Hexokinase inhibitor 2-deoxyglucose coordinates citrullination of vimentin and apoptosis of fibroblast-like synoviocytes by inhibiting HK2 /mTORC1-induced autophagy

Glucose transporter 2‑transported glucosamine inhibits glycolysis in cancer cell lines through competition with glucose for hexokinase II

Antiproliferative effects of glucosamine, a glucose derivative with a similar structure to glucose, have been discovered, but the molecular mechanisms are not yet fully understood. Since glucosamine and glucose not only have similar structures but also are catalyzed by the same enzyme, hexokinase (HK), the present study delved into determining whether the antiproliferative effect of glucosamine involved the inhibition of glycolysis by competition with glucose. Whole‑genome screening analysis showed that a number of the gene pathways controlled by glucosamine were directly and indirectly involved in glycolysis. In vitro experiments revealed that as more glucose was added, the antiproliferative effect of glucosamine decreased. Also, it was found that glucosamine was transported into cells mainly through glucose transporter (GLUT) 2 which was responsible for the antiproliferative effects of glucosamine. In addition, the present study found that cancer cell lines with low expression level of HKII show high sensitivity to glucosamine and a HK inhibitor, 3‑bromopyruvate, enhanced the antiproliferative effect of glucosamine. Under hypoxic conditions, activated hypoxia‑inducible factor 1α (HIF‑1α) inducing glucose uptake and glycolysis hampered glucosamine‑induced cell death and HIF1A knockdown or HK inhibitors restored the antiproliferative effects of glucosamine. These findings demonstrated that glucosamine is an efficient glycolysis inhibitor and that GLUT2 and HKII play important roles as biomarkers for determining sensitivity to glucosamine. Moreover, the results suggested that the antiproliferative effect of glucosamine may be more efficient when administered in combination with other glycolytic agents or inhibitors targeting HIF‑1α.

Ermiao San attenuating rheumatoid arthritis via PI3K/AKT/mTOR signaling activate HIF-1α induced glycolysis

ETHNOPHARMACOLOGICAL RELEVANCE

As a classic formula, Ermiao San (EMS) characterized by its less medicinal flavor and strong potency had been proven to be effective and safe in the treatment of rheumatoid arthritis (RA) during clinical experience and our previous research.

AIM OF THE STUDY

The therapeutic characteristics of multi-component and multi-target of traditional Chinese medicine prompted us to further investigated the effective compounds of EMS, and evaluated its potential mechanisms in treating RA.

MATERIALS AND METHODS

Ultra-high-performance liquid chromatography high-resolution mass spectrometry (UPLC-HRMS) was used to analyze the primary absorption components of EMS in rat serum, with secondary mass spectrometry used to assist in identifying the structures of the compounds. Open field experiments, H&E staining, safranin-O-turquoise staining, ELISA, and other methods were applied to verify the alleviating effects of EMS on exercise capacity, inflammation, and cartilage damage in CIA rats. The RA-FLS model was established using TNF-α, and observed the effects of EMS on cell migration and invasion were observed through wound healing and transwell assays. In addition, immunohistochemistry and western blotting were employed to investigate the PI3K/AKT/mTOR/HIF-1α pathway both in vivo and in vitro.

RESULTS

Seventeen compounds were identified in rat serum, which were considered as active ingredients involved in the improvement of RA by EMS. Furthermore, EMS demonstrated the outstanding anti-RA ability, as evidenced by the improvement in foot swelling and arthritis scores, alleviation of pathological changes in joint tissue, inhibition of inflammatory factors, and restoration of exercise ability. In vivo data showed that EMS reduced joint injury through the PI3K/AKT/mTOR/HIF-1α signaling pathway. In vitro studies indicated that TNF-α induced the expression of Glut1 and HK2 proteins, accelerated the glycolysis rate, and promoted migration and invasion of RA-FLS cells, leading to adverse outcomes. However, EMS regulated the expression of glycolysis-related molecules, HK2 and Glut1 through the PI3K/AKT/mTOR/HIF-1α pathway, thereby inhibiting inflammation, migration, and invasion of RA-FLS cells.

CONCLUSION

The beneficial effects of EMS in CIA rats can be attributed to the inhibition of glycolysis in synovial fibroblasts via the PI3K/AKT/mTOR/HIF-1α pathway. This finding further enriches our understanding of the mechanisms by which EMS contributes to the treatment of RA.

Ginsenoside compound K decreases presentation of citrullinated peptides by regulating autophagy-induced autoantigen activation

OBJECTIVE

Citrullinated vimentin (cVIM) triggers the immune response and is the primary autoantigen of rheumatoid arthritis (RA). Ginsenoside compound K (CK), which exerts significant anti-inflammatory effects, was the objective of this study. We aimed to investigate the role and mechanism of CK in regulating presentation of citrullinated peptides.

METHODS

In RA fibroblast-like synoviocytes (RA-FLS), the expression of autoantigen cVIM, antigen presentation-related molecules, autophagy-related proteins, and autophagic flux were investigated. The effect of CK on the antigen presentation capability of FLS was also examined under conditions of autophagy induction and inhibition. Finally, Wistar rats were immunized with cVIM to evaluate the therapeutic effect of CK in an RA model.

RESULTS

In RA-FLS, CK mitigated the expression of cVIM, autophagy-associated proteins, and antigen presentation-related molecules. This regulatory effect was associated with autophagy. cVIM-immunized rats exhibited more severe arthritis and higher levels of anti-CCP antibodies than those with adjuvant- and vimentin (VIM)-induced arthritis. CK significantly alleviated arthritis inflammation in cVIM-immunized rats.

CONCLUSIONS

CK alleviates cVIM-induced arthritis symptoms, with the regulation of autophagy presenting a key cellular event involved in cVIM generation and RA-FLS antigen-presenting ability.

Tumor-targeted nano-assemblies for energy-blocking cocktail therapy in cancer

Starvation therapy aims to "starve" tumor cells by cutting off their nutritional supply. However, due to the complex and varied energy metabolism of tumors, targeting a single nutrient supply often fails to yield significant therapeutic benefits. This study proposes a tumor energy cocktail therapy that combines metformin, an oxidative phosphorylation inhibitor, with 2-deoxy-d-glucose (2-DG), a glycolysis inhibitor, to target tumor cells. To minimize the dosage of both drugs, we have developed a drug delivery strategy that prepared metformin as a nanoderivative, denoted as MA-dots. These MA-dots not only preserve the antitumor properties of metformin but also serve as a targeted delivery platform for 2-DG, ensuring its direct reach to the tumor site. Upon reaching the acidic tumor environment, the composite disintegrates, releasing 2-DG to inhibit glycolysis by targeting hexokinase 2 (HK2), the key enzyme in glycolysis, while MA-dots inhibit mitochondrial OXPHOS. This dual action significantly reduces ATP production in tumor cells, leading to apoptosis. In human lung tumor cells, the half-maximal inhibitory concentration (IC50) of 2-DG@MA-dots was significantly lower than that of either metformin or 2-DG alone, showing a nearly 100-fold and 30-fold reduction in IC50 values to 11.78 µg mL-1, from 1159 µg mL-1 and 351.20 µg mL-1, respectively. In studies with A549 tumor-bearing mice, the combination of low-dose 2-DG and metformin did not impede tumor growth, whereas 2-DG@MA-dots markedly decreased tumor volume, with the mean final tumor volume in the combination treatment group being approximately 89 times greater than that in the 2-DG@MA-dot group. STATEMENT OF SIGNIFICANCE: Metformin is a promising antitumor agent capable of modulating mitochondrial oxidative phosphorylation to inhibit cancer growth. However, its antitumor efficacy is limited when used alone due to compensatory energy mechanisms. Hence, we introduced glycolysis inhibitor 2-deoxy-d-glucose (2-DG) to inhibit an alternative tumor energy pathway. In our study, we developed a drug delivery strategy using metformin-derived nanomedicine (MA-dots) to load 2-DG. This approach enables the co-delivery of both drugs and their synergistic effect at the tumor site, disrupting both energy pathways and introducing an innovative "energy cocktail therapy".

PPARG-mediated autophagy activation alleviates inflammation in rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a systemic inflammatory autoimmune disease characterized by joint inflammation and bone damage, that not only restricts patient activity but also tends to be accompanied by a series of complications, seriously affecting patient prognosis. Peroxisome proliferator-activated receptor gamma (PPARG), a receptor that controls cellular metabolism, regulates the function of immune cells and stromal cells. Previous studies have shown that PPARG is closely related to the regulation of inflammation. However, the role of PPARG in regulating the pathological processes of RA is poorly understood.

MATERIALS AND METHODS

PPARG expression was examined in the synovial tissues and peripheral blood mononuclear cells (PBMCs) from RA patients and the paw of collagen-induced arthritis (CIA) model rats. Molecular biology experiments were designed to examine the effect of PPARG and cannabidiol (CBD) on RAW264.7 cells and CIA rats.

RESULTS

The results reveal that PPARG accelerates reactive oxygen species (ROS) clearance by promoting autophagy, thereby inhibiting ROS-mediated macrophage polarization and NLRP3 inflammasome activation. Notably, CBD may be a promising candidate for understanding the mechanism by which PPARG regulates autophagy-mediated inflammation.

CONCLUSIONS

Taken together, these findings indicate that PPARG may have a role for distinguishing between RA patients and healthy control, and for distinguishing RA activity; moreover, PPARG could be a novel pharmacological target for alleviating RA through the mediation of autophagy. CBD can act as a PPARG agonist that alleviates the inflammatory progression of RA.

Glycolysis and beyond in glucose metabolism: exploring pulmonary fibrosis at the metabolic crossroads

At present, pulmonary fibrosis (PF) is a prevalent and irreversible lung disease with limited treatment options, and idiopathic pulmonary fibrosis (IPF) is one of its most common forms. Recent research has highlighted PF as a metabolic-related disease, including dysregulated iron, mitochondria, lipid, and glucose homeostasis. Systematic reports on the regulatory roles of glucose metabolism in PF are rare. This study explores the intricate relationships and signaling pathways between glucose metabolic processes and PF, delving into how key factors involved in glucose metabolism regulate PF progression, and the interplay between them. Specifically, we examined various enzymes, such as hexokinase (HK), 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), pyruvate kinase (PK), and lactate dehydrogenase (LDH), illustrating their regulatory roles in PF. It highlights the significance of lactate, alongside the role of pyruvate dehydrogenase kinase (PDK) and glucose transporters (GLUTs) in modulating pulmonary fibrosis and glucose metabolism. Additionally, critical regulatory factors such as transforming growth factor-beta (TGF-β), interleukin-1 beta (IL-1β), and hypoxia-inducible factor 1 subunit alpha (HIF-1α) were discussed, demonstrating their impact on both PF and glucose metabolic pathways. It underscores the pivotal role of AMP-activated protein kinase (AMPK) in this interplay, drawing connections between diabetes mellitus, insulin, insulin-like growth factors, and peroxisome proliferator-activated receptor gamma (PPARγ) with PF. This study emphasizes the role of key enzymes, regulators, and glucose transporters in fibrogenesis, suggesting the potential of targeting glucose metabolism for the clinical diagnosis and treatment of PF, and proposing new promising avenues for future research and therapeutic development.

Glycolysis, a driving force of rheumatoid arthritis

Resident synoviocytes and synovial microvasculature, together with immune cells from circulation, contribute to pannus formation, the main pathological feature of rheumatoid arthritis (RA), leading to destruction of adjacent cartilage and bone. Seeds, fibroblast-like synoviocytes (FLSs), macrophages, dendritic cells (DCs), B cells, T cells and endothelial cells (ECs) seeds with high metabolic demands undergo metabolic reprogramming from oxidative phosphorylation to glycolysis in response to poor soil of RA synovium with hypoxia, nutrient deficiency and inflammatory stimuli. Glycolysis provides rapid energy supply and biosynthetic precursors to support pathogenic growth of these seeds. The metabolite lactate accumulated during this process in turn condition the soil microenvironment and affect seeds growth by modulating signalling pathways and directing lactylation modifications. This review explores in depth the survival mechanism of seeds with high metabolic demands in the poor soil of RA synovium, providing useful support for elucidating the etiology of RA. In addition, we discuss the role and major post-translational modifications of proteins and enzymes linked to glycolysis to inspire the discovery of novel anti-rheumatic targets.

Targeting glycolytic pathway in fibroblast-like synoviocytes for rheumatoid arthritis therapy: challenges and opportunities

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by hyperplastic synovium, pannus formation, immune cell infiltration, and potential articular cartilage damage. Notably, fibroblast-like synoviocytes (FLS), especially rheumatoid arthritis fibroblast-like synoviocytes (RAFLS), exhibit specific overexpression of glycolytic enzymes, resulting in heightened glycolysis. This elevated glycolysis serves to generate ATP and plays a pivotal role in immune regulation, angiogenesis, and adaptation to hypoxia. Key glycolytic enzymes, such as hexokinase 2 (HK2), phosphofructose-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), and pyruvate kinase M2 (PKM2), significantly contribute to the pathogenic behavior of RAFLS. This increased glycolysis activity is regulated by various signaling pathways.

MATERIALS AND METHODS

A comprehensive literature search was conducted to retrieve relevant studies published from January 1, 2010, to the present, focusing on RAFLS glycolysis, RA pathogenesis, glycolytic regulation pathways, and small-molecule drugs targeting glycolysis.

CONCLUSION

This review provides a thorough exploration of the pathological and physiological characteristics of three crucial glycolytic enzymes in RA. It delves into their putative regulatory mechanisms, shedding light on their significance in RAFLS. Furthermore, the review offers an up-to-date overview of emerging small-molecule candidate drugs designed to target these glycolytic enzymes and the upstream signaling pathways that regulate them. By enhancing our understanding of the pathogenic mechanisms of RA and highlighting the pivotal role of glycolytic enzymes, this study contributes to the development of innovative anti-rheumatic therapies.

Dual inhibition of glycolysis and glutaminolysis for synergistic therapy of rheumatoid arthritis

BACKGROUND

Synovial fibroblasts in rheumatoid arthritis (RAFLS) exhibit a pathological aberration of glycolysis and glutaminolysis. Henceforth, we aimed to investigate if dual inhibition of these pathways by phytobiological compound c28MS has the potential of synergistic therapy for arthritis by targeting both glucose and glutamine metabolism.

METHODS

The presence of HK2 and GLS across various cell types and associated gene expression in human synovial cells and a murine model of arthritis was evaluated by scRNA-seq. The metabolic profiling of RAFLS cells was done using H1-nuclear magnetic resonance spectroscopy under glycolytic and glutaminolytic inhibitory conditions by incubating with 3-bromopyruvate, CB839, or dual inhibitor c28MS. FLS functional analysis was conducted under similar conditions. ELISA was employed for the quantification of IL-6, CCL2, and MMP3. K/BxN sera was administered to mice to induce arthritis for in vivo arthritis experiments.

RESULTS

scRNA-seq analysis revealed that many fibroblasts expressed Hk2 along with Gls with several genes including Ptgs2, Hif1a, Timp1, Cxcl5, and Plod2 only associated with double-positive fibroblasts, suggesting that dual inhibition can be an attractive target for fibroblasts. Metabolomic and functional analysis revealed that c28MS decreased the aggressive behavior of RAFLS by targeting both upregulated glycolysis and glutaminolysis. c28MS administered in vivo significantly decreased the severity of arthritis in the K/BxN model.

CONCLUSION

Our findings imply that dual inhibition of glycolysis and glutaminolysis could be an effective approach for the treatment of RA. It also suggests that targeting more than one metabolic pathway can be a novel treatment approach in non-cancer diseases.

Effect of 2-deoxyglucose-mediated inhibition of glycolysis on migration and invasion of HTR-8/SVneo trophoblast cells

The proper invasion of trophoblasts is crucial for embryo implantation and placental development, which is helpful to establish a correct maternal-fetal relationship. Trophoblasts can produce a large amount of lactate through aerobic glycolysis during early pregnancy. Lactate creates a low pH microenvironment around the embryo to help uterine tissue decompose and promote the invasion of trophoblasts. The purpose of this study is to reveal the the potential mechanism of aerobic glycolysis regulating the invasiveness of trophoblasts by investigating the effect of 2-Deoxy-D-glucose (2-DG), a glycolysis inhibitor, on the biological function of HTR-8/SVneo trophoblast cells, the expressions of epithelial mesenchymal transformation (EMT) markers and invasion-related factors. 2-DG could inhibit the aerobic glycolysis of trophoblasts and decrease the activity of trophoblasts in a dose-dependent manner. Moreover, 2-DG inhibited the EMT of HTR-8/SVneo cells, down-regulated the expression of invasion-related factors matrix metalloproteinase 2/9 (MMP2/9) and up-regulated the expression of tissue inhibitor of matrix metalloproteinases 1/2 (TIMP1/2), thus inhibiting cell migration and invasion. This paper provides a foundation in the significance of aerobic glycolysis of trophoblasts in the process of invasion, and also provides ideas and insights for the promotion of embryo implantation.