FasL and TRAIL Induce Epidermal Apoptosis and Skin Ulceration Upon Exposure to Leishmania major

Abstract

Receptor-mediated apoptosis is proposed as an important regulator of keratinocyte homeostasis in human epidermis. We have previously reported that Fas/FasL interactions in epidermis are altered during cutaneous leishmaniasis (CL) and that keratinocyte death through apoptosis may play a pathogenic role for skin ulceration. To further investigate the alterations of apoptosis during CL, a keratinocyte cell line (HaCaT) and primary human epidermal keratinocytes were incubated with supernatants from Leishmania major-infected peripheral blood mononuclear cells. An apoptosis-specific microarray was used to assess mRNA expression in HaCaT cells exposed to supernatants derived from L. major-infected cultures. Fas and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) mRNA and protein expression were significantly up-regulated, and apoptosis was detected in both HaCaT and human epidermal keratinocyte cells. The keratinocyte apoptosis was partly inhibited through blocking of Fas or FasL and even more efficiently through TRAIL neutralization. Up-regulation of Fas on keratinocytes in epidermis and the presence of FasL-expressing macrophages and T cells in dermis were previously reported by us. In this study, keratinocytes expressing TRAIL, as well as the proapoptotic receptor TRAIL-R2, were detected in skin biopsies from CL cases. We propose that activation of Fas and TRAIL apoptosis pathways, in the presence of inflammatory mediators at the site of infection, leads to tissue destruction and ulceration during CL. (Am J

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“…Human keratinocytes were tested in this study since they are the primary target for DOX-induced toxicities. HaCaT keratinocytes, although exhibited alterations in their life-span (immortalizion), were used as they express typical epidermal phenotype [25-27], of which making them common in vitro models to aid the mechanistic studies of skin and hair follicle [28,29]. …”

Oxidative Stress Mediates Chemical Hypoxia-Induced Injury and Inflammation by Activating NF-κb-COX-2 Pathway in HaCaT Cells

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Effectiveness of Apoptotic Factors Expressed on the Wounds of Patients With Stage III Pressure Ulcers

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