Caspase-2 has been shown to be involved in metabolic homeostasis. Here, we show that caspase-2 deficiency alters basal energy metabolism by shifting the balance in fuel choice from fatty acid to carbohydrate usage. At 4 weeks of age, whole-body carbohydrate utilisation was increased in Casp2−/− mice and was maintained into adulthood. By 17 weeks of age, Casp2−/− mice had reduced white adipose mass, smaller white adipocytes decreased fasting blood glucose and plasma triglycerides but maintained normal insulin levels. When placed on a 12-week high-fat diet (HFD), Casp2−/− mice resisted the development of obesity, fatty liver, hyperinsulinemia and insulin resistance. In addition, HFD-fed Casp2−/− mice had reduced white adipocyte hypertrophy, apoptosis and expansion of both subcutaneous and visceral adipose depots. Increased expression of UCP1 and the maintenance of adiponectin levels in white adipose tissue of HFD-fed Casp2−/− mice indicated increased browning and adipocyte hyperplasia. We found that while the preference for whole-body carbohydrate utilisation was maintained, HFD-fed Casp2−/− mice were not impaired in their ability to switch to utilising fats as a fuel source. Our findings suggest that caspase-2 impacts basal energy metabolism by regulating adipocyte biology and fat expansion, most likely via a non-apoptotic function. Furthermore, we show that caspase-2 deficiency shifts the balance in fuel choice towards increased carbohydrate utilisation and propose that this is due to mild energy stress. As a consequence, Casp2−/− mice show an adaptive remodelling of adipose tissue that protects from HFD-induced obesity and improves glucose homeostasis while paradoxically increasing their susceptibility to oxidative stress induced damage and premature ageing.

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Highlights: We present a methodology for systematic delineation of the C57BL/6J mouse cerebellum in MRI.  We have successfully delineated 38 cerebellar and cerebellar-related structures.  We have calculated average region volumes and created probabilistic maps for each structure. Keywords AbstractThe C57BL mouse is the centrepiece of efforts to use gene-targeting technology to understand cerebellar pathology, thus creating a need for a detailed magnetic resonance imaging (MRI) atlas of the cerebellum of this strain. In this study we present a methodology for systematic delineation of the vermal and hemispheric lobules of the C57BL/6J mouse cerebellum in magnetic resonance images. We have successfully delineated 38 cerebellar and cerebellar-related structures. The higher signal-to-noise ratio achieved by group averaging facilitated the identification of anatomical structures. In addition, we have calculated average region volumes and created probabilistic maps for each structure. The segmentation method and the probabilistic maps we have created will provide a foundation for future studies of cerebellar disorders using transgenic mouse models.

The composition of the gut microbiota following early-life antibiotic exposure affects host health and longevity in later life Graphical abstract Highlights d Analysis of aged mice exposed to antibiotics in the preweaning period d Microbiota community type following antibiotics affects host health in later life d PAM II mice have increased insulin resistance, inflammaging, and reduced lifespan

Inflammatory bowel disease (IBD) is a chronic relapsing and remitting inflammatory disease of the gastrointestinal tract. The diagnosis and monitoring of IBD are reliant on endoscopy, which is invasive and does not provide information on specific mediators. Symptom flare in IBD is associated with increased activation of innate immune pathways. Immuno-PET approaches have previously demonstrated the ability to detect colitis; however, a direct comparison of antibodies targeted to innate immune mediators and cells has not been done. We aimed to compare immuno-PET of antibodies to IL-1β and CD11b against standard 18 F-FDG and MRI approaches to detect colonic inflammation. Methods: Colonic concentrations of IL-1β and myeloperoxidase were determined by ELISA, and colonic infiltration by CD11b-positive CD3-negative innate immune cells was determined by flow cytometry and compared between healthy and dextran sodium sulphate-treated colitic mice. PET of 89 Zr-lα-IL-1β, 89 Zr-α-CD11b, and 18 F-FDG was compared by volume-of-interest analysis and with MRI by region-of-interest analysis. Imaging results were confirmed by ex vivo biodistribution analysis. Results: Colonic inflammation was associated with impaired colonic epithelial barrier permeability, increased colonic IL-1β and myeloperoxidase concentrations, and increased CD11b-positive CD3-negative innate immune cell infiltration into the colon. 89 Zr-α-IL-1β and 89 Zr-α-CD11b immuno-PET detected colonic inflammation, as did 18 F-FDG, and all PET tracers were more sensitive than MRI. Although 18 F-FDG volumes of interest correlated with colitis severity and a strong trend was observed with 89 Zr-α-IL-1β, no correlation was observed for 89 Zr-α-CD11b or MRI. 89 Zr-α-IL-1β was distributed mainly to the gastrointestinal tract, whereas 89 Zr-α-CD11b was distributed to more tissue types. Conclusion: Immuno-PET using antibodies directed to innate immune markers detected colonic inflammation, with 89 Zr-α-IL-1β providing a more tissue-specific signal than 89 Zr-α-CD11b. Development of these technologies for human subjects will potentially provide a less invasive approach than endoscopy for diagnosing and monitoring IBD. Detects Inflammation inβ Immuno-PET of Innate Immune Markers CD11b and IL-1 http://jnm.snmjournals.org/content/60/6/858 This article and updated information are available at: http://jnm.snmjournals.org/site/subscriptions/online.xhtml Information about subscriptions to JNM can be found at: http://jnm.snmjournals.org/site/misc/permission.xhtml

AbbreviationsChAT: Choline acetyl transferase dMRI: diffusion MRI FA: fractional anisotropy MCI: mild cognitive impairment MRI: magnetic resonance imaging p75 NTR : p75 neurotrophin receptor PB: phosphate buffer PBS: phosphate buffered saline ROI: region of interest SAP: saporin KeywordsCholinergic basal forebrain, tractography, p75 neurotrophin receptor, MRI, diffusion weighted imaging, neurodegeneration 3

In a genetic epilepsy model that is both seizure-naive and carries an allele for febrile seizure susceptibility, we have determined hippocampal structural changes that may be applied as a biomarker for seizure susceptibility.