Recombinant spider silk membranes promote human renal epithelial differentiation and function

Area of Science:

• Biomaterials Science
• Cell Biology
• Tissue Engineering

Background:

• Conventional porous membranes (e.g., transwells) used for cell culture lack the structural and biochemical cues of native basement membranes.
• This deficiency can impede cellular differentiation and function, limiting the physiological relevance of in vitro models.
• Renal epithelial cells are particularly challenging to differentiate in culture using standard methods.

Purpose of the Study:

• To develop and evaluate a novel nanofibrillar biomaterial (FN-silk) that mimics the basement membrane microenvironment.
• To assess the FN-silk membrane's efficacy as a culture substrate for renal epithelial cells (RPTEC/TERT1).
• To compare the differentiation, function, and potential toxicity of cells cultured on FN-silk versus conventional membranes.

Main Methods:

• Fabrication of FN-silk membranes using recombinant spider silk functionalized with RGD and coated with laminin-521.
• Culturing renal epithelial cells (RPTEC/TERT1) on both FN-silk and conventional membranes.
• Assessment of cell morphology, mRNA expression (RNA-sequencing), barrier properties, and transporter activity using microscopy, sequencing, and transport assays.

Main Results:

• Both membrane types supported basic barrier integrity and tight junction expression.
• RPTEC/TERT1 cells on FN-silk exhibited differentiated morphology and reduced cell death markers.
• FN-silk cultures demonstrated directional anion and cation transport, unlike conventional membranes.
• Conventional membranes released bisphenols, potentially causing endocrine disruption.

Conclusions:

• FN-silk membranes, functionalized with kidney-specific laminin-521, reduce cellular stress and maintain renal epithelial cell differentiation and function.
• These biomimetic membranes represent a next-generation material for creating physiologically relevant in vitro models of renal epithelia.
• The findings highlight the importance of biomaterial design in achieving functional cell differentiation for research and drug testing.