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1.
J Biomed Opt ; 29(7): 076002, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38966847

ABSTRACT

Significance: Optical coherence tomography has great utility for capturing dynamic processes, but such applications are particularly data-intensive. Samples such as biological tissues exhibit temporal features at varying time scales, which makes data reduction challenging. Aim: We propose a method for capturing short- and long-term correlations of a sample in a compressed way using non-uniform temporal sampling to reduce scan time and memory overhead. Approach: The proposed method separates the relative contributions of white noise, fluctuating features, and stationary features. The method is demonstrated on mammary epithelial cell spheroids in three-dimensional culture for capturing intracellular motility without loss of signal integrity. Results: Results show that the spatial patterns of motility are preserved and that hypothesis tests of spheroids treated with blebbistatin, a motor protein inhibitor, are unchanged with up to eightfold compression. Conclusions: The ability to measure short- and long-term correlations compressively will enable new applications in (3+1)D imaging and high-throughput screening.


Subject(s)
Tomography, Optical Coherence , Tomography, Optical Coherence/methods , Humans , Spheroids, Cellular/drug effects , Cell Movement/physiology , Cell Movement/drug effects , Image Processing, Computer-Assisted/methods , Epithelial Cells/drug effects , Algorithms , Heterocyclic Compounds, 4 or More Rings
2.
Reprod Fertil Dev ; 362024 Jul.
Article in English | MEDLINE | ID: mdl-38976640

ABSTRACT

Context There is mounting evidence implicating kisspeptin signalling in placental development and function. Aims This study aimed to elucidate kisspeptin's role in trophoblast invasion and migration using three experimental models. Methods First, we examined the mouse fetus and placenta in a kisspeptin receptor (Kiss1r) knockout (KO) model. Fetal/placental weights and gene expression (quantitative polymerase chain reaction) were assessed. Second, we determined kisspeptin effects on a human trophoblast (BeWo) cell line in vitro . Third, we examined KISS1 and KISS1R gene expression in human placenta from term and pre-term pregnancies. Key results No difference was found in fetal or placental weight between Kiss1r KO and wildtype mice. However, expression of the trophoblast invasion marker, Mmp2 mRNA, was greater in the placental labyrinth zone of Kiss1r KO mice. BeWo cell models of villus cytotrophoblast and syncytiotrophoblast cells exhibited kisspeptin protein expression, with greater expression in syncytiotrophoblast, consistent with KISS1 mRNA. Kisspeptin treatment inhibited the migratory potential of cytotrophoblast-like cells. Finally, while no difference was seen in KISS1 and KISS1R mRNA between term and pre-term placentas, we saw a difference in the relative expression of each gene pre-term. We also observed a positive correlation between KISS1 expression and maternal body mass index. Conclusions Our results indicate that kisspeptin may inhibit trophoblast invasion. Implications Further investigation is required to clarify specific regulatory mechanisms.


Subject(s)
Cell Movement , Kisspeptins , Mice, Knockout , Placenta , Receptors, Kisspeptin-1 , Trophoblasts , Kisspeptins/metabolism , Kisspeptins/genetics , Female , Trophoblasts/metabolism , Receptors, Kisspeptin-1/metabolism , Receptors, Kisspeptin-1/genetics , Animals , Pregnancy , Placenta/metabolism , Cell Movement/physiology , Humans , Mice , Cell Line , Placentation/physiology
3.
Med Sci (Paris) ; 40(6-7): 515-524, 2024.
Article in French | MEDLINE | ID: mdl-38986096

ABSTRACT

Invadosome is an umbrella term used to describe a family of cellular structures including podosomes and invadopodia. They serve as contact zones between the cell plasma membrane and extracellular matrix, contributing to matrix remodeling by locally enriched proteolytic enzymes. Invadosomes, which are actin-dependent, are implicated in cellular processes promoting adhesion, migration, and invasion. Invadosomes, which exist in various cell types, play crucial roles in physiological phenomena such as vascularization and bone resorption. Invadosomes are also implicated in pathological processes such as matrix tissue remodeling during metastatic tumor cell invasion. This review summarizes basic information and recent advances about mechanisms underlying podosome and invadopodia formation, their organization and function.


Title: Invadosomes - Entre mobilité et invasion, naviguer dans la dualité des fonctions cellulaires. Abstract: Le terme « invadosome ¼ désigne une famille de structures cellulaires, comprenant les podosomes et les invadopodes, qui constituent des zones de contact entre la membrane plasmique des cellules et la matrice extracellulaire. Ces structures contribuent au remodelage de la matrice grâce à un enrichissement local en enzymes protéolytiques qui dégradent ses constituants fibrillaires. Les invadosomes, présents dans des types cellulaires variés, contribuent à des processus physiologiques, tels que la vascularisation, ou pathologiques, comme l'invasion des tissus par les cellules métastatiques.


Subject(s)
Cell Movement , Extracellular Matrix , Neoplasm Invasiveness , Neoplasms , Podosomes , Humans , Podosomes/physiology , Podosomes/pathology , Cell Movement/physiology , Animals , Neoplasms/pathology , Extracellular Matrix/physiology , Extracellular Matrix/pathology
4.
Proc Natl Acad Sci U S A ; 121(30): e2410708121, 2024 Jul 23.
Article in English | MEDLINE | ID: mdl-39028692

ABSTRACT

Gliding motility proceeds with little changes in cell shape and often results from actively driven surface flows of adhesins binding to the extracellular environment. It allows for fast movement over surfaces or through tissue, especially for the eukaryotic parasites from the phylum apicomplexa, which includes the causative agents of the widespread diseases malaria and toxoplasmosis. We have developed a fully three-dimensional active particle theory which connects the self-organized, actively driven surface flow over a fixed cell shape to the resulting global motility patterns. Our analytical solutions and numerical simulations show that straight motion without rotation is unstable for simple shapes and that straight cell shapes tend to lead to pure rotations. This suggests that the curved shapes of Plasmodium sporozoites and Toxoplasma tachyzoites are evolutionary adaptations to avoid rotations without translation. Gliding motility is also used by certain myxo- or flavobacteria, which predominantly move on flat external surfaces and with higher control of cell surface flow through internal tracks. We extend our theory for these cases. We again find a competition between rotation and translation and predict the effect of internal track geometry on overall forward speed. While specific mechanisms might vary across species, in general, our geometrical theory predicts and explains the rotational, circular, and helical trajectories which are commonly observed for microgliders. Our theory could also be used to design synthetic microgliders.


Subject(s)
Cell Shape , Models, Biological , Cell Shape/physiology , Cell Movement/physiology , Toxoplasma/physiology , Plasmodium/physiology
5.
PLoS Comput Biol ; 20(7): e1012281, 2024 Jul.
Article in English | MEDLINE | ID: mdl-39038038

ABSTRACT

Capillary plexus cultivation is crucial in tissue engineering and regenerative medicine. Theoretical simulations have been conducted to supplement the expensive experimental works. However, the mechanisms connecting mechanical and chemical stimuli remained undefined, and the functions of the different VEGF forms in the culture environment were still unclear. In this paper, we developed a hybrid model for simulating short-term in vitro capillary incubations. We used the Cellular Potts model to predict individual cell migration, morphology change, and continuum mechanics to quantify biogel deformation and VEGF transport dynamics. By bridging the mechanical regulation and chemical stimulation in the model, the results showed good agreement between the predicted network topology and experiments, in which elongated cells connected, forming the network cords and round cells gathered, creating cobblestone-like aggregates. The results revealed that the capillary-like networks could develop in high integrity only when the mechanical and chemical couplings worked adequately, with the cell morphology and haptotaxis driven by the soluble and bound forms of VEGF, respectively, functioning simultaneously.


Subject(s)
Capillaries , Computer Simulation , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factor A/metabolism , Capillaries/metabolism , Humans , Cell Movement/physiology , Models, Biological , Computational Biology , Neovascularization, Physiologic/physiology , Tissue Engineering/methods
6.
Respir Res ; 25(1): 267, 2024 Jul 05.
Article in English | MEDLINE | ID: mdl-38970088

ABSTRACT

BACKGROUND: Lung cancer is the second most common cancer with the highest mortality in the world. Calumenin as a molecular chaperone that not only binds various proteins within the endoplasmic reticulum but also plays crucial roles in diverse processes associated with tumor development. However, the regulatory mechanism of calumenin in lung adenocarcinoma remains elusive. Here, we studied the impact of calumenin on lung adenocarcinoma and explored possible mechanisms. METHODS: 5-ethynyl-2'-deoxyuridine assay, colony formation, transwell and wound healing assays were performed to explore the effects of calumenin on the proliferation and migration of lung adenocarcinoma cells. To gain insights into the underlying mechanisms through which calumenin knockdown inhibits the migration and proliferation of lung adenocarcinoma, we performed Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, Gene Set Enrichment Analysis and Ingenuity Pathway Analysis based on transcriptomics by comparing calumenin knockdown with normal A549 cells. RESULTS: The mRNA and protein levels of calumenin in lung adenocarcinoma are highly expressed and they are related to an unfavorable prognosis in this disease. Calumenin enhances the proliferation and migration of A549 and H1299 cells. Gene Set Enrichment Analysis revealed that knockdown of calumenin in A549 cells significantly inhibited MYC and V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog signaling pathways while activating interferon signals, inflammatory signals, and p53 pathways. Ingenuity pathway analysis provided additional insights, indicating that the interferon and inflammatory pathways were prominently activated upon calumenin knockdown in A549 cells. CONCLUSIONS: The anti-cancer mechanism of calumenin knockdown might be related to the inhibition of MYC and KRAS signals but the activation of interferon signals, inflammatory signals and p53 pathways.


Subject(s)
Adenocarcinoma of Lung , Cell Movement , Cell Proliferation , Lung Neoplasms , Neoplasm Invasiveness , Humans , Cell Proliferation/physiology , Cell Movement/physiology , Adenocarcinoma of Lung/pathology , Adenocarcinoma of Lung/genetics , Adenocarcinoma of Lung/metabolism , Lung Neoplasms/pathology , Lung Neoplasms/metabolism , Lung Neoplasms/genetics , Disease Progression , A549 Cells , Calcium-Binding Proteins/metabolism , Calcium-Binding Proteins/genetics , Gene Expression Regulation, Neoplastic
7.
PLoS One ; 19(6): e0305491, 2024.
Article in English | MEDLINE | ID: mdl-38924026

ABSTRACT

Understanding mechanisms underlying various physiological and pathological processes often requires accurate and fully automated analysis of dense cell populations that collectively migrate. In such multicellular systems, there is a rising interest in the relations between biophysical and cell cycle progression aspects. A seminal tool that led to a leap in real-time study of cell cycle is the fluorescent ubiquitination-based cell cycle indicator (FUCCI). Here, we introduce ConfluentFUCCI, an open-source graphical user interface-based framework that is designed, unlike previous tools, for fully automated analysis of cell cycle progression, cellular dynamics, and cellular morphology, in highly dense migrating cell collectives. We integrated into ConfluentFUCCI's pipeline state-of-the-art tools such as Cellpose, TrackMate, and Napari, some of which incorporate deep learning, and we wrap the entire tool into an isolated computational environment termed container. This provides an easy installation and workflow that is independent of any specific operation system. ConfluentFUCCI offers accurate nuclear segmentation and tracking using FUCCI tags, enabling comprehensive investigation of cell cycle progression at both the tissue and single-cell levels. We compare ConfluentFUCCI to the most recent relevant tool, showcasing its accuracy and efficiency in handling large datasets. Furthermore, we demonstrate the ability of ConfluentFUCCI to monitor cell cycle transitions, dynamics, and morphology within densely packed epithelial cell populations, enabling insights into mechanotransductive regulation of cell cycle progression. The presented tool provides a robust approach for investigating cell cycle-related phenomena in complex biological systems, offering potential applications in cancer research and other fields.


Subject(s)
Cell Cycle , Cell Movement , Cell Cycle/physiology , Cell Movement/physiology , Humans , Software , Ubiquitination , Image Processing, Computer-Assisted/methods
8.
Invest Ophthalmol Vis Sci ; 65(6): 29, 2024 Jun 03.
Article in English | MEDLINE | ID: mdl-38888282

ABSTRACT

Purpose: Ubiquitination serves as a fundamental post-translational modification in numerous cellular events. Yet, its role in regulating corneal epithelial wound healing (CEWH) remains elusive. This study endeavored to determine the function and mechanism of ubiquitination in CEWH. Methods: Western blot and immunoprecipitation were used to discern ubiquitination alterations during CEWH in mice. Interventions, including neuronally expressed developmentally downregulated 4 (Nedd4) siRNA and proteasome/lysosome inhibitor, assessed their impact on CEWH. In vitro analyses, such as the scratch wound assay, MTS assay, and EdU staining, were conducted to gauge cell migration and proliferation in human corneal epithelial cells (HCECs). Moreover, transfection of miR-30/200 coupled with a luciferase activity assay ascertained their regulatory mechanism on Nedd4. Results: Global ubiquitination levels were markedly increased during the mouse CEWH. Importantly, the application of either proteasomal or lysosomal inhibitors notably impeded the healing process both in vivo and in vitro. Furthermore, Nedd4 was identified as an essential E3 ligase for CEWH. Nedd4 expression was significantly upregulated during CEWH. In vivo studies revealed that downregulation of Nedd4 substantially delayed CEWH, whereas further investigations underscored its role in regulating cell proliferation and migration, through the Stat3 pathway by targeting phosphatase and tensin homolog (PTEN). Notably, our findings pinpointed miR-30/200 family members as direct regulators of Nedd4. Conclusions: Ubiquitination holds pivotal significance in orchestrating CEWH. The critical E3 ligase Nedd4, under the regulatory purview of miR-30 and miR-200, facilitates CEWH through PTEN-mediated Stat3 signaling. This revelation sheds light on a prospective therapeutic target within the realm of CEWH.


Subject(s)
Cell Movement , Cell Proliferation , Epithelium, Corneal , Nedd4 Ubiquitin Protein Ligases , PTEN Phosphohydrolase , Ubiquitin-Protein Ligases , Ubiquitination , Wound Healing , Nedd4 Ubiquitin Protein Ligases/metabolism , Nedd4 Ubiquitin Protein Ligases/genetics , Animals , Mice , Cell Movement/physiology , Cell Proliferation/physiology , Wound Healing/physiology , PTEN Phosphohydrolase/metabolism , PTEN Phosphohydrolase/genetics , Epithelium, Corneal/metabolism , Ubiquitin-Protein Ligases/metabolism , Ubiquitin-Protein Ligases/genetics , Humans , Mice, Inbred C57BL , Endosomal Sorting Complexes Required for Transport/metabolism , Blotting, Western , STAT3 Transcription Factor/metabolism , Cells, Cultured , Disease Models, Animal , MicroRNAs/genetics , Immunoprecipitation , Male , Gene Expression Regulation/physiology
9.
J Vis Exp ; (207)2024 May 31.
Article in English | MEDLINE | ID: mdl-38884490

ABSTRACT

Angiogenesis plays a crucial role in both physiological and pathological processes within the body including tumor growth or neovascular eye disease. A detailed understanding of the underlying molecular mechanisms and reliable screening models are essential for targeting diseases effectively and developing new therapeutic options. Several in vitro assays have been developed to model angiogenesis, capitalizing on the opportunities a controlled environment provides to elucidate angiogenic drivers at a molecular level and screen for therapeutic targets. This study presents workflows for investigating angiogenesis in vitro using human umbilical vein endothelial cells (HUVECs). We detail a scratch wound migration assay utilizing a live cell imaging system measuring endothelial cell migration in a 2D setting and the spheroid sprouting assay assessing endothelial cell sprouting in a 3D setting provided by a collagen matrix. Additionally, we outline strategies for sample preparation to enable further molecular analyses such as transcriptomics, particularly in the 3D setting, including RNA extraction as well as immunocytochemistry. Altogether, this framework offers scientists a reliable and versatile toolset to pursue their scientific inquiries in in vitro angiogenesis assays.


Subject(s)
Cell Movement , Human Umbilical Vein Endothelial Cells , Neovascularization, Physiologic , Humans , Neovascularization, Physiologic/physiology , Cell Movement/physiology , Spheroids, Cellular/cytology , Angiogenesis
10.
J Vis Exp ; (207)2024 May 24.
Article in English | MEDLINE | ID: mdl-38856221

ABSTRACT

The adaptive immune response is reliant on a T cell's ability to migrate through blood, lymph, and tissue in response to pathogens and foreign bodies. T cell migration is a complex process that requires the coordination of many signal inputs from the environment and local immune cells, including chemokines, chemokine receptors, and adhesion molecules. Furthermore, T cell motility is influenced by dynamic surrounding environmental cues, which can alter activation state, transcriptional landscape, adhesion molecule expression, and more. In vivo, the complexity of these seemingly intertwined factors makes it difficult to distinguish individual signals that contribute to T cell migration. This protocol provides a string of methods from T cell isolation to computer-aided analysis to assess T cell migration in real-time under highly specific environmental conditions. These conditions may help elucidate mechanisms that regulate migration, improving our understanding of T cell kinetics and providing strong mechanistic evidence that is difficult to attain through animal experiments. A deeper understanding of the molecular interactions that impact cell migration is important to develop improved therapeutics.


Subject(s)
CD8-Positive T-Lymphocytes , Cell Movement , Animals , Mice , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/cytology , Cell Movement/physiology , Cell Movement/immunology , Cell Migration Assays/methods
11.
Phys Rev Lett ; 132(21): 218402, 2024 May 24.
Article in English | MEDLINE | ID: mdl-38856284

ABSTRACT

Biological tissues transform between solid- and liquidlike states in many fundamental physiological events. Recent experimental observations further suggest that in two-dimensional epithelial tissues these solid-liquid transformations can happen via intermediate states akin to the intermediate hexatic phases observed in equilibrium two-dimensional melting. The hexatic phase is characterized by quasi-long-range (power-law) orientational order but no translational order, thus endowing some structure to an otherwise structureless fluid. While it has been shown that hexatic order in tissue models can be induced by motility and thermal fluctuations, the role of cell division and apoptosis (birth and death) has remained poorly understood, despite its fundamental biological role. Here we study the effect of cell division and apoptosis on global hexatic order within the framework of the self-propelled Voronoi model of tissue. Although cell division naively destroys order and active motility facilitates deformations, we show that their combined action drives a liquid-hexatic-liquid transformation as the motility increases. The hexatic phase is accessed by the delicate balance of dislocation defect generation from cell division and the active binding of disclination-antidisclination pairs from motility. We formulate a mean-field model to elucidate this competition between cell division and motility and the consequent development of hexatic order.


Subject(s)
Cell Division , Cell Movement , Models, Biological , Cell Movement/physiology , Cell Division/physiology , Apoptosis/physiology
12.
J Cardiothorac Surg ; 19(1): 314, 2024 Jun 01.
Article in English | MEDLINE | ID: mdl-38824534

ABSTRACT

BACKGROUND: Asthma is a respiratory disease characterized by airway remodeling. We aimed to find out the role and mechanism of lncRNA MEG3 in asthma. METHODS: We established a cellular model of asthma by inducing human airway smooth muscle cells (HASMCs) with PDGF-BB, and detected levels of lncRNA MEG3, miR-143-3p and FGF9 in HASMCs through qRT-PCR. The functions of lncRNA MEG3 or miR-143-3p on HASMCs were explored by cell transfection. The binding sites of miR-143-3p and FGF9 were subsequently analyzed with bioinformatics software, and validated with dual-luciferase reporter assay. MTT, 5-Ethynyl-2'-deoxyuridine (EdU) assay, and Transwell were used to detect the effects of lncRNA MEG3 or miR-143-3p on proliferation and migration of HASMCs. QRT-PCR and western blot assay were used to evaluate the level of proliferation-related marker PCNA in HASMCs. RESULTS: The study found that lncRNA MEG3 negatively correlated with miR-143-3p, and miR-143-3p could directly target with FGF9. Silence of lncRNA MEG3 can suppress migration and proliferation of PDGF-BB-induced HASMCs via increasing miR-143-3p. Further mechanistic studies revealed that miR-143-3p negatively regulated FGF9 expression in HASMCs. MiR-143-3p could inhibit PDGF-BB-induced HASMCs migration and proliferation through downregulating FGF9. CONCLUSION: LncRNA MEG3 silencing could inhibit the migration and proliferation of HASMCs through regulating miR-143-3p/FGF9 signaling axis. These results imply that lncRNA MEG3 plays a protective role against asthma.


Subject(s)
Asthma , Cell Movement , Cell Proliferation , Fibroblast Growth Factor 9 , MicroRNAs , Myocytes, Smooth Muscle , RNA, Long Noncoding , RNA, Long Noncoding/genetics , RNA, Long Noncoding/metabolism , Humans , MicroRNAs/genetics , MicroRNAs/metabolism , Cell Movement/physiology , Cell Proliferation/physiology , Cell Proliferation/genetics , Asthma/genetics , Asthma/metabolism , Myocytes, Smooth Muscle/metabolism , Fibroblast Growth Factor 9/genetics , Fibroblast Growth Factor 9/metabolism , Cells, Cultured , Airway Remodeling/physiology , Airway Remodeling/genetics
13.
PLoS Comput Biol ; 20(6): e1012112, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38861575

ABSTRACT

Cell sedimentation in 3D hydrogel cultures refers to the vertical migration of cells towards the bottom of the space. Understanding this poorly examined phenomenon may allow us to design better protocols to prevent it, as well as provide insights into the mechanobiology of cancer development. We conducted a multiscale experimental and mathematical examination of 3D cancer growth in triple negative breast cancer cells. Migration was examined in the presence and absence of Paclitaxel, in high and low adhesion environments and in the presence of fibroblasts. The observed behaviour was modeled by hypothesizing active migration due to self-generated chemotactic gradients. Our results did not reject this hypothesis, whereby migration was likely to be regulated by the MAPK and TGF-ß pathways. The mathematical model enabled us to describe the experimental data in absence (normalized error<40%) and presence of Paclitaxel (normalized error<10%), suggesting inhibition of random motion and advection in the latter case. Inhibition of sedimentation in low adhesion and co-culture experiments further supported the conclusion that cells actively migrated downwards due to the presence of signals produced by cells already attached to the adhesive glass surface.


Subject(s)
Cell Adhesion , Cell Movement , Paclitaxel , Humans , Cell Adhesion/physiology , Cell Movement/physiology , Paclitaxel/pharmacology , Cell Line, Tumor , Models, Biological , Cell Culture Techniques, Three Dimensional/methods , Triple Negative Breast Neoplasms/pathology , Computational Biology , Fibroblasts/physiology , Chemotaxis/physiology
14.
J Dent Res ; 103(7): 723-733, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38822570

ABSTRACT

A ligature-induced periodontitis model was established in wild-type and CD146CreERT2; RosatdTomato mice to explore the function of pericytes in alveolar bone formation. We found that during periodontitis progression and periodontal wound healing, CD146+/NG2+ pericytes were enriched in the periodontal tissue areas, which could migrate to the alveolar bone surface and colocalize with ALP+/OCN+ osteoblasts. Chemokine C-X-C motif receptor 4 (CXCR4) inhibition using AMD3100 blocked CD146-Cre+ pericyte migration and osteogenesis, as well as further exacerbated periodontitis-associated bone loss. Next, primary pericytes were sorted out by magnetic-activated cell sorting and demonstrated that C-X-C motif chemokine ligand 12 (CXCL12) promotes pericyte migration and osteogenesis via CXCL12-CXCR4-Rac1 signaling. Finally, the local administration of an adeno-associated virus for Rac1 overexpression in NG2+ pericytes promotes osteoblast differentiation of pericytes and increases alveolar bone volume in periodontitis. Thus, our results provided the evidence that pericytes may migrate and osteogenesis via the CXCL12-CXCR4-Rac1 axis during the pathological process of periodontitis.


Subject(s)
Cell Movement , Chemokine CXCL12 , Osteogenesis , Pericytes , Periodontitis , Receptors, CXCR4 , Animals , Osteogenesis/physiology , Cell Movement/physiology , Mice , Chemokine CXCL12/metabolism , Receptors, CXCR4/metabolism , Alveolar Bone Loss , Signal Transduction/physiology , rac1 GTP-Binding Protein/metabolism , Disease Models, Animal , CD146 Antigen , Osteoblasts , Cell Differentiation , Cyclams , Benzylamines
15.
Proc Natl Acad Sci U S A ; 121(26): e2400804121, 2024 Jun 25.
Article in English | MEDLINE | ID: mdl-38900800

ABSTRACT

Chirality plays a crucial role in biology, as it is highly conserved and fundamentally important in the developmental process. To better understand the relationship between the chirality of individual cells and that of tissues and organisms, we develop a generalized mechanics model of chiral polarized particles to investigate the swirling dynamics of cell populations on substrates. Our analysis reveals that cells with the same chirality can form distinct chiral patterns on ring-shaped or rectangular substrates. Interestingly, our studies indicate that an excessively strong or weak individual cellular chirality hinders the formation of such chiral patterns. Our studies also indicate that there exists the influence distance of substrate boundaries in chiral patterns. Smaller influence distances are observed when cell-cell interactions are weaker. Conversely, when cell-cell interactions are too strong, multiple cells tend to be stacked together, preventing the formation of chiral patterns on substrates in our analysis. Additionally, we demonstrate that the interaction between cells and substrate boundaries effectively controls the chiral distribution of cellular orientations on ring-shaped substrates. This research highlights the significance of coordinating boundary features, individual cellular chirality, and cell-cell interactions in governing the chiral movement of cell populations and provides valuable mechanics insights into comprehending the intricate connection between the chirality of single cells and that of tissues and organisms.


Subject(s)
Cell Communication , Models, Biological , Cell Communication/physiology , Cell Movement/physiology , Cell Polarity/physiology
16.
J Cell Sci ; 137(12)2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38832512

ABSTRACT

As cells migrate through biological tissues, they must frequently squeeze through micron-sized constrictions in the form of interstitial pores between extracellular matrix fibers and/or other cells. Although it is now well recognized that such confined migration is limited by the nucleus, which is the largest and stiffest organelle, it remains incompletely understood how cells apply sufficient force to move their nucleus through small constrictions. Here, we report a mechanism by which contraction of the cell rear cortex pushes the nucleus forward to mediate nuclear transit through constrictions. Laser ablation of the rear cortex reveals that pushing forces behind the nucleus are the result of increased intracellular pressure in the rear compartment of the cell. The pushing forces behind the nucleus depend on accumulation of actomyosin in the rear cortex and require Rho kinase (ROCK) activity. Collectively, our results suggest a mechanism by which cells generate elevated intracellular pressure in the posterior compartment to facilitate nuclear transit through three-dimensional (3D) constrictions. This mechanism might supplement or even substitute for other mechanisms supporting nuclear transit, ensuring robust cell migrations in confined 3D environments.


Subject(s)
Cell Movement , Cell Nucleus , Cell Nucleus/metabolism , Cell Movement/physiology , Humans , Actomyosin/metabolism , rho-Associated Kinases/metabolism , Animals , Pressure , Mice
17.
Math Biosci ; 374: 109240, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38906525

ABSTRACT

A fundamental feature of collective cell migration is phenotypic heterogeneity which, for example, influences tumour progression and relapse. While current mathematical models often consider discrete phenotypic structuring of the cell population, in-line with the 'go-or-grow' hypothesis (Hatzikirou et al., 2012; Stepien et al., 2018), they regularly overlook the role that the environment may play in determining the cells' phenotype during migration. Comparing a previously studied volume-filling model for a homogeneous population of generalist cells that can proliferate, move and degrade extracellular matrix (ECM) (Crossley et al., 2023) to a novel model for a heterogeneous population comprising two distinct sub-populations of specialist cells that can either move and degrade ECM or proliferate, this study explores how different hypothetical phenotypic switching mechanisms affect the speed and structure of the invading cell populations. Through a continuum model derived from its individual-based counterpart, insights into the influence of the ECM and the impact of phenotypic switching on migrating cell populations emerge. Notably, specialist cell populations that cannot switch phenotype show reduced invasiveness compared to generalist cell populations, while implementing different forms of switching significantly alters the structure of migrating cell fronts. This key result suggests that the structure of an invading cell population could be used to infer the underlying mechanisms governing phenotypic switching.


Subject(s)
Cell Movement , Extracellular Matrix , Models, Biological , Phenotype , Extracellular Matrix/physiology , Cell Movement/physiology , Humans , Cell Proliferation/physiology
18.
J Theor Biol ; 592: 111882, 2024 Sep 07.
Article in English | MEDLINE | ID: mdl-38944379

ABSTRACT

Regulation of cell proliferation is a crucial aspect of tissue development and homeostasis and plays a major role in morphogenesis, wound healing, and tumor invasion. A phenomenon of such regulation is contact inhibition, which describes the dramatic slowing of proliferation, cell migration and individual cell growth when multiple cells are in contact with each other. While many physiological, molecular and genetic factors are known, the mechanism of contact inhibition is still not fully understood. In particular, the relevance of cellular signaling due to interfacial contact for contact inhibition is still debated. Cellular automata (CA) have been employed in the past as numerically efficient mathematical models to study the dynamics of cell ensembles, but they are not suitable to explore the origins of contact inhibition as such agent-based models assume fixed cell sizes. We develop a minimal, data-driven model to simulate the dynamics of planar cell cultures by extending a probabilistic CA to incorporate size changes of individual cells during growth and cell division. We successfully apply this model to previous in-vitro experiments on contact inhibition in epithelial tissue: After a systematic calibration of the model parameters to measurements of single-cell dynamics, our CA model quantitatively reproduces independent measurements of emergent, culture-wide features, like colony size, cell density and collective cell migration. In particular, the dynamics of the CA model also exhibit the transition from a low-density confluent regime to a stationary postconfluent regime with a rapid decrease in cell size and motion. This implies that the volume exclusion principle, a mechanical constraint which is the only inter-cellular interaction incorporated in the model, paired with a size-dependent proliferation rate is sufficient to generate the observed contact inhibition. We discuss how our approach enables the introduction of effective bio-mechanical interactions in a CA framework for future studies.


Subject(s)
Cell Proliferation , Cell Size , Epithelial Cells , Models, Biological , Cell Proliferation/physiology , Epithelial Cells/cytology , Epithelial Cells/physiology , Contact Inhibition/physiology , Humans , Animals , Cell Movement/physiology
19.
Bull Math Biol ; 86(8): 95, 2024 Jun 19.
Article in English | MEDLINE | ID: mdl-38896328

ABSTRACT

Epithelial monolayers are some of the best-studied models for collective cell migration due to their abundance in multicellular systems and their tractability. Experimentally, the collective migration of epithelial monolayers can be robustly steered e.g. using electric fields, via a process termed electrotaxis. Theoretically, however, the question of how to design an electric field to achieve a desired spatiotemporal movement pattern is underexplored. In this work, we construct and calibrate an ordinary differential equation model to predict the average velocity of the centre of mass of a cellular monolayer in response to stimulation with an electric field. We use this model, in conjunction with optimal control theory, to derive physically realistic optimal electric field designs to achieve a variety of aims, including maximising the total distance travelled by the monolayer, maximising the monolayer velocity, and keeping the monolayer velocity constant during stimulation. Together, this work is the first to present a unified framework for optimal control of collective monolayer electrotaxis and provides a blueprint to optimally steer collective migration using other external cues.


Subject(s)
Cell Movement , Epithelial Cells , Mathematical Concepts , Models, Biological , Epithelial Cells/physiology , Epithelial Cells/cytology , Cell Movement/physiology , Animals , Computer Simulation , Taxis Response/physiology , Dogs , Humans , Madin Darby Canine Kidney Cells
20.
J Vis Exp ; (207)2024 May 17.
Article in English | MEDLINE | ID: mdl-38829132

ABSTRACT

Microglia are highly dynamic cells and their migration and colonization of the brain parenchyma is a crucial step for proper brain development and function. Externally developing zebrafish embryos possess optical transparency, which along with well-characterized transgenic reporter lines that fluorescently label microglia, make zebrafish an ideal vertebrate model for such studies. In this paper, we take advantage of the unique features of the zebrafish model to visualize the dynamics of microglia cells in vivo and under physiological conditions. We use confocal microscopy to record a timelapse of microglia cells in the optic tectum of the zebrafish embryo and then, extract tracking data using the IMARIS 10.0 software to obtain the cells' migration path, mean speed, and distribution in the optic tectum at different developmental stages. This protocol can be a useful tool to elucidate the physiological significance of microglia behavior in various contexts, contributing to a deeper characterization of these highly motile cells.


Subject(s)
Microglia , Microscopy, Confocal , Zebrafish , Animals , Zebrafish/embryology , Microglia/cytology , Microscopy, Confocal/methods , Cell Movement/physiology , Superior Colliculi/cytology , Superior Colliculi/physiology , Embryo, Nonmammalian/cytology
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