Differential Expression and Roles of Secreted Frizzled-Related Protein 5 and the Wingless Homolog Wnt5a in Periodontitis

The Wingless/integrase-1 (Wnt) family of protein ligands and their functional antagonists, secreted frizzled-related proteins (sFRPs), regulate various biological processes ranging from embryonic development to immunity and inflammation. Wnt5a and sFRP5 comprise a typical ligand/antagonist pair, and the former molecule was recently detected at the messenger RNA (mRNA) level in human periodontitis. The main objective of this study was to investigate the interrelationship of expression of Wnt5a and sFRP5 in human periodontitis (as compared to health) and to determine their roles in inflammation and bone loss in an animal model. We detected both Wnt5a and sFRP5 mRNA in human gingiva, with Wnt5a dominating in diseased and sFRP5 in healthy tissue. Wnt5a and sFRP5 protein colocalized in the gingival epithelium, suggesting epithelial cell expression, which was confirmed in cultured human gingival epithelial cells (HGECs). The HGEC expression of Wnt5a and sFRP5 was differentially regulated by a proinflammatory stimulus (lipopolysaccharide [LPS] from Porphyromonas gingivalis) in a manner consistent with the clinical observations (i.e., LPS upregulated Wnt5a and downregulated sFRP5). In HGECs, exogenously added Wnt5a enhanced whereas sFRP5 inhibited LPS-induced inflammation, as monitored by interleukin 8 production. Consistent with this, local treatment with sFRP5 in mice subjected to ligature-induced periodontitis inhibited inflammation and bone loss, correlating with decreased numbers of osteoclasts in bone tissue sections. As in humans, mouse periodontitis was associated with high expression of Wnt5a and low expression of sFRP5, although this profile was reversed after treatment with sFRP5. In conclusion, we demonstrated a novel reciprocal relationship between sFRP5 and Wnt5a expression in periodontal health and disease, paving the way to clinical investigation of the possibility of using the Wnt5a/sFRP5 ratio as a periodontitis biomarker. Moreover, we showed that sFRP5 blocks experimental periodontal inflammation and bone loss, suggesting a promising platform for the development of a new host modulation therapy in periodontitis.

Inflammatory Immune Responses by Water-insoluble α-glucans

Water-insoluble α-glucans are synthesized from sucrose by glucosyltransferase-I of mutans streptococci and play an important role in the development of dental plaque. Several types of β-glucans in fungal cell wall components and water-soluble α-glucans from Streptococcus mutans are known to modulate innate immunity. In the present study, we investigated whether water-insoluble α-glucans also induced inflammatory innate immune responses. Our results showed that water-insoluble α-glucans synthesized by Streptococcus sobrinus activated mouse peritoneal exudate macrophages to produce pro-inflammatory cytokines. The immunological responses were not due to contamination by sucrose, water-soluble α-glucan, lipopolysaccharide, or peptidoglycan. Furthermore, human monocytes stimulated by water-insoluble α-glucans produced TNF-α and IL-8, while human polymorphonuclear cells were activated by water-insoluble α-glucans, resulting in chemotaxis and hydrogen peroxide production. The results demonstrated that water-soluble α-glucans modulate macrophage- and granulocyte-induced inflammatory immune responses, and suggest that inflammation induced by those α-glucans is associated with the development of periodontal diseases.

Triad stimulation frequency for cortical facilitation in cortical myoclonus

BACKGROUND

Abnormally enhanced cortical rhythmic activities have been reported in patients with cortical myoclonus. We recently reported a new triad-conditioning transcranial magnetic stimulation (TMS) method to detect the intrinsic rhythms of the primary motor cortex (M1). Triad-conditioning TMS revealed a 40-Hz intrinsic rhythm of M1 in normal subjects. In this investigation, we study the motor cortical facilitation induced by rhythmic triple TMS pulses (triad-conditioning TMS) in patients with cortical myoclonus.

METHODS

Subjects were 7 patients with cortical myoclonus (28-74 years old) and 13 healthy volunteers (30-71 years old). Three conditioning stimuli over M1 at the intensity of 110% active motor threshold preceded the test TMS at various interstimulus intervals corresponding to 10-200 Hz. The resulting amplitudes of conditioned motor evoked potentials recorded from the contralateral hand muscle were compared with those evoked by the test stimulus alone.

RESULTS

The facilitation at 25 ms (40 Hz) observed in normal subjects was absent in patients with cortical myoclonus. Instead, triad-conditioning TMS induced facilitation at a 40 ms interval (25 Hz) in cortical myoclonus.

DISCUSSIONS

This change in the timing of facilitation may be explained by a shift of the most preferential intrinsic rhythm of M1, or by some dysfunction in the interneuronal network in cortical myoclonus.

A comparison of the effect on QT interval between thiamylal and propofol during anaesthetic induction*

SUMMARY

The aim of this study was to determine the effect of thiamylal and propofol on heart rate-corrected QT (QTc) interval during anaesthetic induction. We studied 50 patients undergoing lumbar spine surgery. Patients were administered 3 microgxkg(-1) fentanyl and were randomly allocated to receive 5 mgxkg(-1) thiamylal or 1.5 mgxkg(-1) propofol as an induction agent. Tracheal intubation was performed after vecuronium administration. Heart rate, mean arterial pressure, bispectral index score, and 12-lead electrocardiogram were recorded at the following time points: just before (T1) and 2 min after (T2) fentanyl administration; 2 min after anaesthetic administration (T3); 2.5 min after vecuronium injection (T4); and 2 min after intubation (T5). Thiamylal prolonged (p < 0.0001), but propofol shortened (p < 0.0001), the QTc interval.

Effects of STN stimulation on the initiation and inhibition of saccade in Parkinson disease

OBJECTIVES

The basal ganglia (BG) play an important role in controlling saccades. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is widely used as a treatment of Parkinson disease (PD) by altering the function of the BG. Nevertheless, the effects of STN DBS on saccade performance are not fully clarified in a systematic manner. In this study, we examined the effects of bilateral STN DBS on both the initiation and inhibition of saccades in PD.

METHODS

Thirty-two patients with PD performed 4 oculomotor tasks. Two tasks (visually guided saccades and gap saccades) were reflexive and 2 (memory-guided saccades [MGS] and antisaccades) were volitional. While taking their regular doses of antiparkinsonian drugs, patients performed these tasks under 2 conditions: during DBS (DBS-on condition) and without DBS (DBS-off condition). Fifty-one age-matched subjects served as controls.

RESULTS

In the DBS-on condition, parameters of saccade initiation were improved in all tasks, with shorter latencies and increased amplitudes, except for MGS latency. STN DBS improved the ability to suppress unwanted saccades to the cue stimulus in the MGS task. However, it did not suppress prosaccades during the antisaccade task.

CONCLUSIONS

These results suggest that deep brain stimulation (DBS) of the subthalamic nucleus (STN) affects the neural pathway common to both reflexive and volitional saccades, possibly by acting on the STN-substantia nigra pars reticulata-superior colliculi pathway. STN DBS may set the functional level of the superior colliculi appropriate for both saccade initiation and inhibition through this pathway. These findings provide novel insights into the pathophysiology of Parkinson disease and may yield better treatment strategies.

Improvement of the activity of arylmalonate decarboxylase by random mutagenesis

Arylmalonate decarboxylase (EC 4.1.1.76) catalyzes enantioselective decarboxylation of alpha-aryl-alpha-methylmalonates to give optically pure alpha-arylpropionates. Recently, we have succeeded in creating a double mutant enzyme that gave opposite enantionmer as the product. Unfortunately, however, the activity of the mutant decreased far lower than that of the native enzyme. Thus, we performed the directed evolution of the mutant via the random mutagenesis method employing the mutator strain Escherichia coli XL1-Red. About 50,000 mutants were screened on color assay plate, and one mutant with higher activity was obtained. Gene analysis of this mutant indicated that the obtained enzyme had an S36N mutation in addition to its original G74C/C188S mutations. The activity of the triple mutant enzyme was tenfold higher than that of the starting doubly mutated enzyme.