Parental cardiorespiratory fitness influences early life energetics and metabolic health.

High cardiorespiratory fitness (CRF) is associated with a reduced risk of metabolic disease and is linked to superior mitochondrial respiratory function. This study investigated how intrinsic CRF affects bioenergetics and metabolic health in adulthood and early life. Adult rats selectively bred for low and high running capacity [low capacity runners (LCR) and high capacity runners (HCR), respectively] underwent metabolic phenotyping before mating. Weanlings were evaluated at 4-6 wk of age, and whole body energetics and behavior were assessed using metabolic cages. Mitochondrial respiratory function was assessed in permeabilized tissues through high-resolution respirometry. Proteomic signatures of adult and weanling tissues were determined using mass spectrometry. The adult HCR group exhibited lower body mass, improved glucose tolerance, and greater physical activity compared with the LCR group. The adult HCR group demonstrated higher mitochondrial respiratory capacities in the soleus and heart compared with the adult LCR group, which coincided with a greater abundance of proteins involved in lipid catabolism. HCR and LCR weanlings had similar body mass, but HCR weanlings displayed reduced adiposity. In addition, HCR weanlings exhibited better glucose tolerance and higher physical activity levels than LCR weanlings. Higher respiratory capacities were observed in the soleus, heart, and liver tissues of HCR weanlings compared with LCR weanlings, which were not owed to greater mitochondrial content. Proteomic analyses indicated a greater potential for lipid oxidation in the contractile muscles of HCR weanlings. In conclusion, offspring born to parents with high CRF possess an enhanced capacity for lipid catabolism and oxidative phosphorylation, thereby influencing metabolic health. These findings highlight that intrinsic CRF shapes the bioenergetic phenotype with implications for metabolic resilience in early life.NEW & NOTEWORTHY Inherited cardiorespiratory fitness (CRF) influences early life bioenergetics and metabolic health. Higher intrinsic CRF was associated with reduced adiposity and improved glucose tolerance in early life. This metabolic phenotype was accompanied by greater mitochondrial respiratory capacity in skeletal muscle, heart, and liver tissue. Proteomic profiling of these three tissues further revealed potential mechanisms linking inherited CRF to early life metabolism.

A modest change in housing temperature alters whole body energy expenditure and adipocyte thermogenic capacity in mice.

Typical vivarium temperatures (20-26°C) induce facultative thermogenesis in mice, a process attributable in part to uncoupling protein-1 (UCP1). The impact of modest changes in housing temperature on whole body and adipose tissue energetics in mice remains unclear. Here, we determined the effects of transitioning mice from 24°C to 30°C on total energy expenditure and adipose tissue protein signatures. C57BL/6J mice were housed at 24°C for 2 wk and then either remained at 24°C (n = 16/group, 8M/8F) or were transitioned to 30°C (n = 16/group, 8M/8F) for 4 wk. Total energy expenditure and its components were determined by indirect calorimetry. Interscapular brown adipose tissue (iBAT) and inguinal white adipose tissue (iWAT) proteins were quantified by Western blot and quantitative proteomics. Transitioning from 24°C to 30°C reduced total energy expenditure in both male (-25%) and female (-16%) mice, which was attributable to lower basal energy expenditure in males (-36%) and females (-40%). Total iBAT UCP1 protein content was 50% lower at 30°C compared with 24°C, whereas iWAT UCP1 protein content was similar between conditions. iBAT UCP1 protein content remained 20-fold greater than iWAT at 30°C. In iBAT and iWAT, 183 and 41 proteins were differentially expressed between 24°C and 30°C, respectively. iWAT proteins (257) differentially expressed between sexes at 30°C were not differentially expressed at 24°C. Thus, 30°C housing lowers total energy expenditure of mice when compared with an ambient temperature (24°C) that falls within the National Research Council's guidelines for housing laboratory mice. Lower iBAT UCP1 content accompanied chronic housing at 30°C. Furthermore, housing temperature influences sexual dimorphism in the iWAT proteome. These data have implications regarding the optimization of preclinical models of human disease.NEW & NOTEWORTHY Housing mice at 30°C reduced the basal and total energy expenditure compared with 24°C, which was accompanied by a reduction in brown adipose tissue UCP1 content. Proteomic profiling demonstrated the brown adipose tissue and white adipose tissue proteomes were largely influenced by housing temperature and sex, respectively. Therefore, 30°C housing revealed sexual dimorphism in the white adipose tissue proteome that was largely absent in animals housed at 24°C.

Significant role of IL-1 signaling, but limited role of inflammasome activation, in oviduct pathology during Chlamydia muridarum genital infection.

IL-1ß has been implicated in the development of oviduct pathology during Chlamydia muridarum genital infection in the mouse model. The goal of this study was to characterize the role of IL-1 signaling and the inflammasome-activation pathways during genital chlamydial infection. Compared with control mice, IL-1R-deficient mice displayed delayed clearance and increased chlamydial colonization. Consistent with the role for IL-1 signaling in infection clearance, mice deficient for the IL-1R antagonist cleared infection at a faster rate. Despite increased infection, IL-1R-deficient mice had significantly reduced oviduct pathology, which was associated with decreased numbers of neutrophils, but more macrophages, in the genital tract. IL-1ß secretion is dependent on caspase-1 and apoptosis-associated speck-like protein containing caspase recruitment domain (ASC) inflammasome during in vitro infection of primed macrophages with C. muridarum. To investigate the role of inflammasome components during in vivo genital infection, mice lacking NLRP3, NLRC4, and ASC were tested and found to display no reduction in oviduct pathology compared with control mice. Mice deficient for ASC displayed a prolonged course of infection, which was associated with reduced T cell recruitment and proliferation. Further, ASC-deficient mice displayed normal levels of IL-1ß in genital secretions. However, a significant decrease in caspase-1-dependent IL-18 was observed in both ASC- and NLRP3-deficient mice. These data demonstrate a major role for IL-1 signaling, but a limited role for the inflammasome pathway, in IL-1ß secretion and development of oviduct pathology during genital chlamydial infection. The data also suggest an IL-1-independent role for ASC in adaptive immunity during genital chlamydial infection.

Evaluation of a Plant-Based Infant Formula Containing Almonds and Buckwheat on Gut Microbiota Composition, Intestine Morphology, Metabolic and Immune Markers in a Neonatal Piglet Model.

A controlled-neonatal piglet trial was conducted to evaluate the impact of a plant-based infant formula containing buckwheat and almonds as the main source of protein compared to a commercially available dairy-based formula on the gut health parameters. Two day old piglets were fed either a plant-based or a dairy-based formula until day 21. Gut microbiome, cytokines, growth and metabolism related outcomes, and intestinal morphology were evaluated to determine the safety of the plant-based infant formula. This study reported that the plant-based formula-fed piglets had a similar intestinal microbiota composition relative to the dairy-based formula-fed group. However, differential abundance of specific microbiota species was detected within each diet group in the small and large intestinal regions and fecal samples. Lactobacillus delbrueckii, Lactobacillus crispatus, and Fusobacterium sp. had higher abundance in the small intestine of plant-based formula-fed piglets compared to the dairy-based group. Bacteroides nordii, Enterococcus sp., Lactobacillus crispatus, Prevotella sp., Ruminococcus lactaris, Bacteroides nordii, Eisenbergiella sp., Lactobacillus crispatus, Prevotella sp., and Akkermansia muciniphila had greater abundance in the large intestine of the plant based diet fed piglets relative to the dairy-based diet group. In the feces, Clostridiales, Bacteroides uniformis, Butyricimonasvirosa, Cloacibacillus porcorum, Clostridium clostridioforme, and Fusobacterium sp. were abundant in dairy-based group relative to the plant-based group. Lachnospiraceae, Clostridium scindens, Lactobacillus coleohominis, and Prevetolla sp. had greater abundance in the feces of the plant-based group in comparison to the dairy-based group. Gut morphology was similar between the plant and the dairy-based formula-fed piglets. Circulatory cytokines, magnesium, triiodothyronine (T3), thyroxine (T4), thyroid stimulating hormone (TSH), vitamin D, vitamin K, and IgE levels were similar among all piglets independent of dietary group. Overall, the present study demonstrated that a plant-based formula with buckwheat and almonds as the primary source of protein can support similar gut microbiota growth and health outcomes compared to a dairy-based infant formula.

Evaluation of the Safety of a Plant-Based Infant Formula Containing Almonds and Buckwheat in a Neonatal Piglet Model.

A randomized neonatal piglet trial was conducted to evaluate the safety and the effects of a plant-based formula containing almonds and buckwheat as the main ingredients on growth and plasma parameters. From postnatal day (PND) 2 to 21, the piglets were fed a dairy-based milk formula (Similac Advance) or a plant-based formula (Else Nutrition) and all piglets were euthanized at day 21. No diarrhea was observed after PND 8 and all the piglets completed the trial. Body growth, kcal intake, the complete plasma count parameters and hematological parameters were within the reference range in both groups. Organ growth and development was similar between the two groups. Plasma glucose was higher in the dairy-based-fed piglets relative to the plant-based at 2 weeks of age. Liver function biomarkers levels were greater in the plasma of the plant-based compared to the dairy-based fed group. In addition, calcium levels were higher in the plant-based fed piglets at 1 week of age. Thus, the plant-based formula tested in this study was well tolerated by the piglets and supported similar growth compared to dairy-based milk formula. Therefore, the results support the safety of the tested plant-based infant formula during the neonatal period in comparison to the dairy-based formula fed group.

Interferon regulatory transcription factor 3 protects mice from uterine horn pathology during Chlamydia muridarum genital infection.

Mice with the type I interferon (IFN) receptor gene knocked out (IFNAR KO mice) or deficient for alpha/beta IFN (IFN-α/ß) signaling clear chlamydial infection earlier than control mice and develop less oviduct pathology. Initiation of host IFN-ß transcription during an in vitro chlamydial infection requires interferon regulatory transcription factor 3 (IRF3). The goal of the present study was to characterize the influence of IRF3 on chlamydial genital infection and its relationship to IFN-ß expression in the mouse model. IRF3 KO mice were able to resolve infection as well as control mice, overcoming increased chlamydial colonization and tissue burden early during infection. As previously observed for IFNAR KO mice, IRF3 KO mice generated a potent antigen-specific T cell response. However, in contrast to IFNAR KO mice, IRF3 KO mice exhibited unusually severe dilatation and pathology in the uterine horns but normal oviduct pathology after infection. Although IFN-ß expression in vivo was dependent on the presence of IRF3 early in infection (before day 4), the IFN-independent function of IRF3 was likely driving this phenotype. Specifically, early during infection, the number of apoptotic cells and the number of inflammatory cells were significantly less in uterine horns from IRF3 KO mice than in those from control mice, despite an increased chlamydial burden. To delineate the effects of IFN-ß versus IRF3, neutralizing IFN-ß antibody was administered to wild-type (WT) mice during chlamydial infection. IFN-ß depletion in WT mice mimicked that in IFNΑR KO mice but not that in IRF3 KO mice with respect to both chlamydial clearance and reduced oviduct pathology. These data suggest that IRF3 has a role in protection from uterine horn pathology that is independent of its function in IFN-ß expression.

Critical role for interleukin-1beta (IL-1beta) during Chlamydia muridarum genital infection and bacterial replication-independent secretion of IL-1beta in mouse macrophages.

Recent findings have implicated interleukin-1beta (IL-1beta) as an important mediator of the inflammatory response in the female genital tract during chlamydial infection. But how IL-1beta is produced and its specific role in infection and pathology are unclear. Therefore, our goal was to determine the functional consequences and cellular sources of IL-1beta expression during a chlamydial genital infection. In the present study, IL-1beta(-/-) mice exhibited delayed chlamydial clearance and decreased frequency of hydrosalpinx compared to wild-type (WT) mice, implying an important role for IL-1beta both in the clearance of infection and in the mediation of oviduct pathology. At the peak of IL-1beta secretion in WT mice, the major producers of IL-1beta in vivo are F4/80(+) macrophages and GR-1(+) neutrophils, but not CD45(-) epithelial cells. Although elicited mouse macrophages infected with Chlamydia muridarum in vitro secrete minimal IL-1beta, in vitro prestimulation of macrophages by Toll-like receptor (TLR) ligands such as lipopolysaccharide (LPS) purified from Escherichia coli or C. trachomatis L2 prior to infection greatly enhanced secretion of IL-1beta from these cells. By using LPS-primed macrophages as a model system, it was determined that IL-1beta secretion was dependent on caspase-1, potassium efflux, and the activity of serine proteases. Significantly, chlamydia-induced IL-1beta secretion in macrophages required bacterial viability but not growth. Our findings demonstrate that IL-1beta secreted by macrophages and neutrophils has important effects in vivo during chlamydial infection. Additionally, prestimulation of macrophages by chlamydial TLR ligands may account for the elevated levels of pro-IL-1beta mRNA observed in vivo in this cell type.

Genital Chlamydia infection in hyperlipidemic mouse models exacerbates atherosclerosis.

BACKGROUND AND AIMS: Atherosclerosis is a chronic inflammatory disease, and recent studies have shown that infection at remote sites can contribute to the progression of atherosclerosis in hyperlipidemic mouse models. In this report, we tested the hypothesis that genital Chlamydia infection could accelerate the onset and progression of atherosclerosis. METHODS: Apolipoprotein E (Apoe-/-) and LDL receptor knockout (Ldlr-/-) mice on a high-fat diet were infected intra-vaginally with Chlamydia muridarum. Atherosclerotic lesions on the aortic sinuses and in the descending aorta were assessed at 8-weeks post-infection. Systemic, macrophage, and vascular site inflammatory responses were assessed and quantified. RESULTS: Compared to the uninfected groups, infected Apoe-/- and Ldlr-/- mice developed significantly more atherosclerotic lesions in the aortic sinus and in the descending aorta. Increased lesions were associated with higher circulating levels of serum amyloid A-1, IL-1ß, TNF-α, and increased VCAM-1 expression in the aortic sinus, suggesting an association with inflammatory responses observed during C. muridarum infection. Genital infection courses were similar in Apoe-/-, Ldlr-/-, and wild type mice. Further, Apoe-/- mice developed severe uterine pathology with increased dilatations. Apoe-deficiency also augmented cytokine/chemokine response in C. muridarum infected macrophages, suggesting that the difference in macrophage response could have contributed to the genital pathology in Apoe-/- mice. CONCLUSIONS: Overall, these studies demonstrate that genital Chlamydia infection exacerbates atherosclerotic lesions in hyperlipidemic mouse and suggest a novel role for Apoe in full recovery of uterine anatomy after chlamydial infection.

Type I interferon signaling exacerbates Chlamydia muridarum genital infection in a murine model.

Type I interferons (IFNs) induced during in vitro chlamydial infection exert bactericidal and immunomodulatory functions. To determine the precise role of type I IFNs during in vivo chlamydial genital infection, we examined the course and outcome of Chlamydia muridarum genital infection in mice genetically deficient in the receptor for type I IFNs (IFNAR(-/-) mice). A significant reduction in chlamydial shedding and duration of lower genital tract infection was observed in IFNAR(-/-) mice in comparison to the level of chlamydial shedding and duration of infection in wild-type (WT) mice. Furthermore, IFNAR(-/-) mice developed less chronic oviduct pathology in comparison to that in WT mice. Compared to the WT, IFNAR(-/-) mice had a greater number of chlamydial-specific T cells in their iliac lymph nodes 21 days postinfection. IFNAR(-/-) mice also exhibited earlier and enhanced CD4 T-cell recruitment to the cervical tissues, which was associated with increased expression of CXCL9 in the genital secretions of IFNAR(-/-) mice, but not with expression of CXCL10, which was reduced in the genital secretions of IFNAR(-/-) mice. These data suggest that type I IFNs exacerbate C. muridarum genital infection through an inhibition of the chlamydial-specific CD4 T-cell response.