Selective disruption of TLR2-MyD88 interaction inhibits inflammation and attenuates Alzheimer’s pathology
Suresh B. Rangasamy, … , David A. Bennett, Kalipada Pahan
Suresh B. Rangasamy, … , David A. Bennett, Kalipada Pahan
Published July 10, 2018
Citation Information: J Clin Invest. 2018;128(10):4297-4312. https://doi.org/10.1172/JCI96209.
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Research Article Inflammation Neuroscience

Selective disruption of TLR2-MyD88 interaction inhibits inflammation and attenuates Alzheimer’s pathology

Abstract

Induction of TLR2 activation depends on its association with the adapter protein MyD88. We have found that TLR2 and MyD88 levels are elevated in the hippocampus and cortex of patients with Alzheimer’s disease (AD) and in a 5XFAD mouse model of AD. Since there is no specific inhibitor of TLR2, to target induced TLR2 from a therapeutic angle, we engineered a peptide corresponding to the TLR2-interacting domain of MyD88 (TIDM) that binds to the BB loop of only TLR2, and not other TLRs. Interestingly, WT TIDM peptide inhibited microglial activation induced by fibrillar Aβ1-42 and lipoteichoic acid, but not 1-methyl-4-phenylpyridinium, dsRNA, bacterial lipopolysaccharide, flagellin, or CpG DNA. After intranasal administration, WT TIDM peptide reached the hippocampus, reduced hippocampal glial activation, lowered Aβ burden, attenuated neuronal apoptosis, and improved memory and learning in 5XFAD mice. However, WT TIDM peptide was not effective in 5XFAD mice lacking TLR2. In addition to its effects in 5XFAD mice, WT TIDM peptide also suppressed the disease process in mice with experimental allergic encephalomyelitis and collagen-induced arthritis. Therefore, selective targeting of the activated status of 1 component of the innate immune system by WT TIDM peptide may be beneficial in AD as well as other disorders in which TLR2/MyD88 signaling plays a role in disease pathogenesis.

Authors

Suresh B. Rangasamy, Malabendu Jana, Avik Roy, Grant T. Corbett, Madhuchhanda Kundu, Sujyoti Chandra, Susanta Mondal, Sridevi Dasarathi, Elliott J. Mufson, Rama K. Mishra, Chi-Hao Luan, David A. Bennett, Kalipada Pahan

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Figure 3

Selective disruption of TLR2 and MyD88 interaction by WT TIDM.

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Selective disruption of TLR2 and MyD88 interaction by WT TIDM. In silico...
In silico analyses of interactions of WT TIDM with TLR1, TLR4, TLR5, TLR6, TLR7, and TLR9. Rigid-body interaction analyses were performed using the pyDock in silico analysis tool. Complexes of TLR1–WT TIDM (A), TLR4–WT TIDM (B), TLR5–WT TIDM (C), TLR6–WT TIDM (D), TLR7–WT TIDM (E), and TLR9–WT TIDM (F) are shown. (G) BV-2 microglial cells preincubated with WT TIDM and mTIDM peptides for 1 hour were stimulated with 1 μM fibrillar Aβ1-42 (fAβ) under serum-free conditions. After 1 hour, cellular extracts were immunoprecipitated (IP) with an anti-MyD88 antibody, followed by Western blotting of immunoprecipitates for TLR2. As a control, cellular extracts were immunoprecipitated with normal IgG. Input was also immunoblotted (IB) with TLR2 and MyD88. (H) Bands were scanned, and values (TLR2/input) are presented relative to the control (n = 2 replicates/condition in 3 independent experiments). ***P < 0.001; 2-sample t test. Results were analyzed by 2-sample t test. (I) BV-2 microglial cells preincubated with WT TIDM and mTIDM peptides for 1 hour were stimulated with LPS under serum-free condition. After 1 hour, cellular extracts were immunoprecipitated with an anti-MyD88 antibody, followed by Western blotting of immunoprecipitates for TLR4. As a control, cellular extracts were immunoprecipitated with normal IgG. Input was also immunoblotted with TLR4 and MyD88. (J) Bands were scanned, and values (TLR4/input) are presented relative to the control (n = 2 replicates/condition in 3 independent experiments). ***P < 0.001; 2-sample t test. (K) BV-2 microglial cells were transduced with pLenti-cMyc-cTlr2 lentivirions, and 48 hours after transduction, cells were treated with WT TIDM and mTIDM for 1 hour, followed by stimulation with fibrillar Aβ1-42. After 1 hour, cellular extracts were immunoprecipitated with anti-MyD88 antibody, followed by Western blotting of immunoprecipitates for cMyc. Immunodepleted (ID) fractions were also immunoblotted for cMyc as a control. (L) Bands were scanned and values (cMyc/input) presented relative to the control (n = 2 replicates/condition in 3 independent experiments). *P < 0.05 and **P < 0.01; 2-sample t test. Data represent the mean ± SEM.