Paracrine signals influence patterns of fibrocartilage differentiation in a lyophilized gelatin hydrogel for applications in rotator cuff repair

Biomater Sci. 2024 Sep 10;12(18):4806-4822. doi: 10.1039/d4bm00543k.

Abstract

Rotator cuff injuries present a clinical challenge for repair due to current limitations in functional regeneration of the native tendon-to-bone enthesis. A biomaterial that can regionally instruct unique tissue-specific phenotypes offers potential to promote enthesis repair. We have recently demonstrated the mechanical benefits of a stratified triphasic biomaterial made up of tendon- and bone-mimetic collagen scaffold compartments connected via a continuous hydrogel, and we now explore the potential of a biologically favorable enthesis hydrogel for this application. Here we report in vitro behavior of human mesenchymal stem cells (hMSCs) within thiolated gelatin (Gel-SH) hydrogels in response to chondrogenic stimuli as well as paracrine signals derived from MSC-seeded bone and tendon scaffold compartments. Chondrogenic differentiation media promoted upregulation of cartilage and entheseal fibrocartilage matrix markers COL2, COLX, and ACAN as well as the enthesis-associated transcription factors SCX, SOX9, and RUNX2 in hMSCs within Gel-SH. Similar effects were observed in response to TGF-β3 and BMP-4, enthesis-associated growth factors known to play a role in entheseal development and maintenance. Conditioned media generated by hMSCs seeded in tendon- and bone-mimetic collagen scaffolds influenced patterns of gene expression regarding enthesis-relevant growth factors, matrix markers, and tendon-to-bone transcription factors for hMSCs within the material. Together, these findings demonstrate that a Gel-SH hydrogel provides a permissive environment for enthesis tissue engineering and highlights the significance of cellular crosstalk between adjacent compartments within a spatially graded biomaterial.

MeSH terms

  • Aggrecans / metabolism
  • Basic Helix-Loop-Helix Transcription Factors
  • Cell Differentiation* / drug effects
  • Chondrogenesis / drug effects
  • Core Binding Factor Alpha 1 Subunit / metabolism
  • Fibrocartilage* / chemistry
  • Fibrocartilage* / drug effects
  • Fibrocartilage* / metabolism
  • Gelatin* / chemistry
  • Humans
  • Hydrogels* / chemistry
  • Hydrogels* / pharmacology
  • Mesenchymal Stem Cells* / cytology
  • Mesenchymal Stem Cells* / drug effects
  • Mesenchymal Stem Cells* / metabolism
  • Paracrine Communication* / drug effects
  • Rotator Cuff
  • Rotator Cuff Injuries / therapy
  • SOX9 Transcription Factor / metabolism
  • Tissue Scaffolds / chemistry

Substances

  • Gelatin
  • Hydrogels
  • Core Binding Factor Alpha 1 Subunit
  • SOX9 Transcription Factor
  • SCX protein, human
  • RUNX2 protein, human
  • SOX9 protein, human
  • Aggrecans
  • ACAN protein, human
  • Basic Helix-Loop-Helix Transcription Factors