Aggregation of Human Eyelid Adipose-derived Stem Cells by Human Body Fluids

Enhanced Expansion of Human Pluripotent Stem Cells and Somatic Cell Reprogramming Using Defined and Xeno-Free Culture Conditions

Human embryonic stem cells and induced pluripotent stem cells (hPSC) have an unprecedented opportunity to revolutionize the fields of developmental biology as well as tissue engineering and regenerative medicine. However, their applications have been significantly limited by the lack of chemically defined and xeno-free culture conditions. The demand for the high-quality and scaled-up production of cells for use in both research and clinical studies underscores the need to develop tools that will simplify the in vitro culture process while reducing the variables. Here, we describe a systematic study to identify the optimal conditions for the initial cell attachment of hPSC to tissue culture dishes grafted with polymers of N-(3-Sulfopropyl)-N-Methacryloxyethyl-N, N-Dimethylammoniun Betaine (PMEDSAH) in combination with chemically defined and xeno-free culture media. After testing multiple supplements and chemicals, we identified that pre-conditioning of PMEDSAH grafted plates with 10% human serum (HS) supported the initial cell attachment, which allowed for the long-term culture and maintenance of hPSC compared to cells cultured on Matrigel-coated plates. Using this culture condition, a 2.1-fold increase in the expansion of hPSC was observed without chromosomal abnormalities. Furthermore, this culture condition supported a higher reprogramming efficiency (0.37% vs. 0.22%; p < 0.0068) of somatic cells into induced pluripotent stem cells compared to the non-defined culture conditions. This defined and xeno-free hPSC culture condition may be used in obtaining the large populations of hPSC and patient-derived iPSC required for many applications in regenerative and translational medicine.

Involvement of cAMP in the Human Serum-Induced Migration of Adipose-Derived Stem Cells

Previously we observed that human adipose-derived stem cells (hADSCs) could form aggregation during culture in the presence of human serum (HS). In the present study, we have examined if the aggregation might result from the cell migration and analyzed the difference of cell adhesivity after culture in various conditions. When cells were cultured in fetal bovine serum (FBS) alone, there was no morphological change. Similarly, cells pretreated with FBS for 1 day or cultured in a mixture of FBS and HS showed little change. In contrast, cells cultured in HS alone exhibited formation of cell-free area (spacing) and/or cell aggregation. When cells cultured in FBS or pretreated with FBS were treated with 0.06% trypsin, almost cells remained attached to the dish surfaces. In contrast, when cells cultured in HS alone were examined, most cells detached from the dish by the same treatment. Treatment of cells with forskolin, isobutylmethyl xanthine (IBMX) or LY294002 inhibited the formation of spacing whereas H89 or Y27632 showed little effect. When these cells were treated with 0.06% trypsin after culture, most cells detached from the dishes as cells cultured in HS alone did. However, cells treated with IBMX exhibited weaker adhesivity than HS alone. Based on these observations, it is suggested that HS treatment might decrease the adhesivity and induce three-dimensional migration of hADSCs, in the latter of which cAMP signaling could be involved.

Expression of tight junction molecule in the human serum-induced aggregation of human abdominal adipose-derived stem cells in vitro

Previously we have shown that human abdominal adipose derived-stem cells (ADSCs) could aggregate during the high-density culture in the presence of human serum (HS). In the present study, we observed that human cord blood serum (CBS) and follicular fluid (HFF) also induced aggregation. Similarly, porcine serum could induce aggregation whereas bovine and sheep sera induced little aggregation. qRT-PCR analyses demonstrated that, compared to FBS-cultured ADSCs, HScultured cells exhibited higher level of mRNA expression of CLDN3, -6, -7, -15, and -16 genes among the tight junction proteins. ADSCs examined at the time of aggregation by culture with HS, BSA, HFF, CBS, or porcine serum showed significantly higher level of mRNA expression of JAM2 among JAM family members. In contrast, cells cultured in FBS, bovine serum or sheep serum, showed lower level of JAM2 expression. Immunocytochemical analyses demonstrated that the aggregates of HS-cultured cells (HS-Agg) showed intense staining against the anti-JAM2 antibody whereas neither non-aggregated cells (HS-Ex) nor FBS-cultured cells exhibited weak staining. Western blot results showed that HS-Agg expressed JAM2 protein more prominently than HS-Ex and FBS-cultured cells, both of latter reveled weaker intensity. These results suggest that the aggregation property of ADSCs during high-density culture would be dependent on the specific components of serum, and that JAM2 molecule could play a role in the animal sera-induced aggregation in vitro.

Expression of Tight Junction Molecule In The Human Serum-Induced Aggregation of Human Abdominal Adipose-Derived Stem Cells In Vitro

Previously we have shown that human abdominal adipose derived-stem cells (ADSCs) could aggregate during the high-density culture in the presence of human serum (HS). In the present study, we observed that human cord blood serum (CBS) and follicular fluid (HFF) also induced aggregation. Similarly, porcine serum could induce aggregation whereas bovine and sheep sera induced little aggregation. qRT-PCR analyses demonstrated that, compared to FBS-cultured ADSCs, HScultured cells exhibited higher level of mRNA expression of CLDN3, -6, -7, -15, and -16 genes among the tight junction proteins. ADSCs examined at the time of aggregation by culture with HS, BSA, HFF, CBS, or porcine serum showed significantly higher level of mRNA expression of JAM2 among JAM family members. In contrast, cells cultured in FBS, bovine serum or sheep serum, showed lower level of JAM2 expression. Immunocytochemical analyses demonstrated that the aggregates of HS-cultured cells (HS-Agg) showed intense staining against the anti-JAM2 antibody whereas neither non-aggregated cells (HS-Ex) nor FBS-cultured cells exhibited weak staining. Western blot results showed that HS-Agg expressed JAM2 protein more prominently than HS-Ex and FBS-cultured cells, both of latter reveled weaker intensity. These results suggest that the aggregation property of ADSCs during high-density culture would be dependent on the specific components of serum, and that JAM2 molecule could play a role in the animal sera-induced aggregation in vitro.

A role of cell adhesion molecules and gelatinases in human serum-induced aggregation of human eyelid-derived stem cells in vitro

Human serum (HS) has been reported to induce aggregation of human eyelid adipose-derived stem cells (HEACs) during high-density culture in vitro. The present study focused on the role of cell adhesion molecules and gelatinases during HS-induced aggregation of HEACs. HS-induced aggregation occurred between 9-15 days of culture. Cells aggregated by HS medium (HS-agg) showed stronger expression of α2, α2B, αX, and CEACAM1 genes compared to non-aggregated cells in HS medium (HS-ex) or in control FBS-cultured cells. HS-agg were distinctly labeled with antibodies against α2, α2B, and αX proteins. Western blot results demonstrated that the two integrin proteins were greatly expressed in HS-agg compared to HS-ex and control FBS-cultured cells. Treatment of HEACs with anti-integrin α2 antibody during culture in HS medium delayed aggregation formation. HS-agg exhibited strong expression of MMP1 and MMP9 compared to HS-ex or FBS-cultured cells. Conditioned media from HS-culture showed remarkable increase of MMP9 gelatinolytic activity in comparison to those from FBS-culture. However, there was no change of TIMP mRNA expression in relation to the HS-induced aggregation. Based on these results, it is suggested that integrin α2, α2B, and αX, and MMP9 might play an important role in the HS-induced aggregation of HEACs.