Plant Cell Biotechnology Department, CSIR-Central Food Technological Research Institute (CFTRI), Mysuru, 570 020, India.
Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002, India.
In Vitro Cell Dev Biol Anim. 2022 May;58(5):419-428. doi: 10.1007/s11626-022-00691-w. Epub 2022 Jun 9.
Folate (vitamin B) and its biologically active derivatives are well-known antioxidant molecules protecting cells from oxidative degradation. The presence of high glucose, often found in diabetic patients, causes oxidative stress resulting in cellular stress and inflammatory injury. Cells in organs such as the lung are highly prone to inflammation, and various protective mechanisms exist to prevent the progressive disorders arising from inflammation. In the present study, the synthetic form of folate, i.e. folic acid, and active forms of folate, i.e. 5-methyltetrahydrofolate and 10-formyltetrahydrofolate, were evaluated for their antioxidant and antiinflammatory potential against high glucose (50 mM)-mediated oxidative stress and inflammation in BEAS-2B cells, an immortalised bronchial epithelial cell line. High glucose treatment showed a 67% reduction in the viability of BEAS-2B cells, which was restored to the viability levels seen in control cultures by the addition of active folate derivatives to the culture media. The DCFH-DA fluorometric assay was performed for oxidative stress detection. The high glucose-treated cells showed a significantly higher fluorescence intensity (1.81- and 3.8-fold for microplate assay and microscopic observation, respectively), which was normalised to control levels on supplementation with active folate derivatives. The proinflammatory NF-κB p50 protein expression in the active folate derivative-supplemented high glucose-treated cells was significantly lower compared to the folic acid treatment. In support of these findings, in silico microarray GENVESTIGATOR database analysis showed that in bronchiolar small airway epithelial cells exposed to inflammatory condition, folate utilization pathway genes are largely downregulated. However, the folate-binding protein gene, which encodes to the folate receptor 1 (FOLR1), is significantly upregulated, suggesting a high demand for folate by these cells in inflammatory situations. Supplementation of the active folate derivatives 5-methyltetrahydrofolate and 10-formyltetrahydrofolate resulted in significantly higher protection over the folic acid from high glucose-induced oxidative stress and inflammation. Therefore, the biologically active folate derivatives could be a suitable alternative over the folic acid for alleviating inflammatory injury-causing oxidative stress.
叶酸（维生素 B）及其生物活性衍生物是众所周知的抗氧化分子，可保护细胞免受氧化降解。高血糖（常在糖尿病患者中发现）会导致氧化应激，从而导致细胞应激和炎症损伤。肺等器官的细胞极易发生炎症，存在各种保护机制以防止炎症引起的进行性疾病。在本研究中，评估了叶酸的合成形式，即叶酸，以及叶酸的活性形式，即 5-甲基四氢叶酸和 10-甲酰基四氢叶酸，以评估其对 BEAS-2B 细胞（一种永生化的支气管上皮细胞系）中高葡萄糖（50mM）介导的氧化应激和炎症的抗氧化和抗炎潜力。高葡萄糖处理使 BEAS-2B 细胞的活力降低了 67％，通过向培养基中添加活性叶酸衍生物，将其活力恢复到对照培养物的水平。通过 DCFH-DA 荧光测定法检测氧化应激。高葡萄糖处理的细胞显示出明显更高的荧光强度（微孔板测定法和显微镜观察分别为 1.81 和 3.8 倍），在补充活性叶酸衍生物后，该荧光强度恢复到对照水平。在补充活性叶酸衍生物的高葡萄糖处理的细胞中，促炎性 NF-κB p50 蛋白表达明显低于叶酸处理。支持这些发现的是，在基于微阵列的 GENVESTIGATOR 数据库分析中，暴露于炎症条件下的细支气管小气道上皮细胞中，叶酸利用途径基因被大大下调。但是，叶酸结合蛋白基因（编码叶酸受体 1（FOLR1））显著上调，表明这些细胞在炎症情况下对叶酸的需求量很高。补充活性叶酸衍生物 5-甲基四氢叶酸和 10-甲酰基四氢叶酸可显著优于叶酸，防止高葡萄糖引起的氧化应激和炎症。因此，与叶酸相比，生物活性叶酸衍生物可能是缓解引起炎症损伤的氧化应激的合适替代品。
