Gentiopicroside alleviates cardiac inflammation and fibrosis in T2DM rats through targeting Smad3 phosphorylation

Targeting the bile acid receptor TGR5 with Gentiopicroside to activate Nrf2 antioxidant signaling and mitigate Parkinson's disease in an MPTP mouse model

INTRODUCTION

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by classical symptoms including bradykinesia, rest tremor and rigidity. Oxidative stress and mitochondrial dysfunction are recognized as pivotal factors in PD progression. Gentiopicroside (GPS), a secoiridoid derived from Gentiana manshurica Kitagawa, exhibits antioxidant and mitophagy induction properties. Nonetheless, the effects and mechanisms by which GPS mitigates neurodegeneration in PD remain to be thoroughly elucidated.

OBJECTIVES

The goal of this study was to investigate the neuroprotective effects and mechanisms of GPS in PD models.

METHODS

We established the MPTP/MPP+-induced PD models to measure the neuroprotection of GPS. Transcriptomic analysis, oxidative biochemical kits, western blot and cell immunofluorescence were conducted to elucidate the fundamental mechanisms at play. Subsequently, the targeting and activation of the transmembrane G protein-coupled receptor-5 (TGR5) by GPS were measured by molecular docking, cellular thermal shift assay, microscale thermophoresis (MST) and cyclic adenosine monophosphate (cAMP) quantitation. Finally, we verified whether the neuroprotective and antioxidant effects of GPS were dependent on TGR5 by using specific small interfering RNA (siRNA), pharmacological antagonist and knockout mice.

RESULTS

GPS significantly attenuated dopaminergic (DAergic) neuron loss and restored motor function in the MPTP-induced PD mouse model. Whole-genome RNA sequencing and subsequent mechanistic investigations revealed that GPS enhanced the expression and facilitated nuclear entry of factor erythroid-related 2-factor 2 (Nrf2), and reduced oxidative stress and mitochondrial dysfunction stimulated by neurotoxin. Additionally, GPS could target TGR5 and prevent its downregulation in PD model. TGR5's silencing or inhibition weakened the neuroprotective effect of GPS and blocked GPS-mediated activation of Nrf2 antioxidant signaling in PD model. Moreover, the therapeutic effect of GPS in mitigating motor deficits and neurodegeneration was also abolished in Tgr5 knockout mice.

CONCLUSION

These findings collectively indicated that GPS targeted TGR5 to activate Nrf2 antioxidant signaling and ultimately ameliorated the pathological progression of PD.

Crosstalk between microRNA and inflammation; critical regulator of diabetes

A growing body of evidence indicates that microRNAs (miRNAs may be used as biomarkers for the diagnosis, prognosis, and treatment of diabetes, given their changed expression profile as the disease progresses. There is growing interest in using individual miRNAs or whole miRNA clusters linked to diabetes as therapeutic targets because of their abnormal expression and functioning. In diabetes, miRNAs are also involved in inflammatory and immunological responses. Additionally, the inflammatory response controls the generation, processing, and stability of pre- or mature miRNAs and miRNA biogenesis. With a comprehensive grasp of molecular biological activities and the signaling axis, this review emphasizes the critical functions of miRNAs in inflammatory and immunological processes in diabetes. We further emphasized the potential role of these miRNAs in controlling inflammation associated with diabetes. This assessment will direct the shift from many studies to practical applications for tailored diabetes treatment and assist in identifying new therapeutic targets and approaches.

Gentiopicroside ameliorates synovial inflammation and fibrosis in KOA rats by modulating the HMGB1-mediated PI3K/AKT signaling axis

BACKGROUND

Knee osteoarthritis (KOA) is a degenerative joint disease characterized by synovial inflammation and fibrosis. Gentiopicroside (GPS), one of the main active ingredients of Gentiana macrophylla, is widely used in anti-inflammatory and anti-fibrotic therapies. However, the exact mechanism by which GPS treats synovial inflammation and fibrosis in KOA remains unclear.

METHODS

Fibroblast-like synoviocytes (FLSs) were stimulated with lipopolysaccharide (LPS) to induce inflammation and fibrosis, and CCK-8 was performed to determine the viability of GPS-treated FLSs, using immunofluorescence to examine the expression of P-PI3K and P-AKT, confocal microscopy was used to identify intracellular HMGB1 translocation. The KOA rat model was established by anterior cruciate ligament transection (ACLT) and subsequently subjected to GPS intervention. Inflammatory cytokines (TNF-α, IL-1β, and IL-6), fibrosis-related indicators (TGF-β, collagen I, TIMP1, and α-SMA), and HMGB1/PI3K/AKT signaling axis-related proteins and gene expression of fibroblast-like synoviocytes and synovial tissues were detected by Western blotting and real-time PCR. The histopathology of the synovium of the rats was assessed using Hematoxylin-eosin (HE), Sirius Red, and Masson staining. Immunohistochemistry was performed to detect the expression of HMGB1, P-PI3K, and P-AKT.

RESULTS

The present study revealed that GPS intervention significantly ameliorated inflammation and fibrosis in LPS-stimulated FLSs and KOA rat synovium. Immunofluorescence demonstrated that GPS inhibited the release of HMGB1 from the nucleus. Furthermore, GPS intervention down-regulates the levels of proteins and gene associated with the HMGB1/PI3K/AKT signaling pathway.

CONCLUSION

GPS ameliorated synovial inflammation and fibrosis in KOA rats, which may involve HMGB1-mediated activation of the PI3K/AKT signaling axis.

Application of Compounds with Anti-Cardiac Fibrosis Activity: A Review

Coronary heart disease, hypertension, myocarditis, and valvular disease cause myocardial fibrosis, leading to heart enlargement, heart failure, heart rate failure, arrhythmia, and premature ventricular beat, even defibrillation can increase the risk of sudden death. Although cardiac fibrosis is common and widespread, there are still no effective drugs to provide adequate clinical intervention for cardiac fibrosis. In this review article, we classify the compounds for treating cardiac fibrosis into natural products, synthetic compounds, and patent drugs according to their sources. Additionally, the structures, activities and signaling pathways of these compounds are discussed. This review provides insight and could provide a reference for the design of new anti-cardiac fibrosis compounds and the new use of older drugs.

Gentiopicroside Ameliorates Sepsis-Induced Acute Lung Injury via Inhibiting Inflammatory Response

Sepsis is a systemic inflammatory reaction syndrome caused by infections. Acute lung injury (ALI) occurs first and most frequently in patients with sepsis. Gentiopicroside (GPS), which originates mostly from Gentiana, is classified as a secoiridoid glycosides. Terpenoid glycosides have various biological effects, including liver protection, blood glucose and cholesterol level management, and anti-inflammatory and antitumor effects. However, presently, the biochemical foundation and mechanism of the anti-inflammatory effects of GPS in sepsis-induced ALI have not been explained. In the present study, we established a rat model of sepsis ALI induced by cecal ligation and puncture. This enables us to observe the effects of GPS therapy, which significantly reduced the inflammatory response (TNF-α, IL-1β, and IL-6), nitrogen stress, oxidative stress, and severity of ALI at both the whole animal and molecular levels. In addition, GPS ameliorates LPS-induced ALI via regulation of inflammatory response and cell proptosis in BEAS-2B. This study provides a theoretical basis for treating sepsis-induced ALI with GPS.

Gentiopicroside ameliorates glucose and lipid metabolism in T2DM via targeting FGFR1

BACKGROUND

The suppression of the fibroblast growth factor 21/fibroblast growth factor receptor 1 (FGF21/FGFR1) signaling pathway is considered as a vital factor in the type 2 diabetes mellitus (T2DM) progression. Our previous study showed that gentiopicroside (GPS), the main active compound present in Gentiana macrophylla Pall., has the capacity to control disorders related to glucose and lipid metabolism in individuals with T2DM. Nevertheless, the specific mechanism remains unclear.

PURPOSE

In light of the fact that the PharmMapper database suggests FGFR1 as the target of GPS, our investigation aims to determine if GPS can enhance glucose and lipid metabolism issues in T2DM by modulating the FGF21/FGFR1 signaling pathway.

METHODS

In this study, we used palmitic acid (PA)-induced HepG2 cells and db/db mice to investigate the function and mechanism of GPS in the FGF21/FGFR1 signaling pathway. To examine the interaction between GPS and FGFR1, researchers performed Cellular Thermal Shift Assay (CETSA) and Surface Plasmon Resonance (SPR) analysis.

RESULTS

The results suggest that GPS activates the traditional metabolic pathways, including PI3K/AKT and AMPK, which are the subsequent stages of the FGF21/FGFR1 pathway. This activation leads to the enhancement of glucose and lipid metabolism issues in PA-treated HepG2 cells and db/db mice. Furthermore, the depletion of FGFR1 has been noticed to oppose the stimulation of PI3K/AKT and AMPK pathways by GPS in HepG2 cells subjected to PA. Notability, our research affirms that GPS binds directly to FGFR1, hindering the ubiquitinated degradation of FGFR1 by neural precursor cells expressing developmentally decreased protein 4 (NEDD4) and ultimately promoting FGF21 signal transduction.

CONCLUSION

This study demonstrates that GPS targeting FGFR1 activates the PI3K/AKT and AMPK pathways, which is an important mechanism for its treatment of T2DM.

Iridoids modulate inflammation in diabetic kidney disease: A review

In recent years, preclinical research on diabetic kidney disease (DKD) has surged to the forefront of scientific and clinical attention. DKD has become a pervasive complication of type 2 diabetes. Given the complexity of its etiology and pathological mechanisms, current interventions, including drugs, dietary modifications, exercise, hypoglycemic treatments and lipid-lowering methods, often fall short in achieving desired therapeutic outcomes. Iridoids, primarily derived from the potent components of traditional herbs, have been the subject of long-standing research. Preclinical data suggest that iridoids possess notable renal protective properties; however, there has been no summary of the research on their efficacy in the management and treatment of DKD. This article consolidates findings from in vivo and in vitro research on iridoids in the context of DKD and highlights their shared anti-inflammatory activities in treating this condition. Additionally, it explores how certain iridoid components modify their chemical structures through the regulation of intestinal flora, potentially bolstering their therapeutic effects. This review provides a focused examination of the mechanisms through which iridoids may prevent or treat DKD, offering valuable insights for future research endeavors. Please cite this article as: Zhou TY, Tian N, Li L, Yu R. Iridoids modulate inflammation in diabetic kidney disease: A review. J Integr Med. 2024; 22(3): 210-222.

Gentiopicroside improves non-alcoholic steatohepatitis by activating PPARα and suppressing HIF1

Gentiopicroside (GPS) is a highly water-soluble small-molecule drug and the main bioactive secoiridoid glycoside of Gentiana scabra that has been shown to have hepatoprotective effects against non-alcoholic steatohepatitis (NASH), a form of non-alcoholic fatty liver disease (NAFLD) that can progress to cirrhosis and hepatocellular carcinoma. However, the effects of GPS on NASH and the underlying mechanisms remain obscure. Firstly, a high-fat, high-cholesterol (HFHC) diet and a high-sugar solution containing d-fructose and d-glucose were used to establish a non-alcoholic steatohepatitis (NASH) mice model. Secondly, we confirmed GPS supplementation improve metabolic abnormalities and reduce inflammation in NASH mice induced by HFHC and high-sugar solution. Then we used metabolomics to investigate the mechanisms of GPS in NASH mice. Metabolomics analysis showed GPS may work through the Peroxisome Proliferator-Activated Receptor (PPAR) signaling pathway and glycine, serine, and threonine metabolism. Functional metabolites restored by GPS included serine, glycine, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Western blot and qRT-PCR analysis confirmed GPS improve NASH by regulating PPARα and Hypoxia-Inducible Factor-1α (HIF-1α) signaling pathways. In vitro, studies further demonstrated EPA and DHA enhance fatty acid oxidation through the PPARα pathway, while serine and glycine inhibit oxidative stress through the HIF-1α pathway in palmitic acid-stimulated HepG2 cells. Our results suggest GPS's anti-inflammatory and anti-steatosis effects in NASH progression are related to the suppression of HIF-1α through the restoration of L-serine and glycine and the activation of PPARα through increased EPA and DHA.

Study of the mechanism by gentiopicroside protects against skin fibroblast glycation damage via the RAGE pathway

The occurrence of nonenzymatic glycosylation reactions in skin fibroblasts can lead to severe impairment of skin health. To investigate the protective effects of the major functional ingredient from Gentianaceae, gentiopicroside (GPS) on fibroblasts, network pharmacology was used to analyse the potential pathways and targets underlying the effects of GPS on skin. At the biochemical and cellular levels, we examined the inhibitory effect of GPS on AGEs, the regulation by GPS of key ECM proteins and vimentin, the damage caused by GPS to the mitochondrial membrane potential and the modulation by GPS of inflammatory factors such as matrix metalloproteinases (MMP-2, MMP-9), reactive oxygen species (ROS), and IL-6 via the RAGE/NF-κB pathway. The results showed that GPS can inhibit AGE-induced damage to the dermis via multiple pathways. The results of biochemical and cellular experiments showed that GPS can strongly inhibit AGE production. Conversely, GPS can block AGE-induced oxidative stress and inflammatory responses in skin cells by disrupting AGE-RAGE signalling, maintain the balance of ECM synthesis and catabolism, and alleviate AGE-induced dysfunctions in cellular behaviour. This study provides a theoretical basis for the use of GPS as an AGE inhibitor to improve skin health and alleviate the damage caused by glycosylation, showing its potential application value in the field of skin care.

Gentiopicroside inhibits retinoblastoma cell proliferation, invasion, and tumorigenesis in nude mice by suppressing the PI3K/AKT pathway

Retinoblastoma is a prevalent pediatric intraocular tumor. The suppressive effect of gentiopicroside (GPS) has been reported on various tumors. This study sought to determine the effect of GPS on retinoblastoma cell proliferation, apoptosis, invasion, and epithelial-mesenchymal transition (EMT), and tumorigenesis in nude mice. The effect and mechanism of GPS on growth, apoptosis, invasion, and EMT were determined by cell counting kit-8 (CCK-8), western blot, flow cytometry, and transwell assays in retinoblastoma cells. Y79 cells were injected into the vitreous cavity of BALB/c‑nude mice to construct a retinoblastoma mouse model. Tumor growth and mouse weight were monitored for sequential 5 weeks. The effect of GPS in vivo was assessed by immunohistochemistry (IHC), terminal deoxynucleotidyl transferase deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL), and western blot assays. GPS decreased the cell viability of both Y79 and Weri-Rb1 cells with the IC50 of 18.85 μM and 27.57 μM, respectively. Besides, GPS reduced the relative expression of proteins involved in proliferation and EMT, and the number of invading cells, while increased the apoptosis rate and the relative expressions of apoptosis proteins in retinoblastoma cells. Mechanically, GPS decreased the relative protein level of PI3K/AKT pathway, which was then recovered after 740 Y-P was applied. Correspondingly, 740 Y-P reversed the inhibitory effect of GPS on growth, invasion, and EMT, and the increased effect of GPS on apoptosis. Additionally, GPS decreased tumor volume and weight as well as the relative level of Ki-67, VEGF, p-PI3K/PI3K, and p-AKT/AKT, while increased the apoptosis rate in vivo. GPS inhibited retinoblastoma cell proliferation and invasion via deactivating the PI3K/AKT pathway in both cell and animal models.

Regulatory mechanisms of Gentiopicroside on human diseases: a brief review

Gentiopicroside (GPS), a single compound isolated from Gentiana lutea L. and the crucial representative of secoiridoid constituent, has been permitted for centuries in traditional Chinese medicine. GPS and its metabolites have been increasingly used in the search for clinical management with therapeutic properties and fewer side effects. The objective of this review was to provide a comprehensive overview of the involvement of molecular pathways in the therapeutic effects of GPS on human diseases and chronic conditions. This study presents a meticulously conducted comprehensive search of the PubMed and Google Scholar databases (from 1983 to 2023), aimed at identifying articles relating to regulatory mechanisms of GPS on human diseases and the pharmacokinetics of GPS. The inclusion criteria were meticulously and precisely defined to encompass original research papers that explicitly focused on elucidating the regulatory mechanisms of GPS in various human diseases through in vitro and animal studies. Notably, these studies were mandated to integrate specific genetic markers or pathways as essential components of their research inquiries. The evaluated pharmacokinetic parameters included maximum plasma concentration (Cmax), time to reach maximum plasma concentration (Tmax), area under the curve (AUC), clearance, and plasma half-life (t1/2). Subsequently, through a rigorous screening process of titles and abstracts, studies conducted in vitro or on animals, as well as those reporting pharmacokinetic data related to drugs other than GPS or language barriers, were systematically excluded. Drawing from the data and studies pertaining to this review, we conducted a thorough and informative analysis of the pharmacological characteristics and biological functions of GPS. These encompassed a wide range of effects, including hepatoprotective, anti-inflammatory, antifibrotic, antioxidant, analgesic, antitumor, and immunomodulatory properties. The analysis provided a comprehensive and insightful understanding of GPS's pharmacological profile and its diverse activities. Enhancing theoretical and experimental methodologies could prove advantageous in expanding the clinical applications of GPS. This could involve optimizing the bioavailability and pharmacokinetics of GPS, uncovering additional biomarkers and potential biotransformation pathways, and investigating its combined effects with standard-of-care medications.

Gentiopicroside modulates glucose homeostasis in high-fat-diet and streptozotocin-induced type 2 diabetic mice

Gluconeogenesis is closely related to the occurrence and development of type 2 diabetes mellitus (T2DM). Gentiopicroside (GPS) is the main active secoiridoid glycoside in Gentiana manshurica Kitagawa, which can improve chronic complications associated with diabetes and regulate glucose metabolism. However, the effects and potential mechanisms by which GPS affects T2DM understudied and poorly understood. In this study, we systematically explored the pharmacological effects of GPS on T2DM induced by a high-fat diet (HFD) and streptozotocin (STZ) as well as explored its related mechanisms. The results showed that GPS supplementation discernibly decreased blood glucose levels, food intake and water consumption, ameliorated glucose intolerance, abnormal pyruvate tolerance, insulin resistance and dyslipidemia. Furthermore, GPS discernibly ameliorated pathological morphological abnormalities of the liver and pancreas, reduced hepatic steatosis and maintain the balance between α-cells and β-cells in pancreas. Moreover, GPS significantly inhibited gluconeogenesis, as evidenced by the suppressed protein expression of phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6-phosphatase (G6Pase) in the liver. Additionally, the results of Western blot analysis revealed that GPS increased p-PI3K, p-AKT, and p-FOXO1 expression levels, and decreased FOXO1 expression at protein level in the liver. Furthermore, the results of the immunostaining and Western blot analysis demonstrated that GPS supplementation increased the expression of zonula occludens-1 (ZO-1) and occludin in the ileum. Collectively, these results indicate that GPS may inhibit hepatic gluconeogenesis by regulating the PI3K/AKT/FOXO1 signaling pathway and maintain intestinal barrier integrity, and ultimately improve T2DM. Together, these findings indicate that GPS is a potential candidate drug for the prevention and treatment of T2DM, and the results of our study will provide experimental basis for further exploration of the possibility of GPS as a therapeutic agent for T2DM.