Sphingosine 1-phosphate (S1P) is a bioactive lipid whose levels are tightly regulated by its synthesis and degradation. Intracellularly, S1P is dephosphoryled by the actions of two S1P-specific phosphatases, sphingosine 1-phosphate phosphatase 1 and 2. To identify the physiologic functions of S1P phosphatase 1, we have studied mice with its gene, Sgpp1, deleted. Sgpp1-/- mice appeared normal at birth but during the first week of life, they exhibited stunted growth, suffered desquamation, and most died before weaning. Interestingly, the epidermal permeability barrier developed normally during embryogenesis. Sgpp1 -/- pups and surviving adults exhibited epidermal hyperplasia and abnormal expression of keratinocyte differentiation markers. Keratinocytes isolated from Sgpp1 -/- skin had increased intracellular S1P levels, and expressed a gene expression profile that indicated enhanced differentiation. The results reveal S1P metabolism as a regulator of keratinocyte differentiation and epidermal homeostasis.
Sphingosine-1-phosphate phosphatase 1 regulates keratinocyte differentiation and epidermal homeostasis.
Specimen part
View SamplesThe cleavage of sphingoid base phosphates by sphingosine-1-phosphate (S1P) lyase to produce phosphoethanolamine and a fatty aldehyde is the final degradative step in the sphingolipid metabolic pathway. We have studied mice with an inactive S1P lyase gene and have found that, in addition to the expected increase of sphingoid base phosphates, other sphingolipids (including sphingosine, ceramide, and sphingomyelin) were substantially elevated in the serum and /or liver of these mice. This latter increase is consistent with a reutilization of the sphingosine backbone for sphingolipid synthesis due to its inability to exit the sphingolipid metabolic pathway. Furthermore, the S1P lyase deficiency resulted in changes in the levels of serum and liver lipids not directly within the sphingolipid pathway, including phospholipids, triacyglycerol, diacylglycerol, and cholesterol. Even though lipids in serum and lipid storage were elevated in liver, adiposity was reduced in the S1P lyase-deficient mice. Microarray analysis of lipid metabolism genes in liver showed that the S1P lyase deficiency caused widespread changes in their expression pattern. These results demonstrate that S1P lyase is a key regulator of the levels of multiple sphingolipid substrates and reveal functional links between the sphingolipid metabolic pathway and other lipid metabolic pathways that may be mediated by shared lipid substrates and changes in gene expression programs. The disturbance of lipid homeostasis by altered sphingolipid levels may be relevant to metabolic diseases.
Sphingosine 1-phosphate lyase deficiency disrupts lipid homeostasis in liver.
Specimen part
View SamplesSandhoff disease, one of the GM2 gangliosidoses, is a lysosomal storage disorder characterized by the absence of b-hexosaminidase A and B activity and the concomitant lysosomal accumulation of its substrate, GM2 ganglioside. It features catastrophic neurodegeneration and death in early childhood. How the lysosomal accumulation of ganglioside might affect the early development of the nervous system is not understood. Recently, cerebral organoids derived from induced pluripotent stem (iPS) cells have illuminated early developmental events altered by disease processes. To develop an early neurodevelopmental model of Sandhoff disease, we first generated iPS cells from the fibroblasts of an infantile Sandhoff disease patient, then corrected one of the mutant HEXB alleles in those iPS cells with CRISPR/Cas9 genome-editing technology, thereby creating isogenic controls. Next, we used the parental Sandhoff disease iPS cells and isogenic HEXB-corrected iPS cell clones to generate cerebral organoids that modeled the first trimester of neurodevelopment. The Sandhoff disease organoids but not the HEXB-corrected organoids accumulated GM2 ganglioside, and exhibited increased size and cellular proliferation compared with the HEXB-corrected organoids. Whole-transcriptome analysis demonstrated that development was impaired in the Sandhoff disease organoids, suggesting that alterations in neuronal differentiation may occur during early development in the GM2 gangliosidoses Overall design: Sandhoff disease and corrected cerebral organoids grown for 8 and 10 weeks were analyzed: four samples at each time point, each consisting of 4–6 pooled organoids, for both Sandhoff and corrected. Whole transcriptome from Sandhoff disease and corrected organoids for both time points were generated by deep sequencing on an Illumina HiSeq 2500.
Cerebral organoids derived from Sandhoff disease-induced pluripotent stem cells exhibit impaired neurodifferentiation.
Specimen part, Subject
View SamplesSphingosine-1-phosphate (S1P) is a sphingolipid metabolite that regulates basic cell functions through metabolic and signaling pathways. Intracellular metabolism of S1P is controlled, in part, by two homologous S1P phosphatases, 1 and 2, which are encoded by Sgpp1 and Sgpp2, respectively. S1P phosphatase activity is needed for efficient recycling of sphingosine into the sphingolipid synthesis pathway. S1P phosphatase 1 is important for skin homeostasis, but little is known about the functional role of S1P phosphatase 2. To identify the functions of S1P phosphatase 2 in vivo, we studied mice with the Sgpp2 gene deleted. In contrast to Sgpp1-/- mice, Sgpp2-/- mice had normal skin and were viable into adulthood. Unexpectedly, WT mice expressed Sgpp2 mRNA at high levels in pancreatic islets when compared with other tissues. Sgpp2-/- mice had normal blood insulin levels and pancreatic islet size; however, Sgpp2-/- mice treated with a high-fat diet (HFD) had significantly lower blood insulin levels and smaller pancreatic islets compared with WT mice. The smaller islets in the HFD-treated Sgpp2-/- mice had a significantly lower adaptive -cell proliferation rate in response to the diet compared with HFD-treated WT mice. Importantly, -cells from Sgpp2-/- mice fed a normal diet showed significantly increased expression of proteins characteristic of the endoplasmic reticulum (ER) stress response compared with -cells from WT mice. Our results suggest that Sgpp2 deletion causes -cell ER stress, which is a known cause of -cell dysfunction, and reveal a novel juncture in the sphingolipid recycling pathway that could impact the development of diabetes.
Sphingosine-1-phosphate Phosphatase 2 Regulates Pancreatic Islet β-Cell Endoplasmic Reticulum Stress and Proliferation.
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View SamplesMicroarrays were used to determine relative global gene expression changes in WT and BRCA1-mutation carrier breast epithelium as well as tumors created from WT and BRCA1-mutation carrier breast epithelial cells.
Genetic predisposition directs breast cancer phenotype by dictating progenitor cell fate.
Specimen part, Disease, Disease stage
View SamplesCarcinoma cells can acquire key malignant traits by reprogramming their differentiation state via an epithelial-to-mesenchymal transition (EMT). Cancer cells that undergo EMT become invasive and resist a wide range of therapies including most chemotherapy drugs and radiation. Such cells are also able to efficiently seed primary and metastatic tumors, making them functionally indistinguishable from tumor-initiating or cancer stem-like cells (TICs or CSCs). Therefore, there is significant interest in finding vulnerabilities of cancer cells that have undergone EMT.
Epithelial-to-mesenchymal transition activates PERK-eIF2α and sensitizes cells to endoplasmic reticulum stress.
Cell line, Treatment
View SamplesAcute myeloid leukemia (AML) continues to have the lowest survival rates of all leukemias. Therefore, new therapeutic strategies are urgently needed to improve clinical outcomes for AML patients. Here, we report a novel role for Wilms’ tumor 1-associated protein (WTAP) in pathogenesis of AML. We have performed RNA-Seq in K562 cells with knockdown of WTAP to ascertain which genes it regulates. Overall design: We have 2 replicates of total RNA for K562 cells and 2 replicates with WTAP knocked down
WTAP is a novel oncogenic protein in acute myeloid leukemia.
Subject
View SamplesThe entorhinal cortex of the mouse seems to be sensitive to molecular mechanisms that have been linked to the pathology of Alzheimer's disease. In this microarray study we are interested in comparing the expression profile of the left versus the right EC of the mouse, in order to understand if there is a significant difference in gene expression that might reveal any insights into the differential activation of these areas.
Molecular drivers and cortical spread of lateral entorhinal cortex dysfunction in preclinical Alzheimer's disease.
Age, Specimen part
View SamplesWe report an applicaton of small RNA sequencing using high throughput next generation sequencing to identify the small RNA content of cell lines. By sequencing over 30 million reads we could identify a new class of small RNAs previousy observed with tiling arrays and mapping to promoter regions of coding genes. We also identified a large number of small RNAs corresponding to internal exons of coding genes. By using different enzymatic treatments and immunoprecipitation experiments, we have determined that both the promoter associated small RNAs as well as ones within the body of the genes bear 5'' cap structures. Overall design: Examination of the expression of small RNAs (<200nt).
Post-transcriptional processing generates a diversity of 5'-modified long and short RNAs.
No sample metadata fields
View SamplesWe report that the HF/HS-mediated functional enrichment of genes of immunity and inflammation is driven toward normal by the AOF supplementation Obesity may not constantly associate with metabolic disorders and mortality later in life, raising the challenging concept of healthy obesity. Here, high fat-high sucrose (HF/HS) feeding produces hyperglycaemia and hypercholesterolemia, increases oxidative stress, elevates endotoxemia, expands adipose tissue (with enlarged adipocytes, macrophage infiltration and accumulation of cholesterol and oxysterols), and reduces lifespan of obese mice. Despite persistence of obesity, supplementation with an antioxidant formulation normalizes plasma lipids and endotoxemia, prevents macrophage recruitment in adipose tissue, reduces adipose accumulation of cholesterol and cholesterol oxides, and extends lifespan. The HF/HS-mediated functional enrichment of genes of immunity and inflammation (in particular response to lipopolysaccharides) is driven towards normal by the antioxidant formulation. It is concluded that the limitation of immune cell infiltration in adipose tissue on the long term by an antioxidant formulation can increase lifespan independently of body weight and fat storage. It constitutes the hallmark of a healthy adiposity trait. Overall design: Examination of the expression profile of mice adipose tissues fed either standard (Std), High-fat/high-sucrose (HF/HS) or HF/HS + antioxidant formulation (AOF) for 180 days
Healthy adiposity and extended lifespan in obese mice fed a diet supplemented with a polyphenol-rich plant extract.
Age, Specimen part, Cell line, Subject
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