Ontogeny of the Kidney and Renal Developmental Markers in the Rhesus Monkey (Macaca Mulatta)

Abstract

Nonhuman primates share many developmental similarities with humans, thus they provide an important preclinical model for understanding the ontogeny of biomarkers of kidney development and assessing new cell-based therapies to treat human disease. To identify morphological and developmental changes in protein and RNA expression patterns during nephrogenesis, immunohistochemistry and quantitative real-time PCR were used to assess temporal and spatial expression of WT1, Pax2, Nestin, Synaptopodin, alpha-smooth muscle actin (α-SMA), CD31, vascular endothelial growth factor (VEGF), and Gremlin. Pax2 was expressed in the condensed mesenchyme surrounding the ureteric bud and in the early renal vesicle. WT1 and Nestin were diffusely expressed in the metanephric mesenchyme, and expression increased as the Pax2-positive condensed mesenchyme differentiated. The inner cleft of the tail of the S-shaped body contained the podocyte progenitors (visceral epithelium) that were shown to express Pax2, Nestin, and WT1 in the early second trimester. With maturation of the kidney, Pax2 expression diminished in these structures, but was retained in cells of the parietal epithelium, and as WT1 expression was upregulated. Mature podocytes expressing WT1, Nestin, and Synaptopodin were observed from the mid-third trimester through adulthood. The developing glomerulus was positive for α-SMA (vascular smooth muscle) and Gremlin (mesangial cells), CD31 (glomerular endothelium), and VEGF (endothelium), and showed loss of expression of these markers as glomerular maturation was completed. These data form the basis for understanding nephrogenesis in the rhesus monkey and will be useful in translational studies that focus on embryonic stem and other progenitor cell populations for renal tissue engineering and repair.

Growth velocity and weaning δ15N “Dips” during ontogeny in Macaca mulatta

“…Energy and resources are not allocated homogeneously during growth and development, but are rationed for different systems at different times, according to the expectations of life-history theory (Pereira, 2002). Among primates, somatic, neural and dental development follow different growth trajectories (c.f., Batchelder et al, 2010;Dobbing and Sands, 1979;Leigh, 1992;Malkova et al, 2006). These may be growing rapidly at the time of the "dip," in pace with infant tissue d 15 N, shifting the routing of food d 15 N from body growth to the growth, development and maintenance of other biological systems.…”

“…These may be growing rapidly at the time of the "dip," in pace with infant tissue d 15 N, shifting the routing of food d 15 N from body growth to the growth, development and maintenance of other biological systems. Thus, it is recommended that future research in this area consider growth rates of other systems more specifically (e.g., digestive, renal, reproductive, cardiovascular, lymphatic, nervous), using standard or advanced imaging, or other proxy indicators (c.f., Batchelder et al, 2010). It is also recommended that future research take growth measurements at intervals that correspond with the turnover time of the tissue analyzed.…”

Renal Tissue Engineering with Decellularized Rhesus Monkey Kidneys: Age-Related Differences

“…ICC and IHC were performed on chamber slides and on paraffin-embedded sections (5-6 mm), respectively, for cytoskeletal and renal-specific proteins using established protocols. 13,16 Briefly, chamber slides were washed in PBS for 5 min before fixing in cold methanol for 10 min at £-20°C. Slides were blocked with 2% goat serum (Sigma-Aldrich) in blocking buffer (1% BSA in PBS) for 20 min at room…”

“…Quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure the expression of renal markers including aquaporin-2 (water channel, proximal tubules), CD31 (glomerular endothelium), nestin (podocytes), Pax2 (induced metanephric mesenchyme), synaptopodin (podocytes), vimentin (mesenchyme), WT1 (induced metanephric mesenchyme, renal vesicle, early podocytes), and the housekeeping gene elongation factor 1-alpha (EF1-a) 12,16 ( Table 2). Total RNA was extracted from cells preserved in RLT buffer at £-20°C using the RNeasy kit (RNeasy Ò Plus Mini Kit; Qiagen) following the manufacturer's instructions.…”

Radiolabeling and In Vivo Imaging of Transplanted Renal Lineages Differentiated from Human Embryonic Stem Cells in Fetal Rhesus Monkeys

“…Investigations have focused on renal ontogeny in the monkey and the use of different stem and progenitor cell populations for novel renal transplant protocols [9, 10]. In vivo imaging technologies are important to develop for assessing the safety and efficiency of cell-based therapies for future human application and have included positron emission tomography (PET), bioluminescence imaging (BLI), and magnetic resonance imaging (MRI) [11–16].…”