The microRNA miR-148a functions as a critical regulator of B cell tolerance and autoimmunity.

Autoreactive B cells have critical roles in a large diversity of autoimmune diseases, but the molecular pathways that control these cells remain poorly understood. We performed an in vivo functional screen of a lymphocyte-expressed microRNA library and identified miR-148a as a potent regulator of B cell tolerance. Elevated miR-148a expression impaired B cell tolerance by promoting the survival of immature B cells after engagement of the B cell antigen receptor by suppressing the expression of the autoimmune suppressor Gadd45α, the tumor suppressor PTEN and the pro-apoptotic protein Bim. Furthermore, increased expression of miR-148a, which occurs frequently in patients with lupus and lupus-prone mice, facilitated the development of lethal autoimmune disease in a mouse model of lupus. Our studies demonstrate a function for miR-148a as a regulator of B cell tolerance and autoimmunity.

Significant Association of Candidate Genes (AGTR1 and TGF-Β1) Polymorphism with Diabetic Nephropathy in Diabetes Mellitus Type 2 Patients.

BACKGROUND/AIMS: Diabetic nephropathy (DN) is one of the complications of diabetes mellitus (DM). This study aimed to investigate the association between genetic polymorphisms, specifically AGTR1 (rs5186) and TGF-ß1 (rs1800470), and the risk of developing Diabetic nephropathy (DN) in type 2 diabetes mellitus patients, compared to those without DN and healthy controls. METHODS: A case-control study was conducted on 165 diabetic patients (59 with diabetic nephropathy (DN) and 54 without DN (DM)), and 52 healthy controls (HC). The genotyping was done using amplification refractory mutation system method (ARMS-PCR). Age, gender, and duration of diabetes were matched across groups. Clinical parameters including FBS, RBS, HbA1C, creatinine, urea, SBP, DBP, total cholesterol, triglycerides, LDL, and BMI were assessed. RESULTS: Diabetic patients with nephropathy exhibited significantly higher levels of clinical parameters compared to those without nephropathy and healthy controls. The risk allele of AGTR1 , C (p <0.0001), and risk allele containing genotypes AC (p <0.0001) and CC (p - 0.0010) were significantly higher in DN patients compared to DM and HC groups. Similarly, the TGF-ß1 risk allele C (p - 0.0001), and corresponding genotypes TC (p - 0.0038) and CC (p - 0.0027) were significantly associated with increased risk of diabetic nephropathy compared to DM and HC groups. CONCLUSION: The data showed significant association of AGTR1 (rs5186) and TGF-ß1 (rs1800470) polymorphism with an increased risk of diabetic nephropathy in type 2 diabetes mellitus patients. More investigation will be required to disseminate the results, while increasing the samples size and using whole genome sequencing.

BRAF and RET polymorphism association with thyroid cancer risk, a preliminary study from Khyber Pakhtunkhwa population.

BACKGROUND: Thyroid cancer, originating in the neck's thyroid gland, encompasses various types. Genetic mutations, particularly in BRAF and RET genes are crucial in its development. This study investigates the association between BRAF (rs113488022) and RET (rs77709286) polymorphisms and thyroid cancer risk in the Khyber Pakhtunkhwa (KP) population. METHODS: Blood samples from 100 thyroid cancer patients and 100 healthy controls were genotyped using ARMS-PCR followed by gel electrophoresis and statistical analysis. RESULTS: Analysis revealed a significant association between the minor allele T of BRAF (rs113488022) and thyroid cancer risk (P = 0.0001). Both genotypes of BRAF (rs113488022) showed significant associations with thyroid cancer risk (AT; P = 0.0012 and TT; P = 0.045). Conversely, the minor allele G of RET (rs77709286) exhibited a non-significant association with thyroid cancer risk (P = 0.2614), and neither genotype showed significant associations (CG; P = 0.317, GG; P = 0.651). Demographic and clinical parameters analysis using SPSS showed a non-significant association between BRAF and RET variants and age group (P = 0.878 and P = 0.536), gender (P = 0.587 and P = 0.21), tumor size (P = 0.796 and P = 0.765), or tumor localization (P = 0.689 and P = 0.727). CONCLUSION: In conclusion, this study emphasizes the significant association between BRAF polymorphism and thyroid cancer risk, while RET polymorphism showed a less pronounced impact. Further validation using larger and specific datasets is essential to establish conclusive results.

Significant association of BRCA1 (rs1799950), BRCA2 (rs144848) and TP53 (rs1042522) polymorphism with breast cancer risk in Pashtun population of Khyber Pakhtunkhwa, Pakistan.

BACKGROUND: Single nucleotide polymorphism (SNPs) in BRCA1, BRCA2 and TP53 has been widely associated with breast cancer risk in different ethnicities with inconsistent results. There is no such study conducted so far in the Pashtun population of Khyber Pakhtunkhwa, Pakistan. Therefore, this study was conducted to check BRCA1 (rs1799950), BRCA2 (rs144848) and TP53 (rs1042522) polymorphism with breast cancer risk in Pashtun population of Khyber Pakhtunkhwa, Pakistan. METHODS: This study, consisting 140 breast cancer patients and 80 gender and age matched healthy controls were subjected to confirm BRCA1, BRCA2 and TP53 polymorphism. Clinicopathological data and blood samples were taken from all the participants. DNA was extracted and SNPs were confirmed using T-ARMS-PCR protocol. RESULTS: Our data indicated that BRCA1, BRCA2, and TP53 selected SNPs risk allele and risk allele containing genotypes displayed significant association (p < 0.05) with breast cancer risk in the Pashtun population of Khyber Pakhtunkhwa, Pakistan. CONCLUSION: All the three selected SNPs of BRCA1, BRCA2 and TP53 showed significant association with breast cancer risk in the Pashtun population of Khyber Pakhtunkhwa, Pakistan. However, more investigation will be required on large data sets to confirm the selected SNPs and other SNPs in the selected and other related genes with the risk of breast cancer.

Human nuclear RNAi-defective 2 (NRDE2) is an essential RNA splicing factor.

The accurate inheritance of genetic material is a basic necessity in all domains of life and an unexpectedly large number of RNA processing factors are required for mitotic progression and genome stability. NRDE2 (nuclear RNAi defective-2) is an evolutionarily conserved protein originally discovered for its role in nuclear RNA interference (RNAi) and heritable gene silencing in Caenorhabditis elegans (C. elegans). The function of the human NRDE2 gene remains poorly understood. Here we show that human NRDE2 is an essential protein required for suppressing intron retention in a subset of pre-mRNAs containing short, GC-rich introns with relatively weak 5' and 3' splice sites. NRDE2 preferentially interacts with components of the U5 small nuclear ribonucleoprotein (snRNP), the exon junction complex, and the RNA exosome. Interestingly, NRDE2-depleted cells exhibit greatly increased levels of genomic instability and DNA damage, as well as defects in centrosome maturation and mitotic progression. We identify the essential centriolar satellite protein, CEP131, as a direct NRDE2-regulated target. NRDE2 specifically binds to and promotes the efficient splicing of CEP131 pre-mRNA, and depleting NRDE2 dramatically reduces CEP131 protein expression, contributing to impaired recruitment of critical centrosomal proteins (e.g., γ-tubulin and Aurora Kinase A) to the spindle poles during mitosis. Our work establishes a conserved role for human NRDE2 in RNA splicing, characterizes the severe genomic instability phenotypes observed upon loss of NRDE2, and highlights the direct regulation of CEP131 splicing as one of multiple mechanisms through which such phenotypes might be explained.

Reliability of the Dorsal Tangential View in Assessment of Distal Radioulnar Joint Reduction in the Neutral, Pronated, and Supinated Positions in a Cadaver Model.

PURPOSE: Intraoperative assessment of distal radioulnar joint (DRUJ) alignment is often based on lateral radiographs whose interpretation is dependent upon positioning the forearm in neutral rotation. The dorsal tangential view (DTV) is a near-axial view of the dorsal wrist used in assessing dorsal screw penetration during radius fixation. The purpose of this study was to determine whether the DTV can also reliably assess DRUJ alignment in multiple forearm positions. METHODS: Four transhumeral cadaveric specimens were used to simulate an unstable DRUJ. The stabilizing soft tissue structures of the DRUJ were sectioned. Fluoroscopic DTV images were obtained with the DRUJ of each specimen held in 5 positions: dorsally dislocated, dorsally subluxated, reduced, volarly subluxated, and volarly dislocated. In each position, images were taken with the forearm in neutral rotation, full pronation, and full supination. Three observers independently assessed DRUJ position on DTV images. Intra- and interobserver reliability were assessed in each forearm position. RESULTS: Observers correctly identified DRUJ position as reduced, volarly malreduced, or dorsally malreduced on 94% of the DTV images (97%, 95%, and 92% in the neutral, supinated, and pronated forearm positions, respectively). Weighted kappa values for intraobserver reliability were 0.965, 0.964, and 0.965 for the 3 observers. The mean kappas for intraobserver reliability were 1.000, 0.967, and 0.930 with the forearm in neutral, supinated, and pronated positions, respectively. Weighted kappa values for interobserver reliability between paired observers were 0.948, 0.912, and 0.929. The mean kappa for interobserver reliability was 0.926, 0.931, and 0.930 for the forearm in neutral, supinated, and pronated positions, respectively. CONCLUSIONS: The DTV reliably demonstrated the position of the DRUJ independent of forearm rotation in a cadaveric model. CLINICAL RELEVANCE: Surgeons may consider the DTV as another tool for fluoroscopic verification of the DRUJ reduction in the operating room or clinic.

Prdm1 Regulates Thymic Epithelial Function To Prevent Autoimmunity.

Autoimmunity is largely prevented by medullary thymic epithelial cells (TECs) through their expression and presentation of tissue-specific Ags to developing thymocytes, resulting in deletion of self-reactive T cells and supporting regulatory T cell development. The transcription factor Prdm1 has been implicated in autoimmune diseases in humans through genome-wide association studies and in mice using cell type-specific deletion of Prdm1 in T and dendritic cells. In this article, we demonstrate that Prdm1 functions in TECs to prevent autoimmunity in mice. Prdm1 is expressed by a subset of mouse TECs, and conditional deletion of Prdm1 in either Keratin 14- or Foxn1-expressing cells in mice resulted in multisymptom autoimmune pathology. Notably, the development of Foxp3+ regulatory T cells occurs normally in the absence of Blimp1. Importantly, nude mice developed anti-nuclear Abs when transplanted with Prdm1 null TECs, but not wild-type TECs, indicating that Prdm1 functions in TECs to regulate autoantibody production. We show that Prdm1 acts independently of Aire, a crucial transcription factor implicated in medullary TEC function. Collectively, our data highlight a previously unrecognized role for Prdm1 in regulating thymic epithelial function.

Exercise and weight loss interventions and miRNA expression in women with breast cancer.

PURPOSE: Obesity and weight gain are associated with comorbidities including a higher risk of tumor recurrence and cancer-related deaths among breast cancer (BC) survivors; however, the underlying mechanisms linking obesity and cancer are poorly understood. Given the lack of clinically validated BC biomarkers, obesity and weight-loss studies utilize serum biomarkers as the intermediary outcomes of tumor recurrence. Studies have indicated microRNAs (miRNA)s are reliable biomarkers for cancer. We hypothesized that miRNA expression correlates with obesity and weight loss amongst BC survivors. This would yield insight into the biological pathways by which this association occurs, enabling more precise development of therapeutics. PATIENTS AND METHODS: We correlated baseline body mass index (BMI) with serum miRNA expression in 121 BC survivors enrolled in the Hormones and Physical Exercise (HOPE) trial. We then analyzed expression of the 35 most abundant miRNAs from HOPE in a six-month randomized controlled weight-loss trial (Lifestyle, Exercise, and Nutrition; LEAN) in 100 BC survivors. Ingenuity pathway analysis (IPA) software was used to identify biological pathway targets of the BMI-associated and intervention-responsive miRNAs using predictive biomarkers. RESULTS: Pearson correlations in HOPE identified eight miRNAs associated with BMI, including miR-191-5p (r = - 0.22, p = 0.016) and miR-122-5p (r = 0.25, p = 0.0048). In the LEAN validation study, levels of miR-191-5p significantly increased during the six-month intervention (p = 0.082). Ingenuity Pathway Analysis identified "Estrogen-mediated S-phase entry" (HOPE p = 0.003; LEAN p < 0.001) and "Molecular mechanisms of cancer" (HOPE p = 0.02; LEAN p < 0.001) as the top canonical pathways that significantly correlated with BMI-associated and intervention-responsive miRNAs and contain obesity and cancer-relevant genes including the E2F family of transcription factors and CCND1, which have been implicated in sporadic BC. CONCLUSION: While the association between obesity and BC recurrence and mortality has been demonstrated in the literature, mechanisms underlying the link between weight gain and cancer are unclear. Using two independent clinical trials, we identified novel miRNAs associative to BMI and weight loss that contribute to the development of cancer. Predictive modeling of miRNA targets identified multiple canonical pathways associated with cancer, highlighting potential mechanisms explaining the link between BMI and increased cancer risk.

Wrist Arthrodesis for Failed Total Wrist Arthroplasty.

PURPOSE: Treatment options for failed total wrist arthroplasty include implant revision, resection arthroplasty, and arthrodesis. Variable results associated with different techniques have been reported for arthrodesis and the procedure has substantial technical challenges, including restoration of wrist height, obtaining stable fixation, and achieving bony fusion. This study evaluates the radiographic results of a surgical technique for conversion of a failed arthroplasty to an arthrodesis. METHODS: A retrospective chart and radiograph review was performed in 20 wrists in 18 patients in whom conversion to an arthrodesis was performed using a contoured cancellous femoral head structural allograft and a wrist arthrodesis plate. Supplemental demineralized bone matrix combined with corticocancellous allograft chips was also used in 15 wrists. Median age at arthrodesis was 61 years (range, 45-78 years), and median follow-up was 34 months (range, 4-71 months). RESULTS: Nineteen of 20 wrists fused following the index procedure at a median of 4 months (range, 3-7 months). Proximal plate loosening occurred in 1 wrist but the joint still fused at 6 months; a successful osteotomy and revision of screw fixation was done 2 years later to correct the deformity and hardware irritation in this case. Complications were otherwise limited to 1 superficial infection that resolved with intravenous antibiotics. CONCLUSIONS: This technique for conversion of a failed total wrist arthroplasty to a wrist arthrodesis is safe, effective, and versatile. Wrist deformity is corrected, wrist height can be restored, stable fixation is obtained, and a high rate of fusion is achieved despite filling large defects using structural cancellous allograft. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Closed Sagittal Band Injury of the Metacarpophalangeal Joint.

Although it is an uncommon injury, traumatic rupture of the sagittal band often results in subluxation or dislocation of the extensor digitorum communis tendon. The radial sagittal band prevents ulnar subluxation of the extensor tendon at the metacarpophalangeal joint. Injury may result from a direct blow to the hand or from relatively low-energy mechanisms. Symptoms range from metacarpophalangeal joint pain and edema to dislocation of the extensor tendon. Associated injuries include collateral ligament sprains, capsular injury, and osteochondral fractures. Many acute injuries can be managed nonsurgically with extension splints. Optimal management of subacute or chronic injuries remains undefined. Surgical management consists of repair or reconstruction of the radial sagittal band. Numerous adjunctive surgical techniques have been described to prevent subluxation of the extensor tendon.

Nature of Li2O2 oxidation in a Li-O2 battery revealed by operando X-ray diffraction.

Fundamental research into the Li-O2 battery system has gone into high gear, gaining momentum because of its very high theoretical specific energy. Much progress has been made toward understanding the discharge mechanism, but the mechanism of the oxygen evolution reaction (OER) on charge (i.e., oxidation) remains less understood. Here, using operando X-ray diffraction, we show that oxidation of electrochemically generated Li2O2 occurs in two stages, but in one step for bulk crystalline (commercial) Li2O2, revealing a fundamental difference in the OER process depending on the nature of the peroxide. For electrochemically generated Li2O2, oxidation proceeds first through a noncrystalline lithium peroxide component, followed at higher potential by the crystalline peroxide via a Li deficient solid solution (Li(2-x)O2) phase. Anisotropic broadening of the X-ray Li2O2 reflections confirms a platelet crystallite shape. On the basis of the evolution of the broadening during charge, we speculate that the toroid particles are deconstructed one platelet at a time, starting with the smallest sizes that expose more peroxide surface. In the case of in situ charged bulk crystalline Li2O2, the Li vacancies preferentially form on the interlayer position (Li1), which is supported by first-principle calculations and consistent with their lower energy compared to those located next to oxygen (Li2). The small actively oxidizing fraction results in a gradual reduction of the Li2O2 crystallites. The fundamental insight gained in the OER charge mechanism and its relation to the nature of the Li2O2 particles is essential for the design of future electrodes with lower overpotentials, one of the key challenges for high performance Li-air batteries.

Risk factors for 30-day postoperative complications and mortality following open reduction internal fixation of distal radius fractures.

PURPOSE: To identify the incidence and risk factors for 30-day postoperative morbidity and mortality following operative treatment of distal radius fractures in a multicenter cohort. METHODS: We retrospectively queried the American College of Surgeons National Surgical Quality Improvement Program database for the years 2005-2011 for cases of closed distal radius fractures treated operatively with internal fixation. Patient demographics, comorbidities, and operative characteristics were analyzed. Thirty-day postoperative complications were identified and separated into categories of major morbidity or mortality, minor morbidity, and any complication. Risk factors were identified using univariate and multivariate analyses. RESULTS: We identified 1,673 cases of closed distal radius fractures managed with internal fixation. The overall incidence of having any early complication was 3%. Major morbidity was 2.1%, which included 4 patient deaths, and minor morbidity was 1%. The most common major morbidity was a return to the operating room (16 patients). The most common minor morbidity was urinary tract infection (6 patients). The multivariate analysis demonstrated ASA class III or IV, dependent functional status, hypertension, and myocardial infarction/congestive heart failure to be significant risk factors for any early complication. There was a 10.0% complication rate in the inpatient group and a 1.3% complication rate in the outpatient group. CONCLUSIONS: The incidence of early complications following internal fixation for closed distal radius fractures was low, especially in the outpatient group. In the setting of an isolated injury to the distal radius, the data presented here can provide prognostic information for patients during informed consent for what is considered to be an elective procedure. Surgeons should consider risk of morbidity and mortality when considering surgery for patients with noteworthy cardiopulmonary disease, increased ASA class, or poor functional status. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.

Antigen-specific, antibody-coated, exosome-like nanovesicles deliver suppressor T-cell microRNA-150 to effector T cells to inhibit contact sensitivity.

BACKGROUND: T-cell tolerance of allergic cutaneous contact sensitivity (CS) induced in mice by high doses of reactive hapten is mediated by suppressor cells that release antigen-specific suppressive nanovesicles. OBJECTIVE: We sought to determine the mechanism or mechanisms of immune suppression mediated by the nanovesicles. METHODS: T-cell tolerance was induced by means of intravenous injection of hapten conjugated to self-antigens of syngeneic erythrocytes and subsequent contact immunization with the same hapten. Lymph node and spleen cells from tolerized or control donors were harvested and cultured to produce a supernatant containing suppressive nanovesicles that were isolated from the tolerized mice for testing in active and adoptive cell-transfer models of CS. RESULTS: Tolerance was shown due to exosome-like nanovesicles in the supernatants of CD8(+) suppressor T cells that were not regulatory T cells. Antigen specificity of the suppressive nanovesicles was conferred by a surface coat of antibody light chains or possibly whole antibody, allowing targeted delivery of selected inhibitory microRNA (miRNA)-150 to CS effector T cells. Nanovesicles also inhibited CS in actively sensitized mice after systemic injection at the peak of the responses. The role of antibody and miRNA-150 was established by tolerizing either panimmunoglobulin-deficient JH(-/-) or miRNA-150(-/-) mice that produced nonsuppressive nanovesicles. These nanovesicles could be made suppressive by adding antigen-specific antibody light chains or miRNA-150, respectively. CONCLUSIONS: This is the first example of T-cell regulation through systemic transit of exosome-like nanovesicles delivering a chosen inhibitory miRNA to target effector T cells in an antigen-specific manner by a surface coating of antibody light chains.

Non-coding RNAs and neuroinflammation: implications for neurological disorders.

Neuroinflammation is considered a balanced inflammatory response important in the intrinsic repair process after injury or infection. Under chronic states of disease, injury, or infection, persistent neuroinflammation results in a heightened presence of cytokines, chemokines, and reactive oxygen species that result in tissue damage. In the CNS, the surrounding microglia normally contain macrophages and other innate immune cells that perform active immune surveillance. The resulting cytokines produced by these macrophages affect the growth, development, and responsiveness of the microglia present in both white and gray matter regions of the CNS. Controlling the levels of these cytokines ultimately improves neurocognitive function and results in the repair of lesions associated with neurologic disease. MicroRNAs (miRNAs) are master regulators of the genome and subsequently control the activity of inflammatory responses crucial in sustaining a robust and acute immunological response towards an acute infection while dampening pathways that result in heightened levels of cytokines and chemokines associated with chronic neuroinflammation. Numerous reports have directly implicated miRNAs in controlling the abundance and activity of interleukins, TGF-B, NF-kB, and toll-like receptor-signaling intrinsically linked with the development of neurological disorders such as Parkinson's, ALS, epilepsy, Alzheimer's, and neuromuscular degeneration. This review is focused on discussing the role miRNAs play in regulating or initiating these chronic neurological states, many of which maintain the level and/or activity of neuron-specific secondary messengers. Dysregulated miRNAs present in the microglia, astrocytes, oligodendrocytes, and epididymal cells, contribute to an overall glial-specific inflammatory niche that impacts the activity of neuronal conductivity, signaling action potentials, neurotransmitter robustness, neuron-neuron specific communication, and neuron-muscular connections. Understanding which miRNAs regulate microglial activation is a crucial step forward in developing non-coding RNA-based therapeutics to treat and potentially correct the behavioral and cognitive deficits typically found in patients suffering from chronic neuroinflammation.

Postoperative analysis of patients who received the Universal 2 total wrist implant system.

Third-generation total wrist arthroplasty devices have provided joint stability, relief from pain and increased wrist motion for patients suffering from severe arthritis. While reports of clinical follow-up appointments describe improved wrist function, the improvement in overall upper extremity function and patient perception remains a question. Therefore, the purpose of this study was to assess the upper extremity function in patients that received the Universal 2 total implant system. Eight patients participated in the complete protocol, which included testing activities of daily living as well as surveys to assess patient perception. The findings of the current study suggest that although patients exhibit motion that exceeds the needed amount, many still have a perceived disability.

The Effect of Locking Screws on Distal Component Fixation in Total Wrist Arthroplasty Using a Cadaver Model.

Purpose: The advent of total wrist arthroplasty has allowed for motion-sparing surgical treatment for wrist arthritis. The Integra Freedom Total Wrist Arthroplasty recently incorporated locking caps into its distal component fixation to minimize implant micromotion and improve osseous integration. The purpose of this study was to assess the kinematic effect of locking caps in a cadaveric model. Methods: The Integra Freedom was implanted in 4 matched-pair cadavers and tested with and without the use of the locking caps, with the testing order randomized. Each specimen was tested on a custom testing system in a position of 15° of radial deviation, neutral position, and 15° of ulnar deviation with 25 N, 50 N, 75 N, and 100 N of compressive force. The rotation of the capitate, trapezoid, and hamate at all positions was measured using a 3-dimensional digitizer. Results: Statistical analysis showed no difference in carpal rotation between the nonlocking cap and locking cap groups at all testing loads and wrist positions. The absolute motion of the distal row was minimal. However, of the total 216 loads/positions tested, only 4 (1.8%) showed a rotation of greater than 2° and only 34 (15.7%) showed a rotation of greater than 1°. Conclusions: This study shows that in a time zero cadaveric model, the initial osseous fixation of the distal component in the Integra Freedom is robust with or without locking caps. The addition of locking caps did not have a kinematic effect on distal carpal row fixation. However, further investigation into its clinical role is necessary. Clinical Relevance: At time zero, there is minimal carpal motion after implantation of the Integra Freedom Total Wrist with functional loading. The addition of locking caps did not lead to any decrease in carpal motion.

Reaction mechanisms for electrolytic manganese dioxide in rechargeable aqueous zinc-ion batteries.

This study reports the phase transformation behaviour associated with electrolytic manganese dioxide (EMD) utilized as the positive electrode active material for aqueous zinc-ion batteries. Electrochemical techniques, including galvanostatic charge-discharge and rotating ring-disk electrode measurements, and microstructural techniques, using X-ray powder diffraction, scanning electron microscopy, and transmission/scanning transmission electron microscopy, were utilized to characterize the positive electrode at different stages of discharge and charge of zinc-ion cells. The results indicate that, during discharge, a fraction of EMD undergoes a transformation to ZnMn2O4 (spinel-type) and Zn2+ is intercalated into the tunnels of the γ- and ε-MnO2 phases, forming ZnxMnO2 (tunnel-type). When a critical concentration of Mn3+ in the intercalated ZnxMnO2 species is reached, a disproportionation/dissolution reaction is triggered leading to the formation of soluble Mn2+ and hydroxide (OH-) ions; the latter precipitates as zinc hydroxide sulfate (ZHS, Zn4(OH)6(SO4)·5H2O) by combination with the ZnSO4/H2O electrolyte. During charge, Zn2+ is reversibly deintercalated from the intergrown tunneled phases (γ-/ε-ZnxMnO2), Mn2+ is redeposited as layered chalcophanite (ZnMn3O7·3H2O), and ZHS is decomposed by protons (H+) formed during the electrochemical deposition of chalcophanite.

Hydrogen electrosorption into Pd-Cd nanostructures.

Hydrogen-absorbing materials are crucial for both the purification and storage of hydrogen. Pd and Pd-based alloys have been studied extensively for their use as both hydrogen dissociation catalysts and hydrogen selective membrane materials. It is known that incorporating metal atoms of different sizes into the Pd lattice has a major impact on the hydrogen absorption process. In this paper, hydrogen electrosorption into nanostructured Pd-Cd alloys has been studied for different compositions of Cd that varied from 0 to 15 at. %. The low cost of Cd makes it an attractive material to combine with Pd for hydrogen sorption. A combination of chronoamperometry and cyclic voltammetric experiments was used to determine the ratio of the H/(Pd + Cd) and the kinetics of hydrogen sorption into these Pd-Cd alloys at different potentials. It was found that the maximum H/(Pd + Cd) value was 0.66 for pure Pd, and this decreased with increasing the amount of Cd. Also, the alpha (solid solution) to beta phase (metal hydride) hydrogen transition was determined to be the slowest step in the absorption process and was practically eliminated when an optimum amount of Cd atoms was doped (i.e., Pd-Cd(15%)). With increasing the amount of Cd, more hydrogen was absorbed into the Pd-Cd nanostructures at the higher potentials (the alpha phase region). The faster kinetics, along with the decrease in the phase transition of hydrogen sorption into the Pd-Cd nanostructures when compared to pure Pd, makes the Pd-Cd nanostructures attractive for use as a hydrogen dissociation catalytic capping layer for other metal hydrides or as a hydrogen selective membrane.

A High-Throughput Small Molecule Screen Identifies Ouabain as Synergistic with miR-34a in Killing Lung Cancer Cells.

MicroRNA-34 (miR-34) is one of the major families of tumor suppressor miRNAs often lost in cancers. Delivery of miR-34a mimics to affected tumors as a therapeutic strategy has been tried in pre-clinical studies and in a phase I clinical trial. One approach to increase efficacy and reduce toxicity is to rationally identify drug combinations with small molecules that synergize with miR-34a. In this study we performed a high-throughput screen of a large panel of small molecules with known biological activity and identified ouabain as a candidate small molecule that synergized with miR-34a in killing lung cancer cells. We elucidated autophagy activation as a key mechanism by which miR-34a and ouabain causes increased cytotoxicity in cells. We posit that this combinatorial approach could reduce the active dose of miR-34a needed in vivo to observe tumor shrinkage and potentiate the development of miR-34a combination therapies in the future.

Argonaute-2 expression is regulated by epidermal growth factor receptor and mitogen-activated protein kinase signaling and correlates with a transformed phenotype in breast cancer cells.

Argonaute (Ago) 2 is the catalytic engine of mammalian RNA interference, but little is known concerning the regulation of Ago2 by cell-signaling pathways. In this study we show that expression of Ago2, but not Ago1, Ago3, or Ago4, is elevated in estrogen receptor (ER) alpha-negative (ERalpha(-)) vs. ERalpha-positive (ERalpha+) breast cancer cell lines, and in ERalpha(-) breast tumors. In MCF-7 cells the low level of Ago2 was found to be dependent upon active ERalpha/estrogen signaling. Interestingly, the high expression of Ago2 in ERalpha(-) cells was severely blunted by inhibition of the epidermal growth factor (EGF) receptor/MAPK signaling pathway, using either a pharmacological MAPK kinase inhibitor, U0126, or a small interfering RNA directed against EGF receptor. Half-life studies using cycloheximide indicated that EGF enhanced, whereas U0126 decreased, Ago2 protein stability. Furthermore, a proteosome inhibitor, MG132, blocked Ago2 protein turnover. The functional consequences of elevated Ago2 levels were examined by stable transfection of ERalpha+ MCF-7 cells with full-length and truncated forms of Ago2. The full-length Ago2 transfectants displayed enhanced proliferation, reduced cell-cell adhesion, and increased migratory ability, as shown by proliferation, homotypic aggregation, and wound healing assays, respectively. Overexpression of full-length Ago2, but not truncated forms of Ago2 or an empty vector control, reduced the levels of E-cadherin, beta-catenin, and beta-actin, as well as enhanced endogenous miR-206 activity. These data indicate that Ago2 is regulated at both the transcriptional and posttranslational level, and also implicate Ago2 and enhanced micro-RNA activity in the tumorigenic progression of breast cancer cell lines.