BLM helicase unwinds lagging strand substrates to assemble the ALT telomere damage response.

The Bloom syndrome (BLM) helicase is critical for alternative lengthening of telomeres (ALT), a homology-directed repair (HDR)-mediated telomere maintenance mechanism that is prevalent in cancers of mesenchymal origin. The DNA substrates that BLM engages to direct telomere recombination during ALT remain unknown. Here, we determine that BLM helicase acts on lagging strand telomere intermediates that occur specifically in ALT-positive cells to assemble a replication-associated DNA damage response. Loss of ATRX was permissive for BLM localization to ALT telomeres in S and G2, commensurate with the appearance of telomere C-strand-specific single-stranded DNA (ssDNA). DNA2 nuclease deficiency increased 5'-flap formation in a BLM-dependent manner, while telomere C-strand, but not G-strand, nicks promoted ALT. These findings define the seminal events in the ALT DNA damage response, linking aberrant telomeric lagging strand DNA replication with a BLM-directed HDR mechanism that sustains telomere length in a subset of human cancers.

The U- advancement Burrow's Flap in Persistent Tracheocutaneous Fistula. ~ Case Report.

Persistent tracheo-cutaneous fistulae necessitate a closure with pedicled or free flaps. The modality adopted is to reconstitute the anterior tracheal wall without compromising the tracheal lumen. We have developed the lateral U advancement Burrow's flap over the strap muscles and tracheal lateral fibrous flaps, to repair a large trachea-cutaneous fistula.

Structural-Based Virtual Screening of FDA-Approved Drugs Repository for NSP16 Inhibitors, Essential for SARS-COV-2 Invasion Into Host Cells: Elucidation From MM/PBSA Calculation.

NSP16 is one of the structural proteins of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) necessary for its entrance to the host cells. It exhibits 2'O-methyl-transferase (2'O-MTase) activity of NSP16 using methyl group from S-adenosyl methionine (SAM) by methylating the 5-end of virally encoded mRNAs and shields viral RNA, and also controls its replication as well as infection. In the present study, we used in silico approaches of drug repurposing to target and inhibit the SAM binding site in NSP16 using Food and Drug Administration (FDA)-approved small molecules set from Drug Bank database. Among the 2 456 FDA-approved molecules, framycetin, paromomycin, and amikacin were found to be significant binders against the SAM binding cryptic pocket of NSP16 with docking score of -13.708, -14.997 and -15.841 kcal/mol, respectively. Classical molecular dynamics (MD) simulation and molecular mechanics Poisson-Boltzmann surface area (MM/PBSA)-based binding free energy calculation depicted that all these three framycetin, paromomycin, and amikacin might be promising therapeutic leads towards SARS-CoV-2 infections via host immune escape inhibition pathway.

A systematic review on antimicrobial activities of green synthesised Selaginella silver nanoparticles.

BACKGROUND: Metallic nanoparticles from different natural sources exhibit superior therapeutic options as compared to the conventional methods. Selaginella species have attracted special attention of researchers worldwide due to the presence of bioactive molecules such as flavonoids, biflavonoids, triterpenes, steroids, saponins, tannins and other secondary metabolites that exhibit antimicrobial, antiplasmodial, anticancer and anti-inflammatory activities. Environment friendly green synthesised silver nanoparticles from Selaginella species provide viable, safe and efficient treatment against different fungal pathogens. OBJECTIVE: This systematic review aims to summarise the literature pertaining to superior antifungal ability of green synthesised silver nanoparticles using plant extracts of Selaginella spp. in comparison to both aqueous and ethanolic raw plant extracts by electronically collecting articles from databases. METHODS: The recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis were taken into consideration while preparing this review. The titles and abstracts of the collected data were stored in Endnote20 based on the inclusion and exclusion criteria. The search strategy included literature from established sources like PubMed, Google Scholar and Retrieval System Online using subject descriptors. RESULTS: The search yielded 60 articles with unique hits. After removal of duplications, 46 articles were identified, 40 were assessed and only seven articles were chosen and included in this review based on our eligibility criteria. CONCLUSION: The physicochemical and preliminary phytochemical investigations of Selaginella suggest higher drug potency of nanoparticles synthesised from plant extract against different diseases as compared to aqueous and ethanolic plant extracts. The study holds great promise as the synthesis of nanoparticles involves low energy consumption, minimal technology and least toxic effects.

Structural insights into BCDX2 complex function in homologous recombination.

Homologous recombination (HR) fulfils a pivotal role in the repair of DNA double-strand breaks and collapsed replication forks1. HR depends on the products of several paralogues of RAD51, including the tetrameric complex of RAD51B, RAD51C, RAD51D and XRCC2 (BCDX2)2. BCDX2 functions as a mediator of nucleoprotein filament assembly by RAD51 and single-stranded DNA (ssDNA) during HR, but its mechanism remains undefined. Here we report cryogenic electron microscopy reconstructions of human BCDX2 in apo and ssDNA-bound states. The structures reveal how the amino-terminal domains of RAD51B, RAD51C and RAD51D participate in inter-subunit interactions that underpin complex formation and ssDNA-binding specificity. Single-molecule DNA curtain analysis yields insights into how BCDX2 enhances RAD51-ssDNA nucleoprotein filament assembly. Moreover, our cryogenic electron microscopy and functional analyses explain how RAD51C alterations found in patients with cancer3-6 inactivate DNA binding and the HR mediator activity of BCDX2. Our findings shed light on the role of BCDX2 in HR and provide a foundation for understanding how pathogenic alterations in BCDX2 impact genome repair.

Mechanistic investigation of formation of highly-dispersed silver nanoparticles using sea buckthorn extract.

Nowadays, the greener pathways for the synthesis of nanostructures are being explored. The extracts of different parts of plantsvizleaves, stems, and roots have been investigated. However, these extracts have been prepared by simply boiling or microwaving, or sonicating the parts of plants with water. Therefore, to have deeper insight and to investigate the full potential of plant extracts, serial extraction of leaves of sea buckthorn (Hippophae rhamnoides L.) which is a medicinally important plant was attempted using the soxhlet apparatus. The as-obtained polyphenolic-rich extract was employed for the preparation of silver nanoparticles (Ag-NPs). Under optimized reaction conditionsviz60 °C temperature and 500µl of extract solution (5 mg ml-1) highly disperse spherical nanoparticles of the average size of 15.8 ± 4.8 nm were obtained. Further, the optical band gap of Ag-NPs prepared using optimized reaction conditions was found to be 2.6 eV using the Tauc equation. Additionally, to understand the reduction by the extract, kinetic studies were also carried out which suggest the predominant occurrence of pseudo-first-order reaction. Furthermore, the mechanism of formation of Ag-NPs using major components of extractvizgallic acid and catechin which were identified by HPLC were also investigated using DFT. The mechanistic investigation was performed for both the keto-enol and radical-mediated preparation of Ag-NPs. Such theoretical investigations will help in the efficient designing of greener and novel routes for the synthesis of Ag-NPs. Additionally, the prepared silver was also employed for the colorimetric detection of H2O2.

Oral Atenolol versus Propranolol in the Treatment of Infantile Hemangioma: A Systematic Review and Meta-Analysis.

Background: Infantile hemangioma (IH) is the most common benign vascular tumor of infancy. Propranolol is considered first-line therapy for IH. However, it is associated with side effects. Therefore, there was a need for alternative therapy. Atenolol, a selective b1-blocker may be free from such side effects. Hence, the present study aims to develop a more accurate estimate of the safety and efficacy of atenolol compared to propranolol in the treatment of IH. Methodology: A search of various literature databases (PubMed, Embase, Ovid, Scopus, Cochrane Central, CINAHL, Web of Science, and Google Scholar) was done to identify studies which compared propranolol versus atenolol in the treatment of IH. The combined odds ratio along with corresponding 95% confidence intervals (CIs) were evaluated using a fixed-effects model. Results: A total of 300 articles were screened of which five studies including 116 patients in atenolol arm and 138 patients in the propranolol arm were analyzed. Atenolol was comparable to propranolol in terms of efficacy as no significant difference was seen between both the treatment arms in terms of hemangioma activity score (mean difference 0.25 [95% CI;‒0.21, 0.71]) and complete response (odds ratio [OR] =0.43; 95% CI; 0.17, 1.11; P = 0.08,). Atenolol therapy was better than propranolol in terms of safety, i.e., serious/potentially serious side effect, (OR = 0.11; 95% CI; 0.02, 0.51; P = 0.005) and wheezing/bronchial hyperreactivity (OR = 0.11; 95% CI; 0.02, 0.51; P = 0.005). Conclusion: The present meta-analysis provides evidence that atenolol has got a comparable efficacy and better safety profile with propranolol.

Yogic Neti-Kriya Using Povidone Iodine: Can it have a Preventive Role Against SARS-CoV-2 Infection Gateway?

During this COVID-19 pandemic, except steroid, none of the therapeutic measures have showed any evidence of efficacy. Traditionally jala-neti using lukewarm salted water remains a yogic way of maintaining upper airway hygiene. Saline irrigation decreases the concentration of inflammatory mediators (e.g. histamine, leukotriene etc.) in nasal secretions, reduces the severity and frequency of sinusitis, reduce need of antibiotic therapy and restores competency of nasal mucosa. Jala-neti is an integral part of six cleansing techniques of yogic kriyas practised in India since thousands of years. Jala-neti can clean the upper airways, prevents colonization of infectious agents, removes foreign bodies, prevents stasis of mucous and subsequently enhances the drainage of paranasal sinuses and maintain health. Regular practice of Jala neti improves nasal symptoms and overall health status of patients with sinusitis. Jala-neti sample can even be used for COVID-19 diagnosis. Povidone iodine (PVP-I) has been utilized as a time tested antimicrobial agent with broad spectrum coverage against wide range of bacteria and viruses. Anti-SARS-CoV-2 action of PVP-I was seen at a concentration as low as 0.45%. PVP-I is generally well tolerated upto 5%, however nasal ciliotoxicity is reported at this concentration, however, this toxicity is not reported with lower concentrations(1.25% and 0.5%). So, theoretically, by using neti-kriya with povidone iodine (0.5-1%) as irrigation solution can combine and enhance the protection against COVID-19 and this can be an important armor in the fight against COVID-19. However, this hypothesis needs to be validated in real life clinical trial scenario before implementing.

Predictors of mortality in children with cystic fibrosis in India.

BACKGROUND: There is a lack of studies on cystic fibrosis (CF) outcomes in children from developing countries like India. Identifying risk factors for mortality may help identify the high-risk group and plan policy management of such patients. We aimed to determine the factors associated with mortality among Indian children with CF. METHODS: In this retrospective study, we extracted demography, clinical features, laboratory and outcome data from medical records of children with CF. Bivariate and multivariate analysis was performed to identify variables associated with mortality. RESULTS: We enrolled 178 children, and there were 32 (18.0%) deaths. Median (IQR) z-score for body mass index (BMI) at last follow up was -1.5 (-2.7, -0.2) and -2.5 (-4.0, -1.6), p-value 0.039, in survived and deceased group respectively. Mean (SD) of % predicted of FEV1/FVC and FEV1 25-75 at the time of diagnosis in survived versus diseased group was 94.7 (24.1) versus 81.5 (19.1), p-value 0.063 and 56.1 (38.9) versus 45.7 (29.9), p-value 0.347, respectively. Significant factors associated with mortality included history of neonatal complications; hazard ratio (HR): 8.5 (95% confidence interval [CI]: 3.0-23.9, p < 0.001), low Z-scores for BMI at the time of diagnosis; HR: 7.1 (95% CI: 2.3-22.0, p < 0.001), FEV1/FVC at the time of diagnosis; HR: 5.1 (95% CI: 1.65-15.4, p < 0.004), and FEV1 25-75; HR: 3.6 (95% CI: 1.1-11.8, p = 0.03). CONCLUSIONS: Factors associated with increased mortality risk included neonatal complications, low BMI, and lower pulmonary function test results. Low BMI and low PFT indices can be improved upon by timely treatment of respiratory infections, better nutrition, early diagnosis, and treatment. A newborn screening program may help in early diagnosis and identification of the neonatal problem of CF.

Clinically relevant cell culture models and their significance in isolation, pathogenesis, vaccine development, repurposing and screening of new drugs for SARS-CoV-2: a systematic review.

BACKGROUND: In-Vitro/Cellular evidence is the backbone and vital proof of concept during the development of novel therapeutics as well as drugs repurposing against COVID-19. Choosing an ideal in-vitro model is vital as the virus entry is through ACE2, CD147, and TMPRSS2 dependant and very specific. In this regard, this is the first systematic review addressing the importance of specific cell lines used as potential in-vitro models in the isolation, pathogenesis, and therapeutics for SARS-COV-2. METHODS: We searched 17 literature databases with appropriate keywords, and identified 1173 non-duplicate studies. In the present study, 71 articles are included after a careful, thorough screening of the titles and their abstracts for possible inclusion using predefined inclusion/exclusion criteria (PRISMA Guidelines). RESULTS: In the current study, we compiled cell culture-based studies for SARS-CoV-2 and found the best compatible In-Vitro models for SARS-CoV-2 (Vero, VeroE6, HEK293 as well as its variants, Huh-7, Calu-3 2B4, and Caco2). Among other essential cell lines used include LLC-MK2, MDCKII, BHK-21, HepG2, A549,T cell leukemia (MT-2), stems cells based cell line DYR0100for differentiation assays, and embryo-specific NIH3T3 cell line for vaccine production. CONCLUSION: The Present study provides a detailed summary of all the drugs/compounds screened for drug repurposing and discovery purpose using the in-vitro models for SARS-CoV-2 along with isolation, pathogenesis and vaccine production. This study also suggests that after careful evaluation of all the cell line based studies, Kidney cells (VeroE6, HEK293 along with their clones), liver Huh-7cells, respiratory Calu-3 cells, and intestinal Caco-2 are the most widely used in-vitro models for SARS-CoV-2.

Efficacy of green tea, its polyphenols and nanoformulation in experimental colitis and the role of non-canonical and canonical nuclear factor kappa beta (NF-kB) pathway: a preclinical in-vivo and in-silico exploratory study.

NF-kB plays a major role in the aetiopathogenesis of inflammatory-colitis. In this study, we evaluated the efficacy of green tea and its polyphenols and their nanoformulation in Tri-Nitro Benzene Sulfonic acid (TNBS) induced colitis in in-vivo system (Rat) and the involvement of non-canonical and canonical NF-kB pathway in green tea mediated protection (in-silico platform). We used the Wister rat model of TNBS-induced colitis. Rats were grouped into eleven groups (six animals each) and administered vehicle (ethanol), TNBS, Epicatechin (EC), Epigallocatechin (EGC), Epicatechin-gallate (ECG), Epigallocatechin-gallate (EGCG), sulfasalazine, green tea, EGCG + sulfasalazine, nano-EGCG and nano-EGCG + sulfasalazine for 14 days after induction of colitis. Colonic tissue was evaluated for the level of malondialdehyde, myeloperoxidase activity, catalase, reduced glutathione, glutathione peroxidase, IL-6, TNF-α, IL-1ß, NF-κB and morphological and histopathological evidence of damage. In the in-silico part, molecular docking and dynamic simulation study of EGCG was done against different targets in NF-kB for detailed evaluation of the role of non-canonical and canonical NF-KB pathway. In our study, EGCG reduced colonic inflammation, markers of oxidative stress, TNF-α, NF-κB, IL-1ß and IL-6. Nano-EGCG + sulfasalazine was more efficacious when compared to EGCG + sulfasalazine. In molecular docking and molecular dynamic simulation studies, EGCG showed a good binding profile to the inhibitor binding sites of IKK-beta, IKK-alpha and NIK. Thus, it can be concluded that EGCG showed protective action in experimental colitis acting through both non-canonical and canonical NF-kB pathway. Nano-EGCG + sulfasalazine combination showed better protection than nano-EGCG alone. Communicated by Ramaswamy H. Sarma.

Efficacy and Safety of Topical Cysteamine in Corneal Cystinosis: A Systematic Review and Meta-Analysis.

PURPOSE: To evaluate safety and efficacy of topical cysteamine ophthalmic solution for corneal cystinosis. METHODS: Seven databases were searched (PubMed, OVID, EMBASE, Web of Science, Cochrane Central, Google Scholar, and ClinicalTrials.gov) for relevant studies, using appropriate keywords. Comparative observational studies and randomized controlled trials comparing cysteamine with control or other formulations for treatment of corneal or ophthalmic cystinosis were included. Outcome measurements were improvement or response to therapy, change in corneal cystine crystal score (CCCS), in vivo confocal microscopy score (IVCM), cystine crystal depth, contrast sensitivity (CS), photophobia score, and safety. DESIGN: Systematic review and meta-analysis. RESULTS: Seven studies were included. Compared to placebo and control, the cysteamine arm was better in terms of improvements and responses to therapy (2 studies showed a risk ratio [RR] of 16; 95% confidence interval [CI]: 2.30-111.37) and crystal density score (1 study showed a mean difference [MD] of -0.80; 95% CI: -1.56 to -0.04). No significant differences were observed in terms of improvement in CS (1 study showed an RR of 7.00; 95% CI: 0.47-103.27). Compared to cystamine, cysteamine showed benefits in terms of crystal density score (MD -0.94; 95% CI: -1.64 to -0.24). Compared to a newer formulation, the standard formulation (cysteamine [Cystaran]; 0.55% cysteamine hydrochloride + benzalkonium chloride 0.01%) performed better in terms of decreasing CCCS. Another newer, viscous formulation, Cystadrops, performed better than the standard formulation in terms of change in CCCS, IVCM score, corneal crystal depth, and photophobia score; however, local adverse effects and blurring were higher in the group receiving Cystadrops. CONCLUSIONS: Conventional cysteamine (0.1% to 0.3%) performed better than placebo (control) in terms of response to therapy. In terms of decreasing corneal cystine density, cysteamine (0.55%) was better than cystamine (0.55%), and the viscous Cystadrops (0.55%) was better than the standard formulation (0.1%).

Virtual screening and molecular dynamics study of approved drugs as inhibitors of spike protein S1 domain and ACE2 interaction in SARS-CoV-2.

BACKGROUND: The receptor binding domain (RBD) of spike protein S1 domain SARS-CoV-2 plays a key role in the interaction with ACE2, which leads to subsequent S2 domain mediated membrane fusion and incorporation of viral RNA into host cells. In this study we tend to repurpose already approved drugs as inhibitors of the interaction between S1-RBD and the ACE2 receptor. METHODS: 2456 approved drugs were screened against the RBD of S1 protein of SARS-CoV-2 (target PDB ID: 6M17). As the interacting surface between S1-RBD and ACE2 comprises of bigger region, the interacting surface was divided into 3 sites on the basis of interactions (site 1, 2 and 3) and a total of 5 grids were generated (site 1, site 2, site 3, site 1+site 2 and site 2+site 3). A virtual screening was performed using GLIDE implementing HTVS, SP and XP screening. The top hits (on the basis of docking score) were further screened for MM-GBSA. All the top hits were further evaluated in molecular dynamics studies. Performance of the virtual screening protocol was evaluated using enrichment studies. RESULT: and discussion: We performed 5 virtual screening against 5 grids generated. A total of 42 compounds were identified after virtual screening. These drugs were further assessed for their interaction dynamics in molecular dynamics simulation. On the basis of molecular dynamics studies, we come up with 10 molecules with favourable interaction profile, which also interacted with physiologically important residues (residues taking part in the interaction between S1-RBD and ACE2. These are antidiabetic (acarbose), vitamins (riboflavin and levomefolic acid), anti-platelet agents (cangrelor), aminoglycoside antibiotics (Kanamycin, amikacin) bronchodilator (fenoterol), immunomodulator (lamivudine), and anti-neoplastic agents (mitoxantrone and vidarabine). However, while considering the relative side chain fluctuations when compared to the S1-RBD: ACE2 complex riboflavin, fenoterol, cangrelor and vidarabine emerged out as molecules with prolonged relative stability. CONCLUSION: We identified 4 already approved drugs (riboflavin, fenoterol, cangrelor and vidarabine) as possible agents for repurposing as inhibitors of S1:ACE2 interaction. In-vitro validation of these findings are necessary for identification of a safe and effective inhibitor of S1: ACE2 mediated entry of SARS-CoV-2 into the host cell.

Premature graying of hair: Risk factors, co-morbid conditions, pharmacotherapy and reversal-A systematic review and meta-analysis.

Premature graying of hair (PGH) being a very common entity for which pharmacotherapy and reversibility are not properly addressed. Therefore, this systematic review was conducted to address these issues. For this relevant study were selected from various databases including PubMed, EMBASE, OVID, Web of science, Scopus, and Google Scholar till January 20, 2019. Studies which reported risk factors, co-morbid conditions associated with PGH, its pharmacotherapy and reversal were included in the study. Although many risk factors are reported in literature, smoking, vitamin deficiency (B12, folic acid, and B7), mineral deficiency (low serum calcium and serum ferritin) are found to be associated with PGH. Other important risk factors are family history of PGH, obesity, high B.P, lack of exercise, drugs, genetic syndromes, dyslipidemia, thyroid disorders, hyperuricemia, and alteration in liver function. PGH is found to be an important marker of CAD, more so in case of smoker. Among different pharmacotherapeutic management options, low grade recommendation (2A) is given to calcium pantothenate, PABA, calcium pantothenate + PABA combination. Anu-tailam is the only herbal agent evaluated in clinical research settings. Finally, treating the accompanying pathologies led to the reversal of the disease in many cases.

Specificity of end resection pathways for double-strand break regions containing ribonucleotides and base lesions.

DNA double-strand break repair by homologous recombination begins with nucleolytic resection of the 5' DNA strand at the break ends. Long-range resection is catalyzed by EXO1 and BLM-DNA2, which likely have to navigate through ribonucleotides and damaged bases. Here, we show that a short stretch of ribonucleotides at the 5' terminus stimulates resection by EXO1. Ribonucleotides within a 5' flap are resistant to cleavage by DNA2, and extended RNA:DNA hybrids inhibit both strand separation by BLM and resection by EXO1. Moreover, 8-oxo-guanine impedes EXO1 but enhances resection by BLM-DNA2, and an apurinic/apyrimidinic site stimulates resection by BLM-DNA2 and DNA strand unwinding by BLM. Accordingly, depletion of OGG1 or APE1 leads to greater dependence of DNA resection on DNA2. Importantly, RNase H2A deficiency impairs resection overall, which we attribute to the accumulation of long RNA:DNA hybrids at DNA ends. Our results help explain why eukaryotic cells possess multiple resection nucleases.

Therapeutic options for management of Hori's nevus: A systematic review.

Hori's nevus is a pigmentation disorder reported mainly in middle-aged Asian women. There is no systematic review addressing its pharmacotherapy. The population for our systematic review was patients with a clinical/histological diagnosis of Hori's nevus (both sex, any age group). We screened five literature databases using relevant keywords. All RCTs, observational studies and case series mentioning at least one intervention and outcome of that intervention were included. Nineteen studies were included in the final systematic review from total 680 identified nonduplicate records. Different forms of laser (alexandrite laser [QSAL and PSAL], Nd:YAG laser [QSNYL high fluence, low fluence, 532 followed by 1064 nm], Er: YAG and Nd:YAG combination, ruby laser [QSRL], CO2 laser followed by QSRL) and dermabrasion were found to be useful in treatment of Hori' nevus. Among alexandrite lasers, PSAL is more efficacious and safe than QSAL. In case of high fluence QSNYL, hyperpigmentation rate is quite high while low fluence QSNYL requires more number of treatment sessions. The combined 1064 nm + 532 nm protocol is better in terms of efficacy and safety. Er:YAG + Nd:YAG combination have similar efficacy and added advantage of synergistic action and no adverse event.

Bio-analytical applications of nicking endonucleases assisted signal-amplification strategies for detection of cancer biomarkers -DNA methyl transferase and microRNA.

The low concentrations of cancer biomarkers in the blood have limited the utility of quantitative bioassays developed for the purpose. The advent of nicking endonucleases (NEases) as signal amplification tools have greatly enhanced the detection efficiency and provided a multi-optional platform to design target specific detection methods. The present review focuses on the prominent features of NEases, modified DNA probes (such as hairpin (HP) probes, molecular beacons, and G- quadruplex) that mediate cyclic cascade and role of helper enzymes. Application of NEase assisted signal amplification (NESA) has been discussed for diagnosis of two prominent cancer biomarkers viz. DNA methyl transferase (Dam MTase) and microRNA (miRNA). NESA mediated techniques such as rolling circle amplification (RCA), strand displacement amplification (SDA) and isothermal exponential amplification (EXPAR), have been compared in light of their future applications in clinical diagnosis. Significance of nanomaterials to achieve further amplification and NESA assays for simultaneous detection of miRNAs has also been conversed. It is anticipated that the information gained from the analyses of the prospects and limitations of NESA-based assays will be useful towards understanding the applications, and improvement of efficient isothermal exponential amplification strategies for highly sensitive and selective detection of cancer biomarkers.

An Improved Tobacco Mosaic Virus (TMV)-Conjugated Multiantigen Subunit Vaccine Against Respiratory Tularemia.

Francisella tularensis, the causative agent of the fatal human disease known as tularemia is classified as a Category A Select Agent by the Centers for Disease Control. No licensed vaccine is currently available for prevention of tularemia in the United States. Previously, we published that a tri-antigen tobacco mosaic virus (TMV) vaccine confers 50% protection in immunized mice against respiratory tularemia caused by F. tularensis. In this study, we refined the TMV-vaccine formulation to improve the level of protection in immunized C57BL/6 mice against respiratory tularemia. We developed a tetra-antigen vaccine by conjugating OmpA, DnaK, Tul4, and SucB proteins of Francisella to TMV. CpG was also included in the vaccine formulation as an adjuvant. Primary intranasal (i.n.) immunization followed by two booster immunizations with the tetra-antigen TMV vaccine protected 100% mice against i.n. 10LD100 challenges dose of F. tularensis live vaccine strain (LVS). Mice receiving three immunization doses of tetra-antigen TMV vaccine showed only transient body weight loss, cleared the infection rapidly, and showed minimal histopathological lesions in lungs, liver, and spleen following a lethal respiratory challenge with F. tularensis LVS. Mice immunized with the tetra-antigen TMV vaccine also induced strong ex vivo recall responses and were protected against a lethal challenge as late as 163 days post-primary immunization. Three immunization with the tetra-antigen TMV vaccine also induced a stronger humoral immune response predominated by IgG1, IgG2b, and IgG2c antibodies than mice receiving only a single or two immunizations. Remarkably, a single dose protected 40% of mice, while two doses protected 80% of mice from lethal pathogen challenge. Immunization of Interferon-gamma (IFN-γ)-deficient mice with the tetra-antigen TMV vaccine demonstrated an absolute requirement of IFN-γ for the generation of protective immune response against a lethal respiratory challenge with F. tularensis LVS. Collectively, this study further demonstrates the feasibility of TMV as an efficient platform for the delivery of multiple F. tularensis antigens and that tetra-antigen TMV vaccine formulation provides complete protection, and induces long-lasting protective and memory immune responses against respiratory tularemia caused by F. tularensis LVS.

Intranasal administration of a two-dose adjuvanted multi-antigen TMV-subunit conjugate vaccine fully protects mice against Francisella tularensis LVS challenge.

Tularemia is a fatal human disease caused by Francisella tularensis, a Gram-negative encapsulated coccobacillus bacterium. Due to its low infectious dose, ease of aerosolized transmission, and lethal effects, the CDC lists F. tularensis as a Category A pathogen, the highest level for a potential biothreat agent. Previous vaccine studies have been conducted with live attenuated, inactivated, and subunit vaccines, which have achieved partial or full protection from F. tularensis live vaccine strain (LVS) challenge, but no vaccine has been approved for human use. We demonstrate the improved efficacy of a multi-antigen subunit vaccine by using Tobacco Mosaic virus (TMV) as an antigen carrier for the F. tularensis SchuS4 proteins DnaK, OmpA, SucB and Tul4 (DOST). The magnitude and quality of immune responses were compared after mice were immunized by subcutaneous or intranasal routes of administration with a TMV-DOST mixture, with or without four different adjuvants. Immune responses varied in magnitude and isotype profile, by antigen, by route of administration, and by protection in an F. tularensis LVS challenge model of disease. Interestingly, our analysis demonstrates an overwhelming IgG2 response to SucB after intranasal dosing, as well as a robust cellular response, which may account for the improved two-dose survival imparted by the tetravalent vaccine, compared to a previous study that tested efficacy of TMV-DOT. Our study provides evidence that potent humoral, cellular and mucosal immunity can be achieved by optimal antigen combination, delivery, adjuvant and appropriate route of administration, to improve vaccine potency and provide protection from pathogen challenge.