Academic Appointments

Current Research and Scholarly Interests

Cardiovascular developmental biology

2018-19 Courses

Stanford Advisees

Graduate and Fellowship Programs

  • Biology (School of Humanities and Sciences) (Phd Program)

All Publications

  • A Unique Collateral Artery Development Program Promotes Neonatal Heart Regeneration. Cell Das, S., Goldstone, A. B., Wang, H., Farry, J., D'Amato, G., Paulsen, M. J., Eskandari, A., Hironaka, C. E., Phansalkar, R., Sharma, B., Rhee, S., Shamskhou, E. A., Agalliu, D., de Jesus Perez, V., Woo, Y. J., Red-Horse, K. 2019


    Collateral arteries are an uncommon vessel subtype that can provide alternate blood flow to preserve tissue following vascular occlusion. Some patients with heart disease develop collateral coronary arteries, and this correlates with increased survival. However, it is not known how these collaterals develop or how to stimulate them. We demonstrate that neonatal mouse hearts use a novel mechanism to build collateral arteries in response to injury. Arterial endothelial cells (ECs) migrated away from arteries along existing capillaries and reassembled into collateral arteries, which we termed "artery reassembly". Artery ECs expressed CXCR4, and following injury, capillary ECs induced its ligand, CXCL12. CXCL12 or CXCR4 deletion impaired collateral artery formation and neonatal heart regeneration. Artery reassembly was nearly absent in adults but was induced by exogenous CXCL12. Thus, understanding neonatal regenerative mechanisms can identify pathways that restore these processes in adults and identify potentially translatable therapeutic strategies for ischemic heart disease.

    View details for DOI 10.1016/j.cell.2018.12.023

    View details for PubMedID 30686582

  • Characterization of brain dysfunction induced by bacterial lipopeptides that alter neuronal activity and network in rodent brains. The Journal of neuroscience : the official journal of the Society for Neuroscience Kim, K., Zamaleeva, A. I., Woo Lee, Y., Ahmed, M. R., Kim, E., Lee, H., Raveendra Pothineni, V., Tao, J., Rhee, S., Jayakumar, M., Inayathullah, M., Sivanesan, S., Red-Horse, K., Palmer, T. D., Park, J., Madison, D. V., Lee, H., Rajadas, J. 2018


    The immunopathological states of the brain induced by bacterial lipoproteins have been well-characterized by employing biochemical and histological assays. However, these studies have limitations in determining functional states of damaged brains involving aberrant synaptic activity and network, which makes it difficult to diagnose brain disorders during bacterial infection. To address this, we investigated the effect of Pam3CSK4 (PAM), a synthetic bacterial lipopeptide, on synaptic dysfunction of female mice brains and cultured neurons in parallel. Our functional brain imaging using PET with [18F]-FDG and [18F]-FMZ revealed the brain dysfunction induced by PAM is closely aligned to disruption of neurotransmitter-related neuronal activity and functional correlation in the region of the limbic system rather than to decrease of metabolic activity of neurons in the injection area. This finding was verified by in vivo tissue experiments that analyzed synaptic and dendritic alterations in the regions where PET imaging showed abnormal neuronal activity and network. Recording of synaptic activity also revealed that PAM reorganized synaptic distribution and decreased synaptic plasticity in hippocampus. Further study using in vitro neuron cultures demonstrated that PAM decreased the number of presynapses and the frequency of mEPSC, which suggests PAM disrupts neuronal function by damaging presynapses exclusively. We also showed PAM caused aggregation of synapses around dendrites, which may have caused no significant change in expression level of synaptic proteins while synaptic number and function was impaired by PAM. New findings of this study could provide a useful guide for diagnosis and treatment of brain disorders specific to bacterial infection.SIGNIFICANCE STATEMENTIt is challenging to diagnose brain disorders caused by bacterial infection because neural damage induced by bacterial products involves non-specific neurological symptoms, which is rarely detected by laboratory tests with low spatiotemporal resolution. To better understand brain pathology, it is essential to detect functional abnormalities of brain over time. To this end, we investigated characteristic patterns of altered neuronal integrity and functional correlation between various regions in mice brains injected with bacterial lipopeptides by using PET with a goal to apply new findings to diagnosis of brain disorder specific to bacterial infection. In addition, we analyzed altered synaptic density and function using both in vivo and in vitro experimental models to understand how bacterial lipopeptides impair brain function and network.

    View details for DOI 10.1523/JNEUROSCI.0825-17.2018

    View details for PubMedID 30381406

  • Large-Scale Single-Cell RNA-Seq Reveals Molecular Signatures of Heterogeneous Populations of Human Induced Pluripotent Stem Cell-Derived Endothelial Cells. Circulation research Paik, D. T., Tian, L., Lee, J., Sayed, N., Chen, I. Y., Rhee, S., Rhee, J., Kim, Y., Wirka, R. C., Buikema, J. W., Wu, S. M., Red-Horse, K., Quertermous, T., Wu, J. C. 2018


    Rationale: Human induced pluripotent stem cell-derived endothelial cells (iPSC-ECs) have risen as a useful tool in cardiovascular research, offering a wide gamut of translational and clinical applications. However, inefficiency of the currently available iPSC-EC differentiation protocol and underlying heterogeneity of derived iPSC-ECs remain as major limitations of iPSC-EC technology. Objective: Here we performed droplet-based single-cell RNA-sequencing (scRNA-seq) of the human iPSCs following iPSC-EC differentiation. Droplet-based scRNA-seq enables analysis of thousands of cells in parallel, allowing comprehensive analysis of transcriptional heterogeneity. Methods and Results: Bona fide iPSC-EC cluster was identified by scRNA-seq, which expressed high levels of endothelial-specific genes. iPSC-ECs, sorted by CD144 antibody-conjugated magnetic sorting, exhibited standard endothelial morphology and function including tube formation, response to inflammatory signals, and production of nitric oxide. Non-endothelial cell populations resulting from the differentiation protocol were identified, which included immature and atrial-like cardiomyocytes, hepatic-like cells, and vascular smooth muscle cells. Furthermore, scRNA-seq analysis of purified iPSC-ECs revealed transcriptional heterogeneity with four major subpopulations, marked by robust enrichment of CLDN5, APLNR, GJA5, and ESM1 genes respectively. Conclusions: Massively parallel, droplet-based scRNA-seq allowed meticulous analysis of thousands of human iPSCs subjected to iPSC-EC differentiation. Results showed inefficiency of the differentiation technique, which can be improved with further studies based on identification of molecular signatures that inhibit expansion of non-endothelial cell types. Subtypes of bona fide human iPSC-ECs were also identified, allowing us to sort for iPSC-ECs with specific biological function and identity.

    View details for DOI 10.1161/CIRCRESAHA.118.312913

    View details for PubMedID 29986945

  • Endothelial deletion of Ino80 disrupts coronary angiogenesis and causes congenital heart disease. Nature communications Rhee, S., Chung, J. I., King, D. A., D'amato, G., Paik, D. T., Duan, A., Chang, A., Nagelberg, D., Sharma, B., Jeong, Y., Diehn, M., Wu, J. C., Morrison, A. J., Red-Horse, K. 2018; 9 (1): 368


    During development, the formation of a mature, well-functioning heart requires transformation of the ventricular wall from a loose trabecular network into a dense compact myocardium at mid-gestation. Failure to compact is associated in humans with congenital diseases such as left ventricular non-compaction (LVNC). The mechanisms regulating myocardial compaction are however still poorly understood. Here, we show that deletion of the Ino80 chromatin remodeler in vascular endothelial cells prevents ventricular compaction in the developing mouse heart. This correlates with defective coronary vascularization, and specific deletion of Ino80 in the two major coronary progenitor tissues-sinus venosus and endocardium-causes intermediate phenotypes. In vitro, endothelial cells promote myocardial expansion independently of blood flow in an Ino80-dependent manner. Ino80 deletion increases the expression of E2F-activated genes and endothelial cell S-phase occupancy. Thus, Ino80 is essential for coronary angiogenesis and allows coronary vessels to support proper compaction of the heart wall.

    View details for DOI 10.1038/s41467-017-02796-3

    View details for PubMedID 29371594

  • Single-cell analysis of early progenitor cells that build coronary arteries. Nature Su, T., Stanley, G., Sinha, R., D'Amato, G., Das, S., Rhee, S., Chang, A. H., Poduri, A., Raftrey, B., Dinh, T. T., Roper, W. A., Li, G., Quinn, K. E., Caron, K. M., Wu, S., Miquerol, L., Butcher, E. C., Weissman, I., Quake, S., Red-Horse, K. 2018


    Arteries and veins are specified by antagonistic transcriptional programs. However, during development and regeneration, new arteries can arise from pre-existing veins through a poorly understood process of cell fate conversion. Here, using single-cell RNA sequencing and mouse genetics, we show that vein cells of the developing heart undergo an early cell fate switch to create a pre-artery population that subsequently builds coronary arteries. Vein cells underwent a gradual and simultaneous switch from venous to arterial fate before a subset of cells crossed a transcriptional threshold into the pre-artery state. Before the onset of coronary blood flow, pre-artery cells appeared in the immature vessel plexus, expressed mature artery markers, and decreased cell cycling. The vein-specifying transcription factor COUP-TF2 (also known as NR2F2) prevented plexus cells from overcoming the pre-artery threshold by inducing cell cycle genes. Thus, vein-derived coronary arteries are built by pre-artery cells that can differentiate independently of blood flow upon the release of inhibition mediated by COUP-TF2 and cell cycle factors.

    View details for DOI 10.1038/s41586-018-0288-7

    View details for PubMedID 29973725

  • DACH1 stimulates shear stress-guided endothelial cell migration and coronary artery growth through the CXCL12-CXCR4 signaling axis GENES & DEVELOPMENT Chang, A. H., Raftrey, B. C., D'Amato, G., Surya, V. N., Poduri, A., Chen, H. I., Goldstone, A. B., Woo, J., Fuller, G. G., Dunn, A. R., Red-Horse, K. 2017; 31 (13): 1308–24


    Sufficient blood flow to tissues relies on arterial blood vessels, but the mechanisms regulating their development are poorly understood. Many arteries, including coronary arteries of the heart, form through remodeling of an immature vascular plexus in a process triggered and shaped by blood flow. However, little is known about how cues from fluid shear stress are translated into responses that pattern artery development. Here, we show that mice lacking endothelial Dach1 had small coronary arteries, decreased endothelial cell polarization, and reduced expression of the chemokine Cxcl12 Under shear stress in culture, Dach1 overexpression stimulated endothelial cell polarization and migration against flow, which was reversed upon CXCL12/CXCR4 inhibition. In vivo, DACH1 was expressed during early arteriogenesis but was down in mature arteries. Mature artery-type shear stress (high, uniform laminar) specifically down-regulated DACH1, while the remodeling artery-type flow (low, variable) maintained DACH1 expression. Together, our data support a model in which DACH1 stimulates coronary artery growth by activating Cxcl12 expression and endothelial cell migration against blood flow into developing arteries. This activity is suppressed once arteries reach a mature morphology and acquire high, laminar flow that down-regulates DACH1. Thus, we identified a mechanism by which blood flow quality balances artery growth and maturation.

    View details for DOI 10.1101/gad.301549.117

    View details for Web of Science ID 000407611300003

    View details for PubMedID 28779009

    View details for PubMedCentralID PMC5580653

  • Coronary Artery Development: Progenitor Cells and Differentiation Pathways. Annual review of physiology Sharma, B., Chang, A., Red-Horse, K. 2017; 79: 1-19


    Coronary artery disease (CAD) is the number one cause of death worldwide and involves the accumulation of plaques within the artery wall that can occlude blood flow to the heart and cause myocardial infarction. The high mortality associated with CAD makes the development of medical interventions that repair and replace diseased arteries a high priority for the cardiovascular research community. Advancements in arterial regenerative medicine could benefit from a detailed understanding of coronary artery development during embryogenesis and of how these pathways might be reignited during disease. Recent research has advanced our knowledge on how the coronary vasculature is built and revealed unexpected features of progenitor cell deployment that may have implications for organogenesis in general. Here, we highlight these recent findings and discuss how they set the stage to interrogate developmental pathways during injury and disease.

    View details for DOI 10.1146/annurev-physiol-022516-033953

    View details for PubMedID 27959616

  • Cellular plasticity in cardiovascular development and disease. Developmental dynamics Das, S., Red-Horse, K. 2017


    Knowledge on cellular differentiation pathways is critical to understanding organ development, homeostasis, and disease. Studying cell differentiation and cell fate restrictions in these contexts can be done through lineage tracing experiments, which entail permanent labeling of a cell and all its progeny. Recent lineage experiments within the cardiovascular system have uncovered unexpected findings on cellular origins during organogenesis and cell plasticity during disease. For example, there is increasing evidence that multiple progenitor sources exist for a single cell type, and that cells have remarkable expansive capacities under disease settings. Here, we summarize some recent findings in the cardiovascular system and highlight where there is evidence that the underlying concepts are a widespread phenomenon used by other organ systems. Developmental Dynamics 246:328-335, 2017. © 2016 Wiley Periodicals, Inc.

    View details for DOI 10.1002/dvdy.24486

    View details for PubMedID 28097739

  • Alternative Progenitor Cells Compensate to Rebuild the Coronary Vasculature in Elabela- and Apj-Deficient Hearts. Developmental cell Sharma, B., Ho, L., Ford, G. H., Chen, H. I., Goldstone, A. B., Woo, Y. J., Quertermous, T., Reversade, B., Red-Horse, K. 2017


    Organogenesis during embryonic development occurs through the differentiation of progenitor cells. This process is extraordinarily accurate, but the mechanisms ensuring high fidelity are poorly understood. Coronary vessels of the mouse heart derive from at least two progenitor pools, the sinus venosus and endocardium. We find that the ELABELA (ELA)-APJ signaling axis is only required for sinus venosus-derived progenitors. Because they do not depend on ELA-APJ, endocardial progenitors are able to expand and compensate for faulty sinus venosus development in Apj mutants, leading to normal adult heart function. An upregulation of endocardial SOX17 accompanied compensation in Apj mutants, which was also seen in Ccbe1 knockouts, indicating that the endocardium is activated in multiple cases where sinus venosus angiogenesis is stunted. Our data demonstrate that by diversifying their responsivity to growth cues, distinct coronary progenitor pools are able to compensate for each other during coronary development, thereby providing robustness to organ development.

    View details for DOI 10.1016/j.devcel.2017.08.008

    View details for PubMedID 28890073

  • Endothelial cells respond to the direction of mechanical stimuli through SMAD signaling to regulate coronary artery size. Development (Cambridge, England) Poduri, A., Chang, A. H., Raftrey, B., Rhee, S., Van, M., Red-Horse, K. 2017; 144 (18): 3241–52


    How mechanotransduction intersects with chemical and transcriptional factors to shape organogenesis is an important question in developmental biology. This is particularly relevant to the cardiovascular system, which uses mechanical signals from flowing blood to stimulate cytoskeletal and transcriptional responses that form a highly efficient vascular network. Using this system, artery size and structure are tightly regulated, but the underlying mechanisms are poorly understood. Here, we demonstrate that deletion of Smad4 increased the diameter of coronary arteries during mouse embryonic development, a phenotype that followed the initiation of blood flow. At the same time, the BMP signal transducers SMAD1/5/8 were activated in developing coronary arteries. In a culture model of blood flow-induced shear stress, human coronary artery endothelial cells failed to align when either BMPs were inhibited or SMAD4 was depleted. In contrast to control cells, SMAD4-deficient cells did not migrate against the direction of shear stress and increased proliferation rates specifically under flow. Similar alterations were seen in coronary arteries in vivo Thus, endothelial cells perceive the direction of blood flow and respond through SMAD signaling to regulate artery size.

    View details for DOI 10.1242/dev.150904

    View details for PubMedID 28760815

    View details for PubMedCentralID PMC5612251

  • Endothelial APLNR regulates tissue fatty acid uptake and is essential for apelin's glucose-lowering effects. Science translational medicine Hwangbo, C., Wu, J., Papangeli, I., Adachi, T., Sharma, B., Park, S., Zhao, L., Ju, H., Go, G. W., Cui, G., Inayathullah, M., Job, J. K., Rajadas, J., Kwei, S. L., Li, M. O., Morrison, A. R., Quertermous, T., Mani, A., Red-Horse, K., Chun, H. J. 2017; 9 (407)


    Treatment of type 2 diabetes mellitus continues to pose an important clinical challenge, with most existing therapies lacking demonstrable ability to improve cardiovascular outcomes. The atheroprotective peptide apelin (APLN) enhances glucose utilization and improves insulin sensitivity. However, the mechanism of these effects remains poorly defined. We demonstrate that the expression of APLNR (APJ/AGTRL1), the only known receptor for apelin, is predominantly restricted to the endothelial cells (ECs) of multiple adult metabolic organs, including skeletal muscle and adipose tissue. Conditional endothelial-specific deletion of Aplnr (Aplnr(ECKO) ) resulted in markedly impaired glucose utilization and abrogation of apelin-induced glucose lowering. Furthermore, we identified inactivation of Forkhead box protein O1 (FOXO1) and inhibition of endothelial expression of fatty acid (FA) binding protein 4 (FABP4) as key downstream signaling targets of apelin/APLNR signaling. Both the Apln(-/-) and Aplnr(ECKO) mice demonstrated increased endothelial FABP4 expression and excess tissue FA accumulation, whereas concurrent endothelial Foxo1 deletion or pharmacologic FABP4 inhibition rescued the excess FA accumulation phenotype of the Apln(-/-) mice. The impaired glucose utilization in the Aplnr(ECKO) mice was associated with excess FA accumulation in the skeletal muscle. Treatment of these mice with an FABP4 inhibitor abrogated these metabolic phenotypes. These findings provide mechanistic insights that could greatly expand the therapeutic repertoire for type 2 diabetes and related metabolic disorders.

    View details for DOI 10.1126/scitranslmed.aad4000

    View details for PubMedID 28904225

  • MicroRNA 139-5p coordinates APLNR-CXCR4 crosstalk during vascular maturation NATURE COMMUNICATIONS Papangeli, I., Kim, J., Maier, I., Park, S., Lee, A., Kang, Y., Tanaka, K., Khan, O. F., Ju, H., Kojima, Y., Red-Horse, K., Anderson, D. G., Siekmann, A. F., Chun, H. J. 2016; 7


    G protein-coupled receptor (GPCR) signalling, including that involving apelin (APLN) and its receptor APLNR, is known to be important in vascular development. How this ligand-receptor pair regulates the downstream signalling cascades in this context remains poorly understood. Here, we show that mice with Apln, Aplnr or endothelial-specific Aplnr deletion develop profound retinal vascular defects, which are at least in part due to dysregulated increase in endothelial CXCR4 expression. Endothelial CXCR4 is negatively regulated by miR-139-5p, whose transcription is in turn induced by laminar flow and APLN/APLNR signalling. Inhibition of miR-139-5p in vivo partially phenocopies the retinal vascular defects of APLN/APLNR deficiency. Pharmacological inhibition of CXCR4 signalling or augmentation of the miR-139-5p-CXCR4 axis can ameliorate the vascular phenotype of APLN/APLNR deficient state. Overall, we identify an important microRNA-mediated GPCR crosstalk, which plays a key role in vascular development.

    View details for DOI 10.1038/ncomms11268

    View details for Web of Science ID 000373830000001

    View details for PubMedID 27068353

    View details for PubMedCentralID PMC4832062

  • Pericytes are progenitors for coronary artery smooth muscle. eLife Volz, K. S., Jacobs, A. H., Chen, H. I., Poduri, A., McKay, A. S., Riordan, D. P., Kofler, N., Kitajewski, J., Weissman, I., Red-Horse, K. 2015; 4


    Epicardial cells on the heart's surface give rise to coronary artery smooth muscle cells (caSMCs) located deep in the myocardium. However, the differentiation steps between epicardial cells and caSMCs are unknown as are the final maturation signals at coronary arteries. Here, we use clonal analysis and lineage tracing to show that caSMCs derive from pericytes, mural cells associated with microvessels, and that these cells are present in adults. During development following the onset of blood flow, pericytes at arterial remodeling sites upregulate Notch3 while endothelial cells express Jagged-1. Deletion of Notch3 disrupts caSMC differentiation. Our data support a model wherein epicardial-derived pericytes populate the entire coronary microvasculature, but differentiate into caSMCs at arterial remodeling zones in response to Notch signaling. Our data are the first demonstration that pericytes are progenitors for smooth muscle, and their presence in adult hearts reveals a new potential cell type for targeting during cardiovascular disease.

    View details for DOI 10.7554/eLife.10036

    View details for PubMedID 26479710

    View details for PubMedCentralID PMC4728130

  • Genetic targeting of sprouting angiogenesis using Apln-CreER. Nature communications Liu, Q., Hu, T., He, L., Huang, X., Tian, X., Zhang, H., He, L., Pu, W., Zhang, L., Sun, H., Fang, J., Yu, Y., Duan, S., Hu, C., Hui, L., Zhang, H., Quertermous, T., Xu, Q., Red-Horse, K., Wythe, J. D., Zhou, B. 2015; 6: 6020-?

    View details for DOI 10.1038/ncomms7020

    View details for PubMedID 25597280

  • The sinus venosus contributes to coronary vasculature through VEGFC-stimulated angiogenesis DEVELOPMENT Chen, H. I., Sharma, B., Akerberg, B. N., Numi, H. J., Kivela, R., Saharinen, P., Aghajanian, H., McKay, A. S., Bogard, P. E., Chang, A. H., Jacobs, A. H., Epstein, J. A., Stankunas, K., Alitalo, K., Red-Horse, K. 2014; 141 (23): 4500-4512


    Identifying coronary artery progenitors and their developmental pathways could inspire novel regenerative treatments for heart disease. Multiple sources of coronary vessels have been proposed, including the sinus venosus (SV), endocardium and proepicardium, but their relative contributions to the coronary circulation and the molecular mechanisms regulating their development are poorly understood. We created an ApjCreER mouse line as a lineage-tracing tool to map SV-derived vessels onto the heart and compared the resulting lineage pattern with endocardial and proepicardial contributions to the coronary circulation. The data showed a striking compartmentalization to coronary development. ApjCreER-traced vessels contributed to a large number of arteries, capillaries and veins on the dorsal and lateral sides of the heart. By contrast, untraced vessels predominated in the midline of the ventral aspect and ventricular septum, which are vessel populations primarily derived from the endocardium. The proepicardium gave rise to a smaller fraction of vessels spaced relatively uniformly throughout the ventricular walls. Dorsal (SV-derived) and ventral (endocardial-derived) coronary vessels developed in response to different growth signals. The absence of VEGFC, which is expressed in the epicardium, dramatically inhibited dorsal and lateral coronary growth but left vessels on the ventral side unaffected. We propose that complementary SV-derived and endocardial-derived migratory routes unite to form the coronary vasculature and that the former requires VEGFC, revealing its role as a tissue-specific mediator of blood endothelial development.

    View details for DOI 10.1242/dev.113639

    View details for Web of Science ID 000345029600009

    View details for PubMedCentralID PMC4302936

  • Oxygen regulates human cytotrophoblast migration by controlling chemokine and receptor expression PLACENTA Schanz, A., Red-Horse, K., Hess, A. P., Baston-Buest, D. M., Heiss, C., Kruessel, J. S. 2014; 35 (12): 1089-1094


    Placental development involves the variation of oxygen supply due to vascular changes and cytotrophoblast invasion. Chemokines and their receptors play an important role during placental formation. Herein, the analysis of the chemokine/receptor pair CXCL12/CXCR4 and further chemokine receptors, such as CCR1, CCR7 and CXCR6 expression in human cytotrophoblasts was conducted.Human cytotrophoblasts were examined directly after isolation or after incubation with different oxygen tensions and a chemical HIF-stimulator for 12 h with realtime PCR, immunoblot, immunohistochemistry. Conditioned media of placental villi, decidua, and endothelial cells was used for ELISA analysis of CXL12. Cytotrophoblast migration assays were conducted applying conditioned media of endothelial cells, a CXCL12 gradient, and different oxygen level. Endometrial and decidual tissue was stained for CXCL12 expression.An upregulation of CXCL12, CXCR4, CCR1, CCR7 and CXCR6 was observed after cytotrophoblast differentiation. Low oxygen supply upregulated CXCR4, CCR7 and CXCR6, but downregulated CXCL12 and CCR1. In contrast to the HIF associated upregulation of the aforementioned proteins, downregulation of CXCL12 and CCR1 seemed to be HIF independent. Cytotrophoblast migration was stimulated by low oxygen, the application of a CXCL12 gradient and endothelial cell conditioned media. CXCL12 was detected in endometrial vessels, glands and conditioned media of placental and decidual tissue, but not decidual vessels.Taken together, oxygen supply and cytotrophoblast differentiation seem to be regulators of chemokine and receptor expression and function in human cytotrophoblasts. Therefore, this system seems to be involved in placental development, directed cytotrophoblast migration in the decidual compartment and a subsequent sufficient supply of the growing fetus.

    View details for DOI 10.1016/j.placenta.2014.09.012

    View details for Web of Science ID 000346953500019

    View details for PubMedID 25293376

  • VEGF-C and aortic cardiomyocytes guide coronary artery stem development JOURNAL OF CLINICAL INVESTIGATION Chen, H. I., Poduri, A., Numi, H., Kivela, R., Saharinen, P., McKay, A. S., Raftrey, B., Churko, J., Tian, X., Zhou, B., Wu, J. C., Alitalo, K., Red-Horse, K. 2014; 124 (11): 4899-4914


    Coronary arteries (CAs) stem from the aorta at 2 highly stereotyped locations, deviations from which can cause myocardial ischemia and death. CA stems form during embryogenesis when peritruncal blood vessels encircle the cardiac outflow tract and invade the aorta, but the underlying patterning mechanisms are poorly understood. Here, using murine models, we demonstrated that VEGF-C-deficient hearts have severely hypoplastic peritruncal vessels, resulting in delayed and abnormally positioned CA stems. We observed that VEGF-C is widely expressed in the outflow tract, while cardiomyocytes develop specifically within the aorta at stem sites where they surround maturing CAs in both mouse and human hearts. Mice heterozygous for islet 1 (Isl1) exhibited decreased aortic cardiomyocytes and abnormally low CA stems. In hearts with outflow tract rotation defects, misplaced stems were associated with shifted aortic cardiomyocytes, and myocardium induced ectopic connections with the pulmonary artery in culture. These data support a model in which CA stem development first requires VEGF-C to stimulate vessel growth around the outflow tract. Then, aortic cardiomyocytes facilitate interactions between peritruncal vessels and the aorta. Derangement of either step can lead to mispatterned CA stems. Studying this niche for cardiomyocyte development, and its relationship with CAs, has the potential to identify methods for stimulating vascular regrowth as a treatment for cardiovascular disease.

    View details for DOI 10.1172/JCI77483

    View details for Web of Science ID 000344203300026

  • Developmental Heterogeneity of Cardiac Fibroblasts Does Not Predict Pathological Proliferation and Activation CIRCULATION RESEARCH Ali, S. R., Ranjbarvaziri, S., Talkhabi, M., Zhao, P., Subat, A., Hojjat, A., Kamran, P., Mueller, A. M., Volz, K. S., Tang, Z., Red-Horse, K., Ardehali, R. 2014; 115 (7): 625-U81


    Fibrosis is mediated partly by extracellular matrix-depositing fibroblasts in the heart. Although these mesenchymal cells are reported to have multiple embryonic origins, the functional consequence of this heterogeneity is unknown.We sought to validate a panel of surface markers to prospectively identify cardiac fibroblasts. We elucidated the developmental origins of cardiac fibroblasts and characterized their corresponding phenotypes. We also determined proliferation rates of each developmental subset of fibroblasts after pressure overload injury.We showed that Thy1(+)CD45(-)CD31(-)CD11b(-)Ter119(-) cells constitute the majority of cardiac fibroblasts. We characterized these cells using flow cytometry, epifluorescence and confocal microscopy, and transcriptional profiling (using reverse transcription polymerase chain reaction and RNA-seq). We used lineage tracing, transplantation studies, and parabiosis to show that most adult cardiac fibroblasts derive from the epicardium, a minority arises from endothelial cells, and a small fraction from Pax3-expressing cells. We did not detect generation of cardiac fibroblasts by bone marrow or circulating cells. Interestingly, proliferation rates of fibroblast subsets on injury were identical, and the relative abundance of each lineage remained the same after injury. The anatomic distribution of fibroblast lineages also remained unchanged after pressure overload. Furthermore, RNA-seq analysis demonstrated that Tie2-derived and Tbx18-derived fibroblasts within each operation group exhibit similar gene expression profiles.The cellular expansion of cardiac fibroblasts after transaortic constriction surgery was not restricted to any single developmental subset. The parallel proliferation and activation of a heterogeneous population of fibroblasts on pressure overload could suggest that common signaling mechanisms stimulate their pathological response.

    View details for DOI 10.1161/CIRCRESAHA.115.303794

    View details for Web of Science ID 000342076700010

  • Developmental heterogeneity of cardiac fibroblasts does not predict pathological proliferation and activation. Circulation research Ali, S. R., Ranjbarvaziri, S., Talkhabi, M., Zhao, P., Subat, A., Hojjat, A., Kamran, P., Müller, A. M., Volz, K. S., Tang, Z., Red-Horse, K., Ardehali, R. 2014; 115 (7): 625-635


    Fibrosis is mediated partly by extracellular matrix-depositing fibroblasts in the heart. Although these mesenchymal cells are reported to have multiple embryonic origins, the functional consequence of this heterogeneity is unknown.We sought to validate a panel of surface markers to prospectively identify cardiac fibroblasts. We elucidated the developmental origins of cardiac fibroblasts and characterized their corresponding phenotypes. We also determined proliferation rates of each developmental subset of fibroblasts after pressure overload injury.We showed that Thy1(+)CD45(-)CD31(-)CD11b(-)Ter119(-) cells constitute the majority of cardiac fibroblasts. We characterized these cells using flow cytometry, epifluorescence and confocal microscopy, and transcriptional profiling (using reverse transcription polymerase chain reaction and RNA-seq). We used lineage tracing, transplantation studies, and parabiosis to show that most adult cardiac fibroblasts derive from the epicardium, a minority arises from endothelial cells, and a small fraction from Pax3-expressing cells. We did not detect generation of cardiac fibroblasts by bone marrow or circulating cells. Interestingly, proliferation rates of fibroblast subsets on injury were identical, and the relative abundance of each lineage remained the same after injury. The anatomic distribution of fibroblast lineages also remained unchanged after pressure overload. Furthermore, RNA-seq analysis demonstrated that Tie2-derived and Tbx18-derived fibroblasts within each operation group exhibit similar gene expression profiles.The cellular expansion of cardiac fibroblasts after transaortic constriction surgery was not restricted to any single developmental subset. The parallel proliferation and activation of a heterogeneous population of fibroblasts on pressure overload could suggest that common signaling mechanisms stimulate their pathological response.

    View details for DOI 10.1161/CIRCRESAHA.115.303794

    View details for PubMedID 25037571

  • Human induced pluripotent stem cell-derived cardiomyocytes as an in vitro model for coxsackievirus b3-induced myocarditis and antiviral drug screening platform. Circulation research Sharma, A., Marceau, C., Hamaguchi, R., Burridge, P. W., Rajarajan, K., Churko, J. M., Wu, H., Sallam, K. I., Matsa, E., Sturzu, A. C., Che, Y., Ebert, A., Diecke, S., Liang, P., Red-Horse, K., Carette, J. E., Wu, S. M., Wu, J. C. 2014; 115 (6): 556-566


    Viral myocarditis is a life-threatening illness that may lead to heart failure or cardiac arrhythmias. A major causative agent for viral myocarditis is the B3 strain of coxsackievirus, a positive-sense RNA enterovirus. However, human cardiac tissues are difficult to procure in sufficient enough quantities for studying the mechanisms of cardiac-specific viral infection.This study examined whether human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) could be used to model the pathogenic processes of coxsackievirus-induced viral myocarditis and to screen antiviral therapeutics for efficacy.hiPSC-CMs were infected with a luciferase-expressing coxsackievirus B3 strain (CVB3-Luc). Brightfield microscopy, immunofluorescence, and calcium imaging were used to characterize virally infected hiPSC-CMs for alterations in cellular morphology and calcium handling. Viral proliferation in hiPSC-CMs was quantified using bioluminescence imaging. Antiviral compounds including interferonβ1, ribavirin, pyrrolidine dithiocarbamate, and fluoxetine were tested for their capacity to abrogate CVB3-Luc proliferation in hiPSC-CMs in vitro. The ability of these compounds to reduce CVB3-Luc proliferation in hiPSC-CMs was consistent with reported drug effects in previous studies. Mechanistic analyses via gene expression profiling of hiPSC-CMs infected with CVB3-Luc revealed an activation of viral RNA and protein clearance pathways after interferonβ1 treatment.This study demonstrates that hiPSC-CMs express the coxsackievirus and adenovirus receptor, are susceptible to coxsackievirus infection, and can be used to predict antiviral drug efficacy. Our results suggest that the hiPSC-CM/CVB3-Luc assay is a sensitive platform that can screen novel antiviral therapeutics for their effectiveness in a high-throughput fashion.

    View details for DOI 10.1161/CIRCRESAHA.115.303810

    View details for PubMedID 25015077

    View details for PubMedCentralID PMC4149868

  • Exploring the world of human development and reproduction INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY Red-Horse, K., Drake, P. M., Fisher, S. 2014; 58 (2-4): 87-93


    Susan Fisher has spent her career studying human development, proteomics, and the intersection between the two. When she began studying human placentation, there had been extensive descriptive studies of this fascinating organ that intertwines with the mother's vasculature during pregnancy. Susan can be credited with numerous major findings on the mechanisms that regulate placental cytotrophoblast invasion. These include the discovery that cytotrophoblasts undergo vascular mimicry to insert themselves into uterine arteries, the finding that oxygen tension greatly effects placentation, and identifying how these responses go awry in pregnancy complications such as preeclamsia. Other important work has focused on the effect of post-translational modifications such as glycosylation on bacterial adhesion and reproduction. Susan has also forayed into the world of proteomics to identify cancer biomarkers. Because her work is truly groundbreaking, many of these findings inspire research in other laboratories around the world resulting in numerous follow up papers. Likewise, her mentoring and support inspires young scientists to go on and make their own important discoveries. In this interview, Susan shares what drove her science, how she continued to do important research while balancing other aspects of life, and provides insights for the next generation.

    View details for DOI 10.1387/ijdb.140063kr

    View details for Web of Science ID 000340702100004

    View details for PubMedID 25023674

  • Subepicardial endothelial cells invade the embryonic ventricle wall to form coronary arteries CELL RESEARCH Tian, X., Hu, T., Zhang, H., He, L., Huang, X., Liu, Q., Yu, W., He, L., Yang, Z., Zhang, Z., Zhong, T. P., Yang, X., Yang, Z., Yan, Y., Baldini, A., Sun, Y., Lu, J., Schwartz, R. J., Evans, S. M., Gittenberger-de Groot, A. C., Red-Horse, K., Zhou, B. 2013; 23 (9): 1075-1090


    Coronary arteries bring blood flow to the heart muscle. Understanding the developmental program of the coronary arteries provides insights into the treatment of coronary artery diseases. Multiple sources have been described as contributing to coronary arteries including the proepicardium, sinus venosus (SV), and endocardium. However, the developmental origins of coronary vessels are still under intense study. We have produced a new genetic tool for studying coronary development, an AplnCreER mouse line, which expresses an inducible Cre recombinase specifically in developing coronary vessels. Quantitative analysis of coronary development and timed induction of AplnCreER fate tracing showed that the progenies of subepicardial endothelial cells (ECs) both invade the compact myocardium to form coronary arteries and remain on the surface to produce veins. We found that these subepicardial ECs are the major sources of intramyocardial coronary vessels in the developing heart. In vitro explant assays indicate that the majority of these subepicardial ECs arise from endocardium of the SV and atrium, but not from ventricular endocardium. Clonal analysis of Apln-positive cells indicates that a single subepicardial EC contributes equally to both coronary arteries and veins. Collectively, these data suggested that subepicardial ECs are the major source of intramyocardial coronary arteries in the ventricle wall, and that coronary arteries and veins have a common origin in the developing heart.

    View details for DOI 10.1038/cr.2013.83

    View details for Web of Science ID 000323930200007

    View details for PubMedID 23797856

    View details for PubMedCentralID PMC3760626

  • Radial Construction of an Arterial Wall DEVELOPMENTAL CELL Greif, D. M., Kumar, M., Lighthouse, J. K., Hum, J., An, A., Ding, L., Red-Horse, K., Espinoza, F. H., Olson, L., Offermanns, S., Krasnow, M. A. 2012; 23 (3): 482-493


    Some of the most serious diseases involve altered size and structure of the arterial wall. Elucidating how arterial walls are built could aid understanding of these diseases, but little is known about how concentric layers of muscle cells and the outer adventitial layer are assembled and patterned around endothelial tubes. Using histochemical, clonal, and genetic analysis in mice, here we show that the pulmonary artery wall is constructed radially, from the inside out, by two separate but coordinated processes. One is sequential induction of successive cell layers from surrounding mesenchyme. The other is controlled invasion of outer layers by inner layer cells through developmentally regulated cell reorientation and radial migration. We propose that a radial signal gradient controls these processes and provide evidence that PDGF-B and at least one other signal contribute. Modulation of such radial signaling pathways may underlie vessel-specific differences and pathological changes in arterial wall size and structure.

    View details for DOI 10.1016/j.devcel.2012.07.009

    View details for Web of Science ID 000308776400007

    View details for PubMedID 22975322

    View details for PubMedCentralID PMC3500096

  • Coronary arteries form by developmental reprogramming of venous cells NATURE Red-Horse, K., Ueno, H., Weissman, I. L., Krasnow, M. A. 2010; 464 (7288): 549-U100


    Coronary artery disease is the leading cause of death worldwide. Determining the coronary artery developmental program could aid understanding of the disease and lead to new treatments, but many aspects of the process, including their developmental origin, remain obscure. Here we show, using histological and clonal analysis in mice and cardiac organ culture, that coronary vessels arise from angiogenic sprouts of the sinus venosus-the vein that returns blood to the embryonic heart. Sprouting venous endothelial cells dedifferentiate as they migrate over and invade the myocardium. Invading cells differentiate into arteries and capillaries; cells on the surface redifferentiate into veins. These results show that some differentiated venous cells retain developmental plasticity, and indicate that position-specific cardiac signals trigger their dedifferentiation and conversion into coronary arteries, capillaries and veins. Understanding this new reprogramming process and identifying the endogenous signals should suggest more natural ways of engineering coronary bypass grafts and revascularizing the heart.

    View details for DOI 10.1038/nature08873

    View details for Web of Science ID 000275974200039

    View details for PubMedID 20336138

    View details for PubMedCentralID PMC2924433

  • Lymphatic vessel dynamics in the uterine wall PLACENTA Red-Horse, K. 2008; 29: S55-S59


    During pregnancy, maternal uterine blood vessels undergo dramatic vascular remodeling. However, until now, little was known about whether the lymphatic circulation experiences similar changes and whether these vessels interact with placental cells that invade maternal tissue. Recent studies demonstrate that lymphatic vessels in the uterine wall are highly compartmentalized where their presence is mostly restricted to the deeper layers. In humans, this arrangement changes during pregnancy when extensive lymphangiogenesis occurs at the maternal-fetal interface. Placental cytotrophoblasts stimulate lymphatic growth in vivo and in vitro suggesting that they play a role in triggering pregnancy-induced decidual lymphangiogenesis. These data indicate that lymphatic vessels may have important functions at the implantation site during pregnancy.

    View details for DOI 10.1016/j.placenta.2007.11.011

    View details for Web of Science ID 000254629200012

    View details for PubMedID 18155143

    View details for PubMedCentralID PMC2435487