Inflammation is a network of complex processes involving a variety of metabolic and signaling pathways aiming at healing and repairing damage tissue, or fighting infection. However, inflammation can ...be detrimental when it becomes out of control. Inflammatory mediators involve cytokines, bioactive lipids and lipid-derived metabolites. In particular, the simple sphingolipids ceramides, sphingosine 1-phosphate, and ceramide 1-phosphate have been widely implicated in inflammation. However, although ceramide 1-phosphate was first described as pro-inflammatory, recent studies show that it has anti-inflammatory properties when produced in specific cell types or tissues. The biological functions of ceramides and sphingosine 1-phosphate have been extensively studied. These sphingolipids have opposing effects with ceramides being potent inducers of cell cycle arrest and apoptosis, and sphingosine 1-phosphate promoting cell growth and survival. However, the biological actions of ceramide 1-phosphate have only been partially described. Ceramide 1-phosphate is mitogenic and anti-apoptotic, and more recently, it has been demonstrated to be key regulator of cell migration. Both sphingosine 1-phosphate and ceramide 1-phosphate are also implicated in tumor growth and dissemination. The present review highlights new aspects on the control of inflammation and cell migration by simple sphingolipids, with special emphasis to the role played by ceramide 1-phosphate in controlling these actions.
The development of reliable gene expression profiling technology is having an increasing impact on our understanding of lung cancer biology. Our study aimed to determine any correlation between the ...phenotypic heterogeneity and genetic diversity of lung cancer. Microarray analysis was performed on a set of 46 tumor samples and 45 paired nontumor samples of nonsmall cell lung cancer (NSCLC) samples to establish gene signatures in primary adenocarcinomas and squamous‐cell carcinomas, determine differentially expressed gene sequences at different stages of the disease and identify sequences with biological significance for tumor progression. After the microarray analysis, the expression level of 92 selected genes was validated by qPCR and the robust Bonferroni test in an independent set of 70 samples composed of 48 tumor samples and 22 nontumor samples. Gene sequences were differentially expressed as a function of tumor type, stage and differentiation grade. High upregulation was observed for KRT15 and PKP1, which may be good markers to distinguish squamous‐cell carcinoma samples. High downregulation was observed for DSG3 in stage IA adenocarcinomas.
Palladium nanoparticles have been immobilized into an amino‐functionalized metal–organic framework (MOF), MIL‐101Cr‐NH2, to form Pd@MIL‐101Cr‐NH2. Four materials with different loadings of palladium ...have been prepared (denoted as 4‐, 8‐, 12‐, and 16 wt %Pd@MIL‐101Cr‐NH2). The effects of catalyst loading and the size and distribution of the Pd nanoparticles on the catalytic performance have been studied. The catalysts were characterized by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier‐transform infrared (FTIR) spectroscopy, powder X‐ray diffraction (PXRD), N2‐sorption isotherms, elemental analysis, and thermogravimetric analysis (TGA). To better characterize the palladium nanoparticles and their distribution in MIL‐101Cr‐NH2, electron tomography was employed to reconstruct the 3D volume of 8 wt %Pd@MIL‐101Cr‐NH2 particles. The pair distribution functions (PDFs) of the samples were extracted from total scattering experiments using high‐energy X‐rays (60 keV). The catalytic activity of the four MOF materials with different loadings of palladium nanoparticles was studied in the Suzuki–Miyaura cross‐coupling reaction. The best catalytic performance was obtained with the MOF that contained 8 wt % palladium nanoparticles. The metallic palladium nanoparticles were homogeneously distributed, with an average size of 2.6 nm. Excellent yields were obtained for a wide scope of substrates under remarkably mild conditions (water, aerobic conditions, room temperature, catalyst loading as low as 0.15 mol %). The material can be recycled at least 10 times without alteration of its catalytic properties.
And the winner is…︁The catalytic activity of Pd nanoparticles immobilized on MIL‐101‐NH2 was studied as a function of the amount of Pd loaded into the metal–organic framework. For the first time, the importance of fine‐tuning this parameter is presented. This study has resulted in an excellent heterogeneous catalyst for Suzuki–Miyaura cross‐coupling reactions in water at room temperature.
Sphingolipids are a class of complex lipids containing a backbone of sphingoid bases, namely the organic aliphatic amino alcohol sphingosine (Sph), that are essential constituents of eukaryotic ...cells. They were first described as major components of cell membrane architecture, but it is now well established that some sphingolipids are bioactive and can regulate key biological functions. These include cell growth and survival, cell differentiation, angiogenesis, autophagy, cell migration, or organogenesis. Furthermore, some bioactive sphingolipids are implicated in pathological processes including inflammation-associated illnesses such as atherosclerosis, rheumatoid arthritis, inflammatory bowel disease (namely Crohn's disease and ulcerative colitis), type II diabetes, obesity, and cancer. A major sphingolipid metabolite is ceramide, which is the core of sphingolipid metabolism and can act as second messenger, especially when it is produced at the plasma membrane of cells. Ceramides promote cell cycle arrest and apoptosis. However, ceramide 1-phosphate (C1P), the product of ceramide kinase (CerK), and Sph 1-phosphate (S1P), which is generated by the action of Sph kinases (SphK), stimulate cell proliferation and inhibit apoptosis. Recently, C1P has been implicated in the spontaneous migration of cells from some types of cancer, and can enhance cell migration/invasion of malignant cells through interaction with a Gi protein-coupled receptor. In addition, CerK and SphK are implicated in inflammatory responses, some of which are associated with cancer progression and metastasis. Hence, targeting these sphingolipid kinases to inhibit C1P or S1P production, or blockade of their receptors might contribute to the development of novel therapeutic strategies to reduce metabolic alterations and disease.
Tandem: Allylic alcohols react with N‐chlorosuccinimide (NCS) in a tandem 1,3‐H shift/CCl bond formation leading to α‐chloroketones and α‐chloroaldehydes. The reactions proceed with complete ...selectivity to give single constitutional isomers of monochlorinated carbonyl compounds. The utility of the transformation is illustrated by the straightforward synthesis of 4,5‐disubstituted 2‐aminothiazoles from allylic alcohols.
Novel signaling aspects of ceramide 1-phosphate Presa, Natalia; Gomez-Larrauri, Ana; Dominguez-Herrera, Asier ...
Biochimica et biophysica acta. Molecular and cell biology of lipids,
April 2020, 2020-Apr, 2020-04-00, 20200401, Letnik:
1865, Številka:
4
Journal Article
Recenzirano
The bioactive sphingolipid ceramide 1-phosphate (C1P) regulates key physiologic cell functions and is implicated in a number of metabolic alterations and pathological processes. Initial studies using ...different types of fibroblasts and monocytes/macrophages revealed that C1P was mitogenic and that it promoted cell survival through inhibition of apoptosis. Subsequent studies implicated C1P in inflammatory responses with a specific role as pro-inflammatory agent. Specifically, C1P potently stimulated cytosolic phospholipase A2 (cPLA2) resulting in elevation of arachidonic acid and pro-inflammatory eicosanoid levels. However, increasing experimental evidence suggests that C1P can also exert anti-inflammatory actions in some cell types and tissues. Specifically, it has been demonstrated that C1P inhibits the release of pro-inflammatory cytokines and blocks activation of the pro-inflammatory transcription factor NF-κB in some cell types. Moreover, C1P was shown to increase the release of anti-inflammatory interleukin-10 in macrophages, and to overcome airway inflammation and reduce lung emphysema in vivo. Noteworthy, C1P stimulated cell migration, an action that is associated with diverse physiological cell functions, as well as with inflammatory responses and tumor dissemination. More recently, ceramide kinase (CerK), the enzyme that produces C1P in mammalian cells, has been shown to be upregulated during differentiation of pre-adipocytes into mature adipocytes, and that exogenous C1P, acting through a putative Gi protein-coupled receptor, negatively regulates adipogenesis. Although the latter actions seem to be contradictory, it is plausible that exogenous C1P may balance the adipogenic effects of intracellularly generated (CerK-derived) C1P in adipose tissue. The present review highlights novel signaling aspects of C1P and its impact in the regulation of cell growth and survival, inflammation and tumor dissemination.
•C1P regulates cell growth and death.•C1P regulates cell migration and invasion of normal and malignant cells.•C1P is a new regulator of adipogenesis.•C1P is implicated in inflammatory responses.
Ceramide 1-phosphate (C1P) is a bioactive sphingolipid that is implicated in the regulation of vital cellular functions and plays key roles in a number of inflammation-associated pathologies. C1P was ...first described as mitogenic for fibroblasts and macrophages and was later found to promote cell survival in different cell types. The mechanisms involved in the mitogenic actions of C1P include activation of MEK/ERK1-2, PI3K/Akt/mTOR, or PKC-α, whereas promotion of cell survival required a substantial reduction of ceramide levels through inhibition of serine palmitoyl transferase or sphingomyelinase activities. C1P and ceramide kinase (CerK), the enzyme responsible for its biosynthesis in mammalian cells, play key roles in tumor promotion and dissemination. CerK-derived C1P can be secreted to the extracellular milieu by different cell types and is also present in extracellular vesicles. In this context, whilst cell proliferation is regulated by intracellularly generated C1P, stimulation of cell migration/invasion requires the intervention of exogenous C1P. Regarding inflammation, C1P was first described as pro-inflammatory in a variety of cell types. However, cigarette smoke- or lipopolysaccharide-induced lung inflammation in mouse or human cells was overcome by pretreatment with natural or synthetic C1P analogs. Both acute and chronic lung inflammation, and the development of lung emphysema were substantially reduced by exogenous C1P applications, pointing to an anti-inflammatory action of C1P in the lungs. The molecular mechanisms involved in the regulation of cell growth, survival and migration with especial emphasis in the control of lung cancer biology are discussed.
•The roles played by C1P in the regulation of cell proliferation, survival and migration in cancer cells are discussed.•Special emphasis is given to the role of C1P in lung cancer growth and dissemination.•The implication of C1P in inflammatory responses is discussed.
Chromosomal architecture is known to influence gene expression, yet its role in controlling cell fate remains poorly understood. Reprogramming of somatic cells into pluripotent stem cells (PSCs) by ...the transcription factors (TFs) OCT4, SOX2, KLF4 and MYC offers an opportunity to address this question but is severely limited by the low proportion of responding cells. We have recently developed a highly efficient reprogramming protocol that synchronously converts somatic into pluripotent stem cells. Here, we used this system to integrate time-resolved changes in genome topology with gene expression, TF binding and chromatin-state dynamics. The results showed that TFs drive topological genome reorganization at multiple architectural levels, often before changes in gene expression. Removal of locus-specific topological barriers can explain why pluripotency genes are activated sequentially, instead of simultaneously, during reprogramming. Together, our results implicate genome topology as an instructive force for implementing transcriptional programs and cell fate in mammals.
Internet of Things environments are comprised of heterogeneous devices that are continuously exchanging information and being accessed ubiquitously through lossy networks. This drives the need of a ...flexible, lightweight and adaptive access control mechanism to cope with the pervasive nature of such global ecosystem, ensuring, at the same time, reliable communications between trusted devices. To fill this gap, this paper proposes a flexible trust-aware access control system for IoT (TACIoT), which provides an end-to-end and reliable security mechanism for IoT devices, based on a lightweight authorization mechanism and a novel trust modelthat has been specially devised for IoT environments. TACIoT extends traditional access control systems by taking into account trust values which are based on reputation, quality of service, security considerations and devices’ social relationships. TACIoT has been implemented and evaluated successfully in a real testbed for constrained and non-constrained IoT devices.
DNA methylation patterns are important for establishing cell, tissue, and organism phenotypes, but little is known about their contribution to natural human variation. To determine their contribution ...to variability, we have generated genome-scale DNA methylation profiles of three human populations (Caucasian-American, African-American, and Han Chinese-American) and examined the differentially methylated CpG sites. The distinctly methylated genes identified suggest an influence of DNA methylation on phenotype differences, such as susceptibility to certain diseases and pathogens, and response to drugs and environmental agents. DNA methylation differences can be partially traced back to genetic variation, suggesting that differentially methylated CpG sites serve as evolutionarily established mediators between the genetic code and phenotypic variability. Notably, one-third of the DNA methylation differences were not associated with any genetic variation, suggesting that variation in population-specific sites takes place at the genetic and epigenetic levels, highlighting the contribution of epigenetic modification to natural human variation.
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