Research and Application of Nanozymes in Disease Treatment / 生物化学与生物物理进展

Nanozyme is novel nanoparticle with enzyme-like activity, which can be classified into peroxidase-like nanozyme, catalase-like nanozyme, superoxide dismutase-like nanozyme, oxidase-like nanozyme and hydrolase-like nanozyme according to the type of reaction they catalyze. Since researchers first discovered Fe3O4 nanoparticles with peroxidase-like activity in 2007, a variety of nanoparticles have been successively found to have catalytic activity and applied in bioassays, inflammation control, antioxidant damage and tumor therapy, playing a key role in disease diagnosis and treatment. We summarize the use of nanozymes with different classes of enzymatic activity in the diagnosis and treatment of diseases and describe the main factors influencing nanozyme activity. A Mn-based peroxidase-like nanozyme that induces the reduction of glutathione in tumors to produce glutathione disulfide and Mn2+, which induces the production of reative oxygen species (ROS) in tumor cells by breaking down H2O2 in physiological media through Fenton-like action, thereby inhibiting tumor cell growth. To address the limitation of tumor tissue hypoxia during photodynamic tumor therapy, the effect of photodynamic therapy is significantly enhanced by using hydrogen peroxide nanozymes to catalyze the production of oxygen from H2O2. In pathological states, where excess superoxide radicals are produced in the body, superoxide dismutase-like nanozymes are able to selectively regulate intracellular ROS levels, thereby protecting normal cells and slowing down the degradation of cellular function. Based on this principle, an engineered nanosponge has been designed to rapidly scavenge free radicals and deliver oxygen in time to save nerve cells before thrombolysis. Starvation therapy, in which glucose oxidase catalyzes the hydrolysis of glucose to gluconic acid and hydrogen peroxide in cancer cells with the involvement of oxygen, attenuates glycolysis and the production of intermediate metabolites such as nucleotides, lipids and amino acids, was used to synthesize an oxidase-like nanozyme that achieved effective inhibition of tumor growth. Furthermore, by fine-tuning the Lewis acidity of the metal cluster to improve the intrinsic activity of the hydrolase nanozyme and providing a shortened ligand length to increase the density of its active site, a hydrolase-like nanozyme was successfully synthesized that is capable of cleaving phosphate bonds, amide bonds, glycosidic bonds and even biofilms with high efficiency in hydrolyzing the substrate. All these effects depend on the size, morphology, composition, surface modification and environmental media of the nanozyme, which are important aspects to consider in order to improve the catalytic efficiency of the nanozyme and have important implications for the development of nanozyme. Although some progress has been made in the research of nanozymes in disease treatment and diagnosis, there are still some problems, for example, the catalytic rate of nanozymes is still difficult to reach the level of natural enzymes in vivo, and the toxic effects of some heavy metal nanozymes material itself. Therefore, the construction of nanozyme systems with multiple functions, good biocompatibility and high targeting efficiency, and their large-scale application in diagnosis and treatment is still an urgent problem to be solved. (1) To improve the selectivity and specificity of nanozymes. By using antibody coupling, the nanoparticles are able to specifically bind to antigens that are overexpressed in certain cancer cells. It also significantly improves cellular internalization through antigen-mediated endocytosis and enhances the enrichment of nanozymes in target tissues, thereby improving targeting during tumor therapy. Some exogenous stimuli such as laser and ultrasound are used as triggers to control the activation of nanozymes and achieve specific activation of nanozyme. (2) To explore more practical and safer nanozymes and their catalytic mechanisms: biocompatible, clinically proven material molecules can be used for the synthesis of nanoparticles. (3) To solve the problem of its standardization and promote the large-scale clinical application of nanozymes in biomonitoring. Thus, it can go out of the laboratory and face the market to serve human health in more fields, which is one of the future trends of nanozyme development.

Determination of purity of a new anti-fatty liver drug IMH by differential scanning calorimetry method and uncertainty evaluation / 药学学报

The purity of 4,4′-dimethoxy-5,6,5′,6′-bis (methylenedioxy)-2′-morpholine methylenebiphenyl-2-methyl formate methanesulfonate (IMH), a new drug for fatty liver treatment, was determined through differential scanning calorimetry (DSC). Analysis of two-factor non repeatability method was performed in the investigation the effects of two factors (heating rate and sample weight) on purity determination. The DSC experimental parameters were optimized as follows: heating rate was 10 ℃·min-1, temperature range was 150-300 ℃, sample weight was 2.0-4.1 mg, and N2 flow rate was 80 mL·min-1. The linear correlation coefficient (r) of this DSC method was 0.999 8. The RSD value (n = 6) of precision was 0.03%. The standard value and uncertainty of the purity results of the multiple batches of IMH drugs were (99.74 ± 0.29)%, (99.91 ± 0.28)%, (99.90 ± 0.28)%, and (99.81 ± 0.28)% with inclusion factor (K) of 2 and confidence probability (P) of 0.95. The results were basically consistent with the results of the mass balance method. The DSC mehod is a simple, rapid and accurate method, and provides a new reference method for determining the purity of IMH drugs, improves the accuracy and reliability of purity determination.

Expression of E2F1 Gene in Acute Leukemia and Its Clinical Significance / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the expression of E2F1 gene in patients with acute leukemia(AL) and its clinical significance.</p><p><b>METHODS</b>Seventy-two AL patients treated in March 2015 -March 2016 in our hospital were selected, and 24 healthy people were selected as controls. RT-PCR and Western blot were applied to determine the level of E2F1 gene transcription and expression, and the statistical analysis was performed to reveal the clinical value of E2F1 gene.</p><p><b>RESULTS</b>The relative expression levels of E2F1 gene and protein in bone marrow of AL patients was higher than that in control group (P<0.05). The levels of WBC, β-MG and LDH in the patients with high expression of E2F1 gene were higher than those in patients with low expression of E2F1 gene(P<0.05), but the E2F1 gene expression did not correlate with sex, fever, fatigue, bone marrow blast ratio, peripheral blood blasts ratio (P>0.05). The complete remission (CR) of patients with low expression of E2F1 was significantly higher than that of patients with high expression of E2F1(P<0.05). And the drug resistance in the patients with low expression of E2F1 gene was lower than that of patients with high expression of E2F1 gene (P<0.05). The expression level of E2F1 gene decreased significantly in patients with symptomatic remission after treatment (P<0.05). The expression levels of E2F1 gene in M1, M2 and M5 patients decreased significantly after treatment (P<0.05). Kaplan-Meier survival analysis showed that OS and DFS in the patients with low expression of E2F1 gene were higher than those in patients with high expression (P<0.05). Multivariate Cox regression analysis showed that the age and E2F1 gene were the independent influencing factors of OS (P<0.05); the sex and E2F1 gene were the dependent factors of DFS (P<0.05).</p><p><b>CONCLUSION</b>The expression level of E2F1 gene in patients with AL has been found to be higher, the higher level of E2F1 gene closely relates with AL patients, E2F1 gene can be used as a biological target for the clinical treatment of AL.</p>

Role of valsartan on myocardial Calpain I, calcineurin and Ca/calmodulin-dependent protein kinase IIδ expression of renovascular hypertensive rats / 中华心血管病杂志

<p><b>OBJECTIVE</b>To determine the protein expression of Calpain I, mRNA and protein expressions and activity of calcineurin, and the alternative splicing of Ca/calmodulin-dependent protein kinase II (CaMKII) δ in the hypertrophic heart, and to investigate the effect of angiotensin II type 1 receptor blocker valsartan (Val) on cardiac hypertrophy and the level of Calpain I, calcineurin and CaMKIIδ in renovascular hypertensive rats model.</p><p><b>METHODS</b>Rats were randomly divided into sham-operated control (n=8), hypertension (n=8) and hypertension plus Val (n=8, 30 mg×kg(-1)×(-1)). The renovascular hypertension was induced by two kidney-one clip methods in rats. The ratio of left ventricular weight to body weight was measured, the mRNA expression of calcineurin and alternative splicing of CaMKIIδ were determined by RT-PCR, the protein expression of Calpain I and calcineurin were measured by Western blot and the activity of calcineurin activity was assayed by a specialized kit.</p><p><b>RESULTS</b>Eight weeks after procedure, hypertension rats developed significantly cardiac hypertrophy, and the protein expression of Calpain I, mRNA and protein expression and the activity of calcineurin were significantly increased compared sham-operated control rats (all P<0.01), the mRNA expression of CaMKIIδA and B increased, CaMKIIδC mRNA decreased (P<0.01). Treatment with valsartan effectively attenuated cardiac hypertrophy and reversed hypertension induced changes on myocardial Calpain I, calcineurin and CaMKIIδ.</p><p><b>CONCLUSION</b>Valsartan attenuates cardiac hypertrophy in renovascular hypertensive rats, possibly through inhibiting Calpain I, calcineurin and CaMKIIδ signaling pathways.</p>

Effect of atorvastatin on ACE2 expression in pressure overload induced cardiac hypertrophy in rats / 中南大学学报(医学版)

OBJECTIVE@#To investigate the effect of atorvastatin on the expression of angiotensin converting enzyme 2 (ACE2) mRNA and its protein in hypertrophic myocardium in rats.@*METHODS@#Suprarenal abdominal aortic coarctation was performed to create the pressure overload induced left ventricular hypertrophy model in rats.@*RESULTS@#Rats were randomly divided into 5 groups: (1) normal control group (Group A); (2) normal control group treated with atorvastatin [(5 mg/(kg.dd), Group B]; (3) sham group (Group C); (4) atorvastatin given orally by gastric gavage for 4 weeks [5 mg/(kg.dd),Group D]; (5) vehicle group (Group E). Stained pathological section was observed under light microscope to measure cardiomyocyte diameter transversa and collagen volume fraction. ACE2 mRNA and its protein expression were detected by real-time RT-PCR and Western blot. Compared with Group A,B, and C, the left ventricular mass index, cardiomyocyte diameter transversa and collagen volume fraction in Group E increased statistically (P< 0.01), ACE2 mRNA and its protein expression also elevated remarkably (P< 0.01). Compared with Group E, the above mentioned indexes in Group D reduced significantly (P< 0.01).@*CONCLUSION@#ACE2 mRNA and its protein expression increase significantly in hypertrophic myocardium in rats; atorvastatin can attenuate cardiac hypertrophy due to pressure overload in rats effectively, and part of this anti-hypertrophy effect may be attributed to decrease ACE2 mRNA and protein expression.