mBio. 2023 Mar 22:e0332622. doi: 10.1128/mbio.03326-22. Online ahead of print.

ABSTRACT

The Gram-negative opportunistic pathogen Pseudomonas aeruginosa is a leading cause of infections and mortality in immunocompromised patients. This organism can overcome iron deprivation during infection via the synthesis of two iron-chelating siderophores, pyoverdine and pyochelin, which scavenge iron from host proteins. P. aeruginosa can also uptake xenosiderophores produced by other bacteria or fungi using dedicated transporter systems. The precise substrate specificity of these siderophore transporters remains to be determined. The thiopeptide antibiotic thiostrepton exploits the pyoverdine transporters FpvA and FpvB to cross the outer membrane and reach intracellular targets. Using a series of intricate biochemical experiments, a recent study by Chan and Burrows capitalized on the specificity of thiostrepton to uncover that FpvB transports the xenosiderophores ferrichrome and ferrioxamine B with higher affinity than pyoverdine. This surprising result highlights an alternative uptake pathway for these siderophores and has significant implications for our understanding of iron acquisition in this organism.

PMID:36946760 | DOI:10.1128/mbio.03326-22

Ann Am Thorac Soc. 2023 Mar 21. doi: 10.1513/AnnalsATS.202208-684OC. Online ahead of print.

ABSTRACT

RATIONALE: Lumacaftor/ivacaftor (LUM/IVA) was shown to be safe and well tolerated in children 2 through 5 years of age with cystic fibrosis (CF) homozygous for F508del-CFTR in a phase 3 open-label study. Improvements in sweat chloride concentration, markers of pancreatic function, and lung clearance index2.5 (LCI2.5), along with increases in growth parameters, suggested the potential for early disease modification with LUM/IVA treatment.

OBJECTIVE: To further assess the effects of LUM/IVA on CF disease progression in children 2 through 5 years of age using chest magnetic resonance imaging (MRI).

METHODS: This phase 2 study had two parts: a 48-week, randomized, double-blind, placebo-controlled treatment period in which children 2 through 5 years of age with CF homozygous for F508del-CFTR received either LUM/IVA or placebo (Part 1) followed by an open-label period in which all children received LUM/IVA for an additional 48 weeks (Part 2). We report results from Part 1. The primary endpoint was absolute change from baseline in chest MRI global score at Week 48. Secondary endpoints included absolute change in LCI2.5 through Week 48 and absolute changes in weight-for-age, stature-for-age, and body mass index-for-age z-scores at Week 48. Additional endpoints included absolute changes in sweat chloride concentration, fecal elastase-1 levels, serum immunoreactive trypsinogen, and fecal calprotectin through Week 48. The primary endpoint was analyzed using Bayesian methods, where the actual Bayesian posterior probability of LUM/IVA being superior to placebo in the MRI global chest score at Week 48 was calculated using a vague normal prior distribution; secondary and additional endpoints were analyzed using descriptive summary statistics.

RESULTS: Fifty-one children were enrolled and received LUM/IVA (n=35) or placebo (n=16). For the change in MRI global chest score at Week 48, the Bayesian posterior probability of LUM/IVA being better than placebo (treatment difference <0; higher score indicating greater abnormality) was 76%; the mean treatment difference was -1.5 (95% credible interval, -5.5 to 2.6). Treatment with LUM/IVA also led to within-group numerical improvements in LCI2.5, growth parameters, and biomarkers of pancreatic function as well as greater decreases in sweat chloride concentration compared with placebo from baseline through Week 48. Safety data were consistent with the established safety profile of LUM/IVA.

CONCLUSIONS: This placebo-controlled study suggests the potential for early disease modification with LUM/IVA treatment, including that assessed by chest MRI, in children as young as 2 years. Clinical trial registered with ClinicalTrials.gov (NCT03625466).

PMID:36943405 | DOI:10.1513/AnnalsATS.202208-684OC

Can J Gastroenterol Hepatol. 2023 Mar 11;2023:2877350. doi: 10.1155/2023/2877350. eCollection 2023.

ABSTRACT

BACKGROUND: Ataxia-telangiectasia (A-T) is a rare autosomal-recessive multisystem disorder characterized by pronounced cerebellar ataxia, telangiectasia, cancer predisposition, and altered body composition. Liver diseases with steatosis, fibrosis, and hepatocellular carcinoma are frequent findings in older patients but sensitive noninvasive diagnostic tools are lacking.

OBJECTIVES: To determine the sensitivity of transient elastography (TE) as a screening tool for early hepatic tissue changes and serum biomarkers for liver disease.

METHODS: Thirty-one A-T patients aged 2 to 25 years were examined prospectively from 2016-2018 by TE. In addition, we evaluated the diagnostic performance of liver biomarkers for steatosis and necroinflammatory activity (SteatoTest and ActiTest, Biopredictive, Paris) compared to TE. For calculation and comparison, patients were divided into two groups (<12, >12 years of age).

RESULTS: TE revealed steatosis in 2/21 (10%) younger patients compared to 9/10 (90%) older patients. Fibrosis was present in 3/10 (30%) older patients as assessed by TE. We found a significant correlation of steatosis with SteatoTest, alpha-fetoprotein (AFP), HbA1c, and triglycerides. Liver stiffness correlated significantly with SteatoTest, ActiTest, HbA1c, and triglycerides.

CONCLUSION: Liver disease is a common finding in older A-T patients. TE is an objective measure to detect early stages of steatosis and fibrosis. SteatoTest and ActiTest are a good diagnostic assessment for steatosis and necroinflammatory activity in patients with A-T and confirmed the TE results.

PMID:36941982 | PMC:PMC10024628 | DOI:10.1155/2023/2877350

Orphanet J Rare Dis. 2023 Mar 20;18(1):62. doi: 10.1186/s13023-023-02671-z.

ABSTRACT

Cystic fibrosis (CF) is the most common genetic disease in the Caucasion population. Thanks to the CFTR modulators therapy, life expectancy will significantly improve. New therapeutic challenges can be expected, including diseases associated with ageing and higher incidence of cancer, as evidenced by recent epidemiological studies. The increasing incidence of tumors includes also breast cancer. The risk of breast cancer is higher in CF patients compared to the general population. Sex hormones, especially estrogens, also affect on the pathophysiology and immunology of the CF. Previous research, has demonstrated unequivocal survival rates for female CF patients compared to their male counterparts. Is demonstrated, that chemotherapy used for breast cancer affects the CFTR channel and CFTR modulator therapy has frequent side effects on breast tissue. In this review, we focus on the effects of female sex hormones on CF disease, pathophysiological relationships between CF and breast cancer, and the impact of antitumor treatment on both, malignant disease and CF. The potential for further investigation is also discussed.

PMID:36941680 | DOI:10.1186/s13023-023-02671-z

Med Clin (Barc). 2023 Mar 18:S0025-7753(23)00067-2. doi: 10.1016/j.medcli.2023.01.021. Online ahead of print.

NO ABSTRACT

PMID:36941162 | DOI:10.1016/j.medcli.2023.01.021

Mol Diagn Ther. 2023 Mar 20. doi: 10.1007/s40291-023-00644-3. Online ahead of print.

ABSTRACT

BACKGROUND: Cystic fibrosis (CF) is a genetic disease characterized by multi-system dysfunction resulting in recurrent lung infections and progressive pulmonary disease. CF patients are at a higher risk for drug hypersensitivity reactions (DHRs) compared to the general population, which has been attributed to the recurrent need for antibiotics and the inflammation associated with CF disease. In vitro toxicity tests such as the lymphocyte toxicity assay (LTA) offer the potential for risk assessment for DHRs. In the current study, we investigated the utility of the LTA test for diagnosis of DHRs in a cohort of CF patients.

METHOD: Twenty CF patients with suspected DHRs to sulfamethoxazole, penicillins, cephalosporins, meropenem, vancomycin, rifampicin, and tobramycin were recruited to this study and tested using the LTA test along with 20 healthy control volunteers. Demographic data of the patients, including age, sex, and medical history, were obtained. Blood samples were withdrawn from patients and healthy volunteers, and the LTA test was performed on isolated peripheral blood monocytes (PBMCs) from those individuals.

RESULTS: Cells from CF patients with DHRs displayed a significant (p < 0.0001) concentration-dependent enhanced cell death upon incubation with the culprit drug compared to cells from healthy volunteers. The positivity rate of the LTA test was over 80% in patients with a medical history and clinical presentation consistent with DHRs.

CONCLUSION: This study is the first to evaluate the use of the LTA test for diagnosis of DHRs in CF patients. According to our results, the LTA test may be a useful tool for diagnosis and management of DHRs in CF patients. Identifying the culprit drug is essential for optimal healthcare for CF patients in the setting of a suspected DHR. The data also provide evidence that accumulation of toxic reactive metabolites could be an important component in the cascade of events leading to the development of DHRs in CF patients. A larger-scale study is needed to confirm the data.

PMID:36939981 | DOI:10.1007/s40291-023-00644-3

Clin Respir J. 2023 Mar 20. doi: 10.1111/crj.13602. Online ahead of print.

ABSTRACT

INTRODUCTION: Ivacaftor has shown to be effective in patients with cystic fibrosis (CF) with a G551D mutation.

OBJECTIVES: This work aims to evaluate ivacaftor's effectiveness and safety in the real world, over 5 years, in the West of Scotland CF population.

METHODS: We evaluated ivacaftor's effect on pulmonary function, body mass index (BMI), hospital bed occupancy, and adverse effects in patients ≥6 years with at least one G551D mutation.

RESULTS: Statistically significant increases from baseline were observed in mean per cent predicted forced expiratory volume in 1 s (FEV1 ) at year 1 (which was maintained at years 2 and 5) and BMI over 5 years in our adolescent/adult cohort. Improvements were observed in per cent predicted FEV1 within the paediatric cohort with a suggestion of a plateau effect. The increase in paediatric BMI z-score was nonstatistically significant. There was a reduction in the number of pulmonary exacerbations requiring intravenous antibiotics and hospital bed occupancy. Ivacaftor was well tolerated.

CONCLUSION: Ivacaftor was effective in our population.

PMID:36938952 | DOI:10.1111/crj.13602

J Surg Case Rep. 2023 Mar 17;2023(3):rjad117. doi: 10.1093/jscr/rjad117. eCollection 2023 Mar.

ABSTRACT

Cystic fibrosis (CF) is commonly associated with gastrointestinal manifestations from infancy to adulthood. Distal intestinal obstruction syndrome (DIOS) affects 20% of CF patients, where intussusception can be a rare complication. A 20-year-old CF male was diagnosed with a 3-day history of right iliac fossa pain and diarrhoea. Clinical examination revealed a tender palpable mass in the right iliac fossa and raised serum inflammatory markers. Contrast computerized-tomography of the abdomen-pelvis suggested intussusception of the appendix and further confirmed on histological analyses. The patient underwent an open appendicectomy where the intussusception had self-resolved. The literature review indicated a scarcity of data with 10 cases reported of intussusception in adult CF patients. Our case was in line with previous research of transient intussusception. This rare case highlights an importance to carry a higher index of suspicion for gastrointestinal manifestations in CF patients where differential diagnoses of DIOS and intussusception should be considered in the acute presentation.

PMID:36937795 | PMC:PMC10023239 | DOI:10.1093/jscr/rjad117

Front Immunol. 2023 Mar 1;14:1117749. doi: 10.3389/fimmu.2023.1117749. eCollection 2023.

ABSTRACT

Immunoglobulin A (IgA) is the most abundant Ig in mucosae where it plays key roles in host defense against pathogens and in mucosal immunoregulation. Whereas intense research has established the different roles of secretory IgA in the gut, its function has been much less studied in the lung. This review will first summarize the state-of-the-art knowledge on the distribution and phenotype of IgA+ B cells in the human lung in both homeostasis and disease. Second, it will analyze the studies looking at cellular and molecular mechanisms of homing and priming of IgA+ B cells in the lung, notably following immunization. Lastly, published data on observations related to IgA and IgA+ B cells in lung and airway disease such as asthma, cystic fibrosis, idiopathic pulmonary fibrosis, or chronic rhinosinusitis, will be discussed. Collectively it provides the state-of-the-art of our current understanding of the biology of IgA-producing cells in the airways and identifies gaps that future research should address in order to improve mucosal protection against lung infections and chronic inflammatory diseases.

PMID:36936934 | PMC:PMC10014553 | DOI:10.3389/fimmu.2023.1117749

J Patient Exp. 2023 Mar 15;10:23743735231161486. doi: 10.1177/23743735231161486. eCollection 2023.

ABSTRACT

To prevent or mitigate chronic illness burden, people with cystic fibrosis (pwCF) and their family caregivers need primary (generalist-level) palliative care from the time of diagnosis forward. We used qualitative methods to explore their preferences about a screening-and-triage model ("Improving Life with CF") developed to standardize this care. We purposively sampled and interviewed 14 pwCF and caregivers from 5 Improving Life with CF study sites. Thematic analysis was guided by a priori codes using the National Consensus Project's Guidelines for Quality Palliative Care. Participants included 7 adults and 2 adolescents with CF (3 with advanced disease), 4 parents, 1 partner (7 women; 5 people of color). Few were familiar with palliative care. Illness burden was described in multiple domains, including physical (e.g., dyspnea, pain), psychological (e.g., anxiety), and social (e.g., family well-being; impact on work/school). Most preferred survey-based screening with care coordination by the CF team. Preferences for screening approaches varied. PwCF and caregivers experience illness burden and are receptive to a CF-team delivered primary palliative care screening-and-triage model with flexible processes.

PMID:36936380 | PMC:PMC10021085 | DOI:10.1177/23743735231161486

Ther Clin Risk Manag. 2023 Mar 13;19:255-267. doi: 10.2147/TCRM.S391476. eCollection 2023.

ABSTRACT

BACKGROUND: Association between dependence on oxygen therapy (OT) and natural disease progression in people with cystic fibrosis (pwCF) has not been estimated yet. The aim of this study is to understand the prognosis for pwCF on OT, evaluating how the transition probabilities from being alive without lung transplantation (LTx) to LTx and to death, and from being alive after LTx to death change in pwCF with and without OT.

METHODS: We used 2008-2017 data from the 35-country European CF Society Patient Registry. A multi-state model was fitted to assess the effects of individual risk factors on transition probabilities.

RESULTS: We considered 48,343 pwCF aged from 6 to 50 years. OT (HR 5.78, 95% CI: 5.32-6.29) and abnormal FEV1 (HR 6.41, 95% CI: 5.28-7.79) were strongly associated with the probability of having LTx; chronic infection with Burkholderia cepacia complex (HR 3.19, 95% CI: 2.78-3.67), abnormal FEV1 (HR 5.00, 95% CI: 4.11-6.08) and the need for OT (HR 4.32, 95% CI: 3.93-4.76) showed the greatest association with the probability of dying without LTx. Once pwCF received LTx, OT (HR 1.75, 95% CI: 1.41-2.16) and abnormal FEV1 (HR 1.63, 95% CI: 1.18-2.25) were the main factors associated with the probability of dying. An association of gross national income with the probability of receiving LTx and with the probability of dying without LTx was also found.

CONCLUSION: Oxygen therapy is associated with poor survival in pwCF with and without LTx; harmonization of CF care throughout European countries and minimization of the onset of pulmonary gas exchange abnormalities using all available means remains of paramount importance.

PMID:36935771 | PMC:PMC10022450 | DOI:10.2147/TCRM.S391476

J Cyst Fibros. 2023 Mar 16:S1569-1993(23)00073-5. doi: 10.1016/j.jcf.2023.03.008. Online ahead of print.

ABSTRACT

BACKGROUND: Regular surveillance microbiology of sputum is used in cystic fibrosis (CF) to monitor for new pathogens and target treatments. A move to remote clinics has meant greater reliance on samples collected at home and posted back. The impact of delays and sample disruption caused by posting has not been systematically assessed but could have significant implications for CF microbiology.

METHODS: Sputum samples collected from adult CF patients were mixed, split, and either processed immediately or posted back to laboratory. Processing involved a further split into aliquots for culture-dependant and-independent microbiology (quantitative PCR [QPCR] and microbiota sequencing). We calculated retrieval by both approaches for five typical CF pathogens: Pseudomonas aeruginosa, Burkholderia cepacia complex, Achromobacter xylosoxidans, Staphylococcus aureus and Stenotrophomonas maltophilia.

RESULTS: 93 paired samples were collected from 73 CF patients. Median interval between sample posting and receipt was 5 days (range 1-10). For culture, overall concordance for posted and fresh samples was 86% across the five targeted pathogens (ranging from 57 to 100% for different organisms), with no bias towards either sample type. For QPCR, overall concordance was 62% (range 39-84%), again with no bias towards fresh or posted samples. There were no significant differences in culture or QPCR for samples with short (≤3days) versus extended (≥7days) postal delays. Posting had no significant impact on pathogen abundance nor on microbiota characteristics.

CONCLUSIONS: Posted sputum samples reliably reproduced culture-based and molecular microbiology of freshly collected samples, even after prolonged delays at ambient conditions. This supports use of posted samples during remote monitoring.

PMID:36934050 | DOI:10.1016/j.jcf.2023.03.008

An Pediatr (Engl Ed). 2023 Mar 15:S2341-2879(23)00057-1. doi: 10.1016/j.anpede.2023.02.015. Online ahead of print.

ABSTRACT

OBJECTIVES: Based on the European and American Cystic Fibrosis (CF) consensus recommendations, an increase in vitamin D (VD) supplementation in patients with CF and insufficient or defficient levels was proposed. The objective of our study was to determine the safety and efficacy of this new protocol.

MATERIAL AND METHODS: Multicentre nonrandomized uncontrolled experimental study. Patients with insufficient levels (<30 ng/mL) received increasing doses of VD (between 800 and 10 000 IU/day). Patients were followed up for 12 months, during which their vitamin and nutritional status, pulmonary function and calcium and phosphate metabolism were assessed.

STATISTICAL ANALYSIS: t test for paired data and multivariate logistic regression analysis.

RESULTS: Thirty patients aged 1-39 years (median, 9.1) completed the follow-up. Two patients were dropped from the study on account of 25-OH VD levels greater than 100 ng/mL at 3 months without clinical or laboratory signs of hypercalcaemia. At 12 months, we observed an increase of 7.6 ng/mL (95% CI, 4.6-10 ng/mL) in the mean 25-OH VD level and an improvement in vitamin status: 37% achieved levels of 30 ng/mL or greater, 50% levels between 20 and 30 ng/mL and 13% remained with levels of less than 20 ng/mL. We found no association between improved VD levels and pulmonary function.

CONCLUSIONS: The proposed protocol achieved an increase in serum VD levels and a decrease in the percentage of patients with VD insufficiency, although it was still far from reaching the percentages of sufficiency recommended for this entity.

PMID:36932016 | DOI:10.1016/j.anpede.2023.02.015

Respir Med. 2023 Mar 15:107217. doi: 10.1016/j.rmed.2023.107217. Online ahead of print.

ABSTRACT

Bronchiectasis (BE) is a chronic condition characterized by airway dilation as a consequence of a variety of pathogenic processes. It is often associated with persistent airway infection and an inflammatory response resulting in cough productive of purulent sputum, which has an adverse impact on quality of life. The prevalence of BE is increasing worldwide. Treatment guidelines exist for managing BE, but they are generally informed by a paucity of high-quality evidence. This review presents the findings of a scientific advisory board of experts held in the United States in November 2020. The main focus of the meeting was to identify unmet needs in BE and propose ways to identify research priorities for the management of BE, with a view to developing evidence-based treatment recommendations. Key issues identified include diagnosis, patient evaluation, promoting airway clearance and appropriate use of antimicrobials. Unmet needs include effective pharmacological agents to promote airway clearance and reduce inflammation, control of chronic infection, clinical endpoints to be used in the design of BE clinical trials, and more accurate classification of patients using phenotypes and endotypes to better guide treatment decisions and improve outcomes.

PMID:36931575 | DOI:10.1016/j.rmed.2023.107217

Cell Rep. 2023 Mar 16;42(3):112270. doi: 10.1016/j.celrep.2023.112270. Online ahead of print.

ABSTRACT

The cystic fibrosis (CF) respiratory tract harbors pathogenic bacteria that cause life-threatening chronic infections. Of these, Pseudomonas aeruginosa becomes increasingly dominant with age and is associated with worsening lung function and declining microbial diversity. We aimed to understand why P. aeruginosa dominates over other pathogens to cause worsening disease. Here, we show that P. aeruginosa responds to dynamic changes in iron concentration, often associated with viral infection and pulmonary exacerbations, to become more competitive via expression of the TseT toxic effector. However, this behavior can be therapeutically targeted using the iron chelator deferiprone to block TseT expression and competition. Overall, we find that iron concentration and TseT expression significantly correlate with microbial diversity in the respiratory tract of people with CF. These findings improve our understanding of how P. aeruginosa becomes increasingly dominant with age in people with CF and provide a therapeutically targetable pathway to help prevent this shift.

PMID:36930643 | DOI:10.1016/j.celrep.2023.112270

Pediatr Pulmonol. 2023 Mar 17. doi: 10.1002/ppul.26387. Online ahead of print.

ABSTRACT

Asthma is a common disease in childhood with a minority of affected children suffering from severe asthma. Patients with severe asthma require high dose inhaled glucocorticoids plus a second controller and/or systemic corticosteroids to be well-controlled or remain uncontrolled despite such treatment. Although only a small subset of children and adolescents falls in this category, the management of affected patients represents a major concern for pediatricians. Guidelines and recommendations have been designed to guide the management of this group of patients. Though the terms "recommendations" and "guidelines" are often used interchangeably, it should be noted that the first one should be used more narrowly to identify specific actions and the second one to broadly refer to the umbrella under which multiple recommendations for a specific condition are provided. Moreover, the availability of several and sometimes-conflicting documents on severe asthma management both in adult and pediatric age could generate confusion among health care professionals. The manuscript analyses seven papers addressing severe asthma, comparing any key aspects and differences. Finally, we tried to create a more practical document for physicians to simplify the interpretation of the several available documents on severe asthma management focusing the pediatric age.

PMID:36929867 | DOI:10.1002/ppul.26387

Pediatr Pulmonol. 2023 Mar 17. doi: 10.1002/ppul.26388. Online ahead of print.

ABSTRACT

BACKGROUND: The effects of elexacaftor-tezacaftor-ivacaftor (ETI) on body composition in people with CF (pwCF) are unknown.

METHODS: Dual-energy X-ray absorptiometry fat-free mass and fat mass adjusted for height (FMI) as well as oral glucose tolerance test derived measures of insulin secretion and sensitivity were compared before and after ETI initiation in eight pwCF.

RESULTS: Patients median age: 22 years interquartile range (IQR: 16-28), 87.5% male, median time on ETI:11 months. Weight z-score increased from -0.52 to 0.18 (p = 0.014); FMI increased from 4.12 to 6.29 (p = 0.014). Insulin secretion (C pep iAUC/Gluc iAUC) increased from 8.71 to 14.21 (p = 0.021), insulin resistance (HOMA2 IR) increased from 0.73 to 1.25 (p = 0.014) and insulin sensitivity decreased (Matsuda) 8.88 to 5.58 (p = 0.036).

CONCLUSIONS: ETI resulted in increased weight and fat mass. BMI and muscle mass did not change. Both insulin secretion and insulin resistance increased. Longer-term metabolic consequences of ETI need further investigation.

PMID:36929859 | DOI:10.1002/ppul.26388

Clin Respir J. 2023 Mar 16. doi: 10.1111/crj.13605. Online ahead of print.

ABSTRACT

INTRODUCTION: The pathogenesis of non-cystic fibrosis bronchiectasis has not been clearly clarified. This study aimed to investigate the expression of ciliary regulating protein forkhead box protein j1 (Foxj1) on airway epithelium in non-cystic fibrosis bronchiectasis and its association with airway cilia structure disorder and disease severity.

METHODS: Lung tissue sections excised from 47 patients with non-cystic fibrosis bronchiectasis were included between January 2018 and June 2021. Specimens from 26 subjects who underwent a lobectomy due to lung nodule were chosen as controls. Clinical information was collected, and pathologic analysis was performed to assess the epithelial structure and expression of ciliary regulating Foxj1.

RESULTS: Of the 47 patients with non-cystic fibrosis bronchiectasis, 25 were considered as mild, 12 were moderate whereas the remaining 10 cases were severe according to the bronchiectasis severity index score evaluation. Epithelial hyperplasia, hyperplasia of goblet cells and inflammatory cell infiltration were observed in non-cystic fibrosis bronchiectasis, compared with control subjects. Cilia length in non-cystic fibrosis bronchiectasis patients were shorter than that in the control group, (5.34 ± 0.89) μm versus (7.34 ± 0.71) μm, respectively (P = 0.002). The expression of Foxj1 was (2.69 ± 1.09) × 106 in non-cystic fibrosis bronchiectasis, compared with (6.67 ± 1.15) × 106 in the control group (P = 0.001). Moreover, patients with lower expression of Foxj1 showed shorter airway cilia and worse in disease severity.

CONCLUSION: Foxj1 declined in the airway epithelium of patients with non-cystic fibrosis bronchiectasis, positively correlated to cilia length and might imply worse disease severity.

PMID:36929635 | DOI:10.1111/crj.13605

J Exp Med. 2023 Jun 5;220(6):e20221086. doi: 10.1084/jem.20221086. Epub 2023 Mar 16.

ABSTRACT

Extracellular DNase DNASE1L3 maintains tolerance to self-DNA in humans and mice, whereas the role of its homolog DNASE1 remains controversial, and the overall function of secreted DNases in immunity is unclear. We report that deletion of murine DNASE1 neither caused autoreactivity in isolation nor exacerbated lupus-like disease in DNASE1L3-deficient mice. However, combined deficiency of DNASE1 and DNASE1L3 rendered mice susceptible to bloodstream infection with Staphylococcus aureus. DNASE1/DNASE1L3 double-deficient mice mounted a normal innate response to S. aureus and did not accumulate neutrophil extracellular traps (NETs). However, their kidneys manifested severe pathology, increased bacterial burden, and biofilm-like bacterial lesions that contained bacterial DNA and excluded neutrophils. Furthermore, systemic administration of recombinant DNASE1 protein during S. aureus infection rescued the mortality of DNase-deficient mice and ameliorated the disease in wild-type mice. Thus, DNASE1 and DNASE1L3 jointly facilitate the control of bacterial infection by digesting extracellular microbial DNA in biofilms, suggesting the original evolutionary function of secreted DNases as antimicrobial agents.

PMID:36928522 | DOI:10.1084/jem.20221086

Respir Res. 2023 Mar 16;24(1):83. doi: 10.1186/s12931-023-02381-x.

ABSTRACT

BACKGROUND: The respiratory tract is protected from inhaled particles and microbes by mucociliary clearance, mediated by the mucus and the cilia creating a flow to move the mucus cephalad. Submucosal glands secrete linear MUC5B mucin polymers and because they pass through the gland duct before reaching the airway surface, bundled strands of 1000-5000 parallel molecules exit the glands. In contrast, the surface goblet cells secrete both MUC5AC and MUC5B.

METHODS: We used mass-spectrometry based proteomic analysis of unstimulated and carbachol stimulated newborn wild-type (WT) and cystic fibrosis transmembrane conductance regulator (CFTR) null (CF) piglet airways to study proteins in the airway surface liquid and mucus, to investigate if levels of MUC5AC and MUC5B were affected by carbachol stimulation and whether the proteins clustered according to function.

RESULTS: Proteins in the first four extracted fractions clustered together and the fifth fraction contained the mucus cluster, mucins and other proteins known to associate with mucins, whereas the traditional airway surface liquid proteins clustered to fraction 1-4 and were absent from the mucus fraction. Carbachol stimulation resulted in increased MUC5AC and MUC5B.

CONCLUSIONS: These results indicate a distinct separation between proteins in the washable surface liquid and the mucus fraction. In fractions 1-4 from newborn CF piglets an additional cluster containing acute phase proteins was observed, suggesting an early inflammatory response in CF piglets. Alternatively, increased levels of these proteins could indicate altered lung development in the CF piglets. This observation suggests that CF airway disease is present at birth and thus, treatment should commence directly after diagnosis.

PMID:36927357 | DOI:10.1186/s12931-023-02381-x