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1.
PLoS One ; 19(8): e0285638, 2024.
Article in English | MEDLINE | ID: mdl-39106254

ABSTRACT

Acute respiratory distress syndrome (ARDS) has a fibroproliferative phase that may be followed by pulmonary fibrosis. Pulmonary fibrosis following COVID-19 pneumonia has been described at autopsy and following lung transplantation. We hypothesized that protein mediators of tissue remodeling and monocyte chemotaxis are elevated in the plasma and endotracheal aspirates of critically ill patients with COVID-19 who subsequently develop features of pulmonary fibroproliferation. We enrolled COVID-19 patients admitted to the ICU with hypoxemic respiratory failure. (n = 195). Plasma was collected within 24h of ICU admission and at 7d. In mechanically ventilated patients, endotracheal aspirates (ETA) were collected. Protein concentrations were measured by immunoassay. We tested for associations between protein concentrations and respiratory outcomes using logistic regression adjusting for age, sex, treatment with steroids, and APACHE III score. In a subset of patients who had CT scans during hospitalization (n = 75), we tested for associations between protein concentrations and radiographic features of fibroproliferation. Among the entire cohort, plasma IL-6, TNF-α, CCL2, and Amphiregulin levels were significantly associated with in-hospital mortality. In addition, higher plasma concentrations of CCL2, IL-6, TNF-α, Amphiregulin, and CXCL12 were associated with fewer ventilator-free days. We identified 20/75 patients (26%) with features of fibroproliferation. Within 24h of ICU admission, no measured plasma proteins were associated with a fibroproliferative response. However, when measured 96h-128h after admission, Amphiregulin was elevated in those that developed fibroproliferation. ETAs were not correlated with plasma measurements and did not show any association with mortality, ventilator-free days (VFDs), or fibroproliferative response. This cohort study identifies proteins of tissue remodeling and monocyte recruitment are associated with in-hospital mortality, fewer VFDs, and radiographic fibroproliferative response. Measuring changes in these proteins over time may allow for early identification of patients with severe COVID-19 at risk for fibroproliferation.


Subject(s)
COVID-19 , Pulmonary Fibrosis , Humans , COVID-19/mortality , COVID-19/blood , COVID-19/pathology , Male , Female , Middle Aged , Aged , Pulmonary Fibrosis/pathology , Pulmonary Fibrosis/blood , Pulmonary Fibrosis/mortality , Monocytes/metabolism , Hospital Mortality , SARS-CoV-2 , Lung/pathology , Chemotaxis, Leukocyte , Chemotaxis
2.
Biomolecules ; 14(7)2024 Jul 10.
Article in English | MEDLINE | ID: mdl-39062545

ABSTRACT

Cell-to-cell communication is fundamental to the organization and functionality of multicellular organisms. Intercellular signals orchestrate a variety of cellular responses, including gene expression and protein function changes, and contribute to the integrated functions of individual tissues. Dictyostelium discoideum is a model organism for cell-to-cell interactions mediated by chemical signals and multicellular formation mechanisms. Upon starvation, D. discoideum cells exhibit coordinated cell aggregation via cyclic adenosine 3',5'-monophosphate (cAMP) gradients and chemotaxis, which facilitates the unicellular-to-multicellular transition. During this process, the calcium signaling synchronizes with the cAMP signaling. The resulting multicellular body exhibits organized collective migration and ultimately forms a fruiting body. Various signaling molecules, such as ion signals, regulate the spatiotemporal differentiation patterns within multicellular bodies. Understanding cell-to-cell and ion signaling in Dictyostelium provides insight into general multicellular formation and differentiation processes. Exploring cell-to-cell and ion signaling enhances our understanding of the fundamental biological processes related to cell communication, coordination, and differentiation, with wide-ranging implications for developmental biology, evolutionary biology, biomedical research, and synthetic biology. In this review, I discuss the role of ion signaling in cell motility and development in D. discoideum.


Subject(s)
Cell Movement , Cyclic AMP , Dictyostelium , Signal Transduction , Dictyostelium/metabolism , Dictyostelium/growth & development , Dictyostelium/genetics , Dictyostelium/cytology , Cyclic AMP/metabolism , Chemotaxis , Cell Communication , Ions/metabolism , Cell Differentiation , Calcium Signaling
3.
Elife ; 132024 Jul 01.
Article in English | MEDLINE | ID: mdl-38949655

ABSTRACT

Secreted chemokines form concentration gradients in target tissues to control migratory directions and patterns of immune cells in response to inflammatory stimulation; however, how the gradients are formed is much debated. Heparan sulfate (HS) binds to chemokines and modulates their activities. In this study, we investigated the roles of HS in the gradient formation and chemoattractant activity of CCL5 that is known to bind to HS. CCL5 and heparin underwent liquid-liquid phase separation and formed gradient, which was confirmed using CCL5 immobilized on heparin-beads. The biological implication of HS in CCL5 gradient formation was established in CHO-K1 (wild-type) and CHO-677 (lacking HS) cells by Transwell assay. The effect of HS on CCL5 chemoattractant activity was further proved by Transwell assay of human peripheral blood cells. Finally, peritoneal injection of the chemokines into mice showed reduced recruitment of inflammatory cells either by mutant CCL5 (lacking heparin-binding sequence) or by addition of heparin to wild-type CCL5. Our experimental data propose that co-phase separation of CCL5 with HS establishes a specific chemokine concentration gradient to trigger directional cell migration. The results warrant further investigation on other heparin-binding chemokines and allows for a more elaborate insight into disease process and new treatment strategies.


Subject(s)
Chemokine CCL5 , Chemotaxis , Cricetulus , Heparitin Sulfate , Chemokine CCL5/metabolism , Chemokine CCL5/genetics , Animals , Heparitin Sulfate/metabolism , Humans , CHO Cells , Mice , Heparin/metabolism , Heparin/pharmacology , Phase Separation
4.
J Neuroinflammation ; 21(1): 167, 2024 Jul 02.
Article in English | MEDLINE | ID: mdl-38956605

ABSTRACT

BACKGROUND: Deposition of amyloid ß, which is produced by amyloidogenic cleavage of APP by ß- and γ-secretase, is one of the primary hallmarks of AD pathology. APP can also be processed by α- and γ-secretase sequentially, to generate sAPPα, which has been shown to be neuroprotective by promoting neurite outgrowth and neuronal survival, etc. METHODS: The global expression profiles of miRNA in blood plasma samples taken from 11 AD patients as well as from 14 age and sex matched cognitively normal volunteers were analyzed using miRNA-seq. Then, overexpressed miR-140 and miR-122 both in vivo and in vitro, and knock-down of the endogenous expression of miR-140 and miR-122 in vitro. Used a combination of techniques, including molecular biology, immunohistochemistry, to detect the impact of miRNAs on AD pathology. RESULTS: In this study, we identified that two miRNAs, miR-140-3p and miR-122-5p, both targeting ADAM10, the main α-secretase in CNS, were upregulated in the blood plasma of AD patients. Overexpression of these two miRNAs in mouse brains induced cognitive decline in wild type C57BL/6J mice as well as exacerbated dyscognition in APP/PS1 mice. Although significant changes in APP and total Aß were not detected, significantly downregulated ADAM10 and its non-amyloidogenic product, sAPPα, were observed in the mouse brains overexpressing miR-140/miR-122. Immunohistology analysis revealed increased neurite dystrophy that correlated with the reduced microglial chemotaxis in the hippocampi of these mice, independent of the other two ADAM10 substrates (neuronal CX3CL1 and microglial TREM2) that were involved in regulating the microglial immunoactivity. Further in vitro analysis demonstrated that both the reduced neuritic outgrowth of mouse embryonic neuronal cells overexpressing miR-140/miR-122 and the reduced Aß phagocytosis in microglia cells co-cultured with HT22 cells overexpressing miR-140/miR-122 could be rescued by overexpressing the specific inhibitory sequence of miR-140/miR-122 TuD as well as by addition of sAPPα, rendering these miRNAs as potential therapeutic targets. CONCLUSIONS: Our results suggested that neuroprotective sAPPα was a key player in the neuropathological progression induced by dysregulated expression of miR-140 and miR-122. Targeting these miRNAs might serve as a promising therapeutic strategy in AD treatment.


Subject(s)
Alzheimer Disease , Chemotaxis , Mice, Inbred C57BL , MicroRNAs , Microglia , MicroRNAs/metabolism , MicroRNAs/genetics , Animals , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Alzheimer Disease/genetics , Mice , Humans , Microglia/metabolism , Microglia/pathology , Male , Chemotaxis/physiology , Female , ADAM10 Protein/metabolism , ADAM10 Protein/genetics , Amyloid Precursor Protein Secretases/metabolism , Amyloid Precursor Protein Secretases/genetics , Mice, Transgenic , Aged , Gene Expression Regulation
5.
J Exp Clin Cancer Res ; 43(1): 202, 2024 Jul 22.
Article in English | MEDLINE | ID: mdl-39034411

ABSTRACT

BACKGROUND: Lung cancer remains one of the most prevalent cancer types worldwide, with a high mortality rate. Upregulation of programmed cell death protein 1 (PD-1) and its ligand (PD-L1) may represent a key mechanism for evading immune surveillance. Immune checkpoint blockade (ICB) antibodies against PD-1 or PD-L1 are therefore widely used to treat patients with lung cancer. However, the mechanisms by which lung cancer and neutrophils in the microenvironment sustain PD-L1 expression and impart stronger inhibition of CD8+ T cell function remain unclear. METHODS: We investigated the role and underlying mechanism by which PD-L1+ lung cancer and PD-L1+ neutrophils impede the function of CD8+ T cells through magnetic bead cell sorting, quantitative real-time polymerase chain reaction (RT-PCR), western blotting, enzyme-linked immunosorbent assays, confocal immunofluorescence, gene silencing, flow cytometry, etc. In vivo efficacy and safety studies were conducted using (Non-obeseDiabetes/severe combined immune deficiency) SCID/NOD mice. Additionally, we collected clinical and prognostic data from 208 patients who underwent curative lung cancer resection between 2017 and 2018. RESULTS: We demonstrated that C-X-C motif chemokine ligand 5 (CXCL5) is markedly overexpressed in lung cancer cells and is positively correlated with a poor prognosis in patients with lung cancer. Mechanistically, CXCL5 activates the phosphorylation of the Paxillin/AKT signaling cascade, leading to upregulation of PD-L1 expression and the formation of a positive feedback loop. Moreover, CXCL5 attracts neutrophils, compromising CD8+ T cell-dependent antitumor immunity. These PD-L1+ neutrophils aggravate CD8+ T cell exhaustion following lung cancer domestication. Combined treatment with anti-CXCL5 and anti-PD-L1 antibodies significantly inhibits tumor growth in vivo. CONCLUSIONS: Our findings collectively demonstrate that CXCL5 promotes immune escape through PD-L1 upregulation in lung cancer and neutrophils chemotaxis through autocrine and paracrine mechanisms. CXCL5 may serve as a potential therapeutic target in synergy with ICBs in lung cancer immunotherapy.


Subject(s)
B7-H1 Antigen , CD8-Positive T-Lymphocytes , Chemokine CXCL5 , Lung Neoplasms , Neutrophils , Proto-Oncogene Proteins c-akt , Humans , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/metabolism , Lung Neoplasms/immunology , Lung Neoplasms/metabolism , Lung Neoplasms/pathology , Mice , Animals , Neutrophils/metabolism , Neutrophils/immunology , Chemokine CXCL5/metabolism , Chemokine CXCL5/genetics , B7-H1 Antigen/metabolism , B7-H1 Antigen/genetics , Proto-Oncogene Proteins c-akt/metabolism , Phosphorylation , Signal Transduction , Up-Regulation , Female , Male , Chemotaxis , Mice, Inbred NOD , Mice, SCID
6.
Cell Syst ; 15(7): 628-638.e8, 2024 Jul 17.
Article in English | MEDLINE | ID: mdl-38981486

ABSTRACT

In uncertain environments, phenotypic diversity can be advantageous for survival. However, as the environmental uncertainty decreases, the relative advantage of having diverse phenotypes decreases. Here, we show how populations of E. coli integrate multiple chemical signals to adjust sensory diversity in response to changes in the prevalence of each ligand in the environment. Measuring kinase activity in single cells, we quantified the sensitivity distribution to various chemoattractants in different mixtures of background stimuli. We found that when ligands bind uncompetitively, the population tunes sensory diversity to each signal independently, decreasing diversity when the signal's ambient concentration increases. However, among competitive ligands, the population can only decrease sensory diversity one ligand at a time. Mathematical modeling suggests that sensory diversity tuning benefits E. coli populations by modulating how many cells are committed to tracking each signal proportionally as their prevalence changes.


Subject(s)
Chemotaxis , Escherichia coli , Signal Transduction , Escherichia coli/metabolism , Escherichia coli/physiology , Chemotaxis/physiology , Escherichia coli Proteins/metabolism , Escherichia coli Proteins/genetics , Chemotactic Factors/metabolism
7.
J R Soc Interface ; 21(216): 20240100, 2024 Jul.
Article in English | MEDLINE | ID: mdl-39081250

ABSTRACT

Biological systems such as axonal growth cones perform chemotaxis at micrometre-level length scales, where chemotactic molecules are sparse. Such systems lie outside the range of validity of existing models, which assume smoothly varying chemical gradients. We investigate the effect of introducing discrete chemoattractant molecules by constructing a minimal dynamical model consisting of a chemotactic cell without internal memory. Significant differences are found in the behaviour of the cell as the chemical gradient is changed from smoothly varying to discrete, including the emergence of a homing radius beyond which chemotaxis is not reliably performed.


Subject(s)
Chemotaxis , Models, Biological , Chemotaxis/physiology , Animals , Chemotactic Factors/metabolism
8.
Physiol Rep ; 12(14): e16139, 2024 Jul.
Article in English | MEDLINE | ID: mdl-39016176

ABSTRACT

The monocyte-macrophage system plays an important role in phagocytosis of pathogens and cellular debris following infection or tissue injury in several pathophysiological conditions. We examined ENaC/ASIC subunit transcript expression and the importance of select subunits in migration of bone marrow derived monocytes (freshly isolated) and macrophages (monocytes differentiated in culture). We also examined the effect of select subunit deletion on macrophage phenotype. BM monocytes were harvested from the femurs of male and female WT and KO mice (6-12 weeks of age). Our results show that α, ß, γENaC, and ASIC1-5 transcripts are expressed in BM macrophages and monocytes to varying degrees. At least αENaC, ßENaC, and ASIC2 subunits contribute to chemotactic migration responses in BM monocyte-macrophages. Polarization markers (CD86, soluble TNFα) in BM macrophages from mice lacking ASIC2a plus ßENaC were shifted towards the M1 phenotype. Furthermore, select M1 phenotypic markers were recovered with rescue of ßENaC or ASIC2. Taken together, these data suggest that ßENaC and ASIC2 play an important role in BM macrophage migration and loss of ßENaC and/or ASIC2 partially polarizes macrophages to the M1 phenotype. Thus, targeting ENaC/ASIC expression in BM macrophages may regulate their ability to migrate to sites of injury.


Subject(s)
Acid Sensing Ion Channels , Chemotaxis , Epithelial Sodium Channels , Macrophages , Monocytes , Animals , Epithelial Sodium Channels/metabolism , Epithelial Sodium Channels/genetics , Macrophages/metabolism , Male , Mice , Acid Sensing Ion Channels/metabolism , Acid Sensing Ion Channels/genetics , Female , Monocytes/metabolism , Mice, Inbred C57BL , Mice, Knockout , Bone Marrow Cells/metabolism , Cells, Cultured
9.
Nat Cell Biol ; 26(7): 1062-1076, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38951708

ABSTRACT

Ras has been extensively studied as a promoter of cell proliferation, whereas few studies have explored its role in migration. To investigate the direct and immediate effects of Ras activity on cell motility or polarity, we focused on RasGAPs, C2GAPB in Dictyostelium amoebae and RASAL3 in HL-60 neutrophils and macrophages. In both cellular systems, optically recruiting the respective RasGAP to the cell front extinguished pre-existing protrusions and changed migration direction. However, when these respective RasGAPs were recruited uniformly to the membrane, cells polarized and moved more rapidly, whereas targeting to the back exaggerated these effects. These unexpected outcomes of attenuating Ras activity naturally had strong, context-dependent consequences for chemotaxis. The RasGAP-mediated polarization depended critically on myosin II activity and commenced with contraction at the cell rear, followed by sustained mTORC2-dependent actin polymerization at the front. These experimental results were captured by computational simulations in which Ras levels control front- and back-promoting feedback loops. The discovery that inhibiting Ras activity can produce counterintuitive effects on cell migration has important implications for future drug-design strategies targeting oncogenic Ras.


Subject(s)
Actomyosin , Cell Movement , Cell Polarity , Dictyostelium , ras Proteins , Dictyostelium/metabolism , Dictyostelium/genetics , HL-60 Cells , Actomyosin/metabolism , Humans , ras Proteins/metabolism , ras Proteins/genetics , Macrophages/metabolism , Myosin Type II/metabolism , Myosin Type II/genetics , Neutrophils/metabolism , ras GTPase-Activating Proteins/metabolism , ras GTPase-Activating Proteins/genetics , Animals , Chemotaxis , Protozoan Proteins/metabolism , Protozoan Proteins/genetics , Actins/metabolism , Computer Simulation , Mice , Signal Transduction
10.
ISME J ; 18(1)2024 Jan 08.
Article in English | MEDLINE | ID: mdl-38995932

ABSTRACT

Marine planktonic predator-prey interactions occur in microscale seascapes, where diffusing chemicals may act either as chemotactic cues that enhance or arrest predation, or as elemental resources that are complementary to prey ingestion. The phytoplankton osmolyte dimethylsulfoniopropionate (DMSP) and its degradation products dimethylsulfide (DMS) and acrylate are pervasive compounds with high chemotactic potential, but there is a longstanding controversy over whether they act as grazing enhancers or deterrents. Here, we investigated the chemotactic responses of three herbivorous dinoflagellates to point-sourced, microscale gradients of dissolved DMSP, DMS, and acrylate. We found no evidence for acrylate being a chemotactic repellent and observed a weak attractor role of DMS. DMSP behaved as a strong chemoattractor whose potential for grazing facilitation through effects on swimming patterns and aggregation depends on the grazer's feeding mode and ability to incorporate DMSP. Our study reveals that predation models will fail to predict grazing impacts unless they incorporate chemotaxis-driven searching and finding of prey.


Subject(s)
Chemotaxis , Dinoflagellida , Herbivory , Sulfonium Compounds , Sulfonium Compounds/metabolism , Dinoflagellida/physiology , Acrylates , Sulfides/metabolism , Sulfides/pharmacology , Phytoplankton/physiology , Animals , Predatory Behavior , Food Chain
12.
mBio ; 15(7): e0087124, 2024 Jul 17.
Article in English | MEDLINE | ID: mdl-38899869

ABSTRACT

Chemosensory systems allow bacteria to respond and adapt to environmental conditions. Many bacteria contain more than one chemosensory system, but knowledge of their specific roles in regulating different functions remains scarce. Here, we address this issue by analyzing the function of the F6, F8, and alternative (non-motility) cellular functions (ACF) chemosensory systems of the model plant pathogen Pseudomonas syringae pv. tomato. In this work, we assign PsPto chemoreceptors to each chemosensory system, and we visualize for the first time the F6 and F8 chemosensory systems of PsPto using cryo-electron tomography. We confirm that chemotaxis and swimming motility are controlled by the F6 system, and we demonstrate how different components from the F8 and ACF systems also modulate swimming motility. We also determine how the kinase and response regulators from the F6 and F8 chemosensory systems do not work together in the regulation of biofilm, whereas both components from the ACF system contribute together to regulate these traits. Furthermore, we show how the F6, F8, and ACF kinases interact with the ACF response regulator WspR, supporting crosstalk among chemosensory systems. Finally, we reveal how all chemosensory systems play a role in regulating virulence. IMPORTANCE: Chemoperception through chemosensory systems is an essential feature for bacterial survival, as it allows bacterial interaction with its surrounding environment. In the case of plant pathogens, it is especially relevant to enter the host and achieve full virulence. Multiple chemosensory systems allow bacteria to display a wider plasticity in their response to external signals. Here, we perform a deep characterization of the F6, F8, and alternative (non-motility) cellular functions chemosensory systems in the model plant pathogen Pseudomonas syringae pv. tomato DC3000. These chemosensory systems regulate key virulence-related traits, like motility and biofilm formation. Furthermore, we unveil an unexpected crosstalk among these chemosensory systems at the level of the interaction between kinases and response regulators. This work shows novel results that contribute to the knowledge of chemosensory systems and their role in functions alternative to chemotaxis.


Subject(s)
Bacterial Proteins , Biofilms , Chemotaxis , Pseudomonas syringae , Solanum lycopersicum , Pseudomonas syringae/genetics , Pseudomonas syringae/pathogenicity , Pseudomonas syringae/metabolism , Pseudomonas syringae/physiology , Bacterial Proteins/metabolism , Bacterial Proteins/genetics , Biofilms/growth & development , Solanum lycopersicum/microbiology , Virulence , Plant Diseases/microbiology , Gene Expression Regulation, Bacterial
13.
PLoS Biol ; 22(6): e3002672, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38935621

ABSTRACT

Throughout history, humans have relied on plants as a source of medication, flavoring, and food. Plants synthesize large chemical libraries and release many of these compounds into the rhizosphere and atmosphere where they affect animal and microbe behavior. To survive, nematodes must have evolved the sensory capacity to distinguish plant-made small molecules (SMs) that are harmful and must be avoided from those that are beneficial and should be sought. This ability to classify chemical cues as a function of their value is fundamental to olfaction and represents a capacity shared by many animals, including humans. Here, we present an efficient platform based on multiwell plates, liquid handling instrumentation, inexpensive optical scanners, and bespoke software that can efficiently determine the valence (attraction or repulsion) of single SMs in the model nematode, Caenorhabditis elegans. Using this integrated hardware-wetware-software platform, we screened 90 plant SMs and identified 37 that attracted or repelled wild-type animals but had no effect on mutants defective in chemosensory transduction. Genetic dissection indicates that for at least 10 of these SMs, response valence emerges from the integration of opposing signals, arguing that olfactory valence is often determined by integrating chemosensory signals over multiple lines of information. This study establishes that C. elegans is an effective discovery engine for determining chemotaxis valence and for identifying natural products detected by the chemosensory nervous system.


Subject(s)
Caenorhabditis elegans , Chemotaxis , High-Throughput Screening Assays , Caenorhabditis elegans/physiology , Caenorhabditis elegans/drug effects , Animals , High-Throughput Screening Assays/methods , Smell/physiology , Behavior, Animal/drug effects , Behavior, Animal/physiology , Software
14.
Sci Adv ; 10(24): eadk9731, 2024 Jun 14.
Article in English | MEDLINE | ID: mdl-38865458

ABSTRACT

Nonlinear biomolecular interactions on membranes drive membrane remodeling crucial for biological processes including chemotaxis, cytokinesis, and endocytosis. The complexity of biomolecular interactions, their redundancy, and the importance of spatiotemporal context in membrane organization impede understanding of the physical principles governing membrane mechanics. Developing a minimal in vitro system that mimics molecular signaling and membrane remodeling while maintaining physiological fidelity poses a major challenge. Inspired by chemotaxis, we reconstructed chemically regulated actin polymerization inside vesicles, guiding membrane self-organization. An external, undirected chemical input induced directed actin polymerization and membrane deformation uncorrelated with upstream biochemical cues, suggesting symmetry breaking. A biophysical model incorporating actin dynamics and membrane mechanics proposes that uneven actin distributions cause nonlinear membrane deformations, consistent with experimental findings. This protocellular system illuminates the interplay between actin dynamics and membrane shape during symmetry breaking, offering insights into chemotaxis and other cell biological processes.


Subject(s)
Actins , Artificial Cells , Cell Membrane , Polymerization , Actins/metabolism , Artificial Cells/metabolism , Artificial Cells/chemistry , Cell Membrane/metabolism , Chemotaxis , Models, Biological
15.
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
16.
Cells ; 13(11)2024 May 26.
Article in English | MEDLINE | ID: mdl-38891050

ABSTRACT

Acute inflammation is a rapid and dynamic process involving the recruitment and activation of multiple cell types in a coordinated and precise manner. Here, we investigate the origin and transcriptional reprogramming of monocytes using a model of acute inflammation, zymosan-induced peritonitis. Monocyte trafficking and adoptive transfer experiments confirmed that monocytes undergo rapid phenotypic change as they exit the blood and give rise to monocyte-derived macrophages that persist during the resolution of inflammation. Single-cell transcriptomics revealed significant heterogeneity within the surface marker-defined CD11b+Ly6G-Ly6Chi monocyte populations within the blood and at the site of inflammation. We show that two major transcriptional reprogramming events occur during the initial six hours of Ly6Chi monocyte mobilisation, one in the blood priming monocytes for migration and a second at the site of inflammation. Pathway analysis revealed an important role for oxidative phosphorylation (OxPhos) during both these reprogramming events. Experimentally, we demonstrate that OxPhos via the intact mitochondrial electron transport chain is essential for murine and human monocyte chemotaxis. Moreover, OxPhos is needed for monocyte-to-macrophage differentiation and macrophage M(IL-4) polarisation. These new findings from transcriptional profiling open up the possibility that shifting monocyte metabolic capacity towards OxPhos could facilitate enhanced macrophage M2-like polarisation to aid inflammation resolution and tissue repair.


Subject(s)
Antigens, Ly , Cell Differentiation , Inflammation , Macrophages , Monocytes , Oxidative Phosphorylation , Monocytes/metabolism , Animals , Macrophages/metabolism , Inflammation/pathology , Inflammation/metabolism , Humans , Mice , Antigens, Ly/metabolism , Chemotaxis , Mice, Inbred C57BL , Peritonitis/metabolism , Peritonitis/chemically induced , Peritonitis/pathology , Zymosan/pharmacology , Mitochondria/metabolism , Cellular Reprogramming
17.
Elife ; 122024 Jun 04.
Article in English | MEDLINE | ID: mdl-38832501

ABSTRACT

Bacteria in biofilms secrete potassium ions to attract free swimming cells. However, the basis of chemotaxis to potassium remains poorly understood. Here, using a microfluidic device, we found that Escherichia coli can rapidly accumulate in regions of high potassium concentration on the order of millimoles. Using a bead assay, we measured the dynamic response of individual flagellar motors to stepwise changes in potassium concentration, finding that the response resulted from the chemotaxis signaling pathway. To characterize the chemotactic response to potassium, we measured the dose-response curve and adaptation kinetics via an Förster resonance energy transfer (FRET) assay, finding that the chemotaxis pathway exhibited a sensitive response and fast adaptation to potassium. We further found that the two major chemoreceptors Tar and Tsr respond differently to potassium. Tar receptors exhibit a biphasic response, whereas Tsr receptors respond to potassium as an attractant. These different responses were consistent with the responses of the two receptors to intracellular pH changes. The sensitive response and fast adaptation allow bacteria to sense and localize small changes in potassium concentration. The differential responses of Tar and Tsr receptors to potassium suggest that cells at different growth stages respond differently to potassium and may have different requirements for potassium.


Subject(s)
Chemotaxis , Escherichia coli , Potassium , Potassium/metabolism , Escherichia coli/physiology , Escherichia coli Proteins/metabolism , Fluorescence Resonance Energy Transfer , Signal Transduction , Receptors, Cell Surface
18.
PLoS One ; 19(6): e0305037, 2024.
Article in English | MEDLINE | ID: mdl-38837976

ABSTRACT

Bacteria use various motility mechanisms to explore their environments. Chemotaxis is the ability of a motile bacterial cell to direct its movement in response to chemical gradients. A number of methods have been developed and widely used to study chemotactic responses to chemoeffectors including capillary, agar plug, microscopic slide, and microfluidic assays. While valuable, these assays are primarily designed to monitor rapid chemotactic responses to chemoeffectors on a small scale, which poses challenges in collecting large quantities of attracted bacteria. Consequently, these setups are not ideal for experiments like forward genetic screens. To overcome this limitation, we developed the Large Scale Bacterial Attraction assay (LSBA), which relies on the use of a Nalgene™ Reusable Filter Unit and other materials commonly found in laboratories. We validate the LSBA by investigating chemoeffector kinetics in the setup and by using chemoattractants to quantify the chemotactic response of wild-type, and motility impaired strains of the plant pathogenic bacterium Xanthomonas campestris pv. campestris and the environmental bacterium Shewanella oneidensis. We show that the LSBA establishes a long lasting chemoeffector gradient, that the setup can be used to quantify bacterial migration over time and that the LSBA offers the possibility to collect high numbers of attracted bacteria, making it suitable for genetic screens.


Subject(s)
Chemotaxis , Shewanella , Chemotaxis/genetics , Shewanella/genetics , Shewanella/physiology , Xanthomonas campestris/genetics , Genetic Testing/methods , Chemotactic Factors/pharmacology , Biological Assay/methods
19.
Int J Mol Sci ; 25(12)2024 Jun 07.
Article in English | MEDLINE | ID: mdl-38928010

ABSTRACT

The identification of novel drug targets in plant-parasitic nematodes (PPNs) is imperative due to the loss of traditional nematicides and a lack of replacements. Chemosensation, which is pivotal for PPNs in locating host roots, has become a focus in nematode behavioral research. However, its underlying molecular basis is still indistinct in such a diverse group of PPNs. To characterize genes participating in chemosensation in the Javanese root-knot nematode Meloidogyne javanica, RNA-sequencing of the second-stage juveniles (J2s) treated with tomato root exudate (TRE) for 1 h and 6 h was performed. Genes related to chemosensation in M. javanica mainly responded to TRE treatment at 1 h. Moreover, a gene ontology (GO) analysis underscored the significance of the neuropeptide G protein-coupled receptor signaling pathway. Consequently, the repertoire of putative neuropeptides in M. javanica, including FMRFamide-like peptides (FLPs), insulin-like peptides (ILPs), and neuropeptide-like peptides (NLPs), were outlined based on a homology analysis. The gene Mjflp-14a, harboring two neuropeptides, was significantly up-regulated at 1 h TRE treatment. Through peptide synthesis and J2 treatment, one of the two neuropeptides (MjFLP-14-2) was proven to influence the J2 chemotaxis towards tomato root tips. Overall, our study reinforces the potential of nematode neuropeptides as novel targets and tools for root-knot nematode control.


Subject(s)
Neuropeptides , Plant Roots , Solanum lycopersicum , Tylenchoidea , Animals , Tylenchoidea/physiology , Neuropeptides/metabolism , Neuropeptides/genetics , Plant Roots/parasitology , Plant Roots/metabolism , Plant Roots/genetics , Solanum lycopersicum/parasitology , Solanum lycopersicum/genetics , Solanum lycopersicum/metabolism , Plant Diseases/parasitology , Plant Diseases/genetics , Chemotaxis , Helminth Proteins/metabolism , Helminth Proteins/genetics
20.
Adv Sci (Weinh) ; 11(30): e2402768, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38874399

ABSTRACT

Efficient neutrophil migration to infection sites plays a vital role in the body's defense against bacterial infections and natural immune responses. Neutrophils have a short lifespan and cannot be mass-cultured in vitro. Therefore, developing more stable artificial neutrophils (AN) in a controllable manner has become a research focus. However, existing AN lack chemotaxis, which is the ability to migrate toward high-signal-concentration positions in a dynamic blood- flow environment. Supplying AN with chemotaxis is key to designing AN that are more similar to natural neutrophils in terms of morphology and function. In this study, micrometer-sized, spherical, biocompatible AN are developed. These AN consist of zeolitic imidazolate framework-8 nanoparticles encapsulating two enzymes, coacervate droplet frameworks, and outer phospholipid bilayers carrying enzymes. The AN exhibit responsiveness to elevated hydrogen peroxide levels at inflammation sites, actively chemotaxing toward these sites along concentration gradients. They also demonstrate effective combat against Staphylococcus aureus infections. The capabilities of the AN are further validated through in vitro experiments and in vivo evaluations using vascular graft infection models. This study replicates natural neutrophils in terms of chemical composition, functionality, and physiological impact. It introduces new ideas for advancing the development of advanced artificial cells.


Subject(s)
Neutrophils , Staphylococcal Infections , Neutrophils/metabolism , Animals , Staphylococcal Infections/immunology , Blood Vessel Prosthesis/adverse effects , Staphylococcus aureus , Mice , Disease Models, Animal , Prosthesis-Related Infections , Nanoparticles/chemistry , Chemotaxis/drug effects , Humans
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