Number Of Lipid Droplets Research Articles

Effects of different water temperatures on the ovarian development and biochemical composition of Portunus trituberculatus after mating (Decapoda, Portunidae)

Abstract This study investigated the effects of different water temperatures (20, 23, 26 and 29°C) on the ovarian development and biochemical composition of Portunus trituberculatus (a swimming crab) after mating. The results showed that the higher the water temperature was, the faster the ovarian development, especially the GSI in the 29°C group was significantly higher than that in the 20°C and 23°C groups (). The hepatosomatic index (HSI) decreased with increasing water temperature, but there was no significant difference between the groups at different water temperatures (). The muscle yield (MY) was basically maintained at approximately 34%. The condition factor (CF) of the crab reached 0.62 in the 29°C group, which was significantly higher than that in the 20°C and 23°C groups (). Histological observation revealed that the number of lipid droplets and the degree of homogenization of yolk granules in ovarian oocytes gradually increased with the increase of the water temperature. From the perspective of conventional biochemical composition, the moisture and crude protein contents in muscle and the crude fat content in hepatopancreas did not change much among the groups, but the crude protein content in the ovary of the 29°C group was as high as 24.65%, which was significantly higher than that in the other three groups (). In terms of fatty acid composition, there was little difference in the fatty acid content in the ovaries of the different water temperature groups. The contents of C22 : 2n6 and C18 : 3n3 in polyunsaturated fatty acids were significantly higher in the 29°C group than in the other three groups (). In the hepatopancreas, the contents of C22 : 5n3 (DPA) and C22 : 6n3 (DHA) in the 20°C group were the lowest, 0.07% and 0.15%, respectively, which were significantly lower values than in the 29°C group (). The change of amino acid content is mainly reflected in ovarian tissues, showing a gradual upward trend as a whole. Furthermore, the essential amino acid score (EAAS) and average score of the two tissues in the 20°C and 23°C groups were relatively close, and both reached the highest score in the 29°C group. Overall, with increasing water temperature, the rate of ovarian development significantly accelerated, and the nutritional quality of the tissues improved in these swimming crabs.

Feline cumulus cells and oocytes show massive accumulation of lipid droplets and upregulation of PLIN2 expression after in vitro maturation

This study investigates lipid content and expression of genes involved in lipid metabolism in feline cumulus cells and oocytes before and after in vitro maturation (IVM). Domestic cats represent valuable models in reproductive research, yet the efficiency of in vitro embryo production remains suboptimal, with contributing factors still under investigation. We characterized lipid droplets (LDs) in oocytes collected from adult queens, both before and after IVM, using confocal microscopy with Bodipy 493/503 staining. We also quantified the expression of four genes involved in regulation of lipid metabolism. Our findings revealed a substantial accumulation of LDs and a significant upregulation of PLIN2 expression in both cumulus cells and oocytes following IVM. The number and total area of LDs and fluorescence intensity increased markedly in oocytes at the MII stage, while the average LD diameter decreased. Similarly, cumulus cells showed an increase in number and total area of LDs post-IVM, suggesting their involvement in oocyte maturation by modulating lipid homeostasis. This study presents the first detailed characterization of lipid droplet dynamics in feline oocytes and cumulus cells, providing insights into metabolic processes during IVM, which are critical for optimizing assisted reproductive technologies in felids.

Lipin1 prevents ischemic heart disease by regulating lipid homeostasis

Abstract Background Lipid metabolism plays a crucial role in the pathophysiology of cardiovascular diseases. Lipin1 plays a pivotal role in lipid metabolism regulation. In the nucleus, Lipin1 acts as a transcriptional co-stimulatory molecule, interacting with peroxisome proliferator–activated receptor–gamma coactivator 1 alpha (PGC1α) and peroxisome proliferator–activated receptor alpha (PPARα). In the cytoplasm, Lipin1 functions as a phosphatidate phosphatase, converting phosphatidic acid to diacylglycerol to regulate lipid metabolism. Low expression of Lipin1 has been implicated in the severity of cardiac dysfunction in mice. Purpose This study aimed to investigate the role of Lipin1 in the cardiac remodeling after myocardial infarction (MI), revealing its impact on lipid metabolism and molecular pathway associated with cardiac dysfunction. Methods Two types of transgenic mice, cardiomyocyte-specific Lipin1 knockout (cKO) and overexpression (cOE) mice were used in this study. Eight to ten-week-old male mice were subjected to MI by coronary artery ligation. Cardiac lipid droplets were quantified, and triacylglycerol and free fatty acid levels were measured one week after MI surgery. Four weeks after MI, cardiac morphology and function were evaluated using echocardiography, alongside measurements of body weight (BW) and heart weight (HW). Additionally, gene expression analysis and histological evaluation were conducted to assess fatty acid metabolism, cardiac fibrosis, inflammation, and oxidative damage. Results Before MI surgery, there were no differences in HW/BW ratio, left ventricular end-diastolic diameter (LVDd) or LV fractional area change (LVFAC) among cKO/ cOE mice and their littermate controls. After MI, cKO mice exhibited significant cardiac dysfunction with larger LVDd, lower LVFAC and increased HW/BW ratio compared to littermate controls. This was accompanied by exacerbated cardiac fibrosis, increased inflammation, and augmented reactive oxygen species accumulation compared with their controls. Conversely, cOE mice displayed improved LVFAC, reduced cardiac fibrosis, inflammation, and reactive oxygen species accumulation compared to their littermate controls. Notably, the transgene of Lipin1 induced changes in the number of cardiac lipid droplets (LDs). cKO mice hearts showed a reduction in cardiac LDs with decreased levels of triacylglycerol and free fatty acids compared to the littermate controls. In contrast, cOE mice displayed increased cardiac LDs and upregulated expression of fatty acid metabolism–related genes after MI. Conclusion These results suggested that Lipin1 has a protective role against ischemic injury through controlling lipid metabolism in ischemic cardiomyocytes. Thus, Lipin1 emerges as a potential therapeutic target for myocardial infarction.

Adipose tissue/ heart lipid transport determines cardiac diastolic function

Abstract Introduction Heart failure with preserved ejection fraction (HFpEF) is characterized by diastolic dysfunction and often occurring in obese individuals. Previous research has demonstrated that the modification of lipid metabolism can prevent the onset of diastolic dysfunction. In our project we have investigated how lipid transport influences the onset of diastolic dysfunction utilizing heart- and adipose tissue-specific knockdowns of the fatty acid (FA) transport protein 1 (FatP1) in Drosophila melanogaster. Methods We generated Drosophila with heart-specific (+/+; Hand4.2-GAL4/UAS-FatP1; tdtK/+) (cFatP1-KD) and adipose tissue-specific (+/+; ppl-GAL4/UAS-FatP1; tdtK/+) (atFat-P1-KD) FatP1 knockdowns using the UAS/GAL4 system. The flies' cardiomyocytes endogenously express tdTomato, facilitating fluorescence-based live imaging of the heart by high-resolution video fluorescence microscopy, as previously described. Cardiac morphology and cardiac lipid accumulation was monitored by confocal microscopy. Additionally, mitochondrial function was evaluated using the glycolytic Seahorse assay of whole hearts. Results Blocking FA-uptake into adipose tissue in atFatP1-KD flies resulted in a highly significant reduction in relaxation velocity (p=0.0009, WT vs. atFatP1-KD), indicative of diastolic dysfunction in flies, while contraction velocity and fractional shortening (systolic function) remained unchanged. Diastolic dysfunction was associated with a significant increase of cardiac lipid droplet (LD) quantity and size in flies lacking FatP1 in adipose tissue (p=0.0275 and p<0.0001, respectively, WT vs. atFatP1-KD). Cardiac mitochondrial function was significantly impaired in atFatP1-KD flies compared to WT flies. Reducing cardiac FA uptake in heart-specific FatP1 KD flies led to a decrease in end-diastolic diameter and a significant reduction in relaxation and contraction velocity (p<0.0001 and p=0.0001, respectively, WT vs. cFatP1-KD), suggesting impairment in both diastolic and systolic function. Interestingly, the number of cardiac LDs increased in cFATP1-KD, however their size decreased significantly resulting in an overall unchanged lipid content compared to WT flies (p=0.0475 and p=0.0367, respectively, WT vs. atFatP1-KD). Mitochondrial function showed no significant alterations. Conclusion This study demonstrates that reducing FA-uptake in adipose or cardiac tissue results in cardiac dysfunction in Drosophila melanogaster. Reduction of adipose tissue FA-uptake results exclusively in diastolic dysfunction likely mediated by cardiac lipid overload and subsequent mitochondrial dysfunction. In contrast, blockade of Fatp1-mediated cardiac FA-uptake induces diastolic/ systolic dysfunction which was unrelated to alterations in cardiac lipid content and mitochondrial dysfunction suggesting alternative mechanisms. These study identifies FatP1-mediated FA-uptake in adipose tissue as a potential therapeutic target for the treatment of diastolic dysfunction.

Lipid droplet-associated proteins in alcohol-associated fatty liver disease: A proteomic approach.

The earliest manifestation of alcohol-associated liver disease (ALD) is steatosis characterized by deposition of fat in specialized organelles called lipid droplets (LDs). While alcohol administration causes a rise in LD numbers in the hepatocytes, little is known regarding their characteristics that allow their accumulation and size to increase. The aim of the present study is to gain insights into underlying pathophysiological mechanisms by investigating the ethanol-induced changes in hepatic LD proteome as a function of LD size. Adult male Wistar rats (180-200 g BW) were fed with ethanol liquid diet for 6 weeks. At sacrifice, large-, medium-, and small-sized hepatic LD subpopulations (LD1, LD2, and LD3, respectively) were isolated and subjected to morphological and proteomic analyses. Morphological analysis of LD1-LD3 fractions of ethanol-fed rats clearly demonstrated that LD1 contained larger LDs compared with LD2 and LD3 fractions. Our preliminary results from principal component analysis showed that the proteome of different-sized hepatic LD fractions was distinctly different. Proteomic data analysis identified over 2000 proteins in each LD fraction with significant alterations in protein abundance among the three LD fractions. Among the altered proteins, several were related to fat metabolism, including synthesis, incorporation of fatty acid, and lipolysis. Ingenuity pathway analysis revealed increased fatty acid synthesis, fatty acid incorporation, LD fusion, and reduced lipolysis in LD1 compared to LD3. Overall, the proteomic findings indicate that the increased level of protein that facilitates fusion of LDs combined with an increased association of negative regulators of lipolysis dictates the generation of large-sized LDs during the development of alcohol-associated hepatic steatosis. Several significantly altered proteins were identified in different-sized LDs isolated from livers of ethanol-fed rats. Ethanol-induced increases in specific proteins that hinder LD lipid metabolism led to the accumulation and persistence of large-sized LDs in the liver.

THIN AND ULTRATHIN STRUCTURE OF ENVELOPES OF STEPHANOSTOMUM BACCATUM (TREMATODA: ACANTHOCOLPIDAE) METACERCARIAE IN YELLOWFIN SOLE, LIMANDA ASPERA.

The structure of the envelopes (capsule and cyst) surrounding metacercariae of Stephanostomum baccatum (Nicoll, 1907) in the second intermediate host, the yellowfin sole Limanda aspera (Pallas 1814), is examined with the methods of light and transmission electron microscopy. The cyst, presumably formed by secretions of the metacercarial tegument, consists of 2 layers: the outer, very thin layer of an electron-dense, finely granular substance and the inner layer composed of loose material of a moderate electron density that includes dense bodies varying in size, shape, and localization. The capsule, formed by the host's cells, is also organized into 2 distinct layers. The inner layer of the capsule is loose, consisting of evenly spaced debris of degenerated cells and lipid droplets with inclusions of intact macrophages between them. The outer layer of the capsule consists of parallel rows of cells arranged around the parasite, with fibroblasts and macrophages being dominant types and granulocytes and lymphocytes found in smaller numbers. Aggregations of collagen fibers are located in narrow spaces between the cells. The number of lipid droplets in the outer layer is significantly smaller than in the inner layer. The capsules formed around the examined trematodes have several structural features that distinguish them from those of S. baccatum and Stephanostomum sp. metacercariae recovered from other fishes of the family Pleuronectidae. The major morphological features of such capsules are the lack of epithelioid or giant multinucleated cells and the presence of numerous lipid droplets. Investigating the structural details of the envelopes surrounding metacercariae in trematodes, as well as other helminths, contributes to our scientific understanding of parasite biology, which can, in turn, have broader implications for understanding host-parasite interactions and evolutionary biology.

Optimised methods to image hepatic lipid droplets in zebrafish larvae.

The optical transparency of zebrafish larvae enables visualization of subcellular structures in intact organs, and these vertebrates are widely used to study lipid biology and liver disease. Lipid droplet (LD) presence is a prevalent feature of healthy cells but under conditions such as nutrient excess, toxicant exposure or metabolic imbalance, LD accumulation in hepatocytes can be a harbinger of more severe forms of liver disease. We undertook a comprehensive analysis of approaches useful to investigate LD distribution and dynamics in physiological and pathological conditions in the liver of zebrafish larvae. This comparative analysis of the lipid dyes oil red O (ORO), Nile Red (NR), LipidTox and LipidSpot as well as transgenic LD reporters that rely on EGFP fusions of the LD decorating protein perilipin 2 (PLIN2) demonstrate the strengths and limitations of each approach. These protocols are amenable to detection methods ranging from low resolution stereomicroscopy to confocal imaging, which enables measurements of hepatic LD size, number and dynamics at cellular resolution in live and fixed animals. This resource will benefit investigators studying LD biology in zebrafish disease models.

The mitigating role of lysophospholipids in hepatic lipid metabolism and intestinal immunity in juvenile black seabream (Acanthopagrus schlegelii) fed a high-fat diet

An 8-week feeding experiment investigated the effects of lysophospholipids (LP) on growth performance, hepatic lipid metabolism, intestinal immunity and antioxidation in juvenile black seabream (Acanthopagrus schlegelii) (initial weight 4.60 ± 0.01 g) on a high-fat diet. Five experimental diets were established: normal fat diet (13 %, CON), high-fat diet (18 %, HFD) and HFD with different levels of LP (0.05 %, 0.1 %, and 0.2 %). The results indicated that dietary LP had no impact on the specific growth rate and survival rate of juvenile black seabream (P > 0.05), while 0.2 %LP supplementation reduced the intraperitoneal fat ratio (IPF) (P < 0.05). Dietary 0.1 % and 0.2 %LP supplementation reduced the total lipid content and the size and number of lipid droplets in the liver (P < 0.05). The diets supplemented with LP reduced the contents of TG and LDL-C in the serum (P < 0.05), without affecting T-CHO and HDL-C (P > 0.05). The expression of lipid transport genes including apoa, apob, fatp1, and fatp4, were markedly up-regulated with increased dietary LP supplementation (P < 0.05). Moreover, dietary 0.2 %LP supplementation notably increased mRNA expression levels of scarb1, ffar3, acsl5 and glp-1 in the intestine (P < 0.05). Dietary LP notably down-regulated the mRNA expression of genes related to the lipogenesis pathway including fas, aco and srebp-1c, while up-regulating mRNA expression of lipogenesis-related genes including cpt1α, lpl, and pparα (P < 0.05). Additionally, dietary 0.2 %LP supplementation notably increased total antioxidant capacity in the intestine and up-regulated expression levels of intestinal antioxidant genes, including mn sod, cu-zn sod, gpx, and cat (P < 0.05), fish fed diets with 0.2 %LP down-regulation of pro-inflammatory genes, including tnfα and nf-κb, and up-regulation of anti-inflammatory factors, tgfβ-1, il-10 and tight-junction protein genes including (oclna, cldni, cldn3, and tjp1b) in the intestine (P < 0.05). In conclusion, dietary LP improved intestinal fatty acid transport and liver lipolysis, alleviating intestinal oxidative damage and inflammatory reactions caused by HFD in black seabream.

Effect of the polyphenol flavonoids fisetin and quercetin on the adipogenic differentiation of human mesenchymal stromal cells.

Fisetin and quercetin, polyphenol flavonoids, have been shown to have a wide range of beneficial pharmacological effects including anti-inflammatory, anti-oxidative, and anti-cancer. Our previous work shows that fisetin also affects the specification of the adipogenic-osteogenic lineage of human mesenchymal stem cells (hMSCs) by modulating the Hippo-YAP signaling pathway. Although quercetin has a structure similar to that of fisetin, its effects on the functional properties of hMSCs have not yet been investigated. The objective of this study is to determine the effects of quercetin on the various properties of hMSCs, including proliferation, migration, and differentiation capacity toward adipogenic and osteogenic lineages. The results show that while fisetin increases hMSC adipogenic differentiation, quercetin inhibited adipogenic differentiation of hMSCs. The inhibition is mediated, at least in part, by the activation of hippo signaling and up-regulation of miR-27b, which inhibits the expression of genes involved in all critical steps of lipid droplet biogenesis, resulting in a decrease in the number of lipid droplets in hMSCs. It is possible that the lack of hydroxylation of the 5 position on the A ring of quercetin could be responsible for its different effect on the adipogenic-osteogenic lineage specification of hMSCs compared to fisetin. Molecular docking and molecular dynamics simulation suggested that fisetin and quercetin possibly bind to serine / threonine protein kinases 4 (STK4/MST1), which is an upstream kinase responsible for LATS phosphorylation. Taken together, our results demonstrate more insight into the mechanism underlying the role of flavonoid fisetin and quercetin in the regulation of adipogenesis.

Female-age-dependent changes in the lipid fingerprint of the mammalian oocytes.

Can oocyte functionality be assessed by observing changes in their intracytoplasmic lipid droplets (LDs) profiles? Lipid profile changes can reliably be detected in human oocytes; lipid changes are linked with maternal age and impaired developmental competence in a mouse model. In all cellular components, lipid damage is the earliest manifestation of oxidative stress (OS), which leads to a cascade of negative consequences for organelles and DNA. Lipid damage is marked by the accumulation of LDs. We hypothesized that impaired oocyte functionality resulting from aging and associated OS could be assessed by changes in LDs profile, hereafter called lipid fingerprint (LF). To investigate if it is possible to detect differences in oocyte LF, we subjected human GV-stage oocytes to spectroscopic examinations. For this, a total of 48 oocytes derived from 26 young healthy women (under 33 years of age) with no history of infertility, enrolled in an oocyte donation program, were analyzed. Furthermore, 30 GV human oocytes from 12 women were analyzed by transmission electron microscopy (TEM). To evaluate the effect of oocytes' lipid profile changes on embryo development, a total of 52 C57BL/6 wild-type mice and 125 Gnpat+/- mice were also used. Human oocytes were assessed by label-free cell imaging via coherent anti-Stokes Raman spectroscopy (CARS). Further confirmation of LF changes was conducted using spontaneous Raman followed by Fourier transform infrared (FTIR) spectroscopies and TEM. Additionally, to evaluate whether LF changes are associated with developmental competence, mouse oocytes and blastocysts were evaluated using TEM and the lipid dyes BODIPY and Nile Red. Mouse embryonic exosomes were evaluated using flow cytometry, FTIR and FT-Raman spectroscopies. Here we demonstrated progressive changes in the LF of oocytes associated with the woman's age consisting of increased LDs size, area, and number. LF variations in oocytes were detectable also within individual donors. This finding makes LF assessment a promising tool to grade oocytes of the same patient, based on their quality. We next demonstrated age-associated changes in oocytes reflected by lipid peroxidation and composition changes; the accumulation of carotenoids; and alterations of structural properties of lipid bilayers. Finally, using a mouse model, we showed that LF changes in oocytes are negatively associated with the secretion of embryonic exosomes prior to implantation. Deficient exosome secretion disrupts communication between the embryo and the uterus and thus may explain recurrent implantation failures in advanced-age patients. Due to differences in lipid content between different species' oocytes, the developmental impact of lipid oxidation and consequent LF changes may differ across mammalian oocytes. Our findings open the possibility to develop an innovative tool for oocyte assessment and highlight likely functional connections between oocyte LDs and embryonic exosome secretion. By recognizing the role of oocyte LF in shaping the embryo's ability to implant, our original work points to future directions of research relevant to developmental biology and reproductive medicine. This research was funded by National Science Centre of Poland, Grants: 2021/41/B/NZ3/03507 and 2019/35/B/NZ4/03547 (to G.E.P.); 2022/44/C/NZ4/00076 (to M.F.H.) and 2019/35/N/NZ3/03213 (to Ł.G.). M.F.H. is a National Agency for Academic Exchange (NAWA) fellow (GA ULM/2019/1/00097/U/00001). K.F. is a Diamond Grant fellow (Ministry of Education and Science GA 0175/DIA/2019/28). The open-access publication of this article was funded by the Priority Research Area BioS under the program "Excellence Initiative - Research University" at the Jagiellonian University in Krakow. The authors declare no competing interest. N/A.

Determination of adipogenesis stages of human umbilical cord-derived mesenchymal stem cells using three-dimensional label-free holotomography

Adipogenesis involves complex changes in gene expression, morphology, and cytoskeletal organization. However, the quantitative analysis of live cell images to identify their stages through morphological markers is limited. Distinct adipogenesis markers on human umbilical cord-derived mesenchymal stem cells (UC-MSCs) were identified through holotomography, a label-free live cell imaging technique. In the MSC-to-preadipocyte transition, the nucleus-to-cytoplasm ratio (0.080 vs. 0.052) and lipid droplet (LD) refractive index variation decreased (0.149 % vs. 0.061 %), whereas the LD number (20 vs. 65) increased. This event was also accompanied by the downregulation and upregulation of THY1 and Preadipocyte Factor-1 (PREF-1), respectively. In the preadipocyte to immature adipocyte shift, cell sphericity (0.20 vs. 0.43) and LD number (65 vs. 200) surged, large LDs (>10 μm3) appeared, and the major axis of the cell was reduced (143.7 μm vs. 83.12 μm). These findings indicate features of preadipocyte and immature adipocyte stages, alongside the downregulation of PREF-1 and upregulation of Peroxisome Proliferator-Activated Receptor gamma (PPARγ). In adipocyte maturation, along with PPARγ and Fatty Acid-Binding Protein 4 upregulation, cell compactness (0.15 vs. 0.29) and sphericity (0.43 vs. 0.59) increased, and larger LDs (>30 μm3) formed, marking immature and mature adipocyte stages. The study highlights the distinct adipogenic morphological biomarkers of adipogenesis stages in UC-MSCs, providing potential applications in biomedical and clinical settings, such as fostering innovative medical strategies for treating metabolic disease.

Distribution of lipid droplets in hippocampal neurons and microglia: impact of diabetes and exercise.

Neuroinflammation, aging, and neurodegenerative disorders are associated with excessive accumulation of neutral lipids in lipid droplets (LDs) in microglia. Type 2 diabetes mellitus (T2DM) may cause neuroinflammation and is a risk factor for neurodegenerative disorders. Here, we show that hippocampal pyramidal neurons contain smaller, more abundant LDs than their neighboring microglia. The density of LDs varied between pyramidal cells in adjacent subregions, with CA3 neurons containing more LDs than CA1 neurons. Within the CA3 region, a gradual increase in the LD content along the pyramidal layer from the hilus toward CA2 was observed. Interestingly, the high neuronal LD content correlated with less ramified microglial morphotypes. Using the db/db model of T2DM, we demonstrated that diabetes increased the number of LDs per microglial cell without affecting the neuronal LD density. High-intensity interval exercise induced smaller changes in the number of LDs in microglia but was not sufficient to counteract the diabetes-induced changes in LD accumulation. The changes observed in response to T2DM may contribute to the cerebral effects of T2DM and provide a mechanistic link between T2DM and neurodegenerative disorders.

NaCl inhibits Geotrichum citri-aurantii growth by inducing lipid droplets accumulation and enhances the biocontrol efficacy of Kloeckera apiculata 34-9

Decays resulting from infections by Geotrichum citri-aurantii cause a significant reduction in citrus postharvest quality and marketable yield. In the present work, 0.8 mol · L-1 NaCl of Generally Recognized as Safe (GRAS) salts were identified to have complete inhibition activity to G. citri-aurantii in vitro and in vivo. An inhibitory mechanism study showed that 0.1 mol · L-1 NaCl changed the expression of six genes (Gci002087, Gci003354, Gci000013, Gci000394, Gci003505 and Gci004433) in target of rapamycin (TOR) pathway, thus inducing a large number of lipid droplets (LDs) accumulation with TEM observations and staining. In vivo, 0.1 mol · L-1 NaCl could raise up the activities of CAT, PAL, PPO and cellulase which hence to strengthen the ability of resistance tolerance of citrus. In addition, NaCl not only accelerated the growth of the biocontrol yeast Kloeckera apiculata strain 34-9, but also increased the expression level of adhesin-encoding genes and biofilm-formation encoding gene (34-9 - 3691). Finally, the storage experiments in 3 months demonstrated that the combination of NaCl and the yeast 34-9 could keep fresh, reduce decay and prolong its shelf-life, thus implying that the combination of biocontrol strain and GRAS salts has been explored as a promising alternative to synthetic fungicides.

Intracellular lipid droplets are exploited by Junín virus in a nucleoprotein-dependent process.

Lipid droplets (LDs) are organelles involved in lipid storage, maintenance of energy homeostasis, protein sequestration, signaling events and inter-organelle interactions. Recently, LDs have been shown to favor the replication of members from different viral families, such as the Flaviviridae and Coronaviridae. In this work, we show that LDs are essential organelles for members of the Arenaviridae family. A virus-driven reduction of LD number was observed in cultures infected with Junín mammarenavirus (JUNV), caused in part by action of the viral nucleoprotein. Notably, we identified a new pool of nucleoprotein and viral RNA that localizes in the vicinity of LDs, suggesting that LDs play a role during the viral replication cycle. Regarding the mechanism behind LD exhaustion, we found evidence that lipophagy is involved in LD degradation with the resulting fatty acids being substrates of fatty acid β-oxidation, which fuels viral multiplication. This work highlights the importance of LDs during the replication cycle of JUNV, contributing to the knowledge of the metabolic changes these mammarenaviruses cause in their hosts.

Long-term arsenic exposure decreases mice body weight and liver lipid droplets

Arsenic (As) is a widespread global pollutant, and there is significant controversy surrounding its complex relationship with obesity, primarily focused on short-term exposure. Recognizing the prolonged nature of dietary arsenic exposure, this study involved feeding mice with arsenic-contained food for 14 months. The results showed that mice exposed to arsenic developed a non-alcoholic fatty liver condition, characterized by a light-yellow hue on the liver surface and various pathological alterations in the liver cells, including enlarged nuclei, cellular necrosis, inflammatory infiltration, dysfunctional mitochondria, and endoplasmic reticulum disorganization. There were also disruptions in biochemistry indices, with a significant increase in total cholesterol (TC) level and a decrease in high-density lipoprotein (HDL) level. However, some contradictory observations occurred, such as a significant decrease in body weight, triglyceride (TG) level, and the numbers of lipid droplets. Several genes related to lipid metabolism were tested, and a model was used to explain these discrepancies. Besides, examinations of the colon revealed compromised intestinal barrier function and signs of inflammation. Fecal 16S rRNA sequencing and pseudo-targeted metabolomics revealed disruptions in internal homeostasis, such as modules, nodes, connections, and lipid-related KEGG pathways. Fecal targeted metabolomics analyses of short-chain fatty acids (SCFAs) and bile acids (BAs) demonstrated a significant upregulation in three primary bile acids (CA, CDCA, TCDCA), four secondary bile acids (TUDCA, DCA, LCA, GUDCA), and total SCFAs level. Oxidative stress and inflammation were also evident. Additionally, based on correlation analysis and mediation analysis, it was assumed that changes in the microbiota (e.g., Dubosiella) can impact the liver metabolites (e.g., TGs) through alterations in fecal metabolites (e.g., LPCs). These findings provide a theoretical reference for the long-term effect of arsenic exposure on liver lipid metabolism.

Effects of pasteurized Akkermansia muciniphila on lipid metabolism disorders induced by high-fat diet in zebrafish (Danio rerio)

Akkermansia muciniphila (Akk) is an important probiotic that can help alleviate metabolic disorders. Recent research indicates that pasteurized Akkermansia muciniphila (P-Akk) is even more effective. To investigate the effect of P-Akk on improving lipid metabolism disorders caused by a high-fat diet (HFD) in fish, zebrafish were fed two HFDs containing 0 (HFD group, as control) and 1 × 109 CFU/g P-Akk (P-Akk group) for 28 days. The addition of P-Akk significantly decreased the number of lipid droplets in the liver and improved the mitochondrial structure in the intestine, while also altering gene expression related to lipid metabolism in HFD-fed zebrafish. Furthermore, intestinal transcriptomic network analysis and results from primary intestinal cells indicated that P-Akk may enhance mitochondrial function by activating the AMPK/PGC1α pathway. Although P-Akk did not significantly alter the composition of the gut microbiota, it did increase the steady-state index of intestinal microbiota. Moreover, P-Akk upregulated the abundance of beneficial probiotics, (Plesiomonas, Cetobacterium, and Bacillus), while downregulating the abundance of pathogens (Aeromonas, Pseudomonas, Acinetobacter, and Streptococcus). Collectively, these findings indicate that P-Akk has the potential to serve as a green and safe feed additive for improving HFD-induced lipid metabolism disorders in fish.

New insights into the functions of ACBD4/5-like proteins using a combined phylogenetic and experimental approach across model organisms

Acyl-CoA binding domain-containing proteins (ACBDs) perform diverse but often uncharacterised functions linked to cellular lipid metabolism. Human ACBD4 and ACBD5 are closely related peroxisomal membrane proteins, involved in tethering of peroxisomes to the ER and capturing fatty acids for peroxisomal β-oxidation. ACBD5 deficiency causes neurological abnormalities including ataxia and white matter disease. Peroxisome-ER contacts depend on an ACBD4/5-FFAT motif, which interacts with ER-resident VAP proteins. As ACBD4/5-like proteins are present in most fungi and all animals, we combined phylogenetic analyses with experimental approaches to improve understanding of their evolution and functions. Notably, all vertebrates exhibit gene sequences for both ACBD4 and ACBD5, while invertebrates and fungi possess only a single ACBD4/5-like protein. Our analyses revealed alterations in domain structure and FFAT sequences, which help understanding functional diversification of ACBD4/5-like proteins. We show that the Drosophila melanogaster ACBD4/5-like protein possesses a functional FFAT motif to tether peroxisomes to the ER via Dm_Vap33. Depletion of Dm_Acbd4/5 caused peroxisome redistribution in wing neurons and reduced life expectancy. In contrast, the ACBD4/5-like protein of the filamentous fungus Ustilago maydis lacks a FFAT motif and does not interact with Um_Vap33. Loss of Um_Acbd4/5 resulted in an accumulation of peroxisomes and early endosomes at the hyphal tip. Moreover, lipid droplet numbers increased, and mitochondrial membrane potential declined, implying altered lipid homeostasis. Our findings reveal differences between tethering and metabolic functions of ACBD4/5-like proteins across evolution, improving our understanding of ACBD4/5 function in health and disease. The need for a unifying nomenclature for ACBD proteins is discussed.

HIV-TAT dysregulates microglial lipid metabolism through SREBP2/miR-124 axis: Implication of lipid droplet accumulation microglia in NeuroHIV

Chronic HIV infection can dysregulate lipid/cholesterol metabolism in the peripheral system, contributing to the higher incidences of diabetes and atherosclerosis in HIV (+) individuals. Recently, accumulating evidence indicate that HIV proteins can also dysregulate lipid/cholesterol metabolism in the brain and such dysregulation could be linked with the pathogenesis of HIV-associated neurological disorders (HAND)/NeuroHIV. To further characterize the association between lipid/cholesterol metabolism and HAND, we employed HIV-inducible transactivator of transcription (iTAT) and control mice to compare their brain lipid profiles. Our results reveal that HIV-iTAT mice possess dysregulated lipid profiles and have increased numbers of lipid droplets (LDs) accumulation microglia (LDAM) in the brains. HIV protein TAT can upregulate LDs formation through enhancing the lipid/cholesterol synthesis in vitro. Mechanistically, HIV-TAT increases the expression of sterol regulatory element-binding protein 2 (SREBP2) through microRNA-124 downregulation. Cholesterol synthesis inhibition can block HIV-TAT-mediated NLRP3 inflammasome activation and microglial activation in vitro as well as mitigate aging-related behavioral impairment and memory deficiency in HIV-iTAT mice. Taken together, our results indicate an inherent role of lipid metabolism and LDAM in the pathogenesis of NeuroHIV (immunometabolism). These findings suggest that LDAM reversal through modulating lipid/cholesterol metabolism could be a novel therapeutic target for ameliorating NeuroHIV symptoms in chronic HIV (+) individuals.

Genome-Wide Association Study of Cuticle and Lipid Droplet Properties of Cucumber (Cucumis sativus L.) Fruit.

The fruit surface is a critical first line of defense against environmental stress. Overlaying the fruit epidermis is the cuticle, comprising a matrix of cutin monomers and waxes that provides protection and mechanical support throughout development. The epidermal layer of the cucumber (Cucumis sativus L.) fruit also contains prominent lipid droplets, which have recently been recognized as dynamic organelles involved in lipid storage and metabolism, stress response, and the accumulation of specialized metabolites. Our objective was to genetically characterize natural variations for traits associated with the cuticle and lipid droplets in cucumber fruit. Phenotypic characterization and genome-wide association studies (GWAS) were performed using a resequenced cucumber core collection accounting for >96% of the allelic diversity present in the U.S. National Plant Germplasm System collection. The collection was grown in the field, and fruit were harvested at 16-20 days post-anthesis, an age when the cuticle thickness and the number and size of lipid droplets have stabilized. Fresh fruit tissue sections were prepared to measure cuticle thickness and lipid droplet size and number. The collection showed extensive variation for the measured traits. GWAS identified several QTLs corresponding with genes previously implicated in cuticle or lipid biosynthesis, including the transcription factor SHINE1/WIN1, as well as suggesting new candidate genes, including a potential lipid-transfer domain containing protein found in association with isolated lipid droplets.

Exploring the effect and mechanism of Hippophae rhamnoides L. triterpenoid acids on improving NAFLD based on network pharmacology and experimental validation in vivo and in vitro

Ethnopharmacological relevanceSea buckthorn (Hippophae rhamnoides L.) is a traditional Chinese medicinal and possesses a rich medical history in terms of treating gastric disorders, sputum and cough and liver injuries in oriental medicinal system. By reason of the complicated chemical constituents, the material basis and potential pharmacological mechanism of sea buckthorn acting on Non-alcoholic fatty liver disease (NAFLD) has not been clearly elucidated. Aim of the studyTo explore the pharmacological efficacy and underlying mechanism of sea buckthorn triterpenoid acid enrichment (STE) in the treatment of NAFLD. Materials and methodsThe approaches of Network pharmacology and experiment validation in vitro and in vivo were applied in this study. Firstly, targets of triterpenoid acid compounds and NAFLD were collected from databases. The crucial targets were screened by the construction of protein-protein interaction (PPI) network. Furthermore, the potential signaling pathways and targets affected by STE was predicted by GO together with KEGG enrichment analysis. Finally, the experiment validation was carried out through high-fat feeding NAFLD mice and lipid accumulation HepG2 cell model. Lipids and liver related biochemical indicators were determined, Oil Red O and H&E staining were employed to observe fat accumulation. In addition, the expression levels of proteins of key target and signal pathway anticipated in network pharmacology were detected to elaborated its action mechanism. ResultsA total of 180 intersecting potential targets for enhancing NAFLD with STE were eventually identified. 6 key targets including AKT1, TNF, IL6, INS, JUN, STAT3 and TP53 were further identified and the AMPK-SREBP1 pathway was enriched. Animal experiment result showed that STE treatment could significantly reduce the levels of TG, TC, LDL-C, ALT and AST, increase the levels of HDL-C in serum, and improve lipid accumulation of epididymal fat and liver. The results of the lipid accumulation cell model indicated that STE and key compound oleanolic acid could diminish intracellular lipid levels of TG, TC, LDL-C and number of lipid droplets. Western blot results showed that the above beneficial effects could be achieved by regulating the expression of p-AMPK/AMPK, SREBP1, FAS, ACC, SCD protein. ConclusionThis study confirmed the effect of STE on improving NAFLD and the potential action mechanism was involved in the regulation of the AMPK-SREBP1 pathway.