Histone demethylase LSD1 deficiency during high-salt diet is associated with enhanced vascular contraction, altered NO-cGMP relaxation pathway, and hypertension

Abstract

Histone methylation, a determinant of chromatin structure and gene transcription, was thought to be irreversible, but recent evidence suggests that lysine-specific demethylase-1 (LSD1, Kdm1a) induces demethylation of histone H3 lysine 4 (H3K4) or H3K9 and thereby alters gene transcription. We previously demonstrated a human LSD1 phenotype associated with salt-sensitive hypertension. To test the hypothesis that LSD1 plays a role in the regulation of blood pressure (BP) via vascular mechanisms and gene transcription, we measured BP and examined vascular function and endothelial nitric oxide (NO) synthase (eNOS) expression in thoracic aorta of male wild-type (WT) and heterozygous LSD1 knockout mice (LSD1(+/-)) fed either a liberal salt (HS; 4% NaCl) or restricted salt diet (LS; 0.08% NaCl). BP was higher in LSD1(+/-) than WT mice on the HS diet but not different between LSD1(+/-) and WT mice on the LS diet. Further examination of the mechanisms of this salt-sensitive hypertension in LSD1(+/-) mice on the HS diet demonstrated that plasma renin activity and plasma levels and urinary excretion of aldosterone were less in LSD1(+/-) than WT, suggesting suppressed renin-angiotensin-aldosterone system. In contrast, phenylephrine (Phe)-induced aortic contraction was greater in LSD1(+/-) than WT mice on the HS diet. Treatment of aortic rings with 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; a blocker of guanylate cyclase) enhanced Phe contraction in LSD1(+/-) compared with WT mice on the HS diet. Acetylcholine (Ach)-induced relaxation was less in LSD1(+/-) than WT mice on the HS diet. Endothelium removal or pretreatment with N(ω)-nitro-L-arginine methyl ester (blocker of NOS) or ODQ abolished Ach-induced relaxation in aorta of WT but had minimal effect in LSD1(+/-). Vascular relaxation to sodium nitroprusside, an exogenous NO donor and guanylate cyclase activator, was decreased in LSD1(+/-) vs. WT mice on the HS diet. RT-PCR and Western blots revealed decreased eNOS mRNA expression and eNOS and guanylate cyclase protein in the heart and aorta of LSD1(+/-) compared with WT mice on HS diet. Thus, during the HS diet, LSD1 deficiency is associated with hypertension, enhanced vascular contraction, and reduced relaxation via NO-cGMP pathway. The data support a role for LSD1-mediated histone demethylation in the regulation of NOS/guanylate cyclase gene expression, vascular function, and BP during the HS diet.

Lysine-specific demethylase-1 modifies the age effect on blood pressure sensitivity to dietary salt intake

“…This result is consistent with previous studies in humans, where low renin hypertensives hyperexcreted a salt load in contrast to normotensives or non-modulating hypertensives (a normal renin form of salt-sensitive hypertension) (Cottier et al 1958;Krakoff et al 1970;Luft et al 1977;Rydstedt et al 1986;Hollenberg et al 1986). In this study (data not shown) and previously (Pojoga et al 2011b), renin and aldosterone levels were suppressed in LSD1-deficient mice on HS diet, indicating that activation of the RAS is not a driving force for elevated blood pressure. As the renal vascular response is a major determinant for the ability to handle a Na + load, and LSD1 +/− mice showed enhanced vasoconstriction and impaired vasorelaxation when challenged with HS (Pojoga et al 2011b), early exaggerated natriuresis is thought to be an indicator of altered renal vascular function, which could contribute to the development of hypertension though the exact mechanisms remain unknown.…”

“…In this study (data not shown) and previously (Pojoga et al 2011b), renin and aldosterone levels were suppressed in LSD1-deficient mice on HS diet, indicating that activation of the RAS is not a driving force for elevated blood pressure. As the renal vascular response is a major determinant for the ability to handle a Na + load, and LSD1 +/− mice showed enhanced vasoconstriction and impaired vasorelaxation when challenged with HS (Pojoga et al 2011b), early exaggerated natriuresis is thought to be an indicator of altered renal vascular function, which could contribute to the development of hypertension though the exact mechanisms remain unknown.…”

“…Blood pressure was measured using a CODA noninvasive blood pressure system (KENT Scientific) applying the occlusion/volume pressure tail cuff method as described by us previously (Pojoga et al 2008(Pojoga et al , 2010(Pojoga et al , 2011b. Briefly, during blood pressure measurements, the mice were placed in a mouse restraint holder (KENT Scientific) and set on top of a heating platform to maintain body temperature to 37±1°C.…”

“…We have reported previously that hypertensive AfricanAmerican minor allele carriers of the LSD1 single nucleotide polymorphism (SNP) (rs587168) display increased blood pressure sensitivity to dietary salt intake (Williams et al 2012). Moreover, results from studies in LSD1 heterozygous knockout (LSD1 +/− ) mice on a high salt diet showed impaired vascular function compared to wild-type animals, as well as suppression of the renin-angiotensin system (RAS) (Pojoga et al 2011b).…”

Epigenetic Modification ofSod2in the Development of Diabetic Retinopathy and in the Metabolic Memory: Role of Histone Methylation

“…33 Histone H3K4 methylation and LSD1 are considered as essential epigenetic targets in cancer cells, 34 and LSD1-mediated histone demethylation is associated with hypertension and enhanced vascular contraction. 35 LSD1 specifically demethylates mono-or dimethylated H3K4 and H3K9, and removal of methyl groups from H3K4 is linked with transcriptional repression. 20 High glucose exposure of human aortic microvascular endothelial cells, in addition to increasing methylation of H3K4 and hypomethylation of H3K9, also increases the recruitment of LSD1 at the promoter of p65 subunit of NF-kB, and this is considered as one of the mechanisms associated with the activation of NF-kB.…”