iNKT cells with high PLZF expression are recruited into the lung via CCL21-CCR7 signaling to facilitate the development of asthma tolerance in mice.

Establishment of immune tolerance is crucial to protect humans against asthma. Promyelocytic leukemia zinc finger (PLZF) is an emerging suppressor of inflammatory responses. CCL21-CCR7 signaling mediates tolerance development. However, whether PLZF and CCL21-CCR7 are required for the development of asthma tolerance is unknown. Here, we found that Zbtb16 (coding PLZF) and Ccl21 were upregulated in OVA-induced asthma tolerance (OT) lungs by RNA-seq. PLZF physically interacted with GATA3 and its expression was higher in GATA3+ Th2 cells and ILC2s in OT lungs. Zbtb16-knockdown in lymphocytes promoted the differentiation of CD3e+ CD4+ T cells, particularly those producing IL-4 and IL-5. Moreover, iNKT cells with high expression of PLZF were recruited into the lungs via draining lymph nodes during tolerance. Blockade of CCL21-CCR7 signaling in OT mice decreased the PLZF+  cell population, abolished CCR7-induced PLZF+ iNKT recruitment to the lungs, enhanced Th2responses and exacerbated lung pathology. In OT mice, respiratory syncytial virus (RSV) infection impeded PLZF+  cell and CCR7+ PLZF+ iNKT cellrecruitment to the lungs and increased airway resistance. Collectively, these results indicate that PLZF could interact with GATA3 and restrain differentiation of IL-4- and IL-5-producing T cells, iNKT cells with high PLZF expression are recruited to the lungs via CCL21-CCR7 signaling to facilitate the development of asthma tolerance.

Thrombin cleaves IL-33 and modulates IL-33-activated allergic lung inflammation.

BACKGROUND: Organisms have orchestrated coagulation and immune systems. Although a link between inflammation and haemostasis has been reported in asthma, the interaction mechanism has not been completely elucidated. Here, we investigated the direct link between the mammalian immune and coagulation systems. METHODS: Mice were administered protease or antigens intranasally to induce airway inflammation with or without thrombin inhibitors treatment. The effects of thrombin and its inhibitors on interleukin (IL)-33 were investigated both in vivo and in vitro. Peripheral blood mononuclear cells (PBMCs) and plasma from asthma patients are collected to verify the correlation between thrombin and group 2 innate lymphocytes (ILC2s). RESULTS: Low-molecular-weight heparin (LMWH, an indirect inhibitor of thrombin) restrained both papain- and fungus-induced type 2 immune responses in mice by inhibiting IL-33 cleavage. Upon examining the potential thrombin protease consensus sites, we found that IL-33 was directly cleaved by thrombin at specific amino acids (R48 and R106) to generate a mature form of IL-33 with potent biological activity. In addition, we found that bivalirudin TFA (a direct inhibitor of thrombin) inhibited a variety of type 2 inflammatory responses, such as those in house dust mite (HDM)- and ovalbumin (OVA)-mediated pulmonary inflammation models. We found that plasma thrombin-antithrombin complex (TATc) levels in asthma patients were positively associated with the number and function of IL-33-responder group 2 innate lymphocytes (ILC2s) among peripheral blood mononuclear cells (PBMCs) from asthma patients. CONCLUSION: The data suggested that thrombin inhibitors administration could be effective in treating lung inflammation by regulating ILC2s via IL-33 maturation, indicating that targeting thrombin is a potential way to treat allergic diseases.

Long noncoding RNA GAS5 attenuates cigarette smoke-induced airway remodeling by regulating miR-217-5p/PTEN axis.

Airway remodeling is a remarkable pathological characteristic of chronic obstructive pulmonary disease (COPD), and long noncoding RNAs have been demonstrated to participate in COPD development and pathogenesis. Here, we investigate the role of long noncoding RNA GAS5 in cigarette smoke (CS)-induced airway remodeling. GAS5 expression is significantly lower in lung tissues of CS-exposed mice than in tissues of control mice without exposure to CS. Forced GAS5 overexpression suppresses CS-induced airway inflammation and remodeling. GAS5 overexpression also inhibits CS extract-induced inflammatory-cytokine expression and fibroblast activation in vitro. Regarding the mechanism, GAS5 acts as a sponge of miR-217-5p, thereby increasing PTEN expression. MiR-217-5p overexpression and PTEN knockdown separately reverse the inhibitory effects of GAS5 overexpression on the inflammatory-cytokine expression and fibroblast activation. Collectively, these results suggest that GAS5 can suppress airway inflammation and fibroblast activation by regulating miR-217-5p/PTEN axis, which may help develop novel therapeutic strategies against COPD.

Vagal-α7nAChR signaling attenuates allergic asthma responses and facilitates asthma tolerance by regulating inflammatory group 2 innate lymphoid cells.

Disorders of immune tolerance may lead to allergic asthma. Group 2 innate lymphoid cells (ILC2s) and inflammatory ILC2s (iILC2s) are key players in asthma. The vagus nerve innervating the airways releases acetylcholine or neuropeptides (i.e. calcitonin gene-related peptide) via pulmonary C-fibers (PCFs), which could regulate ILC2 activity upon binding the α7 nicotinic acetylcholine receptor (α7nAChR, coded by Chrna7) or neuropeptide receptors. Whether and how α7nAChR and PCFs regulate asthma and the formation of asthma tolerance via ILC2s or iILC2s are poorly understood. We used vagotomized, PCF degeneration and Chrna7 knockout mice to investigate ovalbumin (OVA)-induced asthma and oral OVA feeding-induced asthma tolerance. Our results revealed that vagotomy could generally suppress lung ILC2s and iILC2s, which mitigated allergic asthma responses but disrupted asthmatic tolerance. Removal of neuropeptides by PCF degeneration also reduced lung ILC2s and iILC2s, attenuating asthma responses, but did not affect asthma tolerance. In comparison, deletion of Chrna7 increased resident ILC2s and trafficking iILC2s in the lung, worsened allergic inflammation and disrupted oral tolerance. Mechanistically, deletion of Chrna7 in asthma-tolerant conditions upregulated T helper 2 cytokine- (Il4, Il13 and Il25) and sphingosine-1-phosphate (S1P)-related genes (S1pr1 and Sphk1). Blockade of S1P reduced iILC2 recruitment into asthmatic lungs. Our work is the first to demonstrate that vagal-α7nAChR signaling engaging with iILC2s and S1P not only alleviates asthma but also facilitates asthma tolerance. These findings may provide a novel therapeutic target for attenuating asthma by enhancing asthmatic tolerance.

Study design for a multicenter, randomized controlled trial evaluating the diagnostic value of ultrathin bronchoscope compared to thin bronchoscope without fluoroscopy for peripheral pulmonary lesions.

Background: Ultrathin bronchoscope (UTB) with a 3.0-mm outer diameter and a 1.7-mm working channel currently appeared as a potential tool for better biopsy and diagnosis of peripheral pulmonary lesions (PPLs) by accessing more distal bronchus. However, published research is primarily limited to diagnosis value of UTB for PPLs with fluoroscopy, the value of UTB compared with thin bronchoscope (TB) without fluoroscopy guidance has not been determined yet. Methods: We design a prospective, randomized, controlled, non-inferior, multicenter study aiming to evaluate the diagnostic value and safety of UTB for PPLs with the guidance of virtual bronchoscopic navigation (VBN) combined with endobronchial ultrasound (EBUS) without fluoroscopy by comparing to TB. The study aims to enroll 578 patients presenting for evaluation of PPLs at five clinical sites in China. Subjects will be randomized to UTB-VBN-EBUS group, TB-VBN-EBUS-guide sheath (GS) group, and TB-VBN-EBUS-non-GS group. Primary endpoint is the diagnostic yield of PPLs. The total examination time, duration of finding lesions, the proportion of lesions visible by radial EBUS, factors affecting the diagnostic yield, difference in the bronchus level reached with the bronchoscope, difference in diagnostic yield, and complication rate will be determined as secondary endpoints. The primary endpoint will be followed-up at least 6-month post-procedure and 1-month post-procedure for safety endpoint. Discussion: Study enrollment began in March 2021. Our preliminary experience reveals that UTB is a powerful tool in the diagnosis of PPLs even without fluoroscopy. The results of the current study will compensate the limitations of the previous research, further provide evidence of UTB in diagnosing PPLs without fluoroscopy. Trial Registration: ClinicalTrials.gov NCT04571476. Registered on 30 September 2020.

Suppression of circXPO1 attenuates cigarette smoke-induced inflammation and cellular senescence of alveolar epithelial cells in chronic obstructive pulmonary disease.

Smoking is an essential facet of the pathogenesis of chronic obstructive pulmonary disease (COPD), which is typically characterized by inflammation and cellular senescence of alveolar epithelial cells. In this study, we investigated the function and fundamental mechanism of a novel circular RNA XPO1 (circXPO1) in cigarette smoke (CS)-induced inflammation and cellular senescence of alveolar epithelial cells. We found that circXPO1 was overexpressed in the lungs of CS-exposed mice and the CS extract (CSE)-treated alveolar epithelial cell line MLE12. Suppression of circXPO1 inhibited CSE-induced inflammatory cytokine production and cellular senescence. In vivo assays also demonstrated that circXPO1 knockdown attenuates CS-induced inflammation and senescence in the mouse lungs. Mechanistically, circXPO1 can directly bind to miR-23b-3p, preventing miR-23b-3p from binding to its target TGF-ß-activated kinase 1/MAP3K7 binding protein 3 (TAB3)mRNA. In addition, under CSE conditions, miR-23b-3p overexpression recapitulated the prophylactic effects of circXPO1 knockdown. Inhibition of miR-23b-3p attenuated the function of circXPO1 knockdown in CSE-treated MLE12 cells. These results reveal that circXPO1 plays a role in the pathogenesis of COPD by modulating TAB3 through sponging miR-23b-3p.

Progress and Current Status of Influenza Researches in China.

Influenza pandemics with different extent occur every year in the world. It can cause high morbidity and mortality, arouse fear panic in public, and attract extensive attention worldwide. This paper reviews the research progress in epidemiological characteristics, detection methods, pathogenesis, treatment and prophylactic measures of influenza in China. It will be helpful for us to understand the current situation of influenza.

Inhibition of microRNA-34a prevents IL-1ß-induced extracellular matrix degradation in nucleus pulposus by increasing GDF5 expression.

Accumulating evidence indicates that miRNAs, a class of small non-coding RNAs, are implicated in the pathogenesis of various diseases such as cancer and intervertebral disc degeneration. The aim of this study was to investigate the expression and the biological function of microRNA-34a in intervertebral disc degeneration. In this study, microRNA-34a expression was assessed in nucleus pulposus specimens and in IL-1ß-stimulated nucleus pulposus cells by real-time polymerase chain reaction. microRNA-34a functions were investigated by using gain and loss of function experiments in nucleus pulposus cells and a dual luciferase reporter assay in 293T cells. microRNA-34a was dramatically up-regulated in degenerative nucleus pulposus tissues and in IL-1ß-stimulated nucleus pulposus cells when compared with controls. Furthermore, growth differentiation factor 5 was identified as a target of microRNA-34a. Aberrant expression of microRNA-34a inhibited growth differentiation factor 5 expression by direct binding to its 3'-untranslated region. This inhibition was abolished by mutation of the microRNA-34a binding sites. In addition, microRNA-34a silencing reversed IL-1ß-induced decrease in type II collagen and aggrecan expression in nucleus pulposus cells. This effect was substantially suppressed by growth differentiation factor 5 silencing. Our results suggested that microRNA-34a inhibition prevents IL-1ß-induced extracellular matrix degradation in human nucleus pulposus by increasing growth differentiation factor 5 expression. microRNA-34a inhibition may be a novel molecular target for intervertebral disc degeneration treatment through the prevention of nucleus pulposus extracellular matrix degradation.

MicroRNA-7 regulates IL-1ß-induced extracellular matrix degeneration by targeting GDF5 in human nucleus pulposus cells.

The precise role of interleukin-1 beta (IL-1ß)-induced extracellular matrix degeneration in the pathogenesis of intervertebral disc degeneration (IDD) is currently unknown. Recent evidence has revealed that microRNAs (miRNAs) are associated with IDD, but their function in the extracellular matrix degradation of nucleus pulposus (NP) tissues is also poorly understood. The aim of this study was to evaluate the expression and functional role of miR-7 in IL-1ß-induced disc degeneration. The expression level of miR-7 was investigated in degenerative NP tissues and in IL-1ß-induced NP cells using quantitative reverse transcription-polymerase chain reaction amplification analysis. A dual-luciferase reporter assay was then utilized to determine whether growth differentiation factor 5 (GDF5) is a target of miR-7. Finally, mRNA and protein levels of known matrix components and of matrix degradation enzymes were determined to elucidate the function of miR-7 in IL-1ß-induced disc degeneration. In this study, we found that miR-7 is highly expressed in human degenerative NP tissues and in IL-1ß stimulated NP cells compared to normal controls. We also determined that GDF5 was a target of miR-7. Functional analysis showed that the overexpression of miR-7 significantly enhanced the IL-1ß-induced extracellular matrix degeneration, whereas inhibition of miR-7 function by antagomiR-7 prevented NP cell detrimental catabolic changes in response to IL-1ß. Additionally, the prevention of IL-1ß-induced NP extracellular matrix degeneration by miR-7 silencing was attenuated by GDF5 siRNA. These findings suggest that miR-7 contributes to an impaired ECM in intervertebral discs through targeting GDF5 and miR-7 might therefore represent a novel therapeutic target for the prevention of IDD.