Fibrinogen supports self-renewal of mesenchymal stem cells under serum-reduced condition through autophagy activation

Mesenchymal stem cells (MSCs) are somatic stem cells used in cell transplantation therapy for tissue injuries and inflammatory diseases because of their ability to support tissue regeneration and to suppress inflammation. While their applications are expanding, needs for automation of culture procedures with reduction of animal-derived materials to meet stable quality and suppliability are also increasing. On the other hand, the development of molecules that safely support cell adherence and expansion on a variety of interfaces under the serum-reduced culture condition remains a challenge. We report here that fibrinogen enables MSC culture on various materials with low cell adhesion property even under serum-reduced culture conditions. Fibrinogen promoted MSC adhesion and proliferation by stabilizing basic fibroblast growth factor (bFGF), which was secreted in the culture medium by autocrine, and also activated autophagy to suppress cellar senescence. Fibrinogen coating allowed MSCs expansion even on the polyether sulfone membrane that represents very low cell adhesion, and the MSCs showed therapeutic effects in a pulmonary fibrosis model. This study demonstrates that fibrinogen is currently the safest and most widely available extracellular matrix and can be used as a versatile scaffold for cell culture in regenerative medicine.