Microfluidics-based optimization of neuroleukin-mediated regulation of articular chondrocyte proliferation

Abstract

Due to the low proliferative and migratory capacities of chondrocytes, cartilage repair remains a challenging clinical problem. Current therapeutic strategies for cartilage repair result in unsatisfactory outcomes. Autologous chondrocyte implantation (ACI) is a cell based therapy that relies on the in vitro expansion of healthy chondrocytes from the patient, during which proliferation-promoting factors are frequently used. Neuroleukin (NLK) is a multifunctional protein that possesses growth factor functions, and its expression has been associated with cartilage development and bone regeneration, however its direct role in chondrocyte proliferation remains to be fully elucidated. In the current study, the role of NLK in chondrocyte proliferation in vitro in addition to its potential to act as an exogenous factor during ACI was investigated. Furthermore, the concentration of NLK for in vitro chondrocyte culture was optimized using a microfluidic device. An NLK concentration of 12.85 ng/ml was observed to provide optimal conditions for the promotion of chondrocyte proliferation. Additionally, NLK stimulation resulted in an increase in type II collagen synthesis by chondrocytes, which is a cartilaginous secretion marker and associated with the phenotype of chondrocytes. Together these data suggest that NLK is able to promote cell proliferation and type II collagen synthesis during in vitro chondrocyte propagation, and thus may serve as an exogenous factor for ACI.

Progress of Microfluidic Hydrogel‐Based Scaffolds and Organ‐on‐Chips for the Cartilage Tissue Engineering

“…Future research projects may offer mechanistic insights into the NLK regulation of chondrocytes growth. [ 358 ] In an endeavor to design an OC unit‐on‐a‐chip model including functional cartilage and bone tissue units, Goldman et al. [ 159 ] developed a microfluidic chip incorporating bovine MSCs‐derived OC constructs.…”

A Progress Report and Roadmap for Microphysiological Systems and Organ-On-A-Chip Technologies to Be More Predictive Models in Human (Knee) Osteoarthritis

“…As the most recent advancement in the palette of 3D culture techniques, organ-on-a-chip (OOAC) and microphysiological systems (MPS) aim for an even better recapitulation of a native tissue-like environment, tissue architecture and cell-specific responses relevant to OA modeling by combining stem cell or patient-derived primary cell-based models for cartilage and synovium ( Fomby et al, 2010 ; Smeriglio et al, 2015 ; Tian et al, 2016 ; Li et al, 2017 ; Lin et al, 2019 ) as well as adipose ( Loskill et al, 2017 ) and bone-like tissues ( Mansoorifar et al, 2021 ; Nasello et al, 2021 ). In this context, microfluidic technologies can create an even more dynamic yet more controllable musculoskeletal disease microenvironment.…”

“…Moreover, the authors used their miniaturized drug screening tool to recover cartilage-specific OA-like inflammation responses with a treatment. Notably, to further investigate and approximate in vivo- like tissue conditions, increase of microfluidic construct diameter and volumes by twofold increased collagen and glycosaminoglycan biosynthesis as well as the corresponding dynamic construct modulus ( Tian et al, 2016 ). Both studies demonstrate well that the geometry and macroscopic dimensions of a construct influence the models’ diffusivity as well as topographical molecule gradients that in turn are vital to control parameters for organoid maturation and native tissue-like physiology.…”

“…Notably, computer numerical control (CNC) micromachining or hot embossing of hard polymer slides would bridge the gap between soft lithography and injection molding. Nonetheless, scalable and high potential state-of-the-art technologies to improve the functionality of organs-on-a-chip and microphysiological systems may include well-established approaches found mostly for lab-on-a-chip and micro-total-analysis (µTAS) systems including integrated microvalves, micropumps, and gradient generators to control the automated administration of fluids at the picolitre scale ( Unger et al, 2000 ; Frey et al, 2014 ; Tian et al, 2016 ; Rothbauer et al, 2019 ). To further improve sample throughput, a combination of gravity-driven pumpless bidirectional fluid handling technology ( Sung et al, 2010 ; Esch et al, 2016 ) with robotics ( Novak et al, 2020 ) may also be a high potential candidate.…”

Translational Application of Microfluidics and Bioprinting for Stem Cell-Based Cartilage Repair

“…Noticeably, the results of this study demonstrated that the developed model allows replicating the 3D expansion step occurring during the early stages of limb development, overcoming one of the main limitations of other 3D models, such as macropellets, which experience a reduction in cell number over time due to the formation of a necrotic core [ 54 ]. The use of SDGs has been also implemented in microfluidic platforms designed and exploited to select the most suitable concentration and/or combination of growth factors to favor articular chondrocyte proliferation, either in monolayer culture [ 55 ] or hydrogel-based culture [ 56 ]. The low number of cells that can be obtained from patients' biopsies is one of the main limiting factors in ACI procedures, and hence, the optimization of the protocol for chondrocyte expansion represents a crucial step to improve the outcome of this clinical approach.…”