Teriflunomide Does Not Change Dynamics of Nadph Oxidase Activation and Neuronal Dysfunction During Neuroinflammation

NAD(P)H fluorescence lifetime imaging of live intestinal nematodes reveals metabolic crosstalk between parasite and host

Infections with intestinal nematodes have an equivocal impact: they represent a burden for human health and animal husbandry, but, at the same time, may ameliorate auto-immune diseases due to the immunomodulatory effect of the parasites. Thus, it is key to understand how intestinal nematodes arrive and persist in their luminal niche and interact with the host over long periods of time. One basic mechanism governing parasite and host cellular and tissue functions, metabolism, has largely been neglected in the study of intestinal nematode infections. Here we use NADH (nicotinamide adenine dinucleotide) and NADPH (nicotinamide adenine dinucleotide phosphate) fluorescence lifetime imaging of explanted murine duodenum infected with the natural nematode Heligmosomoides polygyrus and define the link between general metabolic activity and possible metabolic pathways in parasite and host tissue, during acute infection. In both healthy and infected host intestine, energy is effectively produced, mainly via metabolic pathways resembling oxidative phosphorylation/aerobic glycolysis features. In contrast, the nematodes shift their energy production from balanced fast anaerobic glycolysis-like and effective oxidative phosphorylation-like metabolic pathways, towards mainly anaerobic glycolysis-like pathways, back to oxidative phosphorylation/aerobic glycolysis-like pathways during their different life cycle phases in the submucosa versus the intestinal lumen. Additionally, we found an increased NADPH oxidase (NOX) enzymes-dependent oxidative burst in infected intestinal host tissue as compared to healthy tissue, which was mirrored by a similar defense reaction in the parasites. We expect that, the here presented application of NAD(P)H-FLIM in live tissues constitutes a unique tool to study possible shifts between metabolic pathways in host-parasite crosstalk, in various parasitic intestinal infections.

[The DRFZ-a pioneer in research on the interaction between immune and stromal cells during de- and regeneration of the musculoskeletal system]

Rheumatoid arthritis and osteoarthritis are two related chronic diseases of the musculoskeletal system which are particularly pronounced in the region of joints and bones. Their pathogeneses are associated with chronic inflammation, which can disrupt homeostasis in bones and articular cartilage. Degradation products deriving from articular cartilage can contribute to the exacerbation of inflammation in the joint region. Mechanical stimuli and blood vessels also play a central role in both the regulation of bone growth as well as in the regeneration of bone tissue. Not only chronic inflammatory processes but also hormonal changes after menopause or undesired effects of glucocorticoid therapy have an influence on the balance between bone resorption and deposition, by promoting the former and reducing the latter. This results in decreased bone quality and, in some cases, considerable loss of bone or osteoporosis. An in-depth understanding of these processes at the molecular, cellular, and tissue level, as well as of the changes present in chronic inflammatory diseases, has been the focus of research at the German Rheumatism Research Center (Deutsches Rheuma-Forschungszentrum, DRFZ) since its foundation. Based on an improved understanding of these mechanisms, the DRFZ aims to develop improved prevention and treatment strategies with effects even in early disease stages.

Altered substrate metabolism in neurodegenerative disease: new insights from metabolic imaging

Neurodegenerative diseases (NDs), such as Alzheimer's disease (AD), Parkinson's disease (PD) and multiple sclerosis (MS), are relatively common and devastating neurological disorders. For example, there are 6 million individuals living with AD in the United States, a number that is projected to grow to 14 million by the year 2030. Importantly, AD, PD and MS are all characterized by the lack of a true disease-modifying therapy that is able to reverse or halt disease progression. In addition, the existing standard of care for most NDs only addresses the symptoms of the disease. Therefore, alternative strategies that target mechanisms underlying the neuropathogenesis of disease are much needed. Recent studies have indicated that metabolic alterations in neurons and glia are commonly observed in AD, PD and MS and lead to changes in cell function that can either precede or protect against disease onset and progression. Specifically, single-cell RNAseq studies have shown that AD progression is tightly linked to the metabolic phenotype of microglia, the key immune effector cells of the brain. However, these analyses involve removing cells from their native environment and performing measurements in vitro, influencing metabolic status. Therefore, technical approaches that can accurately assess cell-specific metabolism in situ have the potential to be transformative to our understanding of the mechanisms driving AD. Here, we review our current understanding of metabolism in both neurons and glia during homeostasis and disease. We also evaluate recent advances in metabolic imaging, and discuss how emerging modalities, such as fluorescence lifetime imaging microscopy (FLIM) have the potential to determine how metabolic perturbations may drive the progression of NDs. Finally, we propose that the temporal, regional, and cell-specific characterization of brain metabolism afforded by FLIM will be a critical first step in the rational design of metabolism-focused interventions that delay or even prevent NDs.