The Regulation Mechanism Of MiR-335 And MiR-674-3p In The RVLM On Stress-induced Hypertension

Hypertension continue to be the chief causes to human health,which pathogenesis is complex and one of the leading causes of coronary heart disease,stroke,kidney failure and other complications.As one of the important factors causing hypertension,stress has attracted increasing attention.With the increase of social pressure,the stressinduced hypertension(SIH)caused by long-term stress seriously damages public health.The rostral ventrolateral medulla(RVLM)is known as the vasomotor center that plays a crucial role in mediating the development of stress-induced hypertension(SIH).Micro RNAs(mi RNAs)are involved in many different biological processes and diseases.However,studies that evaluated the roles of mi RNAs in the RVLM during SIH are not involved.In this study,we performed mi RNA-seq sequencing in the RVLM of SIH rats and Control rats to explore the genome-wide mi RNA profiles in RVLM in a SIH rat model established using administer electric foot-shocks and noises.The function of mi RNAs in blood pressure regulation was determined in vivo via the intra-RVLM microinjection of the agomir or antagomir.In addition,the mechanism of its target genes involved in the occurrence of SIH was explored by inhibiting the expression of mi R-335 in vivo and overexpressing mi R-335 in vitro.Finally,the underlying mechanisms of mi RNAs on SIH were investigated through in vitro and in vivo experiments,like gain-of-function.We discovered 786 mi RNA transcripts among which four were differentially expressed by mi RNA-seq sequencing.The overexpression of mi R-335 and mi R-674-3p in RVLM dramatically increased the heart rate(HR),arterial blood pressure(ABP),systolic blood pressure(SBP),diastolic blood pressure(DBP),and mean arterial pressure(MAP)levels of normotensive rats,whereas the knockdown of mi R-335 and mi R-674-3p in RVLM markedly reduced the HR,ABP,SBP,DBP,and MAP levels of SIH rats.Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)annotation revealed that mi R-335 and mi R-674-3p participated in regulating the development of SIH from different aspects,like apoptosis-multiple species,neuron apoptotic process and MAPK signaling pathway.Sphingosine kinases type 1(Sph K1),whose expression was markedly decreased in SIH,was identified as a novel target of mi R-335.Mi R-335 overexpression substantially reduced the expression of Sphk1 and promoted neural apoptosis,and its inhibition had opposite effects.Re-introduction of Sphk1 dramatically abrogated the apoptosis induced by mi R-335.This study provides the first systematic dissection of the RVLM mi RNA landscape in SIH.(1)Mi R-335 and mi R-674-3p considered as SIH promoters,can promote the occurrence and development of SIH.(2)The identified mi R-335/Sphk1/apoptosis axis represents one of the possible mechanisms.(3)Mi R-335 and mi R-674-3p can be exploited as potential targets for the molecular-based therapy of SIH.