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

Anna Mikosik,Aleksandra Jasiulewicz,Adriana Martorana,Giuseppina Colonna-Romano,Calogero Caruso,Jacek M Witkowski,Matteo Bulati,Joanna Frąckowiak,Ewa Bryl,Jerzy Foerster,Silvio Buffa

doi:10.1186/1742-4933-10-27

Anna Mikosik, Aleksandra Jasiulewicz + Show 9 more

Open Access

https://doi.org/10.1186/1742-4933-10-27

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Abstract

BackgroundUbiquitous 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.ResultsWe have found significant differences in the expression of both μ- and m-calpain as well as calpastatin between various populations of peripheral blood lymphocytes (CD4+, CD8+ and CD19+), both between the age groups compared and within them. Interestingly, significantly higher amounts of μ- and m-calpains but not of calpastatin could be demonstrated in the CD4+CD28- and CD8+CD28- lymphocytes of old subjects (but not in the cells of young individuals), as compared to their CD28+ counterparts. Finally, decreased expression of both calpains in the elderly T cells is not related to the accumulation of effector/memory (CD45RO+) cells in the latter, as the expression of both calpains does not differ significantly between the naïve and memory T cells, while is significantly lower for elderly lymphocytes if both populations are taken separately.ConclusionsObserved differences in the amounts of CCS member proteins between various populations of lymphocytes of young and elderly subjects may participate in the impaired proliferative activity of these cells in the elderly.

Highlights

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
Significant differences in the amount of both μ- and m-calpain could be seen between the CD4+ and CD8+ lymphocytes of both young and old individuals, with the respective amount being significantly higher for the CD8+ cells (Figure 1 A, B)
Significantly lower expression of both calpains in the CD4+ and CD8+ cells of elderly subjects shown in the Figure 1 is preserved in both subpopulations of these cells differing in CD28 expression; regardless of being CD28+ or CD28, the lymphocytes of both lineages of the elderly express significantly less μ- and m-calpain than those derived from young individuals (Figure 2A, B, D, E)

Summary

Introduction

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. Calpain family consists of a classic pair of the enzymes (μ-calpain and m-calpain-see below) that do not exhibit tissue specificity and are referred to as the ‘typical’ and ‘ubiquitous,’ and a larger group of tissue - specific calpains, occurring only in certain organs Their respective names - μ-calpain (calpain I) and m-calpain (calpain II) reflect the respective in vitro Ca2+ concentrations required for full proteolytic activity; μ-calpain respectively requires 1–100 μM Ca2+ and m-calpain 0.1 - 1 mM Ca2+ [3]. The two ubiquitous calpains and calpastatin, remaining in a precarious balance within cytoplasm, form the CCS system

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