Effects of autophagy inhibitor 3-methyladenine on a diabetic mice model

AIM

To investigate the role of autophagy inhibitor 3-methyladenine (3-MA) on a diabetic mice model (DM) and the potential mechanism.

METHODS

Male C57BL/6J mice were randomly divided into a normal control group (NC group) and an DM group. DM were induced by multiple low-dose intraperitoneal injection of streptozotocin (STZ) 60 mg/kg·d for 5 consecutive days. DM mice were randomly subdivided into untreated group (DM group), 3-MA (10 mg/kg·d by gavage) treated group (DM+3-MA group) and chloroquine (CQ; 50 mg/kg by intraperitoneal injection) treated group (DM+CQ group). The fasting blood glucose (FBG) levels were recorded every week. At the end of experiment, retinal samples were collected. The expression levels of pro-apoptotic proteins cleaved caspase-3, cleaved poly ADP-ribose polymerase 1 (PARP1) and Bax, anti-apoptotic protein Bcl-2, fibrosis-associated proteins Fibronectin and type 1 collagen α1 chain (COL1A1), vascular endothelial growth factor (VEGF), inflammatory factors interleukin (IL)-1β and tumor necrosis factor (TNF)-α, as well as autophagy related proteins LC3, Beclin-1 and P62 were determined by Western blotting. The oxidative stress indicators 8-hydroxydeoxyguanosine (8-OHdG) and malondialdehyde (MDA) were detected by commercial kits.

RESULTS

Both 3-MA and CQ had short-term hypoglycemic effect on FBG and reduced the expression of VEGF and inflammatory factors IL-1β and TNF-α in DM mice. 3-MA also significantly alleviated oxidative stress indicators 8-OHdG and MDA, decreased the expression of fibrosis-related proteins Fibronectin and COL1A1, pro-apoptotic proteins cleaved caspase-3, cleaved PARP1, as well as the ratio of Bax/Bcl-2. CQ had no significant impact on the oxidative stress indicators, fibrosis, and apoptosis related proteins. The results of Western blotting for autophagy related proteins showed that the ratio of LC3 II/LC3 I and the expression of Beclin-1 in the retina of DM mice were decreased by 3-MA treatment, and the expression of P62 was further increased by CQ treatment.

CONCLUSION

3-MA has anti-apoptotic and anti-fibrotic effects on the retina of DM mice, and can attenuate retinal oxidative stress, VEGF expression and the production of inflammatory factors in the retina of DM mice. The underlying mechanism of the above effects of 3-MA may be related to its inhibition of early autophagy and hypoglycemic effect.

Neuropilin1, a novel independent prognostic factor and therapeutic target in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer, and thus, has limited treatment options. Neuropilin1 (NRP1) is a multi-functional transmembrane protein that interacts with a number of signaling receptors and plays an important role in cancer progression. Previous studies demonstrated that the expression of NRP1 is activated and promotes the progression of breast cancer particularly in TNBC compared to other molecular subtypes; however, whether or not the level of NRP1 expression is related to the progression of TNBC warrants further study. In the current study, we determined the expression and function of NRP1 and evaluated the clinical significance of NRP1 in patients with TNBC. In addition, we determined whether or not an NRP1 antagonist potentiates the inhibitory effects of paclitaxel (PTX) in patients with TNBC. In our clinical study, NRP1 had higher expression in TNBC tissues than non-TNBC tissues at the same stage, and NRP1 was an independent prognostic factor. Specifically, the high expression of NRP1 was associated with shorter survival in TNBC patients. In addition, TNBC cells treated with NRP1 antagonist significantly potentiated the effect of PTX on cell proliferation, cell migration, and apoptosis. Our findings suggest that NRP1 expression can act as an independent prognostic factor for TNBC patients, and the combination of PTX and an NRP1 antagonist may be an effective treatment regimen for TNBC.

[Quantitative comparison of diffusion weighted image in liver at two field strengths for chronic hepatitis B]

Objective: To evaluate whether there were differences between apparent diffusion coefficient (ADC) values derived from 3.0 T and 1.5 T MR diffusion-weighted imaging (DWI) in liver of patients with chronic hepatitis B. Methods: From January 2016 to November 2016, a total of 40 chronic hepatitis B prospectively underwent both 1.5 T and 3.0 T DWI before liver biopsy, the interval between two scans was within 15 minutes, the protocol was respiratory-triggered DWI(RT-DWI). The ADC values were measured at both field strengths using ROI method. Bland-Altman tests and paired t-tests were used to compare ADC values obtained at 1.5 T and 3.0 T. Results: The ADC values of different b values for patients with mild inflammation at 1.5 T were(1.22-1.48(1.35±0.08)×10(-3) mm(2)/s), the ADC values of different b values for patients with mild inflammation at 3.0 T were(1.18-1.45(1.30±0.08)×10(-3) mm(2)/s); the ADC values of different b values for patients with moderate to severe inflammation at 1.5 T were(1.11-1.37(1.25±0.06)×10(-3) mm(2)/s), the ADC values of different b values for patients with moderate to severe inflammation at 3.0 T were(1.08-1.31(1.20±0.06)×10(-3) mm(2)/s). There were significantly differences between the ADC values of different b values for patients with chronic hepatitis B obtained at two field strengths (P<0.01). Conclusions: Different field strengths have influence on ADC values in liver, the ADC values derived from 3.0 T are lower than the ADC values derived from 1.5 T.

[Study of diffusion weighted imaging in combination with conventional MRI signs for inflammation activity of chronic hepatitis B]

Objective: To study the correlation between ADC values of diffusion weighted imaging (DWI) and the pathological grading in inflammation activity of chronic hepatitis B, and combined with conventional MRI features to predict the diagnosis effectiveness. Methods: A total of 142 cases of patients with chronic hepatitis B were selected as inflammatory group in 302 Hospital of PLA from January 2014 to December 2015, while 20 cases of healthy subjects without history of liver disease were chosen as control group.All patients underwent MR plain scan and dynamic contrast enhancement and DWI examinations (b=0, 800 s/mm(2)) for liver, and were performed liver biopsy within two days.According to the degree of inflammation activity (G), the inflammation group was divided into G1, G2 and G3-4 level.The apparent diffusion coefficient (ADC) value, and the MRI features of each group were analyzed. Results: The ADC values showed statistical difference (F=8.392, P<0.01) within inflammation group of chronic hepatitis B from different pathologic grading, and there was significant negative correlation between ADC values and liver inflammation activity grading (r=-0.613, P<0.01). The ADC value of inflammation group and control group was (1.31±0.16), (1.12±0.15)×10(-3) mm(2)/s, the difference was statistically significant (P<0.05). The ADC value of G1, G2 and G3-4 level was (1.22±0.12), (1.05±0.12), (0.98±0.10)×10(-3) mm(2)/s respectively, and there was statistical difference (P<0.05) between G1 and G2, G1 and G3-4. The receiver operating characteristic (ROC) curve in diagnosis of equal and above G2 level showed the area under the curve (AUC) was 0.880, the sensitivity and the specificity was 82.4% and 76.8% respectively, the diagnostic cut-off value was 1.09×10(-3) mm(2)/s.Besides, the detection rate of portal around its orbit and gallbladder wall edema in inflammation group had statistical difference (P<0.05), and there was no statistical difference in the detection rate of abnormal liver arterial enhancement, hilus lymph node increases and ascites in inflammation group(P>0.05). The ROC in diagnosis of equal and above G2 level by ADC values combined with the MRI characteristic signs showed AUC was 0.938, the sensitivity and the specificity was 88.4% and 88.9% respectively. Conclusions: ADC values can predict the inflammation activity of chronic hepatitis B with quantitatively and non-invasively.Combining with characteristic MRI signs, ADC values can improve the diagnosis efficiency.

Characterization of metallothioneins (MT-I and MT-II) in the yak

The cDNA-encoding sequences for yak metallothionein isoforms I (MT-I) and II (MT-II) were amplified and cloned by reverse-transcription PCR to characterize the nucleotide sequence and protein structure of metallothionein in the yak. The cDNA sequences of MT-I and MT-II were subjected to BLAST searching at the National Center for Biotechnology Information, and the results indicated that the nucleotide sequences of yak MT-I and MT-II, when compared among different species of mammals, are highly conserved. The yak open reading frames have a length of 183 nucleotides, which encode for yak MT-I and MT-II proteins of 61 AA, respectively. Analysis of hydrophobicity, trans-membrane region, and signal peptides suggested that metallothioneins of the yak are nonsecretory proteins. There were several conserved tripeptide sequences, such as C-X-C, C-C-X-C-C, and C-X-X-C (X designates AA excluding cysteine in MT-I and MT-II), and they are highly conserved in their evolution. By homologous comparative modeling, we predicted the molecular spatial structures of yak MT-I and MT-II, which are composed of alpha- and beta-domains that are linked by the conserved tripeptide Lys(30)-Lys(31)-Ser(32) (KKS).

Expression of Human Trefoil Factor 3 in Pichia pastoris and Its Biological Activity Analysis

The human TFF3 (trefoil factor 3) DNA fragment was amplified by polymerase chain reaction (PCR) from human fetal placenta cDNA. The gene was cloned into the Pichia pastoris expression vector pPIC9K containing AOX 1 promoter and alpha-factor leader sequence. Multi-copies insertion transformants were screened on G418 plates. After the induction by 2% methanol for 48 hours, the expression of dimeric hTFF3 came up to 45% of total proteins in medium, as identified by SDS-PAGE and Western blot assay. The recombinant protein was further purified by S-Sepharose, Q-Sepharose ion-exchange chromatography and Sephacryl-S-100 gel filtration chromatography to the 95% purity, as shown by densitometric scanning. The N-terminus and molecular weight of the recombinant hTFF3 was in good agreement with the native hTFF3. The recombinant protein was proved to have good biological activity of preventing rats from the gastric ulcer induced by hydrochloric acid.

Fluorescence intermittency in self-assembled InP quantum dots

Fluorescence intermittency in InP self-assembled dots is investigated by means of far field imaging and single dot spectroscopy. Based on our observation that blinking dots are found in the vicinity of scratches and the blinking frequency is drastically enhanced under a near-infrared laser irradiation, we attribute the origin of the fluorescence intermittency to a local electric field due to a carrier trapped at a deep localized center in the Ga0.5In0.5P matrix. The validity of this explanation is confirmed by a thermal activation-type behavior of the switching rate and artificial reproduction of the blinking phenomenon by an external electric field.

Two metallothioneins in the fresh-water fish, crucian carp (Carassius cuvieri): cDNA cloning and assignment of their expression isoforms

Two metallothionein cDNAs (MT-A and MT-B) in the fresh-water fish crucian carp (Carassius cuvieri Temminck et Schlegel) were cloned. Sequence analysis of both cDNAs gave the structure of a coding region corresponding to 60 amino acid residues. The homology of their deduced amino acid sequences was completely conserved at the positions of the cysteine residue, but a significant difference existed in the size of their 3'-untranslated regions (130 base pairs for MT-A and 280 base pairs for MT-B). Direct amino acid sequencing of the MT-II isoform purified by HPLC was accomplished for up to 30 residues and its sequence was identical to that deduced from MT-B cDNA. This is the first case in vertebrates that N-terminal methionine in crucian carp MT-II was not blocked. By northern blot analysis, basal and cadmium chloride- or dexamethasone-induced MT-B (MT-II) mRNAs were detected time dependently after treatment. On the other hand, the expression of MT-A mRNA was extremely low. These results indicate that the MT isoform II in crucian carp is coded by the MT-B gene, and that the MT-B-dominant expression of mRNA in crucian carp may be due to the difference in the 3'-untranslated regions of MT mRNAs.

The application of in vivo confocal microscopy and tear LDH measurement in assessing corneal response to contact lens and contact lens solutions

PURPOSE

To evaluate differences in corneal response to daily wear (DW) of soft contact lens (CL) wear with different CL solutions and to assess the ability of in vivo confocal microscopy (CM) and tear lactate dehydrogenase (LDH) measurement to detect such differences in NZW rabbits.

METHODS

Daily treatment of lenses consisted of a rub and rinse cleaning, then overnight soak in one of five solutions: Sauflon All in One (ALL), Compound A (CoA), OPTI-FREE((R) )Rinsing, Disinfecting, and Storage Solution (OPT), ReNu((R)) <?Pub Caret>Multipurpose Solution (REN), and UNISOL( (R)) Saline Solution (UNI). Rabbits (4/test group) wore 71% H( 2)O/type4 soft lenses approximately 7 hours daily. On days 0, 1, 3 and 7, slit lamp examination, tear LDH measurement, and in vivo CM were performed after removal of lenses. Using in vivo CM, epithelial thickness, epithelial cell area, and stromal thickness were measured, both centrally and peripherally.

RESULTS

Epithelial thickness in ALL, CoA, and UNI-treated eyes showed a significant decrease of 15.6%, 13. 3%, and 10.6% (p < 0.05 in all groups), centrally, while CoA, OPT, and UNI showed a significant decrease of 9.3%, 7.1%, and 4.4% (p < 0. 05 in all groups), peripherally. ALL showed a significant 9.5% (p < 0.05) decrease of central cell area, while CoA showed a significant 21.5% (p < 0.01) decrease peripherally. UNI demonstrated a significant 3.2% (p < 0.05) decrease in central stromal thickness. ALL, CoA, and UNI showed a significant increase in LDH level of 152. 1%, 192.1%, and 308.2% (p < 0.05 in all groups) at day 3, respectively, but values declined at day 7. Significant changes in basal epithelial morphology were also observed with CoA on day 7 on in vivo CM.

CONCLUSIONS

Overall, lens care solutions in combination with CL wear may interact to cause increased epithelial desquamation leading to decreased surface cell area and epithelial thickness. The clinical significance of these changes will require further investigation. In vivo CM combined with tear LDH assay is a quantitative, objective, non-invasive method of assessing CL wear and CL disinfecting solution effects on the cornea, and is able to detect differences in corneal response to different CL solutions.

Induction of two major isoforms of metallothionein in crucian carp (Carassius cuvieri) by air-pumping stress, dexamethasone, and metals

The induction of metallothionein (MT) by physical and chemical stress was assessed using the fresh-water fish, crucian carp (Carassius cuvieri Temminck et Schlegel). The fish exposed to violent air-pumping stress for 6 days revealed time-dependent induction of MT-like metal-binding proteins in both their livers and kidneys. Their hepatic contents after exposure to stress were elevated to twice the basal level with 24 h, resulting in more than a 3-fold increase at 144 h, whereas their renal contents gradually increased after 24 h and reached the same level as that in the liver around 96 h. Two major inducible proteins were purified from livers of fish exposed to stress and were shown to be MT based upon their chromatographic behavior, UV absorption spectra and their molecular weights. Consequently, they were termed ccMT-1 and ccMT-2, according to their elution sequence upon anion-exchange chromatography. Both proteins mainly bound zinc in their endogenous forms and showed different immunogenicity to rat and rabbit MTs. Dexamethasone, a potent inducer for MT synthesis in mammals, induced the production of both isoforms in crucian carp, whereas cadmium and zinc ions prominently induced the synthesis of ccMT-2. These results indicate that crucian carp have the ability to produce MTs in response to various kinds of environmental stress and that violent air-pumping stress in crucian carp may induce MT synthesis, in part, via the release of endogenous factor(s), such as glucocorticoids.