Amplified pathogenic actions of angiotensin II in cysteine‐rich LIM‐only protein 4–negative mouse hearts

Abstract

LIM domain proteins have been identified as essential modulators of cardiac biology and pathology; however, it is unclear which role the cysteine-rich LIM-only protein (CRP)4 plays in these processes. In studying CRP4 mutant mice, we found that their hearts developed normally, but lack of CRP4 exaggerated multiple parameters of the cardiac stress response to the neurohormone angiotensin II (Ang II). Aiming to dissect the molecular details, we found a link between CRP4 and the cardioprotective cGMP pathway, as well as a multiprotein complex comprising well-known hypertrophy-associated factors. ignificant enrichment of the cysteine-rich intestinal protein (CRIP)1 in murine hearts lacking CRP4, as well as severe cardiac defects and premature death of CRIP1 and CRP4 morphant zebrafish embryos, further support the notion that depleting CRP4 is incompatible with a proper cardiac development and function. Together, amplified Ang II signaling identified CRP4 as a novel antiremodeling factor regulated, at least to some extent, by cardiac cGMP.-Straubinger, J., Boldt, K., Kuret, A., Deng, L., Krattenmacher, D., Bork, N., Desch, M., Feil, R., Feil, S., Nemer, M., Ueffing, M., Ruth, P., Just, S., Lukowski, R. Amplified pathogenic actions of angiotensin II in cysteine-rich LIM-only protein 4 negative mouse hearts.

Cyclic GMP-Dependent Regulation of Vascular Tone and Blood Pressure Involves Cysteine-Rich LIM-Only Protein 4 (CRP4)

“…Ca 2+ -measurements revealed, at least partly, an impaired ability of CRP4 KO VSMCs to reduce agonist-induced Ca 2+ -transients via the cGMP pathway (Figure 2). This is counterintuitive with a previous finding, implying that CRP4-deficient mice exhibit a mild, but significant hypotension in vivo [57], although BP regulation in vivo involves baroreceptors, nervous and the endocrine systems, renal and cardiac functions in addition to changes in vascular contractility, i.e., the agonist-induced and cGMP-modulated Ca 2+ response of VSMCs.…”

“…If this translates to the in vivo situation, BP regulation in CRP4-deficient mice should differ from CRP4 WT. Thus, we performed BP measurements in conscious CRP4 WT and CRP4 KO mice using implantable telemetry devices, which recorded every 30 s for a duration of 15 s [57,75]. First, we confirmed our previous finding of mild hypotonia in CRP4-deficient animals (Figure 4A, Supplementary Figure S4A) [57].…”

“…To affirm previously published data regarding potential sources of CRP4 [58,61], we assessed aortic sections derived from CRP4-deficient mice in comparison to respective littermate controls (CRP4 WT) [57]. Immunofluorescence (IF)-based visualization revealed for CRP4 high abundance in the medial layer of the vessel, whereas tissue obtained from CRP4 KO mice remained unstained (Figure 1A).…”

“…Lack of CRP4 resulted in increased cardiac mass and significant interstitial fibrosis, as well as in a functional decline of the heart during chronic Ang II exposure. These effects were at least partly mediated through the direct interaction of CRP4 with cGKI in the remodeled myocardium [57]. In addition to this cardiac phenotype, baseline BP of mice globally lacking CRP4 (CRP4 KO) was lower.…”

IRAG1 Deficient Mice Develop PKG1β Dependent Pulmonary Hypertension

“…These experiments were performed on a different cohort of mice, aged between 13 and 15 weeks, than the cohort that have been used for Echocardiography and right heart catheterization procedure. Standard protocols were followed as mentioned elsewhere [ 21 , 22 ]. Serial sections were performed (4 µm; used for H & E- and Sirius Red staining).…”