Shanghai Key Laboratory of Regulatory Biology, School of Life Sciences, East China Normal University, Shanghai, 200241, China.
Global Discovery Department, Mead Johnson Pediatric Nutrition Institute, Middenkampweg 2, 6545 CJ, Nijmegen, The Netherlands.
Inflamm Res. 2019 Aug;68(8):715-722. doi: 10.1007/s00011-019-01254-8. Epub 2019 Jun 5.
Nutritional factors such as extensively hydrolyzed casein (eHC) have been proposed to exert anti-inflammatory activity and affect clinical outcomes such as tolerance development in cow's milk allergy. Granzyme B (GrB) induces apoptosis in target cells and also controls the inflammatory response. Whether eHC could affect the activity of granzyme B and play a role in GrB-mediated inflammatory responses in vitro was unknown.
The activity of GrB was measured using the substrate Ac-IEPD-pNA. Inflammatory responses were induced with GrB in HCT-8 and THP-1 cells, and pro-inflammatory cytokines were determined at the transcriptional and protein level.
GrB could induce the expression of IL-1β in HCT-8 cells, and IL-8 and MCP-1 in THP-1 cells, respectively. Interestingly, GrB acted synergistically on LPS-induced inflammation in HCT-8 cells and eHC reduced pro-inflammatory responses in both GrB and LPS-mediated inflammation. Further analyses revealed that eHC could inhibit the biological activities and cytotoxic activities of GrB and then could reduce GrB-mediated inflammatory response.
The results from the current study suggest that anti-inflammatory activity of extensively hydrolyzed casein is, to a certain extent, mediated through modulation of granzyme B activity and responses.
水解酪蛋白（eHC）等营养因素被认为具有抗炎活性，并影响牛奶过敏患者的耐受发展等临床结局。颗粒酶 B（GrB）可诱导靶细胞凋亡，并控制炎症反应。eHC 是否会影响 GrB 的活性，以及是否会在体外影响 GrB 介导的炎症反应尚不清楚。
使用 Ac-IEPD-pNA 作为底物来测量 GrB 的活性。用 GrB 诱导 HCT-8 和 THP-1 细胞产生炎症反应，并在转录和蛋白水平上测定促炎细胞因子。
GrB 可分别诱导 HCT-8 细胞中 IL-1β和 THP-1 细胞中 IL-8 和 MCP-1 的表达。有趣的是，GrB 在 HCT-8 细胞的 LPS 诱导炎症中具有协同作用，eHC 可降低 GrB 和 LPS 介导的炎症中的促炎反应。进一步的分析表明，eHC 可以抑制 GrB 的生物学活性和细胞毒性活性，从而减少 GrB 介导的炎症反应。
本研究结果表明，水解酪蛋白的抗炎活性在一定程度上是通过调节颗粒酶 B 的活性和反应来介导的。
