10-hydroxy-2-decenoic acid a bio-immunomodulator in tissue engineering; generates tolerogenic dendritic cells by blocking the toll-like receptor4

10-Hydroxydec-2-enoic acid reduces vascular smooth muscle cell inflammation via interacting with Toll-like receptor 4

BACKGROUND

10-Hydroxydec-2-enoic acid (10-HDA), a unique and marker compound in royal jelly, has a wide range of bio-activities. However, its role in regulating inflammation of vascular smooth muscle cell (VSMC), which is essential to a set of vascular diseases, is still unknown.

PURPOSE

Our study aimed to investigate whether 10-HDA exerts effect on VSMC inflammation via interacting with toll-like receptor 4 (TLR4), a pivotal inflammatory initiator.

METHODS

A package of proteins, which might participate in TLR4-mediated signaling, influenced by 10-HDA were analyzed in mouse VSMCs with Angiotensin Ⅱ(Ang Ⅱ) or lipopolysaccharide (LPS) stimulation. Accordingly, pro- or anti-inflammatory cytokines, reactive oxygen species (ROS), and anti-oxidants that are closely relevant to inflammatory process were determined. The possible mode for 10-HDA interacting with TLR4 was also characterized. Moreover, involvement of a key miRNA in 10-HDA regulating VSMC inflammation was identified.

RESULTS

In the presence of Ang Ⅱ, 10-HDA inhibited the TLR4 expression in a dose-dependent manner. In such occasion, 10-HDA hindered the up-regulation of specificity protein 1 (SP1) and serine/threonine-protein phosphatase 6 catalytic subunit (PPP6C), the phosphorylation of extracellular signal-regulated kinase 1/2, TGF-β-activated kinase 1, and nuclear factor-κB p56, as well as the enhancement of myeloid differentiation primary response gene 88. Apart from SP1 and PPP6C, the level change of these proteins by 10-HDA was similar with LPS stimulation. The effect might be resulted from 10-HDA blocking TLR4 through multiple atomic interactions. 10-HDA mitigated the increase of pro-inflammatory cytokines tumor necrosis factor-alpha, interleukin-2 (IL-2), and IL-6, as well as increased the anti-inflammatory cytokine IL-10, in the Ang Ⅱ- or LPS-induced VSMCs. Correspondingly, the level of ROS was attenuated and the anti-oxidants such as glutathione and superoxide dismutase were fortified. The data indicated the anti-inflammatory potential of 10-HDA in VSMCs, which was associated with 10-HDA's capability of relieving oxidative stress. Additionally, the expression of miR-17-5p was saved by 10-HDA from Ang Ⅱ- or LPS-treated VSMCs, which might be relevant to SP1 and PPP6C targeting.

CONCLUSION

The present work of 10-HDA, for the first time, revealed its ability to alleviate VSMC inflammation by targeting TLR4 and therefore modulate the downstream inflammatory participants. Our data will cast light on the utilization of 10-HDA in VSMC inflammation-related vascular disorders.

Asymmetric natural wound dressing based on porous chitosan-alginate hydrogel/electrospun PCL-silk sericin loaded by 10-HDA for skin wound healing: In vitro and in vivo studies

An asymmetric wound dressing introduced, inspired by the skin structure made of chitosan and alginate hydrogel as the bottom layer and electrospun PCL-silk sericin (PCL-SS) as the top layer. In addition, an anti-inflammatory, bactericidal and immunomodulatory substance, 10-hydroxydecanoic acid (10-HDA), known as queen bee acid, was loaded in inner layer. The wound dressing was thoroughly characterized and confirmed to meet the criteria of a standard wound dressing through in vitro and in vivo studies. Although the mesoporous hydrogel layer shows 175 % swelling after being immersed in PBS (pH = 7.4) for 60 min and 80 % degradation after 14 days, the top layer shows 28 % swelling and 19 % degradation in the same time intervals. The hydrogel layer supports rapid wound healing, while the top layer offers protection against infection and physical threats. The dressing demonstrated antibacterial properties and enhanced cell proliferation at 1 % 10-HDA. Finally, the wound healing performance of the complete dressing was investigated in vivo using wistar rat. Clinical and histopathological assessments, along with the analysis of biophysical parameters of the skin healing, confirm that wound dressing with 10-HDA significantly accelerates wound healing compared to control groups, without any inflammatory side effects.

Cationic nanoparticles-based approaches for immune tolerance induction in vivo

The development of autoimmune diseases and the rejection of transplanted organs are primarily caused by an exaggerated immune response to autoantigens or graft antigens. Achieving immune tolerance is crucial for the effective treatment of these conditions. However, traditional therapies often have limited therapeutic efficacy and can result in systemic toxic effects. The emergence of nanomedicine offers a promising avenue for addressing immune-related diseases. Among the various nanoparticle formulations, cationic nanoparticles have demonstrated significant potential in inducing immune tolerance. In this review, we provide an overview of the underlying mechanism of autoimmune disease and organ transplantation rejection. We then highlight the recent advancements and advantages of utilizing cationic nanoparticles for inducing immune tolerance in the treatment of autoimmune diseases and the prevention of transplant rejection.

Metabolic Profile of Alzheimer's Disease: Is 10-Hydroxy-2-decenoic Acid a Pertinent Metabolic Adjuster?

Alzheimer's disease (AD) represents a significant public health concern in modern society. Metabolic syndrome (MetS), which includes diabetes mellitus (DM) and obesity, represents a modifiable risk factor for AD. MetS and AD are interconnected through various mechanisms, such as mitochondrial dysfunction, oxidative stress, insulin resistance (IR), vascular impairment, inflammation, and endoplasmic reticulum (ER) stress. Therefore, it is necessary to seek a multi-targeted and safer approach to intervention. Thus, 10-hydroxy-2-decenoic acid (10-HDA), a unique hydroxy fatty acid in royal jelly, has shown promising anti-neuroinflammatory, blood-brain barrier (BBB)-preserving, and neurogenesis-promoting properties. In this paper, we provide a summary of the relationship between MetS and AD, together with an introduction to 10-HDA as a potential intervention nutrient. In addition, molecular docking is performed to explore the metabolic tuning properties of 10-HDA with associated macromolecules such as GLP-1R, PPARs, GSK-3, and TREM2. In conclusion, there is a close relationship between AD and MetS, and 10-HDA shows potential as a beneficial nutritional intervention for both AD and MetS.

A label-free SPR biosensor for specific detection of TLR4 expression; introducing of 10-HDA as an antagonist

Toll-like receptor 4 (TLR4) is actively involved in many health-related problems, including transplantation rejection and autoimmune diseases. Therefore, it is important to identify an antagonist to inhibit the TLR4-induced immune cell activation. In our previous study, 10-hydroxy-2-decanoic acid (10-HDA) was introduced as a potential antagonist for TLR4; however, possible interaction between 10-HDA and TLR4 needed to be detected. Due to the ability of surface plasmon resonance (SPR) biosensor to confirm the specific interactions between receptors and ligands, a new configuration of SPR biosensor proposed to detect the possible interaction between 10-HDA and TLR4. Hence, 10-HDA was immobilized using the (3-aminopropyl) triethoxysilane (APTES) polymer as a crosslinking agent on the Ag-MgF₂ surface. Besides, genetically modified HEK293T cells with high TLR4 expression were used to study the possible interaction between 10-HDA and TLR4. Surprisingly, the SPR angle was significantly reduced in the presence of HEK cells expressing TLR4, while HEK cells without TLR4 did not affect the SPR angle. So, the proposed SPR biosensor successfully detected the interaction betweenTLR4 and 10-HDA. The sensitivity and detection limit of the biosensor were achieved at 0.05 and 0.5 million cells expressing TLR4, respectively, with a two-fold dynamic range.

trans 10, cis 12, but Not cis 9, trans 11 Conjugated Linoleic Acid Isomer Enhances Exercise Endurance by Increasing Oxidative Skeletal Muscle Fiber Type via Toll-like Receptor 4 Signaling in Mice

Conjugated linoleic acid (CLA) has been implicated in regulating muscle fiber. However, which isomer elicits this effect and the underlying mechanisms remain unclear. Here, male C57BL6/J mice and C2C12 cells were treated with two CLA isomers, and the exercise endurance, skeletal muscle fiber type, and involvement of Toll-like receptor 4 (TLR4) signaling were assessed. The results demonstrated that dietary t10, c12, but not c9, t11-CLA isomer enhanced exercise endurance of mice (from 115.88 ± 11.21 to 130.00 ± 15.84 min, P < 0.05) and promoted the formation of oxidative muscle fiber type of gastrocnemius muscle (from 0.15 ± 0.04 to 0.24 ± 0.05, P < 0.05). Consistently, t10, c12-CLA isomer increased the mRNA expression of oxidative muscle fiber type in C2C12 myotubes (from 1.00 ± 0.08 to 2.65 ± 1.77, P < 0.05). In addition, t10, c12-CLA isomer increased TLR4 signaling expression in skeletal muscle and C2C12 myotubes. More importantly, knockdown of TLR4 eliminated the t10, c12-CLA isomer-induced enhancement of exercise endurance in mice and elevation of oxidative muscle fiber type in C2C12 myotubes and gastrocnemius muscle. Together, these findings showed that t10, c12, but not c9, t11-CLA isomer enhances exercise endurance by increasing oxidative skeletal muscle fiber type via TLR4 signaling.