盧星華1,2 李新城3 林登龍1,2 陳光國1,2 張心湜1,2
Cellular autophagy of human stem cells in the process of differentiation
Shing-Hwa Lu1, Hsin-Chen Lee3, Alex T.L. Lin, Kuang-Kuo Chen, and Luke S. Chang
1,2Department of Urology, Taipei-Veterans General Hospital and School of Medicine, National Yang-Ming University; 3Department of Pharmacology, School of Medicine, National Yang-Ming University
Purpose: The study is conducted to understand the cellular autophagy of human adipose derived stem cells during the process of smooth muscle cell (SMC) differentiation.
Materials and Methods: Human adipose derived stem cell (hADSC) were induced differentiation into SMC by the use of low-serum level smooth muscle induction medium (SMIM) during SMC differentiation. Real-time PCR analysis were used to check the mRNA expression of smooth muscle marker genes such as α-smooth muscle actin (SMA), SM22α, Calponin, Caldesmon and smooth muscle myosin heavy chain (MHC). We used western blot assay and immumofluorescence staining were also usedImmunofluorescence staining of the cellular actin cytoskeleton to testify the change at protein level.
Results: There was increased expression of smooth muscle marker genes such as SMA and smooth muscle MHC from hADSCs which were exposed to SMIM for 6 weeks. Increased cellular complexity and granularity in induced hADSC, suggesting the intracellular organelles might be increased during the process of SMC differentiation. The lysosome content is significantly increased but mitochondria and endoplasmic reticulum are not. The increased protein content of the lysosomal-associated membrane protein 1 (LAMP-1) confirmed the increase in lysosome content during SMC differentiation. On the other hand, conversion from LC3-I to LC3-II was increased during SMC differentiation and significant increase was observed at the 3w-differentiation.
Conclusion: These results suggest that autophagy appears to be up-regulated in the early stage of SMC differentiation. Autophagy might play an important role in SMC differentiation of ADSC which may be potential biomaterial for the treatment of urinary incontinence and for bladder reconstitution.