Ursolic Acid Ameliorates Alcoholic Liver Injury through Attenuating Oxidative Stress-Mediated Ferroptosis and Modulating Gut Microbiota.

Ursolic acid (UA), a triterpenoid found in plants, has many health benefits for liver function. However, understanding how UA intervenes in alcohol-induced ferroptosis remains unclear because of the lack of research. This study explored the protective effects of UA on alcohol-induced liver injury and further elucidated its mechanism of action. Using a mouse model, acute liver injury was induced via high-dose alcohol gavage, and UA's protective effects were assessed by analyzing serum and liver indicators. The results indicated that UA has a significant protective effect against alcohol-induced liver injury in mice. UA significantly decreased serum ALT, AST, TC, and TG levels. Histopathological examination revealed that UA significantly ameliorated liver damage. UA increased ADH, ALDH, and CYP2E1 enzyme expression levels and alleviated alcohol-induced oxidative damage by regulating alcohol metabolism. Moreover, UA increased SOD and GSH-Px levels and lowered the MDA levels in the liver. Furthermore, UA regulated ACC expression by activating the LKB1/AMPK pathway, thereby inhibiting lipid synthesis and peroxidation. UA also upregulated the expression of GPX4 and SLC7A11 in the liver and exerted hepatoprotective effects by inhibiting alcohol-induced ferroptosis. Additionally, 16S rRNA amplicon sequencing showed that excessive alcohol consumption significantly affected the composition of the mouse gut microbiota, with UA intervention proving to be beneficial for improving gut microbiota imbalance. We also validated the protective effects of UA on alcohol-treated HepG2 cells at the cellular level. In summary, these results revealed that UA can alleviate alcoholic liver injury by inhibiting oxidative stress-mediated ferroptosis and regulating gut microbiota. These findings suggest that UA may serve as a functional component in the prevention of alcoholic liver disease.

Deciphering the ferroptosis pathways in dorsal root ganglia of Friedreich ataxia models. The role of LKB1/AMPK, KEAP1, and GSK3ß in the impairment of the NRF2 response.

Friedreich ataxia (FA) is a rare neurodegenerative disease caused by decreased levels of the mitochondrial protein frataxin. Frataxin has been related in iron homeostasis, energy metabolism, and oxidative stress. Ferroptosis has recently been shown to be involved in FA cellular degeneration; however, its role in dorsal root ganglion (DRG) sensory neurons, the cells that are affected the most and the earliest, is mostly unknown. In this study, we used primary cultures of frataxin-deficient DRG neurons as well as DRG from the FXNI151F mouse model to study ferroptosis and its regulatory pathways. A lack of frataxin induced upregulation of transferrin receptor 1 and decreased ferritin and mitochondrial iron accumulation, a source of oxidative stress. However, there was impaired activation of NRF2, a key transcription factor involved in the antioxidant response pathway. Decreased total and nuclear NRF2 explains the downregulation of both SLC7A11 (a member of the system Xc, which transports cystine required for glutathione synthesis) and glutathione peroxidase 4, responsible for increased lipid peroxidation, the main markers of ferroptosis. Such dysregulation could be due to the increase in KEAP1 and the activation of GSK3ß, which promote cytosolic localization and degradation of NRF2. Moreover, there was a deficiency in the LKB1/AMPK pathway, which would also impair NRF2 activity. AMPK acts as a positive regulator of NRF2 and it is activated by the upstream kinase LKB1. The levels of LKB1 were reduced when frataxin decreased, in agreement with reduced pAMPK (Thr172), the active form of AMPK. SIRT1, a known activator of LKB1, was also reduced when frataxin decreased. MT-6378, an AMPK activator, restored NRF2 levels, increased GPX4 levels and reduced lipid peroxidation. In conclusion, this study demonstrated that frataxin deficiency in DRG neurons disrupts iron homeostasis and the intricate regulation of molecular pathways affecting NRF2 activation and the cellular response to oxidative stress, leading to ferroptosis.

Knockdown of HCK promotes HREC cell viability and inner blood-retinal barrier integrity by regulating the AMPK signaling pathway.

Diabetic retinopathy (DR), a major complication of diabetes causing blindness, is characterized by retinal damage due to capillary degeneration and vascular leakage. Current treatments are not fully effective, highlighting the need for searching new therapeutic targets. Hematopoietic cell kinase (HCK), a protein involved in various diseases, has been identified as a potential biomarker in DR, but its role in disease progression requires further investigation. Here we investigated the role of HCK in DR and its potential mechanism. We found the expression of HCK increased under the stimulation of high glucose (HG) in human retinal capillary endothelial cells (HRECs). Knockdown of HCK can improve HREC cell viability and the integrity of the internal blood-retinal barrier. HCK depletion suppressed the AMPK pathway in HG-induced HRECs. In summary, HCK may be a potential target for the treatment of DR, which provides a theoretical basis for the development of new treatment strategies.

Corilagin alleviates podocyte injury in diabetic nephropathy by regulating autophagy via the SIRT1-AMPK pathway.

BACKGROUND: Diabetic nephropathy (DN) is the most frequent chronic microvascular consequence of diabetes, and podocyte injury and malfunction are closely related to the development of DN. Studies have shown that corilagin (Cor) has hepatoprotective, anti-inflammatory, antibacterial, antioxidant, anti-hypertensive, anti-diabetic, and anti-tumor activities. AIM: To explore the protective effect of Cor against podocyte injury in DN mice and the underlying mechanisms. METHODS: Streptozotocin and a high-fat diet were combined to generate DN mice models, which were then divided into either a Cor group or a DN group (n = 8 in each group). Mice in the Cor group were intraperitoneally injected with Cor (30 mg/kg/d) for 12 wk, and mice in the DN group were treated with saline. Biochemical analysis was used to measure the blood lipid profiles. Hematoxylin and eosin staining was used to detect pathological changes in kidney tissue. Immunohistochemistry and Western blotting were used to assess the protein expression of nephrin and podocin. Mouse podocyte cells (MPC5) were cultured and treated with glucose (5 mmol/L), Cor (50 µM), high glucose (HG) (30 mmol/L), and HG (30 mmol/L) plus Cor (50 µM). Real-time quantitative PCR and Western blotting were performed to examine the effects of Cor on podocyte autophagy. RESULTS: Compared with the control group, the DN mice models had increased fasting blood glucose, glycosylated hemoglobin, triglycerides, and total cholesterol, decreased nephrin and podocin expression, increased apoptosis rate, elevated inflammatory cytokines, and enhanced oxidative stress. All of the conditions mentioned above were alleviated after intervention with Cor. In addition, Cor therapy improved SIRT1 and AMPK expression (P < 0.001), inhibited reactive oxygen species and oxidative stress, and elevated autophagy in HG-induced podocytes (P < 0.01). CONCLUSION: Cor alleviates podocyte injury by regulating autophagy via the SIRT1-AMPK pathway, thereby exerting its protective impact on renal function in DN mice.

6-Phosphogluconate dehydrogenase promotes glycolysis and fatty acid synthesis by inhibiting the AMPK pathway in lung adenocarcinoma cells.

Abnormal metabolism has emerged as a prominent hallmark of cancer and plays a pivotal role in carcinogenesis and progression of lung adenocarcinoma (LUAD). In this study, single-cell sequencing revealed that the metabolic enzyme 6-phosphogluconate dehydrogenase (PGD), which is a critical regulator of the pentose phosphate pathway (PPP), is significantly upregulated in the malignant epithelial cell subpopulation during malignant progression. However, the precise functional significance of PGD in LUAD and its underlying mechanisms remain elusive. Through the integration of TCGA database analysis and LUAD tissue microarray data, it was found that PGD expression was significantly upregulated in LUAD and closely correlated with a poor prognosis in LUAD patients. Moreover, in vitro and in vivo analyses demonstrated that PGD knockout and inhibition of its activity mitigated the proliferation, migration, and invasion of LUAD cells. Mechanistically, immunoprecipitation-mass spectrometry (IP-MS) revealed for the first time that IQGAP1 is a robust novel interacting protein of PGD. PGD decreased p-AMPK levels by competitively interacting with the IQ domain of the known AMPKα binding partner IQGAP1, which promoted glycolysis and fatty acid synthesis in LUAD cells. Furthermore, we demonstrated that the combination of Physcion (a PGD-specific inhibitor) and metformin (an AMPK agonist) could inhibit tumor growth more effectively both in vivo and in vitro. Collectively, these findings suggest that PGD is a potential prognostic biomarker and therapeutic target for LUAD.

Knockdown of NFIL3 modulates the AMPK pathway to suppress excessive cell proliferation, inflammation, and migration in rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis (RA) is one autoimmune disease that badly influences the lives of humans. Nuclear factor interleukin 3 (NFIL3) has been elucidated to join into the progression of diversiform diseases. According to a recent report, NFIL3 expression levels are increased in the peripheral blood and synovial tissues of individuals with RA. However, the detailed regulatory impacts of NFIL3 and associated pathways in RA progression need more investigations. METHODS: The mRNA and protein expressions were tested through RT-qPCR and western blot. The cell proliferation was evaluated through CCK-8 and EdU assay. The cell apoptosis was measured through flow cytometry. The levels of TNF-α, IL-6, and IL-8 were assessed through ELISA. The cell migration and invasion were tested through Transwell assay. RESULTS: In this study, NFIL3 exhibited higher expression in RA fibroblast-like synoviocytes (interleukin-1ß [IL-1ß]-triggered MH7A cell model). In addition, knockdown of NFIL3 repressed the growth of IL-1ß-mediated MH7A cells. It was also demonstrated that suppressing NFIL3 resulted in reduced inflammatory reactions in IL-1ß-mediated MH7A cells. Suppression of NFIL3 alleviated cell migration and invasion in the RA cell model. Ultimately, it was demonstrated that NFIL3 retarded the AMPK/mTOR pathway. CONCLUSION: This study demonstrated that the inhibition of NFIL3 effectively controlled the AMPK/mTOR pathway, thereby suppressing the overactive proliferation, inflammation, and migration of fibroblast-like synoviocytes in human RA. This discovery implied that NFIL3 can be a serviceable biomarker for RA therapy.

The Usnic Acid Analogue 4-FPBUA Enhances the Blood-Brain Barrier Function and Induces Autophagy in Alzheimer's Disease Mouse Models.

Preclinical and clinical studies have indicated that compromised blood-brain barrier (BBB) function contributes to Alzheimer's disease (AD) pathology. BBB breakdown ranged from mild disruption of tight junctions (TJs) with increased BBB permeability to chronic integrity loss, affecting transport across the BBB, reducing brain perfusion, and triggering inflammatory responses. We recently developed a high-throughput screening (HTS) assay to identify hit compounds that enhance the function of a cell-based BBB model. The HTS screen identified (S,E)-2-acetyl-6-[3-(4'-fluorobiphenyl-4-yl)acryloyl]-3,7,9-trihydroxy-8,9b-dimethyldibenzo-[b,d]furan-1(9bH)-one (4-FPBUA), a semisynthetic analogue of naturally occurring usnic acid, which protected the in vitro model against Aß toxicity. Usnic acid is a lichen-derived secondary metabolite with a unique dibenzofuran skeleton that is commonly found in lichenized fungi of the genera Usnea. In this study, we aimed to evaluate the effect of 4-FPBUA in vitro on the cell-based BBB model function and its in vivo ability to rectify BBB function and reduce brain Aß in two AD mouse models, namely, 5xFAD and TgSwDI. Our findings demonstrated that 4-FPBUA enhanced cell-based BBB function, increased Aß transport across the monolayer, and reversed BBB breakdown in vivo by enhancing autophagy as an mTOR inhibitor. Induced autophagy was associated with a significant reduction in Aß accumulation and related pathologies and improved memory function. These results underscore the potential of 4-FPBUA as a candidate for further preclinical exploration to better understand its mechanisms of action and to optimize dosing strategies. Continued research may also elucidate additional pathways through which 4-FPBUA contributed to the amelioration of BBB dysfunction in AD. Collectively, our findings supported the development of 4-FPBUA as a therapeutic agent against AD.

Unraveling the rationale and conducting a comprehensive assessment of AdipoRon (adiponectin receptor agonist) as a candidate drug for diabetic nephropathy and cardiomyopathy prevention and intervention-a systematic review.

Type 2 diabetes mellitus (T2DM) is a widespread chronic disease characterized by persistent hyperglycemia, leading to severe complications such as diabetic cardiomyopathy and nephropathy, significantly affecting patient health and quality of life. The complex mechanisms underlying these complications include chronic inflammation, oxidative stress, and metabolic dysregulation. Diabetic cardiomyopathy, marked by structural and functional heart abnormalities, and diabetic nephropathy, characterized by progressive kidney damage, are major contributors to the increased morbidity and mortality associated with T2DM. AdipoRon, a synthetic adiponectin receptor agonist, has shown potential in preclinical studies for mimicking the beneficial effects of endogenous adiponectin, reducing inflammation and oxidative stress, and improving lipid metabolism and mitochondrial function. This systematic review evaluates the therapeutic potential of AdipoRon, focusing on its impact on diabetic cardiomyopathy and nephropathy. Through a comprehensive literature search and analysis, we highlight AdipoRon's role in ameliorating cardiovascular and renal complications in various animal models and cellular systems. The findings underscore the urgent need for translational clinical studies to validate AdipoRon's efficacy and safety in human populations, aiming to advance this promising therapeutic approach from experimental models to clinical application, potentially offering new hope for improved management of diabetic complications.

DHA-enriched phosphatidylserine alleviates bisphenol A-induced liver injury through regulating glycerophospholipid metabolism and the SIRT1-AMPK pathway.

To investigate the alleviating effect and mechanism of the docosahexaenoic acid-enriched phosphatidylserine (DHA-PS) on bisphenol A (BPA)-induced liver injury in mice, the murine liver injury model was established by gavage of BPA (5 mg/kg) or co-administration of BPA and DHA-PS (50 mg/kg or 100 mg/kg) for 6 weeks. The results showed that after administration of 100 mg/kg DHA-PS, the liver index, serum levels of AST, ALT, TC, TG, NEFA, and LDL-C in mice were significantly decreased, while HDL-C was significantly increased. The LPS, IL-6, IL-1ß, TNF-α, and MDA levels in liver tissues were effectively down-regulated, and IL-10, SOD, GSH-Px, and CAT levels were effectively up-regulated. The H&E and Oil Red O staining results showed that liver damage was notably repaired and lipid deposition was notably reduced after DHA-PS administration. Furthermore, metabolomics and immunohistochemical studies revealed that DHA-PS mainly regulates glycerophospholipid metabolism and the SIRT1-AMPK pathway to improve metabolic disorders of the liver caused by BPA. Therefore, DHA-PS could potentially alleviate BPA-induced murine liver injury through suppressing inflammation and oxidative stress, and modulating lipid metabolism disorders.

Intestinal epithelial differentiation and barrier function is promoted in vitro by a Cynara cardunculus L. leaf extract through AMPK pathway activation.

Gut epithelial barrier perturbation leads to leaky gut syndrome and permeation of substances activating immune response. Polyphenols can improve intestinal barrier function and represent candidates for preventing development of leaky gut. Herein, we evaluated in vitro the molecular mechanisms involved in the protective effects of a polyphenol-rich extract from leaves of Cynara cardunculus L. (CCLE) on intestinal barrier function and integrity on Caco-2 human epithelial cells. Treatment with CCLE from seeding until complete differentiation improved intestinal function by increasing trans-epithelial electrical resistance (TEER), reducing paracellular permeability to fluorescein, and promoting faster recovery of tight junctions (TJ) assembly in the Ca2+ switch assay. CCLE stimulated epithelial cell differentiation inducing alkaline phosphatase activity and TJ proteins. These CCLE-induced effects were attributed to activation of AMP-activated protein kinase (AMPK) pathway. Our data support the use of Cynara cardunculus L. leaves, an agricultural co-product rich in bioactive polyphenols, for the health of intestinal epithelium.