Nanoarchitectonic Engineering of Thermal-Responsive Magnetic Nanorobot Collectives for Intracranial Aneurysm Therapy

Stent-assisted coiling is a main treatment modality for intracranial aneurysms (IAs) in clinics, but critical challenges remain to be overcome, such as exogenous implant-induced stenosis and reliance on antiplatelet agents. Herein, we report an endovascular approach for IA therapy without stent grafting or microcatheter shaping, enabled by active delivery of thrombin (Th) to target aneurysms using innovative phase-change material (PCM)-coated magnetite-thrombin (Fe3O4-Th@PCM) FTP nanorobots. The nanorobots are controlled by an integrated actuation system of dynamic torque-force hybrid magnetic fields. With robust intravascular navigation guided by real-time ultrasound imaging, nanorobotic collectives can effectively accumulate and retain in model aneurysms constructed in vivo, followed by controlled release of the encapsulated Th for rapid occlusion of the aneurysm upon melting the protective PCM (thermally responsive in a tunable manner) through focused magnetic hyperthermia. Complete and stable aneurysm embolization was confirmed by postoperative examination and 2-week postembolization follow-up using digital subtraction angiography (DSA), contrast-enhanced ultrasound (CEUS) and histological analysis. The safety of the embolization therapy was assessed through biocompatibility evaluation and histopathology assays. Our strategy, seamlessly integrating secure drug packaging, agile magnetic actuation and clinical interventional imaging, avoids possible exogenous implant rejection, circumvents cumbersome microcatheter shaping, and offers a promising option for IA therapy

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

A DFT Study on the Conversion of Aryl Iodides to Alkyl Iodides: Reductive Elimination of R-I from Alkylpalladium Iodide Complexes with Accessible -Hydrogens

DFT calculations have been performed on the palladium-catalyzed carboiodination reaction. The reaction involves oxidative addition, alkyne insertion, C-N bond cleavage, and reductive elimination. For the alkylpalladium iodide intermediate, LiOtBu stabilizes the intermediate in non-polar solvents, thus promoting reductive elimination and preventing -hydride elimination. The C-N bond cleavage process was explored and the computations show that PPh3 is not bound to the Pd center during this step. Experimentally, it was demonstrated that LiOtBu is not necessary for the oxidative addition, alkyne insertion, or C-N bond cleavage steps, lending support to the conclusions from the DFT calculations. The turnover-limiting steps were found to be C-N bond cleavage and reductive elimination, whereas oxidative addition, alkyne insertion, and formation of the indole ring provide the driving force for the reaction

A Novel Radioligand Reveals Tissue Specific Pharmacological Modulation of Glucocorticoid Receptor Expression with Positron Emission Tomography.

The complexity of glucocorticoid receptor (GR) signaling cannot be measured with direct tissue analysis in living subjects, which has stifled our understanding of GR's role in human physiology or disease and impeded the development of selective GR modulators. Herein, we report 18F-5-(4-fluorobenzyl)-10-methoxy-2,2,4-trimethyl-2,5-dihydro-1H-chromeno[3,4-f]quinoline (18F-YJH08), a radioligand that enables noninvasive measurements of tissue autonomous GR expression levels in vivo with positron emission tomography (PET). YJH08 potently binds GR (Ki ∼ 0.4 nM) with ∼100-fold selectivity compared to nuclear hormone receptors in the same subfamily. 18F-YJH08 was prepared via Cu(OTf)2(py)4-mediated radiofluorination of an arylboronic acid pinacol ester with ∼12% decay corrected radiochemical yield from the starting 18F-fluoride ion. We applied treatment with the tissue-wide GR agonist dexamethasone and adrenalectomy and generated an adipocyte specific GR knockout mouse to show that 18F-YJH08 specifically binds GR in normal mouse tissues, including those for which aberrant GR expression is thought to drive severe diseases (e.g., brain, adipose tissue, kidneys). Remarkably, 18F-YJH08 PET also revealed that JG231, a potent and bioavailable HSP70 inhibitor, selectively degrades GR only in the adipose tissue of mice, a finding that foreshadows how GR targeted PET might be integrated into drug discovery to screen for selective GR modulation at the tissue level, beyond the historical screening that was performed at the transcriptional level. In summary, 18F-YJH08 enables a quantitative assessment of GR expression levels in real time among multiple tissues simultaneously, and this technology is a first step toward unraveling the daunting complexity of GR signaling and rationally engineering tissue specific therapeutic modulators in vivo

A Novel Radioligand Reveals Tissue Specific Pharmacological Modulation of Glucocorticoid Receptor Expression with Positron Emission Tomography.

The complexity of glucocorticoid receptor (GR) signaling cannot be measured with direct tissue analysis in living subjects, which has stifled our understanding of GR's role in human physiology or disease and impeded the development of selective GR modulators. Herein, we report 18F-5-(4-fluorobenzyl)-10-methoxy-2,2,4-trimethyl-2,5-dihydro-1H-chromeno[3,4-f]quinoline (18F-YJH08), a radioligand that enables noninvasive measurements of tissue autonomous GR expression levels in vivo with positron emission tomography (PET). YJH08 potently binds GR (Ki ∼ 0.4 nM) with ∼100-fold selectivity compared to nuclear hormone receptors in the same subfamily. 18F-YJH08 was prepared via Cu(OTf)2(py)4-mediated radiofluorination of an arylboronic acid pinacol ester with ∼12% decay corrected radiochemical yield from the starting 18F-fluoride ion. We applied treatment with the tissue-wide GR agonist dexamethasone and adrenalectomy and generated an adipocyte specific GR knockout mouse to show that 18F-YJH08 specifically binds GR in normal mouse tissues, including those for which aberrant GR expression is thought to drive severe diseases (e.g., brain, adipose tissue, kidneys). Remarkably, 18F-YJH08 PET also revealed that JG231, a potent and bioavailable HSP70 inhibitor, selectively degrades GR only in the adipose tissue of mice, a finding that foreshadows how GR targeted PET might be integrated into drug discovery to screen for selective GR modulation at the tissue level, beyond the historical screening that was performed at the transcriptional level. In summary, 18F-YJH08 enables a quantitative assessment of GR expression levels in real time among multiple tissues simultaneously, and this technology is a first step toward unraveling the daunting complexity of GR signaling and rationally engineering tissue specific therapeutic modulators in vivo

Massively targeted evaluation of therapeutic CRISPR off-targets in cells

Methods for sensitive and high-throughput evaluation of CRISPR RNA-guided nucleases (RGNs) off-targets (OTs) are essential for advancing RGN-based gene therapies. Here we report SURRO-seq for simultaneously evaluating thousands of therapeutic RGN OTs in cells. SURRO-seq captures RGN-induced indels in cells by pooled lentiviral OTs libraries and deep sequencing, an approach comparable and complementary to OTs detection by T7 endonuclease 1, GUIDE-seq, and CIRCLE-seq. Application of SURRO-seq to 8150 OTs from 110 therapeutic RGNs identifies significantly detectable indels in 783 OTs, of which 37 OTs are found in cancer genes and 23 OTs are further validated in five human cell lines by targeted amplicon sequencing. Finally, SURRO-seq reveals that thermodynamically stable wobble base pair (rG•dT) and free binding energy strongly affect RGN specificity. Our study emphasizes the necessity of thoroughly evaluating therapeutic RGN OTs to minimize inevitable off-target effects