Kimberly, W.T., Zheng, J.B., Guenette, S.Y.,
and Selkoe, D.J. (2001). J. Biol. Chem. 276,
Kimberly, W.T., LaVoie, M.J., Ostaszewski,
B.L., Ye, W., Wolfe, M.S., and Selkoe, D.J.
(2002). J. Biol. Chem. 277, 35113–35117.
Leem, J.Y., Vijayan, S., Han, P., Cai, D., Ma-
chura, M., Lopes, K.O., Veselits, M.L., Xu, H.,
and Thinakaran, G. (2002). J. Biol. Chem.
Pardossi-Piquard, R., Petit, A., Kawarai, T.,
Sunyach, C., Alves da Costa, C., Vincent, B.,
Ring, S., D’Adamio, L., Shen, J., Muller, U.,
et al. (2005). Neuron 46, 541–554.
Seiffert, D., Bradley, J.D., Rominger, C.M., Ro-
minger, D.H., Yang, F., Meredith, J.E., Jr., Wang,
Q., Roach, A.H., Thompson, L.A., Spitz, S.M.,
et al. (2000). J. Biol. Chem. 275, 34086–34091.
Welches, W.R., Brosnihan, K.B., and Ferrario,
C.M. (1993). Life Sci. 52, 1461–1480.
Zhang, Z., Nadeau, P., Song, W., Donoviel, D.,
Yuan, M., Bernstein, A., and Yankner, B.A.
(2000). Nat. Cell Biol. 2, 463–465.
Response to Correspondence: Pardossi-Piquard
et al., ‘‘Presenilin-Dependent Transcriptional
Control of the Ab-Degrading Enzyme Neprilysin by
Intracellular Domains of bAPP and APLP.’’
Neuron 46, 541–554
Raphae ¨lle Pardossi-Piquard,1Julie Dunys,1Toshitaka Kawarai,2Claire Sunyach,1Cristine Alves da Costa,1
Bruno Vincent,1Jean Se ´valle,1Sanjay Pimplikar,3Peter St George-Hyslop,2and Fre ´de ´ric Checler1,*
1IPMC, UMR6097 CNRS/UNSA, Equipe labellise ´e FRM, 660 Route des Lucioles, 06560 France
2Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, M5S 3H2 Canada
3Department of Pathology and Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
We recently established that neprilysin
(NEP), one of the putative amyloid
b-peptide (Ab)-degrading enzymes,
AICDs, the C-terminal fragments of
(bAPP/APLP) that are generated by
presenilin (PS)-dependent g- and 3-
secretase activities (Pardossi-Piquard
et al., 2005). Chen and Selkoe now re-
port lack of evidence of NEP upregula-
tion by PS-dependent g-secretase. To
explore the reasons for this difference,
we have repeated several experi-
ments, conducted new experiments,
and carefully examined the data pre-
sented by Chen and Selkoe. These
analyses reveal that (1) there is signifi-
cant consensus in key experimental
data; (2) several of Chen and Selkoe’s
negative conclusions are overreach-
ing, arising from a crucial conceptual
pelling, independent data from experi-
ments in nicastrin null cells and in brain
from transgenic mice overexpressing
AICD that support the notion that pre-
senilin complexes and AICD modulate
inducible NEP expression.
Results and Discussion
There is consensus on several impor-
tant points. Both groups find that NEP
expression is dramatically reduced in
mouse embryonic fibroblasts (MEFs)
(Figures 1D and 1E in Pardossi-Pi-
quard et al., 2005; Figures 1A and 1B
in this paper; Figure 1C in Chen and
Selkoe, 2007). Both groups find mod-
est reductions (%25%) in NEP expres-
sion in PS1?/?:PS2?/?double-knock-
out BD8 blastocyst cells (Figures 1F
and 1G in Pardossi-Piquard et al.,
2005; Figure 1A in Chen and Selkoe,
2007). Both groups observe either
modest or no consistent change in
NEP expression in single-knockout
PS1?/?, PS2?/?, APP?/?, and APLP-
2?/?MEFs (Figures 3C and 6C in
Pardossi-Piquard et al., 2005; Figures
1A and 1B in this paper; Figures 1C
and 4C in Chen and Selkoe, 2007).
Repetition of several of our experi-
ments using different MEF cell lines
and different anti-NEP antibodies re-
veals that the results are unchanged
(Figures 1A and 1B). This argues
against an artifact arising from labora-
tory error or from differences in clones.
We have also pursued additional
experiments, both of which strongly
support the validity of our initial report.
First, we investigated NEP activity,
protein, and mRNA levels in nicastrin
knockout MEFs (NCT?/?), which do
not form functional presenilin com-
plexes and which have no g-secretase
activity (Yu et al., 2000). NEP expres-
sion, NEP activity, and NEP mRNA
levels were all dramatically reduced
in nicastrin knockout MEFs (NCT?/?)
(Pardossi-Piquard et al., 2006) (Fig-
ure 1C). However, NEP expression is
restored in these NCT?/?MEFs by
Neuron 53, February 15, 2007 ª2007 Elsevier Inc.