sphingosine-kinase and Cicatrix

Sphingolipids have recently emerged as a biomarker of recurrence and mortality after myocardial infarction (MI). The increased ceramide levels in mammalian heart tissues during acute MI, as demonstrated by several groups, is associated with higher cell death rates in the left ventricle and deteriorated cardiac function. Ceramidase, the only enzyme known to hydrolyze proapoptotic ceramide, generates sphingosine, which is then phosphorylated by sphingosine kinase to produce the prosurvival molecule sphingosine-1-phosphate. We hypothesized that Acid Ceramidase (AC) overexpression would counteract the negative effects of elevated ceramide and promote cell survival, thereby providing cardioprotection after MI.. We performed transcriptomic, sphingolipid, and protein analyses to evaluate sphingolipid metabolism and signaling post-MI. We investigated the effect of altering ceramide metabolism through a loss (chemical inhibitors) or gain (modified mRNA [modRNA]) of AC function post hypoxia or MI.. We found that several genes involved in de novo ceramide synthesis were upregulated and that ceramide (C16, C20, C20:1, and C24) levels had significantly increased 24 hours after MI. AC inhibition after hypoxia or MI resulted in reduced AC activity and increased cell death. By contrast, enhancing AC activity via AC modRNA treatment increased cell survival after hypoxia or MI. AC modRNA-treated mice had significantly better heart function, longer survival, and smaller scar size than control mice 28 days post-MI. We attributed the improvement in heart function post-MI after AC modRNA delivery to decreased ceramide levels, lower cell death rates, and changes in the composition of the immune cell population in the left ventricle manifested by lowered abundance of proinflammatory detrimental neutrophils.. Our findings suggest that transiently altering sphingolipid metabolism through AC overexpression is sufficient and necessary to induce cardioprotection post-MI, thereby highlighting the therapeutic potential of AC modRNA in ischemic heart disease.

Topics: Acid Ceramidase; Animals; Animals, Newborn; Apoptosis; Ceramides; Cicatrix; Embryoid Bodies; Enzyme Induction; Female; Genetic Therapy; Humans; Hypoxia; Induced Pluripotent Stem Cells; Inflammation; Male; Mice; Myocardial Infarction; Phosphorylation; Phosphotransferases (Alcohol Group Acceptor); Rats; Rats, Sprague-Dawley; Recombinant Proteins; RNA, Messenger; Sphingolipids; Transfection; Up-Regulation

Wound healing starts with the recruitment of inflammatory cells that secrete wound-related factors. This step is followed by fibroblast activation and tissue construction. Sphingosine-1-phosphate (S1P) is a lipid mediator that promotes angiogenesis, cell proliferation, and attracts immune cells. We investigated the roles of S1P in skin wound healing by altering the expression of its biogenic enzyme, sphingosine kinase-1 (SphK1). The murine excisional wound splinting model was used. Sphingosine kinase-1 (SphK1) was highly expressed in murine wounds and that SphK1

Topics: Animals; Biomarkers; Cell Proliferation; Cicatrix; Disease Models, Animal; Gene Expression; Granuloma; Inflammation; Lysophospholipids; Mice; Mice, Knockout; Neovascularization, Physiologic; Phosphotransferases (Alcohol Group Acceptor); Skin; Sphingosine; Sphingosine-1-Phosphate Receptors; Wound Healing

To study the inhibitory effect of Hepatocyte growth factor (HGF) on the responsive hyperplasia of damaged astrocytes in vitro. We prepared damaged model of astrocytes to simulate the responsive hyperplasia of damaged astrocytes in vivo by culturing astrocytes in vitro; After the first day of Ad-HGF transfection, astrocytes were scratched, then after the first, the third, and the fifth day of scratch, we detect the expression amount of astrocytes specific glial fibrillary acidic protein (GFAP) and the ratio of S-phase cells with flow cytometry, both of which can reflect the proliferation status of damaged astrocytes; After HGF was added in scratched astrocytes, the activity of SPK and MAPK (P42/44) were detected by autoradiography and immunoblotting test; After adding different concentrations of HGF protein in astrocytes cultured in different serum concentrations and adding diverse concentrations of HGF protein, SPK and SPK inhibitor DMS in scratched astrocytes, we detect cell proliferation with 3H-TDR incorporation. The first day after Ad-HGF transfected astrocytes were scratched, the amount of GFAP secreted by astrocytes were decreased significantly (P < 0.05), and the cells in S phase were declined obviously. HGF has bidirectional regulation on SPK of scratched astrocytes: increases the SPK activity when HGF in low dose, while inhibits when in high dose. In addition, DMS can block the signal passage; HGF had no effects on MAPK (P42/44) of damaged astrocytes cells. In conclusion, after the transfection of Ad-HGF, it can inhibit the responsive hyperplasia of damaged astrocytes by the means of blocking SPK passage.

Topics: Adenoviridae; Animals; Astrocytes; Cell Proliferation; Cell Separation; Cells, Cultured; Cicatrix; Green Fluorescent Proteins; Hepatocyte Growth Factor; Humans; Models, Biological; Phosphotransferases (Alcohol Group Acceptor); Protein Kinase Inhibitors; Rats; Rats, Wistar; Signal Transduction; Subcellular Fractions; Transfection