Cell Membrane Disruption Stimulates NO/PKG Signaling and Potentiates Cell Membrane Repair in Neighboring Cells
Abstract
Resealing of a disrupted plasma membrane at the micron-diameter range requires Ca2+-regulated exocytosis. Repeated membrane disruptions reseal more quickly than the initial wound, and this potentiation of membrane resealing persists for at least 24 hours after the initial wound. Long-term potentiation of membrane resealing requires CREB-dependent gene expression, which is activated by the PKC- and p38 MAPK-dependent pathway in a wounded cell. The present study demonstrates that membrane resealing is potentiated in both wounded and neighboring cells in MDCK cells. Wounding of cells expressing CREB133, a mutant variant of CREB, does not show the potentiated response of cell membrane resealing in either wounded or neighboring cells. Furthermore, wounding of cells induces CREB phosphorylation, not only in wounded cells, but also in neighboring cells. Inhibition of the nitric oxide/PKG signaling pathway suppresses CREB phosphorylation in neighboring cells, but not in wounded cells. The potentiation of membrane resealing in neighboring cells is suppressed if the nitric oxide/PKG pathway is inhibited during the initial wound. Together, these results suggest that the nitric oxide/PKG pathway stimulates CREB phosphorylation in neighboring cells so that subsequent cell membrane disruptions of the neighboring cells reseal more quickly.Citation
PLoS One. 2012 Aug 7; 7(8):e42885Scopus Count
Related items
Showing items related by title, author, creator and subject.
-
Hydroxyurea induces fetal hemoglobin expression by activating cAMP signaling pathways in a cAMP- and cGMP-dependent mannerHere we show that hydroxyurea (HU) induces fetal hemoglobin (HbF) expression by activating the cAMP pathway through two independent mechanisms. Although HU increased both cAMP and cGMP levels in CD34+-derived erythroblasts, only the cAMP pathway was found to be activated. However, HU-induced HbF expression was affected by the activities of both adenylate cyclase (AC) and soluble guanylate cyclase (sGC). HU decreased the expression of cGMP-inhibitable phosphodiesterase (PDE) 3B in a sGC-dependent manner, resulting in activation of the cAMP pathway. Second, HU induced the expression of cyclooxygenase-1 (COX-1) and increased the production of prostaglandin E2 (PGE2), which resulted in activation of the cAMP signaling pathway through AC. HU therapy elevated plasma PGE2 levels in sickle cell patients. These results demonstrate that HU induces HbF expression by activating the cAMP pathway via dual signaling mechanisms.
-
Does the JNK/Jun Signaling Node Regulate Autophagy in Breast Cancer Cells?A common treatment for estrogen receptor positivebreast cancers is the use of selective estrogen receptor modulators such as Tamoxifen.1Unfortunately, 30-40% of patients experience relapse due tothe development ofantiestrogen resistance. Autophagy, a process that is typically seen in cells that are exposed to a variety of stresses, is critical to development of antiestrogen resistanceand may play a key role in metastatic progression.2,3 To further combat antiestrogen resistance, a potential target for breast cancers is JNK (c-Jun N-terminal kinase), a member of the mitogen-activated protein kinase (MAPK) family. The mechanismsby which JNK inhibition affects breast cancer cell growthare not fully characterized.Our hypothesis is that JNK is a key regulator of autophagy and the emergence of autophagy-dependent antiestrogen resistant breast cancer. Our aims are todetermine the effect of JNK inhibition on autophagy, cell number, and cell viability under conditions of antiestrogen treatment.By utilizingMCF-7breast cancercells andthe irreversible JNK-IN-8 inhibitor our current data provides strong evidence that JNK inhibition blocks autophagy. Data supporting a role for JNK in the regulation of antiestrogen-mediated autophagy have the potential to identify JNK as a molecular target for the improved treatment of breast cancer.
-
p65fl/fl/LysMCre Transgenic Mouse Model Shows Altered Nf-Kb Signaling In MacrophagesWe have produced and begun characterizing a transgenic mouse model, p65fl/fl/LysMCre, that lacks canonical nuclear factor-kappaB (NF-kB) signaling (p65) in cells of the myeloid lineage, which includes macrophages. NF-kB pathway activity is very important in normal immune function, synaptic plasticity, and memory, and aberrant NF-kB activity is associated with autoimmune disease, and importantly, cancer. Macrophages can be present in very large numbers in a variety of cancers, and can lead to tumor progression through promotion of tumor inflammation, angiogenesis, invasion, and metastasis. This animal model will allow our group to pursue experiments involved in better understanding how stromal macrophages communicate with cancer cells through the NF-kB pathway, and how loss of canonical NF-kB signaling in cells of the myeloid lineage might weaken the tumor and make it more susceptible to standard treatments. Characterization of the model thus far reveals that p65 protein is indeed absent in macrophages derived from bone marrow monocytes, and that NF-kB signaling is altered when stimulated with lipopolysaccharide. We have just begun co-culture experiments with p65 deleted macrophages and glioma cells, and anticipate altered communication when compared to culture with control macrophages. Funding Source: Cancer Center Collaboration Grant
