Texas Biomedical Research Institute

Obesity is an established risk factor for cardiovascular disease (CVD); however, the overall and sex-specific relationships across the full spectrum of body mass index (BMI), particularly severe obesity defined as class 2 (BMI 35 to <40.0 kg/m2) and class 3 (BMI ≥40 kg/m2), and long-term CVD outcomes remain incompletely described. We included 289 875 participants (mean age, 60.3 years; 79.2% women) from 21 cohorts of the Cross-Cohort Collaboration enrolled between 1948 and 2015 with harmonized BMI data, a BMI ≥18.5 kg/m2, and at least one of nine adjudicated outcomes: time to first fatal and non-fatal myocardial infarction (MI), fatal and nonfatal stroke, heart failure (HF), atrial fibrillation (AF), total coronary heart disease (CHD), total CVD, CHD mortality, CVD mortality, and all-cause mortality. Multivariable Cox proportional hazard models with restricted cubic splines were used to estimate the hazard ratio (HR) of BMI for each outcome, adjusting for demographic and clinical risk factors. Over 19.2 median years (25th, 11.6; 75th, 23.5 percentile) of follow-up, there were a total of 15 542 incident MI events, 15 467 incident stroke events, 14 172 incident HF events, 9066 diagnosed AF, and 113 918 total deaths, of which 14 647 were CHD-related and 28 879 were CVD-related. Overall, compared with individuals with normal weight, those with class 2 and class 3 obesity had the highest risk of HF (HR, 2.1, 95% CI, 2.0-2.3, and HR, 3.0, 95% CI, 2.7-3.2, respectively) and AF (HR, 1.8, 95% CI 1.7-2.0, and HR, 2.8, 95% CI, 2.5-3.1, respectively). Compared with men, women experienced higher relative increases in the risk associated with severe obesity for outcomes stroke, CVD, and all-cause mortality (P for interaction: <0.001, 0.003, and <0.001, respectively). Furthermore, in men, no increase in stroke risk was observed with higher BMI categories (P trend=0.49), whereas in women, the risk of stroke plateaued across obesity subclasses (compared with normal weight) yet remained significantly increased. Higher BMI was robustly associated with increased risk for most outcomes, particularly HF and AF, even after adjusting for traditional risk factors. Observed sex differences in the relative hazard of higher BMI categories and stroke, total CVD, and all-cause mortality suggest potential differences in underlying biological mechanisms.

BackgroundStroke is a leading cause of disability, with up to 80% of survivors experiencing motor impairments. These impairments are attributed to various factors, including reduced neural drive and altered motor unit firing patterns. Rehabilitation aims to restore motor function by enhancing motor unit recruitment and synchronization. High-density electromyography (HD-EMG) is a valuable tool for evaluating these changes in motor unit activity.MethodsWe tested a wearable HD-EMG forearm sleeve to investigate the relationship between motor function and motor unit properties including firing rate, motor unit module activation, and coherence. Seven individuals with chronic stroke and seven able-bodied individuals attempted 12 cued hand and wrist movements while EMG was recorded. Motor units were decomposed across all movements using convolutive blind source separation.ResultsFewer motor units were detectable in individuals with stroke compared to able-bodied participants. There was a significant reduction in motor unit firing rate during specific movements such as wrist flexion and hand open. Motor unit coupling and activation were altered following stroke, with reduced module activation in 8 of the 12 attempted movements. Furthermore, a reduction in coherence for gross movements and an increase in coherence for more dexterous thumb movements suggest altered neural drive to motor units after stroke that is differentially tuned to the complexity of movement. A combined neural control signature, consisting of multiple motor unit features, demonstrated strong correlation (R^{2}=0.81) with clinical motor function scores.ConclusionsThis study demonstrates that HD-EMG can capture detailed motor unit activity and neural control characteristics across multiple forearm muscles in individuals with chronic stroke. By integrating multiple HD-EMG features, this approach provides new insights into neuromuscular alterations linked to hand motor function after stroke. These findings support the use of HD-EMG for monitoring recovery, predicting outcomes, and guiding more targeted rehabilitation, thus advancing both stroke research and patient care.

Whether infection of cells by individual virions occurs randomly or if there is some form(s) of competition or cooperativity between individual virions remains largely unknown for most virus-cell associations. Here we studied cooperativity/competition for three different strains of human cytomegalovirus (HCMV) on two different cell types (fibroblasts and epithelial cells). By titrating viral inocula concentrations in small steps over several orders of magnitude, and by using flow cytometry to precisely measure frequency of infected cells, we found that for most virus-cell associations, the frequency of cell infection increases faster than linear with an increasing inoculum concentration, indicating cooperativity between individual infecting virions. Mathematical modeling suggests that this apparent cooperativity cannot be explained by heterogeneity in either the infectivity of the individual virions or the resistance of individual cells to infection, or by simple aggregation/clumping of viral particles. Stochastic simulations of two additional alternative models that allow for i) reduction in cell resistance to infection when exposed to multiple virions, or ii) compensation in infectivity of poorly infectious virions when coinfecting cells with more infectious virions, resulted in apparent viral cooperativity. Analysis of other published datasets suggests presence of apparent viral cooperativity for HIV and vaccinia virus, infecting CRFK or HeLa cells, respectively, but not for tobacco mosaic virus forming plaques on plant leaves. We thus 1) propose a methodology to rigorously evaluate apparent cooperativity of viruses infecting target cells, and 2) demonstrate that knowing the degree of virus cooperativity for any given virus-cell combination is important for an accurate quantification of multiplicity of infection (MOI).

The theory of developmental origins of health and disease suggests prenatal stressors, like synthetic glucocorticoids (sGC) administered to enhance fetal lung maturity, may predispose offspring to cardiovascular (CV) disease in later life. To investigate sex-specific CV outcomes, elderly baboon ( Papio spp.) offspring exposed prenatally to sGC (sGC: 4M/4F; ~17 yrs, ~70 human yrs equiv.) were compared to age/sex matched controls (CTR: 8M/5F). Cardiac magnetic resonance imaging (Siemens TIM Trio) assessed left ventricular (LV) structure, function, and myocardial strain. LV mitochondrial electron transport chain (ETC) function and protein expression were quantified, alongside RNA-seq analysis for differential gene expression and alternative splicing. In elderly males, sGC exposure resulted in LV remodeling indicated by increased end-systolic (p=0.027) and end-diastolic (p=0.00013) sphericity indexes and elevated paracardial adipose thickness (152% &gt; CTR, p=0.016). Male sGC baboons showed impaired myocardial strain, including decreased radial (p=0.03) and longitudinal (p=0.041) strains and reduced early longitudinal strain rate (p=0.009). Mitochondrial function in male sGC baboons revealed decreased Complex I-linked respiration (33.5% lower, p=0.002) and Complex I protein subunit NDUFV2 expression (p=0.048). Transcriptomic profiling in males identified 83 differentially expressed genes enriched in pathways involving extracellular matrix remodeling (TGFB2, POSTN), inflammation (IL33), and fibrosis (OGN). Alterations in alternative splicing (38 clusters, primarily exon skipping events) linked RNA-binding proteins (e.g., TIA1, HNRNPC) to cardiac dysfunction. Principal component analysis highlighted distinct sex-specific clustering, reinforcing observed sexual dimorphism. Female sGC-exposed baboons displayed fewer cardiac changes on MRI, limited mitochondrial alterations, minimal gene expression shifts (4 genes), and reduced splicing alterations (16 clusters), suggesting intrinsic cardioprotective mechanisms. Integrative correlation analyses linked transcriptomic and mitochondrial changes to cardiac phenotypes, specifically in males, highlighting potential biomarkers for early detection and targets for therapeutic intervention. These results underscore the importance of sex-specific long-term CV monitoring in individuals prenatally exposed to synthetic glucocorticoids, informing clinical strategies for prevention and management.

New vaccine approaches are needed against tuberculosis (TB). We sought to optimize mucosal immunogenicity and protective efficacy by modulating the adjuvant component and route of immunization of a next-generation TB vaccine using the recombinant TB vaccine antigen (Ag) ID93. ID93-specific mucosal and systemic immunogenicity and protective efficacy were assessed in the Collaborative Cross 004 mouse strain, a mouse strain susceptible to Mycobacterium tuberculosis (Mtb) infection, as a suitable model of Mtb susceptible populations. Immunogenicity data from various vaccine candidates were used to select lead vaccine candidates with the most preferred immunostimulatory profiles using a pre-determined desirability index. A liposomal adjuvant system containing synthetic TLR4 and TLR7/8 ligands (GLA-3M-052-LS), administered by a heterologous intramuscular-intranasal regimen, induced an optimal comprehensive immune response profile including high levels of mucosal antibody and Th1 CD4+ T cells in the lungs. In BCG-primed mice, immunization with intramuscular followed by intranasal ID93 + GLA-3M-052-LS boosts significantly reduced Mtb burden in the lungs after challenge vs. BCG vaccinated mice alone. Thus, ID93 + GLA-3M-052-LS represents a promising next-generation TB vaccine candidate suitable for testing in additional preclinical models.

Abstract Description Mucosal-associated invariant T (MAIT) cells recognize microbial-derived metabolite antigens presented by MR1 and play crucial roles in early antimicrobial defense. While their responses to microbial infections are well-studied, MAIT cell activation and cytotoxicity against cancer cells remain unclear. This study investigates MR1-dependent activation of MAIT cells and their cytotoxicity in response to cancer cell lines. We evaluated MAIT cell responses to bacterial or mammalian antigens presented by cancer cells, including K562 (myelogenous leukemia) and U251 (glioblastoma), by measuring IFN-γ production. MAIT cells showed elevated IFN-γ+ spots when stimulated with small molecule eluates from Mycobacterium tuberculosis or Escherichia coli, compared to unstimulated controls. MR1-blocking antibodies significantly reduced IFN-γ production, confirming MR1-restricted activation by both bacterial and mammalian antigens. To assess effector functions, clonal and polyclonal MAIT cells were co-cultured with K562.hMR1 and U251 cells. AlamarBlue assays revealed reduced U251 proliferation and viability, while lactate dehydrogenase assays indicated increased cancer cell death, supporting potential MAIT cell-mediated cytotoxicity. These findings underscore the role of MR1 in mediating MAIT cell recognition of microbial and mammalian antigens and highlight MAIT cells potential for anti-cancer responses, suggesting mammalian antigens as promising targets for alternative immunotherapies. Funding Sources Grant ID: RP240605 Sponsor: Cancer Prevention &amp; Research Institute of Texas (CPRIT) Grant ID: 1R01AI173245-01A1 Sponsor: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES (NIAID) Topic Categories Antigen and Dendritic Cell Processing, Presentation, and Biology (AGDC)

Influenza viruses cause mild to severe lower respiratory infections, sometimes resulting in hospitalization and death. Vaccination remains the primary prophylactic strategy. Live attenuated influenza vaccines (LAIVs) efficiently induce antiviral immune responses and contain temperature-sensitive and cold-adapted mutations that render them safe. These mutations are principally located in the PB1 and PB2 subunits of the viral RNA polymerase, but the mechanism by which they attenuate the virus is unclear. We introduced the PB1 and PB2 mutations from two LAIV backbones, A/Ann Arbor/6/1960 H2N2 (AA) and A/Leningrad/134/17/1957 H2N2 (Len), into the model influenza strain A/Puerto Rico/8/1934 H1N1 (PR8). In contrast to the wild-type (WT) PR8 polymerase, the two “PR8-LAIV” polymerase complexes demonstrated maximal activity at cold temperatures (30–32 °C) and greatly reduced activity at elevated temperatures (>37 °C). To further understand the impact of the LAIV mutations, we infected MDCK cells with WT and mutated PR8 viruses that contain the Len and AA LAIV mutations in PB1 and PB2. The PR8-LAIV mutant viruses exhibited a selective, temperature-dependent defect in the replicase activity of the viral RNA polymerase relative to WT PR8, while also demonstrating a temperature-dependent enhancement in the transcriptional activity of the enzyme. In addition, the PR8-LAIV mutant viruses produced similar levels of viral proteins to WT PR8 at 37 °C, but greatly (2–3 log10) reduced levels of infectious viral progeny. Collectively, these data show that LAIV mutations selectively alter influenza viral RNA polymerase function, favoring transcription over genome synthesis at 37 °C, thereby preserving viral antigen production while also contributing to viral attenuation.

Monoclonal antibodies (mAbs) that recognize and inhibit a diverse range of influenza viruses, although relatively rare, have been isolated following infection or vaccination. Study of their ontology and mechanisms of action informs universal vaccine and therapeutic development. We have previously described a potent and broad neuraminidase (NA)-neutralizing human mAb, 1122A11, that neutralizes a wide range of H3N2 viruses. Here, further characterization of 1122A11 reveals reactivity to cross-group influenza A virus NAs, including group-1 N1 and N8, and group-2 N2 and N3 NAs. Recent H3N2 viruses have acquired Asn245 glycosylation on the active site rim. Crystal structures of an N2 NA from A/Singapore/INFIMH-16-0019/2016 (H3N2) at 2.3 Å (apo) and 2.2 Å (Fab bound) resolution showed that 1122A11 binding causes local changes to the periphery of NA active site to accommodate the glycan. The CDRH3 of 1122A11 inserts into the active site and mimics the substrate sialic acid. We then determined that the ability of 1122A11 to protect from lethal challenge in mice is not dependent on Fc-effector function. These results highlight the therapeutic potential of 1122A11 as a broad protective anti-viral and reinforce pursuit of immunogen development of NA antibodies toward achieving more universal influenza protection.

ABSTRACT Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), uses human angiotensin converting enzyme 2 (hACE2) as its obligate receptor for cell entry. The K18 hACE2 transgenic mouse line, which expresses hACE2 under control of the human keratin 18 (K18) promoter, is used as an animal model for the study of COVID-19 pathogenesis. Here, we evaluate this model in the screening of human monoclonal antibody (hmAb) therapies against SARS-CoV-2. We included 206 hmAbs from the Coronavirus Immunotherapeutic Consortium Database (CoVIC-DB) and identified many that protected against a lethal challenge with the virus. Our data showed that mouse weight change from day 5 onward highly correlated with survival. Many of the protective hmAb candidates we identified also showed strong viral neutralization and spike protein (SP) binding when measured in vitro ; however, in many cases, in vitro assays failed to identify protective hmAbs, suggesting that the mouse model may capture characteristics of the hmAbs that other methods cannot. Our findings demonstrate the relevance of including in vivo models for the characterization of therapeutics against SARS-CoV-2, as these improve both accuracy and expediency in the screening process.