Engineering Microphysiological Systems for Human Cardiac Disease Modeling

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1 Engineering Microphysiological Systems for Human Cardiac Disease Modeling Megan L. McCain, PhD Chonette Early Career Chair Assistant Professor of Biomedical Engineering and Stem Cell Biology and Regenerative Medicine University of Southern California Laboratory for Living Systems Engineering

2 The Laboratory for Living Systems Engineering Undergraduate Students: Gio Suh, Archana Bettadapur, Clara Hua, Julie Strickland, Kevin Kim, Alyssa Viscio, Holly Huber, Caitlin Reck, Shadi Razipour, Luann Raposo, Sarah Kim, Celeste Goodwin Harvard University: Prof. Kit Parker and the Disease Biophysics Group, School of Engineering and Applied Sciences, Wyss Institute for Biologically Inspired Engineering PhD Students: Jeffrey Santoso, Joycelyn Yip, Andrew Petersen, Nathan Cho, Nethika Ariyasinghe, Davi Leite

3 The Heart: Structure and Function Heart Myocardium 50 µm Myocyte 5 cm Hierarchical spatial organization is essential for the heart to pump effectively Adapted from Knight, Grosberg, McCain, Cardiac Cytoarchitecture,

4 Deconstructing Heart Disease Causes: Acquired Common Features: Fibrosis E = kpa E > 50 kpa Cellular remodeling Extracellular matrix remodeling Changes in mechanical loading Inherited Common Complications: Ventricular remodeling Arrhythmias Inefficient metabolism Contractile deficits 4

5 Existing Models for Cardiac Disease Modeling Animal Models Conventional Cell Culture + Intact organism + Native physiology X Non-human X Limited control X Limited access X Low throughput X High cost + Experimental control + Human cells + High throughput + Low cost X Lacking native tissue structure X Lacking physical cues X Limited functional outputs

6 Design Parameters for Engineering Cardiac Disease Models Inputs: Cell demographics Cell genotype Cell/tissue architecture Matrix composition Matrix mechanics Matrix topography/ dimensionality Mechanical forces Technology: Modular Scalable Robust Quantitative Human-relevant Patient-specific Outputs: Gene/protein expression Cell/tissue morphology Metabolism Electrophysiology Contractility 6

7 Muscular Thin Films 1. Mask coverslip with tape and cut 2. Coat thermosensitive polymer and peel tape 3. Coat PDMS 4. Cut PDMS and micropattern 5. Seed myocytes 6. Record contractility Feinberg et al, Science Grosberg et al, Lab on a Chip Agarwal et al, Lab on a Chip 2013.

8 Muscular Thin Films 1. Mask coverslip with tape and cut 2. Coat thermosensitive polymer and peel tape 3. Coat PDMS 4. Cut PDMS and micropattern 5. Seed myocytes 6. Record contractility Feinberg et al, Science Grosberg et al, Lab on a Chip Agarwal et al, Lab on a Chip 2013.

9 Engineering Human-Relevant Cardiac Disease Models Dermal fibroblasts from a patient

10 Modeling an Inherited Cardiomyopathy on a Chip Barth Syndrome (BTH) Cardiomyopathy Mutation in Tafazzin (TAZ) enzyme TAZ processes cardiolipin, a lipid component of the inner mitochondrial membrane in striated muscle Pu lab: skin fibroblasts from healthy and Barth patients re-programmed into induced pluripotent stem cells (ipscs) differentiated into cardiac myocytes Prof. William Pu, Children s Hospital Boston Wildtype (WT) Cardiolipin precursor Cardiolipin Barth (BTH) Cardiolipin precursor Cardiolipin Dr. Gang Wang hipsc-derived cardiac myocytes recapitulate the mitochondrial phenotypes seen in patients Wang, McCain, et al, Nature Medicine, 2014.

11 Contractile Function of Patient ipsc-derived Cardiac Tissues Wildtype Patient: Wildtype + GFP modrna Barth Syndrome Patient: Barth + GFP modrna Barth Plus Rescue: Barth + TAZ modrna 1mm Wang, McCain, et al, Nature Medicine, Barth Syndrome hipsc-derived cardiac myocytes have reduced contractility, dependent on TAZ deficiency 11

12 Revealing Disease Mechanisms with Patient-Specific Heart on a Chip Reactive oxygen species (ROS) are a natural mitochondrial byproduct of metabolism One proposed mechanism for Barth syndrome is excessive buildup of ROS We treated Barth ips-derived cardiac myocytes with MitoTempo (MT), an ROS scavenger MitoTempo rescued contractile function Barth + vehicle Barth + ROS scavenger Wang, McCain, et al, Nature Medicine, By combining hipsc-derived cardiac myocytes with Heart on a Chip, we can reveal new disease mechanisms and identify therapeutic targets 12

13 Drug Screening with Patient-Specific Heart on a Chip Linoleic acid (LA) is a fatty acid precursor to cardiolipin, the deficient lipid in Barth syndrome Barth + vehicle Barth + Linoleic Acid Wang, McCain, et al, Nature Medicine, Contractility of Barth Syndrome hipsc-derived cardiac myocytes is rescued by cardiolipin precursors Potential therapeutic approach 13

14 Sarcomere Organization in Patient ipsc-derived Cardiac Myocytes A B C D Healthy myocytes were densely packed with aligned sarcomeres (A) Myocytes from Barth patients were sparse and poorly aligned (B) Sarcomere organization was rescued with TAZ transfection (C) but not activation of glycolysis (D) Bar = 10 µm BTH-H = Barth WT + GFP TAZ = tafazzin Galactose BTH + GFP Galactose BTH + TAZ Galactose BTH + GFP Glucose Sarcomere organization was rescued by TAZ transfection but not glucose Suggests mitochondria and sarcomeres have co-dependent structural relationships Wang, McCain, et al, Nature Medicine,

15 Establishing Interactions Between Sarcomeres and Mitochondria Extracellular Matrix Rigidity? Contractility Myofibril Architecture Mitochondria? Does extracellular matrix rigidity and/or myofibril architecture regulate mitochondrial function?

16 Tools for Measuring Oxygen Consumption In Vitro Seahorse Bioscience. How do we engineer cardiac tissues within cell culture microplates?

17 Engineering Cardiac Tissues within Microplates 5 mm 50 µm 50 µm 50 µm Leite et al, AJP Heart Davi Leite

18 Engineering Cardiac Tissues within Microplates DAPI Actin Sarcomeric α-actinin Bars = 50 µm Leite et al, AJP Heart 2017.

19 Oxygen Consumption Rates (OCR) in Engineered Cardiac Tissues Allen Andres & Roberta Gottlieb Leite et al, AJP Heart Cedars-Sinai

20 Co-Regulation of Mitochondrial Function by Matrix Elasticity & Tissue Alignment Baseline mitochondrial function: Scales with matrix rigidity Independent of tissue alignment Mitochondrial function in response to stress: Regulated by ECM elasticity ONLY in aligned tissues

21 Engineering µphysiological Models of Human Cardiac & Skeletal Muscle Disease Design Build Applications Test