bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibition of HIV-1 Maturation via Small-Molecule Targeting of the Amino-Terminal Domain in the Viral Capsid Protein
Authors: Wang Weifeng , Zhou Jing , Halambage Upul D. , Jurado Kellie A. , Jamin Augusta V. , Wang Yujie , Engelman Alan N. , Aiken Christopher 
Published: February 2017

ABSTRACT

The human immunodeficiency virus type 1 (HIV-1) capsid protein is an attractive therapeutic target, owing to its multifunctionality in virus replication and the high fitness cost of amino acid substitutions in capsids to HIV-1 infectivity. To date, small-molecule inhibitors have been identified that inhibit HIV-1 capsid assembly and/or impair its function in target cells. Here, we describe the mechanism of action of the previously reported capsid-targeting HIV-1 inhibitor, Boehringer-Ingelheim compound 1 (C1). We show that C1 acts during HIV-1 maturation to prevent assembly of a mature viral capsid. However, unlike the maturation inhibitor bevirimat, C1 did not significantly affect the kinetics or fidelity of Gag processing. HIV-1 particles produced in the presence of C1 contained unstable capsids that lacked associated electron density and exhibited impairments in early postentry stages of infection, most notably reverse transcription. C1 inhibited assembly of recombinant HIV-1 CA
in vitro
and induced aberrant cross-links in mutant HIV-1 particles capable of spontaneous intersubunit disulfide bonds at the interhexamer interface in the capsid lattice. Resistance to C1 was conferred by a single amino acid substitution within the compound-binding site in the N-terminal domain of the CA protein. Our results demonstrate that the binding site for C1 represents a new pharmacological vulnerability in the capsid assembly stage of the HIV-1 life cycle.

IMPORTANCE
The HIV-1 capsid protein is an attractive but unexploited target for clinical drug development. Prior studies have identified HIV-1 capsid-targeting compounds that display different mechanisms of action, which in part reflects the requirement for capsid function at both the efferent and afferent phases of viral replication. Here, we show that one such compound, compound 1, interferes with assembly of the conical viral capsid during virion maturation and results in perturbations at a specific protein-protein interface in the capsid lattice. We also identify and characterize a mutation in the capsid protein that confers resistance to the inhibitor. This study reveals a novel mechanism by which a capsid-targeting small molecule can inhibit HIV-1 replication.
Endogenous Brain Lipids Inhibit Prion Amyloid Formation
In Vitro
Authors: Hoover Clare E. , Davenport Kristen A. , Henderson Davin M. , Zabel Mark D. , Hoover Edward A. 
Published: February 2017

ABSTRACT

The normal cellular prion protein (PrP
C
) resides in detergent-resistant outer membrane lipid rafts in which conversion to the pathogenic misfolded form is believed to occur. Once misfolding occurs, the pathogenic isoform polymerizes into highly stable amyloid fibrils.
In vitro
assays have demonstrated an intimate association between prion conversion and lipids, specifically phosphatidylethanolamine, which is a critical cofactor in the formation of synthetic infectious prions. In the current work, we demonstrate an alternative inhibitory function of lipids in the prion conversion process as assessed
in vitro
by real-time quaking-induced conversion (RT-QuIC). Using an alcohol-based extraction technique, we removed the lipid content from chronic wasting disease (CWD)-infected white-tailed deer brain homogenates and found that lipid extraction enabled RT-QuIC detection of CWD prions in a 2-log
10
-greater concentration of brain sample. Conversely, addition of brain-derived lipid extracts to CWD prion brain or lymph node samples inhibited amyloid formation in a dose-dependent manner. Subsequent lipid analysis demonstrated that this inhibitory function was restricted to the polar lipid fraction in brain. We further investigated three phospholipids commonly found in lipid membranes, phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinositol, and found all three similarly inhibited RT-QuIC. These results demonstrating polar-lipid, and specifically phospholipid, inhibition of prion-seeded amyloid formation highlight the diverse roles lipid constituents may play in the prion conversion process.

IMPORTANCE
Prion conversion is likely influenced by lipid interactions, given the location of normal prion protein (PrP
C
) in lipid rafts and lipid cofactors generating infectious prions in
in vitro
models. Here, we use real-time quaking-induced conversion (RT-QuIC) to demonstrate that endogenous brain polar lipids can inhibit prion-seeded amyloid formation, suggesting that prion conversion is guided by an environment of proconversion and anticonversion lipids. These experiments also highlight the applicability of RT-QuIC to identify potential therapeutic inhibitors of prion conversion.
Glycosylation Benchmark Profile for HIV-1 Envelope Glycoprotein Production Based on Eleven Env Trimers
Authors: Go Eden P. , Ding Haitao , Zhang Shijian , Ringe Rajesh P. , Nicely Nathan , Hua David , Steinbock Robert T. , Golabek Michael , Alin James , Alam S. Munir , Cupo Albert , Haynes Barton F. , Kappes John C. , Moore John P. , Sodroski Joseph G. , Desaire Heather 
Published: February 2017

ABSTRACT
HIV-1 envelope glycoprotein (Env) glycosylation is important because individual glycans are components of multiple broadly neutralizing antibody epitopes, while shielding other sites that might otherwise be immunogenic. The glycosylation on Env is influenced by a variety of factors, including the genotype of the protein, the cell line used for its expression, and the details of the construct design. Here, we used a mass spectrometry (MS)-based approach to map the complete glycosylation profile at every site in multiple HIV-1 Env trimers, accomplishing two goals. (i) We determined which glycosylation sites contain conserved glycan profiles across many trimeric Envs. (ii) We identified the variables that impact Env's glycosylation profile at sites with divergent glycosylation. Over half of the gp120 glycosylation sites on 11 different trimeric Envs have a conserved glycan profile, indicating that a native consensus glycosylation profile does indeed exist among trimers. We showed that some soluble gp120s and gp140s exhibit highly divergent glycosylation profiles compared to trimeric Env. We also assessed the impact of several variables on Env glycosylation: truncating the full-length Env; producing Env, instead of the more virologically relevant T lymphocytes, in CHO cells; and purifying Env with different chromatographic platforms, including nickel-nitrilotriacetic acid (Ni-NTA), 2G12, and PGT151 affinity. This report provides the first consensus glycosylation profile of Env trimers, which should serve as a useful benchmark for HIV-1 vaccine developers. This report also defines the sites where glycosylation may be impacted when Env trimers are truncated or produced in CHO cells.

IMPORTANCE
A protective HIV-1 vaccine will likely include a recombinant version of the viral envelope glycoprotein (Env). Env is highly glycosylated, and yet vaccine developers have lacked guidance on how to assess whether their immunogens have optimal glycosylation. The following important questions are still unanswered. (i) What is the “target” glycosylation profile, when the goal is to generate a natively glycosylated protein? (ii) What variables exert the greatest influence on Env glycosylation? We identified numerous sites on Env where the glycosylation profile does not deviate in 11 different Env trimers, and we investigated the impact on the divergent glycosylation profiles of changing the genotype of the Env sequence, the construct design, the purification method, and the producer cell type. The data presented here give vaccine developers a “glycosylation target” for their immunogens, and they show how protein production variables can impact Env glycosylation.
CanWalk: a feasibility study with embedded randomised controlled trial pilot of a walking intervention for people with recurrent or metastatic cancer
Authors: Tsianakas Vicki , Harris Jenny , Ream Emma , Van Hemelrijck Mieke , Purushotham Arnie , Mucci Lorelei , Green James S A , Fewster Jacquetta , Armes Jo 
Published: February 2017

ObjectivesWalking is an adaptable, inexpensive and accessible form of physical activity. However, its impact on quality of life (QoL) and symptom severity in people with advanced cancer is unknown. This study aimed to assess the feasibility and acceptability of a randomised controlled trial (RCT) of a community-based walking intervention to enhance QoL in people with recurrent/metastatic cancer.DesignWe used a mixed-methods design comprising a 2-centre RCT and nested qualitative interviews.ParticipantsPatients with advanced breast, prostate, gynaecological or haematological cancers randomised 1:1 between intervention and usual care.InterventionThe intervention comprised Macmillan's ‘Move More’ information, a short motivational interview with a recommendation to walk for at least 30 min on alternate days and attend a volunteer-led group walk weekly.OutcomesWe assessed feasibility and acceptability of the interventionandRCT by evaluating study processes (rates of recruitment, consent, retention, adherence and adverse events), and using end-of-study questionnaires and qualitative interviews. Patient-reported outcome measures (PROMs) assessing QoL, activity, fatigue, mood and self-efficacy were completed at baseline and 6, 12 and 24 weeks.ResultsWe recruited 42 (38%) eligible participants. Recruitment was lower than anticipated (goal n=60), the most commonly reported reason being unable to commit to walking groups (n=19). Randomisation procedures worked well with groups evenly matched for age, sex and activity. By week 24, there was a 45% attrition rate. Most PROMs while acceptable were not sensitive to change and did not capture key benefits.ConclusionsThe intervention was acceptable, well tolerated and the study design was judged acceptable and feasible. Results are encouraging and demonstrate that exercise was popular and conveyed benefit to participants. Consequently, an effectiveness RCT is warranted, with some modifications to the intervention to include greater tailoring and more appropriate PROMs selected.Trial registration numberISRCTN42072606.
A Comparison of Two Monofilament Suture Materials for Repair of Partial Flexor Tendon Lacerations: A Controlled In-vitro Study
Authors: Gulihar Abhinav , Whitehead-Clarke Thomas , Hajipour Ladan , Dias Joseph J. 
Published: February 2017

Background: Surgical repair is advocated for flexor tendon lacerations deeper than 70%. Repair can be undertaken with different suturing techniques and using different materials. Different materials used for tendon repair will have a different gliding resistance (GR) at the joint. Previous studies have compared strength of repair and gliding resistance for various braided suture materials and for 100% laceration of flexor tendons. We directly compare the GR of two monofilament sutures when used for a peripheral running suture repair of partially lacerated tendons. Methods: Sixteen flexor tendons and A2 pulleys were harvested from Turkey feet. They were prepared, partially lacerated to 50% depth, and then repaired with a core suture (modified Kessler technique with 4-0 Ethibond) as well as an additional superficial running suture of either 6-0 Prolene or Nylon (half randomised to each). Gliding resistance was measured for all tendons before and after repair, at different flexion angles (40 and 60 degrees) and for different loads (2N and 4N). Results: After surgical repair, gliding resistance was increased for all tendons (P < 0.01). The tendons repaired with Prolene had a higher mean gliding resistance than those repaired with Nylon (P = 0.02). Increased flexion angle and load amplified the gliding resistance (both P < 0.01). Conclusions: 6-0 Nylon was associated with a lower gliding resistance than 6-0 Prolene but the minor differences bare unknown clinical significance.
Valgus Instability of the Elbow Due to Medial Epicondyle Nonunion: Treatment by Fragment Excision and Medial Collateral Ligament Reconstruction
Authors: Kaneshiro Yasunori , Hidaka Noriaki , Yano Koichi , Fukuda Makoto , Sakanaka Hideki 
Published: February 2017

Background: The medial epicondyle nonunion becomes symptomatic valgus instability with medial elbow pain and joint instability due to dysfunction of the medial collateral ligament (MCL), thus requiring surgical treatment. The purpose of the present study is to report the clinical result of the fragment excision and ligament reconstruction by free tendon graft in the treatment of symptomatic medial epicondyle nonunion. Methods: A retrospective study of five consecutive patients was performed. All five patients had signs and symptoms of valgus instability of the elbow. The mean period of nonunion was 25 years, and their injuries progressed asymptomatically until symptoms developed in adulthood after a second injury. Results: All patients were treated by fragment excision and MCL reconstruction. At the final follow-up, no patients exhibited pain or instability. The mean joint range of motion was 0o of extension and 138o of flexion, with an MEPS of 100 points in all patients. Conclusions: By ligament reconstruction for MCL insufficiency and removing the bone fragments avoided irritation by the bone fragments, pain and instability disappeared, good range of motion was restored, and excellent outcomes were achieved in all patients. We believe that fragment excision and MCL reconstruction should be considered as the treatment option for symptomatic medial epicondyle nonunion of the humerus.
Asymptomatic Flexor Tendon Damages after Volar Locking Plate Fixation of Distal Radius Fractures
Authors: Tokunaga Susumu , Abe Yoshihiro 
Published: February 2017

Background: To investigate asymptomatic flexor tendon damages after volar locking plate fixation of distal radius fractures in 32 wrists of 32 patients with distal radius fractures fixed using two plate types. Sixteen patients received the Acu-Loc volar distal radius plate, and the remaining 16 patients received the Aptus distal radius correction plate.Methods: The flexor pollicis longus (FPL) tendon and flexor digitorum profundus were evaluated according to intraoperative findings at plate removal. Ultrasonography was used to measure the distance between the FPL tendon and distal edge of the plates (FPL plate distance) before plate removal, the distance between the FPL tendon and distal edge of the radius (FPL radius distance) after plate removal, in the contralateral wrist, and the angle between an extension line of a volar surface line on the proximal FPL tendon and a second volar surface line on the distal FPL tendon (FPL angles).Results: Erosion of the FPL tendon was identified in four wrists, and erosion of the flexor digitorum profundus of the index finger was identified in one wrist. All five cases of wrists with flexor tendon damage had Acu-Loc plates installed. The average FPL angle before plate removal was 15.4° in the wrists with tendon damage, which was statistically significantly larger than the average FPL angle in the wrists without erosion.Conclusions: The type of plate and larger FPL angle on ultrasonography may be the risk factors for flexor tendon damage.
Differential effect of brief electrical stimulation on voltage-gated potassium channels
Authors: Cameron Morven A. , Al Abed Amr , Buskila Yossi , Dokos Socrates , Lovell Nigel H. , Morley John W. 
Published: February 2017

Electrical stimulation of neuronal tissue is a promising strategy to treat a variety of neurological disorders. The mechanism of neuronal activation by external electrical stimulation is governed by voltage-gated ion channels. This stimulus, typically brief in nature, leads to membrane potential depolarization, which increases ion flow across the membrane by increasing the open probability of these voltage-gated channels. In spiking neurons, it is activation of voltage-gated sodium channels (NaVchannels) that leads to action potential generation. However, several other types of voltage-gated channels are expressed that also respond to electrical stimulation. In this study, we examine the response of voltage-gated potassium channels (KVchannels) to brief electrical stimulation by whole cell patch-clamp electrophysiology and computational modeling. We show that nonspiking amacrine neurons of the retina exhibit a large variety of responses to stimulation, driven by different KV-channel subtypes. Computational modeling reveals substantial differences in the response of specific KV-channel subtypes that is dependent on channel kinetics. This suggests that the expression levels of different KV-channel subtypes in retinal neurons are a crucial predictor of the response that can be obtained. These data expand our knowledge of the mechanisms of neuronal activation and suggest that KV-channel expression is an important determinant of the sensitivity of neurons to electrical stimulation.NEW & NOTEWORTHY This paper describes the response of various voltage-gated potassium channels (KVchannels) to brief electrical stimulation, such as is applied during prosthetic electrical stimulation. We show that the pattern of response greatly varies between KVchannel subtypes depending on activation and inactivation kinetics of each channel. Our data suggest that problems encountered when artificially stimulating neurons such as cessation in firing at high frequencies, or “fading,” may be attributed to KV-channel activation.
Radiation Resistance in KRAS-Mutated Lung Cancer Is Enabled by Stem-like Properties Mediated by an Osteopontin–EGFR Pathway
Authors: Wang Meng , Han Jing , Marcar Lynnette , Black Josh , Liu Qi , Li Xiangyong , Nagulapalli Kshithija , Sequist Lecia V. , Mak Raymond H. , Benes Cyril H. , Hong Theodore S. , Gurtner Kristin , Krause Mechthild , Baumann Michael , Kang Jing X. , Whetstine Johnathan R. , Willers Henning 
Published: February 2017

Abstract
Lung cancers with activating KRAS mutations are characterized by treatment resistance and poor prognosis. In particular, the basis for their resistance to radiation therapy is poorly understood. Here, we describe a radiation resistance phenotype conferred by a stem-like subpopulation characterized by mitosis-like condensed chromatin (MLCC), high CD133 expression, invasive potential, and tumor-initiating properties. Mechanistic investigations defined a pathway involving osteopontin and the EGFR in promoting this phenotype. Osteopontin/EGFR–dependent MLCC protected cells against radiation-induced DNA double-strand breaks and repressed putative negative regulators of stem-like properties, such as CRMP1 and BIM. The MLCC-positive phenotype defined a subset of KRAS-mutated lung cancers that were enriched for co-occurring genomic alterations in TP53 and CDKN2A. Our results illuminate the basis for the radiation resistance of KRAS-mutated lung cancers, with possible implications for prognostic and therapeutic strategies. Cancer Res; 77(8); 2018–28. ©2017 AACR.
Role of Megakaryocytes in Breast Cancer Metastasis to Bone
Authors: Jackson Walter , Sosnoski Donna M. , Ohanessian Sara E. , Chandler Paige , Mobley Adam , Meisel Kacey D. , Mastro Andrea M. 
Published: February 2017

Abstract
Little is known about how megakaryocytes may affect metastasis beyond serving as a source of platelets. In this study, we explored the functional implications of megakaryocyte accumulation in the femurs of mice after injection of metastatic or non-metastatic breast cancer cells in 4T1.2 BALB/cJ and MDA-MB-231 nude mouse models. At bone metastatic sites, but not primary growth sites, tumor growth was associated with increased megakaryopoiesis in both model systems. In the orthotopic BALB/cJ model, extramedullary hematopoiesis occurred in the spleen, resulting in a four-fold increase in megakaryocytes. In support of the hypothesis that reducing megakaryocytes may reduce metastasis, we found that thrombopoietin-deficient mice exhibited a 90% relative decrease in megakaryocytes, yet they developed more aggressive metastasis than wild-type hosts. In human clinical specimens, we observed an increase in megakaryocytes in the bone marrow of 6/8 patients with metastatic breast cancer compared with age- and gender-matched controls. Taken together, our results suggested that an increase in megakaryocytes occurring in response to metastatic cells entering the bone marrow confers some measure of protection against metastasis, challenging present views on the role of megakaryocytes in this setting. Cancer Res; 77(8); 1942–54. ©2017 AACR.
Ex Vivo Explant Cultures of Non–Small Cell Lung Carcinoma Enable Evaluation of Primary Tumor Responses to Anticancer Therapy
Authors: Karekla Ellie , Liao Wen-Jing , Sharp Barry , Pugh John , Reid Helen , Quesne John Le , Moore David , Pritchard Catrin , MacFarlane Marion , Pringle James Howard 
Published: February 2017

Abstract
To improve treatment outcomes in non–small cell lung cancer (NSCLC), preclinical models that can better predict individual patient response to novel therapies are urgently needed. Using freshly resected tumor tissue, we describe an optimized ex vivo explant culture model that enables concurrent evaluation of NSCLC response to therapy while maintaining the tumor microenvironment. We found that approximately 70% of primary NSCLC specimens were amenable to explant culture with tissue integrity intact for up to 72 hours. Variations in cisplatin sensitivity were noted with approximately 50% of cases responding ex vivo. Notably, explant responses to cisplatin correlated significantly with patient survival (P = 0.006) irrespective of tumor stage. In explant tissue, cisplatin-resistant tumors excluded platinum ions from tumor areas in contrast to cisplatin-sensitive tumors. Intact TP53 did not predict cisplatin sensitivity, but a positive correlation was observed between cisplatin sensitivity and TP53 mutation status (P = 0.003). Treatment of NSCLC explants with the targeted agent TRAIL revealed differential sensitivity with the majority of tumors resistant to single-agent or cisplatin combination therapy. Overall, our results validated a rapid, reproducible, and low-cost platform for assessing drug responses in patient tumors ex vivo, thereby enabling preclinical testing of novel drugs and helping stratify patients using biomarker evaluation. Cancer Res; 77(8); 2029–39. ©2017 AACR.