ITK regulates antigen-specific CD8+ T cell-derived IL-10 production and modulates influenza-induced pulmonary immunopathology

Influenza (flu) infection is a leading cause of respiratory disease and death worldwide, causing 3-5 million cases of severe illness and more than 250,000 deaths during an average flu season. Severe life-threatening influenza infections in humans are accompanied by an aggressive pro-inflammatory response and an insufficient anti-inflammatory immunity. The production of the immunosuppressive cytokine IL-10 by virus-specific T cells is critical in limiting the immunopathology during flu infection, however, our understanding of how this immunomodulatory event is regulated at the molecular level is very limited. Using mouse models that report the production of IL-10 through green fluorescent protein, OTI CD8+ T cells and influenza A viruses that express the OTI antigen ovalbumin (OVA), we find that the T cell receptor (TCR) responsive tyrosine kinase, Interleukin-2 Inducible T cell kinase (ITK), is a critical regulator of the ability of CD8+ T cells to develop into IL-10-producing cells in an antigen specific manner. The absence of ITK resulted in increased morbidity and mortality in murine model post influenza A infection, accompanied by a severe impairment of IL-10 production by CD8+ T cells in the airway. ITK kinase activity is required for its role in promoting IL-10-producing CD8+ T cell differentiation, by regulating the levels of expression of transcription factors including IRF4, Blimp1, AHR and cMAF. Our data suggest that ITK regulates CD8+ T cell production of IL-10 during influenza A infection, and modulates the development of pulmonary immunopathology. Targeting ITK signaling maybe a promising strategy in modulating airway inflammation during viral infections.

The role of tyrosine kinase Itk in T helper 17 and T regulatory cells in IL17 mediated hypersensitivity pneumonitis

The balance of inflammatory and suppressive cytokines is critical in controlling inflammatory responses, and the pro- and anti-inflammatory cytokines IL17A and IL10 has been implicated in numerous pulmonary inflammatory diseases. The tyrosine kinase, Itk, plays a critical role in T cell activation. We have previously shown that Itk−/− mice do not develop allergic airway disease coupled with reduced production of IL17A in the lungs. In vitro, Itk is required for the development of Th17 cells and their production of the pro-inflammatory cytokine IL17A. Furthermore, Type I regulatory and Foxp3+ T regulatory (Tregs) cells, suppressive producers of IL10, are positively and negatively regulated by Itk respectively. Farmer’s lung is a subset of hypersensitivity pneumonitis caused by repeated exposure to the bacteria Saccharopolyspora rectivirgula (SR), and is dependent on IL17A and regulated by IL10. We find that surprisingly, exposure to SR drives robust IL17A response produced by CD4+ T cells even in the absence of Itk, accompanied by the development of pulmonary inflammation. SR also induced Itk independent development of a population of population of Foxp3+ Tregs cells that produce IL17A, accompanied by a significant decrease in Tr1 cells compared to WT mice. These studies suggest that TCR signaling through Itk differentially regulates the development of inflammatory Th17 cells and suppressive Tregs and Tr1 cells. Understanding how Itk modulates the development of Th17/Treg cytokine responses will allow us to better understand the precise role of Itk in the production of IL17A and IL10 in airway inflammation.

Ex vivo synthetic immune tissues with T cell signals for differentiating antigen-specific, high affinity germinal center B cells

Most antigen discovery and vaccine development aimed at driving functional B cell responses rely on mouse immunizations studies. To date, there is no 3D ex vivo immune tissues, which are capable of driving antigen-specific B cell responses to rapidly determine the humoral immunogenicity of antigens, understand the role of extracellular matrix in humoral immunity, and generate high affinity antibody responses. This can be attributed to the complexity of B cell differentiation and affinity maturation process in the germinal center (GC) reaction, which makes these highly specialized cells susceptible to rapid apoptosis ex vivo. We have previously reported immune tissues that show ex vivo GC-like response, however in a non-antigen specific manner. Here, we report a maleimide (MAL)-functionalized polyethylene glycol (PEG)-based designer immune tissues that modulate B cell differentiation and enriches antigen-specific GC B cells in the presence of T-cell like signals. With the 3D synthetic immune tissue platform, we assessed various hydrogel design parameters to control ex vivo GC reaction. Using an Ezh2fl/fl Cγ1-cre transgenic mouse model, we demonstrated ex vivo IgG1 antibody class switching. Using immune tissues developed from a B1-8hi mutant mouse that represents a recombined antibody variable region derived from a 4-hydroxy-3-nitrophenylacetyl (NP) hapten binding antibody (B1-8), we demonstrate antigen specificity and selective enrichment of antigen-specific B cells with high affinity at both cell surface and secreted levels in integrin ligand-dependent manner. The ex vivo antigen-specific platform technology offers use in scientific understanding of immunobiology, matrix immunology, and in biotechnology applications, ranging from the antigen testing, vaccine development, and generation of antibodies against diseases.

Thymic regulatory T cells arise via two distinct developmental programs

The developmental programs that generate a broad repertoire of regulatory T cells (T_reg cells) able to respond to both self antigens and non-self antigens remain unclear. Here we found that mature T_reg cells were generated through two distinct developmental programs involving CD25⁺ T_reg cell progenitors (CD25⁺ T_regP cells) and Foxp3^lo T_reg cell progenitors (Foxp3^lo T_regP cells). CD25⁺ T_regP cells showed higher rates of apoptosis and interacted with thymic self antigens with higher affinity than did Foxp3^lo T_regP cells, and had a T cell antigen receptor repertoire and transcriptome distinct from that of Foxp3^lo T_regP cells. The development of both CD25⁺ T_regP cells and Foxp3^lo T_regP cells was controlled by distinct signaling pathways and enhancers. Transcriptomics and histocytometric data suggested that CD25⁺ T_regP cells and Foxp3^lo T_regP cells arose by coopting negative-selection programs and positive-selection programs, respectively. T_reg cells derived from CD25⁺ T_regP cells, but not those derived from Foxp3^lo T_regP cells, prevented experimental autoimmune encephalitis. Our findings indicate that T_reg cells arise through two distinct developmental programs that are both required for a comprehensive T_reg cell repertoire capable of establishing immunotolerance.

Beyond Type 1 Regulatory T Cells: Co-expression of LAG3 and CD49b in IL-10-Producing T Cell Lineages

Type 1 regulatory CD4⁺ T (Tr1) cells express high levels of the immunosuppressive cytokine IL-10 but not the master transcription factor Foxp3, and can suppress inflammation and promote immune tolerance. In order to identify and obtain viable Tr1 cells for research and clinical applications, co-expression of CD49b and LAG3 has been proposed as a unique surface signature for both human and mouse Tr1 cells. However, recent studies have revealed that this pattern of co-expression is dependent on the stimulating conditions and the differentiation stage of the CD4⁺ T cells. Here, using an IL-10^GFP/Foxp3^RFP dual reporter transgenic murine model, we demonstrate that co-expression of CD49b and LAG3 is not restricted to the Foxp3⁻ Tr1 cells, but is also observed in Foxp3⁺ T regulatory (Treg) cells and CD8⁺ T cells that produce IL-10. Our data indicate that IL-10-producing Tr1 cells, Treg cells and CD8⁺ T cells are all capable of co-expressing LAG3 and CD49b in vitro following differentiation under IL-10-inducing conditions, and in vivo following pathogenic insult or infection in the pulmonary mucosa. Our findings urge caution in the use of LAG3/CD49b co-expression as sole markers to identify Tr1 cells, since it may mark IL-10-producing T cell lineages more broadly, including the Foxp3⁻ Tr1 cells, Foxp3⁺ Treg cells, and CD8⁺ T cells.

Asthma Induction During Development and Adult Lung Function, Behavior and Brain Gene Expression

In developing youth, allergic asthma is the most common chronic condition, with 9%–10% of youth affected. Asthma onset during childhood and adolescence is further associated with other health issues, particularly psychiatric conditions. To understand causal mechanisms by which developmental asthma may lead to altered behavior, brain and health trajectories, we developed a mouse model of developmental allergic asthma. In the current study, we tested for potential long-term effects of developmental asthma on adult lung function and behavior and brain gene expression associated with emotion and stress regulation. We manipulated airway inflammation (AI) and methacholine (MCH)-induced bronchospasm (resulting in labored breathing, LB) in young male and female BALB/cJ mice and measured adult outcomes 3 months after final asthma manipulations. Results indicated that allergen exposure, used to cause AI, and which ended on post-natal day 56 (P56), led to persistent lung AI, mucus buildup and gene expression related to allergic asthma 3 months after final allergen exposure. In addition, at this same age, early allergen exposure led to altered brain gene expression related to stress regulation (prefrontal corticotropin releasing hormone receptor 1, Crhr1 and hippocampal glucocorticoid receptor, GR) and serotonin function (brainstem serotonin transporter, SERT). On the other hand, LB events during development led to altered anxiety-related behavior. Importantly, sex and pre-asthma fear-related behavior (ultrasonic vocalization, USV rates) modulated these adult outcomes. Asthma that develops during childhood/adolescence may have long-term impacts on emotion and stress regulation mechanisms, and these influences may be moderated by sex and pre-asthma temperament.

Factors Contributing to the Success of NIH-Designated Underrepresented Minorities in Academic and Nonacademic Research Positions

We report the outcomes of a survey of underrepresented minorities (URMs) in life science academic (e.g., faculty) and nonacademic (e.g., research-related) positions seeking to ascertain variables that contribute to their success (e.g., favorable or desired outcome). Given that they had positions in research careers, all respondents were presumed to be successful, and we sought to identify shared factors that were associated with this success. As in previous studies, respondents reported that undergraduate research opportunities, performing research in small- to medium-sized laboratories, and access to mentors throughout all stages of training were important factors for success in their careers. Surprisingly, analysis of the survey results suggests that a record of publications in high-impact factor journals was not essential for their success. There were fundamental differences in the experiences and needs of URMs in academic and nonacademic careers. For example, academic URMs ranked having mentorship as their first choice in order of importance compared with the nonacademic respondents, who ranked this category as their fifth selection. These findings suggest that taking diverse approaches toward these groups is critical for ensuring that all of the most creative minds have an equal opportunity to contribute to realizing our national research goals and diversified workforce.

The TCR/ITK signaling pathway regulates the counterbalance of effector and regulatory T cell development

The mammalian immune system has evolved both effector and regulatory immune axes, and T cells are the key players in both arms. The immune system sorts, responds to and clears invading pathogens through pro-inflammatory activity, which can cause damage to the affected tissues, and eventually have to be resolved to allow tissue remodeling and resume physiological homeostasis. The balance between pro-inflammatory and suppressive immune functions are critical for host health and survival. The T cell antigen receptor (TCR) signals through the downstream non-receptor interleukin-2 inducible T cell kinase (ITK), which is a key signaling modulator of T cell development, differentiation, activation and function. We find that in the face of different inflammatory and nutritional conditions, the TCR/ITK signaling pathway fine-tunes the balance between effector and regulatory T cell development, such as the ratio between Th17/Treg and Th1/Tr1 cells. This balance is regulated by the TCR/ITK signaling via differential downstream signals and metabolic programs. While ITK is not required for T cell activation, it functions as a rheostat of the TCR to regulate signal strength in response to extracellular antigens, and may be a target to allow therapeutically manipulating the balance between effector and regulatory immunity, dependent on the disease conditions.

Amino acid starvation sensing dampens IL-1β production by activating riboclustering and autophagy

Activation of the amino acid starvation response (AAR) increases lifespan and acute stress resistance as well as regulates inflammation. However, the underlying mechanisms remain unclear. Here, we show that activation of AAR pharmacologically by Halofuginone (HF) significantly inhibits production of the proinflammatory cytokine interleukin 1β (IL-1β) and provides protection from intestinal inflammation in mice. HF inhibits IL-1β through general control nonderepressible 2 kinase (GCN2)–dependent activation of the cytoprotective integrated stress response (ISR) pathway, resulting in rerouting of IL-1β mRNA from translationally active polysomes to inactive ribocluster complexes—such as stress granules (SGs)—via recruitment of RNA-binding proteins (RBPs) T cell–restricted intracellular antigen-1(TIA-1)/TIA-1–related (TIAR), which are further cleared through induction of autophagy. GCN2 ablation resulted in reduced autophagy and SG formation, which is inversely correlated with IL-1β production. Furthermore, HF diminishes inflammasome activation through suppression of reactive oxygen species (ROS) production. Our study unveils a novel mechanism by which IL-1β is regulated by AAR and further suggests that administration of HF might offer an effective therapeutic intervention against inflammatory diseases.

Reduced intake of food (also known as dietary restriction) without malnutrition has been shown to benefit health in humans and animals, including an increase in life expectancy, metabolic fitness, and resistance to acute stress. Recent studies have attributed the benefits associated with dietary restriction to the reduced intake of amino acids. However, the underlying mechanisms through which amino acid restriction regulates various homeostatic processes are poorly defined. Here, we show that activation of amino acid starvation response (AAR) by the small molecule Halofuginone (HF) results in a significant inhibition of production of interleukin 1β (IL-1β), a proinflammatory mediator. We find that AAR provides protection from intestinal inflammation–associated pathology in a mouse model of colitis through a novel mechanism involving the formation of riboclusters (groups of RNA-binding proteins (RBPs) and stalled mRNA complexes) and autophagy. We further show that HF-mediated inhibition in IL-1β production is dependent on general control nonderepressible 2 kinase (GCN2), an amino acid deprivation sensor. This study provides the mechanisms regulating AAR-induced benefits in the context of inflammation and further suggests that the administration of HF might offer an effective therapeutic intervention against inflammatory diseases in mammals.

ITK signalling via the Ras/IRF4 pathway regulates the development and function of Tr1 cells

Type 1 regulatory T (Tr1) cells differentiate in response to signals engaging the T cell receptor (TCR), express high levels of the immunosuppressive cytokine IL-10, but not Foxp3, and can suppress inflammation and promote immune tolerance. Here we show that ITK, an important modulator of TCR signalling, is required for the TCR-induced development of Tr1 cells in various organs, and in the mucosal system during parasitic and viral infections. ITK kinase activity is required for mouse and human Tr1 cell differentiation. Tr1 cell development and suppressive function of Itk deficient cells can be restored by the expression of the transcription factor interferon regulatory factor 4 (IRF4). Downstream of ITK, Ras activity is responsible for Tr1 cell induction, as expression of constitutively active HRas rescues IRF4 expression and Tr1 cell differentiation in Itk-/- cells. We conclude that TCR/ITK signalling through the Ras/IRF4 pathway is required for functional development of Tr1 cells.

Itk: A potential target for Saccharopolyspora rectivirgula-induced hypersensitivity pneumonitis

Hypersensitivity pneumonitis (HP) is a lung disease caused by repeated inhalation of environmental antigens leading to inflammation, tissue scarring, and impaired lung function. This pathology is associated with IL-17A-producing Th17 cells and recruitment of inflammatory cells such as neutrophils to the lungs; on the other hand, Foxp3+ regulatory T (Treg) cells play a protective rolein HP by suppressing pathogenic T cell functions. The thermophile Saccharopolyspora rectivirgula (SR) causes HP in humans, attributed to the rare farmers’ lung disease. We used a murine model carrying the IL-17AGFP/Foxp3RFP dual reporters in SR-induced HP, to study the cellular and molecular mechanisms of HP disease development. IL-2-inducible T cell Kinase, ITK is downstream of the T cell receptor, and is required for effective differentiation of Th17 cells, but limits the expansion of Treg cells. In this work, we sought to determine the possibility of using ITK as a target for pharmaceutical inhibitors in HP. To evaluate the effect of targeting ITK kinase activity in HP therapy, we utilized an Itk allele sensitive mutant (Itkas) that allows specific inhibition by a compound 3MBPP1. WT, Itk−/− and ItkasIL-17AGFP/Foxp3RFP mice exposed to SR were treated with 3MBPP and analyzed for histopathology and various immune cell populations. Intranasal delivery of 3MBPP1 for up to 4 weeks affected pathogenesis and targeted primarily the bronchoalveolarlavage (BAL) immune subsets, including CD4+ IL-17A+ cells. In addition, Treg cells in the pulmonary lymph nodes, neutrophils in the lungs, and γδ T cells in all organs were affected by the treatment. These data suggest that ITK may be a therapeutic target for HP that involves the IL-17 and Foxp3-expressing T cell subsets.

TCR signal strength and antigen affinity modulate CD8+ memory T Cell development

CD8+ T cells play a critical role in adaptive immunity by maintaining the ability to differentiate into CD8+ memory T cells. During an intracellular infection, CD8+ T cells pass through several characteristic phases before becoming mature memory cells. Initial antigen stimulation causes naïve CD8+ T cells to clonally expand and differentiate into short-lived effector cells (SLECs). Subsequently, SLECs undergo a contraction phase to give rise to memory precursor effector cells (MPECs); 5–10% of these MPECs survive the initial contraction phase from SLECs to further develop into CD8+ memory T cells. We have shown that the non-receptor tyrosine kinase Itk, which regulates TCR signal strength, can significantly suppress CD8+ memory T cell development. We hypothesize from that TCR signal strength may function synergistically with antigen affinity to regulate development of memory CD8+ T cells. We are testing this hypothesis using Itk deficient OT-1 TCR transgenic mice, in which CD8+ T cells are engineered to be specific for the Ovalbumin (Ova) protein but exhibit reduced TCR signaling, adoptive transfer of donor naïve CD8+ T cells into marked recipient mice, followed by an infection with recombinant Listeria monocytogenes expressing Ova peptide variant epitopes for CD8+ T cells. Using this model, we can quantitatively determine how TCR signal strength intersects with TCR affinity to control memory development. Our findings suggest that TCR signal strength and TCR affinity separately regulate CD8+ memory development. This data holds societal impact and promise for the advancement of rational vaccine development.

ITK signaling via the Ras/IRF4 pathway regulates the development and function of type 1 regulatory T cells

Type 1 regulatory T (Tr1) cells differentiate in response to signals engaging T cell receptor (TCR), express high levels of the immunosuppressive cytokine IL-10 but not Foxp3, and can suppress inflammation and promote immune tolerance. Here, using IL-10GFP/Foxp3RFP dual reporter transgenic mouse system, we show that ITK, a key modulator of TCR signaling, is required for the development of Tr1 cells in various organs following TCR activation, and in the mucosal system during parasitic and viral infections. ITK kinase activity is required for mouse and human Tr1 cell fate programming and regulates the balance between IL-10 and IFN-γ production during Tr1 cell differentiation. The requirement for ITK function during Tr1 cell development and suppressive function can be restored by the expression of the transcription factor IRF4. Downstream of ITK, Ras, and MAP kinases ERK1/2, p38 and JNK, are required for Tr1 cell differentiation, but not Th17 cell differentiation. We have previously shown that Th17 differentiation is also dependent on ITK signaling. However, in the absence of ITK, expression of the constitutively active HRasG12V rescued IRF4 expression and Tr1 cell differentiation, but failed to restore Th17 cell differentiation. We conclude that the TCR/ITK signaling through the Ras/MAPK/IRF4 pathway is specifically required for functional development of Tr1 cells, and that targeting these signaling components may be of therapeutic benefit.

Itk independent development of natural Th17 cells and IL17A-driven hypersensitivity pneumonitis

The tyrosine kinase, Itk, plays a critical role in T cell receptor signaling, and we have previously shown that Itk is required for the development of Th17 cells and their production of the pro-inflammatory cytokine IL17A. IL17A has been implicated in numerous pulmonary inflammatory diseases. We have previously shown that Itk−/− mice do not develop allergic airway disease coupled with protected reduced production of IL17A in the lungs in a model of allergic asthma. Farmer’s lung is a subset of hypersensitivity pneumonitis caused by repeated exposure to the bacteria Saccharopolyspora rectivirgula (SR). This IL17A-driven disease is characterized by an influx of neutrophils and T lymphocytes. Here we show that a population of natural Th17 cell develop in the absence of Itk. Furthermore, exposure to SR drives robust IL17A response produced by CD4+ T cells even in the absence of Itk, accompanied by the development of pulmonary inflammation. These studies suggest that TCR signaling through Itk differentially regulates the development of conventional and natural Th17 cells. Understanding how Itk modulates the Th17 cytokine responses will allow us to better understand the precise role of Itk in the production of IL17A in airway inflammation.

The decidua of preeclamptic-like BPH/5 mice exhibits an exaggerated inflammatory response during early pregnancy

Preeclampsia is a devastating complication of pregnancy characterized by late-gestation hypertension and proteinuria. Because the only definitive treatment is delivery of the fetus and placenta, preeclampsia contributes to increased morbidity and mortality of both mother and fetus. The BPH/5 mouse model, which spontaneously develops a syndrome strikingly similar to preeclampsia, displays excessive inflammation and suppression of inflammation improves pregnancy outcomes. During early pregnancy, decidual macrophages play an important role in promoting maternal tolerance to fetal antigens and regulating tissue remodeling, two functions that are critical for normal placental development. BPH/5 pregnancies are characterized by abnormal placentation; therefore, we hypothesized that macrophage localization and/or function is altered during early pregnancy at the site of placental formation (the decidua) compared to C57BL/6 controls. At early gestation time points, before the onset of maternal hypertension or proteinuria, there was a reduction in the number of macrophages in BPH/5 decidua and a concomitant increase in activated T cells compared with C57BL/6. BPH/5 decidua also exhibited decreased expression of the immunosuppressive cytokine, IL-10, and increased expression of pro-inflammatory, inducible nitric oxide synthase. Together, these data suggest that a reduction in decidual macrophages during pregnancy is associated with immune activation in BPH/5 mice, inadequate placental development and may contribute to adverse pregnancy outcomes in this model.

Self-Assembly Protein Nanogels for Safer Cancer Immunotherapy

Soluble antigen-based cancer vaccines have poor retention in tissues along with suboptimal antigen processing by dendritic cells. Multiple booster doses are often needed, leading to dose-limiting systemic toxicity. A versatile, immunomodulatory, self-assembly protein nanogel vaccine is reported that induces robust immune cell response at lower antigen doses than soluble antigens, an important step towards biomaterials-based safer immunotherapy approaches.

The non-receptor tyrosine kinase ITK is required for type 1 regulatory T cell development

Type 1 regulatory T (Tr1)cells lack the expression of Foxp3 but are potent producers of the immunosuppressive cytokine IL-10, with profound regulatory function in suppressing inflammation and promoting tolerance. Tr1 cells differentiate in response to signals engaging T cell receptor (TCR) and/or regulatory cytokine milieu. The non-receptor tyrosine kinase ITK is a key modulator downstream of TCR, playing critical role in T cell development and function. Using mouse models carrying Foxp3-RFP and IL-10-GFP dual reporters, we found that, in the absence of ITK, Foxp3− IL-10+ Tr1 cell development driven by TCR activation is severely impaired in various tissues (spleen, lymph nodes, lung, gut, and fat). Under Tr1 polarizing condition, naïve Foxp3− CD4+T cells isolated from WT mouse thymus and spleen can both give rise to Tr1cells, however, Itk−/− thymic and splenic naïve Foxp3− CD4+ T cells are deficient in Tr1 differentiation. Although Itk−/−CD4+ T cells proliferated under Tr1 differentiating conditions, they failed to up-regulate LAG3, CD49b, ICOS, PD-1, c-Maf, AHR, and IRF4 to levels observed in WT cells, suggesting that ITK is critical for Tr1 cell fate programming. Utilizing transgenic mouse model carrying an allele sensitive mutant of ITK that allows ITK kinase specific blockade by a small molecule 3MB-PP1, we also determined that the expression of the aforementioned markers is dependent on ITK kinas activity. Inhibiting ITK kinase activity also diminished Tr1 differentiation inhuman CD4+ T cells. We conclude that ITK is required for Tr1 cell development and targeting ITK signaling may be a strategy to modulate regulatory immunity for clinical benefit.

Post-transcriptional Regulation of Immunological Responses through Riboclustering

Immunological programing of immune cells varies in response to changing environmental signals. This process is facilitated by modifiers that regulate the translational fate of mRNAs encoding various immune mediators, including cytokines and chemokines, which in turn determine the rapid activation, tolerance, and plasticity of the immune system. RNA-binding proteins (RBPs) recruited by the specific sequence elements in mRNA transcripts are one such modifiers. These RBPs form RBP-RNA complexes known as "riboclusters." These riboclusters serve as RNA sorting machinery, where depending upon the composition of the ribocluster, translation, degradation, or storage of mRNA is controlled. Recent findings suggest that this regulation of mRNA homeostasis is critical for controlling the immune response. Here, we present the current knowledge of the ribocluster-mediated post-transcriptional regulation of immune mediators and highlight recent findings regarding their implications for the pathogenesis of acute or chronic inflammatory diseases.

Role(s) of IL-2 inducible T cell kinase and Bruton's tyrosine kinase in mast cell response to lipopolysaccharide

Mast cells play critical roles during immune responses to the bacterial endotoxin lipopolysaccharide (LPS) that can lead to fatal septic hypothermia [1], [2], [3]. IL-2 inducible T cell kinase (ITK) and Bruton's tyrosine kinase (BTK) are non-receptor tyrosine kinases that act downstream of numerous receptors, and have been shown to modulate mast cell responses downstream of FcεRIα [4], however, their roles in regulating mast cell responses to endotoxic stimuli were unclear. We found that the absence of ITK and BTK alters the mast cell response to LPS, and leads to enhanced pro-inflammatory cytokine production by mast cells and more severe LPS-induced hypothermia in mice [5]. Here, we detail our investigation using microarray analysis to study the transcriptomic profiles of mast cell responses to LPS, and the roles of ITK and/or BTK expression in this process. Mouse whole genome array data of WT, Itk (-/-) , Btk (-/-) , and Itk (-/-)  Btk (-/-) bone marrow-derived mast cells (BMMCs) stimulated by PBS (control) or LPS for 1 h were used in our latest research article [5] and is available in the Gene Expression Omnibus under accession number GSE64287.

Circulating microRNAs as biomarkers in patients with allergic rhinitis and asthma

BACKGROUND

MicroRNAs (miRNAs) are emerging as important regulatory molecules that might be involved in the pathogenesis of various diseases. Circulating miRNAs might be noninvasive biomarkers to diagnose and characterize asthma and allergic rhinitis (AR).

OBJECTIVE

We sought to determine whether miRNAs are differentially expressed in the blood of asthmatic patients compared with those in the blood of nonasthmatic patients with AR and nonallergic nonasthmatic subjects. Furthermore, we sought to establish whether miRNAs could be used to characterize or subtype asthmatic patients.

METHODS

Expression of plasma miRNAs was measured by using real-time quantitative PCR in 35 asthmatic patients, 25 nonasthmatic patients with AR, and 19 nonallergic nonasthmatic subjects. Differentially expressed miRNAs were identified by using Kruskal-Wallis 1-way ANOVA with Bonferroni P value adjustment to correct for multiple comparisons. A random forest classification algorithm combined with a leave-one-out cross-validation approach was implemented to assess the predictive capacities of the profiled miRNAs.

RESULTS

We identified 30 miRNAs that were differentially expressed among healthy, allergic, and asthmatic subjects. These miRNAs fit into 5 different expression pattern groups. Among asthmatic patients, miRNA expression profiles identified 2 subtypes that differed by high or low peripheral eosinophil levels. Circulating miR-125b, miR-16, miR-299-5p, miR-126, miR-206, and miR-133b levels were most predictive of allergic and asthmatic status.

CONCLUSIONS

Subsets of circulating miRNAs are uniquely expressed in patients with AR and asthmatic patients and have potential for use as noninvasive biomarkers to diagnose and characterize these diseases.

Nonreceptor tyrosine kinases ITK and BTK negatively regulate mast cell proinflammatory responses to lipopolysaccharide

BACKGROUND

Mast cells are indispensable for LPS-induced septic hypothermia, in which TNF-α plays an essential role to initiate septic responses. ITK and BTK regulate mast cell responses to allergens, but their roles in mast cell responses in LPS-induced sepsis are unclear.

OBJECTIVE

We sought to investigate the roles of ITK and BTK in mast cell responses during LPS-induced septic inflammation.

METHODS

Mice (genetically modified or bone marrow-derived mast cell-reconstituted Sash) were given LPS to induce septic hypothermia in the presence or absence of indicated inhibitors. Flow cytometry was used to determine LPS-induced cell influx and TNF-α production in peritoneal cells. Microarray was used for genomewide gene expression analysis on bone marrow-derived mast cells. Quantitative PCR and multiplex were used to determine transcribed and secreted proinflammatory cytokines. Microscopy and Western blotting were used to determine activation of signal transduction pathways.

RESULTS

The absence of ITK and BTK leads to exacerbation of LPS-induced septic hypothermia and neutrophil influx. Itk(-/-)Btk(-/-) mast cells exhibit hyperactive preformed and LPS-induced TNF-α production, and lead to more severe LPS-induced septic hypothermia when reconstituted into mast cell-deficient Sash mice. LPS-induced nuclear factor kappa B, Akt, and p38 activation is enhanced in Itk(-/-)Btk(-/-) mast cells, and blockage of phosphatidylinositol-4,5-bisphosphate 3-kinase, Akt, or p38 downstream mitogen-activated protein kinase interacting serine/threonine kinase 1 activation significantly suppresses TNF-α hyperproduction and attenuates septic hypothermia.

CONCLUSIONS

ITK and BTK regulate thermal homeostasis during septic response through mast cell function in mice. They share regulatory function downstream of Toll-like receptor 4/LPS in mast cells, through regulating the activation of canonical nuclear factor kappa B, phosphatidylinositol-4,5-bisphosphate 3-kinase/Akt, and p38 signaling pathways.

The origin and implementation of the Broadening Experiences in Scientific Training programs: an NIH common fund initiative

Recent national reports and commentaries on the current status and needs of the U.S. biomedical research workforce have highlighted the limited career development opportunities for predoctoral and postdoctoral trainees in academia, yet little attention is paid to preparation for career pathways outside of the traditional faculty path. Recognizing this issue, in 2013, the U.S. National Institutes of Health (NIH) Common Fund issued a request for application titled "NIH Director's Biomedical Research Workforce Innovation Award: Broadening Experiences in Scientific Training (BEST)." These 5-yr 1-time grants, awarded to 17 single or partnering institutions, were designed to develop sustainable approaches to broaden graduate and postgraduate training, aimed at creating training programs that reflect the range of career options that trainees may ultimately pursue. These institutions have formed a consortium in order to work together to develop, evaluate, share, and disseminate best practices and challenges. This is a first report on the early experiences of the consortium and the scope of participating BEST programs. In this report, we describe the state of the U.S. biomedical workforce and development of the BEST award, variations of programmatic approaches to assist with program design without BEST funding, and novel approaches to engage faculty in career development programs. To test the effectiveness of these BEST programs, external evaluators will assess their outcomes not only over the 5 yr grant period but also for an additional 10 yr beyond award completion.