Background Pneumoconiosis is the most serious occupational disease in China, among which silicosis accounts for more than 50%. microRNA (miRNA) plays an important role in the occurrence process of silicosis fibrosis, but the mechanism of it has not been fully clarified yet. Objective To explore the molecular mechanism by which miR-411-3p modulates the ubiquitination degradation of SMAD specific E3 ubiquitin protein ligase (SMURF) 2/Smad7, thereby suppressing epithelial-mesenchymal transition (EMT) in mouse alveolar type II epithelial cells and counteracting silica-induced pulmonary fibrosis. Methods Twenty-four 8-week-old SPF male C57BL/6J mice were randomly divided into four groups: Control group, silica group, silica +miR-411-3p agomir-NC group, and silica +miR-411-3p agomir group, with 6 mice in each group. Silicosis model was prepared by a one-time bronchial infusion of silicon dioxide (SiO₂) (200 mg·mL^-1, 50 μL). In vitro MLE-12 cells were divided into (1) control group and SiO₂ group, (2) SiO₂+negative control siRNA (siRNA-NC) group and SiO₂+Smurf2 gene silencing (si-Smurf2) group, (3) SiO₂+solvent (DMSO) group and SiO₂+protease inhibitor (MG132) group, (4) mutant sequence plasmid (Mut)+miR-411-3p mimic control (miR-NC) group, Mut+miR-411-3p mimic group, wild sequence plasmid (Wt)+miR-NC group, and Wt+miR-411-3p mimic group, (5) SiO₂+miR-NC group and SiO₂+miR-411-3p mimic group. The pathological morphology and collagen deposition of lung tissue were observed after staining. Detection of miR-411-3p and proteins was conducted by real-time fluorescent quantitative PCR and Western blot. The binding of SMURF2 to Smad7 protein and Smad7 to ubiquitin (Ub) were detected by co-immunoprecipitation (Co-IP) method. Dual-luciferase reporter gene assay was adopted to verify the regulatory effect of miR-411-3p on Smurf2. Results In the SiO₂-induced MLE-12 cells, compared to the control group, the SiO₂-treated group showed significantly upregulated expressions of N-cadherin (N-Cad), collagen I (CoL I), SMURF2, transforming growth factor-β1 (TGF-β1), and phosphorylated Smad2/3 (p-Smad2/3). In contrast, the expressions of E-cadherin (E-Cad), Smad7, and miR-411-3p were significantly downregulated (P<0.05). The dual-luciferase reporter gene assay revealed a regulatory effect of miR-411-3p on Smurf2 (P<0.05). Meanwhile, in the MLE-12 cells induced by SiO₂, the miR-411-3p mimic down-regulated the protein expressions of SMURF2, N-Cad, CoL I, TGF-β1, and p-Smad2/3, while up-regulated the protein expressions of E-Cad and Smad7 (P<0.05). The silenced Smurf2 gene inhibited the expressions of N-Cad, CoL I, and p-Smad2/3 proteins, while promoted the expressions of E-Cad and Smad7 proteins in the MLE-12 cells (P<0.05). The Co-IP results showed that the binding of SMURF2 to Smad7 was enhanced, and the ubiquitin binding ability of Smad7 was enhanced in the SiO₂ group. In the lung tissue of mice, the results of pathological observation with hematoxylin-eosin (HE) and sirius red (VG) staining showed that compared with the agomir-NC, the lesion was relieved in the lung tissue of the miR-411-3p agomir group. Meanwhile, the expressions of SMURF2, N-Cad, CoL I, TGF-β1, and p-Smad2/3 were significantly down-regulated, while the expressions of E-Cad and Smad7 were significantly up-regulated (P<0.05). Conclusion MiR-411-3p alleviates the EMT of alveolar type II epithelial cells and antagonizes silicosis fibrosis progression in mice by inhibiting SMURF2-mediated ubiquitination and degradation of Smad7.

Myocarditis is an inflammatory disease of myocardium caused by a variety of factors.The most common etiology is enterovirus, followed by respiratory viruses, especially the new coronaviruses, mycoplasma, rickettsia, and toxoplasma, etc.The probability of arrhythmia is relatively high in myocarditis due to increased myocardial susceptibility, and its type may be suggestive of disease progression and prognosis.Electrophysiological changes in the cardio-myocytes are observed by electrocardiography and ambulatory electrocardiography.Echocardiography and cardiac magnetic resonance are used to detect specific changes in the internal structure of the myocardium and left ventricular systolic function and to assist in the diagnosis.For the treatment of myocarditis, in addition to general treatment, according to the needs of the condition, intravenous immunoglobulin, glucocorticoids, and receptor antagonists of some cytokines can be used.The prognosis of pediatric myocarditis is related to the type of myocarditis, the speed of progression, the degree of myocardial damage, the electrophysiological changes and the structural changes of the heart.

This paper reported a case of drug eruption in a male patient with first-episode schizophrenia. The patient received ziprasidone monotherapy， and experienced post-treatment remission of schizophrenic symptoms， while accompanied by drug eruption with fever and elevated white blood cell count. Even with antiallergic treatment， the eruption did not subside without discontinuation of ziprasidone， whereas the eruption resolved after discontinuation of ziprasidone. This case suggested that individual allergy history should be taken into account during the use of ziprasidone， and timely intervention of adverse skin reactions was essential to prevent the development of severe drug eruption.