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Objective: We aimed to understand the potential therapeutic and anti-inflammatory effects of the phosphodiesterase-4 (PDE4) inhibitor roflumilast in models of pulmonary infection caused by betacoronaviruses. Methods: Mice were infected intranasally with murine hepatitis virus (MHV-3) or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Roflumilast was given to MHV-3-infected mice therapeutically at doses of 1 mg/kg or 10 mg/kg, or prophylactically at 10 mg/kg. In SARS-CoV-2-infected mice, roflumilast was given therapeutically at a dose of 10 mg/kg. Lung histopathology, chemokines (CXCL-1 and CCL2), cytokines (IL-1β, IL-6, TNF, IFN-γ, IL-10 and TGFβ), neutrophil immunohistochemical staining (Ly6G+ cells), macrophage immunofluorescence staining (F4/80+ cells), viral titration plaque assay, real-time PCR virus detection, and blood cell counts were examined. Results: Therapeutic treatment with roflumilast at 10 mg/kg reduced lung injury in SARS-CoV-2 or MHV-3-infected mice without compromising viral clearance. In MHV-3-infected mice, reduced lung injury was associated with decreased chemokines levels, prevention of neutrophil aggregates and reduced macrophage accumulation in the lung tissue. However, the prophylactic treatment strategy with roflumilast increased lung injury in MHV-3-infected mice. Conclusion: Our findings indicate that therapeutic treatment with roflumilast reduced lung injury in MHV-3 and SARS-CoV-2 lung infections. Given the protection induced by roflumilast in inflammation, PDE4 targeting could be a promising therapeutic avenue worth exploring following severe viral infections of the lung. [ABSTRACT FROM AUTHOR]

Rationale: Elevated levels of CD11c+ myeloid cells are observed in various pulmonary disorders, including Idiopathic Pulmonary Fibrosis (IPF). Dendritic cells (DCs) and macrophages (MΦ) are critical antigen‐presenting cells (APCs) that direct adaptive immunity. However, the role of CD11c+ myeloid cells in lung extracellular matrix (ECM) accumulation and pulmonary fibrosis is poorly understood. Objective: We aimed to investigate the impact of depleting CD11c+ myeloid cells, including DCs and macrophages, during bleomycin‐induced pulmonary fibrosis in mice. Methods: We used a diphtheria toxin (DTx) receptor (DTR) transgenic mouse model (CD11c‐DTR‐Tg) to deplete CD11c+ myeloid cells through two methods: Systemic Depletion (SD) via intraperitoneal injection (i.p.) and local depletion (LD) via intranasal instillation (i.n.). We then assessed the effects of CD11c+ cell depletion during bleomycin‐induced lung inflammation and fibrosis. Results: Fourteen days after bleomycin instillation, there was a progressive accumulation of myeloid cells, specifically F4/80‐MHCII+CD11c+ DCs and F4/80 + MHCII+CD11c+ MΦ, preceding mortality and pulmonary fibrosis. Systemic depletion of CD11c+ DCs and MΦ via i.p. DTx administration in CD11c‐DTR‐Tg mice protected against bleomycin‐induced mortality and pulmonary fibrosis compared to wild‐type (WT) mice. Systemic depletion reduced myeloid cells, airway inflammation (total leukocytes, neutrophils, and CD4+ lymphocytes in bronchoalveolar lavage (BAL), inflammatory and fibrogenic mediators, and fibrosis‐related mRNAs (Collagen‐1α1 and α‐SMA). Increased anti‐inflammatory cytokine IL‐10 and CXCL9 levels were observed, resulting in lower lung hydroxyproline content and Ashcroft fibrosis score. Conversely, local depletion of CD11c+ cells increased mortality by acute leukocyte influx (predominantly neutrophils, DCs, and MΦ in BAL) correlated to IL‐1β, with lung hyper‐inflammation and early fibrosis development. Conclusion: Systemic depletion of CD11c+ cells confers protection against inflammation and fibrosis induced by Bleomycin, underscoring the significance of myeloid cells expressing F4/80‐MHCII+CD11c+ DCs and F4/80 + MHCII+CD11c+ MΦ orchestrating the inflammatory milieu within the lungs, potentially as a source of cytokines sustaining pulmonary chronic inflammation leading to progressive fibrosis and mortality. [ABSTRACT FROM AUTHOR]

Neurodegenerative disorders, including traumatic injuries to the central nervous system (CNS) and neurodegenerative diseases, are characterized by early axonal damage, which does not regenerate in the adult mammalian CNS, leading to permanent neurological deficits. One of the primary causes of the loss of regenerative ability is thought to be a developmental decline in neurons' intrinsic capability for axon growth. Different molecules are involved in the developmental loss of the ability for axon regeneration, including many transcription factors. However, the function of microRNAs (miRNAs), which are also modulators of gene expression, in axon re-growth is still unclear. Among the various miRNAs recently identified with roles in the CNS, miR-17, which is highly expressed during early development, emerges as a promising target to promote axon regeneration. Here, we used adeno-associated viral (AAV) vectors to overexpress miR-17 (AAV.miR-17) in primary cortical neurons and evaluate its effects on neurite and axon regeneration in vitro. Although AAV.miR-17 had no significant effect on neurite outgrowth and arborization, it significantly enhances neurite regeneration after scratch lesion and axon regeneration after axotomy of neurons cultured in microfluidic chambers. Target prediction and functional annotation analyses suggest that miR-17 regulates gene expression associated with autophagy and cell metabolism. Our findings suggest that miR-17 promotes regenerative response and thus could mitigate neurodegenerative effects. [ABSTRACT FROM AUTHOR]

Introduction: People with hazardous alcohol use are more susceptible to viral, bacterial, and fungal infections due to the effect of alcohol on immune system cell function. Metabolized ethanol reduces NAD+ to NADH, affecting critical metabolic pathways. Here, our aim was to investigate whether alcohol is metabolized by bone marrow cells and if it impacts the metabolic pathways of leukocyte progenitor cells. This is said to lead to a qualitative and quantitative alteration of key metabolites which may be related to the immune response. Methods: We addressed this aim by using C57BL/6 mice under chronic ethanol administration and evaluating the metabolomic profile of bone marrow total cells by gas chromatography-coupled mass spectrometry (GC-MS). Results: We identified 19 metabolites. Our data demonstrated that chronic ethanol administration alters the metabolomic profile in the bone marrow, resulting in a statistically diminished abundance of five metabolites in ethanol- treated animals: uracil, succinate, proline, nicotinamide, and tyrosine. Discussion: Our results demonstrate for the first time in the literature the effects of alcohol consumption on the metabolome content of hematopoietic tissue and open a wide range of further studies to investigate mechanisms by which alcohol compromises the cellular function of the immune system. [ABSTRACT FROM AUTHOR]

Rationale: The FDA-approved Dimethyl Fumarate (DMF) as an oral drug for Multiple Sclerosis (MS) treatment based on its immunomodulatory activities. However, it also caused severe adverse effects mainly related to the gastrointestinal system. Objective: Investigated the potential effects of solid lipid nanoparticles (SLNs) containing DMF, administered by inhalation on the clinical signs, central nervous system (CNS) inflammatory response, and lung function changes in mice with experimental autoimmune encephalomyelitis (EAE). Materials and methods: EAE was induced using MOG35-55 peptide in female C57BL/6J mice and the mice were treated via inhalation with DMF-encapsulated SLN (CTRL/SLN/DMF and EAE/SLN/DMF), empty SLN (CTRL/SLN and EAE/SLN), or saline solution (CTRL/saline and EAE/saline), every 72 h during 21 days. Results: After 21 days post-induction, EAE mice treated with DMF-loaded SLN, when compared with EAE/saline and EAE/SLN, showed decreased clinical score and weight loss, reduction in brain and spinal cord injury and inflammation, also related to the increased influx of Foxp3+ cells into the spinal cord and lung tissues. Moreover, our data revealed that EAE mice showed signs of respiratory disease, marked by increased vascular permeability, leukocyte influx, production of TNF-α and IL-17, perivascular and peribronchial inflammation, with pulmonary mechanical dysfunction associated with loss of respiratory volumes and elasticity, which DMF-encapsulated reverted in SLN nebulization. Conclusion: Our study suggests that inhalation of DMF-encapsulated SLN is an effective therapeutic protocol that reduces not only the CNS inflammatory process and disability progression, characteristic of EAE disease, but also protects mice from lung inflammation and pulmonary dysfunction. [ABSTRACT FROM AUTHOR]

Here, we characterize the Aspergillus fumigatus homologue ncsA Neuronal Calcium Sensor. We showed that ncsA is not an essential gene and ∆ncsA growth was decreased in the presence of EGTA and SDS. Furthermore, the ∆ncsA mutant is more resistant to calcium chloride. NcsA:mRFP localizes to the cytoplasm and its cellular localization is not affected by the cellular response to either calcium chloride or EGTA. The ∆ncsA mutant strain is more sensitive to voriconazole, itraconazole, and amphotericin. Polar growth in the ΔncsA mutant was also considerably more affected by lovastatin than in the wild type strain. The Spitzenkörper can be visualized in both strains and although the vacuolar system does not seem to be very different, there is an increase in the staining intensity on the germling surface of the ∆ncsA strain. NcsA promotes pmcA and pmcB expression and therefore there is a reduced expression of these ion pumps in the ΔncsA mutant background, and also of other genes involved in the response to calcium in A. fumigatus. The ncsA inactivation mutation is not causing loss of virulence in a low dose murine infection when compared to the corresponding wild type strain. [ABSTRACT FROM AUTHOR]

Background and Purpose Experimental approach Key Results Conclusions and Implications Prolonged survival of neutrophils is essential for determining the progression and severity of inflammatory and immune‐mediated disorders, including gouty arthritis. Survivin, an anti‐apoptotic molecule, has been described as a regulator of cell survival. This study aims to examine the effects of YM155 treatment, a survivin selective suppressant, in maintaining neutrophil survival in vitro and in vivo experimental settings of neutrophilic inflammation.BALB/c mice were injected with monosodium urate (MSU) crystals and treated with YM155 (intra‐articularly) at the peak of inflammatory response. Leukocyte recruitment, apoptosis neutrophil and efferocytosis were determined by knee joint wash cell morphology counting and flow cytometry. Resolution interval (Ri) was quantified by neutrophil infiltration, monitoring the amplitude and duration of the inflammation. Cytokine production was measured by ELISA. Mechanical hypernociception was assessed using an electronic von Frey aesthesiometer. Efferocytosis was evaluated in zymosan‐induced neutrophilic peritonitis. Survivin and cleaved caspase‐3 expression was determined in human neutrophils by flow cytometry.Survivin was expressed in neutrophils during MSU‐induced gout, and the treatment with YM155 reduced survivin expression and shortened Ri from ∼8 h observed in vehicle‐treated mice to ∼5.5 h, effect accompanied by increased neutrophil apoptosis and efferocytosis, both crucial for the inflammation resolution. Reduced IL‐1β and CXCL1 levels were also observed in periarticular tissue. YM155 reduced histopathological score and hypernociceptive response. In human neutrophils, lipopolysaccharide (LPS) increased survivin expression, whereas survivin inhibition with YM155 induced neutrophil apoptosis, with activation of caspase‐3.Survivin may be a promising therapeutic target to control neutrophilic inflammation. [ABSTRACT FROM AUTHOR]

Aspergillus fumigatus is a common widespread microorganism with environmental, biological and clinical relevance. After inhalation, swollen conidia can germinate, colonize and invade pulmonary tissues. Eosinophils have been described as key cells in A. fumigatus lung infection. However, their specific role in protecting or damaging lung tissue as well as their relatioship among different A. fumigatus strains is poorly understood. Previously, it has been reported that eosinophils are able to produce IL-17 and mediate an innate response that protected mice from infection using Af293 and CEA10 strains. Here, we have developed a set of new experiments with the CEA17-derived A1163 strain of A. fumigatus . Using ΔdblGATA1 mice, we demonstrate that eosinophils produce IL-17 and are involved in control of neutrophil, macrophage and lymphocyte recruitment. We found that eosinophils also induce high levels of cytokines and chemokines, generating an intense inflammatory process. Eosinophils are responsible for increased pulmonary dysfunction and elevated lethality rates in mice. Curiously, fungal burden was not affected. To address the role of IL-17 signaling, pharmacological inhibition of this mediator in the airways with anti-IL-17 antibody was able to reduce inflammation in the airways and protect infected mice. In conclusion, our results demonstrate that eosinophils control IL-17-mediated response and contribute to lung pathology after A. fumigatus infection. Therefore, eosinophils may represent a potential target for controlling exacerbated inflammation and prevent tissue damage during this fungal infection.

Traditionally, disease is thought to result from an insufficient response of the host to infection, leading to increased replication of microorganisms and consequently disease. However, infection may not necessarily lead to disease and disease is not only the result of uncontrolled replication of a microorganism. Indeed, the inflammatory response triggered by certain infections is frequently the cause of tissue damage and death. The present review argues that it is possible to separate mechanisms necessary for the host response to deal with infection from those which cause unwanted inflammation and drive disease. By understanding mechanisms which drive disease and where/how interaction leads to disease, we may be able to devise novel therapies to alleviate suffering of patients. Below, we will describe three situations--influenza, dengue and sepsis--in which unwanted (excessive, misplaced or altered) inflammation is responsible for disease induction. In these three situations, we will also describe some examples of molecules which have been found to drive disease but appear not to be essential for the ability of the host to control infection.