scholarly journals Dorsal Root Ganglion Maintains Stemness of Bone Marrow Mesenchymal Stem Cells by Enhancing Autophagy through the AMPK/mTOR Pathway in a Coculture System

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Shuaishuai Zhang ◽  
Junqin Li ◽  
Huijie Jiang ◽  
Yi Gao ◽  
Pengzhen Cheng ◽  
...  

Our previous studies found that sensory nerve tracts implanted in tissue-engineered bone (TEB) could result in better osteogenesis. To explore the mechanism of the sensory nerve promoting osteogenesis in TEB in vitro, a transwell coculture experiment was designed between dorsal root ganglion (DRG) cells and bone marrow mesenchymal stem cells (BMSCs). BMSC proliferation was determined by CCK8 assay, and osteo-, chondro-, and adipogenic differentiation were assessed by alizarin red, alcian blue, and oil red staining. We found that the proliferation and multipotent differentiation of BMSCs were all enhanced in the coculture group compared to the BMSCs group. Crystal violet staining showed that the clone-forming ability of BMSCs in the coculture group was also enhanced and mRNA levels of Sox2, Nanog, and Oct4 were significantly upregulated in the coculture group. Moreover, the autophagy level of BMSCs, regulating their stemness, was promoted in the coculture group, mediated by the AMPK/mTOR pathway. In addition, AMPK inhibitor compound C could significantly downregulate the protein expression of LC3 and the mRNA level of stemness genes in the coculture group. Finally, we found that the NK1 receptor antagonist, aprepitant, could partly block this effect, which indicated that substance P played an important role in the effect. Together, we conclude that DRG could maintain the stemness of BMSCs by enhancing autophagy through the AMPK/mTOR pathway in a transwell coculture system, which may help explain the better osteogenesis after implantation of the sensory nerve into TEB.

2019 ◽  
Vol 39 (3) ◽  
Author(s):  
Ying Chen ◽  
Yu-Run Yang ◽  
Xiao-Liang Fan ◽  
Peng Lin ◽  
Huan Yang ◽  
...  

AbstractOsteoblast-mediated bone formation is a complex process involving various pathways and regulatory factors, including cytokines, growth factors, and hormones. Investigating the regulatory mechanisms behind osteoblast differentiation is important for bone regeneration therapy. miRNAs are known as important regulators, not only in a variety of cellular processes, but also in the pathogenesis of bone diseases. In the present study, we investigated the potential roles of miR-206 during osteoblast differentiation. We report that miR-206 expression was significantly down-regulated in human bone marrow mesenchymal stem cells (BMSCs) at days 7 and 14 during osteogenic induction. Furthermore, miR-206 overexpressing BMSCs showed attenuated alkaline phosphatase (ALP) activity, Alizarin Red staining, and osteocalcin secretion. The mRNA levels of osteogenic markers, Runx2 and Osteopontin (OPN), were significantly down-regulated in miR-206 overexpressing BMSCs. We observed that significantly increased glutamine uptake at days 7 and 14 during the osteogenic induction and inhibition of glutamine metabolism by knocking down glutaminase (GLS)-suppressed osteogenic differentiation of BMSCs. Here, we discover that miR-206 could directly bind to the 3′-UTR region of GLS mRNA, resulting in suppressed GLS expression and glutamine metabolism. Finally, restoration of GLS in miR-206 overexpressing BMSCs led to recovery of glutamine metabolism and osteogenic differentiation. In summary, these results reveal a new insight into the mechanisms of the miR-206-mediated osteogenesis through regulating glutamine metabolism. Our study may contribute to the development of therapeutic agents against bone diseases.


Molecules ◽  
2019 ◽  
Vol 24 (2) ◽  
pp. 271
Author(s):  
Shan Liu ◽  
Zhuo-Hui Luo ◽  
Gui-Mei Ji ◽  
Wei Guo ◽  
Jia-Zhong Cai ◽  
...  

Cajanolactone A (CLA) is a stilbenoid discovered by us from Cajanus cajan (L.) Millsp. In our study, CLA was found to promote osteoblast differentiation in human bone marrow mesenchymal stem cells (hBMSCs), as judged by increased cellular alkaline phosphatase activity and extracellular calcium deposits, and elevated protein expression of Runx2, collagen-1, bone morphogenetic protein-2, and osteopontin. Mechanistic studies revealed that hBMSCs undergoing osteoblast differentiation expressed upregulated mRNA levels of Wnt3a, Wnt10b, LRP5/6, Frizzled 4, β-catenin, Runx2, and Osterix from the early stage of differentiation, indicating the role of activated Wnt/β-catenin signaling pathway in osteoblast differentiation. Addition of CLA to the differentiation medium further increased the mRNA level of Wnt3a, Wnt10b, Frizzled 4, LRP5, and β-catenin, inferring that CLA worked by stimulating Wnt/LRP5/β-catenin signaling. Wnt inhibitor dickkopf-1 antagonized CLA-promoted osteoblastogenesis, indicating that CLA did not target the downstream of canonical Wnt signaling pathway. Treatment with CLA caused no changes in mRNA expression level, as well as protein secretion of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL), indicating that CLA did not affect the OPG/RANKL axis. Our results showed that CLA, which promoted osteoblast differentiation in hBMSCs, through activating Wnt/LRP5/β-catenin signaling transduction, is a promising anti-osteoporotic drug candidate.


2020 ◽  
Vol 10 (2) ◽  
pp. 246-251
Author(s):  
Wenxiao Jiang ◽  
Yijun Zhang ◽  
Ye Huang ◽  
Yunfeng Cheng ◽  
Zhigang Liu

Hepatic kinase B1 (LKB1) is a tumor suppressor and regulates cell proliferation and apoptosis. However, whether LKB1 affects bone marrow mesenchymal stem cells (BMSCs) osteogenic differentiation of during aging remains unclear. Two BMSCs derived from Zempster24−/− (aging) and Zempster24+/+ (normal) mice were cultured in vitro followed by measurement of LKB1 expression by real-time quantitative PCR and Western blot. LKB1 siRNA was transfected into Zempster24−/−BMSCs and LKB1 expression was measured. 14 days after osteogenic induction, mineralized nodule formation was evaluated by alizarin red staining, expression of Calcin, type I collagen, RUNX2 and OPN mRNA expression was measured, together with alkaline phosphatase (ALP) activity and the PI3K/mTOR pathway activity. Compared with normal BMSCs, LKB1 expression was significantly increased, calcified nodules were decreased, with reduced expression of osteocalcin, type I collagen, RUNX2 and OPN mRNA as well as decreased ALP activity and PI3K/mTOR signaling protein expression (P < 0.05). LKB1 siRNA transfection into senescent BMSCs down-regulated LKB1 expression, increased calcification nodule formation, expression of osteocalcin, type I collagen, RUNX2 and OPN mRNA, as well as increased ALP activity and PI3K/mTOR pathway protein expression (P < 0.05). Aging can promote the increase of LKB1 expression and inhibit the osteogenic differentiation of BMSCs. Down-regulation of LKB1 expression in BMSCs during senescence can promote osteogenic differentiation through regulating PI3K/mTOR pathway.


2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Xiaoming Zhang ◽  
Fei Hua ◽  
Ziying Yang ◽  
Yueqiu Chen ◽  
Xiaomei Teng ◽  
...  

Objective. The study aim to investigate the role of microRNA-155 (miR-155) on the immunoregulatory function of bone marrow mesenchymal stem cells (MSCs). Methods. MSCs were isolated from 2-week-old Sprague-Dawley rats and identified by flow cytometry using anti-CD29, anti-CD44, anti-CD34, and anti-CD45 antibodies. MSCs were transfected with miR155-mimics, miR155-inhibitor, and control oligos, respectively, and then cocultured with spleen mononuclear cells (SMCs). The mRNA levels of Th1, Th2, Th17, and Treg cell-specific transcription factors (Tbx21, Gata3, Rorc, and Foxp3, resp.) and the miR-155 target gene SOCS1 were detected by quantitative real-time PCR (qPCR) in SMCs. The proportion of CD4+ FOXP3+ Treg cells was detected by flow cytometry. In addition, the effects of MSCs transfected with miR-155 on the migration of rat SMCs were investigated by transwell chamber. Results. CD29 and CD44 were expressed in MSCs, while CD34 and CD45 were negative. The percentage of CD4+ FOXP3+ Treg cells in the SMC population was significantly higher compared with that noted in SMCs control group (p<0.001) following 72 hours of coculture with miR155-mimics-transfected SMCs. In contrast, the percentage of CD4+ FOXP3+ Treg cells in the SMCs cocultured with miR155-inhibitor-transfected MSCs was significantly lower compared with that noted in SMCs control group (p<0.001). MiR155-mimics-transfected MSCs inhibited the expression of Tbx21, Rorc, and SOCS1, while the expression of Gata3 and Foxp3 was increased. In contrast to the downregulation of the aforementioned genes, miR155-inhibitor-transfected MSCs resulted in upregulation of Tbx21, Rorc, and SOCS1 expression levels and inhibition of Gata3 and Foxp3. In the transwell assay, miR155-mimics-transfected MSCs exhibited lower levels of SMCs migration, while the miR155-inhibitor-transfected MSCs demonstrated significantly higher levels of migration, compared with the blank control group (p<0.01, resp.). Conclusion. miR-155 favors the differentiation of T cells into Th2 and Treg cells in MSCs, while it inhibits the differentiation to Th1 and Th17 cells.


2012 ◽  
Vol 15 (2) ◽  
pp. 1661-1665
Author(s):  
Marina Burgos-Silva ◽  
Cassiano Donizetti-Oliveira ◽  
Marco Antonio Cenedeze ◽  
Denise Maria Avancini Costa Malheiros ◽  
Marlene Antônia dos Reis ◽  
...  

Acute kidney injury constitutes a syndrome responsible by a major percentage of acute kidney failures and it continues being associated to high mortality rates. Induced mainly by ischemia-reperfusion injury and nephrotoxic drugs, this condition is marked by a decrease in organ function and histopathological pattern of acute tubular necrosis. In search of more efficient therapies, a great deal of attention has been given to the therapeutic use of stem cells to treat kidney injuries. Bone marrow stem cells in particular have received a great attention due to its immunomodulatory properties, and its therapeutic mechanisms are intensely being studied in the literature. Purpose: In view of recent findings, the aim of our research was to get a better understanding on the potential role of bone marrow mesenchymal stem cells in a murine model of acute nephotoxicity induced by folic acid. Methods: C57Bl/6j mice (8 weeks) were submitted to acute kidney injury by folic acid (200mg/kg) administered intraperitoneally. After 24 hours, mice received mesenchymal stem cells (5.105 cells per animal) through retro-orbital intravenous injection. Mice were sacrificed after 24 hours and blood and kidneys were harvested for analysis. Results: Stem cell treatment conferred functional improvement seen through lower creatinine and urea serum levels in 8 week old C57Bl/6j mice in comparison to mice treated only with folic acid (200mg/kg body weight). This amelioration are also correlated to down regulation of kidney pro-inflammatory cytokine mRNA levels as TNF-a, IL-6 and IL-1b in stem cell treated mice. In addition, treated mice demonstrated higher levels of immunostaining for proliferating cell nuclear antigen and a tendency towards a higher Bcl-2/Bax mRNA ratio, indicating higher tissue regeneration and protection against injury-induced apoptosis. Conclusion: These results indicate bone marrow stem cells as an efficient tool in nephrotoxic kidney injury treatment.  


2013 ◽  
Author(s):  
Melo Ocarino Natalia de ◽  
Silvia Silva Santos ◽  
Lorena Rocha ◽  
Juneo Freitas ◽  
Reis Amanda Maria Sena ◽  
...  

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