ORP8 acts as a lipophagy receptor to mediate lipid droplet turnover

Lipophagy, the selective engulfment of lipid droplets (LDs) by autophagosomes for lysosomal degradation, is critical to lipid and energy homeostasis. Here we show that the lipid transfer protein ORP8 is located on LDs and mediates the encapsulation of LDs by autophagosomal membranes. This function of ORP8 is independent of its lipid transporter activity and is achieved through direct interaction with phagophore-anchored LC3/GABARAPs. Upon lipophagy induction, ORP8 has increased localization on LDs and is phosphorylated by AMPK, thereby enhancing its affinity for LC3/GABARAPs. Deletion of ORP8 or interruption of ORP8-LC3/GABARAP interaction results in accumulation of LDs and increased intracellular triglyceride. Overexpression of ORP8 alleviates LD and triglyceride deposition in the liver of ob/ob mice, and Osbpl8-/- mice exhibit liver lipid clearance defects. Our results suggest that ORP8 is a lipophagy receptor that plays a key role in cellular lipid metabolism.

Series of experiments performed with the droplet evaporation method on low potencies

Homeopathic preparations in low potencies, containing still measurable quantities of the starting substance, constitute a unique research field in homeopathic basic research. Here a series of experiments is presented carried out by means of the droplet evaporation method (DEM), investigating the specificity of the method, and presumed effects of the succussion procedure applied in the production of homeopathic preparations. Methods:DEM analysis consisted in the evaporation of droplets of the potencies perse placed on microscope slides. Resulting patterns were photographed. Images were evaluated by means of ImageJ software, by measuring grey level distribution, texture, and fractality. The experimentation consisted of four series: (i) screening (1x­6x potencies from 19 substances), (ii) differentiation experiments (2x­6x potencies of Echinacea, Baptisia, Luffa, and Spongia), (iii) differentiation between succussed (100 or 10 times) and unsuccussed samples (Echinacea 2x, Baptisia 3x, Baptisia 4x, Luffa 4x, and Spongia 6x). (iv) investigation of the influence upon the patterns of single compounds present in a remedy complex. The experimental set-up stability was examined by systematic positive control experiments. Results:(i) Homeopathic preparations of mineral origin showed the greatest form variety, whereas those of vegetal origin created fractal patterns in the potency range 2x­4x. (ii) Differentiation of potencies of different origin at the same dilution level was possible from 2x to 4x. (iii) In all potency levels, succussed (100 and 10 times) and unsuccussed variants could be significantly differentiated. Significant differences between all variants were found in some cases in potency levels 4x and higher. In general, application of succussion reduced size, homogeneity, and complexity of the DEM patterns. (iv) Patterns of a remedy complex Luffa 4x -Mercurius bijodatum 9x showed a clear predominance of the Luffa 4x; however also the second component, present in a much lower concentration, influenced significantly the pattern of the remedy complex as also differed significantly from the pattern of succussed water control. Conclusions:The results suggest that DEM is a suitable tool for scientific investigation of homeopathic preparations in the low potency range. DEM might be applied to assess further research questions, such different potentization procedures (vessel shape, overhead volume, material), storing time, and difference between batches.

Formation of Self-organized Structures in Drying Droplets: a Promising Analytical Tool for Homeopathy Basic Research

The droplet evaporation method (DEM) is based on the evaporation-induced pattern formation in droplets and is applied mainly for medical diagnosis[1].Here, we present aseries of experiments performed by our team showing DEMs potential also forhomeopathy basic research, in particular, for the investigation of(i) low potencies, (ii) low potency complexes (physical model), and (iii) the action of high potencies (plant-based model).Methods:(i) DEM differentiated significantly between Luffa, Baptisia, Echinacea, and Spongiauntil 4x[2]. Furthermore, the patterns varied in function of the numberof succussion strokes (0, 10, or 100) applied during potentization[3]. The performance of chaotic succussions vs. laminar flow vs. slight mixing during the potentization of Viscum album quercus3x influenced the DEM patterns; the chaotic succussions reduced, whereas laminar flow enhanced the patterns complexity vs. the unsuccussed control.(ii) The addition of Mercurius bijodatus9x to Luffa4x changed significantly the DEM patterns, even if the material quantity present in the 9x potency lied far beyond that of ultrapure water.(iii) Leakages obtained by placing healthy or arsenic-damaged wheat-seeds into Arsenicum album45x orheat-damaged intoZincum metallicum30c vs. water created significantly different DEM structures [4, 5]. Results:The damaged seeds put into the potency created structures characterized by a higher complexity than those obtained from damaged seeds put into control water. Furthermore, the potency action seemed to increase with rising numbers ofsuccussion strokes applied during potentization,ascould be shown by means of DEM patterns and germination rate using the same wheat-seed model[6].In all our studies, the pattern evaluation was computerized (texture and fractal analysis performed by means of ImageJ) or based on deep-learning algorithms and the robustness of the experimental system was checked by means of systematic control experiments.Conclusion:DEM together with other similarmethods has also been reviewed by our team for what concerns theapplication in homeopathy basic research[7].

Exercise regulates lipid metabolism via lipophagy and its molecular mechanisms / 生理学报

Lipophagy is a kind of selective autophagy, which can selectively identify and degrade lipid droplets and plays an important role in regulating cellular lipid metabolism and maintaining intracellular lipid homeostasis. Exercise can induce lipophagy and it is also an effective means of reducing body fat. In this review, we summarized the relationship between exercise and lipophagy in the liver, pancreas, adipose tissue, and the possible molecular mechanisms to provide a new clue for the prevention and treatment of fatty liver, obesity and other related metabolic diseases by exercise.

New observations on the effect of camellia oil on fatty liver disease in rats / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Camellia oil has become an important plant oil in China in recent years, but its effects on non-alcoholic fatty liver disease (NAFLD) have not been documented. In this study, the effects of camellia oil, soybean oil, and olive oil on NAFLD were evaluated by analyzing the fatty acid profiles of the plant oils, the serum lipids and lipoproteins of rats fed different oils, and by cytological and ultrastructural observation of the rats' hepatocytes. Analysis of fatty acid profiles showed that the polyunsaturated fatty acid (PUFA) n-6/n-3 ratio was 33.33 in camellia oil, 12.50 in olive oil, and 7.69 in soybean oil. Analyses of serum lipids and lipoproteins of rats showed that the levels of total cholesterol and low-density lipoprotein cholesterol in a camellia oil-fed group (COFG) were lower than those in an olive oil-fed group (OOFG) and higher than those in a soybean oil-fed group (SOFG). However, only the difference in total cholesterol between the COFG and SOFG was statistically significant. Cytological observation showed that the degree of lipid droplet (LD) accumulation in the hepatocytes in the COFG was lower than that in the OOFG, but higher than that in the SOFG. Ultrastructural analysis revealed that the size and number of the LDs in the hepatocytes of rats fed each of the three types of oil were related to the degree of damage to organelles, including the positions of nuclei and the integrity of mitochondria and endoplasmic reticulum. The results revealed that the effect of camellia oil on NAFLD in rats was greater than that of soybean oil, but less than that of olive oil. Although the overall trend was that among the three oil diets, those with a lower n-6/n-3 ratio were associated with a lower risk of NAFLD, and the effect of camellia oil on NAFLD was not entirely related to the n-6/n-3 ratio and may have involved other factors. This provides new insights into the effect of oil diets on NAFLD.

Cryptotanshinone Inhibits Lipid Accumulation in Differentiating 3T3-L1 Preadipocytes by Down-regulating C/EBP-α, PPAR-γ, FAS, Perilipin A, and STAT-3 / 계명의대학술지

Differentiation of preadipocyte, also named adipogenesis, leads to the phenotype of mature adipocyte that is filled with many lipid droplets. Excessive lipid accumulation in adipocytes leads to the development of obesity. In this study, we investigated the effect of 11 different natural compounds on lipid accumulation during the differentiation of 3T3-L1 preadipocytes into 3T3-L1 adipocytes. Strikingly, among the natural compounds, cryptotanshinone at 10 µM most strongly reduced triglyceride (TG) contents in 3T3-L1 cells after 8 days of the differentiation. Furthermore, cryptotanshinone at 10 µM significantly suppressed lipid accumulation in 3T3-L1 cells after 8 days of the differentiation. Cryptotanshinone at 1 to 10 µM tested did not affect the survival of 3T3-L1 cells after 8 days of the differentiation. On mechanistic levels, cryptotanshinone time-differentially decreased the expression levels of CCAAT/enhancer-binding protein-α (C/EBP-α), peroxisome proliferator-activated receptor-γ (PPAR-γ), fatty acid synthase (FAS), and perilipin A but also the phosphorylation levels of signal transducer and activator of transcription-3 (STAT-3) during the 3T3-L1 cell differentiation. Taken together, these findings demonstrate that cryptotanshinone inhibits lipid accumulation in differentiating 3T3-L1 cells, which appears to be mediated through the reduced expression and/or phosphorylation levels of C/EBP-α, PPAR-γ, FAS, Perilipin A, and STAT-3.

Inhibition of ER Stress by 2-Aminopurine Treatment Modulates Cardiomyopathy in a Murine Chronic Chagas Disease Model

Trypanosoma cruzi infection results in debilitating cardiomyopathy, which is a major cause of mortality and morbidity in the endemic regions of Chagas disease (CD). The pathogenesis of Chagasic cardiomyopathy (CCM) has been intensely studied as a chronic inflammatory disease until recent observations reporting the role of cardio-metabolic dysfunctions. In particular, we demonstrated accumulation of lipid droplets and impaired cardiac lipid metabolism in the hearts of cardiomyopathic mice and patients, and their association with impaired mitochondrial functions and endoplasmic reticulum (ER) stress in CD mice. In the present study, we examined whether treating infected mice with an ER stress inhibitor can modify the pathogenesis of cardiomyopathy during chronic stages of infection. T. cruzi infected mice were treated with an ER stress inhibitor 2-Aminopurine (2AP) during the indeterminate stage and evaluated for cardiac pathophysiology during the subsequent chronic stage. Our study demonstrates that inhibition of ER stress improves cardiac pathology caused by T. cruzi infection by reducing ER stress and downstream signaling of phosphorylated eukaryotic initiation factor (P-elF2α) in the hearts of chronically infected mice. Importantly, cardiac ultrasound imaging showed amelioration of ventricular enlargement, suggesting that inhibition of ER stress may be a valuable strategy to combat the progression of cardiomyopathy in Chagas patients.

Forskolin induced remodeling of lipid droplets in rat adipocytes / 生理学报

Adipose tissue is the main energy reserve of the body. When energy is required, adipocyte triglycerides stored in lipid droplets (LDs) are broken down by lipase, and free fatty acids are released to supply the physiological need. Intracellular LDs are active metabolic organelles in mammalian cells, particularly in adipocytes. The present study was aimed to investigate the morphological changes of LDs and the alternation of LD-associated perilipin family proteins during long-term lipolysis stimulated by forskolin. Primary differentiated adipocytes derived from epididymal fat pads of Sprague-Dawley (SD) rats were incubated in the presence or absence of 1 μmol/L forskolin for 24 h. Content of glycerol released to the culture medium was determined by a colorimetric assay and served as an index of lipolysis. Morphological changes of LDs were observed by Nile red staining. The mRNA level of perilipin family genes was detected by quantitative real-time PCR. The protein level and subcellular localization were examined by immunoblotting and immunofluorescence staining, respectively. The results showed that forskolin induced sustained lipolysis in differentiated adipocytes. The morphology of LDs changed in a time-dependent manner. Large clustered LDs became gradually smaller in size and eventually disappeared; in contrast, peripheral micro-LDs increased gradually in number until the cytoplasm was filled with numerous micro-LDs. The protein level of the perilipin family proteins showed obvious alternation. Mature adipocytes physiologically expressed a very low level of Plin2 protein, whereas in adipocytes stimulated with lipolytic forskolin, the protein and mRNA levels of Plin2 were significantly increased, and the increased Plin2 was specifically bound to the surface of LDs. During chronic stimulation of forskolin, the mRNA level of Plin3 was unchanged, but the mRNA levels of Plin1, Plin4 and Plin5 were significantly decreased. These results suggest that the morphology of LDs and perilipin family proteins on the surface of LDs are significantly altered during long-term lipolysis stimulated by forskolin, representing a dynamic process of the remodeling of LDs.

Effects of Lonicera caerulea extract on adipocyte differentiation and adipogenesis in 3T3-L1 cells and mouse adipose-derived stem cells (MADSCs) / 한국영양학회지

PURPOSE: Obesity is a major health problem of global significance because it is clearly associated with an increased risk of health problems, such as nonalcoholic fatty liver disease (NAFLD), diabetes, cardiovascular diseases, and cancer. Lonicera caerulea (LC) originates from high mountains or wet areas and has been used as a traditional medicine in northern Russia, China, and Japan. LC contains a range of bioactive constituents, such as vitamins, minerals, and polyphenols. This study examined the anti-obesity effects of LC during differentiation in preadipocytes. METHODS: The cell viability assay was performed after the differentiation of 3T3-L1 cells for 7 days. Oil Red O staining was used to visualize the changes in lipid droplets in 3T3-L1 cells and mouse adipose-derived stem cells (MADSCs). The mRNA expression of obesity-related genes was determined by quantitative real-time PCR. RESULTS: According to the results of Oil Red O staining, the lipid levels and size of lipid droplets in the adipocytes were reduced and the LC extract (LCE, 0.25–1 mg/mL) markedly inhibited adipogenesis in a dose-dependent manner. The treatment of LCE also decreased the mRNA expression of peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer binding protein-α (C/EBPα), and sterol regulatory element binding protein 1 (SREBP1) in 3T3-L1 cells. Western blot analysis showed that the PPARγ, C/EBPα, and SREBP1 protein levels in both 3T3-L1 and MADSC were reduced in a dose-dependent manner. CONCLUSION: These results suggest that LCE can inhibit adipogenic differentiation through the regulation of adipogenesis-related markers.

Correlation of spontaneous adipocyte generation with osteogenic differentiation of porcine skin-derived stem cells

The objective of this study was to examine effects of spontaneous adipocyte generation on osteogenic differentiation of porcine skin-derived stem cells (pSSCs). Correlation between osteogenic differentiation and adipocyte differentiation induced by osteocyte induction culture was determined using different cell lines. Osteogenic differentiation efficiency of pSSCs was then analyzed by controlling the expression of adipocyte-specific transcription factors during osteogenic induction culture. Among four cell lines, pSSCs-II had the lowest lipid droplet level but the highest calcium content (p < 0.05). It also expressed significantly low levels of peroxisome proliferator-activated receptor gamma 2 (PPARγ2) and adipocyte protein 2 (aP2) mRNAs but very high levels of runt-related transcription factor 2 (Runx2) and alkaline phosphatase (ALP) mRNAs as osteogenic makers (p < 0.05). Oil red O extraction was increased by 0.1 µM troglitazone (TGZ) treatment but decreased by 50 µM bisphenol A diglycidyl ether (BADGE) (p < 0.05). Calcium content was drastically increased after BADGE treatment compared to that in osteogenic induction control and TGZ-treated pSSCs (p < 0.05). Relative expression levels of PPARγ2 and aP2 mRNAs were increased by TGZ but decreased by BADGE. Expression levels of Rucx2 and ALP mRNAs, osteoblast-specific marker genes, were significantly increased by BADGE treatment (p < 0.05). The expression level of BCL2 like 1 was significantly higher in BADGE-treated pSSCs than that in TGZ-treated ones (p < 0.05). The results demonstrate that spontaneous adipocyte generation does not adversely affect osteogenic differentiation. However, reducing spontaneous adipocyte generation by inhibiting PPARγ2 mRNA expression can enhance in vitro osteogenic differentiation of pSSCs.

LC/MS-based Analysis of Bioactive Compounds from the Bark of Betula platyphylla var. japonica and Their Effects on Regulation of Adipocyte and Osteoblast Differentiation

Betula platyphylla var. japonica (Betulaceae), also known as Asian white birch, is an endemic medicinal tree, the bark of which has been used in Chinese traditional medicine for the treatment of various inflammatory diseases. In our continuing search for bioactive compounds from Korean natural resources, a phytochemical investigation of the bark of B. platyphylla var. japonica led to the isolation of 7-oxo-β-sitosterol (1) and soyacerebroside I (2) from its ethanol extract as main components by liquid chromatography (LC)/mass spectrometry (MS)-based analysis. The structures of isolates were identified by comparison of ¹H and ¹³C nuclear magnetic resonance spectroscopic data and physical data with the previously reported values and LC/MS analyses. To the best of our knowledge, this is the first study to demonstrate that the isolated compounds, 7-oxo-β-sitosterol and soyacerebroside I, were isolated in B. platyphylla var. japonica. We examined the effects of the isolates on the regulation of adipocytes and osteoblast differentiation. These isolates (1 and 2) produced fewer lipid droplets compared to the untreated negative control in Oil Red O staining of the mouse mesenchymal stem cell line without altering the amount of alkaline phosphatase staining. The results demonstrated that both compounds showed marginal inhibitory effects on adipocyte differentiation but did not affect osteoblast differentiation.

Olmsted Syndrome Caused by a Heterozygous p.Gly568Val Missense Mutation in TRPV3 Gene

Olmsted syndrome (OS) is a rare congenital skin disorder characterized by severe palmoplantar and periorificial keratoderma, alopecia, onychodystrophy, and severe pruritus. Recently, pathogenic ‘gain-of-function‘ mutations of the transient receptor potential vanilloid 3 gene (TRPV3), which encodes a cation channel involved in keratinocyte differentiation and proliferation, hair growth, inflammation, pain and pruritus, have been identified to cause OS. Due to the rarity, the pattern of inheritance of OS is still unclear. We report a case of OS in a 3-year-old Korean girl and its underlying gene mutation. The patient presented with a disabling, bilateral palmoplantar keratoderma with onychodystrophy. She also exhibited pruritic eczematous skin lesions around her eyes, ears and gluteal fold. Genetic analysis identified a heterozygous p.Gly568Val missense mutation in the exon 13 of TRPV3. To our knowledge, this is the first case of OS in the Korean population showing a missense mutation p.Gly573Ser.

The effects of Brassica juncea L. leaf extract on obesity and lipid profiles of rats fed a high-fat/high-cholesterol diet

BACKGROUND/OBJECTIVES: Obesity is a global health problem of significant importance which increases mortality. In place of anti-obesity drugs, natural products are being developed as alternative therapeutic materials. In this study, we investigated the effect of Brassica juncea L. leaf extract (BLE) on fat deposition and lipid profiles in high-fat, high-cholesterol diet (HFC)-induced obese rats. MATERIALS/METHODS: Male Sprague-Dawley rats were divided into four groups (n = 8 per group) according to diet: normal diet group (ND), high-fat/high-cholesterol diet group (HFC), HFC with 3% BLE diet group (HFC-A1), and HFC with 5% BLE diet group (HFC-A2). Each group was fed for 6 weeks. Rat body and adipose tissue weights, serum biochemical parameters, and tissue lipid contents were determined. The expression levels of mRNA and proteins involved in lipid and cholesterol metabolism were determined by reverse transcription polymerase chain reaction and western blot analysis, respectively. RESULTS: The HFC-A2 group showed significantly lower body weight gain and food efficiency ratio than the HFC group. BLE supplementation caused mesenteric, epididymal, and total adipose tissue weights to decrease. The serum levels of triglyceride, total cholesterol, and low-density lipoprotein cholesterol were significantly reduced, and high-density lipoprotein cholesterol was significantly increased in rats fed BLE. These results were related to lower glucose-6-phosphate dehydrogenase, acetyl-coA carboxylase, and fatty acid synthase mRNA expression, and to higher expression of the cholesterol 7α-hydroxylase and low density lipoprotein-receptor, as well as increased protein levels of peroxisome proliferator-activated receptor α. Histological analysis of the liver revealed decreased lipid droplets in HFC rats treated with BLE. CONCLUSIONS: Supplementation of HFC with 3% or 5% BLE inhibited body fat accumulation, improved lipid profiles, and modulated lipogenesis- and cholesterol metabolism-related gene and protein expression.

The lipid droplet: A conserved cellular organelle

The lipid droplet (LD) is a unique multi-functional organelle that contains a neutral lipid core covered with a phospholipid monolayer membrane. The LDs have been found in almost all organisms from bacteria to humans with similar shape. Several conserved functions of LDs have been revealed by recent studies, including lipid metabolism and trafficking, as well as nucleic acid binding and protection. We summarized these findings and proposed a hypothesis that the LD is a conserved organelle.

Morphological Characteristics of Residual Skin Surface Components Collected from the Surface of Facial Skin in Women of Different Age

BACKGROUND: Problems of skin aging and its prevention currently attract increasing attention with the growth of human life expectancy. The morphology of the stratum corneum (SC) is well known, but investigation of age-related changes of its structure is difficult in the absence of non-invasive sampling methods. The residual skin surface components (RSSC) that overlay the SC can be easily collected non-invasively. OBJECTIVE: The aim of this study was to examine morphology of RSSC samples collected from the surface of facial skin of healthy female volunteers of different age. METHODS: RSSC samples were non-invasively collected from 53 adult female volunteers (22 aged in the range 18∼25 years and 31 aged in the range 50∼73 years). The samples were analysed microscopically. RESULTS: Distinct age-related changes were determined for lipid droplet size, corneocyte desquamation level and lipid crystal count. There was a significant (p=0.0006) decrease in lipid droplet size among older women. Similarly, significantly (p=0.0401) lower lipid crystal numbers were present in the older group. Conversely, corneocyte desquamation was significantly higher (p=0.0007) in older women. No age-related difference in microbial presence in the RSSC could be detected. Result patterns were generally similar to those previously found in male volunteers; however gender-related differences in the absolute values were revealed. CONCLUSION: Non-invasively collected RSSC samples allow identifying age-related changes on facial skin surface. The results of this study highlight gender-dependence of distinct elements of age-associated impairment of epidermal barrier and can be employed for developing new approaches to prevent changes associated with skin aging.

Ultrastructural Changes in Skeletal Muscle of Infants with Mitochondrial Respiratory Chain Complex I Defects

BACKGROUND AND PURPOSE: The pathogenesis of mitochondrial disease (MD) involves the disruption of cellular energy metabolism, which results from defects in the mitochondrial respiratory chain complex (MRC). We investigated whether infants with MRC I defects showed ultrastructural changes in skeletal muscle. METHODS: Twelve infants were enrolled in this study. They were initially evaluated for unexplained neurodegenerative symptoms, myopathies, or other progressive multiorgan involvement, and underwent muscle biopsies when MD was suspected. Muscle tissue samples were subjected to biochemical enzyme assays and observation by transmission electron microscopy. We compared and analyzed the ultrastructure of skeletal muscle tissues obtained from patients with and without MRC I defects. RESULTS: Biochemical enzyme assays confirmed the presence of MRC I defects in 7 of the 12 patients. Larger mitochondria, lipid droplets, and fused structures between the outer mitochondrial membrane and lipid droplets were observed in the skeletal muscles of patients with MRC I defects. CONCLUSIONS: Mitochondrial functional defects in MRC I disrupt certain activities related to adenosine triphosphate synthesis that produce changes in the skeletal muscle. The ultrastructural changes observed in the infants in this study might serve as unique markers for the detection of MD.

The Role of Macrophage Lipophagy in Reverse Cholesterol Transport

Macrophage cholesterol efflux is a central step in reverse cholesterol transport, which helps to maintain cholesterol homeostasis and to reduce atherosclerosis. Lipophagy has recently been identified as a new step in cholesterol ester hydrolysis that regulates cholesterol efflux, since it mobilizes cholesterol from lipid droplets of macrophages via autophagy and lysosomes. In this review, we briefly discuss recent advances regarding the mechanisms of the cholesterol efflux pathway in macrophage foam cells, and present lipophagy as a therapeutic target in the treatment of atherosclerosis.

Intracellular Remodeling and Accumulation of Aberrant Lysosomes in Differentiation of Tonsil-Derived Mesenchymal Stem Cells into Parathyroid-Like Cells

Differentiation of mesenchymal stem cells (MSC) into a variety of cell lineages such as adipocytes, osteocytes, and chondrocytes is often accompanied up-regulation of autophagy. In our study, we demonstrated that the expression of autophagy-associated proteins (p-Beclin 1, LC3A, LC3B, p-AMPK, p-mTOR and ATG3, ATG7, and ATG12-5) over a period of time was hardly distinguishable from control tonsil-derived MSC (TMSC). Despite the unnoticeable difference in autophagy activation between differentiated TMSC (dTMSC) and the control (cTMSC), we reported significant changes in intracellular compositions in differentiated TMSC into functional parathyroid-like cells secreting parathyroid hormone (PTH). By using transmission electron microscopy (TEM), we observed accumulation of multivesicular bodies (MVB) comprising small, degraded compartments densely accumulated as dark granular or amorphous clumps, multilamellar bodies and lipid droplets in dTMSC. However, no such structures were found in cTMSC. These results suggest that differentiation of TMSC into parathyroid-like cells producing PTH hormone is hardly dependent on autophagy activation in the beginning of our conditions. Furthermore, our results of intracellular remodeling and accumulated endo-lysosomal storage bodies in the later stages of TMSC differentiation present a possible role of the structures in PTH secretion.

Omic studies reveal the pathogenic lipid droplet proteins in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is an epidemic metabolic condition driven by an underlying lipid homeostasis disorder. The lipid droplet (LD), the main organelle involved in neutral lipid storage and hydrolysis, is a potential target for NAFLD therapeutic treatment. In this review, we summarize recent progress elucidating the connections between LD-associated proteins and NAFLD found by genome-wide association studies (GWAS), genomic and proteomic studies. Finally, we discuss a possible mechanism by which the protein 17β-hydroxysteroid dehydrogenase 13 (17β-HSD13) may promote the development of NAFLD.

Papel das espécies reativas de oxigênio na biogênese de corpúsculos lipídicos e alterações oxidativas de seus componentes durante a sepse experimental / Role of reactive oxygen species in the biogenesis of lipid bodies and oxidative changes of their components during experimental sepsis

Sepse é a resposta inflamatória sistêmica secundária a um processo infeccioso e caracteriza-se por um desbalanço entre as respostas pró e antiinflamatórias. Em anos recentes tornou-se evidente que o estresse oxidativo e a disfunção mitocondrial desempenham papéis importantes na falência de múltiplos órgãos associada à sepse. Além disso, alterações no metabolismo lipídico, com aumento na formação de corpúsculos lipídicos (CLs) tem sido demonstradas em modelos experimentais de sepse e também em amostras de pacientes sépticos. No entanto, pouco se sabe sobre a associação entre estes dois eventos na sepse, a saber, a produção de ROS e a biogênese de CLs e qual o impacto do estresse oxidativo sobre estas organelas. No presente trabalho demonstrou-se que o tratamento com antioxidante específico para ROS de origem mitocondrial bem como a inibição, farmacológica ou genética, da NADPH oxidase é capaz de reduzir significativamente a biogênese de CLs, indicando um papel importante de ROS, produzido por ambas as vias, nos mecanismos de formação destas organelas induzidas pelo estímulo com LPS + IFNγ. Demonstramos também que os componentes lipídicos dos CLs são alvos da ação de ROS e sofrem peroxidação.

Estes lipídios peroxidados induzem modificações proteicas principalmente em proteínas localizadas na periferia dos CLs fato este observado tanto in vitro quanto in vivo. As alterações dos componentes moleculares dos CLs foram dependentes da ativação da NADPH oxidase uma vez que o pré tratamento com apocinina reduz a peroxidação lipídica e previne a modificação proteica induzidas por lipídios peroxidados in vitro. A interação entre CLs e mitocôndrias foram frequentes em nossos modelos. Alterações ultraestruturais nas mitocôndrias foram observadas principalmente naquelas que estabeleciam associação com os CLs em células peritoniais de animais submetidos ao CLP. No fígado, a sepse experimental induziu um aumento acentuado de CLs e em paralelo com alterações ultraestruturais de elétron-densidade ao longo do tempo que apontam para mudanças na composição lipídica destas organelas. Tanto o acúmulo de CLs quanto alterações do metabolismo hepático estão correlacionados com a gravidade do modelo de sepse. Em conjunto estes resultados demonstram uma associação entre o estresse oxidativo, biogênese de CLs e alterações oxidativas de seus componentes, e sugerem que este mecanismo possa contribuir para o dano tecidual durante a sepse. (AU)