Search bioRxiv⌕ Search

Biology subjects

Ozeki, A. N.

Publications and source records attributed to Ozeki, A. N..

2 recordsLinked to original sources

RNA degradation modulates unique aging-related gene expression in naked mole-rats

Gene expression is co-regulated by the rates of RNA synthesis and degradation, and recent evidence has linked their imbalance to the onset of aging. The naked mole-rat (NMR) is a small rodent with an exceptionally long lifespan and markedly delayed aging, yet little is known about its RNA synthesis and degradation characteristics compared to other rodents that age more rapidly. Here, we investigate RNA synthesis and degradation in NMR and mouse skin fibroblasts by monitoring incorporation of a uridine analog, 4-thiouridine. Cross-species analysis showed that the NMR cells have higher overall rates of RNA synthesis and degradation. It further revealed higher RNA degradation rates in aging-related pathways, notably Mtorc1 signaling, likely contributing to reducing the overall expression. Although known aging-associated genes, including Xrcc5, Nudt1, Fen1, and Aptx, were expressed at similar levels in NMR and mouse fibroblasts, the RNA turnover rates were largely altered. To uncover the underlying mechanism enabling differential control of RNA kinetics, we analyzed the transcript feature importance by machine learning and identified key features governing RNA degradation both common and unique in NMR and mouse fibroblasts. Our data highlight a potential role of RNA synthesis and degradation as hidden layers of gene regulation in NMR.

molecular biology↗

Radiolabeling of PSMA-617 with 89Zr: A Novel Use of DMSO for Radiochemical Yield Enhancement and Preliminary Small-Animal PET Results

IntroductionProstate-specific membrane antigen (PSMA)-targeted ligands, including PSMA-617, have been developed for theranostics of prostate cancer. 68Ga-PSMA-617 is the de facto standard of PSMA Positron Emission Tomography (PET) for imaging in prostate cancer patients prior to radioligand therapy (RLT) with 177Lu-PSMA-617. The dose-limiting toxicity for PSMA-RLT is damage to the kidney. PET scans using 68Ga-PSMA-617 have to be performed within a few hours of injection due to its short half-life (68 min). However, the presence of radioactivity in urine at the PET imaging timepoint hampers the dose optimization of 177Lu (half-life 6.6 d)-labeled PSMA-617. Thus, the long-lived positron emitter 89Zr (half-life 3.3 d) is suited for optimizing the doses of 177Lu-PSMA-617 because PET scans can be performed after excretion of radioactive urine. Although 89Zr has great potential for PET imaging, its inadequate incorporation into 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), limits its applications. Here, we report the radiolabeling of PSMA-617 with 89Zr and preliminary PET imaging studies using 89Zr-PSMA-617. MethodsDMSO and HEPES buffer were used to label PSMA-617 with 89Zr. The dissociation constant (Kd) of 89Zr-PSMA-617 was determined using a cell-binding assay. Delayed-PET scans using 89Zr-PSMA-617 were performed at 24 h (N = 5). Results89Zr-PSMA-617 was prepared with a radiochemical yield of 70 {+/-} 9%. The Kd value was 6.8 nM. In PET imaging, standardized uptake value (SUV) was highest in LNCaP tumors (SUVmax = 0.98 {+/-} 0.32), whereas it was low in kidney (SUVmax = 0.18 {+/-} 0.7). ConclusionThe preparation of 89Zr-PSMA-617 was achieved by using the DMSO and HEPES buffer. 89Zr-PSMA-617 visualize the PSMA positive LNCaP tumors without accumulation in bladder. Advances in knowledge and implications for patient careThe use of 89Zr-PSMA-617 to predict the radiation doses in normal tissues lead to safe and effective RLT with 177Lu-PSMA-617.

cancer biology↗