Publications by authors named "Petros C Karakousis"

Tuberculosis (TB) necrotic granulomas contain triglyceride-rich macrophages (foam cells) with reduced antimicrobial functions. We assessed the ability of two compounds to reduce triglyceride content and Mycobacterium tuberculosis (Mtb) burden in infected human monocyte-derived macrophages and in the lungs of Mtb-infected C3HeB/FeJ mice: A-922500 (DGATi), an inhibitor of diacylglycerol acyltransferase 1; and LY2584702 (p70S6Ki), an inhibitor of p70 S6 kinase. DGATi and p70S6Ki significantly reduced the lipid content and bacillary burden in Mtb-infected macrophages.

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Previous studies in the B16F10 mouse melanoma model have demonstrated that combining a DNA vaccine comprised of regions of gp100 and tyrosinase-related protein 2 fused to macrophage-inflammatory protein 3-alpha (MIP3α) with recombinant interferon alpha (IFN) and 5-Aza-2'-deoxycytidine (5Aza) treatments resulted in significantly greater antitumor activity and immunogenicity in the tumor microenvironment (TME). This brief report details that the combination of vaccine with treatments IFN and 5Aza results in an increase in the TME of a distinct CD11c+ CD8+ T-cell population. This cell population correlates with tumor size, is primarily comprised of effector or effector memory T cells, and has a more robust response to ex vivo stimulation as compared with CD11c- CD8+ T cells.

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Tuberculosis (TB) remains among the leading infectious causes of death. Due to the limited number of antimicrobials in the TB drug discovery pipeline, interest has developed in host-directed approaches to improve TB treatment outcomes. C-C motif chemokine-like receptor 2 (CCRL2) is a unique seven-transmembrane domain receptor that is upregulated by inflammatory signals and mediates leucocyte migration.

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Although tuberculosis is an ancient disease, recognition of its airborne route of transmission, with implications for respiratory isolation, is only relatively recent. Since the time of Hippocrates, the dogma among health practitioners was that the disease was hereditary or that it could be contracted by inhaling "miasma", or corrupted air. Consequently, isolation of patients was not routine practice, and, in fact, patients with scrofula (morbus regius, or "king's evil) sought to be cured by the "royal touch" throughout the middle ages.

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Unlabelled: Mtb) is one of the leading infectious causes of death worldwide. There is no available licensed therapeutic vaccine that shortens active tuberculosis (TB) disease drug treatment and prevents relapse, despite the World Health Organization's calls. Here, we show that an intranasal DNA vaccine containing a fusion of the stringent response gene with the gene encoding the immature dendritic cell-targeting chemokine, MIP-3α/CCL20, shortens the duration of curative TB treatment in immunocompetent mice.

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(Mtb), the causative agent of tuberculosis (TB), is the leading cause of mortality due to a single infectious organism. While generally curable, TB requires a lengthy and complex antibiotic regimen, due in large part to bacteria that can shift to a persistent state in the presence of antibiotic pressure. Rel is the primary enzyme regulating the stringent response, which contributes to the metabolic shift of Mtb to a persistent state.

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Unlabelled: The pathogenesis of COVID-19 is associated with a hyperinflammatory immune response. Monocytes and macrophages play a central role in this hyperinflammatory response to SARS-CoV-2. NLRP3 inflammasome activation has been observed in monocytes of patients with COVID-19, but the mechanism and consequences of inflammasome activation require further investigation.

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The incidence of atherosclerotic cardiovascular disease is increasing globally, especially in low- and middle-income countries, despite significant efforts to reduce traditional risk factors. Premature subclinical atherosclerosis has been documented in association with several viral infections. The magnitude of the recent COVID-19 pandemic has highlighted the need to understand the association between SARS-CoV-2 and atherosclerosis.

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Background: Previous studies have demonstrated enhanced efficacy of vaccine formulations that incorporate the chemokine macrophage inflammatory protein 3α (MIP-3α) to direct vaccine antigens to immature dendritic cells. To address the reduction in vaccine efficacy associated with a mutation in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mutants, we have examined the ability of receptor-binding domain vaccines incorporating MIP-3α to sustain higher concentrations of antibody when administered intramuscularly (IM) and to more effectively elicit lung T-cell responses when administered intranasally (IN).

Methods: BALB/c mice aged 6-8 weeks were immunized intramuscularly or intranasally with DNA vaccine constructs consisting of the SARS-CoV-2 receptor-binding domain alone or fused to the chemokine MIP-3α.

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Multidrug-resistant (MDR) (Mtb) poses significant challenges to global tuberculosis (TB) control efforts. Host-directed therapies (HDTs) offer a novel approach to TB treatment by enhancing immune-mediated clearance of Mtb. Prior preclinical studies found that the inhibition of heme oxygenase-1 (HO-1), an enzyme involved in heme metabolism, with tin-protoporphyrin IX (SnPP) significantly reduced mouse lung bacillary burden when co-administered with the first-line antitubercular regimen.

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The convergence of Human Immunodeficiency Virus (HIV) and tuberculosis (TB) represents a considerable global public health challenge. The concurrent infection of HIV and TB in pregnant women not only intensifies the transmission of HIV from mother to fetus but also engenders adverse outcomes for maternal health, pregnancy, and infant well-being, necessitating the implementation of integrated strategies to effectively address and manage both diseases. In this article, we review the pathophysiology, clinical presentation, treatment, and management of HIV/TB coinfection during pregnancy, the postpartum period, and lactation and highlight the differences compared to the general population.

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Article Synopsis
  • The bacterium that causes tuberculosis, a significant global health issue, is responsible for over a million deaths annually, highlighting the need for shorter and simpler treatment options.
  • Research shows that this bacterium can adapt its metabolism during nutrient starvation, which occurs during infection, allowing it to withstand standard antibiotic treatments.
  • A genetic study identified 220 mutant strains of the bacterium with different responses to key antibiotics, revealing several genes that may serve as potential therapeutic targets to improve treatment effectiveness.
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Previous studies in the B16F10 mouse melanoma model have demonstrated that combining a DNA vaccine comprised of regions of gp100 and tyrosinase-related protein 2 fused to Macrophage-inflammatory protein 3-alpha (MIP3α) with recombinant Interferon alpha (IFN) and 5-Aza-2'-Deoxycytidine (5Aza) treatments resulted in significantly greater anti-tumor activity and immunogenicity in the tumor microenvironment (TME). This brief report details that the combination of vaccine with treatments IFN and 5Aza results in both the upregulation of genes expressing CD11c-interacting proteins and an increase in the TME of a distinct CD11c+ CD8+ T cell population. This cell population correlates with tumor size, is primarily comprised of effector or effector memory T cells, and has a more robust response to ex vivo stimulation as compared to CD11c- CD8+ T cells as measured by surface activation markers 4-1BB (CD137) and KLRG1 (Killer cell lectin-like receptor G1) and intracellular IFNγ production.

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Multidrug-resistant (MDR) (Mtb) poses significant challenges to global tuberculosis (TB) control efforts. Host-directed therapies (HDT) offer a novel approach for TB treatment by enhancing immune-mediated clearance of Mtb. Prior preclinical studies found that inhibition of heme oxygenase-1 (HO-1), an enzyme involved in heme metabolism, with tin-protoporphyrin IX (SnPP) significantly reduced mouse lung bacillary burden when co-administered with the first-line antitubercular regimen.

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Article Synopsis
  • * The study focused on understanding how the bacterium adapts to nutrient starvation during infection, which helps it survive against antibiotics like rifampin and isoniazid, by conducting a genetic screen to identify related genes.
  • * Researchers discovered 220 mutants with different antibiotic responses under nutrient-rich conditions and 82 mutants under nutrient-starved conditions, revealing promising genetic targets that may contribute to more effective and shorter TB treatments.
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Introduction: DNA vaccines containing a fusion of the gene encoding chemokine MIP-3α (CCL20), the ligand for CCR6 on immature dendritic cells (DCs), to melanoma-associated antigen genes have enhanced anti-tumor immunity and efficacy compared to those lacking the chemokine gene. Previous work has shown that type-I interferon (IFNα or IFN) and 5-Aza-2'-deoxycytidine (5Aza) significantly enhance the therapeutic benefit of DNA vaccines as measured by reduced tumor burden and improved mouse survival.

Methods: Here, we explored mouse intratumoral immune correlates underlying the therapeutic benefit of this combination regimen (vaccine, IFN, and 5Aza) as compared to vaccine alone and IFN and 5Aza without vaccine, focusing on chemokine mRNA expression by qRT-PCR and inflammatory cellular infiltration into the tumor microenvironment (TME) by flow cytometry and immunohistochemistry (IHC).

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Objectives: Bone tuberculosis (TB) is the third most common types of extrapulmonary tuberculosis. It is critical to understand mycobacterial adaptive strategies within bone lesions to identify mycobacterial factors that may have role in disease pathogenesis.

Methods: Whole genome microarray was used to characterize the in-vivo transcriptome of Mycobacterium tuberculosis (M.

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Article Synopsis
  • Treating tuberculosis (TB) takes a long time because some germs can hide from medicines, so researchers are trying new ways to help fight it.
  • They created a special DNA vaccine that helps the immune system target the TB germs better, using a method that involves delivering it through the nose.
  • Their tests showed that this new vaccine worked really well, helping reduce the number of TB germs much more than traditional methods on their own, which could make curing TB faster and could be used for other stubborn infections too!
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Background: Host cell-membrane cholesterol, an important player in viral infections, is in constant interaction with serum high-density lipoprotein-cholesterol (HDL-C) and low-density lipoprotein-cholesterol (LDL-C). Low serum lipid levels during hospital admission are associated with COVID-19 severity. However, the effect of antecedent serum lipid levels on SARS-CoV-2 infection risk has not been explored.

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Background: Coronavirus disease 2019 (COVID-19) ranges from asymptomatic infection to severe illness. Cholesterol in the host cell plasma membrane plays an important role in the SARS-CoV-2 virus entry into cells. Serum lipids, especially low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C), are in constant interaction with the lipid rafts in the host cell membranes and can modify the interaction of virus with host cells and the resultant disease severity.

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Objectives: Pediatric tuberculosis (TB) remains difficult to diagnose. The plasma kynurenine to tryptophan ratio (K/T ratio) is a potential biomarker for TB diagnosis and treatment response but has not been assessed in children.

Methods: We performed a targeted diagnostic accuracy analysis of four biomarkers: kynurenine abundance, tryptophan abundance, the K/T ratio, and IDO-1 gene expression.

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To catalyze severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) research, including development of novel interventive and preventive strategies, the progression of disease was characterized in a robust coronavirus disease 2019 (COVID-19) animal model. In this model, male and female golden Syrian hamsters were inoculated intranasally with SARS-CoV-2 USA-WA1/2020. Groups of inoculated and mock-inoculated uninfected control animals were euthanized at 2, 4, 7, 14, and 28 days after inoculation to track multiple clinical, pathology, virology, and immunology outcomes.

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The stringent response is well conserved across bacterial species and is a key pathway involved both in bacterial survival and virulence and in the induction of antibiotic tolerance in Mycobacteria. It is mediated by the alarmone (p)ppGpp and the regulatory molecule inorganic polyphosphate in response to stress conditions such as nutrient starvation. Efforts to pharmacologically target various components of the stringent response have shown promise in modulating mycobacterial virulence and antibiotic tolerance.

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Objective: This study sought to evaluate the utility of the Global Health Security (GHS) index in predicting the launch of COVID-19 vaccine rollout by Organization for Economic Cooperation and Development (OECD) member countries.

Methods: Country-level data on the preparedness to respond to infectious disease threats through vaccination rollout were collected using the GHS index. OECD member countries were rank-ordered based on the percentage of their populations fully vaccinated against COVID-19.

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