Sponges (Porifera) are the oldest living metazoan in the world, among which most of them (Demospongia) can produce silicic skeleton from orthosilicic acid in the seawater under the natural enVironmental conditions. These biosilicic materials exhibit good mechanical and optical properties as well as good biocompatibility. During the biosilicification process of sponges, a protein, named as silicatein, plays an important role and has attracted great attention from biologist, chemists and material scientists. This mini review highlights the discovery of silicateins and its function as both an enzymatic catalyst and an organic template for biosilicification. The studies since 1999 were briefly introduced on the application of silicatein as a biocatalyst and template for synthesis of silica-based and other inorganic materials. It is expected to stimulate the interests in the related researches in China.
Animals ; Biocatalysis ; Biocompatible Materials ; Cathepsins ; chemistry ; Porifera ; enzymology ; Silicon Dioxide ; metabolism

There are three different types of cell death, including apoptosis (Type I), autophagic cell death (Type II), and necrosis (Type III). Ischemic neuronal death influences stroke development and progression. Lysosomes are important organelles having an acidic milieu to maintain cellular metabolism by degrading unneeded extra- and intracellular substances. Lysosomal enzymes, including cathepsins and some lipid hydrolases, when secreted following rupture of the lysosomal membrane, can be very harmful to their environment, which results in pathological destruction of cellular structures. Since lysosomes contain catalytic enzymes for degrading proteins, carbohydrates and lipids, it seems natural that they should participate in cellular death and dismantling. In this review, we discuss the recent developments in ischemic neuronal death, and present the possible molecular mechanisms that the lysosomal enzymes participate in the three different types of cell death in ischemic brain damage. Moreover, the research related to the selective cathepsin inhibitors may provide a novel therapeutic target for treating stroke and promoting recovery.
Animals ; Apoptosis ; Autophagy ; Brain Infarction ; enzymology ; physiopathology ; Brain Ischemia ; enzymology ; physiopathology ; Cathepsins ; metabolism ; Humans ; Lysosomes ; metabolism ; Necrosis ; physiopathology ; Nerve Degeneration ; enzymology ; physiopathology ; Peptide Hydrolases ; metabolism

Cysteine and aspartic proteases possess high elastolytic activity and might contribute to the degradation of the abdominal aortic aneurysm (AAA) wall. The aim of this study was to analyze, in detail, the proteases (cathepsins B, D, K, L and S, and inhibitor cystatin C) found in human AAA and healthy aortic tissue samples. The vessel walls from AAA patients (n=36) and nonaneurysmal aortae (n=10) were retrieved using conventional surgical repair and autopsy methods. Serum samples from the same AAA patients and 10 healthy volunteers were also collected. Quantitative expression analyses were performed at the mRNA level using real-time reverse transcriptase-PCR (RT-PCR). Furthermore, analyses at the protein level included western blot and immunoprecipitation analyses. Cellular sources of cysteine/aspartic proteases and cystatin C were identified by immunohistochemistry (IHC). All cysteine/aspartic proteases and cystatin C were detected in the AAA and control samples. Using quantitative RT-PCR, a significant increase in expression was observed for cathepsins B (P=0.021) and L (P=0.018), compared with the controls. Cathepsin B and cystatin C were also detected in the serum of AAA patients. Using IHC, smooth muscle cells (SMCs) and macrophages were positive for all of the tested cathepsins, as well as cystatin C; in addition, the lymphocytes were mainly positive for cathepsin B, followed by cathepsins D and S. All cysteine/aspartic proteases analyzed in our study were detected in the AAA and healthy aorta. The highest expression was found in macrophages and SMCs. Consequently, cysteine/aspartic proteases might play a substantial role in AAA.
Aged ; Aorta/enzymology ; Aortic Aneurysm, Abdominal/*enzymology ; Aspartic Acid Proteases/genetics/*metabolism ; Case-Control Studies ; Cathepsins/genetics/metabolism ; Cysteine Proteases/genetics/*metabolism ; Humans ; Lymphocytes/enzymology ; Macrophages/enzymology ; Middle Aged ; Myocytes, Smooth Muscle/enzymology ; RNA, Messenger/genetics/metabolism

BACKGROUNDPrevious studies have indicated that thrombin (TM) may play a major role in brain edema after intracerebral hemorrhages (ICHs). However, the mechanism of TM-induced brain edema is poorly understood. In this study, we explored the effect of TM on the permeability of the blood brain barrier (BBB) and investigated its possible mechanism, aiming at providing a potential target for brain edema therapy after ICHs.

METHODSTM or TM + cathepsin G (CATG) was stereotaxically injected into the right caudate nucleus of Sprague-Dawley rats in vivo. BBB permeability was measured by Evans-Blue extravasation. Brain water content was determined by the dry-wet weight method. Brain microvascular endothelial cells were then cultured in vitro. After TM or TM + CATG was added to the endothelial cell medium, changes in the morphology of cells were dynamically observed by phase-contrast light microscopy, and the expression of matrix metalloproteinase-2 (MMP-2) protein was measured by immunohistochemical method.

RESULTSBBB permeability increased at 6 hours after a TM injection into the ipsilateral caudate nucleus (P < 0.05), peaked between 24 hours (P < 0.01) and 48 hours (P < 0.05) after the injection, and then declined. Brain water content changed in parallel with the changes in BBB permeability. However, at all time points, BBB permeability and brain water content after a TM + CATG injection were not significantly different from the respective parameters in the control group (P > 0.05). TM induced endothelial cell contraction in vitro in a time-dependent manner and enhanced the expression of MMP-2 protein. After incubation with TM + CATG, cell morphology and MMP-2 expression did not change significantly as compared to the control group (P > 0.05).

CONCLUSIONSIncreased BBB permeability may be one of the mechanisms behind TM-induced cerebral edema. TM induces endothelial cell contraction and promotes MMP-2 expression by activating protease activated receptor-1 (PAR-1), possibly leading to the opening of the BBB.

Animals ; Blood-Brain Barrier ; drug effects ; Body Water ; metabolism ; Brain Edema ; etiology ; Cathepsin G ; Cathepsins ; pharmacology ; Cerebral Hemorrhage ; complications ; Matrix Metalloproteinase 2 ; analysis ; Permeability ; Rats ; Rats, Sprague-Dawley ; Receptor, PAR-1 ; physiology ; Serine Endopeptidases ; Thrombin ; toxicity

OBJECTIVETo observe myocardial cathepsin (Cat) S expression and activity in hypertensive heart failure rats.

METHODSThe expression and activity of Cat S were determined in the left ventricular (LV) myocardium (LVM) of Dahl salt-sensitive rats fed either a high-salt (HS, 8%) or low-salt (LS, 0, 3%, controls) diet starting at age 7 weeks for 12 weeks (hypertrophy model, H-LVH) or 19 weeks (heart failure model, H-HF). Age-matched rats served as controls and human normal, hypertensive and heart failure myocardial specimen were also examined for changes on the expression and activity of Cat S.

RESULTSReverse transcription and real-time polymerase chain reaction analysis revealed significantly upregulated Cat S mRNA in rats with H-HF than in rats with H-LVH or in control rats and Cat S mRNA expression is negatively correlated with LVEF (r = -0.88, P < 0.05). In situ and immunohistochemistry examinations showed that Cat S was localized predominantly in cardiac myocytes (CMCs) and coronary vascular smooth muscle cells (SMC). Elastic lamina fragmentations and Cat S-dependent elastolytic activity were significantly increased in H-HF-rats. The expression of interleukin-1 beta was also increased in the LVM of H-HF rats, and this cytokine was found to increase the Cat S protein expression in culture neonatal CMCs. Similar results were revealed in human myocardial specimens.

CONCLUSIONElastolytic Cat S might play an important role in the pathogenesis of myocardial remodeling and heart failure and Cat S might serve as a novel therapeutic target in preventing or reversing hypertension induced LV remodeling and heart failure.

Adult ; Aged ; Animals ; Case-Control Studies ; Cathepsins ; metabolism ; Disease Models, Animal ; Enzyme Activation ; Heart Failure ; enzymology ; etiology ; physiopathology ; Humans ; Hypertension ; complications ; enzymology ; Male ; Middle Aged ; Myocardium ; enzymology ; Rats ; Rats, Inbred Dahl ; Ventricular Function, Left ; Ventricular Remodeling

Cathepsin L is a kind of cystein proteases which are known to facilitate the invasion and metastasis of tumor cells by degrading the components of basement membrane and extracellular matrix. This study was undertaken to investigate the expression of cathepsin L by Northern blot analysis with radiolabeled cDNA specific for cathepsin L in six normal tissues, two osteosarcoma cell lines, MG-63 and Saos-2, six primary bone tumors and six metastatic bone tumors. In six normal tissues, the highest level of cathepsin L was expressed in liver with the descending order of liver > lung > thymus > ovary > kidney > esophagus. One of the two osteosarcoma cell lines established from the primary sites expressed a high level of cathepsin L mRNA. Out of six primary bone tumors, three (50%) expressed cathepsin L mRNA, while all (100%) of six metastatic bone tumors expressed the mRNA. These results demonstrating the higher frequency of expression of cathepsin L in metastatic bone tumors suggest that cathepsin L may participate in tumor invasion and metastasis.
Adolescent ; Adult ; Bone Neoplasms/*genetics/*secondary ; Case-Control Studies ; Cathepsins/*metabolism ; Cysteine Endopeptidases/*metabolism ; Female ; *Gene Expression Regulation, Neoplastic ; Human ; Male ; Middle Age ; Neoplasm Invasiveness/genetics ; Neoplasm Metastasis/genetics ; Osteosarcoma/genetics ; RNA, Messenger/metabolism ; Support, Non-U.S. Gov't ; Tumor Cells, Cultured

OBJECTIVETo investigate, in vitro, the effect of cathepsins specific inhibitor N-(trans-epoxysuccinyl)-L-leucine 4-guanidinobutylamide(E-64) on dental endogenous cathepsins and to find its most effective molarity to elevate dentin-resin bonding durability.

METHODSFifty recently extracted human third molars were divided into five groups according to random number table, and treated with different molarity of E-64 as follow: 0, 2.5, 5.0, 10.0 and 20.0 µmol/L. The group 0 µmol/L was control group. Then 20 specimens of dentin-resin composite were fabricated in each group. Half of the specimens were tested after 24 h water storage(37 °C) and the other half were tested after 90 days water storage(37 °C) followed by 3000 cycles'thermocyling(5-55 °C) as aging treatment. Fractured specimens were analyzed using scanning electron microscopy(SEM).

RESULTSAfter 24 h water storage, no significant differences were found in micro-tensile bond strength(µTBS) of samples between different groups (P > 0.05). However, after ageing treatment, µTBS of the samples in group 2.5, 5.0, 10.0 and 20.0 µmol/L [(18.7 ± 2.7), (20.8 ± 3.4), (18.3 ± 2.8) and (19.1 ± 2.7) MPa] were significantly higher than that in group 0 µmol/L [(15.1 ± 3.0) MPa] (P < 0.05). Only in the group 5.0 µmol/L no significant difference was found between the original and the decreased value of µTBS(P > 0.05), while the µTBS in other groups decreased significantly after aging treatment(P < 0.05). Failure types were almost adhesive and mixed types. Collagens in hybrid layer were less degraded in the groups using E-64 after aging treatment than control group.

CONCLUSIONSE-64 was effective on inhibiting cathepsins activity in dentin, and induced less collagens degradation in smear layer for better dentin-resin bond durability.

Adolescent ; Adult ; Cathepsins ; antagonists & inhibitors ; Collagen ; metabolism ; Composite Resins ; chemistry ; Dental Bonding ; Dental Stress Analysis ; Dentin ; ultrastructure ; Dentin-Bonding Agents ; chemistry ; Dose-Response Relationship, Drug ; Humans ; Leucine ; administration & dosage ; analogs & derivatives ; pharmacology ; Microscopy, Electron, Scanning ; Molar, Third ; Random Allocation ; Tensile Strength ; Young Adult

To investigate the effect of the jianpi-jiedu formula (JPJD) on the expression of angiogenesis-relevant genes in colon cancer.
 Methods: Crude extract was obtained from JPJD by water extract method. The effect of JPJD crude extract on colon cancer cell proliferation capacity was determined by MTT assays. The IC50 value was calculated by GraphPad Prism5 software. Affymetrix gene expression profiling chip was used to detect significant differences in expressions of genes after JPJD intervention, and pathway enrichment analysis was performed to analyze the differentially expressed genes. Ingenuity Pathway Analysis software was applied to analyze differentially expressed genes relevant to tumor angiogenesis based on mammalian target of rapamycin (mTOR) signaling pathway and then the network diagram was built. Western blot was used to verify the protein levels of key genes related to tumor angiogenesis.
 Results: JPJD crud extract inhibited the proliferation capacity in colon cancer cells. The IC50 values in 24, 48, and 72 hours after treatment were 13.060, 9.646 and 8.448 mg/mL, respectively. The results of chip showed that 218 genes significantly upgraded, and 252 genes significantly downgraded after JPJD treatment. Most of the genes were related to the function of biosynthesis, metabolism, cell apoptosis, antigen extraction, angiogenesis and so on. There were 12 differentially expressed angiogenesis genes. IPA software analysis showed that the JPJD downregulated expression of sphingomyelin phosphodiesterase 3 (SMPD3), VEGF, vascular endothelial growth factor A (VEGFA), integrin subunit alpha 1 (ITGA1), cathepsin B (CTSB), and cathepsin S (CTSS) genes, while upregulated expressions of GAB2 and plasminogen activator, urokinase receptor (PLAUR) genes in the colorectal cancer cell. Western blot results demonstrated that JPJD obviously downregulated expressions of phospho-mTOR (P-mTOR), signal transducer and activator of transcription 3 (STAT3), hypoxia inducible factor-1α (HIF-1α), and VEGF proteins, while obviously upregulated the level of phospho-P53 (P-P53) protein.
 Conclusion: JPJD may inhibit colorectal tumor angiogenesis through regulation of the mTOR-HIF-1α-VEGF signal pathway.
Animals ; Blotting, Western ; Cathepsin B ; drug effects ; metabolism ; Cathepsins ; drug effects ; metabolism ; Cell Line, Tumor ; drug effects ; Colorectal Neoplasms ; blood supply ; genetics ; Down-Regulation ; Drugs, Chinese Herbal ; pharmacology ; Gene Expression Profiling ; methods ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; drug effects ; metabolism ; Integrin alpha Chains ; drug effects ; metabolism ; Neovascularization, Pathologic ; genetics ; Receptors, Urokinase Plasminogen Activator ; drug effects ; metabolism ; STAT3 Transcription Factor ; drug effects ; metabolism ; Signal Transduction ; Sphingomyelin Phosphodiesterase ; drug effects ; metabolism ; TOR Serine-Threonine Kinases ; drug effects ; metabolism ; Tumor Suppressor Protein p53 ; drug effects ; metabolism ; Up-Regulation ; Vascular Endothelial Growth Factor A ; drug effects ; metabolism