Lipid Droplet Formation Research Articles

Inhibiting lipid droplet biogenesis enhances host protection against hypervirulent Klebsiella pneumoniae infections.

Hypervirulent Klebsiella pneumoniae (hvKp), an emerging Kp subtype, has become a serious global pathogen. However, the information regarding host interactions and innate immune responses during hvKp infection is limited. Here, we found that hvKp clinical strains increased triacylglycerol synthesis, resulting in lipid droplets (LDs) formation via the mammalian target of rapamycin signaling pathway in RAW264.7 cells. Treatment with rapamycin, an inhibitor of this pathway, affected LDs formation and antimicrobial responses against clinical hvKp infections. In accordance with the role of LDs in modulating inflammation, the pharmacological inhibition of lipogenesis reduced proinflammatory cytokine expression during hvKp infections. In addition, inhibition of LDs formation using pharmacological inhibitors and knockdown of lipogenesis regulators decreased the intracellular survival of hvKp in macrophages. Moreover, inhibiting LDs biogenesis reduced mortality, weight loss, and bacterial loads in hvKp-infected mice. Collectively, these data suggest that LDs biogenesis is crucial in linking host immune responses to clinical hvKp infections.

TMET-07. RADIORESISTANT GLIOBLASTOMA EVADES MITOCHONDRIAL LIPOTOXICITY THROUGH ALTERED DGKB AND DGAT1

Abstract Glioblastoma (GBM) is the most common and aggressive primary brain tumor, with a median survival of only 15 months despite multimodal therapy. Radiotherapy is a conventional therapy of GBM treatment, but the development of radioresistance often leads to tumor recurrence and treatment failure. To elucidate the molecular mechanisms underlying radioresistance in GBM, we established radioresistant GBM cell lines through repeated exposure to ionizing radiation. Transcriptomic analysis revealed that diacylglycerol kinase beta (DGKB), an enzyme that converts diacylglycerol (DAG) to phosphatidic acid, was significantly downregulated in radioresistant GBM cells. Functional studies demonstrated that knockdown of DGKB or expression of a kinase-dead DGKB mutant resulted in DAG accumulation and reduced fatty acid oxidation. Conversely, overexpression of DGKB activated fatty acid oxidation, increased reactive oxygen species (ROS) production, and sensitized GBM cells to radiation. Interestingly, we found that radiation upregulated the expression of diacylglycerol acyltransferase 1 (DGAT1), which catalyzes the conversion of DAG to triglycerides. Knockdown of DGAT1 using shRNA or miR-3918 mimic reduced lipid droplet formation and enhanced radiosensitivity both in vitro and in vivo. Furthermore, using Connectivity Map, we identified cladribine as a potential radiosensitizing agent that increases DGKB and decreases DGAT1. Cladribine effectively sensitized GBM cells to radiation and significantly prolonged the survival of mice bearing GBM xenografts. In conclusion, our study reveals a novel mechanism by which radioresistant GBM cells maintain lipid homeostasis through downregulation of DGKB and upregulation of DGAT1 to evade lethal mitochondrial lipotoxicity. Targeting the DGKB-DGAT1 axis represents a promising therapeutic strategy to overcome radioresistance and improve the outcomes of GBM patients.

Lipid Droplet Biology in Obesity: Mechanisms of Lipid Storage and Mobilization in Metabolic Disease

Lipid droplets (LDs) are dynamic organelles that play a central role in lipid storage and mobilization, particularly in the context of metabolic diseases like obesity. Obesity is characterized by excessive accumulation of triglycerides within adipocytes, leading to metabolic dysregulation and associated comorbidities such as insulin resistance, type 2 diabetes, and cardiovascular disease. This review explores the biology of lipid droplets in the setting of obesity, focusing on the mechanisms of lipid storage and mobilization. We discuss the key regulatory proteins involved in LD formation and degradation, including perilipins, adipose triglyceride lipase (ATGL), and hormone-sensitive lipase (HSL). Additionally, the roles of lipophagy, autophagy, and lipolysis in lipid mobilization are explored. We also highlight how dysregulation of lipid droplet biology contributes to obesity-related metabolic disorders, with emphasis on the impact of lipid droplet dysfunction on cellular signaling, lipid metabolism, and inflammation. Finally, we discuss the potential of targeting LDs as a therapeutic strategy for treating obesity and its metabolic complications. Keywords: Lipid droplets, Obesity, Lipid storage, Lipid mobilization, Metabolic disease, Lipolysis, Lipophagy, Triglycerides

FABP4-mediated lipid accumulation and lipolysis in tumor-associated macrophages promote breast cancer metastasis.

A high density of tumor-associated macrophages (TAMs) is associated with poorer prognosis and survival in breast cancer patients. Recent studies have shown that lipid accumulation in TAMs can promote tumor growth and metastasis in various models. However, the specific molecular mechanisms that drive lipid accumulation and tumor progression in TAMs remain largely unknown. Herein, we demonstrated that unsaturated fatty acids (FAs), unlike saturated ones, are more likely to form lipid droplets in murine macrophages. Specifically, unsaturated FAs, including linoleic acids (LA), activate the FABP4/CEBPα pathway, leading to triglyceride synthesis and lipid droplet formation. Furthermore, FABP4 enhances lipolysis and FA utilization by breast cancer cell lines, which promotes cancer cell migration in vitro and metastasis in vivo. Notably, a deficiency of FABP4 in murine macrophages significantly reduces LA-induced lipid metabolism. Therefore, our findings suggest FABP4 as a crucial lipid messenger that facilitates unsaturated FA-mediated lipid accumulation and lipolysis in TAMs, thus contributing to the metastasis of breast cancer.

FABP4-mediated lipid accumulation and lipolysis in tumor-associated macrophages promote breast cancer metastasis

A high density of tumor-associated macrophages (TAMs) is associated with poorer prognosis and survival in breast cancer patients. Recent studies have shown that lipid accumulation in TAMs can promote tumor growth and metastasis in various models. However, the specific molecular mechanisms that drive lipid accumulation and tumor progression in TAMs remain largely unknown. Herein, we demonstrated that unsaturated fatty acids (FAs), unlike saturated ones, are more likely to form lipid droplets in murine macrophages. Specifically, unsaturated FAs, including linoleic acids (LA), activate the FABP4/CEBPα pathway, leading to triglyceride synthesis and lipid droplet formation. Furthermore, FABP4 enhances lipolysis and FA utilization by breast cancer cell lines, which promotes cancer cell migration in vitro and metastasis in vivo. Notably, a deficiency of FABP4 in murine macrophages significantly reduces LA-induced lipid metabolism. Therefore, our findings suggest FABP4 as a crucial lipid messenger that facilitates unsaturated FA-mediated lipid accumulation and lipolysis in TAMs, thus contributing to the metastasis of breast cancer.

The α/β hydrolase domain-containing protein 1 (ABHD1) acts as a lysolipid lipase and is involved in lipid droplet formation

Abstract Lipid droplets (LDs) are the major sites of lipid and energy homeostasis. However, few LD biogenesis proteins have been identified. Using model microalga Chlamydomonas, we show that ABHD1, an α/β-hydrolase domain-containing protein, is localized to the LD surface and stimulates LD formation through two actions: one enzymatic and one structural. The knockout mutants contained similar amounts of triacylglycerols (TAG) but their LDs showed a higher content of lyso-derivatives of betaine lipid diacylglyceryl-N,N,N-trimethylhomoserine (DGTS). Over-expression of ABHD1 increased LD abundance and boosted TAG content. Purified recombinant ABHD1 hydrolyzed lyso-DGTS, producing a free fatty acid and a glyceryltrimethylhomoserine. In vitro droplet-embedded vesicles showed ABHD1 promoted LD emergence. Taken together, these results identify ABHD1 as a new player in LD formation by its lipase activity on lyso-DGTS and by its distinct biophysical property. This study further suggests that lipases targeted to LDs and able to act on their polar lipid coat may be interesting tools to promote LD assembly in eukaryotic cells.

Docosahexaenoic acid alleviated liver lipid deposition and health damage induced by cholesterol accumulation in hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂)

Cholesterol accumulation can be a critical pathological marker and, while, the cholesterol-lowering potential of docosahexaenoic acid (DHA) has been documented extensively in mammals, its effects in fish are unclear. The present study investigated the adverse effects of cholesterol accumulation on liver health, and evaluated DHA as a potential cholesterol-lowering agent to mitigate liver damage induced by high cholesterol (HC) intake in hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂). Grouper were fed either a control diet or an HC (1.6 %) diet supplemented with varying levels of DHA (0, 0.5, 1, 2 %) for eight weeks. The HC diet significantly increased condition factor (CF), mesenteric fat index (MFI), and lipid, cholesterol and triglyceride accumulation in liver. Supplementing the HC diet with 0.5 % DHA significantly reduced CF, MFI and liver lipid contents. Moreover, HC intake increased aspartate transaminase (AST) and alanine transaminase (ALT) activities in serum, and malondialdehyde (MDA) content and the expression of gene related to inflammatory responses and apoptosis in liver. In addition, HC intake significantly reduced mitochondrial biogenesis and total antioxidant capacity in liver. However, supplementing the HC diet with 0.5 % DHA significantly decreased liver cholesterol accumulation by inhibiting cholesterol synthesis and promoting cholesterol efflux, and significantly reduced liver triglyceride content by inhibiting the expression of genes associated with lipogenesis and lipid droplet formation. Furthermore, supplementation of the HC diet with 0.5 % DHA significantly reduced the activities of ALT and AST in serum, and MDA content and the expression of genes associated with inflammation, apoptosis and antioxidation in liver, and enhanced liver mitochondrial biogenesis. Overall, the results indicated that DHA supplementation mitigated liver cholesterol accumulation by inhibiting cholesterol synthesis and promoting cholesterol efflux, and enhanced mitochondrial function, boosted antioxidant capacity, and reduced inflammation in liver of grouper fed the HC diet, ultimately alleviating liver damage caused by cholesterol accumulation. The present study elucidated the detrimental effects of cholesterol accumulation on liver health in aquatic animals and proposed DHA as a potential intervention for mitigating health issues associated with cholesterol overload.

Therapeutic role of physalin A in the pathogenesis of Graves’ orbitopathy

Background Graves’ orbitopathy (GO) is an autoimmune condition that causes serious ocular symptoms; its treatment strategies are limited. Physalin A is a phytosterol that has shown various therapeutic properties, including anti-inflammatory and anti-fibrotic effects. In this study, we investigated whether physalin A could inhibit inflammation, fibrosis, hyaluronan (hyaluronic acid) production, and adipogenesis, which are crucial to the pathogenesis of GO. Methods Orbital tissue explants were obtained from patients with GO during orbital decompression surgery and healthy controls. Orbital fibroblasts (OFs) were isolated and treated with different concentrations of physalin A. Using western blot and ELISA analyses, we determined the effects of physalin A on OFs. Results Physalin A treatment suppressed the production of interleukin (IL)-1β-induced prostaglandin E2 (PGE2) and pro-inflammatory molecules, including cyclooxygenase (COX)-2, IL-6, IL-8, and intercellular adhesion molecule (ICAM)-1. We discovered that physalin A attenuated hyaluronan production induced by IL-1β or insulin-like growth factor (IGF)-1. Moreover, physalin A reduced lipid droplet formation and production of peroxisome proliferator activator (PPAR) γ, CCAAT-enhancer-binding protein (C/EBP) α, C/EBP β, sterol regulatory element binding protein (SREBP)-1, leptin, and adiponectin proteins. Physalin A suppressed the phosphorylation of extracellular signal-related kinase (ERK), nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB), and suppressor of mothers against decapentaplegic (SMAD) 2 signaling protein. Conclusions Our study suggests that the major mechanisms by which physalin A suppresses GO include reducing inflammation, fibrosis, hyaluronan production, and adipogenesis in OFs. The findings of this study provide evidence of the therapeutic effect of physalin A in GO.

Metabolic Checkpoints in Rheumatoid Arthritis

BackgroundRheumatoid Arthritis is a systemic autoimmune disease affecting 0.5-1% of the population. Despite a growing therapeutic armamentarium, RA remains incurable, and many patients suffer significant morbidity over time. The strongest genetic risk derives from HLA class II polymorphisms, implicating T cells as pathogenic drivers. Innate immune cells, e.g. monocytes and macrophages (Mⱷ) contribute to chronic tissue inflammation through an array of pro-inflammatory functions but also present antigen to autoreactive T cells. Differentiation, survival, and effector functions of both T cells and Mⱷ are ultimately controlled by their bioenergetic and biosynthetic programs, identifying cellular metabolism as a critical disease mechanism in RA. ObjectivesSummarize current knowledge about metabolic conditions in the RA joint and disease-relevant metabolic circuits shaping the effector repertoire of RA T cells and Mⱷ. ResultsThe rheumatoid joint is a glucose deplete tissue environment, selecting for invading immune cells that can survive on non-glucose fuel sources. Inflamed synovium instead offers the amino acid glutamine and RA CD4+ T cells and RA Mⱷ rely on glutamine and glutamate to support their pathogenic functions. The metabolic hallmark of RA T cells is their low mitochondrial performance, resulting in low ATP production, low generation of reactive oxygen species (ROS) and low availability of tricarboxylic acid (TCA) cycle intermediates, all shifting RA T cells towards autoreactivity. The underlying defect stems from insufficient repair of mitochondrial DNA (mtDNA). Functional consequences include reversal of the TCA cycle, accumulation of citrate and lack of malate production. Excessive citrate promotes cytoskeletal hyperacetylation, creating hypermigratory and tissue-invasive T cells. Surplus acetyl-CoA supports lipid droplet formation and lipotoxicity. Lack of malate production disrupts the malate-aspartate shuttle, restricts recovery of cytosolic NAD and drives the endoplasmic reticulum (ER) into expansion. The bioenergetically stressed ER accumulates TNF mRNA and turns RA T cells into TNF superproducers. ATP low production renders RA T cells susceptible to cell death, depositing highly inflammatory mtDNA in the tissue. Mitochondrial deficiency leads to a slowdown in glycolysis and pyruvate processing, such that RA CD4+ T cells shunt glucose towards the pentose phosphate pathway to support nucleotide synthesis and clonal proliferation. Metabolically deprived CD4+ T cells partner with Mⱷ that have highly functional mitochondria. A hallmark of RA Mⱷ is the high expression of the DNA binding protein RFX5, which co-ordinates adaptations to metabolic needs with function. RFX5 upregulates HLA-DR expression and induces the glutaminolytic enzyme glutamate dehydrogenase 1 (GLUD1), providing bioenergetic resources for antigen presentation and survival in the tissue. In essence, RA CD4+ T cells and Mⱷ function in a metabolically challenging environment and rewire their cellular metabolism to survive. Metabolic adaptations promote immunostimulation and tissue inflammation, triggering and sustaining rheumatoid synovitis.

The Lipid Droplet Protein DHRS3 Is a Regulator of Melanoma Cell State.

Lipid droplets are fat storage organelles composed of a protein envelope and lipid-rich core. Regulation of this protein envelope underlies differential lipid droplet formation and function. In melanoma, lipid droplet formation has been linked to tumor progression and metastasis, but it is unknown whether lipid droplet proteins play a role. To address this, we performed proteomic analysis of the lipid droplet envelope in melanoma. We found that lipid droplet proteins were differentially enriched in distinct melanoma states; from melanocytic to undifferentiated. DHRS3, which converts all-trans-retinal to all-trans-retinol, is upregulated in the MITFLO/undifferentiated/neural crest-like melanoma cell state and reduced in the MITFHI/melanocytic state. Increased DHRS3 expression is sufficient to drive MITFHI/melanocytic cells to a more undifferentiated/invasive state. These changes are due to retinoic acid-mediated regulation of melanocytic genes. Our data demonstrate that melanoma cell state can be regulated by expression of lipid droplet proteins which affect downstream retinoid signaling.

Protumoral lipid droplet-loaded macrophages are enriched in human glioblastoma and can be therapeutically targeted.

Glioblastoma presents a formidable clinical challenge because of its complex microenvironment. Here, we characterized tumor-associated foam cells (TAFs), a type of lipid droplet-loaded macrophage, in human glioblastoma. Through extensive analyses of patient tumors, together with in vitro and in vivo investigations, we found that TAFs exhibit distinct protumorigenic characteristics related to hypoxia, mesenchymal transition, angiogenesis, and impaired phagocytosis, and their presence correlates with worse outcomes for patients with glioma. We further demonstrated that TAF formation is facilitated by lipid scavenging from extracellular vesicles released by glioblastoma cells. We found that targeting key enzymes involved in lipid droplet formation, such as diacylglycerol O-acyltransferase or long-chain acyl-CoA synthetase, effectively disrupted TAF functionality. Together, these data highlight TAFs as a prominent immune cell population in glioblastoma and provide insights into their contribution to the tumor microenvironment. Disrupting lipid droplet formation to target TAFs may represent an avenue for future therapeutic development for glioblastoma.

Targeted modulation of pennycress lipid droplet proteins impacts droplet morphology and seed oil content.

Lipid droplets (LDs) are unusual organelles that have a phospholipid monolayer surface and a hydrophobic matrix. In oilseeds, this matrix is nearly always composed of triacylglycerols (TGs) for efficient storage of carbon and energy. Various proteins play a role in their assembly, stability and turnover, and even though the major structural oleosin proteins in seed LDs have been known for decades, the factors influencing LD formation and dynamics are still being uncovered mostly in the "model oilseed" Arabidopsis. Here we identified several key LD biogenesis proteins in the seeds of pennycress, a potential biofuel crop, that were correlated previously with seed oil content and characterized here for their participation in LD formation in transient expression assays and stable transgenics. One pennycress protein, the lipid droplet associated protein-interacting protein (LDIP), was able to functionally complement the Arabidopsis ldip mutant, emphasizing the close conservation of lipid storage among these two Brassicas. Moreover, loss-of-function ldip mutants in pennycress exhibited increased seed oil content without compromising plant growth, raising the possibility that LDIP or other LD biogenesis factors may be suitable targets for improving yields in oilseed crops more broadly.

Loss of CLN3 in microglia leads to impaired lipid metabolism and myelin turnover

Loss-of-function mutations in CLN3 cause juvenile Batten disease, featuring neurodegeneration and early-stage neuroinflammation. How loss of CLN3 function leads to early neuroinflammation is not yet understood. Here, we have comprehensively studied microglia from Cln3∆ex7/8 mice, a genetically accurate disease model. Loss of CLN3 function in microglia leads to lysosomal storage material accumulation and abnormal morphology of subcellular organelles. Moreover, pathological proteomic signatures are indicative of defects in lysosomal function and abnormal lipid metabolism. Consistent with these findings, CLN3-deficient microglia are unable to efficiently turnover myelin and metabolize the associated lipids, showing defects in lipid droplet formation and cholesterol accumulation. Accordingly, we also observe impaired myelin integrity in aged Cln3∆ex7/8 mouse brain. Autophagy inducers and cholesterol-lowering drugs correct the observed microglial phenotypes. Taken together, these data implicate a cell-autonomous defect in CLN3-deficient microglia that impacts their ability to support neuronal cell health, suggesting microglial targeted therapies should be considered for CLN3 disease.

Unveiling Novel Mechanism of CIDEB in Fatty Acid Synthesis Through ChIP-Seq and Functional Analysis in Dairy Goat

Goat milk is abundant in nutrients, particularly in milk fats, which confer health benefits to humans. Exploring the regulatory mechanism of fatty acid synthesis is highly important to understand milk composition manipulation. In this study, we used chromatin immunoprecipitation sequencing (ChIP-seq) on goat mammary glands at different lactation stages which revealed a novel lactation regulatory factor: cell death-inducing DFFA-like effector B (CIDEB). RT-qPCR results revealed that CIDEB was significantly upregulated during lactation in dairy goats. CIDEB overexpression significantly increased the expression levels of genes involved in fatty acid synthesis (ACACA, SCD1, p < 0.05; ELOVL6, p < 0.01), lipid droplet formation (XDH, p < 0.05), and triacylglycerol (TAG) synthesis (DGAT1, p < 0.05; GPAM, p < 0.01) in goat mammary epithelial cells (GMECs). The contents of lipid droplets, TAG, and cholesterol were increased (p < 0.05) in CIDEB-overexpressing GMECs, and knockdown of CIDEB led to the opposite results. In addition, CIDEB knockdown significantly decreased the proportion of C16:0 and total C18:2. Luciferase reporter assays indicated that X-box binding protein 1 (XBP1) promoted CIDEB transcription via XBP1 binding sites located in the CIDEB promoter. Furthermore, CIDEB knockdown attenuated the stimulatory effect of XBP1 on lipid droplet accumulation. Collectively, these findings elucidate the critical regulatory roles of CIDEB in milk fat synthesis, thus providing new insights into improving the quality of goat milk.

Mitochondria-giant lipid droplet proximity and autophagy suppression in nitrogen-depleted oleaginous yeast Lipomyces starkeyi cells.

Balancing energy production and storage is a fundamental process critical for cellular homeostasis in most eukaryotes that relies on the intimate interplay between mitochondria and lipid droplets. In the oleaginous yeast Lipomyces starkeyi under nitrogen starvation, lipid droplet forms a single giant spherical structure that is easily visible under a light microscope. Currently, how mitochondria behave in L. starkeyi cells undergoing giant lipid droplet formation remains unknown. Here we show that mitochondria transition from fragments to elongated tubules and sheet-like structures that are in close proximity to a giant lipid droplet in nitrogen-depleted L. starkeyi cells. Under the same conditions, mitochondrial degradation and autophagy are strongly suppressed, suggesting that these catabolic events are not required for giant lipid droplet formation. Conversely, carbon-depleted cells suppress mitochondrial elongation and lipid droplet expansion, whereas they promote mitochondrial degradation and autophagy. We propose a potential link of mitochondrial proximity and autophagic suppression to giant lipid droplet formation.

Microplastic exposure linked to accelerated aging and impaired adipogenesis in fat cells

Our research explores the detrimental effects of microplastic (MP) exposure on adipose tissue aging and function, emphasizing the potential health risks associated with environmental pollutants. Utilizing both in vivo and in vitro models, we discovered that MPs accumulate in adipose tissues, leading to cellular senescence, inflammation, and hindered adipogenic differentiation. Notably, our findings demonstrate that MPs prompt an aging response in both epididymal and inguinal white adipose tissue, increase senescence-associated β-galactosidase activity, and upregulate key senescence and inflammatory markers. Furthermore, we show that MPs disrupt normal adipogenic differentiation by reducing lipid droplet formation and downregulating critical adipogenic markers. These insights highlight the urgent need for further investigation into the long-term consequences of MP pollution on biological aging and underscore the importance of developing public health strategies to mitigate these effects.

Diacylglycerol O-acyltransferase 2, a Novel Target of Flavivirus NS2B3 Protease, Promotes Zika Virus Replication by Regulating Lipid Droplet Formation.

Various lipid metabolism-related factors are essential for Zika virus (ZIKV) replication. In this study, we revealed a crucial role of diacylglycerol O-acyltransferase 2 (DGAT2) in ZIKV replication using a short hairpin RNA-based gene knockdown technique. The replication of ZIKV was significantly inhibited by DGAT2 depletion in multiple cell lines and restored by trans-complementation with DGAT2. Mechanistically, DGAT2 is recruited in the viral replication complex by interacting with non-structural (NS) proteins. Among them, both human and murine DGAT2s can be cleaved by NS2B3 at the 122R-R-S124 site. Interestingly, the cleavage product of DGAT2 becomes more stable and is sufficient to promote the lipid droplet (LD) formation independent of its enzymatic activity. This work identifies DGAT2 as a novel target of the viral protease NS2B3 and elucidates that DGAT2 is recruited by viral proteins into the replication complex, thereby playing a proviral role by promoting LD formation, which advances our understanding of host-flavivirus interaction.

Calycosin-7-O-β-D-Glucoside Ameliorates Palmitate-Induced Lipid Accumulation in HT22 Cells.

The pathogenesis of Alzheimer's disease (AD) is complex. Recent research suggests that AD patients have early disorders in brain cholesterol metabolism. Cholesterol and its derivatives accumulate in neurons, leading to p-Tau overproduction and synaptic dysfunction, initiating AD progression. Calycosin-7-O-β-D-glucoside (CG), a distinctive constituent of Astragali Radix, holds a representative position. Many clinical trials have demonstrated that CG can attenuate cerebral ischemia/reperfusion injury and preserve the structural integrity of the blood-brain barrier. However, whether CG alleviates tau-mediated neurodegeneration by increasing cholesterol efflux after lipid accumulation remains unexplored. Ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS) and multivariate data analysis were employed to investigate metabolic changes in HT22 cells induced by sodium palmitate following 24 hours of CG treatment. The potential therapeutic mechanisms of CG on AD were further examined through Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Metabolomic analysis characterized 24 potential biomarkers, revealing that CG could ameliorate cholesterol metabolic pathways. The results of cell experiments revealed that CG can increase the expression of enzyme cholesterol 24-hydroxylase (CYP46A1) (p < 0.05) and the level of 24 hydroxycholesterol (24-OHC) (p < 0.05), reduce the expression of p-Tau (Thr231)/Tau (p < 0.01), inhibit the formation of lipid droplets. CG may inhibit the accumulation of cholesterol and its derivatives in neurons by affecting the CYP46A1-CE-Tau axis, offering a potential therapeutic strategy for AD.

Study on the Mechanism of Guizhi Fuling Decoction in Treating Hyperlipidemia Based on Network Pharmacology and Experimental Methods

Background Hyperlipidemia, caused by abnormal lipid metabolism, has become a significant health concern, especially in younger populations. While statins are commonly used for treatment, they often cause severe side effects with long-term use, leading to increased interest in finding natural alternatives. Purpose This study aimed to investigate how Guizhi Fuling Decoction (GZFL) treats hyperlipidemia using network pharmacology and experimental validation. Materials and Methods Network pharmacology analyzed GZFL’s active components, targets, and treatment mechanisms for hyperlipidemia. Hyperlipidemia rat and high-fat cell models were established. Experimental validation included enzyme-linked immunosorbent assay, Western blot, quantitative polymerase chain reaction, Oil Red O staining, and other methods. Statistical analysis was performed using one-way analysis of variance followed by Tukey’s post hoc test for multiple comparisons. Pearson correlation analysis was used to identify correlations between key protein expressions and lipid levels. Results GZFL comprises 85 active components and targets 218 proteins. Hyperlipidemia involves 3,852 targets, with 175 overlapping targets. Key targets included estrogen receptor 1, prostaglandin-endoperoxide synthase 2, interleukin-6 (IL-6), protein kinase B (AKT) 1, tumor necrosis factor, interleukin-1 beta, peroxisome proliferator-activated receptor gamma (PPARG), tumor protein p53 (TP53), and fructo oligosaccharide (FOS). Major active components were quercetin, phytosterols, kaempferol, and baicalein. Enrichment analysis highlighted processes like lipopolysaccharide response and lipid signaling pathways. Animal studies showed GZFL significantly reduced serum total cholesterol, triglycerides, and low-density lipoprotein cholesterol levels, and increased apolipoprotein A1 ( p &lt; 0.05). Western blot indicated that GZFL influenced AKT, TP53, IL-6, PPARγ expression, and mRNA levels in the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway ( p &lt; 0.01). Serum pharmacology experiments demonstrated GZFL-medicated serum reduced lipid droplet formation in high-fat cell models. Conclusion GZFL contains multiple pharmacologically active components, such as quercetin, phytosterols, and kaempferol, which can influence lipid metabolism. It may exert its effects by regulating proteins like AKT, TP53, IL-6, and PPARγ, participating in lipid and atherosclerosis signaling pathways and the PI3K/AKT/mTOR pathway.

TRPV4 modulation affects mitochondrial parameters in adipocytes and its inhibition upregulates lipid accumulation

Enhanced lipid-droplet formation by adipocytes is a complex process and relevant for obesity. Using knock-out animals, involvement of TRPV4, a thermosensitive ion channel in the obesity has been proposed. However, exact role/s of TRPV4 in adipogenesis and obesity remain unclear and contradictory. Here we used in vitro culture of 3T3L-1 preadipocytes and primary murine-mesenchymal stem cells as model systems, and a series of live-cell-imaging to analyse the direct involvement of TRPV4 exclusively at the adipocytes that are free from other complex signalling as expected in in-vivo condition. Functional TRPV4 is endogenously expressed in pre- and in mature-adipocytes. Pharmacological inhibition of TRPV4 enhances differentiation of preadipocytes to mature adipocytes, increases expression of adipogenic and lipogenic genes, enhances cholesterol, promotes bigger lipid-droplet formation and reduces the lipid droplet temperature. On the other hand, TRPV4 activation enhanced the browning of adipocytes with increased UCP-1 levels. TRPV4 regulates mitochondrial-temperature, Ca2+-load, ATP, superoxides, cardiolipin, membrane potential (ΔΨm), and lipid-mitochondrial contact sites. TRPV4 also regulates the extent of actin fibres, affecting the cells mechanosensing ability. These findings link TRPV4-mediated mitochondrial changes in the context of lipid-droplet formation involved in adipogenesis and confirm the direct involvement of TRPV4 in adipogenesis. These findings may have broad implication in treating adipogenesis and obesity in future.