scholarly journals Protein farnesylation is upregulated in Alzheimer’s human brains and neuron-specific suppression of farnesyltransferase mitigates pathogenic processes in Alzheimer’s model mice

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Angela Jeong ◽  
Shaowu Cheng ◽  
Rui Zhong ◽  
David A. Bennett ◽  
Martin O. Bergö ◽  
...  

AbstractThe pathogenic mechanisms underlying the development of Alzheimer’s disease (AD) remain elusive and to date there are no effective prevention or treatment for AD. Farnesyltransferase (FT) catalyzes a key posttranslational modification process called farnesylation, in which the isoprenoid farnesyl pyrophosphate is attached to target proteins, facilitating their membrane localization and their interactions with downstream effectors. Farnesylated proteins, including the Ras superfamily of small GTPases, are involved in regulating diverse physiological and pathological processes. Emerging evidence suggests that isoprenoids and farnesylated proteins may play an important role in the pathogenesis of AD. However, the dynamics of FT and protein farnesylation in human brains and the specific role of neuronal FT in the pathogenic progression of AD are not known. Here, using postmortem brain tissue from individuals with no cognitive impairment (NCI), mild cognitive impairment (MCI), or Alzheimer’s dementia, we found that the levels of FT and membrane-associated H-Ras, an exclusively farnesylated protein, and its downstream effector ERK were markedly increased in AD and MCI compared with NCI. To elucidate the specific role of neuronal FT in AD pathogenesis, we generated the transgenic AD model APP/PS1 mice with forebrain neuron-specific FT knockout, followed by a battery of behavioral assessments, biochemical assays, and unbiased transcriptomic analysis. Our results showed that the neuronal FT deletion mitigates memory impairment and amyloid neuropathology in APP/PS1 mice through suppressing amyloid generation and reversing the pathogenic hyperactivation of mTORC1 signaling. These findings suggest that aberrant upregulation of protein farnesylation is an early driving force in the pathogenic cascade of AD and that targeting FT or its downstream signaling pathways presents a viable therapeutic strategy against AD.

2021 ◽  
Author(s):  
Angela Jeong ◽  
Shaowu Cheng ◽  
Rui Zhong ◽  
David A Bennett ◽  
Martin O Bergö ◽  
...  

The pathogenic mechanisms underlying the development of Alzheimer's disease (AD) remain elusive and to date there are no effective prevention or treatment for AD. Farnesyltransferase (FT) catalyzes a key posttranslational modification process called farnesylation, in which the isoprenoid farnesyl pyrophosphate is attached to target proteins, facilitating their membrane localization and their interactions with downstream effectors. Farnesylated proteins, including the Ras superfamily of small GTPases, are involved in regulating diverse physiological and pathological processes. Emerging evidence suggests that isoprenoids and farnesylated proteins may play an important role in the pathogenesis of AD. However, the dynamics of FT and protein farnesylation in human brains and the specific role of neuronal FT in the pathogenic progression of AD are not known. Here, using postmortem brain tissue from individuals with no cognitive impairment (NCI), mild cognitive impairment (MCI), or Alzheimer's dementia, we found that the levels of FT and membrane-associated H-Ras, an exclusively farnesylated protein, and its downstream effector ERK were markedly increased in AD and MCI compared with NCI. To elucidate the specific role of neuronal FT in AD pathogenesis, we generated the transgenic AD model APP/PS1 mice with forebrain neuron-specific FT knockout, followed by a battery of behavioral assessments, biochemical assays, and unbiased transcriptomic analysis. Our results showed that the neuronal FT deletion mitigates memory impairment and amyloid neuropathology in APP/PS1 mice through suppressing amyloid generation and reversing the pathogenic hyperactivation of mTORC1 signaling. These findings suggest that aberrant upregulation of protein farnesylation is an early driving force in the pathogenic cascade of AD and that targeting FT or its downstream signaling pathways presents a viable therapeutic strategy against AD.


2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
M. S. Suja ◽  
Anita Mahadevan ◽  
S. N. Madhusudana ◽  
S. K. Shankar

To evaluate the role of apoptosis in rabies encephalitis in humans and canines infected with wild-type street virus, in comparison with rodent model infected with street and laboratory passaged CVS strain, we studied postmortem brain tissue from nine humans, six canines infected with street rabies virus, and Swiss albino mice inoculated intramuscularly (IM) and intracerebrally (IC) with street and CVS strains. Encephalitis and high rabies antigen load were prominent in canine and human brains compared to rodents inoculated with street virus. Neuronal apoptosis was detectable only in sucking mice inoculated with CVS strain and minimal in street virus inoculated mice. In a time point study in suckling mice, DNA laddering was noted only terminally (7 days p.i.) following IC inoculation with CVS strain but not with street virus. In weanling and adult mice, apoptosis was restricted to inflammatory cells and absent in neurons similar to human and canine rabies-infected brains. Absence of neuronal apoptosis in wild-type rabies may facilitate intraneuronal survival and replication while apoptosis in inflammatory cells prevents elimination of the virus by abrogation of host inflammatory response.


1997 ◽  
Vol 31 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Stanley V. Catts ◽  
Phillip B. Ward ◽  
Andrew Lloyd ◽  
Xu Feng Huang ◽  
Gavin Dixon ◽  
...  

Objective:There is increasing acceptance that schizophrenia is associated with a generalised disorder in cortical neurodevelopment. The aim of this paper is to review the evidence that this disorder may be accounted for by abnormalities in mechanisms mediated by the main family of excitatory neuroreceptors in cortical brain systems, the N-methyl-D-aspartate (NMDA) glutamatergic receptors. Method:The neurobiological evidence is presented for an abnormality in cortical development related to synaptic pathology in schizophrenia. The unique functions of the NMDA receptor in information processing are described, especially its role in learning and memory, and in neural plasticity and brain development. It is argued that the cellular and molecular mechanisms which underlie learning and memory also govern normal brain development. Studies examining abnormalities in glutamatergic transmission in schizophrenia are reviewed. Results:There is a substantial literature in support of the possibility that NMDA receptor abnormalities may be involved in the neurodevelopmental predisposition to schizophrenia, as well as in symptom production. Conclusions:Research to determine the role of the NMDA receptor in the pathophysiology of schizophrenia is warranted and now feasible. To be successful, this research will require the application of molecular biology techniques to postmortem brain tissue studies, in addition to traditional histochemical approaches.


2021 ◽  
Vol 13 ◽  
Author(s):  
Lei Yu ◽  
Zhiguang Huo ◽  
Jingyun Yang ◽  
Helena Palma-Gudiel ◽  
Patricia A. Boyle ◽  
...  

Glycosylation, the process of adding glycans (i.e., sugars) to proteins, is the most abundant post-translational modification. N-glycosylation is the most common form of glycosylation, and the N-glycan moieties play key roles in regulating protein functions and many other biological processes. Thus, identification and quantification of N-glycome (complete repertoire of all N-glycans in a sample) may provide new sources of biomarkers and shed light on health and disease. To date, little is known about the role of altered N-glycome in Alzheimer’s Disease and Alzheimer’s Disease-related Dementias (AD/ADRD). The current study included 45 older adults who had no cognitive impairment (NCI) at baseline, followed and examined annually, and underwent brain autopsy after death. During about 12-year follow-up, 15 developed mild cognitive impairment (MCI), 15 developed AD, and 15 remained NCI. Relative abundances of N-glycans in serum at 2 time points (baseline and proximate to death, ∼12.3 years apart) and postmortem brain tissue (dorsolateral prefrontal cortex) were quantified using MALDI-TOF-MS. Regression models were used to test the associations of N-glycans with AD/ADRD phenotypes. We detected 71 serum and 141 brain N-glycans, of which 46 were in common. Most serum N-glycans had mean fold changes less than one between baseline and proximate to death. The cross-tissue N-glycan correlations were weak. Baseline serum N-glycans were more strongly associated with AD/ADRD compared to change in serum N-glycans over time and brain N-glycans. The N-glycan associations were observed in both AD and non-AD neuropathologies. To our knowledge, this is the first comprehensive glycomic analysis in both blood and brain in relation to AD pathology. Our results suggest that altered N-glycans may serve as mechanistic biomarkers for early diagnosis and progression of AD/ADRD.


2019 ◽  
Vol 9 (9) ◽  
pp. 218
Author(s):  
Petr Zach ◽  
Jana Mrzílková ◽  
Jan Pala ◽  
Libor Uttl ◽  
Viera Kútna ◽  
...  

Background: CLARITY is a method of rendering postmortem brain tissue transparent using acrylamide-based hydrogels so that this tissue could be further used for immunohistochemistry, molecular biology, or gross anatomical studies. Published papers using the CLARITY method have included studies on human brains suffering from Alzheimer’s disease using mouse spinal cords as animal models for multiple sclerosis. Methods: We modified the original design of the Chung CLARITY system by altering the electrophoretic flow-through cell, the shape of the platinum electrophoresis electrodes and their positions, as well as the cooling and recirculation system, so that it provided a greater effect and can be used in any laboratory. Results: The adapted CLARITY system is assembled from basic laboratory components, in contrast to the original design. The modified CLARITY system was tested both on rat brain stained with a rabbit polyclonal anti-Iba-1 for microglial cells and on human nucleus accumbens stained with parvalbumin and tyrosine hydroxylase for visualization of specific neurons by confocal laser scanning microscopy. Conclusions: Our design has the advantage of simplicity, functional robustness, and minimal requirement for specialized additional items for the construction of the CLARITY apparatus.


2018 ◽  
Vol 10 (3) ◽  
pp. 141-149
Author(s):  
V. A. Golovacheva ◽  
K. A. Pozhidaev ◽  
A. A. Golovacheva

Cognitive impairment (CI) is common in patients with migraine; its causes and pathogenesis continue to be discussed. Some authors consider that migraine proper does not lead to decreased cognitive functions, neuroimaging changes in the brain white matter are asymptomatic in migraine; and CI in patients with this condition is caused by comorbidities (depression, anxiety disorder) and/or concurrent cerebrovascular and neurodegenerative diseases. Other authors report the pathogenetic role of migraine in the development of CI and the importance of the frequency of headache attacks and neuroimaging changes in the brain matter in migraine. The paper reviews clinical trials dealing with the prevalence, causes, and pathogenesis of CI in patients with migraine. It sets forth the current principles of prevention and treatment of CI in patients with this condition.


2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
C. Fourie ◽  
E. Kim ◽  
H. Waldvogel ◽  
J. M. Wong ◽  
A. McGregor ◽  
...  

NMDA and AMPA-type glutamate receptors and their bound membrane-associated guanylate kinases (MAGUKs) are critical for synapse development and plasticity. We hypothesised that these proteins may play a role in the changes in synapse function that occur in Huntington’s disease (HD) and Parkinson’s disease (PD). We performed immunohistochemical analysis of human postmortem brain tissue to examine changes in the expression of SAP97, PSD-95, GluA2 and GluN1 in human control, and HD- and PD-affected hippocampus and striatum. Significant increases in SAP97 and PSD-95 were observed in the HD and PD hippocampus, and PSD95 was downregulated in HD striatum. We observed a significant increase in GluN1 in the HD hippocampus and a decrease in GluA2 in HD and PD striatum. Parallel immunohistochemistry experiments in the YAC128 mouse model of HD showed no change in the expression levels of these synaptic proteins. Our human data show that major but different changes occur in glutamatergic proteins in HD versus PD human brains. Moreover, the changes in human HD brains differ from those occurring in the YAC128 HD mouse model, suggesting that unique changes occur at a subcellular level in the HD human hippocampus.


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