Background: Indole-3-propionic acid (IPA), a gut microbiota-derived tryptophan metabolite, is associated with reduced cardiovascular disease risk. A recent clinical study identified an inverse correlation between circulating IPA levels and abdominal aortic aneurysm (AAA) incidence, and mouse models confirmed the protective effect of IPA. However, the underlying cell type-specific mechanisms remain unclear.    Methods: We performed single nuclei RNA sequencing (snRNAseq) on suprarenal aortas from AngII-infused ApoE-/- mice fed control or IPA-supplemented diets to assess how IPA impacts vascular cells in AAA. We characterized transcriptional changes across vascular cell types and performed differential gene expression and pathway enrichment analyses. The effect of IPA on apoptosis was validated in cultured vascular smooth muscle cells (vSMCs) using TUNEL assays, which detect DNA fragmentation as a marker of programmed cell death.    Results: snRNAseq revealed that IPA remodeled the vSMC transcriptome, including emergence of a distinct subcluster enriched for genes involved in extracellular matrix remodeling and negative regulation of vSMC apoptosis. TUNEL assays confirmed that IPA reduced AngII-induced apoptosis in cultured vSMCs. These findings support a protective role for IPA through stabilization of vSMC populations.    Conclusions: Our results reveal that IPA mitigates AAA progression by attenuating vSMC apoptosis. These findings offer novel insight into cell type-specific mechanisms underlying the protective effects of IPA and support its potential as a non-invasive therapeutic for AAA. Future studies should investigate the apoptotic signaling pathways in vSMCs that are modulated by IPA.

Mitochondria are dynamic organelles pivotal for cellular energy production, metabolic regulation, and immune signaling. To ensure these roles, mitochondria remodel their shape, distribution, and interaction with other organelles. We recently identified a novel mitochondria-derived structure dubbed structures positive for outer mitochondrial membrane (SPOTs) that arise during infection of protozoan parasite Toxoplasma gondii. SPOTs are large vesicular structures of outer mitochondrial membrane (OMM) and lack all other classical mitochondrial components. Over the course of infection, SPOTs engulf lysosomes and become acidified structures in the cytosol of infected cells. However, the purpose and underlying mechanism of SPOT-lysosome interaction remain unknown. Here, we aim to define the composition of SPOT-lysosome structures. To do so, we sought to isolate lysosomes under uninfected and infected conditions using dextran-coated magnetic nanoparticles. Following isolation, samples will be analyzed by immunoblotting and proteomics to profile SPOT-lysosomes. We expect to see different molecular components between cytosolic lysosomes and SPOT-engulfed lysosomes. Our findings demonstrate a previously undescribed mitochondria-lysosome interface during infection that may confer parasite growth advantages. 

Hepatocellular carcinoma (HCC) is an important global health problem. One challenge in treating HCC is its frequent diagnosis at advanced stages, which limits treatment options. Current treatments target the tumor microenvironment, focusing on angiogenesis and immune regulation, but the variability in patient response suggests a need to explore gene expression patterns for better treatment prediction. In this project, we asked whether tumor gene expression patterns can help predict which tumors benefit from blocking vascular endothelial growth factor (VEGF) receptor signaling. We used HCC cell lines and patient-derived xenograft (PDX) mouse models treated with cabozantinib( VEGF receptor inhibitor). Then, RNA-seq and qPCR were used to measure changes in angiogenesis-related genes, including VEGFA and CXCL8. Principal component analysis (PCA) and non-negative matrix factorization (NMF) revealed three distinct tumor clusters based on expression profiles, highlighting potential biomarkers for treatment response. Weighted gene co-expression network analysis (WGCNA) was used to identify CXCL8 and STAT3 as key genes associated with treatment response. The identification of key genes, along with the distinct expression clusters, suggests that variation in chemokine and angiogenic signaling may explain differences in sensitivity to anti-VEGF therapy.

Pain is a current leading concern in the U.S.A. impacting ~20% of Americans. Opioid pharmacotherapies available to patients do not effectively treat long term chronic pain states and could lead to misuse and substance use disorders. To improve pain treatment therapies, our lab aims at uncovering the neuronal networks underlying negative affective states accompanying pain experience. The nucleus accumbens (NAc), a central nervous brain structure involved in the integration of signals related to reward, motivation, aversion, and learning, plays a critical role in pain modulation. We previously demonstrated that within the NAc, dynorphin, an opioid neuropeptide, released by local dynorphin-containing neurons is necessary for the expression of negative affect during inflammatory pain. The goal of this study is to determine whether efferent projections from NAc dynorphin-containing neurons to the lateral hypothalamus (LH), a structure that plays a role in the modulation of sleep, mood, and appetite, are the primary drivers of pain-induced negative affect. To meet this goal, we used a combination of behavioral pharmacology, fiber photometry, and assessed motivation for sucrose rewards through the number of active pokes - an outcome significantly reduced during pain experience - for mice. Here we reveal that kappa opioid receptors (KORs) in the LH are necessary for driving pain-induced negative affect. Indeed, silencing their activity using a long term antagonist, norbinaltorphimine (NorBNI), prevented pain-induced decrease in motivation for sucrose. This study provides evidence for targeting KORs to improve pharmacotherapies aiming to alleviate negative outcomes during pain.

Beyond their role as the powerhouse of the cell, mitochondria are also considered key regulators of cellular functions, such as cell differentiation. However, their role in neuronal differentiation remains largely under-explored. To investigate this, we cultured D17 neurons in vitro and performed stable isotope tracing using uniformly labeled 13C-glucose. We aimed to study the neurons under both basal conditions and in response to a compound that metabolically challenged the neurons. Gas chromatography-mass spectrometry (GC-MS) was then used to quantify enrichment of the 13C tracer into glycolytic and TCA cycle metabolites. Preliminary analysis shows that mole percent enrichment (MPE) values tended to increase over time. GCMS analysis demonstrates how neurons change their glucose use or shift their energy pathways during development. We wanted to investigate the MPE of uniformly labeled glucose after neurons were metabolically stimulated with the voltage-gated sodium channel activator, veratridine. Veratridine exposure appeared to further increase MPE values in a dosage-dependent manner. This suggests that short-term changes in mitochondrial and glycolytic activity occurred in response to stimulation from veratridine treatment. This allowed us to trace metabolic flux with greater specificity and assess how different substrates contribute to mitochondrial metabolism during early differentiation. We then used additional stable isotope tracers, such as 3-13C-glucose with 1-13C-pyruvate, to further examine pathway-specific enrichment. Together, these results indicate that stable isotope tracing with GC-MS is a valuable tool to study how neuronal metabolism shifts during differentiation and in response to external signals. Ongoing work will include broader metabolite analysis and integration with assays to define how mitochondrial activity contributes to neuronal development.

Previous work has found that preschool-age children tend to prefer novelty over certainty, while younger toddlers tend to prefer more predictable outcomes.  We seek to further this work by understanding whether two-year-olds’ preference for certainty can be affected by personal agency. We hypothesize that the preference for certainty in children at the age of two will strengthen when given personal agency. To accomplish this, we gathered data from n = 111 children, randomly splitting them into two groups: experimenter or child agency. The experiment consisted of a game in which either the participant or the experimenter pressed buttons to activate two machines. One machine had a certain outcome, creating the same block each time, while the other machine had an uncertain outcome, creating a different shape block each time. After seeing the outcomes of both machines, the participant was asked to choose which of the two machines they wanted to see one more time, and their decision showed their preference for either the certain or uncertain outcome. We expect results to show an association between agency and preference for certainty in two year old children. Data collection is still ongoing, but results so far demonstrate a trend towards preferring novelty when given personal agency, which goes against our original hypothesis. Future directions involve expanding this study to older children with the agency factor to see if novelty preference changes, or finding any possible applications to educational practices regarding child agency.