scholarly journals Constitutive activation of CTNNB1 results in a loss of spermatogonial stem cell activity in mice

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251911
Author(s):  
Alexandre Boyer ◽  
Xiangfan Zhang ◽  
Adrien Levasseur ◽  
Nour Abou Nader ◽  
Guillaume St-Jean ◽  
...  

Spermatogenesis requires that a careful balance be maintained between the self-renewal of spermatogonial stem cells (SSCs) and their commitment to the developmental pathway through which they will differentiate into spermatozoa. Recently, a series of studies employing various in vivo and in vitro models have suggested a role of the wingless-related MMTV integration site gene family/beta-catenin (WNT/CTNNB1) pathway in determining the fate of SSCs. However, conflicting data have suggested that CTNNB1 signaling may either promote SSC self-renewal or differentiation. Here, we studied the effects of sustained CTNNB1 signaling in SSCs using the Ctnnb1tm1Mmt/+; Ddx4-CreTr/+ (ΔCtnnb1) mouse model, in which a stabilized form of CTNNB1 is expressed in all germ cells. ΔCtnnb1 mice were found to have reduced testis weights and partial germ cell loss by 4 months of age. Germ cell transplantation assays showed a 49% reduction in total functional SSC numbers in 8 month-old transgenic mice. In vitro, Thy1-positive undifferentiated spermatogonia from ΔCtnnb1 mice formed 57% fewer clusters, which was associated with decreased cell proliferation. A reduction in mRNA levels of genes associated with SSC maintenance (Bcl6b, Gfra1, Plzf) and increased levels for markers associated with progenitor and differentiating spermatogonia (Kit, Rarg, Sohlh1) were detected in these cluster cells. Furthermore, RNAseq performed on these clusters revealed a network of more than 900 genes regulated by CTNNB1, indicating that CTNNB1 is an important regulator of spermatogonial fate. Together, our data support the notion that CTNNB1 signaling promotes the transition of SSCs to undifferentiated progenitor spermatogonia at the expense of their self-renewal.

2006 ◽  
Vol 18 (2) ◽  
pp. 110 ◽  
Author(s):  
D. Pant ◽  
C. Keefer

Genetic modification of embryonic stem (ES) cells derived from domestic species could be exploited to produce transgenic animals; however, fully validated ES have not been obtained in domestic species. Recent findings regarding key transcription factors and regulation of pluripotency and self-renewal in murine ES cells may provide keys to enable the derivation of ES in domestic species. The aim of this study was to identify and monitor the expression of candidate genes, which are known to be involved in the maintenance of self-renewal and pluripotency in mouse and human ES cells, during the critical first steps in establishment of primary cultures. Inner cell masses (ICMs) were isolated via manual dissection of 25 to 30 commercial in vitro-produced (IVP) blastocysts (Bomed, Inc., Madison, WI, USA) in each of three separate replicates and from 10 in vivo-derived Day 7-8 bovine blastocysts. On the day of ICM isolation (Day 0), 4-5 ICM clumps were collected for RT-PCR analysis. The remaining isolated ICMs were cultured (4-5 ICM clumps per well) on mitomycin C (Sigma-Aldrich, St. Louis, MO, USA)-inactivated mouse embryonic fibroblasts (STO, ATCC, Manassas, VA, USA). The ICM clumps were cultured in 12-well tissue culture dishes in ES medium consisting of Knockout DMEM (Invitrogen, Carlsbad, CA, USA) supplemented with 15% FCS (Hyclone, Logan, UT, USA), 2 mM l-glutamine (Invitrogen), 0.1 mM 2-mercaptoethanol (MP Biomedicals, Irvine, CA, USA), and non-essential amino acids (Sigma). Two to four cultured ICM clumps were collected for RT-PCR analysis on Days 1-4 from IVP embryos and on Days 2, 4, and 6 from in vivo-derived embryos. Total RNA was extracted from the collected samples using the Absolutely RNA Nanoprep Kit (Strategene, La Jolla, CA, USA). First-strand DNAs were synthesized using Superscript III (Invitrogen) and cDNAs were amplified with PfuUltra hotstart PCR mastermix (Stratagene). Primers were designed based on homology between human and mouse sequences and were validated using bovine tissues. In experiments spanning these critical first few days of culture, the pluripotency-related genes (Nanog, Oct-4, Sox-2) and components of the LIF (LIFR, Gp130), BMP (Bmpr1a, Id-1), and Wnt (Beta-catenin, Frizzled) pathways were expressed in the ICM cultures over the 4 days of IVP-ICM cultures and the 6 days of in vivo-derived ICM cultures. These results indicate that the markers of pluripotency and the components of signaling pathways implicated in the maintenance of murine embryonic stem cells are present in ICMs of Day 7-8 bovine blastocysts and continue to be expressed at least during the initial days of culture. Genes (NCAM, Lef1) associated with early differentiation, however, were also expressed. Whether their expression is an indicator of ICM differentiation or of residual contamination with trophectoderm remains to be determined. Further studies will determine whether stimulation of these pathways can facilitate efficient derivation and maintenance ruminant ES cells.


2021 ◽  
Vol 8 ◽  
Author(s):  
Paloma Cordero ◽  
Alejandra Guerrero-Moncayo ◽  
Monica De los Reyes ◽  
Manuel Varas-Godoy ◽  
Jahaira Cortez ◽  
...  

In vitro gamete derivation from stem cells has potential applications in animal reproduction as an alternative method for the dissemination of elite animal genetics, production of transgenic animals, and conservation of endangered species. Mesenchymal stem cells (MSCs) may be suitable candidates for in vitro gamete derivation considering their differentiative capacity and their potential for cell therapy. Due to its relevance in gametogenesis, it has been reported that retinoic acid (RA) and bone morphogenetic protein (BMP) 4 are able to upregulate the expression of specific markers associated to the early stages of germ cell (GCs) differentiation in bovine fetal MSCs (bfMSCs). In the present study, we used polycistronic vectors containing combinations of GC genes DAZL, STRA8, and BOULE followed by exposure to BMP4 or RA to induce GC differentiation of bovine fetal adipose tissue-derived MSC (AT-MSCs). Cells samples at Day 14 were analyzed according to the expression of pluripotent genes NANOG and OCT4 and GC genes DAZL, STRA8, BOULE, PIWI, c-KIT, and FRAGILIS using Q-PCR. Fetal and adult testis and AT-MSCs samples were also analyzed for the expression of DAZL, STRA8, and NANOG using immunofluorescence. Increased gene expression levels in the adult testis and cell-specific distribution of DAZL, STRA8, and NANOG in the fetal testis suggest that these markers are important components of the regulatory network that control the in vivo differentiation of bovine GCs. Overexpression of DAZL and STRA8 in bi-cistronic and DAZL, STRA8, and BOULE in tri-cistronic vectors resulted in the upregulation of OCT4, NANOG, and PIWIL2 in bovine fetal AT-MSCs. While BMP4 repressed NANOG expression, this treatment increased DAZL and c-KIT and activated FRAGILIS expression in bovine fetal AT-MSCs. Treatment with RA for 14 days increased the expression of DAZL and FRAGILIS and maintained the mRNA levels of STRA8 in bovine fetal AT-MSCs transfected with bi-cistronic and tri-cistronic vectors. Moreover, RA treatment repressed the expression of OCT4 and NANOG in these cells. Thus, overexpression of DAZL, STRA8, and BOULE induced the upregulation of the pluripotent markers and PIWIL2 in transfected bovine fetal AT-MSCs. The partial activation of GC gene expression by BMP4 and RA suggests that both factors possess common targets but induce different gene expression effects during GC differentiation in overexpressing bovine fetal AT-MSCs.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Federica Tonon ◽  
Giovanni Giuseppe Giobbe ◽  
Alessandro Zambon ◽  
Camilla Luni ◽  
Onelia Gagliano ◽  
...  

Abstract Among the multiple metabolic signals involved in the establishment of the hepatic zonation, oxygen could play a key role. Indeed, depending on hepatocyte position in the hepatic lobule, gene expression and metabolism are differently affected by the oxygen gradient present across the lobule. The aim of this study is to understand whether an oxygen gradient, generated in vitro in our developed device, is sufficient to instruct a functional metabolic zonation during the differentiation of human embryonic stem cells (hESCs) from endoderm toward terminally differentiated hepatocytes, thus mimicking the in vivo situation. For this purpose, a microfluidic device was designed for the generation of a stable oxygen gradient. The oxygen gradient was applied to differentiating hESCs at the pre-hepatoblast stage. The definitive endoderm and hepatic endoderm cells were characterized by the expression of the transcription factor SOX-17 and alpha-fetoprotein (AFP). Immature and mature hepatocytes were characterized by hepatocyte nuclear factor 4-alpha (HNF-4α) and albumin (ALB) expression and also analyzed for cytochrome P450 (CYP3A4) zonation and glycogen accumulation through PAS staining. Metabolic zonated genes expression was assessed through quantitative real time PCR. Application of the oxygen gradient during differentiation induced zonated glycogen storage, which was higher in the hepatocytes grown in high pO2 compared to those grown in low pO2. The mRNA levels of glutamine synthetase (GLUL), beta-catenin (CTNNB) and its direct target cyclin D1 (CCND1) showed significantly higher expression in the cells grown in low pO2 compared to those grown in high pO2. On the contrary, carbamoyl-phosphate synthetase 1 (CPS1), ALB, the proliferative marker ki67 (MKI67) and cyclin A (CCNA) resulted to be significantly higher expressed in cells cultured in high pO2 compared to those cultured in low pO2. These results indicate that the oxygen gradient generated in our device can instruct the establishment of a functional metabolic zonation in differentiating hESCs. The possibility to obtain differentiated hepatocytes in vitro may allow in the future to deepen our knowledge about the physiology/pathology of hepatocytes in relation to the oxygen content.


Endocrinology ◽  
2014 ◽  
Vol 155 (12) ◽  
pp. 4964-4974 ◽  
Author(s):  
Liang-Yu Chen ◽  
Paula R. Brown ◽  
William B. Willis ◽  
Edward M. Eddy

Peritubular myoid (PM) cells surround the seminiferous tubule and together with Sertoli cells form the cellular boundary of the spermatogonial stem cell (SSC) niche. However, it remains unclear what role PM cells have in determining the microenvironment in the niche required for maintenance of the ability of SSCs to undergo self-renewal and differentiation into spermatogonia. Mice with a targeted disruption of the androgen receptor gene (Ar) in PM cells experienced a progressive loss of spermatogonia, suggesting that PM cells require testosterone (T) action to produce factors influencing SSC maintenance in the niche. Other studies showed that glial cell line-derived neurotrophic factor (GDNF) is required for SSC self-renewal and differentiation of SSCs in vitro and in vivo. This led us to hypothesize that T-regulated GDNF expression by PM cells contributes to the maintenance of SSCs. This hypothesis was tested using an adult mouse PM cell primary culture system and germ cell transplantation. We found that T induced GDNF expression at the mRNA and protein levels in PM cells. Furthermore, when thymus cell antigen 1-positive spermatogonia isolated from neonatal mice were cocultured with PM cells with or without T and transplanted to the testes of germ cell-depleted mice, the number and length of transplant-derived colonies was increased considerably by in vitro T treatment. These results support the novel hypothesis that T-dependent regulation of GDNF expression in PM cells has a significant influence on the microenvironment of the niche and SSC maintenance.


Author(s):  
B. Manoranjan ◽  
S. Mahendram ◽  
D. Bakhshinyan ◽  
M. Kameda-Smith ◽  
C. Venugopal ◽  
...  

Brain tumours represent the leading cause of childhood cancer mortality, of which medulloblastoma (MB) is the most frequent malignant pediatric brain tumour. Current molecular Nsubgroups of MB recognize distinct disease entities of which activated Wnt signaling (monosomy 6, exon 3 mutations in CTNNB1, and Wnt gene signature) is associated with a distinct subgroup and the best overall outcome. In contrast, only non-Wnt MBs are characterized by metastatic disease, increased rate of recurrence, and poor overall survivorship. Given the excellent clinical outcome in patients with Wnt-driven MB, we aimed to convert treatment-resistant MB subgroups into an ostensibly benign tumour through selective targeting by small molecule Wnt agonists (Wnt3A), GSK3 inhibitors (CHIR99021), and transgenic lines containing a stabilized beta-catenin mutant. Activated Wnt signaling resulted in decreased in vitro self-renewal and promoted differentiation within primary human MB stem cells. The clinical relevance of these findings were demonstrated with an in vivo survival advantage in mice containing orthotopic injections of cells containing a stabilized beta-catenin mutant representative of constitutively active Wnt signaling. Xenografts generated from Wnt-activated tumours were much smaller in size, maintained a much lower rate of proliferation, and reduction in key MB stem cell self-renewal genes (Bmi1, Sox2, Msi1, FoxG1). Our work establishes activated Wnt signaling as a novel treatment paradigm in childhood MB, while providing evidence for the context-specific tumour suppressive function of the canonical Wnt pathway.


Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Tatenda Mahlokozera ◽  
Mounica Paturu ◽  
Daniel Hafez ◽  
Diane Mao ◽  
Albert H Kim

Abstract INTRODUCTION Glioblastomas harbor inter and intratumoral genetic diversity, posing a challenge for targeted therapies. A major question is whether shared mechanisms might control the malignant phenotypes of genetically diverse glioblastoma cells. We reasoned that ubiquitin-dependent regulation of pluripotency-related transcription factor SOX2, which is indispensable for the maintenance of tumorigenic glioblastoma stem-like cells (GSC), may represent one such mechanism. TRIM26, an E3-ubiquitin ligase with immune-related functions, is highly expressed in glioblastoma tumors compared to normal brain. Immunoprecipitation followed by mass spectrometry suggested TRIM26 interacts with SOX2. We hypothesized that TRIM26 plays an essential role in GSCs by regulating SOX2 function. METHODS Direct protein-protein interactions were assessed by in vitro binding assays. In Vitro ubiquitination assays were performed. Lentiviral TRIM26 overexpression and knockdown were used to test the role of TRIM26 in regulating SOX2 stability, activity, and ubiquitination. The functional relevance of TRIM26 in GSCs was assessed by in Vitro self-renewal and in Vivo tumorigenicity assays. RESULTS We found that TRIM26 directly interacts with SOX2 via the C-terminal PRY-SPRY domain. Unexpectedly, TRIM26 overexpression resulted in decreased SOX2 polyubiquitination in cells. In line with this observation, TRIM26 knockdown in GSCs decreased SOX2 protein stability without changing SOX2 mRNA levels. Functionally, TRIM26 knockdown reduced SOX2 transcriptional activity, self-renewal, and in Vivo tumorigenicity in multiple genetically divergent GSC lines. Mechanistically, we discovered TRIM26 stabilizes SOX2 protein by competitively reducing the interaction of SOX2 with WWP2, a bonafide SOX2 E3 ligase in GSCs. Accordingly; WWP2 depletion in the setting of TRIM26 knockdown in GSCs rescued SOX2 protein levels, self-renewal, and tumorigenicity. CONCLUSION Together, these results suggest that TRIM26 maintains GSCs by protecting SOX2 from WWP2-mediated ubiquitination and subsequent proteasomal degradation. These findings raise the intriguing possibility that modulating ubiquitin-dependent regulation of SOX2 in genetically heterogeneous GSCs may represent a unifying therapeutic strategy.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2459-2459
Author(s):  
Eric Deneault ◽  
Sonia Cellot ◽  
Amélie Faubert ◽  
Jean-Philippe Laverdure ◽  
Mélanie Fréchette ◽  
...  

Abstract The maintenance of blood homeostasis depends on hematopoietic stem cells (HSCs), which rely on two critical properties, namely multipotency and self-renewal. The former enables differentiation into multiple lineages, the latter ensures preservation of fate upon cellular division. By definition, a self-renewal division implies that a HSC is permissive to cell cycle entry, while restrained from engaging in differentiation, apoptosis or senescence pathways. Despite the tremendous progress made towards the identification of the molecular circuitry that governs ESC fate, genes controlling this process in adult HSCs have proven more difficult to unmask. This is principally due to our inability to maintain or expand HSC ex vivo as homogenous populations, to the absence of a stringent surrogate marker to follow the HSC multipotent state and to changes in cell phenotype observed shortly upon facing the selective pressures of in vitro culture conditions, impeding HSC tracking in this context. We now report the results of a novel in vitro to in vivo functional screen, which identified a series of nuclear factors that induced high levels of HSC activity similar to that previously achieved with Hoxb4. We created a database consisting of 689 nuclear factors considered as potential candidate regulators of HSC activity. This list was mostly derived from microarray gene expression profiling of normal and leukemia stem cells including our recently generated FLA2 leukemia (1 in 1.5 cells are leukemia stem cells, G.S. et coll., in preparation). It was also enriched by genes obtained following a review of the literature on stem cell self-renewal. Genes in this database were next ranked from 1 (lowest priority) to 10 (highest priority) based on 3 factors: differential expression between primitive and more mature cellular fractions (e.g., LT-HSC-enriched: 3 points), expression levels (high, highest priority: max 3 points) and the consistency of findings between datasets (max 4 points). Genes with a score of 6 and above (n=139) were selected for functional studies, of which 104 were tested in HSCs, using a high-throughput overexpression in vitro to in vivo assay tailored to circumvent current limitations imposed by the biology of HSCs. In total, 18 new determinants have emerged, 11 of which act in a cell autonomous manner, namely Ski, Smarcc1, Vps72, Trim27, Sox4, Klf10, Prdm16, Erdr1, Cnbp, Xbp1 and Hnrpdl, while the remaining provide a non-autonomous influence on HSC activity, i.e, Fos, Hmgb1, Tcfec, Sfpi1, Zfp472, Hdac1 and Pml. Clonal and phenotypic analyses of hematopoietic tissues derived from selected recipients confirmed that the majority of these factors induced HSC expansion in vitro without perturbing their differentiation in vivo. Epistatic analyses further reveals that 3 of the most potent candidates, namely Ski, Prdm16 and Klf10 may exploit both mechanisms, i.e., cell and non-cell autonomous. The utilization of this novel screening method together with the creation of a database enriched for potential determinants and candidate regulators of adult stem cell activity can now be exploited to devise regulatory networks in these cells.


2020 ◽  
Vol 26 (45) ◽  
pp. 5783-5792
Author(s):  
Kholood Abid Janjua ◽  
Adeeb Shehzad ◽  
Raheem Shahzad ◽  
Salman Ul Islam ◽  
Mazhar Ul Islam

There is compelling evidence that drug molecules isolated from natural sources are hindered by low systemic bioavailability, poor absorption, and rapid elimination from the human body. Novel approaches are urgently needed that could enhance the retention time as well as the efficacy of natural products in the body. Among the various adopted approaches to meet this ever-increasing demand, nanoformulations show the most fascinating way of improving the bioavailability of dietary phytochemicals through modifying their pharmacokinetics and pharmacodynamics. Curcumin, a yellowish pigment isolated from dried ground rhizomes of turmeric, exhibits tremendous pharmacological effects, including anticancer activities. Several in vitro and in vivo studies have shown that curcumin mediates anticancer effects through the modulation (upregulation and/or downregulations) of several intracellular signaling pathways both at protein and mRNA levels. Scientists have introduced multiple modern techniques and novel dosage forms for enhancing the delivery, bioavailability, and efficacy of curcumin in the treatment of various malignancies. These novel dosage forms include nanoparticles, liposomes, micelles, phospholipids, and curcumin-encapsulated polymer nanoparticles. Nanocurcumin has shown improved anticancer effects compared to conventional curcumin formulations. This review discusses the underlying molecular mechanism of various nanoformulations of curcumin for the treatment of different cancers. We hope that this study will make a road map for preclinical and clinical investigations of cancer and recommend nano curcumin as a drug of choice for cancer therapy.


2021 ◽  
Vol 19 ◽  
pp. 228080002110068
Author(s):  
Hsien-Te Chen ◽  
Hsin-I Lin ◽  
Chi-Jen Chung ◽  
Chih-Hsin Tang ◽  
Ju-Liang He

Here, we present a bone implant system of phase-oriented titanium dioxide (TiO2) fabricated by the micro-arc oxidation method (MAO) on β-Ti to facilitate improved osseointegration. This (101) rutile-phase-dominant MAO TiO2 (R-TiO2) is biocompatible due to its high surface roughness, bone-mimetic structure, and preferential crystalline orientation. Furthermore, (101) R-TiO2 possesses active and abundant hydroxyl groups that play a significant role in enhancing hydroxyapatite formation and cell adhesion and promote cell activity leading to osseointegration. The implants had been elicited their favorable cellular behavior in vitro in the previous publications; in addition, they exhibit excellent shear strength and promote bone–implant contact, osteogenesis, and tissue formation in vivo. Hence, it can be concluded that this MAO R-TiO2 bone implant system provides a favorable active surface for efficient osseointegration and is suitable for clinical applications.


BMC Cancer ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Chengwu Xiao ◽  
Wei Zhang ◽  
Meimian Hua ◽  
Huan Chen ◽  
Bin Yang ◽  
...  

Abstract Background The tripartite motif (TRIM) family proteins exhibit oncogenic roles in various cancers. The roles of TRIM27, a member of the TRIM super family, in renal cell carcinoma (RCC) remained unexplored. In the current study, we aimed to investigate the clinical impact and roles of TRIM27 in the development of RCC. Methods The mRNA levels of TRIM27 and Kaplan–Meier survival of RCC were analyzed from The Cancer Genome Atlas database. Real-time PCR and Western blotting were used to measure the mRNA and protein levels of TRIM27 both in vivo and in vitro. siRNA and TRIM27 were exogenously overexpressed in RCC cell lines to manipulate TRIM27 expression. Results We discovered that TRIM27 was elevated in RCC patients, and the expression of TRIM27 was closely correlated with poor prognosis. The loss of function and gain of function results illustrated that TRIM27 promotes cell proliferation and inhibits apoptosis in RCC cell lines. Furthermore, TRIM27 expression was positively associated with NF-κB expression in patients with RCC. Blocking the activity of NF-κB attenuated the TRIM27-mediated enhancement of proliferation and inhibition of apoptosis. TRIM27 directly interacted with Iκbα, an inhibitor of NF-κB, to promote its ubiquitination, and the inhibitory effects of TRIM27 on Iκbα led to NF-κB activation. Conclusions Our results suggest that TRIM27 exhibits an oncogenic role in RCC by regulating NF-κB signaling. TRIM27 serves as a specific prognostic indicator for RCC, and strategies targeting the suppression of TRIM27 function may shed light on future therapeutic approaches.


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