The Journal of clinical investigation
Lai, YJ;Tsai, FC;Chang, GJ;Chang, SH;Huang, CC;Chen, WJ;Yeh, YH;
PMID: 35775491 | DOI: 10.1172/JCI142548
Atrial fibrosis is an essential contributor to atrial fibrillation (AF). It remains unclear whether atrial endocardial endothelial cells (AEECs) that undergo endothelial-mesenchymal transition (EndMT) are among the sources of atrial fibroblasts. We studied human atria, TGF-β-treated human AEECs, cardiac-specific TGF-β-transgenic mice, and heart failure rabbits to identify the underlying mechanism of EndMT in atrial fibrosis. Using isolated AEECs, we found that miR-181b was induced in TGF-β-treated AEECs, which decreased semaphorin 3A (Sema3A) and increased EndMT markers, and these effects could be reversed by a miR-181b antagomir. Experiments in which Sema3A was increased by a peptide or decreased by a siRNA in AEECs revealed a mechanistic link between Sema3A and LIM-kinase 1/phosphorylated cofilin (LIMK/p-cofilin) signaling and suggested that Sema3A is upstream of LIMK in regulating actin remodeling through p-cofilin. Administration of the miR-181b antagomir or recombinant Sema3A to TGF-β-transgenic mice evoked increased Sema3A, reduced EndMT markers, and significantly decreased atrial fibrosis and AF vulnerability. Our study provides a mechanistic link between the induction of EndMT by TGF-β via miR-181b/Sema3A/LIMK/p-cofilin signaling to atrial fibrosis. Blocking miR-181b and increasing Sema3A are potential strategies for AF therapeutic intervention.
Hypertension (Dallas, Tex. : 1979)
Ritter, ML;Deng, G;Reho, JJ;Deng, Y;Sapouckey, SA;Opichka, MA;Balapattabi, K;Wackman, KK;Brozoski, DT;Lu, KT;Paradee, WJ;Gibson-Corley, KN;Cui, H;Nakagawa, P;Morselli, LL;Sigmund, CD;Grobe, JL;
PMID: 36259376 | DOI: 10.1161/HYPERTENSIONAHA.122.20169
RGS (regulator of G protein signaling) family members catalyze the termination of G protein signaling cascades. Single nucleotide polymorphisms in the RGS2 gene in humans have been linked to hypertension, preeclampsia, and anxiety disorders. Mice deficient for Rgs2 (Rgs2Null) exhibit hypertension, anxiety, and altered adipose development and function.To study cell-specific functions of RGS2, a novel gene-targeted mouse harboring a conditional allele for the Rgs2 gene (Rgs2Flox) was developed. These mice were bred with mice expressing Cre-recombinase via the Agouti-related peptide locus (Agrp-Cre) to cause deletion of Rgs2 from all cells expressing Agrp (Rgs2Agrp-KO), or a novel transgenic mouse expressing Cre-recombinase via the ANG (angiotensin) type 1A receptor (Agtr1a/ AT1A) promoter encoded in a bacterial artificial chromosome (BAC-AT1A-Cre) to delete Rgs2 in all Agtr1a-expressing cells (Rgs2AT1A-KO).Whereas Rgs2Flox, Rgs2Agrp-KO, and BAC-AT1A-Cre mice exhibited normal growth and survival, Rgs2AT1A-KO exhibited pre-weaning lethality. Relative to littermates, Rgs2Agrp-KO exhibited reduced fat gains when maintained on a high fat diet, associated with increased energy expenditure. Similarly, surviving adult Rgs2AT1A-KO mice also exhibited increased energy expenditure. Surprisingly, given the hypertensive phenotype previously reported for Rgs2Null mice and evidence supporting a role for RGS2 in terminating AT1A signaling in various cell types, Rgs2AT1A-KO mice exhibited normal blood pressure, ingestive behaviors, and renal functions, both before and after chronic infusion of ANG (490 ng/kg/min, sc).These results demonstrate the development of a novel mouse with conditional expression of Rgs2 and illustrate the role of Rgs2 within selected cell types for cardiometabolic control.
Proceedings of the National Academy of Sciences of the United States of America
Axelsson Raja, A;Wakimoto, H;DeLaughter, DM;Reichart, D;Gorham, J;Conner, DA;Lun, M;Probst, CK;Sakai, N;Knipe, RS;Montesi, SB;Shea, B;Adam, LP;Leinwand, LA;Wan, W;Choi, ES;Lindberg, EL;Patone, G;Noseda, M;Hübner, N;Seidman, CE;Tager, AM;Seidman, JG;Ho, CY;
PMID: 35787042 | DOI: 10.1073/pnas.2204174119
Myocardial fibrosis is a key pathologic feature of hypertrophic cardiomyopathy (HCM). However, the fibrotic pathways activated by HCM-causing sarcomere protein gene mutations are poorly defined. Because lysophosphatidic acid is a mediator of fibrosis in multiple organs and diseases, we tested the role of the lysophosphatidic acid pathway in HCM. Lysphosphatidic acid receptor 1 (LPAR1), a cell surface receptor, is required for lysophosphatidic acid mediation of fibrosis. We bred HCM mice carrying a pathogenic myosin heavy-chain variant (403+/-) with Lpar1-ablated mice to create mice carrying both genetic changes (403+/- LPAR1 -/-) and assessed development of cardiac hypertrophy and fibrosis. Compared with 403+/- LPAR1WT, 403+/- LPAR1 -/- mice developed significantly less hypertrophy and fibrosis. Single-nucleus RNA sequencing of left ventricular tissue demonstrated that Lpar1 was predominantly expressed by lymphatic endothelial cells (LECs) and cardiac fibroblasts. Lpar1 ablation reduced the population of LECs, confirmed by immunofluorescence staining of the LEC markers Lyve1 and Ccl21a and, by in situ hybridization, for Reln and Ccl21a. Lpar1 ablation also altered the distribution of fibroblast cell states. FB1 and FB2 fibroblasts decreased while FB0 and FB3 fibroblasts increased. Our findings indicate that Lpar1 is expressed predominantly by LECs and fibroblasts in the heart and is required for development of hypertrophy and fibrosis in an HCM mouse model. LPAR1 antagonism, including agents in clinical trials for other fibrotic diseases, may be beneficial for HCM.
Targeting angiotensin type 2 receptors located on pressor neurons in the nucleus of the solitary tract to relieve hypertension in mice
Mohammed, M;Johnson, DN;Wang, LA;Harden, SW;Sheng, W;Spector, EA;Elsaafien, K;Bader, M;Steckelings, UM;Scott, KA;Frazier, CJ;Sumners, C;Krause, EG;de Kloet, AD;
PMID: 33723600 | DOI: 10.1093/cvr/cvab085
These studies evaluate whether angiotensin type-2 receptors (AT2Rs) that are expressed on γ-aminobutyric acid (GABA) neurons in the nucleus of the solitary tract (NTS) represent a novel endogenous blood pressure lowering mechanism. Experiments combined advanced genetic and neuroanatomical techniques, pharmacology, electrophysiology and optogenetics in mice to define the structure and cardiovascular-related function of NTS neurons that contain AT2R. Using mice with Cre-recombinase directed to the AT2R gene, we discovered that optogenetic stimulation of AT2R-expressing neurons in the NTS increases GABA release and blood pressure. To evaluate the role of the receptor, per se, in cardiovascular regulation, we chronically delivered C21, a selective AT2R agonist, into the brains of normotensive mice and found that central AT2R activation reduces GABA-related gene expression and blunts the pressor responses induced by optogenetic excitation of NTS AT2R neurons. Next, using in situ hybridization, we found that the levels of Agtr2 mRNAs in GABAergic NTS neurons rise during experimentally-induced hypertension, and we hypothesized that this increased expression may be exploited to ameliorate the disease. Consistent with this, final experiments revealed that central administration of C21 attenuates hypertension, an effect that is abolished in mice lacking AT2R in GABAergic NTS neurons. These studies unveil novel hindbrain circuits that maintain arterial blood pressure, and reveal a specific population of AT2R that can be engaged to alleviate hypertension. The implication is that these discrete receptors may serve as an access point for activating an endogenous depressor circuit. Hypertension is a widespread health problem and risk factor for cardiovascular disease and stroke. Although treatment options exist, many patients suffer from resistant hypertension, which is associated with enhanced sympathetic drive. Thus, many available therapeutics focus on dampening pressor mechanisms. The present studies take the alternative approach of treating hypertension by exploiting an endogenous depressor mechanism. Published on behalf of the European Society of Cardiology. All rights reserved.
Aherrahrou, R;Lue, D;Perry, RN;Aberra, YT;Khan, MD;Soh, JY;Örd, T;Singha, P;Yang, Q;Gilani, H;Benavente, ED;Wong, D;Hinkle, J;Ma, L;Sheynkman, GM;den Ruijter, HM;Miller, CL;Björkegren, JLM;Kaikkonen, MU;Civelek, M;
PMID: 36597873 | DOI: 10.1161/CIRCRESAHA.122.321586
Coronary artery disease (CAD) is the leading cause of death worldwide. Recent meta-analyses of genome-wide association studies have identified over 175 loci associated with CAD. The majority of these loci are in noncoding regions and are predicted to regulate gene expression. Given that vascular smooth muscle cells (SMCs) play critical roles in the development and progression of CAD, we aimed to identify the subset of the CAD loci associated with the regulation of transcription in distinct SMC phenotypes.We measured gene expression in SMCs isolated from the ascending aortas of 151 heart transplant donors of various genetic ancestries in quiescent or proliferative conditions and calculated the association of their expression and splicing with ~6.3 million imputed single-nucleotide polymorphism markers across the genome.We identified 4910 expression and 4412 splicing quantitative trait loci (sQTLs) representing regions of the genome associated with transcript abundance and splicing. A total of 3660 expression quantitative trait loci (eQTLs) had not been observed in the publicly available Genotype-Tissue Expression dataset. Further, 29 and 880 eQTLs were SMC-specific and sex-biased, respectively. We made these results available for public query on a user-friendly website. To identify the effector transcript(s) regulated by CAD loci, we used 4 distinct colocalization approaches. We identified 84 eQTL and 164 sQTL that colocalized with CAD loci, highlighting the importance of genetic regulation of mRNA splicing as a molecular mechanism for CAD genetic risk. Notably, 20% and 35% of the eQTLs were unique to quiescent or proliferative SMCs, respectively. One CAD locus colocalized with a sex-specific eQTL (TERF2IP), and another locus colocalized with SMC-specific eQTL (ALKBH8). The most significantly associated CAD locus, 9p21, was an sQTL for the long noncoding RNA CDKN2B-AS1, also known as ANRIL, in proliferative SMCs.Collectively, our results provide evidence for the molecular mechanisms of genetic susceptibility to CAD in distinct SMC phenotypes.
Almalki, A;Arjun, S;Bell, R;Yellon, D;
| DOI: 10.1093/eurheartj/ehac544.2918
Background Diabetes clinical trials have shown SGLT inhibition improves cardiovascular outcomes, yet the mechanism is not fully understood. Hyperglycemia is a common finding in diabetic and non-diabetic patients presenting with ACS and is a powerful predictor of prognosis and mortality. The role of hyperglycemia in ischemia-reperfusion injury (IRI) is not fully understood, and whether the Sodium Glucose Co-Transporter 1 (SGLT1) plays a role in infarct augmentation, before and/or after reperfusion, remains to be elucidated. Purpose Investigate if SGLT1 is involved in a glucotoxicity injury during IRI and whether inhibiting SGLT1 with an SGLT1 inhibitor may reduce infarct size. Method RT-PCR and in-situ hybridization (RNAScope) combined with Immunofluorescence integrated co detection with different cell marker techniques were used to detect SGLT1 mRNA expression in Sprague-Dawley whole myocardium and isolated primary cardiomyocytes. An Ex-vivo Langendorff ischemia-reperfusion perfusion model was used to study the effect of high glucose (22mmol) on myocardium at reperfusion. Canagliflozin (CANA) a non-selective SGLT inhibitor (1μmoL/L to block the SGLT1 receptor and SGLT2 and 5nmol/L to block only the SGLT2 receptor) and Mizagliflozin a selective SGLT1 inhibitor (100nmol/L) was introduced following ischemia at two different glucose concentration concentrations at reperfusion and its effect on infarct size measured using triphenyltetrazolium chloride (TTC) staining. Results We showed that SGLT1 is homogenously expressed throughout the myocardium and is particularly evident within the vasculature. we demonstrate that hyperglycemia at reperfusion is injurious to myocardium with an increase of myocardial infarction. Our data reveal that glucose exacerbation of injury appears to be mediated via SGLT1. We have also demonstrated that high-glucose mediated injury in the isolated, perfused heart model is abrogated through the administration of a clinically available mixed SGLT2/SGLT1 inhibitor, canagliflozin, at a dose that inhibits both SGLT2 and SGLT1, but by the SGLT2-selective concentration. Conclusion We have shown that SGLT1 is present in the myocardium. Hyperglycemia appears to augment myocardial infarction and inhibition of SGLT1 attenuates this incre Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): The government of saudi Arabia
Simonson, B;Chaffin, M;Hill, MC;Atwa, O;Guedira, Y;Bhasin, H;Hall, AW;Hayat, S;Baumgart, S;Bedi, KC;Margulies, KB;Klattenhoff, CA;Ellinor, PT;
PMID: 36790929 | DOI: 10.1016/j.celrep.2023.112086
Ischemic cardiomyopathy (ICM) is the leading cause of heart failure worldwide, yet the cellular and molecular signature of this disease is largely unclear. Using single-nucleus RNA sequencing (snRNA-seq) and integrated computational analyses, we profile the transcriptomes of over 99,000 human cardiac nuclei from the non-infarct region of the left ventricle of 7 ICM transplant recipients and 8 non-failing (NF) controls. We find the cellular composition of the ischemic heart is significantly altered, with decreased cardiomyocytes and increased proportions of lymphatic, angiogenic, and arterial endothelial cells in patients with ICM. We show that there is increased LAMININ signaling from endothelial cells to other cell types in ICM compared with NF. Finally, we find that the transcriptional changes that occur in ICM are similar to those in hypertrophic and dilated cardiomyopathies and that the mining of these combined datasets can identify druggable genes that could be used to target end-stage heart failure.
Pearce, L;He, D;Davidson, SM;Yellon, DM;
| DOI: 10.1161/circ.146.suppl_1.11926
Introduction: Myocardial infarction causes several types of injury to the myocardium including lethal cell injury and ‘no-reflow’ (NRF) /microvascular obstruction (MVO). Nonselective Rho Kinase (ROCK1/2) inhibitors such as Fasudil, ameliorate myocardial ischemia/reperfusion (I/R) injury but cause unwanted hypotension. Selective ROCK2 inhibitors (e.g.: KD025) are safe in clinical trials without causing haemodynamic compromise, however they have not been investigated in myocardial I/R. ROCK inhibitors prevent vascular smooth muscle cell (VSMC) contraction; such VSMC contraction/coronary spasm being features of ‘no-reflow’ (NRF) and microvascular obstruction (MVO). At present, there are limited therapies to improve ischemic MVO outcomes, and prognosis is poor. Hypothesis: Using a rat model, we hypothesised that, i) ROCK2 mRNA is expressed in myocardium and coronary vasculature and ii) The selective ROCK2 inhibitor KD025, would reduce infarct size (IS%) and NRF% (MVO) following I/R. Methods: RNA scope in-situ hybridisation was performed with a fluorescent, multiplex assay for ROCK1/2 & VSMC mRNA in myocardium and coronary vasculature. Male SD rats underwent in-vivo myocardial infarction with 30min ischemia, 180min reperfusion. 15min prior to reperfusion, the ROCK inhibitors Fasudil and KD025 or vehicle (DMSO) were administered i.p. For IS%, myocardium was stained with TTC, and regions not perfused with 1.5% Thioflavin S (NRF%), were visualised under UV light. Results: RNAscope confirmed the presence of ROCK2 mRNA within myocardium and VSMC of coronary arteries. Fasudil (10mg/kg) vs control significantly reduced regional IS% (30.3±4.4 vs52.9±3.8,p=0.02, n=15) and area of NRF% (12.4±2.8 vs28.6±2.2, p=0.001, n=15). However, there was significant hypotension;- Mean BP (mmHg) (72±3.9) vs control (84±2.3, p=0.007). KD025 (100mg/kg) did not reduce IS%, but significantly reduced the area of NRF% vs control (18.4±2.8 vs28.6±2.2,p=0.02, n=14) without hypotensive effect. Conclusions: Our results suggest that ROCK2 may be a prospective target in the management of coronary circulation reperfusion injury and ischemic MVO.
bioRxiv : the preprint server for biology
Kim, HJ;Cheng, P;Travisano, S;Weldy, C;Monteiro, JOP;Kundu, R;Nguyen, T;Sharma, D;Shi, H;Lin, Y;Liu, B;Haldar, S;Jackson, S;Quertermous, T;
PMID: 36747745 | DOI: 10.1101/2023.01.26.525789
Platelet derived growth factor (PDGF) signaling has been extensively studied in the context of vascular disease, but the genetics of this pathway remain to be established. Genome wide association studies (GWAS) for coronary artery disease (CAD) have identified a risk locus at 11q22.3, and we have verified with fine mapping approaches that the regulatory variant rs2019090 and PDGFD represent the functional variant and putative functional gene. Further, FOXC1/C2 transcription factor (TF) binding at rs2019090 was found to promote PDGFD transcription through the CAD promoting allele. Employing a constitutive Pdgfd knockout allele along with SMC lineage tracing in a male atherosclerosis mouse model we mapped single cell transcriptomic, cell state, and lesion anatomical changes associated with gene loss. These studies revealed that Pdgfd promotes expansion, migration, and transition of SMC lineage cells to the chondromyocyte phenotype and vascular calcification. This is in contrast to protective CAD genes TCF21 , ZEB2 , and SMAD3 which we have shown to promote the fibroblast-like cell transition or perturb the pattern or extent of transition to the chondromyocyte phenotype. Further, Pdgfd expressing fibroblasts and pericytes exhibited greater expression of chemokines and leukocyte adhesion molecules, consistent with observed increased macrophage recruitment to the plaque. Despite these changes there was no effect of Pdgfd deletion on SMC contribution to the fibrous cap or overall lesion burden. These findings suggest that PDGFD mediates CAD risk through promoting SMC expansion and migration, in conjunction with deleterious phenotypic changes, and through promoting an inflammatory response that is primarily focused in the adventitia where it contributes to leukocyte trafficking to the diseased vessel wall.
Arteriosclerosis, thrombosis, and vascular biology
Chou, EL;Chaffin, M;Simonson, B;Pirruccello, JP;Akkad, AD;Nekoui, M;Lino Cardenas, CL;Bedi, KC;Nash, C;Juric, D;Stone, JR;Isselbacher, EM;Margulies, KB;Klattenhoff, C;Ellinor, PT;Lindsay, ME;
PMID: 36172868 | DOI: 10.1161/ATVBAHA.122.317953
Mural cells in ascending aortic aneurysms undergo phenotypic changes that promote extracellular matrix destruction and structural weakening. To explore this biology, we analyzed the transcriptional features of thoracic aortic tissue.Single-nuclear RNA sequencing was performed on 13 samples from human donors, 6 with thoracic aortic aneurysm, and 7 without aneurysm. Individual transcriptomes were then clustered based on transcriptional profiles. Clusters were used for between-disease differential gene expression analyses, subcluster analysis, and analyzed for intersection with genetic aortic trait data.We sequenced 71 689 nuclei from human thoracic aortas and identified 14 clusters, aligning with 11 cell types, predominantly vascular smooth muscle cells (VSMCs) consistent with aortic histology. With unbiased methodology, we found 7 vascular smooth muscle cell and 6 fibroblast subclusters. Differentially expressed genes analysis revealed a vascular smooth muscle cell group accounting for the majority of differential gene expression. Fibroblast populations in aneurysm exhibit distinct behavior with almost complete disappearance of quiescent fibroblasts. Differentially expressed genes were used to prioritize genes at aortic diameter and distensibility genome-wide association study loci highlighting the genes JUN, LTBP4 (latent transforming growth factor beta-binding protein 1), and IL34 (interleukin 34) in fibroblasts, ENTPD1, PDLIM5 (PDZ and LIM domain 5), ACTN4 (alpha-actinin-4), and GLRX in vascular smooth muscle cells, as well as LRP1 in macrophage populations.Using nuclear RNA sequencing, we describe the cellular diversity of healthy and aneurysmal human ascending aorta. Sporadic aortic aneurysm is characterized by differential gene expression within known cellular classes rather than by the appearance of novel cellular forms. Single-nuclear RNA sequencing of aortic tissue can be used to prioritize genes at aortic trait loci.
Nguyen, PD;Gooijers, I;Campostrini, G;Verkerk, AO;Honkoop, H;Bouwman, M;de Bakker, DEM;Koopmans, T;Vink, A;Lamers, GEM;Shakked, A;Mars, J;Mulder, AA;Chocron, S;Bartscherer, K;Tzahor, E;Mummery, CL;de Boer, TP;Bellin, M;Bakkers, J;
PMID: 37200435 | DOI: 10.1126/science.abo6718
Zebrafish hearts can regenerate by replacing damaged tissue with new cardiomyocytes. Although the steps leading up to the proliferation of surviving cardiomyocytes have been extensively studied, little is known about the mechanisms that control proliferation and redifferentiation to a mature state. We found that the cardiac dyad, a structure that regulates calcium handling and excitation-contraction coupling, played a key role in the redifferentiation process. A component of the cardiac dyad called leucine-rich repeat-containing 10 (Lrrc10) acted as a negative regulator of proliferation, prevented cardiomegaly, and induced redifferentiation. We found that its function was conserved in mammalian cardiomyocytes. This study highlights the importance of the underlying mechanisms required for heart regeneration and their application to the generation of fully functional cardiomyocytes.
Horii, Y;Matsuda, S;Toyota, C;Morinaga, T;Nakaya, T;Tsuchiya, S;Ohmuraya, M;Hironaka, T;Yoshiki, R;Kasai, K;Yamauchi, Y;Takizawa, N;Nagasaka, A;Tanaka, A;Kosako, H;Nakaya, M;
PMID: 36754961 | DOI: 10.1038/s41467-023-36189-6
Myofibroblasts cause tissue fibrosis by producing extracellular matrix proteins, such as collagens. Humoral factors like TGF-β, and matrix stiffness are important for collagen production by myofibroblasts. However, the molecular mechanisms regulating their ability to produce collagen remain poorly characterised. Here, we show that vestigial-like family member 3 (VGLL3) is specifically expressed in myofibroblasts from mouse and human fibrotic hearts and promotes collagen production. Further, substrate stiffness triggers VGLL3 translocation into the nucleus through the integrin β1-Rho-actin pathway. In the nucleus, VGLL3 undergoes liquid-liquid phase separation via its low-complexity domain and is incorporated into non-paraspeckle NONO condensates containing EWS RNA-binding protein 1 (EWSR1). VGLL3 binds EWSR1 and suppresses miR-29b, which targets collagen mRNA. Consistently, cardiac fibrosis after myocardial infarction is significantly attenuated in Vgll3-deficient mice, with increased miR-29b expression. Overall, our results reveal an unrecognised VGLL3-mediated pathway that controls myofibroblasts' collagen production, representing a novel therapeutic target for tissue fibrosis.