Endothelial cells

Biolaminin isoforms for vascular endothelial cell culture

Endothelial cells that make up the vascular network in all organs of the body express and secrete laminin-411 and laminin-511 (Hallman et al., 2005). During angiogenesis, laminins are produced and deposited from the stalk cells to the tip cell filopodia (Jakobsson, 2008).

Primary endothelial cells, such as human umbilical cord endothelial cells (HUVECs), grow long-term on Biolaminin 521, -511, or -411 with continuous strong expression of the von Willenbrandt factor (vWF). Previously, mature endothelial cells were often grown on fibronectin which resulted in de-differentiation of the cells within hours to days that could be seen by a complete loss of specific endothelial markers (such as the vWF).

Endothelial progenitor cells were efficiently differentiated from human embryonic stem cells on Biolaminin 521 (Nguyen et al. 2016).

In addition to alpha5 laminins (laminin-511 and -521), alpha4 laminins (laminin-411 and -421) are present in endothelial basement membranes. Wagner et al. 2018 reported an endothelial switch from laminin 421 to 411 during aging and different endothelial cell properties on the isoforms.

Biolaminin 411 (laminin-411) alone was shown to induce endothelial differentiation of induced pluripotent stem cells with specific identified pathways responsible for this effect. The differentiation was clearly improved compared to collagen I or Matrigel, as well as over laminin-111 or -511 (Hall et al. 2022).

Isolation and expansion of corneal endothelial progenitors

Corneal endothelial cells (CECs) are highly polarized flat cells that form a uniform monolayer of the innermost layer of the cornea, separating the cornea from the aqueous humor that fills the anterior chamber. CECs play several essential roles in corneal homeostasis and are specialized in regulating corneal hydration and transparency.

The basal surface of the CSCs rest on an amorphous collagenous membrane, Descemet’s membrane, composed of type IV collagen, type VIII collagen, perlecan, nidogens, laminin-332, laminin-411, and laminin-511 (Kabosova et al., 2007). Integrin α3β1 is the only protein found exclusively at the basal surface of the CSCs, forming an almost homogenous layer (He et al., 2016). Ligands of the integrin α3β1, such as laminin-511 and laminin-521, are efficient coating substances that improve the yield of in vitro CEC cultures.

Corneal endothelial progenitors are efficiently isolated and expanded on Biolaminin 511 (Hara et al., 2014). Hara and colleagues demonstrate that the proliferative capacity of the endothelial progenitors is very high on laminin-511 compared to conventional methods. Biolaminin 511 can be used to rapidly isolate and expand a homogenous population of endothelial progenitors that can be differentiated into endothelial cells in a serum-free environment.