ABSTRACT
BACKGROUND:Hematopoietic microenvironment regulates hematopoietic stem cel s mainly through the cel-cel , cel-soluble regulator and cel-extracel uar matrix modes. OBJECTIVE:To review the molecular mechanism underlying regulation of hematopoietic stem cel s under the cel-cel , cel-soluble factors and cel-extracel ular matrix modes. METHODS:A computer-based online search of PubMed database was performed to search related articles with the key words of“Niche, HSC, VCAM-1, VLA-4, TPO, MPL, ECM, Integrin, N-cadherin, ANG-1, Tie2, VLA-5, Jagged-1, Notch, CXCL12, CXCR4, SCF, Kit, BMPs/TGF-β, TGF-βR, IFNα, IFNαR”in English. Irrelevant or repetitive studies as wel as old literature were excluded, and final y 80 articles were included in result analysis. RESULTS AND CONCLUSION:Cel s on the endosteal surface, vascular endothelial cel s, perivascular cel s, and some unknown or certain cel s or smal molecules in the bone marrow cavity constitute the specialized microenvironment for hematopoietic stem cel s. Hematopoietic stem cel s in the hematopoietic microenvironment remain a relatively steady state, which is the result of mutual contact of hematopoietic stem cel s and hematopoietic microenvironment under the regulation of some important molecules, such as Pten and osteopontin, via the pathway between cel-intercel ular adhesions, intercel ular soluble factors, and cel s and extracel ular matrix.
ABSTRACT
BACKGROUND:Bone marrow mesenchymal stem cel s from chickens are important cel models for embryonic developmental biology, immunology and oncology research. However, it is difficult to keep bone marrow mesenchymal stem cel s with good undifferentiated potential in a large-scale expansion system. OBJECTIVE:To establish a culture system in vitro with laminin coating to expand bone marrow mesenchymal stem cel s from chickens. METHODS:Isolated bone marrow mesenchymal stem cel s from chickens were seeded in laminin-coated plates and traditional two-dimensional plates, respectively. After expansion in vitro, the morphological characteristics, expression of surface markers, expansion characteristics and adipogenic differentiation of bone marrow mesenchymal stem cel s in both conditions were analyzed and compared. RESULTS AND CONCLUSION:There were no statistical differences in the morphological characteristics and expression of surface markers of bone marrow mesenchymal stem cel s expanded by laminin-coated plates and traditional two-dimensional plates. But, the expansion characteristics and adipogenic differentiation of bone marrow mesenchymal stem cel s cultured in laminin-coated plates were better than those in traditional two-dimensional plates. Laminin culture system could quickly amplify out of a large number of chicken bone marrow mesenchymal stem cel s with better proliferation ability and undifferentiated performance. Al above results indicated that a more efficient expansion system with laminin coating is established.
ABSTRACT
BACKGROUND:Rapid loss of liver-specific functions of the cultured hepatocytes limits the development of hepatocyte-based therapies. OBJECTIVE:To establish a three-dimensional culture system based on col agen hydrogel that enables to enhance liver-specific functions for a long period during culture of hepatocytes. METHODS:Hepatocytes were isolated from Sprague-Dawley rats and then encapsulated into liquid type Ⅰcol agen solution that was premixed with hepatocyte growth factor and Dulbecco's modified Eagle’s medium to create hepatocyte/col agen hydrogel compounds. The compounds were inoculated into a 96-wel plate. After gelation, culture medium was added. Light microscope, hematoxylin-eosin staining and transmission electron microscopy were used to examine the morphological characteristics and ultrastructure of the cultured hepatocytes. The cellsupernatant was col ected and tested for albumin secretion and urea synthesis. Periodic acid-schiff staining, immunofluorescence staining and quantitative real-time PCR were also used to further clarify liver-specific phenotype or function of the hepatocytes.RESULTS AND CONCLUSION:(1) Light microscope revealed that hepatocytes were round shape and distributed uniformly in col agen hydrogel. The three-dimensional hepatocyte culture system exhibited similarities to liver-like structure and tight junction were formed between hepatocytes after 14 days of culture. (2) Within the three-dimensional culture system, hepatocytes remained positive for periodic acid-schiff staining, albumin and hepatocyte nuclear factor-4αpositive after 14-day culture, which provided the convincing evidence of highly differentiated primary hepatocytes with functions of glycogen and albumin synthesis. (3) The albumin and urea productions in the three-dimensional culture system had a significantly higher level than in the two-dimensional culture, and could remain at a high level at least for 15 days. (4) The expression levels of hepatocyte-specific genes including Albumin, HNF-4α, Claudin-3, CYP1A1, CYP3A1 and G6P were significantly improved in the three-dimensional culture as compared with the two-dimensional culture. The col agen hydrogel based three-dimensional culture system provides a valuable model to enhance the hepatocyte functional maintenance and lay the foundation for the development of hepatocyte-based therapy for liver disease.