Tenogenic differentiation of human MSCs induced by the topography of electrochemically aligned collagen threads

Abstract

Topographical cues from the extracellular microenvironment can influence cellular activity including proliferation and differentiation. Information on the effects of material topography on tenogenic differentiation of human mesenchymal stem cells (human MSCs) is limited. A methodology using the principles of isoelectric focusing has previously been developed in our laboratory to synthesize electrochemically aligned collagen (ELAC) threads that mimics the packing density, alignment and strength of collagen dense connective tissues. In the current study, human MSCs were cultured on ELAC and randomly-oriented collagen threads and the effect of collagen orientation on cell morphology, proliferation and tenogenic differentiation was investigated. The results indicate that higher rates of proliferation were observed on randomly oriented collagen threads compared to ELAC threads. On the other hand, tendon specific markers such as scleraxis, tenomodulin, tenascin-C and collagen-III were significantly increased on ELAC threads compared to randomly oriented collagen threads. Additionally, osteocalcin, a specific marker of bone differentiation was suppressed on ELAC threads. Previous studies have reported that BMP-12 is a key growth factor to induce tenogenic differentiation of human MSCs. To evaluate the synergistic effect of BMP-12 and collagen orientation, human MSCs were cultured on ELAC threads in culture medium supplemented with and without BMP-12. The results revealed that BMP-12 did not have an additional effect on the tenogenic differentiation of human MSCs on ELAC threads. Together, these results suggest that ELAC induces tenogenic differentiation of human MSCs by presenting an aligned and dense collagen substrate, akin to the tendon itself. In conclusion, ELAC has a significant potential to be used as a tendon replacement and in the development of an osteotendinous construct towards the regeneration of bone-tendon interfaces.

The past, present and future in scaffold-based tendon treatments

“…When their potential for spinal cord injuries was assessed, it became apparent that such materials not only promote directional neurite guidance, but also overcome inhibition by myelin associated glycoprotein [366]. In a tendon setting, these collagen fibres have been shown to promote bidirectional alignment and migration of tendon derived cells and to differentiate human BMSCs towards tenogenic lineage, even in the absence of biological signals [367,368]. Combinations of fibrous scaffolds that offer mechanical resilience and hydrogels systems that offer cell retention capacity have demonstrated improved biomechanics and functionality in preclinical models [369,370].…”

Harnessing magnetic-mechano actuation in regenerative medicine and tissue engineering

“…However, recent findings show that mechanotransduction is not restricted to cell surface receptors and adhesion, but can occur directly through the nucleus via phosphorylation of emerin [38]. In addition to stiffness, stem cell differentiation can be regulated by topographical cues [39][40][41][42]. Integrins also play a critical role in this process by mediating cell adhesion to micro-or nanoscale topographic features, resulting in the contraction of the cytoskeleton and activation of biochemical signalling pathways [43].…”

Substrate topography: A valuable in vitro tool, but a clinical red herring for in vivo tenogenesis

“…electro-spinning [26][27][28][29][30][31], fibre extrusion [32][33][34][35], isoelectric focusing [36,37] and imprinting [38][39][40]) have been at the forefront of scientific and technological research and innovation to recapitulate native tendon extracellular matrix (ECM) supramolecular assemblies. Although fibrous constructs (e.g.…”