acid-phosphatase and epigallocatechin-gallate

Epigallocatechin-3-gallate (EGCG) is known for its beneficial properties, including anti-inflammatory and anti-oxidative activities. Recently, reports have suggested that EGCG plays a pivotal role in regulating cytokine expression and osteoclastic activity. In the present study, we investigated whether orally administered EGCG has a therapeutic effect on ligature-induced periodontitis.. Forty-eight Sprague-Dawley rats were treated with EGCG or phosphate-buffered saline. Periodontitis was induced by tying a ligature for 7 d. After removing ligation, EGCG (200 mg/kg) or phosphate-buffered saline was administered via oral gavage on a daily basis. Rats were killed after 1, 2 and 4 wk of administration. Histologic and histomorphometric analyses, tartrate resistant acid phosphatase staining and immunohistochemistry were carried out.. In the control group, bone loss did not recover even after the causative factor of periodontitis was eliminated. On the other hand, distance from cemento-enamel junction to alveolar bone crest, long junctional epithelium and collagen destruction were reduced in the EGCG group. Decreased interleukin (IL)-6 expression was shown from the early stage of EGCG administration, followed by reduced tumor necrosis factor (TNF) expression at week 4 EGCG group. The CT area showed a higher decrease of IL-6 expression between the control and EGCG group than alveolar bone area. Downregulation of TNF and IL-6 expression led to a decrease in osteoclast number and activity, which resulted in reduced bone loss.. Systemic administration of EGCG could have a therapeutic effect on damaged periodontal tissue. Inhibited cytokine expression, including TNF and IL-6 is responsible for the reduction in osteoclast formation, osteoclastic activity and collagen destruction.

Topics: Acid Phosphatase; Alveolar Bone Loss; Alveolar Process; Animals; Anti-Inflammatory Agents; Antioxidants; Biomarkers; Catechin; Collagen; Down-Regulation; Epithelial Attachment; Immunohistochemistry; Interleukin-6; Isoenzymes; Male; Osteoclasts; Periodontitis; Random Allocation; Rats; Rats, Sprague-Dawley; Tartrate-Resistant Acid Phosphatase; Time Factors; Tooth Cervix; Tumor Necrosis Factor-alpha

Recently, a 39 amino acid peptide fragment from prostatic acid phosphatase has been isolated from seminal fluid that can enhance infectivity of the HIV virus by up to 4-5 orders of magnitude. PAP(248-286) is effective in enhancing HIV infectivity only when it is aggregated into amyloid fibers termed SEVI. The polyphenol EGCG (epigallocatechin-3-gallate) has been shown to disrupt both SEVI formation and HIV promotion by SEVI, but the mechanism by which it accomplishes this task is unknown. Here, we show that EGCG interacts specifically with the side chains of monomeric PAP(248-286) in two regions (K251-R257 and N269-I277) of primarily charged residues, particularly lysine. The specificity of interaction to these two sites is contrary to previous studies on the interaction of EGCG with other amyloidogenic proteins, which showed the nonspecific interaction of EGCG with exposed backbone sites of unfolded amyloidogenic proteins. This interaction is specific to EGCG as the related gallocatechin (GC) molecule, which shows greatly decreased antiamyloid activity, exhibits minimal interaction with monomeric PAP(248-286). The EGCG binding was shown to occur in two steps, with the initial formation of a weakly bound complex followed by a pH dependent formation of a tightly bound complex. Experiments in which the lysine residues of PAP(248-286) have been chemically modified suggest the tightly bound complex is created by Schiff-base formation with lysine residues. The results of this study could aid in the development of small molecule inhibitors of SEVI and other amyloid proteins.

Topics: Acid Phosphatase; Amino Acid Sequence; Catechin; HIV Infections; Humans; Hydrogen-Ion Concentration; Kinetics; Microscopy, Fluorescence; Molecular Sequence Data; Protein Binding; Protein Multimerization; Protein Tyrosine Phosphatases; Serum Amyloid A Protein

Alveolar bone resorption is a characteristic feature of periodontal diseases and involves removal of both the mineral and the organic constituents of the bone matrix, a process mainly carried out by multinucleated osteoclast cells. (-)-Epigallocatechin gallate, the main constituent of green tea polyphenols, has been reported to induce the apoptotic cell death of osteoclasts and to modulate caspase activation in various tumor cells. In the present study, we investigated the inhibitory effect of (-)-epigallocatechin gallate on osteoclast survival and examined if (-)-epigallocatechin gallate mediates osteoclast apoptosis via caspase activation.. The effect of (-)-epigallocatechin gallate on osteoclast survival was examined by tartrate-resistant acid phosphatase (TRAP) staining in osteoclasts differentiated from RAW 264.7 cells. In addition, we evaluated the apoptosis of osteoclasts by (-)-epigallocatechin gallate using a DNA-fragmentation assay. Involvement of caspase in (-)-epigallocatechin gallate-mediated osteoclast apoptosis was evaluated by treatment with a general caspase inhibitor, Z-VAD-FMK. Moreover, the effect of (-)-epigallocatechin gallate on the activation of caspase-3 was assessed by a colorimetric activity assay and western blotting.. (-)-Epigallocatechin gallate significantly inhibited, in a dose-dependent manner, the survival of osteoclasts differentiated from RAW 264.7 cells and induced the apoptosis of osteoclasts. Treatment with (-)-epigallocatechin gallate resulted in DNA fragmentation and induced the activation of caspase-3 in RAW 264.7 cell-derived osteoclasts. Additional treatment with Z-VAD-FMK suppressed these effects of (-)-epigallocatechin gallate.. From these findings, we could suggest that (-)-epigallocatechin gallate might prevent alveolar bone resorption by inhibiting osteoclast survival through the caspase-mediated apoptosis.

Topics: Acid Phosphatase; Alveolar Process; Amino Acid Chloromethyl Ketones; Animals; Apoptosis; Bone Resorption; Caspase Inhibitors; Caspases; Catechin; Cell Line; Cell Survival; DNA Fragmentation; Enzyme Activation; Enzyme Inhibitors; Isoenzymes; Mice; Osteoclasts; RANK Ligand; Tartrate-Resistant Acid Phosphatase