Hematopoietic Specific GATA-1-Improved Cre Mouse for Erythroid-Specific Gene Modification.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1291-1291
Author(s):  
Donghoon Yoon ◽  
Bumjun Kim ◽  
Myunghi Kwon ◽  
Josef T. Prchal
Keyword(s):  
Bone Marrow ◽  
Transgenic Mouse ◽  
Erythropoietin Receptor ◽  
Specific Gene ◽  
Hematopoietic Tissue ◽  
Knock Out ◽  
Tissue Sections ◽  
Lacz Staining ◽  
Splenic Cells ◽  
Beta Galactosidase

Abstract Animal models of erythropoiesis related genes have been limited by the fact that some of these genes have non-erythroid expression and other functions in addition to erythropoiesis and thus their knock-out may be embryonic lethal. Tissue specific knock-out or knock-in mice models employing GATA-1-Cre and other constructs showed that these promoters are also active in non-hematopoietic tissues, i.e. GATA-1 has activity in early embryonic development and in neuronal tissue. Suzuki et al (Blood, 2002, 100; 2279) isolated the GATA-1 locus hematopoietic regulatory domain (GATA-1-HRD) and demonstrated that the expression of a transgene under its control is limited to the hematopoietic tissue. We generated a transgenic mouse expressing an improved Cre (iCre) under GATA-1-HRD promoter control. This mouse was crossbred with ROSA 26 mouse and the progeny was examined for tissue specificity of iCre expression using beta-galactosidase staining. Brain, spleen, kidney, heart, thymus, liver, lung and ovary were examined for whole organ LacZ staining. All tested organs were negative except kidney and spleen where some positivity was observed. Subsequently, we prepared tissue sections from kidney, spleen and bone marrow and stained with LacZ and anti-beta-galactosidase antibody. Only the bone marrow EpoR expressing cells were positive; the kidney and the spleen cells were negative. Although Suzuki et al previously showed expression of the GATA-1-HRD driven erythropoietin receptor in spleen using RT-PCR, we were not able to find iCre expression in the splenic cells using these approaches. We demonstrate that our transgenic mouse (GATA-1-HRD-iCre) showed a restricted iCre expression in hematopoietic tissue that differs from previous studies of other hematopoiesis specific cre mouse. We conclude that this mouse model should be useful in studies of function of erythroid specific genes.

Tie-2 Activation Is Required for Regeneration of Marrow Vasculature, Supporting Hematopoietic Reconstitution.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1297-1297
Author(s):  
Hans-Georg Kopp ◽  
Scott T. Avecilla ◽  
Rafael Tejada ◽  
Ronald G. Crystal ◽  
Neil R. Hackett ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Steady State ◽  
Chimeric Mice ◽  
Hematopoietic Progenitor ◽  
Platelet Recovery ◽  
Decoy Receptor ◽  
Hematopoietic Reconstitution ◽  
Lacz Staining ◽  
Functional Regeneration ◽  
Beta Galactosidase

Abstract Accumulating evidence from our lab (Nature Med.2004; 10(1): 64–71) and others have shown that myelosuppression not only results in apoptosis of the hematopoietic cells but also in regression of bone marrow (BM) sinusoidal vessels. Remarkably, we have shown that restoration of hematopoiesis is dependent on the regeneration of BM sinusoidal neo-vessels. However, the mechanism whereby vascular reconstitution is regulated is unknown. Because Tie2/Angiopoietins are critical in the remodeling of neo-vessels, we hypothesized that activation of Tie2 plays a role in regeneration of sinusoidal neo-vessels and restoration of hematopoiesis. To this end, we took advantage of transgenic mice where the Tie2 promoter drives the expression of beta-galactosidase (LacZ) in order to follow the expression of Tie2 in hematopoietic progenitor cells after myelosuppression. Under steady-state conditions, only few LacZ/Tie-2+ cells were localized in the endosteal/osteoblastic region, without any expression within the BM sinusoidal neo-vessels. However, after a myelosuppressive dose of 5-Fluorouracil (5-FU) there was a robust expression of Tie2 expression in the regenerating BM sinusoidal neo-vessels. The expression of Tie2 on the regenerating neo-vasculature reached a maximum at day 10 and reverted back to steady-state by day 20 post 5-FU, the time in which the majority of the neo-vessels were functionally assembled. Blocking angiopoietin/Tie2 signaling with the soluble decoy-receptor, Tie2Fc, after 5-FU inhibited platelet recovery as well as vascular reconstitution. There was a paradoxical accumulation of megakaryocytes in the bone-marrow during the prolonged thrombocytopenic phase, which we have previously shown to be due to vascular niche disruption and inability of megakaryocytes to release platelets. To examine the possibility that Tie2+ progenitors can reconstitute BM sinusoids in the recipient mice, lethally irradiated wildtype mice were transplanted with the BM of Tie2-lacZ knock-in mice. After full recovery, the chimeric mice were challenged with a myelosuppressive dose of 5-FU and Tie2+ neo-vessels were detected histologically on day 5, 10, and 14 by LacZ staining. Remarkably, the reconstituted bone marrow showed the presence of Tie2+ vessels, which unambiguously demonstrates the contribution of donor-derived endothelial progenitors to the reconstitution of the regressed vasculature. Together, our data support the hypothesis that Tie2/angiopoietin signaling is essential for functional regeneration of BM sinusoidal neo-vessels and contributes to the reconstitution of hematopoiesis, specifically to thrombopoiesis. In addition, the use of Tie2-LacZ mice provides an invaluable model to quantify the number of regenerating BM neo-vessels. Angiopoietins may be used in clinical setting in conjunction with other lineage specific cytokines to enhance hematopoiesis after myelosuppression.

scholarly journals Knock-in and precise nucleotide substitution using near-PAMless engineered Cas9 variants in Dictyostelium discoideum

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuu Asano ◽  
Kensuke Yamashita ◽  
Aoi Hasegawa ◽  
Takanori Ogasawara ◽  
Hoshie Iriki ◽  
...  
Keyword(s):  
Genome Editing ◽  
Dictyostelium Discoideum ◽  
Streptococcus Pyogenes ◽  
Nucleotide Substitution ◽  
Point Mutations ◽  
Targeted Mutagenesis ◽  
Single Amino Acid ◽  
Specific Gene ◽  
Knock Out ◽  
Protospacer Adjacent Motif

AbstractThe powerful genome editing tool Streptococcus pyogenes Cas9 (SpCas9) requires the trinucleotide NGG as a protospacer adjacent motif (PAM). The PAM requirement is limitation for precise genome editing such as single amino-acid substitutions and knock-ins at specific genomic loci since it occurs in narrow editing window. Recently, SpCas9 variants (i.e., xCas9 3.7, SpCas9-NG, and SpRY) were developed that recognise the NG dinucleotide or almost any other PAM sequences in human cell lines. In this study, we evaluated these variants in Dictyostelium discoideum. In the context of targeted mutagenesis at an NG PAM site, we found that SpCas9-NG and SpRY were more efficient than xCas9 3.7. In the context of NA, NT, NG, and NC PAM sites, the editing efficiency of SpRY was approximately 60% at NR (R = A and G) but less than 22% at NY (Y = T and C). We successfully used SpRY to generate knock-ins at specific gene loci using donor DNA flanked by 60 bp homology arms. In addition, we achieved point mutations with efficiencies as high as 97.7%. This work provides tools that will significantly expand the gene loci that can be targeted for knock-out, knock-in, and precise point mutation in D. discoideum.

scholarly journals Melatonin promotes bone marrow mesenchymal stem cell osteogenic differentiation and prevents osteoporosis development through modulating circ_0003865 that sponges miR-3653-3p

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xudong Wang ◽  
Taiqiu Chen ◽  
Zhihuai Deng ◽  
Wenjie Gao ◽  
Tongzhou Liang ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Mesenchymal Stem Cell ◽  
Osteogenic Differentiation ◽  
Luciferase Reporter ◽  
Specific Gene ◽  
Biological Processes ◽  
Alizarin Red ◽  
Qrt Pcr ◽  
Dual Luciferase Reporter Assay

Abstract Background Little is known about the implications of circRNAs in the effects of melatonin (MEL) on bone marrow mesenchymal stem cell (BMSC) osteogenic differentiation and osteoporosis (OP) progression. The aim of our study was to investigate circRNAs in MEL-regulated BMSC differentiation and OP progression. Methods BMSC osteogenic differentiation was measured by qRT-PCR, western blot (WB), Alizarin Red, and alkaline phosphatase (ALP) staining. Differential circRNA and mRNA profiles of BMSCs treated by MEL were characterized by deep sequencing, followed by validation using RT-PCR, Sanger sequencing, and qRT-PCR. Silencing and overexpression of circ_0003865 were conducted for functional investigations. The sponged microRNAs and targeted mRNAs were predicted by bioinformatics and validated by qRT-PCR, RNA pull-down, and dual-luciferase reporter assay. The function of miR-3653-3p and circ_0003865/miR-3653-3p/growth arrest-specific gene 1 (GAS1) cascade was validated for the osteogenic differentiation of BMSCs by CCK-8, qRT-PCR, WB, Alizarin Red, and ALP staining. The effects of circ_0003865 on OP development were tested in murine OP model. Results MEL promoted osteogenic differentiation of BMSCs. RNA sequencing revealed significant alterations in circRNA and mRNA profiles associated with multiple biological processes and signaling pathways. Circ_0003865 expression in BMSCs was significantly decreased by MEL treatment. Silencing of circ_0003865 had no effect on proliferation while promoted osteogenic differentiation of BMSCs. Overexpression of circ_0003865 abrogated the promotion of BMSC osteogenic differentiation induced by MEL, but proliferation of BMSCs induced by MEL had no change whether circ_0003865 was overexpression or not. Furthermore, circ_0003865 sponged miR-3653-3p to promote GAS1 expression in BMSCs. BMSC osteogenic differentiation was enhanced by miR-3653-3p overexpression while BMSC proliferation was not affected. By contrast, miR-3653-3p silencing mitigated the promoted BMSC osteogenic differentiation caused by circ_0003865 silencing, but had no effect on proliferation. Finally, circ_0003865 silencing repressed OP development in mouse model. Conclusion MEL promotes BMSC osteogenic differentiation and inhibits OP pathogenesis by suppressing the expression of circ_0003865, which regulates GAS1 gene expression via sponging miR-3653-3p.

scholarly journals Population kinetics of rat peripheral B cells.

1988 ◽  
Vol 167 (3) ◽  
pp. 805-816 ◽  
Author(s):  
D Gray
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
B Cell ◽  
Population Kinetics ◽  
Tissue Sections ◽  
Cell Pool ◽  
Cell Life ◽  
Dividing Cells ◽  
Kinetics Of ◽  
Selective Effects

Currently available estimates of B cell life span vary from 4 d to 6 wk. The discrepancy may have arisen out of the selective effects of stress and drug cytotoxicity on short-lived populations. In this report, bromodeoxyuridine (BUdR), a drug that incorporates into the DNA of dividing cells, has been fed to rats in their drinking water, eliminating stressful injection procedures. Labeled cells in the recirculating B cell pool are identified in tissue sections using an mAb to BUdR. BUdR is shown to have no cytostatic effects at the dose used. Over a 5-d period of infusion, only 20% of the peripheral recirculating pool incorporate label (approximately 4% per day); labeling over various periods indicates that the peripheral B cell pool turns over in approximately 4 wk. To distinguish between turnover due to incorporation of new B cells into the peripheral pool and division of antigen-activated B cells rats underwent two consecutive periods of labeling, first with [3H]thymidine for 5 d and then with BUdR for a further 5 d. Virgin B cells newly derived from dividing precursors in the bone marrow do not continue to proliferate in the periphery, while activated cells undergo several rounds of division during both labeling periods. The results indicate that 3-4% of the peripheral pool is replaced by new B cells each day, while 0.3-0.6% become part of activated clones every day. Assuming that the peripheral pool of the rat contains 10(9) B cells, then 3-4 X 10(7) new B cells become stably incorporated per day. This represents approximately 10% of the putative output of the bone marrow.

Murine pluripotent hematopoietic progenitors constitutively expressing a normal erythropoietin receptor proliferate in response to erythropoietin without preferential erythroid cell differentiation

1994 ◽  
Vol 14 (7) ◽  
pp. 4834-4842
Author(s):  
A Dubart ◽  
F Feger ◽  
C Lacout ◽  
F Goncalves ◽  
W Vainchenker ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Progenitor Cells ◽  
Bone Marrow Cells ◽  
Erythropoietin Receptor ◽  
Erythroid Cell ◽  
Major Influence ◽  
Proliferative Potential ◽  
Steel Factor ◽  
Interleukin 3 ◽  
Marrow Cells

Erythropoietin (EPO) is a prime regulator of the growth and differentiation of erythroid blood cells. The EPO receptor (EPO-R) is expressed in late erythroid progenitors (mature BFU-E and CFU-E), and EPO induces proliferation and differentiation of these cells. By introducing, with a retroviral vector, a normal EPO-R cDNA into murine adult bone marrow cells, we showed that EPO is also able to induce proliferation in pluripotent progenitor cells. After 7 days of coculture with virus-producing cells, bone marrow cells were plated in methylcellulose culture in the presence of EPO, interleukin-3, or Steel factor alone or in combination. In the presence of EPO alone, EPO-R virus-infected bone marrow cells gave rise to mixed colonies comprising erythrocytes, granulocytes, macrophages and megakaryocytes. The addition of interleukin-3 or Steel factor to methylcellulose cultures containing EPO did not significantly modify the number of mixed colonies. The cells which generate these mixed colonies have a high proliferative potential as shown by the size and the ability of the mixed colonies to give rise to secondary colonies. Thus, it appears that EPO has the same effect on EPO-R-expressing multipotent cell proliferation as would a combination of several growth factors. Finally, our results demonstrate that inducing pluripotent progenitor cells to proliferate via the EPO signaling pathway has no major influence on their commitment.

scholarly journals Fos-related antigen-1 transgenic mouse as a model for systemic sclerosis: A potential role of M2 polarization

2019 ◽  
Vol 4 (2) ◽  
pp. 137-148
Author(s):  
Hidekata Yasuoka ◽  
Yuen Yu Angela Tam ◽  
Yuka Okazaki ◽  
Yuichi Tamura ◽  
Koichi Matsuo ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Systemic Sclerosis ◽  
Transgenic Mice ◽  
Pressure Gradient ◽  
Transgenic Mouse ◽  
Tricuspid Regurgitation ◽  
Mononuclear Cells ◽  
M2 Macrophages ◽  
Wild Type ◽  
M2 Polarization

Objectives: To investigate the systemic sclerosis–related phenotype in fos-related antigen-1 transgenic mice and its underlying mechanisms. Methods: Lung and skin sections of constitutive fos-related antigen-1 transgenic mice and wild-type mice were examined by tissue staining and immunohistochemistry. The tricuspid regurgitation pressure gradient was measured by transthoracic echocardiography with a Doppler technique. To assess the impact of fos-related antigen-1 expression on macrophage function, bone marrow–derived mononuclear cells were derived from mice that expressed fos-related antigen-1 under the control of doxycycline and wild-type littermates. These bone marrow–derived mononuclear cells were induced to differentiate into macrophages with or without doxycycline, and analyzed for gene and protein expression. Finally, lung explants obtained from systemic sclerosis patients and control donors were subjected to immunohistochemistry. Results: The lungs of fos-related antigen-1 transgenic mice showed excessive fibrosis of the interstitium and thickening of vessel walls, with narrowing lumen, in an age-dependent manner. The tricuspid regurgitation pressure gradient was significantly elevated in fos-related antigen-1 transgenic versus control mice. Increased dermal thickness and the loss of subdermal adipose tissue were also observed in the fos-related antigen-1 transgenic mice. These changes were preceded by a perivascular infiltration of mononuclear cells, predominantly consisting of alternatively activated or M2 macrophages. Overexpressing fos-related antigen-1 in bone marrow–derived mononuclear cell cultures increased the expression of M2-related genes, such as Il10, Alox15, and Arg1. Finally, fos-related antigen-1-expressing M2 macrophages were increased in the lung tissues of systemic sclerosis patients. Conclusions: The fos-related antigen-1 transgenic mouse serves as a genetic model of systemic sclerosis that recapitulates the major vascular and fibrotic manifestations of the lungs and skin in systemic sclerosis patients. M2 polarization mediated by the up-regulation of fos-related antigen-1 may play a critical role in the development of systemic sclerosis.

scholarly journals Transplantation Induces Profound Changes in the Transcriptional Asset of Hematopoietic Stem Cells: Identification of Specific Signatures Using Machine Learning Techniques

2020 ◽  
Vol 9 (6) ◽  
pp. 1670
Author(s):  
Daniela Cilloni ◽  
Jessica Petiti ◽  
Valentina Campia ◽  
Marina Podestà ◽  
Margherita Squillario ◽  
...  
Keyword(s):  
Machine Learning ◽  
Bone Marrow ◽  
Cord Blood ◽  
Umbilical Cord ◽  
Umbilical Cord Blood ◽  
Machine Learning Techniques ◽  
Specific Gene ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Cd34 Cells

During the phase of proliferation needed for hematopoietic reconstitution following transplantation, hematopoietic stem/progenitor cells (HSPC) must express genes involved in stem cell self-renewal. We investigated the expression of genes relevant for self-renewal and expansion of HSPC (operationally defined as CD34+ cells) in steady state and after transplantation. Specifically, we evaluated the expression of ninety-one genes that were analyzed by real-time PCR in CD34+ cells isolated from (i) 12 samples from umbilical cord blood (UCB); (ii) 15 samples from bone marrow healthy donors; (iii) 13 samples from bone marrow after umbilical cord blood transplant (UCBT); and (iv) 29 samples from patients after transplantation with adult hematopoietic cells. The results show that transplanted CD34+ cells from adult cells acquire an asset very different from transplanted CD34+ cells from cord blood. Multivariate machine learning analysis (MMLA) showed that four specific gene signatures can be obtained by comparing the four types of CD34+ cells. In several, but not all cases, transplanted HSPC from UCB overexpress reprogramming genes. However, these remarkable changes do not alter the commitment to hematopoietic lineage. Overall, these results reveal undisclosed aspects of transplantation biology.

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