Objective To study the effect of 20-HETE on apoptosis in cultured neonatal rat cardiomyo-cytes and investigate its mechanism. Methods Neonatal rat cardiomyocytes were cultured in vitro.CCK-8 method was used to detect the cell activity and TUNEL assay was performed to analyze the cell apoptosis. Flou-3/AM la-belled assay was applied to measure the concentration of intracellular calcium([Ca2+]i). Western blot was per-formed to measure the expressions of RyR2,SERCA2a,CaMKII and phospho-CaMKII. Results Treatment with 20-HETE reduced the activity of cardiomyocytes and induced cell apoptosis obviously,while KN-93,an inhibitor of CaMKII,blocked the effects of 20-HETE. Treatment with 20-HETE significantly increased cardiomyocytes [Ca2+]i,up-regulated the expression of RyR2,and down-regulated the expression of SERCA2a,which could be blocked by KN-93. 20-HETE also increased the expressions of CaMKII and phospho-CaMKII in cardiomyocytes, indicating 20-HETE played a role in activating the CaMKII signaling pathway. Conclusions 20-HETE leads to altered functions of cardiac sarcoplasmic reticulum calcium-transport protein RyR2 and SERCA2a via activating the CaMKII signaling pathway,which causes calcium overload and induces apoptosis in neonatal rat cardiomyocytes.

Precise orchestration of cell fate determination underlies the success of scaffold-based skeletal regeneration.Despite extensive studies on mineralized parenchymal tissue rebuilding,regenerating and maintaining undifferentiated mesenchyme within calvarial bone remain very challenging with limited advances yet.Current knowledge has evidenced the indispensability of rebuilding suture mesenchymal stem cell niches to avoid severe brain or even systematic damage.But to date,the absence of promising therapeutic biomaterials/scaffolds remains.The reason lies in the shortage of fundamental knowledge and methodological evidence to understand the cellular fate regulations of scaffolds.To address these issues,in this study,we systematically investigated the cellular fate determinations and transcriptomic mechanisms by distinct types of commonly used calvarial scaffolds.Our data elucidated the natural processes without scaffold transplantation and demonstrated how different scaffolds altered in vivo cellular responses.A feasible scaffold,polylactic acid electrospinning membrane(PLA),was next identified to precisely control mesenchymal ingrowth and self-renewal to rebuild non-osteogenic suture-like tissue at the defect center,meanwhile supporting proper osteointegration with defect bony edges.Especially,transcriptome analysis and cellular mechanisms underlying the well-orchestrated cell fate determination of PLA were deciphered.This study for the first time cellularly decoded the fate regulations of scaffolds in suture-bony composite defect healing,offering clinicians potential choices for regenerating such complicated injuries.