BTK inhibitor-induced defects in human neutrophil effector activity against Aspergillus fumigatus are restored by TNFα.

Inhibition of Bruton's tyrosine kinase (BTK) through covalent modifications of its active site (e.g., ibrutinib [IBT]) is a preferred treatment for multiple B cell malignancies. However, IBT-treated patients are more susceptible to invasive fungal infections, although the mechanism is poorly understood. Neutrophils are the primary line of defense against these infections; therefore, we examined the impact of IBT on primary human neutrophil effector activity against Aspergillus fumigatus. IBT significantly impaired the ability of neutrophils to kill A. fumigatus and potently inhibited reactive oxygen species (ROS) production, chemotaxis, and phagocytosis. Importantly, exogenous TNFα fully compensated for defects imposed by IBT and newer-generation BTK inhibitors and restored the ability of neutrophils to contain A. fumigatus hyphal growth. Blocking TNFα did not impact ROS production in healthy neutrophils but prevented exogenous TNFα from rescuing the phenotype of IBT-treated neutrophils. The restorative capacity of TNFα was independent of transcription. Moreover, the addition of TNFα immediately rescued ROS production in IBT-treated neutrophils indicating that TNFα worked through a BTK-independent signaling pathway. Finally, TNFα restored effector activity of primary neutrophils from patients on IBT therapy. Altogether, our data indicate that TNFα rescues the antifungal immunity block imposed by inhibition of BTK in primary human neutrophils.

Candida albicans extracellular vesicles trigger type I IFN signalling via cGAS and STING.

The host type I interferon (IFN) pathway is a major signature of inflammation induced by the human fungal pathogen, Candida albicans. However, the molecular mechanism for activating this pathway in the host defence against C. albicans remains unknown. Here we reveal that mice lacking cyclic GMP-AMP synthase (cGAS)-stimulator of IFN genes (STING) pathway components had improved survival following an intravenous challenge by C. albicans. Biofilm-associated C. albicans DNA packaged in extracellular vesicles triggers the cGAS-STING pathway as determined by induction of interferon-stimulated genes, IFNß production, and phosphorylation of IFN regulatory factor 3 and TANK-binding kinase 1. Extracellular vesicle-induced activation of type I IFNs was independent of the Dectin-1/Card9 pathway and did not require toll-like receptor 9. Single nucleotide polymorphisms in cGAS and STING potently altered inflammatory cytokine production in human monocytes challenged by C. albicans. These studies provide insights into the early innate immune response induced by a clinically significant fungal pathogen.

Lewy body dementia: Overcoming barriers and identifying solutions.

Despite its high prevalence among dementias, Lewy body dementia (LBD) remains poorly understood with a limited, albeit growing, evidence base. The public-health burden that LBD imposes is worsened by overlapping pathologies, which contribute to misdiagnosis, and lack of treatments. For this report, we gathered and analyzed public-domain information on advocacy, funding, research outputs, and the therapeutic pipeline to identify gaps in each of these key elements. To further understand the current gaps, we also conducted interviews with leading experts in regulatory/governmental agencies, LBD advocacy, academic research, and biopharmaceutical research, as well as with funding sources. We identified wide gaps across the entire landscape, the most critical being in research. Many of the experts participated in a workshop to discuss the prioritization of research areas with a view to accelerating therapeutic development and improving patient care. This white paper outlines the opportunities for bridging the major LBD gaps and creates the framework for collaboration in that endeavor. HIGHLIGHTS: A group representing academia, government, industry, and consulting expertise was convened to discuss current progress in Dementia with Lewy Body care and research. Consideration of expert opinion,natural language processing of the literature as well as publicly available data bases, and Delphi inspired discussion led to a proposed consensus document of priorities for the field.

Cross-kingdom anti-inflammatory effects of fungal melanin on airway epithelium by post-translational blockade of chemokine secretion.

Respiratory infections caused by the human fungal pathogens, Aspergillus fumigatus and Cryptococcus neoformans, are a major cause of mortality for immunocompromised patients. Exposure to these pathogens occurs through inhalation, although the role of the respiratory epithelium in disease pathogenesis has not been defined. Employing a primary human airway epithelial model, we demonstrate that fungal melanins potently block the post-translational secretion of CXCL1 and CXCL8 independent of transcription or the requirement of melanin to be phagocytosed, leading to a significant reduction of neutrophils to the apical airway both in vitro and in vivo. Aspergillus-derived melanin, a major constituent of the fungal cell wall, has far-reaching effects, dampening airway epithelial chemokine production in response to fungi, bacteria, and exogenous cytokines. Taken together, our results reveal a critical role for melanin interaction with airway epithelium in shaping the host response to fungal and bacterial pathogens.

The C-Type Lectin Receptor Dectin-2 Is a Receptor for Aspergillus fumigatus Galactomannan.

Aspergillus fumigatus is a ubiquitous environmental mold that causes significant mortality particularly among immunocompromised patients. The detection of the Aspergillus-derived carbohydrate galactomannan in patient serum and bronchoalveolar lavage fluid is the major biomarker used to detect A. fumigatus infection in clinical medicine. Despite the clinical relevance of this carbohydrate, we lack a fundamental understanding of how galactomannan is recognized by the immune system and its consequences. Galactomannan is composed of a linear mannan backbone with galactofuranose sidechains and is found both attached to the cell surface of Aspergillus and as a soluble carbohydrate in the extracellular milieu. In this study, we utilized fungal-like particles composed of highly purified Aspergillus galactomannan to identify a C-type lectin host receptor for this fungal carbohydrate. We identified a novel and specific interaction between Aspergillus galactomannan and the C-type lectin receptor Dectin-2. We demonstrate that galactomannan bound to Dectin-2 and induced Dectin-2-dependent signaling, including activation of spleen tyrosine kinase, gene transcription, and tumor necrosis factor alpha (TNF-α) production. Deficiency of Dectin-2 increased immune cell recruitment to the lungs but was dispensable for survival in a mouse model of pulmonary aspergillosis. Our results identify a novel interaction between galactomannan and Dectin-2 and demonstrate that Dectin-2 is a receptor for galactomannan, which leads to a proinflammatory immune response in the lung. IMPORTANCE Aspergillus fumigatus is a fungal pathogen that causes serious and often fatal disease in humans. The surface of Aspergillus is composed of complex sugar molecules. Recognition of these carbohydrates by immune cells by carbohydrate lectin receptors can lead to clearance of the infection or, in some cases, benefit the fungus by dampening the host response. Galactomannan is a carbohydrate that is part of the cell surface of Aspergillus but is also released during infection and is found in patient lungs as well as their bloodstreams. The significance of our research is that we have identified Dectin-2 as a mammalian immune cell receptor that recognizes, binds, and signals in response to galactomannan. These results enhance our understanding of how this carbohydrate interacts with the immune system at the site of infection and will lead to broader understanding of how release of galactomannan by Aspergillus effects the immune response in infected patients.

Deferoxamine prevents poststroke memory impairment in female diabetic rats: potential links to hemorrhagic transformation and ferroptosis.

Diabetes increases the risk of poststroke cognitive impairment (PSCI). Greater hemorrhagic transformation (HT) after stroke is associated with vasoregression and cognitive decline in male diabetic rats. Iron chelator deferoxamine (DFX) prevents vasoregression and improves outcomes. Although diabetic female rats develop greater HT, its impact on poststroke cerebrovascularization and cognitive outcomes remained unknown. We hypothesized that diabetes mediates pathological neovascularization, and DFX attenuates poststroke cerebrovascular remodeling and improves neurological outcomes in female diabetic rats. Female control and diabetic animals were treated with DFX or vehicle for 7 days after stroke. Vascular indices, microglial activation, and blood-brain barrier (BBB) integrity were evaluated on day 14. Results from diabetic female rats were partially compared with our previously published findings in male counterparts. Hemin-induced programmed cell death was studied in male and female brain microvascular endothelial cell lines (BMVEC). There was no vasoregression after stroke in either control or diabetic female animals. DFX prevented diabetes-mediated gliovascular remodeling and compromised BBB integrity while improving memory function in diabetes. Comparisons of female and male rats indicated sex differences in cognitive and vascular outcomes. Hemin mediated ferroptosis in both male and female BMVECs. DFX improved survival but had differential effects on ferroptosis signaling in female and male cells. These results suggest that stroke and associated HT do not affect cerebrovascularization in diabetic female rats, but iron chelation may provide a novel therapeutic strategy in the prevention of poststroke memory impairment in females with diabetes via the preservation of gliovascular integrity and improvement of endothelial cell survival.NEW & NOTEWORTHY The current study shows for the first time that diabetes does not promote aberrant cerebrovascularization in female rats. This contrasts with what we reported in male animals in various diabetes models. Deferoxamine preserved recognition memory function in diabetic female animals after stroke. The effect(s) of stroke and deferoxamine on cerebrovascular density and microglial activation also appear(s) to be different in female diabetic rats. Lastly, deferoxamine exerts detrimental effects on animals and BMVECs under control conditions.

Human Airway Epithelium Responses to Invasive Fungal Infections: A Critical Partner in Innate Immunity.

The lung epithelial lining serves as the primary barrier to inhaled environmental toxins, allergens, and invading pathogens. Pulmonary fungal infections are devastating and carry high mortality rates, particularly in those with compromised immune systems. While opportunistic fungi infect primarily immunocompromised individuals, endemic fungi cause disease in immune competent and compromised individuals. Unfortunately, in the case of inhaled fungal pathogens, the airway epithelial host response is vastly understudied. Furthering our lack of understanding, very few studies utilize primary human models displaying pseudostratified layers of various epithelial cell types at air-liquid interface. In this review, we focus on the diversity of the human airway epithelium and discuss the advantages and disadvantages of oncological cell lines, immortalized epithelial cells, and primary epithelial cell models. Additionally, the responses by human respiratory epithelial cells to invading fungal pathogens will be explored. Future investigations leveraging current human in vitro model systems will enable identification of the critical pathways that will inform the development of novel vaccines and therapeutics for pulmonary fungal infections.

Harnessing the Potential of Multiomics Studies for Precision Medicine in Infectious Disease.

The field of infectious diseases currently takes a reactive approach and treats infections as they present in patients. Although certain populations are known to be at greater risk of developing infection (eg, immunocompromised), we lack a systems approach to define the true risk of future infection for a patient. Guided by impressive gains in "omics" technologies, future strategies to infectious diseases should take a precision approach to infection through identification of patients at intermediate and high-risk of infection and deploy targeted preventative measures (ie, prophylaxis). The advances of high-throughput immune profiling by multiomics approaches (ie, transcriptomics, epigenomics, metabolomics, proteomics) hold the promise to identify patients at increased risk of infection and enable risk-stratifying approaches to be applied in the clinic. Integration of patient-specific data using machine learning improves the effectiveness of prediction, providing the necessary technologies needed to propel the field of infectious diseases medicine into the era of personalized medicine.

The Known Unknowns of the Immune Response to Coccidioides.

Coccidioidomycosis, otherwise known as Valley Fever, is caused by the dimorphic fungi Coccidioides immitis and C. posadasii. While most clinical cases present with self-limiting pulmonary infection, dissemination of Coccidioides spp. results in prolonged treatment and portends higher mortality rates. While the structure, genome, and niches for Coccidioides have provided some insight into the pathogenesis of disease, the underlying immunological mechanisms of clearance or inability to contain the infection in the lung are poorly understood. This review focuses on the known innate and adaptive immune responses to Coccidioides and highlights three important areas of uncertainty and potential approaches to address them. Closing these gaps in knowledge may enable new preventative and therapeutic strategies to be pursued.

The first line of defense: effector pathways of anti-fungal innate immunity.

The innate immune system is critical to proper host defense against fungal pathogens, which is highlighted by increased susceptibility to invasive disease in immunocompromised patients. Innate cells (e.g. macrophages, neutrophils, dendritic cells, eosinophils) are equipped with intricate cell machinery to detect invading fungi and facilitate fungal killing, recruit additional immune cells, and direct the adaptive immune system responses. Understanding the mechanisms that govern a protective response will enable the development of novel treatment strategies. This review focuses on recent insights of signaling and regulation of C-type lectin receptors and their effector mechanisms enabling an effective host antifungal immunity.

Diabetic rats are more susceptible to cognitive decline in a model of microemboli-mediated vascular contributions to cognitive impairment and dementia.

Vascular disease plays an important role in all kinds of cognitive impairment and dementia. Diabetes increases the risk of vascular disease and dementia. However, it is not clear how existing vascular disease in the brain accelerates the development of small vessel disease and promotes cognitive dysfunction in diabetes. We used microemboli (ME) injection model in the current study to test the hypothesis that cerebrovascular dysfunction in diabetes facilitates entrapment of ME leading to inflammation and cognitive decline. We investigated cognitive function, axonal/white matter (WM) changes, neurovascular coupling, and microglial activation in control and diabetic male and female Wistar rats subjected to sham or low/high dose ME injection. Diabetic male animals had cognitive deficits, WM demyelination and greater microglial activation than the control animals even at baseline. Functional hyperemia gradually declined in diabetic male animals after ME injection. Both low and high ME injection worsened WM damage and increased microglial activation in diabetic male and female animals. Low ME did not cause cognitive decline in controls, while promoting learning/memory deficits in diabetic female rats and no further decline in diabetic male animals. High ME led to cognitive decline in control male rats and exacerbated the deficits in diabetic cohort. These results suggest that the existing cerebrovascular dysfunction in diabetes may facilitate ME-mediated demyelination leading to cognitive decline. It is important to integrate comorbidities/sex as a biological variable into experimental models for the development of preventive or therapeutic targets.

Aspergillus fumigatus Cell Wall Promotes Apical Airway Epithelial Recruitment of Human Neutrophils.

Aspergillus fumigatus is a ubiquitous fungal pathogen capable of causing multiple pulmonary diseases, including invasive aspergillosis, chronic necrotizing aspergillosis, fungal colonization, and allergic bronchopulmonary aspergillosis. Intact mucociliary barrier function and early airway neutrophil responses are critical for clearing fungal conidia from the host airways prior to establishing disease. Following inhalation, Aspergillus conidia deposit in the small airways, where they are likely to make their initial host encounter with epithelial cells. Challenges in airway infection models have limited the ability to explore early steps in the interactions between A. fumigatus and the human airway epithelium. Here, we use inverted air-liquid interface cultures to demonstrate that the human airway epithelium responds to apical stimulation by A. fumigatus to promote the transepithelial migration of neutrophils from the basolateral membrane surface to the apical airway surface. Promoting epithelial transmigration with Aspergillus required prolonged exposure with live resting conidia. Swollen conidia did not expedite epithelial transmigration. Using A. fumigatus strains containing deletions of genes for cell wall components, we identified that deletion of the hydrophobic rodlet layer or dihydroxynaphthalene-melanin in the conidial cell wall amplified the epithelial transmigration of neutrophils, using primary human airway epithelium. Ultimately, we show that an as-yet-unidentified nonsecreted cell wall protein is required to promote the early epithelial transmigration of human neutrophils into the airspace in response to A. fumigatus Together, these data provide critical insight into the initial epithelial host response to Aspergillus.

Recurrent spontaneous pneumothoraces and vaping in an 18-year-old man: a case report and review of the literature.

BACKGROUND: Primary spontaneous pneumothorax is a common disorder occurring in young adults without underlying lung disease. Although tobacco smoking is a well-documented risk factor for spontaneous pneumothorax, an association between electronic cigarette use (that is, vaping) and spontaneous pneumothorax has not been noted. We report a case of spontaneous pneumothoraces correlated with vaping. CASE PRESENTATION: An 18-year-old Caucasian man presented twice with recurrent right-sided spontaneous pneumothoraces within 2 weeks. He reported a history of vaping just prior to both episodes. Diagnostic testing was notable for a right-sided spontaneous pneumothorax on chest X-ray and computed tomography scan. His symptoms improved following insertion of a chest tube and drainage of air on each occasion. In the 2-week follow-up visit for the recurrent episode, he was asymptomatic and reported that he was no longer using electronic cigarettes. CONCLUSIONS: Providers and patients should be aware of the potential risk of spontaneous pneumothorax associated with electronic cigarettes.

CD82 controls CpG-dependent TLR9 signaling.

The tetraspanin CD82 is a potent suppressor of tumor metastasis and regulates several processes including signal transduction, cell adhesion, motility, and aggregation. However, the mechanisms by which CD82 participates in innate immunity are unknown. We report that CD82 is a key regulator of TLR9 trafficking and signaling. TLR9 recognizes unmethylated cytosine-phosphate-guanine (CpG) motifs present in viral, bacterial, and fungal DNA. We demonstrate that TLR9 and CD82 associate in macrophages, which occurs in the endoplasmic reticulum (ER) and post-ER. Moreover, CD82 is essential for TLR9-dependent myddosome formation in response to CpG stimulation. Finally, CD82 modulates TLR9-dependent NF-κB nuclear translocation, which is critical for inflammatory cytokine production. To our knowledge, this is the first time a tetraspanin has been implicated as a key regulator of TLR signaling. Collectively, our study demonstrates that CD82 is a specific regulator of TLR9 signaling, which may be critical in cancer immunotherapy approaches and coordinating the innate immune response to pathogens.-Khan, N. S., Lukason, D. P., Feliu, M., Ward, R. A., Lord, A. K., Reedy, J. L., Ramirez-Ortiz, Z. G., Tam, J. M., Kasperkovitz, P. V., Negoro, P. E., Vyas, T. D., Xu, S., Brinkmann, M. M., Acharaya, M., Artavanis-Tsakonas, K., Frickel, E.-M., Becker, C. E., Dagher, Z., Kim, Y.-M., Latz, E., Ploegh, H. L., Mansour, M. K., Miranti, C. K., Levitz, S. M., Vyas, J. M. CD82 controls CpG-dependent TLR9 signaling.

Tetraspanin CD82 Organizes Dectin-1 into Signaling Domains to Mediate Cellular Responses to Candida albicans.

Tetraspanins are a family of proteins possessing four transmembrane domains that help in lateral organization of plasma membrane proteins. These proteins interact with each other as well as other receptors and signaling proteins, resulting in functional complexes called "tetraspanin microdomains." Tetraspanins, including CD82, play an essential role in the pathogenesis of fungal infections. Dectin-1, a receptor for the fungal cell wall carbohydrate ß-1,3-glucan, is vital to host defense against fungal infections. The current study identifies a novel association between tetraspanin CD82 and Dectin-1 on the plasma membrane of Candida albicans-containing phagosomes independent of phagocytic ability. Deletion of CD82 in mice resulted in diminished fungicidal activity, increased C. albicans viability within macrophages, and decreased cytokine production (TNF-α, IL-1ß) at both mRNA and protein level in macrophages. Additionally, CD82 organized Dectin-1 clustering in the phagocytic cup. Deletion of CD82 modulates Dectin-1 signaling, resulting in a reduction of Src and Syk phosphorylation and reactive oxygen species production. CD82 knockout mice were more susceptible to C. albicans as compared with wild-type mice. Furthermore, patient C. albicans-induced cytokine production was influenced by two human CD82 single nucleotide polymorphisms, whereas an additional CD82 single nucleotide polymorphism increased the risk for candidemia independent of cytokine production. Together, these data demonstrate that CD82 organizes the proper assembly of Dectin-1 signaling machinery in response to C. albicans.

Toxicological and pharmacological assessment of AGEN1884, a novel human IgG1 anti-CTLA-4 antibody.

CTLA-4 and CD28 exemplify a co-inhibitory and co-stimulatory signaling axis that dynamically sculpts the interaction of antigen-specific T cells with antigen-presenting cells. Anti-CTLA-4 antibodies enhance tumor-specific immunity through a variety of mechanisms including: blockade of CD80 or CD86 binding to CTLA-4, repressing regulatory T cell function and selective elimination of intratumoral regulatory T cells via an Fcγ receptor-dependent mechanism. AGEN1884 is a novel IgG1 antibody targeting CTLA-4. It potently enhanced antigen-specific T cell responsiveness that could be potentiated in combination with other immunomodulatory antibodies. AGEN1884 was well-tolerated in non-human primates and enhanced vaccine-mediated antigen-specific immunity. AGEN1884 combined effectively with PD-1 blockade to elicit a T cell proliferative response in the periphery. Interestingly, an IgG2 variant of AGEN1884 revealed distinct functional differences that may have implications for optimal dosing regimens in patients. Taken together, the pharmacological properties of AGEN1884 support its clinical investigation as a single therapeutic and combination agent.

Behavioral development and sociodemographics of infants and young children at higher and lower risk for autism spectrum disorders.

Identification of early signs of Autism Spectrum Disorder (ASD) could lead to earlier diagnosis and intervention. This cross-sectional study used the Parent Observation of Early Markers Scale (POEMS, Feldman et al. in J Autism Dev Disord 42:13-12, 2012) to identify early signs of ASD in 69 ASD high-risk (older sibling diagnosed with ASD) and 69 sex and aged-matched ASD low-risk second-born or later infants (no family history of ASD) between 6 and 36 months of age. Family sociodemographic comparisons were also made between the risk groups. The high-risk children had significantly more elevated POEMS items than the low-risk children at 12, 18, 24, 30 and 36 months of age, even when the children subsequently diagnosed with ASD were removed from the analyses. Families of the high-risk group had older parents, lower family income and fewer mothers working out of the home than the low-risk group. These sociodemographic variables were not significantly correlated with POEMS scores. The results suggest that high-risk infants may show signs of the broader ASD phenotype as early as 12 months of age that may be unrelated to observed sociodemographic family differences.

Development and initial validation of a parent report measure of the behavioral development of infants at risk for autism spectrum disorders.

We developed and evaluated a new parent report instrument--Parent Observation of Early Markers Scale (POEMS)--to monitor the behavioral development of infants at risk for autism spectrum disorder (ASD) because they have older affected siblings. Parents of 108 at-risk infants (74 males, 34 females) completed the POEMS from child age 1-24 months. The POEMS had acceptable psychometric properties and promising predictive validity. Most concerning items were social and communication deficits, and intolerance to waiting. Results provide preliminary evidence that prospective parent report measures can help to detect early ASD symptoms in infants at biological risk. We invite researchers to join us in multi-center studies of the POEMS.