Crosstalk Between Staphylococcus aureus and Innate Immunity: Focus on Immunometabolism

Staphylococcus aureus is a leading cause of bacterial infections globally in both healthcare and community settings. The success of this bacterium is the product of an expansive repertoire of virulence factors in combination with acquired antibiotic resistance and propensity for biofilm formation. S. aureus leverages these factors to adapt to and subvert the host immune response. With the burgeoning field of immunometabolism, it has become clear that the metabolic program of leukocytes dictates their inflammatory status and overall effectiveness in clearing an infection. The metabolic flexibility of S. aureus offers an inherent means by which the pathogen could manipulate the infection milieu to promote its survival. The exact metabolic pathways that S. aureus influences in leukocytes are not entirely understood, and more work is needed to understand how S. aureus co-opts leukocyte metabolism to gain an advantage. In this review, we discuss the current knowledge concerning how metabolic biases dictate the pro- vs. anti-inflammatory attributes of various innate immune populations, how S. aureus metabolism influences leukocyte activation, and compare this with other bacterial pathogens. A better understanding of the metabolic crosstalk between S. aureus and leukocytes may unveil novel therapeutic strategies to combat these devastating infections

Structure of the 5′ Untranslated Region of Enteroviral Genomic RNA

Enteroviral RNA genomes share a long, highly structured 5= untranslated region (5= UTR) containing a type I internal ribosome entry site (IRES). The 5= UTR is composed of stably folded RNA domains connected by unstructured RNA regions. Proper folding and functioning of the 5= UTR underlies the efficiency of viral replication and also determines viral virulence. We have characterized the structure of 5= UTR genomic RNA from coxsackievirus B3 using selective 2=-hydroxyl acylation analyzed by primer extension (SHAPE) and base-specific chemical probes in solution. Our results revealed novel structural features, including realignment of major domains, newly identified long-range interactions, and an intrinsically disordered connecting region. Together, these newly identified features contribute to a model for enteroviral 5= UTRs with type I IRES elements that links structure to function during the hierarchical processes directed by genomic RNA during viral infection. IMPORTANCE: Enterovirus infections are responsible for human diseases, including myocarditis, pancreatitis, acute flaccid paralysis, and poliomyelitis. The virulence of these viruses depends on efficient recognition of the RNA genome by a large family of host proteins and protein synthesis factors, which in turn relies on the threedimensional folding of the first 750 nucleotides of the molecule. Structural information about this region of the genome, called the 5= untranslated region (5= UTR), is needed to assist in the process of vaccine and antiviral development. This work presents a model for the structure of the enteroviral 5= UTR. The model includes an RNA element called an intrinsically disordered RNA region (IDRR). Intrinsically disordered proteins (IDPs) are well known, but correlates in RNA have not been proposed. The proposed IDRR is a 20-nucleotide region, long known for its functional importance, where structural flexibility helps explain recognition by factors controlling multiple functional states

Molecular pathways elicited by Toll-like receptor 2 (TLR2) signaling during Staphylococcus aureus craniotomy infection

A craniotomy is required to access the brain during neurosurgery for tumor resection or epilepsy treatment and despite extensive precautionary measures, infectious complications occur at a frequency of 1-3% (1-3). Approximately half of craniotomy infections are caused by S. aureus, which forms a biofilm on the bone flap. Our laboratory has developed a mouse model of S. aureus craniotomy-associated biofilm infection that shares important ultrastructural and MRI attributes with human disease (4). Toll-like receptor 2 (TLR2) is expressed by cells of the innate immune system and is critical for recognizing pathogen-associated molecular patterns (PAMPs) in the cell wall of gram-positive bacteria, such as S. aureus. Recent studies have shown that TLR2 is critical for S. aureus containment during craniotomy infection, in that TLR2 knockout (KO) mice displayed increased bacterial burden in the brain, galea, and bone flap during acute and chronic infection (days 3 and 14, respectively)(5). Cytokine and chemokine expression was dramatically reduced in TLR2 KO mice which did not coincide with a decrease in leukocyte infiltrates in the brain or galea. This suggested that S. aureus outgrowth in the context of TLR2 deficiency is not the result of altered leukocyte recruitment, but instead due to defects in their activation status. To determine this, RNA-sequencing (RNA-seq) was performed on microglia purified from the brain of WT and TLR2 KO mice at either day 3 or 7 post-infection by FACS with the goal of identifying microglial transcripts that are divergent between the two mouse strains (either increased or decreased). RNA-seq revealed Fibroblast Growth Factor Receptor (FGFR) 2 and 3 were upregulated in TLR2 KO microglia. This suggests a direct correlation between TLR2, FGFR2 and FGFR3. Since TLR2 KO animals have a bias toward an anti-inflammatory response to infection and the fact that FGFR2 and FGFR3 are upregulated during wound healing or infection, this could be a reason why higher levels are observed in TLR2 KO microglia. FGRF2 and FGRF3 are key regulators of neuronal protection and repair following brain injury/infection. Therefore, microglia may be increasing the expression of these receptors in an effort to control the damage that is occurring in response to the increased bacterial burden in TLR2 KO animals.https://digitalcommons.unmc.edu/surp2020/1000/thumbnail.jp

Mapping Lesion-Related Epilepsy to a Human Brain Network

Importance: It remains unclear why lesions in some locations cause epilepsy while others do not. Identifying the brain regions or networks associated with epilepsy by mapping these lesions could inform prognosis and guide interventions. Objective: To assess whether lesion locations associated with epilepsy map to specific brain regions and networks. Design, setting, and participants: This case-control study used lesion location and lesion network mapping to identify the brain regions and networks associated with epilepsy in a discovery data set of patients with poststroke epilepsy and control patients with stroke. Patients with stroke lesions and epilepsy (n = 76) or no epilepsy (n = 625) were included. Generalizability to other lesion types was assessed using 4 independent cohorts as validation data sets. The total numbers of patients across all datasets (both discovery and validation datasets) were 347 with epilepsy and 1126 without. Therapeutic relevance was assessed using deep brain stimulation sites that improve seizure control. Data were analyzed from September 2018 through December 2022. All shared patient data were analyzed and included; no patients were excluded. Main outcomes and measures: Epilepsy or no epilepsy. Results: Lesion locations from 76 patients with poststroke epilepsy (39 [51%] male; mean [SD] age, 61.0 [14.6] years; mean [SD] follow-up, 6.7 [2.0] years) and 625 control patients with stroke (366 [59%] male; mean [SD] age, 62.0 [14.1] years; follow-up range, 3-12 months) were included in the discovery data set. Lesions associated with epilepsy occurred in multiple heterogenous locations spanning different lobes and vascular territories. However, these same lesion locations were part of a specific brain network defined by functional connectivity to the basal ganglia and cerebellum. Findings were validated in 4 independent cohorts including 772 patients with brain lesions (271 [35%] with epilepsy; 515 [67%] male; median [IQR] age, 60 [50-70] years; follow-up range, 3-35 years). Lesion connectivity to this brain network was associated with increased risk of epilepsy after stroke (odds ratio [OR], 2.82; 95% CI, 2.02-4.10; P \u3c .001) and across different lesion types (OR, 2.85; 95% CI, 2.23-3.69; P \u3c .001). Deep brain stimulation site connectivity to this same network was associated with improved seizure control (r, 0.63; P \u3c .001) in 30 patients with drug-resistant epilepsy (21 [70%] male; median [IQR] age, 39 [32-46] years; median [IQR] follow-up, 24 [16-30] months). Conclusions and relevance: The findings in this study indicate that lesion-related epilepsy mapped to a human brain network, which could help identify patients at risk of epilepsy after a brain lesion and guide brain stimulation therapies

Hematopoietic Cell Transplant and Use of Massage for Improved Symptom Management: Results from a Pilot Randomized Control Trial

Background. Pediatric hematopoietic cell transplant (HCT) is a lifesaving treatment that often results in physical and psychological discomfort. An acupressure-massage intervention may improve symptom management in this setting. Methods. This randomized controlled pilot trial compared a combined massage-acupressure intervention to usual care. Children were offered three practitioner-provided sessions per week throughout hospitalization. Parents were trained to provide additional acupressure as needed. Symptoms were assessed using nurses' reports and two questionnaires, the behavioral affective and somatic experiences scale and the Peds quality of life cancer module. Results. We enrolled 23 children, ages 5 to 18. Children receiving the intervention reported fewer days of mucositis (Hedges' g effect size ES = 0.63), lower overall symptom burden (ES = 0.26), feeling less tired and run-down (ES = 0.86), having fewer moderate/severe symptoms of pain, nausea, and fatigue (ES = 0.62), and less pain (ES = 0.42). The intervention group showed trends toward increasing contentness/serenity (ES = +0.50) and decreasing depression (ES = −0.45), but not decreased anxiety (ES = +0.42). Differences were not statistically significant. Discussion. Feasibility of studying massage-acupressure was established in children undergoing HCT. Larger studies are needed to test the efficacy of such interventions in reducing HCT-associated symptoms in children

Exploring the measurement of markedness and its relationship with other linguistic variables

Antonym pair members can be differentiated by each word's markedness-that distinction attributable to the presence or absence of features at morphological or semantic levels. Morphologically marked words incorporate their unmarked counterpart with additional morphs (e.g., "unlucky" vs. "lucky"); properties used to determine semantically marked words (e.g., "short" vs. "long") are less clearly defined. Despite extensive theoretical scrutiny, the lexical properties of markedness have received scant empirical study. The current paper employs an antonym sequencing approach to measure markedness: establishing markedness probabilities for individual words and evaluating their relationship with other lexical properties (e.g., length, frequency, valence). Regression analyses reveal that markedness probability is, as predicted, related to affixation and also strongly related to valence. Our results support the suggestion that antonym sequence is reflected in discourse, and further analysis demonstrates that markedness probabilities, derived from the antonym sequencing task, reflect the ordering of antonyms within natural language. In line with the Pollyanna Hypothesis, we argue that markedness is closely related to valence; language users demonstrate a tendency to present words evaluated positively ahead of those evaluated negatively if given the choice. Future research should consider the relationship of markedness and valence, and the influence of contextual information in determining which member of an antonym pair is marked or unmarked within discourse