Publications by authors named "John Christman"

Extracellular vesicles mediate intercellular communication by transporting biologically active macromolecules. Our prior studies have demonstrated that the nuclear factor of activated T cell cytoplasmic member 3 (NFATc3) is activated in mouse pulmonary macrophages in response to lipopolysaccharide (LPS). Inhibition of NFATc3 activation by a novel cell-permeable calcineurin peptide inhibitor CNI103 mitigated the development of acute lung injury (ALI) in LPS-treated mice.

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Our previous research demonstrated that PU.1 regulates expression of the genes involved in inflammation in macrophages. Selective knockdown of PU.

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Objective: The study objective was to determine the effects a high protein (HP) vs. a high carbohydrate (HC) diet on cardiovascular risk factors (CVR), inflammation, metabolic parameters, oxidative stress, weight loss, lean and fat body mass, and remission of Type 2 Diabetes (T2DM) in subjects with obesity.

Research Design And Methods: Twelve women and men with T2D were recruited and randomized to either a HP (30%protein, 30%fat, 40%carbohydrate) (n = 6) or HC (15%protein, 30%fat, 55%carbohydrate) (n = 6) diet feeding study for 6 months in this randomized controlled trial.

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The prevalence of electronic cigarette (EC) use among adult with asthma has continued to increase over time, in part due to the belief of being less harmful than smoking. However, the extent of their toxicity and the involved mechanisms contributing to the deleterious impact of EC exposure on patients with preexisting asthma have not been delineated. In the present project, we tested the hypothesis that EC use contributes to respiratory damage and worsening inflammation in the lungs of patients with asthma.

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Background: Dendritic cells (DCs) are heterogeneous, comprising multiple subsets with unique functional specifications. Our previous work has demonstrated that the specific conventional type 2 DC subset, CSF1RcDC2s, plays a critical role in sensing aeroallergens.

Objective: It remains to be understood how CSF1RcDC2s recognize inhaled allergens.

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Idiopathic pulmonary fibrosis (IPF) is a progressive and highly lethal inflammatory interstitial lung disease characterized by aberrant extracellular matrix deposition. Macrophage activation by cytokines released from repetitively injured alveolar epithelial cells regulates the inflammatory response, tissue remodeling, and fibrosis throughout various phases of IPF. Our previous studies demonstrate that nuclear factor of activated T cells cytoplasmic member 3 (NFATc3) regulates a wide array of macrophage genes during acute lung injury pathogenesis.

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Introduction: Although the greater popularity of electronic cigarettes (EC) among asthmatics is alarming, there is limited knowledge of the long-term consequences of EC exposure in asthmatics.

Aims And Methods: Mild asthmatic C57/BL6J adult male and female mice were established by intranasal insufflation with three combined allergens. The asthmatic and age and sex-matched' naïve mice were exposed to air, nicotine-free (propylene glycol [PG]/vegetable glycerin [VG]-only), or PG/VG+Nicotine, 4 hours daily for 3 months.

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Idiopathic pulmonary fibrosis (IPF) is a progressive and highly lethal inflammatory interstitial lung disease characterized by aberrant extracellular matrix deposition. Macrophage activation by cytokines released from repetitively injured alveolar epithelial cells regulates the inflammatory response, tissue remodeling, and fibrosis throughout various phases of IPF. Our previous studies demonstrate that nuclear factor of activated T cells cytoplasmic member 3 (NFATc3) regulates a wide array of macrophage genes during acute lung injury pathogenesis.

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Transcriptional profiling studies have identified several protective genes upregulated in tubular epithelial cells during acute kidney injury (AKI). Identifying upstream transcriptional regulators could lead to the development of therapeutic strategies augmenting the repair processes. SOX9 is a transcription factor controlling cell-fate during embryonic development and adult tissue homeostasis in multiple organs including the kidneys.

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The resolution of inflammation is an active process coordinated by mediators and immune cells to restore tissue homeostasis. However, the mechanisms for resolving eosinophilic allergic lung inflammation triggered by inhaled allergens have not been fully elucidated. Our objectives were to investigate the cellular mechanism of tissue-resident macrophages involved in the resolution process of eosinophilic lung inflammation.

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Damage associated molecular patterns (DAMPs) are molecules released from dead/dying cells following toxicant and/or environmental exposures that activate the immune response through binding of pattern recognition receptors (PRRs). Excessive production of DAMPs or failed clearance leads to chronic inflammation and delayed inflammation resolution. One category of DAMPs are oxidized phospholipids (oxPLs) produced upon exposure to high levels of oxidative stress, such as following ozone (O) induced inflammation.

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Introduction: Patients with sepsis exhibit significant, persistent immunologic dysfunction. Evidence supports the hypothesis that epigenetic regulation of key cytokines plays an important role in this dysfunction. In sepsis, circulating microvesicles (MVs) containing elevated levels of DNA methyltransferase (DNMT) mRNA cause gene methylation and silencing in recipient cells.

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Asthma is phenotypically heterogeneous with several distinctive pathological mechanistic pathways. Previous studies indicate that neutrophilic asthma has a poor response to standard asthma treatments comprising inhaled corticosteroids. Therefore, it is important to identify critical factors that contribute to increased numbers of neutrophils in asthma patients whose symptoms are poorly controlled by conventional therapy.

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Introduction: Survivors of sepsis exhibit persistent immunosuppression. Epigenetic events may be responsible for some of these immunosuppressive changes. During sepsis circulating exosomes contain large quantities of DNA methyltransferase (DNMT) mRNAs.

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Unlabelled: Timely regulation of oxygen (Fio) is essential to prevent hyperoxemia or episodic hypoxemia. Exposure to excessive Fio is often noted early after onset of mechanical ventilation. In this pilot study, we examined the feasibility, safety, and efficacy of a clinical trial to prioritize Fio titration with electronic alerts to respiratory therapists.

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Background: Both hyperoxemia and hypoxemia are deleterious in critically ill patients. Targeted oxygenation is recommended to prevent both of these extremes, however this has not translated to the bedside. Hyperoxemia likely persists more than hypoxemia due to absence of immediate discernible adverse effects, cognitive biases and delay in prioritization of titration.

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Emerging data support the pivotal role of extracellular vesicles (EVs) in normal cellular physiology and disease conditions. However, despite their abundance, there is much less information about the lipid mediators carried in EVs, especially in the context of acute lung injury (ALI). Our data demonstrate that C57BL/6 mice subjected to intranasal Escherichia coli lipopolysaccharide (LPS)-induced ALI release, a higher number of EVs into the alveolar space, compared to saline-treated controls.

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The acute respiratory distress syndrome (ARDS) is a highly lethal condition that impairs lung function and causes respiratory failure. Mechanical ventilation (MV) maintains gas exchange in patients with ARDS but exposes lung cells to physical forces that exacerbate injury. Our data demonstrate that mTOR complex 1 (mTORC1) is a mechanosensor in lung epithelial cells and that activation of this pathway during MV impairs lung function.

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Background And Aims: High Protein diets may be associated with endocrine responses that favor improved metabolic outcomes. We studied the response to High Protein (HP) versus High Carbohydrate (HC) Diets in terms of incretin hormones GLP-1 and GIP, the hunger hormone ghrelin and BNP, which is associated with cardiac function. We hypothesized that HP diets induce more pronounced release of glucose lowering hormones, suppress hunger and improve cardiac function.

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Mechanical ventilation generates injurious forces that exacerbate lung injury. These forces disrupt lung barrier integrity, trigger proinflammatory mediator release, and differentially regulate genes and non-coding oligonucleotides including microRNAs. In this study, we identify miR-146a as a mechanosensitive microRNA in alveolar macrophages that has therapeutic potential to mitigate lung injury during mechanical ventilation.

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Acute respiratory distress syndrome (ARDS) is an inflammatory lung disease with a high morbidity and mortality rate, for which no pharmacologic treatment is currently available. Our previous studies discovered that a pivotal step in the disease process is the activation of the nuclear factor of activated T cells (NFAT) c3 in lung macrophages, suggesting that inhibitors against the upstream protein phosphatase calcineurin should be effective for prevention/treatment of ARDS. Herein, we report the development of a highly potent, cell-permeable, and metabolically stable peptidyl inhibitor, CNI103, which selectively blocks the interaction between calcineurin and NFATc3, through computational and medicinal chemistry.

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Pulmonary macrophages play a critical role in the recognition of pathogens, initiation of host defense via inflammation, clearance of pathogens from the airways, and resolution of inflammation. Recently, we have shown a pivotal role for the nuclear factor of activated T-cell cytoplasmic member 3 (NFATc3) transcription factor in modulating pulmonary macrophage function in LPS-induced acute lung injury (ALI) pathogenesis. Although the NFATc proteins are activated primarily by calcineurin-dependent dephosphorylation, here we show that LPS induces posttranslational modification of NFATc3 by polyADP-ribose polymerase 1 (PARP-1)-mediated polyADP-ribosylation.

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Objectives: This report provides analyses and perspective of a survey of critical care workforce, workload, and burnout among the intensivists and advanced practice providers of established U.S. and Canadian critical care organizations and provides a research agenda.

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