Buchowski, J. M. | Search bioRxiv

bioRxiv2024

IGF-1 Peptide Mimetic-functionalized Hydrogels Enhance MSC Survival and Immunomodulatory Activity

Human mesenchymal stem cells (MSCs) have demonstrated promise when delivered to damaged tissue or tissue defects for their cytokine secretion and inflammation modulation behaviors that can promote repair. Insulin-like growth factor 1 (IGF-1) has been shown to augment MSCs viability and survival and promote their secretion of cytokines that signal to endogenous cells, in the treatment of myocardial infarction, wound healing, and age-related diseases. Biomaterial cell carriers can be functionalized with growth factor-mimetic peptides (i.e. IGF-1 mimicking peptides) to enhance MSC function while promoting cell retention and minimizing off-target effects seen with direct administration of soluble growth factors. Here, we functionalized alginate hydrogels with three distinct IGF-1 peptide mimetics and the integrin-binding peptide, cyclic RGD. One IGF-1 peptide mimetic (IGM-3) in combination with integrin ligand was found to activate Akt and ERK1/2 signaling and support survival of serum-deprived MSCs. MSCs encapsulated in alginate hydrogels that presented both IGM-3 and cRGD showed a significant reduction in pro-inflammatory cytokine secretion when challenged with interleukin-1{beta}. Finally, MSCs cultured within the cRGD/IGM-3 hydrogels were able to blunt pro-inflammatory gene expression of human primary cells from degenerated intervertebral discs. These studies indicate the potential to leverage cell adhesive and IGF-1 growth factor peptide mimetics together to control therapeutic secretory behavior of MSCs. Significance StatementInsulin-like growth factor 1 (IGF-1) plays a multifaceted role in stem cell biology and may promote proliferation, survival, migration, and immunomodulation for MSCs. In this study, we functionalized alginate hydrogels with integrin-binding and IGF-1 peptide mimetics to investigate their impact on MSC function. Encapsulating MSCs in the dual peptide (cRGD/IGM-3) hydrogels enhanced their ability to reduce inflammatory cytokine production and promote anti-inflammatory gene expression in cells from degenerative human intervertebral discs exposed to proteins secreted by the MSC. This approach suggests a new way to retain and augment MSC functionality using IGF-1 peptide mimetics, offering an alternative to co-delivery of cells and high dose soluble growth factors for tissue repair and immune-system modulation.

bioengineering↗

bioRxiv2021

Engineered Peptide-Functionalized Hydrogels Modulate the RNA Transcriptome of Human Nucleus Pulposus Cells In Vitro

Degeneration and aging of the nucleus pulposus (NP) of the intervertebral disc (IVD) is accompanied by alterations in NP cell phenotype marked by a shift towards a fibroblast-like, catabolic state. We have recently demonstrated an ability to manipulate the phenotype of human adult degenerative NP cells through 2D culture upon poly(ethylene glycol) (PEG) based hydrogels dually functionalized with integrin- and syndecan-binding laminin-mimetic peptides (LMPs). In the present study, we sought to understand the transcriptomic changes elicited through NP cell interactions with the LMP-functionalized hydrogel system (LMP gel) by examining targets of interest a priori and by conducting unbiased analysis to identify novel mechanosensitive targets. The results of gene specific analysis demonstrated that the LMP gel promoted adult degenerative NP cells to upregulate 148 genes including several NP markers (e.g. NOG and ITGA6) and downregulate 277 genes, namely several known fibroblastic markers. Additionally, 13 genes associated with G protein-coupled receptors, many of which are known drug targets, were identified as differentially regulated following culture upon the gel. Furthermore, through gene set enrichment analysis we identified over 700 pathways enriched amongst the up- and downregulated genes including pathways related to cell differentiation, notochord morphogenesis, and intracellular signaling. Together these findings demonstrate the global mechanobiological effects induced by the LMP gel and confirm the ability of this substrate to modulate NP cell phenotype.

cell biology↗