Lipopolysaccharide Administration Research Articles

Single-cell transcriptome analysis of the mouse lungs during the injury and recovery periods after lipopolysaccharide administration.

This study sought to investigate the cellular and molecular alterations during the injury and recovery periods of ALI and develop effective treatments for ALI. Pulmonary histology at 1, 3, 6, and 9 days after lipopolysaccharide administration mice were assessed. An unbiased single-cell RNA sequencing was performed in alveoli tissues from injury (day 3) and recovery (day 6) mice after lipopolysaccharide administration. The roles of Fpr2 and Dpp4 in ALI were assessed. The most severe lung injury occurred on day 3, followed by recovery entirely on day 9 after lipopolysaccharide administration. The numbers of Il1a+ neutrophils, monocytes/macrophages, and Cd4+ and Cd8+ T cells significantly increased at day 3 after LPS administration; subsequently, the number of Il1a+ neutrophils greatly decreased, the numbers of monocytes/macrophages and Cd4+ and Cd8+ T cells continuously increased, and the number of resident alveolar macrophages significantly increased at day 6. The interactions between monocytes/macrophages and pneumocytes during the injury period were enhanced by the Cxcl10/Dpp4 pair, and inhibiting Dpp4 improved ALI significantly, while inhibiting Fpr2 did not. Our results offer valuable insights into the cellular and molecular mechanisms underlying its progression and identify Dpp4 as an effective therapeutic target for ALI.

Locomotor and gait changes in the LPS model of neuroinflammation are correlated with inflammatory cytokines in blood and brain.

Lipopolysaccharide (LPS) challenge in mice has been used to identify the mechanisms and therapeutics for neuroinflammation. In this study, we aimed to comprehensively evaluate the behavioral changes including locomotion, exploration, and memory, correlating them with a panel of thirteen inflammatory cytokines in both blood and brain.We found that acute LPS administration (0.83 mg/Kg i.p.) reduced body weight, food intake, and glucose levels compared to the saline-injected mice, concomitant with decreased activity in home cage monitoring. Locomotion was significantly reduced in Open Field, Introduced Object, and Y-Maze tests. Decreased exploratory behavior in the Y-Maze and Introduced Object tests was noticed, by measuring the number of arms explored and object interaction time, respectively. Additionally, in rotarod, LPS administration led to a significant decrease in the distance achieved, while in the MouseWalker, LPS led to a reduction in average velocity.LPS induced a decrease in microglia ramification index in the motor cortex and the striatum, while surprisingly a reduction in microglia number was observed in the motor cortex.The concentrations of thirteen cytokines in the blood were significantly altered, while only CXCL1, CCL22, CCL17, G-CSF, and IL-12p40 were changed in the brain. Correlations between cytokine levels in blood and brain were found, most notably for CCL17 and CCL22. TGFβ was the only one with negative correlations to other cytokines. Correlations between cytokines and behavior changes were also disclosed, especially for CCL17, CCL22, G-CSF, and IL-6 and negatively for TGFβ and IL-10.In summary, our study employing acute LPS challenge in mice has revealed a comprehensive profile of behavioral alterations alongside significant changes in inflammatory cytokine levels, both in peripheral blood and brain tissue. These findings contribute to a deeper understanding of the interplay between inflammation and behavior, with possible implications for identifying prognostics and therapeutic targets for neuroinflammatory conditions.

NF-κB/miR-455-5p/SOCS3 axis aggravates sepsis induced acute kidney injury through promoting renal inflammation.

Sepsis is the leading contributor to acute kidney injury (AKI), responsible for 45% to 70% of AKI occurrences. Despite this, septic AKI is a highly multifactorial and complex condition, and our grasp of its pathogenesis is still not fully developed. Consequently, there remains a significant gap in effective diagnostic and therapeutic strategies for septic AKI. In the in vitro experiments, BUMPT cells were exposed to lipopolysaccharides (LPS). In vivo experiments involved inducing sepsis in mice through administration of LPS injections. Additionally, in certain experiments, either a miR-455-5p mimic or an anti-miR-455-5p LAN was administered to the mice via injections into the tail vein. The mice were then sacrificed 24 hours following LPS administration for subsequent analysis. We observed a significant elevation in miR-455-5p levels within renal tubular cells following LPS-induced septic AKI. Our investigation revealed that NF-κB plays a crucial role in the upregulation of miR-455-5p. Inhibition of NF-κB using TPCA-1 prevented the rise in miR-455-5p levels in BUMPT cells (mouse proximal tubular cells from Boston University) cultured in vitro. ChIP assays confirmed that NF-κB directly interacts with the promoter region of the miR-455-5p gene in response to LPS treatment. Functionally, introducing miR-455-5p mimics intensified cell apoptosis, kidney damage, and the production of inflammatory cytokines, while silencing miR-455-5p had protective effects in septic mice. Notably, administering anti-miR-455-5p enhanced SOCS3 expression, whereas miR-455-5p mimics reduced SOCS3 levels following LPS exposure. Furthermore, our luciferase reporter assays demonstrated that SOCS3 is a direct target of miR-455-5p. This study indicates a NF-κB/miR-455-5p/SOCS3 axis which can exacerbate kidney damage by enhancing renal inflammation. This process highlights potential therapeutic targets for managing septic AKI.

Flexible Behavioral Adjustment to Frustrative Nonreward in Anticipatory Behavior, but Not in Consummatory Behavior, Requires the Dorsal Hippocampus.

The hippocampus (HC) is recognized for its pivotal role in memory-related plasticity and facilitating adaptive behavioral responses to reward shifts. However, the nature of its involvement in the response to reward downshifts remains to be determined. To bridge this knowledge gap, we explored the HC's function through a series of experiments in various tasks involving reward downshifts and using several neural manipulations in rats. In Experiment 1, complete excitotoxic lesions of the HC impaired choice performance in a modified T-maze after reducing the quantity of sugar pellet rewards. In Experiment 2, chemogenetic inhibition of the dorsal HC (dHC) disrupted anticipatory behavior following a food-pellet reward reduction. Experiments 3-5 impaired HC function by using peripheral lipopolysaccharide (LPS) administration. This treatment, which induces peripheral inflammation affecting HC function, significantly increased cytokine levels in the dHC (Experiment 3) and impaired anticipatory choice behavior (Experiment 4). None of these dorsal hippocampal manipulations affected consummatory responses in animals experiencing sucrose downshifts. Accordingly, we found no evidence of increased neural activation in either the dorsal or ventral HC, as measured by c-Fos expression, after a sucrose downshift task involving consummatory suppression (Experiment 6). The results highlight the HC's pivotal role in adaptively modulating anticipatory behavior in response to a variety of situations involving frustrative nonreward, while having no effect on adjustments on consummatory behavior. The data supporting this conclusion were obtained under heterogeneous experimental conditions derived from a multi-laboratory collaboration, ensuring the robustness and high reproducibility of our findings. Spatial orientation, memory update, choice of reward signals of different values, and anticipatory versus consummatory adjustments to reward downshift are discussed as potential mechanisms that could account for the specific effects observed from HC manipulations.

5114 Establishment of Thyroid Storm Mouse Model and Therapeutic Effects of Ghrelin

Abstract Disclosure: C. Kurimoto: None. Y. Furukawa: None. T. Akamizu: None. A. Doi: None. K. Takeshima: None. S. Morita: None. H. Iwakura: None. H. Ariyasu: None. H. Furuta: None. M. Nishi: None. T. Matsuoka: None. Context: Thyroid storm (TS), a life-threatening condition that can damage multiple organs, is caused by a combination of thyrotoxicosis and severe physical stresses. Infection is the most common triggering factor. Hypercytokinemia is a suggested background, but the pathological condition is unclear and there are no appropriate animal models. Further, TS has limited therapeutic options. Objectives: We aimed to confirm the hypercytokinemia in patients with TS, establish a TS model mouse by triiodothyronine and lipopolysaccharide administration, and explore the therapeutic effects of ghrelin on TS. Methods: We evaluated serum IL-6 levels as a representative marker of hypercytokinemia in patients with TS. As a TS model, C57BL/6 mice were titrated with triiodothyronine and lipopolysaccharide to develop a lethal model with approximately 30% survival at 24 hours. We assessed the survival ratio, mouse sepsis scores and blood biomarkers (IL-6, metanephrine, alanine aminotransferase) and evaluated the effects of ghrelin on these parameters. Results: Serum IL-6 was increased in patients with TS compared with those with Graves' disease without TS (55.7 ± 69.0 vs. 3.13 ± 1.41 pg/mL, P < .05, n=4 each). Next, we titrated the doses of T3 and LPS, aiming to achieve a survival rate of approximately 30% at 24 hours after administration. Two out of five mice in the T3 3.0 mg/kg group died, while none of the eight mice in the T3 1.0 mg/kg group died. Therefore, we determined that the appropriate T3 dose for the TS mouse model is 1.0 mg/kg, which is not lethal when administered alone. In the T3 1.0 mg/kg group (n=8), serum FT3 levels were approximately three times higher (15.3 ± 4.5 vs. 4.5 ± 0.7pg/ml) than those in the control group (n=8). Next, different doses of LPS was added to the T3 group. Survival at 24 hours post-dose was 60% in the T3 + LPS 0.2 mg/kg group (n=5) and 33% in the T3 + LPS 0.5 mg/kg group (n=5), while survival was 100% in the LPS 0.5 mg/kg alone group (n=5),. Based on these findings, the dosage for the murine TS model was determined to be “triiodothyronine 1.0 mg/kg and lipopolysaccharide 0.5 mg/kg”. This TS model group had increased mouse sepsis score, serum IL-6, metanephrine and alanine aminotransferase. In this model, the ghrelin at 300 µg/kg improved the survival rate to 66.7% (P < .01, vs. 0% [saline-treated group]) as well as the mouse sepsis score, and it decreased the serum IL-6 and metanephrine. Conclusion: We confirmed the hypercytokinemia in patients with TS. Next, we established a lethal model simulating TS by inducing “thyrotoxicosis” by exogenous administration of thyroid hormones, and by inducing “sepsis” by intraperitoneal administration of LPS. The model mice exhibited similar pathophysiological status to human TS associated with induction of serum IL-6 and other biomarkers, which were improved by ghrelin. Presentation: 6/1/2024

25-hydroxycholesterol promotes brain cytokine production and leukocyte infiltration in a mouse model of lipopolysaccharide-induced neuroinflammation

Neuroinflammation has been implicated in the pathogenesis of several neurologic and psychiatric disorders. Microglia are key drivers of neuroinflammation and, in response to different inflammatory stimuli, overexpress a proinflammatory signature of genes. Among these, Ch25h is a gene overexpressed in brain tissue from Alzheimer’s disease as well as various mouse models of neuroinflammation. Ch25h encodes cholesterol 25-hydroxylase, an enzyme upregulated in activated microglia under conditions of neuroinflammation, that hydroxylates cholesterol to form 25-hydroxycholesterol (25HC). 25HC can be further metabolized to 7α,25-dihydroxycholesterol, which is a potent chemoattractant of leukocytes. We have previously shown that 25HC increases the production and secretion of the proinflammatory cytokine, IL-1β, by primary mouse microglia treated with lipopolysaccharide (LPS). In the present study, wildtype (WT) and Ch25h-knockout (KO) mice were peripherally administered LPS to induce an inflammatory state in the brain. In LPS-treated WT mice, Ch25h expression and 25HC levels increased in the brain relative to vehicle-treated WT mice. Among LPS-treated WT mice, females produced significantly higher levels of 25HC and showed transcriptomic changes reflecting higher levels of cytokine production and leukocyte migration than WT male mice. However, females were similar to males among LPS-treated KO mice. Ch25h-deficiency coincided with decreased microglial activation in response to systemic LPS. Proinflammatory cytokine production and intra-parenchymal infiltration of leukocytes were significantly lower in KO compared to WT mice. Amounts of IL-1β and IL-6 in the brain strongly correlated with 25HC levels. Our results suggest a proinflammatory role for 25HC in the brain following peripheral administration of LPS.

KLF15 ATTENUATES LIPOPOLYSACCHARIDE-INDUCED APOPTOSIS AND INFLAMMATORY RESPONSE IN RENAL TUBULAR EPITHELIAL CELLS VIA PPARΔ.

Background: The kidney is the most commonly affected organ in sepsis patients, and Krüppel-like transcription factor 15 (KLF15) has a kidney-protective effect and is highly enriched in the kidneys. This study aims to explore the role of KLF15 in sepsis-related acute kidney injury. Methods: A septic injury model in HK2 cells was established through the administration of lipopolysaccharide (LPS), followed by the transfection of an overexpression plasmid for KLF15. Cell viability was assessed using Cell Counting Kit-8 assay, and apoptosis was measured via flow cytometry. The levels of inflammatory cytokines were detected using ELISA, and western blot assay was employed to assess the expression of KLF15, PPARδ, as well as inflammatory and apoptosis-related proteins. The interaction between KLF15 and PPARδ was confirmed through the utilization of online databases and immunoprecipitation experiments. The mechanism was further validated using PPARδ agonists and small interfering RNA. Results: LPS-induced HK2 cells showed downregulated expression of KLF15 and PPARδ, along with decreased viability, accompanied by increased levels of apoptosis, TNFα, IL-1β, and IL-6. Additionally, LPS upregulated the expression of Bax, cytoplasmic cytochrome C [Cytc (cyt)], Cox-2, and p-NF-κB-p65 in HK2 cells, while simultaneously downregulating the expression of Bcl2 and mitochondrial cytochrome c [Cytc (mit)]. immunoprecipitation experiment revealed a possible interaction between KLF15 and PPARδ in HK2 cells. Ov-KLF15, Ov-PPARδ, or administration of PPARδ agonists effectively alleviated the aforementioned alterations induced by LPS. However, interference with PPARδ significantly attenuated the protective effect of Ov-KLF15 on HK2 cells. Conclusion: KLF15 attenuates LPS-induced apoptosis and inflammatory responses in HK2 cells via PPARδ.

Citrullination, a novel posttranslational modification of elastin, is involved in COPD pathogenesis.

Elastin is an extracellular matrix protein (ECM) that supports elasticity of the lung, and in patients with chronic obstructive pulmonary disease (COPD) and emphysema, the structural changes that reduce the amount of elastic recoil, lead to loss of pulmonary function. We recently demonstrated that elastin is a target of peptidyl arginine deiminase (PAD) enzyme-induced citrullination, thereby leading to enhanced susceptibility of this ECM protein to proteolysis. This study aimed to investigate the impact of PAD activity in vivo and furthermore assessed whether pharmacological inhibition of PAD activity protects against pulmonary emphysema. Using a Serpina1a-e knockout mouse model, previously shown to develop inflammation-mediated emphysema, we validated the involvement of PADs in airway disease. In line with emphysema development, intratracheal administration of lipopolysaccharide in combination with PADs provoked significant airspace enlargement (P < 0.001) and diminished lung function, including loss of lung tissue elastance (P = 0.0217) and increases in lung volumes (P = 0.0463). Intraperitoneal treatment of mice with the PAD inhibitor, BB-Cl-amidine, prevented PAD/LPS-mediated lung function decline and emphysema and reduced levels of citrullinated airway elastin (P = 0.0199). These results provide evidence for the impact of PADs on lung function decline, indicating promising potential for the future development of PAD-based therapeutics for preserving lung function in patients with COPD.NEW & NOTEWORTHY This study provides evidence for the impact of peptidyl arginine deiminase (PAD) enzymes on lung function decline, indicating promising potential for the future development of PAD-based therapeutics for preserving lung function in patients with COPD.

The Alpha-7 Nicotinic Receptor Positive Allosteric Modulator PNU120596 Attenuates Lipopolysaccharide-Induced Depressive-Like Behaviors and Cognitive Impairment by Regulating the PPAR-α Signaling Pathway in Mice.

The brain α7 nicotinic acetylcholine receptor (α7 nAChR) has a critical role in the pathophysiology of Major Depressive Disorder (MDD) involving neuroinflammation. The α7 nAChR stimulation has been shown to modulate the anti-inflammatory effects of nuclear peroxisome proliferator-activated receptor-α (PPAR-α) via its endogenous ligands in the brain. The present study determined the effects of α7 nAChR modulator PNU120596 on PPAR-α, an inhibitor of κB (IκB) and nuclear factor-κB (NF-κB) expression and interleukin-1β (IL-1β) level in the hippocampus and prefrontal cortex (PFC) in an inflammatory mouse model of MDD induced by lipopolysaccharide (LPS). We also evaluated the combined effects of PNU120596 and GW6471, a PPAR-α antagonist, on depressive-like and cognitive deficit-like behaviors in mice. Male C57BL/6J mice were treated with PNU120596, followed by systemic LPS (1 mg/kg, i.p.) administration. The effects of PNU120596 on the mRNA expression of PPAR-α and IκB were assessed in the hippocampus and PFC using qRT-PCR following LPS administration. Similarly, the effects of PNU120596 on the immunoreactivity of PPAR-α and NF-κB were measured in the hippocampus and PFC using an immunofluorescence assay. Furthermore, the effects of PNU120596 on pro-inflammatory cytokine IL-1β levels were measured in the hippocampus and PFC using ELISA. The combined effects of PNU120596 and GW6471 were also assessed against LPS-induced depressive-like and cognitive deficit-like behaviors using the Tail Suspension Test (TST), Forced Swim Test (FST), and Y-maze test. PNU120596 (4 mg/kg) significantly prevented LPS-induced dysregulation of PPAR-α, IκB, p-NF-κB p65, and IL-1β in the hippocampus and PFC. Pretreatment with PNU120596 showed significant antidepressant-like effects by reducing immobility time in the TST and FST. Similarly, pretreatment with PNU120596 significantly reduced cognitive deficit-like behavior in the Y-maze test. The antidepressant and pro-cognitive-like effects of PNU120596 were reversed by PPAR-α antagonist GW6471 (2 mg/kg). These results suggest that PNU120596 prevented LPS-induced MDD and cognitivelike behavior by regulating α7 nAChR/PPAR-α signaling pathway in the hippocampus and PFC.

A mouse model of overexpression of human IL-6 by tissue-resident macrophages in the context of LPS-induced inflammation

Chronic inflammation caused by overexpression of IL-6 underlies a number of pathological conditions Mouse models of systemic chronic inflammation with overexpression of human IL-6 (hIL-6) are in demand not only in the context of studying the molecular mechanisms of inflammation, but also in assessing the effectiveness of clinically approved or newly developed IL-6 inhibitors. One experimental approach in addressing such models in mice relies on the induction of systemic acute inflammation in response to lipopolysaccharide (LPS) administration. This work describes mice with tamoxifen-dependent overexpression of human IL-6 in CX3CR1+ myeloid cells in the context of systemic inflammation induced by LPS administration. Our study demonstrates that the highest expression of the transgene carrying IL6 was observed in the heart, while high production of this cytokine was detected in the blood serum. In response to LPS administration, the production of hIL-6 in the blood increased in transgenic mice, while the production of mIL-6 also increased and was comparable to that in wild-type mice. The consequences of high systemic production of hIL-6, which in our model originates from CX3CR1+ tissue-resident macrophages, were noticeable even in the organs in which these cells are not present. Thus, significant amounts of hIL-6 were detected in tissue lysates of the lungs of transgenic mice after LPS administration. Evaluation of the expression of genes encoding cytokines and markers of tissue remodeling upon injury using quantitative real-time PCR showed significant changes in their expression in the context of LPS-induced systemic inflammation. Thus, this work demonstrates the feasibility of using a mouse model with tamoxifen-dependent transgene activation in CX3CR1+ tissue-resident macrophages to study the effects of systemic overexpression of IL-6 and pharmacological blockade of this cytokine with clinically approved or newly developed inhibitors in the context of experimentally induced diseases.

Lipopolysaccharide accelerates peristalsis by stimulating glucagon-like peptide-1 release from L cells in the rat proximal colon.

Upon epithelial barrier dysfunction, lipopolysaccharide (LPS) stimulates glucagon-like peptide-1 (GLP-1) secretion from enteroendocrine L cells by activating Toll-like receptor 4 (TLR4). Because GLP-1 accelerates peristalsis in the proximal colon, the present study aimed to explore whether LPS facilitates colonic peristalsis by stimulating L cell-derived GLP-1 release. In isolated segments of rat proximal colon that were serosally perfused with physiological salt solution and luminally perfused with 0.9% saline, peristaltic wall motion was video recorded and converted into spatio-temporal maps. Fluorescence immunohistochemistry was also carried out. Intraluminal administration of LPS (100 or 1µgmL-1 but not 100ngmL-1) increased the frequency of oro-aboral propagating peristaltic contractions. The LPS-induced acceleration of colonic peristalsis was blocked by TAK-242 (the TLR4 antagonist), exendin-3 (the GLP-1 receptor antagonist) or BIBN4096 (the calcitonin gene-related peptide receptor antagonist). GLP-1-positive epithelial cells co-expressed TLR4 immunoreactivity. In aspirin-pretreated preparations where epithelial barrier function had been impaired, a lower dose of LPS (100ngmL-1) became capable of accelerating peristalsis. By contrast, luminally applied dimethyl sulphoxide, a reactive oxygen species scavenger that protects epithelial integrity, attenuated the prokinetic effects of a higher dose of LPS (100µgmL-1). In colonic segments of a stress rat model leading to a leaky gut, LPS induced more pronounced prokinetic effects. Colonic L cells may well sense luminal LPS via TLR4 triggering the release of GLP-1 that stimulates calcitonin gene-related peptide-containing neurons. The resultant acceleration of peristalsis would facilitate excretion of Gram-negative bacteria from the intestine, and thus L cells may have a protective role against intestinal bacterial infections. KEY POINTS: Colonic epithelial cells form a barrier against bacterial invasion but also may contribute more actively to the exclusion of luminal pathogen by stimulating colonic motility. Luminal lipopolysaccharide (LPS) accelerated colonic peristalsis by stimulating calcitonin gene-related peptide-containing neurons. The prokinetic effect of LPS was mediated by the secretion of glucagon-like peptide-1 from enteroendocrine L cells in which Toll-like receptor 4 was expressed. The LPS-mediated acceleration of peristalsis depended on epithelial barrier integrity. L cells have a defensive role against Gram-negative bacterial infections by facilitating faecal excretion, and could be a potential therapeutic target for gastrointestinal infections.

Targeting the PI3K/AKT signaling pathway with PNU120596 protects against LPS-induced acute lung injury.

This study investigated the potential therapeutic benefits of PNU120596, a positive allosteric modulator of the α7 nicotinic acetylcholine receptor (α7nAChR), in mitigating acute lung injury (ALI) induced by lipopolysaccharide (LPS) in a mouse model. Specifically, we sought to examine the impact of PNU120596 on the PI3K/AKT signaling pathway in the context of ALI. ALI was induced in mice by LPS administration, and the protective effects of PNU120596 were assessed. Lung injury, lung function, and the inflammatory response were evaluated. Additionally, the activation of the PI3K/AKT signaling pathway was examined, along with the levels of inflammatory factors and oxidative stress markers. PNU120596 significantly ameliorated LPS-induced lung injury, improved lung function, and reduced the inflammatory response in the mouse model of ALI. Furthermore, we observed that PNU120596 inhibited the activation of the PI3K/AKT signaling pathway, which was associated with decreased levels of inflammatory factors and oxidative stress markers. PNU120596 exhibits promising therapeutic potential for the treatment of acute lung injury, potentially by targeting the PI3K/AKT signaling pathway. These findings suggest that modulation of the α7 nicotinic acetylcholine receptor with PNU120596 may offer a viable strategy for the management of ALI, warranting further investigation and potential clinical applications.

Sex-Specific Behavioral and Molecular Responses to Maternal Lipopolysaccharide-Induced Immune Activation in a Murine Model: Implications for Neurodevelopmental Disorders.

Maternal immune activation (MIA) during pregnancy has been increasingly recognized as a critical factor in the development of neurodevelopmental disorders, with potential sex-specific impacts that are not yet fully understood. In this study, we utilized a murine model to explore the behavioral and molecular consequences of MIA induced by lipopolysaccharide (LPS) administration on embryonic day 12.5. Our findings indicate that male offspring exposed to LPS exhibited significant increases in anxiety-like and depression-like behaviors, while female offspring did not show comparable changes. Molecular analyses revealed alterations in pro-inflammatory cytokine levels and synaptic gene expression in male offspring, suggesting that these molecular disruptions may underlie the observed behavioral differences. These results emphasize the importance of considering sex as a biological variable in studies of neurodevelopmental disorders and highlight the need for further molecular investigations to understand the mechanisms driving these sex-specific outcomes. Our study contributes to the growing evidence that prenatal immune challenges play a pivotal role in the etiology of neurodevelopmental disorders and underscores the potential for sex-specific preventative approaches of MIA.

The anti-inflammatory effects of Fuzapladib in an endotoxemic porcine model.

Endotoxemia is a systemic inflammatory condition caused by lipopolysaccharide (LPS) stimulation, which produces inflammatory cytokines. Fuzapladib (FZP) inhibits the activation of adhesion molecules found on the surface of inflammatory cells, mitigating inflammation. In this study, we evaluated the therapeutic effects of fuzapladib on inflammatory cytokines and cardio-respiratory function using an LPS-induced endotoxemic porcine model. Fifteen pigs were separated into three groups: low-FZP (n=5), high-FZP (n=5), and control (n=5). Pigs were administered LPS under general anesthesia, and complete blood cell count, blood biochemistry, inflammatory cytokines, and cardio-respiratory function were evaluated. Statistical analysis was performed using a linear mixed-effects model and the Steel-Dwass test, with a significance threshold of P<0.05. During the 4 hr experimental period, one pig in the control group and two pigs in the low-FZP group died due to hypoxemia and hypotension. In the early acute changes following LPS administration, the high-FZP group maintained significantly higher arterial oxygen partial pressure and normal blood pressure compared to the control group. Although interleukin-6 levels increased in all groups during the experiment, they were significantly lower in the high-FZP group compared to the control group. Other parameters showed no clinically significant differences. In conclusion, while high-dose fuzapladib did not reduce organ damage in the porcine endotoxemia model, it suppressed interleukin-6 production, delayed the progression of deterioration, and contributed to a reduction in mortality during the observation period.

An adenosinergic positive feedback loop extends pharmacological cardioprotection duration.

Adenosine receptor activation induces delayed, sustained cardioprotection against ischaemia-reperfusion (IR) injury (24-72 h), but the mechanisms underlying extendedcardioprotection duration remain unresolved. We hypothesized that a positive feedback loop involving adenosine receptor-induced proteasomal degradation of adenosine kinase (ADK) and decreased myocardial adenosine metabolism extends the duration of cardioprotection. Mice were administered an ADK inhibitor, ABT-702, to induce endogenous adenosine signalling. Cardiac ADK protein and mRNA levels were analysed 24-120 h later. Theophylline or bortezomib was administered 24 h after ABT-702 to examine the late roles of adenosine receptors or proteasomal activity, respectively, in ADK expression and cardioprotection at 72 h. Coronary flow and IR tolerance were analysed by Langendorff technique. The potential for continuous adenosinergic cardioprotection was examined using heterozygous, cardiac-specific ADK KO (cADK+/-) mice. Cardiac ADK expression was also examined after A1 or A3 receptor agonist, phenylephrine, lipopolysaccharide or sildenafil administration. ABT-702 treatment decreased ADK protein content and provided cardioprotection from 24 to 72 h. ADK mRNA upregulation restored ADK protein after 96-120 h. Adenosine receptor or proteasome inhibition at 24 h reversed ABT-702-induced ADK protein deficit and cardioprotection at 72 h. cADK+/- hearts exhibited continuous cardioprotection. Diverse preconditioning agents also diminished cardiac ADK protein expression. A positive feedback loop driven by adenosine receptor-induced ADK degradation and renewed adenosine signalling extends the duration of cardioprotection by ABT-702 and possibly other preconditioning agents. The therapeutic potential of continuous adenosinergic cardioprotection is demonstrated in cADK+/- hearts.

Suppressive Effects of β-Hydroxybutyrate Administration on Lipopolysaccharide-Induced Inflammation in Broiler Chickens.

This study aimed to evaluate the suppressive effects of β-hydroxybutyrate (BHB) administration on lipopolysaccharide (LPS)-induced inflammation in broiler chickens. Twenty-day-old male broiler chickens were randomly allocated to three groups, each of which was treated with saline (control), intraperitoneal administration of LPS [1.5 mg/kg body weight (BW), Escherichia coli O127:B8], or LPS plus BHB (3 mmol/kg BW). Plasma albumin and total protein concentration were significantly reduced by LPS administration, while BHB co-treatment partially attenuated the effects. The LPS treatment significantly induced plasma aspartate and alanine aminotransferase activities, and interleukin (IL)-6 concentration, with the increases suppressed by BHB co-treatment (p < 0.05). The LPS treatment significantly increased the gene expression levels of IL-1β, IL-6, and IL-18 in the spleen and peripheral blood monocytes (PBMC), while the increases were partially attenuated by BHB in the spleen. Relatively higher levels of BHB dehydrogenase 1 and succinyl-CoA:3-ketoacid CoA transferase were observed in the spleen and skeletal muscle, while these gene levels were lower in PBMC and the liver. The present results suggest that BHB can suppress LPS-induced inflammation, in which ketolytic enzyme expression levels may be involved in broiler chickens.

Molecular hydrogen supplementation in mice ameliorates lipopolysaccharide-induced loss of interest.

The objective of this study was to evaluate the potential of hydrogen in preventing and treating psychiatric symptoms, particularly depressed mood and loss of interest, and to explore its underlying mechanisms. A mouse model exhibiting inflammation-derived depressive symptoms was used for the investigation. Institute of Cancer Research mice were subjected to a 7-day intervention of either 30% hydrogen or 40 g per day of air via jelly intake. On the final day, lipopolysaccharide (LPS) was intraperitoneally administered at 5 mg/kg to induce inflammation-related depressive symptoms. Behavioral and biochemical assessments were conducted 24 h post-LPS administration. Following LPS administration, a decrease in spontaneous behavior was observed; however, this effect was mitigated in the group treated with hydrogen. The social interaction test revealed a significant reduction in interactions with unfamiliar mice in the LPS-treated group, whereas the hydrogen-treated group exhibited no such decrease. No significant changes were noted in the forced-swim test for either group. Additionally, the administration of LPS in the hydrogen group did not result in a decrease in zonula occludens-1, a biochemical marker associated with barrier function at the cerebrovascular barrier and expressed in tight junctions. Hydrogen administration demonstrated a preventive effect against the LPS-induced loss of interest, suggesting a potential role in symptom prevention. However, it did not exhibit a suppressive effect on depressive symptoms in this particular model. These findings highlight the nuanced impact of hydrogen in the context of inflammation-induced psychiatric symptoms, indicating potential avenues for further exploration and research.

Indole-3-propionic acid enhances growth performance and reduces diarrhea via modulating redox status and intestinal inflammation in weaned piglets

Indole-3-propionic acid (IPA) has anti-inflammatory properties, which can be beneficial for weaned piglets with underdeveloped immune systems. The study explores the impact of IPA supplementation on growth performance, oxidative stress, and inflammation response in weaned piglets. In experiment (Exp.) 1, ninety weaned piglets were divided into six groups (five replicates per group, three pigs per replicate), with each group receiving a basal diet with varying amounts of IPA (0, 50, 100, 200, 400, or 600 mg/kg) for 42 d. Piglets fed the diets with 50, 100, and 200 mg/kg of IPA exhibited reduced feed conversion ratios (F: G) compared to the control piglets (P = 0.035). Notably, 50 and 100 mg/kg IPA treatments significantly reduced diarrhea incidence and serum interleukin (IL)-6 content (P < 0.05). Conversely, a high dosage of 600 mg/kg IPA led to increased serum contents of tumor necrosis factor (TNF)-α, and IL-6 (P < 0.05). Optimal antioxidant benefits were observed at 100 mg/kg IPA supplementation, which significantly reduced malondialdehyde levels while enhancing serum total antioxidant capacity and total superoxide dismutase activity on d 14 (P < 0.05). Exp. 2 investigated the effects of IPA on lipopolysaccharide (LPS) challenge in weaned piglets. The study consisted of 32 weaned piglets allocated into 4 groups, with 8 replicates per group and 1 piglet per replicate: a control group, a LPS challenge group, a LPS challenge group supplemented with 100 mg/kg IPA, and a group supplemented with 100 mg/kg IPA alone. Upon administration of LPS or saline injection, the results indicated that dietary IPA supplementation in challenged piglets enhanced villus height: crypt depth, modulated IL-8 and IL-22 mRNA relative expression, and increased the tight junction protein claudin-1 mRNA relative expression in the intestinal mucosa (P < 0.05). These findings suggest that dietary supplementation of IPA at specific concentrations significantly improves growth performance, reduces diarrhea incidence, and mitigates inflammation and oxidative stress in weaned piglets. It may be concluded that incorporating IPA into the diet of weaned piglets can effectively improve their health and development.

Antidepressant effect of PT-31, an α₂-adrenoceptor agonist, on lipopolysaccharide-induced depressive-like behavior in mice.

Increasing evidence indicates that neuroinflammation, oxidative stress, and neurotrophic factors play a key role in the pathophysiology of major depressive disorder (MDD). In addition, the attenuation of inflammatory response has been considered a putative mechanism for MDD treatment. PT-31 is an imidazolidine derivative and a putative α₂-adrenoceptor agonist that has previously demonstrated antinociceptive activity. The present study aimed to investigate the effect of PT-31 on depressive-like behavior and lipopolysaccharide-induced neurochemical changes. To this end, mice received intraperitoneally saline or lipopolysaccharide (600 µg/kg), and 5 h postinjection animals were orally treated with saline, PT-31 (3, 10, and 30 mg/kg), or fluoxetine (30 mg/kg). Mice were subjected to the open field test (OFT) 6 and 24 h after lipopolysaccharide administration and to the tail suspension test (TST) 24 h postlipopolysaccharide. Subsequently, animals were euthanized, and brains were dissected for neurochemical analyses. The administration of lipopolysaccharide-induced sickness- and depressive-like behaviors, besides promoting an increase in myeloperoxidase activity and a reduction in brain-derived neurotrophic factor (BDNF) levels. Noteworthy, PT-31 3 mg/kg attenuated lipopolysaccharide-induced decreased locomotor activity 6 h after lipopolysaccharide in the OFT. All tested doses of PT-31 significantly reduced the immobility time of animals in the TST and attenuated lipopolysaccharide-induced increased myeloperoxidase activity in the cortex of mice. Our results demonstrate that PT-31 ameliorates behavioral changes promoted by lipopolysaccharide in OFT and TST, which is possibly mediated by attenuation of the inflammatory response.

Pleiotrophin modulates acute and long-term LPS-induced neuroinflammatory responses and hippocampal neurogenesis

The hippocampus is one of the most vulnerable regions affected in disorders characterized by overt neuroinflammation such as neurodegenerative diseases. Pleiotrophin (PTN) is a neurotrophic factor that modulates acute neuroinflammation in different contexts. PTN is found highly upregulated in the brain in different chronic disorders characterized by neuroinflammation, suggesting an important role in the modulation of sustained neuroinflammation. To test this hypothesis, we studied the acute and long-term effects of a single lipopolysaccharide (LPS; 5mg/kg) administration in Ptn+/+ and Ptn-/- mice, and in mice with Ptn-overexpression (Ptn-Tg). Endogenous PTN levels proportionally modulate LPS-induced increase in TNF-α plasma levels one hour after treatment. In the dentate gyrus (DG) of the hippocampus, a lower percentage of DCX+ cells were detected in saline-treated Ptn-/- mice compared to Ptn+/+ mice, suggesting a crucial role of PTN in the maintenance of hippocampal neuronal progenitors. The data show that PTN overexpression tends to potentiate acute microglial responses in the DG 16hours after LPS treatment. Remarkably, a significant increase in the number of neuronal progenitors together with astrogliosis was detected 10 months after a single injection of LPS treatment in wild type mice. However, these LPS-induced long-term effects were prevented in Ptn-/- and Ptn-Tg mice, suggesting that PTN modulates LPS-induced long-term neurogenesis changes and astrocytic response in the hippocampus. The data presented here suggest that endogenous PTN levels are crucial in the regulation of acute LPS-induced systemic and hippocampal microglial responses in young mice. Furthermore, our findings provide evidence of the key role of PTN in the regulation of long-term LPS effects on astrocytic response and neurogenesis in the hippocampus.