Pudexacianinium (ASP5354) chloride for ureter visualization in participants undergoing laparoscopic, minimally invasive colorectal surgery.

BACKGROUND: Intraoperative ureteral injury, a serious complication of abdominopelvic surgeries, can be avoided through ureter visualization. Near-infrared fluorescence imaging offers real-time anatomical visualization of ureters during surgery. Pudexacianinium (ASP5354) chloride is an indocyanine green derivative under investigation for intraoperative ureter visualization during colorectal or gynecologic surgery in adult and pediatric patients. METHODS: In this phase 2 study (NCT04238481), adults undergoing laparoscopic colorectal surgery were randomized to receive one intravenous dose of pudexacianinium 0.3 mg, 1.0 mg, or 3.0 mg. The primary endpoint was successful intraoperative ureter visualization, defined as observation of ureter fluorescence 30 min after pudexacianinium administration and at end of surgery. Safety and pharmacokinetics were also assessed. RESULTS: Participants received pudexacianinium 0.3 mg (n = 3), 1.0 mg (n = 6), or 3.0 mg (n = 3). Most participants were female (n = 10; 83.3%); median age was 54 years (range 24-69) and median BMI was 29.3 kg/m2 (range 18.7-38.1). Successful intraoperative ureter visualization occurred in 2/3, 5/6, and 3/3 participants who received pudexacianinium 0.3 mg, 1.0 mg, or 3.0 mg, respectively. Median intensity values per surgeon assessment were 1 (mild) with the 0.3-mg dose, 2 (moderate) with the 1.0-mg dose, and 3 (strong) with the 3.0-mg dose. A correlation was observed between qualitative (surgeon's recognition/identification of the ureter during surgery) and quantitative (video recordings of the surgeries after study completion) assessment of fluorescence intensity. Two participants experienced serious adverse events, none of which were drug-related toxicities. One adverse event (grade 1 proteinuria) was related to pudexacianinium. Plasma pudexacianinium concentrations were dose-dependent and the mean (± SD) percent excreted into urine during surgery was 22.3% ± 8.0% (0.3-mg dose), 15.6% ± 10.0% (1.0-mg dose), and 39.5% ± 12.4% (3.0-mg dose). CONCLUSIONS: In this study, 1.0 and 3.0 mg pudexacianinium provided ureteral visualization for the duration of minimally invasive, laparoscopic colorectal procedures and was safe and well tolerated.

Translational inhibition by deadenylation-independent mechanisms is central to microRNA-mediated silencing in zebrafish.

MicroRNA (miRNA) is a class of small noncoding RNA approximately 22 nt in length. Animal miRNA silences complementary mRNAs via translational inhibition, deadenylation, and mRNA degradation. However, the underlying molecular mechanisms remain unclear. A key question is whether these three outputs are independently induced by miRNA through distinct mechanisms or sequentially induced within a single molecular pathway. Here, we successfully dissected these intricate outputs of miRNA-mediated repression using zebrafish embryos as a model system. Our results indicate that translational inhibition and deadenylation are independent outputs mediated by distinct domains of TNRC6A, which is an effector protein in the miRNA pathway. Translational inhibition by TNRC6A is divided into two mechanisms: PAM2 motif-mediated interference of poly(A)-binding protein (PABP), and inhibition of 5' cap- and poly(A) tail-independent step(s) by a previously undescribed P-GL motif. Consistent with these observations, we show that, in zebrafish embryos, miRNA inhibits translation of the target mRNA in a deadenylation- and PABP-independent manner at early time points. These results indicate that miRNA exerts multiple posttranscriptional outputs via physically and functionally independent mechanisms and that direct translational inhibition is central to miRNA-mediated repression.