An investigation into the mechanism of collagenolytic activity in colonic mucosa by a tissue culture method.

The process of collagenolysis and the source of collagenase liberated from different cell types in the colonic mucosa has been investigated by the lysis of collagen gels in vitro. The reconstituted collagen gel strongly reacted to periodic acid Schiff (PAS) when stained with combined alcian blue-PAS, indicating the presence of glycoprotein with neutral sugars in the collagen gel. Colonic explants of rabbits produced visible collagenolysis. An area of alcian blue stained gel was seen replacing the usual PAS staining around the area of the lysis. Several histochemical methods revealed that the columnar cells had multiplied with high enzymatic activity and penetrated the collagen gel where collagenolysis took place. The action of several proteolytic enzymes on collagen gel showed that ficin caused lytic activity, even though collagen is resistant to most proteolytic enzymes. Papain, pepsin and trypsin altered composition of collagen gel from neutral mucopolysaccharide to acid mucopolysaccharide. Collagenase and pronase at low concentration were found to cause extensive collagenolysis. The synthesis and breakdown of collagen is a desirable balanced process in the remodelling of connective tissue. This dynamic equilibrium may be achieved through the subtle interplay of cells liberating and inhibiting collagenase.     

Kinetics of collagenase and neutral protease release by neutrophils exposed to microcrystalline sodium urate

The rates of release of the various enzymes from PMN leukocytes exposed to MSU crystals were measured. Lysozyme and neutral protease appeared to be released simultaneously and release appeared to be essentially complete by 60 minutes. In contrast, collagenase was detected only after 30 minutes incubation, reached peak concentration at 90 minutes and dropped noticeably by 180 minutes. The presence of these enzymes was not due to cell lysis since only 10% of the total cellular LDH was present in the supernates. The levels of total and active collagenase in the supernatants were measured. In contrast to latent collagenase, active collagenase levels increased continually throughout the incubation period. The gradual increase in level of active collagenase may explain the corresponding drop of latent collagenase in the longer incubation (90 minutes or more) as the latter apparently is converted to active form. The effects of collagenase on Type I collagen were examined by SDS gel electrophoresis.     

Simple procedure for assessing relative quantities of neutral and acidic sugars in mucin glycoproteins: its use in assessing cyclical changes in cervical mucins.

A simple histochemical procedure for assessing relative amounts of neutral and acidic sugars in mucin glycoproteins, and its application in the study of cyclical changes of human cervical mucins, is described. This procedure, the saponification/selective periodate oxidation/borohydride reduction/alcian blue pH 2.5/periodic acid Schiff (KOH/PA*/Bh/Ab 2.5/PAS) method, uses a selective oxidation step to remove the PAS positivity of sialic acid; thus only neutral sugars stain positively with PAS, and acidic sugars (O-sulphate esters and carboxyl groups) stain with alcian blue. This differs from the KOH/Ab/PAS technique which stains sialic acid residues with both alcian blue and PAS. Applying the KOH/PA*/Bh/Ab 2.5/PAS technique to the study of cyclical changes of human cervical mucins, a decreased neutral:acidic sugar ratio in the secretory phase mucins compared with those of the proliferative phase was found. This difference was not seen with KOH/Ab/PAS staining in the same cases. The techniques and reagents used in this procedure can be easily applied in a clinical histopathology laboratory.     

Identification of proteases from periodontopathogenic bacteria as activators of latent human neutrophil and fibroblast-type interstitial collagenases.

Activation of latent human fibroblast-type and neutrophil interstitial procollagenases as well as degradation of native type I collagen by supra- and subgingival dental plaque extracts, an 80-kDa trypsinlike protease from Porphyromas gingivalis (ATCC 33277), a 95-kDa chymotrypsinlike protease from Treponema denticola (ATCC 29522), and selected bacterial species commonly isolated in periodontitis was studied. The bacteria included were Prevotella intermedia (ATCC 25261), Prevotella buccae (ES 57), Prevotella oris (ATCC 33573), Porphyromonas endodontalis (ES 54b), Actinobacillus actinomycetemcomitans (ATCC 295222), Fusobacterium nucleatum (ATCC 10953), Mitsuokella dentalis (DSM 3688), and Streptococcus mitis (ATCC 15909). None of the bacteria activated latent procollagenases; however, both sub- and supragingival dental plaque extracts (neutral salt extraction) and proteases isolated from cell extracts from potentially periodontopathogenic bacteria P. gingivalis and T. denticola were found to activate latent human fibroblast-type and neutrophil interstitial procollagenases. The fibroblast-type interstitial collagenase was more efficiently activated by bacterial proteases than the neutrophil counterpart, which instead preferred nonproteolytic activation by the oxidative agent hypochlorous acid. The proteases were not able to convert collagenase tissue inhibitor of metalloproteinase (TIMP-1) complexes into active form or to change the ability of TIMP-1 to inhibit interstitial collagenase. None of the studied bacteria, proteases from P. gingivalis and T. denticola, or extracts of supra- and subgingival dental plaque showed any significant collagenolytic activity. However, the proteases degraded native and denatured collagen fragments after cleavage by interstitial collagenase and gelatinase. Our results indicate that proteases from periodontopathogenic bacteria can act as direct proteolytic activators of human procollagenases and degrade collagen fragments. Thus, in concert with host enzymes the bacterial proteases may participate in periodontal tissue destruction.     

Collagenase activity of cartilage in rats with experimental lathyrism: a model of bone diseases

Collagenolytic activity was estimated in skin and joint cartilage of lathyritic rats by means of a biological assay. Lathyrism was induced by feeding beta-aminopropionitrile fumarate for six weeks, and the lathyritic state was confirmed by characteristic radiographic, histomorphologic and biochemical findings. Both tissues in lathyritic animals revealed significantly increased collagenolytic activity in comparison with those of the control animals. Studies were performed using ethylendiaminetetraactate and normal rat serum to determine the origin of inhibition of the collagenolytic system inhibition. Since both agents showed no inhibition of collagenolysis, the highly increased collagenolytic activity in lathyritic skin and joint cartilage appears not to be derived from polymorphonuclear cells nor from serum, but from the tissue itself. Elevation of collagenase activity may be important with respect to the increased neutral salt solubility of collagen and hydroxyproline excretion observed in experimental lathyrism.     

Simple method for collagenase determination in 38 Pseudomonas aeruginosa strains.

Collagenase enzyme activity of 38 Pseudomonas aeruginosa strains and 38 strains of Escherichia coli from various pathological sources was measured by a simple method. This method uses plates with collagen gel. The rate of gel lysis is proportional to the collagenase concentration. The method is simple and requires no special materials or equipment. From the 38 P. aeruginosa strains, 34 were collagenase positive. All 38 strains of E. coli were collagenase negative.     

Collagenase in the lower respiratory tract of patients with idiopathic pulmonary fibrosis.

To test the hypothesis that idiopathic pulmonary fibrosis (IPF) is mediated through collagenase present in the lower respiratory tract, we used the fiberoptic bronchoscope to obtain fluid from the lower respiratory tract of 24 patients with IPF, 18 controls and nine patients with sarcoidosis. The fluid was analyzed for a variety of enzymes, including collagenase. Fifteen of 21 patients with IPF showed collagenase activity, whereas normal controls and patients with sarcoidosis showed none (P greater than 0.001, for all comparisons). In two patients with IPF who were re-evaluated after eight to 24 months, the collagenase activity was persistent. Fluid from patients with IPF also contained elevated levels of a non-specific neutral protease (P greater than 0.01 compared with controls), but there was no elastase activity in fluid from patients with IPF or from controls. The collagenase found in lavage fluid in IPF cleaved lung collagen into collagenase-specific TCA and TCB fragments. We conclude that in IPF the collagen of the lung is subjected to sustained lysis, followed by disordered resynthesis, and that the presence of active collagenase in the lower respiratory tract is a specific feature of the alveolitis associated with this disease.     

Collagenolytic activity by malignant tumours

Five carcinomas and 5 sarcomas were investigated in relation to their production of neutral proteases capable of digesting polymeric collagen. The carcinomas were far more active than the sarcomas but all the malignant tumours produced enzymes which were capable of causing collagenolysis in vitro. collagenolytic enzymes were recovered from extracts of neoplastic cells from long-term culture, from the media in which these cells were cultured, from the media of mixed cell cultures (neoplastic, stromal and inflammatory cells from minced tumours), and from normal fibroblasts cultures. In contrast to the cultures of non-neoplastic fibroblasts, the tumour cells produced active enzymes, since limited proteolysis with trypsin or treatment with p-aminophenyl-mercuric acetate (APMA) caused no increase in enzyme activity. These tumours possess collagenolytic ability in vitro which may be partly responsible for their invasive nature in vivo.     

人腹膜假黏液瘤原代细胞培养及鉴定

目的体外培养和扩增腹膜假黏液瘤(PMP)原代细胞,为腹膜假黏液瘤的研究及药物筛选提供基础。方法用胶原酶消化法分离5例腹膜假黏液瘤样本并进行原代细胞培养,然后用染色体核型分析鉴定培养的细胞是否为肿瘤细胞;再用PAS染色检测细胞中性黏多糖;3D细胞培养模拟肿瘤在体内的状态;HE染色观察3D细胞的组织形态;裸鼠成瘤实验检测原代细胞的致瘤性。结果 PMP细胞原代培养5例均成功;2D培养的细胞贴壁增殖,形态为多边形鹅卵石样排列,可传代到18代;染色体核型分析显示大多数细胞是亚二倍体核型的肿瘤细胞;细胞PAS染色阳性,说明培养的原代细胞内含有黏液;3D培养的类器官与体内肿瘤组织形态相似;裸鼠成瘤率低,且形成的肿瘤与患者PMP相似度不高。结论 PMP原代细胞可在体外培养和扩增。     

Host-mediated effectors of tumor invasion: role of mast cells in matrix degradation

The role of collagenolytic enzymes in tumor invasion and metastasis has been emphasized, but the source of enzyme activity has remained unclear. Degradation of stromal connective tissue is a common feature of invasive neoplasia, and host-tumor cell interactions are probably important for localized collagenolysis. We have examined the role of mast cells in malignant cell invasion using cells derived from the rat mammary adenocarcinoma 13762NF. Histologic studies have shown increased numbers of mast cells at the zone of tumor invasion. Mast cell products and conditioned medium from such cells stimulated the production of collagenolytic enzymes by stromal fibroblasts as well as certain subpopulations of tumor cells in vitro. The tumor cell response to mast cell-mediated stimulation of collagenolysis appears to be related to the metastatic potential of the tumor cell. A subpopulation of host fibroblasts derived from the invading tumor zone was also found to be more responsive to mast cell factors than normal fibroblasts, as judged by collagenase production. Thus the mast cell has the potential to induce collagenolytic activity from both host fibroblasts and tumor cells.     

灰鹤(Grus grus)消化系统各器官蛋白水解酶的种类和活性研究

目的 研究灰鹤(Grus grus)消化系统各器官蛋白水解酶的种类和性质,为探讨野生鸟类的分类地位、系统演化提供基础资料.方法 采用蛋白水解酶复性电泳(G-PAGE)技术.结果 1.灰鹤消化系统蛋白水解酶种类多,在各种pH条件下,共计有26种;2.灰鹤消化系统蛋白水解酶的活性受pH值的影响和制约,在中性条件下酶活性最强,酸性条件下最弱,总的酶活性表现为中性＞碱性＞酸性;3.同一器官在不同的pH条件下,蛋白水解酶的种类和活性有较大的变化,不同器官蛋白水解酶的最适pH条件各不相同;4.在各种pH条件下,19 kD酶带普遍存在于除腺胃以外的各器官中,在中性条件下,各消化器官都分布有66和22 kD两条酶带.结论 灰鹤消化系统蛋白水解酶的最适pH为7.0;66、22、19 kD酶带的分布、活性及pH依赖性特点是灰鹤消化系统蛋白水解酶的主要特征.     

Synthesis and supramolecular organization of components of the extracellular matrix by fibroblasts cultured in a collagen lattice]

Fibroblasts cultured in a collagen gel contract and organize the gel into a three-dimensional matrix of collagen fibers. Within this matrix, the fibroblast cell cycle is blocked at the G1 phase but also at the G2 phase. The fibroblasts produce the main extracellular matrix components (collagen, noncollagen proteins, glycosaminoglycans), although in small amounts. Studies using this in vitro model with radiolabeled precursor substances (14C proline, 3H glucosamine) demonstrated production of supermolecular complexes which resisted to proteolysis by pepsin and collagenase and could not be isolated by saline precipitation. Polyclonal antibodies identified type I collagen, type VI collagen and fibronectin in this coherent supermolecular structure. The presence of glycosaminoglycans was also demonstrated by alcian blue precipitation.     

Collagen-bound collagenase

The presence of collagenase bound to collagen extracted and purified from several animal and human sources by a standard procedure has been confirmed by different methods. Polyacrylamide (10%) gel electrophoresis at pH 8.1 of intact or "spontaneously"degraded neutral salt soluble collagen results in the separation of two components: the upper one says at the origin and represents collagen or collagen ragments, whereas the lower protein component contains no collagen, often preserves specific collagenolytic activity, and migrates as a single band in SDS/polyacrylamide electrophoresis. With lower polyacrylamide gel concentration the electrophoretic separation of the two components is less clear. Removal of the lower protein component from collagen solutions by two different methods (TCA-ethanol purification cycles and pepsin digestion) results in concomitant loss of their "spontaneous" instability. Eluates of the lower protein component stimulate the heterologous production of a monospecific antibody capable of inhibiting the collagenolytic activity of homologous crude collagenase preparations. It is suggested that collagen-bound collagenase is not an artifact of the extraction procedure but rather a physiological reality, probably corresponding in the living animal to the enzyme closely associated with extracellular collagen fibers, revealed by immunohistochemical methods.     

Unexpected Results of Trichrome Staining of Quenched Epithelial Tissue Following Delayed Fixation

Abstract

The histological effects of freezing and thawing unfixed tissue before experimental diffusion studies across the mucosal barrier were investigated in the face of claims that such treatment was of little significance. Following fixation, tissue sections were stained by periodic acid-Schiff (PAS), alcian blue (pH 1.0 & 2.5)-PAS, Masson and Mallory trichromes, acid-picro-Mallory phosphotungstic acid-hematoxylin, Martius-scarlet-blue, luxol-fast-blue, and Sudan black B. Trichrome type staining revealed a previously unrecorded artifact, particularly evident in quenched tissues. Three distinct epithelial cell types could be identified on the basis of differential dye uptake. This finding was not evident in PAS, alcian blue, or Sudan black B stained sections. We postulate that distortion of the cellular matrix occurs as a result of the freeze, thaw, diffusion, and fix sequence and that these cells illustrate the well known phenomenon of tissue density/dye molecular size differential staining by acid dyes. (The J Histotechnol 16:343, 1993)     

Histochemical studies on mucin-rich cells in the digestive tract of a teleost, the Buenos Aires tetra (Hyphessobrycon anisitsi)

Types of mucus cells and mucins in the epithelial cell layer throughout the digestive tract of the Buenos Aires tetra (Hyphessobrycon anisitsi) are described and compared. The mucin was produced in three different cell types: in sac-like cells in the esophagus, in surface epithelial cells in the stomach and in goblet cells in the caeca and intestine. Nearly the entire esophageal epithelial cell layer consisted of mucus cells, filled by both neutral mucin and non-sulfated acidic mucin. The gastric mucin occurred in the distal area of the surface epithelial cells only and contained mainly neutral proteoglycans rich in glucosamine and some galactosamine and sialic acid. The goblet cells contained mainly non-sulfated acidic mucin in the caeca and sulfated acidic mucin throughout the entire intestine. Much glucosamine and some galactosamine and sialic acid occurred regularly in these cells in both the caeca and intestine. The observation that goblet cells often displayed colors ranging between blue and purple-magenta when alcian blue staining was followed by periodic acid-Schiff (PAS), or between blue and red-brown when the alcian blue was followed by neutral red, may reflect different ages or stages of development and differentiation for these cells. The highly variable affinities to wheat germ agglutinin (WGA-lectin) seen in these cells in the present study strengthens this view. However, such results may also suggest a true cellular heterogeneity reflecting various roles in lubrication, immunological defence, digestion and absorption.     

Comparative evaluation of the depth of collagen and hyaluronic acid hydrolysis <Emphasis Type="Italic">in vitro</Emphasis> by collagenase and hyaluronidase preparations

The molecular weights of collagen and hyaluronic acid solutions after their incubation with collagenase and hyaluronidase were evaluated by capillary viscosimetry. The results indicate high amylolytic activity of collagenase and the absence of proteolytic activity in hyaluronidase in an in vitro system. Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 146, No. 7, pp. 89–90, July, 2008     

Elucidating the Function of Non catalytic Domains of Collagenases and Aggrecanases

Metalloproteinases that degrade extracellular matrix molecules play important roles in development and progression of various diseases. Among them, collagenases are unique as they have an ability to degrade triple helical interstitial collagens into 3/4 and 1/4 fragments, a crucial step for collagenolysis in the tissue. Collagenases, consisting of a catalytic domain and a hemopexin domain, requires both domains for collagenolysis. The enzymes unwind triple helical collagen before they hydrolyze the peptide bonds. Aggrecanases are also multidomain metalloproteinases belonging to the ADAMTS family, and the noncatalytic ancillary domains also play an important role in recognition of aggrecan and their activities. Attenuation of collagenase and aggrecanase activities will be achieved by inhibitors or antibodies that interact directly with those noncatalytic ancillary domains (exosite inhibitors). Such molecules will be attractive for therapy as they will be highly selective because they are based on the unique mechanism of each proteinase.     

Elucidating the function of non catalytic domains of collagenases and aggrecanases

Metalloproteinases that degrade extracellular matrix molecules play important roles in development and progression of various diseases. Among them, collagenases are unique as they have an ability to degrade triple helical interstitial collagens into 3/4 and 1/4 fragments, a crucial step for collagenolysis in the tissue. Collagenases, consisting of a catalytic domain and a hemopexin domain, requires both domains for collagenolysis. The enzymes unwind triple helical collagen before they hydrolyze the peptide bonds. Aggrecanases are also multidomain metalloproteinases belonging to the ADAMTS family, and the noncatalytic ancillary domains also play an important role in recognition of aggrecan and their activities. Attenuation of collagenase and aggrecanase activities will be achieved by inhibitors or antibodies that interact directly with those noncatalytic ancillary domains (exosite inhibitors). Such molecules will be attractive for therapy as they will be highly selective because they are based on the unique mechanism of each proteinase.     

In vitro transformation of chondroprogenitor cells into osteoblasts and the formation of new membrane bone

Mandibular condyles of fetal mice 19 to 20 days in utero were kept in an organ culture system for up to 10 days. After 2 days in culture the cartilage of the mandibular condyle appeared to have maintained all its inherent structural characteristics, including its various cell layers: chondroprogenent structural characteristics, including its various cell layers: chondroprogenitor, chondroblastic, and hypertrophic. After 5 days in culture no chondroblasts could be seen and, instead, the entire cartilage was occupied by hypertrophic chondrocytes. At the same time, the mesenchymal cells at the chondroprogenitor zone differentiated into osteoblasts which produced osteoid. Light microscopic examinations showed that the newly formed osteoid did not stain with acidic toluidine blue or with alcian blue, but stained intensively with the van Gieson stain and with Periodic acid-Schiff (PAS). The osteoid reacted with antibodies against type I collagen but not with antibodies against type II collagen. Electron microscopic examinations showed that the mineralization appeared to be associated with collagen fibers in bone rather than with matrix vesicles in the cartilage. The process of bone formation progressed with time and by the 10th day new bone replaced almost the entire cartilage, thus forming an expanded layer of membrane bone. This in vitro system represents an experimental model whereby undifferentiated precursor cells transform into osteoblasts with the subsequent formation of a typical membrane bone.     

耻骨联合可作为组织工程种子细胞的供区?

背景：耻骨联合是与关节盘、半月板或椎间盘具有相同性质的组织,但是将其作为组织工程种子细胞供区的研究,至今鲜有报道。 目的：观察耻骨联合作为组织工程种子细胞供区的可行性。 方法：取大鼠的耻骨联合组织进行苏木精-伊红、阿尔新蓝及Ⅱ型胶原免疫组织化学染色,观察细胞外基质的组织学特征。再将分离自大鼠耻骨联合组织的细胞,在体外培养扩增后,与藻酸盐凝胶支架复合立体培养,通过活细胞荧光标记方法,观察细胞存活率,通过21 d长期培养观察细胞增殖情况。测量8具成年男性骨盆标本的耻骨联合软骨区的体积,判断其是否有利于分离足够数量的种子细胞。 结果与结论：苏木精-伊红染色显示,大鼠耻骨联合组织有大量平行或交叉排列的纤维束,细胞单独散在、成对或成行排列分布于纤维束之间的陷窝内。阿尔新蓝染色和Ⅱ型胶原免疫组织化学染色发现,大鼠耻骨联合组织广泛着色,细胞及陷窝附近着色较深。藻酸盐凝胶支架为多孔结构,孔隙间交互通连,孔隙直径为(27.0±16.7) μm,孔隙壁较光滑。在支架上细胞存活率为(72.4±4.5)%。在体外长期培养过程中,支架上的细胞呈圆球形,逐渐形成“同源细胞群”,培养13 d时观察到的细胞团,在第21天时明显增大,所含细胞数明显增多。成年男性耻骨联合组织的体积为(1.13±0.21) cm³。结果证实,大鼠耻骨联合组织细胞具有软骨细胞的排列特征,细胞外间质有软骨组织特异性基质成分。取自大鼠耻骨联合的细胞,在体外立体培养具有持续的增殖能力,耻骨联合组织可作为软骨组织工程种子细胞供区。成年男性耻骨联合组织量较大,有利于分离获取较多的原代细胞。