Increased sensitivity to ionizing radiation has been shown to be due to defects in double-strand break repair and mutations in the proteins that detect DNA damage. However, it is now recognized that the cellular radiation response is complex and that radioresistance/radiosensitivity may also be regulated at different levels in the radiation signal transduction pathway. Here, we describe a direc...

Ceramide as a second messenger is a key regulator in apoptosis and cytotoxicity. Ceramide-metabolizing enzymes are ideal target in cancer chemo-preventive studies. Neutral sphingomyelinase (NSMase), acid ceramidase (ACDase) and glucosyl ceramide synthase (GCS) are the main enzymes in ceramide metabolism. Silymarin flavonolignans are potent apoptosis inducers and silibinin is the most active com...

Phosphoinositide-specific phospholipase C (PLC) is a central effector for many biological responses regulated by G-protein-coupled receptors including Drosophila phototransduction where light sensitive channels are activated downstream of NORPA, a PLCbeta homolog. Here we show that the sphingolipid biosynthetic enzyme, ceramide kinase, is a novel regulator of PLC signaling and photoreceptor hom...

OBJECTIVES To examine the effects of ceramide, which is a lipid second messenger of cell surface receptors, including tumour necrosis factor alpha (TNF alpha), interleukin 1 (IL1), and Fas receptors, on rheumatoid arthritis (RA) synovial cells. METHODS Synovial cells from RA patients and normal skin fibroblasts were cultured with cell permeable ceramide (C2-ceramide). Apoptosis was assessed b...

Background: Skin is the largest organ that functions as a physical barrier. Stable skin pH can maximize its function. Ceramide and shea butter cream have components maintain in stratum corneum. Purpose: The aim to compare ceramide effects on pH. Methods: experimental analytic study was performed 30 respondents. measurement done before applying creams days after cream. applied right volar left v...

The cytotoxic effects of several chemotherapeutic drugs have been linked to elevated de novo ceramide biosynthesis. However, the relationship between the intracellular site(s) of ceramide accumulation and cytotoxicity is poorly understood. Here we examined the relationship between the site of ceramide deposition and inhibition of protein translation and induction of apoptosis by the antitumor/a...

The physiological role of ceramide formation in response to cell stimulation remains controversial. Here, we emphasize that ceramide is not a priori an apoptotic signalling molecule. Recent work points out that the conversion of sphingomyelin into ceramide can play a membrane structural (physical) role, with consequences for membrane microdomain function, membrane vesiculation, fusion/fission a...

The sphingomyelin (SM) pathway is a ubiquitous, evolutionarily conserved signalling system analogous to conventional systems such as the cAMP and phosphoinositide pathways. Ceramide, which serves as second messenger in this pathway, is generated from SM by the action of a neutral or acidic SMase, or by de novo synthesis co-ordinated through the enzyme ceramide synthase. A number of direct targe...

We previously reported that ceramide, the immediate product of sphingomyelin hydrolysis, increases in response to interleukin (IL)-1 beta and plays a role in modulating IL-1 beta-mediated prostaglandin E2 production and cyclooxygenase gene expression in human fibroblasts (Ballou, L. R., C. P. Chao, M. A. Holness, S. C. Barker, and R. Raghow. 1992. J. Biol. Chem. 267:20044-20050). Here we descri...

A major lipid-signaling pathway in mammalian cells implicates the generation of ceramide from the ubiquitous sphingolipid sphingomyelin (SM). Hydrolysis of SM by a sphingomyelinase present in acidic compartments has been reported to mediate, via the production of ceramide, the apoptotic cell death triggered by stress-inducing agents. In the present study, we investigated whether the ceramide fo...