Bifunctional Au-templated RNA nanoparticles enable direct cell uptake detection and GRP75 knockdown in prostate cancer.

Nucleic acids templated on gold (Au) surfaces have led to a wide range of functional materials ranging from microarrays, sensors and probes in addition to drug delivery and treatment. In this application, we describe a simple and novel method for templating amino-functionalized RNA onto Au surfaces and their self-assembly into small, discrete nanoparticles. In our method, sample hybridization with a complementary RNA strand with and without a fatty acid (palmitamide) appendage produced functionalized double-stranded RNA on the Au surface. The resulting Au-functionalized RNA particles were found to be stable under reducing conditions according to UV-Vis spectroscopy. Sample characterization by DLS and TEM confirmed self-assembly into primarily small (∼10-40 nm) spherical shaped nanoparticles expected to be amenable to cell biology. However, fluorescence emission (λexc: 350 nm, λem: 650 nm) revealed radiative properties which limited cell uptake detection. Introduction of FITC within the Au-functionalized RNA particles produced a bifunctional probe, in which FITC fluorescence emission (λexc: 494 nm, λem: 522 nm) facilitated cell uptake detection, in a time-dependent manner. The dual encapsulation-release profiles of the FITC-labeled Au-functionalized RNA particles were validated by time-dependent UV-Vis spectroscopy and spectrofluorimetry. These experiments respectively indicated an increase in FITC absorption (λabs: 494 nm) and fluorescence emission (λem: 522 nm) with increased sample incubation times, under physiological conditions. The release of Au-functionalized siRNA particles in prostate cancer (PC-3) cells resulted in concomitant knockdown of GRP75, which led to detectable levels of cell death in the absence of a transfection vector. Thus, the formulation of stable, small and discrete Au-functionalized RNA nanoparticles may prove to be valuable bifunctional probes in the theranostic study of cancer cells.

Size Matters: Arginine-Derived Peptides Targeting the PSMA Receptor Can Efficiently Complex but Not Transfect siRNA.

Oligoarginine sequences conjugated to a short cancer-targeting peptide (CTP) selective for the prostate-specific membrane antigen (PSMA) receptor was developed for selective small interfering RNA (siRNA) delivery to a human metastatic/castration-resistant prostate cancer (PCa) cell line, which expresses PSMA on the surface. The PSMA-Rn (n = 6 and 9) peptides were synthesized by solid-phase peptide synthesis, characterized by liquid chromatography-mass spectrometry (LC-MS) and condensed with glucose-regulated protein (GRP)-silencing siRNAs. Native gels showed formation of stable CTP:siRNA ionic complexes. Furthermore, siRNA release was effected by heparin competition, supporting the peptides' capabilities to act as condensing and releasing agents. However, dynamic light scattering (DLS) and transmission electron microscopy (TEM) studies revealed large anionic complexes that were prone to aggregation and limited cell uptake for RNAi activity. Taken together, these data support the notion that the development of efficient peptide-based siRNA delivery systems is in part contingent on the formulation of discrete nanoparticles that can effectively condense and release siRNA in cells.

Direct Transfection of Fatty Acid Conjugated siRNAs and Knockdown of the Glucose-Regulated Chaperones in Prostate Cancer Cells.

The emerging field of RNAi nanotechnology has led to rapid advances in the applications of siRNAs in chemical biology, medicinal chemistry, and biotechnology. In our RNAi approach, bioconjugation of linear, V-, and Y-shaped RNA templates were designed using a series of saturated and unsaturated fatty acids to improve cell uptake and knockdown efficacy of the oncogenic glucose regulated proteins (GRPs) in prostate (PC-3) cancer cells. An optimized HCTU-coupling procedure was developed for tagging variable saturated and unsaturated fatty acids onto the 5'-ends of linear and V-shaped RNA templates that were constructed by semiautomated solid phase RNA synthesis. Hybridization and self-assembly of complementary strands yielded linear, V-, and Y-shaped fatty acid-conjugated siRNAs which were characterized by native PAGE. CD spectroscopy confirmed their A-type helix conformations. RP IP HPLC provided trends in amphiphilic properties, whereas DLS and TEM confirmed multicomponent self-assembled structures that were prone to aggregation. Subsequently, the fatty acid conjugated siRNA bioconjugates were tested for their RNAi activity by direct transfection within PC-3 cells known to overexpress oncogenic GRP activity. The siRNA bioconjugates with sense strand modifiers provided more potent GRP knockdown relative to the antisense modified siRNAs, but to a lesser extent when compared to the unconjugated siRNA controls that were transfected with the commercial Trans-IT X2 dynamic delivery system. Flow cytometry revealed that the latter may be at least in part attributed to limited cell uptake of the fatty acid conjugated siRNAs. Nonetheless, these new constructs represent an entry point in modifying higher-order siRNA constructs that may lead to the generation of more efficient siRNA bioconjugates for screening important oncogene targets and for cancer gene therapy applications.

Anatomical Changes of Full-Thickness Macular Hole Documented by Microscope-Integrated Spectral-Domain Optical Coherence Tomography.

BACKGROUND AND OBJECTIVE: To evaluate anatomical changes of idiopathic macular hole (MH) after internal limiting membrane removal and after passive suction at the hole's borders using microscope-integrated intraoperative optical coherence tomography (iOCT). PATIENTS AND METHODS: Five eyes of five subjects with full-thickness idiopathic MH underwent phacoemulsification, intraocular lens implantation, pars plana vitrectomy, and internal limiting membrane (ILM) removal. iOCT was performed after ILM removal and after passive suction at the hole's borders. RESULTS: iOCT showed decreased MH diameter after ILM removal in all cases. Passive suction achieved complete apposition of borders. All cases presented successful postsurgical closure. CONCLUSIONS: iOCT provides anatomical information during MH surgery that may impact surgical decision-making by allowing a real-time evaluation of structures. iOCT with preservative-free triamcinolone acetonide enhanced ILM visualization. Its use is superior to iOCT alone for the identification of vitreomacular interface structures. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:e105-e111.].

[Risk factors for acute kidney injury in patients treated with polymyxin B experience from 139 cases at a tertiary university hospital in Colombia]. / Factores asociados a nefrotoxicidad por polimixina B en un hospital universitario de Neiva, Colombia. 2011-2015.

BACKGROUND: The rise of infections caused by multidrug-resistant Gram negative bacilli (MDR-GNB), added to paucity of newer therapy, have led to increase polymyxin B use, despite adverse renal toxicity profile. AIM: To determine the incidence and risk factors associated to acute kidney injury (AKI) and polymyxin B use, in patients with infections caused by MDR-GNB. METHODS: A retrospective cohort, with a nested case-control study of adults who received polymyxin B for more than 48 hours at a tertiary university hospital in Colombia (2011-2015) was performed. AKI was defined by AKIN criteria. RESULTS: Of 139 patients included in our study, 102 were male with median age of 49 years (IQR:28-64). Sixty-one patients (44%) developed AKI. Independent risk factors for development of AKI included: total polymyxin B daily dose (OR = 2.19, 95% CI, 1.04-4.64); length of stay at ICU (OR = 1.03, 95% CI, 1.00-1.06); nosocomial infection (OR = 6.43, 95% CI, 2.12, -19.47); and vasopressor use (OR = 5.38, 95% CI, 2.40-12.07). Mortality was higher among AKI-patients (58.6%) compared with non-AKI patients (25.6%) (p = 0.001). CONCLUSION: In this study, the rate of AKI associated to polymyxin B use was greater than reported in studies from last decade, and associated with increased mortality. AKI associated to polymyxin B use is likely multifactorial and aggravated by the critically ill state of patients suffering nosocomial infections caused by mdr-gnb.

Factores asociados a nefrotoxicidad por polimixina B en un hospital universitario de Neiva, Colombia. 2011-2015 / Risk factors for acute kidney injury in patients treated with polymyxin B experience from 139 cases at a tertiary university hospital in Colombia

Background: The rise of infections caused by multidrug-resistant Gram negative bacilli (MDR-GNB), added to paucity of newer therapy, have led to increase polymyxin B use, despite adverse renal toxicity profile. Aim: To determine the incidence and risk factors associated to acute kidney injury (AKI) and polymyxin B use, in patients with infections caused by MDR-GNB. Methods: A retrospective cohort, with a nested case-control study of adults who received polymyxin B for more than 48 hours at a tertiary university hospital in Colombia (2011-2015) was performed. AKI was defined by AKIN criteria. Results: Of 139 patients included in our study, 102 were male with median age of 49 years (IQR:28-64). Sixty-one patients (44%) developed AKI. Independent risk factors for development of AKI included: total polymyxin B daily dose (OR = 2.19, 95% CI, 1.04-4.64); length of stay at ICU (OR = 1.03, 95% CI, 1.00-1.06); nosocomial infection (OR = 6.43, 95% CI, 2.12, -19.47); and vasopressor use (OR = 5.38, 95% CI, 2.40-12.07). Mortality was higher among AKI-patients (58.6%) compared with non-AKI patients (25.6%) (p = 0.001). Conclusion: In this study, the rate of AKI associated to polymyxin B use was greater than reported in studies from last decade, and associated with increased mortality. AKI associated to polymyxin B use is likely multifactorial and aggravated by the critically ill state of patients suffering nosocomial infections caused by mdr-gnb.

Introducción: El surgimiento de infecciones graves causadas por bacilos gramnegativos multi-resistentes (BGN-MR), sumado a la carencia de nuevas opciones terapéuticas efectivas, ha llevado a retomar el uso de polimixina B, a pesar de su perfil de nefrotoxicidad. Objetivo: Determinar la incidencia y factores relacionados con el desarrollo de nefrotoxicidad asociada al uso de polimixina B, en pacientes adultos con infecciones causadas por BGN-MR. Materiales y Métodos: Estudio observacional, analítico, tipo cohorte histórica, con un análisis de casos y controles anidado, realizado en un hospital universitario de tercer nivel de Colombia entre 2011 y 2015, en pacientes que recibieron polimixina B intravenosa por más de 48 h. Resultados: De 139 pacientes incluidos en el estudio, 61 (44%) desarrollaron falla renal aguda por criterios AKIN. Los factores de riesgo independientes para nefrotoxicidad fueron: dosis diaria de polimixina B (OR 2,19; IC 95% 1,04-4,64), días de estancia en UCI (OR 1,03; IC 95% 1,00-1,06), presencia de infección nosocomial (OR 6,43; IC 95% 2,12-19,47) y requerimiento de fármacos vasopresores (OR 5,38; IC 95%: 2,40-12,07). Conclusión: La tasa de nefrotoxicidad observada en pacientes que recibieron polimixina B es considerable; su origen probablemente multifactorial y agravada por estado crítico de pacientes con infecciones nosocomiales por BGN-MR.

Antibiotic prophylaxis and its appropriate timing for urological surgical procedures in patients with asymptomatic bacteriuria: A systematic review.

OBJECTIVE: To review the existing literature on when and how to treat patients with asymptomatic bacteriuria (AB) who undergo urological surgery, as uncertainty about this issue persists. METHODS: A systematic review was conducted to compare the different timing of administration of antibiotic prophylaxis in patients with AB undergoing urological surgery. We used predefined inclusion and exclusion criteria, and we also developed a specific quality scale to assess the quality of the papers included. RESULTS: Nine studies met the inclusion criteria. Of the nine studies included, eight evaluated antibiotic prophylaxis regardless of the presence of AB, as their purpose was to evaluate the effectiveness of antibiotic prophylaxis for urological procedures. Of these, four studies showed a significant reduction in the rate of infections in the intervention group compared with placebo, or with the same antibiotic therapy but using different durations of therapy. Four studies found no significant differences in infectious complications between the intervention and comparison arms. Only one study assessed the duration of antibiotic prophylaxis in patients with AB. CONCLUSIONS: With the available evidence, antibiotic therapy should be considered only for procedures in which studies have shown a clinical benefit in the prevention of infection. It is important to establish the duration and type of treatment for antimicrobial therapy for surgical prophylaxis in patients with AB who are going to receive urological invasive procedures.

Spitzenkorper localization and intracellular traffic of green fluorescent protein-labeled CHS-3 and CHS-6 chitin synthases in living hyphae of Neurospora crassa.

The subcellular location and traffic of two selected chitin synthases (CHS) from Neurospora crassa, CHS-3 and CHS-6, labeled with green fluorescent protein (GFP), were studied by high-resolution confocal laser scanning microscopy. While we found some differences in the overall distribution patterns and appearances of CHS-3-GFP and CHS-6-GFP, most features were similar and were observed consistently. At the hyphal apex, fluorescence congregated into a conspicuous single body corresponding to the location of the Spitzenkörper (Spk). In distal regions (beyond 40 microm from the apex), CHS-GFP revealed a network of large endomembranous compartments that was predominantly comprised of irregular tubular shapes, while some compartments were distinctly spherical. In the distal subapex (20 to 40 microm from the apex), fluorescence was observed in globular bodies that appeared to disintegrate into vesicles as they advanced forward until reaching the proximal subapex (5 to 20 microm from the apex). CHS-GFP was also conspicuously found delineating developing septa. Analysis of fluorescence recovery after photobleaching suggested that the fluorescence of the Spk originated from the advancing population of microvesicles (chitosomes) in the subapex. The inability of brefeldin A to interfere with the traffic of CHS-containing microvesicles and the lack of colocalization of CHS-GFP with the endoplasmic reticulum (ER)-Golgi body fluorescent dyes lend support to the idea that CHS proteins are delivered to the cell surface via an alternative route distinct from the classical ER-Golgi body secretory pathway.