Liposome-Mediated Inhibition of Inflammation by Hydroxycitrate

Discovery and characterization of novel ATP citrate lyase inhibitors from Acanthopanax senticosus (Rupr. & Maxim.) Harms

ATP citrate lyase (ACLY) is a key enzyme in glucolipid metabolism, and abnormally high expression of ACLY occurs in many diseases, including cancers, dyslipidemia and cardiovascular diseases. ACLY inhibitors are prospective treatments for these diseases. However, the scaffolds of ACLY inhibitors are insufficient with weak activity. The discovery of inhibitors with structural novelty and high activity continues to be a research hotpot. Acanthopanax senticosus (Rupr. & Maxim.) Harms is used for cardiovascular disease treatment, from which no ACLY inhibitors have ever been found. In this work, we discovered three novel ACLY inhibitors, and the most potent one was isochlorogenic acid C (ICC) with an IC50 value of 0.14 ± 0.04 μM. We found dicaffeoylquinic acids with ortho-dihydroxyphenyl groups were important features for inhibition by studying ten phenolic acids. We further investigated interactions between the highly active compound ICC and ACLY. Thermal shift assay revealed that ICC could directly bind to ACLY and improve its stability in the heating process. Enzymatic kinetic studies indicated ICC was a noncompetitive inhibitor of ACLY. Our work discovered novel ACLY inhibitors, provided valuable structure-activity patterns and deepened knowledge on the interactions between this targe tand its inhibitors.

Aquaporins (AQPs) as a marker in the physiology of inflammation and its interaction studies with garcinol

Aquaporins like AQP1, AQP3, and AQP4 are known to be involved in the pathophysiology of inflammation based on earlier reports. This study aimed to evaluate the involvement of Aquaporins as a potential target of inflammation. The study also investigates the efficacy of methanolic extract of Garcinia (GME) and its potent phytocompound (garcinol) against the Aquaporins involved in inflammation. siRNA silencing of AQP3 was carried out in RAW264.7 cells followed by LPS stimulation (1 µg/ml) and assessment of important markers of inflammation including NO, PGE2, TNF-α, IL-6, IL-1β, CCL20, iNOS and COX-2. To assess the anti-inflammatory potential of Garcinia extract and garcinol, cells were stimulated with 1 µg/ml LPS in the absence and presence of increasing concentrations of GME and garcinol. During the experimental period, extract concentrations (115 µg/ml and 230 µg/ml for RAW264.7; 118 µg/ml and 236 µg/ml for THP-1) and garcinol concentrations (6 µM and 12 µM for RAW264.7; 3 µM and 6 µM for THP-1) were selected based on the IC50. The anti-inflammatory effects were assessed by measuring the levels of TNF-α, IL-1β, IL-6, and CCL20 in LPS-stimulated cells. The AQP expression was studied at transcriptional and translational levels using qPCR and Western blot analysis respectively. AQP3 knockdown significantly decreased the NO, PGE2, TNF-α, IL-1β levels along with iNOS and COX-2 mRNA expression. LPS stimulation led to a significant increase in the mRNA and protein level expression AQP1, AQP3, and AQP4 in RAW264.7 cells; and AQP1 and AQP3 in THP-1 cells indicating their role as markers of inflammation. GME and garcinol effectively suppressed the LPS-induced proinflammatory cytokine production in both cell lines. The results indicate that AQP1, AQP3, and AQP4 could play a crucial role as markers of inflammation. Anti-inflammatory agents like Garcinia could potentially decrease the expression of such AQPs, thus inhibiting the inflammatory process.

ACLY as a modulator of liver cell functions and its role in Metabolic Dysfunction-Associated Steatohepatitis

BACKGROUND

Non-alcoholic Fatty Liver Disease (NAFLD), now better known as Metabolic (Dysfunction)-Associated Fatty Liver Disease (MAFLD) and its progression to Nonalcoholic Steatohepatitis (NASH), more recently referred to as Metabolic (Dysfunction)-Associated Steatohepatitis (MASH) are the most common causes of liver failure and chronic liver damage. The new names emphasize the metabolic involvement both in relation to liver function and pathological features with extrahepatic manifestations. This study aims to explore the role of the immunometabolic enzyme ATP citrate lyase (ACLY), with a critical function in lipogenesis, carbohydrate metabolism, gene expression and inflammation.

METHODS

ACLY function was investigated in TNFα-triggered human hepatocytes and in PBMC-derived macrophages from MASH patients. Evaluation of expression levels was carried out by western blotting and/or RT-qPCR. In the presence or absence of ACLY inhibitors, ROS, lipid peroxidation and GSSG oxidative stress biomarkers were quantified. Chromatin immunoprecipitation (ChIP), transient transfections, immunocytochemistry, histone acetylation quantitation were used to investigate ACLY function in gene expression reprogramming. IL-6 and IL-1β were quantified by Lumit immunoassays.

RESULTS

Mechanistically, ACLY inhibition reverted lipid accumulation and oxidative damage while reduced secretion of inflammatory cytokines in TNFα-triggered human hepatocytes. These effects impacted not only on lipid metabolism but also on other crucial features of liver function such as redox status and production of inflammatory mediators. Moreover, ACLY mRNA levels together with those of malic enzyme 1 (ME1) increased in human PBMC-derived macrophages from MASH patients when compared to age-matched healthy controls. Remarkably, a combination of hydroxycitrate (HCA), the natural ACLY inhibitor, with red wine powder (RWP) significantly lowered ACLY and ME1 mRNA amount as well as IL-6 and IL-1β production in macrophages from subjects with MASH.

CONCLUSION

Collectively, our findings for the first time highlight a broad spectrum of ACLY functions in liver as well as in the pathogenesis of MASH and its diagnostic and therapeutic potential value.

PEGylated Liposomes Loaded with Carbamate Inhibitor ANP0903 Trigger Apoptosis by Enhancing ER Stress in HepG2 Cancer Cells

Liver cancer is one of the most common causes of cancer death worldwide. In recent years, substantial progress has been made in the development of systemic therapies, but there is still the need for new drugs and technologies that can increase the survival and quality of life of patients. The present investigation reports the development of a liposomal formulation of a carbamate molecule, reported as ANP0903, previously tested as an inhibitor of HIV-1 protease and now evaluated for its ability to induce cytotoxicity in hepatocellular carcinoma cell lines. PEGylated liposomes were prepared and characterized. Small, oligolamellar vesicles were produced, as demonstrated by light scattering results and TEM images. The physical stability of the vesicles in biological fluids was demonstrated in vitro, alongside the stability during storage. An enhanced cellular uptake was verified in HepG2 cells treated with liposomal ANP0903, resulting in a greater cytotoxicity. Several biological assays were performed to elucidate the molecular mechanisms explaining the proapoptotic effect of ANP0903. Our results allow us to hypothesize that the cytotoxic action in tumor cells is probably due to the inhibition of the proteasome, resulting in an increase in the amount of ubiquitinated proteins within the cells, which in turn triggers activation of autophagy and apoptosis processes, resulting in cell death. The proposed liposomal formulation represents a promising approach to deliver a novel antitumor agent to cancer cells and enhance its activity.

Recent Advances in Garcinia cambogia Nutraceuticals in Relation to Its Hydroxy Citric Acid Level. A Comprehensive Review of Its Bioactive Production, Formulation, and Analysis with Future Perspectives

Garcinia cambogia (Gaertn.) Desr. (known as Malabar tamarind) is a popular traditional herbal medicine and is one of the well-known folk medicines reported for the treatment of obesity and incorporated in several nutraceuticals worldwide. These effects are mediated by a myriad of bioactive compounds with most effects attributed to its hydroxy citric acid (HCA) content. This review aims to present a holistic overview on novel trends in the production of G. cambogia bioactive components and how extraction optimization is important to ensure best product quality with its reported nanoformulations with particular emphasis on HCA content. Further, an overview of the different analytical approaches used for quality control assessment of G. cambogia plant and its nutraceuticals is presented highlighting both advantages and limitations. Moreover, analytical approaches for detecting G. cambogia metabolites in biological fluids with emphasis on HCA level to determine its pharmacokinetics and proof of efficacy are presented for the first time.

The effect of hydroxy citric acid supplementation with calorie-restricted diet on metabolic, atherogenic and inflammatory biomarkers in women with non-alcoholic fatty liver disease: a randomized controlled clinical trial

The objective of the present study was to examine the effects of hydroxy citric acid (HCA) extracts from Garcinia cambogia on metabolic, atherogenic and inflammatory biomarkers in obese women with non-alcoholic fatty liver disease (NAFLD). The present clinical trial was carried out on 40 overweight/obese women with NAFLD. The patients were randomly allocated into either the "HCA group" (receiving calorie-restricted diet (-700 kcal d^-1) accompanied by HCA tablets) and the "control group" (receiving only calorie-restricted diet) for eight weeks. Weight, height, body mass index (BMI), and waist circumference (WC) were measured. Fasting blood sugar (FBS), lipid profile, liver enzymes, as well as inflammatory biomarkers were determined at baseline and after the intervention. Dietary intake was assessed at baseline and at the end of the trial and food intake data were analyzed by the Nutritionist IV software. Results showed a decrease in energy and macronutrient intake in both groups (p < 0.05). Weight, BMI, WC, and hip circumference as well as FBS, triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) decreased and high-density lipoprotein cholesterol (HDL-C) increased significantly in the HCA group (p < 0.05). There were also significant reductions in WC, FBS, TG, total cholesterol, LDL-C in the control group while inter-group changes in FBS, TG, LDL-C and HDL-C were statistically significant. Although atherogenic indices reduced significantly in both groups, inter-group comparison revealed that the HCA group showed greater decrease in the TG/HDL-C ratio than the control group (p = 0.004). Other atherogenic indices including TC/HDL-C and non-HDL-C/HDL-C ratio showed greater reduction in the control versus HCA group (p < 0.01). Some inflammatory factors were reduced in the HCA group; however, no significant within- or between-group differences were revealed post-intervention. Our results indicated that HCA supplementation plus calorie-restricted diet could improve some metabolic factors without any significant effect on inflammation in patients with NAFLD.

Role of Lipogenesis Rewiring in Hepatocellular Carcinoma

Metabolic rewiring is one of the hallmarks of cancer. Altered de novo lipogenesis is one of the pivotal metabolic events deregulated in cancers. Sterol regulatory element-binding transcription factor 1 (SREBP1) controls the transcription of major enzymes involved in de novo lipogenesis, including ACLY, ACACA, FASN, and SCD. Studies have shown the increased de novo lipogenesis in human hepatocellular carcinoma (HCC) samples. Multiple mechanisms, such as activation of the AKT/mechanistic target of rapamycin (mTOR) pathway, lead to high SREBP1 induction and the coordinated enhanced expression of ACLY, ACACA, FASN, and SCD genes. Subsequent functional analyses have unraveled these enzymes' critical role(s) and the related de novo lipogenesis in hepatocarcinogenesis. Importantly, targeting these molecules might be a promising strategy for HCC treatment. This paper comprehensively summarizes de novo lipogenesis rewiring in HCC and how this pathway might be therapeutically targeted.

ACLY Nuclear Translocation in Human Macrophages Drives Proinflammatory Gene Expression by NF-κB Acetylation

Macrophage stimulation by pathogen-associated molecular patterns (PAMPs) like lipopolysaccharide (LPS) or lipoteichoic acid (LTA) drives a proinflammatory phenotype and induces a metabolic reprogramming to sustain the cell’s function. Nevertheless, the relationship between metabolic shifts and gene expression remains poorly explored. In this context, the metabolic enzyme ATP citrate lyase (ACLY), the producer of citrate-derived acetyl-coenzyme A (CoA), plays a critical role in supporting a proinflammatory response. Through immunocytochemistry and cytosol–nucleus fractionation, we found a short-term ACLY nuclear translocation. Protein immunoprecipitation unveiled the role of nuclear ACLY in NF-κB acetylation and in turn its full activation in human PBMC-derived macrophages. Notably, sepsis in the early hyperinflammatory phase triggers ACLY-mediated NF-κB acetylation. The ACLY/NF-κB axis increases the expression levels of proinflammatory genes, including SLC25A1—which encodes the mitochondrial citrate carrier—and ACLY, thus promoting the existence of a proinflammatory loop involving SLC25A1 and ACLY genes.

Exploiting the Anti-Inflammatory Potential of White Capsicum Extract by the Nanoformulation in Phospholipid Vesicles

The peppers of the Capsicum species are exploited in many fields, as flavoring agents in food industry, or as decorative and therapeutic plants. Peppers show a diversified phytochemical content responsible for different biological activities. Synergic activity exerted by high levels of antioxidant compounds is responsible for their important anti-inflammatory property. A methanolic extract was obtained from a new pepper genotype and tested for anti-inflammatory activity. The extract was incorporated into phospholipid vesicles to increase the bioavailability of its bioactive components. Two types of phospholipid vesicles were produced, conventional liposomes and Penetration Enhancer containing Vesicles (PEVs). They were tested in human monoblastic leukemia U937 cell line, showing no cytotoxic effect. The intracellular reactive oxygen species (ROS) and nitric oxide (NO) levels were measured to value the in vitro efficacy of the vesicles in regulating inflammatory responses. Liposomal incorporation significantly reduced ROS levels in extract-treated LPS-activated cells. Furthermore, LC-MS/MS analyses demonstrated that liposomes facilitated the transport of the extract components across the cell membrane and their accumulation into the cytoplasm.

Synthesis of new methoxy derivatives of trans 2,3-diaryl-2,3-dihydrobenzofurans and evaluation of their anti-inflammatory activity

In the present study we synthesized new methoxy derivatives of trans 2,3-diaryl-2,3-dihydrobenzofurans, starting from suitable trans 2,3-diaryloxiranes, using regio- and stereoselective nucleophilic oxiranyl ring-opening reactions. The compounds were tested as anti-inflammatories in U937 cells. All compounds showed a significant role in inhibiting the NF-κB pathway and were able to restore normal ROS and NO level upon LPS activation. Moreover, regarding inhibition of ACLY, enantioenriched (50% ee) 7a₅₀ showed more potency than the racemic counterpart 7arac, together with a higher reduction of prostaglandin E₂ production, thus suggesting a stereoselective interaction in this pathway.

Exploring the role of Aquaporins (AQPs) in LPS induced systemic inflammation and the ameliorative effect of Garcinia in male Wistar rat

The Aquaporins (AQPs) could prove to be striking targets of inflammation. The aim of this study was to study the involvement of AQPs and explore the anti-inflammatory activity of Garcinia extract in LPS induced acute systemic inflammation in Wistar rats. Adult male Wistar rats (n = 6) were pretreated with Garcinia orally twice for 7 days, followed by a single intraperitoneal dose (5.5 mg/kgbw) of LPS. Serum ALT, AST, ALP, Creatinine, Urea and BUN, nitric oxide, prostaglandin, cytokine and chemokine levels were measured. LC-MS analysis of Garcinia was performed to identify the phytoconstituents present. The iNOS and COX enzyme activity were determined in the target tissues. qPCR analysis of inos, cox-2 and aqps was performed. Relative protein expression of AQPs was studied by Western blot analysis. Molecular docking studies were performed to study the interaction of garcinol and hydroxycitric acid, the two important phytoconstituents of Garcinia with AQP. The qPCR analysis showed tissue-specific up-regulation of aqp1, aqp3, aqp4 and aqp8 in LPS induced rats. Garcinia extract treatment effectively lowered the mRNA expression of these AQPs. Garcinia extract significantly inhibited the LPS-induced NO, prostaglandin, cytokine and chemokine production in serum and also decreased tissue-specific transcript level of inos and cox-2, thus suggesting the anti-inflammatory role of Garcinia. Also, docking studies revealed interactions of garcinol and hydroxycitric acid with AQP1, 3, 4 and 8. Therefore, the present study suggests the possible involvement of AQP1, 3, 4 and 8 in inflammation and the efficacy of Garcinia extract as an anti-inflammatory agent. Therefore, AQPs can act as prognostic markers of inflammation and can be targeted with Garcinia extract.

Phenolic Compounds of Red Wine Aglianico del Vulture Modulate the Functional Activity of Macrophages via Inhibition of NF-κB and the Citrate Pathway

Phenolic compounds of red wine powder (RWP) extracted from the Italian red wine Aglianico del Vulture have been investigated for the potential immunomodulatory and anti-inflammatory capacity on human macrophages. These compounds reduce the secretion of IL-1β, IL-6, and TNF-α proinflammatory cytokines and increase the release of IL-10 anti-inflammatory cytokine induced by lipopolysaccharide (LPS). In addition, RWP restores Annexin A1 levels, thus involving activation of proresolutive pathways. Noteworthy, RWP lowers NF-κB protein levels, promoter activity, and nuclear translocation. As a consequence of NF-κB inhibition, reduced promoter activities of SLC25A1—encoding the mitochondrial citrate carrier (CIC)—and ATP citrate lyase (ACLY) metabolic genes have been observed. CIC, ACLY, and citrate are components of the citrate pathway: in LPS-activated macrophages, the mitochondrial citrate is exported by CIC into the cytosol where it is cleaved by ACLY in oxaloacetate and acetyl-CoA, precursors for ROS, NO^·, and PGE₂ inflammatory mediators. We identify the citrate pathway as a RWP target in carrying out its anti-inflammatory activity since RWP reduces CIC and ACLY protein levels, ACLY enzymatic activity, the cytosolic citrate concentration, and in turn ROS, NO^·, PGE₂, and histone acetylation levels. Overall findings suggest that RWP potentially restores macrophage homeostasis by suppressing inflammatory pathways and activating proresolutive processes.