Project description:Although, ectopic ceramide accumulation impairs nutrient sensing in adipocytes, leading to deterioration in energy and glucose homeostasis, the underlying mechanisms remain poorly defined. Using, comparative screen to identify ceramide regulated effector molecule in adipose tissue, we found fibroblast growth factor 13 (FGF13) as one of the critical ceramide-effector molecules that impair nutrient sensing in adipocytes. FGF13 is a cytosolic, non-secreted FGF belonging to a non-canonical FGF family member that comprises of FGF11-FGF14 and do not activate FGF receptors. FGF13 has been implicated in numerous physiological process such as development, cardiac arrythmias, neurological disease and cancer. We demonstrate that FGF13 expression is highly induced in adipose tissue in response to a high fat diet, and its expression is negated by pharmacological and genetic interventions that inhibit ceramide biosynthesis. Inhibition of FGF13 in adipocytes (white, brown and beige), alters adipocyte morphology, prevents the development of obesity, improves glucose homeostasis, insulin sensitivity and resolves hepatic steatosis
Project description:The bioactive sphingolipid ceramide, generated by ceramide synthase, is an adaptive stress effector induced in response to various stress stimuli such as aging. In fact, ceramide synthase (CerS) was first discovered in yeast as a longevity assurance gene (LAG1), as the reduced ceramide generation consequent to LAG1 deletion increased longevity. There are six homologues of mammalian LAG1/ceramide synthases (CerS1-6) that generate ceramides with different fatty acid chain lengths with distinct functions and hydrophobicity. Ceramide can be metabolized by sphingosine kinase 1 or 2 for the generation of pro-survival sphingosine 1-phosphate (S1P), which enhances immune cell egress to the blood stream, activating immune function. Ceramide is known to induce mitophagy and cell death. Here we investigated the role of this sphingolipid pathway in immune function, specifically T cell functions, via high throughput expression profiling.
Project description:Analysis of Neuroblastoma SH-SY5Y cell line treated with C2 ceramide, or combination of C2 ceramide and PJ34. Samples were collected in three time points: 3 hours, 6 hours and 24 hours. Results provide insight into the mechanism of cramide induced cell death and role of poly (ADP-ribose) polymerase in these proces.
Project description:Hematopoietic stem and progenitor cells (HSPCs) rely upon cellular crosstalk, including extracellular vesicles (EVs) for lifelong niche occupancy and cellular function. Vesicle secretion is tightly linked to intracellular homeostasis; however, these mechanisms are poorly understood in HSPCs, particularly at the single-cell level. In this study, we target ceramide-dependent EV secretion by pharmacologic blockade in ex vivo expanded HSPCs. We use these cells to investigate single-cell resolution of short-term and delayed transcriptional changes induced by ceramide-EV inhibition.
Project description:We have used human umbilical vein endothelial cell line (HUVEC) as a model to investigate the effect of ultrasound (US) activated micro-bubbles on sensitizing the tumour response to radiation and to check the implication of this approach on gene expression. The use of micro-bubbles in cancer therapy is a novel approach that is being recently investigated, and patterns of gene expressions were not yet characterized. Gene analysis has identified about 19,264 genes; where, 239 – 517 genes have shown more than two folds up-regulation in response to the different treatments. This included a number of genes that are known to be involved in apoptosis and ceramide-induced apoptosis pathways, such as Sphingomyelin phosphodiesterase 2, neutral sphingomyelinase (SMPD2), sphingomyelin phosphodiesterase 1, acid lysosomal (ASM; SMPD1), UDP-galactose ceramide galactosyltransferase (UGT8), cytochrome c oxidase (COX6B1), Caspase-9 and mitogen-activated protein kinase kinase 1 (MAP2K1). To verify these results, we have performed Real time RT-PCR, which indicated an up-regulation that ranged from 2 to 200 folds, specifically in the combined treatment of US, 3.3% micro-bubbles and 8 Gy. The observed higher levels of expression of UGT8, SMPD2 and Caspase 9-alpha when compared to the control or to radiation only indicated the involvement of ceramide, which possibly induces apoptosis . These results support the hypothesis that micro-bubbles play a role in increasing sensitization to radiation, and can prove to be an effective cancer therapeutic approach. Gene analysis has identified about 19,264 genes; where, 239 – 517 genes have shown more than two folds up-regulation in response to the different treatments. This included a number of genes that are known to be involved in apoptosis and ceramide-induced apoptosis pathways, such as Sphingomyelin phosphodiesterase 2, neutral sphingomyelinase (SMPD2), sphingomyelin phosphodiesterase 1, acid lysosomal (ASM; SMPD1), UDP-galactose ceramide galactosyltransferase (UGT8), cytochrome c oxidase (COX6B1), Caspase-9 and mitogen-activated protein kinase kinase 1 (MAP2K1). To verify these results, we have performed Real time RT-PCR, which indicated an up-regulation that ranged from 2 to 200 folds, specifically in the combined treatment of US, 3.3% micro-bubbles and 8 Gy. The observed higher levels of expression of UGT8, SMPD2 and Caspase 9-alpha when compared to the control or to radiation only indicated the involvement of ceramide, which possibly induces apoptosis . These results support the hypothesis that micro-bubbles play a role in increasing sensitization to radiation, and can prove to be an effective cancer therapeutic approach.
Project description:Ceramide is an important lipid in skin barrier function. Psoriasis is a chronic inflammatory skin disease, and the skin barrier function has disturbed. Furthermore, the balance of each ceramide species in stratum corneum is disrupted in psoriatic skin. However, it involved remains unclear what detailed mechanism ceramide species changed in psoriatic skin lesion. We comprehensively investigated lipid metabolism including ceramide in skin of psoriasis patients by DNA microarray analysis. The expression level of PNPLA1 gene involved in acylceramide synthesis which is epidermis-specific ceramide species essential for skin barrier function was decreased in psoriatic skin. In contrast, the expression level of lipid metabolism-related enzymes gene including ceramide were increased in psoriatic skin. Consequently, the acylceramide synthesis was decreased in skin of psoriasis patients, suggesting that increased biosynthesis of other sphingolipids to supplement the function of acylceramide may cause the pathology of psoriasis.
Project description:In early embryogenesis, the primitive streak (PrS) generates the mesendoderm and is essential for organogenesis. However, because the PrS is a minute and transient tissue, elucidating the mechanism of its formation had been challenging. We had identified ceramide metabolism to regulate PrS formation. We investigated how C2 ceramide, a cell-permeable form of ceramide, affects gene expression for PrS formation.