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Food Research International (Ottawa,... Jul 2024Spatiotemporal assessment of lipid and protein oxidation is key for understanding quality deterioration in emulsified food products containing polyunsaturated fatty...
Spatiotemporal assessment of lipid and protein oxidation is key for understanding quality deterioration in emulsified food products containing polyunsaturated fatty acids. In this work, we first mechanistically validated the use of the lipid oxidation-sensitive fluorophore BODIPY 665/676 as a semi-quantitative marker for local peroxyl radical formation. Next, we assessed the impact of microfluidic and colloid mill emulsification (respectively producing mono- and polydisperse droplets) on local protein and lipid oxidation kinetics in whey protein isolate (WPI)-stabilized emulsions. We further used BODIPY 581/591 C11 and CAMPO-AFDye 647 as colocalisation markers for lipid and protein oxidation. The polydisperse emulsions showed an inverse relation between droplet size and lipid oxidation rate. Further, we observed less protein and lipid oxidation occurring in similar sized droplets in monodisperse emulsions. This observation was linked to more heterogeneous protein packing at the droplet surface during colloid mill emulsification, resulting in larger inter-droplet heterogeneity in both protein and lipid oxidation. Our findings indicate the critical roles of emulsification methods and droplet sizes in understanding and managing lipid oxidation.
Topics: Whey Proteins; Emulsions; Oxidation-Reduction; Particle Size; Boron Compounds; Kinetics; Peroxides; Lipids
PubMed: 38823851
DOI: 10.1016/j.foodres.2024.114341 -
Cell May 2024Dolichol is a lipid critical for N-glycosylation as a carrier for activated sugars and nascent oligosaccharides. It is commonly thought to be directly produced from...
Dolichol is a lipid critical for N-glycosylation as a carrier for activated sugars and nascent oligosaccharides. It is commonly thought to be directly produced from polyprenol by the enzyme SRD5A3. Instead, we found that dolichol synthesis requires a three-step detour involving additional metabolites, where SRD5A3 catalyzes only the second reaction. The first and third steps are performed by DHRSX, whose gene resides on the pseudoautosomal regions of the X and Y chromosomes. Accordingly, we report a pseudoautosomal-recessive disease presenting as a congenital disorder of glycosylation in patients with missense variants in DHRSX (DHRSX-CDG). Of note, DHRSX has a unique dual substrate and cofactor specificity, allowing it to act as a NAD-dependent dehydrogenase and as a NADPH-dependent reductase in two non-consecutive steps. Thus, our work reveals unexpected complexity in the terminal steps of dolichol biosynthesis. Furthermore, we provide insights into the mechanism by which dolichol metabolism defects contribute to disease.
PubMed: 38821050
DOI: 10.1016/j.cell.2024.04.041 -
Frontiers in Cell and Developmental... 2024Over the past 10 years, the biological role of lipid droplets (LDs) has gained significant attention in the context of both physiological and pathological conditions.... (Review)
Review
Over the past 10 years, the biological role of lipid droplets (LDs) has gained significant attention in the context of both physiological and pathological conditions. Considerable progress has been made in elucidating key aspects of these organelles, yet much remains to be accomplished to fully comprehend the myriad functions they serve in the progression of hepatic tumors. Our current perception is that LDs are complex and active structures managed by a distinct set of cellular processes. This understanding represents a significant paradigm shift from earlier perspectives. In this review, we aim to recapitulate the function of LDs within the liver, highlighting their pivotal role in the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) (Hsu and Loomba, 2024) and their contribution to the progression towards more advanced pathological stages up to hepatocellular carcinoma (HC) (Farese and Walther, 2009). We are aware of the molecular complexity and changes occurring in the neoplastic evolution of the liver. Our attempt, however, is to summarize the most important and recent roles of LDs across both healthy and all pathological liver states, up to hepatocarcinoma. For more detailed insights, we direct readers to some of the many excellent reviews already available in the literature (Gluchowski et al., 2017; Hu et al., 2020; Seebacher et al., 2020; Paul et al., 2022).
PubMed: 38818407
DOI: 10.3389/fcell.2024.1404006 -
Biomedicine & Pharmacotherapy =... Jul 2024Hyperlipidemia-induced osteoporosis is marked by increased bone marrow adiposity, and treatment with statins for hyperlipidemia often leads to new-onset osteoporosis....
Hyperlipidemia-induced osteoporosis is marked by increased bone marrow adiposity, and treatment with statins for hyperlipidemia often leads to new-onset osteoporosis. Endosome-associated trafficking regulator 1 (ENTR1) has been found to interact with different proteins in pathophysiology, but its exact role in adipogenesis is not yet understood. This research aimed to explore the role of ENTR1 in adipogenesis and to discover a new small molecule that targets ENTR1 for evaluating its effectiveness in treating hyperlipidemia-induced osteoporosis. We found that ENTR1 expression increased during the adipogenesis of bone marrow mesenchymal cells (BMSCs). ENTR1 gain- and loss-of-function assays significantly enhanced lipid droplets formation. Mechanistically, ENTR1 binds peroxisome proliferator-activated receptor γ (PPARγ) and enhances its expression, thereby elevating adipogenic markers including C/EBPα and LDLR. Therapeutically, AN698/40746067 attenuated adipogenesis by targeting ENTR1 to suppress PPARγ. In vivo, AN698/40746067 reduced bone marrow adiposity and bone loss, as well as prevented lipogenesis-related obesity, inflammation, steatohepatitis, and abnormal serum lipid levels during hyperlipidemia. Together, these findings suggest that ENTR1 facilitates adipogenesis by PPARγ involved in BMSCs' differentiation, and targeted inhibition of ENTR1 by AN698/40746067 may offer a promising therapy for addressing lipogenesis-related challenges and alleviating osteoporosis following hyperlipidemia.
Topics: Animals; Hyperlipidemias; Osteoporosis; PPAR gamma; Adipogenesis; Adiposity; Mice, Inbred C57BL; Mice; Mesenchymal Stem Cells; Male; Bone Marrow; Endosomal Sorting Complexes Required for Transport
PubMed: 38810405
DOI: 10.1016/j.biopha.2024.116843 -
Science Advances May 2024Lipid droplets (LDs) comprise a triglyceride core surrounded by a lipid monolayer enriched with proteins, many of which function in LD homeostasis. How proteins are...
Lipid droplets (LDs) comprise a triglyceride core surrounded by a lipid monolayer enriched with proteins, many of which function in LD homeostasis. How proteins are targeted to the growing LD is still unclear. Rab1b, a GTPase regulating secretory transport, was recently associated with targeting proteins to LDs in a Drosophila RNAi screen. LD formation was prevented in human hepatoma cells overexpressing dominant-negative Rab1b. We thus hypothesized that Rab1b recruits lipid-synthesizing enzymes, facilitating LD growth. Here, FRET between diacylglycerol acyltransferase 2 (DGAT2) and Rab1b and activity mutants of the latter demonstrated that Rab1b promotes DGAT2 ER to the LD surface redistribution. Last, alterations in LD metabolism and DGAT2 redistribution, consistent with Rab1b activity, were caused by mutations in the Rab1b-GTPase activating protein TBC1D20 in Warburg Micro syndrome (WARBM) model mice fibroblasts. These data contribute to our understanding of the mechanism of Rab1b in LD homeostasis and WARBM, a devastating autosomal-recessive disorder caused by mutations in TBC1D20.
Topics: Lipid Droplets; Animals; Humans; rab1 GTP-Binding Proteins; Diacylglycerol O-Acyltransferase; Mice; Endoplasmic Reticulum; Mutation; Lipid Metabolism; GTPase-Activating Proteins
PubMed: 38809969
DOI: 10.1126/sciadv.ade7753 -
Journal of Biomedical Research Feb 2024As a potential endocrine-disrupting chemical, bisphenol F (BPF) may cause nonalcoholic fatty liver disease (NAFLD)-like changes, but the mechanisms underpinning its...
As a potential endocrine-disrupting chemical, bisphenol F (BPF) may cause nonalcoholic fatty liver disease (NAFLD)-like changes, but the mechanisms underpinning its pathogenesis as well as the intervention strategies remain poorly understood. Using the electron microscopy technology, along with LipidTOX Deep Red neutral and Bodipy 493/503 staining assays, we observed that BPF treatment elicited a striking accumulation of lipid droplets in HepG2 cells, accompanied by an increased total level of triglycerides. At the molecular level, the lipogenesis-associated mRNAs and proteins, including acetyl-CoA carboxylase, fatty acid synthase, stearoyl-CoA desaturase-1, peroxisome proliferator-activated receptor gamma, and CCAAT-enhancer-binding proteins, increased significantly the AMP-activated protein kinase (AMPK)-mammalian target of rapamycin (mTOR) signaling regulation in both and studies. Furthermore, the immunofluorescence results also showed the robust lipogenesis induced by BPF, evident in its ability to promote the translocation of sterol regulatory element-binding protein-1c from the cytoplasm to the nuclei. To investigate the intervention strategies for BPF-induced NAFLD-like changes, we demonstrated that bellidifolin, isolated and purified from , significantly attenuated BPF-induced lipid droplet deposition in HepG2 cell and NAFLD-like changes in mice by blocking the expression of lipogenesis-associated proteins. Therefore, the present study elucidates the mechanisms underlying BPF-induced lipid accumulation in HepG2 cells, while also highlighting the potential of bellidifolin to mitigate BPF-induced NAFLD-like changes.
PubMed: 38808572
DOI: 10.7555/JBR.37.20230169 -
Contact (Thousand Oaks (Ventura County,... 2024One means by which cells reutilize neutral lipids stored in lipid droplets is to degrade them by autophagy. This process involves spartin, mutations of which cause the...
One means by which cells reutilize neutral lipids stored in lipid droplets is to degrade them by autophagy. This process involves spartin, mutations of which cause the rare inherited disorder Troyer syndrome (or spastic paraplegia-20, SPG20). A recently published paper from the team led by Karin Reinsich (Yale) suggests that the molecular function of spartin and its unique highly conserved "senescence" domain is as a lipid transfer protein. Spartin binds to and transfers all lipid species found in lipid droplets, from phospholipids to triglycerides and sterol esters. This lipid transfer activity correlates with spartin's ability to sustain lipid droplet turnover. The senescence domain poses an intriguing question around the wide range of its cargoes, but intriguingly it has yet to yield up its secrets because attempts at crystallization failed and AlphaFold's prediction is unconvincing.
PubMed: 38808280
DOI: 10.1177/25152564241255782 -
Orphanet Journal of Rare Diseases May 2024Biallelic pathogenic variants of LARS1 cause infantile liver failure syndrome type 1 (ILFS1), which is characterized by acute hepatic failure with steatosis in infants....
BACKGROUND
Biallelic pathogenic variants of LARS1 cause infantile liver failure syndrome type 1 (ILFS1), which is characterized by acute hepatic failure with steatosis in infants. LARS functions as a protein associated with mTORC1 and plays a crucial role in amino acid-triggered mTORC1 activation and regulation of autophagy. A previous study demonstrated that larsb-knockout zebrafish exhibit conditions resembling ILFS. However, a comprehensive analysis of larsb-knockout zebrafish has not yet been performed because of early mortality.
METHODS
We generated a long-term viable zebrafish model carrying a LARS1 variant identified in an ILFS1 patient (larsb-I451F zebrafish) and analyzed the pathogenesis of the affected liver of ILFS1.
RESULTS
Hepatic dysfunction is most prominent in ILFS1 patients during infancy; correspondingly, the larsb-I451F zebrafish manifested hepatic anomalies during developmental stages. The larsb-I451F zebrafish demonstrates augmented lipid accumulation within the liver during autophagy activation. Inhibition of DGAT1, which converts fatty acids to triacylglycerols, improved lipid droplets in the liver of larsb-I451F zebrafish. Notably, treatment with an autophagy inhibitor ameliorated hepatic lipid accumulation in this model.
CONCLUSIONS
Our findings suggested that enhanced autophagy caused by biallelic LARS1 variants contributes to ILFS1-associated hepatic dysfunction. Furthermore, the larsb-I451F zebrafish model, which has a prolonged survival rate compared with the larsb-knockout model, highlights its potential utility as a tool for investigating the pathophysiology of ILFS1-associated liver dysfunction.
Topics: Animals; Zebrafish; Autophagy; Fatty Liver; Liver; Humans; Disease Models, Animal
PubMed: 38807157
DOI: 10.1186/s13023-024-03226-6 -
Biomedicine & Pharmacotherapy =... Jul 2024The overstoring of surplus calories in mature adipocytes causes obesity and abnormal metabolic activity. The anti-obesity effect of a Celosia cristata (CC) total flower...
BACKGROUND
The overstoring of surplus calories in mature adipocytes causes obesity and abnormal metabolic activity. The anti-obesity effect of a Celosia cristata (CC) total flower extract was assessed in vitro, using 3T3-L1 pre-adipocytes and mouse adipose-derived stem cells (ADSCs), and in vivo, using high-fat diet (HFD)-treated C57BL/6 male mice.
METHODS
CC extract was co-incubated during adipogenesis in both 3T3-L1 cells and ADSCs. After differentiation, lipid droplets were assessed by oil red O staining, adipogenesis and lipolytic factors were evaluated, and intracellular triglyceride and glycerol concentrations were analyzed. For in vivo experiments, histomorphological analysis, mRNA expression levels of adipogenic and lipolytic factors in adipose tissue, blood plasma analysis, metabolic profiles were investigated.
RESULTS
CC treatment significantly prevented adipocyte differentiation and lipid droplet accumulation, reducing adipogenesis-related factors and increasing lipolysis-related factors. Consequently, the intracellular triacylglycerol content was diminished, whereas the glycerol concentration in the cell supernatant increased. Mice fed an HFD supplemented with the CC extract exhibited decreased HFD-induced weight gain with metabolic abnormalities such as intrahepatic lipid accumulation and adipocyte hypertrophy. Improved glucose utilization and insulin sensitivity were observed, accompanied by the amelioration of metabolic disturbances, including alterations in liver enzymes and lipid profiles, in CC-treated mice. Moreover, the CC extract helped restore the disrupted energy metabolism induced by the HFD, based on a metabolic animal monitoring system.
CONCLUSION
This study suggests that CC total flower extract is a potential natural herbal supplement for the prevention and management of obesity.
Topics: Animals; Plant Extracts; Male; Mice; 3T3-L1 Cells; Mice, Inbred C57BL; Anti-Obesity Agents; Flowers; Adipogenesis; Obesity; Diet, High-Fat; Adipocytes; Celosia; Adipose Tissue; Lipid Metabolism; Lipolysis; Cell Differentiation
PubMed: 38805969
DOI: 10.1016/j.biopha.2024.116799 -
ELife May 2024is a powerful model to study how lipids affect spermatogenesis. Yet, the contribution of neutral lipids, a major lipid group which resides in organelles called lipid...
is a powerful model to study how lipids affect spermatogenesis. Yet, the contribution of neutral lipids, a major lipid group which resides in organelles called lipid droplets (LD), to sperm development is largely unknown. Emerging evidence suggests LD are present in the testis and that loss of neutral lipid- and LD-associated genes causes subfertility; however, key regulators of testis neutral lipids and LD remain unclear. Here, we show LD are present in early-stage somatic and germline cells within the testis. We identified a role for triglyceride lipase () in regulating testis LD, and found that whole-body loss of leads to defects in sperm development. Importantly, these represent cell-autonomous roles for in regulating testis LD and spermatogenesis. Because lipidomic analysis of mutants revealed excess triglyceride accumulation, and spermatogenic defects in mutants were rescued by genetically blocking triglyceride synthesis, our data suggest that -mediated regulation of triglyceride influences sperm development. This identifies triglyceride as an important neutral lipid that contributes to sperm development, and reveals a key role for in regulating testis triglyceride levels during spermatogenesis.
Topics: Spermatogenesis; Animals; Male; Triglycerides; Drosophila Proteins; Testis; Drosophila melanogaster; Lipase; Lipid Droplets; Spermatozoa
PubMed: 38805376
DOI: 10.7554/eLife.87523