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Wheemoon Cho,E Ske Kim,강창모,지영훈,김종일,박상준,손영숙,김춘호 한국조직공학과 재생의학회 2017 조직공학과 재생의학 Vol.14 No.4
Mesenchymal stem cells (MSCs), which are multipotent and have self-renewal ability, support the regeneration of damaged normal tissue. A number of external stimuli promote migration of MSCs into peripheral blood and support their participation inwound healing. In an attempt to harness the potential beneficial effects of such external stimuli, we exposed human MSCs (hMSCs) to one such stimulus—low-dose ionizing radiation (LDIR)—and examined their biological properties. To this end, we evaluated differences in proliferation, cell cycle, DNA damage, expression of surface markers (CD29, CD34, CD90, and CD105), and differentiationpotential ofhMSCs before and after irradiationwith c-rays generated using a 137CSirradiator.At doses less than 50 mGy, LDIR had no significant effect on the viability or apoptosis of hMSCs. Interestingly, 10 mGyofLDIR increased hMSC viability by 8% (p\0.001) comparedwith non-irradiatedhMSCs.At doses less than 50 mGy, LDIR did not induceDNA damage, including DNA strand breaks, or cause cellular senescence or cell-cycle arrest. Surface marker expression and in vitro differentiation potential of hMSCs were maintained after two exposures to LDIR at 10 mGy per dose. In conclusion, a two-dose exposure to LDIR at 10 mGy per dose not only facilitates proliferation of hMSCs, it alsomaintains the stem cell characteristics of hMSCswithout affecting their viability.These results provide evidence for the potential ofLDIRas an external stimulus for in vitro expansion of hMSCs and application in tissue engineering and regenerative medicine.
키토산 기반 siRNA 나노전달체 제조 및 유전자 억제 효율
이은선(Eunsun Lee),조휘문(Wheemoon Cho),이재호(Jae Ho Lee),박상준(Sang Jun Park),김용희(Yong-Hee Kim),김천호(Chun-Ho Kim) 한국고분자학회 2021 폴리머 Vol.45 No.5
세포질로의 siRNA 전달을 위해, 본 연구는 양이온성의 키토산과 음이온성인 tripolyphosphate(TPP)의 이온결합을 이용하여 유전자 나노전달체(Chi-TPP-siRNA)를 제조하였다. 키토산의 분자량 및 키토산과 TPP의 몰비에 따른 나노입자(Chi-TPP)의 물리화학적 특성을 동적광산란기(DLS)와 전자 현미경(EM)으로 확인하였다. siRNA 담지 효과는 전기영동으로 확인하였다. MDA-MB-231에 대한 나노전달체의 생물학적 특성을 공초점현미경으로 확인하였다. 모델 siRNA 담지 Chi-TPP-siRNA 나노전달체는 직경과 다분산도가 각각 223.5 nm, 0.229인 구형으로 형성되었다. 나노전달체 처리군(500 μg/mL)에서의 세포 생존율은 88% 이상이었다. siGFP를 담지한 나노전달체(Chi-TPP-siGFP)는 48.1%의 green fluorescent protein(GFP) 유전자 억제 효율을 보였다. 결과적으로 생체친화성의 Chi-TPP-siRNA 나노전달체는 다양한 유전자 치료에 이용될 수 있다. This study is to prepare chitosan-based siRNA nano-carriers (Chi-TPP-siRNA) using ionic gelation between cationic chitosan and anionic tripolyphosphate (TPP) for delivery of siRNA to cytoplasm. We studied the effect of the molecular weight of chitosan and the mole ratio of chitosan/TPP on the physicochemical properties of Chi-TPP nanoparticles by using dynamic light scattering and electron microscopy. The siRNA encapsulation was evaluated by using electrophoresis. The biological properties of Chi-TPP-siRNA on MDA-MB-231 cells were evaluated by using confocal laser microscopy. The resulting Chi-TPP-siRNAs, using control siRNA, were formed in sphere shape. The diameter and the PdI value of Chi-TPP-siRNA were 223.5 nm and 0.229, respectively. The cell viability of Chi-TPP-siRNA at the concentration of 500 μg/mL was above 88%. Green fluorescent protein (GFP) silencing effect of Chi-TPP-siGFP was evaluated to be 48.1%. In conclusion, the biocompatible nano-carrier, Chi-TPP-siRNA, could be used in various gene therapy.
Kim, Min Sup,Park, Sang Jun,Cho, Wheemoon,Gu, Bon Kang,Kim, Chun-Ho MDPI 2016 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.17 No.1
<P>The goal to successful wound healing is essentially to immobilize and recruit appropriate numbers of host stem or progenitor cells to the wound area. In this study, we developed a chitosan nanofiber-immobilized neuropeptide substance-P (SP), which mediates stem cell mobilization and migration, onto the surfaces of nanofibers using a peptide-coupling agent, and evaluated its biological effects on stem cells. The amount of immobilized SP on chitosan nanofibers was modulated over the range of 5.89 ± 3.27 to 75.29 ± 24.31 ng when reacted with 10 to 500 ng SP. <I>In vitro</I> migration assays showed that SP-incorporated nanofibers induced more rapid migration of human mesenchymal stem cells on nanofibers compared to pristine samples. Finally, the conjugated SP evoked a minimal foreign body reaction and recruited a larger number of CD29- and CD44-positive stem cells into nanofibers in a mouse subcutaneous pocket model.</P>