Self-assembled biomimetic microenvironments with sulfated levan promote kidney epithelial cell growth and reduce inflammatory cytokine release

Abstract

Kidney diseases are a major global health burden, underscoring the need for new strategies to support renal repair. Biomimetic materials that recapitulate extracellular matrix functions can provide structural support while presenting biochemical cues that guide epithelial behavior. Here, we engineered self-assembled collagen type I microenvironments incorporating levan, sulfated levan (sLevan), pea starch (PEA), and sulfated PEA (sPEA) as a sustainable, non-animal-derived class of glycosaminoglycan (GAG) mimetics. Chemical sulfation of levan and starch introduced negative charge, enhanced solubility, and generated derivatives with moderate anti-factor Xa activity compared with heparin. Biochemical assays demonstrated that all polysaccharides were stably incorporated into collagen networks without hindering enzymatic degradability, while sulfation and polymer type modulated fibril assembly kinetics and coating morphology. In solution and when presented within collagen coatings, sPEA starch consistently reduced human kidney epithelial cell (HK-2) metabolic activity and cell numbers, indicating antiproliferative effects. In contrast, sLevan-containing microenvironments supported HK-2 proliferation under basal and hyperglycemic conditions comparable to heparin-containing controls. Notably, sLevan-functionalized coatings significantly suppressed secretion of the proinflammatory cytokine interleukin (IL)-6 and prevented glucose-induced increases in latent transforming growth factor (TGF)-β1, two mediators implicated in tubular inflammation and fibrotic remodeling. Together, these findings indicate that sulfation critically governs the bioactivity of levan- and starch-based GAG mimetics. Collagen/sLevan microenvironments combine tunable matrix assembly, moderate anticoagulant activity, and favorable epithelial growth and cytokine profiles under hyperglycemic stress, highlighting their potential as renewable GAG-mimetic platforms for renal tissue engineering and in-vitro disease modeling.