Resident tissue macrophages (RTM) can fulfill various tasks during development, homeostasis, inflammation and repair. In the lung, non-alveolar RTM, called interstitial macrophages (IM), importantly ...contribute to tissue homeostasis but remain little characterized. Here we show, using single-cell RNA-sequencing (scRNA-seq), two phenotypically distinct subpopulations of long-lived monocyte-derived IM, i.e. CD206
and CD206
IM, as well as a discrete population of extravasating CD64
CD16.2
monocytes. CD206
IM are peribronchial self-maintaining RTM that constitutively produce high levels of chemokines and immunosuppressive cytokines. Conversely, CD206
IM preferentially populate the alveolar interstitium and exhibit features of antigen-presenting cells. In addition, our data support that CD64
CD16.2
monocytes arise from intravascular Ly-6C
patrolling monocytes that enter the tissue at steady-state to become putative precursors of CD206
IM. This study expands our knowledge about the complexity of lung IM and reveals an ontogenic pathway for one IM subset, an important step for elaborating future macrophage-targeted therapies.
Influenza A virus (IAV) infections pose a global health challenge that necessitates a comprehensive understanding of the host immune response to devise effective therapeutic interventions. As ...monocytes and macrophages play crucial roles in host defence, inflammation, and repair, this review explores the intricate journey of these cells during and after IAV infection. First, we highlight the dynamics and functions of lung-resident macrophage populations post-IAV. Second, we review the current knowledge of recruited monocytes and monocyte-derived cells, emphasising their roles in viral clearance, inflammation, immunomodulation, and tissue repair. Third, we shed light on the consequences of IAV-induced macrophage alterations on long-term lung immunity. We conclude by underscoring current knowledge gaps and exciting prospects for future research in unravelling the complexities of macrophage responses to respiratory viral infections.
Resident tissue macrophages (RTMs) are differentiated immune cells that populate distinct niches and exert important tissue-supportive functions. RTM maintenance is thought to rely either on ...differentiation from monocytes or on RTM self-renewal. Here, we used a mouse model of inducible lung interstitial macrophage (IM) niche depletion and refilling to investigate the development of IMs in vivo. Using time-course single-cell RNA-sequencing analyses, bone marrow chimeras and gene targeting, we found that engrafted Ly6C
classical monocytes proliferated locally in a Csf1 receptor-dependent manner before differentiating into IMs. The transition from monocyte proliferation toward IM subset specification was controlled by the transcription factor MafB, while c-Maf specifically regulated the identity of the CD206
IM subset. Our data provide evidence that, in the mononuclear phagocyte system, the ability to proliferate is not merely restricted to myeloid progenitor cells and mature RTMs but is also a tightly regulated capability of monocytes developing into RTMs in vivo.
Low exposure to microbial products, respiratory viral infections and air pollution are major risk factors for allergic asthma, yet the mechanistic links between such conditions and host ...susceptibility to type 2 allergic disorders remain unclear. Through the use of single-cell RNA sequencing, we characterized lung neutrophils in mice exposed to a pro-allergic low dose of lipopolysaccharide (LPS) or a protective high dose of LPS before exposure to house dust mites. Unlike exposure to a high dose of LPS, exposure to a low dose of LPS instructed recruited neutrophils to upregulate their expression of the chemokine receptor CXCR4 and to release neutrophil extracellular traps. Low-dose LPS-induced neutrophils and neutrophil extracellular traps potentiated the uptake of house dust mites by CD11b
Ly-6C
dendritic cells and type 2 allergic airway inflammation in response to house dust mites. Neutrophil extracellular traps derived from CXCR4
neutrophils were also needed to mediate allergic asthma triggered by infection with influenza virus or exposure to ozone. Our study indicates that apparently unrelated environmental risk factors can shape recruited lung neutrophils to promote the initiation of allergic asthma.
Nacobbus aberrans
is a plant parasitic nematode that causes significant economic losses in the American Continent and is considered a quarantine pest in many countries. Some arbuscular mycorrhizal ...fungi have shown the ability to reduce the population of this pathogen; however, most studies do not consider other relevant aspects that have to do with the crop or the fungus. The purpose of this work was to select an isolated mycorrhizal fungus based on a comprehensive analysis of the Nematode–Plant–Mycorrhizal Fungus system. The test was conducted on
Solanum lycopersicum
L. grown in pots. The evaluated isolates were
Funneliformis mosseae
,
Rhizoglomus intraradices A2
, and
Rhizoglomus intraradices B1
. All the isolates reduced the nematode population significantly; however, differences in the content of photosynthetic pigments, soluble proteins, and osmoregulatory metabolites were identified. All of these impacted on the photosynthetic rates of the different treatments. There were also differences in the growth of the fungi within the roots, and in the viability of the fungal structures. The comprehensive analysis of the plant–nematode–fungus group allows us to conclude that the isolate with the greatest capacity to compensate for the negative effect of parasitism, and with the greatest possibility of lasting as a biocontrol agent is
Funneliformis mosseae
.
D-Leu
MC-LR and MC-LR, two microcystins differing in one amino acid, constitute a sanitary and environmental problem owing to their frequent and concomitant presence in water bodies of the Americas ...and their association with human intoxication during recreational exposure to cyanobacterial bloom. Present in reservoirs used for irrigation as well, they can generate problems in the development of crops such as
, of nutritional and economic interest to the region. Although numerous works address the toxic effects of MC-LR, information on the toxicity of D-Leu
MC-LR is limited. Our objective was to study the toxic effects of D-Leu
MC-LR and MC-LR (3.5 µg/ml) on
after a single contact at the imbibition stage. Our findings indicate that 10 days post treatment, D-Leu
MC-LR generates morphological and physiological alterations more pronounced than those caused by MC-LR. In addition to the alterations produced by D-Leu
MC-LR in the development of seedlings and the structure of the leaves, roots and stems, we also found alterations in leaf stomatal density and conductivity, a longer delay in the phototropic response and a decrease in the maximum curvature angles achieved with respect to that observed for MC-LR. Our findings indicate that these alterations are linked to the greater inhibition of phosphatase activity generated by D-Leu
MC-LR, rather than to oxidative damage. We observed that 30 days after treatment with MC-LR, plants presented better development and recovery than those treated with D-Leu
MC-LR. Further studies are required on D-Leu
MC-LR and MC-LR toxicity and their underlying mechanisms of action.
La incorporación de metales pesados al medio como modo de contaminación por el uso de fertilizantes y plaguicidas es una de las problemáticas que más preocupan a las organizaciones vinculadas al ...monitoreo del ambiente. El cobre es un micronutriente esencial para el crecimiento vegetal, pero en elevadas concentraciones es tóxico. Las micorrizas arbusculares, participan activamente en el metabolismo de los metales pesados, aumentando la tolerancia de las plantas que crecen en sitios contaminados. Se evaluaron las respuestas morfológicas y fisiológicas de plantas de pimiento inoculadas con el hongo micorrícico arbuscular Funneliformis mosseae en concentraciones crecientes de cobre en un cultivo hidropónico. Se realizaron mediciones morfológicas (peso seco, área foliar), fisiológicas (conductancia y resistencia estomática, índice de verdor, temperatura de hoja, conductividad relativa de membranas celulares) y bioquímicas (patrón proteico, contenido de malondialdehído). Las plantas inoculadas con el hongo micorrícico arbuscular toleraron una concentración mayor de cobre que las no inoculadas y esta concentración varió según el parámetro analizado. En general, en las plantas micorrizadas se observó un aumento del umbral de tolerancia al cobre.
Inoculation with mycorrhizal fungi and the use of rootstock that is tolerant or resistant to nematodes are two strategies that allow the nematode to be controlled, and plants to coexist with the ...pathogen. However, the two techniques have always been tested in isolation, when their positive effects are less compared to when they are able to act together. In the present work, two rootstocks combined with the mycorrhizal fungus Rizophagus intraradices were compared, with the aim of evaluating their behaviour on the growth of tomato plants in soils infested with N. aberrans, the false root-knot nematode. The experiment was set up in a completely randomised design with ten replications, in a 3 x 2 x 2 factorial scheme. The treatments consisted of a combination of three factors: a) plant composition: two rootstocks (Solanum lycopersicum var. cerasiform ‘Carolina’ and S. lycopersicum ‘Maxifort’), onto which the ‘Santa Clara’ tomato (S. lycopersicum) was grafted, and a non-grafted plant, considered the control, which was the same cultivar as the graft; b) mycorrhization: mycorrhizal or non-mycorrhizal roots; c) a substrate infested or not infested with N. aberrans. The plants grafted onto ‘Maxifort’ showed significantly greater growth for shoot dry weight, root fresh weight and stem diameter. The rootstock under test had a lower pathogen reproductive factor than did the ungrafted plant. Mycorrhization contributed to a reduction in the number of days until flowering, and a reduction in the final population of N. aberrans for the three plant compositions under test.
'Nacobbus aberrans', known as the "false root-knot nematode", has drawn special attention since it affects large areas of tomato production in Latin America. The aim of this study was to evaluate two ...rootstocks, 'Solanum lycopersicon' L. var. cerasiforme 'Carolina' and 'S. lycopersicon' L. 'Maxifort', onto which 'S. lycopersicon' L. 'Santa Clara' was grafted. In addition to these, non-grafted 'Santa Clara' plants were used as control. Grafting was carried out 30 days after sowing, both for scion and for root stocks.Both the grafted plants and those used as control were grown in a greenhouse on two kind of substrate: without the presence of ‘N. aberrans’ and inoculated with 5000 eggs. After 60 days of being inoculated, growth parameters, physiological stress indicators, and pathogen reproductive factor were evaluated. The parasitism caused changes in the metabolism of the plants. On grafted plants, flowering was delayed, and on plants exposed to nematodes such delay was even greater. The reproductive factors of the nematode were 3.68, 5.47 and 2.76 on non-grafted rootstocks, 'Carolina' and 'Maxifort', respectively, and they were classified as susceptible. The Maxifort rootstock has an invigorating effect on Santa Clara scion. It stimulates the apical growth and shows a great tolerance to the attack of nematodes as indicated by parameters like the accumulation of proline and the damage in the cell membranes. However, 'N. aberrans' reproduces at its roots and increases its population, so its use as rootstocks must be carried out together with other practices that reduce the reproduction factor of the pathogen.
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