Dim Light at Night Disturbs Molecular Pathways of Lipid Metabolism

Okuliarova, Monika; Rumanova, Valentina Sophia; Stebelová, Katarína; Zeman, Michal

doi:10.3390/ijms21186919

Cited by 19 publications

(21 citation statements)

References 60 publications

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“…Here, we explored a potential circadian-dependent immunomechanism that can link dLAN to negative health consequences. Indeed, recently we reported dLAN-induced health risks by increased hepatic lipid accumulation in dLANexposed rats (24). In the current study, we tested the hypothesis that chronic exposure to low-intensity light at night (~2 lx) compromises the circadian system, leading to disturbances in the daily variation of circulating immune cells and leukocyte movement into the renal cortex under homeostatic conditions.…”

Section: Introductionmentioning

confidence: 88%

Dim Light at Night Impairs Daily Variation of Circulating Immune Cells and Renal Immune Homeostasis

et al. 2021

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Dim light at night (dLAN) has become a pervasive part of the modern world, and growing evidence shows its association with increased health risks. Though this link is attributed to a disturbed circadian clock, the underlying mechanisms that can explain how circadian disruption from dLAN causes negative health effects remain unclear. Here, we exposed rats to a light–dark cycle (12:12 h) with low-intensity light at night (~2 lx) for 2 and 5 weeks and explored the steady-state pattern of circulating immune cells and renal immune-related markers, which are well controlled by the circadian clock. After 5 weeks, dLAN impaired the daily variation in several types of white blood cells, especially monocytes and T cells. Two-week dLAN caused a reduction in blood monocytes and altered gene expression of macrophage marker Cd68 and monocyte-attracting chemokine Ccl2 in the kidney. Interestingly, dLAN decreased renal 3-nitrotyrosine levels and resulted in up-regulation of the main endogenous antioxidant pathways, indicating a disturbance in the renal redox balance and an activation of compensatory mechanisms. These effects paralleled the altered renal expression of the molecular clock components and increased plasma corticosterone levels. Together, our results show that chronic exposure to dLAN weakened the circadian control of daily variation of circulating immune cells and disturbed renal immune and redox homeostasis. Consequences of this dLAN-disturbed immune balance on the ability of the immune system to cope with other challenges should by clarified in further studies.

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Section: Introductionmentioning

confidence: 88%

Dim Light at Night Impairs Daily Variation of Circulating Immune Cells and Renal Immune Homeostasis

et al. 2021

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“…The altered body mass in mice was predominantly explained by the increased daytime food intake ( Fonken et al, 2010 ). The daily pattern of food intake was altered also in rats, but without the increased body weight and fat mass ( Stenvers et al, 2016 ; Okuliarova et al, 2020 ; Okuliarova et al, 2022 ). These latter results from rats are in line with our current study, and we suggest that this species differences can be caused either by differences in light sensitivity or the study designs, for instance the different photoperiods used (14:10 LD cycle in mice and 12:12 LD cycle in rats).…”

Section: Discussionmentioning

confidence: 99%

“…In Swiss Webster mice, exposure to 5 lux during the dark-time resulted in the development of obesity accompanied by elevated daytime food intake and the impairment of glucose tolerance ( Fonken et al, 2010 ; Fonken et al, 2013 ). In rats, similar lighting conditions did not affect body weight, but did disturb the circadian control of sleep ( Stenvers et al, 2016 ) and deposition of lipids to the liver ( Rumanova et al, 2019 ; Okuliarova et al, 2020 ). In our recent study, we showed that dim ALAN suppresses daily rhythms of clock genes and vasopressin in the central oscillator and resulted in altered rhythms in hormonal outputs, and food and water intake ( Okuliarova et al, 2022 ).…”

Section: Introductionmentioning

confidence: 99%

Exposure to dim light at night alters daily rhythms of glucose and lipid metabolism in rats

et al. 2022

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Nocturnal light pollution has been rapidly increasing during the last decades and even though dim artificial light at night (ALAN) has been associated with metabolic diseases, its mechanism is still far from clear. Therefore, the aim of our study was to thoroughly analyze the effects of ALAN on energy metabolism, metabolites, metabolic hormones, and gene expression. Male Wistar rats were kept in either the standard light:dark (12:12) cycle or exposed to ALAN (∼2 lx) during the whole 12-h dark phase for 2 weeks. Energy metabolism was measured in metabolic cages. In addition, we measured plasma and hepatic metabolites, clock and metabolic gene expression in the liver and epididymal adipose tissue, and plasma hormone levels. In ALAN rats, we observed an unexpected transitory daytime peak of locomotor activity and a suppression of the peak in locomotor activity at the beginning of the dark period. These changes were mirrored in the respiratory exchange ratio. Plasma metabolites became arrhythmic, and plasma and hepatic cholesterol levels were increased. Lost rhythmicity of metabolites was associated with disrupted behavioral rhythms and expression of metabolic genes. In the liver, the rhythms of metabolic sensors were either phase-advanced (Ppara, Pgc1a, Nampt) or arrhythmic (Sirt1, Lxra) after ALAN. The rhythmic pattern of Ppara and Sirt1 was abolished in the adipose tissue. In the liver, the amplitude of the daily rhythm in glycogen content was attenuated, the Glut2 rhythm was phase-advanced and Foxo1 lost its daily rhythmicity. Moreover, hepatic Foxo1 and Gck were up-regulated after ALAN. Interestingly, several parameters of lipid metabolism gained rhythmicity (adiponectin, Hmgcs2, Lpl, Srebf1c) in the liver, whereas Noct became arrhythmic in the adipose tissue. Peripheral clock genes maintained their robust oscillations with small shifts in their acrophases. Our data show that even a low level of ALAN can induce changes in the daily pattern of behavior and energy metabolism, and disturb daily rhythms of genes encoding key metabolic sensors and components of metabolic pathways in the liver and adipose tissue. Disturbed metabolic rhythms by ALAN could represent a serious risk factor for the development and progression of metabolic diseases.

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“…Lipid metabolism is entwined with the circadian machinery, and its alterations are closely associated with circadian disruption [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. One factor that causes deterioration in circadian rhythms is glaucomatous damage to retinal ganglion cells (RGCs), which compromises light perception and signal transduction to the master clock (suprachiasmatic nuclei in the brain).…”

Section: Introductionmentioning

confidence: 99%

“…RGC damage was found to be associated with disrupted local [16,17] and systemic [18][19][20][21] circadian rhythms, as well as sleep [22,23]. Circadian rhythms of lipid metabolism are modulated by light and food [5][6][7][8][9][10][11][12][13][14][15]. Furthermore, light and the extent of the day-night intensity differences modulate chronotype, sleep parameters, and circadian alignment [24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Daytime Lipid Metabolism Modulated by CLOCK Gene Is Linked to Retinal Ganglion Cells Damage in Glaucoma

et al. 2022

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Lipid metabolism is intimately linked to circadian mechanisms and light signaling. Deteriorated photic transduction because of retinal ganglion cell (RGC) loss occurring with glaucoma progression reduces perceived light amplitude, causing circadian disruption. To investigate associations with RGCs, total cholesterol (TC), its low-density (LDL-C) and high-density (HDL-C) fractions, and triglycerides (TG) were measured, under a controlled meal regimen, during daytime hours in 114 patients diagnosed with primary open-angle glaucoma (POAG). RGC damage was assessed by high-definition optical coherence tomography (HD-OCT). Analysis of eight clock, clock-related, and melatonin receptor gene polymorphisms was performed on 19 patients. RGC loss was associated with changes in lipid metabolism in a time-dependent manner. Morning (08:00) values of HDL-C (r = 0.613, p < 0.0001) and TG (r = 0.568, p < 0.0001) correlated positively with RGC global loss, while LDL-C at 08:00 had a weak correlation (r = 0.235; p = 0.012) but showed a strong correlation in the evening (20:00) (r = 0.533, p < 0.0001). The morning–evening gradients (MEGs, changes at 20:00 versus 08:00) in TC and LDL-C changed sign from a negative to a positive association in patients exceeding the 15% two-eye mean GLV threshold. MEG (LDL-C higher in the evening than in the morning) was positive only in POAG patients with the CLOCK_3111 TT genotype.

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Dim Light at Night Disturbs Molecular Pathways of Lipid Metabolism

Cited by 19 publications

References 60 publications

Dim Light at Night Impairs Daily Variation of Circulating Immune Cells and Renal Immune Homeostasis

Dim Light at Night Impairs Daily Variation of Circulating Immune Cells and Renal Immune Homeostasis

Exposure to dim light at night alters daily rhythms of glucose and lipid metabolism in rats

Daytime Lipid Metabolism Modulated by CLOCK Gene Is Linked to Retinal Ganglion Cells Damage in Glaucoma

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