Notch Signaling is Required for Dendritic Cell Maturation and T Cell Expansion in Paracoccidioidomycosis

The Notch signaling pathway participates in several cellular functional aspects. This signaling has an important role in targeting both DC maturation and DC-mediated T cell responses. Thus, it is essential to investigate the influence of this signaling pathway in the role played by DCs in the pathogenesis of experimental paracoccidioidomycosis. This disease is a granulomatous and systemic mycosis that mainly affects lung tissue and can spread to any other organ and system. In this study, we demonstrated that bone marrow-derived DCs infected with yeasts from Paracoccidioides brasiliensis strain 18 performed efficiently their maturation after the activation of Notch signaling, with an increase in CD80, CD86, CCR7, and CD40 expression and the release of cytokines such as IL-6 and TNF-α. We observed that the inhibition of the γ-secretase DAPT impaired the proliferation of T cells induced by DC stimulation. In conclusion, our data suggest that Notch signaling contributes effectively to the maturation of DCs and the DC-mediated activation of the T cell response in P. brasiliensis infections.     

Extracellular N-acetylaspartate depletion in traumatic brain injury

N-Acetylaspartate (NAA) is almost exclusively localized in neurons in the adult brain and is present in high concentration in the CNS. It can be measured by proton magnetic resonance spectroscopy and is seen as a marker of neuronal damage and death. NMR spectroscopy and animal models have shown NAA depletion to occur in various types of chronic and acute brain injury. We investigated 19 patients with traumatic brain injury (TBI). Microdialysis was utilized to recover NAA, lactate, pyruvate, glycerol and glutamate, at 12-h intervals. These markers were correlated with survival and a 6-month Glasgow Outcome Score. Eleven patients died and eight survived. A linear mixed model analysis showed a significant effect of outcome and of the interaction between time of injury and outcome on NAA levels (p = 0.009 and p = 0.004, respectively). Overall, extracellular NAA was 34% lower in non-survivors. A significant non-recoverable fall was observed in this group from day 4 onwards, with a concomitant rise in lactate-pyruvate ratio and glycerol. These results suggest that mitochondrial dysfunction is a significant contributor to poor outcome following TBI and propose extracellular NAA as a potential marker for monitoring interventions aimed at preserving mitochondrial function.     

Cerato-platanin protein is located in the cell walls of ascospores, conidia and hyphae of Ceratocystis fimbriata f. sp. platani

Cerato-platanin (CP), a protein of about 12.4 kDa from Ceratocystis fimbriata f. sp. platani (Cfp), accumulated in the mycelium and was located in the cell walls of Cfp ascospores, hyphae and conidia suggesting that this protein had a role in forming the fungal cell wall apart from the already known fact that it is secreted early in culture and elicits phytoalexin synthesis and/or plant cell death. The finding was obtained with three immunological techniques: a quantitative ELISA which determines the amount of CP in the mycelium, an immunofluorescence assay, and immunogold labelling to define the exact localization of CP in the Cfp cells.     

Elevated blood Hsp60, its structural similarities and cross-reactivity with thyroid molecules,and its presence on the plasma membrane of oncocytes point to the chaperonin as an immunopathogenic factor in Hashimoto's thyroiditis

The role Hsp60 might play in various inflammatory and autoimmune diseases is under investigation, but little information exists pertaining to Hashimoto’s thyroiditis (HT). With the aim to fill this gap, in the present work, we directed our attention to Hsp60 participation in HT pathogenesis. We found Hsp60 levels increased in the blood of HT patients compared to controls. The chaperonin was immunolocalized in thyroid tissue specimens from patients with HT, both in thyrocytes and oncocytes (Hurthle cells) with higher levels compared to controls (goiter). In oncocytes, we found Hsp60 not only in the cytoplasm but also on the plasma membrane, as shown by double immunofluorescence performed on fine needle aspiration cytology. By bioinformatics, we found regions in the Hsp60 molecule with remarkable structural similarity with the thyroglobulin (TG) and thyroid peroxidase (TPO) molecules, which supports the notion that autoantibodies against TG and TPO are likely to recognize Hsp60 on the plasma membrane of oncocytes. This was also supported by data obtained by ELISA, showing that anti-TG and anti-TPO antibodies cross-react with human recombinant Hsp60. Antibody-antigen (Hsp60) reaction on the cell surface could very well mediate thyroid cell damage and destruction, perpetuating inflammation. Experiments with recombinant Hsp60 did not show stimulation of cytokine production by peripheral blood mononuclear cells from HT patients. All together, these results led us to hypothesize that Hsp60 may be an active player in HT pathogenesis via an antibody-mediated immune mechanism.     

Chiral introduction of positive charges to PNA for double-duplex invasion to versatile sequences

Invasion of two PNA strands to double-stranded DNA is one of the most promising methods to recognize a predetermined site in double-stranded DNA (PNA = peptide nucleic acid). In order to facilitate this 'double-duplex invasion', a new type of PNA was prepared by using chiral PNA monomers in which a nucleobase was bound to the alpha-nitrogen of N-(2-aminoethyl)-d-lysine. These positively charged monomer units, introduced to defined positions in Nielsen's PNAs (poly[N-(2-aminoethyl)glycine] derivatives), promoted the invasion without impairing mismatch-recognizing activity. When pseudo-complementary nucleobases 2,6-diaminopurine and 2-thiouracil were bound to N-(2-aminoethyl)-d-lysine, the invasion successfully occurred even at highly G-C-rich regions [e.g. (G/C)7(A/T)3 and (G/C)8(A/T)2] which were otherwise hardly targeted. Thus, the scope of sequences available as the target site has been greatly expanded. In contrast with the promotion by the chiral PNA monomers derived from N-(2-aminoethyl)-d-lysine, their l-isomers hardly invaded, showing crucial importance of the d-chirality. The promotion of double-duplex invasion by the chiral (d) PNA monomer units was ascribed to both destabilization of PNA/PNA duplex and stabilization of PNA/DNA duplexes.