The cellular environment controls the expression of engrailed-like protein in the cranial neuroepithelium of quail-chick chimeric embryos

Development ◽  
1991 ◽  
Vol 113 (3) ◽  
pp. 1037-1048 ◽  
Author(s):  
C.A. Gardner ◽  
K.F. Barald
Keyword(s):  
Chick Embryo ◽  
Protein Expression ◽  
Morphological Changes ◽  
Polyclonal Antiserum ◽  
Negative Region ◽  
Cellular Environment ◽  
Normal Environment ◽  
Restricted Region ◽  
Embryo Brain

We have previously shown that one of two chicken engrailed-like genes, chick En-2, is expressed in a restricted region of the early chick embryo brain: the mes/metencephalon (Gardner et al. 1988). In this study, we examine the role of the cellular environment in regulation of engrailed-like (En) protein expression in quail-chick chimeric embryos. Two types of transplant surgery were performed at the 9–15 somite stage to produce chimeric embryos. In the first, the mid-mesencephalic vesicle or caudal mesencephalic vesicle alar plate (which is En protein-positive) was transplanted from a quail embryo into an En protein-negative region of chick neuroepithelium, the prosencephalon (mMP and cMP grafts, respectively). In the second reciprocal surgery, prosencephalic alar plate which is En protein-negative, was transplanted into the En protein-positive mesencephalic vesicle (PM grafts). A polyclonal antiserum, alpha Enhb-1, which recognizes chick En proteins (Davis et al. 1991) was used to identify En-positive cells 48 h after surgery. In mMP embryos, 71% of integrated grafts had lost En expression (n = 17). In contrast, in cMP grafts, 93% of integrated grafts continued to stain with the antiserum (n = 14). In addition, in 86% of these embryos, the graft induced adjacent chick host diencephalic cells to become En protein-positive as well. All PM grafts contained aEnhb-1-positive cells; such cells never expressed this protein in their normal environment. These early changes in En protein expression correlate well with the morphological changes observed in similar graft surgeries assayed later in development. Thus, our results are consistent with the hypothesis that En genes play a role in the regionalization of the early cranial neuroepithelium.

Loss of active MEK1-ERK1/2 restores epithelial phenotype and morphogenesis in transdifferentiated MDCK cells

2003 ◽  
Vol 285 (3) ◽  
pp. C652-C661 ◽  
Author(s):  
Herbert Schramek ◽  
Elisabeth Feifel ◽  
Ingrid Marschitz ◽  
Nadejda Golochtchapova ◽  
Gerhard Gstraunthaler ◽  
...  
Keyword(s):  
Protein Expression ◽  
Epithelial Mesenchymal Transition ◽  
Morphological Changes ◽  
Three Dimensional ◽  
Relative Role ◽  
Collagen Gels ◽  
Mesenchymal Transition ◽  
Epithelial Phenotype ◽  
Erk1 Protein

Constitutive activation of the MAPK/ERK kinase (MEK)1-ERK2 signaling module in Madin-Darby canine kidney (MDCK)-C7 cells disrupts their ability to form cystlike structures in collagen gels and induces an invasive, myofibroblastlike phenotype. However, the reversibility of these cellular events, as well as the relative role of both MEK isoforms (MEK1 and MEK2) and both ERK isoforms (ERK1 and ERK2) during these processes, has not yet been investigated. We now report that loss of constitutively active MEK1 (caMEK1) and, thus, loss of active ERK1/2 in C7caMEK1 cells is associated with increased MEK2 protein expression, reexpression of ERK1 protein, and epithelial redifferentiation of these cells. The morphological changes toward an epithelial phenotype in these revertant cell lines (C7rev4, C7rev5, C7rev7) are reflected by the upregulation of epithelial marker proteins, such as E-cadherin, β-catenin, and cytokeratin, by the loss of α-smooth muscle actin expression, and by the ability of these epithelial revertants to form well-organized spherical cysts when grown in three-dimensional collagen gels. Further evidence for a role of the MEK1-ERK1/2 module in epithelial-mesenchymal transition was obtained from the analysis of two novel, spontaneously transdifferentiated MDCK-C7 cell clones (C7e1 and C7e2 cells). In these clones, increased MEK1/2-ERK1/2 phosphorylation, reduced MEK2 protein expression, and loss of ERK1 protein expression is associated with phenotypic alterations similar to those observed in transdifferentiated C7caMEK1 cells. C7e1 cells at least partially regained some of their epithelial characteristics at higher passages. In contrast, C7e2 cells maintained a transdifferentiated phenotype at high passage, were unable to generate cystlike epithelial structures, and retained invasive properties when grown on a three-dimensional collagen matrix. We conclude that in renal epithelial MDCK-C7 cells, stable epithelial-to-mesenchymal transition (EMT) is associated with loss of ERK1 protein expression, reduced MEK2 protein expression, and increased basal ERK2 phosphorylation. In contrast, loss of active MEK1-ERK1/2 results in increased MEK2 protein expression and reexpression of ERK1 protein, concomitant with the restoration of epithelial phenotype and the ability to form cystic structures.

Scanning electron microscopic study of collagen fibrillogenesis and extracellular compartmentalization in the chick embryo tendon

1986 ◽  
Vol 44 ◽  
pp. 208-209
Author(s):  
Grace C.H. Yang
Keyword(s):  
Chick Embryo ◽  
Extracellular Space ◽  
Fibroblast Cell ◽  
Collagen Fibrils ◽  
Electron Microscopic ◽  
Voltage Electron ◽  
Scanning Electron Microscopic Study ◽  
Microscopic Studies ◽  
And Function

The size and organization of collagen fibrils in the extracellular matrix is an important determinant of tissue structure and function. The synthesis and deposition of collagen involves multiple steps which begin within the cell and continue in the extracellular space. High-voltage electron microscopic studies of the chick embryo cornea and tendon suggested that the extracellular space is compartmentalized by the fibroblasts for the regulation of collagen fibril, bundle, and tissue specific macroaggregate formation. The purpose of this study is to gather direct evidence regarding the association of the fibroblast cell surface with newly formed collagen fibrils, and to define the role of the fibroblast in the control and the precise positioning of collagen fibrils, bundles, and macroaggregates during chick tendon development.

scholarly journals Role of endocannabinoid CB1 receptors in Streptozotocin-induced uninephrectomised Wistar rats in diabetic nephropathy

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Jayarami Reddy Medapati ◽  
Deepthi Rapaka ◽  
Veera Raghavulu Bitra ◽  
Santhosh Kumar Ranajit ◽  
Girija Sankar Guntuku ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Morphological Changes ◽  
Serum Levels ◽  
Cb1 Receptors ◽  
Protective Effects ◽  
Renal Hypertrophy ◽  
Necrosis Factor Alpha

Abstract Background The endocannabinoid CB1 receptor is known to have protective effects in kidney disease. The aim of the present study is to evaluate the potential agonistic and antagonistic actions and to determine the renoprotective potential of CB1 receptors in diabetic nephropathy. The present work investigates the possible role of CB1 receptors in the pathogenesis of diabetes-induced nephropathy. Streptozotocin (STZ) (55 mg/kg, i.p., once) is administered to uninephrectomised rats for induction of experimental diabetes mellitus. The CB1 agonist (oleamide) and CB1 antagonist (AM6545) treatment were initiated in diabetic rats after 1 week of STZ administration and were given for 24 weeks. Results The progress in diabetic nephropathy is estimated biochemically by measuring serum creatinine (1.28±0.03) (p < 0.005), blood urea nitrogen (67.6± 2.10) (p < 0.001), urinary microprotein (74.62± 3.47) (p < 0.005) and urinary albuminuria (28.31±1.17) (p < 0.0001). Renal inflammation was assessed by estimating serum levels of tumor necrosis factor alpha (75.69±1.51) (p < 0.001) and transforming growth factor beta (8.73±0.31) (p < 0.001). Renal morphological changes were assessed by estimating renal hypertrophy (7.38± 0.26) (p < 0.005) and renal collagen content (10.42± 0.48) (p < 0.001). Conclusions From the above findings, it can be said that diabetes-induced nephropathy may be associated with overexpression of CB1 receptors and blockade of CB1 receptors might be beneficial in ameliorating the diabetes-induced nephropathy. Graphical abstract

scholarly journals Dysregulation of protein kinase C in adult depression and suicide: evidence from postmortem brain studies

2021 ◽  
Author(s):  
Ghanshyam N Pandey ◽  
Anuradha Sharma ◽  
Hooriyah S Rizavi ◽  
Xinguo Ren
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Protein Expression ◽  
Mrna Expression ◽  
Postmortem Brain ◽  
Cortical Region ◽  
Cytosol Fraction ◽  
Kinase C ◽  
Pkc Isozymes

Abstract Background Several lines of evidence suggest the abnormalities of protein kinase C (PKC) signaling system in mood disorders and suicide based primarily on the studies of PKC and its isozymes in the platelets and postmortem brain of depressed and suicidal subjects. In this study we examined the role of PKC isozymes in depression and suicide. Methods We determined the protein and mRNA expression of various PKC isozymes in the prefrontal cortical region [Brodmann area 9 (BA9)] in 24 normal control (NC) subjects, 24 depressed suicide (DS) subjects and 12 depressed non-suicide (DNS) subjects. The levels of mRNA in the prefrontal cortex (PFC) were determined by qRT-PCR and the protein expression was determined by Western blotting. Results We observed a significant decrease in mRNA expression of PKCα, PKCβI, PKCδ and PKCε and decreased protein expression either in the membrane or the cytosol fraction of PKC isozymes - PKCα, PKCβI, PKCβII and PKCδ in DS and DNS subjects compared with NC subjects. Conclusions The current study provides detailed evidence of specific dysregulation of certain PKC isozymes in the postmortem brain of DS and DNS subjects and further supports earlier evidence for the role of PKC in the platelets and brain of adult and teenage depressed and suicidal population. This comprehensive study may lead to further knowledge of the involvement of PKC in the pathophysiology of depression and suicide.

Tissue Ki67 proliferative index expression and pathological changes in hemodialysis arteriovenous fistulae: Preliminary single-center results

2021 ◽  
pp. 112972982110154
Author(s):  
Raffaella Mauro ◽  
Cristina Rocchi ◽  
Francesco Vasuri ◽  
Alessia Pini ◽  
Anna Laura Croci Chiocchini ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Hot Spot ◽  
Wall Thickening ◽  
Proliferating Cells ◽  
Ki 67 ◽  
Group A ◽  
The Mean ◽  
Set Up ◽  
Group B

Background: Arteriovenous fistula (AVF) for hemodialysis integrates outward remodeling with vessel wall thickening in response to drastic hemodynamic changes. Aim of this study is to determine the role of Ki67, a well-established proliferative marker, related to AVF, and its relationship with time-dependent histological morphologic changes. Materials and methods: All patients were enrolled in 1 year and stratified in two groups: (A) pre-dialysis patients submitted to first AVF and (B) patients submitted to revision of AVF. Morphological changes: neo-angiogenesis (NAG), myointimal thickening (MIT), inflammatory infiltrate (IT), and aneurysmatic fistula degeneration (AD). The time of AVF creation was recorded. A biopsy of native vein in Group A and of arterialized vein in Group B was submitted to histological and immunohistochemical (IHC) analysis. IHC for Ki67 was automatically performed in all specimens. Ki67 immunoreactivity was assessed as the mean number of positive cells on several high-power fields, counted in the hot spots. Results: A total of 138 patients were enrolled, 69 (50.0%) Group A and 69 (50.0%) Group B. No NAG or MIT were found in Group A. Seven (10.1%) Group A veins showed a mild MIT. Analyzing the Group B, a moderate-to-severe MIT was present in 35 (50.7%), IT in 19 (27.5%), NAG in 37 (53.6%); AD was present in 10 (14.5%). All AVF of Group B with the exception of one (1.4%) showed a positivity for Ki67, with a mean of 12.31 ± 13.79 positive cells/hot spot (range 0–65). Ki67-immunoreactive cells had a subendothelial localization in 23 (33.3%) cases, a myointimal localization in SMC in 35 (50.7%) cases. The number of positive cells was significantly correlated with subendothelial localization of Ki67 ( p = 0.001) and with NA ( p = 0.001). Conclusions: Native veins do not contain cycling cells. In contrast, vascular cell proliferation starts immediately after AVF creation and persists independently of the time the fistula is set up. The amount of proliferating cells is significantly associated with MIT and subendothelial localization of Ki67-immunoreactive cells, thus suggesting a role of Ki-67 index in predicting AVF failure.

scholarly journals Membrane-associated phase separation: organization and function emerge from a two-dimensional milieu

2021 ◽  
Author(s):  
Jonathon A Ditlev
Keyword(s):  
Phase Separation ◽  
Cell Biology ◽  
Cellular Environment ◽  
Condensate Formation ◽  
Associated Proteins ◽  
Available Technology ◽  
And Function ◽  
Surrounding Membrane

Abstract Liquid‒liquid phase separation (LLPS) of biomolecules has emerged as an important mechanism that contributes to cellular organization. Phase separated biomolecular condensates, or membrane-less organelles, are compartments composed of specific biomolecules without a surrounding membrane in the nucleus and cytoplasm. LLPS also occurs at membranes, where both lipids and membrane-associated proteins can de-mix to form phase separated compartments. Investigation of these membrane-associated condensates using in vitro biochemical reconstitution and cell biology has provided key insights into the role of phase separation in membrane domain formation and function. However, these studies have generally been limited by available technology to study LLPS on model membranes and the complex cellular environment that regulates condensate formation, composition, and function. Here, I briefly review our current understanding of membrane-associated condensates, establish why LLPS can be advantageous for certain membrane-associated condensates, and offer a perspective for how these condensates may be studied in the future.

scholarly journals The Neuroinflammatory Role of Pericytes in Epilepsy

Biomedicines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 759
Author(s):  
Gaku Yamanaka ◽  
Fuyuko Takata ◽  
Yasufumi Kataoka ◽  
Kanako Kanou ◽  
Shinichiro Morichi ◽  
...  
Keyword(s):  
Proinflammatory Cytokines ◽  
Current Knowledge ◽  
Morphological Changes ◽  
Cell Damage ◽  
Neurovascular Unit ◽  
Experimental Studies ◽  
Intractable Epilepsy ◽  
In Vivo Studies

Pericytes are a component of the blood–brain barrier (BBB) neurovascular unit, in which they play a crucial role in BBB integrity and are also implicated in neuroinflammation. The association between pericytes, BBB dysfunction, and the pathophysiology of epilepsy has been investigated, and links between epilepsy and pericytes have been identified. Here, we review current knowledge about the role of pericytes in epilepsy. Clinical evidence has shown an accumulation of pericytes with altered morphology in the cerebral vascular territories of patients with intractable epilepsy. In vitro, proinflammatory cytokines, including IL-1β, TNFα, and IL-6, cause morphological changes in human-derived pericytes, where IL-6 leads to cell damage. Experimental studies using epileptic animal models have shown that cerebrovascular pericytes undergo redistribution and remodeling, potentially contributing to BBB permeability. These series of pericyte-related modifications are promoted by proinflammatory cytokines, of which the most pronounced alterations are caused by IL-1β, a cytokine involved in the pathogenesis of epilepsy. Furthermore, the pericyte-glial scarring process in leaky capillaries was detected in the hippocampus during seizure progression. In addition, pericytes respond more sensitively to proinflammatory cytokines than microglia and can also activate microglia. Thus, pericytes may function as sensors of the inflammatory response. Finally, both in vitro and in vivo studies have highlighted the potential of pericytes as a therapeutic target for seizure disorders.

scholarly journals The (Patho)Biology of SRC Kinase in Platelets and Megakaryocytes

Medicina ◽  
2020 ◽  
Vol 56 (12) ◽  
pp. 633
Author(s):  
Lore De Kock ◽  
Kathleen Freson
Keyword(s):  
Platelet Activation ◽  
Knockout Mice ◽  
Missense Variant ◽  
Surface Receptors ◽  
Src Signaling ◽  
Normal Platelet ◽  
Fibrinogen Binding ◽  
Cellular Environment ◽  
Proplatelet Formation

Proto-oncogene tyrosine-protein kinase SRC (SRC), as other members of the SRC family kinases (SFK), plays an important role in regulating signal transduction by different cell surface receptors after changes in the cellular environment. Here, we reviewed the role of SRC in platelets and megakaryocytes (MK). In platelets, inactive closed SRC is coupled to the β subunit of integrin αIIbβ3 while upon fibrinogen binding during platelet activation, αIIbβ3-mediated outside-in signaling is initiated by activation of SRC. Active open SRC now further stimulates many downstream effectors via tyrosine phosphorylation of enzymes, adaptors, and especially cytoskeletal components. Functional platelet studies using SRC knockout mice or broad spectrum SFK inhibitors pointed out that SRC mediates their spreading on fibrinogen. On the other hand, an activating pathological SRC missense variant E527K in humans that causes bleeding inhibits collagen-induced platelet activation while stimulating platelet spreading. The role of SRC in megakaryopoiesis is much less studied. SRC knockout mice have a normal platelet count though studies with SFK inhibitors point out that SRC could interfere with MK polyploidization and proplatelet formation but these inhibitors are not specific. Patients with the SRC E527K variant have thrombocytopenia due to hyperactive SRC that inhibits proplatelet formation after increased spreading of MK on fibrinogen and enhanced formation of podosomes. Studies in humans have contributed significantly to our understanding of SRC signaling in platelets and MK.

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