Subcutaneous priming of protein-functionalized chitosan scaffolds improves function following spinal cord injury
MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS
Authors: Ham, Trevor R.; Pukale, Dipak D.; Hamrangsekachaee, Mohammad; Leipzig, Nic D.
Abstract
Strategies using neural stem cells (NSCs) to aid regeneration following spinal cord injury (SCI) show much promise, but challenges remain regarding implementation and efficacy. In this work, we explored the use of an NSC-seeded scaffold consisting of covalently immobilized interferon-gamma and rat NSCs within a hydrogel matrix (methacrylamide chitosan). We placed the scaffolds within the subcutaneous environment of rats, allowing them to incubate for 4 weeks in order to prime them for regeneration prior to being transplanted into a right lateral hemisection SCI model in the same animal. We found that subcutaneous priming reduced the lineage commitment of encapsulated NSCs, as observed by increased nestin expression and decreased NeuN expression. When combined with intracellular sigma peptide administration (which reduces inhibition from the glial scar), subcutaneous maturation improved functional outcomes, which were assessed by BBB score and quantitative gait parameters (fore and hind limb duty factor imbalance, right and left paw placement accuracy). Although we did not observe any direct reconnection of the transplanted cells with the host tissue, we did observe neurofilament fibers extending from the host tissue into the scaffold. Importantly, the mechanism for improved functional outcomes is likely an increase in trophic support from subcutaneously maturing the scaffold, which is enhanced by the administration of ISP.
FRAT1 Enhances the Proliferation and Tumorigenesis of CD133(+) Nestin(+) Glioma Stem Cells In Vitro and In Vivo
JOURNAL OF CANCER
Authors: Guo, Geng; Liu, Jing; Ren, Yeqing; Mao, Xinggang; Hao, Yining; Zhong, Chengliang; Chen, Xiaolin; Wang, Xiaogang; Wu, Yongqiang; Lian, Shizhong; Mei, Lin; Zhao, Yuanli
Abstract
Glioma stem cells (GSCs) are considered the source for development, recurrence, and poor prognosis of glioma, so treatment targeted GSCs is of great interest. The frequently rearranged in advanced T cell lymphomas-1 (FRAT1) gene is an important member of the Wnt/beta-catenin signaling transduction pathway, and aberrantly activation of Wnt signaling has been identified to contribute to the tumorigenesis, proliferation, invasion of a variety kinds of cancer stem cells. However, correlations between FRAT1 and GSCs and the specific mechanisms remain unclear. In this study, we aimed to investigate the effect of FRAT1 on GSCs proliferation, colony formation, sphere formation and tumorigenesity in vitro and in vivo and its underlying mechanism. Lentiviral transfection was used to construct GSCs with low FRAT1 expression. The expression of FRAT1 on GSCs proliferation in vitro was assessed by cell counting kit-8(CCK-8). Colony formation and sphere formation assays were conducted to assess the colony and sphere formation ability of GSCs. Then, an intracranial glioma nude mouse model was built to measure the effect of low FRAT1 expression on GSCs proliferation and tumorigenesity in vivo. Real-time PCR, Western blot, and Immunohistochemistry were processed to detect the mRNA and protein expressions of FRAT1, beta-catenin in the glioma tissue of xenograft mice to study their correlations. The functional assays verifed that low FRAT1 expression inhibited CD133(+)Nestin(+) GSCs proliferation, colony formation, sphere formation ability in vitro. In vivo GSCs xenograft mice model showed that low FRAT1 expression suppressed the proliferation and tumorigenesity of CD133(+)Nestin(+) GSCs and reduced beta-catenin mRNA and protein expression. Furthermore, the expression of FRAT1 and beta-catenin were positively correlated. Altogether, results indicate that FRAT1 enhances the proliferation, colony formation, sphere formation and tumorigenesity of CD133(+)Nestin(+) glioma stem cells in vitro and in vivo as well as the expression of beta-catenin. Therefore, inhibiting proliferation of GSCs and FRAT1 may be a molecular target to GSCs in treating human glioma in the future.