Engineered dityrosine-bonding of the RSV prefusion F protein imparts stability and potency advantages.

Viral fusion proteins facilitate cellular infection by fusing viral and cellular membranes, which involves dramatic transitions from their pre- to postfusion conformations. These proteins are among the most protective viral immunogens, but they are metastable which often makes them intractable as subunit vaccine targets. Adapting a natural enzymatic reaction, we harness the structural rigidity that targeted dityrosine crosslinks impart to covalently stabilize fusion proteins in their native conformations. We show that the prefusion conformation of respiratory syncytial virus fusion protein can be stabilized with two engineered dityrosine crosslinks (DT-preF), markedly improving its stability and shelf-life. Furthermore, it has 11X greater potency as compared with the DS-Cav1 stabilized prefusion F protein in immunogenicity studies and overcomes immunosenescence in mice with simply a high-dose formulation on alum.

C-reactive protein and aetiological subtypes of cerebral infarction.

OBJECTIVE: We have sought to relate C-reactive protein (CRP), a peripheral marker of inflammation frequently elevated in stroke patients, with aetiology and prognosis of acute cerebral infarction. PATIENTS AND METHODS: Patients were included after a first-ever CT/MR documented cerebral infarction. CRP was measured from blood samples taken within the 6th hour of the onset. Titres of C-reactive protein were stratified in quartiles. Aetiology of stroke was from TOAST criteria. Prognosis was mortality within 14 days of stroke. RESULTS: The study included 648 stroke patients. They were 335 women and 313 men, with a mean age of 70.3 years (median 72). CRP quartiles were mostly increased in cardioembolic strokes, After logistic regression analysis CRP remained an independent factor of 14-day mortality. CONCLUSIONS: Our study suggests that in the acute phase of the cerebral infarction CRP might be either a marker of cardioembolism or a predictive factor for short-term mortality.

Spontaneous and prostatic steroid binding protein peptide-induced autoimmune prostatitis in the nonobese diabetic mouse.

Chronic nonbacterial prostatitis is a poorly defined syndrome of putative autoimmune origin. To further understand its pathogenesis, we have analyzed autoimmune prostatitis in the NOD mouse, a strain genetically prone to develop different organ-specific autoimmune diseases. Spontaneous development of autoimmune prostatitis in the NOD male, defined by lymphomonuclear cell infiltration in the prostate gland, is well-established by approximately 20 wk of age and is stably maintained afterward. Disease development is indistinguishable in NOD and NOR mice, but is markedly delayed in IFN-gamma-deficient NOD mice. A T cell response to the prostate-specific autoantigen prostatic steroid-binding protein (PSBP) can be detected in NOD males before development of prostate infiltration, indicating lack of tolerance to this self Ag. The intraprostatic inflammatory infiltrate is characterized by Th1-type CD4(+) T cells, which are able to transfer autoimmune prostatitis into NOD.SCID recipients. We characterize here experimental autoimmune prostatitis, detected by intraprostatic infiltrate and PSBP-specific T cell responses, induced in 6- to 8-wk-old NOD males by immunization with synthetic peptides corresponding to the C1 subunit of PSBP. Three PSBP peptides induce in NOD mice vigorous T and B cell responses, paralleled by a marked lymphomononuclear cell infiltration in the prostate. Two of these peptides, PSBP(21-40) and PSBP(61-80), correspond to immunodominant self epitopes naturally processed in NOD mice after immunization with PSBP, whereas peptide PSBP(91-111) represents a cryptic epitope. These model systems address pathogenetic mechanisms in autoimmune prostatitis and will facilitate testing and mechanistic analysis of therapeutic approaches in this condition.

Obesity surgery in a 12-year-old--an Ecuadorian experience.

The obesity epidemic is prevalent in Latin America. Our surgical team has had a significant number of consultations from parents and doctors of the obese child population. A case in a morbidly obese 12-year-old is hereby reported.

Inhibition of prostate growth and inflammation by the vitamin D receptor agonist BXL-628 (elocalcitol).

The prostate is a target organ of vitamin D receptor (VDR) agonists and represents an extra-renal site of 1,25-dihydroxyvitamin D(3) synthesis, but its capacity to respond to VDR agonists has, so far, been almost exclusively probed for the treatment of prostate cancer. We have analyzed the capacity of VDR agonists to treat benign prostatic hyperplasia (BPH), a complex syndrome characterized by a static component related to prostate overgrowth, a dynamic one responsible for urinary irritative symptoms, and an inflammatory component. Preclinical data demonstrate that VDR agonists, and notably BXL-628 (elocalcitol), reduce the static component of BPH by inhibiting the activity of intra-prostatic growth factors downstream of the androgen receptor, and the dynamic component by targeting bladder cells. In addition, BXL-628 inhibits production of proinflammatory cytokines and chemokines by human BPH cells. These data have led to a proof-of-concept clinical study that has successfully shown arrest of prostate growth in BPH patients treated with BXL-628, with excellent safety. We have documented the anti-inflammatory effects of BXL-628 also in animal models of autoimmune prostatitis, observing a significant reduction of intra-prostatic cell infiltrate following administration of this VDR agonist, at normocalcemic doses, in mice with already established disease. These data extend the potential use of VDR agonists to novel indications that represent important unmet medical needs, and provide a sound rationale for further clinical testing.

Calcitriol derivatives with two different side chains at C-20 III. An epimeric pair of the gemini family with unprecedented antiproliferative effects on tumor cells and renin mRNA expression inhibition.

The searches for drugs that exhibit antineoplastic activity and regulate blood pressure are among the most prevalent and compelling research activities today. Amazingly, there is ample precedence for the antiproliferative action of vitamin-D-related compounds and their role as endocrine suppressors of renin biosynthesis. We have recently synthesized a number of novel calcitriol analogs of the gemini family and originally selected for further studies an epimeric pair related to 19-nor-calcitriol whose 21-methyl group was replaced by a 5,5,5-trifluoro-4-hydroxy-4-(trifluoromethyl)-2-pentynyl group. While maintaining the acceptable calcemic responses, the IC50 concentrations of interferon-gamma release were reduced and the antiproliferative activity and inhibition of renin mRNA expression enhanced. Replacing the geminal methyl groups on the calcitriol-related side chain of these gemini compounds with trideuteriomethyl moieties further boosted the potency in the colon cancer model in mice some 10-fold, reduced NMU-induced breast cancer carcinogenesis in rats and decreased the IC(50) values for renin mRNA inhibition into the pM range.

Treatment of experimental autoimmune prostatitis in nonobese diabetic mice by the vitamin D receptor agonist elocalcitol.

On the basis of on the marked inhibitory activity of the vitamin D receptor agonist Elocalcitol on basal and growth factor-induced proliferation of human prostate cells and on its potent anti-inflammatory properties, we have tested its capacity to treat experimental autoimmune prostatitis (EAP) induced by injection of prostate homogenate-CFA in nonobese diabetic (NOD) mice. Administration of Elocalcitol, at normocalcemic doses, for 2 wk in already established EAP significantly inhibits the intraprostatic cell infiltrate, leading to a profound reduction in the number of CD4(+) and CD8(+) T cells, B cells, macrophages, dendritic cells, and I-A(g7)-positive cells. Immunohistological analysis demonstrates reduced cell proliferation and increased apoptosis of resident and infiltrating cells. Significantly decreased production of the proinflammatory cytokines IFN-gamma and IL-17 is observed in prostate-draining lymph node T cells from Elocalcitol-treated NOD mice stimulated by TCR ligation. In addition, Elocalcitol treatment reduces IFN-gamma production by prostate-infiltrating CD4(+) T cells and draining lymph node T cells specific for an immunodominant peptide naturally processed from prostate steroid-binding protein, a prostate-specific autoantigen. Finally, CD4(+) splenic T cells from Elocalcitol-treated NOD mice show decreased ability, upon adoptive transfer into NOD.SCID recipients, to induce autoimmune prostatitis, paralleled by a reduced capacity to produce IFN-gamma in response to prostate steroid-binding protein. The results indicate that Elocalcitol is able to interfere with key pathogenic events in already established EAP in the NOD mouse. These data show a novel indication for vitamin D receptor agonists and indicate that treatment with Elocalcitol may inhibit the intraprostatic inflammatory response in chronic prostatitis/chronic pelvic pain syndrome patients.

Odontologika

Traz informações sobre: periodontia, estética dental, implantes, cirurgia oral, clareamento, dor orofacial, endondontia, halitose, odontopedria, odontogeriatria, ordodontia, prótese, células-tronco entre outros temas. Apresenta também 3 seções: Atualidades, Orientações e Alternativos. Disponibiliza uma área intitulada News que apresenta notícias relacionadas à área de Odontologia.

APOBEC3B and APOBEC3C are potent inhibitors of simian immunodeficiency virus replication.

In the human genome the apolipoprotein B mRNA-editing enzyme catalytic polypeptide (APOBEC)3 gene has expanded into a tandem array of genes termed APOBEC3A-G. Two members of this family, APOBEC3G and APOBEC3F, have been found to have potent activity against virion infectivity factor deficient (Deltavif) human immunodeficiency virus 1 (HIV-1). These enzymes become encapsidated in Deltavif HIV-1 virions and in the next round of infection deaminate the newly synthesized reverse transcripts. The lentiviral Vif protein prevents the deamination by inducing the degradation of APOBEC3G and APOBEC3F. We report here that two additional APOBEC3 family members, APOBEC3B and APOBEC3C, have potent antiviral activity against simian immuno-deficiency virus (SIV), but not HIV-1. Both enzymes were encapsidated in HIV-1 and SIV virions and were active against Deltavif SIV(mac) and SIV(agm). SIV Vif neutralized the antiviral activity of APOBEC3C, but not that of APOBEC3B. APOBEC3B induced abundant G --> A mutations in both wild-type and Deltavif SIV reverse transcripts. APOBEC3C induced substantially fewer mutations. APOBEC3F was found to be active against SIV and sensitive to SIV(mac) Vif. These findings raise the possibility that the different APOBEC3 family members function to neutralize specific lentiviruses.

A vitamin D analog down-regulates proinflammatory chemokine production by pancreatic islets inhibiting T cell recruitment and type 1 diabetes development.

Type 1 diabetes (T1D) is an autoimmune disease characterized by leukocyte infiltration into the pancreatic islets, and we have previously shown that treatment of adult NOD mice with a vitamin D analog arrests the progression of insulitis, blocks Th1 cell infiltration into the pancreas, and markedly reduces T1D development, suggesting inhibition of chemokine production by islet cells. In this study, we show that all TLRs are expressed by mouse and human islet cells, and their engagement by pathogen-derived ligands markedly enhances proinflammatory chemokine production. The vitamin D analog significantly down-regulates in vitro and in vivo proinflammatory chemokine production by islet cells, inhibiting T cell recruitment into the pancreatic islets and T1D development. The inhibition of islet chemokine production in vivo persists after restimulation with TLR ligands and is associated with up-regulation of IkappaBalpha transcription, an inhibitor of NF-kappaB and with arrest of NF-kappaBp65 nuclear translocation, highlighting a novel mechanism of action exerted by vitamin D receptor ligands potentially relevant for the treatment of T1D and other autoimmune diseases.

Species-specific exclusion of APOBEC3G from HIV-1 virions by Vif.

The HIV-1 accessory protein Vif (virion infectivity factor) is required for the production of infectious virions by CD4(+) lymphocytes. Vif facilitates particle infectivity by blocking the inhibitory activity of APOBEC3G (CEM15), a virion-encapsidated cellular protein that deaminates minus-strand reverse transcript cytosines to uracils. We report that HIV-1 Vif forms a complex with human APOBEC3G that prevents its virion encapsidation. HIV-1 Vif did not efficiently form a complex with mouse APOBEC3G. Vif dramatically reduced the amount of human APOBEC3G encapsidated in HIV-1 virions but did not prevent encapsidation of mouse or AGM APOBEC3G. As a result, these enzymes are potent inhibitors of wild-type HIV-1 replication. The species-specificity of this interaction may play a role in restricting HIV-1 infection to humans. Together these findings suggest that therapeutic intervention that either induced APOBEC3G or blocked its interaction with Vif could be clinically beneficial.

Association of chemokine-mediated block to HIV entry with coreceptor internalization.

Chemokines inhibit entry of HIV into CD4(+) T cells more effectively than into macrophages or transfected adherent cells. Here, we tested whether chemokine receptor internalization could account for cell type differences in the effectiveness of chemokines. Infection of CEM T cells expressing stably transduced wild-type CCR5 was much more readily inhibited by chemokine than were transduced HOS cells. This response correlated with the efficiency of CCR5 internalization. A mutated CCR5, termed M7-CCR5, in which the Ser/Thr phosphorylation sites in the cytoplasmic tail were changed to Ala, did not internalize in response to MIP-1alpha. M7-CCR5 was expressed at slightly higher levels than wild-type on stably transduced cell lines and was somewhat more potent as an HIV-1 coreceptor. The mutated receptor mobilized intracellular Ca(2+) in response to chemokine to a level 4-fold higher than did the wild type CCR5. Unexpectedly, the receptor was desensitized as efficiently as wild type, suggesting that desensitization does not require cytoplasmic tail phosphorylation. Entry of R5 HIV-1 reporter virus into cells stably expressing M7-CCR5 was largely resistant to blocking by MIP-1alpha. As much as 80% of entry inhibition was attributed to receptor internalization. Aminooxypentane (AOP)-MIP-1alpha was able to induce a low level of M7-CCR5 internalization in HOS and to weakly inhibit HIV-1 entry. Introduction of dominant negative dynamin into HOS cells reduced the ability of chemokine to inhibit infection. The inefficiency of internalization of chemokine receptors in some cell types could allow virus to replicate in vivo in the presence of endogenous chemokine. Last, M7-CCR5 is a useful tool for discriminating coreceptor internalization from binding site masking in the evaluation of small molecule inhibitors of HIV-1 entry.

Chimeric human immunodeficiency virus type 1 containing murine leukemia virus matrix assembles in murine cells.

Murine cells do not support efficient assembly and release of human immunodeficiency virus type 1 (HIV-1) virions. HIV-1-infected mouse cells that express transfected human cyclin T1 synthesize abundant Gag precursor polyprotein, but inefficiently assemble and release virions. This assembly defect may result from a failure of the Gag polyprotein precursor to target to the cell membrane. Plasma membrane targeting of the precursor is mediated by the amino-terminal region of polyprotein. To compensate for the assembly block, we substituted the murine leukemia virus matrix coding sequences into an infectious HIV-1 clone. Transfection of murine fibroblasts expressing cyclin T1 with the chimeric proviruses resulted in viruses that were efficiently assembled and released. Chimeric viruses, in which the cytoplasmic tail of the transmembrane subunit, gp41, was truncated to prevent potential interference between the envelope glycoprotein and the heterologous matrix, could infect human and murine cells. They failed to further replicate in the murine cells, but replicated with delayed kinetics in human MT-4 cells. These findings may be useful for establishing a murine model for HIV-1 replication.