Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA.
J Thromb Haemost. 2021 Jan;19(1):269-280. doi: 10.1111/jth.15133. Epub 2020 Dec 7.
Essentials Activated protein C (APC) is a serine protease with anticoagulant and cytoprotective effects. We tested whether APC or non-canonical PAR-derived peptides suppress inflammasome activity. APC or PAR1- and PAR3-derived peptides restrict inflammasome-dependent caspase-1 activity. Combined PAR1-derived and PAR3-derived peptides synergistically suppress caspase-1 activity. ABSTRACT: Background Activated protein C (APC) has been shown to restrict murine inflammasome activity. However, whether APC can exert anti-inflammatory activity in part through suppression of inflammasome activation in human systems is unknown. Objectives Studies were made to determine whether either APC or protease activated receptor (PAR)-derived peptides can reduce NLRP3 inflammasome activity in differentiated human THP-1 macrophage-like cells or in primary human monocytes stimulated to activate the inflammasome. Methods Human THP-1 cells or primary human monocytes were differentiated, treated with APC or PAR-derived peptides, and then stimulated with lipopolysaccharide and ATP to induce caspase-1 activity, a product of inflammasome activation. Results Activated protein C or noncanonical PAR1-derived or PAR3-derived peptides significantly reduced caspase-1 activity, detection of fluorescent NLRP3, and IL-1β release from THP-1 cells. At low concentrations where no effect was observed for each individual peptide, combinations of the PAR1-derived peptide and the PAR3-derived peptide resulted in a significant synergistic decrease in caspase-1 and IL-1β release. Caspase-1 activity was also reduced in primary human monocytes. Studies using blocking antibodies and small molecule PAR1 inhibitors suggest that EPCR, PAR1, and PAR3 each play roles in the observed anti-inflammatory effects. Several shortened versions of the PAR1- and PAR3-derived peptide reduced caspase-1 activity and exhibited synergistic anti-inflammatory effects. Conclusions The results indicate that both APC and certain PAR1- and PAR3-derived peptides, which are biased agonists for PAR1 or PAR3, can reduce inflammasome activity in stimulated human monocytes as measured by caspase-1 activity and IL-1β release and that PAR-derived biased peptide agonist combinations are synergistically anti-inflammatory.
活化蛋白 C（APC）是一种具有抗凝和细胞保护作用的丝氨酸蛋白酶。我们测试了 APC 或非经典 PAR 衍生肽是否能抑制炎症小体的活性。APC 或 PAR1 和 PAR3 衍生肽限制炎症小体依赖性半胱天冬酶-1 的活性。PAR1 衍生和 PAR3 衍生的肽联合协同抑制半胱天冬酶-1 的活性。摘要：背景 活化蛋白 C（APC）已被证明可限制小鼠炎症小体的活性。然而，APC 是否可以通过抑制人系统中炎症小体的激活来发挥抗炎活性尚不清楚。目的 研究 APC 或蛋白酶激活受体（PAR）衍生肽是否可以降低分化的人 THP-1 巨噬样细胞或刺激激活炎症小体的原代人单核细胞中的 NLRP3 炎症小体活性。方法 分化人 THP-1 细胞或原代人单核细胞，用 APC 或 PAR 衍生肽处理，然后用脂多糖和 ATP 刺激诱导半胱天冬酶-1 活性，即炎症小体激活的产物。结果 APC 或非经典 PAR1 衍生或 PAR3 衍生肽显著降低了 caspase-1 活性、THP-1 细胞中荧光 NLRP3 的检测和白细胞介素-1β的释放。在每种单独肽没有观察到作用的低浓度下，PAR1 衍生肽和 PAR3 衍生肽的组合导致 caspase-1 和白细胞介素-1β释放的显著协同减少。在原代人单核细胞中也降低了半胱天冬酶-1 的活性。使用阻断抗体和小分子 PAR1 抑制剂的研究表明，EPCR、PAR1 和 PAR3 都在观察到的抗炎作用中发挥作用。几种缩短的 PAR1 和 PAR3 衍生肽降低了半胱天冬酶-1 的活性，并表现出协同的抗炎作用。结论 结果表明，APC 和某些 PAR1 和 PAR3 衍生肽（PAR1 或 PAR3 的偏倚激动剂）都可以降低刺激的人单核细胞中的炎症小体活性，如通过半胱天冬酶-1 活性和白细胞介素-1β释放来测量，并且 PAR 衍生的偏倚肽激动剂组合具有协同的抗炎作用。
