JACC: Basic to Translational Science

BACKGROUNDThoracic aortic aneurysms (TAA) are often found in younger individuals and approximately 20% may be associated with heritable thoracic aortic disease (HTAD). There are some data on genomic biomarkers reflecting inflammation and extracellular matrix remodeling in HTAD. However, data that accurately reflect the corresponding protein changes are scarce. Our aim was to quantify proteins by using targeted proteomics in HTAD patients versus healthy controls (HC). METHODSPatients with Loeys-Dietz syndrome (LDS, n = 8), Marfan syndrome (MFS, n = 11), and Aortic aneurysm, familial thoracic 6 syndrome (AAT6, n = 7) were recruited. For comparison, blood samples were drawn from 16 healthy controls (HC). Plasma samples were analyzed by targeted proteome analysis of 276 proteins using immunoaffinity proteomics. RESULTSSeven proteins were elevated when comparing HTAD to HC, displaying two patterns: i) Oncostatin M (OSM) and Pentraxin-3 (PTX3) were significantly higher in both LDS and MFS, with comparable levels in AAT6, reflecting a generalized increase in HTAD. ii) increased levels of TNF Receptor Superfamily Member 9 (TNFRSF9), Granulysin (GNLY), Glycoprotein 1b-alpha (GP1BA), Vasorin (VASN) and CD5 were restricted to the LDS subgroup and correlated positively with Th17 and platelet counts. CONCLUSIONSThe general increase in OSM and PTX3 in HTAD may reflect early but common mechanisms related to vascular inflammation while the distinct increase in TNFRSF9, GNLY, VASN, GP1BA and CD5 in LDS patients, may reflect involvement of Th17 inflammatory response mechanisms in the progression of TAA. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=163 SRC="FIGDIR/small/624213v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@1234b26org.highwire.dtl.DTLVardef@1ad982org.highwire.dtl.DTLVardef@bdf438org.highwire.dtl.DTLVardef@ec9c67_HPS_FORMAT_FIGEXP M_FIG C_FIG

The pathogenesis of abdominal aortic aneurysm (AAA) formation involves vascular inflammation, thrombosis formation and programmed cell death leading to aortic remodeling. Recent studies have suggested that ferroptosis, an excessive iron-mediated cell death, can regulate cardiovascular diseases, including AAAs. However, the role of ferroptosis in immune cells, like macrophages, and ferroptosis-related genes in AAA formation remains to be deciphered. Single cell-RNA sequencing of human aortic tissue from AAA patients demonstrates significant differences in ferroptosis-related genes compared to control aortic tissue. Using two established murine models of AAA and aortic rupture in C57BL/6 (WT) mice, we observed that treatment with liproxstatin-1, a specific ferroptosis inhibitor, significantly attenuated aortic diameter, pro-inflammatory cytokine production, immune cell infiltration (neutrophils and macrophages), increased smooth muscle cell -actin expression and elastic fiber disruption compared to mice treated with inactivated elastase in both pre-treatment and treatment after a small AAA had already formed. Lipidomic analysis using mass spectrometry shows a significant increase in ceramides and a decrease in intact lipid species levels in murine tissue compared to controls in the chronic AAA model on day 28. Mechanistically, in vitro studies demonstrate that liproxstatin-1 treatment of macrophages mitigated the crosstalk with aortic smooth muscle cells (SMCs) by downregulating MMP2 secretion. Taken together, this study demonstrates that pharmacological inhibition by liproxstatin-1 mitigates macrophage-dependent ferroptosis contributing to inhibition of aortic inflammation and remodeling during AAA formation.

Right ventricular failure (RVF) is a leading cause of morbidity and mortality in multiple cardiovascular diseases, but there are no approved treatments for RVF as therapeutic targets are not clearly defined. Contemporary transcriptomic/proteomic evaluations of RVF are predominately conducted in small animal studies, and data from large animal models are sparse. Moreover, a comparison of the molecular mediators of RVF across species is lacking. Here, we used transcriptomics and proteomics analyses to define the molecular pathways associated with cardiac MRI-derived values of RV hypertrophy, dilation, and dysfunction in pulmonary artery banded (PAB) piglets. Publicly available data from rat monocrotaline-induced RVF and pulmonary arterial hypertension patients with preserved or impaired RV function were used to compare the three species. Transcriptomic and proteomic analyses identified multiple pathways that were associated with RV dysfunction and remodeling in PAB pigs. Surprisingly, disruptions in fatty acid oxidation (FAO) and electron transport chain (ETC) proteins were different across the three species. FAO and ETC proteins and transcripts were mostly downregulated in rats, but were predominately upregulated in PAB pigs, which more closely matched the human data. Thus, the pig PAB metabolic molecular signature was more similar to human RVF than rodents. These data suggest there may be divergent molecular responses of RVF across species, and that pigs more accurately recapitulate the metabolic aspects of human RVF.

BackgroundMyocarditis leads to dilated cardiomyopathy (DCM) with one-third failing to recover normal ejection fraction (EF50%), and there is a critical need for prognostic biomarkers to assess risk of nonrecovery. Cardiac myosin (CM) autoantibodies (AAbs) cross-reactive with the {beta}-adrenergic receptor ({beta}AR) are associated with myocarditis/DCM, but their potential for prognosis and functional relevance is not fully understood. MethodsCM AAbs and myocarditis-derived human monoclonal antibodies (mAbs) were investigated to define pathogenic mechanisms and CM epitopes of nonrecovery. Myocarditis patients who do not recover ejection fraction (EF<50%) by one year were studied in a longitudinal (n=41) cohort. Sera IgG and human mAbs were investigated for autoreactivity with CM and CM peptides by ELISA, protein kinase A (PKA) activation, and transcriptomic analysis in H9c2 heart cell line. ResultsCM AAbs were significantly elevated in nonrecovered compared to recovered patients and correlated with reduced EF (<50%). CM epitopes specific to nonrecovery were identified. Transcriptomic analysis revealed serum IgG and mAb 2C.4 induced fibrosis/apoptosis pathways in vitro similar to isoproterenol treated cells. Sera IgG and 2C.4 activated PKA in an IgG and {beta}AR-dependent manner. Endomyocardial biopsies from myocarditis/DCM revealed IgG+ trichrome+ tissues. ConclusionsCM AAbs were significantly elevated in nonrecovered patients, suggesting novel prognostic relevance. CM AAbs correlated with lower EF, and Ab-induced fibrosis/apoptosis pathways suggested a role for CM AAbs in patients who do not recover and develop irreversible heart failure. Homology between CM and {beta}ARs supports mechanisms related to cross-reactivity of CM AAbs with the {beta}AR, a potential AAb target in nonrecovery.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a leading cause of sudden cardiac death (SCD) in young individuals, yet the mechanisms underlying its pathogenesis, particularly the role of plakophilin-2 (PKP2), remain incompletely understood. This study aimed to elucidate the profile of molecular and metabolic consequences of PKP2 knockdown in a guinea pig model of ARVC. We employed adeno-associated virus serotype 9 (AAV9) to deliver PKP2 shRNA, establishing a model that recapitulates key features of human ARVC, including right ventricular (RV) enlargement, sudden death, and cardiac lipid accumulation. Proteomic analysis revealed significant dysregulation of extracellular matrix (ECM) proteins, PI3K-Akt signaling, and energy metabolism in PKP2-deficient RVs. Metabolomic profiling further highlighted alterations in lipid metabolism and inter-metabolites of TCA cycle, with a notable shift towards fatty acid oxidation. These findings suggest that PKP2 deficiency triggers a cascade of molecular events leading to ECM remodeling, metabolic reconfiguration, and potential mitochondrial dysfunction, which may contribute to the development of ARVC. Our study provides novel insights into the early molecular mechanisms of ARVC and identifies potential therapeutic targets for this underexplored disease.

BackgroundMarfan syndrome (MFS) is a life-threatening heritable connective tissue disorder caused by pathogenic variants in fibrillin-1, characterized by progressive cardiovascular disease. Current medical therapies slow disease progression but do not prevent major complications, underscoring the need for new treatment strategies and unbiased discovery approaches. MethodsWe used a zebrafish model of MFS lacking fibrillin-3 (fbn3-/-), which recapitulates key cardiovascular phenotypes including cardiac stress, valvular defects, arrhythmia, and aortic dilation. To enable sensitive, quantitative assessment of cardiac stress, we generated a novel transgenic zebrafish reporter expressing secreted nanoluciferase under control of the stress-responsive nppb promoter. This reporter was combined with morphological phenotyping and bulbus arteriosus (BA) imaging. We evaluated standard MFS therapies, targeted modulators of TGF-{beta} signaling, and performed an unbiased high-throughput drug screen of over 1 500 clinically approved compounds across multiple developmental treatment windows. Resultsfbn3-/- larvae exhibited markedly elevated nppb activity that correlated with phenotypic severity and peaked during stages of highest mortality. The nanoluciferase reporter provided a [~]1 000-fold dynamic range, substantially outperforming Firefly luciferase-based assays. Pharmacological inhibition of TGF-{beta} signaling produced transient or deleterious effects, while {beta}-blockers, losartan, and allopurinol failed to consistently improve cardiac stress, pericardial edema, or BA dilation. The unbiased high-throughput drug screen identified a small number of primary and secondary hits; however, none demonstrated reproducible phenotypic rescue upon rigorous multi-dose, multi-time window validation. ConclusionsThis study establishes a sensitive zebrafish-based platform for early, quantitative assessment of cardiovascular stress in MFS. Our findings highlight the limited efficacy of current therapies, the context-dependent nature of TGF-{beta} modulation, and the biological complexity underlying MFS pathogenesis. Although no definitive therapeutic candidates were identified, this work lays a robust foundation for expanded unbiased discovery efforts aimed at identifying disease-modifying interventions for MFS.

BackgroundRight ventricular dysfunction (RVD) is a robust predictor of mortality in multiple cardiovascular diseases. Currently, it remains unclear whether the severity of RVD corresponds to distinct cellular and molecular alterations, and this has important implications for defining optimal therapeutic targets. To address this knowledge gap, we performed a multi-omics evaluation of pulmonary artery banded (PAB) pigs with differing degrees of RV compromise. MethodsPAB pigs were stratified into mild and severe RVD groups using an RV ejection fraction cutoff of 35%. RV tissue from control, mild RVD, and severe RVD animals was analyzed using single-nucleus RNA sequencing, mitochondrial and cytoplasmic proteomics, and phosphoproteomics. Histological analyses corroborated multi-omic findings. ResultsCardiac MRI revealed progressive structural and functional alterations in mild and severe RVD pigs. snRNAseq demonstrated that advancing RVD was associated with loss of cardiomyocytes, accumulation of efferocytosis-impaired macrophages, and dysregulated endothelial cells and pericytes. Combined transcriptomic and proteomic analyses showed escalating impairments of complex cardiomyocyte metabolism with worsening RVD. RV microvasculature was compromised with severe RVD as there were alterations in endothelial cell/pericyte genetic regulation, co-localization patterns in RV sections, and ectopic cardiomyocyte HIF1 expression. Analysis of both mitochondrial and global proteostasis revealed greater compromise in mitochondrial proteostasis, including downregulation of mitochondrial proteases, chaperones, and ribosomes. Paradoxically, cytoplasmic ribosomes were upregulated in severe RVD. The predicted kinome and phosphatome were uniquely altered in mild RVD as compared to severe RVD. Finally, integration of multi-omic approaches identified insufficient mitochondrial unfolded protein response, impaired macrophage efferocytosis, and activation of the ribotoxic stress response as potential contributors to severe RVD. ConclusionsOur multi-omic analysis defines the cellular and molecular landscape of progressive RVD and nominates druggable pathways that may promote progressive RV dysfunction. Future studies are needed to determine how targeting these pathways influences RV phenotypes.

ObjectivesWe set out to determine the tricuspid valves propensity to (mal)adapt in disease. BackgroundTricuspid regurgitation (TR) is generally considered secondary to right and/or left ventricular disease without organic failure. Interestingly, we and others have previously shown the mitral valve (mal)adapts in functional mitral regurgitation, which may warrant reconsideration of its functional etiology. Whether the tricuspid valve similarly (mal)adapts is mostly unknown. MethodsWe evaluated the (mal)adaptive response of tricuspid valve anterior leaflets (TVALs) from an ovine model in which over-pacing (19 {+/-} 6 days) induced biventricular heart failure and TR (tachycardia-induced cardiomyopathy, TIC, n=33) and compared findings to those from a control group (n=17). In both groups, we performed proteomics, immunohistochemistry, histology, two-photon microscopy, collagen assays, leaflet thickness and morphology measurements, and biaxial mechanical tests. ResultsWe found metabolically active resident valvular cells in TIC TVALs which expressed activation and turnover markers. In TIC TVALs, we observed a 140% increase in collagen content (p=0.016), increased collagen dispersion regionally (p=0.017), a 130% increase in leaflet area (p=0.002), a 140% increase in thickness (p=0.006), and a 130% increase in radial stiffness (p=0.006). ConclusionsOur data suggest that TVALs (mal)adapt during TIC on all scales. This response is likely initiated by activated valvular cells, resulting in collagen turnover, and ultimately leading to thickening, area increase, and stiffening. Our data motivates future studies on the exact pathways leading to tricuspid (mal)adaptation and pharmacological therapeutic strategies for TR. Condensed AbstractIn most cases, tricuspid regurgitation is presumed to originate from valve extrinsic factors. We challenge this paradigm and hypothesize that the tricuspid valve maladapts, rendering the valve at least partially culpable for its dysfunction. As such, we set out to demonstrate that the tricuspid valve, indeed, maladapts in an ovine model of heart disease. In the anterior leaflets, we found alterations on the protein and cell-level, leading to maladaptation in the form of tissue growth, thickening, and stiffening. Our findings may initially motivate mechanistic pathway studies, and in the future, leaflet-targeted pharmacological therapeutic options for tricuspid regurgitation.

BACKGROUNDThe myocardium in hypoplastic left heart syndrome (HLHS) exhibits immature metabolic programming, impaired mitochondrial quality control, and heightened susceptibility to ischemic and hypoxic injury during palliative surgery. The long non-coding RNA H19 suppresses translation of PTEN-induced putative kinase 1 (PINK1) mRNA and modulates mitochondrial quality control and ischemia/reperfusion injury (IRI) in adult hearts. Whether--and how--H19 regulates mitophagy and IRI in HLHS or in immature animals remains unknown. METHODSWe investigated H19 regulation and its role in mitophagy and ischemia/reperfusion or hypoxia/reoxygenation injury in myocardial tissue from HLHS patients, HLHS-specific induced pluripotent stem cell-derived cardiomyocytes (HLHS-iPSC-CMs), and immature rat hearts. Mechanistic interactions among H19, PINK1/Parkin signaling, and mitophagosome formation were assessed using loss-of-function approaches. RESULTSHLHS myocardium exhibited markedly elevated H19 expression, accompanied by reduced PINK1 and Parkin protein abundance and diminished mitophagosome formation. Similar findings were observed in HLHS-iPSC-CMs exposed to hypoxia/reoxygenation and in immature rat hearts subjected to myocardial IRI. H19 knockdown in HLHS-iPSC-CMs attenuated hypoxia/reoxygenation-induced lactate dehydrogenase release and restored PINK1 and Parkin protein levels. In immature rats, myocardial H19 silencing reduced infarct size, enhanced mitochondrial PINK1 and Parkin expression, and improved post-reperfusion cardiac function for up to 28 days. Conversely, knockdown of PINK1 or Parkin reduced mitophagosome formation and exacerbated functional deterioration during IRI. CONCLUSIONSH19 upregulation impairs PINK1/Parkin-dependent mitophagy and increases susceptibility to ischemic and hypoxic injury in HLHS and the immature heart. These findings identify H19 as a key regulator of mitochondrial quality control and a potential therapeutic target for mitigating IRI in early-life cardiac disease. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=134 SRC="FIGDIR/small/694773v1_ufig1.gif" ALT="Figure 1"> View larger version (50K): org.highwire.dtl.DTLVardef@193defdorg.highwire.dtl.DTLVardef@114ce7forg.highwire.dtl.DTLVardef@1010d05org.highwire.dtl.DTLVardef@1fdeac1_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO C_FIG Novelty and SignificanceO_ST_ABSWhat Is Known?C_ST_ABSO_LIThe myocardium in hypoplastic left heart syndrome (HLHS) exhibits immature metabolic programming, abnormal coronary perfusion, and impaired mitochondrial quality control, rendering it highly susceptible to ischemic and hypoxic injury. C_LIO_LIBoth structural limitations and intrinsic mitochondrial dysfunction contribute to the reduced ischemic tolerance of the HLHS heart, particularly during surgical and hemodynamic stress. C_LIO_LIThe long noncoding RNA H19 regulates mitochondrial quality control and modulates myocardial ischemia/reperfusion injury (IRI) in adult hearts. C_LIO_LIH19 inhibits the binding of the translation initiation factor eIF4A2 to PTEN-induced putative kinase 1 (PINK1) mRNA, thereby suppressing PINK1 protein synthesis and influencing PINK1-dependent mitophagy in adult mice. C_LI What New Information Does This Article Contribute?O_LIThis study identifies robust upregulation of H19 in HLHS myocardium, HLHS-specific induced pluripotent stem cell-derived cardiomyocytes (HLHS-iPSC-CMs) exposed to hypoxia/reoxygenation, and in immature rats subjected to myocardial IRI. C_LIO_LIElevated H19 is associated with suppressed PINK1/Parkin-dependent mitophagy, exacerbated IRI, and adverse post-injury remodeling. C_LIO_LIKnockdown of H19 restores mitochondrial PINK1 and Parkin protein levels, enhances mitophagy, reduces infarct size, and improves long-term recovery of cardiac function--demonstrating a previously unrecognized pathogenic role for H19 in the immature heart under stress. C_LIO_LIKnockdown of PINK1 or Parkin decreases mitophagosomes and exacerbates myocardial IRI in immature rats. C_LI

Although respiratory symptoms are the most prevalent disease manifestation of infection by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), nearly 20% of hospitalized patients are at risk for thromboembolic events. This prothrombotic state is considered a key factor in the increased risk of stroke, which is observed clinically during both acute infection and long after symptoms clear. Here we develop a model of SARS-CoV-2 infection using human-induced pluripotent stem cell-derived endothelial cells (ECs), pericytes (PCs), and smooth muscle cells (SMCs) to recapitulate the vascular pathology associated with SARS-CoV-2 exposure. Our results demonstrate that perivascular cells, particularly SMCs, are a susceptible vascular target for SARS-CoV-2 infection. Utilizing RNA sequencing, we characterize the transcriptomic changes accompanying SARS-CoV-2 infection of SMCs, PCs, and ECs. We observe that infected SMCs shift to a pro-inflammatory state and increase the expression of key mediators of the coagulation cascade. Further, we show human ECs exposed to the secretome of infected SMCs produce hemostatic factors that contribute to vascular dysfunction, despite not being susceptible to direct infection. The findings here recapitulate observations from patient sera in human COVID-19 patients and provide mechanistic insight into the unique vascular implications of SARS-CoV-2 infection at a cellular level.

An abdominal aortic aneurysm (AAA) is a dilation of the aortic wall in the abdomen. Many AAA patients develop intraluminal thrombus (ILT), but the role of ILT in AAA progression and rupture is not well understood. To evaluate ILT in AAAs, we induced AAAs in male C57Bl6/J mice (n=25) via surgical application of topical elastase (5 {micro}L of 5 or 10 mg/mL) to the abdominal aorta below the renal arteries and administration of {beta}-aminopropionitrile (BAPN, 0.2%) drinking water. We collected weekly/biweekly ultrasound images over 56 days. Mice were euthanized and histology images were collected. We semi-quantitatively assessed elastin degradation and inflammation from Movats pentachrome and H&E-stained samples, respectively. Mice with ILT had more significant expansion over the length of the study (beginning at day 14, p<0.05). From histology, ILT samples showed more elastin disorganization and greater inflammation. From scanning electron microscopy, we were able to confirm the presence of layered sheets of fibrin and abnormally shaped red blood cells (polyhedrocytes) within the ILT deposits. In this model, elastase causes aortic injury by degrading elastin fibrils in the aortic wall, reducing the ability of the aorta to contract during high-pressure blood flow. Further damage to the extracellular matrix is likely driven by subsequent inflammation. Here we observed tissue samples with greater acute-on-chronic inflammation were correlated with more elastin damage, and therefore greater aortic expansion. Further, larger aortic expansions were correlated with slower blood flow, likely due to increased cross-sectional area. Thus, increased aortic expansion and damage to the aortic wall may be more likely to create hemodynamic conditions that are conducive to the initiation of ILT deposition: endothelial damage and reduced blood flow. Understanding the relationship between ILT formation, aortic wall degradation, and inflammation could help refine therapeutic strategies for treating AAAs. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=81 SRC="FIGDIR/small/685150v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@f6ba71org.highwire.dtl.DTLVardef@4a8379org.highwire.dtl.DTLVardef@1fd97c1org.highwire.dtl.DTLVardef@1f60400_HPS_FORMAT_FIGEXP M_FIG C_FIG

RationaleAtrial fibrillation (AF) genome-wide association studies (GWAS) identified significant associations for rs1152591 and linked variants in the SYNE2 gene encoding the nesprin-2 protein that connects the nuclear membrane with the cytoskeleton\n\nObjectiveDetermine the effects of the AF-associated rs1152591 and rs1152595, two linked intronic single nucleotide polymorphisms (SNPs), on SYNE2 expression and investigate the mechanisms for their association with AF.\n\nMethods and ResultsRNA sequencing of human left atrial appendage (LAA) tissues indicated that rs1152591 and rs1152595 were significantly associated with the expressions of SYNE21, a short mRNA isoform, without an effect on the expression of the full-length SYNE2 mRNA. SYNE21 mRNA uses an alternative transcription start site and encodes an N-terminal deleted 62 kDa nesprin-21 isoform, which can act as a dominant-negative on nuclear-cytoskeleton connectivity. Western blot and qPCR assays confirmed that AF risk alleles of both SNPs were associated with lower expression of nesprin-21 in human LAA tissues. Reporter gene transfections demonstrated that the risk vs. reference alleles of rs1152591 and rs1152595 had decreased enhancer activity. SYNE2 siRNA knockdown (KD) or nesprin-21 overexpression studies in human stem cell-derived induced cardiomyocytes (iCMs) resulted in ~12.5 % increases in the nuclear area compared to controls (p<0.001). Atomic force microscopy demonstrated that SYNE2 KD or nesprin-21 overexpression led to 57.5% or 33.2% decreases, respectively, in nuclear stiffness compared to controls (p< 0.0001).\n\nConclusionsAF-associated SNPs rs1152591 and rs1152595 downregulate the expression of SYNE21, increasing nuclear-cytoskeletal connectivity and nuclear stiffness. The resulting increase in mechanical stress may play a role in the development of AF.

Marfan syndrome causes a hereditary form of thoracic aortic aneurysms with dilation of the aortic root. Human and animal models suggest a worse phenotype for males compared to females with respect to aneurysm size and risk of dissection. In this study we examine the effects of 17 {beta}-estradiol on aortic dilation and rupture in a Marfan mouse model. Marfan male mice were administered 17 {beta}-estradiol and the growth in aortic root size along with the risk of aortic rupture or dissection with the addition of angiotensin II was measured. Transcriptomic profiling was used to identify enriched pathways from 17 {beta}-estradiol treatment. Aortic smooth muscle cells were then treated with cytokines in order to validate the mechanism of 17 {beta}-estradiol protection. We show that 17 {beta}-estradiol decreased the size and rate of aortic root dilation and improved survival from rupture and dissection after treatment with angiotensin II. The Marfan transcriptome was enriched in inflammatory genes and the addition of 17 {beta}-estradiol modulated a set of genes that function through TNF mediated NF-{kappa}B signaling. These included many proteins known to play a role in the phenotypic shift of aortic smooth muscle cells from a contractile to a more inflammatory-like state such as Vcam-1, Mcp-1, Lgals3, Il-6, Il-1b, and C3. In addition, 17 {beta}-estradiol suppressed the induction of these TNF induced genes in aortic smooth muscle cells in vitro and this effect appears to be NF-{kappa}B dependent. In conclusion, 17 {beta}-estradiol protects against the dilation and rupture of aortic roots in Marfan male mice through the inhibition of TNF -NF-{kappa}B signaling and thus prevents the phenotypic switch of aortic smooth muscle cells from a contractile to an inflammatory state.

Duchenne muscular dystrophy (DMD) is a lethal pediatric striated muscle disease caused by loss of dystrophin for which there is no cure. Cardiomyopathy is the leading cause of death amongst individuals with DMD, and effective therapeutics to treat DMD cardiomyopathy are a major unmet clinical need. This work investigated adeno-associated viral (AAV) gene therapy approaches to treat DMD cardiomyopathy by overexpression of the calcium binding proteins S100A1 and apoptosis repressor with caspase recruitment domains (ARC). Using the severe D2.mdx mouse model of DMD, we identified that S100A1 gene therapy improves the diastolic dysfunction associated with DMD cardiomyopathy, whereas ARC gene therapy prolongs survival. The combination of both S100A1 and ARC in a single bicistronic vector improves the long-term cardiac outcome of D2.mdx mice, development of heart failure caused by micro-dystrophin expression, and exhibits safety via intracoronary delivery in a canine model of DMD. Furthermore, S100A1-ARC gene therapy provides functional benefits when expressed in D2.mdx skeletal muscle. Together, these findings indicate that S100A1-ARC gene therapy represents an effective treatment for DMD cardiomyopathy and may be effective in treating other forms of cardiomyopathy and muscle pathologies. SIGNIFICANCE STATEMENTCardiomyopathy is the leading cause of death amongst individuals with Duchenne muscular dystrophy (DMD). Effective therapeutics to treat DMD cardiomyopathy represent a major unmet clinical need. This work identifies the dual gene therapy approach of S100A1 and ARC as an effective treatment that improves long-term cardiac function and life-expectancy in severe mouse model of DMD. Intracoronary delivery of this AAV-based gene therapy also exhibits safety and evidence of efficacy in dystrophic canines. Furthermore, functional benefits in skeletal muscle are also incurred via S100A1-ARC expression in striated muscle. These findings indicate that S100A1-ARC therapy is an effective treatment for DMD cardiomyopathy whose benefits may be applicable for other forms of cardiac and muscle disease.

Age is a risk factor for aortic aneurysm (AA), and different segments of the aorta exhibit varying susceptibilities to aneurysm. The specific factors that contribute to the higher incidence of AA and its complications with aging remain unclear. Matrix metalloproteinases (MMPs) are elevated in AA. However, the connection between aging, aortic MMP activity, and the increased prevalence of AA and its complications has not been systematically evaluated. This study leveraged MMP-targeted molecular imaging to investigate how aging affects aortic MMP expression and activity, as well as aneurysm development and survival. MethodsAA development and animal survival were monitored for 28 days after Angiotensin (Ang)-II infusion in 8-10-week-old (young) and >51-week-old (old) Apoe-/- mice. Aortic MMP activation was quantified by PET/CT using an MMP-targeted tracer, 64Cu-RYM2, at baseline and 1 week after Ang II infusion. MMP activity and expression were quantified by tissue zymography and quantitative reverse transcription polymerase chain reaction, and compared between different segments of the aorta in young and old animals, and before and after Ang II infusion. ResultsOld animals survival to 28 days was significantly lower than that of young Ang-II-infused Apoe-/- mice (P < 0.05). 64Cu-RYM2 PET/CT showed significantly higher aortic MMP activation before and 1 week after Ang-II infusion in old compared to young Apoe-/-mice. The 64Cu-RYM2 signal was significantly higher in animals that did not survive 28 days than those that did (P < 0.01). MMP activity significantly increased by 4 days after Ang-II infusion, when dissection was found in a subset of Apoe-/- mice; and was significantly higher in the dissected, compared to adjacent, apparently normal, segments of the aorta. MMP activity was also significantly higher in the ascending thoracic aorta of untreated young and old mice, as well as of Ang-II-treated Apoe-/-mice (which was associated with significantly higher Mmp2 gene expression), and of old wild-type mice. ConclusionAging is associated with increased MMP activity along the aorta and worse AA survival. MMP-targeted molecular imaging can inform the aneurysm survival prospects. Selective MMP inhibitors and tracers may help prevent and track aneurysm growth, dissection, and rupture.

1.Severe acute respiratory distress syndrome (ARDS) during SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) infection, manifests as uncontrolled lung inflammation and systemic thrombosis with high mortality. Anti-viral drugs and monoclonal antibodies can reduce COVID-19 severity if administered in the early viremic phase, but treatments for later stage immuno-thrombotic syndrome and long COVID are limited. Serine protease inhibitors (SERPINS) regulate activated proteases during thrombotic, thrombolytic and immune responses. The myxoma poxvirus-derived Serp-1 protein is a secreted immunomodulatory serpin that targets activated coagulation and complement protease pathways as part of a self-defense strategy to combat viral clearance by the innate immune system. When purified and utilized as an anti-immune therapeutic, Serp-1 is effective as an anti-inflammatory drug in multiple animal models of inflammatory lung disease and vasculitis. Here, we describe systemic treatment with purified PEGylated Serp-1 (PEGSerp-1) as a therapy for immuno-thrombotic complications during ARDS. Treatment with PEGSerp-1 in two distinct mouse-adapted SARS-CoV-2 models in C57Bl/6 and BALB/c mice reduced lung and heart inflammation, with improved clinical outcomes. PEGSerp-1 significantly reduced M1 macrophage invasion in the lung and heart by modifying urokinase-type plasminogen activator receptor (uPAR) and complement membrane attack complex (MAC). Sequential changes in urokinase-type plasminogen activator receptor (uPAR) and serpin gene expression were observed in lung and heart with PEGSerp-1 treatment. PEGSerp-1 is a highly effective immune-modulator with therapeutic potential for treatment of severe viral ARDS with additional potential to reduce late SARS-CoV-2 complications related to immune-thrombotic events that persist during long COVID. SignificanceSevere acute respiratory distress syndrome (ARDS) in SARS-CoV-2 infection manifests as uncontrolled tissue inflammation and systemic thrombosis with high mortality. Anti-viral drugs and monoclonal antibodies reduce COVID-19 severity if administered early, but treatments for later stage immuno-thrombosis are limited. Serine protease inhibitors (SERPINS) regulate thrombotic, thrombolytic and complement pathways. We investigate here systemic treatment with purified poxvirus-derived PEGSerp-1 as a therapeutic for immuno-thrombotic complications in viral ARDS. PEGSerp-1 treatment in two mouse-adapted SARS-CoV-2 models (C57Bl/6 and BALB/c) significantly reduced lung and heart inflammation and improved clinical outcomes, with sequential changes in thrombolytic (uPAR) and complement expression. PEGSerp-1 is a highly effective immune-modulator with therapeutic potential for immune-thrombotic complications in severe viral ARDS and has potential benefit for long COVID.

Intracranial aneurysm (IA) is a common cerebrovascular abnormality characterized by localized dilation and wall thinning in intracranial arteries, which can rupture and lead to fatal subarachnoid hemorrhage. Although the pathophysiology of IA remains largely unknown, increasing evidence suggests that genetic susceptibility plays a predominant role. Here, we combined whole exome sequencing and identity-by-descent analyses with functional investigations to identify rare functional variants associated to IA in families with multiple affected subjects. We identified two rare missense variants in the CTSO gene in two large pedigrees. We found that the cysteine-type papain-like cathepsin O (CTSO) encoded by CTSO is expressed in the wall of human IA domes. Stretching of vascular smooth muscle cells (VSMC) induced secretion of CTSO, which acted as an extracellular protease controlling VSMC migration and adhesion to the extracellular matrix. CTSO depletion, as well as expression of the two CTSO variants, which are poorly secreted, increased the amount of fibronectin. In addition, CTSO depletion increased VSMC stiffness, which was reduced by the addition of exogenous CTSO. Collectively, our findings identify CTSO as a potential new player in arterial remodeling, regulating fibronectin deposition and VSMC function, supporting the causal role of rare coding CTSO variants in familial forms of IA.

Bicuspid aortic valve (BAV) is one of the most common congenital heart defects but its genetic basis remains incompletely defined. Extracellular matrix components play key roles in outflow tract (OFT) and valve development, but their contribution to BAV is not fully established. Following the analysis of a cohort of BAV patients, we identified a family harbouring a rare human ELASTIN (ELN) variant (p.Gln691X). To assess its pathogenicity, we generated a zebrafish elna/b double knockout (KO) using an RNAless CRISPR Cas9 strategy to avoid genetic compensation. This mutant exhibited cardiovascular defects including OFT anomalies, reduced stroke volume and dysmorphic aortic valves, highlighting Elastins critical role in cardiac development. We then used this model to test the ELN variant identified in the BAV family. We found that wild-type ELN mRNA was able to restore normal cardiac function and morphology, whereas the variant ELN mRNA failed to do so. This study establishes a robust in vivo model to assess ELN variant pathogenicity and provides evidence linking ELASTIN to BAV, opening new avenues for uncovering the genetic mechanisms underlying BAV.

BackgroundGenetic cardiomyopathies caused by mutations in the dystrophin gene (DMD) are only partially responsive to current pharmacological heart failure treatments, although dilated and arrhythomogenic phenotypes of cardiomyopathy are frequent. ObjectiveIn this study, we tested whether a normalization of Ca2+-handling by forced expression of SERCA2a in cardiomyocytes mitigates heart failure and arrhythmogenesis in a pig model for Duchenne muscular dystrophy (DMD). Methods and resultsMale offspring of pigs lacking DMD exon 52 are characterized by heart failure with reduced ejection fraction (HFrEF, EF 34.5{+/-}1.8% vs. 49.2{+/-}1.0% in control hearts), arrhythmogenesis due to large apical regions of reduced voltage amplitude and sudden cardiac death with a lifespan of usually less than 4 months. Slow antegrade intracoronary infusion of AAV1.SERCA2a (3x1013 virus genomes (vg) per pig) improved left ventricular ejection fraction (EF 47.3{+/-}2.0%, p<0.05) to a similar extent as germline editing of DMD{Delta}52 to DMD{Delta}51-52, inducing a Becker dystrophy (BMD) genotype (EF 46.7{+/-}3.8%). Moreover, AAV.SERCA2a significantly reduced myocardial inflammation and fibrosis and areas of reduced AP amplitude. ConclusionsIn DMD pigs, 3x1013vg/heart of GMP-grade AAV1.SERCA2a sufficed to normalize left ventricular function and improved electrical vulnerability of the heart. Hence, AAV.SERCA2a may serve as a treatment option for DMD cardiomyopathy.

Interleukin-1{beta} (IL-1{beta}) is an apical pro-inflammatory cytokine that has also been shown to negatively modulate cardiac contractility. Whether IL-1{beta} effects on systemic inflammation and cardiac function are intertwined and associated with each other, or whether they are independent of each other, is unknown. An unconventional signaling of the IL-1 receptor type I through the phosphoinositide-3 kinase{gamma} (PI3K{gamma}), at least in part independent of the proinflammatory signaling, has been characterized in inflammation and cancer. We hypothesized that IL-1{beta} would increase the expression of PI3K p110{gamma} in cardiomyocytes, which in turn results in selective induction of p87 co-signaling and cardiac dysfunction through a scaffolding function on phosphodiesterase 3B (PDE3B). Using genetically modified mice, we show that a kinase-independent PI3K p110{gamma} mechanism mediates IL-1-induced cardiac dysfunction. This may have compelling implications for the understanding and treatment of heart failure with reduced ejection fraction.