Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India.
Department of Biomedical Engineering, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India.
Biomacromolecules. 2024 Apr 8;25(4):2286-2301. doi: 10.1021/acs.biomac.3c01148. Epub 2024 Mar 19.
Bone defects show a slow rate of osteoconduction and imperfect reconstruction, and the current treatment strategies to treat bone defects suffer from limitations like immunogenicity, lack of cell adhesion, and the absence of osteogenic activity. In this context, bioactive supramolecular peptides and peptide gels offer unique opportunities to develop biomaterials that can play a dominant role in the biomineralization of bone tissues and promote bone formation. In this article, we have demonstrated the potential of six tetrapeptides for specific binding to hydroxyapatite (HAp), a major inorganic component of the bone, and their effect on the growth and osteogenic differentiation of mesenchymal stem cells (MSCs). We adopted a simplistic approach of rationally designing amphiphilic peptides by incorporating amino acids, Ser, pSer, Pro, Hyp, Asp, and Glu, which are present in either collagenous or noncollagenous proteins and render properties like antioxidant, calcification, and mineralization. A total of six tetrapeptides, Trp-Trp-His-Ser (WWHS), Trp-Trp-His-pSer (WWHJ), Trp-Trp-His-Pro (WWHP), Trp-Trp-His-Hyp (WWHO), Trp-Trp-His-Asp (WWHD), and Trp-Trp-His-Glu (WWHE), were synthesized. Four peptides were found to self-assemble into nanofibrillar gels resembling the extracellular matrix (ECM), and the remaining two peptides (WWHJ, WWHP) self-assembled into nanorods. The peptides showed excellent cell adhesion, encapsulation, proliferation, and migration and induced the differentiation of mesenchymal stem cells (MSCs), as evident from the enhanced mineralization, resulting from the upregulation of osteogenic markers, RUNX 2, COL I, OPN, and OCN, alkaline phosphatase (ALP) production, and calcium deposition. The peptides also induced the downregulation of inflammatory markers, TNF-α and iNOS, and the upregulation of the anti-inflammatory marker, IL-10, resulting in M2 macrophage polarization. RANKL and TRAP genes were downregulated in a coculture system of MC3T3-E1 and RAW 264.7 cells, implying that peptides promote osteogenesis and inhibit osteoclastogenesis. The peptide-based biomaterials developed in this work can enhance bone regeneration capacity and show strong potential as scaffolds for bone tissue engineering.
骨缺损表现出缓慢的成骨作用和不完善的重建，当前治疗骨缺损的策略受到免疫原性、缺乏细胞黏附性和缺乏成骨活性等限制。在这种情况下，生物活性超分子肽和肽凝胶为开发能够在骨组织生物矿化中发挥主导作用并促进骨形成的生物材料提供了独特的机会。在本文中，我们展示了六种四肽与羟基磷灰石（HAp）特异性结合的潜力，HAp 是骨的主要无机成分，以及它们对间充质干细胞（MSCs）生长和成骨分化的影响。我们通过合理设计具有两亲性的肽来采用一种简单的方法，这些肽包含存在于胶原蛋白或非胶原蛋白中的氨基酸，如丝氨酸、磷酸丝氨酸、脯氨酸、羟脯氨酸、天冬氨酸和谷氨酸，这些氨基酸赋予了抗氧化、钙化和矿化等特性。总共合成了六种四肽，色氨酸-色氨酸-组氨酸-丝氨酸（WWHS）、色氨酸-色氨酸-组氨酸-磷酸丝氨酸（WWHJ）、色氨酸-色氨酸-组氨酸-脯氨酸（WWHP）、色氨酸-色氨酸-组氨酸-羟脯氨酸（WWHO）、色氨酸-色氨酸-组氨酸-天冬氨酸（WWHD）和色氨酸-色氨酸-组氨酸-谷氨酸（WWHE）。发现其中四种肽自组装成类似于细胞外基质（ECM）的纳米纤维凝胶，而另外两种肽（WWHJ、WWHP）自组装成纳米棒。这些肽表现出出色的细胞黏附性、封装性、增殖性和迁移性，并诱导间充质干细胞（MSCs）分化，这表现在矿化增强，成骨标志物 RUNX2、COL1、OPN 和 OCN 的上调，碱性磷酸酶（ALP）的产生和钙沉积。这些肽还诱导炎症标志物 TNF-α 和 iNOS 的下调和抗炎标志物 IL-10 的上调，导致 M2 巨噬细胞极化。在 MC3T3-E1 和 RAW264.7 细胞的共培养系统中，RANKL 和 TRAP 基因下调，这表明肽促进成骨作用并抑制破骨细胞形成。本工作中开发的基于肽的生物材料可以增强骨再生能力，并显示出作为骨组织工程支架的强大潜力。
