Although chronic intermittent hypoxia- (IH-) induced myocardial apoptosis is an established pathophysiological process resulting in a poor prognosis for patients with obstructive sleep apnea syndrome, its underlying mechanism remains unclear. This study is aimed at exploring the role of makorin ring finger protein 1 (MKRN1) in IH-induced myocardial apoptosis and elucidating its molecular activity. First, the GSE2271 dataset was downloaded from the Gene Expression Omnibus database to identify the differentially expressed genes. Then, an SD rat model of IH, together with rat cardiomyocyte H9C2 and human cardiomyocyte AC16 IH models, was constructed. TUNEL, Western blot, and immunohistochemistry assays were used to detect cell apoptosis. Dihydroethidium staining was conducted to analyze the concentration of reactive oxygen species. In addition, RT-qPCR, Western blot, and immunohistochemistry were performed to measure the expression levels of MKRN1 and p21. The direct interaction between MKRN1 and p21 was determined using coimmunoprecipitation and ubiquitination analysis. MKRN1 expression was found to be downregulated in IH rat myocardial tissues as well as in H9C2 and AC16 cells. Upregulated expression of MKRN1 in H9C2 and AC16 cells alleviated the IH-induced reactive oxygen species production and cell apoptosis. Mechanistically, MKRN1 promoted p21 protein ubiquitination and the proteasome pathway degradation to negatively regulate p21 expression. Thus, MKRN1 regulates p21 ubiquitination to prevent IH-induced myocardial apoptosis.

A variety of studies has linked vasoactive intestinal peptide (VIP) to idiopathic pulmonary arterial hypertension (IPAH). In this study, we investigated the correlation between VIP gene variants and IPAH in Chinese population. A total of 81 consecutive unrelated patients diagnosed as IPAH from 2006 to 2008 and 250 controls were included in the study. VIP gene variants were screened by direct sequencing, and VIP serum level was determined by enzyme-linked immunosorbent assay. Clinical and hemodynamic data of all patients were also obtained. The variant g.8129T-->C in exon 7 was found to be the only variant in the coding region of VIP gene with a significantly higher frequency in patients (40.7%) than in control samples (15.2%). Moreover, there was marked difference in VIP serum level and hemodynamic data between IPAH patients with and without the variant. The variant g.8129T-->C in exon 7 of VIP gene was correlated with the clinical phenotype of lower VIP serum level, higher mean pulmonary artery pressure and pulmonary vascular resistance in patients with IPAH comparing to those in patients without this variant. The VIP gene variant g.8129T-->C may be one of the risk factors in the pathogenesis of IPAH.

Checkpoint inhibitor pneumonitis (CIP) is a relatively rare adverse event and a potential cause of death in patients treated with immune checkpoint inhibitors (ICIs). Because the symptoms and signs are nonspecific, the diagnosis of CIP is challenging. Additionally, compared with the biomarkers that can monitor the effect of ICIs, there is less research evaluating markers to monitor CIP. We report a case of CIP induced by camrelizumab in a patient with advanced non-small-cell lung cancer, in which the fractional exhaled nitric oxide levels showed obvious increases. Fractional exhaled nitric oxide may have the potential to monitor the condition of airway inflammation in patients using ICIs.