Biology subjects

Divanovic, S.

Publications and source records attributed to Divanovic, S..

6 recordsLinked to original sources

bioRxiv2026

IL1 blockade attenuates E. coli induced intrauterine inflammation and preterm labor in Rhesus macaques

Intrauterine infection and inflammation are major causes of preterm labor, yet antibiotics alone often fail to prevent preterm birth despite achieving microbial clearance. Interleukin1 (IL1) is a key mediator of intra-amniotic inflammation and functional progesterone withdrawal, processes linked to labor initiation. We tested whether IL1 blockade with the clinically approved IL1 receptor antagonist, anakinra, could reduce inflammation and preterm labor in a Rhesus macaque model of intra-amniotic Escherichia coli infection followed by delayed antibiotic treatment. Here we show that anakinra reduced the incidence of preterm labor by 40% (p=0.07), attenuated inflammation in the fetal membranes and cervix, and preserved progesterone receptor-B abundance in the fetal membranes. These effects were most pronounced in animals protected from preterm labor. Our findings in a relevant model support the translational potential of combining IL1 blockade with antibiotics for infection-associated preterm labor. One sentence summaryRecombinant human IL1 receptor antagonist (anakinra) decreased E. coli infection induced preterm labor and partially decreased intrauterine inflammation in a non-human primate model of inflammation mediated preterm labor.

immunology↗

bioRxiv2024

Patient-derived colon epithelial organoids reveal lipid-related metabolic dysfunction in pediatric ulcerative colitis

Background & AimsUlcerative colitis (UC) is associated with epithelial metabolic derangements which exacerbate gut inflammation. Patient-derived organoids recapitulate complexities of the parent tissue in health and disease; however, whether colon organoids (colonoids) model metabolic impairments in the pediatric UC epithelium is unclear. This study determined the functional metabolic differences in the colon epithelia using epithelial colonoids from pediatric patients. MethodsWe developed biopsy-derived colonoids from pediatric patients with endoscopically active UC, inactive UC, and those without endoscopic or histologic evidence of colon inflammation (non-IBD controls). We extensively interrogated metabolic dysregulation through extracellular flux analyses and tested potential therapies that recapitulate or ameliorate such metabolic dysfunction. ResultsEpithelial colonoids from active UC patients exhibit elevated oxygen consumption and proton leak supported by enhanced glycolytic capacity and dysregulated lipid metabolism. The hypermetabolic features in active UC colonoids were associated with increased cellular stress and chemokine secretion, specifically during differentiation. Transcriptomic and pathway analyses indicated a role for PPAR- in lipid-induced hypermetabolism in active UC colonoids, which was validated by PPAR- activation in non-IBD colonoids. Accordingly, limiting neutral lipid accumulation in active UC colonoids through pharmacological inhibition of PPAR- induced a metabolic shift towards glucose consumption, suppressed hypermetabolism and chemokine secretion, and improved cellular stress markers. Control and inactive UC colonoids had similar metabolic and transcriptomic profiles. ConclusionsOur pediatric colonoids revealed significant lipid-related metabolic dysregulation in the pediatric UC epithelium that may be alleviated by PPAR- inhibition. This study supports the advancement of colonoids as a preclinical human model for testing epithelial-directed therapies against such metabolic dysfunction. What You Need to KnowO_ST_ABSBackground and ContextC_ST_ABSColon mucosa healing in pediatric UC requires reinstating normal epithelial function but a lack of human preclinical models of the diseased epithelium hinders the development of epithelial-directed interventions. New FindingsUsing colon biopsy-derived epithelial organoids, samples from pediatric patients with active UC show hyperactive metabolic function largely driven by enhanced lipid metabolism. Pharmacologic inhibition of lipid metabolism alleviates metabolic dysfunction, cellular stress, and chemokine production. LimitationsThough our epithelial colon organoids from active UC patients show targetable metabolic and molecular features from non-IBD controls, they were cultured under sterile conditions, which may not fully capture any potential real-time contributions of the complex inflammatory milieu typically present in the disease. Clinical Research RelevanceCurrent therapies for pediatric UC mainly target the immune system despite the need for epithelial healing to sustain remission. We identified a pharmacologic target that regulates epithelial metabolism and can be developed for epithelial-directed therapy in UC. Basic Research RelevancePediatric UC patient tissue adult stem cell-derived colon epithelial organoids retain disease-associated metabolic pathology and can serve as preclinical human models of disease. Excess reliance on lipids as an energy source leads to oxidative and inflammatory dysfunction in pediatric UC colon organoids. Preprint: This manuscript is currently on bioRxiv. doi: https://doi.org/10.1101/2024.08.22.609271 Lay Summary: Using patient tissue-derived colon epithelial organoids, the investigators identified epithelial metabolic dysfunction and inflammation in pediatric ulcerative colitis that can be alleviated by PPAR-a inhibition.

physiology↗

bioRxiv2023

GalNAc-siRNA Mediated Knockdown of Ketohexokinase Versus Systemic, Small Molecule Inhibition of its Kinase Activity Exert Divergent Effects on Hepatic Metabolism in Mice on a HFD

Consumption of diets high in sugar and fat are well-established risk factors for the development of obesity and its metabolic complications, including non-alcoholic fatty liver disease. Metabolic dysfunction associated with sugar intake is dependent on fructose metabolism via ketohexokinase (KHK). Here, we compared the effects of systemic, small molecule inhibition of KHK enzymatic activity to hepatocyte-specific, GalNAc-siRNA mediated knockdown of KHK in mice on a HFD. Both modalities led to an improvement in liver steatosis, however, via substantially different mechanisms. KHK knockdown profoundly decreased lipogenesis, while the inhibitor increased the fatty acid oxidation pathway. Moreover, hepatocyte-specific KHK knockdown completely prevented hepatic fructose metabolism and improved glucose tolerance. Conversely, KHK inhibitor only partially reduced fructose metabolism, but it also decreased downstream triokinase. This led to the accumulation of fructose-1 phosphate, resulting in glycogen accumulation, hepatomegaly, and impaired glucose tolerance. In summary, KHK profoundly impacts hepatic metabolism, likely via both kinase-dependent and independent mechanisms. HIGHLIGHTSO_LIKHK knockdown or inhibition of its kinase activity differently target hepatic metabolism. C_LIO_LIKHK inhibitor increases F1P and glycogen accumulation as it also lowers triokinase. C_LIO_LIKHK knockdown completely prevents hepatic fructose metabolism and lipogenesis. C_LIO_LIE of wild type, but not mutant, kinase dead KHK-C increases glycogen accumulation. C_LI

molecular biology↗

bioRxiv2023

Fructose Induced KHK-C Increases ER Stress and Modulates Hepatic Transcriptome to Drive Liver Disease in Diet-Induced and Genetic Models of NAFLD.

Non-alcoholic fatty liver disease (NAFLD) is a liver manifestation of metabolic syndrome, and is estimated to affect one billion individuals worldwide. An increased intake of a high-fat diet (HFD) and sugar-sweetened beverages are risk-factors for NAFLD development, but how their combined intake promotes progression to a more severe form of liver injury is unknown. Here we show that fructose metabolism via ketohexokinase (KHK) C isoform increases endoplasmic reticulum (ER) stress in a dose dependent fashion, so when fructose is coupled with a HFD intake it leads to unresolved ER stress. Conversely, a liver-specific knockdown of KHK in C57BL/6J male mice consuming fructose on a HFD is adequate to improve the NAFLD activity score and exert a profound effect on the hepatic transcriptome. Overexpression of KHK-C in cultured hepatocytes is sufficient to induce ER stress in fructose free media. Upregulation of KHK-C is also observed in genetically obesity ob/ob, db/db and lipodystrophic FIRKO male mice, whereas KHK knockdown in these mice improves metabolic function. Additionally, in over 100 inbred strains of male or female mice hepatic KHK expression correlates positively with adiposity, insulin resistance, and liver triglycerides. Similarly, in 241 human subjects and their controls, hepatic Khk expression is upregulated in early, but not late stages of NAFLD. In summary, we describe a novel role of KHK-C in triggering ER stress, which offers a mechanistic understanding of how the combined intake of fructose and a HFD propagates the development of metabolic complications.

molecular biology↗

bioRxiv2021

In Vivo Generation of Bone Marrow from Embryonic Stem Cells in Interspecies Chimeras

Generation of bone marrow (BM) from embryonic stem cells (ESCs) or induced pluripotent stem cells (iPSCs) promises to accelerate the development of future cell therapies for life-threatening disorders. However, such approach is limited by technical challenges to produce a mixture of functional BM progenitor cells able to replace all hematopoietic cell lineages. Herein, we used blastocyst complementation to simultaneously produce all BM hematopoietic cell lineages from mouse ESCs in a rat. Based on FACS analysis and single-cell RNA sequencing, mouse ESCs differentiated into hematopoietic progenitor cells and multiple hematopoietic cell types that were indistinguishable from normal mouse BM cells based on gene expression signatures and cell surface markers. Transplantation of ESC-derived BM cells from mouse-rat chimeras rescued lethally-irradiated syngeneic mice and resulted in long-term contribution of donor cells to hematopoietic cell lineages. Altogether, a fully functional bone marrow was generated from mouse ESCs using rat embryos as "bioreactors". KEY POINTS- We used blastocyst complementation to simultaneously produce all bone marrow hematopoietic cell lineages from mouse ESCs in a rat. - ESC-derived cells from mouse-rat chimeras were fully functional and exhibited normal gene expression signatures and cell surface markers.

developmental biology↗

bioRxiv2021

The intensity of the immune response to LPS and E. coli regulates the induction of preterm labor in Rhesus Macaques

Intrauterine infection/inflammation (IUI) is a major contributor to preterm labor (PTL). However, IUI does not invariably cause PTL. We hypothesized that quantitative and qualitative differences in immune response exist in subjects with or without PTL. To define the triggers for PTL, we developed Rhesus macaque models of IUI driven by lipopolysaccharyde (LPS) or live E. coli. PTL did not occur in LPS challenged Rhesus macaque while E. coli infected animals frequently delivered preterm. Although LPS and live E. coli both caused immune cell infiltration, E. coli infected animals showed higher levels of inflammatory mediators, particularly IL6 and prostaglandins, in the chorioamnion decidua and amniotic fluid. Neutrophil infiltration in the chorion was a common feature to both LPS and E. coli. However, neutrophilic infiltration and IL6 and PTGS2 expression in the amnion was specifically induced by live E. coli. RNASeq analysis of fetal membranes revealed that specific pathways involved in augmentation of inflammation including type I interferon response, chemotaxis, sumoylation and iron homeostasis were upregulated in the E. coli group compared to the LPS group. Our data suggest that intensity of the host immune response to IUI may determine susceptibility to PTL.

immunology↗