Cysteine proteinase inhibitors in psoriatic epidermis

Abstract

Human psoriatic epidermis and scales were demonstrated to contain two antigenically separate cysteine proteinase inhibitors, one acidic with an isoelectric point of 4.7-5.0 (ACPI) and one neutral with an isoelectric point of 6.0-6.5 (NCPI), while normal epidermis contains only ACPI. The total papain (cysteine proteinase) inhibiting activity of the psoriatic epidermis as calculated per mg protein was higher than that in normal epidermis. Both ACPI and NCPI were localized immunocytochemically, mainly in the highest spinous cell layers with less activity in the parakeratotic cells and lower layers of spinous cells. Basal cells were essentially negative.

Properties and nature of a cysteine proteinase inhibitor located in keratohyalin granules of rat epidermis

“…Some cysteine proteinase inhibitors were isolated from human and rat skins, and characterized [2,3]. One of them, cystatin-cu, which belongs to family 1, has a low molecular weight and has been found in the skin in high levels, especially in the epidermal cells [4].…”

Topical Protease Therapy as a Novel Method of Epidermal Ablation: Preliminary Report

“…In addition to the ability to selectively ablate epidermal neoplasms, TPT may also prove useful in the treatment of several non‐neoplastic dermatologic conditions. Support for such applications comes from the previous identification of an endogenous 43 kD papain inhibitor from psoriatic scale 44,45 . This 43 kD papain inhibitor has subsequently been demonstrated in lesions of ichthyosis, eczema, actinic keratosis, verruca, condyloma, molluscum, Bowen's disease, and squamous cell carcinoma, as well as in fetal skin 46,47 .…”

“…Support for such applications comes from the previous identification of an endogenous 43 kD papain inhibitor from psoriatic scale. 44,45 This 43 kD papain inhibitor has subsequently been demonstrated in lesions of ichthyosis, eczema, actinic keratosis, verruca, condyloma, molluscum, Bowen's disease, and squamous cell carcinoma, as well as in fetal skin. 46,47 This is further underscored by a recent study that demonstrated defects in endogenous SCCE expression in squamoproliferative disorders such as actinic keratosis, ichthyosis vulgaris, and squamous cell carcinoma in situ.…”

Journey of cystatins from being mere thiol protease inhibitors to at heart of many pathological conditions

“…in several epimeroid carcinomas including squamous cell carcinomata of the lung, skin, vulva, cervix and oesophagus [41,42] but was absent from a variety of other carcinomas [43]. Additionally, the serum level of stefin A has been shown to increase significantly in patients with cardiovascular disease [44] and the inhibitor has been found in the upper spinous layer of psoriatic cells. Stefin A has been found to be a sensitive marker during HIV-1infection and for regeneration of follicular lymphoid tissue [45].…”