Faculty Bibliography

Individuals with Down syndrome (DS) produce less saliva for unknown reasons resulting in chronic periodontal disease with systemic detrimental effects. Using the (Dp(16)1Yey) mouse model of DS we define the molecular mechanisms of hyposalivation and potential links to periodontal disease. We show that Dp(16)1Yey mice produce less saliva and have a higher immune burden in the salivary glands. We demonstrate that store operated calcium entry (SOCE), required for saliva secretion, is deficient in the salivary glands of Dp(16)1Yey mice. SOCE is also reduced in iPSCs from an individual with DS. We show that the oral and gut microbiomes of Dp(16)1Yey mice have abundant succinate-associated microbes and high succinate levels in the serum. We highlight associations between altered Ca²⁺ handling and hyposalivation, dysbiosis, and periodontal disease in DS. The administration of pilocarpine in Dp(16)1Yey mice increased salivation, suggesting that cholinergic agonists might be useful to improve the oral health of individual with DS.

Decreased brain levels of coenzyme Q₁₀ (CoQ₁₀), an endogenously synthesized lipophilic antioxidant^1,2, underpin encephalopathy in primary CoQ₁₀ deficiencies^3,4 and are associated with common neurodegenerative diseases and the ageing process^5,6. CoQ₁₀ supplementation does not increase CoQ₁₀ pools in the brain or in other tissues. The recent discovery of the mammalian CoQ₁₀ headgroup synthesis pathway, in which 4-hydroxyphenylpyruvate dioxygenase-like protein (HPDL) makes 4-hydroxymandelate (4-HMA) to synthesize the CoQ₁₀ headgroup precursor 4-hydroxybenzoate (4-HB)⁷, offers an opportunity to pharmacologically restore CoQ₁₀ synthesis and mechanistically treat CoQ₁₀ deficiencies. To test whether 4-HMA or 4-HB supplementation promotes CoQ₁₀ headgroup synthesis in vivo, here we administered 4-HMA and 4-HB to Hpdl^-/- mice, which model an ultra-rare, lethal mitochondrial encephalopathy in humans. Both 4-HMA and 4-HB were incorporated into CoQ₉ and CoQ₁₀ in the brains of Hpdl^-/- mice. Oral treatment of Hpdl^-/- pups with 4-HMA or 4-HB enabled 90-100% of Hpdl^-/- mice to live to adulthood. Furthermore, 4-HB treatment stabilized and improved the neurological symptoms of a patient with progressive spasticity due to biallelic HPDL variants. Our work shows that 4-HMA and 4-HB can modify the course of mitochondrial encephalopathy driven by HPDL variants and demonstrates that CoQ₁₀ headgroup intermediates can restore CoQ₁₀ synthesis in vivo.

Variations in the airway microbiome are associated with inflammatory responses in the lung and pulmonary disease outcomes. Regional changes in microbiome composition could have spatial effects on the metabolic environment, contributing to differences in the host response. Here, we profiled the respiratory microbiome (metagenome/metatranscriptome) and metabolome of a patient cohort, uncovering topographical differences in microbial function, which were further delineated using isotope probing in mice. In humans, the functional activity of taxa varied across the respiratory tract and correlated with immunomodulatory metabolites such as glutamic acid/glutamate and methionine. Common oral commensals, such as Prevotella, Streptococcus, and Veillonella, were more functionally active in the lower airways. Inoculating mice with these commensals led to regional increases in several metabolites, notably methionine and tyrosine. Isotope labeling validated the contribution of Prevotella melaninogenica in generating specific metabolites. This functional characterization of microbial communities reveals topographical changes in the lung metabolome and potential impacts on host responses.

INTRODUCTION/BACKGROUND:Secondhand exposure to e-cigarettes represents a potential population health risk given e-cigarette's prevalence and their unknown health effects, particularly among vulnerable populations such as pregnant people. OBJECTIVES/OBJECTIVE:To explore metabolomic differences between pregnant people exposed vs. not exposed to secondhand e-cigarette aeresols, to identify possible biomarkers of exposure and metabolic pathways perturbed by e-cigarettes. METHODS:Exposed participants (n = 19) from the NYU Children's Health and Environment Study were matched to unexposed participants (n = 57) at a 1:3 ratio on age, hospital of recruitment, and race/ethnicity. Early-pregnancy urine samples were analyzed via an untargeted metabolomics platform using reverse-phase liquid chromatography mass-spectrometry. Feature-exposure associations were estimated using conditional logistic regression to adjust for matching factors. A sensitivity analysis was conducted adjusting for secondhand tobacco exposure. RESULTS:Among features enriched in the exposed group were flavonoids and flavor-related compounds including homoeriodictyol and naringenin-7-O-beta-D-glucuronide, 3-acetomidocoumarin, and guaiacol pentosylglucoside; synthetic drugs such as the endocannabinoid AM1172 and the stimulant alpha-PVP; and metabolites associated with lipid metabolism, including 2,4-undecadiene-8,10-diynoic acid isobutylamide, palmitamide, glycerol trihexanoate, and tetradecyl phosphonate. Among features negatively associated with exposure were xanthines. CONCLUSION/CONCLUSIONS:This study is the first untargeted metabolomics study investigating metabolomic markers of e-cigarette exposure, including secondhand exposure, in a pregnant cohort. Despite this study's small size and exploratory nature, the results of this work suggest that flavoring components could be biomarkers for e-cigarette exposure, and that co-exposure to e-cigarettes and other drugs may be prevalent.

Around 40% of the US population and 1 in 6 individuals worldwide have obesity, with the incidence surging globally^1,2. Various dietary interventions, including carbohydrate, fat and, more recently, amino acid restriction, have been explored to combat this epidemic^3-6. Here we investigated the impact of removing individual amino acids on the weight profiles of mice. We show that conditional cysteine restriction resulted in the most substantial weight loss when compared to essential amino acid restriction, amounting to 30% within 1 week, which was readily reversed. We found that cysteine deficiency activated the integrated stress response and oxidative stress response, which amplify each other, leading to the induction of GDF15 and FGF21, partly explaining the phenotype^7-9. Notably, we observed lower levels of tissue coenzyme A (CoA), which has been considered to be extremely stable¹⁰, resulting in reduced mitochondrial functionality and metabolic rewiring. This results in energetically inefficient anaerobic glycolysis and defective tricarboxylic acid cycle, with sustained urinary excretion of pyruvate, orotate, citrate, α-ketoglutarate, nitrogen-rich compounds and amino acids. In summary, our investigation reveals that cysteine restriction, by depleting GSH and CoA, exerts a maximal impact on weight loss, metabolism and stress signalling compared with other amino acid restrictions. These findings suggest strategies for addressing a range of metabolic diseases and the growing obesity crisis.

A major challenge in the development of more effective therapeutic strategies for Alzheimer's disease (AD) is the identification of molecular mechanisms linked to specific pathophysiological features of the disease. Importantly AD has a two-fold higher incidence in women than men and a protracted prodromal phase characterized by amnestic mild-cognitive impairment (aMCI) suggesting that biological processes occurring early can initiate vulnerability to AD. Here, we used a sample of 125 subjects from two independent study cohorts to determine the levels in plasma (the most accessible specimen) of two essential mitochondrial markers acetyl-L-carnitine (LAC) and its derivative free-carnitine motivated by a mechanistic model in rodents in which targeting mitochondrial metabolism of LAC leads to the amelioration of cognitive function and boosts epigenetic mechanisms of gene expression. We report a sex-specific deficiency in free-carnitine levels in women with aMCI and early-AD compared to cognitively healthy controls; no change was observed in men. We also replicated the prior finding of decreased LAC levels in both women and men with AD, supporting the robustness of the study samples assayed in our new study. The magnitude of the sex-specific free-carnitine deficiency reflected the severity of cognitive dysfunction and held in two study cohorts. Furthermore, patients with the lower free-carnitine levels showed higher β-amyloid(Aβ) accumulation and t-Tau levels assayed in cerebrospinal fluid (CSF). Computational analyses showed that the mitochondrial markers assayed in plasma are at least as accurate as CSF measures to classify disease status. Together with the mechanistic platform in rodents, these translational findings lay the groundwork to create preventive individualized treatments targeting sex-specific changes in mitochondrial metabolism that may be subtle to early cognitive dysfunction of AD risk.