The spontaneously formed structures of physiologically relevant lipid model membranes made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, ...1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1′-rac-glycerol) and 1,2-hexanoyl-sn-glycero-3-phosphocholine have been evaluated in depth using small angle neutron scattering. Although a common molar ratio of long- to short- chain phospholipids (~4) as reported in many bicellar mixtures was used, discoidal bicelles were not found as the major phase throughout the range of lipid concentration and temperature studied, indicating that the required condition for the formation of bicelle is the immiscibility between the long- and short- chain lipids, which were in the gel and Lα phases, respectively, in previous reports. In this study, all lipids are in the Lα phase. The characterization outcome suggests that the spontaneous structures tie strongly with the physical parameters of the system such as melting transition temperature of the long-chain lipid, total lipid concentration and charge density of the system. Multilamellar vesicles, unilamellar vesicles, ribbons and perforated lamellae can be obtained based on the analysis of the small angle neutron scattering results, leading to the construction of structural diagrams. This report provides the important map to choose suitable lipid systems for the structural study of membrane-associated proteins, design of theranostic nanocarriers or other related research fields.
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•The spontaneous structural diagrams of POPC bicellar mixtures are similar to those of common bicellar systems in Lα phase.•High temperature promotes vesiculation.•Addition of charged POPG effectively unbinds the multilamellar vesicles into unilamellar vesicles POPC/DHPC mixture.•Swellable perforated lamellae with long-range ordered are found in the high-concentration (≥ 7.5 wt%) POPC/POPG/DHPC sample.•ULV and perforated lamellae coexist at 4.0 wt%, R = 0.1, POPC/POPG/DHPC sample throughout the full temperature range.
The particle size of m-ZrO2 is decreased with the increase of amount of added seeds ranged from 10 to 60nm, the more the amount of crystal, the smaller particles.
•The seeds promoted the growth of ...m-ZrO2 and inhibited the formation of t-ZrO2.•The amounts of seeds can influence the sizes of m-ZrO2 particles.•The mechanisms with precursors, energy and the oil/water method are well presented.
Uniform monoclinic zirconia (m-ZrO2) nanoparticles were prepared by the oil/water interface method combined with seeding technique. In this synthesis, ZrOCl2 was modified by a surfactant and then hydrolyzed in the cyclohexane/water interface. Zirconia nanoparticles were obtained through adjusting various reaction parameters such as temperature, reaction time and amount of m-ZrO2 seeds. The formation of m-ZrO2 nanoparticles was obviously promoted by addition of the seeds and their size was tuned by controlling the amount of m-ZrO2 seeds. These suggest formation of the m-ZrO2 nanoparticles is controlled by the surface-deposition reaction. More importantly, due to the seeding effect, m-ZrO2 NPs were preferentially achieved in the shortened reaction time, or even at lowered temperature. Based on the above facts, the formation process of m-ZrO2 was discussed from the aspects of precursors, Gibbs free energy and the oil/water interface system.
Parkinson's Disease (PD) affects a significant amount of elderlies around the world. The progression and effectiveness of medication can be inferred from changes or improvements of gait in patients. ...Vertical ground reaction force is a common used measure to classify gait. In this study, such data from a publicly available dataset is used to classify gait between PD patients and healthy control subjects of similar ages. The data were preprocessed by normalization, splitting into standard time units and then converted to images. Classification was done using a stacked 2-dimensional and 1-dimenisonal convolutional neural network. Our model achieved 88.7% accuracy, an improvement of 5.3% over the next best performing model that was published.
Abstract
Protein synthesis is one of the most energy consuming process in the cell. Oncogenic kinases (e.g. EGFR/HER2, BCR/ABL and BRAF) play a central role in reprogramming translation and energy ...metabolism in neoplasia, whereby cancer cells must provide sufficient ATP to support increased levels of protein synthesis required for neoplastic growth. The downstream mechanisms that link translational machinery and energy homeostasis in cancer, however, remain largely unknown.
We found that widely used anti-diabetics (biguanides) abrogate adaptations to EGFR/HER2 inhibitor-induced energetic stress, which results in synergistic anti-neoplastic effects both in vitro and in vivo. In turn, breast cancer cells in which 4E-BP1/2 expression was abrogated by CRISPR were partially resistant to the combination of EGFR/HER2 inhibitors and biguanides. This was paralleled by the inability of the drugs to inhibit the eIF4F complex assembly and translation of mRNAs encoding important metabolic regulators including those involved in serine biogenesis (PHGDH, PSAT1) and one carbon metabolism (MTHFD1L).
Comparable results were observed when BRAF and BCR/ABL inhibitors were combined with biguanides, which suggests that translational regulation of metabolic genes via the mTORC1/4E-BE/eIF4E pathway plays a major role in energy stress response in cancer.
Together our findings demonstrate that the eIF4F complex is an important mediator of metabolic adaptation in response to the combination of biguanides and clinically-used kinase inhibitors and suggest that the efficiency of such anti-cancer strategies are dependent on the integrity of the translation initiation machinery.
Citation Format: Laura Hulea, Marie Cargnello, Simon-Pierre Gravel, Young Im, Shannon McLaughlan, Yunhua Zhao, Jenna Ching, Yutian Cai, Ola Larsson, Michael Ohh, Josie Ursini-Siegel, Julie St-Pierre, Michael Pollak, Ivan Topisirovic. eIF4F links translation to energy stress response in cancer. abstract. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr A31.
Protein synthesis (or mRNA translation) is a major step in the regulation of gene expression and one of the most energy consuming processes in the cell. eIF5A is activated by a unique ...post-translational modification called hypusination (modification of Lys50 on eIF5A to hypusine), which is catalyzed bydeoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH). eIF5Ahypusination is thought to play a significant role in translation, but little is known about its regulation. Our recent genome-wide interrogation of the translatome identified DOHH mRNA as a potential translational target of themechanistic/mammalian target of rapamycin (mTOR). We were able to validatethese findings and demonstrate that treatment with mTOR inhibitors, rapamycin and torin1 causes a substantial decrease in DOHH protein levels. Using proteasome inhibitors and measuring mRNA levels by RT-qPCR, we concluded the mTOR neither controls stability of DOHH protein nor the transcription of the corresponding gene. We next conducted polysome-profiling experiments using mTOR inhibitors, which revealed that mTOR regulates DOHH expression at the level of translation. Since both mTOR and eIF5A hypusination are often found to be upregulated in cancer, and we established the link between mTOR and eIF5A hypusination, we hypothesized the DOHH/eIF5A pathway at least in part mediates oncogenic effects of mTOR. Using soft agar assay, we demonstrated that DOHH depletion was sufficient to attenuate anchorage-independent growth induced by hyperactivated mTOR signaling. These findings suggest that DOHH and consequently eIF5A hypusination may play a major role in mTOR-driven oncogenesis.
Melanoma can be stratified into unique subtypes based on distinct pathologies. The acral/mucosal melanoma subtype is characterized by aberrant and constitutive activation of the proto-oncogene ...receptor tyrosine kinase C-KIT, which drives tumorigenesis. Treatment of these melanoma patients with C-KIT inhibitors has proven challenging, prompting us to investigate the downstream effectors of the C-KIT receptor. We determined that C-KIT stimulates MAP kinase-interacting serine/threonine kinases 1 and 2 (MNK1/2), which phosphorylate eukaryotic translation initiation factor 4E (eIF4E) and render it oncogenic. Depletion of MNK1/2 in melanoma cells with oncogenic C-KIT inhibited cell migration and mRNA translation of the transcriptional repressor SNA/1 and the cell cycle gene CCNE1. This suggested that blocking MNK1/2 activity may inhibit tumor progression, at least in part, by blocking translation initiation of mRNAs encoding cell migration proteins. Moreover, we developed an MNK1/2 inhibitor (SEL201), and found that SEL201-treated KIT-mutant melanoma cells had lower oncogenicity and reduced metastatic ability. Clinically, tumors from melanoma patients harboring K/T mutations displayed a marked increase in MNK1 and phospho-eIF4E. Thus, our studies indicate that blocking MNK1/2 exerts potent antimelanoma effects and support blocking MNK1/2 as a potential strategy to treat patients positive for K/T mutations.
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