Analysis of the global burden of cervical cancer in young women aged 15-44 years old.

BACKGROUND: Understanding the burden of cervical cancer (CC) in young women aged 15-44 years old are essential for formulating effective preventive strategies. METHODS: Utilizing the Global Burden of Disease 2019 Study, we estimated incidence, disability-adjusted life-years (DALYs), years of life lost (YLLs) and years lived with disability (YLDs) due to CC among young women from 1990 to 2019. Additionally, we evaluated the temporal trends using estimated annual percentage changes (EAPCs) during this period. We conducted a decomposition analysis to assess the absolute contributions of three components: population growth, population age structure and epidemiologic changes. RESULTS: Globally, there were 187 609.22 incident cases of CC worldwide, resulting in 2621 917.39 DALYs in 2019. From1990 to 2019, the age-standardized rates were decline, only the age-standardized YLDs rate (EAPC = 0.02; 95% CI: -0.02 to 0.05) showed a stable trend. The largest increase in age-standardized incidence rate (ASIR) and age-standardized YLDs rate observed in the high-middle social demographic index (SDI) quintiles. Population growth and age structure changes were associated with substantial changes in cases of CC, especially in South Asia and East Asia. CONCLUSIONS: Globally, the burden of CC in young women continues to increase, as measured by the absolute number. As populations are growing and age structure changes were associated with substantial changes in cases of CC, governments will face increasing demand for treatment, and support services for CC, especially in South Asia and East Asia.

Functional polymorphisms in Benzo(a)Pyrene-induced toxicity pathways associated with the risk on laryngeal squamous cell carcinoma.

Benzo(a)Pyrene (BaP) is a well-known environmental carcinogen that poses a significant risk to human health. The pivotal genes and toxicity pathways have been identified as key events to construct the mode of action (MOA) of BaP. In this study, we focused on evaluating the association between genetic variants in BaP-disturbed toxicity pathways and the susceptibility of laryngeal squamous cell carcinoma (LSCC), based on the data of our previous genome-wide association analysis (GWAS). In addition, we investigated the biological roles of these significant polymorphisms by integrating bioinformatic annotation and experimental validation. Our findings revealed that 15 functional polymorphisms in AHR signaling, p53 signaling, NRF2 signaling, TGF-ß signaling, STAT3 signaling, and IL-8 signaling pathways were significantly associated with susceptibility to LSCC. Our study provides a novel approach for identifying novel risk genetic loci utilizing GWAS data, and suggests potential targets for early detection of LSCC in the future.

Potential Biomedical Limitations of Graphene Nanomaterials.

Graphene-family nanomaterials (GFNs) possess mechanical stiffness, optical properties, and biocompatibility making them promising materials for biomedical applications. However, to realize the potential of graphene in biomedicine, it must overcome several challenges that arise when it enters the body's circulatory system. Current research focuses on the development of tumor-targeting devices using graphene, but GFNs accumulated in different tissues and cells through different pathways, which can cause toxic reactions leading to cell apoptosis and body dysfunction when the accumulated amount exceeds a certain limit. In addition, as a foreign substance, graphene can induce complex inflammatory reactions with immune cells and inflammatory factors, potentially enhancing or impairing the body's immune function. This review discusses the biomedical applications of graphene, the effects of graphene materials on human immune function, and the biotoxicity of graphene materials.

Effect of a family-involvement combined aerobic and resistance exercise protocol on cancer-related fatigue in patients with breast cancer during postoperative chemotherapy: study protocol for a quasi-randomised controlled trial.

INTRODUCTION: Cancer-related fatigue (CRF) is one of the most common and debilitating side effects experienced by patients with breast cancer (BC) during postoperative chemotherapy. Family-involvement combined aerobic and resistance exercise has been introduced as a promising non-pharmacological intervention for CRF symptom relief and improving patients' muscle strength, exercise completion, family intimacy and adaptability and quality of life. However, evidence for the practice of home participation in combined aerobic and resistance exercise for the management of CRF in patients with BC is lacking. METHODS AND ANALYSIS: We present a protocol for a quasi-randomised controlled trial involving an 8-week intervention. Seventy patients with BC will be recruited from a tertiary care centre in China. Participants from the first oncology department will be assigned to the family-involvement combined aerobic and resistance exercise group (n=28), while participants from the second oncology department will be assigned to the control group that will receive standard exercise guidance (n=28). The primary outcome will be the Piper Fatigue Scale-Revised (R-PFS) score. The secondary outcomes will include muscle strength, exercise completion, family intimacy and adaptability and quality of life, which will be evaluated by the stand-up and sit-down chair test, grip test, exercise completion rate, Family Adaptability and Cohesion Scale, Second Edition-Chinese Version (FACESⅡ-CV) and Functional Assessment of Cancer Therapy -Breast (FACT-B) scale. Analysis of covariance will be applied for comparisons between groups, and paired t-tests will be used for comparison of data before and after exercise within a group. ETHICS AND DISSEMINATION: This study has been approved by the Ethics Committee of the First Affiliated Hospital of Dalian Medical University (PJ-KS-KY-2021-288). The results of this study will be published via peer-reviewed publications and presentations at conferences. TRAIL REGISTRATION NUMBER: ChiCTR2200055793.

The awareness and acceptance of HPV vaccines among parents of primary and junior high school students in China: a meta-analysis.

The awareness and acceptance of the human papillomavirus (HPV) vaccines among Chinese primary and junior high school students is limited. A meta-analysis was conducted to evaluate the awareness of HPV and HPV vaccines, as well as the acceptance of HPV vaccines, providing evidence-based strategies to promote HPV vaccination. Based on the databases of CNKI, Wanfang, VIP, PubMed, Embase, and Cochrane library, the literatures about the awareness of HPV and HPV vaccines, as well as the acceptance of HPV vaccines among parents of primary and junior high school students were collected from the inception to June 2023. Subgroup analysis was used to find the source of heterogeneity. Publication bias was evaluated using funnel plots and Egger's test. Fifteen literatures with 21,853 participants were included. The pooled HPV awareness, HPV vaccine awareness and acceptance rates among parents of primary and junior high school students in China were 42.90% (95% CI: 33.34%-52.47%), 28.11% (95% CI: 18.20%-43.41%), and 55.29% (95% CI: 45.85%-64.36%), respectively. The survey period and the proportion of female parents were the heterogeneity in awareness of HPV and HPV vaccines, as well as acceptance of HPV vaccines by subgroup analysis. Additionally, regional distribution emerged as another significant source of heterogeneity in HPV vaccine acceptance. The primary cause for parents' reluctance to vaccinate their children was theirs worries about the safety of the vaccines (66.21%). Though the awareness of HPV and its vaccines was low among parents of primary and junior high school students in China, the acceptance of HPV vaccines was relatively high. Strengthening health education and publicity was crucial to enhance awareness and acceptance, promoting HPV vaccination for effective cervical cancer prevention.

Design, synthesis, and evaluation of a novel series of mono-indolylbenzoquinones derivatives for the potential treatment of breast cancer.

Breast cancer is one of the most common cancers in the world, and pro-apototic drugs activating the apoptotic pathway are a strategy for anticancer therapy. To explore new antineoplastic agents, a series of novel mono-indolylbenzoquinone derivatives have been designed and synthesized. Compared with the lead bis-indolylbenzoquinones, most of the novel mono-indolylbenzoquinone derivatives have significantly increased their activity against A549, HeLa, and especially, MDA-MB-231 cell lines. Among them, 10d has the lowest IC50 value of 70 nM on MDA-MB-231 cells. Moreover, its oral toxicity is extremely low with an LD50 value of 374 mg/kg and no obvious liver and kidney damage to mice. 10d down-regulated Bcl-2, up-regulated Bax, and increased the release of cytochrome C, caspase3 and 9. 10d also up-regulated the expression of p53, catalase, and HTRA2/Omi. Therefore, 10d may exert its anticancer activity by activating apoptotic pathway and p53 expression. In vivo, 10d suppressed breast cancer 4T1 tumor growth with 36% inhibition ratio of tumor by intraperitoneal injection in mice. Furthermore, a cross-linked cyanoacrylate (CA)-based local sustained-release drug delivery systems (LSRDDSs) improved 10d anticancer activity to 49.8% inhibition of tumor growth. Taken together, 10d could be a promising drug candidate for clinical development to treat metastatic breast cancer.

Research Progress in Antineoplastic, Antibacterial, and Anti-inflammatory Activities of Seven-membered Heterocyclic Derivatives.

Seven-membered heterocyclic compounds are important drug scaffolds because of their unique chemical structures. They widely exist in natural products and show a variety of biological activities. They have been used commonly in central nervous system drugs in the past 30 years. In the past decade, many studies have been conducted on their activities, including antitumor, antibacterial, etc. Herein, we summarize the research advances in different kinds of seven-membered heterocyclic compounds containing nitrogen, oxygen, and sulfur heteroatoms with antitumor, antisepsis, and anti-inflammation activities in the past ten years, which are expected to be beneficial to the development and design of novel drugs for the corresponding indications.

Connexin43 promotes angiogenesis through activating the HIF-1α/VEGF signaling pathway under chronic cerebral hypoperfusion.

Chronic cerebral hypoperfusion, a major vascular contributor to vascular cognitive impairment and dementia, can exacerbate small vessel pathology. Connexin43, the most abundant gap junction protein in brain tissue, has been found to be critically involved in the pathological changes of vascular cognitive impairment and dementia caused by chronic cerebral hypoperfusion. However, the precise mechanisms underpinning its role are unclear. We established a mouse model via bilateral common carotid arteries stenosis on connexin43 heterozygous male mice and demonstrated that connexin43 improves brain blood flow recovery by mediating reparative angiogenesis under chronic cerebral hypoperfusion, which subsequently reduces the characteristic pathologies of vascular cognitive impairment and dementia including white matter lesions and irreversible neuronal injury. We additionally found that connexin43 mediates hypoxia inducible factor-1α expression and then activates the PKA signaling pathway to regulate vascular endothelial growth factor-induced angiogenesis. All the above findings were replicated in bEnd.3 cells treated with 375 µM CoCl2in vitro. These results suggest that connexin 43 could be instrumental in developing potential therapies for vascular cognitive impairment and dementia caused by chronic cerebral hypoperfusion.

LXW7 attenuates inflammation via suppressing Akt/nuclear factor kappa B and mitogen-activated protein kinases signaling pathways in lipopolysaccharide-stimulated BV2 microglial cells.

Microglia activation is closely linked to ischemia, various chronic neurodegenerative diseases (e.g., Alzheimer's disease, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis), and many other central nervous system diseases. Accumulating evidence suggests that depressing the microglial inflammatory response could be an effective treatment for inflammatory disorders. The integrin αvß3 inhibitor LXW7 has a neuroprotective effect; however, its anti-inflammatory effects and underlying mechanism remain unclear. Thus, we examined whether LXW7 would inhibit inflammatory cytokines and mediators, and we evaluated the potential mechanisms of its neuroprotective effects. Nitrite analysis revealed LXW7 reduced the nitric oxide (NO) level. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) suggested that LXW7 suppressed the expression of proinflammatory genes for tumor necrosis factor-alpha (TNF-α), interleukin 1-beta (IL-1ß), inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), and anti-inflammatory gene interleukin 10 (IL-10) at the messenger ribonucleic acid level. Enzyme-linked immunosorbent assay results demonstrated that LXW7 treatment reduced the expression of prostaglandin E2 (PGE2), TNF-α, IL-1ß and IL-10 at the protein level. Western blotting was conducted to confirm the upregulation of inflammatory factors, including iNOS and COX-2 at the protein level. LXW7 inhibited major genes in the Akt/NF-κB and c-Jun NH2-terminal kinase/ mitogen-activated protein kinases (JNK/MAPK) signaling pathways. Immunofluorescence revealed that LXW7 inhibited the nuclear translocation of nuclear factor kappa B (NF-κB). Thus, LXW7 effectively alleviated LPS-induced inflammatory damage and had neuroprotective effects. The anti-inflammatory effects of LXW7 may be associated with the inhibition of microglial activation via Akt/NF-κB and JNK/MAPK signaling pathways by blocking integrin αvß3 receptor. The present study's findings suggest that LXW7 has a substantial therapeutic potential for treating inflammatory and neurodegenerative diseases.

CeO2@PAA-LXW7 Attenuates LPS-Induced Inflammation in BV2 Microglia.

Microglia are the inherent immune effector cells in the central nervous system (CNS), are activated rapidly when the CNS is stimulated by ischaemia, infection, injury, etc. and participate in and aggravate the development of inflammatory reactions in the CNS. During the process of microglial activation, inflammatory factors such as TNF-α and IL-1ß and an abundance of reactive oxygen species (ROS)/reactive nitrogen species (RNS), are released by damaged nerve cells. LXW7 is a small molecule peptide and specifically binds with integrin αvß3. Cerium oxide nanoparticles (nanoceria) are strong free radical scavengers and are widely used in many studies. In this research, a model of inflammation was established using lipopolysaccharide (LPS) to induce BV2 microglia activation, and the effects of CeO2@PAA (synthetic nanoscale cerium oxide particles), LXW7 and CeO2@PAA-LXW7 were evaluated. We detected the expression level of inflammatory factors, the release of NO in BV2 cells and the generation of intracellular ROS. The expression levels of focal adhesion kinase (FAK) and signal transducer and activator of transcription 3 (STAT3) and their phosphorylated proteins were detected in BV2 microglia. We found that CeO2@PAA, LXW7 and CeO2@PAA-LXW7 all effectively inhibited the activation of BV2 microglia, reduced the production of cytokines and the release of NO and reduced the production of intracellular ROS. The three treatments all inhibited the phosphorylation of FAK and STAT3 in BV2 microglia. Regarding these effects, CeO2@PAA-LXW7 was more effective than the other two monotherapies. Our data indicate that CeO2@PAA, LXW7 and CeO2@PAA-LXW7 can exert a neuroprotective function by inhibiting the inflammatory response of LPS-induced BV2 microglia. LXW7 may inhibit the activation of FAK and STAT3 signals in combination with integrin αvß3 to restrain neuroinflammation and the antioxidative stress effect of cerium oxide; hence, CeO2@PAA-LXW7 can exert a more robust anti-inflammatory and neuroprotective effect via synergistically suppressing the ability of LXW7 to influence the integrin pathway and the free radical-scavenging ability of CeO2@PAA.

Prognostic Value of Albumin/Globulin Ratio in Survival and Lymph Node Metastasis in Patients with Cancer: A Systematic Review and Meta-analysis.

The impact of albumin to globulin ratio (AGR) on the prognosis of various human cancers has not been well established. Here, a systemic review and meta-analysis has been performed to comprehensively assess the relationships between AGR and lymph node metastasis (LNM) or overall survival (OS). Systematical search through six electronic databases has been carried out to identify reports involving the role of AGR on OS and LNM in human cancers. Hazard ratio (HR), odd ratio (OR) and their 95% confidence intervals (95% CI) were evaluated through meta-analysis according to standard steps. Of 403 studies retrieved, 14 eligible studies with 4136 patients were included in this study. The analysis based on random-effect model demonstrated that low AGR was significantly associated with poor OS in various cancers (HR=1.87, 95% CI 1.50-2.34; P < 0.001). Subsequent results showed a significant increase in the risk of LNM in the low AGR group when compared with high AGR group (HR=2.24; 95% CI=1.49-3.36; P<0.001). To conclusion, this study suggested that AGR was associated with OS and LNM in cancer patients and AGR may be a potential marker to assess prognosis of cancer patients. However, a large scale of samples and prospective studies are needed in the future to validate the role of AGR in practice.

Neuroprotective Effect of CeO2@PAA-LXW7 Against H2O2-Induced Cytotoxicity in NGF-Differentiated PC12 Cells.

CeO2 nanoparticles (nanoceria) have been used in many studies as a powerful free radical scavenger, and LXW7, a small-molecule peptide, can specifically target the integrin αvß3, whose neuroprotective effects have also been demonstrated. The objective of this study is to observe the neuroprotective effect and potential mechanism of CeO2@PAA-LXW7, a new compound that couples CeO2@PAA (nanoceria modified with the functional group of polyacrylic acid) with LXW7 via a series of chemical reactions, in H2O2-induced NGF-differentiated PC12 cells. We examined the effects of LXW7, CeO2@PAA, and CeO2@PAA-LXW7 on the viability of primary hippocampal neurons and found that there was no significant difference under control conditions, but increased cellular viability was observed in the case of H2O2-induced injury. We used H2O2-induced NGF-differentiated PC12 cells as the classical injury model to investigate the neuroprotective effect of CeO2@PAA-LXW7. In this study, LXW7, CeO2@PAA, and CeO2@PAA-LXW7 inhibit H2O2-induced oxidative stress by reducing the production of reactive oxygen species (ROS) and regulating Bax/Bcl-2, cleaved caspase-3 and mitochondrial cytochrome C (cyto C) in the apoptotic signaling pathways. We found that the levels of phosphorylation of focal adhesion kinase (FAK) and of signal transducer and activator of transcription 3 (STAT3) increased significantly in H2O2-induced NGF-differentiated PC12 cells, whereas LXW7, CeO2@PAA, and CeO2@PAA-LXW7 suppressed the increase to different degrees. Among the abovementioned changes, the inhibitory effect of CeO2@PAA-LXW7 on H2O2-induced changes, including the increases in the levels of p-FAK and p-STAT3, is more obvious than that of LXW7 or CeO2@PAA alone. In summary, these results suggest that integrin signaling participates in the regulation of apoptosis via the regulation of ROS and of the apoptosis pathway in H2O2-induced NGF-differentiated PC12 cells. LXW7, CeO2@PAA, and CeO2@PAA-LXW7 can play neuroprotective roles by counteracting the oxidative stress and apoptosis induced by H2O2 in NGF-differentiated PC12 cells. CeO2@PAA-LXW7 exerting a more powerful synergistic effect via the conjunction of LXW7 and CeO2@PAA.

Long non-coding RNA ANRIL in gene regulation and its duality in atherosclerosis.

The antisense transcript long non-coding RNA (lncRNA) (antisense non-coding RNA in the INK4 locus, ANRIL) is an antisense of the cyclin-dependent kinase inhibitor 2B (CDKN2B) gene on chromosome 9p21 that contains an overlapping 299-bp region and shares a bidirectional promoter with alternate open reading frame (ARF). In the context of gene regulation, ANRIL is responsible for directly recruiting polycomb group (PcG) proteins, including polycomb repressive complex-1 (PRC-1) and polycomb repressive complex-2 (PRC-2), to modify the epigenetic chromatin state and subsequently inhibit gene expression in cis-regulation. On the other hand, previous reports have indicated that ANRIL is capable of binding to a specific site or sequence, including the Alu element, E2F transcription factor 1 (E2F1), and CCCTC-binding factor (CTCF), to achieve trans-regulation functions. In addition to its function in cell proliferation, adhesion and apoptosis, ANRIL is very closely associated with atherosclerosis- related diseases. The different transcripts and the SNPs that are related to atherosclerotic vascular diseases (ASVD-SNPs) are inextricably linked to the development and progression of atherosclerosis. Linear transcripts have been shown to be a risk factor for atherosclerosis, whereas circular transcripts are protective against atherosclerosis. Furthermore, ANRIL also acts as a component of the inflammatory pathway involved in the regulation of inflammation, which is considered to be one of the causes of atherosclerosis. Collectively, ANRIL plays an important role in the formation of atherosclerosis, and the artificial modification of ANRIL transcripts should be considered following the development of this disease.

Comparison of binding interaction between ß-lactoglobulin and three common polyphenols using multi-spectroscopy and modeling methods.

Tea, coffee and fruit in dairy products are rich in polyphenols. The interaction mechanism between ß-lactoglobulin (ß-LG) and chlorogenic acid (CGA), ferulic acid (FA) and epigallocatechin-3-gallate (EGCG) was investigated. Fluorescence experiments proved that polyphenols quenched ß-LG fluorescence strongly in static mode and EGCG had stronger binding affinity toward ß-LG than CGA and FA. The main interaction force of EGCG binding with ß-LG was different from CGA and FA. Furthermore, circular dichroism and fourier transform infrared data indicated that polyphenols changed ß-LG secondary structure inducing a-helix to ß-structures transition. The surface hydrophobicity of ß-LG was also changed slightly by them according to surface hydrophobicity and particle size experiments. These results showed that the interaction mechanism of ß-LG with phenolic acid esters was different from it with phenolic acids. Besides, polyphenols had impact on the structure and functionality of ß-LG, which would be valuable in dairy processing industry.

Characterization of Gonadotrope Secretoproteome Identifies Neurosecretory Protein VGF-derived Peptide Suppression of Follicle-stimulating Hormone Gene Expression.

Reproductive function is controlled by the pulsatile release of hypothalamic gonadotropin-releasing hormone (GnRH), which regulates the expression of the gonadotropins luteinizing hormone and FSH in pituitary gonadotropes. Paradoxically, Fshb gene expression is maximally induced at lower frequency GnRH pulses, which provide a very low average concentration of GnRH stimulation. We studied the role of secreted factors in modulating gonadotropin gene expression. Inhibition of secretion specifically disrupted gonadotropin subunit gene regulation but left early gene induction intact. We characterized the gonadotrope secretoproteome and global mRNA expression at baseline and after Gαs knockdown, which has been found to increase Fshb gene expression (1). We identified 1077 secreted proteins or peptides, 19 of which showed mRNA regulation by GnRH or/and Gαs knockdown. Among several novel secreted factors implicated in Fshb gene regulation, we focused on the neurosecretory protein VGF. Vgf mRNA, whose gene has been implicated in fertility (2), exhibited high induction by GnRH and depended on Gαs In contrast with Fshb induction, Vgf induction occurred preferentially at high GnRH pulse frequency. We hypothesized that a VGF-derived peptide might regulate Fshb gene induction. siRNA knockdown or extracellular immunoneutralization of VGF augmented Fshb mRNA induction by GnRH. GnRH stimulated the secretion of the VGF-derived peptide NERP1. NERP1 caused a concentration-dependent decrease in Fshb gene induction. These findings implicate a VGF-derived peptide in selective regulation of the Fshb gene. Our results support the concept that signaling specificity from the cell membrane GnRH receptor to the nuclear Fshb gene involves integration of intracellular signaling and exosignaling regulatory motifs.

Growth differentiation factor 9 (GDF9) forms an incoherent feed-forward loop modulating follicle-stimulating hormone ß-subunit (FSHß) gene expression.

Gonadotropin-releasing hormone (GnRH) is secreted in brief pulses from the hypothalamus and regulates follicle-stimulating hormone ß-subunit (FSHß) gene expression in pituitary gonadotropes in a frequency-sensitive manner. The mechanisms underlying its preferential and paradoxical induction of FSHß by low frequency GnRH pulses are incompletely understood. Here, we identify growth differentiation factor 9 (GDF9) as a GnRH-suppressed autocrine inducer of FSHß gene expression. GDF9 gene transcription and expression were preferentially decreased by high frequency GnRH pulses. GnRH regulation of GDF9 was concentration-dependent and involved ERK and PKA. GDF9 knockdown or immunoneutralization reduced FSHß mRNA expression. Conversely, exogenous GDF9 induced FSHß expression in immortalized gonadotropes and in mouse primary pituitary cells. GDF9 exposure increased FSH secretion in rat primary pituitary cells. GDF9 induced Smad2/3 phosphorylation, which was impeded by ALK5 knockdown and by activin receptor-like kinase (ALK) receptor inhibitor SB-505124, which also suppressed FSHß expression. Smad2/3 knockdown indicated that FSHß induction by GDF9 involved Smad2 and Smad3. FSHß mRNA induction by GDF9 and GnRH was synergistic. We hypothesized that GDF9 contributes to a regulatory loop that tunes the GnRH frequency-response characteristics of the FSHß gene. To test this, we determined the effects of GDF9 knockdown on FSHß induction at different GnRH pulse frequencies using a parallel perifusion system. Reduction of GDF9 shifted the characteristic pattern of GnRH pulse frequency sensitivity. These results identify GDF9 as contributing to an incoherent feed-forward loop, comprising both intracellular and secreted components, that regulates FSHß expression in response to activation of cell surface GnRH receptors.

Gonadotrope-specific expression and regulation of ovine follicle stimulating hormone Beta: transgenic and adenoviral approaches using primary murine gonadotropes.

The beta subunit of follicle stimulating hormone (FSHB) is expressed specifically in pituitary gonadotropes in vertebrates. Transgenic mouse studies have shown that enhancers in the proximal promoter between -172/-1 bp of the ovine FSHB gene are required for gonadotrope expression of ovine FSHB. These enhancers are associated with regulation by activins and gonadotropin releasing hormone (GnRH). Additional distal promoter sequence between -4741/-750 bp is also required for expression. New transgenic studies presented here focus on this distal region and narrow it to 1116 bp between -1866/-750 bp. In addition, adenoviral constructs were produced to identify these critical distal sequences using purified primary mouse gonadotropes as an in vitro model system. The adenoviral constructs contained -2871 bp, -750 bp or -232 bp of the ovine FSHB promoter. They all showed gonadotrope-specific regulation since they were induced only in purified primary gonadotropes by activin A (50 ng/ml) and inhibited by GnRH (100 nM) in the presence of activin (except -232FSHBLuc). However, basal expression of all three viral constructs (in the presence of follistatin to block cellular induction by activin) was relatively high in pituitary non-gonadotropes as well as gonadotropes. Thus, gonadotrope-specific regulation associated with the proximal promoter was observed as expected, but the model was blind to distal promoter elements between -2871/-750 necessary for gonadotrope-specific expression of ovine FSHB in vivo. The new adenoviral-based in vitro technique did detect, however, a novel GnRH response element between -750 bp and -232 bp of the ovine FSHB promoter. We conclude that adenoviral-based studies in primary gonadotropes can adequately recognize regulatory elements on the ovine FSHB promoter associated with gonadotrope-specific regulation/expression, but that more physiologically based techniques, such as transgenic studies, will be needed to identify sequences between -1866/-750 bp of the ovine FSHB promoter that are also required for tissue/cell specific expression in vivo.

G proteins and autocrine signaling differentially regulate gonadotropin subunit expression in pituitary gonadotrope.

Gonadotropin-releasing hormone (GnRH) acts at gonadotropes to direct the synthesis of the gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone (LH). The frequency of GnRH pulses determines the pattern of gonadotropin synthesis. Several hypotheses for how the gonadotrope decodes GnRH frequency to regulate gonadotropin subunit genes differentially have been proposed. However, key regulators and underlying mechanisms remain uncertain. We investigated the role of individual G proteins by perturbations using siRNA or bacterial toxins. In LßT2 gonadotrope cells, FSHß gene induction depended predominantly on Gα(q/11), whereas LHß expression depended on Gα(s). Specifically reducing Gα(s) signaling also disinhibited FSHß expression, suggesting the presence of a Gα(s)-dependent signal that suppressed FSH biosynthesis. The presence of secreted factors influencing FSHß expression levels was tested by studying the effects of conditioned media from Gα(s) knockdown and cholera toxin-treated cells on FSHß expression. These studies and related Transwell culture experiments implicate Gα(s)-dependent secreted factors in regulating both FSHß and LHß gene expression. siRNA studies identify inhibinα as a Gα(s)-dependent GnRH-induced autocrine regulatory factor that contributes to feedback suppression of FSHß expression. These results uncover differential regulation of the gonadotropin genes by Gα(q/11) and by Gα(s) and implicate autocrine and gonadotrope-gonadotrope paracrine regulatory loops in the differential induction of gonadotropin genes.

Elucidation of mechanisms of the reciprocal cross talk between gonadotropin-releasing hormone and prostaglandin receptors.

We recently described a novel GnRH receptor signaling pathway mediated by the prostaglandins (PGs) F(2alpha) and PGI(2), which acts through an autocrine/paracrine modality to limit autoregulation of the GnRH receptor and inhibit LH but not FSH release. Here we further explore the cross talk between GnRH and the PG receptors. GnRH stimulates arachidonic acid (AA) release from LbetaT2 gonadotrope cells via the Ca(2+)-independent phospholipase A(2) (iPLA(2)) and not via the more common Ca(2+)-dependent cytosolic phospholipase A(2)alpha (cPLA(2)alpha). AA release was followed by a marked induction of cyclooxygenase (COX)-1 and COX-2 by GnRH via the protein kinase C/c-Src/phosphatidylinositol 3-kinase/MAPK pathway. COX-2 transcription by GnRH is mediated by the two nuclear factor-kappaB sites and the CCAAT/enhancer-binding protein site within its promoter. Indeed, GnRH stimulates p65/RelA phosphorylation (22-fold) in LbetaT2 cells and the two nuclear factor-kappaB sites apparently act as a composite response element. Although GnRH stimulates cAMP formation in LbetaT2 cells, we found no role for cAMP acting via the cAMP response element site in the COX-2 promoter. PGF(2alpha), PGI(2), or PGE(2) had no effect on GnRH-stimulated ERK, c-Jun N-terminal kinase, and p38MAPK activation or on GnRH- and high K(+)-stimulated intracellular Ca(2+) elevation in LbetaT2 and gonadotropes in primary culture. Although, PGF(2alpha), PGI(2), and PGE(2) reduced GnRH-stimulated cAMP formation, we could not correlate it to the inhibition of GnRH receptor expression, which is exerted only by PGF(2alpha) and PGI(2.) Hence, the inhibition by PGF(2alpha) and PGI(2) of the autoregulation of GnRH receptor expression is most likely mediated via inhibition of GnRH-stimulated phosphoinositide turnover and not by inhibition of Ca(2+) elevation and MAPK activation.