HOW TO CULTURE RENAL CELLS ON LAMININ SUBSTRATES

Laminins play an important role in kidney development

Both the tubular and glomerular epithelial cells of the kidney develop from mesenchymal stem cells during embryogenesis. Unique conversion of nonpolar cells to polarized epithelial cells thus occurs in the embryonic kidney. Organ cultures of mesenchymal cells from the mouse embryonic kidney have shown that laminins are particularly important for epithelial cell development (Ekblom, 1991).

Laminin 521 is the major laminin expressed in the mature glomerular basement membrane (GBM). During glomerulogenesis there are developmental transitions in laminin trimer deposition (St John and Abrahamson, 2001). Initially, the GBM contains laminin 111, 411 and 511. By the capillary loop stage during GMB maturation, laminin 111 is eliminated from the GBM and the beta 2 chain begins to accumulate while the beta 1 chain is down-regulated. At maturity, only laminin 521 is detected in the GBM.

A simple, reproducible and defined glomerular basement membrane filtration model on Biolaminin 521

Primary glomerular endothelial cells (GEnCs) is an important tool for studying glomerulosclerotic mechanisms and in drug development. In a publication by researchers at Novo Nordisk A/S, the authors establish a simple, reproducible and defined in vitro model of quiescent hGEnC monolayer on recombinant human Biolaminin 521 LN (Pajęcka, 2017). Biolaminin 521 best supported hGEnC attachment and spreading and culture on laminin resulted in a physiologically relevant barrier to 70 kDa dextrans which was 82 % tighter than that formed on collagen type IV. Furthermore, only hGEnCs cultured on laminin showed plasma-membrane localized zonula occludens-1 and vascular endothelial cadherin indicative of proper tight and adherens junctions. Biolaminin 521 culture promotes all the characteristics of the quiescent hGEnC monolayer: cobblestone morphology, well-defined adherens junctions, and physiological perm-selectivity.

Laminin alpha-5 expressed in the mature glomerular basement membrane support culture of podocytes

The a-5 chain laminins (laminin 521 and laminin 511) binds predominantly to the integrin α3β1 receptor on the basal surface of podocytes. The binding of laminin 521 and/or laminin 511 to this integrin is essential for the formation of the typical glomerular capillary loop structure. Lack of binding to the α3β1 receptor results in severe kidney glomerular defects during development (Kikkawa, 2003). In a Nature protocols publication, researchers from professor Inger's group at Harvard University have developed a detailed protocol for the directed differentiation of human iPS cells into mature, post-mitotic kidney glomerular podocytes with high (>90%) efficiency within 26 d and under chemically defined conditions, without genetic manipulations or subpopulation selection (Musah 2018). Biolaminin 511 LN (LN511) was used as a cell culture substrate. The authors also describe how these iPS cell-derived podocytes may be induced to form within a microfluidic organ-on-a-chip culture device to build a human kidney Glomerulus Chip that mimics the structure and function of the kidney glomerular capillary wall in vitro. 

Mesangial cells produce laminin 421

Mesangial cells produce laminin 421 and organize glomerular capillaries by binding the laminin α-5 via α3β1 integrin and Lutheran receptor (Kikkawa, 2003). Thus, mesangial cells are important for the development and reparation of microvasculature and glomerulogenesis in general (Abrass, 2010). For the culture of mesangial cells, we recommend Biolaminin 421.