TGF‐β1‐activated type 2 dendritic cells promote wound healing and induce fibroblasts to express tenascin c following corneal full‐thickness hydrogel transplantation

Abstract

We showed previously that 1‐ethyl‐3‐(3‐dimethylamino‐propyl)‐carbodiimide hydrochloride (EDC) cross‐linked recombinant human collagen III hydrogels promoted stable regeneration of the human cornea (continued nerve and stromal cell repopulation) for over 4 years. However, as EDC cross linking kinetics were difficult to control, we additionally tested a sterically bulky carbodiimide. Here, we compared the effects of two carbodiimide cross linkers—bulky, aromatic N‐cyclohexyl‐N0‐(2‐morpholinoethyl)‐carbodiimide (CMC), and nonbulky EDC—in a mouse corneal graft model. Murine corneas undergoing full‐thickness implantation with these gels became opaque due to dense retro‐corneal membranes (RCM). Corneal epithelial cytokeratin 12 and alpha smooth muscle actin indicative of functional tissue regeneration and wound contraction were observed in RCM surrounding both hydrogel types. However, quantitatively different levels of infiltrating CD11c+ dendritic cells (DC) were found, suggesting a hydrogel‐specific innate immune response. More DC infiltrated the stroma surrounding EDC‐N‐hydroxysuccinimide (NHS) hydrogels concurrently with higher fibrosis‐associated tenascin c expression. The opposite was true for CMC‐NHS gels that had previously been shown to be more tolerising to DC. In vitro studies showed that DC cultured with transforming growth factor β1 (TGF‐β1) induced fibroblasts to secrete more tenascin c than those cultured with lipopolysaccharide and this effect was blocked by TGF‐β1 neutralisation. Furthermore, tenascin c staining was found in 40‐ to 50μm long membrane nanotubes formed in fibroblast/DC cocultures. We suggest that TGF‐β1 alternatively activated (tolerising) DC regulate fibroblast‐mediated tenascin c secretion, possibly via local production of TGF‐β1 in early wound contraction, and that this is indirectly modulated by different hydrogel chemistries.

Dual-crosslinked regenerative hydrogel for sutureless long-term repair of corneal defect

“…Its larger pendent groups can effectively slow down the crosslinking reaction and provide sufficient operating window at room temperature [ 45 ]. More importantly, CMC/NHS crosslinking system has been proven not to participate in the final crosslinked products and toxic-free on the living organization [ 45 , 46 , 56 ]. Therefore, we chose CMC/NHS as the chemical crosslinker to form the first pDCSM-G polymer network.…”

“…A recent study showed that a decellularized porcine corneal stroma derived hydrogel enabled fast corneal re-epithelialization after gelation at 37 °C [ 44 ], but such hydrogel alone exhibited low transparency and weak mechanical strength. The introduction of N -cyclohexyl- N’ -(2-morpholinoethyl) carbodiimide metho- p -toluenesulfonate/ N -hydroxysuccinimide (CMC/NHS) crosslinker significantly improved the strength of decellularized porcine cornea derived hydrogel at room temperature but did not significantly affect its bioactivity [ 45 , 46 ]. However, collagenase and metalloproteinase [ 47 ] are secreted abundantly during matrix repair, which may prevent the decellularized cornea hydrogel from long-term retention on corneal defect.…”

Role of Tunneling Nanotubes in Viral Infection, Neurodegenerative Disease, and Cancer

“…It has been suggested that TNTs could be exploited in vivo to deliver immunomodulatory protein which could either inhibit or promote inflammation. In vitro studies provide the evidence for the presence of tenascin-C in TNTs which are indication for their critical role in tissue remodeling ( 46 ).…”

Hydrogels as Emerging Materials for Cornea Wound Healing

“…2018 [158] Collagen hydrogels, 2 different crosslinked collagen hydrogels Mouse Regulate secretion of Tenascin c from fibroblasts. 2019 [159] Collagen Crosslinked with PRA Rabbit Remodeling of corneal epithelium and stroma. 2019 [61] Collagen vitrigel containing biomimetic synthetic Bowman's membrane and Stromal layer.…”