scholarly journals Skeletal muscle phenotypes initiated by ectopic MyoD in transgenic mouse heart

Development ◽  
1992 ◽  
Vol 114 (4) ◽  
pp. 853-860 ◽  
Author(s):  
J.H. Miner ◽  
J.B. Miller ◽  
B.J. Wold
Keyword(s):  
Skeletal Muscle ◽  
Cultured Cells ◽  
Regulatory Gene ◽  
Cell Lineage ◽  
Cardiac Differentiation ◽  
Mouse Heart ◽  
Mouse Development ◽  
Cellular Environment ◽  
Close Relatives

Forced expression of the myogenic regulatory gene MyoD in many types of cultured cells initiates their conversion into skeletal muscle. It is not known, however, if MyoD expression serves to activate all or part of the skeletal muscle program in vivo during animal development, nor is it known how limiting the influences of cellular environment may be on the regulatory effects of MyoD. To begin to address these issues, we have produced transgenic mice which express MyoD in developing heart, where neither MyoD nor its three close relatives—myogenin, Myf-5, and MRF4/herculin/Myf-6—are normally expressed. The resulting gross phenotype in offspring from multiple, independent transgenic founders includes abnormal heart morphology and ultimately leads to death. At the molecular level, affected hearts exhibit activation of skeletal muscle-specific regulatory as well as structural genes. We conclude that MyoD is able to initiate the program that leads to skeletal muscle differentiation during mouse development, even in the presence of the ongoing cardiac differentiation program. Thus, targeted misexpression of this tissue-specific regulator during mammalian embryogenesis can activate, either directly or indirectly, a diverse set of genes normally restricted to a different cell lineage and a different cellular environment.

scholarly journals T-cell lineage commitment and cytokine responses of thymic progenitors

Blood ◽  
1995 ◽  
Vol 86 (5) ◽  
pp. 1850-1860 ◽  
Author(s):  
TA Moore ◽  
A Zlotnik
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Function ◽  
Cultured Cells ◽  
Critical Role ◽  
Cell Lineage ◽  
Lineage Commitment ◽  
Organ Cultures ◽  
Cell Commitment

The earliest steps of intrathymic differentiation recently have been elucidated. It has been reported that both CD4lo (CD44+ CD25- c-kit+ CD3- CD4lo CD8-) and pro-T cells (CD44+ CD25+ c-kit+ CD3- CD4- CD8-, representing the next step in maturation) exhibit germline T-cell receptor beta and gamma loci, suggesting that neither population is exclusively committed to the T-cell lineage. Several groups have shown that CD4lo cells retain the capacity to generate multiple lymphoid lineages in vivo; however, the lineage commitment status of pro-T cells is unknown. To determine when T-cell lineage commitment occurs, we examined the ability of sorted CD4lo and pro-T cells to generate lymphoid lineage cells in vivo or in fetal thymic organ cultures (FTOCs). When intravenously injected into scid mice, CD4lo cells generated both T and B cells, whereas the progeny of pro-T cells contained T cells exclusively. Fetal thymic organ cultures repopulated with CD4lo cells contained both T and natural killer (NK) cells, whereas cultures repopulated with pro-T cells contained T cells almost exclusively. These observations strongly suggest that T-cell lineage commitment occurs during the transition of CD4lo to pro-T cells. Because it is likely that the thymic microenvironment plays a critical role in T-cell commitment, we compared the responses of CD4lo and pro-T cells to various cytokine combinations in vitro, as well as the ability of the cultured cells to repopulate organ cultures. Cytokine combinations that maintained T-cell repopulation potential for both CD4lo and pro-T cells were found. CD4lo cells proliferated best in response to the combination containing interleukin-1 (IL-1), IL-3, IL- 6, IL-7, and stem cell factor (SCF). Unlike CD4lo cells, pro-T cells were much more dependent upon IL-7 for proliferation and FTOC repopulation. However, combinations of cytokines lacking IL-7 were found that maintained the T-cell repopulating potential of pro-T cells, suggesting that, whereas this cytokine is clearly very important for normal pro-T cell function, it is not an absolute necessity during early T-cell expansion and differentiation.

scholarly journals Loss of the histone chaperone ASF1B reduces female reproductive capacity in mice

Reproduction ◽  
2016 ◽  
Vol 151 (5) ◽  
pp. 477-489 ◽  
Author(s):  
S Messiaen ◽  
J Guiard ◽  
C Aigueperse ◽  
I Fliniaux ◽  
S Tourpin ◽  
...  
Keyword(s):  
Gonad Development ◽  
Cell Lineage ◽  
Reproductive Capacity ◽  
Chromatin Modifications ◽  
Mouse Development ◽  
Differentiation Potential ◽  
Female Mice ◽  
Evolutionarily Conserved ◽  
Meiotic Entry

Abstract Anti-silencing function 1 (ASF1) is an evolutionarily conserved histone H3–H4 chaperone involved in the assembly/disassembly of nucleosome and histone modification. Two paralogous genes, Asf1a and Asf1b, exist in the mouse genome. Asf1a is ubiquitously expressed and its loss causes embryonic lethality. Conversely, Asf1b expression is more restricted and has been less studied. To determine the in vivo function of Asf1b, we generated a Asf1b-deficient mouse line (Asf1bGT(ROSA-βgeo)437) in which expression of the lacZ reporter gene is driven by the Asf1b promoter. Analysis of β-galactosidase activity at early embryonic stages indicated a correlation between Asf1b expression and cell differentiation potential. In the gonads of both male and female, Asf1b expression was specifically detected in the germ cell lineage with a peak expression correlated with meiosis. The viability of Asf1b-null mice suggests that Asf1b is dispensable for mouse development. However, these mice showed reduced reproductive capacity compared with wild-type controls. We present evidence that the timing of meiotic entry and the subsequent gonad development are affected more severely in Asf1b-null female mice than in male mice. In female mice, in addition to subfertility related to altered gamete formation, variable defects compromising the development and/or survival of their offspring were also observed. Altogether, our data indicate the importance of Asf1b expression at the time of meiotic entry, suggesting that chromatin modifications may play a central role in this process.

Hindlimb Muscle Dissection, Permeabilization, and Respirometry v1

2021 ◽  
Author(s):  
Matthew D. Campbell ◽  
David J. Marcinek
Keyword(s):  
Skeletal Muscle ◽  
Muscle Biopsy ◽  
Mitochondrial Respiration ◽  
Gastrocnemius Muscle ◽  
Muscle Fibers ◽  
Mouse Muscle ◽  
Skeletal Muscle Biopsy ◽  
Cellular Environment ◽  
Permeabilized Muscle

The use of permeabilized muscle fibers (PMF) has emerged as a gold standard for assessing skeletal muscle mitochondrial function. PMF provide an intermediate approach between in vivo strategies and isolated mitochondria that allows the mitochondria to be maintained in close to their native morphology in the myofiber while allowing greater control of substrate and inhibitor concentrations. However, like mitochondrial isolation, the primary drawback to PMF is disruption of the cellular environment during the muscle biopsy and preparation. Despite all the benefits of permeabilized muscle fibers in evaluating mitochondrial respiration and dynamics one of the major drawbacks is increased variability introduced during a muscle biopsy as well as intrinsic variation that exists due to sex and age. This study was designed to evaluate how age, sex, and biopsy preparations affect mitochondrial respiration in extensor digitorum longus, soleus, and gastrocnemius muscle of mice. Here we detail a modified approach to skeletal muscle biopsy of the gastrocnemius muscle of mice focused on maintenance of intact fibers that results in greater overall respiration compared to cut fibers. The improved respiration of intact fibers is sex specific as are some of the changes in mitochondrial respiration with age. This study shows the need for standard practices when measuring mitochondrial respiration in permeabilized muscle and provides a protocol to control for variation introduced during a typical mouse muscle biopsy.

scholarly journals Synchrony of sarcomeric movement regulates left ventricular pump function in the in vivo beating mouse heart

2021 ◽  
Vol 153 (11) ◽  
Author(s):  
Fuyu Kobirumaki-Shimozawa ◽  
Togo Shimozawa ◽  
Kotaro Oyama ◽  
Shunsuke Baba ◽  
Jia Li ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Sarcomere Length ◽  
Left Ventricular ◽  
Mouse Heart ◽  
The Novel ◽  
Passive Force ◽  
Pump Function ◽  
Average Value ◽  
Contribution Index

Sarcomeric contraction in cardiomyocytes serves as the basis for the heart’s pump functions. It has generally been considered that in cardiac muscle as well as in skeletal muscle, sarcomeres equally contribute to myofibrillar dynamics in myocytes at varying loads by producing similar levels of active and passive force. In the present study, we expressed α-actinin–AcGFP in Z-disks to analyze dynamic behaviors of sequentially connected individual sarcomeres along a myofibril in a left ventricular (LV) myocyte of the in vivo beating mouse heart. To quantify the magnitude of the contribution of individual sarcomeres to myofibrillar dynamics, we introduced the novel parameter “contribution index” (CI) to measure the synchrony in movements between a sarcomere and a myofibril (from −1 [complete asynchrony] to 1 [complete synchrony]). First, CI varied markedly between sarcomeres, with an average value of ∼0.3 during normal systole. Second, when the movements between adjacent sarcomeres were asynchronous (CI < 0), a sarcomere and the ones next to the adjacent sarcomeres and farther away moved in synchrony (CI > 0) along a myofibril. Third, when difference in LV pressure in diastole and systole (ΔLVP) was lowered to <10 mm Hg, diastolic sarcomere length increased. Under depressed conditions, the movements between adjacent sarcomeres were in marked asynchrony (CI, −0.3 to −0.4), and, as a result, average CI was linearly decreased in association with a decrease in ΔLVP. These findings suggest that in the left ventricle of the in vivo beating mouse heart, (1) sarcomeres heterogeneously contribute to myofibrillar dynamics due to an imbalance of active and passive force between neighboring sarcomeres, (2) the force imbalance is pronounced under depressed conditions coupled with a marked increase in passive force and the ensuing tug-of-war between sarcomeres, and (3) sarcomere synchrony via the distal intersarcomere interaction regulates the heart's pump function in coordination with myofibrillar contractility.

scholarly journals The muscle regulatory gene, Myf-6, has a biphasic pattern of expression during early mouse development.

1991 ◽  
Vol 113 (6) ◽  
pp. 1255-1265 ◽  
Author(s):  
E Bober ◽  
G E Lyons ◽  
T Braun ◽  
G Cossu ◽  
M Buckingham ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Mouse Embryo ◽  
Regulatory Gene ◽  
Fiber Formation ◽  
Mouse Development ◽  
Limb Buds ◽  
Biphasic Pattern ◽  
Early Mouse ◽  
Temporal Expression Pattern ◽  
High Level

The spatial and temporal expression pattern of the muscle regulatory gene Myf-6 (MRF4/herculin) has been investigated by in situ hybridization during embryonic and fetal mouse development. Here, we report that the Myf-6 gene shows a biphasic pattern of expression. Myf-6 transcripts are first detected in the most rostral somites of the mouse embryo at 9 d of gestation and accumulate progressively in myotomal cells along the rostro-caudal axis. This expression is transient and Myf-6 mRNA can no longer be detected in myotomal cells after day 12 post coitum (p.c.). In contrast to other muscle determination genes (MyoD1, myogenin, Myf-5), Myf-6 mRNA is not detected in limb buds or visceral arches and skeletal muscle of the mouse embryo (day 8-15 p.c.). In fetal mice, Myf-6 transcripts appear at day 16 p.c. in all skeletal muscles, and the gene continues to be expressed at a high level after birth. These results suggest that early Myf-6 expression may be restricted to a population of myogenic cells that does not contribute to the embryonic muscle masses in limb buds and visceral arches. The reappearance of Myf-6 mRNA in fetal skeletal muscle coincides approximately with secondary muscle fiber formation and the onset of innervation.

scholarly journals Targeted Disruption of the Protein Kinase SGK3/CISK Impairs Postnatal Hair Follicle Development

2004 ◽  
Vol 15 (9) ◽  
pp. 4278-4288 ◽  
Author(s):  
James A. McCormick ◽  
Yuxi Feng ◽  
Kevin Dawson ◽  
Martin J. Behne ◽  
Benjamin Yu ◽  
...  
Keyword(s):  
Hair Follicle ◽  
Gene Transcription ◽  
Cultured Cells ◽  
Nuclear Accumulation ◽  
Follicle Development ◽  
Phosphatidylinositol 3 Kinase ◽  
Targeted Disruption ◽  
Hair Follicle Development ◽  
Close Relatives

Members of the serum- and glucocorticoid-regulated kinase (SGK) family are important mediators of growth factor and hormone signaling that, like their close relatives in the Akt family, are regulated by lipid products of phosphatidylinositol-3-kinase. SGK3 has been implicated in the control of cell survival and regulation of ion channel activity in cultured cells. To begin to dissect the in vivo functions of SGK3, we generated and characterized Sgk3 null mice. These mice are viable and fertile, and in contrast to mice lacking SGK1 or Akt2, respectively, display normal sodium handling and glucose tolerance. However, although normal at birth, by postpartum day 4 they have begun to display an unexpected defect in hair follicle morphogenesis. The abnormality in hair follicle development is preceded by a defect in proliferation and nuclear accumulation of β-catenin in hair bulb keratinocytes. Furthermore, in cultured keratinocytes, heterologous expression of SGK3 potently modulates activation of β-catenin/Lef-1–mediated gene transcription. These data establish a role for SGK3 in normal postnatal hair follicle development, possibly involving effects on β-catenin/Lef-1–mediated gene transcription.

Localization of Phospho-β-dystroglycan (pY892) to an Intracellular Vesicular Compartment in Cultured Cells and Skeletal Muscle Fibers in Vivo†

Biochemistry ◽  
2003 ◽  
Vol 42 (23) ◽  
pp. 7110-7123 ◽  
Author(s):  
Federica Sotgia ◽  
Gloria Bonuccelli ◽  
Mark Bedford ◽  
Andrea Brancaccio ◽  
Ulrike Mayer ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cultured Cells ◽  
Muscle Fibers ◽  
Skeletal Muscle Fibers ◽  
Vesicular Compartment

scholarly journals Molecular Signature of Mineralocorticoid Receptor Signaling in Cardiomyocytes: From Cultured Cells to Mouse Heart

Endocrinology ◽  
2010 ◽  
Vol 151 (9) ◽  
pp. 4467-4476 ◽  
Author(s):  
Celine Latouche ◽  
Yannis Sainte-Marie ◽  
Marja Steenman ◽  
Paulo Castro Chaves ◽  
Aniko Naray-Fejes-Toth ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Mineralocorticoid Receptor ◽  
Cultured Cells ◽  
Ex Vivo ◽  
Plasminogen Activator Inhibitor ◽  
Molecular Signature ◽  
H9c2 Cell ◽  
Mouse Heart ◽  
Plasminogen Activator Inhibitor 1

Excess mineralocorticoid signaling is deleterious for cardiovascular functions, as demonstrated by the beneficial effects of mineralocorticoid receptor (MR) antagonism on morbidity and mortality in patients with heart failure. However, the understanding of signaling pathways after MR activation in the heart remains limited. We performed transcriptomic analyses in the heart of double-transgenic mice with conditional, cardiomyocyte-specific, overexpression of the MR (MRcardio mice) or the glucocorticoid receptor (GR; GRcardio mice). Some of the genes induced in MRcardio mice were selected for comparative evaluation (real time PCR) in vivo in the heart of mice and ex vivo in the MR-expressing cardiomyocyte H9C2 cell line after aldosterone or corticosterone treatment. We demonstrate that chronic MR overexpression in the heart results in a limited number of induced (n = 24) and repressed (n = 22) genes compared with their control littermates. These genes are specifically modulated by MR because there is limited overlap (three induced, four repressed) with the genes that are regulated in the heart of GRcardio mice (compared with control mice: 70 induced, 73 repressed). Interestingly, some MR-induced genes that are up-regulated in vivo in mice are also induced by 24-h aldosterone treatment in H9C2 cells, such as plasminogen activator inhibitor 1 and Serpina-3 (α1-antichymotrypsin). The signaling pathways that are affected by long-term activation of MR may be of particular interest to design novel therapeutic targets in cardiac diseases.

scholarly journals Cardiac endothelial cells isolated from mouse heart - a novel model for radiobiology.

2011 ◽  
Vol 58 (3) ◽  
Author(s):  
Karol Jelonek ◽  
Anna Walaszczyk ◽  
Dorota Gabryś ◽  
Monika Pietrowska ◽  
Chryso Kanthou ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Ionizing Radiation ◽  
Cultured Cells ◽  
Clinical Problem ◽  
High Dose ◽  
Mouse Heart ◽  
Important Clinical Problem ◽  
Induced Apoptosis

Cardiovascular disease is recognized as an important clinical problem in radiotherapy and radiation protection. However, only few radiobiological models relevant for assessment of cardiotoxic effects of ionizing radiation are available. Here we describe the isolation of mouse primary cardiac endothelial cells, a possible target for cardiotoxic effects of radiation. Cells isolated from hearts of juvenile mice were cultured and irradiated in vitro. In addition, cells isolated from hearts of locally irradiated adult animals (up to 6 days after irradiation) were tested. A dose-dependent formation of histone γH2A.X foci was observed after in vitro irradiation of cultured cells. However, such cells were resistant to radiation-induced apoptosis. Increased levels of actin stress fibres were observed in the cytoplasm of cardiac endothelial cells irradiated in vitro or isolated from irradiated animals. A high dose of 16 Gy did not increase permeability to Dextran in monolayers formed by endothelial cells. Up-regulated expression of Vcam1, Sele and Hsp70i genes was detected after irradiation in vitro and in cells isolated few days after irradiation in vivo. The increased level of actin stress fibres and enhanced expression of stress-response genes in irradiated endothelial cells are potentially involved in cardiotoxic effects of ionizing radiation.

scholarly journals Dietary protein deprivation decreases the serine phosphorylation of insulin receptor substrate-1 in rat skeletal muscle

2004 ◽  
Vol 32 (2) ◽  
pp. 519-531 ◽  
Author(s):  
Y Toyoshima ◽  
Y Ohne ◽  
SI Takahashi ◽  
T Noguchi ◽  
H Kato
Keyword(s):  
Skeletal Muscle ◽  
Insulin Receptor ◽  
Tyrosine Phosphorylation ◽  
Dietary Protein ◽  
Cultured Cells ◽  
Insulin Injection ◽  
The State ◽  
Protein Malnutrition ◽  
Serine Phosphorylation

Evidence has shown that protein malnutrition tends to increase peripheral insulin sensitivity, but the molecular mechanism underlying this increase is not yet clear. Here we show that, in rat muscle, the state of insulin receptor (IR) substrate-1 (IRS-1), a pivotal component of the signaling pathway of the IR, changes drastically according to protein supply. After rats were fed a protein-free diet (PF) or a 12% casein diet for 1 week, their IR and IRS-1 states were analyzed by immunoblotting using various antibodies. PF slightly increased the amount of IR without affecting the state of IR tyrosine phosphorylation. In contrast, PF decreased the amount of IRS-1 and markedly increased phosphorylation of IRS-1 tyrosine residues after insulin injection. Moreover, IRS-1 in PF rats exhibited faster mobility in SDS-PAGE as well as far less phosphorylation of Ser612 and Ser307, indicating hypophosphorylation on its serine residues. Results of additional experiments using energy-restricted (pair-fed) rats and streptozotocin-induced diabetic rats suggest that dietary protein deficiency by itself alters serine phosphorylation of IRS-1, while the up-regulation of tyrosine phosphorylation requires other factors, such as a reduction in basal plasma insulin. The serine dephosphorylation followed by up-regulation of insulin-dependent IRS-1 tyrosine phosphorylation in skeletal muscle of PF rats in vivo is similar to a phenomenon observed in cultured cells under restriction of amino acids in the medium. With these findings, it could be inferred that the reduction of serine phosphorylation contributes to the sensitization of IRS-1 to IR tyrosine kinase under protein malnutrition.

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