Expression and regulation of c-Jun N-terminal kinase (JNK) in endometrial cells in vivo and in vitro

Sex and dose-dependent antinociceptive effects of the JNK (c-Jun N-terminal kinase) inhibitor SU 3327 are mediated by CB2 receptors in female, and CB1/CB2 receptors in male mice in an inflammatory pain model

Activation of c-Jun N-terminal kinases (JNKs) has been implicated in the development and persistence of inflammatory and neuropathic pain in animal models. Moreover, JNKs have been involved in the maintenance of chronic pain, as well as development of tolerance to antinociceptive agents in the opioid and cannabinoid class of compounds. In this study, we evaluated the antinociceptive effects of the JNK inhibitor SU 3327 (0.3-30 mg/kg) in the formalin pain model with an emphasis on the sex-specific actions of this compound. In wild-type C57BL6J mice, SU 3327 produced strong antinociceptive effects in the formalin pain model which were mediated by CB₂ receptors in females, and both CB₁ and CB₂ receptors in males. SU 3327 at a dose of 10 mg/kg produced antinociception, hypothermia, motor impairment, and hypolocomotion to a similar extent in both males and females. The antinociceptive effects of SU 3327 were more potent in males at lower doses (1 and 3 mg/kg), while females were more sensitive to the hypothermic, and motor-suppression effects at lower (3 mg/kg) doses versus males. Analysis of spinal cords, using qPCR following SU 3327 administration in the formalin test, revealed changes in cannabinoid, tolerance and inflammatory markers in females only, and only in the high (10-30 mg/kg) dose conditions. Indeed, females showed an increase in mRNA levels of cannabinoid (CB₂), but a decrease in tolerance (β-arrestin 1) and inflammatory (TNF-α, IL-1β, IL-6)-associated markers. The differences between males and females, in this study, support sex as an important factor in nociception and antinociceptive responses mediated by JNK and the endocannabinoid system.

Stress-Induced Evolutionary Innovation: A Mechanism for the Origin of Cell Types

Understanding the evolutionary role of environmentally induced phenotypic variation (i.e., plasticity) is an important issue in developmental evolution. A major physiological response to environmental change is cellular stress, which is counteracted by generic stress reactions detoxifying the cell. A model, stress-induced evolutionary innovation (SIEI), whereby ancestral stress reactions and their corresponding pathways can be transformed into novel structural components of body plans, such as new cell types, is described. Previous findings suggest that the cell differentiation cascade of a cell type critical to pregnancy in humans, the decidual stromal cell, evolved from a cellular stress reaction. It is hypothesized that the stress reaction in these cells was elicited ancestrally via inflammation caused by embryo attachment. The present study proposes that SIEI is a distinct form of plasticity-based evolutionary change leading to the origin of novel structures rather than adaptive transformation of pre-existing characters.

Selected Phytoestrogens Distinguish Roles of ERα Transactivation and Ligand Binding for Anti-Inflammatory Activity

Estrogen receptor α (ERα) is a ligand-activated transcriptional activator that is also involved vascular inflammation and atherosclerosis. Whether different ligands may affect this activity has not been explored. We screened a panel of phytoestrogens for their role in ERα binding and transcriptional transcription, and correlated the findings to anti-inflammatory activities in vascular endothelial cells stably expressing either a wild-type or mutant form of ERα deficient in its membrane association. Taxifolin and silymarin were "high binders" for ERα ligand binding; quercetin and curcumin were "high activators" for ERα transactivation. Using these phytoestrogens as functional probes, we found, in endothelial cells expressing wild-type ERα, the ERα high activator, but not the ERα high binder, promoted ERα nuclear translocation, estrogen response element (ERE) reporter activity, and the downstream gene expression. In endothelial cells expressing membrane association-deficient mutant ERα, the ERα nuclear translocation was significantly enhanced by taxifolin and silymarin, which still failed to activate ERα. Inflammation response was examined using the systemic or vascular inflammation inducers lipopolysaccharide or oxidized low-density lipoprotein. In both cases, only the ERα high activator inhibited nuclear translocation of nuclear factor κB, JNK, and p38, and the production of inflammatory cytokines IL-1β and TNFα. We confirm a threshold nuclear accumulation of ERα is necessary for its transactivation. The anti-inflammatory activity of phytoestrogens is highly dependent on ERα transactivation, less so on the ligand binding, and independent of its membrane association. A pre-examination of phytoestrogens for their mode of ERα interaction could facilitate their development as better targeted receptor modifiers.

Changes in nociceptin/orphanin FQ levels in rat brain regions after acute and chronic cannabinoid treatment in conjunction with the development of antinociceptive tolerance

It has been indicated that acute and chronic morphine administrations enhance nociceptin/orphanin FQ (N/OFQ) levels in the brain, which might play role in the development of tolerance to the antinociceptive effect of morphine. Accordingly, N/OFQ receptor (NOP) antagonists have been shown to prevent the development of antinociceptive tolerance to morphine. Our aim is to observe whether cannabinoids, similarly to opioids, enhance N/OFQ levels in pain-related brain regions and whether antagonism of NOP receptors attenuates the development of tolerance to the antinociceptive effect of cannabinoids. Hot plate and Tail flick tests are used to assess the antinociceptive response in Sprague-Dawley rats. N/OFQ levels are measured in cortex, amygdala, hypothalamus, periaqueductal gray, nucleus raphe magnus and locus coeruleus of rat brains using Western blotting and immunohistochemistry. Within 9 days, animals became completely tolerant to the antinociceptive effect of the cannabinoid agonist WIN 55,212-2 (2, 4, 6 mg/kg, i.p.). Chronic administration of JTC-801, a NOP receptor antagonist, at a dose that exerted no effect on its own (1 mg/kg, i.p.), attenuated development of tolerance to the antinociceptive effect of WIN 55,212-2 (4 mg/kg, i.p.). Western blotting and immunohistochemistry results showed that N/OFQ levels significantly increased in amygdala, periaqueductal gray, nucleus raphe magnus and locus coeruleus of rat brains when WIN 55,212-2 was combined with JTC-801. We hypothesize that, similar to opioids, chronic cannabinoid + NOP antagonist administration may enhance N/OFQ levels and NOP receptor antagonism prevents development of tolerance to cannabinoid antinociception.

Endometriosis: hormone regulation and clinical consequences of chemotaxis and apoptosis

BACKGROUND

The recruitment of immune cells by chemokines and the regulation of endometrial cell apoptosis are critical aspects of endometriosis biology. Here, we review the local (paracrine) and systemic hormone (endocrine) modulation of these two specific, but highly related phenomena.

METHODS

We searched Pubmed for items published in English between September 1991 and September 2011 and selected the studies evaluating the effects of hormones on chemokines or apoptosis in normal human endometrium and endometriosis.

RESULTS

Estradiol has proinflammatory and antiapoptotic effects in endometrial cells, and these effects appear to be exacerbated in women with endometriosis. In these women, physiological estradiol concentrations are able to induce an enhanced inflammatory response mediated by local chemokine production and to reinforce mechanisms of cell survival mediated by extracellular signal-regulated kinases and Bcl-2. The main effect of progestogens is to inhibit interleukin-8 and other chemokines in stromal cells from both eutopic and ectopic endometrium. Progesterone is also effective in inducing apoptosis in endometrial and endometriotic cells through the inhibition of Bcl-2 and nuclear factor-κB.

CONCLUSIONS

Estrogens and progestogens modulate chemotaxis and apoptosis in human endometrium and endometriotic cells and tissues. These endocrine and paracrine pathways are perturbed in women with endometriosis, contributing to inflammatory responses, abnormal tissue remodeling, therapeutic refractoriness and disease persistence. Ultimately, they promote adhesion formation and the clinical symptoms of pelvic pain and infertility. A more detailed understanding of the molecular mechanisms involved will offer new opportunities for novel pharmacological strategies to diagnose and treat endometriosis.

Increased JNK in males compared with females in a rodent model of abdominal aortic aneurysm

BACKGROUND

In humans, there is a 4:1 male:female ratio in the incidence of abdominal aortic aneurysms (AAAs). c-Jun-N-terminal kinase (JNK) is an important upstream regulator of several enzymes involved in AAA formation, including the matrix metalloproteinases (MMPs). The purpose of this study was to determine if there is a gender difference between males and females in JNK during AAA formation.

MATERIALS AND METHODS

Male and female C57/B6 mice underwent aortic perfusion with elastase or heat inactivated elastase with aortas harvested at d 3 and 14 for phenotype determination, RT-PCR, Western blot, and zymography. Additionally, in vitro experiments using siRNA were conducted to define JNK regulation of matrix metalloproteinases (MMPs). A t-test was used to compare between groups.

RESULTS

Males formed larger AAAs at d 14 compared with females (P < 0.001), with significantly higher levels of JNK1 protein, proMMP9, proMMP2, and active MMP2. At d 3, males had more JNK1 mRNA, protein, and MMP activity. Knockdown of JNK 1 or 2 in vitro decreased MMP activity, while knockdown of JNK 1 and 2 together blocked all MMP activity.

CONCLUSION

Alterations in JNK between genders is partially responsible for the differential rates of experimental AAA formation, likely through differential regulation of MMPs.

Inhibition of c-Jun N-terminal kinase attenuates low shear stress-induced atherogenesis in apolipoprotein E-deficient mice

Atherosclerosis begins as local inflammation of arterial walls at sites of disturbed flow, such as vessel curvatures and bifurcations with low shear stress. c-Jun NH₂-terminal kinase (JNK) is a major regulator of flow-dependent gene expression in endothelial cells in atherosclerosis. However, little is known about the in vivo role of JNK in low shear stress in atherosclerosis. We aimed to observe the effect of JNK on low shear stress-induced atherogenesis in apolipoprotein E-deficient (ApoE(-/-)) mice and investigate the potential mechanism in human umbilical vein endothelial cells (HUVECs). We divided 84 male ApoE(-/-) mice into two groups for treatment with normal saline (NS) (n = 42) and JNK inhibitor SP600125 (JNK-I) (n = 42). Perivascular shear stress modifiers were placed around the right carotid arteries, and plaque formation was studied at low shear stress regions. The left carotid arteries without modifiers represented undisturbed shear stress as a control. The NS group showed atherosclerotic lesions in arterial regions with low shear stress, whereas the JNK-I group showed almost no atherosclerotic lesions. Corresponding to the expression of proatherogenic vascular cell adhesion molecule 1 (VCAM-1), phospho-JNK (p-JNK) level was higher in low shear stress regions with NS than with JNK-I inhibitor. In HUVECs under low shear stress, siRNA knockdown and SP600125 inhibition of JNK attenuated nuclear factor (NF)-κB activity and VCAM-1 expression. Furthermore, siRNA knockdown of platelet endothelial cell adhesion molecule 1 (PECAM-1) (CD31) reduced p-JNK and VCAM-1 levels after low shear stress stimulation. JNK may play a critical role in low shear stress-induced atherogenesis by a PECAM-1-dependent mechanosensory pathway and modulating NF-κB activity and VCAM-1 expression.

Expression and role of interleukin-23 in human endometrium throughout the menstrual cycle and early pregnancy

Interleukin-23 (IL-23) is a novel cytokine involved in the regulation of organ-specific immune responses. We hypothesized that expression of IL-23 in the human endometrium is menstrual cycle and pregnancy dependent, and is involved in endometrial immune regulation. IL-23 expression and regulation was investigated in the human endometrium and placenta in vivo using immunohistochemistry and in vitro using Western blot and cell viability analyses. IL-23 immunoreactivity in endometrial glandular cells was highest in the late proliferative and early secretory phases, as compared to other cycle phases and first trimester tissues. Endometrial stromal cells (ESC) showed weak IL-23 immunoreactivity without significant changes in intensity and distribution throughout the menstrual cycle. First trimester decidual cells revealed significantly stronger IL-23 staining compared to ESC from non-pregnant endometrium. Both villous cytotrophoblasts and syncytiotrophoblasts also showed positive IL-23 immunoreactivity, with a higher staining in syncytiotrophoblasts. In the trophoblastic cell line HRT8, IL-23 expression increased in a time-dependent manner, but was undetectable in stromal cells under all treatment conditions. ESC treated with recombinant IL-23 showed significantly decreased IL-8 secretion and cell viability. These results suggest a possible regulatory role for IL-23 in the menstrual cycle and in early pregnancy, although the extent and function of this role are yet to be determined.

State-of-the-art technologies, current opinions and developments, and novel findings: news from the field of histochemistry and cell biology

Investigations of cell and tissue structure and function using innovative methods and approaches have again yielded numerous exciting findings in recent months and have added important data to current knowledge, inspiring new ideas and hypotheses in various fields of modern life sciences. Topics and contents of comprehensive expert reviews covering different aspects in methodological advances, cell biology, tissue function and morphology, and novel findings reported in original papers are summarized in the present review.