Cristina Gussago

Epigenetic regulation of fatty acid amide hydrolase in Alzheimer disease.

Objective Alzheimer disease (AD) is a progressive, degenerative and irreversible neurological disorder with few therapies available. In search for new potential targets, increasing evidence suggests a role for the endocannabinoid system (ECS) in the regulation of neurodegenerative processes. Methods We have studied the gene expression status and the epigenetic regulation of ECS components in peripheral blood mononuclear cells (PBMCs) of subjects with late-onset AD (LOAD) and age-matched controls (CT). Results We found an increase in fatty acid amide hydrolase (faah) gene expression in LOAD subjects (2.30±0.48) when compared to CT (1.00±0.14; *p<0.05) and no changes in the mRNA levels of any other gene of ECS elements. Consistently, we also observed in LOAD subjects an increase in FAAH protein levels (CT: 0.75±0.04; LOAD: 1.11±0.15; *p<0.05) and activity (pmol/min per mg protein CT: 103.80±8.73; LOAD: 125.10±4.00; *p<0.05), as well as a reduction in DNA methylation at faah gene promoter (CT: 55.90±4.60%; LOAD: 41.20±4.90%; *p<0.05). Conclusions Present findings suggest the involvement of FAAH in the pathogenesis of AD, highlighting the importance of epigenetic mechanisms in enzyme regulation; they also point to FAAH as a new potential biomarker for AD in easily accessible peripheral cells.

Involvement of 5-Lipoxygenase in Alzheimer's Disease: A Role for DNA Methylation

Lipoxygenases play a major role in the neuropathology of Alzheimers disease (AD), even though the underlying mechanisms are as yet poorly understood. Here, we studied the epigenetic regulation of 5-lipoxygenase (5-LOX) in peripheral blood mononuclear cells of subjects with late-onset AD and age-matched controls. We found a significant increase in 5-LOX gene expression in AD subjects compared to healthy controls, paralleled by increased 5-LOX protein and leukotriene B4, the 5-LOX product. In addition, a consistent reduction in DNA methylation at 5-LOX gene promoter was documented in AD versus healthy subjects. Taken together, our findings further support a role for 5-LOX in vulnerability to neurodegeneration.

Different Adenosine A2A Receptor Expression in Peripheral Cells from Elderly Patients with Vascular Dementia and Alzheimer's Disease

The line between vascular dementia (VaD) and Alzheimers disease (AD) is often blurred. In this study we investigated whether adenosine A2A receptor (A2AR) expression can be used to differentiate between VaD and AD. We evaluated the expression of this receptor in the peripheral blood mononuclear cells of patients with VaD, mild cognitive impairment, AD, and controls. We found statistically significant lower levels of A2AR mRNA in VaD compared to AD subjects. These data suggest that A2AR expression may help in the differential diagnosis between VaD and AD.

GRN Thr272fs clinical heterogeneity: a case with atypical late onset presenting with a dementia with Lewy bodies phenotype.

We describe a case of late onset frontotemporal dementia carrying the g.1977_1980 delCACT (Thr272fs) mutation in progranulin (GRN) gene, characterized by a positive family history for dementia and a clinical phenotype resembling dementia with Lewy bodies. Symptoms included prominent visuospatial impairment, complex misidentification syndrome, visual zooptic hallucinations, hypersomnia, mental fluctuations, and signs of parkinsonism. The patient showed normal cerebrospinal fluid levels of amyloid-β, tau, and Ptau biomarkers, an asymmetric pattern of cerebral atrophy and hypoperfusion, and parietal hypometabolism. A major contributing factor to the diagnosis was the testing of plasmatic progranulin levels (extremely low), which prompted us to sequence GRN.

Gene promoter methylation and expression of Pin1 differ between patients with frontotemporal dementia and Alzheimer's disease

Frontotemporal Dementia (FTD) and Alzheimers Disease (AD) share the accumulation of fibrillar aggregates of misfolded proteins. To better understand these neurodegenerative diseases and identify biomarkers in easily accessible cells, we investigated DNA methylation at Pin1 gene promoter and its expression in peripheral blood mononuclear cells of FTD patients. We found a lower gene expression of Pin1 with a higher DNA methylation in three CpG sites at Pin1 gene promoter analysed in FTD subjects, in contrast to a higher gene expression with a lower methylation in AD subjects and controls. These data suggest an important and distinct involvement of Pin1 in these two types of dementia.

Protein signature in cerebrospinal fluid and serum of Alzheimer’s disease patients: The case of apolipoprotein A-1 proteoforms

In the diagnosis of Alzheimer’s disease (AD) total tau (T-tau), tau phosphorylated at threonine 181 (P-tau181), and the 42 amino acid isoform of alpha β-amyloid (Aβ) are well established surrogate CSF markers. However, there is a constant need for new diagnostic markers to identify the disease at a very early stage. The identification of new molecules for AD diagnosis and monitoring in CSF is hampered by several “confounding” factors including intra- and inter-individual, pre-analytical and analytical variabilities. In an attempt to partially overcome patient’s variability and to determine new molecules significantly dysregulated in CSF, we assessed the proteome profile of low molecular weight protein species in CSF and serum of the same patients. CSFs and sera from 36 ADs, 32 iNPHs (idiopathic normal pressure hydrocephalus) and 12 controls were compared by MALDI profiling (non-parametric statistics, CV<20%, AUC>0.750). After protein identification by mass spectrometry, the proteoform composition was assessed by 2-D DIGE/MS. Results indicated that CSF of iNPH can be used as control. Serum and CSF of AD patients shows a specific protein profile compared to iNPH samples. A variation (p<0.01) of Apo A-1 levels in AD, together with a specific dysregulation of Apo A-1 proteoforms was observed. The profiling of CSF and serum of the same patients, suggests that the decrement of total Apo A-1 occurs specifically in CSF. Serum and CSF of AD shows a characteristic Apo A-1 proteoform pattern suggesting it as potential marker which can support the clinical workflow adopted for AD diagnosis and progression.

Down-regulation of adenosine A1 and A2A receptors in peripheral cells from idiopathic normal-pressure hydrocephalus patients

Idiopathic normal-pressure hydrocephalus (iNPH) is a neurological disease that usually develops in the elderly. Natural history of iNPH is still unknown. It has been hypothesized that cerebrovascular diseases could have a role in etiology of chronic hydrocephalus and studies show an increased prevalence of cardiovascular diseases in iNPH patients. Moreover, evidences show a possible alteration of immune system in iNPH patients. Adenosine (Ado) is a metabolite produced in response to metabolic stress and injury. Adenosine and its receptors play an important role in vascular protection and in the modulation of inflammatory reactions and neuroinflammation. Our aim is to evaluate gene and protein expression of A1R and A2AR in the peripheral blood mononuclear cells (PBMCs) from iNPH patients compared to control subjects. We investigate if Ado system, that plays an important role in central nervous system, in vascular system, and also in inflammation, is involved in pathophysiology of iNPH disease. Our analysis showed that A1R mRNA levels and A1R density in PBMCs from iNPH patients were significantly lower than CT subjects (0.84 ± 0.12 and 2.42 ± 0.42, p<0.001 and 0.31 ± 0.02 and 0.42 ± 0.04, p=0.043; respectively). About A2AR, the gene expression in PBMCs was significantly lower in iNPH than CT (0.65 ± 0.09 and 1.5 ± 0.14, p<0.001) as well as there was a trend in protein expression: iNPH and CT (0.51 ± 0.05 and 0.62 ± 0.03; p=0.172). This preliminary study underlines the involvement of Ado system in iNPH disease whose pathophysiology is still unclear.

Phenotypic Variability associated with the C9ORF72 Hexanucleotide Repeat Expansion: A Sporadic Case of Frontotemporal Lobar Degeneration with Prodromal Hyposmia and Predominant Semantic Deficits

We describe a sporadic case of frontotemporal lobar degeneration, associated with the C9ORF72 mutation, with prominent behavioral changes and semantic deficits. Predominant deficits in naming, vocabulary, word comprehension, and face and object recognition emerged on neuropsychological assessment. Amnesia, behavioral changes, and isolated psychotic symptoms were also present. Hyposmia was an unspecific prodromal sign. Brain imaging showed basofrontal and temporopolar hypometabolism bilaterally, and predominantly left-sided atrophy. Levels of cerebrospinal fluid biomarkers (amyloid-β, tau and p-tau) were normal. This description further confirms the heterogeneous presentation of the C9ORF72 mutation.

Increased expression of TREM2 in peripheral cells from mild cognitive impairment patients who progress into Alzheimer's disease

Neuroinflammation plays a role in the aetiopathogenesis of Alzheimers disease (AD). Triggering receptor expressed on myeloid cells 2 (TREM2), a cell surface receptor of the immunoglobulin superfamily, seems to have protective anti‐inflammatory activity in AD.

Adenosine Type A2A Receptor in Peripheral Cell from Patients with Alzheimer's Disease, Vascular Dementia, and Idiopathic Normal Pressure Hydrocephalus: A New/Old Potential Target.

As the European population gets older, the incidence of neurological disorders increases with significant impact on social costs. Despite differences in disease etiology, several brain disorders in the elderly (e.g., Alzheimers disease, vascular dementia, normal pressure hydrocephalus) share dementia as a common clinical feature. The current treatment for the majority of these diseases is merely symptomatic and does not modify the course of the illness. Symptoms of normal pressure hydrocephalus are the only ones that can be modified if they are recognized in time and treated appropriately. Therefore, an important clinical strategy may be disclosed by pathogenic pathways that can be modified and to find drugs that can slow down or even arrest disease progression. Possibly a way to answer this question could be by re-examining all the molecules which have so far succeeded in improving many aspects of cognitive deterioration in some neurodegenerative conditions, that were not considered because of controversial opinions. The main purpose of this summary is to further substantiate the hypothesis that the pathway of adenosine type A2A receptor could be used as a potential target to develop new/old therapeutic strategies.