| Objective:Studying the pathogenesis,treatment and intervention strategies of hypertension is an important scientific problem.Vasodilation is one of the most effective methods to lower blood pressure.In recent years,researchers have found that HDAC6 inhibitors can alleviate endothelial dysfunction induced by high-fat diet.However,most HDAC6 inhibitors are not ideal for vasodilation,and their specific mechanism of action has not been elucidated.Therefore,this paper uses a novel HDAC6 inhibitor to study its effect on vascular relaxation regulation,its functional impact on hypertensive mice and its mechanism of regulating vascular tension,providing scientific theoretical basis and experimental data for future development of anti-hypertensive drugs targeting vascular tension regulation.Methods:In this study,the isolated vascular ring tension system was used to determine the vasodilation effect of a novel HDAC6 inhibitor,and compounds with good vasodilation effect were screened out as the research object.To analyze the potential action targets and possible mechanism pathways of novel HDAC6 inhibitors in the treatment of hypertension by using network pharmacology;The effects of a novel HDAC6 inhibitor on the relaxation of vascular rings with and without endothelial integrity in normal mice precontracted with phenylephrine(PE)were systematically analyzed using an isolated mouse thoracic aortic vascular ring model.The intact endothelium was pretreated with N-nitro-L-arginine methyl ester(L-NAME),a nitric oxide synthase inhibitor,and Indomethacin(Indo),an epoxy synthase inhibitor,to observe the effect of a novel HDAC6 inhibitor on the vascular tension of intact endothelium.L-NNA-induced hypertension mouse model was used,and normal C57BL/6 mice were used as the control group.The model groups were divided into three groups(model group,positive drug group and drug administration group).After four weeks of drug administration,serum Nitric Oxide(NO)and endothelin-1(ET-1)contents were measured,and the thoracic aorta was taken for in vitro vascular tension measurement,H&E staining and Masson staining.Immunohistochemistry was used to evaluate the effect of the compound on the expression of vasodilation-related protein.A novel HDAC6 inhibitor was used for Western Blot analysis and verification of the expression of relaxation-related proteins in human umbilical vein endothelial cells(HUVEC).Results:(1)HDAC6 inhibitor YPX-C-05 has the effect of relaxing blood vesselsAmong the five novel compounds(YPX-C-01,YPX-C-02,YPX-C-03,YPX-C-05,and YPX-C-06),only YPX-C-05(0.05mg/m L)was able to reverse PE-induced vasoconstriction of the mouse aorta and relax the blood vessels.The inhibitory effect of YPX-C-05 on HDAC6 was weaker than that of Tubastatin A,a selective inhibitor of HDAC6.However,the vasodilation effect of YPX-C-05 was significantly stronger than that of Tubastatin A in the range of 0.01 mg/m L to 0.3 mg/m L.(2)Network pharmacology was used to analyze the mechanism of YPX-C-05 in the treatment of hypertensionNetwork pharmacology analysis showed that the pathway with the highest correlation with hypertension in vascular relaxation was PI3K/Akt pathway,and potential action targets of YPX-C-05 in the treatment of hypertension were analyzed as VEGFA,SRC,MP9,MMP2,and PTGS2.(3)YPX-C-05 endothelium-dependent relaxation of thoracic aortic vascular ring in miceCompared with the endothelial intact vascular ring,the vascular relaxation effect of YPX-C-05 after endothelial removal is significantly reduced in the concentration range of0.01 mg/m L to 0.1 mg/m L,indicating that the vascular response of YPX-C-05 to the Phe pre-contracted artery is endothelium-dependent vasodilation.(4)The endothelium-dependent vasodilation of YPX-C-05 may be related to the NO-CGMP pathwayThe endothelial intact vascular rings were preincubated with an e NOS inhibitor(L-NAME)and a COX inhibitor(Indo).Compared with the control group,YPX-C-05 significantly reduced the Phe-induced vasoconstriction in the concentration range of 0.01mg/m L to 0.1 mg/m L after L-NAME pre-incubation.YPX-C-05 showed no significant change in the Phe-induced vasoconstriction following preincubation with Indo.These results indicated that the vasodilation effect of YPX-C-05 was related to the NO-CGMP pathway.(5)YPX-C5 could effectively reduce the acute hy PErtension induced by pe in miceAfter intraperitoneal injection of PE into the mice,YPX-C-05 was injected intraperitoneally to determine the changes in systolic and diastolic blood pressures in C57 mice.PE could acute increase systolic and diastolic blood pressure in mice,while YPX-C-05 could significantly reduce the systolic and diastolic blood pressure increases induced by PE.These results indicated that YPX-C-05 could completely reverse the changes in blood pressure of PE-induced mice.(6)YPX-C-05 could repair the vascular structure and function of hypertensive miceYPX-C-05 was able to repair the vascular injury induced by N’-nitro-L-arginine(N’-nitro-L-arginine,L-NNA)in hypertensive mice within four weeks,improve vasoconstriction,reconstruct the vascular wall structure,and reduce the accumulation of collagen and fibrosis.(7)YPX-C-05 regulated the diastolic function of blood vessels through AKT/e NOS/NO pathwayTreatment with YPX-C-05 increased the positive expression of eNOS in mouse blood vessels and reversed the inhibition of PE on the phosphorylation levels of Akt and e NOS in HUVEC.Conclusion:The novel HDAC6 inhibitor YPX-C-05 may inhibit HDAC6,activate the AKT/e NOS/NO pathway,enhance the phosphorylation of Akt,promote the phosphorylation of downstream e NOS,and increase the generation of NO,thereby regulating the relaxation function of blood vessels,and can effectively It can effectively repair the function and structure of blood vessels in hypertensive mice,remodel blood vessel walls,reduce collagen deposition and fibrosis. |
