Light at night disrupts diel patterns of cytokine gene expression and endocrine profiles in zebra finch (Taeniopygia guttata)

Mishra, Ila; Knerr, Reinhard M.; Stewart, Alexander A.; Payette, Wesley I.; Richter, Melanie; Ashley, Noah T.

doi:10.1038/s41598-019-51791-9

Cited by 43 publications

(22 citation statements)

References 73 publications

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“…Nocturnal MEL levels under ALAN conditions were significantly lower compared to control birds that were exposed to dark nights ( Figure 4 ), similar to previous reports in zebra finches [ 8 , 47 ], as well as in other bird species [ 23 ], diurnal mammals [ 48 ], and fish [ 49 ]. Evidently, very low ALAN intensities can suppress MEL biosynthesis not only in nocturnal [ 50 ], but also in diurnal species.…”

Section: Discussionsupporting

confidence: 89%

Artificial Light at Night Increases Recruitment of New Neurons and Differentially Affects Various Brain Regions in Female Zebra Finches

Moaraf

Heiblum

Vistoropsky

et al. 2020

IJMS

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Despite growing evidence that demonstrate adverse effects of artificial light at night (ALAN) on many species, relatively little is known regarding its effects on brain plasticity in birds. We recently showed that although ALAN increases cell proliferation in brains of birds, neuronal densities in two brain regions decreased, indicating neuronal death, which might be due to mortality of newly produced neurons or of existing ones. Therefore, in the present study we studied the effect of long-term ALAN on the recruitment of newborn neurons into their target regions in the brain. Accordingly, we exposed zebra finches (Taeniopygia guttata) to 5 lux ALAN, and analysed new neuronal recruitment and total neuronal densities in several brain regions. We found that ALAN increased neuronal recruitment, possibly as a compensatory response to ALAN-induced neuronal death, and/or due to increased nocturnal locomotor activity caused by sleep disruption. Moreover, ALAN also had a differential temporal effect on neuronal densities, because hippocampus was more sensitive to ALAN and its neuronal densities were more affected than in other brain regions. Nocturnal melatonin levels under ALAN were significantly lower compared to controls, indicating that very low ALAN intensities suppress melatonin not only in nocturnal, but also in diurnal species.

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Section: Discussionsupporting

confidence: 89%

Artificial Light at Night Increases Recruitment of New Neurons and Differentially Affects Various Brain Regions in Female Zebra Finches

Moaraf

Heiblum

Vistoropsky

et al. 2020

IJMS

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“…Related to a possibly exaggerated inflammatory response, total leukocytes were positively associated with parasite intensity regardless of time lag, whereas control birds showed more acute synchrony with parasitemia. Notably, we observed these immunological effects at a lower light intensity (2.5 lux) than similar studies (e.g., 5 to 400 lux) [8][9][10][11]13,47], suggesting that chronic exposure to even dim ALAN could cause immune dysregulation. However, further quantification of immune gene expression would help identify the specific pathways by which ALAN affects reactivation of haemosporidian infection [51].…”

Section: Discussioncontrasting

confidence: 55%

“…In mice, ALAN can induce an exaggerated inflammatory response driven by proinflammatory cytokines, excessive production of which causes immunopathology and can limit control of infection [10,11]. Similarly, zebra finches (Taeniopygia guttata) exposed to ALAN also displayed neuroinflammation with these cytokines [47]. The mechanisms by which the avian immune system controls haemosporidians remains unclear [48], but adaptive responses are likely also important [49,50].…”

Section: Discussionmentioning

confidence: 99%

Artificial light at night amplifies seasonal relapse of haemosporidian parasites in a widespread songbird

Becker

Singh

Pan

et al. 2020

Preprint

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14Urban habitats can shape interactions between hosts and parasites by altering within-host 15 processes such as resistance. Artificial light at night is common in urban environments, and 16 chronic exposure can impair host immunity in ways that may increase infection. However, 17 studies of causal links between this stressor, immunity, and infection dynamics are rare, 18 particularly in migratory animals. Here, we experimentally tested how artificial light at night 19 affects cellular immunity and haemosporidian parasite intensity across the annual cycle of 20 migrant and resident subspecies of the dark-eyed junco (Junco hyemalis). We monitored an 21 experimental group exposed to light at night and a control group under nighttime darkness as 22 they passed through short days simulating early spring to longer days simulating the breeding 23 season, followed by fall migration. Using generalized additive models, we show that artificial 24 light at night increased inflammation, and leukocyte counts were greatest in early spring and fall. 25At the start of the experiment, few birds had active infections based on microscopy, but PCR 26 revealed many birds had chronic infections. Artificial light at night increased parasitemia across 27 the annual cycle, with strong peaks in spring and fall that were largely absent in control birds. As 28 birds were kept in indoor aviaries to prevent vector exposure, this increased parasitemia indicates 29 relapse of chronic infection during costly life history stages (i.e., reproduction). Although the 30 immunological and parasitological time series were in phase for control birds, cross-correlation 31 analyses also revealed artificial light at night desynchronized leukocyte profiles and parasitemia, 32 which could suggest a general exaggerated inflammatory response. Our study shows how a 33 common anthropogenic influence can shape within-host processes to affect infection dynamics. 34 35 As suburban and urban habitats expand globally, certain species are attracted to these 36 environments owing to a combination of altered microclimate, predation risk, and resource 37 availability [1,2]. Such changes in biotic and abiotic conditions can have cascading and complex 38 effects on wildlife [3,4]. When considering infectious disease, urban habitats can shape the 39 interactions between hosts and parasites by altering within-host processes such as resistance or 40 tolerance [5]. Understanding how urbanization affects these processes is especially important, as 41 it can facilitate novel cross-species transmission opportunities between various host species [6]. 42 One aspect of urban habitats that could have strong effects on these within-host processes 43 is artificial light at night (ALAN). By altering animal circadian rhythms, ALAN can cause a suite 44 of physiological changes relevant to infection [7]. In particular, chronic exposure to ALAN can 45 suppress various aspects of host immune function, including cellular response and microbial 46killing ability [8,9]. Prolonged ambient lig...

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“…Accumulating results indicate a tight circadian control of the immune system, including regulating the activity and controlling the movement of innate immune cells (reviewed in Scheiermann et al, 2018 ). Specifically, experimental ALAN exposure led to the abolishment of rhythmic expression of immune genes in different tissues of zebra finches, Taeniopygia guttata ( Mishra et al, 2019 ). Thus, the disruption of the diel physiological homeostasis by ALAN is likely to negatively affect health and could ultimately decrease fitness.…”

Section: Introductionmentioning

confidence: 99%

Exposure to artificial light at night alters innate immune response in wild great tit nestlings

Ziegler

Watson

Hegemann

et al. 2021

Journal of Experimental Biology

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The large-scale impact of urbanization on wildlife is rather well documented, however the mechanisms underlying the effects of urban environments on animal physiology and behaviour are still poorly understood. Here, we focused on one major urban pollutant - artificial light at night (ALAN) - and its effects on the capacity to mount an innate immune response in wild great tit Parus major nestlings. Exposure to ALAN alters circadian rhythms of physiological processes, by disrupting the nocturnal production of the hormone melatonin. Nestlings were exposed to a light source emitting 3 lux for seven consecutive nights. Subsequently, nestlings were immune-challenged with a lipopolysaccharide injection, and we measured haptoglobin and nitric oxide levels pre- and post-injection. Both haptoglobin and nitric oxide are important markers for innate immune function. We found that ALAN exposure altered the innate immune response, with ALAN nestlings having lower haptoglobin and higher nitric oxide levels after the immune-challenge compared to dark-night nestlings. Unexpectedly, nitric oxide levels were overall, lower after the immune-challenge than before. These effects were likely mediated by melatonin, since ALAN-treated birds had on average 49% lower melatonin levels than the dark-night birds. ALAN exposure did not have any clear effects on nestling growth. This study provides a potential physiological mechanism underlying the documented differences in immune function between urban and rural birds observed in other studies. Moreover, it gives evidence that ALAN exposure affects nestling physiology, potentially causing long-term effects on physiology and behaviour, which ultimately can affect their fitness.

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Light at night disrupts diel patterns of cytokine gene expression and endocrine profiles in zebra finch (Taeniopygia guttata)

Cited by 43 publications

References 73 publications

Artificial Light at Night Increases Recruitment of New Neurons and Differentially Affects Various Brain Regions in Female Zebra Finches

Artificial Light at Night Increases Recruitment of New Neurons and Differentially Affects Various Brain Regions in Female Zebra Finches

Artificial light at night amplifies seasonal relapse of haemosporidian parasites in a widespread songbird

Exposure to artificial light at night alters innate immune response in wild great tit nestlings

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