Elena Bellavista

Immunoproteasome and LMP2 polymorphism in aged and Alzheimer's disease brains.

In this study, we investigated the presence and role of immunoproteasome and its LMP2 subunit polymorphism at codon 60 in Alzheimers disease (AD). Immunoproteasome was present in brain areas such as hippocampus and cerebellum and localized in neurons, astrocytes and endothelial cells. A higher expression of immunoproteasome was found in brain of AD patients than in brain of non-demented elderly, being its expression in young brain negligible or absent. Furthermore, AD affected regions showed a partial decrease in proteasome trypsin-like activity. The study of LMP2 polymorphism (R/H) showed that it does not influence LMP2 expression (neither the mRNA nor mature protein) in brain tissue. However, control brain areas of AD patients carrying the RR genotype showed an increased proteasome activity in comparison with RH carriers. To test whether this effect of the genotype might be related to AD onset we performed a genetic study, which allowed us to exclude an association of LMP2 codon 60 polymorphism with AD onset, despite its influence on the proteasome activity in human brain.

Immune System, Cell Senescence, Aging and Longevity - Inflamm-Aging Reappraised

Inflamm-aging, that is the age-associated inflammatory status, is considered one of the most striking consequences of immunosenescence, as it is believed to be linked to the majority of age-associated diseases sharing an inflammatory basis. Nevertheless, evidence is emerging that inflamm-aging is at least in part independent from immunological stimuli. Moreover, centenarians who avoided or delayed major inflammatory diseases display markers of inflammation. In this paper we proposed a reappraisal of the concept of inflamm-aging, suggesting that its pathological effects can be independent from the total amount of pro-inflammatory mediators, but they would be rather associated with the anatomical district and type of cells where they are produced and where they primarily act.

Evidence for Sub-Haplogroup H5 of Mitochondrial DNA as a Risk Factor for Late Onset Alzheimer's Disease

Background Alzheimers Disease (AD) is the most common neurodegenerative disease and the leading cause of dementia among senile subjects. It has been proposed that AD can be caused by defects in mitochondrial oxidative phosphorylation. Given the fundamental contribution of the mitochondrial genome (mtDNA) for the respiratory chain, there have been a number of studies investigating the association between mtDNA inherited variants and multifactorial diseases, however no general consensus has been reached yet on the correlation between mtDNA haplogroups and AD. Methodology/Principal Findings We applied for the first time a high resolution analysis (sequencing of displacement loop and restriction analysis of specific markers in the coding region of mtDNA) to investigate the possible association between mtDNA-inherited sequence variation and AD in 936 AD patients and 776 cognitively assessed normal controls from central and northern Italy. Among over 40 mtDNA sub-haplogroups analysed, we found that sub-haplogroup H5 is a risk factor for AD (OR = 1.85, 95% CI:1.04–3.23) in particular for females (OR = 2.19, 95% CI:1.06–4.51) and independently from the APOE genotype. Multivariate logistic regression revealed an interaction between H5 and age. When the whole sample is considered, the H5a subgroup of molecules, harboring the 4336 transition in the tRNAGln gene, already associated to AD in early studies, was about threefold more represented in AD patients than in controls (2.0% vs 0.8%; p = 0.031), and it might account for the increased frequency of H5 in AD patients (4.2% vs 2.3%). The complete re-sequencing of the 56 mtDNAs belonging to H5 revealed that AD patients showed a trend towards a higher number (p = 0.052) of sporadic mutations in tRNA and rRNA genes when compared with controls. Conclusions Our results indicate that high resolution analysis of inherited mtDNA sequence variation can help in identifying both ancient polymorphisms defining sub-haplogroups and the accumulation of sporadic mutations associated with complex traits such as AD.

Immunoproteasomes and immunosenescence

Aging is a complex process which is accompanied with the decline and the reshaping of different functions of the body. In particular the immune system is characterized, during ageing (immunosenescence) by a remodeling of innate immunity (well preserved, up-regulated) and clonotypical immunity (severely altered) and by the occurrence of a chronic inflammatory process (inflammaging) which are, at least in part, genetically controlled. In this scenario, it can be anticipated that a crucial role is played by age-related structural and functional alterations and modifications of proteasomes and immunoproteasomes, the last being a key component of antigen processing and MHC class I antigen presentation. A variety of experimental data are available, suggesting that proteasomes are affected by age, and that in centenarians they are relatively preserved. On the contrary, few data are available on immunoproteasomes, likely as a consequence of the poverty of suitable cellular models. Lymphoblastoid cell lines from EBV immortalized B cells from old donors is envisaged as a possible model for the study of immunoproteasomes in humans and their changes with age. Thus, basic questions such as those related to possible consequences, for immune responses in infectious diseases and cancer, of age-related alterations of antigen processing and presenting, change with age of self-antigen repertoire, and the genetic basis of immunoproteasome activity and its change with age, remain largely unanswered.

Genes, ageing and longevity in humans: problems, advantages and perspectives.

Many epidemiological data indicate the presence of a strong familial component of longevity that is largely determined by genetics, and a number of possible associations between longevity and allelic variants of genes have been described. A breakthrough strategy to get insight into the genetics of longevity is the study of centenarians, the best example of successful ageing. We review the main results regarding nuclear genes as well as the mitochondrial genome, focusing on the investigations performed on Italian centenarians, compared to those from other countries. These studies produced interesting results on many putative “longevity genes”. Nevertheless, many discrepancies are reported, likely due to the population-specific interactions between gene pools and environment. New approaches, including large-scale studies using high-throughput techniques, are urgently needed to overcome the limits of traditional association studies performed on a limited number of polymorphisms in order to make substantial progress to disentangle the genetics of a trait as complex as human longevity.

Immunoproteasome LMP2 60HH variant alters MBP epitope generation and reduces the risk to develop multiple sclerosis in Italian female population

Background Albeit several studies pointed out the pivotal role that CD4+T cells have in Multiple Sclerosis, the CD8+ T cells involvement in the pathology is still in its early phases of investigation. Proteasome degradation is the key step in the production of MHC class I-restricted epitopes and therefore its activity could be an important element in the activation and regulation of autoreactive CD8+ T cells in Multiple Sclerosis. Methodology/Principal Findings Immunoproteasomes and PA28-αβ regulator are present in MS affected brain area and accumulated in plaques. They are expressed in cell types supposed to be involved in MS development such as neurons, endothelial cells, oligodendrocytes, macrophages/macroglia and lymphocytes. Furthermore, in a genetic study on 1262 Italian MS cases and 845 controls we observed that HLA-A*02+ female subjects carrying the immunoproteasome LMP2 codon 60HH variant have a reduced risk to develop MS. Accordingly, immunoproteasomes carrying the LMP2 60H allele produce in vitro a lower amount of the HLA-A*0201 restricted immunodominant epitope MBP111–119. Conclusion/Significance The immunoproteasome LMP2 60HH variant reduces the risk to develop MS amongst Italian HLA-A*02+ females. We propose that such an effect is mediated by the altered proteasome-dependent production of a specific MBP epitope presented on the MHC class I. Our observations thereby support the hypothesis of an involvement of immunoproteasome in the MS pathogenesis.

Inflammaging and cancer: a challenge for the Mediterranean diet.

Aging is considered the major risk factor for cancer, one of the most important mortality causes in the western world. Inflammaging, a state of chronic, low-level systemic inflammation, is a pervasive feature of human aging. Chronic inflammation increases cancer risk and affects all cancer stages, triggering the initial genetic mutation or epigenetic mechanism, promoting cancer initiation, progression and metastatic diffusion. Thus, inflammaging is a strong candidate to connect age and cancer. A corollary of this hypothesis is that interventions aiming to decrease inflammaging should protect against cancer, as well as most/all age-related diseases. Epidemiological data are concordant in suggesting that the Mediterranean Diet (MD) decreases the risk of a variety of cancers but the underpinning mechanism(s) is (are) still unclear. Here we review data indicating that the MD (as a whole diet or single bioactive nutrients typical of the MD) modulates multiple interconnected processes involved in carcinogenesis and inflammatory response such as free radical production, NF-κB activation and expression of inflammatory mediators, and the eicosanoids pathway. Particular attention is devoted to the capability of MD to affect the balance between pro- and anti-inflammaging as well as to emerging topics such as maintenance of gut microbiota (GM) homeostasis and epigenetic modulation of oncogenesis through specific microRNAs.

Charting the NF-κB pathway interactome map.

Inflammation is part of a complex physiological response to harmful stimuli and pathogenic stress. The five components of the Nuclear Factor κB (NF-κB) family are prominent mediators of inflammation, acting as key transcriptional regulators of hundreds of genes. Several signaling pathways activated by diverse stimuli converge on NF-κB activation, resulting in a regulatory system characterized by high complexity. It is increasingly recognized that the number of components that impinges upon phenotypic outcomes of signal transduction pathways may be higher than those taken into consideration from canonical pathway representations. Scope of the present analysis is to provide a wider, systemic picture of the NF-κB signaling system. Data from different sources such as literature, functional enrichment web resources, protein-protein interaction and pathway databases have been gathered, curated, integrated and analyzed in order to reconstruct a single, comprehensive picture of the proteins that interact with, and participate to the NF-κB activation system. Such a reconstruction shows that the NF-κB interactome is substantially different in quantity and quality of components with respect to canonical representations. The analysis highlights that several neglected but topologically central proteins may play a role in the activation of NF-κB mediated responses. Moreover the interactome structure fits with the characteristics of a bow tie architecture. This interactome is intended as an open network resource available for further development, refinement and analysis.

Effects of Donepezil,Galantamine and Rivastigmine in 938 Italian Patients with Alzheimer’s Disease

AbstractBackground: Acetylcholinesterase inhibitors (AChEIs) have been used to improve cognitive status and disability in patients with mild to moderate Alzheimer’s disease (AD). However, while the efficacy of AChEIs (i.e. how they act in randomized controlled trials) in this setting is widely accepted, their effectiveness (i.e. how they behave in the real world) remains controversial. Objective: To compare the effects of three AChEIs, donepezil (Aricept®), galantamine (Reminyl®) and rivastigmine (Exelon®), in an Italian national, prospective, observational study representative of the ‘real world’ clinical practice of AChEI treatment for AD. Methods: 938 patients with mild to moderate AD collected within the framework of the Italian National Cronos Project (CP), involving several UVAs (AD Evaluation Units) spread over the entire national territory, who were receiving donepezil, galantamine or rivastigmine were followed for 36 weeks by measuring: (i) function, as determined by the Activities of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL) scales; (ii) cognition, as measured by the Mini-Mental State Examination (MMSE) and the Alzheimer’s Disease Assessment Scale-cognitive subscale (ADAS-cog) [primary outcome measures]; and (iii) behaviour, as measured on the Neuropsychiatric Inventory (NPI) and Clinical Dementia Rating (CDR) scale. Moreover, all patients were genotyped for apolipoprotein E (apoE) genetic variants. Results: No statistically significant improvement in the primary outcome measures (MMSE and ADAS-Cog) was observed with drug therapy at 36 weeks, at which point all groups had lost, on average, 1 point on the MMSE and gained 2–3 points on the ADAS-Cog scale compared with baseline. On the secondary outcome measures at week 36, all treatment groups showed a significant worsening on the ADL and IADL scales compared with baseline, while on the NPI scale there were no significant differences from baseline except for the galantamine-treated group which worsened significantly. Moreover, patients receiving galantamine worsened significantly compared with the donepezil-treated group on the IADL scale. ApoE ε4 allele did not influence the effect of drug therapy. Conclusion: Over a 36-week follow-up period, no significant difference in the effects of donepezil, galantamine and rivastigmine on a variety of functional and cognitive parameters was observed in a large number of apoE-genotyped patients with mild to moderate AD recruited within the framework of a national project representative of the scenario usually encountered in actual clinical practice in Italy. The limitations (possibility of administration of lower drug doses than are used in clinical trials, relatively short follow-up period and the lack of randomization) and strengths (large number of patients, concomitant observation of the three drugs and the number of parameters assessed, including apoE genotype) of the present study are acknowledged. Our type of naturalistic study should complement clinical trials because ‘real world’ practice operates in the face of the numerous variables (e.g. health status and co-morbidities) associated with a complex disease such as AD in elderly people.

Studies on immunoproteasome in human liver. Part I: Absence in fetuses, presence in normal subjects, and increased levels in chronic active hepatitis and cirrhosis

Despite the central role of proteasomes in relevant physiological pathways and pathological processes, this topic is unexpectedly largely unexplored in human liver. Here we present data on the presence of proteasome and immunoproteasome in human livers from normal adults, fetuses and patients affected by major hepatic diseases such as cirrhosis and chronic active hepatitis. Immunohistochemistry for constitutive (alpha4 and beta1) and inducible (LMP2 and LMP7) proteasome subunits, and for the PA28alphabeta regulator, was performed in liver samples from 38 normal subjects, 6 fetuses, 2 pediatric cases, and 19 pathological cases (10 chronic active hepatitis and 9 cirrhosis). The immunohistochemical data have been validated and quantified by Western blotting analysis. The most striking result we found was the concomitant presence in hepatocyte cytoplasm of all healthy subjects, including the pediatric cases, of constitutive proteasome and immunoproteasome subunits, as well as PA28alphabeta. At variance, immunoproteasome was not present in hepatocytes from fetuses, while a strong cytoplasmic and nuclear positivity for LMP2 and LMP7 was found in pathological samples, directly correlated to the histopathological grade of inflammation. At variance from other organs such as the brain, immunoproteasome is present in livers from normal adult and pediatric cases, in apparent absence of pathological processes, suggesting the presence of a peculiar regulation of the proteasome/immunoproteasome system, likely related to the physiological stimuli derived from the gut microbiota after birth. Other inflammatory stimuli contribute in inducing high levels of immunoproteasome in pathological conditions, where its role deserve further attention.