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Schlaeger L, Olejniczak I, Lehmann M, Schmidt CX, Astiz M, Oster H, Pilorz V. Estrogen-mediated coupling via gap junctions in the suprachiasmatic nucleus. Eur J Neurosci 2024; 59:1723-1742. [PMID: 38326974 DOI: 10.1111/ejn.16270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 01/11/2024] [Accepted: 01/22/2024] [Indexed: 02/09/2024]
Abstract
The circadian clock orchestrates many physiological and behavioural rhythms in mammals with 24-h periodicity, through a hierarchical organisation, with the central clock located in the suprachiasmatic nucleus (SCN) in the hypothalamus. The circuits of the SCN generate circadian rhythms with precision, relying on intrinsic coupling mechanisms, for example, neurotransmitters like arginine vasopressin (AVP), vasoactive intestinal peptide (VIP), neuronal gamma-aminobutyric acid (GABA) signalling and astrocytes connected by gap junctions composed of connexins (Cx). In female rodents, the presence of estrogen receptors (ERs) in the dorsal SCN suggests an influence of estrogen (E2) on the circuit timekeeping that could regulate circadian rhythm and coupling. To investigate this, we used SCN explants together with hypothalamic neurons and astrocytes. First, we showed that E2 stabilised the circadian amplitude in the SCN when rAVPs (receptor-associated vasopressin peptides) were inhibited. However, the phase delay induced by VIPAC2 (VIP receptors) inhibition remained unaffected by E2. We then showed that E2 exerted its effects in the SCN via ERβ (estrogen receptor beta), resulting in increased expression of Cx36 and Cx43. Notably, specific inhibition of both connexins resulted in a significant reduction in circadian amplitude within the SCN. Remarkably, E2 restored the period with inhibited Cx36 but not with Cx43 inhibition. This implies that the network between astrocytes and neurons, responsible for coupling in the SCN, can be reinforced through E2. In conclusion, these findings provide new insights into how E2 regulates circadian rhythms ex vivo in an ERβ-dependent manner, underscoring its crucial role in fortifying the SCN's rhythm.
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Affiliation(s)
- Lina Schlaeger
- Institute of Neurobiology, Center of Brain, Behaviour and Metabolism, Marie-Curie-Strasse, University of Lübeck, Lübeck, Germany
| | - Iwona Olejniczak
- Institute of Neurobiology, Center of Brain, Behaviour and Metabolism, Marie-Curie-Strasse, University of Lübeck, Lübeck, Germany
| | - Marianne Lehmann
- Institute of Neurobiology, Center of Brain, Behaviour and Metabolism, Marie-Curie-Strasse, University of Lübeck, Lübeck, Germany
| | - Cosima Xenia Schmidt
- Institute of Neurobiology, Center of Brain, Behaviour and Metabolism, Marie-Curie-Strasse, University of Lübeck, Lübeck, Germany
| | - Mariana Astiz
- Institute of Neurobiology, Center of Brain, Behaviour and Metabolism, Marie-Curie-Strasse, University of Lübeck, Lübeck, Germany
- Achucarro Basque Center for Neuroscience, Leioa, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Henrik Oster
- Institute of Neurobiology, Center of Brain, Behaviour and Metabolism, Marie-Curie-Strasse, University of Lübeck, Lübeck, Germany
| | - Violetta Pilorz
- Institute of Neurobiology, Center of Brain, Behaviour and Metabolism, Marie-Curie-Strasse, University of Lübeck, Lübeck, Germany
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Bahiru MS, Bittman EL. Adult Neurogenesis Is Altered by Circadian Phase Shifts and the Duper Mutation in Female Syrian Hamsters. eNeuro 2023; 10:ENEURO.0359-22.2023. [PMID: 36878716 PMCID: PMC10062491 DOI: 10.1523/eneuro.0359-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 02/10/2023] [Accepted: 02/16/2023] [Indexed: 03/08/2023] Open
Abstract
Cell birth and survival in the adult hippocampus are regulated by a circadian clock. Rotating shift work and jet lag disrupt circadian rhythms and aggravate disease. Internal misalignment, a state in which abnormal phase relationships prevail between and within organs, is proposed to account for adverse effects of circadian disruption. This hypothesis has been difficult to test because phase shifts of the entraining cycle inevitably lead to transient desynchrony. Thus, it remains possible that phase shifts, regardless of internal desynchrony, account for adverse effects of circadian disruption and alter neurogenesis and cell fate. To address this question, we examined cell birth and differentiation in the duper Syrian hamster (Mesocricetus auratus), a Cry1-null mutant in which re-entrainment of locomotor rhythms is greatly accelerated. Adult females were subjected to alternating 8 h advances and delays at eight 16 d intervals. BrdU, a cell birth marker, was given midway through the experiment. Repeated phase shifts decreased the number of newborn non-neuronal cells in WT, but not in duper hamsters. The duper mutation increased the number of BrdU-IR cells that stained for NeuN, which marks neuronal differentiation. Immunocytochemical staining for proliferating cell nuclear antigen indicated no overall effect of genotype or repeated shifts on cell division rates after 131 days. Cell differentiation, assessed by doublecortin, was higher in duper hamsters but was not significantly altered by repeated phase shifts. Our results support the internal misalignment hypothesis and indicate that Cry1 regulates cell differentiation. Phase shifts may determine neuronal stem cell survival and time course of differentiation after cell birth. Figure created with BioRender.
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Affiliation(s)
- Michael Seifu Bahiru
- Program in Neuroscience and Behavior, University of Massachusetts, Amherst, Massachusetts 01003
| | - Eric L Bittman
- Program in Neuroscience and Behavior, University of Massachusetts, Amherst, Massachusetts 01003
- Department of Biology, University of Massachusetts, Amherst, Massachusetts 01003
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Srimani S, Schmidt CX, Gómez-Serranillos MP, Oster H, Divakar PK. Modulation of Cellular Circadian Rhythms by Secondary Metabolites of Lichens. Front Cell Neurosci 2022; 16:907308. [PMID: 35813500 PMCID: PMC9260025 DOI: 10.3389/fncel.2022.907308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 05/20/2022] [Indexed: 12/14/2022] Open
Abstract
Background Most mammalian cells harbor molecular circadian clocks that synchronize physiological functions with the 24-h day-night cycle. Disruption of circadian rhythms, through genetic or environmental changes, promotes the development of disorders like obesity, cardiovascular diseases, and cancer. At the cellular level, circadian, mitotic, and redox cycles are functionally coupled. Evernic (EA) and usnic acid (UA), two lichen secondary metabolites, show various pharmacological activities including anti-oxidative, anti-inflammatory, and neuroprotective action. All these effects have likewise been associated with a functional circadian clock. Hypothesis/Purpose To test, if the lichen compounds EA and UA modulate circadian clock function at the cellular level. Methods We used three different cell lines and two circadian luminescence reporter systems for evaluating dose- and time-dependent effects of EA/UA treatment on cellular clock regulation at high temporal resolution. Output parameters studied were circadian luminescence rhythm period, amplitude, phase, and dampening rate. Results Both compounds had marked effects on clock rhythm amplitudes and dampening independent of cell type, with UA generally showing a higher efficiency than EA. Only in fibroblast cells, significant effects on clock period were observed for UA treated cells showing shorter and EA treated cells showing longer period lengths. Transient treatment of mouse embryonic fibroblasts at different phases had only minor clock resetting effects for both compounds. Conclusion Secondary metabolites of lichen alter cellular circadian clocks through amplitude reduction and increased rhythm dampening.
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Affiliation(s)
- Soumi Srimani
- Institute of Neurobiology, Center of Brain, Behavior & Metabolism (CBBM), University of Lübeck, Lübeck, Germany
- Department of Pharmacology, Pharmacognosy and Botany, Faculty of Pharmacy, Complutense University of Madrid, Madrid, Spain
| | - Cosima Xenia Schmidt
- Institute of Neurobiology, Center of Brain, Behavior & Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Maria Pilar Gómez-Serranillos
- Department of Pharmacology, Pharmacognosy and Botany, Faculty of Pharmacy, Complutense University of Madrid, Madrid, Spain
| | - Henrik Oster
- Institute of Neurobiology, Center of Brain, Behavior & Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Pradeep K. Divakar
- Department of Pharmacology, Pharmacognosy and Botany, Faculty of Pharmacy, Complutense University of Madrid, Madrid, Spain
- *Correspondence: Pradeep K. Divakar
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Riggle JP, Onishi KG, Love JA, Beach DE, Zucker I, Prendergast BJ. Spontaneous Recovery of Circadian Organization in Mice Lacking a Core Component of the Molecular Clockwork. J Biol Rhythms 2021; 37:94-109. [PMID: 34931572 DOI: 10.1177/07487304211060896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Circadian rhythms are generated by interlocked transcriptional-translational feedback loops of circadian clock genes and their protein products. Mice homozygous for a functional deletion in the Period-2 gene (Per2m/m mice) exhibit short free-running circadian periods and eventually lose behavioral circadian rhythmicity in constant darkness (DD). We investigated Per2m/m mice in DD for several months and identified a categorical sex difference in the dependence on Per2 for maintenance of circadian rhythms. Nearly all female Per2m/m mice became circadian arrhythmic in DD, whereas free-running rhythms persisted in 37% of males. Remarkably, with extended testing, Per2m/m mice did not remain arrhythmic in DD, but after varying intervals spontaneously recovered robust, free-running circadian rhythms, with periods shorter than those expressed prior to arrhythmia. Spontaneous recovery was strikingly sex-biased, occurring in 95% of females and 33% of males. Castration in adulthood resulted in male Per2m/m mice exhibiting female-like levels of arrhythmia in DD, but did not affect spontaneous recovery. The circadian pacemaker of many gonad-intact males, but not females, can persist in DD for long intervals without a functional PER2 protein; their circadian clocks may be in an unstable equilibrium, incapable of sustaining persistent coherent circadian organization, resulting in transient cycles of circadian organization and arrhythmia.
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Affiliation(s)
- Jonathan P Riggle
- Department of Psychology and Institute for Mind and Biology, The University of Chicago, Chicago, Illinois
| | - Kenneth G Onishi
- Department of Psychology and Institute for Mind and Biology, The University of Chicago, Chicago, Illinois
| | - Jharnae A Love
- Department of Psychology and Institute for Mind and Biology, The University of Chicago, Chicago, Illinois
| | - Dana E Beach
- Department of Psychology and Institute for Mind and Biology, The University of Chicago, Chicago, Illinois
| | - Irving Zucker
- Department of Psychology and Department of Integrative Biology, University of California, Berkeley, Berkeley, California
| | - Brian J Prendergast
- Department of Psychology and Institute for Mind and Biology, The University of Chicago, Chicago, Illinois.,Committee on Neurobiology, The University of Chicago, Chicago, Illinois
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Joye DAM, Evans JA. Sex differences in daily timekeeping and circadian clock circuits. Semin Cell Dev Biol 2021; 126:45-55. [PMID: 33994299 DOI: 10.1016/j.semcdb.2021.04.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 04/24/2021] [Accepted: 04/29/2021] [Indexed: 11/19/2022]
Abstract
The circadian system regulates behavior and physiology in many ways important for health. Circadian rhythms are expressed by nearly every cell in the body, and this large system is coordinated by a central clock in the suprachiasmatic nucleus (SCN). Sex differences in daily rhythms are evident in humans and understanding how circadian function is modulated by biological sex is an important goal. This review highlights work examining effects of sex and gonadal hormones on daily rhythms, with a focus on behavior and SCN circuitry in animal models commonly used in pre-clinical studies. Many questions remain in this area of the field, which would benefit from further work investigating this topic.
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Affiliation(s)
- Deborah A M Joye
- Marquette University, Department of Biomedical Sciences, Milwaukee, WI, USA
| | - Jennifer A Evans
- Marquette University, Department of Biomedical Sciences, Milwaukee, WI, USA.
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