Aberrant palmitoylation in Huntington disease

2015 ◽  
Vol 43 (2) ◽  
pp. 205-210 ◽  
Author(s):  
Shaun S. Sanders ◽  
Michael R. Hayden

Huntington disease (HD) is an adult-onset neurodegenerative disease caused by a CAG expansion in the HTT gene. HD is characterized by striatal atrophy and is associated with motor, cognitive and psychiatric deficits. In the presence of the HD mutation, the interactions between huntingtin (HTT) and huntingtin interacting protein 14 (HIP14 or DHHC17) and HIP14-like (DHHC13, a HIP14 orthologue), palmitoyl acyltransferases for HTT, are disturbed, resulting in reduced palmitoylation of HTT. Genetic ablation of either Hip14 or Hip14l recapitulates many features of HD, including striatal atrophy and motor deficits. However, there are no changes in palmitoylation of HTT in either mouse model and, subsequently, the similarities between the phenotypes of these two mouse models and the HD mouse model are believed to result from underpalmitoylation of other HIP14 and HIP14L substrates. HTT acts as a modulator of HIP14 activity such that in the presence of the HD mutation, HIP14 is less active. Consequently, HIP14 substrates are less palmitoylated, leading to neuronal toxicity. This suggests that altered HIP14–HTT and HIP14L–HTT interactions in the presence of the HD mutation reduces palmitoylation and promotes mislocalization of HTT and other HIP14/HIP14L substrates. Ultimately, HD may be, in part, a disease of altered palmitoylation.

2021 ◽  
Author(s):  
Fanny L. Lemarié ◽  
Nicholas S. Caron ◽  
Shaun S. Sanders ◽  
Mandi E. Schmidt ◽  
Yen T.N. Nguyen ◽  
...  

AbstractHuntington disease (HD) is a neurodegenerative disorder caused by a CAG expansion in the HTT gene that codes for an elongated polyglutamine tract in the huntingtin (HTT) protein. HTT is subject to multiple post-translational modifications (PTMs) that regulate its cellular function. Mutating specific PTM sites within mutant HTT (mHTT) in HD mouse models can modulate disease phenotypes, highlighting the key role of HTT PTMs in the pathogenesis of HD. These findings have led to increased interest in developing small molecules to modulate HTT PTMs in order to decrease mHTT toxicity. However, the therapeutic efficacy of pharmacological modulation of HTT PTMs in preclinical HD models remains largely unknown. HTT is palmitoylated at cysteine 214 by the huntingtin-interacting protein 14 (HIP14 or ZDHHC17) and 14-like (HIP14L or ZDHHC13) acyltransferases. Here, we assessed if HTT palmitoylation should be regarded as a therapeutic target to treat HD by (1) investigating palmitoylation dysregulation in rodent and human HD model systems, (2) measuring the impact of mHTT-lowering therapy on brain palmitoylation, and (3) evaluating if HTT palmitoylation can be pharmacologically modulate. We show that palmitoylation of mHTT and some HIP14/HIP14L-substrates is decreased early in multiple HD mouse models, and that aging further reduces HTT palmitoylation. Lowering mHTT in the brain of YAC128 mice is not sufficient to rescue aberrant palmitoylation. However, we demonstrate that mHTT palmitoylation can be normalized in COS-7 cells, in YAC128 cortico-striatal primary neurons and HD patient-derived lymphoblasts using an acyl-protein thioesterase (APT) inhibitor. Moreover, we show that modulating palmitoylation reduces mHTT aggregation and mHTT-induced cytotoxicity in COS-7 cells and YAC128 neurons.HighlightsPalmitoylation of mHTT is reduced in multiple transgenic HD mouse modelsHTT palmitoylation decreases with increasing polyQ length in HD patient cellsmHTT-lowering in mouse brains does not rescue aberrant palmitoylationmHTT palmitoylation in HD patient-derived cells can be rescued via APT inhibitionPromoting palmitoylation reduces mHTT aggregation and cytotoxicity in vitro


Biomedicines ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1160
Author(s):  
Luana Cristina Camargo ◽  
Dominik Honold ◽  
Robert Bauer ◽  
N. Jon Shah ◽  
Karl-Josef Langen ◽  
...  

The contribution of mouse models for basic and translational research at different levels is important to understand neurodegenerative diseases, including tauopathies, by studying the alterations in the corresponding mouse models in detail. Moreover, several studies demonstrated that pathological as well as behavioral changes are influenced by the sex. For this purpose, we performed an in-depth characterization of the behavioral alterations in the transgenic Tau-P301L mouse model. Sex-matched wild type and homozygous Tau-P301L mice were tested in a battery of behavioral tests at different ages. Tau-P301L male mice showed olfactory and motor deficits as well as increased Tau pathology, which was not observed in Tau-P301L female mice. Both Tau-P301L male and female mice had phenotypic alterations in the SHIRPA test battery and cognitive deficits in the novel object recognition test. This study demonstrated that Tau-P301L mice have phenotypic alterations, which are in line with the histological changes and with a sex-dependent performance in those tests. Summarized, the Tau-P301L mouse model shows phenotypic alterations due to the presence of neurofibrillary tangles in the brain.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Kohei Kitagawa ◽  
Kensuke Matsumura ◽  
Masayuki Baba ◽  
Momoka Kondo ◽  
Tomoya Takemoto ◽  
...  

AbstractAutism spectrum disorder (ASD) is a highly prevalent neurodevelopmental disorder characterized by core symptoms of impaired social behavior and communication. Recent studies have suggested that the oxytocin system, which regulates social behavior in mammals, is potentially involved in ASD. Mouse models of ASD provide a useful system for understanding the associations between an impaired oxytocin system and social behavior deficits. However, limited studies have shown the involvement of the oxytocin system in the behavioral phenotypes in mouse models of ASD. We have previously demonstrated that a mouse model that carries the ASD patient-derived de novo mutation in the pogo transposable element derived with zinc finger domain (POGZWT/Q1038R mice), showed ASD-like social behavioral deficits. Here, we have explored whether oxytocin (OXT) administration improves impaired social behavior in POGZWT/Q1038R mice and found that intranasal oxytocin administration effectively restored the impaired social behavior in POGZWT/Q1038R mice. We also found that the expression level of the oxytocin receptor gene (OXTR) was low in POGZWT/Q1038R mice. However, we did not detect significant changes in the number of OXT-expressing neurons between the paraventricular nucleus of POGZWT/Q1038R mice and that of WT mice. A chromatin immunoprecipitation assay revealed that POGZ binds to the promoter region of OXTR and is involved in the transcriptional regulation of OXTR. In summary, our study demonstrate that the pathogenic mutation in the POGZ, a high-confidence ASD gene, impairs the oxytocin system and social behavior in mice, providing insights into the development of oxytocin-based therapeutics for ASD.


2020 ◽  
Vol 22 (1) ◽  
pp. 52
Author(s):  
Mirja Koch ◽  
Constanze Scheel ◽  
Hongwei Ma ◽  
Fan Yang ◽  
Michael Stadlmeier ◽  
...  

Mutations in the CNGA3 gene, which encodes the A subunit of the cyclic guanosine monophosphate (cGMP)-gated cation channel in cone photoreceptor outer segments, cause total colour blindness, also referred to as achromatopsia. Cones lacking this channel protein are non-functional, accumulate high levels of the second messenger cGMP and degenerate over time after induction of ER stress. The cell death mechanisms that lead to loss of affected cones are only partially understood. Here, we explored the disease mechanisms in the Cnga3 knockout (KO) mouse model of achromatopsia. We found that another important effector of cGMP, the cGMP-dependent protein kinase 2 (Prkg2) is crucially involved in cGMP cytotoxicity of cones in Cnga3 KO mice. Virus-mediated knockdown or genetic ablation of Prkg2 in Cnga3 KO mice counteracted degeneration and preserved the number of cones. Analysis of markers of endoplasmic reticulum stress and unfolded protein response confirmed that induction of these processes in Cnga3 KO cones also depends on Prkg2. In conclusion, we identified Prkg2 as a novel key mediator of cone photoreceptor degeneration in achromatopsia. Our data suggest that this cGMP mediator could be a novel pharmacological target for future neuroprotective therapies.


Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1372
Author(s):  
Tengrui Shi ◽  
Jianxi Song ◽  
Guanying You ◽  
Yujie Yang ◽  
Qiong Liu ◽  
...  

MsrB1 used to be named selenoprotein R, for it was first identified as a selenocysteine containing protein by searching for the selenocysteine insert sequence (SECIS) in the human genome. Later, it was found that MsrB1 is homologous to PilB in Neisseria gonorrhoeae, which is a methionine sulfoxide reductase (Msr), specifically reducing L-methionine sulfoxide (L-Met-O) in proteins. In humans and mice, four members constitute the Msr family, which are MsrA, MsrB1, MsrB2, and MsrB3. MsrA can reduce free or protein-containing L-Met-O (S), whereas MsrBs can only function on the L-Met-O (R) epimer in proteins. Though there are isomerases existent that could transfer L-Met-O (S) to L-Met-O (R) and vice-versa, the loss of Msr individually results in different phenotypes in mice models. These observations indicate that the function of one Msr cannot be totally complemented by another. Among the mammalian Msrs, MsrB1 is the only selenocysteine-containing protein, and we recently found that loss of MsrB1 perturbs the synaptic plasticity in mice, along with the astrogliosis in their brains. In this review, we summarized the effects resulting from Msr deficiency and the bioactivity of selenium in the central nervous system, especially those that we learned from the MsrB1 knockout mouse model. We hope it will be helpful in better understanding how the trace element selenium participates in the reduction of L-Met-O and becomes involved in neurobiology.


Sign in / Sign up

Export Citation Format

Share Document