Fructose-1,6-bisphosphatase is a nonenzymatic safety valve that curtails AKT activation to prevent insulin hyperresponsiveness

Moonlighting functions of glucose metabolic enzymes and metabolites in cancer

Glucose metabolic enzymes and their metabolites not only provide energy and building blocks for synthesizing macromolecules but also possess non-canonical or moonlighting functions in response to extracellular and intracellular signalling. These moonlighting functions modulate various cellular activities, including gene expression, cell cycle progression, DNA repair, autophagy, senescence and apoptosis, cell proliferation, remodelling of the tumour microenvironment and immune responses. These functions integrate glucose metabolism with other essential cellular activities, driving cancer progression. Targeting these moonlighting functions could open new therapeutic avenues and lead to cancer-specific treatments.

S-Adenosylmethionine Deficit Disrupts Very Low-Density Lipoprotein Metabolism Promoting Liver Lipid Accumulation in Mice

Hepatic deletion of methionine adenosyltransferase-1a (Mat1a) in mice reduces S-adenosylmethionine (SAMe), a key methyl donor essential for many biological processes, which promotes the development and progression of metabolic dysfunction-associated steatotic liver disease (MASLD). Hyperglycemia and reduced MAT1A expression, along with low SAMe levels, are common in MASLD patients. This study explores how Mat1a-knockout (KO) hepatocytes respond to prolonged high glucose conditions, focusing on glucose metabolism and lipid accumulation. Hepatocytes from Mat1a-KO mice were incubated in high glucose conditions overnight, allowing for analysis of key metabolic intermediates and gene expression related to glycolysis, gluconeogenesis, glyceroneogenesis, phospholipid synthesis, and very low-density lipoprotein (VLDL) secretion. SAMe deficiency in Mat1a-KO hepatocytes led to reduced protein methyltransferase-1 activity, resulting in increased expression of glycolytic enzymes (glucokinase, phosphofructokinase, and pyruvate kinase) and decreased expression of gluconeogenic enzymes (phosphoenolpyruvate carboxykinase, fructose-1,6-bisphosphatase, and glucose-6-phosphatase). These alterations led to a reduction in dihydroxyacetone phosphate (DHAP), which subsequently inhibited mammalian target of rapamycine complex 1 (mTORC1) activity. This inhibition resulted in decreased phosphatidylcholine synthesis via the CDP-choline pathway and impaired VLDL secretion, ultimately causing lipid accumulation. Thus, under high glucose conditions, SAMe deficiency in hepatocytes depletes DHAP, inhibits mTORC1 activity, and promotes lipid buildup.

ChREBP mediates metabolic remodeling in FBP1-deficient liver

The deficiency of fructose-1,6-bisphosphatase 1 (FBP1), a key enzyme of gluconeogenesis, causes fatty liver. However, its underlying mechanism and physiological significance are not fully understood. Here we demonstrate that carbohydrate response element-binding protein (ChREBP) mediates lipid metabolic remodeling and promotes progressive triglyceride accumulation against metabolic injury in adult FBP1-deficient liver. Inducible liver-specific deletion of Fbp1 gene caused progressive hepatomegaly and hepatic steatosis, with a marked increase in hepatic de novo lipogenesis (DNL) as well as a decrease in plasma β-hydroxybutyrate levels. Notably, FBP1 deficiency resulted in a persistent activation of ChREBP and its target genes involved in glycolysis, lipogenesis, and fatty acid oxidation, even under fasting conditions. Furthermore, liver-specific ChREBP disruption could markedly restore the phenotypes of enhanced DNL and triglyceride accumulation in FBP1-deficient liver but exacerbated its hepatomegaly and liver injury, which was associated with remarkable energy deficit, impaired mammalian target of rapamycin (mTOR) activation, and increased oxidative stress. Furthermore, metabolomics analysis revealed a robust elevation of phosphoenolpyruvate, phosphoglycerates, phospholipids, and ceramides caused by ChREBP deletion in FBP1-deficient liver. Put together, these results suggest that overactivation of ChREBP pathway mediates liver metabolic remodeling in the absence of FBP1, which contributes to the pathogenesis of progressive hepatic steatosis and provides a protection against liver injury. Thus, our findings point to a beneficial role of ChREBP in metabolic remodeling in the context of excessive gluconeogenic intermediates.NEW & NOTEWORTHY FBP1 deficiency in adulthood causes progressive hepatic steatosis due to the overactivation of ChREBP pathway, which enhances lipid synthesis and inhibits fat oxidation. ChREBP-mediated metabolic remodeling protects against liver injury caused by energy deficit and oxidative stress in FBP1-deficient liver.

SR-A3 suppresses AKT activation to protect against MAFLD by inhibiting XIAP-mediated PTEN degradation

Scavenger receptor class A member 3 (SR-A3) is implicated in metabolic diseases; however, the relationship between SR-A3 and metabolic dysfunction-associated fatty liver disease (MAFLD) has not been documented. Here, we show that hepatic SR-A3 expression is significantly reduced in human and animal models in the context of MAFLD. Genetic inhibition of SR-A3 in hamsters elicits hyperlipidemia, hyperglycemia, insulin resistance, and hepatic steatosis under chow-diet condition, yet escalates in diet-induced MAFLD. Mechanistically, SR-A3 ablation enhances E3 ligase XIAP-mediated proteasomal ubiquitination of PTEN, leading to AKT hyperactivation. By contrast, hepatic overexpression of human SR-A3 is sufficient to attenuate metabolic disorders in WT hamsters fed a high-fat-high-cholesterol diet and ob/ob mice via suppressing the XIAP/PTEN/AKT axis. In parallel, pharmacological intervention by PTEN agonist oroxin B or lipid lowering agent ezetimibe differentially corrects MAFLD in hamsters.

Multiomics analysis of human serum and animal experiments reveals the protective mechanism of Qingre Huoxue Decoction against rheumatoid arthritis

Objective

Qingre Huoxue Decoction (QRHXD) is a traditional Chinese herbal prescription widely used in clinical practice with significant therapeutic effects on RA; however, its mechanism of action remains unclear. This study aimed to investigate the efficacy and underlying mechanisms of QRHXD in treating RA through clinical research, multiomics approaches, and animal experiments.

Methods

We conducted a 24-week clinical study in which QRHXD was the primary treatment, collecting serum samples from patients before and after treatment for integrated proteomic and metabolomic analysis to identify potential therapeutic targets. Bioinformatics analysis of differentially expressed proteins (DEPs) and differential metabolites (DMs) was performed using hierarchical clustering, volcano plots, heat maps, Gene Ontology (GO), and Kyoto Encyclopaedia of Genes and Genomes (KEGG) analysis. To validate the identified therapeutic targets, we constructed a collagen-induced arthritis (CIA) mouse model.

Results

Clinical research has shown that QRHXD can improve clinical symptoms and relevant indicators in RA patients, including the disease activity score-28 (DAS28), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), tender joint count (TJC), swollen joint count (SJC), visual analogue scale (VAS), patient-reported outcome (PRO), and health assessment questionnaire (HAQ). Proteomics and metabolomics analysis identified 83 DEPs and 54 DMs, including 46 upregulated and 37 downregulated proteins, as well as 11 upregulated and 43 downregulated metabolites. KEGG enrichment analysis revealed that DEPs are primarily associated with fatty acid degradation, ferroptosis, glycerolipid metabolism, and related pathways. The identified DMs are primarily associated with the AMPK signalling pathway, FoxO signalling pathway, glycolysis/gluconeogenesis, MTOR signalling pathway, and so on. GO enrichment analysis indicated that the DEPs were mainly associated with apoptotic mitochondrial changes, protein modification processes, fatty-acyl-CoA binding, and so on. Integrated proteomics and metabolomics analyses revealed a significant increase in fructose-1,6-biphosphatase 1 (FBP1) levels and a reduction in AMP-activated protein kinase (AMPK) levels in patients with RA. QRHXD inhibited FBP1 and activated AMPK signalling. Animal experiments validated the findings from proteomics and metabolomics analyses, demonstrating that QRHXD could also delay bone destruction and reduce inflammatory factor levels in CIA mice.

Conclusion

QRHXD may reduce the disease activity of RA, attenuate the inflammatory response, and delay bone destruction by inhibiting FBP1 and activating the AMPK signalling pathway.

Targeting FDFT1 Reduces Cholesterol and Bile Acid Production and Delays Hepatocellular Carcinoma Progression Through the HNF4A/ALDOB/AKT1 Axis

Targeting cholesterol metabolism is a novel direction for tumor therapy. Unfortunately, the current use of statins for hepatocellular carcinoma (HCC) is controversial. Herein, farnesyl-diphosphate farnesyltransferase 1 (FDFT1) is identified as a novel target for treating HCC and a potential alternative to statins. Twenty-three key genes in cholesterol biosynthesis are screened, and FDFT1 is identified via public databases (The Cancer Genome Atlas, International Cancer Genome Consortium and Gene Expression Omnibus). Clinical samples reveal that FDFT1 is highly expressed in HCC tissues, and this phenotype is strongly associated with a poor prognosis. Functionally, FDFT1 knockdown inhibits the proliferation and metastasis of HCC cells and suppresses hepatocarcinogenesis in vitro and in vivo, whereas FDFT1 overexpression promotes HCC cell proliferation and metastasis. Mechanistically, FDFT1 downregulation decreases cholesterol and bile acid levels and then increases hepatocyte nuclear factor 4 alpha (HNF4A) transcriptional activity. Experiments indicate that HNF4A combines with the promoter of aldolase B (ALDOB) and promotes the ALDOB transcription and that ALDOB combines with AKT serine/threonine kinase 1 (AKT1) and inhibits AKT1 phosphorylation. Moreover, FDFT1 knockdown combined with AKT inhibitor (AZD5363) treatment shows remarkable therapeutic potential. FDFT1 inhibition reduces cholesterol and bile acid levels to delay HCC progression through the HNF4A/ALDOB/AKT1 axis. Thus, targeting FDFT1 may be a novel potential strategy for treating HCC.

Triglyceride-glucose index and triglyceride-glucose-body mass index as prognostic factors for early stage breast cancer patients receiving neoadjuvant chemotherapy

BACKGROUND

Insulin resistance (IR) is closely associated with the risk of breast cancer. The triglyceride-glucose (TyG) index and the triglyceride-glucose-body mass index (TyG-BMI) are considered surrogate indicators of IR; however, their prognostic value in breast cancer patients has not been discussed. The purpose of this study is not only to explore whether the TyG index and the TyG-BMI can predict the chemotherapy response and long-term prognosis of breast cancer patients receiving neoadjuvant chemotherapy (NACT) but also to investigate the possible mediating mechanism and to analyze the relationship between TyG-related enzyme expression and drug resistance and prognosis.

METHODS

From November 2011 to December 2018, a total of 335 breast cancer patients referred to Harbin Medical University Cancer Hospital who received NACT and surgery were registered in this retrospective study. The TyG index and TyG-BMI before the first chemotherapy were retrospectively calculated. Tissue samples of breast cancer patients were obtained from the Cancer Genome Atlas database, and the associations between the expression levels of the FBP1 and G6PD enzymes and the clinicopathological features and prognosis of breast cancer were analyzed.

RESULTS

In receiver operating characteristic analyses, the optimal cutoff values for the TyG and TyG-BMI were determined at 8.01 and 194.91, respectively. Low levels of the TyG and TyG-BMI were not associated with pathological complete response. In multivariate analysis, high TyG was an independent prognostic factor for shorter disease-free survival (DFS; HR = 2.402, P = 0.008) and overall survival (OS; HR = 3.206, P = 0.010). After adjustments for the age group, cT stage group, and cN stage group, the dose-response relationships between TyG, TyG-BMI, and survival outcomes showed a linear correlation by restricted cubic spline analyses. Lg-transformed BMI did not significantly (P > 0.05) mediate the recurrence, metastasis, and deaths associated with TyG. The expressions of two enzymes related to TyG, FBP1 and G6PD, were higher in breast cancer tissues than in the adjacent normal tissues and were associated with the TNM stage. Survival analysis shows that patients with high expressions of FBP1 and G6PD have a shorter OS.

CONCLUSION

This study suggests that the TyG index level before NACT is an independent prognostic factor for DFS and OS and can serve as a promising biomarker to predict the long-term prognosis of breast cancer patients undergoing NACT. Moreover, the TyG index and TyG-BMI show a linear correlation with DFS and OS. The effect of the TyG index on DFS and OS is not significantly mediated by lg-transformed BMI. Besides, FBP1 and G6PD are prognostic indicators for breast cancer patients and may serve as biomarkers for the clinical diagnosis and treatment of breast cancer.

Effects of Alexandrium pacificum Exposure on Exopalaemon carinicauda: Hepatopancreas Histology, Antioxidant Enzyme Activity, and Transcriptome Analysis

Alexandrium pacificum, a dinoflagellate known for causing harmful algal blooms (HABs), has garnered significant attention due to its potential toxicity to marine ecosystems, fisheries, and human health. However, the effects of this toxin-producing alga on shrimp are not yet comprehensively understood. This study aimed to assess the hepatopancreas damage induced by A. pacificum in the economically important shrimp species E. carinicauda and to elucidate the underlying molecular mechanisms through histology, antioxidant enzyme activity, and transcriptome analysis. The shrimp were assigned to either a control group or an exposed group, with the latter involving exposure to A. pacificum at a concentration of 1.0 × 104 cells/mL for 7 days. A histological analysis subsequently revealed pathological changes in the hepatopancreas tissue of the exposed group, including lumen expansion and the separation of the basement membrane from epithelial cells, while antioxidant enzyme activity assays demonstrated that exposure to A. pacificum weakened the antioxidant defense system, as evidenced by the reduced activities of catalase, superoxide dismutase, and glutathione, along with increased malondialdehyde levels. Transcriptome analysis further identified 663 significantly upregulated genes and 1735 significantly downregulated ones in the exposed group, with these differentially expressed genes being primarily associated with pathways such as protein processing in the endoplasmic reticulum, mitophagy, glycolysis/gluconeogenesis, sphingolipid metabolism, and glycerophospholipid metabolism. This study provides novel insights into the toxicological effects of A. pacificum on aquatic organisms and enhances the current understanding of the ecotoxicological risks posed by HABs.

FBP1 controls liver cancer evolution from senescent MASH hepatocytes

Hepatocellular carcinoma (HCC) originates from differentiated hepatocytes undergoing compensatory proliferation in livers damaged by viruses or metabolic-dysfunction-associated steatohepatitis (MASH)1. While increasing HCC risk2, MASH triggers p53-dependent hepatocyte senescence3, which we found to parallel hypernutrition-induced DNA breaks. How this tumour-suppressive response is bypassed to license oncogenic mutagenesis and enable HCC evolution was previously unclear. Here we identified the gluconeogenic enzyme fructose-1,6-bisphosphatase 1 (FBP1) as a p53 target that is elevated in senescent-like MASH hepatocytes but suppressed through promoter hypermethylation and proteasomal degradation in most human HCCs. FBP1 first declines in metabolically stressed premalignant disease-associated hepatocytes and HCC progenitor cells4,5, paralleling the protumorigenic activation of AKT and NRF2. By accelerating FBP1 and p53 degradation, AKT and NRF2 enhance the proliferation and metabolic activity of previously senescent HCC progenitors. The senescence-reversing and proliferation-supportive NRF2-FBP1-AKT-p53 metabolic switch, operative in mice and humans, also enhances the accumulation of DNA-damage-induced somatic mutations needed for MASH-to-HCC progression.

Phenyllactic acid modulates the gut microbiota, enhances intestinal health, and alleviates physical frailty in aging mice

Phenyllactic acid (PLA) is a natural antibiotic-like compound derived from certain foods and probiotics. PLA levels have been associated with age-related sarcopenia and provide benefits to metabolic health when derived from probiotics. However, the specific regulatory effects of PLA in aging remain largely unexplored. In this study, aging mice were administered PLA via gavage, followed by fecal 16S rRNA sequencing, measurements of targeted metabolites, glucose metabolism monitoring, and physical performance assessments. Our results indicate that PLA administration significantly altered gut microbiota composition, increased the abundance of short-chain fatty acids (SCFAs) and succinate producing microbiota, and enhanced gut integrity in aging mice. Furthermore, PLA treatment raised fasting blood glucose levels and improved physical activity. Mechanistically, PLA intake elevated the levels of circulating SCFAs and succinate, promoting glycogen metabolic homeostasis and maintaining skeletal muscle oxidative capacity. This study provides evidence that PLA modulates the gut microbiota in aging mice, supports intestinal health, promotes glucose homeostasis, and enhances physical activity.

Cell-permeated peptide P-T3H2 inhibits malignancy on hepatocellular carcinoma through stabilizing HNF4α protein

OBJECTIVES

Hepatocyte nuclear factor 4α (HNF4α) is a key regulator of hepatocyte function and has a strong therapeutic effect on hepatocellular carcinoma (HCC) by inducing the differentiation of hepatoma cell into hepatocytes. Our previous study showed that Tribbles homolog 3 (TRIB3) directly interacts with and promotes the degradation of HNF4α in non-alcoholic fatty liver disease (NAFLD). Disrupting the TRIB3-HNF4α interaction by a cell-permeating peptide, called P-T3H2, stabilized HNF4α protein. This study aimed to assess the anti-tumor impact of P-T3H2 in HCC.

METHODS

The expression of TRIB3 and HNF4α was evaluated using western blot and immunohistochemistry (IHC). Hepatic functions and cellular senescence of HCC cells were evaluated through periodic acid-Schiff (PAS) staining, acetylated low-density lipoprotein (ac-LDL) uptake and senescence-associated β-galactosidase (SA-β-gal) activity staining, respectively. RNA-Seq analysis was performed to identify differentially expressed genes in Huh7 cells treated with P-T3H2. The impact of P-T3H2 on HCC malignancy was assessed in vitro and in vivo.

RESULTS

TRIB3 exhibited a negative correlation with HNF4α in both human and mouse HCC tissues. The administration of P-T3H2 significantly inhibited the malignancy of HCC cells. Additionally, P-T3H2 stabilized HNF4α protein and facilitated the restoration of hepatic functions and the cellular senescence in HCC cells. RNA-Seq analysis demonstrated that P-T3H2 enhanced the transcriptional activity of HNF4α in HCC. Furthermore, P-T3H2 effectively suppressed the carcinogenesis and progression of HCC in mice.

CONCLUSION

P-T3H2 suppressed HCC progression through the stabilization of HNF4α protein and may be a promising therapeutic candidate for clinical application in the treatment of HCC.

Lactobacillus reuteri TISTR 2736 alleviates type 2 diabetes in rats via the hepatic IRS1/PI3K/AKT signaling pathway by mitigating oxidative stress and inflammatory mediators

PURPOSE

This study investigated the beneficial effects of Lactobacillus reuteri TISTR 2736 on glucose homeostasis, carbohydrate metabolism, and the underlying mechanisms of its actions in type 2 diabetic (T2D) rats.

METHODS

A rat model of T2D was established by a combination of a high-fat diet and streptozotocin. The diabetic rats were treated daily with L. reuteri TISTR 2736 (2 × 108 CFU/day) for 30 days. Biochemical, histopathological, and molecular analyses were carried out to determine insulin signaling, carbohydrate metabolism, oxidative stress, and inflammation.

RESULTS

The results demonstrated that treatment with L. reuteri TISTR 2736 significantly ameliorated fasting blood glucose and glucose intolerance, and improved insulin sensitivity indices in the diabetic rats. The hepatic histopathology was improved with L. reuteri TISTR 2736 treatment, which was correlated with a reduction of hepatic lipid profiles. L. reuteri TISTR 2736 significantly reduced glycogen content, fructose 1,6-bisphosphatase activity, and phosphoenolpyruvate carboxykinase 1 protein expression, and enhanced hexokinase activity in the diabetic liver. The downregulation of IRS1 and phosphorylated IRS1Ser307 and upregulation of PI3K and phosphorylated AKTSer473 proteins in the liver were found in the L. reuteri TISTR 2736-treated diabetic group. Furthermore, it was able to suppress oxidative stress and inflammation in the diabetic rats, as demonstrated by decreased malondialdehyde and protein levels of NF-κB, IL-6 and TNF-α, but increased antioxidant enzyme activities of superoxide dismutase, catalase, and glutathione peroxidase.

CONCLUSION

By inhibiting oxidative and inflammatory stress, L. reuteri TISTR 2736 alleviated hyperglycemia and improved carbohydrate metabolism through activating IRS1/PI3K/AKT pathway in the T2D rats.

Fructose-1,6-bisphosphatase 1 dephosphorylates and inhibits TERT for tumor suppression

Telomere dysfunction is intricately linked to the aging process and stands out as a prominent cancer hallmark. Here we demonstrate that telomerase activity is differentially regulated in cancer and normal cells depending on the expression status of fructose-1,6-bisphosphatase 1 (FBP1). In FBP1-expressing cells, FBP1 directly interacts with and dephosphorylates telomerase reverse transcriptase (TERT) at Ser227. Dephosphorylated TERT fails to translocate into the nucleus, leading to the inhibition of telomerase activity, reduction in telomere lengths, enhanced senescence and suppressed tumor cell proliferation and growth in mice. Lipid nanoparticle-mediated delivery of FBP1 mRNA inhibits liver tumor growth. Additionally, FBP1 expression levels inversely correlate with TERT pSer227 levels in renal and hepatocellular carcinoma specimens and with poor prognosis of the patients. These findings demonstrate that FBP1 governs cell immortality through its protein phosphatase activity and uncover a unique telomerase regulation in tumor cells attributed to the downregulation or deficiency of FBP1 expression.

FBP1 orchestrates keratinocyte proliferation/differentiation and suppresses psoriasis through metabolic control of histone acetylation

Keratinocyte proliferation and differentiation in epidermis are well-controlled and essential for reacting to stimuli such as ultraviolet light. Imbalance between proliferation and differentiation is a characteristic feature of major human skin diseases such as psoriasis and squamous cell carcinoma. However, the effect of keratinocyte metabolism on proliferation and differentiation remains largely elusive. We show here that the gluconeogenic enzyme fructose-1,6-bisphosphatase 1 (FBP1) promotes differentiation while inhibits proliferation of keratinocyte and suppresses psoriasis development. FBP1 is identified among the most upregulated genes induced by UVB using transcriptome sequencing and is elevated especially in upper epidermis. Fbp1 heterozygous mice exhibit aberrant epidermis phenotypes with local hyperplasia and dedifferentiation. Loss of FBP1 promotes proliferation and inhibits differentiation of keratinocytes in vitro. Mechanistically, FBP1 loss facilitates glycolysis-mediated acetyl-CoA production, which increases histone H3 acetylation at lysine 9, resulting in enhanced transcription of proliferation genes. We further find that the expression of FBP1 is dramatically reduced in human psoriatic lesions and in skin of mouse imiquimod psoriasis model. Fbp1 deficiency in mice facilitates psoriasis-like skin lesions development through glycolysis and acetyl-CoA production. Collectively, our findings reveal a previously unrecognized role of FBP1 in epidermal homeostasis and provide evidence for FBP1 as a metabolic psoriasis suppressor.

Targeting hepatic ceruloplasmin mitigates nonalcoholic steatohepatitis by modulating bile acid metabolism

Nonalcoholic steatohepatitis (NASH) is a condition that progresses from nonalcoholic fatty liver disease (NAFLD) and is characterized by hepatic fat accumulation, inflammation, and fibrosis. It has the potential to develop into cirrhosis and liver cancer, and currently no effective pharmacological treatment is available. In this study, we investigate the therapeutic potential of targeting ceruloplasmin (Cp), a copper-containing protein predominantly secreted by hepatocytes, for treating NASH. Our result show that hepatic Cp is remarkedly upregulated in individuals with NASH and the mouse NASH model. Hepatocyte-specific Cp ablation effectively attenuates the onset of dietary-induced NASH by decreasing lipid accumulation, curbing inflammation, mitigating fibrosis, and ameliorating liver damage. By employing transcriptomics and metabolomics approaches, we have discovered that hepatic deletion of Cp brings about remarkable restoration of bile acid (BA) metabolism during NASH. Hepatic deletion of Cp effectively remodels BA metabolism by upregulating Cyp7a1 and Cyp8b1, which subsequently leads to enhanced BA synthesis and notable alterations in BA profiles. In conclusion, our studies elucidate the crucial involvement of Cp in NASH, highlighting its significance as a promising therapeutic target for the treatment of this disease.