Purification of an active gelatinase from collagen fiber fraction of granulation tissue in rats

A cysteine-activated protease isolated from Todarodes pacificus squid degrades collagen below its denaturation temperature

Collagen purified from the mantle muscle of the Japanese common squid, Todarodes pacificus, showed autodegradation during incubation under acidic conditions at 25 degrees C, without the addition of exogenous enzymes. This suggests that the collagenolytic proteases bind to collagen tightly through the steps of collagen preparation. Collagenolytic activity also was detected in a crude extract of mantle muscle, and leupeptin and E-64 were observed to inhibit collagenolytic activity within the collagen fraction and muscle extract. We purified these collagenolytic cysteine proteases by leupeptin column chromatography and cellulose acetate membrane electrophoresis. Optimal enzymatic activity was observed at pH 3.5, and collagenolytic activity was completely suppressed at neutral or alkaline pH. The purified enzymes were 28 kDa and 25 kDa in size, and both had gelatinolytic activity, as detected by gelatin zymography, and cut the specific site of denatured collagen alpha chain. The purified enzymes degraded squid collagen at 25 degrees C, which is 2.5 degrees lower than the temperature at which squid collagen normally denatures; however, the proteases were ineffective at 20 degrees C. Interestingly, the isolated proteases were capable of digesting both squid and bovine gelatin. In this article, we describe collagenolytic cysteine proteases that bind to the collagen of Todarodes pacificus, thereby digesting it by attacking microunfolding regions generated by incubation 2-3 degrees C below the denaturation temperature.

A 16-kDa fragment of collagen type XIV is a novel neutrophil chemotactic factor purified from rat granulation tissue

A neutrophil chemotactic factor has been purified from the homogenate of rat granulation tissues. The purified chemoattractant was a basic protein with heparin-binding site and gave a single band corresponding to a molecular mass of 16 kDa on SDS-PAGE under reducing conditions. The chemoattractant was treated with lysylendopeptidase and the resulting peptides were isolated by reversed-phase HPLC. Amino acid sequences of the peptides were almost identical with the sequence of N-terminal fibronectin type III domain of human collagen type XIV, suggesting that the purified chemoattractant consists mainly of N-terminal fibronectin type III domain and the adjacent heparin-binding site of rat collagen type XIV. The 16-kDa fragment of collagen type XIV dose dependently attracted rat neutrophils and transiently increased the intracellular free Ca2+ concentration of neutrophils. The results suggest that the novel chemoattractant plays a role in neutrophil recruitment in rat inflammation.

Matrix metalloproteinase 9 level predicts optimal collagen deposition during early wound repair in humans

BACKGROUND

This study examined two matrix metalloproteinases (MMPs) and their association with deposition of collagen during wound repair.

METHODS

In 15 hernia wounds, wound fluid was collected using two Cellstick devices, which were implanted adjacent to two expanded polytetrafluoroethylene (ePTFE) tubes. MMP-2 and MMP-9 levels were analysed 24 and 48 h after operation using specific enzyme-linked immunosorbent assays, and collagen deposition in the ePTFE tubes was measured 10 days after operation as hydroxyproline.

RESULTS

The levels of both MMPs in wound fluid were increased compared with those of control serum, although MMP-9 decreased (P < 0.01) in the wounds 24-48 h after operation. The MMP-9 level at 24 h correlated inversely and specifically to deposited collagen measured as hydroxyproline (rs = -0.80, P < 0.01).

CONCLUSION

These results indicate that the level of MMP-9 in the early inflammatory phase can predict the amount of collagen deposited later in the wound healing process.

Action of metalloproteinases on porcine dentin mineralization

Samples containing predentin and mineralized dentin involving the mineralized front (newly formed dentin) were prepared by scraping developing porcine teeth after odontoblastic cell debris had been removed from the predentin surfaces. An extract was obtained separately from the matrices of predentin and of the newly formed dentin with a 4 M guanidine solution before and after demineralization with acetic acid solution. Enzymography detected 56 and 61 kDa gelatinases and 25 kDa proteoglycanase as neutral metalloproteinases in both extracts and proved them to be in an active form. Approximately half of the 56 and 61 kDa gelatinases binds to collagen fibers in predentin matrix. Three high molecular weight proteoglycans (70-85 kDa, 130-180 kDa, and 290 kDa) were found in the predentin matrix, but not in the newly formed dentin. The proteoglycanases in predentin degraded 290 kDa proteoglycan, if incubated together with calcium (Ca) ions. The results of this investigation indicate that active proteoglycanases which existed in the predentin perform no substantial work in proteoglycan degradation because the Ca ions are masked in the predentin matrix by coexisting proteoglycans. When mineralization occurs, however, they can degrade the proteoglycan at the mineralization front because excess Ca ions may be supplied via odontoblastic processes.

Gelatinase activity during wound healing

The two known mammalian gelatinases, 72- and 92-kDa gelatinase, are extracellular matrix metalloproteinases (MMPs) with a potential role in wound healing. The gelatinase activity as a function of wound age was analysed in tissue extracts of partial- and full-thickness wounds in the skin of pigs, using two assay systems. Total gelatinase activity, assessed using a 3H-labelled gelatin assay, was highest in the early healing phases and then decreased as healing proceeded in both wound types. Gelatin zymography, which distinguishes the activities of the two gelatinases, showed that the 92-kDa (MMP-9) gelatinase essentially followed the same pattern as that of total gelatinase activity, whereas the activity of the 72-kDa gelatinase (MMP-2) remained fairly stable, although it was higher than in uninjured skin, over the experimental period, irrespective of wound type. In conclusion, the two gelatinases appear to have different functions in the wound healing process. The 72-kDa gelatinase (MMP-2) is important during the prolonged remodelling phase, whereas the 92-kDa gelatinase (MMP-9) is linked to the epithelialization process and early repair events.

Inactivation of substance P by granulation tissue-derived gelatinase

An active gelatinase has been purified from the conditioned medium of granulation tissue culture formed by carrageenin injection in rats. The purified gelatinase gave a single band corresponding to a M(r) of 57 kDa on both sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and SDS-gelatin PAGE. The granulation tissue-derived gelatinase selectively cleaved the Gln6-Phe7 bond of substance P (SP) with a Km of 0.17 mM and a Vmax of 0.027 nmol SP7-11/min/micrograms protein, resulting in the generation of biologically inactive fragments, SP1-6 and SP7-11. Our data suggest that the gelatinase produced by granulation tissue participates in the inactivation of SP in the inflammatory site.

An active neutral metalloproteinase bound to the insoluble collagen in the mineralized phase matrix of adult rat calvaria

Two kinds of proteinases were found in the mineralized phase matrix of 24-week-old rat calvaria by means of enzymography using gelatin as a substrate. One proteinase was a neutral thiol 58kD proteinase as shown in a previous paper [2]. The other was a neutral metalloproteinase that had a molecular mass of 56kD and was detected only when calcium (Ca) ions were added to the incubation buffer. It is believed that the 56kD proteinase is bound to the insoluble collagen of the bone matrix, as it is solubilized by 4 M guanidine HC1 solution from the insoluble collagen fraction, when prepared by removing extractable proteins of the mineralized phase matrix. The insoluble collagen fraction could also be solubilized and prepared as gelatin by heating at 65 degrees C for 5 minutes. The gelatin was then incubated at 37 degrees C without further treatment and became degraded without an activation of 4-aminophenylmercuric acetate (APMA). This nonactivated degradation was enhanced by adding Ca ions. These results suggest that the 56kD metalloproteinase bound to the insoluble collagen of bone matrix is in an active form and may participate in the rapid degradation of collagen during bone resorption. As partially purified 56kD metalloproteinase degraded cartilage type proteoglycan, but not type I, IV, and V collagens, it is possibly related to the degradation of proteoglycans before it binds to collagen fibers during bone formation.