Objectives/Goals: We have shown that parathyroid hormone-related protein (PTHrP) is enriched at the LIFR promoter in breast cancer cells and inhibits the expression of dormancy-associated genes including LIFR. The objective of this study is to define where all PTHrP binds DNA and identify pathways that are regulated by PTHrP that promote breast cancer colonization of the bone. Methods/Study Population: In this study, we use human estrogen receptor-positive MCF7 breast cancer cells which we and others have reported lie dormant in the bone. MCF7 cells were engineered to express either PTHrP with an HA-tag (MCF7P), or a vector control (MCF7V). We use Cleavage Under Targets and Release Using Nuclease (CUT&RUN), a method of mapping protein-DNA interactions, to define where PTHrP binds DNA. Here, an HA-specific antibody identifies regions of DNA that are bound to PTHrP in MCF7P cells compared to MCFV cells. Next, we perform DNA sequencing and gene set enrichment analysis (GSEA) on genes identified by CUT&RUN to identify pathways that are regulated by PTHrP. These experiments will determine how PTHrP regulates dormancy and breast cancer colonization in the bone. Results/Anticipated Results: We completed IgG (-control), H3K4me3 (+ control), and HA (PTHrP) CUT&RUN on MCF7V and MCF7P cells, and submitted DNA for sequencing. This study will define where PTHrP binds the genome and identify pathways regulated by PTHrP. Previously, through ChIP-qPCR we showed that PTHrP binds the LIFR promoter to repress LIFR expression. Given this result, we expect that PTHrP binds to the promoters of dormancy-associated genes including LIFR in MCF7P cells compared to MCF7V cells. PTHrP may be involved in regulating other processes besides dormancy to induce expansion of breast cancer cells in the bone, so we will use GSEA to identify pathways that are altered in MCF7P cells when PTHrP is over-expressed compared to MCF7V cells. Together, this will define how PTHrP regulates gene expression of bone metastatic breast cancer cells. Discussion/Significance of Impact: This study will unveil mechanisms of metastatic breast cancer expansion in the bone by defining where PTHrP binds the genome to regulate gene expression. These findings will reveal therapeutic vulnerabilities that will be used to target bone-disseminated tumor cells to prevent lethal recurrence.

Objectives/Goals: To use patient-level Center for Medicare and Medicaid Services (CMS) mandated quality metrics for inpatient rehabilitation facilities (IRFs) to develop and validate predictive models of functional recovery and interactions of baseline characteristics with therapy time. Methods/Study Population: Retrospective cohort study of a national US sample of ~40,000 adults with a primary diagnosis of stroke admitted to IRFs in 2023. Records will be randomly allocated to equal training and validation samples. We will use a random forest approach to generate predictive models for self-care and mobility functional outcomes using patient baseline and demographic data from a CMS-mandated assessment for IRFs (Section GG). We will also examine how predictive variables modulate the effects of occupational, physical, and speech-language therapy minutes. The random forest is a machine-learning approach that trains multiple models and combines their predictions to improve their overall performance. Results/Anticipated Results: Predictive models developed from the training sample will be applied to the validation sample to confirm their capacity to support new observations. Preliminary results will be reported, including the F1 score and area under the curve (AUC), with 95% confidence intervals. A unique feature of this study is the large sample, which contrasts with prior research in stroke rehabilitation using machine learning approaches. This study will produce powerful models that will inform the design of a clinical decision-support tool for application into clinical practice in a future study. Discussion/Significance of Impact: By using CMS-mandated quality metrics that are collected as part of standard clinical practice in IRFs, results will support clinical interpretation and application of metrics and inform the development of a clinician-facing intervention to support personalized rehabilitation approaches.

Objectives/Goals: Our aim is to compare scores collected from a health utilities measure (Health Utility Index, HUI) to those collected from a profile measure (Child Health Ratings Inventories, CHRIs- Global) among youth with newly diagnosed, high-risk classic Hodgkin lymphoma. Methods/Study Population: We will analyze existing data collected during the Children’s Oncology Group AHOD 1331 trial, which was a phase 3 clinical trial comparing the efficacy of adding brentuximab vedotin to standard-of-care treatment with multiagent chemotherapy in children and adolescents with high-risk Hodgkin lymphoma. The study also had a prespecified patient-reported outcomes (PRO) secondary aim, which involved recruiting a subset of the initial 309 patients aged 11 years or older enrolled in the trial for serial PRO measures taken over the trial period. Health-related quality of life (HRQoL) was assessed by CHRIs, HUI version 2, and HUI version 3 assessments at six planned points throughout treatment. Results/Anticipated Results: The first step of our analysis will be to ascertain agreement in scoring for parent–child dyads for the HUI2, HUI3, and CHRIs scores by comparing mean scores via two-sample t-testing. Bland–Altman plots will be constructed to compare agreement between the scores for HUI2/3 and the CHRIs. Similarly, Spearman’s correlation coefficients will be calculated for CHRIs with HUI2/3 for both parents and children. We hypothesize the CHRIs and HUI scores should roughly correlate with one another, but there may be divergence of correlation because the HUI has greater emphasis on functionality (e.g., sensation, mobility), and the CHRIs further emphasize social and emotional well-being in addition to physical health. Discussion/Significance of Impact: The composite score of the HUI 2/3 has allowed for direct comparison with other global HRQoL measures, providing greater clarity of its performance in different patient populations and clinical settings. The current study will improve understanding of the HUI 2/3 performance in a pediatric cancer population over time.

Objectives/Goals: Accurately stratifying patients with clinically isolated syndrome by risk of developing multiple sclerosis is of great clinical importance. Though numerous prediction models attempt to achieve this goal, no systematic review exists to independently evaluate these models. We aim to systematically identify and assess the risk of bias in all such models. Methods/Study Population: Studies developing or validating prediction models to assess risk of developing MS in patients with CIS who are not receiving an MS-indicated disease-modifying therapeutic will be identified via a systematic literature search. Studies will be evaluated for overall risk of bias using PROBAST (Prediction model Risk Of Bias Assessment Tool). Briefly, data sources, predictor, and outcome definition and assessment, applicability, and analysis will be assessed for each model in each identified study, and an overall risk of biased judgment will be assigned. Identified studies, predictors incorporated, results, and risk of bias assessment with accompanying rationale will be summarized in the final report. Results/Anticipated Results: Based on an initial exploratory search, we anticipate that most, if not all, identified prediction models will have high risk of bias. We anticipate that many studies will have limited applicability due to the use of outdated diagnostic criteria for definition of outcomes, or high risk of bias concerns originating from their analysis due to insufficient volume of included participants or poor model validation practices. We further anticipate that most, if not all, of the identified prediction models will have limited potential to be translated to use in a clinical setting. Discussion/Significance of Impact: Understanding how to identify patients with high-risk CIS may inform and improve clinician treatment decisions, patient outcomes, and future research study design. This work may also reveal flaws in current prediction models for CIS, opening new avenues of research and prompting development of improved prognostic models for patients with CIS.

Objectives/Goals: The goal of this project was to engineer 3D lung models by embedding human epithelial cells and fibroblasts within hybrid-hydrogels containing human decellularized extracellular matrix (dECM) from healthy and fibrotic lungs. This platform will enable us to study cell–matrix interactions involved lung fibrosis pathogenesis. Methods/Study Population: To incorporate dECM into hybrid-hydrogels it must be digested and functionalized. We determined the best conditions for pepsin digesting dECM from healthy and fibrotic human lung by collecting samples every 12 hours up to 96 hours and measuring total protein (BCA assay), total amine concentration (ninhydrin assay), and protein fragment size (SDS PAGE). Next, several molar excesses of Traut’s reagent were tested and functionalization was verified by comparing amine content (ninhydrin assay) to thiol content (Ellman’s assay). Hydrogel stiffness was measured initially and after stiffening using parallel-plate rheology. Results/Anticipated Results: The dECM was successfully pepsin-digested, with the 48-hour time point yielding the highest free amine levels. A 75-molar excess of Traut’s reagent was best for converting free amines to thiols. Dynamic stiffening allowed the creation of hybrid-hydrogels mimicking both healthy (1–5 kPa) and fibrotic (>10 kPa) lung microenvironments. We anticipate that this model will demonstrate differential fibroblast activation based on hybrid-hydrogel dECM source (healthy or fibrotic), microenvironmental stiffness, and cell source (healthy or fibrotic). Validation of this 3D co-culture system could accelerate drug discovery by providing a more accurate in vitro platform for high-throughput screening. Discussion/Significance of Impact: This work advances pulmonary fibrosis modeling by creating human dECM-based hydrogels that recapitulate the cellular and mechanical microenvironment of healthy and diseased lung, potentially enabling us to uncover novel therapeutic targets and improving drug efficacy testing in vitro.

Objectives/Goals: This study tests how fiber microstructural integrity and myelination levels within the cingulum connectome are associated with information processing speed (IPS) in relapsing-remitting multiple sclerosis (RRMS). We investigate the functional impact of structural coherence, myelin content, and white matter hyperintensities (WMH) load on IPS. Methods/Study Population: Data from 63 RRMS and 25 healthy controls (HC) were used. We hypothesize that the structural integrity of the cingulum bundle and its structural network – or connectome – is distinctly associated with IPS function in people with RRMS (vs. HC) due to myelin-related plasticity across the wiring. Using diffusion spectrum imaging and high-resolution tract segmentation, we constructed individualized white matter connectomes. Diffusion quantitative anisotropy (QA) and myelin fractions (MWF) were used to quantify structural coherence and myelination. WMH load was measured with T2-FLAIR imaging. Bayesian–Pearson correlations, mixed-linear, and moderation models explored how fiber-specific QA, MWF, and WMH load relate to IPS function in RRMS, as measured by Symbol Digit Modalities Test (SDMT). Results/Anticipated Results: We theorize that (1) QA in the cingulum connectome correlates with SDMT performance dimensionally, indicating that structural coherence in the white matter supports IPS function among both groups; (2) increased myelination will strengthen the positive association between QA and SDMT scores, suggesting that connectome-specific myelin content facilitates IPS; (3) conversely, WMH load within the cingulum connectome is expected to inversely correlate with SDMT scores, reflecting the detrimental impact of lesion burden on IPS function; (4) myelination in specialized tracts within the cingulum connectome play a compensatory role to support IPS function in the RRMS group. These investigations can offer a mechanistic clue to potential neuroplastic targets for cognitive interventions in MS. Discussion/Significance of Impact: By linking white matter integrity to cognitive function at the connectome level, this study can support neuroregenerative strategies to mitigate cognitive burden in RRMS. Our findings may advance understanding of how structural coherence, tract myelination, and WMH affect IPS, shaping personalized prognostic and therapeutic interventions.

Objectives/Goals: Obesity has been classified as a global epidemic and origin of numerous health issues. The central hypothesis of this study is that psychological measures, DNA methylation, and gene transcription will predict obesity-related outcomes after lifestyle interventions, and such interventions may alter DNA methylation profiles. Methods/Study Population: This study consisted of a randomized-controlled trial examining the effects of lifestyle +/- stress reduction interventions in 285 highly stressed parents with obesity, followed for 2 years. Full participants received nutrition and activity counseling, and were randomized to either a stress reduction intervention or a contact control. Those who otherwise qualified for the study but unable to fully participate were included in a no intervention control group. The intervention consisted of 12 weeks of nutrition and activity counseling +/- 2-hour weekly stress reduction interventions using MBSR and CBT-based strategies. DNA methylation was assessed using Illumina EPIC arrays. Results/Anticipated Results: Using linear mixed models (LMMs), this study will first examine the hypothesis that baseline psychological measures and pre-existing methylation sites associated with obesity and glycemic control (e.g., ABCG1, ATP10A, TXNIP, SREBF1, RNF39, and SOCS3) predict changes in BMI, HOMA-IR, and HgbA1C post-intervention and at 1 and 2 year follow-ups. Using sites that demonstrate statistical significance, we will develop a polymethylation risk score predictor of change in BMI. Next, we will examine the hypothesis that interventions which reduce obesity may also lead to improvements in epigenetic aging using LMMs to determine if changes in BMI or HOMA-IR predict changes in epigenetic age acceleration over the course of the study. Discussion/Significance of Impact: This work examines whether psychological factors and/or epigenetic markers may be used in patient stratification at initiation of treatment, enabling improved treatment selection, fewer years of obesity and decreased risk of comorbidities. This proposal also asks whether lifestyle interventions impact the aging process itself.

Objectives/Goals: Our team has developed a 24-well donor-derived skeletal muscle microphysiological system (MPS) to study signaling pathways associated with a variety of muscle diseases. 3D muscle will be utilized to evaluate pharmacologic interventions for these muscle conditions to improve both muscle mass and function. Methods/Study Population: In this study, muscle MPS were formed from healthy young female and male subjects. 3D muscle underwent a 21-day differentiation with an electrical stimulation (e-stim) regimen twice daily beginning on Day 14. Functional assessments in permeabilized fibers of both sexes included isometric and isotonic calcium-induced contractions, allowing for the characterization of force-pCa (-log[Ca2+]), force-velocity and force-power relationships. Samples from Day 17 and Day 21 will be assessed for pro-growth protein signaling via western blotting and a subset of samples will be analyzed by histology and microscopy for fiber type and size. Finally, culture media pre- and post-terminal e-stim on Day 21 will be collected for extracellular vesicle (EV) isolation and EVs will be assessed by standard proteomics analysis. Results/Anticipated Results: Permeabilized fibers from both sexes reproduced the well-established sigmoidal force-pCa and the curvilinear force-velocity and force-power relationships reported in native striated muscle. Maximum specific force and force-pCa relationship were not different between sexes. Isotonic contractile measurements revealed that these male and female fibers also exhibit similar force-velocity and force-power relationships. We anticipate that 3D muscles from day 17 compared to day 21 will exhibit higher levels of pro-growth protein signaling due to e-stim application and no differences in fiber type or size between sexes. Additionally, we expect that EV quantity will depend upon 3D muscle maturity and presence of e-stim. Discussion/Significance of Impact: This study demonstrates the similarities of functional characteristics and exercise (or e-stim) adaptation between native human skeletal muscle and 3D bioengineered skeletal muscle. Ultimately, this data further validates the muscle MPS system to study muscle diseases and to enhance the translation of therapeutics to clinical settings.

Objectives/Goals: This review examined if sleep duration is associated with established Alzheimer’s disease (AD) fluid biomarkers, such as amyloid-β peptides (Aβ40 and Aβ42), total-tau (t-tau), phosphorylated tau (p-tau181 and p-tau217), neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP). Methods/Study Population: We searched PubMed, CINAHL, and SCOPUS through September 15, 2024, using keywords and appropriate subject headings related to AD, fluid biomarkers, and sleep. The search was developed and conducted in collaboration with a medical librarian. We also searched Google Scholar and screened the reference lists of relevant reviews. Two independent reviewers screened 1,657 peer-reviewed articles, of which 21 met the inclusion criteria (14 with biomarkers measured in cerebrospinal fluid [CSF] and 7 in blood). Two review authors independently extracted study details from included articles using a standardized data extraction template. Results/Anticipated Results: Sample sizes ranged from 18 to 4,712 participants. Sleep duration was assessed using self-reported measures in 8 studies and objective measures in 13. For the 14 studies using CSF biomarkers, lower Aβ42 (3/14), Aβ40 (1/14), or the ratio (1/14) were associated with either short or long sleep duration; t-tau (3/14) and p-tau181 (4/14) levels were mostly associated with short sleep. For the 7 blood-based biomarker studies, Aβ42 (2/7), Aβ40 (2/7), and the ratio (3/7) had mixed results with either short or long sleep. T-tau (1/7) and p-tau181 (1/7) levels were associated with long sleep; NfL (2/7) was associated with both short and long sleep. Six studies reported nonlinear relationships, with both short and long sleep associated with unfavorable biomarker profiles. None of the studies investigated p-tau 217 or GFAP. Discussion/Significance of Impact: Our results suggest that the relationship between sleep duration and AD fluid biomarkers is very complex, and it highlights the importance of sleep in AD risk assessment and prevention. The inconsistency in findings stresses the need for standardized study design and measurement methods to clarify causality and inform clinical guidelines.

Objectives/Goals: Neuromodulation strategies like transcranial magnetic stimulation (TMS) can target specific neural circuits underlying particular psychiatric symptoms, potentially 1) enhancing understanding of mechanisms of illness and recovery and 2) acting as novel therapeutics. These feasibility studies lay foundation for a study of major depression. Methods/Study Population: Four healthy volunteers completed structural and functional MRI (fMRI). fMRI included a trait-adjective task, a negative self-referential processing task known to activate VMPFC, which is known to be abnormal in major depression. During the task, participants respond on a task pad whether they feel that each of a series of displayed adjectives (positive, negative, or neutral) applies to them. Three participants then participated in a simulated image-guided TMS session using their MRI data to target their VMPFC. Three-dimensional tracking of the participant’s head and the TMS coil was used to position the coil for peak stimulation of the targeted brain region. Results/Anticipated Results: Our team collected quality neural and behavioral data on the fMRI task; participants reported a tolerable experience. Simulated neuronavigated TMS showed feasibility and tolerability of positioning the device to stimulate VMPFC. The fMRI task activated the VMPFC as predicted. The MRI and TMS protocols were replicable and tolerable. These procedures can now be used experimentally by our team with confidence to test our hypothesis that targeting the VMPFC within the brain’s default-mode network may normalize aberrant VMPFC activity seen in major depression, thereby improving excessive negative self-referential processing. Discussion/Significance of Impact: This project lays essential groundwork for my K12 project, “Targeting Negative-Self Referential Processing in Depression with TMS,” a longitudinal neuroimaging and behavioral study using these methods in the study population of people with major depression.

Objectives/Goals: Increased follicle-stimulating hormone (FSH) is linked to declines in ovarian and metabolic function in older women. Obesity is both a manifestation and a driver of aging pathologies. In animal models, FSH and insulin resistance (IR) were reduced after 6 mos. of a nutritional therapeutic (GLYLO). Our goal was to translate preclinical evidence to humans. Methods/Study Population: An integrated, precision medicine approach identified a unique phenotype of aging-related debility relative to older females. A non-comparer pilot study was conducted to translate GLYLO preclinical findings to postmenopausal women with obesity (n = 85; >55 years; body mass index [BMI]  = 35.0±4.35; range: 30.3–42.8). Participants meeting the inclusion and exclusion criteria (n = 13) were enrolled and received two capsules of GLYLO (vitamins and natural products) daily for 6 mos. Assessments for FSH, estradiol (E2), IR (homeostatic model [HOMA-IR]), total cholesterol (TC), low- (LDL), high-density lipoproteins (HDL), safety biomarkers (e.g., red cell distribution width [RDW%], mean corpuscular volume [MCV]), and depression (Center for Epidemiologic Studies Depression Scale) were conducted prior to and after 6 mos. Results/Anticipated Results: Mixed-effect models with intent-to-treat analysis were applied to compare outcomes prior to (n = 13) and following (n = 7) the intervention. Significant reductions in FSH were observed (-13.1 [2.47] ∆/SD; p = 0.002)) following the 6-month intervention. Interestingly, BMI, E2 (p = 0.412), HOMA-IR (p = 0.885), TC (p = 0.363), and LDL (p = 0.145) were unchanged, while HDL decreased significantly (-9.7 [3.82] ∆/SD; p = 0.044). Other biomarkers, RDW% (-0.2 [0.05] ∆/SD; p = 0.009) and MCV (-2.3 [0.33] ∆/SD; p = 0004), were significantly reduced. All other safety parameters were not altered. Six participants reported mild to moderate adverse events (acid indigestion) and were lost to follow-up. Depression scores significantly increased (+4.0 [0.75] ∆/SD; p = 0.002)). Results were similar with and without intent to treat analysis. Discussion/Significance of Impact: Decreased FSH, but not IR, was observed following six months of GLYLO in postmenopausal women with obesity. Significant alterations in HDL, depression, RDW%, and MCV warrant further investigation. Findings are limited by the small sample size and loss to follow-up. Randomized, controlled trials are needed to confirm these results.

Objectives/Goals: Large-scale tumor sequencing efforts have led to annotations of novel cancer hotspot mutations that may underlie driver or cooperative function. We have sought to define the molecular consequences of such hotspots associated with pediatric DICER1 syndrome cancers, with the ultimate goal of revealing novel targets that may inform new standards of care. Methods/Study Population: We have performed genomic analysis to identify tumor types (in TCGA and MSK-IMPACT patient data) for which mutations in the Dicer1 gene (encoding Dicer protein) emerge as the dominant signature of driver function. As Dicer is a critical RNA processing factor responsible for the generation of microRNAs, which are posttranscriptional gene regulatory molecules, we have modeled these mutations in human embryonic stem cells in order to study the direct effects on miRNAs and their target genes in an isogenic background. In addition to providing the required setting for unambiguous attribution of function to specific mutations, clonal human ES cells offer an opportunity for modeling of both developmental and cancer requirements associated with altered Dicer function. Results/Anticipated Results: Through generation of genomics and functional datasets from matched genotypes in Dicer mutated human ES cells, we have identified specific alterations in miRNAs and their effects on target genes. Unexpectedly, we found direct evidence for both loss of function and gain of function attributable to Dicer mutations. In addition, through integrated analysis of genomic data from tumor sequencing datasets and our human ES cell models, we have identified potential miRNA and target gene alterations that underlie tumorigenic potential, nominating gene candidates for targeted therapy in DICER1 syndrome. Direct mouse modeling of such candidate gene targets has revealed evidence for driver function of identified miRNA and their targets. Discussion/Significance of Impact: DICER1 syndrome cancers comprise a wide variety of rare pediatric tumor types. Presently, we still lack an effective standard of care. Furthermore, the previous lack of molecular profiling precluded targeted therapy opportunities. Our precise knock-in modeling of Dicer hotspots and deep profiling of relevant tumors now provide candidate targets.

Objectives/Goals: Cutaneous lupus erythematosus (CLE) is an inflammatory skin manifestation of lupus. CLE lesions are frequently colonized by Staphylococcus aureus, a microbe known to promote IFN production and inflammation. Here, we investigate whether type I IFN and inflammatory gene signatures in CLE lesions can be modulated with a topical antibiotic treatment. Methods/Study Population: SLE patients with active CLE lesions (n = 12) were recruited and randomized into a week of topical treatment with either 2% mupirocin or petroleum jelly vehicle. Paired samples were collected before and after 7 days of treatment to assess microbial lesional skin responses. Microbial samples from nares and lesional skin were used to determine baseline and posttreatment Staphylococcus abundance and microbial community profiles by 16S rRNA gene sequencing. Inflammatory responses were evaluated by bulk RNA sequencing of lesional skin biopsies. Immunophenotyping of CLE lesions was performed using CIBERSORTx to deconvolute the RNA-seq data into predicted cell populations impacted by treatment. Results/Anticipated Results: We identified 173 differentially expressed genes in CLE lesions after topical mupirocin treatment. Mupirocin treatment decreased the abundance of Staphylococcus associated with CLE lesions without altering the overall diversity of the skin microbiota relative to vehicle. Decreased lesional Staphylococcus burden correlated with decreased IFN pathway signaling and inflammatory gene expression and increased barrier dysfunction. Interestingly, mupirocin treatment lowered skin monocyte levels, and this mupirocin-associated depletion of monocytes correlated with decreased inflammatory gene expression. Discussion/Significance of Impact: Mupirocin treatment decreased lesional Staphylococcus burden and this correlated with decreased IFN signaling and inflammatory gene expression. This study suggests a topical antibiotic could be employed to decrease lupus skin inflammation and type I IFN responses by reducing Staphylococcus colonization.

Objectives/Goals: Our main objective was to compare 5-year survival and organ function between patients with sickle cell disease (SCD) who underwent hematopoietic cell transplant (HCT) and those who did not undergo HCT. We hypothesized that organ function would be improved in those with SCD who underwent HCT when compared to those who remained on standard therapy. Methods/Study Population: This IRB-approved, retrospective study includes patients with SCD treated at Children’s Healthcare of Atlanta. Cases underwent HCT between 2010 and 2016. They were randomly matched with 2 patients with SCD who did not undergo HCT. Match criteria included age, sex, disease genotype, and disease severity, which was determined by the number of hospitalizations in the 5 years pre-HCT, prior intensive care unit admission, and prior chronic transfusion therapy. Data extracted included SCD treatment, hospitalizations, emergency department visits, and organ function pre-HCT and 1-, 2-, 3-, and 5-years post-HCT. Organ-specific outcomes and overall survival were compared between the two groups using cumulative incidence curves and Kaplan–Meier analyses. Normal FEV1 and FVC in this analysis were >80% predicted. Results/Anticipated Results: Thirty-seven cases who had undergone HCT were matched with 74 controls who continued with standard medical therapy. The median age was 8 years for both groups and 59% were females. The median disease severity score was 2 in both groups. At baseline, 70.3% of the HCT group completed pulmonary function tests (PFTs) compared to 35.1% of the non-HCT group. Of these, 73% in both groups had a normal FEV1. In terms of FVC, 57.7% of HCT patients and 76.9% of non-HCT patients had a normal FVC pre-HCT. At 5 years post-HCT, 56.8% of the HCT group had PFTs completed compared to 21.6% of the non-HCT group. Among these, 85.7% in the HCT group had a normal FEV1 compared to 75% in the non-HCT group, while 90.6% had a normal FVC in the HCT group compared to 75% in the non-HCT group. Two of 37 in the HCT group and 1 of 74 in the non-HCT group died (p = 0.21). Discussion/Significance of Impact: Our data suggest that post-HCT, the proportion of patients falling in the normal range for FEV1 and FVC increases. This increase is not seen in the non-HCT group, indicating that HCT may improve this organ function. There was no difference in survival between the groups, indicating the risk of HCT mortality may not be greater than the risk of living with SCD.

Objectives/Goals: Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease with a mean survival of only 11 months even with the most advanced treatment to date. The desmoplastic microenvironment of PDA is thought to play a critical role in therapy resistance. One pathway that might be responsible for resistance to immunotherapy is the CXCR4-CXCL12 axis. Methods/Study Population: In this study, we propose to evaluate the effect of CXCR4-CXCL12 inhibition on dual checkpoint inhibition in KPC mouse model of PDAC and patient-derived explants. PDAC mouse models are made with pancreatic cancer cells driven by loss of TP53 and activation of KRAS. These models are treated with PD1 inhibitor Balstilimab and an FC-modified CTLA4 Botensilimab with or without CXCR4 inhibitor BL8040. In addition, we make explants of patient tumors along with their tumors and autologous peripheral blood mononuclear cells and this model is similarly challenged with BOT/BAL and BL8040. Using immunofluorescence and flow cytometry, we quantify and evaluate the spatial relationships between different cell populations. Most notably, we evaluate the relative abundance of CD8+ T cells in control and treated conditions. Results/Anticipated Results: We expect the inhibition of CXCR4-CXCL12 axis, along with two new potent checkpoint blockers, will lead to infiltration of CD8+ T cells in both the mouse and human PDAC models. We also expect this to translate into more tumor cell killing as demonstrated by Caspase activities and tumor shrinkage. Discussion/Significance of Impact: If our hypothesis is proven in both mouse and human PDAC models, this study will serve as a basis for a phase I/II clinical trial testing this combination of drug.

Objectives/Goals: As life expectancy increases in people with HIV, neurocognitive impairment is becoming more common, and women with HIV (WWH) are disproportionately impacted. This work investigated mitochondrial function and oxidative stress in WWH in order to understand the relationship between mitochondrial function and cognition in future studies. Methods/Study Population: Peripheral blood mononuclear cells were isolated from virally suppressed WWH (n = 64) and underwent the Seahorse Cell Mito Stress test to assess different realms of mitochondrial function. Cells were then lysed for direct DNA extraction, and quantitative PCR was performed to understand mitochondrial DNA expression (mtDNA) levels as a measure of oxidative stress. A series of simple linear regressions was then conducted to understand the relationships between mitochondrial function and mtDNA content. Future work will expand this analysis to investigate associations between demographic dynamics, such as trauma history, and mitochondrial function, as well as to understand the relationships between mitochondrial function and cognitive outcomes in WWH. Results/Anticipated Results: In our cross-sectional analysis of mitochondrial dynamics in WWH, we found a significant association between maximum mitochondrial respiration ability and mtDNA content, with greater mtDNA expression associated with increased levels of maximum respiration following stimulation. There was no association between basal respiration and levels of oxidative stress. There was also a significant variation in mitochondrial function in our participants, indicating that future analyses to investigate the source of that variation are warranted. The work presented here sheds light on mitochondrial dynamics in WWH and will be the basis for future studies that will investigate how demographic dynamics may be associated with mitochondrial function, as well as how mitochondrial dynamics may predict cognitive outcomes. Discussion/Significance of Impact: There is significant variation in mitochondrial function in WWH. More analysis is needed to understand what may be associated with these variations, including an investigation of both clinical factors as well as cognitive outcomes. This analysis will inform directions for future mechanistic work aimed at mitigating adverse cognitive outcomes in WWH.

Objectives/Goals: Hearing loss (HL) can result from environmental and genetic factors. Some genetic variants may be more prevalent in populations living in geographic or cultural isolation. This study explores the genetic variants associated with HL in Puerto Rico and correlates these with auditory and balance disorders to uncover novel variants. Methods/Study Population: After obtaining individual informed consent and assent for a minor when applicable, we will collect clinical audiological data and biological samples (n  =  600) from families across Puerto Rico with a history of severe to profound HL. Genomic DNA will be extracted, and exome and mitochondrial genome sequencing will be conducted to identify causal variants in genes associated with HL. The study will assess the prevalence of both novel and reported variants in genes associated with HL and investigate founder variants in the Puerto Rican population. Involvement of genes so far not associated with HL will also be considered when a genetic diagnosis cannot be established. Auditory phenotypes will be correlated with genetic findings, allowing for a comprehensive analysis of genetic contributions to HL in this population. Results/Anticipated Results: This research will advance understanding of the genetic causes of HL in Puerto Rico, leading to more accurate diagnoses, personalized treatment options, and the discovery of novel genes associated with HL. It will also serve as an evidence-based reference to analyze the adequacy of current neonatal hearing screening protocols in PR. Recruitment and sample collection have begun, and we expect our findings to uncover population-specific variants. These results will provide a foundation for further genetic studies aiming at identifying the causes of HL in Puerto Ricans regardless of age of onset. Discussion/Significance of Impact: This study will enhance our understanding of hereditary HL and serve as a basis for developing population-specific diagnostic tools and interventions, particularly in the Puerto Rican population. The research will support future genetic studies and address health disparities in HL in the island.

Objectives/Goals: Osteoarthritis (OA) is a multifactorial disease where sustained gut inflammation is a continued source of inflammatory mediators driving degenerative processes in joints. The goal was to use spontaneous equine model to compare fecal and leukocyte microbiome and correlation to transcriptome in OA. Methods/Study Population: Seventy-six horses (31 OA, 45 controls) were enrolled by population-based sampling. Feces and peripheral blood mononuclear cells (PBMC) were collected. Horses were determined to have OA by clinical and radiographic evidence. Horses were excluded if they received medications or joint injections within two months. Fecal and circulating leukocyte bacterial microbial 16s-seq was performed. Bulk RNAseq of PBMC was performed by the Illumina platform. Gene expression data were mapped to the equine genome, and differential expression analysis was performed with DESeq2. Qiime2 was used for microbial analysis. Enrichment analysis was performed with a cluster profiler. Correlation analyses were performed between the datasets. Results/Anticipated Results: Beta and alpha microbial diversity differed in feces and PBMC of OA vs. healthy horses. Horses with OA had an increased Firmicutes to Bacteroidetes ratio compared with controls. The fecal microbiome of OA horses had significantly higher amounts of Firmicutes Oribacterium (q Discussion/Significance of Impact: These data suggest that altered microbiome and PBMC gene expression are associated with naturally occurring OA in the translational equine model. While Oribacterium has been detected in humans with rheumatoid arthritis, its role in OA warrants further proteomic and metabolomic profiling.

Objectives/Goals: The study’s goal is to investigate the role of PPAR-α on regulating blood pressure, glomerular filtration rate (GFR), renal inflammation, and renal sodium reabsorption in mice on a 4% high-salt diet. Methods/Study Population: GFR, systolic blood pressure (SBP), inflammatory biomarkers (KIM-1, TIMP2, NGAL, MCP-1, TNF-α, IL-6, IL-10, and IL-17), and renal sodium transporter expression (NKA, NHE3, NKCC2, NCC, ENaC, Aqp-2, and NHERF1) were measured in PPAR-α KO mice and wild-type controls treated with a 4% high-salt (HS) diet. Male C57BL6, B129S1, and PPAR-α KO mice (12 weeks old) will be treated with 4% HS diet for 28 days. Systolic blood pressure is measured by tail cuff. GFR is measured by transdermal FITC-Inulin radioactive fluorescence. Inflammatory biomarkers will be measured by cytokine array and western blot. Sodium transporter expression will be measured by western blot. Results/Anticipated Results: Baseline SBP was 146 ± 31 mmHg (C57), 140 ± 24 mmHg (B129), and 153 ± 23 mmHg (KO). After 21 days of normal (control diet) or treatment (HS diet), control systolic pressures were 139 ± 18 mmHg (C57), 107 ± 23 mmHg (B129) and 147 ± 34 mmHg (KO), while HS systolic pressures were 166 ± 23 mmHg (C57) and 119 ± 34 mmHg (B129). We are collecting blood pressure for the KO HS group. Baseline GFR was 1194 ± 140 µL/min/g (C57), 1167 ± 279 µL/min/g (B129), and 1191 ± 157 µL/min/g (KO). Discussion/Significance of Impact: We hypothesize significantly higher SBP, inflammatory marker expression, and renal sodium transporter expression in KO and B129 mice on a HS diet. We predict that PPAR-α expression in the kidney will be higher in C57 compared to B129. We predict that PPAR-α activity plays a vital role in reducing high-salt-induced hypertension and inflammatory markers.

Objectives/Goals: This study aims to first understand the expression of the L-type amino acid transporter, Slc7a5, in demyelinated plaques in postmortem multiple sclerosis (MS) CNS tissue. It also seeks to understand the effect of a novel inhibitor of Slc7a5 on remyelination in mice with experimental autoimmune encephalomyelitis. Methods/Study Population: Using single-cell RNA sequencing (scRNA-seq), we will examine the expression of Slc7a5 in demyelinated plaques in postmortem CNS tissue of patients with MS compared to non-lesioned regions (n  =  3/group). Using visually evoked potential (VEP) on mice with experimental autoimmune encephalomyelitis (EAE), we will determine the ability of the Slc7a5 allosteric inhibitor OKY-034 to promote remyelination compared to EAE-only controls (n  =  10/group). Lastly, we will use spatial transcriptomics with scRNA-seq to map transcriptional activity within different populations of cells to determine how OKY-034 changes gene expression in specific cell types compared to EAE-only controls (n  =  3/group). Results/Anticipated Results: A conditional knockout of Slc7a5 showed that microglial activation and oligodendrocyte differentiation were affected in demyelinated lesions. This suggests that it plays a role in numerous cell types in active demyelinated plaques, which is what we expect to find from our scRNA-seq data in post-mortem CNS tissue of patients with MS. Measuring VEP is a noninvasive way to measure remyelination in both clinical and research settings. OKY-034 increases oligodendrocyte differentiation suggesting remyelination, so we expect that administration of OKY-034 in mice with EAE will lead to restored VEP compared to control and EAE-only mice. Lastly, because OKY-034 reduces inflammation, we expect to see a decrease in gene expression for genes involved in an immune response. Discussion/Significance of Impact: Completion of this study will lead to understanding what the effect the allosteric Slc7a5 inhibitor OKY-034 has on remyelination and whether it may serve as a novel therapeutic drug that can be administered orally for the treatment of MS. This could lead to its further development as a treatment for progressive MS.