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. 2019 Mar 1;6(1):ENEURO.0242-18.2019.
doi: 10.1523/ENEURO.0242-18.2019. eCollection Jan-Feb 2019.

The Disease-Associated Chaperone FKBP51 Impairs Cognitive Function by Accelerating AMPA Receptor Recycling

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Free PMC article

The Disease-Associated Chaperone FKBP51 Impairs Cognitive Function by Accelerating AMPA Receptor Recycling

Laura J Blair et al. eNeuro. .
Free PMC article

Abstract

Increased expression of the FK506-binding protein 5 (FKBP5) gene has been associated with a number of diseases, but most prominently in connection to psychiatric illnesses. Many of these psychiatric disorders present with dementia and other cognitive deficits, but a direct connection between these issues and alterations in FKBP5 remains unclear. We generated a novel transgenic mouse to selectively overexpress FKBP5, which encodes the FKBP51 protein, in the corticolimbic system, which had no overt effects on gross body weight, motor ability, or general anxiety. Instead, we found that overexpression of FKBP51 impaired long-term depression (LTD) as well as spatial reversal learning and memory, suggesting a role in glutamate receptor regulation. Indeed, FKBP51 altered the association of heat-shock protein 90 (Hsp90) with AMPA receptors, which was accompanied by an accelerated rate of AMPA recycling. In this way, the chaperone system is critical in triage decisions for AMPA receptor trafficking. Imbalance in the chaperone system may manifest in impairments in both inhibitory learning and cognitive function. These findings uncover an unexpected and essential mechanism for learning and memory that is controlled by the psychiatric risk factor FKBP5.

Keywords: AMPA receptor; FKBP5; Hsp90; chaperone.

Figures

Figure 1.
Figure 1.
Detailed schematic and validation of the FKBP5 TRE transgene. A, To allow for site-directed, single copy insertion into the mouse genome in chromosome 11, the transgenic construct contained flanking attB sites via a PhiC31 integrase. The downstream Mp1 poly A tail will help maintain stable expression. To drive high expression, the transgenic construct included a tetracycline-response element (TRE) promoter made of seven repeats of the tetracycline operators used to drive high expression of the singly inserted FKBP5 gene in the presence of the tTA, and a weak minimal CMV promoter which produces low basal expression. B, Western blotting from HEK293T cells transfected with increasing amounts of FKBP5 TRE plasmid, as indicated, for 48 h. C, HEK293T cells were transfected with the indicated amounts of FKBP5 TRE and tTA plasmid, to ensure the tTA would drive high FKBP51 expression.
Figure 2.
Figure 2.
FKBP51 expression and distribution in rTgFKBP5 mice. A, Expression of human and mouse FKBP5 in rTgFKBP5 mice expressed as fold change ± SEM compared to WT mice using qPCR; ***p < 0.001 by t test (N = 10) with three technical replicates. B, Western blotting showing FKBP51 levels in the hippocampus from rTgFKBP5, WT, FKBP5, and tTA mice. C, Western blotting showing levels of FKBP51 levels in the rTgFKBP5 hippocampus from 1 to 10 µg of protein loaded compared to 50 µg of protein from WT or FKBP51 mice. GAPDH levels are shown to confirm protein load. See Extended Data Figure 2-1 for more information on the antibody. D, 20× images of anti-FKBP51 staining from rTgFKBP5 mice. The entorhinal cortex (ECX), anterior cortex (ACX), CA1, CA3, and dentate gyrus (DG) are labeled. E, 20× images of anti-FKBP51 staining from rTgFKBP5 mice in the CA1, CA3, DG, ECX, and ACX. Scale bar = 100 µm; 10 µm (inset). F, Western blotting showing FKBP51 levels in the hippocampus, striatum, ACX, posterior cortex (PCX), interbrain, thalamus and hypothalamus, and cerebellum of a rTgFKBP5 mouse. G, Quantitation of FKBP51 proteins levels throughout the hippocampus (HPC), striatum (STR), ACX, PCX, interbrain, thalamus and hypothalamus (INTER), and cerebellum (CER), of rTgFKBP5 mice from multiple exposures.
Figure 3.
Figure 3.
FKBP51 overexpression does not alter basal weight, motor ability, general anxiety, or depression-like behavior but has modest effects on pleasure seeking behavior. A, Whole body weight for rTgFKBP5, WT, and tTA mice was recorded at the indicated time points N ≥ 7/genotype at each time point. B, Time on the rotarod apparatus in rTgFKBP5 (N = 16), WT (N = 22), and tTA (N = 20) mice. Total distance traveled (C) and distance traveled (D) in the center in the open field task was measured for rTgFKBP5 (N = 16), WT (N = 22), and tTA (N = 19) mice. Total immobility time was recorded over 360 s of the (E) TST and (F) FST. G, Sucrose preference was measured in rTgFKBP5 (N = 16), WT (N = 22), and tTA (N = 20) mice. Consumption was measured by the difference in the weight of bottles filled with sucrose water versus tap water. Sucrose preference percentage ± SEM was determined by the amount (g) of sucrose water consumed versus the amount of total water consumed over the 2-h task. See Extended Data Figure 3-1 for sex differences. *p = 0.0219.
Figure 4.
Figure 4.
rTgFKBP5 exhibit reversal deficits MWM reversal learning and memory. A, Escape latencies (s) ± SEM from rTgFKBP5, WT, and tTA control mice (N = 10/genotype) over 4 d of training in the MWM behavioral task. Two-way ANOVA of entire training. The probe trial ± SEM from (B) rTgFKBP5, WT, and tTA mice 24 h after the last training session; ***p < 0.001, **p < 0.01 by one-way ANOVA. C, Escape latencies (s) ± SEM of rTgFKBP5, WT, and tTA mice (N = 10/genotype) trained to find an escape platform in the opposite quadrant of the initial MWM; ***p < 0.001 by two-way ANOVA. D, The reversal probe trial ± SEM from rTgFKBP5, WT, and tTA mice; ***p < 0.001 by one-way ANOVA.
Figure 5.
Figure 5.
FKBP51 overexpression modestly alters LTP induction and maintenance. Ex vivo hippocampal slices from rTgFKBP5 and littermate controls were prepared for LTP testing in the Schaffer collateral pathway. Following a 20-min baseline, slices were stimulated by one-train (A) or four-trains (B) of HFS at 100 Hz to induce LTP. Evoked fEPSPs ± SEM, normalized to baseline, were measured for 60 min following HFS. In the one-train protocol, slices from rTgFKBP5 (N = 5), WT (N = 6), and tTA (N = 5) mice were used. In the four-train protocol, rTgFKBP5 (N = 7), WT (N = 6), and tTA (N = 8) mice were used. Representative traces are shown: 1 (black) indicates baseline, 2 (teal) indicates initial early LTP potentiation in the first 3 min following potentiation, and 3 (gray) indicates late LTP in the last 3 min of recording. *p < 0.0001 by one-way ANOVA with Tukey’s Multiple Comparison’s test of the last 5 minutes. ***p < 0.0001 by two-way ANOVA.
Figure 6.
Figure 6.
FKBP51 overexpression alters basal AMPA receptor signaling. Following 10 min of consistent response to voltage stimulus, threshold voltage for evoking a fEPSP was measured. Voltage was progressively increased at a rate of 0.5 mV until the maximum fEPSP was reached. The absolute I-O curves of the (A) presynaptic fiber volley amplitude (mV) ± SEM and (B) postsynaptic fEPSP slope (mV/ms) ± SEM from rTgFKBP5 (N = 15), WT (N = 15), and tTA (N = 19) mice. Significance was determined by two-way ANOVA. C, The I-O curves of the fEPSP slope (mV/ms) ± SEM versus the fiber volley amplitude (mV) ± SEM. Representative traces of the I-O for each genotype are shown with 1 representing fiber volley and 2 representing the fEPSP. D, The PPF from rTgFKBP5 (N = 31), WT (N = 33), and tTA (N = 30) is shown, which is derived from the ratio of the slope of the first peak to the slope of the second peak, over the interstimulus interval (ms). Significance was determined by two-way ANOVA. *p < 0.05, **p < 0.01, ***p < 0.0001 by two-way ANOVA.
Figure 7.
Figure 7.
LTD is impaired in rTgFKBP5 mice. LTD fEPSP (%) ± SEM was induced following 20-min baseline recording in ex vivo slices from rTgFKBP5 (N = 9), WT (N = 9), and tTA (N = 10) mice by 900 pulses of low-frequency (3 Hz) stimulation. Representative traces are shown: 1 (black) indicates baseline, 2 (teal) indicates early LTD, and 3 (gray) indicates late LTD; ***p < 0.001 determined by two-way ANOVA.
Figure 8.
Figure 8.
FKBP51/Hsp90 bind to GluR1-type AMPA receptors to regulate trafficking. A, Representative Western blottings form biotinylation assays of receptor endocytosis was performed on ex vivo slices, as described in Materials and Methods, rTgFKBP5 (N = 4; n = 8), WT (N = 2; n = 8), and tTA (N = 2; n = 8). Following labeling with Sulfo-NHS-SS biotin and chemical LTD (20 µM NMDA; 5 min) treatment, receptors were permitted to externalize at 30°C for the indicated times. B, The quantification ± SEM of multiple acquisitions is shown for GluR1. C, Representative Western blottings from anti-GluR1 co-immunoprecipitations and corresponding inputs from control and rTgFKBP5 mice immunoblotted as indicated. rTgFKBP5 (N = 2), WT (N = 2), and tTA (N = 2) total from two independent experiments. D, Representative Western blottings of anti-GluR1 co-immunoprecipitations and corresponding inputs from HEK293T cells transfected with GluR1 and FKBP51 or empty vector (EV) for 48 h were immunoblotted with antibodies as indicated. Just before harvest, cells were treated with 100 µM AMPA or PBS for 10 min to induce GluR1 receptor internalization. *p = 0.0286 by t-test of this time point. **p < 0.001 by two-way ANOVA.
Figure 9.
Figure 9.
Working schematic of FKBP51/Hsp90 regulation of AMPA receptor recycling. Upon LTD stimulation, AMPA receptors are (1) moved away from the synapse and (2) internalized, following internalization either degraded through (3) macroautophagy or (4) recycled back to the membrane. LTD is expressed when the rate of internalization is greater than the rate of exocytosis. In the presence of high levels of FKBP51, Hsp90 binds to GluR1 and drives more AMPA receptors to be recycled back to the membrane.

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References

    1. Anggono V, Huganir RL (2012) Regulation of AMPA receptor trafficking and synaptic plasticity. Curr Opin Neurobiol 22:461–469. 10.1016/j.conb.2011.12.006 - DOI - PMC - PubMed
    1. Attwood BK, Bourgognon JM, Patel S, Mucha M, Schiavon E, Skrzypiec AE, Young KW, Shiosaka S, Korostynski M, Piechota M, Przewlocki R, Pawlak R (2011) Neuropsin cleaves EphB2 in the amygdala to control anxiety. Nature 473:372–375. 10.1038/nature09938 - DOI - PMC - PubMed
    1. Bailey KR, Crawley JN (2009) Anxiety-related behaviors in mice In: Methods of behavior analysis in neuroscience (Buccafusco JJ, editor. , ed), Ed 2 Boca Raton, FL: CRC Press/Taylor & Francis.
    1. Bevilacqua L, Carli V, Sarchiapone M, George DK, Goldman D, Roy A, Enoch MA (2012) Interaction between FKBP5 and childhood trauma and risk of aggressive behavior. Arch Gen Psychiatry 69:62–70. 10.1001/archgenpsychiatry.2011.152 - DOI - PMC - PubMed
    1. Binder EB, Salyakina D, Lichtner P, Wochnik GM, Ising M, Pütz B, Papiol S, Seaman S, Lucae S, Kohli MA, Nickel T, Künzel HE, Fuchs B, Majer M, Pfennig A, Kern N, Brunner J, Modell S, Baghai T, Deiml T, et al. . (2004) Polymorphisms in FKBP5 are associated with increased recurrence of depressive episodes and rapid response to antidepressant treatment. Nat Genet 36:1319–1325. 10.1038/ng1479 - DOI - PubMed

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