Neurobiology of Sleep and Circadian Rhythms
Berezin, C;Bergum, N;Luchini, K;Curdts, S;Korkis, C;Vigh, J;
| DOI: 10.1016/j.nbscr.2022.100078
Circadian sleep/wake rhythms are synchronized to environmental light/dark cycles in a process known as photoentrainment. We have previously shown that activation of β-endorphin-preferring μ-opioid receptors (MORs) inhibits the light-evoked firing of intrinsically photosensitive retinal ganglion cells (ipRGCs), the sole conduits of photoentrainment. Although we have shown that β-endorphin is expressed in the adult mouse retina, the conditions under which β-endorphin is expressed are unknown. Moreover, it is unclear whether endogenous activation of the MORs expressed by ipRGCs modulates the photoentrainment of sleep/wake cycles. To elucidate this, we first measured the mRNA expression of β-endorphin's precursor, proopiomelanocortin (POMC), at various times of day by quantitative reverse-transcription PCR. POMC mRNA appears to have cyclic expression in the mouse retina. We then studied β-endorphin expression with immunohistochemistry and found that retinal β-endorphin is more highly expressed in the dark/at night. Finally, we used telemetry to measure activity, EEG and EMG in freely moving animals to compare sleep/wake cycles in wild-type and transgenic mice in which only ipRGCs lack functional MORs. Results from these experiments suggest that the MORs expressed by ipRGCs contribute to the induction and maintenance of activity in the dark phase in nocturnal mice, via the promotion of wakefulness and inhibition of slow-wave sleep. Together, these data suggest that endogenous β-endorphin activates MORs expressed by ipRGCs to modulate sleep/wake activity via the photoentrainment pathway.
Coinfection of porcine deltacoronavirus and porcine epidemic diarrhea virus altered viral tropism in gastrointestinal tract in a piglet model
Jiao, Z;Liang, J;Yang, Y;Li, Y;Yan, Z;Hu, G;Gu, C;Hu, X;Cheng, G;Peng, G;Zhang, W;
PMID: 33756424 | DOI: 10.1016/j.virol.2021.03.006
Coinfection of porcine epidemic diarrhea virus (PEDV) and porcine deltacoronavirus (PDCoV) is one of common findings in diarrheal piglets that cause massive economic losses to the pig industry globally. However, the mechanism of the co-infection is unclear. In this study, neonatal non-colostrum-fed piglets were exposed orally with a single infection of PDCoV or PEDV, or coinfection of PDCoV and PEDV. Clinically all viral infected piglets developed watery diarrhea and dehydration in 24 h post-exposure (hpe) and were succumbed to viral diarrhea disease and euthanized at 72 hpe. Histopathologically, acute gastroenteritis is evident in all viral infected piglet. Immunohistochemistry, RNAscope and RT-qPCR demonstrated that PEDV tropism changes from epithelial cells of small intestine to gastric epithelial cells and macrophages in Peyer's patches in the ileum. These findings suggest that coinfection of PDCoV and PEDV can alter PEDV tropism that may affect the outcome of viral disease in piglets. This animal model can be used for the pathogenesis and vaccination of viral coinfection in piglet in the future.
Falcão AM, van Bruggen D, Marques S, Meijer M, Jäkel S, Agirre E, Samudyata, Floriddia EM, Vanichkina DP, Ffrench-Constant C, Williams A, Guerreiro-Cacais AO, Castelo-Branco G.
PMID: 30420755 | DOI: 10.1038/s41591-018-0236-y
Multiple sclerosis (MS) is characterized by an immune system attack targeting myelin, which is produced by oligodendrocytes (OLs). We performed single-cell transcriptomic analysis of OL lineage cells from the spinal cord of mice induced with experimental autoimmune encephalomyelitis (EAE), which mimics several aspects of MS. We found unique OLs and OL precursor cells (OPCs) in EAE and uncovered several genes specifically alternatively spliced in these cells. Surprisingly, EAE-specific OL lineage populations expressed genes involved in antigen processing and presentation via major histocompatibility complex class I and II (MHC-I and -II), and in immunoprotection, suggesting alternative functions of these cells in a disease context. Importantly, we found that disease-specific oligodendroglia are also present in human MS brains and that a substantial number of genes known to be susceptibility genes for MS, so far mainly associated with immune cells, are expressed in the OL lineage cells. Finally, we demonstrate that OPCs can phagocytose and that MHC-II-expressing OPCs can activate memory and effector CD4-positive T cells. Our results suggest that OLs and OPCs are not passive targets but instead active immunomodulators in MS. The disease-specific OL lineage cells, for which we identify several biomarkers, may represent novel direct targets for immunomodulatory therapeutic approaches in MS.
Dilz, J;Auge, I;Groeneveld, K;Reuter, S;Mrowka, R;
PMID: 37061575 | DOI: 10.1038/s41598-023-33110-5
Kidneys are complex organs, and reproducing their function and physiology in a laboratory setting remains difficult. During drug development, potential compounds may exhibit unexpected nephrotoxic effects, which imposes a significant financial burden on pharmaceutical companies. As a result, there is an ongoing need for more accurate model systems. The use of renal organoids to simulate responses to nephrotoxic insults has the potential to bridge the gap between preclinical drug efficacy studies in cell cultures and animal models, and the stages of clinical trials in humans. Here we established an accessible fluorescent whole-mount approach for nuclear and membrane staining to first provide an overview of the organoid histology. Furthermore, we investigated the potential of renal organoids to model responses to drug toxicity. For this purpose, organoids were treated with the chemotherapeutic agent doxorubicin for 48 h. When cell viability was assessed biochemically, the organoids demonstrated a significant, dose-dependent decline in response to the treatment. Confocal microscopy revealed visible tubular disintegration and a loss of cellular boundaries at high drug concentrations. This observation was further reinforced by a dose-dependent decrease of the nuclear area in the analyzed images. In contrast to other approaches, in this study, we provide a straightforward experimental framework for drug toxicity assessment in renal organoids that may be used in early research stages to assist screen for potential adverse effects of compounds.
Xu, T;Zhu, HX;You, X;Ma, JF;Li, X;Luo, PY;Li, Y;Lian, ZX;Gao, CY;
PMID: 36881472 | DOI: 10.1172/jci.insight.167490
Primary Sjogren's syndrome (pSS) is a systemic autoimmune inflammatory disease mainly defined by T cell-dominated destruction of exocrine glands. Currently, CD8+T cells were closely related to the pathogenesis of pSS. However, the single-cell immune profiling of pSS and molecular signatures of pathogenic CD8+T cells have not been well elucidated. Our multiomics investigation identified that both T cell and B cell, especially CD8+T cells, were undergoing significant clonal expansion in pSS patients. TCR clonality analysis revealed that peripheral granzyme (GZM) K+CXCR6+CD8+T cells had higher proportion of shared clones with CD69+CD103-CD8+ tissue resident memory T (TRM) cells in labial glands in pSS. CD69+CD103-CD8+TRM cells featured by high expression of GZMK were more active and cytotoxic in pSS compared with their CD103+ counterparts. Peripheral GZMK+CXCR6+CD8+T cells with higher CD122 expression were increased and harbored a gene signature similar to TRM cells in pSS. Consistently, IL-15 was significantly elevated in pSS plasma and showed the capacity to promote differentiation of CD8+T cells into GZMK+CXCR6+CD8+T cells in a STAT5 dependent manner. Taken together, we depicted the immune landscape of pSS and further conducted comprehensive bioinformatics analysis and in vitro experimental investigation to characterize the pathogenic role and differentiation trajectory of CD8+TRM cells in pSS.
bioRxiv : the preprint server for biology
Lei, HC;Parker, KE;Yuede, CM;McCall, JG;Imai, SI;
PMID: 36711943 | DOI: 10.1101/2023.01.19.524624
Age-associated reduced motivation is a hallmark of neuropsychiatric disorders in the elderly. In our rapidly aging societies, it is critical to keep motivation levels high enough to promote healthspan and lifespan. However, how motivation is reduced during aging remains unknown. Here, we used multiple mouse models to evaluate motivation and related affective states in young and old mice. We also compared the effect of social isolation, a common stressor, to those of aging. We found that both social isolation and aging decreased motivation in mice, but that Bdnf expression in the ventral tegmental area (VTA) was selectively decreased during aging. Furthermore, VTA-specific Bdnf knockdown in young mice recapitulated reduced motivation observed in old mice. These results demonstrate that maintaining Bdnf expression in the VTA could promote motivation to engage in effortful activities and potentially prevent age-associated neuropsychiatric disorders.
Yang, Y;Ahn, J;Edwards, NJ;Benicky, J;Rozeboom, AM;Davidson, B;Karamboulas, C;Nixon, KCJ;Ailles, L;Goldman, R;
PMID: 36428645 | DOI: 10.3390/cancers14225553
Pan-cancer analysis of TCGA and CPTAC (proteomics) data shows that SULF1 and SULF2 are oncogenic in a number of human malignancies and associated with poor survival outcomes. Our studies document a consistent upregulation of SULF1 and SULF2 in HNSC which is associated with poor survival outcomes. These heparan sulfate editing enzymes were considered largely functional redundant but single-cell RNAseq (scRNAseq) shows that SULF1 is secreted by cancer-associated fibroblasts in contrast to the SULF2 derived from tumor cells. Our RNAScope and patient-derived xenograft (PDX) analysis of the HNSC tissues fully confirm the stromal source of SULF1 and explain the uniform impact of this enzyme on the biology of multiple malignancies. In summary, SULF2 expression increases in multiple malignancies but less consistently than SULF1, which uniformly increases in the tumor tissues and negatively impacts survival in several types of cancer even though its expression in cancer cells is low. This paradigm is common to multiple malignancies and suggests a potential for diagnostic and therapeutic targeting of the heparan sulfatases in cancer diseases.
Kaya, T;Mattugini, N;Liu, L;Ji, H;Cantuti-Castelvetri, L;Wu, J;Schifferer, M;Groh, J;Martini, R;Besson-Girard, S;Kaji, S;Liesz, A;Gokce, O;Simons, M;
PMID: 36280798 | DOI: 10.1038/s41593-022-01183-6
A hallmark of nervous system aging is a decline of white matter volume and function, but the underlying mechanisms leading to white matter pathology are unknown. In the present study, we found age-related alterations of oligodendrocyte cell state with a reduction in total oligodendrocyte density in aging murine white matter. Using single-cell RNA-sequencing, we identified interferon (IFN)-responsive oligodendrocytes, which localize in proximity to CD8+ T cells in aging white matter. Absence of functional lymphocytes decreased the number of IFN-responsive oligodendrocytes and rescued oligodendrocyte loss, whereas T-cell checkpoint inhibition worsened the aging response. In addition, we identified a subpopulation of lymphocyte-dependent, IFN-responsive microglia in the vicinity of the CD8+ T cells in aging white matter. In summary, we provide evidence that CD8+ T-cell-induced, IFN-responsive oligodendrocytes and microglia are important modifiers of white matter aging.
Aguilar, K;Comes, G;Canal, C;Quintana, A;Sanz, E;Hidalgo, J;
PMID: 35770802 | DOI: 10.1002/glia.24234
Leigh syndrome is a mitochondrial disease characterized by neurodegeneration, neuroinflammation, and early death. Mice lacking NDUFS4, a mitochondrial complex I subunit (Ndufs4 KO mice), have been established as a good animal model for studying human pathology associated with Leigh syndrome. As the disease progresses, there is an increase in neurodegeneration and neuroinflammation, thereby leading to deteriorating neurological symptoms, including motor deficits, breathing alterations, and eventually, death of the animal. However, despite the magnitude of neuroinflammation associated with brain lesions, the role of neuroinflammatory pathways and their main cellular components have not been addressed directly as relevant players in the disease pathology. Here, we investigate the role of microglial cells, the main immune cells of the CNS, in Leigh-like syndrome pathology, by pharmacologically depleting them using the colony-stimulating factor 1 receptor antagonist PLX3397. Microglial depletion extended lifespan and delayed motor symptoms in Ndufs4 KO mice, likely by preventing neuronal loss. Next, we investigated the role of the major cytokine interleukin-6 (IL-6) in the disease progression. IL-6 deficiency partially rescued breathing abnormalities and modulated gliosis but did not extend the lifespan or rescue motor decline in Ndufs4 KO mice. The present results show that microglial accumulation is pathogenic, in a process independent of IL-6, and hints toward a contributing role of neuroinflammation in the disease of Ndufs4 KO mice and potentially in patients with Leigh syndrome.
Li, J;Ryabinin, A;
| DOI: 10.2139/ssrn.4033172
The centrally-projecting Edinger-Westphal nucleus (EWcp) has been shown to contribute to regulation of multiple functions, including responses to stress and fear, attention, food consumption, addiction, body temperature and maternal behaviors. However, receptors involved in regulation of these behaviors through EWcp remain poorly characterized. On the other hand, the oxytocin peptide (OXT) is also known to regulate a substantial number of physiological responses and behaviors. Here we show that OXT receptors (OXTR) are expressed in EWcp of male and female C57BL/6J mice. These receptors are present on urocortin 1 (UCN)-containing neurons of EWcp and, to a lesser extent, on neurons expressing the vesicular glutamate transporter 2 (vGlut2) of EWcp. Using RNAscope in situ hybridization, we show that UCN and vGlut2 are two intermingled but independent subpopulations of EWcp and characterize their relationship with other populations of neurons in the EWcp. Using immunohistochemistry, we show that intraperitoneal (IP) administration of OXT can induce c-Fos in OXTR-containing neurons of EWcp, suggesting that these receptors on EWcp neurons are functional. A follow up study showed that injection of a dose of OXT (7.7 mg/kg, IP) capable of inducing c-Fos in EWcp also results in temporary hypothermia in mice, while a lower dose (2.3 mg/kg, IP) results in a weaker hypothermia. These studies for the first time describe the EWcp as a site of functionally-significant expression of OXTR. The contribution of these receptors to regulation of various functions of EWcp and OXT needs to be deciphered.
Jin, XT;Drenan, RM;
PMID: 35167902 | DOI: 10.1016/j.neuropharm.2022.108987
The interpeduncular nucleus (IPN) plays a key role in nicotine dependence and is involved in regulation of fear responses, affective states, and novelty processing. IPN neurons express nicotinic acetylcholine receptors (nAChR) and receive strong cholinergic innervation from the ventral medial habenula. Dorsal medial habenula neurons are primarily peptidergic, releasing substance P (SP) mainly onto IPN neurons in the lateral subnucleus (IPL). IPL neurons are sensitive to SP, but it is not known if they are involved in cholinergic transmission like other IPN neurons. We examined nAChR subunit gene expression in IPL neurons, revealing that Chrna7 (α7 nAChR subunit) is expressed in a subset of GABAergic IPL neurons. In patch-clamp recordings from IPL neurons, ACh-evoked inward currents were attenuated by methyllycaconitine (α7 nAChR antagonist) and potentiated by NS1738 (α7 Type I positive allosteric modulator). We confirmed α7 functional expression in IPL neurons by also showing that ACh-evoked currents were potentiated by PNU-120596 (Type II positive allosteric modulator). Additional pharmacological experiments show that IPN neurons expressing α7 nAChRs also express α3β4 nAChRs. Finally, we used 2-photon laser scanning microscopy and nicotine uncaging to directly examine the morphology of IPL neurons that express α7 nAChRs. These results highlight a novel aspect of α7 nAChR neurobiology, adding to the complexity of cholinergic modulation by nAChRs in the IPN.
Porniece Kumar, M;Cremer, AL;Klemm, P;Steuernagel, L;Sundaram, S;Jais, A;Hausen, AC;Tao, J;Secher, A;Pedersen, TÅ;Schwaninger, M;Wunderlich, FT;Lowell, BB;Backes, H;Brüning, JC;
PMID: 34931084 | DOI: 10.1038/s42255-021-00499-0
Insulin acts on neurons and glial cells to regulate systemic glucose metabolism and feeding. However, the mechanisms of insulin access in discrete brain regions are incompletely defined. Here we show that insulin receptors in tanycytes, but not in brain endothelial cells, are required to regulate insulin access to the hypothalamic arcuate nucleus. Mice lacking insulin receptors in tanycytes (IR∆Tan mice) exhibit systemic insulin resistance, while displaying normal food intake and energy expenditure. Tanycytic insulin receptors are also necessary for the orexigenic effects of ghrelin, but not for the anorexic effects of leptin. IR∆Tan mice exhibit increased agouti-related peptide (AgRP) neuronal activity, while displaying blunted AgRP neuronal adaptations to feeding-related stimuli. Lastly, a highly palatable food decreases tanycytic and arcuate nucleus insulin signalling to levels comparable to those seen in IR∆Tan mice. These changes are rooted in modifications of cellular stress responses and of mitochondrial protein quality control in tanycytes. Conclusively, we reveal a critical role of tanycyte insulin receptors in gating feeding-state-dependent regulation of AgRP neurons and systemic insulin sensitivity, and show that insulin resistance in tanycytes contributes to the pleiotropic manifestations of obesity-associated insulin resistance.
