Cytokine-Mediated Degradation of the Transcription Factor ERG Impacts the Pulmonary Vascular Response to Systemic Inflammatory Challenge.

BACKGROUND: During infectious diseases, proinflammatory cytokines transiently destabilize interactions between adjacent vascular endothelial cells (ECs) to facilitate the passage of immune molecules and cells into tissues. However, in the lung, the resulting vascular hyperpermeability can lead to organ dysfunction. Previous work identified the transcription factor ERG (erythroblast transformation-specific-related gene) as a master regulator of endothelial homeostasis. Here we investigate whether the sensitivity of pulmonary blood vessels to cytokine-induced destabilization is due to organotypic mechanisms affecting the ability of endothelial ERG to protect lung ECs from inflammatory injury. METHODS: Cytokine-dependent ubiquitination and proteasomal degradation of ERG were analyzed in cultured HUVECs (human umbilical vein ECs). Systemic administration of TNFα (tumor necrosis factor alpha) or the bacterial cell wall component lipopolysaccharide was used to cause a widespread inflammatory challenge in mice; ERG protein levels were assessed by immunoprecipitation, immunoblot, and immunofluorescence. Murine Erg deletion was genetically induced in ECs (Ergfl/fl;Cdh5[PAC]-CreERT2), and multiple organs were analyzed by histology, immunostaining, and electron microscopy. RESULTS: In vitro, TNFα promoted the ubiquitination and degradation of ERG in HUVECs, which was blocked by the proteasomal inhibitor MG132. In vivo, systemic administration of TNFα or lipopolysaccharide resulted in a rapid and substantial degradation of ERG within lung ECs but not ECs of the retina, heart, liver, or kidney. Pulmonary ERG was also downregulated in a murine model of influenza infection. Ergfl/fl;Cdh5(PAC)-CreERT2 mice spontaneously recapitulated aspects of inflammatory challenges, including lung-predominant vascular hyperpermeability, immune cell recruitment, and fibrosis. These phenotypes were associated with a lung-specific decrease in the expression of Tek-a gene target of ERG previously implicated in maintaining pulmonary vascular stability during inflammation. CONCLUSIONS: Collectively, our data highlight a unique role for ERG in pulmonary vascular function. We propose that cytokine-induced ERG degradation and subsequent transcriptional changes in lung ECs play critical roles in the destabilization of pulmonary blood vessels during infectious diseases.

Acute Pericarditis: Rapid Evidence Review.

Acute pericarditis is defined as inflammation of the pericardium and occurs in approximately 4.4% of patients who present to the emergency department for nonischemic chest pain, with a higher prevalence in men. Although there are numerous etiologies of pericarditis, most episodes are idiopathic and the cause is presumed to be viral. Diagnosis of pericarditis requires at least two of the following criteria: new or worsening pericardial effusion, characteristic pleuritic chest pain, pericardial friction rub, or electrocardiographic changes, including new, widespread ST elevations or PR depressions. Pericardial friction rubs are highly specific but transient, and they have been reported in 18% to 84% of patients with acute pericarditis. Classic electrocardiographic findings include PR-segment depressions; diffuse, concave, upward ST-segment elevations without reciprocal changes; and T-wave inversions. Transthoracic echocardiography should be performed in all patients with acute pericarditis to characterize the size of effusions and evaluate for complications. Nonsteroidal anti-inflammatory drugs are the first-line treatment option. Glucocorticoids should be reserved for patients with contraindications to first-line therapy and those who are pregnant beyond 20 weeks' gestation or have other systemic inflammatory conditions. Colchicine should be used in combination with first- or second-line treatments to reduce the risk of recurrence. Patients with a higher risk of complications should be admitted to the hospital for further workup and treatment.

Collection and curation of prokaryotic genome assemblies from type strains at NCBI.

The public sequence databases are entrusted with the dual responsibility of providing an accessible archive to all submitters and supporting data reliability and its re-use to all users. Genomes from type materials can act as an unambiguous reference for a taxonomic name and play an important role in comparative genomics, especially for taxon verification or reclassification. The National Center for Biotechnology Information (NCBI) collects and curates information on prokaryotic type strains and genomes from type strains. The average nucleotide identity (ANI)-based quality control processes introduced at NCBI to verify the genomes from type strains and improve related sequence records are detailed here. Using the curated genomes from type strains as reference, the taxonomy of over 1.1 million GenBank genomes were verified and the taxonomy of over 7000 new submissions before acceptance to GenBank and over 1800 existing genomes in GenBank were reclassified.

Hip Fractures: Diagnosis and Management.

Hip fractures are common causes of disability, with mortality rates reaching 30% at one year. Nonmodifiable risk factors include lower socioeconomic status, older age, female sex, prior fracture, metabolic bone disease, and bony malignancy. Modifiable risk factors include low body mass index, having osteoporosis, increased fall risk, medications that increase fall risk or decrease bone mineral density, and substance use. Hip fractures present with anterior groin pain, inability to bear weight, or a shortened, abducted, externally rotated limb. Plain radiography is usually sufficient for diagnosis, but magnetic resonance imaging should be obtained if suspicion of fracture persists despite normal radiography. Operative management within 24 to 48 hours of the fracture optimizes outcomes. Fractures are usually managed by surgery, with the approach based on fracture type and location; spinal or general anesthesia can be used. Nonsurgical management can be considered for patients who are not good surgical candidates. Pre- and postoperative antistaphylococcal antibiotics are given to prevent joint infection. Medications for venous thromboembolism prophylaxis are also recommended. Physicians should be alert for the presence of delirium, which is a common postoperative complication. Early postoperative mobilization, followed by rehabilitation, improves outcomes. Subsequent care focuses on prevention, with increased physical activity, home safety assessments, and minimizing polypharmacy. Two less common hip fractures can also occur: femoral neck stress fractures and insufficiency fractures. Femoral neck stress fractures typically occur in dancers 20 to 30 years of age, endurance athletes, and military service members, often because of training overload. Insufficiency fractures due to compromised bone strength occur without trauma in postmenopausal women. If not recognized and treated, these fractures can progress to complete and displaced fractures with high rates of nonunion and avascular necrosis.

Rodent mnemonic similarity task performance requires the prefrontal cortex.

Mnemonic similarity task performance, in which a known target stimulus must be distinguished from similar lures, is supported by the hippocampus and perirhinal cortex. Impairments on this task are known to manifest with advancing age. Interestingly, disrupting hippocampal activity leads to mnemonic discrimination impairments when lures are novel, but not when they are familiar. This observation suggests that other brain structures support discrimination abilities as stimuli are learned. The prefrontal cortex (PFC) is critical for retrieval of remote events and executive functions, such as working memory, and is also particularly vulnerable to dysfunction in aging. Importantly, the medial PFC is reciprocally connected to the perirhinal cortex and neuron firing in this region coordinates communication between lateral entorhinal and perirhinal cortices to presumably modulate hippocampal activity. This anatomical organization and function of the medial PFC suggests that it contributes to mnemonic discrimination; however, this notion has not been empirically tested. In the current study, rats were trained on a LEGO object-based mnemonic similarity task adapted for rodents, and surgically implanted with guide cannulae targeting prelimbic and infralimbic regions of the medial PFC. Prior to mnemonic discrimination tests, rats received PFC infusions of the GABAA agonist muscimol. Analyses of expression of the neuronal activity-dependent immediate-early gene Arc in medial PFC and adjacent cortical regions confirmed muscimol infusions led to neuronal inactivation in the infralimbic and prelimbic cortices. Moreover, muscimol infusions in PFC impaired mnemonic discrimination performance relative to the vehicle control across all testing blocks when lures shared 50-90% feature overlap with the target. Thus, in contrast hippocampal infusions, PFC inactivation impaired target-lure discrimination regardless of the novelty or familiarity of the lures. These findings indicate the PFC plays a critical role in mnemonic similarity task performance, but the time course of PFC involvement is dissociable from that of the hippocampus.

Development of a pharmacy 'patient prioritization tool' for use in a Tertiary Paediatric Hospital.

WHAT IS KNOWN AND OBJECTIVE: Pharmacists play an integral role in paediatric patient care by ensuring the safe and optimal use of medications. There are increasing demands on pharmacists' time and challenges to meet them within allocated resources, and therefore, it is important to ensure that resources are used efficiently. Patient prioritization tools for clinical pharmacists have been proposed via many studies, but are generally adult-based and/or have not been validated to confirm their effectiveness. The aim of this study was to create, pilot and validate a patient prioritization tool to be used by pharmacists providing clinical pharmacy services to paediatric patients. METHODS: A two-phase (retrospective and prospective) observational audit of pharmacists' interventions collected via notes made on their ward handover information sheets and patient case notes was conducted over a 2-year period in a tertiary paediatric hospital. A patient prioritization tool was created based on pharmacists' interventions in real time. This tool could be used at the start of the working day (without the need to review the patient or their case notes) to identify patients who would benefit most from a clinical pharmacist review. The tool was validated for effectiveness and selectivity. RESULTS AND DISCUSSION: The tool was easy to use and effective in identifying that 43% of paediatric inpatients did not require a routine clinical pharmacist review. It had 98% specificity in identifying patients who require a pharmacist intervention. It could be easily used at the start of the day to select patients for pharmacist review. WHAT IS NEW AND CONCLUSION: A new patient prioritization tool has been developed and validated for identifying paediatric inpatients requiring clinical pharmacist review.

Identification of a Sjögren's syndrome susceptibility locus at OAS1 that influences isoform switching, protein expression, and responsiveness to type I interferons.

Sjögren's syndrome (SS) is a common, autoimmune exocrinopathy distinguished by keratoconjunctivitis sicca and xerostomia. Patients frequently develop serious complications including lymphoma, pulmonary dysfunction, neuropathy, vasculitis, and debilitating fatigue. Dysregulation of type I interferon (IFN) pathway is a prominent feature of SS and is correlated with increased autoantibody titers and disease severity. To identify genetic determinants of IFN pathway dysregulation in SS, we performed cis-expression quantitative trait locus (eQTL) analyses focusing on differentially expressed type I IFN-inducible transcripts identified through a transcriptome profiling study. Multiple cis-eQTLs were associated with transcript levels of 2'-5'-oligoadenylate synthetase 1 (OAS1) peaking at rs10774671 (PeQTL = 6.05 × 10-14). Association of rs10774671 with SS susceptibility was identified and confirmed through meta-analysis of two independent cohorts (Pmeta = 2.59 × 10-9; odds ratio = 0.75; 95% confidence interval = 0.66-0.86). The risk allele of rs10774671 shifts splicing of OAS1 from production of the p46 isoform to multiple alternative transcripts, including p42, p48, and p44. We found that the isoforms were differentially expressed within each genotype in controls and patients with and without autoantibodies. Furthermore, our results showed that the three alternatively spliced isoforms lacked translational response to type I IFN stimulation. The p48 and p44 isoforms also had impaired protein expression governed by the 3' end of the transcripts. The SS risk allele of rs10774671 has been shown by others to be associated with reduced OAS1 enzymatic activity and ability to clear viral infections, as well as reduced responsiveness to IFN treatment. Our results establish OAS1 as a risk locus for SS and support a potential role for defective viral clearance due to altered IFN response as a genetic pathophysiological basis of this complex autoimmune disease.

Completeness of protocols for clinical trials in children submitted to ethics committees.

AIM: Studies of published clinical trials involving children have shown frequent omissions in key aspects of design and conduct, but these problems may be artefactual and due to editorial processes and space limitations. To determine actual design and conduct, we analysed the completeness of key domains in trial protocols involving children submitted to Human Research Ethics Committees. METHODS: The ethics committees of all eight children's hospitals in Australia were invited to participate. De-identified trial protocols submitted for review in 2012 were evaluated using a checklist derived from Consolidated Standards of Reporting Trials, the Cochrane Risk of Bias Tool and Good Clinical Practice guidelines. RESULTS: Four ethics committees agreed to participate, and 69 protocols were analysed. The domains almost always reported were clustered around the background and trial plan (planned interventions for each group (99%), specific objectives (97%) and scientific background (96%)). Risk-of-bias domains such as random sequence generation and blinding of participants were often reported (75-90%). Domains least reported were clustered around the statistical analysis plan (66%), specified intention-to-treat analysis (54%), the justification for the proposed trial based upon a systematic review (48%) and age-specific outcomes (48%). CONCLUSIONS: Protocols of trials involving children assessed by ethics committees generally include details on background and basic design, but many key domains in trial design and conduct are not covered. Despite widespread recognition of how problems in the design and conduct of trials may lead to unreliable results, investigators still appear to be omitting key elements in trial protocols.

Using average nucleotide identity to improve taxonomic assignments in prokaryotic genomes at the NCBI.

Average nucleotide identity analysis is a useful tool to verify taxonomic identities in prokaryotic genomes, for both complete and draft assemblies. Using optimum threshold ranges appropriate for different prokaryotic taxa, we have reviewed all prokaryotic genome assemblies in GenBank with regard to their taxonomic identity. We present the methods used to make such comparisons, the current status of GenBank verifications, and recent developments in confirming species assignments in new genome submissions.

IRF4 and IRF8 Act in CD11c+ Cells To Regulate Terminal Differentiation of Lung Tissue Dendritic Cells.

Dendritic cells (DCs) initiate immune responses in barrier tissues including lung and skin. Conventional DC (cDC) subsets, CD11b(-) (cDC1s) or CD11b(+) (cDC2s), arise via distinct networks of transcription factors involving IFN regulatory factor 4 (IRF4) and IRF8, and are specialized for unique functional responses. Using mice in which a conditional Irf4 or Irf8 allele is deleted in CD11c(+) cells, we determined whether IRF4 or IRF8 deficiency beginning in CD11c(+) cDC precursors (pre-cDCs) changed the homeostasis of mature DCs or pre-DCs in the lung, dermis, and spleen. CD11c-cre-Irf4(-/-) mice selectively lacked a lung-resident CD11c(hi)CD11b(+)SIRPα(+)CD24(+) DC subset, but not other lung CD11b(+) DCs or alveolar macrophages. Numbers of CD11b(+)CD4(+) splenic DCs, but not CD11b(+) dermal DCs, were reduced, indicating cDC2s in the lung and dermis develop via different pathways. Irf4 deficiency did not alter numbers of cDC1s. CD11c-cre-Irf8(-/-) mice lacked lung-resident CD103(+) DCs and splenic CD8α(+) DCs, yet harbored increased IRF4-dependent DCs. This correlated with a reduced number of Irf8(-/-) pre-cDCs, which contained elevated IRF4, suggesting that Irf8 deficiency diverts pre-cDC fate. Analyses of Irf4 and Irf8 haploinsufficient mice showed that, although one Irf4 allele was sufficient for lung cDC2 development, two functional Irf8 alleles were required for differentiation of lung cDC1s. Thus, IRF8 and IRF4 act in pre-cDCs to direct the terminal differentiation of cDC1 and cDC2 subsets in the lung and spleen. These data suggest that variation in IRF4 or IRF8 levels resulting from genetic polymorphisms or environmental cues will govern tissue DC numbers and, therefore, regulate the magnitude of DC functional responses.

Bone Cancer: Diagnosis and Treatment Principles.

Primary bone cancers include osteosarcoma, Ewing sarcoma, and chondrosarcoma. They account for less than 1% of diagnosed cancers each year and are associated with significant morbidity and mortality. Timely diagnosis is challenging because of late patient presentation, nonspecific symptoms that mimic common musculoskeletal injuries, and low suspicion by physicians. Plain radiography is the preferred diagnostic test. Radiographic suspicion of a bone malignancy should prompt quick referral to a cancer center for multidisciplinary care. Osteosarcoma, the most common bone cancer, most often occurs in children and adolescents. It typically develops in the metaphysis of long bones, specifically the distal femur, proximal tibia, and proximal humerus. Metastasis to the lungs is common. Use of neoadjuvant and adjuvant chemotherapy, in combination with surgery, has improved survival rates to nearly 80% for patients with localized disease, and 90% to 95% of patients do not require limb amputation. Ewing sarcoma is the second most common bone cancer and is similar to osteosarcoma in terms of presenting symptoms, age at occurrence, and treatment. Prognosis for osteosarcoma and Ewing sarcoma depends on the presence of metastasis, which lowers the five-year survival rate to 20% to 30%. Chondrosarcoma is the rarest bone cancer, primarily affecting adults older than 40 years. Survival rates are higher because most of these tumors are low-grade lesions.

Rodent age-related impairments in discriminating perceptually similar objects parallel those observed in humans.

The ability to accurately remember distinct episodes is supported by high-level sensory discrimination. Performance on mnemonic similarity tasks, which test high-level discrimination, declines with advancing age in humans and these deficits have been linked to altered activity in hippocampal CA3 and dentate gyrus. Lesion studies in animal models, however, point to the perirhinal cortex as a brain region critical for sensory discriminations that serve memory. Reconciliation of the contributions of different regions within the cortical-hippocampal circuit requires the development of a discrimination paradigm comparable to the human mnemonic similarity task that can be used in rodents. In the present experiments, young and aged rats were cross-characterized on a spatial water maze task and two variants of an object discrimination task: one in which rats incrementally learned which object of a pair was rewarded and different pairs varied in their similarity (Experiment 1), and a second in which rats were tested on their ability to discriminate a learned target object from multiple lure objects with an increasing degree of feature overlap (Experiment 2). In Experiment 1, aged rats required more training than young to correctly discriminate between similar objects. Comparably, in Experiment 2, aged rats were impaired in discriminating a target object from lures when the pair shared more features. Discrimination deficits across experiments were correlated within individual aged rats, though, for the cohort tested, aged rats were not impaired overall in spatial learning and memory. This could suggest discrimination deficits emerging with age precede declines in spatial or episodic memory, an observation that has been made in humans. Findings of robust impairments in object discrimination abilities in the aged rats parallel results from human studies, supporting use of the developed tasks for mechanistic investigation of cortical-hippocampal circuit dysfunction in aging and disease.

A new LC-MS/MS bioanalytical method for perindopril and perindoprilat in human plasma and milk.

A first of its kind, simple, rapid, and sensitive liquid chromatography mass spectrometry (LC-MS/MS) method was developed and validated for quantification of perindopril and perindoprilat in both human plasma and breast milk. The analytes and internal standards (phenazone and acetyl salicylic acid) were extracted from biological matrices by protein precipitation. A Phenomenex® C-18 column was used to provide an appropriate chromatographic separation of the analytes, followed by detection with tandem mass spectrometry. Gradient chromatographic and mass spectrometric detection conditions with mobile phases (A: 5% methanol + 0.1% formic acid in water v/v, and B: 95% methanol + 0.1% formic acid in water v/v) were developed to achieve a LOQ of 0.5 ng/mL in both human plasma and milk. The method was suitable of evaluating clinical samples. The mass transition was followed as m/z 369.10/172.00 for perindopril, m/z 339.00/168.10 for perindoprilat, m/z 188.90/55.95 for phenazone, and m/z 179.04/137.02 for acetyl salicylic acid. The developed method was optimized and validated with a linear range of 0.1-200 ng/mL (r 2 = better than 0.99 for both perindopril and perindoprilat). The precision and accuracy values were within 15% CV. The overall recovery of the analytes was 80-110%. The method has good specificity and repeatability. Stability studies were conducted in both human plasma and bovine milk for up to 3 months, at the storage conditions of 25, 4, and -80 °C.

Discrimination performance in aging is vulnerable to interference and dissociable from spatial memory.

Hippocampal-dependent episodic memory and stimulus discrimination abilities are both compromised in the elderly. The reduced capacity to discriminate between similar stimuli likely contributes to multiple aspects of age-related cognitive impairment; however, the association of these behaviors within individuals has never been examined in an animal model. In the present study, young and aged F344×BN F1 hybrid rats were cross-characterized on the Morris water maze test of spatial memory and a dentate gyrus-dependent match-to-position test of spatial discrimination ability. Aged rats showed overall impairments relative to young in spatial learning and memory on the water maze task. Although young and aged learned to apply a match-to-position response strategy in performing easy spatial discriminations within a similar number of trials, a majority of aged rats were impaired relative to young in performing difficult spatial discriminations on subsequent tests. Moreover, all aged rats were susceptible to cumulative interference during spatial discrimination tests, such that error rate increased on later trials of test sessions. These data suggest that when faced with difficult discriminations, the aged rats were less able to distinguish current goal locations from those of previous trials. Increasing acetylcholine levels with donepezil did not improve aged rats' abilities to accurately perform difficult spatial discriminations or reduce their susceptibility to interference. Interestingly, better spatial memory abilities were not significantly associated with higher performance on difficult spatial discriminations. This observation, along with the finding that aged rats made more errors under conditions in which interference was high, suggests that match-to-position spatial discrimination performance may rely on extra-hippocampal structures such as the prefrontal cortex, in addition to the dentate gyrus.

IRF4 promotes cutaneous dendritic cell migration to lymph nodes during homeostasis and inflammation.

Migration of resident dendritic cells (DC) from the skin to local lymph nodes (LN) triggers T cell-mediated immune responses during cutaneous infection, autoimmune disease, and vaccination. In this study, we investigated whether the development and migration of skin-resident DC were regulated by IFN regulatory factor 4 (IRF4), a transcription factor that is required for the development of CD11b(+) splenic DC. We found that the skin of naive IRF4(-/-) mice contained normal numbers of epidermal Langerhans cells (eLC) and increased numbers of CD11b(+) and CD103(+) dermal DC (dDC) populations, indicating that tissue DC development and skin residency is not disrupted by IRF4 deficiency. In contrast, numbers of migratory eLC and CD11b(+) dDC were significantly reduced in the cutaneous LN of IRF4(-/-) mice, suggesting a defect in constitutive migration from the dermis during homeostasis. Upon induction of skin inflammation, CD11b(+) dDC in IRF4(-/-) mice did not express the chemokine receptor CCR7 and failed to migrate to cutaneous LN, whereas the migration of eLC was only mildly impaired. Thus, although dispensable for their development, IRF4 is crucial for the CCR7-mediated migration of CD11b(+) dDC, a predominant population in murine and human skin that plays a vital role in normal and pathogenic cutaneous immunity.

A national study of the processes and outcomes of paediatric formulary applications in Australia.

OBJECTIVE: To evaluate the processes by which pharmaceuticals are added to the formularies of Australian paediatric hospitals. DESIGN: Descriptive study of the processes and outcomes of all submissions to Australian paediatric hospital drug and therapeutics committees from 1 July 2010 to 31 December 2011. SETTING: All eight tertiary paediatric hospitals in Australia. PARTICIPANTS: Interviews with committee secretaries or delegates and document analysis. MAIN OUTCOME MEASURES: Total number of formulary applications, stratified by therapeutic class, approval rates for each hospital and quality of supporting information. RESULTS: One hundred and twenty applications were considered during the study period, with most applications approved (range, 67%-100%). Neurological agents were the most common therapeutic class considered. A conflict of interest was declared for 10 applications (8%). Forty-five (38%) were independently reviewed by a statewide medicines advisory committee or hospital pharmacist. Several committees approved identical applications during the period of review and with different outcomes. For applications submitted for new drugs or new indications (95 applications), supporting data included randomised controlled trials (37/95), case series (36/95), product information (34/95) and narrative reviews (29/95). Few applications (14/95) included a systematic review or meta-analysis. No application included an evaluation of the risk of bias of supporting studies. CONCLUSIONS: There is limited high-quality evidence informing paediatric hospital-based drug approvals. Approval processes vary considerably among institutions with substantial duplication of effort and variable outcomes. Resources and training appear insufficient given the technical complexity of submissions. A national, standardised approach to hospital-based drug evaluation could reduce overlap and improve decision making.

Hydropower capacity factors trending down in the United States.

The United States hydropower fleet has faced increasing environmental and regulatory pressures over the last half century, potentially constraining total generation. Here we show that annual capacity factor has declined at four fifths of United States hydropower plants since 1980, with two thirds of decreasing trends significant at p < 0.05. Results are based on an analysis of annual energy generation totals and nameplate capacities for 610 plants (>5 megawatt), representing 87% of total conventional hydropower capacity in the United States. On aggregate, changes in capacity factor imply a fleetwide, cumulative generation decrease of 23% since 1980 before factoring in capacity upgrades-akin to retiring a Hoover Dam once every two to three years. Changes in water availability explain energy decline in only 21% of plants, highlighting the importance of non-climatic drivers of generation, including deterioration of plant equipment as well as changes to dam operations in support of nonpower objectives.

Gram-Positive Bacteria Cell Wall Peptidoglycan Polymers Activate Human Dendritic Cells to Produce IL-23 and IL-1ß and Promote TH17 Cell Differentiation.

Gram-positive bacterial infections are a major cause of organ failure and mortality in sepsis. Cell wall peptidoglycan (PGN) is shed during bacterial replication, and Bacillus anthracis PGN promotes a sepsis-like pathology in baboons. Herein, we determined the ability of polymeric Bacillus anthracis PGN free from TLR ligands to shape human dendritic cell (DC) responses that are important for the initiation of T cell immunity. Monocyte-derived DCs from healthy donors were incubated with PGN polymers isolated from Bacillus anthracis and Staphylococcus aureus. PGN activated the human DCs, as judged by the increased expression of surface HLA-DR, CD83, the T cell costimulatory molecules CD40 and CD86, and the chemokine receptor CCR7. PGN elicited the DC production of IL-23, IL-6, and IL-1ß but not IL-12p70. The PGN-stimulated DCs induced the differentiation of naïve allogeneic CD4+ T cells into T helper (TH) cells producing IL-17 and IL-21. Notably, the DCs from a subset of donors did not produce significant levels of IL-23 and IL-1ß upon PGN stimulation, suggesting that common polymorphisms in immune response genes regulate the PGN response. In sum, purified PGN is a highly stimulatory cell wall component that activates human DCs to secrete proinflammatory cytokines and promote the differentiation of TH17 cells that are important for neutrophil recruitment in extracellular bacterial infections.

Blood myeloid cells differentiate to lung resident cells and respond to pathogen stimuli in a 3D human tissue-engineered lung model.

Introduction: Respiratory infections remain a leading global health concern. Models that recapitulate the cellular complexity of the lower airway of humans will provide important information about how the immune response reflects the interactions between diverse cell types during infection. We developed a 3D human tissue-engineered lung model (3D-HTLM) composed of primary human pulmonary epithelial and endothelial cells with added blood myeloid cells that allows assessment of the innate immune response to respiratory infection. Methods: The 3D-HTLM consists of small airway epithelial cells grown at air-liquid interface layered on fibroblasts within a collagen matrix atop a permeable membrane with pulmonary microvascular endothelial cells layered underneath. After the epithelial and endothelial layers had reached confluency, an enriched blood monocyte population, containing mostly CD14+ monocytes (Mo) with minor subsets of CD1c+ classical dendritic cells (cDC2s), monocyte-derived dendritic cells (Mo-DCs), and CD16+ non-classical monocytes, was added to the endothelial side of the model. Results: Immunofluorescence imaging showed the myeloid cells migrate through and reside within each layer of the model. The myeloid cell subsets adapted to the lung environment in the 3D-HTLM, with increased proportions of the recovered cells expressing lung tissue resident markers CD206, CD169, and CD163 compared with blood myeloid cells, including a population with features of alveolar macrophages. Myeloid subsets recovered from the 3D-HTLM displayed increased expression of HLA-DR and the co-stimulatory markers CD86, CD40, and PDL1. Upon stimulation of the 3D-HTLM with the toll-like receptor 4 (TLR4) agonist bacterial lipopolysaccharide (LPS), the CD31+ endothelial cells increased expression of ICAM-1 and the production of IL-10 and TNFα was dependent on the presence of myeloid cells. Challenge with respiratory syncytial virus (RSV) led to increased expression of macrophage activation and antiviral pathway genes by cells in the 3D-HTLM. Discussion: The 3D-HTLM provides a lower airway environment that promotes differentiation of blood myeloid cells into lung tissue resident cells and enables the study of respiratory infection in a physiological cellular context.