Osterix and NO66 histone demethylase control the chromatin of Osterix target genes during osteoblast differentiation

Commitment of Runx2-expressing precursor osteoblasts to functional osteoblasts and then to osteocytes is triggered by Osterix (Osx), which activates its target genes in those cells during bone formation. It is not yet known whether Osx has a role in remodeling the chromatin architecture of its target genes during the transition from preosteoblast to osteoblast. In testing the hypothesis that Osx is indispensable for active chromatin architecture, we first showed that in Osx-null calvarial cells occupancy of the transcriptional activators, including lysine 4 methyl transferase (Wdr5), c-Myc, and H2A.Z, at the Osx target gene Bsp was very markedly decreased. The levels of methylation of lysines 4 and 36 and acetylation of histone H3, markers for active chromatin, were also reduced at the Bsp gene in these cells. In contrast, occupancy of the transcriptional repressors HP1 and the nucleolar protein 66 (NO66), a histone demethylase previously identified as an Osx-interacting protein, was increased at the Bsp gene in Osx-null calvarial cells. Furthermore, the Bsp promoter was hypermethylated in embryonic stem (ES) cells and in embryonic day 9.5 (E9.5) embryos but was markedly hypomethylated in the calvaria of E18.5 embryos, coinciding with robust Bsp expression. In contrast, CpG methylation in the Bsp promoter remained high in Osx-null calvaria compared to Osx-wild-type calvaria. Our data also revealed that NO66 interacted with DNA Methyltransferase 1A (DNMT1A), histone deacetylase 1A (HDAC1A), and HP1, which are known to control histone and DNA methylation. In addition, HP1 stimulated the demethylase activity of NO66 for its substrates "trimethylation of histone H3 at lysine 4" (H3K4me3) and "trimethylation of histone H3 at lysine 36" (H3K36me3). Our findings strongly suggest that in the absence of Osx, the chromatin of Osx target genes is transcriptionally inactive. We propose that Osx is a molecular switch for the formation of an active chromatin state during osteoblast differentiation, whereas NO66 helps gene repression through histone demethylation and/or formation of a repressor complex, resulting in multilayered control of the chromatin architecture of specific osteoblast genes.

E6-AP/UBE3A protein acts as a ubiquitin ligase toward SOX9 protein

SOX9 is a transcription factor that acts as a key regulator at various stages of cartilage differentiation. There is ample evidence that intracellular SOX9 protein levels are tightly regulated both by sumoylation and by degradation through the ubiquitin-proteasome pathway. Using a proteomics approach, here we report the identification of a SOX9-binding protein, E6-AP/UBE3A, that may act as a ubiquitin ligase toward Sox9. E6-AP bound SOX9 through the region consisting mostly of its high mobility group domain in vitro. In nuclear lysates, FLAG-tagged E6-AP coprecipitated with Sox9 and its high mobility group domain. This finding was estimated using nuclear lysates from a chondrocytic cell line that endogenously expresses E6-AP and SOX9. Accordingly, ectopically expressed E6-AP and SOX9 colocalized in the nucleus. We show that E6-AP ubiquitinates SOX9 in vitro and in vivo and that SOX9 levels are enhanced after addition of the proteasome inhibitor bortezomib. Similar, siRNA knockdown of E6-AP and the E2 ligase Ubc9 increased cellular SOX9 amounts, supporting the notion that SOX9 may be ubiquitinated in hypertrophic chondrocytes by E6-AP and degraded by proteasomes. This is in accordance with the distribution of SOX9 levels, which are high in proliferating and prehypertrophic chondrocytes but low in hypertrophic chondrocytes, whereas E6-AP levels are high in hypertrophic chondrocytes and low in prehypertrophic chondrocytes. Furthermore, E6-AP-deficient mice showed SOX9 accumulation in chondrocytes and the brain. These findings support the concept that E6-AP regulates SOX9 levels in developing cartilage by acting as a ubiquitin ligase.

The microtubule-associated protein astrin transgenesis rescues spermatogenesis and renal function in hypogonadic (hgn/hgn) rats

Male hypogonadic (hgn/hgn) rats show male sterility, reduced female fertility, progressive renal insufficiency and body growth retardation. These defects are associated with loss-of-function mutation of astrin and appear to be related to organ hypoplasia resulting from abnormal cell proliferation and increased cell death during embryonic and early postnatal development. As targeted disruption of mouse spag5 (astrin ortholog) has been reported to show no phenotype, we performed rescue experiments based on the introduction of rat astrin cDNA transgene into hgn/hgn rats to determine whether astrin is actually necessary for the establishment of normal male fertility and renal function. Astrin transgenic (Tg) rats were mated with hgn/+ rats of the HGN strain, and Tg-hgn/+ rats were then crossed to obtain Tg-hgn/hgn. Tg-hgn/hgn males showed recovery of body growth, fertility and renal function. Testis size was smaller in these transgenic animals than normal controls, but showed an increase by 16.5-fold compared with hgn/hgn males. Spermatogenesis occurred in Tg-hgn/hgn testes, and their accessory reproductive organs were of approximately normal size. hgn/hgn males show hypergonadotropic hypogonadism. Increased testosterone and decreased LH levels in Tg-hgn/hgn serum indicated the recovery of Leydig cells' function. Tg-hgn/hgn males showed normal reproductive behaviour, and their mating with Tg-hgn/hgn females produced pups in normal litter size. Their renal sizes and glomerular numbers showed complete recovery, and renal function assayed by biochemical parameters was normal. These results indicated that the transgene is functional in the testis and kidney development as well as body growth. In conclusion, astrin is necessary for the establishment of normal size (cell number) and function of the testis and kidney in rats.

Development of fulminant Type 1 diabetes with thrombocytopenia after influenza vaccination: a case report

BACKGROUND

Fulminant Type 1 diabetes was originally reported as idiopathic Type 1 diabetes. Involvement of viral infections in the pathogenesis of fulminant T1D has been suggested, but the development of fulminant Type 1 diabetes after influenza vaccination has not been reported.

CASE REPORT

We report a case of fulminant Type 1 diabetes with thrombocytopenia following influenza vaccination. A 54-year-old man was admitted to hospital with hyperglycaemia and diabetic ketosis. Seven days before admission, he received a seasonal influenza vaccine for the prevention of influenza infection. On admission, blood glucose was 29 mmol/L and HbA1c 40 mmol/mol (5.9%). Fasting and 2-h C-peptide immunoreactivity were <0.0333 nmol/L and 0.0999 nmol/L, respectively. Anti-GAD and anti-IA-2 antibodies were negative, so no autoimmunity seemed to participate in the etiology. ELISPOT assay also showed no association with T cell-mediated autoimmunity. HLA genotypes were consistent with susceptibility to fulminant Type 1 diabetes. After the abrupt onset of diabetes, he showed mild thrombocytopenia, which has been observed for approximately 5 years after diabetes development.

CONCLUSION

This is the first description of fulminant Type 1 diabetes after influenza vaccination. Our observation raises the possibility that influenza vaccination might trigger this condition via the TLR7 pathway.

Mineral trioxide aggregate inhibits osteoclastic bone resorption

Mineral trioxide aggregate (MTA), a commonly used endodontic repair material, is useful for both basic and clinical research, and the effect of MTA on osteoblast differentiation has been well-defined. However, the effects of MTA on osteoclastic bone resorption are not fully understood. Hence, the aim of this study is to examine the effect of MTA solution in the regulation of osteoclast bone-resorbing activity using osteoclasts formed in co-cultures of primary osteoblasts and bone marrow cells. MTA solution dose-dependently reduced the total area of pits formed by osteoclasts. The reduction of resorption induced by 20% MTA treatment was due to inhibition of osteoclastic bone-resorbing activity and had no effect on osteoclast number. A 20% MTA solution disrupted actin ring formation, a marker of osteoclastic bone resorption, by reducing phosphorylation and kinase activity of c-Src, and mRNA expressions of cathepsin K and mmp-9. A high concentration of MTA solution (50%) induced apoptosis of osteoclasts by increasing the expression of Bim, a member of the BH3-only (Bcl-2 homology) family of pro-apoptotic proteins. Taken together, our results suggest that MTA is a useful retrofilling material for several clinical situations because it both stimulates osteoblast differentiation and inhibits bone resorption.

Evaluation of serum CXCL5 as a serum marker for prognosis of colorectal cancer patients

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Background: CXCL5 is known as CXC chemokine which promotes angiogenesis related to cancer. However, the function of serum level of CXCL5 (sCXCL5) has not been fully studied in colorectal cancer. The purpose of this study was to evaluate the relationships between preoperative sCXCL5 and clinicopathological features and prognosis in colorectal cancer.

Methods: This was a single-institution, retrospective study. Preoperative serum samples of 250 colorectal cancer patients (between 1998 and 2007, median age: 65.3 years, male 159/female 91) were available for the study, and 33 normal serum was examined and used as a control. sCXCL5 level was assayed using a commercially available enzyme-linked immunosorbent assay kit, and analyzed statistically.

Results: Mean level of sCXCL5 was significantly higher in colorectal cancer patients than in control group (p=0.013). Patients with liver metastases had significantly higher sCXCL5 level than those without metastases (p=0.0086), and in logistic analysis, sCXCL5 was an independent marker for predicting liver metastasis (p=0.040). Overall survival of patients with elevated sCXCL5 level was significantly worse than those with lower sCXCL5 (p=0.0006).

Conclusions: Preoperative sCXCL5 level was increased in colorectal cancer patients compared to in healthy volunteer and elevated sCXCL5 was correlated with liver metastasis and poor prognosis for overall survival in colorectal cancer patients. Elevated sCXCL5 has been proposed as a useful predictive marker for liver metastasis and overall survival in colorectal cancer.

No significant financial relationships to disclose.

Randomized, controlled trial comparing UFT with S-1 as adjuvant therapy for curatively resected stage III colorectal cancer

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Background: Oral anticancer drug, UFT, has recently been reported to improve both overall survival (OS) and relapse-free survival (RFS) for patients with stage III colorectal cancer in Japan. We conducted a randomized clinical trial to compare S-1 with UFT for adjuvant therapy in patients with stage III colorectal cancer.

Methods: Patients with stage III colorectal cancer (PS, 0 to 1; age, 20 to 80 years) were randomized to take either UFT (400mg/m2/day, 5days per week) or S-1 (80mg/m2/day, 28days per 6weeks) for 1 year started within 6 weeks following curative resection. The primary endpoint was to investigate relations of relapse-free survival (RFS) and tissue mRNA levels of 5-FU metabolism-related enzymes. The secondary endpoint was over all survival (OS) and safety.

Results: Between July 2005 and February 2008, a total of 100 patients were registered from 21 centers. There were no clear intergroup differences in background factors. When patients who relapsed within 1 year postoperatively were excluded, the percentages of patients who took expected dosage of medicine were 73% (30/41) and 72% (33/46) in UFT and S-1 groups, respectively. Grade 3 liver dysfunction (4%) or diarrhea (4%) occurred in UFT group, whereas grade3 to 4 myelosuppression (4%), diarrhea (4%), stomatitis (2%) were observed in S-1 group, but all of them were reversible. With a median follow-up period of 1,250 days, OS in patients of UFT and S-1 groups were 86.6% and 95.9%, respectively (p=0.06). The number of patients who relapsed in rectal cancer was significantly higher in UFT group (11/25) than in S-1 group (4/21, p<0.01). In a multivariate analysis, dihydropyrimidine dehydrogenase (DPD) mRNA level was shown as a factor of the recurrences. And S-1 improved RFS in patients with rectum cancer with high orotate phosphoribosil transferase (OPRT) mRNA level.

Conclusions: Oral anticancer drug, S-1, was no less effective than UFT as an adjuvant therapy for stage III colorectal cancer. Tissue levels of both DPD and OPRT mRNA were important parameters for postoperative prognosis in patients with stage III colorectal cancer who take oral 5-FU derivatives for adjuvant therapy.

No significant financial relationships to disclose.

Use of serum CXCL16 to predict liver metastasis and prognosis in colorectal cancer patients

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Background: Colorectal cancer (CRC) is one of the major causes of cancer death worldwide. In CRC, serum levels of CEA have become well-established prognostic indicators. However, it is not generally accepted as optimal in its prognostic power. The aim of this study was to identify novel and reliable serum prognostic markers.

Methods: We performed cytokine array to identify novel prognostic serum marker, and CXCL16 was selected. To investigate the relationships between sCXCL16 and clinicopathological findings including survival, the serum levels of CXCL16 in 237 CRC patients and 20 normal volunteers were assessed by enzyme-linked immunosorbent assay. Furthermore, we investigated proliferation, invasion and wound healing assay to investigate the biological role of CXCL16 to colon cancer cell by recombinant CXCL16 exposing to HT-29.

Results: The mean sCXCL16 concentration in patients was significantly higher than that in normal volunteers (p<0.0001). In addition, sCXCL16 levels increased significantly in accordance with the progression of UICC stage classification (p < 0.05). In clinicopathologic findings, sCXCL16 was significantly associated with the presence of lymph node (p=0.019) and the presence of liver metastases (p=0.011). Elevated sCXCL16 level demonstrated a significant association with poor survival, and was an independent risk factor for poor survival. Furthermore, sCXCL16 was an independent marker for predicting liver metastasis (logistic analysis; p=0.0015). In vitro, recombinant CXCL16 promoted epithelial mesencymal transition (EMT) phenotype characterized by impaired E-cadherin and induction of Vimentin. In addition, CXCL16 promoted cell growth, migration and invasion.

Conclusions: Our data demonstrate that preoperative sCXCL16 level increased in colorectal cancer patients, and that sCXCL16 correlated with liver metastasis, and is an independent prognostic factor for overall survival. Elevated CXCL16 has been proposed as a useful predictive marker for liver metastasis and overall survival in CRC. In vitro, CXCL16/CXCR6 axis might play an importance role in mediating cell survival, migration and invasion by EMT in CRC cell.

No significant financial relationships to disclose.