Xenobiotic exposures can extensively influence the expression and alternative splicing of drug-metabolizing enzymes, including cytochromes P450 (CYPs), though their transcriptome-wide impact on splicing remains underexplored. This study used a well-characterized splicing event in the Cyp2b2 gene to validate a sandwich-cultured primary rat hepatocyte model for studying global splicing in vitro. Using endpoint PCR, RNA sequencing, and bioinformatics tools (rSeqDiff, rMATs, IGV), we analyzed differential gene expression and splicing in CYP and nuclear receptor genes, as well as the entire transcriptome, to understand how xenobiotic exposures shape alternative splicing and activate xenosensors. Primary rat hepatocytes in sandwich culture were exposed to two methylenedioxybenzene (MDB) congeners and carbamazepine, with gene expression and splicing assessed. A 3D-clustergram integrating KEGG pathway analysis with differential gene expression provided distinct splicing landscapes for each xenobiotic, showing that splicing diversity does not always align with gene expression changes. Endpoint PCR revealed a Cyp2b2v to wild-type Cyp2b2 splicing ratio near 1:1 (100

Remdesivir (GS-5734; VEKLURY) is a single diastereomer monophosphoramidate prodrug of an adenosine analog (GS-441524). Remdesivir is taken up by target cells and metabolized in multiple steps to form the active nucleoside triphosphate (GS-443902), which acts as a potent inhibitor of viral RNA-dependent RNA polymerases. Remdesivir and GS-441524 have antiviral activity against multiple RNA viruses. Here, we expand the evaluation of remdesivir’s antiviral activity to members of the families Flaviviridae , Picornaviridae , Filoviridae , Orthomyxoviridae , and Hepadnaviridae. Using cell-based assays, we show that remdesivir can inhibit infection of flaviviruses (such as dengue 1–4, West Nile, yellow fever, Zika viruses), picornaviruses (such as enterovirus and rhinovirus), and filoviruses (such as various Ebola, Marburg, and Sudan virus isolates, including novel geographic isolates), but is ineffective or is significantly less effective against orthomyxoviruses (influenza A and B viruses), or hepadnaviruses B, D, and E. In addition, remdesivir shows no antagonistic effect when combined with favipiravir, another broadly acting antiviral nucleoside analog, and has minimal interaction with a panel of concomitant medications. Our data further support remdesivir as a broad-spectrum antiviral agent that has the potential to address multiple unmet medical needs, including those related to antiviral pandemic preparedness.

The burden of atherosclerotic cardiovascular disease contributes to a large proportion of morbidity and mortality, globally. Vaccination against atherosclerosis has been proposed for over 20 years targeting different mediators of atherothrombosis; however, these have not been adequately evaluated in human clinical trials to assess safety and efficacy. Inflammation is a driver of atherosclerosis, but inflammatory mediators are essential components of the immune response. Only pathogenic forms of sTNFR2 are acted upon while preserving the membrane-bound (wild-type) TNFR2 contributions to a non-pathogenic immune response. We hypothesize that the inhibition of sTNRF2 will be more specific and offer long-term treatment options. Here we describe pre-clinical findings of an sTNFR2-targeting peptide vaccine (AtheroVax™) in a mouse model. The multiple pathways to synthesis of the soluble TNFRII receptor (sTNFRII) were identified as sTNFRII(PC), sTNFRII(Δ7), and sTNFRII(Δ7,9). The sTNFRII(Δ7) peptide, NH2-DFALPVEKPLCLQR-COOH is specific to sTNFR2 based on an mRNA splice-variant in which exon 6 is joined to exon 8. The role of sTNFRII(Δ7) as a mediator of prolonged TNFα activity by preventing degradation and clearance was investigated. Inflammation is a critical driver of onset, progression and expansion of atherosclerosis. The TNFα ligand represents a driver of inflammation that is mediated by a splice variant of TNFR2, referred to as sTNFRII(Δ7). The multiple forms of TNFRII, both membrane bound and soluble, are associated with distinctly different phenotypes. sTNFRII(PC) and sTNFRII(Δ7) are not equivalent to etanercept because they lack a clearance mechanism. The unique peptide associated with sTNFRII(Δ7) contains a linear B-cell epitope with amino acids from both exon 6 and exon 8 supporting the vaccine design. Animal studies to evaluate the vaccine are ongoing, and results will be forthcoming. We describe a peptide vaccine targeting sTNFR2 in limiting the progression of atherosclerosis. A therapeutic vaccine limiting the progression of atherosclerosis will greatly contribute to the reduction in morbidity and mortality from cardiovascular disease. It is likely the vaccine will be used in combination with the current standards of care and lifestyle modifications.

Effective therapeutics have been developed against acute Ebola virus disease (EVD) in both humans and experimentally infected nonhuman primates. However, the risk of viral persistence and associated disease recrudescence in survivors receiving these therapeutics remains unclear. In contrast to rhesus macaques that survived Ebola virus (EBOV) exposure in the absence of treatment, we discovered that EBOV, despite being cleared from all other organs, persisted in the brain ventricular system of rhesus macaque survivors that had received monoclonal antibody (mAb) treatment. In mAb-treated macaque survivors, EBOV persisted in macrophages infiltrating the brain ventricular system, including the choroid plexuses. This macrophage infiltration was accompanied by severe tissue damage, including ventriculitis, choroid plexitis, and meningoencephalitis. Specifically, choroid plexus endothelium-derived EBOV infection led to viral persistence in the macaque brain ventricular system. This resulted in apoptosis of ependymal cells, which constitute the blood–cerebrospinal fluid barrier of the choroid plexuses. Fatal brain-confined recrudescence of EBOV infection manifested as severe inflammation, local pathology, and widespread infection of the ventricular system and adjacent neuropil in some of the mAb-treated macaque survivors. This study highlights organ-specific EBOV persistence and fatal recrudescent disease in rhesus macaque survivors after therapeutic treatment and has implications for the long-term follow-up of human survivors of EVD.

Eastern equine encephalitis virus (EEEV) is mosquito-borne virus that produces fatal encephalitis in humans. We recently conducted a first of its kind study to investigate EEEV clinical disease course following aerosol challenge in a cynomolgus macaque model utilizing the state-of-the-art telemetry to measure critical physiological parameters. Here, we report the results of a comprehensive pathology study of NHP tissues collected at euthanasia to gain insights into EEEV pathogenesis. Viral RNA and proteins as well as microscopic lesions were absent in the visceral organs. In contrast, viral RNA and proteins were readily detected throughout the brain including autonomic nervous system (ANS) control centers and spinal cord. However, despite presence of viral RNA and proteins, majority of the brain and spinal cord tissues exhibited minimal or no microscopic lesions. The virus tropism was restricted primarily to neurons, and virus particles (~61-68 nm) were present within axons of neurons and throughout the extracellular spaces. However, active virus replication was absent or minimal in majority of the brain and was limited to regions proximal to the olfactory tract. These data suggest that EEEV initially replicates in/near the olfactory bulb following aerosol challenge and is rapidly transported to distal regions of the brain by exploiting the neuronal axonal transport system to facilitate neuron-to-neuron spread. Once within the brain, the virus gains access to the ANS control centers likely leading to disruption and/or dysregulation of critical physiological parameters to produce severe disease. Moreover, the absence of microscopic lesions strongly suggests that the underlying mechanism of EEEV pathogenesis is due to neuronal dysfunction rather than neuronal death. This study is the first comprehensive investigation into EEEV pathology in a NHP model and will provide significant insights into the evaluation of countermeasure.

The Joint Program Executive Office for Chemical, Biological, Radiological, and Nuclear Defense (JPEO-CBRND) began development of a broad-spectrum antiviral countermeasure against deliberate use of high-consequence viral hemorrhagic fevers (VHFs) in 2016. The effort featured comprehensive preclinical research, including laboratory testing and rapid advancement of lead molecules into nonhuman primate (NHP) models of Ebola virus disease (EVD). Remdesivir (GS-5734, Veklury, Gilead Sciences) was the first small molecule therapeutic to successfully emerge from this effort. Remdesivir is an inhibitor of RNA-dependent RNA polymerase, a viral enzyme that is essential for viral replication. Its robust potency and broad-spectrum antiviral activity against certain RNA viruses including Ebola virus and Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) led to its clinical evaluation in randomized, controlled trials (RCTs) in human patients during the 2018 EVD outbreak in the Democratic Republic of the Congo (DRC) and the ongoing Coronavirus Disease 2019 (COVID-19) pandemic today. Remdesivir was recently approved by the US Food and Drug Administration (FDA) for the treatment of COVID-19 requiring hospitalization. Substantial gaps remain in improving the outcomes of acute viral infections for patients afflicted with both EVD and COVID-19, including how to increase therapeutic breadth and strategies for the prevention and treatment of severe disease. Combination therapy that joins therapeutics with complimentary mechanisms of action appear promising, both preclinically and in RCTs. Importantly, significant programmatic challenges endure pertaining to a clear drug and biological product development pathway for therapeutics targeting biodefense and emerging pathogens when human efficacy studies are not ethical or feasible. For example, remdesivir's clinical development was facilitated by outbreaks of Ebola and SARS-CoV-2; as such, the development pathway employed for remdesivir is likely to be the exception rather than the rule. The current regulatory licensure pathway for therapeutics targeting rare, weaponizable VHF agents is likely to require use of FDA's established Animal Rule (21 CFR 314.600-650 for drugs; 21 CFR 601.90-95 for biologics). The FDA may grant marketing approval based on adequate and well-controlled animal efficacy studies when the results of those studies establish that the drug is safe and likely to produce clinical benefit in humans. In practical terms, this is anticipated to include a series of rigorous, well-documented, animal challenge studies, to include aerosol challenge, combined with human safety data. While small clinical studies against naturally occurring, high-consequence pathogens are typically performed where possible, approval for the therapeutics currently under development against biodefense pathogens will likely require the Animal Rule pathway utilizing studies in NHPs. We review the development of remdesivir as illustrative of the effort that will be needed to field future therapeutics against highly lethal, infectious agents.

Currently, the majority of treatment strategies reported for coronavirus disease (COVID-19) involve the systemic administration of drugs, in addition to other approaches including convalescent plasma.1,2 The pathogenesis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was believed to be largely localised in the lungs. Retrospective observational studies from Wuhan, China have shown subgroups of patients with symptoms affecting the cardiovascular, renal, nervous, and digestive systems.3,4 Yet the most critical cases largely encompass those suffering from acute respiratory distress syndrome (ARDS). Therefore, the authors propose a combination of local delivery of therapeutics directly to the lungs and adjunct systemic administration (i.e., intravenous infusion).

CYP3A5 is the primary CYP3A subfamily enzyme expressed in the human kidney and its aberrant expression may contribute to a broad spectrum of renal disorders. Pharmacogenetic studies have reported inconsistent linkages between CYP3A5 expression and hypertension, however, most investigators have considered CYP3A5*1 as active and CYP3A5*3 as an inactive allele. Observations of gender specific differences in CYP3A5*3/*3 protein expression suggest additional complexity in gene regulation that may underpin an environmentally responsive role for CYP3A5 in renal function. Reconciliation of the molecular mechanism driving conditional restoration of functional CYP3A5*3 expression from alternatively spliced transcripts, and validation of a morpholino-based approach for selectively suppressing renal CYP3A5 expression, is the focus of this work. Morpholinos targeting a cryptic splice acceptor created by the CYP3A5*3 mutation in intron 3 rescued functional CYP3A5 expression in vitro, and salt-sensitive cellular mechanisms regulating splicing and conditional expression of CYP3A5*3 transcripts are reported. The potential for a G-quadruplex (G4) in intron 3 to mediate restored splicing to exon 4 in CYP3A5*3 transcripts was also investigated. Finally, a proximal tubule microphysiological system (PT-MPS) was used to evaluate the safety profile of morpholinos in proximal tubule epithelial cells, highlighting their potential as a therapeutic platform for the treatment of renal disease.

Filoviruses—Ebola virus (EBOV), Marburg virus, and Sudan virus—are human pathogenic viruses, outbreaks of which have been associated with high case fatality rates. No antivirals have been approved to combat filovirus disease. Multiple experimental therapeutics have been shown to protect nonhuman primates against filovirus infection, and recent EBOV outbreaks have provided opportunities for clinical efficacy evaluations of promising investigational products. This chapter provides a comprehensive review of small molecules and other synthetic entities that have shown potential as therapeutic agents to combat filovirus disease. Summarized results are intended to convey key results from in vitro, in vivo, or clinical antiviral assessments; known mechanism(s) of action; and other relevant pharmacological characterizations of therapeutic candidates.

Efficacious therapeutics for Ebola virus disease are in great demand. Ebola virus infections mediated by mucosal exposure, and aerosolization in particular, present a novel challenge due to nontypical massive early infection of respiratory lymphoid tissues. We performed a randomized and blinded study to compare outcomes from vehicle-treated and remdesivir-treated rhesus monkeys in a lethal model of infection resulting from aerosolized Ebola virus exposure. Remdesivir treatment initiated 4 days after exposure was associated with a significant survival benefit, significant reduction in serum viral titer, and improvements in clinical pathology biomarker levels and lung histology compared to vehicle treatment. These observations indicate that remdesivir may have value in countering aerosol-induced Ebola virus disease.

More than 100 SARS-CoV-2 vaccines are in clinical and preclinical research stages,1WHOCOVID-19 vaccine tracker and landscape.https://www.who.int/publications/m/item/draft-landscape-of-covid-19-candidate-vaccinesDate: July 23, 2021Date accessed: August 14, 2021Google Scholar and some are approaching full approval by regulatory bodies. Lessons from the COVID-19 pandemic continue to extend our understanding of vaccine biology. Age-specific mortality from and immunity to SARS-CoV-2 infection have emphasised the vulnerability of older adults to COVID-19 and the higher case fatality in this population compared with younger people.2O'Driscoll M Ribeiro Dos Santos G Wang L et al.Age-specific mortality and immunity patterns of SARS-CoV-2.Nature. 2021; 590: 140-145Crossref PubMed Scopus (744) Google Scholar To achieve optimum efficacy, most of the advanced SARS-CoV-2 vaccines must be given in two doses,1WHOCOVID-19 vaccine tracker and landscape.https://www.who.int/publications/m/item/draft-landscape-of-covid-19-candidate-vaccinesDate: July 23, 2021Date accessed: August 14, 2021Google Scholar although some, such as the BNT162b2 mRNA vaccine (tozinameran; developed by Pfizer–BioNTech) and the ChAdOx1 nCoV-19 adenovirus-vector vaccine (Oxford University–AstraZeneca), have shown efficacy after the first dose.3Polack FP Thomas S Kitchin N et al.Safety and efficacy of the BNT162b2 mRNA COVID-19 vaccine.N Engl J Med. 2020; 383: 2603-2615Crossref PubMed Scopus (10080) Google Scholar, 4Voysey M Clemens SAC Madhi SA et al.Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK.Lancet. 2021; 397: 99-111Summary Full Text Full Text PDF PubMed Scopus (3420) Google Scholar These findings were obtained from studies done in younger individuals, and attempts to expand them into groups aged 80 years or older have been lacking. Increasing the interval between the first and second doses of the vaccine can help to stretch vaccine supplies; however, implementing such regimens should be based on a firm understanding of the immune responses and efficacy in the most vulnerable populations. Further exploration of human immune senescence in people aged 80 years or older should be adequately addressed to allow better monitoring of this group's immune responses to SARS-CoV-2 vaccines. In two Articles in The Lancet Healthy Longevity, Helen Parry and colleagues5Parry H Bruton R Tut G et al.Immunogenicity of single vaccination with BNT162b2 or ChAdOx1 nCoV-19 at 5–6 weeks post vaccine in participants aged 80 years or older: an exploratory analysis.Lancet Healthy Longev. 2021; (published online Aug 11.)https://doi.org/10.1016/S2666-7568(21)00169-0Summary Full Text Full Text PDF PubMed Scopus (32) Google Scholar and Gokhan Tut and colleagues,6Tut G Lancaster T Krutikov M et al.Profile of humoral and cellular immune responses to single doses of BNT162b2 or ChAdOx1 nCoV-19 vaccines in residents and staff within residential care homes (VIVALDI): an observational study.Lancet Healthy Longev. 2021; (published online Aug 19.)https://doi.org/10.1016/S2666-7568(21)00168-9Summary Full Text Full Text PDF Scopus (39) Google Scholar as part of the Paul Moss research group at the University of Birmingham, report on their investigations of the immunogenicity of a single dose of the BNT162b2 or ChAdOx1 nCoV-19 vaccines in individuals aged 80 years or older.5Parry H Bruton R Tut G et al.Immunogenicity of single vaccination with BNT162b2 or ChAdOx1 nCoV-19 at 5–6 weeks post vaccine in participants aged 80 years or older: an exploratory analysis.Lancet Healthy Longev. 2021; (published online Aug 11.)https://doi.org/10.1016/S2666-7568(21)00169-0Summary Full Text Full Text PDF PubMed Scopus (32) Google Scholar, 6Tut G Lancaster T Krutikov M et al.Profile of humoral and cellular immune responses to single doses of BNT162b2 or ChAdOx1 nCoV-19 vaccines in residents and staff within residential care homes (VIVALDI): an observational study.Lancet Healthy Longev. 2021; (published online Aug 19.)https://doi.org/10.1016/S2666-7568(21)00168-9Summary Full Text Full Text PDF Scopus (39) Google Scholar In the complementary Articles, immune responses were explored in people aged 80 years or older living independently (n=165), and in residents (n=35; median age 87 years [IQR 77–90]) and staff (n=89; 48 years [35·5–56]) of long-term care facilities (LTCFs). Encouragingly, single doses of either the BNT162b2 or ChAdOx1 nCoV-19 vaccine reliably elicited humoral immunity in older people in both studies. In Tut and colleagues' study,6Tut G Lancaster T Krutikov M et al.Profile of humoral and cellular immune responses to single doses of BNT162b2 or ChAdOx1 nCoV-19 vaccines in residents and staff within residential care homes (VIVALDI): an observational study.Lancet Healthy Longev. 2021; (published online Aug 19.)https://doi.org/10.1016/S2666-7568(21)00168-9Summary Full Text Full Text PDF Scopus (39) Google Scholar humoral immune responses to the vaccines in participants without serological evidence of previous SARS-CoV-2 infection were slower to peak in LTCF residents than in LTCF staff, with the apparent correlation between age and spike-specific IgG antibody titre disappearing only in the subset of samples taken more than 42 days since vaccination. The effect of the slow increase in spike-specific antibodies in this population should be further investigated. Additionally, Tut and colleagues' study provided a preliminary indication of the diminished responses of older people to some of the circulating SARS-CoV-2 variants, and should alert us to the possibility that the slow kinetics of responses to vaccines in this population might hinder the protection of such individuals against future variants of SARS-CoV-2. The use of adjuvants to more rapidly and fully stimulate humoral immune responses in older people might help efforts to protect this population. The two studies also examined cellular immune responses to the vaccines. Cellular immune responses were weaker and slower to develop than humoral immunity and positive spike-specific T-cell responses were found only in a small subset of vaccinated individuals in both studies, although those with evidence of previous SARS-CoV-2 infection in Tut and colleagues' study all showed positive T-cell responses. At 5–6 weeks post vaccination, the ChAdOx1 nCoV-19 vaccine induced a higher level of cellular responses than did the BNT162b2 vaccine.5Parry H Bruton R Tut G et al.Immunogenicity of single vaccination with BNT162b2 or ChAdOx1 nCoV-19 at 5–6 weeks post vaccine in participants aged 80 years or older: an exploratory analysis.Lancet Healthy Longev. 2021; (published online Aug 11.)https://doi.org/10.1016/S2666-7568(21)00169-0Summary Full Text Full Text PDF PubMed Scopus (32) Google Scholar These Articles address a crucial concern regarding the interval between the first and second doses of vaccine in older people. Extending the vaccine interval permits the acceleration of vaccine population coverage during the pandemic. The findings might support extending the interval to up to 7 weeks in individuals aged 80 years and older. Evidence of previous natural infection with SARS-CoV-2 was found in 12 (34%) of 35 residents of LTCFs,6Tut G Lancaster T Krutikov M et al.Profile of humoral and cellular immune responses to single doses of BNT162b2 or ChAdOx1 nCoV-19 vaccines in residents and staff within residential care homes (VIVALDI): an observational study.Lancet Healthy Longev. 2021; (published online Aug 19.)https://doi.org/10.1016/S2666-7568(21)00168-9Summary Full Text Full Text PDF Scopus (39) Google Scholar suggesting the possibility of bias in this population and limiting the generalisability of the results to people living independently, in whom rates of previous infection differ. A single dose of vaccine is effectively a booster in people who have previously been infected, and both antibody titres and cellular immunity were significantly higher in such individuals. Additionally, randomisation and group sizes represent a significant challenge in conducting studies in individuals aged 80 years and older, which limits the significance of study conclusions. Another limitation of the study is the measure of functional immune responses to vaccination; functional humoral responses and correlates of immune protection are not fully understood for vaccination in all age groups. However, given the greater fatality rate of SARS-CoV-2 infection in people aged 80 years and older, and the proximity of this age to average life expectancy, a simple follow-up measure of greater duration of survival might provide insight into a functional immune response in vaccinated individuals. Perhaps the most surprising finding in Tut and colleague's study was the levelling effect of previous infection on the overall immune responses of older versus younger participants. Older participants with serological evidence of previous SARS-CoV-2 infection had robust immune responses to the vaccine and their antibodies were of higher concentration and perhaps greater functionality for neutralising the virus compared with older people who had not previously been infected. These data further support the importance of vaccination in people with previous exposure to SARS-CoV-2 and suggest further expansion of the immune response can occur in older adults who were previously infected. Further studies should aim to enhance our understanding of how the timing of vaccination post infection could benefit older adults. The influence of SARS CoV-2 variants of concern on vaccine protection has been actively evaluated in younger populations. The observation that antibody inhibition of spike–ACE2 binding by the B.1.351 (beta) and P.1 (gamma) variants of concern were low in samples from older adults without evidence of previous infection in Tut and colleagues' study is of keen interest,6Tut G Lancaster T Krutikov M et al.Profile of humoral and cellular immune responses to single doses of BNT162b2 or ChAdOx1 nCoV-19 vaccines in residents and staff within residential care homes (VIVALDI): an observational study.Lancet Healthy Longev. 2021; (published online Aug 19.)https://doi.org/10.1016/S2666-7568(21)00168-9Summary Full Text Full Text PDF Scopus (39) Google Scholar and suggests that the limitations of vaccine protection against variants of concern might be substantial in this population, especially considering the modest cellular immune response elicited by a single dose of vaccine in this group. Exactly how extended-interval dosing might protect against future variants of concern is an important consideration and additional studies could help to better define dose regimens in people aged 80 years and older. Collectively, these observations highlight the potential greater vulnerability of vaccinated older adults to infection by variants of concern compared with younger people. We declare no competing interests. Profile of humoral and cellular immune responses to single doses of BNT162b2 or ChAdOx1 nCoV-19 vaccines in residents and staff within residential care homes (VIVALDI): an observational studyImmunogenicity of single vaccination with BNT162b2 or ChAdOx1 nCoV-19 at 5–6 weeks post vaccine in participants aged 80 years or older: an exploratory analysis

The ongoing responses to the COVID-19 pandemic have resulted in diverse vaccine-based solutions that are advancing our understanding of medical science.1 Randomised, placebo-controlled clinical trials are providing a unique opportunity to compare the safety and immunogenicity of several different vaccine platforms, including vectored, DNA, inactivated virus, mRNA, and protein subunit vaccines. Strategic differences within each vaccine platform, such as dimer versus trimer protein subunits or modifications in protein design based on dynamic structural modelling, are providing deeper insights into the optimal vaccines of the future—a silver lining to the dark cloud of the COVID-19 pandemic.

The PALM trial in the Democratic Republic of the Congo identified a statistically significant survival benefit for two monoclonal antibody-based therapeutics in the treatment of acute Ebola virus disease; however, substantial gaps remain in improving the outcomes of acute Ebola virus disease and for the survivors. Ongoing efforts are needed to develop more effective strategies, particularly for individuals with severe disease, for prevention and treatment of viral persistence in immune-privileged sites, for optimisation of post-exposure prophylaxis, and to increase therapeutic breadth. As antibody-based approaches are identified and advanced, promising small-molecule antivirals currently in clinical stage development should continue to be evaluated for filovirus diseases, with consideration of their added value in combination approaches with bundled supportive care, their penetration in tissues of interest, the absence of interaction with glycoprotein-based vaccines, and filoviral breadth.

Definitive pharmacological therapies for COVID-19 have yet to be identified. Several hundred trials are ongoing globally in the hope of a solution. However, nearly all treatments rely on systemic delivery but COVID-19 damages the lungs preferentially. The use of a targeted delivery approach is reviewed where engineered products are able to reach damaged lung tissue directly, which includes catheter-based and aerosol-based approaches. In this review we have outlined various target directed approaches which include microbubbles, extracellular vesicles including exosomes, adenosine nanoparticles, novel bio-objects, direct aerosol targeted pulmonary delivery and catheter-based drug delivery with reference to their relative effectiveness for the specific lesions. Currently several trials are ongoing to determine the effectiveness of such delivery systems alone and in conjunction with systemic therapies. Such approaches may prove to be very effective in the controlled and localized COVID-19 viral lesions in the lungs and potential sites. Moreover, localized delivery offered a safer delivery mode for such drugs which may have systemic adverse effects.

Many inactivated vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are being tested at various clinical stages. Most of these vaccines are formulated with aluminium hydroxide, and one, VLA-2001, has two adjuvants, CpG oligodeoxynucleotides and aluminium hydroxide.1Flanagan KL Best E Crawford NW et al.Progress and pitfalls in the quest for effective SARS-CoV-2 (COVID-19) vaccines.Front Immunol. 2020; 11579250Crossref Scopus (74) Google Scholar, 2WHODraft landscape of COVID-19 candidate vaccines.https://www.who.int/publications/m/item/draft-landscape-of-covid-19-candidate-vaccinesDate: Jan 15, 2021Date accessed: January 15, 2021Google Scholar Because of the ease of production and scale-up and relatively low cost, inactivated vaccines can capture a sizeable portion of the SARS-CoV-2 vaccine landscape. Inactivated vaccines are well established and can provide advantages in a variety of distinct populations, including those with degrees of immune senescence. Given that the risk of more severe COVID-19 increases with age, the clinical evaluation of the responses of older adults to vaccines is essential.3US Centers for Disease Control and PreventionCOVID-19—older adults.http://cdc.gov/coronavirus/2019-ncov/need-extra-precautions/older-adults.htmlDate: Dec 13, 2020Date accessed: January 4, 2021Google Scholar In The Lancet Infectious Diseases, Zhiwei Wu and colleagues4Wu Z Hu Y Xu M et al.Safety, tolerability, and immunogenicity of an inactivated SARS-CoV-2 vaccine (CoronaVac) in healthy adults aged 60 years and older: a randomised, double-blind, placebo-controlled, phase 1/2 clinical trial.Lancet Infect Dis. 2021; (published online Feb 3.)https://doi.org/10.1016/S1473-3099(20)30987-7Summary Full Text Full Text PDF Scopus (378) Google Scholar report the results of a randomised, double-blind, placebo-controlled phase 1/2 clinical trial evaluating an inactivated COVID-19 vaccine, CoronaVac, in healthy adults aged 60 years and older (72 in phase 1 and 350 in phase 2). The aluminium hydroxide-adjuvanted vaccine was given as two injections (days 0 and 28), and three different doses were tested (1·5 μg, 3 μg, and 6 μg per injection). The vaccine showed good safety and tolerability; adverse reactions, the most frequent being injection site pain (39 [9%] of 421 participants), were all mild or moderate in severity and no serious adverse events related to vaccination were recorded. Neutralising antibody titres were measured for all doses 28 days after the second injection. Because similar responses were seen with doses of 3 μg (seroconversion rate 98·0% [95% CI 92·8–99·8]) and 6 μg (99·0% [94·5–100·0]) in phase 2, and these doses elicited better responses than did the 1·5 μg dose, the authors proposed the use of a 3 μg dose in the phase 3 trial. This report is a companion to an earlier report of the safety and immunogenicity of CoronaVac in adults aged 18–59 years.5Zhang Y Zeng G Pan H et al.Safety, tolerability, and immunogenicity of an inactivated SARS-CoV-2 vaccine in healthy adults aged 18–59 years: a randomised, double-blind, placebo-controlled, phase 1/2 clinical trial.Lancet Infect Dis. 2020; (published online Nov 17.)https://doi.org/10.1016/S1473-3099(20)30843-4Summary Full Text Full Text PDF Scopus (973) Google Scholar Several limitations were acknowledged in this report, which are consistent with rapid-fire trials executed during the pandemic. The durability of immune response and latent adverse effects were not evaluated during the 2 month period. All participants were of Han Chinese ethnicity, and greater ethnic diversity in populations will be examined in the phase 3 trials. The 4 week interval from prime to boost might not be optimal, and no measures of T-cell or cytokine responses were included. However, these reported limitations represent a veneer of deeper issues capable of shaking confidence in vaccine utility in an ageing population. Correlates of immune protection have not been established for SARS-CoV-2 vaccines to date, posing a foundational constraint to any vaccine development, although many vaccines have been granted emergency use approvals around the globe. Comparisons of various vaccine platforms have been hampered because, until recently, there were no standard pooled convalescent sera from infected individuals to use as a reference standard.6NIBSCCoronavirus (COVID-19)-related research reagents available from the NIBSC.https://www.nibsc.org/science_and_research/idd/cfar/covid-19_reagents.aspxDate accessed: January 4, 2021Google Scholar Interpretation of immune responses is limited in that no consensus standard methods for measuring neutralising antibody titres are in place, thereby confounding comparisons between age groups and comparisons with different vaccine strategies. Immune senescence is complex and there are no validated methods to identify early stages or measures of severity.7Cunha LL Perazzio SF Azzi J Cravedi P Riella LV Remodeling of the immune response with aging: immunosenescence and its potential impact on COVID-19 immune response.Front Immunol. 2020; 111748Crossref Scopus (156) Google Scholar A correlation between anti-receptor-binding domain IgG and neutralising antibodies has been reported for adults aged 18–59 years,5Zhang Y Zeng G Pan H et al.Safety, tolerability, and immunogenicity of an inactivated SARS-CoV-2 vaccine in healthy adults aged 18–59 years: a randomised, double-blind, placebo-controlled, phase 1/2 clinical trial.Lancet Infect Dis. 2020; (published online Nov 17.)https://doi.org/10.1016/S1473-3099(20)30843-4Summary Full Text Full Text PDF Scopus (973) Google Scholar but this relationship might not hold true for older individuals with various stages of immune senescence. A similar relationship between T-cell responses and IFN-γ observed in adults might not exist in immune-senescent individuals. We encourage measurement of comparable immune features in future studies of individuals aged 18–59 years or 60 years and older. A diminished T-cell response in an older population is anticipated, but a possible reduction in neutralising antibody titre in people older than 70 years has not been fully studied. We encourage a granular evaluation of age groups to permit identification of age-related limitations in vaccine utility. IgM or the transition to IgG were not reported in Wu and colleagues' study,4Wu Z Hu Y Xu M et al.Safety, tolerability, and immunogenicity of an inactivated SARS-CoV-2 vaccine (CoronaVac) in healthy adults aged 60 years and older: a randomised, double-blind, placebo-controlled, phase 1/2 clinical trial.Lancet Infect Dis. 2021; (published online Feb 3.)https://doi.org/10.1016/S1473-3099(20)30987-7Summary Full Text Full Text PDF Scopus (378) Google Scholar so the integrity of B-cell function is not known. In general, it might be safe to proceed, but adjustments in dose and the interval between prime and boost in the population aged 60 years and older might be necessary, based on the measures from this study. 100 million people will soon have recovered from SARS-CoV-2 infection. Most recovered individuals have had antibody and T-cell responses against multiple SARS-CoV-2 proteins, but vaccination of these individuals might be necessary to prevent reinfection. Compared with other vaccines targeting only the spike protein, inactivated vaccines could provide an added benefit to these individuals by boosting their T-cell responses against many of the SARS-CoV-2 proteins. Advancements in the development of an inactivated vaccine provide additional opportunities, but the pace of development must be balanced with quantitative measures of safety and efficacy. Inclusion of additional viral antigens in the inactivated vaccine could provide efficacy over time and as variants emerge. However, shifting viral antigens could also predispose an inactivated vaccine to causing antibody-dependent enhancement of disease.8Jeyanathan M Afkhami S Smaill F Miller MS Lichty BD Xing Z Immunological considerations for COVID-19 vaccine strategies.Nat Rev Immunol. 2020; 20: 615-632Crossref PubMed Scopus (696) Google Scholar It is important to create a vaccine portfolio composed of different strategies for a more robust defence against the SARS-CoV-2 pandemic. We declare no competing interests. Safety, tolerability, and immunogenicity of an inactivated SARS-CoV-2 vaccine (CoronaVac) in healthy adults aged 60 years and older: a randomised, double-blind, placebo-controlled, phase 1/2 clinical trialCoronaVac is safe and well tolerated in older adults. Neutralising antibody titres induced by the 3 μg dose were similar to those of the 6 μg dose, and higher than those of the 1·5 μg dose, supporting the use of the 3 μg dose CoronaVac in phase 3 trials to assess protection against COVID-19. Full-Text PDF

The human genome encodes 48 nuclear receptor (NR) genes, whose translated products transform chemical signals from endo-xenobiotics into pleotropic RNA transcriptional profiles that refine drug metabolism. This review describes the remarkable diversification of the 48 human NR genes, which are potentially processed into over 1000 distinct mRNA transcripts by alternative splicing (AS). The average human NR expresses ∼21 transcripts per gene and is associated with ∼7000 single nucleotide polymorphisms (SNPs). However, the rate of SNP accumulation does not appear to drive the AS process, highlighting the resilience of NR genes to mutation. Here we summarize the altered tissue distribution/function of well characterized NR splice variants associated with human disease. We also describe a cassette exon visualization pictograph methodology for illustrating the location of modular, cassette exons in genes, which can be skipped in-frame, to facilitate the study of their functional relevance to both drug metabolism and NR evolution. We find cassette exons associated with all of the functional domains of NR genes including the DNA and ligand binding domains. The matrix of inclusion or exclusion for functional domain-encoding cassette exons is extensive and capable of significant alterations in cellular phenotypes that modulate endo-xenobiotic metabolism. Exon inclusion options are differentially distributed across NR subfamilies, suggesting group-specific conservation of resilient functionalities. A deeper understanding of this transcriptional plasticity expands our understanding of how chemical signals are refined and mediated by NR genes. This expanded view of the NR transcriptome informs new models of chemical toxicity, disease diagnostics, and precision-based approaches to personalized medicine. SIGNIFICANCE STATEMENT This review explores the impact of alternative splicing (AS) on the human nuclear receptor (NR) superfamily and highlights the dramatic expansion of more than 1000 potential transcript variants from 48 individual genes. Xenobiotics are increasingly recognized for their ability to perturb gene splicing events, and here we explore the differential sensitivity of NR genes to AS and chemical exposure. Using the cassette exon visualization pictograph methodology, we have documented the conservation of splice-sensitive, modular, cassette exon domains among the 48 human NR genes, and we discuss how their differential expression profiles may augment cellular resilience to oxidative stress and fine-tune adaptive, metabolic responses to endo-xenobiotic exposure.

No definitive therapies for COVID-19 have yet to be identified. The several hundred planned or ongoing clinical trials globally will provide some insights into therapies that may or may not work. The overwhelming majority of therapeutics relies on the systemic delivery of drugs; however, COVID-19 is largely localized to the lungs with some subgroups afflicted in other organ systems. We propose the use of a targeted drug delivery approach in which therapeutics can be delivered using engineered delivery vehicles to reach damaged lung tissue directly.