57 research outputs found
Paediatric HIV infection in the 'omics era: defining transcriptional signatures of viral control and vaccine responses
Modern technologies and their increased accessibility have shifted 'benchtop' medical research to the larger dimension of 'omics. The huge amount of data derived from gene expression and sequencing experiments has propelled physicians, basic scientists and bioinformaticians towards a common goal to transform 'big data' into predictive constructs that are readily available and will offer clinical utility. Although most of the studies available in the literature have been performed on healthy subjects and in peripheral blood mononuclear cells (PBMC), which are a heterogenous and extremely variable pool of cells, scientists are now trying to address mechanistic questions in purified cell subsets in pathological conditions. In the field of HIV, few attempts have been made to comprehensively evaluate gene-expression profiles of infected patients with different disease status. With the view of discovering a path towards remission or viral eradication, perinatally HIV-infected children represent a unique model. In fact the well-defined time of infection and the resulting opportunity to start early treatment, thereby generating a smaller size of viral reservoir and a more intact immune system, allow for investigation of therapeutic strategies to defeat the virus. In this scenario, 'transcriptomic' or gene expression technologies and supporting bioinformatics applications need to be strategically integrated to provide novel information about immune correlates of virus control following treatment interruption. Here we review modern techniques for gene expression analysis and discuss the best transcriptomic strategies applicable to the field of functional cure in paediatric HIV infection
Cyclic and Acyclic Defensins Inhibit Human Immunodeficiency Virus Type-1 Replication by Different Mechanisms
Defensins are antimicrobial peptides expressed by plants and animals. In mammals there are three subfamilies of defensins, distinguished by structural features: α, β and θ. Alpha and β-defensins are linear peptides with broad anti-microbial activity that are expressed by many mammals including humans. In contrast, θ-defensins are cyclic anti-microbial peptides made by several non-human primates but not humans. All three defensin types have anti-HIV-1 activity, but their mechanisms of action differ. We studied the anti-HIV-1 activity of one defensin from each group, HNP-1 (α), HBD-2 (β) and RTD-1 (θ). We examined how each defensin affected HIV-1 infection and demonstrated that the cyclic defensin RTD-1 inhibited HIV-1 entry, while acyclic HNP-1 and HBD-2 inhibited HIV-1 replication even when added 12 hours post-infection and blocked viral replication after HIV-1 cDNA formation. We further found that all three defensins downmodulated CXCR4. Moreover, RTD-1 inactivated X4 HIV-1, while HNP-1 and HBD-2 inactivated both X4 and R5 HIV-1. The data presented here show that acyclic and cyclic defensins block HIV-1 replication by shared and diverse mechanisms. Moreover, we found that HNP-1 and RTD-1 directly inhibited firefly luciferase enzymatic activity, which may affect the interpretation of previously published data
Albiglutide and cardiovascular outcomes in patients with type 2 diabetes and cardiovascular disease (Harmony Outcomes): a double-blind, randomised placebo-controlled trial
Background:
Glucagon-like peptide 1 receptor agonists differ in chemical structure, duration of action, and in their effects on clinical outcomes. The cardiovascular effects of once-weekly albiglutide in type 2 diabetes are unknown. We aimed to determine the safety and efficacy of albiglutide in preventing cardiovascular death, myocardial infarction, or stroke.
Methods:
We did a double-blind, randomised, placebo-controlled trial in 610 sites across 28 countries. We randomly assigned patients aged 40 years and older with type 2 diabetes and cardiovascular disease (at a 1:1 ratio) to groups that either received a subcutaneous injection of albiglutide (30–50 mg, based on glycaemic response and tolerability) or of a matched volume of placebo once a week, in addition to their standard care. Investigators used an interactive voice or web response system to obtain treatment assignment, and patients and all study investigators were masked to their treatment allocation. We hypothesised that albiglutide would be non-inferior to placebo for the primary outcome of the first occurrence of cardiovascular death, myocardial infarction, or stroke, which was assessed in the intention-to-treat population. If non-inferiority was confirmed by an upper limit of the 95% CI for a hazard ratio of less than 1·30, closed testing for superiority was prespecified. This study is registered with ClinicalTrials.gov, number NCT02465515.
Findings:
Patients were screened between July 1, 2015, and Nov 24, 2016. 10 793 patients were screened and 9463 participants were enrolled and randomly assigned to groups: 4731 patients were assigned to receive albiglutide and 4732 patients to receive placebo. On Nov 8, 2017, it was determined that 611 primary endpoints and a median follow-up of at least 1·5 years had accrued, and participants returned for a final visit and discontinuation from study treatment; the last patient visit was on March 12, 2018. These 9463 patients, the intention-to-treat population, were evaluated for a median duration of 1·6 years and were assessed for the primary outcome. The primary composite outcome occurred in 338 (7%) of 4731 patients at an incidence rate of 4·6 events per 100 person-years in the albiglutide group and in 428 (9%) of 4732 patients at an incidence rate of 5·9 events per 100 person-years in the placebo group (hazard ratio 0·78, 95% CI 0·68–0·90), which indicated that albiglutide was superior to placebo (p<0·0001 for non-inferiority; p=0·0006 for superiority). The incidence of acute pancreatitis (ten patients in the albiglutide group and seven patients in the placebo group), pancreatic cancer (six patients in the albiglutide group and five patients in the placebo group), medullary thyroid carcinoma (zero patients in both groups), and other serious adverse events did not differ between the two groups. There were three (<1%) deaths in the placebo group that were assessed by investigators, who were masked to study drug assignment, to be treatment-related and two (<1%) deaths in the albiglutide group.
Interpretation:
In patients with type 2 diabetes and cardiovascular disease, albiglutide was superior to placebo with respect to major adverse cardiovascular events. Evidence-based glucagon-like peptide 1 receptor agonists should therefore be considered as part of a comprehensive strategy to reduce the risk of cardiovascular events in patients with type 2 diabetes.
Funding:
GlaxoSmithKline
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Characterization of Perforin-2, a Novel Anti-bacterial, Pore-forming Protein of the Innate Immune System
Pore-forming proteins such as the membrane attack complex (MAC) of the complement system and Perforin of cytotoxic lymphocytes are potent host defense effectors employed by the immune system. These proteins share a structurally conserved domain, MACPF that is responsible for ring formation and membrane insertion of these toxic molecules. The objective of the current study was to identify the function of a third MACPF-containing pore-former of the immune system, Macrophage expressed gene 1 (Mpeg1). Mpeg1 encodes a highly conserved, membrane-bound protein which we have designated Perforin-2 (P-2). P-2 is induced upon monocyte maturation, is constitutively expressed by macrophages and upregulated by lipopolysaccharides (LPS) and interferon-gamma (IFN-gamma). Evidence is presented herein that macrophages employ P-2 to mediate intracellular killing of bacteria. Gene silencing was performed using P-2-specific siRNA which led to uncontrolled Salmonella typhimurium growth. To further characterize the protein, a P-2 fusion protein with a fluorescent tag was transfected into macrophages and analyzed for localization and function. P-2 in macrophages resides in the endoplasmic reticulum, Golgi network and recycling endosomes where it would be available for trafficking to phagocytosed microbes. Combined inhibition of the established bactericidal mechanisms, reactive oxygen species and nitric oxide, with P-2 resulted in bacterial survival equal to that of P-2 inhibition alone suggesting that oxidative pathways of toxicity are downstream of P-2 action. Finally, site-directed mutagenesis of a conserved tyrosine in the cytoplasmic domain of P-2 rendered the protein non-functional in killing against Mycobacterium smegmatis suggesting that phosphorylation of this residue is important for activation of P-2. Therefore, P-2 represents a novel, highly conserved cytotoxic effector molecule expressed by macrophages with important implications for the control of microbial infection and host defense.</p
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Supplemental Files_Xiao et al., JDS19497
Supplemental files for the publication Xiao et al., "An improved method for specific-target preamplification PCR analysis of single blastocysts useful for embryo sexing and high-throughput gene expression analysis" (doi: 10.3168/jds.2020-19497)
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Is It Possible to Distinguish Between Vasoplegic Syndrome and Postreperfusion Syndrome During Liver Graft Reperfusion?
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Characerization of a novel pore‐forming protein in macrophages
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A new species of Piaroa (Schizomida: Hubbardiidae) from Venezuela, with taxonomic notes on the genus
A new species belonging to the schizomid genus Piaroa Villarreal, Giupponi and Tourinho, 2008 is described from north-western Venezuela. A complementary description of Piaroa guipongai Villarreal and Garcia, 2012 is provided including SEM pictures of relevant structures of both sexes. A key for males of Piaroa and Colombiazomus Armas and Delgado-Santa, 2012 is included. The presence of Dm3 setae on Hubbardiidae is discussed
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Chapter Sixteen - Natural killer cytolytic activity
Natural killer (NK)–mediated cellular killing has been extensively studied over the past 35 years and the current “granule exocytosis” model integrates work from many investigators to outline the primary means of NK cytotoxicity. A secondary pathway is mediated through so-called death-receptors, and exhibits less relevance for host defense against pathogens in vivo but is important for the elimination of auto-reactive lymphoid cells and also homeostasis. NK cells directly execute the destruction of both autologous and allogeneic cells. NK cytotoxicity has a direct role in host defense and immunopathology in response to viral infection and malignant transformation. NK cells are heralded as the first wave of defense against a variety of pathogens in which they employ potent weaponry to kill infected and malignant cells. In addition to killing these “stressed” cells, NK are implicated in the elimination of autologous activated immune cells (T cells and macrophages) following an inflammatory response. Furthermore, NK are critical producers of cytokines, most notably the pro-inflammatory interferon-γ (IFN-γ), which has pleiotropic effects on cells that modulate the adaptive immune response. NK cells are the innate constituents of cytotoxic lymphocytes and they utilize identical cytolytic pathways as the CD8+ cytotoxic T lymphocytes (CTL), namely via granule exocytosis and death-receptor mediated killing. NK cells are considered part of the innate immune system due to their germ-line encoded, early and rapid cytolytic response to a diverse array of pathogens, although they do not kill “non-specifically”. The simple fact that NK cytotoxicity can cause cell death demands strict regulation upon the activation of NK by potential target cells
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