Direct mitochondrial transfer through MitoCeption. Mitochondria (MT) of
900,000 mesenchymal stromal cells (MSCs) were isolated and transferred
into chondrocytes (CH) via MitoCeption. CH controls were subjected to
the same centrifugation steps without the addition of MT.
(A) MSC-derived MT, stained with MitoTracker (in red),
localized intracellularly in CH monolayers. Scale bar = 100 µm.
(B) Dose-dependent effect of MitoCeption using
increasing concentrations of MT transferred into monolayers of 100,000
CH. Symbols depict averages of 2 measurements ± standard deviation, and
the gray line shows linear regression. (C) Metabolic
activity of CH monolayers as indicated by the conversion of resazurin to
resorufin (ex: 560 nm, em: 590 nm) at 24 and 42 hours after MitoCeption
with MT and senescent MT (sMT), both derived from 900,000 MSCs.
N = 3 donor combinations. (D) mRNA
expression of aggrecan (ACAN), type II collagen (COL2A1; both markers
for chondrogenesis), and B-cell lymphoma 2 (BCL2; marker for cell
survival) in CH monolayers at 2, 6, 26, and 46 hours after MitoCeption
with MT and sMT derived from 900,000 MSCs. ACAN expression was increased
in CH + MT compared with CH right after MitoCeption (T = 2 hours), and
BCL2 was increased in CH + MT 26 hours after MitoCeption (T = 26 hours).
N = 3 donor combinations, 2 technical replicates
per donor. *P < 0.05. Error bars show standard
deviations.