Cell membrane-camouflaged PLGA biomimetic system for diverse biomedical application

The emerging cell membrane (CM)-camouflaged poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) (CM@PLGA NPs) have witnessed tremendous developments since coming to the limelight. Donning a novel membrane coat on traditional PLGA carriers enables combining the strengths of PLGA with cell-like behavior, including inherently interacting with the surrounding environment. Thereby, the in vivo defects of PLGA (such as drug leakage and poor specific distribution) can be overcome, its therapeutic potential can be amplified, and additional novel functions beyond drug delivery can be conferred. To elucidate the development and promote the clinical transformation of CM@PLGA NPs, the commonly used anucleate and eukaryotic CMs have been described first. Then, CM engineering strategies, such as genetic and nongenetic engineering methods and hybrid membrane technology, have been discussed. The reviewed CM engineering technologies are expected to enrich the functions of CM@PLGA for diverse therapeutic purposes. Third, this article highlights the therapeutic and diagnostic applications and action mechanisms of PLGA biomimetic systems for cancer, cardiovascular diseases, virus infection, and eye diseases. Finally, future expectations and challenges are spotlighted in the concept of translational medicine.     

Lack of intestinal transport of [3H]-demethylphalloin: Comparative studies with phallotoxins and bile acids on isolated small intestinal cells and ileal brush border membrane vesicles

Summary Several earlier studies suggested that the uptake of phallotoxins by liver cells is a carrier mediated process using a transport system normally handling bile acids (see Frimmer 1982). In this study we have shown whether ileal cells, well known to transport bile acids too, are able to take up phallotoxins. Isolated epithelial cells prepared from guinea pig ileum accumulated [¹⁴C]-cholate, whereas [³H]-demethylphalloin ([³H]-DMP) was not taken up. The same observation was made with isolated jejunal cells but the uptake of [¹⁴C]-cholate was much slower. [³H]-DMP, however, was partly bound to intestinal cells. This process was not inhibited by cholate, iodipamide, oligomycin and carbonylcyano-chlorophenylhydrazone (CCCP), compounds known to decrease the uptake of phallotoxins into liver cells. Substituting Na⁺ for choline⁺ and also Cl^– for SCN^– did not influence the binding of [³H]-DMP. Frozen intestinal cells from the guinea pig bound two times more [³H]-DMP after thawing compared with intact cells. Supplementary uptake experiments on isolated brush border membrane vesicles from rat ileum revealed that phalloidin does not inhibit taurocholate uptake and that taurocholate does not interfer with [³H]-DMP binding.The results suggest that [³H]-demethylphalloin is not recognized by the bile acid carrier of the guinea pig and the rat ileum. It is concluded that the transport system for bile acids present in ileal cells is different from that of liver cells.Abbreviations TC taurocholic acid - DMP demethylphalloin - CCCP carbonylcyano-chlorophenylhydrazone - EGTA ethylene-glycol-bis-(2-aminoethylether)-N,N-tetraacetic acid - FCCP carbonylcyano-p-trifluoromethoxyphenylhydrazine This work was supported by the Deutsche Forschungsgemeinschaft     

Polymer hydration and stiffness at biointerfaces and related cellular processes

The direct and indirect (by changing mechanical properties) effects of hydration at interfaces on cellular processes and tissue diseases are reviewed. The essential effect of substrate stiffness on cellular processes was demonstrated in the last decade. The combined effect of surface stiffness and hydration at interfaces has garnered much less attention, though hydration and dehydration play important roles in biological processes. This review focuses on the studies that demonstrate how hydration affects biological processes at interfaces. Elevated sodium and dehydration stimulate inflammatory signaling in endothelial cells and promote atherosclerosis. Various types of implant and blood contacting device coatings with varied surface stiffness and hydration have been reported. Effect of hydration on polymer modulus of elasticity and viscoelasticity was discussed taking into account cells adhesion, migration, proliferation, differentiation on surfaces with various degree of hydration. Future directions of research were considered, including the use of nanotechnology to regulate the hydration degree.     

氧化应激条件下miR-21对人眼小梁网细胞胞外基质蛋白表达的影响

目的 探讨氧化应激条件下miR-21对人眼小梁网细胞(human trabecular meshwork cells,HTMCs)胞外基质蛋白表达的影响.方法 用不同浓度H2O2(0μmol·L-1、200 μmol·L-1、400 μmol·L-1、600 μmol·L-1)刺激HTMCs l h,MTT法检测其对HTMCs活力的影响,从而确定后续实验所需H2O2浓度.随后将细胞分成正常组和H2O2组,Real-time PCR检测miR-21的表达,Western blot检测胞外基质蛋白(纤维连接蛋白和胶原蛋白I)的表达.然后将细胞分成5组:H2O2组(只用H2O2处理)、miR-21干预组(H2O2+ miR-21模拟物)、miR-21对照组(H2O2+ miR-21对照模拟物)、miR-21抑制组(H2O2+ miR-21抑制剂)和miR-21抑制对照组(H2O2+miR-21抑制剂对照物),Real-time PCR检测miR-21、转化生长因子(transforming growth factor,TGF)-β2和PTEN mRNA表达,Western blot检测胞外基质蛋白、TGF-β2和PTEN蛋白表达.最后将细胞分成3组:H2O2组(只用H2O2处理)、PTEN干扰组(H2O2 +PTEN siRNA)和干扰对照组(H2O2+ control siRNA),检测PTEN、胞外基质蛋白和TGF-β2蛋白水平表达.结果 当H2O2浓度≥400 μmol·L-1时,可显著抑制HTMCs的活性,后续实验选择此浓度.与正常组相比,H2O2组中miR-21、纤维连接蛋白和胶原蛋白Ⅰ的表达均增加,差异均有统计学意义(均为P＜0.05).检测氧化应激条件下miR-21对胞外基质蛋白、TGF-β2和PTEN表达的影响,发现与H2 O2组相比,miR-21对照组和miR-21抑制对照组中miR-21、纤维连接蛋白与胶原蛋白Ⅰ蛋白水平表达以及TGF-β2和PTEN mRNA及蛋白水平表达差异均无统计学意义(均为P＞0.05);与miR-21对照组相比,miR-21干预组miR-21、纤维连接蛋白和胶原蛋白Ⅰ蛋白水平及TGF-β2 mRNA和蛋白水平表达均增加,PTEN蛋白水平表达降低,差异均有统计学意义(均为P＜0.05),而PTEN mRNA表达差异均无统计学意义(均为P＞0.05);与miR-21抑制对照组相比,miR-21抑制组miR-21、纤维连接蛋白和胶原蛋白Ⅰ蛋白水平及TGF-β2 mRNA和蛋白水平表达均降低,PTEN蛋白水平表达增加,差异均有统计学意义(均为P＜O.05),而PTEN mRNA水平差异无统计学意义(P＞0.05).采用Western blot检测氧化应激条件下PTEN对TGF-β2和胞外基质蛋白表达的影响,发现与H2O2组相比,干扰对照组PTEN、TGF-β2、纤维连接蛋白和胶原蛋白Ⅰ的表达差异均无统计学意义(均为P＞0.05);与干扰对照组相比,PTEN干扰组PTEN的表达下调,TGF-β2、纤维连接蛋白和胶原蛋白Ⅰ的表达均升高,差异均有统计学意义(均为P＜0.05).结论 氧化应激条件下miR-21可增加HTMCs胞外基质产物,这可能与其靶向沉默PTEN基因,调节TGF-β2的表达相关.     

沉默GOLPH3基因表达逆转人结肠癌细胞顺铂耐药的研究

背景与目的：化疗是结肠癌的重要治疗方法之一,其方案常含有铂类药物,而化疗耐药会影响结肠癌疗效和预后,其发生机制与基因异常表达有关。高尔基磷酸化蛋白3（Golgi phosphoprotein 3,GOLPH3）是一个癌基因,在结肠癌组织中存在过表达,可促进结肠癌细胞的增殖,与预后不良相关。目前,GOLPH3基因的高表达与结肠癌对铂类耐药的相关性尚不明确。探讨沉默GOLPH3基因逆转人结肠癌HT29细胞对顺铂的化疗耐药效应和机制。方法：HT29细胞分为5组。① 对照组：人结肠癌HT29细胞;② 转染组：siRNA-GOLPH3转染HT29细胞;③ 实验组1：经顺铂处理的HT29细胞;④ 实验组2：经顺铂处理的siRNA-GOLPH3转染HT29细胞;⑤ 实验组3：经顺铂和细胞外调节蛋白激酶（extracellular signal-regulated protein kinases,ERK）1/2抑制剂PD98059处理的HT29细胞。四甲基偶氮唑蓝（methyl thiazolyl tetrazolium,MTT）法、平板克隆形成实验检测各组结肠癌HT29细胞增殖及克隆形成能力。蛋白质印迹法（Western blot）检测GOLPH3、P-糖蛋白（P-glycoprotein,P-gp）、ERK1/2和pERK1/2蛋白的表达。结果：经顺铂处理后,实验组1、实验组2的细胞在波长490 nm处的吸光度（D）值均显著低于对照组（P<0.05）,实验组2的D₄₉₀值显著低于实验组1（P<0.001）;实验组1和实验组2的细胞集落数均显著低于对照组（P<0.01）,实验组2的细胞集落数显著低于实验组1（P<0.001）。实验组1的P-gp、GOLPH3、pERK1/2蛋白表达量显著高于实验组2（P<0.01）;实验组3的P-gp蛋白表达量较实验组1显著降低（P<0.01）。结论：沉默GOLPH3基因可通过抑制丝裂原活化蛋白激酶/细胞外信号调节激酶（mitogen-activated protein kinase/extracellular signal-regulated kinase,MAPK/ERK）信号通路逆转HT29结肠癌细胞对顺铂化疗的耐药性。     

Effect of traditional Chinese medicine Shu-Mai-Tang on attenuating TNFalpha-induced myocardial fibrosis in myocardial ischemia rats

Shu-Mai-Tang (SMT) is a traditional Chinese medicine for treatment of ischemic heart disease. The effect of SMT on inflammation-induced myocardial fibrosis, left ventricular (LV) remodeling, and the potential mechanism in myocardial ischemia (MI) rats were investigated. Rats with ligated left anterior descending coronary artery (MI model) were randomly divided into three groups (SMTL, SMTH, and MIR). A group undergoing Sham operation (Sham; n=16) was also included. SMT (342 or 1710 mg/kg for SMTL or SMTH groups, respectively) was orally administered daily for 1 and 6 weeks. Cardiac function, myocardial fibrosis, serum tumor necrosis factor-alpha (TNFalpha) concentration, the cardiac expressions of phosphorylated p38 MAPK and tissue inhibitor of matrix metalloproteinase (TIMP)-1 and TNFalpha were examined by echocardiography, histological staining, radioimmunoassay, western blot, respectively. In the present study, significant reduced myocardial fibrosis, as well as decreased phospho-p38 MAPK, TIMP-1, and TNFalpha proteins, and serum TNFalpha level, accompanied by improved cardiac function in the SMT-treated rats in a dose-dependent manner as compared with the MIR. These results suggested that SMT could anti-inflammation-induced myocardial fibrosis and reverse LV remodeling in MI rats, and the mechanism may be related to the effect of SMT on inhibiting p38 MAPK signaling pathway.     

Circulating platelet‐derived extracellular vesicles correlate with night‐time blood pressure and vascular organ damage and may represent an integrative biomarker of vascular health

Elevated office blood pressure (BP) has previously been associated with increased levels of circulating extracellular vesicles (EVs). The present study aimed to assess the relationship between levels of platelet derived EVs, ambulatory BP parameters, and pulse wave velocity as a marker of macrovascular organ damage. A total of 96 participants were included in the study. Platelet‐derived extracellular vesicles (pEVs) were evaluated by flow cytometry (CD41+/Annexin v+). BP evaluation included unobserved automated office BP and ambulatory BP monitoring. Carotid‐femoral pulse wave velocity (PWV) was measured as a marker of macrovascular damage. pEVs correlated with nocturnal systolic BP (r = 0.31; p = .003) and nocturnal dipping (r = ‐0.29; p = .01) in univariable analysis. Multivariable regression models confirmed robustness of the association of EVs and nocturnal blood pressure (p = .02). In contrast, systolic office, 24h‐ and daytime‐BP did not show significant associations with pEVs. No correlations were found with diastolic BP. Circulating pEVs correlated with pulse wave velocity (r = 0.25; p = .02). When comparing different hypertensive phenotypes, higher levels of EVs and PWV were evident in patients with sustained hypertension compared to patients with white coat HTN and healthy persons. Circulating platelet derived EVs were associated with nocturnal BP, dipping, and PWV. Given that average nocturnal BP is the strongest predictor of CV events, platelet derived EVs may serve as an integrative marker of vascular health, a proposition that requires testing in prospective clinical trials.     

兔结膜重建中羊膜细胞外基质、保存羊膜及自体结膜的比较

目的:研究羊膜细胞外基质(amnion extracellular matrix,AECM)在兔结膜重建中的作用.方法:将36只新西兰白兔随机分为3组,均右眼实施手术,羊膜细胞外基质(AECM)组12眼,保存羊膜(frozen amnion membrane,FZAM)组12眼,自体结膜(autologous conjunctiva,AC)组12眼.术后对各组进行密切的跟踪观察,分别在术后1,2,4,8wk对术眼行印迹细胞学及病理学检查.结果:所有术眼均愈合良好,无瘢痕化及睑球粘连等并发症.术后2wk FZAM、AC组炎症细胞浸润高于AECM组,AECM溶解时间长于FZAM.杯状细胞分化方面:术后2wk,AECM组与AC组比较无统计学差异(P＞0.05);FZAM组与AECM、AC组比较统计学差异显著(FZAM组vsAECM组P＜0.01,FZAM组vsAC组P＜0.01).术后4,8wk,3组比较均有统计学差异(FZAM组vs AECM组P＜0.05,FZAM组vs AC组P＜0.05,AC组vs AECM组P＜0.05).结论:羊膜细胞外基质和保存羊膜作为结膜替代物有效,而羊膜细胞外基质比保存羊膜有更长的存活周期,自体结膜是修复结膜缺损最理想的替代物.     

Brief Report: Highly motile cells are metabolically responsive to collagen density

Altered tissue mechanics and metabolism have gained significant attention as drivers of tumorigenesis, and mechanoresponsive metabolism has been implicated in migration and metastasis. However, heterogeneity in cell populations makes it difficult to link changes in behavior with metabolism, as individual cell behaviors are not necessarily reflected in population-based measurements. As such, the impact of increased collagen deposition, a tumor-associated collagen signature, on metabolism remains ambiguous. Here, we utilize a wide range of collagen densities to alter migration ability and study the bioenergetics of individual cells over time. Sorting cells based on their level of motility revealed energetics are a function of collagen density only for highly motile cells, not the entire population or cells with low motility. Changes in migration with increasing collagen density were correlated with cellular energetics, where matrix conditions most permissive to migration required less energy usage during movement and migrated more efficiently. These findings reveal a link between matrix mechanics, migratory phenotype, and bioenergetics and suggest that energetic costs are determined by the extracellular matrix and influence cell motility.