Sphingolipid metabolism and its role in the skeletal tissues
CELLULAR AND MOLECULAR LIFE SCIENCES
Authors: Khavandgar, Zohreh; Murshed, Monzur
Abstract
The regulators affecting skeletal tissue formation and its maintenance include a wide array of molecules with very diverse functions. More recently, sphingolipids have been added to this growing list of regulatory molecules in the skeletal tissues. Sphingolipids are integral parts of various lipid membranes present in the cells and organelles. For a long time, these macromolecules were considered as inert structural elements. This view, however, has radically changed in recent years as sphingolipids are now recognized as important second messengers for signal-transduction pathways that affect cell growth, differentiation, stress responses and programmed death. In the current review, we discuss the available data showing the roles of various sphingolipids in three different skeletal cell types-chondrocytes in cartilage and osteoblasts and osteoclasts in bone. We provide an overview of the biology of sphingomyelin phosphodiesterase 3 (SMPD3), an important regulator of sphingolipid metabolism in the skeleton. SMPD3 is localized in the plasma membrane and has been shown to cleave sphingomyelin to generate ceramide, a bioactive lipid second messenger, and phosphocholine, an essential nutrient. SMPD3 deficiency in mice impairs the mineralization in both cartilage and bone extracellular matrices leading to severe skeletal deformities. A detailed understanding of SMPD3 function may provide a novel insight on the role of sphingolipids in the skeletal tissues.
KONDO EFFECT IN THE SMPD3BX SYSTEM
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
Authors: KASAYA, M; LIU, B; LI, JL; SATA, N; KASUYA, T
Abstract
Addition of boron to SmPd3 seems to shift the E(F) towards the Sm2+ level and causes the Kondo effect in the SmPd3B(x) system. In the course of this experiment, it is also found that the sample of LaPd3 prepared by using an arc furnace shows a long-period superstructure, but the single crystal of LaPd3 made in the sealed Mo crucible by the Bridgman method only have the AuCu3-type structure.