Epithelial Progenitor Cell Markers Research Articles

Three Dimensional Culture of Potential Epithelial Progenitor Cells in Human Lacrimal Gland.

PurposeWe investigate human lacrimal gland tissue to determine the presence of progenitor cells in this adult human tissue.MethodsSix human lacrimal gland tissues from donors were collected and stored immediately in the culture medium at 4°C until the next procedure. One part of the lacrimal gland tissue was prepared for immunofluorescence staining and the other part was prepared for primary cell culture. Immunofluorescence analysis was conducted to evaluate cultured lacrimal epithelial phenotype and progenitor cell markers for five passages. Real-time polymerase chain reaction (PCR) was performed to assess proliferation markers in the different passages. Three-dimensional culture and PCR were conducted to determine the differentiation potential of cultured human lacrimal gland cells.ResultsHuman lacrimal gland tissue expressed a number of epithelial progenitor cell markers. Precursor cell markers C-Kit, K15, Nestin, and P63 were observed in lacrimal gland tissues. Lacrimal gland epithelial cells were cultured successfully and passaged to P5. The cultured lacrimal gland epithelial cells were positive for pan-cytokeratin (PCK), AQP5, Rab3D, ABCB5, C-kit, K15, Ki67, and P63. Human lacrimal gland cells could form spheroids in vitro and then grow into mini-gland-like structures. PCR results showed proliferation and differentiation capability of those cultured cells.ConclusionsHuman lacrimal gland tissues contain precursor marker-positive cells and marker expression also was detected in ex vivo cultured cells, which showed differentiation capability.Translational RelevanceFuture studies of differentiation in human lacrimal gland tissue may aid in developing stem cell-based therapies for dry eye disease.

A new method for constructing engineered corneal epithelium based on embryonic stem cells

Objective To construct engineered corneal epithelium from embryonic stem cells (ESCs) using Rock inhibitor combined with hypoxia-normoxia culture condition. Methods Human ESC line H1 was induced to differentiate into epithelial-like cells by addition of retinoic acid (RA) and bone morphogenetic protein 4(BMP4) in the differentiation medium under the adherent culture condition.The ESCs derived epithelial-like cells were expanded in the mixed medium of SHEM and KSFM with the mixture ratio of 1∶2 with or without Rock inhibitor Y27632.The H1 derived epithelial-like cells were seeded on the denuded ammonic membrane to construct engineered corneal epithelium under hypoxia, normoxia and hypoxia-normoxia culture conditions, respectively.The inducted effect of ESCs into epithelial-like cells, the expansion ability of the epithelial-like cells and the characteristics of the constructed engineered corneal epithelium were evaluated by morphological observation, real-time fluorescent quantitative polymerase chain reaction (RTFQ-PCR) and immunofluorescence technology. Results Compared with the control group, the relative expressions of ESCs marker Oct4 mRNA, Notch signaling pathway related factors Notch1 and Jagged1 mRNA, and Wnt signaling pathways related factors c-myc and Cyclin D1 mRNA were significantly reduced, and the relative expressions of cutaneous ectoderm markers p63 and K18 mRNA were significantly increased at day 8 after induction in the induced group, with significant differences between them (t =14.63, 20.15, 93.50, 11.60, 19.30, 18.44, 22.63; all at P 0.05). The ESCs derived epithelium and constructed under hypoxia-normoxia culture condition showed more obvious stratification and tighter cell arrangement in comparison with those cells cultured in consistent hypoxia culture condition or normoxia culture condition.Epithelial markers Pan-CK and K18 as well as epithelial progenitor cell markers p63 and K14 expressed in the whole cell layers of the ESCs derived epithelium constructed under hypoxia-normoxia culture condition. Conclusions The addition of Y27632 enhances the proliferation ability of H1 derived epithelial cells and actives Notch signaling pathway and inhibits Wnt signaling pathway.The culture and construction in the expansion medium with Y27632 under the hypoxia-normoxia culture condition can promote the stratification of H1 derived engineered corneal epithelium. Key words: Embryonic stem cells; Engineered corneal epithlium; Rock inhibitor; Hypoxia-normoxia culture

Visualization of global RNA synthesis in a human (mini-) organ in situ by click chemistry.

RNA synthesis can be detected by 5-ethynyl uridine (EU) incorporation and click chemistry. Despite identifying a fundamental functional process, this technique has yet to be widely applied to complex human tissue systems. By incorporating EU into human hair follicle (HF) organs cultured ex vivo, nascent RNA synthesis was detected in situ. EU differentially incorporated across the HF epithelium.Interestingly, RNA synthesis did not correlate with protein synthesis, proliferation or epithelial progenitor cell marker expression. By treating human HFs with the cytotoxic cell cycle inhibitor (R)-CR8, which inhibits transcriptional regulators CDK7 and CDK9, it was further shown that this technique can be used to sensitively detect changes in global RNA synthesis in situ. Together, this work delineates new insights into nascent RNA synthesis within a human (mini)- organ and describes a novel read-out parameter that will enrich future ex vivo human tissue research studies.

Development of a conjunctival tissue substitute on the basis of plastic compressed collagen.

Ocular surface disorders, such as pterygium, cicatricial pemphigoid and external disruptions, can cause severe inflammation, scarring, fornix shortening as well as ankyloblepharon. Current treatments do not resolve these conditions sufficiently. The aim of this study was to evaluate clinical applicability and suitability of plastic compressed collagen to serve as a substrate for the expansion of human conjunctival epithelial cells in order to develop an epithelialized conjunctival substitute for fornix reconstruction. Human conjunctival epithelial cells were expanded on plastic compressed collagen gels. Epithelial cell characteristics were evaluated by haematoxylin and eosin staining, electron microscopy and cytokeratin expression. The expression of putative epithelial progenitor cell markers p63α, ABCG2 and CK15 was assessed by immunostaining. The proliferative capacity and clonal growth of the cells was evaluated before (P0) and after expansion (P1) on the plastic compressed collagen gels by colony forming efficiency assay. The potential clinical applicability of this gel substitutes was evaluated by assessment of their biomechanical properties as well as their surgical handling. Human conjunctival epithelial cells cultured on plastic and plastic compressed collagen gels formed a confluent cell layer and expressed CK19. The cells showed expression of the putative epithelial progenitor cell markers p63α, ABCG2 and CK15 and sustained colony forming ability. The compressed collagen gels showed a high ultimate tensile strength and elasticity and the surgical handling of gels was comparable to amniotic membrane. An epithelialized conjunctival tissue construct on the basis of compressed collagen might therefore be a promising alternative bioartificial tissue substitute for conjunctival reconstruction. Copyright © 2015 John Wiley & Sons, Ltd.

Integrin α6β4 Identifies Human Distal Lung Epithelial Progenitor Cells with Potential as a Cell-Based Therapy for Cystic Fibrosis Lung Disease

To develop stem/progenitor cell-based therapy for cystic fibrosis (CF) lung disease, it is first necessary to identify markers of human lung epithelial progenitor/stem cells and to better understand the potential for differentiation into distinct lineages. Here we investigated integrin α6β4 as an epithelial progenitor cell marker in the human distal lung. We identified a subpopulation of α6β4+ cells that localized in distal small airways and alveolar walls and were devoid of pro-surfactant protein C expression. The α6β4+ epithelial cells demonstrated key properties of stem cells ex vivo as compared to α6β4- epithelial cells, including higher colony forming efficiency, expression of stem cell-specific transcription factor Nanog, and the potential to differentiate into multiple distinct lineages including basal and Clara cells. Co-culture of α6β4+ epithelial cells with endothelial cells enhanced proliferation. We identified a subset of adeno-associated virus (AAVs) serotypes, AAV2 and AAV8, capable of transducing α6β4+ cells. In addition, reconstitution of bronchi epithelial cells from CF patients with only 5% normal α6β4+ epithelial cells significantly rescued defects in Cl- transport. Therefore, targeting the α6β4+ epithelial population via either gene delivery or progenitor cell-based reconstitution represents a potential new strategy to treat CF lung disease.

Transcription Factors Runx1 to 3 Are Expressed in the Lacrimal Gland Epithelium and Are Involved in Regulation of Gland Morphogenesis and Regeneration

Lacrimal gland (LG) morphogenesis and repair are regulated by a complex interplay of intrinsic factors (e.g., transcription factors) and extrinsic signals (e.g., soluble growth/signaling factors). Many of these interconnections remain poorly characterized. Runt-related (Runx) factors belong to a small family of heterodimeric transcription factors known to regulate lineage-specific proliferation and differentiation of stem cells. The purpose of this study was to define the expression pattern and the role of Runx proteins in LG development and regeneration. Expression of epithelial-restricted transcription factors in murine LG was examined using immunostaining, qRT-PCR, and RT(2)Profiler PCR microarrays. The role of Runx transcription factors in LG morphogenesis was studied using siRNA and ex vivo LG cultures. Expression of Runx transcription factors during LG regeneration was assessed using in vivo model of LG regeneration. We found that Runx factors are expressed in the epithelial compartment of the LG; in particular, Runx1 was restricted to the epithelium with highest level of expression in ductal and centroacinar cells. Downregulation of Runx1 to 3 expression using Runx-specific siRNAs abolished LG growth and branching and our data suggest that Runx1, 2, and 3 are partially redundant in LG development. In siRNA-treated LG, reduction of branching correlated with reduction of epithelial proliferation, as well as expression of cyclin D1 and the putative epithelial progenitor cell marker cytokeratin-5. Runx1, Runx3, and cytokeratin-5 expression increased significantly in regenerating LG and there was modest increase in Runx2 expression during LG differentiation. Runx1 and 2 are new markers of the LG epithelial lineage and Runx factors are important for normal LG morphogenesis and regeneration.

Quantitative single cell analysis of cell population dynamics during submandibular salivary gland development and differentiation

SummaryEpithelial organ morphogenesis involves reciprocal interactions between epithelial and mesenchymal cell types to balance progenitor cell retention and expansion with cell differentiation for evolution of tissue architecture. Underlying submandibular salivary gland branching morphogenesis is the regulated proliferation and differentiation of perhaps several progenitor cell populations, which have not been characterized throughout development, and yet are critical for understanding organ development, regeneration, and disease. Here we applied a serial multiplexed fluorescent immunohistochemistry technology to map the progressive refinement of the epithelial and mesenchymal cell populations throughout development from embryonic day 14 through postnatal day 20. Using computational single cell analysis methods, we simultaneously mapped the evolving temporal and spatial location of epithelial cells expressing subsets of differentiation and progenitor markers throughout salivary gland development. We mapped epithelial cell differentiation markers, including aquaporin 5, PSP, SABPA, and mucin 10 (acinar cells); cytokeratin 7 (ductal cells); and smooth muscle α-actin (myoepithelial cells) and epithelial progenitor cell markers, cytokeratin 5 and c-kit. We used pairwise correlation and visual mapping of the cells in multiplexed images to quantify the number of single- and double-positive cells expressing these differentiation and progenitor markers at each developmental stage. We identified smooth muscle α-actin as a putative early myoepithelial progenitor marker that is expressed in cytokeratin 5-negative cells. Additionally, our results reveal dynamic expansion and redistributions of c-kit- and K5-positive progenitor cell populations throughout development and in postnatal glands. The data suggest that there are temporally and spatially discreet progenitor populations that contribute to salivary gland development and homeostasis.

Effect of hypoxia on the proliferation of murine cornea limbal epithelial progenitor cells in vitro.

To investigate the effect of hypoxia on the proliferation of mouse corneal epithelial cells in vitro. Mouse corneal epithelial cells(MCEs) were cultured in normoxia (210mL/L O(2) and 50mL/L CO(2)) and hypoxia (20mL/L O(2) and 50mL/L CO(2)), respectively. Colony forming efficiency (CFE) and cell proliferation were determined. The expression of corneal epithelial progenitor cell marker p63 and K19 was investigated by immunostaining. Normoxic colonies were smaller compared with colonies formed in hypoxia. CFE was (12.50±1.50)% in hypoxic cultures, which was similar compared with normoxia cultures [(11.13±1.86)%, P>0.05)]. Cell proliferation was enhanced in hypoxia. Progenitor markers p63 and K19 were expressed in most cells under both normoxic and hypoxic conditions. Murine limbal epithelial progenitor cells can be efficiently expanded in hypoxic conditions.

ΔNp63 transcriptionally regulates ATM to control p53 Serine-15 phosphorylation

BackgroundΔNp63α is an epithelial progenitor cell marker that maintains epidermal stem cell self-renewal capacity. Previous studies revealed that UV-damage induced p53 phosphorylation is confined to ΔNp63α-positive cells in the basal layer of human epithelium.ResultsWe now report that phosphorylation of the p53 tumour suppressor is positively regulated by ΔNp63α in immortalised human keratinocytes. ΔNp63α depletion by RNAi reduces steady-state ATM mRNA and protein levels, and attenuates p53 Serine-15 phosphorylation. Conversely, ectopic expression of ΔNp63α in p63-null tumour cells stimulates ATM transcription and p53 Serine-15 phosphorylation. We show that ATM is a direct ΔNp63α transcriptional target and that the ΔNp63α response element localizes to the ATM promoter CCAAT sequence. Structure-function analysis revealed that the ΔNp63-specific TA2 transactivation domain mediates ATM transcription in coordination with the DNA binding and SAM domains.ConclusionsGermline p63 point mutations are associated with a range of ectodermal developmental disorders, and targeted p63 deletion in the skin causes premature ageing. The ΔNp63α-ATM-p53 damage-response pathway may therefore function in epithelial development, carcinogenesis and the ageing processes.

The cell-surface marker MTS24 identifies a novel population of follicular keratinocytes with characteristics of progenitor cells

We describe a novel murine progenitor cell population localised to a previously uncharacterised region between sebaceous glands and the hair follicle bulge, defined by its reactivity to the thymic epithelial progenitor cell marker MTS24. MTS24 labels a membrane-bound antigen present during the early stages of hair follicle development and in adult mice. MTS24 co-localises with expression of alpha6-integrin and keratin 14, indicating that these cells include basal keratinocytes. This novel population does not express the bulge-specific stem cell markers CD34 or keratin 15, and is infrequently BrdU label retaining. MTS24-positive and -negative keratinocyte populations were isolated by flow cytometry and assessed for colony-forming efficiency. MTS24-positive keratinocytes exhibited a two-fold increase in colony formation and colony size compared to MTS24-negative basal keratinocytes. In addition, both the MTS24-positive and CD34-positive subpopulations were capable of producing secondary colonies after serial passage of individual cell clones. Finally, gene expression profiles of MTS24 and CD34 subpopulations were compared. These results showed that the overall gene expression profile of MTS24-positive cells resembles the pattern previously reported in bulge stem cells. Taken together, these data suggest that the cell-surface marker MTS24 identifies a new reservoir of hair follicle keratinocytes with a proliferative capacity and gene expression profile suggestive of progenitor or stem cells.