Objective:To study the clinical manifestations and genetic characteristics of neonatal-onset primary mitochondrial disease (PMD) caused by nuclear gene mutations.Methods:From May 2020 to March 2022, the clinical data, genetic results and follow-up information of neonates with PMD admitted to the Department of Neonatology of our two hospitals were retrospectively analyzed.Results:A total of 4 patients were enrolled, all with hyperlactatemia and metabolic acidosis. In case 1, the fetal cranial MRI showed agenesis of corpus callosum. In case 2, echocardiography after birth indicated hypertrophic cardiomyopathy. Whole exome sequencing found the following mutations: EARS2 nuclear gene c.1294C>T and c.971G>T variants, COA6 nuclear gene c.411_412insAAAG variant, ACAD9 nuclear gene c.1278+1G>A and c.895A>T variants, FOXRED1 nuclear gene c.1054C>T and c.3dup variants. Mitochondrial second-generation sequencing and multiplex ligation-dependent probe amplification showed no abnormalities. Cases 1 and 3 died during the neonatal period. Case 2 died at 2-year-and-2-month of age. Case 4 was followed up to 1 year of age with developmental delay.Conclusions:The main phenotypes of neonatal-onset PMD caused by nuclear gene mutations are hyperlactatemia, refractory metabolic acidosis and cardiomyopathy, which have a poor prognosis. Proactive genetic tests are helpful for early diagnosis.

Objective:To observe the effects of Xiaoqinglong Decoction and Qingqi Huatan Pills on interleukin-1β(IL-1β)-induced mucushypersecretion model of human airway epithelial H292 cellsand related molecules of nuclear factor-κB/microRNA-494 (NF-κB/miR-494) signaling pathway, and to explore the mechanism of the two medicines in improving pathological airway mucus.Methods:Methyl thiazolyl tetrazolium (MTT) colorimetric method was used to detect the effects of different concentrations of Xiaoqinglong Decoction and Qingqi Huatan Pills on the activity of H292 cellsinduced by IL-1β, and the appropriate concentration was selected for subsequent experiments. Cells were randomly divided into blank group, IL-1β model group (5 μg/L IL-1β), NF-κB inhibitor pyrrolidinedithiocarbamate (PDTC) group (5 μg/L IL-1β+100 μmol/L PDTC), Xiaoqinglong Decoction (5 μg/L IL-1β+1 000 mg/L Xiaoqinglong Decoction) and Qingqi Huatan Pill group (5 μg/L IL-1β+1 000 mg/L Qingqi Huatan Pills). 5 μg/L IL-1β was used to induce H292 cells for 24 hours to establish a model of airway epithelial mucus hypersecretion. Enzyme linked immunosorbent assay (ELISA) method was used to detect the levels of mucin 5AC (MUC5AC), tumor necrosis factor-α (TNF-α) and IL-8 and the synthesis of intracellular MUC5AC and cystic fibrosis transmembrane conductance regulator (CFTR). Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression levels of MUC5AC mRNA, CFTR mRNA, miR-494. Western blotting was used to detect protein expression of key proteins (p65) and NF-κB inhibitors (IκB) in NF-κB signaling pathway.Results:Xiaoqinglong Decoction and Qingqi Huatan Pills with the concentration of 1 000 mg/L were selected for the follow-up experiment. Compared with the blank group, the levels of MUC5AC, TNF-α and IL-8 were significantly increased in the model group, intracellular MUC5AC protein content and mRNA expression were also significantly increased, intracellular CFTR protein content and mRNA expression were significantly decreased, and intracellular p65 protein expression was significantly up-regulated, the expression of IκB protein was significantly down-regulated, and the expression of miR-494 was significantly increased. Compared with the model group, the levels of MUC5AC, TNF-α and IL-8 were significantly reduced in PDTC group, Xiaoqinglong Decoction group and Qingqi Huatan Pill group, intracellular MUC5AC protein content and mRNA expression were also significantly decreased, and intracellular p65 protein expression was significantly down-regulated, and IκB protein expression was significantly up-regulated, miR-494 expression was significantly reduced. Intracellular CFTR protein content and mRNA expression were significantly increased in both PDTC group and Qingqi Huatan Pill group. Compared with the PDTC group, the level of TNF-α in the Xiaoqinglong Decoction group was significantly increased (ng/L: 22.77±3.14 vs. 11.09±3.37, P < 0.05), the content and mRNA expression of CFTR and IκB protein expression was significantly decreased [CFTR protein (ng/L): 97.38±6.62 vs. 227.04±19.48, CFTR mRNA (2 -ΔΔCt): 0.99±0.08 vs. 1.21±0.08, IκB/β-actin: 1.69±0.11 vs. 2.00±0.18, all P < 0.05], the level of TNF-α in Qingqi Huatan Pill group was significantly higher (ng/L: 19.08±3.71 vs. 11.09±3.37, P < 0.05). Compared with Xiaoqinglong Decoction group, the protein content and mRNA expression of CFTR and IκB protein expression in Qingqi Huatan Pill group were significantly increased [CFTR protein (ng/L) : 235.01±22.71 vs. 97.38±6.62, CFTR mRNA(2 -ΔΔCt): 1.32±0.15 vs. 0.99±0.08, IκB/β-actin: 1.94±0.16 vs. 1.69±0.11, all P < 0.05]. Conclusions:The effect of Xiaoqinglong Decoctionin improving the hypersecretion of mucus in the airway epithelium may be related to the inhibition of NF-κB/miR-494 inflammatory signal-mediated MUC5AC hypersecretion, while the effect of Qingqi Huatan Pills may be related to the inhibition of NF-κB/miR-494 inflammatory signal-mediated MUC5AC hypersecretion and CFTR dysfunction. Therefore, the difference in the mechanism of the two treatments of airway pathological mucus is mainly in the regulation of CFTR mRNA and protein.