Long-chain acyl-CoA synthetase 4 modulates prostaglandin E₂ release from human arterial smooth muscle cells

Multi-omics analysis reveals BPF exposure causes hepatic glucose and lipid metabolism disorder in rats by disrupting energy homeostasis

Bisphenol F (BPF) is one of the main substitutes for Bisphenol A (BPA) and is widely used in the manufacture of household products. In addition, BPF threatens human health through environmental pollution and the food chain. However, the hepatotoxicity of BPF and its effects on glucose and lipid metabolism remain unclear. This study used male SD rats as an animal model to investigate the hepatotoxicity of BPF and its effects on glucose and lipid metabolism. The results of the HE staining, serum and liver biochemical indicators show that BPF can damage the basic structure of the liver, cause liver dysfunction and lead to disorders of liver glucose metabolism and lipid metabolism. Furthermore, we conducted metabolomics and proteomics analyses on the livers of the BPF exposed group at 100 mg/kg/d in comparison with the control group. The results indicated that BPF exposure had a significant effect on liver metabolism. Combined with biological analysis and the validation of changes in genes and proteins related to glucose and lipid metabolism in the liver, it was elucidated that BPF can promote fatty acid oxidation and inhibit fatty acid synthesis through the AMPK and PPAR signaling pathways, leading to a reduction in fatty acids. Furthermore, it has been demonstrated that BPF can promote glycogen synthesis and gluconeogenesis via the AKT pathway, which can result in disorders of glucose metabolism.

Mechanism of ferroptosis in heart failure: The role of the RAGE/TLR4-JNK1/2 pathway in cardiomyocyte ferroptosis and intervention strategies

The ferroptosis of cardiomyocytes has been recognized as the core pathological mechanism of heart failure. During the evolution of cardiovascular diseases, the accumulation of angiotensin II and advanced glycation end products can lead to the excessive activation of the RAGE/TLR4-JNK1/2 pathway, which subsequently triggers ferritinophagy, clockophagy, and enhanced p53 activity, ultimately leading to cardiomyocyte ferroptosis. It is evident that deeply unraveling the specific mechanisms in this field and comprehensively evaluating potential drugs and therapeutic strategies targeting this pathway is crucial for improving the status of cardiomyocyte ferroptosis. However, our current understanding of this pathway's specific molecular biological mechanisms in the process of cardiomyocyte ferroptosis remains limited. In light of this, this paper first comprehensively reviews the historical context of ferroptosis research, compares the similarities and differences between ferroptosis and other standard modes of cell death, elucidates the core mechanisms of ferroptosis and its close connection with heart failure, aiming to establish a basic cognitive framework for readers on ferroptosis and its role in heart failure. Subsequently, the paper delves into the pivotal role of the RAGE/TLR4-JNK1/2 pathway in cardiomyocyte ferroptosis and its intricate molecular biological regulatory network. Furthermore, it systematically integrates various therapeutic approaches aimed at inhibiting RAGE, TLR4, and JNK1/2 activity to alleviate cardiomyocyte ferroptosis, encompassing RNA interference technology, gene knockout techniques, small molecule inhibitors, natural active ingredients, as well as traditional Chinese and Western medicines, with the ultimate goal of forging new avenues and strategies for the prevention and treatment of heart failure.

Long-chain fatty acyl CoA synthetase 4 expression in pancreatic cancer: a marker for malignant lesions and prognostic indicator for recurrence

BACKGROUND

Long-chain fatty acyl CoA synthetase 4 (ACSL4) is crucial for lipid metabolism, primarily catalyzing the formation of 12-20 carbon chain fatty acids. ACSL4 is upregulated in various cancers and linked to aggressive behavior and poor survival. A bioinformatics study showing ACSL4 upregulation in pancreatic cancer. However, utility for actual pathological diagnosis and clinical significance in pancreatic ductal adenocarcinoma (PDAC) and intraductal papillary mucinous neoplasm (IPMN) are unexplored. This study aimed to investigate ACSL4 expression in PDAC and IPMN, and evaluate its clinical implications.

METHODS

We examined ACSL4 expression using immunohistochemistry in 165 patients with PDAC and IPMN. Differences in ACSL4 expression between malignant and benign lesions were evaluated using the Pearson χ2 test. The association between ACSL4 expression, pathological parameters, and survival was assessed through Kaplan-Meier and Cox regression analyses in 96 patients with invasive cancer.

RESULTS

Compared to normal pancreatic ducts, low-grade pancreatic intraepithelial neoplasm, and intraductal papillary mucinous adenoma (IPMA) (3.3%, 3.4%, and 2.7%, respectively), ACSL4 expression was significantly higher in invasive PDAC, noninvasive intraductal papillary mucinous carcinoma (IPMC), and invasive IPMC (77%, 86.7%, and 93.9%, respectively). In invasive cancers, low ACSL4 expression was associated with a higher frequency of lymphovascular invasion and recurrence and shorter disease-free survival (P = 0.006). Additionally, low ACSL4 expression was an independent prognostic factor for shorter disease-free survival in multivariable Cox regression analysis (HR = 2.409, 95% CI: 1.121-5.180, P = 0.024).

CONCLUSION

ACSL4 expression helps differentiate cancerous from precancerous lesions in pancreatic cancer, but low expression is linked to a higher frequency of lymphovascular invasion and shorter disease-free survival in invasive cases. Due to the limited sample size and broad confidence intervals, the findings of this study should be interpreted with caution and require validation in larger, independent cohorts.

Natural products and ferroptosis: A novel approach for heart failure management

BACKGROUND

The discovery of ferroptosis has brought a revolutionary breakthrough in heart failure treatment, and natural products, as a significant source of drug discovery, are gradually demonstrating their extraordinary potential in regulating ferroptosis and alleviating heart failure symptoms. In addition to chemically synthesized small molecule compounds, natural products have attracted attention as an important source for discovering compounds that target ferroptosis in treating heart failure.

PURPOSE

Systematically summarize and analyze the research progress on improving heart failure through natural products' modulation of the ferroptosis pathway.

METHODS

By comprehensively searching authoritative databases like PubMed, Web of Science, and China National Knowledge Infrastructure with keywords such as "heart failure", "cardiovascular disease", "heart disease", "ferroptosis", "natural products", "active compounds", "traditional Chinese medicine formulas", "traditional Chinese medicine", and "acupuncture", we aim to systematically review the mechanism of ferroptosis and its link with heart failure. We also want to explore natural small-molecule compounds, traditional Chinese medicine formulas, and acupuncture therapies that can inhibit ferroptosis to improve heart failure.

RESULTS

In this review, we not only trace the evolution of the concept of ferroptosis and clearly distinguish it from other forms of cell death but also establish a comprehensive theoretical framework encompassing core mechanisms such as iron overload and system xc-/GSH/GPX4 imbalance, along with multiple auxiliary pathways. On this basis, we innovatively link ferroptosis with various types of heart failure, covering classic heart failure types and extending our research to pre-heart failure conditions such as arrhythmia and aortic aneurysm, providing new insights for early intervention in heart failure. Importantly, this article systematically integrates multiple strategies of natural products for interfering with ferroptosis, ranging from monomeric compounds and bioactive components to crude extracts and further to traditional Chinese medicine formulae. In addition, non-pharmacological means such as acupuncture are also included.

CONCLUSION

This study fills the gap in the systematic description of the relationship between ferroptosis and heart failure and the therapeutic strategies of natural products, aiming to provide patients with more diverse treatment options and promote the development of the heart failure treatment field.

Ferroptosis as a molecular target of epigallocatechin gallate in diseases

CONTEXT

Ferroptosis is a novel form of cell death characterised by iron overload and lipid peroxidation. It is closely associated with many diseases, including cardiovascular diseases, tumours, and neurological diseases. The use of natural chemicals to modulate ferroptosis is of great concern because of the critical role ferroptosis plays in disease. The main active ingredient in green tea is epigallocatechin gallate (EGCG), which is the most abundant catechin in green tea. EGCG shows a wide range of biological and therapeutic effects in various diseases, including anti-inflammatory, antioxidant, anticancer, and cardioprotective.

OBJECTIVE

The purpose of this article is to summarise the existing information on the relationship between EGCG and ferroptosis.

METHODS

Articles related to EGCG and ferroptosis were searched in PubMed and Web of Science databases, and the literature was analysed.

RESULTS AND CONCLUSION

EGCG could improve ferroptosis-related diseases and affect the development of ferroptosis by regulating the nuclear factor erythroid 2-related factor 2, autophagy, microRNA, signal transducer and activator of transcription 1, and protein kinase D1 signalling pathways.

Iron homeostasis and ferroptosis in muscle diseases and disorders: mechanisms and therapeutic prospects

The muscular system plays a critical role in the human body by governing skeletal movement, cardiovascular function, and the activities of digestive organs. Additionally, muscle tissues serve an endocrine function by secreting myogenic cytokines, thereby regulating metabolism throughout the entire body. Maintaining muscle function requires iron homeostasis. Recent studies suggest that disruptions in iron metabolism and ferroptosis, a form of iron-dependent cell death, are essential contributors to the progression of a wide range of muscle diseases and disorders, including sarcopenia, cardiomyopathy, and amyotrophic lateral sclerosis. Thus, a comprehensive overview of the mechanisms regulating iron metabolism and ferroptosis in these conditions is crucial for identifying potential therapeutic targets and developing new strategies for disease treatment and/or prevention. This review aims to summarize recent advances in understanding the molecular mechanisms underlying ferroptosis in the context of muscle injury, as well as associated muscle diseases and disorders. Moreover, we discuss potential targets within the ferroptosis pathway and possible strategies for managing muscle disorders. Finally, we shed new light on current limitations and future prospects for therapeutic interventions targeting ferroptosis.

The Octadecanoids: Synthesis and Bioactivity of 18-Carbon Oxygenated Fatty Acids in Mammals, Bacteria, and Fungi

The octadecanoids are a broad class of lipids consisting of the oxygenated products of 18-carbon fatty acids. Originally referring to production of the phytohormone jasmonic acid, the octadecanoid pathway has been expanded to include products of all 18-carbon fatty acids. Octadecanoids are formed biosynthetically in mammals via cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P450 (CYP) activity, as well as nonenzymatically by photo- and autoxidation mechanisms. While octadecanoids are well-known mediators in plants, their role in the regulation of mammalian biological processes has been generally neglected. However, there have been significant advancements in recognizing the importance of these compounds in mammals and their involvement in the mediation of inflammation, nociception, and cell proliferation, as well as in immuno- and tissue modulation, coagulation processes, hormone regulation, and skin barrier formation. More recently, the gut microbiome has been shown to be a significant source of octadecanoid biosynthesis, providing additional biosynthetic routes including hydratase activity (e.g., CLA-HY, FA-HY1, FA-HY2). In this review, we summarize the current field of octadecanoids, propose standardized nomenclature, provide details of octadecanoid preparation and measurement, summarize the phase-I metabolic pathway of octadecanoid formation in mammals, bacteria, and fungi, and describe their biological activity in relation to mammalian pathophysiology as well as their potential use as biomarkers of health and disease.

Tumor Metabolic Reprogramming and Ferroptosis: The Impact of Glucose, Protein, and Lipid Metabolism

Ferroptosis, a novel form of cell death discovered in recent years, is typically accompanied by significant iron accumulation and lipid peroxidation during the process. This article systematically elucidates how tumor metabolic reprogramming affects the ferroptosis process in tumor cells. The paper outlines the basic concepts and physiological significance of tumor metabolic reprogramming and ferroptosis, and delves into the specific regulatory mechanisms of glucose metabolism, protein metabolism, and lipid metabolism on ferroptosis. We also explore how complex metabolic changes in the tumor microenvironment further influence the response of tumor cells to ferroptosis. Glucose metabolism modulates ferroptosis sensitivity by influencing intracellular energetic status and redox balance; protein metabolism, involving amino acid metabolism and protein synthesis, plays a crucial role in the initiation and progression of ferroptosis; and the relationship between lipid metabolism and ferroptosis primarily manifests in the generation and elimination of lipid peroxides. This review aims to provide a new perspective on how tumor cells regulate ferroptosis through metabolic reprogramming, with the ultimate goal of offering a theoretical basis for developing novel therapeutic strategies targeting tumor metabolism and ferroptosis.

Mechanism and application prospect of ferroptosis inhibitors in improving osteoporosis

Osteoporosis, a prevalent bone metabolic disorder, has emerged as a pressing global public health concern. Recent studies have illuminated a crucial link between ferroptosis and the pathogenesis of osteoporosis. Nevertheless, the intricate mechanisms underlying the role of ferroptosis in this condition remain largely unexplored. Therefore, this article comprehensively reviews the regulatory mechanisms of ferroptosis and the modulating effects on the development and progression of osteoporosis, as reported in recent years. Furthermore, this review summarizes the current state of the interventional strategies employed by both Western medicines and traditional Chinese medicines (TCMs) in addressing osteoporosis. This review aims to uncover potential novel avenues for the prevention and control of osteoporosis by synthesizing the modes of action and clinical efficacy of these therapeutic modalities.

STAT2/SLC27A3/PINK1-Mediated Mitophagy Remodeling Lipid Metabolism Contributes to Pazopanib Resistance in Clear Cell Renal Cell Carcinoma

Background: Clear cell renal cell carcinoma (ccRCC) is a prevalent malignant tumor of the urinary system. While tyrosine kinase inhibitors (TKIs) are currently the first-line treatments for advanced/metastatic ccRCC, patients often develop resistance after TKI therapy. Lipid metabolic reprogramming, a hallmark of tumor progression, contributes to acquired drug resistance in various malignant tumors. Mitophagy, a process that maintains mitochondrial homeostasis, aids tumor cells in adapting to microenvironmental changes and consequently developing drug resistance. Solute carrier family 27 member 3 (SLC27A3), highly expressed in lipid-rich tumors like ccRCC, has been associated with poor prognosis. However, the impact of SLC27A3 and the transcription factor complex containing STAT2 on lipid metabolic reprogramming, mitophagy in ccRCC, and their role in TKI resistance remain unexplored. Methods: 786-O to pazopanib resistance was induced by gradient increase of concentration, and the genes related to lipid metabolism were screened by RNA sequencing. Bioinformatics was used to analyze the differential expression of SLC27A3 and its effect on patient prognosis, and to predict the activated pathway in pazopanib-resistant cells. Lipid droplets (LDs) were detected by Red Oil O and BODIPY probe. Micro-targeted lipidomic of acyl-coenzyme A (CoA) and lipid metabolomics were performed to screen potential metabolites of SLC27A3. The differential expression of SLC27A3 was detected in clinical samples. The differential expression of SLC27A3 and its effect on drug resistance of ccRCC tumor were detected in vitro and in vivo. Mitophagy was detected by electron microscopy, Mtphagy probe, and Western blot. The mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) levels were detected by JC-1 and DCF probes. The binding site of the transcription factor complex to the SLC27A3 promoter was detected by dual-luciferase reporter gene assay. Results: SLC27A3, highly expressed in lipid-rich tumors such as ccRCC and glioblastoma, predicts poor prognosis. SLC27A3 expression level also increased in pazopanib-resistant 786-O cells (786-O-PR) with more LD accumulation compared to parental cells. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis from RNA sequencing showed that PINK1/Parkin-mediated mitophagy pathway was enriched in 786-O-PR. Knockdown of SLC27A3 markedly suppressed LD accumulation and mitophagy, and overcame pazopanib resistance in vitro and in vivo. Moreover, SLC27A3 functions as an acyl-CoA ligase catalyzing the formation of acyl-CoA, which refers to fatty acid oxidation accompanied by ROS production and synthesis of lipid. Overproduced acyl-CoA oxidation in mitochondria resulted in MMP decrease and amounts of ROS production, subsequently triggering PINK1/Parkin-mediated mitophagy. Moreover, mitophagy inhibition led to more ROS accumulation and cell death, indicating that mitophagy can keep ROS at an appropriate level by negative feedback. Mitophagy, simultaneously, prevented fatty acid oxidation in mitochondria by consuming CPT1A, forcing synthesis of triglycerides and cholesterol esters stored in LDs by transforming acyl-CoA, to support ccRCC progression. Besides, we found that STAT2 expression was positively correlated to SLC27A3. Transcriptional factor complex containing STAT2 could bind to the promoter of SLC27A3 mRNA to promote SLC27A3 transcription proved by dual-luciferase reporter assay, which also regulated LD metabolism and activated mitophagy during pazopanib resistance. Conclusion: SLC27A3 is up-regulated in pazopanib-resistant ccRCC and predicts poor prognosis. High expression of SLC27A3 produces excessive metabolites of various long-chain fatty acyl-CoA (12:0-, 16:0-, 17:0-, 20:3-CoA) to enter mitochondria for β-oxidation and produce amounts of ROS activating mitophagy. Subsequent mitophagy/ROS negative feedback controls ROS homeostasis and consumes CPT1A protein within mitochondria to suppress fatty acid β-oxidation, forcing acyl-CoA storage in LDs, mediating pazopanib resistance in ccRCC. Furthermore, STAT2 was identified as a core component of a potential upstream transcriptional factor complex for SLC27A3. Our findings shed new light on the underlying mechanism of SLC27A3 in ccRCC TKI resistance, which may provide a novel therapeutic target for the management of ccRCC.

The m6A eraser FTO suppresses ferroptosis via mediating ACSL4 in LPS-induced macrophage inflammation

Acute lung injury (ALI) is a serious disorder characterized by the release of pro-inflammatory cytokines and cascade activation of macrophages. Ferroptosis, a form of iron-dependent cell death triggered by intracellular phospholipid peroxidation, has been implicated as an internal mechanism underlying ALI. In this study, we investigated the effects of m6A demethylase fat mass and obesity-associated protein (FTO) on the inhibition of macrophage ferroptosis in ALI. Using a mouse model of lipopolysaccharide (LPS)-induced ALI, we observed the induction of ferroptosis and its co-localization with the macrophage marker F4/80, suggesting that ferroptosis might be induced in macrophages. Ferroptosis was promoted during LPS-induced inflammation in macrophages in vitro, and the inflammation was counteracted by the ferroptosis inhibitor ferrostatin-1 (fer-1). Given that FTO showed lower expression levels in the lung tissue of mice with ALI and inflammatory macrophages, we further dissected the regulatory capacity of FTO in ferroptosis. The results demonstrated that FTO alleviated macrophage inflammation by inhibiting ferroptosis. Mechanistically, FTO decreased the stability of ACSL4 mRNA via YTHDF1, subsequently inhibiting ferroptosis and inflammation by interrupting polyunsaturated fatty acid consumption. Moreover, FTO downregulated the synthesis and secretion of prostaglandin E2, thereby reducing ferroptosis and inflammation. In vivo, the FTO inhibitor FB23-2 aggravated lung injury, the inflammatory response, and ferroptosis in mice with ALI; however, fer-1 therapy mitigated these effects. Overall, our findings revealed that FTO may function as an inhibitor of the inflammatory response driven by ferroptosis, emphasizing its potential as a target for ALI treatment.

Rosiglitazone retards the progression of iron overload-induced osteoarthritis by impeding chondrocyte ferroptosis

Ferroptosis is implicated in several diseases, including iron overload-induced osteoarthritis (IOOA), which is marked by oxidative stress, iron imbalance, and lipid peroxidation. Given rosiglitazone's (RSG) ability to inhibit lipid peroxidation and ferroptosis, this study aims to assess its therapeutic potential for treating IOOA. Our in vitro results show that RSG targets acyl-CoA synthetase long-chain family member 4 to mitigate impairments induced by interleukin-1 beta and ferric ammonium citrate, including cell apoptosis, senescence, inflammatory responses, extracellular matrix degradation, and ferroptosis. RSG reduced intracellular iron content, alleviated oxidative stress and lipid peroxidation, mitigated damage to membrane-bound organelles, and enhanced glucose transport. Additionally, pre-treatment with RSG imparted anti-ferroptotic properties to chondrocytes. In vivo, RSG alleviated cartilage degradation, inflammatory responses, and ferroptosis in mice with IOOA. In conclusion, RSG exhibits chondroprotective and anti-ferroptotic effects by suppressing lipid peroxidation and restoring iron homeostasis, highlighting its potential for treating IOOA.

Unveiling ferroptosis as a promising therapeutic avenue for colorectal cancer and colitis treatment

Ferroptosis is a novel type of regulated cell death (RCD) involving iron accumulation and lipid peroxidation. Since its discovery in 2012, various studies have shown that ferroptosis is associated with the pathogenesis of various diseases. Ferroptotic cell death has also been linked to intestinal dysfunction but can act as either a positive or negative regulator of intestinal disease, depending on the cell type and disease context. The continued investigation of mechanisms underlying ferroptosis provides a wealth of potential for developing novel treatments. Considering the growing prevalence of intestinal diseases, particularly colorectal cancer (CRC) and inflammatory bowel disease (IBD), this review article focuses on potential therapeutics targeting the ferroptotic pathway in relation to CRC and IBD.

Functional Insights into the Sphingolipids C1P, S1P, and SPC in Human Fibroblast-like Synoviocytes by Proteomic Analysis

The (patho)physiological function of the sphingolipids ceramide-1-phosphate (C1P), sphingosine-1-phosphate (S1P), and sphingosylphosphorylcholine (SPC) in articular joints during osteoarthritis (OA) is largely unknown. Therefore, we investigated the influence of these lipids on protein expression by fibroblast-like synoviocytes (FLSs) from OA knees. Cultured human FLSs (n = 7) were treated with 1 of 3 lipid species-C1P, S1P, or SPC-IL-1β, or with vehicle. The expression of individual proteins was determined by tandem mass tag peptide labeling followed by high-resolution electrospray ionization (ESI) mass spectrometry after liquid chromatographic separation (LC-MS/MS/MS). The mRNA levels of selected proteins were analyzed using RT-PCR. The 3sphingolipids were quantified in the SF of 18 OA patients using LC-MS/MS. A total of 4930 proteins were determined using multiplex MS, of which 136, 9, 1, and 0 were regulated both reproducibly and significantly by IL-1β, C1P, S1P, and SPC, respectively. In the presence of IL-1ß, all 3 sphingolipids exerted ancillary effects. Only low SF levels of C1P and SPC were found. In conclusion, the 3 lipid species regulated proteins that have not been described in OA. Our results indicate that charged multivesicular body protein 1b, metal cation symporter ZIP14, glutamine-fructose-6-P transaminase, metallothionein-1F and -2A, ferritin, and prosaposin are particularly interesting proteins due to their potential to affect inflammatory, anabolic, catabolic, and apoptotic mechanisms.

Molecular Mechanisms and Therapeutic Targeting of Ferroptosis in Doxorubicin-Induced Cardiotoxicity

Ferroptosis, an iron-dependent form of regulated cell death, has received increasing attention for its pathophysiologic contribution to the onset and development of doxorubicin-induced cardiotoxicity. Moreover, modulation of ferroptosis with specific inhibitors may provide new therapeutic opportunities for doxorubicin-induced cardiotoxicity. Here, we will review the molecular mechanisms and therapeutic promise of targeting ferroptosis in doxorubicin-induced cardiotoxicity.

Targeting Metabolic Syndrome Pathways: Carrot microRNAs As Potential Modulators

Metabolic syndrome is a condition characterized by metabolic alterations that culminate in chronic noncommunicable diseases of high morbidity and mortality, such as cardiovascular diseases, type 2 diabetes, nonalcoholic fatty liver disease, and colon cancer. Developing new therapeutic strategies with a multifactorial approach is important since current therapies focus on only one or two components of the metabolic syndrome. In this sense, plant-based gene regulation represents an innovative strategy to prevent or modulate human metabolic pathologies, including metabolic syndrome. Here, using a computational and systems biology approach, it was found that carrot microRNAs can modulate key BMPs/SMAD signaling members, C/EBPs, and KLFs involved in several aspects associated with metabolic syndrome, including the hsa04350:TGF-beta signaling pathway, hsa04931:insulin resistance, hsa04152:AMPK signaling pathway, hsa04933:AGE-RAGE signaling pathway in diabetic complications, hsa04010:MAPK signaling pathway, hsa04350:TGF-beta signaling pathway, hsa01522:endocrine resistance, and hsa04910:insulin signaling pathway. These data demonstrated the potential applications of carrot microRNAs as effective food-based therapeutics for obesity and associated metabolic diseases.

Lipid droplets provide metabolic flexibility for cancer progression

A hallmark of cancer cells is their remarkable ability to efficiently adapt to favorable and hostile environments. Due to a unique metabolic flexibility, tumor cells can grow even in the absence of extracellular nutrients or in stressful scenarios. To achieve this, cancer cells need large amounts of lipids to build membranes, synthesize lipid-derived molecules, and generate metabolic energy in the absence of other nutrients. Tumor cells potentiate strategies to obtain lipids from other cells, metabolic pathways to synthesize new lipids, and mechanisms for efficient storage, mobilization, and utilization of these lipids. Lipid droplets (LDs) are the organelles that collect and supply lipids in eukaryotes and it is increasingly recognized that the accumulation of LDs is a new hallmark of cancer cells. Furthermore, an active role of LD proteins in processes underlying tumorigenesis has been proposed. Here, by focusing on three major classes of LD-resident proteins (perilipins, lipases, and acyl-CoA synthetases), we provide an overview of the contribution of LDs to cancer progression and discuss the role of LD proteins during the proliferation, invasion, metastasis, apoptosis, and stemness of cancer cells.

Studying the topology of peroxisomal acyl-CoA synthetases using self-assembling split sfGFP

Peroxisomes are membrane-bounded organelles that contain enzymes involved in multiple lipid metabolic pathways. Several of these pathways require (re-)activation of fatty acids to coenzyme A (CoA) esters by acyl-CoA synthetases, which may take place inside the peroxisomal lumen or extraperoxisomal. The acyl-CoA synthetases SLC27A2, SLC27A4, ACSL1, and ACSL4 have different but overlapping substrate specificities and were previously reported to be localized in the peroxisomal membrane in addition to other subcellular locations. However, it has remained unclear if the catalytic acyl-CoA synthetase sites of these enzymes are facing the peroxisomal lumen or the cytosolic side of the peroxisomal membrane. To study this topology in cellulo we have developed a microscopy-based method that uses the previously developed self-assembling split superfolder (sf) green fluorescent protein (GFP) assay. We show that this self-assembling split sfGFP method can be used to study the localization as well as the topology of membrane proteins in the peroxisomal membrane, but that it is less suited to study the location of soluble peroxisomal proteins. With the method we could demonstrate that the acyl-CoA synthetase domains of the peroxisome-bound acyl-CoA synthetases SLC27A2 and SLC27A4 are oriented toward the peroxisomal lumen and the domain of ACSL1 toward the cytosol. In contrast to previous reports, ACSL4 was not found in peroxisomes.

Ferroptosis: Mechanisms and role in diabetes mellitus and its complications

Diabetes mellitus (DM) and its complications are major diseases that affect human health and pose a serious threat to global public health. Although the prevention and treatment of DM and its complications are constantly being revised, optimal treatment strategies remain unavailable. Further exploration of new anti-diabetic strategies is an arduous task. Revealing the pathological changes and molecular mechanisms of DM and its complications is the cornerstone for exploring new therapeutic strategies. Ferroptosis is a type of newly discovered iron-dependent regulated cell death. Notably, the role of ferroptosis in the occurrence, development, and pathogenesis of DM and its complications has gradually been revealed. Numerous studies have shown that ferroptosis plays an important role in the pathophysiology and pathogenesis of DM and its associated complications. The aim of this review is to discuss the known underlying mechanisms of ferroptosis, the relationship between ferroptosis and DM, and the relationship between ferroptosis as a mode of cell death and diabetic kidney disease, diabetic retinopathy, diabetic cardiomyopathy, diabetic osteoporosis, diabetes-associated cognitive dysfunction, DM-induced erectile dysfunction, and diabetic atherosclerosis.

Not So Rare: Diseases Based on Mutant Proteins Controlling Endoplasmic Reticulum-Mitochondria Contact (MERC) Tethering

Mitochondria-endoplasmic reticulum contacts (MERCs), also called endoplasmic reticulum (ER)-mitochondria contact sites (ERMCS), are the membrane domains, where these two organelles exchange lipids, Ca2+ ions, and reactive oxygen species. This crosstalk is a major determinant of cell metabolism, since it allows the ER to control mitochondrial oxidative phosphorylation and the Krebs cycle, while conversely, it allows the mitochondria to provide sufficient ATP to control ER proteostasis. MERC metabolic signaling is under the control of tethers and a multitude of regulatory proteins. Many of these proteins have recently been discovered to give rise to rare diseases if their genes are mutated. Surprisingly, these diseases share important hallmarks and cause neurological defects, sometimes paired with, or replaced by skeletal muscle deficiency. Typical symptoms include developmental delay, intellectual disability, facial dysmorphism and ophthalmologic defects. Seizures, epilepsy, deafness, ataxia, or peripheral neuropathy can also occur upon mutation of a MERC protein. Given that most MERC tethers and regulatory proteins have secondary functions, some MERC protein-based diseases do not fit into this categorization. Typically, however, the proteins affected in those diseases have dominant functions unrelated to their roles in MERCs tethering or their regulation. We are discussing avenues to pharmacologically target genetic diseases leading to MERC defects, based on our novel insight that MERC defects lead to common characteristics in rare diseases. These shared characteristics of MERCs disorders raise the hope that they may allow for similar treatment options.

Towards a Unitary Hypothesis of Alzheimer's Disease Pathogenesis

The "amyloid cascade" hypothesis of Alzheimer's disease (AD) pathogenesis invokes the accumulation in the brain of plaques (containing the amyloid-β protein precursor [AβPP] cleavage product amyloid-β [Aβ]) and tangles (containing hyperphosphorylated tau) as drivers of pathogenesis. However, the poor track record of clinical trials based on this hypothesis suggests that the accumulation of these peptides is not the only cause of AD. Here, an alternative hypothesis is proposed in which the AβPP cleavage product C99, not Aβ, is the main culprit, via its role as a regulator of cholesterol metabolism. C99, which is a cholesterol sensor, promotes the formation of mitochondria-associated endoplasmic reticulum (ER) membranes (MAM), a cholesterol-rich lipid raft-like subdomain of the ER that communicates, both physically and biochemically, with mitochondria. We propose that in early-onset AD (EOAD), MAM-localized C99 is elevated above normal levels, resulting in increased transport of cholesterol from the plasma membrane to membranes of intracellular organelles, such as ER/endosomes, thereby upregulating MAM function and driving pathology. By the same token, late-onset AD (LOAD) is triggered by any genetic variant that increases the accumulation of intracellular cholesterol that, in turn, boosts the levels of C99 and again upregulates MAM function. Thus, the functional cause of AD is upregulated MAM function that, in turn, causes the hallmark disease phenotypes, including the plaques and tangles. Accordingly, the MAM hypothesis invokes two key interrelated elements, C99 and cholesterol, that converge at the MAM to drive AD pathogenesis. From this perspective, AD is, at bottom, a lipid disorder.

Targeting Ferroptosis: A Novel Strategy for the Treatment of Atherosclerosis

Since ferroptosis was reported in 2012, its application prospects in various diseases have been widely considered, initially as a treatment direction for tumors. Recent studies have shown that ferroptosis is closely related to the occurrence and development of atherosclerosis. The primary mechanism is to affect the occurrence and development of atherosclerosis through intracellular iron homeostasis, ROS and lipid peroxide production and metabolism, and a variety of intracellular signaling pathways. Inhibition of ferroptosis is effective in inhibiting the development of atherosclerosis, and it can bring a new direction for treating atherosclerosis. In this review, we discuss the mechanism of ferroptosis and focus on the relationship between ferroptosis and atherosclerosis, summarize the different types of ferroptosis inhibitors that have been widely studied, and discuss some issues worthy of attention in the treatment of atherosclerosis by targeting ferroptosis.

Emerging Therapeutic Approaches Targeting Ferroptosis in Cancer: Focus on Immunotherapy and Nanotechnology

Ferroptosis is a newly discovered form of programmed cell death characterized by iron overload, ROS accumulation, and lipid peroxidation. It is distinguished by unique morphological, biochemical, and genetic features and stands apart from other known regulated cell death mechanisms. Studies have demonstrated a close association between ferroptosis and various cancers, including liver cancer, lung cancer, renal cell carcinoma, colorectal cancer, pancreatic cancer, and ovarian cancer. Inducing ferroptosis has shown promising results in inhibiting tumor growth and reversing tumor progression. However, the challenge lies in regulating ferroptosis in vivo due to the scarcity of potent compounds that can activate it. Integrating emerging biomedical discoveries and technological innovations with conventional therapies is imperative. Notably, considerable progress has been made in cancer treatment by leveraging immunotherapy and nanotechnology to trigger ferroptosis. This review explores the relationship between ferroptosis and emerging immunotherapies and nanotechnologies, along with their potential underlying mechanisms, offering valuable insights for developing novel cancer treatment strategies.

Ferroptosis: Emerging Role in Diseases and Potential Implication of Bioactive Compounds

Ferroptosis is a form of cell death that is distinguished from other types of death for its peculiar characteristics of death regulated by iron accumulation, increase in ROS, and lipid peroxidation. In the past few years, experimental evidence has correlated ferroptosis with various pathological processes including neurodegenerative and cardiovascular diseases. Ferroptosis also is involved in several types of cancer because it has been shown to induce tumor cell death. In particular, the pharmacological induction of ferroptosis, contributing to the inhibition of the proliferative process, provides new ideas for the pharmacological treatment of cancer. Emerging evidence suggests that certain mechanisms including the Xc- system, GPx4, and iron chelators play a key role in the regulation of ferroptosis and can be used to block the progression of many diseases. This review summarizes current knowledge on the mechanism of ferroptosis and the latest advances in its multiple regulatory pathways, underlining ferroptosis' involvement in the diseases. Finally, we focused on several types of ferroptosis inducers and inhibitors, evaluating their impact on the cell death principal targets to provide new perspectives in the treatment of the diseases and a potential pharmacological development of new clinical therapies.

lnc-HC ameliorates steatosis by promoting miR-130b-3p biogenesis and the assembly of an RNA-induced silencing complex

Hepatic lipid deposition is the main cause of non-alcoholic fatty liver disease (NAFLD). Our previous study identified that lnc-HC prevents NAFLD by increasing the expression of miR-130b-3p. In the present study, we show that lnc-HC, an lncRNA derived from hepatocytes, positively controls miR-130b-3p maturation at multiple levels and contributes to its action by enhancing the assembly of an RNA-induced silencing complex (RISC). lnc-HC negatively regulates the downstream target genes of miR-130b-3p, including peroxisome proliferator-activated receptor gamma (PPARγ) and acyl-CoA synthetase long-chain family member 1 and 4 (Acsl1 and Acsl4, respectively), thus suppressing hepatic lipid droplet accumulation. Mechanistically, lnc-HC enhanced the promoter activity of miR-130b-3p by positively regulating the expression of transcription factors MAF bZIP transcription factor B (Mafb) and Jun proto-oncogene (Jun). Then, lnc-HC contributed the processing step of primary (pri-) miR-130b and strengthened the interaction between Drosha enzyme and the 5'-flanking sequence of pri-miR-130b to produce more precursor transcripts. Through direct binding with the chaperone heat shock protein 90 alpha family class A member 1 (HSP90AA1), lnc-HC contributed to RISC assembly, which was composed of HSP90AA1, argonaute RISC catalytic component 2 (AGO2) and miR-130b-3p. In a high-fat, high-cholesterol-induced hepatic lipid disorder E3 model, we confirmed that the hepatic expression of lnc-HC/miR-130b-3p negatively correlated with that of the target genes and was closely associated with liver triglycerides concentration. These findings provide a deeper understanding of the regulatory roles of lnc-HC in hepatic lipid metabolism and NAFLD development.

Deficiency of long-chain acyl-CoA synthetase 4 leads to lipopolysaccharide-induced mortality in a mouse model of septic shock

Long-chain acyl-CoA synthetase 4 (ACSL4) converts free highly unsaturated fatty acids (HUFAs) into their acyl-CoA esters and is important for HUFA utilization. HUFA-containing phospholipids produced via ACSL4-dependent reactions are involved in pathophysiological events such as inflammatory responses and ferroptosis as a source for lipid mediators and/or a target of oxidative stress, respectively. However, the in vivo role of ACSL4 in inflammatory responses is not fully understood. This study sought to define the effects of ACSL4 deficiency on lipopolysaccharide (LPS)-induced systemic inflammatory responses using global Acsl4 knockout (Acsl4 KO) mice. Intraperitoneal injection of LPS-induced more severe symptoms, including diarrhea, hypothermia, and higher mortality, in Acsl4 KO mice within 24 h compared with symptoms in wild-type (WT) mice. Intestinal permeability induced 3 h after LPS challenge was also enhanced in Acsl4 KO mice compared with that in WT mice. In addition, plasma levels of some eicosanoids in Acsl4 KO mice 6 h post-LPS injection were 2- to 9-fold higher than those in WT mice. The increased mortality observed in LPS-treated Acsl4 KO mice was significantly improved by treatment with the general cyclooxygenase inhibitor indomethacin with a partial reduction in the severity of illness index for hypothermia, diarrhea score, and intestinal permeability. These results suggest that ACSL4 deficiency enhances susceptibility to endotoxin at least partly through the overproduction of cyclooxygenase-derived eicosanoids.

Broodstock nutritional programming differentially affects the hepatic transcriptome and genome-wide DNA methylome of farmed gilthead sea bream (Sparus aurata) depending on genetic background

BACKGROUND

Broodstock nutritional programming improves the offspring utilization of plant-based diets in gilthead sea bream through changes in hepatic metabolism. Attention was initially focused on fatty acid desaturases, but it can involve a wide range of processes that remain largely unexplored. How all this can be driven by a different genetic background is hardly underlined, and the present study aimed to assess how broodstock nutrition affects differentially the transcriptome and genome-wide DNA methylome of reference and genetically selected fish within the PROGENSA® selection program.

RESULTS

After the stimulus phase with a low fish oil diet, two offspring subsets of each genetic background received a control or a FUTURE-based diet. This highlighted a different hepatic transcriptome (RNA-seq) and genome-wide DNA methylation (MBD-seq) pattern depending on the genetic background. The number of differentially expressed transcripts following the challenge phase varied from 323 in reference fish to 2,009 in genetically selected fish. The number of discriminant transcripts, and associated enriched functions, were also markedly higher in selected fish. Moreover, correlation analysis depicted a hyper-methylated and down-regulated gene expression state in selected fish with the FUTURE diet, whereas the opposite pattern appeared in reference fish. After filtering for highly represented functions in selected fish, 115 epigenetic markers were retrieved in this group. Among them, lipid metabolism genes (23) were the most reactive following ordering by fold-change in expression, rendering a final list of 10 top markers with a key role on hepatic lipogenesis and fatty acid metabolism (cd36, pitpna, cidea, fasn, g6pd, lipt1, scd1a, acsbg2, acsl14, acsbg2).

CONCLUSIONS

Gene expression profiles and methylation signatures were dependent on genetic background in our experimental model. Such assumption affected the magnitude, but also the type and direction of change. Thus, the resulting epigenetic clock of reference fish might depict an older phenotype with a lower methylation for the epigenetically responsive genes with a negative methylation-expression pattern. Therefore, epigenetic markers will be specific of each genetic lineage, serving the broodstock programming in our selected fish to prevent and mitigate later in life the risk of hepatic steatosis through changes in hepatic lipogenesis and fatty acid metabolism.

Acyl-CoA synthase ACSL4: an essential target in ferroptosis and fatty acid metabolism

ABSTRACT

Long-chain acyl-coenzyme A (CoA) synthase 4 (ACSL4) is an enzyme that esterifies CoA into specific polyunsaturated fatty acids, such as arachidonic acid and adrenic acid. Based on accumulated evidence, the ACSL4-catalyzed biosynthesis of arachidonoyl-CoA contributes to the execution of ferroptosis by triggering phospholipid peroxidation. Ferroptosis is a type of programmed cell death caused by iron-dependent peroxidation of lipids; ACSL4 and glutathione peroxidase 4 positively and negatively regulate ferroptosis, respectively. In addition, ACSL4 is an essential regulator of fatty acid (FA) metabolism. ACSL4 remodels the phospholipid composition of cell membranes, regulates steroidogenesis, and balances eicosanoid biosynthesis. In addition, ACSL4-mediated metabolic reprogramming and antitumor immunity have attracted much attention in cancer biology. Because it facilitates the cross-talk between ferroptosis and FA metabolism, ACSL4 is also a research hotspot in metabolic diseases and ischemia/reperfusion injuries. In this review, we focus on the structure, biological function, and unique role of ASCL4 in various human diseases. Finally, we propose that ACSL4 might be a potential therapeutic target.

The Intersection between Bacterial Metabolism and Innate Immunity

BACKGROUND

The innate immune system is the first line of defense against microbial pathogens and is essential for maintaining good health. If pathogens breach innate barriers, the likelihood of infection is significantly increased. Many bacterial pathogens pose a threat to human health on account of their ability to evade innate immunity and survive in growth-restricted environments. These pathogens have evolved sophisticated strategies to obtain nutrients as well as manipulate innate immune responses, resulting in disease or chronic infection.

SUMMARY

The relationship between bacterial metabolism and innate immunity is complex. Although aspects of bacterial metabolism can be beneficial to the host, particularly those related to the microbiota and barrier integrity, others can be harmful. Several bacterial pathogens harness metabolism to evade immune responses and persist during infection. The study of these adaptive traits provides insight into the roles of microbial metabolism in pathogenesis that extend beyond energy balance. This review considers recent studies on bacterial metabolic pathways that promote infection by circumventing several facets of the innate immune system. We also discuss relationships between innate immunity and antibiotics and highlight future directions for research in this field.

KEY MESSAGES

Pathogenic bacteria have a remarkable capacity to harness metabolism to manipulate immune responses and promote pathogenesis. While we are beginning to understand the multifaceted and complex metabolic adaptations that occur during infection, there is still much to uncover with future research.

Current progress of ferroptosis in cardiovascular diseases

Ferroptosis, a newly recognized form of nonapoptotic regulated cell death, is characterized by iron-dependent lipid peroxidation. Biological processes, such as iron metabolism, lipid peroxidation, and amino acid metabolism, are involved in the process of ferroptosis. However, the related molecular mechanism of ferroptosis has not yet been completely clarified, and specific and sensitive biomarkers for ferroptosis need to be explored. Recently, studies have revealed that ferroptosis probably causes or exacerbates the progress of cardiovascular diseases, and could be the potential therapeutic target for cardiovascular diseases. In this review, we summarize the molecular mechanisms regulating ferroptosis, inducers or inhibitors of ferroptosis, and the current progresses of ferroptosis in cardiovascular diseases. Furthermore, we discuss the emerging challenges and future perspectives, which may provide novel insights into the treatment of cardiovascular diseases.

A new mechanism of therapeutic effect of stachydrine on heart failure by inhibiting myocardial ferroptosis

Ferroptosis is a novel form of programmed cell death caused by iron-dependent lipid peroxidation and excessive production of ROS. Its morphology is characterized by mitochondrial atrophy, increased mitochondrial membrane density, mitochondrial cristae degeneration and rupture, and unchanged nuclear morphology. Here, we investigated whether a bioactive constituent extracted from the Chinese herb Leonurus japonicus Houtt. (Yimucao), stachydrine, could improve cardiac function by inhibiting myocardial ferroptosis. We found significant morphological features of ferroptosis in a TAC-induced mouse model of heart failure, in which increased lipid peroxidation in cardiac tissue was accompanied by abnormalities in cystine metabolism as well as iron metabolism. The contractile function of adult mouse cardiomyocytes was severely reduced after the occurrence of erastin-induced ferroptosis. We found that in heart failure mice and erastin-induced cardiomyocyte ferroptosis models, stachydrine significantly improved myocardial function, improving mitochondrial morphological features of ferroptosis and associated signaling pathway alterations, including lipid peroxidation levels, cystine metabolism, and iron metabolism. The results of studies on stachydrine provides new inspirations for the treatment of cardiac ferroptosis and chronic heart failure.

The elucidation of plasma lipidome profiles during severe influenza in a mouse model

Although influenza virus infection has been shown to affect lipid metabolism, details remain unknown. Therefore, we elucidated the kinetic lipid profiles of mice infected with different doses of influenza virus A/Puerto Rico/8/34 (H1N1) (PR8) by measuring multiple lipid molecular species using untargeted lipidomic analysis. C57BL/6 male mice were intranasally infected with PR8 virus at 50 or 500 plaque-forming units to cause sublethal or lethal influenza, respectively. Plasma and tissue samples were collected at 1, 3, and 6 days post-infection (dpi), and comprehensive lipidomic analysis was performed using high-performance liquid chromatography-linear trap quadrupole-Orbitrap mass spectrometry, as well as gene expression analyses. The most prominent feature of the lipid profile in lethally infected mice was the elevated plasma concentrations of phosphatidylethanolamines (PEs) containing polyunsaturated fatty acid (PUFA) at 3 dpi. Furthermore, the facilitation of PUFA-containing phospholipid production in the lungs, but not in the liver, was suggested by gene expression and lipidomic analysis of tissue samples. Given the increased plasma or serum levels of PUFA-containing PEs in patients with other viral infections, especially in severe cases, the elevation of these phospholipids in circulation could be a biomarker of infection and the severity of infectious diseases.

The ACSL4 Network Regulates Cell Death and Autophagy in Diseases

Lipid metabolism, cell death, and autophagy are interconnected processes in cells. Dysregulation of lipid metabolism can lead to cell death, such as via ferroptosis and apoptosis, while lipids also play a crucial role in the regulation of autophagosome formation. An increased autophagic response not only promotes cell survival but also causes cell death depending on the context, especially when selectively degrading antioxidant proteins or organelles that promote ferroptosis. ACSL4 is an enzyme that catalyzes the formation of long-chain acyl-CoA molecules, which are important intermediates in the biosynthesis of various types of lipids. ACSL4 is found in many tissues and is particularly abundant in the brain, liver, and adipose tissue. Dysregulation of ACSL4 is linked to a variety of diseases, including cancer, neurodegenerative disorders, cardiovascular disease, acute kidney injury, and metabolic disorders (such as obesity and non-alcoholic fatty liver disease). In this review, we introduce the structure, function, and regulation of ACSL4; discuss its role in apoptosis, ferroptosis, and autophagy; summarize its pathological function; and explore the potential implications of targeting ACSL4 in the treatment of various diseases.

ACSL4-Mediated Ferroptosis and Its Potential Role in Central Nervous System Diseases and Injuries

As an iron-dependent regulated form of cell death, ferroptosis is characterized by iron-dependent lipid peroxidation and has been implicated in the occurrence and development of various diseases, including nervous system diseases and injuries. Ferroptosis has become a potential target for intervention in these diseases or injuries in relevant preclinical models. As a member of the Acyl-CoA synthetase long-chain family (ACSLs) that can convert saturated and unsaturated fatty acids, Acyl-CoA synthetase long-chain familymember4 (ACSL4) is involved in the regulation of arachidonic acid and eicosapentaenoic acid, thus leading to ferroptosis. The underlying molecular mechanisms of ACSL4-mediated ferroptosis will promote additional treatment strategies for these diseases or injury conditions. Our review article provides a current view of ACSL4-mediated ferroptosis, mainly including the structure and function of ACSL4, as well as the role of ACSL4 in ferroptosis. We also summarize the latest research progress of ACSL4-mediated ferroptosis in central nervous system injuries and diseases, further proving that ACSL4-medicated ferroptosis is an important target for intervention in these diseases or injuries.

Oxaliplatin-induced cardiotoxicity in mice is connected to the changes in energy metabolism in the heart tissue

Oxaliplatin is a platinum-based alkylating chemotherapeutic agent used for cancer treatment. At high cumulative dosage, the negative effect of oxaliplatin on the heart becomes evident and is linked to a growing number of clinical reports. The aim of this study was to determine how chronic oxaliplatin treatment causes the changes in energy-related metabolic activity in the heart that leads to cardiotoxicity and heart damage in mice. C57BL/6 male mice were treated with a human equivalent dosage of intraperitoneal oxaliplatin (0 and 10 mg/kg) once a week for eight weeks. During the treatment, mice were followed for physiological parameters, ECG, histology and RNA sequencing of the heart. We identified that oxaliplatin induces strong changes in the heart and affects the heart's energy-related metabolic profile. Histological post-mortem evaluation identified focal myocardial necrosis infiltrated with a small number of associated neutrophils. Accumulated doses of oxaliplatin led to significant changes in gene expression related to energy related metabolic pathways including fatty acid (FA) oxidation, amino acid metabolism, glycolysis, electron transport chain, and NAD synthesis pathway. At high accumulative doses of oxaliplatin, the heart shifts its metabolism from FAs to glycolysis and increases lactate production. It also leads to strong overexpression of genes in NAD synthesis pathways such as Nmrk2. Changes in gene expression associated with energy metabolic pathways can be used to develop diagnostic methods to detect oxaliplatin-induced cardiotoxicity early on as well as therapy to compensate for the energy deficit in the heart to prevent heart damage.

B cell-derived anti-beta 2 glycoprotein I antibody mediates hyperhomocysteinemia-aggravated hypertensive glomerular lesions by triggering ferroptosis

Hyperhomocysteinemia (HHcy) is a risk factor for chronic kidney diseases (CKDs) that affects about 85% CKD patients. HHcy stimulates B cells to secrete pathological antibodies, although it is unknown whether this pathway mediates kidney injury. In HHcy-treated 2-kidney, 1-clip (2K1C) hypertensive murine model, HHcy-activated B cells secreted anti-beta 2 glycoprotein I (β₂GPI) antibodies that deposited in glomerular endothelial cells (GECs), exacerbating glomerulosclerosis and reducing renal function. Mechanistically, HHcy 2K1C mice increased phosphatidylethanolamine (PE) (18:0/20:4, 18:0/22:6, 16:0/20:4) in kidney tissue, as determined by lipidomics. GECs oxidative lipidomics validated the increase of oxidized phospholipids upon Hcy-activated B cells culture medium (Hcy-B CM) treatment, including PE (18:0/20:4 + 3[O], PE (18:0a/22:4 + 1[O], PE (18:0/22:4 + 2[O] and PE (18:0/22:4 + 3[O]). PE synthases ethanolamine kinase 2 (etnk2) and ethanolamine-phosphate cytidylyltransferase 2 (pcyt2) were increased in the kidney GECs of HHcy 2K1C mice and facilitated polyunsaturated PE synthesis to act as lipid peroxidation substrates. In HHcy 2K1C mice and Hcy-B CM-treated GECs, the oxidative environment induced by iron accumulation and the insufficient clearance of lipid peroxides caused by transferrin receptor (TFR) elevation and down-regulation of SLC7A11/glutathione peroxidase 4 (GPX4) contributed to GECs ferroptosis of the kidneys. In vivo, pharmacological depletion of B cells or inhibition of ferroptosis mitigated the HHcy-aggravated hypertensive renal injury. Consequently, our findings uncovered a novel mechanism by which B cell-derived pathogenic anti-β₂GPI IgG generated by HHcy exacerbated hypertensive kidney damage by inducing GECs ferroptosis. Targeting B cells or ferroptosis may be viable therapeutic strategies for ameliorating lipid peroxidative renal injury in HHcy patients with hypertensive nephropathy.

Fighting age-related orthopedic diseases: focusing on ferroptosis

Ferroptosis, a unique type of cell death, is characterized by iron-dependent accumulation and lipid peroxidation. It is closely related to multiple biological processes, including iron metabolism, polyunsaturated fatty acid metabolism, and the biosynthesis of compounds with antioxidant activities, including glutathione. In the past 10 years, increasing evidence has indicated a potentially strong relationship between ferroptosis and the onset and progression of age-related orthopedic diseases, such as osteoporosis and osteoarthritis. Therefore, in-depth knowledge of the regulatory mechanisms of ferroptosis in age-related orthopedic diseases may help improve disease treatment and prevention. This review provides an overview of recent research on ferroptosis and its influences on bone and cartilage homeostasis. It begins with a brief overview of systemic iron metabolism and ferroptosis, particularly the potential mechanisms of ferroptosis. It presents a discussion on the role of ferroptosis in age-related orthopedic diseases, including promotion of bone loss and cartilage degradation and the inhibition of osteogenesis. Finally, it focuses on the future of targeting ferroptosis to treat age-related orthopedic diseases with the intention of inspiring further clinical research and the development of therapeutic strategies.

Ferroptosis, Acyl Starvation, and Breast Cancer

To maintain their growth rate, cancer cells must secure a supply of fatty acids, which are necessary for building cell membranes and maintaining energy processes. This is one of the reasons why tissues with intensive fatty acid metabolism, such as the mammary gland, are more likely to develop tumors. One natural or induced defense process against cancer is ferroptosis, which interferes with normal fatty acid metabolism. This leads to the oxidation of polyunsaturated fatty acids, which causes a rearrangement of the metabolism and damages cell membranes. As a consequence of this oxidation, there is a shortage of normal polyunsaturated fatty acids, which disturbs the complicated metabolism of fatty acids. This imbalance in metabolism, resulting from the deficiency of properly structured fatty acids, is called, by these authors, "acyl starvation." When cancer cells are exposed to alternating hypoxia and reoxygenation, they often develop resistance to neoadjuvant therapies. Blocking the stearoyl-CoA desaturase - fatty acid-binding protein 4 - fatty acid translocase axis appears to be a promising pathway in the treatment of breast cancer. On the one hand, the inhibition of desaturase leads to the formation of toxic phospholipid hydroperoxides in ferroptosis, whereas on the other hand, the inhibition of fatty acid-binding protein 4 and translocase leads to a reduced uptake of fatty acids and disruption of the cellular transport of fatty acids, resulting in intracellular acyl starvation. The disruption in the metabolism of fatty acids in cancer cells may augment the effectiveness of neoadjuvant therapy. SIGNIFICANCE STATEMENT: Regulation of the metabolism of fatty acids in cancer cells seems to be a promising therapeutic direction. Studies show that the induction of ferroptosis in cancer cells, combined with use of neoadjuvant therapies, effectively inhibits the proliferation of these cells. We link the process of ferroptosis with apoptosis and SCD1-FABP4-CD36 axis and propose the term "acyl starvation" for the processes leading to FA deficiency, dysregulation of FA metabolism in cancer cells, and, most importantly, the appearance of incorrect proportions FAs.

Endometrial microbial alterations disrupt endometrial immune homeostasis by overactivation of Eicosapentaenoic acid biosynthesis leading to altered endometrial receptivity

Embryo implantation is a key step in human reproduction, and the endometrium plays a key role in this process. Changes in the receptive state of the endometrium are one of the main reasons for embryo implantation failure. However, the mechanism underlying the altered endometrial receptivity remains unclear. In this study, we recruited 140 women undergoing assisted reproductive technology and divided them into a shifting group and a normal group based on their embryo implantation window results. Endometrial transcriptome data suggested that changes in the remodeling process of decidual spiral arterioles and changes in the immune environment might be important mechanisms of implantation window shift. The functional enrichment analysis results also suggested that the changes in microbiota had an important role in the changes in endometrial status. The endometrial functionally active microbial profiles were obtained based on previously validated metatranscriptomic analysis pipelines. Combining host gene expression information, immune cell abundance information and functionally active microbial abundance and activity information, we found that Treponema succinifaciens, Fusobacterium sp. oral taxon 203 and other potentially harmful species may over-activate Eicosapentaenoic acid (EPA) biosynthesis Thus, the balance of the immune environment of the endometrium is disrupted, resulting in the shift of the implantation window and the failure of embryo implantation.

Role of ACSL5 in fatty acid metabolism

Free fatty acids (FFAs) are essential energy sources for most body tissues. A fatty acid must be converted to fatty acyl-CoA to oxidize or be incorporated into new lipids. Acyl-CoA synthetase long-chain family member 5 (ACSL5) is localized in the endoplasmic reticulum and mitochondrial outer membrane, where it catalyzes the formation of fatty acyl-CoAs from long-chain fatty acids (C16-C20). Fatty acyl-CoAs are then used in lipid synthesis or β-oxidation mediated pathways. ACSL5 plays a pleiotropic role in lipid metabolism depending on substrate preferences, subcellular localization and tissue specificity. Here, we review the role of ACSL5 in fatty acid metabolism in multiple metabolic tissues, including the liver, small intestine, adipose tissue, and skeletal muscle. Given the increasing number of studies suggesting the role of ACSL5 in glucose and lipid metabolism, we also summarized the effects of ACSL5 on circulating lipids and insulin resistance.

Klotho improves cardiac fibrosis, inflammatory cytokines, ferroptosis, and oxidative stress in mice with myocardial infarction

The anti-aging protein Klotho has been associated with cardiovascular health protection. Nevertheless, the protective mechanism remains unknown. The present study is aimed at exploring the effect of Klotho on cardiac remodeling and its potential mechanism in mice with myocardial infarction (MI). We used left anterior coronary artery descending ligation to develop an MI model for in vivo analyses. In contrast, H9C2 cells and cardiac fibroblasts were used to establish the oxygen-glucose deprivation (OGD) model in in vitro analyses. In vivo and in vitro models were treated with Klotho. Compound C, an AMPK signaling inhibitor, was used to determine whether Klotho's effects are mediated through the AMPK/mTOR signaling pathway. Echocardiography, Masson trichrome staining, immunofluorescence, immunohistochemistry, real-time polymerase chain reaction (RT-PCR), and western blot were used to detect the related indicators. The findings of the in vivo model indicate that Klotho treatment improved the mice's cardiac function, reduced cardiac fibrosis, and attenuated myocardial inflammatory factors, ferroptosis, and oxidative stress. The results of the in vitro model were in line with the findings of in vivo modeling. An AMPK inhibitor, Compound C, reversed all these effects. In conclusion, Klotho potentially improves cardiac remodeling in MI mice by regulating AMPK/mTOR signaling, demonstrating Klotho as an effective MI therapeutic agent.

iTRAQ-based Proteomic Analysis Unveils ACSL4 as a Novel Potential Regulator of Human Endometrial Receptivity

Competent endometrial receptivity is a prerequisite for successful embryo implantation. Identification of novel key molecules involved in endometrial receptivity is essential to better interpret human implantation and improve pregnancy rates in assisted reproduction treatment. Isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomics was performed to profile the proteomes of the prereceptive (luteinizing hormone [LH] + 2, n = 4) and receptive (LH + 7, n = 4) endometrial tissues. A total of 173 differentially expressed proteins (DEPs) between LH + 2 and LH + 7 endometrial samples were identified. Integrated analysis of the proteomic data and published transcriptomic data was performed to identify the concordant DEPs with differential expression at both the messenger RNA and protein levels. Protein-protein interaction (PPI) network analysis was performed on concordant DEPs. We first identified 63 novel concordant DEPs and 5 hub proteins (ACSL4, ACSL5, COL1A1, PTGS1, and PLA2G4F) between LH + 2 and LH + 7 endometrial samples. ACSL4 was predominantly expressed in endometrial epithelial cells and its expression was significantly upregulated by progesterone in the LH + 7 endometrium and significantly downregulated in repeated implantation failure patients. Knockdown of ACSL4 in endometrial epithelial cells induced the downregulation of endometrial receptivity markers (HOXA10, COX2, and LIF) and the significant decrease of implantation rate during in vitro implantation analysis. This study provides the first gel-independent quantitative proteomes of the LH + 2 and LH + 7 human endometrium using iTRAQ technology. The identified concordant DEPs and hub proteins open a new avenue for future studies aimed at elucidating the underlying mechanisms governing endometrial receptivity. ACSL4 was identified as a novel regulatory molecule in the establishment of endometrial receptivity and might play important roles during implantation.

Pulmonary artery embolism: comprehensive transcriptomic analysis in understanding the pathogenic mechanisms of the disease

BACKGROUND

Pulmonary embolism (PE) is a severe disease that usually originates from deep vein thrombosis (DVT) of the lower extremities. This study set out to investigate the changes in the transcriptome of the pulmonary artery (PA) in the course of the PE in the porcine model.

METHODS

The study was performed on 11 male pigs: a thrombus was formed in each right femoral vein in six animals, and then was released to induce PE, the remaining five animals served as a control group. In the experimental animals total RNA was isolated from the PA where the blood clot lodged, and in the control group, from the corresponding PA segments. High-throughput RNA sequencing was used to analyse the global changes in the transcriptome of PA with induced PE (PA-E).

RESULTS

Applied multistep bioinformatics revealed 473 differentially expressed genes (DEGs): 198 upregulated and 275 downregulated. Functional Gene Ontology annotated 347 DEGs into 27 biological processes, 324 to the 11 cellular components and 346 to the 2 molecular functions categories. In the signaling pathway analysis, KEGG 'protein processing in endoplasmic reticulum' was identified for the mRNAs modulated during PE. The same KEGG pathway was also exposed by 8 differentially alternative splicing genes. Within single nucleotide variants, the 61 allele-specific expression variants were localised in the vicinity of the genes that belong to the cellular components of the 'endoplasmic reticulum'. The discovered allele-specific genes were also classified as signatures of the cardiovascular system.

CONCLUSIONS

The findings of this research provide the first thorough investigation of the changes in the gene expression profile of PA affected by an embolus. Evidence from this study suggests that the disturbed homeostasis in the biosynthesis of proteins in the endoplasmic reticulum plays a major role in the pathogenesis of PE.

An update on the therapeutic implications of long-chain acyl-coenzyme A synthetases in nervous system diseases

Long-chain acyl-coenzyme A synthetases (ACSLs) are a family of CoA synthetases that activate fatty acid (FA) with chain lengths of 12-20 carbon atoms by forming the acyl-AMP derivative in an isozyme-specific manner. This family mainly includes five members (ACSL1, ACSL3, ACSL4, ACSL5, and ACSL6), which are thought to have specific and different functions in FA metabolism and oxidative stress of mammals. Accumulating evidence shows that the dysfunction of ACSLs is likely to affect cell proliferation and lead to metabolic diseases in multiple organs and systems through different signaling pathways and molecular mechanisms. Hence, a central theme of this review is to emphasize the therapeutic implications of ACSLs in nervous system disorders.

Bromodomain-containing protein 4 (BRD4) as an epigenetic regulator of fatty acid metabolism genes and ferroptosis

Reprogramming lipid metabolism is considered a fundamental step in tumourigenesis that influences ferroptosis. However, molecular mechanisms between lipid metabolism and ferroptosis remain largely unknown. Results from the drug screening of 464 inhibitors (for 164 targets) applied to ferroptosis cells indicated that 4 inhibitors targeted bromodomain-containing protein 4 (BRD4) significantly inhibiting erastin-induced ferroptosis. Functional studies proved that the loss of BRD4 weakened oxidative catabolism in mitochondria, protecting cells from the excessive accumulation of lipid peroxides. Mechanism research revealed that the transcriptional levels of fatty acid metabolism-related genes (HADH, ACSL1 and ACAA2) participating in the β-oxidation of fatty acids (FAO) and polyunsaturated fatty acids (PUFAs) synthesis depended on the activity of super-enhancers (SEs) formed by BRD4 and HMGB2 in their promoter regions. Conclusively, this study demonstrated that BRD4 was indispensable for fatty acid metabolism based on its epigenetic regulatory mechanisms and affecting erastin-induced ferroptosis, providing a new theoretical reference for understanding the relationship between lipid metabolism and ferroptosis deeply.

Emerging roles of ferroptosis in cardiovascular diseases

The mechanism of cardiovascular diseases (CVDs) is complex and threatens human health. Cardiomyocyte death is an important participant in the pathophysiological basis of CVDs. Ferroptosis is a new type of iron-dependent programmed cell death caused by excessive accumulation of iron-dependent lipid peroxides and reactive oxygen species (ROS) and abnormal iron metabolism. Ferroptosis differs from other known cell death pathways, such as apoptosis, necrosis, necroptosis, autophagy and pyroptosis. Several compounds have been shown to induce or inhibit ferroptosis by regulating related key factors or signalling pathways. Recent studies have confirmed that ferroptosis is associated with the development of diverse CVDs and may be a potential therapeutic drug target for CVDs. In this review, we summarize the characteristics and related mechanisms of ferroptosis and focus on its role in CVDs, with the goal of inspiring novel treatment strategies.

CD8+ T cells and fatty acids orchestrate tumor ferroptosis and immunity via ACSL4

Tumor cell intrinsic ferroptosis-initiating mechanisms are unknown. Here, we discover that T cell-derived interferon (IFN)γ in combination with arachidonic acid (AA) induces immunogenic tumor ferroptosis, serving as a mode of action for CD8+ T cell (CTL)-mediated tumor killing. Mechanistically, IFNγ stimulates ACSL4 and alters tumor cell lipid pattern, thereby increasing incorporations of AA into C16 and C18 acyl chain-containing phospholipids. Palmitoleic acid and oleic acid, two common C16 and C18 fatty acids in blood, promote ACSL4-dependent tumor ferroptosis induced by IFNγ plus AA. Moreover, tumor ACSL4 deficiency accelerates tumor progression. Low-dose AA enhances tumor ferroptosis and elevates spontaneous and immune checkpoint blockade (ICB)-induced anti-tumor immunity. Clinically, tumor ACSL4 correlates with T cell signatures and improved survival in ICB-treated cancer patients. Thus, IFNγ signaling paired with selective fatty acids is a natural tumor ferroptosis-promoting mechanism and a mode of action of CTLs. Targeting the ACSL4 pathway is a potential anti-cancer approach.

Photoaffinity-Based Chemical Proteomics Reveals 7-Oxocallitrisic Acid Targets CPT1A to Trigger Lipogenesis Inhibition

One of the natural terpenoids isolated from Resina Commiphora, 7-oxocallitrisic acid (7-OCA), has lipid metabolism regulatory activity. To uncover its lipogenesis inhibition mechanism, we developed a photoaffinity and clickable probe based on the 7-OCA scaffold and performed chemical proteomics to profile its potential cellular targets. It was found that 7-OCA could directly interact with carnitine palmitoyl transferase 1A (CPT1A) to promote its activity to reduce lipid accumulation. The present work reveals our understanding of the mode of lipid mebabolism regulation by abietic acids and provides new clues for antiobesity drug development with CPT1A as a main target.

Myeloid-Specific Deficiency of Long-Chain Acyl CoA Synthetase 4 Reduces Inflammation by Remodeling Phospholipids and Reducing Production of Arachidonic Acid-Derived Proinflammatory Lipid Mediators

In response to infection or tissue damage, resident peritoneal macrophages (rpMACs) produce inflammatory lipid mediators from the polyunsaturated fatty acid (PUFA), arachidonic acid (AA). Long-chain acyl-CoA synthetase 4 (ACSL4) catalyzes the covalent addition of a CoA moiety to fatty acids, with a strong preference for AA and other PUFAs containing three or more double bonds. PUFA-CoA can be incorporated into phospholipids, which is the source of PUFA for lipid mediator synthesis. In this study, we demonstrated that deficiency of Acsl4 in mouse rpMACs resulted in a significant reduction of AA incorporated into all phospholipid classes and a reciprocal increase in incorporation of oleic acid and linoleic acid. After stimulation with opsonized zymosan (opZym), a diverse array of AA-derived lipid mediators, including leukotrienes, PGs, hydroxyeicosatetraenoic acids, and lipoxins, were produced and were significantly reduced in Acsl4-deficient rpMACs. The Acsl4-deficient rpMACs stimulated with opZym also demonstrated an acute reduction in mRNA expression of the inflammatory cytokines, Il6, Ccl2, Nos2, and Ccl5 When Acsl4-deficient rpMACs were incubated in vitro with the TLR4 agonist, LPS, the levels of leukotriene B4 and PGE2 were also significantly decreased. In LPS-induced peritonitis, mice with myeloid-specific Acsl4 deficiency had a significant reduction in leukotriene B4 and PGE2 levels in peritoneal exudates, which was coupled with reduced infiltration of neutrophils in the peritoneal cavity as compared with wild-type mice. Our data demonstrate that chronic deficiency of Acsl4 in rpMACs reduces the incorporation of AA into phospholipids, which reduces lipid mediator synthesis and inflammation.