Lethal Synergism Research Articles

Neutralizing Nanobodies against Venoms from Naja haje Species Captured in North Africa.

Snakebite envenoming (SBE) remains a severely neglected public health issue, particularly affecting tropical and subtropical regions, with Africa experiencing an estimated 435,000 to 580,000 snakebites annually, leading to high morbidity and mortality rates, especially across Africa and Asia. Recognized as a Neglected Tropical Disease, SBE management is further complicated by the inadequate efficacy of current antivenom treatments. Of particular concern are cobras (Naja sp.), whose neurotoxins can induce rapid fatal respiratory paralysis. In this study, we investigate the potential of nanobodies as a promising next-generation of immunotherapeutics against cobra venoms. Through a dual strategy of the characterization of venom toxic fractions from cobras captured for the first time in Algeria and Tunisia biotopes, coupled with in vitro assays to evaluate their interactions with acetylcholine receptors, and subsequent immunization of dromedaries to produce specific nanobodies, we identified two lethal fractions, F5 and F6, from each venom, and selected five nanobodies with significant binding and neutralizing of 3DL50 (0.74 mg/kg). The combination of these nanobodies demonstrated a synergistic effect, reaching 100% neutralizing efficacy of 2DL50 lethal venom fraction (0.88 mg/kg) doses in mice. Additionally, our findings highlighted the complex mechanism of cobra venom action through the lethal synergism among its major toxins.

A fungal metabolic regulator underlies infectious synergism during Candida albicans-Staphylococcusaureus intra-abdominal co-infection

Candida albicans and Staphylococcus aureus are two commonly associated pathogens that cause nosocomial infections with high morbidity and mortality. Our prior and current work using a murine model of polymicrobial intra-abdominal infection (IAI) demonstrates that synergistic lethality is driven by Candida-induced upregulation of functional S. aureus α-toxin leading to polymicrobial sepsis and organ damage. In order to determine the candidal effector(s) mediating enhanced virulence, an unbiased screen of C. albicans transcription factor mutants was undertaken revealing that zcf13Δ/Δ fails to drive augmented α-toxin or lethal synergism during co-infection. A combination of transcriptional and phenotypic profiling approaches shows that ZCF13 regulates genes involved in pentose metabolism, including RBK1 and HGT7 that contribute to fungal ribose catabolism and uptake, respectively. Subsequent experiments reveal that ribose inhibits the staphylococcal agr quorum sensing system and concomitantly represses toxicity. Unlike wild-type C. albicans, zcf13Δ/Δ did not effectively utilize ribose during co-culture or co-infection leading to exogenous ribose accumulation and agr repression. Forced expression of RBK1 and HGT7 in the zcf13Δ/Δ mutant fully restores pathogenicity during co-infection. Collectively, our results detail the interwoven complexities of cross-kingdom interactions and highlight how intermicrobial metabolism impacts polymicrobial disease pathogenesis with devastating consequences for the host.

Mathematical Modeling of the Lethal Synergism of Coinfecting Pathogens in Respiratory Viral Infections: A Review.

Influenza A virus (IAV) infections represent a substantial global health challenge and are often accompanied by coinfections involving secondary viruses or bacteria, resulting in increased morbidity and mortality. The clinical impact of coinfections remains poorly understood, with conflicting findings regarding fatality. Isolating the impact of each pathogen and mechanisms of pathogen synergy during coinfections is challenging and further complicated by host and pathogen variability and experimental conditions. Factors such as cytokine dysregulation, immune cell function alterations, mucociliary dysfunction, and changes to the respiratory tract epithelium have been identified as contributors to increased lethality. The relative significance of these factors depends on variables such as pathogen types, infection timing, sequence, and inoculum size. Mathematical biological modeling can play a pivotal role in shedding light on the mechanisms of coinfections. Mathematical modeling enables the quantification of aspects of the intra-host immune response that are difficult to assess experimentally. In this narrative review, we highlight important mechanisms of IAV coinfection with bacterial and viral pathogens and survey mathematical models of coinfection and the insights gained from them. We discuss current challenges and limitations facing coinfection modeling, as well as current trends and future directions toward a complete understanding of coinfection using mathematical modeling and computer simulation.

Chloroquine inhibits pro-inflammatory effects of heme on macrophages and invivo

BackgroundChloroquine has been used successfully to treat Malaria, including by chloroquine-resistant Plasmodium sp., indicating that it has effects on disease itself. Since heme has inflammatory effects and contributes to the pathogenesis of hemolytic diseases, we hypothesize that the anti-inflammatory effect of chloroquine is partially due to its inhibitory effect on heme-induced macrophage activation and on inflammatory tissue damage. MethodsBone marrow derived macrophages (BMDMs) were incubated with chloroquine before stimulation with heme, in different conditions, to evaluate cytokines secretion, ROS production, mitogen activated protein kinases (MAPK) or spleen tyrosine kinase (Syk) activation, alone or combined with LPS. The effects of chloroquine upon heme inflammation were also evaluated in vivo, through simultaneous i.p. injection of LPS and heme, intratracheal instillation of Poly-IC followed by heme injection, and in a rhabdomyolysis model. ResultsChloroquine inhibited TNF secretion, mitochondrial ROS production, MAPK, and Syk activation induced by heme. Inhibition of TNF production could be mimicked by zinc ionophore quercetin, but not by primaquine, a chloroquine analog with low affinity for heme. IL-6 and IL-1β secretions induced by heme in the presence of PRRs agonists were inhibited by chloroquine, but not by calcium chelator BAPTA or inhibitor of endosomal acidification concamycin B. Chloroquine also protected mice from heme inflammatory effects in vivo, inhibiting lethal synergism with PRR agonists, lung pathology caused by heme injection after intratracheal instillation of Poly-IC, and delaying death after rhabdomyolisis. ConclusionOur data indicate that chloroquine might be used as a supportive therapy to control heme-induced deleterious inflammation in different hemolytic diseases.

A Retrospective Study of Coinfection of SARS-CoV-2 and Streptococcus pneumoniae in 11 Hospitalized Patients with Severe COVID-19 Pneumonia at a Single Center.

BackgroundA lethal synergism between the influenza virus and Streptococcus pneumoniae has been identified. However, bacterial coinfection is considered relatively infrequent in hospitalized patients with COVID-19, and the co-prevalence of Streptococcus pneumoniae is low.Material/MethodsWe retrospectively analyzed the clinical characteristics and outcomes of patients subsequently admitted to AMITA Health Saint Francis Hospital between March 1 and June 30, 2020, with documented SARS-CoV-2 and S. pneumoniae coinfection.ResultsWe identified 11 patients with S. pneumoniae coinfection. The median age was 77 years (interquartile range [IQR], 74–82 years), 45.5% (5/11) were males, 54.5% (6/11) were white, and 90.9% (10/11) were long-term care facility (LTCF) residents. The median length of stay was 7 days (IQR, 6–8 days). Among 11 patients, 4 were discharged in stable condition and 7 had died, resulting in an inpatient mortality rate of 64%.ConclusionsAt our center, 11 patients with COVID-19 pneumonia who had confirmed infection with SARS-CoV-2 were diagnosed with Streptococcus pneumoniae infection while in hospital. All patients had pneumonia confirmed on imaging and a nonspecific increase in markers of inflammation. The in-hospital mortality rate of 64% (7 patients) was higher in this group than in previous reports. This study highlights the importance of monitoring bacterial coinfection in patients with viral lung infection due to SARS-CoV-2.

Tuberculosis and COVID-19: Lessons from the Past Viral Outbreaks and Possible Future Outcomes.

Background The threat of contagious infectious diseases is constantly evolving as demographic explosion, travel globalization, and changes in human lifestyle increase the risk of spreading pathogens, leading to accelerated changes in disease landscape. Of particular interest is the aftermath of superimposing viral epidemics (especially SARS-CoV-2) over long-standing diseases, such as tuberculosis (TB), which remains a significant disease for public health worldwide and especially in emerging economies. Methods and Results The PubMed electronic database was systematically searched for relevant articles linking TB, influenza, and SARS-CoV viruses and subsequently assessed eligibility according to inclusion criteria. Using a data mining approach, we also queried the COVID-19 Open Research Dataset (CORD-19). We aimed to answer the following questions: What can be learned from other coronavirus outbreaks (focusing on TB patients)? Is coinfection (TB and SARS-CoV-2) more severe? Is there a vaccine for SARS-CoV-2? How does the TB vaccine affect COVID-19? How does one diagnosis affect the other? Discussions. Few essential elements about TB and SARS-CoV coinfections were discussed. First, lessons from past outbreaks (other coronaviruses) and influenza pandemic/seasonal outbreaks have taught the importance of infection control to avoid the severe impact on TB patients. Second, although challenging due to data scarcity, investigating the pathological pathways linking TB and SARS-CoV-2 leads to the idea that their coexistence might yield a more severe clinical evolution. Finally, we addressed the issues of vaccination and diagnostic reliability in the context of coinfection. Conclusions Because viral respiratory infections and TB impede the host's immune responses, it can be assumed that their lethal synergism may contribute to more severe clinical evolution. Despite the rapidly growing number of cases, the data needed to predict the impact of the COVID-19 pandemic on patients with latent TB and TB sequelae still lies ahead. The trial is registered with NCT04327206, NCT01829490, and NCT04121494.

First report of the lethal activity and synergism between deltamethrin, amitraz and piperonyl butoxide against susceptible and pyrethroid-resistant nymphs of Triatoma infestans

In South America, Triatoma infestans (Hemiptera: Reduviidae) is the main vector of the parasite Trypanosoma cruzi, etiological agent of Chagas disease. The main strategy for vector control is to spray domestic structures with pyrethroids. Reports of populations of T. infestans with varying degrees of resistance to pyrethroids have made the search for alternative molecules for vector control necessary. In the first stage of this work we investigated the lethal activity of amitraz and deltamethrin against susceptible and pyrethroid-resistant nymphs of Triatoma infestans. Lethal dose at 50% (LD50) of susceptible nymphs were compared with those recorded in pyrethroid-resistant nymphs and the resistance ratio (RR50) was obtained. The RR50 of deltamethrin was approximately 300. In the case of amitraz, we observed similar triatomicidal activity in the two nymph populations (RR50: 0.7). In a second stage of the work, we determined the synergistic effect of amitraz and piperonyl butoxide (PBO) on the lethal activity of deltamethrin. The strong synergistic effect of PBO on the lethal activity of deltamethrin in resistant nymphs produced a decrease in RR50 to almost one third of the RR50 reported in absence of the synergist. Amitraz plus PBO lethal activity was similarly increased in pyrethroid susceptible and resistant nymphs. Our data indicate that deltamethrin synergism by amitraz was higher against resistant than to susceptible nymphs (Synergist ratio (SR50) of: 7.2- and 4.1-fold, respectively). In pyrethroid resistant nymphs, the highest level of synergism was obtained combining deltamethrin with amitraz and PBO (SR50: 26.7-fold). These results indicate that this combination could be considered an effective alternative for the control of T. infestans.

Metagenomic Characterization of Influenza Virus: Bacteria Super-Infections Associated With Death and Survival

Abstract Bacterial super-infections (BSIs) increase morbidity and mortality during influenza epidemics and pandemics, but not all strains of influenza virus uniformly increase host susceptibility to BSIs. Infection of mice with a swine virus isolate, A/swine/Texas/4199-2/98-H3N2 (TX98), did not significantly predispose the host to BSI mortality regardless of whether the BSI was caused by S aureus, S pneumoniae, or S pyogenes. Comparison of this survival phenotype with the laboratory influenza virus strain A/Puerto Rico/3/1934-H1N1, which demonstrates lethal synergism, showed that cellular recruitment profiles and cytokine responses differ between the two viruses in a manner that implicates host responses against the invading virus as a contributor to secondary infection severity. To better understand host, viral, and bacterial responses underlying disparate outcomes, we utilized metagenomic analysis of 559 genes, the NanoString nCounter Immunology Panel-Plus kit and FFPE mouse lungs from a published BSI time course. Results show an overall increased level of gene expression during BSIs associated with survival when compared to peak viral titers. Early viral clearance and the presence of S pyogenes in the lungs of TX98-infected lungs 24 hours after BSI was confirmed. Host responses tied to differences in early viral detection and clearance consisted of RIG-I, OAS, TLR3, TLR8, and TLR9. Key changes were noted in the expression of type I and II interferons, complement proteins, cytokines, chemokines, Fc receptors, scavenger receptors, the immunoproteasome, and genes associated with T, B, Treg, and NK cell activation. Interestingly, there was no significant increase in host antimicrobial peptides during BSIs associated with survival while CAMP and Nos2 were significantly increased 24 hours prior to death in lethal BSIs. To our knowledge, this is the first side-by-side metagenomics study of influenza BSIs associated with death and survival. Results offer mechanistic insight into clinical outcomes.

Community-acquired bacterial co-infection predicts severity and mortality in influenza-associated pneumonia admitted patients.

Influenza is frequently complicated by bacterial co-infection, causing additional hospitalization and mortality. We determined the incidence, risk factors and outcomes of patients with influenza-associated community-acquired bacterial co-infection. This was a retrospective, observational study. Influenza was diagnosed using the polymerase chain reaction. Co-infection had to be confirmed using standard bacteriological tests. The primary endpoint was presence of community-acquired co-infection, and the secondary endpoint was in-hospital mortality. During the 8 influenza seasons from 2010 to 2018, of the 209 influenza-associated pneumonia admitted patients, 41 (19.6%) were identified with community-acquired bacterial co-infections and Staphylococcus aureus was the predominant strain. Compared with patients without co-infection, patients with co-infection had similar demographic characteristics and co-morbidities, obtained a higher APACHE II score and a higher SOFA score, and had higher ratio of sepsis shock, invasive mechanical ventilation, and ICU requirement. In-hospital mortality independently associated with bacterial co-infection (adjusted hazard ratio (aHR) 2.619; 95%CI 1.252-5.480; p=0.011); in subgroup S.aureus (aHR 6.267; 95%CI 2.679-14.662; p<0.001) and other pathogens (aHR 2.964; 95%CI 1.160-7.577; p=0.023); and in subgroup positive findings in bloodstream (aHR 7.420; 95%CI 2.712-20.302; p<0.001) and positive findings in other site (aHR 3.427; 95%CI 1.514-7.757; p=0.003). Community-acquired bacterial co-infection was frequent in influenza-associated pneumonia, without risk factor identified yet. Bacterial co-infection was likely to predict severity, and was an independent risk factor for in-hospital mortality. Co-infection of Staphylococcus aureus with influenza was identified as a lethal synergism, and should be targeted when developing clinical antibiotic strategies.

Discovery and Characterization of Diazenylaryl Sulfonic Acids as Inhibitors of Viral and Bacterial Neuraminidases.

Viral neuraminidases are an established drug target to combat influenza. Severe complications observed in influenza patients are primarily caused by secondary infections with e.g., Streptococcus pneumoniae. These bacteria engage in a lethal synergism with influenza A viruses (IAVs) and also express neuraminidases. Therefore, inhibitors with dual activity on viral and bacterial neuraminidases are expected to be advantageous for the treatment of influenza infections. Here we report on the discovery and characterization of diazenylaryl sulfonic acids as dual inhibitors of viral and Streptococcus pneumoniae neuraminidase. The initial hit came from a virtual screening campaign for inhibitors of viral neuraminidases. For the most active compound, 7-[2-[4-[2-[4-[2-(2-hydroxy-3,6-disulfo-1-naphthalenyl)diazenyl]-2-methylphenyl]diazenyl]-2-methylphenyl]diazenyl]-1,3-naphthalenedisulfonic acid (NSC65847; 1), the Ki-values measured in a fluorescence-based assay were lower than 1.5 μM for both viral and pneumococcal neuraminidases. The compound also inhibited N1 virus variants containing neuraminidase inhibitor resistance-conferring substitutions. Via enzyme kinetics and nonlinear regression modeling, 1 was suggested to impair the viral neuraminidases and pneumococcal neuraminidase with a mixed-type inhibition mode. Given its antiviral and antipneumococcal activity, 1 was identified as a starting point for the development of novel, dual-acting anti-infectives.

Mitogen-activated protein kinases (MAPKs) regulate IL-6 over-production during concomitant influenza virus and Staphylococcus aureus infection

Bacterial super-infections are a major complication of influenza virus (IV) infections and often lead to severe pneumonia. One hallmark of IV-associated Staphylococcus aureus (S. aureus) infection is rapid progression to a serious disease outcome. Changes in immune and inflammatory host responses increase morbidity and complicate efficient therapy. A key player during inflammation is the multifunctional cytokine IL-6. Although increased IL-6 levels have been observed after severe disease upon IV and/or bacterial super-infection, the underlying molecular mechanisms still remain to be elucidated. In the present study, we focused on cellular signalling pathways regulating IL-6 production upon IV/S. aureus super-infection. Additionally, infection with viable bacteria was mimicked by lipoteichoic acid stimulation in this model. Analyses of cellular signalling mechanisms revealed synergistically increased activation of the MAPK p38 as well as enhanced phosphorylation of the MAPKs ERK1/2 and JNK in the presence of super-infecting bacteria. Interestingly, inhibition of MAPK activity indicated a strong dependence of IL-6 expression on p38 and ERK1/2, while the MAPK JNK seems not to be involved. Thus, our results provide new molecular insights into the regulation of IL-6, a marker of severe disease, which might contribute to the lethal synergism of IV and S. aureus.

Dual Function of Gold Nanoparticles in Synergism with Mitoxantrone and Microwave Hyperthermia Against Melanoma Cells

Background:This study was performed to evaluate any synergetic effects of mitoxantrone (MX) and gold nanoparticles (GNPs) as dual therapeutic approach, along with microwave (MW) hyperthermia for melanoma cancer.Methods:Various tests were performed on the DFW melanoma cell line in the presence of MX and different concentrations of GNPs, with and without MW irradiation. MTT [3-(4,5-dimethylthiazol–2-yl)-2,5-iphenyltetrazolium bromide] assays were conducted to evaluate the effectiveness of the used therapeutic methods in terms of cell survival. Relative lethal synergism (RLS) was calculated as the ratio of cell death following hyperthermia in the presence of a treatment agent to that after applying hyperthermia in the absence of the same treatment agent.Results:Results showed MX and GNPs under MW irradiation to provide maximum cell death (P < 0.001 compared to the other groups). The mean RLS for MW hyperthermia along with the MX-GNP combination was 4.14, whereas in the absence of GNP the value for MX chemotherapy was 0.94.Conclusion:MX chemotherapy in the presence of different concentrations of GNP did not alter cell survival as compared to in its absence.

Killing two birds with one stone – Prenylated flavonoids disrupt the lethal synergism of influenza A viruses and pneumococci

Killing two birds with one stone – Prenylated flavonoids disrupt the lethal synergism of influenza A viruses and pneumococci

Discovery of prenylated flavonoids with dual activity against influenza virus and Streptococcus pneumoniae.

Influenza virus neuraminidase (NA) is the primary target for influenza therapeutics. Severe complications are often related to secondary pneumonia caused by Streptococcus pneumoniae (pneumococci), which also express NAs. Recently, a NA-mediated lethal synergism between influenza A viruses and pneumococci was described. Therefore, dual inhibitors of both viral and bacterial NAs are expected to be advantageous for the treatment of influenza. We investigated the traditional Chinese herbal drug sāng bái pí (mulberry root bark) as source for anti-infectives. Two prenylated flavonoid derivatives, sanggenon G (4) and sanggenol A (5) inhibited influenza A viral and pneumococcal NAs and, in contrast to the approved NA inhibitor oseltamivir, also planktonic growth and biofilm formation of pneumococci. Evaluation of 27 congeners of 5 revealed a correlation between the degree of prenylation and bioactivity. Abyssinone-V 4′-methyl ether (27) inhibited pneumococcal NA with IC50 = 2.18 μM, pneumococcal growth with MIC = 5.63 μM, and biofilm formation with MBIC = 4.21 μM, without harming lung epithelial cells. Compounds 5 and 27 also disrupt the synergism between influenza A virus and pneumococcal NA in vitro, hence functioning as dual-acting anti-infectives. The results warrant further studies on whether the observed disruption of this synergism is transferable to in vivo systems.

Influenza A virus-induced release of interleukin-10 inhibits the anti-microbial activities of invariant natural killer T cells during invasive pneumococcal superinfection.

During influenza A virus (IAV) infection, changes in the lung's physical and immunological defenses predispose the host to bacterial superinfections. Invariant natural killer T (iNKT) cells are innate-like T lymphocytes that have beneficial or harmful functions during infection. We investigated the iNKT cells' role in a model of invasive pneumococcal superinfection. The use of Jα18-/- mice indicated that iNKT cells limited susceptibility to influenza-pneumococcal infection and reduced the lethal synergism. This role did not depend on immune-based anti-bacterial mechanisms. At the time of bacterial exposure, iNKT cells from IAV-experienced mice failed to produce antipneumococcal interferon-γ and adoptive transfer of fresh iNKT cells before Streptococcus pneumoniae challenge did not restore anti-bacterial host defenses. Impaired iNKT cell activation in superinfected animals was related to the IAV-induced immunosuppressive cytokine interleukin-10 (IL-10), rather than to an intrinsic functional defect. IL-10 dampened the activation of iNKT cells in response to pneumococci by inhibiting the production of IL-12 by pulmonary monocyte-derived dendritic cells. Neutralization of IL-10 restored iNKT cell activation and tends to increase resistance to secondary bacterial infection. Overall, iNKT cells have a beneficial role (upstream of bacterial colonization) in controlling influenza-pneumococcal superinfection, although they represent novel targets of immunosuppression at the time of bacterial challenge.

Dual Acting Neuraminidase Inhibitors Open New Opportunities to Disrupt the Lethal Synergism between Streptococcus pneumoniae and Influenza Virus.

Secondary infections with Streptococcus pneumoniae cause severe pneumonia and enhance lethality during influenza epidemics and pandemics. Structural and functional similarities with viral neuraminidase (NA) suggest that the highly prevalent pneumococcal NAs, NanA and NanB, might contribute to this lethal synergism by supporting viral replication and that dual acting NA inhibitors (NAIs) will disrupt it. To verify this hypothesis, NanA and NanB were expressed in E. coli. After confirming their activity in enzyme assays, in vitro models with influenza virus A/Jena/8178/09 (Jena/8178) and the recombinant NanA or NanB (rNanA and rNanB) were established in A549 and MDCK cells to mimic the role of these pneumococcal NAs during co-infection. Studies on the influence of both NAs on viral receptor expression, spread, and yield revealed a distinct effect of NanA and NanB on viral replication in these in vitro models. Both enzymes were able to support Jena/8178 replication at certain concentrations. This synergism was disrupted by the NAIs oseltamivir, DANA, katsumadain A, and artocarpin exerting an inhibitory effect on viral NA and NanA. Interestingly, katsumadain A and artocarpin inhibited rNanA and rNanB similarly. Zanamivir did not show activity. These results demonstrate a key role of pneumococcal NAs in the lethal synergism with influenza viruses and reveal opportunities for its effective disruption.

Synthetic predator cues impair immune function and make the biological pesticide Bti more lethal for vector mosquitoes.

The control of vector mosquitoes is one of the biggest challenges facing humankind with the use of chemical pesticides often leading to environmental impact and the evolution of resistance. Although to a lesser extent, this also holds for Bacillus thuringiensis israelensis (Bti), the most widely used biological pesticide to control mosquito populations. This raises the need for the development of integrated pest management strategies that allow the reduction of Bti concentrations without loss of the mosquito control efficiency. To this end, we tested in a laboratory experiment the combined effects of larval exposure to a sublethal Bti concentration and predation risk cues on life history and physiology of larval and adult Culex pipiens mosquitoes. Besides natural predator kairomones and prey alarm cues, we also tested synthetic kairomones of Notonecta predators. Neither Bti nor predation risk cues affected mortality, yet when both stressors were combined mortality increased on average by 133% compared to the treatment with only predation risk cues. This synergistic interaction was also present when Bti was combined with synthetic kairomones. This was further reflected in changes of the composite index of population performance, which suggested lowered per capita growth rates in mosquitoes exposed to Bti but only when Bti was combined with synthetic kairomones. Furthermore, predation risk cues shortened larval development time, reduced mass at metamorphosis in males, and had an immunosuppressive effect in larval and adult mosquitoes which may affect the mosquito vector competence. We provide the first demonstration that synthetic kairomones may generate similar effects on prey as natural kairomones. The identified immunosuppressive effect of synthetic kairomones and the novel lethal synergism type between a biological pesticide and synthetic predator kairomones provide an important proof of principle illustrating the potential of this combination for integrated mosquito control and should in a next step be evaluated under more natural conditions. It may guide novel integrated pest management programs with Bti that incorporate synthetic kairomones and thereby can reduce environmental impact and evolution of resistance creating more efficient and sustainable mosquito control.

Lethal Synergism between Influenza and Streptococcus pneumoniae.

The devastating synergism of bacterial pneumonia with influenza viral infections left its mark on the world over the last century. Although the details of pathogenesis remain unclear, the synergism is related to a variety of factors including pulmonary epithelial barrier damage which exposes receptors that influence bacterial adherence and the triggering of an exaggerated innate immune response and cytokine storm, which further acts to worsen the injury. Several therapeutics and combination therapies of antibiotics, anti-inflammatories including corticosteroids and toll-like receptor modifiers, and anti-virals are being discussed. This mini review summarizes recent developments in unearthing the pathogenesis of the lethal synergism of pneumococcal co-infection following influenza, as well as addresses potential therapeutic options and combinations of therapies currently being evaluated.

Synthetic predator cues impair immune function and make the biological pesticideBtimore lethal for vector mosquitoes

The control of vector mosquitoes is one of the biggest challenges facing humankind with the use of chemical pesticides often leading to environmental impact and the evolution of resistance. Although to a lesser extent, this also holds for Bacillus thuringiensis israelensis (Bti), the most widely used biological pesticide to control mosquito populations. This raises the need for the development of integrated pest management strategies that allow the reduction of Bti concentrations without loss of the mosquito control efficiency. To this end, we tested in a laboratory experiment the combined effects of larval exposure to a sublethal Bti concentration and predation risk cues on life history and physiology of larval and adult Culex pipiens mosquitoes. Besides natural predator kairomones and prey alarm cues, we also tested synthetic kairomones of Notonecta predators. Neither Bti nor predation risk cues affected mortality, yet when both stressors were combined mortality increased on average by 133% compared to the treatment with only predation risk cues. This synergistic interaction was also present when Bti was combined with synthetic kairomones. This was further reflected in changes of the composite index of population performance, which suggested lowered per capita growth rates in mosquitoes exposed to Bti but only when Bti was combined with synthetic kairomones. Furthermore, predation risk cues shortened larval development time, reduced mass at metamorphosis in males, and had an immunosuppressive effect in larval and adult mosquitoes which may affect the mosquito vector competence. We provide the first demonstration that synthetic kairomones may generate similar effects on prey as natural kairomones. The identified immunosuppressive effect of synthetic kairomones and the novel lethal synergism type between a biological pesticide and synthetic predator kairomones provide an important proof of principle illustrating the potential of this combination for integrated mosquito control and should in a next step be evaluated under more natural conditions. It may guide novel integrated pest management programs with Bti that incorporate synthetic kairomones and thereby can reduce environmental impact and evolution of resistance creating more efficient and sustainable mosquito control.

Phosphoproteomics of MAPK inhibition in BRAF-mutated cells and a role for the lethal synergism of dual BRAF and CK2 inhibition.

Activating mutations in the MAPK pathway are prevalent drivers of several cancers. The chief consequence of these mutations is a hyperactive ERK1/2 MAPK able to promote cell proliferation, producing a critical hallmark of metastatic disease. The biochemistry of the ERK pathway is well characterized; however, how the pathway achieves different outcomes in the face of genetic aberrations of cancer and subsequent treatment with chemical inhibitors is not clear. To investigate this, we used mass spectrometry to complete a global phosphoproteomic analysis of a BRAFV600E thyroid cancer cell line (SW1736) after treatment with the mutation-selective inhibitor vemurafenib (PLX4032) and MEK1/2 inhibitor selumetinib (AZD6244). We identified thousands of phosphorylation events orchestrated in BRAFV600E cells and performed kinase landscape analysis to identify putative kinases regulated in response to MAPK blockade. The abundance of phosphopeptides containing consensus motifs for acidophilic kinases increased after short-term inhibition with these compounds. We showed that coinhibition of the pleiotropic acidophilic protein kinase CK2 (CK2) and BRAFV600E synergistically reduced proliferation in patient-derived melanomas and thyroid cancer cells harboring the BRAF lesion. We investigated this mechanism and show a role for CK2 in controlling AKT activation that was not reliant on changes to PTEN or PDK1 phosphorylation. These findings highlight a role for CK2 blockade in potentiating the antiproliferative effects of BRAF and MEK inhibition in BRAF cancers.