News Article | April 17, 2017
A team of biomedical engineering researchers, led by the University of Minnesota, has created a revolutionary 3D-bioprinted patch that can help heal scarred heart tissue after a heart attack. The discovery is a major step forward in treating patients with tissue damage after a heart attack. The research study is published today in Circulation Research, a journal published by the American Heart Association. Researchers have filed a patent on the discovery. According to the American Heart Association, heart disease is the No. 1 cause of death in the U.S. killing more than 360,000 people a year. During a heart attack, a person loses blood flow to the heart muscle and that causes cells to die. Our bodies can't replace those heart muscle cells so the body forms scar tissue in that area of the heart, which puts the person at risk for compromised heart function and future heart failure. In this study, researchers from the University of Minnesota-Twin Cities, University of Wisconsin-Madison, and University of Alabama-Birmingham used laser-based 3D-bioprinting techniques to incorporate stem cells derived from adult human heart cells on a matrix that began to grow and beat synchronously in a dish in the lab. When the cell patch was placed on a mouse following a simulated heart attack, the researchers saw significant increase in functional capacity after just four weeks. Since the patch was made from cells and structural proteins native to the heart, it became part of the heart and absorbed into the body, requiring no further surgeries. "This is a significant step forward in treating the No. 1 cause of death in the U.S.," said Brenda Ogle, an associate professor of biomedical engineering at the University of Minnesota. "We feel that we could scale this up to repair hearts of larger animals and possibly even humans within the next several years." Ogle said that this research is different from previous research in that the patch is modeled after a digital, three-dimensional scan of the structural proteins of native heart tissue. The digital model is made into a physical structure by 3D printing with proteins native to the heart and further integrating cardiac cell types derived from stem cells. Only with 3D printing of this type can we achieve one micron resolution needed to mimic structures of native heart tissue. "We were quite surprised by how well it worked given the complexity of the heart," Ogle said. "We were encouraged to see that the cells had aligned in the scaffold and showed a continuous wave of electrical signal that moved across the patch." Ogle said they are already beginning the next step to develop a larger patch that they would test on a pig heart, which is similar in size to a human heart. The research was funded by the National Science Foundation, National Institutes of Health, University of Minnesota Lillehei Heart Institute, and University of Minnesota Institute for Engineering in Medicine. In addition to Ogle, other biomedical engineering researchers who were part of the team include Molly E. Kupfer, Jangwook P. Jung, Libang Yang, Patrick Zhang, and Brian T. Freeman from the University of Minnesota; Paul J. Campagnola, Yong Da Sie, Quyen Tran, and Visar Ajeti from the University of Wisconsin-Madison; and Jianyi Zhang, Ling Gao, and Vladimir G. Fast from the University of Alabama, To read the full research paper entitled "Myocardial Tissue Engineering With Cells Derived from Human Induced-Pluripotent Stem Cells and a Native-Like, High-Resolution, 3-Dimensionally Printed Scaffold," visit the Circulation Research website.
Adhikari N.,Lillehei Heart Institute |
Basi D.L.,Developmental Surgical Science |
Carlson M.,Lillehei Heart Institute |
Mariash A.,Lillehei Heart Institute |
And 7 more authors.
Arteriosclerosis, Thrombosis, and Vascular Biology | Year: 2011
Objective- The goal of this study was to test the contributing role of increasing glucose uptake in vascular smooth muscle cells (VSMCs) in vascular complications and disease. Methods and results- A murine genetic model was established in which glucose trasporter 1 (GLUT1), the non-insulin-dependent glucose transporter protein, was overexpressed in smooth muscle using the sm22α promoter. Overexpression of GLUT1 in smooth muscle led to significant increases in glucose uptake (n=3, P<0.0001) as measured using radiolabeled 2-deoxyglucose. Fasting blood glucose, insulin, and nonesterified fatty acids were unchanged. Contractility in aortic ring segments was decreased in sm22α-GLUT1 mice (n=10, P<0.04). In response to vascular injury, sm22α-GLUT1 mice exhibited a proinflammatory phenotype, including a significant increase in the percentage of neutrophils in the lesion (n=4, P<0.04) and an increase in monocyte chemoattractant protein-1 (MCP-1) immunofluorescence. Circulating haptoglobin and glutathione/total glutathione were significantly higher in the sm22α-GLUT1 mice postinjury compared with controls (n=4, P<0.05), suggesting increased flux through the pentose phosphate pathway. sm22α-GLUT1 mice exhibited significant medial hypertrophy following injury that was associated with a significant increase in the percentage of VSMCs in the media staining positive for nuclear phosphoSMAD2/3 (n=4, P<0.003). Conclusion- In summary, these findings suggest that increased glucose uptake in VSMCs impairs vascular contractility and accelerates a proinflammatory, neutrophil-rich lesion in response to injury, as well as medial hypertrophy, which is associated with enhanced transforming growth factor-β activity. © 2011 American Heart Association. All rights reserved.
Caprioli A.,Center for Developmental Biology |
Koyano-Nakagawa N.,University of Minnesota |
Koyano-Nakagawa N.,Lillehei Heart Institute |
Iacovino M.,University of Minnesota |
And 6 more authors.
Circulation | Year: 2011
Background-: Recent studies suggest that the hematopoietic and cardiac lineages have close ontogenic origins, and that an early mesodermal cell population has the potential to differentiate into both lineages. Studies also suggest that specification of these lineages is inversely regulated. However, the transcriptional networks that govern the cell fate specification of these progenitors are incompletely defined. Methods and results-: Here, we show that Nkx2-5 regulates the hematopoietic/erythroid fate of the mesoderm precursors early during cardiac morphogenesis. Using transgenic technologies to isolate Nkx2-5 expressing cells, we observed an induction of the erythroid molecular program, including Gata1, in the Nkx2-5-null embryos. We further observed that overexpression of Nkx2-5 with an Nkx2-5-inducible embryonic stem cell system significantly repressed Gata1 gene expression and suppressed the hematopoietic/erythroid potential, but not the endothelial potential, of the embryonic stem cells. This suppression was cell-autonomous, and was partially rescued by overexpressing Gata1. In addition, we demonstrated that Nkx2-5 binds to the Gata1 gene enhancer and represses the transcriptional activity of the Gata1 gene. Conclusions-: Our results demonstrate that the hematopoietic/ erythroid cell fate is suppressed via Nkx2-5 during mesodermal fate determination, and that the Gata1 gene is one of the targets that are suppressed by Nkx2-5. © 2011 American Heart Association, Inc.
Cotsapas C.,Cambridge Broad Institute |
Cotsapas C.,Harvard University |
Cotsapas C.,Massachusetts General Hospital |
Prokunina-Olsson L.,U.S. National Cancer Institute |
And 12 more authors.
Diabetologia | Year: 2010
Aims/hypothesis: Genetic mapping has identified over 20 loci contributing to genetic risk of type 2 diabetes. The next step is to identify the genes and mechanisms regulating the contributions of genetic risk to disease. The goal of this study was to evaluate the effect of age, height, weight and risk alleles on expression of candidate genes in diabetes-associated regions in three relevant human tissues. Methods: We measured transcript abundance for WFS1, KCNJ11, TCF2 (also known as HNF1B), PPARG, HHEX, IDE, CDKAL1, CDKN2A, CDKN2B, IGF2BP2, SLC30A8 and TCF7L2 by quantitative RT-PCR in human pancreas (n=50), colon (n=195) and liver (n=50). Tissue samples were genotyped for single nucleotide polymorphisms (SNPs) associated with type 2 diabetes. The effects of age, height, weight, tissue and SNP on RNA expression were tested by linear modelling. Results: Expression of all genes exhibited tissue bias. Immunohistochemistry confirmed the findings for HHEX, IDE and SLC30A8, which showed strongest tissue-specific mRNA expression bias. Neither age, height nor weight were associated with gene expression. We found no evidence that type 2 diabetes-associated SNPs affect neighbouring gene expression (cis-expression quantitative trait loci) in colon, pancreas and liver. Conclusions/ interpretation: This study provides new evidence that tissue-type, but not age, height, weight or SNPs in or near candidate genes associated with increased risk of type 2 diabetes are strong contributors to differential gene expression in the genes and tissues examined. © 2010 Springer-Verlag.
Lu Z.,Minneapolis |
Lu Z.,Center for Vascular Biology |
Xu X.,Minneapolis |
Xu X.,Center for Vascular Biology |
And 19 more authors.
Circulation | Year: 2010
Phosphodiesterase type 5 (PDE5) inhibition has been shown to exert profound beneficial effects in the failing heart, suggesting a significant role for PDE5 in the development of congestive heart failure (CHF). The purpose of this study is to test the hypothesis that oxidative stress causes increased PDE5 expression in cardiac myocytes and that increased PDE5 contributes to the development of CHF. METHODS AND RESULTS: Myocardial PDE5 expression and cellular distribution were determined in left ventricular samples from patients with end-stage CHF and normal donors and from mice after transverse aortic constriction (TAC)-induced CHF. Compared with donor human hearts, myocardial PDE5 protein was increased ≥4.5-fold in CHF samples, and the increase of myocardial PDE5 expression was significantly correlated with myocardial oxidative stress markers 3′-nitrotyrosine or 4-hydroxynonenal expression (P<0.05). Histological examination demonstrated that PDE5 was mainly expressed in vascular smooth muscle in normal donor hearts, but its expression was increased in both cardiac myocytes and vascular smooth muscle of CHF hearts. Myocardial PDE5 protein content and activity also increased in mice after TAC-induced CHF (P<0.05). When the superoxide dismutase (SOD) mimetic M40401 was administered to attenuate oxidative stress, the increased PDE5 protein and activity caused by TAC was blunted, and the hearts were protected against left ventricular hypertrophy and CHF. Conversely, increased myocardial oxidative stress in superoxide dismutase 3 knockout mice caused a greater increase of PDE5 expression and CHF after TAC. In addition, administration of sildenafil to inhibit PDE5 attenuated TAC-induced myocardial oxidative stress, PDE5 expression, and CHF. CONCLUSIONS: Myocardial oxidative stress increases PDE5 expression in the failing heart. Reducing oxidative stress by treatment with M40401 attenuated cardiomyocyte PDE5 expression. This and selective inhibition of PDE5 protected the heart against pressure overload-induced left ventricular hypertrophy and CHF. © 2010 American Heart Association, Inc.
Bosnakovski D.,Lillehei Heart Institute |
Bosnakovski D.,University of Minnesota |
Bosnakovski D.,Goce Delcev University of Štip |
Choi S.H.,Lillehei Heart Institute |
And 7 more authors.
Skeletal Muscle | Year: 2014
Background: Facioscapulohumeral muscular dystrophy (FSHD) is caused by epigenetic alterations at the D4Z4 macrosatellite repeat locus on chromosome 4, resulting in inappropriate expression of the DUX4 protein. The DUX4 protein is therefore the primary molecular target for therapeutic intervention.Methods: We have developed a high-throughput screen based on the toxicity of DUX4 when overexpressed in C2C12 myoblasts, and identified inhibitors of DUX4-induced toxicity from within a diverse set of 44,000 small, drug-like molecules. A total of 1,280 hits were then subjected to secondary screening for activity against DUX4 expressed by 3T3 fibroblasts, for absence of activity against the tet-on system used to conditionally express DUX4, and for potential effects on cellular proliferation rate.Results: This allowed us to define a panel of 52 compounds to use as probes to identify essential pathways of DUX4 activity. We tested these compounds for their ability to protect wild-type cells from other types of cell death-inducing insults. Remarkably, we found that 60% of the DUX4 toxicity inhibitors that we identified also protected cells from tert-butyl hydrogen peroxide, an oxidative stress-inducing compound. Compounds did not protect against death induced by caspase activation, DNA damage, protein misfolding, or ER stress. Encouragingly, many of these compounds are also protective against DUX4 expression in human cells.Conclusion: These data suggest that oxidative stress is a dominant pathway through which DUX4-provoked toxicity is mediated in this system, and we speculate that enhancing the oxidative stress response pathway might be clinically beneficial in FSHD. © 2014 Bosnakovski et al.; licensee BioMed Central Ltd.
Urick A.K.,University of Minnesota |
Hawk L.M.L.,University of Minnesota |
Cassel M.K.,University of Minnesota |
Mishra N.K.,University of Minnesota |
And 6 more authors.
ACS Chemical Biology | Year: 2015
Bromodomain-containing protein dysregulation is linked to cancer, diabetes, and inflammation. Selective inhibition of bromodomain function is a newly proposed therapeutic strategy. We describe a 19F NMR dual screening method for small molecule discovery using fluorinated tryptophan resonances on two bromodomain-containing proteins. The chemical shift dispersion of 19F resonances within fluorine-labeled proteins enables the simultaneous analysis of two fluorinated bromodomains by NMR. A library of 229 small molecules was screened against the first bromodomain of Brd4 and the BPTF bromodomain. We report the first small molecule selective for BPTF over Brd4, termed AU1. The Kd = 2.8 for AU1, which is active in a cell-based reporter assay. No binding is detected with Brd4. Three new Brd4 inhibitors with submicromolar affinity were also discovered. Brd4 hits were validated in a thermal stability assay and potency determined via fluorescence anisotropy. The speed, ease of interpretation, and low protein concentration needed for protein-observed 19F NMR experiments in a multiprotein format offers a new method to discover and characterize selective ligands for bromodomain-containing proteins. © 2015 American Chemical Society.
Hu X.,Lillehei Heart Institute |
Hu X.,University of Minnesota |
Atzler D.,University of Hamburg |
Xu X.,Lillehei Heart Institute |
And 15 more authors.
Arteriosclerosis, Thrombosis, and Vascular Biology | Year: 2011
Objective-: The objective of this study was to identify the role of dimethylarginine dimethylaminohydrolase-1 (DDAH1) in degrading the endogenous nitric oxide synthase inhibitors asymmetrical dimethylarginine (ADMA) and N g-monomethyl-L-arginine (L-NMMA). Methods and Results-: We generated a global-DDAH1 gene-deficient (DDAH1-/-) mouse strain to examine the role of DDAH1 in ADMA and L-NMMA degradation and the physiological consequences of loss of DDAH1. Plasma and tissue ADMA and L-NMMA levels in DDAH1 -/- mice were several folds higher than in wild-type mice, but growth and development of these DDAH1-/- mice were similar to those of their wild-type littermates. Although the expression of DDAH2 was unaffected, DDAH activity was undetectable in all tissues tested. These findings indicate that DDAH1 is the critical enzyme for ADMA and L-NMMA degradation. Blood pressure was ≈20 mm Hg higher in the DDAH1-/- mice than in wild-type mice, but no other cardiovascular phenotype was found under unstressed conditions. Crossing DDAH1+/- male with DDAH1+/- female mice yielded DDAH1+/+, DDAH1+/-, and DDAH1-/- mice at the anticipated ratio of 1:2:1, indicating that DDAH1 is not required for embryonic development in this strain. Conclusion-: Our findings indicate that DDAH1 is required for metabolizing ADMA and L-NMMA in vivo, whereas DDAH2 had no detectable role for degrading ADMA and L-NMMA. © 2011 American Heart Association, Inc.