Optimizing beta cell function through mesenchymal stromal cell-mediated mitochondria transfer

Area of Science:

• Cell Biology
• Immunology
• Endocrinology

Background:

• Pretransplant islet culture often leads to reduced islet cell mass and impaired insulin secretion.
• Mesenchymal stromal cells (MSCs) can improve islet function in vitro, correlating with better in vivo graft outcomes.
• Insulin secretion is tightly regulated by mitochondrial ATP production in beta-cells.

Purpose of the Study:

• To investigate if improved islet function after coculture with MSCs is due to mitochondrial transfer from MSCs to islets.
• To elucidate the mechanism and extent of mitochondrial transfer between MSCs and islet beta-cells.

Main Methods:

• Coculture of human adipose-derived MSCs with human islet beta-cells.
• Fluorescence imaging to visualize and confirm mitochondrial transfer.
• Comparison of mitochondrial transfer efficiency between human and mouse islets under various conditions (e.g., hypoxia).

Main Results:

• Demonstrated direct mitochondrial transfer from human MSCs to human islet beta-cells in coculture.
• Identified tunneling nanotube (TNT)-like structures as a mechanism for mitochondrial transfer.
• Observed greater mitochondrial transfer to human islets compared to mouse islets, potentially due to greater cellular stress in human islets.
• Showed increased MSC-mediated mitochondrial transfer to hypoxia-exposed mouse islets.

Conclusions:

• Mesenchymal stromal cells effectively transfer mitochondria to islet beta-cells, enhancing their function.
• Mitochondrial transfer, potentially via TNTs, is a key mechanism by which MSCs support islet health.
• Optimizing MSC-derived mitochondrial transfer could enhance the therapeutic potential of MSCs for clinical islet transplantation, especially for compromised beta-cells.