The relative contribution of induced and natural Foxp3+ regulatory T cells (iTreg and nTreg cells, respectively) to the maintenance of tolerance is unknown. We examined their respective roles by in vivo adoptive transfer immunotherapy of newborn Foxp3-deficient BALB/c mice. Survival, weight gain, tissue infiltration, T cell activation, and the concentration of proinflammatory cytokines were used as outcome measurements. Treatment with iTreg cells alone was not successful. While effective in preventing death, treatment with nTreg cells alone was associated with chronic inflammation and autoimmunity. Outcomes markedly improved when conventional T (Tconv) cells were transferred together with the nTreg cells, where 10% of the peripheral Treg cell pool was derived by in-situ conversion. This enhancement depended upon the capacity of Tconv cells to express Foxp3.
A requisite role for induced regulatory T cells in tolerance based on expanding antigen receptor diversity.
Age, Specimen part
View SamplesChronic obstructive pulmonary disease (COPD) is a heterogenous respiratory disease mainly caused by smoking. Respiratory infections constitute a major risk factor for acute worsening of COPD symptoms or COPD exacerbation. Mitochondrial functionality, which is crucial for the execution of physiologic functions of metabolically active cells, is impaired in airway epithelial cells (AECs) of COPD patients as well as smokers. However, the potential contribution of mitochondrial dysfunction in AECs to progression of COPD, infection-triggered exacerbations in AECs and a potential mechanistic link between mitochondrial and epithelial barrier dysfunction is unknown to date. In this study, we used an in vitro COPD exacerbation model based on AECs exposed to cigarette smoke extract (CSE) followed by infection with Streptococcus pneumoniae (Sp). The levels of oxidative stress, as an indicator of mitochondrial stress were quantified upon CSE and Sp. The expression of proteins associated with mitophagy, mitochondrial content and biogenesis as well as mitochondrial fission and fusion was quantified upon CSE and Sp. Transcriptional AEC profiling was performed to identify the potential changes in innate immune pathways and correlate them with mitochondrial function. We found that CSE exposure substantially altered mitochondrial function in AECs by suppressing mitochondrial complex protein levels, reducing mitochondrial membrane potential and increasing mitochondrial stress and mitophagy. Moreover, CSE-induced mitochondrial dysfunction correlated with reduced enrichment of genes involved in apical junctions and innate immune responses to Sp, particularly type I interferon responses. Together, our results demonstrated that CSE-induced mitochondrial dysfunction may contribute to impaired innate immune responses to Sp and may thus trigger COPD exacerbation.
Cigarette Smoke Extract Disturbs Mitochondria-Regulated Airway Epithelial Cell Responses to Pneumococci.
Specimen part, Cell line, Treatment
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