Dixon, A. J. | Search bioRxiv

bioRxiv2025

Ovarian Hormones Moderate Hypertension in Female Eln Haploinsufficient Mice

Hypertension is a hallmark of cardiovascular abnormalities associated with Williams syndrome (WS), a rare genetic disorder involving microdeletion of genes on human chromosome 7, including the elastin gene (ELN). Heterozygous deletion of Eln (Eln+/-) in mice recapitulates hypertension and arteriopathy associated with WS. Previously, differences in blood pressure elevation and sensitivity to dietary sodium were found to be less profound in female Eln+/- mice. Here, we determined whether ovarian hormones play a role in sex-related difference in blood pressure elevation resulting from Eln haploinsufficiency. Female Eln+/+ and Eln+/- mice instrumented with radiotelemetry devices were subjected to sham surgery or ovariectomy (OVX). We found that OVX lowered diastolic but not systolic blood pressure (SBP) in Eln+/- mice, resulting in increased pulse pressure. In Eln+/- mice, diuresis induced by acute volume expansion was blunted, while anti-natriuresis was exaggerated. Furthermore, amiloride lowered SBP and increased urinary Na+ excretion, suggesting that Eln+/--induced hypertension may be Na+-dependent. We conclude that increased Na+ and water retention by the kidney contribute to hypertension resulting from Eln haploinsufficiency. The underlying mechanism involves the alteration of ovarian hormone effects in the kidney and sustained signaling downstream of the V2 receptor, leading to increased ENaC activity and water reabsorption. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=103 SRC="FIGDIR/small/689164v1_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@1ccfa15org.highwire.dtl.DTLVardef@369344org.highwire.dtl.DTLVardef@fe8194org.highwire.dtl.DTLVardef@ed285d_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO CDPC, cortical duct principal cell; ER, estrogen receptor; PR, progesterone receptor; ENaC, epithelial sodium channel; AQP2, aquaporin 2; V2R, vasopressin V2 receptor; ELN, elastin; PKA, protein kinase A; AC, adenylyl cyclase; Gs, stimulatory G protein; ATP, Adenosine triphosphate; cAMP, cyclic AMP; {oplus}, activating; {ominus}, inhibiting C_FIG

physiology↗

bioRxiv2021

Targeting primary and metastatic uveal melanoma with a G protein inhibitor

Uveal melanoma (UM) is the most common intraocular tumor in adults. Nearly half of UM patients develop metastatic disease and often succumb within months because effective therapy is lacking. A novel therapeutic approach has been suggested by the discovery that UM cell lines driven by mutant constitutively active Gq or G11 can be targeted by FR900359 (FR) or YM-254890, which are bioavailable, selective inhibitors of the Gq/11/14 subfamily of heterotrimeric G proteins. Here, we have addressed the therapeutic potential of FR for UM. We found that FR inhibited all oncogenic Gq/11 mutants reported in UM. FR arrested growth of all Gq/11-driven UM cell lines tested, but induced apoptosis only in a few. Similarly, FR inhibited growth of, but did not efficiently kill, UM tumor cells from biopsies of primary or metastatic tumors. FR evoked melanocytic redifferentiation of UM tumor cells with low (class 1), but not high (class 2), metastatic potential. FR administered systemically below its LD50 strongly inhibited growth of PDX-derived class 1 and class 2 UM tumors in mouse xenograft models, and reduced blood pressure transiently. FR did not regress xenografted UM tumors, or significantly affect heart rate, liver function, hematopoiesis, or behavior. These results indicated the existence of a therapeutic window in which FR can be explored for treating UM, and potentially other diseases caused by constitutively active Gq/11.

cancer biology↗