Clinical status of established MRONJ in oncology patients continuing bone-modifying agents

The continuation of bone-modifying agents (BMAs) in patients with established medication-related osteonecrosis of the jaw (MRONJ) is a common concern among dentists and oncologists. There is little evidence supporting or refuting the continued use of BMAs or drug holidays and their impact on established MRONJ. This paper evaluates the outcome of continued BMAs use on the patient's MRONJ status. A retrospective review of 29 oncology patients undergoing active cancer care for either metastatic disease or multiple myeloma was conducted. Data on demographics, oncological status, BMA history and MRONJ status were collected. In total, 90% of patients were judged to have healed or stable MRONJ while continuing BMAs. Most patients (69%) continued the same BMA regime (three- or four-weekly) that they were on before developing MRONJ. The average number of BMAs doses received after an MRONJ diagnosis was 12 (range 1-48). Three patients (10.3%) were found to have MRONJ progression, with two patients developing new sites of necrosis. This real-world dataset suggests that the majority of MRONJ cases remain stable and will not worsen with the continuation of BMAs.

Cut homeodomain transcription factor is a novel regulator of growth and morphogenesis of cortex glia niche around neural cells

Cortex glia in Drosophila central nervous system form a niche around neural cells for necessary signals to establish cross talk with their surroundings. These cells grow and expand their thin processes around neural cell bodies. Although essential for the development and function of the nervous system, how these cells make extensive and intricate connected networks remains largely unknown. In this study, we show that Cut, a homeodomain transcription factor, directly regulates the fate of the cortex glia, impacting neural stem cell (NSC) homeostasis. Focusing on the thoracic ventral nerve cord, we found that Cut is required for the normal growth and development of cortex glia and timely increase in DNA content through endocycle to later divide via acytokinetic mitosis. Knockdown of Cut in cortex glia significantly reduces the growth of cellular processes, the network around NSCs, and their progeny's cell bodies. Conversely, overexpression of Cut induces overall growth of the main processes at the expense of side ones. Whereas the Cut knockdown slows down the timely increase of DNA, the Cut overexpression results in a significant increase in nuclear size and volume and a 3-fold increase in DNA content of cortex glia. Further, we note that constitutively high Cut also interfered with nuclei separation during acytokinetic mitosis. Since the cortex glia form syncytial networks around neural cells, the finding identifies Cut as a novel regulator of glial growth and variant cell cycles to support a functional nervous system.

ARL15, a GTPase implicated in rheumatoid arthritis, potentially repositions its truncated N-terminus as a function of guanine nucleotide binding

The ADP ribosylation factor like protein 15 (ARL15) gene encodes for an uncharacterized GTPase associated with rheumatoid arthritis (RA) and other metabolic disorders. Investigation of the structural and functional attributes of ARL15 is important to position the protein as a potential drug target. Using spectroscopy, we demonstrated that ARL15 exhibits properties inherent of GTPases. The Km and Vmax of the enzyme were calculated to be 100 μM and 1.47 μmole/min/μL, respectively. The equilibrium dissociation constant (Kd) of GTP binding with ARL15 was estimated to be about eight-fold higher than that of GDP. Small Angle X-ray Scattering (SAXS) data indicated that in solution, the apo state of monomeric ARL15 adopts a shape characterized by a globe of maximum linear dimension (Dmax) of 6.1 nm, and upon binding to GTP or GDP, the vector distribution profile changes to peak-n-tail shoulder with Dmax extended to 7.6 and 7.7 nm, respectively. Structure restoration using a sequence-based template and experimental SAXS data provided the first visual insight revealing that the folded N-terminal in the unbound state of the protein may toggle open upon binding to guanine nucleotides. The conformational dynamics observed in the N-terminal region offer a scope to develop drugs that target this unique GTPase, potentially providing treatments for a range of metabolic disorders.

Mitochondrial Acyl Carrier Protein of Leishmania major Displays Features Distinct from the Canonical Type II ACP

Prokaryotes synthesize fatty acids using a type II synthesis pathway (FAS). In this process, the central player, i.e., the acyl carrier protein (ACP), sequesters the growing acyl chain in its internal hydrophobic cavity. As the acyl chain length increases, the cavity expands in size, which is reflected in the NMR chemical shift perturbations and crystal structures of the acyl-ACP intermediates. A few eukaryotic organelles, such as plastids and mitochondria, also harbor type II fatty acid synthesis machinery. Plastid FAS from spinach and Plasmodium falciparum has been characterized at the molecular level, but the mitochondrial pathway remains unexplored. Here, we report NMR studies of the mitochondrial acyl-acyl carrier protein intermediates of Leishmania major (acyl-LmACP). Our studies show that LmACP experiences remarkably small conformational changes upon acylation, with perturbations confined to helices II and III only. CastP determined that the cavity size of apo-LmACP (PDB entry 5ZWT) is less than that of Escherichia coli ACP (PDB 1T8K). Thus, the small chemical shift perturbations observed in the LmACP intermediates, coupled with CastP results, suggest an unusually small cavity when fully expanded. The faster rate of C8-LmACP chain hydrolysis compared to E. coli ACP (EcACP) also supports these convictions. Structure comparison of LmACP with other type II ACP disclosed unique differences in the helix I and loop I conformations, as well as several residues present there. Numerous hydrophobic residues in helix I and loop I (conserved in all mitochondrial ACPs) are substituted with hydrophilic residues in the bacterial/plastid type II ACP. For instance, Phe and leucine at positions 14 and 34 in LmACP are substituted with a hydrophilic residue and Ala in bacterial/plastid type II ACP. Mutation of Leu 34 to Ala (corresponding residue in EcACP) resulted in a complete loss of structure, underscoring its importance in maintaining the ACP fold. Thus, our NMR studies, combined with insights from the crystal structure, highlight several unique features of LmACP, distinct from the prokaryote and plastid type II ACP. Given the high sequence identity, the features might be conserved in all mitochondrial ACPs.

Survival of Inoculated Vibrio spp., Shigatoxigenic Escherichia coli, Listeria monocytogenes, and Salmonella spp. on Seaweed (Sugar Kelp) During Storage

Bacteria including Vibrio spp. persist in coastal waters and can contaminate edible seaweeds. Pathogens such as Listeria monocytogenes, shigatoxigenic Escherichia coli (STEC), and Salmonella have been associated with and present serious health risks in minimally processed vegetables including seaweeds. This study evaluated the survival of four pathogens inoculated onto two product forms of sugar kelp subjected to different storage temperatures. The inoculation comprised of a cocktail of two Listeria monocytogenes and STEC strains, two Salmonella serovars, and two Vibrio species. STEC and Vibrio were grown and applied in salt-containing media to simulate preharvest contamination, whereas L. monocytogenes and Salmonella inocula were prepared to simulate postharvest contamination. Samples were stored at 4°C and 10°C for 7 days, and 22°C for 8 h. Microbiological analyses were performed periodically (1, 4, 8, 24 h, etc.) to evaluate the effects of storage temperature on pathogen survival. Pathogen populations decreased under all storage conditions, but survival was greatest for all species at 22°C, with STEC exhibiting significantly less reduction (1.8 log CFU/g) than Salmonella, L. monocytogenes, and Vibrio (3.1, 2.7, and 2.7 log CFU/g, respectively) after storage. The largest population reduction (5.3 log CFU/g) was observed in Vibrio stored at 4°C for 7 days. Regardless of storage temperature, all pathogens remained detectable at the end of the study duration. Results emphasize the need for strict adherence to temperature control for kelp as temperature abuse may support pathogen survival, especially STEC, during storage, and the need for prevention of postharvest contamination, particularly with Salmonella.

Justifying the implementation of intraoperative computed tomography for midface fracture treatment in improving outcomes

Intraoperative CT scanning is the international standard for treating midface fractures as it allows intraoperative assessment of reduction and fixation. To our knowledge, no NHS hospital in the UK has this facility yet due to the financial and logistical burden of its implementation. The aim of this study was to determine if complications including the requirement for a return to theatre (RTT) could have been predicted from the post-fixation CT scan. All treated midface fractures that had presented to a regionalised major trauma centre within two years (01 January 2020 - 31 December 2021) were identified. Those developing complications including RTT were determined. All postoperative CT scans (including those without complication or RTT) were re-analysed with the clinicians blinded to the outcomes to determine the positive predictive value (PPV) and negative predictive value (NPV) of requiring RTT to alter plate position intraoperatively based on CT scan alone. In all, there were eight episodes of unplanned return to theatre, resulting in an overall RTT rate of 8/119 (6.7%). When only analysing patients treated for orbital fractures this RTT rises to 8/40 (20%). Of those eight patients who had a postoperative CT and required RTT, this could have been predicted in 7/8 (87.5%). A total of 16/44 (36.4%) patients that did not have RTT would have additionally been recommended to have the plate position altered based on CT alone. Based upon those that had a CT, the PPV of CT alone being able to predict those requiring RTT was 40.6% and the NPV 96.2%. Our results would suggest intraoperative CT would likely have prevented eight patients requiring RTT in two years and could have improved outcomes in 16 cases. In preventing RTT as well as potentially improving the outcomes of a further 16 cases in maxillofacial surgery, the purchase of an intraoperative CT scanner could yield net savings of £75534-£114990 over two years.

Rediscovery of Sewardiella tuberifera Kash., a long-lost monotypic endemic Indian liverwort

An extremely rare, long-lost, monotypic endemic, Indian liverwort, Sewardiella tuberifera Kash. has recently been recollected after a gap of over three-and-a-half decades from an altogether new location, the Mukteshwar region (2,171 m) of Nainital district in the Kumaun Himalaya, Uttarakhand. The remarkable rediscovery of this monotypic, endemic Himalayan liverwort is a significant finding for the world’s bryological treasure. Along with other rare Himalayan monotypic endemics such as Aitchisoniella himalayensis Kash. and Stephensoniella brevipedunculata Kash., the currently located sporiferous population of Sewardiella was discovered persisting in small, dispersed, sparse patches with 5–30 individuals. The currently spotted collection site is being considered a ‘bryological hotspot’. As the area develops as a popular ecotourism destination, the original habitat of these hepatics in a lime stone-dominated, south-west facing, unstable sloppy site at Mukteshwar is under constant pressure from several developmental activities. Hence, serious conservation steps are needed to protect this hotspot supporting Himalayan bryophyte jewels. To ensure long term perpetuation and conservation of red-listed hepatic taxa, an attempt is being made to translocate part of the population to ecologically and climatically identical safer site, including a developing ‘moss garden’ at Lingadhar (Nainital).

E-scooter-related facial injuries: a one-year review following implementation of a citywide trial

Objective Birmingham City Council commenced electric scooter (e-scooter) trials in September 2020 as part of the wider UK effort to introduce e-scooters as an alternative method of transport. We aimed to review and evaluate maxillofacial injuries in the initial trial period of one year and comment on the safety implications.Method The Queen Elizabeth Hospital is a Level 1 Major Trauma Centre and the hub for maxillofacial services in Birmingham, UK. A single-centre retrospective study captured patients who sustained e-scooter-related facial injuries in the Birmingham e-scooter trial period from September 2020 to September 2021.Results A total of 29 patients were identified as having facial injuries. Of those patients: 59% (n = 17) were men and aged under 30; 43% (n = 18) of all injuries recorded involved hard tissue; and 41% (n = 12) were recorded to be under the influence of alcohol or cannabis. The non-use of helmets was recorded in 34% (n = 10) of patients. Additionally, 20 patients were managed operatively and 100% of patients (n = 12) that were under the influence of drugs or alcohol required operative management.Conclusion With the introduction of these trials, it is shown that facial injuries represent a sizeable proportion of all injuries. E-scooters have significant safety issues. Our study may influence legislation to account for improvements in users' compliance with safety measures and enforcement of those using e-scooters illegally. Legislation regarding the future of e-scooters is expected in the coming year as outlined in the 2022 Queen's Speech.

Vocal Fatigue in School Teachers and It's Relation to the Acoustic analysis of Voice

Voice disorders are thought to be one of the major occupational hazards of school teaching. There is a need to study the prevalence of vocal fatigue in school teachers as it is unknown in Indian population and its awareness is at a very basic level. We aim to investigate percentage of school teachers reporting vocal fatigue and to find if there is any relationship between vocal fatigue and acoustic voice parameters. A total of 100 subjects (50-males and 50-females) in the age range of 25-35 years participated in the study. Voice Sample was obtained from the subject using a digital tape recorder and was analyzed in Visi pitch and Dr.Speech softwares. The sample was taken twice in a day, that is, before teaching and after teaching. The mean values obtained on all the questions of the vocal fatigue questionnaire show a significant increase in mean values on all the questions at post teaching ratings. Results revealed a statistically significant difference in pre and post teaching values of F0 and shimmer in males. In females, statistical significant difference was obtained in Noise to Harmonic Ratio in /u/ production. No significant correlation between acoustic parameters and overall vocal fatigue was found except for Noise to Harmonic ratio in females for /u/.

An evaluation of patient informed consent for dental extractions

Dental practitioners are well versed in informing patients of the risks and benefits associated with dental extractions. The purpose of this service evaluation was to determine whether patients understood and recalled information relevant to their planned oral surgery procedure, prior to second stage consent.A questionnaire was distributed to patients who were attending for their elective treatment appointment. This explored their ability to recall the planned intervention, the modality of treatment (local anaesthetic, intravenous sedation, or general anaesthetic), understanding of alternative treatment options and the risks associated with the procedure. Completed responses were received from 29 of the distributed questionnaires (response rate=58%). The majority of patients were not aware of the following risks with their procedure: pain, bleeding, bruising, swelling, infection, damage to adjacent structures.Despite a well-documented consent form and comprehensive discussion, we identified that patients may not comprehend or recollect the risks associated with their dental extraction. As dental professionals we have a duty to seek ways to facilitate patient understanding and maximise their autonomy.

Record-keeping in intravenous sedation: Are we meeting the standards?

As primary care dental services continue to offer conscious sedation in practice, this article presents the findings from a record-keeping audit carried out at a dental teaching hospital in the UK. National guidance was used to set out the gold standards for record-keeping. Various shortcomings in terms of documentation were identified. This article enables dental practitioners involved in dental sedation to review their own sedation record-keeping to meet current national standards and ultimately improve clinical practice and the quality of patient care.

Identification of a polycomb responsive region in human HoxA cluster and its long-range interaction with polycomb enriched genomic regions

Polycomb and Trithorax group proteins (PcG, TrxG) epigenetically regulate developmental genes. These proteins bind with specific DNA elements, the Polycomb Response Element (PRE). Apart from mutations in polycomb/ trithorax proteins, altered cis-elements like PRE underlie the modified function and thus disease etiology. PREs are well studied in Drosophila, while only a few human PREs have been reported. We have identified a polycomb responsive DNA element, hPRE-HoxA3, in the intron of the HoxA3 gene. The hPRE-HoxA3 represses luciferase reporter activity in a PcG-dependent manner. The endogenous hPRE-HoxA3 element recruits PcG proteins and is enriched with repressive H3K27me3 marks, demonstrating that hPRE-HoxA3 is a part of the PcG-dependent gene regulatory network. Furthermore, it interacts with D11-12, the well-known PRE in the human Hox cluster. hPRE-Hox3 is a part of the 3-dimensional chromosomal domain organization as it is involved in the long-range interaction with other PcG enriched regions of Hox A, B, C, and D clusters.

Phenylsulfamoyl Benzoic Acid Inhibitor of ERAP2 with a Novel Mode of Inhibition

ERAP1 and ERAP2 are endoplasmic reticulum zinc-binding aminopeptidases that play crucial roles in processing peptides for loading onto class I major histocompatibility complex proteins. These enzymes are therapeutic targets in cancer and autoimmune disorders. The discovery of inhibitors specific to ERAP1 or ERAP2 has been challenging due to the similarity in their active site residues and domain architectures. Here, we identify 4-methoxy-3-{[2-piperidin-1-yl-4-(trifluoromethyl) phenyl] sulfamoyl} benzoic acid (compound 61) as a novel inhibitor of ERAP2 and determine the crystal structure of ERAP2 bound to compound 61. Compound 61 binds near the catalytic center of ERAP2, at a distinct site from previously known peptidomimetic inhibitors, and inhibits by an uncompetitive mechanism. Surprisingly, for ERAP1, compound 61 was found to activate model substrate hydrolysis, similarly to the previously characterized 5-trifluoromethyl regioisomer of compound 61, known as compound 3. We characterized the specificity determinants of ERAP1 and ERAP2 that control the binding of compounds 3 and 61. At the active site of ERAP1, Lys380 in the S1' pocket is a key determinant for the binding of both compounds 3 and 61. At the allosteric site, ERAP1 binds either compound, leading to the activation of model substrate hydrolysis. Although ERAP2 substrate hydrolysis is not activated by either compound, the mutation of His904 to alanine reveals a cryptic allosteric site that allows for the activation by compound 3. Thus, we have identified selectivity determinants in the active and allosteric sites of ERAP2 that govern the binding of two similar compounds, which potentially could be exploited to develop more potent and specific inhibitors.

Local neighborhood gradient pattern: A feature descriptor for content based image retrieval

Local feature descriptors are efficient encoders for capturing repeated local patterns in many of the computer vision applications. Majority of such descriptors consider only limited local neighborhood pixels to encode a pattern. One of the major issues while considering more number of neighborhood pixels is that it increases the dimensionality of the feature descriptor. The proposed descriptor addresses these issues by describing an effective encoding pattern with optimal feature vector length. In this paper, we have proposed Local Neighborhood Gradient Pattern (LNGP) for Content-Based Image Retrieval (CBIR) in which the relationship between a set of neighbours and the centre pixel is considered to obtain a compact 8-bit pattern in the respective pixel position. The relationship of the gradient information of immediate, next-immediate, and diagonal neighbours with the centre pixel is considered for pattern formation, and thus the local information based on pixels in three directions are captured. The experiments are conducted on benchmarked image retrieval datasets such as Wang’s 1K, Corel 5K, Corel 10K, Salzburg (Stex), MIT-Vistex, AT & T, and FEI datasets and it is observed that the proposed descriptor yields average precision of 71.88%, 54.57%, 40.66%, 71.85%, 86.12%, 82.54%, and 68.54% respectively in the mentioned datasets. The comparative analysis of the recent descriptors indicates that the proposed descriptor performs efficiently in CBIR applications.

Structural Models for Roseolovirus U20 And U21: Non-Classical MHC-I Like Proteins From HHV-6A, HHV-6B, and HHV-7

Human roseolovirus U20 and U21 are type I membrane glycoproteins that have been implicated in immune evasion by interfering with recognition of classical and non-classical MHC proteins. U20 and U21 are predicted to be type I glycoproteins with extracytosolic immunoglobulin-like domains, but detailed structural information is lacking. AlphaFold and RoseTTAfold are next generation machine-learning-based prediction engines that recently have revolutionized the field of computational three-dimensional protein structure prediction. Here, we review the structural biology of viral immunoevasins and the current status of computational structure prediction algorithms. We use these computational tools to generate structural models for U20 and U21 proteins, which are predicted to adopt MHC-Ia-like folds with closed MHC platforms and immunoglobulin-like domains. We evaluate these structural models and place them within current understanding of the structural basis for viral immune evasion of T cell and natural killer cell recognition.

An overview of the fatty acid biosynthesis in the protozoan parasite Leishmania and its relevance as a drug target against leishmaniasis

Leishmaniasis is one of the fast-growing parasitic diseases worldwide. The treatment of this fatal disease presents a daunting challenge because of its adverse effects, necessity for long-term treatment regime, unavailability of functional drugs, emergence of drug resistance and the related expenditure. This calls for an urgent need for novel drugs and the evaluation of new targets. Proteins of the fatty acid biosynthetic pathway are validated as drug targets in pathogenic bacteria and certain viruses. Likewise, this pathway has been speculated as a suitable target against parasite infections. Fatty acid synthesis in parasites seems to be very complex and distinct from the counterpart mammalian host due to the presence of unique mechanisms for fatty acid biosynthesis and acquisition. In recent times, there have been few evidences of the existence of this pathway in the bloodstream form of some pathogens. The fatty acid biosynthesis thus presents a viable and attractive target for emerging therapeutics. Understanding the mechanisms underlying fatty acid metabolism is key to identifying a potential drug target. However, investigations in this direction are still limited and this article attempts to outline the existing knowledge, while highlighting the scope and relevance of the fatty acid biosynthetic pathway as a drug target. This review highlights the advances in the treatment of leishmaniasis, the importance of lipids in the pathogen, known facts about the fatty acid biosynthesis in Leishmania and how this pathway can be manipulated to combat leishmaniasis, suggesting novel drug targets.

Conformational dynamics linked to domain closure and substrate binding explain the ERAP1 allosteric regulation mechanism

The endoplasmic-reticulum aminopeptidase ERAP1 processes antigenic peptides for loading on MHC-I proteins and recognition by CD8 T cells as they survey the body for infection and malignancy. Crystal structures have revealed ERAP1 in either open or closed conformations, but whether these occur in solution and are involved in catalysis is not clear. Here, we assess ERAP1 conformational states in solution in the presence of substrates, allosteric activators, and inhibitors by small-angle X-ray scattering. We also characterize changes in protein conformation by X-ray crystallography, and we localize alternate C-terminal binding sites by chemical crosslinking. Structural and enzymatic data suggest that the structural reconfigurations of ERAP1 active site are physically linked to domain closure and are promoted by binding of long peptide substrates. These results clarify steps required for ERAP1 catalysis, demonstrate the importance of conformational dynamics within the catalytic cycle, and provide a mechanism for the observed allosteric regulation and Lys/Arg528 polymorphism disease association.

L. major apo-acyl carrier protein forms ordered aggregates due to an exposed phenylalanine, while phosphopantetheine inhibits aggregation in the holo-form

L. major acyl carrier protein (ACP) is a mitochondrial protein, involved in fatty acid biosynthesis. The protein is expressed as an apo-protein, and post-translationally modified at Ser 37 by a 4'-Phosphopantetheinyl transferase. Crystal structure of the apo-form of the protein at pH 5.5 suggests a four helix bundle fold, typical of ACP's. However, upon lowering the pH to 5.0, it undergoes a conformational transition from α-helix to β-sheet, and displays amyloid like properties. When left for a few days at room temperature at this pH, the protein forms fibrils, visible under Transmission electron microscopy (TEM). Using an approach combining NMR, biophysical techniques, and mutagenesis, we have identified a Phe residue present on helix II of ACP, liable for this change. Phosphopantetheinylation of LmACP, or mutation of Phe 45 to the corresponding residue in E. coli ACP (methionine), slows down the conformational change. Conversely, substitution of methionine 44 of E. coli ACP with a phenylalanine, causes enhanced ThT binding. Thus, we demonstrate the unique property of an exposed Phe in inducing, and phophopantetheine in inhibiting amyloidogenesis. Taken together, our study adds L. major acyl carrier protein to the list of ACPs that act as pH sensors.

Renal salt-wasting syndrome induced by neoadjuvant chemotherapy containing cisplatin – A case report

Hyponatremia is one of the most common electrolyte abnormality seen in oncology practice. The underlying pathogenetic mechanism for chemotherapy-induced hyponatremia is renal salt-wasting syndrome (RSWS) and syndrome of inappropriate antidiuretic hormone secretion (SIADH). Fluid restriction is the treatment of choice in SIADH, whereas salt supplements is the mode of treatment in RSWS. Hence, differentiation between RSWS and SIADH is very important though difficult. Case reports of cisplatin (cis-dichloro-diammine-platinum-2)-induced RSWS and SIADH are rare in the literature. We report about a patient who developed hyponatremia, hypokalemia with excessive urinary excretion of sodium and potassium, renal glycosuria, and aminoaciduria on the third day of the first cycle of cisplatin-containing chemotherapy.

In-silico Studies and Biological Activity of Potential BACE-1 Inhibitors

BACKGROUND

Alzheimer's disease is a neurological condition causing cognitive inability and dementia. The pathological lesions and neuronal damage in the brain are caused by self-aggregated fragments of mutated Amyloidal precursor protein (APP).

OBJECTIVE

The controlled APP processing by inhibition of secretase is the strategy to reduce Aβ load to treat Alzheimer's disease.

METHODS

A QSAR study was performed on 55 Pyrrolidine based ligands as BACE-1 inhibitors with an activity magnitude greater than 4 of compounds.

RESULTS

In the advent of designing new BACE-1 inhibitors, the pharmacophore model with correlation (r = 0.90) and root mean square deviation (RMSD) of 0.87 was developed and validated. Further, the hits retrieved by the in-silico approach were evaluated by docking interactions.

CONCLUSION

Two structurally diverse compounds exhibited Asp32 and Thr232 binding with the BACE-1 receptor. The aryl-substituted carbamate compound exhibited the highest fit value and docking score. The biological activity evaluation by in-vitro assay was found to be >0.1μM.

A systematic re-examination of processing of MHCI-bound antigenic peptide precursors by endoplasmic reticulum aminopeptidase 1

Endoplasmic reticulum aminopeptidase 1 (ERAP1) trims antigenic peptide precursors to generate mature antigenic peptides for presentation by major histocompatibility complex class I (MHCI) molecules and regulates adaptive immune responses. ERAP1 has been proposed to trim peptide precursors both in solution and in preformed MHCI-peptide complexes, but which mode is more relevant to its biological function remains controversial. Here, we compared ERAP1-mediated trimming of antigenic peptide precursors in solution or when bound to three MHCI alleles, HLA-B*58, HLA-B*08, and HLA-A*02. For all MHCI-peptide combinations, peptide binding onto MHCI protected against ERAP1-mediated trimming. In only a single MHCI-peptide combination, trimming of an HLA-B*08-bound 12-mer progressed at a considerable rate, albeit still slower than in solution. Results from thermodynamic, kinetic, and computational analyses suggested that this 12-mer is highly labile and that apparent on-MHC trimming rates are always slower than that of MHCI-peptide dissociation. Both ERAP2 and leucine aminopeptidase, an enzyme unrelated to antigen processing, could trim this labile peptide from preformed MHCI complexes as efficiently as ERAP1. A pseudopeptide analogue with high affinity for both HLA-B*08 and the ERAP1 active site could not promote the formation of a ternary ERAP1/MHCI/peptide complex. Similarly, no interactions between ERAP1 and purified peptide-loading complex were detected in the absence or presence of a pseudopeptide trap. We conclude that MHCI binding protects peptides from ERAP1 degradation and that trimming in solution along with the dynamic nature of peptide binding to MHCI are sufficient to explain ERAP1 processing of antigenic peptide precursors.

In-Silico QSAR Modelling of Predicted Rho Kinase Inhibitors Against Cardio Vascular Diseases

BACKGROUND

Rho-kinase is an essential downstream target of GTP-binding protein RhoA, and plays a crucial role in the calcium-sensitization pathway. Rho-kinase pathway is critically involved in phosphorylation state of myosin light chain, leading to increased contraction of smooth muscles. Inhibition of this pathway has turned out to be a promising target for several indications such as cardiovascular diseases, glaucoma and inflammatory diseases.

METHODS

The present work focuses on a division-based 2D quantitative structure-activity relationship (QSAR) analysis along with a docking study to predict structural features that may be essential for the enhancement of selectivity and potency of the target compounds. Furthermore, a set of indoles and azaindoles were also projected based on the regression equation as novel developments. Molecular docking was applied for exploring the binding sites of the newly predicted set of compounds with the receptor.

RESULTS

Results of the docked conformations suggested that introduction of non-bulky and substituted groups in the hinge region of ROCK-II ATP binding pocket would improve the activity by decreasing the bulkiness or length of the compounds.

CONCLUSION

ADME studies were performed to ascertain the novelty and drug-like properties of the designed molecules, respectively.

Discovery of Selective Inhibitors of Endoplasmic Reticulum Aminopeptidase 1

ERAP1 is an endoplasmic reticulum-resident zinc aminopeptidase that plays an important role in the immune system by trimming peptides for loading onto major histocompatibility complex proteins. Here, we report discovery of the first inhibitors selective for ERAP1 over its paralogues ERAP2 and IRAP. Compound 1 (N-(N-(2-(1H-indol-3-yl)ethyl)carbamimidoyl)-2,5-difluorobenzenesulfonamide) and compound 2 (1-(1-(4-acetylpiperazine-1-carbonyl)cyclohexyl)-3-(p-tolyl)urea) are competitive inhibitors of ERAP1 aminopeptidase activity. Compound 3 (4-methoxy-3-(N-(2-(piperidin-1-yl)-5-(trifluoromethyl)phenyl)sulfamoyl)benzoic acid) allosterically activates ERAP1's hydrolysis of fluorogenic and chromogenic amino acid substrates but competitively inhibits its activity toward a nonamer peptide representative of physiological substrates. Compounds 2 and 3 inhibit antigen presentation in a cellular assay. Compound 3 displays higher potency for an ERAP1 variant associated with increased risk of autoimmune disease. These inhibitors provide mechanistic insights into the determinants of specificity for ERAP1, ERAP2, and IRAP and offer a new therapeutic approach of specifically inhibiting ERAP1 activity in vivo.

Speech Perception Skills of Hindi Speaking Children with Pre-lingual Hearing Loss Using Hearing Aids and Cochlear Implants

Very few published studies have reported auditory speech perception in Hindi children with pre-lingual hearing loss. The study is aimed at comparing the speech perception skills of Hindi speaking children with pre-lingual severe to profound hearing loss using hearing aids and cochlear implants. Forty-three 6 to 8-year old children were included as participants, of which 22 were bilateral behind-the-ear hearing aid (HA) users and 21 were unilateral cochlear implant (CI) users. Speech perception was assessed through a forced-choice, picture-pointing task using recorded stimuli presented at 70 dB HL in the sound field. The skills assessed include: (a) pattern perception, (b) bisyllabic word identification, (c) monosyllabic word identification, (d) sentence identification and (e) minimal pair identification. Children using CI consistently performed significantly better than those with HA on all tasks. For the skills assessed, best performance was seen in pattern perception and poorest performance was seen in monosyllabic word identification. One participant from the CI group obtained ceiling scores for pattern perception and bisyllabic word identification. There was no statistically significant difference in the performance of 6 to 7 and 7 to 8-year-old children for any of the tasks. Children fitted with CI have better access to the cues important for perception of speech and hence perform consistently better than those using hearing aids. Recorded speech perception test can be used with children using cochlear implants and hearing aids.

Pharmacophore Modeling and Docking Studies to Investigate Potential Leads for the Development of β -Secretase APP Cleavage Enzyme-1 (BACE-1) Inhibitors

Background:

Alzheimer’s disease is a medical condition with detrimental brain health. It is majorly diagnosed in aging individuals plaque in β) characterized by accumulated Amyloidal beta (A 1 BACE) 1 secretase APP cleavage enzyme βneurological areas. The ) is the target of choice that can be exploited to find drugs against Alzheimer’s disease.

Methods:

A series of BACE-1 inhibitors with reported binding constant were considered for the development of a feature based pharmacophore model.

Results:

The good correlation coefficient (r=0.91) and RMSD of 0.93 was observed with 30 compounds in training set. The model was validated internally (r2test=0.76) as well as externally by Fischer validation. The pharmacophore based virtual screening retrieved compounds that were docked and biologically evaluated.

Conclusion:

The three structurally diverse molecules were tested by in-vitro method. The pyridine derivative with highest fit value (6.9) exhibited IC50 value of 2.70 µM and thus was found to be the most promising lead molecule as BACE-1 inhibitor.

QSAR and Molecular Modeling Studies on a Series of Pyrrolidine Analogs Acting as BACE-1 Inhibitors

Background:

β-Site amyloidal precursor protein (APP) cleavage enzyme (BACE-1) is reported as prime cause for progession of Alzheimer’s disease (AD). It is a form of dementia characterized by degeneration of neurones in brain. Therefore, attempts have been made to find potent inhibitors of this enzyme.

Methods:

The paper presents an division-based 2D quantitative structure-activity relationship (QSAR) study on a series of BACE-1 inhibitors to analyse the structural features that may be important to increase the potency of the compounds.

Results:

The study led to predict some potential leads for the development of potent inhibitors of BACE-1. One of the molecule with pyrrolidine and pyrrolidinone substitutions exhibited drugreceptor interactions comparable with reference drug.

Conclusion:

The hydrogen-bond interactions between the molecules and the receptor basically control the BACE-1 inhibition activity of the compounds.

A Cut/cohesin axis alters the chromatin landscape to facilitate neuroblast death

Precise control of cell death in the nervous system is essential for development. Spatial and temporal factors activate the death of Drosophila neural stem cells (neuroblasts) by controlling the transcription of multiple cell death genes through a shared enhancer. The activity of this enhancer is controlled by abdominal A and Notch, but additional inputs are needed for proper specificity. Here, we show that the Cut DNA binding protein is required for neuroblast death, regulating reaper and grim downstream of the shared enhancer and of abdominal A expression. The loss of cut accelerates the temporal progression of neuroblasts from a state of low overall levels of H3K27me3 to a higher H3K27me3 state. This is reflected in an increase in H3K27me3 modifications in the cell death gene locus in the CNS on Cut knockdown. We also show that cut regulates the expression of the cohesin subunit Stromalin. Stromalin and the cohesin regulatory subunit Nipped-B are required for neuroblast death, and knockdown of Stromalin increases H3K27me3 levels in neuroblasts. Thus, Cut and cohesin regulate apoptosis in the developing nervous system by altering the chromatin landscape.

Craniospinal Irradiation in Medulloblastoma using High Energy Medical Linear Accelerator: an Innovative Approach to Planning Technique

BACKGROUND

Craniospinal irradiation (CSI) of medulloblastoma poses technological challenges due to the involvement of large treatment volume. Commonly, the whole treatment length is covered with two different isocentric plans in which the junction is shifted after every five fractions to overcome the possibility of hot and cold spot.

OBJECTIVE

This study aims to evaluate dosimetrically and clinically the innovative planning technique for the CSI which doesn't need re-planning and re-setup of patients after every five fractions.

MATERIAL AND METHODS

Computed tomography was done for fifteen (ten children and five adults) patients diagnosed with medulloblastoma. Treatment planning for 36 Gray (Gy) in 20 fractions (#) at the rate of 1.8Gy/# was done on the treatment planning system. A single plan for children was created with two bilateral fields of 6 Mega Voltage (MV) energy for cranium and one posterior field of 6 MV for spinal cord (C1-S2). Two plans for adult patients were created, first plan was with two bilateral fields of 6 MV for cranium and two posterior oblique fields of 6 MV for cervical and the part of thoracic spinal cord (up to T8-T9). The second plan was with a single posterior field of 15 MV covering remaining thoracic (T8-T9 to T12), lumbar and sacrum (up to lower border of S2) spine. After careful evaluation of all the plans, treatment was delivered; acute toxicities were recorded.

RESULTS

95% of prescribed dose was received by more than 95% of planning target volume in all the plans with the acceptable hot spot and good homogeneity index. All the patients reported common radiation induced acute toxicities (headache, vomiting, weakness) during radiotherapy.

CONCLUSION

The new planning technique for CSI has acceptable dosimetric and acute clinical possibilities; therefore it can be used for CSI for improved homogeneous dose delivery.