Karim Loukmane, Lin Chih-Ru, Kosmider Beata, Criner Gerard, Marchetti Nathaniel, Bolla Sudhir, Bowler Russell, Bahmed Karim
Department of Microbiology, Immunology, and Inflammation, Temple University, Philadelphia, PA 19140, USA.
Center for Inflammation and Lung Research, Temple University, Philadelphia, PA 19140, USA.
Biomedicines. 2022 Jun 24;10(7):1497. doi: 10.3390/biomedicines10071497.
Pulmonary emphysema is characterized by airspace enlargement and the destruction of alveoli. Alveolar type II (ATII) cells are very abundant in mitochondria. OXPHOS complexes are composed of proteins encoded by the mitochondrial and nuclear genomes. Mitochondrial 12S and 16S rRNAs are required to assemble the small and large subunits of the mitoribosome, respectively. We aimed to determine the mechanism of mitoribosome dysfunction in ATII cells in emphysema. ATII cells were isolated from control nonsmokers and smokers, and emphysema patients. Mitochondrial transcription and translation were analyzed. We also determined the miRNA expression. Decreases in ND1 and UQCRC2 expression levels were found in ATII cells in emphysema. Moreover, nuclear NDUFS1 and SDHB levels increased, and mitochondrial transcribed ND1 protein expression decreased. These results suggest an impairment of the nuclear and mitochondrial stoichiometry in this disease. We also detected low levels of the mitoribosome structural protein MRPL48 in ATII cells in emphysema. Decreased 16S rRNA expression and increased 12S rRNA levels were observed. Moreover, we analyzed miR4485-3p levels in this disease. Our results suggest a negative feedback loop between miR-4485-3p and 16S rRNA. The obtained results provide molecular mechanisms of mitoribosome dysfunction in ATII cells in emphysema.
肺气肿的特征是气腔扩大和肺泡破坏。肺泡II型(ATII)细胞的线粒体非常丰富。氧化磷酸化复合物由线粒体和核基因组编码的蛋白质组成。线粒体12S和16S rRNA分别是组装线粒体核糖体小亚基和大亚基所必需的。我们旨在确定肺气肿中ATII细胞线粒体核糖体功能障碍的机制。从对照非吸烟者、吸烟者和肺气肿患者中分离出ATII细胞。分析线粒体转录和翻译情况。我们还测定了miRNA表达。在肺气肿的ATII细胞中发现ND1和UQCRC2表达水平降低。此外,细胞核中的NDUFS1和SDHB水平升高,而线粒体转录的ND1蛋白表达降低。这些结果表明该疾病中核与线粒体化学计量存在损伤。我们还在肺气肿的ATII细胞中检测到线粒体核糖体结构蛋白MRPL48水平较低。观察到16S rRNA表达降低和12S rRNA水平升高。此外,我们分析了该疾病中miR4485 - 3p的水平。我们的结果表明miR - 4485 - 3p与16S rRNA之间存在负反馈环。所获得的结果提供了肺气肿中ATII细胞线粒体核糖体功能障碍的分子机制。