Core-binding factor fusion downregulation of ADAR2 RNA editing contributes to AML leukemogenesis.

Adenosine-to-inosine RNA editing, which is catalyzed by adenosine deaminases acting on RNA (ADAR) family of enzymes, ADAR1 and ADAR2, has been shown to contribute to multiple cancers. However, other than the chronic myeloid leukemia blast crisis, relatively little is known about its role in other types of hematological malignancies. Here, we found that ADAR2, but not ADAR1 and ADAR3, was specifically downregulated in the core-binding factor (CBF) acute myeloid leukemia (AML) with t(8;21) or inv(16) translocations. In t(8;21) AML, RUNX1-driven transcription of ADAR2 was repressed by the RUNX1-ETO additional exon 9a fusion protein in a dominant-negative manner. Further functional studies confirmed that ADAR2 could suppress leukemogenesis specifically in t(8;21) and inv16 AML cells dependent on its RNA editing capability. Expression of 2 exemplary ADAR2-regulated RNA editing targets coatomer subunit α and component of oligomeric Golgi complex 3 inhibits the clonogenic growth of human t(8;21) AML cells. Our findings support a hitherto, unappreciated mechanism leading to ADAR2 dysregulation in CBF AML and highlight the functional relevance of loss of ADAR2-mediated RNA editing to CBF AML.

Comparing Low- or Standard-Dose Alteplase in Endovascular Thrombectomy: Insights From a Nationwide Registry.

BACKGROUND: Timely intravenous thrombolysis and endovascular thrombectomy are the standard reperfusion treatments for large vessel occlusion stroke. Currently, it is unknown whether a low-dose thrombolytic agent (0.6 mg/kg alteplase) can offer similar efficacy to the standard dose (0.9 mg/kg alteplase). METHODS: We enrolled consecutive patients in the multicenter Taiwan Registry of Endovascular Thrombectomy for Acute Ischemic Stroke who had received combined thrombolysis (within 4.5 hours of onset) and thrombectomy treatment from January 2019 to April 2023. The choice of low- or standard-dose alteplase was based on the physician's discretion. The outcomes included successful reperfusion (modified Thrombolysis in Cerebral Infarction score, 2b-3), symptomatic intracerebral hemorrhage, 90-day modified Rankin Scale score, and 90-day mortality. The outcomes between the 2 groups were compared using multivariable logistic regression and inverse probability of treatment weighting-adjusted analysis. RESULTS: Among the 2242 patients in the Taiwan Registry of Endovascular Thrombectomy for Acute Ischemic Stroke, 734 (33%) received intravenous alteplase. Patients in the low-dose group (n=360) were older, had more women, more atrial fibrillation, and longer onset-to-needle time compared with the standard-dose group (n=374). In comparison to low-dose alteplase, standard-dose alteplase was associated with a lower rate of successful reperfusion (81% versus 87%; adjusted odds ratio, 0.63 [95% CI, 0.40-0.98]), a numerically higher incidence of symptomatic intracerebral hemorrhage (6.7% versus 3.9%; adjusted odds ratio, 1.81 [95% CI, 0.88-3.69]), but better 90-day modified Rankin Scale score (functional independence [modified Rankin Scale score, 0-2], 47% versus 31%; adjusted odds ratio, 1.91 [95% CI, 1.28-2.86]), and a numerically lower mortality rate (9% versus 15%; adjusted odds ratio, 0.73 [95% CI, 0.43-1.25]) after adjusting for covariates. Similar results were observed in the inverse probability of treatment weighting-adjusted models. The results were consistent across predefined subgroups and age strata. CONCLUSIONS: Despite the lower rate of successful reperfusion and higher risk of symptomatic intracerebral hemorrhage with standard-dose alteplase, standard-dose alteplase was associated with a better functional outcome in patients receiving combined thrombolysis and thrombectomy.

Evolution of the coronavirus spike protein in the full-length genome and defective viral genome under diverse selection pressures.

How coronaviruses evolve by altering the structures of their full-length genome and defective viral genome (DVG) under dynamic selection pressures has not been studied. In this study, we aimed to experimentally identify the dynamic evolutionary patterns of the S protein sequence in the full-length genome and DVG under diverse selection pressures, including persistence, innate immunity and antiviral drugs. The evolutionary features of the S protein sequence in the full-length genome and in the DVG under diverse selection pressures are as follows: (i) the number of nucleotide (nt) mutations does not necessarily increase with the number of selection pressures; (ii) certain types of selection pressure(s) can lead to specific nt mutations; (iii) the mutated nt sequence can be reverted to the wild-type nt sequence under the certain type of selection pressure(s); (iv) the DVG can also undergo mutations and evolve independently of the full-length genome; and (v) DVG species are regulated during evolution under diverse selection pressures. The various evolutionary patterns of the S protein sequence in the full-length genome and DVG identified in this study may contribute to coronaviral fitness under diverse selection pressures.

Unveiling the biology of defective viral genomes in vitro and in vivo: implications for gene expression and pathogenesis of coronavirus.

BACKGROUND: Defective viral genome (DVG) is a truncated version of the full-length virus genome identified in most RNA viruses during infection. The synthesis of DVGs in coronavirus has been suggested; however, the fundamental characteristics of coronavirus DVGs in gene expression and pathogenesis have not been systematically analyzed. METHODS: Nanopore direct RNA sequencing was used to investigate the characteristics of coronavirus DVGs in gene expression including reproducibility, abundance, species and genome structures for bovine coronavirus in cells, and for mouse hepatitis virus (MHV)-A59 (a mouse coronavirus) in cells and in mice. The MHV-A59 full-length genomic cDNAs (~ 31 kilobases) were in vitro constructed to experimentally validate the origin of coronavirus DVG. The synthesis of DVGs was also experimentally identified by RT-PCR followed by sequencing. In addition, the alterations of DVGs in amounts and species under different infection environments and selection pressures including the treatment of antiviral remdesivir and interferon were evaluated based on the banding patterns by RT-PCR. RESULTS: The results are as follows: (i) the structures of DVGs are with diversity, (ii) DVGs are overall synthesized with moderate (MHV-A59 in cells) to high (BCoV in cells and MHV-A59 in mice) reproducibility under regular infection with the same virus inoculum, (iii) DVGs can be synthesized from the full-length coronavirus genome, (iv) the sequences flanking the recombination point of DVGs are AU-rich and thus may contribute to the recombination events during gene expression, (v) the species and amounts of DVG are altered under different infection environments, and (vi) the biological nature of DVGs between in vitro and in vivo is similar. CONCLUSIONS: The identified biological characteristics of coronavirus DVGs in terms of abundance, reproducibility, and variety extend the current model for coronavirus gene expression. In addition, the biological features of alterations in amounts and species of coronavirus DVGs under different infection environments may assist the coronavirus to adapt to the altered environments for virus fitness and may contribute to the coronavirus pathogenesis. Consequently, the unveiled biological features may assist the community to study the gene expression mechanisms of DVGs and their roles in pathogenesis, contributing to the development of antiviral strategy and public health.

Identification of the protein coding capability of coronavirus defective viral genomes by mass spectrometry.

During coronavirus infection, in addition to the well-known coronavirus genomes and subgenomic mRNAs, an abundance of defective viral genomes (DVGs) can also be synthesized. In this study, we aimed to examine whether DVGs can encode proteins in infected cells. Nanopore direct RNA sequencing and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis were employed. With the protein databases generated by nanopore direct RNA sequencing and the cell lysates derived from the RNA-protein pull-down assay, six DVG-encoded proteins were identified by LC-MS/MS based on the featured fusion peptides caused by recombination during DVG synthesis. The results suggest that the coronavirus DVGs have the capability to encode proteins. Consequently, future studies determining the biological function of DVG-encoded proteins may contribute to the understanding of their roles in coronavirus pathogenesis and the development of antiviral strategies.

Targeting the conserved coronavirus octamer motif GGAAGAGC is a strategy for the development of coronavirus vaccine.

BACKGROUND: Coronaviruses are pathogens of humans and animals that cause widespread and costly diseases. The development of effective strategies to combat the threat of coronaviruses is therefore a top priority. The conserved coronavirus octamer motif 5'GGAAGAGC3' exists in the 3' untranslated region of all identified coronaviruses. In the current study, we aimed to examine whether targeting the coronavirus octamer motif GGAAGAGC is a promising approach to develop coronavirus vaccine. METHODS: Plaque assays were used to determine the titers of mouse hepatitis virus (MHV)-A59 octamer mutant (MHVoctm) and wild-type (wt) MHV-A59 (MHVwt). Western blotting was used for the determination of translation efficiency of MHVoctm and MHVwt. Plaque assays and RT-qPCR were employed to examine whether MHVoctm was more sensitive to interferon treatment than MHVwt. Weight loss, clinical signs, survival rate, viral RNA detection and histopathological examination were used to evaluate whether MHVoctm was a vaccine candidate against MHVwt infection in BALB/c mice. RESULTS: In this study, we showed that (i) the MHVoctm with mutation of coronavirus octamer was able to grow to high titers but attenuated in mice, (ii) with the reduced multiplicity of infection (MOI), the difference in gene expression between MHVoctm and MHVwt became more evident in cultured cells, (iii) MHVoctm was more sensitive to interferon treatment than MHVwt and (iv) mice inoculated with MHVoctm were protected from MHVwt infection. CONCLUSIONS: Based on the results obtained from cultured cells, it was suggested that the synergistic effects of octamer mutation, multiplicity of infection and immune response may be a mechanism explaining the distinct phenotypes of octamer-mutated coronavirus in cell culture and mice. In addition, targeting the conserved coronavirus octamer motif is a strategy for development of coronavirus vaccine. Since the conserved octamer exists in all coronaviruses, this strategy of targeting the conserved octamer motif can also be applied to other human and animal coronaviruses for the development of coronavirus vaccines, especially the emergence of novel coronaviruses such as SARS-CoV-2, saving time and cost for vaccine development and disease control.

Biological characterization of coronavirus noncanonical transcripts in vitro and in vivo.

BACKGROUND: In addition to the well-known coronavirus genomes and subgenomic mRNAs, the existence of other coronavirus RNA species, which are collectively referred to as noncanonical transcripts, has been suggested; however, their biological characteristics have not yet been experimentally validated in vitro and in vivo. METHODS: To comprehensively determine the amounts, species and structures of noncanonical transcripts for bovine coronavirus in HRT-18 cells and mouse hepatitis virus A59, a mouse coronavirus, in mouse L cells and mice, nanopore direct RNA sequencing was employed. To experimentally validate the synthesis of noncanonical transcripts under regular infection, Northern blotting was performed. Both Northern blotting and nanopore direct RNA sequencing were also applied to examine the reproducibility of noncanonical transcripts. In addition, Northern blotting was also employed to determine the regulatory features of noncanonical transcripts under different infection conditions, including different cells, multiplicities of infection (MOIs) and coronavirus strains. RESULTS: In the current study, we (i) experimentally determined that coronavirus noncanonical transcripts were abundantly synthesized, (ii) classified the noncanonical transcripts into seven populations based on their structures and potential synthesis mechanisms, (iii) showed that the species and amounts of the noncanonical transcripts were reproducible during regular infection but regulated in altered infection environments, (iv) revealed that coronaviruses may employ various mechanisms to synthesize noncanonical transcripts, and (v) found that the biological characteristics of coronavirus noncanonical transcripts were similar between in vitro and in vivo conditions. CONCLUSIONS: The biological characteristics of noncanonical coronavirus transcripts were experimentally validated for the first time. The identified features of noncanonical transcripts in terms of abundance, reproducibility and variety extend the current model for coronavirus gene expression. The capability of coronaviruses to regulate the species and amounts of noncanonical transcripts may contribute to the pathogenesis of coronaviruses during infection, posing potential challenges in disease control. Thus, the biology of noncanonical transcripts both in vitro and in vivo revealed here can provide a database for biological research, contributing to the development of antiviral strategies.

Intravascular ultrasound guided vertebral artery stenting after basilar artery thrombectomy for acute brain stem stroke.

A 64-year-old lady presented as right vertebral artery occlusion and brain stem stroke (Figure 1A). Emergent thrombectomy opened the artery, but it re-occluded 10 minutes later (Figure 1B,C). Intravascular ultrasound showed heavy plaque burden and guided a balloon-expandable stenting successfully (Figure 1D-F).

Single-incision versus four-incision laparoscopic transfistulous bile duct exploration for Mirizzi syndrome type II.

BACKGROUND: We developed laparoscopic transfistulous bile duct exploration (LTBDE) for Mirizzi syndrome (MS) McSherry type II in September 2011. Then, single-incision LTBDE (SILTBDE) was adopted as a preferred technique since August 2013. This retrospective study aims to analyze the outcome of LTBDE in 7.7 years and to compare SILTBDE with four-incision LTBDE (4ILTBDE). METHODS: Seventeen consecutive patients underwent LTBDE for MS McSherry type II from September 2011 to May 2019. Transfistulous removal of the impacted stone(s), choledochoscopic bile duct exploration, and primary closure of the gallbladder remnant were performed without biliary drainage. RESULTS: The sex ratio is 12:5 (male: female) with an average age of 39.4 ± 10.3 (24-56) years. Ten patients (58.8%) had their diagnoses of MS established by preoperative imaging. According to the Csendes classification, three type II (17.6%), nine type III (52.9%), and five type IV (29.4%) were identified. The operative time was 264.8 ± 60.3 min (156-358 min). The stone clearance rate was 100%. The postoperative hospital stay was 4.7 ± 1.9 (2-10) days. No procedure was converted to an open operation. Two postoperative transient hyperamylasemia (11.8%) and one superficial wound infection (5.9%) occurred and all recovered well under conservative treatment (Clavien-Dindo grade I). During an average 2.2-year follow-up period, no biliary stricture or stone recurrence occurred. No significant difference exists between the SILTBDE and 4ILTBDE groups. Nevertheless, an insignificant trend of shorter postoperative hospital stay was observed in the former. A diagnosis of MS Csendes type IV implicates prolonged total and postoperative hospital stays (p < 0.01). CONCLUSIONS: LTBDE is safe and efficacious for MS McSherry type II. It provides a simple solution for various types of MS and avoids undesirable complications following bilioenteric anastomosis. SILTBDE is comparable to 4ILTBDE for selected patients. Patients with MS Csendes type IV need more time to recover after surgery.

Targeting RNA editing of antizyme inhibitor 1: A potential oligonucleotide-based antisense therapy for cancer.

Dysregulated adenosine-to-inosine (A-to-I) RNA editing is implicated in various cancers. However, no available RNA editing inhibitors have so far been developed to inhibit cancer-associated RNA editing events. Here, we decipher the RNA secondary structure of antizyme inhibitor 1 (AZIN1), one of the best-studied A-to-I editing targets in cancer, by locating its editing site complementary sequence (ECS) at the 3' end of exon 12. Chemically modified antisense oligonucleotides (ASOs) that target the editing region of AZIN1 caused a substantial exon 11 skipping, whereas ECS-targeting ASOs effectively abolished AZIN1 editing without affecting splicing and translation. We demonstrate that complete 2'-O-methyl (2'-O-Me) sugar ring modification in combination with partial phosphorothioate (PS) backbone modification may be an optimal chemistry for editing inhibition. ASO3.2, which targets the ECS, specifically inhibits cancer cell viability in vitro and tumor incidence and growth in xenograft models. Our results demonstrate that this AZIN1-targeting, ASO-based therapeutics may be applicable to a wide range of tumor types.

RNA editing mediates the functional switch of COPA in a novel mechanism of hepatocarcinogenesis.

BACKGROUND & AIMS: RNA editing introduces nucleotide changes in RNA sequences. Recent studies have reported that aberrant adenosine-to-inosine RNA editing is implicated in cancers. Until now, very few functionally important protein-recoding editing targets have been discovered. Here, we investigated the role of a recently discovered protein-recoding editing target COPA (coatomer subunit α) in hepatocellular carcinoma (HCC). METHODS: Clinical implication of COPA editing was studied in a cohort of 125 HCC patients. CRISPR/Cas9-mediated knockout of the editing site complementary sequence (ECS) was used to delete edited COPA transcripts endogenously. COPA editing-mediated change in its transcript or protein stability was investigated upon actinomycin D or cycloheximide treatment, respectively. Functional difference in tumourigenesis between wild-type and edited COPA (COPAWTvs. COPAI164V) and the exact mechanisms were also studied in cell models and mice. RESULTS: ADAR2 binds to double-stranded RNA formed between edited exon 6 and the ECS at intron 6 of COPA pre-mRNA, causing an isoleucine-to-valine substitution at residue 164. Reduced editing of COPA is implicated in the pathogenesis of HCC, and more importantly, it may be involved in many cancer types. Upon editing, COPAWT switches from a tumour-promoting gene to a tumour suppressor that has a dominant-negative effect. Moreover, COPAI164V may undergo protein conformational change and therefore become less stable than COPAWT. Mechanistically, COPAI164V may deactivate the PI3K/AKT/mTOR pathway through downregulation of caveolin-1 (CAV1). CONCLUSIONS: We uncover an RNA editing-associated mechanism of hepatocarcinogenesis by which downregulation of ADAR2 caused the loss of tumour suppressive COPAI164V and concurrent accumulation of tumour-promoting COPAWT in tumours; a rapid degradation of COPAI164V protein and hyper-activation of the PI3K/AKT/mTOR pathway further promote tumourigenesis. LAY SUMMARY: RNA editing is a process in which RNA is changed after it is made from DNA, resulting in an altered gene product. In this study, we found that RNA editing of a gene known as coatomer subunit α (COPA) is lower in tumour samples and discovered that this editing process changes COPA protein from a tumour-promoting form to a tumour-suppressive form. Loss of the edited COPA promotes the development of liver cancer.

Allometric scaling and growth: Evaluation and applications in subadult body mass estimation.

OBJECTIVES: Previously developed methods in subadult body mass estimation have not been tested in populations other than European-American or African-American. This study uses a contemporary Taiwanese sample to test these methods. Through evaluating their accuracy and bias, we addressed whether the allometric relationships between body mass and skeletal traits commonly used in subadult body mass estimation are conserved among different populations. MATERIALS AND METHODS: Computed tomography scans of lower limbs from individuals aged 0-17 years old of both sexes were collected from National Taiwan University Hospital along with documented body weight. Polar second moment of area, distal femoral metaphyseal breadth, and maximum superior/inferior femoral head diameter were collected either directly from the scans or from reconstructed 3D models. Estimated body mass was compared with documented body mass to assess the performance of the equations. RESULTS: Current methods provided good body mass estimates in Taiwanese individuals, with accuracy and bias similar to those reported in other validation studies. A tendency for increasing error with increasing age was observed for all methods. Reduced major axis regression showed the allometric relationships between different skeletal traits and body mass across different age categories can all be summarized using a common fitted line. A revised, maximum likelihood-based approach was proposed for all skeletal traits. DISCUSSION: The results suggested that the allometric relationships between body mass and different skeletal traits are largely conserved among populations. The revised method provided improved applicability with strong underlying theoretical justifications, and potential for future improvements.

Prediction of mTICI 3 recanalization and clinical outcomes in endovascular thrombectomy for acute ischemic stroke: a retrospective study in the Taiwan registry.

PURPOSE: Early recanalization for acute ischemic stroke (AIS) due to large vessel occlusion (LVO) by endovascular thrombectomy (EVT) is strongly related to improved functional outcomes. With data obtained from the Taiwan registry, the factors associated with mTICI 3 recanalization and clinical outcomes in EVT are investigated. METHODS: From January 2014 to September 2016, 108 patients who underwent EVT for AIS due to LVO in 11 medical centers throughout Taiwan were included. Complete recanalization is defined as achieving modified thrombolysis in cerebral infarction (mTICI) grade 3. Good clinical outcomes are defined by the modified Rankin scale (mRS) 0-2 at 3 months after EVT. Clinical and imaging parameters for predicting mTICI 3 recanalization and good clinical outcomes are analyzed. RESULTS: Of the 108 patients who received EVT, 54 (50%) patients had mTICI 3 recanalization. Having received aspiration only and the use of IV-tPA are shown to be significant predictors for mTICI 3 recanalization with odds ratios of 2.61 and 2.53 respectively. Forty-six (42.6%) patients experienced good 3-month clinical outcomes (mRS 0-2). Pretreatment collateral statuses, NIHSS scores, time lapses between symptoms to needle, and the occurrence of hemorrhage at 24 h are all significant predictors for good outcomes with odds ratios of 2.88, 0.91, 0.99, and 0.31 respectively. CONCLUSIONS: Prediction of mTICI 3 recanalization and clinical outcomes offer valuable clinical information for treatment planning in EVT.

Targeting cancer addiction for SALL4 by shifting its transcriptome with a pharmacologic peptide.

Sal-like 4 (SALL4) is a nuclear factor central to the maintenance of stem cell pluripotency and is a key component in hepatocellular carcinoma, a malignancy with no effective treatment. In cancer cells, SALL4 associates with nucleosome remodeling deacetylase (NuRD) to silence tumor-suppressor genes, such as PTEN. Here, we determined the crystal structure of an amino-terminal peptide of SALL4(1-12) complexed to RBBp4, the chaperone subunit of NuRD, at 2.7 Å, and subsequent design of a potent therapeutic SALL4 peptide (FFW) capable of antagonizing the SALL4-NURD interaction using systematic truncation and amino acid substitution studies. FFW peptide disruption of the SALL4-NuRD complex resulted in unidirectional up-regulation of transcripts, turning SALL4 from a dual transcription repressor-activator mode to singular transcription activator mode. We demonstrate that FFW has a target affinity of 23 nM, and displays significant antitumor effects, inhibiting tumor growth by 85% in xenograft mouse models. Using transcriptome and survival analysis, we discovered that the peptide inhibits the transcription-repressor function of SALL4 and causes massive up-regulation of transcripts that are beneficial to patient survival. This study supports the SALL4-NuRD complex as a drug target and FFW as a viable drug candidate, showcasing an effective strategy to accurately target oncogenes previously considered undruggable.

Practice and technique of using face mask amongst adults in the community: a cross-sectional descriptive study.

BACKGROUND: The proper use of face mask comprises the correct practice and wearing technique and is important in preventing the spread of respiratory infections. Previous studies have addressed only the aspect of practice and failed to provide a detailed account of face mask usage amongst community-based populations. This study examined the practice and technique of using face mask amongst adults. METHODS: A cross-sectional descriptive design was adopted. A quota sample of 1500 adults was recruited in Hong Kong during a nonepidemic state between January and February 2017. The participants' practice of using face mask in five given situations was assessed using a questionnaire. Their technique in using face mask, including 12 steps, was assessed using an observation checklist. Statistical tests were used to compare the differences in practice and technique amongst adults of different gender and age groups. RESULTS: Findings revealed that the performance of the participants in both categories was unsatisfactory. In terms of practice, less than one-fifth of the participants reported that they always wore face mask when taking care of family members with fever (14.7%) or respiratory infections (19.5%). Male adults and those aged 55-64 reported low frequency in using face mask during required situations. In terms of technique, none of the participants performed all the required steps in using face mask correctly. More than 90% of the participants did not perform hand hygiene before putting on (91.5%), taking off (97.3%), or after disposing (91.5%) face mask. Adults aged 55 and above performed poorer than adults in the younger age groups. CONCLUSION: Compared with previous findings obtained during an epidemic, the performance of the participants during a nonepidemic state was less satisfactory. The possibility of developing fatigue after exposure to repeated epidemics was discussed. This study contributes to a comprehensive understanding of the use of face mask in a community and reveals the underperformed areas. Effort is required to enhance the proper practice of using face mask, convey the message that hand hygiene is an essential step in wearing and taking off a face mask and increase the public's general concern in the value of using face mask.

In vivo imaging of insulin-secreting human pancreatic ductal cells using MRI reporter gene technique: A feasibility study.

PURPOSE: The purpose of this study was to investigate the feasibility of in vivo imaging of human pancreatic ductal cells by OATP1B3 reporter gene under MRI. METHODS: A human cell line (PANC-1) derived from the pancreatic ductal epithelium was used in this study. After transduction of OATP1B3, the cellular physiological functions and the ability of intracellular uptake of the MRI contrast medium (Gd-EOB-DTPA) were examined. Induced differentiation of the PANC-1 cells into hormone-secreting cells were performed to simulate pancreatic ß-like cells. The hormone-secreting cells were implanted into rats and in vivo MRI was evaluated. RESULTS: The mRNA and proteins of OATP1B3 were highly expressed. No significant change of cellular physiological functions was found after the expression. After induced differentiation, the hormone secretion capacities of the OATP1B3-expressing PANC-1 cells were confirmed. Intra-cellular uptake of Gd-EOB-DTPA was determined in vitro by inductively coupled plasma mass spectrometry and MRI. In vivo MRI of the OATP1B3-expressing xenograft revealed an increased signal intensity after contrast enhancement. CONCLUSION: OATP1B3 can be used as a safe and feasible in vivo MRI gene reporter for human pancreatic ductal cells.

Organic anion-transporting polypeptide 1B3 as a dual reporter gene for fluorescence and magnetic resonance imaging.

Reporter proteins have broad applications in visualizing molecular events at the cellular, tissue and whole-body levels. Transmembrane transporters recognizing specific molecular domains are of particular interest because they enable the migration of signal-source molecules from the extracellular space to the cytoplasm for subsequent application in multimodality imaging. Organic anion-transporting polypeptides (OATPs) have demonstrated their MRI reporter efficacy. We further expanded their use as a dual-modality reporter in MRI and noninvasive in vivo imaging system (IVIS). We overexpressed OATP1B3 in the HT-1080 sarcoma cell line. Both Gd-EOB-DTPA, an MRI contrast agent, and indocyanine green (ICG), a near-infrared fluorescent dye that provides better deep-tissue detection because of its long wavelength, could be delivered to the intracellular space and imaged in a tumor-bearing nude mouse model. Our in vivo dual-imaging reporter system achieved high sensitivity in MRI and observation periods lasting as long as 96 h in IVIS. Because of the superior temporal and spatial resolutions and the clinical availability of both ICG and Gd-EOB-DTPA, this dual-imaging OATP1B3 system will find biomedical use in tumor biology, stem cell trafficking, and tissue engineering.-Wu, M.-R., Liu, H.-M., Lu, C.-W., Shen, W.-H., Lin, I.-J., Liao, L.-W., Huang, Y.-Y., Shieh, M.-J., Hsiao, J.-K. Organic anion-transporting polypeptide 1B3 as a dual reporter gene for fluorescence and magnetic resonance imaging.

An RNA editing/dsRNA binding-independent gene regulatory mechanism of ADARs and its clinical implication in cancer.

Adenosine-to-inosine (A-to-I) RNA editing, catalyzed by Adenosine DeAminases acting on double-stranded RNA(dsRNA) (ADAR), occurs predominantly in the 3' untranslated regions (3'UTRs) of spliced mRNA. Here we uncover an unanticipated link between ADARs (ADAR1 and ADAR2) and the expression of target genes undergoing extensive 3'UTR editing. Using METTL7A (Methyltransferase Like 7A), a novel tumor suppressor gene with multiple editing sites at its 3'UTR, we demonstrate that its expression could be repressed by ADARs beyond their RNA editing and double-stranded RNA (dsRNA) binding functions. ADARs interact with Dicer to augment the processing of pre-miR-27a to mature miR-27a. Consequently, mature miR-27a targets the METTL7A 3'UTR to repress its expression level. In sum, our study unveils that the extensive 3'UTR editing of METTL7A is merely a footprint of ADAR binding, and there are a subset of target genes that are equivalently regulated by ADAR1 and ADAR2 through their non-canonical RNA editing and dsRNA binding-independent functions, albeit maybe less common. The functional significance of ADARs is much more diverse than previously appreciated and this gene regulatory function of ADARs is most likely to be of high biological importance beyond the best-studied editing function. This non-editing side of ADARs opens another door to target cancer.

Diagnostic accuracy of CTA and MRI/MRA in the evaluation of the cortical venous reflux in the intracranial dural arteriovenous fistula DAVF.

PURPOSE: Computed tomography angiography (CTA) and magnetic resonance imaging/angiography (MRI/MRA) are used for the diagnosis of intracranial dural arteriovenous fistulas (DAVFs). The purpose of this study was to compare the diagnostic accuracy of CTA and magnetic resonance imaging/angiography (MRI/MRA) for detection of cortical venous reflux (CVR) in intracranial DAVFs. METHODS: The records of patients with angiography-confirmed intracranial DAVFs who also received CTA and MRI/MRA from January 2008 to July 2016 were reviewed. CTA and MRI/MRA were reviewed for signs of CVR, and the diagnostic accuracy of individual signs was evaluated by receiver operating curve (ROC) analysis. RESULTS: A total 108 patients were included in this study. CTA signs of CVR included abnormal dilatation, early enhancement, and the presence of a medullary or pial vein. MRI/MRA signs of CVR included abnormal dilatation, early enhancement, flow-related enhancement, flow void, and medullary or pial venous collaterals. The sensitivity of individual CTA signs ranged from 62 to 96%, and specificities from 79 to 94%. The sensitivities of individual MRI/MRA signs ranged from 58 to 83%, and specificities from 77 to 93%. The area under ROC curve (AUC) of CTA and MRI/MRA were 0.91 and 0.87, respectively (P = 0.04 in direct comparison). In subgroup analysis, CTA had better diagnostic accuracy for higher grade disease (P = 0.05) and non-aggressive manifestation (P = 0.04). CONCLUSIONS: Both CTA and MRI/MRA have good diagnostic accuracy for detection of CVR in patients with intracranial DAVFs. There is modest evidence that CTA is better than MRI/MRA.

Endovascular thrombectomy for acute ischemic stroke: A single-center experience in Taiwan.

BACKGROUND/PURPOSE: Endovascular thrombectomy has been strongly recommended for treatment of acute ischemic stroke (AIS) with large vessel occlusion. This study aimed to evaluate its efficacy and safety in an Asian population from a single center in Taiwan. METHODS: Patients who experienced AIS and received endovascular thrombectomy during the period of September 2014 to September 2016 at National Taiwan University Hospital were included. Factors related to favorable outcome, defined as modified Rankin scale 0-2 at 90 days after stroke, were analyzed. RESULTS: During the study period, 65 patients (mean age, 71.9 ± 12.4 years; 44.6% females) received endovascular thrombectomy, including 33 who received intravenous thrombolysis before the endovascular treatment. A significant trend of increasing thrombectomy therapy was observed. The median National Institutes of Health Stroke Scale (NIHSS) score on admission was 19 (interquartile range, 15-26). The sites of vessel occlusion were middle cerebral artery in 47 (72.3%) patients, intracranial internal carotid artery in 8 (12.4%), anterior cerebral artery in 1 (1.5%), and basilar artery in 9 (13.8%). The median times from stroke onset to groin puncture and from groin puncture to recanalization time were 200 and 29.5 min, respectively. Successful revascularization was achieved in 41 (63.1%) patients. Two (3.1%) patients had symptomatic hemorrhagic transformation. At 90 days, 25 (38.5%) patients achieved favorable outcome. A shorter time from onset to puncture, and successful recanalization were independent predictors of favorable outcome. CONCLUSION: This study demonstrated the therapeutic promise of endovascular thrombectomy for treatment of AIS with large vessel occlusion in a clinical setting.