LKB1 controls inflammatory potential through CRTC2-dependent histone acetylation.

Deregulated inflammation is a critical feature driving the progression of tumors harboring mutations in the liver kinase B1 (LKB1), yet the mechanisms linking LKB1 mutations to deregulated inflammation remain undefined. Here, we identify deregulated signaling by CREB-regulated transcription coactivator 2 (CRTC2) as an epigenetic driver of inflammatory potential downstream of LKB1 loss. We demonstrate that LKB1 mutations sensitize both transformed and non-transformed cells to diverse inflammatory stimuli, promoting heightened cytokine and chemokine production. LKB1 loss triggers elevated CRTC2-CREB signaling downstream of the salt-inducible kinases (SIKs), increasing inflammatory gene expression in LKB1-deficient cells. Mechanistically, CRTC2 cooperates with the histone acetyltransferases CBP/p300 to deposit histone acetylation marks associated with active transcription (i.e., H3K27ac) at inflammatory gene loci, promoting cytokine expression. Together, our data reveal a previously undefined anti-inflammatory program, regulated by LKB1 and reinforced through CRTC2-dependent histone modification signaling, that links metabolic and epigenetic states to cell-intrinsic inflammatory potential.

From membrane to nucleus: A three-wave hypothesis of cAMP signaling.

For many decades, our understanding of G protein-coupled receptor (GPCR) activity and cyclic AMP (cAMP) signaling was limited exclusively to the plasma membrane. However, a growing body of evidence has challenged this view by introducing the concept of endocytosis-dependent GPCR signaling. This emerging paradigm emphasizes not only the sustained production of cAMP but also its precise subcellular localization, thus transforming our understanding of the spatiotemporal organization of this process. Starting from this alternative point of view, our recent work sheds light on the role of an endocytosis-dependent calcium release from the endoplasmic reticulum in the control of nuclear cAMP levels. This is achieved through the activation of local soluble adenylyl cyclase, which in turn regulates the activation of local protein kinase A (PKA) and downstream transcriptional events. In this review, we explore the dynamic evolution of research on cyclic AMP signaling, including the findings that led us to formulate the novel three-wave hypothesis. We delve into how we abandoned the paradigm of cAMP generation limited to the plasma membrane and the changing perspectives on the rate-limiting step in nuclear PKA activation.

N1-Acetyl-5-methoxykynuramine, which decreases in the hippocampus with aging, improves long-term memory via CaMKII/CREB phosphorylation.

Melatonin is a molecule ubiquitous in nature and involved in several physiological functions. In the brain, melatonin is converted to N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK) and then to N1-acetyl-5-methoxykynuramine (AMK), which has been reported to strongly enhance long-term object memory formation. However, the synthesis of AMK in brain tissues and the underlying mechanisms regarding memory formation remain largely unknown. In the present study, young and old individuals from a melatonin-producing strain, C3H/He mice, were employed. The amount of AMK in the pineal gland and plasma was very low compared with those of melatonin at night; conversely, in the hippocampus, the amount of AMK was higher than that of melatonin. Indoleamine 2, 3-dioxygenase (Ido) mRNA was expressed in multiple brain tissues, whereas tryptophan 2,3-dioxygenase (Tdo) mRNA was expressed only in the hippocampus, and its lysate had melatonin to AFMK conversion activity, which was blocked by the TDO inhibitor. The expression levels of phosphorylated cAMP response element binding protein (CREB) and PSD-95 in whole hippocampal tissue were significantly increased with AMK treatment. Before increasing in the whole tissue, CREB phosphorylation was significantly enhanced in the nuclear fraction. In the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, we found that downregulated genes in hippocampus of old C3H/He mice were more enriched for long-term potentiation (LTP) pathway. Gene set enrichment analysis showed that LTP and neuroactive receptor interaction gene sets were enriched in hippocampus of old mice. In addition, Ido1 and Tdo mRNA expression was significantly decreased in the hippocampus of old mice compared with young mice, and the decrease in Tdo mRNA was more pronounced than Ido1. Furthermore, there was a higher decrease in AMK levels, which was less than 1/10 that of young mice, than in melatonin levels in the hippocampus of old mice. In conclusion, we first demonstrated the Tdo-related melatonin to AMK metabolism in the hippocampus and suggest a novel mechanism of AMK involved in LTP and memory formation. These results support AMK as a potential therapeutic agent to prevent memory decline.

The potential beneficial effects of Lactobacillus plantarum GM11 on rats with chronic unpredictable mild stress- induced depression.

OBJECTIVE: The main purpose of the present study was to assess the beneficial effect of Lactobacillus plantarum GM11 (LacP GM11), screened from Sichuan traditional fermented food, in depressive rats induced by chronic unpredictable mild stress (CUMS). METHODS: Male SPF SD rats were randomly assigned to 3 groups: the control group, CUMS group and CUMS + LacP GM11 group (n = 10). The rats in the CUMS and LacP GM11 groups received CUMS stimulation for 42 d. The behavioral tests and levels of monoamine neurotransmitter, glucocorticoid hormone and brain-derived neurotrophic factor (BDNF) in the serum and hippocampus were measured. The effects of LacP GM11 on the mRNA and protein expression of BDNF and cAMP response element binding protein (CREB) in the hippocampus were also investigated. RESULTS: After supplementation for 21 d, LacP GM11 was associated with alleviation of depressive-like behavior, not anxiety-like behavior, in depressive rats. LacP GM11 increased the levels of 5-hydroxytryptamine (5-HT) and BDNF and decreased the level of cortisol (CORT) in the serum and hippocampus in depressed rats. In addition, treatment with LacP GM11 also increased the mRNA and protein expression of BDNF and CREB in the hippocampus. CONCLUSIONS: This work has revealed that LacP GM11 has potential beneficial effects on depression. This effect might be related to alleviating monoamine neurotransmitter deficiency, HPA axis hyperfunction and CREB-BDNF signaling pathway downregulation. This study demonstrates that LacP GM11 could be a potential therapeutic approach to treat depression and other mental health problems.

Particulate matter (PM10) exacerbates on MK-801-induced schizophrenia-like behaviors through the inhibition of ERK-CREB-BDNF signaling pathway.

Particulate matter (PM), released into the air by a variety of natural and human activities, is a key indicator of air pollution. Although PM is known as the extensive health hazard to affect a variety of illness, few studies have specifically investigated the effects of PM10 exposure on schizophrenic development. In the present study, we aimed to investigate the impact of PM10 on MK-801, N-methyl-D-aspartate (NMDA) receptor antagonist, induced schizophrenia-like behaviors in C57BL/6 mouse. Preadolescent mice were exposed PM10 to 3.2 mg/m3 concentration for 4 h/day for 2 weeks through a compartmentalized whole-body inhalation chamber. After PM10 exposure, we conducted behavioral tests during adolescence and adulthood to investigate longitudinal development of schizophrenia. We found that PM10 exacerbated schizophrenia-like behavior, such as psychomotor agitation, social interaction deficits and cognitive deficits at adulthood in MK-801-induced schizophrenia animal model. Furthermore, the reduced expression levels of brain-derived neurotrophic factor (BDNF) and the phosphorylation of BDNF related signaling molecules, extracellular signal-regulated kinase (ERK) and cAMP response element-binding protein (CREB), were exacerbated by PM10 exposure in the adult hippocampus of MK-801-treated mice. Thus, our present study demonstrates that exposure to PM10 in preadolescence exacerbates the cognitive impairment in animal model of schizophrenia, which are considered to be facilitated by the decreased level of BDNF through reduced ERK-CREB expression.

Investigating the Relevance of Cyclic Adenosine Monophosphate Response Element-Binding Protein to the Wound Healing Process: An In Vivo Study Using Photobiomodulation Treatment.

Monitoring inflammatory cytokines is crucial for assessing healing process and photobiomodulation (PBM) enhances wound healing. Meanwhile, cAMP response element-binding protein (CREB) is a regulator of cellular metabolism and proliferation. This study explored potential links between inflammatory cytokines and the activity of CREB in PBM-treated wounds. A total of 48 seven-week-old male SD rats were divided into four groups (wound location, skin or oral; treatment method, natural healing or PBM treatment). Wounds with a 6 mm diameter round shape were treated five times with an 808 nm laser every other day (total 60 J). The wound area was measured with a caliper and calculated using the elliptical formula. Histological analysis assessed the epidermal regeneration and collagen expression of skin and oral tissue with H&E and Masson's trichrome staining. Pro-inflammatory (TNF-α) and anti-inflammatory (TGF-ß) cytokines were quantified by RT-PCR. The ratio of phosphorylated CREB (p-CREB) to unphosphorylated CREB was identified through Western blot. PBM treatment significantly reduced the size of the wounds on day 3 and day 7, particularly in the skin wound group (p < 0.05 on day 3, p < 0.001 on day 7). The density of collagen expression was significantly higher in the PBM treatment group (in skin wound, p < 0.05 on day 3, p < 0.001 on day 7, and p < 0.05 on day 14; in oral wound, p < 0.01 on day 7). The TGF-ß/TNF-α ratio and the p-CREB/CREB ratio showed a parallel trend during wound healing. Our findings suggested that the CREB has potential as a meaningful marker to track the wound healing process.

Androgen receptor suppresses ß-adrenoceptor-mediated CREB activation and thermogenesis in brown adipose tissue of male mice.

Thermoregulation is a process by which core body temperature is maintained in mammals. Males typically have a lower body temperature than females. However, the effects of androgens, which show higher levels in males, on adrenergic receptor-mediated thermogenesis remain unclear. Here, we demonstrate that androgen-androgen receptor (AR) signaling suppresses the ß-adrenergic agonist-induced rise of core body temperature using castrated and AR knockout (ARKO) male mice. Furthermore, in vitro mechanistic studies show that activated AR inhibits cAMP response element (CRE)-mediated transcription by suppressing cAMP response element-binding protein (CREB) phosphorylation. The elevation of body temperature induced by the ß-adrenergic agonist CL316243 was higher in ARKO and castrated mice than in the control mice. Similarly, CL316243 induced a greater increase in Uncoupling protein 1 (Ucp1) expression and CREB phosphorylation in the brown adipose tissue of ARKO mice than in that of controls. We determined that activation of AR by dihydrotestosterone suppressed ß3-agonist- or forskolin-induced CRE-mediated transcription, which was prevented by AR antagonist. AR activation also suppressed CREB phosphorylation induced by forskolin. Moreover, we found AR nuclear localization, but not transcriptional activity, was necessary for the suppression of CRE-mediated transcription. Finally, modified mammalian two-hybrid and immunoprecipitation analyses suggest nuclear AR and CREB form a protein complex both in the presence and absence of dihydrotestosterone and forskolin. These results suggest androgen-AR signaling suppresses ß-adrenoceptor-induced UCP1-mediated brown adipose tissue thermogenesis by suppressing CREB phosphorylation, presumably owing to a protein complex with AR and CREB. This mechanism explains sexual differences in body temperature, at least partially.

Unleashing T cell anti-tumor immunity: new potential for 5-Nonloxytryptamine as an agent mediating MHC-I upregulation in tumors.

BACKGROUND: New therapies are urgently needed in melanoma, particularly in late-stage patients not responsive to immunotherapies and kinase inhibitors. To uncover novel potentiators of T cell anti-tumor immunity, we carried out an ex vivo pharmacological screen and identified 5-Nonyloxytryptamine (5-NL), a serotonin agonist, as increasing the ability of T cells to target tumor cells. METHODS: The pharmacological screen utilized lymphocytic choriomeningitis virus (LCMV)-primed splenic T cells and melanoma B16.F10 cells expressing the LCMV gp33 CTL epitope. In vivo tumor growth in C57BL/6 J and NSG mice, in vivo antibody depletion, flow cytometry, immunoblot, CRISPR/Cas9 knockout, histological and RNA-Seq analyses were used to decipher 5-NL's immunomodulatory effects in vitro and in vivo. RESULTS: 5-NL delayed tumor growth in vivo and the phenotype was dependent on the hosts' immune system, specifically CD8+ T cells. 5-NL's pro-immune effects were not directly consequential to T cells. Rather, 5-NL upregulated antigen presenting machinery in melanoma and other tumor cells in vitro and in vivo without increasing PD-L1 expression. Mechanistic studies indicated that 5-NL's induced MHC-I expression was inhibited by pharmacologically preventing cAMP Response Element-Binding Protein (CREB) phosphorylation. Importantly, 5-NL combined with anti-PD1 therapy showed significant improvement when compared to single anti-PD-1 treatment. CONCLUSIONS: This study demonstrates novel therapeutic opportunities for augmenting immune responses in poorly immunogenic tumors.

Dietary flavonoids-rich Citrus reticulata peel extract interacts with CREB signaling to suppress seizures and linked neurobehavioral impairments in a kindling mouse model.

Objectives: The citrus fruits peel contains a variety of bioactive metabolites that have shown multiple therapeutic effects. However, despite having substantial ethnomedicinal value, citrus peels remained underexplored and regarded as bio-waste. This present study was planned to investigate the effect of a characterized peel extract of Citrus reticulata c.v. (CRE) in pentylenetetrazole (PTZ)-induced kindling and associated cognitive and behavioral impairments in a mouse model.Methods: The kindled animals were treated daily with CRE (100 and 200 mg/kg) and challenged with a sub-effective dose of PTZ every 5th day to record the severity of seizures. In the end, different tests were performed to record behavioral and cognitive performance.Results: CRE-treated kindled animals showed a significant suppression in seizure severity following 20 days of the treatment. In the T-maze test, the extract treatment resulted in a marked increase in the spontaneous alternations, whereas it showed no change in anxiety behavior of kindled animals in the elevated plus-maze test. In both forced swim and tail suspension tests, CRE treatment demonstrated a considerable reduction in immobility time. However, no change in overall locomotion was observed in the open field test among all the groups. An increase in the hippocampal Creb and Bdnf expression and decreased glutamate-to-GABA ratio were observed in the CRE-treated kindled animals.Discussion: The results showed that CRE treatment suppresses epileptic seizures and associated cognitive deficits and depression-like behavior in kindled mice. The gene expression findings supported that the observed protective effects of CRE be due to its interaction with CREB signaling.

Puerarin alleviates depressive-like behaviors in high-fat diet-induced diabetic mice via modulating hippocampal GLP-1R/BDNF/TrkB signaling.

OBJECTIVE: Depression is one of the most common complications in patients with diabetes. Our previous study demonstrated puerarin, a dietary isoflavone, improved glucose homeostasis and ß-cell regeneration in high-fat diet (HFD)-induced diabetic mice. Here, we aim to evaluate the potential effect of puerarin on diabetes-induced depression. METHODS: The co-occurrence of diabetes and depression with related biochemical alterations were confirmed in HFD mice and db/db mice, respectively using behavioral analysis, ELISA and western blotting assay. Furthermore, impacts of puerarin on depression-related symptoms and pathological changes were investigated in HFD mice. RESULTS: The results showed that puerarin effectively alleviated the depression-like behaviors of HFD mice, down-regulated serum levels of corticosterone and IL-1ß, while up-regulated the content of 5-hydroxytryptamine. Simultaneously, puerarin increased the number of hippocampal neurons in HFD mice, and suppressed the apoptosis of neurons to protect the hippocampal neuroplasticity. GLP-1R expression in hippocampus of HFD mice was enhanced by puerarin, which subsequently activated AMPK, CREB and BDNF/TrkB signaling to improve neuroplasticity. Importantly, our data indicated that puerarin had an advantage over fluoxetine or metformin in treating diabetes-induced depression. CONCLUSION: Taken together, puerarin exerts anti-depressant-like effects on HFD diabetic mice, specifically by improving hippocampal neuroplasticity via GLP-1R/BDNF/TrkB signaling. Puerarin as a dietary supplement might be a potential candidate in intervention of diabetes with comorbid depression.

Correlation between variants of the CREB1 and GRM7 genes and risk of depression.

The pathogenesis of depression involves cAMP-response element binding protein1 (CREB1) and metabotropic glutamate receptor 7 (GRM7), and their genetic polymorphisms may affect susceptibility to depression. The purpose of this study was to investigate whether the CREB1 polymorphisms rs2253206 and rs10932201 and the GRM7 polymorphism rs162209 are associated with the risk of depression. Using polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing, we analyzed the rs2253206, rs10932201, and rs162209 frequencies in 479 patients with depression and 329 normal controls. The results showed that the rs2253206 and rs10932201 polymorphisms were significantly associated with an increased risk of depression. However, no association was found between rs162209 and depression risk. When the data were stratified for several disease-related variables, none of the three polymorphisms were found to be correlated to onset, disease severity, family history, or suicidal tendency. Thus, the present findings indicate that the CREB1 polymorphisms rs2253206 and rs10932201 may be related to the occurrence of depression.

Transcriptional and Histone Acetylation Changes Associated with CRE Elements Expose Key Factors Governing the Regulatory Circuit in the Early Stage of Huntington's Disease Models.

Huntington's disease (HD) is a disorder caused by an abnormal expansion of trinucleotide CAG repeats within the huntingtin (Htt) gene. Under normal conditions, the CREB Binding Protein interacts with CREB elements and acetylates Lysine 27 of Histone 3 to direct the expression of several genes. However, mutant Htt causes depletion of CBP, which in turn induces altered histone acetylation patterns and transcriptional deregulation. Here, we have studied a differential expression analysis and H3K27ac variation in 4- and 6-week-old R6/2 mice as a model of juvenile HD. The analysis of differential gene expression and acetylation levels were integrated into Gene Regulatory Networks revealing key regulators involved in the altered transcription cascade. Our results show changes in acetylation and gene expression levels that are related to impaired neuronal development, and key regulators clearly defined in 6-week-old mice are proposed to drive the downstream regulatory cascade in HD. Here, we describe the first approach to determine the relationship among epigenetic changes in the early stages of HD. We determined the existence of changes in pre-symptomatic stages of HD as a starting point for early onset indicators of the progression of this disease.

Phosphorylation of Neurofilament Light Chain in the VLO Is Correlated with Morphine-Induced Behavioral Sensitization in Rats.

Neurofilament light chain (NF-L) plays critical roles in synapses that are relevant to neuropsychiatric diseases. Despite postmortem evidence that NF-L is decreased in opiate abusers, its role and underlying mechanisms remain largely unknown. We found that the microinjection of the histone deacetylase (HDAC) inhibitor Trichostatin A (TSA) into the ventrolateral orbital cortex (VLO) attenuated chronic morphine-induced behavioral sensitization. The microinjection of TSA blocked the chronic morphine-induced decrease of NF-L. However, our chromatin immunoprecipitation (ChIP)-qPCR results indicated that this effect was not due to the acetylation of histone H3-Lysine 9 and 14 binding to the NF-L promotor. In line with the behavioral phenotype, the microinjection of TSA also blocked the chronic morphine-induced increase of p-ERK/p-CREB/p-NF-L. Finally, we compared chronic and acute morphine-induced behavioral sensitization. We found that although both chronic and acute morphine-induced behavioral sensitization were accompanied by an increase of p-CREB/p-NF-L, TSA exhibited opposing effects on behavioral phenotype and molecular changes at different addiction contexts. Thus, our findings revealed a novel role of NF-L in morphine-induced behavioral sensitization, and therefore provided some correlational evidence of the involvement of NF-L in opiate addiction.

Protective effects of the salt-induced kinase inhibitor HG-9-91-01 on sepsis-associated cognitive dysfunction in mice and the underlying mechanisms. / ç›è¯±å¯¼æ¿€é ¶æŠ‘åˆ¶å‰‚HG-9-91-01å¯¹å°é¼ è„“æ¯’ç—‡ç›¸å ³è®¤çŸ¥åŠŸèƒ½éšœç¢çš„ä¿æŠ¤ä½œç”¨åŠå ¶æœºåˆ¶.

OBJECTIVES: Sepsis-associated cognitive dysfunction is a common complication in patients with sepsis and lack of effective treatment. Its pathological mechanisms remain unclear. Salt-induced kinase (SIK) is an important molecule in the regulation of metabolism, immunity, and inflammatory response. It is associated with the development of many neurological diseases. This study aims to investigate the expression of SIK in the hippocampus of septic mice, and to evaluate the role and mechanism of the SIK inhibitor HG-9-91-01 in sepsis-associated cognitive dysfunction. METHODS: Firstly, C57BL/6 mice were randomly divided into a control group (Con group) and a sepsis model group [lipopolysaccharide (LPS) group]. The model group was injected intraperitoneally with LPS at a dose of 8 mg/kg and the Con group was injected with an equal volume of normal saline. Hippocampal tissues were harvested at 1, 3, and 6 days after injection and the expressions of SIK1, SIK2, and SIK3 were detected by real-time fluorescence quantitative PCR (qPCR) and Western blotting. Secondly, C57BL/6 mice were randomly divided into a Con group, a LPS group, and a SIK inhibitor group (HG group). The LPS and HG groups were injected with LPS to establish a sepsis model; in the HG group, HG-9-91-01 (10 mg/kg) was injected intraperitoneally at 3-6 days after LPS injection, and the LPS group was injected with the same volume of vehicle. Cognitive function was assessed at 7-11 days after LPS injection using the Morris water maze (MWM). Hippocampal tissues were harvested after the behavioral tests, and the mRNA levels of inflammatory factors and microglial markers were assessed by qPCR. The protein levels of inducible nitric oxide synthase (iNOS), CD68, ionized calcium binding adaptor molecule 1 (Iba-1), N-methyl-D-aspartate (NMDA) receptor (NR) subunit, cAMP response element-binding protein (CREB)-regulated transcription coactivator 1 (CRTC1), and insulin-like growth factor 1 (IGF-1) were detected by Western blotting. Immunohistochemistry (IHC) was used to detect the expression of Iba-1 positive cells in the CA1, CA3 and dentate gyrus (DG) of the hippocampus, followed by Sholl analysis. RESULTS: Compared with the Con group, the mRNA and protein levels of SIK1, SIK2, and SIK3 in the hippocampus were increased in the LPS group (all P<0.05). Compared with the Con group, mice in the LPS group had a significantly longer escape latency, a lower percentage of target quadrant dwell time and a reduced locomotor speed (all P<0.05); the HG group had a decreased escape latency and an increased percentage of time spent in the target quadrant in comparison with the LPS group (both P<0.05). The mRNA levels of inflammatory factors [tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6)], and the M1-type microglial markers iNOS and CD68 in the hippocampus of the LPS group were increased in comparison with the Con group, while the M2-type microglial markers CD206 and arginase-1 (Arg-1) were decreased. Compared with the LPS group, the mRNA levels of TNF-α, IL-1ß, IL-6, and iNOS were downregulated, while the levels of CD206 and Arg-1 were upregulated in the HG group (all P<0.05). The protein levels of iNOS, CD68, and Iba-1 in the hippocampus of the LPS group were increased in comparison with the Con group, but they were downregulated in the HG group in comparison with the LPS group (all P<0.05). The number of Iba-1 positive cells in CA1, CA3, and DG of the hippocampus was increased in the LPS group in comparison with the Con group, but they were decreased in the HG group in comparison with the LPS group (all P<0.05). Sholl analysis showed that the number of intersections at all radii between 8-38 µm from the microglial soma was decreased in the LPS group in comparison with the Con group (all P<0.05). Compared with the LPS group, the number of intersections at all radii between 14-20 µm was significantly increased in the HG group (all P<0.05). The protein levels of NR subunit NR1, NR2A, NR2B, and IGF-1 were downregulated in the hippocampus of the LPS group in comparison with the Con group, while the expression of phosphorylated CRTC1 (p-CRTC1) was increased. Compared with the LPS group, the levels of NR1, NR2A, NR2B, and IGF-1 were upregulated, while p-CRTC1 was downregulated in the HG group (all P<0.05). CONCLUSIONS: SIK expression is upregulated in the hippocampus of septic mice. The SIK inhibitor HG-9-91-01 ameliorates sepsis-associated cognitive dysfunction in mice, and the mechanism may involve in the activation of the CRTC1/IGF-1 pathway, inhibition of neuroinflammation, and enhancement of synaptic plasticity.

Hyperhomocysteinemia Induces Rat Memory Impairment Via Injuring Hippocampal CA3 Neurons and Downregulating cAMP Response Element-Binding Protein (CREB) Phosphorylation.

Accumulated evidence demonstrated that an elevated plasma homocysteine level, hyperhomocysteinemia, induced cognitive impairment in animals, elderly and the patients with neurodegenerative diseases. To date, the underlying cellular and molecular mechanisms by which hyperhomocysteinemia induces cognitive impairment has not been clearly defined. The purpose of this study was to investigate the possible cellular and molecular mechanisms behind hyperhomocysteinemia signaling in rat memory impairment. The results from this study demonstrated that hyperhomocysteinemia induced neuronal damage and loss in hippocampal CA3 region and downregulated the cAMP response element-binding protein (CREB) phosphorylation. The findings of this study provide evidence that hyperhomocysteinemia induces rat memory impairment via injuring hippocampal CA3 neurons and downregulating CREB phosphorylation.

Neuroprotective Effect of Piclamilast-Induced Post-Ischemia Pharmacological Treatment in Mice.

Various studies have evidenced the neuroprotective role of PDE4 inhibitors. However, whether PDE4 inhibitor, Piclamilast pharmacological post-treatment is protective during cerebral ischemia reperfusion-induced injury remains unknown. Therefore, this study design included testing the hypothesis that Piclamilast administered at the beginning of a reperfusion phase (Piclamilast pPost-trt) shows protective effects and explores & probes underlying downstream mechanisms. Swiss albino male mice were subjected to global ischemic and reperfusion injury for 17 min. The animals examined cerebral infarct size, biochemical parameters, inflammatory mediators, and motor coordination. For memory, assessment mice were subjected to morris water maze (MWM) and elevated plus maze (EPM) test. Histological changes were assessed using HE staining. Piclamilast pPost-trt significantly reduced I/R injury-induced deleterious effects on biochemical parameters of oxidative stress, inflammatory parameters, infarct size, and histopathological changes, according to the findings. These neuroprotective effects of pPost-trt are significantly abolished by pre-treatment with selective CREB inhibitor, 666-15. Current study concluded that induced neuroprotective benefits of Piclamilast Post-trt, in all probability, maybe mediated through CREB activation. Hence, its neuroprotective effects can be further explored in clinical settings.

Salt-inducible kinase 2 (SIK2) inhibitor ARN-3236 attenuates bleomycin-induced pulmonary fibrosis in mice.

BACKGROUND: Pulmonary fibrosis is a fatal lung disease with complex pathogenesis and limited effective therapies. Salt-inducible kinase 2 (SIK2) is a kinase that phosphorylates CRTCs and regulates many physiological processes. However, the role of SIK2 on pulmonary fibrosis remains unclear, and whether SIK2 inhibitor can attenuate pulmonary fibrosis is unknown. METHOD: We subjected human fetal lung fibroblasts (HFLs) to transforming growth factor-ß1 (5 ng/mL) for 12 h, and examined the expression of SIK2, CRTCs and pCRTCs in fibroblasts by western-blot. To address the roles of SIK2 and CRTCs involved in the progression of pulmonary fibrosis, HFLs were treated with a small-molecule inhibitor ARN-3236 or by siRNA-mediated knockdown of SIK2 expression. Pulmonary fibrosis model was established with mice by exposing to bleomycin, and assessed by H&E and Masson's trichrome staining. COL1A and α-SMA distributions were detected in lung tissues by immunohistochemical staining. RESULTS: We discovered that SIK2 and phosphorylated-CRTC2 were expressed at a low basal level in normal lung tissues and quiescent fibroblasts, but increased in fibrotic lung tissues and activated fibroblasts. Inhibition of SIK2 by ARN-3236 prevented the fibroblasts differentiation and extracellular matrix expression in HFLs and attenuated bleomycin-induced pulmonary fibrosis in mice. Mechanistically, inactivation of SIK2 resulted in the dephosphorylation and nuclear translocation of CRTC2. Within the nucleus, CRTC2 binds to CREB, promoting CREB-dependent anti-fibrotic actions. CONCLUSION: In conclusion, our results elucidated a previously unexplored role of SIK2 in pulmonary fibrosis, and identified SIK2 as a new target for anti-fibrosis medicines.

Telocytes reduce oxidative stress by downregulating DUOX2 expression in inflamed lungs of mice.

Telocytes (TCs), a novel type of interstitial cells, have been found to participate in tissue protection and repair. In this study, we investigated the antioxidative effects of TCs in inflamed lungs of mice. Acute respiratory distress syndrome (ARDS) mice were used as models of inflamed lungs of mice. Gene sequencing was used to screen the differentially expressed miRNAs in TCs after lipopolysaccharide (LPS) stimulation. AntagomiR-146a-5p-pretreated TCs were first injected into mice, and antioxidant activity of TCs was estimated. TCs, RAW264.7 cells, and MLE-12 cells were collected for the detection of expressions of NOX1-4, DUOX1-2, SOD1-3, GPX1-2, CAT, Nrf2, miR-146a-5p, and miR-21a-3p after LPS stimulation. Silencing miRNAs were delivered to examine the involved signaling pathways. Oxidative stress was examined by measuring malondialdehyde (MDA) levels. We found that microRNA-146a-5p and microRNA-21a-3p were upregulated in TCs after LPS stimulation. ARDS mice that were preinfused with TCs had lower lung tissue injury scores, lung wet-dry ratios, white blood cell counts in alveolar lavage fluid and lower MDA concentrations in lung tissue. However, in antagomiR-146a-5p-pretreated ARDS mice, the infusion of TCs caused no corresponding changes. After LPS stimulation, DUOX2 and MDA concentrations were downregulated in TCs, while DUOX2 was restored by antagomiR-146a-5p in TCs. Dual-luciferase reporter assay confirmed that CREB1 was downregulated by miR-146a-5p, while DUOX2 was downregulated by CREB1, which was confirmed by treating TCs with a specific CREB1 inhibitor. This study demonstrates that LPS stimulation upregulates miR-146a-5p in TCs, which downregulates the CREB1/DUOX2 pathway, resulting in a decrease in oxidative stress in cultured TCs. TCs reduce LPS-induced oxidative stress by decreasing DUOX2 in inflamed lungs of mice.

Cell-Free Supernatant from Lactobacillus and Streptococcus Strains Modulate Mucus Production via Nf-κB/CREB Pathway in Diesel Particle Matter-Stimulated NCI-H292 Airway Epithelial Cells.

Airway epithelial cells are a major site of airway inflammation and may play an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Diesel particulate matter (DPM) is associated with mucus hypersecretion and airway inflammation and has been reported to overexpress airway mucin in the NCI-H292 airway epithelial cells. Therefore, regulation of mucin hypersecretion is essential for developing novel anti-inflammatory agents. This study aimed to investigate the effects of cell-free supernatant (CFS) from Lactobacillus and Streptococcus on nitro oxide (NO) production in RAW264.7 and proteins associated with mucus production in NCI-H292 cells. We observed that NO production was reduced by CFS from Lactobacillus and Streptococcus in RAW 264.7, and MUC4, MUC5AC, and MUC5B gene expression was increased by phosphorylation of nuclear factor kappa B (NF-κB) p65 and cAMP response element-binding protein (CREB) in DPM-stimulated NCI-H292 cells. However, CFS from L. paracasei MG4272, MG4577, L. gasseri MG4247, and S. thermophilus MG5140 inhibited mRNA expression related to mucus production by downregulating the CREB/NfκB signaling pathway. These results suggest that CFS from L. paracasei MG4272, MG4577, L. gasseri MG4247, and S. thermophilus MG5140 can contribute as a strategic candidate to the prevention of airway inflammatory diseases caused by DPM.

EphB2 activates CREB-dependent expression of Annexin A1 to regulate dendritic spine morphogenesis.

Dendritic spines are the postsynaptic structure to mediate signal transduction in neural circuitry, whose function and plasticity are regulated by organization of their molecular architecture and by the expression of target genes and proteins. EphB2, a member of the Eph receptor tyrosine kinase family, potentiates dendritic spine maturation through cytoskeleton reorganization and protein trafficking. However, the transcriptional mechanisms underlying prolonged activation of EphB2 signaling during dendritic spine morphogenesis are unknown. Herein, we performed transcriptional profiling by stimulating EphB2 signaling and identified differentially expressed genes implicated in pivotal roles at synapses. Notably, we characterized an F-actin binding protein, Annexin A1, whose expression was induced by EphB2 signaling; the promotor activity of its coding gene Anxa1 is regulated by the activity of CREB (cAMP-response element-binding protein). Knockdown of Annexin A1 led to a significant reduction of mature dendritic spines without an obvious deficit in the complexity of dendrites. Altogether, our findings suggest that EphB2-induced, CREB-dependent Annexin A1 expression plays a key role in regulating dendritic spine morphology.