Studies fronn the laboratory ofthe PI have focused on elucidating the components, mechanisms, and roles of bioactive sphingolipids, especially ceramide with its emerging roles In regulating cell growth, differentiation, senescence, and inflammation. However, the study of these pathways has been complicated by their multiplicity, metabolic interactions, sub cellular compartmentalization, and lack of molecular tools. These considerations led us to the overall hypothesis that the specific cellular functions of ceramide are dictated by the sub cellular site of ceramide generation which in turn depends on which of the enzymes of ceramide metabolism regulates its site-specific formation. In this proposal we will focus on the neutral sphingomyelinase (SMase) pathway focusing on an extended family of enzymes identified by the PI and others. Specifically, we will address the following alms: 1) To define cellular mechanisms of regulation of nSMases. We will investigate the specific hypothesis that defined signaling pathways lead to the activation/regulation of n-SMase2 in response to TNF and retinoic acid. We will also study the mechanisms by which oxidative stress regulates the activation of ma-nSMase, which we recently identified as a novel mitochondrial sphingomyelinase. 2) To determine molecular and biochemical mechanisms of activation of nSMases. We will determine the mechanisms by which nSMase2 and ma-nSMase interact with phosphatidylserine and cardiolipin, respectively, as activating lipids, and we will determine the mechanisms of phosphorylation and palmitoylation and their roles in activation and translocation of nSMases. 3) To determine the role of nSMases in generating a specific 'pool' of ceramide with specific downstream functions. We will test the specific hypothesis that nSMase2 and ma-nSMase act on a distinct pool of sphingomyelin that resides In the inner leaflet ofthe plasma membrane and in the outer leaflet ofthe mitochondrion, respectively, leading to the corresponding subset of ceramide, with its own specific functions. Taken together, these results should provide a foundation for the study of molecularly-distinct sphingolipid-mediated pathways of cell regulation. Moreover, molecular studies on nSMase2 and ma-nSMsae would also impact our understanding of the mechanisms of an emerging and novel family of phospholipid phosphodiesterases. These pathways are of direct significance to the biology of stress responses and specifically to cancer biology and inflammation.

Public Health Relevance

The PI has identified a novel family of enzymes that regulate the formation of important lipid (fat) molecules that function in transmitting and modulating stress signals to cells. Understanding these pathways is important for our understanding of lipid-mediated biology, membrane and vesicular trafficking, human leukemia, osteogenesis imperfecta (a bone disease that should shed light on osteoporosis), and cancer therapeutics.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
4R37GM043825-23
Application #
8109695
Study Section
Special Emphasis Panel (NSS)
Program Officer
Chin, Jean
Project Start
1997-07-01
Project End
2017-05-31
Budget Start
2012-06-01
Budget End
2013-05-31
Support Year
23
Fiscal Year
2012
Total Cost
$455,300
Indirect Cost
$165,300
Name
State University New York Stony Brook
Department
None
Type
Schools of Medicine
DUNS #
804878247
City
Stony Brook
State
NY
Country
United States
Zip Code
11794
Shamseddine, Achraf A; Airola, Michael V; Hannun, Yusuf A (2015) Roles and regulation of neutral sphingomyelinase-2 in cellular and pathological processes. Adv Biol Regul 57:24-41
Zhao, Lihong; Spassieva, Stefka; Gable, Kenneth et al. (2015) Elevation of 20-carbon long chain bases due to a mutation in serine palmitoyltransferase small subunit b results in neurodegeneration. Proc Natl Acad Sci U S A 112:12962-7
Airola, Michael V; Allen, William J; Pulkoski-Gross, Michael J et al. (2015) Structural Basis for Ceramide Recognition and Hydrolysis by Human Neutral Ceramidase. Structure 23:1482-91
Wu, Bill X; Fan, Jie; Boyer, Nicholas P et al. (2015) Lack of Acid Sphingomyelinase Induces Age-Related Retinal Degeneration. PLoS One 10:e0133032
Shamseddine, A A; Clarke, C J; Carroll, B et al. (2015) P53-dependent upregulation of neutral sphingomyelinase-2: role in doxorubicin-induced growth arrest. Cell Death Dis 6:e1947
Lu, Zhongyang; Li, Yanchun; Jin, Junfei et al. (2015) GPR40/FFA1 and neutral sphingomyelinase are involved in palmitate-boosted inflammatory response of microvascular endothelial cells to LPS. Atherosclerosis 240:163-73
Rajagopalan, Vinodh; Canals, Daniel; Luberto, Chiara et al. (2015) Critical determinants of mitochondria-associated neutral sphingomyelinase (MA-nSMase) for mitochondrial localization. Biochim Biophys Acta 1850:628-39
Spincemaille, Pieter; Chandhok, Gursimran; Newcomb, Benjamin et al. (2014) The plant decapeptide OSIP108 prevents copper-induced apoptosis in yeast and human cells. Biochim Biophys Acta 1843:1207-15
Jones, E Ellen; Dworski, Shaalee; Canals, Daniel et al. (2014) On-tissue localization of ceramides and other sphingolipids by MALDI mass spectrometry imaging. Anal Chem 86:8303-11
Wei, Jianwen; Ferron, Mathieu; Clarke, Christopher J et al. (2014) Bone-specific insulin resistance disrupts whole-body glucose homeostasis via decreased osteocalcin activation. J Clin Invest 124:1-13

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