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Ji-Ye Cai

Publications and source records attributed to Ji-Ye Cai.

8 recordsLinked to original sources
PubMed2006

Hepatic differentiation of mouse ES cells into BE cells in vitro.

To date, the hepatic differentiation of embryonic stem (ES) cells into biliary epithelial (BE) cells has only been identified in hepatocytes. In this study, an attempt was made to induce the differentiation of ES cells to BE cells. In order to induce hepatic, and then BE cell differentiation, growth factors such as TGF, FGF, HGF and EGF were added to the culture medium supplied to embryonic bodies (EBs) that were derived from ES cells. The marker genes and corresponding proteins of hepatocytes and BE cells such as AFP, ALB, CK8, CK18, CK7, CK19 and GGT, etc. were detected by reverse transcriptase-polymerase chain reaction (RT-PCR), immunocytochemistry (ICC) and enzymatic histochemistry. Lastly, the ratio of BE-like cells to all EBs cells was analyzed and determined by flow cytometry (FCM). Hepatocyte and BE cell marker genes and proteins were found to be expressed in the cytoplasm of differentiated cells. On day 10 of differentiation, many round structures appeared in the EBs culture system and the marker proteins of BE cells were found to be expressed in these structures. The BE cell differentiation ratio continually increased from its initial value of 1.7% on day 13 to 7.4% on day 21. ES cells were found to be able to differentiate into BE cells when cultured using medium with appropriate cell growth factors. These BE cells may be a novel source of differentiated cell types for liver engineering.

Animals↗
PubMed2006

Atomic force microscopy-based cell nanostructure for ligand-conjugated quantum dot endocytosis.

While it has been well demonstrated that quantum dots (QDs) play an important role in biological labeling both in vitro and in vivo, there is no report describing the cellular nanostructure basis of receptor-mediated endocytosis. Here, nanostructure evolution responses to the endocytosis of transferrin (Tf)-conjugated QDs were characterized by atomic force microscopy (AFM). AFM-based nanostructure analysis demonstrated that the Tf-conjugated QDs were specifically and tightly bound to the cell receptors and the nanostructure evolution is highly correlated with the cell membrane receptor-mediated transduction. Consistently, confocal microscopic and flow cytometry results have demonstrated the specificity and dynamic property of Tf-QD binding and internalization. We found that the internalization of Tf-QD is linearly related to time. Moreover, while the nanoparticles on the cell membrane increased, the endocytosis was still very active, suggesting that QD nanoparticles did not interfere sterically with the binding and function of receptors. Therefore, ligand-conjugated QDs are potentially useful in biological labeling of cells at a nanometer scale.

Cell Line, Tumor↗
PubMed2005

[Directed differentiation of Balb/C mouse embryonic stem cells into pancreatic islet-like cell clusters in vitro: observation by atomic force microscope].

OBJECTIVE: To observe the morphological changes of Balb/C mouse embryonic stem cells following directed differentiation into pancreatic islet-like cell clusters (PICC) in vitro using atomic force microscope (AFM). METHODS: Balb/C mouse embryonic stem cells were first cultured into embryonic bodies (EBs) and allowed to differentiate spontaneously for 4 days. The cells were then transferred to gelatin-coated dishes for the EBs to attach and spread on the tissue culture plates, in the course of which a series of cell growth factors such as basic fibroblast growth factor (bFGF), insulin-like growth factor 1 (IGF-1) and nicotinamide were added into the culture medium at specific time points to induce directed differentiation of the stem cells into PICC. Immunocytochemistry was employed to detect the cells positive for insulin and glucagon, which were observed with AFM. RESULTS: The embryonic stem cells developed into cell clusters of different sizes, in which the cells were tightly arranged. Islet B cells were numerous in the center of clusters and darkly stained, but fewer in the peripherals with lighter stains. Islet A cells expressing glucagon were relatively fewer in the cell clusters, found mainly in the peripherals. Scanning of the insulin-positive clusters by AFM revealed large quantity of tissue fibers resembling nerve fibers that formed a reticular structure in disorderly arrangement. Numerous round granules were observed in the cytoplasm of almost identical sizes ranging from 0.5 to 1.0 mum in diameter. CONCLUSION: The cell clusters obtained by directed differentiation are mature in both morphology and function with also well organized structures.

Animals↗
PubMed2005

Differentiation of hepatocytes from mouse embryonic stem cells and its significance.

BACKGROUND: There have been lots of important discoveries in the research on embryonic stem (ES) cells; but few studies have been involving in the differentiation and differentiation ratio of hepatic stem cells. To provide a new source of hepatocytes in hepatocytes transplantation and liver tissue engineering, we investigated the differentiation and differentiation ratio of hepatocytes in the ES cells differentiating system in a certain length of time. METHODS: BALB/c ES cells from mice were cultured for differentiation in medium without leukemia inhibitory factor (LIF). During the period of differentiation of ES cells, dual immunofluorescence was performed to analyze the expression of hepatic proteins in cytoplasm such as alpha-fetoprotein (AFP) and albumin (ALB). The count of relative hepatocyte-like cells was analyzed by flow cytometry (FCM) and the hepatic differentiation ratio was obtained. RESULTS: The expression of AFP was first determined at day 7 and that of ALB at day 13. The expressions of AFP and ALB became stronger with the extention of the differentiation time. The hepatic differentiation ratio at day 13 and 21 was 5.5% and 10.4%, respectively. CONCLUSION: ES cells could differentiate into hepatocytes, which should be a new source of hepatocytes in transplantation of hepatocytes and liver engineering.

Animals↗
PubMed2004

High-ratio differentiation of embryonic stem cells into hepatocytes in vitro.

BACKGROUND/PURPOSE: To date, in differentiating system of embryonic stem (ES) cells into hepatocytes, hepatic differentiation ratio was still not shown. Here, after investigating hepatic differentiation from ES cells, we determined the differentiation ratios of hepatocytes and studied how to improve the ratios in ES cell differentiating system. METHODS: Embryonic bodies (EBs) formed from ES cells for 5 days were plated onto culture dishes and some growth factors were added into medium for hepatic differentiation. Expressions of hepatic genes and proteins were analysed using reverse transcriptase-polymerase chain reaction, immunocytochemistry (ICC) and radioimmunoassay. The relative counts of hepatocyte-like cells among all EBs cells were analysed by flow cytometry by which hepatic differentiation ratios were determined. Then, we observed the spatial distribution of ICC-positive cells in EB cells cluster and isolated the cells of positive areas in other EBs clusters without ICC examined. At last, isolated cells were re-cultured with previous condition and hepatic differentiation ratios were also determined. RESULTS: The hepatic genes and proteins were, respectively, expressed in cytoplasm. Hepatic differentiation ratio was first determined at day 11 to be 12.1% and the level reached maximum to be 33.4% at day 21. In isolated cells culture system, hepatic genes and proteins expressed stronger than that expressed in EBs cluster and hepatic differentiation ratio was got to 72.6% at day 21. CONCLUSIONS: Isolating hepatocyte-like cells from EBs cell cluster and re-culturing them could produce hepatocytes with high differentiation ratio. This culture system may produce a new source of cell types for hepatocytes replacement therapies in hepatic failure.

Albumins↗
PubMed2004

[The ultrastructure study of membrane surface of the bone marrow CD34+ cells with the atomic force microscope].

Human CD34(+) hematopoietic cells, a distinctive cell population containing hematopoietic stem/progenitor cells (HSPC), have the capability to highly self-renewal, differentiation into all lineages of committed progenitor cells and reconstitution of both long-term hematopoiesis and immunefunctions after transplantation. CD34(+) hematopoietic cells from bone marrow (BM) recently have been employed for treating neoplastic and genetic disorders. This study was aimed to investigate membrane surface ultrastructures of bone marrow CD34(+) cell from mormal persons and leukemia patients and to compare their morphologic differences by using atomic force microscope (AFM). BM was collected from 5 normal donors and 6 leukaemia patients. All samples were layered on Ficoll-Paque gradients (specific gravity 1.077 g/ml) to separate the mononuclear cells. After that CD34(+) cells were purified by immuno-magnetic bead separation and evaluated with a FACS Calibur, these cells were detected by AFM of tapping mode inair. At lest 20 cells per samples were observed. The results showed that most of CD34(+) hematopoietic cells were like circle plate, the diameter was 10 - 14 microm. The surface of CD34(+) hematopoietic cell membrane was comparatively complex. The surface of CD34(+) hematopoietic cell membrane appeared as granular, with packed particles. With the region analysis function of IP2.1 software, the region of 2 microm x 2 microm was selected and four parameters of the surface (maximum peak-to-valley distance, average roughness, root-mean-squared roughness and mean height) were measured. Values of the 4 parameters showed that the characteristic parameters of CD34(+) HSPC from leukaemia were higher than that from normal person. It is concluded that AFM has specific advantages in analyzing cell membrane in the nanometer level and can gain more information. With the help of analysis software, AFM can be a helpful tool for fast leukaemic diagnosis and CD34(+) hematopoietic cells selection.

Antigens, CD34↗
PubMed2003

[Morphological observation on fibronectin fibrils surrounding human breast carcinoma cells by atomic force microscopy].

This report aimed at investigation on the application of atomic force microscope (AFM) in research on interaction between cells and extracellular matrix, and function of extracellular matrix. Distribution and array of fibronectin fibrils surrounding human breast carcinoma MCF-7-R cells were observed by atomic force microscope, and comparison of AFM with other traditional techniques was performed. Whole and local AFM morphological images of several human breast carcinoma MCF-7-R cells and fibronectin fibrils around cells were obtained by AFM. Distribution and array of fibronectin fibrils were found to be very regular, and the regulated array coordinated with functions of fibronectin fibrils very well. Owing to advantages of simple sample preparation and very high resolution, AFM is an ideal tool to in situ observation of extracellular matrix.

Breast Neoplasms↗