Biofunctionalized gelatin hydrogels support development and maturation of iPSC-derived cortical organoids.

Human neural organoid models have become an important tool for studying neurobiology. However, improving the representativeness of neural cell populations in such organoids remains a major effort. In this work, we compared Matrigel, a commercially available matrix, to a neural cadherin (N-cadherin) peptide-functionalized gelatin methacryloyl hydrogel (termed GelMA-Cad) for culturing cortical neural organoids. We determined that peptide presentation can tune cell fate and diversity in gelatin-based matrices during differentiation. Of particular note, cortical organoids cultured in GelMA-Cad hydrogels mapped more closely to human fetal populations and produced neurons with more spontaneous excitatory postsynaptic currents relative to Matrigel. These results provide compelling evidence that matrix-tethered signaling peptides can influence neural organoid differentiation, opening an avenue to control stem cell fate. Moreover, outcomes from this work showcase the technical utility of GelMA-Cad as a simple and defined hydrogel alternative to Matrigel for neural organoid culture.

Growth factor free, peptide-functionalized gelatin hydrogel promotes arteriogenesis and attenuates tissue damage in a murine model of critical limb ischemia.

Critical limb ischemia (CLI) occurs when blood flow is restricted through the arteries, resulting in ulcers, necrosis, and chronic wounds in the downstream extremities. The development of collateral arterioles (i.e. arteriogenesis), either by remodeling of pre-existing vascular networks or de novo growth of new vessels, can prevent or reverse ischemic damage, but it remains challenging to stimulate collateral arteriole development in a therapeutic context. Here, we show that a gelatin-based hydrogel, devoid of growth factors or encapsulated cells, promotes arteriogenesis and attenuates tissue damage in a murine CLI model. The gelatin hydrogel is functionalized with a peptide derived from the extracellular epitope of Type 1 cadherins. Mechanistically, these "GelCad" hydrogels promote arteriogenesis by recruiting smooth muscle cells to vessel structures in both ex vivo and in vivo assays. In a murine femoral artery ligation model of CLI, delivery of in situ crosslinking GelCad hydrogels was sufficient to restore limb perfusion and maintain tissue health for 14 days, whereas mice treated with gelatin hydrogels had extensive necrosis and autoamputated within 7 days. A small cohort of mice receiving the GelCad hydrogels were aged out to 5 months and exhibited no decline in tissue quality, indicating durability of the collateral arteriole networks. Overall, given the simplicity and off-the-shelf format of the GelCad hydrogel platform, we suggest it could have utility for CLI treatment and potentially other indications that would benefit from arteriole development.

Growth factor-free, peptide-functionalized gelatin hydrogel promotes arteriogenesis and attenuates tissue damage in a murine model of critical limb ischemia.

Critical limb ischemia (CLI) occurs when blood flow is restricted through the arteries, resulting in ulcers, necrosis, and chronic wounds in the downstream extremities. The development of collateral arterioles (i.e. arteriogenesis), either by remodeling of pre-existing vascular networks or de novo growth of new vessels, can prevent or reverse ischemic damage, but it remains challenging to stimulate collateral arteriole development in a therapeutic context. Here, we show that a gelatin-based hydrogel, devoid of growth factors or encapsulated cells, promotes arteriogenesis and attenuates tissue damage in a murine CLI model. The gelatin hydrogel is functionalized with a peptide derived from the extracellular epitope of Type 1 cadherins. Mechanistically, these "GelCad" hydrogels promote arteriogenesis by recruiting smooth muscle cells to vessel structures in both ex vivo and in vivo assays. In a murine femoral artery ligation model of CLI, delivery of in situ crosslinking GelCad hydrogels was sufficient to restore limb perfusion and maintain tissue health for 14 days, whereas mice treated with gelatin hydrogels had extensive necrosis and autoamputated within 7 days. A small cohort of mice receiving the GelCad hydrogels were aged out to 5 months and exhibited no decline in tissue quality, indicating durability of the collateral arteriole networks. Overall, given the simplicity and off-the-shelf format of the GelCad hydrogel platform, we suggest it could have utility for CLI treatment and potentially other indications that would benefit from arteriole development.