Defective efferocytosis in the airway may perpetuate inflammation in smokers with/without chronic obstructive pulmonary disease. Mannose-binding lectin (MBL) improves efferocytosis in vitro; however, the effects of in vivo administration are unknown. MBL circulates in complex with MBL-associated serine proteases (MASPs), and efferocytosis involves activation of cytoskeletal-remodeling molecules, including Rac1/2/3. We hypothesized that MBL would improve efferocytosis in vivo, and that possible mechanisms for this effect would include up-regulation of Rac1/2/3 or MASPs. We used a smoking mouse model to investigate the effects of MBL on efferocytosis. MBL (20 microg/20 g mouse) was administered via nebulizer to smoke-exposed mice. In lung tissue (disaggregated) and bronchoalveolar lavage (BAL), we investigated leukocyte counts, apoptosis, and the ability of alveolar and tissue macrophages to phagocytose apoptotic murine epithelial cells. In human studies, flow cytometry, ELISA, and RT-PCR were used to investigate the effects of MBL on efferocytosis, Rac1/2/3, and MASPs. Smoke-exposed mice showed significantly reduced efferocytosis in BAL and tissue. Efferocytosis was significantly improved by MBL (BAL: control, 26.2%; smoke-exposed, 17.66%; MBL + smoke-exposed, 27.8%; tissue: control, 35.9%; smoke-exposed, 21.6%; MBL + smoke-exposed, 34.5%). Leukocyte/macrophage counts were normalized in smoke-exposed mice treated with MBL. In human studies, MBL was reduced in chronic obstructive pulmonary disease and in smokers, and was significantly correlated with reduced efferocytosis ex vivo. MASPs were not detected in BAL, and were not produced by alveolar or tissue macrophages. MBL significantly increased macrophage expression of Rac1/2/3. We provide evidence for Rac1/2/3 involvement in the MBL-mediated improvement in efferocytosis, and a rationale for investigating MBL as a supplement to existing therapies in smoking-related lung inflammation.
This research output has an Altmetric Attention Score of 4. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 22 January 2024.
All research outputs
#10,783,131
of 34,526,284 outputs
Outputs from American Journal of Respiratory Cell and Molecular Biology
#1,621
of 4,380 outputs
Outputs of similar age
#68,446
of 234,065 outputs
Outputs of similar age from American Journal of Respiratory Cell and Molecular Biology
#13
of 22 outputs
Altmetric has tracked 34,526,284 research outputs across all sources so far. This one has received more attention than most of these and is in the 67th percentile.
So far Altmetric has tracked 4,380 research outputs from this source. They typically receive a little more attention than average, with a mean Attention Score of 6.0. This one has gotten more attention than average, scoring higher than 61% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 234,065 tracked outputs that were published within six weeks on either side of this one in any source. This one has gotten more attention than average, scoring higher than 68% of its contemporaries.
We're also able to compare this research output to 22 others from the same source and published within six weeks on either side of this one. This one is in the 40th percentile – i.e., 40% of its contemporaries scored the same or lower than it.
