GTP-dependent Secretion from Neutrophils Is Regulated by Cdk5

Rosales, Jesusa L.; Ernst, Joel D.; Hallows, Janice L.; Lee, Ki-Young

doi:10.1074/jbc.m408467200

Cited by 40 publications

(38 citation statements)

References 36 publications

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“…This implies that CDK5-p35 activity is required for optimum levels of GTP-induced secretion from primary (azurophil) and secondary (specific) granules [37,38]. We found no change in levels of CD11b localization (which resides in secondary granules) upon treatment with R-roscovitine when compared with control.…”

Section: Discussionmentioning

confidence: 59%

The cyclin‐dependent kinase inhibitor R‐roscovitine down‐regulates Mcl‐1 to override pro‐inflammatory signalling and drive neutrophil apoptosis

et al. 2010

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Successful resolution of inflammation requires inflammatory cells such as neutrophils to undergo apoptosis prior to non-inflammatory phagocytosis by professional phagocytes. Recently, cyclin-dependent kinase (CDK) inhibitors (e.g. R-roscovitine) have been shown to induce neutrophil apoptosis and enhance the resolution of inflammation. Interestingly, NF-jB and MAPK pathways and key endogenous survival proteins (typified by Mcl-1) are involved in the regulation of neutrophil apoptosis and, in cancer-cell lines, have been implicated as possible targets of CDK inhibitors. Here, we demonstrate that R-roscovitine over-rides TNF-a and LPS-induced survival (determined by morphological examination and binding of fluorescently labelled annexin-V) of isolated peripheral blood neutrophils. This effect did not appear to be mediated via effects on early markers of neutrophil activation (e.g. surface marker expression, shape change, aggregation and superoxide anion generation), by direct inhibition of NF-jB activation (assessed by cytoplasmic IjBa proteolysis and NF-jB p65 subunit translocation) and ERK activation (determined by specific ERK phosphorylation) but due to down-regulation (at protein and mRNA level) of the survival protein Mcl-1 but not the pro-apoptotic bcl-2 homologue Bim. These findings suggest that key endogenous survival proteins may be the targets of CDK inhibitors and consequently may be of critical importance in the resolution of inflammation.

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Section: Discussionmentioning

confidence: 59%

The cyclin‐dependent kinase inhibitor R‐roscovitine down‐regulates Mcl‐1 to override pro‐inflammatory signalling and drive neutrophil apoptosis

et al. 2010

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“…Cells were lysed using 1% IgepalCA-630 (Sigma) in TBS containing a protease inhibitor cocktail before centrifugation (23 100Âg; 4°C; 20 min) [24]. Protein samples (equivalent to 1.5 Â 10 6 cells/lane) were resolved by SDS-PAGE (12% gel Thermo Scientific) then transferred to PVDF membranes (Millipore).…”

Section: Western Blottingmentioning

confidence: 99%

“…Eosinophils are terminally differentiated cells and as such should not require cell-cycling machinery such as CDKs. Nonetheless, like other terminally differentiated cells, including neutrophils [24,25] and neurons [26], they have measurable expression of CDKs. Neutrophils are known to undergo apoptosis in response to CDK inhibitors and indeed work performed in our laboratory has shown that resolution of neutrophil-driven inflammation can be driven by this class of drugs [27].…”

Section: Introductionmentioning

confidence: 99%

The CDK inhibitor, R‐roscovitine, promotes eosinophil apoptosis by down‐regulation of Mcl‐1

Duffin¹,

Leitch²,

Sheldrake³

et al. 2009

FEBS Letters

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a b s t r a c tEosinophils are major players in inflammatory allergic diseases such as asthma, hay fever and eczema. Here we show that the cyclin-dependent kinase inhibitor (CDKi) R-roscovitine efficiently and rapidly induces human eosinophil apoptosis using flow cytometric analysis of annexin-V/propidium iodide staining, morphological analysis by light microscopy, transmission electron microscopy and Western immunoblotting for caspase-3 cleavage. We further dissect these observations by demonstrating that eosinophils treated with R-roscovitine lose mitochondrial membrane potential and the key survival protein Mcl-1 is down-regulated. This novel finding of efficacious induction of eosinophil apoptosis by CDKi drugs has potential as a strategy for driving resolution of eosinophilic inflammation.

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“…Initial implication resulted from the finding that Cdk5 phosphorylation of Munc-18 causes dissociation of the latter from syntaxin 1, which then associates with other SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins to promote secretion (Shuang et al, 1998). In neutrophils, we previously found that Cdk5 activity is required to elicit the maximum GTP-induced secretory response (Rosales et al, 2004a). Our premise is that Cdk5 is involved in vimentin dynamics during GTP-induced secretion by neutrophils.…”

Section: Discussionmentioning

confidence: 99%

“…Although Cdk5 activity has mostly been associated with brain, more recent studies indicate that Cdk5 plays an important role in other tissues as well such as muscle (Sahlgren et al, 2003), ocular lens (Gao et al, 2002) and testis (Rosales et al, 2004b). It appears that Cdk5 regulates cell differentiation and certain specialized cell functions (Rosales and Lee, 2006), including wound healing (Gao et al, 2004), gene transcription (Fu et al, 2004), senescence (Alexander et al, 2004), and secretion (Rosales et al, 2004a).…”

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confidence: 99%

Cdk5 mediates vimentin ser56 phosphorylation during GTP‐induced secretion by neutrophils

Lee

Liu

Jin

et al. 2011

Journal Cellular Physiology

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Secretion by neutrophils contributes to acute inflammation following injury or infection. Vimentin has been shown to be important for secretion by neutrophils but little is known about its dynamics during secretion, which is regulated by cyclin-dependent kinase 5 (Cdk5). In this study, we sought to examine the vimentin dynamics and its potential regulation by Cdk5 during neutrophil secretion. We show that vimentin is a Cdk5 substrate that is specifically phosphorylated at Ser56. In response to neutrophil stimulation with GTP, vimentin Ser56 was phosphorylated and colocalized with Cdk5 in the cytoplasmic compartment. Vimentin pSer56 and Cdk5 colocalization was consistent with coimmunoprecipitation from stimulated cells. Vimentin Ser56 phosphorylation occurred immediately after stimulation, and a remarkable increase in phosphorylation was noted later in the secretory process. Decreased GTP-induced vimentin Ser56 phosphorylation and secretion resulted from inhibition of Cdk5 activity by roscovitine or olomoucine or by depletion of Cdk5 by siRNA, suggesting that GTP-induced Cdk5-mediated vimentinSer56 phosphorylation may be related to GTP-inducedCdk5-mediated secretion by neutrophils. Indeed, inhibition of vimentin Ser56 phosphorylation led to a corresponding inhibition of GTP-induced secretion, indicating a link between these two events. While fMLP also induced vimentin Ser56 phosphorylation, such phosphorylation was unaffected by roscovitine, which nonetheless, inhibited secretion, suggesting that Cdk5 regulates fMLP-induced secretion via a mechanism independent of Cdk5-mediated vimentin Ser56 phosphorylation. These findings demonstrate the distinct involvement of Cdk5 in GTP-and fMLP-induced secretion by neutrophils, and support the notion that specific targeting of Cdk5 may serve to inhibit the neutrophil secretory process.The neutrophil is the first cell type recruited to a site of infection or inflammation. One of the mechanisms used by the neutrophil to destroy infectious agents or to mediate the inflammatory process in a variety of clinical scenarios is to secrete its granule contents. Regulation of secretion from the neutrophil is key to the balance between host defense and tissue injury (Nathan, 2006 CIHR Author ManuscriptCIHR Author Manuscript CIHR Author Manuscript independent GTP-regulated mechanism of secretion in neutrophils (Rosales and Ernst, 2000). Other nucleotide-mediated mechanisms of activation in neutrophils such as adenosine-5′-triphosphate (ATP)-and uridine-5′-triphosphate (UTP)-induced stimulation have been shown to be regulated by protein kinases, including the p38 mitogen-activated protein kinase (p38MAPK) and the extracellular signal-regulated kinase (ERK1/2) (Meshki et al., 2004). Our studies showed that GTP-dependent secretion from neutrophils is mediated by cyclin-dependent kinase 5 (Cdk5) (Rosales et al., 2004a). However, the mechanisms underlying this process remain to be investigated.Cdk5, a small proline-directed serine/threonine kinase, has close structural homology with...

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GTP-dependent Secretion from Neutrophils Is Regulated by Cdk5

Cited by 40 publications

References 36 publications

The cyclin‐dependent kinase inhibitor R‐roscovitine down‐regulates Mcl‐1 to override pro‐inflammatory signalling and drive neutrophil apoptosis

The cyclin‐dependent kinase inhibitor R‐roscovitine down‐regulates Mcl‐1 to override pro‐inflammatory signalling and drive neutrophil apoptosis

The CDK inhibitor, R‐roscovitine, promotes eosinophil apoptosis by down‐regulation of Mcl‐1

Cdk5 mediates vimentin ser56 phosphorylation during GTP‐induced secretion by neutrophils

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