Immune-instructive copolymer scaffolds using plant-derived nanoparticles to promote bone regeneration

Abstract

Background Age-driven immune signals cause a state of chronic low-grade inflammation and in consequence affect bone healing and cause challenges for clinicians when repairing critical-sized bone defects in elderly patients. Methods Poly(l-lactide-co-ɛ-caprolactone) (PLCA) scaffolds are functionalized with plant-derived nanoparticles from potato, rhamnogalacturonan-I (RG-I), to investigate their ability to modulate inflammation in vitro in neutrophils and macrophages at gene and protein levels. The scaffolds’ early and late host response at gene, protein and histological levels is tested in vivo in a subcutaneous rat model and their potential to promote bone regeneration in an aged rodent was tested in a critical-sized calvaria bone defect. Significant differences were tested using one-way ANOVA, followed by a multiple-comparison Tukey’s test with a p value ≤ 0.05 considered significant. Results Gene expressions revealed PLCA scaffold functionalized with plant-derived RG-I with a relatively higher amount of galactose than arabinose (potato dearabinated (PA)) to reduce the inflammatory state stimulated by bacterial LPS in neutrophils and macrophages in vitro. LPS-stimulated neutrophils show a significantly decreased intracellular accumulation of galectin-3 in the presence of PA functionalization compared to Control (unmodified PLCA scaffolds). The in vivo gene and protein expressions revealed comparable results to in vitro. The host response is modulated towards anti-inflammatory/ healing at early and late time points at gene and protein levels. A reduced foreign body reaction and fibrous capsule formation is observed when PLCA scaffolds functionalized with PA were implanted in vivo subcutaneously. PLCA scaffolds functionalized with PA modulated the cytokine and chemokine expressions in vivo during early and late inflammatory phases. PLCA scaffolds functionalized with PA implanted in calvaria defects of aged rats downregulating pro-inflammatory gene markers while promoting osteogenic markers after 2 weeks in vivo. Conclusion We have shown that PLCA scaffolds functionalized with plant-derived RG-I with a relatively higher amount of galactose play a role in the modulation of inflammatory responses both in vitro and in vivo subcutaneously and promote the initiation of bone formation in a critical-sized bone defect of an aged rodent. Our study addresses the increasing demand in bone tissue engineering for immunomodulatory 3D scaffolds that promote osteogenesis and modulate immune responses.

Decellularized Placental Sponge: A Platform for Coculture of Mesenchymal Stem Cells/Macrophages to Assess an M2 Phenotype and Osteogenic Differentiation In Vitro and In Vivo

“…Consequently, the decreased level of NO production in macrophages/AD-MSCs cocultured on the DPS appears to be linked to a reduction in TNF-α production. It is worth noting that macrophages, in addition to cytokine and NO measurements, have a general function in phagocytosis, which is not restricted to a specific phenotype . It can be considered an influential factor besides cytokine and NO measurement in investigating M1 and M2 phenotypes.…”

“…It is worth noting that macrophages, in addition to cytokine and NO measurements, have a general function in phagocytosis, which is not restricted to a specific phenotype. 100 It can be considered an influential factor besides cytokine and NO measurement in investigating M1 and M2 phenotypes. Several studies have shown that anti-inflammatory macrophages tend to produce higher levels of IL-10 and exhibit an increased capacity for phagocytosing apoptotic thymocytes.…”

Phytochemical Compounds Involved in the Bone Regeneration Process and Their Innovative Administration: A Systematic Review

“…Plant-derived nanoparticles from potato containing rhamnogalacturonan-I (with relatively higher amount of gallactose) have been used for poly (L-lactide-co-ɛ-caprolactone) scaffolds functionalization revealing a downregulation of pro-inflammatory gene markers and promotion of osteogenic markers [ 79 ]. The same plant-derived pectin, rhamnogalacturonan-I, has been employed for the nanocoating of im-plants influencing osteoblast proliferation, mineralization and gene expression (Runt-related transcription factor 2 (Runx2), alkaline phosphate (ALP), osteocalcin (Bglap), α-1 type I collagen (Col1a1), receptor activator of NF-κB ligand (RANKL)) [ 80 ].…”

Phytochemical Compounds Involved in the Bone Regeneration Process and Their Innovative Administration: A Systematic Review

“…Psidium guajava [103] malvidin, cyanidin and delphinidin inhibition of MSC adipogenesis and downregulation of FABP4 and adiponectin genes. Solanum tuberosum [77,78] Crocin, Crocetin ↑ ALP activity and ALP mRNA expression in MSCs Crocus sativus L. [108] Sinapic acid activation of TGF-β1/BMP/Smads/Runx2 signaling pathways => osteoblast differentiation…”

“…Plant-derived nanoparticles from potato containing rhamnogalacturonan-I (with relatively higher amount of gallactose) were used for poly(L-lactide-co-ɛ-caprolactone) scaffolds functionalization revealing a downregulation of pro-inflammatory gene markers and promotion of osteogenic markers [77]. The same plant-derived pectin, rhamnogalacturonan-I, was employed for nanocoating of im-plants influencing osteoblast proliferation, mineralization, and gene expression (Runt-related transcription factor 2 (Runx2), alkaline phosphate (ALP), osteocalcin (Bglap), α-1 type I collagen (Col1a1), receptor activator of NF-κB ligand (RANKL)) [78].…”