Galectin‐7 and actin are components of amyloid deposit of localized cutaneous amyloidosis

Abstract

The precursor protein of localized cutaneous amyloidosis (LCA) is believed to be cytokeratins on the basis of previous immunohistochemical studies. To identify the candidate amyloid protein biochemically, amyloid proteins were extracted with distilled water from lesional skin of LCA associated with Bowen's disease. The proteins were resolved on one- or two-dimensional polyacrylamide gel electrophoresis followed by characterization with immunoblot analysis. The proteins with multiple molecular weights of 50-67 kDa and two proteins with 25 and 35 kDa were identified as keratins, serum amyloid P component and apolipoprotein E, respectively. The unknown 14-kDa (pI = 7.0) and 42-kDa (pI = 5.4) proteins reacted with the antibody against galectin-7 and actin, respectively. The protein with the molecular weight of 14 kDa was identified as galectin-7 by MALDI-TOF mass spectrometer. Their electrophoretic mobilities were identical with normal counterparts extracted from cultured normal human keratinocytes. Galectin-7 and actin were detected by immunoblot assay in the water-soluble fractions prepared from the lesional skins of two patients with primary LCA. Immunohistochemical studies of tumor-associated (n = 9) and primary (n = 10) LCA revealed various degrees of positive immunoreactivities with the antibodies for galectin-7 and F-actin. Galectin-7 and actin, which contain considerable amount of β-sheet structure, may be candidate amyloidogenic proteins of primary and secondary LCA.

PUVA phototherapy-induced secondary amyloidosis in patients with mycosis fungoides: a rare adverse effect of phototherapy

“…Cytokeratin 5 is predominantly found in basal keratinocytes (25,26). In the pathogenesis of amyloidosis, a commonly accepted theory is that the apoptotic basal keratinocytes (colloid bodies) release cytokeratins, which are then covered with autoantibodies, phagocytized by macrophages, and enzymatically degraded to amyloid K (keratin-associated amyloid).…”

In Vitro Amyloidogenic Peptides of Galectin-7

“…Furthermore, the secondary structure of cytokeratin consisits of ␣-helical, coiled-coil rod domains (5), whereas more than 20 amyloidogenic proteins that can bind Congo red or ThT share common cross-␤ sheet structures, which is defined as ␤-fibrillosis (6). Recently, we identified galectin-7 (Gal-7), actin, and cytokeratins as well as serum amyloid P component (SAP) and apolipoprotein E (Apo E) as the major components of amyloid deposits of PLCA in the water soluble fraction recovered from lesional skin, and we found that all of these proteins were present in the amyloid deposits of PLCA according to immunohistochemical studies (2,(7)(8)(9). SAP and Apo E are universal nonfibrillar constituents of amyloid deposits and will therefore be excluded from the candidates for amyloid precursor protein.…”

“…Amyloid fibrils were sequentially extracted from the lesional skin of localized cutaneous amyloidosis with distilled water as described previously (7). The yield of the protein in the watersoluble fraction was ϳ90 g.…”

Odos Pokyčiai Sergant Amiloidoze

“…PLOA etiopatogenezė nėra žinoma, liga gali būti idiopatinė arba susijusi su genetine predispozicija [2,7]. Ši amiloidozės forma dažnai siejama su epidermio pažeidimu dėl lėtinės trinties (prurigo nodularis, lichen simplex chronicus, lėtinis niežėjimas) [2,4,8], Epštein-Baro viruso (EBV) infekcija [2], ultravioletiniais B spinduliais, rasine priklausomybe, atopija [5,7,9] ir trauma [10]. mo laikotarpiu, ja nežymiai dažniau serga moterys [4,5].…”

“…Dažniausi jų: bazoląstelinė ir plokščialąstelinė karcinoma, seborėjinė bei aktininė keratozė, intradermalinis melanocitinis ir linijinis karpinis epiderminis apgamas, prakaito liaukų navikai, pilomatriksoma, dermatofibroma, fotojautri žiedinė elastinė gigantinių ląstelių granulioma, Mibelli'o porokeratozė, trichoepitelioma, trichoblastoma, Bowen'o ligos ir odos T-ląstelių limfomos (mycosis fungoides) išraiškos odoje [1,2,4,8]. Panašus fenomenas gali būti stebimas po PUVA terapijos [1,4].…”