DEC1 is involved in circadian rhythm disruption-exacerbated pulmonary fibrosis.

BACKGROUND: The alveolar epithelial type II cell (AT2) and its senescence play a pivotal role in alveolar damage and pulmonary fibrosis. Cell circadian rhythm is strongly associated with cell senescence. Differentiated embryonic chondrocyte expressed gene 1 (DEC1) is a very important circadian clock gene. However, the role of DEC1 in AT2 senescence and pulmonary fibrosis was still unclear. RESULTS: In this study, a circadian disruption model of light intervention was used. It was found that circadian disruption exacerbated pulmonary fibrosis in mice. To understand the underlying mechanism, DEC1 levels were investigated. Results showed that DEC1 levels increased in lung tissues of IPF patients and in bleomycin-induced mouse fibrotic lungs. In vitro study revealed that bleomycin and TGF-ß1 increased the expressions of DEC1, collagen-I, and fibronectin in AT2 cells. Inhibition of DEC1 mitigated bleomycin-induced fibrotic changes in vitro and in vivo. After that, cell senescence was observed in bleomycin-treated AT2 cells and mouse models, but these were prevented by DEC1 inhibition. At last, p21 was confirmed having circadian rhythm followed DEC1 in normal conditions. But bleomycin disrupted the circadian rhythm and increased DEC1 which promoted p21 expression, increased p21 mediated AT2 senescence and pulmonary fibrosis. CONCLUSIONS: Taken together, circadian clock protein DEC1 mediated pulmonary fibrosis via p21 and cell senescence in alveolar epithelial type II cells.

PM2.5 exposure-induced senescence-associated secretory phenotype in airway smooth muscle cells contributes to airway remodeling.

Fine particulate matter (PM2.5) has been linked to increased severity and incidence of airway diseases, especially chronic obstructive pulmonary disease (COPD) and asthma. Airway remodeling is an important event in both COPD and asthma, and airway smooth muscle cells (ASMCs) are key cells which directly involved in airway remodeling. However, it was unclear how PM2.5 affected ASMCs. This study investigates the effects of PM2.5 on airway smooth muscle and its mechanism. We first showed that inhaled particulate matter was distributed in the airway smooth muscle bundle, combined with increased airway smooth muscle bundle and collagen deposition in vivo. Then, we demonstrated that PM2.5 induced up-regulation of collagen-I and alpha-smooth muscle actin (α-SMA) expression in rat and human ASMCs in vitro. Next, we found PM2.5 led to rat and human ASMCs senescence and exhibited senescence-associated secretory phenotype (SASP) by autophagy-induced GATA4/TRAF6/NF-κB signaling, which contributed to collagen-I and α-SMA synthesis as well as airway smooth muscle remodeling. Together, our results provided evidence that SASP induced by PM2.5 in airway smooth muscle cells prompted airway remodeling.

Epigenetically upregulated NSUN2 confers ferroptosis resistance in endometrial cancer via m5C modification of SLC7A11 mRNA.

Endometrial cancer (EC) is a prevalent gynecological malignancy worldwide, and 5-methylcytosine (m5C) modification of mRNA is a crucial epigenetic modification associated with the development and occurrence of several cancers. However, the precise function of m5C modification in EC remains elusive. This study aimed to investigate the expression and clinical significance of the primary m5C modification writer, NSUN2, in EC. Our findings indicated that NSUN2 exhibited a substantial up-regulation in EC as a result of an epigenetic augmentation in H3K4me3 levels within the promoter region, which was triggered by the down-regulation of KDM5A. Moreover, gain- and loss-of-function experiments revealed the role of NSUN2 in enhancing m5C modification of mRNA, thereby promoting EC cell proliferation. RNA bisulfite sequencing and transcriptomic sequencing were employed to elucidate the involvement of NSUN2 in the regulation of ferroptosis. Subsequent in vitro experiments confirmed that the knockdown of NSUN2 significantly up-regulated the levels of lipid peroxides and lipid ROS in EC cells, thereby augmenting the susceptibility of EC to ferroptosis. Mechanistically, NSUN2 stimulated the m5C modification of SLC7A11 mRNA, and the m5C reader YBX1 exhibited direct recognition and binding to the m5C sites on SLC7A11 mRNA via its internal cold shock domain (CSD), leading to an increase in SLC7A11 mRNA stability and elevated levels of SLC7A11. Additionally, rescue experiments showed that NSUN2 functioned as a suppressor of ferroptosis, which was dependent on SLC7A11. Overall, targeting the NSUN2/SLC7A11 axis inhibited tumor growth by increasing lipid peroxidation and ferroptosis of EC cells both in vitro and in vivo. Therefore, our study provides new insight into the role of NSUN2, suggesting that NSUN2 may serve as a prognostic biomarker and therapeutic target in patients with EC.

BMAL1/p53 mediating bronchial epithelial cell autophagy contributes to PM2.5-aggravated asthma.

BACKGROUND: Fine particulate matter (PM2.5) is associated with increased incidence and severity of asthma. PM2.5 exposure disrupts airway epithelial cells, which elicits and sustains PM2.5-induced airway inflammation and remodeling. However, the mechanisms underlying development and exacerbation of PM2.5-induced asthma were still poorly understood. The aryl hydrocarbon receptor nuclear translocator-like protein 1 (BMAL1) is a major circadian clock transcriptional activator that is also extensively expressed in peripheral tissues and plays a crucial role in organ and tissue metabolism. RESULTS: In this study, we found PM2.5 aggravated airway remodeling in mouse chronic asthma, and exacerbated asthma manifestation in mouse acute asthma. Next, low BMAL1 expression was found to be crucial for airway remodeling in PM2.5-challenged asthmatic mice. Subsequently, we confirmed that BMAL1 could bind and promote ubiquitination of p53, which can regulate p53 degradation and block its increase under normal conditions. However, PM2.5-induced BMAL1 inhibition resulted in up-regulation of p53 protein in bronchial epithelial cells, then increased-p53 promoted autophagy. Autophagy in bronchial epithelial cells mediated collagen-I synthesis as well as airway remodeling in asthma. CONCLUSIONS: Taken together, our results suggest that BMAL1/p53-mediated bronchial epithelial cell autophagy contributes to PM2.5-aggravated asthma. This study highlights the functional importance of BMAL1-dependent p53 regulation during asthma, and provides a novel mechanistic insight into the therapeutic mechanisms of BMAL1. Video Abstract.

Blockade of phosphotyrosine pathways suggesting SH2 superbinder as a novel therapy for pulmonary fibrosis.

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive and irreversible fibrotic disease with high mortality. Currently, pirfenidone and nintedanib are the only approved drugs for IPF by the U.S. Food and Drug Administration (FDA), but their efficacy is limited. The activation of multiple phosphotyrosine (pY) mediated signaling pathways underlying the pathological mechanism of IPF has been explored. A Src homology-2 (SH2) superbinder, which contains mutations of three amino acids (AAs) of natural SH2 domain has been shown to be able to block phosphotyrosine (pY) pathway. Therefore, we aimed to introduce SH2 superbinder into the treatment of IPF. Methods: We analyzed the database of IPF patients and examined pY levels in lung tissues from IPF patients. In primary lung fibroblasts obtained from IPF patient as well as bleomycin (BLM) treated mice, the cell proliferation, migration and differentiation associated with pY were investigated and the anti-fibrotic effect of SH2 superbinder was also tested. In vivo, we further verified the safety and effectiveness of SH2 superbinder in multiple BLM mice models. We also compared the anti-fibrotic effect and side-effect of SH2 superbinder and nintedanib in vivo. Results: The data showed that the cytokines and growth factors pathways which directly correlated to pY levels were significantly enriched in IPF. High pY levels were found to induce abnormal proliferation, migration and differentiation of lung fibroblasts. SH2 superbinder blocked pY-mediated signaling pathways and suppress pulmonary fibrosis by targeting high pY levels in fibroblasts. SH2 superbinder had better therapeutic effect and less side-effect compare to nintedanib in vivo. Conclusions: SH2 superbinder had significant anti-fibrotic effects both in vitro and in vivo, which could be used as a promising therapy for IPF.

Splicing factor SRSF6 mediates pleural fibrosis.

Pleural fibrosis is defined as an excessive deposition of extracellular matrix that results in destruction of the normal pleural tissue architecture and compromised function. Tuberculous pleurisy, asbestos injury, and rheumatoid pleurisy are main causes of pleural fibrosis. Pleural mesothelial cells (PMCs) play a key role in pleural fibrosis. However, detailed mechanisms are poorly understood. Serine/arginine-rich protein SRSF6 belongs to a family of highly conserved RNA-binding splicing-factor proteins. Based on its known functions, SRSF6 should be expected to play a role in fibrotic diseases. However, the role of SRSF6 in pleural fibrosis remains unknown. In this study, SRSF6 protein was found to be increased in cells of tuberculous pleural effusions (TBPE) from patients, and decellularized TBPE, bleomycin, and TGF-ß1 were confirmed to increase SRSF6 levels in PMCs. In vitro, SRSF6 mediated PMC proliferation and synthesis of the main fibrotic protein COL1A2. In vivo, SRSF6 inhibition prevented mouse experimental pleural fibrosis. Finally, activated SMAD2/3, increased SOX4, and depressed miRNA-506-3p were associated with SRSF6 upregulation in PMCs. These observations support a model in which SRSF6 induces pleural fibrosis through a cluster pathway, including SRSF6/WNT5A and SRSF6/SMAD1/5/9 signaling. In conclusion, we propose inhibition of the splicing factor SRSF6 as a strategy for treatment of pleural fibrosis.

Bleomycin induced apical-basal polarity loss in alveolar epithelial cell contributes to experimental pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a fatal fibrosing interstitial lung disease with limited therapeutic options and a median survival of 3 years after diagnosis. Dysregulated epithelial regeneration is key event involved in initiating and sustaining IPF. The type II alveolar epithelial cells (AECIIs) play a crucial role for epithelial regeneration and stabilisation of alveoli. Loss of cell apical-basal polarity contributes to fibrosis. AECII has apical-basal polarity, but it is poorly understood whether AECII apical-basal polarity loss is involved in fibrosis. Bleomycin is a traditional inducer of pulmonary fibrosis. Here firstly we observed that bleomycin induced apical-basal polarity loss in cultured AECIIs. Next, cell polarity proteins lethal (2) giant larvae 1 (Lgl1), PAR-3A, aPKC and PAR-6B were investigated. We found bleomycin induced increases of Lgl1 protein and decreases of PAR-3A protein, and bleomycin-induced PAR-3A depression was mediated by increased-Lgl1. Then Lgl1 siRNA was transfected into AECIIs. Lgl1 siRNA prevented apical-basal polarity loss in bleomycin-treated AECIIs. At last, Lgl1-conditional knockout mice were applied in making animal models. Bleomycin induced pulmonary fibrosis, but this was attenuated in Lgl1-conditional knockout mice. Together, these data indicated that bleomycin mediated AECII apical-basal polarity loss which contributed to experimental pulmonary fibrosis. Inhibition of Lgl1 should be a potential therapeutic strategy for the disease.

Crosstalk between pleural mesothelial cell and lung fibroblast contributes to pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a specific form of chronic, progressive and fibrosing interstitial pneumonia of unknown cause. The main feature of IPF is a heterogeneous appearance with areas of sub-pleural fibrosis. However, the mechanism of sub-pleural fibrosis was poorly understood. In this study, our in vivo study revealed that pleural mesothelial cells (PMCs) migrated into lung parenchyma and localized alongside lung fibroblasts in sub-pleural area in mouse pulmonary fibrosis. Our in vitro study displayed that cultured-PMCs-medium induced lung fibroblasts transforming into myofibroblast, cultured-fibroblasts-medium promoted mesothelial-mesenchymal transition of PMCs. Furthermore, these changes in lung fibroblasts and PMCs were prevented by blocking TGF-ß1/Smad2/3 signaling with SB431542. TGF-ß1 neutralized antibody attenuated bleomycin-induced pulmonary fibrosis. Similar to TGF-ß1/Smad2/3 signaling, wnt/ß-catenin signaling was also activated in the process of PMCs crosstalk with lung fibroblasts. Moreover, inhibition of CD147 attenuated cultured-PMCs-medium induced collagen-I synthesis in lung fibroblasts. Blocking CD147 signaling also prevented bleomycin-induced pulmonary fibrosis. Our data indicated that crosstalk between PMC and lung fibroblast contributed to sub-pleural pulmonary fibrosis. TGF-ß1, Wnt/ß-catenin and CD147 signaling was involved in the underling mechanism.

Preparation and performance of a pH-sensitive cisplatin-loaded magnetic nanomedicine that targets tumor cells via folate receptor mediation.

The present study aimed to prepare cisplatin (CDDP)-loaded magnetic nanoparticles (MNPs), which target folate receptors via a pH-sensitive release system (FA­PEG­NH­N=MNPs­CDDP). This is of interest for the development of intelligent drug delivery systems that target tumors of the head and neck. The chemical coprecipitation method was used to prepare ferroferric oxide MNPs. These were modified with aldehyde sodium alginate complexed with the chemotherapeutic agent, CDDP on the surface of the nanoparticles. Double hydrazine­poly(ethylene glycol; PEG) was also prepared by attaching the carboxyl group of hydrazine­folate on one side of the double hydrazine­PEG, obtaining folate­hydrazine­PEG­diazenyl. This binds the aldehyde group of sodium alginic acid on the MNP to enclose CDDP, in order that it is sequestered within the carrier. This method obtained a pH­sensitive, FA­modified CDDP­loaded MNP (FA­PEG­NH­N=MNPs­CDDP), which acts as an intelligent tumor targeting drug delivery system. The mean size of the MNPs was ~10.2±1.5 nm, the mean hydrodynamic diameter detected by laser particle sizing instruments was 176.6±1.1 nm, and the ζ­potential was ­20.91±1.76 mV. The CDDP content was 0.773 mg/ml, the iron content was ~1.908 mg/ml and the maximum saturation magnetization was 16.3±0.2 emu/g. The current study produced a pH­sensitive FA­modified CDDP­loaded MNP that is stable and exhibits magnetic responsiveness, which releases CDDP in a low pH environment.

[Cochlear implant in patients with congenital malformation of the inner ear].

OBJECTIVE: To summarize the clinical experience with multi-channel cochlear implantation in patients with inner ear malformations and evaluate and the outcomes of speech rehabilitation. METHODS: A retrospective study was conducted in 295 patients receiving cochlear implantation from 1998 to 2007, including 25 patients with large vestibular aqueduct syndrome (LVAS), 9 with Modini malformation, and 5 with common cavity deformity. All the patients received the Nucleus24 cochlear implants. In LVAS cases, 4 had Nucleus 24R (ST) implants, 8 had Contuor implants, 10 had Contuor Advance, and the remaining cases used Nucleus24(M) straight-electrode implants. RESULTS: Severe gusher appeared in 3 cases of LVAS, and perilymph fluctuation were seen in other 15 cases. Four patients with Mondini malformation and 2 with common cavity malformation also experienced severe gusher, but the electrodes were inserted smoothly in all the patients without postoperative facial paralysis or cerebrospinal fluid leakage. The hearing threshold in these patients was similar to that in patients with normal cochlear structure. After speech rehabilitation for over 6 months, the abilities of speech discrimination and spoken language improved in all the cases in comparison with the preoperative lingual functions. CONCLUSION: Multi-channel cochlear implantation can be performed in patients with inner ear malformation, but should not be attempted in patients with poor cochlear and cochlear nerve development. A comprehensive pre-operative radiographic and audiological evaluation is essential.

[Cochlear implantation in patients with large vestibular aqueduct syndrome].

OBJECTIVE: To evaluate the hearing and speech recognition in patients with large vestibular aqueduct syndrome undergoing multi-channel cochlear implantation. METHODS: From 2005 to 2008, multi-channel cochlear implantation surgeries were performed in 22 patients with large vestibular aqueduct syndrome. All the patients received multi-channel cochlear implantation through transmastoid facial recess approach. The postoperative outcomes of the patients were compared with those of 22 patients with non-malformed cochlear. RESULTS: Severe gusher occurred in 3 cases during the implantation, and perilymph fluctuation was found in another 15 cases, with a rate of anomalies of 81.8%. All the electrodes were totally inserted into the cochlear, and no facial paralysis or cerebrospinal fluid leakage occurred after the operation. The hearing threshold in these patients was similar to that in patients with normal cochlear receiving the implantation. After speech rehabilitation for over 6 months, all the patients showed improved hearing and verbal ability. CONCLUSION: Multi-channel cochlear implantation can be performed in patients with large vestibular aqueduct syndrome, but preoperative hearing assessment and radiographic examinations should be performed.

[Effect of surgical reconstruction of congenital aural atresia via the mastoid antrum approach: analysis of 48 cases].

OBJECTIVE: To assess the effect of surgical reconstruction of congenital aural atresia via the mastoid antrum approach and investigate method for preventing postoperative atresia of the reconstructed aural canal. METHODS: From 2000 to 2008, aural canal reconstruction and tympanoplasty was performed via the mastoid antrum approach. In 48 patients with congenital aural atresia (54 ears, including 45 ears of type II, 9 ears of type III). All the patients were followed-up for 18 months to assess the therapeutic effect. RESULTS: The mastoid antrum was located uneventfully for all the 54 ears, all showing ossicular chain anomalies involving most frequently the malleus and the incus followed by the upper structures of the stapes. Facial nerve abnormalities were seen in 23 ears (42.6%). Hearing improvement to over 20 dB was achieved in 45 ears (83.3%) and to over 25 dB in 25 ears (46.2%) one year later. CONCLUSION: The mastoid antrum approach for surgical reconstruction of congenital aural atresia is safe and reliable. Maintenance of the width of the aural canal and prevention of lateral healing of the transplanted tympanic membrane are crucial in the treatment of congenital aural atresia.