Hyaline cartilage formation and enchondral ossification modeled with KUM5 and OP9 chondroblasts

Mesenchymal lineage cells and their importance in B lymphocyte niches

Early B lymphopoiesis occurs in the bone marrow and is reliant on interactions with numerous cell types in the bone marrow microenvironment, particularly those of the mesenchymal lineage. Each cellular niche that supports the distinct stages of B lymphopoiesis is unique. Different cell types and signaling molecules are important for the progressive stages of B lymphocyte differentiation. Cells expressing CXCL12 and IL-7 have long been recognized as having essential roles in facilitating progression through stages of B lymphopoiesis. Recently, a number of other factors that extrinsically mediate B lymphopoiesis (positively or negatively) have been identified. In addition, the use of transgenic mouse models to delete specific genes in mesenchymal lineage cells has further contributed to our understanding of how B lymphopoiesis is regulated in the bone marrow. This review will cover the current understanding of B lymphocyte niches in the bone marrow and key extrinsic molecules and signaling pathways involved in these niches, with a focus on how mesenchymal lineage cells regulate B lymphopoiesis.

Efficiency of Human Epiphyseal Chondrocytes with Differential Replication Numbers for Cellular Therapy Products

The cell-based therapy for cartilage or bone requires a large number of cells; serial passages of chondrocytes are, therefore, needed. However, fates of expanded chondrocytes from extra fingers remain unclarified. The chondrocytes from human epiphyses morphologically changed from small polygonal cells to bipolar elongated spindle cells and to large polygonal cells with degeneration at early passages. Gene of type II collagen was expressed in the cells only at a primary culture (Passage 0) and Passage 1 (P1) cells. The nodules by implantation of P0 to P8 cells were composed of cartilage and perichondrium. The cartilage consisted of chondrocytes with round nuclei and type II collagen-positive matrix, and the perichondrium consisted of spindle cells with type I collage-positive matrix. The cartilage and perichondrium developed to bone with marrow cavity through enchondral ossification. Chondrogenesis and osteogenesis by epiphyseal chondrocytes depended on replication number in culture. It is noteworthy to take population doubling level in correlation with pharmaceutical efficacy into consideration when we use chondrocytes for cell-based therapies.

Design and validation of a biomechanical bioreactor for cartilage tissue culture

Specific tissues, such as cartilage, undergo mechanical solicitation under their normal performance in human body. In this sense, it seems necessary that proper tissue engineering strategies of these tissues should incorporate mechanical solicitations during cell culture, in order to properly evaluate the influence of the mechanical stimulus. This work reports on a user-friendly bioreactor suitable for applying controlled mechanical stimulation--amplitude and frequency--to three-dimensional scaffolds. Its design and main components are described, as well as its operation characteristics. The modular design allows easy cleaning and operating under laminar hood. Different protocols for the sterilization of the hermetic enclosure are tested and ensure lack of observable contaminations, complying with the requirements to be used for cell culture. The cell viability study was performed with KUM5 cells.

Endochondral ossification model system: designed cell fate of human epiphyseal chondrocytes during long-term implantation

The aim of this study is to establish a recapitulation system of human endochondral ossification as a paradigm of developmental engineering. Chondrocytes were isolated from the epiphyseal cartilage of the supernumerary digits of infants with polydactyly. In vivo studies showed that implanted chondrocytes exhibited cartilaginous regeneration over a short period of time and subsequent endochondral ossification with a marrow cavity. Tracing studies revealed that cells of donor origin at the periphery of the cartilage migrated into the center of the cartilage and transformed into osteoblasts, adipocytes, and endothelial cells. Bone marrow was formed through anastomosis with the recipient endothelial system at 13 weeks, and from the migration of recipient hematopoietic cells at 50 weeks. This study provides a human endochondral ossification model system with transdifferentiation of the donor cells at the periphery of the cartilage. J. Cell. Physiol. 230: 1376-1388, 2015. © 2015 Wiley Periodicals, Inc., A Wiley Company.

Chondrogenic differentiation of immortalized human mesenchymal stem cells on zirconia microwell substrata

Human mesenchymal stem cells (hMSCs) that can differentiate into chondrocytes are a potential autologous cell source for repair of damaged tissue. Current methods usually induce the formation of all three chondrocyte phenotypes, hyaline, fibrous, and elastic, without the ability to selectively induce only one of them. By controlling the size of hMSC cell clusters, it may be possible to direct differentiation more uniformly toward hyaline chondrocytes. We designed new cell culture platforms containing microwells of different diameters. The platforms and wells were composed of a zirconia ceramics substratum. hMSCs briefly adhered to the substratum before releasing and entering the microwells. The physical restraints imposed by the microwells enabled hMSC clusters to homogenously differentiate into hyaline chondrocyte-like cells. Chondrogenic aggregates in microwells expressed the hyaline chondrocyte-specific genes Col II, aggrecan (ACAN), and cartilage oligomeric protein (COMP). The cultures also produced hyaline chondrocyte-specific matrix proteins Col II and ACAN homogenously throughout the aggregates. In contrast, chondrogenesis in pellet cultures was heterogeneous with the expression of nonhyaline chondrocyte genes CD105, Col X, and Col I. In these pellet cultures, hyaline and nonhyaline chondrocyte-specific matrix proteins were distributed heterogeneously. Thus, this novel ceramic microwell substratum technology efficiently directed the differentiation of hyaline chondrocyte-like cells from hMSCs. These results indicate that there is a close relationship between hMSC cluster size regulation in the microwells and differentiation tendency. This microwell culture differentiation method will provide a valuable experimental system for both experimental and potential clinical studies.

Effects of adipose-derived mesenchymal cells on ischemia-reperfusion injury in kidney

BACKGROUND

Acute kidney injury (AKI) is a critical condition for kidney and other remote organs, including the lung. However, available treatments for AKI are limited. In this study, we explored the effect of adipose-derived mesenchymal cells on a mouse model of AKI.

METHODS

Adipose-derived mesenchymal cells were isolated from mouse subcutaneous and peritoneal adipose tissue by digestion with collagenase type I. The left renal artery and vein of C57BL/6 mice were clamped for 45 min to induce ischemia and were injected with the adipose-derived mesenchymal cells [1 × 10(5) cells/0.2 ml phosphate-buffered saline (PBS)] or 0.2 ml PBS via the tail vein on days 0, 1, and 2.

RESULTS

The adipose-derived mesenchymal cells had stem-cell surface markers and multilineage differentiating potentials. Administered adipose-derived mesenchymal cells homed primarily into lung. Interestingly, repeated administration of adipose-derived mesenchymal cells reduced acute tubular necrosis and interstitial macrophage infiltration in the injured kidney, accompanied with reduced cytokine and chemokine expression.

CONCLUSION

Adipose-derived mesenchymal cells can be used as cell-based therapy for ischemic kidney injury.

Identification of multipotent stem/progenitor cells in murine sclera

PURPOSE

The sclera forms the fibrous outer coat of the eyeball and acts as a supportive framework. The purpose of this study was to examine whether the sclera contains mesenchymal stem/progenitor cells.

METHOD

Scleral tissue from C57BL6/J mice was separated from the retina and choroid and subsequently enzyme digested to release single cells. Proliferation capacity, self-renewal capacity, and ability for multipotent differentiation were analyzed by BrdU labeling, flow cytometry, reverse transcriptase-polymerase chain reaction, immunocytochemistry, and in vivo transplantation.

RESULTS

The scleral stem/progenitor cells (SSPCs) possessed clonogenic and high doubling capacities. These cells were positive for the mesenchymal markers Sca-1, CD90.2, CD44, CD105, and CD73 and negative for the hematopoietic markers CD45, CD11b, Flk1, CD34, and CD117. In addition to expressing stem cell genes ABCG2, Six2, Notch1, and Pax6, SSPCs were able to differentiate to adipogenic, chondrogenic, and neurogenic lineages.

CONCLUSIONS

This study indicates that the sclera contains multipotent mesenchymal stem cells. Further study of SSPCs may help elucidate the cellular and molecular mechanism of scleral diseases such as scleritis and myopia.

Lectin microarray analysis of pluripotent and multipotent stem cells

Stem cells have a capability to self-renew and differentiate into multiple types of cells; specific markers are available to identify particular stem cells for developmental biology research. In this study, we aimed to define the status of somatic stem cells and the pluripotency of human embryonic stem (hES) and induced pluripotent stem (iPS) cells using a novel molecular methodology, lectin microarray analysis. Our lectin microarray analysis successfully categorized murine somatic stem cells into the appropriate groups of differentiation potency. We then classified hES and iPS cells by the same approach. Undifferentiated hES cells were clearly distinguished from differentiated hES cells after embryoid formation. The pair-wise comparison means based on 'false discovery rate' revealed that three lectins -Euonymus europaeus lectin (EEL), Maackia amurensis lectin (MAL) and Phaseolus vulgaris leucoagglutinin [PHA(L)]- generated maximal values to define undifferentiated and differentiated hES cells. Furthermore, to define a pluripotent stem cell state, we generated a discriminant for the undifferentiated state with pluripotency. The discriminant function based on lectin reactivities was highly accurate for judgment of stem cell pluripotency. These results suggest that glycomic analysis of stem cells leads to a novel comprehensive approach for quality control in cell-based therapy and regenerative medicine.

Molecular mechanisms of cartilage remodelling in osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease that is characterized primarily by progressive breakdown of articular cartilage. The loss of proteoglycans, the mineralization of the extracellular matrix (ECM) and the hypertrophic differentiation of the chondrocytes constitute hallmarks of the disease. The pathogenesis of OA includes several pathways, which in single are very well investigated and partly understood, but in their complex interplay remain mainly unclear. This review summarises recent data on the underlying mechanisms, specifically with respect to cell-matrix interactions and cartilage mineralization. It points out why these findings are of importance for future OA research and for the development of novel therapeutic strategies to treat OA.

Identification of five developmental processes during chondrogenic differentiation of embryonic stem cells

BACKGROUND

Chondrogenesis is the complex process that leads to the establishment of cartilage and bone formation. Due to their ability to differentiate in vitro and mimic development, embryonic stem cells (ESCs) show great potential for investigating developmental processes. In this study, we used chondrogenic differentiation of ESCs as a model to analyze morphogenetic events during chondrogenesis.

METHODOLOGY/PRINCIPAL FINDINGS

ESCs were differentiated into the chondrocyte lineage, forming small cartilaginous aggregates in suspension. Differentiated ESCs showed that chondrogenesis was typically characterized by five overlapping stages. During the first stage, cell condensation and aggregate formation was observed. The second stage was characterized by differentiation into chondrocytes and fibril scaffold formation within spherical aggregates. Deposition of cartilaginous extracellular matrix and cartilage formation were hallmarks of the third stage. Apoptosis of chondrocytes, hypertrophy and/or degradation of cartilage occurred during the fourth stage. Finally, during the fifth stage, bone replacement with membranous calcified tissues took place.

CONCLUSIONS/SIGNIFICANCE

We demonstrate that ESCs show the chondrogenic differentiation pathway from the pluripotent stem cell to terminal skeletogenesis through these five stages in vitro. During each stage, morphological changes acquired in preceding stages played an important role in further development as a scaffold or template in subsequent stages. The study of chondrogenesis via ESC differentiation may be informative to our further understanding of skeletal growth and regeneration.

Human sclera maintains common characteristics with cartilage throughout evolution

BACKGROUND

The sclera maintains and protects the eye ball, which receives visual inputs. Although the sclera does not contribute significantly to visual perception, scleral diseases such as refractory scleritis, scleral perforation and pathological myopia are considered incurable or difficult to cure. The aim of this study is to identify characteristics of the human sclera as one of the connective tissues derived from the neural crest and mesoderm.

METHODOLOGY/PRINCIPAL FINDINGS

We have demonstrated microarray data of cultured human infant scleral cells. Hierarchical clustering was performed to group scleral cells and other mesenchymal cells into subcategories. Hierarchical clustering analysis showed similarity between scleral cells and auricular cartilage-derived cells. Cultured micromasses of scleral cells exposed to TGF-betas and BMP2 produced an abundant matrix. The expression of cartilage-associated genes, such as Indian hedge hog, type X collagen, and MMP13, was up-regulated within 3 weeks in vitro. These results suggest that human 'sclera'-derived cells can be considered chondrocytes when cultured ex vivo.

CONCLUSIONS/SIGNIFICANCE

Our present study shows a chondrogenic potential of human sclera. Interestingly, the sclera of certain vertebrates, such as birds and fish, is composed of hyaline cartilage. Although the human sclera is not a cartilaginous tissue, the human sclera maintains chondrogenic potential throughout evolution. In addition, our findings directly explain an enigma that the sclera and the joint cartilage are common targets of inflammatory cells in rheumatic arthritis. The present global gene expression database will contribute to the clarification of the pathogenesis of developmental diseases such as high myopia.

Gremlin enhances the determined path to cardiomyogenesis

Background

The critical event in heart formation is commitment of mesodermal cells to a cardiomyogenic fate, and cardiac fate determination is regulated by a series of cytokines. Bone morphogenetic proteins (BMPs) and fibroblast growth factors have been shown to be involved in this process, however additional factors needs to be identified for the fate determination, especially at the early stage of cardiomyogenic development.

Methodology/Principal Findings

Global gene expression analysis using a series of human cells with a cardiomyogenic potential suggested Gremlin (Grem1) is a candidate gene responsible for in vitro cardiomyogenic differentiation. Grem1, a known BMP antagonist, enhanced DMSO-induced cardiomyogenesis of P19CL6 embryonal carcinoma cells (CL6 cells) 10–35 fold in an area of beating differentiated cardiomyocytes. The Grem1 action was most effective at the early differentiation stage when CL6 cells were destined to cardiomyogenesis, and was mediated through inhibition of BMP2. Furthermore, BMP2 inhibited Wnt/β-catenin signaling that promoted CL6 cardiomyogenesis.

Conclusions/Significance

Grem1 enhances the determined path to cardiomyogenesis in a stage-specific manner, and inhibition of the BMP signaling pathway is involved in initial determination of Grem1-promoted cardiomyogenesis. Our results shed new light on renewal of the cardiovascular system using Grem1 in human.

Guided differentiation of embryonic stem cells into Pdx1-expressing regional-specific definitive endoderm

The generation of specific lineages of the definitive endoderm from embryonic stem (ES) cells is an important issue in developmental biology, as well as in regenerative medicine. This study demonstrates that ES cells are induced sequentially into regional-specific gut endoderm lineages, such as pancreatic, hepatic, and other cell lineages, when they are cultured directly on a monolayer of mesoderm-derived supporting cells. A detailed chronological analysis revealed that Activin, fibroblast growth factor, or bone morphogenetic protein signals are critical at various steps and that additional short-range signals are required for differentiation into Pdx1-expressing cells. Under selective culture conditions, definitive endoderm (47%) or Pdx1-positive pancreatic progenitors (30%) are yielded at a high efficiency. When transplanted under the kidney capsule, the Pdx1-positive cells further differentiated into all three pancreatic lineages, namely endocrine, exocrine, and duct cells.