scholarly journals Dynamic filopodia are required for chemokine-dependent intracellular polarization during guided cell migration in vivo

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Dana Meyen ◽  
Katsiaryna Tarbashevich ◽  
Torsten U Banisch ◽  
Carolina Wittwer ◽  
Michal Reichman-Fried ◽  
...  

Cell migration and polarization is controlled by signals in the environment. Migrating cells typically form filopodia that extend from the cell surface, but the precise function of these structures in cell polarization and guided migration is poorly understood. Using the in vivo model of zebrafish primordial germ cells for studying chemokine-directed single cell migration, we show that filopodia distribution and their dynamics are dictated by the gradient of the chemokine Cxcl12a. By specifically interfering with filopodia formation, we demonstrate for the first time that these protrusions play an important role in cell polarization by Cxcl12a, as manifested by elevation of intracellular pH and Rac1 activity at the cell front. The establishment of this polarity is at the basis of effective cell migration towards the target. Together, we show that filopodia allow the interpretation of the chemotactic gradient in vivo by directing single-cell polarization in response to the guidance cue.

2021 ◽  
Vol 118 (7) ◽  
pp. e2018480118
Author(s):  
Adan Olguin-Olguin ◽  
Anne Aalto ◽  
Benoît Maugis ◽  
Aleix Boquet-Pujadas ◽  
Dennis Hoffmann ◽  
...  

To study the mechanisms controlling front-rear polarity in migrating cells, we used zebrafish primordial germ cells (PGCs) as an in vivo model. We find that polarity of bleb-driven migrating cells can be initiated at the cell front, as manifested by actin accumulation at the future leading edge and myosin-dependent retrograde actin flow toward the other side of the cell. In such cases, the definition of the cell front, from which bleb-inhibiting proteins such as Ezrin are depleted, precedes the establishment of the cell rear, where those proteins accumulate. Conversely, following cell division, the accumulation of Ezrin at the cleavage plane is the first sign for cell polarity and this aspect of the cell becomes the cell back. Together, the antagonistic interactions between the cell front and back lead to a robust polarization of the cell. Furthermore, we show that chemokine signaling can bias the establishment of the front-rear axis of the cell, thereby guiding the migrating cells toward sites of higher levels of the attractant. We compare these results to a theoretical model according to which a critical value of actin treadmilling flow can initiate a positive feedback loop that leads to the generation of the front-rear axis and to stable cell polarization. Together, our in vivo findings and the mathematical model, provide an explanation for the observed nonoriented migration of primordial germ cells in the absence of the guidance cue, as well as for the directed migration toward the region where the gonad develops.


2019 ◽  
Author(s):  
Adan Olguin-Olguin ◽  
Anne Aalto ◽  
Benoît Maugis ◽  
Michal Reichman-Fried ◽  
Erez Raz

The mechanisms facilitating the establishment of front-rear polarity in migrating cells are not fully understood, in particular in the context of bleb-driven directional migration. To gain further insight into this issue we utilized the migration of zebrafish primordial germ cells (PGCs) as an in vivo model. We followed the molecular and morphological cascade that converts apolar cells into polarized bleb-forming motile cells and analyzed the cross dependency among the different cellular functions we identified. Our results underline the critical role of antagonistic interactions between the front and the rear, in particular the role of biophysical processes including formation of barriers and transport of specific proteins to the back of the cell. These interactions direct the formation of blebs to a specific part of the cell that is specified as the cell front. In this way, spontaneous cell polarization facilitates non-directional cell motility and when biased by chemokine signals leads to migration towards specific locations.


Author(s):  
Anne Aalto ◽  
Adan Olguin-Olguin ◽  
Erez Raz

Similar to many other organisms, zebrafish primordial germ cells (PGCs) are specified at a location distinct from that of gonadal somatic cells. Guided by chemotactic cues, PGCs migrate through embryonic tissues toward the region where the gonad develops. In this process, PGCs employ a bleb-driven amoeboid migration mode, characterized by low adhesion and high actomyosin contractility, a strategy used by other migrating cells, such as leukocytes and certain types of cancer cells. The mechanisms underlying the motility and the directed migration of PGCs should be robust to ensure arrival at the target, thereby contributing to the fertility of the organism. These features make PGCs an excellent model for studying guided single-cell migration in vivo. In this review, we present recent findings regarding the establishment and maintenance of cell polarity that are essential for motility and discuss the mechanisms by which cell polarization and directed migration are controlled by chemical and physical cues.


Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 8 ◽  
Author(s):  
Mayra Antúnez-Mojica ◽  
Andrés Rojas-Sepúlveda ◽  
Mario Mendieta-Serrano ◽  
Leticia Gonzalez-Maya ◽  
Silvia Marquina ◽  
...  

By using a zebrafish embryo model to guide the chromatographic fractionation of antimitotic secondary metabolites, seven podophyllotoxin-type lignans were isolated from a hydroalcoholic extract obtained from the steam bark of Bursera fagaroides. The compounds were identified as podophyllotoxin (1), β-peltatin-A-methylether (2), 5′-desmethoxy-β-peltatin-A-methylether (3), desmethoxy-yatein (4), desoxypodophyllotoxin (5), burseranin (6), and acetyl podophyllotoxin (7). The biological effects on mitosis, cell migration, and microtubule cytoskeleton remodeling of lignans 1–7 were further evaluated in zebrafish embryos by whole-mount immunolocalization of the mitotic marker phospho-histone H3 and by a tubulin antibody. We found that lignans 1, 2, 4, and 7 induced mitotic arrest, delayed cell migration, and disrupted the microtubule cytoskeleton in zebrafish embryos. Furthermore, microtubule cytoskeleton destabilization was observed also in PC3 cells, except for 7. Therefore, these results demonstrate that the cytotoxic activity of 1, 2, and 4 is mediated by their microtubule-destabilizing activity. In general, the in vivo and in vitro models here used displayed equivalent mitotic effects, which allows us to conclude that the zebrafish model can be a fast and cheap in vivo model that can be used to identify antimitotic natural products through bioassay-guided fractionation.


Development ◽  
1995 ◽  
Vol 121 (11) ◽  
pp. 3495-3503 ◽  
Author(s):  
M.K. Jaglarz ◽  
K.R. Howard

We describe our analysis of primordial germ cell migration in Drosophila wild-type and mutant embryos using high resolution microscopy and primary culture in vitro. During migratory events the germ cells form transient interactions with each other and surrounding somatic cells. Both in vivo and in vitro they extend pseudopodia and the accompanying changes in the cytoskeleton suggest that actin polymerization drives these movements. These cellular events occur from the end of the blastoderm stage and are regulated by environmental cues. We show that the vital transepithelial migration allowing exit from the gut primordium and passage into the interior of the embryo is facilitated by changes in the structure of this epithelium. Migrating germ cells extend processes in different directions. This phenomenon also occurs in primary culture where the cells move in an unoriented fashion at substratum concentration-dependent rates. In vivo this migration is oriented leading germ cells to the gonadal mesoderm. We suggest that this guidance involves stabilization of states of an intrinsic cellular oscillator resulting in cell polarization and oriented movement.


2020 ◽  
Vol 124 (1) ◽  
pp. 161-165
Author(s):  
Nidhi Pamidimukkala ◽  
Gemma S. Puts ◽  
M. Kathryn Leonard ◽  
Devin Snyder ◽  
Sandrine Dabernat ◽  
...  

AbstractNME1 is a metastasis-suppressor gene (MSG), capable of suppressing metastatic activity in cell lines of melanoma, breast carcinoma and other cancer origins without affecting their growth in culture or as primary tumours. Herein, we selectively ablated the tandemly arranged Nme1 and Nme2 genes to assess their individual impacts on metastatic activity in a mouse model (HGF:p16−/−) of ultraviolet radiation (UVR)-induced melanoma. Metastatic activity was strongly enhanced in both genders of Nme1- and Nme2-null mice, with stronger activity in females across all genotypes. The study ascribes MSG activity to Nme2 for the first time in an in vivo model of spontaneous cancer, as well as a novel metastasis-suppressor function to Nme1 in the specific context of UVR-induced melanoma.


2009 ◽  
Vol 296 (5) ◽  
pp. R1650-R1660 ◽  
Author(s):  
Yi-Fang Wang ◽  
Yung-Che Tseng ◽  
Jia-Jiun Yan ◽  
Junya Hiroi ◽  
Pung-Pung Hwang

The thiazide-sensitive Na+-Cl− cotransporter (NCC), a member of the SLC12 family, is mainly expressed in the apical membrane of the mammalian distal convoluted tubule (DCT) cells, is responsible for cotransporting Na+ and Cl− from the lumen into DCT cells and plays a major role in the mammalian renal NaCl reabsorption. The NCC has also been reported in fish, but the functional role in fish ion regulation is yet unclear. The present study used zebrafish as an in vivo model to test the hypothesis of whether the NCC plays a role in Na+ and/or Cl− uptake mechanisms. Four NCCs were cloned, and only one of them, zebrafish (z) slc12a10.2 was found to predominately and specifically be expressed in gills. Double in situ hybridization/immunocytochemistry in zebrafish skin/gills demonstrated that the specific expression of zslc12a10.2 mRNA in a novel group of ionocytes differed from those of the previously-reported H+-ATPase-rich (HR) cells and Na+-K+-ATPase-rich (NaR) cells. Gill mRNA expression of zslc12a10.2 was induced by a low-Cl environment that stimulated fish Cl− influx, while a low-Na environment suppressed this expression. Incubation with metolazone, a specific inhibitor of the NCC, impaired both Na+ and Cl− influx in 5-day postfertilization (dpf) zebrafish embryos. Translational knockdown of zslc12a10.2 with a specific morpholino caused significant decreases in both Cl− influx and Cl− content of 5-dpf zebrafish embryos, suggesting that the operation of zNCC-like 2 results in a net uptake of Cl− in zebrafish. On the contrary, zslc12a10.2 morphants showed increased Na+ influx and content that resulted from upregulation of mRNA expressions of Na+-H+ exchanger 3b and carbonic anhydrase 15a in HR cells. These results for the first time provide in vivo molecular physiological evidence for the possible role of the NCC in the Cl− uptake mechanism in zebrafish skin/gills.


2015 ◽  
Author(s):  
Andrzej Jerzy Rzepiela ◽  
Arnau Vina-Vilaseca ◽  
Jeremie Breda ◽  
Souvik Ghosh ◽  
Afzal P Syed ◽  
...  

MiRNAs are post-transcriptional repressors of gene expression that may additionally reduce the cell-to-cell variability in protein expression, induce correlations between target expression levels and provide a layer through which targets can influence each other's expression as 'competing RNAs' (ceRNAs). Here we combined single cell sequencing of human embryonic kidney cells in which the expression of two distinct miRNAs was induced over a wide range, with mathematical modeling, to estimate Michaelis-Menten (KM)-type constants for hundreds of evolutionarily conserved miRNA targets. These parameters, which we inferred here for the first time in the context of the entire network of endogenous miRNA targets, vary over ~2 orders of magnitude. They reveal an in vivo hierarchy of miRNA targets, defined by the concentration of miRNA-Argonaute complexes at which the targets are most sensitively down-regulated. The data further reveals miRNA-induced correlations in target expression at the single cell level, as well as the response of target noise to the miRNA concentration. The approach is generalizable to other miRNAs and post-transcriptional regulators and provides a deeper understanding of gene expression dynamics.


2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi249-vi250
Author(s):  
Thuvarahan Jegathees ◽  
Victoria Prior ◽  
Geraldine O’Neill

Abstract A major limitation in the treatment of High Grade Gliomas (HGG) is their highly disseminating nature. While it is increasingly appreciated that the mechanical properties of the extracellular matrix, (measured as tissue elasticity, Young’s modulus, E), can independently cue cancer cell migration and invasion, to date there has been little consideration of this mechanism in HGG invasion. This is particularly important given that the brain parenchyma is a mechanically soft tissue (E values varying between 1 - 10 kPa). By measuring single cell migration we have previously demonstrated that molecular subclasses of HGGs exhibit different rigidity-sensitive and -insensitive migration. Following these findings, the present project aimed to determine whether these mechanosensitive phenotypes are maintained in the dissemination of multicellular tumour spheroids (MCTSs) that represent in vivo organisation of the primary tumour bulk. Therefore MCTSs composed of primary patient-derived HGG cells with pre-established single cell mechanosensitive phenotypes were cultured on mechanically tuneable polyacrylamide hydrogels, mimicking the range of physiological tissue rigidities. Bright-field time-lapse images were then captured over a period of 48 hours, 6 images per hour. In order to quantitate the migratory behaviours, we adapted a previously published automated image analysis program to segment the MCTS images into proliferative and migratory regions. Our analysis suggests that the cellular mechano-phenotype is affected by contact with neighbouring cells, as the migratory response to tissue stiffness is quantitatively different in the MCTSs. Our results highlight different migratory behaviour between HGG cells within the primary tumour mass versus individual cells that escape. Our results reveal the complex migratory behaviour of HGG cells and suggests that successful anti-invasive therapies will need different strategies depending on tumour cell location.


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