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The 2009 H1N1 pandemic (H1N1pdm) viruses have evolved to contain an E47K substitution in the HA2 subunit of the stalk region of the hemagglutinin (HA) protein. The biological significance of this single amino acid change was investigated by comparing A/California/7/2009 (HA2-E47) with a later strain, A/Brisbane/10/2010 (HA2-K47). The E47K change was found to reduce the threshold pH for membrane fusion from 5.4 to 5.0. An inter-monomer salt bridge between K47 in HA2 and E21 in HA1, a neighboring highly conserved residue, which stabilized the trimer structure, was found to be responsible for the reduced threshold pH for fusion. The higher structural and acid stability of the HA trimer caused by the E47K change also conferred higher viral thermal stability and infectivity in ferrets, suggesting a fitness advantage for the E47K evolutionary change in humans. Our study indicated that the pH of HA fusion activation is an important factor for influenza virus replication and host adaptation. The identification of this genetic signature in the HA stalk region that influences vaccine virus thermal stability also has significant implications for influenza vaccine production.

PD-L1 and VEGF blockade with atezolizumab plus bevacizumab has been shown to improve survival in unresectable hepatocellular carcinoma. TIGIT is an immune checkpoint regulator implicated in many cancers, including unresectable hepatocellular carcinoma. Here, we evaluate the clinical activity and safety of the addition of tiragolumab, an anti-TIGIT monoclonal antibody, to atezolizumab plus bevacizumab. This randomised, open-label, phase 1b–2 umbrella study was conducted at 26 centres across China, France, Israel, New Zealand, South Korea, Taiwan, and the USA. Eligible patients were adults aged 18 years old or older with previously untreated locally advanced unresectable hepatocellular carcinoma, an Eastern Cooperative Oncology Group performance status of 0–1, Child-Pugh class A disease, and a life expectancy of at least 3 months. Eligible patients were randomly assigned (2:1) using permuted block randomisation to receive either tiragolumab 600 mg plus atezolizumab 1200 mg plus bevacizumab 15 mg/kg or atezolizumab 1200 mg plus bevacizumab 15 mg/kg, administered via intravenous infusion every 3 weeks on day 1 of each 21-day cycle. Patients received treatment until unacceptable toxic effects or loss of clinical benefit, whichever occurred first. The primary endpoint was objective response rate. Analysis of clinical activity was done in the efficacy-evaluable population (all patients who received at least one dose of each drug for their assigned treatment regimen) and safety was assessed in all patients who received any study treatment. The trial is registered with ClinicalTrials.gov, NCT04524871, and is ongoing. Between Aug 20, 2020, and Feb 10, 2022, we assessed 154 patients for eligibility and 59 eligible patients were randomly assigned to receive tiragolumab plus atezolizumab plus bevacizumab (n=41) or atezolizumab plus bevacizumab (n=18); one patient in the tiragolumab plus atezolizumab plus bevacizumab group experienced an adverse event before receiving any treatment and withdrew from the study. Median age was 65·0 years (IQR 61·0–73·0). 46 (79%) of 58 patients were male and 12 (21%) were female. Most patients were Asian (23 [40%]) or White (21 [36%]). At the time of clinical cutoff (Aug 21, 2023), median follow-up was 20·6 months (IQR 10·6–28·0) in the tiragolumab plus atezolizumab plus bevacizumab group and 14·0 months (4·2–18·5) in the atezolizumab plus bevacizumab group. The confirmed objective response rate was 43% (95% CI 27–59, n=17) in the tiragolumab plus atezolizumab plus bevacizumab group and 11% (1–35, n=2) in the atezolizumab plus bevacizumab group. All patients in both groups experienced an adverse event. The incidence of pruritis (20 [50%] of 40 patients vs three [17%] of 18 patients), arthralgia (13 [33%] vs two [11%]), and diarrhoea (12 [30%] vs one [6%]) was notably higher in the tiragolumab plus atezolizumab plus bevacizumab group than in the atezolizumab plus bevacizumab group, although these were mainly grade 1–2. The most common grade 3–4 adverse events were hypertension (six [15%] of 40 patients in the tiragolumab plus atezolizumab plus bevacizumab group vs two [11%] of 18 patients in the atezolizumab plus bevacizumab group), aspartate aminotransferase increased (three [8%] of 40 patients vs one [6%] of 18 patients), and proteinuria (two [5%] of 40 patients vs two [11%] of 18 patients). Serious adverse events occurred in 21 (53%) of 40 patients in the tiragolumab plus atezolizumab plus bevacizumab group and in ten (56%) of 18 patients in the atezolizumab plus bevacizumab group. Treatment-related deaths occurred in one patient in the tiragolumab plus atezolizumab plus bevacizumab group (due to cholestasis) and two patients in the atezolizumab plus bevacizumab group (due to oesophageal varices haemorrhage and upper gastrointestinal haemorrhage). The addition of tiragolumab to atezolizumab plus bevacizumab did not appear to result in a substantial worsening of treatment-related or immune-mediated adverse events, and no new safety signals were identified. This signal-seeking study suggests that the addition of tiragolumab to atezolizumab and bevacizumab might be more clinically active than atezolizumab plus bevacizumab alone in unresectable hepatocellular carcinoma. Based on these data, further study of combination tiragolumab plus atezolizumab plus bevacizumab is warranted. F Hoffmann-La Roche and Genentech.

Collective cell movement is critical to the emergent properties of many multicellular systems, including microbial self-organization in biofilms, embryogenesis, wound healing, and cancer metastasis. However, even the best-studied systems lack a complete picture of how diverse physical and chemical cues act upon individual cells to ensure coordinated multicellular behavior. Known for its social developmental cycle, the bacterium Myxococcus xanthus uses coordinated movement to generate three-dimensional aggregates called fruiting bodies. Despite extensive progress in identifying genes controlling fruiting body development, cell behaviors and cell–cell communication mechanisms that mediate aggregation are largely unknown. We developed an approach to examine emergent behaviors that couples fluorescent cell tracking with data-driven models. A unique feature of this approach is the ability to identify cell behaviors affecting the observed aggregation dynamics without full knowledge of the underlying biological mechanisms. The fluorescent cell tracking revealed large deviations in the behavior of individual cells. Our modeling method indicated that decreased cell motility inside the aggregates, a biased walk toward aggregate centroids, and alignment among neighboring cells in a radial direction to the nearest aggregate are behaviors that enhance aggregation dynamics. Our modeling method also revealed that aggregation is generally robust to perturbations in these behaviors and identified possible compensatory mechanisms. The resulting approach of directly combining behavior quantification with data-driven simulations can be applied to more complex systems of collective cell movement without prior knowledge of the cellular machinery and behavioral cues.

•Defective viral genomes enhance the maturation of human dendritic cells.•Their use as immunostimulants improve dendritic cell immunization efficacy.•Defective viral genome naked RNA has strong immunostimulatory activity.•A modified defective viral genome RNA induces strong innate immunity in mice.•This RNA improves the generation of antibodies to a prototypic vaccine in mice. Defective viral genomes (DVGs) are generated during virus replication. DVGs bearing complementary ends are strong inducers of dendritic cell (DC) maturation and of the expression of antiviral and pro-inflammatory cytokines by triggering signaling of the RIG-I family of intracellular pattern recognition receptors. Our data show that DCs stimulated with virus containing DVGs have an enhanced ability to activate human T cells and can induce adaptive immunity in mice. In addition, we describe the generation of a short Sendai virus (SeV)-derived DVG RNA (DVG-324) that maintains strong immunostimulatory activity in vitro and in vivo. DVG-324 induced high levels of Ifnb expression when transfected into cells and triggered fast expression of pro-inflammatory cytokines and mobilization of dendritic cells when injected into the footpad of mice. Importantly, DVG-324 enhanced the production of antibodies to a prototypic vaccine after a single intramuscular immunization in mice. Notably, the pro-inflammatory cytokine profile induced by DVG-324 was different from that induced by poly I:C, the only viral RNA analog currently used as an immunostimulant in vivo, suggesting a distinct mechanism of action. SeV-derived oligonucleotides represent novel alternatives to be harnessed as potent adjuvants for vaccination.

Traumatic brain injury (TBI) is a global source of injury-related death and disability, and survivors often suffer functional and psychiatric consequences that persist for years. Neuroinflammation, mediated in part by microglia, perpetuates chronic dysfunction after TBI and leaves survivors vulnerable to the effects of secondary immune challenges. Previous data from our lab shows that 30 days of mechanical sleep fragmentation (SF) aggravates microglia- associated neuroinflammation in C57BL/6 mice, impairing recovery after TBI. To better understand the mechanisms through which microglia contribute to impairment following post-TBI SF, we used flow cytometry to analyze multiple cell types from brain and peripheral tissues of C57BL/6 mice who received a TBI or sham injury followed by 7 or 30 days of SF or control housing. Next, bulk RNA sequencing was used to analyze gene expression in microglia and coronal slice from the ipsilateral brain. We analyzed differentially expressed genes (DEGs) within each tissue type to determine how ipsilateral brain and microglia are independently influenced by TBI and SF. We also compared microglial DEGS directly to those of coronal slice, gaining novel insight into how microglia contribute to dysfunction in the ipsilateral brain after TBI and post-injury SF. Flow cytometry revealed transient increases in monocyte infiltration to the brain 7 days post-injury (DPI) that resolved by 30 DPI. SF did not exacerbate the immune response to injury within peripheral tissues or the brain at either of these time points. From our transcriptomic analysis, we identified distinct sets of DEGs which are uniquely dysregulated by TBI, SF, and the combination of TBI and SF. Notably, we found distinct subsets of olfactory genes that are differentially dysregulated by TBI and SF in the ipsilateral brain, as well as significant enrichment of cell-cell communication and steroidogenesis pathways that are specifically disrupted in microglia compared to the rest of the brain. Through in-depth transcriptional analysis we identify potential molecular targets that shed light on the mechanisms of TBI-induced microglial activity and reveal how SF after TBI alters this response. Together, these data could inform therapeutic strategies that target neuroinflammation to improve chronic recovery after brain injury.

Oscillations, a highly conserved brain function across mammalian species, play a pivotal role in both brain physiology and pathology. Traumatic brain injury (TBI) frequently results in subacute and chronic alterations in brain oscillations, which are often associated with complications like post-traumatic epilepsy (PTE) in patients and animal models. We recently conducted longitudinal recordings of local field potential from the contralateral hippocampus of 12 strains of recombinant inbred Collaborative Cross (CC) mice and classical laboratory inbred C57BL/6 J mice after lateral fluid percussion injury. In this study, we profiled the acute (<12 h post-injury) and subacute (12–48 h post-injury) hippocampal oscillatory responses to TBI and evaluated their predictive value for PTE. We found dynamic high-amplitude rhythmic spikes with elevated power density and reduced signal complexity that prevailed exclusively during the acute phase in CC031 mice, which later developed PTE. This characteristic early brain oscillatory alteration was absent in CC031 sham controls, as well as in other CC strains and reference C57BL/6 J mice that did not develop PTE after TBI. Our findings offer quantitative measures linking early hippocampal brain oscillation to PTE at a population level in mice. These insights enhance understanding of circuit mechanisms and suggest potential targets for neuromodulatory intervention.

Tef (Eragrostis tef) is an orphan crop that is widely grown in East Africa, primarily in Ethiopia as a staple crop. It is becoming popular in the Western world owing to its nutritious and gluten-free grains and the forage quality of its biomass. Tef is also considered to have a high antioxidant capacity based on cell-free studies. However, the antioxidant activity of tef has never been validated using a physiologically relevant cell model. The purpose of this study was to investigate the antioxidant capacity of tef grain extracts using a mammalian cell model. We hypothesized that the tef grain extracts are capable of modulating the cellular antioxidant response via the modulation of glutathione (GSH) biosynthetic pathways. Therefore, we evaluated the antioxidant activity of purified tef grain extracts in the human acute monocytic leukemia (THP-1) cell line. Our findings revealed that the organic fraction of grain extracts increased the cellular GSH level, which was more evident for brown-colored tef than the ivory variety. Moreover, a brown-tef fraction increased the expressions of GSH-pathway genes, including γ-glutamate cysteine ligase catalytic (GCLC) and modifier (GCLM) subunits and glutathione reductase (GR), an enzyme that plays a key role in GSH biosynthesis, suggesting that tef extracts may modulate GSH metabolism. Several compounds were uniquely identified via mass spectrometry (MS) in GSH-modulating brown-tef samples, including 4-oxo-β-apo-13-carotenone, γ-linolenic acid (methyl ester), 4,4′-(2,3-dimethyl-1,4-butanediyl)bis-phenol (also referred to as 8,8′-lignan-4,4′-diol), and (3β)-3-[[2-[4-(Acetylamino)phenoxy]acetyl]oxy]olean-12-en-28-oic acid. Tef possesses antioxidant activity due to the presence of phytochemicals that can act as direct antioxidants, as well as modulators of antioxidant-response genes, indicating its potential role in alleviating diseases triggered by oxidative stresses. To the best of our knowledge, this is the first report revealing the antioxidant ability of tef extracts in a physiologically relevant human cell model.

Cognitive impairment is a common symptom after traumatic brain injury (TBI). Memory, in particular, is often disrupted during chronic post-injury recovery. To understand the sex-specific effects of brain injury on retrograde and anterograde memory, we examined paired associate learning (PAL), spatial learning and memory, and fear memory after lateral fluid percussion TBI. We hypothesized that male and female mice would display unique memory deficits after TBI. PAL task acquisition was initiated via touchscreen operant conditioning 22 weeks before sham injury or TBI. Post-injury PAL testing occurred 7 weeks post-injury. Barnes maze and fear conditioning were completed at 14- and 15-weeks post-injury, respectively. Contrary to our expectations, behavioral outcomes were not primarily influenced by TBI. Instead, sex-specific differences were observed in all tasks which exposed task-specific trends in male TBI mice. Male mice took longer to complete the PAL task, but this was not affected by TBI and did not compromise the ability to make a correct choice. Latency to reach the goal box decreased across testing days in Barnes maze, but male TBI mice lagged in improvement compared to all other groups. Use of two learning indices revealed that male TBI mice were deficient in transferring information from one day to the next. Finally, acquisition and contextual retention of fear memory were similar between all groups. Cued retention of the tone-shock pairing was influenced by both injury and sex. Male sham mice displayed the strongest cued retention of fear memory, evidenced by increased freezing behavior across the test trial. In contrast, male TBI mice displayed reduced freezing behavior with repetitive tone exposure. An inverse relationship in freezing behavior to tone exposure was detected between female sham and TBI mice, although the difference was not as striking. Together, these studies show that retrograde memory is intact after lateral TBI. However, male mice are more vulnerable to post-injury anterograde memory deficits. These behaviors were not associated with gross pathological change near the site injury or in subcortical brain regions associated with memory formation. Future studies that incorporate pre- and post-injury behavioral analysis will be integral in defining sex-specific memory impairment after TBI.

Self-organization into spatial patterns is evident in many multicellular phenomena. Even for the best-studied systems, our ability to dissect the mechanisms driving coordinated cell movement is limited. While genetic approaches can identify mutations perturbing multicellular patterns, the diverse nature of the signaling cues coupled to significant heterogeneity of individual cell behavior impedes our ability to mechanistically connect genes with phenotype. Small differences in the behaviors of mutant strains could be irrelevant or could sometimes lead to large differences in the emergent patterns. Here, we investigate rescue of multicellular aggregation in two mutant strains of Myxococcus xanthus mixed with wild-type cells. The results demonstrate how careful quantification of cell behavior coupled to data-driven modeling can identify specific motility features responsible for cell aggregation and thereby reveal important synergies and compensatory mechanisms. Notably, mutant cells do not need to precisely recreate wild-type behaviors to achieve complete aggregation. Single mutations frequently alter several aspects of cell behavior but rarely reveal whether a particular statistically significant change is biologically significant. To determine which behavioral changes are most important for multicellular self-organization, we devised a new methodology using Myxococcus xanthus as a model system. During development, myxobacteria coordinate their movement to aggregate into spore-filled fruiting bodies. We investigate how aggregation is restored in two mutants, csgA and pilC , that cannot aggregate unless mixed with wild-type (WT) cells. To this end, we use cell tracking to follow the movement of fluorescently labeled cells in combination with data-driven agent-based modeling. The results indicate that just like WT cells, both mutants bias their movement toward aggregates and reduce motility inside aggregates. However, several aspects of mutant behavior remain uncorrected by WT, demonstrating that perfect recreation of WT behavior is unnecessary. In fact, synergies between errant behaviors can make aggregation robust. IMPORTANCE Self-organization into spatial patterns is evident in many multicellular phenomena. Even for the best-studied systems, our ability to dissect the mechanisms driving coordinated cell movement is limited. While genetic approaches can identify mutations perturbing multicellular patterns, the diverse nature of the signaling cues coupled to significant heterogeneity of individual cell behavior impedes our ability to mechanistically connect genes with phenotype. Small differences in the behaviors of mutant strains could be irrelevant or could sometimes lead to large differences in the emergent patterns. Here, we investigate rescue of multicellular aggregation in two mutant strains of Myxococcus xanthus mixed with wild-type cells. The results demonstrate how careful quantification of cell behavior coupled to data-driven modeling can identify specific motility features responsible for cell aggregation and thereby reveal important synergies and compensatory mechanisms. Notably, mutant cells do not need to precisely recreate wild-type behaviors to achieve complete aggregation.