Deletion of hypoxia‐responsive microRNA‐210 results in a sex‐specific decrease in nephron number

Abstract

Low nephron number results in an increased risk of developing hypertension and chronic kidney disease. Intrauterine growth restriction is associated with a nephron deficit in humans, and is commonly caused by placental insufficiency, which results in fetal hypoxia. The underlying mechanisms by which hypoxia impacts kidney development are poorly understood. microRNA‐210 is the most consistently induced microRNA in hypoxia and is known to promote cell survival in a hypoxic environment. In this study, the role of microRNA‐210 in kidney development was evaluated using a global microRNA‐210 knockout mouse. A male‐specific 35% nephron deficit in microRNA‐210 knockout mice was observed. Wnt/β‐catenin signaling, a pathway crucial for nephron differentiation, was misregulated in male kidneys with increased expression of the canonical Wnt target lymphoid enhancer binding factor 1. This coincided with increased expression of caspase‐8‐associated protein 2, a known microRNA‐210 target and apoptosis signal transducer. Together, these data are consistent with a sex‐specific requirement for microRNA‐210 in kidney development.

Chromatin accessibility and microRNA expression in nephron progenitor cells during kidney development

“…The cells were washed and resuspended in ice-cold isolation buffer consisting of 2% FBS in PBS, then incubated with magnetic beads (Dynabeads FlowComp Flexi kit, ThermoFisher 11061D) biotinylated to antibodies for Integrin alpha 8 (Itgα8, R&D Systems AF4076) using the DSB-X Biotin Protein Labeling Kit (ThermoFisher D-20655). Nephron progenitors bound to these beads were isolated as previously published (Hemker et al, 2020) and pooled across kidneys for each sample. An aliquot of 50,000 nephron progenitor cells was immediately processed through the chromatin accessibility library preparation protocol (see below), and total RNA was extracted from the remaining cell suspension using the Qiagen miRNeasy Mini Kit (Qiagen 217004).…”

“…miRNA are short, non-coding RNA molecules that target messenger-RNA transcripts (mRNA) for decreased translation or enhanced degradation, in both cases via the RNA-induced silencing complex (RISC) (Bartel, 2009). Loss of miRNA processing in nephron progenitors results in premature depletion of the nephron progenitor population (Ho et al, 2011); for instance, global removal of the hypoxia-responsive miR-210 causes a significant decrease in nephron endowment in male mice (Hemker et al, 2020), and deletion of the miR-17∼92 cluster in nephron progenitors impairs progenitor proliferation and reduces nephron endowment (Marrone et al, 2014). Further, the protein Lin28b is a known repressor of the let-7 family of miRNAs (Heo et al, 2008), and its expression in nephron progenitors decreases as nephrogenesis proceeds.…”

MicroRNAs in kidney development and disease

“…Using a human embryonic stem cell model, Bantounas et al showed that inhibition of the miR-199a~214 cluster results in dysmorphic glomeruli, aberrant proximal tubules, decreased WT1 expression, and increased interstitial capillaries in kidney-like organoids (82). Interestingly, global deletion of hypoxia-responsive miR-210 results in a male-specific nephron deficit (83). For example, Figure 2.…”

The miR-199a/214 Cluster Controls Nephrogenesis and Vascularization in a Human Embryonic Stem Cell Model

“…miR- 19b in the cluster suppresses the cystic fibrosis transmembrane conductance regulator ( Cftr ) gene, in murine nephron progenitors, and misregulation of this gene causes changes in proliferation of the progenitors ( Marrone et al., 2014 ; Phua et al., 2019 ). Knockout studies revealed a requirement for miR-210 through its regulation of Wnt signaling in the development of normal nephron numbers in male mice ( Hemker et al., 2020 ). An anti-inflammatory/anti-cystic role for miR-214 in autosomal dominant polycystic kidney disease has also been identified ( Lakhia et al., 2020 ).…”