology

AbstractLocal circadian clocks are active in most cells of our body. However, their impact on circadian physiology is still under debate. Mortality by endotoxic (LPS) shock is highly time-of-day dependent and local circadian immune function such as the cytokine burst after LPS challenge has been assumed to be causal for the large differences in survival. Here, we investigate the roles of light and myeloid clocks on mortality by endotoxic shock. Strikingly, mice in constant darkness (DD) show a three-fold increased susceptibility to LPS as compared to mice in light-dark conditions. Mortality by endotoxic shock as a function of circadian time is independent of light-dark cycles as well as myeloid CLOCK or BMAL1 as demonstrated in conditional knockout mice. Unexpectedly, despite the lack of a myeloid clock these mice still show rhythmic patterns of pro- and anti-inflammatory cytokines such as TNFα, MCP-1, IL-18 and IL-10 in peripheral blood as well as time-of-day and site dependent traffic of myeloid cells. We speculate that systemic time-cues are sufficient to orchestrate innate immune response to LPS by driving immune functions such as cell trafficking and cytokine expression.

Pleiotropic functions of TNF-α determine distinct IKKβ-dependent hepatocellular fates in response to LPS

2007 ◽  
Vol 292 (1) ◽  
pp. G242-G252 ◽  
Author(s):  
Rana Dajani ◽  
Salih Sanlioglu ◽  
Yulong Zhang ◽  
Qiang Li ◽  
Martha M. Monick ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Viral Vectors ◽  
Endotoxic Shock ◽  
Lethal Dose ◽  
Dominant Negative ◽  
Endotoxin Challenge ◽  
Lps Challenge ◽  
Differential Outcomes ◽  
Tnf Α ◽  
Pleiotropic Functions

TNF-α influences morbidity and mortality during the course of endotoxemia. However, the complex pleiotropic functions of TNF-α remain poorly understood. We evaluated how hepatic induction of NF-κB and TNF-α influence survival and hepatocellular death in a lethal murine model of endotoxic shock. Using dominant-negative viral vectors to inhibit the IKK complex, we demonstrate through this study that the liver is a major source of TNF-α during the course of lethal endotoxemia and that IKKβ (but not IKKα) is predominantly responsible for activating NF-κB and TNF-α in the liver after LPS administration. Using TNF-α knockout mice and hepatic-specific inhibition of IKKβ, we demonstrate that the status of TNF-α and NF-κB balances necrotic and apoptotic fates of hepatocytes in the setting of endotoxemia. In the presence of TNF-α, inhibiting hepatic IKKβ resulted in increased survival, reduced serum proinflammatory cytokines, and reduced hepatocyte necrosis in response to a lethal dose of endotoxin. In contrast, inhibiting hepatic IKKβ in TNF-α knockout mice resulted in decreased survival and increased caspase 3-mediated hepatocyte apoptosis after endotoxin challenge, despite a reduced proinflammatory cytokine response. In the presence of TNF-α, NF-κB-dependent hepatocellular necrosis predominated, while in the absence of TNF-α, NF-κB primarily influenced apoptotic fate of hepatocytes. Changes in JNK phosphorylation after LPS challenge were also dynamically affected by both IKKβ and TNF-α; however, this pathway could not solely explain the differential outcomes in hepatocellular fates. In conclusion, our studies demonstrate that induction of NF-κB and TNF-α balances protective (antiapoptotic) and detrimental (proinflammatory) pathways to determine hepatocellular fates during endotoxemia.

scholarly journals A conserved long noncoding RNA, GAPLINC, modulates the immune response during endotoxic shock

2021 ◽  
Vol 118 (7) ◽  
pp. e2016648118
Author(s):  
Apple Cortez Vollmers ◽  
Sergio Covarrubias ◽  
Daisy Kuang ◽  
Aaron Shulkin ◽  
Justin Iwuagwu ◽  
...  
Keyword(s):  
Immune Response ◽  
Knockout Mice ◽  
Noncoding Rna ◽  
Target Genes ◽  
Blood Clot ◽  
Multiorgan Failure ◽  
Endotoxic Shock ◽  
Negative Regulator ◽  
Inflammatory Genes ◽  
Lps Challenge

Recent studies have identified thousands of long noncoding RNAs (lncRNAs) in mammalian genomes that regulate gene expression in different biological processes. Although lncRNAs have been identified in a variety of immune cells and implicated in immune response, the biological function and mechanism of the majority remain unexplored, especially in sepsis. Here, we identify a role for a lncRNA—gastric adenocarcinoma predictive long intergenic noncoding RNA (GAPLINC)—previously characterized for its role in cancer, now in the context of innate immunity, macrophages, and LPS-induced endotoxic shock. Transcriptome analysis of macrophages from humans and mice reveals that GAPLINC is a conserved lncRNA that is highly expressed following macrophage differentiation. Upon inflammatory activation, GAPLINC is rapidly down-regulated. Macrophages depleted of GAPLINC display enhanced expression of inflammatory genes at baseline, while overexpression of GAPLINC suppresses this response. Consistent with GAPLINC-depleted cells, Gaplinc knockout mice display enhanced basal levels of inflammatory genes and show resistance to LPS-induced endotoxic shock. Mechanistically, survival is linked to increased levels of nuclear NF-κB in Gaplinc knockout mice that drives basal expression of target genes typically only activated following inflammatory stimulation. We show that this activation of immune response genes prior to LPS challenge leads to decreased blood clot formation, which protects Gaplinc knockout mice from multiorgan failure and death. Together, our results identify a previously unknown function for GAPLINC as a negative regulator of inflammation and uncover a key role for this lncRNA in modulating endotoxic shock.

scholarly journals Immune response of bovine milk somatic cells to endotoxin in healthy quarters with normal and very low cell counts

2010 ◽  
Vol 77 (4) ◽  
pp. 452-459 ◽  
Author(s):  
Olga Wellnitz ◽  
Amandine Baumert ◽  
Machabbat Saudenowa ◽  
Rupert M Bruckmaier
Keyword(s):  
Immune Response ◽  
Mrna Expression ◽  
Bovine Milk ◽  
Immune Competence ◽  
Immune Functions ◽  
Lps Challenge ◽  
Cell Counts ◽  
Ldh Activity ◽  
Tnf Α ◽  
Immune Factors

Low somatic cell count (SCC) is a reliable indicator of high-quality milk free of pathogenic microorganisms. Thus, an important goal in dairy practice is to produce milk with low SCC. Selection for cows with low SCC can sometimes lead to extremely low SCC in single quarters. The cells in milk are, however, predominantly immune cells with important immune functions. To investigate the mammary immune competence of quarters with very low SCC, healthy udder quarters of cows with normal SCC of (40–100)×103cells/ml and very low SCC of <20×103cells/ml were challenged with lipopolysaccharide (LPS) fromEscherichia coli. In the first experiment, SCC and cell viability after a challenge with 50 ng of LPS/quarter was investigated. In the second experiment, tumour necrosis factor α (TNF-α) concentration and lactate dehydrogenase (LDH) activity in milk, and mRNA expression of various innate immune factors in milk cells were measured after a challenge with 100 μg LPS/quarter. LPS challenge induced an increase of SCC. SCC levels reached were higher in quarters with normal SCC and maximum SCC was reached 1 h earlier than in very low SCC quarters. The increase of TNF-α concentrations in milk in response to LPS challenge was lower in quarters with very low SCC than in quarters with normal SCC. The viability of cells and the LDH activity in milk increased in response to LPS challenge, however, without a difference between the groups. The mRNA expression of IL-1β and IL-8 was increased in milk cells at 12 h after LPS challenge, whereas that of TNF-α and lactoferrin was not increased at the measured time points (12, 24 and 36 h after LPS challenge). No differences of mRNA expression of measured immune factors between normal and very low SCC samples were detected. The study showed that udder quarters with very low SCC responded with a less marked increase of SCC compared with quarters with normal SCC. This difference corresponded with simultaneously lower TNF-α concentrations in milk. However, the immune competence of the cells themselves based on mRNA expression of TNF-α, IL-8, IL-1β, and lactoferrin, did not differ. The results may indicate that very low SCC can impair the immune competence of udder quarters, because the immune response in udder quarters with lower SCC is less efficient as fewer cells contribute to the production of immunoregulators.

scholarly journals MK2 mediates macrophage activation and acute lung injury by regulating let-7e miRNA

2018 ◽  
Vol 315 (3) ◽  
pp. L371-L381 ◽  
Author(s):  
Yaxian Wu ◽  
Huiqiong He ◽  
Yunhe Ding ◽  
Sirui Liu ◽  
Depeng Zhang ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Macrophage Activation ◽  
Critical Role ◽  
Protein A ◽  
Cytokine Expression ◽  
Conditional Knockout ◽  
Lps Challenge ◽  
Tnf Α

MAPK-activated protein kinase 2 (MK2) plays a critical role in the development of inflammation. However, the modulatory mechanisms in macrophage activation and acute lung injury (ALI) have not been completely defined. Here, we reported that MK2-deficient mice (MK2−/−) protected against sepsis-induced ALI. In response to lipopolysaccharide (LPS) challenge, MK2−/− mice and myeloid cell-specific MK2 conditional knockout mice (MK2Lyz2-KO) exhibited attenuated inflammatory response, especially producing fewer amounts of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and macrophage inflammatory protein 2 (MIP-2). LPS treatment in vitro resulted in reduced cytokine expression in MK2−/− bone marrow-derived macrophages (BMDMs). Furthermore, we found that LPS-induced microRNA lethal-7e ( let-7e) expression was significantly increased in MK2−/− macrophages. Transfection of let-7e antagomirs into MK2−/− BMDM rescued LPS-induced expression of TNF-α, IL-6, and MIP-2. In contrast, transfection of let-7e mimics into MK2+/+BMDM decreased cytokine expression. Meanwhile, LPS-induced phosphorylation of cAMP response element-binding (CREB) protein, a substrate of MK2, was downregulated in MK2−/− BMDMs. Lin28, an inhibitory molecule of let-7, was significantly reduced in MK2−/− macrophages. Our results suggested that MK2 boosts LPS-induced macrophage activation and ALI via increasing activation of CREB and consequently, the expression of Lin28 and downregulation of let-7e.

scholarly journals MAP kinase phosphatase 1 controls innate immune responses and suppresses endotoxic shock

2005 ◽  
Vol 203 (1) ◽  
pp. 131-140 ◽  
Author(s):  
Qun Zhao ◽  
Xianxi Wang ◽  
Leif D. Nelin ◽  
Yongxue Yao ◽  
Ranyia Matta ◽  
...  
Keyword(s):  
Map Kinase ◽  
Endotoxic Shock ◽  
Innate Immune ◽  
Innate Immune Responses ◽  
Wild Type ◽  
Kinase Activation ◽  
Lps Challenge ◽  
Map Kinase Phosphatase ◽  
Tnf Α ◽  
Severe Hypotension

Septic shock is a leading cause of morbidity and mortality. However, genetic factors predisposing to septic shock are not fully understood. Excessive production of proinflammatory cytokines, particularly tumor necrosis factor (TNF)-α, and the resultant severe hypotension play a central role in the pathophysiological process. Mitogen-activated protein (MAP) kinase cascades are crucial in the biosynthesis of proinflammatory cytokines. MAP kinase phosphatase (MKP)-1 is an archetypal member of the dual specificity protein phosphatase family that dephosphorylates MAP kinase. Thus, we hypothesize that knockout of the Mkp-1 gene results in prolonged MAP kinase activation, augmented cytokine production, and increased susceptibility to endotoxic shock. Here, we show that knockout of Mkp-1 substantially sensitizes mice to endotoxic shock induced by lipopolysaccharide (LPS) challenge. We demonstrate that upon LPS challenge, Mkp-1−/− cells exhibit prolonged p38 and c-Jun NH2-terminal kinase activation as well as enhanced TNF-α and interleukin (IL)-6 production compared with wild-type cells. After LPS challenge, Mkp-1 knockout mice produce dramatically more TNF-α, IL-6, and IL-10 than do wild-type mice. Consequently, Mkp-1 knockout mice develop severe hypotension and multiple organ failure, and exhibit a remarkable increase in mortality. Our studies demonstrate that MKP-1 is a pivotal feedback control regulator of the innate immune responses and plays a critical role in suppressing endotoxin shock.

Ankyrin-G heterozygous conditional knockout mice display increased sensitivity to social defeat stress

2021 ◽  
Author(s):  
Zachary A. Cordner ◽  
Seva G. Khambadkone ◽  
Shanshan Zhu ◽  
Justin Bai ◽  
Rasadokht Forati ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Social Defeat ◽  
Conditional Knockout ◽  
Social Defeat Stress ◽  
Conditional Knockout Mice ◽  
Ankyrin G ◽  
Increased Sensitivity

scholarly journals 233 NaturSafe® supplementation mitigates some aspects of the acute phase immune response to a lipopolysaccharide (LPS) challenge in weaned beef calves

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 117-117
Author(s):  
Nicole C Burdick Sanchez ◽  
Jeffery A Carroll ◽  
Paul R Broadway ◽  
Tom S Edrington ◽  
Ilkyu Yoon ◽  
...  
Keyword(s):  
Acute Phase ◽  
Treatment Time ◽  
Sickness Behavior ◽  
Serum Cortisol ◽  
Post Challenge ◽  
Serum Samples ◽  
Lps Challenge ◽  
Time Interaction ◽  
Tnf Α ◽  
Monitoring Devices

Abstract This study was conducted to determine if feeding calves NaturSafe would reduce the acute phase response (APR) to lipopolysaccharide (LPS) challenge. Crossbred steers (n=32; 274±2 kg) were randomly allotted to two treatment diets: 1) Control, fed a standard receiving ration, and 2) NaturSafe, fed the Control ration supplemented with NaturSafe at 12 g/hd/d (NaturSafe®, Diamond V). On d22, steers were fitted with indwelling jugular catheters and rectal temperature monitoring devices and placed in individual stalls. On d23, steers were challenged i.v. with 0.25 µg/kg BW LPS. Serum samples were collected and sickness behavior scores (SBS) recorded at 0.5-h intervals from -2 to 8h and at 24h relative to LPS challenge. Rectal temperatures were greater (P=0.01) in NaturSafe compared to Control steers for the following time intervals following LPS challenge: 6 to 11h, 13h, 15 to 20h, and 22 to 24h. Additionally, SBS were reduced (P&lt; 0.01) in NaturSafe compared to Control steers. White blood cell concentrations were greater (P=0.05) in NaturSafe compared to Control steers prior to the LPS challenge, yet the response to LPS did not differ between treatments (P &gt;0.05). A treatment × time interaction for serum cortisol concentrations (P&lt; 0.01) showed an increase at 0.5 and 2h post-challenge but a reduction at 3h in NaturSafe compared to Control steers. Additionally, fibrinogen was greater (P&lt; 0.01) in NaturSafe compared to Control steers. There was a treatment × time interaction (P&lt; 0.01) for TNF-α where concentrations were reduced from 1 to 2h post-challenge in NaturSafe compared to Control steers. Serum IL-6 tended (P=0.09) to show a reduction in serum concentrations in NaturSafe compared to Control steers. There was a tendency (P=0.07) for a treatment × time interaction for IFN-γ. Overall these data suggest a priming effect of NaturSafe on the innate immune system of steers, resulting in an attenuated APR to the LPS challenge.

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