Identification of autoantibodies against TRPM1 in patients with paraneoplastic retinopathy associated with ON bipolar cell dysfunction

Background

Paraneoplastic retinopathy (PR), including cancer-associated retinopathy (CAR) and melanoma-associated retinopathy (MAR), is a progressive retinal disease caused by antibodies generated against neoplasms not associated with the eye. While several autoantibodies against retinal antigens have been identified, there has been no known autoantibody reacting specifically against bipolar cell antigens in the sera of patients with PR. We previously reported that the transient receptor potential cation channel, subfamily M, member 1 (TRPM1) is specifically expressed in retinal ON bipolar cells and functions as a component of ON bipolar cell transduction channels. In addition, this and other groups have reported that human TRPM1 mutations are associated with the complete form of congenital stationary night blindness. The purpose of the current study is to investigate whether there are autoantibodies against TRPM1 in the sera of PR patients exhibiting ON bipolar cell dysfunction.

Methodology/Principal Findings

We performed Western blot analysis to identify an autoantibody against TRPM1 in the serum of a patient with lung CAR. The electroretinograms of this patient showed a severely reduced ON response with normal OFF response, indicating that the defect is in the signal transmission between photoreceptors and ON bipolar cells. We also investigated the sera of 26 patients with MAR for autoantibodies against TRPM1 because MAR patients are known to exhibit retinal ON bipolar cell dysfunction. Two of the patients were found to have autoantibodies against TRPM1 in their sera.

Conclusion/Significance

Our study reveals TRPM1 to be one of the autoantigens targeted by autoantibodies in at least some patients with CAR or MAR associated with retinal ON bipolar cell dysfunction.     

Effect of natural zeolite on methane production for anaerobic digestion of ammonium rich organic sludge

The effect of an inorganic additive on the methane production from NH(4+)-rich organic sludge during anaerobic digestion was investigated using different kinds of inorganic adsorbent zeolites (mordenite, clinoptilolite, zeolite 3A, zeolite 4A), clay mineral (vermiculite), and manganese oxides (hollandite, birnessite). The additions of inorganic materials resulted in significant NH4+ removals from the natural organic sludge ([NH4+]=1, 150 mg N/l), except for the H-type zeolite 3A and birnessite. However, an enhanced methane production was only achieved using natural mordenite. Natural mordenite also enhanced the methane production from the sludge with a markedly high NH4+ concentration (4500 mg N/l) during anaerobic digestion. Chemical analyses of the sludge after the digestion showed considerable increases in the Ca2+ and Mg2+ concentrations in the presence of natural mordenite, but not with synthetic zeolite 3A. The effect of Ca2+ or Mg2+ addition on the methane production was studied using Na(+)-exchanges mordenite and Ca2+ or Mg(2+)-enriched sludge. The simultaneous addition of Ca2+ ions and Na(+)-exchanged mordenite enhanced the methane production; the amount of produced methane was about three times greater than that using only the Na(+)-exchanged mordenite. In addition, comparing the methane production by the addition of natural mordenite or Ca2+ ions, the methane production with natural mordenite was about 1.7 times higher than that with only Ca2+ ions. The addition of 5% and 10% natural mordenite were suitable condition for obtaining a high methane production. These results indicated that the Ca2+ ions, which are released from natural mordenite by a Ca2+/NH4+ exchange, enhanced the methane production of the organic waste at a high NH4+ concentration. Natural mordenite has a synergistic effect on the Ca2+ supply as well on the NH4+ removal during anaerobic digestion, which is effective for the mitigation of NH4+ inhibition against methane production.     

Discovery of cyclic amine-substituted benzoic acids as PPARα agonists

A series of novel cyclic amine-substituted benzoic acid derivatives were synthesized and evaluated for their PPARα agonist activity. Strucure-activity relationship studies led to the identification of (S)-3-[3-[2-(4-chlorophenyl)-4-methylthyazole-5-carboxamido]piperidin-1-yl]benzoic acid (S)-4f (KRP-105) as a potent and high subtype-selective human PPARα agonist. (S)-4f showed excellent PK profile and oral administration of (S)-4f to high-fat diet dogs effectively lowered triglycerides.     

Cloning and High-Level Expression of α-Galactosidase cDNA from Penicillium purpurogenum

The cDNA coding for Penicillium purpurogenum α-galactosidase (αGal) was cloned and sequenced. The deduced amino acid sequence of the α-Gal cDNA showed that the mature enzyme consisted of 419 amino acid residues with a molecular mass of 46,334 Da. The derived amino acid sequence of the enzyme showed similarity to eukaryotic αGals from plants, animals, yeasts, and filamentous fungi. The highest similarity observed (57% identity) was to Trichoderma reesei AGLI. The cDNA was expressed in Saccharomyces cerevisiae under the control of the yeast GAL10 promoter. Almost all of the enzyme produced was secreted into the culture medium, and the expression level reached was approximately 0.2 g/liter. The recombinant enzyme purified to homogeneity was highly glycosylated, showed slightly higher specific activity, and exhibited properties almost identical to those of the native enzyme from P. purpurogenum in terms of the N-terminal amino acid sequence, thermoactivity, pH profile, and mode of action on galacto-oligosaccharides.α-Galactosidase (αGal) (EC 3.2.1.22) is of particular interest in view of its biotechnological applications. αGal from coffee beans demonstrates a relatively broad substrate specificity, cleaving a variety of terminal α-galactosyl residues, including blood group B antigens on the erythrocyte surface. Treatment of type B erythrocytes with coffee bean αGal results in specific removal of the terminal α-galactosyl residues, thus generating serological type O erythrocytes (8). Cyamopsis tetragonoloba (guar) αGal effectively liberates the α-galactosyl residue of galactomannan. Removal of a quantitative proportion of galactose moieties from guar gum by αGal improves the gelling properties of the polysaccharide and makes them comparable to those of locust bean gum (18). In the sugar beet industry, αGal has been used to increase the sucrose yield by eliminating raffinose, which prevents normal crystallization of beet sugar (28). Raffinose and stachyose in beans are known to cause flatulence. αGal has the potential to alleviate these symptoms, for instance, in the treatment of soybean milk (16).αGals are also known to occur widely in microorganisms, plants, and animals, and some of them have been purified and characterized (5). Dey et al. showed that αGals are classified into two groups based on their substrate specificity. One group is specific for low-M_r α-galactosides such as pNPGal (p-nitrophenyl-α-d-galactopyranoside), melibiose, and the raffinose family of oligosaccharides. The other group of αGals acts on galactomannans and also hydrolyzes low-M_r substrates to various extents (6).We have studied the substrate specificity of αGals by using galactomanno-oligosaccharides such as Gal³Man₃ (6³-mono-α-d-galactopyranosyl-β-1,4-mannotriose) and Gal³Man₄ (6³-mono-α-d-galactopyranosyl-β-1,4-mannotetraose). The structures of these galactomanno-oligosaccharides are shown in Fig. ​Fig.1.1. Mortierella vinacea αGal I (11) and yeast αGals (29) are specific for the Gal³Man₃ having an α-galactosyl residue (designated the terminal α-galactosyl residue) attached to the O-6 position of the nonreducing end mannose of β-1,4-mannotriose. On the other hand, Aspergillus niger 5-16 αGal (12) and Penicillium purpurogenum αGal (25) show a preference for the Gal³Man₄ having an α-galactosyl residue (designated the stubbed α-galactosyl residue) attached to the O-6 position of the third mannose from the reducing end of β-1,4-mannotetraose. The M. vinacea αGal II (26) acts on both substrates to almost equal extents. The difference in specificity may be ascribed to the tertiary structures of these enzymes. Open in a separate windowFIG. 1Structures of galactomanno-oligosaccharides.Genes encoding αGals have been cloned from various sources, including humans (3), plants (20, 32), yeasts (27), filamentous fungi (4, 17, 24, 26), and bacteria (1, 2, 15). αGals from eukaryotes show a considerable degree of similarity and are grouped into family 27 (10).Here we describe the cloning of P. purpurogenum αGal cDNA, its expression in Saccharomyces cerevisiae, and the purification and characterization of the recombinant enzyme.     

Agonists trigger G protein-mediated activation of the CPI-17 inhibitor phosphoprotein of myosin light chain phosphatase to enhance vascular smooth muscle contractility

Myosin light chain phosphatase (MLCP) plays a pivotal role in smooth muscle contraction by regulating Ca(2+) sensitivity of myosin light chain phosphorylation. A smooth muscle phosphoprotein called CPI-17 specifically and potently inhibits MLCP in vitro and in situ and is activated when phosphorylated at Thr-38, which increases its inhibitory potency 1000-fold. We produced a phosphospecific antibody for this site in CPI-17 and used it to study in situ phosphorylation of endogenous CPI-17 in arterial smooth muscle in response to agonist stimulation. In the intact femoral artery, CPI-17 phosphorylation was negligible at the resting state and was not increased during contraction induced by K(+) depolarization. The Ca(2+)-sensitizing agonists histamine and phenylephrine induced nearly equivalent contractions, but histamine generated significantly higher levels of CPI-17 phosphorylation. In alpha-toxin-permeabilized strips at pCa 6.7, contractile force and CPI-17 phosphorylation were proportional in response to histamine, guanosine 5'-O-(gamma-thiotriphosphate), and histamine plus guanyl-5'-yl thiophosphate, implying that histamine increased CPI-17 phosphorylation through activation of G proteins. Inhibitors of Rho-kinase (Y27632) and protein kinase C (PKC; GF109203X) reduced contraction and CPI-17 phosphorylation in parallel, suggesting that CPI-17 functions downstream of Rho kinases and PKC. The results show that agonists such as histamine signal through phosphorylation of CPI-17 to produce Ca(2+) sensitization of smooth muscle contraction.     

Rhombomere formation and hind-brain crest cell migration from prorhombomeric origins in mouse embryos

Prior to rhombomere development, structures called prorhombomeres appear in the mammalian hindbrain. This study clarifies the developmental relationship between prorhombomeres and their descendent rhombomeres and hindbrain crest cells in mouse embryos by focal dye injections at various levels of prorhombomere A (proRhA), proRhB, and proRhC, as well as at their boundaries. ProRhA gives rise to two rhombomeres, rhombomeres 1 and 2 (r1 and r2), as well as to crest cells that migrate into the first pharyngeal arch, including the trigeminal ganglion. ProRhB develops into r3 and r4 and produces crest cells populating the second arch and acousticofacial ganglion. The anterior portion of proRhC gives rise to r5 and r6 and to crest cells migrating into the third pharyngeal arch and the IXth ganglion; its posterior portion develops into r7 and releases crest cells into the fourth pharyngeal arch region as well as the Xth ganglion. These results suggest that the boundaries between prorhombomeres serve as lineage restrictions for both hind-brain neuroepithelial cells and for segmental origins of crest cell populations in mouse embryos. The Hox code of the mouse head can be schematized in a much simpler way based on this prorhombomeric organization of the hind-brain, suggesting that prorhombomeres primarily underlie mammalian hind-brain segmentation.     

Structure of the Bombyx mori fibroin light-chain-encoding gene: upstream sequence elements common to the light and heavy chain.

Two overlapping genomic clones containing the fibroin light-chain (Fib-L)-encoding gene (Fib-L) were obtained from the cosmid library of the silkworm, Bombyx mori J-139, by hybridization with the Fib-L cDNA clone. Sequencing of the 14.6-kb region revealed that Fib-L was 13472 bp long containing seven exons, and that the gene contained a large first intron which occupied about 60% of the gene. Comparison of restriction patterns of the J-139 Fib-L with those of eight other B. mori breeds producing normal-level fibroin demonstrated that considerable restriction-fragment length polymorphisms were present in regions containing the first intron and the 3′-flanking sequence. However, sizes of the Fib-L mRNA and the Fib-L polypeptide were very similar among the nine breeds tested, suggesting that the exon sequences and the splice signals were all well conserved. 5′-Flanking regions of Fib-L and the fibroin heavy-chain (Fib-H)-encoding gene (Fib-H) compared in this study contained three 18-30-bp sequences of high similarity and many 8-10-bp common elements, six of which coincided with the binding sites of homeodomain proteins. Gel retardation assays with the nuclear extracts of the posterior and middle silk glands suggested that protein factors present in the posterior silk-gland nuclei could bind to a set of those common upstream elements.     

A Waldenstr?m's macroglobulin with anti-G3m(b1) antibody activity.

A human monoclonal macroglobulin (IgM, K) from a patient (KI) with Waldenstr?m's macroglobulinemia was shown to have antibody activity against a human IgG (Gm) allotype. In hemagglutination tests, only one anti-D serum with G3m(b0b1) reacted with macroglobulin KI. Antiglobulin specificity of macroglobulin KI was determined to be an anti-G3m(b1) antibody by hemagglutination inhibition tests. Fab fragments from macroglobulin KI could react with human IgG3 protein possessing G3m(b1), but Fc fragments could not react. Gm phenotype in IgG isolated from serum KI was determined to be Gm(a,z,g,b0,s,t,u). This is the first report of a Waldenstr?m's macroglobulin with antiglobulin specificity against a Gm allotype.     

5'-Nucleotidase in rat liver lysosomes

5'-Nucleotidase was found in purified rat liver tritosomes. When tritosomes were subfractionated into the membrane and soluble contents fractions, 73% of the total 5'-nucleotidase activity was found in the membrane fraction and 24% in the soluble contents fraction. Immunoblotting using specific polyclonal antibodies against the rat liver plasma membrane 5'-nucleotidase showed that the mobilities on SDS-polyacrylamide gel electrophoresis of both 5'-nucleotidases in the membrane and contents fractions were identical to that of the enzyme in the plasma membranes (Mr = 72,000). 5'-Nucleotidases in the membrane and contents fractions were sensitive to neuraminidase and converted into a form that was 4 kDa smaller after digestion, as observed in the case of plasma membrane enzyme. 5'-Nucleotidases, both from the membrane and contents fractions, were purified using immunoaffinity chromatography, and the isoelectric points, heat stability, and oligomeric structure of the purified enzymes were compared. Isoelectric focusing and the heat stability test indicated the resemblance of the soluble enzyme to the membrane-bound enzyme. However, the membrane-bound enzyme aggregated in the absence of Triton X-100, whereas the soluble enzyme behaved as a dimer. The topography of 5'-nucleotidase in the tritosomal membranes was studied using antibodies against 5'-nucleotidase and neuraminidase treatment. The inhibition of 5'-nucleotidase were not observed in the intact tritosomal fraction until the tritosomes had been disrupted by osmotic shock. These results show that the active sites and the oligosaccharide chains of 5'-nucleotidase are located on the inside surface of the tritosomal membranes.