scholarly journals Restoring GABAergic inhibition rescues memory deficits in a Huntington’s disease mouse model

2018 ◽  
Vol 115 (7) ◽  
pp. E1618-E1626 ◽  
Author(s):  
Zahra Dargaei ◽  
Jee Yoon Bang ◽  
Vivek Mahadevan ◽  
C. Sahara Khademullah ◽  
Simon Bedard ◽  
...  

Huntington’s disease (HD) is classically characterized as a movement disorder, however cognitive impairments precede the motor symptoms by ∼15 y. Based on proteomic and bioinformatic data linking the Huntingtin protein (Htt) and KCC2, which is required for hyperpolarizing GABAergic inhibition, and the important role of inhibition in learning and memory, we hypothesized that aberrant KCC2 function contributes to the hippocampal-associated learning and memory deficits in HD. We discovered that Htt and KCC2 interact in the hippocampi of wild-type and R6/2-HD mice, with a decrease in KCC2 expression in the hippocampus of R6/2 and YAC128 mice. The reduced expression of the Cl−-extruding cotransporter KCC2 is accompanied by an increase in the Cl−-importing cotransporter NKCC1, which together result in excitatory GABA in the hippocampi of HD mice. NKCC1 inhibition by the FDA-approved NKCC1 inhibitor bumetanide abolished the excitatory action of GABA and rescued the performance of R6/2 mice on hippocampal-associated behavioral tests.

2008 ◽  
Vol 412 (2) ◽  
pp. 191-209 ◽  
Author(s):  
Sara Imarisio ◽  
Jenny Carmichael ◽  
Viktor Korolchuk ◽  
Chien-Wen Chen ◽  
Shinji Saiki ◽  
...  

Huntington's disease (HD) is a devastating autosomal dominant neurodegenerative disease caused by a CAG trinucleotide repeat expansion encoding an abnormally long polyglutamine tract in the huntingtin protein. Much has been learnt since the mutation was identified in 1993. We review the functions of wild-type huntingtin. Mutant huntingtin may cause toxicity via a range of different mechanisms. The primary consequence of the mutation is to confer a toxic gain of function on the mutant protein and this may be modified by certain normal activities that are impaired by the mutation. It is likely that the toxicity of mutant huntingtin is revealed after a series of cleavage events leading to the production of N-terminal huntingtin fragment(s) containing the expanded polyglutamine tract. Although aggregation of the mutant protein is a hallmark of the disease, the role of aggregation is complex and the arguments for protective roles of inclusions are discussed. Mutant huntingtin may mediate some of its toxicity in the nucleus by perturbing specific transcriptional pathways. HD may also inhibit mitochondrial function and proteasome activity. Importantly, not all of the effects of mutant huntingtin may be cell-autonomous, and it is possible that abnormalities in neighbouring neurons and glia may also have an impact on connected cells. It is likely that there is still much to learn about mutant huntingtin toxicity, and important insights have already come and may still come from chemical and genetic screens. Importantly, basic biological studies in HD have led to numerous potential therapeutic strategies.


2017 ◽  
Vol 55 (8) ◽  
pp. 6250-6268 ◽  
Author(s):  
Elena Alvarez-Periel ◽  
Mar Puigdellívol ◽  
Verónica Brito ◽  
Florian Plattner ◽  
James A. Bibb ◽  
...  

2014 ◽  
Vol 13 (6) ◽  
pp. 1096-1119 ◽  
Author(s):  
Begona Escribano ◽  
Ana Colin-Gonzalez ◽  
Abel Santamaria ◽  
Isaac Tunez

2021 ◽  
pp. 1-13
Author(s):  
Karen A. Sap ◽  
Arzu Tugce Guler ◽  
Aleksandra Bury ◽  
Dick Dekkers ◽  
Jeroen A.A. Demmers ◽  
...  

Background: Huntington’s disease is a neurodegenerative disorder caused by a CAG expansion in the huntingtin gene, resulting in a polyglutamine expansion in the ubiquitously expressed mutant huntingtin protein. Objective: Here we set out to identify proteins interacting with the full-length wild-type and mutant huntingtin protein in the mice cortex brain region to understand affected biological processes in Huntington’s disease pathology. Methods: Full-length huntingtin with 20 and 140 polyQ repeats were formaldehyde-crosslinked and isolated via their N-terminal Flag-tag from 2-month-old mice brain cortex. Interacting proteins were identified and quantified by label-free liquid chromatography-mass spectrometry (LC-MS/MS). Results: We identified 30 interactors specific for wild-type huntingtin, 14 interactors specific for mutant huntingtin and 14 shared interactors that interacted with both wild-type and mutant huntingtin, including known interactors such as F8a1/Hap40. Syt1, Ykt6, and Snap47, involved in vesicle transport and exocytosis, were among the proteins that interacted specifically with wild-type huntingtin. Various other proteins involved in energy metabolism and mitochondria were also found to associate predominantly with wild-type huntingtin, whereas mutant huntingtin interacted with proteins involved in translation including Mapk3, Eif3h and Eef1a2. Conclusion: Here we identified both shared and specific interactors of wild-type and mutant huntingtin, which are involved in different biological processes including exocytosis, vesicle transport, translation and metabolism. These findings contribute to the understanding of the roles that wild-type and mutant huntingtin play in a variety of cellular processes both in healthy conditions and Huntington’s disease pathology.


2003 ◽  
Vol 12 (3) ◽  
pp. 257-264 ◽  
Author(s):  
R. A. Fricker-Gates ◽  
R. Smith ◽  
J. Muhith ◽  
S. B. Dunnett

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Carmen N. Hernández-Candia ◽  
Sarah Pearce ◽  
Chandra L. Tucker

AbstractDynamic membraneless compartments formed by protein condensates have multifunctional roles in cellular biology. Tools that inducibly trigger condensate formation have been useful for exploring their cellular function, however, there are few tools that provide inducible control over condensate disruption. To address this need we developed DisCo (Disassembly of Condensates), which relies on the use of chemical dimerizers to inducibly recruit a ligand to the condensate-forming protein, triggering condensate dissociation. We demonstrate use of DisCo to disrupt condensates of FUS, associated with amyotrophic lateral sclerosis, and to prevent formation of polyglutamine-containing huntingtin condensates, associated with Huntington’s disease. In addition, we combined DisCo with a tool to induce condensates with light, CRY2olig, achieving bidirectional control of condensate formation and disassembly using orthogonal inputs of light and rapamycin. Our results demonstrate a method to manipulate condensate states that will have broad utility, enabling better understanding of the biological role of condensates in health and disease.


2021 ◽  
pp. 1-8
Author(s):  
Costanza Ferrari Bardile ◽  
Harwin Sidik ◽  
Reynard Quek ◽  
Nur Amirah Binte Mohammad Yusof ◽  
Marta Garcia-Miralles ◽  
...  

Background: The relative contribution of grey matter (GM) and white matter (WM) degeneration to the progressive brain atrophy in Huntington’s disease (HD) has been well studied. The pathology of the spinal cord in HD is comparatively less well documented. Objective: We aim to characterize spinal cord WM abnormalities in a mouse model of HD and evaluate whether selective removal of mutant huntingtin (mHTT) from oligodendroglia rescues these deficits. Methods: Histological assessments were used to determine the area of GM and WM in the spinal cord of 12-month-old BACHD mice, while electron microscopy was used to analyze myelin fibers in the cervical area of the spinal cord. To investigate the impact of inactivation of mHTT in oligodendroglia on these measures, we used the previously described BACHDxNG2Cre mouse line where mHTT is specifically reduced in oligodendrocyte progenitor cells. Results: We show that spinal GM and WM areas are significantly atrophied in HD mice compared to wild-type controls. We further demonstrate that specific reduction of mHTT in oligodendroglial cells rescues the atrophy of spinal cord WM, but not GM, observed in HD mice. Inactivation of mHTT in oligodendroglia had no effect on the density of oligodendroglial cells but enhanced the expression of myelin-related proteins in the spinal cord. Conclusion: Our findings demonstrate that the myelination abnormalities observed in brain WM structures in HD extend to the spinal cord and suggest that specific expression of mHTT in oligodendrocytes contributes to such abnormalities.


Author(s):  
Nicole J. Wayne ◽  
Katherine E. Dembny ◽  
Tyler Pease ◽  
Farrin Saba ◽  
Xiaohong Zhao ◽  
...  

The aggregation of huntingtin fragments with expanded polyglutamine repeat regions (HttpolyQ) that cause Huntington’s disease depends on the presence of a prion with an amyloid conformation in yeast. As a result of this relationship, HttpolyQ aggregation indirectly depends on Hsp104 due to its essential role in prion propagation. We find that HttQ103 aggregation is directly affected by Hsp104 with and without the presence of [ RNQ + ] and [ PSI + ] prions. When we inactivate Hsp104 in the presence of prion, yeast have only one or a few large HttQ103 aggregates rather than numerous smaller aggregates. When we inactivate Hsp104 in the absence of prion, there is no significant aggregation of HttQ103; whereas with active Hsp104, HttQ103 aggregates slowly accumulate due to the severing of spontaneously nucleated aggregates by Hsp104. We do not observe either effect with HttQ103P, which has a polyproline-rich region downstream of the polyglutamine region, because HttQ103P does not spontaneously nucleate and Hsp104 does not efficiently sever the prion-nucleated HttQ103P aggregates. Therefore, the only role of Hsp104 in HttQ103P aggregation is to propagate yeast prion. In conclusion, because Hsp104 efficiently severs the HttQ103 aggregates, but not HttQ103P aggregates, it has a marked effect on the aggregation of HttQ103, but not HttQ103P.


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