Immune-camouflaged graphene oxide nanosheets for negative regulation of phagocytosis by macrophages.

Signal regulatory protein alpha (SIRPα) is highly expressed in macrophages of the reticuloendothelial system and in tumor-associated macrophages, whereas tumor cells express the surface membrane protein, CD47, which interacts with SIRPα to negatively regulate phagocytosis. In this study, we modified the surfaces of graphene oxide (GO) nanosheets with a CD47-like SIRPα-binding peptide (SP). The presence of SP on GO nanosheets reduced the macrophage uptake to a greater extent than the PEGylation of such nanosheets. This reduced uptake was found to be mediated by the activation of Src homology region 2 domain-containing phosphatase 1 (SHP-1) and the downstream inhibition of myosin assembly, which is necessary for phagosome formation. Unlike SP-coated GO nanosheets, PEGylated GO nanosheets did not affect myosin assembly or phagocytosis. After in vivo systemic administration, the clearance of SP-coated GO nanosheets was slower than that of PEGylated GO nanosheets, and this difference increased with repeated administration. Finally, SP-coated GO nanosheets showed a higher distribution to tumor tissues than PEGylated GO nanosheets or a physical mixture of SP and GO nanosheets. Our findings indicate that immune-camouflaged GO nanosheets with natural CD47-like SIRPα-binding molecules can reduce the nonspecific loss of such nanosheets through macrophage uptake, thereby enhancing their blood circulation and tumor delivery after multiple injections.

Paraneoplastic pemphigus without an underlying neoplasm.

We describe a 52-year-old man with paraneoplastic pemphigus (PNP) without any evidence of an underlying neoplasm over an 8-year follow-up period. He had a chronic relapsing vesiculobullous eruption for approximately 7 years (from April 1998 to May 2005). Initially, scattered flaccid vesicles with crusts developed on the face and trunk, which waxed and waned several times. Our patient was diagnosed as having PNP based on immunopathological criteria for PNP, i.e. histopathological, immunoblotting and immunoprecipitation analyses. However, physical and laboratory examinations including serial blood tests with peripheral blood smear, whole-body positron emission tomography/computed tomography and abdominal ultrasound were unable to detect any underlying neoplasm over an 8-year follow-up period.

Sera from patients with toxic epidermal necrolysis contain autoantibodies to periplakin.

BACKGROUND: The pathophysiological mechanism of toxic epidermal necrolysis (TEN) with extensive bullae that is induced suddenly by drugs is not well understood. The individual patterns and distribution of the widespread mucocutaneous reactions of TEN often show striking similarities with those of paraneoplastic pemphigus (PNP), which is known to involve autoantibodies (aAbs) to members of the plakin family. OBJECTIVES: To investigate the existence of circulating aAbs to periplakin in the sera of patients with TEN. METHODS: The presence of circulating aAbs to periplakin was examined using immunoblotting, immunoabsorption and indirect immunofluorescence (IF) analyses. Recombinant protein expression was used to determine the interaction between periplakin and aAbs in the sera of patients with TEN. RESULTS: Indirect IF studies revealed circulating aAbs in the intercellular area in the epidermis. Interestingly, on rat bladder the staining pattern of the IgG deposits was similar to that observed in patients with PNP. Immunoblotting analysis of the epidermal extracts was used to identify the aAbs in the sera of patients with TEN. These contained circulating aAbs to a 190-kDa protein corresponding to periplakin. Recombinant periplakin and domains of periplakin were prepared in order to confirm the existence of aAbs to periplakin. Immunoblotting with these proteins demonstrated that the sera from patients with TEN reacted with each domain as well as with the full-length periplakin. CONCLUSIONS: We found that circulating aAbs in the sera of patients with TEN target periplakin. These aAbs might play a role in the pathogenesis of TEN as a humoral autoimmune mechanism.

Tob is a potential marker gene for the basal layer of the epidermis and is stably expressed in human primary keratinocytes.

BACKGROUND: Epidermis consists of multiple layers, from the proliferating basal layer to terminal differentiated cornified layers, and these layers are defined by differentiation status. Tob gene product is known to be a member of the BTG antiproliferative protein family. We investigated the expression pattern of Tob gene product to understand the possible role in differentiation of keratinocytes and epidermis. OBJECTIVES: In this study, we examined the expression of Tob gene product in the primary cultured human keratinocytes and in the in vivo epidermis. METHODS: The expression of Tob gene product was assessed by Western blotting analysis. Cellular localization of Tob was detected using the green fluorescent protein-tagged Tob cDNA expression construct. In vivo expression of Tob gene product in the epidermis was determined by immunohistochemistry with paraffin sections. RESULTS: Tob family members are degraded by the ubiquitine-proteasome system triggered by the growth signal. Tob is stably and abundantly expressed in primary cultured human keratinocytes. Furthermore, the expression of Tob in the keratinocytes persists during the differentiation induced by calcium; however, it was not detected in primary cultured fibroblasts. Also, the subcellular localization of Tob is mainly in the cellular membrane in the primary human keratinocytes. We evaluated Tob expression in normal skin, oral mucosa and different diseases, such as psoriasis, X-linked ichthyosis and squamous cell carcinoma (SCC). Using immunohistochemical analysis, we observed that Tob was selectively expressed in the basal layer of X-linked ichythyosis and the hyperproliferative basal layer of psoriasis and oral mucosa as well as in normal epidermis. In SCC, the expression of Tob gene product was relatively decreased. CONCLUSIONS: Tob is stably expressed in primary human keratinocytes and it is specifically expressed in the basal layer of in vivo epidermis.

Phosphorylation of murine homeodomain protein Dlx3 by protein kinase C.

The Dlx3 homeodomain gene is expressed in terminally differentiated murine epidermal cells. As demonstrated for differentiation-specific granular markers, Dlx3 is activated in primary mouse keratinocytes cultured in vitro by increasing the level of the extracellular Ca(2+). This activation is mediated through a protein kinase C-dependent (PKC) pathway. In this study, we investigated whether PKC can modulate the activity of murine Dlx3 protein. Using in vitro kinase assays, we show that PKC enzymes phosphorylate the Dlx3 protein. Using keratinocyte nuclear extracts for the kinase reaction, we determined that Dlx3 protein is phosphorylated, and the phosphorylation is inhibited by the PKC-specific inhibitor GF109203X, suggesting that Dlx3 is phosphorylated by PKC in vivo. Of the PKC isoforms present in the epidermis, we tested alpha, delta, epsilon and zeta. Dlx3 is primarily phosphorylated by PKC alpha. By deletion and mutational analysis, we show that the serine residue S(138), located in the homeodomain of Dlx3 protein, was specifically phosphorylated by PKC. The phosphorylation of purified Dlx3 proteins by PKC partially inhibited formation of complexes between Dlx3 protein and DNA. These results suggest that Dlx3 protein can be directly phosphorylated by PKC and this affects the DNA binding activity of Dlx3.

Sporadic inclusion body myositis correlates with increased expression and cross-linking by transglutaminases 1 and 2.

Sporadic inclusion body myositis (SIBM) is characterized by vacuolar degeneration of muscle fibers and intrafiber clusters of paired helical filaments with abnormal amyloid deposition. Because of their potential involvement in other degenerative disorders, we have examined the expression of transglutaminases (TGases) in normal and SIBM tissues. We report that at least two different enzymes, the ubiquitous TGase 2 as well as the TGase 1 enzyme, are present in muscle tissues. However, in comparison with normal tissue, the expression of TGases 1 and 2 was increased 2.5- and 4-fold in SIBM, accompanied by about a 20-fold higher total TGase activity. By immunohistochemical staining, in normal muscle, TGase 2 expression was restricted to some endomysial connective tissue elements, whereas TGase 1 and beta-amyloid proteins were not detectable. In SIBM muscle, both TGases 1 and 2 as well as amyloid proteins were brightly expressed and co-localized in the vacuolated muscle fibers, but none of these proteins colocalized with inflammatory cell markers. Next, we isolated high molecular weight insoluble proteins from SIBM muscle tissue and showed that they were cross-linked by about 6 residues/1000 residues of the isopeptide bond. Furthermore, by amino acid sequencing of solubilized tryptic peptides, they contain amyloid and skeletal muscle proteins. Together, these findings suggest that elevated expression of TGases 1 and 2 participate in the formation of insoluble amyloid deposits in SIBM tissue and in this way may contribute to progressive and debilitating muscle disease.

A case of type IIa early gastric cancer developed in pernicious anemia.

Pernicious anemia is an autoimmune disease characterized by a gastric mucosal defect which results in an insufficiency of intrinsic factor to facilitate the absorption of the physiologic amount of cobalamin. Increased risk of cancers of the stomach has been reported for patients with pernicious anemia. We report here a case of a 65 year old woman who had been diagnosed as having pernicious anemia 16 months previously, was receiving monthly vitamin B12 injections, and developed early gastric cancer type IIa by routine follow-up gastroscopic examination. This patient underwent endoscopic mucosal resection for an early gastric cancer lesion with a free resection margin.

Activating transcription factor 2 (ATF2) down-regulates hepatitis B virus X promoter activity by the competition for the activating protein 1 binding site and the formation of the ATF2-Jun heterodimer.

The hepatitis B viral X promoter is known to be positively autoregulated by its own HBx protein, which also interacts with many cellular regulatory proteins. We investigated the effect of activating transcription factor 2 (ATF2) on the activity of the X promoter. Cotransfection of the ATF2 expression vector with a X promoter-chloramphenicol acetyltransferase plasmid repressed the X promoter activity in HepG2 cells. HBx activated activating protein 1 (AP-1)-mediated transcription through the hepatitis B virus E element by 35-fold, while its activation activity was inhibited in the presence of ATF2, suggesting that ATF2 inhibited the autoactivation of X promoter by HBx and basal transcription mediated by AP-1. Since the binding sites of AP-1 and ATF2 in the hepatitis B virus E element overlap, the repression of X promoter activity by ATF2 is exerted by the competition for the AP-1 binding site and the formation of the ATF2-Jun heterodimer as in the case of the consensus AP-1 element. However, the small X promoter had a ATF2 binding site and was activated by ATF2. These results suggest that the syntheses of X proteins are differentially regulated by ATF2.

The retinoblastoma gene product activates transcription of the hepatitis B virus pregenomic promoter through the Sp1 binding sites.

The hepatitis B virus (HBV) pregenomic promoter is regulated by two enhancers and cis-elements. We have studied whether the retinoblastoma susceptibility gene product (Rb) modulates the activity of the HBV pregenomic promoter. Cotransfection of the Rb expression vector, phRB, with pCENCAT (containing the pregenomic promoter region: nt 248-1874) increased transcription from the HBV pregenomic promoter in HepG2 cells. Deletion analysis of the pregenomic promoter indicated that the region between nt -96 and -66, which contains two Sp1 binding sites, is responsible for activation by Rb. Mutation of the Sp1 binding sites abolished activation of the pregenomic promoter by Rb in the heterologous and natural promoter context. Therefore, our results suggest that Rb can activate the HBV pregenomic promoter through the Sp1 binding sites.

A positive regulatory sequence of hepatitis B viral small X promoter.

Hepatitis B viral X protein (HBx) and small X proteins (HBSx) are known to transactivate promoters for RNA polymerase II and RNA polymerase III. Small X promoter has been mapped in the 5'-distal half of the X open reading frame. A 5'-serial deletion analysis showed that there was a positive regulatory sequence for the efficient transcription of the small X promoter. Two cellular proteins of 110 kDa (p110) and 33 kDa (p33) bound at the 3' and 5' regions of the regulatory sequence, respectively. Mutation of p33-binding and p110-binding sites led to diminution and elevation, respectively, of activation properties of the positive element, suggesting that p33 participates in the transactivation and that p110 has an inhibitory effect on the function of p33. This possibility was further supported by the result demonstrating that in vitro phosphorylation of p110 reduced its target DNA-binding capability.

Upper gastrointestinal endoscopy in an urban hospital in northern Nigeria: association of presenting features with endoscopic findings.

In 326 fibreoptic upper gastrointestinal (GI) endoscopies performed in Evangel Hospital (Jos, Nigeria), pathology was found in 210 patients, and of a major nature such as peptic ulcer disease or cancer in 129 of these. The three most useful features to predict the presence of major pathology were epigastric tenderness (the single most useful feature), loss of weight and epigastric pain of a burning nature. These features were selected by stepwise discriminant analysis, which also led to the conclusion that the presence of at least two of these three features is an even more powerful predictor of major pathology.