Human sarcomas have been modeled in mice by expression of specific fusion genes in mesenchymal stem cells (MSCs). However, sarcoma models based on human MSCs are still missing. We attempted to ...develop a model of liposarcoma by expressing FUS (FUsed in Sarcoma; also termed TLS, Translocated in LipoSarcoma)‐CHOP (C/EBP HOmologous Protein; also termed DDIT3, DNA Damage‐Inducible Transcript 3), a hallmark mixoid liposarcoma‐associated fusion oncogene, in wild‐type and p53‐deficient mouse and human adipose‐derived mesenchymal stem/stromal cells (ASCs). FUS‐CHOP induced liposarcoma‐like tumors when expressed in p53−/− but not in wild‐type (wt) mouse ASCs (mASCs). In the absence of FUS‐CHOP, p53−/− mASCs forms leiomyosarcoma, indicating that the expression of FUS‐CHOP redirects the tumor genesis/phenotype. FUS‐CHOP expression in wt mASCs does not initiate sarcomagenesis, indicating that p53 deficiency is required to induce FUS‐CHOP‐mediated liposarcoma in fat‐derived mASCs. In a human setting, p53‐deficient human ASCs (hASCs) displayed a higher in vitro growth rate and a more extended lifespan than wt hASCs. However, FUS‐CHOP expression did not induce further changes in culture homeostasis nor initiated liposarcoma in either wt or p53‐depleted hASCs. These results indicate that FUS‐CHOP expression in a p53‐deficient background is sufficient to initiate liposarcoma in mouse but not in hASCs, suggesting the need of additional cooperating mutations in hASCs. A microarray gene expression profiling has shed light into the potential deregulated pathways in liposarcoma formation from p53‐deficient mASCs expressing FUS‐CHOP, which might also function as potential cooperating mutations in the transformation process from hASCs. STEM CELLS 2011; 29:179–192
ABSTRACT
MicroRNAs (miRNAs) have been shown to be important in early development and maintenance of human embryonic stem cells (hESCs). The miRNA miR‐302–367 is specifically expressed in hESCs, and ...its expression decays on differentiation. We previously identified the structure of the gene coding for the human miR‐302–367 cluster and characterized its promoter. The promoter activity was functionally validated in hESCs, opening up new avenues to further investigate how these miRNA molecules fit in the complex molecular network conferring “sternness” properties to hESCs. The physiological roles of specific miRNA‐mRNA interactions remain largely unknown. Here, we investigated putative miR‐302–367 mRNA targets in hESCs, potentially relevant for ESC biology. We found that the Nodal inhibitors Lefty1 and Lefty2 are post‐transcriptionally targeted by miR‐302s in hESCs. Functional analyses indicate that miR‐302s negatively modulate the level of lefties, and become upstream regulators of the TGFβ/Nodal pathway, functioning via Smad‐2/3 signaling. Overexpression of the miR‐302–367 cluster in hESCs causes a delay in early hESC differentiation, as measured by enhanced levels of ESC‐specific transcription factors, coupled to a faster teratoma formation in mice transplanted with miR‐302–367‐expressing hESCs and a concomitant impairment of germ layer specification, displaying robust decreased levels of early mesodermal, endodermal, and ectoder‐mal specific markers. These findings suggest that Lefty is negatively modulated by miR‐302s in hESCs, which plays an important role in maintaining the balance between pluripotency and germ layer specification.—Barroso‐delJesus, A., Lucena‐Aguilar, G., Sanchez, L., Ligero, G., Gutierrez‐Aranda, I., Menendez, P. The Nodal inhibitor Lefty is negatively modulated by the microRNA miR‐302 in human embryonic stem cells. FASEB J. 25, 1497–1508 (2011). www.fasebj.org
Laser guide stars employed at astronomical observatories provide artificial wavefront reference sources to help correct (in part) the impact of atmospheric turbulence on astrophysical observations. ...Following the recent commissioning of the 4 Laser Guide Star Facility (4LGSF) on Unit Telescope 4 (UT4) of the Very Large Telescope (VLT), we characterize the spectral signature of the uplink beams from the 22-W lasers to assess the impact of laser scattering from the 4LGSF on science observations. We use the Multi-Unit Spectroscopic Explorer (MUSE) optical integral field spectrograph mounted on the Nasmyth B focus of UT4 to acquire spectra at a resolution of R≅3000 of the uplink laser beams over the wavelength range of 4750 Å–9350 Å. We report the first detection of laser-induced Raman scattering by N2 , O2 , CO2 , H2O , and (tentatively) CH4 molecules in the atmosphere above the astronomical observatory of Cerro Paranal. In particular, our observations reveal the characteristic spectral signature of laser photons—but 480 Å to 2210 Å redder than the original laser wavelength of 5889.959 Å—landing on the 8.2-m primary mirror of UT4 after being Raman-scattered on their way up to the sodium layer. Laser-induced Raman scattering, a phenomenon not usually discussed in the astronomical context, is not unique to the observatory of Cerro Paranal, but it is common to any astronomical telescope employing a laser guide star (LGS) system. It is thus essential for any optical spectrograph coupled to a LGS system to thoroughly handle the possibility of a Raman spectral contamination via a proper baffling of the instrument and suitable calibrations procedures. These considerations are particularly applicable for the HARMONI optical spectrograph on the upcoming Extremely Large Telescope (ELT). At sites hosting multiple telescopes, laser-collision-prediction tools should also account for the presence of Raman emission from the uplink laser beam(s) to avoid the unintentional contamination of observations acquired with telescopes in the vicinity of a LGS system.
Human ESCs provide access to the earliest stages of human development and may serve as an unlimited source of functional cells for future cell therapies. The optimization of methods directing the ...differentiation of human embryonic stem cells (hESCs) into tissue‐specific precursors becomes crucial. We report an efficient enrichment of mesenchymal stem cells (MSCs) from hESCs through specific inhibition of SMAD‐2/3 signaling. Human ESC‐derived MSCs (hESC‐MSCs) emerged as a population of fibroblastoid cells expressing a MSC phenotype: CD73+ CD90+ CD105+ CD44+ CD166+ CD45− CD34− CD14− CD19− human leucocyte antigen‐DR (HLA‐DR)−. After 28 days of SMAD‐2/3 inhibition, hESC cultures were enriched (>42%) in multipotent MSCs. CD73+CD90+ hESC‐MSCs were fluorescence activated cell sorting (FACS)‐isolated and long‐term cultures were established and maintained for many passages displaying a faster growth than somatic tissue‐derived MSCs while maintaining MSC morphology and phenotype. They displayed osteogenic, adipogenic, and chondrocytic differentiation potential and exhibited potent immunosuppressive and anti‐inflammatory properties in vitro and in vivo, where hESC‐MSCs were capable of protecting against an experimental model of inflammatory bowel disease. Interestingly, the efficient enrichment of hESCs into MSCs through inhibition of SMAD‐2/3 signaling was not reproducible with distinct induced pluripotent stem cell lines. Our findings provide mechanistic insights into the differentiation of hESCs into immunosuppressive and anti‐inflammatory multipotent MSCs with potential future clinical applications. STEM CELLS 2011;29:251–262
Lineage-specific differentiation potential varies among different human pluripotent stem cell (hPSC) lines, becoming therefore highly desirable to prospectively know which hPSC lines exhibit the ...highest differentiation potential for a certain lineage. We have compared the hematopoietic potential of 14 human embryonic stem cell (hESC)/induced pluripotent stem cell (iPSC) lines. The emergence of hemogenic progenitors, primitive and mature blood cells, and colony-forming unit (CFU) potential was analyzed at different time points. Significant differences in the propensity to differentiate toward blood were observed among hPSCs: some hPSCs exhibited good blood differentiation potential, whereas others barely displayed blood-differentiation capacity. Correlation studies revealed that the CFU potential robustly correlates with hemogenic progenitors and primitive but not mature blood cells. Developmental progression of mesoendodermal and hematopoietic transcription factors expression revealed no correlation with either hematopoietic initiation or maturation efficiency. Microarray studies showed distinct gene expression profile between hPSCs with good versus poor hematopoietic potential. Although neuroectoderm-associated genes were downregulated in hPSCs prone to hematopoietic differentiation many members of the Nodal/Activin signaling were upregulated, suggesting that this signaling predicts those hPSC lines with good blood-differentiation potential. The association between Nodal/Activin signaling and the hematopoietic differentiation potential was confirmed using loss- and gain-of-function functional assays. Our data reinforce the value of prospective comparative studies aimed at determining the lineage-specific differentiation potential among different hPSCs and indicate that Nodal/Activin signaling seems to predict those hPSC lines prone to hematopoietic specification.
Sarcomas have been modeled in mice by the expression of specific fusion genes in mesenchymal stem cells (MSC), supporting the concept that MSCs might be the target initiating cell in sarcoma. In this ...study, we evaluated the potential oncogenic effects of p53 and/or retinoblastoma (Rb) deficiency in MSC transformation and sarcomagenesis. We derived wild-type, p53(-/-), Rb(-/-), and p53(-/-)Rb(-/-) MSC cultures and fully characterized their in vitro growth properties and in vivo tumorigenesis capabilities. In contrast with wild-type MSCs, Rb(-/-), p53(-/-), and p53(-/-)Rb(-/-) MSCs underwent in vitro transformation and showed severe alterations in culture homeostasis. More importantly, p53(-/-) and p53(-/-)Rb(-/-) MSCs, but not Rb(-/-) MSCs, were capable of tumor development in vivo after injection into immunodeficient mice. p53(-/-) or p53(-/-)Rb(-/-) MSCs originated leiomyosarcoma-like tumors, linking this type of smooth muscle sarcoma to p53 deficiency in fat tissue-derived MSCs. Sca1+ and Sca1 low/- cell populations isolated from ex vivo-established, transformed MSC lines from p53(-/-)Rb(-/-) tumors showed identical sarcomagenesis potential, with 100% tumor penetrance and identical latency, tumor weight, and histologic profile. Our findings define the differential roles of p53 and Rb in MSC transformation and offer proof-of-principle that MSCs could provide useful tools to dissect the sarcoma pathogenesis.
Rheumatoid arthritis (RA) is a chronic inflammatory disease of autoimmune origin with many associated genetic traits, including genes related to the control of inflammation. The A20 protein, encoded ...by the
TNFAIP3
gene, is a negative regulator of NF-kB mediated inflammation. Several single nucleotide variants (SNVs) of
TNFAIP3
are associated with susceptibility to RA in different ethnic groups, none of which has been evaluated in Mexican patients.
Objective.
To examine the possible association of eight
TNFAIP3
SNVs in Mexican patients with RA.
Materials
. We studied 471 patients with RA and 500 controls, as well as eight
TNFAIP3
SNVs: including, rs10499194C/T, rs6920220G/A, and rs2230926T/G, which have been associated with RA in European or Asian patients, in addition to rs373421182G/C, rs139054966T/G, rs5029924C/T, rs59693083A/G and rs61593413T/A, not previously examined in RA. All SNVs were evaluated by means of an allelic discrimination assay using TaqMan probes.
Results.
The allelic and genotypic frequencies of all SNVs examined were similar between cases and controls, and none of them was associated with RA under the allelic, codominant, dominant, and recessive models, as well as in haplotype combinations.
Conclusion.
Our data indicate that
TNFAIP3
SNVs evaluated herein are not risk factors for RA in Mexican subjects.
Acute lymphoblastic leukemia (ALL) is a malignancy with high heterogeneity in its biological features and treatments. Although the overall survival (OS) of patients with ALL has recently improved ...considerably, owing to the application of conventional chemo-therapeutic agents, approximately 20% of the pediatric cases and 40-50% of the adult patients relapse during and after the treatment period. The potential mechanisms that cause relapse involve clonal evolution, innate and acquired chemoresistance, and the ability of ALL cells to escape the immune-suppressive tumor response. Currently, immunotherapy in combination with conventional treatment is used to enhance the immune response against tumor cells, thereby significantly improving the OS in patients with ALL. Therefore, understanding the mechanisms of immune evasion by leukemia cells could be useful for developing novel therapeutic strategies.
Objective
The aim of this study was to examine the association of three
TNFSF4
single nucleotide variants (SNVs) with systemic lupus erythematosus (SLE) susceptibility in Mexican patients.
Methods
...Genotypes of the
TNFSF4
rs1234315T/C, rs2205960G/T, and rs704840T/G SNVs were determined using a TaqMan assay. In our study, we included 395 patients with SLE and 500 controls.
Results
Our information shows a significant difference in the allelic and genotypic frequency of the three
TNFSF4
SNVs between cases and controls. Thus, our data showed an association between
TNFSF4
rs1234315T/C (T vs. C, OR 1.40,
p
= 0.00087), rs2205960G/T (G vs. T, OR 1.32,
p
= 0.0037), and rs704840T/G (T vs. G, OR 1.41,
p
= 0.0003) and SLE susceptibility in Mexican subjects. Besides, we conducted a meta-analysis to determine the role of
TNFSF4
rs2205960G/T and SLE susceptibility; our results showed that this variant is a risk factor for SLE in Latin Americans and Asians.
Conclusion
Our results show that
TNFSF4
rs1234315T/C, rs2205960G/T, and rs704840T/G are risk factors to SLE in Mexicans. This is the first study to document an association between
TNFSF4
rs704840T/G and SLE in a Latin American population. In addition, our meta-analysis showed that
TNFSF4
rs2205960G/T is a risk factor for Asians and Latin Americans.
Key Point
• The TNFSF4 rs1234315T/C, rs2205960G/T, and rs704849T/G SNVs are risk factors to SLE in patients from Mexico.
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