Anti-inflammatory effects of benzenediamine derivate FC-98 on sepsis injury in mice via suppression of JNK, NF-κB and IRF3 signaling pathways

ANKRD22 aggravates sepsis-induced ARDS and promotes pulmonary M1 macrophage polarization

Acute respiratory distress syndrome (ARDS) is independently associated with a poor prognosis in patients with sepsis. Macrophage M1 polarization plays an instrumental role in this process. Therefore, the exploration of key molecules affecting acute lung injury and macrophage M1 polarization may provide therapeutic targets for the treatment of septic ARDS. Here, we identified that elevated levels of Ankyrin repeat domain-containing protein 22 (ANKRD22) were associated with poor prognosis and more pronounced M1 macrophage polarization in septic patients by analyzing high-throughput data. ANKRD22 expression was also significantly upregulated in the alveolar lavage fluid, peripheral blood, and lung tissue of septic ARDS model mice. Knockdown of ANKRD22 significantly attenuated acute lung injury in mice with sepsis-induced ARDS and reduced the M1 polarization of lung macrophages. Furthermore, deletion of ANKRD22 in macrophages inhibited M1 macrophage polarization and reduced levels of phosphorylated IRF3 and intracellular interferon regulatory factor 3 (IRF3) expression, while re-expression of ANKRD22 reversed these changes. Further experiments revealed that ANKRD22 promotes IRF3 activation by binding to mitochondrial antiviral-signaling protein (MAVS). In conclusion, these findings suggest that ANKRD22 promotes the M1 polarization of lung macrophages and exacerbates sepsis-induced ARDS.

Dimethyl itaconic acid improves viability and steroidogenesis and suppresses cytokine production in LPS-treated bovine ovarian granulosa cells by regulating TLR4/nfkβ, NLRP3, JNK signaling pathways

The stimulation of pro-inflammatory pathways by lipopolysaccharide (LPS) endotoxins is a key player in the pathological mechanisms involved in the development of ovarian dysfunctions in dairy cows. Dimethyl itaconate acid (DMIA) is a novel immunometabolite that has recently emerged as a regulator of inflammatory responses in mammals. The present study was undertaken to determine the anti-inflammatory effects of DMIA on bovine granulosa cells (GCs) and to explore its possible molecular mechanisms. The ovarian GCs were obtained from small follicles of dairy cows. The GCs were stimulated with 1 μg/mL LPS for 4 h and then treated with 250 μM DMIA for 12 h. The viability, production of pro-inflammatory cytokines, activation of inflammatory signaling pathways and synthesis of steroid hormones were evaluated in treated GCs. Our results showed that DMIA reduced the inflammatory responses in LPS stimulated GCs by down-regulating the expression of nod-like receptor family pyrin domain containing 3 inflammasome, and toll-like receptor 4 and by suppressing the phosphorylation of nuclear factor kappa B and c-Jun N-terminal kinase proteins. DMIA also attenuated the increased production of pro inflammatory cytokines (interleukin 6, tumor necrosis factor α and interleukin 1 beta (p < 0.01) in LPS stimulated GCs. Exposure of LPS stimulated GCs to DMIA improved the impaired steroidogenesis by up-regulation of steroid synthesis genes including 3-beta-hydroxysteroid dehydrogenase, follicle stimulating hormone receptor and cytochrome P450 aromatase. The results of the present study highlight the potential role of itaconic acid for the improvement of GCs inflammation in dairy cows with ovarian dysfunctions.

Synergistic activity and immunomodulatory potential of levofloxacin and Synoeca-MP peptide against multi-resistant strains of Klebsiella pneumoniae

The purpose of this article is to study the isolated and combined effect of the peptides Synoeca-MP and IDR-1018 against multi-resistant clinical isolates of K. pneumoniae (Kp2177569 - LACEN) in vitro. The bactericidal activity of the peptide Synoeca-MP in combination with three different classes of commercial antimicrobials and its immunomodulatory potential was also evaluated. Synoeca-MP showed better antimicrobial activity than IDR-1018 and presented synergistic action combined with levofloxacin. Therefore, Synoeca-MP and levofloxacin, and the combination of both, were used in subsequent analyses. In the presence of heat-killed antigens, cellular viability and TNF-α levels was maintained, the production of NO increased and a reduction in IL-10 production was observed. The synergistic antibacterial effect between Synoeca-MP and levofloxacin was effective against multidrug-resistant strains of K. pneumoniae. The association of Synoeca-MP and levofloxacin may present a low modulating action of pro and anti-inflammatory mediators, based on these results.

Knockdown of lncRNA TapSAKI alleviates LPS-induced injury in HK-2 cells through the miR-205/IRF3 pathway

Sepsis is a common and lethal syndrome. Long non-coding RNA (lncRNA) transcript predicting survival in AKI (TapSAKI) has recently been found to serve as an important regulator in sepsis. However, the underlying mechanism of TapSAKI in sepsis pathogenesis remains largely unknown. Our data demonstrated that lipopolysaccharide (LPS)-induced HK-2 cell injury by weakening cell viability and enhancing cell apoptosis and inflammation. TapSAKI was upregulated and miR-205 was downregulated in LPS-induced HK-2 cells. TapSAKI knockdown or miR-205 overexpression alleviated LPS-induced cytotoxicity in HK-2 cells. TapSAKI sequestered miR-205 via acting as a miR-205 sponge. Moreover, the mitigating effect of TapSAKI silencing on LPS-induced HK-2 cell injury was mediated by miR-205. Additionally, the interferon regulatory factor 3 (IRF3) signaling was involved in the regulation of the TapSAKI/miR-205 axis on LPS-induced HK-2 cell damage. Our current study suggested that TapSAKI silencing relieved LPS-induced injury in HK-2 cells at least in part by sponging miR-205 and regulating the IRF3 signaling pathway, highlighting a novel understanding for sepsis pathogenesis and a promising target for this disease treatment.

Regulatory role of the TLR4/JNK signaling pathway in sepsis‑induced myocardial dysfunction

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection, and is a leading cause of mortality worldwide. Myocardial dysfunction is associated with poor prognosis in patients with sepsis and contributes to a high risk of mortality. However, the pathophysiological mechanisms underlying sepsis-induced myocardial dysfunction are not completely understood. The aim of the present study was to investigate the role of toll-like receptor 4 (TLR4)/c-Jun N-terminal kinase (JNK) signaling in pro-inflammatory cytokine expression and cardiac dysfunction during lipopolysaccharide (LPS)-induced sepsis in mice. C57BL/6 mice were pretreated with TAK-242 or saline for 1 h and then subjected to LPS (12 mg/kg, intraperitoneal) treatment. Cardiac function was assessed using an echocardiogram. The morphological changes of the myocardium were examined by hematoxylin and eosin staining and transmission electron microscopy. The serum protein levels of cardiac troponin I (cTnI) and tumor necrosis factor-α (TNF-α) were determined by an enzyme-linked immunosorbent assay (ELISA). The TLR4 and JNK mRNA levels were analyzed via reverse transcription-quantitative PCR. TLR4, JNK and phosphorylated-JNK protein levels were measured by western blotting. In response to LPS, the activation of TLR4 and JNK in the myocardium was upregulated. There were significant increases in the serum levels of TNF-α and cTnI, as well as histopathological changes in the myocardium and suppressed cardiac function, following LPS stimulation. Inhibition of TLR4 activation using TAK-242 led to a decrease in the activation of JNK and reduced the protein expression of TNF-α in plasma, and alleviated histological myocardial injury and improved cardiac function during sepsis in mice. The present data suggested that the TLR4/JNK signaling pathway played a critical role in regulating the production of pro-inflammatory cytokines and myocardial dysfunction induced by LPS.

MCP-induced protein 1 attenuates sepsis-induced acute lung injury by modulating macrophage polarization via the JNK/c-Myc pathway

Sepsis is a potentially fatal systemic inflammatory response syndrome caused by infection. In this study, we evaluated the effects of MCP-induced protein 1 (MCPIP1), a recently discovered inflammation-related ribonuclease, on sepsis-induced acute lung injury (ALI) and investigated the underlying mechanisms. Cecal ligation puncture and lipopolysaccharide induction were performed on Sprague-Dawley rats and RAW264.7 cells, respectively, to establish sepsis-induced ALI models. The proteasome inhibitor MG132 used as an activator of MCPIP1 overexpression, and we showed that MG132 can indeed increase the expression of MCPIP1. MCPIP1 overexpression induced by MG132 alleviated sepsis-induced pathologic changes, water content and protein leakage in the lungs, and induction of systemic inflammatory mediators, and improved the 7-day mortality rate in the model rats. We also showed that MCPIP1 p showed romoted macrophage polarization from the M1 to the M2 type in sepsis-induced ALI. Furthermore, MCPIP1-enhanced M2 polarization was inhibited by an MCPIP1-targeting small interfering RNA (siMCPIP1) in RAW264.7 cells. Further mechanistic studies showed that the promotive effect of MCPIP1 on M2 polarization was related to the inhibition of c-Jun N-terminal kinase (JNK) and its downstream transcription factor c-Myc in the in vitro model. Conversely, siMCPIP1 transfection resulted in the recovery of JNK and c-Myc expression in LPS-treated cells. Taken together, these findings indicate that MCPIP1 plays a protective role in sepsis-induced ALI by modulating macrophage polarization through inhibition of the JNK/c-Myc signaling pathway. Our study presents a potentially novel therapeutic strategy for the treatment of lung injury involving the inflammatory cascade.

Cx43 Inhibition Attenuates Sepsis-Induced Intestinal Injury via Downregulating ROS Transfer and the Activation of the JNK1/Sirt1/FoxO3a Signaling Pathway

Intestinal injury has long been considered to play a crucial role in the pathophysiology of sepsis and has even been characterized as the “motor” of it. Thus, we explored the effects of connexin43 (Cx43) on sepsis-induced intestinal injury in order to provide potential therapeutic strategies. Rat cecal ligation and puncture (CLP) models in vivo and cell models (IEC-6 cells) pretreated with LPS in vitro were used in the current study. Firstly, different methods, such as Cx43 inhibitors (18-α-GA and oleamide) or siRNA targeting Cx43 and N-acetyl cysteine (NAC) (a kind of ROS scavenger), were used to observe the effects of Cx43 channels mediating ROS transfer on intestinal injury. Secondly, the influence of ROS content on the activity of the JNK1/Sirt1/FoxO3a signaling pathway was explored through the application of NAC, sp600125 (a JNK1 inhibitor), and nicotinamide (a Sirt1 inhibitor). Finally, luciferase assays and ChIP were used to determine the direct regulation of FoxO3a on proapoptotic proteins, Bim and Puma. The results showed that sepsis-induced intestinal injury presented a dynamic change, coincident with the alternation of Cx43 expression. The inhibition of Cx43 attenuated CLP-induced intestinal injury in vivo and LPS-induced IEC-6 injury in vitro. The changes of Cx43 channel function regulated ROS transfer between the neighboring cells, which mediated the activation of the JNK1/Sirt1/FoxO3a signaling pathway. FoxO3a directly affected its downstream target genes, Bim and Puma, which are responsible for cell or tissue apoptosis. In summary, our results suggest that Cx43 inhibition suppresses ROS transfer and inactivates the JNK1/Sirt1/FoxO3a signaling pathway to protect against sepsis-induced intestinal injury.

Anti-Inflammatory Effects of Aurantio-Obtusin from Seed of Cassia obtusifolia L. through Modulation of the NF-κB Pathway

Aurantio-obtusin, an anthraquinone compound, isolated from dried seeds of Cassia obtusifolia L. (syn. Senna obtusifolia; Fabaceae) and Cassia tora L. (syn. Senna tora). Although the biological activities of Semen Cassiae have been reported, the anti-inflammatory mechanism of aurantio-obtusin, its main compound, on RAW264.7 cells, remained unknown. We investigated the anti-inflammatory effect of aurantio-obtusin on lipopolysaccharide- (LPS)-induced RAW264.7 cells in vitro and elucidated the possible underlying molecular mechanisms. Nitric oxide production (NO) and prostaglandin E₂ (PGE₂) were measured by the Griess colorimetric method and enzyme-linked immunosorbent assay (ELISA), respectively. Protein expression levels of cyclooxygenase 2 (COX-2) were monitored by cell-based ELISA. Interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-α) synthesis were analyzed using ELISA. The mRNA expression of nitric oxide synthase (iNOS), COX-2, and the critical pro-inflammatory cytokines (IL-6 and TNF-α) were detected by quantitative real-time PCR. Aurantio-obtusin significantly decreased the production of NO, PGE₂, and inhibited the protein expression of COX-2, TNF-α and IL-6, which were similar to those gene expression of iNOS, COX-2, TNF-α and IL-6 (p < 0.01). Consistent with the pro-inflammatory gene expression, the Aurantio-obtusin efficiently reduced the LPS-induced activation of nuclear factor-κB in RAW264.7 cells. These results suggested that aurantio-obtusin may function as a therapeutic agent and can be considered in the further development of treatments for a variety of inflammatory diseases. Further studies may provide scientific evidence for the use of aurantio-obstusin as a new therapeutic agent for inflammation-related diseases.

Inflammatory cytokine expression in patients with sepsis at an intensive care unit

Sepsis is a systemic inflammatory response syndrome caused by infection of bacteria, fungi and/or viruses in clinical patients. It is known that inflammatory cytokine levels have an essential role in the progression of sepsis. The present study investigated the role of inflammatory markers in human peripheral blood mononuclear cells (hPBMCs) of patients with sepsis at an intensive care unit. In addition, the plasma levels of inflammatory cytokines were compared between sepsis patients and healthy individuals. The results demonstrated that the serum levels of interleukin-1, -17 and -6, as well as tumor necrosis factor-α, were upregulated in sepsis patients. The serum levels of high mobility group box 1 and C-reactive protein were increased in sepsis patients compared with those in healthy individuals. The expression levels of nuclear factor-κB-p65 and its inhibitor IκBα, as well as the ratio of CD25⁺ cells, and the levels of neutrophil gelatinase-associated lipocalin and peptidoglycan recognition protein were higher in hPBMCs in sepsis patients compared with those in healthy individuals. It was also indicated that balance of T helper type 1/2 cytokines was also disturbed in patients with sepsis compared with that in healthy individuals. In conclusion, these results indicated that inflammation is involved in the progression of sepsis by interfering with the expression of various molecules, suggesting a potential therapeutic strategy for the treatment of sepsis patients.

The effects of glucose concentrations associated with lipopolysaccharide and interferon-gamma stimulus on mediators' production of RAW 264.7 cells

Diabetes mellitus (DM) is a metabolic disorder that results in the impairment of the metabolism of carbohydrates, proteins and lipids. It can give rise to various complications, mainly caused by chronic exposure of cells to high glucose concentrations, including changes in the immune response processes. The aim of this study was to verify the chemokine and cytokines production profile in the presence of different glucose concentrations and infection/inflammatory stimuli. To this end, cell viability and the production of chemokines, cytokines and nitric oxide (NO) were analyzed in RAW 264.7 cell culture. Results demonstrated that there was no change in cell viability after 6, 24 and 72 h. Different stimuli were unable to modify the monocyte chemoattractant protein (MCP)-1 and tumor necrosis factor (TNF)-α production. Groups stimulated with lipopolysaccharides (LPS) and LPS and recombinant interferon (rIFN)-γ down-regulated interleukin (IL)-1α, IL-10 and IL-12 and up-regulated IL-6 production. NO production maintained a pattern of increase, according to the increase in glucose concentrations, reaching its peak at 72 h. In summary, the results demonstrated that high glucose concentrations alone may be sufficient to alter the in vitro mediators' production of RAW 264.7 cells.

TLR4 Signaling Pathway Modulators as Potential Therapeutics in Inflammation and Sepsis

Toll-Like Receptor 4 (TLR4) signal pathway plays an important role in initiating the innate immune response and its activation by bacterial endotoxin is responsible for chronic and acute inflammatory disorders that are becoming more and more frequent in developed countries. Modulation of the TLR4 pathway is a potential strategy to specifically target these pathologies. Among the diseases caused by TLR4 abnormal activation by bacterial endotoxin, sepsis is the most dangerous one because it is a life-threatening acute system inflammatory condition that still lacks specific pharmacological treatment. Here, we review molecules at a preclinical or clinical phase of development, that are active in inhibiting the TLR4-MyD88 and TLR4-TRIF pathways in animal models. These are low-molecular weight compounds of natural and synthetic origin that can be considered leads for drug development. The results of in vivo studies in the sepsis model and the mechanisms of action of drug leads are presented and critically discussed, evidencing the differences in treatment results from rodents to humans.