renal

A bimolecular modification strategy for developing long-lasting bone anabolic aptamer

AUTHORS

Huarui Zhang, Sifan Yu, Shuaijian Ni, Amu Gubu, Yuan Ma, Yihao Zhang, Haitian Li, Yuzhe Wang, Luyao Wang, Zongkang Zhang, Yuanyuan Yu, Aiping Lyu, Baoting Zhang, Ge Zhang

ABSTRACT

The molecular weight of nucleic acid aptamers (20 kDa) is lower than the cutoff threshold of the renal filtration (30–50 kDa), resulting in a very short half-life, which dramatically limits their druggability. To address this, we utilized 3-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-N-(4-hydroxy-2-oxo-2H-chromen-6-yl)propenamide (HC) and 12-((2,5-dioxopyrrolidin-1-yl)oxy)-12-oxododecanoic acid (DA), two newly designed coupling agents, for synergistic binding to human serum albumin (HSA). Both HC and DA are conjugated to a bone anabolic aptamer (Apc001) against sclerostin to form an Apc001OC conjugate with high binding affinity to HSA. Notably, HC and DA could synergistically facilitate prolonging the half-life of the conjugated Apc001 and promoting its bone anabolic potential. Using the designed blocking peptides, the mechanism studies indicate that the synergistic effect of HC-DA on pharmacokinetics and bone anabolic potential of the conjugated Apc001 is achieved via their synergistic binding to HSA. Moreover, biweekly Apc001OC at 50 mg/kg shows comparable bone anabolic potential to the marketed sclerostin antibody given weekly at 25 mg/kg. This proposed bimolecular modification strategy could help address the druggability challenge for aptamers with a short half-life.

Vascular architectural patterns in clear cell renal cell carcinoma and clear cell papillary renal cell carcinoma

AUTHORS

Sofia Canete-Portillo, Maria del Carmen Rodriguez Pena, Dezhi Wang, Diego F. Sanchez, George J. Netto & Cristina Magi-Galluzzi

ABSTRACT

Renal cell carcinomas (RCC) are well-vascularized tumors. Although clear cell RCC (CCRCC) show a characteristic vascular network, some cases show overlapping features with other RCC. We aimed to evaluate vascular architectural patterns, microvessel density (MVD), and endothelial cell density (ECD) in CCRCC compared to clear cell papillary RCC (ccpRCC). Thirty-four RCC (17 CCRCC and 17 ccpRCC) were included in the study. CD34 was used to evaluate vascular architectural patterns by microscopic estimation in all cases. CD34, ERG, and Bioquant Osteo 2019 Imaging Analysis Software were used to evaluate MVD and ECD in 17 CCRCC and 15 ccpRCC. Mean MVD was 526.63 in CCRCC vs. 426.18 in ccpRCC (p = 0.16); mean ECD was 937.50 in CCRCC vs. 1060.21 in ccpRCC (p = 0.25). CD34 highlighted four distinct vascular architectural patterns: pseudoacinar, Golgi-like, lacunae, and scattered. Lacunae and pseudoacinar was the most frequent combination in CCRCC; lacunae and Golgi-like was the predominant combination among ccpRCC. Pseudoacinar was most extensive in CCRCC and least in ccpRCC; Golgi-like was predominant in ccpRCC and uncommon in CCRCC. The extent of pseudoacinar and Golgi-like vascular architectural patterns was significantly different between CCRCC and ccpRCC (p < 0.05). Pathologists acquainted with these different vascular architectural patterns may utilize them as an additional tool in the distinction of CCRCC from ccpRCC.

Lifelong challenge of calcium homeostasis in male mice lacking TRPV5 leads to changes in bone and calcium metabolism

Authors

Bram C. J. van der Eerden, W. Nadia H. Koek, Paul Roschger, M. Carola Zillikens, Jan H. Waarsing, Annemiete van der Kemp, Marijke Schreuders-Koedam, Nadja Fratzl-Zelman, Pieter J. M. Leenen, Joost G. J. Hoenderop,
Klaus Klaushofer, René J. M. Bindels and Johannes P.T.M. van Leeuwen

Abstract

Trpv5 plays an important role in calcium (Ca2+) homeostasis, among others by mediating renal calcium reabsorption. Accordingly, Trpv5 deficiency strongly stresses Ca2+ homeostasis in order to maintain stable serum Ca2+. We addressed the impact of lifelong challenge of calcium homeostasis on the bone phenotype of these mice. Aging significantly increased serum 1,25(OH)2D3 and PTH levels in both genotypes but they were more elevated in Trpv5-/- mice, whereas serum Ca2+ was not affected by age or genotype. Age-related changes in trabecular and cortical bone mass were accelerated in Trpv5-/- mice, including reduced trabecular and cortical bone thickness as well as reduced bone mineralization. No effect of Trpv5 deficiency on bone strength was observed. In 78-week-old mice no differences were observed between the genotypes regarding urinary deoxypyridinoline, osteoclast number, differentiation and activity as well as osteoclast precursor numbers, as assessed by flow cytometry. In conclusion, life-long challenge of Ca2+ homeostasis present in Trpv5-/- mice causes accelerated bone aging and a low cortical and trabecular bone mass phenotype. The phenotype of the Trpv5-/- mice suggests that maintenance of adequate circulatory Ca2+ levels in patients with disturbances in Ca2+ homeostasis should be a priority in order to prevent bone loss at older age.

Link to Article

http://www.physiomics.eu/media/210426/j_biol_chem_xx_xx-xx__2016.1.pdf