All Publications

  • Quantitative proteomics reveal lineage-specific protein profiles in iPSC-derived Marfan syndrome smooth muscle cells. Scientific reports Iosef, C., Pedroza, A. J., Cui, J. Z., Dalal, A. R., Arakawa, M., Tashima, Y., Koyano, T. K., Burdon, G., Churovich, S. M., Orrick, J. O., Pariani, M., Fischbein, M. P. 2020; 10 (1): 20392


    Marfan syndrome (MFS) is a connective tissue disorder caused by mutations in the FBN1 gene that produces wide disease phenotypic variability. The lack of ample genotype-phenotype correlation hinders translational study development aimed at improving disease prognosis. In response to this need, an induced pluripotent stem cell (iPSC) disease model has been used to test patient-specific cells by a proteomic approach. This model has the potential to risk stratify patients to make clinical decisions, including timing for surgical treatment. The regional propensity for aneurysm formation in MFS may be related to distinct smooth muscle cell (SMC) embryologic lineages. Thus, peripheral blood mononuclear cell (PBMC)-derived induced pluripotent stem cells (iPSC) were differentiated into lateral mesoderm (LM, aortic root) and neural crest (NC, ascending aorta/transverse arch) SMC lineages to model MFS aortic pathology. Isobaric Tags for Relative and Absolute Quantitation (iTRAQ) proteomic analysis by tandem mass spectrometry was applied to profile LM and NC iPSC SMCs from four MFS patients and two healthy controls. Analysis revealed 45 proteins with lineage-dependent expression in MFS patients, many of which were specific to diseased samples. Single protein-level data from both iPSC SMCs and primary MFS aortic root aneurysm tissue confirmed elevated integrin alphaV and reduced MRC2 in clinical disease specimens, validating the iPSC iTRAQ findings. Functionally, iPSC SMCs exhibited defective adhesion to a variety of extracellular matrix proteins, especially laminin-1 and fibronectin, suggesting altered cytoskeleton dynamics. This study defines the aortic embryologic origin-specific proteome in a validated iPSC SMC model to identify novel protein markers associated with MFS aneurysm phenotype. Translating iPSC findings into clinical aortic aneurysm tissue samples highlights the potential for iPSC-based methods to model MFS disease for mechanistic studies and therapeutic discovery in vitro.

    View details for DOI 10.1038/s41598-020-77274-w

    View details for PubMedID 33230159

  • Androgens Accentuate TGF-beta Dependent Erk/Smad Activation During Thoracic Aortic Aneurysm Formation in Marfan Syndrome Male Mice. Journal of the American Heart Association Tashima, Y., He, H., Cui, J. Z., Pedroza, A. J., Nakamura, K., Yokoyama, N., Iosef, C., Burdon, G., Koyano, T., Yamaguchi, A., Fischbein, M. P. 2020; 9 (20): e015773


    Background Male patients with Marfan syndrome have a higher risk of aortic events and root dilatation compared with females. The role androgens play during Marfan syndrome aneurysm development in males remains unknown. We hypothesized that androgens potentiate transforming growth factor beta induced Erk (extracellular-signal-regulated kinase)/Smad activation, contributing to aneurysm progression in males. Methods and Results Aortic diameters in Fbn1C1039G/+ and littermate wild-type controls were measured at ages 6, 8, 12, and 16weeks. Fbn1C1039G/+ males were treated with (1) flutamide (androgen receptor blocker) or (2) vehicle control from age 6 to 16weeks and then euthanized. p-Erk1/2, p-Smad2, and matrix metalloproteinase (MMP) activity were measured in ascending/aortic root and descending aorta specimens. Fbn1C1039G/+ male and female ascending/aortic root-derived smooth muscle cells were utilized in vitro to measure Erk/Smad activation and MMP-2 activity following dihydrotestosterone, flutamide or transforming growth factor beta 1 treatment. Fbn1C1039G/+ males have increased aneurysm growth. p-Erk1/2 and p-Smad2 were elevated in ascending/aortic root specimens at age 16weeks. Corresponding with enhanced Erk/Smad signaling, MMP-2 activity was higher in Fbn1C1039G/+ males. In vitro smooth muscle cell studies revealed that dihydrotestosterone potentiates transforming growth factor beta-induced Erk/Smad activation and MMP-2 activity, which is reversed by flutamide treatment. Finally, in vivo flutamide treatment reduced aneurysm growth via p-Erk1/2 and p-Smad2 reduction in Fbn1C1039G/+ males. Conclusions Fbn1C1039G/+ males have enhanced aneurysm growth compared with females associated with enhanced p-Erk1/2 and p-Smad2 activation. Mechanistically, in vitro smooth muscle cell studies suggested that dihydrotestosterone potentiates transforming growth factor beta induced Erk/Smad activation. As biological proof of concept, flutamide treatment attenuated aneurysm growth and p-Erk1/2 and p-Smad2 signaling in Fbn1C1039G/+ males.

    View details for DOI 10.1161/JAHA.119.015773

    View details for PubMedID 33059492

  • Endovascular Aortic Repair After Proximal Stent Graft Migration of a Modified Frozen Elephant Trunk. Innovations (Philadelphia, Pa.) Dalal, A. R., Pedroza, A. J., Iwakoshi, S. n., Lee, J. T., Fleischmann, D. n., Watkins, A. C. ; 15 (2): 169–72


    We describe the endovascular repair for a proximal endograft migration following a modified frozen elephant trunk (mFET) repair for a retrograde type A dissection (retro-A AD). A 40-year-old man presented with a type B aortic dissection that progressed to a retro-A AD. He was emergently taken to the operating room for an mFET repair. Computed tomography (CT) angiogram on the day of discharge revealed that the proximal end of the endograft migrated through the primary intimal tear resulting in obstruction of true lumen flow. The patient returned to the catheterization lab for endovascular repair utilizing a through-and-through wire to extend the endograft proximally and a left carotid-subclavian artery bypass. This complication highlights the importance of postoperative CT surveillance and the endovascular technique utilized to restore aortic true lumen flow.

    View details for DOI 10.1177/1556984520902839

    View details for PubMedID 32352908

  • Single-Cell Transcriptomic Profiling of Vascular Smooth Muscle Cell Phenotype Modulation in Marfan Syndrome Aortic Aneurysm. Arteriosclerosis, thrombosis, and vascular biology Pedroza, A. J., Tashima, Y., Shad, R., Cheng, P., Wirka, R., Churovich, S., Nakamura, K., Yokoyama, N., Cui, J. Z., Iosef, C., Hiesinger, W., Quertermous, T., Fischbein, M. P. 2020: ATVBAHA120314670


    OBJECTIVE: To delineate temporal and spatial dynamics of vascular smooth muscle cell (SMC) transcriptomic changes during aortic aneurysm development in Marfan syndrome (MFS). Approach and Results: We performed single-cell RNA sequencing to study aortic root/ascending aneurysm tissue from Fbn1C1041G/+ (MFS) mice and healthy controls, identifying all aortic cell types. A distinct cluster of transcriptomically modulated SMCs (modSMCs) was identified in adult Fbn1C1041G/+ mouse aortic aneurysm tissue only. Comparison with atherosclerotic aortic data (ApoE-/- mice) revealed similar patterns of SMC modulation but identified an MFS-specific gene signature, including plasminogen activator inhibitor-1 (Serpine1) and Kruppel-like factor 4 (Klf4). We identified 481 differentially expressed genes between modSMC and SMC subsets; functional annotation highlighted extracellular matrix modulation, collagen synthesis, adhesion, and proliferation. Pseudotime trajectory analysis of Fbn1C1041G/+ SMC/modSMC transcriptomes identified genes activated differentially throughout the course of phenotype modulation. While modSMCs were not present in young Fbn1C1041G/+ mouse aortas despite small aortic aneurysm, multiple early modSMCs marker genes were enriched, suggesting activation of phenotype modulation. modSMCs were not found in nondilated adult Fbn1C1041G/+ descending thoracic aortas. Single-cell RNA sequencing from human MFS aortic root aneurysm tissue confirmed analogous SMC modulation in clinical disease. Enhanced expression of TGF (transforming growth factor)-beta-responsive genes correlated with SMC modulation in mouse and human data sets.CONCLUSIONS: Dynamic SMC phenotype modulation promotes extracellular matrix substrate modulation and aortic aneurysm progression in MFS. We characterize the disease-specific signature of modSMCs and provide temporal, transcriptomic context to the current understanding of the role TGF-beta plays in MFS aortopathy. Collectively, single-cell RNA sequencing implicates TGF-beta signaling and Klf4 overexpression as potential upstream drivers of SMC modulation.

    View details for DOI 10.1161/ATVBAHA.120.314670

    View details for PubMedID 32698686

  • Divergent effects of canonical and non-canonical TGF-beta signalling on mixed contractile-synthetic smooth muscle cell phenotype in human Marfan syndrome aortic root aneurysms. Journal of cellular and molecular medicine Pedroza, A. J., Koyano, T., Trojan, J., Rubin, A., Palmon, I., Jaatinen, K., Burdon, G., Chang, P., Tashima, Y., Cui, J. Z., Berry, G., Iosef, C., Fischbein, M. P. 2019


    Aortic root aneurysm formation is a cardinal feature of Marfan syndrome (MFS) and likely TGF-beta driven via Smad (canonical) and ERK (non-canonical) signalling. The current study assesses human MFS vascular smooth muscle cell (SMC) phenotype, focusing on individual contributions by Smad and ERK, with Notch3 signalling identified as a novel compensatory mechanism against TGF-beta-driven pathology. Although significant ERK activation and mixed contractile gene expression patterns were observed by traditional analysis, this did not directly correlate with the anatomic site of the aneurysm. Smooth muscle cell phenotypic changes were TGF-beta-dependent and opposed by ERK in vitro, implicating the canonical Smad pathway. Bulk SMC RNA sequencing after ERK inhibition showed that ERK modulates cell proliferation, apoptosis, inflammation, and Notch signalling via Notch3 in MFS. Reversing Notch3 overexpression with siRNA demonstrated that Notch3 promotes several protective remodelling pathways, including increased SMC proliferation, decreased apoptosis and reduced matrix metalloproteinase activity, in vitro. In conclusion, in human MFS aortic SMCs: (a) ERK activation is enhanced but not specific to the site of aneurysm formation; (b) ERK opposes TGF-beta-dependent negative effects on SMC phenotype; (c) multiple distinct SMC subtypes contribute to a 'mixed' contractile-synthetic phenotype in MFS aortic aneurysm;and (d) ERK drives Notch3 overexpression, a potential pathway for tissue remodelling in response to aneurysm formation.

    View details for DOI 10.1111/jcmm.14921

    View details for PubMedID 31886938

  • Acute type A dissection causing impending rupture of abdominal aortic aneurysm previously treated with EVAR. Annals of vascular surgery Ogawa, Y., Watkins, A. C., Lee, A., Iwakoshi, S., Dua, A., Pedroza, A. J., Dake, M. D., Lee, J. T. 2019


    This report describes the rapid expansion of a previously excluded abdominal aortic aneurysm (AAA) following type A aortic dissection repair in a 74-year-old male. Following successful hemi-arch replacement, CT angiography (CTA) showed residual dissection throughout the thoracoabdominal aorta which had created a proximal endoleak at the prior endovascular stentgraft resulting in rapid growth of the residual AAA sac. Urgent thoracic endovascular aortic repair (TEVAR) did not fully obliterate false lumen flow allowing further unstable expansion of the AAA and abdominal pain. This was ultimately managed with an open replacement of the infrarenal neck with a Dacron interposition graft sewn to the prior EVAR. Post-op CTA showed resolution of the false lumen communication to the infrarenal AAA and no further endoleak. Open interposition AAA neck replacement is a possible treatment for new onset endoleak in patients with aortic dissection following prior infrarenal EVAR.

    View details for DOI 10.1016/j.avsg.2019.11.047

    View details for PubMedID 31863952

  • Anatomically specific reactive oxygen species production participates in Marfan syndrome aneurysm formation. Journal of cellular and molecular medicine Emrich, F., Penov, K., Arakawa, M., Dhablania, N., Burdon, G., Pedroza, A. J., Koyano, T. K., Kim, Y. M., Raaz, U., Connolly, A. J., Iosef, C., Fischbein, M. P. 2019


    Marfan syndrome (MFS) is a connective tissue disorder that results in aortic root aneurysm formation. Reactive oxygen species (ROS) seem to play a role in aortic wall remodelling in MFS, although the mechanism remains unknown. MFS Fbn1C1039G/+ mouse root/ascending (AS) and descending (DES) aortic samples were examined using DHE staining, lucigenin-enhanced chemiluminescence (LGCL), Verhoeff's elastin-Van Gieson staining (elastin breakdown) and in situ zymography for protease activity. Fbn1C1039G/+ AS- or DES-derived smooth muscle cells (SMC) were treated with anti-TGF-beta antibody, angiotensin II (AngII), anti-TGF-beta antibody+AngII, or isotype control. ROS were detected during early aneurysm formation in the Fbn1C1039G/+ AS aorta, but absent in normal-sized DES aorta. Fbn1C1039G/+ mice treated with the unspecific NADPH oxidase inhibitor, apocynin reduced AS aneurysm formation, with attenuated elastin fragmentation. In situ zymography revealed apocynin treatment decreased protease activity. In vitro SMC studies showed Fbn1C1039G/+ -derived AS SMC had increased NADPH activity compared to DES-derived SMC. AS SMC NADPH activity increased with AngII treatment and appeared TGF-beta dependent. In conclusion, ROS play a role in MFS aneurysm development and correspond anatomically with aneurysmal aortic segments. ROS inhibition via apocynin treatment attenuates MFS aneurysm progression. AngII enhances ROS production in MFS AS SMCs and is likely TGF-beta dependent.

    View details for DOI 10.1111/jcmm.14587

    View details for PubMedID 31402541

  • Statins Reduce Thoracic Aortic Aneurysm Growth in Marfan Syndrome Mice via Inhibition of the Ras-Induced ERK (Extracellular Signal-Regulated Kinase) Signaling Pathway JOURNAL OF THE AMERICAN HEART ASSOCIATION Sato, T., Arakawa, M., Tashima, Y., Tsuboi, E., Burdon, G., Trojan, J., Koyano, T., Young-Nam Youn, Penov, K., Pedroza, A. J., Shabazzi, M., Palmon, I., Nguyen, M., Connolly, A. J., Yamaguchi, A., Fischbein, M. P. 2018; 7 (21): e008543


    Background Statins reduce aneurysm growth in mouse models of Marfan syndrome, although the mechanism is unknown. In addition to reducing cholesterol, statins block farnesylation and geranylgeranylation, which participate in membrane-bound G-protein signaling, including Ras. We dissected the prenylation pathway to define the effect of statins on aneurysm reduction. Methods and Results Fbn1C1039G/+ mice were treated with (1) pravastatin (HMG-CoA [3-hydroxy-3-methylglutaryl coenzyme A] reductase inhibitor), (2) manumycin A ( MA ; FPT inhibitor), (3) perillyl alcohol ( GGPT 1 and -2 inhibitor), or (4) vehicle control from age 4 to 8 weeks and euthanized at 12 weeks. Histological characterization was performed. Protein analysis was completed on aortic specimens to measure ERK (extracellular signal-regulated kinase) signaling. In vitro Fbn1C1039G/+ aortic smooth muscle cells were utilized to measure Ras-dependent ERK signaling and MMP (matrix metalloproteinase) activity. Pravastatin and MA significantly reduced aneurysm growth compared with vehicle control (n=8 per group). In contrast, PA did not significantly decrease aneurysm size. Histology illustrated reduced elastin breakdown in MA -treated mice compared with vehicle control (n=5 per group). Although elevated in control Marfan mice, both phosphorylated c-Raf and phosphorylated ERK 1/2 were significantly reduced in MA -treated mice (4-5 per group). In vitro smooth muscle cell studies confirmed phosphorylated cR af and phosphorylated ERK 1/2 signaling was elevated in Fbn1C1039G/+ smooth muscle cells (n=5 per group). Fbn1C1039G/+ smooth muscle cell Ras-dependent ERK signaling and MMP activity were reduced following MA treatment (n=5 per group). Corroborating in vitro findings, MMP activity was also decreased in pravastatin-treated mice. Conclusions Aneurysm reduction in Fbn1C1039G/+ mice following pravastatin and MA treatment was associated with a decrease in Ras-dependent ERK signaling. MMP activity can be reduced by diminishing Ras signaling.

    View details for PubMedID 30571378

  • Emergency valve-sparing aortic root replacement and coronary artery bypass grafting for giant left sinus of Valsalva aneurysm presenting as acute coronary syndrome JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY Pedroza, A. J., Brewer, Z. E., Lee, A. M. 2018; 156 (2): E81–E84
  • Emergency valve-sparing aortic root replacement and coronary artery bypass grafting for giant left sinus of Valsalva aneurysm presenting as acute coronary syndrome. The Journal of thoracic and cardiovascular surgery Pedroza, A. J., Brewer, Z. E., Lee, A. M. 2018

    View details for PubMedID 29615334

  • Long-term miR-29b suppression reduces aneurysm formation in a Marfan mouse model. Physiological reports Okamura, H., Emrich, F., Trojan, J., Chiu, P., Dalal, A. R., Arakawa, M., Sato, T., Penov, K., Koyano, T., Pedroza, A., Connolly, A. J., Rabinovitch, M., Alvira, C., Fischbein, M. P. 2017; 5 (8)


    Aortic root aneurysm formation and subsequent dissection and/or rupture remain the leading cause of death in patients with Marfan syndrome. Our laboratory has reported that miR-29b participates in aortic root/ascending aorta extracellular matrix remodeling during early aneurysm formation in Fbn1(C1039G/+) Marfan mice. Herein, we sought to determine whether miR-29b suppression can reduce aneurysm formation long-term. Fbn1(C1039G/+) Marfan mice were treated with retro-orbital LNA-anti-miR-29b inhibitor or scrambled-control-miR before aneurysms develop either (1) a single dose prenatally (pregnant Fbn1(C1039G/+) mice at 14.5 days post-coitum) (n = 8-10, each group) or (2) postnatally every other week, from 2 to 22 weeks of age, and sacrificed at 24 weeks (n = 8-10, each group). To determine if miR-29b blockade was beneficial even after aneurysms develop, a third group of animals were treated every other week, starting at 8 weeks of age, until sacrificed (n = 4-6, each group). miR-29b inhibition resulted in aneurysm reduction, increased elastogenesis, decreased matrix metalloproteinase activity and decreased elastin breakdown. Prenatal LNA-anti-miR-29b inhibitor treatment decreased aneurysm formation up to age 32 weeks, whereas postnatal treatment was effective up to 16 weeks. miR-29b blockade did not slow aortic growth once aneurysms already developed. Systemic miR-29b inhibition significantly reduces aneurysm development long-term in a Marfan mouse model. Drug administration during aortic wall embryologic development appears fundamental. miR-29b suppression could be a potential therapeutic target for reducing aneurysm formation in Marfan syndrome patients.

    View details for DOI 10.14814/phy2.13257

    View details for PubMedID 28455451

  • Long-term miR-29b suppression reduces aneurysm formation in a Marfan mouse model PHYSIOLOGICAL REPORTS Okamura, H., Emrich, F., Trojan, J., Chiu, P., Dalal, A. R., Arakawa, M., Sato, T., Penov, K., Koyano, T., Pedroza, A., Connolly, A. J., Rabinovitch, M., Alvira, C., Fischbein, M. P. 2017; 5 (8)
  • Enhanced Caspase Activity Contributes to Aortic Wall Remodeling and Early Aneurysm Development in a Murine Model of Marfan Syndrome ARTERIOSCLEROSIS THROMBOSIS AND VASCULAR BIOLOGY Emrich, F. C., Okamura, H., Dalal, A. R., Penov, K., Merk, D. R., Raaz, U., Hennigs, J. K., Chin, J. T., Miller, M. O., Pedroza, A. J., Craig, J. K., Koyano, T. K., Blankenberg, F. G., Connolly, A. J., Mohr, F. W., Alvira, C. M., Rabinovitch, M., Fischbein, M. P. 2015; 35 (1): 146-154


    Rupture and dissection of aortic root aneurysms remain the leading causes of death in patients with the Marfan syndrome, a hereditary connective tissue disorder that affects 1 in 5000 individuals worldwide. In the present study, we use a Marfan mouse model (Fbn1(C1039G/+)) to investigate the biological importance of apoptosis during aneurysm development in Marfan syndrome.Using in vivo single-photon emission computed tomographic-imaging and ex vivo autoradiography for Tc99m-annexin, we discovered increased apoptosis in the Fbn1(C1039G/+) ascending aorta during early aneurysm development peaking at 4 weeks. Immunofluorescence colocalization studies identified smooth muscle cells (SMCs) as the apoptotic cell population. As biological proof of concept that early aortic wall apoptosis plays a role in aneurysm development in Marfan syndrome, Fbn1(C1039G/+) mice were treated daily from 2 to 6 weeks with either (1) a pan-caspase inhibitor, Q-VD-OPh (20 mg/kg), or (2) vehicle control intraperitoneally. Q-VD-OPh treatment led to a significant reduction in aneurysm size and decreased extracellular matrix degradation in the aortic wall compared with control mice. In vitro studies using Fbn1(C1039G/+) ascending SMCs showed that apoptotic SMCs have increased elastolytic potential compared with viable cells, mostly because of caspase activity. Moreover, in vitro (1) cell membrane isolation, (2) immunofluorescence staining, and (3) scanning electron microscopy studies illustrate that caspases are expressed on the exterior cell surface of apoptotic SMCs.Caspase inhibition attenuates aneurysm development in an Fbn1(C1039G/+) Marfan mouse model. Mechanistically, during apoptosis, caspases are expressed on the cell surface of SMCs and likely contribute to elastin degradation and aneurysm development in Marfan syndrome.

    View details for DOI 10.1161/ATVBAHA.114.304364

    View details for PubMedID 25359856