Asciminib in Newly Diagnosed Chronic Myeloid Leukemia.

BACKGROUND: Patients with newly diagnosed chronic myeloid leukemia (CML) need long-term therapy with high efficacy and safety. Asciminib, a BCR::ABL1 inhibitor specifically targeting the ABL myristoyl pocket, may offer better efficacy and safety and fewer side effects than currently available frontline ATP-competitive tyrosine kinase inhibitors (TKIs). METHODS: In a phase 3 trial, patients with newly diagnosed CML were randomly assigned in a 1:1 ratio to receive either asciminib (80 mg once daily) or an investigator-selected TKI, with randomization stratified by European Treatment and Outcome Study long-term survival score category (low, intermediate, or high risk) and by TKI selected by investigators before randomization (including imatinib and second-generation TKIs). The primary end points were major molecular response (defined as BCR::ABL1 transcript levels ≤0.1% on the International Scale [IS]) at week 48, for comparisons between asciminib and investigator-selected TKIs and between asciminib and investigator-selected TKIs in the prerandomization-selected imatinib stratum. RESULTS: A total of 201 patients were assigned to receive asciminib and 204 to receive investigator-selected TKIs. The median follow-up was 16.3 months in the asciminib group and 15.7 months in the investigator-selected TKI group. A major molecular response at week 48 occurred in 67.7% of patients in the asciminib group, as compared with 49.0% in the investigator-selected TKI group (difference, 18.9 percentage points; 95% confidence interval [CI], 9.6 to 28.2; adjusted two-sided P<0.001]), and in 69.3% of patients in the asciminib group as compared with 40.2% in the imatinib group within the imatinib stratum (difference, 29.6 percentage points; 95% CI, 16.9 to 42.2; adjusted two-sided P<0.001). The percentage of patients with a major molecular response at week 48 was 66.0% with asciminib and 57.8% with TKIs in the second-generation TKI stratum (difference, 8.2 percentage points; 95% CI, -5.1 to 21.5). Adverse events of grade 3 or higher and events leading to discontinuation of the trial regimen were less frequent with asciminib (38.0% and 4.5%, respectively) than with imatinib (44.4% and 11.1%) and second-generation TKIs (54.9% and 9.8%). CONCLUSIONS: In this trial comparing asciminib with investigator-selected TKIs and imatinib, asciminib showed superior efficacy and a favorable safety profile in patients with newly diagnosed chronic-phase CML. Direct comparison between asciminib and second-generation TKIs was not a primary objective. (Funded by Novartis; ASC4FIRST ClinicalTrials.gov number, NCT04971226).

Effect of capmatinib on the pharmacokinetics of substrates of CYP3A (midazolam) and CYP1A2 (caffeine) in patients with MET-dysregulated solid tumours.

BACKGROUND: Preclinical studies showed that capmatinib reversibly inhibits cytochrome P450 (CYP) 3A4 and CYP1A2 in a time-dependent manner. In this study, we evaluated the effect of capmatinib on the exposure of sensitive substrates of CYP3A (midazolam) and CYP1A2 (caffeine) in patients with mesenchymal-epithelial transition (MET)-dysregulated solid tumours. Besides pharmacokinetics, we assessed treatment response and safety. METHODS: This open-label, multicentre, single-sequence study consisted of a molecular prescreening period, a screening/baseline period of ≤28 days and a drug-drug interaction (DDI) phase of 12 days. On day 1 of the DDI phase, 37 patients received a single oral dose of midazolam 2.5 mg and caffeine 100 mg as a two-drug cocktail. Capmatinib 400 mg bid was administered from day 4 on a continuous dosing schedule. On day 9 of the DDI phase, patients were re-exposed to midazolam and caffeine. After the DDI phase, patients received capmatinib on continuous 21-day cycles until disease progression at the discretion of the investigator. RESULTS: A 22% (90% confidence interval [CI] 7-38%) increase in the midazolam maximum plasma concentration (Cmax ) was noted when administered with capmatinib, but this was deemed not clinically meaningful. Co-administration with capmatinib resulted in 134% (90% CI 108-163%) and 122% (90% CI 95-153%) increases in the caffeine area under the plasma concentration-time curve from time zero to infinity (AUCinf ) and area under the plasma concentration-time curve from time zero to the last measurable point (AUClast ), respectively, with no change in Cmax . Adverse events were consistent with the known capmatinib safety profile. No new safety signals were reported in this study. CONCLUSION: The data from this study demonstrated that capmatinib is a moderate CYP1A2 inhibitor. Capmatinib administration did not cause any clinically relevant changes in midazolam exposure.

Pharmacokinetics of capmatinib in participants with hepatic impairment: A phase 1, open-label, single-dose, parallel-group study.

AIMS: Capmatinib, a mesenchymal-epithelial transition factor tyrosine kinase inhibitor, is metabolized by cytochrome P450 (CYP) 3A4 and aldehyde oxidase. In individuals with hepatic impairment, alterations in hepatobiliary excretion and metabolism could lead to higher capmatinib exposure. We compared the pharmacokinetics of a single oral dose of capmatinib 200 mg administered to participants with varying degrees of hepatic impairment vs. matched controls with normal hepatic function. METHODS: This phase 1, multicentre, open-label, parallel-group study enrolled adult participants with normal hepatic function and mild, moderate and severe hepatic impairments. Eligible participants received a single oral dose of 200 mg capmatinib. The pharmacokinetic parameters of capmatinib were analysed and compared across participants with impaired and normal hepatic function. RESULTS: Of 31 enrolled participants, 29 had an evaluable pharmacokinetic profile: normal (n = 9); mild (n = 6); moderate (n = 8); severe (n = 6). Compared with the normal group, geometric mean (GM) maximum (peak) observed plasma drug concentration after single-dose administration decreased by 27.6% in the mild group (GM ratio [GMR] = 0.724; 90% confidence interval [CI]: 0.476-1.10), by 17.2% in the moderate group (GMR = 0.828; 90% CI: 0.563-1.22) and remained unchanged in the severe group (GMR = 1.02; 90% CI: 0.669-1.55). Compared with the normal group, GM area under the plasma concentration-time curve from time zero to infinity decreased by 23.3% in the mild group (GMR = 0.767; 90% CI: 0.532-1.11), by 8.6% in the moderate group (GMR = 0.914; 90% CI: 0.652-1.28) and increased by 24% in the severe group (GMR = 1.24; 90% CI: 0.858-1.78). CONCLUSION: Mild, moderate and severe hepatic impairment did not have a clinically relevant impact on capmatinib pharmacokinetics. No new safety findings are reported in this study.

Rescue of neural crest-derived phenotypes in a zebrafish CHARGE model by Sox10 downregulation.

CHD7 mutations are implicated in a majority of cases of the congenital disorder, CHARGE syndrome. CHARGE, an autosomal dominant syndrome, is known to affect multiple tissues including eye, heart, ear, craniofacial nerves and skeleton and genital organs. Using a morpholino-antisense-oligonucleotide-based zebrafish model for CHARGE syndrome, we uncover a complex spectrum of abnormalities in the neural crest and the crest-derived cell types. We report for the first time, defects in myelinating Schwann cells, enteric neurons and pigment cells in a CHARGE model. We also observe defects in the specification of peripheral neurons and the craniofacial skeleton as previously reported. Chd7 morphants have impaired migration of neural crest cells and deregulation of sox10 expression from the early stages. Knocking down Sox10 in the zebrafish CHARGE model rescued the defects in Schwann cells and craniofacial cartilage. Our zebrafish CHARGE model thus reveals important regulatory roles for Chd7 at multiple points of neural crest development viz., migration, fate choice and differentiation and we suggest that sox10 deregulation is an important driver of the neural crest-derived aspects of Chd7 dependent CHARGE syndrome.

Chemical and genetic rescue of an ep300 knockdown model for Rubinstein Taybi Syndrome in zebrafish.

EP300 is a member of the EP300/CBP family of lysine acetyltransferases (KATs) with multiple roles in development and physiology. Loss of EP300/CBP activity in humans causes a very rare congenital disorder called Rubinstein Taybi Syndrome (RSTS). The zebrafish genome has two co-orthologs of lysine acetyltransferase EP300 (KAT3B) in zebrafish viz. ep300a and ep300b. Chemical inhibition of Ep300 with C646, a competitive inhibitor and morpholino-based genetic knockdown of ep300a and ep300b cause defects in embryonic development reminiscent of the human RSTS syndrome. Remarkably, overexpression of Ep300a KAT domain results in near complete rescue of the jaw development defects, a characteristic feature of RSTS in human suggesting the dispensability of the protein-interaction and DNA-binding domains for at least some developmental roles of Ep300. We also perform a chemical screen and identify two inhibitors of deacetylases, CHIC35 and HDACi III, that can partially rescue the RSTS-like phenotypes. Thus, modeling rare human genetic disorders in zebrafish allows for functional understanding of the genes involved and can also yield small molecule candidates towards therapeutic goals.

Computational approaches towards understanding human long non-coding RNA biology.

Long non-coding RNAs (lncRNAs) form the largest class of non-protein coding genes in the human genome. While a small subset of well-characterized lncRNAs has demonstrated their significant role in diverse biological functions like chromatin modifications, post-transcriptional regulation, imprinting etc., the functional significance of a vast majority of them still remains an enigma. Increasing evidence of the implications of lncRNAs in various diseases including cancer and major developmental processes has further enhanced the need to gain mechanistic insights into the lncRNA functions. Here, we present a comprehensive review of the various computational approaches and tools available for the identification and annotation of long non-coding RNAs. We also discuss a conceptual roadmap to systematically explore the functional properties of the lncRNAs using computational approaches.

Cervical epidural blood patch--A literature review.

OBJECTIVE: Epidural blood patches (EBP) are rarely performed at the cervical levels, primarily due to fear of neurological complications such as spinal cord compression. We reviewed the literature to provide an evidence-based review of performance of cervical EBPs, with a specific focus on indication, technique, safety, and efficacy. DESIGN: A comprehensive electronic literature search was done to include studies that reported on performance of cervical EBPs in patients with CSF leak at the cervical level. Data regarding indication, level of CSF leak, level of cervical EBP, volume of blood used, efficacy, and complications were collected. RESULTS: A total of 15 studies, reporting on 19 patients were included. All patients presented with a headache that increased in the standing position, and improved in the supine position. All patients were identified to have a CSF leak at the cervical level. Eight patients first underwent a lumbar EBP, without complete, long-term relief. All these patients, along with 11 patients who did not undergo a lumbar EPB prior to cervical EBP, reported complete, long-term pain relief. EBPs were mostly done in the prone position, using imaging guidance. An average of 5-8 mL of autologous blood was injected in the epidural space. No major neurological complications were reported in any patient. CONCLUSION: The review suggests that cervical EBP can be performed for cervical CSF leaks associated with positional headache without a significant risk of serious adverse events. CLASSIFICATION OF EVIDENCE: Our review provides Class II level of evidence that cervical EBPs are safe and effective in reliving positional headache due to CSF leak.

Analgesic management of acute pain in the opioid-tolerant patient.

PURPOSE OF REVIEW: The management of acute pain in the opioid-tolerant patient is an area in perioperative medicine that is growing, as the use of opioids for chronic noncancer pain has been tolerated in the USA. Adding to this population is an increase in opioid abusers, addicts and those in recovery and maintenance programmes. These patients will continue to present for surgery and with acute pain that anaesthesiologists and other members of the healthcare team must become more adept at managing. RECENT FINDINGS: This review covers some of the strategies that may be used by practitioners in the management of acute pain in the opioid-tolerant patient. It is important to collect a detailed history of opioid and drugs of abuse, including the timing of the last dose in order to avoid precipitation of withdrawal. The use of multimodal anaesthetic and analgesic strategies is important for both patient safety and satisfaction and can enhance recovery and discharge home. SUMMARY: There is a need for more high-level evidence-based guidelines to help practitioners achieve the best care of this growing high-risk population of patients.

Revitalizing Cancer Treatment: Exploring the Role of Drug Repurposing.

Cancer persists as a global challenge necessitating continual innovation in treatment strategies. Despite significant advancements in comprehending the disease, cancer remains a leading cause of mortality worldwide, exerting substantial economic burdens on healthcare systems and societies. The emergence of drug resistance further complicates therapeutic efficacy, underscoring the urgent need for alternative approaches. Drug repurposing, characterized by the utilization of existing drugs for novel clinical applications, emerges as a promising avenue for addressing these challenges. Repurposed drugs, comprising FDA-approved (in other disease indications), generic, off-patent, and failed medications, offer distinct advantages including established safety profiles, cost-effectiveness, and expedited development timelines compared to novel drug discovery processes. Various methodologies, such as knowledge-based analyses, drug-centric strategies, and computational approaches, play pivotal roles in identifying potential candidates for repurposing. However, despite the promise of repurposed drugs, drug repositioning confronts formidable obstacles. Patenting issues, financial constraints associated with conducting extensive clinical trials, and the necessity for combination therapies to overcome the limitations of monotherapy pose significant challenges. This review provides an in-depth exploration of drug repurposing, covering a diverse array of approaches including experimental, re-engineering protein, nanotechnology, and computational methods. Each of these avenues presents distinct opportunities and obstacles in the pursuit of identifying novel clinical uses for established drugs. By examining the multifaceted landscape of drug repurposing, this review aims to offer comprehensive insights into its potential to transform cancer therapeutics.

Dose Justification for Asciminib in Patients with Philadelphia Chromosome-Positive Chronic Myeloid Leukemia with and Without the T315I Mutation.

BACKGROUND AND OBJECTIVE: Asciminib is approved in patients with Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase (Ph+ CML-CP) treated with ≥ 2 prior tyrosine kinase inhibitors. Here, we aimed to demonstrate similarity in efficacy/safety of asciminib 80 mg once daily (q.d.) versus 40 mg twice daily (b.i.d.) in patients with CML-CP without T315I mutation and support the use of the 200-mg b.i.d. dosage in patients harboring T315I, using model-informed drug development. METHODS: Data were collected from 199 patients in the phase I (NCT02081378; 10-200 mg b.i.d. or 10-400 mg q.d.) and 154 patients in the phase III (NCT03106779; 40 mg b.i.d.) studies. Evaluations were based on population pharmacokinetics (PopPK) and exposure-response (efficacy/safety) analyses. RESULTS: PopPK showed comparable exposure (area under the curve, AUC0-24h) for 40 mg b.i.d. and 80 mg q.d. (12,638 vs 12,646 ng*h/mL); average maximum and minimum plasma concentrations for 80 mg q.d. were 1.61- and 0.72-fold those of 40 mg b.i.d., respectively. Exposure-response analyses predicted similar major molecular response rates for 40 mg b.i.d. and 80 mg q.d. (Week 24: 27.6% vs 24.8%; Week 48: 32.3% vs 30.6%). Results also established adequacy of 200 mg b.i.d. in patients with T315I mutation (Week 24: 20.7%; Week 48: 23.7%), along with a similar safety profile for all dose regimens. CONCLUSIONS: Similarity between 40 mg b.i.d. and 80 mg q.d. regimens was investigated, demonstrating similar and substantial efficacy with well-tolerated safety in patients without T315I mutation. The 200-mg b.i.d. dose was deemed safe and effective for patients with T315I mutation.

Decoding the genetic symphony: Profiling protein-coding and long noncoding RNA expression in T-acute lymphoblastic leukemia for clinical insights.

T-acute lymphoblastic leukemia (T-ALL) is a heterogeneous malignancy characterized by the abnormal proliferation of immature T-cell precursors. Despite advances in immunophenotypic classification, understanding the molecular landscape and its impact on patient prognosis remains challenging. In this study, we conducted comprehensive RNA sequencing in a cohort of 35 patients with T-ALL to unravel the intricate transcriptomic profile. Subsequently, we validated the prognostic relevance of 23 targets, encompassing (i) protein-coding genes-BAALC, HHEX, MEF2C, FAT1, LYL1, LMO2, LYN, and TAL1; (ii) epigenetic modifiers-DOT1L, EP300, EML4, RAG1, EZH2, and KDM6A; and (iii) long noncoding RNAs (lncRNAs)-XIST, PCAT18, PCAT14, LINC00202, LINC00461, LINC00648, ST20, MEF2C-AS1, and MALAT1 in an independent cohort of 99 patients with T-ALL. Principal component analysis revealed distinct clusters aligning with immunophenotypic subtypes, providing insights into the molecular heterogeneity of T-ALL. The identified signature genes exhibited associations with clinicopathologic features. Survival analysis uncovered several independent predictors of patient outcomes. Higher expression of MEF2C, BAALC, HHEX, and LYL1 genes emerged as robust indicators of poor overall survival (OS), event-free survival (EFS), and relapse-free survival (RFS). Higher LMO2 expression was correlated with adverse EFS and RFS outcomes. Intriguingly, increased expression of lncRNA ST20 coupled with RAG1 demonstrated a favorable prognostic impact on OS, EFS, and RFS. Conclusively, several hitherto unreported associations of gene expression patterns with clinicopathologic features and prognosis were identified, which may help understand T-ALL's molecular pathogenesis and provide prognostic markers.

Asciminib vs bosutinib in chronic-phase chronic myeloid leukemia previously treated with at least two tyrosine kinase inhibitors: longer-term follow-up of ASCEMBL.

Asciminib, the first BCR::ABL1 inhibitor that Specifically Targets the ABL Myristoyl Pocket (STAMP), is approved worldwide for the treatment of adults with Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase (CML-CP) treated with ≥2 prior tyrosine kinase inhibitors (TKIs). In ASCEMBL, patients with CML-CP treated with ≥2 prior TKIs were randomized (stratified by baseline major cytogenetic response [MCyR]) 2:1 to asciminib 40 mg twice daily or bosutinib 500 mg once daily. Consistent with previously published primary analysis results, after a median follow-up of 2.3 years, asciminib continued to demonstrate superior efficacy and better safety and tolerability than bosutinib. The major molecular response (MMR) rate at week 96 (key secondary endpoint) was 37.6% with asciminib vs 15.8% with bosutinib; the MMR rate difference between the arms, after adjusting for baseline MCyR, was 21.7% (95% CI, 10.53-32.95; two-sided p = 0.001). Fewer grade ≥3 adverse events (AEs) (56.4% vs 68.4%) and AEs leading to treatment discontinuation (7.7% vs 26.3%) occurred with asciminib than with bosutinib. A higher proportion of patients on asciminib than bosutinib remained on treatment and continued to derive benefit over time, supporting asciminib as a standard of care for patients with CML-CP previously treated with ≥2 TKIs.

Pharmacokinetics of asciminib in the presence of CYP3A or P-gp inhibitors, CYP3A inducers, and acid-reducing agents.

Asciminib is a first-in-class inhibitor of BCR::ABL1, specifically targeting the ABL myristoyl pocket. Asciminib is a substrate of CYP3A4 and P-glycoprotein (P-gp) and possesses pH-dependent solubility in aqueous solution. This report summarizes the results of two phase I studies in healthy subjects aimed at assessing the impact of CYP3A and P-gp inhibitors, CYP3A inducers and acid-reducing agents (ARAs) on the pharmacokinetics (PK) of asciminib (single dose of 40 mg). Asciminib exposure (area under the curve [AUC]) unexpectedly decreased by ~40% when administered concomitantly with the strong CYP3A inhibitor itraconazole oral solution, whereas maximum plasma concentration (Cmax ) decreased by ~50%. However, asciminib exposure was slightly increased in subjects receiving an itraconazole capsule (~3%) or clarithromycin (~35%), another strong CYP3A inhibitor. Macroflux studies showed that cyclodextrin (present in high quantities as excipient [40-fold excess to itraconazole] in the oral solution formulation of itraconazole) decreased asciminib flux through a lipid membrane by ~80%. The AUC of asciminib was marginally decreased by concomitant administration with the strong CYP3A inducer rifampicin (by ~13-15%) and the strong P-gp inhibitor quinidine (by ~13-16%). Concomitant administration of the ARA rabeprazole had little or no effect on asciminib AUC, with a 9% decrease in Cmax . The treatments were generally well tolerated. Taking into account the large therapeutic window of asciminib, the observed changes in asciminib PK following multiple doses of P-gp, CYP3A inhibitors, CYP3A inducers, or ARAs are not considered to be clinically meaningful. Care should be exercised when administering asciminib concomitantly with cyclodextrin-containing drug formulations.

Design & development of customizable web API for interoperability of antimicrobial resistance data.

Antimicrobial resistance (AMR) is a global health emergency. Complementary to developing new drugs, AMR can be monitored and controlled through cost-effective active surveillance of resistance. As an initiative to monitor resistance, countries all across the globe are collecting data using a variety of surveillance tools. Moreover, hospitals routinely collect the AMR data for treatment which is being stored in their Laboratory and Hospital Information systems (LIS-HIS). The generated clinical data is collected & stored in various formats, making it very difficult to analyze and generate national reports. To integrate the stored clinical data for predictive modeling and analysis, there is an immediate need for a one-stop data repository capable of importing and exporting data in simple data exchange formats (CSV/Excel). The paper highlights the design & development of i-DIA, a python-based web API to facilitate the interoperability of AMR data by automatically importing the bulk of medical data from CSV files into generic data management and analysis system. The i-DIA has been integrated and tested with the ICMR's AMR surveillance network on in-house developed software, i-AMRSS. The i-AMRSS is presently collecting data from 31 laboratories across India and i-DIA has been used to import data generated from LIS & HIS of a few hospitals directly into the system. The paper also proposes the complete web-based framework (an extension of i-DIA) integrated with peer-to-peer system architecture.

Pharmacokinetics and safety of capmatinib with food in patients with MET-dysregulated advanced solid tumors.

PURPOSE: In the Phase II GEOMETRY mono-1 study, the potent and selective mesenchymal-epithelial transition (MET) inhibitor capmatinib exhibited considerable efficacy in MET exon 14 skipping (METex14)-mutated metastatic non-small cell lung cancer at a dose of 400 mg BID. The current recommended dose is 400 mg BID in tablet formulation, with or without food. This article reports the pharmacokinetic (PK) profile, safety, and tolerability of capmatinib 300 and 400 mg BID given with food in MET-dysregulated advanced solid tumors. METHODS: This multicenter, open-label, Phase I study enrolled adult patients with MET-dysregulated advanced solid tumors. In the dose escalation phase, capmatinib tablets were orally administered at a dose of 300 mg BID with food; if tolerated, the dose escalation cohort of 400 mg BID was to be opened to enrollment. In the expansion phase, patients were to be enrolled at the higher of the tolerated doses. Tablets were taken within 30 minutes of an unrestricted meal type, except on cycle 1 day 1 (C1D1) and cycle 1 day 7 (C1D7), when they were given with a high-fat meal. The primary objectives were to determine the higher of the tolerated study doses and assess PK variables, with a secondary objective of safety. FINDINGS: Overall, 35 patients (300 mg BID, n = 8; 400 mg BID, n = 27) with MET-dysregulated advanced solid tumors were enrolled; all patients had received prior antineoplastic therapy, and the most common primary site was lung (45.7%). Among PK-evaluable patients, the median Tmax for capmatinib after administration with a high-fat meal (on C1D1/C1D7) was 4.0 to 5.6 hours across doses. At steady state (C1D7), capmatinib accumulation was low across dose levels (geometric mean of accumulation ratios, 1.29-1.69), with an increase in exposure (AUCtau and Cmax) from 300 to 400 mg BID. There were no occurrences of dose-limiting toxicity. All patients experienced at least 1 adverse event, and treatment-related adverse events occurred in 28 patients (80%; 300 mg BID, n = 6; 400 mg BID, n = 22), the most frequent of which were fatigue (37.1%) and nausea (34.3%). IMPLICATIONS: Capmatinib tablet formulation at a dose of up to 400 mg BID with food is well tolerated in patients with MET-dysregulated advanced solid tumors, with safety observations consistent with the existing profile under fasted conditions. These findings support the capmatinib dosing recommendation of 400 mg BID with or without food. ClinicalTrials.gov identifier: NCT02925104.

Intravenous infusion tests have limited utility for selecting long-term drug therapy in patients with chronic pain: a systematic review.

Since the first description in the early 1990s, the scope of intravenous infusions tests has expanded to encompass multiple drug classes and indications. Purported advantages of these tests include elucidating mechanisms of pain, providing temporary relief of symptoms, and usefulness as prognostic tools in guiding drug therapy. In an attempt to discern the value of these tests, the authors conducted a systematic review to explore the rationale and evidence behind the following intravenous infusion tests: lidocaine, ketamine, opioid, and phentolamine. The studies evaluating all intravenous infusion tests were characterized by lack of standardization, wide variations in outcome measures, and methodological flaws. The strongest evidence found was for the intravenous lidocaine test, with the phentolamine test characterized by the least convincing data. Whereas intravenous opioid infusions are the most conceptually appealing test, their greatest utility may be in predicting poor responders to sustained-release formulations.

A genome-wide map of circular RNAs in adult zebrafish.

Circular RNAs (circRNAs) are transcript isoforms generated by back-splicing of exons and circularisation of the transcript. Recent genome-wide maps created for circular RNAs in humans and other model organisms have motivated us to explore the repertoire of circular RNAs in zebrafish, a popular model organism. We generated RNA-seq data for five major zebrafish tissues - Blood, Brain, Heart, Gills and Muscle. The repertoire RNA sequence reads left over after reference mapping to linear transcripts were used to identify unique back-spliced exons utilizing a split-mapping algorithm. Our analysis revealed 3,428 novel circRNAs in zebrafish. Further in-depth analysis suggested that majority of the circRNAs were derived from previously well-annotated protein-coding and long noncoding RNA gene loci. In addition, many of the circular RNAs showed extensive tissue specificity. We independently validated a subset of circRNAs using polymerase chain reaction (PCR) and divergent set of primers. Expression analysis using quantitative real time PCR recapitulate selected tissue specificity in the candidates studied. This study provides a comprehensive genome-wide map of circular RNAs in zebrafish tissues.

Chamber Specific Gene Expression Landscape of the Zebrafish Heart.

The organization of structure and function of cardiac chambers in vertebrates is defined by chamber-specific distinct gene expression. This peculiarity and uniqueness of the genetic signatures demonstrates functional resolution attributed to the different chambers of the heart. Altered expression of the cardiac chamber genes can lead to individual chamber related dysfunctions and disease patho-physiologies. Information on transcriptional repertoire of cardiac compartments is important to understand the spectrum of chamber specific anomalies. We have carried out a genome wide transcriptome profiling study of the three cardiac chambers in the zebrafish heart using RNA sequencing. We have captured the gene expression patterns of 13,396 protein coding genes in the three cardiac chambers-atrium, ventricle and bulbus arteriosus. Of these, 7,260 known protein coding genes are highly expressed (≥10 FPKM) in the zebrafish heart. Thus, this study represents nearly an all-inclusive information on the zebrafish cardiac transcriptome. In this study, a total of 96 differentially expressed genes across the three cardiac chambers in zebrafish were identified. The atrium, ventricle and bulbus arteriosus displayed 20, 32 and 44 uniquely expressing genes respectively. We validated the expression of predicted chamber-restricted genes using independent semi-quantitative and qualitative experimental techniques. In addition, we identified 23 putative novel protein coding genes that are specifically restricted to the ventricle and not in the atrium or bulbus arteriosus. In our knowledge, these 23 novel genes have either not been investigated in detail or are sparsely studied. The transcriptome identified in this study includes 68 differentially expressing zebrafish cardiac chamber genes that have a human ortholog. We also carried out spatiotemporal gene expression profiling of the 96 differentially expressed genes throughout the three cardiac chambers in 11 developmental stages and 6 tissue types of zebrafish. We hypothesize that clustering the differentially expressed genes with both known and unknown functions will deliver detailed insights on fundamental gene networks that are important for the development and specification of the cardiac chambers. It is also postulated that this transcriptome atlas will help utilize zebrafish in a better way as a model for studying cardiac development and to explore functional role of gene networks in cardiac disease pathogenesis.

zflncRNApedia: A Comprehensive Online Resource for Zebrafish Long Non-Coding RNAs.

Recent transcriptome annotation using deep sequencing approaches have annotated a large number of long non-coding RNAs in zebrafish, a popular model organism for human diseases. These studies characterized lncRNAs in critical developmental stages as well as adult tissues. Each of the studies has uncovered a distinct set of lncRNAs, with minor overlaps. The availability of the raw RNA-Seq datasets in public domain encompassing critical developmental time-points and adult tissues provides us with a unique opportunity to understand the spatiotemporal expression patterns of lncRNAs. In the present report, we created a catalog of lncRNAs in zebrafish, derived largely from the three annotation sets, as well as manual curation of literature to compile a total of 2,267 lncRNA transcripts in zebrafish. The lncRNAs were further classified based on the genomic context and relationship with protein coding gene neighbors into 4 categories. Analysis revealed a total of 86 intronic, 309 promoter associated, 485 overlapping and 1,386 lincRNAs. We created a comprehensive resource which houses the annotation of lncRNAs as well as associated information including expression levels, promoter epigenetic marks, genomic variants and retroviral insertion mutants. The resource also hosts a genome browser where the datasets could be browsed in the genome context. To the best of our knowledge, this is the first comprehensive resource providing a unified catalog of lncRNAs in zebrafish. The resource is freely available at URL: http://genome.igib.res.in/zflncRNApedia.

Short stories on zebrafish long noncoding RNAs.

The recent re-annotation of the transcriptome of human and other model organisms, using next-generation sequencing approaches, has unravelled a hitherto unknown repertoire of transcripts that do not have a potential to code for proteins. These transcripts have been largely classified into an amorphous class popularly known as long noncoding RNAs (lncRNA). This discovery of lncRNAs in human and other model systems have added a new layer to the understanding of gene regulation at the transcriptional and post-transcriptional levels. In recent years, three independent studies have discovered a number of lncRNAs expressed in different stages of zebrafish development and adult tissues using a high-throughput RNA sequencing approach, significantly adding to the repertoire of genes known in zebrafish. A subset of these transcripts also shows distinct and specific spatiotemporal patterns of gene expression, pointing to a tight regulatory control and potential functional roles in development, organogenesis, and/ or homeostasis. This review provides an overview of the lncRNAs in zebrafish and discusses how their discovery could provide new insights into understanding biology, explaining mutant phenotypes, and helping in potentially modeling disease processes.