Acacetin ameliorates insulin resistance in obesity mice through regulating Treg/Th17 balance via MiR-23b-3p/NEU1 Axis

Nrf2 Signaling Pathway as a Key to Treatment for Diabetic Dyslipidemia and Atherosclerosis

Diabetes mellitus (DM) is a chronic endocrine disorder that affects more than 20 million people in the United States. DM-related complications affect multiple organ systems and are a significant cause of morbidity and mortality among people with DM. Of the numerous acute and chronic complications, atherosclerosis due to diabetic dyslipidemia is a condition that can lead to many life-threatening diseases, such as stroke, coronary artery disease, and myocardial infarction. The nuclear erythroid 2-related factor 2 (Nrf2) signaling pathway is an emerging antioxidative pathway and a promising target for the treatment of DM and its complications. This review aims to explore the Nrf2 pathway's role in combating diabetic dyslipidemia. We will explore risk factors for diabetic dyslipidemia at a cellular level and aim to elucidate how the Nrf2 pathway becomes a potential therapeutic target for DM-related atherosclerosis.

White adipocyte-derived exosomal miR-23b inhibits thermogenesis by targeting Elf4 to regulate GLP-1R transcription

Promoting non-trembling thermogenesis of brown adipose tissue (BAT) and browning of white adipose tissue (WAT) helps prevent obesity. MiR-23b is highly expressed in adipose tissue-derived exosomes obtained from obese people, but the role of exosomal miR-23b in regulating thermogenesis and obesity progression remains to be further explored. Here, a mouse obesity model was established through high-fat diet (HFD), and inguinal WAT (iWAT)-derived exosomes and miR-23b antagomir were administered by intraperitoneal injection. The results showed that WAT-derived exosomal miR-23b upregulated body weight and adipocyte hypertrophy and enhanced insulin resistance. Moreover, exosomal miR-23b restrained mtDNA copy number and the expression of genes related to thermogenesis and mitochondrial biogenesis in BAT, and suppressed the expression of WAT browning-related genes under cold stimulation, indicating that exosomal miR-23b hindered non-trembling thermogenesis of BAT and WAT browning. Mechanism studies found that miR-23b targeted Elf4 to inhibit its expression. And Elf4 bound to the GLP-1R promoter region to promote GLP-1R transcription. In addition, silencing miR-23b effectively abolished the inhibitory effect of WAT-derived exosomes on thermogenic gene expression and mitochondrial respiration in adipocytes isolated from BAT and iWAT, which was reversed by GLP-1R knockdown. In conclusion, WAT-derived exosomal miR-23b suppressed thermogenesis by targeting Elf4 to regulate GLP-1R transcription, which contributed to the progression of obesity.

Acacetin inhibits activation of microglia to improve neuroinflammation after subarachnoid hemorrhage through the PERK signaling pathway mediated autophagy

PURPOSE

To explore the effect of acacetin on subarachnoid hemorrhage (SAH) and its possible mechanism.

METHODS

SAH model of rat was established, and intraperitoneally injected with three doses of acacetin. To verify the role of PERK pathway, we used the CCT020312 (PERK inhibitor) and Tunicamycin (activators of endoplasmic reticulum stress). The SAH score, neurological function score, brain edema content, and Evans blue (EB) exudate were evaluated. Western blot was used to determine the expression of inflammation-associated proteins and PERK pathway. The activation of microglia was also determined through Iba-1 detection. TEM and immunofluorescence staining of LC3B were performed to observe the autophagy degree of SAH rats after acacetin. Tunel/NeuN staining, HE and Nissl' staining were performed for neuronal damage.

RESULTS

Acacetin increased the neurological function score, reduce brain water content, Evans blue exudation and SAH scores. The microglia in cerebral cortex were activated after SAH, while acacetin could inhibit its activation, and decreased the expression of TNF-α and IL-6 proteins. The pathological staining showed the severe neuronal damage and increased neuronal apoptosis after SAH, while acacetin could improve these pathological changes. We also visualized the alleviated autophagy after acacetin. The expression of Beclin1 and ATF4 proteins were increased, but acacetin could inhibit them. Acacetin also inactivated PERK pathway, which could improve the neuronal injury and neuroinflammation after SAH, inhibit the microglia activation and the overactivated autophagy through PERK pathway.

CONCLUSION

Acacetin may alleviate neuroinflammation and neuronal damage through PERK pathway, thus having the protective effect on EBI after SAH.

Acacetin attenuates the pancreatic and hepatorenal dysfunction in type 2 diabetic rats induced by high-fat diet combined with streptozotocin

Acacetin is a natural flavonoid compound with multiple therapeutic potential in oxidative stress, inflammation, cancers, cardiovascular disease and infections. The present study aimed to detect the effect of acacetin on pancreatic and hepatorenal dysfunction in type 2 diabetic rats. The diabetic rats were induced by high-fat diet (HFD) followed by intraperitoneal injection of streptozotocin (STZ) at a dose of 45 mg/kg. Different doses of acacetin were orally administrated once a day for 8 weeks after the diabetic model was successfully established. The experimental results revealed that acacetin and acarbose displayed obvious attenuation in the levels of fasting blood glucose (FBG) and lipids compared to the untreated diabetic rats. In addition, the physiological function of liver and kidney was impaired in the persistent environment of hyperglycemia, while acacetin improved the damage of liver and kidney. Furthermore, hematoxylin-eosin (H&E) staining indicated that acacetin alleviated the pathological alterations of the pancreas, liver and kidney tissues. Besides, the increased levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-8 and malondialdehyde (MDA) were recused by acacetin treatment, while the reduction of superoxide dismutase (SOD) levels were suppressed by acacetin treatment. In conclusion, the experimental results demonstrated that acacetin improved the lipids and glucose levels, and hepatorenal antioxidant capacity, as well as ameliorated hepatorenal dysfunction in type 2 diabetic rats, and the potential mechanism might be associated with its antioxidant and anti-inflammatory activities.

Acacetin alleviates energy metabolism disorder through promoting white fat browning mediated by AC-cAMP pathway

Acacetin (ACA), a flavone isolated from Chinese traditional medical herbs, has numerous pharmacological activities. However, little is known about the roles in white fat browning and energy metabolism. In the present study, we investigated whether and how ACA would improve energy metabolism in vivo and in vitro. ACA (20 mg/kg) was intraperitoneally injected to the mice with obesity induced by HFD for 14 consecutive days (in vivo); differentiated 3T3-L1 adipocytes were treated with ACA (20 µmol/L and 40 µmol/L) for 24 h (in vitro). The metabolic profile, lipid accumulation, fat-browning and mitochondrial contents, and so on were respectively detected. The results in vivo showed that ACA significantly reduced the body weight and visceral adipose tissue weight, alleviated the energy metabolism disorder, and enhanced the browning-related protein expressions in adipose tissue of rats. Besides, the data in vitro revealed that ACA significantly reduced the lipid accumulation, induced the expressions of the browning-related proteins and cAMP-dependent protein kinase A (PKA), and increased the mitochondrium contents, especially enhanced the energy metabolism of adipocytes; however, treatment with beta-adrenergic receptor blocker (propranolol, Pro) or adenyl cyclase (AC) inhibitor (SQ22536, SQ) abrogated the ACA-mediated effects. The data demonstrate that ACA alleviates the energy metabolism disorder through the pro-browning effects mediated by the AC-cAMP pathway. The findings would provide the experimental foundation for ACA to prevent and treat obesity and related metabolism disorders.

M1 macrophages may be effective adjuvants for promoting Th‑17 differentiation in HBeAg positive hepatitis patients with ALT ≤2ULN

Hepatitis B virus (HBV) infection can activate macrophages to accelerate liver disease progression, including inflammation and fibrosis. However, the exact mechanism remains undetermined. The present study assessed the effects of macrophage polarization and the related cytokines on Th‑17 differentiation in HBeAg positive individuals with a HBV infection, and also evaluated the potential association of Th‑17 cell frequency with the severity of liver injury. A cross‑sectional study design was used to collect the clinical parameters, blood samples and liver tissue samples of patients with alanine transaminase £2x upper limit of normal and confirmed hepatitis B who underwent liver puncture in Qishan Hospital between January 2019‑December 2021. Macrophage and Th‑17 cell related factors were assayed using ELISA. The expression and quantification of cell surface antigen and intracellular markers in cells were assessed using flow cytometry. Pathological staining, including hematoxylin and eosin, reticular fiber staining and immunohistochemical staining were used to assess inflammation and fibrosis in the liver tissue. In the peripheral blood of patients with HBV infection, the number of CD14⁺ macrophages was significantly increased compared with the healthy control, especially in the hepatitis B e antigen (HBeAg) positive group. CD14⁺ macrophages were predominantly of the M1 type based on the assessment of the phenotype using flow cytometry and cytokine secretion. Furthermore, the percentage of M1 phenotype and related cytokines were positively correlated with Th‑17 differentiation. IL‑17A secreted by Th‑17 was positively correlated with the degree of liver inflammation and fibrosis, as well as with the severity of liver disease, which indicated that the differentiation of Th‑17 may be involved in the progression of liver disease. HBeAg may promote Th‑17 differentiation and IL‑17A production by M1 macrophages to accelerate the pathogenesis of liver inflammation and fibrosis in CHB patients.

The natural flavone acacetin protects against high-fat diet-induced lipid accumulation in the liver via the endoplasmic reticulum stress/ferroptosis pathway

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. To date, no medication has been approved to treat NAFLD. In this study, we evaluated the therapeutic effect of the natural flavone acacetin on high-fat diet (HFD)-induced NAFLD in mice and the underlying mechanisms. We found that acacetin (10, 20, 50 mg/kg/day) suppressed the increase in body weight, serum total cholesterol, triglycerides, low-density lipoprotein, aspartate aminotransferase, and alanine aminotransferase levels in mice fed with HFD with a dose-dependent manner. Hepatic lipid accumulation, iron overload, and lipid peroxidation were significantly alleviated by acacetin. Quantitative PCR and western blotting revealed that acacetin inhibited endoplasmic reticulum (ER) stress, ferroptosis, and expressions of lipid acid synthesis-related genes in the livers of HFD mice. Similar results were observed in HepG2 cells treated with oleic acid and lipopolysaccharide. The suppressive effects of acacetin on triglycerides and expression of lipid acid synthesis genes were abolished by ER stress and the ferroptosis activators, erastin or TU. Interestingly, the action of TU was more potent than that of erastin. Treatment with the ER stress inhibitor GSK and the ferroptosis inhibitor Fer-1 revealed that ER stress was the upstream signal of ferroptosis for hepatic lipid accumulation. These findings suggest the protective effect of acacetin against lipid accumulation via suppressing ER stress and ferroptosis and provide evidence that ER stress is an upstream signal of ferroptosis in lipid accumulation. Acacetin may be a promising candidate agent for NAFLD treatment.

Protective role of trametenolic acid B against sevoflurane-induced cognitive impairments by its different regulatory modalities of mir-329-3p in neurons and microglia

BACKGROUND

Postoperative cognitive dysfunction induced by anesthetics commonly occurs in elderly patients. This study aimed to evaluate the protective role of trametenolic acid B (TAB) in sevoflurane-induced cognitive impairments, and explore the underlying mechanisms.

METHODS

Animal and cell experiments were performed in rats, differentiated PC12 and HAPI cells by exposing to 2% sevoflurane for 5 h. Different concentration (20, 40 and 80 µg/mL) of TAB was administrated in rats and cells. The cognitive function of rats was evaluated using the Morris water maze test and fear conditioning test. The cell proliferation and apoptosis were investigated using a CCK-8 assay and the flow cytometry. Pro-inflammatory cytokines in microglia were measured using ELISA kits. A miRNA microarray assay was conducted to screen differentially expressed miRNAs by TAB in both PC12 and HAPI cells. The luciferase reporter assay and western blot assay were used to assess the E2F1/CCNA2 and NF-κB pathways.

RESULTS

TAB significantly alleviated sevoflurane-induced cognitive impairments in rats, improved PC12 cell viability, and inhibited the neuroinflammation of HAPI cells. miR-329-3p was downregulated in PC12 cells but upregulated in HAPI cells by TAB treatment, which mediated the effects of TAB on neurotoxicity and neuroinflammation. E2F1 and NF-κB P65 were two targets of miR-329-3p, and the E2F1/CCNA2 and NF-κB pathways were inhibited by miR-329-3p in PC12 and HAPI cells, respectively.

CONCLUSIONS

All the results provide evidence for the protective role of TAB against sevoflurane-induced cognitive impairments, which was achieved by alleviating neurotoxicity and neuroinflammation through differentially regulating miR-329-3p in neurons and microglia.

Mammalian Neuraminidases in Immune-Mediated Diseases: Mucins and Beyond

Mammalian neuraminidases (NEUs), also known as sialidases, are enzymes that cleave off the terminal neuraminic, or sialic, acid resides from the carbohydrate moieties of glycolipids and glycoproteins. A rapidly growing body of literature indicates that in addition to their metabolic functions, NEUs also regulate the activity of their glycoprotein targets. The simple post-translational modification of NEU protein targets-removal of the highly electronegative sialic acid-affects protein folding, alters protein interactions with their ligands, and exposes or covers proteolytic sites. Through such effects, NEUs regulate the downstream processes in which their glycoprotein targets participate. A major target of desialylation by NEUs are mucins (MUCs), and such post-translational modification contributes to regulation of disease processes. In this review, we focus on the regulatory roles of NEU-modified MUCs as coordinators of disease pathogenesis in fibrotic, inflammatory, infectious, and autoimmune diseases. Special attention is placed on the most abundant and best studied NEU1, and its recently discovered important target, mucin-1 (MUC1). The role of the NEU1 - MUC1 axis in disease pathogenesis is discussed, along with regulatory contributions from other MUCs and other pathophysiologically important NEU targets.

Adipose Tissue Immunomodulation and Treg/Th17 Imbalance in the Impaired Glucose Metabolism of Children with Obesity

In the last few decades, obesity has increased dramatically in pediatric patients. Obesity is a chronic disease correlated with systemic inflammation, characterized by the presence of CD4 and CD8 T cell infiltration and modified immune response, which contributes to the development of obesity related diseases and metabolic disorders, including impaired glucose metabolism. In particular, Treg and Th17 cells are dynamically balanced under healthy conditions, but imbalance occurs in inflammatory and pathological states, such as obesity. Some studies demonstrated that peripheral Treg and Th17 cells exhibit increased imbalance with worsening of glucose metabolic dysfunction, already in children with obesity. In this review, we considered the role of adipose tissue immunomodulation and the potential role played by Treg/T17 imbalance on the impaired glucose metabolism in pediatric obesity. In the patient care, immune monitoring could play an important role to define preventive strategies of pediatric metabolic disease treatments.