Phosphorylation of the compartmentalized PKA substrate TAF15 regulates RNA-protein interactions

Spatiotemporal-controlled second messengers alter molecular interactions of central signaling nodes for ensuring physiological signal transmission. One prototypical second messenger molecule which modulates kinase signal transmission is the cyclic-adenosine monophosphate (cAMP). The main proteinogenic cellular effectors of cAMP are compartmentalized protein kinase A (PKA) complexes. Their cell-type specific compositions precisely coordinate substrate phosphorylation and proper signal propagation which is indispensable for numerous cell-type specific functions. Here we present evidence that TAF15, which is implicated in the etiology of amyotrophic lateral sclerosis, represents a novel nuclear PKA substrate. In cross-linking and immunoprecipitation experiments (iCLIP) we showed that TAF15 phosphorylation alters the binding to target transcripts related to mRNA maturation, splicing and protein-binding related functions. TAF15 appears to be one of multiple PKA substrates that undergo RNA-binding dynamics upon phosphorylation. We observed that the activation of the cAMP-PKA signaling axis caused a change in the composition of a collection of RNA species that interact with TAF15. This observation appears to be a broader principle in the regulation of molecular interactions, as we identified a significant enrichment of RNA-binding proteins within endogenous PKA complexes. We assume that phosphorylation of RNA-binding domains adds another layer of regulation to binary protein-RNAs interactions with consequences to RNA features including binding specificities, localization, abundance and composition.

Toll-Like Receptor 3 Mediates Aortic Stenosis Through a Conserved Mechanism of Calcification

BACKGROUND

Calcific aortic valve disease (CAVD) is characterized by a phenotypic switch of valvular interstitial cells to bone-forming cells. Toll-like receptors (TLRs) are evolutionarily conserved pattern recognition receptors at the interface between innate immunity and tissue repair. Type I interferons (IFNs) are not only crucial for an adequate antiviral response but also implicated in bone formation. We hypothesized that the accumulation of endogenous TLR3 ligands in the valvular leaflets may promote the generation of osteoblast-like cells through enhanced type I IFN signaling.

METHODS

Human valvular interstitial cells isolated from aortic valves were challenged with mechanical strain or synthetic TLR3 agonists and analyzed for bone formation, gene expression profiles, and IFN signaling pathways. Different inhibitors were used to delineate the engaged signaling pathways. Moreover, we screened a variety of potential lipids and proteoglycans known to accumulate in CAVD lesions as potential TLR3 ligands. Ligand-receptor interactions were characterized by in silico modeling and verified through immunoprecipitation experiments. Biglycan (Bgn), Tlr3, and IFN-α/β receptor alpha chain (Ifnar1)-deficient mice and a specific zebrafish model were used to study the implication of the byglycan (BGN)-TLR3-IFN axis in both CAVD and bone formation in vivo. Two large-scale cohorts (GERA [Genetic Epidemiology Research on Adult Health and Aging], n=55 192 with 3469 aortic stenosis cases; UK Biobank, n=257 231 with 2213 aortic stenosis cases) were examined for genetic variation at genes implicated in BGN-TLR3-IFN signaling associating with CAVD in humans.

RESULTS

Here, we identify TLR3 as a central molecular regulator of calcification in valvular interstitial cells and unravel BGN as a new endogenous agonist of TLR3. Posttranslational BGN maturation by xylosyltransferase 1 (XYLT1) is required for TLR3 activation. Moreover, BGN induces the transdifferentiation of valvular interstitial cells into bone-forming osteoblasts through the TLR3-dependent induction of type I IFNs. It is intriguing that Bgn^-/-, Tlr3^-/-, and Ifnar1^-/- mice are protected against CAVD and display impaired bone formation. Meta-analysis of 2 large-scale cohorts with >300 000 individuals reveals that genetic variation at loci relevant to the XYLT1-BGN-TLR3-interferon-α/β receptor alpha chain (IFNAR) 1 pathway is associated with CAVD in humans.

CONCLUSIONS

This study identifies the BGN-TLR3-IFNAR1 axis as an evolutionarily conserved pathway governing calcification of the aortic valve and reveals a potential therapeutic target to prevent CAVD.

Distal radius fracture fixation with volar locking plates and additional bone augmentation in osteoporotic bone: a biomechanical study in a cadaveric model

BACKGROUND

Fractures of the distal radius represent the most common fractures in adults. Volar locked plating has become a popular method for treating these fractures, but has been subject to several shortcomings in osteoporotic bone, such as loss of reduction and screw purchase. In order to overcome these shortcomings, cement augmentation has been proposed.

METHODS

AO-type 23-A3.3 fractures were made in 8 pairs of fresh frozen osteoporotic cadaveric radial bones. All specimens were treated with volar plating, and divided into cement augmentation or non-augmentation groups (n = 8/group). Constructs were tested dynamically and load to failure, construct-stiffness, fracture gap movement and screw cutting distance were measured.

RESULTS

Cement augmentation resulted in a significant increase in cycles and load to failure, as well as construct stiffness at loads higher than 325 N. When compared to the non-augmented group, fracture gap movement decreased significantly at this load and higher, as did screw cutting distance at the holes of the ulnar column. The cycles to failure depend on the BMD in the distal region of the radius.

CONCLUSION

Cement augmentation improves biomechanical properties in volar plating of the distal radius.

Influence of short-term exposure to airborne Der p 1 and volatile organic compounds on skin barrier function and dermal blood flow in patients with atopic eczema and healthy individuals

BACKGROUND

Epidemiological studies indicate environmental pollutants to be involved in the increase in the prevalence of allergic diseases. In human exposure studies, volatile organic compounds (VOCs) have been shown to cause exacerbations of allergic asthma whereas, no data concerning atopic eczema (AE) are available.

OBJECTIVE

We investigated the effect of airborne VOCs on the skin of patients with AE and controls in the presence or absence of house dust mite allergen, Der p 1.

METHODS

In a double-blind crossover study, 12 adults with AE and 12 matched healthy volunteers were exposed on their forearms to Der p 1 and subsequently to a mixture of 22 VOCs (M22, 5 mg/m(3)) in a total body exposure chamber for 4 h. Transepidermal water loss (TEWL) and skin blood flow were measured in all subjects before, during and after exposure. Additionally, an atopy patch test (APT) with Der p 1 was applied to the skin after exposure.

RESULTS

A significant increase in transepidermal water loss was observed 48 h after exposure to VOCs as compared with exposure with filtered air in all individuals (mean difference: +34%; 95% Confidence Interval: 7-69%). Prior Der p 1 exposure resulted in a significant rise of dermal blood flow after 48 h in patients with AE but not in controls. Six out of seven patients showed enhanced atopy patch test (APT) reactions to HDM allergen after previous exposure to VOCs.

CONCLUSION

Our results show that exposure to VOCs - at concentrations commonly found in indoor environments - can damage the epidermal barrier and enhance the adverse effect of Der p 1 on sensitized subjects with AE. These findings may contribute to a better understanding of the mechanisms underlying the increase in prevalence and exacerbation of AE.

Gastroduodenal tolerability of lumiracoxib vs placebo and naproxen: a pilot endoscopic study in healthy male subjects

BACKGROUND

Lumiracoxib (Prexige) is a cyclooxygenase-2 (COX-2) selective inhibitor.

AIM

To compare the gastroduodenal tolerability of lumiracoxib with placebo and naproxen in a randomized, parallel-group, double-blind study.

METHODS

: Sixty-five healthy male subjects were randomized to receive 8 days' dosing with lumiracoxib 200 mg twice daily (b.d.) (n = 21), placebo (n = 22) or naproxen 500 mg b.d. (n = 22). Endoscopic evaluations of gastric and duodenal mucosae were conducted at baseline and after 8 days' dosing. Serum was assayed for ex-vivo concentrations of thromboxane B2 (TxB2) to determine cyclooxygenase-1 (COX-1) inhibitory activity.

RESULTS

Sixty subjects (20 per group) completed the study. No gastroduodenal erosions were observed in subjects receiving lumiracoxib. Thirteen subjects receiving naproxen developed duodenal erosions. At the gastric site, one subject in each of the naproxen and placebo groups had erosions; one subject receiving naproxen also developed a small asymptomatic gastric ulcer. Gastrointestinal adverse events accounted for 42.3% of all adverse events, occurring in 3/21, 4/22 and 6/22 of the lumiracoxib, placebo and naproxen groups, respectively. TxB2 levels were similar for patients receiving placebo or lumiracoxib, but were reduced by > 95% in patients receiving naproxen, compared with placebo.

CONCLUSIONS

Multiple doses of lumiracoxib resulted in gastroduodenal tolerability similar to placebo and superior to naproxen.

Microspectroscopy and imaging in the THz range using coherent CW radiation

A novel THz near-field spectrometer is presented which allows the performance of biological and medical studies with high spectral resolution combined with a spatial resolution down to lambda/100. In the setup an aperture much smaller than the used wavelength is placed in the beam very close to the sample. The sample is probed by the evanescent wave behind the aperture. The distance is measured extremely accurately by a confocal microscope. We use monochromatic sources which provide powerful coherent cw radiation tuneable from 50 GHz up to 1.5 THz. Transmission and reflection experiments can be performed which enable us to study solids and molecules in aqueous solution. Examples for spectroscopic investigations on biological tissues are presented.

Immunostaining of human autopsy aortas with antibodies to modified apolipoprotein B and apoprotein(a)

A systematic immunohistochemical study of different stages of atherosclerosis in human aortas was performed using several antibodies. Because oxidation of lipoproteins could be a key event in atherogenesis, an antibody against apolipoprotein B (apoB) from low-density lipoprotein (LDL) modified with the lipid peroxidation-specific aldehyde, 4-hydroxynonenal (4-HNE) (anti-4-HNE-apoB), was raised in rabbits. This antibody recognizing 4-HNE protein adducts was used in concert with an antibody to apo(a) from lipoprotein(a), considered also potentially atherogenic, as well as with an antibody and a monoclonal antibody (mAb) to apoB. Autopsy material from 12 corpses was investigated. The immunohistochemical investigation by the alkaline-phosphatase technique included control specimens regarding postmortem artifacts by autolysis and oxidation. The results from six specimens from five corpses are presented. A positive staining with the antibody to apoB but not with anti-4-HNE-apoB was seen in the normal intima. The thickened intima of early, transitional, and advanced atherosclerotic lesions and atheromata showed a predominantly extracellular staining with all antibodies and the applied mAb. To test the specificity of the staining, antibodies preadsorbed by the appropriate antigens and nonimmune sera were used, giving negative results. These findings indicated a colocalization of epitopes derived from lipid peroxidation of polyunsaturated fatty acids and epitopes specific for apoB and apo(a) during atherogenesis in humans.

Multifocal fibrosclerosis. Report of a case of bilateral idiopathic sclerosing pseudotumor and retroperitoneal fibrosis

We describe a 56-year-old white man who presented with gradual and progressive visual loss and subsequent hypertension and pedal edema. A computed tomographic scan of the orbits showed bilateral diffuse retrobulbar masses, and an abdominal computed tomographic scan showed a diffuse retroperitoneal mass invading the aorta, ureters, and inferior vena cava. Biopsies of the orbit and abdomen confirmed a heterogeneous cell population and marked fibrosis consistent with a sclerosing inflammatory process. Bilateral sclerosing orbital inflammatory disease should cue the physician to suspect coexisting systemic disease. This report is the fourth to document bilateral sclerosing orbital inflammatory disease and the second to have obtained biopsies of the orbit and abdomen showing histologic similarities.

Immunohistochemical detection of tumor necrosis factor-alpha, other cytokines and adhesion molecules in human livers with alcoholic hepatitis

This immunohistochemical study was designed to investigate the possible contribution to and topographical distribution of some important cytokines, such as tumour necrosis factor alpha (TNF alpha) and interleukins, in acute alcoholic hepatitis. The well-known inductive capacity of these cytokines with respect to the expression and/or up-regulation of adhesion molecules, such as intercellular adhesion molecule-1 (ICAM-1) and endothelial leukocyte adhesion molecule-1 (ELAM-1), was a further point to be studied. Moreover, the proposed induction of adhesion molecules might also be associated with the activation and attraction of a special population of inflammatory cells characteristic for alcoholic hepatitis. Frozen liver samples from patients who died with signs of acute alcoholic hepatitis were evaluated using the alkaline phosphatase anti-alkaline phosphatase immunostaining technique and also single and double indirect immunofluorescence. In acute alcoholic hepatitis TNF alpha could be detected predominantly in ballooned hepatocytes, which often contained alcoholic hyalin (Mallory bodies). Moreover, TNF alpha showed a co-distribution with ICAM-1 expressed in the membranes of hepatocytes and with the occurrence of CD11b positive polymorphonuclear leukocytes (neutrophils) suggesting a possible major role of the beta 2-integrin Mac-1 as a ligand for ICAM-1. No induction of ELAM-1 could be found. In alcoholic hepatitis cytokines may be responsible for the induction of the adhesion molecule ICAM-1 on hepatocytic membranes and activate a defined population of inflammatory cells, thus contributing to the characteristic histological picture of acute alcoholic hepatitis with its concentration of neutrophils especially in areas with ballooned Mallory body-containing hepatocytes. Our results are in line with clinical findings showing high levels of TNF alpha and interleukin-1 in sera of patients with alcoholic hepatitis and with the already reported expression of ICAM-1 on hepatocytes.

Cryopreservation of cytological specimens for immunocytochemistry

A method has been established for storage and preservation of cytological specimens in liquid nitrogen and further processing for immunocytochemistry as smears prepared from thawed cells or cryo-sections of frozen cell pellets. For the experiments cultured cells of a T-lymphoblastic leukemia cell line (ATCC CCL 119) and blood cells of the buffy coat of healthy humans were treated with a cryo-solution (fetal calf serum +5% dimethylsulfoxid) and after freezing stored in liquid nitrogen. Alternatively, cells preincubated with cryo-solution followed by suspension in fetal calf serum without cryo-additive were frozen and stored in liquid nitrogen for the production of cryo-sections. Indirect immunofluorescence and alkaline phosphatase--antialkaline phosphatase based immunoreactions were performed for the decoration of various surface antigens with a panel of monoclonal antibodies. All immunoreactions were repeated at least three times and the stored cell preparations were investigated after different periods of storage (up to four months). The immunoreactions of fresh cells in suspension (which were used as controls) were comparable with those of cryopreserved cells, e.g. cells on smears after thawing and on cryo-sections of cell pellets. The strongest immunoreactions were achieved on fixed cryo-sections. The maintenance of cell morphology of smears from cryopreserved cells was slightly better than of cells from cryo-sections. In our hands the preparation of cell pellets, which are suitable for the storage in liquid nitrogen and the production of cryosections, is a very useful method for immunocytochemical investigations of cytological specimens especially in situations where immunoreactions cannot be performed on fresh material.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcoholic liver disease. Parenchyma to stroma relationship in fibrosis and cirrhosis as revealed by three-dimensional reconstruction and immunohistochemistry

Severe ethanol-induced liver damage is characterized by fibrous dissociation of liver cell plates leading to many apparently isolated hepatocytes. Three-dimensional reconstruction, however, revealed hepatocytes that were surrounded by connective tissue as endpoints of "parenchymal pillars" or in association with liver cell plates and bile ductules. Double immunofluorescence studies displayed the expression of cytokeratin (CK) 7 in bile ducts, including bile ductules, but also in some hepatocytes still organized in liver cell plates. The other bile duct, typical CK, namely CK 19, was only detectable in few hepatocytes. However, the expression of CK 7 and/or CK 19 was less frequent in hepatocytes that were closely associated with bile ductules. CK 7 and CK 19 were also found in some, but not all, Mallory bodies. These observations indicate that the expression of these two CKs is neither related to a transformation of hepatocytes to bile duct-like structures ("ductal metaplasia") nor to the formation of Mallory bodies. Furthermore, double immunofluorescence studies revealed small groups of hepatocytes and bile ductules that were encircled by basement membrane material, thus suggesting the formation of "secretory units."

Intraoperative surgical specimen evaluation: frozen section analysis, cytologic examination, or both? A comparative study of 206 cases

Having recently become aware of the merits of cytologic preparations, histopathologists are focusing their attention on cytologic examination as a means of intraoperatively evaluating surgical specimens. This study compares the diagnostic accuracy and quality of frozen-section (FS) and cytologic preparations from 206 surgical specimens. The quality of cytologic preparations was significantly superior to that of FSs (P = 0.0001). With the use of a three-level accuracy scale suited to the practical demands of intraoperative evaluation, there was no significant difference between the accuracy of diagnosis by FS analysis compared with that achieved by cytologic examination (P = 0.35). More importantly--except in one case--whenever one technique did not correctly distinguish benign from malignant disease, the other technique yielded an essentially correct diagnosis. With the use of both techniques, 99.5% of cases were interpreted correctly, at least in regard to benign versus malignant diagnoses. Because significant additional time, equipment, stains, laboratory space, or personnel are not needed to implement intraoperative cytologic studies in a routine anatomic pathology laboratory, the authors advocate the simultaneous use of FS and cytologic studies in the specified context.

Co-expression of cytokeratin and vimentin filaments in rete testis and epididymis. An immunohistochemical study

In 11 testes of different developmental stages (from 10-week-old embryos to adult) the cytokeratin and vimentin expression patterns of rete testis and epididymis were investigated immunohistochemically in formaldehyde-fixed paraffin-embedded material. In addition, immunofluorescence microscopy including double immunofluorescence was performed on frozen sections of 3 of these 11 cases. Rete testis and epididymis cells displayed a heterogeneous co-expression of cytokeratin and vimentin. In double immunohistochemistry, differences in distribution of keratin and vimentin intermediate filaments with predominance of cytokeratins in the apical cytoplasmic regions and of vimentin filaments in the basal portions of the cells were found. Cytokeratin expression preceded the appearance of vimentin: cytokeratin was already detectable in 10-week-old embryos, while weak vimentin immunoreactivity was first seen in 12-week-old embryos and became conspicuous in testes around the perinatal period. In testes of children up to 2 years of age the cytoplasmic distribution of cytokeratin and vimentin was more homogeneous. Predominance of the basal cell portions for vimentin and the apical regions for cytokeratin staining were less pronounced than in adult testes. In the proximal and distal parts of the epididymis a different intermediate filament expression pattern was found with a clear predominance of cytokeratin near the rete.

Benign neurilemmoma (schwannoma) masquerading as a pleomorphic adenoma of the submandibular salivary gland

A case of solitary benign neurilemmoma (schwannoma) arising in the submandibular region is presented. The tumor was mistaken clinically for an enlarged submandibular salivary gland. Fine needle aspiration cytology made an erroneous diagnosis of a pleomorphic adenoma, predominantly stromal in composition. Histology of the resection specimen resulted in the correct diagnosis of a benign schwannoma. Review of the needle aspirate demonstrated cytologic features that should enable both the correct diagnosis of this neoplasm and its distinction from pleomorphic adenoma, which it mimicked in this location.

Curschmann's spirals and actinomycosis in a fine needle aspirate of the parotid

Fine needle aspiration (FNA) of bilaterally enlarged submandibular salivary glands yielded both Curschmann's spirals and actinomycetes filaments in the FNA smears. Histologic study of specimens from the bilateral submandibulectomy confirmed the actinomycosis but failed to demonstrate the presence of spirals. The presence of Curschmann's spirals in FNA material is a finding not previously described in the English literature. Actinomycosis, although well documented in exfoliative cytology, has been rarely reported in fine needle aspirates. This unique case afforded the opportunity of illustrating the characteristic features of Curschmann's spirals and actinomycetes colonies, as well as reviewing the etiology and pathogenesis of Curschmann's spirals, in FNA material.

Fine needle cytology--is aspiration suction necessary? A study of 100 masses in various sites

One hundred consecutive superficial mass lesions in various body sites were sampled by both conventional fine needle aspiration (FNA) and by a fine needle without the application of syringe suction. The latter technique is based on the principle of capillarity and may be termed "fine needle capillary" (FNC) sampling. The two sampling techniques were compared using five objective parameters: (1) the amount of diagnostic cellular material present, (2) the retention of appropriate architecture and cellular arrangement, (3) the degree of cellular degeneration, (4) the cellular trauma and (5) the volume of obscuring background blood and clots. There was no statistically significant difference between the efficacies of the two sampling techniques for any of the parameters studied. FNA sampling was diagnostic in a greater number of cases than was FNC sampling, but this difference was not statistically significant at a level of P = .05. When FNC sampling was diagnostic, it more frequently produced superior-quality material; conventional FNA, although diagnostic in a greater number of cases, mostly produced adequate, rather than superior-quality, material. This trend was not, however, statistically significant at a level of P = .05. These findings differ from those of previous studies (which have shown overall superiority of FNC sampling over conventional FNA sampling) and suggest that the technique of fine needle sampling employed for cytodiagnosis can be left to the personal preference of the operator.

Aspiration cytology of neuroendocrine tumors below the diaphragm

In a series of 630 transabdominal fine-needle aspirates, 24 neuroendocrine tumors (NETs) presenting below the diaphragm were encountered. Of these, 10 were classic small-cell undifferentiated carcinomas (SCUCs). Recognition of SCUC in abdominal aspirates has major directive value, pointing to bronchogenic origin, possibly unsuspected, in most cases (eight of 10 in this series). The other 14 NETs were 10 pancreatic islet-cell tumors and four intestinal carcinoids, both diagnosed more frequently in metastatic than in primary sites (10 of 14 in the liver in this series). The cytologic presentation of these non-SCUC neoplasms has received little literature attention, and it is described and illustrated here, with discussion of cytologic pitfalls and differential diagnoses. Diagnostic specificity was 100%, and sensitivity was also 100%, exclusive of two sampling errors. The purpose of this article is to establish a broader view of the range of morphological features of the extended neuroendocrine group of tumors in aspiration cytology.

Small cell undifferentiated carcinoma of the parotid gland. Cytologic, histologic, immunohistochemical and ultrastructural features of a neuroendocrine variant

A case of primary small cell undifferentiated carcinoma (SCUC) of the parotid gland, diagnosed initially by fine needle aspiration (FNA) cytology and confirmed by histology, immunohistochemistry and transmission electron microscopy (TEM), is presented. The FNA cytologic features that enabled an accurate diagnosis of this rare salivary gland tumor included nuclear granularity and markedly angular nuclear molding of numerous small cells that were usually present as large syncytia in an inflammatory background. Numerous mitotic figures were also present in this vascular lesion. These features were also evident in the surgical specimens. Immunohistochemistry demonstrated neuron-specific enolase positivity while TEM demonstrated intracytoplasmic neurosecretory granules in this case, indicating a neuroendocrine derivation for this neoplasm instead of the more usual origin of salivary gland SCUCs in ductal epithelial or myoepithelial tissue.

Fine needle aspiration cytology of parotid sarcoidosis

Granulomatous lesions of the salivary gland are rare; as such, there have been few reports of the cytologic features of granulomatous sialadenitis in general, and salivary gland sarcoidosis in particular. A case of systemic sarcoidosis involving both parotid glands, diagnosed initially by fine needle aspiration (FNA) cytology, is presented. The specific cytologic features included histiocytes of both epithelioid and giant multinucleated types, without background necrosis. The FNA cytologic differential diagnosis of bilateral parotitis is discussed.

Fine needle aspiration cytology of mucinous cystadenocarcinoma of the pancreas. Further observations

Mucinous cystadenocarcinoma of the pancreas is among the few potentially curable malignancies of this organ; recognition of the differences between this and other pancreatic tumors is thus of paramount importance. A second example of mucinous cystadenocarcinoma of the pancreas diagnosed by fine needle aspiration, performed under ultrasonographic guidance, is presented, emphasizing both the radiographic distinction from other cystic lesions plus cytologic features not previously stressed. In essence, the cytodiagnosis relies less on cell morphology, which is characteristically bland and relatively monomorphic, than on the presence of extracellular mucin, which must be distinguished from amorphous background material and necrotic debris. The possibility of diagnosing benign mucinous and serous cystadenomas by imaging and cytology is addressed.