Filaggrin-dependent secretion of sphingomyelinase protects against staphylococcal α-toxin-induced keratinocyte death
Filaggrin-dependent secretion of sphingomyelinase protects against staphylococcal α-toxin-induced keratinocyte death
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DOI：
10.1016/j.jaci.2012.10.030
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发表时间：
2013-02-01
影响因子：
14.2
通讯作者：
Leung, Donald Y. M.
中科院分区：
文献类型：
--
作者：
Brauweiler, Anne M.;Bin, Lianghua;Leung, Donald Y. M.
背景资料：特应性皮炎（AD）患者的皮肤在角质形成细胞分化方面存在缺陷，特别是在表皮屏障蛋白聚丝蛋白的表达方面。AD皮肤病变通常因金黄色葡萄球菌介导的毒力因子α毒素分泌而加重。目前尚不清楚缺乏角质形成细胞分化是否会导致葡萄球菌毒素的致死率增加。目的：我们研究了角质形成细胞分化和丝聚蛋白表达是否能防止staphylococcal α-toxin.Methods诱导的细胞死亡：通过小干扰RNA基因敲低产生丝聚蛋白缺陷的原代角质形成细胞。通过使用实时PCR测定RNA表达。通过使用乳酸脱氢酶测定来确定细胞死亡。基于角蛋白5染色确定丝聚蛋白缺陷（ft/ft）小鼠皮肤活检中的角化细胞存活。α-毒素七聚体的形成和酸性鞘磷脂酶的表达，通过免疫印迹法测定。结果：我们发现，聚丝蛋白的表达，角化细胞分化的结果发生，显着抑制葡萄球菌α-毒素介导的致病性。此外，丝聚蛋白通过介导鞘磷脂酶的分泌在保护细胞中起关键作用，鞘磷脂酶是一种减少角质形成细胞表面上α-毒素结合位点数量的酶。最后，我们确定，鞘磷脂酶的酶活性直接防止α-毒素结合和保护角质形成细胞免受α-毒素诱导的cytotoxic.Conclusions：目前的研究介绍了新的概念，金黄色葡萄球菌α-毒素优先目标和破坏丝聚蛋白缺乏角质形成细胞。它还提供了一种机制，以解释增加的倾向，金黄色葡萄球菌介导的恶化的AD皮肤病。（J Allergy Clin Immunol 2013;131：421-7.）
Background: The skin of patients with atopic dermatitis (AD) has defects in keratinocyte differentiation, particularly in expression of the epidermal barrier protein filaggrin. AD skin lesions are often exacerbated by Staphylococcus aureus-mediated secretion of the virulence factor alpha-toxin. It is unknown whether lack of keratinocyte differentiation predisposes to enhanced lethality from staphylococcal toxins. Objective: We investigated whether keratinocyte differentiation and filaggrin expression protect against cell death induced by staphylococcal alpha-toxin.Methods: Filaggrin-deficient primary keratinocytes were generated through small interfering RNA gene knockdown. RNA expression was determined by using real-timePCR. Cell death was determined by using the lactate dehydrogenase assay. Keratinocyte cell survival in filaggrin-deficient (ft/ft) mouse skin biopsies was determined based on Keratin 5 staining. alpha-Toxin heptamer formation and acid sphingomyelinase expression were determined by means of immunoblotting.Results: We found that filaggrin expression, occurring as the result of keratinocyte differentiation, significantly inhibits staphylococcal alpha-toxin-mediated pathogenicity. Furthermore, filaggrin plays a crucial role in protecting cells by mediating the secretion of sphingomyelinase, an enzyme that reduces the number of alpha-toxin binding sites on the keratinocyte surface. Finally, we determined that sphingomyelinase enzymatic activity directly prevents alpha-toxin binding and protects keratinocytes against alpha-toxin-induced cytotoxicity.Conclusions: The current study introduces the novel concept that S aureus alpha-toxin preferentially targets and destroys filaggrin-deficient keratinocytes. It also provides a mechanism to explain the increased propensity for S aureus-mediated exacerbation of AD skin disease. (J Allergy Clin Immunol 2013;131:421-7.)