Targeting ferroptosis by natural products in pathophysiological conditions.

Ferroptosis is a form of cell death that is induced by iron-mediated accumulation of lipid peroxidation. The involvement of ferroptosis in different pathophysiological conditions has offered new perspectives on potential therapeutic interventions. Natural products, which are widely recognized for their significance in drug discovery and repurposing, have shown great promise in regulating ferroptosis by targeting various ferroptosis players. In this review, we discuss the regulatory mechanisms of ferroptosis and its implications in different pathological conditions. We dissect the interactions between natural products and ferroptosis in cancer, ischemia/reperfusion, neurodegenerative diseases, acute kidney injury, liver injury, and cardiomyopathy, with an emphasis on the relevance of ferroptosis players to disease targetability.

Function and mechanism of exogenous AGR2 in colorectal cancer cells.

Background: Anterior gradient 2 (AGR2) is highly enriched in several malignant tumors and can boost tumor metastasis. Whereas, AGR2 role in colorectal cancer (CRC) is not clear. Methods: AGR2 expression in the GEPIA database was studied, and the results were confirmed by Western blot in CRC cell lines (SW480, SW620, and HT-29). The impact of AGR2 on the multiplication, migration, invasion and EMT of CRC cells were studied by CCK-8 assay, as well as clone formation, wound healing and transwell assays. The protein concent related to the AKT/ß-catenin signaling pathway were accessed via Western blot. Results: AGR2 concent in CRC tissues was notablely boosted versus normal colorectal tissues. Exogenous AGR2 boosted the multiplication of CRC cells. In addition, exogenous AGR2 induced EMT, which demonstrated that ZEB1, N-cadherin, Vimentin, Slug, Snail protein concent boosted and E-cadherin protein abated in CRC cells. In terms of mechanism, exogenous AGR2 upgulated p-AKT/AKT, p-GSK3ß/GSK3ß and ß-catenin concent. Exogenous AGR2 combined with AKT agonist IGF- Ⅰ can further enhance the multiplication, migration and invasion of CRC cells. Conclusion: Exogenous AGR2 enhances the multiplication of CRC cells and induces EMT process, the mechanism of which is related to AKT/ß-catenin signal pathway.

Itraconazole inhibits tumor growth via CEBPB-mediated glycolysis in colorectal cancer.

Advanced colorectal cancer (CRC) is characterized by a high recurrence and metastasis rate, which is the primary cause of patient mortality. Unfortunately, effective anti-cancer drugs for CRC are still lacking in clinical practice. We screened FDA-approved drugs by utilizing targeted organoid sequencing data and found that the antifungal drug itraconazole had a potential therapeutic effect on CRC tumors. However, the effect and mechanism of itraconazole on CRC tumors have not been investigated. A cell line-derived xenograft model in tumor-bearing mice was established and single-cell RNA sequencing was performed on tumor samples from four mice with or without itraconazole treatment. The proportion of cell populations and gene expression profiles was significantly different between the two groups. We found that itraconazole could inhibit tumor growth and glycolysis. We revealed that CEBPB was a new target for itraconazole, and that silencing CEBPB could repress CRC glycolysis and tumor growth by inhibiting ENO1 expression. Clinical analysis showed that CEBPB expression was obviously elevated in CRC patients, and was associated with poor survival. In summary, itraconazole treatment remodeled cell composition and gene expression profiles. Itraconazole inhibited cell glycolysis and tumor growth via the CEBPB-ENO1 axis. In this study, we illustrate a new energy metabolism mechanism for itraconazole on tumor growth in CRC that will provide a theoretical basis for CRC targeting/combination therapy.

Single-cell RNA sequencing reveals association of aberrant placental trophoblasts and FN1 reduction in late-onset fetal growth restriction.

INTRODUCTION: Fetal growth restriction (FGR) can lead to fetal mental development abnormalities, malformations, and even intrauterine death. Defects in the trophoblasts at the maternal-fetal interface may contribute to FGR. However, the impact of trophoblasts on FGR is still not well understood. Therefore, the objective of this study is to characterize the heterogeneity of placental cells at the single-cell level and investigate the role of trophoblast subtypes in the pathogenesis of FGR at the cellular and molecular levels. METHODS: Single-cell RNA sequencing was performed on the maternal side of placentas from two normal pregnant women and two pregnant women with FGR. Lentivirus transfection was used to establish a FN1 knockout model in trophoblast HTR-8-Svneo cells. The effect of FN1 knockout on cell migration and invasion of HTR-8-Svneo cells was assessed through wound healing and transwell assays. RESULTS: Nine cell types were annotated in 39,161 cells derived from single-cell RNA sequencing. The FGR group exhibited a decrease in the percentage of trophoblasts, especially in subtype of extravillous trophoblasts (EVTs). The expression of FN1 was reduced in trophoblasts and EVTs. Furthermore, the protein expression levels of FN1 in the placentas of FGR patients were significantly lower than those of normal pregnant women. The cell migration and invasion ability of HTR-8-Svneo cells were inhibited after the knockdown of FN1. DISCUSSION: The dysregulation of the trophoblast subtype-EVTs is involved in placental dysplasia related to FGR. The association between aberrant placental trophoblasts and reduced FN1 expression may contribute to insufficient remodeling of spiral arteries and the formation of FGR.

Cellular mechanism of diabetes remission by bariatric surgery.

Bariatric surgery is a powerful therapy for type 2 diabetes in patients with obesity. The mechanism of insulin sensitization by surgery has been extensively investigated in weight loss-dependent and weight loss-independent conditions. However, a consensus remains to be established regarding the underlying mechanisms. Energy deficit induced by calorie restriction (CR), that occurs both before and after surgery, represents a unique physiological basis for insulin sensitization regardless of weight loss. In support, we integrate evidence in the literature to provide an energy-based view of insulin sensitization as follows: surgery improves insulin sensitivity through the energy deficit induced by CR, leading to correction of mitochondrial overload in multiple cell types; this then triggers functional reprogramming of relevant tissues leading to diabetes remission.

Enhanced glycolysis by ATPIF1 gene inactivation increased the anti-bacterial activities of neutrophils through induction of ROS and lactic acid.

ATP synthase inhibitory factor 1 (ATPIF1) is a mitochondrial protein that regulates the activity of FoF1-ATP synthase. Mice lacking ATPIF1 throughout their bodies (Atpif1-/-) exhibit a reduction in the number of neutrophils. However, it remains unclear whether the inactivation of ATPIF1 impairs the antibacterial function of mice, this study aimed to evaluate it using a mouse peritonitis model. Mice were intraperitoneally injected with E. coli to induce peritonitis, and after 24 h, the colonies of E. coli were counted in agarose plates containing mice peritoneal lavage fluids (PLF) or extract from the liver. Neutrophils were analyzed for glucose metabolism in glycolysis following LPS stimulation. Reactive oxygen species (ROS) and lactic acid (LA) levels in neutrophils were measured using flow cytometry and Seahorse analysis, respectively. N-Acetylcysteine (NAC) and 2-Deoxy-d-glucose (2-DG) were employed to assess the role of ROS and LA in neutrophil bactericidal activity. RNA-seq analysis was conducted in neutrophils to investigate potential mechanisms. In ATPIF1-/- neutrophils, bactericidal activity was enhanced, accompanied by increased levels of ROS and LA compared to wildtype neutrophils. The augmented bactericidal activity of ATPIF1-/- neutrophils was reversed by pretreatment with NAC or 2-DG. RNA-seq analysis revealed downregulation of multiple genes involved in glutathione metabolism, pyruvate oxidation, and heme synthesis, along with increased expression of inflammatory and apoptotic genes. This study suggests that the inactivation of the Atpif1 gene enhances glucose metabolism in neutrophils, resulting in increased bactericidal activity mediated by elevated levels of ROS and LA. Inhibiting ATPIF1 may be a potential approach to enhance antibacterial immunity.

Corrigendum: Diversity and heterogeneity in human breast cancer adipose tissue revealed at single-nucleus resolution.

[This corrects the article DOI: 10.3389/fimmu.2023.1158027.].

Cadmium-containing windmill-like heteropolyoxoniobate macrocycle with high yield for catalyzing Knoevenagel condensation.

A rare cadmium-containing windmill-like heteropolyoxoniobate macrocycle has been successfully synthesized with stable 1-D cyclic cluster aggregates. The compound exhibited promising basic catalytic ability for Knoevenagel condensation with a high yield under mild reaction conditions and high cycling stability. The theoretical calculation showed that the promising basic catalytic ability is due to the dense and stronger basic sites of the surface terminal O atoms.

Three-dimensional visual technique based on CT lymphography data combined with methylene blue in endoscopic sentinel lymph node biopsy for breast cancer.

BACKGROUND: The combined application of blue dye and radioisotopes is currently the primary mapping technique used for sentinel lymph node biopsy (SLNB) in breast cancer patients. However, radiocolloid techniques have not been widely adopted, especially in developing countries, given the strict restrictions on radioactive materials. Consequently, we carried out a retrospective study to evaluate the feasibility and accuracy of three-dimensional visualization technique (3DVT) based on computed tomography-lymphography (CT-LG) in endoscopic sentinel lymph node biopsy (ESLNB) for breast cancer. METHODS: From September 2018 to June 2020, 389 patients who underwent surgical treatment of breast cancer in our department were included in this study. The CT-LG data of these patients were reconstructed into digital 3D models and imported into Smart Vision Works V1.0 to locate the sentinel lymph node (SLN) and for visual simulation surgery. ESLNB and endoscopic axillary lymph node dissection were carried out based on this new technique; the accuracy and clinical value of 3DVT in ESLNB were analyzed. RESULTS: The reconstructed 3D models clearly displayed all the structures of breast and axilla, which favors the intraoperative detection of SLNs. The identification rate of biopsied SLNs was 100% (389/389). The accuracy, sensitivity, and false-negative rate were 93.83% (365/389), 93.43% (128/137), and 6.57% (9/137), respectively. Upper limb lymphedema occurred in one patient 3 months after surgery during the 12-month follow-up period. CONCLUSIONS: Our 3DVT based on CT-LG data combined with methylene blue in ESLNB ensures a high identification rate of SLNs with low false-negative rates. It, therefore, has the potential to serve as a new method for SLN biopsy in breast cancer cases.

Parenteral Exposure of Mice to Ricin Toxin Induces Fatal Hypoglycemia by Cytokine-Mediated Suppression of Hepatic Glucose-6-Phosphatase Expression.

Ricin toxin is an agent of biodefense concern and we have been developing countermeasures for ricin threats. In doing so, we sought biomarkers of ricin toxicosis and found that in mice parenteral injection of ricin toxin causes profound hypoglycemia, in the absence of other clinical laboratory abnormalities. We now seek to identify the mechanisms underlying this hypoglycemia. Within the first hours following injection, while still normoglycemic, lymphopenia and pro-inflammatory cytokine secretion were observed, particularly tumor necrosis factor (TNF)-α. The cytokine response evolved over the next day into a complex storm of both pro- and anti-inflammatory cytokines. Evaluation of pancreatic function and histology demonstrated marked islet hypertrophy involving predominantly ß-cells, but only mildly elevated levels of insulin secretion, and diminished hepatic insulin signaling. Drops in blood glucose were observed even after destruction of ß-cells with streptozotocin. In the liver, we observed a rapid and persistent decrease in the expression of glucose-6-phosphatase (G6Pase) RNA and protein levels, accompanied by a drop in glucose-6-phosphate and increase in glycogen. TNF-α has previously been reported to suppress G6Pase expression. In humans, a genetic deficiency of G6Pase results in glycogen storage disease, type-I (GSD-1), a hallmark of which is potentially fatal hypoglycemia.

scRNA-seq reveals ATPIF1 activity in control of T cell antitumor activity.

ATP synthase inhibitory factor 1 (ATPIF1) is a mitochondrial protein with an activity in inhibition of F1Fo-ATP synthase. ATPIF1 activity remains unknown in the control of immune activity of T cells. In this study, we identified ATPIF1 activity in the induction of CD8+ T cell function in tumor models through genetic approaches. ATPIF1 gene inactivation impaired the immune activities of CD8+ T cells leading to quick tumor growth (B16 melanoma and Lewis lung cancer) in ATPIF1-KO mice. The KO T cells exhibited a reduced activity in proliferation and IFN-γ secretion with metabolic reprogramming of increased glycolysis and decreased oxidative phosphorylation (OXPHOS) after activation. T cell exhaustion was increased in the tumor infiltrating leukocytes (TILs) of KO mice as revealed by the single-cell RNA sequencing (scRNA-seq) and confirmed by flow cytometry. In contrast, ATPIF1 overexpression in T cells increased expression of IFN-γ and Granzyme B, subset of central memory T cells in CAR-T cells, and survival rate of NALM-6 tumor-bearing mice. These data demonstrate that ATPIF1 deficiency led to tumor immune deficiency through induction of T cell exhaustion. ATPIF1 overexpression enhanced the T cell tumor immunity. Therefore, ATPIF1 is a potential molecular target in the modulation of antitumor immunity of CD8+ T cells in cancer immunotherapy. Induction of ATPIF1 activity may promote CAR-T activity in cancer therapy.

The mechanisms of nucleotide actions in insulin resistance.

Insulin resistance contributes to metabolic disorders in obesity and type 2 diabetes. In mechanisms of insulin resistance, the roles of glucose, fatty acids, and amino acids have been extensively documented in literature. However, the activities of nucleotides remain to be reviewed comprehensively in the regulation of insulin sensitivity. Nucleotides are well known for their activities in biosynthesis of DNA and RNA as well as their signaling activities in the form of cAMP and cGAMP. Their activities in insulin resistance are dependent on the derivatives and corresponding receptors. ATP and NADH, derivatives of adenosine, inhibit insulin signaling inside cells by downregulation of activities of AMPK and SIRT1, respectively. ATP, ADP and AMP, the well-known energy carriers, regulate cellular responses to insulin outside cells through the purinergic receptors in cell surface. Current evidence suggests that ATP, NADH, cGAMP, and uridine are potential biomarkers of insulin resistance. However, GTP and cGMP are likely the markers of insulin sensitization. Here, studies crossing the biomedical fields are reviewed to characterize nucleotide activities in the regulation of insulin sensitivity. The knowledge brings new insights into the mechanisms of insulin resistance.

ADP Induces Blood Glucose Through Direct and Indirect Mechanisms in Promotion of Hepatic Gluconeogenesis by Elevation of NADH.

Extracellular ADP, a derivative of ATP, interacts with the purinergic receptors in the cell membrane to regulate cellular activities. This signaling pathway remains unknown in the regulation of blood glucose in vivo. We investigated the acute activity of ADP in mice through a peritoneal injection. In the lean mice, in response to the ADP treatment, the blood glucose was elevated, and pyruvate tolerance was impaired. Hepatic gluconeogenesis was enhanced with elevated expression of glucogenic genes (G6pase and Pck1) in the liver. An elevation was observed in NADH, cAMP, AMP, GMP and citrate in the liver tissue in the targeted metabolomics assay. In the primary hepatocytes, ADP activated the cAMP/PKA/CREB signaling pathway, which was blocked by the antagonist (2211) of the ADP receptor P2Y13. In the circulation, gluconeogenic hormones including glucagon and corticosterone were elevated by ADP. Insulin and thyroid hormones (T3 and T4) were not altered in the blood. In the diet-induced obese (DIO) mice, NADH was elevated in the liver tissue to match the hepatic insulin resistance. Insulin resistance was intensified by ADP for further impairment in insulin tolerance. These data suggest that ADP induced the blood glucose through direct and indirect actions in liver. One of the potential pathways involves activation of the P2Y13/cAMP/PKA/CREB signaling pathway in hepatocytes and the indirect pathway may involve induction of the gluconeogenic hormones. NADH is a signal for gluconeogenesis in the liver of both DIO mice and lean mice.

Mechanism of insulin resistance in obesity: a role of ATP.

Obesity increases the risk of type 2 diabetes through the induction of insulin resistance. The mechanism of insulin resistance has been extensively investigated for more than 60 years, but the essential pathogenic signal remains missing. Existing hypotheses include inflammation, mitochondrial dysfunction, hyperinsulinemia, hyperglucagonemia, glucotoxicity, and lipotoxicity. Drug discoveries based on these hypotheses are unsuccessful in the development of new medicines. In this review, multidisciplinary literature is integrated to evaluate ATP as a primary signal for insulin resistance. The ATP production is elevated in insulin-sensitive cells under obese conditions independent of energy demand, which we have named "mitochondrial overheating." Overheating occurs because of substrate oversupply to mitochondria, leading to extra ATP production. The ATP overproduction contributes to the systemic insulin resistance through several mechanisms, such as inhibition of AMPK, induction of mTOR, hyperinsulinemia, hyperglucagonemia, and mitochondrial dysfunction. Insulin resistance represents a feedback regulation of energy oversupply in cells to control mitochondrial overloading by substrates. Insulin resistance cuts down the substrate uptake to attenuate mitochondrial overloading. The downregulation of the mitochondrial overloading by medicines, bypass surgeries, calorie restriction, and physical exercise leads to insulin sensitization in patients. Therefore, ATP may represent the primary signal of insulin resistance in the cellular protective response to the substrate oversupply. The prevention of ATP overproduction represents a key strategy for insulin sensitization.

The 14-3-3 protein YWHAB inhibits glucagon-induced hepatic gluconeogenesis through interacting with the glucagon receptor and FOXO1.

Glucagon antagonism has been reported as a new therapeutic approach to hyperglycaemia. As the 14-3-3 protein YWHAB has been identified as a regulator of the glucagon receptor (GCGR) by affinity purification and mass spectrometry, we examined the role of YWHAB in vivo. Ywhab knockout mice display impaired blood glucose homeostasis only under pyruvate stimulation. Deletion of Ywhab in mouse primary hepatocytes (MPHs) increases hepatocyte glucose production by magnifying the effect of glucagon. Mechanistic analysis indicates that YWHAB forms a phosphorylation-dependent complex with GCGR and directly interacts with forkhead box O1 (FOXO1). Together, these results reveal the inhibitory role of YWHAB in glucagon-mediated hepatic glucose production, which may be a potential target for the control of gluconeogenesis and associated metabolic diseases.

Gene Expression-Based Predication of RNA Pseudouridine Modification in Tumor Microenvironment and Prognosis of Glioma Patients.

Aberrant expression of methyltransferases and demethylases may augment tumor initiation, proliferation and metastasis through RNA modification, such as m6A and m5C. However, activity of pseudouridine (Ψ) modification of RNA remains unknown in glioma, the most common malignant intracranial tumor. In this study, we explored the expression profiles of the Ψ synthase genes in glioma and constructed an efficient prediction model for glioma prognosis based on the CGGA and TCGA datasets. In addition, the risk-score signature was positively associated with malignancy of gliomas and the abundance of tumor-infiltrating immune cells such as macrophages M0 and regulatory T cells (Tregs), but negatively associated with the abundance of monocytes, NK cell activation and T cell CD4+ naive. In terms of mechanism, the risk-score signature was positively associated with the expression of inflammatory molecules such as S100A11 and CASP4 in glioma. Overall, this study provided evidence for the activity of RNA Ψ modification in glioma malignancy and local immunity.

Effects of inflammatory and anti-inflammatory environments on the macrophage mitochondrial function.

Mitochondrial response to inflammation is crucial in the metabolic adaptation to infection. This study aimed to explore the mitochondrial response under inflammatory and anti-inflammatory environments, with a focus on the tricarboxylic acid (TCA) cycle. Expression levels of key TCA cycle enzymes and the autophagy-related protein light chain 3b (LC3b) were determined in raw 264.7 cells treated with lipopolysaccharide (LPS) and metformin (Met). Additionally, reactive oxygen species (ROS) levels and mitochondrial membrane potential were assessed using flow cytometry. Moreover, 8-week-old C57BL/6J mice were intraperitoneally injected with LPS and Met to assess the mitochondrial response in vivo. Upon LPS stimulation, the expression of key TCA enzymes, including citrate synthase, α-ketoglutarate dehydrogenase, and isocitrate dehydrogenase 2, and the mitochondrial membrane potential decreased, whereas the levels of LC3b and ROS increased. However, treatment with Met inhibited the reduction of LPS-induced enzyme levels as well as the elevation of LC3b and ROS levels. In conclusion, the mitochondrial TCA cycle is affected by the inflammatory environment, and the LPS-induced effects can be reversed by Met treatment.

A multicenter consensus: A role of furin in the endothelial tropism in obese patients with COVID-19 infection.

Furin, a cleavage enzyme, is increasingly recognized in the pathogenesis of metabolic syndrome. Its cleavage action is an essential activation step for the endothelial pathogenicity of several viruses including SARS-CoV-2. This Furin-mediated endothelial tropism seems to underlie the multi-organ system involvement of COVID-19; which is a feature that was not recognized in the older versions of coronaviridae. Obese and diabetic patients, males, and the elderly, have increased serum levels of Furin, with its increased cellular activity; this might explain why these subgroups are at an increased risk of COVID-19 related complications and deaths. In contrast, smoking decreases cellular levels of Furin, this finding may be at the origin of the decreased severity of COVID-19 in smokers. Chinese herbal derived luteolin is suggested to be putative Furin inhibitor, with previous success against Dengue Fever. Additionally, Furin intracellular levels are largely dependent on concentration of intracellular ions, notably sodium, potassium, and magnesium. Consequently, the use of ion channel inhibitors, such as Calcium Channel blockers or Potassium Channel blockers, can prevent cellular transfection early in the course of the illness. Nicotine patches and Colchicine have also been suggested as potential therapies due to Furin mediated inhibition of COVID-19.