Shuchi Sarjana, Ratho Radha Kanta, Mohi Gursimran Kaur, Kumar Angurana Suresh, Sarkar Subhabrata, Jangra Isheeta
Department of Virology, Post Graduate Institute of Medical Education and Research, Chandigarh, India.
Department of Paediatrics, Post Graduate Institute of Medical Education and Research, Chandigarh, India.
J Med Virol. 2023 Mar;95(3):e28666. doi: 10.1002/jmv.28666.
The study was planned to carry out the molecular characterization of the respiratory syncytial virus (RSV) circulating strains and to elucidate the gene expression of autophagy and mammalian target of rapamycin (mTOR) signaling pathways in children with acute lower respiratory tract infection (ALRTI). Nasopharyngeal aspirate (NPA) samples (n = 145) from children suffering from ALRTI were subjected to the detection of RSV. Of them, 31 RSV positive strains were subjected for sequencing. Semi-quantitative gene expression analysis for mTOR signaling and autophagy pathway genes was performed in respiratory tract epithelial cells using 25 RSV positive cases, and 10 age and sex matched healthy control subjects. Five representative genes were selected for each pathway and subjected to SYBR green real-time polymerase chain reaction. RSV was positive in 69 (47.6%) samples and the representative (n = 31) RSV strains belonged to RSV-A. Thirty-one strains of RSV-A on phylogenetic analysis clustered with the novel ON1 genotype having 72 bp nucleotide duplicationby targeting the ecto-domain portion of the G gene. Further, the stains belonged to lineage 1 (51.6%), followed by lineage 3 (29%) and lineage 2 (19.4%). Autophagy gene expression analysis revealed significant upregulation in NPC1 and ATG3 autophagy genes. mTOR, AKT1, and TSC1 genes of the mTOR pathway were significantly downregulated in RSV positive patients. Thus, RSV infection inducing autophagy pathway genes (NPC1 and ATG3) and suppressing mTOR signaling pathway genes (AKT1, mTOR, and TSC1) to possibly evade the host immune system through dysregulating these pathways for its way of survival within the host.
本研究旨在对呼吸道合胞病毒（RSV）流行毒株进行分子特征分析，并阐明急性下呼吸道感染（ALRTI）患儿自噬及雷帕霉素哺乳动物靶蛋白（mTOR）信号通路的基因表达情况。对145例患ALRTI患儿的鼻咽抽吸物（NPA）样本进行RSV检测。其中31株RSV阳性毒株进行测序。利用25例RSV阳性病例及10例年龄和性别匹配的健康对照受试者的呼吸道上皮细胞，对mTOR信号通路和自噬通路基因进行半定量基因表达分析。为每条通路选择5个代表性基因，进行SYBR Green实时聚合酶链反应。69份（47.6%）样本RSV呈阳性，31株代表性RSV毒株属于RSV-A。系统发育分析显示，31株RSV-A毒株通过靶向G基因的胞外结构域部分，与具有72 bp核苷酸重复的新型ON1基因型聚类。此外，这些毒株属于1系（51.6%），其次是3系（29%）和2系（19.4%）。自噬基因表达分析显示NPC1和ATG3自噬基因显著上调。RSV阳性患者的mTOR通路中的mTOR、AKT1和TSC1基因显著下调。因此，RSV感染诱导自噬通路基因（NPC1和ATG3）并抑制mTOR信号通路基因（AKT1,mTOR和TSC1），可能通过失调这些通路来逃避宿主免疫系统，从而在宿主体内生存。
