Exploring the ability of TAT, a cell-penetrating peptide, to deliver proteins in a non-fused form / 药学学报

Accumulating evidence has shown that the cell-penetrating peptide TAT can be applied to deliver different types of drug molecules, including nucleic acids, proteins and small molecule drugs. Usually TAT delivers cargoes on the basis of their covalent bonds or non-covalent interactions. However, there are few reports on the delivery of proteins by TAT in a non-covalent manner, and no quantitative comparisons have been made on the protein delivery ability of TAT in fusion and non-fusion manners. In order to explore the ability of TAT to deliver proteins in non-fusion manner, here we used fluorescence microscopy and flow cytometry to investigate the ability of TAT to deliver enhanced green fluorescent protein (EGFP) into non-small cell lung cancer cells A549 in a non-fusion manner. It was found that TAT could deliver EGFP into A549 cells, and its delivery ability was positively correlated with its concentration. In addition, the fusion protein TAT-EGFP was overexpressed and purified, and its permeability across cell membrane was also investigated. In this paper, based on quantitative comparison, we found that the delivery of EGFP by TAT in fusion manner is significantly efficient than that of TAT in non-fusion manner. This is the report that TAT can deliver EGFP in a non-fusion manner. Although its delivery efficiency remains to be improved as compared with the fusion manner, the non-fusion manner has shown incomparable advantages in ease of operation, suggesting that it is also a candidate for delivery strategy in the future.

Development of morphology engineering for production of bio-based chemicals / 生物工程学报

Synthetic biology and metabolic engineering have been widely used to construct microbial cell factories for efficient production of bio-based chemicals, which mainly focus on the modification and regulation of metabolic pathways. The characteristics of microorganisms themselves, e.g. morphology, have rarely been taken into consideration in the biotechnological production processes. Morphology engineering aims to control cell shapes and cell division patterns by manipulating the genes related to cell morphology, providing a new strategy for developing efficient microbial cell factories. This review summarized the proteins related to cell morphology, followed by illustrating a few examples of using morphology engineering strategies for improving production of bio-based chemicals. This includes increasing intracellular product accumulation by regulating cell size, enhancing extracellular secretion of target products by improving cell permeability, reducing production cost by achieving high cell density, and improving product performance by controlling the degree of product hydrolysis. Finally, challenges and perspectives for the development of morphology engineering were discussed.

Mechanism of hif-1α mediated hypoxia-induced permeability changes in bladder endothelial cells

This study aimed to investigate the mechanism of hypoxia-inducible factor-1 alpha (HIF-1α) mediated hypoxia-induced permeability changes in bladder endothelial cells. Models of in vitro hypoxic cell culture of bladder cancer, bladder cancer cells with low HIF-1α expression and HIF-1α RNA interference (RNAi) expression vector were established. Western blot and reverse transcription polymerase chain reaction (RT-PCR) were used to detect the expression of HIF-1α and vascular endothelial growth factor (VEGF) in each group. Bladder cell permeability was determined. Results showed that protein and mRNA expression of HIF-1α and VEGF at 3 and 12 h of hypoxia were significantly higher than normal control (P<0.05), and peaked at 12 h. HIF-1α and VEGF expression in the hypoxic group and hypoxic+3-(5′-hydroxymethyl-2′-furyl)-1-benzyl indazole (YC-1) group were significantly higher than normal control (P<0.05), while expression in the hypoxic+YC-1 group was significantly lower than the hypoxic group (P<0.05). Bladder cell permeability in the hypoxic and hypoxic+YC-1 group were significantly increased compared to normal control (P<0.05), while in the hypoxic+YC-1 group was significantly decreased compared to the hypoxic group (P<0.05). Most of the cells in the stably transfected HIF-1α RNAi expression vector pcDNA6.2-GW/EmGFP-miR-siHIF-1α expressed green fluorescence protein (GFP) under fluorescence microscope. pcDNA6.2-GW/EmGFP-miR-siHIF-1α could significantly inhibit HIF-1α gene expression (P<0.05). HIF-1α and VEGF expression in the hypoxic group and siHIF-1α hypoxic group were significantly higher than normal group (P<0.05), while expression in the siHIF-1α hypoxic group was significantly lower than the hypoxic group (P<0.05). Findings suggest that HIF-1α is an important factor in the increase of bladder cancer cell permeability.

Effects of MAPKs signaling on heat stress-induced apoptosis of pulmonary microvascular endothelial cells and its mechanism / 解放军医学杂志

Objective To investigate the effect of mitogen-activated protein kinases (MAPKs) activation on the heat stressinduced apoptosis of pulmonary microvascular endothelial cells (PMVECs).Methods A mouse model of severe heat stroke was made and TUNEL and immunohistochemistry were employed to detect lung tissue damage.MACS separation was used for isolation of neonatal PMVECs,and TUNEL was utilized to detect the apoptosis of PMVECs.Western blotting was used for determining the MAPKs activation during heat stress recovery (0,2,6h).The monolayer permeability of endothelial cells was detected in terms of transmembrane resistance (TEER) and horseradish peroxidase (HRP).Cells were pretreated with MAPKs activation inhibitors to examine the effect of heat stress on the monolayer cell permeability and apoptosis.Results In mice with severe heat stroke,extensive apoptosis of PMVECs was found in their pulmonary tissues.TUNEL revealed that the number of apoptotic cells increased over time during heat stress recovery period and heat stress could activate MAPKs in PMVECs.Compared with heat stress group,in the cells pretreated with p38 or ERK activation inhibitor PD98059 and SB203580,the monolayer permeability and apoptosis increased while in cells pretreated withJNK inhibitor SP600125,the cellular permeability and apoptosis decreased.Conclusion In mice with severe heat stoke,PMVECs might experience apoptosis and p38 and ERK could inhibit apoptosis while JNK could promote apoptosis.

Effects of ADAM17 on high-glucose mediated permeability, proliferation, migration and proteins expression in human retinal microvascular endothelial cells / 眼科新进展

Objective To investigate the effects and mechanisms of a disintegrin and metalloproteinase 17 (ADAM17) on high-glucose mediated permeability,proliferation and migration in human retinal microvascular endothelial cells (HRMECs).Methods HRMECs were divided into 4 groups:normal group (5 mmol · L-1 glucose),high glucose group (25 mmol · L-1 glucose),NC (Negative control for siRNA) + high glucose group and siADAM17 (ADAM17 siRNA) + high glucose group.The expression of ADAM17 was detected using real time PCR and Western blot.Horseradish Peroxidase (HRP) was used to detect the permeability of HRMECs.Cell Counting Kit-8 (CCK-8)and BrdU were used to evaluate cell proliferation.Cell migration was determined using Transwell assay.In addition,the expression of p-EGFR,p-ERK and MMP9 was assayed using Western blot.Results Compared with normal group,the mRNA and protein levels of ADAM17 were increased in high glucose group (P ＜ 0.01).ADAM17 expression of siADAM17 + high glucose group was markedly reduced compared with NC + high glucose group.High glucose increased the permeability of HRP comparison to normal group,whereas in siADAM17 + high glucose group the permeability of HRP was reduced compared with NC + high glucose group.The optical density of HRMECs was decreased in siADAM17 + high glucose group 1.53 ± 0.29 in comparison with NC + high glucose group 2.43 ± 0.25,as well as the content of BrdU-incorporation(P ＜ 0.05).The number of migrated cells in high glucose group,NC + high glucose group,siADAM17 + high glucose group and normal group were 157.00 ± 7.93,169.00 ± 10.12,121.00 ± 9.28,110.00 ±8.25,respectively.Moreover,the expression of p-EGFR,p-ERK and MMP9 in siADAM17 +high glucose group was decreased compared with NC + high glucose group (all P ＜0.01).Conclusion SiADAM17 can reduce the cell permeability,suppressed and migration induced by high glucose via EGFR/ERK/MMP9 signaling pathway.

Mucosal Mast Cell Count Is Associated With Intestinal Permeability in Patients With Diarrhea Predominant Irritable Bowel Syndrome

BACKGROUND/AIMS: Although mucosal mast cell tryptase is known to significantly increase intestinal permeability, the relationship between mucosal mast cells and intestinal permeability remains unclear. The objective of this study was to evaluate the correlation among intestinal permeability, tryptase activity and mucosal mast cell count. METHODS: Rectal biopsies from 16 patients with diarrhea-predominant irritable bowel syndrome (IBS-D) and 7 normal subjects were assessed for tryptase activity and macromolecular permeability using horseradish peroxidase in Ussing chambers. In addition, mucosal mast cell levels were immunohistochemically quantified via image analysis. RESULTS: Rectal biopsy of tissues from IBS-D patients showed significantly increased permeability compared with those from normal controls (0.644 +/- 0.08 and 0.06 +/- 0.00 ng/2 hr/mm2, P 0.05). However, correlation analysis revealed that only mucosal mast cell count was significantly correlated with intestinal permeability in IBS-D patients (r = 0.558, P < 0.05). CONCLUSIONS: This study demonstrated a positive correlation between the number of mucosal mast cells and intestinal permeability, suggesting that mucosal mast cells play an important role for increased intestinal permeability in patients with IBS-D.

New Directions in Inflammation and Immunity: The Multi-functional Role of the Extracellular RNA/RNase System.

In the mid-eighties of the last century, extracellular-proteolipid complexes have been identified in tumor patients and circulating RNA was suggested to represent a specific secretory product of cancer cells. The presence of specific types of RNA in a variety of cancer types proved to be useful in cancer diagnosis. It has been suggested that extracellular RNA and DNA are not inert molecules, but contain biological activities. Recent data have demonstrated that extracellular RNA is likely to present the up to now undefined “natural foreign surface”, serving as an initiating factor in blood coagulation in vivo. Yet, extracellular RNA seems to have even more functions. Investigations on blood-brain-barrier have shown that extracellular RNA mediates endothelial permeability. Ample success has been achieved in administrating RNase in different animal models of vascular diseases, thereby significantly delaying thrombus formation and reducing cerebral edema formation with neuroprotection in acute stroke models. Furthermore, extracellular mammalian RNA was found to decrease tumor yield in a murine model system, suggesting that extracellular RNA might trigger immune response. Finally, extracellular nucleic acids were identified as danger signals involved in innate immunity related to neutrophil-mediated bacterial killing and haemocyte activation and coagulation in the insects. Thus, a new area of research on extracellular RNA functions with promising future perspectives just started in the field of inflammation and immunity.