Combinatorial screening for therapeutics in ATTRv amyloidosis identifies naphthoquinone analogues as TTR-selective amyloid disruptors.

Hereditary ATTR amyloidosis is caused by the point mutation in serum protein transthyretin (TTR) that destabilizes its tetrameric structure to dissociate into monomer. The monomers form amyloid fibrils, which are deposited in peripheral nerves and organs, resulting in dysfunction. Therefore, a drug that dissolves amyloid after it has formed, termed amyloid disruptor, is needed as a new therapeutic drug. Here, we first established a high throughput screening system to find TTR interactors from the LOPAC1280 compound library. Among the hit compounds, thioflavin T-based post-treatment assay determined lead compounds for TTR amyloid disruptors, NSC95397 and Gossypol, designated as B and R, respectively. Because these compounds have naphthoquinone-naphthalene structures, we tested 100 naphthoquinone derivatives, and found 10 candidate compounds that disrupted TTR amyloid. Furthermore, to determine whether these 10 compounds are selective for TTR amyloid, we evaluated them against beta-amyloid (Aß1-42). We found two compounds that were selective for TTR and did not disrupt Aß-derived amyloid. Therefore, we succeeded in identifying TTR-selective amyloid disruptors, and demonstrated that naphthoquinone compounds are useful structures as amyloid disruptors. These findings contribute to the on-going efforts to discover new therapeutic tools for TTR amyloidosis.

Novel Keap1-Nrf2 Protein-Protein Interaction Inhibitor UBE-1099 Ameliorates Progressive Phenotype in Alport Syndrome Mouse Model.

Background: Bardoxolone methyl activates nuclear factor erythroid 2-related factor 2 (Nrf2) via covalent binding and irreversible inhibition of Kelch-like ECH-associated protein 1 (Keap1), the negative regulator of Nrf2. Ongoing clinical trials of bardoxolone methyl show promising effects for patients with CKD. However, the direct inhibition of Keap1-Nrf2 protein-protein interaction (PPI) as an approach to activate Nrf2 is less explored. Methods: We developed a noncovalent Nrf2 activator UBE-1099, which highly selectively inhibits Keap1-Nrf2 PPI, and evaluated its efficacy on the progressive phenotype in an Alport syndrome mouse model (Col4a5-G5X). Results: Similar to bardoxolone methyl, UBE-1099 transiently increased proteinuria and reduced plasma creatinine in Alport mice. Importantly, UBE-1099 improved the glomerulosclerosis, renal inflammation, and fibrosis, and prolonged the life span of Alport mice. UBE-1099 ameliorated the dysfunction of Nrf2 signaling in the renal tissue of Alport mice. Moreover, transcriptome analysis in the glomerulus showed that UBE-1099 induced the expression of genes associated with the cell cycle and cytoskeleton, which may explain its unique mechanism of improvement such as glomerular morphologic change. Conclusions: UBE-1099 significantly ameliorates the progressive phenotype in Alport mice. Our results revealed the efficacy of Keap1-Nrf2 PPI inhibitor for glomerulosclerosis and present a potential therapeutic drug for CKD.

Involvement of Parkin-mediated mitophagy in the pathogenesis of chronic obstructive pulmonary disease-related sarcopenia.

BACKGROUND: Sarcopenia is characterized by the loss of skeletal muscle mass and strength and is associated with poor prognosis in patients with chronic obstructive pulmonary disease (COPD). Cigarette smoke (CS) exposure, a major cause for COPD, induces mitochondrial damage, which has been implicated in sarcopenia pathogenesis. The current study sought to examine the involvement of insufficient Parkin-mediated mitophagy, a mitochondrion-selective autophagy, in the mechanisms by which dysfunctional mitochondria accumulate with excessive reactive oxygen species (ROS) production in the development of COPD-related sarcopenia. METHODS: The involvement of Parkin-mediated mitophagy was examined using in vitro models of myotube formation, in vivo CS-exposure model using Parkin-/- mice, and human muscle samples from patients with COPD-related sarcopenia. RESULTS: Cigarette smoke extract (CSE) induced myotube atrophy with concomitant 30% reduction in Parkin expression levels (P < 0.05). Parkin-mediated mitophagy regulated myotube atrophy by modulating mitochondrial damage and mitochondrial ROS production. Increased mitochondrial ROS was responsible for myotube atrophy by activating Muscle Ring Finger 1 (MuRF-1)-mediated myosin heavy chain (MHC) degradation. Parkin-/- mice with prolonged CS exposure showed enhanced limb muscle atrophy with a 31.7% reduction in limb muscle weights (P < 0.01) and 2.3 times greater MuRF-1 expression (P < 0.01) compared with wild-type mice with concomitant accumulation of damaged mitochondria and oxidative modifications in 4HNE expression. Patients with COPD-related sarcopenia exhibited significantly reduced Parkin but increased MuRF-1 protein levels (35% lower and 2.5 times greater protein levels compared with control patients, P < 0.01 and P < 0.05, respectively) and damaged mitochondria accumulation demonstrated in muscles. Electric pulse stimulation-induced muscle contraction prevented CSE-induced MHC reduction by maintaining Parkin levels in myotubes. CONCLUSIONS: Taken together, COPD-related sarcopenia can be attributed to insufficient Parkin-mediated mitophagy and increased mitochondrial ROS causing enhanced muscle atrophy through MuRF-1 activation, which may be at least partly preventable through optimal physical exercise.

A cell-based high-throughput screening method to directly examine transthyretin amyloid fibril formation at neutral pH.

Transthyretin (TTR) is a major amyloidogenic protein associated with hereditary (ATTRm) and nonhereditary (ATTRwt) intractable systemic transthyretin amyloidosis. The pathological mechanisms of ATTR-associated amyloid fibril formation are incompletely understood, and there is a need for identifying compounds that target ATTR. C-terminal TTR fragments are often present in amyloid-laden tissues of most patients with ATTR amyloidosis, and on the basis of in vitro studies, these fragments have been proposed to play important roles in amyloid formation. Here, we found that experimentally-formed aggregates of full-length TTR are cleaved into C-terminal fragments, which were also identified in patients' amyloid-laden tissues and in SH-SY5Y neuronal and U87MG glial cells. We observed that a 5-kDa C-terminal fragment of TTR, TTR81-127, is highly amyloidogenic in vitro, even at neutral pH. This fragment formed amyloid deposits and induced apoptosis and inflammatory gene expression also in cultured cells. Using the highly amyloidogenic TTR81-127 fragment, we developed a cell-based high-throughput screening method to discover compounds that disrupt TTR amyloid fibrils. Screening a library of 1280 off-patent drugs, we identified two candidate repositioning drugs, pyrvinium pamoate and apomorphine hydrochloride. Both drugs disrupted patient-derived TTR amyloid fibrils ex vivo, and pyrvinium pamoate also stabilized the tetrameric structure of TTR ex vivo in patient plasma. We conclude that our TTR81-127-based screening method is very useful for discovering therapeutic drugs that directly disrupt amyloid fibrils. We propose that repositioning pyrvinium pamoate and apomorphine hydrochloride as TTR amyloid-disrupting agents may enable evaluation of their clinical utility for managing ATTR amyloidosis.

Transthyretin Amyloid Fibril Disrupting Activities of Extracts and Fractions from Juglans mandshurica Maxim. var. cordiformis (Makino) Kitam.

Transthyretin-related amyloidosis is a slowly progressive disorder caused by deposition of insoluble amyloid plaques formed by fibrillization of mutant or defective transthyretin (TTR) monomers that leads to neurodegeneration and organ failure. Thus, any compound exhibiting TTR amyloid formation inhibitory activity or TTR amyloid fibril disrupting activity might be a potential candidate for the development of therapies for these disorders. Our aim in this study was the evaluation of the TTR amyloid fibril disrupting potential of extracts of leaves and immature fruits of two Juglans plants, i.e., Juglans mandshurica var. sachalinensis and Juglans mandshurica var. cordiformis. The TTR amyloid fibril disrupting activity was measured by Thioflavin-T (ThT) assay and PROTEOSTAT® Protein aggregation assay methods. A fifty percent acetone extract of the fruits of Juglans mandshurica var. cordiformis showed strong amyloid fibril disrupting activity, and was further fractionated using different solvents. Ethyl acetate and n-butanol fractions showed significant activity in both assays. Syringic acid was isolated and identified as main compound in both of these fractions; however, it did not show any activity. Furthermore, some of the previously reported compounds from Juglans plants including naphthoquinone derivatives and phenolic compounds were evaluated to identify the potential bioactive compounds. Among them, juglone, a naphthoquinone derivative showed promising activity. However, juglone also showed strong cytotoxicity in HEK293 cells. Thus, future studies should focus on the isolation and identification of naphthoquinone derivatives or other compounds from Juglans plan ts with potent bioactivity and low cytotoxicity.

Characterization of Non-amyloidogenic G101S Transthyretin.

Transthyretin (TTR) is a tetrameric beta-sheet-rich protein that is important in the plasma transport of thyroxine and retinol. Mutations in the TTR gene cause TTR tetramer protein to dissociate to monomer, which is the rate-limiting step in familial amyloid polyneuropathy. Amyloidogenicity of individual TTR variants depends on the types of mutation that induce significant changes in biophysical, biochemical and/or biological properties. G101S TTR variant was previously identified in a Japanese male without amyloidotic symptom, and was considered as a non-amyloidogenic TTR variant. However, little is known about G101S TTR. Here, we found slight but possibly important biophysical differences between wild-type (WT) and G101S TTR. G101S TTR had slower rate of tetramer dissociation and lower propensity for amyloid fibril formation, especially at mild low pH (4.2 and 4.5), and was likely to have strong hydrophobic interaction among TTR monomers, suggesting relatively higher stability of G101S TTR compared with WT TTR. Cycloheximide (CHX)-based assay in HEK293 cells revealed that intracellular G101S TTR expression level was lower, but extracellular expression was higher than WT TTR, implying enhanced secretion efficiency of G101S TTR protein compared with WT TTR. Moreover, we found that STT3B-dependent posttranslational N-glycosylation at N98 residue occurred in G101S TTR but not in other TTR variants, possibly due to amino acid alterations that increase N-glycosylation preference or accelerate rigid structure formation susceptible to N-glycosylation. Taken together, our study characterizes G101S TTR as a stable and N-glycosylable TTR, which may be linked to its non-amyloidogenic characteristic.

Mild Lung Tuberculosis in a Patient Suffering from Status Epilepticus Caused by the Syndrome of Inappropriate Secretion of Antidiuretic Hormone (SIADH).

A 76-year-old woman was diagnosed with lung tuberculosis. On the second day of anti-tuberculosis treatment, she became unconscious and developed status epilepticus accompanied by hyponatremia. The hyponatremia was caused by the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). Detailed examinations revealed that the patient's status epilepticus had occurred due to hyponatremia, which was caused by lung tuberculosis-associated SIADH. Previous case reports noted that patients with tuberculosis-associated SIADH showed mild clinical manifestations. They also reported that extensive lung involvement was associated with SIADH development. We herein report a rare case of SIADH complicated with status epilepticus that was caused by tuberculosis with mild lung involvement.

Adjuvant surgery for advanced extrahepatic cholangiocarcinoma.

Patients with Stage IV cholangiocarcinoma are currently not considered to be surgical candidates and are typically offered systemic chemotherapy. Recently, several novel systemic chemotherapy regimens have allowed an initially unresectable cholangiocarcinoma to be resectable. The aim of this article is to present the usefulness of adjuvant surgery in a case of advanced cholangiocarcinoma that was successfully treated with gemcitabine. A 72-year-old man was diagnosed with distal cholangiocarcinoma with liver metastases (cT2N0M1, Stage IV). He underwent metal stent placement in the duodenum to alleviate jaundice. After 18 courses of chemotherapy using gemcitabine without severe drug toxicities, a computed tomography scan showed that the liver metastases in S6 and S7 had disappeared. The patient underwent subtotal stomach-preserving pancreaticoduodenectomy and lymph node dissection. The pathological stage was pT2N0M0, Stage IB. The patient underwent 6 cycles of adjuvant chemotherapy using gemcitabine. The patient is alive and well 6 years and 9 mo after the diagnosis.

A novel preoperative fusion analysis using three-dimensional MDCT combined with three-dimensional MRI for patients with hilar cholangiocarcinoma.

The purpose of the present study was to evaluate the anatomical relationship between the tumor, portal veins, hepatic arteries, and hilar hepatic ducts at the hepatic hilum using a novel preoperative fusion analysis for patients with hilar cholangiocarcinoma. This involved combining three-dimensional multidetector-row computed tomography with three-dimensional magnetic resonance imaging. This novel fusion imaging technique can play an important clinical role for patients undergoing surgery for hilar cholangiocarcinoma.

Platelet transfusion improves liver function in patients with chronic liver disease and cirrhosis.

Chronic liver disease (CLD), such as hepatitis C, is a progressive disease consisting of the destruction and regeneration of the liver parenchyma, leading to fibrosis and cirrhosis. Platelets contain various growth factors and may play important roles in liver regeneration. Thus, to investigate whether platelet transfusion improves liver function in patients with CLD and cirrhosis, we conducted an exploratory clinical trial. The study included 10 patients with CLD and cirrhosis (Child-Pugh class A or B), who all presented thrombocytopenia (platelet counts between 50,000 and 100,000 /µl). The subjects received 10 units of platelet concentrate once a week for 12 weeks. They were followed up for 9 months after the last transfusion. One patient discontinued platelet transfusion because of pruritus, and 2 patients discontinued because of platelet transfusion refractoriness. One patient was excluded from the analysis for receiving a procedural treatment after 12 platelet transfusions. Thus, the remaining 6 patients were analyzed. The platelet count did not increase significantly after the last transfusion. Significant improvement of serum albumin was observed at 1 month and 3 months after the last transfusion. Serum cholinesterase improved significantly at 1 week, 3 months, and 9 months after the last transfusion. Serum hyaluronic acid showed a tendency toward improvement after the last transfusion. In conclusion, platelet transfusion improved some of the indicators of liver function in patients with CLD and cirrhosis, though adverse events related to platelet transfusion were observed in some patients. Platelet increment therapy could be a new strategy for treating CLD and cirrhosis.

Analysis of the caudate artery with three-dimensional imaging.

BACKGROUND/PURPOSE: To date there have been only a few radiological studies of the caudate artery. This study aimed to precisely analyze the caudate artery as well as the relationship between the caudate arteries, the arterial plexus at the hilar plate, and the hilar bile duct. METHODS: Reconstructed three-dimensional (3D) computed tomography images from 50 patients during hepatic arteriography were analyzed. The caudate arteries were classified as right branches (Irs) or left branches (Ils). The communicating artery (CA) was defined as the artery connecting the right, left, segmental, and common hepatic arteries. RESULTS: The caudate artery was divided into 3 types: an independent branch (Type 1); the common tract formed by Ir and Il (Type 2); and an arterial branch from the CA (Type 3). The CA was recognized in 25 of 50 patients. There was a total of 65 arteries to the hilar bile duct observed in 40 patients, and 24 (37 %) of these 65 arteries to the hilar bile duct originated from the caudate artery or CA. CONCLUSION: The caudate artery plays an important role not only in connecting the blood supply of the right and left livers but in the blood supply to the hilar bile duct.

Inflammation-based prognostic score is a useful predictor of postoperative outcome in patients with extrahepatic cholangiocarcinoma.

BACKGROUND/PURPOSE: Recent studies have revealed that the Glasgow prognostic score (GPS), an inflammation-based prognostic score, is useful for predicting outcome in a variety of cancers. This study sought to investigate the significance of GPS for prognostication of patients who underwent surgery with extrahepatic cholangiocarcinoma. METHODS: We retrospectively analyzed a total of 62 patients who underwent resection for extrahepatic cholangiocarcinoma. We calculated the GPS as follows: patients with both an elevated C-reactive protein (>10 mg/L) and hypoalbuminemia (<35 g/L) were allocated a score of 2; patients with one or none of these abnormalities were allocated a s ore of 1 or 0, respectively. Prognostic significance was analyzed by the log-rank test and a Cox proportional hazards model. RESULTS: Overall survival rate was 25.5 % at 5 years for all 62 patients. Venous invasion (p = 0.01), pathological primary tumor category (p = 0.013), lymph node metastasis category (p < 0.001), TNM stage (p < 0.001), and GPS (p = 0.008) were significantly associated with survival by univariate analysis. A Cox model demonstrated that increased GPS was an independent predictive factor with poor prognosis. CONCLUSIONS: The preoperative GPS is a useful predictor of postoperative outcome in patients with extrahepatic cholangiocarcinoma.

Recognition of other organ involvement might assist in the differential diagnosis of IgG4-associated sclerosing cholangitis without apparent pancreatic involvement: report of two cases.

IgG4-associated sclerosing cholangitis (IAC) was recently defined as biliary involvement of IgG4-related systemic disease. It is frequently associated with autoimmune pancreatitis, characterized by pancreatic enlargement and irregular narrowing of the pancreatic duct. However, a few cases of IAC with no apparent pancreatic involvement have been described, the characteristics of which may mimic those of cholangiocarcinoma. We report two rare cases of IgG4-associated sclerosing cholangitis at the hepatic hilum, mimicking hilar cholangiocarcinoma. When trying to establish the diagnosis, we should consider other organs that could be involved, such as the pancreas, salivary glands, retroperitoneum, lymph nodes, and kidneys, as well as chronic inflammatory changes. By recognizing these lesions and measuring serum IgG4, IAC can be diagnosed correctly, thereby avoiding unnecessary major surgery for a condition that is treated effectively by steroid therapy.

Effective delivery of chemotherapeutic nanoparticles by depleting host Kupffer cells.

Although chemotherapeutic nanoparticles would confer various advantages, the majority of administrated nanoparticles are known to be spoiled by the reticuloendothelial system (RES). Intending to more effectively deliver therapeutic nanoparticles to target regions in vivo, host RES, especially Kupffer cells in the liver, have been depleted ahead of drug administration. To demonstrate this hypothesis, clodronate liposomes were preinjected into BALB/c nude mice for depletion of Kupffer cells 2 days before, and pegylated liposomal doxorubicin (Doxil) at the doses of 1.25, 2.5 and 5.0 mg/kg was administered. As a result, doxorubicin accumulation in the liver was decreased from 36 to 26% injected dose/organ by the Kupffer cells depletion, and consequently, the plasma concentration of doxorubicin was significantly enhanced threefold (from 11 to 33 µg/mL) on day 1 at 1.25 mg/kg-dose group. Doxorubicin accumulation in the tumor was increased from 0.78 to 3.0 µg/g-tissue on day 3, and tumor growth inhibition by Doxil was significantly boosted (tumor volumes from 751 to 482 mm(3) on day 24) by the Kupffer cells depletion. In conclusion, Kupffer cells depletion by clodronate liposomes enhanced the plasma concentration and antitumor effects of Doxil, and would be widely applicable for various clinical cancer chemotherapies using nanoparticles.

Invasion of the hepatic artery is a crucial predictor of poor outcomes in gallbladder carcinoma.

BACKGROUND: In the present study we undertook a retrospective analysis of gallbladder carcinoma to assess whether histologically determined hepatic artery (HA) invasion and portal vein (PV) invasion can be considered prognostic factors. METHODS: Seventy-one patients who had undergone radical resection for gallbladder carcinoma between 1995 and 2008 at University of Tsukuba were selected from the database for analysis. Patients who required extended surgery for para-aortic lymph node metastasis were also included. Correlation between invasion of the HA and the PV and prognosis and other clinicopathologic factors were analyzed. RESULTS: There were two postoperative deaths among the 71 patients. Pathological invasion of the HA was confirmed in 16 (22.5%) cases and PV invasion was confirmed in 15 patients. Patients with invasion of the HA had a significantly poorer prognosis than those without HA invasion (P < 0.0001). Additionally, in univariate analysis, gender (male), positive para-aortic lymph node metastasis, PV invasion, and HA invasion were identified as significant poor prognostic factors. In multivariate analysis, only HA invasion was an independent prognostic factor (Odds Ratio 0.323; P = 0.029). CONCLUSIONS: Invasion of the HA is a crucial prognostic factor in patients with gallbladder carcinoma.

Platelet-derived adenosine 5'-triphosphate suppresses activation of human hepatic stellate cell: In vitro study.

AIM: Activated hepatic stellate cells (HSC) play a critical role in liver fibrosis. Suppressing abnormal function of HSC or reversion from activated to quiescent form is a hopeful treatment for liver cirrhosis. The interaction between platelets and HSC remains unknown although platelets go through hepatic sinusoids surrounded by HSC. This study aimed at clarifying the hypothesis that platelets control activation of HSC. METHODS: We used human platelets, platelet extracts, and primary or immortalized human HSC. We examined the effect of platelets on the activation, DNA synthesis, type I collagen production, and fibrosis-relating gene expressions of HSC. We investigated what suppressed activation of HSC within platelets and examined the mechanism of controlling activation in vitro. RESULTS: Platelets and platelet extracts suppressed activation of HSC. Platelets decreased type I collagen production without affecting DNA synthesis. Platelets increased the expression of matrix metallopeptidase 1. As platelet extracts co-cultured with an enzyme of degrading adenosine 5'-triphosphate (ATP) suppressed activation, we detected adenine nucleotides within platelets or on their surfaces and confirmed the degradation of adenine nucleotides by HSC and the production of adenosine. Adenosine and platelets increased the intracellular cyclic adenosine 5'-monophosphate (cAMP), which is important in quiescent HSC. A great amount of adenosine and ATP also suppressed activation of HSC. CONCLUSION: Activation of human HSC is suppressed by human platelets or platelet-derived ATP via adenosine-cAMP signaling pathway in vitro. Therefore, platelets have the possibility to be used in the treatment of liver cirrhosis.

Well-differentiated endocrine carcinoma originating from the bile duct in association with a congenital choledochal cyst.

We encountered a rare case of a well-differentiated endocrine carcinoma originating from the bile duct in association with a congenital choledochal cyst (CCC). The patient is a 28-year-old woman referred to our clinic for pruritus. Laboratory data showed mild elevation of serum hepatobiliary enzymes. Computed tomography and magnetic resonance imaging demonstrated pancreatobiliary maljunction and a Todani type IV-A CCC from the inferior bile duct to the bilateral intrahepatic bile ducts. A solid tumor was detected in the middle portion of the common bile duct. Pancreatoduodenectomy and total extrahepatic bile duct resection was performed. Based on pathologic and immunohistochemical examinations, a diagnosis of well-differentiated endocrine carcinoma was made according to the World Health Organization criteria. To our knowledge, this is the third report of a neuroendocrine tumor originating from the bile duct in association with a CCC.

Impact of three-dimensional analysis of multidetector row computed tomography cholangioportography in operative planning for hilar cholangiocarcinoma.

BACKGROUND: A detailed evaluation of portal triad structures, especially the biliary anatomy at the hepatic hilus, is essential to ensure curative resection for hilar cholangiocarcinoma. METHODS: Patients underwent 3-dimensional analysis using multidetector row computed tomography cholangioportography preoperatively. The number of bile duct orifices in the cut end of the hilar plate was estimated and compared with the actual number of bile ducts. Furthermore, the estimated length of the surgical margin and its relationship to the pathological margin status was evaluated. RESULTS: The number of bile duct orifices was correctly estimated in 14 of 19 patients. Of 18 hepatic ducts in which the estimated length of the hepatic side surgical margin was calculated 17 hepatic ducts (94.4%) were diagnosed pathologically as margin negative. CONCLUSIONS: This investigatory technique has the advantages of precise visualization of anatomic structures and multidirectional assessment of biliary branches and vessels, allowing improved operative planning for the treatment of hilar cholangiocarcinoma.

MR imaging of reactive lymphoid hyperplasia of the liver.

INTRODUCTION: Reactive lymphoid hyperplasia, also known as pseudolymphoma or nodular lymphoid lesion of the liver, is a rare benign lesion. It is mainly detected in the lung, stomach, small intestine, orbit, pancreas, skin, and breast. It remains difficult to distinguish reactive lymphoid hyperplasia from malignant disease clinically when it develops in the liver. CASE REPORT: We have recently encountered a patient with liver reactive lymphoid hyperplasia who had undergone colon cancer surgery. CONCLUSION: Preoperative MR imaging showed some useful findings indicating reactive lymphoid hyperplasia.