B CELL CHANGES IN AGING

The aging of the immune system is a gradual and dynamic process that modifies some immunological functions. These changes are known as “immunosenescence” that have a great impact on immune performance in late life, contributing to the decreased ability of the elderly people to respond to emerging pathogens and to the decreased responsiveness to vaccinations. It is known that the adaptive immune functions are affected in the aged. In particular, with aging, the acquired compartment of the immune system shows significant modifications in both T and B cell branches. Thus, the adaptive immune response of elderly people is qualitatively and quantitatively reduced when compared to that observed in young people. Lifelong and chronic antigenic load are the major driving forces of this process that is associated with a general increase in the production of pro-inflammatory cytokines and other inflammatory molecules that render elderly people prone to frailty and susceptible to major age-related diseases, such as Alzheimer’s disease (AD). On the other hand, centenarians represent an example of successful aging because they have delayed diseases that normally cause mortality in the general population. The aim of this thesis is to study changes in immune system with age, also focusing on people genetically advantaged for healthy ageing (Centenarian Offspring) or unsuccessfully aged patients (Alzheimer’s Disease), paying attention principally on the naïve/memory B cell compartments. The presented data suggest that the study of naïve/memory B and T cell compartments may be relevant in the evaluation of biological ageing of the immune system

Functionalization of a layered oxide with organic moieties: towards hybrid proton conductors

The design of innovative proton conductors for intermediate-temperature fuel cells, closing the gap between PEMFC and SOFC, is a forefront research theme in materials chemistry. [1] Layered perovskites with the Dion-Jacobson structure (ALaNb2O7) have bidimensional lanthanum niobate sheets, separated by a layer of A+ cations. These can be substituted by a variety of molecules with soft chemistry, to yield inorganic-organic hybrids. In particular, the intercalation of amines, alcohols, carboxylic or phosphonic acids, and their covalent binding to the sheets has been demonstrated recently. [2-4]We present preliminary results on the intercalation and covalent bonding of different organic molecules, in order to develop hybrid proton conductors for use in intermediate temperature fuel cells. Smaller molecules (such as alcohols) are intercalated to expand the interlayer space, to form intermediates for the further binding of proton carriers such as imidazoles or sulfonates.The intercalation process is investigated by XRD (to measure the interlayer distance) and TGA (to determine the weight loss upon thermal decomposition). NMR is applied to confirm the covalent bonding between the organic and oxide parts. The intercalation behavior of different functional groups is explained in terms of van der Waals and/or hydrogen bonding between organic chains. The interplay of theory (ab initio and periodic DFT) and experiment allowed us to elucidate the 1H and 13C-NMR spectra, and to investigate the nature of interaction (i.e. ionic or covalent bond) of the organic chains with the interlayer surface

Trafficking phenotype and production of granzyme B by double negative B cells (IgG(+)IgD(-)CD27(-)) in the elderly.

The impairment of humoral immune response in elderly humans has been extensively demonstrated. We have reported the increase of memory B cells (IgG+IgD−CD27−, double negative, DN) population in the elderly, in which there is also a typical inflammatory micro-environment. In order to evaluate whether this pro-inflammatory status could influence the trafficking phenotype of naïve/memory B cells, we have assessed the expression of CCR7, CCR6, CXCR3, CXCR4, CXCR5 and CD62L on naïve/memory B cell subpopulations in young and elderly subjects. Moreover, the combination of pro-inflammatory interleukin-21 (IL-21) and B cell receptor (BCR) stimulation enables B cells to produce and secrete granzyme B (GrB), which plays a critical role in early anti-viral immune responses, in the regulation of autoimmune mechanisms and in cancer immunosurveillance. Our data demonstrate that in the elderly, naïve/memory B cell populations present a different expression of the studied receptors that could be discussed in terms of “inflamm-aging”. In particular IgG+IgD−CD27− DN B cells show a tissue trafficking phenotype and they can be stimulated to produce GrB

Immunosenescence, inflammation and Alzheimer’s disease

Ageing impacts negatively on the development of the immune system and its ability to fight pathogens. Progressive changes in the T-cell and B-cell systems over the lifespan of individuals have a major impact on the capacity to respond to immune challenges. The cumulative age-associated changes in immune competence are termed immunosenescence that is characterized by changes where adaptive immunity deteriorates, while innate immunity is largely conserved or even upregulated with age. On the other hand, ageing is also characterized by “inflamm-ageing”, a term coined to explain the inflammation commonly present in many age-associated diseases. It is believed that immune inflammatory processes are relevant in Alzheimer’s disease, the most common cause of dementia in older people. In the present paper we review data focusing on changes of some immunoinflammatory parameters observed in patients affected by Alzheimer’s diseas

A novel B cell population revealed by a CD38/CD24 gating strategy: CD38(-)CD24 (-) B cells in centenarian offspring and elderly people

The B cell arm of adaptive immunity undergoes significant modifications with age. Elderly people are characterized by impaired B cell responses reflected in a reduced ability to effectively respond against viruses and bacteria. Alterations of immunity with advancing age (immunosenescence) have been widely studied in centenarians who are considered a good example of successful aging. In recent years, attention has shifted to centenarian offspring (CO) as a model of people genetically advantaged for healthy aging and longevity. Here, we describe the preliminary characterization of a proposed new population of memory B cells, defined as CD19(+)CD38(-)CD24(-), which we find at higher frequencies in the elderly but less so in CO than healthy age-matched random controls. In addition, we found a decreased expression of RP105 (CD180), a toll-like receptor-associated molecule, on these cells. CD180 downregulation may potentially be a marker of immunosenescence. Moreover, we show that these CD19(+)CD38(-)CD24(-) B cells produce TNF and hypothesize that their observed expansion in the elderly might contribute to the increased inflammatory status sometimes designated "inflamm-aging

Centenarian Offspring: A Model for Understanding Longevity

Abstract: A main objective of current medical research is to improve the life quality of elderly people as priority of the continuous increase of ageing population. This phenomenon implies several medical, economic and social problems because of dramatic increase in number of non autonomous individuals affected by various pathologies. Accordingly, the research interest is focused on understanding the biological mechanisms involved in determining the positive ageing phenotype, i.e. the centenarian phenotype. In achieving this goal the choice of an appropriate study models is fundamental. Centenarians have been used as an optimal model for successful ageing. However, this model shows several limitations, i.e. the selection of appropriate controls and the use itself of the centenarians as a suitable model for healthy ageing. Thus, the interest has been centered on centenarian offspring, healthy elderly people. They may represent a model for understanding exceptional longevity for the following reasons: they exhibit a protective genetic background, cardiovascular and immunological profile, as well as a reduced rate of cognitive decline than age-matched people without centenarian relatives. Several of these aspects are summarized in this review based on the literature and the results of our studies

Expression of calpain-calpastatin system (CCS) member proteins in human lymphocytes of young and elderly individuals; pilot baseline data for the CALPACENT project.

Ubiquitous system of regulatory, calcium-dependent, cytoplasmic proteases – calpains – and their endogenous inhibitor – calpastatin – is implicated in the proteolytic regulation of activation, proliferation, and apoptosis of many cell types. However, it has not been thoroughly studied in resting and activated human lymphocytes yet, especially in relation to the subjects’ ageing process. The CALPACENT project is an international (Polish-Italian) project aiming at verifying the hypothesis of the role of calpains in the function of peripheral blood immune cells of Polish (Pomeranian) and Italian (Sicilian) centenarians, apparently relatively preserved in comparison to the general elderly population. In this preliminary report we aimed at establishing and comparing the baseline levels of expression of μ- and m-calpain and calpastatin in various, phenotypically defined, populations of human peripheral blood lymphocytes for healthy elderly Sicilians and Poles, as compared to these values observed in young cohort

Interactions between N-linked glycosylation and polymerisation of neuroserpin within the endoplasmic reticulum.

The neuronal serpin neuroserpin undergoes polymerisation as a consequence of point mutations that alter its conformational stability, leading to a neurodegenerative dementia called familial encephalopathy with neuroserpin inclusion bodies (FENIB). Neuroserpin is a glycoprotein with predicted glycosylation sites at asparagines 157, 321 and 401. We used site-directed mutagenesis, transient transfection, western blot, metabolic labelling and ELISA to probe the relationship between glycosylation, folding, polymerisation and degradation of neuroserpin in validated cell models of health and disease. Our data show that glycosylation at N157 and N321 plays an important role in maintaining the monomeric state of neuroserpin, and we propose this is the result of steric hindrance or effects on local conformational dynamics that can contribute to polymerisation. Asparagine residue 401 is not glycosylated in wild type neuroserpin and in several polymerogenic variants that cause FENIB, but partial glycosylation was observed in the G392E mutant of neuroserpin that causes severe, early-onset dementia. Our findings indicate that N401 glycosylation reports lability of the C-terminal end of neuroserpin in its native state. This C-terminal lability is not required for neuroserpin polymerisation in the endoplasmic reticulum, but the additional glycan facilitates degradation of the mutant protein during proteasomal impairment. In summary, our results indicate how normal and variant-specific N-linked glycosylation events relate to intracellular folding, misfolding, degradation and polymerisation of neuroserpin

Genetics of longevity. Data from the studies on Sicilian centenarians

The demographic and social changes of the past decades have determined improvements in public health and longevity. So, the number of centenarians is increasing as a worldwide phenomenon. Scientists have focused their attention on centenarians as optimal model to address the biological mechanisms of “successful and unsuccessful ageing”. They are equipped to reach the extreme limits of human life span and, most importantly, to show relatively good health, being able to perform their routine daily life and to escape fatal age-related diseases, such as cardiovascular diseases and cancer. Thus, particular attention has been centered on their genetic background and immune system. In this review, we report our data gathered for over 10 years in Sicilian centenarians. Based on results obtained, we suggest longevity as the result of an optimal performance of immune system and an overexpression of anti-inflammatory sequence variants of immune/inflammatory genes. However, as well known, genetic, epigenetic, stochastic and environmental factors seem to have a crucial role in ageing and longevity. Epigenetics is associated with ageing, as demonstrated in many studies. In particular, ageing is associated with a global loss of methylation state. Thus, the aim of future studies will be to analyze the weight of epigenetic changes in ageing and longevity

A new method for the determination of very small Γγ partial widths

We present a new method for the measurement of very small Γγ partial width that is important for the synthesis of elements in astrophysics. The method is based on the simultaneous detection of scattered beam, residual nucleus and decay γ rays. This method is optimized for the use of the CHIMERA detector at LNS. Experimental details are described