Falasca Laura, Mija Cosmina, Sberna Giuseppe, Francalancia Massimo, Meschi Silvia, Mazzotta Valentina, Girardi Enrico, Antinori Andrea, Maggi Fabrizio, Bordi Licia
Laboratory of Electron Microscopy, National Institute for Infectious Diseases Lazzaro Spallanzani-IRCCS, 00149 Rome, Italy.
Laboratory of Virology and Biosafety Laboratories, National Institute for Infectious Diseases Lazzaro Spallanzani-IRCCS, 00149 Rome, Italy.
Int J Mol Sci. 2025 Mar 18;26(6):2718. doi: 10.3390/ijms26062718.
The mpox virus (MPXV) Clade IIb outbreak in 2022 was the biggest one ever to occur outside Africa, causing different types of clinical symptoms and levels of disease severity. There is no currently approved treatment for mpox, but Tecovirimat has proven effective against known orthopoxviruses in several animal models and Vero cell cultures. Since serious complications, including lung involvement, have been reported, especially in immunocompromised people, we investigated the effects of MPXV infection on the in vitro model of lung airway epithelium (Calu-3 cell line) and examined MPXV replication kinetic and related ultrastructural changes, also performing dose-response studies to measure Tecovirimat antiviral activity. Our results highlighted an active replication of MPXV in Calu-3 cells linked to mitochondrial structural modifications with perinuclear relocation and the formation of cytoplasmic vacuoles. Treatment with Tecovirimat consistently reduced viral replication both in supernatants (81%) and inside cells (77%) and ultimately stopped viral infectivity (92% of cytopathic effect reduction) after 48 h of infection. Drug administration inhibited the final wrapping of mature viral particles, causing extensive cytoplasmic vacuolation. Our results demonstrated Tecovirimat's in vitro effectiveness against MPXV at the nanomolar concentration on Calu-3 cells. This suggests a potential rationale for using this drug for patients with mpox severe disease and lung involvement.
2022年猴痘病毒（MPXV）IIb分支疫情是非洲以外发生的规模最大的一次，引发了不同类型的临床症状和疾病严重程度。目前尚无批准用于治疗猴痘的药物，但在多个动物模型和Vero细胞培养物中，特考韦瑞已被证明对已知正痘病毒有效。由于已报告出现包括肺部受累在内的严重并发症，尤其是在免疫功能低下人群中，我们研究了MPXV感染对肺气道上皮体外模型（Calu-3细胞系）的影响，检测了MPXV复制动力学及相关超微结构变化，还开展了剂量反应研究以测定特考韦瑞的抗病毒活性。我们的结果突出显示了MPXV在Calu-3细胞中的活跃复制，这与线粒体结构改变有关，线粒体发生核周移位并形成细胞质空泡。用特考韦瑞治疗可持续减少上清液（81%）和细胞内（77%）的病毒复制，并在感染48小时后最终阻止病毒感染性（细胞病变效应降低92%）。给药抑制了成熟病毒颗粒的最终包裹，导致广泛的细胞质空泡化。我们的结果证明了特考韦瑞在纳摩尔浓度下对Calu-3细胞中的MPXV具有体外有效性。这为将该药物用于患有严重猴痘疾病且肺部受累的患者提供了潜在依据。
