Reactive oxygen species generation required for autophagy induction during butyrate- or propionate-induced release of damage-associated molecular patterns from dying gingival epithelial Ca9-22 cells

PURPOSE

Bacterial cells in mature dental plaque produce a high concentration of short-chain fatty acids (SCFAs) such as butyrate and propionate. SCFA-treatment on human gingival epithelial Ca9-22 cells induced cell death. However, the exact mechanism underlying cell death remains unclear. In this study, the relationship between reactive oxygen species (ROS) and autophagy induction during SCFA-induced cell death was examined.

METHODS

Human gingival epithelial Ca9-22 cells were treated with butyrate or propionate to induce cell death and the number of dead cells were measured using SYTOX-green dye. A siRNA for ATG5 and N-acetylcysteine (NAC) were used for autophagy reduction and ROS-scavenging, respectively. Release of damage-associated molecular patterns (DAMPs) such as Sin3A-associated protein 130 (SAP130) and high-mobility group box 1 (HMGB1) were detected using western blot.

RESULTS

Reducing autophagy significantly suppressed SCFA-induced Ca9-22 cell death. ROS generation was observed upon SCFA treatment, and scavenging ROS with NAC decreased cell death. NAC also reduced the SCFA-induced increase in microtubule-associated protein 1 light chain 3B (LC3B)-I and LC3B-II, and mitigated the release of DAMPs.

CONCLUSION

The findings suggest that ROS generation is necessary for autophagy, which is required for SCFA-induced cell death and accompanying DAMP release.

Possible roles of short-chain fatty acids produced by oral bacteria in the development of alveolar osteitis

PURPOSE

Alveolar osteitis (dry sockets) is a painful condition characterized by a limited immune response. It is typically caused by the removal of blood clots from extracted tooth sockets, which leads to the fermentation of trapped food remnants by oral bacteria in the cavities, producing high concentrations of short-chain fatty acids (SCFAs). This study examined the effects of SCFAs on immunity and bone metabolism.

METHODS

Mouse macrophage Raw264.7 cells were treated with oral bacteria supernatants or SCFA mixtures, and inducible nitric oxide synthase (iNOS) levels were determined by western blot. The same cells were treated with SCFA mixtures in the presence of receptor activator of nuclear factor-kappa B ligand (RANKL), and osteoclast-like cells were counted. MC3T3-E1 cells were treated with SCFA mixtures and stained with alizarin red S.

RESULTS

Raw264.7 cells treated with oral bacterial culture supernatants of Porphyromonas gingivalis and Fusobacterium nucleatum inhibited lipopolysaccharide (LPS)-induced iNOS production, likely due to SCFA content. SCFA mixtures mimicking these supernatants inhibited the number of RANKL-induced tartrate-resistant acid phosphatase (TRAP)-positive cells and MC3T3-E1 cell mineralization.

CONCLUSION

These data suggest that SCFAs produced by P. gingivalis and F. nucleatum may reduce the inflammatory response and mildly induce mineralization of the alveolar walls. These results may contribute to the understanding of alveolar osteitis.

Inductive effect of SORT1 on odontoblastic differentiation of human dental pulp-derived stem cells

This study investigated the expression of sortilin 1 (SORT1) in cultured human dental pulp-derived stem cells (hDPSCs) and its role in their odontoblastic differentiation. Permanent teeth were extracted from five patients, and the dental pulp was harvested for explant culture. Fluorescence-activated cell sorting was used to analyze the outgrowth of adherent cells and cells that had migrated from the tissue margin. SORT1 expression was detected in hDPSCs simultaneously expressing the mesenchymal stem cell markers CD44 and CD90. The odontoblastic differentiation potential of SORT1-positive hDPSCs was examined via staining for alkaline phosphatase (ALP), an early odontoblastic differentiation marker. ALP staining was more intense in SORT1-positive than in SORT1-negative hDPSCs. Consistently, the expression of mRNA encoding SORT1 and p75NTR, a binding partner of SORT1, increased in SORT1-positive hDPSCs during odontoblastic differentiation. In addition, pro-nerve growth factor (NGF), a ligand for SORT1-p75NTR co-receptor, promoted ALP expression in SORT1-positive hDPSCs, and the interaction between SORT1 and p75NTR was detected using a coimmunoprecipitation assay. The function of SORT1 in odontoblastic differentiation was examined via RNA interference using shRNA targeting SORT1. ALP staining intensity in SORT1/shRNA-transfected cells was markedly lower than in control/shRNA-transfected cells. SORT1 knockdown decreased JUN phosphorylation and recruitment of phosphorylated JUN to the ALP promoter. Collectively, these results indicate that SORT1 is involved in the odontoblastic differentiation of hDPSCs through the JUN N-terminal kinases (JNK)/JUN signaling pathway and that the binding of SORT1 and p75NTR plays an important role in this process.

Clinical usefulness of a novel fluorescence technique for the intraoperative diagnosis of surgical margins in patients with breast cancer

In both 5- and 15-min data, FI was significantly higher in malignant tissues than in benign tissues. The diagnostic accuracy was similar at 5 and 15 min. Therefore, the 5-min FI was enough applying in the further analyses.

Rapamycin Accelerates Axon Regeneration Through Schwann Cell-mediated Autophagy Following Inferior Alveolar Nerve Transection in Rats

Sensory disturbance in the orofacial region owing to trigeminal nerve injury is caused by dental treatment or accident. Commercially available therapeutics are ineffective for the treatment of sensory disturbance. Additionally, the therapeutic effects of rapamycin, an allosteric inhibitor of mammalian target of rapamycin (mTOR), which negatively regulates autophagy, on the sensory disturbance are not fully investigated. Thus, we investigated the therapeutic effects of rapamycin on the sensory disturbance in the mandibular region caused by inferior alveolar nerve (IAN) transection (IANX) in rats. The expression levels of the phosphorylated p70S6K, a downstream molecule of mTOR, in the proximal and distal stumps of the transected IAN were significantly reduced by rapamycin administration to the injured site. Conversely, the increments of both Beclin 1 and microtubule-associated protein-1 light chain 3-II protein levels in the proximal and distal stumps of the transected IAN was induced by rapamycin administration. Immunohistochemical analyses revealed that Beclin 1 was located in Schwann cells in the proximal stump of the IAN. Accumulation of myelin protein zero and myelin basic protein in the proximal and distal stumps of the IAN was significantly reduced by rapamycin administration. Rapamycin administration facilitated axon regeneration after IANX and increased the number of brain-derived neurotrophic factor positive neurons in the trigeminal ganglion. Thus, recovery from sensory disturbance in the lower lip caused by IANX was markedly facilitated by rapamycin. These findings suggest that rapamycin administration is a promising treatment for the sensory disturbance caused by IANX.

Bioinformatics analysis of dysregulated exosomal microRNAs derived from oral squamous cell carcinoma cells

PURPOSE

The present study aimed to identify dysregulated exosomal miRNAs associated with diagnostic and therapeutic biomarkers in oral squamous cell carcinoma (OSCC).

METHODS

Microarray analysis was used to compare expression profiles of exosomal miRNAs in the OSCC-derived cell lines HSC-2, HSC-3, Ca9-22, and HO-1-N1 with those in human normal keratinocytes (HNOKs). The identified OSCC-related miRNAs and their potential target genes were analyzed with bioinformatic analyses, and the data were subjected to Ingenuity Pathway Analysis (IPA) to clarify functional networks and gene ontologies of the identified exosomal miRNAs secreted by OSCC cells.

RESULTS

Comparison with HNOKs detected 8 upregulated and 12 downregulated miRNAs in OSCC-secreted exosomes. The potential target mRNAs of these dysregulated miRNAs were suggested by IPA, and 6 significant genetic networks were indicated by genetic network analysis. Furthermore, 4 crucial upstream miRNAs-miR-125b-5p, miR-17-5p, miR-200b-3p, and miR-23a-3p-were identified. miR-125b-5p was a central node in the most significant network. Gene ontology analysis showed significant enrichment of genes with cancer-related functions, such as molecular mechanisms of cancer, cell cycle, and regulation of the epithelial-mesenchymal transition.

CONCLUSION

These results provide a comprehensive view of the functions of dysregulated exosomal miRNAs in OSCC, thus illuminating OSCC tumorigenesis and development.

Reactive oxygen species-dependent release of damage-associated molecular patterns from human gingival epithelial Ca9-22 cells during butyrate or propionate exposure

Treating the gingival epithelial Ca9-22 cell with butyrate, a short-chain fatty acid (SCFA) produced by bacteria within mature dental plaque, induces necrotic cellular death. In this report, it was examined whether SCFA-mediated cellular death is accompanied by a release of damage-associated molecular patterns (DAMPs). In addition, the role of reactive oxygen species (ROS) in the release of DAMPs was evaluated. Human gingival epithelial Ca9-22 cells were treated with butyrate or propionate. The amounts of dead cells were then measured using SYTOX-green dye. Released DAMPs were detected by western blot. The role of ROS scavengers, ascorbic acid and N-acetylcysteine, on DAMP-release was evaluated. Dose and time-dependent induction of Ca9-22 cell death was observed during butyrate and propionate treatments. This was accompanied by the release of DAMPs. Ascorbic acid or N-acetylcysteine reduced cellular death and inhibited DAMP-release induced by exposure to butyrate or propionate. These data collectively suggest that SCFA-induced death of gingival epithelial Ca9-22 cells and accompanying release of DAMPs are dependent on ROS.

Menthol-induced facilitation of cerebrocortical excitatory propagation induced by air puff stimulation of the nasal cavity in the rat: An optical imaging study

Temperature plays a critical role in the sensation of airflow in the nasal mucosa. Neural activities of the ethmoidal nerve, a trigeminal afferent, responding to airflow are suppressed by warm airflow, whereas cold airflow enhances the ethmoidal nerve activities, which is mimicked by application of menthol, a cold-sensitive TRPM8 receptor agonist. However, it has been an open issue how menthol modulates the spatiotemporal profiles of neural activities of somatosensory cortical neurons. In this study, we assessed neural responses to an air puff stimulation (100 ms) to the nasal cavity in the absence or presence of l-menthol using an optical imaging technique with a voltage-sensitive dye in the primary cortex (S1) of urethane-anesthetized rats. A weak air puff application (15 psi) without l-menthol induced neural excitation in a part of the contralateral S1. The air puff stimulation with l-menthol significantly increased the optical signal intensity, expanded the activated area, and shortened the latency, compared to those in the absence of l-menthol. These results suggest that activation of cold-sensitive TRPM8 receptors sharpens airflow sensation in the nasal cavity and expands the receptive field, especially toward the pharynx, which may contribute to enhanced flavor perception.

Relationship between the fluorescence intensity of rhodamine-labeled orexin A and the calcium responses in cortical neurons: An in vivo two-photon calcium imaging study

Neural responses to a ligand vary widely between neurons; however, the mechanisms underlying this variation remain unclear. One possible mechanism is a variation in the number of receptors expressed in each neural membrane. Here, we synthesized a rhodamine-labeled orexin A compound, enabling us to quantify the amount of orexin binding to its receptors, OX₁ and OX₂, which principally couple to the G_q/11 protein. The rhodamine intensity and calcium response were measured under tetrodotoxin application from insular cortical glutamatergic neurons in Thy1-GCaMP6s transgenic mice using an in vivo two-photon microscope. Applying rhodamine-labeled orexin A (10 μM) to the cortical surface gradually and heterogeneously increased both the intensity of the rhodamine fluorescence and [Ca²⁺]_i. Calcium responses started simultaneously with the increase in rhodamine-labeled orexin fluorescence and reached a plateau within several minutes. We classified neurons as high- and low-responding neurons based on the peak amplitude of the [Ca²⁺]_i increase. The rhodamine fluorescence intensity was larger in the high-responding neurons than the low-responding neurons. Preapplication of SB334867 and TCS-OX₂-29, OX₁ and OX₂ antagonists, respectively, decreased the proportion of high-responding neurons. These results suggest that the diverse receptor expression level in neural membranes is involved in mechanisms underlying varied neural responses, including [Ca²⁺]_i increases.

CAY10591, a SIRT1 activator, suppresses cell growth, invasion, and migration in gingival epithelial carcinoma cells

SIRT1 is a NAD-dependent histone deacetylase that is important in a wide variety of physiological and pathophysiological processes. Although many studies have examined the relationship between SIRT1 and cancer, the role of SIRT1 in tumor malignancy is controversial. Here, we examined the effects of the SIRT1 activator CAY10591 in gingival epithelial carcinoma Ca9-22 cells. CAY10591 treatment dose- and time-dependently increased SIRT1 level and activity. The treatment decreased cell growth and induced cell-cycle repressor p21 levels. In addition, dimethyl sulfoxide significantly reduced cellular invasion and migration, and CAY10591 enhanced this decrease. Quantitative PCR analysis showed that CAY10591 decreased expression of several invasion/migration promoter genes and induced repressor genes. Our findings suggest that CAY10591 suppresses cell growth and invasion/migration activity in gingival squamous cell carcinoma Ca9-22 cells.

Abstract P2-11-11: Role of postmastectomy radiotherapy after neoadjuvant chemotherapy in breast cancer patients: A study from the Japanese breast cancer registry

Background:

Postmastectomy radiotherapy (PMRT) has been shown to be beneficial in node-positive breast cancer patients. However, the role of PMRT for patients receiving modern neoadjuvant chemotherapy (NAC) are controversial. We aimed to evaluate the efficacy of radiotherapy for breast cancer patients treated with NAC and mastectomy in the Japanese Breast Cancer Registry.

Methods:

Patients who received NAC and mastectomy for cT1-4 cN0-2 M0 breast cancer were included in this analysis. We assessed locoregional recurrence (LRR), distant disease-free survival (DDFS), and overall survival (OS) using the Kaplan-Meier method and compared them between the groups with and without PMRT by nodal status after NAC; ypN0, ypN1, and ypN2-3. We also performed multivariable cox regression analysis to evaluate the association of radiotherapy and these outcomes adjusting for baseline patient and cancer characteristics.

Results:

Of the 145,530 patients registered from 2004 to 2009, we identified 3,226 patients who met our inclusion criteria with the 5-year follow-up information including 1,299 ypN0, 1,036 ypN1, and 879 ypN2-3 cases. PMRT was performed in 185 patients (14.2%) with ypN0, 265 patients (25.6%) with ypN1, and 543 patients (61.8%) with ypN2-3. There was no difference in LRR, DDFS, and OS between the groups with and without radiotherapy for ypN1 patients who received NAC (P=0.72, P=0.29, and P=0.36, respectively). For patients with ypN2-3 breast cancer, radiotherapy significantly improved LRR (P<0.001), DDFS (P=0.01), and OS (P<0.001) on univariate analysis. No difference in LRR, DDFS, and OS was observed for ypN0 patients (P=0.81, P=0.15, and P=0.05, respectively). In multivariable analysis, the use of radiotherapy was independently associated with improved LRR [hazard ratio (HR): 0.608, 95% confidence interval (CI): 0.452–0.818, P=0.001] and OS [HR: 0.685, 95% CI: 0.531–0.885, P=0.004] for ypN2-3 patients.

Effect of PMRT on locoregional recurrence by the ypN subgroupsypN subgroupHazard ratio95%CI Low95%CI HighP valueypN00.8550.4581.5960.623ypN10.8320.5491.2620.387ypN2-30.6080.4520.8180.001

Visualization and automatic detection of defect distribution in GaN atomic structure from sampling Moiré phase

Quantitative detection of defects in atomic structures is of great significance to evaluating product quality and exploring quality improvement process. In this study, a Fourier transform filtered sampling Moiré technique was proposed to visualize and detect defects in atomic arrays in a large field of view. Defect distributions, defect numbers and defect densities could be visually and quantitatively determined from a single atomic structure image at low cost. The effectiveness of the proposed technique was verified from numerical simulations. As an application, the dislocation distributions in a GaN/AlGaN atomic structure in two directions were magnified and displayed in Moiré phase maps, and defect locations and densities were detected automatically. The proposed technique is able to provide valuable references to material scientists and engineers by checking the effect of various treatments for defect reduction.

Isolated astasia caused by a localized infarction in the suprathalamic white matter

A 73‐year‐old woman with essential hypertension and diabetes mellitus abruptly developed astasia. There were no other neurological abnormalities. Cranial diffusion‐weighted magnetic resonance imaging demonstrated a localized infarction in the right‐sided suprathalamic white matter. Under antiplatelet agent and rehabilitation, the patient became asymptomatic within 4 days. This is a first reported case of isolated astasia due to a suprathalamic white matter infarction. We speculated that disruption of the connection from the ventrolateral nucleus of the thalamus to the posterior cingulate gyrus and/or supplementary motor area might cause astasia.

Involvement of the calcium-sensing receptor in mineral trioxide aggregate-induced osteogenic gene expression in murine MC3T3-E1 cells

Mineral trioxide aggregate (MTA) has excellent biocompatibility as well as bioactivity, including an ability to induce osteoblast differentiation. We examined the effects of the calcium-sensing receptor (CaSR) on osteogenic gene expression induced by MTA. MC3T3-E1 cells were cultured with or without (control) MTA. The expression levels of Runx2, type I collagen, and CaSR genes were analyzed by real-time polymerase chain reaction and their products were measured using enzyme-linked immunosorbent assays. The levels were increased significantly in cells exposed to MTA compared with control. Next, MC3T3-E1 cells were cultured with MTA and EGTA (a calcium chelator), because calcium ions were released continuously from MTA into the culture. Expression levels were decreased to control levels by MTA plus EGTA. NPS2143 (a CaSR antagonist) also reduced MTA-induced gene expression. These results suggest that MTA induced osteogenic gene expressions of Runx2 and type I collagen via CaSR in MC3T3-E1 cells.

Abstract P3-13-17: A multi-center prospective study of radiofrequency ablation therapy for small breast carcinomas

Background: As the management of breast carcinoma evolves toward less invasive treatments, the next step is the possibility of removing the primary tumor without surgery. The most promising noninvasive ablation technique is radiofrequency ablation (RFA), which can effectively kill tumor cells with a low complication rate. Our preliminary studies of RFA followed by standard surgical resection have indicated that this technique is effective for surgical ablation of small (≤ 2cm) breast tumors without extensive intraductal components (EIC).

Methods: To determine if RFA is oncologically and cosmetically appropriate for the local treatment of primary breast carcinoma, this multi-center prospective study used RFA as the sole local treatment of breast tumors ≤ 1.5cm in size on ultrasound and MRI. Exclusion criteria include receiving of preoperative chemotherapy, or the presence of invasive lobular carcinoma or invasive ductal carcinoma with suspicious EIC. After confirmation that the standard baseline core biopsy for diagnosis and measurement of tumors markers (ER, PgR, HER-2/neu expression and the presence of the Ki-67 proliferative marker) have been obtained, consent will be obtained and the patient scheduled RFA. All patients received adjuvant radiation therapy. The use and choice of systemic therapy will be based on the information from the baseline core biopsy. The first primary endpoints of this study is successful tumor ablation, as evidenced by negative findings on vacuum-assisted or core biopsies and imaging studies after RFA. The second primary endpoints is the incidence of procedure related adverse events. Forty patients with small tumors that are clearly identifiable and measurable by ultrasound and MRI were enrolled. The response to ablation was evaluated with both vacuum-assisted or core biopsies and imaging studies every 3 months during the first year. The long-term outcomes were assessed using quality of life measurement scales and imaging studies every 6 months thereafter through year 5.

Results: Of the 58 patients who participated in this study, 55 completed the protocol. In 48 of the 55 (87%) treated patients, successful tumor ablation, as determined by negative findings on vacuum-assisted or core biopsies and imaging studies, was confirmed. The remaining 7 patients with biopsies positive for residual tumor underwent surgical resection. There were no local or distant recurrences in treated 55 patients with a median follow up of 47 (range 36-73) months.

Conclusions: RFA can be safely used alone in patients with small breast tumors, provided that local tumor control must be regularly assessed by image-guided vacuum-assisted or core biopsies after ablation. RFA has several potential advantages over lumpectomy for the treatment of early stage breast cancer.

Citation Format: Kinoshita T, Ohtani S, Doihara H, Yamamoto N, Takahashi M, Fujisawa T, Aogi K, Hojo T, Asaga S, Yoshida M, Tsuda H. A multi-center prospective study of radiofrequency ablation therapy for small breast carcinomas [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-13-17.

Alkaline phosphatase determines polyphosphate-induced mineralization in a cell-type independent manner

Polyphosphate [Poly(P)] has positive effects on osteoblast mineralization; however, the underlying mechanism remains unclear. In addition, it is unknown whether Poly(P) promotes mineralization in soft tissues. We investigated this by using various cells. Poly(P) concentrations of 1 and 0.5 mg/mL yielded high levels of mineralization in ROS17/2.8 osteoblast cells. Similarly, Poly(P) induced mineralization in cell types expressing alkaline phosphatase (ALP), namely, ATDC5 and MC3T3-E1, but not in CHO, C3H10T1/2, C2C12, and 3T3-L1 cells. Furthermore, forced expression of ALP caused Poly(P)-induced mineralization in CHO cells. These results suggest that ALP determines Poly(P)-induced mineralization in a cell-type independent manner.

Human uterus myoma and gene expression profiling: A novel in vitro model for studying secretory leukocyte protease inhibitor-mediated tumor invasion

Secretory leukocyte protease inhibitor (SLPI) is a serine protease inhibitor that diminishes tissue destruction during inflammation. A recent report revealed high levels of SLPI expression in the oral carcinoma cell. In addition, overexpression of SLPI up-regulates metastasis in lung carcinoma cells. On the other hand, matrix metalloproteinases (MMPs) are proteinases that participate in extracellular matrix degradation. SLPI and MMPs are involved as accelerators of the tumor invasion process; however, their exact roles are not fully understood. Understanding the mechanism of tumor invasion requires models that take the effect of microenvironmental factors into account. In one such in vitro model, different carcinoma cells have been shown to invade myoma tissue in highly distinct patterns. We have used this myoma model, as it provides a more natural stroma-like environment, to investigate the role of SLPI in tumor invasion. Our results indicate that the model provides a relevant matrix for tumor invasion studies, and that SLPI is important for the invasion of oral carcinoma Ca9-22 cells in conjunction with MMPs. Furthermore, using bioinformatics analysis, we have identified candidates as key molecules involved in SLPI-mediated tumor invasion.

A Distinct Subpopulation of Bone Marrow Mesenchymal Stem Cells, Muse Cells, Directly Commit to the Replacement of Liver Components

Genotyping graft livers by short tandem repeats after human living-donor liver transplantation (n = 20) revealed the presence of recipient or chimeric genotype cases in hepatocytes (6 of 17, 35.3%), sinusoidal cells (18 of 18, 100%), cholangiocytes (15 of 17, 88.2%) and cells in the periportal areas (7 of 8, 87.5%), suggesting extrahepatic cell involvement in liver regeneration. Regarding extrahepatic origin, bone marrow mesenchymal stem cells (BM-MSCs) have been suggested to contribute to liver regeneration but compose a heterogeneous population. We focused on a more specific subpopulation (1-2% of BM-MSCs), called multilineage-differentiating stress-enduring (Muse) cells, for their ability to differentiate into liver-lineage cells and repair tissue. We generated a physical partial hepatectomy model in immunodeficient mice and injected green fluorescent protein (GFP)-labeled human BM-MSC Muse cells intravenously (n = 20). Immunohistochemistry, fluorescence in situ hybridization and species-specific polymerase chain reaction revealed that they integrated into regenerating areas and expressed liver progenitor markers during the early phase and then differentiated spontaneously into major liver components, including hepatocytes (≈74.3% of GFP-positive integrated Muse cells), cholangiocytes (≈17.7%), sinusoidal endothelial cells (≈2.0%), and Kupffer cells (≈6.0%). In contrast, the remaining cells in the BM-MSCs were not detected in the liver for up to 4 weeks. These results suggest that Muse cells are the predominant population of BM-MSCs that are capable of replacing major liver components during liver regeneration.

Chaetocin inhibits RANKL-induced osteoclast differentiation through reduction of Blimp1 in Raw264.7 cells

AIMS

Periodontitis is one of the most common bone-destructive diseases. Osteoclast is differentiated from hematopoietic macrophage-like cells through receptor activator of NFκB ligand (RANKL)-RANK signaling system, and the reduction in osteoclast formation may result in prevention of bone-resorptive diseases. Chaetocin is a compound isolated from fungal cultures and has been reported as a potent and selective inhibitor of suppressor of variegation 3-9 homolog 1 (Suv39h1), which catalyzes histone methylation on histone H3 lysine 9 (H3K9) residues. However, the effect of chaetocin on osteoclast differentiation is uncertain. In this study, we examine the effect of chaetocin on RANKL-induced osteoclast differentiation and cell growth.

MAIN METHODS

Mouse macrophage-like Raw264.7 cells were treated with RANKL in the presence or absence of chaetocin, and tartrate-resistant acid phosphatase (TRAP) staining was performed. Cell growth was measured as the amount of DNA stained with SYTOX Green dye. Expression and production of osteoclast differentiation markers, anti-osteoclastogenic genes, B lymphocyte-induced maturation protein-1 (Blimp1), and cell growth suppressors were examined by qRT-PCR or/and Western blot analysis.

KEY FINDINGS

Here we show that chaetocin dose-dependently reduced RANKL-induced osteoclast differentiation and cell growth via Blimp1 downregulation which results in the upregulation of osteoclast differentiation inhibitors and cell growth suppressors. These effects were not derived from the chaetocin's inhibitory effect of Suv39h1.

SIGNIFICANCE

These results suggest that chaetocin suppresses RANKL-induced osteoclastogenesis and cell growth through blimp1 downregulation, followed by induction of anti-osteoclastogenic genes and cell growth suppressors, without inhibition of Suv39h1. Thus, chaetocin might be a drug candidate for the prevention of bone resorption in bone-destructive diseases.

Maternal molecular hydrogen treatment attenuates lipopolysaccharide-induced rat fetal lung injury

Maternal inflammation is associated with spontaneous preterm birth and respiratory impairment among premature infants. Recently, molecular hydrogen (H2) has been reported to have a suppressive effect on oxidative stress and inflammation. The aim of this study was to evaluate the effects of H2 on fetal lung injury caused by maternal inflammation. Cell viability and the production of interleukin-6 (IL-6) and reactive oxygen species (ROS) were examined by treatment with lipopolysaccharide (LPS) contained in ordinal or H2-rich medium (HM) using a human lung epithelial cell line, A549. Pregnant Sprague Dawley rats were divided into three groups: Control, LPS, and HW + LPS groups. Rats were injected with phosphate-buffered saline (Control) or LPS intraperitoneally (LPS) on gestational day 19 and provided H2 water (HW) ad libitum for 24 h before LPS injection (HW + LPS). Fetal lung samples were collected on day 20, and the levels of apoptosis, oxidative damage, IL-6, and vascular endothelial growth factor (VEGF) were evaluated using immunohistochemistry. The number of apoptotic cells, and levels of ROS and IL-6 were significantly increased by LPS treatment, and repressed following cultured with HM in A549 cells. In the rat models, the population positive for cleaved caspase-3, 8-hydroxy-2'-deoxyguanosine, IL-6, and VEGF was significantly increased in the LPS group compared with that observed in the Control group and significantly decreased in the HW + LPS group. In this study, LPS administration induced apoptosis and oxidative damage in fetal lung cells that was ameliorated by maternal H2 intake. Antenatal H2 administration may decrease the pulmonary mobility associated with inflammation in premature infants.