Dual Role of IGF2BP2 in Osteoimmunomodulation during Periodontitis

Periodontitis is a complex disease characterized by distinct inflammatory stages, with a peak of inflammation in the early phase and less prominent inflammation in the advanced phase. The insulin-like growth factor 2-binding proteins 2 (IGF2BP2) has recently been identified as a new m6A reader that protects m6A-modified messenger RNAs (mRNAs) from decay, thus participating in multiple biological processes. However, its role in periodontitis remains unexplored. Here, we investigated the role of IGF2BP2 in inflammation and osteoclast differentiation using a ligature-induced periodontitis model. Our findings revealed that IGF2BP2 responded to bacterial-induced inflammatory stimuli and exhibited differential expression patterns in early and advanced periodontitis stages, suggesting its dual role in regulating this disease. Depletion of Igf2bp2 contributed to increased release of inflammatory cytokines, thereby exacerbating periodontitis after 3 d of ligature while suppressing osteoclast differentiation and ameliorating periodontitis after 14 d of ligature. Mechanistically, we demonstrated that IGF2BP2 directly interacted with Cd5l and Cd36 mRNA via RNA immunoprecipitation assay. Overexpression of CD36 or recombinant CD5L rescued the osteoclast differentiation ability of Igf2bp2-null cells upon lipopolysaccharide stimulus, and thus the downregulation of Cd36 and Cd5l effectively reversed periodontitis in the advanced stage. Altogether, this study deepens our understanding of the potential mechanistic link among the dysregulated m6A reader IGF2BP2, immunomodulation, and osteoclastogenesis during different stages of periodontitis.

[Preliminary study on centrifugation time of liquid plasmatrix for soft tissue regeneration]

Objective: To provide reference for clinical application of liquid plasmatrix, and to investigate the optimal centrifugation time of liquid plasmatrix prepared by horizontal centrifugation for soft tissue regeneration from the aspects of mechanical properties, biological properties, and the effect of promoting soft tissue regeneration. Methods: Venous blood was collected from 6 healthy volunteers [3 males and 3 females, aged (26±2) years, with informed consent] who volunteered to donate blood at School of Stomatology, Wuhan University from September to November 2021. The collected venous blood was centrifuged at 500 ×g for 3, 5, 8 and 12 min to obtain liquid plasmatrix. The volume, weight, solidification time, and mechanical properties of liquid plasmatrix prepared at different centrifugation time were measured and recorded (the sample size at each time point was 3). The microstructure of different groups of liquid plasmatrix clot was observed by scanning electron microscope (SEM). The rheological properties of each group of liquid plasmatrix clot were measured by rheological test. The number and concentration of cells in the whole blood group and in each liquid plasmatrix group were measured using complete blood count test. The distribution of cells in the liquid plasmatrix clots was observed by hematoxylin-eosin staining. The effect of control group (Dulbecco's modified Eagle's medium containing 20% fetal bovine serum) and liquid plasmatrix clot exudates in 3, 5, 8, 12 min group (the sample size at each time point was 3) on gingival fibroblast migration was detected by cell migration method. Finally, the effects of control group and liquid plasmatrix clot exudates on the morphology of gingival fibroblasts were observed by fluorescence microscope. Results: The volume of liquid plasmatrix in 3, 5, 8 and 12 min group were approximately (2.47±0.12), (2.67±0.12), (3.53±0.12) and (3.73±0.12) ml, respectively. The weight of liquid plasmatrix in 3, 5, 8 and 12 min group were approximately (0.35±0.01), (0.46±0.02), (0.88±0.06) and (1.03±0.01) g, respectively. The maximum tensile force of liquid plasmatrix clots in 3, 5, 8 and 12 min group were (0.55±0.03), (0.56±0.03), (1.31±0.05) and (1.38±0.02) N, respectively. SEM results showed that the fibers inside the liquid plasmatrix clot became denser with increased centrifugation time. Compared with other groups, the concentrations of leukocytes, neutrophils, monocytes and lymphocytes in 8 min group were the highest, and the distribution of cell was more even. Compared with other groups, the efficiency of stimulating gingival fibroblast migration in 8 min group was the best (1.60±0.01). Fluorescence staining test showed that the liquid plasmatrix clot exudates could make gingival fibroblasts more stretched compared with control group. Conclusions: The present study shows that liquid plasmatrix prepared by centrifugation with 500 ×g centrifugal force for 8 min has higher concentration of viable cells and the ability to promote the migration of gingival fibroblasts.

New Solid-State Fermentation Chamber for Bulk Production of Aerial Conidia of Fungal Biocontrol Agents on Rice

A novel solid-state fermentation apparatus, namely an upright multi-tray conidiation chamber, was developed to facilitate the production of aerial conidia of fungal biocontrol agents, such as Beauveria bassiana. The chamber with 25 bottom-meshed metal trays had a capacity of > or =50 kg rice with each tray holding > or =2 kg. In repeated trials, a mean yield of 2.4 (1.8-2.7) x 10(12) conidia kg(-1) rice was harvested from the 7-day cultures of B. bassiana in a fully loaded chamber. The new apparatus has a high potential for bulk production of fungal conidia.

Selective effect of tempol on renal medullary hemodynamics in spontaneously hypertensive rats

The present study assessed the short- and long-term effect of tempol, a membrane-permeable mimetic of superoxide dismutase, on renal medullary hemodynamics in spontaneously hypertensive rats (SHR). Tempol was given in the drinking water (1 mM) for 4 days or 7 wk (4-11 wk of age), and medullary blood flow (MBF) was measured over a wide range of renal arterial pressure by means of laser-Doppler flowmetry in anesthetized rats. In addition, the response of the medullary circulation to angiotensin II (5-50 ng x kg(-1) x min(-1) iv) was determined in SHR treated for 4 days with tempol. Compared with control SHR, short- and long-term treatment with tempol decreased arterial pressure by approximately 20 mmHg and increased MBF by 35-50% without altering total renal blood flow (RBF) or autoregulation of RBF. Angiotensin II decreased RBF and MBF dose dependently (approximately 30% at the highest dose) in control SHR. In SHR treated with tempol, angiotensin II decreased RBF (approximately 30% at the highest dose) but did not alter MBF significantly. These data indicate that the antihypertensive effect of short- and long-term administration of tempol in SHR is associated with a selective increase in MBF. Tempol also reduced the sensitivity of MBF to angiotensin II. Taken together, these data support the idea that tempol enhances vasodilator mechanisms of the medullary circulation, possibly by interacting with the nitric oxide system. Increased MBF and reduced sensitivity of MBF to angiotensin II may contribute to the antihypertensive action of tempol in SHR.

[Optional growth medium and conditions for mass production of Pandora delphacis mycelia in submerged culture]

The entomophthoraceous fungi are important microbial control agents for insect control but their mass production is usually difficult and expensive. To produce in large quantity the mycelia of the entomophthoraceous fungus, Pandora delphacis (isolate F95129), this study was aimed at replacing expensive components of liquid medium that is usually used in laboratory only with cheap materials easily available. Based on comparative experiments with primary components of several media designed and optional conditions for submerged culture, an appropriate medium was recognized that included(per liter) 10 g of homemade yeast extract, 10 g industrial fish meal, 10 g wheat bran, 15 g corn meal, 1.0 g KH2PO4, 3.0 g NH4NO3, and 0.25 g MgSO(4).7H2O. The optional conditions for submerged culture was 25-30 degrees C, initial pH 6.5, and 40% (V/V) of flask filled with the medium and 10% of initial inoculum (liquid culture containing mycelia) for inoculation. Using the selected medium and the conditions considered, 48 h culture resulted in a considerably high yield of dry mycelia(> 25 mg/mL) with desirable capacity of spore production.

Abnormal renal medullary response to angiotensin II in SHR is corrected by long-term enalapril treatment

This study tested the hypotheses that renal medullary blood flow (MBF) in spontaneously hypertensive rats (SHR) has enhanced responsiveness to angiotensin (ANG) II and that long-term treatment with enalapril can correct this. MBF, measured by laser Doppler flowmetry in anesthetized rats, was not altered significantly by ANG II in Wistar-Kyoto (WKY) rats, but was reduced dose dependently (25% at 50 ng. kg(-1). min(-1)) in SHR. Infusion of N(G)-nitro-L-arginine methyl ester (L-NAME) into the renal medulla unmasked ANG II sensitivity in WKY rats while L-arginine given into the renal medulla abolished the responses to ANG II in SHR. In 18- to 19-wk-old SHR treated with enalapril (25 mg. kg(-1). day(-1) when 4 to 14 wk old), ANG II did not alter MBF significantly, but sensitivity to ANG II was unmasked after L-NAME was infused into the renal medulla. Endothelium-dependent vasodilation (assessed with aortic rings) was significantly greater in treated SHR when compared with that in control SHR. These results indicate that MBF in SHR is sensitive to low-dose ANG II and suggest that this effect may be due to an impaired counterregulatory effect of nitric oxide. Long-term treatment with enalapril improves endothelium-dependent vascular relaxation and decreases the sensitivity of MBF to ANG II. These effects may be causally related to the persistent antihypertensive action of enalapril in SHR.

Modeling and biological implication of time-dose-mortality data for the entomophthoralean fungus, zoophthora anhuiensis, on the green peach aphid myzus persicae

The entomophthoralean fungus Zoophthora anhuiensis frequently causes epizootics in populations of the green peach aphid, Myzus persicae, infesting cruciferous crops in the middle and lower regions of the Changjiang River, China, during late autumn and early winter. In this study, a bioassay was conducted by exposing aphids on detached leaves to varying doses of Z. anhuiensis conidia discharged from in vitro cultures. Ten doses (1.5-198 conidia/mm2) were used, with each dose including 64-120 aphids. The aphids were maintained at 18 degreesC under a photophase of 12:12 (L:D) and observed daily for mortality. The resulting time-dose-mortality data fitted well to a conditional mortality probability model based on the Hosmer-Lemeshow test (C = 9.52, df = 8, P = 0.70), resulting in a cumulative mortality probability model. The parameters from the latter model were used to estimate the lethal dose (LD50) and time (LT50) for the fungal species against the pest. The LD50 values were 87, 44, and 34 conidia/mm2 on days 5, 6, and 7 after exposure, respectively. The estimates of the LT50 values decreased from 6.7 days at 37 conidia/mm2 to 4.5 days at 198 conidia/mm2. The results indicate that Z. anhuiensis could be a promising aphid pathogen for microbial control competitive with other Zoophthora species. The model is recommended for use in the analysis of time-dose-mortality data for fungus-insect associations. The biological implications of the parameters and the advantages of the modeling technique over the conventional method of probit analysis are discussed. Copyright 1998 Academic Press.

Midazolam produces vasodilation by mixed endothelium-dependent and -independent mechanisms

Aortic rings were obtained from rat thoracic aorta and studied in vitro with and without functionally intact endothelium to determine whether "the mechanism" requires endothelium [or endothelium-derived relaxing factor (EDRF)]. In aortic rings precontracted with either phenylephrine (PE, 3 x 10(-8)-3 x 10(-7) mol/L) or KCl (40 mmol/L), midazolam produced concentration-dependent relaxation, with and without endothelium. Rings without endothelium demonstrated significantly less relaxation than those with endothelium regardless of whether they were precontracted with PE or KCl. With intact endothelium, midazolam produced greater relaxation in PE-contracted aortic rings than in KCl-contracted aortic rings; the midazolam concentration producing 50% relaxation from the contracted state (RC50) was 8.8 +/- 3.6 x 10(-7) mol/L for PE-contracted rings and 3.3 +/- 1.1 x 10(-6) mol/L for KCl-contracted rings (P < 0.05). In aortic rings with intact endothelium pretreated with NG-monomethyl-L-arginine (L-NMMA, 10(-4) mol/L), an inhibitor of nitric oxide (NO) synthesis, midazolam produced relaxation of similar magnitude to that seen in the denuded aortic rings except at the highest concentration (1 x 10(-5) mol/L). Pretreatment with the cyclooxygenase inhibitor, indomethacin (2.5 x 10(-5) mol/L), did not change the midazolam-induced relaxation in rings with intact endothelium as compared to untreated control aortic rings. In contrast to the intact endothelium state, when endothelium was removed, midazolam produced greater relaxation in the KCl-contracted aortic rings than in PE-contracted rings (RC50, 1.2 +/- 0.3 x 10(-5) mol/L vs 2.3 +/- 0.4 x 10(-5) mol/L, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)