Objectives/Goals: The objectives of the study were to evaluate end-user feedback regarding usefulness and compliance with the revised DoD PRA-CR. The PRA-CR utilizes symptom-guided management strategies to advance service members with acute concussion through 6 stages of gradually increased activity prior to their Return to Duty (RTD). Methods/Study Population: Clinical providers previously trained on the PRA-CR were invited via email to participate in an online survey-based study to examine their opinions and utilization of the revised PRA-CR. Participants who responded to the initial email invitation were provided an electronic Microsoft Forms based survey. Of the 83 total responders, 36 met inclusion criteria and advanced to the end-user survey. Six items were designed to assess inclusion–exclusion criteria (i.e., credentialed medical provider trained in the PRA-CR with experience treating concussion over the previous 2 years). Four items gauging utilization required yes/no responses; 20 opinion items on a 7-point Likert scale ranged from strongly disagree to strongly agree; 5 explanatory items were multi-select; and 1 item allowed free text responses. Results/Anticipated Results: Overall, 87% of respondents who had used the revised CR indicated that it helped them treat patients with acute concussion and 73% rated, “ease of use” favorably. Of the newly added elements to the CR, utilization of the Patient Leadership Guide (PLG) was the highest at 78%, with the majority of the providers rating the PLG as useful in communicating with patients and command. In contrast, only 35% of participants reported using the Physical RTD screening section and 22% indicated using the Cognitive RTD screening tool. Those not utilizing the Physical screening identified a lack of support staff (67%) or setting barriers (47%) as the primary reasons. Those not utilizing the Cognitive RTD screening tool identified multiple barriers to use including availability (72%), inexperience (39%), and baseline data access (33%). Discussion/Significance of Impact: This study sought end-user (provider) feedback regarding the revised PRA-CR’s usability and utility, in addition to their confidence in the tool itself. Overall results were generally positive, except for the updated Physical RTD and newly introduced Cognitive RTD screenings.

Objectives/Goals: This study assesses the feasibility of a human-to-swine lung transplant model for the evaluation of bioengineered organs. Given the critical organ shortage, this research explores bioengineered organs as a potential solution by evaluating early lung function, immune responses, and technical aspects to develop a model for bioengineered lungs. Methods/Study Population: The study employs a non-survival human-to-swine left lung transplant model in an immunosuppressed Yorkshire swine. A combination of cobra venom factor pretreated with methylprednisolone and Benadryl with scheduled dosing of tacrolimus and mycophenolate over a 24-hour period will be administered. The transplanted human lung is assessed over a 24-hour post-transplant period, with hourly pulmonary vein gas sampling and lung tissue resections. The proposed model will assess the immunological response of swine to human lung tissue as well as the efficacy of the immunosuppression model. Tissue samples are taken at intervals to evaluate for signs of rejection, cellular damage, and the overall function of the transplanted lung. All tissues are preserved in formaldehyde for subsequent immunohistology evaluation. Results/Anticipated Results: We anticipate a successful non-survival swine transplant model with pulmonary function sustained for the full 24-hour study using our proposed immunosuppression regimen. Initial testing with a standard human lung will lay the groundwork to assess the effectiveness of the human-to-swine transplant model. Hourly pulmonary vein gas analyses and tissue biopsies are expected to show minimal immune rejection, supported by the preoperative immunosuppression regimen. Early data indicate that the swine tolerates both the surgical procedure and immunosuppressive therapy well, with manageable hemodynamic stability. This model is expected to yield critical insights into lung viability and will identify areas for optimization for long-term survival studies to test the efficacy of bioengineered organs. Discussion/Significance of Impact: This non-survival swine model offers valuable insights into the acute-phase immune response and functional viability of human-to-swine lung transplant model. The findings will support the development of long-term survival models that will allow the evaluation of bioengineered organs based solely on their functionality as engineered organs.

Objectives/Goals: Motivational deficits are associated with depression and poorly treated by current therapeutics. We sought to identify more effective therapeutics for these deficits using a mouse model of early-life exposure to SSRIs, a developmental risk factor identified for depression in humans. Methods/Study Population: Mice were administered the SSRI, fluoxetine (FLX), or a vehicle control from postnatal day P2-P11, a window that mimics brain development occurring during the third trimester in a human pregnancy. Motivation and hedonic perception were assessed in adulthood using the progressive ratio and lickometer tasks, respectively. Behavioral testing was repeated after chronic adult administration of either an SSRI (fluoxetine), an atypical antidepressant and mu-opioid receptor agonist (tianeptine), or a mu-opioid receptor antagonist (methocinnamox). Results/Anticipated Results: Mice administered FLX in early-life showed motivational deficits in the progressive ratio task, while hedonic perception, as measured by the lickometer task, remained intact. Chronic administration of FLX in adulthood did not improve motivational deficits and did not alter hedonic perception. Chronic administration of tianeptine (TIA) slightly improved motivational behavior without altering hedonic perception. In contrast, chronic administration of the mu opioid antagonist methocinnamox (MCAM) markedly improved motivational deficits in mice, even while blunting hedonic perception. The ability of MCAM to enhance motivation was selective to early-FLX exposed mice Discussion/Significance of Impact: Our results reveal that unexpectedly opioid receptor antagonism is effective at improving motivation in mice exposed to SSRIs in early life. This suggests potential novel treatment approaches in individuals with motivational impairments and a history of in utero exposure to SSRIs.

Objectives/Goals: Our research addresses critical gaps by examining the prevalence, blood concentrations, and health implications of xylazine abuse, with a focus on its cardiotoxic effects. We aim to map the geographic distribution of xylazine use across Puerto Rico and characterize its impact on cardiomyocytes at relevant exposure levels. Methods/Study Population: To accurately detect and quantify xylazine in blood samples, we will employ chromatographic techniques coupled with mass spectrometry (UPLC/MS or GC/MS). The xylazine prevalence across the island will be mapped based on health system classifications. Samples will be categorized according to the eight healthcare regions of Puerto Rico, as defined by the “Administración de Seguros de Salud” (ASES), ensuring comprehensive geographic representation. We will investigate the expression profiles of proteins associated with cardiac injury and dysfunction in human cardiomyocytes and in the blood of drug users. Blood samples will be provided by “Iniciativa Comunitaria.” We will assess the xylazine effects on human cardiomyocyte viability and identify key biomarkers of cardiotoxicity induced by xylazine exposure. Results/Anticipated Results: In previous research, we demonstrated that xylazine induces cell death in endothelial cells through both extrinsic and intrinsic pathways. We also observed an increase in reactive oxygen species (ROS) levels after drug exposure, indicating oxidative stress as a potential mechanism of toxicity. Additionally, DNA damage was detected. Given the known relationship between endothelial damage and cardiomyocyte dysfunction in drug-induced cardiotoxicity, we hypothesize that xylazine concentrations vary regionally within Puerto Rico and that chronic xylazine abuse will elevate markers of cardiac injury and dysfunction at common user doses. Discussion/Significance of Impact: The increasing xylazine abuse, particularly in Puerto Rico, represents a critical public health challenge. Our study will fill a knowledge gap by providing crucial data on xylazine’s cardiotoxicity and mapping its geographic prevalence, with the potential to advise healthcare approaches and improve care for drug-using Hispanic populations.

Objectives/Goals: The goal of this study is to determine the function of the rete ovarii (RO), an uncharacterized secretory epithelial appendage to the ovary. I am testing the hypothesis that the RO is critical for the maintenance of the ovarian reserve and fertility, and progesterone signaling plays a role in the function of the RO. Methods/Study Population: For this project, I am utilizing a mouse model. To visualize the rete ovarii (RO) in vivo, I am using a Pax8rtTA; TRE-H2B-Gfp (PTG) reporter mouse, which expresses green fluorescent protein in the RO. To determine the role of the RO in fertility and maintenance of the ovarian reserve, I will surgically ablate the RO or perform a sham surgery on adult female PTG mice. Then, I will follow-up with quantification of the ovarian reserve and long-term fertility tracking studies. To determine how the RO responds to progesterone, the RO will be cultured ex vivo in the presence and absence of progesterone. I will perform a morphometric analysis of the RO, as well as collect secreted proteins from the media for proteomic analysis. Results/Anticipated Results: If the RO is important for ovarian homeostasis, I expect that in the absence of the RO, ovarian functions such as maintenance of the ovarian reserve and fertility will be impaired. Additionally, because the RO expresses progesterone receptors, I anticipate that the RO will be responsive to progesterone as shown in changes in the morphometric analysis and in changes in secreted proteins in the presence of progesterone. Discussion/Significance of Impact: A major gap in knowledge regarding female physiology and reproductive health is the role of the RO. We expect this work to reveal that progesterone signaling in the RO is important for regulating ovarian functions and to show that the RO is a critical modulator of female fertility and reproductive function.

Objectives/Goals: A key strategy in generating a protective HIV vaccine is the elicitation of broadly neutralizing antibodies (bnAbs), capable of neutralizing a large diversity of HIV-1 isolates. The goal of this study is to identify molecular signatures of HIV bnAb development early in life, to guide the development of a successful pediatric HIV vaccine strategy. Methods/Study Population: We previously defined HIV neutralization breadth in 40 ART-naive children living with HIV. Single-cell RNAseq was performed utilizing peripheral blood mononuclear cells (PBMCs) from the top 5 children with highest neutralization breadth scores and compared their transcriptome to that of PBMCs from 5 children that did not develop neutralization breadth within the first three years of life. Additionally, we incorporated analysis of PBMCs from 5 healthy uninfected children, matched to our experimental groups by race, ethnicity, and gender. Results/Anticipated Results: We expect that a distinct host transcriptional profile is associated with the development of HIV-specific antibody neutralization breadth in early life. Discussion/Significance of Impact: Identifying immune cell transcriptional profiles associated with neutralization breadth will lead to more targeted vaccine approaches for eliciting the appropriate B cell responses and provide an invaluable screening tool allowing early identification of vaccine candidates with the potential to induce bnAbs.

Objectives/Goals: Cerebral amyloid angiopathy-related inflammation (CAA-ri) is a spontaneous inflammatory cerebral vasculopathy that mimics complications of Alzheimer’s disease immunotherapies. Our objective is to evaluate imaging and cerebrospinal fluid (CSF) markers of blood–brain barrier (BBB) impairment and inflammation in CAA-ri. Methods/Study Population: We plan to enroll 20 patients total: 1) 10 patients with CAA-ri as defined by Auriel et al (JAMA Neurology 2016) (exposure group). 2) 10 patients with non-inflammatory CAA defined using Boston criteria 2.0 that do not also meet criteria for CAA-ri (control group). The primary outcome will be Ktrans, a parameter of BBB impairment calculated from dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) of the brain. Secondary outcomes will include DCE-MRI parameter VL, CSF albumin index, CSF fibrinogen, CSF sPDGFR-β, CSF MMP-2, CSF MMP-9, CSF C3, CSF IL1β, CSF IL6, IL8, and TNFα. Statistical comparisons between the exposure and control groups will be made using Wilcoxon rank sum test. Results/Anticipated Results: We anticipate significantly higher levels of BBB impairment and inflammatory biomarkers from DCE-MRI and CSF in subjects with CAA-ri relative to control subjects with non-inflammatory CAA. Discussion/Significance of Impact: Biomarkers are essential to characterize risk factors, pathophysiology, and possible treatment targets in CAA-ri. We plan to use the results of the current study to inform longitudinal studies that will test whether these markers are useful in identifying not only the presence of CAA-ri but also severity, progression, and response to treatment.

Objectives/Goals: Men and women with opioid use disorder (OUD) show differences in their initiation, use patterns, and outcomes that may have biological underpinnings. Here we present data directly comparing adult male and female rats across heroin-induced behaviors in order to provide insight into the nuances of sex differences in OUD. Methods/Study Population: We first used a 6-hour intermittent access heroin self administration paradigm to quantify six distinct drug-taking and drug-seeking behaviors. Based on the sum of the z-scores for each behavior, we classified rats as having high- or low-severity phenotypes. In a separate group of rats, we adapted this classification system to a 10-minute continuous access self-administration paradigm to better represent the timeframe of use common in people. Finally, we examined locomotor sensitization following daily heroin injections in two groups of rats. The first were given 2 mg/kg/day i.p. heroin for 10 days and the second were given 0.55 mg/kg/day i.v. heroin for 20 days. Results/Anticipated Results: In the 6-hour intermittent access, both sexes showed variability across individuals, but a greater proportion of females were classified as having a high-severity phenotype compared to males. This difference in severity distributions was also found in the 1-hour continuous access experiment. Consistent with the literature, in our sensitization experiments, we found that males had a lower baseline level of locomotion compared to females. Across sex and route of administration, rats treated with heroin initially decreased locomotion, but returned to baseline over the course of treatment. Females given i.v. infusions showed a rapid escalation of locomotion past baseline that was not seen in males or following i.p. injections. Discussion/Significance of Impact: Our results indicate a consistent pattern of females having a greater behavioral response to heroin compared to males. This suggests a sex-based effect on OUD that may interact with gender-based influences. As such, future research needs to consider sex in the development of treatments for OUD and other substance use disorders.

Objectives/Goals: This study aims to uncover immuno-endotypes in sepsis-associated pediatric acute respiratory distress syndrome (SA-PARDS) by using single-cell RNA sequencing (scRNA seq) to analyze the immune cell populations of the lower respiratory tract of intubated pediatric subjects with SA-PARDS. Methods/Study Population: Inclusion criteria are age less than 18 years, admission to the PICU, diagnosis of SA-PARDS, and intubation. Both sepsis and PARDS will be defined using the most recent consensus definitions. Exclusion criteria include an order of limited resuscitation and clinician discretion. After informed consent is obtained, a tracheal aspirate and blood sample will be obtained on days 1, 3, and 7. Both samples will be processed for single-cell RNA seq via the HIVE platform per manufacturer protocol. cDNA libraries will then be sent for 150 base pair paired-end sequencing. Sequences will be aligned to a reference genome, and count matrices will be generated. The Seurat package in R will be used for cell-type annotation and analysis of differential gene expression. Clinical variables, labs, and outcomes will be recorded in REDCap. Results/Anticipated Results: We expect to find that subjects with nonresolving SA-PARDS, defined as intubation and mechanical ventilation, will have a monocyte/macrophage transcriptome characterized by continued hyper-inflammation (M1-like phenotype) that does not transition over time to an anti-inflammatory and pro-repair phenotype (M2-like). Additionally, we expect to see that subjects with non-resolving SA-PARDS will have evidence of continued inflammation driven by hyper-inflammatory neutrophils. Finally, we expect that subjects with non-resolving SA-PARDS will have epithelial cells characterized by continued upregulation of canonical pathways of innate immunity including interferon signaling and the damage associated molecular pattern recognition pathway. Discussion/Significance of Impact: The discovery of immuno-endotypes in SA-PARDS would represent a major step toward developing precision medicine therapies for this group of patients. It would simultaneously provide a strategy to reduce biological heterogeneity and identify novel pathways and targets for therapy.

Objectives/Goals: * Examination of the acute glucose-lowering response to physical activity within a comprehensive behavioral weight loss intervention in adults without T2DM. * Explore whether the acute response to yogadiffers from the acute response to brisk walking and to examine whether these responses vary across the intervention period. Methods/Study Population: Participants in the behavioral weight loss and aerobic exercise group will start with 100 minutes per week of moderate-intensity aerobic activity, increasing every four weeks to 250–300 minutes, spread over five days. Activities will be self-selected, such as walking. Participants in the combined aerobic exercise and yoga group will do aerobic exercise three days a week and yoga two days a week, also progressing from 100 to 250–300 minutes weekly. All participants will follow an energy-restricted diet (1200–1800 kcal/day) and participate in weekly education sessions to learn lifestyle modification skills for successful weight loss. The study will explore differences in acute responses to yoga versus walking and how these vary during the intervention, controlling for initial and changing weight status. Results/Anticipated Results: Primary and secondary outcomes from the parent study will include body weight, BMI, body composition (via DXA), cardiorespiratory fitness, energy intake, and physical activity. Glucose and insulin levels will be measured pre- and post-exercise, with HOMA-IR computed. Continuous glucose monitoring (CGM) will be used to track glucose responses during each session, with the area under the curve (AUC) as the primary metric. The study will also explore advanced CGM analytics in collaboration with the KUMC Diabetes Institute that will include in-depth analyzation of peak and trough change velocity as well as novel correlations betwen glucose dynamics and physical activity patterns with an aim to uncover insights that transcend conventional CGM analyses. Discussion/Significance of Impact: This study uses advanced CGM analytics to examine glucose control during physical activity, collaborating with experts to create comprehensive models for glucose fluctuations. It compares acute responses to walking and yoga, addressing a key gap in research, with potential clinical insights for managing glucose in obesity.

Objectives/Goals: Diamond Blackfan anemia (DBA) is caused by loss of ribosomal proteins leading to death of red blood cell progenitors. We identified a novel heterozygous variant (c.167+769C>T) in RPL30 in a patient with DBA. We hypothesized that this variant, in a gene not previously studied in DBA, would demonstrate DBA phenotype and reveal early drivers of disease. Methods/Study Population: To study the role of our novel variant, we developed an induced pluripotent stem cell (iPSC) model, including wild type (WT) and CRISPR-edited RPL30 mutant clones. We differentiated the iPSC into hematopoietic stem cells, identified cell populations with flow cytometry, and applied single-cell RNA sequencing. We identified erythroid clusters for differential gene expression analysis, using R Studio DESeq followed by Gene Ontology (GO) enrichment analysis. We are differentiating cells into red blood cells for further comparison with flow cytometry, bulk RNA sequencing, protein analysis, and hemoglobin staining. Our approach has relied on multidisciplinary expertise in clinical hematology and genetics, basic science study of ribosomes, computational biology, stem cell, and hematopoietic biology. Results/Anticipated Results: Compared to WT hematopoietic stem cells, RPL30mutant cells had significantly decreased expression of RPL30. Analysis of top differentially expressed genes revealed downregulation of HSPA1A which encodes heat shock protein 70 (HSP70), chaperone of a critical red blood cell transcription factor. Loss of HSP70 protein has been implicated in RPL-mutated red blood cells previously as a potential modulator of severe DBA phenotype. Upon GO enrichment analysis of downregulated genes, biologic process terms GO:0042254 ribosome biogenesis, GO:1903708 positive regulation of hemopoiesis, and GO:0045646 regulation of erythrocyte differentiation were all highlighted as driver terms. We expect further differentiation to reveal early death of RPL30mutant cells with associated downregulated HSP70. Discussion/Significance of Impact: Our results support our hypothesis that the RPL30 variant downregulates erythropoiesis, with a potential early role of HSP70 protein. Upon completion of our study, we will demonstrate the role of RPL30in DBA pathogenesis as well as provide understanding of its drivers, which is critical for improved management of this disease.

Objectives/Goals: Explore and compare the functional mechanisms of song-based exercises compared to speech-language pathology exercises for dysphagia. The long-term goal is to increase patient outcomes through song-based programs that are accessible, enjoyable, and personalizable. Methods/Study Population: We will pilot the use of combined electroencephalography (EEG) and electromyography (EMG) technologies to analyze both central and peripheral contributors to laryngeal control in a cohort of healthy individuals. This approach provides detailed insight into the coordination between neural and muscular activity, which will serve as a baseline for future studies in clinical populations. Song-based vocal exercises will be compared with standard dysphagia exercises prescribed by speech-language pathologists to assess their mechanistic differences. Results/Anticipated Results: We anticipate identifying specific song-based tasks, such as variations in pitch, rhythm, and intensity, which differentially impact laryngeal musculature. Additionally, we will localize neural activation hotspots using EEG during these tasks, providing a more comprehensive understanding of how song-based therapy influences both peripheral and central mechanisms. Discussion/Significance of Impact: This project will lay the groundwork for developing evidence-based song-based therapies for dysphagia, providing an alternative to traditional SLP exercises. By creating an engaging therapeutic program, we aim to reduce dysphagia’s healthcare burden, including aspiration events, healthcare costs, and related mortality.

Objectives/Goals: The creatine (Cr) system is impaired in Alzheimer’s disease (AD). Data show that creatine monohydrate (CrM) supplementation may improve AD symptoms in AD mouse models, but no human studies have been reported. Thus, we investigated whether an eight-week CrM supplementation was feasible and associated with increased brain creatine in patients with AD. Methods/Study Population: Twenty participants with probable AD were allocated to an open-label, eight-week intervention of 20 g/day CrM. Fasting blood draws were taken at baseline, 4-, and 8-week visits to measure serum creatine (Quest Diagnostics). 1H magnetic resonance spectroscopy was performed at baseline and 8-week visits to measure brain Cr as a ratio to unsuppressed water. Self-reported compliance (with assistance from study partners) was assessed with daily CrM trackers. The mean compliance percentage across all participants was used to describe overall compliance with the intervention. We used paired t-tests to analyze the mean changes in serum Cr levels from baseline to 4- and 8-week visits and the mean change in brain Cr from baseline to 8-week visits. Statistical significance was set at p<0.05. Results/Anticipated Results: Participants were 65% male with a mean age of 73.1±6.3 years. All participants completed the study, with 19 out of 20 achieving the dose compliance target of ≥80%. The mean self-reported dose intake was 90%. Serum Cr levels were significantly increased at 4- and 8-week visits compared to baseline (0.6±0.4 mg/dL vs. 14.0±9.9 mg/dL and 15.0±13.6 mg/dL, respectively; p<0.001). Brain Cr levels also significantly increased (330.5±36.80 i.u. vs. 366.9±57.52 i.u., p<0.001). Discussion/Significance of Impact: We are the first to demonstrate that 20 g/day of CrM for eight weeks is feasible and associated with increased brain Cr in patients with AD. Our findings support further investigation of brain target engagement of CrM and its efficacy in AD. With AD cases expected to rise, CrM could serve as an effective, affordable therapeutic to slow AD progression.

Objectives/Goals: The study focuses on developing a wound patch that employs a biocompatible matrix which incorporates mesenchymal stem cells (MSCs) with wound healing and antimicrobial properties, along with antimicrobial metallic nanoparticles covered with keratinocytes derived from induced pluripotent stem cells to replicate the skin’s barrier function. Methods/Study Population: In vitro experiments will be conducted to combine bacteria with MSCs and metallic nanoparticles to assess whether bacterial killing is improved by this combination. The MSCs will then be evaluated in the presence of the nanoparticles to confirm that their functionality and phenotype are not altered. To verify the cells’ functional integrity, they will undergo trilineage differentiation, surface marker phenotypic testing, and evaluation of their capacity to inhibit lymphocyte proliferation in the presence of the nanoparticles. Subsequently, this living bandage will be created using a biomatrix embedded with induced pluripotent stem cell-derived keratinocytes and tested on a canine wound model to study the impact on healing. The model will assess the rate of healing and cellular response at weekly intervals until healed. Results/Anticipated Results: The combination of mesenchymal stem cells and antimicrobial nanoparticles works synergistically to enhance bacterial killing in vitro with S. aureus. The presence of the nanoparticles in combination with MSC did not affect the ability of the MSC to undergo trilineage differentiation. We anticipate that the surface phenotype will be similarly unaffected. In addition, we expect that the presence of the nanoparticles should not interfere with the ability of MSC to suppress lymphocyte proliferation. Utilization of the wound patch in the in vivo canine wound model is expected to enhance healing and prevent infection. We expect that we will observe a shift in the cellular composition of the wound with less inflammatory cells and more M2 or wound healing anti-inflammatory monocytes. Discussion/Significance of Impact: The incidence of resistant infections with no pharmacologic therapy available are on the rise. The development of an antimicrobial living bandage that increases the body’s ability to fight off infection, while providing a barrier to reinfection would provide a new way to treat infections regardless of their acquired antibacterial resistance.

Objectives/Goals: Evaluate the impact of intrauterine growth restriction (IUGR) on neonatal brain development using magnetoencephalography (MEG) and correlate findings with NICU Network Neurobehavioral scale (NNNS) scores at 1 month Methods/Study Population: In this prospective cohort study, we will enroll 30 participants, consisting of 15 neonates diagnosed with IUGR and 15 healthy controls, matched by gestational age, from the University of Arkansas for Medical Sciences. We will perform MEG scans at three key developmental stages: during fetal life, at 1 month, and at 3 months of age and a Bayley IV exam at 12 months of age. The NNNS assessments will be conducted at the 1-month visit to evaluate neurobehavioral outcomes. All MEG data will be synchronized with clinical evaluations and maternal health records to ensure comprehensive analysis. Results/Anticipated Results: We anticipate that the study will reveal significant differences in brain maturation and neural activity patterns between IUGR-affected infants and healthy controls. Specifically, we expect to find altered neural connectivity and delayed maturation in the delta and theta frequency bands during the early neonatal period in the IUGR group. These anticipated neuroimaging findings will be correlated with NNNS scores to assess functional implications of the observed brain activity differences. If our hypotheses are confirmed, the study will provide robust biomarkers for early identification of neurodevelopmental delays in IUGR-affected infants, paving the way for targeted early interventions. Discussion/Significance of Impact: This study could significantly enhance early detection and intervention strategies for IUGR, potentially reducing long-term neurodevelopmental challenges and improving clinical outcomes

Objectives/Goals: Tacrolimus (TAC) is an immunosuppressant used after hematopoietic stem cell transplant (HSCT). Recently, TAC was found to be metabolized to a novel, less active metabolite by common gut microbiota. Our objective is to determine a microbiome signature that influences oral TAC pharmacokinetic (PK) and to develop a clinical tool to select the TAC dose. Methods/Study Population: This is an observational IRB approved microbiome-pharmacogenomic study using banked biospecimens and clinical data, TAC dose, and PK information from the electronic health record. Adult HSCT patients with pre-transplant DNA and stool specimens were included in this analysis if they received TAC in the first 100 days post-HSCT. A global diversity array was used for DNA pharmacogenomic (PGx) genotyping, and metagenomic shotgun sequencing was used for stool microbiome analysis. Spearman correlation will be used to identify potential stool microbiota associated with TAC PK. TAC trough concentrations at steady state will be modeled using nonlinear mixed effects (NLME) modeling to identify potential genetic and microbiota covariates that influence TAC clearance. Results/Anticipated Results: We identified 53 eligible patients who had available DNA and 90 stool samples. The majority (n = 49, 92.5%) were of European ancestry. These patients had 920 (oral  =  622, IV infusion  =  298) TAC trough blood concentrations. We expect that patients who have high abundance of bacteria that metabolize or reduce the absorption of TAC will have lower blood concentrations and will require a higher IV to oral dose conversion ratio than those with lower abundance. Those patients will also require higher oral TAC daily doses. Low stool microbial diversity is expected to be associated with high oral TAC trough intra-patient variability in the first 100 days post-transplant. In the NLME model, PGx when combined with potential bacterial signature will better explain variability in TAC clearance. Discussion/Significance of Impact: Combining PGx and microbiome biomarkers will provide a better understanding of the factors influencing TAC PK and lead to models for individualized dosing. To our knowledge, this is the first study to investigate the combined influence of microbiome and PGx on drug PK. The study is limited to the availability of samples in the biobank.

Objectives/Goals: Germinal matrix hemorrhage (GMH) is a devastating disease of infancy that results in brain-related pathologies. Following rupture of vasculature in the brain, red blood cell (RBC) lysis, and hemoglobin breakdown results in heme/iron-related toxicities. We hypothesize that these cellular pathologies are mediated in part by the complement system. Methods/Study Population: Post-natal mice on day 4 (P4) were subjected to collagenase induced-GMH and treated with various complement inhibitors that function at different points in the complement pathway and differentially prevent the generation of specific complement activation products. The principle bioactive complement activation products are C3 opsonins (C3b, iC3b, and C3d), the proinflammatory anaphylatoxins (soluble C3a and C5a peptides), and the terminal cytolytic membrane attack complex (MAC). Experimental groups consisted of: Wild-type (WT) naïve mice, and WT GMH-mice treated with either PBS (vehicle), CR2-Crry (C3 inhibitor that blocks all activation products), anti-C5 mAb (blocks C5a and MAC), C5aRA (blocks C5a-C5a receptor interaction), or anti-C7 mAb (blocks MAC). Study endpoints were P7 or P14. Results/Anticipated Results: Following GMH, CR2-Crry treatment decreased MAC deposition on RBC and additionally decreased heme oxygenase-1 expression, heme deposition, and iron-induced inflammation measured at P7. In support of a specific role for the MAC, anti-C7 mAb treatment resulted in similar outcomes and was similarly protective. Anti-C7 mAb treatment also reduced hydrocephalus development at a later time point (P14). A similar result was obtained using C7 deficient mice and with anti-C5 mAb treatment. On the other hand, no protective effect was seen with C5aR blockade, and double knock out of C3aR/C5aR also did not provide protection, indicating no role for the anaphylatoxins C3a and C5a and their receptors expressed on leukocytes and endothelial cells in exacerbating deteriorating outcomes. Discussion/Significance of Impact: Our data indicate a key role for the MAC in RBC induced hemolysis after GMH which serves as a driver of inflammation and early GMH pathogenesis. We further show that we can effectively increase precision by targeting solely the MAC complex acutely. Future work will be undertaken to determine temporal roles of individual complement activation products.

Objectives/Goals: Short-chain fatty acids (SCFAs) exert protective effects against calcium oxalate (CaOx) urinary stone formation in experimental rodent models, yet these effects are not understood in natural stone formers. This study will define the impact of SCFAs on stone risk factors along the gut–kidney axis in a natural canine model of CaOx stone disease. Methods/Study Population: A randomized, placebo-controlled, clinical trial will be performed using a crossover study design. Twenty dogs that are natural CaOx stone formers will be fed a standardized diet and randomized to receive either a daily prebiotic fiber (inulin) that stimulates SCFA production or a placebo. We will perform fecal shotgun metagenomics and SCFA quantification before and after each intervention (four timepoints) to identify how inulin and SCFAs enrich or deplete pathways relevant to stone formation within the gut microbiome. RT-qPCR will be performed to determine the effects of SCFAs on intestinal oxalate transporter gene expression (SLC26A3 and SLC26A6). At each timepoint, urinary shotgun metagenomics and quantification of urine biochemical profiles used to predict stone risk will also be performed. Results/Anticipated Results: We anticipate that prebiotic stimulation of SCFAs with inulin will reduce stone risk factors along the gut–urinary axis in a natural canine model of urinary stone disease. Specifically, we anticipate that prebiotic stimulation of SCFAs will 1) modify gut and urinary microbial communities to promote pathways considered protective against stone formation, 2) alter the expression of oxalate transporters (SLC26A3, SLC26A6) to reduce net oxalate absorption, and 3) reduce stone-promoting metabolites (e.g., oxalate) in the urine. Discussion/Significance of Impact: By defining the impact of prebiotic fibers and SCFAs on the gut–urinary axis in a natural animal model of CaOx urolithiasis, we will lay the foundation for novel nutritional strategies to prevent CaOx stone disease in both humans and animals.

Objectives/Goals: The bromodomain PHD finger transcription factor (BPTF) is an oncogenic driver of neuroblastoma. Our objective is to pioneer the discovery of the first class of chemical compounds that engage the PHD finger of BPTF and inhibit its biological function in cellulo, thereby establishing first-in-class chemical probes for this epigenetic reader. Methods/Study Population: Our previous work has identified a collection of small molecules that engage BPTF PHD in vitro. Following structure–activity relationships analysis, candidates will be used in a neuroblastoma cell model to validate BPTF PHD interaction in cellulo and predict therapeutic potential. Nanoluciferase bioluminescence resonance energy transfer (NanoBRET) will be used to confirm BPTF PHD engagement by compounds. Selective toxicity in neuroblastoma cells upon inhibitor treatment will be gauged by comparing cell growth and viability in the IMR-32 cell line against the HEK293 cell line. Treated HEK293 cells will be subjected to the assay for transposase-accessible chromatin (ATAC) and RNA sequencing methods to monitor changes in chromatin structure and transcriptional signatures against untreated cells. Results/Anticipated Results: We hypothesize that compounds with low micromolar potency for BPTF PHD in vitro will engage the target in cellulo and displace NanoLuciferase tagged protein from its HaloTagged® peptide binding partner. Additionally, we anticipate that our inhibitors will show cytotoxicity for IMR-32 cells with limited effects on HEK293 cells. We envision that inhibitor treatment in HEK293 cells will correlate with reduced chromatin exposure, suggesting that blocking the BPTF–histone interaction via PHD finger inhibition hinders the remodeling of transcriptionally silent heterochromatin into a transcriptionally active state. Finally, we expect that inhibitor treatment will result in diminished gene expression of oncogenic transcription factors, including N-Myc, a biomarker of neuroblastoma. Discussion/Significance of Impact: These first-in-class chemical probes for BPTF PHD will enable further investigation of BPTF and high-risk neuroblastoma progression, as well as its role in other diseases. In addition, these compounds will serve as a platform for the development of new anticancer agents that may improve outcomes for children that suffer from high-risk neuroblastoma.

Objectives/Goals: Congenital cytomegalovirus (cCMV) continues to be the primary infectious cause of fetal anomalies. The role of fetal natural killer (NK) cells in response to cCMV remains largely unexplored. This study seeks to investigate how fetal NK cells respond to human cytomegalovirus (HCMV) during gestation. Methods/Study Population: Umbilical cord blood and corresponding umbilical cord tissues were collected from fetuses that had no complications during gestation. These samples, provided by the Medical College of Wisconsin Tissue Bank, were processed within 24 hours after live birth. Single-cell suspensions were prepared from the samples, and fetal NK cells were isolated and exposed to HCMV antigen peptides VMAPRTLFL, VMAPRTLIL, VMAPQSLLL, and the human self-peptide ALALVRMLI. These peptides were presented on HLA-E*01:03 BV421-conjugated tetramers produced by the National Institutes of Health Tetramer Core Facility. Additionally, fetal NK cells were also prepared for single-cell RNA sequencing (scRNA-seq), and cells were filtered and clustered based on the number of uniquely expressed genes. Results/Anticipated Results: Through unbiased clustering, our scRNA-seq analysis identified five unique fetal NK cell subsets in umbilical cord blood and four in the corresponding umbilical cord tissue. Notably, fetal NK cells exposed to HCMV during gestation were primarily mature NK cell subsets, while those from unexposed fetuses were mostly immature subsets. Additionally, HCMV-exposed fetal NK cells exhibited a strong recall response to the HCMV antigen, with a notably higher frequency and elevated production of IFN-γ. Conversely, naïve fetal NK cells from fetuses unexposed to HCMV produced significantly lower levels of IFN-γ. Finally, we identified a distinct subset of fetal NK cells that emerge following exposure to the HCMV antigen. Discussion/Significance of Impact: In this study, we show that HCMV infection can influence the formation of specific NK cell subsets and re-exposure to the HCMV antigen can trigger a recall response. These insights could pave the way for the development of innovative NK cell-based immunotherapies aimed at preventing fetuses from developing symptomatic cCMV.