scholarly journals Tissue-wide coordination of calcium signaling regulates the epithelial stem cell pool during homeostasis

2021 ◽  
Author(s):  
Jessica L Moore ◽  
Feng Gao ◽  
Catherine Matte-Martone ◽  
Shuangshuang Du ◽  
Elizabeth Lathrop ◽  
...  
Keyword(s):  
Stem Cell ◽  
Connexin 43 ◽  
Basal Layer ◽  
Cell Communication ◽  
Tissue Level ◽  
Signaling Dynamics ◽  
Scattering Transform ◽  
Junction Protein ◽  
A Cell

Regenerative processes in the mammalian skin require coordinated cell-cell communication. Ca2+ signaling can coordinate tissue-level responses in developing and wounded epithelia in tissue explants and invertebrates. However, its role in the homeostatic, regenerative basal layer of the skin epithelium is unknown due to significant challenges in studying signaling dynamics in a spatially complex tissue context in live mice. Here we combine in vivo imaging of dynamic Ca2+ signaling at the single cell level across thousands of cells with a novel computational approach, Geometric Scattering Trajectory Homology (GSTH). GSTH models Ca2+ as signals over a cell adjacency graph and uses a multi-level wavelet-like transform (called a scattering transform) to extract signaling patterns from our high dimensional in vivo datasets. We discover local Ca2+ signaling patterns are orchestrated so that signals flow in a coordinated and directed manner across the tissue, distinct from topographically uncoordinated Ca2+ signaling in excitatory tissues. Directed Ca2+ signaling is regulated by the major gap junction protein in the epidermal stem cell layer, Connexin 43 (Cx43). Cx43 gap junctions are dissociated as cells progress through the cell cycle out of G1 and play an essential role in the progression of stem cells from G2 towards mitosis. Finally, G2 cells display related signaling patterns and are essential for tissue-level signaling coordination. Together, our results provide insight into how such a ubiquitous signaling pathway regulates highly specific behaviors and outcomes at a tissue-wide level to maintain proper homeostasis.

scholarly journals Microfluidic and Lab-on-a-Chip Systems for Cutaneous Wound Healing Studies

2021 ◽  
Author(s):  
Ghazal Shabestani Monfared ◽  
Peter Ertl ◽  
Mario Rothbauer
Keyword(s):  
Wound Healing ◽  
Molecular Mechanisms ◽  
Chronic Wounds ◽  
Cell Communication ◽  
Lab On A Chip ◽  
Tissue Level ◽  
Cutaneous Wound Healing ◽  
Cutaneous Wound

Cutaneous wound healing is a complex multi-stage process involving direct and indirect cell communication events with the aim of efficiently restoring the barrier function of the skin. One key aspect in cutaneous wound healing is associated with cell movement and migration into the physically, chemically and biologically injured area resulting in wound closure. Understanding the conditions under which cell migration is impaired and elucidating the cellular and molecular mechanisms that improve healing dynamics is therefore crucial in devising novel therapeutic strategies to elevate patient suffering, reduce scaring and eliminate chronic wounds. Following the global trend towards automation, miniaturization and integration of cell-based assays into microphysiological systems, conventional wound healing assays such as the scratch assay or cell exclusion assay have recently been translated and improved using microfluidics and lab-on-a-chip technologies. These miniaturized cell analysis systems allow precise spatial and temporal control over a range of dynamic microenvironmental factors including shear stress, biochemical and oxygen gradients to create more reliable in vitro models that resemble the in vivo microenvironment of a wound more closely on a molecular, cellular, and tissue level. The current review provides (a) an overview on the main molecular and cellular processes that take place during wound healing, (b) a brief introduction into conventional in vitro wound healing assays, and (c) a perspective on future cutaneous and vascular wound healing research using microfluidic technology.

Analysis of distribution patterns of gap junctions during development of embryonic chick facial primordia and brain

Development ◽  
1991 ◽  
Vol 111 (2) ◽  
pp. 509-522
Author(s):  
R. Minkoff ◽  
S.B. Parker ◽  
E.L. Hertzberg
Keyword(s):  
Gap Junctions ◽  
Gap Junction ◽  
Uniform Distribution ◽  
Rat Liver ◽  
Connexin 43 ◽  
Cell Communication ◽  
Exterior Surface ◽  
Junction Protein ◽  
Primary Palate ◽  
Gap Junction Protein

Gap junction distribution in the facial primordia of chick embryos at the time of primary palate formation was studied employing indirect immunofluorescence localization with antibodies to gap junction proteins initially identified in rat liver (27 × 10(3) Mr, connexin 32) and heart (43 × 10(3) Mr, connexin 43). Immunolocalization with antibodies to the rat liver gap junction protein (27 × 10(3) Mr) demonstrated a ubiquitous and uniform distribution in all regions of the epithelium and mesenchyme except the nasal placode. In the placodal epithelium, a unique non-random distribution was found characterized by two zones: a very heavy concentration of signal in the superficial layer of cells adjacent to the exterior surface and a region devoid of detectable signal in the interior cell layer adjacent to the mesenchyme. This pattern was seen during all stages of placode invagination that were examined. The separation of gap junctions in distinct cell layers was unique to the nasal placode, and was not found in any other region of the developing primary palate. One other tissue was found that exhibited this pattern-the developing neural epithelium of the brain and retina. These observations suggest the presence of region-specific signaling mechanisms and, possibly, an impedance of cell communication among subpopulations of cells in these structures at critical stages of development. Immunolocalization with antibodies to the ‘heart’ 43 × 10(3) Mr gap junction protein also revealed the presence of gap junction protein in facial primordia and neural epithelium. A non-uniform distribution of immunoreactivity was also observed for connexin 43.

Accept or Reject: The Role of Immune Tolerance in the Development of Stem Cell Therapies and Possible Future Approaches

2020 ◽  
pp. 019262332091824
Author(s):  
Richard Haworth ◽  
Michaela Sharpe
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Embryonic Stem ◽  
Immune Recognition ◽  
Cell Of Origin ◽  
In Vivo Models ◽  
Cell Product ◽  
A Cell

In 2011, Goldring and colleagues published a review article describing the potential safety issues of novel stem cell-derived treatments. Immunogenicity and immunotoxicity of the administered cell product were considered risks in the light of clinical experience of transplantation. The relative immunogenicity of mesenchymal stem cells, embryonic stem cells (ESCs), and induced pluripotent stem cells (iPSCs) was being addressed through in vitro and in vivo models. But the question arose as to whether the implanted cells needed to be identical to the recipient in every respect, including epigenetically, to evade immune recognition? If so, this set a high bar which may preclude use of many cells derived from iPSCs which have vestiges of a fetal phenotype and epigenetic memory of their cell of origin. However, for autologous iPSCs, the immunogenicity reduces once the surface antigen expression profile becomes close to that of the parent somatic cells. Therefore, a cell product containing incompletely differentiated cells could be more immunogenic. The properties of the administered cells, the immune privilege of the administration site, and the host immune status influence graft success or failure. In addition, the various approaches available to characterize potential immunogenicity of a cell therapy will be discussed.

scholarly journals Connexin43 Deficiency Causes Delayed Ossification, Craniofacial Abnormalities, and Osteoblast Dysfunction

2000 ◽  
Vol 151 (4) ◽  
pp. 931-944 ◽  
Author(s):  
Fernando Lecanda ◽  
Pamela M. Warlow ◽  
Sharmin Sheikh ◽  
Federico Furlan ◽  
Thomas H. Steinberg ◽  
...  
Keyword(s):  
Neural Crest ◽  
Cell Communication ◽  
Neural Crest Cell ◽  
Osteoblastic Differentiation ◽  
Null Mouse ◽  
Appendicular Skeleton ◽  
Differentiation Markers ◽  
Essentially Normal ◽  
Junction Protein

Connexin(Cx)43 is the major gap junction protein present in osteoblasts. We have shown that overexpression of Cx45 in osteoblasts expressing endogenous Cx43 leads to decreased cell–cell communication (Koval, M., S.T. Geist, E.M. Westphale, A.E. Kemendy, R. Civitelli, E.C. Beyer, and T.H. Steinberg. 1995. J. Cell Biol. 130:987–995) and transcriptional downregulation of several osteoblastic differentiation markers (Lecanda, F., D.A. Towler, K. Ziambaras, S.-L. Cheng, M. Koval, T.H. Steinberg, and R. Civitelli. 1998. Mol. Biol. Cell 9:2249–2258). Here, using the Cx43-null mouse model, we determined whether genetic deficiency of Cx43 affects skeletal development in vivo. Both intramembranous and endochondral ossification of the cranial vault were delayed in the mutant embryos, and cranial bones originating from migratory neural crest cells were also hypoplastic, leaving an open foramen at birth. Cx43-deficient animals also exhibited retarded ossification of the clavicles, ribs, vertebrae, and limbs, demonstrating that skeletal abnormalities are not restricted to a neural crest defect. However, the axial and appendicular skeleton of Cx43-null animals were essentially normal at birth. Cell to cell diffusion of calcein was poor among Cx43-deficient osteoblasts, whose differentiated phenotypic profile and mineralization potential were greatly impaired, compared with wild-type cells. Therefore, in addition to the reported neural crest cell defect, lack of Cx43 also causes a generalized osteoblast dysfunction, leading to delayed mineralization and skull abnormalities. Cell to cell signaling, mediated by Cx43 gap junctions, was critical for normal osteogenesis, craniofacial development, and osteoblastic function.

scholarly journals Gap junction internalization and processing in vivo: a 3D immuno-electron microscopy study

2020 ◽  
pp. jcs.252726
Author(s):  
Rachael P. Norris ◽  
Mark Terasaki
Keyword(s):  
Gap Junctions ◽  
Gap Junction ◽  
Connexin 43 ◽  
New Technology ◽  
Cell Communication ◽  
Membrane Vesicles ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Annular Gap

Gap junctions have well-established roles in cell-cell communication by way of forming permeable intercellular channels. Less is understood about their internalization, which forms double membrane vesicles containing cytosol and membranes from another cell, called connexosomes or annular gap junctions. Here, we systematically investigated the fate of connexosomes in intact ovarian follicles. High pressure frozen, serial sectioned tissue was immunogold labeled for Connexin 43. Within a volume corresponding to ∼35 cells, every labeled structure was categorized and its surface area was measured. Measurements support the concept that multiple connexosomes form from larger invaginated gap junctions. Subsequently, the inner and outer membranes separate, Cx43 immunogenicity is lost from the outer membrane, and the inner membrane appears to undergo fission. One pathway for processing involves lysosomes, based on localization of Cathespin B to some processed connexosomes. In summary, this study demonstrates new technology for high-resolution analyses of gap junction processing.

Pseudomonas aeruginosa tolerance to tobramycin, hydrogen peroxide and polymorphonuclear leukocytes is quorum-sensing dependent

Microbiology ◽  
2005 ◽  
Vol 151 (2) ◽  
pp. 373-383 ◽  
Author(s):  
Thomas Bjarnsholt ◽  
Peter Østrup Jensen ◽  
Mette Burmølle ◽  
Morten Hentzer ◽  
Janus A. J. Haagensen ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Polymorphonuclear Leukocytes ◽  
Present Report ◽  
Cell Communication ◽  
A Cell ◽  
Opportunistic Human Pathogen ◽  
Conventional Antibiotics

The opportunistic human pathogen Pseudomonas aeruginosa is the predominant micro-organism of chronic lung infections in cystic fibrosis (CF) patients. P. aeruginosa colonizes the CF lungs by forming biofilm structures in the alveoli. In the biofilm mode of growth the bacteria are highly tolerant to otherwise lethal doses of antibiotics and are protected from bactericidal activity of polymorphonuclear leukocytes (PMNs). P. aeruginosa controls the expression of many of its virulence factors by means of a cell–cell communication system termed quorum sensing (QS). In the present report it is demonstrated that biofilm bacteria in which QS is blocked either by mutation or by administration of QS inhibitory drugs are sensitive to treatment with tobramycin and H2O2, and are readily phagocytosed by PMNs, in contrast to bacteria with functional QS systems. In contrast to the wild-type, QS-deficient biofilms led to an immediate respiratory-burst activation of the PMNs in vitro. In vivo QS-deficient mutants provoked a higher degree of inflammation. It is suggested that quorum signals and QS-inhibitory drugs play direct and opposite roles in this process. Consequently, the faster and highly efficient clearance of QS-deficient bacteria in vivo is probably a two-sided phenomenon: down regulation of virulence and activation of the innate immune system. These data also suggest that a combination of the action of PMNs and QS inhibitors along with conventional antibiotics would eliminate the biofilm-forming bacteria before a chronic infection is established.

scholarly journals Connexin 43 confers chemoresistance through activating PI3K

Oncogenesis ◽  
2022 ◽  
Vol 11 (1) ◽  
Author(s):  
Kevin J. Pridham ◽  
Farah Shah ◽  
Kasen R. Hutchings ◽  
Kevin L. Sheng ◽  
Sujuan Guo ◽  
...  
Keyword(s):  
Poor Prognosis ◽  
Connexin 43 ◽  
Therapeutic Potential ◽  
Mrna Levels ◽  
Phosphatidylinositol 3 Kinase ◽  
Junction Protein ◽  
Gap Junction Protein ◽  
Cx43 Mrna

AbstractCircumventing chemoresistance is crucial for effectively treating cancer including glioblastoma, a lethal brain cancer. The gap junction protein connexin 43 (Cx43) renders glioblastoma resistant to chemotherapy; however, targeting Cx43 is difficult because mechanisms underlying Cx43-mediated chemoresistance remain elusive. Here we report that Cx43, but not other connexins, is highly expressed in a subpopulation of glioblastoma and Cx43 mRNA levels strongly correlate with poor prognosis and chemoresistance in this population, making Cx43 the prime therapeutic target among all connexins. Depleting Cx43 or treating cells with αCT1–a Cx43 peptide inhibitor that sensitizes glioblastoma to the chemotherapy temozolomide–inactivates phosphatidylinositol-3 kinase (PI3K), whereas overexpression of Cx43 activates this signaling. Moreover, αCT1-induced chemo-sensitization is counteracted by a PI3K active mutant. Further research reveals that αCT1 inactivates PI3K without blocking the release of PI3K-activating molecules from membrane channels and that Cx43 selectively binds to the PI3K catalytic subunit β (PIK3CB, also called PI3Kβ or p110β), suggesting that Cx43 activates PIK3CB/p110β independent of its channel functions. To explore the therapeutic potential of simultaneously targeting Cx43 and PIK3CB/p110β, αCT1 is combined with TGX-221 or GSK2636771, two PIK3CB/p110β-selective inhibitors. These two different treatments synergistically inactivate PI3K and sensitize glioblastoma cells to temozolomide in vitro and in vivo. Our study has revealed novel mechanistic insights into Cx43/PI3K-mediated temozolomide resistance in glioblastoma and demonstrated that targeting Cx43 and PIK3CB/p110β together is an effective therapeutic approach for overcoming chemoresistance.

scholarly journals Mechanism of antrocytic connexin-43 autophagy degradation in oxygen-glucose deprivation and its effect on neuroinflammation

2019 ◽  
Author(s):  
Xinyu Wang ◽  
Liangshu Feng ◽  
Meiying Xin ◽  
Yulei Hao ◽  
Xu Wang ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Connexin 43 ◽  
Cell Communication ◽  
Glucose Deprivation ◽  
In Vivo Model ◽  
Oxygen Glucose Deprivation ◽  
Cx43 Protein ◽  
Protein Levels

Abstract Background : Connexin 43 (Cx43) are the most widely distributed gap junction proteins in the nervous system. Cx43 enables cell-to-cell communication and plays an important role in ion transport, substrate exchange and delivery of information , which have been implicated in cerebral ischemia injury. Our previous work revealed the relationships between Cx43 and glia-mediated neuroinflammation through the release of ATP in oxygen-glucose deprivation (OGD), which means degradation of Cx43 may improve neuroinflammatory damage during OGD injury . However, the roles of Cx43 degradation and neuroinflammation caused by OGD remain unclear. Methods: We used primary cultured astrocytes treated with OGD as an in vitro model of cerebral ischemia injury and we used middle cerebral artery occlusion (MCAO) model as an in vivo model of cerebral ischemia. HeLa cells were used in overexpression experiments. Cx43 protein levels were determined by western blotting. The interaction between Cx43 and related autophagy receptors was determined by co-immunoprecipitation and immunofluorescence. The gene knockdown (KD) of ATG5, OPTN, NDP52, PINK1 and Cx43 was applied by siRNA transfection. Related cytokines were detected by cytometric bead assay. Results: We found that Cx43 protein levels increased after ischemia in gene KD of ATG5, OPTN, NDP52 and PINK1 primary astrocytes. The interaction of Cx43 with OPTN, NDP52 and PINK1 was increased after cerebral ischemia injury in vitro and vivo. While the interaction was weakened after point mutation of Cx43 at Ser368, Tyr265 and Tyr247. Meanwhile, IL-10 upregulated during OGD after KD of ATG5, OPTN, NDP52 and PINK1 in astrocytes , while TNF downregulated during OGD after KD of ATG5, OPTN, NDP52 and PINK1 in astrocytes. Conclusions: Our results suggest that degradation of Cx43 is caused by selective autophagy during ischemia injury and the autophagy degradation of Cx43 plays important roles in neuroinflammation mediated by OGD injury. Treatment targeting Cx43 degradation pathway can improve neuroinflammation responses induced by OGD injury , which provide novel therapeutic strategies and crosstalk between autophagy and neuroinflammation.

Abstract 206: Stem Cell-derived Exosomes Induce Cardiac Repair via mRNA Modification

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Prabhu Mathiyalagan ◽  
Yaxuan Liang ◽  
Adriano S Martins ◽  
Douglas W Losordo ◽  
Roger J Hajjar ◽  
...  
Keyword(s):  
Stem Cell ◽  
Myocardial Ischemia ◽  
Target Genes ◽  
Critical Role ◽  
Cell Communication ◽  
Target Cells ◽  
Mouse Heart ◽  
Loss Of Function

Exosomes are cell-derived nanovesicles that carry and shuttle microRNAs (miRNAs) to mediate cell-cell communication. Vast majority of cell types including cardiac myocytes and progenitors actively secrete exosomes, whose miRNA contents are altered after physiological or pathological changes such as myocardial ischemia (MI). In this new study, we have discovered that chemical modification to mRNAs is a novel regulator of ischemia-induced gene expression changes in the heart. We hypothesized that the benefits of human CD34 + stem cell-derived exosomes (CD34exo) are mediated by mRNA modifications in the target cells via miRNA delivery. MiRNA profiling and bioinformatic analysis identified that CD34exo is selectively enriched with a number of miRNAs that directly target genes implicated in regulation of mRNA modifications. Interestingly, under myocardial ischemia, there was a significant increase in mRNA modifications in the mouse heart, which was decreased by about 70% with CD34exo-treatment. In line with the in vivo MI data, in vitro hypoxic stimulation in neonatal / adult rodent myocytes and non-myocytes increased mRNA modifications and controls known regulators of those mRNA modifications. Loss-of-function studies for regulators of mRNA modifications attenuated hypoxia-induced changes to epitranscriptome indicating important roles for these molecules under stress conditions. Finally, using gain-of-function and loss-of-function studies, we demonstrate that miR-126, one of the most enriched miRNAs in CD34exo, plays a critical role in regulating the mRNA modifications. We conclude that miRNAs enriched in CD34exo mediate their cardioprotective effect at least in part, by regulating the mRNA epitranscriptome of the target cell. Our new data suggests hypoxia as a novel regulator of the mRNA epitranscriptome and provides novel insights to post-transcriptional gene regulation in the heart.

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