Aloin Reduces HMGB1-Mediated Septic Responses and Improves Survival in Septic Mice by Activation of the SIRT1 and PI3K/Nrf2/HO-1 Signaling Axis

HMGB1 inhibition blocks ferroptosis and oxidative stress to ameliorate sepsis-induced acute lung injury by activating the Nrf2 pathway

The proinflammatory properties of high-mobility group box protein 1 (HMGB1) in sepsis have been extensively studied. This study aimed to investigate the impact of HMGB1 on ferroptosis and its molecular mechanism in sepsis-induced acute lung injury (ALI). A septic mouse model was established using the cecal ligation and puncture method. Blocking HMGB1 resulted in improved survival rates, reduced lung injury, decreased levels of ferroptosis markers (reactive oxygen species, malondialdehyde, and Fe2+), and enhanced antioxidant enzyme activities (superoxide dismutase and catalase) in septic mice. In addition, knockdown of HMGB1 reduced cellular permeability, ferroptosis markers, and raised antioxidant enzyme levels in lipopolysaccharide (LPS)-stimulated MLE-12 cells. Silencing of HMGB1 led to elevations in the expressions of ferroptosis core-regulators in LPS-treated MLE-12 cells, such as solute carrier family 7 member 11 (SLC7A11), solute carrier family 3 member A2 (SLC3A2), and glutathione peroxidase 4. Furthermore, blocking HMGB1 did not alter ferroptosis, oxidative stress-related changes, and permeability in LPS-treated MLE-12 cells that were pretreated with ferrostatin-1 (a ferroptosis inhibitor). HMGB1 inhibition also led to elevated expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream targets, heme oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase 1 (NQO1) in LPS-treated MLE-12 cells and lung tissues from septic mice. The Nrf2-specific inhibitor ML385 reversed the effects of HMGB1 silencing on ferroptosis and cell permeability in LPS-treated MLE-12 cells. Our findings indicated that the inhibition of HMGB1 restrains ferroptosis and oxidative stress, thereby alleviating sepsis-induced ALI through the activation of Nrf2 signaling.

New opportunities and perspectives on biosynthesis and bioactivities of secondary metabolites from Aloe vera

Historically, the genus Aloe has been an indispensable part of both traditional and modern medicine. Decades of intensive research have unveiled the major bioactive secondary metabolites of this plant. Recent pandemic outbreaks have revitalized curiosity in aloe metabolites, as they have proven pharmacokinetic profiles and repurposable chemical space. However, the structural complexity of these metabolites has hindered scientific advances in the chemical synthesis of these compounds. Multi-omics research interventions have transformed aloe research by providing insights into the biosynthesis of many of these compounds, for example, aloesone, aloenin, noreugenin, aloin, saponins, and carotenoids. Here, we summarize the biological activities of major aloe secondary metabolites with a focus on their mechanism of action. We also highlight the recent advances in decoding the aloe metabolite biosynthetic pathways and enzymatic machinery linked with these pathways. Proof-of-concept studies on in vitro, whole-cell, and microbial synthesis of aloe compounds have also been briefed. Research initiatives on the structural modification of various aloe metabolites to expand their chemical space and activity are detailed. Further, the technological limitations, patent status, and prospects of aloe secondary metabolites in biomedicine have been discussed.

Research Progress on Natural Small-Molecule Compounds for the Prevention and Treatment of Sepsis

Sepsis is a serious disease with high mortality and has been a hot research topic in medical research in recent years. With the continuous reporting of in-depth research on the pathological mechanisms of sepsis, various compounds have been developed to prevent and treat sepsis. Natural small-molecule compounds play vital roles in the prevention and treatment of sepsis; for example, compounds such as resveratrol, emodin, salidroside, ginsenoside, and others can modulate signaling through the NF-κB, STAT3, STAT1, PI3K, and other pathways to relieve the inflammatory response, immunosuppression, and organ failure caused by sepsis. Here, we discuss the functions and mechanisms of natural small-molecule compounds in preventing and treating sepsis. This review will lay the theoretical foundation for discovering new natural small-molecule compounds that can potentially prevent and treat sepsis.

LncRNA GAS5 suppresses inflammatory responses by inhibiting HMGB1 release via miR-155-5p/SIRT1 axis in sepsis

Sepsis comprises a lethal immunologic response due to infection. Increasingly, evidence has demonstrated the important role of long non-coding RNA growth arrest-specific transcript 5 (GAS5) in the regulation of sepsis. Nevertheless, the mechanisms by which GAS5 participates in the progression of sepsis remain unclear. Our study demonstrated the role and underlying mechanism of GAS5 in regulating lipopolysaccharide (LPS)-induced inflammation. In this study, GAS5 expression was found to be markedly decreased in serum samples of sepsis patients and a sepsis mouse model, and was negatively related with HMGB1 expression. GAS5 overexpression inhibited cell inflammatory responses by decreasing HMGB1 release. Furthermore, GAS5 inhibited LPS-mediated hyperacetylation and the release of HMGB1 by increasing the expression of sirtuin1 (SIRT1). Additionally, upregulated GAS5 attenuated inflammatory responses in vitro and vivo, and the knockdown of a miR-155-5p mimic and SIRT1 rescued the effects of GAS5 upregulation. Mechanistically, GAS5 sponged miR-155-5p to upregulate SIRT1, thereby inhibiting HMGB1 acetylation and release. In conclusion, our findings indicate that GAS5 suppresses inflammatory responses by modulating the miR-155-5p/SIRT1/HMGB1 axis in sepsis, providing a novel therapeutic target for inflammation in sepsis.

Jujuboside B Inhibited High Mobility Group Box Protein 1-Mediated Severe Inflammatory Responses in Human Endothelial Cells and Mice

High mobility group box protein 1 (HMGB1) is a biomolecule that acts as an alerting signal of late sepsis by accelerating the production of proinflammatory cytokines, and eventually leads to various inflammation-related symptoms. When released into plasma at high concentration, it disrupts precise diagnosis and prognosis and worsens the survival of patients with systemic inflammatory conditions. Jujuboside B (JB) is a natural compound pressed from the seed of Zizyphi Spinosi Semen, which is known for its medical efficacies in treating various conditions such as hyperlipidemia, hypoxia, and platelet aggregation. Nevertheless, the medicinal activity of JB on HMGB1-involved inflammatory response in vascular cells in the human body is still ambiguous. Therefore, we hypothesized that JB could regulate the lipopolysaccharide (LPS)-induced dynamics of HMGB1 and its mediated cascade in inflammatory responses in human umbilical vein endothelial cells (HUVECs). In this experiment, JB and HMGB1 were administered in that order. In vitro and in vivo permeability, and cell viability, adhesion, and excavation of leukocytes, development of cell adhesion molecules, and lastly production of proinflammatory substances were investigated on human endothelial cells and mouse disease models to investigate the efficacy of JB in inflammatory condition. JB substantially blocked the translocation of HMGB1 from HUVECs and controlled HMGB1-induced adhesion and extravasation of the neutrophils through LPS-treated HUVECs. Moreover, JB decreased the formation of HMGB1 receptors and continually prevented HMGB1-induced proinflammatory mechanisms by blocking transcription of nuclear factor-κB and synthesis of tumor necrosis factor-α. In conclusion, JB demonstrated preventive effects against inflammatory pathologies and showed the potential to be a candidate substance for various inflammatory diseases by regulating HMGB1-mediated cellular signaling.

Plants' bioactive secondary metabolites in the management of sepsis: Recent findings on their mechanism of action

Sepsis is a severe inflammatory response to systemic infection and is a threatening cause of death in intensive care units. In recent years, a number of studies have been conducted on the protective effect of natural products against sepsis-induced organ injury. However, a comprehensive review of these studies indicating the mechanisms of action of the bioactive compounds is still lacking. In this context, this review aimed to provide an updated analysis of the mechanism of action of plants' secondary metabolites in the management of sepsis. Scopus, Science Direct, Google Scholar, and PubMed were searched from inception to July 2022. A variety of secondary metabolites were found to be effective in sepsis management including allicin, aloin, cepharanthine, chrysin, curcumin, cyanidin, gallic acid, gingerol, ginsenoside, glycyrrhizin, hesperidin, kaempferol, narciclasine, naringenin, naringin, piperine, quercetin, resveratrol, rosmarinic acid, shogaol, silymarin, sulforaphane, thymoquinone, umbelliferone, and zingerone. The protective effects exerted by these compounds can be ascribed to their antioxidant properties as well as induction of endogenous antioxidant mechanisms, and also via the downregulation of inflammatory response and reduction of biochemical and inflammatory markers of sepsis. These findings suggest that these secondary metabolites could be of potential therapeutic value in the management of sepsis, but human studies must be performed to provide strength to their potential clinical relevance in sepsis-related morbidity and mortality reduction.

The SIRT1-HMGB1 axis: Therapeutic potential to ameliorate inflammatory responses and tumor occurrence

Inflammation is a common complication of many chronic diseases. It includes inflammation of the parenchyma and vascular systems. Sirtuin 1 (SIRT1) is a nicotinamide adenine dinucleotide (NAD)-dependent histone deacetylase, which can directly participate in the suppression of inflammation. It can also regulate the activity of other proteins. Among them, high mobility group box 1 (HMGB1) signaling can be inhibited by deacetylating four lysine residues (55, 88, 90, and 177) in quiescent endothelial cells. HMGB1 is a ubiquitous nuclear protein, once translocated outside the cell, which can interact with various target cell receptors including the receptor for advanced glycation end-products (RAGE), toll-like receptor (TLR) 2, and TLR4 and stimulates the release of pro-inflammatory cyto-/chemokines. And SIRT1 has been reported to inhibit the activity of HMGB1. Both are related to the occurrence and development of inflammation and associated diseases but show an antagonistic relationship in controlling inflammation. Therefore, in this review, we introduce how this signaling axis regulates the emergence of inflammation-related responses and tumor occurrence, providing a new experimental perspective for future inflammation research. In addition, it explores diverse upstream regulators and some natural/synthetic activators of SIRT1 as a possible treatment for inflammatory responses and tumor occurrence which may encourage the development of new anti-inflammatory drugs. Meanwhile, this review also introduces the potential molecular mechanism of the SIRT1-HMGB1 pathway to improve inflammation, suggesting that SIRT1 and HMGB1 proteins may be potential targets for treating inflammation.

HMGB1 is a critical molecule in the pathogenesis of Gram-negative sepsis

Gram-negative sepsis is a severe clinical syndrome associated with significant morbidity and mortality. Lipopolysaccharide (LPS), expressed on Gram-negative bacteria, is a potent pro-inflammatory toxin that induces inflammation and coagulation via two separate receptor systems. One is Toll-like receptor 4 (TLR4), expressed on cell surfaces and in endosomes, and the other is the cytosolic receptor caspase-11 (caspases-4 and -5 in humans). Extracellular LPS binds to high mobility group box 1 (HMGB1) protein, a cytokine-like molecule. The HMGB1-LPS complex is transported via receptor for advanced glycated end products (RAGE)-endocytosis to the endolysosomal system to reach the cytosolic LPS receptor caspase-11 to induce HMGB1 release, inflammation, and coagulation that may cause multi-organ failure. The insight that LPS needs HMGB1 assistance to generate severe inflammation has led to successful therapeutic results in preclinical Gram-negative sepsis studies targeting HMGB1. However, to date, no clinical studies have been performed based on this strategy. HMGB1 is also actively released by peripheral sensory nerves and this mechanism is fundamental for the initiation and propagation of inflammation during tissue injury. Homeostasis is achieved when other neurons actively restrict the inflammatory response via monitoring by the central nervous system and the vagus nerve through the cholinergic anti-inflammatory pathway. The neuronal control in Gram-negative sepsis needs further studies since a deeper understanding of the interplay between HMGB1 and acetylcholine may have beneficial therapeutic implications. Herein, we review the synergistic overlapping mechanisms of LPS and HMGB1 and discuss future treatment opportunities in Gram-negative sepsis.

High Mobility Group Proteins in Sepsis

Sepsis, a systemic inflammatory response disease, is the most severe complication of infection and a deadly disease. High mobility group proteins (HMGs) are non-histone nuclear proteins binding nucleosomes and regulate chromosome architecture and gene transcription, which act as a potent pro-inflammatory cytokine involved in the delayed endotoxin lethality and systemic inflammatory response. HMGs increase in serum and tissues during infection, especially in sepsis. A growing number of studies have demonstrated HMGs are not only cytokines which can mediate inflammation, but also potential therapeutic targets in sepsis. To reduce sepsis-related mortality, a better understanding of HMGs is essential. In this review, we described the structure and function of HMGs, summarized the definition, epidemiology and pathophysiology of sepsis, and discussed the HMGs-related mechanisms in sepsis from the perspectives of non-coding RNAs (microRNA, long non-coding RNA, circular RNA), programmed cell death (apoptosis, necroptosis and pyroptosis), drugs and other pathophysiological aspects to provide new targets and ideas for the diagnosis and treatment of sepsis.

The potential health benefits of aloin from genus Aloe

The Aloe species is known for its medicinal and cosmetic properties. Aloin is an active ingredient found in the leaves of medicinal plants of the genus Aloe. Aloin has attracted considerable interest for its antiinflammatory, anticancer, antibacterial, and antioxidant activities. However, since its clinical application is restricted by its unclear mechanism of action, a deeper understanding of its pharmacological activity is required. This review provides an overview of current pharmacological and toxicological studies published in English from February 2000 to August 2021. Herein, we summarized the sources and potential health benefits of aloin from a clinical application perspective to guide for further studies on the sources of aloin, aimed at efficiently increasing aloin production. Importantly, the function and mechanism of action of aloin remain unclarified. In future research, it is necessary to develop new approaches for studying the pharmacological molecular mechanisms underlying the activity of this compound against various diseases.

Aloin alleviates pathological cardiac hypertrophy via modulation of the oxidative and fibrotic response

AIMS

Pathological cardiac hypertrophy is a characteristic feature in many cardiovascular diseases (CVDs). Aloin is an anthraquinone glycoside from Aloe species, and the effect of aloin on cardiac hypertrophy and associated fibrotic changes have not been elucidated. This study investigated the effect of aloin against the isoproterenol (ISO)-induced cardiac hypertrophy in rats.

MAIN METHODS

Cardiac hypertrophy experimental model was induced in rats by subcutaneous injection of ISO for 14 days. Meanwhile, the animals were administered orally with aloin at doses of 25 and 50 mg/kg/day. On the 15th day, cardiac echocardiography was performed, the heart was collected and subjected for histopathological, gene expression, and immunoblot studies. Additionally, the effect of aloin on ISO-induced hypertrophic changes in H9c2 cells was investigated.

KEY FINDINGS

Aloin markedly alleviated ISO-induced heart injury, reduced cardiac hypertrophy, improved cardiac function, and histological alterations in the heart. Mechanistically, aloin attenuated ISO-induced fibrosis via inhibition of the levels of collagen I, α-smooth muscle actin (α-SMA), fibronectin, transforming growth factor-β (TGF-β) and pSmad2/3 proteins in the heart. Aloin alleviated ISO-induced myocardial oxidative damage and up-regulated the levels of antioxidant transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) proteins. Moreover, aloin treatment attenuated ISO-induced hypertrophic changes and the generation of reactive oxygen species (ROS) in H9c2 cells in vitro.

SIGNIFICANCE

Our findings demonstrated that aloin alleviated ISO-induced cardiac hypertrophy and fibrosis via inhibiting TGF-β/pSmad2/3 signaling and restoring myocardial antioxidants, and therefore has promising therapeutic potential against cardiac hypertrophy and fibrosis.

Reproductive toxicity of polystyrene microplastics: In vivo experimental study on testicular toxicity in mice

Microplastics (MPS) are widespread in our environment and have a potential impact on the reproductive development of humans and mammals. In this study, we evaluated the effect of 5 µm polystyrene microplastics(PS-MPS) on spermatogenesis in mice. The damage by PS-MPS to epididymal sperm was studied using blood cell counts. The results showed that the number of viable epididymis sperm after PS-MPS exposure was significantly reduced. Using Duff-Quik staining, we found that the PS-MPS exposure increased the rate of sperm deformity. The testis is an important organ responsible for normal spermatogenesis. HE and TUNEL staining showed atrophy, shedding, and apoptosis of sperm cells at all levels of the testis after exposure to PS-MPS. Western blot and qPCR analysis were used to detect Nrf2/HO-1 and NF-κB. The results showed that after PS-MPS exposure, the expression of the pro-inflammatory molecule NF-κB and that of the inflammatory factors interleukin (IL)-1β and IL-6 increased significantly, whereas that of the anti-inflammatory molecule Nrf2/HO-1 decreased. These results indicate that the abnormal sperm quality in ICR mice caused by PS-MPS exposure is closely related to the Nrf2/HO-1/NF-κB pathway.

Aloin antagonizes stimulated ischemia/reperfusion-induced damage and inflammatory response in cardiomyocytes by activating the Nrf2/HO-1 defense pathway

Myocardial ischemia/reperfusion injury (I/RI) frequently incurs in acute myocardial infarction with high morbidity and mortality worldwide and is characterized with cardiomyocyte apoptosis and inflammatory response. Aloin is a major anthraquinone from Aloe species and fulfills pleiotropic protective functions in several disease models including hepatic injury. Nevertheless, the potential of aloin in MI/RI remains elusive. Intriguingly, aloin had modest cytotoxicity in H9c2 cardiomyocytes. Importantly, aloin dose-dependently ameliorated cell viability that was inhibited in response to simulated ischemia/reperfusion (SI/R) stimulation. Moreover, the enhanced apoptosis in cells under SI/R conditions were reduced after aloin treatment, concomitant with the decrease in pro-apoptotic Bax protein levels and increase in anti-apoptotic Bcl-2 protein expression. Of interest, aloin administration attenuated SI/R-induced oxidant stress by decreasing reactive oxygen species (ROS) production, lactate dehydrogenase (LDH), and malondialdehyde (MDA) release and increasing activity of anti-oxidant stress enzyme superoxide dismutase (SOD). Additionally, the elevated pro-inflammatory cytokine levels were counteracted after aloin treatment in cells under SI/R conditions, including TNF-α, IL-6, and IL-1β. Mechanically, aloin further enforced the activation of the NF-E2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling. Noticeably, blockage of this pathway by si-Nrf2 transfection blunted aloin-mediated cardioprotective efficacy against SI/R-evoked oxidative stress injury and inflammatory response. Thus, these findings corroborate that aloin may antagonize SI/R-induced cardiomyocyte injury by attenuating excessive oxidative stress and inflammation, thereby endorsing its potential as a promising therapeutic agent against myocardial infarction.

The Regulatory Role of High-Mobility Group Protein 1 in Sepsis-Related Immunity

High-mobility group box 1 (HMGB1), a prototypical damage-associated molecular pattern (DAMP) molecule, participates in multiple processes of various inflammatory diseases through binding to its corresponding receptors. In the early phase, sepsis is mainly characterized as a multi-bacterial-induced complex, excessive inflammatory response accompanied by the release of pro-inflammatory mediators, which subsequently develops into immune paralysis. A growing number of in vivo and in vitro investigations reveal that HMGB1 plays a pivotal role in the processes of inflammatory response and immunosuppression of sepsis. Therefore, HMGB1 exerts an indispensable role in the immune disorder and life-threatening inflammatory syndrome of sepsis. HMGB1 mainly mediate the release of inflammatory factors via acting on immune cells, pyroptosis pathways and phosphorylating nuclear factor-κB. Moreover HMGB1 is also associated with the process of sepsis-related immunosuppression. Neutrophil dysfunction mediated by HMGB1 is also an aspect of the immunosuppressive mechanism of sepsis. Myeloid-derived suppressor cells (MDSCs), which are also one of the important cells that play an immunosuppressive effect in sepsis, may connect with HMGB1. Thence, further understanding of HMGB1-associated pathogenesis of sepsis may assist in development of promising treatment strategies. This review mainly discusses current perspectives on the roles of HMGB1 in sepsis-related inflammation and immunosuppressive process and its related internal regulatory mechanisms.

Aloin protects mice from diet-induced non-alcoholic steatohepatitis via activation of Nrf2/HO-1 signaling

Aloin, a naturally occurring anthraquinone glycoside derived from the Aloe species, has antioxidant and anti-inflammatory activities, but its role in non-alcoholic steatohepatitis (NASH) remains unknown. This study was designed to investigate the anti-inflammatory, antioxidant, and anti-apoptotic effects of aloin and the underlying mechanisms during NASH. Wild-type or nuclear erythroid 2-related factor 2 (Nrf2) knock-out (KO) mice were fed a choline-deficient, l-amino acid-defined, high-fat (CDAAH) diet and treated with aloin (10, 20 or 40 mg per kg bw per day) by gavage for twelve weeks. Liver and blood samples were collected to evaluate liver function, protein abundance, and histopathological status. Supplementing aloin at 20 mg kg^-1 was optimal for mitigating liver damage during NASH, as evidenced by reduced alanine transaminase and aspartate aminotransferase activity in serum. Supplementation with aloin significantly reduced serum concentration or liver protein abundance of malondialdehyde, tumor necrosis factor alpha, Interleukin (IL)-1β and IL-6. Aloin treatment enhanced hepatic superoxide dismutase activity, glutathione and serum IL-10 levels in mice with NASH. Furthermore, supplementation with aloin inhibited hepatocyte apoptosis caused by Bcl-2 up-regulation and cleaved caspase-3 and Bax down-regulation. Mechanistically, by using Nrf2 KO mice, the protective effects of aloin were associated with enhanced antioxidant, anti-inflammatory and anti-apoptotic activity, all of which were mediated by Nrf2/heme oxygenase-1 (HO-1) signaling activation. Data suggested that aloin activates the Nrf2/HO-1 pathway and has protective potential against liver injury during NASH. Therefore, aloin supplementation might contribute to the prevention and treatment of NASH via activation of the Nrf2/HO-1 pathway.

microRNA-103a-3p confers protection against lipopolysaccharide-induced sepsis and consequent multiple organ dysfunction syndrome by targeting HMGB1

BACKGROUND

Sepsis and subsequent multiple organ dysfunction syndrome (MODS) have high global incidence and mortality rate, imposing tremendous health burden. microRNAs (miRNAs or miRs) are implicated in the pathogenesis of sepsis and MODS. The aim of this study is to explore the potential mechanisms of miR-103a-3p targeted high mobility group box 1 (HMGB1) involvement in the pathogenesis of sepsis complicated with multiple organ dysfunction syndrome (MODS).

METHODS

A mouse sepsis model was induced by lipopolysaccharide (LPS). Bone marrow-derived macrophages were collected and LPS was used to establish a cellular inflammation model. Targeted binding between miR-103a-3p and HMGB1 was verified by a double luciferase assay and their roles in LPS-induced sepsis were further explored using gain-of-function experiments.

RESULTS

miR-103a-3p was decreased while HMGB1 was increased in sepsis. In LPS-induced mouse sepsis models, the downregulation of HMGB1 was found to result in reductions in NO, TNF-α, IL-1β, IL-6, lung myeloperoxidase activity, pulmonary microvascular albumin leakage, serum alanine aminotransferase, aspartate aminotransferase activity, and lung and liver tissue apoptosis. Additionally, decreased HMGB1 blunted the inflammatory response and increased survival rate of modeled mice. Importantly, HMGB1 was confirmed to a target gene of miR-103a-3p. In cellular inflammation models, miR-103a-3p was found to alleviate LPS-induced sepsis and MODS in vitro by decreasing HMGB1.

CONCLUSIONS

Taken together, our results demonstrated the inhibitory role of miR-103a-3p in sepsis via inhibiting HMGB1 expression.

Inhibition of PI3K/Akt/NF-κB signaling by Aloin for ameliorating the progression of osteoarthritis: In vitro and in vivo studies

Osteoarthritis (OA) is a progressive and degenerative joint disease. Aloin is a bitter and yellow-brown-coloured compound from the Aloe plant and is allowed for use in foods as a "natural flavour". In our study, we examined the protective effects of Aloin on the inhibition of OA development as well as its underlying mechanism in both in vitro and vivo experiments. In in-vitro experiments, the protective effect of aloin on the anabolism and catabolism of the extracellular matrix (ECM) induced by IL-1 β in chondrocytes by inhibiting the expression of pro-inflammatory factors, including TNF-α (p = 0.016), IL-6 (p = 0.006), iNOS (p = 0.001) and COX-2 (p = 0.006). Mechanistically, Aloin suppressed the IL-1β-induced activation of the PI3K/Akt/NF-κB signalling pathway cascades. Moreover, molecular docking studies demonstrated that Aloin bound strongly to PI3K. In vivo, Aloin ameliorated the OA process in the destabilization of the medial meniscus (DMM) model. In summary, our findings demonstrate that Aloin ameliorates the progression of OA via the PI3K/Akt/NF-κB signalling pathways, which supports Aloin as a promising therapeutic agent for the treatment of OA.

Mariannamides A and B, new cyclic octapeptides isolated from Mariannaea elegans NBRC102301

Two new cyclic octapeptides, mariannamides A (1) and B (2), have been isolated from Mariannaea elegans NBRC102301, a Pinus densiflora-derived filamentous fungus. Their structures were elucidated to be cyclo-(l-Leu¹-l-Pro¹-l-Pro²-l-Leu²-l-Ile¹-l-Pro³-l-Val¹-l-Ile²) and cyclo-(l-Leu¹-l-Pro¹-l-Pro²-l-Leu²-l-Ile¹-l-Pro³-l-Val¹-l-Val²) based on spectroscopic data and Marfey's method. Mariannamide A (1) promoted mRNA expression of sirtuin 1 (SIRT1) in C2C12 cells, a mouse skeletal muscle myoblast cell line, and showed the antimicrobial activity against Escherichia coli and Cryptococcus neoformans.

The implication of the crosstalk of Nrf2 with NOXs, and HMGB1 in ethanol-induced gastric ulcer: Potential protective effect is afforded by Raspberry Ketone

Ethanol consumption is one of the common causative agents implicated in gastric ulcer development. Oxidative stress plays a major role in the induction and development of gastric ulceration. NADPH oxidases (NOXs) and Nuclear factor erythroid 2-related factor 2 (Nrf2) are key players in ethanol-induced ulcers. High-mobility group box 1 (HMGB1), a ubiquitous nuclear protein, mediates various inflammation functions. However, the role of HMGB1 in ethanol-induced gastric ulcer is not yet elucidated. Raspberry Ketone (RK) is a natural phenolic compound with antioxidant and anti-inflammatory properties. In the present study, absolute ethanol (7.5 ml/kg) was used to induce gastric ulceration in rats. Raspberry Ketone (RK) (50 mg/kg) was given orally one hour before the administration of absolute ethanol. Interestingly, ethanol-induced gastric ulcer was associated with Nrf2 downregulation, which was correlated with NOX-1, 2 NOX-4, and HMGB1 upregulation, and was significantly reversed by RK pre-treatment. RK pre-treatment provided 80% gastroprotection. Gastroprotective properties of RK were mediated via antioxidant, anti-inflammatory (suppression of NF-kB and tumor necrosis factor-α), and antiapoptotic activities (reduction of Bax/Bcl2 ratio). Gastroprotective properties of RK were confirmed by histopathological examination. In conclusion, this study is the first to provide evidence to the role of HMGB1 in ethanol-induced gastric ulcer, and the crosstalk of Nrf2, NOXs and HMGB1. It also demonstrates that RK represents a promising gastroprotective activity comparable to omeprazole.