scholarly journals Tip cell-specific requirement for an atypical Gpr124- and Reck-dependent Wnt/β-catenin pathway during brain angiogenesis

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Benoit Vanhollebeke ◽  
Oliver A Stone ◽  
Naguissa Bostaille ◽  
Chris Cho ◽  
Yulian Zhou ◽  
...  
Keyword(s):  
Cell Function ◽  
Critical Role ◽  
Tip Cell ◽  
Signaling Complex ◽  
Mmp Inhibitor ◽  
Wnt Ligands ◽  
Multistep Process ◽  
Organ Specific ◽  
Sense And Respond ◽  
Brain Angiogenesis

Despite the critical role of endothelial Wnt/β-catenin signaling during central nervous system (CNS) vascularization, how endothelial cells sense and respond to specific Wnt ligands and what aspects of the multistep process of intra-cerebral blood vessel morphogenesis are controlled by these angiogenic signals remain poorly understood. We addressed these questions at single-cell resolution in zebrafish embryos. We identify the GPI-anchored MMP inhibitor Reck and the adhesion GPCR Gpr124 as integral components of a Wnt7a/Wnt7b-specific signaling complex required for brain angiogenesis and dorsal root ganglia neurogenesis. We further show that this atypical Wnt/β-catenin signaling pathway selectively controls endothelial tip cell function and hence, that mosaic restoration of single wild-type tip cells in Wnt/β-catenin-deficient perineural vessels is sufficient to initiate the formation of CNS vessels. Our results identify molecular determinants of ligand specificity of Wnt/β-catenin signaling and provide evidence for organ-specific control of vascular invasion through tight modulation of tip cell function.

scholarly journals Hypoxia. 4. Hypoxia and ion channel function

2011 ◽  
Vol 300 (5) ◽  
pp. C951-C967 ◽  
Author(s):  
Larissa A. Shimoda ◽  
Jan Polak
Keyword(s):  
Ion Channels ◽  
Cell Function ◽  
Critical Role ◽  
Cardiac Contractility ◽  
Cell Types ◽  
Cellular Processes ◽  
Oxygen Sensitive ◽  
Sense And Respond ◽  
And Function ◽  
And Control

The ability to sense and respond to oxygen deprivation is required for survival; thus, understanding the mechanisms by which changes in oxygen are linked to cell viability and function is of great importance. Ion channels play a critical role in regulating cell function in a wide variety of biological processes, including neuronal transmission, control of ventilation, cardiac contractility, and control of vasomotor tone. Since the 1988 discovery of oxygen-sensitive potassium channels in chemoreceptors, the effect of hypoxia on an assortment of ion channels has been studied in an array of cell types. In this review, we describe the effects of both acute and sustained hypoxia (continuous and intermittent) on mammalian ion channels in several tissues, the mode of action, and their contribution to diverse cellular processes.

scholarly journals NRP1 acts cell autonomously in endothelium to promote tip cell function during sprouting angiogenesis

Blood ◽  
2013 ◽  
Vol 121 (12) ◽  
pp. 2352-2362 ◽  
Author(s):  
Alessandro Fantin ◽  
Joaquim M. Vieira ◽  
Alice Plein ◽  
Laura Denti ◽  
Marcus Fruttiger ◽  
...  
Keyword(s):  
Cell Function ◽  
Tip Cell ◽  
Sprouting Angiogenesis ◽  
Key Points ◽  
Heterotypic Interactions ◽  
The Brain ◽  
Brain Angiogenesis

Key Points NRP1 promotes brain angiogenesis cell autonomously in endothelium, independently of heterotypic interactions with nonendothelial cells. NRP1 plays a key role in endothelial tip rather than stalk cells during vessel sprouting in the brain.

scholarly journals Empowering Muscle Stem Cells for the Treatment of Duchenne Muscular Dystrophy

2021 ◽  
pp. 1-14
Author(s):  
Romina L. Filippelli ◽  
Natasha C. Chang
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Cell Function ◽  
Critical Role ◽  
Membrane Integrity ◽  
Muscle Membrane ◽  
Muscle Stem Cell ◽  
Muscle Stem Cells

Duchenne muscular dystrophy (DMD) is a devastating and debilitating muscle degenerative disease affecting 1 in every 3,500 male births worldwide. DMD is progressive and fatal; accumulated weakening of the muscle tissue leads to an inability to walk and eventual loss of life due to respiratory and cardiac failure. Importantly, there remains no effective cure for DMD. DMD is caused by defective expression of the <i>DMD</i> gene, which encodes for dystrophin, a component of the dystrophin glycoprotein complex. In muscle fibers, this protein complex plays a critical role in maintaining muscle membrane integrity. Emerging studies have shown that muscle stem cells, which are adult stem cells responsible for muscle repair, are also affected in DMD. DMD muscle stem cells do not function as healthy muscle stem cells, and their impairment contributes to disease progression. Deficiencies in muscle stem cell function include impaired establishment of cell polarity leading to defective asymmetric stem cell division, reduced myogenic commitment, impaired differentiation, altered metabolism, and enhanced entry into senescence. Altogether, these findings indicate that DMD muscle stem cells are dysfunctional and have impaired regenerative potential. Although recent advances in adeno-associated vector and antisense oligonucleotide-mediated mechanisms for gene therapy have shown clinical promise, the current therapeutic strategies for muscular dystrophy do not effectively target muscle stem cells and do not address the deficiencies in muscle stem cell function. Here, we discuss the merits of restoring endogenous muscle stem cell function in degenerating muscle as a viable regenerative medicine strategy to mitigate DMD.

scholarly journals CD4+ regulatory T cells require CTLA-4 for the maintenance of systemic tolerance

2009 ◽  
Vol 206 (2) ◽  
pp. 421-434 ◽  
Author(s):  
Randall H. Friedline ◽  
David S. Brown ◽  
Hai Nguyen ◽  
Hardy Kornfeld ◽  
JinHee Lee ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Cell Function ◽  
Cytotoxic T Lymphocyte ◽  
Critical Role ◽  
Lymphoproliferative Disease ◽  
In Trans ◽  
And Function

Cytotoxic T lymphocyte antigen-4 (CTLA-4) plays a critical role in negatively regulating T cell responses and has also been implicated in the development and function of natural FOXP3+ regulatory T cells. CTLA-4–deficient mice develop fatal, early onset lymphoproliferative disease. However, chimeric mice containing both CTLA-4–deficient and –sufficient bone marrow (BM)–derived cells do not develop disease, indicating that CTLA-4 can act in trans to maintain T cell self-tolerance. Using genetically mixed blastocyst and BM chimaeras as well as in vivo T cell transfer systems, we demonstrate that in vivo regulation of Ctla4−/− T cells in trans by CTLA-4–sufficient T cells is a reversible process that requires the persistent presence of FOXP3+ regulatory T cells with a diverse TCR repertoire. Based on gene expression studies, the regulatory T cells do not appear to act directly on T cells, suggesting they may instead modulate the stimulatory activities of antigen-presenting cells. These results demonstrate that CTLA-4 is absolutely required for FOXP3+ regulatory T cell function in vivo.

scholarly journals Host genetics play a critical role in controlling CD8 T cell function and lethal immunopathology during chronic viral infection

2017 ◽  
Vol 13 (7) ◽  
pp. e1006498 ◽  
Author(s):  
Allison F. Christiaansen ◽  
Megan E. Schmidt ◽  
Stacey M. Hartwig ◽  
Steven M. Varga
Keyword(s):  
T Cell ◽  
Viral Infection ◽  
Cell Function ◽  
Critical Role ◽  
Cd8 T Cell ◽  
Chronic Viral Infection ◽  
Host Genetics ◽  
T Cell Function

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 Mast cell function in prostate inflammation, fibrosis, and smooth muscle cell dysfunction

2021 ◽  
Author(s):  
Goutham Pattabiraman ◽  
Ashlee J Bell-Cohn ◽  
Stephen F. Murphy ◽  
Daniel J Mazur ◽  
Anthony J Schaeffer ◽  
...  
Keyword(s):  
Mast Cell ◽  
Smooth Muscle ◽  
Mast Cells ◽  
Cell Activation ◽  
Cell Function ◽  
Critical Role ◽  
Smooth Muscle Contraction ◽  
Urinary Dysfunction ◽  
Mast Cell Activation ◽  
Prostate Inflammation

Intraurethral inoculation of mice with uropathogenic E. coli (CP1) results in prostate inflammation, fibrosis, and urinary dysfunction, recapitulating some but not all of the pathognomonic clinical features associated with benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS). In both patients with LUTS and in CP1-infected mice, we observed increased numbers and activation of mast cells and elevated levels of prostate fibrosis. Therapeutic inhibition of mast cells using a combination of mast cell stabilizer (MCS), cromolyn sodium, and the histamine 1 receptor antagonist (H1RA), cetirizine di-hydrochloride, in the mouse model resulted in reduced mast cell activation in the prostate and significant alleviation of urinary dysfunction. Treated mice showed reduced prostate fibrosis, less infiltration of immune cells, and decreased inflammation. In addition, as opposed to symptomatic CP1-infected mice, treated mice showed reduced myosin light chain (MLC)-2 phosphorylation, a marker of prostate smooth muscle contraction. These results show that mast cells play a critical role in the pathophysiology of urinary dysfunction and may be an important therapeutic target for men with BPH/LUTS.

scholarly journals Dynamics of TCR repertoire and T cell function in COVID-19 convalescent individuals

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Lingjie Luo ◽  
Wenhua Liang ◽  
Jianfeng Pang ◽  
Gang Xu ◽  
Yingying Chen ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Function ◽  
Critical Role ◽  
World Health ◽  
Cell Repertoire ◽  
Metabolic Functions ◽  
Tcr Repertoire ◽  
Discharged Patients ◽  
Health Organization

AbstractSARS-CoV-2 outbreak has been declared by World Health Organization as a worldwide pandemic. However, there are many unknowns about the antigen-specific T-cell-mediated immune responses to SARS-CoV-2 infection. Here, we present both single-cell TCR-seq and RNA-seq to analyze the dynamics of TCR repertoire and immune metabolic functions of blood T cells collected from recently discharged COVID-19 patients. We found that while the diversity of TCR repertoire was increased in discharged patients, it returned to basal level ~1 week after becoming virus-free. The dynamics of T cell repertoire correlated with a profound shift of gene signatures from antiviral response to metabolism adaptation. We also demonstrated that the top expanded T cell clones (~10% of total T cells) display the key anti-viral features in CD8+ T cells, confirming a critical role of antigen-specific T cells in fighting against SARS-CoV-2. Our work provides a basis for further analysis of adaptive immunity in COVID-19 patients, and also has implications in developing a T-cell-based vaccine for SARS-CoV-2.

scholarly journals T cell receptor for antigen induces linker for activation of T cell–dependent activation of a negative signaling complex involving Dok-2, SHIP-1, and Grb-2

2006 ◽  
Vol 203 (11) ◽  
pp. 2509-2518 ◽  
Author(s):  
Shen Dong ◽  
Béatrice Corre ◽  
Eliane Foulon ◽  
Evelyne Dufour ◽  
André Veillette ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Critical Role ◽  
Adaptor Proteins ◽  
Cell Receptor ◽  
Negative Control ◽  
Inositol Polyphosphate ◽  
Tcr Signaling ◽  
Signaling Complex ◽  
Src Homology 2 Domain

Adaptor proteins positively or negatively regulate the T cell receptor for antigen (TCR) signaling cascade. We report that after TCR stimulation, the inhibitory adaptor downstream of kinase (Dok)-2 and its homologue Dok-1 are involved in a multimolecular complex including the lipid phosphatase Src homology 2 domain–containing inositol polyphosphate 5′-phosphatase (SHIP)-1 and Grb-2 which interacts with the membrane signaling scaffold linker for activation of T cells (LAT). Knockdown of LAT and SHIP-1 expression indicated that SHIP-1 favored recruitment of Dok-2 to LAT. Knockdown of Dok-2 and Dok-1 revealed their negative control on Akt and, unexpectedly, on Zap-70 activation. Our findings support the view that Dok-1 and -2 are critical elements of a LAT-dependent negative feedback loop that attenuates early TCR signal. Dok-1 and -2 may therefore exert a critical role in shaping the immune response and as gatekeepers for T cell tolerance.

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