Uromodulin and kidney disease: a new entry for an old molecule

1
Uromodulin and kidney disease a new entry for
an old molecule
MCKD/FJHN Italian Consortium Gian Marco
Ghiggeri Lyon ESPN 2008

2
Uromodulin

• Initially described by Tamm and Horsfall in 1950

• Most abundant protein in human urine (50-100
  mg/day)

Exclusively expressed in TAL and DCT
Glomerulus
proximal tubule
Collecting duct
distal tubule
Henles loop
descending limb
ascending limb
Dahan et al., J Am Soc Nephrol 2003
3
4
9
Non linear pH
150
kDa
5
4
Tamm Horsfall Glycoprotein
Igor TAMM and Frank L. Horsfall. Characterization
and separation of an inhibitor of viral
hemagglutination present in urine. Proc Soc Exp
Biol Med. 1950 May74(1)106-8
5
Uromodulin structure
Y
Y
Y
Y
Y
Y
Y
ZP domain
I
III
D8C
II
31
334
585
640
22
281
614

• ZP is a large domain, containing around 260 aa,
  including 8(10) conserved Cys residues, which are
  involved in disulphide bond formation.
• Found in a variety of receptor-like eukaryotic
  glycoproteins (mouse sperm receptors ZP1, ZP2,
  ZP3 alpha-tectorin)
• ZP domain proteins almost invariably contain
  single transmembrane domains or GPI anchors that
  are missing from the secreted mature proteins
• Responsible for the ability of ZP domain proteins
  to assemble into filaments

Jovine et al.,Nat Cell Biol 2002
6
Uromodulin structure
Y
Y
Y
Y
Y
Y
Y
ZP domain
I
III
D8C
II
31
640
22
334
585
281
614
cf 568 EVYLCDIINEKCKPTCSGTRFRSGGIIDQSRVLNL
GPITRKNVQAVVSRAASSSLGFLKVCLPLLLSATLTLMFQ 642
bt 569 EVYLCDTVNEKCRPTCPETRFRSGSIIDQTRVLNLGPITR
KGGQAAMSRAAPSSLGLLQVWLPLLLSATLTLMSP 643 hs
567 EVYLCDTMNEKCKPTCSGTRFRSGSVIDQSRVLNLGPITRKGVQA
TVSRAFSS-LGLLKVWLPLLLSATLTLTFQ 640 mm 568
EVYLCDSTSEQCKPTCSGTRFRSGNFIDQTRVLNLGPITRQGVQASVSKA
ASSNLRLLSIWLLLFPSATLIFMVQ 642 rn 570
EVYLCDTMSEQCKPTCSGTRYRSGNFIDQTRVLNLGPITRQGVQASVSKA
ASSNLGFLSIWLLLFLSATLTLMVH 644
.. ...
. .
GPI anchor
Santambrogio et al.,Biochem Biophys Res Comm 2008
7
Uromodulin function

• Urothelial defence against infections
• Urothelial defence against calcium oxalate
  crystals-induced damage
• Urothelial defence against ischemic damage
• Water / salt balance in TAL and DCT

Mo et al, Am J Physiol Renal Physiol, 2003
Mo et al, Kidney Int, 2004
El-Achkar et al, JASN, 2008
Wiggins et al, Clin Chim Acta, 1987
8
Uromodulin Related Diseases
9
(No Transcript)
10
ALLELISM of MCKD, FJHN and GCKD

• MCKD
• - Dominant tubulo-interstitial nephritis
• - Hypostenuria, ESRD, Medullary cysts
• - Hyperuricemia and gout
• FJHN
• - Phenotypic similarity with MCKD (no medullary
  cysts)
• - Tubulo Interstitial Nephropathy,
• - Hyperuricemia and gout
• GCKD
• - Glomerular cysts dilatation of Bowmans space
• - Sporadic or dominant disorder
• - Also part of metabolic syndrome (MODY5
  HNF-1beta mut.)

11
Summary of UMOD published mutations
Exon 4 Exon 5 98 mutations (42/43)
43 mutations
26 Cys-affecting
1 Gly to Cys
13 other missense
3 in frame deletions
12
MCKD/FJHN
GCKD
13
Normal
MCKD
14
GCKD
15
MCKD/FJHN kidney biopsy
Dr. Vivette DAgati, Dept of Pathology, Columbia
Univ
16
Urinary uromodulin is reduced in MCKD2/FJHN
patients
MCKD1
1
2
1
2
3
4
5
6
7
1
2
3
4
5
6
7
8
9
10
11
12
13
1
2
3
4
6
5

• Uromodulin urinary excretion in affected
  individuals
• Amount of daily excreted uromodulin is 15 to 30
  fold decreased
• (Bleyer et al., Kidney Int 2004)
• Excreted uromodulin is wild type only
• (Dahan et al., J Am Soc Nephrol, 2003)

17
MOLECULAR PATHOGENESIS

• In vitro studies

18
WT
C148W
Unpermeabilized HEK293 after transfection (6 hrs)
19
Mutant uromodulin is retained in the ER
20
ANIMAL MODELS THP -/-

• Are more prone to develop
• urinary tract infection.
• Do no develop MCKD
• Knock-in mice ?

Raffi et al Kidney In, 2006
21
Mechanisms

• Urine concentration defect interaction with
• 
  ROMK
• Hyperuricemia idem
• TI fibrosis ?
• Cyst formation ?

22
UAKD Uromodulin Associated Kidney Diseases
- Chr 17q12 (HNF1-beta) - Chr 1q21 ? - Chr
1q41 ?
23
Atypical familial juvenile hyperuricemic
nephropathy associated with a HNF1B mutation
Bingham el al, Kidney Int 2003
24
Renal-specific inactivation of HNF1B
UMOD can be considered as direct transcriptional
targets of HNF1B Gresh et al, EMBO J, 2004
25
UROMODULIN ASSOCIATED KIDNEY DISEASE
Control
Umod Mutation
?
Linkage 1q41
Hodanova et al Kidney Int 2005
26
CONCLUSIONS

• The re-discovery of an old actor
• such as Uromodilun offers the opportunity to
  open a new area of research on renal fibrosis
  that may lead to important advancements

27

• Thank You!

28
MCKD/FJHN Italian Consortium
G. Gaslini Institute, Genoa Gianluca Caridi Gian
Marco Ghiggeri Clinical analysis Molecular
analysis
University of Turin Mario De Marchi Antonio
Amoroso Molecular analysis
University of Brescia Francesco Scolari Clinical
analysis Kidney pathology
DTI, Dibit-HSR, Milan Luca Rampoldi Cellular and
animal models Linkage analysis
University of Padua Luisa Murer Kidney pathology