Differential Proteomic Analysis of Human Placenta-Derived Mesenchymal Stem Cells Cultured on Normal Tissue Culture Surface and Hyaluronan-Coated Surface

Increased proliferation and differentiation capacity of placenta-derived mesenchymal stem cells from women of median maternal age correlates with telomere shortening

Mesenchymal stem cells (MSCs) experience functional decline with systemic aging, resulting in reduced proliferation, increased senescence, and lower differentiation potential. The placenta represents a valuable source of MSCs, but the possible effect of donor age on the properties of placenta-derived mesenchymal stem cells (PDMSCs) has not been thoroughly studied. Thus, the aim of this study was to underscore the effect of maternal age on the biological characteristics and stemness properties of PDMSCs. PDMSCs were isolated from 5 donor age groups (A: 18-21, B: 22-25, C: 26-30, D:31-35 and E: ≥36 years) for comparison of morphological, proliferative and differentiation properties. The pluripotency markers NANOG, OCT4, and SSEA4, as well as multipotency and differentiation markers, showed higher expression in PDMSCs from mothers aged 22-35 years, with up to a 7-fold increase in adipogenesis. Cumulative population doubling, cell growth curves, and colony-forming unit-fibroblast assays revealed higher self-renewal ability in donors 26-30 years old. An increase in the proliferative characteristics of PDMSCs correlated with increased telomere shortening, suggesting that shorter telomere lengths could be related to cellular division rather than aging. A clear understanding of the effect of maternal age on MSC regenerative potential will assist in increasing the effectiveness of future cell therapies.

Hyaluronan Induces a Mitochondrial Functional Switch in Fast-Proliferating Human Mesenchymal Stem

Background and Objectives

Hyaluronan preserves the proliferation and differentiation potential of mesenchymal stem cells. Supplementation of low-concentration hyaluronan (SHA) in stem cells culture medium increases its proliferative rate, whereas coated-surface hyaluronan (CHA) maintains cells in a slow-proliferating mode. We have previously demonstrated that in CHA, the metabolic proliferative state of stem cells was influenced by upregulating mitochondrial biogenesis and function. However, the effect of SHA on stem cells' energetic status remains unknown. In this study, we demonstrate the effect that low-concentration SHA at 0.001 mg/ml (SHA0.001) and high-concentration SHA at 5 mg/ml (SHA5) exert on stem cells' mitochondrial function compared with CHA and noncoated tissue culture surface (control).

Methods and Results

Fast-proliferating human placenta-derived mesenchymal stem cells (PDMSCs) cultured on SHA0.001 exhibited reduced mitochondrial mass, lower mitochondrial DNA copy number, and lower oxygen consumption rate compared with slow-proliferating PDMSCs cultured on CHA at 5.0 (CHA5) or 30 μg/cm² (CHA30). The reduced mitochondrial biogenesis observed in SHA0.001 was accompanied by a 2-fold increased ATP content and lactate production, suggesting that hyaluronan-induced fast-proliferating PDMSCs may rely less on mitochondrial function as an energy source and induce a mitochondrial functional switch to glycolysis.

Conclusions

PDMSCs cultured on both CHA and SHA exhibited a reduction in reactive oxygen species levels. The results from this study clarify our understandings on the effect of hyaluronan on stem cells and provide important insights into the effect of distinct supplementation methods used during cell therapies.

Interferon-stimulated gene 15 modulates cell migration by interacting with Rac1 and contributes to lymph node metastasis of oral squamous cell carcinoma cells

In an effort to understand the underlying mechanisms of lymph node metastasis in oral squamous cell carcinoma (OSCC), through in vivo selection, LN1-1 cells were previously established from OEC-M1 cells and showed enhanced lymphangiogenesis and lymphatic metastasis capabilities. In the current study, we use a stable isotope labeling with amino acids in cell culture (SILAC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based proteomic platform to compare LN1-1 to OEC-M1 cells. Interferon-stimulated gene 15 (ISG15) was found highly expressed in LN1-1 cells. Immunohistochemical analysis and meta-analysis of publicly available microarray datasets revealed that the ISG15 level was increased in human OSCC tissues and associated with poor disease outcome. Knockdown of ISG15 had minimal effects on tumor growth but did decrease tumor lymphangiogenesis and lymphatic metastasis of LN1-1 cells. Consistent with the in vivo assay, ISG15 knockdown did not impair cell growth but diminished cell migration, invasion, and transendothelial migration in vitro. ISG15-induced cell migration was independent of ISGylation and associated with membrane protrusion. Ectopic expression of ISG15 increased Rac1 activity and knockdown of Rac1 impaired ISG15-enhanced migration. Furthermore, Rac1 colocalized with ISG15 to a region of membrane protrusion and ISG15 coimmunoprecipitated with Rac1, especially with the Rac1-GDP form. Importantly, as shown by proximity ligation assays, ISG15 and Rac1 physically interacted with each other. Our results indicated that ISG15 affects cell migration by interacting with Rac1 and regulating Rac1 activity and contributes to lymphatic metastasis in OSCC.

Laminin γ2-enriched extracellular vesicles of oral squamous cell carcinoma cells enhance in vitro lymphangiogenesis via integrin α3-dependent uptake by lymphatic endothelial cells

Oral squamous cell carcinoma (OSCC) LN1-1 cells previously showed greater capacities for lymphangiogenesis and lymph node metastasis compared to their parental OEC-M1 cells, in addition to an ability to enhance the migration and tube formation of lymphatic endothelial cells (LECs). Purified by a series of differential centrifugations and characterized using electron microscopy, dynamic light scattering and western blot, LN1-1 cell-derived extracellular vesicles (LN1-1 EVs) were shown to promote LEC migration, tube formation and uptake by LECs more effectively than did OEC-M1 cell-derived EVs (OEC-M1 EVs). Using stable isotope labeling with amino acids in cell culture/liquid chromatography-tandem mass spectrometry-based proteomic platform, the laminin-332 proteins, including laminin α3, β3 and γ2, were validated as highly expressed proteins in LN1-1 EVs. Clinically, a higher level of laminin-332 was detected in plasma EVs from OSCC patients with lymph node metastasis than in both healthy controls and OSCC patients without lymphatic metastasis, suggesting EV-borne laminin-332 as a novel and noninvasive biomarker for the detection of lymph node metastasis in OSCC. The knockdown of laminin γ2 and inhibition by anti-laminin-332 neutralizing antibodies impaired LN1-1 EV-mediated LEC migration, tube formation and uptake by LECs. Importantly, laminin γ2-deficient EVs showed a reduced ability to drain into lymph nodes in comparison with the control EVs. In addition, the laminin 332/γ2-mediated EV uptake was dependent on integrin α3 but not β1, β4 or α6. Collectively, the uptake of laminin γ2-enriched EVs by LECs enhanced in vitro lymphangiogenesis and EV-borne laminin-332 is thus a viable biomarker for OSCC.

Hyaluronan keeps mesenchymal stem cells quiescent and maintains the differentiation potential over time

Hyaluronan (HA), an abundant polysaccharide found in human bodies, plays a role in the mesenchymal stem cells (MSCs) maintenance. We had previously found that HA prolonged the lifespan, and prevented the cellular aging of murine adipose-derived stromal cells. Recently, we had also summarized the potential pathways associated with HA regulation in human MSCs. In this study, we used the human placenta-derived MSCs (PDMSC) to investigate the effectiveness of HA in maintaining the PDMSC. We found that coating the culture surface coated with 30 μg cm^-2 of HA (C) led to cluster growth of PDMSC, and maintained a higher number of PDMSC in quiescence compared to those grown on the normal tissue culture surface (T). PDMSC were treated for either 4 (short-term) or 19 (long-term) consecutive passages. PDMSC which were treated with HA for 19 consecutive passages had reduced cell enlargement, preserved MSCs biomarker expressions and osteogenic potential when compared to those grown only on T. The PDMSC transferred to T condition after long-term HA treatment showed preserved replicative capability compared to those on only T. The telomerase activity of the HA-treated PDMSC was also higher than that of untreated PDMSC. These data suggested a connection between HA and MSC maintenance. We suggest that HA might be regulating the distribution of cytoskeletal proteins on cell spreading in the event of quiescence to preserve MSC stemness. Maintenance of MSCs stemness delayed cellular aging, leading to the anti-aging phenotype of PDMSC.