Hypnotic effect of thalidomide is independent of teratogenic ubiquitin/proteasome pathway

Thalidomide exerts its teratogenic and immunomodulatory effects by binding to cereblon (CRBN) and thereby inhibiting/modifying the CRBN-mediated ubiquitination pathway consisting of the Cullin4-DDB1-ROC1 E3 ligase complex. The mechanism of thalidomide’s classical hypnotic effect remains largely unexplored, however. Here we examined whether CRBN is involved in the hypnotic effect of thalidomide by generating mice harboring a thalidomide-resistant mutant allele of Crbn (Crbn YW/AA knock-in mice). Thalidomide increased non-REM sleep time in Crbn YW/AA knock-in homozygotes and heterozygotes to a similar degree as seen in wild-type littermates. Thalidomide similarly depressed excitatory synaptic transmission in the cortical slices obtained from wild-type and Crbn YW/AA homozygous knock-in mice without affecting GABAergic inhibition. Thalidomide induced Fos expression in vasopressin-containing neurons of the supraoptic nucleus and reduced Fos expression in the tuberomammillary nuclei. Thus, thalidomide’s hypnotic effect seems to share some downstream mechanisms with general anesthetics and GABAA-activating sedatives but does not involve the teratogenic CRBN-mediated ubiquitin/proteasome pathway.

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Toll-like Receptor 4 Signaling in Ventilator-induced Diaphragm Atrophy

Anesthesiology ◽

10.1097/aln.0b013e3182608cc0 ◽

2012 ◽

Vol 117 (2) ◽

pp. 329-338 ◽

Cited By ~ 34

Author(s):

Willem-Jan M. Schellekens ◽

Hieronymus W. H. van Hees ◽

Michiel Vaneker ◽

Marianne Linkels ◽

P. N. Richard Dekhuijzen ◽

...

Keyword(s):

Mechanical Ventilation ◽

Caspase 3 ◽

Toll Like Receptor ◽

Wild Type ◽

Toll Like Receptor 4 ◽

Ubiquitin Proteasome Pathway ◽

Ubiquitin Proteasome ◽

Proteasome Pathway ◽

Diaphragm Atrophy ◽

Deficient Mice

Background Mechanical ventilation induces diaphragm muscle atrophy, which plays a key role in difficult weaning from mechanical ventilation. The signaling pathways involved in ventilator-induced diaphragm atrophy are poorly understood. The current study investigated the role of Toll-like receptor 4 signaling in the development of ventilator-induced diaphragm atrophy. Methods Unventilated animals were selected for control: wild-type (n = 6) and Toll-like receptor 4 deficient mice (n = 6). Mechanical ventilation (8 h): wild-type (n = 8) and Toll-like receptor 4 deficient (n = 7) mice.Myosin heavy chain content, proinflammatory cytokines, proteolytic activity of the ubiquitin-proteasome pathway, caspase-3 activity, and autophagy were measured in the diaphragm. Results Mechanical ventilation reduced myosin content by approximately 50% in diaphragms of wild-type mice (P less than 0.05). In contrast, ventilation of Toll-like receptor 4 deficient mice did not significantly affect diaphragm myosin content. Likewise, mechanical ventilation significantly increased interleukin-6 and keratinocyte-derived chemokine in the diaphragm of wild-type mice, but not in ventilated Toll-like receptor 4 deficient mice. Mechanical ventilation increased diaphragmatic muscle atrophy factor box transcription in both wild-type and Toll-like receptor 4 deficient mice. Other components of the ubiquitin-proteasome pathway and caspase-3 activity were not affected by ventilation of either wild-type mice or Toll-like receptor 4 deficient mice. Mechanical ventilation induced autophagy in diaphragms of ventilated wild-type mice, but not Toll-like receptor 4 deficient mice. Conclusion Toll-like receptor 4 signaling plays an important role in the development of ventilator-induced diaphragm atrophy, most likely through increased expression of cytokines and activation of lysosomal autophagy.

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Menin Missense Mutants Associated with Multiple Endocrine Neoplasia Type 1 Are Rapidly Degraded via the Ubiquitin-Proteasome Pathway

Molecular and Cellular Biology ◽

10.1128/mcb.24.15.6569-6580.2004 ◽

2004 ◽

Vol 24 (15) ◽

pp. 6569-6580 ◽

Cited By ~ 63

Author(s):

Hiroko Yaguchi ◽

Naganari Ohkura ◽

Maho Takahashi ◽

Yuko Nagamura ◽

Issay Kitabayashi ◽

...

Keyword(s):

Multiple Endocrine Neoplasia ◽

Multiple Endocrine Neoplasia Type ◽

Suppressor Gene ◽

Missense Mutations ◽

Wild Type ◽

Ubiquitin Proteasome Pathway ◽

Endocrine Neoplasia ◽

Ubiquitin Proteasome ◽

Proteasome Pathway

ABSTRACT MEN1 is a tumor suppressor gene that is responsible for multiple endocrine neoplasia type 1 (MEN1) and that encodes a 610-amino-acid protein, called menin. While the majority of germ line mutations identified in MEN1 patients are frameshift and nonsense mutations resulting in truncation of the menin protein, various missense mutations have been identified whose effects on menin activity are unclear. For this study, we analyzed a series of menin proteins with single amino acid alterations and found that all of the MEN1-causing missense mutations tested led to greatly diminished levels of the affected proteins in comparison with wild-type and benign polymorphic menin protein levels. We demonstrate here that the reduced levels of the mutant proteins are due to rapid degradation via the ubiquitin-proteasome pathway. Furthermore, the mutants, but not wild-type menin, interact both with the molecular chaperone Hsp70 and with the Hsp70-associated ubiquitin ligase CHIP, and the overexpression of CHIP promotes the ubiquitination of the menin mutants in vivo. These findings reveal that MEN1-causing missense mutations lead to a loss of function of menin due to enhanced proteolytic degradation, which may be a common mechanism for inactivating tumor suppressor gene products in familial cancer.

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Faculty Opinions recommendation of Hypnotic effect of thalidomide is independent of teratogenic ubiquitin/proteasome pathway.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.738565457.793578389 ◽

2020 ◽

Author(s):

Philip Burcham

Keyword(s):

Ubiquitin Proteasome Pathway ◽

Hypnotic Effect ◽

Ubiquitin Proteasome ◽

Proteasome Pathway

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Wild-type menin is rapidly degraded via the ubiquitin-proteasome pathway in a rat insulinoma cell line

Bioscience Reports ◽

10.1042/bsr20190471 ◽

2019 ◽

Vol 39 (10) ◽

Author(s):

Zongzhe Jiang ◽

Shengrong Wan ◽

Bowen Xing

Keyword(s):

Cell Line ◽

Germ Line ◽

Wild Type ◽

Ubiquitin Proteasome Pathway ◽

Insulinoma Cell ◽

Insulinoma Cell Line ◽

Ubiquitin Proteasome ◽

Proteasome Pathway ◽

Rat Insulinoma Cell Line ◽

Rat Insulinoma

Abstract Menin is encoded by multiple endocrine neoplasia type 1 (MEN1) gene, the germ line mutations of which are the main cause of pancreatic neuroendocrine tumors (PNETs). To date, a large number of frameshift, nonsense and missense mutations of MEN1 have been identified to be responsible for part of MEN1-defficient PNETs patients due to truncation or rapid degradation of menin protein. However, the stability of the wild-type (WT) menin in PNETs is totally unknown. In the present study, we observed ubiquitination of WT menin in 293T cells by transfection of ectopic WT menin and HA-ubiquitin. As expected, either endogenous or ectopic WT menin is stable in 293T cells, whereas in INS-1 cells, a rat insulinoma cell line derived from PNETs, either endogenous or ectopic WT menin is rapidly degraded through ubiquitin-proteasome pathway. Furthermore, the degradation of WT menin is more rapid in the presence of serum. Our findings suggest that in part of PNETs patients with WT MEN1, a ubiquitin-proteasome system targeting menin is untimely activated.

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