Oral cavity squamous cell carcinoma (OCC) and oropharyngeal squamous cell carcinoma (OPC) are among the most common cancers worldwide and are associated with high mortality and morbidity. The purpose of this study is to identify potential biomarkers to distinguish OCC/OPC from normal controls and to distinguish OCC patients with and without nodal metastasis. We tested saliva samples from 101 OCC, 58 OPC, and 35 normal controls using four analytical platforms (NMR, targeted aqueous by LC-MS/MS, global aqueous and global lipidomics by LC-Q-TOF). Samples from OCC and normal controls were divided into discovery and validation sets. Using linear regression adjusting for age, sex, race and experimental batches, we found the levels of two metabolites (glycine and proline) to be significantly different between OCC and controls (FDR < 0.1 for both discovery and validation sets) but did not find any appreciable differences in metabolite levels between OPC and controls or between OCC with and without nodal metastasis. Four metabolites, including glycine, proline, citrulline, and ornithine were associated with early stage OCC in both discovery and validation sets. Further study is warranted to confirm these results in the development of salivary metabolites as diagnostic markers.
The gut microbiota contributes to metabolic disease, and diet shapes the gut microbiota, emphasizing the need to better understand how diet impacts metabolic disease via gut microbiota alterations. Fiber intake is linked with improvements in metabolic homeostasis in rodents and humans, which is associated with changes in the gut microbiota. However, dietary fiber is extremely heterogenous, and it is imperative to comprehensively analyze the impact of various plant-based fibers on metabolic homeostasis in an identical setting and compare the impact of alterations in the gut microbiota and bacterially derived metabolites from different fiber sources. The objective of this study is to analyze the impact of different plant-based fibers (pectin, beta-glucan, wheat dextrin, resistant starch, and cellulose as a control) on metabolic homeostasis through alterations in the gut microbiota and its metabolites in high-fat diet (HFD)-fed mice. HFD-fed mice were supplemented with 5 different fiber types (pectin, beta-glucan, wheat dextrin, resistant starch, or cellulose as a control) at 10% (w/w) for 18 weeks (n=12/group), measuring body weight, adiposity, indirect calorimetry, glucose tolerance, and the gut microbiota and metabolites. Only beta-glucan supplementation during HFD-feeding decreased adiposity and body weight gain and improved glucose tolerance compared to HFD-cellulose, while all other fibers had no effect. This was associated with increased energy expenditure and locomotor activity in mice compared to HFD-cellulose. All fibers supplemented into a HFD uniquely shifted the intestinal microbiota and cecal short-chain fatty acids, however only beta-glucan supplementation increased cecal butyrate levels. Lastly, all fibers altered the small intestinal microbiota and portal bile acid composition. These findings demonstrate that beta-glucan consumption is a promising dietary strategy for metabolic disease, possibly via increased energy expenditure through alterations in the gut microbiota and bacterial metabolites in mice.
Heart failure occurs at nearly twice the rate in diabetic patients as compared to normal patients. NAD levels are reduced in both human and murine models of heart disease, including those with diabetes. Strategies to raise NAD in these models have primarily focused on increasing NAD synthesis. Alternatively, inhibition of NAD consumption provides another viable path to increasing NAD levels in diabetic hearts. Sterile Alpha and Tir Motif Containing 1 (SARM1) is an NAD hydrolase that mediates axonal degeneration through NAD degradation and promotion of mitochondrial dysfunction. However, the role SARM1 plays in heart disease has not been investigated. We subjected male wild type (WT) and global SARM1 knockout mice (KO) to chronic diabetic stress induced by streptozotocin injections. We showed that 16-week diabetic stress promoted progressive decline in systolic and diastolic function as measured by longitudinal echocardiography. SARM1 deletion (diabetic KO) improved both systolic and diastolic function of diabetic mice, despite similar glucose, and plasma aqueous and lipid metabolite levels as the diabetic wild-type mice. Diabetic KO hearts showed elevated NAD levels, suggesting that SARM1 may be activated to promote NAD decline in diabetic hearts. Transcriptomic analysis identified 1948 differentially expressed genes in diabetic WT hearts, compared to non-diabetic WT hearts. Gene Module Network Analysis identified upregulation of fatty acid metabolic processes and suppression of genes involved in mitochondrial processes in diabetic hearts. SARM1 deficiency reversed the upregulated fatty acid metabolic genes, improved mitochondrial respiration, and elevated NAD levels in diabetic hearts. Transmission electron microscopy of the hearts indicated the diabetic WT had substantial accumulation of lipid droplets. SARM1 deficiency abrogated these lipid abnormalities. In conjunction, we performed Oil Red O staining and found that levels of lipid accumulation were reduced in the diabetic KO hearts. Finally, we measured levels of O-linked N-acetylglucosamine (O-glycNAc) and found that these were elevated in diabetic hearts and reduced by SARM1 deficiency. Altogether, we found that SARM1 may play a role in the lipotoxicity and glucotoxicity seen in diabetic hearts by inducing mitochondrial dysfunction and modifying metabolic transcriptional networks. Future analysis will shed light on how SARM1 contributes to lipotoxicity and glucotoxicity as a new pathogenic mechanism of diabetic cardiomyopathy.
Abstract Voluntary caloric restriction (e.g., eating disorders) often results in alterations in the gut microbiota composition and function. However, these findings may not translate to food insecurity, where an individual experiences inconsistent access to healthy food options. In this study we compared the fecal microbiome and metabolome of racially and ethnically diverse first year college students ( n = 60) experiencing different levels of food access. Students were dichotomized into food secure (FS) and food insecure (FI) groups using a validated, 2-question screener assessing food security status over the previous 30 days. Fecal samples were collected up to 5 days post survey-completion. Gut microbiome and metabolome were established using 16S rRNA amplicon sequencing, targeted liquid chromatography-tandem mass spectrometry, and gas chromatography-mass spectrometry. FI students experienced significantly greater microbial diversity with increased abundance of Enterobacteriaceae and Eisenbergiella, while FS students had greater abundance of Megasphaera and Holdemanella . Metabolites related to energy transfer and gut–brain-axis communication (picolinic acid, phosphocreatine, 2-pyrrolidinone) were elevated in FI students ( q < 0.05). These findings suggest that food insecurity is associated with differential gut microbial and metabolite composition for which the future implications are unknown. Further work is needed to elucidate the longitudinal metabolic effects of food insecurity and how gut microbes influence metabolic outcomes.
Diabetes is a major risk factor of heart failure. Diabetes and heart failure have been linked to altered NAD metabolism, whose roles in the progression of diabetic cardiomyopathy (DC) are far from established. We induced diabetes in wild type C57BL6N mice (WT) by streptozotocin (STZ) injections. WT mice with chronic diabetic stress (fasting glucose ~600 mg/dl) for 16 weeks had gradual declines in systolic and diastolic function and lowered NAD/NADH ratio, while acute STZ treatment (1‐day) did not affect cardiac function and NAD pool. To determine whether NAD redox imbalance promotes DC, we employed cardiac‐specific Ndufs4‐KO mice (cKO), which exhibit lowered cardiac NAD/NADH ratio without overt dysfunction. While insulin depletion and hyperglycemia were similar in diabetic control and cKO mice stressed by the same diabetogenic protocol, systolic and diastolic dysfunctions were accelerated in diabetic cKO mice. We next determined how NAD metabolism is altered to accelerate DC. In addition to the NAD redox balance, NAD metabolism also involves metabolites and enzymes in the NAD consumption and synthesis pathways, coordinating the homeostasis of NAD. Targeted analyses of transcripts and metabolites involved in these pathways were performed using qPCR and quantitative LC‐MS/MS analyses. Of 22 genes measured, we identified that Nmrk mRNA levels were up‐regulated in diabetic cKO hearts, compared to diabetic control hearts. Of thirteen cardiac NAD metabolite levels surveyed, product metabolites of NMRK enzymatic reaction (i.e. NMN or NAMN) showed decreases in levels in diabetic cKO hearts. The transcript and metabolite data suggest a role of NMRK in DC. Histologically, cardiac fibrosis levels of diabetic control and cKO hearts were slightly elevated compared to non‐diabetic controls, but they were not different. The results suggest that the accelerated decline of cardiac function in diabetic cKO hearts is not be due to altered extracellular matrix environment. We next analyzed acetylation‐dependent pathways to account for the accelerated decline of function in diabetic cKO hearts. NAD redox imbalance in diabetic cKO hearts promoted protein acetylation, including SOD2 acetylation (SOD2‐K68Ac). SOD2 acetylation inhibits its antioxidant function and we observed elevated protein oxidation levels in diabetic cKO hearts. To gain further insights how NAD redox imbalance may regulate cardiomyocyte function, phosphorylation levels of myosin binding protein C (MyBPC) and troponin I (TnI) were examined. In diabetic cKO hearts, TnI phosphorylation was elevated while MyBPC phosphorylation remained unchanged, suggesting a regulation of cardiomyocyte contraction/relaxation by NAD‐dependent mechanisms. To normalize NAD redox imbalance, we elevated NAD levels in diabetic cKO mice with cardiac‐specific NAMPT overexpression. Cardiac NAMPT expression slowed the accelerated decline of systolic and diastolic functions in diabetic cKO hearts. Our results support that altered NAD metabolism is a critical determinant for the progression of DC and warrants further investigations. Support or Funding Information 1. Scientist Development Grant, AHA 2. Seed Funding, Presbyterian Health Foundation of Oklahoma City 1.
Abstract Smoke from wildland fires has been shown to produce neuroinflammation in preclinical models, characterized by neural infiltrations of neutrophils and monocytes, as well as altered neurovascular endothelial phenotypes. To address the longevity of such outcomes, the present study examined the temporal dynamics of neuroinflammation and metabolomics after inhalation exposures from biomass-derived smoke. 2-month-old female C57BL/6 J mice were exposed to wood smoke every other day for 2 weeks at an average exposure concentration of 0.5 mg/m 3 . Subsequent serial euthanasia occurred at 1-, 3-, 7-, 14-, and 28-day post-exposure. Flow cytometry of right hemispheres revealed two endothelial populations of CD31 Hi and CD31 Med expressors, with wood smoke inhalation causing an increased proportion of CD31 Hi . These populations of CD31 Hi and CD31 Med were associated with an anti-inflammatory and pro-inflammatory response, respectively, and their inflammatory profiles were largely resolved by the 28-day mark. However, activated microglial populations (CD11b + /CD45 low ) remained higher in wood smoke-exposed mice than controls at day 28. Infiltrating neutrophil populations decreased to levels below controls by day 28. However, the MHC-II expression of the peripheral immune infiltrate remained high, and the population of neutrophils retained an increased expression of CD45, Ly6C, and MHC-II. Utilizing an unbiased approach examining the metabolomic alterations, we observed notable hippocampal perturbations in neurotransmitter and signaling molecules, such as glutamate, quinolinic acid, and 5-α-dihydroprogesterone. Utilizing a targeted panel designed to explore the aging-associated NAD + metabolic pathway, wood smoke exposure drove fluctuations and compensations across the 28-day time course, ending with decreased hippocampal NAD + abundance on day 28. Summarily, these results indicate a highly dynamic neuroinflammatory environment, with potential resolution extending past 28 days, the implications of which may include long-term behavioral changes, systemic and neurological sequalae directly associated with wildfire smoke exposure.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)