Legionella pneumophila Is Directly Sensitive to 2-Deoxyglucose-Phosphate via Its UhpC Transporter but Is Indifferent to Shifts in Host Cell Glycolytic Metabolism.

Toll-like receptor (TLR) stimulation induces a pronounced shift to increased glycolytic metabolism in mammalian macrophages. We observed that bone marrow-derived macrophages (BMMs) increase glycolysis in response to infection with Legionella pneumophila, but the role of host macrophage glycolysis in terms of intracellular L. pneumophila replication is not currently understood. Treatment with 2-deoxyglucose (2DG) blocks L. pneumophila replication in mammalian macrophages but has no effect on bacteria grown in broth. In addition, we found that 2DG had no effect on bacteria grown in amoebae. We used a serial enrichment strategy to reveal that the effect of 2DG on L. pneumophila in macrophages requires the L. pneumophila hexose-phosphate transporter UhpC. Experiments with UhpC-deficient L. pneumophila revealed that mutant bacteria are also resistant to growth inhibition following treatment with phosphorylated 2DG in broth, suggesting that the inhibitory effect of 2DG on L. pneumophila in mammalian cells requires 2DG phosphorylation. UhpC-deficient L. pneumophila replicates without a growth defect in BMMs and protozoan host cells and also replicates without a growth defect in BMMs treated with 2DG. Our data indicate that neither TLR signaling-dependent increased macrophage glycolysis nor inhibition of macrophage glycolysis has a substantial effect on intracellular L. pneumophila replication. These results are consistent with the view that L. pneumophila can employ diverse metabolic strategies to exploit its host cells.IMPORTANCE We explored the relationship between macrophage glycolysis and replication of an intracellular bacterial pathogen, Legionella pneumophila Previous studies demonstrated that a glycolysis inhibitor, 2-deoxyglucose (2DG), blocks replication of L. pneumophila during infection of macrophages, leading to speculation that L. pneumophila may exploit macrophage glycolysis. We isolated L. pneumophila mutants resistant to the inhibitory effect of 2DG in macrophages, identifying a L. pneumophila hexose-phosphate transporter, UhpC, that is required for bacterial sensitivity to 2DG during infection. Our results reveal how a bacterial transporter mediates the direct antimicrobial effect of a toxic metabolite. Moreover, our results indicate that neither induction nor impairment of host glycolysis inhibits intracellular replication of L. pneumophila, which is consistent with a view of L. pneumophila as a metabolic generalist.

Assessing the Potential for Oligomer Formation from the Reactions of Lactones in Secondary Organic Aerosols.

Laboratory and field measurements have demonstrated that 2-methyl glyceric acid (2-MG) is the base component of a wide range of chemical species found in methacrolein-derived secondary organic aerosol (SOA). In order to explore the recently proposed hypothesis that a lactone oxidation intermediate is the origin of 2-MG and its derivatives in SOA, nuclear magnetic resonance techniques were used to study kinetics and reaction products of the aqueous phase reactions of a model lactone, ß-propiolactone (BPL). BPL was found to react with a lifetime of 4-10 h (depending on solution conditions) via a general acid catalyzed mechanism, which suggests that lactones similar to BPL are reactive on an atmospherically relevant time scale. BPL was also shown to form a variety of nucleophilic addition products (organosulfates and nitrates and oligomers) similar to the 2-MG-based species observed in previous experiments involving the photooxidation and SOA processing of methacrolein. While many of the BPL reaction products could be rationalized via an epoxide-like nucleophilic addition mechanism, evidence for ester-like nucleophilic addition was suggested through the observation of inorganic ion-catalyzed oligomer formation. The formation of oligomers was found to depend strongly on the proportion of organic acid nucleophile present in its deprotonated form. Therefore, due to the nature of the general acid catalysis and importance of deprotonated acids for efficient BPL oligomerization, it is suggested that oligomerization from lactone intermediates will be more efficient at higher SOA pH values. This result may help explain why overall isoprene-derived SOA formation has been observed to be largely pH-independent. Overall, the results strongly support the previous conclusion that a lactone intermediate is responsible for the formation of 2-MG-related species found in methacrolein-derived SOA.

The devil is in the details: Understanding how misinformation regarding epilepsy manifests in TikTok videos.

OBJECTIVE: This study sought to understand the amount of misinformation surrounding epilepsy on the social media platform, TikTok. METHODS: Videos from TikTok were searched using keyword "epilepsy." In all, 109 videos were categorized as personal experience videos, event videos, or educational videos. Misinformation surrounding each video was analyzed by two independent reviewers. The number of videos and views of each were tracked. RESULTS: Event videos garnered the most attention (80% of total views). Of the event videos, 26/47 contained misinformation in the form of calling a nonepileptic event an epileptic seizure (55%). Videos of nonepileptic events labeled as epileptic seizures amassed 109 956 400 views. SIGNIFICANCE: This novel study quantifies the amount of misinformation regarding epilepsy on the social media platform, TikTok. The results showcase that misinformation is very prevalent on the application. Most of the misinformation consists of the mislabeling of nonepileptic events as epileptic seizures. Physicians should be aware of cardinal features of nonepileptic events to better treat patients. The medical community must understand the type of misinformation people are exposed to in order to educate patients appropriately.

Generation of monocyte-derived tumor-associated macrophages using tumor-conditioned media provides a novel method to study tumor-associated macrophages in vitro.

BACKGROUND: Tumor-associated macrophages (TAM) are expanded and exhibit tumor-promoting properties within the tumor microenvironment. Current methods to study TAM have not been replicated across cancer types and often do not include exogenous growth factors from the tumor, a key factor in TAM differentiation in vivo. METHODS: In this study, an in vitro method to generate monocyte- derived TAM using tumor- conditioned media (TCM) and a cytokine cocktail containing IL-4, IL-10, and M-CSF was utilized to study the phenotype, morphology, and function of TAM across multiple cancer types. TCM was generated from two breast cancer cell lines and an Epstein-Barr virus-positive lymphoma cell line. The properties of in vitro generated TAM were compared to in vitro generated M1 and M2- like macrophages and TAM isolated from patients with cancer. RESULTS: TAM generated in this fashion displayed an increase in CD163/CD206 co-expression compared to M2- like macrophages (87 and 36%, respectively). TAM generated in vitro exhibited increased transcript levels of the functional markers IL-6, IL-10, CCL2, c-Myc, iNOS, and arginase compared to in vitro generated M2-like macrophages. Functionally, in vitro generated TAM inhibited the proliferation of T cells (47% decrease from M1-like macrophages) and the production of IFN-γ by natural killer cells was inhibited (44%) when co-cultured with TAM. Furthermore, in vitro generated TAM secreted soluble factors that promote the growth and survival of tumor cells. CONCLUSIONS: Limited access to patient TAM highlights the need for methods to generate TAM in vitro. Our data confirm that monocyte-derived TAM can be generated reliably using TCM plus the cytokine cocktail of IL-4, IL-10, and M-CSF. Given the ability of TAM to inhibit immune cell function, continued study of methods to deplete or deactivate TAM in the setting of cancer are warranted.