Degradation of bovine achilles tendon collagen byCandida albicansproteinase

Abstract

Candida albicans, when cultivated in a medium containing insoluble bovine achilles tendon as a nitrogen source, was able to produce a collagen degrading proteinase. The degradation of achilles tendon collagen by the proteinase was verified by morphological change and the release of hydroxyproline. The proteinase activity was inhibited by pepstatin.Candida albicans, a dimorphic yeast, is an important opportunistic pathogen. It causes cutaneous or serious systemic candidiasis in a variety of clinical forms. However, the factors responsible for the pathogenicity of C. albicans have yet to be established. C. albicans proteinase has been proposed as one of the important virulence factors by Remold et al. [9], Chattaway et al. [1], MacDonald & Odds [6], Rfichel [10] and Odds [7]. Recently, Hattori et aL [4] described the relationship between proteolytic enzyme and candidiasis on the stratum corneum. Previously, we have reported on the dentinal collagen (type 1) degrading proteinase produced by C. albicans and we have suggested that this proteinase might be related to the progress of dentinal caries [3,5]. The present experiments provide evidence which shows that the C. albicans proteinase degrades native bovine achilles tendon collagen.The proteinase was prepared by the method described previously [5] except that dentinal collagen was replaced by bovine achilles tendon collagen. Briefly, C. albicans ATCC 1002 was cultured at 37°C in Yeast Carbon Base (Difco) containing 2% (w:v) achilles tendon collagen (type 1, insoluble, Sigma Chemical Co., St. Louis, Mo) as a nitrogen source. After 1 week of incubation, the culture supernatant was concentrated and the active proteinase fractions were separated by DEAE Sephacel columnchromatography at pH 6.7. The optimum pH for proteinase activity was 3.5-4.0. When collagen was used as a nitrogen source in culture media used to obtain the proteinase, it was added to the media after sterilization with ethylene oxide (1.0kgcm -2 at 50°C) for 6h.

Stimuli that induce production of Candida albicans extracellular aspartyl proteinase

“…In addition to bovine serum albumin (BSA) (Remold et al, 1968), proteinase production is induced in vitro by haemoglobin (Ruchel, 1981), histones and ovalbumin , keratin (Hattori et al, 1984), collagen (Kaminishi et al, 1986(Kaminishi et al, ,1988 and human serum (Capobianco et al, 1992). Complex mixtures of peptides (peptone and tryptone) can also stimulate proteinase production in vitro .…”

“…Correlation between virulence and levels of proteinase production in both clinical isolates of C. albicans (Ghannoum & Abu Elteen, 1986;De Bernardis et al, 1990) and laboratory isolates with altered proteinase levels (MacDonald & Odds, 1983;Kwon-Chung et al, 1985;Kondoh et al, 1987;Ross et al, 1990) generally supports the notion of its role in virulence. The proteinase hydrolyses a variety of extracellular substrates, including albumin (Remold et al, 1968), immunoglobulins, coagulation factor X, angiotensinogen analogues, and haemoglobin (Ruchel, 1986), keratin (Hattori et al, 1984) and collagen (Kaminishi et al, 1986(Kaminishi et al, , 1988.…”

Degradation of humoral host defense by Candida albicans proteinase

“…An extracellular proteinase from Candida albicans, reported by Staib (33), Remold et al (26), and Rüchel (28), has been characterized as a carboxyl proteinase (EC 3.4.23.6) has been considered an important virulence factor (2,22,25). The proteinase can break down a number of host substrates, including albumin (30), collagen (6,7), immunoglobulin A (IgA) (28), keratin (21), and hemoglobin (26). To explain the pathogenic role of the proteinase in Candida infection, studies including immunochemical study of pathological sections of patients (31) and experimental infection with proteinase-deficient Candida mutants (11,13) have been reported.…”

Specific inhibition of acid proteinase secretion inCandida albicansby Lys-Nva-FMDP

“…Secretion of proteinase was found to be correlated with other virulence properties of C. albicans cells, such as adherence [11]. In light of recent reports, the physiological role of this enzyme during colonization of the host organism by the fungus is thought to be: (i) degradation of skin and mucosal barriers which augments the adherence of fungal cells to host tissues [4,14,16]: (ii) digestion of host proteins in order to supply nutrients [20]; and (iii) breaking the immune barrier by attacking lymphocytes and macrophages [11,22]. Therefore, antimycotics able to inhibit either acid proteinase activity or its secretion should be considered as especially valuable potential anticandidal drugs.…”