Adoptive transfer of the hematopoietic system of trisomic mice with limited life span: Stem cells from six different trisomies are capable of survival

1991 ◽  
Vol 12 (6) ◽  
pp. 415-422 ◽  
Author(s):  
Eberhard W. Herbst ◽  
Heinz Winking
2018 ◽  
Vol 64 (4) ◽  
pp. 522-527
Author(s):  
Aleksey Shutko ◽  
Viktor Mus

Individual parameters of circulating hemopoietic stem cells (HSC) lymphoid origin were measured by cytofluorometry before treatment of patients with metastatic non-small cell lung cancer and were retrospectively compared with individual life span's (LS). The possibility of poor prognosis of treatment's results (LS


1999 ◽  
Vol 19 (6) ◽  
pp. 4093-4100 ◽  
Author(s):  
Odile Begel ◽  
Jocelyne Boulay ◽  
Beatrice Albert ◽  
Eric Dufour ◽  
Annie Sainsard-Chanet

ABSTRACT Podospora anserina is a filamentous fungus with a limited life span. It expresses a degenerative syndrome called senescence, which is always associated with the accumulation of circular molecules (senDNAs) containing specific regions of the mitochondrial chromosome. A mobile group II intron (α) has been thought to play a prominent role in this syndrome. Intron α is the first intron of the cytochrome c oxidase subunit I gene (COX1). Mitochondrial mutants that escape the senescence process are missing this intron, as well as the first exon of theCOX1 gene. We describe here the first mutant of P. anserina that has the α sequence precisely deleted and whose cytochrome c oxidase activity is identical to that of wild-type cells. The integration site of the intron is slightly modified, and this change prevents efficient homing of intron α. We show here that this mutant displays a senescence syndrome similar to that of the wild type and that its life span is increased about twofold. The introduction of a related group II intron into the mitochondrial genome of the mutant does not restore the wild-type life span. These data clearly demonstrate that intron α is not the specific senescence factor but rather an accelerator or amplifier of the senescence process. They emphasize the role that intron α plays in the instability of the mitochondrial chromosome and the link between this instability and longevity. Our results strongly support the idea that in Podospora, “immortality” can be acquired not by the absence of intron α but rather by the lack of active cytochromec oxidase.


Psychiatry ◽  
1961 ◽  
Vol 24 (4) ◽  
pp. 318-323 ◽  
Author(s):  
Lawrence LeShan ◽  
Eda LeShan
Keyword(s):  

2020 ◽  
Author(s):  
Kristina Ames ◽  
Imit Kaur ◽  
Yang Shi ◽  
Meng Tong ◽  
Taneisha Sinclair ◽  
...  

AbstractHematopoietic stem cells (HSCs) maintain the blood system through a delicate equilibrium between self-renewal and differentiation. Most hematopoietic growth factors and cytokines signal through phosphoinositide 3-kinase (PI3K) via three Class IA catalytic PI3K isoforms (P110α, β, and δ), encoded by Pik3ca, Pik3cb, and Pik3cd, respectively. The PI3K/AKT pathway is commonly activated in acute myeloid leukemia (AML), and PI3K is a common therapeutic target in cancer. However, it is not known whether PI3K is required for HSC differentiation or self-renewal. We previously demonstrated that individual PI3K isoforms are dispensable in HSCs1,2. To determine the redundant roles of PI3K isoforms in HSCs, we generated a triple knockout (TKO) mouse model with deletion of all three Class IA PI3K isoforms in the hematopoietic system. Surprisingly, we observed significant expansion of TKO HSCs after transplantation, with decreased differentiation capacity and impaired multilineage repopulation. Additionally, the bone marrow of TKO mice exhibited myelodysplastic features with chromosomal abnormalities. Interestingly, we found that macroautophagy (thereafter autophagy) is impaired in TKO HSCs, and that pharmacologic induction of autophagy improves their differentiation. Therefore, we have uncovered important roles for PI3K in autophagy regulation in HSCs to maintain the balance between self-renewal and differentiation.


Science ◽  
2002 ◽  
Vol 295 (5554) ◽  
pp. 502-505 ◽  
Author(s):  
N. Arantes-Oliveira

Blood ◽  
2004 ◽  
Vol 104 (12) ◽  
pp. 3565-3572 ◽  
Author(s):  
Weili Sun ◽  
James R. Downing

The AML1/CBFβ transcriptional complex is essential for the formation of definitive hematopoietic stem cells (HSCs). Moreover, development of the hematopoietic system is exquisitely sensitive to the level of this complex. To investigate the effect of AML1 dosage on adult hematopoiesis, we compared the hematopoietic systems of AML1+/– and AML1+/+ mice. Surprisingly, loss of a single AML1 allele resulted in a 50% reduction in long-term repopulating hematopoietic stem cells (LTR-HSCs). This decrease did not, however, extend to the next level of hematopoietic differentiation. Instead, AML1+/– mice had an increase in multilineage progenitors, an expansion that resulted in enhanced engraftment following transplantation. The expanded pool of AML1+/– progenitors remained responsive to homeostatic mechanisms and thus the number of mature cells in most lineages remained within normal limits. Two notable exceptions were a decrease in CD4+ T cells, leading to an inversion of the CD4+ to CD8+ T-cell ratio and a decrease in circulating platelets. These data demonstrate a dosage-dependent role for AML1/CBFβ in regulating the quantity of HSCs and their downstream committed progenitors, as well as a more restricted role in T cells and platelets. The latter defect mimics one of the key abnormalities in human patients with the familial platelet disorder resulting from AML1 haploinsufficiency.


Author(s):  
Anthony Parton

An abstract and non-objective style of painting, Rayism ("Luchizm") was pioneered by the Russian artist Mikhail Larionov in early 1912. The style represented the first theoretically coherent and practically consistent response on the part of the Russian avant-garde to the challenges of French Cubism and Italian Futurism. In divorcing art from figuration and in its emphasis on the purely formal qualities of painting, Rayism prepared the way for the development of both Suprematism and Constructivism. Larionov’s innovative style was practiced chiefly by those artists in his immediate orbit: painters such as Natalia Goncharova, Alexander Shevchenko, and Mikhail Le-Dantiyu, who belonged to the Donkey’s Tail and Target group. While Rayism had a limited life-span in Russia, being overtaken by Suprematism in 1915, Larionov and Goncharova continued to practice the style throughout their careers, executing Rayist paintings right up to the 1950s. In its earliest phase, known as "Realistic Rayism" ("Realistichesky luchizm"), the style proceeded from Larionov’s interest in optics and Impressionist color theory and specifically from the idea that the color, contour, and form of our world is defined by rays of light reflected from all material objects. According to Larionov’s booklet Rayism (Luchizm) of 1912, his initial aim was to explore the nature of visual perception as it exists before the brain converts what we see into a comprehensible form.


Sign in / Sign up

Export Citation Format

Share Document