Transmembrane protein 126B protects against high fat diet (HFD)-induced renal injury by suppressing dyslipidemia via inhibition of ROS

The role of exercise in improving hyperlipidemia-renal injuries induced by a high-fat diet: a literature review

A diet that is high in sugar and fat is a precursor to various chronic diseases, especially hyperlipidemia. Patients with hyperlipidemia have increased levels of plasma free fatty acids and an ectopic accumulation of lipids. The kidney is one of the main organs affected by this disease and, recently, there have been more studies conducted on renal injury caused by hyperlipidemia. The main pathological mechanism is closely related to renal lipotoxicity. However, in different kidney cells, the reaction mechanism varies due to the different affinities of the lipid receptors. At present, it is believed that in addition to lipotoxicity, hyperlipidemia induced-renal injury is also closely related to oxidative stress, endoplasmic reticulum stress, and inflammatory reactions, which are the result of multiple factors. Exercise plays an important role in the prevention of various chronic diseases and recently emerging researches indicated its positive effects to renal injury caused by hyperlipidemia. However, there are few studies summarizing the effects of exercise on this disease and the specific mechanisms need to be further explored. This article summarizes the mechanisms of hyperlipidemia induced-renal injury at the cellular level and discusses the ways in which exercise may regulate it. The results provide theoretical support and novel approaches for identifying the intervention target to treat hyperlipidemia induced-renal injury.

High-Fat Diet-Induced Renal Proximal Tubular Inflammatory Injury: Emerging Risk Factor of Chronic Kidney Disease

Nowadays, with the improvements in living standards and changes in living habits, high-fat diet (HFD) has become much more common in the populations worldwide. Recent studies have shown that HFD could induce lipid accumulation, and structural and functional abnormalities, accompanied by the release of large amounts of pro-inflammatory cytokines, in proximal tubular epithelial cells (PTECs). These findings indicate that, as an emerging risk factor, PTEC injury-induced by HFD may be closely related to inflammation; however, the potential mechanisms underlying this phenomenon is still not well-known, but may involve the several inflammatory pathways, including oxidative stress-related signaling pathways, mitochondrial dysfunction, the myeloid differentiation factor 2/Toll like receptor 4 (MD2/TLR4) signaling pathway, the ERK1/2-kidney injury molecule 1 (KIM-1)-related pathway, and nuclear factor-κB (NF-κB) activation, etc., and the detailed molecular mechanisms underlying these pathways still need further investigated in the future. Based on lipid abnormalities-induced inflammation is closely related to the development and progression of chronic kidney disease (CKD), to summarize the potential mechanisms underlying HFD-induced renal proximal tubular inflammatory injury, may provide novel approaches for CKD treatment.

Myo-inositol improves growth performance and regulates lipid metabolism of juvenile Chinese mitten crab (Eriocheir sinensis) fed different percentage of lipid

This study evaluated the effects of dietary myo-inositol (MI) on growth performance, antioxidant status and lipid metabolism of juvenile Chinese mitten crab (Eriocheir sinensis) fed different percentage of lipid. Crabs (4·58 (sem 0·05) g) were fed four diets including a normal lipid diet (N, containing 7 % lipid and 0 mg/kg MI), N with MI supplementation (N + MI, containing 7 % lipid and 1600 mg/kg MI), a high lipid diet (H, containing 13 % lipid and 0 mg/kg MI) and H with MI supplementation (H + MI, containing 13 % lipid and 1600 mg/kg MI) for 8 weeks. The H + MI group showed higher weight gain and specific growth rate than those in the H group. The dietary MI could improve the lipid accumulations in the whole body, hepatopancreas and muscle as a result of feeding on the high dietary lipid (13 %) in crabs. Besides, the crabs fed the H + MI diets increased the activities of antioxidant enzymes but reduced the malondialdehyde content in hepatopancreas compared with those fed the H diets. Moreover, dietary MI enhanced the expression of genes involved in lipid oxidation and exportation, yet reduced lipid absorption and synthesis genes expression in the hepatopancreas of crabs fed the H diet, which might be related to the activation of inositol 1,4,5-trisphosphate receptor (IP3R)/calmodulin-dependent protein kinase kinase-β (CaMKKβ)/adenosine 5'-monophosphate-activated protein kinase (AMPK) signalling pathway. This study demonstrates that MI could increase lipid utilisation and reduce lipid deposition in the hepatopancreas of E. sinensis fed a high lipid diet through IP3R/CaMKKβ/AMPK activation. This work provides new insights into the function of MI in the diet of crustaceans.

TMP- SSurface2: A Novel Deep Learning-Based Surface Accessibility Predictor for Transmembrane Protein Sequence

Transmembrane protein (TMP) is an important type of membrane protein that is involved in various biological membranes related biological processes. As major drug targets, TMPs’ surfaces are highly concerned to form the structural biases of their material-bindings for drugs or other biological molecules. However, the quantity of determinate TMP structures is still far less than the requirements, while artificial intelligence technologies provide a promising approach to accurately identify the TMP surfaces, merely depending on their sequences without any feature-engineering. For this purpose, we present an updated TMP surface residue predictor TMP-SSurface2 which achieved an even higher prediction accuracy compared to our previous version. The method uses an attention-enhanced Bidirectional Long Short Term Memory (BiLSTM) network, benefiting from its efficient learning capability, some useful latent information is abstracted from protein sequences, thus improving the Pearson correlation coefficients (CC) value performance of the old version from 0.58 to 0.66 on an independent test dataset. The results demonstrate that TMP-SSurface2 is efficient in predicting the surface of transmembrane proteins, representing new progress in transmembrane protein structure modeling based on primary sequences. TMP-SSurface2 is freely accessible at https://github.com/NENUBioCompute/TMP-SSurface-2.0.

Dietary Supplementation of Astaxanthin Improved the Growth Performance, Antioxidant Ability and Immune Response of Juvenile Largemouth Bass (Micropterus salmoides) Fed High-Fat Diet

High-fat diet (HFD) usually induces oxidative stress and astaxanthin is regarded as an excellent anti-oxidant. An 8-week feeding trial was conducted to investigate the effects of dietary astaxanthin supplementation on growth performance, lipid metabolism, antioxidant ability, and immune response of juvenile largemouth bass (Micropterus salmoides) fed HFD. Four diets were formulated: the control diet (10.87% lipid, C), high-fat diet (18.08% lipid, HF), and HF diet supplemented with 75 and 150 mg kg^-1 astaxanthin (HFA1 and HFA2, respectively). Dietary supplementation of astaxanthin improved the growth of fish fed HFD, also decreased hepatosomatic index and intraperitoneal fat ratio of fish fed HFD, while having no effect on body fat. Malondialdehyde content and superoxide dismutase activity were increased in fish fed HFD, astaxanthin supplementation in HFD decreased the oxidative stress of fish. The supplementation of astaxanthin in HFD also reduced the mRNA levels of Caspase 3, Caspase 9, BAD, and IL15. These results suggested that dietary astaxanthin supplementation in HFD improved the growth performance, antioxidant ability and immune response of largemouth bass.

Ablation of TMEM126B protects against oxygen-glucose deprivation/reoxygenation-induced injuries of PC12 cells via maintaining mitochondrial anti-apoptotic functions

Ischemia reperfusion (I/R) injury is a key contributing factor to the pathogenic mechanism involved in cerebral infarction. Transmembrane protein 126b (TMEM126B), a mitochondrial complex I assembly factor, has been reported to have an intimate association with disease progression, but is little known in ischemia stroke. The present study was designed to explore the effects of TEME126B on oxygen-glucose deprivation/reoxygenation (OGD/R)-induced neuronal PC12 cells. The mRNA level of TMEM126B was determined using qRT-PCR. The levels of ROS, MDA, and SOD, as well as inflammatory cytokines, were measured using corresponding commercial kits. Cell apoptosis rate was assayed by flow cytometry analysis, and the apoptosis-related proteins were measured using western blotting. ATP production measured by colorimetric reaction and mitochondrial membrane potential measured by JC-1 staining were conducted to determine mitochondrial dysfunction. The results showed that TMEM126B was upregulated upon I/R injury in vitro and in clinical, and was positively corrected with the degree of oxidative stress. TMEM126B knockdown significantly reduced oxidative stress and inflammation in OGD/R-induced PC12 cells. TMEM126B knockdown also attenuated cell apoptosis rate, accompanied with increased expressions of Bcl-2, XIAP and cleaved PARP-1, and decreased expressions of Bax, cleaved caspase 3 and cleaved caspase 9. Furthermore, TMEM126B knockdown exhibited cytoprotective roles through alleviating mitochondrial dysfunction, as assessed by ATP production and mitochondrial membrane potential. Collectively, this study indicates that TMEM126B knockdown protects against OGD/R-induced neuronal injuries through relieving oxidative stress, inflammation, apoptosis and mitochondria dysfunction, which provides a promising target for ischemic stroke treatment.

Modeling Diet-Induced Metabolic Syndrome in Rodents

Standardized animal models represent one of the most valuable tools available to understand the mechanism underlying the metabolic syndrome (MetS) and to seek for new therapeutic strategies. However, there is considerable variability in the studies conducted with this essential purpose. This review presents an updated discussion of the most recent studies using diverse experimental conditions to induce MetS in rodents with unbalanced diets, discusses the key findings in metabolic outcomes, and critically evaluates what we have been learned from them and how to advance in the field. The study includes scientific reports sourced from the Web of Science and PubMed databases, published between January 2013 and June 2020, which used hypercaloric diets to induce metabolic disorders, and address the impact of the diet on metabolic parameters. The collected data are used as support to discuss variables such as sex, species, and age of the animals, the most favorable type of diet, and the ideal diet length to generate metabolic changes. The experimental characteristics propose herein improve the performance of a preclinical model that resembles the human MetS and will guide researchers to investigate new therapeutic alternatives with confidence and higher translational validity.

Ablation of TMEM126B protects against heart injury via improving mitochondrial function in high fat diet (HFD)-induced mice

The mitochondrial dysfunction in the pathogenesis of myocardial damage associated with high fat diet (HFD)-induced obesity remains largely unknown. Transmembrane protein 126B (TMEM126B), as a complex I assembly factor, plays a key role in regulating mitochondrial function. In the present study, the effects of TMEM126B on mitochondrial function were investigated using genetic knockout approach in HFD-induced mouse models with obesity. We found that TMEM126B was significantly increased in HFD-treated cardiac samples. Genetic ablation of TMEM126B alleviated HFD-mediated metabolic disorder and heart injury. TEM results suggested that cardiac mitochondrial integrity was improved in TMEM126B knockout mice compared with the wild type (WT) mice after HFD challenge. Additionally, the mitochondrial dysfunction induced by HFD was alleviated in mice with TMEM126B knockout, as evidenced by the decreased protein expression levels of dynamic-related protein-1 (DRP1) and fission-1 (FIS1) and increased expression of mitofusin-1 (MFN1). The mitochondrial impairments were further confirmed in palmitic acid (PA)-incubated cardiomyocytes, as evidenced by the down-regulated membrane potential and ATP levels, and by the up-regulated mitochondrial reactive oxygen species (ROS) production and DNA damage, which were significantly reversed by TMEM126B knockdown in vitro. Finally, TMEM126B ablation suppressed mitochondrial-dependent apoptotic death in the hearts of HFD mice. Therefore, TMEM126B led to mitochondrial impairments, contributing to the pathogenesis of HFD-induced cardiac injury, and blockage of TMEM126B could inhibit mitochondrial dysfunction, paving the road to new therapeutic modalities for the prevention of obesity-associated heart injury.