Masaharu Makimura

IL-6 and soluble IL-6 receptor stimulate the production of MMPs and their inhibitors via JAK-STAT and ERK-MAPK signalling in human chondrocytes

Elevated concentrations of IL‐6 (interleukin‐6) and sIL‐6r (soluble IL‐6 receptor) in the synovial fluid and serum of patients with arthritis have been implicated in joint cartilage destruction. This study examined the effects of IL‐6 and sIL‐6r on the expression of MMPs (matrix metalloproteinases), TIMPs (tissue inhibitor of metalloproteinases), the plasminogen activation system including tPA (tissue‐type PA), uPA (urokinase‐type PA) and PAI‐1 (PA inhibitor type 1) using chondrocytes derived from normal human femur cartilage. The cells were cultured with or without 50 ng/ml IL‐6 and/or 30 ng/ml sIL‐6r in the presence or absence of the JAK3 (Janus kinase 3) inhibitor WHI‐P131 or the MEK [MAPK (mitogen‐activated protein kinase)/ERK (extracellular signal protein kinase) kinase] inhibitor PD98059 for up to 28 days. The expression of MMPs, TIMPs, uPA, tPA and PAI‐1 was investigated at the mRNA and protein levels. MMP protein expression and pSTAT3 (phosphorylation of signal transducer and activator of transcription 3) and pERK (phosphorylation of ERK) were also measured. Treatment with both IL‐6 and sIL‐6r markedly increased the expression of MMP‐1, MMP‐13, TIMP‐1 and PAI‐1, while significantly decreasing the expression of tPA and uPA and stimulating pSTAT3 and pERK. Adding WHI‐P131 or PD98059 decreased IL‐6 and sIL‐6r enhancement of MMP‐1, −3 and −13. The results suggest that IL‐6 and sIL‐6r stimulate the production of MMPs and their inhibitor via JAK—STAT and ERK—MAPK signalling in chondrocytes.

A novel selective medium for isolation of Aggregatibacter (Actinobacillus) actinomycetemcomitans

BACKGROUND AND OBJECTIVE Conventional selective media have been used for the selection of Aggregatibacter (Actinobacillus) actinomycetemcomitans in clinical samples. The proportion of A. actinomycetemcomitans grown on the selective media in vitro may not reflect the true counts in vivo because of the low selectivity. A novel selective medium, designated AASM, was developed for the isolation of A. actinomycetemcomitans. MATERIAL AND METHODS AASM was prepared by adding of 200 microg/mL of vancomycin and 10 U/mL of bacitracin to AAGM, which contains dextrose, sodium bicarbonate, trypticase soy, yeast extract and agar. Clinical efficacy was evaluated by the recovery, on AASM, of A. actinomycetemcomitans from subgingival samples of 44 periodontally healthy subjects and 76 patients with chronic periodontitis. RESULTS All serotypes (a-f) of A. actinomycetemcomitans strains grew well, and the average growth recovery of A. actinomycetemcomitans on AASM medium was 94.4% (80.0-109.7%) of that on AAGM. The exclusive rate of other bacteria was 99.9% in clinical samples cultured on AASM. A. actinomycetemcomitans was not detected in periodontally healthy persons but was detected in 25 (32.9%) patients with chronic periodontitis. The predominant serotype was c, detected in 11 subjects. CONCLUSION The new selective medium, AASM, was highly selective for A. actinomycetemcomitans, eliminated possible false-positive results and was useful for the isolation of A. actinomycetemcomitans from clinical samples.

Transcutaneous Immunization with the Outer Membrane Protein of P. gingivalis Elicits Long-term Protective Immunity in the Oral Cavity

A previous study showed that transcutaneous immunization with the 40-kDa outer membrane protein of Porphyromonas gingivalis (40k-OMP) elicits humoral immunity that protects from abscess induction by P. gingivalis. In this study, we assessed the potential of 40k-OMP as a transcutaneous vaccine against oral P. gingivalis infection. Transcutaneous immunization of mice with 40k-OMP alone or 40k-OMP plus cholera toxin (CT) elicited 40k-OMP-specific IgG and IgA antibody (Ab) responses in serum and IgG Abs in saliva. These Ab responses were maintained for at least 1 year after immunization, except for serum IgA Abs induced by 40k-OMP alone. Importantly, IgG Abs generated by transcutaneous immunization with 40k-OMP alone, or with 40k-OMP plus CT, inhibited hemagglutinating activity of P. gingivalis. Furthermore, mice transcutaneously immunized with 40k-OMP plus CT, but not 40k-OMP alone, showed significant reduction of alveolar bone loss caused by oral infection with P. gingivalis even 1 year after immunization. These results suggest that 40k-OMP is an effective transcutaneous vaccine against P. gingivalis infection and may be an important tool for the prevention of chronic periodontitis.