scholarly journals The role of the integrated stress response in keratinocyte migration

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Jennifer Hartman ◽  
Miguel Barriera Diaz ◽  
Ronald C. Wek ◽  
Dan F. Spandau

Background and Hypothesis: Cutaneous wound healing involves: hemostatic, inflammatory, proliferative, and tissue remodeling phases. Re-epithelialization can be modeled in vitro using human keratinocytes and artificial wounds. Previous work showed undifferentiated keratinocytes closing wounds in vitro using individual cell migration (ICM), whilst differentiated keratinocytes utilize collective cell migration (KCCM). Therefore, we hypothesize that ICM in vitro is equivalent to keratinocyte migration during squamous cell carcinoma metastasis in vivo and KCCM is a model for wound re-epithelialization. Furthermore, we hypothesize that the integrated stress response (ISR) is important in ICM and KCCM. The ISR is activated by environmental stresses that protein kinases (GCN2 and PERK) can detect and phosphorylate translation factor, eIF2a. Our goal is to define how the ISR, specifically GCN2 and PERK, influence keratinocyte migration. Methods: We will evaluate in vitro wound healing and kinetic variation in protein expression and cytoskeleton remodeling. We will utilize four keratinocyte cell lines, control human keratinocyte NTERTs, and CRISPR-derived gene knockouts of GCN2, PERK, and ISR effector gene ATF4. Quantitative analysis of wound healing is accomplished using an IncuCyte ZOOM instrument. Protein expression is measured via immunoblots following high density wounding. Cytoskeletal analyses was done by immunofluorescence. Results: Preliminary results show PERK-KO and GCN2-KO cells have reduced expression of F-actin. Immunoblots showed actin-binding protein, phospho-cofilin, at lower levels in PERK-KO and GCN2-KO cells than in NTERT cells. Wound healing assays showed differentiated keratinocytes healing faster than undifferentiated in all cells, except GCN2-KO. GCN2-KO cells healed significantly slower than other differentiated cells and undifferentiated GCN2-KO cells. Wound healing assays showed undifferentiated PERK-KO cells healing slower than other undifferentiated cell lines. Conclusion/Potential Impact: The results indicate PERK and GCN2 could be key components in ICM and CCM respectfully. GCN2 and PERK could thus be potential therapeutic targets to provide cost-effective therapeutics to enhance/inhibit keratinocyte migration.

2009 ◽  
Vol 38 (3) ◽  
pp. 372-385 ◽  
Author(s):  
Han Zhang ◽  
Xunsheng Chen ◽  
Wendy B. Bollag ◽  
Roni J. Bollag ◽  
Daniel J. Sheehan ◽  
...  

Lasp1 is an actin-binding, signaling pathway-regulated phosphoprotein that is overexpressed in several cancers. siRNA knockdown in cell lines retards cell migration, suggesting the possibility that Lasp1 upregulation influences cancer metastasis. Herein, we utilized a recently developed gene knockout model to assess the role of Lasp1 in modulating nontransformed cell functions. Wound healing and tumor initiation progressed more rapidly in Lasp1−/− mice compared with Lasp1+/+ controls. Embryonic fibroblasts (MEFs) derived from Lasp1−/− mice also migrated more rapidly in vitro. These MEFs characteristically possessed increased focal adhesion numbers and displayed more rapid attachment compared with wild-type MEFs. Differential microarray analyses revealed alterations in message expression for proteins implicated in cell migration, adhesion, and cytoskeletal organization. Notably, the focal adhesion protein, lipoma preferred partner (LPP), a zyxin family member and putative Lasp1 binding protein, was increased about twofold. Because LPP gene disruption reduces cell migration, we hypothesize that LPP plays a role in enhancing the migratory capacity of Lasp1−/− MEFs, perhaps by modifying the subcellular localization of other motility-associated proteins. The striking contrast in the functional effects of loss of Lasp1 in innate cells compared with cell lines reveals distinct differences in mechanisms of motility and attachment in these models.


Physiology ◽  
2013 ◽  
Vol 28 (6) ◽  
pp. 370-379 ◽  
Author(s):  
Sri Ram Krishna Vedula ◽  
Andrea Ravasio ◽  
Chwee Teck Lim ◽  
Benoit Ladoux

Collective cell migration is fundamental to gaining insights into various important biological processes such as wound healing and cancer metastasis. In particular, recent in vitro studies and in silico simulations suggest that mechanics can explain the social behavior of multicellular clusters to a large extent with minimal knowledge of various cellular signaling pathways. These results suggest that a mechanistic perspective is necessary for a comprehensive and holistic understanding of collective cell migration, and this review aims to provide a broad overview of such a perspective.


2011 ◽  
Vol 89 (6) ◽  
pp. 393-400 ◽  
Author(s):  
Carly Lodewyks ◽  
Jose Rodriguez ◽  
Jing Yan ◽  
Betty Lerner ◽  
Jeremy Lipschitz ◽  
...  

There are conflicting data regarding whether activation of γ-aminobutyric acid-B (GABA-B) receptors results in inhibition of tumor growth and invasion. The objectives of this study were to document the effects of the GABA-B receptor agonist baclofen on malignant hepatocyte proliferation and migration. We also sought to determine whether any effects on cell migration were mediated by changes in cyclic adenosine monophosphate (cAMP) signaling or matrix metalloproteinase (MMP) expression. Finally, GABA-B1 and -B2 receptor expression was documented in 2 malignant hepatocyte cell lines (PLC/PRF/5 and Huh-7) and 12 sets of human hepatocellular carcinoma and adjacent nontumor tissues. Cell proliferative activity was documented by WST-1 absorbance, migration by wound healing assays, cAMP levels by enzyme-linked immunoassay (ELISA), MMP by immunohistochemistry and ELISA, and GABA-B receptor expression by flow cytometry and reverse transcriptase – polymerase chain reaction. Although baclofen had no effect on cell proliferation, wound healing was delayed, an effect that was reversed by the GABA-B receptor antagonist CGP. cAMP levels were decreased in Huh-7 but not PLC cells exposed to baclofen. MMP expression remained unaltered in both cell lines. Finally, GABA-B1 receptor expression was present and consistently expressed, but GABA-B2 expression was limited and varied with the number of cell passages and (or) duration of culture. In conclusion, activation of GABA-B receptors has no effect on malignant hepatocyte proliferation but does decrease cell migration. This inhibitory effect may involve cAMP signaling but not MMP expression. GABA-B2 receptor expression is limited and variable, which may help to explain discrepancies with previously published results.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ai-Ling Tian ◽  
Qi Wu ◽  
Peng Liu ◽  
Liwei Zhao ◽  
Isabelle Martins ◽  
...  

AbstractThe integrated stress response manifests with the phosphorylation of eukaryotic initiation factor 2α (eIF2α) on serine residue 51 and plays a major role in the adaptation of cells to endoplasmic reticulum stress in the initiation of autophagy and in the ignition of immune responses. Here, we report that lysosomotropic agents, including azithromycin, chloroquine, and hydroxychloroquine, can trigger eIF2α phosphorylation in vitro (in cultured human cells) and, as validated for hydroxychloroquine, in vivo (in mice). Cells bearing a non-phosphorylatable eIF2α mutant (S51A) failed to accumulate autophagic puncta in response to azithromycin, chloroquine, and hydroxychloroquine. Conversely, two inhibitors of eIF2α dephosphorylation, nelfinavir and salubrinal, enhanced the induction of such autophagic puncta. Altogether, these results point to the unexpected capacity of azithromycin, chloroquine, and hydroxychloroquine to elicit the integrated stress response.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yoshifumi Asakura ◽  
Yohei Kondo ◽  
Kazuhiro Aoki ◽  
Honda Naoki

AbstractCollective cell migration is a fundamental process in embryonic development and tissue homeostasis. This is a macroscopic population-level phenomenon that emerges across hierarchy from microscopic cell-cell interactions; however, the underlying mechanism remains unclear. Here, we addressed this issue by focusing on epithelial collective cell migration, driven by the mechanical force regulated by chemical signals of traveling ERK activation waves, observed in wound healing. We propose a hierarchical mathematical framework for understanding how cells are orchestrated through mechanochemical cell-cell interaction. In this framework, we mathematically transformed a particle-based model at the cellular level into a continuum model at the tissue level. The continuum model described relationships between cell migration and mechanochemical variables, namely, ERK activity gradients, cell density, and velocity field, which could be compared with live-cell imaging data. Through numerical simulations, the continuum model recapitulated the ERK wave-induced collective cell migration in wound healing. We also numerically confirmed a consistency between these two models. Thus, our hierarchical approach offers a new theoretical platform to reveal a causality between macroscopic tissue-level and microscopic cellular-level phenomena. Furthermore, our model is also capable of deriving a theoretical insight on both of mechanical and chemical signals, in the causality of tissue and cellular dynamics.


2021 ◽  
Vol 20 ◽  
pp. 153303382098011
Author(s):  
Junjun Shu ◽  
Ling Xiao ◽  
Sanhua Yan ◽  
Boqun Fan ◽  
Xia Zou ◽  
...  

Objective: Ovarian cancer (OC) ranks one of the most prevalent fatal tumors of female genital organs. Aberrant promoter methylation triggers changes of microRNA (miR)-375 in OC. Our study aimed to evaluate the mechanism of methylated miR-375 promoter region in OC cell malignancy and to seek the possible treatment for OC. Methods: miR-375 promoter methylation level in OC tissues and cells was detected. miR-375 expression in OC tissues and cell lines was compared with that in demethylated cells. Role of miR-375 in OC progression was measured. Dual-luciferase reporter gene assay was utilized to verify the targeting relationship between miR-375 and Yes-associated protein 1 (YAP1). Then, Wnt/β-catenin pathway-related protein expression was tested. Moreover, xenograft transplantation was applied to confirm the in vitro experiments. Results: Highly methylated miR-375 was seen in OC tissues and cell lines, while its expression was decreased as the promoter methylation increased. Demethylation in OC cells brought miR-375 back to normal level, with obviously declined cell invasion, migration and viability and improved apoptosis. Additionally, miR-375 targeted YAP1 to regulate the Wnt/β-catenin pathway protein expression. Overexpressed YAP1 reversed the protein expression, promoted cell invasion, migration and viability while reduced cell apoptosis. Overexpressed miR-375 in vivo inhibited OC progression. Conclusion: Our study demonstrated that demethylated miR-375 inhibited OC growth by targeting YAP1 and downregulating the Wnt/β-catenin pathway. This investigation may offer novel insight for OC treatment.


Author(s):  
Gil Topman ◽  
Orna Sharabani-Yosef ◽  
Amit Gefen

A wound healing assay is simple but effective method to study cell migration in vitro. Cell migration in vitro was found to mimic migration in vivo to some extent [1,2]. In wound healing assays, a “wound” is created by either scraping or mechanically crushing cells in a monolayer, thereby forming a denuded area. Cells migrate into the denuded area to complete coverage, and thereby “heal” the wound. Micrographs at regular time intervals are captured during such experiments for analysis of the process of migration.


Development ◽  
2021 ◽  
Vol 148 (7) ◽  
pp. dev191767
Author(s):  
Jessica Stock ◽  
Andrea Pauli

ABSTRACTSelf-organization is a key feature of many biological and developmental processes, including cell migration. Although cell migration has traditionally been viewed as a biological response to extrinsic signals, advances within the past two decades have highlighted the importance of intrinsic self-organizing properties to direct cell migration on multiple scales. In this Review, we will explore self-organizing mechanisms that lay the foundation for both single and collective cell migration. Based on in vitro and in vivo examples, we will discuss theoretical concepts that underlie the persistent migration of single cells in the absence of directional guidance cues, and the formation of an autonomous cell collective that drives coordinated migration. Finally, we highlight the general implications of self-organizing principles guiding cell migration for biological and medical research.


1970 ◽  
Vol 7 (3) ◽  
pp. 14-19 ◽  
Author(s):  
Hekdin Marsius Sipayung ◽  
Jansen Silalahi ◽  
Yuandani Y

Objectives: The objective of this study was to investigate the activity of combination of hydrolyzed VCO (HVCO) and chitosan on NIH 3T3 cell proliferation activity, NIH 3T3 cell migration, COX-2 and VEGF protein expression. Design: In vitro cytotoxic assay was determined by MTT (MicrocultureTetrazoliumTehnique) assay, cell proliferation activity was measured by calculating cell viability incubated 24 hours, 48 hours and 72 hours, wound closure percentage was tested by scratch wound healing method, expression of COX-2 protein and VEGF protein were measured by immunocytochemical method. Interventions: The variable that was intervened in this study was the concentration of HVCO and chitosan. Main Outcome Measures: The main measurements carried out in this study were the absorbance value of HVCO and chitosan which was converted into viability cell, proliferation activity, percentage of wound closure, and percentage of COX-2 and VEGF protein expression. Results: Cytotoxic activity of HVCO and chitosan resulted the best concentration at 31.25 μg/ml, scratch wound healing assay from a combination HVCO and chitosan resulted the best migration of fibroblast cells at a ratio of 1:1 with HVCO 62.5 μg/ml and chitosan 62.5 μg/ml, combination of HVCO 62.5 μg/ml and chitosan 62.5 μg/ml (1:1) increased expression of COX-2 and VEGF. Conclusion: Combination of HVCO and chitosan could increase NIH 3T3 cell migration, COX-2 and VEGF protein expression. Combination of HVCO and chitosan had better wound healing activity in vitro than single use. Keywords: Rhizomucor miehei, viability, proliferation, migration, expression


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