Role of the ERK1/2 Signaling Pathway in Osteogenesis of Rat Tendon-Derived Stem Cells in Normoxic and Hypoxic Cultures

BACKGROUND

Ectopic ossification and increased vascularization are two common phenomena in the chronic tendinopathic tendon. The increased vascularization usually leads to an elevated local oxygen tension which is one of micro-environments that can influence differentiate status of stem cells.

OBJECTIVE

This study aimed to investigate the osteogenesis capacity of rat tendon-derived stem cells TDSCs (rTDSCs) in normoxic and hypoxic cultures, and to study the role of ERK1/2 signaling pathway in this process.

METHODS

rTDSCs were subjected to osteogenesis inductive culture in hypoxic (3% O2) and normoxic (20% O2) conditions. The inhibitor U0126 was added along with culture medium to determine the role of ERK1/2 signaling pathway. Cell viability, cell proliferation, alizarin red staining, alkaline phosphatase (AKP) activity, gene expression (ALP, osteocalcin, collagen I and RUNX2) and protein expression (p-ERK1/2 and RUNX2) of osteogenic-cultured rTSDCs were analyzed in this study.

RESULTS

Hypoxic and normoxic culture had no effects on cell viability of rTDSCs, whereas the proliferation potential of rTDSCs was significantly increased in hypoxic culture. The osteogenesis capacity of rTDSCs in normoxic culture was significantly promoted compared with hypoxic culture, which was reflected by an increased alizarin red staining intensity, an elevated ALP activity, and the up-regulated gene (ALP, osteocalcin, collagen I and RUNX2) or protein (RUNX2) expression of osteogenic makers. However, the osteogenesis capacity of rTDSCs in both hypoxic and normoxic cultures was attenuated by the inhibitor U0126.

CONCLUSION

Normoxic culture promotes osteogenic differentiation of rTDSCs compared with the hypoxic culture, and the ERK1/2 signaling pathway is involved in this process.

Effects of silencing MTA1 gene by RNA interference on invasion and metastasis of endometrial carcinoma

OBJECTIVE

The study aimed at the silence effect of MAT1 gene and proteins in Ishikawa cell of human endometrial carcinoma cell line through RNAi mediated by siRNA and also discussed the effect of MTA1 gene silence on the invasion and metastasis of endometrial carcinoma.

MATERIALS AND METHODS

According to the principle of designing siRNA sequence, siRNA aiming at MTA1 gene (MTA1-siRNA) and siRNA used for negative control (Control-siRNA) were designed and synthesized and Ishikawa cell was transfected by transfection reagents. RT-PCR method as well as western blot was used, respectively, to detect the MTA1 mRNA and protein expression of stably transfected cells. Transwell method and scarification experiment were adopted to detect the invasion and metastasis of Ishikawa cells.

RESULTS

The expression results of MTA1 on the levels of mRNA and protein showed that the expression level in transfected MTA1-siRNA group was obviously lower than that in non-transfected group and transfected control-siRNA group (p <0.05), while there was no significant difference between non-transfected group and transfected control-siRNA group (p > 0.05). Effective interference on the expression of MTA1 gene remarkably lowered the invasion and metastasis of endometrial carcinoma Ishikawa cells.

CONCLUSION

RNAi aiming at MTA1 can effectively inhibit the expression of MTA1 in endometrial carcinoma Ishikawa cells and the effective silence of MTA1 can weaken the invasion and metastasis of Ishikawa cells, which provides a new strategy for gene therapy of endometrial carcinoma and an experimental basis for inhibiting the invasion and metastasis of endometrial carcinoma.

Applications of graphene and its derivatives in intracellular biosensing and bioimaging

Graphene has a unique planar structure, as well as excellent electronic properties, and has attracted a great deal of interest from scientists.

Highly sensitive and selective detection of cadmium with a graphite carbon nitride nanosheets/Nafion electrode

A sensitive g-C₃N₄ Cd²⁺ sensor is fabricated in this paper. The linear range and detection limit for Cd²⁺ detection could be as low as 1 nM and (0.5 nM). This sensor also has excellent stability and selectivity for Cd²⁺ against interferences.

Dynamic Compression Effects on Immature Nucleus Pulposus: a Study Using a Novel Intelligent and Mechanically Active Bioreactor

BACKGROUND

Previous cell culture and animal in vivo studies indicate the obvious effects of mechanical compression on disc cell biology. However, the effects of dynamic compression magnitude, frequency and duration on the immature nucleus pulposus (NP) from an organ-cultured disc are not well understood.

OBJECTIVE

To investigate the effects of a relatively wide range of compressive magnitudes, frequencies and durations on cell apoptosis and matrix composition within the immature NP using an intelligent and mechanically active bioreactor.

METHODS

Discs from the immature porcine were cultured in a mechanically active bioreactor for 7 days. The discs in various compressive magnitude groups (0.1, 0.2, 0.4, 0.8 and 1.3 MPa at a frequency of 1.0 Hz for 2 hours), frequency groups (0.1, 0.5, 1.0, 3.0 and 5.0 Hz at a magnitude of 0.4 MPa for 2 hours) and duration groups (1, 2, 4 and 8 hours at a magnitude of 0.4 MPa and frequency of 1.0 Hz) experienced dynamic compression once per day. Discs cultured without compression were used as controls. Immature NP samples were analyzed using the TUNEL assay, histological staining, glycosaminoglycan (GAG) content measurement, real-time PCR and collagen II immunohistochemical staining.

RESULTS

In the 1.3 MPa, 5.0 Hz and 8 hour groups, the immature NP showed a significantly increase in apoptotic cells, a catabolic gene expression profile with down-regulated matrix molecules and up-regulated matrix degradation enzymes, and decreased GAG content and collagen II deposition. In the other compressive magnitude, frequency and duration groups, the immature NP showed a healthier status regarding NP cell apoptosis, gene expression profile and matrix production.

CONCLUSION

Cell apoptosis and matrix composition within the immature NP were compressive magnitude-, frequency- and duration-dependent. The relatively high compressive magnitude or frequency and long compressive duration are not helpful for maintaining the healthy status of an immature NP.

Study on the expression of VEGF and HIF-1α in infarct area of rats with AMI

OBJECTIVE

To investigate the expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1α (HIF-1α) in infarct area of rats with acute myocardial infarction (AMI).

MATERIALS AND METHODS

A total of 36 healthy male Wistar rats weighing 180 g-220 g were included in our study and were randomly divided into two groups of 6 rats each: sham operation group and experiment group. In sham operation group, surgery was performed by opening chest without ligation of arteria coronaria while, in the experiment group, surgery was performed to produce AMI model. Animals were sacrificed immediately after the operation on day 7 and day 14, respectively. The serum troponin, myocardial infarct area, microvessel density in infarct area, VEGF and HIF-1α expression were analyzed.

RESULTS

Differences in the serum troponin level, myocardial infarct area, microvessel density in infarct area, VEGF and HIF-1 expression level at different time points in sham and experiment groups had statistical significance (p < 0.05). On day 7, the serum troponin, myocardial infarct area, microvessel density in infarct area, VEGF and HIF-1 expression level were the highest and the level was second highest on day 14 while the levels were lowest immediately after the operation. The expression levels of VEGF and HIF-1α were positively related with the increasing density of microvessel in infarct area (p < 0.05).

CONCLUSIONS

The expression of VEGF and HIF-1α might be involved with myocardial remodeling and angiogenesis.

Huang-Lian-Jie-Du decoction treated sepsis via regulating ERK and SRC/STAT3 pathways and ameliorating metabolic status

LPS disturbed the metabolomic profiles and activated the ERK and SRC/STAT3 signaling pathways of mice, and HLJDD exerted therapeutic effects on sepsis induced by LPS.

Longitudinal Association between Selenium Levels and Hypertension in a Rural Elderly Chinese Cohort

OBJECTIVES

Results from previous studies have been inconsistent on the association between selenium and hypertension, and very few studies on this subject have focused on the elderly population. The purpose of this study is to examine the relationship between selenium level and hypertension in a rural elderly Chinese cohort.

DESIGN

A longitudinal study was implemented and data were analyzed using logistic regression models and Cox proportional hazards regression model adjusting for potential confounders. The associations between selenium level and prevalent hypertension at baseline and between selenium and incident hypertension were examined.

SETTING

Community-based setting in four rural areas in China.

SUBJECTS

A total of 2000 elderly aged 65 years and over (mean 71.9±5.6 years) participated in this study.

MEASUREMENTS

Nail selenium levels were measured in all subjects at baseline. Blood pressure measures and self-reported hypertension history were collected at baseline, 2.5 years and 7 years later. Hypertension was defined as systolic blood pressure 140 mmHg or higher, diastolic blood pressure 90 mmHg or higher, or reported use of anti-hypertensive medication.

RESULTS

The rate of baseline hypertension was 63.50% in this cohort and the mean nail selenium level is 0.413±0.183μg/g. Multi-covariate adjusted cross-sectional analyses indicated that higher selenium level was associated with higher blood pressure measures at baseline and higher rates of hypertension. For the 635 participants with normal blood pressure at baseline, 360 had developed hypertension during follow-up. The incidence rate for hypertension was 45.83%, 52.27%, 62.50%, 70.48%, and 62.79% from the first selenium quintile to the fifth quintile respectively. Comparing to the lowest quintile group, the hazard ratios were 1.41 (95%CI: 1.03 to1.94), 1.93 (95%CI: 1.40 to 2.67), 2.35 (95%CI: 1.69 to 3.26) and 1.94 (95%CI: 1.36 to 22.77) for the second selenium quintile to the fifth quintile respectively.

CONCLUSIONS

Our findings suggest that high selenium may play a harmful role in the development of hypertension. Future studies are needed to confirm our findings and to elucidate a plausible biological mechanism.

Hybrid biofilm-membrane bioreactor (Bf-MBR) for minimization of bulk liquid-phase organic substances and its positive effect on membrane permeability

Four biofilm membrane bioreactors (Bf-MBRs) with various fixed carrier volumes (C:M) were operated in parallel to investigate the effect of attached-growth mode biomass involvement to the change of liquid-phase organics characteristics and membrane permeability, by comparing with conventional MBR. The experiments displayed that C:M and co-existence of biofilm with suspended solids in Bf-MBRs resulted in slight difference in pollutants removal effectiveness, and in rather distinct biomass properties and bacterial activities. The membrane permeability and specific resistance of bulk suspension of Bf-MBRs related closely with the liquid-phase organic substance, including soluble microbial products (SMP) and biopolymer cluster (BPC). Compared with conventional MBR, Bf-MBR with proper C:M had a low total biomass content and food-chain, where biofilm formation and its dominance affected liquid-phase organics, especially through reducing their content and minimizing strongly and weakly hydrophobic components with small molecular weight, and thus to mitigate membrane fouling significantly.

miR-21 regulates tumor progression through the miR-21-PDCD4-Stat3 pathway in human salivary adenoid cystic carcinoma

miR-21, which is a putative tumor onco-miR and frequently overexpressed microRNA in various tumors, has been linked to tumor progression through targeting of tumor-suppressor genes. In this study, we sought to determine whether miR-21 has any role on tumor progression of salivary adenoid cystic carcinoma (SACC) and the possible mechanisms. We found that the level of miR-21 expression was significantly higher in SACC than that in normal salivary tissues, and it is also higher in tumors with metastasis than that without metastasis. Using an anti-miR-21 inhibitor in an in vitro model, downregulation of miR-21 significantly decreased the capacity of invasion and migration of SACC cells, whereas a pre-miR-21 increased the capacity of invasion and migration of SACC cells. To explore the potential mechanisms by which miR-21 regulate invasion and migration, we identified one direct miR-21 target gene, programmed cell death 4 (PDCD4), which has been implicated in invasion and metastasis. The suppression of miR-21 in metastatic SACC-LM cells significantly increased the report activity of PDCD4 promoter and the expression of PDCD4 protein. This subsequently resulted in downregulation of the p-STAT3 protein. The level of miR-21 expression positively related to the expression of PDCD4 protein and negatively related to the expression of p-STAT3 protein in SACC specimens, respectively, indicating the potential role of the STAT3-miR-21-PDCD4 pathway in these tumors. Dysregulation of miR-21 has an important role in tumor growth and invasion by targeting PDCD4. Therefore, suppression of miR-21 may provide a potential approach for the treatment of advanced SACC patients.

Discovery of kokumi peptide from yeast extract by LC-Q-TOF-MS/MS and sensomics approach

BACKGROUND

Yeast extract can impart thickness, complexity and long-lasting taste impression, coined kokumi taste, to blank chicken broth. In this research, the kokumi-active peptide in yeast extract was discovered by ultrafiltration, liquid chromatographic and quadrupole-time-of-flight-tandem mass spectrometric technologies. Furthermore, the sensory characters of these peptides were evaluated by a sensomics approach.

RESULTS

A total of 10 kokumi peptides were identified from yeast extract. They were γ-Glu-Cys-Gly, γ-Glu-Leu, γ-Glu-Val, γ-Glu-Tyr, Leu-Lys, Leu-Gln, Leu-Ala, Leu-Glu, Leu-Thr and Ala-Leu. Apart from the well-known kokumi-active glutathione and γ-glutamyl dipeptides, five leucyl dipeptides were first proposed having kokumi activity. Among them, Ala-Leu was found to have the highest kokumi threshold concentration (1.5 mmol L(-1) ) in the blank chicken broth, while Leu-Glu was the lowest (0.3 mmol L(-1) ). A subsequent dose-response experiment indicated that the bitter-tasting leucyl dipeptides could impart kokumi taste to chicken broth at low concentrations (less than bitter threshold concentrations). Interestingly, the kokumi sensation began to decrease when such peptides exceeded the threshold concentration by approximately 16-fold in the blank chicken broth.

CONCLUSION

Key kokumi-active fractions were purified from yeast extract. Among them, ten important kokumi peptides from yeast extract were identified.

Distribution of Cryptosporidium species in Tibetan sheep and yaks in Qinghai, China

Few data are available on the distribution of Cryptosporidium species in Tibetan sheep and yaks, which are free-range animals living in a cold, low oxygen, and high ultraviolet radiation habitat. In this study, 904 fecal specimens were collected from 350 Tibetan sheep and 554 yaks in six counties. Cryptosporidium spp. were detected and differentiated by PCR and sequence analyses. Altogether, 43 (12.3%) Tibetan sheep and 158 (28.5%) yaks were positive for Cryptosporidium spp. In Tibetan sheep, Cryptosporidium xiaoi (39/43, 90.7%) was the dominant species, with the remaining cases (4/43, 9.3%) by Cryptosporidium ubiquitum. All C. ubiquitum specimens belonged to the subtype family XIIa. In contrast, Cryptosporidium andersoni (72/158, 45.6%), Cryptosporidium bovis (47/158, 29.7%), Cryptosporidium ryanae cattle type (35/158, 22.2%), C. ryanae buffalo type (2/158, 1.3%), and Cryptosporidium suis-like (2/158, 1.3%) were identified in yaks. Contradictory to previous observations, C. andersoni was one of the dominant Cryptosporidium species in yaks in this study. Despite sharing habitats, Tibetan sheep and yaks are evidently infected with different Cryptosporidium species.

Development of transcript-associated microsatellite markers in Ancherythoculter nigrocauda and cross-amplification in Culter alburnus

Twenty-eight polymorphic microsatellite markers were developed from the transcriptome of Ancherythoculter nigrocauda. These loci were used to characterize the genotypes of 48 individuals. The observed number of alleles per locus ranged from 5 to 11, with an average of 7.7. Expected and observed heterozygosities ranged from 0.437 to 0.978 and from 0.373 to 1.000, respectively. Four of these polymorphic microsatellite loci (HWB14, HWB18, HWB24, and HWB30) deviated significantly from the Hardy-Weinberg equilibrium after use of the sequential Bonferroni correction (P < 0.05). Twenty of the 28 loci could be successfully amplified in Culter alburnus. These novel markers will be useful for germplasm resource conservation and management of A. nigrocauda and C. alburnus.

Increasing production of matrix metalloproteinases, tumor necrosis factor-α, vascular endothelial growth factor and prostaglandin E2 in rheumatoid arthritis synovial fibroblasts by different adiponectin isoforms in a concentration-dependent manner

Adipokines have been known to play a significant role in rheumatic disease via synovial fibroblasts. However, to date, the concentration effects of adiponectin isoforms on the pathophysiology of rheumatoid arthritis (RA) have not been extensively studied. Therefore, the present study examined the different effects of the adiponectin isoforms on rheumatoid arthritis synovial fibroblasts (RASF) and investigated the relations between the concentration of individual adiponectin isoforms and the production of the inflammatory factors of RASF. Articular synovial tissues were obtained from the patients fulfilled with diagnostic criteria of RA, and health people. RASF and human fibroblast&mdash;like synoviocytes (HFLS) were isolated and cultured. They were stimulated with increasing concentrations of 25 &#956;g/ml, 50 &#956;g/ml, and 100&#956;g/ml of different human adiponectin isoforms. The levels of matrix metalloproteinase (MMP)&mdash;3, MMP&mdash;10, tumor necrosis factor (TNF)&mdash;&#945;, vascular endothelial growth factor (VEGF), and prostaglandin E2 (PGE2) in culture supernatants were measured by immunoassays. The results showed the levels of MMP&mdash;3, MMP&mdash;10, TNF&mdash;&#945;, VEGF and PGE2 were significantly increased in RASF which were treated with individual adiponectin isoforms compared to untreated RASF (p&lt;0.01), and the increases also had significances compared to HFLS which were treated with the same conditions (p&lt;0.05). Moreover, the effect of HMW (high molecular weight)/ MMW (middle molecular weight) was the strongest among them. In conclusion, all three adiponectin isoforms may contribute to proinflammatory effect by stimulating the production of MMP&mdash;3, MMP&mdash;10, TNF&mdash;&#945;, VEGF and PGE2 of RASF in a concentration&mdash;dependent manner. HMW/MMW adiponectin could play an important role in matrix destroying and synovial vascular creating of the pathology of RA.