Postprandial metabolomics analysis reveals disordered serotonin metabolism in post-bariatric hypoglycemia

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Abstract

BACKGROUND. Bariatric surgery is a potent therapeutic approach for obesity and type 2 diabetes but can be complicated by post-bariatric hypoglycemia (PBH). PBH typically occurs 1 to 3 hours after meals, in association with exaggerated postprandial levels of incretins and insulin. METHODS. To identify mediators of disordered metabolism in PBH, we analyzed plasma metabolome in fasting state and 30 and 120 minutes after mixed meal in 3 groups: PBH (n = 13), asymptomatic post-RYGB (n = 10), and non-surgical controls (n = 8). RESULTS. In the fasting state, multiple tricarboxylic acid cycle intermediates and the ketone beta-hydroxybutyrate were increased by 30% to 80% in PBH vs. asymptomatic. Conversely, multiple amino acids (BCAA, tryptophan) and polyunsaturated lipids were reduced by 20% to 50% in PBH versus asymptomatic. Tryptophan-related metabolites, including kynurenate, xanthurenate, and serotonin, were reduced by 2- to 10-fold in PBH in fasting state. Postprandially, plasma serotonin was uniquely increased by 1.9-fold in PBH versus asymptomatic post-RYGB. In mice, serotonin administration lowered glucose and increased plasma insulin and GLP-1. Moreover, serotonin-induced hypoglycemia in mice was blocked by the nonspecific serotonin receptor antagonist cyproheptadine and the specific serotonin receptor 2 antagonist ketanserin. CONCLUSION. Together these data suggest that increased postprandial serotonin may contribute to the pathophysiology of PBH and provide a potential therapeutic target. FUNDING. NIH grant R01 DK121995, NIH grant P30 DK036836 (Diabetes Research Center grant, Joslin Diabetes Center), and Fundação de Amparo à Pesquisa do Estado de São Paulo-FAPESP grant 2018/22111-2.

Authors

Rafael Ferraz-Bannitz, Berkcan Ozturk, Cameron J. Cummings, Vissarion Efthymiou, Pilar Casanova Querol, Lindsay Poulos, Hanna J. Wang, Valerie Navarrete, Hamayle Saeed, Christopher M. Mulla, Hui Pan, Jonathan M. Dreyfuss, Donald C. Simonson, Darleen A. Sandoval, Mary-Elizabeth Patti

Uterine cyclin A2 deficient mice as a model of female early pregnancy loss

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Abstract

Proper action of the female sex steroids, 17β-estradiol (E2) and progesterone (P4) on endometrium is essential for fertility. Beyond its role in regulating the cell cycle, cyclin A2 (CCNA2) also mediates E2 and P4 signaling in vitro, but a potential role in modulating steroid action for proper endometrial tissue development and function is unknown. To fill this gap in our knowledge, we examined human endometrial tissue from fertile and infertile women for CCNA2 expression and correlated this with pregnancy outcome. Functional assessment of CCNA2 was validated in vivo using a conditional Ccna2 uterine deficient mouse model while in vitro function was assessed using human cell culture models. We found that CCNA2 expression was significantly reduced in endometrial tissue, specifically the stromal cells, from women undergoing in vitro fertilization who failed to achieve pregnancy. Conditional deletion of Ccna2 from mouse uterine tissue resulted in an inability to achieve pregnancy which appears to be due to alterations in the process of decidualization, which was confirmed using in vitro models. From these studies, we conclude that CCNA2 expression during the proliferative/regenerative stage of the menstrual cycle acts as a safeguard allowing for proper steroid responsiveness, decidualization and pregnancy. When CCNA2 expression levels are insufficient there is impaired endometrial responsiveness, aberrant decidualization and loss of pregnancy.

Authors

Fatimah Aljubran, Katelyn Schumacher, Amanda Graham, Sumedha Gunewardena, Courtney Marsh, Michael Lydic, Kristin Holoch, Warren B. Nothnick

A six-year study in a real-world population reveals an increased incidence of dyslipidemia during COVID-19

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Abstract

BACKGROUND. Recent studies conducted in COVID-19 survivors suggest that SARS-CoV-2 infection is associated with an increased risk of dyslipidemia. However, it remains unclear whether this augmented risk is confirmed in the general population and how this phenomenon is impacting the overall burden of cardiometabolic diseases. METHODS. To address these aspects, we conducted a 6-year longitudinal study to examine the broader effects of COVID-19 on dyslipidemia incidence within a real-world population (228,266 subjects) residing in Naples, Southern Italy. The pre-COVID-19 and the COVID-19 groups were balanced for demographic and clinical factors using propensity score matching. RESULTS. Our analysis spans over a period of three years during the pandemic (2020–2022), comparing dyslipidemia incidence with pre-pandemic data (2017–2019), with a follow-up time of at least 1,095 days corresponding to 21,349,215 person-years. During the COVID-19 period we detected an increased risk of developing any dyslipidemia when compared with the pre-COVID-19 triennium (OR = 1.29, 95% CI 1.19–1.39). Importantly, these estimates were adjusted for comorbidities by a multivariate analysis. CONCLUSIONS. Taken together, our data reveal a notable rise in dyslipidemia incidence amid the COVID-19 pandemic, suggesting to establish specialized clinical monitoring protocols for COVID-19 survivors to mitigate the risk of dyslipidemia development.

Authors

Valentina Trimarco, Raffaele Izzo, Stanislovas S. Jankauskas, Mario Fordellone, Giuseppe Signoriello, Maria Virginia Manzi, Maria Lembo, Paola Gallo, Giovanni Esposito, Roberto Piccinocchi, Francesco Rozza, Carmine Morisco, Pasquale Mone, Gaetano Piccinocchi, Fahimeh Varzideh, Bruno Trimarco, Gaetano Santulli

Epigenetic regulation of cell state by H2AFY governs immunogenicity in high-risk neuroblastoma

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Abstract

Childhood neuroblastoma with MYCN-amplification is classified as high-risk and often relapses after intensive treatments. Immune checkpoint blockade therapy against the PD-1/L1 axis shows limited efficacy in neuroblastoma patients and the cancer intrinsic immune regulatory network is poorly understood. Here, we leverage genome-wide CRISPR/Cas9 screens and identify H2AFY as a resistance gene to the clinically approved PD-1 blocking antibody, nivolumab. Analysis of single-cell RNA sequencing datasets reveals that H2AFY mRNA is enriched in adrenergic cancer cells and is associated with worse patient survival. Genetic deletion of H2afy in MYCN-driven neuroblastoma cells reverts in vivo resistance to PD-1 blockade by eliciting activation of the adaptive and innate immunity. Mapping of the epigenetic and translational landscape demonstrates that H2afy deletion promotes cell transition to a mesenchymal-like state. With a multi-omics approach, we uncover H2AFY-associated genes that are functionally relevant and prognostic in patients. Altogether, our study elucidates the role of H2AFY as an epigenetic gatekeeper for cell states and immunogenicity in high-risk neuroblastoma.

Authors

Divya Nagarajan, Rebeca T. Parracho, David Corujo, Minglu Xie, Ginte Kutkaite, Thale K. Olsen, Marta Rúbies Bedós, Maede Salehi, Ninib Baryawno, Michael P. Menden, Xingqi Chen, Marcus Buschbeck, Yumeng Mao

Metabolic rewiring during bone development underlies tRNA m⁷G-associated primordial dwarfism

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Abstract

Translation of mRNA to protein is tightly regulated by tRNAs, which are subject to various chemical modifications that maintain the structure, stability and function. Deficiency of tRNA N7-methylguanosine (m7G) modification in patients causes a type of primordial dwarfism, but the underlying mechanism remains unknown. Here we report the loss of m7G rewires cellular metabolism, leading to the pathogenesis of primordial dwarfism. Conditional deletion of the catalytic enzyme Mettl1 or missense mutation of the scaffold protein Wdr4 severely impaired endochondral bone formation and bone mass accrual. Mechanistically, Mettl1 knockout decreased abundance of m7G-modified tRNAs and inhibited translation of mRNAs relating to cytoskeleton and Rho GTPase signaling. Meanwhile, Mettl1 knockout enhanced cellular energy metabolism despite of incompetent proliferation and osteogenic commitment. Further exploration revealed that impaired Rho GTPase signaling upregulated branched-chain amino acid transaminase 1 (BCAT1) level that rewired cell metabolism and restricted intracellular α-ketoglutarate (αKG). Supplementation of αKG ameliorated the skeletal defect of Mettl1-deficient mice. In addition to the selective translation of metabolism-related mRNAs, we further revealed that Mettl1 knockout globally regulated translation via integrated stress response (ISR) and mammalian target of rapamycin complex 1 (mTORC1) signaling. Restoring translation either by targeting ISR or mTORC1 aggravated bone defects of Mettl1-deficient mice. Overall, our study unveils a critical role of m7G tRNA modification in bone development by regulating cellular metabolism, and indicates that suspension of translation initiation as quality control mechanism in response to tRNA dysregulation.

Authors

Qiwen Li, Shuang Jiang, Kexin Lei, Hui Han, Yaqian Chen, Weimin Lin, Qiuchan Xiong, Xingying Qi, Xinyan Gan, Rui Sheng, Yuan Wang, Yarong Zhang, Jieyi Ma, Tao Li, Shuibin Lin, Chenchen Zhou, Demeng Chen, Quan Yuan

Longitudinal analysis of viral dynamics in HIV⁺ to HIV⁺ HOPE Act kidney-transplant recipients

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Abstract

BACKGROUND. The HIV Organ Policy Equity (HOPE) Act allows individuals living with HIV to accept organs from donors with HIV. This practice widens the pool of available organs, but also presents important virological questions, including the potential for HIV superinfection of the recipient, viral persistence in the kidney, and loss of virological control. METHODS. We addressed these questions by performing in-depth longitudinal viral sequence analyses on urine, blood, and urine-derived renal epithelial cells from twelve recipients of HIV+ kidney allografts. RESULTS. We amplified donor-derived HIV-1 env sequences in 5 out of 12 recipients post-transplant. These donor-derived env sequences were amplified from recipient urine, urine-derived renal epithelial cells, and plasma between 12 and 96-hours post-transplant and remained detectable up to 16-days post-transplant. Env sequences were also detected in kidney biopsies taken from the allografts before implantation in 6 out of the 12 transplant cases, indicating the presence of donor virus within the organ. One recipient had a viremic episode 3.5 years after transplantation as a result of ART interruption. Only recipient strain viral sequences were detected in blood, suggesting that the donor virus, if still present, was not reactivated during the temporary ART withdrawal. CONCLUSIONS. This study demonstrates that the HIV env sequences in a donor kidney can be amplified from biopsies taken from the allograft before implantation and can be detected transiently in blood and urine samples collected from the organ recipients post-transplantation.

Authors

Tatianna Travieso, Hannah Stadtler, Naseem Alavian, Feng Gao, Mary Klotman, Cameron R. Wolfe, Maria Blasi

Il-13 induces loss of CFTR in ionocytes and reduces airway epithelial fluid absorption

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Abstract

The airway surface liquid (ASL) plays a crucial role in lung defense mechanisms, and its composition and volume are regulated by the airway epithelium. The cystic fibrosis transmembrane conductance regulator (CFTR) is abundantly expressed in a rare airway epithelial cell type called an ionocyte. Recently, we demonstrated that ionocytes can increase liquid absorption through apical CFTR and basolateral barttin/chloride channels, while airway secretory cells mediate liquid secretion through apical CFTR channels and basolateral NKCC1 transporters. Th2-driven (IL-4/IL-13) airway diseases, such as asthma, cause goblet cell metaplasia, accompanied by increased mucus production and airway secretions. In this study, we investigate the effect of IL-13 on chloride and liquid transport performed by ionocytes. IL-13 treatment of human airway epithelia was associated with reduced epithelial liquid absorption rates and increased ASL volume. Additionally, IL-13 treatment reduced the abundance of CFTR-positive ionocytes and increased the abundance of CFTR-positive secretory cells. Increasing ionocyte abundance attenuated liquid secretion caused by IL-13. Finally, CFTR-positive ionocytes were less common in asthma and COPD and associated with airflow obstruction. Our findings suggest that loss of CFTR in ionocytes contributes to the liquid secretion observed in IL-13-mediated airway diseases.

Authors

Guillermo S. Romano Ibarra, Lei Lei, Wenjie Yu, Andrew L. Thurman, Nicholas D. Gansemer, David K. Meyerholz, Alejandro A. Pezzulo, Paul B. McCray, Ian M. Thornell, David A. Stoltz

Antibiotic use during influenza infection augments lung eosinophils that impair immunity against secondary bacterial pneumonia

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Abstract

A leading cause of mortality after influenza infection is the development of a secondary bacterial pneumonia. In the absence of a bacterial superinfection, prescribing antibacterial therapies is not indicated but has become a common clinical practice for those presenting with a respiratory viral illness. In a murine model, we found that antibiotic use during influenza infection impaired the lung innate immunologic defenses toward a secondary challenge with methicillin-resistant Staphylococcus aureus (MRSA). Antibiotics augment lung eosinophils, which have inhibitory effects on macrophage function through the release of major basic protein. Moreover, we demonstrated antibiotic treatment during influenza infection causes a fungal dysbiosis that drive lung eosinophilia and impair MRSA clearance. Finally, we evaluated three cohorts of hospitalized patients and found eosinophils positively correlated with antibiotic use, systemic inflammation, and worsened outcomes. Altogether, our work demonstrates a detrimental effect of antibiotic treatment during influenza infection that has harmful immunologic consequences via recruitment of eosinophils to the lungs thereby increasing the risk of developing a secondary bacterial infection.

Authors

Marilia Sanches Santos Rizzo Zuttion, Tanyalak Parimon, Stephanie A. Bora, Changfu Yao, Katherine Lagree, Catherine A. Gao, Richard G. Wunderink, Georgios D. Kitsios, Alison Morris, Yingze Zhang, Bryan J. McVerry, Matthew E. Modes, Alberto M. Marchevsky, Barry R. Stripp, Christopher M. Soto, Ying Wang, Kimberly Merene, Silvia Cho, Blandine L. Victor, Ivan Vujkovic-Cvijin, Suman Gupta, Suzanne Cassel, Fayyaz S. Sutterwala, Suzanne Devkota, David M. Underhill, Peter Chen

Elexacaftor/tezacaftor/ivacaftor’s effects on cystic fibrosis infections are maintained but not increased after 3.5-years of treatment

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Abstract

Authors

Sarah J. Morgan, Ellis Coulter, Hannah L. Betts, George M. Solomon, John P. Clancy, Steven M. Rowe, David P. Nichols, Pradeep K. Singh

Parkin activates innate immunity and promotes anti-tumor immune responses

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The activation of innate immunity and associated interferon (IFN) signaling have been implicated in cancer, but the regulators are elusive and a link to tumor suppression undetermined. Here, we found that Parkin, an E3 ubiquitin ligase altered in Parkinson’s Disease was epigenetically silenced in cancer and its re-expression by clinically approved demethylating therapy stimulated transcription of a potent IFN response in tumor cells. This pathway required Parkin E3 ubiquitin ligase activity, involved the subcellular trafficking and release of the alarmin High Mobility Group Box 1 (HMGB1) and was associated with inhibition of NFκB gene expression. In turn, Parkin-expressing cells released an IFN secretome that upregulated effector and cytotoxic CD8 T cell markers, lowered the expression of immune inhibitory receptors, TIM3 and LAG3, and stimulated high content of the self-renewal/stem cell factor, TCF1. Parkin-induced CD8 T cells selectively accumulated in the microenvironment and inhibited transgenic and syngeneic tumor growth, in vivo. Therefore, Parkin is an epigenetically regulated activator of innate immunity and dual mode tumor suppressor, inhibiting intrinsic tumor traits of metabolism and cell invasion, while simultaneously reinvigorating CD8 T cell functions in the microenvironment.

Authors

Michela Perego, Minjeong Yeon, Ekta Agarwal, Andrew T. Milcarek, Irene Bertolini, Chiara Camisaschi, Jagadish C. Ghosh, Hsin-Yao Tang, Nathalie Grandvaux, Marcus Ruscetti, Andrew V. Kossenkov, Sarah Preston-Alp, Italo Tempera, Noam Auslander, Dario C. Altieri