Structured triacylglycerol containing behenic and oleic acids suppresses triacylglycerol absorption and prevents obesity in rats

<p>Abstract</p> <p>Background</p> <p>Dietary 1(3)-behenoyl-2,3(1)-dioleoyl-<it>rac</it>-glycerol (BOO) has been reported to inhibit pancreatic lipase activity <it>in vitro </it>and suppress postprandial hypertriacylglycerolemia in humans. In the present study, the anti-obesity activities of BOO and its inhibitory effects on lymphatic triacylglycerol (TAG) absorption were investigated in rats.</p> <p>Methods</p> <p>In Experiment 1, rats were fed either BOO or soybean oil (SO) diet for 6 weeks. In the BOO diet, 20% of SO was replaced with an experimental oil rich in BOO. In Experiments 2 and 3, rats cannulated in the thoracic duct were administered an emulsions containing trioleoylglycerol (OOO) or an oil mixture (OOO:BOO, 9:1). Tri[1-¹⁴C]oleoylglycerol (¹⁴C-OOO) was added to the emulsions administered in Experiment 3.</p> <p>Results</p> <p>No observable differences were detected in food intake or body weight gain between the BOO and SO groups in Experiment 1. Plasma and liver TAG concentrations and visceral fat weights were significantly lower in the BOO group than in the SO group. The apparent absorption rate of fat was significantly lower in the BOO group than in the SO group. In Experiment 2, the lymphatic recovery of oleic and behenic acids was significantly lower at 5 and 6 h after BOO administration than after OOO administration. In Experiment 3, the lymphatic recovery of ¹⁴C-OOO was significantly lower at 5 and 6 h after BOO administration than after OOO administration.</p> <p>Conclusions</p> <p>These results suggest that BOO prevents deposition of visceral fat and hepatic TAG by lowering and delaying intestinal absorption of TAG.</p

Cell-Type Specific Roles for PTEN in Establishing a Functional Retinal Architecture

BACKGROUND: The retina has a unique three-dimensional architecture, the precise organization of which allows for complete sampling of the visual field. Along the radial or apicobasal axis, retinal neurons and their dendritic and axonal arbors are segregated into layers, while perpendicular to this axis, in the tangential plane, four of the six neuronal types form patterned cellular arrays, or mosaics. Currently, the molecular cues that control retinal cell positioning are not well-understood, especially those that operate in the tangential plane. Here we investigated the role of the PTEN phosphatase in establishing a functional retinal architecture. METHODOLOGY/PRINCIPAL FINDINGS: In the developing retina, PTEN was localized preferentially to ganglion, amacrine and horizontal cells, whose somata are distributed in mosaic patterns in the tangential plane. Generation of a retina-specific Pten knock-out resulted in retinal ganglion, amacrine and horizontal cell hypertrophy, and expansion of the inner plexiform layer. The spacing of Pten mutant mosaic populations was also aberrant, as were the arborization and fasciculation patterns of their processes, displaying cell type-specific defects in the radial and tangential dimensions. Irregular oscillatory potentials were also observed in Pten mutant electroretinograms, indicative of asynchronous amacrine cell firing. Furthermore, while Pten mutant RGC axons targeted appropriate brain regions, optokinetic spatial acuity was reduced in Pten mutant animals. Finally, while some features of the Pten mutant retina appeared similar to those reported in Dscam-mutant mice, PTEN expression and activity were normal in the absence of Dscam. CONCLUSIONS/SIGNIFICANCE: We conclude that Pten regulates somal positioning and neurite arborization patterns of a subset of retinal cells that form mosaics, likely functioning independently of Dscam, at least during the embryonic period. Our findings thus reveal an unexpected level of cellular specificity for the multi-purpose phosphatase, and identify Pten as an integral component of a novel cell positioning pathway in the retina

Optimization of prediction methods for risk assessment of pathogenic germline variants in the Japanese population

Predicting pathogenic germline variants (PGVs) in breast cancer patients is important for selecting optimal therapeutics and implementing risk reduction strategies. However, PGV risk factors and the performance of prediction methods in the Japanese population remain unclear. We investigated clinicopathological risk factors using the Tyrer-Cuzick (TC) breast cancer risk evaluation tool to predict BRCA PGVs in unselected Japanese breast cancer patients (n = 1, 995). Eleven breast cancer susceptibility genes were analyzed using target-capture sequencing in a previous study; the PGV prevalence in BRCA1, BRCA2, and PALB2 was 0.75%, 3.1%, and 0.45%, respectively. Significant associations were found between the presence of BRCA PGVs and early disease onset, number of familial cancer cases (up to third-degree relatives), triple-negative breast cancer patients under the age of 60, and ovarian cancer history (all P < .0001). In total, 816 patients (40.9%) satisfied the National Comprehensive Cancer Network (NCCN) guidelines for recommending multigene testing. The sensitivity and specificity of the NCCN criteria for discriminating PGV carriers from noncarriers were 71.3% and 60.7%, respectively. The TC model showed good discrimination for predicting BRCA PGVs (area under the curve, 0.75; 95% confidence interval, 0.69-0.81). Furthermore, use of the TC model with an optimized cutoff of TC score ≥0.16% in addition to the NCCN guidelines improved the predictive efficiency for high-risk groups (sensitivity, 77.2%; specificity, 54.8%; about 11 genes). Given the influence of ethnic differences on prediction, we consider that further studies are warranted to elucidate the role of environmental and genetic factors for realizing precise prediction

Decreased circulating branched-chain amino acids are associated with development of Alzheimer’s disease in elderly individuals with mild cognitive impairment

BackgroundNutritional epidemiology has shown that inadequate dietary protein intake is associated with poor brain function in the elderly population. The plasma free amino acid (PFAA) profile reflects nutritional status and may have the potential to predict future changes in cognitive function. Here, we report the results of a 2-year interim analysis of a 3-year longitudinal study following mild cognitive impairment (MCI) participants.MethodIn a multicenter prospective cohort design, MCI participants were recruited, and fasting plasma samples were collected. Based on clinical assessment of cognitive function up to 2 years after blood collection, MCI participants were divided into two groups: remained with MCI or reverted to cognitively normal (“MCI-stable,” N = 87) and converted to Alzheimer’s disease (AD) (“AD-convert,” N = 68). The baseline PFAA profile was compared between the two groups. Stratified analysis based on apolipoprotein E ε4 (APOE ε4) allele possession was also conducted.ResultsPlasma concentrations of all nine essential amino acids (EAAs) were lower in the AD-convert group. Among EAAs, three branched-chain amino acids (BCAAs), valine, leucine and isoleucine, and histidine (His) exhibited significant differences even in the logistic regression model adjusted for potential confounding factors such as age, sex, body mass index (BMI), and APOE ε4 possession (p &lt; 0.05). In the stratified analysis, differences in plasma concentrations of these four EAAs were more pronounced in the APOE ε4-negative group.ConclusionThe PFAA profile, especially decreases in BCAAs and His, is associated with development of AD in MCI participants, and the difference was larger in the APOE ε4-negative population, suggesting that the PFAA profile is an independent risk indicator for AD development. Measuring the PFAA profile may have importance in assessing the risk of AD conversion in the MCI population, possibly reflecting nutritional status.Clinical trial registration[https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000025322], identifier [UMIN000021965]

Elucidating the Role of Pten in Retinal Development and Pattern Formation

The retina is a neural tissue that is a part of the central nervous system that resides at the back of the eye. It serves as the first sensory processing center of the visual environment. All of the cell types in the retina have been well-characterized, and their physiological functions are generally well described. As a member of a developmental biology laboratory, I have been interested in understanding the factors that dictate the events that regulate the precisely orchestrated development of the retina, such as the proliferation of neural progenitors, differentiation of neuronal cell types, migration of neuronal cells to their designated destinations, and the formation of synaptic connections. When this project was undertaken, very little was understood about the role of the Pten (phosphatase and tensin homologue) phosphatase and PI3K (phosphatidylinositol 3-kinase) signaling pathway in the retina. While PI3K signaling was known to be responsible for proliferation, differentiation, cell death, migration, neurite outgrowth, and synapse formation in different regions of the developing CNS, its role in the retina was understudied. In this thesis, I describe experiments in which I deleted Pten gene in the mouse retina with a conditional knockout (cKO) approach to elucidate its role in retinal development. During early retinal development, I found that Pten is required to regulate the differentiation of retinal amacrine cells and rod photoreceptors. I focused on amacrine cells, and found that Pten regulates amacrine cell number by modulating three different signaling pathways, Akt, TgfβII, and Erk (Chapter 3). Furthermore, I found that the deletion of Pten in the peripheral and not central retina created an animal model of Pten hamartoma tumor syndrome (PHTS), with the central ‘wild-type’-like retinal tissue forming a hamartoma-like lesion (Chapter 4). Finally, I described a role for Pten at later stages of the retinal development in regulating cellular patterning (Chapter 5). Specifically, I observed several examples of mispatterning in Pten cKO retinas, including an expansion of the inner plexiform layer, and the disrupted organization of amacrine cells in both the radial and tangential planes. I also investigated genetic relationships between Pten and the cell adhesion molecule Dscam in guiding cellular positioning, as the deletion of Dscam largely phenocopies the Pten cKO in the retina, and I found for the most part that they act in separate pathways. In summary, I have significantly expanded our knowledge of Pten function in the developing retina during my PhD studies

Flow cytometric analysis of phosphatidylcholine metabolism using organelle-selective click labeling

Summary: Here, we present a protocol to analyze phosphatidylcholine (PC) metabolism in mammalian cells using organelle-selective click labeling coupled with flow cytometry (O-ClickFC). We describe steps for the metabolic incorporation of azide-choline into PC. We then detail fluorescent labeling of the azide-modified PC with organelle-targeting clickable dyes in the ER-Golgi, plasma membrane, and mitochondria, and by flow cytometry. This protocol is optimized for flow cytometric quantification of the labeled PC at the organelle level within single live cells.For complete details on the use and execution of this protocol, please refer to Tsuchiya et al. (2023).1 : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics

Soy Phospholipids Exert a Renoprotective Effect by Inhibiting the Nuclear Factor Kappa B Pathway in Macrophages

Complications associated with chronic kidney disease (CKD), which involves kidney inflammation, are a major health problem. Soy protein isolate (SPI) reportedly inhibits CKD exacerbation; however, its detailed action mechanism remains obscure. Therefore, the role of the polar lipid component of SPI in suppressing inflammation was investigated. Zucker fatty rats were divided into three groups and fed a diet containing casein, SPI, or casein + SPI ethanol extract (SPIEE) for 16 weeks. The isoflavones and phospholipids of SPIEE were evaluated for their anti-inflammatory effects. Rats in the SPI and casein + SPIEE groups showed reduced levels of the urinary N-acetyl-&beta;-d-glucosaminidase and renal IL-1&beta; mRNA (an inflammatory marker) compared with those in the casein group. In proximal tubular cells, genistein significantly inhibited monocyte chemoattractant protein-1 (MCP-1) expression induced by an IL-1&beta; stimulus. In macrophages, soybean phospholipids suppressed lipopolysaccharide-induced IL-1&beta; gene expression by inhibiting the phosphorylation of inhibitor &kappa;B and p65. Phosphatidylinositol (PI) was found to be essential for inhibition of IL-1&beta; expression. SPIEE inhibited the exacerbation of kidney disease. Genistein and soybean phospholipids, especially soybean-specific phospholipids containing PI, effectively inhibited the inflammatory spiral in vitro. Hence, daily soybean intake may be effective for inhibiting chronic inflammation and slowing kidney disease progression

Dual microglia effects on blood brain barrier permeability induced by systemic inflammation

Microglia survey brain parenchyma, responding to injury and infections. Microglia also respond to systemic disease, but the role of blood-brain barrier (BBB) integrity in this process remains unclear. Using simultaneous in vivo imaging, we demonstrated that systemic inflammation induces CCR5-dependent migration of brain resident microglia to the cerebral vasculature. Vessel-associated microglia initially maintain BBB integrity via expression of the tight-junction protein Claudin-5 and make physical contact with endothelial cells. During sustained inflammation, microglia phagocytose astrocytic end-feet and impair BBB function. Our results show microglia play a dual role in maintaining BBB integrity with implications for elucidating how systemic immune-activation impacts neural functions