Browsing by Author "Davis, EE"

Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Individuals with mutations in XPNPEP3, which encodes a mitochondrial protein, develop a nephronophthisis-like nephropathy.
    (J Clin Invest, 2010-03) O'Toole, JF; Liu, Y; Davis, EE; Westlake, CJ; Attanasio, M; Otto, EA; Seelow, D; Nurnberg, G; Becker, C; Nuutinen, M; Kärppä, M; Ignatius, J; Uusimaa, J; Pakanen, S; Jaakkola, E; van den Heuvel, LP; Fehrenbach, H; Wiggins, R; Goyal, M; Zhou, W; Wolf, MT; Wise, E; Helou, J; Allen, SJ; Murga Zamalloa, CA; Ashraf, S; Chaki, M; Heeringa, S; Chernin, G; Hoskins, BE; Chaib, H; Gleeson, J; Kusakabe, T; Suzuki, T; Isaac, RE; Quarmby, LM; Tennant, B; Fujioka, H; Tuominen, H; Hassinen, I; Lohi, H; van Houten, JL; Rotig, A; Sayer, JA; Rolinski, B; Freisinger, P; Madhavan, SM; Herzer, M; Madignier, F; Prokisch, H; Nurnberg, P; Jackson, PK; Jackson, P; Khanna, H; Katsanis, N; Hildebrandt, F
    The autosomal recessive kidney disease nephronophthisis (NPHP) constitutes the most frequent genetic cause of terminal renal failure in the first 3 decades of life. Ten causative genes (NPHP1-NPHP9 and NPHP11), whose products localize to the primary cilia-centrosome complex, support the unifying concept that cystic kidney diseases are "ciliopathies". Using genome-wide homozygosity mapping, we report here what we believe to be a new locus (NPHP-like 1 [NPHPL1]) for an NPHP-like nephropathy. In 2 families with an NPHP-like phenotype, we detected homozygous frameshift and splice-site mutations, respectively, in the X-prolyl aminopeptidase 3 (XPNPEP3) gene. In contrast to all known NPHP proteins, XPNPEP3 localizes to mitochondria of renal cells. However, in vivo analyses also revealed a likely cilia-related function; suppression of zebrafish xpnpep3 phenocopied the developmental phenotypes of ciliopathy morphants, and this effect was rescued by human XPNPEP3 that was devoid of a mitochondrial localization signal. Consistent with a role for XPNPEP3 in ciliary function, several ciliary cystogenic proteins were found to be XPNPEP3 substrates, for which resistance to N-terminal proline cleavage resulted in attenuated protein function in vivo in zebrafish. Our data highlight an emerging link between mitochondria and ciliary dysfunction, and suggest that further understanding the enzymatic activity and substrates of XPNPEP3 will illuminate novel cystogenic pathways.
  • Thumbnail Image
    ItemOpen Access
    Rapid and efficient generation of transgene-free iPSC from a small volume of cryopreserved blood
    (Stem Cell Reviews and Reports, 2015) Zhou, H; Martinez, H; Sun, B; Li, A; Zimmer, M; Katsanis, N; Davis, EE; Kurtzberg, J; Lipnick, S; Noggle, S; Rao, M; Chang, S
    © The Author(s) 2015.Human peripheral blood and umbilical cord blood represent attractive sources of cells for reprogramming to induced pluripotent stem cells (iPSCs). However, to date, most of the blood-derived iPSCs were generated using either integrating methods or starting from T-lymphocytes that have genomic rearrangements thus bearing uncertain consequences when using iPSC-derived lineages for disease modeling and cell therapies. Recently, both peripheral blood and cord blood cells have been reprogrammed into transgene-free iPSC using the Sendai viral vector. Here we demonstrate that peripheral blood can be utilized formedium-throughput iPSC production without the need to maintain cell culture prior to reprogramming induction. Cell reprogramming can also be accomplished with as little as 3000 previously cryopreserved cord blood cells under feeder-free and chemically defined Xeno-free conditions that are compliant with standard Good Manufacturing Practice (GMP) regulations. The first iPSC colonies appear 2–3 weeks faster in comparison to previous reports. Notably, these peripheral blood- and cord bloodderived iPSCs are free of detectable immunoglobulin heavy chain (IGH) and T cell receptor (TCR) gene rearrangements, suggesting they did not originate from B- or T- lymphoid cells. The iPSCs are pluripotent as evaluated by the scorecard assay and in vitro multi lineage functional cell differentiation. Our data show that small volumes of cryopreserved peripheral blood or cord blood cells can be reprogrammed efficiently at a convenient, cost effective and scalable way. In summary, our method expands the reprogramming potential of limited or archived samples either stored at blood banks or obtained from pediatric populations that cannot easily provide large quantities of peripheral blood or a skin biopsy.