FTY720 protects cardiac microvessels of diabetes: a critical role of S1P1/3 in diabetic heart disease.
BACKGROUND
Diabetes is associated with an increased risk of cardiac microvascular disease. The mechanisms by which this damage occurs are unknown. However, research suggests that signaling through the sphingosine-1-phosphates receptor 1 and 3 (S1P1/3) by FTY720, a sphiongolipid drug that is structually similar to SIP, may play a role in the treatment on cardiac microvascular dysfunction in diabetes. We hypothesized that FTY720 might exert the cardioprotective effects of S1P1 and S1P3 viaprotein kinase C-beta (PKCβ II) signaling pathway.


RESULTS
Transthoracic echocardiography was performed to detect the change of cardiac function. Scanning and transmission electron microscope with lanthanum tracer were used to determine microvascular ultrastructure and permeability in vivo. Apoptosis was detected by TUNEL and CD31 dual labeling in paraffin-embedded sections. Laser capture miscrodissection was used to assess cardiac micovascular endothelial cells (CMECs) in vivo. RT-PCR and Western blot analysis were used to determine the mRNA levels and protein expression of S1P1, S1P3, and PKCβ II. In the diabetic rats vs. controls, cardiac capillaries showed significantly higher density; CD31 positive endothelial cells were significantly reduced; the apoptosis index of cardiac endothlial cells was significantly higher. And FTY720 could increase the expressional level of S1P1 and boost S1P3 trasnslocation from membrane to nuclear, then ameliorate cardiac microvascular barrier impairment and pathologic angiogenesis induced by diabetes. In addition, overexpression of PKCβ II significantly decreased the protective effect of FTY720.


CONCLUSIONS
Our study represents that the deregulation of S1P1 and S1P3 is an important signalresponsible for cardiac microvascular dysfunction in diabetes. FTY720 might be competent to serve as a potential therapeutic approach for diabetic heart disease through ameliorating cardiac microvascular barrier impairment and pathologic angiogenesis, which might be partly dependent on PKCβII-mediated signaling pathway.
Department of Cardiology, Xijing Hospital, The Fourth Military Medical University, Xi'an City, Shaanxi Province, China.
Zhiyong
Z
Yin
Linni
L
Fan
Liping
L
Wei
Haokao
H
Gao
Rongqing
R
Zhang
Ling
L
Tao
Feng
F
Cao
Haichang
H
Wang
D017209:Apoptosis; D001483:Base Sequence; D015153:Blotting, Western; D003331:Coronary Vessels / Q000187:drug effects*; D017931:DNA Primers; D048909:Diabetes Complications / Q000517:prevention & control*; D000068876:Fingolimod Hydrochloride; D006331:Heart Diseases / Q000150:complications / Q000517:prevention & control*; D006801:Humans; D020287:In Situ Nick-End Labeling; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D055806:Microvessels / Q000187:drug effects*; D009389:Neovascularization, Pathologic; D011409:Propylene Glycols / Q000494:pharmacology*; D049349:Receptors, Lysosphingolipid; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology
D017931:DNA Primers; D011409:Propylene Glycols; D049349:Receptors, Lysosphingolipid; D000068876:Fingolimod Hydrochloride; D013110:Sphingosine