Role of sphingolipids signaling in pathogenesis of pulmonary fibrosis / 中国药理学与毒理学杂志

Pulmonary fibrosis is a group of chronic lung diseases caused by various factors and characterized by chronic inflammations,lung tissue structure damage,increase of pulmonary interstitial collagen and massive deposition of extracellular matrix (ECM). Because of its complicated etiology, there is no effective treatment currently. Recent studies showed that the activation of sphingolipids signaling and pulmonary fibrosis were closely related. This paper describes the composition and function of sphingolipids signaling pathway and its effect on fibrosis in order to provide new ideas about further study of the pathogenesis of pulmonary fibrosis and methods of prevention.

Dietary effect of red ginseng extracts mixed with torilis fructus and corni fructus on the epidermal levels of ceramides and ceramide related enzyme proteins in uv-induced hairless mice

UV-irradiation is a major factor of photo-aged skin, by which pigmentation, wrinkles and laxity are increased. In addition, the epidermal barrier is disrupted, ultimately causing dryness in photo-aged skin. As an effort to search dietary sources for improving the dryness of UV irradiated skin, the dietary effect of red ginseng based functional foods on the epidermal level of ceramides, a major lipid maintaining epidermal barrier, was determined in this study. Albino hairless mice were fed either a control diet [group UV (UV-irradiated control)] or diets with 0.5% (group M0.5) or 1% (group M1.0) of red ginseng extracts mixed with Torilis fructus and Corni fructus (66.7% red ginseng) in parallel with UV irradiation for 5 wks. A normal control group (group C) was fed a control diet without UV irradiation for 5 wks. The epidermal level of ceramides in group UV was significantly lower than that in group C, in which ceramidase, an enzyme involved in ceramide degradation, was highly expressed. In group M0.5, the epidermal level of ceramide was significantly increased to the level even higher than in group C. In addition, protein expression of serine palmitoyl transferase (SPT), a key enzyme involved in de novo ceramide synthesis, was increased in group M0.5. However the epidermal levels of ceramides as well as of ceramidase protein expression in group M1.0 did not differ from those in group UV. In conclusion, we demonstrate that dietary supplementation of red-ginseng extracts mixed with Torilis fructus and Corni fructus at a level of 0.5% level in diet increased the epidermal level of ceramides coupled with the elevated expression of SPT protein.

A Study on Altered Expression of Serine Palmitoyltransferase and Ceramidase in Psoriatic Skin Lesion

Ceramides are the main lipid component maintaining the lamellae structure of stratum corneum, as well as lipid second messengers for the regulation of cellular proliferation and/or apoptosis. In our previous study, psoriatic skin lesions showed marked decreased levels of ceramides and signaling molecules, specially protein kinase C-alpha (PKC-alpha) and c-jun N-terminal kinase (JNK) in proportion to the psoriasis area and severity index (PASI) scores, which suggested that the depletion of ceramide is responsible for epidermal hyperproliferation of psoriasis via downregulation of proapoptotic signal cascade such as PKC-alpha and JNK. In this study, we investigated the protein expression of serine palmitoyltransferase (SPT) and ceramidase, two major ceramide metabolizing enzymes, in both psoriatic epidermis and non-lesional epidermis. The expression of SPT, the ceramide generating enzyme in the de novo synthesis in psoriatic epidermis, was significantly less than that of the non-lesional epidermis, which was inversely correlated with PASI score. However, the expression of ceramidase, the degradative enzyme of ceramides, showed no significant difference between the lesional epidermis and the non-lesional epidermis of psoriatic patients. This might suggest that decreased expression of SPT protein is one of the important causative factors for decreased ceramide levels in psoriasis.

The role of ceramidase in murine ovarian granulosa cell death / 대한산부인과학회잡지

OBJECTIVE: One of the models we study is the ovarian granulosa cell (GC), a somatic cell lineage that is critically important for maintenance of the female germ line and many endocrine functions of the ovaries. The objective of this study is to clarify the significance of ceramide and the role of ceramide metabolism in dictating the fate of cells exposed to stress. METHODS: We first treated GC with a C8-ceramide analog or an amine derivative of ceramide that cannot be metabolized by ceramidase (C8-ceramine). Northern blot analysis was performed to evaluate mRNA of acid ceramidease expression regualted by gonadotropin and in situ hybridization was done to identify the mRNA expression of acid ceramidase in ovaries. RESULTS: After 6 hours, C8-ceramide (50 micro M) triggered apoptosis in only 28 +/- 6% of the cells, whereas C8-ceramine (50 micro M) induced apoptosis in all cells (LD50=1 micro M). These data suggested that ceramidase activity is a critical determinant of GC survival. In situ hybridization showed that mRNA of acid ceramidase was highly expressed in GC in growing follicle. mRNA of acid ceramidase was expressed abundantly in granulosa cells and ovaries and its expression was significantly increased by gonadotropin in granulosa cells in in situ hybridization. Forty two hour after gonadotropin treatment, mRNA expression of acid ceramidase in granulosa cells was two fold increased cells comparing with no treatment control in northern blot analysis (P<0.05). In copora lutea, elevated mRNA expression of acid ceramidase was decreased. CONCLUSION: We concluded that GC possess inherently high levels of ceramidase activity, and that ceramidase has important for metabolizing ceramind to maintain GC survival in the ovary.

Mitochondrial ceramidase overexpression up-regulates Bcl-2 protein level in K562 cells probably through its metabolic product sphingosine-1-phosphate / 中国病理生理杂志

AIM: To investigate the role of mitochondrial ceramidase in mitochondrial functions, especially in the regulation of apoptosis. METHODS: pCDNA3.1/His-MtCDase plasmid, containing mitochondrial ceramidase cDNA sequence, was transfected into K562 cells by liposome, and G418 was used to screen the positive clones. A stable transfected K562 cell line was established and defined as ‘K562TC’. The differences between K562 and K562TC cells in serum withdrawal resistance and Bcl-2 protein expression were evaluated by annexin V/PI test, flow cytometry and Western blotting, respectively. RESULTS: K562TC cells with elevated Bcl-2 protein expression level identified by FCM or Western blotting showed stronger resistance to apoptosis induced by serum withdrawal than their parental cells. Inhibition of mitochondrial ceramidase expression in K562TC cells by its specific antisense oligodeoxynucleotide was correlated with a decrease in Bcl-2 protein level. N, N'-dimethylsphingosine (DMS), a sphingosine kinase inhibitor, depleted intracellular sphingosine-1-phosphate (SPP) production, also abrogated Bcl-2 protein expression in K562TC cells, while exogenous sphingosine-1-phosphate up-regulated Bcl-2 protein level in K562 cells. CONCLUSION: Mitochondrial ceramidase overexpression in K562 cells leads to markedly elevated level of Bcl-2 protein and results in more resistance to serum withdrawal. This effect is initiated not by sphingosine, the direct metabolite of mitochondrial ceramidase, but via sphingosine-1-phosphate, its phosphorylated form, indicating that mitochondrial ceramidase, through its sphingoid metabolite sphingosine-1-phosphate, up-regulates Bcl-2 protein expression in K562 cells.