Mechanisms Of Integrin Targeted Peptide Modified Titanium Metal In Periprosthetic Osteolysis

Objective:Periprosthetic-osteolysis(PPO)and the subsequent aseptic loosening of prosthesis are key causes of failed arthroplasty.The activation of osteoclasts induced by wear particles is the key factor contributing to PPO.Therefore,we designed a mussel-derived titanium(Ti)-affinity peptide,(DOPA)4-S5-GRGDS,for the purpose of inhibiting osteoclast activation to prevent PPO and prolong the life of prostheses.Methods:(DOPA)4-S5-GRGDS peptide composed of an integrin-targeting GRGDS peptide and a titanium(Ti)-affinity tetrapeptide(DOPA)4 with catechol groups for surface biofunctionalization of Ti-based prosthesis implants.Mussel bioactive peptides were prepared by standard Fmoc solid-phase peptide synthesis strategy.In order to grafted the DOPA units into the sequence,acetone was used to protect hydroxyl-OH and acetyl-terminated end-peptides were used at N-terminal.We believe that polypeptides can easily adhere to the surface of titanium oxide through the mechanical action of covalent bonds and non-covalent bonds,thus modifying the surface of materials.XPS and AFM were performed to explored ESI-MS of the mussel-derived peptide(DOPA)4-S5-GRGDS after titanium slides uncoated and coated in peptides solutions for 3 hours.Then,the effect of this biomimetic peptide coating on Ti debris-induced osteolysis and osteoclast activation were explored both in vivo and in vitro.In vivo experiments,36 SDs were randomLy divided into three groups:control group,model group and(DOPA)4-S5-GRGDS peptide treatment group.Under strict aseptic conditions,SD rats underwent bilateral distal femoral intramedullary titanium rod implantation.In the model group and(DOPA)4-S5-GRGDS group,100 mL titanium suspension(40%)was injected into the medullary cavity.The control group used the same volume of PBS.Finally,the titanium nail was implanted into the medullary cavity and the surgical wound was sutured.At 6 weeks after operation,excessive chloral hydrate solution was injected intraperitoneally to induce euthanasia.Microscopic CT scanning,H&E and immunohistochemical staining were performed on bilateral femurs of rats.In vitro,we induced and cultured osteoclast differentiation by using Ti metal cell culture plate modified by polypeptide.The effect of DOPA 4-S5-GRGDS peptide on osteoclast activation was observed by TRAP staining,Rt-pcr,immunofluorescence staining and Western blot.Results:Integrin-targeting peptide from mussel can easily adhere to the surface of titanium dioxide through the synergistic action of covalent and non-covalent bonds,thus modifying the surface of titanium-based materials.In vivo,we found that(DOPA)4-S5-GRGDS can effectively reduce osteolysis induced by wear particles around the simulated prosthesis,prevent bone loss and destruction,and effectively inhibit the formation of osteoclasts.In further research,we determined that the integrin targeting peptide coating could inhibit the integrity of extracellular matrix of osteoclasts by specifically binding to integrin alpha v beta 3 subunit,thus affecting the related functions of osteoclasts.Moreover,integrin-targeting peptide can effectively regulate PI3K/Akt and NF-kappa B signaling pathways,thus inhibiting the formation and activation of osteoclasts.Conclusions:In summary,this work demonstrated the effectiveness of a mussel-derived integrin-targeting peptide coatings for the prevention of wear debris-induced PPO on the Ti-based prosthesis implants.Our study indicated that the mussel-derived integrin-targeting peptide can improve bone mass around the prosthesis and alleviate osteolysis caused by wear debris in vivo.In vitro study further revealed that the biomimetic peptide can inhibit osteoclast activation and interfere with function of osteoclast.The mechanism of action was found to be through suppressing osteoclast formation and activation by blocking integrin-αvβ3/PI3K/Akt/NF-κB signaling pathway.Considering the simplicity of surface engineering strategy,the highly biomimetic nature of the peptide coating,and the efficient PPO inhibition demonstrated above,our work would provide a facile and effective means for improving the clinical outcome of Ti-based prosthesis implants.