Changes in T cell phenotype and activated MAPKs are correlated to impaired cellular responses to antigens and glucocorticoids during HTLV-I infection

Latency Reversing Agents: Kick and Kill of HTLV-1?

Human T-cell leukemia virus type 1 (HTLV-1), the cause of adult T-cell leukemia/lymphoma (ATLL), is a retrovirus, which integrates into the host genome and persistently infects CD4⁺ T-cells. Virus propagation is stimulated by (1) clonal expansion of infected cells and (2) de novo infection. Viral gene expression is induced by the transactivator protein Tax, which recruits host factors like positive transcription elongation factor b (P-TEFb) to the viral promoter. Since HTLV-1 gene expression is repressed in vivo by viral, cellular, and epigenetic mechanisms in late phases of infection, HTLV-1 avoids an efficient CD8⁺ cytotoxic T-cell (CTL) response directed against the immunodominant viral Tax antigen. Hence, therapeutic strategies using latency reversing agents (LRAs) sought to transiently activate viral gene expression and antigen presentation of Tax to enhance CTL responses towards HTLV-1, and thus, to expose the latent HTLV-1 reservoir to immune destruction. Here, we review strategies that aimed at enhancing Tax expression and Tax-specific CTL responses to interfere with HTLV-1 latency. Further, we provide an overview of LRAs including (1) histone deacetylase inhibitors (HDACi) and (2) activators of P-TEFb, that have mainly been studied in context of human immunodeficiency virus (HIV), but which may also be powerful in the context of HTLV-1.

Accelerated immunosenescence in rheumatoid arthritis: impact on clinical progression

Patients with rheumatoid arthritis (RA) develop features of accelerated ageing, including immunosenescence. These changes include decreased thymic functionality, expansion of late-differentiated effector T cells, increased telomeric attrition, and excessive production of cytokines (senescence-associated secretory phenotype). The progression of RA has been associated with the early development of age-related co-morbidities, including osteoporosis, cardiovascular complications, and cognitive impairment. Here I review data supporting the hypothesis that immune-senescence contributes to the aggravation of both articular and extra-articular manifestations. Of note, poor cognitive functions in RA were associated with senescent CD28- T cells, inflammaging, and autoantibodies against brain antigens. The pathways of immune-to-brain communication are discussed and provide the rationale for the cognitive impairment reported in RA.

Expression patterns of mesenchymal stem cell-specific proteins in adipose tissue-derived cells: possible immunosuppressing agent in partial allograft for restoring the urinary bladder in rabbits

ABSTRACT: Adipose tissue-derived stem cells (ADSCs) are an attractive source of mesenchymal stem cells (MSCs) for use in tissue engineering and clinical applications. This paper focuses on the characterization of ADSCs used as immunosuppressive agent in rabbits undergoing partial allograft for urine bladder restorage. For this study highlighted the characterization of the ADSCs used as immunosuppressive agents in rabbits submitted to partial allograft for restoration of the urinary vesicle, using 25 animals, six months old, New Zealand. ADSCs at the third peal were characterized by the MSC-specific CD105, CD73 and CD90 expression and by the absence of the hematopoietic marker CD45, as revealed by flow cytometry analysis. Moreover, ADSCs were efficient in preventing allograft rejection from the urinary bladder, as judged by biochemical, clinical and ultrasonography analysis. Together, these results compose characterization of protein expression profiles and immunosuppressive functionality of ADSCs in rabbits, which had undergone partial allografts of the urinary bladder, foreseeing future applications in clinical practice.

Caffeine and high intensity exercise: Impact on purinergic and cholinergic signalling in lymphocytes and on cytokine levels

This study evaluated the effects of caffeine in combination with high-intensity interval training (HIIT) on sensitivity to glucocorticoids and proliferation of lymphocytes, IL-6 and IL-10 levels and NTPDase, adenosine deaminase (ADA) and acetylcholinesterase (AChE) activity in rat lymphocytes. The animals were divided into groups: control, caffeine 4 mg/kg, caffeine 8 mg/kg, HIIT, HIIT plus caffeine 4 mg/kg and HIIT plus caffeine 8 mg/kg. The rats were trained three times a week for 6 weeks for a total workload 23% of body weight at the end of the experiment. Caffeine was administered orally 30 min before the training session. When lymphocytes were stimulated with phytohaemagglutinin no changes were observed in proliferative response between trained and sedentary animals; however, when caffeine was associated with HIIT an increase in T lymphocyte proliferation and in the sensitivity of lymphocytes to glucocorticoids occurred. ATP and ADP hydrolysis was decreased in the lymphocytes of the animals only trained and caffeine treatment prevented alterations in ATP hydrolysis. HIIT caused an increase in the ADA and AChE activity in lymphocytes and this effect was more pronounced in rats trained and supplemented with caffeine. The level of IL-6 was increased while the level of IL-10 was decreased in trained animals (HIIT) and caffeine was capable of preventing this exercise effect. Our findings suggest that caffeine ingestion attenuates, as least in part, the immune and inflammatory alterations following a prolonged HIIT protocol.

Immunosenescence is associated with human cytomegalovirus and shortened telomeres in type I bipolar disorder

OBJECTIVE

Bipolar disorder (BD) has been associated with persistent low-grade inflammation and premature cell senescence, as shown by reduced telomere length (TL). The human cytomegalovirus (CMV) has increasingly been implicated in accelerated immunosenescence in aging studies. Here, we compared CMV serology and its relationships with cell senescence markers, including TL and lymphocyte subsets, in patients with type I BD and healthy controls.

METHODS

Twenty-two euthymic female patients with BD type I and 17 age-matched healthy controls were selected for the study. A sample of blood was collected and mononuclear cells and DNA were isolated and TL measured. CMV immunoglobulin M (IgM) and IgG titers were measured using chemiluminescent assays. Lymphocyte subsets [T, natural killer (NK) and NKT] were phenotyped by flow cytometry.

RESULTS

Individuals with BD had shorter TLs but higher CMV IgG levels than controls (both p < 0.01). CMV IgG level was inversely correlated with TL. None of the subjects showed IgM reactivity for CMV, excluding acute viral infection. CMV IgG level was associated with expansion of senescent CD8+CD28- T cells and NK cells, which are involved in viral control.

CONCLUSIONS

These data support the hypothesis of accelerated aging in BD, as shown by shortened telomeres, higher seropositivity for CMV, and expansion of senescent T cells.

Reduced regulatory T cells are associated with higher levels of Th1/TH17 cytokines and activated MAPK in type 1 bipolar disorder

Bipolar disorder (BD) has been associated with an immunologic imbalance shown by increased peripheral inflammatory markers. The underlying mechanisms of this phenomenon may include changes in circulating cells and differential activation of mitogen-activated protein kinases (MAPKs). Twenty-seven euthymic female subjects with BD type I (all medicated) and 24 age- and sex-matched controls were recruited in this study. Lymphocytes were isolated and stimulated in vitro to assess Th1/Th17/Th2 cytokines (IL-2, IL-4, IL-6, IL-10, IL-17, IFN-γ and TNF-α) and MAPK phosphorylation. The expression of phospho-MAPKs, a large panel of lymphocyte subsets and cytokines were assessed by multi-color flow cytometry. BD patients had reduced proportions of natural T regulatory cells (CD4+ CD25+ FoxP3+) (p<0.01) in parallel to higher cytokine production (all p<0.01) than healthy controls. In particular, BD was associated with a strong bias to Th1 rather than Th2 profile. There was an expansion of senescence-associated cells (CD8+ CD28-) in BD (p<0.0001). T cells of BD patients had an increased p-ERK signaling (p<0.0001), indicating lymphocyte activation. Our data suggest that multiple molecular and cellular mechanisms may contribute to the immunologic imbalance observed in BD. In addition, our data concur to an early senescence process in these patients.

Neuroimmunoendocrine interactions in patients with recurrent major depression, increased early life stress and long-standing posttraumatic stress disorder symptoms

BACKGROUND

Traumatic events experienced in childhood may lead to psychiatric diseases in adult life, including major depressive disorder (MDD). It remains obscure to what extent early life stress (ELS) is associated with biologically relevant changes in MDD.

OBJECTIVE

We investigated both neuroendocrine and immunological correlates in recurrent MDD with ELS and current posttraumatic stress disorder symptoms.

METHODS

Thirty-eight female MDD patients with or without childhood trauma and 15 healthy controls took part in this study. Salivary cortisol and dehydroepiandrosterone sulfate (DHEAS) were assessed by radioimmunoassays. Peripheral blood mononuclear cells (PBMCs) were isolated and T cell proliferation and cellular sensitivity to steroids and DHEAS were evaluated by colorimetric assays. Th1/Th2 cytokines were assessed by cytometric bead arrays.

RESULTS

MDD patients with or without previous trauma had similarly lower salivary cortisol and DHEAS in parallel with blunted T cell proliferation. PBMCs of depressives were significantly less sensitive to dexamethasone or epinephrine than those of the controls. PBMCs of MDD patients produced significantly lower interleukin (IL)-2, IL-4 and tumor necrosis factor-α levels when compared to healthy controls.

CONCLUSION

We found that a history of ELS did not modify the blunted neuroendocrine and immunological alterations presented by recurrent depressed patients.