004.Control of skeletal muscle cell proliferation and differentiation

2005 ◽  
Vol 17 (9) ◽  
pp. 63
Author(s):  
M. Grounds

Skeletal muscle is formed by mononucleated precursor cells (myoblasts) that cease cell proliferation to start differentiation; this results in fusion between the myoblasts to form multinucleated cells (myotubes) that continue to differentiate (and fuse with more muscle cells) and mature into myofibres. Myogenesis has been widely used as a model to study in vitro factors controlling cell proliferation and differentiation. Condition in vitro may not reflect what happens in the more complex in vivo environment. Some of the key issues are what activates quiescent myoblasts in mature skeletal muscle in vivo, and what controls the switch between proliferation and differentiation? The role of the matrix, and molecules such as MyoD, p53, NFAT and IGF-1 will be considered.

2018 ◽  
Vol 115 (26) ◽  
pp. 6786-6791 ◽  
Author(s):  
Jiaxi Wu ◽  
Huaizhu Wu ◽  
Jinping An ◽  
Christie M. Ballantyne ◽  
Jason G. Cyster

CD11c, also known as integrin alpha X, is the most widely used defining marker for dendritic cells (DCs). CD11c can bind complement iC3b and mediate phagocytosis in vitro, for which it is also referred to as complement receptor 4. However, the functions of this prominent marker protein in DCs, especially in vivo, remain poorly defined. Here, in the process of studying DC activation and immune responses induced by cells lacking self-CD47, we found that DC capture of CD47-deficient cells and DC activation was dependent on the integrin-signaling adaptor Talin1. Specifically, CD11c and its partner Itgb2 were required for DC capture of CD47-deficient cells. CD11b was not necessary for this process but could partially compensate in the absence of CD11c. Mice with DCs lacking Talin1, Itgb2, or CD11c were defective in supporting T-cell proliferation and differentiation induced by CD47-deficient cell associated antigen. These findings establish a critical role for CD11c in DC antigen uptake and activation in vivo. They may also contribute to understanding the functional mechanism of CD47-blockade therapies.


2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 97-97
Author(s):  
Zong-ming Zhang ◽  
Chun-qi Gao ◽  
Hui-chao Yan ◽  
Xiu-qi Wang

Abstract Wnt/β-catenin plays a crucial role in skeletal muscle growth, but its specific mechanism still unclear. In this study, due to the distinct role of lysine in pig industry, we provided it as an entry point to investigate the role of Wnt/β-catenin in governing skeletal muscle growth. Firstly, total 18 weaned piglets were divided into three groups: control group, lysine deficiency group and lysine re-supplementation group (lysine levels added from 0.83% to 1.31% at 14 d). After 28 d experiment, all pigs were slaughtered to measure the change of Wnt/β-catenin in skeletal muscle. Secondly, satellite cell (SC) was isolated and cultured with Wnt activator, such as Wnt3a and WRN (Wnt3a, R-spondin1, Noggin) after lysine deficiency for 48 h to investigate cell proliferation and differentiation ability and the level of Wnt/β-catenin in different conditions. The results showed that compared with the control group, lysine deficiency significantly reduced longissimus dorsi muscle weight and Pax7 positive SC, and inhibited Wnt/β-catenin (P < 0.05). Fortunately, these restrictions were rescued to the control levels by lysine re-supplementation (P > 0.05). Meanwhile, compared with the lysine deficiency group, the MTT and western blotting assay showed cell proliferation ability was significantly increased with re-activated Wnt/β-catenin by re-supplemented lysine, Wnt3a or WRN (P < 0.05), respectively. Moreover, under the condition of cell differentiation, compared with the control group, cell fusion index was significantly decreased in the lysine deficiency group (P < 0.05), whereas it was significantly increased with lysine re-supplementation group, Wnt3a or WRN respective supplementation group in comparison with the lysine deficiency group (P < 0.05). In addition, compared with the lysine deficiency group, the protein levels of myogenic regulatory factors and Wnt/β-catenin pathway were also re-activated by re-supplemented lysine, Wnt3a or WRN (P < 0.05). Collectively, we found Wnt/β-catenin activation is required for porcine SC proliferation and differentiation to promote skeletal muscle growth.


2009 ◽  
Vol 203 (2) ◽  
pp. 231-240 ◽  
Author(s):  
Tamiki Hikake ◽  
Shinji Hayashi ◽  
Taisen Iguchi ◽  
Tomomi Sato

IGF1 knockout (IGF1KO) mice show a reduced number of prolactin (PRL) producing cells (PRL cells); however, the role of IGF1 in PRL cell proliferation and differentiation in immature mice is unclear. In this study, ontogenic changes in the percentages of PRL cells, GH producing cells (GH cells), and 5-bromo-2′-deoxyuridine (BrdU)-labeled cells in the anterior pituitary of male IGF1KO mice during the postnatal period were investigated. The percentage of PRL cells in IGF1KO mice was significantly lower at day 20 compared with that in wild-type (WT) mice, while GH cells in IGF1KO mice were significantly increased from day 10. From days 5 to 20, the percentage of BrdU-labeled cells in WT and IGF1KO mice was similar. PRL cells and GH cells are thought to originate from the same progenitor cells, therefore, PRL cells in IGF1KO mice are not able to differentiate because progenitor cells have already committed to be GH cells. However, IGF1, 17β-estradiol (E2), epidermal growth factor (EGF), or IGF1 plus E2 treatments increased the PRL cell number in the pituitaries in vitro of 10-day-old WT and IGF1KO mice. This fact suggests that these factors are involved in PRL cell proliferation and differentiation. In addition, the increase of PRL cells in IGF1KO mice stimulated by E2 or EGF was less than that of WT mice. Thus, IGF1 plays a crucial role in PRL cell proliferation and differentiation in mouse pituitaries by regulating the differentiation of progenitor cells and mediating the actions of E2 and EGF.


1998 ◽  
Vol 76 (6) ◽  
pp. 957-969 ◽  
Author(s):  
Jean-Noël Freund ◽  
Claire Domon-Dell ◽  
Michèle Kedinger ◽  
Isabelle Duluc

The past years have witnessed an increasing number of reports relative to homeobox genes in endoderm-derived tissues. In this review, we focus on the caudal-related Cdx-1 and Cdx-2 homeobox genes to give an overview of the in vivo, in vitro, and ex vivo approaches that emphasize their primary role in intestinal development and in the control of intestinal cell proliferation, differentiation, and identity. The participation of these genes in colon tumorigenesis and their identification as important actors of the oncogenic process are also discussed.Key words: caudal, epithelial cell proliferation and differentiation, cancer.


1992 ◽  
Vol 263 (2) ◽  
pp. C343-C347 ◽  
Author(s):  
V. Quemener ◽  
Y. Blanchard ◽  
D. Lescoat ◽  
R. Havouis ◽  
J. P. Moulinoux

Polyamines (PA), polycations present in all mammalian cells, are essential for cell proliferation and differentiation. In vitro, PA are known to bind to DNA with a high affinity. In vivo, the intimate association of endogenous PA with highly condensed chromatin has been reported. During spermatogenesis, when processes of cell proliferation and differentiation take place, the potential role of polyamines has not been studied in depth. We report here the PA levels measured in human spermatogenic cell nuclei at different stages of differentiation. Cell populations (spermatocytes and round, elongating, or elongated spermatids) were obtained after submitting human testes to a trypsin-deoxyribonuclease digestion, then to a centrifugal elutriation and Percoll gradient centrifugation. A significant and progressive nuclear spermine level decrease was observed from primary spermatocytes to elongated spermatids. This release of spermine from nuclei was concomitant with three major events in mammalian spermiogenesis: the reduction of DNA transcription activity, the replacement of histone proteins by protamines, and the compaction of chromatin. This is the first report arguing a release of nuclear spermine during an in vivo physiological cell differentiation process.


Blood ◽  
2021 ◽  
Author(s):  
Andrea Brendolan ◽  
Vincenzo Russo

Cholesterol is a vital lipid for cellular functions. It is necessary for membrane biogenesis, cell proliferation and differentiation. In addition to maintaining cell integrity and permeability, increasing evidence indicates a strict link between cholesterol homeostasis, inflammation and haematological tumors. This makes cholesterol homeostasis an optimal therapeutic target for hematopoietic malignancies. Manipulating cholesterol homeostasis either interfering with its synthesis or activating the reverse cholesterol transport via the engagement of liver X receptors (LXRs), affects the integrity of tumor cells both in vitro and in vivo. Cholesterol homeostasis has also been manipulated to restore antitumor immune responses in preclinical models. These observations have prompted clinical trials in acute myeloid leukemia (AML) to test the combination of chemotherapy with drugs interfering with cholesterol synthesis, i.e. statins. We review the role of cholesterol homeostasis in hematopoietic malignancies, as well as in cells of the tumor microenvironment, and discuss the potential use of lipid modulators for therapeutic purposes.


1998 ◽  
Vol 333 (3) ◽  
pp. 645-654 ◽  
Author(s):  
Judit GARRIGA ◽  
Ana LIMÓN ◽  
Xavier MAYOL ◽  
Sushil G. RANE ◽  
Jeffrey H. ALBRECHT ◽  
...  

In the present study we have analysed the regulation of pocket protein expression and post-transcriptional modifications on cell proliferation and differentiation, both in vivo and in vitro. There are marked changes in pocket protein levels during these transitions, the most striking differences being observed between p130 and p107. The mechanisms responsible for regulating pocket protein levels seem to be dependent on both cell type and pocket protein, in addition to their dependence on the cell growth status. Changes in retinoblastoma protein and p107 levels are independent of their state of phosphorylation. However, whereas p130 phosphorylation to forms characteristic of quiescent/differentiated cells results in the accumulation of p130 protein, phosphorylation of p130 to one or more forms characteristic of cycling cells is accompanied by down-regulation of its protein levels. We also show here that the phosphorylation status and protein levels of p130 and p107 are regulated in vivo as in cultured cells. In vivo, changes in p130 forms are correlated with changes in E2F complexes. Moreover, the modulation of p130 and p107 status during cell differentiation in vitro is consistent with the patterns of protein expression and phosphorylation status found in mouse tissues. Thus in addition to the direct disruption of pocket protein/E2F complexes induced by cyclin/cyclin-dependent kinase, the results we report here indicate that the differential modulation of pocket protein levels constitutes a major mechanism that regulates the pool of each pocket protein that is accessible to E2F and/or other transcription factors.


2016 ◽  
Vol 49 (1) ◽  
Author(s):  
Soundharrajan Ilavenil ◽  
Da Hye Kim ◽  
Mayakrishnan Vijayakumar ◽  
Srisesharam Srigopalram ◽  
Sang Gun Roh ◽  
...  

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