Stabilization of the hexasome intermediate during histone exchange by yeast SWR1 complex.

The yeast SWR1 complex catalyzes the exchange of histone H2A/H2B dimers in nucleosomes with Htz1/H2B dimers. We use cryoelectron microscopy to determine the structure of an enzyme-bound hexasome intermediate in the reaction pathway of histone exchange, in which an H2A/H2B dimer has been extracted from a nucleosome prior to the insertion of a dimer comprising Htz1/H2B. The structure reveals a key role for the Swc5 subunit in stabilizing the unwrapping of DNA from the histone core of the hexasome. By engineering a crosslink between an Htz1/H2B dimer and its chaperone protein Chz1, we show that this blocks histone exchange by SWR1 but allows the incoming chaperone-dimer complex to insert into the hexasome. We use this reagent to trap an SWR1/hexasome complex with an incoming Htz1/H2B dimer that shows how the reaction progresses to the next step. Taken together the structures reveal insights into the mechanism of histone exchange by SWR1 complex.

Conditional knockout of ITGB4 in bronchial epithelial cells directs bronchopulmonary dysplasia.

Neonatal respiratory system disease is closely associated with embryonic lung development. Our group found that integrin ß4 (ITGB4) is downregulated in the airway epithelium of asthma patients. Asthma is the most common chronic respiratory illness in childhood. Therefore, we suspect whether the deletion of ITGB4 would affect fetal lung development. In this study, we characterized the role of ITGB4 deficiency in bronchopulmonary dysplasia (BPD). ITGB4 was conditionally knocked out in CCSP-rtTA, Tet-O-Cre and ITGB4f/f triple transgenic mice. Lung tissues at different developmental stages were collected for experimental detection and transcriptome sequencing. The effects of ITGB4 deficiency on lung branching morphogenesis were observed by fetal mouse lung explant culture. Deleting ITGB4 from the airway epithelial cells results in enlargement of alveolar airspaces, inhibition of branching, the abnormal structure of epithelium cells and the impairment of cilia growth during lung development. Scanning electron microscopy showed that the airway epithelial cilia of the ß4ccsp.cre group appear to be sparse, shortened and lodging. Lung-development-relevant factors such as SftpC and SOX2 significantly decreased both mRNA and protein levels. KEGG pathway analysis indicated that multiple ontogenesis-regulating-relevant pathways converge to FAK. Accordingly, ITGB4 deletion decreased phospho-FAK, phospho-GSK3ß and SOX2 levels, and the correspondingly contrary consequence was detected after treatment with GSK3ß agonist (wortmannin). Airway branching defect of ß4ccsp.cre mice lung explants was also partly recovered after wortmannin treatment. Airway epithelial-specific deletion of ITGB4 contributes to lung developmental defect, which could be achieved through the FAK/GSK3ß/SOX2 signal pathway.

CTNNAL1 deficiency suppresses CFTR expression in HDM-induced asthma mouse model through ROCK1-CAL signaling pathway.

The downregulation of adhesion molecule catenin alpha-like 1 (CTNNAL1) in airway epithelial cells of asthma patients and house dust mite (HDM)-induced asthma animal models was illustrated in our previous study. It is assumed to contribute to airway inflammation and mucus hypersecretion. In this work, we further explore the underlying mechanism of CTNNAL1 in asthma. CTNNAL1-silenced female mice exhibit a decreased level of cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-activated and ATP-gated Cl - channel that correlates with mucus hypersecretion. Our previous study demonstrated that ROCK1 expression decreases but ROCK2 expression increases in the lungs of a CTNNAL1-silenced mouse model. Inhibition of ROCK1 leads to a reduction in CFTR expression in CTNNAL1-overexpressing and CTNNAL1-silenced human bronchial epithelial (HBE) cells. It has been reported that ROCK1 is a downstream target of RhoA and that activation of RhoA increases CFTR expression after CTNNAL1 deficiency in vitro and in vivo. The above results indicate that CTNNAL1 regulates CFTR expression through the ROCK1 pathway. In addition, the expression of CFTR-associated ligand (CAL) is increased after CTNNAL1 silencing, and immunoprecipitation results confirm the interaction between ROCK1 and CAL. Inhibition of CAL does not influence ROCK1 expression but increases CFTR expression in CTNNAL1-silenced HBE cells. These data suggest that CTNNAL1 deficiency decreases CFTR expression in the HDM-induced asthma mouse model through the ROCK1-CAL signaling pathway.

CTNNAL1 participates in the regulation of mucus overproduction in HDM-induced asthma mouse model through the YAP-ROCK2 pathway.

Our previous study indicated that adhesion molecule catenin alpha-like 1(CTNNAL1) is downregulated in airway epithelial cells of asthma patients and asthma animal model but little is known about how the CTNNAL1 affects asthma pathogenesis. To reveal the direct relationship between asthma and CTNNAL1, CTNNAL1-deficient mouse model in bronchopulmonary tissue was constructed by introducing CTNNAL1-siRNA sequence using adeno-associated virus (AAV) as vector. The mouse model of asthma was established by stimulation of house dust mite (HDM). After HDM-challenged, there was marked airway inflammation, especially mucus hypersecretion in the CTNNAL1-deficient mice. In addition, the CTNNAL1-deficient mice exhibited an increase of lung IL-4 and IL-13 levels, as well as a significant increase of goblet cell hyperplasia and MUC5AC after HDM exposure. The expression of Yes-associated protein (YAP), protein that interacted with α-catenin, was downregulated after CTNNAL1 silencing and was upregulated due to its overexpression. In addition, the interaction between CTNNAL1 and YAP was confirmed by CO-IP. Besides, inhibition of YAP could decrease the secretion of MUC5AC, IL-4 and IL-13 in CTNNAL1-deficient 16HBE14o-cells. Above results indicated us that CTNNAL1 regulated mucus hypersecretion through YAP pathway. In addition, the expression of ROCK2 increased when CTNNAL1 was silenced and decreased after YAP silencing, and inhibition of YAP decreased the expression of ROCK2 in CTNNAL1-deficient HBE cells. Inhibition of ROCK2 decreased MUC5AC expression and IL-13 secretion. In all, our study demonstrates that CTNNAL1 plays an important role in HDM-induced asthma, mediating mucus secretion through the YAP-ROCK2 pathway.

CTNNAL1 enhances glucocorticoid sensitivity in HDM-induced asthma mouse model through deactivating hsp90 signaling pathway.

AIMS: Adhesion molecules play vital roles in the induction of airway hyperresponsiveness (AHR) or airway inflammation. The down-regulation of catenin alpha-like 1 (CTNNAL1) in the bronchial epithelial cells of asthma patients and mice models has been noted in our previous study. In this work, we further explore the underlying mechanism of CTNNAL1 in asthma. MAIN METHODS: We constructed a house dust mite (HDM)-induced asthma animal model on control mice and applied CTNNAL1-siRNA transfection to create CTNNAL1-deficient mice. KEY FINDINGS: We documented much more severe airway inflammation and increased leukocyte infiltration in the lungs of the CTNNAL1-deficient mice comparing to control mice, along with elevated expression of inflammatory cytokines. Dexamethasone (DEX) treatment led to less reduced inflammation in CTNNAL1-deficient mice compared with control mice. Immunoprecipitation confirmed the interaction between heat shock protein90 (hsp90) and CTNNAL1. The expression of hsp90 was upregulated after CTNNAL1 silencing. Meanwhile, the use of hsp90 inhibitor geldanamycin significantly decreased the expression of NR3C1, ICAM-1 and the ratio of p-p65/p65 in CTNNAL1-silenced 16HBE14o- cells. Both geldanamycin and DEX could function to suppress the expression of ICAM-1 and the phosphorylation level of p65. Nevertheless, the anti-inflammatory effect of DEX proved less potent than geldanamycin in the CTNNAL1-silenced group. The combined therapy of geldanamycin and DEX significantly decreased the inflammatory responses in CTNNAL1-deficient HBE cells than DEX monotherapy. SIGNIFICANCE: Our study corroborates that CTNNAL1 deficiency induced aggravated airway inflammation and rendered insensitivity to glucocorticoids via triggering hsp90 signaling pathway.

Clinical Characteristics and In Silico Analysis of Cystinuria Caused by a Novel SLC3A1 Mutation.

Cystinuria is a genetically inherited disorder of renal and intestinal transport, featured as a high concentration of cystine in the urine. Cumulative cystine in urine would cause the formation of kidney stones, which further leads to renal colic and dysfunction. Gene screens have found that mutations in SLC3A1 or SLC7A9 gene are responsible for most cases of cystinuria, for encoding defective cystine transporters. Here, we presented the genotypic and phenotypic characteristics of one unique case of a three-generation Chinese family. The proband developed severe urolithiasis combined with renal damage. The radiography and computed tomography (CT) scan showed calculus in the left pelvic kidney. Postoperative stone analysis revealed that the stones were mainly composed of cystine. Therefore, to explore its pathogenesis, next-generation Whole Exome Sequencing (WES) and Sanger sequencing identify the proband mutated gene of the proband's family. In this article, we reported novel compound heterozygous mutations (c.818G>A and c.1011G>A) of the SLC3A1 gene in a 5-year-old child suffering from a cystine stone from a three-generation family. Bioinformatic analysis was used to predict the pathogenicity and conservation of the target mutation. Conservative sequence and evolutionary conservation analysis indicated that cystine273 and proline337 were highly conserved among species, and both mutations listed here (Cys273Tyr and Pro337Pro) were pathogenic. To conclude, our study expands the phenotypic and genotypic spectrum of SLC3A1 and indicates that genetic screening should be considered in the clinic to provide more effective and precise treatment for cystinuria.

Epithelial-mesenchymal transition in organ fibrosis development: current understanding and treatment strategies.

Organ fibrosis is a process in which cellular homeostasis is disrupted and extracellular matrix is excessively deposited. Fibrosis can lead to vital organ failure and there are no effective treatments yet. Although epithelial-mesenchymal transition (EMT) may be one of the key cellular mechanisms, the underlying mechanisms of fibrosis remain largely unknown. EMT is a cell phenotypic process in which epithelial cells lose their cell-to-cell adhesion and polarization, after which they acquire mesenchymal features such as infiltration and migration ability. Upon injurious stimulation in different organs, EMT can be triggered by multiple signaling pathways and is also regulated by epigenetic mechanisms. This narrative review summarizes the current understanding of the underlying mechanisms of EMT in fibrogenesis and discusses potential strategies for attenuating EMT to prevent and/or inhibit fibrosis. Despite better understanding the role of EMT in fibrosis development, targeting EMT and beyond in developing therapeutics to tackle fibrosis is challenging but likely feasible.

OGG1 in Lung-More than Base Excision Repair.

As the organ executing gas exchange and directly facing the external environment, the lungs are challenged continuously by various stimuli, causing the disequilibration of redox homeostasis and leading to pulmonary diseases. The breakdown of oxidants/antioxidants system happens when the overproduction of free radicals results in an excess over the limitation of cleaning capability, which could lead to the oxidative modification of macromolecules including nucleic acids. The most common type of oxidative base, 8-oxoG, is considered the marker of DNA oxidative damage. The appearance of 8-oxoG could lead to base mismatch and its accumulation might end up as tumorigenesis. The base 8-oxoG was corrected by base excision repair initiated by 8-oxoguanine DNA glycosylase-1 (OGG1), which recognizes 8-oxoG from the genome and excises it from the DNA double strand, generating an AP site for further processing. Aside from its function in DNA damage repairment, it has been reported that OGG1 takes part in the regulation of gene expression, derived from its DNA binding characteristic, and showed impacts on inflammation. Researchers believe that OGG1 could be the potential therapy target for relative disease. This review intends to make an overall summary of the mechanism through which OGG1 regulates gene expression and the role of OGG1 in pulmonary diseases.

Flexible and Highly Conductive Textiles Induced by Click Chemistry for Sensitive Motion and Humidity Monitoring.

To date, multifunctional sensors have aroused widespread concerns owing to their vital roles in the healthcare area. However, there are still significant challenges in the fabrication of functionalized integrated devices. In this work, hydrophobic-hydrophilic patterns are constructed on polyester-spandex-blended knitted fabric surface by the chemical click method, enabling accurate deposition of functionalized materials for sensitive and stable motion and humidity sensing. Representatively, a conductive silver nanowire (Ag NW) network was deliberately deposited on only the designated hydrophilic fabric surface to realize accurate, repeatable, and stable motion sensing. Such a Ag NWs sensor recorded a low electrical resistance (below 60 Ω), stable resistance cycling response (over 2000 cycles), and fast response time to humidity (0.46 s) during the sensing evaluation. In addition to experimental sensing, real human motions, such as mouth-opening and joint-flexing (wrist and neck), could also be detected using the same sensor. Similar promising outputs were also obtained over the humidity sensor fabricated over the same chemical click method, except the sensing material was replaced with polydopamine-modified carboxylated carbon nanotubes. The resultant sensor exhibits excellent sensitivity to not only experimentally adjusted environment humidity but also to the moisture content of breath and skin during daily activities. On top of all these, both sensors were fabricated over highly flexible fabric that offers high wearability, promising great application potential in the field of healthcare monitoring.

The Role of DNA Damage and Repair in Idiopathic Pulmonary Fibrosis.

The mortality rate of idiopathic pulmonary fibrosis (IPF) increases yearly due to ineffective treatment. Given that the lung is exposed to the external environment, it is likely that oxidative stress, especially the stimulation of DNA, would be of particular importance in pulmonary fibrosis. DNA damage is known to play an important role in idiopathic pulmonary fibrosis initiation, so DNA repair systems targeting damage are also crucial for the survival of lung cells. Although many contemporary reports have summarized the role of individual DNA damage and repair pathways in their hypotheses, they have not focused on idiopathic pulmonary fibrosis. This review, therefore, aims to provide a concise overview for researchers to understand the pathways of DNA damage and repair and their roles in IPF.

Underwater, Multifunctional Superhydrophobic Sensor for Human Motion Detection.

Superhydrophobic conductive materials have received a great amount of interest due to their wide applications in oil-water separation, electrically driven smart surface, electromagnetic shielding, and body motion detection. Herein, a highly conductive superhydrophobic cotton cloth is prepared by a facile method. A layer of polydopamine/reduced graphene oxide (PDA/rGO) was first coated on the cotton fabric, and then copper nanoparticles were in situ grown on the prepared surface. After further modification with stearic acid (STA), the wettability of the cotton surface changed from superhydrophilic to superhydrophobic (water contact angle (WCA) = 153°). The electrical conductivity of the PDA/rGO/Cu/STA cotton is as high as 6769 S·m-1, while the stearic acid effectively protects Cu NPs from oxidation. As a result, the superhydrophobic PDA/rGO/Cu/STA cotton has shown excellent electrical stability and can be used in detecting human motions in both ambient and underwater conditions. The sensor can recognize human motion from air into water and other underwater activities (e.g., underwater bending, stretching, and ultrasound). This multifunctional cotton device can be used as an ideal sensor for underwater intelligent devices and provides a basis for further research.