Biology subjects

Schonke, M.

Publications and source records attributed to Schonke, M..

3 recordsLinked to original sources

bioRxiv2024

Exercise training at different intensities induces heat stress, disrupts barrier function and alters microbiota in the gut of mice

Exercise is generally beneficial for health but strenuous exercise can have detrimental effects on the gastrointestinal tract. The combination of ischemia and heat shock during exercise is a crucial contributor to intestinal epithelial damage. Growing evidence points towards an important regulatory role of gut microbes in intestinal homeostasis. Here, we characterize and compare the effects of moderate and vigorous exercise training on intestinal epithelial damage, stress response, inflammatory response, and gut microbiota alterations in mice and investigate the mechanisms underlying exercise-induced intestinal injury. Exercise training for six weeks caused heat stress in the intestine, resulting in the disruption of the intestinal epithelial barrier and local inflammation. This was characterized by increased colonic HSP-70 and HSF-1 protein expression, increased epithelial permeability, decreased colonic expression of tight junction proteins ZO-1 and occludin and intestinal morphological changes. Daily moderate exercise training caused hereby more severe injury than vigorous training on alternating days. Furthermore, exercise training altered the gut microbiota profile. The abundance of Lactobacillaceae was reduced, potentially contributing to the deteriorated intestinal status, while the abundance of short-chain fatty acid-producing Lachnospiraceae was increased, especially following vigorous training. This increase in short-chain fatty acid-producing bacteria following vigorous training possibly counteracted the impairment of the intestinal barrier function. In summary, exercise disrupts the intestinal barrier function, with vigorous exercise training with intermittent rest days being less damaging than daily moderate exercise training.

physiology↗

bioRxiv2022

Time to run: Late rather than early exercise training in mice remodels the gut microbiome and reduces atherosclerosis development

The metabolic and inflammatory processes that are implicated in the development of cardiovascular diseases are under control of the biological clock. While skeletal muscle function exhibits circadian rhythms, it is unclear to what extent the beneficial health effects of exercise are restricted to unique time windows. We aimed to study whether the timing of exercise training differentially modulates the development of atherosclerosis and elucidate underlying mechanisms. We endurance-trained atherosclerosis-prone female APOE*3-Leiden.CETP mice fed a Western-type diet, a well-established human-like model for cardiometabolic diseases, for one hour five times a week for four weeks either in their early or in their late active phase on a treadmill. We monitored metabolic parameters, the development of atherosclerotic lesions in the aortic root and assessed the composition of the gut microbiota. Late, but not early, exercise training reduced fat mass by 19% and the size of early-stage atherosclerotic lesions by as much as 29% compared to sedentary animals. No correlation between cholesterol exposure and lesion size was evident, as no differences in plasma lipid levels were observed, but circulating levels of the pro-inflammatory markers ICAM-1 and VCAM-1 were reduced with late exercise. Strikingly, we observed a time-of-day-dependent effect of exercise training on the composition of the gut microbiota as only late training increased the abundance of gut bacteria producing short-chain fatty acids with proposed anti-inflammatory properties. Together, these findings indicate that timing is a critical factor to the beneficial anti-atherosclerotic effects of exercise with a great potential to further optimize training recommendations for patients.

physiology↗

bioRxiv2022

Early but not late exercise training in mice exacerbates hepatic inflammation in early NAFLD

Exercise effectively prevents obesity-related disorders, but it is unclear whether the beneficial health effects of exercise are restricted to unique circadian windows. Therefore, we aimed to study whether timing of exercise training differentially modulates the development and progression of non-alcoholic fatty liver disease (NAFLD), a disease currently estimated to affect over two billion people worldwide. We endurance-trained high fat-high cholesterol-fed NAFLD-prone male APOE*3-Leiden.CETP mice five times per week for eight weeks either in the early (ZT13) or in the late (ZT22) active phase and assessed the NAFLD score (histology) and hepatic inflammation compared to sedentary mice. Exercise training prevented an increase in body fat mass and fasting plasma glucose as expected, but neither early nor late training affected liver triglyceride or cholesterol content compared to sedentary mice, likely due to a very early stage of hepatic steatosis. In line, hepatic expression of de novo lipogenesis genes (e.g., Fasn, Srebp1c) was similarly downregulated by early and late training. However, exercise had a distinct time-dependent effect on hepatic inflammation, as only early training promoted an influx of pro-inflammtory cells into the liver paired with increased expression of the pro-inflammatory cytokines (e.g. Tnfa, Il1b). This data suggests that the timing of exercise is a critical factor for the effect on cardiometabolic disease development.

molecular biology↗