Synaptic vesicle protein 2, A new neuroendocrine cell marker

Synaptic vesicle glycoprotein 2 enables viable aneuploidy following centrosome amplification

Amplified centrosome number causes genomic instability, most severely through division into more than two aneuploid daughter cells (multipolar mitosis). Several mechanisms that suppress multipolar division have been uncovered, yet mechanisms that favor viable multipolar division are poorly understood. To uncover factors that promote viability in cells with frequent centrosome amplification and multipolar division, we conducted an unbiased Drosophila genetic screen. In 642 mutagenized lines, we exploited the ability of intestinal papillar cells to form and function despite multipolar divisions. Our top hit is an unnamed gene, CG3168 . We name this gene synaptic vesicle glycoprotein 2 , reflecting homology to human Synaptic Vesicle Glycoprotein 2 (SV2) proteins. GFP-tagged SV2 localizes to the plasma membrane. In cells with amplified centrosomes, SV2 positions membrane-adjacent centrosomes, which prevents severe errors in chromosome alignment and segregation. Our results uncover membrane-based multipolar division regulation and reveal a novel vulnerability in cells with common cancer properties.

Synaptic Vesicle Glycoprotein 2A Knockout in Parvalbumin and Somatostatin Interneurons Drives Seizures in the Postnatal Mouse Brain

Synaptic vesicle glycoprotein 2A (SV2A) is a presynaptic protein targeted by the antiseizure drug levetiracetam. One or more of the three SV2 genes is expressed in all neurons and is essential to normal neurotransmission. Loss of SV2A results in a seizure phenotype in mice and mutations in humans are also linked to congenital seizures. How SV2A action impacts the epileptic phenotype remains unclear, especially among the diverse neuronal populations that regulate network excitability. This study explored how brain structure and function are affected by SV2A conditional knock-out (SV2A-cKO) in specific neural cell subtypes. We show that SV2A-cKO in all neurons of the postnatal brain triggers lethal seizures, suggesting that the seizures observed in earlier knock-out models were not due to aberrant brain development. Similar lethal seizures are detected in mice in which the loss of SV2A is limited to GABAergic neurons, whereas loss in excitatory neurons produces no noticeable phenotype. No apparent gender difference was ever observed. Further investigation revealed that SV2A-cKO in different GABAergic interneuron populations induces seizure, with variable timescales and severity. Most notably SV2A-cKO in parvalbumin interneurons (PV+) leads to lethal seizures in young animals, while SV2A-cKO in somatostatin (SST) inhibitory neurons results in seizures that were scarcely observed only in adult mice. These results support the crucial role SV2A plays in PV and SST interneurons and suggest that the action of levetiracetam may be due largely to effects on a subset of GABAergic interneurons.

Evaluation of Small-Molecule Candidates as Modulators of M-Type K+ Currents: Impacts on Current Amplitude, Gating, and Voltage-Dependent Hysteresis

The core subunits of the KV7.2, KV7.3, and KV7.5 channels, encoded by the KCNQ2, KCNQ3, and KCNQ5 genes, are expressed across various cell types and play a key role in generating the M-type K+ current (IK(M)). This current is characterized by an activation threshold at low voltages and displays slow activation and deactivation kinetics. Variations in the amplitude and gating kinetics of IK(M) can significantly influence membrane excitability. Notably, IK(M) demonstrates distinct voltage-dependent hysteresis when subjected to prolonged isosceles-triangular ramp pulses. In this review, we explore various small-molecule modulators that can either inhibit or enhance the amplitude of IK(M), along with their perturbations on its gating kinetics and voltage-dependent hysteresis. The inhibitors of IK(M) highlighted here include bisoprolol, brivaracetam, cannabidiol, nalbuphine, phenobarbital, and remdesivir. Conversely, compounds such as flupirtine, kynurenic acid, naringenin, QO-58, and solifenacin have been shown to enhance IK(M). These modulators show potential as pharmacological or therapeutic strategies for treating certain disorders linked to gain-of-function or loss-of-function mutations in M-type K+ (KV7x or KCNQx) channels.

GMP-compliant automated radiosynthesis of [18F] SynVesT-1 for PET imaging of synaptic vesicle glycoprotein 2 A (SV2A)

BACKGROUND

A novel positron emission tomography (PET) imaging tracer, [18F] SynVesT-1, targeting synaptic vesicle glycoprotein 2 (SV2A), has been developed to meet clinical demand. Utilizing the Trasis AllinOne-36 (AIO) module, we've automated synthesis to Good Manufacturing Practice (GMP) standards, ensuring sterile, pyrogen-free production. The fully GMP-compliant robust synthesis of [18F] SynVesT-1 boosting reliability and introducing a significant degree of simplicity and its comprehensive validation for routine human use.

RESULTS

[18F] SynVesT-1 was synthesized by small modifications to the original [18F] SynVesT-1 synthesis protocol to better fit AIO module using an in-house designed cassette and sequence. With a relatively small precursor load of 5 mg, [18F] SynVesT-1 was obtained with consistently high radiochemical yields (RCY) of 20.6 ± 1.2% (the decay-corrected RCY, n = 3) at end of synthesis. Each of the final formulated batches demonstrated radiochemical purity (RCP) and enantiomeric purity surpassing 99%. The entire synthesis process was completed within a timeframe of 80 min (75 ± 3.1 min, n = 3), saves 11 min compared to reported GMP automated synthesis procedures. The in-human PET imaging of total body PET/CT and time-of-flight (TOF) PET/MR showed that [18F] SynVesT-1 is an excellent tracer for SV2A. It is advantageous for decentralized promotion and application in multi-center studies.

CONCLUSION

The use of AIO synthesizer maintains high production yields and increases reliability, reduces production time and allows rapid training of production staff. Besides, the as-prepared [18F] SynVesT-1 displays excellent in vivo binding properties in humans and holds great potential for the imaging and quantification of synaptic density in vivo.

SV2A PET imaging in human neurodegenerative diseases

This manuscript presents a thorough review of synaptic vesicle glycoprotein 2A (SV2A) as a biomarker for synaptic integrity using Positron Emission Tomography (PET) in neurodegenerative diseases. Synaptic pathology, characterized by synaptic loss, has been linked to various brain diseases. Therefore, there is a need for a minimally invasive approach to measuring synaptic density in living human patients. Several radiotracers targeting synaptic vesicle protein 2A (SV2A) have been created and effectively adapted for use in human subjects through PET scans. SV2A is an integral glycoprotein found in the membranes of synaptic vesicles in all synaptic terminals and is widely distributed throughout the brain. The review delves into the development of SV2A-specific PET radiotracers, highlighting their advancements and limitations in neurodegenerative diseases. Among these tracers, 11C-UCB-J is the most used so far. We summarize and discuss an increasing body of research that compares measurements of synaptic density using SV2A PET with other established indicators of neurodegenerative diseases, including cognitive performance and radiological findings, thus providing a comprehensive analysis of SV2A's effectiveness and reliability as a diagnostic tool in contrast to traditional markers. Although the literature overall suggests the promise of SV2A as a diagnostic and therapeutic monitoring tool, uncertainties persist regarding the superiority of SV2A as a biomarker compared to other available markers. The review also underscores the paucity of studies characterizing SV2A distribution and loss in human brain tissue from patients with neurodegenerative diseases, emphasizing the need to generate quantitative neuropathological maps of SV2A density in cases with neurodegenerative diseases to fully harness the potential of SV2A PET imaging in clinical settings. We conclude by outlining future research directions, stressing the importance of integrating SV2A PET imaging with other biomarkers and clinical assessments and the need for longitudinal studies to track SV2A changes throughout neurodegenerative disease progression, which could lead to breakthroughs in early diagnosis and the evaluation of new treatments.

Frenemies in the Microenvironment: Harnessing Mast Cells for Cancer Immunotherapy

Tumor development, progression, and resistance to therapies are influenced by the interactions between tumor cells and the surrounding microenvironment, comprising fibroblasts, immune cells, and extracellular matrix proteins. In this context, mast cells (MCs) have recently emerged as important players. Yet, their role is still controversial, as MCs can exert pro- or anti-tumor functions in different tumor types depending on their location within or around the tumor mass and their interaction with other components of the tumor microenvironment. In this review, we describe the main aspects of MC biology and the different contribution of MCs in promoting or inhibiting cancer growth. We then discuss possible therapeutic strategies aimed at targeting MCs for cancer immunotherapy, which include: (1) targeting c-Kit signaling; (2) stabilizing MC degranulation; (3) triggering activating/inhibiting receptors; (4) modulating MC recruitment; (5) harnessing MC mediators; (6) adoptive transferring of MCs. Such strategies should aim to either restrain or sustain MC activity according to specific contexts. Further investigation would allow us to better dissect the multifaceted roles of MCs in cancer and tailor novel approaches for an "MC-guided" personalized medicine to be used in combination with conventional anti-cancer therapies.

Synaptic Vesicle Glycoprotein 2A: Features and Functions

In recent years, the field of neuroimaging dramatically moved forward by means of the expeditious development of specific radioligands of novel targets. Among these targets, the synaptic vesicle glycoprotein 2A (SV2A) is a transmembrane protein of synaptic vesicles, present in all synaptic terminals, irrespective of neurotransmitter content. It is involved in key functions of neurons, focused on the regulation of neurotransmitter release. The ubiquitous expression in gray matter regions of the brain is the basis of its candidacy as a marker of synaptic density. Following the development of molecules derived from the structure of the anti-epileptic drug levetiracetam, which selectively binds to SV2A, several radiolabeled markers have been synthetized to allow the study of SV2A distribution with positron emission tomography (PET). These radioligands permit the evaluation of in vivo changes of SV2A distribution held to be a potential measure of synaptic density in physiological and pathological conditions. The use of SV2A as a biomarker of synaptic density raises important questions. Despite numerous studies over the last decades, the biological function and the expressional properties of SV2A remain poorly understood. Some functions of SV2A were claimed, but have not been fully elucidated. While the expression of SV2A is ubiquitous, stronger associations between SV2A and Υ amino butyric acid (GABA)-ergic rather than glutamatergic synapses were observed in some brain structures. A further issue is the unclear interaction between SV2A and its tracers, which reflects a need to clarify what really is detected with neuroimaging tools. Here, we summarize the current knowledge of the SV2A protein and we discuss uncertain aspects of SV2A biology and physiology. As SV2A expression is ubiquitous, but likely more strongly related to a certain type of neurotransmission in particular circumstances, a more extensive knowledge of the protein would greatly facilitate the analysis and interpretation of neuroimaging results by allowing the evaluation not only of an increase or decrease of the protein level, but also of the type of neurotransmission involved.

Neuron-recognizable characteristics of peptides recombined using a neuronal binding domain of botulinum neurotoxin

Recombinant peptides were designed using the C-terminal domain (receptor binding domain, RBD) and its subdomain (peptide A2) of a heavy chain of botulinum neurotoxin A-type 1 (BoNT/A1), which can bind to the luminal domain of synaptic vesicle glycoprotein 2C (SV2C-LD). Peptide A2- or RBD-containing recombinant peptides linked to an enhanced green fluorescence protein (EGFP) were prepared by expression in Escherichia coli. A pull-down assay using SV2C-LD-covered resins showed that the recombinant peptides for CDC297 BoNT/A1, referred to EGFP-A2' and EGFP-RBD', exhibited ≥ 2.0-times stronger binding affinity to SV2C-LD than those for the wild-type BoNT/A1. Using bio-layer interferometry, an equilibrium dissociation rate constant (K_D) of EGFP-RBD' to SV2C-LD was determined to be 5.45 μM, which is 33.87- and 15.67-times smaller than the K_D values for EGFP and EGFP-A2', respectively. Based on confocal laser fluorescence micrometric analysis, the adsorption/absorption of EGFP-RBD' to/in differentiated PC-12 cells was 2.49- and 1.29-times faster than those of EGFP and EGFP-A2', respectively. Consequently, the recombinant peptides acquired reasonable neuron-specific binding/internalizing ability through the recruitment of RBD'. In conclusion, RBDs of BoNTs are versatile protein domains that can be used to mark neural systems and treat a range of disorders in neural systems.

Defective Neuronal Positioning Correlates With Aberrant Motor Circuit Function in Zebrafish

Precise positioning of neurons resulting from cell division and migration during development is critical for normal brain function. Disruption of neuronal migration can cause a myriad of neurological disorders. To investigate the functional consequences of defective neuronal positioning on circuit function, we studied a zebrafish frizzled3a (fzd3a) loss-of-function mutant off-limits (olt) where the facial branchiomotor (FBM) neurons fail to migrate out of their birthplace. A jaw movement assay, which measures the opening of the zebrafish jaw (gape), showed that the frequency of gape events, but not their amplitude, was decreased in olt mutants. Consistent with this, a larval feeding assay revealed decreased food intake in olt mutants, indicating that the FBM circuit in mutants generates defective functional outputs. We tested various mechanisms that could generate defective functional outputs in mutants. While fzd3a is ubiquitously expressed in neural and non-neural tissues, jaw cartilage and muscle developed normally in olt mutants, and muscle function also appeared to be unaffected. Although FBM neurons were mispositioned in olt mutants, axon pathfinding to jaw muscles was unaffected. Moreover, neuromuscular junctions established by FBM neurons on jaw muscles were similar between wildtype siblings and olt mutants. Interestingly, motor axons innervating the interhyoideus jaw muscle were frequently defasciculated in olt mutants. Furthermore, GCaMP imaging revealed that mutant FBM neurons were less active than their wildtype counterparts. These data show that aberrant positioning of FBM neurons in olt mutants is correlated with subtle defects in fasciculation and neuronal activity, potentially generating defective functional outputs.

Overexpression of ODF1 in Gastrointestinal Tract Neuroendocrine Neoplasms: a Novel Potential Immunohistochemical Biomarker for Well-differentiated Neuroendocrine Tumors

Gastrointestinal tract neuroendocrine neoplasms (NENs) are a group of rare heterogeneous tumors with different prognoses. The 2019 WHO classification of digestive system tumors defines the classification of NENs as neuroendocrine tumors (NETs G1-G3) and neuroendocrine carcinomas (NECs). We investigated outer dense fiber of sperm tails 1 (ODF1) expression in 137 gastrointestinal tract NENs including 53 NETs G1, 29 NETs G2, 3 NETs G3, and 52 NECs. Twenty adenocarcinomas and 6 squamous cell carcinomas also were included in the study. The results showed that ODF1 was positive in 83 of 85 (97.6%) primary gastrointestinal tract NETs, including 9 of 10 (90%) gastric, 19 of 19 (100%) small bowel, 10 of 11 (90.9%) colorectal, and 45 of 45 (100%) appendiceal neoplasms. There was a significantly statistical difference in the rates of ODF1 positivity in NETs (83/85, 97.6%) vs NECs (25/52, 48.1%, P < 0.001). ODF1 showed diffuse staining in NETs G1 (53/53, 100%) and NETs G2 (28/29, 96.6%), > 50% staining in NETs G3 (2/3, 66.7%), and focal staining (< 50%) in NECs (23/52, 44.2%) but 2 cases (2/52) showed > 50% staining. ODF1 showed no expression in all 20 adenocarcinomas and 6 squamous cell carcinomas. In conclusion, ODF1 was firstly identified as a novel marker for NENs, especially for NETs in the gastrointestinal tract. The expression mechanism and clinical significance of ODF1 in NENs needed further study.

Undesirable Status of Prostate Cancer Cells after Intensive Inhibition of AR Signaling: Post-AR Era of CRPC Treatment

Recent advances in prostate cancer (PC) research unveiled real androgen receptor (AR) functions in castration-resistant PC (CRPC). Moreover, AR still accelerates PC cell proliferation via the activation of several mechanisms (e.g., mutation, variants, and amplifications in CRPC). New-generation AR signaling-targeted agents, inhibiting extremely the activity of AR, were developed based on these incontrovertible mechanisms of AR-induced CRPC progression. However, long-term administration of AR signaling-targeted agents subsequently induces the major problem that AR (complete)-independent CRPC cells present neither AR nor prostate-specific antigen, including neuroendocrine differentiation as a subtype of AR-independent CRPC. Moreover, there are few treatments effective for AR-independent CRPC with solid evidence. This study focuses on the transformation mechanisms of AR-independent from AR-dependent CRPC cells and potential treatment strategy for AR-independent CRPC and discusses them based on a review of basic and clinical literature.

The Integrated Effects of Brivaracetam, a Selective Analog of Levetiracetam, on Ionic Currents and Neuronal Excitability

Brivaracetam (BRV) is recognized as a novel third-generation antiepileptic drug approved for the treatment of epilepsy. Emerging evidence has demonstrated that it has potentially better efficacy and tolerability than its analog, Levetiracetam (LEV). This, however, cannot be explained by their common synaptic vesicle-binding mechanism. Whether BRV can affect different ionic currents and concert these effects to alter neuronal excitability remains unclear. With the aid of patch clamp technology, we found that BRV concentration dependently inhibited the depolarization-induced M-type K+ current (IK(M)), decreased the delayed-rectifier K+ current (IK(DR)), and decreased the hyperpolarization-activated cation current in GH3 neurons. However, it had a concentration-dependent inhibition on voltage-gated Na+ current (INa). Under an inside-out patch configuration, a bath application of BRV increased the open probability of large-conductance Ca2+-activated K+ channels. Furthermore, in mHippoE-14 hippocampal neurons, the whole-cell INa was effectively depressed by BRV. In simulated modeling of hippocampal neurons, BRV was observed to reduce the firing of the action potentials (APs) concurrently with decreases in the AP amplitude. In animal models, BRV ameliorated acute seizures in both OD-1 and lithium-pilocarpine epilepsy models. However, LEV had effects in the latter only. Collectively, our study demonstrated BRV's multiple ionic mechanism in electrically excitable cells and a potential concerted effect on neuronal excitability and hyperexcitability disorders.

Repurposing of the Antiepileptic Drug Levetiracetam to Restrain Neuroendocrine Prostate Cancer and Inhibit Mast Cell Support to Adenocarcinoma

A relevant fraction of castration-resistant prostate cancers (CRPC) evolve into fatal neuroendocrine (NEPC) tumors in resistance to androgen deprivation and/or inhibitors of androgen receptor pathway. Therefore, effective drugs against both CRPC and NEPC are needed. We have previously described a dual role of mast cells (MCs) in prostate cancer, being capable to promote adenocarcinoma but also to restrain NEPC. This finding suggests that a molecule targeting both MCs and NEPC cells could be effective against prostate cancer. Using an in silico drug repurposing approach, here we identify the antiepileptic drug levetiracetam as a potential candidate for this purpose. We found that the protein target of levetiracetam, SV2A, is highly expressed by both NEPC cells and MCs infiltrating prostate adenocarcinoma, while it is low or negligible in adenocarcinoma cells. In vitro, levetiracetam inhibited the proliferation of NEPC cells and the degranulation of MCs. In mice bearing subcutaneous tumors levetiracetam was partially active on both NEPC and adenocarcinoma, the latter effect due to the inhibition of MMP9 release by MCs. Notably, in TRansgenic Adenocarcinoma of the Mouse Prostate (TRAMP) mice subjected to surgical castration to mimic androgen deprivation therapy, levetiracetam reduced onset and frequency of both high grade prostatic intraepithelial neoplasia, adenocarcinoma and NEPC, thus increasing the number of cured mice showing only signs of tumor regression. Our results demonstrate that levetiracetam can directly restrain NEPC development after androgen deprivation, and that it can also block adenocarcinoma progression through the inhibition of some MCs functions. These findings open the possibility of further testing levetiracetam for the therapy of prostate cancer or of MC-mediated diseases.

[Neuroendocrine markers in parathyroid tumors]

The parathyroid glands (PTGs) are a key regulator of calcium and phosphorus metabolism in the human body. In terms of their, morphological and immunophenotypic characteristics, PTGs are neuroendocrine organs, and their neoplasms are neuroendocrine tumors. These neoplasms include adenoma and cancer; in addition, glandular hyperplasia may develop, which is most characteristic of multiple endocrine neoplasia (MEN1, MEN2a, and MEN4) syndromes. The morphological characteristics of pathologically altered PTGs in MEN syndromes are variable. The analysis and generalization of knowledge about the features and expression of various immunohistochemical markers in PTG tissue in health and in diseases are useful in the practical work of not only pathologists, but also clinicians of various specialties.

Non-toxic fragment of botulinum neurotoxin type A and monomethyl auristatin E conjugate for targeted therapy for neuroendocrine tumors

Surgical resection is the only cure for neuroendocrine tumors (NETs). However, widespread metastases have already occured by the time of initial diagnosis in many cases making complete surgical removal impossible. We developed a recombinant heavy-chain receptor binding domain (rHCR) of botulinum neurotoxin type A that can specifically target synaptic vesicle 2 (SV2), a surface receptor abundantly expressed in multiple neuroendocrine tumors. Expression of neuroendocrine differentiation markers chromogranin A (CgA) and achaete-scute complex 1 (ASCL1) were signficantly reduced when treated with rHCR. rHCR conjugated to the antimitotic agent monomethyl auristatin E (MMAE) significantly suppressed proliferation of pancreatic carcinoid (BON) and medullary thyroid cancer cells (MZ) at concentrations of 500 and 300 nM respectively, while no growth suppression was observed in pulmonary fibroblasts and cortical neuron control cell lines. In vivo, rHCR-MMAE significantly reduced tumor volume in mouse xenografts with no observed adverse effects. These data suggest recombinant HCR (rHCR) of BoNT/A preferentially targets neuroendocrine cancer without the neurotoxicity of the full BoNT/A and that SV2 is a specific and promising target for delivering drugs to neuroendocrine tumors.

Brivaracetam attenuates pain behaviors in a murine model of neuropathic pain

Background

The antiseizure racetams may provide novel molecular insights into neuropathic pain due to their unique mechanism involving synaptic vesicle glycoprotein 2A. Anti-allodynic effects of levetiracetam have been shown in animal models of neuropathic pain. Here, we studied the effect of brivaracetam, which binds to synaptic vesicle glycoprotein 2A with 20-fold greater affinity, and has fewer off-target effects.

Methods

Mice underwent unilateral sciatic nerve cuffing and were evaluated for mechanical sensitivity using von Frey filaments. Pain behaviors were assessed with prophylactic treatment using levetiracetam (100 or 10 mg/kg) or brivaracetam (10 or 1 mg/kg) beginning after surgery and continuing for 21 days, or with therapeutic treatment using brivaracetam (10 or 1 mg/kg) beginning on day 14, after allodynia was established, and continuing for 28 or 63 days. Spinal cord tissues from the prophylaxis experiment with10 mg/kg brivaracetam were examined for neuroinflammation (Iba1 and tumor necrosis factor), T-lymphocyte (CD3) infiltration, and synaptic vesicle glycoprotein 2A expression.

Results

When used prophylactically, levetiracetam, 100 mg/kg, and brivaracetam, 10 mg/kg, prevented the development of allodynia, with lower doses of each being less effective. When used therapeutically, brivaracetam extinguished allodynia, requiring 10 days with 10 mg/kg, and six weeks with 1 mg/kg. Brivaracetam was associated with reduced neuroinflammation and reduced T-lymphocyte infiltration in the dorsal horn. After sciatic nerve cuffing, synaptic vesicle glycoprotein 2A expression was identified in neurons, activated astrocytes, microglia/macrophages, and T lymphocytes in the dorsal horn.

Conclusion

Synaptic vesicle glycoprotein 2A may represent a novel target for neuropathic pain. Brivaracetam may warrant study in humans with neuropathic pain due to peripheral nerve injury.

Cho W, Soleimanpour S. Bacteriotherapy in Breast Cancer

Breast cancer is the second most common cause of cancer-related mortality among women around the world. Conventional treatments in the fight against breast cancer, such as chemotherapy, are being challenged regarding their effectiveness. Thus, strategies for the treatment of breast cancer need to be continuously refined to achieve a better patient outcome. We know that a number of bacteria are pathogenic and some are even associated with tumor development, however, recent studies have demonstrated interesting results suggesting some bacteria may have potential for cancer therapy. Therefore, the therapeutic role of bacteria has aroused attention in medical and pharmaceutical studies. Furthermore, genetic engineering has been used in bacterial therapy and may led to greater efficacy with few side effects. Some genetically modified non-pathogenic bacterial species are more successful due to their selectivity for cancer cells but with low toxicity for normal cells. Some live, attenuated, or genetically modified bacterias are capable to multiply in tumors and inhibit their growth. This article aims to review the role of bacteria and their products including bacterial peptides, bacteriocins, and toxins for the treatment of breast cancer.

The Synaptic Vesicle Glycoprotein 2: Structure, Function, and Disease Relevance

The synaptic vesicle glycoprotein 2 (SV2) family is comprised of three paralogues: SV2A, SV2B, and SV2C. In vertebrates, SV2s are 12-transmembrane proteins present on every secretory vesicle, including synaptic vesicles, and are critical to neurotransmission. Structural and functional studies suggest that SV2 proteins may play several roles to promote proper vesicular function. Among these roles are their potential to stabilize the transmitter content of vesicles, to maintain and orient the releasable pool of vesicles, and to regulate vesicular calcium sensitivity to ensure efficient, coordinated release of the transmitter. The SV2 family is highly relevant to human health in a number of ways. First, SV2A plays a role in neuronal excitability and as such is the specific target for the antiepileptic drug levetiracetam. SV2 proteins also act as the target by which potent neurotoxins, particularly botulinum, gain access to neurons and exert their toxicity. Both SV2B and SV2C are increasingly implicated in diseases such as Alzheimer's disease and Parkinson's disease. Interestingly, despite decades of intensive research, their exact function remains elusive. Thus, SV2 proteins are intriguing in their potentially diverse roles within the presynaptic terminal, and several recent developments have enhanced our understanding and appreciation of the protein family. Here, we review the structure and function of SV2 proteins as well as their relevance to disease and therapeutic development.

Synaptic Vesicle Protein 2 and Vesicular Monoamine Transporter 1 and 2 Are Expressed in Neuroblastoma

Neuroblastoma (NB), the most common extracranial cancer in childhood, exhibits neuroendocrine (NE) differentiation. Two well-established NE markers, chromogranin A (CgA) and synaptophysin (syn), are used in the histopathological diagnostics. Our aims were to explore if the NE markers synaptic vesicle protein 2 (SV2) and vesicular monoamine transporter 1 (VMAT1) and 2 (VMAT2) also are expressed in human NB and if so, evaluate their usefulness in NB histopathological diagnostics. Tumor specimens from 21 NB patients, before and/or after chemotherapy, were immunostained for CgA, syn, SV2, VMAT1, and VMAT2. Clinical data was extracted from patients' records. SV2 was highly expressed in NB, as was CgA while syn was less frequently expressed compared to the other two. Both VMATs were expressed in several NB, VMAT2 in more cases than VMAT1 and its expression was similar to syn. Chemotherapy did not affect the immunoreactivity in an obvious way. SV2 was highly expressed in NB and can thus be useful marker in NB diagnostics. VMAT1 and VMAT2 were also expressed in NB but similar to syn less reliable as tumor markers.

Synaptic vesicle protein 2: A multi-faceted regulator of secretion

Synaptic Vesicle Protein 2 (SV2) comprises a recently evolved family of proteins unique to secretory vesicles that undergo calcium-regulated exocytosis. In this review we consider SV2s' structural features, evolution, and function and discuss its therapeutic potential as the receptors for an expanding class of drugs used to treat epilepsy and cognitive decline.

Intrinsic FGFR2 and Ectopic FGFR1 Signaling in the Prostate and Prostate Cancer

Advanced castrate-resistant prostate cancer (CRPC) is a poorly prognostic disease currently lacking effective cure. Understanding the molecular mechanism that underlies the initiation and progression of CRPC will provide new strategies for treating this deadly disease. One candidate target is the fibroblast growth factor (FGF) signaling axis. Loss of the intrinsic FGF7/FGF10-type 2 FGF receptor (FGFR2) pathway and gain of the ectopic type 1 FGF receptor (FGFR1) pathway are associated with the progression to malignancy in prostate cancer (PCa) and many other epithelial originating lesions. Although FGFR1 and FGFR2 share similar amino acid sequences and structural domains, the two transmembrane tyrosine kinases elicit distinctive, even sometime opposite signals in cells. Recent studies have revealed that the ectopic FGFR1 signaling pathway contributes to PCa progression via multiple mechanisms, including promoting tumor angiogenesis, reprogramming cancer cell metabolism, and potentiating inflammation in the tumor microenvironment. Thus, suppression of FGFR1 signaling can be an effective novel strategy to treat CRPC.

Immunohistochemical Biomarkers of Gastrointestinal, Pancreatic, Pulmonary, and Thymic Neuroendocrine Neoplasms

Neuroendocrine neoplasms (NENs) are a heterogeneous group of epithelial neoplastic proliferations that irrespective of their primary site share features of neural and endocrine differentiation including the presence of secretory granules, synaptic-like vesicles, and the ability to produce amine and/or peptide hormones. NENs encompass a wide spectrum of neoplasms ranging from well-differentiated indolent tumors to highly aggressive poorly differentiated neuroendocrine carcinomas. Most cases arise in the digestive system and in thoracic organs, i.e., the lung and thymus. A correct diagnostic approach is crucial for the management of patients with both digestive and thoracic NENs, because their high clinical and biological heterogeneity is related to their prognosis and response to therapy. In this context, immunohistochemistry represents an indispensable diagnostic tool that pathologists need to use for the correct diagnosis and classification of such neoplasms. In addition, immunohistochemistry is also useful in identifying prognostic and theranostic markers. In the present article, the authors will review the role of immunohistochemistry in the routine workup of digestive and thoracic NENs.

Evaluation of PET Brain Radioligands for Imaging Pancreatic β-Cell Mass: Potential Utility of 11C-(+)-PHNO

Type 1 diabetes mellitus (T1DM) is characterized by a loss of β-cells in the islets of Langerhans of the pancreas and subsequent deficient insulin secretion in response to hyperglycemia. Development of an in vivo test to measure β-cell mass (BCM) would greatly enhance the ability to track diabetes therapies. β-cells and neurologic tissues have common cellular receptors and transporters, therefore, we screened brain radioligands for their ability to identify β-cells. Methods: We examined a β-cell gene atlas for endocrine pancreas receptor targets and cross-referenced these targets with brain radioligands that were available at our institution. Twelve healthy control subjects and 2 T1DM subjects underwent dynamic PET/CT scans with 6 tracers. Results: The D₂/D₃ receptor agonist radioligand ¹¹C-(+)-4-propyl-9-hydroxynaphthoxazine (PHNO) was the only radioligand to demonstrate sustained uptake in the pancreas with high contrast versus abdominal organs such as the kidneys, liver, and spleen, based on the first 30 min of data. Mean SUV from 20 to 30 min demonstrated high uptake of ¹¹C-(+)-PHNO in healthy controls (SUV, 13.8) with a 71% reduction in a T1DM subject with undetectable levels of C-peptide (SUV, 4.0) and a 20% reduction in a T1DM subject with fasting C-peptide level of 0.38 ng/mL (SUV, 11.0). SUV in abdominal organs outside the pancreas did not show measurable differences between the control and T1DM subjects, suggesting that the changes in SUV of ¹¹C-(+)-PHNO may be specific to changes in the pancreas between healthy controls and T1DM subjects. When D₃ and D₂ antagonists were used in nonhuman primates, specific pancreatic binding (SUVR-1) of ¹¹C-PHNO was reduced by 57% and 38%, respectively. Conclusion:¹¹C-(+)-PHNO is a potential marker of BCM, with 2:1 binding of D₃ receptors over D₂ receptors. Further in vitro and in vivo studies to establish D₂/D₃ receptor specificity to β-cells is warranted to characterize ¹¹C-(+)-PHNO as a candidate for clinical measurement of BCM in healthy control and diabetic subjects.

A new role for the P2Y-like GPR17 receptor in the modulation of multipotency of oligodendrocyte precursor cells in vitro

Oligodendrocyte precursor cells (OPCs, also called NG2 cells) are scattered throughout brain parenchyma, where they function as a reservoir to replace lost or damaged oligodendrocytes, the myelin-forming cells. The hypothesis that, under some circumstances, OPCs can actually behave as multipotent cells, thus generating astrocytes and neurons as well, has arisen from some in vitro and in vivo evidence, but the molecular pathways controlling this alternative fate of OPCs are not fully understood. Their identification would open new opportunities for neuronal replace strategies, by fostering the intrinsic ability of the brain to regenerate. Here, we show that the anti-epileptic epigenetic modulator valproic acid (VPA) can promote the generation of new neurons from NG2⁺ OPCs under neurogenic protocols in vitro, through their initial de-differentiation to a stem cell-like phenotype that then evolves to "hybrid" cell population, showing OPC morphology but expressing the neuronal marker βIII-tubulin and the GPR17 receptor, a key determinant in driving OPC transition towards myelinating oligodendrocytes. Under these conditions, the pharmacological blockade of the P2Y-like receptor GPR17 by cangrelor, a drug recently approved for human use, partially mimics the effects mediated by VPA thus accelerating cells' neurogenic conversion. These data show a co-localization between neuronal markers and GPR17 in vitro, and suggest that, besides its involvement in oligodendrogenesis, GPR17 can drive the fate of neural precursor cells by instructing precursors towards the neuronal lineage. Being a membrane receptor, GPR17 represents an ideal "druggable" target to be exploited for innovative regenerative approaches to acute and chronic brain diseases.

Structural and Functional Interactions between Transient Receptor Potential Vanilloid Subfamily 1 and Botulinum Neurotoxin Serotype A

BACKGROUND

Botulinum neurotoxins are produced by Clostridium botulinum bacteria. There are eight serologically distinct botulinum neurotoxin isoforms (serotypes A-H). Currently, botulinum neurotoxin serotype A (BoNT⁄A) is commonly used for the treatment of many disorders, such as hyperactive musculoskeletal disorders, dystonia, and pain. However, the effectiveness of BoNT⁄A for pain alleviation and the mechanisms that mediate the analgesic effects of BoNT⁄A remain unclear. To define the antinociceptive mechanisms by which BoNT/A functions, the interactions between BoNT⁄A and the transient receptor potential vanilloid subfamily 1 (TRPV1) were investigated using immunofluorescence, co-immunoprecipitation, and western blot analysis in primary mouse embryonic dorsal root ganglion neuronal cultures.

RESULTS

1) Three-week-old cultured dorsal root ganglion neurons highly expressed transient TRPV1, synaptic vesicle 2A (SV2A) and synaptosomal-associated protein 25 (SNAP-25). SV2A and SNAP-25 are the binding receptor and target protein, respectively, of BoNT⁄A. 2) TRPV1 colocalized with both BoNT⁄A and cleaved SNAP-25 when BoNT⁄A was added to dorsal root ganglia neuronal cultures. 3) After 24 hours of BoNT⁄A treatment (1 nmol⁄l), both TRPV1 and BoNT⁄A positive bands were detected in western blots of immunoprecipitated pellets. 4) Blocking TRPV1 with a specific antibody decreased the cleavage of SNAP-25 by BoNT⁄A.

CONCLUSION

BoNT/A interacts with TRPV1 both structurally and functionally in cultured mouse embryonic dorsal root ganglion neurons. These results suggest that an alternative mechanism is used by BoNT⁄A to mediate pain relief.

Botulinum neurotoxin type A inhibits synaptic vesicle 2 expression in breast cancer cell lines

AIM

It is known that botulinum neurotoxin type A (BoNTA) improves some kinds of cancer (e.g. prostate) and that synaptic vesicle glycoprotein 2 (SV2) is the molecular target of this neurotoxin. Besides having potential therapeutic value, this glycoprotein has recently been proposed as a molecular marker for several types of cancer. Although the mechanisms of cancer development and the improvement found with botulinum treatment are not well understood, the formation of the botulinum-SV2 complex may influence the presence and distribution of SV2 and the function of vesicles. To date, there are no reports on the possible effect of botulinum on breast cancer of unknown causes, which have a great impact on women's health. Thus we determined the presence of SV2 in three breast cancer cell lines and the alterations found with botulinum application.

MATERIALS AND METHODS

With and without adding 10 units of botulinum, SV2 protein expression was determined by optical densitometry in T47D, MDA-MB-231 and MDA-MB-453 cell lines and the distribution of SV2 was observed with immunochemistry (hematoxylin staining).

RESULTS

The SV2 protein was abundant in the cancer cells herein tested, and maximally so in T47D. In all three cancer cell lines botulinum diminished SV2 expression, which was found mostly in the cell periphery.

CONCLUSION

SV2 could be a molecular marker in breast cancer. Its expression and distribution is regulated by botulinum, suggesting an interesting control mechanism for SV2 expression and a possible alternative therapy. Further studies are needed in this sense.

Neuroendocrine differentiation of prostate cancer: a review

Neuroendocrine cells are one of the epithelial populations in the prostate. Neuroendocrine differentiation (NED) has been observed in prostate cancer. In addition to small cell neuroendocrine carcinomas and carcinoid tumors of the prostate, prostatic adenocarcinomas may have NED. The incidence and clinical relevance of NED in prostatic adenocarcinoma is not clearly understood because of conflicting results in the reported studies, and evaluation of NED is not routinely performed in clinical practice. This review is an overall synthesis with an aim to develop a more comprehensive understanding and practical approach towards the current knowledge of neuroendocrine differentiation. In this review we are stratifying these lesions into separate subtypes based on histologic parameters such as tumor morphology, neuroendocrine cell density and distribution and clinical parameters. We also want to identify current controversies and confusing issues not totally resolved in this topic for further investigations. Eventually a clearer understanding of this phenomenon and appropriate handling NED in prostate cancer will benefit clinical practice.

The immunohistochemical expression of islet 1 and PAX8 by rectal neuroendocrine tumors should be taken into account in the differential diagnosis of metastatic neuroendocrine tumors of unknown primary origin

Rectal neuroendocrine tumors (NETs) can be classified by histologic pattern and secretory products. Recently, rectal NETs have been noted to exhibit immunohistochemical (IHC) positivity for Islet 1 and PAX8, which are generally considered markers for NETs of pancreatic origin. In this study, we sought to characterize the IHC staining profile of rectal NETs and determine whether there was any correlation between the histologic pattern of rectal NETs and their IHC profile. Fifty-six primary rectal NETs were histologically reviewed and stained with antibodies against Islet 1, PAX8, CDX2, chromogranin A, and synaptophysin. In a subset of 31 cases, immunoreactivity for serotonin, pancreatic polypeptide (PP), and prostatic acid phosphatase (PAP) was also studied. By morphology, the tumors studied included 55 % trabecular, 27 % solid nested, 4 % acinar, and 14 % mixed patterns. Islet 1 was positive in 89 % and PAX8 in 79 % of cases. CDX2 was negative in all 56 cases. Cytoplasmic staining was observed for chromogranin A in 30 % of cases and for synaptophysin in all 56 cases. Cytoplasmic staining for serotonin, PP, and PAP was present in 16, 61, and 97 % of cases, respectively. There was no correlation between histologic pattern and IHC staining pattern with any of the antibodies studied. We have demonstrated that Islet 1 and PAX8 are not entirely specific for NETs of pancreatic origin, as they are expressed in a majority of rectal NETs. Since rectal NETs may show an IHC staining profile which mirrors that of pancreatic NETs (Islet 1 and PAX8-positive, CDX2-negative), a metastatic rectal NET should be considered in the differential diagnosis and ruled out clinically in the work-up of a metastatic NET of unknown primary origin which exhibits this staining profile.

Valproic acid, but not levetiracetam, selectively decreases HDAC7 and HDAC2 expression in human ovarian cancer cells

Histone deacetylases (HDACs) are often overexpressed in cancer cells, leading to altered expression and activity of numerous proteins involved in carcinogenesis. Recent evidence suggests that expression of class I HDACs is increased in ovarian carcinomas and plays a significant role in carcinogenesis and resistance to chemotherapeutic agents. Two compounds, valproic acid (VPA) and levetiracetam (LEV), exhibit HDAC inhibitor (HDACI) activity in various cell types, but data concerning their activity in ovarian cancer are lacking. Here we compared the effects of VPA and LEV as HDACIs, using a human ovarian cancer cell line, OVCAR-3. Cells were cultured with VPA or LEV at concentrations between 1 and 10 mM for 1-24h. HDAC activity was determined by fluorometric assay and confirmed by western blotting. Expression of HDAC genes was determined by real-time PCR and HDAC proteins expression was evaluated by western blotting. Additionally, we used high-performance liquid chromatography to determine whether OVCAR-3 cells can metabolize LEV to its major metabolite, 2-pyrrolidinone-n-butyric acid (PBA), which might exert HDACI activity. LEV, however, had no apparent effect on HDAC activity, or gene and protein expression. The OVCAR-3 cell line was able to metabolize LEV to PBA, but the effect was small. Our observations suggest that VPA should be considered as a possible adjunctive drug in ovarian cancer treatment.

Inhibition of Ca(2+)-regulated exocytosis by levetiracetam, a ligand for SV2A, in antral mucous cells of guinea pigs

Levtiracetam (Lev), an inhibitor of SV2A (synaptic vesicle protein A2), affected the ATP-dependent priming of Ca(2+)-regulated exocytosis in antral mucous cells of guinea pig. In antral mucous cells, the Ca(2+)-regulated exocytosis, which is activated by acetylcholine (ACh), consists of an initial peak that declines rapidly (initial phase) followed by a second slower decline (late phase). Dinitrophenol (DNP), which depletes ATP, inhibits the ATP-dependent priming. DNP abolished the initial phase by reducing the number of primed granules, Lev decreased the frequency of initial phase, but not in the presence of DNP. Moreover, 8-bromoguanosine 3'5'-cyclic monophosphate (8BrcGMP) accelerates the ATP-dependent priming. 8BrcGMP enhances the frequency of initial phase by increasing the number of primed granule. Lev added prior to 8BrcGMP addition decreased the frequency of initial phase, but Lev added after 8BrcGMP addition did not. Thus, Lev affected the granules in the process of priming, but it did not affect the granules already primed. Lev did not affect [Ca(2+)]i in unstimulated or ACh-stimulated antral mucous cells. Immunohistochemistry and western blotting demonstrated that SV2A exists in antral mucous cells. The results suggest that SV2A plays an essential role in maintaining the process of ATP-dependent priming in antral mucous cells. In conclusion, Lev decreases the frequency of Ca(2+)-regulated exocytosis the number of primed granules by inhibiting SV2A functions, leading to a decrease in antral mucous cells.

Targeted multiplex imaging mass spectrometry in transmission geometry for subcellular spatial resolution

Targeted multiplex imaging mass spectrometry utilizes several different antigen-specific primary antibodies, each directly labeled with a unique photocleavable mass tag, to detect multiple antigens in a single tissue section. Each photocleavable mass tag bound to an antibody has a unique molecular weight and can be readily ionized by laser desorption ionization mass spectrometry. This article describes a mass spectrometry method that allows imaging of targeted single cells within tissue using transmission geometry laser desorption ionization mass spectrometry. Transmission geometry focuses the laser beam on the back side of the tissue placed on a glass slide, providing a 2 μm diameter laser spot irradiating the biological specimen. This matrix-free method enables simultaneous localization at the sub-cellular level of multiple antigens using specific tagged antibodies. We have used this technology to visualize the co-expression of synaptophysin and two major hormones peptides, insulin and somatostatin, in duplex assays in beta and delta cells contained in a human pancreatic islet.

Genome-wide prediction and analysis of human tissue-selective genes using microarray expression data

Background

Understanding how genes are expressed specifically in particular tissues is a fundamental question in developmental biology. Many tissue-specific genes are involved in the pathogenesis of complex human diseases. However, experimental identification of tissue-specific genes is time consuming and difficult. The accurate predictions of tissue-specific gene targets could provide useful information for biomarker development and drug target identification.

Results

In this study, we have developed a machine learning approach for predicting the human tissue-specific genes using microarray expression data. The lists of known tissue-specific genes for different tissues were collected from UniProt database, and the expression data retrieved from the previously compiled dataset according to the lists were used for input vector encoding. Random Forests (RFs) and Support Vector Machines (SVMs) were used to construct accurate classifiers. The RF classifiers were found to outperform SVM models for tissue-specific gene prediction. The results suggest that the candidate genes for brain or liver specific expression can provide valuable information for further experimental studies. Our approach was also applied for identifying tissue-selective gene targets for different types of tissues.

Conclusions

A machine learning approach has been developed for accurately identifying the candidate genes for tissue specific/selective expression. The approach provides an efficient way to select some interesting genes for developing new biomedical markers and improve our knowledge of tissue-specific expression.

Endocrine cells in human fetal corpus of stomach: appearance, distribution, and density

BACKGROUND

Since reports on endocrine cells and their kinetics in the corpus of the human stomach are limited, the aim of this study was to examine the appearance, localization, density, and the relationship among the endocrine cell types in the corpus of the human stomach during prenatal and early postnatal development.

METHODS

We examined chromogranin A, somatostatin, ghrelin, glucagon, and serotonin expression by immunohistochemistry in 2 embryos, 38 fetuses, and 3 infants in the corpus of human stomach.

RESULTS

Chromogranin A secreting endocrine cells were identified in the corpus at week 10 of gestation. Somatostatin cells were present from the 10th week, ghrelin and serotonin cells from the 11th week, and glucagon cells from the 12th week of gestation. Endocrine cells were present individually or clustered within the glandular base and body during the first trimester, and were present separately within the basal and central parts of glands during the second and third trimesters. Somatostatin cells were the most common type of cells (~46 %) during the first trimester, while ghrelin cells were the most numerous during the second trimester (~34 %), and in infants (~28 %). The percentage of glucagon cells was significant only during the first trimester of pregnancy (5.5 %), and the percentage of serotonin cells was only significant just before birth (4.8 %).

CONCLUSIONS

These results show, for the first time, that the largest number of endocrine cells are present in the corpus during the first trimester of prenatal development. Also, these results suggest that secretory products of endocrine cells play a role in the regulation of homeostasis, growth, and differentiation, and in human stomach function.

Preferential entry of botulinum neurotoxin A Hc domain through intestinal crypt cells and targeting to cholinergic neurons of the mouse intestine

Botulism, characterized by flaccid paralysis, commonly results from botulinum neurotoxin (BoNT) absorption across the epithelial barrier from the digestive tract and then dissemination through the blood circulation to target autonomic and motor nerve terminals. The trafficking pathway of BoNT/A passage through the intestinal barrier is not yet fully understood. We report that intralumenal administration of purified BoNT/A into mouse ileum segment impaired spontaneous muscle contractions and abolished the smooth muscle contractions evoked by electric field stimulation. Entry of BoNT/A into the mouse upper small intestine was monitored with fluorescent HcA (half C-terminal domain of heavy chain) which interacts with cell surface receptor(s). We show that HcA preferentially recognizes a subset of neuroendocrine intestinal crypt cells, which probably represent the entry site of the toxin through the intestinal barrier, then targets specific neurons in the submucosa and later (90–120 min) in the musculosa. HcA mainly binds to certain cholinergic neurons of both submucosal and myenteric plexuses, but also recognizes, although to a lower extent, other neuronal cells including glutamatergic and serotoninergic neurons in the submucosa. Intestinal cholinergic neuron targeting by HcA could account for the inhibition of intestinal peristaltism and secretion observed in botulism, but the consequences of the targeting to non-cholinergic neurons remains to be determined.

Botulism is a severe and often fatal disease in man and animals characterized by flaccid paralysis. Clostridium botulinum produces a potent neurotoxin (botulinum neurotoxin) responsible for all the symptoms of botulism. Botulism is most often acquired by ingesting preformed botulinum neurotoxin in contaminated food or after intestinal colonization by C. botulinum under certain circumstances, such as in infant botulism, and toxin production in the intestine. The first step of the disease consists in the passage of the botulinum neurotoxin through the intestinal barrier, which is still poorly understood. We investigated the trafficking of the botulinum neurotoxin in a mouse intestinal loop model, using fluorescent HcA (half C-terminal domain of the heavy chain). We observed that HcA preferentially recognizes neuroendocrine intestinal crypt cells, which likely represent the entry site of the toxin through the intestinal barrier, then targets specific neurons, mainly cholinergic neurons, in the submucosa, and later (90–120 min) in the musculosa leading to local paralytic effects such as inhibition of intestinal peristaltism. These results represent an important advance in the understanding of the initial steps of botulism intoxication and can be the basis for the development of new specific countermeasures against botulism.

Morphologic and immunohistochemical organization of the human habenular complex

The habenular complex (HbCpx) is a phylogenetically conserved brain structure located in the epithalamus of vertebrates. Despite its fundamental role in decision-making processes and the proposed link between habenular dysfunction and neuropsychiatric conditions, little is known about the structural and functional organization of the HbCpx in humans. The goal of this study was thus to provide a first systematic morphologic and immunohistochemical analysis of the human HbCpx to begin dissecting its nuclear and subnuclear organization. Our results confirmed that the human HbCpx is subdivided into medial (MHb) and lateral (LHb) nuclei, each showing a large degree of intranuclear morphologic heterogeneity. Analysis of serially stained sections using a combination of morphologic and immunohistochemical criteria allowed the distinction of five subnuclei in both the MHb and LHb. Overall, the observed subnuclear organization of the MHb in humans resembles the organization of subnuclei in the MHb of rats. The shape, relative size, and intranuclear organization of the LHb, however, show significant differences. The contribution of the LHb to the entire HbCpx is about five times larger in humans than in rats. Noteworthy, a dorsal domain of the LHb that contains afferent myelinated fibers from the stria medullaris and shows GABA-(B) -R(1) immunoreactive cells, appears substantially enlarged in humans when compared to rats. This feature seems to account for a large part of the relative growth in size of the LHb in humans and opens the intriguing possibility of an increased influence of limbic and striatal afferents into the LHb of humans.

Yapsin 1 immunoreactivity in {alpha}-cells of human pancreatic islets: implications for the processing of human proglucagon by mammalian aspartic proteases

Yapsin 1 is an aspartic protease from Saccharomyces cerevisiae and belongs to a class of aspartic proteases that demonstrate specificity for basic amino acids. It is capable of processing prohormone substrates at specific basic residue cleavage sites, similar to that of the prohormone convertases, to generate bioactive peptide hormones. An antibody raised against yapsin 1 was previously shown to immunostain endocrine cells of rat pituitary and brain as well as lysates from bovine pituitary secretory granules demonstrating the existence of yapsin 1-like aspartic proteases in mammalian endocrine tissues, potentially involved in peptide hormone production. Here, we show the specific staining of yapsin 1 immunoreactivity in the α-cells of human pancreatic islets. No staining was observed in the β- or δ-cells, indicating a specificity of the staining for glucagon-producing and not insulin- or somatostatin-producing cells. Purified yapsin 1 was also shown to process proglucagon into glucagon in vitro, demonstrating that the prototypical enzyme of this subclass of enzymes can correctly process proglucagon to glucagon. These findings suggest the existence of a yapsin 1-like enzyme exclusively in the α-cells of the islets of Langerhans in humans, which may play a role in the production of glucagon in that tissue.

Immunohistochemical and biochemical studies with region-specific antibodies to chromogranins A and B and secretogranins II and III in neuroendocrine tumors

This short review deals with our investigations in neuroendocrine tumors (NETs) with antibodies against defined epitopes of chromogranins (Cgs) A and B and secretogranins (Sgs) II and III. The immunohistochemical expression of different epitopes of the granin family of proteins varies in NE cells in normal human endocrine and non-endocrine organs and in NETs, suggesting post-translational processing. In most NETs one or more epitopes of the granins were lacking, but variations in the expression pattern occurred both in benign and malignant NETs. A few epitopes displayed patterns that may be valuable in differentiating between benign and malignant NET types, e.g., well-differentiated NET types expressed more CgA epitopes than the poorly differentiated ones and C-terminal secretoneurin visualized a cell type related to malignancy in pheochromocytomas. Plasma concentrations of different epitopes of CgA and CgB varied. In patients suffering from carcinoid tumors or endocrine pancreatic tumors the highest concentrations were found with epitopes from the mid-portion of CgA. For CgB the highest plasma concentrations were recorded for the epitope 439-451. Measurements of SgII showed that patients with endocrine pancreatic tumors had higher concentrations than patients with carcinoid tumors or pheochromocytomas. SgIII was not detectable in patients with NETs.

Hybrid model integrating immunohistochemistry and expression profiling for the classification of carcinomas of unknown primary site

Identification of the site of origin for 'malignancy with unknown primary' remains a challenge for modern pathology. Correct diagnosis is critical to defining the most beneficial treatment for the patient. Standard pathological approaches combine morphology and immunohistochemical (IHC) studies to first subclassify cytokeratin-positive carcinomas into adenocarcinoma, squamous cell carcinoma, neuroendocrine carcinoma, and urothelial carcinoma. Subsequently, organ-specific IHC-markers, if available, are used to assign the tumor's primary site of origin. Previous gene expression classifiers have shown promise in tumor classification but cannot readily be integrated into standard practice because they ignore the algorithmic hierarchy used by pathologists. Here we present a novel hybrid approach integrating a hierarchy of gene expression classifiers into the algorithmic method used with IHC. In this method, a tumor is initially assigned to one of the carcinoma subclasses by the top tier classifier. Dependent on initial classification, one of three second-tier classifiers assign primary site resulting in both carcinoma subtype and primary site classification. First tier classifier accuracies were 89%, 88%, and 75% for cross-validation, independent, and institutional independent test sets, respectively. Second tier accuracies were 87%, 90%, and 87% for adenocarcinoma, squamous, and neuroendocrine carcinoma respectively. Therefore, we can successfully separate the four main subtypes of carcinoma and subsequently assign primary site by incorporation of gene expression-based classifiers into the standard algorithmic pathology approach.

Long pulse gastric electrical stimulation induces regeneration of myenteric plexus synaptic vesicles in diabetic rats

BACKGROUND

Gastric electrical stimulation (GES) may improve delayed gastric emptying in diabetic gastroparesis, but whether enteric nervous system (ENS) is directly involved in its mechanism of improvement in gastric motility is unclear. The aims were to investigate the correlation between the changes in ENS and effects of long pulse GES on them in diabetic rats induced by streptozotocin (STZ).

METHODS

Electron microscopy, immunohistochemistry, RT-PCR and western blot were used to evaluate changes of myenteric plexus neurons and synaptic vesicles in different stages of the diabetic rats. The effects of GES were detected by same methods after pacing wires were implanted and then diabetes was induced and followed by long pulse GES.

KEY RESULTS

Since 6 weeks after STZ injection, the nerve fibres were incompact and synaptic vesicles in myenteric neurons reduced. Furthermore, the myenteric neurons showed severe damage such as partial depletion of the axon, swelling of mitochondria and seriously decreased synaptic vesicles in 12 weeks after STZ injection. The synaptophysin and PGP9.5-positive area and expressions of synaptophysin mRNA and protein decreased with the duration of diabetes. Long pulse GES could induce increase of myenteric neuronal synaptic vesicles, synaptophysin and PGP9.5-positive area and in myenteric plexus. The synaptophysin mRNA and protein expression rose after GES, whatever GES beginning early or late, short-term or long-term.

CONCLUSIONS & INFERENCES

The longer duration of diabetes, the more significant damages to myenteric neurons and synaptic vesicles of diabetic rats; long pulse GES could induce regeneration of myenteric plexus synaptic vesicles, thereby reform gastric motility.

Differential effects of levetiracetam, carbamazepine, and lamotrigine on reproductive endocrine function in adults

Animal studies have shown endocrine changes after levetiracetam treatment. The present study investigated reproductive and sexual function in patients with epilepsy (aged 18-45) treated with levetiracetam (LEV: 30 men/26 women), carbamazepine (CBZ: 63 men/30 women), or lamotrigine (LTG: 37 men/40 women) monotherapy and in healthy controls (36 men/44 women). In women, no endocrine changes were observed during LEV treatment, whereas steroid hormone-binding globulin levels were greater and progesterone levels lower in women using CBZ. Dehydroepiandrosterone sulfate levels were higher and androstenedione levels lower in LTG-treated women. Arizona Sexual Experience Scale scores, which were significantly lower in females using LTG or LEV, suggesting they have better sexual function than CBZ users and controls. In men, no drug-specific hormonal pattern was observed after LEV treatment. Male patients in all treatment groups had lower androstenedione and free testosterone. Those using CBZ had lower free androgen indices and dehydroepiandrosterone sulfate levels, and higher steroid hormone-binding globulin, follicle-stimulating hormone, and luteinizing hormone levels. Arizona Sexual Experience Scale scores for men were similar in all groups. In conclusion, LEV treatment apparently has no drug-specific sexual or endocrine side effects in men or women in this age group.

A fuller understanding of pancreatic neuroendocrine tumours combined with aggressive management improves outcome

BACKGROUND

Neuroendocrine tumours of the pancreas (PNETs) represent 1-2% of all pancreatic tumours. The terms 'islet cell tumours' and 'carcinoids' of the pancreas should be avoided. The aim of this review is to offer an overview of the history and diagnosis of PNETs followed by a discussion of the available treatment options.

METHODS

A search on PubMed using the keywords 'neuroendocrine', 'pancreas' and 'carcinoid' was performed to identify relevant literature over the last 30 years.

RESULTS

The introduction of a revised classification of neuroendocrine tumours by the World Health Organisation (WHO) in 2000 significantly changed our understanding of and approach to the management of these tumours. Advances in laboratory and radiological techniques have also led to an increased detection of PNETs. Surgery remains the only treatment that offers a chance of cure with increasing number of non-surgical options serving as beneficial adjuncts. The better understanding of the behaviours of PNETs together with improvements in tumour localisation has resulted in a more aggressive management strategy with a concomitant improvement in symptom palliation and a prolongation of survival.

CONCLUSION

Due to their complex nature and the wide range of therapeutic options, the involvement of specialists from all necessary disciplines in a multidisciplinary team setting is vital to provide optimal treatment of this disease.

Differential effects of antiepileptic drugs on steroidogenesis in a human in vitro cell model

OBJECTIVES

To better understand the interaction of antiepileptic drugs and production of sex hormones, possible effects of valproate (VPA), levetiracetam (LEV) and carbamazepine (CBZ) on steroidogenesis were investigated in the human adrenal carcinoma cell line H295R.

MATERIALS AND METHODS

H295R cells were exposed to different concentrations of VPA, LEV or CBZ for 48 h. Sex hormone concentrations and mRNA expression levels were analyzed via radioimmunoassay and quantitative real time (RT)-PCR, respectively.

RESULTS

In VPA-exposed cells estradiol levels decreased in a dose-dependent manner, while testosterone and progesterone levels were unaffected. Expression of 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGR), steroidogenic acute regulatory protein (StAR), CYP11a, CYP17, CYP21, 3betaHSD2, 17betaHSD1 was downregulated and expression of CYP11beta2 was upregulated. No effect on sex hormone production was observed under influence of LEV or CBZ. Expression of StAR, CYP17, CYP19 and 3betaHSD2 was downregulated in LEV-exposed cells, and expression of HMGR, CYP11beta2 and CYP17 was downregulated in CBZ-exposed cells.

CONCLUSIONS

VPA exposure resulted in a decrease in estradiol levels and a general downregulation of expression of genes encoding for enzymes early in steroidogenesis. No consistent changes were seen with LEV or CBZ exposure.

Botulinum toxin type A inhibits the growth of LNCaP human prostate cancer cells in vitro and in vivo

INTRODUCTION AND OBJECTIVE

Botulinum toxin type A (BTA) intraprostatic injection induces an improvement of urinary symptoms related to benign prostatic hypertrophy (BPH). Infra-clinical prostate cancer (PCa) foci and pre-neoplasic lesions occur concomitantly with BPH in a significant number of patients. The objective of this study was to address whether BTA influences the growth of prostate tumors.

METHODS

Proliferation of PC-3 and LNCaP cell lines exposed or not to BTA (Botox) was assessed and compared. Presence of synaptic vesicle 2 (SV2) protein, the membrane receptor of BTA, was studied in both cell lines. After nude mice bearing LNCaP xenografts received intra-tumoral BTA or saline injection, tumor volume, serum PSA, histopathology and detection of apoptosis were comparatively assessed.

RESULTS

BTA significantly reduced LNCaP cell proliferation and increased apoptosis in a dose-dependent manner but did not affect PC-3. The SV2 receptor was present in both cell lines at a ratio of 4:1 (LNCaP/PC-3). One unit of BTA resulted in a significantly lower growth rate and slower PSA progression over 28 days compare to controls. The tumors were morphologically similar. There were significantly more apoptotic cells compared to controls.

CONCLUSION

BTA inhibits the growth of LNCaP human PCa cells in vitro and in vivo. These findings indicate that intra-prostatic BTA injections to treat BPH are unlikely to promote the growth of co-existing infra-clinical PCa foci in men. A potential inhibitory effect of BTA on the growth of human PCa should be further studied.

The solute carrier (SLC) complement of the human genome: phylogenetic classification reveals four major families

Solute carriers (SLCs) is the largest group of transporters, embracing transporters for inorganic ions, amino acids, neurotransmitters, sugars, purines and fatty acids among other substrates. We mined the finished assembly of the human genome using Hidden Markov Models (HMMs) obtaining a total of 384 unique SLC sequences. Detailed clustering and phylogenetic analysis of the entire SLC family showed that 15 of the families place into four large phylogenetic clusters with the largest containing eight SLC families, suggesting that many of the distinct families of SLCs have a common evolutionary origin. This study represents the first overall genomic roadmap of the SLCs providing large sequence sets and clarifies the phylogenetic relationships among the families of the second largest group of membrane proteins.

The immunohistochemical localization of synaptophysin protein (p38) in the gastro-entero-pancreatic (GEP) system of reptiles

The gastro-entero-pancreatic (GEP) system of four reptilian species: turtle (Emys orbicularis), lizards (Lacerta viridis and Lacerta agilis) and snake (Natrix natrix) has been investigated immunohistochemically for the presence and topographic distribution of synaptophysin. Among the studied reptiles, only in turtles were neural, glial and neuroendocrine elements labelled for this marker protein. Semi-quantitative evaluation of the immunolabelled neural structures distributed throughout the gastroenteric wall revealed, with two exceptions, highly significant mean differences between the successive gut segments. Significant mean differences were noted also between myenteric and submucosal neurons immunolabelled in the various gastroenteric regions. Moreover, the comparison of ganglionic perikarya groups showed, at least in the stomach, significant mean differences. The amounts of immunopositive glial cells seemed to vary similarly to those of nerve fibers along the entire gastrointestinal tract. Finally, every "closed" and "open" population of immunopositive epithelial cells showed typical fluctuations along the gut. In addition to the distribution of synaptophysin in the GEP system of turtles, the above findings furnish evidence that this marker protein, which is widespread in mammals, is only occasionally expressed in reptiles and probably in most poikilothermic vertebrates.

Receptor-mediated transcytosis of botulinum neurotoxin A through intestinal cell monolayers

Botulism is mainly acquired by the oral route, and botulinum neurotoxin (BoNT) escapes the gastrointestinal tract by crossing the digestive epithelial barrier prior to gaining access to the nerve endings. Here, we show that biologically active BoNT/A crosses intestinal cell monolayers via a receptor-mediated transcytosis, including a transport inhibition at 4 degrees C and a passage at 37 degrees C in a saturable manner within 30-60 min. BoNT/A passage rate was about 10-fold more efficient through the intestinal crypt cell line m-IC(cl2), than through the carcinoma Caco-2 or T84 cells, and was not increased when BoNT/A was associated with the non-toxic proteins (botulinum complex). Like for neuronal cells, BoNT/A binding to intestinal cells was mediated by the half C-terminal domain as tested by fluorescence-activated cytometry and by transcytosis competition assay. A 'double receptor model' has been proposed in which BoNT/A interacts with gangliosides of GD(1b) and GT(1b) series as well as SV2 protein. Gangliosides of GD(1b) and GT(1b) series and recombinant intravesicular SV2-C domain partially impaired BoNT/A transcytosis, suggesting a putative role of gangliosides and SV2 or a related protein in BoNT/A transcytosis through Caco-2 and m-IC(cl2) cells.