Differential Properties of Human ALP+ Periodontal Ligament Stem Cells vs Their ALP- Counterparts

Abstract

Characterizing subpopulations of stem cells is important to understand stem cell properties. Tissue-nonspecific alkaline phosphatase (ALP) is associated with mineral tissue forming cells as well as stem cells. Information regarding ALP subpopulation of human periodontal ligament stem cells (hPDLSCs) is limited. In the present study, we examined ALP+ and ALP− hPDLSC subpopulations, their surface markers STRO-1 and CD146, and the expression of stemness genes at various cell passages. We found that ALP+ subpopulation had higher levels of STRO-1 (30.6 ± 5.6%) and CD146 (90.4 ± 3.3%) compared to ALP− (STRO-1: 0.5 ± 0.1%; CD146: 75.3 ± 7.2%). ALP+ cells expressed significantly higher levels of stemness associated genes, NANOG, OCT4 and SOX than ALP− cells at low cell passages of 2-3 (p<0.05). ALP+ and ALP− cells had similar osteogenic, chondrogenic and neurogenic potential while ALP−, not ALP+ cells, lacked adipogenic potential. Upon continuous culturing and passaging, ALP+ continued to express higher stemness genes and STRO-1 and CD146 than ALP− cells at ≥passage 19. Under conditions (over-confluence and vitamin C treatment) when ALP+ subpopulation was increased, the stemness gene levels of ALP+ was no longer significantly higher than those in ALP− cells. In conclusion, ALP+ hPDLSCs possess differential properties from their ALP− counterparts.

Cementogenic genes in human periodontal ligament stem cells are downregulated in response to osteogenic stimulation while upregulated by vitamin C treatment

“…The ALP + cells were collected from the column after adding the buffer and firmly pushing the plunger into the column. We found that using FACS or MACS yielded similar results (Yu et al 2015). In the present study, FACS was used for the data in Figs.…”

“…The patient sample collection in this study was based on approved exempt protocols by the Institutional Review Board (IRB) of BU (#H-28882) and UTHSC (12-01937-XM); no patient consents were needed. The tissues were minced into 1 × 1 × 1 mm fragments, digested in collagenase/dispase and filtered through a 70-µm strainer to obtain single-cell suspensions as described previously (Huang et al 2010; Seo et al 2004; Yu et al 2015). Seeded cells were grown in α-minimum essential medium (α-MEM; Life Technologies/GIBCO BRL, Gaithersburg, MD, USA) supplemented with 10 % fetal bovine serum (FBS), 2 mM L-Glutamine, 100 µM L-ascorbic acid-2-phosphate and antibiotic/antimycotic agents as the regular growth medium (GM; pH 8.1); and maintained under 5 % CO2 at 37 °C.…”

“…The PDL harbors periodontal ligament stem cells (PDLSCs) (Seo et al 2004) that have been shown to express typical mesenchymal stem cell (MSC) markers such as STRO-1, CD13, CD29, CD44, CD59, CD90, CD146 and CD105 (Huang et al 2009; Yu et al 2015). PDLSCs form colony-forming unit-fibroblasts (CFU-Fs) with the potential to differentiate into multiple cell lineages in cultures as well as generate ectopic cementum-/PDL-like tissues in vivo (Gay et al 2007; Huang et al 2009; Seo et al 2004; Yu et al 2015). PDLSCs have the capacity to regenerate periodontium thereby restoring periodontal defects, as demonstrated in large animal studies such as swine using either an autologous or allogenic cell source (Ding et al 2010; Liu et al 2008; Menicanin et al 2014).…”

Human dental stem cell derived transgene‐free iPSCs generate functional neurons via embryoid body‐mediated and direct induction methods

“…Expression of neurogenic genes was analyzed by real-time quantitative (q)PCR according to previous reports (Gauthier , et al , 2017, Yu , et al , 2015). Briefly, total RNA was extracted using an RNeasy Mini Kit (Qiagen, Valencia, CA).…”

MicroRNA-29a-3p enhances dental implant osseointegration of hyperlipidemic rats via suppressing dishevelled 2 and frizzled 4

“…Xu et al [ 9 ] demonstrated that BMSCs transplantation significantly enhanced new bone formation, but hyperlipidemia compromised homing efficiency of systematically transplanted BMSCs and inhibited bone regeneration. Alkaline phosphatase (ALP), engaged in bone matrix mineralization, and runt-related transcription factor 2 (Runx2), a master transcription factor of osteogenesis, were considered as early marker genes of osteogenesis [ 10 – 17 ].…”