Tumor necrosis factor alpha (TNF) suppresses cAMP response element (CRE) activity and nuclear CRE binding protein in MA-10 mouse Leydig tumor cells

Targeting CREB in Cancer Therapy: A Key Candidate or One of Many? An Update

Intratumor heterogeneity (ITH) is considered the major disorienting factor in cancer treatment. As a result of stochastic genetic and epigenetic alterations, the appearance of a branched evolutionary shape confers tumor plasticity, causing relapse and unfavorable clinical prognosis. The growing evidence in cancer discovery presents to us "the great paradox" consisting of countless potential targets constantly discovered and a small number of candidates being effective in human patients. Among these, cyclic-AMP response element-binding protein (CREB) has been proposed as proto-oncogene supporting tumor initiation, progression and metastasis. Overexpression and hyperactivation of CREB are frequently observed in cancer, whereas genetic and pharmacological CREB downregulation affects proliferation and apoptosis. Notably, the present review is designed to investigate the feasibility of targeting CREB in cancer therapy. In particular, starting with the latest CREB evidence in cancer pathophysiology, we evaluate the advancement state of CREB inhibitor design, including the histone lysine demethylases JMJD3/UTX inhibitor GSKJ4 that we newly identified as a promising CREB modulator in leukemia cells. Moreover, an accurate analysis of strengths and weaknesses is also conducted to figure out whether CREB can actually represent a therapeutic candidate or just one of the innumerable preclinical cancer targets.

Glucagon-like peptide-1 suppresses neuroinflammation and improves neural structure

Glucagon-like peptide-1 (GLP-1) is a hormone mainly secreted from enteroendocrine L cells. GLP-1 and its receptor are also expressed in the brain. GLP-1 signaling has pivotal roles in regulating neuroinflammation and memory function, but it is unclear how GLP-1 improves memory function by regulating neuroinflammation. Here, we demonstrated that GLP-1 enhances neural structure by inhibiting lipopolysaccharide (LPS)-induced inflammation in microglia with the effects of GLP-1 itself on neurons. Inflammatory secretions of BV-2 microglia by LPS aggravated mitochondrial function and cell survival, as well as neural structure in Neuro-2a neurons. In inflammatory condition, GLP-1 suppressed the secretion of tumor necrosis factor-alpha (TNF-α)-associated cytokines and chemokines in BV-2 microglia and ultimately enhanced neurite complexity (neurite length, number of neurites from soma, and secondary branches) in Neuro-2a neurons. We confirmed that GLP-1 improves neurite complexity, dendritic spine morphogenesis, and spine development in TNF-α-treated primary cortical neurons based on altered expression levels of the factors related to neurite growth and spine morphology. Given that our data that GLP-1 itself enhances neurite complexity and spine morphology in neurons, we suggest that GLP-1 has a therapeutic potential in central nervous system diseases.

Infliximab abrogates cadmium-induced testicular damage and spermiotoxicity via enhancement of steroidogenesis and suppression of inflammation and apoptosis mediators

Cadmium(Cd) is a serious environmental and occupational contaminant that represents a serious health hazard to humans and other animals. Reproductive health problems have been reported in men exposed to Cd. Testicular damage is one of the deleterious effects due to Cd exposure. Cd-induced testicular toxicity is mediated through oxidative stress, inflammation, testosterone inhibition and apoptosis. Thus, the present study was performed to assess the possible protective role of infliximab (IFX), anti-TNFα agent, against Cd-induced testicular damage and spermiotoxicity in rats. The rats were randomly allotted into six experimental groups: control, Cd sulphate treated, Cd sulphate treated with infliximab (5 mg/kg), Cd sulphate with infliximab (7 mg/kg), infliximab alone (5 mg/kg), and infliximab alone (7 mg/kg). The control group received saline. To induce testicular damage, Cd sulphate (1.5 mg/100 gm body weight/day) was dissolved in normal saline and orally administrated for 3 consecutive weeks. The rats in infliximab-treated groups were given a weekly dose of 5 mg/kg/week or 7 mg/kg/week of infliximab intraperitoneally. In the current study Cd exposure reduced sperm count, markers of testicular function, sperm motility as well as gene expression of testicular 3β-HSD and 17β-HSD and serum testosterone level. Additionally, it increased testicular oxidative stress, inflammatory and apoptotic markers. The histopathologic studies supported the biochemical findings. Treatment with infliximab significantly attenuated Cd-induced injury verified by the restoration of testicular architecture, enhancement of steroidogenesis, preservation of spermatogenesis, modulation of the inflammatory reaction along with suppression of oxidative stress and apoptosis. It was concluded that infliximab, through its antioxidant, anti-inflammatory and anti-apoptotic effects, represents a potential therapeutic option to protect the testicular tissue from the detrimental effects of Cd.

Activation of β2-Adrenoceptor Attenuates Sepsis-Induced Hippocampus-Dependent Cognitive Impairments by Reversing Neuroinflammation and Synaptic Abnormalities

Sepsis-associated encephalopathy induces cognitive dysfunction via mechanisms that commonly involve neuroinflammation and synaptic plasticity impairment of the hippocampus. The β2-adrenoceptor (β2-AR) is a G-protein coupled receptor that regulates immune response and synaptic plasticity, whereas its dysfunction has been implicated in various neurodegenerative diseases. Thus, we hypothesized abnormal β2-AR signaling is involved in sepsis-induced cognitive impairment. In the present study, C57BL/6 mice were subjected to cecal ligation and puncture (CLP) to mimic the clinical human sepsis-associated encephalopathy. The levels of hippocampal β2-AR, proinflammatory cytokines tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), IL-6, cAMP-response element binding protein (CREB), brain derived neurotrophic factor (BDNF), post-synaptic density protein 95 (PSD95), and NMDA receptor 2 B subtypes (GluN2B) were determined at 6, 12, 24 h and 7 and 16 days after CLP. For the interventional study, mice were treated with β2-AR agonist clenbuterol in two ways: early treatment (immediately following CLP) and delayed treatment (on the 8th day following CLP). Neurobehavioral performances were assessed by open field and fear conditioning tests. Here, we found that hippocampal β2-AR expression was significantly decreased starting from 12 h and persisted until 16 days following CLP. Besides, sepsis mice also exhibited increasing neuroinflammation, down-regulated CREB/BDNF, decreasing PSD95 and GluN2B expression, and displayed hippocampus-dependent cognitive impairments. Notably, early clenbuterol treatment alleviated sepsis-induced cognitive deficits by polarizing microglia toward an anti-inflammatory phenotype, reducing proinflammatory cytokines including IL-1β, TNF-α, and up-regulating CREB/BDNF, PSD95, and GluN2B. Intriguingly, delayed clenbuterol treatment also improved cognitive impairments by normalization of hippocampal CREB/BDNF, PSD95, and GluN2B. In summary, our results support the beneficial effects of both early and delayed clenbuterol treatment, which suggests that activation of β2-AR has a translational value in sepsis-associated organ dysfunction including cognitive impairments.

Hormonal regulation and function of an RNA helicase, Ddx5 in corpus luteum of adult Wistar rats

Corpus luteum (CL) is an endocrine tissue involved in regulation of reproductive cycle and early pregnancy establishment. In the present study DEAD-box helicase-5 (Ddx5), a member of the DEAD box family of RNA helicases was investigated for its expression, regulation and function in CL of Wistar rats. Ddx5 was expressed in adult rat CL. Primary cell culture from supra-ovulated ovaries were established for in vitro studies. Addition of luteinizing hormone (LH; 100 ng/ml), a luteotrophic factor in primary cell culture, decreased Ddx5 RNA expression (foldchange:0.6 ± 0.075) while prostaglandin alpha (PGF_2α; 1μM), a luteolytic factor caused an increase (foldchange:2.4 ± 0.4) compared to control group. Under in vivo conditions, the administration of PGF_2α or gonadotropin-releasing hormone antagonist; cetrorelix (CET) caused luteolysis as well as an increase in the protein level of Ddx5 (foldchange:1.9 ± 0.27 and 1.4 ± 0.09 viz.; p < 0.05) in CL of adult rats. LH was administered post CET treatment which suppressed Ddx5 protein expression (foldchange:0.8 ± 0.16; p < 0.05) compared to CET treated group. Further, it was observed that the expression of Ddx5 was upregulated (foldchange:1.5 ± 0.23; p < 0.05) in CL during late pregnancy compared to mid pregnancy concomitant to luteolysis in adult rats. Overall, the results suggest for the first time that Ddx5 is expressed in rat CL and regulated by luteolytic and luteotrophic factors in an inverse fashion. Further, the data significantly correlates ddx5 expression to CL regression suggesting involvement of ddx5 in luteolysis. These results suggest a significant role of Ddx5 in female reproduction biology and warrant in depth examination of the function of Ddx5 in CL.

Resveratrol abrogates lipopolysaccharide-induced depressive-like behavior, neuroinflammatory response, and CREB/BDNF signaling in mice

Current evidence supports that depression is accompanied by the activation of the inflammatory-response system, and overproduction of pro-inflammatory cytokines may play a role in the pathophysiology of depressive disorders. Resveratrol has anti-inflammatory, antioxidant and anti-depressant-like properties. Using an animal model of depression induced by a single administration of lipopolysaccharide (LPS), the present study investigated the effects of resveratrol on LPS-induced depressive-like behavior and inflammatory-response in adult mice. Our results showed that pretreatment with resveratrol (80mg/kg, i.p.) for 7 consecutive days reversed LPS-increased the immobility time in the forced swimming test and tail suspension test, and LPS-reduced sucrose preference test. Moreover, the antidepressant action of resveratrol was paralleled by significantly reducing the expression levels of pro-inflammatory cytokines, and up-regulating phosphorylated cAMP response-element-binding protein (pCREB)/brain-derived neurotrophic factor (BDNF) expression in prefrontal cortex (PFC) and hippocampus. In addition, resveratrol ameliorated LPS-induced NF-κB activation in the PFC and hippocampus. The results demonstrate that resveratrol may be an effective therapeutic agent for LPS-induced depressive-like behavior, partially due to its anti-inflammatory aptitude and by modulating pCREB and BDNF expression in the brain region of mice.

The hippocampus and TNF: Common links between chronic pain and depression

Major depression and chronic pain are significant health problems that seriously impact the quality of life of affected individuals. These diseases that individually are difficult to treat often co-exist, thereby compounding the patient's disability and impairment as well as the challenge of successful treatment. The development of efficacious treatments for these comorbid disorders requires a more comprehensive understanding of their linked associations through common neuromodulators, such as tumor necrosis factor-α (TNFα), and various neurotransmitters, as well as common neuroanatomical pathways and structures, including the hippocampal brain region. This review discusses the interaction between depression and chronic pain, emphasizing the fundamental role of the hippocampus in the development and maintenance of both disorders. The focus of this review addresses the hypothesis that hippocampal expressed TNFα serves as a therapeutic target for management of chronic pain and major depressive disorder (MDD).

Mapping the transcriptional machinery of the IL-8 gene in human bronchial epithelial cells

IL-8 released from bronchial epithelial cells infected with Pseudomonas aeruginosa plays a crucial role in the chronic lung pathology of patients affected by cystic fibrosis. Novel anti-inflammatory approaches will benefit from a thorough understanding of the regulatory mechanisms involved in the transcription of this chemokine to identify potential pharmacological targets. We addressed this issue by investigating the role of phosphoproteins and transcription factors (TFs) on transcription of IL-8 gene in the human bronchial epithelial IB3-1, CuFi-1, and Calu-3 cells. P. aeruginosa increased the basal phosphorylation of the ERK1/2 pathway components 90-kDa ribosomal S6 kinase (RSK)1/2 and mitogen- and stress-activated kinase-2 and of the p38 MAPK pathway components p38α/δ/γ and heat shock protein 27 (HSP27). The involvement of these kinases in the expression of IL-8 gene was confirmed with pharmacological inhibitors of ERK1/2, RSK, p38, and HSP27 both at transcription and secretion levels. Transfection of TF decoy oligodeoxynucleotides, designed to interfere with the interaction of the TFs NF-κB, NF-IL6, AP-1, CREB, and CHOP with the corresponding consensus sequences identified in the IL-8 promoter, reduced the P. aeruginosa-dependent transcription of IL-8, suggesting their participation in the transcriptional machinery. Stimulation of IB3-1 cells with IL-1β led to a similar pattern of activation, whereas the pattern of phosphoproteins and of TFs modulated by TNF-α differentiated sharply. In conclusion, the results highlight a novel role for RSK1/2 and HSP27 phosphoproteins and of the cooperative role of the TFs NF-κB, NF-IL6, AP-1, CHOP, and CREB in P. aeruginosa-dependent induction of transcription of the IL-8 gene in human bronchial epithelial cells.

IL-1beta stimulates activin betaA mRNA expression in human skin fibroblasts through the MAPK pathways, the nuclear factor-kappaB pathway, and prostaglandin E2

During mouse skin wound healing, mRNAs encoding IL-1, activins, and TGF-βs significantly increased. To elucidate involvement of IL-1 in the regulation of activins and related factors in the wounded skin, human foreskin fibroblasts were stimulated with IL-1β, and levels of mRNAs encoding activins, TGF-βs, and follistatin family proteins were examined by quantitative real-time PCR. IL-1β increased activin βA (INHBA) and follistatin (FST) mRNA expression within 6 h. A p38 MAPK inhibitor, SB202190, a MAPK/ERK kinase inhibitor, U0126, and an nuclear factor κB pathway inhibitor, SC-514, significantly suppressed the IL-1β-stimulated INHBA and FST mRNA expression. A prostaglandin-endoperoxide synthase inhibitor indomethacin, a potent inhibitor of prostaglandin E(2) (PGE(2)) synthesis, also significantly suppressed the IL-1β-stimulated INHBA but not FST mRNA expression. Furthermore, stimulation of fibroblasts with PGE(2) significantly increased INHBA mRNA. The PGE(2)-induced INHBA mRNA expression was significantly suppressed by U0126 and a protein kinase C inhibitor, Gö 6983. Although IL-1β stimulated FST mRNA in an acute phase, long-term exposure of fibroblasts to IL-1β revealed time-dependent stimulatory and inhibitory effects of IL-1β on FST mRNA expression. On the other hand, coculture with keratinocytes significantly increased INHBA mRNA expression in dermal equivalents. In summary, the present study indicates that the p38 MAPK, the MAPK/ERK kinase, the nuclear factor κB pathway, and PGE(2) mediate the effects of IL-1β on INHBA mRNA expression. Furthermore, it is indicated that keratinocyte-derived factor of factors stimulate INHBA mRNA expression during wound healing.