Ectopic Deposition Research Articles

Obesity genetics and cardiometabolic health: Potential for risk prediction.

The increasing burden of obesity worldwide and its effect on cardiovascular disease (CVD) risk is an opportunity for evaluation of preventive approaches. Both obesity and CVD have a genetic background and polymorphisms within genes which enhance expression of variant proteins that influence CVD in obesity. Genome-based prediction may therefore be a feasible strategy, but the identification of genetically driven risk factors for CVD manifesting as clinically recognized phenotypes is a major challenge. Clusters of such risk factors include hyperglycaemia, hypertension, ectopic liver fat, and inflammation. All involve multiple genetic pathways having complex interactions with variable environmental influences. The factors that make significant contributions to CVD risk include altered carbohydrate homeostasis, ectopic deposition of fat in muscle and liver, and inflammation, with contributions from the gut microbiome. A futuristic model depends on harnessing the predictive power of plausible genetic variants, phenotype reversibility, and effective therapeutic choices based on genotype-phenotype interactions. Inverting disease phenotypes into ideal cardiovascular health metrics could improve genetic and epigenetic assessment, and form the basis of a future model for risk detection and early intervention.

Production of YP170 Vitellogenins Promotes Intestinal Senescence in Caenorhabditis elegans.

During aging, etiologies of senescence cause multiple pathologies, leading to morbidity and death. To understand aging requires identification of these etiologies. For example, Caenorhabditis elegans hermaphrodites consume their own intestinal biomass to support yolk production, which in later life drives intestinal atrophy and ectopic yolk deposition. Yolk proteins (YPs; vitellogenins) exist as three abundant species: YP170, derived from vit-1–vit-5; and YP115 and YP88, derived from vit-6. Here, we show that inhibiting YP170 synthesis leads to a reciprocal increase in YP115/YP88 levels and vice versa, an effect involving posttranscriptional mechanisms. Inhibiting YP170 production alone, despite increasing YP115/YP88 synthesis, reduces intestinal atrophy as much as inhibition of all YP synthesis, which increases life span. By contrast, inhibiting YP115/YP88 production alone accelerates intestinal atrophy and reduces life span, an effect that is dependent on increased YP170 production. Thus, despite copious abundance of both YP170 and YP115/YP88, only YP170 production is coupled to intestinal atrophy and shortened life span. In addition, increasing levels of YP115/YP88 but not of YP170 increases resistance to oxidative stress; thus, longevity resulting from reduced vitellogenin synthesis is not attributable to oxidative stress resistance.

Computational Study of Calcium Phosphate Mineralization in Extracellular Vesicles

Calcification in bone, cartilage, and cardiovascular tissues involves the release of specialized extracellular vesicles (EVs) that promote mineral nucleation. The small size of the EVs, however, makes molecular level studies difficult, and consequently uncertainty exists on the role and function of these structures in directing mineralization. The lack of mechanistic understanding associated with the initiators of ectopic mineral deposition has severely hindered the development of potential therapeutic options. Here, we used multiscale molecular dynamics simulations to investigate the calcification within the EVs. Results show that Ca2+–HPO42– and phosphatidylserine complexes facilitate the early nucleation. Use of coarse-grained simulations allows investigations of Ca2+–PO43– nucleation and crystallization in the EVs. Systematic variation in the ion-to-water ratio shows that the crystallization and growth strongly depend on the enrichment of the ions and dehydration inside the EVs. Our investigations provide insights into the role of EVs on calcium phosphate mineral nucleation and growth in both physiological and pathological mineralization.

The Interaction between Laminin-332 and α3β1 Integrin Determines Differentiation and Maintenance of CAFs, and Supports Invasion of Pancreatic Duct Adenocarcinoma Cells.

Ranking among the most lethal tumour entities, pancreatic duct adenocarcinoma cells invade neighbouring tissue resulting in high incidence of metastasis. They are supported by tumour stroma fibroblasts which have undergone differentiation into cancer-associated fibroblasts (CAFs). Stiffness of cell substratum, cytokines, such as transforming growth factor-β (TGF-β), and stromal matrix proteins, such as laminin-332, are factors which promote CAF differentiation. In a spheroid culture system, differentiation of CAFs was analysed for laminin-332 production, laminin-binding integrin repertoire, adhesion and migration behaviour, and, in heterospheroids, for their interplay with the pancreatic duct adenocarcinoma AsPC-I cells. Our data reveal that CAFs produce laminin-332 thus contributing to its ectopic deposition within the tumour stroma. Moreover, CAF differentiation correlates with an increased expression of α3β1 integrin, the principal laminin-332-receptor. Beyond its role as novel CAF marker protein, integrin α3β1 crucially determines differentiation and maintenance of the CAF phenotype, as knock-out of the integrin α3 subunit reversed the CAF differentiated state. AsPC-I cells co-cultured in heterospheroids with integrin α3-deficient CAFs invaded less than from heterospheroids with wild-type CAFs. This study highlights the role of integrin α3β1 integrin-laminin-332 interaction of CAFs which promotes and sustains differentiation of CAFs and promotes carcinoma invasion.

Genome-Wide Identification of R2R3-MYB Transcription Factors Regulating Secondary Cell Wall Thickening in Cotton Fiber Development.

MYB proteins represent one of the largest transcription factor (TF) families in plants, some of which act as key transcriptional regulators of secondary cell wall (SCW) biosynthesis. Cotton (Gossypium hirsutum) fiber is thought to be an ideal single-cell model to study cell elongation and SCW biosynthesis. However, little knowledge regarding the TFs controlling fiber SCW biosynthesis, particularly for R2R3-MYBs is known. By far, no comprehensive genome-wide analysis of the secondary wall-associated R2R3-MYBs has been reported in cultivated tetraploid upland cotton. In this study, we identified 419 R2R3-MYB genes by systematically examining the cotton genome. A combination of phylogenetic, RNA-seq and co-expression analyses indicated that 36 R2R3-MYBs were either preferentially or highly expressed in 20 day post anthesis (dpa) fibers and are putative SCW regulators. Among these MYB genes, 22 MYBs are homologs of known SCW MYB proteins and the other 14 MYBs are novel proteins without prior reported SCW biosynthesis-related functions. Finally, we highlighted on the roles of two MYBs named GhMYB46_D13 and GhMYB46_D9, both of which displayed the highest expression in 20 dpa fibers. Expression of GhMYB46_D13 or GhMYB46_D9 individually in Arabidopsis resulted in ectopic SCW deposition in transgenic plants. Furthermore, both GhMYB46_D13 and GhMYB46_D9 were able to activate the cotton fiber SCW cellulose synthase gene promoters. Thus, we have identified 36 R2R3-MYBs as potential SCW regulators in cotton fibers that represent strong candidates for further functional studies during fiber development and SCW thickening.

BpNAC012 Positively Regulates Abiotic Stress Responses and Secondary Wall Biosynthesis.

NAC (NAM, ATAF1/2, and CUC2) transcription factors play important roles in plant biological processes and stress responses. Here, we characterized the functional roles of BpNAC012 in white birch (Betula platyphylla). We found that BpNAC012 serves as a transcriptional activator. Gain- and loss-of-function analyses revealed that the transcript level of BpNAC012 was positively associated with salt and osmotic stress tolerance. BpNAC012 activated the core sequence CGT[G/A] to induce the expression of abiotic stress-responsive downstream genes, including Δ-1-pyrroline-5-carboxylate synthetase, superoxide dismutase, and peroxidase, resulting in enhanced salt and osmotic stress tolerance in BpNAC012 overexpression transgenic birch lines. We also showed that BpNAC012 is expressed predominantly in mature stems and that RNA interference-induced suppression of BpNAC012 caused a drastic reduction in the secondary wall thickening of stem fibers. Overexpression of BpNAC012 activated the expression of secondary wall-associated downstream genes by directly binding to the secondary wall NAC-binding element sites, resulting in ectopic secondary wall deposition in the stem epidermis. Moreover, salt and osmotic stresses elicited higher expression levels of lignin biosynthetic genes and elevated lignin accumulation in BpNAC012 overexpression lines. These findings provide insight into the functions of NAC transcription factors.

HJURP antagonizes CENP-A mislocalization driven by the H3.3 chaperones HIRA and DAXX.

The centromere specific histone H3 variant CENP-A/CENH3 specifies where the kinetochore is formed in most eukaryotes. Despite tight regulation of CENP-A levels in normal cells, overexpression of CENP-A is a feature shared by various types of solid tumors and results in its mislocalization to non-centromeric DNA. How CENP-A is assembled ectopically and the consequences of this mislocalization remain topics of high interest. Here, we report that in human colon cancer cells, the H3.3 chaperones HIRA and DAXX promote ectopic CENP-A deposition. Moreover, the correct balance between levels of the centromeric chaperone HJURP and CENP-A is essential to preclude ectopic assembly by H3.3 chaperones. In addition, we find that ectopic localization can recruit kinetochore components, and correlates with mitotic defects and DNA damage in G1 phase. Finally, CENP-A occupancy at the 8q24 locus is also correlated with amplification and overexpression of the MYC gene within that locus. Overall, these data provide insights into the causes and consequences of histone variant mislocalization in human cancer cells.

Vitamin A Deficiency and the Lung.

Vitamin A (all-trans-retinol) is a fat-soluble micronutrient which together with its natural derivatives and synthetic analogues constitutes the group of retinoids. They are involved in a wide range of physiological processes such as embryonic development, vision, immunity and cellular differentiation and proliferation. Retinoic acid (RA) is the main active form of vitamin A and multiple genes respond to RA signalling through transcriptional and non-transcriptional mechanisms. Vitamin A deficiency (VAD) is a remarkable public health problem. An adequate vitamin A intake is required in early lung development, alveolar formation, tissue maintenance and regeneration. In fact, chronic VAD has been associated with histopathological changes in the pulmonary epithelial lining that disrupt the normal lung physiology predisposing to severe tissue dysfunction and respiratory diseases. In addition, there are important alterations of the structure and composition of extracellular matrix with thickening of the alveolar basement membrane and ectopic deposition of collagen I. In this review, we show our recent findings on the modification of cell-junction proteins in VAD lungs, summarize up-to-date information related to the effects of chronic VAD in the impairment of lung physiology and pulmonary disease which represent a major global health problem and provide an overview of possible pathways involved.

Defining lipid mediators of insulin resistance - controversies and challenges.

Essential elements of all cells, lipids play important roles in energy production, signalling and as structural components. Despite these critical functions, excessive availability and intracellular accumulation of lipid is now recognised as a major factor contributing to many human diseases, including obesity and diabetes. In the context of these metabolic disorders, ectopic deposition of lipid has been proposed to have deleterious effects of insulin action. While this relationship has been recognised for some time now, there is currently no unifying mechanism to explain how lipids precipitate the development of insulin resistance. This review summarises the evidence linking specific lipid molecules to the induction of insulin resistance, describing some of the current controversies and challenges for future studies in this field.

Lipohypertrophy due to HAART: a case series

A subset of HIV-1 infected patients undergoing Highly Active Antiretroviral Therapy (HAART) develops a lipodystrophy syndrome. It is characterised by loss of subcutaneous adipose tissue (face, limbs and buttocks) visceral fat accumulation and lipomatosis especially in dorsocervical area. In addition these patients show metabolic alteration implicative of metabolic syndrome particularly dyslipidaemia and insulin resistance. These alterations lead to enhanced cardiovascular risk and favour the development of diabetes in such patients. A complex combination of HIV infection, drug treatment related events and lipotoxicity appears to contribute to the development of lipodystrophy syndrome. Active lipolysis in subcutaneous fat combined with impaired storage capacity in subcutaneous depot leads to ectopic deposition of lipids either in visceral or in non-adipose sites. Lipotoxicity, a pathogenic factor in the lipodystrophy syndrome should be considered in the strategies for treating and /or preventing the morphological alterations and systemic metabolic disturbances associated with lipodystrophy.

Rapid nutritional promotion causes abnormal glucose metabolism

According to the survey conducted by the Chinese Center for Disease Control and Prevention, the prevalence of type 2 diabetes in China reached 10.9% in 2013, 20-fold increase over the early 1980s. In the recent two decades, the incidence of diabetes in our country has risen up significantly, which is related to catch up growth caused by the rapid promotion of nutrition. It has been revealed that catch up growth can result in thermogenesis suppression, dysfunction of adipose tissue, lipid ectopic deposition in skeletal muscle, liver inflammation, impaired function of intestinal-pancreatic axis and islet β cell injury, leading to visceral fat accumulation and insulin resistance, thus increasing the risk of type 2 diabetes. Therefore, it is of great significance to deeply explore the mechanism of catch up growth and to find effective intervention strategies for the prevention and treatment of type 2 diabetes in China.

Impact of Fetuin-A on progression of calcific aortic valve stenosis - The COFRASA - GENERAC study

BackgroundAortic stenosis (AS) is an active disease, but the determinants of AS progression remain largely unknown. Low levels of Fetuin-A, a powerful inhibitor of ectopic calcification, have been linked to ectopic calcium tissue deposition but its role in AS progression has not been clearly evaluated. MethodsIn our ongoing prospective cohort (COFRASA/GENERAC), serum Fetuin-A level was measured at baseline and AS severity was evaluated at baseline and yearly thereafter using echocardiography (mean pressure gradient (MPG)) and computed tomography (degree of aortic valve calcification (AVC)). Annual progression was calculated as [(final measurement-baseline measurement)/follow-up duration] for both MPG and AVC measurements. ResultsWe enrolled 296 patients (74 ± 10 years,73% men); mean follow-up duration was 3.0 ± 1.7 years. No correlation was found between baseline serum Fetuin-A (0.55 ± 0.15 g/L) and baseline AS severity (r = 0.25, p = 0.87 for MPG; r = 0.06, p = 0.36 for AVC). More importantly, there was no correlation between baseline serum Fetuin-A level and AS progression either assessed using MPG or AVC (both r = 0.01, p = 0.82). In bivariate analysis, after adjustment for age, gender, baseline AS severity, or valve anatomy, Fetuin-A was not associated with AS progression (all p > 0.20). The absence of link with AS progression was further confirmed by the absence of link betwen serum Fetuin-A and the occurrence of AS-related events (p = 0.17). ConclusionsIn a large prospective cohort of AS patients, serum Fetuin-A was not associated to hemodynamic or anatomic AS progression. Despite its capacity to inhibit ectopic calcium deposition, Fetuin-A serum level seemed to have minor influence on AS progression.

Maize Carbohydrate partitioning defective1 impacts carbohydrate distribution, callose accumulation, and phloem function.

Plants synthesize carbohydrates in photosynthetic tissues, with the majority of plants transporting sucrose to non-photosynthetic tissues to sustain growth and development. While the anatomical, biochemical, and physiological processes regulating sucrose long-distance transport are well characterized, little is known concerning the genes controlling whole-plant carbohydrate partitioning. To identify loci influencing carbon export from leaves, we screened mutagenized maize plants for phenotypes associated with reduced carbohydrate transport, including chlorosis and excessive starch and soluble sugars in leaves. Carbohydrate partitioning defective1 (Cpd1) was identified as a semi-dominant mutant exhibiting these phenotypes. Phloem transport experiments suggested that the hyperaccumulation of starch and soluble sugars in the Cpd1/+ mutant leaves was due to inhibited sucrose export. Interestingly, ectopic callose deposits were observed in the phloem of mutant leaves, and probably underlie the decreased transport. In addition to the carbohydrate hyperaccumulation phenotype, Cpd1/+ mutants overaccumulate benzoxazinoid defense compounds and exhibit increased tolerance when attacked by aphids. However, double mutant studies between Cpd1/+ and benzoxazinoid-less plants indicate that the ectopic callose and carbon hyperaccumulation are independent of benzoxazinoid production. Based on the formation of callose occlusions in the developing phloem, we hypothesize that the cpd1 gene functions early in phloem development, thereby impacting whole-plant carbohydrate partitioning.

Soluble CD200 in secretory phase endometriosis endometrial venules may explain endometriosis pathophysiology and provide a novel treatment target

Retrograde menstruation is common and in about 10% of women, endometrial tissues implant at ectopic sites and grow as endometriosis (EM) deposits. To date, there has been no marker to identify which patients have an endometrium that will generate deposits. Both endometrial regulatory T cells (Tregs) and increased stromal cell indoleamine 2,3-dioxygenase (IDO) have been implicated, and may suppress rejection by peritoneal NK cells, neutrophils, and cytotoxic macrophages. CD200 is a tolerance signaling molecule which promotes Tregs, IDO-producing macrophages, and can directly inhibit cytolytic natural killer (NK) cells and neutrophils. To determine if CD200 might be overexpressed in the endometrium of women with endometriosis, a pilot study using quantitative immunohistochemistry was done using uterine sections and EM deposits from hysterectomy patients. Both CD200 and CD200R proteins were detectable in endometriosis (EM) deposits and in endometrial epithelium and stroma. CD200 increased slightly in secretory phase whole endometrium of EM patients, but strikingly increased soluble CD200 (sCD200) absent sCD200R within venules typified both endometriosis deposits and secretory phase endometrial stromal venules and lymphatics in EM endometria compared to secretory phase NE endometria (P = 0.000006). In our opinion, accumulation of sCD200 in secretory phase endometrial blood vessels may explain development of ectopic deposits and quantifying sCD200 in menstrual blood may cases and identify predisposition to EM. Animal model studies are required to determine if antagonizing CD200 could be therapeutic.

Surgical Management of Multiple Nevus Lipomatosis Superficialis: A Case Report

Nevus lipomatosis superficialis is a rare skin lesion characterized by the ectopic dermal deposition of adipose tissue. While benign, it typically presents in the second to third decade of life as regional discomfort. We present the case of multiple lesions requiring serial surgical management.

Abstract 691: Mir-146a as a Modulator and Pathomechanistic Target of Vascular Calcification

Background: Arterial stiffness, which may develop due to vascular calcification, is a significant pathophysiological factor associated with arterial aging or diseases such as type-2 diabetes or end stage renal disease. With no effective therapy clinically available to date, molecular and epigenetic mechanisms of ectopic calcification in conduit arteries are receiving increasing attention to identify targets for therapeutical interference. Here we show that miR-146a may serve as a therapeutic candidate to counteract vascular calcification. Methods: Ectopic calcification was assessed in human aortic smooth muscle cells (AoSMCs) using Alizarin red and Von kossa stainings. The total calcium content in hydroxyapatite crystals was assessed using QuantiChrom TM calcium assay kit. The mRNA expression levels of BMP2, MSX2 and SORT1 were assessed by TaqMan real-time PCR. Results: The endogenous expression of miR-146a was significantly decreased and simultaneously ectopic calcium deposition was significantly increased in AoSMCs exposed to osteogenic stimulation. However, overexpression of miR-146a in AoSMCs cultured in vitro reduced the ectopic calcium deposits. Simultaneously, mRNA expression levels of osteogenic markers and drivers of calcification, such as BMP2, MSX2 and SORT1 - all predicted miR-146a target genes - were significantly reduced. Conversely, significantly increased calcium deposits were observed when miR-146a was inhibited in these cells in similar culture conditions with upregulated BMP2, MSX2 and SORT1 mRNA expression levels. Conclusion: The results suggest that miR-146a may serve as a modulator of AoSMC calcification and miR-146a supplementation may qualify as a therapeutic intervention to counteract vascular calcification due to aging, type-2 diabetes or end stage renal disease.

Alpha-syntrophin deficient mice are protected from adipocyte hypertrophy and ectopic triglyceride deposition in obesity

Alpha-syntrophin (SNTA) is a molecular adapter protein which is expressed in adipocytes. Knock-down of SNTA in 3T3-L1 preadipocytes increases cell proliferation, and differentiated adipocytes display small lipid droplets. These effects are both characteristics of healthy adipose tissue growth which is associated with metabolic improvements in obesity. To evaluate a role of SNTA in adipose tissue morphology and obesity associated metabolic dysfunction, SNTA deficient mice were fed a standard chow or a high fat diet. Mice deficient of SNTA had less fat mass and smaller adipocytes in obesity when compared to control animals. Accordingly, these animals did not develop liver steatosis and did not store excess triglycerides in skeletal muscle upon high fat diet feeding. SNTA−/− animals were protected from hyperinsulinemia and hepatic insulin resistance. Of note, body-weight, food uptake, and serum lipids were normal in the SNTA null mice. SNTA was induced in adipose tissues but not in the liver of diet induced obese and ob/ob mice. In human subcutaneous and visceral fat of seven patients SNTA was similarly expressed and was not associated with body mass index. Current data demonstrate beneficial effects of SNTA deficiency in obesity which is partly attributed to smaller adipocytes and reduced white adipose tissue mass. Higher SNTA protein in fat depots of obese mice may contribute to adipose tissue hypertrophy and ectopic lipid deposition which has to be confirmed in humans.

High dietary fat and sucrose result in an extensive and time-dependent deterioration in health of multiple physiological systems in mice

Obesity is associated with metabolic dysfunction, including insulin resistance and hyperinsulinemia, and with disorders such as cardiovascular disease, osteoporosis, and neurodegeneration. Typically, these pathologies are examined in discrete model systems and with limited temporal resolution, and whether these disorders co-occur is therefore unclear. To address this question, here we examined multiple physiological systems in male C57BL/6J mice following prolonged exposure to a high-fat/high-sucrose diet (HFHSD). HFHSD-fed mice rapidly exhibited metabolic alterations, including obesity, hyperleptinemia, physical inactivity, glucose intolerance, peripheral insulin resistance, fasting hyperglycemia, ectopic lipid deposition, and bone deterioration. Prolonged exposure to HFHSD resulted in morbid obesity, ectopic triglyceride deposition in liver and muscle, extensive bone loss, sarcopenia, hyperinsulinemia, and impaired short-term memory. Although many of these defects are typically associated with aging, HFHSD did not alter telomere length in white blood cells, indicating that this diet did not generally promote all aspects of aging. Strikingly, glucose homeostasis was highly dynamic. Glucose intolerance was evident in HFHSD-fed mice after 1 week and was maintained for 24 weeks. Beyond 24 weeks, however, glucose tolerance improved in HFHSD-fed mice, and by 60 weeks, it was indistinguishable from that of chow-fed mice. This improvement coincided with adaptive β-cell hyperplasia and hyperinsulinemia, without changes in insulin sensitivity in muscle or adipose tissue. Assessment of insulin secretion in isolated islets revealed that leptin, which inhibited insulin secretion in the chow-fed mice, potentiated glucose-stimulated insulin secretion in the HFHSD-fed mice after 60 weeks. Overall, the excessive calorie intake was accompanied by deteriorating function of numerous physiological systems.

Oleic Acid Protected Pancreatic β‐Cell Against Saturated Fatty Acid Induced Lipotoxicity

BackgroundThe loss of functional pancreatic β‐cell has played a critical role in the development of type 2 diabetes (T2DM). Chronic exposure to high free fatty acids (FFAs) in the context of hyperlipidemia or ectopic deposition of fat in pancreas is recognized as a causal factor for β‐cell dysfunction in T2DM. It is widely accepted that saturated FFAs, such as palmitic acid (PA), are responsible for β‐cell apoptosis, however, unsaturated FFAs, such as oleic acid (OA), are reported unharmful. In the present study, we investigated the PA induced intercellular toxicity and whether monounsaturated OA could counteract these detrimental effects when combined with PA. This work will give insights to the dietary therapy in T2DM.MethodsRat insulinoma cell line INS‐1E were incubated with 0.2 mM PA, 0.2 mM OA or the combination for 24 h. Cell viability was determined by CCK8 assay, and cell apoptosis was measured by flow cytometry, respectively. Western blot were performed to detect endoplasmic reticulum stress (ER stress) related proteins. The effects of OA on thapsigargin (Thp) induced ER stress of INS‐1E β‐cells were evaluated by CCK8 assay. The 24 h chronic insulin secretion was measured by Elisa.Result1) PA deteriorated cell viability of INS‐1E β‐cells in dose and time dependent manner. PA of 0.2 mM has remarkably decreased the cell viability (60%) compared to controls after 24 h incubation. Stimulation with OA showed no effect on cell viability but the combination of OA and PA robustly restored the viability to normal level. The proportion of apoptotic cells was increased to 43.5% after PA challenge for 24 h, whereas cosupplementation of OA dramatically rescued the INS‐1 cells from cell death. Consistently, OA alone has not induced cell apoptosis. 2) To explore the mechanism responsible for the protective role of OA, we focused on ER stress. OA alleviated PA‐triggered ER stress, evidenced by remarkably decreased protein levels of ER stress markers (CHOP and p‐PERK). Interestingly, classical ER stressor Thp declined the viability of INS‐1 cells, while OA was able to abrogate this effect, confirming its protective role in ER stress. 3) Furthermore, insulin secretion was increased when INS‐1E cells were incubated with PA plus OA, in comparison to either OA or PA alone, suggesting the trophic effect of combination treatment on the function of β‐cells. 4) On the other hand, withdrawal of PA after 24 h exposure, then addition of OA for a further 24 h showed no protective effects on cell viability. The time course showed that withdrawal of 1.0 mM PA after 6 h, 8h and 10 h exposure, and addition of OA for a further 18 h, 16 h and 14 h respectively, earlier addition of OA had better protective results, suggesting the early interact of OA with PA has played an important role in this scenario.ConclusionWe found that PA could induce lipotoxicity on INS‐1E β‐cells. OA alone has no detrimental effects on β‐cells, and the combination of OA and PA has great potential to protect β‐cells against PA‐induced apoptosis. The interaction with PA and subsequent suppression of ER stress may contribute to the OA mediated protective effects on lipotoxicity in INS‐1E β‐cells.Support or Funding InformationThis study was supported by the Program of National Natural Science Foundation of China (31571474), and the National Key Clinical Project.

Lipotoxicty in yeast: a focus on plasma membrane signalling and membrane contact sites.

Lipotoxicity is a pathophysiological process triggered by lipid overload. In metazoans, lipotoxicity is characterised by the ectopic deposition of lipids on organs other than adipose tissue. This leads to organ dysfunction, cell death, and is intimately linked to lipid-associated diseases such as cardiac dysfunction, atherosclerosis, stroke, hepatosteatosis, cancer and the metabolic syndrome. The molecules involved in eliciting lipotoxicity include FAs and their acyl-CoA derivatives, triacylglycerol (TG), diacylglycerol (DG), ceramides, acyl-carnitines and phospholipids. However, the cellular transport of toxic lipids through membrane contact sites (MCS) and vesicular mechanisms as well as lipid metabolism that progress lipotoxicity to the onset of disease are not entirely understood. Yeast has proven a useful model organism to study the molecular mechanisms of lipotoxicity. Recently, the Rim101 pathway, which senses alkaline pH and the lipid status at the plasmamembrane, has been connected to lipotoxicity. In this review article, we summarise recent research advances on the Rim101 pathway and MCS in the context of lipotoxicity in yeast and present a perspective for future research directions.