Exogenous Lipids Research Articles

Effects of exogenous lipids and cold acclimation on lycopene production and fatty acid composition in Blakeslea trispora

Exogenous lipids serving as stimulators to improve lycopene production in Blakeslea trispora have been widely reported. However, the selection basis of exogenous lipids and their effects on intracellular lipids are not very clear. In this study, five plant oils with different fatty acid compositions were selected to investigate their effects on lycopene production, fatty acid composition and the desaturation degree of intracellular lipids. Among the oils, soybean oil, with a fatty acid composition similar to that of mycelium, exhibited the best stimulating effect on lycopene formation (improvement of 82.1%). The plant oils enhanced the total content of intracellular lipids and the desaturation degree of reserve lipids due to the alteration of fatty acid composition, especially in neutral lipids. Lycopene production was increased with the improved desaturation degree of intracellular lipids, which may be attributed to the enhancement of storage capacity for lycopene in storage lipid, thus reducing the feedback regulation of free lycopene. In addition, the increase of the desaturation degree of reserve lipids through temperature-changing fermentation also enhanced lycopene production. The present study could serve as a basis for a better understanding of the relationship between the fatty acid composition of reserve lipids and lycopene production.

Replacing plasma membrane outer leaflet lipids with exogenous lipid without damaging membrane integrity.

We recently introduced a MαCD-based method to efficiently replace virtually the entire population of plasma membrane outer leaflet phospholipids and sphingolipids of cultured mammalian cells with exogenous lipids (Li et al, (2016) Proc. Natl. Acad. Sci USA 113:14025-14030). Here, we show if the lipid-to- MαCD ratio is too high or low, cells can round up and develop membrane leakiness. We found that this cell damage can be reversed/prevented if cells are allowed to recover from the exchange step by incubation in complete growth medium. After exchange and transfer to complete growth medium cell growth was similar to that of untreated cells. In some cases, cell damage was also prevented by carrying out exchange at close to room temperature (rather than at 37°C). Exchange with lipids that do (sphingomyelin) or do not (unsaturated phosphatidylcholine) support a high level of membrane order in lipid vesicles had the analogous effect on plasma membrane order, confirming exogenous lipid localization in the plasma membrane. Importantly, changes in lipid composition and plasma membrane properties after exchange and recovery persisted for several hours. Thus, it should be possible to use lipid exchange to investigate the effect of plasma membrane lipid composition upon several aspects of membrane structure and function.

A CHALLENGING CASE OF DYSPNEA: ACUTE EXOGENOUS LIPID PNEUMONIA

SESSION TITLE: Wednesday Fellows Case Report Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: 10/23/2019 09:45 AM - 10:45 AM INTRODUCTION: Dyspnea is a common symptom that generally occurs during exertion and is considered pathological when it occurs at rest. Approximately, 90% of dyspnea is caused by pulmonary diseases making it immensely important that dyspnea be thoroughly evaluated as it can be fatal. And even after thorough evaluation, a clear answer for the etiology of patient’s dyspnea is not quite apparent. We report one such challenging case that after a meticulous collaboration from radiologist, pathologist and pulmonologist, and detailed history taking followed by a detailed work-up to rule out more common fatal causes of shortness of breath patient’s etiology of dyspnea was revealed to be acute exogenous lipid pneumonia (ELP) caused by lipid-based vapor rub (LBVR). CASE PRESENTATION: A 67 year old Japanese male with past medical history of hypertension presented to the hospital with worsening non-productive cough and dyspnea at rest for the past two weeks. He has never had such symptoms in the past. He had also started to self-medicate with a LBVR over the past 2 weeks with minimal relief. He denied smoking tobacco and using recreational drugs. He worked in maintaining air conditioners and heat furnaces for the past 40 years. He did not have birds at home. He denied any sick contacts. He has been up-to-date on his vaccinations. During the hospital stay, he was started on community acquired pneumonia (CAP) treatment and was also diuresed daily after chest x-ray revealed non-specific interstitial and alveolar prominence in both lung bases. Despite CAP and heart failure treatment for 3 days, patient continued to require supplemental oxygen (FiO2 of 40%) to maintain oxygen saturation (SpO2) of 92%. He then underwent computed tomography (CT) of chest which showed multi-focal patchy and confluent ground-glass airspace opacities with interstitial thickening in the lower lobes. Due to these findings on CT and no improvement in oxygen requirements, a bronchoscopy was performed with transbronchial biopsy which showed alveoli filled with lipid laden macrophages consistent with lipid pneumonia. Inspection of airway during bronchoscopy revealed tracheobronchopathia osteochondroplastica. He was discharged home with supplemental oxygen and was asked to cease using the LBVR. Patient followed up out-patient and he no longer had dyspnea at rest. His SpO2 had improved to 96% on room air. DISCUSSION: Chronic ELP usually occurs when lipid-based products are aspirated, or inhaled over an extended period. Acute ELP from inhaling LBVR has never been reported. LBVR products are commonly used to help with cough and congestion, however, it can lead to acute ELP as reported in this case. CONCLUSIONS: The usage of LBVR is often overlooked when acquiring history. This case uniquely sheds light on the tendency of over the counter LBVR to acutely cause exogenous lipid pneumonia making it very important for clinicians to inquire about LBVR usage. Reference #1: Betancourt, SL; Martinez-Jimenez, S; Rossi, SE; Truong, MT; Carrillo, J; Erasmus, JJ (January 2010). "Lipoid pneumonia: spectrum of clinical and radiologic manifestations.". AJR. American journal of roentgenology. 194 (1): 103–9. Reference #2: Kim JY, Jung JW, Choi JC, Shin JW, Park IW, Choi BW (February 2014). "Recurrent lipoid pneumonia associated with oil pulling". The International Journal of Tuberculosis and Lung Disease. 18 (2): 251–2 Reference #3: Moe Bell, Marvin (2015). "Lipoid pneumonia: An unusual and preventable illness in elderly patients“. Canadian Family Physician. 61 (9): 775–777. DISCLOSURES: No relevant relationships by Jalal Damani, source=Web Response

Pathogenic CD8+ Epidermis-Resident Memory T Cells Displace Dendritic Epidermal T Cells in Allergic Dermatitis

The skin is our interface with the outside world, and consequently it is exposed to a wide range of microbes and allergens. Recent studies have indicated that allergen-specific skin-resident memory T (TRM) cells play a role in allergic contact dermatitis (ACD). However, the composition and dynamics of the epidermal T-cell subsets during ACD are not known. Here we show that exposure of the skin to the experimental contact allergen DNFB results in a displacement of the normally occurring dendritic epidermal T cells (DETC) concomitant with an accumulation of epidermal CD8+CD69+CD103+ TRM cells in mice. By studying knockout mice, we provide evidence that CD8+ T cells are required for the displacement of the DETC and that DETC are not required for recruitment of CD8+ TRM cells to the epidermis following allergen exposure. We demonstrate that the magnitude of the allergic reaction correlates with the number of CD8+ epidermal TRM cells, which again correlates with allergen dose and number of allergen exposures. Finally, in an attempt to elucidate why CD8+ epidermal TRM cells persist in the epidermis, we show that CD8+ epidermal TRM cells have a higher proliferative capability and are bioenergetically more stable, displaying a higher spare respiratory capacity than DETC.

Membrane Structure-Function Insights from Asymmetric Lipid Vesicles.

The lipid bilayer, together with embedded proteins, is the central structure in biomembranes. While artificial lipid bilayers are useful to model natural membranes, they are generally symmetric, with the same membrane lipid composition in each lipid monolayer (leaflet). In contrast, natural membranes are often asymmetric, with different lipids in each leaflet. To prepare asymmetric lipid vesicles, we developed cyclodextrin-catalyzed phospholipid exchange procedures. The basic method is that an excess of vesicles with one set of lipids (the donor vesicles) is mixed with a second set of vesicles (acceptor vesicles) with a different set of lipids. Cyclodextrin is introduced into the external aqueous solution, so that lipids in the outer leaflet of the vesicles bind to it and are shuttled between the vesicles. At equilibrium, the lipids in the outer leaflet of the acceptor vesicles are replaced by those from the donor vesicles. The exchanged acceptor vesicles are then isolated. Asymmetric vesicles are versatile in terms of vesicle sizes and lipid compositions that can be prepared. Measuring asymmetry is often difficult. A variety of assays can be used to measure the extent of asymmetry, but most are specific for one particular membrane lipid type or class, and there are none that can be used in all situations. Studies using asymmetric vesicles have begun to explore how asymmetry influences lipid movement across the bilayer, the formation of ordered lipid domains, coupling between the physical properties in each leaflet, and membrane protein conformation. Lipid domain formation stands out as one of the most important properties in which asymmetry is likely to be crucial. Lipid bilayers can exist in both liquidlike and solid/ordered-like states depending on lipid structure, and in lipid vesicles with a mixture of lipids highly ordered and disordered domains can coexist. However, until very recently, such studies only had been carried out in symmetric artificial membranes. Whether ordered domains (often called lipid rafts) and disordered lipid domains coexist in asymmetric cell membranes remains controversial partly because lipids favoring the formation of an ordered state are largely restricted to the leaflet facing the external environment. Studies using asymmetric vesicles have recently shown that each leaflet can influence the physical behavior of the other, i.e., that the domain forming properties in each leaflet tend to be coupled, with consequences highly dependent upon the details of lipid structure. Future studies investigating the dependence of coupling and properties upon the details of lipid composition should clarify the potential of natural membranes to form lipid domains. In addition, we recently extended the exchange method to living mammalian cells, using exchange to efficiently replace virtually the entire phospholipid and sphingolipid population of the plasma membrane outer leaflet with exogenous lipids without harming cells. This should allow detailed studies of the functional impact of lipid structure, asymmetry, domain organization, and interactions with membrane proteins in living cells.

Putting Stem Cells on a Low-Fat Diet Switches Their Pluripotent State.

Previous work demonstrating the importance of stem cell metabolism in regulating development ignited a debate on how intrinsic versus extrinsic conditions influence metabolic programming of epigenetics. In this issue of Cell Stem Cell, Cornacchia etal. show that exogenous lipids regulate an acetyl-CoA-dependent switch to influence the intrinsic pluripotent state of hPSCs.

Abstract 3610: Cellular fatty acid uptake is enhanced in tamoxifen-resistant breast cancer cells

Abstract The most accepted therapeutic regimen for treating ER-alpha breast cancer is Tamoxifen. Yet over 30% of patients gain resistance. Recently, lipid metabolism has been rising as a new mode of cancer drug resistance. In order for a rapid growth, cancer cells show a strong avidity for lipid which they obtain by de novo lipogenesis or increasing the uptake of exogenous lipids. Lipid metabolism may confer drug resistance, but little is known about its association with endocrine resistance. Thus, we aimed to investigate the association of lipid metabolism in the context of tamoxifen resistance. First, fatty acid translocase and membrane-associated fatty acid binding protein, both of which are responsible for fatty acid uptake, were overexpressed in MCF7/TAMR-8 and T47D/TR-1, TR-2 cell lines. Also the mRNA level of fatty acid activating enzyme, long-chain fatty-acid-coenzyme A, were elevated as well. Next, through Oil-red-O staining and Nile red staining followed by FACS analysis, we examined whether tamoxifen-resistant cells actually increase fatty acid uptake. When supplemented with free fatty acids, tamoxifen-resistant cell lines showed higher efficiency in fatty acid uptake compared to the control cell lines. Subsequently when the amount of triglyceride accumulation was measured, more TG were present in resistant cells at the basal level and after free fatty acid treatment. Taken together, these results suggest lipid uptake by cancer cells may play a role in driving tamoxifen-resistance in breast cancer. Citation Format: Sewon Hwang, Mi-Ock Lee. Cellular fatty acid uptake is enhanced in tamoxifen-resistant breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3610.

Tailoring the lipid composition of nanoparticles modulates their cellular uptake and affects the viability of triple negative breast cancer cells

Lipid nanoparticles are used widely as anticancer drug and gene delivery systems. Internalizing into the target cell is a prerequisite for the proper activity of many nanoparticulate drugs. We show here, that the lipid composition of a nanoparticle affects its ability to internalize into triple-negative breast cancer cells. The lipid headgroup had the greatest effect on enhancing cellular uptake compared to other segments of the molecule. Having a receptor-targeted headgroup induced the greatest increase in cellular uptake, followed by cationic amine headgroups, both being superior to neutral (zwitterion) phosphatidylcholine or to negatively-charged headgroups. The lipid tails also affected the magnitude of cellular uptake. Longer acyl chains facilitated greater liposomal cellular uptake compared to shorter tails, 18:0 > 16:0 > 14:0. When having the same lipid tail length, unsaturated lipids were superior to saturated ones, 18:1 > 18:0. Interestingly, liposomes composed of phospholipids having 14:0 or 12:0-carbon-long-tails, such as DMPC and DLPC, decreased cell viability in a concertation dependent manner, due to a destabilizing effect these lipids had on the cancer cell membrane. Contrarily, liposomes composed of phospholipids having longer carbon tails (16:0 and 18:0), such as DPPC and HSPC, enhanced cancer cell proliferation. This effect is attributed to the integration of the exogenous liposomal lipids into the cancer-cell membrane, supporting the proliferation process. Cholesterol is a common lipid additive in nanoscale formulations, rigidifying the membrane and stabilizing its structure. Liposomes composed of DMPC (14:0) showed increased cellular uptake when enriched with cholesterol, both by endocytosis and by fusion. Contrarily, the effect of cholesterol on HSPC (18:0) liposomal uptake was minimal. Furthermore, the concentration of nanoparticles in solution affected their cellular uptake. The higher the concentration of nanoparticles the greater the absolute number of nanoparticles taken up per cell. However, the efficiency of nanoparticle uptake, i.e. the percent of nanoparticles taken up by cells, decreased as the concentration of nanoparticles increased. This study demonstrates that tuning the lipid composition and concentration of nanoscale drug delivery systems can be leveraged to modulate their cellular uptake.

Low abundance of mitofusin 2 in dairy cows with moderate fatty liver is associated with alterations in hepatic lipid metabolism

High blood concentrations of nonesterified fatty acids (NEFA) and altered lipid metabolism are key characteristics of fatty liver in dairy cows. In nonruminants, the mitochondrial membrane protein mitofusin 2 (MFN2) plays important roles in regulating mitochondrial function and intrahepatic lipid metabolism. Whether MFN2 is associated with hepatic lipid metabolism in dairy cows with moderate fatty liver is unknown. Therefore, to investigate changes in MFN2 expression and lipid metabolic status in dairy cows with moderate fatty liver, blood and liver samples were collected from healthy dairy cows (n = 10) and cows with moderate fatty liver (n = 10). To determine the effects of MFN2 on lipid metabolism in vitro, hepatocytes isolated from healthy calves were used for small interfering RNA-mediated silencing of MFN2 or adenovirus-mediated overexpression of MFN2 for 48 h, or treated with 0, 0.6, 1.2, or 2.4 mM NEFA for 12 h. Milk production and plasma glucose concentrations in dairy cows with moderate fatty liver were lower, but concentrations of NEFA and β-hydroxybutyrate (BHB) were greater in dairy cows with moderate fatty liver. Dairy cows with moderate fatty liver displayed hepatic lipid accumulation and lower abundance of hepatic MFN2, peroxisome proliferator-activated receptor-α (PPARα), and carnitine palmitoyltransferase 1A (CPT1A). However, sterol regulatory element-binding protein 1c (SREBP-1c), acetyl CoA carboxylase 1 (ACACA), fatty acid synthase (FASN), and diacylglycerol acyltransferase 1 (DGAT1) were more abundant in the livers of dairy cows with moderate fatty liver. In vitro, exogenous NEFA treatment upregulated abundance of SREBP-1c, ACACA, FASN, and DGAT1, and downregulated the abundance of PPARα and CPT1A. These changes were associated with greater lipid accumulation in calf hepatocytes, and MFN2 silencing aggravated this effect. In contrast, overexpression of MFN2-ameliorated exogenous NEFA-induced lipid accumulation by downregulating the abundance of SREBP-1c, ACACA, FASN, and DGAT1, and upregulating the abundance of PPARα and CPT1A in calf hepatocytes. Overall, these data suggest that one cause for the negative effect of excessive NEFA on hepatic lipid accumulation is the inhibition of MFN2. As such, these mechanisms partly explain the development of hepatic steatosis in dairy cows.

Lipid Antigen Presentation by CD1b and CD1d in Lysosomal Storage Disease Patients.

The lysosome has a key role in the presentation of lipid antigens by CD1 molecules. While defects in lipid antigen presentation and in invariant Natural Killer T (iNKT) cell response were detected in several mouse models of lysosomal storage diseases (LSD), the impact of lysosomal engorgement in human lipid antigen presentation is poorly characterized. Here, we analyzed the capacity of monocyte-derived dendritic cells (Mo-DCs) from Fabry, Gaucher, Niemann Pick type C and Mucopolysaccharidosis type VI disease patients to present exogenous antigens to lipid-specific T cells. The CD1b- and CD1d-restricted presentation of lipid antigens by Mo-DCs revealed an ability of LSD patients to induce CD1-restricted T cell responses within the control range. Similarly, freshly isolated monocytes from Fabry and Gaucher disease patients had a normal ability to present α-Galactosylceramide (α-GalCer) antigen by CD1d. Gaucher disease patients' monocytes had an increased capacity to present α-Gal-(1-2)-αGalCer, an antigen that needs internalization and processing to become antigenic. In summary, our results show that Fabry, Gaucher, Niemann Pick type C, and Mucopolysaccharidosis type VI disease patients do not present a decreased capacity to present CD1d-restricted lipid antigens. These observations are in contrast to what was observed in mouse models of LSD. The percentage of total iNKT cells in the peripheral blood of these patients is also similar to control individuals. In addition, we show that the presentation of exogenous lipids that directly bind CD1b, the human CD1 isoform with an intracellular trafficking to the lysosome, is normal in these patients.

Lipid Deprivation Induces a Stable, Naive-to-Primed Intermediate State of Pluripotency in Human PSCs.

Current challenges in capturing naive human pluripotent stem cells (hPSCs) suggest that the factors regulating human naive versus primed pluripotency remain incompletely defined. Here we demonstrate that the widely used Essential 8minimal medium (E8) captures hPSCs at a naive-to-primed intermediate state of pluripotency expressing several naive-like developmental, bioenergetic, and epigenomic features despite providing primed-state-sustaining growth factor conditions. Transcriptionally, E8 hPSCs are marked by activated lipid biosynthesis and suppressed MAPK/TGF-β gene expression, resulting in endogenous ERK inhibition.These features are dependent on lipid-freeculture conditions and are lost upon lipid exposure, whereas short-term pharmacological ERK inhibition restores naive-to-primed intermediate traits even in the presence of lipids. Finally, we identify de novo lipogenesis as a common transcriptional signature of E8 hPSCs and the pre-implantation human epiblast invivo. These findings implicate exogenous lipid availability in regulating human pluripotency and define E8 hPSCs as a stable, naive-to-primed intermediate (NPI) pluripotent state.

Phosphatidylcholine synthesis through cholinephosphate cytidylyltransferase is dispensable in Leishmania major

Phosphatidylcholine (PC) is a major cell membrane constituent and precursor of important second messengers. In Leishmania parasites, PC synthesis can occur via the choline branch of the Kennedy pathway, the N-methylation of phosphatidylethanolamine (PE), or the remodeling of exogenous phospholipids. To investigate the role of de novo PC synthesis in Leishmania major, we focused on the cholinephosphate cytidylyltransferase (CPCT) which catalyzes the formation of CDP-choline, a key intermediate in the choline branch of the Kennedy pathway. Without CPCT, L. major parasites cannot incorporate choline into PC, yet the CPCT-null mutants contain similar levels of PC and PE as wild type parasites. Loss of CPCT does not affect the growth of parasites in complete medium or their virulence in mice. These results suggest that other mechanisms of PC synthesis can compensate the loss of CPCT. Importantly, CPCT-null parasites exhibited severe growth defects when ethanolamine and exogenous lipids became limited or when they were co-cultured with certain bacteria that are known to be members of sandfly midgut microbiota. These findings suggest that Leishmania employ multiple PC synthesis pathways to utilize a diverse pool of nutrients, which may be crucial for their survival and development in the sandfly.

Removal of Serum Lipids and Lipid-Derived Metabolites to Investigate Breast Cancer Cell Biology.

The use of cultured cells has been instrumental in studying biochemical, molecular, and cellular processes. The composition of serum that cells are maintained in can have a profound impact on important cellular checkpoints. Cell growth and apoptosis are analyzed in an estrogen receptor positive breast cancer cell line in the presence of serum that have been treated to remove steroids or lipids, as well-described in the literature. It is shown that maintaining cells in the presence of charcoal-dextran-treated serum causes reduced growth rate, which can be reversed by the addition of estradiol. Silica-treated-serum also slows down cell growth and induces apoptosis. In order to investigate the role of lipids in these phenotypes, the levels of a wide range of lipids in different sera are investigated. It is shown that silica-treatment significantly depletes phosphatidylcholines and cholesterol. It is also shown that lipogenesis is stimulated when cells are cultured with silica-treated-serum and this is reversed by the addition of exogenous lipids, which also restores growth rate and apoptosis. The results show that cultured cells are sensitive to different serum, most likely due to the differences in levels of structural and signaling metabolites present in their growth environment.

Lipid Uptake Is an Androgen-Enhanced Lipid Supply Pathway Associated with Prostate Cancer Disease Progression and Bone Metastasis

De novo lipogenesis is a well-described androgen receptor (AR)-regulated metabolic pathway that supports prostate cancer tumor growth by providing fuel, membrane material, and steroid hormone precursor. In contrast, our current understanding of lipid supply from uptake of exogenous lipids and its regulation by AR is limited, and exogenous lipids may play a much more significant role in prostate cancer and disease progression than previously thought. By applying advanced automated quantitative fluorescence microscopy, we provide the most comprehensive functional analysis of lipid uptake in cancer cells to date and demonstrate that treatment of AR-positive prostate cancer cell lines with androgens results in significantly increased cellular uptake of fatty acids, cholesterol, and low-density lipoprotein particles. Consistent with a direct, regulatory role of AR in this process, androgen-enhanced lipid uptake can be blocked by the AR-antagonist enzalutamide, but is independent of proliferation and cell-cycle progression. This work for the first time comprehensively delineates the lipid transporter landscape in prostate cancer cell lines and patient samples by analysis of transcriptomics and proteomics data, including the plasma membrane proteome. We show that androgen exposure or deprivation regulates the expression of multiple lipid transporters in prostate cancer cell lines and tumor xenografts and that mRNA and protein expression of lipid transporters is enhanced in bone metastatic disease when compared with primary, localized prostate cancer. Our findings provide a strong rationale to investigate lipid uptake as a therapeutic cotarget in the fight against advanced prostate cancer in combination with inhibitors of lipogenesis to delay disease progression and metastasis. IMPLICATIONS: Prostate cancer exhibits metabolic plasticity in acquiring lipids from uptake and lipogenesis at different disease stages, indicating potential therapeutic benefit by cotargeting lipid supply.

SUN-062 Randomized Controlled Trial for Assessment of the Effects of Anaglipitin, a DPP-4 Inhibitor, on Blood Lipids in Type 2 Diabetic Patients

Background and aims: Dyslipidemia, which is associated with type 2 diabetes, additively increases cardiovascular complications. To date several incretin drugs have been reported to improve lipid metabolism. Anagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor and has been reported to improve the metabolism of lipid, mainly cholesterol, in the previous studies. The objective of the present study is to examine the effects of treatment with anagliptin on plasma apolipoprotein and cholesterol fraction in patients with type 2 diabetes. Materials and methods: This multicenter, open-label, randomized (1:1), parallel group study was designed to evaluate the effects of anagliptin on plasma apolipoprotein and cholesterol fraction. It was conducted in 24 patients with type 2 diabetes at the two participating hospitals for a period of 24 weeks. Patients were randomly assigned to anagliptin group (n=12) or control group (n=12). Patients in the anagliptin group were treated with anagliptin at 200 mg twice daily. Patients in the control group did not receive anagliptin and continued the previous treatment. Markers of lipid metabolism were measured at baseline and after 24 weeks of administration. Results: Treatment with anagliptin for 24 weeks significantly reduced fast apolipoprotein B-48, which is a marker of food-derived exogenous lipid uptake, compared to control group (-1.4±0.6 µg/ml vs. 0.8±0.6 µg/ml. P<0.05). Adiponectin was significantly increased from baseline in the anagliptin group (7.4±3.7 µg/ml to 8.6±3.9 µg/ml. P<0.05), although no significant difference was observed in the control group. Glycated hemoglobin (HbA1c) was significantly decreased from baseline in the anagliptin group (7.1±0.5% to 6.8±0.6%. P<0.05), although no significant difference was observed in the control group. Conclusion: This study showed that anagliptin reduced fast apolipoprotein B-48 levels as well as HbA1c.

Lipid droplets participate in modulating innate immune genes in Ctenopharyngodon idella kidney cells

Lipid droplets (LDs) are increasingly being recognized as important immune modulators in mammals, in additional to their function of lipid ester deposition. However, the role of LDs in fish immunity remains poorly understood. In this study, the function of LDs in the innate immune response of Ctenopharyngodon idella kidney (CIK) cells, which are the equivalent of myeloid cells in vertebrates, was investigated. LD number and TG content significantly increased in the CIK cells following exposure to lipopolysaccharide (LPS), peptidoglycan (PGN), and polyriboinosinic-polyribocytidylic acid (Poly [I: C]) for 24 h, accompanied by increases in the relative expression of several innate immune genes. However, fatty acid compositions of the triglycerides were not changed after treatment with these three pathogenic mimics. LPS, PGN, and Poly (I: C) did not alter the relative expressions of lipogenic (FAS, SCD, and DGAT) and lipid catabolic (PPARα, ATGL, and CPT-1) genes. However, these treatments did increase the mRNA levels of lipid transportation genes (FATP/CD36, ACSL1, and ACSL4), and also decreased the non-esterified fatty acid level in the medium. To further explore the role of LDs in the immune response, CIK cells were incubated with different concentrations (0, 100, 200, 300, 400, 500 μM) of exogenous lipid mix (LM; oleic acid [OA]:linoleic acid [LA]:linolenic acid [LNA] = 2:1:1), and were then transferred to a lipid-free medium and incubated for 24 h. LD size and number increased with the increase in lipid levels, and this was accompanied by increased expression of innate immune genes, including MyD88, IRF3, and IL-1β, which were expressed at their highest levels in 300 μM exogenous lipid mix. Interestingly, after incubating with different fatty acids (LM, OA, LA, LNA, arachidonic acid [ARA], and docosahexaenoic acid [DHA]; 300 μM), ARA and DHA were more potent in inducing LD formation and innate immune gene expression in the CIK cells. Finally, atglistatin, an ATGL inhibitor, effectively attenuated the expression of most genes upregulated by ARA or DHA, suggesting that lipolysis may be involved in the regulation of immune genes at the transcriptional level. Overall, the findings of this study demonstrate that LDs are functional organelles that could act as modulators in the innate immune response of CIK cells. Additionally, long-chain polyunsaturated fatty acid enriched LDs play a unique role in regulating this process.

SLAM-ing the brakes on iNKT cell selection.

Members of the SLAM family of receptors promote the progression of invariant natural killer T cells through the thymic maturation process and facilitate proper host responses to exogenous lipid antigen through the recruitment and activity of SAP–Fyn and SHP-1, respectively.

Periprostatic Adipose Tissue Favors Prostate Cancer Cell Invasion in an Obesity-Dependent Manner: Role of Oxidative Stress.

Prostate gland is surrounded by periprostatic adipose tissue (PPAT), which is increasingly believed to play a paracrine role in prostate cancer progression. Our previous work demonstrates that adipocytes promote homing of prostate cancer cells to PPAT and that this effect is upregulated by obesity. Here, we show that once tumor cells have invaded PPAT (mimicked by an in vitro model of coculture), they establish a bidirectional crosstalk with adipocytes, which promotes tumor cell invasion. Indeed, tumor cells induce adipocyte lipolysis and the free fatty acids (FFA) released are taken up and stored by tumor cells. Incubation with exogenous lipids also stimulates tumor cell invasion, underlining the importance of lipid transfer in prostate cancer aggressiveness. Transferred FFAs (after coculture or exogenous lipid treatment) stimulate the expression of one isoform of the pro-oxidant enzyme NADPH oxidase, NOX5. NOX5 increases intracellular reactive oxygen species (ROS) that, in turn, activate a HIF1/MMP14 pathway, which is responsible for the increased tumor cell invasion. In obesity, tumor-surrounding adipocytes are more prone to activate the depicted signaling pathway and to induce tumor invasion. Finally, the expression of NOX5 and MMP14 is upregulated at the invasive front of human tumors where cancer cells are in close proximity to adipocytes and this process is amplified in obese patients, underlining the clinical relevance of our results. IMPLICATIONS: Our work emphasizes the key role of adjacent PPAT in prostate cancer dissemination and proposes new molecular targets for the treatment of obese patients exhibiting aggressive diseases.

Use of Isotope Tracers to Assess Lipid Absorption in Conscious Lymph Fistula Mice.

This protocol provides a comprehensive reference for the evolution of the lymph fistula model, the mechanism of lipid absorption, the detailed procedure for studying lipid absorption using the lymph fistula model, the interpretation of the results, and consideration of the experimental design. The lymph fistula model is an approach to assess the concentration and rate of a range of molecules transported by the lymph by cannulating lymph duct in animals. In this protocol, mice first undergo surgery with the implantation of cannulae in the duodenum and mesenteric lymph duct and are allowed to recover overnight in Bollman restraining cages housed in a temperature-regulated environment. To study in vivo lipid absorption, a lipid emulsion is prepared with labeled tracers, including [3 H]-triolein and [14 C]-cholesterol. On the day of the experiment, mice are continuously infused with lipid emulsion via the duodenum for 6 hr, and lymph is usually collected hourly. At the end of the study, gastrointestinal segments and their luminal contents are collected separately for determination of the digestion, uptake, and transport of exogenous lipids. © 2019 by John Wiley & Sons, Inc.

Long glucan chains reduce in vitro starch digestibility of freshly cooked and retrograded milled rice

Understanding the structural factors related to the starch digestibility of cooked milled rice grains is important in mitigating the impact of diet-related diseases. In this study, changes in starch structure of rice during in vitro digestion and retrogradation is reported for 8 varieties of indica milled rice with apparent amylose ranges from 3 to 34. Results showed that retrogradation is effective in decreasing starch hydrolysis rate (k), while addition of exogenous lipid had no significant effect. Moreover, reduction in digestibility after retrogradation was more effective in high amylose than low amylose or waxy rice. Structurally, strong negative correlations were found between k and starch fractions rich in long glucan chains such as long-chain amylose (LCAM) or intermediate-chain amylose (ICAM). Conversely, strong positive correlation was seen between k and short-chain amylopectin (SCAP). Decreased hydrolysis of LCAM and low levels of SCAP was observed in retrograded rice. This shows that LCAM becomes less susceptible to digestion which consequently results to increased hydrolysis of SCAP as the preferred substrate in rice.