Pneumonia is usually caused by a wide variety of pathogen infection. The underlying mechanism contributing to pneumonia remains elusive. Here, the role of microRNA-497-3p (miR-497-3p) was explored in bacterial pneumonia. The expression levels of miR-497-3p and procalcitonin (PCT) in patient serum were detected by real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. The interaction between miR-497-3p and PCT was further verified in A549 cell line. To further explore the role of miR-497-3p in pneumonia, mouse model of bacterial pneumonia was established via Sp TIGR4 strain (SpT4) infection. Subsequently, LV-miR-497-3p sponge was administrated in mice with bacterial pneumonia. The severity of pneumonia and inflammatory response were evaluated. Serum miR-497-3p and PCT levels increased in patients with bacterial pneumonia and miR-497-3p level positively corrected with the PCT level. The functional assay demonstrated that CALCA is the target of miR-497-3p in the A549 cell line. In mice with bacterial pneumonia, both miR-497-3p and PCT levels were upregulated after SpT4 infection. LV-miR-497-3p sponge administration attenuated pneumonia, accompanied with increasing gain of bodyweight and blood oxygen levels, as well as uninjured lungs. miR-497-3p inhibition attenuates the expression of C-reactive protein (CRP) and inflammatory cytokines in lung tissues of SpT4-infected mice, including nterleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). In conclusion, inhibition of miR-497-3p downregulates the expression of procalcitonin and ameliorates bacterial pneumonia in mice.

肺炎通常由多种病原体感染引起。导致肺炎的潜在机制仍然难以捉摸。在这里，研究了 microRNA-497-3p (miR-497-3p) 在细菌性肺炎中的作用。分别通过实时聚合酶链反应（RT-PCR）和酶联免疫吸附试验（ELISA）检测患者血清中miR-497-3p和降钙素原（PCT）的表达水平。在 A549 细胞系中进一步验证了 miR-497-3p 和 PCT 之间的相互作用。为进一步探索miR-497-3p在肺炎中的作用，通过Sp建立了细菌性肺炎小鼠模型。TIGR4 菌株 (SpT4) 感染。随后，将 LV-miR-497-3p 海绵施用于患有细菌性肺炎的小鼠。评估肺炎的严重程度和炎症反应。细菌性肺炎患者的血清 miR-497-3p 和 PCT 水平升高，并且 miR-497-3p 水平与 PCT 水平呈正相关。功能测定表明 CALCA 是 A549 细胞系中 miR-497-3p 的靶标。在患有细菌性肺炎的小鼠中，miR-497-3p 和 PCT 水平在 SpT4 感染后均上调。施用 LV-miR-497-3p 海绵可减轻肺炎，伴随着体重和血氧水平的增加，以及未受伤的肺。抑制 miR-497-3p 可减弱 SpT4 感染小鼠肺组织中 C 反应蛋白 (CRP) 和炎性细胞因子的表达，包括白介素-6（IL-6）和肿瘤坏死因子-α（TNF-α）。总之，抑制 miR-497-3p 可下调小鼠降钙素原的表达并改善细菌性肺炎。