FAT SIGNALS--lipases and lipolysis in lipid metabolism and signaling

Effects of alpelisib treatment on murine Pten-deficient lipomas

 Phosphatase and tensin homolog (PTEN) hamartoma tumour syndrome (PHTS) is a rare disorder caused by germline mutations in the tumour suppressor gene PTEN, a key negative regulator of phosphatidylinositol 3-kinase (PI3K)/AKT signalling. Children with PHTS often develop lipomas, for which only surgical resection is available as treatment. We investigated the effects of the selective PI3K-inhibitor alpelisib on Pten-deficient lipomas. After incubation with alpelisib or the non-selective PI3K inhibitor wortmannin, we analysed histology, gene expression, and Pi3k pathway in lipoma and control epididymal adipose tissue (epiWAT). Alpelisib increased adipocyte area in lipomas compared to epiWAT. Baseline gene expression showed higher levels of markers for proliferation (Pcna), fibrosis (Tgfb1), and adipogenesis (Pparg) in lipomas, while hormone-sensitive lipase expression was lower than in epiWAT. Following alpelisib incubation, target genes of Pi3k signalling and extracellular matrix factors were reduced. We confirmed Pi3k inhibition through detecting decreased Akt levels compared to control treatment. Human lipoma samples treated with alpelisib showed variable lipolysis responses, suggesting variability in therapeutic outcomes. We established an ex vivo model to study alpelisib effects on Pten-deficient lipomas. These results underscore the therapeutic potential of targeted PI3K inhibition in the treatment of PHTS-associated lipomas, particularly in cases that are inoperable.

Increased accumulation of fatty acids in engineered Saccharomyces cerevisiae by co-overexpression of interorganelle tethering protein and lipases

Fatty acids (FAs) and their derivatives are versatile chemicals widely used in various industries. Synthetic biology, using microbial cell factories, emerges as a promising alternative technology for FA production. To enhance the production capacity of these microbial chassis, additional engineering strategies are imperative. Based on the comparison of the morphological changes of lipid droplets (LDs) between oleaginous and non-oleaginous yeasts, we developed a new engineering strategy to increase the accumulation of FAs in Saccharomyces cerevisiae through manipulation of regulation factor and lipases related to LD. The increased biogenesis of LDs, achieved by overexpressing the interorganelle tethering protein Mdm1, coupled with the accelerated degradation of LDs through upregulated lipases, resulted in a 10.70-fold increase in total FAs production. Co-overexpression of Mdm1 and selected lipases significantly improved the biosynthesis of FAs and linoleic acid in the engineered S. cerevisiae. The efficient LD-based metabolic engineering strategy presented in this study holds the potential to advance the high-level production of FAs and their derivatives in microbial cell factories.

TSH-stimulated hepatocyte exosomes modulate liver-adipose triglyceride accumulation via the TGF-β1/ATGL axis in mice

Subclinical hypothyroidism (SCH) contributes to obesity, with the liver acting as a crucial metabolic regulator. Thyroid-stimulating hormone (TSH) affects systemic lipid balance, potentially linking SCH to obesity. While the direct impact of TSH on hepatic lipid metabolism has been extensively documented, its role in modulating lipid dynamics in peripheral organs through liver-mediated pathways remains insufficiently understood. This study identifies TSH-stimulated hepatocyte-derived exosomes (exosomesTSH) as key mediators in liver-adipose communication, promoting triglyceride accumulation in adipocytes via the transforming growth factor-beta 1 (TGF-β1)/adipose triglyceride lipase (ATGL) axis. ExosomesTSH enhance lipid storage in adipocytes, significantly increasing triglyceride content and lipid droplet formation while reducing lipolysis, effects that are dependent on TSH receptor (TSHR) activation in hepatocytes. In vivo, exosomesTSH induce weight gain and adipose tissue expansion, impairing glucose metabolism in both chow- and high-fat diet-fed mice. Mechanistically, exosomesTSH upregulate TGF-β1 and downregulate ATGL in adipocytes, establishing the TGF-β1/ATGL pathway as essential for exosome-mediated lipid accumulation. Further, miR-139-5p is identified as a modulator of TGF-β1 expression within this pathway, with overexpression of miR-139-5p alleviating exosomesTSH-induced lipid accumulation in adipocytes. This study elucidates a novel miR-139-5p-dependent mechanism through which TSH modulates lipid metabolism via liver-derived exosomes, highlighting the pivotal role of miR-139-5p in linking SCH to adipose lipid accumulation through the TGF-β1/ATGL signaling axis.

Shouhui Tongbian Capsule ameliorates obesity by enhancing energy consumption and promoting lipolysis via cAMP-PKA pathway

BACKGROUND

The prevalence of obesity and its associated diseases has sharply increased, becoming a global health issue. White adipose tissue (WAT), responsible for lipid storage via hyperplasia and hypertrophy, and brown adipose tissue (BAT), which facilitates energy dissipation, have increasingly been recognized as critical regulators of weight loss. Shouhui Tongbian Capsule (SHTB) has traditionally been used for detoxification, weight loss, and lipid reduction, and clinical evidence supports its use for relieving constipation. In traditional Chinese medicine (TCM), "dissipating turbidity" is seen as a shared approach to treating both constipation and obesity. Our evidence suggests that SHTB improves obesity and metabolic disorders, but the underlying mechanisms remain unclear.

PURPOSE

This study aimed to evaluate the pharmacological effects of SHTB on obesity and to explore the underlying mechanisms involved.

METHODS

Obese mice induced by a high-fat diet were treated with SHTB, and effects on body weight, adipose tissue, and metabolism were assessed. Active ingredients were identified through UPLC-MS, while metabolomics and RNA sequencing were performed to explore the mechanisms of SHTB in obesity, and molecular biology techniques validated its effects on energy consumption and lipolysis in adipose tissue. Finally, rescue experiments in vivo and in vitro confirmed the proposed mechanisms.

RESULTS

SHTB significantly reduced body weight, body fat percentage, and WAT mass while increasing BAT weight, and enhancing energy expenditure. Metabolomics and RNA sequencing indicated activation of the G-protein coupled receptor signaling and cAMP-PKA pathway, leading to increased lipolysis in WAT and enhanced thermogenesis in BAT. H89, a PKA agonist, counteracted these effects, supporting the involvement of cAMP-PKA signaling.

CONCLUSION

SHTB may prevent obesity by promoting lipolysis and enhancing BAT thermogenesis via the cAMP-PKA pathway, offering a potential therapeutic approach for obesity management.

Oncogenic KRAS Promotes Ferroptosis in Pancreatic Cancer Through Regulation of the Fosl1-Tfrc Axis

ABSTRACT

Mutant KRAS activation occurs in most of pancreatic ductal adenocarcinoma (PDAC), which induce the sensitivity to ferroptosis of PDAC cells, but the underlying mechanism is still poorly understood. Here, we show how KRAS acts in signaling to activate transcription factor FOSL1, which promotes the expression of the iron uptake receptor TFRC. In PDAC cells, repression of TFRC by KRAS/FOSL1 signaling inhibited intracellular iron levels, thereby restricting the occurrence of ferroptosis. Furthermore, the KRAS/FOSL1/TFRC axis can make the PDAC cells vulnerable to alteration of the iron level in the tumor microenvironment. Our study highlights a pivotal mechanism of PDAC ferroptosis through iron metabolism and supports a new therapeutic strategy for PDAC with superior potential.

Protocatechuic Acid Suppresses Lipid Uptake and Synthesis through the PPARγ Pathway in High-Fat Diet-Induced NAFLD Mice

Nonalcoholic fatty liver disease (NAFLD) has become one of the most concerning health problems in the world. Dietary intervention is an effective way to prevent and improve NAFLD. As one of the main metabolites of anthocyanins, protocatechuic acid (PCA) exhibited strong activity to improve NAFLD, but the specific mechanism remains unclear. Currently, proteomics has been used to identify that PCA treatment could significantly influence the expression of 224 proteins, including 89 downregulated proteins and 135 upregulated proteins. KEGG analysis showed that PCA obviously inhibited the peroxisome proliferator-activated receptor (PPAR) signaling pathway. Immunofluorescence and Western blot analyses further confirmed that PCA repressed the protein expression of PPARγ and subsequently inhibited the expression of free fatty acid (FFA) uptake proteins (CD36 and FABP2) and FFA synthesis proteins (ACC and FASN), respectively. These effects of PCA contributed to the inhibitory activity of excessive lipid accumulation in the liver. Our results highlighted that PCA could effectively alleviate high-fat diet-induced (HFD) NAFLD by inhibiting lipid absorption and synthesis through the PPARγ signaling pathway.

Study on the mechanism of solasonine inhibiting the proliferation of oral squamous cell carcinoma based on lipidomics

Solasonine (SS) has been shown to inhibit the proliferation of various malignant tumors, though its effects on lipid metabolism in tumor cells are less understood. This study investigated SS's anti-tumor mechanism in oral squamous cell carcinoma (OSCC) using lipidomics, cell, and animal models. SS inhibited the growth of CAL27 and WSU-HN30 cells and reduced tumor volume in mice. Lipidomic analysis revealed an increase in diglyceride (DG) and a decrease in triglyceride (TG) levels, alongside a reduction in diacylglycerol acyltransferase 1 (DGAT1), key to TG synthesis. SS also induced reactive oxygen species (ROS) production and mitochondrial damage. Molecular docking confirmed SS's interaction with DGAT1, suggesting it prevents DG to TG conversion, inhibiting OSCC proliferation.

Red fluorescent AIE bioprobes with a large Stokes shift for droplet-specific imaging and fatty liver diagnosis

Lipid droplets (LDs) as spherical dynamic subcellular organelles, play an important role in various cellular functions such as protein degradation, lipid metabolism, energy storage, signal transduction, and membrane formation. Abnormal function of LDs will lead to a series of diseases and hence monitoring the status of LDs is particularly important. In this study, we synthesized a water-insoluble red fluorescent emitting small molecule fluorescent probe (TPE-TCF), which exhibited aggregation-induced emission (AIE) properties and enabled highly selective real-time imaging of LDs (Pearson's R value was 0.90). More interestingly, this probe was able to track the dynamic processes of LDs in living cells, including lipophagy, and monitor fatty liver disease in mice. Therefore, TPE-TCF with red fluorescence emission, good biocompatibility, large Stokes shift, AIE properties, LDs imaging, and fatty liver recognition capabilities can be practically used in more LDs-related diseases.

The Role of Erythropoietin in Metabolic Regulation

Erythropoietin (EPO) is a key regulator of erythrocyte production, promoting erythroid progenitor cell survival, division, and differentiation in the fetal liver and adult bone marrow. Mice lacking EPO or its receptor (EPOR) die in utero due to severe anemia. Beyond hematopoiesis, EPO influences non-hematopoietic tissues, including glucose and fat metabolism in adipose tissue, skeletal muscle, and the liver. EPO is used to treat anemia associated with chronic kidney disease clinically and plays a role in maintaining metabolic homeostasis and regulating fat mass. EPO enhances lipolysis while inhibiting lipogenic gene expression in white adipose tissue, brown adipose tissue, skeletal muscle, and the liver, acting through the EPO-EPOR-RUNX1 axis. The non-erythroid EPOR agonist ARA290 also improves diet-induced obesity and glucose tolerance providing evidence for EPO regulation of fat metabolism independent of EPO stimulated erythropoiesis. Therefore, in addition to the primary role of EPO to stimulate erythropoiesis, EPO contributes significantly to EPOR-dependent whole-body metabolic response.

Advances in Oral Biomacromolecule Therapies for Metabolic Diseases

Metabolic diseases like obesity and diabetes are on the rise, and therapies with biomacromolecules (such as proteins, peptides, antibodies, and oligonucleotides) play a crucial role in their treatment. However, these drugs are traditionally injected. For patients with chronic diseases (e.g., metabolic diseases), long-term injections are accompanied by inconvenience and low compliance. Oral administration is preferred, but the delivery of biomacromolecules is challenging due to gastrointestinal barriers. In this article, we introduce the available biomacromolecule drugs for the treatment of metabolic diseases. The gastrointestinal barriers to oral drug delivery and strategies to overcome these barriers are also explored. We then discuss strategies for alleviating metabolic defects, including glucose metabolism, lipid metabolism, and energy metabolism, with oral biomacromolecules such as insulin, glucagon-like peptide-1 receptor agonists, proprotein convertase subtilisin/kexin type 9 inhibitors, fibroblast growth factor 21 analogues, and peptide YY analogues.

Lipid dysregulation in triple negative breast cancer: Insights from mass spectrometry-based approaches

Triple negative breast cancer (TNBC) has the worst prognosis among breast cancers due to its aggressive nature and the absence of targeted treatments. Development of novel anti-cancer drugs for TNBC faces challenges stemming from its heterogeneity and high potential for metastasis. Metabolomics can be a useful technology in finding novel therapeutic targets and probing the heterogeneity of TNBC. Metabolomics has been enabled by advancements in mass spectrometry (MS)-based platforms that facilitated comprehensive profiling of TNBC metabolism. This review provides an overview of metabolomic changes in TNBC with emphasis on lipid alterations, and describes the key MS analytical techniques, providing the necessary background for examining the role of lipids in TNBC development.

Alternate-day fasting enhanced weight loss and metabolic benefits over pair-fed calorie restriction in obese mice

OBJECTIVE

Both alternate-day fasting (ADF) and calorie restriction (CR) are effective weight loss strategies. However, most individuals find it difficult to adhere to CR. Furthermore, CR can induce an excessive loss of not only fat but also muscle mass. This study aimed to compare the effects of ADF and pair-feeding (PF) CR on metabolic pathways underlying obesity in mice with high-fat diet (HFD)-induced obesity.

METHODS

Male C57BL/6N Tac mice (n = 10 per group) were fed an HFD for 8 weeks to establish a diet-induced obesity model. Mice were then continued on the HFD with either alternate-day access to food or PF for the next 8 weeks. We measured body weight, adiposity, plasma biomarkers, and molecular mechanisms involving lipolysis and autophagy.

RESULTS

Both ADF and PF resulted in comparable weight and fat loss. Compared with PF, ADF showed a significant reduction in liver weight and hepatic triglyceride levels. ADF significantly increased plasma ketone body levels and white adipose tissue lipolysis. Compared with PF, ADF tended to activate autophagy elongation and autophagosome formation, which were insignificant.

CONCLUSIONS

These findings indicated that ADF is a promising intervention for metabolic diseases, potentially due to its superior efficacy in promoting ketogenesis and lipolysis compared with PF.

Complex Role of Circulating Triglycerides in Breast Cancer Onset and Survival: Insights From Two-Sample Mendelian Randomization Study

BACKGROUND

Reducing the incidence of breast cancer and improving its prognosis have become significant challenges for the global public health sector. We aimed to investigate the role of circulating triglycerides in the occurrence and survival of patients with breast cancer, while focusing on the possible differential effects by molecular subtypes of breast cancer.

METHODS

We used a Mendelian randomization approach to analyze publicly accessible genome-wide association study data, including triglyceride levels, breast cancer risk, and survival prognosis. We performed a two-sample causality inference analysis using the inverse-variance weighted method. We used both Mendelian randomization-Egger regression and weighted median methods for model verification. Heterogeneity was evaluated using Cochran's Q test, and sensitivity analyses were performed using the leave-one-out method, Mendelian randomization-Egger intercept test, and Mendelian Randomization Pleiotropy RESidual Sum and Outlier test.

RESULTS

The results revealed a negative causal relationship between triglyceride levels and overall breast cancer risk (odds ratio [OR] = 0.94, confidence interval [CI] = 0.89-0.99, p = 0.011), luminal A breast cancer risk (OR = 0.93, CI = 0.87-0.99, p = 0.014), and human epidermal growth factor receptor 2 (HER2)-enriched breast cancer risk (OR = 0.84, CI = 0.73-0.96, p = 0.010). However, no statistically significant correlations were observed for the luminal B, luminal B HER2-negative, and triple-negative subtypes. Furthermore, triglyceride levels showed a positive causal relationship with the risk of survival prognosis in patients with estrogen receptor-negative breast cancer (OR = 1.33, CI = 1.00-1.76, p = 0.047). However, no statistically significant impact was observed on the survival of patients with overall breast cancer or patients with estrogen receptor-positive, HER2-positive, and HER2-negative breast cancer.

CONCLUSIONS

The potentially complex role of circulating triglycerides in the incidence and survival of patients with breast cancer provides a new perspective on the heterogeneity of the effects of triglycerides on breast cancer, thereby promoting the development of precise medical strategies. Moreover, our findings contribute to an increased understanding of overall health among patients and clinicians alike.

Exercise-induced methylation of the Serhl2 promoter and implication for lipid metabolism in rat skeletal muscle

OBJECTIVES

Environmental factors such as physical activity induce epigenetic modifications, with exercise-responsive DNA methylation changes occurring in skeletal muscle. To determine the skeletal muscle DNA methylation signature of endurance swim training, we used whole-genome methylated DNA immunoprecipitation (MeDIP) sequencing.

METHODS

We utilized endurance-trained rats, cultured L6 myotubes, and human skeletal muscle cells, employing MeDIP sequencing, gene silencing, and palmitate oxidation assays. Additional methods included promoter luciferase assays, fluorescence microscopy, and RNA/DNA analysis to investigate exercise-induced molecular changes.

RESULTS

Gene set enrichment analysis (GSEA) of differentially methylated promoter regions identified an enrichment of four gene sets, including those linked to lipid metabolic processes, with hypermethylated or hypomethylated promoter regions in skeletal muscle of exercise-trained rats. Bisulfite sequencing confirmed hypomethylation of CpGs in the Serhl2 (Serine Hydrolase Like 2) transcription start site in exercise-trained rats. Serhl2 gene expression was upregulated in both exercise-trained rats and an "exercise-in-a-dish" model of L6 myotubes subjected to electrical pulse stimulation (EPS). Serhl2 promoter activity was regulated by methylation and EPS. A Nr4a binding motif in the Serhl2 promoter, when deleted, reduced promoter activity and sensitivity to methylation in L6 myotubes. Silencing Serhl2 in L6 myotubes reduced intracellular lipid oxidation and triacylglycerol synthesis in response to EPS.

CONCLUSIONS

Exercise-training enhances intracellular lipid metabolism and phenotypic changes in skeletal muscle through epigenomic modifications on Serhl2. Hypomethylation of the Serhl2 promoter influences Nr4a transcription factor binding, promoter activity, and gene expression, linking exercise-induced epigenomic regulation of Serhl2 to lipid oxidation and triacylglycerol synthesis.

A Novel PNPLA2 Variant in a Female Patient with Neutral Lipid Storage Disease with Myopathy and Hypogonadotropic Hypogonadism

Background

Neutral lipid storage disease with myopathy (NLSDM) is a rare autosomal recessive disorder characterized by aberrant triacylglycerol metabolism due to mutations in the patatin-like phospholipase domain-containing 2 (PNPLA2) gene.

Case Presentation

This report presents a case study of a 14-year-old female patient exhibiting symptoms of NLSDM, including recurrent abdominal pain, fatigue, leg pain, and hepatosteatosis. Diagnostic investigations revealed elevated creatinine kinase levels, myopathic findings on electromyography, magnetic resonance imaging findings showing gluteal involvement and Jordans' bodies on peripheral smear. Clinical exome panel showed homozygous of PNPLA2 c.496G>C p.Asp166His (NM_020376.4) variant. The clinical manifestations, diagnostic challenges, and implications of this novel variant are discussed in the context of current literature. Hypogonadotropic hypogonadism was confirmed in this patient after eliminating possible underlying causes. This was a novel manifestation, and hormone replacement therapy was planned.

Conclusion

This case underscores the significance of genetic testing in elucidating the molecular basis of NLSDM and emphasizes the necessity of comprehensive clinical evaluation for accurate diagnosis and management.

Effect of Cordyceps militaris extract containing cordycepin on the adipogenesis and lipolysis of adipocytes

Obesity, a global health concern, results from an energy imbalance leading to lipid accumulation. In the present study, Cordyceps militaris extract (CM) and its primary component, cordycepin, were investigated to characterize their potential effects on adipogenesis and lipolysis. Treatment with CM or cordycepin reduced lipid droplets and increased hormone-sensitive lipase activation in 3T3-L1 cells. In a diabetic obese mouse model, CM and cordycepin lowered serum low-density lipoprotein/very low-density lipoprotein levels and reduced oxidative stress and cell senescence markers. Thus, cordycepin inhibits preadipocyte differentiation and promotes lipolysis, which may serve as a novel obesity treatment. Further studies, including clinical trials, are required to validate the clinical potential of cordycepin.

Classical prescription Daqinjiao decoction inhibit cerebral ischemia/reperfusion induced necroptosis and ferroptosis through multiple mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

The Daqinjiao decoction (DQJT), a classical prescription, has been utilized for millennia in stroke management, yet its underlying mechanisms remained obscure.

AIM OF THE STUDY

The aim of this study was to elucidate the mechanisms through which DQJT mitigates cerebral ischemia/reperfusion injury (CI/RI).

MATERIALS AND METHODS

The quantification of DQJT's primary components were performed by HPLC. Pharmacological assessments were then conducted to ascertain DQJT's efficacy in a Middle Cerebral Artery Occlusion/Reperfusion (MCAO/R) model. Following this, untargeted metabolomics, lipidomics and network pharmacology analyses were undertaken to unveil potential mechanisms, which were subsequently validated. UPLC-Q-TOF/MS was utilized to detect DQJT-derived chemicals in brain tissue, and molecular docking techniques were employed to investigate the bioactive compounds.

RESULTS

DQJT treatment reduced brain damage induced by MCAO/R, as evidenced by decreased infarct sizes, enhanced behavioral function scores, and diminished neuronal damages. Untargeted metabolomics and lipidomics revealed that DQJT improved metabolism of unsaturated fatty acids. According to network pharmacology, lipid metabolism, cAMP signaling pathway and toll-like receptor signaling pathway pathways were notably affected, with HSP90AA1, TLR4, and PKA identified as potential targets of DQJT. Immunofluorescence and Western blot analyses further demonstrated that DQJT counteracted necroptosis and ferroptosis by inhibiting the HSP90AA1 and TLR4 pathways and enhancing the PKA pathway. Molecular docking results supported that the possible pharmacodynamic substances of DQJT in protecting against CI/RI.

CONCLUSION

This research established that DQJT attenuates brain injury induced by MCAO/R through the modulation of necroptosis and ferroptosis via pathways including HSP90AA1, TLR4, and PKA. It shed light on the potential mechanisms and effective constituents of DQJT in stroke treatment, paving the way for further exploration of this ancient formula.

The measurement, regulation and biological activity of FAHFAs

Fatty acid esters of hydroxy fatty acids (FAHFAs) are bioactive lipids that are positively correlated with metabolic health in humans and mice. Since their discovery, understanding the role and regulation of FAHFAs has been a prime focus of research into these lipids. In this Review, we describe how FAHFAs are quantitatively measured from biological samples. We then highlight advances in elucidating the genes responsible for the regulation of endogenous FAHFA levels through the degradation, biosynthesis and storage of FAHFAs. We conclude by presenting several examples of antidiabetic and immunomodulatory effects of FAHFAs in cells and in vivo, including their ability to protect against type 1 diabetes. These FAHFA topics are interconnected by their reliance on chemistry and chemical biology to enlighten this frontier of lipid biology, offering new perspectives on metabolic health and potential therapeutic interventions.

Lipid Metabolic Heterogeneity during Early Embryogenesis Revealed by Hyper-3D Stimulated Raman Imaging

Studying embryogenesis is fundamental to understanding developmental biology and reproductive medicine. Its process requires precise spatiotemporal regulations in which lipid metabolism plays a crucial role. However, the spatial dynamics of lipid species at the subcellular level remains obscure due to technical limitations. To address this challenge, we developed a hyperspectral 3D imaging and analysis method based on stimulated Raman scattering microscopy (hyper-3D SRS) to quantitatively assess lipid profiles in individual embryos through submicrometer resolution (x-y), 3D optical sectioning (z), and chemical bond-selective (Ω) imaging. Using hyper-3D SRS, individual lipid droplets (LDs) in single cells were identified and quantified. Our findings revealed that the LD profiles within a single embryo are not uniform, even as early as the 2-cell stage. Notably, we also discovered a dynamic relationship between the LD size and unsaturation degree as embryos develop, indicating diverse lipid metabolism during early development. Furthermore, abnormal LDs were observed in oocytes of a progeria mouse model, suggesting that LDs could serve as a potential biomarker for assessing oocyte/embryo quality. Overall, our results highlight the potential of hyper-3D SRS as a noninvasive method for studying lipid content, composition, and subcellular distribution in embryos. This technique provides valuable insights into lipid metabolism during embryonic development and has the potential for clinical applications in evaluating oocyte/embryo quality.

PEDF Overexpression Ameliorates Cardiac Lipotoxicity in Diabetic Cardiomyopathy via Regulation of Energy Metabolism

Background

Early alterations in cardiac energy metabolism and lipotoxicity are crucial factors in the pathogenesis and progression of diabetic cardiomyopathy (DCM). The excessive accumulation of lipid metabolic intermediates within the myocardium can lead to increased production of reactive oxygen species (ROS) and promote apoptosis. Pigment epithelium-derived factor (PEDF) has been shown to regulate cardiac energy metabolism; however, its role in modulating energy metabolism, ROS generation, and apoptosis in the context of DCM requires further investigation.

Methods

PEDF was overexpressed in db/db mice via tail vein injection of adeno-associated virus 9(AAV9)-PEDF. At week 24, assessments were conducted on cardiac hypertrophy, fibrosis, cardiac function, and alterations in energy metabolism. Additionally, H9c2 cells were transfected with a PEDF plasmid and cultured under HG+PA conditions (33 mm glucose + 250 μM palmitic acid) for 24 hours. Subsequent analyses focused on changes in energy metabolism, ROS levels, and apoptosis.

Results

At 24 weeks, db/db mice exhibited hallmark features of DCM, including hyperglycemia, hyperlipidemia, cardiac hypertrophy, fibrosis, and diastolic dysfunction. Overexpression of PEDF reversed cardiac remodeling in these mice. In both db/db mice and HG+PA-treated H9c2 cells, PEDF overexpression modulated cardiac energy metabolism, mitigated lipotoxicity, and promoted the expression of adipose triglyceride lipase(ATGL) and glucose transporter type 4(Glut4) while inhibiting the expression of peroxisome proliferator-activated receptor alpha (PPARα), carnitine palmitoyltransferase 1 alpha (CPT1α), and scavenger receptor B2 (CD36). Additionally, PEDF overexpression reduced ROS generation and apoptosis in db/db mice myocardium and HG+PA-treated h9c2 cells.

Conclusion

PEDF can effectively prevent cardiac hypertrophy, fibrosis remodeling, and the deterioration of diastolic dysfunction in DCM by modulating cardiac energy metabolism and mitigating ROS production and apoptosis induced by lipotoxicity.

Genetic association of lipid-lowering drug target genes with pancreatic cancer: a Mendelian randomization study

Previous studies have found that dyslipidemia is a risk factor for pancreatic cancer (PC), and that lipid-lowering drugs may reduce the risk of PC. However, it is not clear whether dyslipidemia causes PC. The Mendelian randomization (MR) study aimed to investigate the causal role of lipid traits in pancreatic cancer and to assess the potential impact of lipid-lowering drug targets on pancreatic cancer. Genetic variants associated with lipid traits and variants of genes encoding lipid-lowering drug targets were extracted from the Global Lipids Genetics Consortium genome-wide association study (GWAS). Summary statistics for PC were obtained from an independent GWAS datasets. Colocalization analyses were performed to validate the robustness of the results. No significant effect of lipid-lowering drug targets on PC risk was found. Genetic mimicry of lipoprotein lipase (LPL) was potentially associated with PC risks. Significant MR associations were observed in the discovery dataset (OR 1.64 [95% CI 1.24-2.16], p = 4.48*10-4) with PC in one dataset. However, the finding was not verified in the replication dataset. Our findings do not support dyslipidemia as a causal factor for PC. Among lipid-lowering drug targets, LPL is the potential drug target in PC.

Optimized Scaffold-Free Human 3D Adipose Tissue Organoid Culture for Obesity and Disease Modeling

Obesity and type 2 diabetes (T2D) are strongly linked to abnormal adipocyte metabolism and adipose tissue (AT) dysfunction. However, existing adipose tissue models have limitations, particularly in the stable culture of fat cells that maintain physiologically relevant phenotypes, hindering a deeper understanding of adipocyte biology and the molecular mechanisms behind differentiation. Current model systems fail to fully replicate in vivo metabolism, posing challenges in adipose research. Three-dimensional (3D) AT organoids, although promising, present significant handling challenges during long-term culture. As adipocytes mature and accumulate fat, they develop organotypic characteristics, increasing the buoyancy effect, which causes the organoids to oscillate, complicating culture manipulation and rendering multiple handling steps difficult. Due to these challenges, most adipose spheroid models are scaffold-based, despite many cell types' ability to secrete extracellular matrix (ECM) components and self-assemble into aggregates. Scaffold-free 3D organoids have been less explored. To address the shortage of affordable and reliable AT models, we utilized magnetic bioprinting technology to develop a human-derived 3D model of adipose tissue. This system incorporates a magnetic holder that restrains organoids, preventing them from floating and minimizing the risk of loss during manipulation. This study outlines a protocol for generating in vitro AT-derived organoid using 3D magnetic bioprinting, with a focus on manufacturing, culturing, and assessing the morpho-functional characteristics of late-stage AT organoids. Magnetic bioprinting allows for the replication of tissue structure and function in vitro without the risk of organoid loss, making it an ideal method for high-throughput AT organoid culture. Additionally, the combination of 3D scaffold-free manufacturing with in vitro disease modeling offers a valuable tool for discovering treatments for metabolic diseases such as obesity and T2D.

Citrate: a key signalling molecule and therapeutic target for bone remodeling disorder

Bone remodeling is a continuous cyclic process that maintains and regulates bone structure and strength. The disturbance of bone remodeling leads to a series of bone metabolic diseases. Recent studies have shown that citrate, an intermediate metabolite of the tricarboxylic acid (TCA) cycle, plays an important role in bone remodeling. But the exact mechanism is still unclear. In this study, we focused on the systemic regulatory mechanism of citrate on bone remodeling, and found that citrate is involved in bone remodeling in multiple ways. The participation of citrate in oxidative phosphorylation (OXPHOS) facilitates the generation of ATP, thereby providing substantial energy for bone formation and resorption. Osteoclast-mediated bone resorption releases citrate from bone mineral salts, which is subsequently released as an energy source to activate the osteogenic differentiation of stem cells. Finally, the differentiated osteoblasts secrete into the bone matrix and participate in bone mineral salts formation. As a substrate of histone acetylation, citrate regulates the expression of genes related to bone formation and bone reabsorption. Citrate is also a key intermediate in the metabolism and synthesis of glucose, fatty acids and amino acids, which are three major nutrients in the organism. Citrate can also be used as a biomarker to monitor bone mass transformation and plays an important role in the diagnosis and therapeutic evaluation of bone remodeling disorders. Citrate imbalance due to citrate transporter could result in the supression of osteoblast/OC function through histone acetylation, thereby contributing to disorders in bone remodeling. Therefore, designing drugs targeting citrate-related proteins to regulate bone citrate content provides a new direction for the drug treatment of diseases related to bone remodeling disorders.

Dual role of triglyceride structures facilitates anti-tumor drug delivery: Both as a self-assembling module and a responsive module

Small molecule prodrugs self-assembled nano-delivery systems with tumor responsive linkages are emerging as an effective platform. However, the heterogeneity of tumor microenvironment may limit the anti-tumor effect of prodrug nanomedicines with a single response module. Here, we chose disulfide bond as the response module and branched chain alcohol as the self-assembly modification module to construct a single-responsive prodrug. We also constructed a double-responsive paclitaxel prodrug combining triglyceride and disulfide bond, taking into account of the highly expressed lipase and glutathione levels in tumor cells. The results showed that the anti-tumor effect of single-responsive branched chain alcohol modified prodrug nanoparticles was inferior to triglyceride prodrug nanoparticles with dual response modules. The triglyceride structure can not only serve as a self-assembly modification module, but also serve as a response module for intelligent drug release in tumor. Such dual roles will facilitate the efficient delivery of small molecule self-assembled prodrugs to tumor sites.

Lipid droplets in central nervous system and functional profiles of brain cells containing lipid droplets in various diseases

Lipid droplets (LDs), serving as the convergence point of energy metabolism and multiple signaling pathways, have garnered increasing attention in recent years. Different cell types within the central nervous system (CNS) can regulate energy metabolism to generate or degrade LDs in response to diverse pathological stimuli. This article provides a comprehensive review on the composition of LDs in CNS, their generation and degradation processes, their interaction mechanisms with mitochondria, the distribution among different cell types, and the roles played by these cells-particularly microglia and astrocytes-in various prevalent neurological disorders. Additionally, we also emphasize the paradoxical role of LDs in post-cerebral ischemia inflammation and explore potential underlying mechanisms, aiming to identify novel therapeutic targets for this disease.

Targeting the initiator to activate both ferroptosis and cuproptosis for breast cancer treatment: progress and possibility for clinical application

Breast cancer is the most commonly diagnosed cancer worldwide. Metal metabolism is pivotal for regulating cell fate and drug sensitivity in breast cancer. Iron and copper are essential metal ions critical for maintaining cellular function. The accumulation of iron and copper ions triggers distinct cell death pathways, known as ferroptosis and cuproptosis, respectively. Ferroptosis is characterized by iron-dependent lipid peroxidation, while cuproptosis involves copper-induced oxidative stress. They are increasingly recognized as promising targets for the development of anticancer drugs. Recently, compelling evidence demonstrated that the interplay between ferroptosis and cuproptosis plays a crucial role in regulating breast cancer progression. This review elucidates the converging pathways of ferroptosis and cuproptosis in breast cancer. Moreover, we examined the value of genes associated with ferroptosis and cuproptosis in the clinical diagnosis and treatment of breast cancer, mainly outlining the potential for a co-targeting approach. Lastly, we delve into the current challenges and limitations of this strategy. In general, this review offers an overview of the interaction between ferroptosis and cuproptosis in breast cancer, offering valuable perspectives for further research and clinical treatment.

Theoretical framework and emerging challenges of lipid metabolism in cancer

Elevated lipid metabolism is one of hallmarks of malignant tumors. Lipids not only serve as essential structural components of biological membranes but also provide energy and substrates for the proliferation of cancer cells and tumor growth. Cancer cells meet their lipid needs by coordinating the processes of lipid absorption, synthesis, transport, storage, and catabolism. As research in this area continues to deepen, numerous new discoveries have emerged, making it crucial for scientists to stay informed about the developments of cancer lipid metabolism. In this review, we first discuss relevant concepts and theories or assumptions that help us understand the lipid metabolism and -based cancer therapies. We then systematically summarize the latest advancements in lipid metabolism including new mechanisms, novel targets, and up-to-date pre-clinical and clinical investigations of anti-cancer treatment with lipid metabolism targeted drugs. Finally, we emphasize emerging research directions and therapeutic strategies, and discuss future prospective and emerging challenges. This review aims to provide the latest insights and guidance for research in the field of cancer lipid metabolism.

Crosstalk between lipid metabolism and EMT: emerging mechanisms and cancer therapy

Lipids are the key component of all membranes composed of a variety of molecules that transduce intracellular signaling and provide energy to the cells in the absence of nutrients. Alteration in lipid metabolism is a major factor for cancer heterogeneity and a newly identified cancer hallmark. Reprogramming of lipid metabolism affects the diverse cancer phenotypes, especially epithelial-mesenchymal transition (EMT). EMT activation is considered to be an essential step for tumor metastasis, which exhibits a crucial role in the biological processes including development, wound healing, and stem cell maintenance, and has been widely reported to contribute pathologically to cancer progression. Altered lipid metabolism triggers EMT and activates multiple EMT-associated oncogenic pathways. Although the role of lipid metabolism-induced EMT in tumorigenesis is an attractive field of research, there are still significant gaps in understanding the underlying mechanisms and the precise contributions of this interplay. Further study is needed to clarify the specific molecular mechanisms driving the crosstalk between lipid metabolism and EMT, as well as to determine the potential therapeutic implications. The increased dependency of tumor cells on lipid metabolism represents a novel therapeutic target, and targeting altered lipid metabolism holds promise as a strategy to suppress EMT and ultimately inhibit metastasis.

Serum metabolome profiling in patients with mild cognitive impairment reveals sex differences in lipid metabolism

Alzheimer's disease (AD) affects more women than men. Although women live longer than men, it is not longevity alone, but other factors, including metabolic changes, that contribute to the higher risk of AD in women. Metabolic pathways have been implicated in AD progression, but studies to date examined targeted pathways, leaving many metabolites unmeasured. Sex is often a neglected biological variable, and most metabolomic studies were not designed to investigate sex differences in metabolomic profiles. Here, we performed untargeted metabolomic profiling of sera from male and female patients with mild cognitive impairment (MCI), a common precursor to AD, and matched controls. We discovered significant metabolic changes in individuals with MCI, and found several pathways that were strongly associated with sex. Peptide energy metabolism demonstrated sexual dimorphism. Lipid pathways exhibited the strongest differences between female and male MCI patients, including specific phosphatidylcholine lipids, lysophospholipids, long-chain fatty acids, and monoacylglycerols. 1-palmitoleoyl glycerol and 1-arachidonoyl glycerol were higher in female MCI subjects than in male MCI subjects with no differences between control males and females. Conversely, specific dicarboxylic fatty acids were lower in female MCI subjects than male MCI subjects. In cultured astrocytes, 1-arachidonoyl glycerol promoted phosphorylation of the transcriptional regulator sphingosine kinase 2, which was inhibited by the transient receptor potential vanilloid 1 receptor antagonists, as well as chromatin remodelling. Overall, we identified novel sex-specific metabolites in MCI patients that could serve as biomarkers of MCI in both sexes, help further define AD etiology, and reveal new potential prevention strategies for AD.

Recent advances of lipid droplet-targeted AIE-active materials for imaging, diagnosis and therapy

Lipid droplets (LDs) are cellular organelles specialized in the storage and regulating the release of lipids critical for energy metabolism. As investigation on LDs deepens, the complex biological functions of LDs are revealed and their relationships with various diseases such as atherosclerosis, fatty liver, obesity, and cancer are uncovered. Fluorescence-based techniques with simple operations, visible results and high non-invasiveness are ideal tools for investigating LD-related biological processes and diseases. Materials with aggregation-induced emission (AIE) characteristics have emerged as promising candidates for investigating LDs due to their high signal-to-noise ratio (S/N), strong photostability, and large Stokes shift. This review discusses the principles and advantages of LD-targeting AIE probes for imaging LDs, diagnosis of LD-associated diseases including atherosclerotic plaques, liver diseases, acute kidney diseases and cancer, therapies with LD-targeting AIE-active photosensitizers and other relevant fields in the past five years. Through typical examples, we illustrate the status of investigating LD-related imaging, diagnosis of diseases and therapy with AIE materials. This review is expected to attract attentions from scientists with different research backgrounds and contribute to the further development of LD-targeting AIE materials.

Asiaticoside alleviated NAFLD by activating Nrf2 and inhibiting the NF-κB pathway

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a globally prevalent clinical problem of chronic liver disorder whose main pathogenic mechanisms are hepatic lipid accumulation, oxidative stress, and inflammatory reactions. Asiaticoside (Asi) is a compound derived from Centella asiatica, possesses antioxidant, antiphlogistic, antifibrotic, as well as wound healing properties.

PURPOSE

The aim of this study was to investigate the effects of Asi on NAFLD and its potential mechanisms.

STUDY DESIGN

Two versions of experimental models were constructed using free fatty acids (FFAs)-stimulated HepG2 cells along with high-fat diet (HFD)-incited NAFLD in mice.

METHODS

The pivotal action of Nrf2 was then explored using Ml-385 or Nrf2-/- mice.

RESULTS

The results indicated that Asi activated the Nrf2 to alleviate oxidative stress, inhibited the NF-κB to reduce the inflammatory response, and notably decreased lipid droplets and alleviated steatosis.

CONCLUSION

In conclusion, Asi demonstrates a potential to activate Nrf2 as well as inhibit the NF-κB pathway, there alleviate NAFLD.

The vitamin D receptor is essential for the replication of pseudorabies virus

The vitamin D receptor (VDR) is a nuclear steroid receptor that regulates the expression of genes across various biological functions. However, the role of VDR in pseudorabies virus (PRV) infection has not yet been explored. We discovered that VDR positively influenced PRV proliferation because knockdown of VDR impaired PRV proliferation, whereas its overexpression promoted it. Additionally, we observed that PRV infection upregulated VDR transcription alongside 1,25-dihydroxyvitamin D3 (VD3) synthesis, contingent on p53 activation. Furthermore, VDR knockdown hindered PRV-induced lipid synthesis, implicating VDR's involvement in this process. To decipher the mechanism behind VDR's stimulation of lipid synthesis during PRV infection, we conducted RNA sequencing (RNA-seq) and found significant enrichment of genes in the Ca2+ signaling pathway. Measurements of Ca2+ indicated that VDR facilitated Ca2+ absorption. Moreover, the PI3K/AKT/mTORC1 and AMPK/mTORC1 pathways were also enriched in our RNA-seq data. Interfering with VDR expression, or chelating Ca2+ using BAPTA-AM, markedly impacted the activation of PI3K/AKT/mTORC1 and AMPK/mTORC1 pathways, lipid synthesis, and PRV proliferation. In summary, our study demonstrates that PRV infection promotes VDR expression, thereby enhancing Ca2+ absorption and activating PI3K/AKT/mTORC1- and AMPK/mTORC1-mediated lipid synthesis. Our findings offer new insights into strategies for PRV prevention.IMPORTANCEVitamin D, beyond its well-known benefits for bone health and immune function, also plays a pivotal role in regulating gene expression through its receptor, the vitamin D receptor (VDR). Although VDR's influence spans multiple biological processes, its relationship with viral infections, particularly pseudorabies virus (PRV), remains underexplored. Our research illustrates a complex interplay where PRV infection boosts VDR expression, which in turn enhances Ca2+ absorption, leading to the activation of critical lipid synthesis pathways, PI3K/AKT/mTORC1 and AMPK/mTORC1. These findings not only deepen our understanding of the intricate dynamics between host molecular mechanisms and viral proliferation but also open avenues for exploring new strategies aimed at preventing PRV infection. By targeting components of the VDR-related signaling pathways, we can potentially develop novel therapeutic interventions against PRV and possibly other similar viral infections.

Ezetimibe Enhances Lipid Droplet and Mitochondria Contact Formation, Improving Fatty Acid Transfer and Reducing Lipotoxicity in Alport Syndrome Podocytes

Mitochondrial dysfunction is a critical factor in the pathogenesis of Alport syndrome (AS), contributing to podocyte injury and disease progression. Ezetimibe, a lipid-lowering drug, is known to inhibit cholesterol and fatty acid uptake and to reduce triglyceride content in the kidney cortex of mice with AS. However, its effects on lipid droplet (LD) utilization by mitochondria have not been explored. Transmission electron microscopy (TEM) and mitochondrial functional assays (ATP production, mitochondrial membrane potential, and citrate synthase activity) were used to investigate the impact of ezetimibe on LD-mitochondria contact formation and mitochondrial function in Col4a3KO (AS) and wildtype (WT) podocytes. TEM analysis revealed significant mitochondrial abnormalities in AS podocytes, including swollen mitochondria and reduced cristae density, while mitochondrial function assays showed decreased ATP production and lowered mitochondrial membrane potential. AS podocytes also demonstrated a higher content of LD but with reduced LD-mitochondria contact sites. Ezetimibe treatment significantly increased the number of LD-mitochondria contact sites, enhanced fatty acid transfer efficiency, and reduced intracellular lipid accumulation. These changes were associated with a marked reduction in the markers of lipotoxicity, such as apoptosis and oxidative stress. Mitochondrial function was significantly improved, evidenced by increased basal respiration, ATP production, maximal respiration capacity, and the restoration of mitochondrial membrane potential. Additionally, mitochondrial swelling was significantly reduced in ezetimibe-treated AS podocytes. Our findings reveal a novel role for ezetimibe in enhancing LD-mitochondria contact formation, leading to more efficient fatty acid transfer, reduced lipotoxicity, and improved mitochondrial function in AS podocytes. These results suggest that ezetimibe could be a promising therapeutic agent for treating mitochondrial dysfunction and lipid metabolism abnormalities in AS.

Metabolism: a potential regulator of neutrophil fate

Neutrophils are essential components of the innate immune system that defend against the invading pathogens, such as bacteria, viruses, and fungi, as well as having regulatory roles in various conditions, including tissue repair, cancer immunity, and inflammation modulation. The function of neutrophils is strongly related to their mode of cell death, as different types of cell death involve various cellular and molecular alterations. Apoptosis, a non-inflammatory and programmed type of cell death, is the most common in neutrophils, while other modes of cell death, including NETOsis, necrosis, necroptosis, autophagy, pyroptosis, and ferroptosis, have specific roles in neutrophil function regulation. Immunometabolism refers to energy and substance metabolism in immune cells, and profoundly influences immune cell fate and immune system function. Intercellular and intracellular signal transduction modulate neutrophil metabolism, which can, in turn, alter their activities by influencing various cell signaling pathways. In this review, we compile an extensive body of evidence demonstrating the role of neutrophil metabolism in their various forms of cell death. The review highlights the intricate metabolic characteristics of neutrophils and their interplay with various types of cell death.

Lipids and adipocytes involvement in tumor progression with a focus on obesity and diet

The adipose tissue is a complex organ that can play endocrine, metabolic, and immune regulatory roles in cancer. In particular, adipocytes provide metabolic substrates for cancer cell proliferation and produce signaling molecules that can stimulate cell adhesion, migration, invasion, angiogenesis, and inflammation. Cancer cells, in turn, can reprogram adipocytes towards a more inflammatory state, resulting in a vicious cycle that fuels tumor growth and evolution. These mechanisms are enhanced in obesity, which is associated with the risk of developing certain tumors. Diet, an exogenous source of lipids with pro- or anti-inflammatory functions, has also been connected to cancer risk. This review analyzes how adipocytes and lipids are involved in tumor development and progression, focusing on the relationship between obesity and cancer. In addition, we discuss how diets with varying lipid intakes can affect the disease outcomes. Finally, we introduce novel metabolism-targeted treatments and adipocyte-based therapies in oncology.

Serum metabolome profiling in patients with mild cognitive impairment reveals sex differences in lipid metabolism

Alzheimer's disease (AD) affects more women than men. Although women live longer than men, it is not longevity alone, but other factors, including metabolic changes, that contribute to the higher risk of AD in women. Metabolic pathways have been implicated in AD progression, but studies to date examined targeted pathways, leaving many metabolites unmeasured. Sex is often a neglected biological variable, and most metabolomic studies were not designed to investigate sex differences in metabolomic profiles. Here, we performed untargeted metabolomic profiling of sera from male and female patients with mild cognitive impairment (MCI), a common precursor to AD, and matched controls. We discovered significant metabolic changes in individuals with MCI, and found several pathways that were strongly associated with sex. Peptide energy metabolism demonstrated sexual dimorphism. Lipid pathways exhibited the strongest differences between female and male MCI patients, including specific phosphatidylcholine lipids, lysophospholipids, long-chain fatty acids, and monoacylglycerols. 1-palmitoleoyl glycerol and 1-arachidonoyl glycerol were higher in female MCI subjects than in male MCI subjects with no differences between control males and females. Conversely, specific dicarboxylic fatty acids were lower in female MCI subjects than male MCI subjects. In cultured astrocytes, 1-arachidonoyl glycerol promoted phosphorylation of the transcriptional regulator sphingosine kinase 2, which was inhibited by the transient receptor potential vanilloid 1 receptor antagonists, as well as chromatin remodelling. Overall, we identified novel sex-specific metabolites in MCI patients that could serve as biomarkers of MCI in both sexes, help further define AD etiology, and reveal new potential prevention strategies for AD.

Nanoparticles Fueled by Enzyme for the Treatment of Hyperlipidemic Acute Pancreatitis

Hyperlipidemic acute pancreatitis (HAP) is a serious inflammatory pancreatic disease commonly seen in patients with disorders of lipid metabolism. Decreasing blood triglyceride levels and proinflammatory factors can alleviate hyperlipidemic pancreatitis. The lipase that enhanced the Brownian motion of mesoporous silica in triglyceride solutions could accelerate decomposition of the lipid and improve the efficiency of absorption. In this study, we developed a mesoporous silica nanoparticle with dual modification of IL-6 aptamer and lipase for the treatment of HAP. The nanoparticle could increase the ability of particles to absorb inflammatory factor IL-6 and decompose triglycerides. For every 10 mg of the dual-modified nanoparticles, the efficiency of capturing IL-6 was approximately 9.67 pg/mL and of decomposing triglycerides was approximately 3.88 mg/mL in the plasma of HAP patients within 2 h. In summary, the mesoporous silica nanoparticle could absorb the IL-6 inflammatory factor through IL-6 aptamers and decompose triglycerides through lipase. Furthermore, based on clinically available plasma exchange technology, combined with our developed dual-modified nanoparticles, we designed an absorption device for the treatment of hyperlipidemic pancreatitis; it works to promote the treatment of hyperlipidemic pancreatitis.

Tandem Mass Spectrometry in Untargeted Lipidomics: A Case Study of Peripheral Blood Mononuclear Cells

Peripheral blood mononuclear cells (PBMCs), including lymphocytes, are important components of the human immune system. These cells contain a diverse array of lipids, primarily glycerophospholipids (GPs) and sphingolipids (SPs), which play essential roles in cellular structure, signaling, and programmed cell death. This study presents a detailed analysis of GP and SP profiles in human PBMC samples using tandem mass spectrometry (MS/MS). Hydrophilic interaction liquid chromatography (HILIC) and electrospray ionization (ESI) coupled with linear ion-trap MS/MS were employed to investigate the diagnostic fragmentation patterns that aided in determining regiochemistry in complex lipid extracts. Specifically, the study explored the fragmentation patterns of various lipid species, including phosphatidylcholines (PCs), phosphatidylethanolamines (PEs), their plasmalogen and lyso forms, phosphatidylserines (PSs), phosphatidylinositols (PIs), phosphatidylglycerols (PGs), sphingomyelins (SMs), and dihexosylceramides (Hex2Cer). Our comprehensive analysis led to the characterization of over 200 distinct lipid species, significantly expanding our understanding of PBMC lipidome complexity. A freely available spreadsheet tool for simulating MS/MS spectra of GPs is provided, enhancing the accessibility and reproducibility of this research. This study advances our knowledge of PBMC lipidomes and establishes a robust analytical framework for future investigations in lipidomics.

Actein ameliorates diet-induced obesity through the activation of AMPK-mediated white fat browning

BACKGROUND

Targeting white adipose tissue (WAT) browning to increase systemic energy expenditure is a promising therapeutic strategy to combat obesity. Actein from Actaea cimicifuga L. has recently been reported to ameliorate high fat-induced hepatic steatosis. However, the effect of actein on diet-induced obesity merits more and further investigation.

PURPOSE

We aimed to examine the anti-obesity potential of actein and unravel its actions on WAT browning.

METHODS

The effect of actein on diet-induced obesity was evaluated using a high-fat diet model in C57BL/6 mice. Systemic energy expenditure of mice was measured with a combined indirect calorimetry system. Quantitative real-time PCR analyses were performed to investigate the mRNA levels of genes involved in thermogenesis, browning, and lipolysis. The protein levels were assessed by Western blot. Moreover, WAT explants and a transwell co-culture system consisting of SVFs and adipocytes were constructed to study the mechanisms of actein on promoting WAT browning and lipolysis.

RESULTS

At a dosage of 5 mg/kg/d, actein not only protected mice against diet-induced obesity and insulin resistance, but also reversed pre-established obesity and glucose intolerance in mice. Meanwhile, actein facilitated systemic energy expenditure by activating WAT lipolysis and browning. Further, mechanistic studies revealed that actein indirectly induced epididymal adipocyte lipolysis and directly promoted a white-to-beige conversion of subcutaneous adipocytes by activating the AMPK signaling.

CONCLUSION

Actein ameliorated diet-induced obesity and was discovered as a natural lead compound directly targeting white-to-beige conversion of subcutaneous adipocytes, suggesting the potential of developing new therapies for obesity and associated metabolic disorders.

Diacylglycerol O-acyltransferase isoforms play a role in peridroplet mitochondrial fatty acid metabolism in bovine liver

Hepatocellular lipid accumulation characterizes fatty liver in dairy cows. Lipid droplets (LD), specialized organelles that store lipids and maintain cellular lipid homeostasis, are responsible for the ectopic storage of lipids associated with several metabolic disorders. In recent years, nonruminant studies have reported that LD-mitochondria interactions play an important role in lipid metabolism. Due to the role of diacylglycerol acyltransferase isoforms (DGAT1 and DGAT2) in LD synthesis, we explored mechanisms of mitochondrial fatty acid transport in ketotic cows using liver biopsies and isolated primary hepatocytes. Compared with healthy cows, cows with fatty liver had massive accumulation of LD and high protein expression of the triglyceride (TAG) synthesis-related enzymes DGAT1 and DGAT2, LD synthesis-related proteins perilipin 2 (PLIN2) and perilipin 5 (PLIN5), and the mitochondrial fragmentation-related proteins dynamin-related protein 1 (DRP1) and fission 1 (FIS1). In contrast, factors associated with fatty acid oxidation, mitochondrial fusion, and mitochondrial electron transport chain complex were lower compared with those in the healthy cows. In addition, transmission electron microscopy revealed significant contacts between LD-mitochondria in liver tissue from cows with fatty liver. Compared with isolated cytoplasmic mitochondria, expression of carnitine palmitoyl transferase 1A (CPT1A) and DRP1 was lower, but mitofusin 2 (MFN2) and mitochondrial electron transport chain complex was greater in isolated peridroplet mitochondria from hepatic tissue of cows with fatty liver. In vitro data indicated that exogenous free fatty acids (FFA) induced hepatocyte LD synthesis and mitochondrial dynamics consistent with in vivo results. Furthermore, DGAT2 inhibitor treatment attenuated the FFA-induced upregulation of PLIN2 and PLIN5 and rescued the impairment of mitochondrial dynamics. Inhibition of DGAT2 also restored mitochondrial membrane potential and reduced hepatocyte reactive oxygen species production. The present in vivo and in vitro results indicated functional differences are present among different types of mitochondria in the liver tissue of dairy cows with ketosis. Activity of DGAT2 may play a key role in maintaining liver mitochondrial function and lipid homeostasis in dairy cows during the transition period.

Going Rogue: Mechanisms, Regulation, and Roles of Mutationally Activated Gα in Human Cancer

G protein-coupled receptors (GPCRs) couple to heterotrimeric G proteins, comprised of α and βγ subunits, to convert extracellular signals into activation of intracellular signaling pathways. Canonically, GPCR-mediated activation results in the exchange of GDP for GTP on G protein α subunits (Gα) and the dissociation of Gα-GTP and G protein βγ subunits (Gβγ), both of which can regulate a variety of signaling pathways. Hydrolysis of bound GTP by Gα returns the protein to Gα-GDP and allows reassociation with Gβγ to reform the inactive heterotrimer. Naturally occurring mutations in Gα have been found at conserved glutamine and arginine amino acids that disrupt the canonical G protein cycle by inhibiting GTP hydrolysis, rendering these mutants constitutively active. Interestingly, these dysregulated Gα mutants are found in many different cancers due to their ability to sustain aberrant signaling without a need for activation by GPCRs. This review will highlight an increased recognition of the prevalence of such constitutively activating Gα mutations in cancers and the signaling pathways activated. In addition, we will discuss new knowledge regarding how these constitutively active Gα are regulated, how different mutations are biochemically distinct, and how mutationally activated Gα are unique compared with GPCR-activated Gα Lastly, we will discuss recent progress in developing inhibitors directly targeting constitutively active Gα mutants. SIGNIFICANCE STATEMENT: Constitutively activating mutations in G protein α subunits (Gα) widely occur in and contribute to the development of many human cancers. To develop ways to inhibit dysregulated, oncogenic signaling by these mutant Gα, it is crucial to better understand mechanisms that lead to constitutive Gα activation and unique mechanisms that regulate mutationally activated Gα in cells. The prevalence of activating mutations in Gα in various cancers makes Gα proteins compelling targets for the development of therapeutics.

TREM2 aggravates sepsis by inhibiting fatty acid oxidation via the SHP1/BTK axis

Impaired fatty acid oxidation (FAO) and the therapeutic benefits of FAO restoration have been revealed in sepsis. However, the regulatory factors contributing to FAO dysfunction during sepsis remain inadequately clarified. In this study, we identified a subset of lipid-associated macrophages characterized by high expression of trigger receptor expressed on myeloid cells 2 (TREM2) and demonstrated that TREM2 acted as a suppressor of FAO to increase the susceptibility to sepsis. TREM2 expression was markedly upregulated in sepsis patients and correlated with the severity of sepsis. Knockout of TREM2 in macrophages improved the survival rate and reduced inflammation and organ injuries of sepsis mice. Notably, TREM2-deficient mice exhibited decreased triglyceride accumulation and an enhanced FAO rate. Further observations showed that the blockade of FAO substantially abolished the alleviated symptoms observed in TREM2-knockout mice. Mechanically, we demonstrated that TREM2 interacted with the phosphatase SHP1 to inhibit bruton tyrosine kinase-mediated (BTK-mediated) FAO in sepsis. Our findings expand the understanding of FAO dysfunction in sepsis and reveal TREM2 as a critical regulator of FAO that may provide a promising target for the clinical treatment of sepsis.

Preparation of highly stable immobilized Candida antarctica lipase B (CALB) through adjusting the surface properties of carrier: Preparation, characterization and performance evaluation

The stability of the immobilized lipase is the key factor that determines the economy and feasibility of its industrial application. Here, two robust immobilized Candida antarctica lipase B (CALB) were prepared through adjusting the surface properties of ECR1030 resin. Silane coupling agent (SCA) and dialdehyde cellulose (DAC) were employed to modify the carrier surface. Contact angle measurement showed that the hydrophobicity of the modified carrier increased first, and then decreased with the increase of the chain length of SCA. FTIR results showed that Si-O-Si bond and aldehyde group were attached to ECR1030, respectively, indicating that the ECR1030 resin was successfully modified. Meanwhile, the NH and CN bond were observed in the corresponding immobilized CALB, suggesting CALB was immobilized onto the modified carriers. The effects of immobilization conditions on CALB immobilization was further investigated, and the C8-ECR1030-CALB and DAC-ECR1030-CALB with the activity of 12,736 U/g and 11,962 U/g were obtained. Moreover, the stability of the immobilized lipases was evaluated and compared with the commercial Novozym 435. The C8-ECR1030-CALB and DAC-ECR1030-CALB exhibited comparable or superior stability to Novozym 435 and showed better deacidification effect than Novozym 435. This study paves road for further study involving preparation of highly stable immobilized lipase.

Blocking ACSL6 Compromises Autophagy via FLI1-Mediated Downregulation of COLs to Radiosensitize Lung Cancer

Lung cancer (LC) is the leading cause of cancer-related mortality worldwide. Radiotherapy is the main component of LC treatment; however, its efficacy is often limited by radioresistance development, resulting in unsatisfactory clinical outcomes. Here, we found that LC radiosensitivity is up-regulated by decreased expression of long-chain acyl-CoA synthase 6 (ACSL6) after irradiation. Deletion of ACSL6 results in significant elevation of Friend leukemia integration 1 transcription factor (FLI1) and a marked decline of collagens (COLs). Blocking of ACSL6 impairs the tumor growth and upregulates FLI1, which reduces the levels of COLs and compromises irradiation-induced autophagy, leading to considerable therapeutic benefits during radiotherapy. Moreover, the direct interaction between ACSL6 and FLI1 and engagement between FLI1 and COLs indicates the involvement of the ACSL6-FLI1-COL axis. Finally, the potently adjusted autophagy flux reduces its otherwise contributive capability in surviving irradiation stress and leads to satisfactory radiosensitization for LC radiotherapy. These results demonstrate that enhanced ACSL6 expression promotes the aggressive performance of irradiated LC through increased FLI1-COL-mediated autophagy flux. Thus, the ACSL6-FLI1-Col-autophagy axis may be targeted to enhance the radiosensitivity of LC and improve the management of LC in radiotherapy.

Caffeic acid: A game changer in pine wood nematode overwintering survival

Following the invasion by the pine wood nematode (PWN) into north-east China, a notable disparity in susceptibility was observed among Pinaceae species. Larix olgensis exhibited marked resilience and suffered minimal fatalities, while Pinus koraiensis experienced significant mortality due to PWN infection. Our research demonstrated that the PWNs in L. olgensis showed a 13.43% reduction in lipid content compared to P. koraiensis (p < 0.05), which was attributable to the accumulation of caffeic acid in L. olgensis. This reduction in lipid content was correlated with a decreased overwintering survival of PWNs. The diminished lipid reserves were associated with substantial stunting in PWNs, including reduced body length and maximum body width. The result suggests that lower lipid content is a major factor contributing to the lower overwintering survival rate of PWNs in L. olgensis induced by caffeic acid. Through verification tests, we concluded that the minimal fatalities observed in L. olgensis could be attributed to the reduced overwintering survival of PWNs, a consequence of caffeic acid-induced stunting. This study provides valuable insights into PWN-host interactions and suggests that targeting caffeic acid biosynthesis pathways could be a potential strategy for managing PWN in forest ecosystems.

Copper and liver fibrosis in MASLD: the two-edged sword of copper deficiency and toxicity

Copper is a trace metal whose absence or deficiency can cause structural and functional alterations that can be corrected by copper administration. Copper excess is associated with significant liver toxicity, such as that seen in Wilson’s disease, which often exhibits liver steatosis and can be managed by copper sequestrants. Copper, due to its ability to either accept or donate electrons, is a cofactor in many physiological redox reactions, playing an essential role in cell energy homeostasis, detoxification of reactive oxygen species, and hepatic immunometabolism. Given these facts, it is reasonable to speculate that copper might be involved in the pathogenesis of liver fibrosis in the setting of metabolic dysfunction-associated fatty liver disease (MASLD). To address this research question, a narrative review of published studies was conducted, spanning from the needs, sources, and toxicity of copper to Menkes and Wilson’s disease. Most epidemiological studies have demonstrated that MASLD is associated with copper deficiency. However, several studies show that MASLD is associated with copper excess and very few conclude that copper is not associated with MASLD. Therefore, the putative pathomechanisms associating both copper excess and deficiency with MASLD development and progression are reviewed. In conclusion, epidemiological and pathogenic data support the notion that well-balanced copper homeostasis is a prerequisite for liver health. Accordingly, both copper excess and deficiency may potentially predispose to liver fibrosis via the development of MASLD. Therefore, studies aimed at restoring normal bodily stores of copper should be tailored according to precision medicine approaches based on the specific features of copper metabolism in individual MASLD patients.

Salusin‑α alleviates lipid metabolism disorders via regulation of the downstream lipogenesis genes through the LKB1/AMPK pathway

Lipid metabolism disorders are a major cause of several chronic metabolic diseases which seriously affect public health. Salusin‑α, a vasoactive peptide, has been shown to attenuate lipid metabolism disorders, although its mechanism of action has not been reported. To investigate the effects and potential mechanisms of Salusin‑α on lipid metabolism, Salusin‑α was overexpressed or knocked down using lentiviral vectors. Hepatocyte steatosis was induced by free fatty acid (FFA) after lentiviral transfection into HepG2 cells. The degree of lipid accumulation was assessed using Oil Red O staining and by measuring several biochemical indices. Subsequently, bioinformatics was used to analyze the signaling pathways that may have been involved in lipid metabolism disorders. Finally, semi‑quantitative PCR and western blotting were used to verify the involvement of the liver kinase B1 (LKB1)/AMPK pathway. Compound C, an inhibitor of AMPK, was used to confirm this mechanism's involvement further. The results showed that Salusin‑α significantly attenuated lipid accumulation, inflammation and oxidative stress. In addition, Salusin‑α increased the levels of LKB1 and AMPK, which inhibited the expression of sterol regulatory element binding protein‑1c, fatty acid synthase and acetyl‑CoA carboxylase. The addition of Compound C abrogated the Salusin‑α‑mediated regulation of AMPK on downstream signaling molecules. In summary, overexpression of Salusin‑α activated the LKB1/AMPK pathway, which in turn inhibited lipid accumulation in HepG2 cells. This provides insights into the potential mechanism underlying the mechanism by which Salusin‑α ameliorates lipid metabolism disorders while identifying a potential therapeutic target.

MiR-196a Promotes Lipid Deposition in Goat Intramuscular Preadipocytes by Targeting MAP3K1 and Activating PI3K-Akt Pathway

Meat quality in goats is partly determined by the intramuscular fat (IMF) content, which is associated with the proliferation and differentiation of intramuscular preadipocytes. Emerging studies have suggested that miRNA plays a crucial role in adipocyte proliferation and differentiation. In our recent study, we observed the expression variations in miR-196a in the longissimus dorsi muscle of Jianzhou goats at different ages. However, the specific function and underlying mechanism of miR-196a in IMF deposition are still unclear. This study demonstrated that miR-196a significantly enhanced adipogenesis and apoptosis and reduced the proliferation of preadipocytes. Subsequently, RNA-seq was employed to determine genes regulated by miR-196a, and 677 differentially expressed genes were detected after miR-196a overexpression. The PI3K-Akt pathway was identified as activated in miR-196a regulating intramuscular adipogenesis via Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and further verified via Western blot and rescue assays. Lastly, using RT-qPCR, Western blot, dual-luciferase, and rescue assays, we found that miR-196a promoted adipogenesis and suppressed the proliferation of intramuscular preadipocytes by the downregulation of MAP3K1. In summary, these results suggest that miR-196a regulates IMF deposition by targeting MAP3K1 and activating the PI3K-Akt pathway and provide a theoretical foundation for improving goat meat quality through molecular breeding.

Metabolic alterations in vitamin D deficient systemic lupus erythematosus patients

Vitamin D deficiency is increasingly common in systemic lupus erythematosus (SLE) patients and is associated with the disease activity and proteinuria. Recently, alterations in metabolism have been recognized as key regulators of SLE pathogenesis. Our objective was to identify differential metabolites in the serum metabolome of SLE with vitamin D deficiency. In this study, serum samples from 31 SLE patients were collected. Levels of 25(OH)D3 were assayed by ELISA. Patients were divided into two groups according to their vitamin D level (20 ng/ml). Untargeted metabolomics were used to study the metabolite profiles in serum by high-performance liquid chromatography-tandem mass spectrometry. Subsequently, we performed metabolomics profiling analysis to identify 52 significantly altered metabolites in vitamin D deficient SLE patients. The area under the curve (AUC) from ROC analyses was calculated to assess the diagnostic potential of each candidate metabolite biomarker. Lipids accounted for 66.67% of the differential metabolites in the serum, highlighted the disruption of lipid metabolism. The 52 differential metabolites were mapped to 27 metabolic pathways, with fat digestion and absorption, as well as lipid metabolism, emerging as the most significant pathways. The AUC of (S)-Oleuropeic acid and 2-Hydroxylinolenic acid during ROC analysis were 0.867 and 0.833, respectively, indicating their promising diagnostic potential. In conclusion, our results revealed vitamin D deficiency alters SLE metabolome, impacting lipid metabolism, and thrown insights into the pathogenesis and diagnosis of SLE.

Lipases are differentially regulated by hormones to maintain free fatty acid homeostasis for insect brain development

BACKGROUND

Free fatty acids (FFAs) play vital roles as energy sources and substrates in organisms; however, the molecular mechanism regulating the homeostasis of FFA levels in various circumstances, such as feeding and nonfeeding stages, is not fully clarified. Holometabolous insects digest dietary triglycerides (TAGs) during larval feeding stages and degrade stored TAGs in the fat body during metamorphosis after feeding cessation, which presents a suitable model for this study.

RESULTS

This study reported that two lipases are differentially regulated by hormones to maintain the homeostasis of FFA levels during the feeding and nonfeeding stages using the lepidopteran insect cotton bollworm Helicoverpa armigera as a model. Lipase member H-A-like (Lha-like), related to human pancreatic lipase (PTL), was abundantly expressed in the midgut during the feeding stage, while the monoacylglycerol lipase ABHD12-like (Abhd12-like), related to human monoacylglycerol lipase (MGL), was abundantly expressed in the fat body during the nonfeeding stage. Lha-like was upregulated by juvenile hormone (JH) via the JH intracellular receptor methoprene-tolerant 1 (MET1), and Abhd12-like was upregulated by 20-hydroxyecdysone (20E) via forkhead box O (FOXO) transcription factor. Knockdown of Lha-like decreased FFA levels in the hemolymph and reduced TAG levels in the fat body. Moreover, lipid droplets (LDs) were small, the brain morphology was abnormal, the size of the brain was small, and the larvae showed the phenotype of delayed pupation, small pupae, and delayed tissue remodeling. Knockdown of Abhd12-like decreased FFA levels in the hemolymph; however, TAG levels increased in the fat body, and LDs remained large. The development of the brain was arrested at the larval stage, and the larvae showed a delayed pupation phenotype and delayed tissue remodeling.

CONCLUSIONS

The differential regulation of lipases expression by different hormones determines FFAs homeostasis and different TAG levels in the fat body during the feeding larval growth and nonfeeding stages of metamorphosis in the insect. The homeostasis of FFAs supports insect growth, brain development, and metamorphosis.