The Diurnal Variation in Mitochondrial Gene in Human Type 2 Diabetic Mesenchymal Stem Cell Grafts

The application of regenerative therapy through stem cell transplantation has emerged as a promising avenue for the treatment of diabetes mellitus (DM). Transplanted tissue homeostasis is affected by disturbances in the clock genes of stem cells. The aim of this study is to investigate the diurnal variation in mitochondrial genes and function after transplantation of adipose-derived mesenchymal stem cells (T2DM-ADSCs) from type 2 diabetic patients into immunodeficient mice. Diurnal variation in mitochondrial genes was assessed by next-generation sequencing. As a result, the diurnal variation in mitochondrial genes showing troughs at ZT10 and ZT22 was observed in the group transplanted with adipose-derived mesenchymal stem cells derived from healthy individuals (N-ADSC). On the other hand, in the group transplanted with T2DM-ADSCs, diurnal variation indicative of troughs was observed at ZT18, with a large phase and amplitude deviation between the two groups. To evaluate the diurnal variation in mitochondrial function, we quantified mitochondrial DNA copy number using the Human mtDNA Monitoring Primer Set, measured mitochondrial membrane potential using JC-1, and evaluated mitophagy staining. The results showed a diurnal variation in mitochondrial DNA copy number, mitophagy, mitochondrial membrane potential, and NF-kB signaling in the N-ADSC transplant group. In contrast, no diurnal variation was observed in T2DM-ADSC transplants. The diurnal variation in mitochondrial function revealed in this study may be a new marker for the efficiency of T2DM-ADSC transplantation.