PFKFB3 potentially contributes to paclitaxel resistance in breast cancer cells through TLR4 activation by stimulating lactate production

Paclitaxel is a commonly used agent for breast cancer therapy, which comes across the obstacle "drug resistance", resulting in shortened overall survival of patients. Warburg effect has become one character of cancer cell and was reported to induce paclitaxel resistance, the mechanism of which is poorly understood. In this study, we sought to examine the role of 6-Phosphofructo-2-kinase (PFKFB3), a critical regulator of glycolysis, in paclitaxel resistance development. Two clones of paclitaxel resistant breast cancer cells, MCF-7RA and MCF-7RB, were established by a long term exposure of MCF-7 cells to paclitaxel. Consequently, PFKFB3 expression was found to be increased in MCF-7RA and MCF-7RB cells compared with MCF-7 cells. Silencing PFKFB3 expression markedly reduced the IC50 concentrations of MCF-7RA and MCF-7RB cells. Moreover, PFKFB3 modulated toll like receptor 4 (TLR4) and MyD88 expression as well as interleukin (IL)-6 and IL-8 release from breast cancer cells in response to paclitaxel exposure. In addition, PFKFB3 overexpression boosted up fructose-2,6-bisphosphate (F2,6BP) and lactate production. The enhanced lactate contributed to TLR4 signaling activation, IL-6 and IL-8 generation, and cell viability promotion in MCF-7 cells. In all, we characterized the novel role of PFKFB3 in induction of paclitaxel resistance by raising lactate production and activating TLR4 signaling.

Establishment of a normal reference value of parathyroid hormone in a large healthy Chinese population and evaluation of its relation to bone turnover and bone mineral density

A normal reference value of parathyroid hormone (PTH) was established for the first time in a large sample of healthy Chinese subjects by completely excluding interference of vitamin D deficiency. A high PTH level correlated significantly with an elevated bone turnover and a reduced bone mineral density (BMD).

INTRODUCTION

The aims of this study are to establish a normal reference value for serum PTH and to evaluate the effect of parathyroid gland status on bone turnover and BMD.

METHODS

Our cross-sectional study included 1436 healthy individuals from 5 different Chinese cities. Concentrations of serum PTH, 25-hydroxyvitamin D (25OHD), procollagen I N-terminal peptide (P1NP, a bone formation marker), and carboxyl-terminal telopeptide of type I collagen (β-CTX, a bone resorption marker) were measured by electrochemiluminescence immunoassay. BMD was measured by dual-energy X-ray absorptiometry. The relation of PTH concentration to age, gender, height, and weight was examined. Reference values of PTH were established for all subjects and for subjects categorized by serum 25OHD concentrations. Correlations of PTH levels with bone turnover biomarkers and BMD were statistically analyzed.

RESULTS

Reference values of PTH were 8.84-69.95 pg/mL in all the subjects and 7.48-60.73 and 5.83-56.78 pg/mL in the subjects with serum 25OHD concentrations of ≥20 and ≥30 ng/mL, respectively. Serum PTH showed a negative linear correlation with 25OHD, and the breakpoint was 18.21 ng/mL, below which the PTH level rapidly increased. The increase in PTH levels with age showed a positive linear correlation with P1NP and β-CTX concentrations and a negative linear correlation with BMD at the lumbar spines and the femoral neck.

CONCLUSIONS

A reference value of PTH was established in a large sample of healthy Chinese subjects according to 25OHD status, gender, and age. A high PTH level correlated significantly with an elevated bone turnover and a reduced BMD.

Novel mutations of CLCN7 cause autosomal dominant osteopetrosis type II (ADO-II) and intermediate autosomal recessive osteopetrosis (IARO) in Chinese patients

SUMMARY

Osteopetrosis is a group of genetic bone disorders. Mutations in the chloride channel 7 gene (CLCN7) lead to chloride channel defect, which results in autosomal dominant osteopetrosis type II (ADO-II), autosomal recessive osteopetrosis (ARO), and intermediate autosomal recessive osteopetrosis (IARO). In the present study, we identified seven novel mutations of the CLCN7 gene and reported the first case of IARO with compound heterozygous mutation in Chinese population.

INTRODUCTION

Osteopetrosis is a heritable bone disorder due to the deficiency of or function defect in osteoclasts. Mutations in the CLCN7 lead to chloride channel defects, which result in osteopetrosis with diverse severity ranging from asymptomatic or relatively mild symptoms in ADO-II to the very severe phenotype in ARO. Heterozygous mutations in CLCN7 are associated to ADO-II, while homozygous and compound heterozygous mutations in CLCN7 may result in ARO and IARO. To date, a total of 24 mutations in CLCN7 were identified in ADO-II, and only 3 mutations were identified in IARO. In the present study, we reported seven unrelated ADO-II patients and one IARO patient from Chinese population and elucidated the characteristics of CLCN7 gene mutations in these patients.

METHODS

All 25 CLCN7 exons and exon-intron boundaries from genomic DNA were amplified and sequenced in eight affected individuals suffering from ADO-II/IARO. The clinical, biochemical, and radiographic analysis were evaluated to compare the differences between ADO-II and IARO both in genotype and phenotype.

RESULTS

The results showed that there were seven novel CLCN7 mutations identified in these ADO-II/IARO patients, including six heterozygous missense mutations (p.L224R, p.S290Y, p.R326G, p.G347R, p.S473N, and p.L564P) and a novel splice mutation (p.K691FS).

CONCLUSIONS

The compound heterozygous mutations (p.L224R and p.K691FS) were firstly observed in one IARO patient. The present study would enrich the database of CLCN7 mutations and improve our understanding of this heritable bone disorder.

Abstract P3-07-21: Non-alcoholic fatty liver disease induced by selective estrogen receptor modulators is a protective factor for breast cancer survival

Purpose: Non-alcoholic fatty liver disease (NAFLD) induced by selective estrogen receptor modulators (SERMs) treatment may be related to treatment efficacy for the antagonism of circulating estrogens. We conducted a retrospective study to investigate the relationship between survival outcomes and NAFLD in breast cancer patients treated with tamoxifen or toremifene.

Patients and methods: 785 eligible patients received tamoxifen or toremifene in Sun Yat-sen university cancer center from January 2005 to December 2009 were included in our study. All patients have at less one abdominal ultrasonography measurement at baseline and every year's follow-up. Patients who diagnosed NAFLD by ultrasonography during three-year's follow-up were classified into NAFLD cohort, others were classified into no-NAFLD cohort. Univariate and multivariate Cox regression was utilized to analyse the relationship between NAFLD and disease-free survival (DFS) and overall survival (OS).

Results:158 patients had reported NAFLD in the first 3 years' follow-up. Patients who developed NAFLD had better DFS and OS than those not developing NAFLD. The 5-years DFS was 91.56% and 85.01% at NAFLD and no-NAFLD cohort (univariate hazard ratio [HR]: 0.59 [95%CI 0.37-0.96], P=0.034), respectively. The 5-years OS was 96.64% and 93.31% at NAFLD and no-NAFLD cohort (univariate HR: 0.39 [95%CI 0.16-0.99], P=0.047), respectively. Multivariate analysis revealed that NAFLD is an independent prognostic factor on DFS in breast cancer patients with SERMs treated. Women treated with SERMs experienced NAFLD in the first three-year's follow-up had a reduced risk of DFS of 42% (multivariate HR: 0.58; [95%CI 0.36-0.95], P=0.032) compared with patients without NAFLD.

Conclusion: NAFLD induced by SERMs seems to be associated with better survival outcomes and may therefore be helpful in predicting treatment responses in breast cancer patients treated with SERMs.

Citation Format: Wang S, Zheng Q, Nie M, Xu F, Xia W, Yuan Z, Peng R, An X, Qin T, Qin G. Non-alcoholic fatty liver disease induced by selective estrogen receptor modulators is a protective factor for breast cancer survival. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-21.

The prevalence of leucocyte alloantibodies in blood donors from South China

BACKGROUND

Several studies had demonstrated that leucocyte antibodies including anti-human leucocyte antigen (anti-HLA) antibodies (class I and class II) and anti-human neutrophil antigen (anti-HNA) antibodies (HNA-1, -2 and -3) present in the blood products are responsible for transfusion-related acute lung injury (TRALI). Therefore, selection of blood products exclusive of anti-HLA and anti-HNA antibodies may lower the risk of TRALI reaction. However, the prevalence of leucocyte antibodies among blood donors in China is currently not known.

STUDY DESIGN AND METHODS

Blood samples were collected from 454 male and 560 female donors (143 nulliparous and 417 multiparous female). HLA class I and II antibodies were analyzed by bead assays. Anti-HNA-1 and -2 antibodies were screened by the LABScreen assay (One Lambda Inc.), and HNA-3 were detected by antigen capture assay, and confirmed by the granulocyte agglutination test (GAT).

RESULTS

Screening of the total cohort showed higher prevalence of HLA antibodies in female compared with male donors (19.64 vs. 4.63%). We found antibodies against HLA class I (13.21%) and HLA class II (11.43%) in 560 female donors. The most frequent antibodies against HLA class I and II in parous females (n = 69) reacted with were A*11 (28.81%), B*07 (42.37%), Cw*07 (20.34%) and DRB1*04 (40.43%) molecules. Among 778 donors (randomly selected from 1014 donors), we found three donors with neutrophil reactive antibodies, two against HNA-2 and one without known specificity. Anti-HNA-3 antibodies were not found so far.

CONCLUSION

In this study, we found alloimmunization against HLA class I, II and HNA in 4.63, 24.70 and 0.39%, respectively, in our female blood donors, indicating that the use of plasma containing blood products from parous female blood donors without HLA antibodies pre-testing may increase the risk of TRALI reaction. Although immunization against HNA seems to be a rare event in China, further observation is necessary to decide the necessity of HNA antibodies screening in our blood donors.

Analysis of genetic diversity and population structure of oil palm (Elaeis guineensis) from China and Malaysia based on species-specific simple sequence repeat markers

Genetic diversity and patterns of population structure of the 94 oil palm lines were investigated using species-specific simple sequence repeat (SSR) markers. We designed primers for 63 SSR loci based on their flanking sequences and conducted amplification in 94 oil palm DNA samples. The amplification result showed that a relatively high level of genetic diversity was observed between oil palm individuals according a set of 21 polymorphic microsatellite loci. The observed heterozygosity (Ho) was 0.3683 and 0.4035, with an average of 0.3859. The Ho value was a reliable determinant of the discriminatory power of the SSR primer combinations. The principal component analysis and unweighted pair-group method with arithmetic averaging cluster analysis showed the 94 oil palm lines were grouped into one cluster. These results demonstrated that the oil palm in Hainan Province of China and the germplasm introduced from Malaysia may be from the same source. The SSR protocol was effective and reliable for assessing the genetic diversity of oil palm. Knowledge of the genetic diversity and population structure will be crucial for establishing appropriate management stocks for this species.

The rs5934505 single nucleotide polymorphism (SNP) is associated with low testosterone and late-onset hypogonadism, but the rs10822184 SNP is associated with overweight and obesity in a Chinese Han population: a case-control study

Low testosterone is associated with late-onset hypogonadism (LOH) and obesity. Recently, studies have shown that four single nucleotide polymorphisms (SNPs), rs12150660, rs727428, rs5934505, and rs10822184, are associated with testosterone levels in populations of European descent. Therefore, we investigated whether the SNP loci are related to low testosterone, LOH, or obesity in a Chinese Han population. Ruling out co-morbidities, DNA was prepared from 409 men (aged 40-65 years) with low serum testosterone (defined as total testosterone <11.6 nmol/L) and 1 : 1 normal controls (matched age, body mass index (BMI), and the same living area) who were selected from 6898 males. According to the same standards, 310 men with LOH and 1 : 1 normal controls were selected from 6898 males. Excluding the cases with an unreliable sequencing result, genetic analyses were performed. The minor allele frequencies of the SNP loci rs12150660, rs727428, rs5934505, and rs10822184 were 0.1%, 44.6%, 18.7%, and 38.9%, respectively. rs5934505 was associated with the serum total testosterone and calculated free testosterone (CFT) levels (p = 0.045 and p = 0.021). rs5934505 (C>T) was associated with an increased risk of low total testosterone, low CFT, and LOH and adjusted for other factors, with an odds ratio (OR) of 2.01 (1.34-3.01), 2.14 (1.42-3.20), and 1.64 (1.04-2.58). rs10822184 was significantly correlated with weight and BMI (p = 0.035 and p = 0.027). rs10822184 (T>C) was associated with an increased risk of overweight and obesity. We adjusted for other factors, with odds ratios (ORs) of 1.94 (1.36-2.78) and 1.56 (1.00-2.43). In summary, our study provided convincing evidence that rs5934505 (C>T) was associated with the risk of low testosterone and LOH in Chinese populations. We were the first to find that rs10822184 (T>C) was significantly correlated with the risk of overweight and obesity in Chinese populations. However, further large and functional studies are warranted to confirm our findings.

A survey of outcomes and management of patients post fragility fractures in China

We found that the fragility hip and vertebral fractures caused excess mortality rates in this Chinese female population, which was unexpectedly lower than those in western countries and other Asian countries. This was the first nationwide survey relating to post-fracture outcomes conducted among Chinese population in Mainland China.

INTRODUCTION

This study aimed to investigate the mortality, self-care ability, diagnosis, and medication treatment of osteoporosis following fragility hip and vertebral fractures through a nationwide survey among female patients aged over 50 in Mainland China.

METHODS

This was a multicenter, retrospective cohort study based on medical chart review and patient questionnaire. Female patients aged 50 or older admitted for low-trauma hip or vertebral fractures and discharged from Jan 1, 2008 to Dec 31, 2012 were followed.

RESULTS

Total of 1151 subjects of hip fracture and 842 subjects of vertebral fracture were included. The mean age was 73.4 ± 10.0, and the median of duration from index fracture to interview was 2.6 years. The overall 1-year, 2-year, 3-year, 4-year, and 5-year cumulative mortality rates were 3.5, 7.0, 11.2, 13.1, and 16.9 %, respectively. The first year mortality rates in hip (3.8 %, 95% CI 3.3-4.4 %) and vertebral fracture (3.1 %, 95% CI 2.5-3.7 %) were significantly higher than that in the general population (1.6 %). Impaired self-care ability was observed in 33.2, 40.6, and 23.8 % of overall, hip fracture, and vertebral fracture group, respectively. The overall diagnosis rate of osteoporosis was 56.8 %, and bone mineral density (BMD) measurement had never been conducted in 42.0 % among these women. After the index fracture, 69.6 % of them received supplements and/or anti-osteoporotic medications, among which 39.6 % only received calcium with/without vitamin D supplementation.

CONCLUSIONS

The osteoporotic hip and vertebral fractures caused excess mortality rates in this population of Mainland China. The current diagnosis and medical treatment following the fragility fractures is still insufficient in Mainland China.

Interferon-α-2b as an adjuvant therapy prolongs survival of patients with previously resected oral muscosal melanoma

Two major subtypes of melanoma include cutaneous melanoma and mucosal melanoma. The latter type is rare and usually occurs in the head and neck region. High-dose interferon-α-2b (IFN-α-2b) has proven effective in the treatment of cutaneous melanoma. Recently, a regimen of temozolomide plus cisplatin was reported more likely to improve relapse-free survival and overall survival than high-dose IFN-α-2b for mucosal melanoma. We conducted this study to analyze the therapeutic effect of high-dose IFN-α-2b for patients with oral mucosal melanoma who had received prior chemotherapy. One hundred and seventeen patients with stage III-IVa oral mucosal melanoma who had received chemotherapy were analyzed. The overall survival and relapse-free survival were compared between the patients with/without high-dose IFN-α-2b. The results indicate that the IFN-α-2b treatment group had a longer relapse-free survival rate (P = 0.0169) as compared to the control group. However, the overall survival was not significant between the two groups (P = 0.096), except in patients in stage IVa, whose overall survival increased by 20 months (P = 0.0146). The adverse reactions included a drug-induced influenza-like syndrome, gastrointestinal responses, myelosuppression, and hepatoxicity, which were predominantly of grade 1-2 and reversible. Thus, patients with resected oral mucosal melanoma, even those who have received chemotherapy, could benefit from the treatment of high-dose IFN-α-2b.

Conversion, shrinkage, water sorption, flexural strength and modulus of re-mineralizing dental composites

OBJECTIVES

Cure, volumetric changes and mechanical properties were assessed for new dental composites containing chlorhexidine (CHX) and reactive calcium phosphate-containing (CaP) to reduce recurrent caries.

METHODS

20wt.% of light curable urethane dimethacrylate based liquid was mixed with 80wt.% glass filler containing 10wt.% CHX and 0-40wt.% CaP. Conversion versus depth with 20 or 40s light exposure was assessed by FTIR. Solidification depth and polymerization shrinkage were determined using ISO 4049 and 17304, respectively. Subsequent volume expansion and biaxial flexural strength and modulus change upon water immersion were determined over 4 weeks. Hydroxyapatite precipitation in simulated body fluid was assessed at 1 week.

RESULTS

Conversion decreased linearly with both depth and CaP content. Average solidification depths were 4.5, 3.9, 3.3, 2.9 and 5.0 with 0, 10, 20, and 40% CaP and a commercial composite, Z250, respectively. Conversions at these depths were 53±2% for experimental materials but with Z250 only 32%. With Z250 more than 50% conversion was achieved only below 1.1mm. Shrinkage was 3% and 2.5% for experimental materials and Z250, respectively. Early water sorption increased linearly, whilst strength and modulus decreased exponentially to final values when plotted versus square root of time. Maximum volumetric expansion increased linearly with CaP rise and balanced shrinkage at 10-20wt.% CaP. Strength and modulus for Z250 decreased from 191 to 158MPa and 3.2 to 2.5GPa. Experimental composites initial strength and modulus decreased linearly from 169 to 139MPa and 5.8 to 3.8GPa with increasing CaP. Extrapolated final values decreased from 156 to 84MPa and 4.1 to 1.7GPa. All materials containing CaP promoted hydroxyapatite precipitation.

SIGNIFICANCE

The lower surface of composite restorations should both be solid and have greater than 50% conversion. The results, therefore, suggest the experimental composite may be placed in much thicker layers than Z250 and have reduced unbounded cytotoxic monomer. Experimental materials with 10-20wt.% additionally have volumetric expansion to compensate shrinkage, antibacterial and re-mineralizing components and competitive mechanical properties.

A novel lncRNA, LUADT1, promotes lung adenocarcinoma proliferation via the epigenetic suppression of p27

Long noncoding RNAs (lncRNAs) are known to regulate the development and progression of various cancers. However, few lncRNAs have been well characterized in lung adenocarcinoma (LUAD). Here, we identified the expression profile of lncRNAs and protein-coding genes via microarrays analysis of paired LUAD tissues and adjacent non-tumor tissues from five female non-smokes with LUAD. A total of 498 lncRNAs and 1691 protein-coding genes were differentially expressed between LUAD tissues and paired adjacent normal tissues. A novel lncRNA, LUAD transcript 1 (LUADT1), which is highly expressed in LUAD and correlates with T stage, was characterized. Both in vitro and in vivo data showed that LUADT1 knockdown significantly inhibited proliferation of LUAD cells and induced cell cycle arrest at the G0–G1 phase. Further analysis indicated that LUADT1 may regulate cell cycle progression by epigenetically inhibiting the expression of p27. RNA immunoprecipitation and chromatin immunoprecipitation assays confirmed that LUADT1 binds to SUZ12, a core component of polycomb repressive complex 2, and mediates the trimethylation of H3K27 at the promoter region of p27. The negative correlation between LUADT1 and p27 expression was confirmed in LUAD tissue samples. These data suggested that a set of lncRNAs and protein-coding genes were differentially expressed in LUAD. LUADT1 is an oncogenic lncRNA that regulates LUAD progression, suggesting that dysregulated lncRNAs may serve as key regulatory factors in LUAD progression.

Suppressed bone turnover was associated with increased osteoporotic fracture risks in non-obese postmenopausal Chinese women with type 2 diabetes mellitus

We found that type 2 diabetes mellitus (T2DM) was associated with increased fracture risks in non-obese postmenopausal Chinese women, and suppressed bone turnover might be the underlying mechanism. This is the first study evaluating and explaining the association of T2DM with osteoporotic fracture in Chinese population with such high homogeneity.

INTRODUCTION

The aim of this study was to investigate the association of T2DM with osteoporotic fracture in postmenopausal Chinese women.

METHODS

One thousand four hundred ten postmenopausal women were included and stratified into non-obese population [body mass index (BMI) < 25 kg/m(2)] and obese population (BMI ≥ 25 kg/m(2)). Each type of population was classified into diabetes group, impaired fasting glucose (IFG) group, and normal glucose group. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry. Serum C-terminal telopeptide of type I collagen (β-CTX) and serum N-amino terminal prepeptide of type 1 procollagen (P1NP) were quantified. Vertebral fractures (VFs) and non-VFs were assessed by vertebral X-ray and questionnaire, respectively.

RESULTS

Comparing to normal glucose group, diabetes group and IFG group both had lower levels of P1NP and β-CTX, despite population types. Despite having non-decreased BMD, non-obese diabetic patients had higher risks of total fracture and VF than BMI-matched normal glucose subjects (both P < 0.05). Non-obese population was further classified by a mean value of P1NP or β-CTX. Non-obese diabetic patients with low P1NP or high β-CTX had higher fracture risks (both P < 0.05), comparing to non-obese normal glucose subjects with high P1NP or high β-CTX, respectively.

CONCLUSIONS

Type 2 diabetic patients had suppressed bone turnover, which might explain the increased fracture risks, independent of BMD. IFG patients might also have poor bone quality and need early prevention.

Genesis of the novel human-infecting influenza A(H10N8) virus and potential genetic diversity of the virus in poultry, China

Human infection with a novel influenza A(H10N8) virus was first described in China in December 2013. However, the origin and genetic diversity of this virus is still poorly understood. We performed a phylogenetic analysis and coalescent analysis of two viruses from the first case of influenza A(H10N8) (A/Jiangxi-Donghu/346-1/2013 and A/Jiangxi-Donghu/346-2/2013 and a novel A(H10N8) virus (A/chicken/Jiangxi/102/2013) isolated from a live poultry market that the patient had visited. The haemagglutinin (HA), neuraminidase (NA), PA subunit of the virus polymerase complex, nucleoprotein (NP), M and nonstructural protein (NS) genes of the three virus strains shared the same genetic origins. The origins of their HA and NA genes were similar: originally from wild birds to ducks, and then to chickens. The PA, NP, M, and NS genes were similar to those of chicken influenza A(H9N2) viruses. Coalescent analyses showed that the reassortment of these genes from A(H9N2) to A(H10N8) might have occurred at least twice. However, the PB1 and PB2 genes of the chicken A(H10N8) virus most likely originated from H7-like viruses of ducks, while those of the viruses from the case most likely stemmed from A(H9N2) viruses circulating in chickens. The oseltamivir-resistance mutation, R292K (R291K in A(H10N8) numbering) in the NA protein, occurred after four days of oseltamivir treatment. It seems that A(H10N8) viruses might have become established among poultry and their genetic diversity might be much higher than what we have observed.

Slc26a3 deficiency is associated with loss of colonic HCO3 (-) secretion, absence of a firm mucus layer and barrier impairment in mice

AIM

Downregulated in adenoma (DRA, Slc26a3) is a member of the solute carrier family 26 (SLC26), family of anion transporters, which is mutated in familial chloride-losing diarrhoea (CLD). Besides Cl(-) -rich diarrhoea, CLD patients also have a higher-than-average incidence of intestinal inflammation. In a search for potential explanations for this clinical finding, we investigated colonic electrolyte transport, the mucus layer and susceptibility against dextran sodium sulphate (DSS)-induced colitis in Slc26a3(-/-) mice.

METHODS

HCO3 (-) secretory (JHCO3 (-) ) and fluid absorptive rates were measured by single-pass perfusion in vivo and in isolated mid-distal colonic mucosa in Ussing chambers in vitro. Colonocyte intracellular pH (pHi ) was assessed fluorometrically, the mucus layer by immunohistochemistry and colitis susceptibility by the addition of DSS to the drinking water.

RESULTS

HCO3 (-) secretory (JHCO3- ) and fluid absorptive rates were strongly reduced in Slc26a3(-/-) mice compared to wild-type (WT) littermates. Despite an increase in sodium/hydrogen exchanger 3 (NHE3) mRNA and protein expression, and intact acid-activation of NHE3, the high colonocyte pH in Slc26a3(-/-) mice prevented Na(+) /H(+) exchange-mediated fluid absorption in vivo. Mucin 2 (MUC2) immunohistochemistry revealed the absence of a firm mucus layer, implying that alkaline secretion and/or an absorptive flux may be necessary for optimal mucus gel formation. Slc26a3(-/-) mice were highly susceptible to DSS damage.

CONCLUSIONS

Deletion of DRA results in severely reduced colonic HCO3 (-) secretory rate, a loss of colonic fluid absorption, a lack of a firmly adherent mucus layer and a severely reduced colonic mucosal resistance to DSS damage. These data provide potential pathophysiological explanations for the increased susceptibility of CLD patients to intestinal inflammation.

Hydroxyapatite coating affects the Wnt signaling pathway during peri-implant healing in vivo

Owing to its bio- and osteoconductivity, hydroxyapatite (HA) is a widely used implant material, but its osteogenic properties are only partly evaluated in vitro and in vivo. The present study focused on bone healing adjacent to HA-coated titanium (Ti) implants, with or without incorporated lithium ions (Li(+)). Special attention was given to the Wnt signaling pathway. The implants were inserted into rat tibia for 7 or 28 days and analyzed ex vivo, mainly by histomorphometry and quantitative real-time polymerase chain reaction (qPCR). HA-coated implants showed, irrespective of Li(+) content, bone-implant contact (BIC) and removal torque values significantly higher than those of reference Ti. Further, the expression of OCN, CTSK, COL1A1, LRP5/6 and WISP1 was significantly higher in implant-adherent cells of HA-coated implants, with or without Li(+). Significantly higher β-catenin expression and significantly lower COL2A1 expression were observed in peri-implant bone cells from HA with 14 ng cm(-2) released Li(+). Interestingly, Ti implants showed a significantly larger bone area (BA) in the threads than HA with 39 ng cm(-2) released Li(+), but had a lower BIC than any HA-coated implant. This study shows that HA, with or without Li(+), is a strong activator of the Wnt signaling pathway, and may to some degree explain its high bone induction capacity.

Quantifying effects of interactions between polyacrylic acid and chlorhexidine in dicalcium phosphate – forming cements

Polyacrylic acid has been shown to control setting and improve mechanical and antibacterial release properties of brushite bone cements.

Adrenomedullin and adrenotensin regulate collagen synthesis and proliferation in pulmonary arterial smooth muscle cells

To understand the pathophysiological mechanisms of pulmonary arterial smooth muscle cell (PASMC) proliferation and extracellular-matrix accumulation in the development of pulmonary hypertension and remodeling, this study determined the effects of different doses of adrenomedullin (ADM) and adrenotensin (ADT) on PASMC proliferation and collagen synthesis. The objective was to investigate whether extracellular signal-regulated kinase (ERK1/2) signaling was involved in ADM- and ADT-stimulated proliferation of PASMCs in 4-week-old male Wistar rats (body weight: 100-150 g, n=10). The proliferation of PASMCs was examined by 5-bromo-2-deoxyuridine incorporation. A cell growth curve was generated by the Cell Counting Kit-8 method. Expression of collagen I, collagen III, and phosphorylated ERK1/2 (p-ERK1/2) was evaluated by immunofluorescence. The effects of different concentrations of ADM and ADT on collagen I, collagen III, and p-ERK1/2 protein expression were determined by immunoblotting. We also investigated the effect of PD98059 inhibition on the expression of p-ERK1/2 protein by immunoblotting. ADM dose-dependently decreased cell proliferation, whereas ADT dose-dependently increased it; and ADM and ADT inhibited each other with respect to their effects on the proliferation of PASMCs. Consistent with these results, the expression of collagen I, collagen III, and p-ERK1/2 in rat PASMCs decreased after exposure to ADM but was upregulated after exposure to ADT. PD98059 significantly inhibited the downregulation by ADM and the upregulation by ADT of p-ERK1/2 expression. We conclude that ADM inhibited, and ADT stimulated, ERK1/2 signaling in rat PASMCs to regulate cell proliferation and collagen expression.

Hepatic DNA methylation modifications in early development of rats resulting from perinatal BPA exposure contribute to insulin resistance in adulthood

AIMS/HYPOTHESIS

Perinatal exposure to bisphenol A (BPA), a widely distributed environmental endocrine disruptor, is associated with insulin resistance and diabetes in offspring. The underlying molecular mechanisms could involve epigenetics, as adverse effects induced by environmental exposure in early life are suggested through DNA methylation. In this study we sought to elucidate the relationship between perinatal BPA exposure and alteration of hepatic DNA methylation.

METHODS

Pregnant Wistar rats were administered BPA (50 μg/kg/day) or corn oil by oral gavage throughout gestation and lactation. Variables associated with insulin resistance and hepatic DNA methylation were examined at postnatal week 3 and week 21 in male offspring.

RESULTS

In BPA-treated offspring, serum insulin and HOMA-insulin resistance were increased, and the insulin sensitivity index and hepatic glycogen storage were decreased compared with controls at week 21. At week 3, none of these variables were significantly changed. However, hepatic global DNA methylation was decreased, accompanied by overexpression of DNA methyltransferase 3B mRNA at week 3. Meanwhile, perinatal exposure to BPA induced promoter hypermethylation and a reduction in gene expression of hepatic glucokinase. Moreover, increased promoter hypermethylation of Gck became more pronounced in BPA-treated offspring at week 21.

CONCLUSIONS/INTERPRETATION

Abnormal DNA methylation in hepatic tissue precedes development of insulin resistance induced by perinatal BPA exposure. These findings support the potential role of epigenetics in fetal reprogramming by BPA-induced metabolic disorders.