Volume 5 Issue 7, July 2023

Growing evidence demonstrates the metabolic benefits of repeated cold exposure in humans. Here, we argue that skeletal muscle thermogenesis, rather than the stimulation of thermogenic adipose tissue, is required to elicit these benefits in humans.

How photosynthetic microbes regulate CO₂ fixation and carbon metabolism in response to fluctuating environments is of fundamental and industrial relevance. In this issue, Lu et al. uncover a cryptic enzymatic function that accelerates the shutdown of the Calvin cycle under a transition into the dark.

An elegant quantitative analysis of brown fat and skeletal muscle metabolite flux reveals unpredicted fuel usage during thermogenesis, which suggests that brown fat predominantly uses glucose and lactate and acts as a nitrogen scavenger.

Time-restricted eating, a form of intermittent fasting, has shown promise in promoting metabolic health. In mice, limiting food accessibility only to the active cycle reduces body weight and improves glucose homeostasis; now, Xin et al. show that restricting feeding to the resting period increases their running performance.

This study shows that a 10% weight loss induced by calorie restriction and multimodal exercise training results in a much greater increase in whole-body insulin sensitivity than matched weight loss induced by calorie restriction alone. This result underscores the importance of adding regular exercise to a weight loss programme, as it improves metabolic health.

This study reveals that oxidative aneuploid cancer cells exhibit an upsurge of NADPH levels during mitosis, which neutralizes excessive reactive oxygen species and protects against chromosome mis-segregation.

Lynch and colleagues give an overview of the classical roles of the cytokine IL-17 in host immunity, and look deeper into the emerging roles of IL-17 in cross-talk between the nervous system and gut and how IL-17 regulates and is regulated by systemic metabolic processes.

Cook and colleagues discuss the nature of hepatic insulin resistance and argue that liver hyperinsulinization (excessive hepatic insulin action) is a driver of hepatic steatosis.

Marine cyanobacteria contribute to global carbon balance by fixing CO₂ and the shift between CO₂ fixation and ATP production requires fine-tuning its metabolic fluxes to light–dark cycles. These cycles can be very short in marine environments due to sea currents and fast adaptation is key to avoid futile cycles. In this study, Lu et al. provide a mechanistic insight into how this process is tightly regulated.

Propionate addition is a common strategy for production of valuable polyketides by supplying the substrate methylmalonyl-CoA in the industrial microbe Corynebacterium glutamicum; however, propionate inhibits C. glutamicum growth, thus hampering polyketide production. In this study, Zhan et al. identify the reasons for propionate-elicited growth inhibition and metabolically engineer C. glutamicum to circumvent this roadblock and increase polyketide production.

In aneuploid cancer cells with high ROS levels, a mitotic NADPH upsurge is required for error-free mitosis and tumour progression and therefore constitutes a cell cycle-dependent metabolic vulnerability.

In this study, Qian et al. identify a crosstalk between branched-chain amino acid metabolism and cell growth and motility through RhoC. Their work shows how enhanced BCAT1 activity, as identified by a mutation enriched in gastric cancer, leads to increased production of a metabolite that activates RhoC signaling.

A molecular mechanism is revealed through which commensal bacteria modulate intestinal epithelial barrier function.

Barreby et al. identify a distinct subpopulation of human resident liver myeloid cells that expresses factors that act in a protective fashion against oxidative stress associated with NAFLD.

In this study, Park, Haley, Le, Jung et al. perform a detailed characterization in vivo of metabolic flux distribution during thermogenesis and uncover brown fat nutrient fluxes and unexpected inter-organ metabolic crosstalk and glutamine utilization.

Beals, Kayser et al. demonstrate that exercise, in conjunction with diet-induced weight loss, causes greater improvement in whole-body insulin sensitivity than matched diet-induced weight loss alone in people with obesity and prediabetes.

Time-restricted feeding in the resting period is a potent dietary regimen to enhance running endurance in mice, by synchronizing rhythms of perilipin-5 in muscle tissues through involvement of the circadian clock.