Identification of new HIV-1 Gag-specific cytotoxic T lymphocyte responses in BALB/c mice

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HIV-1 Tat protein modulates the generation of cytotoxic T cell epitopes by modifying proteasome composition and enzymatic activity

Tat, the trans activation protein of HIV, is produced early upon infection to promote and expand HIV replication and transmission. However, Tat appears to also have effects on target cells, which may affect Ag recognition both during infection and after vaccination. In particular, Tat targets dendritic cells and induces their maturation and Ag-presenting functions, increasing Th1 T cell responses. We show in this work that Tat modifies the catalytic subunit composition of immunoproteasomes in B and T cells either expressing Tat or treated with exogenous biological active Tat protein. In particular, Tat up-regulates latent membrane protein 7 and multicatalytic endopeptidase complex like-1 subunits and down-modulates the latent membrane protein 2 subunit. These changes correlate with the increase of all three major proteolytic activities of the proteasome and result in a more efficient generation and presentation of subdominant MHC-I-binding CTL epitopes of heterologous Ags. Thus, Tat modifies the Ag processing and modulates the generation of CTL epitopes. This may have an impact on both the control of virally infected cells during HIV-1 infection and the use of Tat for vaccination strategies

Pulsed Electromagnetic Fields Stimulate Osteogenic Differentiation in Human Bone Marrow and Adipose Tissue Derived Mesenchymal Stem Cells

Pulsed electromagnetic fields (PEMFs) play a regulatory role on osteoblast activity and are clinically beneficial during fracture healing. Human mesenchymal stem cells (MSCs) derived from different sources have been extensively used in bone tissue engineering. Compared with MSCs isolated from bone marrow (BMSCs), those derived from adipose tissue (ASCs) are easier to obtain and available in larger amounts, although they show a less osteogenic differentiation potential than BMSCs. The hypothesis tested in this study was to evaluate whether PEMFs favor osteogenic differentiation both in BMSCs and in ASCs and to compare the role of PEMFs alone and in combination with the biochemical osteogenic stimulus bone morphogenetic protein (BMP)-2. Early and later osteogenic markers, such as alkaline phosphatase (ALP) activity, osteocalcin levels, and matrix mineralization, were analyzed at different times during osteogenic differentiation. Results showed that PEMFs induced osteogenic differentiation by increasing ALP activity, osteocalcin, and matrix mineralization in both BMSCs and ASCs, suggesting that PEMF activity is maintained during the whole differentiation period. The addition of BMP-2 in PEMF exposed cultures further increased all the osteogenic markers in BMSCs, while in ASCs, the stimulatory role of PEMFs was independent of BMP-2. Our results indicate that PEMFs may stimulate an early osteogenic induction in both BMSCs and ASCs and they suggest PEMFs as a bioactive factor to enhance the osteogenesis of ASCs, which are an attractive cell source for clinical applications. In conclusion, PEMFs may be considered a possible tool to improve autologous cell-based regeneration of bone defects in orthopedics

The role of Notch pathway in cardiovascular diseases.

none7The recent increase in human lifespan, coupled with unhealthy diets and lifestyles have led to an unprecedented increase in cardiovascular diseases. Even in the presence of a wide range of therapeutic options with variable efficacy, mortality due to heart failure is still high and there is a need to identify new therapeutic targets. Genetic and in vitro studies have implicated the Notch signalling in the development and maintenance of the cardiovascular system through a direct effect on biological functions of vascular cells (endothelial and vascular smooth muscle cells) and cardiomyocytes. Notch signalling is also involved in the modulation of inflammation, which plays a major role in causing and exacerbating cardiovascular diseases. The Notch pathway could represent a new therapeutic target for the treatment of cardiovascular diseases.noneAquila G;Pannella M;Morelli MB;Caliceti C;Fortini C;Rizzo P;Ferrari RAquila, Giorgio; Pannella, Micaela; Morelli, Marco Bruno; Caliceti, Cristiana; Fortini, Cinzia; Rizzo, Paola; Ferrari, Robert

The role of Notch pathway in cardiovascular diseases

The recent increase in human lifespan, coupled with unhealthy diets and lifestyles have led to an unprecedented increase in cardiovascular diseases. Even in the presence of a wide range of therapeutic options with variable efficacy, mortality due to heart failure is still high and there is a need to identify new therapeutic targets. Genetic and in vitro studies have implicated the Notch signalling in the development and maintenance of the cardiovascular system through a direct effect on biological functions of vascular cells (endothelial and vascular smooth muscle cells) and cardiomyocytes. Notch signalling is also involved in the modulation of inflammation, which plays a major role in causing and exacerbating cardiovascular diseases. The Notch pathway could represent a new therapeutic target for the treatment of cardiovascular diseases

Distinct gene expression profiles associated with Notch ligands Delta-like 4 and Jagged1 in plaque material from peripheral artery disease patients: A pilot study

Background: The lack of early diagnosis, progression markers and effective pharmacological treatment has dramatic unfavourable effects on clinical outcomes in patients with peripheral artery disease (PAD). Addressing these issues will require dissecting the molecular mechanisms underlying this disease. We sought to characterize the Notch signaling and atherosclerosis relevant markers in lesions from femoral arteries of symptomatic PAD patients. Methods: Plaque material from the common femoral, superficial femoral or popliteal arteries of 20 patients was removed by directional atherectomy. RNA was obtained from 9 out of 20 samples and analysed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Results: We detected expression of Notch ligands Delta-like 4 (Dll4) and Jagged1 (Jag1), of Notch target genes Hes1, Hey1, Hey2, HeyL and of markers of plaque inflammation and stability such as vascular cell adhesion molecule 1 (VCAM1), smooth muscle 22 (SM22), cyclooxygenase 2 (COX2), Bcl2, CD68 and miRNAs 21-5p, 125a-5p, 126-5p,146-5p, 155-5p, 424-5p. We found an "inflamed plaque" gene expression profile characterized by high Dll4 associated to medium/high CD68, COX2, VCAM1, Hes1, miR126-5p, miR146a-5p, miR155-5p, miR424-5p and low Jag1, SM22, Bcl2, Hey2, HeyL, miR125a-5p (2/9 patients) and a "stable plaque" profile characterized by high Jag1 associated to medium/high Hey2, HeyL, SM22, Bcl2, miR125a and low Dll4, CD68, COX2, VCAM1, miR126-5p, miR146a-5p, miR155-5p, miR424-5p (3/9 patients). The remaining patients (4/9) showed a plaque profile with intermediate characteristics. Conclusions: This study reveals the existence of a gene signature associated to Notch activation by specific ligands that could be predictive of PAD progression

Expression of A3 adenosine receptors in human lymphocytes: up-regulation in T cell activation

The present study investigates mRNA and protein levels of A3 adenosine receptors in resting (R) and activated (A) human lymphocytes. The receptors were evaluated by the antagonist radioligand [3H]5-N-(4-methoxyphenyl-carbamoyl)amino-8-propyl-2(2furyl)-pyrazolo-[4,3e]-1,2,4-triazolo-[1,5-c]-pyrimidine ([3H]MRE 3008F20), which yielded Bmax values of 125 +/- 15 and 225 +/- 23 fmol/mg of protein and KD values of 1.79 +/- 0.30 and 1.85 +/- 0.25 nM in R and A cells, respectively. The protein seems to be induced with remarkable rapidity starting at 15 min and reaches a plateau at 30 min. Western blot assays revealed that the up-regulation of the A3 subtype after lymphocyte activation was caused by an increase in an enriched CD4+ cell fraction. Real-time reverse transcription-polymerase chain reaction experiments confirmed the rapid increase of A3 mRNA after T cell activation. Competition of radioligand binding by adenosine ligands displayed a rank order of potency typical of the A3 subtype. Thermodynamic data indicated that the binding is enthalpy- and entropy-driven in both R and A cells, suggesting that the activation process does not involve, at a molecular level, receptor alterations leading to modifications in the A3-related binding mechanisms. Functionally, the up-regulation of A3 adenosine receptors in A versus R cells corresponded to a potency increase of the A3 agonist N6-(3-iodo-benzyl)-2-chloro-adenosine-5'-N-methyluronamide in inhibiting cAMP accumulation (IC50=1.5 +/- 0.4 and 2.7 +/- 0.3 nM, respectively); this effect was antagonized by MRE 3008F20 (IC50=5.0 +/- 0.3 nM). In conclusion, our results provide, for the first time, an in-depth investigation of A3 receptors in human lymphocytes and demonstrate that, under activating conditions, they are up-regulated and may contribute to the effects triggered by adenosine

Immunological modifications during treatment with tymosin alpha 1 plus antiviral therapy in chronic hepatitis C

The current standard therapy for the treatment of Chronic Hepatitis C is the combination of peginterferon and ribavirin, although many patients fail to clear the virus and their retreatment options are still unsatisfactory. Thymosin 1 (T1) is an immunomodulating agent which has been proposed as complementary therapy for chronic HCV especially in the setting of difficult-to-treat patients. The aim of this study was to evaluate, in patients non responders to previous Peg-based therapy, the effect of standard antiviral therapy with or without T1 on peripheral lymphocytes subsets. Twenty-four patients, 12 receiving T1 and 12 standard therapy, were enrolled. Peripheral subpopulations were analyzed by flow cytometry. While the addition of T1 did not seem to significantly modify the T lymphocyte subpopulations, since comparable behaviors were observed in the CD4 and CD8 longitudinal evaluation, T1 produced an earlier increase of NK cells. An accurate selection of HCV patients who can benefit from immunomodulation is needed