Analysis of the interferences in quantitation of a site-specifically PEGylated exendin-4 analog by the Bradford method

MiR-221 Exacerbate Cell Proliferation and Invasion by Targeting TIMP3 in Papillary Thyroid Carcinoma

MiR-221 is frequently upregulated in papillary thyroid cancer (PTC) tissues and cell lines, and this study was designed to validate the association of miR-221 with PTC proliferation, apoptosis, and migration. We observed that miR-221 suppressed TIMP3 expression by binding to 3' untranslated region of TIMP3 mRNA, and TIMP3 expression was increased with the presence of miR-221 inhibitors; TIMP3 siRNA could reverse the effects of miR-221 inhibitors on PTC cells. The results indicated that miR-221 exacerbated PTC by downregulating the expression of TIMP3. The effects of miR-221 and TIMP3 in vivo were also confirmed by human PTC-bearing mice models which suggest consistent results with those in vitro studies. In summary, miR-221 could aggravate cell proliferation and invasion of PTC by targeting TIMP3.

Effect of PEG and water-soluble chitosan coating on moxifloxacin-loaded PLGA long-circulating nanoparticles

Moxifloxacin (MOX) is a Mycobacterium tuberculosis DNA gyrase inhibitor. Due to its intense hydrophilicity, MOX is cleared from the body within 24 h and required for repetitive doses which may then result in hepatotoxicity and acquisition of MOX resistant-TB, related with its use. To overcome the aforementioned limitations, the current study aimed to develop PLGA nanoparticles (PLGA NPs), to act as an efficient carrier for controlled delivery of MOX. To achieve a substantial extension in blood circulation, a combined design, affixation of polyethylene glycol (PEG) to MOX-PLGA NPs and adsorption of water-soluble chitosan (WSC) (cationic deacetylated chitin) to particle surface, was rose for surface modification of NPs. Surface modified NPs (MOX-PEG-WSC NPs) were prepared to provide controlled delivery and circulate in the bloodstream for an extended period of time, thus minimizing dosing frequency. In vivo pharmacokinetic and in vivo biodistribution following oral administration were investigated. NP surface charge was closed to neutral +4.76 mV and significantly affected by the WSC coating. MOX-PEG-WSC NPs presented striking prolongation in blood circulation, reduced protein binding, and long-drawn-out the blood circulation half-life with resultant reduced liver sequestration vis-à-vis MOX-PLGA NPs. The studies, therefore, indicate the successful formulation development of MOX-PEG-WSC NPs that showed sustained release behavior from nanoparticles which indicates low frequency of dosing.

Kanamycin Sulphate Loaded PLGA-Vitamin-E-TPGS Long Circulating Nanoparticles Using Combined Coating of PEG and Water-Soluble Chitosan

Kanamycin sulphate (KS) is a Mycobacterium tuberculosis protein synthesis inhibitor. Due to its intense hydrophilicity, KS is cleared from the body within 8 h. KS has a very short plasma half-life (2.5 h). KS is used in high concentrations to reach the therapeutic levels in plasma, which results in serious nephrotoxicity/ototoxicity. To overcome aforementioned limitations, the current study aimed to develop KS loaded PLGA-Vitamin-E-TPGS nanoparticles (KS-PLGA-TPGS NPs), to act as an efficient carrier for controlled delivery of KS. To achieve a substantial extension in blood circulation, a combined design, affixation of polyethylene glycol (PEG) to KS-PLGA-TPGS NPs and adsorption of water-soluble chitosan (WSC) (cationic deacetylated chitin) to particle surface, was raised for surface modification of NPs. Surface modified NPs (KS-PEG-WSC NPs) were prepared to provide controlled delivery and circulate in the bloodstream for an extended period of time, thus minimizing dosing frequency. In vivo pharmacokinetics and in vivo biodistribution following intramuscular administration were investigated. NPs surface charge was close to neutral +3.61 mV and significantly affected by the WSC coating. KS-PEG-WSC NPs presented striking prolongation in blood circulation, reduced protein binding, and long drew-out the blood circulation half-life with resultant reduced kidney sequestration vis-à-vis KS-PLGA-TPGS NPs. The studies, therefore, indicate the successful formulation development of KS-PEG-WSC NPs with reduced frequency of dosing of KS indicating low incidence of nephrotoxicity/ototoxicity.

TGF-β1/Smad3 Signaling Pathway Suppresses Cell Apoptosis in Cerebral Ischemic Stroke Rats

BACKGROUND We desired to observe the changes of transforming growth factor-β1/drosophila mothers against decapentaplegic protein (TGF-β1/Smad3) signaling pathway in the hippocampus region of cerebral ischemic stroke rats so that the effects of this pathway on nerve cells can be investigated. MATERIAL AND METHODS The ischemic stroke models were built by middle cerebral artery occlusion (MCAO) in vivo and oxygen-glucose deprivation (OGD) in vitro. TGF-β1 and TGF-β1 inhibitors were injected into rat models while TGF-β1, TGF-β1 siRNA, Smad3, and Smad3 siRNA were transfected into cells. Infarct sizes were measured using triphenyltetrazolium chloride (TTC) staining, while the apoptosis rate of cells were calculated by Annexin V-fluorescein isothiocyanate/propidium iodide (Annexin V-FITC/PI) staining. Levels of TGF-β1, Smad3, and Bcl-2 were examined by real-time polymerase chain reaction (RT-PCR), immunohistochemical, and Western blot analysis. RESULTS The expressions of TGF-β1/Smad3 signal pathway were significantly increased in both model rats and BV2 cells, whereas the expression of Bcl-2 was down-regulated (P<0.05). The TGF-β1/Smad3 signal pathway exhibited protective effects, including the down-regulation of infarction size in cerebral tissues and the down-regulation of apoptosis rate of BV2 cells by increasing the expression of Bcl-2 (P<0.05). In addition, these effects could be antagonized by the corresponding inhibitors and siRNA (P<0.05). CONCLUSIONS The TGF-β1/Smad3 signaling pathway was up-regulated once cerebral ischemic stroke was simulated. TGF-β1 may activate the expression of Bcl-2 via Smad3 to suppress the apoptosis of neurons.

Influence of miR-155 on Cell Apoptosis in Rats with Ischemic Stroke: Role of the Ras Homolog Enriched in Brain (Rheb)/mTOR Pathway

Background

We designed and carried out this study to examine the role of miR-155 and the Rheb/mTOR pathway in ischemic stroke. We also investigated how these two elements interact with each other and contribute to injuries resulting from ischemic stroke.

Material/Methods

We used both a middle cerebral artery occlusion rat model in vivo and an oxygen-glucose deprivation cell model in vitro to simulate the onset of ischemic stroke. miR-155 mimics, miR-155 inhibitors, and Rheb siRNA were transfected to alter the expression of miR-155 and Rheb. Infarct sizes were measured using magnetic resonance imaging (MRI) and triphenyltetrazolium chloride (TTC) staining; cell apoptosis rates were calculated using Annexin V-FITC/PI staining and flow cytometry. Levels of miR-155, Rheb, mTOR, and S6K were examined by RT-PCR, immunofluorescence, and western blot. We performed a luciferase activity assay so that the association between miR-155 and Rheb could be fully assessed.

Results

We demonstrated that miR-155 bound the 3′-UTR of Rheb and suppressed Rheb expression. As suggested by animal models, significant cerebral infarct volumes and cell apoptosis were induced by increased expression of miR-155 and decreased expression of Rheb, mTOR, and p-S6K (P<0.05). miR-155 inhibitors exhibited protective effects on ischemic stroke, including down-regulation of infarction size in cerebral tissues in vivo and reduced apoptosis of BV2 cells in vitro with increased expression of Rheb, mTOR and p-S6K (P<0.05). These protective effects could be substantially antagonized by the transfection of Rheb siRNA (P<0.05).

Conclusions

Inhibition of miR-155 may play protective roles in ischemic stroke by phosphorylating S6K through the Rheb/mTOR pathway.

MiR-31 Regulates Rho-Associated Kinase-Myosin Light Chain (ROCK-MLC) Pathway and Inhibits Gastric Cancer Invasion: Roles of RhoA

Background

This study evaluated how the expression of miR-31 can be used to detect gastric cancer (GC) to help illuminate the role of miR-31 and RhoA in GC cells.

Material/Methods

We carried out our experiments using tissue specimens from 70 GC patients. The relative expression of miR-31 and RhoA mRNA in tissues and cells was detected by RT-PCR. The expression level of RhoA protein was detected by immunohistochemistry. GC cell line BGC-823 was transfected with six groups of vectors: blank group, NC (negative control) group, miR-31 mimics group, miR-31 mimics + RhoA group, miR-31 mimics + ROCK group, and miR-31 mimics + MLCK agonist group. AGS cells were also transfected with six groups of vectors: blank group, NC group, miR-31 inhibitor group, miR-31 inhibitor + RhoA siRNA group, miR-31 inhibitor + ROCK siRNA group, and miR-31 inhibitor + MLCK inhibitor group. Transwell assay was performed to detect the invasion and migration of cells. The protein expression in different transfected groups was detected using Western blotting.

Results

GC tissues exhibited significantly lower levels of miR-31 expression compared to pericarcinous tissues (p<0.01). Moreover, a significantly higher expression of RhoA in GC tissues was observed (p<0.05). MiR-31 inhibited RhoA expression by binding to 3′UTR of mRNA, whereas miR-31 mimics significantly decreased the number of invaded and migrated cells (p<0.05). The activation of RhoA, ROCK, and phosphorylation of MLC remarkably exacerbate the invasion and migration ability of GC cells (p<0.05).

Conclusions

We found miR-31 could downregulate the ROCK/MLC pathway by inhibiting the expression of RhoA in order to suppress the invasion and migration of GC cells.

Comparative study of kanamycin sulphate microparticles and nanoparticles for intramuscular administration: preparation in vitro release and preliminary in vivo evaluation

Kanamycin sulphate (KS) is a Mycobacterium tuberculosis protein synthesis inhibitor. KS is polycationic, a property responsible for KS poor oral absorption half-life (2.5 h) and rapid renal clearance, which results in serious nephrotoxicity/ototoxicity. The current study aimed to develop KS-loaded PLGA vitamin-E-TPGS microparticles (MPs) and nanoparticles (NPs) to reduce the dosing frequency and dose-related adverse effect. In vitro release was sustained up to 10 days for KS PLGA-TPGS MPs and 13 days for KS PLGA-TPGS NPs in phosphate-buffered saline (PBS) pH 7.4. The in vivo pharmacokinetic test in Wistar rats showed that the AUC_0-∞ of KS PLGA-TPGS NPs (280.58 μg/mL*min) was about 1.62-fold higher than that of KS PLGA-TPGS MPs (172.30 μg/mL*min). Further, in vivo protein-binding assay ascribed 1.20-fold increase in the uptake of KS PLGA-TPGS NPs through the alveolar macrophage (AM). The studies, therefore, could provide another useful tool for successful development of KS MPs and NPs.

Effects of mir-21 on Cardiac Microvascular Endothelial Cells After Acute Myocardial Infarction in Rats: Role of Phosphatase and Tensin Homolog (PTEN)/Vascular Endothelial Growth Factor (VEGF) Signal Pathway

Background

This study investigated how miR-21 expression is reflected in acute myocardial infarction and explored the role of miR-21 and the PTEN/VEGF signaling pathway in cardiac microvascular endothelial cells.

Material/Methods

We used an in vivo LAD rat model to simulate acute myocardial infarction. MiR-21 mimics and miR-21 inhibitors were injected and transfected into model rats in order to alter miR-21 expression. Cardiac functions were evaluated using echocardiographic measurement, ELISA, and Masson staining. In addition, lenti-PTEN and VEGF siRNA were transfected into CMEC cells using standard procedures for assessing the effect of PTEN and VEGE on cell proliferation, apoptosis, and angiogenesis. MiR-21, PTEN, and VEGF expressions were examined by RT-PCR and Western blot. The relationship between miR-21 and PTEN was determined by the luciferase activity assay.

Results

We demonstrated that miR-21 bonded with the 3′-UTR of PTEN and suppressed PTEN expressions. Established models significantly induced cardiac infarct volume and endothelial injury marker expressions as well as miR-21 and PTEN expressions (P<0.05). MiR-21 mimics exhibited significantly protective effects since they down-regulated both infarction size and injury marker expressions by increasing VEGF expression and inhibiting PTEN expression (P<0.05). In addition, results from in vitro research show that lenti-PTEN and VEGF siRNA can notably antagonize the effect of miR-21 on cell proliferation, apoptosis, and angiogenesis (P<0.05).

Conclusions

MiR-21 exerts protective effects on endothelial injury through the PTEN/VEGF pathway after acute myocardial infarction.

Inhibition of MiR-92a May Protect Endothelial Cells After Acute Myocardial Infarction in Rats: Role of KLF2/4

Background

This study was designed to investigate the effects of microRNA-92 (miR-92), Kruppel-like factor 2 (KLF2), and Kruppel-like factor 4 (KLF4) on endothelial injury after acute myocardial infarction (AMI).

Material/Methods

Blood samples were collected from 50 AMI patients for detection of cardiac troponin I (cTnI), heart-type fatty acid-binding protein (H-FABP), and von Willebrand factor (vWF). The Sprague-Dawley rat models of AMI (n=30) were established by ligating their left anterior descending coronary artery. The cardiac markers of AMI patients and rat models were analyzed with enzyme-linked immunosorbent assay and immunohistochemistry. Human umbilical vein endothelial cells were processed into 5 groups: control, negative control, miR-92a inhibitors, miR-92a inhibitors + KLF2 small interfering RNA (siRNA), and miR-92a inhibitors + KLF4 siRNA. Cell proliferation and apoptosis were detected using MTT assay and flow cytometry. RT-PCR and Western blot were conducted to analyze KLF2 and KLF4 expressions.

Results

AMI patients exhibited significantly higher expression of both endothelial injury markers (e.g., cTnI, H-FABP, vWF) and miR-92a in blood samples, when compared with controls (P<0.05). Model rats also had similar expressional tendencies, along with lower KLF2 and KLF4 expressions (P<0.05). Further, it could be observed in cellular experiments that treatment of miR-92a mimics can further upregulate endothelial injury markers, and miR-92a and both KLF2 and KLF4 were downregulated by miR-92a mimics (all, P<0.05). Also, the luciferase activity assay confirmed the direct binding of miR-92a to 3′ UTR of KLF2/4.

Conclusions

MiR-92a was involved in the endothelial injury process after AMI and was able to suppress KLF2 and KLF4 expression.

Effects of Rosuvastatin and MiR-126 on Myocardial Injury Induced by Acute Myocardial Infarction in Rats: Role of Vascular Endothelial Growth Factor A (VEGF-A)

BACKGROUND The present study investigated the effects of VEGF-A targeted by miR-126 on myocardial injury after acute myocardial infarction (AMI) in rats, along with the contributions of rosuvastatin to the synergic effect. MATERIAL AND METHODS SD rats were obtained to construct AMI models by ligating their left anterior descending coronary arteries (LAD). We conducted echocardiography to check the 6 involved indexes: left ventricular ejection fractions (LVEF), fractional shortening (FS), left ventricular end-systolic volume (LVV), left ventricular end-diastolic volume (LVVd), cardiac output (CO), and heart rate (HR). Moreover, antibody sandwich enzyme-linked immunosorbent assay was carried out to determine MI markers: creatine kinase (CK), CK Isoenzyme (CK-MB), and Troponin I (cTn I). Dual-Luciferase Reporter Assay was performed to confirm the targeting of miR-126 and VEGF-A. MTT assay provided insight into the proliferation of myocardial fibroblasts. Finally, RT-RCR and Western blot were used for the detection of miR-126 and VEGF-A expressions in vivo and in vitro. RESULTS Luciferase activity assay showed that miR-126 transfection significantly decreased the relative luciferase activity in HEK293T cells when it was bound to normal 3' UTR of VEGF-A (P<0.05). In comparison to the control group, rats in the AMI model group had significantly lower LVEF, FS, and CO, and substantially higher LVVs, LVVd, HR, CK/U, CK-MB/U, and cTn-1/U (all P<0.05). Down-regulated miR-126 and up-regulated VEGF-A were also observed in MI models (P<0.05). CONCLUSIONS miR-126 and rosuvastatin have protective effects on AMI risk, and VEGF-A antagonizes effects on AMI is imposed by.

Evaluation of colorimetric assays for analyzing reductively methylated proteins: Biases and mechanistic insights

Colorimetric protein assays, such as the Coomassie blue G-250 dye-binding (Bradford) and bicinchoninic acid (BCA) assays, are commonly used to quantify protein concentration. The accuracy of these assays depends on the amino acid composition. Because of the extensive use of reductive methylation in the study of proteins and the importance of biological methylation, it is necessary to evaluate the impact of lysyl methylation on the Bradford and BCA assays. Unmodified and reductively methylated proteins were analyzed using the absorbance at 280 nm to standardize the concentrations. Using model compounds, we demonstrate that the dimethylation of lysyl ε-amines does not affect the proteins' molar extinction coefficients at 280 nm. For the Bradford assay, the responses (absorbance per unit concentration) of the unmodified and reductively methylated proteins were similar, with a slight decrease in the response upon methylation. For the BCA assay, the responses of the reductively methylated proteins were consistently higher, overestimating the concentrations of the methylated proteins. The enhanced color formation in the BCA assay may be due to the lower acid dissociation constants of the lysyl ε-dimethylamines compared with the unmodified ε-amine, favoring Cu(II) binding in biuret-like complexes. The implications for the analysis of biologically methylated samples are discussed.

Expression and significance of DOK2 in colorectal cancer

A reduction in the levels of docking protein 2 (DOK2) expression has previously been reported in lung adenocarcinoma and gastric cancer, indicating that this protein acts as a tumor suppressor in solid tumors. The aim of the current study was to determine the significance of DOK2 in colorectal cancer. The study consisted of 102 patients who underwent curative surgery for colorectal cancer. Histopathological and immunohistochemical analysis of DOK2 protein expression levels was performed in issue samples, and univariate and multivariate analyses were used to investigate the correlation between prognosis and the clinicopathological parameters. DOK2 expression was confirmed in the normal colorectal mucosa tissues, which is consistent with the literature, whereas 34 out of 102 (33.3%) tumor specimens were negative. The results revealed that recurrence was more likely to develop in DOK2(−) patients compared with DOK2(+) patients. The DOK2(−) patients also exhibited a poorer five-year overall survival rate (59.1%) compared with the DOK2(+) group (76.4%; P=0.0328). These results indicate that DOK2 may potentially be used as a marker of poor prognosis in patients with colorectal cancer following curative resection.