Collagen IV assembly is influenced by fluid flow in kidney cell-derived matrices

Area of Science:

• Nephrology
• Cell Biology
• Biomaterials Science

Background:

• Kidney filtration relies on the basement membrane assembled by podocytes and endothelial cells.
• The impact of fluid flow on basement membrane assembly and organization is not well understood.

Purpose of the Study:

• To investigate how laminar fluid flow influences the composition and assembly of kidney cell-derived matrix.
• To understand the role of prolyl 4-hydroxylase (P4HA1) in flow-mediated matrix remodeling.

Main Methods:

• Co-culture of podocytes and glomerular endothelial cells in a high-flow bioreactor.
• Immunofluorescence, matrix image analysis, and proteomic analysis of cell-derived matrix.
• CRISPR-Cas9 gene editing to tag endogenous COL4A2 with a luminescent marker (HiBiT).

Main Results:

• Laminar fluid flow induced remodeling of collagen IV in the kidney basement membrane.
• Proteomic analysis revealed changes in matrix protein abundance and composition under flow, including P4HA1.
• Collagen IV secretion was consistent under static and flow conditions, but P4HA1 knockdown significantly reduced secretion, particularly under flow.

Conclusions:

• Fluid flow significantly affects the composition, modification, and organization of kidney cell-derived matrix.
• This study provides a novel in vitro system for studying flow-induced matrix alterations in kidney development and disease.