S100A4/NF-κB axis mediates the anticancer effect of epigallocatechin-3-gallate in platinum-resistant ovarian cancer.

Resistance to cisplatin (cis-dichlorodiamineplatinum, DDP) in ovarian cancer is a significant clinical challenge. Epigallocatechin-3-gallate (EGCG) has shown promise in cancer therapy. However, its effects on DDP-resistant ovarian cancer remain understudied. This study aims to assess the impact of EGCG on DDP-resistant cells and elucidate the associated molecular mechanisms. DDP-resistant cell lines were utilized for biological characterization. EGCG effectively inhibited proliferation, mobility, and induced apoptosis in OC/DDP cells. It downregulated the expression of S100A4 and NF-κB while upregulating p53 expression. These effects were reversed upon overexpression of S100A4 or NF-κB. In vivo experiments confirmed tumor inhibition and KI67 inhibition by EGCG. Moreover, EGCG downregulated the expression of S100A4 and NF-κB while upregulating p53 in xenograft mice compared to those without EGCG treatment. This study suggests that EGCG suppresses cancer progression through the S100A4/NF-κB signaling pathway, involving interaction with p53. EGCG holds potential as an anticancer candidate for OC/DDP.

Study on the postoperative visual function recovery of children with concomitant exotropia based on an augmented reality plasticity model.

Objective: This study aimed to investigate the clinical application effect of an augmented reality (AR) plasticity model on the postoperative visual function recovery of children with concomitant exotropia. Methods: Between September 2019 and October 2021, 28 patients with concomitant exotropia who visited Shenzhen Children's Hospital (9 male and 19 female) were enrolled in this study. The average age of the patients was 6.4 ± 1.8 years. Postoperative rehabilitation training was conducted using a personalized AR binocular visual perception plasticity model developed based on the patient's examination results. After 1 month, 3 months, and 6 months of training, the patients returned to the hospital for examinations of perceptual eye position, static zero-order stereopsis, dynamic first-order fine stereopsis, and dynamic second-order coarse stereopsis to compare the changes in eye position control and stereovision function. Results: After 6 months of eye position training, the horizontal perception eye position of the 28 patients was significantly lower than that before training. The difference in eye position at the first and third months compared with that before training was not statistically significant (1st month: z = -2.255, p = 0.024 > 0.017; 3rd month: z = -2.277, p = 0.023 > 0.017; 6th month: z = -3.051, p = 0.002 < 0.017). The difference in vertical perceptual eye position after training compared with that before training was not statistically significant (1st month: z = -0.252, p = 0.801 > 0.017; 3rd month: z = -1.189, p = 0.234 > 0.017; 6th month: z = -2.225, p = 0.026 > 0.017). The difference in 0.8-m static zero-order stereopsis before and after training was not statistically significant (1st month: z = -2.111, p = 0.035 > 0.017; 3rd month: z = -1.097, p = 0.273 > 0.017; 6th month: z = -1.653, p = 0.098 > 0.017). The 1.5-m static zero-order stereopsis was improved after 1 month, 3 months, and 6 months of training compared with that before training (1st month: z = -3.134, p = 0.002 < 0.017; 3rd month: z = -2.835, p = 0.005 < 0.017; 6th month: z = -3.096, p = 0.002 < 0.017). Dynamic first-order fine stereopsis and dynamic second-order coarse stereopsis were measured in the 28 patients before and after training. Patients 1 and 18 had no dynamic first-order fine stereopsis before training, but both regained dynamic stereopsis after 1 month, 3 months, and 6 months of training. Patient 16 had no dynamic first-order fine stereopsis or dynamic second-order coarse stereopsis before training, but first-order and second-order stereopsis had been reconstructed after 1 month, 3 months, and 6 months of training. Conclusion: Concomitant exotropia surgery improved the basic problem of eye position at the ocular muscle level, but the patient's perceptual eye position and visual function defects at the brain visual level remained. This might partly explain the poor postoperative clinical effect. The AR plasticity model can improve patients' horizontal perceptual eye position and multi-dimensional stereoscopic function, and its clinical effect warrants further study.

Osthole exhibits an antitumor effect in retinoblastoma through inhibiting the PI3K/AKT/mTOR pathway via regulating the hsa_circ_0007534/miR-214-3p axis.

CONTEXT: Osthole shows antitumor effects in various tumours. Studies describing the effect of osthole on retinoblastoma (RB) are rare. OBJECTIVE: This study investigates the antitumor activity of osthole on RB. MATERIALS AND METHODS: RB cells were treated with different concentrations of osthole and then subjected to cell viability, colony formation, apoptosis, and western blot assays. The expression of hsa_circ_0007534 in RB tissues was determined by qRT-PCR. Hsa_circ_0007534 overexpression plasmid (oe-circ_0007534), miR-214-3p mimics and negative controls were transfected into RB cells to investigate cell viability. Athymic nude mice were injected with Y-79 cells to establish subcutaneous RB models. These mice were treated with osthole (0.5 mmol/kg) or corn oil for 36 days. Tumour tissues were collected for further analysis. RESULTS: Osthole inhibited cell viability of RB cells with an IC50 of 200 µM for 24 h treatment and 120 µM for 48 h treatment, respectively. Hsa_circ_0007534 was increased significantly in RB tissues as compared to the matched nontumor tissues (p < 0.001). Oe-circ_0007534 counteracted the inhibitory effect of osthole on cell viability and colony numbers of Y-79 cells (p < 0.01). In vivo experiments indicated osthole significantly decreased the expression of hsa_circ_0007534 (p < 0.01) and increased the level of miR-214-3p in vivo. Furthermore, as compared to the control, osthole decreased the ratios of p-PI3K/PI3K, p-AKT/AKT and p-mTOR/mTOR (p < 0.01). However, hsa_circ_0007534 overexpression reversed the effect of osthole on the PI3K/AKT/mTOR pathway. DISCUSSION AND CONCLUSIONS: Osthole exhibited an antitumour effect in RB, providing a scientific basis for further research and clinical applications of osthole in RB treatment.

Liver injury changes the biological characters of serum small extracellular vesicles and reprograms hepatic macrophages in mice.

BACKGROUND: Serum small extracellular vesicles (sEVs) and their small RNA (sRNA) cargoes could be promising biomarkers for the diagnosis of liver injury. However, the dynamic changes in serum sEVs and their sRNA components during liver injury have not been well characterized. Given that hepatic macrophages can quickly clear intravenously injected sEVs, the effect of liver injury-related serum sEVs on hepatic macrophages deserves to be explored. AIM: To identify the characteristics of serum sEVs and the sRNAs during liver injury and explore their effects on hepatic macrophages. METHODS: To identify serum sEV biomarkers for liver injury, we established a CCL4-induced mouse liver injury model in C57BL/6 mice to simulate acute liver injury (ALI), chronic liver injury (CLI) and recovery. Serum sEVs were obtained and characterized by transmission electron microscopy and nanoparticle tracking analysis. Serum sEV sRNAs were profiled by sRNA sequencing. Differentially expressed microRNAs (miRNAs) were compared to mouse liver-enriched miRNAs and previously reported circulating miRNAs related to human liver diseases. The biological significance was evaluated by Ingenuity Pathway Analysis of altered sEV miRNAs and conditioned cultures of ALI serum sEVs with primary hepatic macrophages. RESULTS: We found that both ALI and CLI changed the concentration and morphology of serum sEVs. The proportion of serum sEV miRNAs increased upon liver injury, with the liver as the primary contributor. The altered serum sEV miRNAs based on mouse studies were consistent with human liver disease-related circulating miRNAs. We established serum sEV miRNA signatures for ALI and CLI and a panel of miRNAs (miR-122-5p, miR-192-5p, and miR-22-3p) as a common marker for liver injury. The differential serum sEV miRNAs in ALI contributed mainly to liver steatosis and inflammation, while those in CLI contributed primarily to hepatocellular carcinoma and hyperplasia. ALI serum sEVs decreased both CD86 and CD206 expression in monocyte-derived macrophages but increased CD206 expression in resident macrophages in vitro. CONCLUSION: Serum sEVs acquired different concentrations, sizes, morphologies and sRNA contents upon liver injury and could change the phenotype of liver macrophages. Serum sEVs therefore have good diagnostic and therapeutic potential for liver injury.

SSR2 overexpression associates with tumorigenesis and metastasis of Hepatocellular Carcinoma through modulating EMT.

Background: Hepatocellular carcinoma (HCC) is a common malignancy around the world. The molecular mechanisms underlying HCC tumorigenesis and metastasis are far from clear. Numerous studies have pointed out that signal sequence receptor (SSR) is an endoplasmic reticulum-related protein involved in protein folding and processing of eukaryotic cells. SSR2 is a subunit of SSR protein, but the role of SSR2 in hepatocellular carcinoma is largely unknown and warrants further study. Materials and Methods: Several public databases were data mined to analyze the expression of four subunits of SSR between tumor and its peritumor counterparts. Also, the expression of SSR2 in our own collected tissues from HCC patients were analyzed by IHC and quantitative PCR. Survival analyses were conducted to delineate the prognostic value of SSR2. Clinical data were obtained followed by analysis based on SSR2 expression. Afterwards, cell proliferation, migration and invasion were detected by IncuCyte and trans-well assays, respectively. RNA interference was carried out by transfecting specific siRNA targeting SSR2 into cells using lipo2000. Western blot was applied to validate the knockdown effect and regulation on EMT-related proteins. Results: We examined the expression of SSR and its correlation with recurrence and survival of patients. We discovered that SSR2 overexpression was negatively associated with survival of HCC patients from TCGA databases and the mutation of SSR2 was most among the four subunits of SSR protein. Additionally, in this study, we collected tumor and adjacent tissues from 125 cases of HCC patients. Through constructing tissue microarray, we have identified that SSR2 was highly expressed in HCC tumor tissues compared with adjacent normal tissues of hepatocellular carcinoma patients by immunohistochemistry assays. Furthermore, Kaplan-Meier survival analysis from our collected tissues revealed that the overexpression of SSR2 was inversely correlated with disease free survival and overall survival of HCC patients. We elucidated that SSR2 promotes proliferation, migration and invasion of HCC cells. SSR2 knockdown suppressed epithelial mesenchymal transition (EMT) of HCC cells. Conclusions: These results collectively show that SSR2 is overexpressed in HCC tumor tissues, and it is an important factor in predicting survival of HCC patients. Additionally, it is involved in metastasis of HCC. These findings may help to exploit SSR2 as a novel factor in predicting prognosis and metastasis of HCC.

SRXN1 stimulates hepatocellular carcinoma tumorigenesis and metastasis through modulating ROS/p65/BTG2 signalling.

Sulfiredoxin 1 (SRXN1) is a pivotal regulator of the antioxidant response in eukaryotic cells. However, the role of SRXN1 in hepatocellular carcinoma (HCC) is far from clear. The present study aims to elucidate whether SRXN1 participates in tumorigenesis and metastasis of HCC and to determine the molecular mechanisms. We found that SRXN1 expression was up-regulated in HCC tissue samples and correlated with poor prognosis in HCC patients. We also observed that SRXN1 knockdown by transient siRNA transfection inhibited HCC cell proliferation, migration and invasion. Overexpression of SRXN1 increased HCC cell migration and invasion. B-cell translocation gene 2 (BTG2) was identified as a downstream target of SRXN1. Mechanistic studies revealed that SRXN1-depleted reactive oxygen species (ROS) modulated migration and invasion of HCC cells. In addition, the ROS/p65/BTG2 signalling hub was found to regulate the epithelial-mesenchymal transition (EMT), which mediates the pro-metastasis role of SRXN1 in HCC cells. In vivo experiments showed SRXN1 promotes HCC tumour growth and metastasis in mouse subcutaneous xenograft and metastasis models. Collectively, our results revealed a novel pro-tumorigenic and pro-metastatic function of SRXN1 in HCC. These findings demonstrate a rationale to exploit SRXN1 as a therapeutic target effectively preventing metastasis of HCC.

Characterization of serum small extracellular vesicles and their small RNA contents across humans, rats, and mice.

Serum small extracellular vesicles (sEVs) have recently drawn considerable interest because of the diagnostic and therapeutic potential of their miRNAs content. However, the characteristics of human, mouse and rat serum sEVs and their differences in small RNA contents are still unknown. In this study, through nanoparticle tracking analysis and small RNA sequencing, we found that human, rat, and mouse serum sEVs exhibited distinct sizes and particle numbers as well as small RNA contents. Serum sEVs contained not only abundant miRNAs but also a large number of tRNA fragments. Most serum miRNAs existed both inside and outside of sEVs but were enriched in sEVs. Common serum sEV miRNAs (188 miRNAs) and species-specific serum sEV miRNAs (265, 58, and 159 miRNAs, respectively) were identified in humans, rats, or mice. The serum sEVs contained miRNAs from tissues and organs throughout the body, with blood cells as the main contributors. In conclusion, our findings confirmed the rationality of exploring serum sEV miRNAs as noninvasive diagnostic markers and revealed great differences in serum sEV small RNAs between humans, rats, and mice. Inadequate attention to these differences and the contribution of blood cells to serum sEV miRNAs could hinder the clinical translation of basic studies.

Expression of neuropeptide Y is increased in an activated human HSC cell line.

Neuropeptide Y (NPY) is an abundant neuropeptide in the mammalian central and peripheral nervous systems. Transgenic mice overexpressing NPY in noradrenergic neurons have increased level of hepatic triglycerides, fatty acids and cholesterol, which contributed to the development of hepatosteatosis. However, the roles of NPY in the activation of hepatic stellate cells (HSCs) and the underlying mechanisms remain unclear. This study aimed to investigate the expression and secretion of NPY in human immortalized HSC LX-2 cells and the regulatory function of NPY on the fibrogenic response in LX-2 cells, to explore the potential association between NPY and LX-2 activation. The results showed an increase in the expression and secretion of NPY(1-36) in activated LX-2 cells. Both endogenous and exogenous NPY(1-36) induced the phosphorylation of mTOR, p70S6K, and 4EBP1 and promoted the fibrogenic response via NPY Y1 receptor subtype (NPY1R), as these responses were blocked by either an NPY1R antagonist (BIBP3226) or NPY1R knockdown. Moreover, NPY(1-36) serum levels were increased in patients with liver cirrhosis (LC) and hepatocellular carcinoma (HCC) and presented a positive relationship with MELD scores in LC patients. These findings suggest that immortalized HSCs LX-2 have the potential to produce NPY(1-36). High serum levels of NPY(1-36) is correlated with hepatic dysfunction in cirrhotic patients.

Long-term systemic administration with low dose of 3,4-methylenedioxymethamphetamine causes photoreceptor cell damage in CD1 mice.

OBJECTIVE: As a powerful psychostimulant with high potential for abuse, 3,4-methylenedioxymethamphetamine (MDMA) causes long-lasting neurotoxicity. This study was to investigate the effects of systemic administration of MDMA on retinal damage in CD1 mice and its underlying mechanisms. MATERIAL AND METHODS: CD1 mice were randomly divided into two groups (n = 10): group 1 receiving PBS by intraperitoneal injection daily; group 2 receiving 2 mg/kg MDMA by intraperitoneal injection daily for 3 months. The retinal function was tested by electroretinography (ERG). The retinal morphology and histology was evaluated by Toluidine blue staining and TUNEL assay, respectively. Inflammatory cytokines were measured by ELISA assays. Gene and protein expression was detected by real-time PCR and western blot. RESULTS: Results demonstrated that retinal damage was caused by MDMA after 3-month treatment, evidenced by retinal dysfunction through photoreceptor cell apoptosis induced by inflammatory response and oxidative stress. CONCLUSION: Our study indicated that systemic administration of MDMA increased inflammatory response in photoreceptor cells to cause retinal dysfunction on CD1 mice, providing the scientific rationale for the photoreceptor cell damage caused by the MDMA abuse.

Downregulation of Nedd4L predicts poor prognosis, promotes tumor growth and inhibits MAPK/ERK signal pathway in hepatocellular carcinoma.

Accumulating evidence indicates that the neural precursor cell-expressed, developmentally downregulated 4-like (Nedd4L) related with some tumor progression pathways and was found abnormally expressed in several kinds of solid cancers. However, the role and mechanism of Nedd4L in HCC remain unknown. This study was to assess the role of Nedd4L in HCC tumorigenesis and prognosis. The real-time quantitative RT-PCR and immunohistochemistry results revealed that Nedd4L was downregulated in HCC tissues compared to corresponding peri-noncancerous tissue, and HCC patients with low expression of Nedd4L exhibited poor prognosis assessed by Kaplan-Meier and Cox regression analysis in 78 HCC patients. Furthermore, knockdown of Nedd4L could significantly promote proliferation of HCC cells by CCK-8 and colony formation assays in vitro; whereas ectopic expression of Nedd4L resulted in attenuating proliferation in vitro and tumor growth in vivc determined by nude mice xenografts model. Mechanically, Nedd4L could phosphorylate ERK1/2 and regulate genes related with apoptosis. Collectively, Nedd4L plays a tumor suppressive role in HCC, possibly through triggering MAPK/ERK-mediated apoptosis, and Nedd4L downregulation may be a potential prognostic biomarker as well as a therapeutic target for HCC.

Neuropeptide Y1 receptor inhibits cell growth through inactivating mitogen-activated protein kinase signal pathway in human hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most common cancers, and its incidence is increasing worldwide. Neuropeptide Y (NPY) broadly expressed in the central and peripheral nervous system. It participates in multiple physiological and pathological processes through specific receptors. Evidences are accumulating that NPY is involved in development and progression in neuro- or endocrine-related cancers. However, little is known about the potential roles and underlying mechanisms of NPY receptors in HCC. In this study, we analyzed the expression of NPY receptors by real-time polymerase chain reaction, Western blot, and immunohistochemical staining. Correlation between NPY1R levels and clinicopathological characteristics, and survival of HCC patients were explored, respectively. Cell proliferation was researched by CCK-8 in vitro, and tumor growth was studied by nude mice xenografts in vivo. We found that mRNA and protein level of NPY receptor Y1 subtype (NPY1R) significantly decreased in HCC tissues. Low expression of NPY1R closely correlated with poor prognosis in HCC patients. Proliferation of HCC cells was significantly inhibited by recombinant NPY protein in vitro. This inhibitory effect could be blocked by selected NPY1R antagonist BIBP3226. Furthermore, overexpression of NPY1R could significantly inhibit HCC cell proliferation. Knockdown of NPY1R promoted cell multiplication in vitro and increased tumorigenicity and tumor growth in vivo. NPY1R was found to participate in the inhibition of cell proliferation via inactivating mitogen-activated protein kinase signal pathway in HCC cells. Collectively, NPY1R plays an inhibitory role in tumor growth and may be a promising therapeutic target for HCC.

NAc Shell Arc/Arg3.1 Protein Mediates Reconsolidation of Morphine CPP by Increased GluR1 Cell Surface Expression: Activation of ERK-Coupled CREB is Required.

BACKGROUND: Relapse into drug abuse evoked by reexposure to the drug-associated context has been a primary problem in the treatment of drug addiction. Disrupting the reconsolidation of drug-related context memory would therefore limit the relapse susceptibility. METHODS: Morphine conditioned place preference (CPP) was used to assess activity-regulated cytoskeleton-associated protein (Arc/Arg3.1) and correlative molecule expression in the Nucleus accumbens (NAc) shell during the reconsolidation of morphine CPP. U0126 and Arc/Arg3.1 antisense oligodeoxynucleotide were adapted to evaluate the role and the underlying mechanism of Arc/Arg3.1 during the reconsolidation. RESULTS: The retrieval of morphine CPP in rats specifically increased the Arc/Arg3.1 protein level in the NAc shell, accompanied simultaneously by increases in the phosphorylation of extracellular signal-regulated kinase1/2 (pERK1/2), the phosphorylation of Cyclic Adenosine monophosphate (cAMP) response element-binding (pCREB), and the up-regulation of the membrane α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors GluR1 subunit level. Intra-NAc shell infusion U0126, an inhibitor of the Mitogen-activated protein kinase kinase (MEK), prevented the retrieval-induced up-regulation of pERK1/2, pCREB, Arc/Arg3.1, and membrane GluR1 immediately after retrieval of morphine CPP. The effect of disrupting the reconsolidation of morphine CPP by U0126 could last for at least 14 days, and could not be evoked by a priming injection of morphine. Furthermore, the specific knockdown of Arc/Arg3.1 in the NAc shell decreased the membrane GluR1 level, and impaired both the reconsolidation and the reinstatement of morphine CPP. CONCLUSIONS: Arc/Arg3.1 in the NAc shell mediates the reconsolidation of morphine-associated context memory via up-regulating the level of membrane of GluR1, for which the local activation of the ERK-CREB signal pathway, as an upstream mechanism of Arc/Arg3.1, is required.

Diagnostic values of alpha-fetoprotein, dickkopf-1, and osteopontin for hepatocellular carcinoma.

The timely diagnosis and effective treatment are essential for improving the survival and prognosis of hepatocellular carcinoma (HCC) patients. Alpha-fetoprotein (AFP) is the most widely used biomarker for diagnosis of HCC, but the low sensitivity and specificity limits its clinical application. In this study, we evaluated the diagnostic capability of the combination of AFP with two novel potential biomarkers, dickkopf-1 (DKK1) and osteopontin (OPN), for HCC in 390 participants including 89 patients with HCC, 36 patients with liver cirrhosis, 65 patients with chronic hepatitis B, and 200 health controls. We found the combination of all three markers as a panel showed a better diagnostic performance than that of AFP alone, with increased AUC [0.948 (95% CI 0.921-0.968) vs. 0.831 (95% CI 0.790-0.867)] and sensitivity (88.76 vs. 71.91%). Moreover, this combination showed a great improvement in diagnosing early-stage HCC patients. In conclusion, the combined use of AFP, DKK1, and OPN as a biomarker panel could enhance the diagnostic ability for HCC.

Overexpression of Dickkopf-1 predicts poor prognosis for patients with hepatocellular carcinoma after orthotopic liver transplantation by promoting cancer metastasis and recurrence.

Our previous data had shown that Dickkopf-1 (DKK1) combined with ß-catenin was a novel prognostic predictor for hepatocellular carcinoma (HCC) patients. However, the role and mechanism of DKK1 in HCC recurrence or metastasis remain poorly understand. This study was to assess the role of DKK1 in tumor metastasis for patients with hepatocellular carcinoma after orthotopic liver transplantation (OLT). The expression of DKK1 protein was detected in hepatic cell lines, HCC cell lines, and HCC patients after OLT with different potential of metastasis. After DKK1 expression in the HCCLM3 cells was downregulated by siRNA-mediated approach, the role of DKK1 in cell invasion and metastasis was investigated. cDNA genechip was used to analyze the differential expressed genes related with DKK1 in two pairs of HCC cells. The prognostic significance of DKK1 was further assessed by Kaplan-Meier and Cox regression analyses in 148 HCC patients after OLT. The expression of DKK1 protein was higher in the high-invasive HCC cells and HCC patients of the disease recurrence group. With the downregulation of DKK1, HCCLM3 cells showed decreased aggressiveness in vitro and lower metastatic ability in vivo. DKK1 could regulate many genes involved in biological processes and pathways related with tumor progression. Furthermore, DKK1 overexpression correlated with tumor microvessel density in clinical HCC samples. Multivariate analysis revealed that DKK1 was an independent prognostic indicator for overall survival and cumulative recurrence in this cohort of HCC patients post-OLT. Collectively, overexpression of DKK1 was implicated in invasion/metastasis of HCC after OLT and DKK1 overexpression may be potential molecular therapeutic targets for liver cancer.

Essential role of NR2B-containing NMDA receptor-ERK pathway in nucleus accumbens shell in morphine-associated contextual memory.

Learned associations between the rewarding effect of addictive drugs and drug-paired contexts resist extinction and contribute to the high rate of relapse observed in drug addicts. Although it has been shown that extracellular signal-regulated kinase 1/2 (ERK1/2) activity in the nucleus accumbens (NAc) is modulated by the primary rewarding effect of opiates, little is known as to its role in the morphine-associated contextual memory. In the present study, we investigated the ERK1/2 activity indicated by phosphorylated ERK1/2 (pERK1/2) levels in rats using a morphine-induced conditioned place preference (CPP) procedure. Our results showed that, in rats that had undergone morphine conditioning, after testing (expression phase) pERK1/2 in the NAc shell but not the NAc core or the adjacent caudate putamen was specifically increased. pERK1/2 levels in several other parts of the brain involved in drug-seeking, such as the medial prefrontal cortex, dorsal hippocampus, and basolateral amygdala, showed no significant changes. A significant positive correlation was observed between the elevated pERK1/2 level in the NAc shell and the degree of conditioned preference for morphine-associated contexts. Bilateral injection of an inhibitor of ERK activation into the NAc shell attenuated ERK1/2 phosphorylation and prevented the expression of morphine CPP, but injections into the core did not. Selective inhibition of NR2B-containing NMDA receptor in the NAc shell by ifenprodil prevented CPP expression and down-regulated local ERK1/2 phosphorylation. These findings collectively suggest that recall of morphine-associated contextual memory depends specifically upon ERK1/2 activation in the NAc shell and that ERK1/2 phosphorylation is regulated by the upstream NR2B-containing NMDA receptor.

Essential role of protein kinase C in morphine-induced rewarding memory.

Protein kinase C (PKC) is involved in intra-cellular signal transduction in various physiological and pathological processes including substance abuse. In the present study, the role of PKC in morphine-induced rewarding memory was investigated using the conditioned place preference (CPP) model. We found a significant translocation of PKCs from cytosol to membrane component in nucleus accumbens (NAc) of morphine-conditioned rats in a dose-dependent manner. The translocation was reduced gradually with the maintenance of morphine-induced CPP. Specifically, the protein level of PKCγ in membrane of the NAc was increased in morphine CPP rats, and decreased during the attenuation of morphine-induced CPP, while the protein level of PKCγ in cytosol of the NAc showed an opposite change. Furthermore, the PKC translocation inhibitor γV5-3 impaired the morphine-induced CPP when microinjected into the NAc. These findings indicated that PKC, especially the γ isoform, is essential for the acquisition and maintenance of morphine-associated reward memory. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.

Expression of activity-regulated cytoskeleton-associated protein (Arc/Arg3.1) in the nucleus accumbens is critical for the acquisition, expression and reinstatement of morphine-induced conditioned place preference.

Activity-regulated cytoskeleton-associated protein (Arc), also known as activity-regulated gene 3.1 (Arg3.1), is an immediate early gene whose mRNA is selectively targeted to recently activated synaptic sites, where it is translated and enriched. This unique feature suggests a role for Arc/Arg3.1 in coupling synaptic activity to protein synthesis, leading to synaptic plasticity. Although the Arc/Arg3.1 gene has been shown to be induced by a variety of abused drugs and its protein has been implicated in diverse forms of long-term memory, relatively little is known about its role in drug-induced reward memory. In this study, we investigated the potential role of Arc/Arg3.1 protein expression in reward-related associative learning and memory using morphine-induced conditioned place preference (CPP) in rats. We found that (1) intraperitoneal (i.p.) injection of morphine (10mg/kg) increased Arc/Arg3.1 protein levels after 2h in the NAc core but not in the NAc shell. (2) In CPP experiments, Arc/Arg3.1 protein was increased in the NAc shell of rats following both morphine conditioning and the CPP expression test compared to rats that received the conditioning without the test or those that did not receive morphine conditioning. (3) Microinjection of Arc/Arg3.1 antisense oligodeoxynucleotide (AS) into the NAc core inhibited the acquisition, expression and reinstatement of morphine CPP; however, intra-NAc shell infusions of the AS only blocked the expression of CPP. These findings suggest that expression of the Arc/Arg3.1 protein in the NAc core is required for the acquisition, context-induced retrieval and reinstatement of morphine-associated reward memory, whereas Arc/Arg3.1 protein expression in the NAc shell is only critical for the context-induced retrieval of memory. As a result, Arc/Arg3.1 may be a potential therapeutic target for the prevention of drug abuse or the relapse of drug use.

[Effect of Rehmannia glutinosa Libosch water extraction on gene expression of proinsulin in type 2 diabetes mellitus rats].

OBJECTIVE: To investigate the mechanisms of treating 2-DM by Rehmannia glutinosa Libosch water extraction (RGLE). METHODS: The mRNA level of proinsulin in rats panreas tissue was examined by semi-quatitativa RT-PCR,and the protein was measured by SDS-PAGE. RESULTS: The mRNA and protein expressions of proinsulin in RGLE group were higher than those of diabetic model group (P<0.01). The levels of FPG decreased. FINS,IS, HbetaCI increased (P<0.01). CONCLUSION: It may be the mechanism how the RGLE to decline high FPG and cure the 2-DM.

[Effect of Rehmannia glutinosa water extraction on insulin resistance and gene expression of resistin in type 2 diabetes mellitus rats].

OBJECTIVE: To investigate the effect of Rehmannia glutinosa water extraction (RGL) on adipose metabolic disorder and gene expression of resistin in type 2 diabetes mellitus rats. METHOD: The wistar rats model of 2-DM were induced by high calorie feeding and small dose injection of STZ. Rats were randomly divided into diabetic model group, diabetic model treated with RGL (2.4 g x kg(-1) x d(-1)), RGL (1.2 g x kg(-1) x d(-1)), RGL (0. 6 g x kg(-1) x d(-1)) and normal control group. The levels of FPG, FINS, TG, HDL, LDL, CH and IR were measured, and the mRNA expression of resistin was determined by RT-PCR, the protein expression measured by SDS-PAGD at the end of 8 weeks. RESULT: The gene expression of resistin in RGL group were lower than that of diabetic model (P < 0.01). The levels of FPG, FINS, TG, LDL, CH, IR in RGL group were lower than that of diabetic model (P < 0.05), and HDL were higher (P < 0.05). CONCLUDE: RGL can improve insulin resistance in the experimental 2-DM rats, can effectively ameliorate adipose metabolic disturbance and decline IR and FINS by increasing the gene expression of resistin.