Characterization and distribution of hyaluronan and the proteoglycans decorin, biglycan and perlecan in the developing embryonic mouse gonad

Morphological damage in Sertoli, myoid and interstitial cells in a mouse model of mucopolysaccharidosis type I (MPS I)

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disease caused by a mutation in the IDUA gene, which codes α-L-iduronidase (IDUA), a lysosomal hydrolase that degrades two glycosaminoglycans (GAGs): heparan sulfate (HS) and dermatan sulfate (DS). GAGs are macromolecules found mainly in the extracellular matrix and have important signaling and structural roles which are essential to the maintenance of cell and tissue physiology. Nondegraded GAGs accumulate in various cell types, which characterizes MPS I as a multisystemic progressive disease. Many tissues and vital organs have been described in MPS I models, but there is a lack of studies focused on their effects on the reproductive tract. Our previous studies indicated lower sperm production and morphological damage in the epididymis and accessory glands in male MPS I mice, despite their ability to copulate and to impregnate females. Our aim was to improve the testicular characterization of the MPS I model, with a specific focus on ultrastructural observation of the different cell types that compose the seminiferous tubules and interstitium. We investigated the testicular morphology of 6-month-old male C57BL/6 wild-type (Idua+/+) and MPS I (Idua-/-) mice. We found vacuolated cells widely present in the interstitium and important signs of damage in myoid, Sertoli and Leydig cells. In the cytoplasmic region of Sertoli cells, we found an increased number of vesicles with substrates under digestion and a decreased number of electron-dense vesicles similar to lysosomes, suggesting an impaired flux of substrate degradation. Conclusions: Idua exerts an important role in the morphological maintenance of the seminiferous tubules and the testicular interstitium, which may influence the quality of spermatogenesis, having a greater effect with the progression of the disease.

Screening of Integrin Heterodimers Expressed Functionally on the Undifferentiated Spermatogonial Stem Cells in the Outbred ICR Mice

Background and Objectives

Outbred mice are widely used in toxicology, pharmacology, and fundamental biomedical research. However, there have been no reports of in vitro culture systems for spermatogonial stem cells (SSCs) derived from these mice.

Methods

As a step towards constructing a non-cellular niche supporting the in vitro maintenance of outbred mouse SSC self-renewal, we systematically investigated the types of integrin heterodimers that are expressed transcriptionally, translationally, and functionally in SSCs derived from Imprinting Control Region (ICR) mice.

Results

Among the genes encoding 25 integrin subunits, integrin α₁, α₅, α₆, α₉, α_V, and α_E, and integrin β₁ and β₅ had significantly higher transcriptional levels than the other subunits. Furthermore, at the translational level, integrin α₅, α₆, α₉, α_V, α_E, and β₁ were localized on the surface of SSCs, but integrin α₁ and β₅ not. Moreover, significantly stronger translational expression than integrin α₉ and α_E was observed in integrin α₅, α₆, α_V, and β₁. SSCs showed significantly increased adhesion to fibronectin, laminin, tenascin C and vitronectin, and functional blocking of integrin α₅β₁, α₆β₁, α₉β₁ or α_Vβ₁ significantly inhibited adhesion to these molecules.

Conclusions

We confirmed that integrin α₅β₁, α₆β₁, α₉β₁ and α_Vβ₁ actively function on the surface of undifferentiated SSCs derived from outbred ICR mice.

Characterization, recellularization, and transplantation of rat decellularized testis scaffold with bone marrow-derived mesenchymal stem cells

BACKGROUND

Regenerative medicine potentially offers the opportunity for curing male infertility. Native extracellular matrix (ECM) creates a reconstruction platform to replace the organs. In this study, we aimed to evaluate the efficiency of the testis decellularized scaffold as a proper niche for stem cell differentiation toward testis-specific cell lineages.

METHODS

Rats' testes were decellularized by freeze-thaw cycle followed by immersion in deionized distilled water for 2 h, perfused with 1% Triton X-100 through ductus deferens for 4 h, 1% SDS for 48 h and 1% DNase for 2 h. The decellularized samples were prepared for further in vitro and in vivo analyses.

RESULT

Histochemical and immunohistochemistry studies revealed that ECM components such as Glycosaminoglycans (GAGs), neutral carbohydrate, elastic fibers, collagen I & IV, laminin, and fibronectin were well preserved, and the cells were completely removed after decellularization. Scanning electron microscopy (SEM) showed that 3D ultrastructure of the testis remained intact. In vivo and in vitro studies point out that decellularized scaffold was non-toxic and performed a good platform for cell division. In vivo implant of the scaffolds with or without mesenchymal stem cells (MSCs) showed that appropriate positions for transplantation were the mesentery and liver and the scaffolds could induce donor-loaded MSCs or host migrating cells to differentiate to the cells with phenotype of the sertoli- and leydig-like cells. The scaffolds also provide a good niche for migrating DAZL-positive cells; however, they could not differentiate into post meiotic-cell lineages.

CONCLUSION

The decellularized testis can be considered as a promising vehicle to support cell transplantation and may provide an appropriate niche for testicular cell differentiation.

Modulation of the transcriptomic profile of the R2C tumor Leydig cell line by the adipose tissue derived hormone leptin

Leptin is an important adipose derived hormone being secreted by adipocytes and involved in appetite regulation. Disruption of normal plasma levels of leptin has been associated with the pathogenesis of obesity. It is now well established that obesity is associated to an increased risk of cancer development, including testicular cancers. Recently, we have shown that high levels of leptin have inhibitory effects on cAMP-dependent steroidogenic genes expression in MA-10 Leydig cells. Hence, we examined if leptin could alter the transcriptome of the constitutively steroidogenic rat tumor Leydig cell line R2C. These cells were treated with high levels of leptin (1000 ng/ml) for 4 h, followed by mRNA extraction and RNA-Seq analysis. Interestingly, leptin had no effect on steroidogenic gene expression or pathways promoting tumorigenesis of this cell line. Genes being upregulated or downregulated by leptin were enriched in biological processes that were non-relevant to Leydig cell function. Surprisingly, lepr isoforms were weakly expressed in R2C cells and may explain in part the low levels of leptin's response for tumor Leydig cells. Hence, the current findings suggest that acute treatments of tumor Leydig cells with high levels of leptin have negligible effects on transcriptomics and rather supports that leptin would have a central effect on the hypothalamus to influence testicular function.

Differentiated osteoblasts derived decellularized extracellular matrix to promote osteogenic differentiation

Background

The extracellular matrix (ECM) can directly or indirectly influence on regulation of cell functions such as cell adhesion, migration, proliferation and differentiation. The cell derived ECM (CD-ECM) is a useful in vitro model for studying the comprehensive functions of CD-ECM because it maintains a native-like structure and composition. In this study, the CD-ECM is obtained and a test is carried out to determine the effectiveness of several combinations of decellularized methods. These methods were used to regulate the optimal ECM compositions to be induced by osteogenic differentiation using primary isolated osteoblasts.

Result

We investigated the effect of osteoblasts re-seeded onto normal osteoblast ECM under the growth medium (GM-ECM) and the osteogenic differentiation medium (OD-ECM). The osteoblasts were then cultured statically for 1, 2, and 4 weeks in a growth medium or differentiation medium. Before osteoblast culture, we performed immunostaining with filamentous actin and nuclei, and then performed DNA quantification. After each culture period, the osteogenic differentiation of the osteoblasts re-seeded on the OD-ECMs was enhanced osteogenic differentiation which confirmed by alkaline phosphatase staining and quantification, Alizarin Red S staining and quantification, and von Kossa staining. The OD-ECM-4 W group showed more effective osteogenic differentiation than GM-ECM and OD-ECM-2 W.

Conclusions

The OD-ECM-4 W has a better capacity in a microenvironment that supports osteogenic differentiation on the GM-ECM and OD-ECM-2 W. The ECM substrate has a wide range of applications as cell culture system or direct differentiation of stem cell and excellent potential as cell-based tissue repair in orthopedic tissue engineering.

Transcriptional profiling validates involvement of extracellular matrix and proteinases genes in mouse gonad development

Extracellular matrix (ECM) plays an important scaffolding role in the establishment of organs structure during development. A great number of ECM components and enzymes (proteinases) regulating formation/degradation of ECM during organ remodeling have been identified. In order to study the role of ECM in the mouse gonad development, especially during sexual differentiation of the gonads when the structure of the testis and ovary becomes established, we performed a global analysis of transcriptome in three main cell types of developing gonad (supporting, interstitial/stromal and germ cells) using transgenic mice, cell sorting and microarray. The genes coding for ECM components were mostly expressed in two gonadal cell lines: supporting and interstitial/stromal cells. These two cell lines differed in the expression pattern of ECM components, which suggests that ECM components might be crucial for differentiation of gonad compartments (for example testis cords vs. interstitium in XY gonads). Collagens and proteoglycans coding genes were mainly expressed in the interstitium/stromal cells, while non-collagen glycoproteins and matricellular coding genes were expressed in both cell lines. We also analyzed the expression of genes encoding ECM enzymes that are secreted to the ECM where they remodel the scaffolding of developing organs. We found that the ECM enzyme genes were also mostly expressed in supporting and interstitial/stromal cells. In contrast to the somatic cells, the germ cells expressed only limited number of ECM components and enzymes. This suggests that the germ line cells do not participate, or play only a minor role, in the sculpting of the gonad structure via ECM synthesis and remodeling. Importantly, the supporting cells showed the sex-specific pattern of expression of ECM components. However, the pattern of expression of most ECM enzymes in the somatic and germ cells is independent on the sex of the gonad. Further studies are required to elucidate the exact roles of identified genes in sexual differentiation of the gonads.

Transcriptomic responses to environmental temperature by turtles with temperature-dependent and genotypic sex determination assessed by RNAseq inform the genetic architecture of embryonic gonadal development

Vertebrate sexual fate is decided primarily by the individual's genotype (GSD), by the environmental temperature during development (TSD), or both. Turtles exhibit TSD and GSD, making them ideal to study the evolution of sex determination. Here we analyze temperature-specific gonadal transcriptomes (RNA-sequencing validated by qPCR) of painted turtles (Chrysemys picta TSD) before and during the thermosensitive period, and at equivalent stages in soft-shell turtles (Apalone spinifera-GSD), to test whether TSD's and GSD's transcriptional circuitry is identical but deployed differently between mechanisms. Our data show that most elements of the mammalian urogenital network are active during turtle gonadogenesis, but their transcription is generally more thermoresponsive in TSD than GSD, and concordant with their sex-specific function in mammals [e.g., upregulation of Amh, Ar, Esr1, Fog2, Gata4, Igf1r, Insr, and Lhx9 at male-producing temperature, and of β-catenin, Foxl2, Aromatase (Cyp19a1), Fst, Nf-kb, Crabp2 at female-producing temperature in Chrysemys]. Notably, antagonistic elements in gonadogenesis (e.g., β-catenin and Insr) were thermosensitive only in TSD early-embryos. Cirbp showed warm-temperature upregulation in both turtles disputing its purported key TSD role. Genes that may convert thermal inputs into sex-specific development (e.g., signaling and hormonal pathways, RNA-binding and heat-shock) were differentially regulated. Jak-Stat, Nf-κB, retinoic-acid, Wnt, and Mapk-signaling (not Akt and Ras-signaling) potentially mediate TSD thermosensitivity. Numerous species-specific ncRNAs (including Xist) were differentially-expressed, mostly upregulated at colder temperatures, as were unannotated loci that constitute novel TSD candidates. Cirbp showed warm-temperature upregulation in both turtles. Consistent transcription between turtles and alligator revealed putatively-critical reptilian TSD elements for male (Sf1, Amh, Amhr2) and female (Crabp2 and Hspb1) gonadogenesis. In conclusion, while preliminary, our data helps illuminate the regulation and evolution of vertebrate sex determination, and contribute genomic resources to guide further research into this fundamental biological process.

High levels of the extracellular matrix proteoglycan decorin are associated with inhibition of testicular function

Decorin (DCN), a component of the extracellular matrix of the peritubular wall and the interstitial areas of the human testis, can interact with growth factor (GF) signalling, thereby blocking downstream actions of GFs. In the present study the expression and regulation of DCN using both human testes and two experimental animal models, namely the rhesus monkey and mouse, were examined. DCN protein was present in peritubular and interstitial areas of adult human and monkey testes, while it was almost undetectable in adult wild type mice. Interestingly, the levels and sites of testicular DCN expression in the monkeys were inversely correlated with testicular maturation markers. A strong DCN expression associated with the abundant connective tissue of the interstitial areas in the postnatal through pre-pubertal phases was observed. In adult and old monkeys the DCN pattern was similar to the one in normal human testes, presenting strong expression at the peritubular region. In the testes of both infertile men and in a mouse model of inflammation associated infertility (aromatase-overexpressing transgenic mice), the fibrotic changes and increased numbers of tumour necrosis factor (TNF)-α-producing immune cells were shown to be associated with increased production of DCN. Furthermore, studies with human testicular peritubular cells isolated from fibrotic testis indicated that TNF-α significantly increased DCN production. The data, thus, show that an increased DCN level is associated with impaired testicular function, supporting our hypothesis that DCN interferes with paracrine signalling of the testis in health and disease.

Regulation of osteogenic differentiation of rat bone marrow stromal cells on 2D nanorod substrates

Bone marrow stromal cells (BMSCs) possess multi-lineage differentiation potential and can be induced to undergo differentiation into various cell types with the correct combination of chemical and environmental factors. Although, they have shown great prospects in therapeutic and medical applications, less is known about their behavior on nanosurfaces mimicking the extra cellular matrix (ECM). In this report we have employed 2D substrates coated with tobacco mosaic virus (TMV) nanorods to study the differentiation process of BMSCs into osteoblast like cells. TMV is a rod-shaped plant virus with an average length of 300 nm and diameter of 18 nm. The osteogenic differentiation of BMSCs on TMV was studied over time points of 7, 14 and 21 days. We examined the temporal gene expression changes during these time points by real-time quantitative PCR (RT-qPCR) analysis. As expected, osteo-specific genes (osteocalcin, osteopontin and osteonectin) were upregulated and showed a maximum change in expression on TMV at 14 days which was 7 days earlier than on tissue culture plastic (TCP). Based on the genes expression profile generated by RT-qPCR experiments, we proposed that the early interaction of cells with TMV triggers on signaling pathways which regulate speedy expression of osteocalcin in turn, resulting in early mineralization of the cells. To further investigate these regulating factors we studied global changes in gene expression (DNA microarray analyses) during osteogenic differentiation on the nanosubstrate. Multitudes of genes were affected by culturing cells on nanorod substrate, which corroborated our initial PCR findings. Microarray analysis further revealed additional targets influenced by the presence of nanorods on the surface, of which, the expression of bone morphogenetic protein 2 (BMP2) was of particular interests. Further investigation into the temporal change of BMP2, revealed that it acts as a major promoter in signaling the early regulation of osteocalcin on TMV coated substrates.

The estrous cycle modulates small leucine-rich proteoglycans expression in mouse uterine tissues

In the pregnant mouse uterus, small leucine-rich proteoglycans (SLRPs) are drastically remodeled within a few hours after fertilization, suggesting that ovarian hormone levels modulate their synthesis and degradation. In this study, we followed by immunoperoxidase approach, the presence of four members of the SLRP family (decorin, lumican, biglycan, and fibromodulin) in the uterine tissues along the estrous cycle of the mouse. All molecules except fibromodulin, which predominates in the myometrium, showed a striking modulation in their distribution in the endometrial stroma, following the rise in the level of estrogen. Moreover, notable differences in the distribution of SLRPs were observed between superficial and deep stroma, as well as between the internal and external layers of the myometrium. Only biglycan and fibromodulin were expressed in the luminal and glandular epithelia. All four SLRPs were found in cytoplasmic granules of mononucleated cells. The pattern of distribution of the immunoreaction for these molecules in the uterine tissues was found to be estrous cycle-stage dependent, suggesting that these molecules undergo ovarian hormonal control and probably participate in the preparation of the uterus for decidualization and embryo implantation. In addition, this and previous results from our laboratory suggest the existence of two subpopulations of endometrial fibroblasts that may be related to the centrifugal development of the decidua. Anat Rec, 2008. (c) 2008 Wiley-Liss, Inc.

Human primary corneal fibroblasts synthesize and deposit proteoglycans in long-term 3-D cultures

Our goal was to develop a 3-D multi-cellular construct using primary human corneal fibroblasts cultured on a disorganized collagen substrate in a scaffold-free environment and to use it to determine the regulation of proteoglycans over an extended period of time (11 weeks). Electron micrographs revealed multi-layered constructs with cells present in between alternating parallel and perpendicular arrays of fibrils. Type I collagen increased 2-4-fold. Stromal proteoglycans including lumican, syndecan4, decorin, biglycan, mimecan, and perlecan were expressed. The presence of glycosaminoglycan chains was demonstrated for a subset of the core proteins (lumican, biglycan, and decorin) using lyase digestion. Cuprolinic blue-stained cultures showed that sulfated proteoglycans were present throughout the construct and most prominent in its mid-region. The size of the Cuprolinic-positive filaments resembled those previously reported in a human corneal stroma. Under the current culture conditions, the cells mimic a development or nonfibrotic repair phenotype.