Cancer Burden Is Controlled by Mural Cell-ß3-Integrin Regulated Crosstalk with Tumor Cells.

Enhanced blood vessel (BV) formation is thought to drive tumor growth through elevated nutrient delivery. However, this observation has overlooked potential roles for mural cells in directly affecting tumor growth independent of BV function. Here we provide clinical data correlating high percentages of mural-ß3-integrin-negative tumor BVs with increased tumor sizes but no effect on BV numbers. Mural-ß3-integrin loss also enhances tumor growth in implanted and autochthonous mouse tumor models with no detectable effects on BV numbers or function. At a molecular level, mural-cell ß3-integrin loss enhances signaling via FAK-p-HGFR-p-Akt-p-p65, driving CXCL1, CCL2, and TIMP-1 production. In particular, mural-cell-derived CCL2 stimulates tumor cell MEK1-ERK1/2-ROCK2-dependent signaling and enhances tumor cell survival and tumor growth. Overall, our data indicate that mural cells can control tumor growth via paracrine signals regulated by ß3-integrin, providing a previously unrecognized mechanism of cancer growth control.

Regional Activation of Myosin II in Cancer Cells Drives Tumor Progression via a Secretory Cross-Talk with the Immune Microenvironment.

ROCK-Myosin II drives fast rounded-amoeboid migration in cancer cells during metastatic dissemination. Analysis of human melanoma biopsies revealed that amoeboid melanoma cells with high Myosin II activity are predominant in the invasive fronts of primary tumors in proximity to CD206+CD163+ tumor-associated macrophages and vessels. Proteomic analysis shows that ROCK-Myosin II activity in amoeboid cancer cells controls an immunomodulatory secretome, enabling the recruitment of monocytes and their differentiation into tumor-promoting macrophages. Both amoeboid cancer cells and their associated macrophages support an abnormal vasculature, which ultimately facilitates tumor progression. Mechanistically, amoeboid cancer cells perpetuate their behavior via ROCK-Myosin II-driven IL-1α secretion and NF-κB activation. Using an array of tumor models, we show that high Myosin II activity in tumor cells reprograms the innate immune microenvironment to support tumor growth. We describe an unexpected role for Myosin II dynamics in cancer cells controlling myeloid function via secreted factors.

The nuclear receptor LXRα controls the functional specialization of splenic macrophages.

Macrophages are professional phagocytic cells that orchestrate innate immune responses and have considerable phenotypic diversity at different anatomical locations. However, the mechanisms that control the heterogeneity of tissue macrophages are not well characterized. Here we found that the nuclear receptor LXRα was essential for the differentiation of macrophages in the marginal zone (MZ) of the spleen. LXR-deficient mice were defective in the generation of MZ and metallophilic macrophages, which resulted in abnormal responses to blood-borne antigens. Myeloid-specific expression of LXRα or adoptive transfer of wild-type monocytes restored the MZ microenvironment in LXRα-deficient mice. Our results demonstrate that signaling via LXRα in myeloid cells is crucial for the generation of splenic MZ macrophages and identify an unprecedented role for a nuclear receptor in the generation of specialized macrophage subsets.

Endogenous LXR signaling controls pulmonary surfactant homeostasis and prevents lung inflammation.

Lung type 2 pneumocytes (T2Ps) and alveolar macrophages (AMs) play crucial roles in the synthesis, recycling and catabolism of surfactant material, a lipid/protein fluid essential for respiratory function. The liver X receptors (LXR), LXRα and LXRß, are transcription factors important for lipid metabolism and inflammation. While LXR activation exerts anti-inflammatory actions in lung injury caused by lipopolysaccharide (LPS) and other inflammatory stimuli, the full extent of the endogenous LXR transcriptional activity in pulmonary homeostasis is incompletely understood. Here, using mice lacking LXRα and LXRß as experimental models, we describe how the loss of LXRs causes pulmonary lipidosis, pulmonary congestion, fibrosis and chronic inflammation due to defective de novo synthesis and recycling of surfactant material by T2Ps and defective phagocytosis and degradation of excess surfactant by AMs. LXR-deficient T2Ps display aberrant lamellar bodies and decreased expression of genes encoding for surfactant proteins and enzymes involved in cholesterol, fatty acids, and phospholipid metabolism. Moreover, LXR-deficient lungs accumulate foamy AMs with aberrant expression of cholesterol and phospholipid metabolism genes. Using a house dust mite aeroallergen-induced mouse model of asthma, we show that LXR-deficient mice exhibit a more pronounced airway reactivity to a methacholine challenge and greater pulmonary infiltration, indicating an altered physiology of LXR-deficient lungs. Moreover, pretreatment with LXR agonists ameliorated the airway reactivity in WT mice sensitized to house dust mite extracts, confirming that LXR plays an important role in lung physiology and suggesting that agonist pharmacology could be used to treat inflammatory lung diseases.

Removal of heavy metals from mine tailings by in-situ bioleaching coupled to electrokinetics.

This work utilizes a combined biological-electrochemical technique for the in-situ removal of metals from polluted mine tailings. As the main novelty point it is proposed to use electrokinetics (EK) for the in-situ activation of a bioleaching mechanism into the tailings, in order to promote biological dissolution of metal sulphides (Step 1), and for the subsequent removal of leached metals by EK transport out of the tailings (Step 2). Mine tailings were collected from an abandoned Pb/Zn mine located in central-southern Spain. EK-bioleaching experiments were performed under batch mode using a lab scale EK cell. A mixed microbial culture of autochthonous acidophilic bacteria grown from the tailings was used. Direct current with polarity reversal vs alternate current was evaluated in Step 1. In turn, different biological strategies were used: biostimulation, bioaugmentation and the abiotic reference test (EK alone). It was observed that bioleaching activation was very low during Step 1, because it was difficult to maintain acidic pH in the whole soil, but then it worked correctly during Step 2. It was confirmed that microorganisms successfully contributed to the in-situ solubilization of the metal sulphides as final metal removal rates were improved compared to the conventional abiotic EK (best increases of around 40% for Cu, 162% for Pb, 18% for Zn, 13% for Mn, 40% for Ni and 15% for Cr). Alternate current seemed to be the best option. The tailings concentrations of Fe, Al, Cu, Mn, Ni and Pb after treatment comply with regulations, but Pb, Cd and Zn concentrations exceed the maximum values. From the data obtained in this work it has been observed that EK-bioleaching could be feasible, but some upgrades and future work must be done in order to optimize experimental conditions, especially the control of soil pH in acidic values.

Predictive factors for flea occurrence in red foxes (Vulpes vulpes) from semi-arid Mediterranean environments.

The role of red fox as host for a wide range of parasites, particularly fleas and other arthropods causing vector-borne diseases, in combination with its capability to adapt to anthropized environments, makes this wild canid an epidemiologically remarkable species at the wildlife-domestic-human interface, especially in the present time of rise of emerging and re-emerging diseases. This study evaluated the prevalence and parasite intensity of fleas in 88 foxes from Murcia Region (Southeastern Spain) and determined the geographic distribution of areas with the highest potential risk of flea presence. Pulex irritans, Ctenocephalides felis, Spilopsyllus cuniculi and Nosopsyllus fasciatus were identified. The overall prevalence was 76.13%. This is the first time that N. fasciatus has been reported in foxes from Murcia Region. The predictive model established a certain pattern to determine the areas with the highest risk of acquiring fleas. Positive correlation of daily potential evapotranspiration (ET0 ) in winter and the opposite effect occurring for ET0 in summer were obtained, as well as positive correlations for mean daily temperature (Tmean ) in summer and mean precipitation (Pmean ) in winter and summer. The model was also found positively correlated in the forest habitat ecotone areas and the anthropized areas.

Complete mitochondrial genome of Metathelazia capsulata (Pneumospiruridae) and comparison with other Spiruromorpha species.

Metathelazia capsulata (family Pneumospiruridae) is a lungworm parasitizing the bronchi and bronchioles, described in four species of wild carnivores. Very little molecular data are available on this nematode and none on other species of the Pneumospiruridae family. In this work, we describe for the first time the complete mitogenome (mitochondrial genome) of M. capsulata, being the first described of the family Pneumospiruridae. The mitogenome of M. capsulata has 13,659 bp in length, an A + T content of 79.2%. The mitogenome included 12 protein-coding genes (PCGs) (lacking the atp8 gene), 22 tRNA genes, 2 rRNA genes (all the genes are coded by the heavy strand), and an AT-rich region. The PCGs varied in size (232 bp-1645 bp). Only the tRNA-Trp has the standard cloverleaf secondary structure, while the other 21 do not. The AT-rich region, with a 90.5% A + T content and a length of 389 bp, is located between the cox3 and tRNA-Ala genes. Comparison with the mitogenomes of 29 species of Spiruromorpha infraorder, belonging to different families, demonstrates that M. capsulata mitogenome shared the common characteristics of most of them. The phylogeny constructions yielded phylogenies that were in agreement with the obtained previously by using sequences and gene order data of mitogenomes.

Analysis of different gamification-based teaching resources for physiotherapy students: a comparative study.

BACKGROUND: For health professionals, gamification is a new teaching method that has achieved an important role in recent years, with excellent results in learning and knowledge acquisition. Thus, the objective of this study was to analyze the gaming experience through different gamification resources in the classroom with physiotherapy students. METHODS: A comparative study on gamification-based teaching resources was carried out during the first semester of the 2021-2022 academic year. A total of 33 physiotherapy students participated in this study. After the theoretical topics were taught, the participants were invited to participate in different gamification resources such as Kahoot!, Physiotherapy Party and Escape Room. The gaming experience with the different gamification resources was measured with the GAMEX scale. RESULTS: The Physiotherapy Party showed a higher score in relation to the enjoyment dimension compared to the Kahoot! and Escape Room (p = 0.004). The Escape Room presented higher scores in absorption, creative thinking, activation and dominance compared to Kahoot! and Physiotherapy Party (p < 0.005). CONCLUSIONS: Gamification resources promote enjoyment and creativity in the students in the classroom. The use of new teaching methods based on gamification, such as Escape Room as Physiotherapy Party should be considered as first choice in the use of gamification resources due to the benefits they bring to students.

Assessing Dysferlinopathy Patients Over Three Years With a New Motor Scale.

OBJECTIVE: Dysferlinopathy is a muscular dystrophy with a highly variable clinical presentation and currently unpredictable progression. This variability and unpredictability presents difficulties for prognostication and clinical trial design. The Jain Clinical Outcomes Study of Dysferlinopathy aims to establish the validity of the North Star Assessment for Limb Girdle Type Muscular Dystrophies (NSAD) scale and identify factors that influence the rate of disease progression using NSAD. METHODS: We collected a longitudinal series of functional assessments from 187 patients with dysferlinopathy over 3 years. Rasch analysis was used to develop the NSAD, a motor performance scale suitable for ambulant and nonambulant patients. Generalized estimating equations were used to evaluate the impact of patient factors on outcome trajectories. RESULTS: The NSAD detected significant change in clinical progression over 1 year. The steepest functional decline occurred during the first 10 years after symptom onset, with more rapid decline noted in patients who developed symptoms at a younger age (p = 0.04). The most rapidly deteriorating group over the study was patients 3 to 8 years post symptom onset at baseline. INTERPRETATION: The NSAD is the first validated limb girdle specific scale of motor performance, suitable for use in clinical practice and clinical trials. Longitudinal analysis showed it may be possible to identify patient factors associated with greater functional decline both across the disease course and in the short-term for clinical trial preparation. Through further work and validation in this cohort, we anticipate that a disease model incorporating functional performance will allow for more accurate prognosis for patients with dysferlinopathy. ANN NEUROL 2021;89:967-978.

A preclinical pipeline to evaluate migrastatics as therapeutic agents in metastatic melanoma.

BACKGROUND: Metastasis is a hallmark of cancer and responsible for most cancer deaths. Migrastatics were defined as drugs interfering with all modes of cancer cell invasion and thus cancers' ability to metastasise. First anti-metastatic treatments have recently been approved. METHODS: We used bioinformatic analyses of publicly available melanoma databases. Experimentally, we performed in vitro target validation (including 2.5D cell morphology analysis and mass spectrometric analysis of RhoA binding partners), developed a new traceable spontaneously metastasising murine melanoma model for in vivo validation, and employed histology (haematoxylin/eosin and phospho-myosin II staining) to confirm drug action in harvested tumour tissues. RESULTS: Unbiased and targeted bioinformatic analyses identified the Rho kinase (ROCK)-myosin II pathway and its various components as potentially relevant targets in melanoma. In vitro validation demonstrated redundancy of several RhoGEFs upstream of RhoA and confirmed ROCK as a druggable target downstream of RhoA. The anti-metastatic effects of two ROCK inhibitors were demonstrated through in vivo melanoma metastasis tracking and inhibitor effects also confirmed ex vivo by digital pathology. CONCLUSIONS: We proposed a migrastatic drug development pipeline. As part of the pipeline, we provide a new traceable spontaneous melanoma metastasis model for in vivo quantification of metastasis and anti-metastatic effects by non-invasive imaging.

General Spanish population normative data analysis for the EORTC QLQ-C30 by sex, age, and health condition.

PURPOSE: General population normative data for the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30 questionnaire facilitates interpretation of data assessed from cancer patients. This study aims to present normative data of the general Spanish population. METHODS/PATIENTS: Data were obtained from a prior larger study collecting EORTC QLQ-C30 norm data across 15 countries. Data were stratified by sex and age groups (18-39, 40-49, 50-59, 60-69 and > 70 years). Sex and age distribution were weighted according to population distribution statistics. Sex- and age-specific normative values were analysed separately, as were participants with versus those without health conditions. Multiple linear regression was used to estimate the association of each of the EORTC QLQ-C30 scales with the determinants age, sex, sex-by-age interaction term, and health condition. RESULTS: In total, 1,165 Spanish individuals participated in the study. Differences were found by sex and age. The largest sex-related differences were seen in fatigue, emotional functioning, and global QOL (Quality of Life), favouring men. The largest age differences were seen in emotional functioning, insomnia, and pain, with middle-aged groups having the worst scores. Those > 60 years old scored better than those < 60 years old on all scales except for physical functioning. Participants with no health conditions scored better in all QLQ-C30 domains. CONCLUSIONS: The present study highlights differences in HRQOL between specific sex/age strata and especially between people with and without a health condition in the general Spanish population. These factors must be considered when comparing general population HRQOL data with that of cancer patients.

Candidemia Diagnosis With T2 Nuclear Magnetic Resonance in a PICU: A New Approach.

OBJECTIVES: Early diagnosis of invasive Candida infections is a challenge for pediatricians, intensivists, and microbiologists. To fill this gap, a new nanodiagnostic method has been developed using manual application of T2 nuclear magnetic resonance to detect Candida species. The aim of this study was to evaluate, prospectively, the usefulness as a tool diagnosis of the T2Candida panel in pediatric patients admitted at the PICU compared with blood culture. DESIGN: This is a prospective, observational, and unicentric study to compare T2Candida results with simultaneous blood cultures for candidemia diagnose. SETTING: This study was carried out in a 1,300-bed tertiary care hospital with a 16-bed medical-surgical PICU. PATIENTS: Sixty-three patients from 0 to 17 years old were enrolled in this study, including those undergoing solid organ transplantation (kidney, liver, pulmonary, multivisceral, intestinal, and heart) and hematopoietic stem cell transplantation. MEASUREMENTS AND MAIN RESULTS: Seven patients were positive by the T2Candida test. Only two of them had the simultaneous positive blood culture. T2Candida yielded more positive results than blood cultures. CONCLUSIONS: T2Candida might be useful for the diagnosis of candidemia in PICUs. The prevalence of candidemia might be underestimated in this pediatric population. The use of this diagnostic tool in these units may help clinicians to start adequate and timely antifungal treatments.

Staphylococcal toxic shock syndrome in a child with interleukin-17 inhibitor treatment for psoriasis.

A 6-year-old girl presented with fever, skin rash, anuria, and conjunctivitis that rapidly progressed to toxic shock syndrome. Following hospital discharge, she developed a staphylococcal abscess on the lower extremity. She had recently received the first two doses of the interleukin-17 (IL-17) inhibitor secukinumab for resistant plaque psoriasis. IL-17 is known to be essential in host defense against Staphylococcus aureus. To our knowledge, this is the first reported case of staphylococcal toxic shock syndrome (STSS) associated with an IL-17 inhibitor.

Study of the effect of anti-rhGAA antibodies at low and intermediate titers in late onset Pompe patients treated with ERT.

Late onset Pompe disease (LOPD) is a genetic disorder characterized by slowly progressive skeletal and respiratory muscle weakness. Symptomatic patients are treated with enzyme replacement therapy (ERT) with alglucosidase alpha (rhGAA). Although most of ERT treated patients develop antibodies against rhGAA, their influence on clinical progression is not completely known. We studied the impact of anti-rhGAA antibodies on clinical progression of 25 ERT treated patients. We evaluated patients at visit 0 and, after 1 year, at visit 1. We performed several muscle function tests, conventional spirometry and quantitative muscle MRI (qMRI) using 3-point Dixon analysis of thigh muscles at both visits. We also obtained serum samples at both visits and anti-rhGAA antibodies were quantified using ELISA. Antibody titers higher than 1:200 were identified in 18 patients (72%) of our cohort. Seven patients (28%) did not develop antibodies (0 to <1:200), 17 patients (68%) developed low to intermediate titers (1:200 to <1:31,200) and 1 patient (4%) developed high titers (>1:31,200). We analyzed the effect of low and intermediate antibody titers in clinical and radiological progression. There were no differences between the results of muscle function tests, spirometry or fat fraction analyzed using qMRI between patients with and without antibodies groups at baseline. Moreover, antibody titers did not influence muscle function test, spirometry results or qMRI results at year 1 visit. Most of the LOPD patients developed antibodies against ERT that persisted over time at low or intermediate levels. However, antibodies at these low and intermediate titers might not influence clinical response to the drug.

Circulating Tumor Cells in Patients Undergoing Resection of Colorectal Cancer Liver Metastases. Clinical Utility for Long-Term Outcome: A Prospective Trial.

BACKGROUND: Patients with resected colorectal cancer liver metastases display heterogeneous clinical behavior. The identification of new prognostic factors would help in making more accurate decisions. OBJECTIVE: The aim of this study was to evaluate the survival impact of circulating tumor cells (CTCs) in this setting. METHODS: We conducted a prospective study of patients with resected liver metastases of colorectal cancer. Patients were included in the study from February 2009 to January 2013. The CellSearch System™ was employed for the detection of pre- and postsurgery CTCs. A positive test was defined as two or more CTCs/7.5 mL of blood. Recurrence rate, disease-free survival, and overall survival were calculated, and univariate and multivariate analyses were performed. RESULTS: Forty-four patients were included in our study. After a median follow-up of 60 months (range 28-74), 32 patients experienced recurrence (72.7%). The CTCs number was determined and the test was positive in 8 patients (18.6%) before surgery and 13 patients (29.5%) after surgery. The postoperative detection of CTCs was not related to any clinical outcome; however, the preoperative detection of CTCs was significantly related to behavior. All patients in the preoperative CTC-positive group relapsed, versus 65% in the CTC-negative group (p = 0.051). Disease-free survival was 19 months in the preoperative CTC-negative group versus 7 months in the CTC-positive group (p = 0.01). Additionally, overall survival was 69 months in the preoperative CTC-negative group versus 17 months in the CTC-positive group (p = 0.004). Preoperative CTC count remained significant in multivariate analysis. CONCLUSIONS: In this cohort of colorectal cancer liver metastases patients, the presence of two or more preoperative CTCs was associated with disease progression and poor survival despite complete resection.

An efficient method for eccrine gland isolation from human scalp.

We describe a simple and efficient method to isolate eccrine sweat glands from the human scalp. This method is inspired by the hair graft harvesting method used in hair transplantation. Based on the recently described anatomical relationship between the scalp hair follicle and the eccrine gland, we have found that scalp follicular unit grafts are an excellent eccrine gland isolation source, especially for the coiled component. In order to make the gland visible for stereoscopic microdissection, the follicular units need to be previously stained with a vital dye like methylene blue or neutral red. The simplicity and efficiency of this isolation method should encourage further research into human eccrine sweat gland function which has always been hindered by the difficulty of gland isolation.

Insulinaemia and insulin resistance in Caucasian general paediatric population aged 2 to 10 years: Associated risk factors.

BACKGROUND: The aim of this study is to determine values of insulinaemia, homeostasis model assessment (HOMA) index and quantitative insulin sensitivity check index (QUICKI) among a population of prepubertal Caucasian children, to analyse factors associated with insulin resistance (IR), and to study its association with cardiovascular risk factors. MATERIALS AND METHODS: Population-based study conducted on a randomly selected sample of prepubescent Caucasian subjects aged 2.00 to 9.99 years old. Anthropometric measurements, blood pressure, and fasting blood samples were obtained, including fasting glucose, triglycerides, High Density Lipoprotein (HDL)-cholesterol, and insulin. In addition, QUICKI and HOMA indices were calculated. Generalised additive models for location, scale and shape (GAMLSS) was used to calculate centiles curves and multivariate logistic regression analysis to assess factors associated with IR. RESULTS: A total of 654 subjects were included. Mean values obtained for insulinaemia, HOMA index, and QUICKI were 3.74 µIU/mL, 0.73, and 0.44, respectively, in the overall population and 3.32 µIU/mL, 0.64 and 0.46, respectively, in normal weight subjects. The main factor associated with IR was abdominal obesity (odds ratio [OR] 3.38 [95% CI 1.44-7.94] in the subgroup aged 2.00-5.99 years and OR 9.14 [3.42-24.41] for those aged 6.00-9.99 years). An increased risk of hyperglycaemia (P = 0.043), hypertriglyceridaemia (P < .001), and HDL < p10 (P = 0.021) was described among children aged 2.00 to 5.99 years with IR, and among those aged 6.00 to 9.99 years, IR was associated with an increased risk of hypertriglyceridaemia (P < .001). CONCLUSION: Abdominal obesity was the main factor associated with IR. Metabolic changes associated with IR seem to be present from early stages of life, which highlights the importance of the prevention, early diagnosis and treatment of obesity.

EPCR-dependent PAR2 activation by the blood coagulation initiation complex regulates LPS-triggered interferon responses in mice.

Infection and inflammation are invariably associated with activation of the blood coagulation mechanism, secondary to the inflammation-induced expression of the coagulation initiator tissue factor (TF) on innate immune cells. By investigating the role of cell-surface receptors for coagulation factors in mouse endotoxemia, we found that the protein C receptor (ProcR; EPCR) was required for the normal in vivo and in vitro induction of lipopolysaccharide (LPS)-regulated gene expression. In cultured bone marrow-derived myeloid cells and in monocytic RAW264.7 cells, the LPS-induced expression of functionally active TF, assembly of the ternary TF-VIIa-Xa initiation complex of blood coagulation, and the EPCR-dependent activation of protease-activated receptor 2 (PAR2) by the ternary TF-VIIa-Xa complex were required for the normal LPS induction of messenger RNAs encoding the TLR3/4 signaling adaptor protein Pellino-1 and the transcription factor interferon regulatory factor 8. In response to in vivo challenge with LPS, mice lacking EPCR or PAR2 failed to fully initiate an interferon-regulated gene expression program that included the Irf8 target genes Lif, Iigp1, Gbp2, Gbp3, and Gbp6. The inflammation-induced expression of TF and crosstalk with EPCR, PAR2, and TLR4 therefore appear necessary for the normal evolution of interferon-regulated host responses.

Coagulation factor V mediates inhibition of tissue factor signaling by activated protein C in mice.

The key effector molecule of the natural protein C pathway, activated protein C (aPC), exerts pleiotropic effects on coagulation, fibrinolysis, and inflammation. Coagulation-independent cell signaling by aPC appears to be the predominant mechanism underlying its highly reproducible therapeutic efficacy in most animal models of injury and infection. In this study, using a mouse model of Staphylococcus aureus sepsis, we demonstrate marked disease stage-specific effects of the anticoagulant and cell signaling functions of aPC. aPC resistance of factor (f)V due to the R506Q Leiden mutation protected against detrimental anticoagulant effects of aPC therapy but also abrogated the anti-inflammatory and mortality-reducing effects of the signaling-selective 5A-aPC variant that has minimal anticoagulant function. We found that procofactor V (cleaved by aPC at R506) and protein S were necessary cofactors for the aPC-mediated inhibition of inflammatory tissue-factor signaling. The anti-inflammatory cofactor function of fV involved the same structural features that govern its cofactor function for the anticoagulant effects of aPC, yet its anti-inflammatory activities did not involve proteolysis of activated coagulation factors Va and VIIIa. These findings reveal a novel biological function and mechanism of the protein C pathway in which protein S and the aPC-cleaved form of fV are cofactors for anti-inflammatory cell signaling by aPC in the context of endotoxemia and infection.

ABCG1 is required for pulmonary B-1 B cell and natural antibody homeostasis.

Many metabolic diseases, including atherosclerosis, type 2 diabetes, pulmonary alveolar proteinosis, and obesity, have a chronic inflammatory component involving both innate and adaptive immunity. Mice lacking the ATP-binding cassette transporter G1 (ABCG1) develop chronic inflammation in the lungs, which is associated with the lipid accumulation (cholesterol, cholesterol ester, and phospholipid) and cholesterol crystal deposition that are characteristic of atherosclerotic lesions and pulmonary alveolar proteinosis. In this article, we demonstrate that specific lipids, likely oxidized phospholipids and/or sterols, elicit a lung-specific immune response in Abcg1(-/-) mice. Loss of ABCG1 results in increased levels of specific oxysterols, phosphatidylcholines, and oxidized phospholipids, including 1-palmitoyl-2-(5'-oxovaleroyl)-sn-glycero-3-phosphocholine, in the lungs. Further, we identify a niche-specific increase in natural Ab (NAb)-secreting B-1 B cells in response to this lipid accumulation that is paralleled by increased titers of IgM, IgA, and IgG against oxidation-specific epitopes, such as those on oxidized low-density lipoprotein and malondialdehyde-modified low-density lipoprotein. Finally, we identify a cytokine/chemokine signature that is reflective of increased B cell activation, Ab secretion, and homing. Collectively, these data demonstrate that the accumulation of lipids in Abcg1(-/-) mice induces the specific expansion and localization of B-1 B cells, which secrete NAbs that may help to protect against the development of atherosclerosis. Indeed, despite chronic lipid accumulation and inflammation, hyperlipidemic mice lacking ABCG1 develop smaller atherosclerotic lesions compared with controls. These data also suggest that Abcg1(-/-) mice may represent a new model in which to study the protective functions of B-1 B cells/NAbs and suggest novel targets for pharmacologic intervention and treatment of disease.