Spatiotemporal control of cardiac anisotropy using dynamic nanotopographic cues

Abstract

Coordinated extracellular matrix spatiotemporal reorganization helps regulate cellular differentiation, maturation, and function in vivo, and is therefore vital for the correct formation, maintenance, and healing of complex anatomic structures. In order to evaluate the potential for cultured cells to respond to dynamic changes in their in vitro microenvironment, as they do in vivo, the collective behavior of primary cardiac muscle cells cultured on nanofabricated substrates with controllable anisotropic topographies was studied. A thermally induced shape memory polymer (SMP) was employed to assess the effects of a 90° transition in substrate pattern orientation on the contractile direction and structural organization of cardiomyocyte sheets. Cardiomyocyte sheets cultured on SMPs exhibited anisotropic contractions before shape transition. 48 hours after heat-induced shape transition, the direction of cardiomyocyte contraction reoriented significantly and exhibited a bimodal distribution, with peaks at ~ 45 and −45 degrees (P < 0.001). Immunocytochemical analysis highlighted the significant structural changes that the cells underwent in response to the shift in underlying topography. The presented results demonstrate that initial anisotropic nanotopographic cues do not permanently determine the organizational fate or contractile properties of cardiomyocytes in culture. Given the importance of surface cues in regulating primary and stem cell development, investigation of such tunable nanotopographies may have important implications for advancing cellular maturation and performance in vitro, as well as improving our understanding of cellular development in response to dynamic biophysical cues.

Dynamically tunable cell culture platforms for tissue engineering and mechanobiology

“…Mengsteab et al . recently reported that these PCL-SMP-based nanotopographic cues are capable of serving as instructive signals that dynamically regulate the structural and contractile properties of neonatal rat ventricular myocytes (NRVMs) into a well-defined anisotropic monolayer [162]. Indeed, the orthogonal transition of anisotropic nanogrooves could be used to directly manipulate the contractile direction of cardiac cell sheets (Figure 9B).…”

“…The kurtosis of contraction direction after shape transition decreases, and a 49 degree shift of the contraction angle peak is observed (kurtosis = 2.45, 0.31 before and after, respectively. *p < 0.001, n = 3, paired t-test) [162]. (C) Shape memory assisted dynamic microwrinkle display system.…”

Human iPSC-derived cardiomyocytes and tissue engineering strategies for disease modeling and drug screening

“…Parallel nano-grooves and nano-ridges help maintain the cell polarity and alignment important for organ development by providing contact guidance which influences the organization of microtubules, focal contacts, and actin filaments in parallel with the underlying topography (Kim et al, 2012b). Investigations with cardiomyocytes on dynamically shifting topographies demonstrate the capacity for such cells to reorient themselves in real-time, according to changes in substrate cues, mirroring cells’ capacity to remodel in vivo in response to damage or alterations in mechanical strain (Mengsteab et al, 2016). Similarly, cells cultured on ECM fibers and microgrooves aligned with electrical stimulation patterns have also shown increased elongation, alignment, and electrical functionality (Kim et al, 2010, Kim et al, 2013b) (Figure 3A–C).…”

Temporal Modulation of Stem Cell Activity Using Magnetoactive Hydrogels

“…In addition, although great care is usually given to the temporal regulation of chemical factors used in several protocols (during somatic cell reprogramming [27] for instance), there is no reason to assume that mechanical regulation is not just as important. In fact, a recent study utilizing tunable polymeric materials to study the effects of parameters such as anisotropic topgraphic cues [28] or stress relaxation [29] reveal highly dynamic cellular responses. Therefore, there is a need for in-vitro cell culture platforms with externally tunable mechanical properties in order to study the temporal effect of these parameters [30] .…”