The Impact of Photoperiod on the Leptin Sensitivity and Course of Inflammation in the Anterior Pituitary

Wójcik, M.; Herman, Andrzej Przemysław; Zieba, D; Krawczyńska, Agata

doi:10.3390/ijms21114153

Cited by 7 publications

(10 citation statements)

References 109 publications

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“…Our study showed that there are significant differences between the effect of an acute and prolonged LPS-treatment on the gene expression of proinflammatory cytokines and their receptors in the ovine anterior pituitary. It was found that a single LPS injection increased the transcription of all examined cytokines, which is similar to other experiments conducted on sheep [ 28 ]. In contrast to acute inflammation when the gene expression of all examined cytokines was increased (the transcription of IL-6 and IL-1β was increased more than TNFα ), prolonged administration of bacterial endotoxin did not influence IL-1β and IL-6 gene expression in the anterior pituitary.…”

Section: Discussionsupporting

confidence: 88%

Effect of Acute and Prolonged Inflammation on the Gene Expression of Proinflammatory Cytokines and Their Receptors in the Anterior Pituitary Gland of Ewes

Wojtulewicz

Krawczyńska

Tomaszewska-Zaremba

et al. 2020

IJMS

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An acute and prolonged inflammation inhibits the reproduction process by the disruption of the neurohormonal activity of the hypothalamic-pituitary-gonadal axis. It is thought that these changes may be caused by proinflammatory cytokines, i.e., interleukin (IL) -1β, IL-6 and tumor necrosis factor (TNF) α. The aim of this study was to determine the effect of an acute and prolonged inflammation on the expression of genes encoding cytokine and their receptors, gonadotropin releasing hormone receptor (GnRHR), beta subunits of luteinizing hormone (LHβ) and follicle-stimulating (FSHβ) in the anterior pituitary (AP). Moreover, the circulating concentration of LH and FSH was also assayed. Two experiments were carried out on adult ewes which were divided into two control groups and treated with lipopolysaccharide (LPS; 400 ng / kg). Acute inflammation was caused by a single injection of LPS into the external jugular vein, while the chronic inflammation was induced by seven times LPS injection (one a day). In both experiments, animals were euthanized 3h after the last LPS / NaCl injection and the blood samples collected 15 min before euthanasia. An acute inflammation stimulates the expression of the IL-1β, IL-6 and TNFα genes and their receptors in the AP of sheep. Prolonged inflammation increased TNFα gene expression and both types of TNFα and IL-6 receptors. Both an acute and prolonged inflammation inhibited LHβ gene expression in the AP and reduced LH level in blood. A sevenfold LPS injection raises FSH concentration. The gene expression of GnRHR was reduced in the ovine AP only after a single injection of endotoxin. Our results suggest that there are important differences in the way how an acute and prolonged inflammation influence proinflammatory cytokines and their receptors gene expression in the AP of anestrous ewes, which could be reflected by differences in the AP secretory activity during these states.

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Section: Discussionsupporting

confidence: 88%

Effect of Acute and Prolonged Inflammation on the Gene Expression of Proinflammatory Cytokines and Their Receptors in the Anterior Pituitary Gland of Ewes

Wojtulewicz

Krawczyńska

Tomaszewska-Zaremba

et al. 2020

IJMS

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“…We observed a stronger LPS effect on TLR2, TLR4, IL1B, IL1R1, IL1R2, IL6 and TNFRSF1B expression under SD than LD. In the same ewes, a stronger response to LPS stimulation during SD than LD was also observed in the anterior pituitary (Wójcik et al, 2020).…”

Section: Discussionsupporting

confidence: 56%

“…In turn, in the anterior pituitary, only the expression of IL1B and IL1R2 was similar between LD and SD, while the expression of other cytokines and their receptors was higher under SD than LD (Wójcik et al, 2020).…”

Section: Discussionmentioning

confidence: 86%

Photoperiod alters the choroid plexus response to LPS-induced acute inflammation in EWES

Skipor

Szczepkowska

Kowalewska

et al. 2021

Annals of Animal Science

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This study determined the influence of photoperiod on the expression of toll-like receptor 2 and 4 (TLR2 and TLR4), interleukin 1□ (IL1B), IL-1 receptor type I (IL1R1) and II (IL1R2), interleukin 6 (IL6), the IL-6 receptor (IL6R) and signal transducer (IL6ST), tumor necrosis factor α (TNF), and TNF□ receptor type I (TNFRSF1A) and II (TNFRSF1B) in the choroid plexus (ChP) of ewes with lipopolysaccharide (LPS)-induced acute inflammation. Under short-days (SD, n = 12, anestrous) and long-days (LD, n = 12, synchronized follicular phase), ewes were treated with saline or LPS. Compared to LD conditions, the ewes under SD were characterized by a greater (P<0.05) area under the curve (AUC) of cortisol in the LPS-treated group and by a lower (P<0.05) AUC of prolactin in the saline-treated group. Under both photoperiods, LPS increased (P<0.05) the expression of all examined genes except for TNFRSF1B (only under SD), TNF and TNFRSF1A (no stimulation), and IL6R (decreased (P<0.05) under SD). The LPS-induced increases in TLR2, TLR4, IL1B and its receptors, IL6 and TNFRSF1B were higher (P<0.05) under SD than LD. TLR4 was positively correlated with IL1B and IL6 in both saline- (r2 = 0.64, P<0.01 and r2 = 0.52, P<0.01) and LPS-treated (r2 = 0.81, P<0.0001 and r2 = 0.51, P<0.001) ewes. IL1B (r2 = 0.56, P<0.01 and r2 = 0.77, P<0.0001) and IL6 (r2 = 0.77, P<0.005 and r2 = 0.35, P<0.05) were positively correlated with TLR2 in saline- and LPS-treated ewes, respectively. This indicates that in ewes, the ChP response to acute systemic inflammation is dependent upon the photoperiod with stronger effects being observed under SD. Our results also suggest that gonadal hormones altering TLR4 signaling events are involved in the photoperiodic modulation of the ChP response to LPS. Further experiments are required to explain the mechanism involved in this phenomenon.

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“…Leptin affected the mRNA expression of examined genes in the LPS-treated but not in the saline-treated sheep. In the physiological state, the effect of leptin seemed to be tissue-specific, since leptin significantly upregulated the expression of IL6 and IL1R2 in the aorta [ 45 ], IL1B , and IL1R2 in the perivascular adipose tissue (PVAT) [ 46 ] and IL1B , IL6 , IL6R and IL6ST in the anterior pituitary (AP) [ 47 ] collected from the same sheep. In the LPS-challenged conditions, we observed the synergistic effect of LPS and leptin on the expression of IL1B but only during SD, and IL1R2 , IL1RN , IL6ST , CCL2 and SOCS3 only during LD.…”

Section: Discussionmentioning

confidence: 99%

“…Interestingly, the lack of synergistic action of leptin and LPS on IL6 expression observed in the ChP was also demonstrated in PVAT [ 46 ], in which leptin did not induce IL6 mRNA expression also in a physiological state. In turn, in the aorta and AP leptin increased IL6 mRNA expression in both physiological and LPS-challenged conditions [ 45 , 47 ]. One might consider the possibility that a very strong LPS-induction of IL6 expression, observed in the ovine ChP, masked the potential impact of leptin.…”

Section: Discussionmentioning

confidence: 99%

Photoperiod Affects Leptin Action on the Choroid Plexus in Ewes Challenged with Lipopolysaccharide—Study on the mRNA Level

Szczepkowska

Kowalewska

Krawczyńska

et al. 2020

IJMS

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The ovine choroid plexus (ChP) expresses the long isoform of the leptin receptor, which makes this structure a potential target for leptin action. In sheep, leptin concentration in plasma is higher during long days (LD) than short days (SD). This study evaluates the influence a of photoperiod on leptin impact on the gene expression of Toll-like receptor 4 (TLR4), proinflammatory cytokines (IL1B, IL6), their receptors (IL1R1, IL1R2, ILRN, IL6R, IL6ST) and inflammasome components necessary for pro-IL-1β activation (NLRP3, PYCARD, CASP1), chemokine (CCL2), leptin receptor isoforms (LEPRa, LEPRb) and a suppressor of cytokine signalling (SOCS3) in the ChP of ewes treated or not with lipopolysaccharide (LPS). Studies were conducted on adult female sheep divided into four groups (n = 6 in each): control, leptin (20 μg/kg), LPS (400 ng/kg), and LPS and leptin injected under SD and LD photoperiods. The leptin alone did not affect the gene expression but in co-treatment with LPS increased (p < 0.05) IL1B but only during SD, and SOCS3, IL1R2, IL1RN, IL6ST and CCL2 only during LD, and decreased (p < 0.05) the IL1R1 expression only during SD photoperiod. This indicates that the immunomodulatory action of leptin on the ChP is manifested only under the LPS challenge and is photoperiodically dependent.

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The Impact of Photoperiod on the Leptin Sensitivity and Course of Inflammation in the Anterior Pituitary

Cited by 7 publications

References 109 publications

Effect of Acute and Prolonged Inflammation on the Gene Expression of Proinflammatory Cytokines and Their Receptors in the Anterior Pituitary Gland of Ewes

Effect of Acute and Prolonged Inflammation on the Gene Expression of Proinflammatory Cytokines and Their Receptors in the Anterior Pituitary Gland of Ewes

Photoperiod alters the choroid plexus response to LPS-induced acute inflammation in EWES

Photoperiod Affects Leptin Action on the Choroid Plexus in Ewes Challenged with Lipopolysaccharide—Study on the mRNA Level

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