Dual Role of the P2X7 Receptor in Dendritic Outgrowth during Physiological and Pathological Brain Development.

At high levels, extracellular ATP operates as a "danger" molecule under pathologic conditions through purinergic receptors, including the ionotropic P2X7 receptor (P2X7R). Its endogenous activation is associated with neurodevelopmental disorders; however, its function during early embryonic stages remains largely unclear. Our objective was to determine the role of P2X7R in the regulation of neuronal outgrowth. For this purpose, we performed Sholl analysis of dendritic branches on primary hippocampal neurons and in acute hippocampal slices from WT mice and mice with genetic deficiency or pharmacological blockade of P2X7R. Because abnormal dendritic branching is a hallmark of certain neurodevelopmental disorders, such as schizophrenia, a model of maternal immune activation (MIA)-induced schizophrenia, was used for further morphologic investigations. Subsequently, we studied MIA-induced behavioral deficits in young adult mice females and males. Genetic deficiency or pharmacological blockade of P2X7R led to branching deficits under physiological conditions. Moreover, pathologic activation of the receptor led to deficits in dendritic outgrowth on primary neurons from WT mice but not those from P2X7R KO mice exposed to MIA. Likewise, only MIA-exposed WT mice displayed schizophrenia-like behavioral and cognitive deficits. Therefore, we conclude that P2X7R has different roles in the development of hippocampal dendritic arborization under physiological and pathologic conditions.SIGNIFICANCE STATEMENT Our main finding is a novel role for P2X7R in neuronal branching in the early stages of development under physiological conditions. We show how a decrease in the expression of P2X7R during brain development causes the receptor to play pathologic roles in adulthood. Moreover, we studied a neurodevelopmental model of schizophrenia and found that, at higher ATP concentrations, endogenous activation of P2X7R is necessary and sufficient for the development of positive and cognitive symptoms.

A proof-of-concept study on bioorthogonal-based pretargeting and signal amplify radiotheranostic strategy.

BACKGROUND: Radiotheranostics differs from the vast majority of other cancer therapies in its capacity for simultaneous imaging and therapy, and it is becoming more widely implemented. A balance between diagnostic and treatment requirements is essential for achieving effective radiotheranostics. Herein, we propose a proof-of-concept strategy aiming to address the profound differences in the specific requirements of the diagnosis and treatment of radiotheranostics. RESULTS: To validate the concept, we designed an s-tetrazine (Tz) conjugated prostate-specific membrane antigen (PSMA) ligand (DOTA-PSMA-Tz) for 68Ga or 177Lu radiolabeling and tumor radiotheranostics, a trans-cyclooctene (TCO) modified Pd@Au nanoplates (Pd@Au-PEG-TCO) for signal amplification, respectively. We then demonstrated this radiotheranostic strategy in the tumor-bearing mice with the following three-step procedures: (1) i.v. injection of the [68Ga]Ga-PSMA-Tz for diagnosis; (2) i.v. injection of the signal amplification module Pd@Au-PEG-TCO; (3) i.v. injection of the [177Lu]Lu-PSMA-Tz for therapy. Firstly, this strategy was demonstrated in 22Rv1 tumor-bearing mice via positron emission tomography (PET) imaging with [68Ga]Ga-PSMA-Tz. We observed significantly higher tumor uptake (11.5 ± 0.8%ID/g) with the injection of Pd@Au-PEG-TCO than with the injection [68Ga]Ga-PSMA-Tz alone (5.5 ± 0.9%ID/g). Furthermore, we validated this strategy through biodistribution studies of [177Lu]Lu-PSMA-Tz, with the injection of the signal amplification module, approximately five-fold higher tumor uptake of [177Lu]Lu-PSMA-Tz (24.33 ± 2.53% ID/g) was obtained when compared to [177Lu]Lu-PSMA-Tz alone (5.19 ± 0.26%ID/g) at 48 h post-injection. CONCLUSION: In summary, the proposed strategy has the potential to expand the toolbox of pretargeted radiotherapy in the field of theranostics.

Radiotracers for Nuclear Imaging of Reactive Oxygen Species: Advances Made So Far.

Reactive oxygen species (ROS) are a cluster of highly reactive and short-lived oxygen-containing molecules that lead to metabolic disorders where production exceeds catabolism in an organism. Many specific radiotracers for positron/single-photon emission tomography have been developed to reveal the discrepancy of ROS levels in normal and damaged tissues and further clarify the relationship between ROS and diseases. This review summarizes the advances achieved for the development of ROS radiotracers to date. The structure design, radiosynthesis, and imaging performance of existing radiotracers are discussed with the individual ROS-response mechanisms highlighted.

MicroPET imaging of bacterial infection with nitroreductase-specific responsive 18F-labelled nitrogen mustard analogues.

PURPOSE: Bacterial infection and antibiotic resistance are serious threats to human health. This study aimed to develop two novel radiotracers, 18F-NTRP and 18F-NCRP, that possess a specific nitroreductase (NTR) response to image deep-seated bacterial infections using positron emission tomography (PET). This method can distinguish infection from sterile inflammation. METHODS: 18F-NTRP and 18F-NCRP were synthesized via a one-step method; all the steps usually involved in tracer radiosynthesis were successfully adapted in the All-In-One automated module. After the physiochemical properties of 18F-NTRP and 18F-NCRP were characterized, their specificity and selectivity for NTR were verified in E. coli and S. aureus. The ex vivo biodistribution of the tracers was evaluated in normal mice. MicroPET-CT imaging was performed in mouse models of bacterial infection and inflammation after the administration of 18F-NTRP or 18F-NCRP. RESULTS: Fully automated radiosynthesis of 18F-NTRP and 18F-NCRP was achieved within 90-110 min with overall decay-uncorrected, isolated radiochemical yields of 21.24 ± 4.25% and 11.3 ± 3.78%, respectively. The molar activities of 18F-NTRP and 18F-NCRP were 320 ± 40 GBq/µmol and 275 ± 33 GBq/µmol, respectively. In addition, 18F-NTRP and 18F-NCRP exhibited high selectivity and specificity for NTR response. PET-CT imaging in bacteria-infected mouse models with 18F-NTRP or 18F-NCRP showed significant radioactivity uptake in either E. coli- or S. aureus-infected muscles. The uptake for E. coli-infected muscles, 2.4 ± 0.2%ID/g with 18F-NTRP and 4.05 ± 0.49%ID/g with 18F-NCRP, was up to three times greater than that for uninfected control muscles. Furthermore, for both 18F-NTRP and 18F-NCRP, the uptake in bacterial infection was 2.6 times higher than that in sterile inflammation, allowing an effective distinction of infection from inflammation. CONCLUSION: 18F-NTRP and 18F-NCRP are worth further investigation to verify their potential clinical application for distinguishing bacterial infection from sterile inflammation via their specific NTR responsiveness.

A novel 18F-labeled agonist for PET imaging of stimulator of interferon gene expression in tumor-bearing mice.

PURPOSE: Stimulator of interferon genes (STING) protein plays a vital role in the immune surveillance of tumor microenvironment. Monitoring STING expression in tumors benefits the relevant STING therapy. This study aimed to develop a novel 18F-labeled agonist, dimeric amidobenzimidazole (diABZI), and firstly evaluate the feasibility of noninvasive positron emission tomography (PET) imaging of STING expression in the tumor microenvironment. METHODS: An analog of the STING agonist NOTA-DABI was synthesized and labeled with 18F via Al18F-NOTA complexation (denoted as [18F]F-DABI). Physicochemical properties, STING protein-binding affinity, and specificity of [18F]F-DABI were evaluated using cell uptake and docking assays. In vivo small-animal PET imaging and biodistribution studies of [18F]F-DABI in tumor-bearing mice were performed to verify the pharmacokinetics and tumor targeting ability. The correlation between tumor uptake and STING expression was also analyzed. RESULTS: [18F]F-DABI was produced conveniently with high radiochemical yield (44 ± 15%), radiochemical purity (> 97%) and molar activity (15-30 GBq/µmol). In vitro binding assays demonstrated that [18F]F-DABI has a favorable affinity and specificity for STING with a KD of 12.98 ± 2.07 nM. In vivo studies demonstrated the specificity of [18F]F-DABI for PET imaging of STING expression with B16F10 tumor uptake of 10.93 ± 0.93%ID/g, which was significantly different from that of blocking groups (3.13 ± 0.88%ID/g, ***p < 0.0001). Furthermore, tumor uptake of [18F]F-DABI was well positively correlated with STING expression in different tumor types. Biodistribution results demonstrated that [18F]F-DABI was predominately uptaken in the liver and intestines, indicating its hepatobiliary elimination. CONCLUSION: This proof-of-concept study demonstrated a STING-binding radioligand for PET imaging, which could be used as a potential companion diagnostic tool for related STING-agonist therapies.

Risk factors for postoperative urinary retention in patients undergoing colorectal surgery: a systematic review and meta-analysis.

PURPOSE: Postoperative urinary retention (POUR) is a common complication following colorectal surgery. The incidence of POUR among colorectal surgery patients varies widely, and the risk factors and outcomes of POUR are also debatable. This meta-analysis aims to systematically evaluate the risk factors for POUR in patients after colorectal surgery. METHODS: PubMed, Web of Science, the Cochrane Library, Embase, Medline, and Chinese databases (CBM, CNKI, and WanFang Databases) were searched to identify relevant cohort studies (from inception to August 2022). Two researchers independently conducted literature quality evaluation and data extraction. All data were analyzed by using the Review Manager 5.4 software. RESULTS: Nineteen studies with 101,025 patients were included in this meta-analysis. The risk factors for POUR in colorectal surgery patients were male sex, older age, diabetes mellitus, urological diseases, tumor location in the lower rectum, APR, laparoscopic surgery, operation time ≥ 4 h, postoperative date of urinary catheter removal, excessive intraoperative intravenous fluid volume, and postoperative ileus. The postoperative anastomotic leak, on the other hand, was not a risk factor for POUR. CONCLUSIONS: Multiple risk factors influence the incidence of POUR in patients undergoing colorectal surgery. To reduce the incidence of POUR in colorectal surgery patients, medical staff should identify risk factors early and enforce interventions to prevent them.

Highly Specific and Sensitive Radioiodinated Agent for In Vivo Imaging of Superoxide through Superoxide-Initiated Retention.

Superoxide (O2•-) is a specific molecular target for xenobiotics, cytokines, and bacteria during inflammatory diseases. The aim of this study is to develop a single-photon emission computed tomography (SPECT) imaging agent and to quantify the distribution of O2•- in vivo. 125/131I-PISO was obtained in good radiochemical yield (65.4 ± 9.2%) and high radiochemical purity (>98%) after HPLC purification. 125/131I-PISO (log P = 2.46) could be oxidized by O2•- selectively and sensitively, converted to a hydrophilic compound 125/131I-PISA (log P = -1.62) with negative charge simultaneously and conglutinated with biomolecules by electrostatic interactions. The specific accumulation of 131I-PISA in the O2•- rich region were verified in cell efflux assay and SPECT/CT imaging in situ O2•- enrichment model mice. SPECT/CT imaging showed higher accumulation of 125I-PISO in the inflamed ankles compared to the control. Radioiodinated PISO is a potential SPECT agent to image O2•- distribution in vivo through specific and sensitive O2•- triggered retention.

Caregiver Burden and Readiness in Patients with Moderate and Severe Traumatic Brain Injury: The Chain Mediation Effect of Disease Uncertainty and Mental Resilience.

OBJECTIVE: To analyze the mediating effects of caregiver illness uncertainty and psychological resilience in caregiver burden and readiness in patients with moderate-to-severe traumatic brain injuries (TBIs). This can help improve caregiver readiness in patients with moderate-to-severe TBIs. METHODS: A purposive sampling method was used to recruit patients with moderate-to-severe TBIs, and their caregivers, who were hospitalized in the Department of Neurosurgery of the Affiliated Hospital of Yangzhou University between October 2022 and August 2023. The Zarit Caregiver Burden Interview, Mishel Uncertainty In Scale for Family Member, Connor-Davidson Resilience Scale, and Caregivers Preparedness Scale, as well as general information questionnaire, were used to conduct the survey. RESULTS: Caregiver readiness correlated with caregiver burden, illness uncertainty, and psychological resilience in patients with moderate-to-severe TBI (P < 0.01). Caregiver readiness was not only directly affected by caregiver burden (95% confidence interval: -0.510, -0.196) but was also affected through the chain mediation of illness uncertainty and psychological resilience (95% confidence interval: -0.146, -0.011). CONCLUSIONS: Caregiver burden in patients with moderate-to-severe TBI influences caregiver readiness levels and is mediated by illness uncertainty and psychological resilience. By improving caregivers' illness uncertainty and increasing their psychological resilience, the impact of low caregiver readiness caused by high caregiver burden could be reduced.

Effect of pueraria on left ventricular remodelling in HFrEF: A systematic review and meta-analysis.

BACKGROUND: Heart failure with reduced ejection fraction (HFrEF) is a prevalent cardiovascular disease globally, posing a significant burden on healthcare and society. Left ventricular remodelling is the primary pathology responsible for HFrEF development and progression, leading to increased morbidity and mortality. Pueraria, a traditional Chinese herbal medicine and food, is commonly used in China to treat HFrEF. Accumulating evidence suggests that pueraria can effectively reverse left ventricular remodelling in HFrEF patients. This meta-analysis aims to assess the impact of pueraria on left ventricular remodelling in HFrEF patients. METHODS: Eight electronic databases, including PubMed, EMBASE, Clinicaltrials.gov, Cochrane Library, Wanfang, CNKI, CQVIP, and CBM were searched for literature from inception to June 2023. All randomized controlled trials (RCTs) using pueraria in the treatment of HFrEF were included. The Cochrane Risk of Bias tool was utilized for RCTs' methodological evaluation, while Review Manager 5.4.1 was used to analyze the data. RESULTS: Nineteen RCTs with a total of 1,911 patients (1,077 males and 834 females) were identified. Meta-analysis indicated that combination medication of pueraria and conventional medicine (CM) was superior to the CM alone in raising left ventricular ejection fraction (LVEF; MD = 6.46, 95% CI, 4.88 to 8.04, P < 0.00001), and decreasing left ventricular end-diastolic diameter (LVEDD; MD = -4.78, 95% CI, -6.55 to -3.01, P < 0.00001), left ventricular end-Systolic diameter (LVESD; MD = -3.98, 95% CI, -5.98 to -1.99, P < 0.00001) and N-terminal pro-brain natriuretic peptide (NT-proBNP; MD = -126.16, 95% CI, -185.30 to -67.03, P < 0.0001). Besides, combination medication improved clinical efficacy rate (RR = 3.42, 95% CI, 2.54 to 4.59, P < 0.00001), 6-min walk test (6-MWT; MD = 65.54, 95% CI, 41.77 to 89.31, P < 0.00001), and TCM syndrome score efficacy (RR = 3.03, 95% CI, 1.57 to 5.83, P = 0.0009). Regarding safety, no difference was observed for adverse events (RR = 0.59, 95% CI, 0.22 to 1.54, P = 0.28). CONCLUSION: The use of pueraria combined with conventional medicine in HFrEF patients has superiority over conventional medicine alone in ameliorating cardiac function and reversing left ventricular remodeling. Moreover, combination medication has no increase in adverse drug events. Given some limitations, more prudence and high-quality clinical trials are needed in the future to verify the conclusions.

P2X7 purinergic receptor modulates dentate gyrus excitatory neurotransmission and alleviates schizophrenia-like symptoms in mouse.

ATP-gated P2X7 receptors (P2X7Rs) play a crucial role in brain disorders. However, how they affect normal and pathological synaptic transmission is still largely unclear. Here, by using whole-cell patch-clamp technique to record AMPA- and NMDA receptor-mediated excitatory postsynaptic currents (s/mEPSCs) in dentate gyrus granule cells (DG GCs), we revealed a modulation by P2X7Rs of presynaptic sites, especially originated from entorhinal cortex (EC)-GC path but not the mossy cell (MC)-GC path. The involvement of P2X7Rs was confirmed using a pharmacological approach. Additionally, the acute activation of P2X7Rs directly elevated calcium influx from EC-GC terminals. In postnatal phencyclidine (PCP)-induced mouse model of schizophrenia, we observed that P2X7R deficiency restored the EC-GC synapse alteration and alleviated PCP-induced symptoms. To summarize, P2X7Rs participate in the modulation of GC excitatory neurotransmission in the DG via EC-GC pathway, contributing to pathological alterations of neuronal functions leading to neurodevelopmental disorders.

Glial Purinergic Signaling-Mediated Oxidative Stress (GPOS) in Neuropsychiatric Disorders.

Oxidative stress (OS) has been implicated in the progression of multiple neuropsychiatric disorders, including schizophrenia (SZ), major depressive disorder (MDD), bipolar disorder, and autism. However, whether glial purinergic signaling interaction with oxidative/antioxidative system displays an important role in neuropsychiatric disorders is still unclear. In this review, we firstly summarize the oxidative/antioxidative pathways shared in different glial cells and highlight the cell type-specific difference in response to OS. Then, we collect the evidence showing the regulation of purinergic signaling in OS with an emphasis on adenosine and its receptors, P2Y1 receptor in the P2Y family and P2X7receptor in the P2X family. Available data shows that the activation of P1 receptors and P2X accelerates the OS; reversely, the activation of the P2Y family (P2Y1) causes protective effect against OS. Finally, we discuss current findings demonstrating the contribution of the purinergic signaling system to neuropsychiatric disorders and point out the potential role of OS in this process to propose a "glial purinergic-oxidative stress" ("GPOS") hypothesis for future development of therapeutic strategies against a variety of neuropsychiatric disorders.

Synergistically interactive P-Co-N bonding states in cobalt phosphide-decorated covalent organic frameworks for enhanced photocatalytic hydrogen evolution.

Non-noble materials with high efficiency and stability are essential for renewable energy applications. Herein, cobalt phosphide nanoparticles-decorated covalent organic frameworks (CTF-CoP) are synthesized via an in situ self-assembly method combined with the calcination process. In such a configuration, an intimate interaction between CoP and CTF matrix is gained through the Co-N chemical bonds, which not only significantly enhance the recyclability of CoP nanoparticles but also significantly improve the charge separation efficiency. Besides, the synergistically interactive Pδ--Coδ+-Nδ- states induced by the polarization effect of N-anchoring sites benefit for the adsorption and dissociation of water molecules in CTF-CoP. Consequently, CTF-CoP exhibits a higher photocatalytic hydrogen evolution rate (261.7 µmol g-1 h-1) and better durability as compared with the physically fixed CTF/CoP composite (64.8 µmol g-1 h-1) and even the noble metal-based CTF-Pt (191.3 µmol g-1 h-1). This work provides an avenue to construct highly stable non-noble photocatalyst for energy conversion and also emphasizes the potential of CTFs in constructing efficient heterojunctions.

68Ga-Labeled Maleimide for Blood Pool and Lymph PET Imaging through Covalent Bonding to Serum Albumin In Vivo.

This study aims to develop a novel 68Ga-labeled tracer, which can covalently bind to albumin in vivo based on the maleimide-thiol strategy, and to evaluate its potential applications using positron emission tomography (PET). 68Ga-labeled maleimide-monoamide-DOTA (denoted as [68Ga]Ga-DM) was prepared conveniently with a high radiochemical yield (>90%) and radiochemical purity (>99%). Its molar activity was calculated as 249.60 ± 68.50 GBq/µmol, and the octanol-water partition coefficient (LogP) was -3.15 ± 0.08 with good stabilities. In vitro experiments showed that [68Ga]Ga-DM can bind to albumin efficiently and rapidly, with a binding fraction of over 70%. High uptake and excellent retention in blood were observed with a long half-life (t 1/2Z) of 190.15 ± 24.14 min, which makes it possible for blood pool PET imaging with high contrast. The transient micro-bleeding in the rat model was detected successfully with PET imaging. In addition, the uptakes of [68Ga]Ga-DM in the inflammatory popliteal lymph nodes depend on the severity (5.90% ID/g and 2.32% ID/g vs 1.01% ID/g for healthy lymph nodes at 0.5 h post-injection) indicating its feasibility for lymphatic imaging. In conclusion, a novel 68Ga-labeled tracer was prepared with high efficiency and yield in mild conditions. Based on the promising properties of bonding covalently to albumin, great stability, high blood contrast with a long half-life, and well environmental tolerance, [68Ga]Ga-DM could be developed as a potential tracer for PET imaging of blood pool, bleeding, and vascular permeability alteration diseases in the clinic.

Caffeine consumption and schizophrenia: A highlight on adenosine receptor-independent mechanisms.

Schizophrenia is a common psychiatric disorder which affects approximately 1% of the population worldwide. However, the complexity of etiology, treatment resistance and side effects induced by current antipsychotics, relapse prevention, and psychosocial rehabilitation are still to be uncovered. Caffeine, as the world's most widely consumed psychoactive drug, plays a crucial role in daily life. Plenty of preclinical and clinical evidence has illustrated that caffeine consumption could have a beneficial effect on schizophrenia. In this review, we firstly summarize the factors associated with the caffeine-induced beneficial effect. Then, a variety of mechanism of actions independent of adenosine receptor signaling will be discussed with an emphasis on the potential contribution of the microbiome-gut-brain axis to provide more possibilities for future therapeutic, prognosis, and social rehabilitation strategy.

Ascorbic acid supplementation in type 2 diabetes mellitus: A protocol for systematic review and meta-analysis.

BACKGROUND: Diabetes is one of the most common chronic diseases in the world. In recent years, with the continuous improvement of people's living standards and changes in dietary structure, the incidence of diabetes is gradually increasing. Studies have shown that ascorbic acid supplementation can reduce blood glucose, increase insulin synthesis and secretion, improve insulin resistance, and reduce the occurrence and development of complications of type 2 diabetes mellitus (T2DM). However, relevant studies have common problems such as the lack of large sample studies and low quality of included studies. Therefore, it is needed that we meta-analyze the clinical trials with high quality to elucidate the efficacy and safety of ascorbic acid supplementation in patients with T2DM. METHODS: We will search randomized controlled trials published by PubMed, Embase, the Cochrane Library, Web of Science, and the Clinical Trials.gov website from inception to August 2020 on the effects of ascorbic acid supplementation on blood glucose, glycosylated hemoglobin, serum insulin, insulin resistance and other variables in T2DM patients with no language restrictions. The retrieval adopts the combination of medical subject headings and random words, and traces the references of the included literature to supplement the acquisition of relevant literature. Two researchers will independently screen the retrieved literature, extract the data and cross-check, and the Review Manage software V5.3.0 will be utilized for meta-analysis. RESULTS: Our study will provide a high-quality and in-depth comprehensive analysis of the effects of ascorbic acid supplementation on blood glucose control, glycosylated hemoglobin and insulin resistance in type 2 diabetic patients. CONCLUSION: This systematic review and meta-analysis concerning randomized controlled trials of ascorbic acid supplementation for type 2 diabetic patients will provide a new direction and strong evidence to evaluate whether ascorbic acid supplementation is of benefit to glucose control and insulin resistance in T2DM. PROSPERO REGISTRATION NUMBER: CRD 42019146826.

Controllable stripping of radiolabeled group in vivo to optimize nuclear imaging via NO-responsive bioorthogonal cleavage reaction.

A novel "turn-off" strategy for controllable radionuclide clearance is established. 1,4-dihydropyridine (DHP) is used as a conditional linker to connect a radioisotope labeled moiety and nano-agent. A highly specific, sensitive and effective C-C bond cleavage of DHP happens in vivo when treated with nitric oxide which is provided by glyceryl trinitrate (GTN). The radioactive cut-off part from the nanoparticle is observed to be cleared quickly by microSPECT-CT. 3-5 times decreases of radioactivity in the blood, kidneys, intestine, heart and lungs are observed after GTN treatment in a biodistribution assay. The radioactivity redistribution indicates that the radioactive leaving part is indeed cut off and the radionuclide metabolism accelerated. Organ level internal dose assessment reveals the GTN treated groups carry only ½ the radiation dose of the control group. Collectively, a feasible pathway for controllable radionuclide clearance is for the first time provided for high contrast and low radiation nuclear imaging.

Role of P2 receptors in normal brain development and in neurodevelopmental psychiatric disorders.

The purinergic signaling system, including P2 receptors, plays an important role in various central nervous system (CNS) disorders. Over the last few decades, a substantial amount of accumulated data suggest that most P2 receptor subtypes (P2X1, 2, 3, 4, 6, and 7, and P2Y1, 2, 6, 12, and 13) regulate neuronal/neuroglial developmental processes, such as proliferation, differentiation, migration of neuronal precursors, and neurite outgrowth. However, only a few of these subtypes (P2X2, P2X3, P2X4, P2X7, P2Y1, and P2Y2) have been investigated in the context of neurodevelopmental psychiatric disorders. The activation of these potential target receptors and their underlying mechanisms mainly influence the process of neuroinflammation. In particular, P2 receptor-mediated inflammatory cytokine release has been indicated to contribute to the complex mechanisms of a variety of CNS disorders. The released inflammatory cytokines could be utilized as biomarkers for neurodevelopmental and psychiatric disorders to improve the early diagnosis intervention, and prognosis. The population changes in gut microbiota after birth are closely linked to neurodevelopmental/neuropsychiatric disorders in later life; thus, the dynamic expression and function of P2 receptors on gut epithelial cells during disease processes indicate a novel avenue for the evaluation of disease progression and for the discovery of related therapeutic compounds.

The P2X7 receptor: a new therapeutic target in Alzheimer's disease.

INTRODUCTION: Alzheimer's disease (AD) is a neurodegenerative illness with genetic risk as an etiological factor in a subset of cases. In AD with autosomal dominant inheritance, the extracellular ß-amyloid (Aß) aggregates and intracellular neurofibrillary tangles which consist of hyperphosphorylated tau, appear to be involved in the neuronal damage; however, other forms of AD may have a polygenetic causality. Microglial cells orchestrate pathophysiological events responsible for neuronal damage in AD. They surround Aß aggregates and the stimulation of microglial P2X7 receptors (P2X7Rs) by high local concentrations of ATP which originates from damaged CNS cells, results in degeneration of nearby neurons. Areas covered: We discuss the pathogenesis of Alzheimer's disease, the role of P2X7 receptors and their potential as therapeutic targets. We also address the fundamental hurdles in the development of new therapeutic strategies for Alzheimer's disease. Expert opinion: There are many difficulties associated with the development of efficient pharmacological strategies for AD; the lack of good animal and cellular models for this illness is a key obstacle. None of the pharmacological strategies developed so far have led to an improvement of the treatment of AD. Hence, the consideration of blood-brain barrier-permeable P2X7R antagonists as possible therapeutic agents in AD is a must.

18F-labeled ethisterone derivative for progesterone receptor targeted PET imaging of breast cancer.

PURPOSE: A novel radiolabeled probe 1­(17­[18F]fluoro­3,6,9,12,15­pentaoxaheptadecyl­1H­1,2,3­triazole testosterone ([18F]FPTT) was synthesized and evaluated for PET imaging of progesterone receptor (PR)-positive breast cancer. METHODS: The ethinyl group of ethisterone, a PR targeting pharmacophore, was coupled with azide modified PEG-OTs by click chemistry to obtain the labeling precursor. The final [18F]FPTT was synthesized by a one-step nucleophilic substitution reaction with 18F. The in vitro stabilities of [18F]FPTT in saline or rat serum were determined after 2 h incubation. Then the in vitro cell binding, ex vivo biodistribution and in vivo imaging of [18F]FPTT were further investigated to evaluate the PR targeting ability and feasibility for the diagnosis of PR-positive breast cancer with PET imaging. RESULTS: [18F]FPTT was obtained in high decay-corrected radiochemical yield (78 ±â€¯9%) at the end of synthesis. It had high radiochemical purity (>98%) after HPLC purification and good in vitro stability. The molar activity of [18F]FPTT was calculated as 17 GBq/µmol. The microPET imaging of [18F]FPTT in tumor-bearing mice showed much higher tumor uptake in PR-positive MCF-7 tumor (3.9 ±â€¯0.20%ID/g) than that of PR-negative MDA-MB-231 tumor (1.3 ±â€¯0.08%ID/g). The high MCF-7 tumor uptake could be specifically inhibited by blocking with ethisterone (1.3 ±â€¯0.11%ID/g) or [19F]FPTT (2.20 ±â€¯0.17%ID/g), respectively. The biodistribution in estrogen-primed female SD rats of [18F]FPTT showed high uterus and ovary uptakes (8.31 ±â€¯1.74%ID/g and 3.79 ±â€¯0.82%ID/g at 1 h post-injection). The specific uptakes of uterus and ovary in normal rats were 3.52 ±â€¯0.29%ID/g and 3.22 ±â€¯0.50%ID/g respectively and could be inhibited by co-injecting of ethisterone. CONCLUSION: A novel [18F]FPTT probe based on ethisterone modification could be a potential diagnostic agent for PR-positive breast cancer.

Desmin- and vimentin-mediated hepatic stellate cell-targeting radiotracer 99mTc-GlcNAc-PEI for liver fibrosis imaging with SPECT.

Extracellular matrix (ECM) accumulation in liver fibrosis is caused by the activation of hepatic stellate cells (HSCs). The goal of this study was to develop a 99mTc-labeled N-acetylglucosamine (GlcNAc) that specifically interacts with desmin and vimentin expressed on activated HSCs to monitor the progression and prognosis of liver fibrosis using single-photon emission computed tomography (SPECT) imaging. Methods: GlcNAc-conjugated polyethylenimine (PEI) was first prepared and radiolabeled with 99mTc. Noninvasive SPECT imaging with 99mTc-GlcNAc-PEI was used to assess liver fibrosis in a carbon tetrachloride (CCl4) mouse model. The liver uptake value (LUV) of 99mTc-GlcNAc-PEI was measured by drawing the region of interest (ROI) of the whole liver as previously suggested. The LUV of the CCl4 groups was compared with that of the olive oil group. Next, we estimated the correlation between the results of SPECT imaging and physiological indexes. After treatment with clodronate liposome, the LUV of 99mTc-GlcNAc-PEI in fibrotic mice was compared with that in control mice. Results:99mTc-GlcNAc-PEI is a hydrophilic compound with high radiochemical purity (>98%) and good stability. It could specifically target desmin and vimentin on the surface of activated HSCs with high affinity (the Kd values were 53.75 ± 9.50 nM and 20.98 ± 3.56 nM, respectively). The LUV of 99mTc-GlcNAc-PEI was significantly different between the CCl4 and control groups as early as 4 weeks of CCl4 administration (3.30 ± 0.160 vs 2.34 ± 0.114%/cc; P ˂ 0.05). There was a strong correlation between the LUV and Sirius Red quantification (R = 0.92, P ˂ 0.001). Compared with control, clodronate liposome treatment reduced the LUV of 99mTc-GlcNAc-PEI (4.62 ± 0.352 vs 2.133 ± 0.414%/cc; P ˂ 0.05). Conclusion:99mTc-GlcNAc-PEI SPECT/CT was useful in assessing liver fibrosis and monitoring the treatment response.