On predatory fungi feeding on free-living amoebae harbouring yeast-like endoparasites

Amoebae of the genus Vannella isolated from an ornamental fish aquarium were found to be infected with fungi. Upon plate culture, amoeba-trapping hyphal filaments were developed, and the amoeba trophozoites were found to harbour yeast-like parasites in their cytoplasm. Transfection of hyphae to a laboratory strain of Vannella resulted in the formation of conidia indicating the possible presence of zygomycetes of the genus Acaulopage, while efforts to culture the endoparasite remained unsuccessful. Biomolecular analysis based on rDNA revealed the presence of two distinct types of fungi, confirming the filamentous form as Acaulopage sp. (Zoopagomycota, Zoopagales) and identifying the yeast-like endoparasite as Cladosporium sp. (Ascomycota, Cladosporiales). To our knowledge, this is the first report of amoebae infected with Cladosporium.

Deciphering the Emulsification Process to Create an Albumin-Perfluorocarbon-(o/w) Nanoemulsion with High Shelf Life and Bioresistivity

This work aimed at the development of a stable albumin-perfluorocarbon (o/w) emulsion as an artificial oxygen carrier suitable for clinical application. So far, albumin-perfluorocarbon-(o/w) emulsions have been successfully applied in preclinical trials. Cross-linking a variety of different physical and chemical methods for the characterization of an albumin-perfluorocarbon (PFC)-(o/w) emulsion was necessary to gain a deep understanding of its specific emulsification processes during high-pressure homogenization. High-pressure homogenization is simple but incorporates complex physical reactions, with many factors influencing the formation of PFC droplets and their coating. This work describes and interprets the impact of albumin concentration, homogenization pressure, and repeated microfluidizer passages on PFC-droplet formation; its influence on storage stability; and the overcoming of obstacles in preparing stable nanoemulsions. The applied methods comprise dynamic light scattering, static light scattering, cryo- and non-cryo-scanning and transmission electron microscopies, nuclear magnetic resonance spectroscopy, light microscopy, amperometric oxygen measurements, and biochemical methods. The use of this wide range of methods provided a sufficiently comprehensive picture of this polydisperse emulsion. Optimization of PFC-droplet formation by means of temperature and pressure gradients results in an emulsion with improved storage stability (tested up to 5 months) that possibly qualifies for clinical applications. Adaptations in the manufacturing process strikingly changed the physical properties of the emulsion but did not affect its oxygen capacity.

Thyroid Hormone Deficiency Modifies Hepatic Lipid Droplet Morphology and Molecular Properties in Lithogenic-Diet Supplemented Mice

OBJECTIVE

Thyroid hormones have been associated with a hepatic lipid lowering effect and thyroid function has been shown to play a substantial role in development of non-alcoholic fatty liver disease. Hepatic lipid droplets differ in the number, size and molecular properties depending on metabolic state or pathological condition. However, in how far thyroid hormone deficiency affects hepatic lipid droplet morphology and molecular properties is still poorly understood. Therefore, we performed a study in mice using a lithogenic diet model of steatohepatitis and modulated the thyroid hormone status.

METHODS

Male and female three months old C57BL/6 mice were divided into a euthyroid (control), a lithogenic (litho) and a lithogenic+thyroid hormone deficient (litho+hypo) group and treated for six weeks. Hepatic transmission electron microscopy and gene expression analysis of lipid-droplet associated proteins were performed.

RESULTS

Increased mean diameters of hepatic lipid droplets and a shift towards raised electron-density in lipid droplets was observed under thyroid hormone deficiency. Furthermore thyroid hormone deficiency altered hepatic expression of genes involved in lipophagy and triacylglycerol mobilization. Interestingly, while the impact of thyroid hormone deficiency on lipid droplet morphology seems to be sex-independent, hepatic lipid droplet-associated gene expression differed significantly between both sexes.

CONCLUSION

This study demonstrates that thyroid hormone deficiency alters hepatic lipid droplet morphology and hepatic gene expression of lipid droplet-associated proteins in a lithogenic diet mouse model of steatohepatitis.

Characterization of two types of intranuclear hepatocellular inclusions in NAFLD

Nuclear inclusions (NI) are a common finding in hepatocytes from patients with liver disease especially in diabetes mellitus and non-alcoholic fatty liver disease (NAFLD) but studies examining the shape and content of these inclusions in detail are lacking. In this study we define two distinct types of NI in NAFLD: inclusions bounded by the nuclear membrane, containing degenerative cell organelles and heterolysosomes (type1) and inclusions with deposits of glycogen but without any kind of organelles and delimiting membrane (type2). NI in 77 paraffin-embedded patients of NAFLD including NAFL and non-alcoholic steatohepatitis (NASH) were analyzed. In 4–12% of type1 NI immunopositivity for the autophagy-associated proteins LC3B, ubiquitin, p62/sequestosome1, cathepsin D and cathepsin B were detected with co-localizations of ubiquitin and p62; type2 NI showed no immunoreactivity. Three-dimensional reconstructions of isolated nuclei revealed that NI type1 are completely enclosed within the nucleus, suggesting that NI, although probably derived from cytoplasmic invaginations, are not just simple invaginations. Our study demonstrates two morphologically different types of inclusions in NAFLD, whereby both gained significantly in number in advanced stages. We suggest that the presence of autophagy-associated proteins and degenerated organelles within type1 NI plays a role in disease progression.

Acid ceramidase of macrophages traps herpes simplex virus in multivesicular bodies and protects from severe disease

Macrophages have important protective functions during infection with herpes simplex virus type 1 (HSV-1). However, molecular mechanisms that restrict viral propagation and protect from severe disease are unclear. Here we show that macrophages take up HSV-1 via endocytosis and transport the virions into multivesicular bodies (MVBs). In MVBs, acid ceramidase (aCDase) converts ceramide into sphingosine and increases the formation of sphingosine-rich intraluminal vesicles (ILVs). Once HSV-1 particles reach MVBs, sphingosine-rich ILVs bind to HSV-1 particles, which restricts fusion with the limiting endosomal membrane and prevents cellular infection. Lack of aCDase in macrophage cultures or in Asah1^-/- mice results in replication of HSV-1 and Asah1^-/- mice die soon after systemic or intravaginal inoculation. The treatment of macrophages with sphingosine enhancing compounds blocks HSV-1 propagation, suggesting a therapeutic potential of this pathway. In conclusion, aCDase loads ILVs with sphingosine, which prevents HSV-1 capsids from penetrating into the cytosol.

Evaluation of dsDNA from extracellular vesicles (EVs) in pediatric AML diagnostics

Acute myeloid leukemia (AML) is a heterogeneous malignant disease characterized by a collection of genetic and epigenetic changes. As a consequence, AML can evolve towards more aggressive subtypes during treatment, which require additional therapies to prevent future relapse. As we have previously detected double-stranded DNA (dsDNA) in tumor-derived extracellular vesicles (EVs), in this current study we attempted to evaluate the potential diagnostic applications of AML EV-dsDNA derived from primary bone marrow and peripheral blood plasma samples. EVs from plasma of 29 pediatric AML patients (at initial diagnosis or during treatment) were isolated by ultracentrifugation, after which dsDNA was extracted from obtained EVs and analyzed for leukemia-specific mutations using next generation sequencing (NGS) and GeneScan-based fragment-length analysis. In 18 out of 20 patients, dsDNA harvested from EVs mirrored the (leukemia-specific) mutations found in the genomic DNA obtained from primary leukemia cells. In the nanoparticle tracking analysis (NTA), a decrease in EV numbers was observed in patients after treatment compared with initial diagnosis. Following treatment, in 75 samples out of the 79, these mutations were no longer detectable in EV-dsDNA. In light of our results, we propose the use of leukemia-derived EV-dsDNA as an additional measure for mutational status and, potentially, treatment response in pediatric AML.

New insights into intranuclear inclusions in thyroid carcinoma: Association with autophagy and with BRAFV600E mutation

Background

Intranuclear inclusions (NI) in normal and neoplastic tissues have been known for years, representing one of the diagnostic criteria for papillary thyroid carcinoma (PTC). BRAF activation is involved among others in autophagy. NI in hepatocellular carcinoma contain autophagy-associated proteins. Our aim was to clarify if NI in thyroid carcinoma (TC) have a biological function.

Methods

NI in 107 paraffin-embedded specimens of TC including all major subtypes were analyzed. We considered an inclusion as positive if it was delimited by a lamin AC (nuclear membrane marker) stained intact membrane and completely closed. Transmission electron microscopy (TEM), immunohistochemistry (IHC), immunofluorescence (IF) and 3D reconstruction were performed to investigate content and shape of NI; BRAF^V600E mutation was analyzed by next generation sequencing.

Results

In 29% of the TCs at least one lamin AC positive intranuclear inclusion was detected; most frequently (76%) in PTCs. TEM analyses revealed degenerated organelles and heterolysosomes within such NI; 3D reconstruction of IF stained nuclei confirmed complete closure by the nuclear membrane without any contact to the cytoplasm. NI were positively stained for the autophagy-associated proteins LC3B, ubiquitin, cathepsin D, p62/sequestosome1 and cathepsin B in 14–29% of the cases. Double-IF revealed co-localization of LC3B & ubiquitin, p62 & ubiquitin and LC3B & p62 in the same NI. BRAF^V600E mutation, exclusively detected in PTCs, was significantly associated with the number of NI/PTC (p = 0.042) and with immunoreactivity for autophagy-associated proteins in the NI (p≤0.035). BRAF-IHC revealed that some of these BRAF-positive thyrocytes contained mutant BRAF in their NI co-localized with autophagy-associated proteins.

Conclusions

NI are completely delimited by nuclear membrane in TC. The presence of autophagy-associated proteins within the NI together with degenerated organelles and lysosomal proteases suggests their involvement in autophagy and proteolysis. Whether and how BRAF^V600E protein is degraded in NI needs further investigation.

Intranuclear inclusions in hepatocellular carcinoma contain autophagy-associated proteins and correlate with prolonged survival

For decades, intranuclear inclusions in many normal and neoplastic cells have been considered to be mere invaginations of cytoplasm into the nucleus without any notable function or influence on disease. We investigated such inclusions in 75 specimens of hepatocellular carcinoma (HCC). In this context we demonstrate that these inclusions are true inclusions, completely closed and delimited by the nuclear membrane, containing degenerate cell organelles and lysosomal proteins. Moreover, their occurrence was positively associated with patient survival but not with tumour grade or stage. In a standardised area a mean of 124 inclusions per specimen was present in the tumorous liver tissue in contrast to 5 inclusions in the non‐tumorous adjacent section and 89% of all scrutinised HCC showed at least one membrane‐bound nuclear inclusion. Ultrastructural characterisation by transmission electron microscopy revealed degenerative materials such as residues of lysosomes, endoplasmic reticulum and Golgi apparatus within the inclusions. Due to the fact that the content of the inclusions appears to be more condensed than cytoplasm and contains fewer intact cell organelles, we assume that they are not mere invaginations of cytoplasm. Three dimensional (3D) reconstruction of isolated and immunofluorescence stained nuclei showed that the inclusions are completely located within the nucleus without any connection to the cytoplasm. The limiting membrane of the inclusions contained lamin B suggesting nuclear membrane origin. The content of the inclusions stained for the autophagy‐associated proteins p62, ubiquitin, LC3B, cathepsin B and cathepsin D. Triple immunofluorescence staining followed by 3D reconstruction revealed co‐localisation of p62, ubiquitin and LC3B in the same inclusion. Our observations uncover that these inclusions are real inclusions completely surrounded by the nucleus. We propose that the presence of autophagy‐associated proteins and proteases within the inclusions contribute to beneficial survival.

Autophagic degradation of lamins facilitates the nuclear egress of herpes simplex virus type 1

Turan and Grosche et al. show that herpes simplex virus type 1 (HSV-1) infection leads to autophagic degradation of nuclear lamins in immature dendritic cells, facilitating HSV-1 nuclear egress and the formation of infectious progeny virus. In mature dendritic cells, autophagy is inhibited due to elevated KIF1B and KIF2A protein levels.

Dendritic cells (DCs) are crucial for the induction of potent antiviral immune responses. In contrast to immature DCs (iDCs), mature DCs (mDCs) are not permissive for infection with herpes simplex virus type 1 (HSV-1). Here, we demonstrate that HSV-1 infection of iDCs and mDCs induces autophagy, which promotes the degradation of lamin A/C, B1, and B2 in iDCs only. This in turn facilitates the nuclear egress of progeny viral capsids and thus the formation of new infectious particles. In contrast, lamin protein levels remain stable in HSV-1–infected mDCs due to an inefficient autophagic flux. Elevated protein levels of KIF1B and KIF2A in mDCs inhibited lamin degradation, likely by hampering autophagosome–lysosome fusion. Therefore, in mDCs, fewer progeny capsids were released from the nuclei into the cytosol, and fewer infectious virions were assembled. We hypothesize that inhibition of autophagic lamin degradation in mDCs represents a very powerful cellular counterstrike to inhibit the production of progeny virus and thus viral spread.

Precipitation with polyethylene glycol followed by washing and pelleting by ultracentrifugation enriches extracellular vesicles from tissue culture supernatants in small and large scales

Extracellular vesicles (EVs) provide a complex means of intercellular signalling between cells at local and distant sites, both within and between different organs. According to their cell-type specific signatures, EVs can function as a novel class of biomarkers for a variety of diseases, and can be used as drug-delivery vehicles. Furthermore, EVs from certain cell types exert beneficial effects in regenerative medicine and for immune modulation. Several techniques are available to harvest EVs from various body fluids or cell culture supernatants. Classically, differential centrifugation, density gradient centrifugation, size-exclusion chromatography and immunocapturing-based methods are used to harvest EVs from EV-containing liquids. Owing to limitations in the scalability of any of these methods, we designed and optimised a polyethylene glycol (PEG)-based precipitation method to enrich EVs from cell culture supernatants. We demonstrate the reproducibility and scalability of this method and compared its efficacy with more classical EV-harvesting methods. We show that washing of the PEG pellet and the re-precipitation by ultracentrifugation remove a huge proportion of PEG co-precipitated molecules such as bovine serum albumine (BSA). However, supported by the results of the size exclusion chromatography, which revealed a higher purity in terms of particles per milligram protein of the obtained EV samples, PEG-prepared EV samples most likely still contain a certain percentage of other non-EV associated molecules. Since PEG-enriched EVs revealed the same therapeutic activity in an ischemic stroke model than corresponding cells, it is unlikely that such co-purified molecules negatively affect the functional properties of obtained EV samples. In summary, maybe not being the purification method of choice if molecular profiling of pure EV samples is intended, the optimised PEG protocol is a scalable and reproducible method, which can easily be adopted by laboratories equipped with an ultracentrifuge to enrich for functional active EVs.

A systematic electron microscopic study on the uptake of barium sulphate nano-, submicro-, microparticles by bone marrow-derived phagocytosing cells

Nanoparticles can act as transporters for synthetic molecules and biomolecules into cells, also in immunology. Antigen-presenting cells like dendritic cells are important targets for immunotherapy in nanomedicine. Therefore, we have used primary murine bone marrow-derived phagocytosing cells (bmPCs), i.e. dendritic cells and macrophages, to study their interaction with spherical barium sulphate particles of different size (40 nm, 420 nm, and 1 µm) and to follow their uptake pathway. Barium sulphate is chemically and biologically inert (no dissolution, no catalytic effects), i.e. we can separate the particle uptake effect from potential biological reactions. The colloidal stabilization of the nanoparticles was achieved by a layer of carboxymethylcellulose (CMC) which is biologically inert and gives the particles a negative zeta potential (i.e. charge). The particles were made fluorescent by conjugating 6-aminofluoresceine to CMC. Their uptake was visualized by flow cytometry, confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and correlative light and electron microscopy (CLEM). Barium sulphate particles of all sizes were readily taken up by dendritic cells and even more by macrophages, with the uptake increasing with time and particle concentration. They were mainly localized inside phagosomes, heterophagosomes, and in the case of nanoparticles also in the nearby cytosol. No particles were found in the nucleus. In nanomedicine, inorganic nanoparticles from the nanometer to the micrometer size are therefore well suited as transporters of biomolecules, including antigens, into dendritic cells and macrophages. The presented model system may also serve to describe the aseptic loosening of endoprostheses caused by abrasive wear of inert particles and the subsequent cell reaction, a question which relates to the field of nanotoxicology. STATEMENT OF SIGNIFICANCE: The interaction of particles and cells is at the heart of nanomedicine and nanotoxicology, including abrasive wear from endoprostheses. It also comprises the immunological reaction to different kinds of nanomaterials, triggered by an immune response, e.g. by antigen-presenting cells. However, it is often difficult to separate the particle effect from a chemical or biochemical reaction to particles or their cargo. We show how chemically inert barium sulphate particles with three different sizes (nano, sub-micro, and micro) interact with relevant immune cells (primary dendritic cells and macrophages). Particles of all three sizes are readily taken up into both cell types by phagocytosis, but the uptake by macrophages is significantly more prominent than that by dendritic cells. The cells take up particles until they are virtually stuffed, but without direct adverse effect. The uptake increases with time and particle concentration. Thus, we have an ideal model system to follow particles into and inside cells without the side effect of a chemical particle effect, e.g. by degradation or ion release.

[Lysosomal acid lipase deficiency (LAL-D) : Diagnostic and therapeutic options in an underdiagnosed disease]

BACKGROUND AND CLINICAL SETTING

Lysosomal acid lipase deficiency is an autosomal recessive storage disease caused by mutations in the LIPA gene. The accumulation of cholesteryl esters and triglycerides in hepatocytes lead to hepatomegaly with progressive fibrosis and liver cirrhosis. Characteristically, patients have a hepatomegaly combined with high serum levels of cholesterol, LDL-cholesterol and in some cases triglyceride, whereas HDL-cholesterol is decreased. Histologically, hepatocytes show a microvesicular steatosis with typically ballooned Kupffer cells. Even though histological morphology is typical, it is not characteristic. Therefore LAL-D is supposed to be an underdiagnosed disease with a high number of unreported cases misdiagnosed as uncharacteristic fatty liver disease (NASH, NAFLD, cryptogenic liver cirrhosis). Further, there is overlap with other storage diseases, complicating a correct diagnosis.

THERAPY

Until recently, different therapeutic options could not prevent development of liver cirrhosis. Patients with Wolman's disease have an especially rapid progression and die within the first six months of life. With the recent development of a new enzyme replacement therapy with sebelipase alfa (Kanuma ®), new therapeutic options with significant improvement of dyslipidemia and reduction of transaminases have become reality. Positive clinical results seem to have the potential to significantly raise life expectancy.

CONCLUSION

These new therapeutic options warrant an increase in awareness of LAL-D by clinicians and pathologists. Correct diagnosis of LAL-D is important for effective therapy and long-term survival.

A Distinct Oncogenerative Multinucleated Cancer Cell Serves as a Source of Stemness and Tumor Heterogeneity

The effects of anticancer treatments on cell heterogeneity and their proliferative potential play an important role in tumor persistence and metastasis. However, little is known about de-polyploidization, cell fate, and physiologic stemness of the resulting cell populations. Here, we describe a distinctive cell type termed "pregnant" P1 cells found within chemotherapy-refractory ovarian tumors, which generate and gestate daughter generation Gn cells intracytoplasmically. Release of Gn cells occurred by ejection through crevices in the P1 cell membrane by body contractions or using a funiculus-like structure. These events characterized a not yet described mechanism of cell segregation. Maternal P1 cells were principally capable of surviving parturition events and continued to breed and nurture Gn progenies. In addition, P1 cells were competent to horizontally transmit offspring Gn cells into other specific proximal cells, injecting them to receptor R1 cells via cell-cell tunneling. This process represents a new mechanism used by tumor cells to invade surrounding tissues and ensure life cycles. In contrast to the pregnant P1 cells with low expression of stem cell markers despite their physiologic stemness, the first offspring generations of daughter G1 cells expressed high levels of ovarian cancer stem cell markers. Furthermore, both P1 and Gn cells overexpressed multiple human endogenous retroviral envelope proteins. Moreover, programmed death-ligand 1 and the immunosuppressive domain of the retroviral envelope proteins were also overexpressed in P1 cells, suggesting effective protection against the host immune system. Together, our data suggest that P1 oncogenerative cancer cells exhibit a not yet described cell biological mechanism of persistence and transmission of malignant cells in patients with advanced cancers.Significance: P1 oncogenerative cell entities express low levels of CSC markers, which are characteristic of their histological origin. Cancer Res; 78(9); 2318-31. ©2018 AACR.

Protection of Oligodendrocytes Through Neuronal Overexpression of the Small GTPase Ras in Hyperoxia-Induced Neonatal Brain Injury

Prematurely born infants are highly susceptible to various environmental factors, such as inflammation, drug exposure, and also high environmental oxygen concentrations. Hyperoxia induces perinatal brain injury affecting white and gray matter development. It is well known that mitogen-activated protein kinase signaling is involved in cell survival, proliferation, and differentiation. Therefore, we aim to elucidate cell-specific responses of neuronal overexpression of the small GTPase Ras on hyperoxia-mediated brain injury. Six-day-old (P6) synRas mice (neuronal Ras overexpression under the synapsin promoter) or wild-type littermates were kept under hyperoxia (80% oxygen) or room air (21% oxygen) for 24 h. Apoptosis was analyzed by Western blot of cleaved Caspase-3 and neuronal and oligodendrocyte degeneration via immunohistochemistry. Short-term differentiation capacity of oligodendrocytes was assessed by quantification of myelin basic protein expression at P11. Long-lasting changes of hyperoxia-induced alteration of myelin structures were evaluated via transmission electron microscopy in young adult animals (P42). Western blot analysis of active Caspase-3 demonstrates a significant upregulation in wild-type littermates exposed to hyperoxia whereas synRas mice did not show any marked alteration of cleaved Caspase-3 protein levels. Immunohistochemistry revealed a protective effect of neuronal Ras overexpression on neuron and oligodendrocyte survival. Hyperoxia-induced hypomyelination in wild-type littermates was restored in synRas mice. These short-term protective effects through promotion of neuronal survival translated into long-lasting improvement of ultrastructural alterations of myelin sheaths in mice with neuronal overexpression of Ras compared with hyperoxic wild-type mice. Our data suggest that transgenic increase of neuronal Ras activity in the immature brain results in secondary protection of oligodendrocytes from hyperoxia-induced white matter brain injury.

Cisplatin alters the function and expression of N-type voltage-gated calcium channels in the absence of morphological damage of sensory neurons

Platinum-based chemotherapeutic agents, such as cisplatin, are still frequently used for treating various types of cancer. Besides its high effectiveness, cisplatin has several serious side effects. One of the most common side effects is dorsal root ganglion (DRG) neurotoxicity. However, the mechanisms underlying this neurotoxicity are still unclear and controversially discussed. Cisplatin-mediated modulation of voltage-gated calcium channels (VGCCs) in the DRG neurons has been shown to alter intracellular calcium homeostasis, a process critical for the induction of neurotoxicity. Using the whole-cell patch-clamp technique, immunostaining, behavioural experiments and electron microscopy (EM) of rat DRGs, we here demonstrate that cisplatin-induced neurotoxicity is due to functional alteration of VGCC, but not due to morphological damage. In vitro application of cisplatin (0.5 µM) increased N-type VGCC currents (I_Ca(V)) in small DRG neurons. Repetitive in vivo administration of cisplatin (1.5 mg/kg, cumulative 12 mg/kg) increased the protein level of N-type VGCC over 26 days, with the protein level being increased for at least 14 days after the final cisplatin administration. Behavioural studies revealed that N-type VGCCs are crucial for inducing symptoms of cisplatin-related neuropathic pain, such as thermal and mechanical hyperalgesia. EM and histology showed no evidence of any structural damage, apoptosis or necrosis in DRG cells after cisplatin exposure for 26 days. Furthermore, no nuclear DNA damage in sensory neurons was observed. Here, we provide evidence for a mainly functionally driven induction of neuropathic pain by cisplatin.

Cytotoxic stress induces transfer of mitochondria-associated human endogenous retroviral RNA and proteins between cancer cells

About 8 % of the human genome consists of human endogenous retroviruses (HERVs), which are relicts of ancient exogenous retroviral infections incurred during evolution. Although the majority of HERVs have functional gene defects or epigenetic modifications, many of them are still able to produce retroviral proteins that have been proposed to be involved in cellular transformation and cancer development.

We found that, in chemo-resistant U87^RETO glioblastoma cells, cytotoxic stress induced by etoposide promotes accumulation and large-scale fission of mitochondria, associated with the detection of HERV-WE₁ (syncytin-1) and HERV-FRD₁ (syncytin-2) in these organelles. In addition, mitochondrial preparations also contained the corresponding receptors, i.e. ASCT2 and MFSD2. We clearly demonstrated that mitochondria associated with HERV-proteins were shuttled between adjacent cancer cells not only via tunneling tubes, but also by direct cellular uptake across the cell membrane. Furthermore, anti-syncytin-1 and anti-syncytin-2 antibodies were able to specifically block this direct cellular uptake of mitochondria even more than antibodies targeting the cognate receptors.

Here, we suggest that the association of mitochondria with syncytin-1/syncytin-2 together with their respective receptors could represent a novel mechanism of cell-to-cell transfer. In chemotherapy-refractory cancer cells, this might open up attractive avenues to novel mitochondria-targeting therapies.

Therapy with Multipotent Mesenchymal Stromal Cells Protects Lungs from Radiation-Induced Injury and Reduces the Risk of Lung Metastasis

AIMS

Previous thorax irradiation promotes metastatic spread of tumor cells to the lung. We hypothesized that vascular damage facilitates lung metastasis after thorax irradiation and that therapeutically applied multipotent mesenchymal stromal cells (MSCs) with reported repair activity may prevent these adverse effects of ionizing radiation by protecting lung endothelia from radiation-induced damage.

RESULTS

Previous whole-thorax irradiation (WTI) with 15 Gy significantly enhanced seeding and metastatic growth of tumor cells in the lung. WTI was further associated with endothelial cell damage, senescence of lung epithelial cells, and upregulation of invasion- and inflammation-promoting soluble factors, for example, endothelial matrix metalloproteinase 2 (Mmp2), its activator Mmp14, the cofactor tissue inhibitor of metalloproteinases 2 (Timp2), chemokine (C-C motif) ligand 2 (Ccl2), and urokinase-type plasminogen activator (Plau/uPA), and recruitment of CD11b+CD11c- myelomonocytic cells. Inhibition of Mmp2 counteracted radiation-induced vascular dysfunction without preventing increased metastasis. In contrast, therapy with bone marrow or aorta-derived MSCs within 2 weeks postirradiation antagonized radiation-induced damage to resident cells as well as the resulting secretome changes and abrogated the metastasis-promoting effects of WTI.

INNOVATION

Therapy with MSCs protects lungs from radiation-induced injury and reduces the risk of lung metastasis. MSC-mediated inhibition of Mmp2 mediates their protective effects at the vasculature. Furthermore, local and systemic effects such as inhibition of radiation-induced senescence of bronchial epithelial cells and associated secretion of immunomodulatory factors may participate in the inhibitory effect of MSCs on lung metastasis.

CONCLUSION

MSC therapy is a promising strategy to prevent radiation-induced lung injury and the resulting increased risk of metastasis.

Therapeutic potential of antiviral drugs targeting chemorefractory colorectal adenocarcinoma cells overexpressing endogenous retroviral elements

Background

Endoretroviruses account for circa 8 % of all transposable elements found in the genome of humans and other animals. They represent a genetic footprint of ancestral germ-cell infections of exoviruses that is transmittable to the progeny by Mendelian segregation. Traces of human endogenous retroviruses are physiologically expressed in ovarial, testicular and placental tissues as well as in stem cells. In addition, a number of these fossil viral elements have also been related to carcinogenesis. However, a relation between endoretroviruses expression and chemoresistance has not been reported yet.

Methods

Twenty colorectal carcinoma patient samples were scrutinized for HERV-W_E1 and HERV-FRD₁ endoretroviruses using immunohistochemical approaches. In order to search for differential expression of these elements in chemotherapy refractory cells, a resistant HCT8 colon carcinoma subline was developed by serial etoposide exposure. Endoretroviral elements were detected by immunocytochemical staining, qPCR and ELISA. IC₅₀-values of antiviral and cytostatic drugs in HCT8 cells were determined by MTT proliferation assay. The antivirals-cytostatics interaction was evaluated by the isobologram method.

Results

In this work, we show for the first time that HERV-W_E1, HERV-FRD₁, HERV-3₁, and HERV-V₁ are a) simultaneously expressed in treatment-naïve colon carcinoma cells and b) upregulated after cytostatic exposure, suggesting that these retroviral elements are intimately related to chemotherapy resistance. We found a number of antiviral drugs to have cytotoxic activity and the ability to force the downregulation of HERV proteins in vitro. We also demonstrate that the use of different antiviral compounds alone or in combination with anticancer agents results in a synergistic antiproliferative effect and downregulation of different endoretroviral elements in highly chemotherapy-resistant colorectal tumor cells.

Conclusions

Enhanced HERV-expression is associated with chemoresistance in colon carcinomas which can be overcome by antiviral drugs alone or in combination with anticancer drugs. Therefore, the introduction of antiviral compounds to the current chemotherapy regimens potentially improves patient outcomes.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-015-0199-5) contains supplementary material, which is available to authorized users.

Cell death induction by the BH3 mimetic GX15-070 in thyroid carcinoma cells

Background

The evasion of cell death is one of the hallmarks of cancer, contributing to both tumor progression and resistance to therapy. Dedifferentiated and anaplastic thyroid carcinomas that do not take up radioiodine are resistant to conventional anticancer treatments and patients with these tumors are difficult to treat. BH3 mimetics are a new class of drugs that target anti-apoptotic proteins of the BCL-2 family and promote cell death. The purpose of this study was to analyze the molecular effects of the BH3 mimetic GX15-070 on thyroid carcinoma cell lines and to characterize cell death induced by GX15-070.

Methods

A total of 17 cell lines derived from follicular, papillary, and anaplastic thyroid carcinomas were treated with GX15-070. Cell viability was measured with MTT assay while cell cycle phase distribution and subG1 peaks were determined after propidium iodide staining. We assessed cell death via the caspase 3/7 activity, caspase cleavage products, lactate dehydrogenase (LDH) liberation assays, and a LC3 analysis by western blot. Ultrastructural changes were analysed by electron microscopy of GX15-070-treated cells.

Results

After GX15-070 treatment, the number of viable cells was decreased in all cell lines examined, with IC50 values ranging from 48nM to 3.25 μM. We observed biochemical markers of autophagic cell death and necrosis like LC3 conversion and LDH release after the GX15-070 treatment. Electron microscopy revealed several common characteristic ultrastructural changes like swelling of mitochondria, dilatation of rough endoplasmic reticulum, membrane blebbing and formation of vacuoles. GX15-070 treatment induced DNA fragmentation detected by subG1-peak induction and an arrest in G1 phase of the cell cycle. Caspase activation after GX15-070 incubation was detected but had no effect on viability of cells.

Conclusions

With these experiments we demonstrated the efficacy of the BH3 mimetic drug GX15-070 acting against dedifferentiated thyroid carcinoma cells of various histological origins by the induction of cell death. GX15-070-treated cells underwent non-classical cell death with signs of apoptosis, autophagy and necrosis in parallel. GX15-07 and related compounds thus may be a new therapeutic option for dedifferentiated thyroid carcinoma of various histological subtypes.

Altered epidermal lipid processing and calcium distribution in the KID syndrome mouse model Cx26S17F

The keratitis-ichthyosis-deafness (KID) syndrome is caused by mutations in the gap junctional channel protein connexin 26 (Cx26), among them the mutation Cx26S17F. Heterozygous Cx26S17F mice resemble the human KID syndrome, i.e. exhibiting epidermal hyperplasia and hearing impairments. Newborn Cx26S17F mice show a defective epidermal water barrier as well as altered epidermal lipid secretion and location. Linoleoyl ω-esterified ceramides are strongly decreased on the skin surface of Cx26S17F mice. Moreover, the epidermal calcium gradient is altered in the mutant mice. These alterations may be caused by an abnormal Cx26S17F channel function that leads to a defective epidermal water barrier, which in turn may trigger the hyperproliferation seen in the KID syndrome.

Functional characterization of enzymes catalyzing ceramide phosphoethanolamine biosynthesis in mice

Besides bulk amounts of SM, mammalian cells produce small quantities of the SM analog ceramide phosphoethanolamine (CPE). Little is known about the biological role of CPE or enzymes responsible for CPE production. Heterologous expression studies revealed that SM synthase (SMS)2 is a bifunctional enzyme producing both SM and CPE, whereas SMS-related protein (SMSr) serves as monofunctional CPE synthase. Acute disruption of SMSr catalytic activity in cultured cells causes a rise in endoplasmic reticulum (ER) ceramides, fragmentation of ER exit sites, and induction of mitochondrial apoptosis. To address the relevance of CPE biosynthesis in vivo, we analyzed the tissue-specific distribution of CPE in mice and generated mouse lines lacking SMSr and SMS2 catalytic activity. We found that CPE levels were >300-fold lower than SM in all tissues examined. Unexpectedly, combined inactivation of SMSr and SMS2 significantly reduced, but did not eliminate, tissue-specific CPE pools and had no obvious impact on mouse development or fertility. While SMSr is widely expressed and serves as the principal CPE synthase in the brain, blocking its catalytic activity did not affect ceramide levels or secretory pathway integrity in the brain or any other tissue. Our data provide a first inventory of CPE species and CPE-biosynthetic enzymes in mammals.

Tomographic reconstruction reveals the morphology of a unique cellular organelle, the aggregated macrotubules (Macrotubuli aggregati) of human retinal horizontal cells

Horizontal cells of the human retina contain unique tubular organelles that have a diameter which is about 10 times larger than that of microtubules (~230 nm). These macrotubuli in most cases form regular aggregates. Therefore we propose to introduce them as Macrotubuli aggregati in the Terminologia histologica. Tomographic investigation of the structures revealed that the walls of the tubules most probably consist of intermediate filaments running nearly parallel to each other and show somewhat regularly attached ribosomes on their inner and also outer surface. About 2% of the organelles exhibit double- to multiple layered walls and less than 1% resemble large scrolls. The tubules may extend 10 to over 20 μm in the cytoplasm and are also encountered in soma-near processes extending into the outer plexiform layer. It remains unclear why these structures are only present in humans and few other species and why almost only in horizontal cells. Speculations on possible functions are discussed.

Atypical cell populations associated with acquired resistance to cytostatics and cancer stem cell features: the role of mitochondria in nuclear encapsulation

Until recently, acquired resistance to cytostatics had mostly been attributed to biochemical mechanisms such as decreased intake and/or increased efflux of therapeutics, enhanced DNA repair, and altered activity or deregulation of target proteins. Although these mechanisms have been widely investigated, little is known about membrane barriers responsible for the chemical imperviousness of cell compartments and cellular segregation in cytostatic-treated tumors. In highly heterogeneous cross-resistant and radiorefractory cell populations selected by exposure to anticancer agents, we found a number of atypical recurrent cell types in (1) tumor cell cultures of different embryonic origins, (2) mouse xenografts, and (3) paraffin sections from patient tumors. Alongside morphologic peculiarities, these populations presented cancer stem cell markers, aberrant signaling pathways, and a set of deregulated miRNAs known to confer both stem-cell phenotypes and highly aggressive tumor behavior. The first type, named spiral cells, is marked by a spiral arrangement of nuclei. The second type, monastery cells, is characterized by prominent walls inside which daughter cells can be seen maturing amid a rich mitochondrial environment. The third type, called pregnant cells, is a giant cell with a syncytium-like morphology, a main nucleus, and many endoreplicative functional progeny cells. A rare fourth cell type identified in leukemia was christened shepherd cells, as it was always associated with clusters of smaller cells. Furthermore, a portion of resistant tumor cells displayed nuclear encapsulation via mitochondrial aggregation in the nuclear perimeter in response to cytostatic insults, probably conferring imperviousness to drugs and long periods of dormancy until nuclear eclosion takes place. This phenomenon was correlated with an increase in both intracellular and intercellular mitochondrial traffic as well as with the uptake of free extracellular mitochondria. All these cellular disorders could, in fact, be found in untreated tumor cells but were more pronounced in resistant entities, suggesting a natural mechanism of cell survival triggered by chemical injury, or a primitive strategy to ensure stemming, self-renewal, and differentiation under adverse conditions, a fact that may play a significant role in chemotherapy outcomes.

Nestin(+) tissue-resident multipotent stem cells contribute to tumor progression by differentiating into pericytes and smooth muscle cells resulting in blood vessel remodeling

Tumor vessels with resistance to anti-angiogenic therapy are characterized by the normalization of the vascular structures through integration of mature pericytes and smooth muscle cells (SMC) into the vessel wall, a process termed vessel stabilization. Unfortunately, stabilization-associated vascular remodeling can result in reduced sensitivity to subsequent anti-angiogenic therapy. We show here that blockade of VEGF by bevacizumab induces stabilization of angiogenic tumor blood vessels in human tumor specimen by recruiting Nestin-positive cells, whereas mature vessels down-regulated Nestin-expression. Using xenograft tumors growing on bone-marrow (BM) chimera of C57Bl/6 wildtype and Nestin-GFP transgenic mice, we show for first time that Nestin(+) cells inducing the maturation of tumor vessels do not originate from the BM but presumably reside within the adventitia of adult blood vessels. Complementary ex vivo experiments using explants of murine aortas revealed that Nestin(+) multipotent stem cells (MPSCs) are mobilized from their niche and differentiated into pericytes and SMC through the influence of tumor-cell-secreted factors. We conclude that tissue-resident Nestin(+) cells are more relevant than BM-derived cells for vessel stabilization and therefore have to be considered in future strategies for anti-angiogenic therapy. The identification of proteins mediating recruitment or differentiation of local Nestin(+) cells with potential stem cell character to angiogenic blood vessels may allow the definition of new therapeutic targets to reduce tumor resistance against anti-angiogenic drugs.

Tumor and endothelial cell-derived microvesicles carry distinct CEACAMs and influence T-cell behavior

Normal and malignant cells release a variety of different vesicles into their extracellular environment. The most prominent vesicles are the microvesicles (MVs, 100-1 000 nm in diameter), which are shed of the plasma membrane, and the exosomes (70-120 nm in diameter), derivates of the endosomal system. MVs have been associated with intercellular communication processes and transport numerous proteins, lipids and RNAs. As essential component of immune-escape mechanisms tumor-derived MVs suppress immune responses. Additionally, tumor-derived MVs have been found to promote metastasis, tumor-stroma interactions and angiogenesis. Since members of the carcinoembryonic antigen related cell adhesion molecule (CEACAM)-family have been associated with similar processes, we studied the distribution and function of CEACAMs in MV fractions of different human epithelial tumor cells and of human and murine endothelial cells. Here we demonstrate that in association to their cell surface phenotype, MVs released from different human epithelial tumor cells contain CEACAM1, CEACAM5 and CEACAM6, while human and murine endothelial cells were positive for CEACAM1 only. Furthermore, MVs derived from CEACAM1 transfected CHO cells carried CEACAM1. In terms of their secretion kinetics, we show that MVs are permanently released in low doses, which are extensively increased upon cellular starvation stress. Although CEACAM1 did not transmit signals into MVs it served as ligand for CEACAM expressing cell types. We gained evidence that CEACAM1-positive MVs significantly increase the CD3 and CD3/CD28-induced T-cell proliferation. All together, our data demonstrate that MV-bound forms of CEACAMs play important roles in intercellular communication processes, which can modulate immune response, tumor progression, metastasis and angiogenesis.

7-epi-nemorosone from Clusia rosea induces apoptosis, androgen receptor down-regulation and dysregulation of PSA levels in LNCaP prostate carcinoma cells

The aim of this work was to characterize the antitumoral activity of the plant compound 7-epi-nemorosone in prostate carcinoma cell lines. Prostate cancer is the most frequently diagnosed malignancy and the second-leading cause of cancer death in men. In spite of the current therapeutic options for this cancer entity, many patients die due to metastases in distant organs and acquired chemotherapy resistance. Thus, approaches to provide improvements in outcome and quality of life for such patients are urgently needed. Recently, the polyisoprenylated benzophenone 7-epi-nemorosone, originally collected by honeybees from Clusia rosea and Clusia grandiflora (Clusiaceae), has been described to be a potent antitumoral agent. Here, its activity in prostate carcinoma is reported. 7-epi-nemorosone was isolated from Caribbean propolis employing RP-HPLC techniques. Its cytotoxicity was assessed using the MTT proliferation assay in human androgen-dependent prostate carcinoma LNCaP cells including an MDR1(+) sub-line. No cross-resistance was detected. FACS-based cell cycle analysis revealed a significant increase in the sub-G0/G1, G1, and depletion in the S phase populations. A concomitant down-regulation of cyclins D1/D3 and CDK 4/6 in LNCaP cells was detected by Western blot. Annexin-V-FITC labeling and caspase-3 cleavage assays showed that 7-epi-nemorosone induced apoptotic events. Major signal transduction elements such as p38 MAPK and Akt/PKB as well as androgen receptor AR and PSA production were found to be down-regulated after exposure to the drug. ERK1/2 protein levels and phosphorylation status were down-regulated accompanied by up-regulation but inhibition of the activity of their immediate upstream kinases MEK1/2. Additionally, Akt/PKB enzymatic activity was effectively inhibited at a similar concentration as for MEK1/2. Here, we demonstrate for the first time that 7-epi-nemorosone exerts cytotoxicity in an androgen-dependent prostate carcinoma entity by targeting the MEK1/2 signal transducer.

Lysine-specific demethylase 1 restricts hematopoietic progenitor proliferation and is essential for terminal differentiation

Lysine (K)-specific demethylase 1A (LSD1/KDM1A) has been identified as a potential therapeutic target in solid cancers and more recently in acute myeloid leukemia. However, the potential side effects of a LSD1-inhibitory therapy remain elusive. Here, we show, with a newly established conditional in vivo knockdown model, that LSD1 represents a central regulator of hematopoietic stem and progenitor cells. LSD1 knockdown (LSD1-kd) expanded progenitor numbers by enhancing their proliferative behavior. LSD1-kd led to an extensive expansion of granulomonocytic, erythroid and megakaryocytic progenitors. In contrast, terminal granulopoiesis, erythropoiesis and platelet production were severely inhibited. The only exception was monopoiesis, which was promoted by LSD1 deficiency. Importantly, we showed that peripheral blood granulocytopenia, monocytosis, anemia and thrombocytopenia were reversible after LSD1-kd termination. Extramedullary splenic hematopoiesis contributed to the phenotypic reversion, and progenitor populations remained expanded. LSD1-kd was associated with the upregulation of key hematopoietic genes, including Gfi1b, Hoxa9 and Meis1, which are known regulators of the HSC/progenitor compartment. We also demonstrated that LSD1-kd abrogated Gfi1b-negative autoregulation by crossing LSD1-kd with Gfi1b:GFP mice. Taken together, our findings distinguish LSD1 as a critical regulator of hematopoiesis and point to severe, but reversible, side effects of a LSD1-targeted therapy.

CEACAM1: a key regulator of vascular permeability

Carcinoembryonic antigen cell adhesion molecule-1 (CEACAM1) is an immunoglobulin-like cell surface co-receptor expressed on epithelial, hematopoietic and endothelial cells. CEACAM1 functions as an adhesion molecule, mainly binding to itself or other members of the CEA family. We and others have previously shown that CEACAM1 is crucial for in vivo vascular integrity during ischemic neo-vascularization. Here, we have deciphered the roles of CEACAM1 in normal and pathological vascularization. We have found that Ceacam1−/− mice exhibit a significant increase in basal vascular permeability related to increased basal Akt and endothelial nitric oxide synthase (eNOS) activation in primary murine lung endothelial cells (MLECs). Moreover, CEACAM1 deletion in MLECs inhibits VEGF-mediated nitric oxide (NO) production, consistent with defective VEGF-dependent in vivo permeability in Ceacam1−/− mice. In addition, Ceacam1-null mice exhibit increased permeability of tumor vasculature. Finally, we demonstrate that CEACAM1 is tyrosine-phosphorylated upon VEGF treatment in a SHP-1- and Src-dependent manner, and that the key residues of the long cytoplasmic domain of CEACAM1 are crucial for CEACAM1 phosphorylation and NO production. This data represents the first report, to our knowledge, of a functional link between CEACAM1 and the VEGFR2/Akt/eNOS-mediated vascular permeability pathway.

Terminal nerve in the mouse-eared bat (Myotis myotis): ontogenetic aspects

As in other mammals, ontogenesis of the terminal nerve (TN) in the mouse-eared bat (Myotis myotis) starts shortly after the formation of the olfactory placode, a derivative of the ectoderm. During development of the olfactory pit, proliferating neuroblasts thicken the placodal epithelium and one cell population migrates toward the rostroventral tip of the telencephalon. Here they accumulate in a primordial terminal ganglion, which successively divides into smaller units. Initial fibers of the TN can be distinguished from olfactory fibers in the mid-embryonic period. The main TN fiber bundle (mfb) originates from the anteriormost ganglion in the nasal roof, whereas one or more inconstant smaller fiber bundles (sfb) originate from one or more smaller ganglia in the basal part of the rostral nasal septum. The fibers of the mfb and sfbs join in the posterior quarter of the nasal roof before reaching the central ganglion (M) located in the meninges medial to the olfactory bulb. From the mid-fetal period onward, a thin TN fiber bundle with some intermingled perikarya connects M to the brain by penetrating its wall rostral to the olfactory tubercle. Additional smaller ganglia may occur in this region. The TN and its ganglia persist in postnatal and adult bats but the number of perikarya is reduced here. Moreover, the different potential functions of the TN are discussed briefly.

Analysis of synaptic bodies in the Sprague-Dawley rat pineal gland under extreme photoperiods

Synaptic bodies (SBs) are small, prominent organelles in pinealocytes, most probably involved in signal transduction processes. To check the influence of the photoperiod on their shape plasticity and number we chose two extreme lighting conditions, i.e. 20h of illumination followed by 4h of darkness (LD 20:4) versus (LD 4:20). Pineal glands were assessed at 0, 4 and 13h after dark onset. Under both conditions reconstructed SBs were plates or ribbons but never spheres and there were no obvious differences in morphology. Photoperiodic changes in SB profile size and number were investigated: application of the established method for SB quantification based on single section profile counts (SSPC) of areas showed a significant increase of SB profiles under LD 20:4. However, it has to be noted that SSPC depend on both, number and size of the structures. In contrast to this, modification of the disector counting method, also applied for unbiased quantification of whole SBs, revealed that rat pinealocytes show insignificantly more SBs under LD 20:4 than under 4:20 conditions. The lengths of the SB profiles, which were first measured under different conditions in this study, depend on SB size. They increased significantly under LD 20:4. In conclusion, we detected only an increase in SB size but not in their number. We further prove that, at least for SBs, it is of no value to calculate disector levels from SSPCs.

Identification of a β-Dystroglycan Immunoreactive Subcompartment in Photoreceptor Terminals

PURPOSE

Mutations in the dystrophin-associated glycoprotein complex (DGC) cause various forms of muscular dystrophy. These diseases are characterized by progressive loss of skeletal muscle tissue and by dysfunctions in the central nervous system (CNS). The CNS deficits include an altered electroretinogram, caused by an impaired synaptic transmission between photoreceptors and their postsynaptic target cells in the outer plexiform layer (OPL). The DGC is concentrated in the OPL but its exact distribution is controversial. Therefore, the precise distribution of beta-dystroglycan, the central component of the DGC, within the OPL of the mature chick retina, was determined.

METHODS

Double immunolabeling with antibodies against beta-dystroglycan and against Bassoon, a component of the presynaptic cytomatrix, concentrated at the insertion point of the synaptic ribbon into the active zone of the photoreceptor synapses, showed a nonoverlapping distribution of both proteins within individual rod and cone photoreceptor terminals. The three-dimensional distribution of the DGC within the photoreceptor terminals was determined by reconstruction of the beta-dystroglycan immunoreactivity from serial electron microscopic sections.

RESULTS

We found that beta-dystroglycan was not directly associated with the ribbon synapse but instead concentrated perisynaptically in processes extending from the photoreceptors into the OPL. The processes displayed dystroglycan immunoreactivity primarily along their lateral sides and at their tips. Processes from bipolar or horizontal cells were not labeled.

CONCLUSIONS

The perisynaptic concentration of beta-dystroglycan in photoreceptor terminals suggests a novel domain within photoreceptor terminals with functions in synaptic transmission.

Bizarre alterations of the morphology of pineal synaptic bodies under constant light and an evaluation of suitable 3D-reconstruction software

Three dimensional (3D) reconstruction and modelling software was evaluated to find a procedure suitable for visualization of small subcellular structures in transmission electron microscope images. The method applied in this study demonstrates bizarre alterations of the structure of synaptic bodies (SBs) in pinealocytes of the guinea-pig pineal gland caused by constant illumination. It can, in general, be used for any 3D reconstruction from serial sections. Pineal glands of five guinea-pigs (two kept under a LD cycle of 12:12 h; three kept in constant light, for 4 months) were investigated. SBs consist of an electron-dense centre with attached vesicles. Under normal lighting conditions most SBs are flat plates (about 35 nm in thickness), which eventually may be bent. The proteins comprising the molecular basis of SBs, mainly RIBEYE A and B are polymerised in a regular manner in these plates. This is not the case in other SBs, which appear as spheres or irregular lumps. SBs lie in groups in which usually some of the plates are arranged in parallel arrays Constant illumination caused different changes in morphology: many of the SBs lie in 'paired fields', i.e. appear in groups attached to the cell membranes of two pinealocytes directly opposite to each other. Some of the SBs in such groups are strongly bent, showing blebs and irregular thickened areas, others seem to aggregate and show inclusions of cytoplasm. Further goblet-like, shield-like and other bizarre forms of SBs occurred and the relative number of spheroid and lump-like SBs increased. Protrusions on larger SBs suggest detachment or fusion of SB material to a greater extent than in the control animals. There is a reduction of areas in which the polymerisation of the SB proteins remains well ordered, i.e. where the typical thickness of 35 nm is maintained. It remains unclear why this polymerisation pattern is only partly affected by constant light.

On the use and value of new media and how medical students assess their effectiveness in learning anatomy

The new media have become widely used tools in medical instruction today. But are they regarded as useful by students training to become medical doctors? What are students' most important criteria for a good CD-ROM or valuable Internet resources? To answer these questions, and to obtain definite data on the use of new media, we distributed a questionnaire to preclinical medical and dental students of the Johannes Gutenberg University in Mainz, Germany. The evaluation of 397 questionnaires demonstrates that 94.9% of the students use personal computers; 91.6% of the 85.8% who own a computer have access to the Internet. The Internet is used at least once a week by 70.1% of students for private and by 59.9% for study purposes. Offers of course-relevant material (Workshop Anatomy for the Internet) are of major interest. CD-ROMs with anatomy applications are used by 58.9% of the students. The subjective effectiveness regarding various aspects of learning using books versus CD-ROMs is compared and the students' views of the importance of different features of electronic media are outlined, including course-relevant high-resolution and quality material, key word search, state-of-the-art information, and clearly laid-out tables. The findings of this survey demonstrate high student demand for computer-aided instruction and anatomy applications offered on the Internet and on CD-ROMs. The students' main focus of interest was found to be examination-relevant material and supplemental study material for courses offered locally. The present results may serve as a basis for the development of valuable educational aids.

Teaching and learning gross anatomy using modern electronic media based on the visible human project

This article reviews online (Internet) anatomy projects and multimedia productions (books and CD-ROMs) based on the Visible Human Project (VHP) of the United States National Library of Medicine. The focus of these projects and productions is on the teaching of 3D anatomy using the digitized sections of the visible human male and female. The article also provides information about the VHP, its goals and what it has achieved thus far.

Anatomy online: presentation of a detailed WWW atlas of human gross anatomy--reference for medical education

We present an online anatomy atlas based on the Visible Human Project (VHP) of the US National Library of Medicine. The objective is to provide original unlabeled as well as labeled sections of the human body of high quality and resolution on the Internet, for use in basic and continuing medical education. For a representative overview of the body, 370 axial sections were selected from the male and female data base of the VHP with special regard to regions of clinical interest. Each section is accompanied by its corresponding computer tomography (CT) image and, if available, magnetic resonance images (MRI) for quick and easy comparison of morphologic and radiologic structures. The sections can be studied unlabeled or labeled according to the current Terminologia Anatomica. A linked vocabulary with more than 850 terms explains the labeling. Animations of the sections as well as of CT and MR images allow for further visualization of the topographic relationships of anatomical structures. The responses to the project indicate that students and physicians regard the Internet Atlas of Human Gross Anatomy as a most useful aid for learning and reviewing anatomical details. The atlas is accessible on: http://www.uni-mainz.de/FB/Medizin/Anatomie/workshop/vishuman/Eready.html.

A differential role of CREB phosphorylation in cAMP-inducible gene expression in the rat pineal

In the rat pineal gland cAMP mediates nocturnal induction of the enzyme arylalkylamine N-acetyltransferase (AA-NAT) as well as of transcription factors such as inducible cAMP early repressor (ICER), Fos-related antigen-2 (Fra-2) and JunB. Cyclic AMP stimulates the phosphorylation of the DNA binding protein cAMP response element binding protein (CREB). While cAMP-induced CREB phosphorylation appears to be a prerequisite for AA-NAT and ICER gene expression, it is not known whether CREB phosphorylation accounts for the full cAMP response of the two genes. Furthermore, the significance of CREB phosphorylation in cAMP-activated Fra-2 and JunB transcription is unknown. In the present in vitro study we used the serine/threonine protein phosphatase inhibitor okadaic acid (OA) to phosphorylate CREB without altering intrapineal cAMP concentration. It was observed that OA (10(-7) M) was less effective than dibutyryl cAMP (dbcAMP; 10(-3) M) in inducing AA-NAT mRNA and ICER mRNA, respectively. On the basis of this finding, it is concluded that CREB phosphorylation alone is apparently not sufficient for the full cAMP response of the two genes. By contrast, OA and dbcAMP equally stimulated the accumulation of the mRNAs of Fra-2 and JunB. Therefore cAMP may induce Fra-2 and JunB transcripts via CREB phosphorylation. Our observations suggest that CREB phosphorylation plays a critical role in diversification of cAMP-dependent gene induction in the rat pineal.

Unilateral absence of the terminal nerve and distribution of gonadotropin-releasing hormone immunoreactive neurons in the brain of the common mole-rat (Cryptomys, Rodentia)

A paired terminal nerve with gonadotropin-releasing hormone-immunoreactive (GnRHir) neurons was found in five of six specimens of the Zambian common mole-rat (Cryptomys sp.). In these animals the distribution of GnRHir neurons in the CNS was approximately even on both sides. One adult female lacked a right terminal nerve, yet exhibited a comparable total number of GnRHir neurons, most of which were located on the left side of the brain, i. e., on that side where the terminal nerve was present. An additional population of GnRHir cells was detected in the area of the parafascicular and dorsomedial thalamic nuclei of three non-reproductive adult females, but not in young animals (one female, two males). The additional GnRHir cells, referred to as dark spot cells (DSCs) since their perikarya exhibit large or small strongly immunoreactive vacuoles, were present on both sides of the brain in equal numbers even in the specimen with unilateral absence of the terminal nerve. Obviously, the lack of one terminal nerve correlates with a drastic reduction in the number of ipsilateral genuine neurons but leaves the DSCs unaffected.

The innervation of taste buds in the soft palate and circumvallate papilla of the rat as revealed by the zinc iodide-osmium tetroxide technique

The taste buds in the soft palate and the circumvallate papillae of the rat were investigated by the zinc iodide-osmium tetroxide technique. In addition, electron micrographs of taste buds stained with this method were presented for the first time. Differences in taste bud structures were found between the examined regions. The taste buds of the soft palate showed a complicated plexus of intragemmal nerve fibers. Some fibers exhibited terminal polymorphic swellings. Single branches could be traced close to the space of the taste pore. In the soft palate, the taste bud cells remained unstained, whereas in the circumvallate papillae of the tongue, a subpopulation of taste bud cells could be selectively stained and the intragemmal nerve fibers were characterized by large varicosities. The morphological dissimilarities between the taste buds of the investigated regions might be explained by their functional characteristics, or possibly their varying affinities to the taste qualities. Electron microscopic investigation of the stained circumvallate papillae revealed that the electron-dense reaction product had primarily accumulated in a subpopulation of light cells. Dark cells exhibited only a slight labelling. In detail, the precipitate was found loosely distributed in the cytoplasm as well as the nuclei of the cells, and particularly concentrated at the membranes of light vacuoles, this probably being profiles of dilated endoplasmic reticulum. A few roundish accumulations of precipitate were seen in the cytoplasm of taste bud cells, which showed no intensive light microscopic staining. Labelled material was also found within the taste pores outside the apical processes of the cells. The present findings indicate that the zinc iodide-osmium tetroxide technique is applicable to neuroanatomical studies of taste buds.

Adaptation of the disector method to rare small organelles in TEM sections exemplified by counting synaptic bodies in the rat pineal gland

The disector is the only objective method for quantifying particles of variable size in a given volume. With this method, cell organelles are identified on adjacent sections, but only those present in one section are counted. When counting extremely rare structures in transmission electron microscope sections (physical disector), the usual procedure of counting on electron micrographs is limited for economic reasons (e.g. micrographs highly outnumbering the investigated structures). Hence, to apply this unbiased stereological method, a modification of the physical disector concerning 3 aspects has been developed. (1) The prerequisite of screening large corresponding tissue areas (here approximately 65000 microm2) was fulfilled by examining tissue areas along the edges of ultrathin sections. (2) The size of the counting frame was determined by measuring the lengths of the section margins (minus a guard area) by means of a Morphomat. This value was multiplied by the width of the investigated tissue zone, corresponding to the diameter of the electron microscope viewing screen. (3) Disector counting was carried out simultaneously on both sections (bidirectional disector) to improve efficiency. In the present study tiny synaptic bodies (SBs) were quantitated by disector in a rat pineal gland, yielding approximately 30 SBs/1000 microm3. By contrast, single section profile counts of SBs amounted to 90 SBs/20000 microm2. Since the presently described adaptation of the disector is time-consuming, it is proposed to determine a proportion factor allowing to estimate number of structures per volume based on single section profile counts. This would decrease the evaluation time by more than 50%.

The shape of synaptic ribbons in the rat pineal gland

Under the transmission electron microscope, synaptic ribbons (SRs) of the mammalian pineal gland appear as rod-like organelles. Their three-dimensional structure is not precisely known. In the present study, pineal SRs were investigated using serial sections obtained from rats killed at noon and midnight. The shape of the SRs was reconstructed based on SR profile length and the number of sections in which the profiles were contained. The results obtained show that SRs are basically flat plate-like structures with polymorphic lateral edges. Reconstructions of SRs revealed that they had average dimensions of 300x150x35 nm and were 19.3% larger at night than at day; the difference in SR size points to perhaps major differences in synaptic function between day and night.