Stem Cells

Chen, Lu; Wang, Xiping; Tian, Sha; Zhou, Linxi; Wang, Li; Liu, Xiaohan; Yang, Zihan; Fu, Guiqiang; Liu, Xingguang; Ding, Chen; Zou, Duohong

doi: 10.1093/stmcls/sxae047pmid: 39169713

Human dental pulp stem cells (HDPSCs) showed an age-dependent decline in proliferation and differentiation capacity. Decline in proliferation and differentiation capacity affects the dental stromal tissue homeostasis and impairs the regenerative capability of HDPSCs. However, which age-correlated proteins regulate the senescence of HDPSCs remain unknown. Our study investigated the proteomic characteristics of HDPSCs isolated from subjects of different ages and explored the molecular mechanism of age-related changes in HDPSCs. Our study showed that the proliferation and osteogenic differentiation of HDPSCs were decreased, while the expression of aging-related genes (p21, p53) and proportion of senescence-associated β-galactosidase (SA-β-gal)-positive cells were increased with aging. The bioinformatic analysis identified that significant proteins positively correlated with age were enriched in response to the mammalian target of rapamycin (mTOR) signaling pathway (ILK, MAPK3, mTOR, STAT1, and STAT3). We demonstrated that OSU-T315, an inhibitor of integrin-linked kinase (ILK), rejuvenated aged HDPSCs, similar to rapamycin (an inhibitor of mTOR). Treatment with OSU-T315 decreased the expression of aging-related genes (p21, p53) and proportion of SA-β-gal-positive cells in HDPSCs isolated from old (O-HDPSCs). Additionally, OSU-T315 promoted the osteoblastic differentiation capacity of O-HDPSCs in vitro and bone regeneration of O-HDPSCs in rat calvarial bone defects model. Our study indicated that the proliferation and osteoblastic differentiation of HDPSCs were impaired with aging. Notably, the ILK/AKT/mTOR/STAT1 signaling pathway may be a major factor in the regulation of HDPSC senescence, which help to provide interventions for HDPSC senescence.

Jacques, Virginie; Benaouadi, Sabrina; Descamps, Jean-Gerard; Reina, Nicolas; Espagnolle, Nicolas; Marsal, Dimitri; Sainte-Marie, Yannis; Boudet, Alexandre; Pinto, Carla; Farge, Thomas; Savagner, Frédérique

doi: 10.1093/stmcls/sxae050

Li, Yue; Ren, Miao; Li, Hu; Zhang, Zuo; Yuan, Ke; Huang, Yujin; Yuan, Shengnan; Ju, Wen; He, Yuan; Xu, Kailin; Zeng, Lingyu

doi: 10.1093/stmcls/sxae046pmid: 38995653

Efficient homing of infused hematopoietic stem and progenitor cells (HSPCs) into the bone marrow (BM) is the prerequisite for successful hematopoietic stem cell transplantation. However, only a small part of infused HSPCs find their way to the BM niche. A better understanding of the mechanisms that facilitate HSPC homing will help to develop strategies to improve the initial HSPC engraftment and subsequent hematopoietic regeneration. Here, we show that irradiation upregulates the endomucin expression of endothelial cells in vivo and in vitro. Furthermore, depletion of endomucin in irradiated endothelial cells with short-interfering RNA (siRNA) increases the HSPC-endothelial cell adhesion in vitro. To abrogate the endomucin of BM sinusoidal endothelial cells (BM-SECs) in vivo, we develop a siRNA-loaded bovine serum albumin nanoparticle for targeted delivery. Nanoparticle-mediated siRNA delivery successfully silences endomucin expression in BM-SECs and improves HSPC homing during transplantation. These results reveal that endomucin plays a critical role in HSPC homing during transplantation and that gene-based manipulation of BM-SEC endomucin in vivo can be exploited to improve the efficacy of HSPC transplantation.

Sun, Zhiyuan; Shan, Xinqi; Fan, Chun’e; Liu, Lutao; Li, Shuai; Wang, Jiahui; Zhou, Na; Zhu, Minsheng; Chen, Huaqun

doi: 10.1093/stmcls/sxae048pmid: 39097775

It has been documented that caspase 3 activity is necessary for skeletal muscle regeneration, but how its activity is regulated is largely unknown. Our previous report shows that intracellular TMEM16A, a calcium activated chloride channel, significantly regulates caspase 3 activity in myoblasts during skeletal muscle development. By using a mouse line with satellite cell (SC)-specific deletion of TMEM16A, we examined the role of TMEM16A in regulating caspase 3 activity in SC (or SC-derived myoblast) as well as skeletal muscle regeneration. The mutant animals displayed apparently impaired regeneration capacity in adult muscle along with enhanced ER stress and elevated caspase 3 activity in Tmem16a−/− SC derived myoblasts. Blockade of either excessive ER stress or caspase 3 activity by small molecules significantly restored the inhibited myogenic differentiation of Tmem16a−/− SCs, indicating that excessive caspase 3 activity resulted from TMEM16A deletion contributes to the impaired muscle regeneration and the upstream regulator of caspase 3 was ER stress. Our results revealed an essential role of TMEM16A in satellite cell-mediated skeletal muscle regeneration by ensuring a moderate level of caspase 3 activity.

Di, Tiankai; Wang, Liying; Cheng, Baixiang; Guo, Mingzhu; Feng, Chao; Wu, Zhenzhen; Wang, Lulu; Chen, Yujiang

doi: 10.1093/stmcls/sxae051pmid: 39167061

BackgroundThis study aims to address challenges in dental pulp regeneration therapy. The heterogeneity of DPSCs poses challenges, especially in stem cell transplantation for clinical use, particularly when sourced from donors of different ages and conditions.MethodsPseudotime analysis was employed to analyze single-cell sequencing data, and immunohistochemical studies were conducted to investigate the expression of fibronectin 1 (FN1). We performed in vitro sorting of PDGFRβ+ DPSCs using flow cytometry. A series of functional assays, including cell proliferation, scratch, and tube formation assays, were performed to experimentally validate the vasculogenic capabilities of the identified PDGFRβ+ DPSC subset. Furthermore, gene-edited mouse models were utilized to demonstrate the importance of PDGFRβ+ DPSCs. Transcriptomic sequencing was conducted to compare the differences between PDGFRβ+ DPSCs and P1-DPSCs.ResultsSingle-cell sequencing analysis unveiled a distinct subset, PDGFRβ+ DPSCs, characterized by significantly elevated FN1 expression during dental pulp development. Subsequent cell experiments demonstrated that this subset possesses remarkable abilities to promote HUVEC proliferation, migration, and tube formation. Gene-edited mouse models confirmed the vital role of PDGFRβ+ DPSCs in dental pulp development. Transcriptomic sequencing and in vitro experiments demonstrated that the PDGFR/PI3K/AKT signaling pathway is a crucial factor mediating the proliferation rate and pro-angiogenic properties of PDGFRβ+ DPSCs.ConclusionWe defined a new subset, PDGFRβ+ DPSCs, characterized by strong proliferative activity and pro-angiogenic capabilities, demonstrating significant clinical translational potential.