McNamara, Dennis M.

This study uncovers a previously unrecognized role for NAV3 in TGF-β1-driven cardiac fibroblast activation. We show that NAV3 facilitates profibrotic remodeling through noncanonical signaling and cell cycle arrest, independently of SMAD2/3. These findings position NAV3 as a novel regulator of fibroblast phenotype and a potential modulator of cardiac fibrosis.

Abstract Introduction Cannabidiol has been shown to exert significant anti-inflammatory effects and has demonstrated efficacy in murine models of autoimmune myocarditis, pericarditis, and heart failure. The ARCHER Study assessed whether a pharmaceutically produced cannabidiol formulation showed beneficial effects on cardiac magnetic resonance (CMR) endpoints known to predict prognosis in this patient population. Methods In a multicentre international double-blind placebo-controlled phase 2 study, we randomly assigned 109 patients within 10 days of CMR confirmed diagnosis of acute myocarditis to 12 weeks of pharmaceutically produced oral cannabidiol (active) or placebo. Dose was titrated up to 10 mg/kg of body weight twice daily. Primary endpoints were the difference in extracellular volume (ECV) and global longitudinal strain (GLS) measured by CMR at week 12. Other CMR endpoints included left-ventricular ejection fraction (LVEF), LV mass, intracellular volume (ICV), LV end-diastolic and end-systolic volumes (LVEDV, LVESV), and left-atrial end-systolic volume (LAESV). Results All randomized patients (56 active/53 placebo) completed the study with no loss to follow-up. Study drug appeared safe and well tolerated. Baseline mean ECV 38.9 ± 10.9 ml, GLS −15.3 ± 3.6%, and LVEF 60.6 ± 9.9% were consistent with mild to moderate myocarditis and predominantly intact LV function. Week 12 mean ECV was 33.6 ml in the active group and 37.3 ml in the placebo group, a difference of −3.7 ml, confidence interval (CI): −7.4 to 0.1; P = .0538; GLS was −16.0% in the active group and −15.9% in the placebo group, difference of −0.1, CI: −1.2 to 1.1; P = .90. Left ventricular mass was significantly reduced in the active group at 121.1 g compared to placebo 130.3 g, a difference of −9.2, CI: −16.4 to −2.1; P = .0117. In terms of remodelling, LAESV was significantly reduced in the active group (−8.1 ml; P = .0376) while the reduction in LVEDV failed to reach significance (−7.4 ml; P = .098). Conclusion In mild-to-moderate acute myocarditis, treatment with pharmaceutically manufactured cannabidiol was not associated with a statistically significant change in myocardial ECV or GLS, although a trend towards reduction in ECV was observed. In addition, improvement in other potential markers of myocardial recovery, including a significant reduction in LV mass, was seen in the active treatment group. Further investigation of the therapeutic potential of this therapy in inflammatory cardiac conditions is warranted.

Background: Dilated Cardiomyopathy (DCM) is a major cause of heart failure (HF) and carries a high mortality rate. Drug treatment response for DCM-related HF patients is highly variable, with some patients having no response. A pharmacogenomic approach, genome-wide association study (GWAS) followed by biologically functional validation, can potentially identify genetic determinants of prognosis in DCM and might provide insight into novel biology of DCM pharmacotherapy. Methods: A GWAS was performed using DNA from 686 patients with recent onset DCM who were on standard HF therapy using change in left ventricular ejection fraction (LVEF) at a median of 6 months after initial diagnosis. Cultured human cardiac fibroblasts (HCFs) were used to functionally validate the GWAS findings in vitro . RNA-seq followed by pathway analysis after NAV3 knock-down (KD) using siRNA in HCFs were performed to explore potential biological mechanisms. Results: A genetic variant, rs11105445(G>A), identified from the GWAS, mapping to the neuron navigator 3 (NAV3) gene (rs11105445, p=2.37E-07; beta 2.74 ± 0.53) was associated with improvement in LVEF. Functional genomic experiments demonstrated that, both in LV tissue and in cultured fibroblasts, the minor allele A was associated with decreased transcription of NAV3 (pvalue: 0.0335 and 0.0432) suggesting that ↓NAV3 expression might be associated with improvement in LVEF. TGF-β1 can induce HCF transdifferentiation into myofibroblasts and we demonstrate that it also increases NAV3 expression. NAV3 KD which mimics the GWAS variant significantly suppressed TGF-β1 induced HCF transdifferentiation demonstrated by decreased expression of α-smooth muscle actin (ACTA2) and collagen I (COL1A1). RNA-seq after NAV3 KD followed by pathway analysis suggested that NAV3 exerted its effect by regulating ECM and cell cycle processes, especially G1/S transition. We demonstrate that NAV3 KD suppressed TGF-β1 induced G1/S arrest by regulating CDK4, CDK6 and INK4B (cyclin-dependent kinase inhibitor 2B/P15, CDK4 inhibitor). Conclusion: Decreased expression of NAV3 is associated with myocardial recovery in DCM, most likely due to its role in suppressing HCF differentiation by regulating TGF-β1 induced G1/S arrest. The role of NAV3 as a novel therapeutic target in DCM needs to be explored.

Abstract Aims Acute myocarditis, although a rare disease, can be associated with sudden cardiac death or the need for transplantation in both children and young adults. To date, there is no definitive evidence to support the routine use of immunosuppressive therapy or treatment targeting inflammation in patients with myocarditis. Animal models of cardiovascular (CV), as well as neurological diseases, have demonstrated that cannabidiol has significant anti-inflammatory properties and may represent a promising therapy in acute myocarditis. This efficacy has been shown in a murine model of autoimmune myocarditis as well as in in vitro and in vivo models of heart failure (HF). Methods and results We present the rationale and design of the ARCHER Trial, an international multicentre, double-blind, randomized, placebo-controlled, phase II study examining the safety and efficacy of a pharmaceutically produced cannabidiol formulation, in patients with mild to moderate acute myocarditis. Eligible patients are those with acute myocarditis, randomized within 10 days of the diagnostic cardiac MRI (CMR), which has met defined diagnostic criteria for myocarditis. Oral treatment (cannabidiol or placebo) is titrated from 2.5 mg/kg of body weight up to 10 mg/kg of body weight b.i.d. (or highest tolerated dose) and taken for 12 weeks in addition to standard of care therapy for HF. The primary endpoints are defined as changes in global longitudinal strain (GLS) and extra cellular volume (ECV), measured by CMR at 12 weeks. Assuming 80% power, a 5% alpha risk and 25% missing CMR follow-up data at Week 12, 100 patients are required to demonstrate the desired treatment effect of 18%. The change in left ventricular ejection fraction (LVEF) from baseline to Week 12 was selected as the secondary endpoint. Additional exploratory endpoints include changes in hs-troponin, NT-proBNP, markers of inflammation and endothelial function during the 12-week treatment period. The trial is ongoing but is now more than 50% recruited. As enrolment in the trial continues, no interim data are available for inclusion in this Design paper. Conclusions The ongoing ARCHER Trial is an international, multicentre, double-blind, randomized, placebo-controlled phase II study, designed to determine the effect of a pharmaceutically produced cannabidiol formulation on CMR parameters in patients presenting with acute myocarditis. Enrolment of 100 patients is expected to conclude in Q3 2024. Study results will be available in early 2025.

Introduction: IL2 soluble receptor (IL2Rs) and neopterin (NPT) are peripheral markers of T cell and monocyte activation investigated extensively in auto-immune disorders. We assessed these biomarkers in subjects with non ischemic cardiomyopathy of recent onset (ROCM) from the IMAC2 (Intervention in Myocarditis and Acute Cardiomyopathy) registry. We compared the degree of cellular activation in peripartum cardiomyopathy (PPCM) with that evident in non-peripartum women and men with ROCM. Methods: 130 subjects were investigated: 96 subjects with ROCM including 37 women with PPCM (group 3), 27 non-peripartum women (group 2) and 32 men (group 1), and 34 controls without cardiac disease (CTL). All subjects with ROCM had serum obtained at entry and an assessment of LVEF by transthoracic echocardiography. LVEF was reassessed 6 months after enrollment. Results: The ROCM cohort (n=96, 64F/32M, mean age 30±6) had a mean LVEF at baseline of 0.24±0.08 which increased to 0.43±0.13 at 6 months. For controls (mean age 45±6, 24F/10M) the mean LVEF was 0.58±0.10. Both IL2Rs and NPT were markedly elevated in ROCM subjects compared to controls (IL2Rs: ROCM=1411±671, CTL=970±329 pg/ml, p<0.001; NPT: ROCM=9.2±5.6, CTL=6.2±3.1 nmol/l, p=0.003). Increased NYHA class was associated with higher serum levels for both NPT (p=0.013) and IL2Rs (p=0.009). No differences were evident in subjects with PPCM versus men and women with ROCM for either IL2Rs (group 1/2/3 =1524±504/1531±904/1225±566 pg/ml, p=0.10) or NPT (group 1/2/3=9.4±6.5 /9.3±5.8 /8.9±4.7 nmol/l, p=0.92). IL2Rs levels were lower in black subjects: blacks (n=25) IL2Rs=1123±496; whites (n=71) 1513±698, p=0.012. Levels of IL2Rs and NPT did not predict the degree of recovery at 6 months, although there was a nonsignificant trend towards more recovery with lower IL2Rs levels. Conclusions: Marked elevation of IL2Rs and NPT, biomarkers of cellular immune activation, are evident in subjects with ROMC. The degree of activation in subjects with PPCM appears similar to that seen in men and non-peripartum women with ROCM, suggesting similar inflammatory pathogenesis for these syndromes of acute heart failure. The relationship of cellular activation to myocardial injury and recovery in ROCM should be further investigated.

Peripartum cardiomyopathy (PPCM) is an idiopathic form of pregnancy-induced heart failure associated with preeclampsia. Circulating factors in late pregnancy are thought to contribute to both diseases, suggesting a common underlying pathophysiological process. However, what drives this process remains unclear. Using serum proteomics, we identified the senescence-associated secretory phenotype (SASP), a marker of cellular senescence associated with biological aging, as the most highly up-regulated pathway in young women with PPCM or preeclampsia. Placentas from women with preeclampsia displayed multiple markers of amplified senescence and tissue aging, as well as overall increased gene expression of 28 circulating proteins that contributed to SASP pathway enrichment in serum samples from patients with preeclampsia or PPCM. The most highly expressed placental SASP factor, activin A, was associated with cardiac dysfunction or heart failure severity in women with preeclampsia or PPCM. In a murine model of PPCM induced by cardiomyocyte-specific deletion of the gene encoding peroxisome proliferator–activated receptor γ coactivator-1α, inhibiting activin A signaling in the early postpartum period with a monoclonal antibody to the activin type II receptor improved heart function. In addition, attenuating placental senescence with the senolytic compound fisetin in late pregnancy improved cardiac function in these animals. These findings link senescence biology to cardiac dysfunction in pregnancy and help to elucidate the pathogenesis underlying cardiovascular diseases of pregnancy.

Background: We have previously demonstrated by performing a genome-wide association study that a genetic locus resulting in ↓CDCP1 expression was associated with myocardial recovery in patients with dilated cardiomyopathy (DCM). We have subsequently shown that ↓CDCP1 decreases human cardiac fibroblast proliferation in vitro , however, its potential role in modulating cardiac fibrosis and function in vivo is unknown. Methods: A Cdcp1 knock-out (KO) mouse was generated on FVB/NJ background. Angiotensin II/Phenylephrine (AngII/PE) or saline was infused by an osmotic pump into mice ( Cdcp1 KO n=20; wild type/wt n=18) for 4 weeks. Echocardiography was performed at 0 and 4 weeks. Picrosirius red (PSR) staining was performed on cross-sectional heart tissue to identify cardiac fibrosis, which was quantified, using ImageJ software, as a percentage of left ventricular (LV) area stained by PSR. Results: LV mass index (LVMI) significantly increased in AngII/PE wt mice as compared to saline wt (figure a. 3.65±0.15 mg/g vs 3.05±0.17mg/g, p=0.01), however, AngII/PE Cdcp1 KO mice had significantly decreased LVMI as compared to AngII/PE wt mice (figure a. 3.17±0.09 mg/g vs 3.65±0.15 mg/g, p=0.01). In addition, fractional shortening trended higher in AngII/PE Cdcp1 KO mice as compared to AngII/PE wt mice (figure b. 50.36±2.06% vs 45.48±1.43%, p=0.07). Extent of cardiac fibrosis was significantly higher in AngII/PE wt mice as compared to saline wt (figure c. 15.79±0.49% vs 7.93±0.39%, p<0.0001), however AngII/PE Cdcp1 KO mice had significantly reduced cardiac fibrosis as compared to AngII/PE wt mice (figure c. 9.41±0.43%, p<0.0001). Conclusions: CDCP1 KO significantly reduces pressure over-load induced LV hypertrophy and cardiac fibrosis. Its role as a novel therapeutic target in attenuating fibrosis and improving cardiac function in DCM needs to be further explored.

BACKGROUND: Dilated cardiomyopathy (DCM) is a major cause of heart failure and carries a high mortality rate. Myocardial recovery in DCM-related heart failure patients is highly variable, with some patients having little or no response to standard drug therapy. A genome-wide association study may agnostically identify biomarkers and provide novel insight into the biology of myocardial recovery in DCM. METHODS: A genome-wide association study for change in left ventricular ejection fraction was performed in 686 White subjects with recent-onset DCM who received standard pharmacotherapy. Genome-wide association study signals were subsequently functionally validated and studied in relevant cellular models to understand molecular mechanisms that may have contributed to the change in left ventricular ejection fraction. RESULTS: The genome-wide association study identified a highly suggestive locus that mapped to the 5′-flanking region of the CDCP1 (CUB [complement C1r/C1s, Uegf, and Bmp1] domain containing protein 1) gene (rs6773435; P =7.12×10 −7 ). The variant allele was associated with improved cardiac function and decreased CDCP1 transcription. CDCP1 expression was significantly upregulated in human cardiac fibroblasts (HCFs) in response to the PDGF (platelet-derived growth factor) signaling, and knockdown of CDCP1 significantly repressed HCF proliferation and decreased AKT (protein kinase B) phosphorylation. Transcriptomic profiling after CDCP1 knockdown in HCFs supported the conclusion that CDCP1 regulates HCF proliferation and mitosis. In addition, CDCP1 knockdown in HCFs resulted in significantly decreased expression of soluble ST2 (suppression of tumorigenicity-2), a prognostic biomarker for heart failure and inductor of cardiac fibrosis. CONCLUSIONS: CDCP1 may play an important role in myocardial recovery in recent-onset DCM and mediates its effect primarily by attenuating cardiac fibrosis.

Abstract Background A genome-wide association study (GWAS) assessing change in left ventricular ejection fraction (LVEF) in dilated cardiomyopathy (DCM), a surrogate marker of morbidity and mortality in heart failure (HF), had not been performed previously and could provide insight into novel biological pathways that could lead to the development of new drugs that might target myocardial recovery. The presence and extent of cardiac fibrosis in DCM is independently associated with myocardial recovery and cardiovascular mortality. Purpose To identify the biological relevance of genetic targets that are associated with change in LVEF in patients with DCM. Methods A GWAS was performed using DNA from 686 patients with recent onset DCM who were on standard HF therapy using change in LVEF at a median of 6 months after initial diagnosis. Cultured human cardiac fibroblasts (HCFs) were used as an in vitro model to study the functional and biological relevance of the gene target identified in the GWAS. Specifically, HCFs were transfected with siRNA by using the Lipofectamine™ RNAiMAX Transfection Reagent for gene knockdown (KD). RNA-seq was performed using the Illumina TruSeq protocol with expression analysis conducted with the EdgeR package. Ingenuity Pathway Analysis was used. Results A single-nucleotide polymorphism, rs11105445(G&gt;A), mapping to the neuron navigator 3 (NAV3) gene (rs11105445, p=2.37E-07; beta 2.74±0.53) was associated with improvement in LVEF. We performed a phenome-wide association study using data from the UK Biobank and demonstrated that genetic variation in NAV3 was significantly associated with HF mortality (p=3.2E-28), highlighting the potential importance of this gene in HF. Using GTEx data we demonstrated that in LV tissue the minor allele A was associated with ↓NAV3 expression (p=0.03) suggesting that ↓NAV3 expression might be associated with improvement in LVEF. We demonstrated that NAV3 KD significantly ↓TGF-β1 mediated HCF transdifferentiation into myofibroblasts, ↓α-smooth muscle actin (ACTA2) and ↓collagen I (COL1A1), therefore NAV3 KD was anti-fibrotic (see Figure 1), 1a. HCFs treated by vehicle/TGF-β1 after KD of NAV3/ctrl, and ACTA2 and COL1A1 were analyzed by qPCR; 1b. Representative immunofluorescence staining for α-SMA (in green), RNA-seq after NAV3 KD followed by pathway analysis suggested that NAV3 exerted its effect by regulating cell cycle related proteins (Figure 2), 2a. Volcano plot shows significant differentially expressed genes identified by RNA-seq analysis (down-regulated in blue, up-regulated in red); 2b. NAV3 KD significantly increased expression of cell cycle related proteins, which was validated by Western blot. Conclusions Decreased expression of NAV3 is associated with myocardial recovery in DCM, most likely due to its anti-fibrotic effect via direct regulation of cell cycle proteins. The role of NAV3 as a novel therapeutic target in DCM needs to be explored. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Mayo Clinic Center for Individualized MedicineMayo Clinic Department of Cardiovascular Medicine

Introduction : The incidence of spontaneous clinical improvement in acute cardiomyopathy (ACM) patients treated with evidence based medical therapy is unknown. We hypothesized that pts without LV dilatation at presentation would have the greatest potential for recovery of ejection fraction (EF). Methods: A multi-center NHLBI sponsored trial, Intervention in Myocarditis and Acute Cardiomyopathy II (IMAC 2) was designed to study the clinical course of ACM and the mechanisms associated with outcomes. A clinical, echocardiography, and genetics core lab are established. Results: 15 centers have enrolled 215 pts, mean age 45 ± 14 yrs, 34% female, NYHA class I–IV% 18/54/21/7, baseline EF 0.25 ± 0.09. Therapy included 80% beta blockers and 92% ACE or ARB treated. All patients enrolled had symptoms for ≤ 6 mos and were diagnosed with acute, idiopathic cardiomyopathy or myocarditis. Baseline and 6 mo echoes in 140 pts reviewed by the core lab demonstrated increased ejection fraction (EF): 0.25 ± 0.09 to 0.40 ± 0.11 p<0.001; mean increase 0.15 ± 0.10. Recovery in EF from baseline to 6 mos was related to LVEDD at baseline as shown in the Figure . Kaplan Meier survival n=207 at 1 and 2 years 96% and 94% and transplant free survival at 1 and 2 yrs 92% and 91%. Conclusions: Results of IMAC 2 reveal a marked spontaneous improvement in EF over 6 months, greatest in those with non-dilated LVEDD at baseline, and excellent overall survival in ACM pts treated with evidence based therapies.