Vitamin D Binding Protein: A Potential Factor in Geriatric COVID-19 Acute Lung Injury

Abstract

Hongjuan Jiang, Xiangyu Chi, Yanhong Sun, Hongwen Li Department of Geriatric Respiratory Disease, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, People’s Republic of ChinaCorrespondence: Hongwen Li, Department of Geriatric Respiratory Disease, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, People’s Republic of China, Email [email protected]: Previous research indicated that vitamin D binding protein (VDBP) is an independent multifunctional protein that plays a vital role in acute inflammatory and tissue damage. However, its role in acute lung injury (ALI) due to coronavirus disease 2019 (COVID-19) is unclear, and studies are lacking. This study intends to investigate the difference in serum VDBP levels in COVID-19 patients with ALI or without ALI and further explore the role of VDBP in the inflammatory response of ALI through cellular models.Methods: The serum was collected from COVID-19 patients, and the concentration of serum VDBP was detected. Construct a VDBP gene-silencing plasmid and transfect it into human alveolar epithelial A549 cells. After 72 hours of lipopolysaccharide (LPS) intervention, The inflammatory factors interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were detected, and cell counting kit-8 (CCK-8) assay was used to detect cell viability. Flow cytometry was used to detect cell apoptosis.Results: The serum concentration of VDBP was significantly higher in COVID-19 with ALI (P < 0.05). Correlation analysis indicated serum VDBP positively correlated with leukocyte (r=0.329, P = 0.002), c-reaction protein (r = 0.470, P < 0.001), serum amyloid A (r = 0.900, P < 0.001), procalcitonin (r = 0.670, P < 0.001), and interleukin 6 (r = 0.452, P < 0.001). Simultaneously, the logistic regression analysis showed that increased serum VDBP was an independent risk factor for ALI in COVID-19 patients (OR 1.003 95% CI 1.001– 1.006, P = 0.002). In human alveolar epithelial A549 cells, after LPS intervention, the inflammatory factor IL-1β and TNF-A significantly reduced in the VDBP gene silencing group compared to the negative control (NC) group (P < 0.05). The cell viability of the VDBP gene silencing group was significantly increased compared to the NC group, and the cell apoptosis rate was significantly reduced (P < 0.05).Conclusion: In COVID-19 patients, acute lung injury may lead to increased serum concentration of VDBP. VDBP plays a vital role in promoting inflammatory response and apoptosis of bronchial epithelial cells.Keywords: Vitamin D binding protein, COVID-19, acute lung injury, pathogenesis

Keywords

• vitamin d binding protein
• covid-19
• acute lung injury
• pathogenesis