Anti-Inflammatory Effects of Red Rice Bran Extract Ameliorate Type I Interferon Production via STING Pathway

Design, Synthesis, and Biological Assessment of Novel Aminobenzidazole Agonists Targeting the Stimulator of Interferon Genes (STING) Receptor Signaling Pathway for Oncology Immunotherapy

The activation of the STING-mediated signaling pathway leads to the secretion of type I interferon (IFN) and the activation of tumor-specific T cells. STING, a pattern recognition receptor located on the endoplasmic reticulum membrane of immune cells, binds with endogenous cyclic dinucleotides. STING undergoes phosphorylation, triggering the STING-TBK1-IRF3 pathway and NF-κB pathway, resulting in the release of IFN-β and other pro-inflammatory cytokines, ultimately enhancing the activation of tumor-specific T cells. This mechanism serves to complement the limitations of immune checkpoint inhibitors and enhances the efficiency of the immune response. This study selected benzimidazole compounds GSK and SR-717, which exhibit promising potential as patented medicines, as our lead compounds. Aiming to address the challenges associated with the short half-life of benzimidazole compounds and the limited molecular activity of SR-717, we designed and synthesized a series of STING agonists (compounds 6~29). The compound 17 showed excellent agonistic activity on hSTING protein in vitro. The cytotoxicity tests of all the synthesized compounds were performed in vitro. Performed in vivo pharmacokinetic studies on the most promising compounds and conducted molecular docking analyses.

Elaeagnus latifolia Fruit Extract Ameliorates High-Fat Diet-Induced Obesity in Mice and Alleviates Macrophage-Induced Inflammation in Adipocytes In Vitro

Elaeagnus latifolia (EL) is a wild fruit known for containing several health-promoting compounds. This study aimed to evaluate the effects of EL fruit extract on high-fat diet (HFD)-induced obesity and lipopolysaccharide (LPS)-activated macrophages. Mice fed an HFD and given EL fruit extract for 10 weeks exhibited significantly lower body weight, reduced lipid accumulation, diminished oxidative stress in adipocytes, and decreased macrophage infiltration compared to those not receiving the EL extract. Moreover, the EL fruit extract activated the transcription factors Pparg and Cebpa, initiating adipogenesis and modulating the expression of NF-κB/Nrf-2-induced target genes. This resulted in smaller adipocyte size, reduced inflammation, and less oxidative stress in HFD-fed mice. In vitro, the EL extract induced a shift in macrophage phenotype from M1 to M2, reduced IκBα/NF-κB phosphorylation, and effectively decreased energy production in macrophages by downregulating the expression of several proteins involved in glycolysis and the tricarboxylic acid cycle. This mechanistic study suggests that administering EL fruit extract could be an effective strategy for managing obesity and its associated pathologies.

Enzyme-treated red rice (Oryza sativa L.) bran extracts mitigate inflammatory markers in RAW 264.7 macrophage cells and exhibit anti-inflammatory efficacy greater/comparable to ferulic acid, catechin, γ-tocopherol, and γ-oryzanol

ETHNOPHARMACOLOGICAL RELEVANCE

Rice (Oryza sativa L.), a staple food for a significant portion of the global population, has been recognized for its traditional medicinal properties for centuries. Rice bran, a by-product of rice milling, contains many bioactive compounds with potential pharmaceutical and therapeutic benefits. In recent years, research has highlighted the anti-inflammatory potential of rice bran, contributed by the bioactive components concentrated in their bran but, unfortunately, entrapped in the bran matrix, with limited bioavailability. Previous studies have reported that the enzymatic treatment of rice bran improves the bran's bioactive compound profile but did not investigate its impact on chronic conditions such as inflammation.

AIM OF THE STUDY

This study investigates the anti-inflammatory effects of endo-1,4-β-xylanase (ERB) and Viscozyme (VRB) treated red rice bran extracts against lipopolysaccharide-induced inflammation in RAW264.7 macrophages in comparison with non-enzyme-treated bran (CRB). Further established their efficacy with known anti-inflammatory compounds-ferulic acid (FA), catechin (CAT), γ-tocopherol (GTP), and γ-oryzanol (ORZ).

MATERIALS AND METHODS

The RAW 264.7 macrophage cells were pre-treated with non-toxic concentrations (10-200 μg/mL) of FA, CAT, GTP, ORZ, CRB, ERB, and VRB, followed by inflammatory stimulation with LPS for 24 h. Further, the cell supernatant and pellets were harvested to study the anti-inflammatory effects by evaluating and measuring their efficacy in inhibiting pro-inflammatory cytokines (TNF-α, IL-6, IL-10, IL-1β) and mediators (ROS, NO, PGE2, COX2, iNOS) through biochemical, ELISA, and mRNA expression studies.

RESULTS

The findings showed that both ERB and VRB effectively inhibited the production of pro-inflammatory markers (TNF-α, IL-6) and mediators (ROS, NO, PGE2) by downregulating mRNA expressions of inflammatory genes (TNF-α, IL-1β, IL-6, IL-10, COX2, iNOS) and demonstrated anti-inflammatory efficacy higher than CRB. On comparison, ERB demonstrated exceptional efficacy by causing a reduction of 48% in ROS, 20% in TNF-α, and 23% in PGE2 at 10 μg/mL, surpassing the anti-inflammatory capabilities of all the bioactive compounds, FA and ORZ, respectively. At the same time, VRB exhibited remarkable efficacy by reducing NO production by 52% at 200 μg/mL and IL-6 by 66% at 10 μg/mL, surpassing FA, CAT, ORZ, and GTP. Further, ERB downregulated the mRNA expression of IL-10 and iNOS, while VRB downregulated TNF-α, IL-1β, and COX2 expression. Both extracts equally downregulated IL-6 expression at 10 μg/mL, demonstrating the efficacy more remarkable/on par with established anti-inflammatory compounds.

CONCLUSIONS

Overall, enzyme-treated rice bran/extract, particularly ERB, possesses excellent anti-inflammatory properties, making them promising agents for alternatives to contemporary nutraceuticals/functional food against inflammatory diseases.

Perillaldehyde ameliorates lipopolysaccharide-induced acute lung injury via suppressing the cGAS/STING signaling pathway

Acute lung injury (ALI) is a common life-threatening illness characterized by a lung inflammatory response and oxidative stress, and effective agent therapies are currently lacking. mtDNA can be recognized by cGAS/STING, the dysregulation of which leads to inflammatory diseases, such as ALI. Perillaldehyde(PAH), one of the major active components of traditional Chinese medicine made from Perilla frutescens, has antioxidant and antiinflammatory effects. The aim of this study was to explore whether PAH can protect against lipopolysaccharide (LPS)-induced ALI and whether its protective effect is exerted through the regulation of cGAS/STING signaling. We found that PAH significantly inhibited lung histological changes, inflammatory cell infiltration, and the overproduction of inflammatory cytokines induced by LPS. Moreover, PAH inhibited LPS-induced oxidative stress, as shown by the deceases in superoxide dismutase (SOD) and glutathione(GSH) levels and increased in malondialdehyde (MDA) and lactate dehydrogenase (LDH) levels. In addition, PAH markedly downregulated the expression of cGAS, STING, p-TBK, p-IRF3, p-P65, and p-IκB, and pharmacological inhibition of cGAS/STING inhibited ALI- induced by LPS. Furthermore, the levels of mitochondrial ROS (mROS) and mtDNA were increased, and cGAS/STING-mediated IRF3/NF-κB signaling was activated during the inflammatory response- induced by LPS in RAW264.7 cells. In addition, pretreatment with the STING activator partially abolished the inhibitory effect of PAH on the inflammation and activation of STING-mediated IRF3/NF-κB signaling induced by LPS. Overall, the results revealed that PAH can effectively alleviate ALI by inhibiting cGAS/STING-mediated IRF3/NF-κB signaling, and that PAH may be a potential candidate agent for the treatment of ALI.

The crucial regulatory role of type I interferon in inflammatory diseases

Type I interferon (IFN-I) plays crucial roles in the regulation of inflammation and it is associated with various inflammatory diseases including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and periodontitis, impacting people's health and quality of life. It is well-established that IFN-Is affect immune responses and inflammatory factors by regulating some signaling. However, currently, there is no comprehensive overview of the crucial regulatory role of IFN-I in distinctive pathways as well as associated inflammatory diseases. This review aims to provide a narrative of the involvement of IFN-I in different signaling pathways, mainly mediating the related key factors with specific targets in the pathways and signaling cascades to influence the progression of inflammatory diseases. As such, we suggested that IFN-Is induce inflammatory regulation through the stimulation of certain factors in signaling pathways, which displays possible efficient treatment methods and provides a reference for the precise control of inflammatory diseases.

Effects of Pogonatherum paniceum (Lamk) Hack extract on anti-mitochondrial DNA mediated inflammation by attenuating Tlr9 expression in LPS-induced macrophages

BACKGROUND/OBJECTIVES

Mitochondrial DNA leakage leads to inflammatory responses via endosome activation. This study aims to evaluate whether the perennial grass water extract (Pogonatherum panicum) ameliorate mitochondrial DNA (mtDNA) leakage.

MATERIALS/METHODS

The major bioactive constituents of P. paniceum (PPW) were investigated by high-performance liquid chromatography, after which their antioxidant activities were assessed. In addition, RAW 264.7 macrophages were stimulated with lipopolysaccharide, resulting in mitochondrial damage. Quantitative polymerase chain reaction and enzyme-linked immunosorbent assay were used to examine the gene expression and cytokines.

RESULTS

Our results showed that PPW extract-treated activated cells significantly decrease reactive oxygen species and nitric oxide levels by reducing the p22phox and iNOS expression and lowering cytokine-encoding genes, including IL-6, TNF-α, IL-1β, PG-E2 and IFN-γ relative to the lipopolysaccharide (LPS)-activated macrophages. Furthermore, we observed that LPS enhanced the mtDNA leaked into the cytoplasm, increasing the transcription of Tlr9 and signaling both MyD88/Irf7-dependent interferon and MyD88/NF-κb p65-dependent inflammatory cytokine mRNA expression but which was alleviated in the presence of PPW extract.

CONCLUSIONS

Our data show that PPW extract has antioxidant and anti-inflammatory activities by facilitating mtDNA leakage and lowering the Tlr9 expression and signaling activation.

Mannose-Coated Reconstituted Lipoprotein Nanoparticles for the Targeting of Tumor-Associated Macrophages: Optimization, Characterization, and In Vitro Evaluation of Effectiveness

Reconstituted high-density lipoprotein nanoparticles (rHDL NPs) have been utilized as delivery vehicles to a variety of targets, including cancer cells. However, the modification of rHDL NPs for the targeting of the pro-tumoral tumor-associated macrophages (TAMs) remains largely unexplored. The presence of mannose on nanoparticles can facilitate the targeting of TAMs which highly express the mannose receptor at their surface. Here, we optimized and characterized mannose-coated rHDL NPs loaded with 5,6-dimethylxanthenone-4-acetic acid (DMXAA), an immunomodulatory drug. Lipids, recombinant apolipoprotein A-I, DMXAA, and different amounts of DSPE-PEG-mannose (DPM) were combined to assemble rHDL-DPM-DMXAA NPs. The introduction of DPM in the nanoparticle assembly altered the particle size, zeta potential, elution pattern, and DMXAA entrapment efficiency of the rHDL NPs. Collectively, the changes in physicochemical characteristics of rHDL NPs upon the addition of the mannose moiety DPM indicated that the rHDL-DPM-DMXAA NPs were successfully assembled. The rHDL-DPM-DMXAA NPs induced an immunostimulatory phenotype in macrophages pre-exposed to cancer cell-conditioned media. Furthermore, rHDL-DPM NPs delivered their payload more readily to macrophages than cancer cells. Considering the effects of the rHDL-DPM-DMXAA NPs on macrophages, the rHDL-DPM NPs have the potential to serve as a drug delivery platform for the selective targeting of TAMs.

Red Rice Bran Extract Alleviates High-Fat Diet-Induced Non-Alcoholic Fatty Liver Disease and Dyslipidemia in Mice

Red rice bran extract (RRBE) is rich in phytonutrients and has been shown to have anti-diabetic, anti-inflammatory, and antioxidant properties. However, its anti-hepatic steatosis and anti-dyslipidemic properties have not been thoroughly investigated. This study examined the aforementioned properties of RRBE, the underlying mechanism by which it alleviated non-alcoholic fatty liver disease in high-fat diet (HFD)-fed mice, and its major bioactive constituents. The mice were divided into four groups based on their diet: (1) low-fat diet (LFD), (2) LFD with high-dose RRBE (1 g/kg/day), (3) HFD, and (4) HFD with three different doses of RRBE (0.25, 0.5, and 1 g/kg/day). The administration of RRBE, especially at medium and high doses, significantly mitigated HFD-induced hepatosteatosis and concomitantly improved the serum lipid profile. Further, RRBE modified the level of expression of lipid metabolism-related genes (adipose triglyceride lipase (ATGL), cluster of differentiation 36 (CD36), lipoprotein lipase (LPL), liver X receptor alpha (LXRα), sterol regulatory element-binding protein-1c (SREBP-1c), SREBP-2, 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), and carnitine palmitoyltransferase 1A (CPT1A)) in hepatic or adipose tissues and improved the expression of hepatic high-density lipoprotein cholesterol (HDL-C) cmetabolism-related genes (hepatic lipase (HL) and apolipoprotein A-ǀ (ApoA-ǀ)). RRBE also attenuated markers of liver injury, inflammation, and oxidative stress, accompanied by a modulated expression of inflammatory (nuclear factor-kappa B (NF-κB) and inducible nitric oxide synthase (iNOS)), pro-oxidant (p47^phox), and apoptotic (B-cell lymphoma protein 2 (Bcl-2)-associated X and Bcl-2) genes in the liver. High-performance liquid chromatography analyses indicated the presence of protocatechuic acid, γ-oryzanol, vitamin E, and coenzyme Q10 in RRBE. Our data indicate that RRBE alleviates HFD-induced hepatosteatosis, dyslipidemia, and their pathologic complications in part by regulating the expression of key genes involved in lipid metabolism, inflammation, oxidative stress, and apoptosis.