Engineering a Biomimetic In Vitro Model of Bruch's Membrane Using Hagfish Slime Intermediate Filament Proteins

Area of Science:

• Biomaterials Science
• Ocular Biology
• Regenerative Medicine

Background:

• Bruch's membrane is crucial for retinal health, regulating nutrient and waste transport between the retinal pigment epithelium (RPE) and vascular layers.
• Aging causes detrimental changes in Bruch's membrane, including thickening and reduced permeability, contributing to age-related macular degeneration (AMD).
• Existing in vitro models often fail to replicate the essential physical and biological properties of native Bruch's membrane.

Purpose of the Study:

• To evaluate recombinant hagfish intermediate filament (rHIF) protein membranes as a biomaterial for an accurate in vitro model of Bruch's membrane.
• To assess if rHIF membranes can replicate the mechanical properties and permeability of both healthy and aged Bruch's membrane.
• To determine the suitability of rHIF membranes for supporting retinal pigment epithelial (RPE) cell culture.

Main Methods:

• Fabrication of membranes from recombinant hagfish intermediate filament (rHIF) proteins.
• Characterization of membrane physical properties: mechanical testing, permeability assays, brightfield microscopy, and scanning electron microscopy.
• Assessment of RPE cell culture compatibility using microscopy and immunocytochemical staining.

Main Results:

• rHIF membranes exhibited suitable semipermeability, nonporosity, and mechanical properties comparable to in vivo Bruch's membrane.
• The rHIF membranes successfully supported the growth and culture of retinal pigment epithelial (RPE) cells.
• The study confirmed that rHIF membranes can accurately mimic both healthy and aged Bruch's membrane characteristics.

Conclusions:

• Recombinant hagfish intermediate filament (rHIF) protein membranes represent a promising biomaterial for developing accurate in vitro models of Bruch's membrane.
• These rHIF membranes provide a valuable tool for investigating the aging process of the subretinal tissue and its role in AMD pathogenesis.
• The developed model facilitates further research into therapeutic strategies for retinal diseases associated with Bruch's membrane dysfunction.