Anesthetic management of a giant paraganglioma resection: a case report.

BACKGROUND: Patients with pheochromocytomas are often diagnosed with acute myocardial infarction (AMI) due to initial symptoms of palpitations and chest tightness. We describe a case of AMI syndrome where a giant paraganglioma was unexpectedly identified. The anesthetic management of the paraganglioma resection was challenging and complex. CASE PRESENTATION: A 66-year-old woman was admitted to the emergency department for complaints of palpitations, chest tightness and vomiting. A laboratory test revealed that troponin I and N-terminal pro-brain natriuretic peptide levels were dramatically increased. Emergency percutaneous coronary angiography (CAG) showed normal coronary arteries. In addition, the serum levels of free catecholamines were increased, and computed tomography and magnetic resonance imaging revealed a heterogenous mass lesion in the right retroperitoneal. All of this ultimately confirmed the diagnosis of pheochromocytoma. After three weeks of careful preoperative preparation by a multidisciplinary team, and an anesthesiologist team develops detailed perianesthesia management strategies to maintain hemodynamics and blood glucose stability and regulate acid-base balance, pheochromocytoma resection was performed successfully. About 2 weeks later, the patient was discharged healthy. A postoperative pathology test confirmed paraganglioma. CONCLUSIONS: To our knowledge, giant pheochromocytoma resection is a complex challenge for the anesthesiologists, this clinical case may supply a thoughtful experience for anesthetic management in the resection of giant pheochromocytomas. Adequate preoperative evaluation and prudent perianesthesia management by anesthesiologists are important guarantees for patients to obtain a good prognosis and discharge healthily.

Dysregulated SREBP1c/miR-153 signaling induced by hypertriglyceridemia worsens acute pancreatitis and delays tissue repair.

Severe acute pancreatitis (AP) is a life-threatening disease with up to 30% mortality. Therefore, prevention of AP aggravation and promotion of pancreatic regeneration are critical during the course and treatment of AP. Hypertriglyceridemia (HTG) is an established aggravating factor for AP that hinders pancreatic regeneration; however, its exact mechanism remains unclear. Using miRNA sequencing and further verification, we found that miRNA-153 (miR-153) was upregulated in the pancreas of HTG animal models and in the plasma of patients with HTG-AP. Increased miR-153 aggravated HTG-AP and delayed pancreatic repair via targeting TRAF3. Furthermore, miR-153 was transcriptionally suppressed by sterol regulatory element-binding transcription factor 1c (SREBP1c), which was suppressed by lipoprotein lipase malfunction-induced HTG. Overexpressing SREBP1c suppressed miR-153 expression, alleviated the severity of AP, and facilitated tissue regeneration in vivo. Finally, therapeutic administration of insulin also protected against HTG-AP via upregulating SREBP1c. Collectively, our results not only provide evidence that HTG leads to the development of more severe AP and hinders pancreatic regeneration via inducing persistent dysregulation of SREBP1c/miR-153 signaling, but also demonstrate that SREBP1c activators, including insulin, might be used to treat HTG-AP in patients.

Peritumoral ductular reaction can be a prognostic factor for intrahepatic cholangiocarcinoma.

BACKGROUND: Peritumoral ductular reaction (DR) was reported to be related to the prognosis of combined hepatocellular-cholangiocarcinoma and hepatocellular carcinoma. Non-mucin-producing intrahepatic cholangiocarcinoma (ICC) which may be derived from small bile duct cells or liver progenitor cells (LPCs) was known to us. However, whether peritumoral DR is also related to non-mucin-producing ICCs remains to be investigated. METHODS: Forty-seven patients with non-mucin-producing ICC were eventually included in the study and clinicopathological variables were collected. Immunohistochemical analysis and immunofluorescence staining for cytokeratin 19, proliferating cell nuclear antigen, and α-smooth muscle actin were performed in tumor and peritumor liver tissues. RESULTS: A significant correlation existed between peritumoral DR and local inflammation and fibrosis. (r = 0.357, 95% CI, 0.037-0.557; P = 0.008 and r = 0.742, 95% CI, 0.580-0.849; P < 0.001, respectively). Patients with obvious peritumoral DR had high recurrence rate (81.8% vs 56.0%, P = 0.058) and poor overall and disease-free survival time (P = 0.01 and P = 0.03, respectively) comparing with mild peritumoral DR. Compared with the mild peritumoral DR group, the proliferation activity of LPCs/ cholangiocytes was higher in obvious peritumoral DR, which, however, was not statistically significant. (0.43 ± 0.29 vs 0.28 ± 0.31, P = 0.172). Furthermore, the correlation analysis showed that the DR grade was positively related to the portal/septalα-SMA level (r = 0.359, P = 0.001). CONCLUSIONS: Peritumoral DR was associated with local inflammation and fibrosis. Patients with non-mucin-producing ICC having obvious peritumoral DR had a poor prognosis. Peritumoral DR could be a prognostic factor for ICC. However, the mechanism should be further investigated.

Identifying Modifiable Risk Factors for Relapse in Patients With Schizophrenia in China.

BACKGROUND: Preventing relapse of schizophrenic patients is really a challenge. The present study sought to provide more explicit evidence and factors of different grades and weights by a series of step-by-step analysis through χ2 test, logistic regression analysis and decision-tree model. The results of this study may contribute to controlling relapse of schizophrenic patients. METHODS: A total of 1,487 schizophrenia patients were included who were 18-65 years of age and discharged from 10 hospitals in China from January 2009 to August 2009 and from September 2011 to February 2012 with improvements or recovery of treatment effect. We used a questionnaire to collect information about relapse and correlative factors during one year after discharge by medical record collection and telephone interview. The χ2 test and logistic regression analysis were used to identify risk factors and high-risk factors firstly, and then a decision-tree model was used to find predictive factors. RESULTS: The χ2 test found nine risk factors which were associated with relapse. Logistic regression analysis also showed four high-risk factors further (medication adherence, occupational status, ability of daily living, payment method of medical costs). At last, a decision-tree model revealed four predictors of relapse; it showed that medication adherence was the first grade and the most powerful predictor of relapse (relapse rate for adherence vs. nonadherence: 22.9 vs. 55.7%, χ2 = 116.36, p < 0.001). The second grade factor was occupational status (employment vs. unemployment: 19.7 vs. 42.7%, χ2 = 17.72, p < 0.001); the third grade factors were ability of daily living (normal vs. difficult: 28.4 vs. 54.3%, χ2 = 8.61, p = 0.010) and household income (household income ≥ 3000 RMB vs. <3000 RMB: 28.6 vs. 42.4%, χ2 = 6.30, p = 0.036). The overall positive predictive value (PPV) of the logistic regression was 0.740, and the decision-tree model was 0.726. Both models were reliable. CONCLUSIONS: For schizophrenic patients discharged from hospital, who had good medication adherence, more higher household income, be employed and normal ability of daily living, would be less likely to relapse. Decision tree provides a new path for doctors to find the schizophrenic inpatient's relapse risk and give them reasonable treatment suggestions after discharge.

Feasibility and efficacy evaluation of metallic biliary stents eluting gemcitabine and cisplatin for extrahepatic cholangiocarcinoma.

BACKGROUND: Effective endoscopic management is fundamental for the treatment of extrahepatic cholangiocarcinoma (ECC). However, current biliary stents that are widely used in clinical practice showed no antitumor effect. Drug-eluting stents (DESs) may achieve a combination of local chemotherapy and biliary drainage to prolong stent patency and improve prognosis. AIM: To develop novel DESs coated with gemcitabine (GEM) and cisplatin (CIS)-coloaded nanofilms that can maintain the continuous and long-term release of antitumor agents in the bile duct to inhibit tumor growth and reduce systemic toxicity. METHODS: Stents coated with different drug-eluting components were prepared by the mixed electrospinning method, with poly-L-lactide-caprolactone (PLCL) as the drug-loaded nanofiber membrane and GEM and/or CIS as the antitumor agents. Four different DESs were manufactured with four drug-loading ratios (5%, 10%, 15%, and 20%), including bare-loaded (PLCL-0), single-drug-loaded (PLCL-GEM and PLCL-CIS), and dual-drug-loaded (PLCL-GC) stents. The drug release property, antitumor activity, and biocompatibility were evaluated in vitro and in vivo to confirm the feasibility and efficacy of this novel DES for ECC. RESULTS: The in vitro drug release study showed the stable, continuous release of both GEM and CIS, which was sustained for over 30 d without an obvious initial burst, and a higher drug-loaded content induced a lower release rate. The drug-loading ratio of 10% was used for further experiments due to its ideal inhibitory efficiency and relatively low toxicity. All drug-loaded nanofilms effectively inhibited the growth of EGI-1 cells in vitro and the tumor xenografts of nude mice in vivo; in addition, the dual-loaded nanofilm (PLCL-GC) had a significantly better effect than the single-drug-loaded nanofilms (P < 0.05). No significant differences in the serological analysis (P > 0.05) or histopathological changes were observed between the single-loaded and drug-loaded nanofilms after stent placement in the normal porcine biliary tract. CONCLUSION: This novel PLCL-GEM and CIS-eluting stent maintains continuous, stable drug release locally and inhibits tumor growth effectively in vitro and in vivo. It can also be used safely in normal porcine bile ducts. We anticipate that it might be considered an alternative strategy for the palliative therapy of ECC patients.

Restoration of p53 acetylation by HDAC inhibition permits the necrosis/apoptosis switch of pancreatic ainar cell during experimental pancreatitis in mice.

The severity of acute pancreatitis (AP) is greatly attributed to the pancreatic acinar cell (PAC) death response. It has been established that the apoptosis-inducing therapy can protect against experimental pancreatitis and have great clinical therapeutic potential. However, current pharmacologic agents that target apoptosis during AP largely lack specificity. Thus, it remains imperative to reveal the specific mechanisms governing acinar cell death. Death responses of PAC are manifested by the progressive necrosis accompanied by apoptosis silencing during AP in mice. In this study, we found that the transcriptional activity of p53 was impaired and the expressions of its proapoptotic targets Puma and CD95 were significantly decreased, which explains the apoptosis silencing during AP. Furthermore, we found that the functional depression of p53 was resulted from histone deacetylase (HDAC)-mediated deacetylation of p53 C-terminal in PAC during AP. Treatment of the HDAC inhibitor trichostatin-A restored p53 apoptosis pathway, resulted in a necrosis/apoptosis switch and protected mice from cerulein- or l-Arg-induced AP. Our research identified the HDAC-dependent regulation of p53 activity as a critical mechanism underlying acinar cell death response, which represents a specific target for the treatment of AP.

Hematopoietic PBX-interacting protein mediates cartilage degeneration during the pathogenesis of osteoarthritis.

Osteoarthritis (OA) has been recognized as the most common chronic age-related disease. Cartilage degeneration influences OA therapy. Here we report that hematopoietic pre-B cell leukemia transcription factor-interacting protein (HPIP) is essential for OA development. Elevated HPIP levels are found in OA patients. Col2a1-CreERT2/HPIPf/f mice exhibit obvious skeletal abnormalities compared with their HPIPf/f littermates. HPIP deficiency in mice protects against developing OA. Moreover, intra-articular injection of adeno-associated virus carrying HPIP-specific short hairpin RNA in vivo attenuates OA histological signs. Notably, in vitro RNA-sequencing and chromatin immunoprecipitation sequencing profiles identify that HPIP modulates OA cartilage degeneration through transcriptional activation of Wnt target genes. Mechanistically, HPIP promotes the transcription of Wnt targets by interacting with lymphoid enhancer binding factor 1 (LEF1). Furthermore, HPIP potentiates the transcriptional activity of LEF1 and acetylates histone H3 lysine 56 in the promoters of Wnt targets, suggesting that HPIP is an attractive target in OA regulatory network.

miR-409 Inhibits Human Non-Small-Cell Lung Cancer Progression by Directly Targeting SPIN1.

Lung cancers, the leading cause of cancer mortality worldwide, are characterized by a high metastatic potential. Growing evidence reveals that Spindlin 1 (SPIN1) is involved in tumor progression and carcinogenesis. However, the role of SPIN1 in non-small-cell lung cancer (NSCLC) and the molecular mechanisms underlying SPIN1 in human NSCLC remain undetermined. Here we examined the function of SPIN1 in human NSCLC and found that the expression of SPIN1 was closely correlated with the overall survival and poor prognosis of NSCLC patients. Aberrant regulation of microRNAs (miRNAs) has an important role in cancer progression. We revealed that miR-409 inhibits the expression of SPIN1 by binding directly to the 3' UTR of SPIN1 using dual-luciferase reporter assays. Overexpression of miR-409 significantly suppressed cell migration, growth, and proliferation by inhibiting SPIN1 in vitro and in vivo. SPIN1 overexpression in miR-409-transfected NSCLC cells effectively rescued the suppression of cell migration, growth, and proliferation regulated by miR-409. miR-409 regulates the PI3K/AKT (protein kinase B) pathway in NSCLC. Moreover, clinical data showed that NSCLC patients with high levels of miR-409 experienced significantly better survival. miR-409 expression was also negatively associated with SPIN1 expression. Taken together, these findings highlight that the miR-409/SPIN1 axis is a useful pleiotropic regulatory network and could predict the metastatic potential in NSCLC patients early, indicating the possibility that miR-409 and SPIN1 might be attractive prognostic markers for treating NSCLC patients.

Optimization of the first small-molecule relaxin/insulin-like family peptide receptor (RXFP1) agonists: Activation results in an antifibrotic gene expression profile.

A dose responsive quantitative high throughput screen (qHTS) of >350,000 compounds against a human relaxin/insulin-like family peptide receptor (RXFP1) transfected HEK293 cell line identified 2-acetamido-N-phenylbenzamides 1 and 3 with modest agonist activity. An extensive structure-activity study has been undertaken to optimize the potency, efficacy, and physical properties of the series, resulting in the identification of compound 65 (ML-290), which has excellent in vivo PK properties with high levels of systemic exposure. This series, exemplified by 65, has produced first-in-class small-molecule agonists of RXFP1 and is a potent activator of anti-fibrotic genes.

An easy-to-fabricate clearable CuS-superstructure-based multifunctional theranostic platform for efficient imaging guided chemo-photothermal therapy.

Despite drug delivery systems (DDSs) receiving ever-increasing attention, development of a simple, effective, sensitive and clearable drug delivery and multifunctional theranostic nanoplatform for cancer therapy is still highly desirable and remains a challenge. Herein, using a one-step solvothermal method, hollow acanthosphere-like CuS superstructures assembled from ∼10 nm nanoparticles (NPs) were successfully obtained and used as an efficient drug delivery and theranostic platform for photoacoustic (PA) and infrared (IR) thermal imaging-guided cancer combination therapy. The special hollow characteristic of CuS superstructures with mesoporous shells and large cavities grants them high drug loading capacity; they demonstrate near-infrared (NIR)/pH stimuli-sensitive drug release and pronounced synergetic effects of chemo-photothermal therapy both in vitro and in vivo. In particular, our as-fabricated hollow loose CuS superstructures, with easily breakable characteristic, are biodegradable and able to be cleared from the body when their therapy task is completed. This CuS-superstructure-based clearable drug delivery and "all-in-one" cancer theranostic platform might provide possibilities for improving therapeutic efficacy and minimizing adverse effects.

CD133 expression in cancer cells predicts poor prognosis of non-mucin producing intrahepatic cholangiocarcinoma.

BACKGROUND: CD133 is a marker of stem cells as well cancer stem cells. This study investigated the association between CD133 expression in cancer cells and the clinical outcome of non-mucin producing intrahepatic cholangiocarcinoma (ICC). METHODS: Fifty-seven non-mucin producing ICC patients were enrolled in this study. Immunohistochemistry (IHC) and immunofluorescence staining for CD133 as well as other cancer-associated proteins, including cytokeratin 19, TGF-ß1, p-Smad2 and epithelial-mesenchymal transition (EMT) markers S100A4, E-Cadherin and Vimentin were analyzed. RESULTS: IHC staining showed that tumor cells in 52.6% of patients expressed CD133. The CD133+ patients had significantly higher metastasis rate than those without CD133+ tumor cells (36.7% vs. 10.1%, p = 0.03). The CD133+ patients had shorter overall and disease-free survival time as compared to the CD133- patients. Furthermore, 90.9% of CD133+ patients developed cancer recurrence, as compared to 64.3% of CD133- patients (p = 0.02). As compared to CD133- patients, tumor cells in CD133+ patients demonstrated high levels of TGF-ß/p-Smad2 as well as EMT-like alteration, characterized by loss of E-Cadherin and expression of Vimentin and S100A4. CONCLUSIONS: CD133 expression in ICC tumor cells indicates poor prognosis of the disease and might be associated with TGF-ß related EMT alterations.

PCDHGA9 acts as a tumor suppressor to induce tumor cell apoptosis and autophagy and inhibit the EMT process in human gastric cancer.

The results of a cDNA  array revealed that protocadherin gamma subfamily A, 9 (PCDHGA9) was significantly decreased in SGC-7901 gastric cancer (GC) cells compared with GES-1 normal gastric cells and was strongly associated with the Wnt/ß-catenin and transforming growth factor-ß (TGF-ß)/Smad2/3 signaling pathway. As a member of the cadherin family, PCDHGA9 functions in both cell-cell adhesion and nuclear signaling. However, its role in tumorigenicity or metastasis has not been reported. In the present study, we found that PCDHGA9 was decreased in GC tissues compared with corresponding normal mucosae and its expression was correlated with the GC TNM stage, the UICC stage, differentiation, relapse, and metastasis (p < 0.01). Multivariate Cox analysis revealed that PCDHGA9 was an independent prognostic indicator for overall survival (OS) and disease-free survival (DFS) (p < 0.01). The effects of PCDHGA9 on GC tumor growth and metastasis were examined both in vivo and in vitro. PCDHGA9 knockdown promoted GC cell proliferation, migration, and invasion, whereas PCDHGA9 overexpression inhibited GC tumor growth and metastasis but induced apoptosis, autophagy, and G1 cell cycle arrest. Furthermore, PCDHGA9 suppressed epithelial-mesenchymal transition (EMT) induced by TGF-ß, decreased the phosphorylation of Smad2/3, and inhibited the nuclear translocation of pSmad2/3. Our results suggest that PCDHGA9 might interact with ß-catenin to prevent ß-catenin from dissociating in the cytoplasm and translocating to the nucleus. Moreover, PCDHGA9 overexpression restrained cell proliferation and reduced the nuclear ß-catenin, an indicator of Wnt/ß-catenin pathway activation, suggesting that PCDHGA9 negatively regulates Wnt signaling. Together, these data indicate that PCDHGA9 acts as a tumor suppressor with anti-proliferative activity and anti-invasive ability, and the reduction of PCDHGA9 could serve as an independent prognostic biomarker in GC.

Degradable rhenium trioxide nanocubes with high localized surface plasmon resonance absorbance like gold for photothermal theranostics.

The applications of inorganic theranostic agents in clinical trials are generally limited to their innate non-biodegradability and potential long-term biotoxicity. To address this problem, herein via a straightforward and tailored space-confined on-substrate route, we obtained rhenium trioxide (ReO3) nanocubes (NCs) that display a good biocompatibility and biosafety. Importantly, their aqueous dispersion has high localized surface plasmon resonance (LSPR) absorbance in near-infrared (NIR) region different from previous report, which possibly associates with the charge transfer and structural distortion in hydrogen rhenium bronze (HxReO3), as well as ReO3's cubic shape. Such a high LSPR absorbance in the NIR region endows them with photoacoustic (PA)/infrared (IR) thermal imaging, and high photothermal conversion efficiency (∼57.0%) for efficient ablation of cancer cells. Also, ReO3 NCs show X-ray computed tomography (CT) imaging derived from the high-Z element Re. More attractively, those ReO3 NCs, with pH-dependent oxidized degradation behaviors, are revealed to be relatively stable in hypoxic and weakly acidic microenvironment of tumor for imaging and treatment whilst degradable in normal physiological environments of organs to enable effective clearance. In spite of their degradability, ReO3 NCs still possess tumor targeting capabilities. We thus develop a simple but powerful, safe and biodegradable inorganic theranostic platform to achieve PA/CT/IR imaging-guided cancer photothermal therapy (PTT) for improved therapeutic efficacy and decreased toxic side effects.

ML290 is a biased allosteric agonist at the relaxin receptor RXFP1.

Activation of the relaxin receptor RXFP1 has been associated with improved survival in acute heart failure. ML290 is a small molecule RXFP1 agonist with simple structure, long half-life and high stability. Here we demonstrate that ML290 is a biased agonist in human cells expressing RXFP1 with long-term beneficial actions on markers of fibrosis in human cardiac fibroblasts (HCFs). ML290 did not directly compete with orthosteric relaxin binding and did not affect binding kinetics, but did increase binding to RXFP1. In HEK-RXFP1 cells, ML290 stimulated cAMP accumulation and p38MAPK phosphorylation but not cGMP accumulation or ERK1/2 phosphorylation although prior addition of ML290 increased p-ERK1/2 responses to relaxin. In human primary vascular endothelial and smooth muscle cells that endogenously express RXFP1, ML290 increased both cAMP and cGMP accumulation but not p-ERK1/2. In HCFs, ML290 increased cGMP accumulation but did not affect p-ERK1/2 and given chronically activated MMP-2 expression and inhibited TGF-ß1-induced Smad2 and Smad3 phosphorylation. In vascular cells, ML290 was 10x more potent for cGMP accumulation and p-p38MAPK than for cAMP accumulation. ML290 caused strong coupling of RXFP1 to Gαs and GαoB but weak coupling to Gαi3. ML290 exhibited signalling bias at RXFP1 possessing a signalling profile indicative of vasodilator and anti-fibrotic properties.

Development of an Aryloxazole Class of Hepatitis C Virus Inhibitors Targeting the Entry Stage of the Viral Replication Cycle.

Reliance on hepatitis C virus (HCV) replicon systems and protein-based screening assays has led to treatments that target HCV viral replication proteins. The model does not encompass other viral replication cycle steps such as entry, processing, assembly and secretion, or viral host factors. We previously applied a phenotypic high-throughput screening platform based on an infectious HCV system and discovered an aryloxazole-based anti-HCV hit. Structure-activity relationship studies revealed several compounds exhibiting EC50 values below 100 nM. Lead compounds showed inhibition of the HCV pseudoparticle entry, suggesting a different mode of action from existing HCV drugs. Hit 7a and lead 7ii both showed synergistic effects in combination with existing HCV drugs. In vivo pharmacokinetics studies of 7ii showed high liver distribution and long half-life without obvious hepatotoxicity. The lead compounds are promising as preclinical candidates for the treatment of HCV infection and as molecular probes to study HCV pathogenesis.

ML372 blocks SMN ubiquitination and improves spinal muscular atrophy pathology in mice.

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease and one of the leading inherited causes of infant mortality. SMA results from insufficient levels of the survival motor neuron (SMN) protein, and studies in animal models of the disease have shown that increasing SMN protein levels ameliorates the disease phenotype. Our group previously identified and optimized a new series of small molecules, with good potency and toxicity profiles and reasonable pharmacokinetics, that were able to increase SMN protein levels in SMA patient-derived cells. We show here that ML372, a representative of this series, almost doubles the half-life of residual SMN protein expressed from the SMN2 locus by blocking its ubiquitination and subsequent degradation by the proteasome. ML372 increased SMN protein levels in muscle, spinal cord, and brain tissue of SMA mice. Importantly, ML372 treatment improved the righting reflex and extended survival of a severe mouse model of SMA. These results demonstrate that slowing SMN degradation by selectively inhibiting its ubiquitination can improve the motor phenotype and lifespan of SMA model mice.

Structural Insights into the Activation of Human Relaxin Family Peptide Receptor 1 by Small-Molecule Agonists.

The GPCR relaxin family peptide receptor 1 (RXFP1) mediates the action of relaxin peptide hormone, including its tissue remodeling and antifibrotic effects. The peptide has a short half-life in plasma, limiting its therapeutic utility. However, small-molecule agonists of human RXFP1 can overcome this limitation and may provide a useful therapeutic approach, especially for chronic diseases such as heart failure and fibrosis. The first small-molecule agonists of RXFP1 were recently identified from a high-throughput screening, using a homogeneous cell-based cAMP assay. Optimization of the hit compounds resulted in a series of highly potent and RXFP1 selective agonists with low cytotoxicity, and excellent in vitro ADME and pharmacokinetic properties. Here, we undertook extensive site-directed mutagenesis studies in combination with computational modeling analysis to probe the molecular basis of the small-molecule binding to RXFP1. The results showed that the agonists bind to an allosteric site of RXFP1 in a manner that closely interacts with the seventh transmembrane domain (TM7) and the third extracellular loop (ECL3). Several residues were determined to play an important role in the agonist binding and receptor activation, including a hydrophobic region at TM7 consisting of W664, F668, and L670. The G659/T660 motif within ECL3 is crucial to the observed species selectivity of the agonists for RXFP1. The receptor binding and activation effects by the small molecule ML290 were compared with the cognate ligand, relaxin, providing valuable insights on the structural basis and molecular mechanism of receptor activation and selectivity for RXFP1.

Discovery, Optimization, and Characterization of Novel Chlorcyclizine Derivatives for the Treatment of Hepatitis C Virus Infection.

Recently, we reported that chlorcyclizine (CCZ, Rac-2), an over-the-counter antihistamine piperazine drug, possesses in vitro and in vivo activity against hepatitis C virus. Here, we describe structure-activity relationship (SAR) efforts that resulted in the optimization of novel chlorcyclizine derivatives as anti-HCV agents. Several compounds exhibited EC50 values below 10 nM against HCV infection, cytotoxicity selectivity indices above 2000, and showed improved in vivo pharmacokinetic properties. The optimized molecules can serve as lead preclinical candidates for the treatment of hepatitis C virus infection and as probes to study hepatitis C virus pathogenesis and host-virus interaction.

Identification of novel anti-hepatitis C virus agents by a quantitative high throughput screen in a cell-based infection assay.

Hepatitis C virus (HCV) poses a major health threat to the world. The recent development of direct-acting antivirals (DAAs) against HCV has markedly improved the response rate of HCV and reduced the side effects in comparison to the interferon-based therapy. Despite this therapeutic advance, there is still a need to develop new inhibitors that target different stages of the HCV life cycle because of various limitations of the current regimens. In this study, we performed a quantitative high throughput screening of the Molecular Libraries Small Molecule Repository (MLSMR) of ∼350,000 chemicals for novel HCV inhibitors using our previously developed cell-based HCV infection assay. Following confirmation and structural clustering analysis, we narrowed down to 158 compounds from the initial ∼3000 molecules that showed inhibitory activity for further structural and functional analyses. We were able to assign the majority of these compounds to specific stage(s) in the HCV life cycle. Three of them are direct inhibitors of NS3/4A protease. Most of the compounds appear to act on novel targets in HCV life cycle. Four compounds with novel structure and excellent drug-like properties, three targeting HCV entry and one targeting HCV assembly/secretion, were advanced for further development as lead hits. These compounds represent diverse chemotypes that are potential lead compounds for further optimization and may offer promising candidates for the development of novel therapeutics against HCV infection. In addition, they represent novel molecular probes to explore the complex interactions between HCV and the cells.