Astrocyte-derived lactoferrin reduces Aβ burden by promoting the
interaction of p38 and PP2A in APP/PS1 transgenic mice
Yong-Gang Fan1, #, Chuang Guo2, #,
Ling-Xiao Zhao1, Ri-Le Ge1,
Zhong-Qiu Pang2, Da-Long He1, Hang
Ren1, Yan-Hui Zhang1, Zhan-You
Wang1, *
1 Key Laboratory of Medical Cell Biology of Ministry
of Education, Key Laboratory of Major Chronic Diseases of Nervous System
of Liaoning Province, Health Sciences Institute of China Medical
University, Shenyang, 110122, China.
2 College of Life and Health Sciences, Northeastern
University, Shenyang, 110169, China.
# These authors contributed equally to this work.
*Correspondence and requests for materials should be
addressed to Z.Y.W. (email:
wangzy@cmu.edu.cn).
Running title: Lactoferrin against Alzheimer’s disease
Background and Purpose: Overexpression
of
astrocytic
lactoferrin (Lf) was observed in the brains of Alzheimer’s disease (AD)
patients, whereas the role of
astrocytic Lf in AD progression remains unexplored. In this study, we
aimed to evaluate the effects of astrocytic Lf on AD progression.
Experimental Approach:The APP/PS1 mice with astrocytes
overexpressing human Lf were developed to evaluate the effects of
astrocytic Lf on AD progression, and the N2a-sw cells were employed to
further uncover the mechanism of astrocytic Lf on β-amyloid (Aβ)
production.
Key Results: Astrocytic Lf overexpression increased protein
phosphatase 2A (PP2A) activity, and reduced amyloid precursor protein
(APP) phosphorylation, Aβ burden and tau hyperphosphorylation in APP/PS1
mice. Mechanistically, astrocytic Lf overexpression promoted the
astrocytic Lf secretion into neurons in APP/PS1 mice, and the
conditional medium from astrocytes overexpressing Lf inhibited the
p-APP(Thr668) expression in N2a-sw cells. Furthermore, the recombinant
human Lf (hLf) also significantly enhanced PP2A activity and inhibited
p-APP expression, while inhibitions of p38 or PP2A activities abrogated
the hLf-induced p-APP downregulation in N2a-sw cells. Additionally, hLf
promoted the interaction of p38 and PP2A via p38 activation, thereby
enhancing PP2A activity; and low-density lipoprotein receptor-related
protein 1 (LRP1) knockdown significantly reversed the hLf-induced p38
activation and p-APP
downregulation.
Conclusions and Implications: Our data suggested that
astrocytic Lf promoted neuronal p38 activation via targeting to LRP1,
subsequently promoting p38 binds to PP2A to enhance PP2A activity, which
finally inhibited Aβ production via APP dephosphorylation. Therefore,
promoting astrocytic Lf expression may be a potential strategy against
AD.