Immunocyto- and histochemical profiling of nucleostemin expression: Marker of epidermal stem cells?

RNA-seq reveal RNA binding protein GNL3 as a key mediator in the development of psoriasis vulgaris by regulating the IL23/IL17 axis

BACKGROUND

Psoriasis is a systemic chronic inflammatory skin disorder that was prone to recurrence. The RNA binding protein GNL3 has an important function in maintaining the proliferative ability of stem cells, and its overexpression leads to apoptosis. GNL3 is expressed in the epidermis, however, its regulatory mechanism in psoriasis vulgaris is still poorly understood.

OBJECTIVE

To identify the role of GNL3 in the pathogenesis of psoriasis vulgaris.

MATERIALS AND METHODS

RNA-seq was performed to obtain the data of genes' expression and splicing events in Hela cells after shGNL3 and shCtrl was transferred. High quality results of differentially expressed genes (DEGs) and alternative splicing events (ASEs) were further attained by quality control and analysis. Through the functional enrichment analysis of DEGs and ASEs, the regulating effect of GNL3 was discussed, and the hypothesis was further confirmed in HaCat cells and psoriasis lesions.

RESULTS

The mRNA expression of IL23A in Hela cells was upregulated in GNL3 knockdown, and the ratio of ASE occurred in TNFAIP3 was increased. However, in HaCaT cells, the mRNA expression level of IL23A was downregulated in GNL3 knockdown, and the ratio of ASE of TNFAIP3 was decreased. Additionally, the results obtained in HaCaT cells was further validated in the lesional psoriatic skin.

CONCLUSION

GNL3 takes an important part in the development of psoriasis vulgaris by regulating the IL23/IL17 axis, which may serve as the basis of effective targeted treatment in future.

Using human epithelial amnion cells in human de-epidermized dermis for skin regeneration

BACKGROUND

Human amniotic epithelial cells (hAECs) is a desirable reserve of stem cells. Human de-epidermized dermis (DED) retains basic tissue structure and parts of the basement membrane (BM) components at the acelluIar dermal surface, and provides a potential tool for skin regeneration.

OBJECTIVE

To evaluate the potential role of hAECs in skin regeneration, we used DED to perform organotypic culture of hAECs to develop organotypic skin.

METHODS

HAECs were isolated and cultured. Biological characteristics of hAECs were determined by immunocytochemistry and flow cytometry. To prepare DED, the epidermis was removed and then repeated freeze-thaw cycles. HAECs and fibroblast were seeded onto DED to perform the submerged culture for 3 days and then to be maintained at the air-liquid interface for 14 days to form organotypic culture. To identify whether the obtained DED retain the BM structure and components, the histological characteristics of DED and the BM were detected by immunohistochemistry. To evaluate whether the organotypic skin has similar histological characteristics with normal human skin, the marks of epidermal proliferation and differentiation and basement membrane component were detected by immunohistochemistry. Moreover, cell ultrastructure, cell-cell contact and ultrastructure of BM were examined under the transmission electron microscopy.

RESULTS

HAECs has stem-cell characteristics with strong pluripotent Oct-4 and embryonic marker SSEA-4 expression. DED has effectively cleansed the cell components and continuous distributions of laminin and collagen IV. The histological appearance of tissue-engineered skin in vitro has 4 to 9 continuous layers of stratified epithelium and is similar to normal human skin in morphology. Immunohistochemical studies revealed that proliferation and differentiation markers such as Ki67, CK19, CK14, CK10, filaggrin but not CK18 expressed similar pattern characteristics to normal human epidermis. In addition, Periodic acid-Schiff stain showed that a uniform red staining strip located at the epidermal-dermal junction. BM component proteins (type IV collagen and laminin) and cell adhesion protein (desmoglein) were detected by immunohistochemistry in organotypic skin. Ultrastructurally, desmosomes, hemidesmosomes and BM zone (BMZ) were observed in organotypic skin.

CONCLUSIONS

Our studies indicate that the hAECs is a promising stem cell source for tissue-engineered skin, and DED with hAECs is a potential application prospects in regenerative medicine.

Immunohistochemical study of doublecortin and nucleostemin in canine brain

Finding a marker of neural stem cells remains a medical research priority. It was reported that the proteins doublecortin and nucleostemin were related with stem/progenitor cells in central nervous system. The aim of the present immunohistochemical study was to evaluate the expression of these proteins and their pattern of distribution in canine brain, including age-related changes, and in non-nervous tissues. We found that doublecortin had a more specific expression pattern, related with neurogenesis and neuronal migration, while nucleostemin was expressed in most cells of almost every tissue studied. The immunolabeling of both proteins decreased with age. We may conclude that nucleostemin is not a specific marker of stem/progenitor cells in the dog. Doublecortin, however, is not an exclusive marker of neural stem cells, but also of neuronal precursors.

Nucleostemin affects the proliferation but not differentiation of oral squamous cell carcinoma cells

Nucleostemin (NS) has been reported as essential for stem and cancer cell proliferation. To investigate the significance of NS in oral squamous cell carcinomas (OSCCs), we examined NS expression in neoplastic tissue of the tongue and in OSCC cell lines. Nucleostemin expression in the histological samples showed positive correlation with Ki-67 expression. Furthermore, NS expression was associated with cellular proliferation in OSCC cell lines using siRNA, which upregulated p27, a cyclin-dependent kinase inhibitor. Regarding OSCC differentiation, NS expression did not influence cornification or oral epithelial differentiation markers such as involucrin and cytokeratin19. Thus, NS is widely expressed in normal and neoplastic oral epithelial tissues, and is likely a marker of proliferation.

Head and neck squamous cancer stromal fibroblasts produce growth factors influencing phenotype of normal human keratinocytes

Epithelial-mesenchymal interaction between stromal fibroblasts and cancer cells influences the functional properties of tumor epithelium, including the tumor progression and spread. We compared fibroblasts prepared from stroma of squamous cell carcinoma and normal dermal fibroblasts concerning their biological activity toward normal keratinocytes assessed by immunocytochemistry and profiling of gene activation for growth factors/cytokines by microarray chip technology. IGF-2 and BMP-4 were determined as candidate factors responsible for tumor-associated fibroblast activity that influences normal epithelia. This effect was confirmed by addition of recombinant IGF-2 and BMP4, respectively, to the culture medium. This hypothesis was also verified by inhibition experiments where blocking antibodies were employed in the medium conditioned by cancer-associated fibroblast. Presence of these growth factors was also detected in tumor samples.

Myocardial induction of nucleostemin in response to postnatal growth and pathological challenge

Stem cell-specific proteins and regulatory pathways that determine self-renewal and differentiation have become of fundamental importance in understanding regenerative and reparative processes in the myocardium. One such regulatory protein, named nucleostemin, has been studied in the context of stem cells and several cancer cell lines, where expression is associated with proliferation and maintenance of a primitive cellular phenotype. We find nucleostemin is present in young myocardium and is also induced following cardiomyopathic injury. Nucleostemin expression in cardiomyocytes is induced by fibroblast growth factor-2 and accumulates in response to Pim-1 kinase activity. Cardiac stem cells also express nucleostemin that is diminished in response to commitment to a differentiated phenotype. Overexpression of nucleostemin in cultured cardiac stem cells increases proliferation while preserving telomere length, providing a mechanistic basis for potential actions of nucleostemin in promotion of cell survival and proliferation as seen in other cell types.

Knocking-down the expression of nucleostemin significantly decreases rate of proliferation of rat bone marrow stromal stem cells in an apparently p53-independent manner

OBJECTIVES

Nucleostemin (NS) is a recently identified GTP-binding protein, predominantly expressed in embryonic and adult stem cells but not in terminally differentiated cells. NS is expressed in bone marrow-derived mesenchymal stem cells, and its expression ceases upon induction of neural differentiation. The major aim of this study was to determine whether down-regulation of NS expression acts as a promoter, or otherwise as a by-product of differentiation and senescence processes.

MATERIALS AND METHODS

We used RNA interference protocols to specifically knock down NS in rat bone marrow-derived stromal stem cells. Changes in rate of proliferation and cell cycle profile after knocking-down of NS were measured. In addition, changes in expression of associated genes were studied by semiquantitative RT-PCR, Western blotting and immunocytochemistery.

RESULTS

Knocked-down expression of NS caused a significant decrease in the rate of cell proliferation with concomitant shutting off of expression of cyclin D1 and survivin, two other well-known regulators of cell proliferation. Interestingly, we noticed no obvious changes in expression level of p21, the main effector of p53 for its cell cycle repressing function.

CONCLUSION

Our findings revealed a master role for NS in promoting proliferation of rat bone marrow-derived stromal stem cells. Moreover, we suggest that despite previous proposals, the cell cycle arrest/inhibitory role of NS is unlikely to be related to its proposed property of interaction with p53.

Marker profiling of normal keratinocytes identifies the stroma from squamous cell carcinoma of the oral cavity as a modulatory microenvironment in co-culture

PURPOSE

The microenvironment established by stromal cells may or may not influence phenotypic aspects of epithelial cells and may be relevant for tumor and stem cell biology. We address this issue for keratinocytes using tumor-derived stromal cells in a co-culture system.

MATERIALS AND METHODS

We isolated stromal cells from human squamous cell carcinoma tissue and studied their effect on phenotypic characteristics of normal human interfollicular keratinocytes in vitro.

RESULTS

Stromal fibroblasts significantly influence immuno- and lectin cytochemical properties of co-cultured normal keratinocytes. Expression of keratins 8 and 19, the nucleolar protein nucleostemin, parameters related to adhesion/growth-regulatory galectins and the epithelial-mesenchymal transition were altered. This biological activity of tumor-derived stromal cells, which did not require cell contact, appeared to be stable, because it was maintained during passaging of keratinocytes in the absence of cancer cells.

CONCLUSIONS

Tumor-derived stromal fibroblasts acquire distinct properties to shape a microenvironment conducive to altering the phenotypic characteristics of normal epithelial cells in vitro.

Stromal fibroblasts from basal cell carcinoma affect phenotype of normal keratinocytes

BACKGROUND

Epithelial-mesenchymal interactions are important not only to direct the course of prenatal development of skin and its appendages but also to influence the behaviour of transformed epithelial cells.

OBJECTIVES

Evaluation of the role of stromal fibroblasts on the phenotype of epithelial cells of basal cell carcinoma (BCC).

METHODS

The phenotype of human BCC was compared with the in vitro model where the growth and phenotypic pattern of normal human keratinocytes were monitored in co-culture with fibroblasts prepared from stroma of BCC (BCCFs), with normal dermal fibroblasts or with two established fibroblast lines. We visualized the expression of a panel of keratins, three types of endogenous lectin [galectin (Gal)-1, Gal-3 and Gal-7], binding sites for Gal-1 and Gal-3, a proliferation marker Ki67, nucleolar protein nucleostemin (NuclS) and membrane protein Ber-EP4. A phenotype and karyotype of BCCFs were also monitored. BCCFs were also grafted to NOD/LtSz-Rag1(null) mice to evaluate their malignant potential.

RESULTS

Prolonged cultivation of BCCFs has led to morphological changes, loss of contact inhibition, loss of fibroblast surface antigens and progressive aneuploidity. However, a fully malignant phenotype did not develop as these cells did not form tumours in immunodeficient mice. Co-culture of BCCFs with normal keratinocytes in vitro led to their phenotypical changes resembling those in BCC, namely, expression of keratin 19. These keratinocytes also strongly express nuclear binding sites for Gal-1 and NuclS. This phenotype was not observed when normal keratinocytes were cultured with nontumour-originated fibroblasts.

CONCLUSIONS

These observations indicate that BCCFs may differ from normal fibroblasts and may play a regulatory role in BCC biology.