Mutant GGGGCC RNA prevents YY1 from binding to Fuzzy promoter which stimulates Wnt/β-catenin pathway in C9ALS/FTD

The GGGGCC hexanucleotide repeat expansion mutation in the chromosome 9 open reading frame 72 (C9orf72) gene is a major genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia (C9ALS/FTD). In this study, we demonstrate that the zinc finger (ZF) transcriptional regulator Yin Yang 1 (YY1) binds to the promoter region of the planar cell polarity gene Fuzzy to regulate its transcription. We show that YY1 interacts with GGGGCC repeat RNA via its ZF and that this interaction compromises the binding of YY1 to the FuzzyYY1 promoter sites, resulting in the downregulation of Fuzzy transcription. The decrease in Fuzzy protein expression in turn activates the canonical Wnt/β-catenin pathway and induces synaptic deficits in C9ALS/FTD neurons. Our findings demonstrate a C9orf72 GGGGCC RNA-initiated perturbation of YY1-Fuzzy transcriptional control that implicates aberrant Wnt/β-catenin signalling in C9ALS/FTD-associated neurodegeneration. This pathogenic cascade provides a potential new target for disease-modifying therapy.

[Efficacy and prognosis of infant kidney transplantation]

Objective: To analyze the effect and prognosis of infant kidney transplantation. Methods: Clinical data of 37 cases of infant kidney transplantation under 3 years old in Tongji Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology from June 1, 2017 to July 31, 2022 were retrospectively collected. These 37 cases included 31 primary kidney transplantation and 6 secondary kidney transplantation. Kaplan-Meier method was used to draw the survival curve of the transplanted kidney and the recipient, and the prognosis and complications were analyzed. Median follow-up was 18 months (range: 6-66 months). Results: The recipients were 20 males and 17 females, with a median age of 16 months (range: 2 months, 26 days to 36 months) and a median weight of 8 kg (range: 3.2 to 14.0 kg). The youngest child was only 2 months, 26 days old, and weighed only 3.2 kg. The most common primary disease of recipients was congenital nephrotic syndrome (13 cases, 41.9%). Intra-abdominal transplantation occurred in 19 cases (51.3%) and intra-iliac fossa transplantation occurred in the remaining 18 cases (48.6%). Postoperative renal function recovery was delayed in 7 cases (18.9%), and thrombosis caused renal function loss in 5 cases (13.5%), of which 4 cases received second renal transplantation and were successful. During the follow-up period, there were 11 cases of acute rejection (29.7%) and 6 cases of CMV pneumonia (16.2%). The estimated glomerular filtration rate 1 year after transplantation was higher than that 1 month after surgery [(101.9±22.1) vs (71.1±25.6) ml/(min·1.73m2), P<0.001], and remained constant 2 years after transplantation. Both the 1-year and 2-year survival rates of the transplanted kidney were 85.3%, and both the 1-year and 2-year survival rates of the recipients were 96.8%. Conclusion: Although the implementation of infant kidney transplantation is difficult, it can still achieve relatively satisfactory efficacy and prognosis.

A peptide inhibitor that rescues polyglutamine-induced synaptic defects and cell death through suppressing RNA and protein toxicities

Polyglutamine (polyQ) diseases, including spinocerebellar ataxias and Huntington's disease, are progressive neurodegenerative disorders caused by CAG triplet-repeat expansion in the coding regions of disease-associated genes. In this study, we found that neurotoxic small CAG (sCAG) RNA species, microscopic Ataxin-2 CAG RNA foci, and protein aggregates exist as independent entities in cells. Synaptic defects and neurite outgrowth abnormalities were observed in mutant Ataxin-2-expressing mouse primary cortical neurons. We examined the suppression effects of the CAG RNA-binding peptide beta-structured inhibitor for neurodegenerative diseases (BIND) in mutant Ataxin-2-expressing mouse primary cortical neurons and found that both impaired synaptic phenotypes and neurite outgrowth defects were rescued. We further demonstrated that BIND rescued cell death through inhibiting sCAG RNA production, Ataxin-2 CAG RNA foci formation, and mutant Ataxin-2 protein translation. Interestingly, when the expanded CAG repeats in the mutant Ataxin-2 transcript was interrupted with the alternative glutamine codon CAA, BIND's inhibitory effect on mutant protein aggregation was lost. We previously demonstrated that BIND interacts physically and directly with expanded CAG RNA sequences. Our data provide evidence that the BIND peptide associates with transcribed mutant CAG RNA to inhibit the formation of toxic species, including sCAG RNA, RNA foci, and polyQ protein translation and aggregation.

Lignin-carbohydrate complexes suppress SCA3 neurodegeneration via upregulating proteasomal activities

Lignin-carbohydrate complexes (LCCs) represent a group of macromolecules with diverse biological functions such as antioxidative properties. Polyglutamine (polyQ) diseases such as spinocerebellar ataxia type 3 (SCA3) comprise a set of neurodegenerative disorders characterized by the formation of polyQ protein aggregates in patient neurons. LCCs have been reported to prevent such protein aggregation. In this study, we identified a potential mechanism underlying the above anti-protein aggregation activity. We isolated and characterized multiple LCC fractions from bamboo and poplar and found that lignin-rich LCCs (BM-LCC-AcOH and PR-LCC-AcOH) effectively eliminated both monomeric and aggregated mutant ataxin-3 (ATXN3polyQ) proteins in neuronal cells and a Drosophila melanogaster SCA3 disease model. In addition, treatment with BM-LCC-AcOH or PR-LCC-AcOH rescued photoreceptor degeneration in vivo. At the mechanistic level, we demonstrated that BM-LCC-AcOH and PR-LCC-AcOH upregulated proteasomal activity. When proteasomal function was impaired, the ability of the LCCs to suppress ATXN3polyQ aggregation was abolished. Thus, we identified a previously undescribed proteasome-inducing function of LCCs and showed that such activity is indispensable for the beneficial effects of LCCs on SCA3 neurotoxicity.

[Relationship between obesity and death by multi-morbidity status in older adults in China]

Objective: To explore the relationship between obesity status and death stratified by different multi-morbidity status in older adults in China. Methods: Data for older Chinese adults aged ≥65 years were from Chinese Longitudinal Healthy Longevity Survey (CLHLS). Multi-morbidity patterns based on 13 chronic conditions were explored using exploratory factor analysis. Cox models were used to examine relationships between obesity status and death stratified by disease count and multi-morbidity patterns at baseline, respectively. Besides, obesity status was defined by baseline body mass index and waist circumference. Results: A total of 6 272 participants were included in the analyses. Multi-morbidity including cardio-metabolic, sensory perception and other patterns were identified. For those without any chronic condition, compared with those without central obesity, central obesity was associated with a higher risk for death (HR=1.66, 95%CI:1.04-2.66). For those only with one chronic condition, compared with normal weight, underweight was associated with a higher risk for death (HR=1.41, 95%CI: 1.10-1.80). For those with multi-morbidity, compared with normal weight, underweight increased the risk for death (HR=1.19, 95%CI:1.05-1.34). Compared with those without central obesity, central obesity decreased the risk for death (HR=0.88, 95%CI:0.78-0.99). Conclusions: Relationships between obesity status and death varied by multi-morbidity status in older adults in China. Underweight and non-central obesity were associated with increased risks for death in older adults with only one chronic disease or multi-morbidity. Therefore, it is necessary to pay attention to multi-morbidity status in the management of obesity in older adults and provide effective targeted body weight management plan.

[Mutational spectrum and its prognostic significance in childhood acute lymphoblastic leukemia based on next-generation sequencing technology]

Objective: This study analyzed the correlation between genetic mutation and prognostic significance in childhood acute lymphoblastic leukemia (ALL) . Methods: Targeted exome by next-generation sequencing (NGS) technology was used to carry out molecular profiling of untreated 141 children with ALL in Fujian Medical University Union Hospital from November 2016 to December 2019. Correlation of genetic features and clinical features and outcomes was analyzed. Results: Among the 141 pediatric patients with ALL, 160 somatic mutations were detected in 83 patients (58.9% ) , including 37 grade Ⅰ mutations and 123 grade Ⅱ mutations. Single nucleotide variation was the most common type of mutation. KRAS was the most common mutant gene (12.5% ) , followed by NOTCH1 (11.9% ) , and NRAS (10.6% ) . RAS pathway (KRAS, FLT3, PTPN11) , PAX5 and TP53 mutations were only detected, and NRAS mutations was mainly found in B-ALL while FBXW7 and PTEN mutations were only found, and NOTCH1 mutation was mainly detected in T-ALL. The average number of mutations detected in each child with T-ALL was significantly higher than in children with B-ALL (4.16±1.33 vs 2.04±0.92, P=0.004) . The children were divided into mutation and non-mutation groups according to the presence or absence of genetic variation. There were no statistically significant differences in sex, age, newly diagnosed white blood cell count, minimal or measurable residual disease monitoring results, expected 3-year event-free survival (EFS) and overall survival (OS) between the two groups (P>0.05) . On the other hand, the proportion of T-ALL and fusion gene negative children in the mutant group was significantly higher than the non-mutation group (P=0.021 and 0.000, respectively) . Among the patients without fusion gene, the EFS of children with grade I mutation was significantly lower than children without grade I mutation (85.5% vs 100.0% , P=0.039) . Among children with B-ALL, the EFS of those with TP53 mutation was significantly lower than those without TP53 mutation (37.5% vs 91.2% , P<0.001) . Conclusion: Genetic variation is more common in childhood ALL and has a certain correlation with clinical phenotype and prognosis. Therefore, targeted exome by NGS can be used as an important supplement to the traditional morphology, immunology, cytogenetics, and molecular biology classification.

Insight in the Recent Application of Polyphenols From Biomass

Biomass polyphenols are bio-active macromolecules with distinct chemical structures in a variety of biomass. In recent years, the study of biomass polyphenols and their application in food and medicine fields has become a research hotspot, which predominantly focuses on the preparation, purification, structural identifications, and measurements of biological activities. Many studies describe methodologies for extraction and application of polyphenols, but comprehensive work to review its physiological activities like drugs and health products are lacking. This paper comprehensively unlocks the bioactivities of antioxidant, antibacterial, antitumor, anticancer, neuroprotection, control of blood sugar, regulation of blood fat, and promotion of gastrointestinal health functions of polyphenols from different biomass sources. This review will serve as an illuminating resource for the global scientific community, especially for those who are actively working to promote the advances of the polyphenols research field.

CAG RNAs induce DNA damage and apoptosis by silencing NUDT16 expression in polyglutamine degeneration

DNA damage plays a central role in the cellular pathogenesis of polyglutamine (polyQ) diseases, including Huntington's disease (HD). In this study, we showed that the expression of untranslatable expanded CAG RNA per se induced the cellular DNA damage response pathway. By means of RNA sequencing (RNA-seq), we found that expression of the Nudix hydrolase 16 (NUDT16) gene was down-regulated in mutant CAG RNA-expressing cells. The loss of NUDT16 function results in a misincorporation of damaging nucleotides into DNAs and leads to DNA damage. We showed that small CAG (sCAG) RNAs, species generated from expanded CAG transcripts, hybridize with CUG-containing NUDT16 mRNA and form a CAG-CUG RNA heteroduplex, resulting in gene silencing of NUDT16 and leading to the DNA damage and cellular apoptosis. These results were further validated using expanded CAG RNA-expressing mouse primary neurons and in vivo R6/2 HD transgenic mice. Moreover, we identified a bisamidinium compound, DB213, that interacts specifically with the major groove of the CAG RNA homoduplex and disfavors the CAG-CUG heteroduplex formation. This action subsequently mitigated RNA-induced silencing complex (RISC)-dependent NUDT16 silencing in both in vitro cell and in vivo mouse disease models. After DB213 treatment, DNA damage, apoptosis, and locomotor defects were rescued in HD mice. This work establishes NUDT16 deficiency by CAG repeat RNAs as a pathogenic mechanism of polyQ diseases and as a potential therapeutic direction for HD and other polyQ diseases.

[Clinical features and prognosis of ETV6-RUNX1-positive childhood B-precursor acute lymphocyte leukemia]

目的

探讨ETV6-RUNX1融合基因阳性儿童急性前体B淋巴细胞白血病（B-ALL）的临床特征及预后。

方法

回顾性分析2011年4月至2020年5月福建医科大学附属协和医院小儿血液科收治的927例初诊B-ALL患儿的临床资料。根据ETV6-RUNX1检测结果，分为ETV6-RUNX1⁺组及ETV6-RUNX1⁻组，对比两组的临床特征及预后；182例ETV6-RUNX1⁺患儿规范治疗，其中144例接受中国儿童白血病协作组（CCLG）-ALL 2008方案治疗（CCLG-ALL 2008方案组），38例接受中国儿童癌症协作组（CCCG）-ALL 2015方案治疗（CCCG-ALL 2015方案组），对比两种方案的疗效、严重不良反应（SAE）发生率及治疗相关死亡（TRM）率。

结果

927例B-ALL患儿中，189例（20.4%）ETV6-RUNX1阳性。ETV6-RUNX1⁺组初诊时有危险因素（年龄≥10岁或<1岁，WBC≥50×10⁹/L）的患者比例均显著低于ETV6-RUNX1⁻组（P值分别为0.000和0.001），而泼尼松诱导试验反应良好、诱导化疗第15天或第19天微小残留病（MRD）<1%，以及诱导化疗第33天或第46天MRD<0.01%的患者比例显著高于ETV6-RUNX1⁻组（P值分别为0.001、0.028和0.004）。ETV6-RUNX1⁺组的5年无事件生存（EFS）及总生存（OS）率均显著高于ETV6-RUNX1⁻组（EFS：89.8%对83.2%，P＝0.003；OS：90.2%对86.3%，P＝0.030）。CCLG-ALL 2008组感染相关SAE发生率显著高于CCCG-ALL 2015组（27.1%对5.3%，P＝0.004），TRM发生率也高于CCCG-ALL 2015组，但差异无统计学意义（4.9%对0，P＝0.348）。

结论

ETV6-RUNX1⁺儿童B-ALL初诊危险因素较少，早期治疗反应较好，复发率低，总体预后良好；适当减低化疗强度，可降低感染相关SAE及TRM发生率，并进一步提高该亚型ALL患儿的OS率。

Pan-cancer investigation reveals mechanistic insights of planar cell polarity gene Fuz in carcinogenesis

The fuzzy planar cell polarity protein (Fuz) is an effector component of the planar cell polarity (PCP) signaling. Together with other core and effector proteins, the PCP pathway controls polarized cell movements. Fuz was also reported as a negative regulator of cell survival. In this study, we performed a pan-cancer survey to demonstrate the role of Fuz in multiple types of cancer. In head-neck squamous cell carcinoma and lung adenocarcinoma tumor samples, a reduction of Fuz transcript expression was detected. This coincides with the poor overall survival probabilities of these patients. We further showed that Fuz promoter hypermethylation contributes to its transcriptional downregulation. Meanwhile, we also identified a relatively higher mutation frequency at the 404^th arginine amino acid residue in the coding sequence of Fuz locus, and further demonstrated that mutant Fuz proteins perturb the pro-apoptotic function of Fuz. In summary, our study unveiled an intriguing relationship between Fuz dysregulation and cancer prognosis, and further provides mechanistic insights of Fuz's involvement in carcinogenesis.

A heterozygous mutation in the CCDC88C gene likely causes early-onset pure hereditary spastic paraplegia: a case report

BACKGROUND

CCDC88C is a ubiquitously expressed protein with multiple functions, including roles in cell polarity and the development of dendrites in the nervous system. Bi-allelic mutations in the CCDC88C gene cause autosomal recessive congenital hydrocephalus (OMIM #236600). Studies recently linked heterozygous mutations in CCDC88C to the development of the late-onset spinocerebellar ataxia type 40 (OMIM #616053).

CASE PRESENTATION

A 48-year-old Sudanese female presented with pure early onset hereditary spastic paraplegia. Exome sequencing, in-silico analysis, and Sanger sequencing identified the heterozygous NM_001080414.4:c.1993G > A (p.E665K) variant in CCDC88C as a potential cause of her illness. To explore the pathogenicity of the NM_001080414.4:c.1993G > A (p.E665K) variant, we expressed it in human embryonic kidney 293 cells and assessed its effects on apoptosis. In our experiment, NM_001080414.4:c.1993G > A (p.E665K) induced JNK hyper-phosphorylation and enhanced apoptosis. In contrast to previous reports, our patient developed neurological symptoms in early childhood and showed neither features of cerebellar ataxia, extrapyramidal signs, nor evidence of intellectual involvement.

CONCLUSION

We, herein, heighlighted the possibility of extending the phenotype associated with variants in CCDC88C to include early-onset pure hereditary spastic paraplegia.

Isolation and Identification of a Novel Anti-protein Aggregation Activity of Lignin-Carbohydrate Complex From Chionanthus retusus Leaves

Lignin-carbohydrate complex (LCC) is the biological macromolecule that has been demonstrated to exert multiple biological functions, including antioxidant, anti-inflammation and anti-tumorigenesis, which support its broad application in the bioengineering field. However, it remains elusive the involvements of LCC in human neurological disorders, especially those with the overproduction of reactive oxygen species (ROS), such as spinocerebellar ataxias (SCAs). In this study, we found a previously undetermined anti-protein aggregation activity of LCC. Initially, two individual LCC preparations and carbohydrate-free lignin were isolated from the water-extracted waste residues of Chionanthus retusus (C. retusus) tender leaves. The chemical compositional analysis revealed that lignin (61.5%) is the predominant constituent in the lignin-rich LCC (LCC-L-CR), whereas the carbohydrate-rich LCC (LCC-C-CR) is mainly composed of carbohydrate (60.9%) with the xylan as the major constituent (42.1%). The NMR structural characterization showed that LCC-L-CR preparation is enriched in benzyl ether linkage, while phenyl glycoside is the predominant type of linkage in LCC-C-CR. Both LCC and lignin preparations showed antioxidant activities as exemplified by their abilities to scavenge free radicals in cultured mammalian cells and ROS in zebrafish. We further demonstrated a pronounced capability of LCC-L-CR in inhibiting the aggregation of expanded Ataxin-3, disease protein of SCA type 3, in human neuronal cells. Taken together, our study highlights the antioxidant and novel anti-protein aggregation activities of the C. retusus tender leaves-derived LCC.

[Strategy and clinical outcome of deceased donor kidney transplantation for presensitized recipients]

Objective: To explore the management strategy and clinical outcome of renal transplantation in presensitized recipients using deceased donor kidneys. Methods: From January 2011 to June 2018, twenty-one presensitized patients, including 8 with positive donor specific antibodies (DSA) and 13 with positive panel-reactive antibodies (PRA) but no DSA, received renal retransplantation from deceased donors in our center. The incidence of delayed graft function (DGF) and acute rejection (AR), changes of DSA, and the graft and patient survival were retrospectively analyzed. Results: None of the renal allografts had primary non-function (PNF) and DGF after transplantation. Four of the 13 recipients with PRA(+)/DSA-had a total of 5 episodes of acute cell-mediated rejection (CMR), while 5 of 8 recipients with pre-existing DSA(+) developed AR, including 3 cases with CMR alone and 2 cases with mixed AR. All episodes of rejection were successfully reversed after targeted treatment. Interestingly, of the 8 recipients with positive preformed DSA, 4 cases with positive DR-DSA and/or class Ⅰ-DSA had their DSA disappeared after transplantation, whereas DQ-DSA remained positive in 4 of 5 recipients. After a median follow-up of 26 months, all recipients maintained normal renal allograft function, and the survival rates of both graft and recipient were 100%. Conclusions: With the use of deceased donors, kidney transplantation can be successfully performed in presensitized patients by appropriate HLA-matching screening, choosing donor kidneys with good quality, and the combination of optimal perioperative treatment.

FipoQ/FBXO33, a Cullin-1-based ubiquitin ligase complex component modulates ubiquitination and solubility of polyglutamine disease protein

Polyglutamine (polyQ) diseases describe a group of progressive neurodegenerative disorders caused by the CAG triplet repeat expansion in the coding region of the disease genes. To date, nine such diseases, including spinocerebellar ataxia type 3 (SCA3), have been reported. The formation of SDS-insoluble protein aggregates in neurons causes cellular dysfunctions, such as impairment of the ubiquitin-proteasome system, and contributes to polyQ pathologies. Recently, the E3 ubiquitin ligases, which govern substrate specificity of the ubiquitin-proteasome system, have been implicated in polyQ pathogenesis. The Cullin (Cul) proteins are major components of Cullin-RING ubiquitin ligases (CRLs) complexes that are evolutionarily conserved in the Drosophila genome. In this study, we examined the effect of individual Culs on SCA3 pathogenesis and found that the knockdown of Cul1 expression enhances SCA3-induced neurodegeneration and reduces the solubility of expanded SCA3-polyQ proteins. The F-box proteins are substrate receptors of Cul1-based CRL. We further performed a genetic modifier screen of the 19 Drosophila F-box genes and identified F-box involved in polyQ pathogenesis (FipoQ) as a genetic modifier of SCA3 degeneration that modulates the ubiquitination and solubility of expanded SCA3-polyQ proteins. In the human SK-N-MC cell model, we identified that F-box only protein 33 (FBXO33) exerts similar functions as FipoQ in modulating the ubiquitination and solubility of expanded SCA3-polyQ proteins. Taken together, our study demonstrates that Cul1-based CRL and its associated F-box protein, FipoQ/FBXO33, modify SCA3 protein toxicity. These findings will lead to a better understanding of the disease mechanism of SCA3 and provide insights for developing treatments against SCA3. Cover Image for this issue: doi: 10.1111/jnc.14510.

A Peptidylic Inhibitor for Neutralizing r(GGGGCC)exp-Associated Neurodegeneration in C9ALS-FTD

One drug, two diseases is a rare and economical therapeutic strategy that is highly desirable in the pharmaceutical industry. We previously reported a 21-amino acid peptide named beta-structured inhibitor for neurodegenerative diseases (BIND) that can effectively inhibit expanded CAG trinucleotide toxicity in polyglutamine (polyQ) diseases. Here we report that BIND also effectively inhibits GGGGCC repeat-mediated neurodegeneration in vitro and in vivo. When fused with a cell-penetrating peptide derived from the transactivator of transcription (TAT) protein of the HIV, TAT-BIND reduces cell death, formation of GGGGCC RNA foci, and levels of poly-GR, poly-GA, and poly-GP dipeptide proteins in cell models of C9ORF72-associated amyotrophic lateral sclerosis and frontotemporal dementia (C9ALS-FTD). We showed that TAT-BIND disrupts the interaction between GGGGCC RNA and nucleolin protein, restores rRNA maturation, and inhibits mislocalization of nucleolin and B23, which eventually suppresses nucleolar stress in C9ALS-FTD. In a Drosophila model of C9ALS-FTD, TAT-BIND suppresses retinal degeneration, rescues climbing ability, and extends the lifespan of flies. In contrast, TAT-BIND has no effect on UAS-poly-glycine-arginine (poly-GR)₁₀₀-expressing flies, which generate only poly-GR protein toxicity, indicating BIND ameliorates toxicity in C9ALS-FTD models via a _r(GGGGCC)_exp-dependent inhibitory mechanism. Our findings demonstrated that, apart from being a potential therapeutic for polyQ diseases, BIND is also a potent peptidylic inhibitor that suppresses expanded GGGGCC RNA-mediated neurodegeneration, highlighting its potential application in C9ALS-FTD treatment.

Transcriptional dysregulation in neurodegenerative diseases: Who tipped the balance of Yin Yang 1 in the brain?

Yin Yang 1 (YY1) is a multi-functional transcription factor that regulates gene expression in a range of cell types, including neurons. It controls neuronal differentiation, as well as neuronal specification and migration during the development of the mammalian nervous system. Besides, YY1 also mediates the transcription of genes that are required for neuronal survival. An impairment of the transcriptional function of YY1 causes neuronal death. This review summarizes recent research findings that unveil the dysfunction of YY1 in multiple neurodegenerative disorders. The expression of disease proteins perturbs the function of YY1 via distinct molecular mechanisms, including recruitment to protein aggregates, protein degradation and aberrant nuclear/cytoplasmic shuttling. Understanding the pathogenic roles of YY1 will further broaden our knowledge of the disease mechanisms in distinct neurodegenerative disorders.

AQAMAN, a bisamidine-based inhibitor of toxic protein inclusions in neurons, ameliorates cytotoxicity in polyglutamine disease models

Polyglutamine (polyQ) diseases are a group of dominantly inherited neurodegenerative disorders caused by the expansion of an unstable CAG repeat in the coding region of the affected genes. Hallmarks of polyQ diseases include the accumulation of misfolded protein aggregates, leading to neuronal degeneration and cell death. PolyQ diseases are currently incurable, highlighting the urgent need for approaches that inhibit the formation of disaggregate cytotoxic polyQ protein inclusions. Here, we screened for bisamidine-based inhibitors that can inhibit neuronal polyQ protein inclusions. We demonstrated that one inhibitor, AQAMAN, prevents polyQ protein aggregation and promotes de-aggregation of self-assembled polyQ proteins in several models of polyQ diseases. Using immunocytochemistry, we found that AQAMAN significantly reduces polyQ protein aggregation and specifically suppresses polyQ protein-induced cell death. Using a recombinant and purified polyQ protein (thioredoxin-Huntingtin-Q46), we further demonstrated that AQAMAN interferes with polyQ self-assembly, preventing polyQ aggregation, and dissociates preformed polyQ aggregates in a cell-free system. Remarkably, AQAMAN feeding of Drosophila expressing expanded polyQ disease protein suppresses polyQ-induced neurodegeneration in vivo In addition, using inhibitors and activators of the autophagy pathway, we demonstrated that AQAMAN's cytoprotective effect against polyQ toxicity is autophagy-dependent. In summary, we have identified AQAMAN as a potential therapeutic for combating polyQ protein toxicity in polyQ diseases. Our findings further highlight the importance of the autophagy pathway in clearing harmful polyQ proteins.

Planar cell polarity gene Fuz triggers apoptosis in neurodegenerative disease models

Planar cell polarity (PCP) describes a cell-cell communication process through which individual cells coordinate and align within the plane of a tissue. In this study, we show that overexpression of Fuz, a PCP gene, triggers neuronal apoptosis via the dishevelled/Rac1 GTPase/MEKK1/JNK/caspase signalling axis. Consistent with this finding, endogenous Fuz expression is upregulated in models of polyglutamine (polyQ) diseases and in fibroblasts from spinocerebellar ataxia type 3 (SCA3) patients. The disruption of this upregulation mitigates polyQ-induced neurodegeneration in Drosophila We show that the transcriptional regulator Yin Yang 1 (YY1) associates with the Fuz promoter. Overexpression of YY1 promotes the hypermethylation of Fuz promoter, causing transcriptional repression of Fuz Remarkably, YY1 protein is recruited to ATXN3-Q84 aggregates, which reduces the level of functional, soluble YY1, resulting in Fuz transcriptional derepression and induction of neuronal apoptosis. Furthermore, Fuz transcript level is elevated in amyloid beta-peptide, Tau and α-synuclein models, implicating its potential involvement in other neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. Taken together, this study unveils a generic Fuz-mediated apoptotic cell death pathway in neurodegenerative disorders.

A peptidylic inhibitor for neutralizing expanded CAG RNA-induced nucleolar stress in polyglutamine diseases

Polyglutamine (polyQ) diseases are a class of progressive neurodegenerative disorders characterized by the expression of both expanded CAG RNA and misfolded polyQ protein. We previously reported that the direct interaction between expanded CAG RNA and nucleolar protein nucleolin (NCL) impedes preribosomal RNA (pre-rRNA) transcription, and eventually triggers nucleolar stress-induced apoptosis in polyQ diseases. Here, we report that a 21-amino acid peptide, named "beta-structured inhibitor for neurodegenerative diseases" (BIND), effectively suppresses toxicity induced by expanded CAG RNA. When administered to a cell model, BIND potently inhibited cell death induced by expanded CAG RNA with an IC50 value of ∼0.7 µM. We showed that the function of BIND is dependent on Glu2, Lys13, Gly14, Ile18, Glu19, and Phe20. BIND treatment restored the subcellular localization of nucleolar marker protein and the expression level of pre-45s rRNA Through isothermal titration calorimetry analysis, we demonstrated that BIND suppresses nucleolar stress via a direct interaction with CAG RNA in a length-dependent manner. The mean binding constants (KD) of BIND to SCA2CAG22 , SCA2CAG42 , SCA2CAG55 , and SCA2CAG72 RNA are 17.28, 5.60, 4.83, and 0.66 µM, respectively. In vivo, BIND ameliorates retinal degeneration and climbing defects, and extends the lifespan of Drosophila expressing expanded CAG RNA. These effects suggested that BIND can suppress neurodegeneration in diverse polyQ disease models in vivo and in vitro without exerting observable cytotoxic effect. Our results collectively demonstrated that BIND is an effective inhibitor of expanded CAG RNA-induced toxicity in polyQ diseases.

TC > 0.05 as a Pharmacokinetic Parameter of Paclitaxel for Therapeutic Efficacy and Toxicity in Cancer Patients

BACKGROUND

Paclitaxel (PTX) has remarkable anti-tumor activity, but it causes severe toxicities. There is an urgent need to seek an appropriate pharmacokinetic parameter of PTX to improve treatment efficacy and reduce adverse effects.

OBJECTIVE

To evaluate the association of pharmacokinetic parameter TC > 0.05 of paclitaxel (PTX) and its therapeutic efficacy and toxicity in patients with solid tumors.

METHODS

A total of 295 patients with ovarian cancer, esophageal cancer, breast cancer, and non-small cell lung cancer (NSCLC), who were admitted to the Tumor Hospital of Shantou University Medical College, China, were recruited for this study. Patients received 3 weeks of PTX chemotherapy. The plasma concentrations of PTX were examined using the MyPaclitaxel™ kit. The patients' PTX TC > 0.05 (the time during which PTX plasma concentration exceed 0.05µmol/L) were calculated based on pharmacokinetic analysis.

RESULTS

The results showed that: (1) the concentrations of PTX in these 295 patients ranged from 0.0358-0.127 µmol/L; (2) the PTX TC > 0.05 ranged from 14 to 38h with a median time of 27h; (3) among all treatment cycles, there was a statistically significant difference in the PTX TC > 0.05 between CR+PR and SD+PD; (4) with the increasing value of TC > 0.05, level of leukopenia and leukopenic fever increased; (5) high PTX TC > 0.05 led to the occurrence of neutropenia, neutropenic fever, severe anemia, and severe peripheral neurotoxicity. Taken together, our results indicated that the pharmacokinetic parameter PTX TC > 0.05 was an effective measure of treatment efficacy and toxicity in patients with solid tumors. Maintaining PTX TC > 0.05 at 26 to 30h could improve its efficacy and reduce the incidence of leukopenia, neutropenia, anemia, and peripheral neurotoxicity in these patients.

CONCLUSION

PTX TC > 0.05 is a key pharmacokinetic parameter of PTX which should be monitored to optimize individual treatment in patients with solid tumors.

[Risk factors for acute rejection in living-donor kidney transplant recipients in China: a subgroup analysis of a multi-center, registry study]

Objective: To evaluate pre-and early post-transplantation risk factors for acute rejection(AR) in kidney recipients. Methods: This subgroup analysis of a multi-center registry study was conducted on living-donor kidney transplant recipients in China with 10 years of follow-up. This study analyzed 1 255 recipients including 921 males(73.4%) and with a mean age of (33±10)years. Data from patients were first analyzed with univariate analysis and then multivariate analysis was used for finding out the potential risk factors of AR. Results: A total of 106(8.4%) patients were suspected with AR after kidney transplantation, while 1 149 patients were considered as non-AR. Multivariable analysis demonstrated a significant influence of recipient age and cold ischemia time(CIT) on the occurrence of AR(OR: 0.956, 95% CI: 0.923-0.990; OR: 1.006, 95% CI: 1.002-1.011, respectively). The frequency of severe infection was significantly higher in the AR group than non-AR group(38.7% vs 10.8%; P<0.000 1). The occurrence of new-onset diabetes mellitus and tumors was similar in the two groups. Conclusions: Recipient age and CIT are risk factors for AR after living-donor kidney transplantation. Reducing CIT and intensive management of younger recipient could benefit kidney transplant patients.

Optic atrophy differentially diagnosed as spinocerebellar ataxia from Leber hereditary optic neuropathy by gene mutation analysis

Optic atrophy describes a group of diseases of retinal ganglion cells and axons that eventually lead to loss of vision. Optic atrophy has both congenital and acquired causes, and its diagnosis (or differential diagnosis) is complicated. This case report describes a 20-year-old man who presented with a 1-year history of progressive vision loss in both eyes and no obvious systemic symptoms. Fundus examination revealed bilateral optic atrophy. Based on clinical characteristics, visual field analysis and pattern visual evoked potential examination, the presumptive diagnosis was Leber hereditary optic neuropathy (LHON). Analysis of mitochondrial DNA indicated the absence of all of three common mutations associated with LHON (m.3460G>A, m.11778G>A, m.14484T>C). Detailed questioning of the patient revealed a history of prolonged language development and poor balance. Neurological examination indicated abnormal co-ordination, suggesting the presence of inherited spinocerebellar ataxia (SCA). Analysis of the SCA7 gene revealed a high number of trinucleotide repeats [(CAG)(n), n > 64], confirming the diagnosis of SCA. The aetiology of optic atrophies is complicated and the molecular genetic detection approach provides the best information for diagnosing these diseases.

A novel lift-off method for fabricating patterned and vertically-aligned W18O49 nanowire arrays with good field emission performance

A novel lift-off method has been developed for fabricating patterned W(18)O(49) nanowires in vertical arrays and on a large scale. These W(18)O(49) nanowire arrays have an average diameter of about 30 nm, and their lengths range from 2-3 μm. In every pattern of a 2 inch sample, the nanowires exhibit the same morphology and growth density. They are single crystals with monoclinic structure and grow along the [010] direction. Field emission (FE) measurements show that they have a turn-on field of 6.2 V μm(-1) and their emission current density can reach 500 μA cm(-2) at an electric field of 10.9 V μm(-1). Because the W(18)O(49) nanowire patterns synthesized by this simple method still have good FE performance, comparable to many cathode nanostructures with excellent FE properties, it suggests that it may provide an effective and simple preparation technique for patterned growth of nanowire arrays in future FE applications.

Controlled synthesis of ultra-long AlN nanowires in different densities and in situ investigation of the physical properties of an individual AlN nanowire

The controlled synthesis of different growth densities of ultra-long AlN nanowires has been successfully realized by nitridation of Al powders for the first time. These AlN nanowires have an average diameter of about 100 nm and their mean length is over 50 μm. All the synthesized ultra-long nanowires are pure single crystalline h-AlN structures with a growth orientation of [0001]. We preferred the self-catalyzing vapor-liquid-solid (VLS) mechanism to illustrate their growth process. Although the sample with the middle growth density (3.2×10(7) per cm2) of AlN nanowire performs the best field emission (FE) properties, the emission uniformity is not good enough for field emission display applications, which may be attributed to their low intrinsic conductivity. Moreover, the electrical transport and FE properties of an individual ultra-long AlN nanowire are further investigated in situ to find the decisive factor responsible for their FE behaviors. An individual AlN nanowire is observed to have a mean 1 nA field of 440 V μm(-1) and 1 μA field of 480 V μm(-1) as well as an average electrical conductivity of about 2.7×10(-4)Ω(-1) cm(-1), which is lower than that of some cathode materials with excellent FE properties. Therefore we come to the conclusion that the electrical conductivity of the AlN nanowire must be improved to a higher level by some effective ways in order to realize their practical FE device applications.

Experimental study on genistein prevention and treatment of transplant arteriosclerosis in aortic transplants of rat

OBJECTIVE

Our objective was to study the effects of genistein, a soy isoflavone, on transplant arteriosclerosis, in addition to its immunosuppressive and antioxidant properties.

MATERIALS AND METHODS

We performed male Brown-Norway to male Lewis aortic transplantation. The recipients were randomly assigned to 3 groups: no treatment controls, dimethyl sulfoxide (DMSO; 5 mL/kg) solvent controls, and experimental group that received genistein (20 mg/kg/d) by daily intraperitoneal injection. On postoperative day 60, the graft was harvested and blood obtained. The transplanted aorta was analyzed by histology and immunohistochemistry. The serum was analyzed by an enzyme-linked immunosorbent assay (ELISA).

RESULTS

Compared with the 2 controls, leukocyte recruitment to the graft was significantly inhibited by genistein, with a profound reduction in the number of CD69 macrophages infiltrating the adventitia of the transplanted aortas. Moreover, genistein significantly inhibited the expression of VEGF and IFN-gamma production (P < .01).

CONCLUSION

These results suggested that the protein tyrosine kinase inhibitor genistein inhibited graft arteriosclerosis.

The survival and value of liver transplantation for liver carcinoma: a single-center experience

Liver transplantation for liver carcinoma with cirrhosis is a treatment still in dispute. The objectives were to summarize the survival and cost of 50 liver transplant cases performed for liver carcinoma over nearly 3 years.

METHODS

We performed 138 liver transplants from January 1999 to February 2002. There were 50 cases (36.2%) of liver carcinoma with HBV cirrhosis, which were divided into three stages based on the tumor pathology: Stage 1 cases showed a single mass (< or = 5 cm), 4 cases; Stage 2, a single mass > 5 cm or intrahepatic multiple masses without PV cancer embolus, 32 cases; and Stage 3: tumor invasion of the PV or perihepatic lymph nodes or organs, 14 cases. All patients received three to six courses of chemotherapy postoperatively.

RESULTS

All four cases of stage 1 survived > 1 year; one of them is at 3 years with good liver function and tumor free. The mean half-year medical cost was $27.100 +/- 108 in stage 1. The half-year survival and medical costs were 62.5% and $31,500 +/- 260 in stage 2 and 15.0% and $35,500 +/- 134 in stage 3.

CONCLUSION

Liver transplantation is an effective treatment for early-stage liver carcinoma, that achieves good medical and economic results, but should be limited to advanced liver cancer.

MRP subfamily transporters and resistance to anticancer agents

The MRP subfamily of ABC transporters from mammals consists of at least seven members, six of which have been implicated in the transport of amphipathic anions. MRP1, MRP2, and MRP3 bear a close structural resemblance, confer resistance to a variety of natural products as well as methotrexate, and have the facility for transporting glutathione and glucuronate conjugates. MRP1 is a ubiquitously expressed efflux pump for the products of phase II of xenobiotic detoxification, while MRP2, whose hereditary deficiency results in Dubin-Johnson syndrome, functions to extrude organic anions into the bile. MRP3 is distinguished by its capacity to transport the monoanionic bile constituent glycocholate, and may function as a basolateral back-up system for the detoxification of hepatocytes when the usual canalicular route is impaired by cholestatic conditions. MRP4 and MRP5 resemble each other more closely than they resemble MRPs 1-3 and confer resistance to purine and nucleotide analogs which are either inherently anionic, as in the case of the anti-AIDS drug PMEA, or are phosphorylated and converted to anionic amphiphiles in the cell, as in the case of 6-MP. Given their capacity for transporting cyclic nucleotides, MRP4 and MRP5 have also been implicated in a broad range of cellular signaling processes. The drug resistance activity and physiological substrates of MRP6 are unknown. However, its hereditary deficiency results in pseudoxanthoma elasticum, a multisystem disorder affecting skin, eyes, and blood vessels. It is hoped that elucidation of the resistance profiles and physiological functions of the different members of the MRP subfamily will provide new insights into the molecular basis of clinical drug resistance and spawn new strategies for combating this phenomenon.

Transport of methotrexate (MTX) and folates by multidrug resistance protein (MRP) 3 and MRP1: effect of polyglutamylation on MTX transport

We have recently determined that human multidrug resistance protein (MRP) 3, which confers resistance to certain natural product agents and methotrexate (MTX), is competent in the MgATP-energized transport of MTX and the monoanionic bile constituent glycocholate as well as several glutathione and glucuronate conjugates. Of these capabilities, the facility of MRP3 in conferring resistance to and mediating the transport of MTX is of particular interest because it raises the possibility that this pump is a component of the previously described cellular efflux system for this antimetabolite. However, if this is to be the case, a critical property of cellular MTX efflux that must be addressed is its ability to mediate the export of MTX but not that of its intracellular polyglutamylated derivatives. Here we examine the role of MRP3 in these and related processes by determining the selectivity of this transporter for MTX, MTX polyglutamates, and physiological folates. In so doing, we show that MRP3 is not only active in the transport of MTX but is also active in the transport the physiological folates folic acid (FA) and N(5)-formyltetrahydrofolic acid (leucovorin) and that polyglutamylation of MTX abolishes transport. Both FA and leucovorin are subject to high-capacity (V(max(FA)), 1.71 +/- 0.05 nmol/mg/min; V(max(leucovorin)), 3.63 +/- 1.20 nmol/mg/min), low-affinity (K(m(FA)), 1.96 +/- 0.13 mM; K(m(leucovorin)), 1.74 +/- 0.65 mM) transport by MRP3. Addition of a single glutamyl residue to MTX is sufficient to diminish transport by >95%. We also show that polyglutamylation similarly affects the capacity of MRP1 to transport MTX and that physiological folates are also subject to MgATP-stimulated transport by MRP1. On the basis of the capacity to transport MTX but not MTX-Glu(2), it is concluded that MRP3 and MRP1 represent components of the previously described cellular efflux system for MTX. The capacity of MRP3 to transport folates indicates that it may reduce intracellular levels of these compounds and thereby indirectly influence antifolate cytotoxicity, and it also implies that this pump may play a role in the response to chemotherapeutic regimens in which leucovorin is a component.

Prognostic significance of multidrug resistance protein in adult T-cell leukemia

The response of adult T-cell leukemia (ATL) to chemotherapy is poor, and a major obstacle to successful treatment is intrinsic or acquired drug resistance. To determine the clinical significance of multidrug resistance protein (MRP) 1 in ATL, we studied MRP1 expression and its association with clinical outcome. The expression of MRP1 mRNA in leukemia cells from 48 ATL patients was studied by slot blot analysis. The expression level of MRP1 mRNA in chronic-type ATL was significantly higher than that in lymphoma-type ATL (P = 0.033). There was no correlation between MRP1 expression and age, gender, WBC count, LDH, hypercalcemia, blood urea nitrogen, or performance status. However, the expression of MRP1 mRNA correlated only with peripheral blood abnormal lymphocyte counts (P = 0.008). The transporting activity of MRP1 was assessed using membrane vesicles. Membrane vesicles prepared from ATL cells with high expression of MRP1 mRNA showed a higher ATP-dependent leukotriene C(4) uptake than did those with low expression of MRP1 mRNA. This uptake was almost completely inhibited by LTD(4) antagonists ONO-1078 and MK571. In acute- and lymphoma-type ATL, high expression of MRP1 mRNA at diagnosis correlated with shorter survival, and Cox regression analysis revealed that MRP1 expression was an independent prognostic factor. These findings suggest that functionally active MRP1 is expressed in some ATL cells and that it is involved in drug resistance and has a possible causal relationship with poor prognosis in ATL. Multidrug resistance-reversing agents, such as ONO-1078 and MK571, that directly interact and inhibit the transporting activity of MRP1 may be useful for treating ATL patients.

Transport of cyclic nucleotides and estradiol 17-beta-D-glucuronide by multidrug resistance protein 4. Resistance to 6-mercaptopurine and 6-thioguanine

Human multidrug resistance protein 4 (MRP4) has recently been determined to confer resistance to the antiviral purine analog 9-(2-phosphonylmethoxyethyl)adenine and methotrexate. However, neither its substrate selectivity nor physiological functions have been determined. Here we report the results of investigations of the in vitro transport properties of MRP4 using membrane vesicles prepared from insect cells infected with MRP4 baculovirus. It is shown that expression of MRP4 is specifically associated with the MgATP-dependent transport of cGMP, cAMP, and estradiol 17-beta-D-glucuronide (E(2)17 beta G). cGMP, cAMP, and E(2)17 beta G are transported with K(m) and V(max) values of 9.7 +/- 2.3 microm and 2.0 +/- 0.3 pmol/mg/min, 44.5 +/- 5.8 microm and 4.1 +/- 0.4 pmol/mg/min, and 30.3 +/- 6.2 microm and 102 +/- 16 pmol/mg/min, respectively. Consistent with its ability to transport cyclic nucleotides, it is demonstrated that the MRP4 drug resistance profile extends to 6-mercaptopurine and 6-thioguanine, two anticancer purine analogs that are converted in the cell to nucleotide analogs. On the basis of its capacity to transport cyclic nucleotides and E(2)17 beta G, it is concluded that MRP4 may influence diverse cellular processes regulated by cAMP and cGMP and that its substrate range is distinct from that of any other characterized MRP family member.

Elevated expression of vacuolar proton pump genes and cellular PH in cisplatin resistance

V-ATPases are proton-translocating enzymes, which are found not only in numerous intracellular organelles but also in the plasma membranes of many eukaryotic cells. Using differential display, we have identified one of the proton pump subunit genes, ATP6C, as a cisplatin-inducible gene. Northern blot analysis demonstrated that expression of other members of the subunit is inducible by cisplatin treatment. Proton pump gene expression is also upregulated in 3 independent cisplatin-resistant cell lines but not in vincristine- or etoposide-resistant cell lines. Cellular pH was significantly higher in cisplatin-resistant cells than in sensitive parental cells. In vitro DNA-binding activity of cisplatin was markedly increased in acidic conditions, suggesting that the cytotoxicity of cisplatin is modulated by cellular pH. Furthermore, the proton pump inhibitor bafilomycin can synergistically potentiate the cytotoxicity of cisplatin but not of etoposide or camptothecin. These results indicate that cellular pH is one of the critical parameters for effective cancer chemotherapy with cisplatin.

Reversing effect of agosterol A, a spongean sterol acetate, on multidrug resistance in human carcinoma cells

The effect of agosterol A, a novel polyhydroxylated sterol acetate isolated from a marine sponge, on P-glycoprotein (P-gp)-mediated multidrug-resistant cells (KB-C2) and the multidrug resistance associated protein (MRP1)-mediated multidrug-resistant cells (KB-CV60) was examined. Agosterol A reversed the resistance to colchicine in KB-C2 cells and also the resistance to vincristine in KB-CV60 cells at 3 to 10 microM concentration. Agosterol A at 3 mM increased the vincristine concentration in both KB-C2 cells and KB-CV60 cells to the level in parental KB-3-1 cells. Agosterol A also decreased the efflux of vincristine from both KB-C2 cells and KB-CV60 cells to the level seen in KB-3-1 cells. Agosterol A inhibited the [(3)H]azidopine-photolabeling of P-gp and also inhibited the uptake of [(3)H]S-(2,4-dinitrophenyl)glutathione (DNP-SG) in inside-out membrane vesicles prepared from KB-CV60 cells. We conclude that agosterol A directly inhibited drug efflux through P-gp and/or MRP1.

Reversal of drug resistance mediated by multidrug resistance protein (MRP) 1 by dual effects of agosterol A on MRP1 function

We previously isolated agosterol A (AG-A) from a marine Spongia sp. and found that it completely reversed colchicine resistance in P-glycoprotein (Pgp)-over-expressing KB-C2 cells and vincristine resistance in multidrug-resistance protein (MRP)1-over-expressing CV60 cells. However, a tri-deacetylated derivative of AG-A (IAG-A) showed almost no activity in reversing Pgp- or MRP1-mediated drug resistance. In this study, we examined the mechanisms by which AG-A reverses MRP1-mediated drug resistance by investigating the interaction between agosterols and MRP1 in MRP1-over-expressing human KB carcinoma (KB/MRP) cells. [3H]-Leukotriene C4 (LTC4), [3H]-2,4-dinitrophenyl-S-glutathione uptake into membrane vesicles prepared from KB/MRP cells and intracellular [3H]-vincristine accumulation and efflux in KB/MRP cells were measured with or without AG-A and/or inactive IAG-A. AG-A reduced MRP1-mediated [3H]-LTC4 transport in a dose-dependent manner, but IAG-A did not. Inhibition by AG-A was competitive, with a K(i) value of 31 microM. AG-A at 10 microM enhanced the accumulation of [3H]-vincristine in KB/MRP cells to the level of that in control cells in the absence of the agent. Likewise, ATP-dependent efflux of [3H]-vincristine from KB/MRP cells was enhanced compared with KB-3-1 cells and inhibited by AG-A. In addition, AG-A reduced intracellular levels of glutathione, a compound required for MRP1-mediated transport of some anti-cancer drugs. These findings suggest that AG-A reverses MRP1-mediated drug resistance by directly inhibiting the capacity of MRP1 to transport drugs. In addition, the capacity of AG-A to reduce cellular glutathione levels may contribute to the modulating activity of MRP1.

Glutathione-dependent binding of a photoaffinity analog of agosterol A to the C-terminal half of human multidrug resistance protein

MRP1 is a 190-kDa membrane glycoprotein that confers multidrug resistance (MDR) to tumor cells. MRP1 is characterized by an N-terminal transmembrane domain (TMD(0)), which is connected to a P-glycoprotein-like core region (DeltaMRP) by a cytoplasmic linker domain zero (L(0)). It has been demonstrated that GSH plays an important role in MRP1-mediated MDR. However, the mechanism by which GSH mediates MDR and the precise roles of TMD(0) and L(0) are not known. We synthesized [(125)I]11-azidophenyl agosterol A ([(125)I]azidoAG-A), a photoaffinity analog of the MDR-reversing agent, agosterol A (AG-A), to photolabel MRP1, and found that the analog photolabeled the C-proximal molecule of MRP1 (C(932-1531)) in a manner that was GSH-dependent. The photolabeling was inhibited by anticancer agents, reversing agents and leukotriene C(4). Based on photolabeling studies in the presence and absence of GSH using membrane vesicles expressing various truncated, co-expressed, and mutated MRP1s, we found that L(0) is the site on MRP1 that interacts with GSH. This study demonstrated that GSH is required for the binding of an unconjugated agent to MRP1 and suggested that GSH interacts with L(0) of MRP1. The photoanalog of AG-A will be useful for identifying the drug binding site within MRP1, and the role of GSH in transporting substrates by MRP1.

Prediction of soil depth using a soil-landscape regression model: a case study on forest soils in southern Taiwan

Techniques for conventional forest soil surveys in Taiwan need to be further developed in order to save time and money. Although some soil-landscape regression models have been developed to describe and predict soil properties and depths, they have seldom been studied in Taiwan. This study establishes linear soil-landscape regression models related to soil depths and landscape factors found in the forest soils of southern Taiwan. These models were evaluated by validating the models according to their mean errors and root mean square errors. The study was carried out at the 60,000 ha Chishan Forest Working Circle. About 310 soil pedons were collected. The landscape factors included elevation, slope, aspect, and surface stone contents. Sixty percent of the total field samples were used to establish the soil-landscape regression models, and forty % were used for validation. The sampling strategy indicated that each representative pedon covers an area of about 147 ha. The number of samples was appropriate considering the available time and budget. The single variate and/or multivariate linear regression soil-landscape models were successfully established. Those models revealed significant inter-relations among the soil depths of the B and B+BC horizons, solum thickness, and landscape factors, including slope and surface stone contents (p < 0.003). The mean errors in the validation of the soil-landscape model were low and acceptable for this case study. In addition, the slope data derived from the DEM (digital elevation model) database in this case study were used to predict the soil depths of the B, B+BC horizons and the solum thickness without carrying out a field survey. Surface stone should be collected in a field soil survey to increase the precision of soil depth prediction of the B and B+BC horizons, and the solum thickness.