Stem Cells : Stem cells can be stem cells are able to reproduce themselves (Self-renewal) throughout the life-span of the animal, and they are able to give rise to differentiated cells (Multilineage Diffrentiation).

    Embryonic Stem Cells

    Adult Stem Cells

Differentiation Potential of Embryonic Stem (ES) Cells.

ICM : Inner Cell Mass of mammalian blastocysts.

ES : pluripotent Embryonic Stem cells.

       It needs the Oct4 and LIF for their pluripotent state

Embryoid bodies :

       When ES withdraw LIF, they differntiate and spawn many cell lineages.

The Existence of Adult Stem Cells and Their Niches

Adult Stem Cells : relatively slow-cycling cells able to respond to specific environmental signals and either generate new stem cells or select a particular differentiation program

When a stem cell undergoes a commitment to differentiate, it often first enters a transient state of rapid proliferation. Upon exhaustion of its proliferative potential, the transiently amplifying cell withdraws from its cycle and executes its terminal differentiation program

Stem Cells Self-Renew and Differentiate to Give Rise to Transit Amplifying and Fully Differentiated Cells

Stem Cells Develop and Maintain Their Ability to Self-Renew within a Specific Niche. Adult stem cells are often localized to specific niches, where they utilize many but not necessarily all, of the external and intrinsic cues used by their embryonic counterparts in selecting a specific fate.

Self-Renewing Epithelial Stem Cell Niches

Epidermis and Hair Follicles.

The hair follicle represents a major repository of keratinocyte stem cells in mouse skin, and that follicular bulge stem cells are potentially bipotent as they can give rise to not only the hair follicle, but also the epidermis.

Intestinal Epithelium.

Multipotent Neural Stem Cells in the Brain.

Hematopoietic Stem Cells.

The Unexplored Area :

1.  To characterize the epithelial stem cells in terms of molecular markers.

2. To establish more in vitro culture systems, like those used for epidermis , in which the control of stem cell behavior can be investigated in detail.

3. To identify the mysterious environmental factors that control stem cell behavior, both with regard to self-renewal  potential and to the ability to form particular types of differentiated cells.

To identify the stem cells molecule marker

Putative molecule, such as alpha-enolase, cytokeratin 15

Prepare the specific Monoclonal antibody that recognize the limbus cells (cornea stem cells)  

(1)   Use the limbus cells lysate for immunization and screening the specific monoclonal antibody (mAb).

(2)   The specific mAb is further characterized by immunostaining.

(3)   Screening the expression cDNA library with this specific mAb or identify the protein which is 

      immunoprecipitated with this specific mAb by LC/MS/MS .

To identify the expression patterns of cytokine within limbal epithelial cells cultured on amniotic membrane or corneal epithelial cultured on amniotic membrane. 

Which cytokines are involved between the epithelial cells and the amniotic membrane?  PDGF-B, b-FGF, EGF, IL-1, LIF, KGF, EGFR, TGF-b, TGFR……  Up or down regulate

1.  Different cell culture microenvironment:

    Limbal epithelial cells / amniotic membrane

     Corneal epithelial cells/ amniotic membrane

     Conjunctival epithelial cells / amniotic membrane

     Limbal epithelial cells / NIH 3T3 cells

     Corneal epithelial cells / NIH 3T3 cells

     Conjunctival epithelial cells / NIH 3T3 cells

2.  Compare the expression level of cytokines under different cell culture microenvironment

 RT-PCR

 Northern blot analysis

 ELISA

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