Neutral Lipid Core Research Articles

Lipid Droplets Big and Small: Basic Mechanisms That Make Them All.

Lipid droplets (LDs) are dynamic storage organelles with central roles in lipid and energy metabolism. They consist of a core of neutral lipids, such as triacylglycerol, which is surrounded by a monolayer of phospholipids and specialized surface proteins. The surface composition determines many of the LD properties, such as size, subcellular distribution, and interaction with partner organelles. Considering the diverse energetic and metabolic demands of various cell types, it is not surprising that LDs are highly heterogeneous within and between cell types. Despite their diversity, all LDs share a common biogenesis mechanism. However, adipocytes have evolved specific adaptations of these basic mechanisms, enabling the regulation of lipid and energy metabolism at both the cellular and organismal levels. Here, we discuss recent advances in the understanding of both the general mechanisms of LD biogenesis and the adipocyte-specific adaptations controlling these fascinating organelles.

Modifying the interfacial dynamics of oleosome (lipid droplet) membrane using curcumin

Cells store energy in lipid droplets, known as oleosomes, which have a neutral lipid core surrounded by a dilatable membrane of phospholipids and proteins. Oleosomes can be loaded with therapeutic lipophilic cargos through their permeable membrane and used as carriers. However, the cargo can also adsorb between the phospholipids and affect the membrane properties. In the present work, we investigated the effect of adsorbed curcumin on the mechanical properties of oleosome membranes using dilatational interfacial rheology (LAOD). The oleosome membrane had a weak-stretchable behavior, while the adsorption of curcumin led to stronger in-plane interactions, which were dependent on curcumin concentration and indicated a glassy-like structure. Our findings showed that adsorbed curcumin molecules can enhance the molecular interactions on the oleosome membrane. This behavior suggests that oleosomes membranes can be modulated by loaded cargo. Understanding cargo and membrane interactions can help to design oleosome-based formulations with tailored mechanical properties for applications.

Cationic Adiposomes as a Delivery System for Neogambogic Acid for the Treatment of Multiple Cancers

AbstractNeogambogic acid (NGA) is a potent antitumor drug but faces significant obstacles to clinical application, including extremely poor water solubility and systemic toxicity. To overcome these obstacles, a newly developed nanoparticle, adiposome, that consists of a neutral lipid core wrapped with a phospholipid‐monolayer membrane, is utilized for the delivery of NGA. In this study, NGA‐loaded cationic adiposomes (NGA‐C‐ADs) are constructed in which NGA is encapsulated within the neutral lipid core and surrounded by phospholipids and a cationic lipid. The concentration of NGA in NGA‐C‐ADs achieved is as high as 1.0 mg mL−1, which is 2 000‐fold higher than in aqueous buffer alone. Moreover, in vitro cell tests revealed that NGA‐C‐ADs exhibited higher cytotoxicity against various cancer cell lines compared to free NGA. In addition, in vivo anti‐tumor animal studies demonstrate that NGA‐C‐ADs effectively inhibit tumor growth in subcutaneous CT26 tumor‐bearing mice and also suppress chemically‐induced hepatocellular carcinoma without obvious toxicity to major organs. These findings suggest that NGA‐C‐ADs hold promise as a potential treatment for multiple cancers.

Perilipins: A family of five fat-droplet storing proteins that play a significant role in fat homeostasis.

Lipid droplets are organelles with unique spherical structures. They consist of a hydrophobic neutral lipid core that varies depending on the cell type and tissue. These droplets are surrounded by phospholipid monolayers, along with heterogeneous proteins responsible for neutral lipid synthesis and metabolism. Additionally, there are specialized lipid droplet-associated surface proteins. Recent evidence suggests that proteins from the perilipin family (PLIN) are associated with the surface of lipid droplets and are involved in their formation. These proteins have specific roles in hepatic lipid droplet metabolism, such as protecting the lipid droplets from lipase action and maintaining a balance between lipid storage and utilization in specific cells. Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by the accumulation of lipid droplets in more than 5% of the hepatocytes. This accumulation can progress into metabolic dysfunction-associated steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. The accumulation of hepatic lipid droplets in the liver is associated with the progression of MASLD and other diseases such as sarcopenic obesity. Therefore, it is crucial to understand the role of perilipins in this accumulation, as these proteins are key targets for developing novel therapeutic strategies. This comprehensive review aims to summarize the structure and characteristics of PLIN proteins, as well as their pathogenic role in the development of hepatic steatosis and fatty liver diseases.

Effects of Recombinant Human Lecithin Cholesterol Acyltransferase on Lipoprotein Metabolism in Humans.

LCAT (lecithin cholesterol acyl transferase) catalyzes the conversion of unesterified, or free cholesterol, to cholesteryl ester, which moves from the surface of HDL (high-density lipoprotein) into the neutral lipid core. As this iterative process continues, nascent lipid-poor HDL is converted to a series of larger, spherical cholesteryl ester-enriched HDL particles that can be cleared by the liver in a process that has been termed reverse cholesterol transport. We conducted a randomized, placebocontrolled, crossover study in 5 volunteers with atherosclerotic cardiovascular disease, to examine the effects of an acute increase of recombinant human (rh) LCAT via intravenous administration (300-mg loading dose followed by 150 mg at 48 hours) on the in vivo metabolism of HDL APO (apolipoprotein)A1 and APOA2, and the APOB100-lipoproteins, very low density, intermediate density, and low-density lipoproteins. As expected, recombinant human LCAT treatment significantly increased HDL-cholesterol (34.9 mg/dL; P≤0.001), and this was mostly due to the increase in cholesteryl ester content (33.0 mg/dL; P=0.014). This change did not affect the fractional clearance or production rates of HDL-APOA1 and HDL-APOA2. There were also no significant changes in the metabolism of APOB100-lipoproteins. Our results suggest that an acute increase in LCAT activity drives greater flux of cholesteryl ester through the reverse cholesterol transport pathway without significantly altering the clearance and production of the main HDL proteins and without affecting the metabolism of APOB100-lipoproteins. Long-term elevations of LCAT might, therefore, have beneficial effects on total body cholesterol balance and atherogenesis.

Yeast perilipin Pet10p/Pln1p interacts with Erg6p in ergosterol metabolism

Lipid droplets (LD) are highly dynamic organelles specialized for the regulation of energy storage and cellular homeostasis. LD consist of a neutral lipid core surrounded by a phospholipid monolayer membrane with embedded proteins, most of which are involved in lipid homeostasis. In this study, we focused on one of the major LD proteins, sterol C24-methyltransferase, encoded by ERG6. We found that the absence of Erg6p resulted in an increased accumulation of yeast perilipin Pet10p in LD, while the disruption of PET10 was accompanied by Erg6p LD over-accumulation. An observed reciprocal enrichment of Erg6p and Pet10p in pet10Δ and erg6Δ mutants in LD, respectively, was related to specific functional changes in the LD and was not due to regulation on the expression level. The involvement of Pet10p in neutral lipid homeostasis was observed in experiments that focused on the dynamics of neutral lipid mobilization as time-dependent changes in the triacylglycerols (TAG) and steryl esters (SE) content. We found that the kinetics of SE hydrolysis was reduced in erg6Δ cells and the mobilization of SE was completely lost in mutants that lacked both Erg6p and Pet10p. In addition, we observed that decreased levels of SE in erg6Δpet10Δ was linked to an overexpression of steryl ester hydrolase Yeh1p. Lipid analysis of erg6Δpet10Δ showed that PET10 deletion altered the composition of ergosterol intermediates which had accumulated in erg6Δ. In conclusion, yeast perilipin Pet10p functionally interacts with Erg6p during the metabolism of ergosterol.

Functionalizing Yeast Lipid Droplets as Versatile Biomaterials.

Lipid droplets (LD) are dynamic cellular organelles of ≈1µm diameter in yeast where a neutral lipid core is surrounded by a phospholipid monolayer and attendant proteins. Beyond the storage of lipids, opportunities for LD engineering remain underdeveloped but they show excellent potential as new biomaterials. In this research, LD from yeast Saccharomyces cerevisiae is engineered to display mCherry fluorescent protein, Halotag ligand binding protein, plasma membrane binding v-SNARE protein, and carbonic anhydrase enzyme via linkage to oleosin, an LD anchoring protein. Each protein-oleosin fusion is coded via a single gene construct. The expressed fusion proteins are specifically displayed on LD and their functions can be assessed within cells by fluorescence confocal microscopy, TEM, and as isolated materials via AFM, flow cytometry, spectrophotometry, and by enzyme activity assay. LD isolated from the cell are shown to be robust and stabilize proteins anchored into them. These engineered LD function as reporters, bind specific ligands, guide LD and their attendant proteins into union with the plasma membrane, and catalyze reactions. Here, engineered LD functions are extended well beyond traditional lipid storage toward new material applications aided by a versatile oleosin platform anchored into LD and displaying linked proteins.

LET-767 determines lipid droplet protein targeting and lipid homeostasis.

Lipid droplets (LDs) are composed of a core of neutral lipids wrapped by a phospholipid (PL) monolayer containing several hundred proteins that vary between different cells or organisms. How LD proteins target to LDs is still largely unknown. Here, we show that RNAi knockdown or gene mutation of let-767, encoding a member of hydroxysteroid dehydrogenase (HSD), displaced the LD localization of three well-known LD proteins: DHS-3 (dehydrogenase/reductase), PLIN-1 (perilipin), and DGAT-2 (diacylglycerol O-acyltransferase 2), and also prevented LD growth in Caenorhabditis elegans. LET-767 interacts with ARF-1 (ADP-ribosylation factor 1) to prevent ARF-1 LD translocation for appropriate LD protein targeting and lipid homeostasis. Deficiency of LET-767 leads to the release of ARF-1, which further recruits and promotes translocation of ATGL-1 (adipose triglyceride lipase) to LDs for lipolysis. The displacement of LD proteins caused by LET-767 deficiency could be reversed by inhibition of either ARF-1 or ATGL-1. Our work uncovers a unique LET-767 for determining LD protein targeting and maintaining lipid homeostasis.

Lipid droplets as substrates for protein phase separation

Membrane-associated protein phase separation plays critical roles in cell biology, driving essential cellular phenomena from immune signaling to membrane traffic. Importantly, by reducing dimensionality from three to two dimensions, lipid bilayers can nucleate phase separation at far lower concentrations compared with those required for phase separation in solution. How might other intracellular lipid substrates, such as lipid droplets, contribute to nucleation of phase separation? Distinct from bilayer membranes, lipid droplets consist of a phospholipid monolayer surrounding a core of neutral lipids, and they are energy storage organelles that protect cells from lipotoxicity and oxidative stress. Here, we show that intrinsically disordered proteins can undergo phase separation on the surface of synthetic and cell-derived lipid droplets. Specifically, we find that the model disordered domains FUS LC and LAF-1 RGG separate into protein-rich and protein-depleted phases on the surfaces of lipid droplets. Owing to the hydrophobic nature of interactions between FUS LC proteins, increasing ionic strength drives an increase in its phase separation on droplet surfaces. The opposite is true for LAF-1 RGG, owing to the electrostatic nature of its interprotein interactions. In both cases, protein-rich phases on the surfaces of synthetic and cell-derived lipid droplets demonstrate molecular mobility indicative of a liquid-like state. Our results show that lipid droplets can nucleate protein condensates, suggesting that protein phase separation could be key in organizing biological processes involving lipid droplets.

PIM1 drives lipid droplet accumulation to promote proliferation and survival in prostate cancer

Lipid droplets (LDs) are dynamic organelles with a neutral lipid core surrounded by a phospholipid monolayer. Solid tumors exhibit LD accumulation, and it is believed that LDs promote cell survival by providing an energy source during energy deprivation. However, the precise mechanisms controlling LD accumulation and utilization in prostate cancer are not well known. Here, we show peroxisome proliferator-activated receptor α (PPARα) acts downstream of PIM1 kinase to accelerate LD accumulation and promote cell proliferation in prostate cancer. Mechanistically, PIM1 inactivates glycogen synthase kinase 3 beta (GSK3β) via serine 9 phosphorylation. GSK3β inhibition stabilizes PPARα and enhances the transcription of genes linked to peroxisomal biogenesis (PEX3 and PEX5) and LD growth (Tip47). The effects of PIM1 on LD accumulation are abrogated with GW6471, a specific inhibitor for PPARα. Notably, LD accumulation downstream of PIM1 provides a significant survival advantage for prostate cancer cells during nutrient stress, such as glucose depletion. Inhibiting PIM reduces LD accumulation in vivo alongside slow tumor growth and proliferation. Furthermore, TKO mice, lacking PIM isoforms, exhibit suppression in circulating triglycerides. Overall, our findings establish PIM1 as an important regulator of LD accumulation through GSK3β-PPARα signaling axis to promote cell proliferation and survival during nutrient stress.

Differential lipid analysis of oxaliplatin-sensitive and resistant HCT116 cells reveals different levels of drug-induced lipid droplet formation.

Lipid droplets (LDs) are intracellular storage vesicles composed of a neutral lipid core surrounded by a glycerophospholipid membrane. LD accumulation is associated with different stages of cancer progression and stress responses resulting from chemotherapy. In previous work, a novel dual nano-electrospray ionization source and data-dependent acquisition method for measuring the relative abundances of lipid species between two extracts were described and validated. Here, this same source and method were used to determine if oxaliplatin-sensitive and resistant cells undergo similar lipid profile changes, with the goal of identifying potential signatures that could predict the effectiveness of an oxaliplatin-containing treatment. Oxaliplatin is commonly used in the treatment of colorectal cancer. When compared to a no-drug control, oxaliplatin dosing caused significant increases in triglyceride (TG) and cholesterol ester (CE) species. These increases were more pronounced in the oxaliplatin-sensitive cells than in oxaliplatin-resistant cells. The increased neutral lipid abundance correlated with LD formation, as confirmed by confocal micrographs of Nile Red-stained cells. Untargeted proteomic analyses also support LD formation after oxaliplatin treatment, with an increased abundance of LD-associated proteins in both the sensitive and resistant cells.

Concept of lipid droplet biogenesis

Lipid droplets (LD) are functionally conserved fat storage organelles found in all cell types. LDs have a unique structure comprising of a hydrophobic core of neutral lipids (fat), triacylglycerol (TAG) and cholesterol esters (CE) surrounded by a phospholipid monolayer. LD surface is decorated by a multitude of proteins and enzymes rendering this compartment functional. Accumulating evidence suggests that LDs originate from discrete ER-subdomains, demarcated by the lipodystrophy protein seipin, however, the mechanisms of which are not well understood. LD biogenesis factors together with biophysical properties of the ER membrane orchestrate spatiotemporal regulation of LD nucleation and growth at specific ER subdomains in response to metabolic cues. Defects in LD formation manifests in several human pathologies, including obesity, lipodystrophy, ectopic fat accumulation, and insulin resistance. Here, we review recent advances in understanding the molecular events during initial stages of eukaryotic LD assembly and discuss the critical role of factors that ensure fidelity of this process.

Construction and application of artificial lipoproteins using adiposomes

Lipoproteins are complex particles comprised of a neutral lipid core wrapped with a phospholipid monolayer membrane and apolipoproteins on the membrane, which is closely associated with metabolic diseases. To facilitate the elucidation of its formation and dynamics, as well as its applications, we developed an in vitro system in which adiposomes, consisting of a hydrophobic core encircled by a monolayer-phospholipid membrane, were engineered into artificial lipoproteins (ALPs) by recruiting one or more kinds of apolipoproteins, for example, apolipoprotein (Apo) A-I, ApoE, ApoA-IV, and ApoB. In vitro and in vivo studies demonstrated the stability and biological activity of ALPs derived from adiposomes, which resembles native lipoproteins. Of note, adiposomes bearing ApoE were internalized via clathrin-mediated endocytosis following LDLR binding and were delivered to lysosomes. On the other hand, adiposomes bearing ApoA-IV mimicked the existing form of endogenous ApoA-IV and exhibited significant improvement in glucose tolerance in mice. In addition, the construction process was simple, precise, reproducible, as well as easy to adjust for mass production. With this experimental system, different apolipoproteins can be recruited to build ALPs for some biological goals and potential applications in biomedicine.

Ostwald Ripening of Triacylglycerol Droplets Embedded in Glass-Supported Phospholipid Bilayers.

Lipid droplets are fat storage organelles that consist of a neutral lipid core surrounded by a phospholipid monolayer. Because of their important biological functions, reconstituting model lipid droplets in synthetic phospholipid membranes is of great interest. In the present study, we investigated the incorporation of triacylglycerol droplets into glass-supported phospholipid bilayers by using fluorescence microscopy. We adsorbed triolein emulsions onto a glass surface that was partially covered with planar bilayers. After adsorption, triolein droplets were found to be immobilized in the bilayer membrane. The volume of each bound droplet varied over time. Large droplets grew, whereas small droplets shrank. Additionally, data on fluorescence recovery after photobleaching obtained for a phospholipid probe indicate that phospholipids on and near triolein droplets were fully mobile. Furthermore, photobleaching data obtained for a triacylglycerol probe indicate that triolein molecules diffused between different droplets along the planar bilayer. These results demonstrate Ostwald ripening, where triolein molecules in a small droplet dissolved in the bilayer, diffused laterally, and eventually bound to the interfaces of larger droplets. We investigated the ripening rate by using the average of the cube root of the fluorescence emission obtained for individual droplets. The ripening slowed after the addition of trilinolein to the triolein phase. Finally, we investigated the time dependence of the size distributions of the triolein droplets. The distribution was initially nearly unimodal and subsequently became bimodal.

Tapping lipid droplets: A rich fat diet of intracellular bacterial pathogens.

Lipid droplets (LDs) are dynamic and versatile organelles present in most eukaryotic cells. LDs consist of a hydrophobic core of neutral lipids, a phospholipid monolayer coat, and a variety of associated proteins. LDs are formed at the endoplasmic reticulum and have diverse roles in lipid storage, energy metabolism, membrane trafficking, and cellular signaling. In addition to their physiological cellular functions, LDs have been implicated in the pathogenesis of several diseases, including metabolic disorders, cancer, and infections. A number of intracellular bacterial pathogens modulate and/or interact with LDs during host cell infection. Members of the genera Mycobacterium, Legionella, Coxiella, Chlamydia, and Salmonella exploit LDs as a source of intracellular nutrients and membrane components to establish their distinct intracellular replicative niches. In this review, we focus on the biogenesis, interactions, and functions of LDs, as well as on their role in lipid metabolism of intracellular bacterial pathogens.

Perilipin 3 promotes the formation of membrane domains enriched in diacylglycerol and lipid droplet biogenesis proteins.

Lipid droplets (LDs) serve as intracellular stores of energy-rich neutral lipids. LDs form at discrete sites in the endoplasmic reticulum (ER) and they remain closely associated with the ER during lipogenic growth and lipolytic consumption. Their hydrophobic neutral lipid core is covered by a monolayer of phospholipids, which harbors a specific set of proteins. This LD surface is coated and stabilized by perilipins, a family of soluble proteins that specifically target LDs from the cytosol. We have previously used chimeric fusion proteins between perilipins and integral ER membrane proteins to test whether proteins that are anchored to the ER bilayer could be dragged onto the LD monolayer. Expression of these chimeric proteins induces repositioning of the ER membrane around LDs. Here, we test the properties of membrane-anchored perilipins in cells that lack LDs. Unexpectedly, membrane-anchored perilipins induce expansion and vesiculation of the perinuclear membrane resulting in the formation of crescent-shaped membrane domains that harbor LD-like properties. These domains are stained by LD-specific lipophilic dyes, harbor LD marker proteins, and they transform into nascent LDs upon induction of neutral lipid synthesis. These ER domains are enriched in diacylglycerol (DAG) and in ER proteins that are important for early steps of LD biogenesis, including seipin and Pex30. Formation of the domains in vivo depends on DAG levels, and we show that perilipin 3 (PLIN3) binds to liposomes containing DAG in vitro. Taken together, these observations indicate that perilipin not only serve to stabilize the surface of mature LDs but that they are likely to exert a more active role in early steps of LD biogenesis at ER subdomains enriched in DAG, seipin, and neutral lipid biosynthetic enzymes.

Lipid Droplets from Plants and Microalgae: Characteristics, Extractions, and Applications.

Plant and algal LDs are gaining popularity as a promising non-chemical technology for the production of lipids and oils. In general, these organelles are composed of a neutral lipid core surrounded by a phospholipid monolayer and various surface-associated proteins. Many studies have shown that LDs are involved in numerous biological processes such as lipid trafficking and signaling, membrane remodeling, and intercellular organelle communications. To fully exploit the potential of LDs for scientific research and commercial applications, it is important to develop suitable extraction processes that preserve their properties and functions. However, research on LD extraction strategies is limited. This review first describes recent progress in understanding the characteristics of LDs, and then systematically introduces LD extraction strategies. Finally, the potential functions and applications of LDs in various fields are discussed. Overall, this review provides valuable insights into the properties and functions of LDs, as well as potential approaches for their extraction and utilization. It is hoped that these findings will inspire further research and innovation in the field of LD-based technology.

Cholesterol esters lipid droplets biogenesis.

Lipid droplets (LDs) are nearly universal organelles, present in most of the eukaryotic cells. As storage organelles, they are the cornerstone of lipid storage and homeostasis. They consist of a neutral lipid core surrounded by a phospholipid and protein monolayer. Triacylglycerols (TGs) and Cholesteryl Esters (CEs) are the two most abundant neutral lipids. While TG melts at 4°C, CE melts at 44°C, raising the question of how cells manage to package CE in micron-sized LDs. In order to understand the biogenesis of CE-rich LDs, we first took advantage of in-vitro systems, such as Giant Unilamellar Vesicles (GUVs) and Droplet Embedded Vesicles (DEVs), to better study and predict the behaviour of CE molecules confined in a membrane bilayer. Then, we conducted cell experiments which agreed with our in-vitro models. Our studies revealed that CEs form supercooled droplets when representing more than 20% of the LDs’ lipids and, in particular, liquid-crystalline phases if above 90%. In model bilayers, CE condensed and nucleated as droplets when a critical CE/Phospholipids ratio was reached. We also found that this threshold was reduced in the presence of TG. Accordingly, CE LDs nucleation was strongly reduced upon inhibition of TG synthesis in cells. Our data point to a unique model whereby TG catalyzes the nucleation of CE LDs.

Differential lipid interaction of the C-terminus and full length perilipin 3.

Lipid Droplets (LDs) are highly complex, dynamic organelles critical for cellular energy regulation. They are found in almost all cell types. The structure of LDs consists of a neutral lipid core surrounded by a phospholipid-protein monolayer instead of a lipid-protein bilayer. This sets them apart from all other intracellular organelles. It is well known that the LD monolayer contains predominantly phosphatidylcholine (PC), significant amounts of phosphatidylethanolamine (PE), and other lipid species in smaller amounts. Because of LD structural complexity and heterogeneity within a cell, it is critical to inquire how each lipid component affects LD function and its ability to recruit binding proteins. Cytosolic LD binding proteins contain complex physical structures such as amphipathic α-helices some of which can form helix bundles. Perilipins are the most abundant LD-associated protein family expressed in humans. An amphipathic α-helix bundle is found at the C-terminus of perilipins 2, 3, and 5. This α-helix is similar to the well-known lipid-binding domains of the apolipoproteins apoE and apoLp-III. In this study, we show that the C-terminus of perilipin 3 may help the protein to bind to the LDs after the initial localization from the N-terminal 11-mer repeat region. We use pendant drop tensiometry to get a measure of the recruitment and insertion of perilipin 3 to model LD lipid monolayers at aqueous-phospholipid-oil interfaces. We identified a higher insertion of an unsaturated PC monolayer for both the full length and the C-terminus of perilipin 3 in this interface. By adding PE to the monolayer, we identify an increase in the insertion of the C-terminus but not for the full-length protein.

Lipid droplet synthesis is associated with angiogenesis in mouse ovarian follicles†.

Lipid droplets (LDs) are endoplasmic reticulum (ER)-derived organelles comprising a core of neutral lipids surrounded by a phospholipid monolayer. Lipid droplets play important roles in lipid metabolism and energy homeostasis. Mammalian ovaries have been hypothesized to use neutral lipids stored in LDs to produce the hormones and nutrients necessary for rapid follicular development; however, our understanding of LD synthesis remains incomplete. In this study, we generated transgenic reporter mice that express mCherry fused to HPos, a minimal peptide that localizes specifically to nascent LDs synthesized at the ER. With this tool for visualizing initial LD synthesis in ovaries, we found that LDs are synthesized continuously in theca cells but rarely in inner granulosa cells (Gc) during early follicular development. Administration of exogenous gonadotropin enhances LD synthesis in the Gc, suggesting that LD synthesis is hormonally regulated. In contrast, we observed copious LD synthesis in the corpus luteum, and excessive LDs accumulation in atretic follicles. Furthermore, we demonstrated that LD synthesis is synchronized with angiogenesis around the follicle and that suppressing angiogenesis caused defective LD biosynthesis in developing follicles. Overall, our study is the first to demonstrate a spatiotemporally regulated interplay between LD synthesis and neovascularization during mammalian follicular development.