Identification and characterization of the novel Col10a1 regulatory mechanism during chondrocyte hypertrophic differentiation

The majority of human skeleton develops through the endochondral pathway, in which cartilage-forming chondrocytes proliferate and enlarge into hypertrophic chondrocytes that eventually undergo apoptosis and are replaced by bone. Although at a terminal differentiation stage, hypertrophic chondrocytes have been implicated as the principal engine of bone growth. Abnormal chondrocyte hypertrophy has been seen in many skeletal dysplasia and osteoarthritis. Meanwhile, as a specific marker of hypertrophic chondrocytes, the type X collagen gene (COL10A1) is also critical for endochondral bone formation, as mutation and altered COL10A1 expression are often accompanied by abnormal chondrocyte hypertrophy in many skeletal diseases. However, how the type X collagen gene is regulated during chondrocyte hypertrophy has not been fully elucidated. We have recently demonstrated that Runx2 interaction with a 150-bp mouse Col10a1 cis-enhancer is required but not sufficient for its hypertrophic chondrocyte-specific reporter expression in transgenic mice, suggesting requirement of additional Col10a1 regulators. In this study, we report in silico sequence analysis of this 150-bp enhancer and identification of its multiple binding factors, including AP1, MEF2, NFAT, Runx1 and TBX5. Using this enhancer as bait, we performed yeast one-hybrid assay and identified multiple candidate Col10a1-interacting genes, including cyclooxygenase 1 (Cox-1) and Cox-2. We have also performed mass spectrometry analysis and detected EF1-alpha, Fus, GdF7 and Runx3 as components of the specific complex formed by the cis-enhancer and nuclear extracts from hypertrophic MCT (mouse chondrocytes immortalized with large T antigen) cells that express Col10a1 abundantly. Notably, some of the candidate genes are differentially expressed in hypertrophic MCT cells and have been associated with chondrocyte hypertrophy and Runx2, an indispensible Col10a1 regulator. Intriguingly, we detected high-level Cox-2 expression in hypertrophic MCT cells. Electrophoretic mobility shift assay and chromatin immunoprecipitation assays confirmed the interaction between Cox-2 and Col10a1 cis-enhancer, supporting its role as a candidate Col10a1 regulator. Together, our data support a Cox-2-containing, Runx2-centered Col10a1 regulatory mechanism, during chondrocyte hypertrophic differentiation.

ABCB1 polymorphisms predict imatinib response in chronic myeloid leukemia patients: a systematic review and meta-analysis

Imatinib mesylate, a competitive tyrosine kinase inhibitor, is considered the first-line therapy drug for Ph+ chronic myeloid leukemia (CML). Three single-nucleotide polymorphisms (SNPs) in the ATP-binding cassette, subfamily B (MDR/TAP), member 1 gene (ABCB1/MDR1), c.1236C>T, c.2677G>T/A and c.3435C>T, have been shown to affect cellular transport/metabolism of imatinib. The associations between these SNPs and imatinib response in CML patients have been widely evaluated, but the results were inconsistent. To derive a conclusive assessment of the associations, we performed a meta-analysis by combining data from a total of 12 reports including 1826 patients. The results showed that the 2677G allele or 3435T allele predicted a worse response to imatinib in CML patients, whereas 1236CC genotype was associated with better response in CML patients from Asian region. In conclusion, this meta-analysis suggests that c.1236C>T, c.2677G>T/A and c.3435C>T can be served as predictive markers for the therapeutical use of imatinib in CML patients.

Measurement of a MMP-2 degraded Titin fragment in serum reflects changes in muscle turnover induced by atrophy

PURPOSE

In this study we sought to determine whether a Titin peptide fragment can serve as a clinical biomarker for changes in muscle mass.

METHODS

Mass spectrometry was used to identify Titin fragment in urine. An antibody against this Titin sequence was raised and used to develop a competitive ELISA assay for measurement in serum. Rat tissue extractions in the presence or absence of a series of proteases of interest were used to identify its enzymatic origin. A rat model of dexamethasone (DEX) induced muscle atrophy and a human 56-day bed rest study with and without vibration therapy were used to assess biological and clinical relevance.

RESULTS

A technically robust ELISA measuring the Titin fragment was developed against a Titin peptide fragment identified in human urine. The fragment was shown to be produced primarily by MMP-2 cleavage of Titin. In the rat muscle DEX induced atrophy model, Titin-MMP2 fragment was decreased in the beginning of DEX treatment, and then significantly increased later on during DEX administration. In the human bed rest study, the Titin-MMP2 fragment was initially decreased 11.9 (±3.7) % after 1day of bed rest, and then gradually increased ending up at a 16.4 (±4.6) % increase at day 47.

CONCLUSIONS

We developed a robust ELISA measuring a muscle derived MMP-2 generated Titin degradation fragment in rat and human serum. Importantly, the fragment can be measured in serum and that these levels are related to induction of skeletal muscle atrophy.

Investigating conversion of endplate chondrocytes induced by intermittent cyclic mechanical unconfined compression in three-dimensional cultures

Mechanical stimulation is known to regulate the calcification of endplate chondrocytes. The Ank protein has a strong influence on anti-calcification by transports intracellular inorganic pyrophosphate (PPi) to the extracellular matrix. It is known that TGF-β1 is able to induce Ank gene expression and protect chondrocyte calcification. Intermittent cyclic mechanical tension (ICMT) could induce calcification of endplate chondrocytes by decrease the expression of Ank gene. In this study, we investigated the relation of intermittent cyclic mechanical unconfined compression (ICMC) and Ank gene expression. We found that ICMC decreased the Ank gene expression in the endplate chondrocytes, and there was an decreased in the TGF-β1 expression after ICMC stimulation. The Ank gene expression significantly increased when treated by transforming growth factor alpha 1 (TGF-β1) in a dose-dependent manner and decreased when treated by SB431542 (ALK inhibitor) in a dose-dependent manner. Our results implicate that ICMC-induced downregulation of Ank gene expression may be regulated by TGF-β1 in end-plate chondrocytes.

Development of an improved RT-LAMP assay for detection of currently circulating rubella viruses

Rubella virus is the causative agent of rubella. The symptoms are usually mild, and characterized by a maculopapular rash and fever. However, rubella infection in pregnant women sometimes can result in the birth of infants with congenital rubella syndrome (CRS). Global efforts have been made to reduce and eliminate CRS. Although a reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay for detection of rubella virus has been reported, the primers contained several mismatched nucleotides with the genomes of currently circulating rubella virus strains. In the present study, a new RT-LAMP assay was established. The detection limit of this assay was 100-1000PFU/reaction of viruses for all rubella genotypes, except for genotype 2C, which is not commonly found in the current era. Therefore, the new RT-LAMP assay can successfully detect all current rubella virus genotypes, and does not require sophisticated devices like TaqMan real-time PCR systems. This assay should be a useful assay for laboratory diagnosis of rubella and CRS.

Effects of 24-epibrassinolide on plant growth, osmotic regulation and ion homeostasis of salt-stressed canola

This study evaluated effects of foliar spraying 24-epibrassinoide (24-EBL) on the growth of salt-stressed canola. Seedlings at the four-leaf stage were treated with 150 mM NaCl and different concentrations of 24-EBL (10(-6), 10(-8), 10(-10), 10(-12) M) for 15 days. A concentration of 10(-10) M 24-EBL was chosen as optimal and used in a subsequent experiment on plant biomass and leaf water potential parameters. The results showed that 24-EBL mainly promoted shoot growth of salt-stressed plants and also ameliorated leaf water status. Foliar spraying of salt-stressed canola with 24-EBL increased osmotic adjustment ability in all organs, especially in younger leaves and roots. This was mainly due to an increase of free amino acid content in upper leaves, soluble sugars in middle leaves, organic acids and proline in lower leaves, all of these compounds in roots, as well as essential inorganic ions. Na(+) and Cl(-) sharply increased in different organs under salt stress, and 24-EBL reduced their accumulation. 24-EBL improved the uptake of K(+), Ca(2+), Mg(2+) and NO3(-) in roots, which were mainly transported to upper leaves, while NO3(-) was mainly transported to middle leaves. Thus, 24-EBL improvements in ion homeostasis of K(+)/Na(+), Ca(2+)/Na(+), Mg(2+)/Na(+) and NO3(-)/Cl(-), especially in younger leaves and roots, could be explained. As most important parts, younger leaves and roots were the main organs protected by 24-EBL via improvement in osmotic adjustment ability and ion homeostasis. Further, physiological status of growth of salt-stressed canola was ameliorated after 24-EBL treatment.

Associations between physical activity-related miRNAs and metabolic syndrome

The aim of the study was to investigate the associations between physical activity (PA)-related miRNAs and metabolic syndrome (MetS). A case-control study was conducted in 209 subjects with MetS and 234 controls. The MetS was defined by the International Diabetes Foundation (IDF) criteria of 2005. Serum PA-related miRNAs were detected by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) assays. Association analysis was performed by logistic regression models. The expression levels of miR-126 and miR-130a were lower in the highest metabolic equivalent hours per week (MET-h/week) quartile than in the lowest quartile [miR-126: Q5 vs. Q1, median (5-95%), 1.67 (0.54, 2.45) vs. 1.35 (0.45, 2.45), p=0.012; miR-130a: Q5 vs. Q1, median (5-95%), 0.90 (0.44, 1.35) vs. 0.53 (0.26, 1.01), p<0.001]. However, miR-197 exhibited a trend with increased MET-h/week [Q5 vs. Q1, median (5-95%), 1.35 (0.45, 2.63) vs. 2.18 (0.87, 4.77), p=0.009]. MiR-126 increased MetS risk significantly while the effect of miR-197 was opposite (miR-126: OR=1.37, 95% CI 1.07-1.75; p=0.012; miR-197: OR=0.68, 95% CI 0.51-0.92; p=0.010). Individuals in the highest MET-h/week quartile had lower prevalence and odds rate of MetS compared with those in the lowest quartile (Q4 vs. Q1: OR=0.58, 95% CI 0.33-1.05; p for trend=0.026). However, further adjustment of both PA associated miRNAs abolished that association. All these results suggested that the association between PA and MetS risk might partly depend on miR-126 and miR-197.

Synergistic Effect of Regeneration and Inflammation via Ibuprofen-Loaded Electrospun Fibrous Scaffolds for Repairing Skeletal Muscle

Adult skeletal muscle regeneration involves serial steps among which inflammation in the wounded area is critical for the healing process. However, accelerated tissue regeneration and the inhibition of excessive inflammation are always the targets of tissue engineering, because excessive inflammation in the early stage can impede the regeneration in the following step. In this study, a feasible ibuprofen-loaded poly (L-lactide) (PLLA) fibrous scaffold was designed to evaluate the ability of preventing excessive inflammatory response and promoting regeneration using 35 Sprague-Dawley (SD) rats. The cytotoxicity assay of PLLA and ibuprofen-loaded PLLA fibrous scaffolds (IBU/PLLA) showed that there were no significant cell cytotoxicity on L6 cells. The histological results showed that the IBU/PLLA group had slighter inflammation than PLLA and control groups during the whole process. In the later stage, the regeneration process of the IBU/PLLA group took place on the 7th day, which was almost more than one week earlier than the PLLA and control groups. qRT-PCR analysis further displayed that the IBU/PLLA group had a lower level of inflammatory factors and higher expression of repair factors than the PLLA and control groups, especially from the 7th day, and lasted until the 21st day. Furthermore, there were no statistical differences between the PLLA group and the control group from histological results and qRT-PCR analysis. Taken together, through the muscle wound healing process, the results demonstrated that the ibuprofen-loaded PLLA fibrous scaffolds had better control of excessive inflammation and faster process of healing than non-ibuprofen-loaded groups.

Cystic fibrosis transmembrane conductance regulator is correlated closely with sperm progressive motility and normal morphology in healthy and fertile men with normal sperm parameters

Cystic fibrosis transmembrane conductance regulator (CFTR) has been demonstrated to be expressed in mature spermatozoa and correlated with sperm quality. Sperm CFTR expression in fertile men is higher than that in infertile men suffering from teratospermia, asthenoteratospermia, asthenospermia and oligospermia, but it is unknown whether CFTR is correlated with sperm parameters when sperm parameters are normal. In this study, 282 healthy and fertile men with normal semen parameters were classified into three age groups, group (I): age group of 20-29 years (98 cases, 27.1 ± 6.2), group (II): age group of 30-39 years (142 cases, 33.7 ± 2.6) and group (III): age group of more than or equal to 40 years (42 cases, 44.1 ± 4.6). Sperm concentration, total count and progressive motility were analysed by computer-assisted sperm analysis. Sperm morphology was analysed by modified Papanicolaou staining. Sperm CFTR expression was conducted by indirect immunofluorescence staining. There was a significant positive correlation (P < 0.001) between CFTR expression and sperm progressive motility (r = 0.221) and normal morphology (r = 0.202), but there were no correlations between sperm CFTR expression and semen volume, sperm concentration, sperm total count as well as male age (P > 0.05). Our findings show that CFTR expression is associated with sperm progressive motility and normal morphology in healthy and fertile men with normal sperm parameters, but not associated with the number of spermatozoa and male age.

Pioglitazone, extract of compound Danshen dripping pill, and quercetin ameliorate diabetic nephropathy in diabetic rats

BACKGROUND

Oxidative stress appears to play a role in the pathogenesis of diabetes mellitus (DM), and disruption of the ubiquitin-proteasome system may underlie these pathological changes. We tested the effect of pioglitazone (PIO), an extract of Danshen dripping pill (DSP), and quercetin (QUE) on the pathogenesis of DM in a rat model.

METHODS

Male Sprague Dawley rats were maintained in a normal control (NC) group or given a modified diet and streptozotocin (STZ) to induce DM. After STZ treatment, rats were given intragastric placebo, PIO, DSP, or QUE for 8 weeks. At the end of the treatment period, serum and urine chemistry, renal hypertrophy, renal histopathology, and renal expression of ubiquitin and nuclear factor (NF)-κB p65 were analyzed.

RESULTS

DM rats had altered body and kidney weight, altered serum and urine chemistry, increased accumulation of glomerular extracellular matrix (ECM), and increased renal expression of ubiquitin and NF-κB p65, indicating successful establishment of our DM model. Treatment with PIO, DSP, or QUE significantly ameliorated these pathological changes, although treated rats still had some symptoms of DM.

CONCLUSION

DM rats have increased expression of ubiquitin and NF-κB p65 in their renal tubules and glomeruli. PIO, DSP, and QUE ameliorated the pathological changes associated with DM and also reduced the renal expression of ubiquitin and NF-κB p65. These agents may provide protection from renal pathology associated with DM due to their anti-oxidant effects.

A meta-analysis of the relationship between lymphatic microvessel density and the survival of patient with colorectal cancer

Colorectal cancer (CRC) is a frequently observed malignant neoplasm that is a leading cause of cancer death despite recent advances in treatment and research. The role of lymphangiogenesis in CRC development is a source of controversy in current research. We undertook this study to examine the relationship between lymphatic microvessel density (LMVD) and the overall survival (OS) or disease free survival (DFS) of CRC using meta-analysis of recent studies. PubMed and Embase databeases were searched and nine relevant studies including 799 total patients were included. Six studies including 575 patients focused on overall survival (OS) and 3 studies with 224 patients focused on disease free survival (DFS). We performed a meta-analysis to estimate the prognostic role of lymphatic microvessel density by combining separately estimated hazard ratios. A remarkable correlation between LMVD and DFS was observed in pooled analyses using a fixed-effect model (HR 2.29; 95% CI 1.11, 3.48). LMVD and OS showed a pooled HR value of 1.02 (95% CI 0.71,1.33), indicating no significant correlation between LMVD and OS. There was no evidence for significant heterogeneity or publishing bias in both DFS and OS (I2 = 0.0%, P = 0.861; I2 = 48.1%, P = 0.086, respectively). A close relationship was observed between LMVD and DFS, though no correlation between LMVD and OS was apparent. The current meta-analysis suggests that LMVD may be a poor prognostic factor for CRC patients. However, these results should be regarded cautiously and future confirmatory studies are necessary.

Myostatin induces mitochondrial metabolic alteration and typical apoptosis in cancer cells

Myostatin, a member of the transforming growth factor-β superfamily, regulates the glucose metabolism of muscle cells, while dysregulated myostatin activity is associated with a number of metabolic disorders, including muscle cachexia, obesity and type II diabetes. We observed that myostatin induced significant mitochondrial metabolic alterations and prolonged exposure of myostatin induced mitochondria-dependent apoptosis in cancer cells addicted to glycolysis. To address the underlying mechanism, we found that the protein levels of Hexokinase II (HKII) and voltage-dependent anion channel 1 (VDAC1), two key regulators of glucose metabolisms as well as metabolic stress-induced apoptosis, were negatively correlated. In particular, VDAC1 was dramatically upregulated in cells that are sensitive to myostatin treatment whereas HKII was downregulated and dissociated from mitochondria. Myostatin promoted the translocation of Bax from cytosol to mitochondria, and knockdown of VDAC1 inhibited myostatin-induced Bax translocation and apoptosis. These apoptotic changes can be partially rescued by repletion of ATP, or by ectopic expression of HKII, suggesting that perturbation of mitochondrial metabolism is causally linked with subsequent apoptosis. Our findings reveal novel function of myostatin in regulating mitochondrial metabolism and apoptosis in cancer cells.

Anorectal function after partial intersphincteric resection in ultra-low rectal cancer

AIM

To investigate the feasibility and efficacy of intersphincteric resection (ISR), in terms of postoperative anorectal function, for ultra-low rectal cancer in mainland China.

METHOD

A total of 43 patients who consecutively underwent curative partial ISR for ultra-low rectal cancer between 2006 and 2009 were enrolled in the study. Defaecatory function was assessed, using detailed questionnaires, 3, 6 and 12 months after surgery. The Wexner score was used to assess faecal continence, and anal manometry studies were performed to analyse anal sphincter function.

RESULTS

Overall defaecatory function was assessed as being satisfactory in 41 of 43 patients. Twelve months after surgery, the mean Wexner score was 4.0 ± 3.6. Anal manometry studies showed a significant change at 3 months and further, gradual, improvement over the following year. During the postoperative period, maximum squeeze pressure reached a normal value of 174.1 ± 19.5 mmHg (P = 0.041) by 6 months and resting pressure was 42.4 ± 5.6 mmHg by 12 months, which was close to the preoperative level (P = 0.038).

CONCLUSION

Because of the satisfactory recovery of defaecatory function and good oncological results, partial ISR may be recommended as an effective sphincter-preserving operation for patients with ultra-low rectal cancer.

Intranasal administration of TAT-haFGF(₁₄₋₁₅₄) attenuates disease progression in a mouse model of Alzheimer's disease

Human acidic fibroblast growth factor (haFGF), a neurotrophin-like growth factor in the brain, plays important roles in the development, differentiation and regeneration of brain neurons, which makes it potential to treat Alzheimer's disease (AD). In this study, haFGF(14-154) and TAT-haFGF(14-154) (haFGF(14-154) fused with the cell-penetrating peptide transactivator of transcription protein transduction domain (TAT-PTD)) were intranasally administrated for 5 weeks to investigate the effects on senescence-accelerated mouse prone-8 (SAMP8) mice (a mouse model of AD). Results showed that TAT-PTD could increase the concentration of haFGF in the brain significantly, and TAT-haFGF(14-154) was more effective than haFGF(14-154) in the same dosage (300 μg/kg). Importantly, TAT-haFGF(14-154) improved the learning and memory abilities of SAMP8 mice in the behavioral test, and promoted the function of cholinergic system by measuring the relevant biomarkers (acetylcholine (ACh) level, acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) activities). TAT-haFGF(14-154) also significantly reduced β-amyloid protein(1-42) (Aβ(1-42)) deposits as well as the levels of Aβ soluble forms in the mice brains and prevented the neurons from apoptosis. Besides, the oxidative stress impairment in the brain and serum was also ameliorated. The results suggest that TAT-haFGF(14-154) could attenuate the disease progression of SAMP8 AD mice, and the mechanism is related to the regulation of neurons microenvironment including neurotransmitters, Aβ pathology and oxidative stress.