Effect of ω-3 polyunsaturated fatty acid on toll-like receptors in patients with severe multiple trauma

A Novel Cochlioquinone Derivative, CoB1, Regulates Autophagy in Pseudomonas aeruginosa Infection through the PAK1/Akt1/mTOR Signaling Pathway

Owing to multiple antibiotic resistance, Pseudomonas aeruginosa causes the most intractable infections to human beings worldwide, thus exploring novel drugs to defend against this bacterium remains of great importance. In this study, we purified a novel cochlioquinone B derivative (CoB1) from Salvia miltiorrhiza endophytic Bipolaris sorokiniana and reveal its role in host defense against P. aeruginosa infection by activating cytoprotective autophagy in alveolar macrophages (AMs) both in vivo and in vitro. Using a P. aeruginosa infection model, we observed that CoB1-treated mice manifest weakened lung injury, reduced bacterial systemic dissemination, decreased mortality, and dampened inflammatory responses, compared with the wild type littermates. We demonstrate that CoB1-induced autophagy in mouse AMs is associated with decreased PAK1 expression via the ubiquitination-mediated degradation pathway. The inhibition of PAK1 decreases the phosphorylation level of Akt, blocks the Akt/mTOR signaling pathway, and promotes the release of ULK1/2-Atg13-FIP200 complex from mTOR to initiate autophagosome formation, resulting in increased bacterial clearance capacity. Together, our results provide a molecular basis for the use of CoB1 to regulate host immune responses against P. aeruginosa infection and indicate that CoB1 is a potential option for the treatment of infection diseases.

Modulation of Toll-like receptor signaling in innate immunity by natural products

For centuries, natural products and their derivatives have provided a rich source of compounds for the development of new immunotherapies in the treatment of human disease. Many of these compounds are currently undergoing clinical trials, particularly as anti-oxidative, anti-microbial, and anti-cancer agents. However, the function and mechanism of natural products in how they interact with our immune system has yet to be extensively explored. Natural immune modulators may provide the key to control and ultimately defeat disorders affecting the immune system. They can either up- or down-regulate the immune response with few undesired adverse effects. In this review, we summarize the recent advancements made in utilizing natural products for immunomodulation and their important molecular targets, members of the Toll-like receptor (TLR) family, in the innate immune system.

Omega-3 polyunsaturated fatty acids inhibit the increase in cytokines and chemotactic factors induced in vitro by lymph fluid from an intestinal ischemia-reperfusion injury model

OBJECTIVE

To investigate the active factors and the intervention effect of ω-3 polyunsaturated fatty acids (PUFAs) during intestinal ischemia-reperfusion (I/R) injury, which causes the inflammation of monocytes-macrophages cultured in lymph fluid and stimulated with ω-3 PUFAs.

METHODS

Forty-eight Sprague-Dawley male rats were randomly divided into the following two groups: A. (N + D) group and B. (I/R + D) group. The rats in the (N + D) group were drained of lymph for 180 min; the rats in the (I/R + D) group were subjected to 60 min ischemia by clamping the superior mesenteric artery followed by 120 min reperfusion and 180 min of lymph draining. Lymph fluid from each group was further divided into 4 subgroups, respectively: lymph group (A1, B1); eicosopentaenoic acid (EPA)-treated group (A2, B2); EPA + docosahexaeonic acid (DHA)-treated group (A3, B3); and DHA-treated group (A4, B4), then cultured monocyte-macrophage cell line.

RESULTS

The levels of tumor necrosis factor-α, interleukin (IL)-1 β, IL-6, soluble cell adhesion molecule-1, chemotactic factors macrophage chemoattractant protein-1, macrophage inflammatory protein-2, and high mobility group box protein 1 in the B1 group were significantly higher than in the A1 group. Importantly, addition of EPA, EPA + DHA, and DHA to the culture media significantly reduced the levels of the above-mentioned factors. Cell stimulation with EPA, EPA + DHA, and DHA also significantly decreased the expression of Toll-like receptor 4, nuclear factor-κB p65, macrophage chemoattractant protein-1, and macrophage inflammatory protein-2 with the combined treatment of EPA and DHA showing the strongest effect.

CONCLUSIONS

The factors induced in lymph during intestinal I/R injury can cause inflammation in vitro. These data provide in vitro evidence that ω-3 PUFAs provide a protective effect by reducing the inflammatory response caused by intestinal I/R lymph. Moreover, the synergism of EPA and DHA had the greatest effect, which is possibly mediated through Toll-like receptor 4 and nuclear factor-κB p65.

Immunometabolic role of long-chain omega-3 fatty acids in obesity-induced inflammation

Inflammation links obesity with the development of insulin resistance. Macrophages and phagocytic immune cells communicate with metabolic tissues to direct an inflammatory response caused by overnutrition and expanding adipose tissue. Marine-derived omega-3 fatty acids, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), modulate inflammatory signalling events, providing various anti-inflammatory and cardioprotective benefits. Moreover, EPA and DHA may improve insulin sensitivity by generating proresolving lipid mediators and promoting alternatively activated macrophages. This review will assess the role of EPA and DHA in ameliorating obesity-induced inflammation, evaluating clinical evidence and mechanisms of action. The pathophysiology of insulin resistance resulting from obesity-induced inflammation will be discussed, highlighting the relationship between metabolism and immunity, and in particular, how EPA and DHA work with both systems to modulate immunometabolic complications and chronic disease.

The effects of n-3 PUFA and intestinal lymph drainage on high-mobility group box 1 and Toll-like receptor 4 mRNA in rats with intestinal ischaemia-reperfusion injury

The aim of the present study was to investigate the impacts of n-3 PUFA and lymph drainage (D) on intestinal ischaemia-reperfusion (I/R) injury in rats. A total of forty-eight Sprague-Dawley male rats were randomly divided into three groups (n 16): normal diet (N), enteral nutrition (EN) and EN plus n-3 PUFA. Each group was further divided into lymph drainage (I/R+D) and non-drainage (I/R) sub-groups (n 8). After 5 d with different nutrition regimens, the rats were subjected to 60 min ischaemia by clamping the superior mesenteric artery, followed by 120 min reperfusion. At the same time, the rats in the I/R+D sub-groups were treated with intestinal lymph drainage for 180 min. Organs were harvested and we detected the cytokine, endotoxin, and expression of Toll-like receptor (TLR) 4 mRNA and its endogenous ligand high-mobility group box 1 (HMGB1). We found that the serum levels of HMGB1, inflammatory cytokine and endotoxin in the three I/R+D sub-groups were significantly lower than those in the N (I/R) and EN (I/R) sub-groups (P < 0·05). The activation of NF-κB and the expression of HMGB1 and TLR4 mRNA significantly increased in the jejunum, ileum, liver and lung after intestinal I/R injury, but notably lower in the I/R+D groups than those in I/R (P < 0·05). The injury degree and HMGB1 expression were decreased in the n-3 PUFA group than in the N and EN groups. We preliminarily concluded that nutrition with n-3 PUFA and/or intestinal lymph drainage may reduce HMGB1 and inflammatory cytokine in serum and lymph and inhibit the expression and signal transmission of TLR4 mRNA, thereby alleviating intestinal I/R injury in rats.