Publications

2017
98 -, Lind JU, Busbee TA, Valentine AD, Pasqualini FS, Yuan H, Yadid M, Park SJ, Kotikian A, Nesmith AP, Campbell PH, Vlassak JJ, Lewis JA, and Parker KK. 2017. “Instrumented cardiac microphysiological devices via multimaterial three-dimensional printing.” Nature Materials, 16, 3, Pp. 303-308. Publisher's VersionAbstract
Biomedical research has relied on animal studies and conventional cell cultures for decades. Recently, microphysiological systems (MPS), also known as organs-on-chips, that recapitulate the structure and function of native tissues in vitro, have emerged as a promising alternative1. However, current MPS typically lack integrated sensors and their fabrication requires multi-step lithographic processes2. Here, we introduce a facile route for fabricating a new class of instrumented cardiac microphysiological devices via multimaterial three-dimensional (3D) printing. Specifically, we designed six functional inks, based on piezo-resistive, high-conductance, and biocompatible soft materials that enable integration of soft strain gauge sensors within micro-architectures that guide the self-assembly of physio-mimetic laminar cardiac tissues. We validated that these embedded sensors provide non-invasive, electronic readouts of tissue contractile stresses inside cell incubator environments. We further applied these devices to study drug responses, as well as the contractile development of human stem cell-derived laminar cardiac tissues over four weeks.
Instrumented cardiac microphysiological devices via multimaterial three-dimensional printing
97 -, Capulli AK, Emmert MY, Pasqualini FS, Kehl D, Caliskan E, Lind JU, Sheehy SP, Park SJ, Ahn S, Weber B, Goss JA, Hoerstrup SP, and Parker KK. 2017. “JetValve: Rapid manufacturing of biohybrid scaffolds for biomimetic heart valve replacement.” Biomaterials, 133, Pp. 229-241. Publisher's VersionAbstract
Tissue engineered scaffolds have emerged as a promising solution for heart valve replacement because of their potential for regeneration. However, traditional heart valve tissue engineering has relied on resource-intensive, cell-based manufacturing, which increases cost and hinders clinical translation. To overcome these limitations, in situ tissue engineering approaches aim to develop scaffold materials and manufacturing processes that elicit endogenous tissue remodeling and repair. Yet despite recent advances in synthetic materials manufacturing, there remains a lack of cell-free, automated approaches for rapidly producing biomimetic heart valve scaffolds. Here, we designed a jet spinning process for the rapid and automated fabrication of fibrous heart valve scaffolds. The composition, multiscale architecture, and mechanical properties of the scaffolds were tailored to mimic that of the native leaflet fibrosa and assembled into three dimensional, semilunar valve structures. We demonstrated controlled modulation of these scaffold parameters and show initial biocompatibility and functionality in vitro. Valves were minimally-invasively deployed via transapical access to the pulmonary valve position in an ovine model and shown to be functional for 15 h.
JetValve: Rapid manufacturing of biohybrid scaffolds for biomimetic heart valve replacement
96 -, Yuan H, Marzban B, and Parker KK. 2017. “Myofibrils in Cardiomyocytes Tend to Assemble Along the Maximal Principle Stress Directions.” Journal of Biomechanical Engineering, 139, 12, Pp. 1210101–1210108. Publisher's VersionAbstract
The mechanisms underlying the spatial organization of self-assembled myofibrils in cardiac tissues remain incompletely understood. By modeling cells as elastic solids under active cytoskeletal contraction, we found a good correlation between the predicted maximal principal stress directions and the in vitro myofibril orientations in individual cardiomyocytes. This implies that actomyosin fibers tend to assemble along the maximal tensile stress (MTS) directions. By considering the dynamics of focal adhesion and myofibril formation in the model, we showed that different patterns of myofibril organizations in mature versus immature cardiomyocytes can be explained as the consequence of the different levels of force-dependent remodeling of focal adhesions. Further, we applied the mechanics model to cell pairs and showed that the myofibril organizations can be regulated by a combination of multiple factors including cell shape, cell–substrate adhesions, and cell–cell adhesions. This mechanics model can guide the rational design in cardiac tissue engineering where recapitulating in vivo myofibril organizations is crucial to the contractile function of the heart.
Myofibrils in Cardiomyocytes Tend to Assemble Along the Maximal Principle Stress Directions
95 -, Dauth S, Maoz BM, Sheehy SP, Hemphill MA, Murty T, Macedonia MK, Greer AM, Budnik B, and Parker KK. 2017. “Neurons derived from different brain regions are inherently different in vitro: A novel multiregional brain-on-a-chip.” Journal of Neurophysiology, 117, 3, Pp. 1320-1341. Publisher's VersionAbstract
Brain in vitro models are critically important to developing our understanding of basic nervous system cellular physiology, potential neurotoxic effects of chemicals, and specific cellular mechanisms of many disease states. In this study, we sought to address key shortcomings of current brain in vitro models: the scarcity of comparative data for cells originating from distinct brain regions and the lack of multiregional brain in vitro models. We demonstrated that rat neurons from different brain regions exhibit unique profiles regarding their cell composition, protein expression, metabolism, and electrical activity in vitro. In vivo, the brain is unique in its structural and functional organization, and the interactions and communication between different brain areas are essential components of proper brain function. This fact and the observation that neurons from different areas of the brain exhibit unique behaviors in vitro underline the importance of establishing multiregional brain in vitro models. Therefore, we here developed a multiregional brain-on-a-chip and observed a reduction of overall firing activity, as well as altered amounts of astrocytes and specific neuronal cell types compared with separately cultured neurons. Furthermore, this multiregional model was used to study the effects of phencyclidine, a drug known to induce schizophrenia-like symptoms in vivo, on individual brain areas separately while monitoring downstream effects on interconnected regions. Overall, this work provides a comparison of cells from different brain regions in vitro and introduces a multiregional brain-on-a-chip that enables the development of unique disease models incorporating essential in vivo features.NEW & NOTEWORTHY Due to the scarcity of comparative data for cells from different brain regions in vitro, we demonstrated that neurons isolated from distinct brain areas exhibit unique behaviors in vitro. Moreover, in vivo proper brain function is dependent on the connection and communication of several brain regions, underlining the importance of developing multiregional brain in vitro models. We introduced a novel brain-on-a-chip model, implementing essential in vivo features, such as different brain areas and their functional connections.
Neurons derived from different brain regions are inherently different in vitro: A novel multiregional brain-on-a-chip
94 -, Pasqualini FS, Emmert MY, Parker KK, and Hoerstrup SP. 2017. “Organ Chips: Quality Assurance Systems in Regenerative Medicine.” Clinical Pharmacology & Therapeutics, 101, 1, Pp. 31-34. Publisher's VersionAbstract
A class of novel therapies leverages regenerative cell types in disease microenvironments.[1] This complex interplay challenges established good manufacturing practices, as standards and analytical tools to measure regenerative potency are missing.[2] That is, we can build the product right, but we do not know if we are building the right product. Here, we suggest that organ-chips, biomimetic in-vitro phenotyping platforms,[3,4] can serve as key quality assurance systems in regenerative medicine.[1,2,5]
Organ Chips: Quality Assurance Systems in Regenerative Medicine
93 -, Maoz BM, Herland A, Henry OYF, Leineweber WD, Yadid M, Doyle J, Mannix R, Kujala VJ, Fitzgerald EA, Parker KK, and Ingber DE. 2017. “Organs-on-Chips with combined multi-electrode array and transepithelial electrical resistance measurement capabilities.” Lab Chip, 17, 13, Pp. 2294-2302. Publisher's VersionAbstract
Here we demonstrate that microfluidic cell culture devices, known as Organs-on-a-Chips can be fabricated with multifunctional, real-time, sensing capabilities by integrating both multi-electrode arrays (MEAs) and electrodes for transepithelial electrical resistance (TEER) measurements into the chips during their fabrication. To prove proof-of-concept, simultaneous measurements of cellular electrical activity and tissue barrier function were carried out in a dual channel, endothelialized, heart-on-a-chip device containing human cardiomyocytes and a channel-separating porous membrane covered with a primary human endothelial cell monolayer. These studies confirmed that the TEER–MEA chip can be used to simultaneously detect dynamic alterations of vascular permeability and cardiac function in the same chip when challenged with the inflammatory stimulus tumor necrosis factor alpha (TNF-α) or the cardiac targeting drug isoproterenol. Thus, this Organ Chip with integrated sensing capability may prove useful for real-time assessment of biological functions, as well as response to therapeutics.
Organs-on-Chips with combined multi-electrode array and transepithelial electrical resistance measurement capabilities
92 -, Gonzalez GM, MacQueen LA, Lind JU, Fitzgibbons SA, Chantre CO, Huggler I, Golecki HM, Goss JA, and Parker KK. 2017. “Production of synthetic, para-aramid and biopolymer nanofibers by immersion rotary jet-spinning.” Macromolecular Materials and Engineering, 302, 1, Pp. 1600365. Publisher's VersionAbstract
Nanofiber production platforms commonly rely on volatile carrier solvents or high voltages. Production of nanofibers comprised of charged polymers or polymers requiring nonvolatile solvents thus typically requires customization of spinning setup and polymer dope. In severe cases, these challenges can hinder fiber formation entirely. Here, a versatile system is presented which addresses these challenges by employing centrifugal force to extrude polymer dope jet through an air gap, into a flowing precipitation bath. This voltage-free approach ensures that nanofiber solidification occurs in liquid, minimizing surface tension instability that results in jet breakup and fiber defects. In addition, nanofibers of controlled size and morphology can be fabricated by tuning spinning parameters including air gap length, spinning speed, polymer concentration, and bath composition. To demonstrate the versatility of our platform, para-aramid (e.g., Kevlar) and biopolymer (e.g., DNA, alginate) nanofibers are produced that cannot be readily produced using standard nanofiber production methods.
Production of synthetic, para-aramid and biopolymer nanofibers by immersion rotary jet-spinning
91 -, Emmert MY, Wolint P, Jakab A, Sheehy SP, Pasqualini FS, Nguyen TD, Hilbe M, Seifert B, Weber B, Brokopp CE, Macejovska D, Caliskan E, Eckardstein von A, Schwartlander R, Vogel V, Falk V, Parker KK, Gyöngyösi M, and Hoerstrup SP. 2017. “Safety and efficacy of cardiopoietic stem cells in the treatment of post-infarction left-ventricular dysfunction – From cardioprotection to functional repair in a translational pig infarction model.” Biomaterials, 122, Pp. 48-62. Publisher's VersionAbstract
To date, clinical success of cardiac cell-therapies remains limited. To enhance the cardioreparative properties of stem cells, the concept of lineage-specification through cardiopoietic-guidance has been recently suggested. However, so far, only results from murine studies and from a clinical pilot-trial in chronic heart-failure (CHF) are available, while systematic evidence of its therapeutic-efficacy is still lacking. Importantly, also no data from large animals or for other indications are available. Therefore, we here investigate the therapeutic-efficacy of human cardiopoietic stem cells in the treatment of post-infarction LV-dysfunction using a translational pig-model. Using growth-factor priming, lineage-specification of human bone-marrow derived MSCs was achieved to generate cardiopoietic stem cells according to GMP-compliant protocols. Thereafter, pigs with post-infarction LV-dysfunction (sub-acute phase;1-month) were randomized to either receive transcatheter NOGA 3D electromechanical-mapping guided intramyocardial transplantation of cardiopoietic cells or saline (control). After 30days, cardiac MRI (cMRI) was performed for functional evaluation and in-vivo cell-tracking. This approach was coupled with a comprehensive post-mortem cell-fate and mode-of-repair analysis. Cardiopoietic cell therapy was safe and ejection-fraction was significantly higher when compared to controls (p = 0.012). It further prevented maladaptive LV-remodeling and revealed a significantly lower relative and total infarct-size (p = 0.043 and p = 0.012). As in-vivo tracking and post-mortem analysis displayed only limited intramyocardial cardiopoietic cell-integration, the significant induction of neo-angiogenesis (∼40% higher; p = 0.003) and recruitment of endogenous progenitors (∼2.5x higher; p = 0.008) to the infarct border-zone appeared to be the major modes-of-repair. This is the first report using a pre-clinical large animal-model to demonstrate the safety and efficacy of cardiopoietic stem cells for the treatment of post-infarction LV-dysfunction to prevent negative LV-remodeling and subsequent CHF. It further provides insight into post-delivery cardiopoietic cell-fate and suggests the mechanisms of cardiopoietic cell-induced cardiac-repair. The adoption of GMP-/GLP-compliant methodologies may accelerate the translation into a phase-I clinical-trial in patients with post-ischemic LV-dysfunction broadening the current indication of this interesting cell-type.
Safety and efficacy of cardiopoietic stem cells in the treatment of post-infarction left-ventricular dysfunction – From cardioprotection to functional repair in a translational pig infarction model
90 -, Sheehy SP, Grosberg A, Qin P, Behm DJ, Ferrier JP, Eagleson MA, Nesmith AP, Krull D, Falls JG, Campbell PH, McCain ML, Willette RN, Hu E, and Parker KK. 2017. “Toward improved myocardial maturity in an organ-on-chip platform with immature cardiac myocytes.” Experimental Biology and Medicine, 242, 17, Pp. 1643-1656. Publisher's VersionAbstract
In vitro studies of cardiac physiology and drug response have traditionally been performed on individual isolated cardiomyocytes or isotropic monolayers of cells that may not mimic desired physiological traits of the laminar adult myocardium. Recent studies have reported a number of advances to Heart-on-a-Chip platforms for the fabrication of more sophisticated engineered myocardium, but cardiomyocyte immaturity remains a challenge. In the anisotropic musculature of the heart, interactions between cardiac myocytes, the extracellular matrix (ECM), and neighboring cells give rise to changes in cell shape and tissue architecture that have been implicated in both development and disease. We hypothesized that engineered myocardium fabricated from cardiac myocytes cultured in vitro could mimic the physiological characteristics and gene expression profile of adult heart muscle. To test this hypothesis, we fabricated engineered myocardium comprised of neonatal rat ventricular myocytes with laminar architectures reminiscent of that observed in the mature heart and compared their sarcomere organization, contractile performance characteristics, and cardiac gene expression profile to that of isolated adult rat ventricular muscle strips. We found that anisotropic engineered myocardium demonstrated a similar degree of global sarcomere alignment, contractile stress output, and inotropic concentration-response to the β-adrenergic agonist isoproterenol. Moreover, the anisotropic engineered myocardium exhibited comparable myofibril related gene expression to muscle strips isolated from adult rat ventricular tissue. These results suggest that tissue architecture serves an important developmental cue for building in vitro model systems of the myocardium that could potentially recapitulate the physiological characteristics of the adult heart. Impact statement With the recent focus on developing in vitro Organ-on-Chip platforms that recapitulate tissue and organ-level physiology using immature cells derived from stem cell sources, there is a strong need to assess the ability of these engineered tissues to adopt a mature phenotype. In the present study, we compared and contrasted engineered tissues fabricated from neonatal rat ventricular myocytes in a Heart-on-a-Chip platform to ventricular muscle strips isolated from adult rats. The results of this study support the notion that engineered tissues fabricated from immature cells have the potential to mimic mature tissues in an Organ-on-Chip platform.
Toward improved myocardial maturity in an organ-on-chip platform with immature cardiac myocytes
2016
89 -, Capulli AK, MacQueen LA, O’Connor BB, Dauth S, and Parker KK. 2016. “Acute pergolide exposure stiffens engineered valve interstitial cell tissues and reduced contractility in vitro.” Cardiovascular Pathology, 25, 4, Pp. 316-324. Publisher's VersionAbstract
Medications based on ergoline-derived dopamine and serotonin agonists are associated with off-target toxicities that include valvular heart disease (VHD). Reports of drug-induced VHD resulted in the withdrawal of appetite suppressants containing fenfluramine and phentermine from the US market in 1997 and pergolide, a Parkinson's disease medication, in 2007. Recent evidence suggests that serotonin receptor activity affected by these medications modulates cardiac valve interstitial cell activation and subsequent valvular remodeling, which can lead to cardiac valve fibrosis and dysfunction similar to that seen in carcinoid heart disease. Failure to identify these risks prior to market and continued use of similar drugs reaffirm the need to improve preclinical evaluation of drug-induced VHD. Here, we present two complimentary assays to measure stiffness and contractile stresses generated by engineered valvular tissues in vitro. As a case study, we measured the effects of acute (24 h) pergolide exposure to engineered porcine aortic valve interstitial cell (AVIC) tissues. Pergolide exposure led to increased tissue stiffness, but it decreased both basal and active contractile tone stresses generated by AVIC tissues. Pergolide exposure also disrupted AVIC tissue organization (i.e., tissue anisotropy), suggesting that the mechanical properties and contractile functionality of these tissues are governed by their ability to maintain their structure. We expect further use of these assays to identify off-target drug effects that alter the phenotypic balance of AVICs, disrupt their ability to maintain mechanical homeostasis, and lead to VHD.
Acute pergolide exposure stiffens engineered valve interstitial cell tissues and reduced contractility in vitro
88 -, Horton RE, Yadid M, McCain, ML, Sheehy SP, Pasqualini FS, Park SJ, Cho A, Campbell P, and Parker KK. 2016. “Angiotensin II Induced Cardiac Dysfunction on a Chip.” PLOS ONE, 1, 1, Pp. e0146415. Publisher's VersionAbstract
In vitro disease models offer the ability to study specific systemic features in isolation to better understand underlying mechanisms that lead to dysfunction. Here, we present a cardiac dysfunction model using angiotensin II (ANG II) to elicit pathological responses in a heart-on-a-chip platform that recapitulates native laminar cardiac tissue structure. Our platform, composed of arrays of muscular thin films (MTF), allows for functional comparisons of healthy and diseased tissues by tracking film deflections resulting from contracting tissues. To test our model, we measured gene expression profiles, morphological remodeling, calcium transients, and contractile stress generation in response to ANG II exposure and compared against previous experimental and clinical results. We found that ANG II induced pathological gene expression profiles including over-expression of natriuretic peptide B, Rho GTPase 1, and T-type calcium channels. ANG II exposure also increased proarrhythmic early after depolarization events and significantly reduced peak systolic stresses. Although ANG II has been shown to induce structural remodeling, we control tissue architecture via microcontact printing, and show pathological genetic profiles and functional impairment precede significant morphological changes. We assert that our in vitro model is a useful tool for evaluating tissue health and can serve as a platform for studying disease mechanisms and identifying novel therapeutics.
Angiotensin II Induced Cardiac Dysfunction on a Chip.
87 -, Aratyn-Schaus Y, Pasqualini FS, Yuan H, McCain ML, Ye GJ, Sheehy SP, Campbell PH, and Parker KK. 2016. “Coupling primary and stem cell-derived cardiomyocytes in an in vitro model of cardiac cell therapy.” Journal of Cell Biology, 212, 4, Pp. 389–397. Publisher's VersionAbstract
The efficacy of cardiac cell therapy depends on the integration of existing and newly formed cardiomyocytes. Here, we developed a minimal in vitro model of this interface by engineering two cell microtissues (μtissues) containing mouse cardiomyocytes, representing spared myocardium after injury, and cardiomyocytes generated from embryonic and induced pluripotent stem cells, to model newly formed cells. We demonstrated that weaker stem cell–derived myocytes coupled with stronger myocytes to support synchronous contraction, but this arrangement required focal adhesion-like structures near the cell–cell junction that degrade force transmission between cells. Moreover, we developed a computational model of μtissue mechanics to demonstrate that a reduction in isometric tension is sufficient to impair force transmission across the cell–cell boundary. Together, our in vitro and in silico results suggest that mechanotransductive mechanisms may contribute to the modest functional benefits observed in cell-therapy studies by regulating the amount of contractile force effectively transmitted at the junction between newly formed and spared myocytes.
Coupling primary and stem cell-derived cardiomyocytes in an in vitro model of cardiac cell therapy
86 -, Dauth S, Grevesse T, Pantazopoulos H, Campbell PH, Maoz BM, Berretta S, and Parker KK. 2016. “Extracellular matrix protein expression is brain region dependent.” The Journal of Comparative Neurology, 524, 7, Pp. 1309-36. Publisher's VersionAbstract
In the brain, extracellular matrix (ECM) components form networks that contribute to structural and functional diversity. Maladaptive remodeling of ECM networks has been reported in neurodegenerative and psychiatric disorders, suggesting that the brain microenvironment is a dynamic structure. A lack of quantitative information about ECM distribution in the brain hinders an understanding of region-specific ECM functions and the role of ECM in health and disease. We hypothesized that each ECM protein as well as specific ECM structures, such as perineuronal nets (PNNs) and interstitial matrix, are differentially distributed throughout the brain, contributing to the unique structure and function in the various regions of the brain. To test our hypothesis, we quantitatively analyzed the distribution, colocalization, and protein expression of aggrecan, brevican, and tenascin-R throughout the rat brain utilizing immunohistochemistry and mass spectrometry analysis and assessed the effect of aggrecan, brevican, and/or tenascin-R on neurite outgrowth in vitro. We focused on aggrecan, brevican, and tenascin-R as they are especially expressed in the mature brain, and have established roles in brain development, plasticity, and neurite outgrowth. The results revealed a differentiated distribution of all three proteins throughout the brain and indicated that their presence significantly reduces neurite outgrowth in a 3D in vitro environment. These results underline the importance of a unique and complex ECM distribution for brain physiology and suggest that encoding the distribution of distinct ECM proteins throughout the brain will aid in understanding their function in physiology and in turn assist in identifying their role in disease. J. Comp. Neurol. 524:1309-1336, 2016. © 2016 Wiley Periodicals, Inc.
Extracellular matrix protein expression is brain region dependent
85 -, Chal J, Tanoury ZA, Hestin M, Gobert B, Cherrier T Aivio S, Hick A, Nesmith AP, Parker KK, and Pourquié O. 2016. “Generation of human muscle fibers and satellite-like cells from human pluripotent stem cells in vitro.” Nature Protocols 11 (10), Pp. 1833-50. Publisher's VersionAbstract
Progress toward finding a cure for muscle diseases has been slow because of the absence of relevant cellular models and the lack of a reliable source of muscle progenitors for biomedical investigation. Here we report an optimized serum-free differentiation protocol to efficiently produce striated, millimeter-long muscle fibers together with satellite-like cells from human pluripotent stem cells (hPSCs) in vitro. By mimicking key signaling events leading to muscle formation in the embryo, in particular the dual modulation of Wnt and bone morphogenetic protein (BMP) pathway signaling, this directed differentiation protocol avoids the requirement for genetic modifications or cell sorting. Robust myogenesis can be achieved in vitro within 1 month by personnel experienced in hPSC culture. The differentiating culture can be subcultured to produce large amounts of myogenic progenitors amenable to numerous downstream applications. Beyond the study of myogenesis, this differentiation method offers an attractive platform for the development of relevant in vitro models of muscle dystrophies and drug screening strategies, as well as providing a source of cells for tissue engineering and cell therapy approaches.
Generation of human muscle fibers and satellite-like cells from human pluripotent stem cells in vitro
84 -, Nesmith AP, Wagner MA, Pasqualini FS, O’Connor BB, Pincus MJ, August PR, and Parker KK. 2016. “A human in vitro model of Duchenne muscular dystrophy muscle formation and contractility.” The Journal of Cell Biology, 215, 1, Pp. 47-56. Publisher's VersionAbstract
Tongue weakness, like all weakness in Duchenne muscular dystrophy (DMD), occurs as a result of contraction-induced muscle damage and deficient muscular repair. Although membrane fragility is known to potentiate injury in DMD, whether muscle stem cells are implicated in deficient muscular repair remains unclear. We hypothesized that DMD myoblasts are less sensitive to cues in the extracellular matrix designed to potentiate structure–function relationships of healthy muscle. To test this hypothesis, we drew inspiration from the tongue and engineered contractile human muscle tissues on thin films. On this platform, DMD myoblasts formed fewer and smaller myotubes and exhibited impaired polarization of the cell nucleus and contractile cytoskeleton when compared with healthy cells. These structural aberrations were reflected in their functional behavior, as engineered tongues from DMD myoblasts failed to achieve the same contractile strength as healthy tongue structures. These data suggest that dystrophic muscle may fail to organize with respect to extracellular cues necessary to potentiate adaptive growth and remodeling.
A human in vitro model of Duchenne muscular dystrophy muscle formation and contractility
90 -, Kujala VJ, Pasqualini FS, Goss JA, Nawroth JC, and Parker KK. 2016. “Laminar ventricular myocardium on a microelectrode array-based chip.” Journal of Materials Chemistry B, 4, 20, Pp. 3534-3543. Publisher's VersionAbstract
Pharmaceutical screening based on human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and multi electrode arrays (MEAs) have been proposed as a complementary method for electrophysiological safety and efficacy assessment in drug discovery and development. Contrary to animal models, these cells offer a human genetic background but, at present, fail to recapitulate the mechanical and structural properties of the native human myocardium. Here, we report that topographical cues on soft micromolded gelatin can coax hiPSC-CMs to form laminar cardiac tissues that resemble the native architecture of the heart. Importantly, using this method we were able to record tissue-level electrophysiological responses with a commercially available MEA setup. To validate this platform, we recorded cardiac field potentials at baseline and after pharmacological interventions with a β-adrenergic agonist (isoproterenol). Further, we tested the ability of our system to predict the response of laminar human cardiac tissues to a cardiotoxic pro-drug (terfenadine) and its non-cardiotoxic metabolite (fexofenadine). Finally, we integrated our platform with microfluidic components to build a heart-on-a-chip system that can be fluidically linked with other organs-on-chips in the future.
83 -, Benam KH, Novak R, Nawroth J, Hirano-Kobayashi M, Ferrante TC, Choe Y, Prantil-Baun R, Weaver JC, Bahinski A, Parker KK, and Ingber DE. 2016. “Matched-Comparative Modeling of Normal and Diseased Human Airway Responses Using a Microengineered Breathing Lung Chip.” Cell Systems, 3, 5, Pp. 456-466. Publisher's VersionAbstract
Smoking represents a major risk factor for chronic obstructive pulmonary disease (COPD), but it is difficult to characterize smoke-induced injury responses under physiological breathing conditions in humans due to patient-to-patient variability. Here, we show that a small airway-on-a-chip device lined by living human bronchiolar epithelium from normal or COPD patients can be connected to an instrument that "breathes" whole cigarette smoke in and out of the chips to study smoke-induced pathophysiology in vitro. This technology enables true matched comparisons of biological responses by culturing cells from the same individual with or without smoke exposure. These studies led to identification of ciliary micropathologies, COPD-specific molecular signatures, and epithelial responses to smoke generated by electronic cigarettes. The smoking airway-on-a-chip represents a tool to study normal and disease-specific responses of the human lung to inhaled smoke across molecular, cellular and tissue-level responses in an organ-relevant context.
Matched-Comparative Modeling of Normal and Diseased Human Airway Responses Using a Microengineered Breathing Lung Chip
82 -, Pasqualini FS, Nesmith AP, Horton RE, Sheehy SP, and Parker KK. 2016. “Mechanotransduction and Metabolism in Cardiomyocyte Microdomains.” BioMed Research International, 2016, 4081638. Publisher's VersionAbstract
Efficient contractions of the left ventricle are ensured by the continuous transfer of adenosine triphosphate (ATP) from energy production sites, the mitochondria, to energy utilization sites, such as ionic pumps and the force-generating sarcomeres. To minimize the impact of intracellular ATP trafficking, sarcomeres and mitochondria are closely packed together and in proximity with other ultrastructures involved in excitation-contraction coupling, such as t-tubules and sarcoplasmic reticulum junctions. This complex microdomain has been referred to as the intracellular energetic unit. Here, we review the literature in support of the notion that cardiac homeostasis and disease are emergent properties of the hierarchical organization of these units. Specifically, we will focus on pathological alterations of this microdomain that result in cardiac diseases through energy imbalance and posttranslational modifications of the cytoskeletal proteins involved in mechanosensing and transduction.
Mechanotransduction and Metabolism in Cardiomyocyte Microdomains
81 -, Pope BD, Warren CR, Parker KK, and Cowan CA. 2016. “Microenvironmental control of adipocyte fate and function.” Trends in Cell Biology, 26, 10, Pp. 745-55. Publisher's Version Microenvironmental control of adipocyte fate and function
80 -, Park SJ, Gazzola M, Park KS, Park S, DiSanto V, Blevins EL, Lind JU, Campbell PH, Dauth S, Capulli AK, Pasqualini FS, Ahn S, Cho A, Yuan H, Maoz BM, Vijaykumar R, Choi JW, Deisseroth K, Lauder GV, Mahadevan L, and Parker KK. 2016. “Phototactic guidance of a tissue-engineered soft-robotic ray.” Science, 353, 6295, Pp. 158-162. Publisher's VersionAbstract
Inspired by the relatively simple morphological blueprint provided by batoid fish such as stingrays and skates, we create a biohybrid system that enables an artificial animal, a tissue-engineered ray, to swim and phototactically follow a light cue. By patterning dissociated rat cardiac myocytes on an elastomeric body enclosing a microfabricated gold skeleton, we replicated fish morphology at one-tenth scale and captured basic fin deflection patterns of batoid fish. Optogenetics allows for phototactic guidance, steering and turning maneuvers. Optical stimulation induced sequential muscle activation via serpentine patterned muscle circuits leading to coordinated undulatory swimming. The speed and direction of the ray was controlled by modulating light frequency and by independently eliciting right and left fins, allowing the biohybrid machine to maneuver through an obstacle course. (125/125 max)
Phototactic guidance of a tissue-engineered soft-robotic ray

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