Ghazal, Rachad

Abstract Human genomic studies link reduced CUB domain-containing protein 1 (CDCP1) expression with myocardial recovery in heart failure. While CDCP1 regulates cardiac fibroblast proliferation in vitro, it’s in vivo role in cardiac fibrosis remains unclear. Using a Cdcp1 -knockout (KO) angiotensin II/phenylephrine mouse model, we show that Cdcp1 deletion reduces echocardiographic left ventricular mass, histologic cardiac fibrosis, and pro-fibrotic gene expression, along with decreased fibroblast activation and inflammatory markers. Spatial transcriptomics identified a pressure overload–expanded fibroblast subpopulation enriched for growth factor and TGF-β signaling (FB5), which was markedly attenuated in Cdcp1 -KO hearts, alongside reduction of a pro-inflammatory cardiomyocyte subtype (CM4). Complementary studies in human ventricular fibroblasts demonstrate that CDCP1 knockdown reduced extracellular matrix gene expression and collagen I deposition. These findings establish CDCP1 as a regulator of cardiac fibrotic remodeling in vivo and open avenues for its further investigation as a potential therapeutic target.

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.

Background. Acute cellular rejection (ACR) remains a major cause of morbidity after heart transplantation despite advances in immunosuppression. Whole genome transcriptomic profiling offers a systems-based, unbiased approach to elucidate the molecular mechanisms underlying ACR. However, noninvasive, longitudinal biomarker assessments capable of capturing the temporal dynamics of rejection biology remain scarce. Methods. RNA sequencing of peripheral blood from heart transplant recipients before, during, and after ACR was compared with nonrejection controls. Pathway analysis was conducted using differentially expressed genes (DEGs), and a machine learning approach was applied to assess gene-based prediction of ACR. Results. A total of 235 rejection-specific significant DEGs and 863 postrejection DEGs (false discovery rate < 0.05) were identified. During ACR, DEGs were enriched for T-cell activation/differentiation, apoptosis, and B-cell receptor signaling pathways. By combining the 2 sets of DEGs, a panel of 71 common genes was identified that reflected the significant, longitudinal transcriptomic dynamics of ACR. In an elastic net machine learning–based classifier, DYNLL1 and SERF2 were identified as ACR predictive genes, and achieved a cross-validated area under the receiver operating characteristic curve of 0.63. Conclusions. Peripheral blood transcriptomics identify dynamic temporal responses in ACR including T- and B-cell pathways with potential ACR predictive genes that warrant further investigation.

Background: Cardiac fibrosis is a critical and independent driver of heart failure (HF), characterized by excessive extracellular matrix (ECM) deposition. Decreased CDCP1 (CUB domain-containing protein 1) expression has been associated with myocardial recovery in human genome wide association studies by attenuating PDGF-BB driven cardiac fibroblast proliferation with no effect on canonical TGF-beta mediated transdifferentiation in-vitro. In-vivo, Cdcp1 deletion significantly reduced cardiac fibrosis and dysfunction in an angiotensin II/phenylephrine-induced pressure overload mouse model. However, its upstream regulators and its downstream effects on molecular signaling pathways that modulate ECM remodeling are unknown. Hypothesis: CDCP1 promotes human cardiac fibroblast mediated ECM remodeling in the HF microenvironment. Methods: Human ventricular fibroblasts (HVF) were treated with PDGF-BB (20 ng/ml), TGF-β (10 ng/ml), or Angiotensin II (100 ng/ml) for 48 hours. CDCP1 knockdown (KD) was achieved through siRNA transfection. Gene expression analysis was performed using qRT-PCR and protein quantification by Western blot. Both intact HVF and decellularized ECM were immunostained for collagen 1 to evaluate for ECM compositional changes. Results: Individual and combination treatments with fibrotic stimuli significantly increased CDCP1 expression (Figure 1A-1B). CDCP1 KD resulted in reduction of key ECM markers COL1A1, CTGF, and LOX (Figure 1C) across all fibrotic stimuli . Immunostaining of HVF after treatment with fibrotic stimuli showed reduced collagen 1 production with CDCP1 KD (Figure 1D). Western blot analysis showed increased phosphorylation of Src (tyr416) with 6h of treatment with fibrotic stimuli which was nullified by silencing of CDCP1 (Figure 1E). Conclusion: Our findings demonstrate that CDCP1 is necessary for ECM synthesis and Src signaling across multiple profibrotic pathways. Selective targeting of CDCP1 to modulate Src signaling pathways could provide novel therapeutic avenues for HF and fibrosis treatment.

Background: Cardiac fibrosis is a central pathological process that leads to worse outcomes in various cardiomyopathies. Recent evidence shows that CDCP1 (CUB domain-containing protein 1) modulates myocardial recovery by attenuating human cardiac fibroblast (HCF) proliferation. This study investigates the hypothesis that selective targeting of the CDCP1 cleavage domain can mitigate fibroblast proliferation, thereby offering a novel therapeutic approach to reducing cardiac fibrosis. Methods: A high-throughput in silico screening was performed using the Enamine compound library, focusing on structural regions that include the cleavage and adjacent sites of CDCP1 . A total of 147 candidate compounds were prioritized based on docking scores and binding stability profiles. Selected compounds were subsequently evaluated in vitro using HCF cultures seeded at 3,000 cells/well in 96-well plates. Each compound was administered at 10 μM concentration, and cell proliferation and viability were assessed by time-lapse imaging in the Incucyte® system at 24 and 96 hours. All experiments were done in triplicate with appropriate DMSO vehicle controls. Results: Compound C3 significantly reduced HCF proliferation (Fig B) to 27.3±2.4% relative to DMSO controls (99.9±0.5%, P <0.001) at 96 hours. Detailed structural modeling indicated that C3 binds to the CDCP1 cleavage site (Fig C) with a favorable Glide XP docking score of -7.66 kcal/mol. The interaction is stabilized by hydrogen bonds with Lys365 and Cys374 (Fig D), and supplementary hydrophobic interactions between aromatic rings and aliphatic groups, which contribute to a strong inhibitory effect. Conclusion: Targeting the CDCP1 cleavage domain with compound C3 effectively diminishes HCF proliferation in vitro. Therefore, these results substantiate the therapeutic potential of CDCP1 inhibition in cardiac fibrosis. Ongoing in vivo studies will explore the translational relevance of these findings.

Background: Transcatheter aortic valve replacement (TAVR) is a well-established therapeutic option for all risk patients with symptomatic severe aortic stenosis (AS). While TAVR primarily addresses AS, its benefits extend beyond the valve itself. Recent studies suggest possible restoration of left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) following TAVR. This study aims to assess changes in LV GLS in patients undergoing TAVR, which may serve as a subclinical indicator of improved LV mechanics. Materials and Methods: This retrospective study included patients with severe AS who underwent TAVR at the American University of Beirut Medical Center from January 2017 to January 2023. Baseline and 1-year echocardiography parameters were compared, and GLS was calculated to assess the impact of TAVR on LV function. Results: A total of 80 patients (mean age: 81.3 ± 7.8 years; 38.8% of women; 88.8% hypertensive) who underwent TAVR for severe AS were included in the final analysis. One-year post-TAVR, echocardiographic studies showed a significant reduction in interventricular septum diameter (13.3 ± 2.3 mm vs. 12 ± 1.8 mm, P < 0.001) and LV mass index (LVMI) (113.6 ± 26.6 g/m 2 vs. 96 ± 30.3 g/m 2 , P < 0.001). LVEF showed a modest improvement (59.2 ± 12.3% vs. 62.1 ± 7.6%, P < 0.01). LV GLS significantly improved from −16.8 ± 4.6% to −19.2 ± 3.3% ( P < 0.001). Baseline LVMI, LVEF, and GLS correlate with the GLS change (ΔGLS) post-TAVR. Conclusion: GLS significantly improves 1 year after TAVR, indicating an overall improvement in LV performance. The degree of improvement in GLS correlates with baseline LVMI and systolic function.

Cardiac fibrosis, a hallmark of heart failure and various cardiomyopathies, represents a complex pathological process that has long challenged therapeutic intervention. High-throughput omics technologies have begun revolutionizing our understanding of the molecular mechanisms driving cardiac fibrosis and are providing unprecedented insights into its heterogeneity and progression. This review provides a comprehensive analysis of how techniques—encompassing genomics, epigenomics, transcriptomics, proteomics, and metabolomics—are providing insight into our understanding of cardiac fibrosis. Genomic studies have identified novel genetic variants and regulatory networks associated with fibrosis susceptibility and progression, and single-cell transcriptomics has unveiled distinct cardiac fibroblast subpopulations with unique molecular signatures. Epigenomic profiling has revealed dynamic chromatin modifications controlling fibroblast activation states, and proteomic analyses have identified novel biomarkers and potential therapeutic targets. Metabolomic studies have uncovered important alterations in cardiac energetics and substrate utilization during fibrotic remodeling. The integration of these multi-omic data sets has led to the identification of previously unrecognized pathogenic mechanisms and potential therapeutic targets, including cell-type-specific interventions and metabolic modulators. We discuss how these advances are driving the development of precision medicine approaches for cardiac fibrosis while highlighting current challenges and future directions in translating multi-omic insights into effective therapeutic strategies. This review provides a systems-level perspective on cardiac fibrosis that may inform the development of more effective, personalized therapeutic approaches for heart failure and related cardiovascular diseases.

Background and purpose: Aortic stenosis (AS) poses significant healthcare challenges, particularly in aging populations like Lebanon. Aortic valve replacement (AVR) is the primary treatment; however the choice between transcatheter aortic valve replacement (TAVR) and surgical AVR (SAVR) varies based on patient-specific factors. This study aimed to compare clinical outcomes between TAVR and SAVR in patients with severe AS at a Lebanese tertiary care center. Methods: This retrospective study included 453 patients aged ≥60 with severe AS who underwent either TAVR or SAVR at the American University of Beirut Medical Center from 2011 to 2022. Primary outcomes were 30-day mortality and hospital readmission rates. Secondary outcomes included length of stay, complications, and changes in echocardiographic parameters. Statistical analysis included Chi-squared tests, t-tests, and propensity score matching. Results: Of the 453 patients, 306 underwent TAVR, and 147 underwent SAVR, with a mean age of 79.0 ± 6.8 years. The TAVR group had higher Society of Thoracic Surgeons (STS) scores (4.7 ± 3.2 vs. 2.6 ± 1.7; P < 0.001). TAVR patients had shorter hospital stays (2 [0-93] vs. 6 [4-41] days; P < 0.001), lower 30-day readmission rates (8.2% vs. 18.5%; P = 0.002), and similar all-cause mortality rates (hazard ratio [HR]: 0.69; 95% confidence interval [95% CI]: 0.14–3.42; P = 0.647). Post-procedural new-onset left bundle branch block (LBBB) was more common in TAVR group (13.0% vs. 0.6%; P < 0.001), and new-onset atrial fibrillation (Afib) was more frequent in the SAVR group (34% vs. 1%; P < 0.001). There were no significant differences in the rates of complete heart block (CHB) or pacemaker implantation. The effective orifice area index (EOAi) was higher in the TAVR group (1.2 ± 0.4 vs. 0.9 ± 0.2 cm2/m2; P < 0.001). Major bleeding complications were significantly lower in TAVR patients (7.9% vs. 65.8%; P < 0.001), with no significant differences in neurological events. Conclusions: Both TAVR and SAVR show comparable safety and efficacy, with TAVR offering advantages in terms of recovery time and bleeding risk. These findings support a tailored approach to procedural choice based on individual patient risk profiles.

Background: Bilateral cardiac sympathetic denervation (BCSD) has shown promise in treating patients with nonischemic cardiomyopathy (NICM) suffering from refractory multifocal premature ventricular contractions (PVCs) and ventricular tachycardia (VT). Despite its growing use, the effectiveness of BCSD across different NICM etiologies has not been extensively studied. Research Question: How effective is BCSD across a variety of NICM etiologies? Goals: To evaluate the effectiveness of BCSD on left ventricular ejection fraction (LVEF) and PVC burden in patients with NICM. Methods: We conducted a subset analysis on a previous retrospective, observational study of NICM patients who underwent BCSD. Eight NICM etiologies were assessed. Results: 43 NICM patients underwent BCSD (mean age 52.3±14.7 years; 30% females). Overall, LVEF significantly improved (38.7±7.9% to 46.2±9.6%, p <0.001), and PVC burden (PVCb) significantly decreased (23.7±9.9% to 1.3±1%, p <0.001). A similar phenomenon was seen in idiopathic/dilated cardiomyopathy (CM) (LVEF: +8.7%, p <0.001; PVCb: -20.6%, p <0.001), post-viral CM (LVEF: +4.8%, p =0.2; PVCb: -24.2%, p <0.001), familial CM (LVEF: +10%; PVCb: +23.3%), giant cell CM (LVEF: +10%; PVCb: + 30.5%), and arrhythmogenic right ventricular CM (LVEF: +12.5%, p=0.09; PVCb -30.6%, p =0.001). Catecholaminergic polymorphic VT had a non-significant increase in LVEF (+5%, p=0.5) but a significant decrease in PVCb (-21.8%, p=0.02), whereas sarcoidosis had the opposite effect with significant increase in LVEF (LVEF: +13.4%, p=0.3) but non-significant decrease in PVCb (-16.1%, p=0.02). Lastly, hypertrophic CM remained unchanged in LVEF (30%) but PVCb decreased (-8%). Conclusion: BCSD demonstrates efficacy in improving LVEF and reducing PVCb across almost all NICM with refractory VT. However, a case-by-case evaluation is still needed for its use.

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.