Functions of HIV-1 Tat and its association with diseases / 中国生物制品学杂志

@#Acquired immune deficiency syndrome,or AIDS,has been a major infectious disease that troubles the public health in a global scale. Human immunodeficiency virus type 1(HIV-1)is the causative reagent responsible for AIDS development. Even though the highly active anti-retroviral therapy(HAART,or the cocktail therapy)that has been widely applied could effectively suppress the infection and replication of HIV-1,the infected people suffer from other related diseases,such as the HIV-associated neurocognitive disorder(HAND). This paper mainly focused on the function of an important regulatory protein of HIV-1,trans-activator of transcription(Tat),and its correlation with HIV-1 replication and HAND development,so as to clarify the importance of developing anti-AIDS drugs targeting Tat protein

Plasmin-α2-plasmin inhibitor complex and thrombin-antithrombin complex in risk stratification of massive transfusion in patients with postpartum hemorrhage / 中国输血杂志

【Objective】 To analyze the value of plasmin-α2-plasmin inhibitor complex (PIC) and thrombin-antithrombin complex (TAT) for risk stratification of massive transfusion (MT) in patients with postpartum hemorrhage (PPH). 【Methods】 Clinical data and blood samples of patients with PPH in our hospital from January 2019 to December 2022 were retrospectively analyzed. MT (MT group, n=60) was defined as transfusion of red blood cells≥10 U within 24 h after delivery, and 3.25 ng/mL and PIC level>1.04 μg/mL were independent risk factors for MT after PPH. 【Conclusion】 Elevated TAT and PIC levels are independent predictors of MT in patients with PPH, and their combined predictive efficacy is better.

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.

Research progress on mechanisms of neuroinflammation induced by methamphetamine and HIV-1 Tat protein / 中国药理学通报

Methamphetamine abuse and HIV infection are extremely serious public health and social problems facing the world today. Methamphetamine and HIV-1 Tat protein can induce neurotoxicity in an individual and synergistic way, and neuroinflammation is one of the most important mechanisms for ca-using neurotoxicity. Neuroinflammation can be mediated by glial cells, cytokines, NLRP3 inflammasomes, etc. This paper reviews the research progress of neuroinflammation induced by methamphetamine and HIV-1 Tat protein in recent years, with the aim of providing reference and basis for further exploration of the mechanisms of neuroinflammation caused by them and effective drug intervention targets in the future.

Cell-penetrating Effects and Repair of Cell Oxidative Damage of TAT-metallothionein Fusion Proteins / 中国生物化学与分子生物学报

The human Immunodeficiency Virus Transactivator (TAT) protein transduction peptide is a trans-transcription activator encoded by HIV-1. It is rich in basic amino acids, and capable of efficiently mediating the passage of exogenous macromolecules through a variety of membrane structures, such as the cytoplasmic membrane and the blood-brain barrier. Metallothionein (MT) is a protein with low molecular weights and rich cysteine contents. It plays important roles in maintaining the dynamic balance of metal contents in the body, in the detoxification of heavy metals and in defense against oxidative stress. Based on the full-length MT cDNA previously cloned from Sinopotamon henanense, we aim to prepare a TAT-mediated recombinant fusion protein that can cross the membrane and enter the cell by means of genetic engineering. The hydroxyl radical scavenging rate and total antioxidant capacity of TAT-MT were measured in vitro. An immunofluorescence technique was used to detect the transmembrane activity. An MTT assay was used to study the repair effect of H

Validity of the TAT in Brazil: Theoretical and Methodological Issues / Validade do TAT no Brasil: Questões Teóricas e Metodológicas

Abstract Although the Thematic Apperception Test (TAT) is popular in Brazil, showing evidences of its validity remains a challenge. In the present article, we discuss such issue by analyzing the definition of the TAT as a projective method and a psychological test, its use by different theoretical traditions, relations between nomothetic and idiographic analysis levels, limitations of Classical Test Theory for evaluating the instrument's properties, and challenges regarding research and practice with the instrument in Brazil. We advocate that overcoming a traditional view of projective techniques, using multidimensional methods and performing wider empirical studies on norms and validation evidences with multicenter databases may allow more secure and informed practices with the instrument among researchers and practitioners in the country.

Resumo Apesar da popularidade do Teste de Apercepção Temática (TAT) no Brasil, a demonstração de evidências de sua validade ainda permanece um desafio. No presente artigo, discutimos essa questão problematizando a definição do TAT como método projetivo e teste psicológico, abordando seu uso por diferentes correntes teóricas, relações entre os níveis nomotético e idiográfico de análise, limitações da Teoria Clássica dos Testes para avaliar suas propriedades, bem como os desafios na pesquisa e prática com o instrumento no país. Defendemos que superar a visão tradicional sobre as técnicas projetivas, utilizar métodos multidimensionais e realizar estudos empíricos mais amplos (sejam normativos ou de validação, usando bancos de dados multicêntricos) pode assegurar práticas melhor informadas com o instrumento para pesquisadores e profissionais.

Effects of TAT-SOD at Acupoints on Essential Hypertension by Monitoring Meridians Electrical Potential / 中国结合医学杂志

OBJECTIVES@#To investigate the effect on essential hypertension of the topical application of TAT-Cu, Zn-superoxide dismutase (TAT-SOD) at left acupoint Zusanli (ST 36), and to observe whether the change of electrical potential difference (EPD) can be related to the change of blood pressure.@*METHODS@#Sixteen patients with essential hypertension and 16 healthy subjects were included in the study. EPD between the left acupoints of Yanglingquan (GB 34) and Qiuxu (GB 40) was firstly screened out for the EPD detection. An intracellular superoxide quenching enzyme, TAT-SOD, was topically applied to the acupoint ST 36 within an area of 1 cm once a day, and the influence on EPD was investigated. The dosage applied to TAT-SOD group (n=8) was 0.2 mL of 3000 U/mL TAT-SOD cream prepared by adding purified TAT-SOD to a vehicle cream, while placebo group (n=8) used the vehicle cream instead. The left acupoints of Yanglingquan (GB 34) and Qiuxu (GB 40) were selected for EPD measurement after comparing EPD readings between 5 acupoints on each of all 12 meridians.@*RESULTS@#EPDs between the left acupoints of GB 34 and GB 40 for 16 patients of essential hypertension and 16 healthy subjects were 44.9±6.4 and 5.6±0.9 mV, respectively. Daily application of TAT-SOD for 15 days at ST 36 of essential hypertension patients significantly decreased systolic blood pressure (SBP) and diastolic blood pressure (DBP) of 179.6 and 81.5 mm Hg to 153.1 and 74.1 mm Hg, respectively. Responding to the change in blood pressure, EPD between the left acupoints of GB 34 and GB 40 also declined from 44.4 to 22.8 mV with the same trend. No change was observed with SBP, DBP and EPD between the left acupoints of GB 34 and GB 40 with the daily application of the placebo cream.@*CONCLUSION@#Enzymatic scavenging of the intracellular superoxide at ST 36 proved to be effective in decreasing SBP and DBP. The results reconfirm the involvement of superoxide anions and its transportation along the meridians, and demonstrate that EPD between acupoints may be an indicator to reflect its functioning status. Moreover, preliminary results suggest a close correlation between EPD and blood pressure readings, implying a possibility of using EPD as a sensitive parameter for blood pressure and to monitor the effect of antihypertensive treatment.

Twin-arginine signal peptide of Bacillus licheniformis GlmU efficiently mediated secretory expression of protein glutaminase

Background: Protein glutaminase specifically deamidates glutamine residue in protein and therefore significantly improves protein solubility and colloidal stability of protein solution. In order to improve its preparation efficiency, we exploited the possibility for its secretory expression mediated by twin-arginine translocation (Tat) pathway in Bacillus licheniformis. Results: The B. licheniformis genome-wide twin-arginine signal peptides were analyzed. Of which, eleven candidates were cloned for construction of expression vectors to mediate the expression of Chryseobacterium proteolyticum protein glutaminase (PGA). The signal peptide of GlmU was confirmed that it significantly mediated PGA secretion into media with the maximum activity of 0.16 U/ml in Bacillus subtilis WB600. A mutant GlmU-R, being replaced the third residue aspartic acid of GlmU twin-arginine signal peptide with arginine by site-directed mutagenesis, mediated the improved secretion of PGA with about 40% increased (0.23 U/ml). In B. licheniformis CBBD302, GlmU-R mediated PGA expression in active form with the maximum yield of 6.8 U/ml in a 25-l bioreactor. Conclusions: PGA can be produced and secreted efficiently in active form via Tat pathway of B. licheniformis, an alternative expression system for the industrial-scale production of PGA.

Intravenous injection of Tat-Rab GEF1 fusion protein attenuates lung injury induced by hepatic ischemia/reperfusion in mice / 中国病理生理杂志

AIM:To investigate the effect of trans-activator of transcription-Rab guanine nucleotide exchange factor 1 (Tat-RabGEF1) fusion protein by intravenous injection on hepatic ischemia/reperfusion (IR) -induced lung injury, and its underlying mechanism.METHODS:Adult male C57BL/6 rats (n=24) were randomized into 3 groups with 8 rats each:sham group, IR group, and Tat-RabGEF1 group.IR was induced by occlusion of the vessels in the hepatic pedicle for 90 min followed by 4 h of reperfusion.The Tat-RabGEF1 protein was intravenously administered right after reperfusion through the caudal vein.The levels of tumor necrosis factor-α (TNF-α) , interleukin-6 (IL-6) and interleukin-1β (IL-1β) in bronchoalveolar lavage fluid (BALF) were assessed by ELISA.The lung histopathological injury score and lung wet/dry weight ratio were evaluated, and the levels ofβ-hexosaminidase A (β-Hex A) and myeloperoxidase (MPO) in the lung tissues were also measured.The expression of tryptase in the lung was determined by Western blot.RESULTS:The pathological changes after ischemia for 90 min followed by reperfusion for 4 h were significant, along with increased lung wet/dry weight ratio and lung injury score.Intravenous injection of Tat-RabGEF1 protein effectively alleviated the lung pathological injury (P<0.05).Compared with IR group, lower levels of TNF-α, IL-6 and IL-1βin BALF, and lower expression ofβ-Hex A, MPO and tryptase in the lung tissues in Tat-RabGEF1 group were observed (P<0.05).CONCLUSION:Intravenous injection of Tat-RabGEF1 protein attenuates the lung injury after IR, and its mechanism may be related with inhibition of mast cell activation, reduced releases ofβ-Hex A and tryptase, and decreased levels of TNF-α, IL-6, IL-1βand MPO.

Transduced Tat-aldose Reductase Protects Hippocampal Neuronal Cells against Oxidative Stress-induced Damage

Aldose reductase (AR) protein, a member of the NADPH-dependent aldo-keto reductase family, reduces a wide range of aldehydes and enhances cell survival by inhibition of oxidative stress. Oxidative stress is known as one of the major pathological factor in ischemia. Since the precise function of AR protein in ischemic injury is fully unclear, we examined the function of AR protein in hippocampal neuronal (HT-22) cells and in an animal model of ischemia in this study. Cell permeable Tat-AR protein was produced by fusion of protein transduction domain in Tat for delivery into the cells. Tat-AR protein transduced into HT-22 cells and significantly inhibited cell death and regulated the mitogen-activate protein kinases (MAPKs), Bcl-2, Bax, and Caspase-3 under oxidative stress condition. In an ischemic animal model, Tat-AR protein transduced into the brain tissues through the blood-brain barrier (BBB) and drastically decreased neuronal cell death in hippocampal CA1 region. These results indicate that transduced Tat-AR protein has protective effects against oxidative stress-induced neuronal cell death in vitro and in vivo, suggesting that Tat-AR protein could be used as potential therapeutic agent in ischemic injury.

Preparation of cell penetrating peptide TAT-modified liposomes loaded with salvianolic acid B and its effect on proliferation and migration of human skin fibroblasts / 中草药

Objective To prepare the liposomes of salvianolic acid B modified with cell penetrating peptide TAT (SAB-TAT-LIP), of which has effects on preventing and treating hypertrophic scars (HS), and establish the method of quality evaluation, as well as preliminarily investigate the effect on the proliferation and migration of human skin fibroblasts (HSF). Methods Liposomes were prepared by pH gradient reverse-phase evaporation method, and the entrapment efficiency was measured by ultrafiltration. Box-Behnken design was performed to optimize the formulation of liposomes by using encapsulation rate as evaluating index. The physicochemical properties of liposomes including morphology, entrapment efficiency, particle size, zeta potential, in vitro release and transdermal absorption, and stability were studied. In addition, the effect of liposomes on proliferation of HSF was examined by MTT assay, and the effect of liposomes on migration of HSF was investigated by scratching method and Transwell assay. Results Based on the optimal formulation of SAB-TAT-LIP, the entrapment efficiency of salvianolic acid B was (86.70 ± 0.85)%, the average particle size was (219.90 ± 5.09) nm, and the zeta potential was (-9.25 ± 0.92). The in vitro 24 h cumulative release was 62.49% of the total drug with no burst effect. The in vitro 32 h cumulated skin penetration rate was 17.21%, the permeance rate was (28.33 ± 4.9) μg/(cm2∙h), and the retention volume of dermis was (44.39 ± 6.87) μg/cm2. The stability was good when placed at 4 ℃ for 10 d. The in vitro cell studies showed that SAB-TAT-LIP can significantly inhibit the proliferation, migration and invasion of human skin fibroblasts, compared with the control group (P < 0.01). Conclusion The optimized SAB-TAT-LIP have higher encapsulation efficiency, smaller particle size, good sustained release effect, and good dermal retention effect which all satisfy the in vitro release and transdermal regulation of local transdermal preparation, and it can significantly inhibit the proliferation, migration and invasion of human skin fibroblasts in vitro.

Prokaryotic expression and transmembrane transfer of fusion protein TAT-RIG-I-GFP / 生物工程学报

We studied the construction of fusion protein TAT-RIG-I-GFP prokaryotic expression vector and verified the function of TAT in transmembrane delivery. First, four pairs of specific primers were designed, and the RIG-I gene of Mallard Duck (Anas platyrhynchos) was cloned. Then, the pET-TAT-RIG-I-GFP and pET-RIG-I-GFP prokaryotic expression vectors were constructed. Meanwhile, they were converted to E. coli BL21 (DE3), which were induced to be expressed after culture. After the purification of His-60 nickel affinity chromatography column and the identification of SDS-PAGE, the purified TAT-RIG-I-GFP and RIG-I-GFP proteins were incubated to DF-1 cells. Finally, fluorescence microscopy was used to observe whether the corresponding fluorescence was produced in DF-1 cells. The results showed that pET-TAT-RIG-I-GFP fusion with TAT showed obvious green fluorescence in DF-1 cells. However, the pET-RIG-I-GFP without TAT cannot display green fluorescence. This shows that TAT-fused protein have successfully delivered DF-1 cells and play a key role in transmembrane delivery. In conclusion, these results provide a solid material basis for further study of antiviral drugs in poultry.

Effect of cell penetrating peptide TAT-modified liposomes loaded with salvianolic acid B on proliferation,migration and cell cycle of human skin fibroblasts / 中国中药杂志

Hypertrophic scar( HS) is a very common skin fibrosis disorder after human skin injury and wound healing. The objective of this study was to investigate the efficacy of cell penetrating peptide TAT-modified liposomes loaded with salvianolic acid B( SAB-TAT-LIP) on proliferation,migration and cell cycle of human skin fibroblasts( HSF),and preliminarily evaluate its effect on prevention and treatment of HS. HSF were cultured in vitro,and MTT assay was used to detect the inhibitory effect of SAB-TAT-LIP on cell proliferation. Cell migration was assessed by Transwell chamber method and scratch method; and cell cycle change was detected by flow cytometry. In vitro cell studies showed that blank liposome basically had no toxic effect on HSF. Different concentrations of SABTAT-LIP inhibited proliferation on HSF in varying degrees after intervention for different periods in a dose and time dependent manner;meanwhile,SAB-TAT-LIP significantly inhibited the migration and invasion of HSF. At the same time,SAB-TAT-LIP could block the cell cycle at G0/G1 phase after intervention for 48 h,P<0.01 as compared with the blank control group. Conclusively,our experimental data quantitatively demonstrate that SAB-TAT-LIP has significant inhibitory effect on cells proliferation,invasion and migration,with blocking effect on G0/G1 phase. This may offer a promising therapeutic strategy for transdermal delivery in prevention and treatment of HS.

Effects of HIV-1 Tat derived from central nervous system of a HIV-associated dementia patient on the activity of human umbilical vein endothelial cells / 中华实验和临床病毒学杂志

Objective@#BG-derived HIV-1 Tat protein from an HIV-associated dementia (HAD) patient was expressed in E. coli BL21(DE3) and purified in order to research the effects on human umbilical vein endothelial cells (HUVECs) activity.@*Methods@#The recombinant plasmid pGEX-KG-tat with HIV-1 tat stored in our laboratory was amplified by PCR. The PCR product was cloned into pET-32a-tat. The recombinant plasmid pET-32a-tat was transfected into E. coli, and Tat protein was expressed in BL21(DE3), which was induced by IPTG. Then it was purified by Ni-chelating chromatography column and gel filtration preloaded column, and identified by SDS-PAGE and Western blot(WB). The concentration was determined by BCA Kit. Different concentrations of Tat were added into HUVECs to detect their effects on cell activity by cck-8.@*Results@#The Tat with high purity was efficiently expressed in BL21 (DE3) and obtained by using the Ni-chelating chromatography column and gel filtration preloaded column. The concentration was 0.47 mg/ml by using BCA Kit. As the concentration of Tat increased, HUVECs activity decreased. There was no significant difference in cells viability between negative control with 100 ng/ml and 200 ng/ml group (P>0.05). There was significant difference in cells viability between negative control with 300 ng/ml, 400 ng/ml, 500 ng/ml and 1000 ng/ml group (P<0.05). But the difference between 300 ng/ml, 400 ng/ml, 500 ng/ml and 1000 ng/ml group was not statistically significant (P>0.05).@*Conclusions@#The HIV-1 Tat with biological activity was efficiently expressed in BL21 (DE3), and the activity of HUVECs was significantly decreased when the concentration reached 300 ng/ml.

Effects of human immunodeficiency virus-1 Tat protein on blood brain barrier and its mechanism / 中华实验和临床病毒学杂志

Human immunodeficiency virus-1 (HIV-1) infects the human body and acts on the related cells of blood brain barrier, causing structural and functional abnormalities of blood brain barrier, which will be beneficial to the invasion of the virus into central nervous system. There are many types of the molecular mechanism of damage of blood brain barrier. Tat protein, as HIV-1 trans-activator of transcription, can damage the vascular endothelial cells, pericytes and astrocytes, and reduce the tight junction protein expression. Some chemicals such as methamphetamine can cooperate with HIV-1 Tat protein damage blood brain barrier. In this paper, the effects and its mechanism of HIV-1 Tat protein on blood brain barrier are reviewed.

Construction of Prokaryotic Expression Vector,Expression,Purification,and Identification of Fusion Protein,TAT-RabGEF1 / 中山大学学报(医学科学版)

[Objective]To construct recombinant expression vector PET28a-TAT-RabGEF1,express,purify fusion pr-otein effectively in E.coli Rosetta(DE3),and investigate its transmembrane effect in vitro on P815 cells.[Methods]With cDNA in rats′tissues as the template,two primers containing the TAT sequence and two designed enzyme restriction cutting sites were designed. TAT-RabGEF1 fragment was amplified by PCR,and its product was inserted into PET-28a vector to construct recombinant plasmid PET28a-TAT-RabGEF1 prokaryotic expression vector. The recombinant vector was trans-formed into E.coli Rosetta(DE3)and express fusion proteins.The protein products were purified by affinity chromatography. The efficiency of the transduction of fusion protein into P815 cells were detected by immunofluorescence and analyzed by fluo-rescence spectro-photometer,with using methods of CCK-8 to analyze the cells viability after transduction of different con-centrations of fusion protein.[Results]The recombinant vector PET28a-TAT-RabGEF1 was constructed and the fusion pro-tein TAT-RabGEF1 was successfully expressed in E.coli Rosetta(DE3). By western blotting and SDS-PAGE we can see that the protein products′ relative molecular mass was about 57 ku,which was consistent with the target one,TAT-Rab-GEF1.The immunofluorescence results suggested that the fusion protein had the ability to transduct into P815 cells,and sat-uration of fusion proteins to be transducted into cells was 1 μmol/L.[Conclusion]Constructed recombinant vector PET28a-TAT-RabGEF1 and expressed fusion protein,TAT-RabGEF1,which verified the TAT′s ability of transduction. And it would build a solid technical foundation for the following research on the effect of RabGEF1′s on the activation of mast cells.

Construction, expression, purification and neuroprotective activity of TAT-FGF21 fusion protein / 中国药科大学学报

@#In order to improve the brain distribution of fibroblast growth factor 21(FGF21), TAT-FGF21 fusion protein was designed and its neuroprotective activity was investigated. The recombinant plasmid of pET28a-TAT-FGF21 was constructed and transformed into E. coli BL-21(DE3)sensitive bacteria. The TAT-FGF21 fusion protein was purified by Ni-NTA affinity chromatography column after IPTG induced expression. The SH-SY5Y cell damage model was induced by Aβ25-35, and the TAT-FGF21 fusion protein was used to intervene. The effects of Aβ25-35 and TAT-FGF21 induced on SH-SY5Y cell viability were determined using MTT method; DCFH-DA fluorescent probe was used to detect the intervention effect TAT-FGF21 on reactive oxygen species(ROS)generation induced by Aβ25-35 in SH-SY5Y cells; the effects of Aβ25-35 and TAT-FGF21 on mitochondrial membrane potential in SH-SY5Y cells were detected with JC-1 fluorescent probe. The results showed that TAT-FGF21 could improve the viability of SH-SY5Y cells, reduce the intracellular ROS production level of SH-SY5Y cells, and enhance the mitochondrial membrane potential of SH-SY5Y cells, which indicate that TAT-FGF21 could protect neurons on SH-SY5Y cell injury induced by Aβ25-35 through alleviating oxidative damage.

Tat-functionalized Ag-FeO nano-composites as tissue-penetrating vehicles for tumor magnetic targeting and drug delivery

In this paper, we prepared a dual functional system based on dextrin-coated silver nanoparticles which were further attached with iron oxide nanoparticles and cell penetrating peptide (Tat), producing Tat-modified Ag-FeO nanocomposites (Tat-FeAgNPs). To load drugs, an -SH containing linker, 3-mercaptopropanohydrazide, was designed and synthesized. It enabled the silver carriers to load and release doxorubicin (Dox) in a pH-sensitive pattern. The delivery efficiency of this system was assessed using MCF-7 cells, and using null BalB/c mice bearing MCF-7 xenograft tumors. Our results demonstrated that both Tat and externally applied magnetic field could promote cellular uptake and consequently the cytotoxicity of doxorubicin-loaded nanoparticles, with the IC of Tat-FeAgNP-Dox to be 0.63 µmol/L. The delivery efficiency of Tat-FeAgNP carrying Cy5 to the mouse tumor was analyzed using the optical imaging tests, in which Tat-FeAgNP-Cy5 yielded the most efficient accumulation in the tumor (6.7±2.4% ID of Tat-FeAgNPs). Anti-tumor assessment also demonstrated that Tat-FeAgNP-Dox displayed the most significant tumor-inhibiting effects and reduced the specific growth rate of tumor by 29.6% ( = 0.009), which could be attributed to its superior performance in tumor drug delivery in comparison with the control nanovehicles.

Preparation of PTD4-Cu,Zn-SOD fusion protein / 中华麻醉学杂志

Objective To prepare PTD4-Cu,Zn-SOD fusion protein.Methods The recombinant plasmid of pET 1 6b-Cu,Zn-SOD and pET16b-PTD4-Cu,Zn-SOD was transformed into Escherichia coli BL21 (DE3).Isopropyl β-D-1-thiogalactopyranoside was then added at a final concentration of 0.84 mmol/L,and the cells were incubated for 4 h to induce the expression of Cu,Zn-SOD and PTD4-Cu,Zn-SOD fusion protein.Lysozyme and ultrasound were used to lyse the bacteria,the supernatant was collected for 15％ SDS-PAGE to analyze the expression of the target protein.Ni-NTA His bind resin was used to purify Cu,Zn-SOD protein and PTD4-Cu,Zn-SOD fusion protein under natural conditions.Western blot was used to identify the target protein.Results The results of Western blot showed that the purity of the target protein was about 90％,and the Cu,Zn-SOD protein with a molecular weight about 19 kDa and the PTD4-Cu,Zn-SOD fusion protein with a molecular weight about 20 kDa were found.Conclusion PTD4-Cu,Zn-SOD fusion protein is prepared successfully.

Therapeutic effect of Tat-LK15-mediated the interference of siRNA with nNOS expression in the spinal dorsal horn on neuropathic pain in rats / 解放军医学杂志

Objective To investigate the therapeutic effect of cell penetrating peptide Tat-LK15 mediating small interfering RNA (siRNA) interference with the expression of neuronal nitric oxide synthase (nNOS) in rat spinal dorsal horn on neuropathic pain. Methods The transfection reagent, Tat-LK15, was used to mediate the transfection of rat spinal dorsal horn (SDH) neuronal cells with carboxyfluorescein (FAM), and then the transfection effect was observed under inverted fluorescence microscope. Fifty healthy male SD rats were randomly divided into 5 groups (n=10): control group, sham operation group (sham group), neuropathic pain group (SNL group), Tat-LK15-nNOS siRNA group (TS group) and Tat-LK15-NC siRNA group (TN group). Neuropathic pain was induced by spinal nerve ligation (SNL), rats in control group did not receive operation and only the spinal nerve was exposed in sham group. Groups SNL, TS and TN were made into the models by SNL and implanted intrathecal catheter, intrathecal administration was performed from the 7th day after model establishment, and 10μl normal saline, 10μl TS complex (including 5μg siRNA) and 10μl TN (including 5μg siRNA) were injected intrathecally each day for 7 days. Paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL) were measured at 1 day before (baseline) and 3, 7, 10 and 14 days after model establishment. Then animals were sacrificed on the 14th day after the operation and the lumbar segment (L4-6) of the spinal cord was removed to detect the expressions of nNOS mRNA and protein using q-PCR and Western blotting analysis. Results Tat-LK15 effectively mediated FAM-siRNA into SDH neuronal cells. Compared with sham group, SNL significantly decreased PWMT and PWTL and increased expressions of nNOS mRNA and protein from the 3rd day (P<0.01), but there was no significant difference between the sham and control group. Tat-LK15-nNOS siRNA complex significantly increased PWMT and PWTL and down-regulated nNOS mRNA and protein expressions in TS group compared with SNL group on the days 10 and 14. There was no significant difference between TN and SNL group. Conclusion Tat-LK15 not only can mediate successful nNOS siRNA transfection and inhibit the expression of nNOS, but also effectively relieve SNL-induced neuropathic pain in rats.