Protein Digests and Pure Peptides from Chia Seed Prevented Adipogenesis and Inflammation by Inhibiting PPARγ and NF-κB Pathways in 3T3L-1 Adipocytes

The objective was to evaluate the mechanisms of digested total proteins (DTP), albumin, glutelin, and pure peptides from chia seed (Salvia hispanica L.) to prevent adipogenesis and its associated inflammation in 3T3-L1 adipocytes. Preadipocytes (3T3-L1) were treated during differentiation with either DTP or digested albumin or glutelin (1 mg/mL) or pure peptides NSPGPHDVALDQ and RMVLPEYELLYE (100 µM). Differentiated adipocytes also received DTP, digested albumin or glutelin (1 mg/mL), before (prevention) or after (inhibition) induced inflammation by addition of conditioned medium (CM) from inflamed macrophages. All treatments prevented adipogenesis, reducing more than 50% the expression of PPARγ and to a lesser extent lipoprotein lipase (LPL), fatty acid synthase (FAS), sterol regulatory element-binding protein 1 (SREBP1), lipase activity and triglycerides. Inflammation induced by CM was reduced mainly during prevention, while DTP decreased expression of NF-κB (−48.4%), inducible nitric oxide synthase (iNOS) (−46.2%) and COX-2 (−64.5%), p < 0.05. Secretions of nitric oxide, PGE2 and TNFα were reduced by all treatments, p < 0.05. DTP reduced expressions of iNOS (−52.1%) and COX-2 (−66.4%). Furthermore, digested samples and pure peptides prevented adipogenesis by modulating PPARγ and additionally, preventing and even inhibiting inflammation in adipocytes by inhibition of PPARγ and NF-κB expression. These results highlight the effectiveness of digested total proteins and peptides from chia seed against adipogenesis complications in vitro.     

Actions of peroxovanadate or tungstate on glucose transport by isolated rat adipocytes

The effects of peroxovanadate or tungstate on 3-O-methylglucose uptake were characterized using isolated rat adipocytes to elucidate the mechanism(s) of their actions. The stimulatory effect of peroxovanadate was observed from 1 μmol/L and reached the maximum at about 100 μmol/L. The concentration showing the half-maximal effect was approximately 16 μmol/L. The maximal response of peroxovanadate was 1.19 times higher than that of insulin significantly (P < 0.01). On the other hand, the stimulatory effect of tungstate was seen only at the higher concentrations of 10–30 mmol/L Judging from the experiments using different tungsten compounds, tungstic acid (WO₄^2-) appeared responsible for the effect. The effects of 20 mmol/L tungstate and 20 nmol/L insulin were not additive. The stimulatory effects of 1 mmol/L peroxovanadate, 20 mmol/L tungstate or 20 nmol/L insulin were not seen in the adipocytes deprived of ATP by exposure to 2 mmol/L KCN. The adipocytes which had been stimulated with insulin and further exposed to 2 mmol/L KCN were used to test whether or not peroxovanadate works directly on the function of glucose transporters. In such cells on which GLUT4-rich transporters were rendered immobile, the effect of peroxovanadate was not observed. These results indicate that the effects of peroxovanadate or tungstate are ATP or energy dependent and may be exerted through the mechanism analogous to that of insulin action, and suggest that peroxovanadate does not directly activate the function of GLUT4.     

Signalling pathways identified in salivary glands from primary Sjögren’s syndrome patients reveal enhanced adipose tissue development

A characteristic feature of primary Sjögren’s syndrome (pSS) is the destruction of salivary and lacrimal glands mediated by mononuclear cell infiltration. Adipocytes can also occupy a large portion of the salivary gland (SG) tissue area, although little is known about their significance in pSS. We have previously investigated adipose tissue infiltration in SG biopsies from pSS patients and non-SS sicca controls. Our findings indicated the distinct incidence of adipose tissue replacement in pSS patients, where adipocytes were detected in interleukin (IL) 6 rich regions. We now aimed to examine the development of adipocytes in the SG microenvironment, and delineate their possible involvement in immune reactions. A microarray analysis was performed on SG from 6 pSS patients and 6 non-SS controls, where the expression levels of genes involved in adipose tissue development, inflammatory responses, and lymphoma development were assessed. Real-time PCR was carried out on SG from 14 pSS patients and 15 non-SS controls to account for IL6, IL10, and IL17 mRNA levels. Immunohistochemical staining of frozen SG tissue using IL17 was also conducted. Our results indicate signalling pathways identified in SG of pSS patients displayed genes leading to prominent adipose tissue development and reduced mitochondrial fatty acid beta-oxidation (ARID5B, OXCT1, BDH1, SOX8, HMGCS2, FTO, ECHS1, PCCA, ACADL and ACADVL), inflammatory responses (IL1R1, IL7R, IL10RA, IL15, IL18RAP, CCL2, CCL5, CCL22, CXCR6, CD14, and CD48), and lymphoma development via JAK-STAT signalling (STAT2, TYK2, EBI3, FAS, TNFRSF1B, MAP3K8, HMOX1, LTB, TNF, STAT1, and BAK1). Genes involved in interferon production and signalling were also detected (IRF1, IRF9, and IRF7), in addition to IL6, IL10, and IL17. Higher mRNA levels of IL6, IL17 and IL10 were observed in the SG of pSS patients compared to controls. Moreover, IL17 positive cells were detected mostly interstitially in the SG and around adipocytes, also within the focal infiltrates. In conclusion, adipocyte development seems to be more prominent in the SG of pSS patients, where adipose tissue replacement is also evident. Whether this is due to disease progression, or the repair process, remains to be investigated. Detection of IL17 positive adipocytes in the target organ suggests their involvement in immune reactions.     

MAP kinases and mTOR mediate insulin-induced phosphorylation of Insulin Receptor Substrate-1 on serine residues 307, 612 and 632

Aim/hypothesis Insulin-induced IRS-1 serine phosphorylation could be physiologically important to regulate insulin action. In a hyperinsulinaemic state such as obesity or Type 2 diabetes, this phosphorylation could be modified and exacerbate insulin resistance. We aimed at identifying serine residues in IRS-1 phosphorylated in response to insulin stimulation and at determining the involved kinases.Methods 3T3-L1 adipocytes, muscle and adipose tissue of mice were subjected to Western Blot analysis with phosphospecific antibodies to identify phosphorylation sites in IRS-1 following insulin treatment. Pharmacological inhibitors were used to determine the serine kinases involved in this phosphorylation.Results In 3T3-L1 adipocytes, insulin promoted the phosphorylation of serine 307, 612 and 632 with Serine^612/632 more rapidly phosphorylated than Serine³⁰⁷. Insulin-induced phosphorylation of Serine³⁰⁷ was dependent on the activation of a PI 3-kinase/mTOR pathway. The phosphorylation of Serine^612/632 required the activation of the MAP kinase pathway following short-term insulin stimulation and activation of the PI 3-kinase/mTOR pathway following prolonged insulin stimulation. Phosphorylation of Serine³⁰⁷ and Serine⁶³² occurred in vivo in skeletal muscle and white adipose tissue of mice injected with insulin and was dependent on the activation of mTOR. Moreover, inhibition of mTOR led to a persistent PI 3-kinase activation by insulin.Conclusion/Interpretation Insulin-induced IRS-1 serine phosphorylation is a complex process involving different sites and kinases. This complexity could be physiologically important to accurately regulate insulin signalling. Abnormal phosphorylation of these serine residues in hyperinsulinaemic state could participate in the down-regulation of insulin signalling.Abbreviations PI 3-kinase phosphatidylinositol 3-kinase - mTOR mammalian target of rapamycin - APS adaptor with a PH and SH2 domains - Shc Src Homology Collagen - SH2 Src Homology 2 - PTB phosphotyrosine binding - MAP mitogen-activated protein - MEK mitogen-activated protein kinase kinase - PKB protein kinase B - PDGF platelet derived growth factor - JNK c-Jun NH2 terminal kinase - PMA phorbol myristate acetate - PIP3 phosphatidylinositol 3,4,5 triphosphates     

Crosstalk between adipokines and myokines in fat browning

Skeletal muscle is the largest organ determining whole‐body insulin sensitivity and metabolic homoeostasis. Adaptive changes of skeletal muscle in response to physical activity include adjustments in the production and secretion of muscle‐derived bioactive factors, known as myokines, such as myostatin, IL‐4, IL‐6, IL‐7 and IL‐15, myonectin, follistatin‐like 1 or leukaemia inhibitory factor. These myokines not only act locally in the muscle in an autocrine/paracrine manner, but also are released to the bloodstream as endocrine factors to regulate physiological processes in other tissues. Irisin, derived from the cleavage of FNDC5 protein, constitutes a myokine that induces myogenesis and fat browning (switch of white adipocytes to brown fat‐like cells) together with a concomitant increase in energy expenditure. Besides being a target for irisin actions, the adipose tissue also constitutes a production site of FNDC5. Interestingly, irisin secretion from subcutaneous and visceral fat depots is decreased by long‐term exercise training and fasting, suggesting a discordant regulation of FNDC5/irisin in skeletal muscle and adipose tissue. Accordingly, our group has recently reported that the adipokine leptin differentially regulates FNDC5/irisin expression in skeletal muscle and fat, confirming the crosstalk between both tissues. Moreover, irisin secretion and function are regulated by other myokines, such as follistatin or myostatin, as well as by other adipokines, including fibroblast growth factor 21 and leptin. Taken together, myokines have emerged as novel molecular mediators of fat browning and their activity can be modulated by adipokines, confirming the crosstalk between skeletal muscle and adipose tissue to regulate thermogenesis and energy expenditure.     

Mature adipocytes in bone marrow protect myeloma cells against chemotherapy through autophagy activation

A major problem in patients with multiple myeloma is chemotherapy resistance, which develops in myeloma cells upon interaction with bone marrow stromal cells. However, few studies have determined the role of bone marrow adipocytes, a major component of stromal cells in the bone marrow, in myeloma chemotherapy resistance. We reveal that mature human adipocytes activate autophagy and upregulate the expression of autophagic proteins, thereby suppressing chemotherapy-induced caspase cleavage and apoptosis in myeloma cells. We found that adipocytes secreted known and novel adipokines, such as leptin and adipsin. The addition of these adipokines enhanced the expression of autophagic proteins and reduced apoptosis in myeloma cells. In vivo studies further demonstrated the importance of bone marrow-derived adipocytes in the reduced response of myeloma cells to chemotherapy. Our findings suggest that adipocytes, adipocyte-secreted adipokines, and adipocyte-activated autophagy are novel targets for combatting chemotherapy resistance and enhancing treatment efficacy in myeloma patients.     

跑台运动训练和停训对去卵巢大鼠腰椎骨密度和骨髓脂肪细胞数目的影响

目的:观察中等强度跑台运动训练和停训对去卵巢大鼠腰椎骨密度、骨组织形态学和骨髓脂肪细胞数目的影响。方法:将60只成年雌性SD大鼠按体重分层后随机分为假手术组、去卵巢静止组和去卵巢运动组,每组20只。去卵巢运动组每周进行4次时间45 min、速度18 m/min、跑道倾角5°的跑台训练。持续训练14周后,将各组大鼠再次按体重分层后随机分为两个亚组,即假手术16周(Sham-16)组和假手术32周(Sham-32)组、去卵巢16周(OVX-16)组和去卵巢32周(OVX-32)组以及去卵巢运动(EX)组和停训组(DEX)。Sham-16、OVX-16和EX三组大鼠在末次训练结束36-48小时内,Sham-32、OVX-32和DEX三组大鼠在停训16周时,用双能Χ线骨密度仪活体检测大鼠腰椎骨密度,常规HE染色对第2腰椎(L2)进行组织形态学观察。结果:(1)训练结束时,OVX-16组L2脂肪细胞数目显著高于Sham-16组和EX组,腰椎骨密度显著低于Sham-16组和EX组。(2)停训16周时,OVX-32组腰椎骨密度与Sham-32组比较显著下降,L2脂肪细胞数目显著增加,而DEX组与OVX-32组比较无显著性差异。结论:中等强度跑台运动对去卵巢大鼠腰椎骨密度下降的减缓效应和对骨髓脂肪细胞数目增加的抑制效应在停训16周后未能保持。     

Lipophilic Micronutrients and Adipose Tissue Biology

Lipophilic micronutrients (LM) constitute a large family of molecules including several vitamins (A, D, E, K) and carotenoids. Their ability to regulate gene expression is becoming increasingly clear and constitutes an important part of nutrigenomics. Interestingly, adipose tissue is not only a main storage site for these molecules within the body, but it is also subjected to the regulatory effects of LM. Indeed, several gene regulations have been described in adipose tissue that could strongly impact its biology with respect to the modulation of adipogenesis, inflammatory status, or energy homeostasis and metabolism, among others. The repercussions in terms of health effects of such regulations in the context of obesity and associated pathologies represent an exciting and emerging field of research. The present review will focus on the regulatory effects of vitamin A, D, E and K as well as carotenoids on adipose tissue biology and physiology, notably in the context of obesity and associated disorders.     

现代吸脂技术采集脂肪混合物在脂肪干细胞制备领域中的应用

背景：目前用于整容的吸脂术发展很快,但为了脂肪干细胞应用而进行的综合吸脂术研究和比较尚未见报道。 目的：对比目前各种类型脂肪抽取技术的特点以及对基质血管层、脂肪细胞、脂肪干细胞的数量和存活率等指标的影响,评价出细胞活性高、适合进行脂肪干细胞制备、储存及临床科学研究的吸脂技术。 方法：作者分别采用检索关键词“adipose-derived stem cel s,ADSCs, liposuction,SAL,UAL,PAL,WAL”和“脂肪干细胞、脂肪抽取术、负压吸脂术、超声辅助吸脂术、震动辅助吸脂术、水动力辅助吸脂术”检索了PubMed数据库、中国知网全文期刊数据库和美国NIH 临床试验数据库,排除与研究目的无关和内容重复者,保留50篇文献进行进一步分析。 结果与结论：目前可应用于脂肪间充质干细胞采集的现代吸脂技术主要有负压吸脂、超声辅助吸脂、震动辅助吸脂、水动力辅助吸脂。其中负压吸脂、超声辅助吸脂技术、水动力辅助吸脂技术3类技术采集的脂肪混合物中可以分离出脂肪干细胞且具有较高的活性,可以用作自体细胞辅助移植技术和再生疗法。这4类技术虽然各有特点,有必要进一步研究这些吸脂技术获得的脂肪干细胞的活性、遗传性状稳定性、分化能力等系统性对比数据,为未来的再生医学工程提供更准确完善的支持。