Wheat Ym2 originated from Aegilops sharonensis and confers resistance to soil-borne Wheat yellow mosaic virus infection to the roots.

Wheat yellow mosaic virus (WYMV) is a pathogen transmitted into its host's roots by the soil-borne vector Polymyxa graminis. Ym1 and Ym2 genes protect the host from the significant yield losses caused by the virus, but the mechanistic basis of these resistance genes remains poorly understood. Here, it has been shown that Ym1 and Ym2 act within the root either by hindering the initial movement of WYMV from the vector into the root and/or by suppressing viral multiplication. A mechanical inoculation experiment on the leaf revealed that the presence of Ym1 reduced viral infection incidence, rather than viral titer, while that of Ym2 was ineffective in the leaf. To understand the basis of the root specificity of the Ym2 product, the gene was isolated from bread wheat using a positional cloning approach. The candidate gene encodes a CC-NBS-LRR protein and it correlated allelic variation with respect to its sequence with the host's disease response. Ym2 (B37500) and its paralog (B35800) are found in the near-relatives, respectively, Aegilops sharonensis and Aegilops speltoides (a close relative of the donor of bread wheat's B genome), while both sequences, in a concatenated state, are present in several accessions of the latter species. Structural diversity in Ym2 has been generated via translocation and recombination between the two genes and enhanced by the formation of a chimeric gene resulting from an intralocus recombination event. The analysis has revealed how the Ym2 region has evolved during the polyploidization events leading to the creation of cultivated wheat.

OsERdj7 is an ER-resident J-protein involved in ER quality control in rice endosperm.

OsERdj7 is one of six endoplasmic reticulum (ER)-resident J-domain-containing proteins (J-proteins) encoded by the rice genome that acts as a co-chaperone for Hsp70 and is characterized by the presence of two transmembrane domains. It is N-glycosylated and primarily exists in a dimeric form with a molecular mass of 64 kDa. When the microsomal fraction of maturing seeds was treated with alkaline, high salt or detergent compounds, OsERdj7 was solubilized, even in alkaline and high salt environments, indicating that it is not tightly integrated in the ER membrane. Next, to investigate its role during seed maturation, expression of OsERdj7 was specifically downregulated using RNA interference (RNAi) under the control of the endosperm-specific 16 kDa prolamin promoter in transgenic rice. As a result, the unfolded protein response (UPR) was induced in maturing seeds via activation of OsIRE1/OsbZIP50 and ATF6 orthologs, such as OsbZIP39 and OsbZIP60, leading to upregulation of several chaperones and folding enzymes. Furthermore, some prolamins (RM4 and RM9) were retained in the ER lumen in the form of a mesh-like structure without deposition to the inherent ER-derived protein bodies (PB-Is), although major storage protein glutelins were normally transported to protein storage vacuoles (PB-IIs). On the other hand, induction of ER associated degradation (ERAD) increased OsERdj7 expression in transgenic rice seeds in which ERAD related genes were highly expressed. Due to PDIL2-3 and OsHard3 co-immunoprecipitating with OsERdj7 in rice protoplasts, this result implicates OsERdj7 in the translocation of some seed proteins within the ER lumen and in the degradation of misfolded or unfolded proteins.

MYC-type transcription factors, MYC67 and MYC70, interact with ICE1 and negatively regulate cold tolerance in Arabidopsis.

The expression of hundreds of genes is induced by low temperatures via a cold signaling pathway. ICE1, a MYC-type transcription factor, plays an important role in the induction of CBF3/DREB1A to control cold-responsive genes and cold tolerance. To elucidate other molecular factors, a yeast 2-hybrid screening was performed. Two MYC-type transcription factors, MYC67 and MYC70, were identified as ICE1-interacting proteins. The myc mutants were more tolerant to freezing temperatures than wild type. CBF3/DREB1A and other cold-responsive genes were up-regulated in the myc mutants. Overexpression of the MYC genes increased the cold sensitivity and down-regulated the expression of cold-responsive genes. The MYC proteins interacted with the cis-elements in the CBF3/DREB1A promoter, probably to interfere interaction between ICE1 and the cis-elements. Taken together, these results demonstrate that MYC67 and MYC70, ICE1 interactors, negatively regulate cold-responsive genes and cold tolerance.

miR172 downregulates the translation of cleistogamy 1 in barley.

Background and Aims: Floret opening in barley is induced by the swelling of the lodicule, a trait under the control of the cleistogamy1 (cly1) gene. The product of cly1 is a member of the APETALA2 (AP2) transcription factor family, which inhibits lodicule development. A sequence polymorphism at the miR172 target site within cly1 has been associated with variation in lodicule development and hence with the cleistogamous phenotype. It was unclear whether miR172 actually functions in cly1 regulation and, if it does, which miR172 gene contributes to cleistogamy. It was also interesting to explore whether miR172-mediated cly1 regulation occurs at transcriptional level or at translational level. Methods: Deep sequencing of small RNA identified the miR172 sequences expressed in barley immature spikes. miR172 genes were confirmed by computational and expression analysis. miR172 and cly1 expression profiles were determined by in situ hybridization and quantitative expression analysis. Immunoblot analysis provided the CLY1 protein quantifications. Definitive evidence of the role of miR172 in cleistogamy was provided by a transposon Ds-induced mutant of Hv-miR172a. Key Results: A small RNA analysis of the immature barley spike revealed three isomers, miR172a, b and c, of which miR172a was the most abundant. In situ hybridization analysis showed that miR172 and cly1 co-localize in the lodicule primordium, suggesting that these two molecules potentially interact with one another. Immunoblot analysis showed that the sequence polymorphism at the miR172 target site within cly1 reduced the abundance of the CLY1 protein, but not that of its transcript. In a Ds-induced mutant of Hv-miR172a, which generates no mature miR172a, the lodicules fail to grow, resulting in a very small lodicule. Conclusions: Direct evidence is presented to show that miR172a acts to reduce the abundance of the CLY1 protein, which enables open flowering in barley.

Suppression of GPI-induced arthritis by oral administration of transgenic rice seeds expressing altered peptide ligands.

OBJECTIVE: To investigate the effects and mechanisms of transgenic rice seeds expressing the altered peptide ligand (APL) of human glucose-6-phosphate-isomerase (hGPI325-339) in mice model of GPI induced arthritis (GIA). METHODS: We generated transgenic rice expressing APL12 which was analog peptide of hGPI325-339. The transgenic rice seeds were orally administered prophylactically before the induction of GIA. The severity of arthritis and titers of serum anti-GPI antibodies were evaluated. We examined IL-17 production from splenocytes and inguinal lymph node (iLN) and mesenteric lymph nodes (mLN) cells and analyzed the expression levels of functional molecules from splenocytes and iLN cells. RESULTS: Prophylactic treatment of GIA mice with APL12 transgenic rice seeds (APL12-TG) significantly improved the severity of arthritis, histopathological arthritis scores, and decreased titers of serum anti-GPI antibodies, BAFF mRNA in iLN cells, IL-17 production in splenocytes and iLN cells compared with non-transgenic rice-treated mice. APL12-TG-treated GIA mice showed upregulation of Foxp3 and GITR protein in CD4+CD25+ cells in the spleen. CONCLUSION: APL12-TG improved the severity of GIA through a decrease in production of IL-17 and anti-GPI antibodies via upregulation of Foxp3 and GITR expression on regulatory T cells in spleen.

A GDSL-motif esterase/acyltransferase/lipase is responsible for leaf water retention in barley.

The hydrophobic cuticle covers the surface of the most aerial organs of land plants. The barley mutant eceriferum-zv (cer-zv), which is hypersensitive to drought, is unable to accumulate a sufficient quantity of cutin in its leaf cuticle. The mutated locus has been mapped to a 0.02 cM segment in the pericentromeric region of chromosome 4H. As a map-based cloning approach to isolate the gene was therefore considered unlikely to be feasible, a comparison was instead made between the transcriptomes of the mutant and the wild type. In conjunction with extant genomic information, on the basis of predicted functionality, only two genes were considered likely to encode a product associated with cutin formation. When eight independent cer-zv mutant alleles were resequenced with respect to the two candidate genes, it was confirmed that the gene underlying the mutation in each allele encodes a Gly-Asp-Ser-Leu (GDSL)-motif esterase/acyltransferase/lipase. The gene was transcribed in the epidermis, and its product was exclusively deposited in cell wall at the boundary of the cuticle in the leaf elongation zone, coinciding with the major site of cutin deposition. CER-ZV is speculated to function in the deposition of cutin polymer. Its homologs were found in green algae, moss, and euphyllophytes, indicating that it is highly conserved in plant kingdom.

Suppression of glucose-6-phosphate-isomerase induced arthritis by oral administration of transgenic rice seeds expressing altered peptide ligands of glucose-6-phosphate-isomerase.

OBJECTIVE: To investigate the effects of transgenic rice seeds expressing the altered peptide ligand (APL) of human glucose-6-phosphate-isomerase (hGPI325-339) in mice model of GPI-induced arthritis (GIA). METHODS: We generated transgenic rice expressing T-cell epitope of hGPI325-339 and APL12 contained in the seed endosperm. The transgenic rice seeds were orally administered prophylactically before the induction of GIA. The severity of arthritis and titers of serum anti-GPI antibodies were evaluated. We examined for IL-17 production in splenocytes and inguinal lymph node (iLN) cells, and analyzed the expression levels of functional molecules in splenocytes. RESULTS: Prophylactic treatment of GIA mice with APL12 transgenic (APL12-TG) rice seeds significantly reduced the severity of arthritis and titers of serum anti-GPI antibodies compared with non-transgenic (Non-TG) rice-treated mice. APL12-TG and hGPI325-339 transgenic (hGPI325-339-TG) rice seeds improved the histopathological arthritis scores and decreased IL-17 production compared with non-TG rice-treated mice. APL12-TG rice-treated GIA mice showed upregulation of Foxp3 and GITR protein in CD4 + CD25 + Foxp3+ cells in the spleen compared with non-TG rice- and hGPI325-339-TG rice-treated mice. CONCLUSION: APL12-TG rice seeds improved the severity of GIA through a decrease in production of IL-17 and anti-GPI antibodies via upregulation of Foxp3 and GITR expression on Treg cells in spleen.

OsHrd3 is necessary for maintaining the quality of endoplasmic reticulum-derived protein bodies in rice endosperm.

Large amounts of seed storage proteins (SSPs) are produced in the maturing endosperm of rice seeds. Rice SSPs are synthesized as secretory proteins on the rough endoplasmic reticulum (ER), and are transported and deposited into protein complexes called protein bodies (PB-I and PB-II). Due to the high production of SSPs, unfolded SSPs may be generated during this process. However, it was previously unclear how such unfolded proteins are selected among synthesized products and removed from the ER to maintain protein quality in the endosperm. Since Hrd3/SEL1L recognizes unfolded proteins in yeast and mammalian protein quality control systems, the role of OsHrd3 in protein quality control in rice endosperm was investigated. Co-immunoprecipitation experiments demonstrated that OsHrd3 interacts with components of the Hrd1 ubiquitin ligase complex such as OsOS-9 and OsHrd1 in rice protoplasts. Endosperm-specific suppression of OsHrd3 in transgenic rice reduced the levels of polyubiquitinated proteins and resulted in unfolded protein responses (UPRs) in the endosperm, suggesting that OsHrd3-mediated polyubiquitination plays an important role in ER quality control. It was found that a cysteine-rich 13kDa prolamin, RM1, was polyubiquitinated in wild-type (WT) seeds but not in OsHrd3 knockdown (KD) seeds. RM1 formed aberrant aggregates that were deposited abnormally in OsHrd3 KD seeds, resulting in deformed PB-I. Therefore, the quality of protein bodies is maintained by polyubiquitination of unfolded SSPs through the Hrd1 ubiquitin ligase system in rice endosperm.

Concentrated protein body product derived from rice endosperm as an oral tolerogen for allergen-specific immunotherapy--a new mucosal vaccine formulation against Japanese cedar pollen allergy.

The endoplasmic reticulum-derived type-I protein body (PB-I) from rice endosperm cells is an ideal candidate formulation for the oral delivery of bioencapsulated peptides as tolerogens for allergen-specific immunotherapy. In the present study, PBs containing the deconstructed Japanese cedar pollen allergens Cryptomeria japonica 1 (Cry j 1) and Cry j 2 were concentrated by treatment with thermostable α-amylase at 90°C to remove the starch from milled rice powder, which resulted in a 12.5-fold reduction of dry weight compared to the starting material. The modified Cry j 1 and Cry j 2 antigens in this concentrated PB product were more resistant to enzymatic digestion than those in the milled seed powder despite the absence of intact cell wall and starch, and remained stable for at least 10 months at room temperature without detectable loss or degradation. The high resistance of these allergens could be attributed to changes in protein physicochemical properties induced by the high temperature concentration process, as suggested by the decreased solubility of the antigens and seed proteins in PBs in step-wise-extraction experiments. Confocal microscopy showed that the morphology of antigen-containing PB-Is was preserved in the concentrated PB product. The concentrated PB product induced specific immune tolerance against Cry j 1 and Cry j 2 in mice when orally administered, supporting its potential use as a novel oral tolerogen formulation.

Emerging features of ER resident J-proteins in plants.

J-proteins are co-chaperone components of the HSP70 system. J-proteins stimulate Hsp70ATPase activity, which is responsible for stabilizing the interaction of Hsp70 with client proteins. J-proteins are localized in various intracellular compartments including the cytoplasm, mitochondria and endoplasmic reticulum (ER). Five types of ER resident J-proteins (ERdjs) have been found in plants (P58, ERdj2, ERdj2A, ERdj3B and ERdj7). Rice OsERdj3A is located in the vacuoleand protein storage vacuoles (PSV, PB-II) under conditions of ER stress. J-proteins that are localized to the vacuole or lysosome are not found in mammals and yeast, suggesting that the presence of OsERdj3A in the vacuole is plant-specific and one of the features unique to plant ERdjs. In this review, we summarize the current state of knowledge andrecent research advancements regarding plant ERdjs, and compare mammalian and yeast ERdjs with plant ERdjs.

Analysis of rice ER-resident J-proteins reveals diversity and functional differentiation of the ER-resident Hsp70 system in plants.

The heat shock protein 70 (Hsp70) chaperone system participates in protein folding and quality control of unfolded proteins. To examine the roles of co-chaperones in the rice Hsp70 chaperone system in the endoplasmic reticulum (ER), the functions of six ER-resident J-proteins (OsP58A, OsP58B, OsERdj2, OsERdj3A, OsERdj3B, and OsERdj7) in rice were investigated. The expression of OsP58B, OsERdj3A, and OsERdj3B was predominantly up-regulated in roots subjected to ER stress. This response was mediated by signalling through ATF6 orthologues such as OsbZIP39 and OsbZIP60, but not through the IRE1/OsbZIP50 pathway. A co-immunoprecipitation assay demonstrated that OsP58A, OsP58B, and OsERdj3B preferentially interact with the major OsBiP, OsBiP1, while OsERdj3A interacts preferentially with OsBiP5, suggesting that there are different affinities between OsBiPs and J-proteins. In the endosperm tissue, OsP58A, OsP58B, and OsERdj2 were mainly localized in the ER, whereas OsERdj2 was localized around the outer surfaces of ER-derived protein bodies (PB-Is). Furthermore, OsERdj3A was not expressed in wild-type seeds but was up-regulated in transgenic seeds accumulating human interleukin-7 (hIL-7). Since ERdj3A-green fluorescent protein (GFP) was also detected in vacuoles of callus cells under ER stress conditions, OsERdj3A is a bona fide vacuole-localized protein. OsP58A, OsP58B and OsERdj3A were differentially accumulated in transgenic plants expressing various recombinant proteins. These results reveal the functional diversity of the rice ER-resident Hsp70 system.

A regulatory cascade involving class II ETHYLENE RESPONSE FACTOR transcriptional repressors operates in the progression of leaf senescence.

Leaf senescence is the final process of leaf development that involves the mobilization of nutrients from old leaves to newly growing tissues. Despite the identification of several transcription factors involved in the regulation of this process, the mechanisms underlying the progression of leaf senescence are largely unknown. Herein, we describe the proteasome-mediated regulation of class II ETHYLENE RESPONSE FACTOR (ERF) transcriptional repressors and involvement of these factors in the progression of leaf senescence in Arabidopsis (Arabidopsis thaliana). Based on previous results showing that the tobacco (Nicotiana tabacum) ERF3 (NtERF3) specifically interacts with a ubiquitin-conjugating enzyme, we examined the stability of NtERF3 in vitro and confirmed its rapid degradation by plant protein extracts. Furthermore, NtERF3 accumulated in plants treated with a proteasome inhibitor. The Arabidopsis class II ERFs AtERF4 and AtERF8 were also regulated by the proteasome and increased with plant aging. Transgenic Arabidopsis plants with enhanced expression of NtERF3, AtERF4, or AtERF8 showed precocious leaf senescence. Our gene expression and chromatin immunoprecipitation analyses suggest that AtERF4 and AtERF8 targeted the EPITHIOSPECIFIER PROTEIN/EPITHIOSPECIFYING SENESCENCE REGULATOR gene and regulated the expression of many genes involved in the progression of leaf senescence. By contrast, an aterf4 aterf8 double mutant exhibited delayed leaf senescence. Our results provide insight into the important role of class II ERFs in the progression of leaf senescence.

ER stress response induced by the production of human IL-7 in rice endosperm cells.

Rice seed has been used as a production platform for high value recombinant proteins. When mature human interleukin 7 (hIL-7) was expressed as a secretory protein in rice endosperm by ligating the N terminal glutelin signal peptide and the C terminal KDEL endoplasmic reticulum (ER) retention signal to the hIL-7 cytokine to improve production yield, this protein accumulated at levels visible by Coomassie Brilliant Blue staining. However, the production of this protein led not only to a severe reduction of endogenous seed storage proteins but also to a deterioration in grain quality. The appearance of aberrant grain phenotypes (such as floury and shrunken) was attributed to ER stress induced by the retention of highly aggregated unfolded hIL-7 in the ER lumen, and the expression levels of chaperones such as BiPs and PDIs were enhanced in parallel with the increase in hIL-7 levels. The activation of this ER stress response was shown to be mainly mediated by the OsIRE1-OsbZIP50 signal cascade, based on the appearance of unconventional splicing of OsbZIP50 mRNA and the induction of OsBiP4&5. Interestingly, the ER stress response could be induced by lower concentrations of hIL-7 versus other types of cytokines such as IL-1b, IL-4, IL-10, and IL-18. Furthermore, several ubiquitin 26S proteasome-related genes implicated in ER-associated degradation were upregulated by hIL-7 production. These results suggest that severe detrimental effects on grain properties were caused by proteo-toxicity induced by unfolded hIL-7 aggregates in the ER, resulting in the triggering of ER stress.

Epstein-Barr virus-positive lymphoproliferative disorder associated with old organized chronic subdural hematoma.

This report describes a case of an immunocompetent 77-year-old male with Epstein-Barr virus (EBV)-positive lymphoproliferative disorder associated with calcified chronic subdural hematoma (CSH). On the day prior to consultation in our outpatient clinic, the patient fell from his bed, striking his frontal head on the floor. Magnetic resonance imaging showed ill-defined lesions in the right frontal-temporal subdural regions. At surgery, a hard and thickened outer membrane of a CSH and muddy organized subdural hematoma were observed. However, macroscopic neoplastic lesions were not apparent. Histologically, there were atypical lymphoid cells scattered or conglomerated in some areas of the thick outer membrane of the CSH. They were composed of occasional large atypical lymphoid cells. The lesions were accompanied by necrosis. Atypical lymphoid cells were immunopositive for B-cell markers but not for T-cell markers. EBNA2 was seen in the nuclei of tumor cells. Atypical lymphoid cells showed positive signals for EBV-encoded small RNAs (EBERs) on in situ hybridization. These findings were consistent with EBV-positive lymphoproliferative disorder associated with CSH. These results also suggested that EBV and the inflammatory reaction found in the CSH could be the etiological factors in the pathogenesis of lymphoproliferative disorder.

Increased tolerance to salt stress in the phosphate-accumulating Arabidopsis mutants siz1 and pho2.

High salinity is an environmental factor that inhibits plant growth and development, leading to large losses in crop yields. We report here that mutations in SIZ1 or PHO2, which cause more accumulation of phosphate compared with the wild type, enhance tolerance to salt stress. The siz1 and pho2 mutations reduce the uptake and accumulation of Na(+). These mutations are also able to suppress the Na(+) hypersensitivity of the sos3-1 mutant, and genetic analyses suggest that SIZ1 and SOS3 or PHO2 and SOS3 have an additive effect on the response to salt stress. Furthermore, the siz1 mutation cannot suppress the Li(+) hypersensitivity of the sos3-1 mutant. These results indicate that the phosphate-accumulating mutants siz1 and pho2 reduce the uptake and accumulation of Na(+), leading to enhanced salt tolerance, and that, genetically, SIZ1 and PHO2 are likely independent of SOS3-dependent salt signaling.

Cilostazol improves outcome after subarachnoid hemorrhage: a preliminary report.

BACKGROUND: Cerebral vasospasm (VS) is the most common cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage (SAH). Reversal of VS by intra-arterial infusion of cyclic adenosine monophosphate (cAMP)-elevating agents has been reported; however, the preventive role in the development of VS is not fully understood. This study is designed to evaluate the possible efficacy of using cilostazol, a selective inhibitor of phosphodiesterase type 3 and a cAMP-elevating agent, in patients with SAH. METHODS: In this prospective randomized study, we enrolled 100 SAH patients who met the following criteria: neck clipping within 72 h after onset, Hunt and Hess (HH) score ≤4, modified Rankin scale (mRS) score ≤2 prior to ictus, and no serious cardiovascular complications. Patients were divided into control and cilostazol groups; we focused on the effects of cilostazol on the decrease in the incidence of symptomatic VS, cerebral infarction, and the mRS score at discharge. RESULT: Patients' age, male/female ratio, mRS score prior to ictus, HH grade, Fisher group, site of the aneurysm, drugs prescribed during the observation period, and length of hospital stay were not different between the groups. Cilostazol did not significantly decrease the incidence of symptomatic VS (37.3% in the control vs. 22.4% in the cilostazol group, p = 0.183) and cerebral infarction (27.5% in control vs. 10.2% in the cilostazol, p = 0.091). However, mRS score was significantly improved at discharge (2.6 in controls vs. 1.5 in the cilostazol group, p = 0.041). Patients' age being ≤65 years (OR = 8.47, 95% CI = 2.45-29.32, p = 0.0007), Fisher group ≤3 (OR = 4.64, 95% CI = 1.00-21.45, p = 0.049), HH grade ≤2 (OR = 4.31, 95% CI = 1.27-14.59, p = 0.019), no hydrocephalus (OR = 8.55, 95% CI = 1.72-19.23, p = 0.0046), and cilostazol use (OR = 5.52, 95% CI = 1.61-18.90, p = 0.0065) were independent predictors of good outcomes (mRS score ≤2). CONCLUSION: Cilostazol may improve outcomes after SAH, but further double-blind, placebo-controlled studies are required for a definitive conclusion.

ICE1 Ser403 is necessary for protein stabilization and regulation of cold signaling and tolerance.

ICE1, a MYC-type transcription factor, has an important role in the induction of CBF3/DREB1A for regulation of cold signaling and tolerance. Here we reveal that serine 403 of ICE1 is involved in regulating the transactivation and stability of the ICE1 protein. Substitution of serine 403 by alanine enhanced the transactivational activity of ICE1 in Arabidopsis protoplasts. Over-expression of ICE1(S403A) conferred more freezing tolerance than ICE1(WT) in Arabidopsis, and the expression of cold-regulated genes such as CBF3/DREB1A, COR47 and KIN1 was enhanced in plants over-expressing ICE1(S403A). Furthermore, the ICE1(S403A) protein level was not changed after cold treatment, whereas the ICE1(WT) protein level was reduced. Interestingly, polyubiquitylation of the ICE1(S403A) protein in vivo was apparently blocked. These results demonstrate that serine 403 of ICE1 has roles in both transactivation and cold-induced degradation of ICE1 via the ubiquitin/26S proteasome pathway, suggesting that serine 403 is a key residue for the attenuation of cold-stress responses by HOS1-mediated degradation of ICE1.

Cold-responsive gene regulation during cold acclimation in plants.

Regulation of the transcriptome is necessary for plants to acquire cold tolerance, and cold induces several genes via a cold signaling pathway. The transcription factors CBF/DREB1 (C-repeat binding factor/dehydration responsive element binding1) and ICE1 (inducer of CBF expression1) have important roles in the regulation of cold-responsive gene expression. ICE1 is post-translationally regulated by ubiquitylation-mediated proteolysis and sumoylation. This mini-review highlights some recent studies on plant cold signaling. The relationships among cold signaling, salicylic acid accumulation and stomatal development are also discussed.

Novel acyl-CoA: cholesterol acyltransferase inhibitor: indoline-based sulfamide derivatives with low lipophilicity and protein binding ratio.

To find a novel acyl-CoA: cholesterol acyltransferase inhibitor, a series of sulfamide derivatives were synthesized and evaluated. Compound 1d, in which carboxymethyl moiety at the 5-position of Pactimibe was replaced by a sulfamoylamino group, showed 150-fold more potent anti-foam cell formation activity (IC(50): 0.02 microM), 1.6-fold higher log D(7.0) (4.63), and a slightly lower protein binding ratio (93.2%) than Pactimibe. Compound 1i, in which the octyl chain at the 1-position in 1d was replaced by an ethoxyethyl, showed markedly low log D(7.0) (1.73) and maintained 3-fold higher anti-foam cell formation activity (IC(50): 1.0 microM), than Pactimibe. The plasma protein binding ratio (PBR) of 1i was much lower than that of Pactimibe (62.5% vs. 98.1%), and its partition ratio to the rabbit atherosclerotic aorta after oral administration was higher than that of Pactimibe. Compound 1i at 10 microM markedly inhibited cholesterol esterification in atherosclerotic rabbit aortas even when incubated with serum, while Pactimibe had little effect probably due to its high PBR. In conclusion, compound 1i is expected to more efficiently inhibit the progression of atherosclerosis than Pactimibe.

Novel tetrahydroisoquinoline derivatives with inhibitory activities against acyl-CoA: cholesterol acyltransferase and lipid peroxidation.

To find a novel acyl-CoA: cholesterol acyltransferase (ACAT) inhibitor with anti-lipid peroxidative activity, a series of tetrahydroisoquinoline derivatives were synthesized and evaluated. A compound with a N-(4-hydroxy-2,3,5-trimethylphenyl)carbamoyl moiety at the 3-position and an octanoyl moiety at the 2-position (7) was demonstrated to show anti-foam cell formation activity stronger than and anti-lipid peroxidative activity comparable to those of Pactimibe, while it was hardly absorbed orally. To increase its bioavailability, the acyl chain at the 2-position was shortened and various polar or basic moieties were introduced at the 7-position of 7. Among the synthesized derivatives, (S)-7-dimethylamino-N-(4-hydroxy-2,3,5-trimethylphenyl)-2-isobutyryl-1,2,3,4-tetrahydroisoquinoline-3-carboxamide hydrochloride (21) showed about 16-fold stronger anti-foam cell formation activity, 3-fold stronger hepatic ACAT inhibitory activity, similar anti-low density lipoprotein (LDL) oxidative activity and 2-fold more potent protective activity against macrophage cell death by oxidative stress in comparison with Pactimibe. Compound 21 was efficiently absorbed after oral administration at 10 mg/kg in rats and dogs and its C(max) values were higher than its IC(50) values for in vitro activities. In conclusion, a tetrahydroisoquinoline structure is a useful scaffold for designing a phenolic anti-oxidative ACAT inhibitor, and compound 21 is expected to effectively prevent atherosclerosis.