Angela Maselli

Estrogen receptor profiles in human peripheral blood lymphocytes

Estrogens are well-known regulators of the immune responses. Most of their effects are mediated by two receptors: estrogen receptor (ER)alpha and ERbeta. Up to date the presence of intracellular ER in human immune cells represents a controversial issue, while their surface membrane expression has scarcely been explored. In this study we investigated the intracellular and cell surface expression of ERalpha and ERbeta in human peripheral blood lymphocytes (PBL) by flow and static cytometry as well as by Western Blot. To this aim we used five different commercial antibodies recognizing distinct ER epitopes. We observed that CD4(+) and CD8(+) T lymphocytes, B lymphocytes and NK cells contain intracellular ERalpha and ERbeta, being the ERalpha46 isoform the most represented ER. However, significant differences could be observed among the antibodies studied in terms of immunoreactivity and specificity. Importantly, we also found a cell surface expression of ERalpha46 isoform. We also observed that a membrane-impermeant form of E2 induced a rapid phosphorylation of extracellular signal-regulated kinase (ERK), a significant proliferation of T lymphocytes, and IFN-gamma production by NK cells, thus suggesting the expression of a functional mERalpha. In conclusion our data could provide new insights as concerns the estrogen-related mechanisms of immune system modulation. They also suggest the need for a reappraisal of the experimental conditions for the characterization of the ER expression.

Role of autophagy in immunity and autoimmunity, with a special focus on systemic lupus erythematosus

Autophagy is a lysosome‐mediated catabolic process that allows cells to degrade unwanted cytoplasmic constituents and to recycle nutrients. Autophagy is also involved in innate and adaptive immune responses, playing a key role in interactions against microbes, in antigen processing for major histocompatibility complex (MHC) presentation, and in lymphocyte development, survival, and proliferation. Over recent years, perturbations in autophagy have been implicated in a number of diseases, including autoimmunity. Systemic lupus erythematosus (SLE) is a multifactorial disease characterized by autoimmune responses against self‐antigens generated by dying cells. Genome‐wide association studies have linked several single‐nucleotide polymorphisms (SNPs) in the autophagy‐related gene Atg5 to SLE susceptibility. Loss of Atg5‐dependent effects, including clearance of dying cells and cell antigen presentation, might contribute to the autoimmunity and inflammation associated with SLE. Moreover, activation of the mammalian target of rapamycin (mTOR), a key player in the autophagy regulation, has recently been demonstrated in SLE, confirming an altered autophagy pathway in this disease. In the present review, we summarize the autophagy mechanisms, their molecular regulation, and their relevance in immunity and autoimmunity. The potential of targeting autophagy pathway in SLE, by developing innovative therapeutic approaches, has finally been discussed.—Pierdominici, M., Vomero, M., Barbati, C., Colasanti, T., Maselli, A., Vacirca, D., Giovannetti, A., Malorni, W., Ortona, E. Role of autophagy in immunity and autoimmunity, with a special focus on systemic lupus erythematosus. FASEB J. 26, 1400‐1412 (2012). www.fasebj.org

T lymphocytes from patients with systemic lupus erythematosus are resistant to induction of autophagy

Autophagy, the cytoprotection mechanism that takes place under metabolic impairment, has been implicated in the pathogenesis of autoimmunity. Here, we investigated the spontaneous and induced autophagic behavior of T lymphocytes from patients with systemic lupus erythematosus (SLE) compared with that of T lymphocytes from healthy donors by measuring the autophagy marker microtubule‐associated protein 1 light chain 3 (LC3)‐II. No significant differences in spontaneous autophagy were found between T lymphocytes from patients with SLE and from healthy donors, apart from CD4+ naive T cells from patients with SLE in which constitutively higher levels of autophagy (P < 0.001) were detected. At variance, whereas treatment of T lymphocytes from healthy donors with serum IgG from patients with SLE resulted in a 2‐fold increase in LC3‐II levels (P<0.001), T lymphocytes from SLE patients were resistant to autophagic induction and also displayed an up‐regulation of genes negatively regulating autophagy, e.g., α‐synuclein. These findings could open new perspectives in the search for pathogenetic determinants of SLE progression and in the development of therapeutic strategies aimed to recover T‐cell compartment homeostasis by restoring autophagic susceptibility.—Alessandri, C., Barbati, C., Vacirca, D., Piscopo, P., Confaloni, A., Sanchez, M., Maselli, A., Colasanti, T., Conti, F., Truglia, S., Perl, A., Valesini, G., Malorni, W., Ortona, E., Pierdominici, M. T lymphocytes from patients with systemic lupus erythematosus are resistant to induction of autophagy. FASEB J. 26, 4722–4732 (2012). www.fasebj.org

Sex-based differences in autoimmune diseases

Autoimmune diseases are characterized by an exaggerated immune response leading to damage and dysfunction of specific or multiple organs and tissues. Most autoimmune diseases are more prevalent in women than in men. Symptom severity, disease course, response to therapy and overall survival may also differ between males and females with autoimmune diseases. Sex hormones have a crucial role in this sex bias, with estrogens being potent stimulators of autoimmunity and androgens playing a protective role. Accumulating evidence indicates that genetic, epigenetic and environmental factors may also contribute to sex-related differences in risk and clinical course of autoimmune diseases. In this review, we discuss possible mechanisms for sex specific differences in autoimmunity with a special focus on three paradigmatic diseases: systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis.

Analyses of T cell phenotype and function reveal an altered T cell homeostasis in systemic sclerosis Correlations with disease severity and phenotypes

We investigated in systemic sclerosis (SSc) patients the T cell homeostasis and its relationship with the clinical course of the disease. Distribution of peripheral T cell subsets, thymic output, lymphocyte proliferation and apoptosis were analyzed by flow cytometry or ELISA. Age inappropriate levels of naive CD4(+) T cells and thymic output were observed. Proliferation of CD4(+) T cells, lymphocyte apoptosis and CD4(+) regulatory T (Treg) cell frequency were significantly higher than those observed in controls and significantly correlated with clinical phenotypes and clinical progression parameters i.e., diffusing capacity of the lung for carbon monoxide (DLCO) and disease activity. These data indicate that the evaluation of the T cell homeostasis can represent a valuable prognostic tool for SSc patients and it is useful to distinguish between limited and diffuse phenotypes. A therapeutic intervention targeted at reversing T cell homeostasis abnormalities would therefore potentially be helpful in counteracting disease progression.

Cell sex: a new look at cell fate studies

Cell death processes have been widely investigated in recent years in order to elucidate the different pathways involved in the complex machinery implicated in determining cell fate. Different forms of cell death have been described: Apart from the classical form of death known as necrosis, a well‐characterized traumatic injury of the cell, several additional forms of cell death have been identified. Of these, apoptosis has been characterized in the greatest detail. Defects in the mechanisms of cell demise (that is, an excess of or decrease in apoptosis) have been associated with the pathogenesis of a number of human diseases. Here we review some new aspects derived from recent insights into this field, particularly the hypothesis that cells of males and females could display several different features, including those determining their fate.—Maselli, A., Matarrese, P., Straface, E., Canu, S., Franconi, F., Malorni, W. Cell sex: a new look at cell fate studies. FASEB J. 23, 978–984 (2009)

Role of alpha-synuclein in autophagy modulation of primary human T lymphocytes

It has been demonstrated that α-synuclein can aggregate and contribute to the pathogenesis of some neurodegenerative diseases and it is capable of hindering autophagy in neuronal cells. Here, we investigated the implication of α-synuclein in the autophagy process in primary human T lymphocytes. We provide evidence that: (i) knocking down of the α-synuclein gene resulted in increased autophagy, (ii) autophagy induction by energy deprivation was associated with a significant decrease of α-synuclein levels, (iii) autophagy inhibition by 3-methyladenine or by ATG5 knocking down led to a significant increase of α-synuclein levels, and (iv) autophagy impairment, constitutive in T lymphocytes from patients with systemic lupus erythematosus, was associated with abnormal accumulation of α-synuclein aggregates. These results suggest that α-synuclein could be considered as an autophagy-related marker of peripheral blood lymphocytes, potentially suitable for use in the clinical practice.

Pyrimethamine Induces Apoptosis of Melanoma Cells via a Caspase and Cathepsin Double-Edged Mechanism

The unresponsiveness of metastatic melanoma to conventional chemotherapeutic and biological agents is largely due to the development of resistance to apoptosis. Pyrimethamine belongs to the group of antifolate drugs, and in addition to antiprotozoan effects, it exerts a strong proapoptotic activity, which we recently characterized in human T lymphocytes. However, no data regarding pyrimethamine anticancer activity are available thus far. To this end, we examined the in vitro effects of pyrimethamine on apoptosis, cell cycle distribution, and cell proliferation of human metastatic melanoma cell lines. The in vivo antitumor potential of pyrimethamine was evaluated in a severe combined immunodeficiency (SCID) mouse xenotransplantation model. Our data indicate that pyrimethamine, when used at a clinically relevant concentration, induced apoptosis in metastatic melanoma cells via the activation of the cathepsin B and the caspase cascade (i.e., caspase-8 and caspase-9) and subsequent mitochondrial depolarization. This occurred independently from CD95/Fas engagement. Moreover, pyrimethamine induced a marked inhibition of cell growth and an S-phase cell cycle arrest. Results obtained in SCID mice, injected s.c. with metastatic melanoma cells and treated with pyrimethamine, indicated a significant inhibitory effect on tumor growth. In conclusion, our results suggest that pyrimethamine-induced apoptosis may be considered as a multifaceted process, in which different inducers or regulators of apoptosis are simultaneously implicated, thus permitting death defects of melanoma cells to be bypassed or overcome. On these bases, we hypothesize that pyrimethamine could represent an interesting candidate for the treatment of metastatic melanoma.

Low expression of estrogen receptor β in T lymphocytes and high serum levels of anti-estrogen receptor α antibodies impact disease activity in female patients with systemic lupus erythematosus

BackgroundCurrent evidence indicates that estrogens, in particular 17β-estradiol (E2), play a crucial role in the gender bias of autoimmune diseases although the underlying molecular mechanisms have not yet been fully elucidated. Immune cells have estrogen receptors (ERs), i.e., ERα and ERβ, that play pro- and anti-inflammatory functions, respectively, and the presence of one estrogen receptor (ER) subtype over the other might change estrogen effects, promoting or dampening inflammation. In this study, we contributed to define the influences of E2 on T cells from female patients with systemic lupus erythematosus (SLE), a representative autoimmune disease characterized by a higher prevalence in women than in men (female/male ratio 9:1). Particularly, our aim was to evaluate whether alterations of ERα and ERβ expression in T cells from female SLE patients may impact lymphocyte sensitivity to E2 and anti-ERα antibody (anti-ERα Ab) stimulation interfering with cell signaling and display a direct clinical effect.MethodsSixty-one premenopausal female patients with SLE and 40 age-matched healthy donors were recruited. Patients were divided into two groups based on the SLE Disease Activity Index 2000 (SLEDAI-2K) (i.e., <6 and ≥6). ER expression was evaluated in T lymphocytes by flow cytometry, immunofluorescence, and Western blot analyses. Serum anti-ERα Ab levels were analyzed by enzyme-linked immunosorbent assay (ELISA). ER-dependent signaling pathways were measured by a phosphoprotein detection kit.ResultsIntracellular ERβ expression was significantly lower in T cells from patients with SLEDAI-2K ≥6 as compared with healthy donors and patients with SLEDAI-2K <6 and negatively correlated with disease activity. The expression of intracellular and membrane-associated-ERα was similar in SLE and control T cells. ER-dependent signaling pathways were activated in T cells from SLE patients with SLEDAI-2K ≥6, but not with SLEDAI-2K <6, when both membrane and intracellular ERs were stimulated by co-treatment with E2 and anti-ERα Abs.ConclusionsOur results demonstrate an altered ER profile in SLE patients, possibly contributing to SLE pathogenesis and interfering with clinical activity, and highlight the potential exploitation of T cell-associated ERβ as a biomarker of disease activity.

Autoantibodies to estrogen receptor α in systemic sclerosis (SSc) as pathogenetic determinants and markers of progression.

Systemic sclerosis (SSc) is a multisystem autoimmune disease of unknown etiology characterized by inflammation, autoantibody production, and fibrosis. It predominantly affects women, this suggesting that female sex hormones such as estrogens may play a role in disease pathogenesis. However, up to date, the role of estrogens in SSc has been scarcely explored. The activity of estrogens is mediated either by transcription activity of the intracellular estrogen receptors (ER), ERα and ERβ, or by membrane-associated ER. Since the presence of autoantibodies to ERα and their role as estrogen agonists interfering with T lymphocyte homeostasis were demonstrated in other autoimmune diseases, we wanted to ascertain whether anti-ERα antibodies were detectable in sera from patients with SSc. We detected anti-ERα antibody serum immunoreactivity in 42% of patients with SSc (30 out of 71 analyzed). Importantly, a significant association was found between anti-ERα antibody values and key clinical parameters of disease activity and severity. Fittingly, anti-ERα antibody levels were also significantly associated with alterations of immunological features of SSc patients, including increased T cell apoptotic susceptibility and changes in T regulatory cells (Treg) homeostasis. In particular, the percentage of activated Treg (CD4+CD45RA− FoxP3brightCD25bright) was significantly higher in anti-ERα antibody positive patients than in anti-ERα antibody negative patients. Taken together our data clearly indicate that anti-ERα antibodies, probably via the involvement of membrane-associated ER, can represent: i) promising markers for SSc progression but, also, ii) functional modulators of the SSc patients’ immune system.