Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 15.913
Filtrar
1.
Methods Mol Biol ; 2364: 327-338, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34542861

RESUMO

The unicellular eukaryotic amoeba, Dictyostelium discoideum, represents a superb model for examining the molecular mechanism of chemotaxis. Under vegetative conditions, the amoebae are chemotactically responsive to pterins, such as folic acid. Under starved conditions, they lose their sensitivity to pterins and become chemotactically responsive to cAMP. As an NIH model system, Dictyostelium offers a variety of advantages in studying chemotaxis, including ease of growth, genetic tractability, and the conservation of mammalian signaling pathways. In this chapter, we describe the use of the under-agarose chemotaxis assay to understand the signaling pathways controlling directional sensing and motility in Dictyostelium discoideum. Given the similarities between Dictyostelium and mammalian cells, this allows us to dissect conserved pathways involved in eukaryotic chemotaxis.


Assuntos
Quimiotaxia , Dictyostelium , Amoeba , Animais , AMP Cíclico , Dictyostelium/genética , Pterinas , Sefarose
2.
Cell Mol Life Sci ; 79(1): 5, 2021 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-34936021

RESUMO

BACKGROUND: Extracellular vesicles (EVs) are regulators of cell-cell interactions and mediators of horizontal transfer of bioactive molecules between cells. EV-mediated cell-cell interactions play roles in physiological and pathophysiological processes, which maybe modulated by exposure to pathogens and cocaine use. However, the effect of pathogens and cocaine use on EV composition and function are not fully understood. RESULTS: Here, we used systems biology and multi-omics analysis to show that HIV infection (HIV +) and cocaine (COC) use (COC +) promote the release of semen-derived EVs (SEV) with dysregulated extracellular proteome (exProtein), miRNAome (exmiR), and exmiR networks. Integrating SEV proteome and miRNAome revealed a significant decrease in the enrichment of disease-associated, brain-enriched, and HIV-associated miR-128-3p (miR-128) in HIV + COC + SEV with a concomitant increase in miR-128 targets-PEAK1 and RND3/RhoE. Using two-dimensional-substrate single cell haptotaxis, we observed that in the presence of HIV + COC + SEV, contact guidance provided by the extracellular matrix (ECM, collagen type 1) network facilitated far-ranging haptotactic cues that guided monocytes over longer distances. Functionalizing SEV with a miR-128 mimic revealed that the strategic changes in monocyte haptotaxis are in large part the result of SEV-associated miR-128. CONCLUSIONS: We propose that compositionally and functionally distinct HIV + COC + and HIV-COC- SEVs and their exmiR networks may provide cells relevant but divergent haptotactic guidance in the absence of chemotactic cues, under both physiological and pathophysiological conditions.


Assuntos
Quimiotaxia , Cocaína/farmacologia , Vesículas Extracelulares/metabolismo , Infecções por HIV/genética , MicroRNAs/metabolismo , Monócitos/metabolismo , Proteoma/metabolismo , Sêmen/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Sequência de Bases , Comorbidade , Redes Reguladoras de Genes , Humanos , MicroRNAs/genética , Pessoa de Meia-Idade , Adulto Jovem
3.
Elife ; 102021 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-34726151

RESUMO

Coordination of diverse individuals often requires sophisticated communications and high-order computational abilities. Microbial populations can exhibit diverse individualistic behaviors, and yet can engage in collective migratory patterns with a spatially sorted arrangement of phenotypes. However, it is unclear how such spatially sorted patterns emerge from diverse individuals without complex computational abilities. Here, by investigating the single-cell trajectories during group migration, we discovered that, despite the constant migrating speed of a group, the drift velocities of individual bacteria decrease from the back to the front. With a Langevin-type modeling framework, we showed that this decreasing profile of drift velocities implies the spatial modulation of individual run-and-tumble random motions, and enables the bacterial population to migrate as a pushed wave front. Theoretical analysis and stochastic simulations further predicted that the pushed wave front can help a diverse population to stay in a tight group, while diverse individuals perform the same type of mean reverting processes around centers orderly aligned by their chemotactic abilities. This mechanism about the emergence of orderly collective migration from diverse individuals is experimentally demonstrated by titration of bacterial chemoreceptor abundance. These results reveal a simple computational principle for emergent ordered behaviors from heterogeneous individuals.


Assuntos
Quimiotaxia , Escherichia coli/fisiologia , Modelos Biológicos , Análise de Célula Única
4.
Dis Markers ; 2021: 6803510, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34603560

RESUMO

Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently the most significant public health threat worldwide. Patients with severe COVID-19 usually have pneumonia concomitant with local inflammation and sometimes a cytokine storm. Specific components of the SARS-CoV-2 virus trigger lung inflammation, and recruitment of immune cells to the lungs exacerbates this process, although much remains unknown about the pathogenesis of COVID-19. Our study of lung type II pneumocyte cells (A549) demonstrated that ORF7, an open reading frame (ORF) in the genome of SARS-CoV-2, induced the production of CCL2, a chemokine that promotes the chemotaxis of monocytes, and decreased the expression of IL-8, a chemokine that recruits neutrophils. A549 cells also had an increased level of IL-6. The results of our chemotaxis Transwell assay suggested that ORF7 augmented monocyte infiltration and reduced the number of neutrophils. We conclude that the ORF7 of SARS-CoV-2 may have specific effects on the immunological changes in tissues after infection. These results suggest that the functions of other ORFs of SARS-CoV-2 should also be comprehensively examined.


Assuntos
COVID-19/metabolismo , Quimiotaxia , Monócitos/patologia , Neutrófilos/patologia , Fases de Leitura Aberta/fisiologia , Pneumonia/patologia , Proteínas Virais/metabolismo , Células A549 , Quimiocina CCL2/metabolismo , Humanos , Técnicas In Vitro , Monócitos/imunologia , Monócitos/metabolismo , Neutrófilos/imunologia , Neutrófilos/metabolismo , Pneumonia/imunologia , Pneumonia/metabolismo , SARS-CoV-2/metabolismo , Proteínas Virais/genética
5.
Nat Commun ; 12(1): 5788, 2021 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-34608163

RESUMO

The chytrid fungal pathogens Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans cause the skin disease chytridiomycosis in amphibians, which is driving a substantial proportion of an entire vertebrate class to extinction. Mitigation of its impact is largely unsuccessful and requires a thorough understanding of the mechanisms underpinning the disease ecology. By identifying skin factors that mediate key events during the early interaction with B. salamandrivorans zoospores, we discovered a marker for host colonization. Amphibian skin associated beta-galactose mediated fungal chemotaxis and adhesion to the skin and initiated a virulent fungal response. Fungal colonization correlated with the skin glycosylation pattern, with cutaneous galactose content effectively predicting variation in host susceptibility to fungal colonization between amphibian species. Ontogenetic galactose patterns correlated with low level and asymptomatic infections in salamander larvae that were carried over through metamorphosis, resulting in juvenile mortality. Pronounced variation of galactose content within some, but not all species, may promote the selection for more colonization resistant host lineages, opening new avenues for disease mitigation.


Assuntos
Anfíbios/microbiologia , Batrachochytrium/patogenicidade , Dermatomicoses/veterinária , Galactose/metabolismo , Pele/metabolismo , Anfíbios/classificação , Anfíbios/crescimento & desenvolvimento , Animais , Batrachochytrium/fisiologia , Biomarcadores/química , Biomarcadores/metabolismo , Carboidratos/química , Quimiotaxia , Dermatomicoses/microbiologia , Resistência à Doença , Galactose/química , Estágios do Ciclo de Vida , Pele/microbiologia , Esporos Fúngicos/patogenicidade , Esporos Fúngicos/fisiologia , Taxa de Sobrevida , Virulência
6.
Nat Immunol ; 22(11): 1375-1381, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34663979

RESUMO

Migration of leukocytes from the skin to lymph nodes (LNs) via afferent lymphatic vessels (LVs) is pivotal for adaptive immune responses1,2. Circadian rhythms have emerged as important regulators of leukocyte trafficking to LNs via the blood3,4. Here, we demonstrate that dendritic cells (DCs) have a circadian migration pattern into LVs, which peaks during the rest phase in mice. This migration pattern is determined by rhythmic gradients in the expression of the chemokine CCL21 and of adhesion molecules in both mice and humans. Chronopharmacological targeting of the involved factors abrogates circadian migration of DCs. We identify cell-intrinsic circadian oscillations in skin lymphatic endothelial cells (LECs) and DCs that cogovern these rhythms, as their genetic disruption in either cell type ablates circadian trafficking. These observations indicate that circadian clocks control the infiltration of DCs into skin lymphatics, a process that is essential for many adaptive immune responses and relevant for vaccination and immunotherapies.


Assuntos
Imunidade Adaptativa , Quimiotaxia , Relógios Circadianos , Células Dendríticas/imunologia , Linfonodos/imunologia , Vasos Linfáticos/imunologia , Pele/imunologia , Idoso , Animais , Moléculas de Adesão Celular/genética , Moléculas de Adesão Celular/metabolismo , Células Cultivadas , Quimiocina CCL21/genética , Quimiocina CCL21/metabolismo , Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/genética , Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/metabolismo , Células Dendríticas/metabolismo , Feminino , Humanos , Linfonodos/metabolismo , Vasos Linfáticos/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Pele/metabolismo , Fatores de Tempo
7.
PLoS One ; 16(10): e0258270, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34653205

RESUMO

Chemokines play diverse and fundamental roles in the immune system and human disease, which has prompted their structural and functional characterisation. Production of recombinant chemokines that are folded and bioactive is vital to their study but is limited by the stringent requirements of a native N-terminus for receptor activation and correct disulphide bonding required to stabilise the chemokine fold. Even when expressed as fusion proteins, overexpression of chemokines in E. coli tends to result in the formation of inclusion bodies, generating the additional steps of solubilisation and refolding. Here we present a novel method for producing soluble chemokines in relatively large amounts via a simple two-step purification procedure with no requirements for refolding. CXCL8 produced by this method has the correct chemokine fold as determined by NMR spectroscopy and in chemotaxis assays was indistinguishable from commercially available chemokines. We believe that this protocol significantly streamlines the generation of recombinant chemokines.


Assuntos
Bioquímica/métodos , Interleucina-8/biossíntese , Interleucina-8/isolamento & purificação , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Quimiotaxia , Humanos , Espectroscopia de Prótons por Ressonância Magnética
8.
Int J Mol Sci ; 22(17)2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34502430

RESUMO

The fertilization of freshwater fish occurs in an environment that may negatively affect the gametes; therefore, the specific mechanisms triggering the encounters of gametes would be highly expedient. The egg and ovarian fluid are likely the major sources of these triggers, which we confirmed here for rainbow trout (Oncorhynchus mykiss). The ovarian fluid affected significantly spermatozoa performance: it supported high velocity for a longer period and changed the motility pattern from tumbling in water to straightforward moving in the ovarian fluid. Rainbow trout ovarian fluid induced a trapping chemotaxis-like effect on activated male gametes, and this effect depended on the properties of the activating medium. The interaction of the spermatozoa with the attracting agents was accompanied by the "turn-and-run" behavior involving asymmetric flagellar beating and Ca2+ concentration bursts in the bent flagellum segment, which are characteristic of the chemotactic response. Ovarian fluid created the optimal environment for rainbow trout spermatozoa performance, and the individual peculiarities of the egg (ovarian fluid)-sperm interaction reflect the specific features of the spawning process in this species.


Assuntos
Quimiotaxia/fisiologia , Fertilização/fisiologia , Oncorhynchus mykiss/metabolismo , Ovário/metabolismo , Espermatozoides/metabolismo , Zigoto/metabolismo , Animais , Sinalização do Cálcio/fisiologia , Feminino , Masculino , Ovário/citologia , Espermatozoides/citologia , Zigoto/citologia
9.
Acta Trop ; 224: 106128, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34509454

RESUMO

Visceral leishmaniasis is caused by the protozoan parasite Leishmania donovani. It is a fatal form of leishmaniasis prevalent in Indian subcontinent. Since there are no human licensed vaccines available for leishmaniasis, chemotherapeutic drugs remain the only means for combating parasitic infections. We have earlier identified a total of 26 amino-acyl tRNA synthetases (aaRS) along with five stand-alone editing domains and two aaRS-associated proteins in Leishmania donovani. In addition to their canonical role of tRNA aminoacylation, aaRS have been involved in novel functions by acquiring novel domains during evolution. The aaRS-associated proteins have been reported to be analogous to a human cytokine, EMAP II, as they possess a modified version of the heptapeptide motif responsible for the cytokine activity. In this manuscript, we report the characterization of two L. donovani aminoacyl-tRNA synthetase associated proteins which showed a human chemokine like activity. Both the proteins, L. donovani EMAP-1 and EMAP-2, possess a modified form of the heptapeptide motif, which is responsible for cytokine activity in human EMAP-2. LdEMAP-1 and LdEMAP-2 were cloned, expressed, and purified. Both LdEMAP-1 and LdEMAP-2 proteins in the promastigote stage were found to be localized in cytoplasm as confirmed by immunofluorescence. In case of L. donovani infected human THP-1 derived macrophages, secretion of LdEMAP-1 and LdEMAP-2 proteins in the cytosol of the macrophages was observed. The role of LdEMAP-1 and LdEMAP-2 in the aminoacylation of rLdTyrRS was also tested and LdEMAP-2 but not LdEMAP-1 increased the rate of aminoacylation of tyrosyl tRNA synthetase (rLdTyrRS). L. donovani EMAP-1 and EMAP-2 proteins managed to exhibit the capability of attracting human origin cells as determined by chemotaxis assay, and also were able to induce the secretion of cytokines from macrophages like their human counterpart (EMAP II). Our working hypothesis is that both of these proteins might be involved in helping the parasite to establish the infection within the host.


Assuntos
Aminoacil-tRNA Sintetases , Leishmania donovani , Aminoacil-tRNA Sintetases/genética , Quimiotaxia , Humanos , Monócitos , Proteínas de Protozoários/genética
10.
Biophys J ; 120(20): 4391-4398, 2021 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-34509505

RESUMO

Flagellated bacteria swim by rotating a bundle of helical flagella and commonly explore the surrounding environment in a "run-and-tumble" motility mode. Here, we show that the upcoming flow could impact the bacterial run-and-tumble behavior by affecting the formation and dispersal of the flagellar bundle. Using a dual optical tweezers setup to trap individual bacteria, we characterized the effects of the imposed fluid flow and cell body rotation on the run-and-tumble behavior. We found that the two factors affect the behavior differently, with the imposed fluid flow increasing the running time and decreasing the tumbling time and the cell body rotation decreasing the tumbling time only. Using numerical simulations, we computed the flagellar bundling time as a function of flow velocity, which agrees well with our experimental observations. The mechanical effects we characterized here provide novel, to our knowledge, ingredients for further studies of bacterial chemotaxis in complex environments such as dynamic fluid environments.


Assuntos
Flagelos , Modelos Biológicos , Quimiotaxia , Pinças Ópticas , Natação
11.
Antonie Van Leeuwenhoek ; 114(11): 1771-1789, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34510303

RESUMO

Understanding the role of chemotaxis in ecological interactions between plants and microbes in the rhizosphere is necessary to optimize biocontrol strategies targeting plant soil-borne diseases. Therefore, we examined and profiled the antagonistic endophytic bacteria (AEB) population with chemotaxis potential in the medicinal plant Panax notoginseng using a cheA gene-based approach coupled with 16S rRNA sequencing. Phylogenetic analysis of the chemotactic AEB (CAEB) community in P. notoginseng enabled the identification of 56 CAEB strains affiliated with 30 species of Actinobacteria, Firmicutes, and Proteobacteria; Firmicutes, especially Bacillus, were predominant. We then systematically quantified the chemotactic response profiles of CAEB toward five organic acid (OA) attractants: citric acid, fumaric acid (FA), malic acid, oxalic acid, and succinic acid. Further hierarchical cluster analysis revealed that the chemotaxis of CAEB to the same attractant exhibited different patterns among not only genera but also species and even strains of the same species. Following chemotaxis and hierarchical analysis, we selected the strongest chemoattractant, fumaric acid (FA), as the target for evaluating the effects of OAs on the representative CAEB strain Bacillus amyloliquefaciens subsp. plantarum YP1. Application of FA significantly stimulated the chemotaxis ability and growth of YP1, and increased the transcript levels of cheA and biocontrol-related genes in YP1. This is the first study to characterise the diversity of chemotaxis profiles toward OAs in natural bacterial assemblages of P. notoginseng and to highlight how FA promotes the biocontrol-related traits of P. notoginseng-associated CAEB.


Assuntos
Endófitos , Panax notoginseng , Bacillus , Bactérias/genética , Quimiotaxia , Endófitos/genética , Filogenia , Raízes de Plantas , RNA Ribossômico 16S/genética
12.
Nano Lett ; 21(19): 8086-8094, 2021 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-34559543

RESUMO

Inspired by the tactic organisms in Nature that can self-direct their movement following environmental stimulus gradient, we proposed a DNase functionalized Janus nanoparticle (JNP) nanomotor system for the first time, which can be powered by ultralow nM to µM levels of DNA. The system exhibited interesting chemotactic behavior toward a DNA richer area, which is physiologically related with many diseases including tumors. In the presence of the subtle DNA gradient generated by apoptotic tumor cells, the cargo loaded nanomotors were able to sense the DNA signal released by the cells and demonstrate directional motion toward tumor cells. For our system, the subtle DNA gradient by a small amount (10 µL) of tumor cells is sufficient to induce the chemotaxis behavior of self-navigating and self-targeting ability of our nanomotor system, which promises to shed new light for tumor diagnosis and therapy.


Assuntos
Quimiotaxia , Neoplasias , DNA , Humanos , Movimento (Física) , Neoplasias/tratamento farmacológico
13.
Int J Mol Sci ; 22(18)2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34575860

RESUMO

Immunosuppressants are a mandatory therapy for transplant patients to avoid rejection of the transplanted organ by the immune system. However, there are several known side effects, including alterations of the vasculature, which involve a higher occurrence of cardiovascular events. While the effects of the commonly applied immunosuppressive drugs cyclosporine A (CsA) and tacrolimus (Tac) on mature endothelial cells have been addressed in several studies, we focused our research on the unexplored effects of CsA and Tac on endothelial colony-forming cells (ECFCs), a subgroup of endothelial progenitor cells, which play an important role in vascular repair and angiogenesis. We hypothesized that CsA and Tac induce functional defects and activate an inflammatory cascade via NF-κB signaling in ECFCs. ECFCs were incubated with different doses (0.01 µM-10 µM) of CsA or Tac. ECFC function was determined using in vitro models. The expression of inflammatory cytokines and adhesion molecules was explored by quantitative real-time PCR and flow cytometry. NF-κB subunit modification was assessed by immunoblot and immunofluorescence. CsA and Tac significantly impaired ECFC function, including proliferation, migration, and tube formation. TNF-α, IL-6, VCAM, and ICAM mRNA expression, as well as PECAM and VCAM surface expression, were enhanced. Furthermore, CsA and Tac led to NF-κB p65 subunit phosphorylation and nuclear translocation. Pharmacological inhibition of NF-κB by parthenolide diminished CsA- and Tac-mediated proinflammatory effects. The data of functional impairment and activation of inflammatory signals provide new insight into mechanisms associated with CsA and Tac and cardiovascular risk in transplant patients.


Assuntos
Ciclosporina/farmacologia , Células Endoteliais/efeitos dos fármacos , Inflamação/tratamento farmacológico , Células-Tronco/efeitos dos fármacos , Tacrolimo/farmacologia , Doenças Cardiovasculares/tratamento farmacológico , Doenças Cardiovasculares/imunologia , Movimento Celular , Proliferação de Células , Quimiotaxia , Citocinas/metabolismo , Células Progenitoras Endoteliais/efeitos dos fármacos , Humanos , Imunossupressores , Molécula 1 de Adesão Intercelular/metabolismo , Interleucina-6/metabolismo , NF-kappa B/metabolismo , Subunidade p50 de NF-kappa B/metabolismo , Neovascularização Patológica , Sesquiterpenos/farmacologia , Transdução de Sinais , Fator de Necrose Tumoral alfa/metabolismo , Molécula 1 de Adesão de Célula Vascular/metabolismo
14.
Int J Mol Sci ; 22(18)2021 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-34576243

RESUMO

Fetal bovine serum (FBS) is the only known stimulus for the migration of human neural crest cells (NCCs). Non-animal chemoattractants are desirable for the optimization of chemotaxis as-says to be incorporated in a test battery for reproductive and developmental toxicity. We con-firmed here in an optimized transwell assay that FBS triggers directed migration along a con-centration gradient. The responsible factor was found to be a protein in the 30-100 kDa size range. In a targeted approach, we tested a large panel of serum constituents known to be chem-otactic for NCCs in animal models (e.g., VEGF, PDGF, FGF, SDF-1/CXCL12, ephrins, endothelin, Wnt, BMPs). None of the corresponding human proteins showed any effect in our chemotaxis assays based on human NCCs. We then examined, whether human cells would produce any fac-tor able to trigger NCC migration in a broad screening approach. We found that HepG2 hepa-toma cells produced chemotaxis-triggering activity (CTA). Using chromatographic methods and by employing the NCC chemotaxis test as bioassay, the responsible protein was enriched by up to 5000-fold. We also explored human serum and platelets as a direct source, independent of any cell culture manipulations. A CTA was enriched from platelet lysates several thousand-fold. Its temperature and protease sensitivity suggested also a protein component. The capacity of this factor to trigger chemotaxis was confirmed by single-cell video-tracking analysis of migrating NCCs. The human CTA characterized here may be employed in the future for the setup of assays testing for the disturbance of directed NCC migration by toxicants.


Assuntos
Plaquetas/metabolismo , Fatores Quimiotáticos/metabolismo , Quimiotaxia , Crista Neural/metabolismo , Soroalbumina Bovina/química , Técnicas de Cultura de Células , Diferenciação Celular , Movimento Celular , Proliferação de Células , Células Hep G2 , Humanos , Técnicas In Vitro , Transdução de Sinais
15.
Cells ; 10(9)2021 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-34572122

RESUMO

There is considerable evidence that female reproductive fluid (FRF) interacts intimately with sperm, affecting several sperm traits, including sperm motility and longevity, and ultimately fertilization success. One of the first documented interactions between FRF and sperm is the ability of FRF to attract and guide sperm towards the eggs. However, most of the evidence of FRF's chemoattraction proprieties comes from a limited number of taxa, specifically mammals and invertebrate broadcasting spawners. In other species, small FRF volumes and/or short sperm longevity often impose methodological difficulties resulting in this gap in chemoattraction studies in non-model species. One of the outcomes of sperm chemotaxis is sperm accumulation towards high chemoattractant concentrations, which can be easily quantified by measuring sperm concentration. Here, we tested sperm accumulation towards FRF in the zebrafish, Danio rerio, using an ad hoc developed, 3D printed, device ('sperm selection chamber'). This easy-to-use tool allows to select and collect the sperm that swim towards a chemical gradient, and accumulate in a chemoattractant-filled well thus providing putative evidence for chemoattraction. We found that sperm accumulate in FRF in zebrafish. We also found that none of the sperm quality traits we measured (sperm swimming velocity and trajectory, sperm motility, and longevity) were correlated with this response. Together with the 3D printable project, we provide a detailed protocol for using the selection chamber. The chamber is optimized for the zebrafish, but it can be easily adapted for other species. Our device lays the foundation for a standardized way to measure sperm accumulation and in general chemoattraction, stimulating future research aimed at understanding the role and the mechanisms of sperm chemoattraction by FRF.


Assuntos
Secreções Corporais/metabolismo , Fatores Quimiotáticos/metabolismo , Quimiotaxia , Genitália Feminina/fisiologia , Motilidade Espermática , Espermatozoides/fisiologia , Animais , Feminino , Masculino , Espermatozoides/efeitos dos fármacos , Peixe-Zebra
16.
Cells ; 10(9)2021 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-34572130

RESUMO

BACKGROUND: Whole transgenic or non-transgenic organism model systems allow the screening of pharmacological compounds for protective actions in Alzheimer's disease (AD). AIM: In this study, a plant parasitic nematode, Globodera pallida, which assimilates intact peptides from the external environment, was investigated as a new potential non-transgenic model system of AD. Methods: Fresh second-stage juveniles of G. pallida were used to measure their chemosensory, perform immunocytochemistry on their neurological structures, evaluate their survival rate, measure reactive oxygen species, and determine total oxidized glutathione to reduced glutathione ratio (GSSG/GSH) levels, before and after treatment with 100 µM of various amyloid beta (Aß) peptides (1-40, 1-42, 17-42, 17-40, 1-28, or 1-16). Wild-type N2 C. elegans (strain N2) was cultured on Nematode Growth Medium and directly used, as control, for chemosensory assays. RESULTS: We demonstrated that: (i) G. pallida (unlike Caenorhabditis elegans) assimilates amyloid-ß (Aß) peptides which co-localise with its neurological structures; (ii) pre-treatment with various Aß isoforms (1-40, 1-42, 17-42, 17-40, 1-28, or 1-16) impairs G. pallida's chemotaxis to differing extents; (iii) Aß peptides reduced survival, increased the production of ROS, and increased GSSG/GSH levels in this model; (iv) this unique model can distinguish differences between different treatment concentrations, durations, and modalities, displaying good sensitivity; (v) clinically approved neuroprotective agents were effective in protecting G. pallida from Aß (1-42) exposure. Taken together, the data indicate that G. pallida is an interesting in vivo model with strong potential for discovery of novel bioactive compounds with anti-AD activity.


Assuntos
Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/toxicidade , Animais Geneticamente Modificados/fisiologia , Fármacos Neuroprotetores/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Tylenchoidea/fisiologia , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/fisiologia , Quimiotaxia , Tylenchoidea/efeitos dos fármacos
17.
Nat Commun ; 12(1): 5442, 2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34521846

RESUMO

Reversible switching of the bacterial flagellar motor between clockwise (CW) and counterclockwise (CCW) rotation is necessary for chemotaxis, which enables cells to swim towards favorable chemical habitats. Increase in the viscous resistance to the rotation of the motor (mechanical load) inhibits switching. However, cells must maintain homeostasis in switching to navigate within environments of different viscosities. The mechanism by which the cell maintains optimal chemotactic function under varying loads is not understood. Here, we show that the flagellar motor allosterically controls the binding affinity of the chemotaxis response regulator, CheY-P, to the flagellar switch complex by modulating the mechanical forces acting on the rotor. Mechanosensitive CheY-P binding compensates for the load-induced loss of switching by precisely adapting the switch response to a mechanical stimulus. The interplay between mechanical forces and CheY-P binding tunes the chemotactic function to match the load. This adaptive response of the chemotaxis output to mechanical stimuli resembles the proprioceptive feedback in the neuromuscular systems of insects and vertebrates.


Assuntos
Proteínas de Bactérias/metabolismo , Escherichia coli/metabolismo , Flagelos/metabolismo , Proteínas Quimiotáticas Aceptoras de Metil/metabolismo , Regulação Alostérica , Animais , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Mimetismo Biológico , Fenômenos Biomecânicos , Quimiotaxia/genética , Escherichia coli/genética , Escherichia coli/ultraestrutura , Proteínas de Escherichia coli , Retroalimentação Sensorial/fisiologia , Flagelos/genética , Flagelos/ultraestrutura , Expressão Gênica , Insetos/fisiologia , Proteínas Quimiotáticas Aceptoras de Metil/química , Proteínas Quimiotáticas Aceptoras de Metil/genética , Pinças Ópticas , Ligação Proteica , Vertebrados/fisiologia , Viscosidade
18.
Nat Commun ; 12(1): 5462, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34526503

RESUMO

Salicylic acid is a phenolic phytohormone which controls plant growth and development. A methyl ester (MSA) derivative thereof is volatile and involved in plant-insect or plant-plant communication. Here we show that the nematode-trapping fungus Duddingtonia flagrans uses a methyl-salicylic acid isomer, 6-MSA as morphogen for spatiotemporal control of trap formation and as chemoattractant to lure Caenorhabditis elegans into fungal colonies. 6-MSA is the product of a polyketide synthase and an intermediate in the biosynthesis of arthrosporols. The polyketide synthase (ArtA), produces 6-MSA in hyphal tips, and is uncoupled from other enzymes required for the conversion of 6-MSA to arthrosporols, which are produced in older hyphae. 6-MSA and arthrosporols both block trap formation. The presence of nematodes inhibits 6-MSA and arthrosporol biosyntheses and thereby enables trap formation. 6-MSA and arthrosporols are thus morphogens with some functions similar to quorum-sensing molecules. We show that 6-MSA is important in interkingdom communication between fungi and nematodes.


Assuntos
Ascomicetos/fisiologia , Caenorhabditis elegans/fisiologia , Hifas/fisiologia , Comportamento Predatório/fisiologia , Ácido Salicílico/metabolismo , Animais , Ascomicetos/genética , Ascomicetos/metabolismo , Quimiotaxia/fisiologia , Proteínas Fúngicas/metabolismo , Hifas/genética , Hifas/metabolismo , Policetídeo Sintases/metabolismo , Ácido Salicílico/química , Esporos Fúngicos/genética , Esporos Fúngicos/metabolismo
19.
Int J Mol Sci ; 22(17)2021 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-34502014

RESUMO

In echinoderms, sperm swims in random circles and turns in response to a chemoattractant. The chemoattractant evokes transient Ca2+ influx in the sperm flagellum and induces turning behavior. Recently, the molecular mechanisms and biophysical properties of this sperm response have been clarified. Based on these experimental findings, in this study, we reconstructed a sperm model in silico to demonstrate an algorithm for sperm chemotaxis. We also focused on the importance of desensitizing the chemoattractant receptor in long-range chemotaxis because sperm approach distantly located eggs, and they must sense the chemoattractant concentration over a broad range. Using parameters of the sea urchin, simulations showed that a number of sperm could reach the egg from millimeter-order distances with desensitization, indicating that we could organize a functional sperm model, and that desensitization of the receptor is essential for sperm chemotaxis. Then, we compared the model with starfish sperm, which has a different desensitization scheme and analyzed the properties of the model against various disturbances. Our approach can be applied as a novel tool in chemotaxis research.


Assuntos
Asterias/fisiologia , Quimiotaxia , Simulação por Computador , Modelos Biológicos , Espermatozoides/fisiologia , Animais , Fertilização , Masculino
20.
Int J Mol Sci ; 22(17)2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34502263

RESUMO

The regulator of G protein signaling (RGS) represents a widespread system of controllers of cellular responses. The activities of the R4 subfamily of RGSs have been elucidated in allergic pulmonary diseases. However, the R4 signaling in other inflammatory lung diseases, with a strong cellular immune response, remained unexplored. Thus, our study aimed to discern the functional relevance of the R4 family member, RGS5, as a potential modulating element in this context. Gene profiling of the R4 subfamily showed increased RGS5 expression in human fibrosing lung disease samples. In line with this, RGS5 was markedly increased in murine lungs following bleomycin injury. RGS knock-out mice (RGS-/-) had preserved lung function while control mice showed significant combined ventilatory disorders three days after bleomycin application as compared to untreated control mice. Loss of RGS5 was associated with a significantly reduced neutrophil influx and tissue myeloperoxidase expression. In the LPS lung injury model, RGS5-/- mice also failed to recruit neutrophils into the lung, which was accompanied by reduced tissue myeloperoxidase levels after 24 h. Our in-vitro assays showed impaired migration of RGS5-/- neutrophils towards chemokines despite preserved Ca2+ signaling. ERK dephosphorylation might play a role in reduced neutrophil migration in our model. As a conclusion, loss of RGS5 preserves lung function and attenuates hyperinflammation in the acute phase of bleomycin-induced pulmonary fibrosis and LPS-induced lung injury. Targeting RGS5 might alleviate the severity of exacerbations in interstitial lung diseases.


Assuntos
Inflamação/metabolismo , Lesão Pulmonar/metabolismo , Neutrófilos/metabolismo , Proteínas RGS/genética , Proteínas RGS/metabolismo , Animais , Bleomicina/toxicidade , Quimiotaxia/genética , Modelos Animais de Doenças , Fibrose/genética , Humanos , Inflamação/induzido quimicamente , Lipopolissacarídeos/toxicidade , Doenças Pulmonares Intersticiais/genética , Doenças Pulmonares Intersticiais/metabolismo , Doenças Pulmonares Intersticiais/patologia , Lesão Pulmonar/induzido quimicamente , Lesão Pulmonar/patologia , Sistema de Sinalização das MAP Quinases/genética , Camundongos , Camundongos Knockout , Neutrófilos/citologia , Proteínas RGS/deficiência , Síndrome do Desconforto Respiratório/genética , Síndrome do Desconforto Respiratório/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...