scholarly journals The β-Secretase Substrate Seizure 6–Like Protein (SEZ6L) Controls Motor Functions in Mice

Author(s):  
Emma Ong-Pålsson ◽  
Jasenka Rudan Njavro ◽  
Yvette Wilson ◽  
Martina Pigoni ◽  
Andree Schmidt ◽  
...  

AbstractThe membrane protein seizure 6–like (SEZ6L) is a neuronal substrate of the Alzheimer’s disease protease BACE1, and little is known about its physiological function in the nervous system. Here, we show that SEZ6L constitutive knockout mice display motor phenotypes in adulthood, including changes in gait and decreased motor coordination. Additionally, SEZ6L knockout mice displayed increased anxiety-like behaviour, although spatial learning and memory in the Morris water maze were normal. Analysis of the gross anatomy and proteome of the adult SEZ6L knockout cerebellum did not reveal any major differences compared to wild type, indicating that lack of SEZ6L in other regions of the nervous system may contribute to the phenotypes observed. In summary, our study establishes physiological functions for SEZ6L in regulating motor coordination and curbing anxiety-related behaviour, indicating that aberrant SEZ6L function in the human nervous system may contribute to movement disorders and neuropsychiatric diseases.

2000 ◽  
Vol 279 (2) ◽  
pp. R515-R521 ◽  
Author(s):  
Yukiko Kurihara ◽  
Hiroki Kurihara ◽  
Hiroyuki Morita ◽  
Wei-Hua Cao ◽  
Guang-Yi Ling ◽  
...  

Endothelin (ET)-1 is a 21-amino acid peptide that induces a variety of biological activities, including vasoconstriction and cell proliferation, and its likely involvement in cardiovascular and other diseases has recently led to broad clinical trials of ET receptor antagonists. ET-1 is widely distributed in the central nervous system (CNS), where it is thought to regulate hormone and neurotransmitter release. Here we show that CNS responses to emotional and physical stressors are differentially affected in heterozygous ET-1-knockout mice, which exhibited diminished aggressive and autonomic responses toward intruders (emotional stressors) but responded to restraint-induced (physical) stress more intensely than wild-type mice. This suggests differing roles of ET-1 in the central pathways mediating responses to different types of stress. Hypothalamic levels of ET-1 and the catecholamine metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) were both increased in wild-type mice subjected to intruder stress, whereas MHPG levels were not significantly affected in ET-1-knockout mice. Furthermore, immunohistochemical analysis showed that ET-1 and tyrosine hydroxylase, an enzyme in the catecholamine synthesis pathway, were colocalized within certain neurons of the hypothalamus and amygdala. Our findings suggest that ET-1 modulates central coordination of stress responses in close association with catecholamine metabolism.


2015 ◽  
Vol 309 (5) ◽  
pp. G400-G409 ◽  
Author(s):  
Maja Johansson ◽  
Ana Agusti ◽  
Marta Llansola ◽  
Carmina Montoliu ◽  
Jessica Strömberg ◽  
...  

Hepatic encephalopathy (HE) is one of the primary complications of liver cirrhosis. Current treatments for HE, mainly directed to reduction of ammonia levels, are not effective enough because they cannot completely eliminate hyperammonemia and inflammation, which induce the neurological alterations. Studies in animal models show that overactivation of GABAA receptors is involved in cognitive and motor impairment in HE and that reducing this activation restores these functions. We have developed a new compound, GR3027, that selectively antagonizes the enhanced activation of GABAA receptors by neurosteroids such as allopregnanolone and 3α,21-dihydroxy-5α-pregnan-20-one (THDOC). This work aimed to assess whether GR3027 improves motor incoordination, spatial learning, and circadian rhythms of activity in rats with HE. GR3027 was administered subcutaneously to two main models of HE: rats with chronic hyperammonemia due to ammonia feeding and rats with portacaval shunts (PCS). Motor coordination was assessed in beam walking and spatial learning and memory in the Morris water maze and the radial maze. Circadian rhythms of ambulatory and vertical activity were also assessed. In both hyperammonemic and PCS rats, GR3027 restores motor coordination, spatial memory in the Morris water maze, and spatial learning in the radial maze. GR3027 also partially restores circadian rhythms of ambulatory and vertical activity in PCS rats. GR3027 is a novel approach to treatment of HE that would normalize neurological functions altered because of enhanced GABAergic tone, affording more complete normalization of cognitive and motor function than current treatments for HE.


2010 ◽  
Vol 31 (5) ◽  
pp. 1283-1292 ◽  
Author(s):  
Liaoliao Li ◽  
Zhiyi Zuo

Excitatory amino-acid transporters (EAATs) transport glutamate into cells under physiologic conditions. Excitatory amino-acid transporter type 3 (EAAT3) is the major neuronal EAAT and also uptakes cysteine, the rate-limiting substrate for synthesis of glutathione. Thus, we hypothesize that EAAT3 contributes to providing brain ischemic tolerance. Male 8-week-old EAAT3 knockout mice on CD-1 mouse gene background and wild-type CD-1 mice were subjected to right middle cerebral artery occlusion for 90 minutes. Their brain infarct volumes, neurologic functions, and brain levels of glutathione, nitrotyrosine, and 4-hydroxy-2-nonenal (HNE) were evaluated. The EAAT3 knockout mice had bigger brain infarct volumes and worse neurologic deficit scores and motor coordination functions than did wild-type mice, no matter whether these neurologic outcome parameters were evaluated at 24 hours or at 4 weeks after brain ischemia. The EAAT3 knockout mice contained higher levels of HNE in the ischemic penumbral cortex and in the nonischemic cerebral cortex than did wild-type mice. Glutathione levels in the ischemic and nonischemic cortices of EAAT3 knockout mice tended to be lower than those of wild-type mice. Our results suggest that EAAT3 is important in limiting ischemic brain injury after focal brain ischemia. This effect may involve attenuating brain oxidative stress.


2006 ◽  
Vol 27 (1) ◽  
pp. 44-53 ◽  
Author(s):  
Jody T. Mack ◽  
Vladimir Beljanski ◽  
Athena M. Soulika ◽  
Danyelle M. Townsend ◽  
Carol B. Brown ◽  
...  

ABSTRACT The ATP-binding cassette transporter 2 (ABCA2) is an endolysosomal protein most highly expressed in the central and peripheral nervous system tissues and macrophages. Previous studies indicated its role in cholesterol/steroid (estramustine, estradiol, and progesterone) trafficking/sequestration, oxidative stress response, and Alzheimer's disease. Developmental studies have shown its expression during macrophage and oligodendrocyte differentiation, processes requiring membrane growth. To determine the in vivo function(s) of this transporter, we generated a knockout mouse from a gene-targeted disruption of the murine ABCA2 gene. Knockout males and females are viable and fertile. However, a non-Mendelian inheritance pattern was shown among male progeny of heterozygous crosses. Compared to wild-type and heterozygous littermates, knockout mice displayed a tremor without ataxia, hyperactivity, and reduced body weight; the latter two phenotypes were more marked in females than in males. This sexual disparity suggests a role for ABCA2 in hormone-dependent neurological and/or developmental pathways. Myelin sheath thickness in the spinal cords of knockout mice was greatly increased compared to that in wild-type mice, while a significant reduction in myelin membrane periodicity (compaction) was observed in both spinal cords and cerebra of knockout mice. Loss of ABCA2 function in vivo resulted in abnormal myelin compaction in spinal cord and cerebrum, an ultrastructural defect that we propose to be the cause of the phenotypic tremor.


2021 ◽  
Vol 10 (10) ◽  
pp. 2149
Author(s):  
Ji Yeon Chung ◽  
Seung Jae Lee ◽  
Hyuck Jin Lee ◽  
Jeong Bin Bong ◽  
Chan-Hyuk Lee ◽  
...  

We evaluated the toxic effects of aconitine on the human nervous system and its associated factors, and the general clinical characteristics of patients who visited the emergency room due to aconitine intoxication between 2008 and 2017. We also analyzed the differences related to aconitine processing and administration methods (oral pill, boiled in water, and alcohol-soaked), and the clinical characteristics of consciousness deterioration and neurological symptoms. Of the 41 patients who visited the hospital due to aconitine intoxication, 23 (56.1%) were female, and most were older. Aconitine was mainly used for pain control (28 patients, 68.3%) and taken as oral pills (19 patients, 46%). The patients showed a single symptom or a combination of symptoms; neurological symptoms were the most common (21 patients). All patients who took aconitine after processing with alcohol showed neurological symptoms and a higher prevalence of consciousness deterioration. Neurological symptoms occurred most frequently in patients with aconitine intoxication. Although aconitine intoxication presents with various symptoms, its prognosis may vary with the processing method and prevalence of consciousness deterioration during the early stages. Therefore, the administration method and accompanying symptoms should be comprehensively investigated in patients who have taken aconitine to facilitate prompt and effective treatment and better prognoses.


2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Feixiang Chen ◽  
Weihuang Liu ◽  
Qiang Zhang ◽  
Ping Wu ◽  
Ao Xiao ◽  
...  

AbstractPeripheral nerve injury is a serious health problem and repairing long nerve deficits remains a clinical challenge nowadays. Nerve guidance conduit (NGC) serves as the most promising alternative therapy strategy to autografts but its repairing efficiency needs improvement. In this study, we investigated whether modulating the immune microenvironment by Interleukin-17F (IL-17F) could promote NGC mediated peripheral nerve repair. Chitosan conduits were used to bridge sciatic nerve defect in IL-17F knockout mice and wild-type mice with autografts as controls. Our data revealed that IL-17F knockout mice had improved functional recovery and axonal regeneration of sciatic nerve bridged by chitosan conduits comparing to the wild-type mice. Notably, IL-17F knockout mice had enhanced anti-inflammatory macrophages in the NGC repairing microenvironment. In vitro data revealed that IL-17F knockout peritoneal and bone marrow derived macrophages had increased anti-inflammatory markers after treatment with the extracts from chitosan conduits, while higher pro-inflammatory markers were detected in the Raw264.7 macrophage cell line, wild-type peritoneal and bone marrow derived macrophages after the same treatment. The biased anti-inflammatory phenotype of macrophages by IL-17F knockout probably contributed to the improved chitosan conduit guided sciatic nerve regeneration. Additionally, IL-17F could enhance pro-inflammatory factors production in Raw264.7 cells and wild-type peritoneal macrophages. Altogether, IL-17F may partially mediate chitosan conduit induced pro-inflammatory polarization of macrophages during nerve repair. These results not only revealed a role of IL-17F in macrophage function, but also provided a unique and promising target, IL-17F, to modulate the microenvironment and enhance the peripheral nerve regeneration.


Author(s):  
Naoki Ishii ◽  
Takujiro Homma ◽  
Jaeyong Lee ◽  
Hikaru Mitsuhashi ◽  
Ken-ichi Yamada ◽  
...  

Abstract Superoxide dismutase 1 suppresses oxidative stress within cells by decreasing the levels of superoxide anions. A dysfunction of the ovary and/or an aberrant production of sex hormones are suspected causes for infertility in superoxide dismutase 1-knockout mice. We report on attempts to rescue the infertility in female knockout mice by providing two antioxidants, ascorbic acid and/or coenzyme Q10, as supplements in the drinking water of the knockout mice after weaning and on an investigation of their reproductive ability. On the first parturition, 80% of the untreated knockout mice produced smaller litter sizes compared with wild-type mice (average 2.8 vs 7.3 pups/mouse), and supplementing with these antioxidants failed to improve these litter sizes. However, in the second parturition of the knockout mice, the parturition rate was increased from 18% to 44–75% as the result of the administration of antioxidants. While plasma levels of progesterone at 7.5 days of pregnancy were essentially the same between the wild-type and knockout mice and were not changed by the supplementation of these antioxidants, sizes of corpus luteum cells, which were smaller in the knockout mouse ovaries after the first parturition, were significantly ameliorated in the knockout mouse with the administration of the antioxidants. Moreover, the impaired vasculogenesis in uterus/placenta was also improved by ascorbic acid supplementation. We thus conclude that ascorbic acid and/or coenzyme Q10 are involved in maintaining ovarian and uterus/placenta homeostasis against insults that are augmented during pregnancy and that their use might have positive effects in terms of improving female fertility.


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