Chromatin modifier Hmga2 promotes adult hematopoietic stem cell function and blood regeneration in stress conditions.

The molecular mechanisms governing the response of hematopoietic stem cells (HSCs) to stress insults remain poorly defined. Here, we investigated effects of conditional knock-out or overexpression of Hmga2 (High mobility group AT-hook 2), a transcriptional activator of stem cell genes in fetal HSCs. While Hmga2 overexpression did not affect adult hematopoiesis under homeostasis, it accelerated HSC expansion in response to injection with 5-fluorouracil (5-FU) or in vitro treatment with TNF-α. In contrast, HSC and megakaryocyte progenitor cell numbers were decreased in Hmga2 KO animals. Transcription of inflammatory genes was repressed in Hmga2-overexpressing mice injected with 5-FU, and Hmga2 bound to distinct regions and chromatin accessibility was decreased in HSCs upon stress. Mechanistically, we found that casein kinase 2 (CK2) phosphorylates the Hmga2 acidic domain, promoting its access and binding to chromatin, transcription of anti-inflammatory target genes, and the expansion of HSCs under stress conditions. Notably, the identified stress-regulated Hmga2 gene signature is activated in hematopoietic stem progenitor cells of human myelodysplastic syndrome patients. In sum, these results reveal a TNF-α/CK2/phospho-Hmga2 axis controlling adult stress hematopoiesis.

Identification of exhaled volatile organic compounds that characterize asthma phenotypes: A J-VOCSA study.

BACKGROUND: Asthma is characterized by phenotypes of different clinical, demographic, and pathological characteristics. Identifying the profile of exhaled volatile organic compounds (VOCs) in asthma phenotypes may facilitate establishing biomarkers and understanding asthma background pathogenesis. This study aimed to identify exhaled VOCs that characterize severe asthma phenotypes among patients with asthma. METHODS: This was a multicenter cross-sectional study of patients with severe asthma in Japan. Clinical data were obtained from medical records, and questionnaires were collected. Exhaled breath was sampled and subjected to thermal desorption gas chromatography-mass spectrometry (GC/MS). RESULTS: Using the decision tree established in the previous nationwide asthma cohort study, 245 patients with asthma were divided into five phenotypes and subjected to exhaled VOC analysis with 50 healthy controls (HCs). GC/MS detected 243 VOCs in exhaled breath samples, and 142 frequently detected VOCs (50% of all samples) were used for statistical analyses. Cluster analysis assigning the groups with similar VOC profile patterns showed the highest similarities between phenotypes 3 and 4 (early-onset asthma phenotypes), followed by the similarities between phenotypes 1 and 2 (late-onset asthma phenotypes). Comparisons between phenotypes 1-5 and HC revealed 19 VOCs, in which only methanesulfonic anhydride showed p < 0.05 adjusted by false discovery rate (FDR). Comparison of these phenotypes yielded several VOCs showing different trends (p < 0.05); however, no VOCs showed p < 0.05 adjusted by FDR. CONCLUSIONS: Exhaled VOC profiles may be useful for distinguishing asthma and asthma phenotypes; however, these findings need to be validated, and their pathological roles should be clarified.

[THE EFFICACY OF BRONCHIAL THERMOPLASTY IN LONG-TERM MAINTENANCE OF ADULT PATIENTS WITH MODERATE TO SEVERE ASTHMA].

BACKGROUND AND AIMS: Bronchial thermoplasty (BT) is a bronchoscopic treatment for adult patients with moderate to severe asthma. A systematic review was conducted to examine the efficacy of this treatment. METHODS: Randomized controlled comparing BT to a control in adult patients with moderate to severe asthma were added to the previously conducted systematic review. Literature published prior to July 2022 was selected. RESULTS: Four trials were included in this study. BT resulted in significant improvement in quality of life. However, no significant difference in asthma control was observed. Moreover, the incidence of severe adverse events during the treatment period was increased by BT. Furthermore, BT did not improve lung function, increase withdrawal from oral corticosteroids, reduce frequency of rescue medication usage, or increase the number of symptom-free days. CONCLUSION: From a risk-benefit perspective, there is insufficient evidence to support a recommendation of BT in adult patients with moderate to severe asthma.

HMGN3 represses transcription of epithelial regulators to promote migration of cholangiocarcinoma in a SNAI2-dependent manner.

High mobility group nucleosome-binding protein 3 (HMGN3), a member of the HMGN family, modulates the structure of chromatin and regulates transcription through transcription factors. HMGN3 has been implicated in the development of various cancers; however, the underlying mechanisms remain unclear. We herein demonstrated that the high expression of HMGN3 correlated with the metastasis of liver fluke infection-induced cholangiocarcinoma (CCA) in patients in northeastern Thailand. The knockdown of HMGN3 in CCA cells significantly impaired the oncogenic properties of colony formation, migration, and invasion. HMGN3 inhibited the expression of and blocked the intracellular polarities of epithelial regulator genes, such as the CDH1/E-cadherin and TJAP1 genes in CCA cells. A chromatin immunoprecipitation sequencing analysis revealed that HMGN3 required the transcription factor SNAI2 to bind to and repress the expression of epithelial regulator genes, at least in part, due to histone deacetylases (HDACs), the pharmacological inhibition of which reactivated these epithelial regulators in CCA, leading to impairing the cell migration capacity. Therefore, the overexpression of HMGN3 represses the transcription of and blocks the polarities of epithelial regulators in CCA cells in a manner that is dependent on the SNAI2 gene and HDACs.

A case of acute kidney injury due to native kidney BK polyomavirus-associated nephropathy in a human T-lymphotropic virus type 1 carrier.

BACKGROUND: BK polyomavirus-associated nephropathy (BKPyVAN) has become a major cause of kidney dysfunction and graft loss in kidney transplant recipients. On rare occasion, polyomavirus has also been known to affect native kidneys of immunocompromised individuals. Only a small number of opportunistic infections have been reported in the carrier phase of human T-lymphotropic virus type 1 (HTLV-1). This is the first reported case of BKPyVAN in native kidneys of an HTLV-1 carrier. CASE PRESENTATION: A 61-year-old man was referred to our hospital from a primary care physician for work-up and treatment of pneumonia. He was diagnosed with Pneumocystis pneumonia and identified as a HTLV-1 carrier who had not yet developed adult T-cell leukemia (ATL). The pneumonia was successfully treated with sulfamethoxazole-trimethoprim. He had never been diagnosed with any kind of kidney dysfunction. Laboratory investigations showed a serum creatinine of 5.3 mg/dL, and urinary sediment showed cells with nuclear enlargement and inclusion bodies suggesting viral infection. The urinary Papanicolaou stain showed inclusions in swollen, ground-glass nuclei, typical of "decoy cells". Renal biopsy showed degeneration of tubules with epithelial enlargement, vacuolar degeneration, nuclear inclusion bodies, and detachment from the tubular basement membrane. Tubular nuclei showed positive staining positive for simian virus 40 large-T antigen. Polymerase chain reaction tests for BK polyomavirus DNA of both urine and plasma were positive. These findings confirmed a diagnosis of BKPyVAN. Intravenous immunoglobulin therapy did not improve renal function, necessitating maintenance hemodialysis therapy. CONCLUSIONS: BKPyVAN should be considered when acute kidney injury occurs with opportunistic infection. HTLV-1 carriers can develop opportunistic infections even before the onset of ATL.

YAP1/TAZ activity maintains vascular integrity and organismal survival.

Radiation therapy is one of the major treatment modalities for patients with cancers. However, ionizing radiation (IR) damages not only cancer cells but also the surrounding vascular endothelial cells (ECs). Hippo pathway effector genes Yap1 and Taz are the two transcriptional coactivators that have crucial roles in tissue homeostasis and vascular integrity in various organs. However, their function in adult ECs at the steady state and after IR is poorly understood. Here, we report sex- and context-dependent roles of endothelial YAP1/TAZ in maintaining vascular integrity and organismal survival. EC-specific Yap1/Taz deletion compromised systemic vascular integrity, resulting in lethal circulation failure preferentially in male mice. Furthermore, EC-specific Yap1/Taz deletion induced acute lethality upon sublethal IR that was closely associated with exacerbated systemic vascular dysfunction and circulation failure. Consistent with these findings, RNA-seq analysis revealed downregulation of tight junction genes in Yap1/Taz-deleted ECs. Collectively, our findings highlight the importance of endothelial YAP1/TAZ for maintaining adult vascular function, which may provide clinical implications for preventing organ injury after radiation therapy.

Calreticulin haploinsufficiency augments stem cell activity and is required for onset of myeloproliferative neoplasms in mice.

Mutations in JAK2, myeloproliferative leukemia virus (MPL), or calreticulin (CALR) occur in hematopoietic stem cells (HSCs) and are detected in more than 80% of patients with myeloproliferative neoplasms (MPNs). They are thought to play a driver role in MPN pathogenesis via autosomal activation of the JAK-STAT signaling cascade. Mutant CALR binds to MPL, activates downstream MPL signaling cascades, and induces essential thrombocythemia in mice. However, embryonic lethality of Calr-deficient mice precludes determination of a role for CALR in hematopoiesis. To clarify the role of CALR in normal hematopoiesis and MPN pathogenesis, we generated hematopoietic cell-specific Calr-deficient mice. CALR deficiency had little effect on the leukocyte count, hemoglobin levels, or platelet count in peripheral blood. However, Calr-deficient mice showed some hematopoietic properties of MPN, including decreased erythropoiesis and increased myeloid progenitor cells in the bone marrow and extramedullary hematopoiesis in the spleen. Transplantation experiments revealed that Calr haploinsufficiency promoted the self-renewal capacity of HSCs. We generated CALRdel52 mutant transgenic mice with Calr haploinsufficiency as a model that mimics human MPN patients and found that Calr haploinsufficiency restored the self-renewal capacity of HSCs damaged by CALR mutations. Only recipient mice transplanted with Lineage-Sca1+c-kit+ cells harboring both CALR mutation and Calr haploinsufficiency developed MPN in competitive conditions, showing that CALR haploinsufficiency was necessary for the onset of CALR-mutated MPNs.

Longitudinal assessment of pain management with the pain management index in cancer outpatients receiving chemotherapy.

PURPOSE: The adequacy of pain management for individuals with cancer who receive outpatient chemotherapy is unclear. The primary objective of this study was to assess pain prevalence and intensity in such patients. The secondary objectives included assessment of pain management with the pain management index (PMI) and exploration of predictors of inadequate pain management. METHODS: Cancer patients who received outpatient chemotherapy were enrolled. Patients were required to complete questionnaires covering demographic data and including the Brief Pain Inventory and the Distress Thermometer and Impact Thermometer. The PMI score was determined twice with an interval of at least 3 weeks. RESULTS: Of the 740 patients enrolled in the study, 524 individuals (70.8%) completed all questionnaires. Totals of 282 patients (53.8%) and 264 patients (50.4%) reported pain at baseline and follow-up, respectively, with ∼14% of patients having moderate or severe pain at each assessment. Totals of 365 patients (69.7%) at baseline and 320 patients (61.1%) at follow-up reported pain or were prescribed analgesics, with the rate of inadequate pain management for these patients being 39.7 and 51.6%, respectively. Multivariable analysis for 418 patients (79.8%) who had pain or required analgesics at baseline or follow-up (or both) revealed that the most significant predictor of inadequate pain management was depressive state. CONCLUSIONS: Pain in cancer patients receiving outpatient chemotherapy is prevalent and at risk for undertreatment. Pain management should be assessed on a regular basis and is likely to be improved by screening for depression.

Prevalence of Airflow Limitation Defined by Pre- and Post-Bronchodilator Spirometry in a Community-Based Health Checkup: The Hisayama Study.

Spirometry in health checkup may contribute to early diagnosis of chronic obstructive pulmonary disease (COPD) and asthma. Although post-bronchodilator airflow limitation is essential for definite diagnosis of COPD and post-bronchodilator normalization of airflow is suggestive of asthma, this test has not been prevailed in health checkup. The objective of this study was to estimate the prevalence of airflow limitation defined by pre- and post-bronchodilator spirometry in health checkup. Post-bronchodilator spirometry was conducted for participants with airflow limitation in a town-wide health checkup for residents aged 40 years and older in Hisayama, a town in the western part of Japan. The prevalence of pre- and post-bronchodilator airway limitation defined by FEV1/FVC < 70% were estimated. A total of 2,232 participants underwent pre-bronchodilator spirometry. In males, the age of current smokers was significantly younger than those of never smokers and former smokers. In females, the ages of current- and former smokers were significantly younger than never smokers. The values of %FEV1 and %FVC in current smokers were significantly lower than those in former smokers and never smokers. Two hundred sixty nine subjects, 85% of total subjects with a pre-bronchodilator FEV1/FVC < 70%, completed post-bronchodilator spirometry. The prevalence of pre-bronchodilator airflow limitation was 14.6% in males and 13.7% in females, and the prevalence of post-bronchodilator airway limitation was 8.7% and 8.7%, respectively. Post-bronchodilator spirometry in health checkup would reduce the number of subjects with probable COPD to two-third. Recommendation for those examinees to take further evaluations may pave the way for early intervention.

Small interfering RNA against CD86 during allergen challenge blocks experimental allergic asthma.

BACKGROUND: CD86-CD28 interaction has been suggested as the principal costimulatory pathway for the activation and differentiation of naïve T cells in allergic inflammation. However, it remains uncertain whether this pathway also has an essential role in the effector phase. We sought to determine the contribution of CD86 on dendritic cells in the reactivation of allergen-specific Th2 cells. METHODS: We investigated the effects of the downregulation of CD86 by short interfering RNAs (siRNAs) on Th2 cytokine production in the effector phase in vitro and on asthma phenotypes in ovalbumin (OVA)-sensitized and -challenged mice. RESULTS: Treatment of bone marrow-derived dendritic cells (BMDCs) with CD86 siRNA attenuated LPS-induced upregulation of CD86. CD86 siRNA treatment impaired BMDCs' ability to activate OVA-specific Th2 cells. Intratracheal administration of CD86 siRNA during OVA challenge downregulated CD86 expression in the airway mucosa. CD86 siRNA treatment ameliorated OVA-induced airway eosinophilia, airway hyperresponsiveness, and the elevations of OVA-specific IgE in the sera and IL-5, IL-13, and CCL17 in the bronchoalveolar lavage fluid, but not the goblet cell hyperplasia. CONCLUSION: These results suggest that local administration of CD86 siRNA during the effector phase ameliorates lines of asthma phenotypes. Targeting airway dendritic cells with siRNA suppresses airway inflammation and hyperresponsiveness in an experimental model of allergic asthma.

TIF1ß activates leukemic transcriptional program in HSCs and promotes BCR::ABL1-induced myeloid leukemia.

TIF1ß/KAP1/TRIM28, a chromatin modulator, both represses and activates the transcription of genes in normal and malignant cells. Analyses of datasets on leukemia patients revealed that the expression level of TIF1ß was increased in patients with chronic myeloid leukemia at the blast crisis and acute myeloid leukemia. We generated a BCR::ABL1 conditional knock-in (KI) mouse model, which developed aggressive myeloid leukemia, and demonstrated that the deletion of the Tif1ß gene inhibited the progression of myeloid leukemia and showed longer survival than that in BCR::ABL1 KI mice, suggesting that Tif1ß drove the progression of BCR::ABL1-induced leukemia. In addition, the deletion of Tif1ß sensitized BCR::ABL1 KI leukemic cells to dasatinib. The deletion of Tif1ß decreased the expression levels of TIF1ß-target genes and chromatin accessibility peaks enriched with the Fosl1-binding motif in BCR::ABL1 KI stem cells. TIF1ß directly bound to the promoters of proliferation genes, such as FOSL1, in human BCR::ABL1 cells, in which TIF1ß and FOSL1 bound to adjacent regions of chromatin. Since the expression of Fosl1 was critical for the enhanced growth of BCR::ABL1 KI cells, Tif1ß and Fosl1 interacted to activate the leukemic transcriptional program in and cellular function of BCR::ABL1 KI stem cells and drove the progression of myeloid leukemia.

Effects of tiotropium on lung function in severe asthmatics with or without emphysematous changes.

The effects of tiotropium, an inhaled long-acting anti-cholinergic agent, on lung function were investigated in obstructed severe asthmatics with and without emphysematous changes despite maximal recommended treatments with high-dose of inhaled glucocorticoids and inhaled long-acting ß(2)-agonists. We conducted a double-blind, placebo-controlled study of an inhaled single-dose of tiotropium in 18 asthmatics with emphysema and 18 without emphysema in a crossover manner. The primary efficacy outcome was the relative change in forced expiratory volume in 1 s (FEV(1)) from baseline to 60 min, and the secondary outcome was a relative change in FEV(1) from baseline to 12 h. Subsequently, the patients were treated with tiotropium inhaled once daily for 12 weeks in an open label manner, and lung function and symptoms were evaluated. At baseline, patients with or without emphysema had a mean FEV(1) of 55.9% before tiotropium and 56.8% before placebo, or 77.4% before tiotropium and 77.6% before placebo of the predicted value and were taking a mean dose of inhaled glucocorticoids of 1444 or 1422 µg/day. Among patients with emphysema, the increase from baseline FEV(1) was 12.6 percentage points higher at 60 min after tiotropium than after placebo. Among patients without emphysema, the increase from baseline FEV(1) was 5.4 percentage points higher at 60 min after tiotropium than after placebo. Tiotropium resulted in improved lung function and symptoms in asthmatics with and without emphysema. These findings suggest that tiotropium will provide a new strategy for the treatment of bronchial asthma and of overlapping asthma and COPD.

Exposure to microbial products followed by loss of Tet2 promotes myelodysplastic syndrome via remodeling HSCs.

Aberrant innate immune signaling in myelodysplastic syndrome (MDS) hematopoietic stem/progenitor cells (HSPCs) has been implicated as a driver of the development of MDS. We herein demonstrated that a prior stimulation with bacterial and viral products followed by loss of the Tet2 gene facilitated the development of MDS via up-regulating the target genes of the Elf1 transcription factor and remodeling the epigenome in hematopoietic stem cells (HSCs) in a manner that was dependent on Polo-like kinases (Plk) downstream of Tlr3/4-Trif signaling but did not increase genomic mutations. The pharmacological inhibition of Plk function or the knockdown of Elf1 expression was sufficient to prevent the epigenetic remodeling in HSCs and diminish the enhanced clonogenicity and the impaired erythropoiesis. Moreover, this Elf1-target signature was significantly enriched in MDS HSPCs in humans. Therefore, prior infection stress and the acquisition of a driver mutation remodeled the transcriptional and epigenetic landscapes and cellular functions in HSCs via the Trif-Plk-Elf1 axis, which promoted the development of MDS.

Differences in the spectrum of respiratory viruses and detection of human rhinovirus C in exacerbations of adult asthma and chronic obstructive pulmonary disease.

BACKGROUND: Viral respiratory infections are a common cause of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) and asthma. We conducted a multicenter prospective study to determine the differences in the spectrum of viruses between adults with asthma exacerbations and AECOPD and assessed the prevalence and impact of human rhinovirus (HRV)-C in adults, which is more pathogenic in children with asthma than other HRV species. METHODS: Nasopharyngeal and serum samples and clinical information were collected from 64 outpatients with adult asthma exacerbations and 44 outpatients with AECOPD between April 2018 and March 2020. Viral pathogens and HRV strains were identified from nasal samples by multiplex PCR and VP4/VP2 nested PCR. RESULTS: Viral pathogens were identified in 31 patients with asthma exacerbations (48.4%) and 17 patients with AECOPD (38.6%). The most commonly detected viruses were HRV/enterovirus followed by human metapneumovirus (hMPV) in patients with asthma exacerbations, and hMPV followed by parainfluenza virus in patients with AECOPD. HRV-C was the HRV species most commonly associated with both asthma exacerbations and AECOPD. Clinical characteristics, baseline lung function, serum inflammatory chemokines, hospitalization, and systemic steroid use did not differ between HRV-C-positive patients and those positive for other HRV species. CONCLUSIONS: Exacerbation-associated spectrum of viruses differed between adults with asthma exacerbations and AECOPD. HRV-C was the HRV species most often observed in adult asthma exacerbations and AECOPD, although it did not worsen patients' clinical outcomes relative to those of patients with other HRVs. Underlying disease-specific factors may be responsible for susceptibility to respiratory viruses. TRIAL REGISTRATION: UMIN-CTR UMIN000031934.

The acidic domain of Hmga2 and the domain's linker region are critical for driving self-renewal of hematopoietic stem cell.

High mobility group AT-hook 2 (Hmga2) is a chromatin modifier protein that plays a critical role in fetal development and leukemia propagation by binding to chromatin and DNA via its AT-hook domains. However, the molecular mechanisms by which Hmga2 activates the expression of target genes to drive the self-renewal of hematopoietic stem cells (HSCs) remain unclear. We generated Rosa26 locus Hmga2 conditional knock-in mice and found that overexpression of Hmga2 promoted self-renewal of normal HSCs, but maintained their fitness in bone marrow, and consequently was not sufficient to initiate malignancy. This result is consistent with previous findings showing that Hmga2 is a proto-oncogene. We also assessed the cellular functions of Hmga2 mutants lacking functional domains and demonstrated that the C-terminus acidic domain of Hmga2 and the domain's linker region were critical for activating genes involved in stem cell signatures, such as the Igf2bp2 gene, to drive proliferation of HSCs. In contrast, overexpression of Hmga1, a member of the Hmga family with a different linker region, did not drive proliferation of HSCs. Our results reveal a critical role for the acidic domain of Hmga2 and the domain's linker region in modulating the transcription and self-renewal functions of HSCs.

CARD11 mutation and HBZ expression induce lymphoproliferative disease and adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATL) is caused by human T-cell leukemia virus type 1 (HTLV-1). In addition to HTLV-1 bZIP factor (HBZ), a leukemogenic antisense transcript of HTLV-1, abnormalities of genes involved in TCR-NF-κB signaling, such as CARD11, are detected in about 90% of patients. Utilizing mice expressing CD4+ T cell-specific CARD11(E626K) and/or CD4+ T cell-specific HBZ, namely CARD11(E626K)CD4-Cre mice, HBZ transgenic (Tg) mice, and CARD11(E626K)CD4-Cre;HBZ Tg double transgenic mice, we clarify these genes' pathogenetic effects. CARD11(E626K)CD4-Cre and HBZ Tg mice exhibit lymphocytic invasion to many organs, including the lungs, and double transgenic mice develop lymphoproliferative disease and increase CD4+ T cells in vivo. CARD11(E626K) and HBZ cooperatively activate the non-canonical NF-κB pathway, IRF4 targets, BATF3/IRF4/HBZ transcriptional network, MYC targets, and E2F targets. Most KEGG and HALLMARK gene sets enriched in acute-type ATL are also enriched in double transgenic mice, indicating that these genes cooperatively contribute to ATL development.

T cell treatment with small interfering RNA for suppressor of cytokine signaling 3 modulates allergic airway responses in a murine model of asthma.

CD4(+) T cells, particularly T helper (Th) 2 cells, play a pivotal role in the pathophysiology of allergic asthma. Suppressor of cytokine signaling (SOCS) proteins control the balance of CD4(+) T cell differentiation. Mice that lack SOCS3 in T cells by crossing SOCS3-floxed mice with Lck-Cre-transgenic mice have reduced allergen-induced eosinophilia in the airways. Here, we studied the effects of SOCS3 silencing with small interfering (si) RNA in primary CD4(+) T cells on Th2 cell differentiation and on asthmatic responses in mice. Th2 cells were generated from ovalbumin (OVA)-specific T cell receptor-transgenic mice in vitro and transferred into recipient mice. Transfection of SOCS3-specific siRNA attenuated Th2 response in vitro. Adoptive transfer of SOCS3-siRNA T cells exhibited markedly suppressed airway hyperresponsiveness and eosinophilia after OVA challenge, with a concomitant decrease in OVA-specific CD4(+) T cell accumulation in the airways. To investigate the mechanism of this impaired CD4(+) T cell accumulation, we inactivated SOCS3 of T cells by crossing SOCS3-floxed (SOCS3(flox/flox)) mice with CD4-Cre transgenic mice. CD4-Cre × SOCS3(flox/flox) mice exhibited fewer IL-4-producing cells and more reduced eosinophil infiltration in bronchoalveolar lavage fluids than control mice in a model of OVA-induced asthma. Expression of CCR3 and CCR4 in CD4(+) T cells was decreased in CD4-Cre × SOCS3(flox/flox) mice. CCR4 expression was also decreased in CD4(+) T cells after transfer of SOCS3 siRNA-treated T cells. These findings suggest that the therapeutic modulation of SOCS3 expression in CD4(+) T cells might be effective in preventing the development of allergic asthma.

Spred-1 negatively regulates allergen-induced airway eosinophilia and hyperresponsiveness.

T helper 2 cytokines, including interleukin (IL)-4, IL-5, and IL-13, play a critical role in allergic asthma. These cytokines transmit signals through the Janus kinase/signal transducer and activator of transcription (STAT) and the Ras-extracellular signal-regulated kinase (ERK) signaling pathways. Although the suppressor of cytokine signaling (SOCS) family proteins have been shown to regulate the STAT pathway, the mechanism regulating the ERK pathway has not been clarified. The Sprouty-related Ena/VASP homology 1-domain-containing protein (Spred)-1 has recently been identified as a negative regulator of growth factor-mediated, Ras-dependent ERK activation. Here, using Spred-1-deficient mice, we demonstrated that Spred-1 negatively regulates allergen-induced airway eosinophilia and hyperresponsiveness, without affecting helper T cell differentiation. Biochemical assays indicate that Spred-1 suppresses IL-5-dependent cell proliferation and ERK activation. These data indicate that Spred-1 negatively controls eosinophil numbers and functions by modulating IL-5 signaling in allergic asthma.

A zinc chelator TPEN attenuates airway hyperresponsiveness and airway inflammation in mice in vivo.

BACKGROUND: Zinc is an essential element required for the cell metabolism, including gene transcription, signal transduction, immunity, and apoptosis. The pathophysiological role of zinc in asthma, however, is not entirely clear. Mast cells have been implicated in atopic asthma, and zinc deprivation has been reported to reduce mast cell activation. Here, we investigate the effects of a zinc chelator, N,N,N',N'-tetrakis (2-pyridyl-methyl) ethylenediamine (TPEN), on asthmatic responses in mouse models of ovalbumin (OVA)-induced airway hyperresponsiveness and allergic airway inflammation. METHODS: Mice were sensitized with OVA with or without the adjuvant aluminum hydroxide (alum) and subjected to OVA exposure with or without treatment of TPEN. Cell profiles and cytokine levels in bronchoalveolar lavage (BAL) fluids, airway responsiveness to inhaled acetylcholine, and goblet cell hyperplasia after allergen exposure were assessed. RESULTS: In mice sensitized to OVA without alum, TPEN significantly suppressed airway hyperresponsiveness and eosinophilia in BAL fluids. TPEN also attenuated the upregulation of TNFα, IL-13 and IL-4 in BAL fluids and goblet cell hyperplasia after OVA exposure. By contrast, in mice sensitized to OVA with alum, TPEN suppressed eosinophilia in BAL fluids but not airway hyperresponsiveness and goblet cell hyperplasia. CONCLUSIONS: In pulmonary allergic inflammation induced in mice immunized with antigen without alum, zinc chelator inhibits airway inflammation and hyperresponsiveness. These findings suggest that zinc may be a therapeutic target of allergic asthma.

Two faces of RUNX3 in myeloid transformation.

RUNX3, a transcription factor, has been implicated as a tumor suppressor in various cancers, including hematological malignancies; however, recent studies revealed an oncogenic function of RUNX3 in the pathogenesis of myeloid malignancies, such as myelodysplastic syndrome and acute myeloid leukemia. In contrast to the high frequency of mutations in the RUNX1 gene, deletion of and loss-of-function mutations in RUNX3 are rarely detected in patients with hematopoietic malignancies. Although RUNX3 is expressed in normal hematopoietic stem and progenitor cells, its expression decreases with aging in humans. The loss of Runx3 did not result in the development of lethal hematological diseases in mice despite the expansion of myeloid cells. Therefore, RUNX3 does not appear to initiate the transformation of normal hematopoietic stem cells. However, the overexpression of RUNX3 inhibits the expression and transcriptional function of the RUNX1 gene, but activates the expression of key oncogenic pathways, such as MYC, resulting in the transformation of premalignant stem cells harboring a driver genetic mutation. We herein discuss the mechanisms by which RUNX3 is activated and how RUNX3 exerts oncogenic effects on the cellular function of and transcriptional program in premalignant stem cells to drive myeloid transformation.