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

2012 ◽  
Vol 117 (2) ◽  
pp. 329-338 ◽  
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.

scholarly journals The effect of denervation on protein synthesis and degradation in adult rat diaphragm muscle

2009 ◽  
Vol 107 (2) ◽  
pp. 438-444 ◽  
Author(s):  
Heather M. Argadine ◽  
Nathan J. Hellyer ◽  
Carlos B. Mantilla ◽  
Wen-Zhi Zhan ◽  
Gary C. Sieck
Keyword(s):  
Protein Synthesis ◽  
Protein Degradation ◽  
Caspase 3 ◽  
Diaphragm Muscle ◽  
Rat Diaphragm ◽  
Ubiquitin Proteasome Pathway ◽  
Protein Ubiquitination ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway ◽  
Net Protein

Previous studies showed that unilateral denervation (DNV) of the rat diaphragm muscle (DIAm) results in loss of myosin heavy chain protein by 1 day after DNV. We hypothesize that DNV decreases net protein balance as a result of activation of the ubiquitin-proteasome pathway. In DIAm strips, protein synthesis was measured by incorporation of 3H-Tyr, and protein degradation was measured by Tyr release at 1, 3, 5, 7, and 14 days after DNV. Total protein ubiquitination, caspase-3 expression/activity, and actin fragmentation were analyzed by Western analysis. We found that, at 3 days after DNV, protein synthesis increased by 77% relative to sham controls. Protein synthesis remained elevated at 5 (85%), 7 (53%), and 14 days (123%) after DNV. At 5 days after DNV, protein degradation increased by 43% relative to sham controls and remained elevated at 7 (49%) and 14 days (74%) after DNV. Thus, by 5 days after DNV, net protein balance decreased by 43% compared with sham controls and was decreased compared with sham at 7 (49%) and 14 days (72%) after DNV. Protein ubiquitination increased at 5 days after DNV and remained elevated. DNV had no effect on caspase-3 activity or actin fragmentation, suggesting that the ubiquitin-proteasome pathway rather than caspase-3 activation is important in the DIAm response to DNV. Early loss of contractile proteins, such as myosin heavy chain, is likely the result of selective protein degradation rather than generalized protein breakdown. Future studies should evaluate this selective effect of DNV.

Heparin Fragments Induce Cervical Inflammation by Recruiting Immune Cells through Toll-like Receptor 4 in nonpregnant mice

2021 ◽  
Author(s):  
Anna Åkerud ◽  
Jakob Axelsson ◽  
Manisha Yadav ◽  
Jonas Erjefält ◽  
Gunvor Ekman-Ordeberg ◽  
...  
Keyword(s):  
Heparan Sulphate ◽  
Late Pregnancy ◽  
Primary Response ◽  
Cervical Ripening ◽  
Mucosal Inflammation ◽  
Toll Like Receptor ◽  
Wild Type ◽  
Toll Like Receptor 4 ◽  
Local Inflammatory Response ◽  
Deficient Mice

Abstract Inflammation is a hallmark in the human cervix remodelling. A possible candidate inducing the inflammatory driven ripening of the cervix is the matrix component heparan sulphate, which has been shown to be elevated in late pregnancy in the cervix and uterus. Heparin and a glycol-split low molecular weight heparin (gsHep) with low anticoagulant potency has been shown to enhance myometrial contraction and interleukin (IL)-8 production by cervical fibroblasts. The aim of this study was to investigate the mechanism by which heparin promotes cervical inflammation. Wild-type, Toll-like receptor 4 (TLR4), Myeloid differentiation primary response gene 88 n (MyD88) and Interferon regulatory factor 3 (IRF3)-deficient mice were treated by deposition of gsHep into the vaginas of nonpregnant mice. To identify which cells that responded to the heparin fragments, a rhodamine fluorescent construct of gsHep was used, which initially did bind to the epithelial cells and were at later time points located in the sub-mucosa. The heparin fragments induced a strong local inflammatory response in wild-type mice shown by a rapid infiltration of neutrophils and to a lesser extent macrophages into the epithelium and the underlying extracellular matrix (ECM) of the cervix. Further, a marked migration into the cervical and vaginal lumen was seen by both neutrophils and macrophages. The induced mucosal inflammation was strongly reduced in TLR4- and IRF3-deficient mice. In conclusion, our findings suggest that a TLR4/IRF3-mediated innate immune response in the cervical mucosa is induced by gsHep. This low anticoagulant heparin version, a novel TLR4 agonist, could contribute to human cervical ripening during the initiation of labour.

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

2004 ◽  
Vol 24 (15) ◽  
pp. 6569-6580 ◽  
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.

scholarly journals Impact of toll-like receptor 4 deficiency on the response to uterine ischemia/reperfusion in mice

Reproduction ◽  
2013 ◽  
Vol 145 (5) ◽  
pp. 517-526 ◽  
Author(s):  
Larry G Thaete ◽  
Xiao-Wu Qu ◽  
Tamas Jilling ◽  
Susan E Crawford ◽  
Philip Fitchev ◽  
...  
Keyword(s):  
Ischemia Reperfusion ◽  
Fetal Loss ◽  
Interleukin 10 ◽  
Myeloperoxidase Activity ◽  
Toll Like Receptor ◽  
Wild Type ◽  
Toll Like Receptor 4 ◽  
Lower Baseline ◽  
Tlr4 Ligand ◽  
Deficient Mice

Our objective was to determine the role of toll-like receptor 4 (TLR4) in uterine ischemia/reperfusion (I/R)-induced fetal growth restriction (FGR). Pregnant TLR4-deficient and wild-type mice were subjected to I/R or a sham procedure. Fetal and placental weights were recorded and tissues were collected. Pep-1 (inhibits low-molecular-weight hyaluronan (LMW-HA) binding to TLR4) was used to determine whether LMW-HA–TLR4 interaction has a role in FGR. TLR4-deficient mice exhibited significantly lower baseline fetal weights compared with wild-type mice (P<0.05), along with extensive placental calcification that was not present in wild-type mice. Following I/R, fetal and placental weights were significantly reduced in wild-type (P<0.05) but not in TLR4-deficient mice. However, I/R increased fetal loss (P<0.05) only in TLR4-deficient mice. Corresponding with the reduced fetal weights, uterine myeloperoxidase activity increased in wild-type mice (P<0.001), indicating an inflammatory response, which was absent in TLR4-deficient mice. TLR4 was shown to have a regulatory role for two anti-inflammatory cytokines: interferon-B1 decreased only in wild-type mice (P<0.01) and interleukin-10 increased only in TLR4-deficient mice (P<0.001), in response to I/R. Pep-1 completely prevented I/R-induced FGR (P<0.001), indicating a potential role for the endogenous TLR4 ligand LMW-HA in I/R-induced FGR. In conclusion, uterine I/R in pregnancy produces FGR that is dependent on TLR4 and endogenous ligand(s), including breakdown products of HA. In addition, TLR4 may play a role in preventing pregnancy loss after uterine I/R.

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

2020 ◽  
Vol 117 (37) ◽  
pp. 23106-23112
Author(s):  
Yuki Hirose ◽  
Tomohiro Kitazono ◽  
Maiko Sezaki ◽  
Manabu Abe ◽  
Kenji Sakimura ◽  
...  
Keyword(s):  
Resistant Mutant ◽  
Sleep Time ◽  
Similar Degree ◽  
General Anesthetics ◽  
Wild Type ◽  
Ubiquitin Proteasome Pathway ◽  
Hypnotic Effect ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway ◽  
Fos Expression

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.

Mechanical ventilation induces alterations of the ubiquitin-proteasome pathway in the diaphragm

2005 ◽  
Vol 98 (4) ◽  
pp. 1314-1321 ◽  
Author(s):  
Keith C. DeRuisseau ◽  
Andreas N. Kavazis ◽  
Melissa A. Deering ◽  
Darin J. Falk ◽  
Darin Van Gammeren ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Control Group ◽  
20S Proteasome ◽  
Mrna Levels ◽  
Α Subunit ◽  
Ubiquitin Proteasome Pathway ◽  
Ubiquitin Conjugating Enzyme ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway ◽  
Conjugating Enzyme

Prolonged mechanical ventilation (MV) results in diaphragmatic atrophy due, in part, to an increase in proteolysis. These experiments tested the hypothesis that MV-induced diaphragmatic proteolysis is accompanied by increased expression of key components of the ubiquitin-proteasome pathway (UPP). To test this postulate, we investigated the effect of prolonged MV on UPP components and determined the trypsin-like and peptidylglutamyl peptide hydrolyzing activities of the 20S proteasome. Adult Sprague-Dawley rats were assigned to either control or 12-h MV groups ( n = 7/group). MV animals were anesthetized, tracheostomized, and ventilated with room air for 12 h. Animals in the control group were acutely anesthetized but not exposed to MV. Compared with controls, MV animals demonstrated increased diaphragmatic mRNA levels of two ubiquitin ligases, muscle atrophy F-box (+8.3-fold) and muscle ring finger 1 (+19.0-fold). However, MV did not alter mRNA levels of 14-kDa ubiquitin-conjugating enzyme, polyubiquitin, proteasome-activating complex PA28, or 20S α-subunit 7. Protein levels of 14-kDa ubiquitin-conjugating enzyme and proteasome-activating complex PA28 were not altered following MV, but 20S α-subunit 7 levels declined (−17.7%). MV increased diaphragmatic trypsin-like activity (+31%) but did not alter peptidylglutamyl peptide hydrolyzing activity. Finally, compared with controls, MV increased ubiquitin-protein conjugates in both the myofibrillar (+24.9%) and cytosolic (+54.7%) fractions of the diaphragm. These results are consistent with the hypothesis that prolonged MV increases diaphragmatic levels of key components within the UPP and that increases in 20S proteasome activity contribute to MV-induced diaphragmatic proteolysis and atrophy.

Inhibition of Ubiquitin-Proteasome Pathway Causes Growth Suppression and Induces Apoptosis in Diffuse Large B Cell Lymphoma.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1571-1571
Author(s):  
Shahab Uddin ◽  
Azhar Hussain ◽  
Asma Khan ◽  
Prashant Bavi ◽  
Khawla Al-Kuraya
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Caspase 3 ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Ubiquitin Proteasome Pathway ◽  
Large B Cell Lymphoma ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway ◽  
Large B Cell

Abstract SKP2, an F-box protein targets cell cycle regulators including cycle-dependent kinase inhibitor p27KIP1 via ubiquitin-mediated degradation. SKP2 is frequently overexpressed in variety of cancer cells and has been implicated in oncogenesis, however its role in diffuse large B-cell lymphoma (DLBCL) has not been elucidated. Therefore, we investigated the role of SKP2 and its ubiquitin-proteasome pathway in DLBL using a panel of cell lines and clinical samples. MG132, a reversible and specific inhibitor of ubiquitin-proteasome pathway that acts through blocking ubiquitin-mediated proteolysis via binding to 20S and 26S proteasomes. Our study showed that treatment of DLBCL cell lines (SUDHL4, SUDHL5, SUDHL8 and OCILY19) with MG132 suppressed growth and induced apoptosis. Treatment of DLBCL cells with MG132 caused downregulation of SKP2, accumulation and stabilization of p27KIP1 leading to the apoptosis. Further downstream, MG132 induced activation of caspase-8 and cleavage of Bid subsequently leading to loss of mitochondrial membrane potential and release of cytochrome c from mitochondria into cytosol, resulting in activation of caspase-3 and cleavage of PARP. zVAD-fmk, a universal inhibitor of caspases prevented caspase-3 activation and abrogated apoptosis induced by MG132 treatment. Finally, using immunohistochemistry, SKP2 was detected in 94 (32.9%) of 286 DLBCL tumors. Furthermore, patients with high SKP2 expression were associated with high expression of Ki67, a proliferative marker. Altogether, these results suggest that SKP2 and ubiquitin-proteasome pathway may be a potential target for therapeutic intervention in diffuse large B-cell lymphoma.

scholarly journals Inhibition of ubiquitin-proteasome pathway activates a caspase-3-like protease and induces Bcl-2 cleavage in human M-07e leukaemic cells

1999 ◽  
Vol 340 (1) ◽  
pp. 127-133 ◽  
Author(s):  
Xue-min ZHANG ◽  
Hong LIN ◽  
Catheryne CHEN ◽  
Ben D.-M. CHEN
Keyword(s):  
Cell Death ◽  
Proteasome Inhibitor ◽  
Caspase 3 ◽  
Specific Inhibitor ◽  
Apoptotic Pathway ◽  
Principal Mechanism ◽  
Ubiquitin Proteasome Pathway ◽  
Gm Csf ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway

The ubiquitin-proteasome pathway is the principal mechanism for the degradation of short-lived proteins in eukaryotic cells. Here we examine the possibility that ubiquitin-proteasome is involved in regulating the levels of Bcl-2, which is abundantly expressed in M-07e cells, a granulocyte/macrophage colony-stimulating factor (GM-CSF)-dependent human leukaemic cell line. Apoptosis in M-07e cells, induced by GM-CSF withdrawal, was associated with a gradual cleavage of Bcl-2 into a 22 kDa fragment. Treatment of M-07e cells with benzyloxycarbonyl-Leu-Leu-L-leucinal (Z-LLL-CHO; MG-132), a reversible ubiquitin-proteasome inhibitor, markedly accelerated the cleavage of Bcl-2 and promoted cell death through the apoptotic pathway. The cleavage of Bcl-2 was inhibited by a caspase-3 (CPP32)-specific inhibitor [acetyl-Asp-Glu-Val-Asp-CHO (DEVD-CHO)] but not caspase 1 inhibitor (acetyl-Tyr-Val-Ala-Asp-CHO), suggesting that Bcl-2 is a proteolytic substrate of a caspase-3-like protease activated during apoptosis. The simultaneous addition of recombinant human GM-CSF (rhGM-CSF) to M-07e cultures delayed the activation of caspase 3 and Bcl-2 cleavage triggered by Z-LLL-CHO, suggesting that the activation of the GM-CSF signalling pathway can partly overcome the apoptotic effect induced by Z-LLL-CHO. Apoptosis induced by inhibition of the proteasome pathway was verified in studies with lactacystin, a highly specific and irreversible proteasome inhibitor. Lactacystin-induced apoptosis in M-07e cells was remarkably similar to that induced by Z-LLL-CHO, which included caspase 3 activation, cleavage of Bcl-2 into a 22 kDa fragment and, ultimately, cell death. These results showed that inhibition of the ubiquitin-proteasome pathways can lead to the activation of a DEVD-CHO-sensitive caspase and induces Bcl-2 cleavage, which might have a role in mediating apoptosis in M-07e cells.

scholarly journals Protective effects of guggulsterone against colitis are associated with the suppression of TREM-1 and modulation of macrophages

2018 ◽  
Vol 315 (1) ◽  
pp. G128-G139 ◽  
Author(s):  
Xiumei Che ◽  
Ki Cheong Park ◽  
Soo Jung Park ◽  
You Hyun Kang ◽  
Hyun A Jin ◽  
...  
Keyword(s):  
Inflammatory Bowel Disease ◽  
Bowel Disease ◽  
Myeloid Cells ◽  
Trinitrobenzene Sulfonic Acid ◽  
Toll Like Receptor ◽  
Wild Type ◽  
Toll Like Receptor 4 ◽  
Inflammatory Bowel ◽  
Deficient Mice ◽  
M2 Phenotype

Triggering receptor expressed on myeloid cells 1 (TREM-1)-expressing intestinal macrophages are significantly increased in the colons of patients with inflammatory bowel disease (IBD). We focused here on the effects of guggulsterone on macrophage modulation in colitis as a potential therapeutic molecule in human IBD and explore the underlying mechanisms. Gene expression in macrophages was examined and wound-healing assay using HT-29 cells was performed. Colitis in wild-type and IL-10-, Toll-like receptor 4 (TLR4)-, and myeloid differentiation primary response 88 (MyD88)-deficient mice was induced via the administration of 2,4,6-trinitrobenzene sulfonic acid (TNBS) into the colon. In both in vitro and in vivo experiments, guggulsterone suppressed intestinal inflammation amplified by TREM-1 stimulation, in which the suppression of NF-κB, activating protein-1, and proteasome pathways was involved. In the TNBS-induced colitis model, guggulsterone reduced disease activity index scores and TREM-1 expression, stimulated IL-10 production, and improved survival in wild-type mice. These effects were not observed in IL-10-, TLR4-, and MyD88-deficient mice. Guggulsterone also suppressed M1 polarization, yet induced the M2 phenotype in macrophages from IBD patients as well as from mice. These findings indicate that guggulsterone blocks the hyperactivation of macrophages via TREM-1 suppression and induces M2 polarization via IL-10 mediated by the TLR4 signaling pathway. Furthermore, this study provides a new rationale for the therapeutic potential of guggulsterone in the treatment of IBD. NEW & NOTEWORTHY We found that guggulsterone attenuates triggering receptor expressed on myeloid cells 1 (TREM-1)-mediated hyperactivation of macrophages and polarizes macrophages toward the M2 phenotype. This was mediated by IL-10 and partly Toll-like receptor 4 signaling pathways. Overall, these data support that guggulsterone as a natural plant sterol modulates macrophage phenotypes in colitis, which may be of novel therapeutic importance in inflammatory bowel disease treatment.

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