In rodents, the melatonin production by the pineal gland is controlled through adrenergic signaling from the suprachiasmatic nuclei and regulation of the principal enzyme in its synthesis, arylalkylamine-N-acetyltransferase (AANAT). In the present study, we identified increased isoprenaline-induced aa-nat expression and nocturnal AANAT activity in the pineal glands in response to the silencing of the signal transducer and activator of transcription 3 (STAT3) with siRNA or STAT3 inhibitors WP1066 and AZD1480. This AANAT activity enhancement in vivo did not interfere with light-induced AANAT suppression. Systemic or in vitro lipopolysaccharide (LPS) administration markedly increased Stat3 expression and STAT3 phosphorylation, but it did not significantly affect AANAT expression or activity. Simultaneous LPS administration and Stat3 silencing enhanced the aa-nat transcription and AANAT activity to a similar extent as Stat3 inhibition without LPS co-administration. Furthermore, we describe the circadian rhythmicity in Stat3 expression and the phosphorylated form of STAT3 protein in the rat pineal gland. Our data suggest that the higher nocturnal endogenous level of STAT3 in the pineal gland decelerates or hampers the process of NA-induced AANAT activation or affects the AANAT enzyme stability.
- Publikační typ
- časopisecké články MeSH
Social defeat stress affects behavior and changes the expression of the genes underlying neuronal plasticity in the brain. The circadian clock regulates most neuronal processes in the brain, which results in daily variations of complex behavior, and any disturbance in circadian clock oscillations increases the risk of mood and cognitive disbalance. In this study, we assessed the effect of acute and repeated social defeat stress on Per2 and Nr1d1 expression in prefrontal cortexes, hippocampi, pineal glands, olfactory bulbs, cerebella, and pituitary glands. We also evaluated the effect of our experimental setting on levels of Bdnf and plasma corticosterone, two markers widely used to asses the impact of stress on mammalian physiology. Our data show that single and repeated social defeat stress upregulates the expression of both clock genes and Bdnf in all brain structures, and corticosterone in the blood. While the general pattern of Bdnf upregulation suggests higher sensitivity in the intruder group, the clock genes are induced more significantly in residents, especially by repeated stress sessions. Our work thus suggests that the model of stress-induced anxiety and depression should consider a group of residents because, for some parameters, they may respond more distinctively than intruders.LAY SUMMARYThe resident/intruder experimental paradigm affects the expression of clock genes Per2, Nr1d1and Bdnf in the brain structures and plasma corticosterone level. The induction of clock genes is evident in both experimental groups; however, it is more marked in residents. Together with the significant increase in Bdnf levels in the majority of brain structures and plasma corticosterone in residents, our data suggest that in the model of social defeat stress, the utility of an experimental group of residents could be contributive.
- MeSH
- kortikosteron MeSH
- mozek metabolismus MeSH
- mozkový neurotrofický faktor * genetika metabolismus MeSH
- potkani Wistar MeSH
- proteiny CLOCK * genetika metabolismus MeSH
- psychický stres * genetika MeSH
- sociální chování MeSH
- sociální porážka MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The circadian clock regulates bodily rhythms by time cues that result from the integration of genetically encoded endogenous rhythms with external cycles, most potently with the light/dark cycle. Chronic exposure to constant light in adulthood disrupts circadian system function and can induce behavioral and physiological arrhythmicity with potential clinical consequences. Since the developing nervous system is particularly vulnerable to experiences during the critical period, we hypothesized that early-life circadian disruption would negatively impact the development of the circadian clock and its adult function. Newborn rats were subjected to a constant light of 16 lux from the day of birth through until postnatal day 20, and then they were housed in conditions of L12 h (16 lux): D12 h (darkness). The circadian period was measured by locomotor activity rhythm at postnatal day 60, and the rhythmic expressions of clock genes and tissue-specific genes were detected in the suprachiasmatic nuclei, retinas, and pineal glands at postnatal days 30 and 90. Our data show that early postnatal exposure to constant light leads to a prolonged endogenous period of locomotor activity rhythm and affects the rhythmic gene expression in all studied brain structures later in life.
- Publikační typ
- časopisecké články MeSH
Benzodiazepines (BZDs) are widely used in patients of all ages. Unlike adults, neonatal animals treated with BZDs exhibit a variety of behavioral deficits later in life; however, the mechanisms underlying these deficits are poorly understood. This study aims to examine whether administration of clonazepam (CZP; 1 mg/kg/day) in 7-11-day-old rats affects Gama aminobutyric acid (GABA)ergic receptors in both the short and long terms. Using RT-PCR and quantitative autoradiography, we examined the expression of the selected GABAA receptor subunits (α1, α2, α4, γ2, and δ) and the GABAB B2 subunit, and GABAA, benzodiazepine, and GABAB receptor binding 48 h, 1 week, and 2 months after treatment discontinuation. Within one week after CZP cessation, the expression of the α2 subunit was upregulated, whereas that of the δ subunit was downregulated in both the hippocampus and cortex. In the hippocampus, the α4 subunit was downregulated after the 2-month interval. Changes in receptor binding were highly dependent on the receptor type, the interval after treatment cessation, and the brain structure. GABAA receptor binding was increased in almost all of the brain structures after the 48-h interval. BZD-binding was decreased in many brain structures involved in the neuronal networks associated with emotional behavior, anxiety, and cognitive functions after the 2-month interval. Binding of the GABAB receptors changed depending on the interval and brain structure. Overall, the described changes may affect both synaptic development and functioning and may potentially cause behavioral impairment.
- MeSH
- benzodiazepiny farmakologie MeSH
- GABA metabolismus MeSH
- hipokampus účinky léků metabolismus MeSH
- klonazepam farmakologie MeSH
- krysa rodu rattus MeSH
- kvantitativní polymerázová řetězová reakce MeSH
- mozek účinky léků metabolismus MeSH
- novorozená zvířata MeSH
- potkani inbrední WF MeSH
- receptory GABA-A metabolismus MeSH
- receptory GABA-B metabolismus MeSH
- vazba proteinů MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Huntingtonova choroba (Huntington disease; HD) je autozomálně dominantní, dědičné neurodegenerativní onemocnění s fatální prognózou. Kromě typicky progresivně se zhoršujících motorických funkcí lze u pacientů s HD pozorovat i kognitivní a behaviorální poruchy. Mezi nejčastější symptomy patří také poruchy spánku, které mají velmi závažný dopad na kvalitu života jak pacientů, tak jejich blízkých a které bývají asociovány s narušeným cirkadiánním systémem. Stabilizace délky i kvality spánku posílením cirkadiánního systému by mohla zmírnit či potlačit mnohé symptomy HD, jež mají sice přímou příčinu v etiologii HD, sekundárně mohou být ale zesíleny dlouhodobým nedostatečným spánkem či právě poruchami cirkadiánního systému. U premanifestujících pacientů by takové zásahy mohly vést k pomalejšímu rozvoji či nástupu zejména kognitivních symptomů nemoci. Terapie synchronizujícím jasným světlem, která se již osvědčila jako doplňkový nástroj k léčbě afektivních i některých neurodegenerativních nemocí, by mohla vést k radikálnímu zlepšení života pacientů alespoň v počátečních stadiích onemocnění.
Huntington disease (HD) is an autosomal-dominant, hereditary neurodegenerative disease with a fatal prognosis. Besides the typical progressive deterioration of motor functions, cognitive and behavioral disorders can also be observed in patients with HD. The most common symptoms also include sleep disorders that seriously affect the quality of life of the patients but also of their relatives and which are being associated with a disrupted circadian system. Stabilization of sleep lenght and quality by strengthening the circadian system could mitigate or suppress many HD symptoms, which, although being a direct result of the disease etiology, can secondarily be heightened by long-term insufficient sleep or circadian system disturbances. Such interventions could lead to slower especially cognitive symptom progression or onset in pre-manifesting patients. Synchronizing bright light therapy, which has already proven useful as a complementary tool for the treatment of affective disorders, as well as some neurodegenerative diseases, could lead to radical improvement of the patients‘ quality of life, at least in the early stages of disease development.
- Klíčová slova
- hodinové geny,
- MeSH
- cirkadiánní hodiny MeSH
- fototerapie metody MeSH
- Huntingtonova nemoc * komplikace terapie MeSH
- lidé MeSH
- poruchy spánku a bdění terapie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
The CB1 cannabinoid receptors have been found in the rodent suprachiasmatic nucleus, and their activation suppresses the light-induced phase shift in locomotor rhythmicity of mice and hamsters. Here, we show that the CB1 receptor agonist CP55940 significantly attenuates the light-induced phase delay in rats as well. Furthermore, it blocks the light induction of c-Fos and light-induced downregulation of pERK1/2 in the SCN, and the CB1 antagonist AM251 prevents the photic induction of pERK1/2 and reduces pGSK3β after photic stimulation. Our data suggest that the modulation of the cannabinoid receptor activity may affect the photic entrainment via the setting of the SCN sensitivity to light.
- MeSH
- agonisté kanabinoidních receptorů farmakologie MeSH
- antagonisté kanabinoidních receptorů farmakologie MeSH
- cyklohexanoly farmakologie MeSH
- nucleus suprachiasmaticus účinky léků fyziologie účinky záření MeSH
- piperidiny farmakologie MeSH
- pohybová aktivita účinky léků účinky záření MeSH
- potkani Wistar MeSH
- pyrazoly farmakologie MeSH
- světlo MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
γ-aminobutyric acid (GABA) pathways play an important role in neuronal circuitry formation during early postnatal development. Our previous studies revealed an increased risk for adverse neurodevelopmental consequences in animals exposed to benzodiazepines, which enhance GABA inhibition via GABAA receptors. We reported that administration of the benzodiazepine clonazepam (CZP) during postnatal days 7-11 resulted in permanent behavioral alterations. However, the mechanisms underlying these changes are unknown. We hypothesized that early CZP exposure modifies development of glutamatergic receptors and their composition due to the tight developmental link between GABAergic functions and maturation of glutamatergic signaling. These changes may alter excitatory synapses, as well as neuronal connectivity and function of the neural network. We used quantitative real-time PCR and quantitative autoradiography to examine changes in NMDA and AMPA receptor composition and binding in response to CZP (1 mg/kg/day) administration for five consecutive days, beginning on P7. Brains were collected 48 h, 1 week, or 60 days after treatment cessation, and mRNA subunit expression was assessed in the hippocampus and sensorimotor cortex. A separate group of animals was used to determine binding to NMDA in different brain regions. Patterns of CZP-induced alterations in subunit mRNA expression were dependent on brain structure, interval after CZP cessation, and receptor subunit type. In the hippocampus, upregulation of GluN1, GluN3, and GluR2 subunit mRNA was observed at the 48-h interval, and GluN2A and GluR1 mRNA expression levels were higher 1 week after CZP cessation compared to controls, while GluN2B was downregulated. CZP exposure increased GluN3 and GluR2 subunit mRNA expression levels in the sensorimotor cortex 48 h after treatment cessation. GluA3 was higher 1 week after the CZP exposure, and GluN2A and GluA4 mRNA were significantly upregulated 2 months later. Expression of other subunits was not significantly different from that of the controls. NMDA receptor binding increased 1 week after the end of exposure in most hippocampal and cortical areas, including the sensorimotor cortex at the 48-h interval. CZP exposure decreased NMDA receptor binding in most evaluated hippocampal and cortical areas 2 months after the end of administration. Overall, early CZP exposure likely results in long-term glutamatergic receptor modulation that may affect synaptic development and function, potentially causing behavioral impairment.
- Publikační typ
- časopisecké články MeSH
The circadian clock in the suprachiasmatic nucleus (SCN) regulates daily rhythms in physiology and behaviour and is an important part of the mammalian homeostatic system. Previously, we have shown that systemic inflammatory stimulation with lipopolysaccharide (LPS) induced the daytime-dependent phosphorylation of STAT3 in the SCN. Here, we demonstrate the LPS-induced Stat3 mRNA expression in the SCN and show also the circadian rhythm in Stat3 expression in the SCN, with high levels during the day. Moreover, we examined the effects of LPS (1mg/kg), applied either during the day or the night, on the rhythm in locomotor activity of male Wistar rats. We observed that recovery of normal locomotor activity patterns took longer when the animals were injected during the night. The clock genes Per1, Per2 and Nr1d1, and phosphorylation of kinases ERK1/2 and GSK3β are sensitive to external cues and function as the molecular entry for external signals into the circadian clockwork. We also studied the immediate changes in these clock genes expressions and the phosphorylation of ERK1/2 and GSK3β in the suprachiasmatic nucleus in response to daytime or night-time inflammatory stimulation. We revealed mild and transient changes with respect to the controls. Our data stress the role of STAT3 in the circadian clock response to the LPS and provide further evidence of the interaction between the circadian clock and immune system.
- MeSH
- cirkadiánní rytmus účinky léků MeSH
- krysa rodu rattus MeSH
- lipopolysacharidy toxicita MeSH
- lokomoce účinky léků MeSH
- MAP kinasový signální systém účinky léků MeSH
- mitogenem aktivovaná proteinkinasa 3 metabolismus MeSH
- nucleus suprachiasmaticus metabolismus patologie MeSH
- potkani Wistar MeSH
- regulace genové exprese účinky léků MeSH
- transkripční faktor STAT3 biosyntéza MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Signal transducers and activators of transcription (STAT) proteins regulate many aspects of cellular physiology from growth and differentiations to immune responses. Using immunohistochemistry, we show the daily rhythm of STAT3 protein in the rat suprachiasmatic nucleus (SCN), with low but significant amplitude peaking in the morning. We also reveal the strong expression of STAT5A in astrocytes of the SCN and the STAT5B signal in nonastrocytic cells. Administration of lipopolysaccharide (LPS) acutely induced phosphorylation of STAT3 on Tyr705 during both the day and the night and induced phosphorylation on Ser727 but only after the daytime application. The LPS-induced phospho-STAT3 (Tyr705) remained elevated for 24 hr after the daytime application but declined within 8 hr when LPS was applied at night.
- MeSH
- analýza rozptylu MeSH
- časové faktory MeSH
- cirkadiánní rytmus účinky léků MeSH
- fosforylace účinky léků MeSH
- gliový fibrilární kyselý protein metabolismus MeSH
- krysa rodu rattus MeSH
- lipopolysacharidy farmakologie MeSH
- nucleus suprachiasmaticus cytologie účinky léků MeSH
- potkani Wistar MeSH
- regulace genové exprese účinky léků MeSH
- transkripční faktor STAT3 metabolismus MeSH
- transkripční faktor STAT5 metabolismus MeSH
- tyrosin-3-monooxygenasa metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Radiation and genotoxic drugs are two of the cornerstones of current cancer treatment strategy. However, this type of therapy often suffers from radio- or chemo-resistance caused by DNA repair mechanisms. With the aim of increasing the efficacy of these treatments, there has been great interest in studying DNA damage responses (DDR). Among the plethora of signal and effector proteins involved in DDR, three related kinases ATM (ataxia telangiectasia mutated), ATR (ATM and Rad3-related) and DNA-PK (DNA-dependent protein kinase) play the main roles in initiation and regulation of signaling pathways in response to DNA double and single strand breaks (DSB and SSB). ATM inhibitors, as well as those of ATR and DNA-PK, provide an opportunity to sensitize cancer cells to therapy. Moreover, they can lead to selective killing of cancer cells, exploiting a concept known as synthetic lethality. However, only a very few selective inhibitors have been identified to this date. This mini-review is focused both on the development of selective inhibitors of ATM and other inhibitors which have ATM as one of their targets.
- MeSH
- ATM protein antagonisté a inhibitory metabolismus MeSH
- inhibitory proteinkinas chemie farmakologie MeSH
- lidé MeSH
- nádory farmakoterapie enzymologie genetika MeSH
- objevování léků * MeSH
- oprava DNA účinky léků MeSH
- poškození DNA účinky léků MeSH
- signální transdukce účinky léků MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
