Language：English   Publishing type：Research paper (scientific journal)  

INTRODUCTION: Intramuscular heterogeneity exists in the shear modulus of the rectus femoris (RF) muscle. However, the underlying heterogeneity mechanisms are not entirely understood. Previous research has reported that detachment of superficial tissues reduces the shear modulus by 50%. The aim of this study was to examine the effects of the skin, deep fascia, and intermuscular connections on the shear modulus of the RF at multiple sites. MATERIALS AND METHODS: Eleven donors were fixed using the Thiel method. Measurements were performed at 0°, 60°, and 120° knee flexion in a neutral hip position. Tissue processing was performed under four conditions: superficial tissue (CONT), skin off (SKIN), deep fascia detachment (FASC), and intermuscular connections detachment (ALL). The shear modulus at the proximal, central, and distal regions were measured using ultrasound shear wave elastography. The study was approved by the Sapporo Medical University Ethical Committee. RESULTS: Three-way ANOVA revealed no significant interaction between treatment, site, and angle (P = 0.156), treatment and angle (P = 0.067), or site and angle (P = 0.441). There was a significant effect of treatment (P < 0.001), site (P = 0.010), and angle (P < 0.001) and interaction between treatment and site (P < 0.001). The proximal shear modulus was greater than the central for CONT. There were no significant differences between the measurement sites for SKIN. The distal shear modulus was greater than the proximal for FASC. The distal shear modulus was also greater than the proximal and central for ALL. CONCLUSIONS: Intramuscular regional differences that influence superficial tissue and intermuscular connections of RF elasticity heterogeneity were observed.

DOI： 10.1007/s40477-022-00769-x

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PURPOSE: This study used ultrasound shear wave elastography (SWE) to evaluate the mechanical properties of hamstring muscles from cadaveric specimens with knee flexion contractures. METHODS: Hamstring muscles for tensile testing were harvested from Thiel soft-embalmed cadavers with and without knee flexion contracture. Muscle specimens were mounted on a testing machine. The initial load detected when a tensile load was applied to the distal end was used as the slack length. The cross-sectional areas of the muscle at slack length were measured at the proximal and distal sites using B-mode ultrasonography. Subsequently, the muscle specimen was elongated from the slack length to 8% strain, with the shear modulus measured using SWE. Young's modulus (stress/strain) was calculated based on the displacement and tensile force obtained from the tensile test. RESULTS: Regression analysis showed a significant positive linear relationship between the Young's and shear moduli for all specimens at all the sites (P < 0.01 and coefficient of determination: 0.95-0.99). The Young's and average shear moduli at the proximal and distal sites were higher in all hamstring muscles with contractures than in those without contractures. CONCLUSIONS: SWE can be used to estimate Young's moduli of hamstring muscles with contractures. Muscle specimens with contractures exhibited higher resistance to elongation, thereby indicating that their mechanical properties differed from those of muscles without contractures.

DOI： 10.7759/cureus.68343

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DOI： 10.1007/s10396-024-01436-w

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The incidence of hamstring muscle strain varies among muscles, suggesting that the mechanical stresses associated with elongation may differ among muscles. However, the passive mechanical properties of whole human muscles have rarely been directly measured and clarified. This study aimed to clarify the stress-strain relationship of the hamstring muscles using a soft-embalmed Thiel cadaver. The long heads of the biceps femoris (BFlh), semimembranosus (SM), and semitendinosus (ST) muscles were dissected from eight cadavers. The proximal and distal hamstring tendons were affixed to the mechanical testing machine. Slack length was defined as the muscle length at the initial loading point detected upon the application of a tensile load. Muscle length was measured using a tape measure, and the anatomical cross-sectional area (ACSA) of the muscle was measured at the proximal and distal sites using B-mode ultrasonography. In the loading protocol, the muscle was elongated from its slack length to a maximum of 8% strain at an average rate of 0.83 L0/s, and the amount of displacement and tensile load were measured for each muscle. Further, the strain (%, displacement/slack muscle length) and stress (kPa, tensile load/ACSA) were calculated to evaluate the mechanical properties. Two-way repeated-measures analysis of variance (ANOVA) was used to compare stress changes with increasing muscle strain. A significant interaction between the muscle and strain factors was observed with respect to stress. Post-hoc tests revealed higher stresses in the BFlh and SM than in ST after 3% strain (P < 0.01). However, no significant differences were observed between the BFlh and SM groups. At 8% strain, the BFlh, SM, and ST exhibited stresses of 63.7 ± 12.1, 53.7 ± 23.2, and 21.0 ± 11.9 kPa, respectively. The results indicate that the stress changes associated with muscle strain differed among muscles. In particular, the stress applied to the three muscles at the same strain was found to be higher in the BFlh and SM. Thus, these findings suggest that increased mechanical stress during elongation may contribute to the frequent occurrence of muscle strain in BFlh and SM.

DOI： 10.1016/j.jmbbm.2024.106473

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Aquaporin 9 (AQP9) is an integral membrane protein that facilitates glycerol transport in hepatocytes and adipocytes. Glycerol is necessary as a substrate for gluconeogenesis in the physiological fasted state, suggesting that inhibiting AQP9 function may be beneficial for treating type 2 diabetes associated with fasting hyperglycemia. The n-3 polyunsaturated fatty acids (PUFAs), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are rich in fish oil and lower the risk of metabolic syndrome; however, the effects of EPA and DHA on AQP9 expression in obese and type 2 diabetes are unclear. The KK mouse is an animal model of obesity and type 2 diabetes because of the polymorphisms on leptin receptor gene, which results in a part of cause for obese and diabetic conditions. In this study, we determined the effect of fish oil-derived n-3 PUFA on AQP9 protein expression in the liver and white adipose tissue (WAT) of KK mice and mouse 3T3-L1 adipocytes. The expression of AQP9 protein in the liver, epididymal WAT, and inguinal WAT were markedly decreased following fish oil administration. We also demonstrated that n-3 PUFAs, such as DHA, and to a lesser extent EPA, downregulated AQP9 protein expression in 3T3-L1 adipocytes. Our results suggest that fish oil-derived n-3 PUFAs may regulate the protein expressions of AQP9 in glycerol metabolism-related organs in KK mice and 3T3-L1 adipocytes.

DOI： 10.1016/j.jnutbio.2023.109514

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It is known that there are abnormalities of tight junction functions, cell migration and mitochondrial metabolism in human endometriosis and endometrial carcinoma. In this study, we investigated the effects of growth factors and their inhibitors on the epithelial permeability barrier, cell migration and mitochondrial metabolism in 2D and 2.5D cultures of human endometrioid endometrial carcinoma Sawano cells. We also investigated the changes of bicellular and tricellular tight junction molecules and ciliogenesis induced by these inhibitors. The growth factors TGF-β and EGF affected the epithelial permeability barrier, cell migration and expression of bicellular and tricellular tight junction molecules in 2D and 2.5D cultures of Sawano cells. EW-7197 (a TGF-β receptor inhibitor), AG1478 (an EGFR inhibitor) and SP600125 (a JNK inhibitor) affected the epithelial permeability barrier, cell migration and mitochondrial metabolism and prevented the changes induced by TGF-β and EGF in 2D and 2.5D cultures. EW-7197 and AG1478 induced ciliogenesis in 2.5D cultures. In conclusion, TGF-β and EGF promoted the malignancy of endometrial cancer via interplay among the epithelial permeability barrier, cell migration and mitochondrial metabolism. EW-7197 and AG1478 may be useful as novel therapeutic treatments options for endometrial cancer.

DOI： 10.1080/21688370.2024.2304443

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The supraglottic airway (SGA) is widely used. I-gel Plus is a next-generation i-gel with some improvements, including facilitation of fiberoptic tracheal intubation (FOI). To compare the performance of i-gel Plus and standard i-gel as conduits for FOI, a Thiel-embalmed cadaveric study was conducted. Twenty-two anesthesiologists were enrolled as operators in Experiment 1. The i-gel Plus and standard i-gel were inserted into one cadaver, and the FOI was performed through each SGA. The primary outcome was time required for FOI. The secondary outcomes were the number of attempts and visual analog scale (VAS) score for difficulty in FOI. Moreover, fiberoptic views of the vocal cords in each SGA were assessed by an attending anesthesiologist using nine cadavers in Experiment 2. The percentage of glottic opening (POGO) score without fiberscope tip upward flexion and upward angle of the fiberscope tip to obtain a 100% POGO score were evaluated as secondary outcomes. The time for FOI through i-gel Plus was significantly shorter than that through standard i-gel (median (IQR), i-gel Plus: 30.3 (25.4-39.0) s, vs standard i-gel: 54.7 (29.6-135.0) s; median of differences, 24.4 s; adjusted 95% confidence interval, 3.0-105.7; adjusted P = 0.040). Although the number of attempts for successful FOI was not significantly different, the VAS score for difficulty in the i-gel Plus group was significantly lower (easier) than that in the standard i-gel group. Moreover, i-gel Plus required a significantly smaller upward angle of the fiberscope tip to obtain a 100% POGO score. FOI can be performed more easily using i-gel Plus than using standard i-gel because of the improved fiberoptic visibility of vocal cords.

DOI： 10.1038/s41598-023-45631-0

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BACKGROUND AND OBJECTIVES: There is still no consensus on the analgesic range and mechanisms of action of modified thoracoabdominal nerve block through perichondrial approach (M-TAPA). This cadaveric study aimed to determine the spread of an injectate following simulated M-TAPA. METHODS: Simulated M-TAPA injections (n=8) were administered on both sides of soft embalmed Thiel cadavers with 25 mL of a saline-soluble dye. Anatomic dissection was performed to document staining (deeply, faintly, or not stained) of the anterior cutaneous branches of the thoracoabdominal nerves and determine the extent of the injectate spread of the dye to the intercostal space in the thoracic cage following a simulated M-TAPA. RESULTS: The median (IQR) dermatome of the stained segmental nerve was T10 (T8-T11) and the median (IQR) number of stained segmental nerves was 3 (4-2). The T9, T10 and T11 segmental nerves were stained in 75%, 100% and 62.5% of simulated M-TAPA, respectively. Conversely, the T8 segmental nerve was stained in only 25% of simulated M-TAPA. No injectate spread of dye to the intercostal space in the thoracic cage was observed in eight simulated injections of M-TAPA. CONCLUSION: Our findings suggest that M-TAPA most likely involves the T9, T10 and T11 segmental nerves and that the local anesthetic may not spread to the intercostal space in the thoracic cage in M-TAPA. Further studies are required to confirm the precise mechanism of action and efficacy of M-TAPA in a large sample of human participants.

DOI： 10.1136/rapm-2022-104275

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PURPOSE: Assessing muscle flexibility and architecture is important for hamstring strain injury (HSI) prevention. We investigated the relationship between shear modulus and passive force in hamstring muscles at different sites and the effect of muscle architecture on the slope of the shear modulus-passive force using shear wave elastography (SWE). METHODS: The biceps femoris long head (BFlh), semitendinosus (ST), and semimembranosus (SM) muscles were dissected from nine Thiel-embalmed cadavers and fixed to a custom-made mechanical testing machine. Calibrated weights (0-1800 g) were applied gradually in 150-g increments. The shear modulus and anatomical cross-sectional area (ACSA) were measured at proximal, central, and distal points using SWE. The muscle mass and length were measured before the loading test. The shear modulus-passive load relationship of each tested muscle region was analyzed by fitting a least-squares regression line. The increase in shear modulus slope per unit load was calculated and compared between the muscles before and after normalization by the muscle mass, length, and ACSA. RESULTS: The shear modulus and passive force for all hamstring muscles in each region showed a statistically significant linear correlation. Furthermore, the increase in shear modulus slope was greater for BFlh and ST than for SM (P < 0.05), but after normalization by the muscle length and ACSA, there were no significant differences among the muscles. CONCLUSION: The local mechanical properties of individual hamstring muscles can be indirectly estimated using SWE, and the slope of increase in shear modulus reflects characteristics of the muscle architecture.

DOI： 10.1007/s10396-023-01317-8

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Authorship：Lead author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

Lipid droplets (LDs) have been observed in the nuclei of hepatocytes; however, their significance in liver disease remains unresolved. Our purpose was to explore the pathophysiological features of intranuclear LDs in liver diseases. We included 80 patients who underwent liver biopsies; the specimens were dissected and fixed for electron microscopy analysis. Depending on the presence of adjacent cytoplasmic invagination of the nuclear membrane, LDs in the nuclei were classified into two types: nucleoplasmic LDs (nLDs) and cytoplasmic LD invagination with nucleoplasmic reticulum (cLDs in NR). nLDs were found in 69% liver samples and cLDs in NR were found in 32%; no correlation was observed between the frequencies of the two LD types. nLDs were frequently found in hepatocytes of patients with nonalcoholic steatohepatitis, whereas cLDs in NR were absent from the livers of such patients. Further, cLDs in NR were often found in hepatocytes of patients with lower plasma cholesterol level. This indicates that nLDs do not directly reflect cytoplasmic lipid accumulation and that formation of cLDs in NR is inversely correlated to the secretion of very low-density lipoproteins. Positive correlations were found between the frequencies of nLDs and endoplasmic reticulum (ER) luminal expansion, suggesting that nLDs are formed in the nucleus upon ER stress. This study unveiled the presence of two distinct nuclear LDs in various liver diseases.

Other Link： https://www.nature.com/articles/s41598-023-33977-4

DOI： 10.1038/s41598-023-33977-4

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/febs.16672

DOI： 10.1111/febs.16672

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Controlling axonal mitochondria is important for maintaining normal function of the neural network. Oxygen-glucose deprivation (OGD), a model used for mimicking ischemia, eventually induces neuronal cell death similar to axonal degeneration. Axonal mitochondria are disrupted during OGD-induced neural degeneration; however, the mechanism underlying mitochondrial dysfunction has not been completely understood. We focused on the dynamics of mitochondria in axons exposed to OGD; we observed that the number of motile mitochondria significantly reduced in 1 h following OGD exposure. In our observation, the decreased length of stationary mitochondria was affected by the following factors: first, the halt of motile mitochondria; second, the fission of longer stationary mitochondria; and third, a transformation from tubular to spherical shape in OGD-exposed axons. Motile mitochondria reduction preceded stationary mitochondria fragmentation in OGD exposure; these conditions induced the decrease of stationary mitochondria in three different ways. Our results suggest that mitochondrial morphological changes precede the axonal degeneration while ischemia-induced neurodegeneration.

DOI： 10.1007/s10571-022-01247-y

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Nuclear lipid droplets (LDs) in hepatocytes are derived from precursors of very-low-density lipoprotein in the ER lumen, but it is not known how cells lacking the lipoprotein secretory function form nuclear LDs. Here, we show that the inner nuclear membrane (INM) of U2OS cells harbors triglyceride synthesis enzymes, including ACSL3, AGPAT2, GPAT3/GPAT4, and DGAT1/DGAT2, and generates nuclear LDs in situ. mTOR inhibition increases nuclear LDs by inducing the nuclear translocation of lipin-1 phosphatidic acid (PA) phosphatase. Seipin, a protein essential for normal cytoplasmic LD formation in the ER, is absent in the INM. Knockdown of seipin increases nuclear LDs and PA in the nucleus, whereas seipin overexpression decreases these. Seipin knockdown also up-regulates lipin-1β expression, and lipin-1 knockdown decreases the effect of seipin knockdown on nuclear LDs without affecting PA redistribution. These results indicate that seipin is not directly involved in nuclear LD formation but instead restrains it by affecting lipin-1 expression and intracellular PA distribution.

DOI： 10.1083/jcb.202005026

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Macroautophagy initiates by formation of isolation membranes, but the source of phospholipids for the membrane biogenesis remains elusive. Here, we show that autophagic membranes incorporate newly synthesized phosphatidylcholine, and that CTP:phosphocholine cytidylyltransferase β3 (CCTβ3), an isoform of the rate-limiting enzyme in the Kennedy pathway, plays an essential role. In starved mouse embryo fibroblasts, CCTβ3 is initially recruited to autophagic membranes, but upon prolonged starvation, it concentrates on lipid droplets that are generated from autophagic degradation products. Omegasomes and isolation membranes emanate from around those lipid droplets. Autophagy in prolonged starvation is suppressed by knockdown of CCTβ3 and is enhanced by its overexpression. This CCTβ3-dependent mechanism is also present in U2OS, an osteosarcoma cell line, and autophagy and cell survival in starvation are decreased by CCTβ3 depletion. The results demonstrate that phosphatidylcholine synthesis through CCTβ3 activation on lipid droplets is crucial for sustaining autophagy and long-term cell survival.

DOI： 10.1038/s41467-020-18153-w

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Publishing type：Research paper (scientific journal)   Publisher：Biophysical Society of Japan  

DOI： 10.2142/biophys.60.267

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Lipid droplets are cytoplasmic microscale organelles involved in energy homeostasis and handling of cellular lipids and proteins. The core structure is mainly composed of two kinds of neutral lipids, triglycerides and cholesteryl esters, which are coated by a phospholipid monolayer and proteins. Despite the liquid crystalline nature of cholesteryl esters, the connection between the lipid composition and physical states is poorly understood. Here, we present a universal intracellular phase diagram of lipid droplets, semiquantitatively consistent with the in vitro phase diagram, and reveal that cholesterol esters cause the liquid-liquid crystal phase transition under near-physiological conditions. We moreover combine in vivo and in vitro studies, together with the theory of confined liquid crystals, to suggest that the radial molecular alignments in the liquid crystallized lipid droplets are caused by an anchoring force at the droplet surface. Our findings on the phase transition of lipid droplets and resulting molecular organization contribute to a better understanding of their biological functions and diseases.

DOI： 10.1073/pnas.1916248116

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Nature  

The original version of this Article contained errors in the Abstract and Introduction, whereby CCTα was incorrectly defined as an abbreviation of CDP-choline diacylglycerol phosphotransferase α, instead of CTP:phosphocholine cytidylyltransferase α. This has now been corrected in both the PDF and HTML versions of the Article.

DOI： 10.1038/s41467-019-08411-x

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The origin and physiological significance of lipid droplets (LDs) in the nucleus is not clear. Here we show that nuclear LDs in hepatocytes are derived from apolipoprotein B (ApoB)-free lumenal LDs, a precursor to very low-density lipoproprotein (VLDL) generated in the ER lumen by microsomal triglyceride transfer protein. ApoB-free lumenal LDs accumulate under ER stress, grow within the lumen of the type I nucleoplasmic reticulum, and turn into nucleoplasmic LDs by disintegration of the surrounding inner nuclear membrane. Oleic acid with or without tunicamycin significantly increases the formation of nucleoplasmic LDs, to which CDP-choline diacylglycerol phosphotransferase α (CCTα) is recruited, resulting in activation of phosphatidylcholine (PC) synthesis. Perilipin-3 competes with CCTα in binding to nucleoplasmic LDs, and thus, knockdown and overexpression of perilipin-3 increases and decreases PC synthesis, respectively. The results indicate that nucleoplasmic LDs in hepatocytes constitute a feedback mechanism to regulate PC synthesis in accordance with ER stress.

DOI： 10.1038/s41467-019-08411-x

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Publishing type：Research paper (scientific journal)   Publisher：SAGE Publications  

The lipid droplet (LD) is a cytoplasmic organelle, but it also exists in the nucleus under some conditions or in some cell types. New studies have revealed that nuclear LDs do not occur by haphazard entry of cytoplasmic LDs. Instead, they are generated by specific mechanisms that are increasingly understood. The inner nuclear membrane (INM) plays a critical role in nuclear LD formation in both mammalian hepatocytes and budding yeast, although in significantly different ways. Hepatocyte nuclear LDs derive from precursors of very low-density lipoprotein lacking apolipoprotein B-100, which form in the endoplasmic reticulum lumen and accumulate in intranuclear extensions of the perinuclear space called type I nucleoplasmic reticulum. In contrast, nuclear LDs in yeast are generated by triglyceride synthesized in the INM. Nuclear LDs in hepatocytes and budding yeast are both instrumental in the regulation of phospholipid synthesis; however, again they function in different ways. As the full functional importance is as yet unknown, the close relationship of nuclear LDs and the INM is an attractive target of research from both physiological and pathological perspectives.

Other Link： http://journals.sagepub.com/doi/full-xml/10.1177/2515256419896965

DOI： 10.1177/2515256419896965

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Because lipid droplets (LDs) and the nucleus are cellular organelles that regulate seemingly very different biochemical processes, very little attention has been focused on their possible interplay. Here, we report a correlation between nuclear morphology and cytoplasmic LD formation in HeLa human cervical cells. When the cells were treated with oleic acid (OA), LDs were formed in the cytoplasm, but not in the nucleoplasm. Interestingly, cells harboring OA-induced cytoplasmic LDs showed deformity of the nucleus, particularly at the nuclear rim. Conversely, when alteration from a single spherical nuclear shape to a multinucleated form was enforced by coadministration of paclitaxel and reversine, a significant amount of LDs was detected in the cytoplasm of the multinucleated cells. These two distinct pharmacological culture conditions not only allow analysis of the previously underappreciated organelle relationship, but also provide insights into the mutual affectability of LD formation and nuclear deformation.

DOI： 10.1016/j.bbrc.2018.08.200

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Society for Biochemistry and Molecular Biology Inc.  

DOI： 10.1194/jlr.M081679

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer New York LLC  

DOI： 10.1007/978-981-10-4567-7_8

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DOI： 10.1267/ahc.17025

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DOI： 10.1083/jcb.201507122

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DOI： 10.1002/hep.26930

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DOI： 10.1016/j.chembiol.2013.08.009

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DOI： 10.1016/j.febslet.2013.09.036

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Mutations affecting the N-glycosylation site in Berardinelli-Seip lipodystrophy (BSCL)-associated gene BSCL2/seipin lead to a dominantly inherited spastic paraplegia termed seipinopathy. While the loss of function of seipin leads to severe congenital lipodystrophy, the effects of seipin N-glycosylation mutations on lipid balance in the nervous system are unknown. In this study, we show that expression of seipin N-glycosylation mutant N88S led to decreased triglyceride (TG) content in astrocytoma and motor neuron cell lines. This was corrected by supplementation with exogenous oleic acid. Upon oleic acid loading, seipin N88S protein was relocated from the endoplasmic reticulum (ER) to the surface of lipid droplets and this was paralleled by alleviation of ER stress induced by the mutant protein. This effect was not limited to seipin N88S, as oleic acid loading also reduced tunicamycin-induced ER stress in motor neuron cells. Furthermore, both seipin N88S and tunicamycin-induced ER stress were decreased by inhibiting lipolysis, suggesting that lipid droplets protected neuronal cells from ER stress. In developing zebrafish larvae, seipin N88S expression led to TG imbalance and reduced spontaneous free swimming. Importantly, supplementation with exogenous oleic acid reduced ER stress in the zebrafish head and increased fish motility. We propose that the decreased TG content contributes to the pathology induced by seipin N88S, and that rescuing TG levels may provide a novel therapeutic strategy in seipinopathy.

DOI： 10.1093/hmg/dds523

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DOI： 10.1016/B978-0-12-408051-5.00012-7

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DOI： 10.1016/j.bbalip.2012.08.004

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DOI： 10.1091/mbc.E11-11-0950

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Lipid droplets (LDs) in non-adipocytes contain triglycerides (TG) and cholesterol esters (CE) in variable ratios. TG-rich LDs are generated when unsaturated fatty acids are administered, but the conditions that induce CE-rich LD formation are less well characterized. In the present study, we found that protein translation inhibitors such as cycloheximide (CHX) induced generation of CE-rich LDs and that TIP47 (perilipin 3) was recruited to the LDs, although the expression of this protein was reduced drastically. Electron microscopy revealed that LDs formed in CHX-treated cells possess a distinct electron-dense rim that is not found in TG-rich LDs, whose formation is induced by oleic acid. CHX treatment caused upregulation of mTORC1, but the CHX-induced increase in CE-rich LDs occurred even when rapamycin or Torin1 was given along with CHX. Moreover, the increase in CE was seen in both wild-type and autophagy-deficient Atg5-null mouse embryonic fibroblasts, indicating that mTORC1 activation and suppression of autophagy are not necessary to induce the observed phenomenon. The results showed that translation inhibitors cause a significant change in the lipid ester composition of LDs by a mechanism independent of mTORC1 signaling and autophagy.

DOI： 10.1371/journal.pone.0042379

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DOI： 10.1097/MOL.0b013e32834d1729

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DOI： 10.1016/j.chemphyslip.2011.03.002

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DOI： 10.1093/jmicro/dfr016

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DOI： 10.1111/j.1600-0854.2010.01142.x

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DOI： 10.1007/s00418-010-0759-x

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DOI： 10.1128/JVI.01063-10

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DOI： 10.1016/j.virol.2010.08.011

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DOI： 10.1007/s00418-010-0678-x

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DOI： 10.1007/s00418-009-0615-z

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DOI： 10.1016/j.bbalip.2008.10.002

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DOI： 10.2353/ajpath.2008.080137

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DOI： 10.1007/s00418-008-0449-0

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Apolipoprotein B-100 (ApoB) is a major component of very-low-density lipoproteins, and is deposited in a region around lipid droplets (LDs) called the ;ApoB-crescent&#039;. The ApoB-crescent is thought to be related to ApoB degradation because it drastically increases when proteasome or autophagy is inhibited. In the present study, we found that ApoB-crescents were significantly reduced when ApoB lipidation was suppressed by either the inhibition or knockdown of the microsomal triglyceride-transfer protein. By contrast, ApoB-crescents increased under conditions that are presumed to cause lipidated ApoB abnormalities in secretory compartments. By electron microscopic analyses, we identified the ApoB-crescent as a thin cholesterol-rich ER cistern fused to an LD, and - topologically - this structure is equivalent to a lipid-ester globule between the two leaflets of the ER membrane. ApoB localized in the thin cisternal lumen, and its binding to LDs was resistant to alkaline treatment. Overexpression of ADRP or TIP47 suppressed the increase in the number of ApoB-crescents, whereas knockdown of these proteins had the opposite effect. From these results, we inferred that the ApoB-crescent is f

DOI： 10.1242/jcs.025452

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In the development of mouse gut, longitudinal smooth muscle cells (LMC) and interstitial cells of Cajal (ICC) originate from common precursor cells expressing c-Kit. Recently, some gastrointestinal stromal tumours, which develop from smooth muscle layers of the gut and have gain-of-function mutations of c-kit, have been reported to have gain-of-function mutations of platelet-derived growth factor (PDGF) receptor alpha gene. These data raise the possibility that PDGF signalling might be involved in the development of LMC. Therefore, we examined the expression pattern of the PDGF signal family of embryonic gut by immunohistochemistry and in situ hybridization, and investigated the role of PDGF signals in the development of smooth muscle layers in mouse gut using a new organ culture system. During embryonic development, the circular muscle layer expressed PDGF-A, enteric neurons expressed PDGF-B and common precursor cells of LMC and ICC expressed both PDGF receptor alpha and beta. The selective PDGF receptor inhibitor AG1295 suppressed the differentiation of LMC in gut explants. We conclude that PDGF signals play critical roles in the differentiation of LMC in mouse embryonic gut.

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DOI： 10.1167/iovs.06-0768

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1523/JNEUROSCI.5282-06.2007

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Language：English   Publishing type：Research paper (scientific journal)  

Autophagy is a mechanism to digest cells' own components, and its importance in many physiological and pathological processes is being recognized. But the molecular mechanism that regulates autophagy is not understood in detail. In the present study, we found that cholesterol depletion induces macroautophagy. The cellular cholesterol in human fibroblasts was depleted either acutely using 5mM methyl-beta-cyclodextrin or 10-20microg/ml nystatin for 1h, or metabolically by 20microM mevastatin and 200microM mevalonolactone along with 10% lipoprotein-deficient serum for 2-3 days. By any of these protocols, marked increase of LC3-II was detected by immunoblotting and by immunofluorescence microscopy, and the increase was more extensive than that caused by amino acid starvation, i.e., incubation in Hanks' solution for several hours. The induction of autophagic vacuoles by cholesterol depletion was also observed in other cell types, and the LC3-positive membranes were often seen as long tubules, >50microm in length. The increase of LC3-II by methyl-beta-cyclodextrin was suppressed by phosphatidylinositol 3-kinase inhibitors and was accompanied by dephosphorylation of mammalian target of rapamycin. By electron microscopy, autophagic vacuoles induced by cholesterol depletion were indistinguishable from those seen after amino acid starvation. These results demonstrate that a decrease in cholesterol activates autophagy by a phosphatidylinositol 3-kinase-dependent mechanism.

PubMed

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Language：English  

Autophagy is a mechanism to digest cells&#039; own components, and its importance in many physiological and pathological processes is being recognized. But the molecular mechanism that regulates autophagy is not understood in detail. In the present study, we found that cholesterol depletion induces macroautophagy. The cellular cholesterol in human fibroblasts was depleted either acutely using 5mM methyl-beta-cyclodextrin or 10-20microg/ml nystatin for 1h, or metabolically by 20microM mevastatin and 200microM mevalonolactone along with 10% lipoprotein-deficient serum for 2-3 days. By any of these protocols, marked increase of LC3-II was detected by immunoblotting and by immunofluorescence microscopy, and the increase was more extensive than that caused by amino acid starvation, i.e., incubation in Hanks&#039; solution for several hours. The induction of autophagic vacuoles by cholesterol depletion was also observed in other cell types, and the LC3-positive membranes were often seen as long tubules, &gt;50microm in length. The increase of LC3-II by methyl-beta-cyclodextrin was suppressed by phosphatidylinositol 3-kinase inhibitors and was accompanied by dephosphorylation of mammalian target of ra

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.bbrc.2006.06.074

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1242/jcs.02993

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1091/mbc.E05-07-0659

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1196/annals.1377.010

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Taylor and Francis Inc.  

DOI： 10.4161/auto.2904

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s00418-005-0061-5

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Language：Japanese  

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1073/pnas.221181998

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Language：Japanese   Publisher：日本組織細胞化学会  

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Language：Japanese   Publisher：(公社)日本生化学会  

Ichushi

J-GLOBAL

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Language：English  

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Language：Japanese   Publisher：日本組織細胞化学会  

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Language：Japanese   Publisher：日本組織細胞化学会  

Other Link:： http://search.jamas.or.jp/link/ui/2009061578

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Language：Japanese   Publisher：(公財)日本眼科学会  

Ichushi

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Language：English  

Other Link:： http://search.jamas.or.jp/link/ui/2008185316

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Language：English   Publishing type：Research paper, summary (international conference)  

Web of Science

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Language：Japanese   Publisher：(公財)日本眼科学会  

Ichushi

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Language：Japanese   Publisher：日本組織細胞化学会  

Other Link:： http://search.jamas.or.jp/link/ui/2006048317

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Language：English  

DOI： 10.1016/j.bbadis.2004.03.007

Web of Science

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Publisher：Springer Science and Business Media LLC  

Other Link:： http://link.springer.com/article/10.1007/s00418-004-0643-7/fulltext.html

DOI： 10.1007/s00418-004-0643-7

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Language：English  

DOI： 10.1016/S0887-8994(03)00267-4

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Language：Japanese  

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Event date： 2023.9

Presentation type：Poster presentation  

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Event date： 2023.7

Presentation type：Public lecture, seminar, tutorial, course, or other speech  

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Event date： 2023.6

Presentation type：Public lecture, seminar, tutorial, course, or other speech  

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Event date： 2023.3

Presentation type：Symposium, workshop panel (public)  

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Event date： 2022.11

Presentation type：Oral presentation (general)  

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Event date： 2022.9

Presentation type：Oral presentation (general)  

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Event date： 2022.6

Presentation type：Symposium, workshop panel (public)  

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Event date： 2022.3

Presentation type：Poster presentation  

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Event date： 2021.7

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

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Event date： 2021.3

Language：Japanese   Presentation type：Poster presentation  

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Event date： 2020.9

Language：English   Presentation type：Poster presentation  

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Event date： 2020.3

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

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Language：Japanese   Presentation type：Symposium, workshop panel (public)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Symposium, workshop panel (public)  

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Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：日本医科大学 武蔵境キャンパス  

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Language：English   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：藤田保険衛生大学  

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Language：Japanese   Presentation type：Poster presentation  

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