Andrographolide inhibits chikungunya virus infection by up-regulating host innate immune pathways

Objective: To investigate the therapeutic efficacy of andrographolide, a plant derived compound, against chikungunya virus(CHIKV) infection. Methods: Using flow cytometry and immunoblotting assay, in vitro viral protein expression was studied in THP-1 cells line. In Balb/c mouse neonates, viral RNA copy number was determined by real time PCR. Results:The results showed reduced CHIKV protein expression on andrographolide treatment in CHIKV-infected human peripheral blood mononuclear cells, Vero cells and THP-I cell line.In vivo, andrographolide treatment to CHIKV-infected neonates reduced viral RNA copy number. Further. andrographolide also increased cytotoxic T lymphocytes both in vitro and in vivo. Andrographolide also activated host innate immune pathways, viz., protein kinase R.phosphorylated eukaryotic initiation factor 2 α, retinoic acid inducible gene-Ⅰ and interferon regulatory factor 3/7, thereby increasing IFN-a secretion. CHIKV-induced nuclear factor κlight chain enhancer of activated B cells and tumor necrosis factor-a was also reduced on andrographolide treatment. Conclusion: Andrographolide inhibits CHIKV by suppressing viral protein expression and up-regulating host innate immunity and hence could be an effective therapeutic agent against CHIKV infection.

Parsonage-Turner syndrome following chikungunya virus infection:A case report

Rationale: Parsonage-Turner syndrome is a rare syndrome of unknown etiology, affecting mainly the lower motor neurons of the brachial plexus.Chikungunya fever is a mosquito-borne viral disease characterized by acute fever and polyarthritis/polyarthralgia.Patient concerns: A 54-year-old Brazilian male patient who presented with a 2-day history of fever(temperature 38.8 ℃), arthralgia, erythematous rash, diffuse osteomuscular pain and headache, which evolved into left shoulder pain associated with morning stiffness.Diagnosis: Parsonage-Turner syndrome and chikungunya fever.Interventions: Symptomatic treatment(a combination of short-acting dypirone(500 mg every 6 h) and slow-release opioids(tramadol 100 mg every 4 h) and physiotherapy/rehabilitation with improvement.Outcomes: The patient was improved and discharged, remaining with symptomatic treatment and physiotherapy/rehabilitation.Lessons: To the best of our knowledge, there were no reports of Parsonage-Turner syndrome following chikungunya virus infection.Awareness of the possibility of this rare association is important.The present case report highlights the importance of awareness of this association as a new cause of morbidity in patients with chikungunya virus infection.

Prediction of promiscuous T cell epitopes in RNA dependent RNA polymerase of Chikungunya virus

Objective: To explore RNA dependent RNA polymerase of Chikungunya virus(CHIKV) and develop T cell based epitopes with high antigenicity and good binding affinity for the human leukocyte antigen(HLA) classes as targets for epitopes based CHIKV vaccine. Methods: In this study we downloaded 371 non-structural protein 4 protein sequences of CHIKV belonging to different regions of the world from the US National Institute of Allergy and Infectious Diseases(NIAID) virus pathogen resource database. All the sequences were aligned by using CLUSTALW software and a consensus sequence was developed by using Uni Pro U Gene Software version 1.2.1. PropredⅠand Propred software were used to predict HLAⅠ and HLAⅡ binding promiscuous epitopes from the consensus sequence of non-structural protein 4 protein. The predicted epitopes were analyzed to determine their antigenicity through Vaxijen server version 2.0. All the HLAⅠ binding epitopes were scanned to determine their immunogenic potential through the Immune Epitope Database(IEDB). All the predicted epitopes of our study were fed to IEDB database to determine whether they had been tested earlier. Results: Twenty two HLA class Ⅱ epitopes and eight HLA classⅠepitopes were predicted. The promiscuous epitopes WMNMEVKII at position 486–494 and VRRLNAVLL at 331–339 were found to bind with 37 and 36 of the 51 HLA class Ⅱ alleles respectively. Epitope MANRSRYQS at position 58–66 and epitopes YQSRKVENM at positions 64–72 were predicted to bind with 12 and 9 HLAⅠI alleles with antigenicity scores of 0.754 9 and 1.013 0 respectively. Epitope YSPPINVRL was predicted to bind 18 HLAⅠ alleles and its antigenicity score was 1.425 9 and immunogenicity score was 0.173 83. This epitope is very useful in the preparation of a universal vaccine against CHIKV infection. Conclusions: Epitopes reported in this study showed promiscuity, antigenicity as well as good binding affinity for the HLA classes. These epitopes will provide the baseline for development of efficacious vaccine for CHIKV.

The Chikungunya virus: An emerging US pathogen

BACKGROUND:The Chikungunya(CHIK)virus was recently reported by the CDC to have spread to the United States.We report an early documented case of CHIK from the state of Pennsylvania after a patient recently returned from Haiti in June of 2014.METHODS:A 39-year-old man presented to the emergency department complaining of fever,fatigue,polyarthralgias and a diffuse rash for two days.Four days before,he returned from a mission trip to Haiti and reported that four of his accompanying friends had also become ill.A CHIK antibody titer was obtained and it was found to be positive.During his hospital stay,he responded well to supportive care,including anti-inflammatories,intravenous hydration and anti-emetics.RESULTS:His condition improved within two days and he was ultimately discharged home.CONCLUSIONS:Manifestations of CHIK can be similar to Dengue fever,which is transmitted by the same species of mosquito,and occasionally as a co-infection.Clinicians should include Chikungunya virus in their differential diagnosis of patients who present with fever,polyarthralgia and rash with a recent history of travel to endemic areas,including those within the United States.

Pathogenesis of the Chikungunya virus and the host immunity response

Along with the running COVID-19 pandemic by the severe acute respiratory syndrome coronavirus 2,the Chikungunya virus is already known as the causative agent of re-emerging Chikungunya fever in many countries after several years of latency;and it’s certainly one of the most important clinical issues possibly due to the lack of appropriate vaccination.Therefore,continuous study and monitoring of this disease outbreak demand attention by the relevant health professionals.Present review has been written in the light of the recently available reports on the Chikungunya virus infection.The genomic structure and its impact on the viral epidemiology,the possible protective immunity,and the infection mitigation strategies have been discussed.It’s already well known that the Chikungunya virus can start infection after getting entrance into the blood circulation through the mosquito bites followed by the dissemination into the major organs like liver,brain,eye,joints and lymph nodes in order to inaugurate the infectivity.Apparently,the occurrence of death is very rare but the extreme fatality and morbidity may occur if the patient has other underlying disease conditions.The molecular aspects of the virus,the site-specific damages caused by the viral infection,and finally,the public awareness of such viral infection as discussed in the current review would help to maintain the public health sustainability especially in the developing countries whereby the knowledge on the required hygiene is poor.

In silico identification of antiviral compounds for the treatment of chikungunya virus infection:qsar modelling and md simulation analysis

Chikungunya virus(CHIKV),transmitted by arthropods,has gained global recognition for its impact on public health.It has expanded globally,including Africa,Asia,and the Indian subcontinent,and has a helicase protein in its genome that is crucial for its replication.Thus,the study targeted the helicase protein of CHIKV with 745 antiviral compounds using an ML-based QSAR model and molecular docking.Top binders(5279172,78161839,6474310,and 5330286)were selected for MD simulation based on the control(Silvestrol).All compounds had the highest binding scores,with 78161839 showing the most consistent RMSD and the least conformational variation,indicating high stability.It also showed the lowest binding free energy(ΔG¼31.31 kcal/mol),indicating energetically favourable binding.PCA and FEL also depicted the stable complex confirmation of the protein and 78161839 complex during the 100 ns simulation.Overall,this study aimed to identify helicase function antiviral binders that could be experimentally tested for treating CHIKV.

Elucidating cellular interactome of chikungunya virus identifies host dependency factors

Chikungunya virus(CHIKV)is a re-emerging mosquito-transmitted RNA virus causing joint and muscle pain.To better understand how CHIKV rewires the host cell and usurps host cell functions,we generated a systematic CHIKV-human protein-protein interaction map and revealed several novel connections that will inform further mechanistic studies.One of these novel interactions,between the viral protein E1 and STIP1 homology and U-box containing protein 1(STUB1),was found to mediate ubiquitination of E1 and degrade E1 through the proteasome.Capsid associated with G3BP1,G3BP2 and AAAþATPase valosin-containing protein(VCP).Furthermore,VCP inhibitors blocked CHIKV infection,suggesting VCP could serve as a therapeutic target.Further work is required to fully understand the functional consequences of these interactions.Given that CHIKV proteins are conserved across alphaviruses,many virus-host protein-protein interactions identified in this study might also exist in other alphaviruses.Construction of interactome of CHIKV provides the basis for further studying the function of alphavirus biology.

Recent progress on chikungunya virus research

Chikungunya virus(CHIKV) is an arbovirus transmitted by Aedes mosquitos in tropical and subtropical regions across the world. After decades of sporadic outbreaks, it re-emerged in Africa,Asia, India Ocean and America suddenly, causing major regional epidemics recently and becoming a notable global health problem. Infection by CHIKV results in a spectrum of clinical diseases including an acute self-limiting febrile illness in most individuals, a chronic phase of recurrent join pain in a proportion of patients, and long-term arthralgia for months to years for the unfortunate few. No specific anti-viral drugs or licensed vaccines for CHIKV are available so far. A better understanding of virus-host interactions is essential for the development of therapeutics and vaccines. To this end, we reviewed the existing knowledge on CHIKV's epidemiology, clinical presentation, molecular virology, diagnostic approaches, host immune response, vaccine development, and available animal models. Such a comprehensive overview, we believe, will shed lights on the promises and challenges in CHIKV vaccine development.

Extensive evolution analysis of the global chikungunya virus strains revealed the origination of CHIKV epidemics in Pakistan in 2016

Chikungunya virus(CHIKV) is a mosquito-borne virus that causes epidemics widely in the world especially in the tropical and subtropical regions. Phylogenetic analysis has found that the CHIKV lineages were associated with the spatial and temporal distributions, which were related to the virus adaption to the major mosquito species and their distributions. In this study, we reported the complete genome sequences of eight CHIKV isolates from the outbreak in Pakistan last year. Then we reviewed the evolutionary history using extensive phylogenetic analysis, analyzed lineagespecific substitutions in viral proteins, and characterized the spreading pathway of CHIKV strains including the Pakistani strains. The results showed that the Pakistani stains belonged to the ECSA.IOL sub-lineage and derived from India. The genetic properties of the Pakistani strains including the adaptive substitution to vectors were further characterized, and the potential risks from the occurrence of CHIKV infection in Pakistan were discussed. These results provided better understanding of CHIKV evolution and transmission in the world and revealed the possible origination of the CHIKV outbreak and epidemic in Pakistan, which would promote the disease prevention and control in the identified countries and territories with the history of CHIKV infections as well as new regions with potential risk of CHIKV outbreaks.

An mRNA vaccine encoding Chikungunya virus E2-E1 protein elicits robust neutralizing antibody responses and CTL immune responses

Arthropod-borne chikungunya virus(CHIKV)infection can cause a debilitating arthritic disease in human.However,there are no specific antiviral drugs and effective licensed vaccines against CHIKV available for clinical use.Here,we developed an m RNA-lipid nanoparticle(m RNA-LNP)vaccine expressing CHIKV E2-E1 antigen,and compared its immunogenicity with soluble recombinant protein s E2-E1 antigen expressed in S2 cells.For comparison,we first showed that recombinant protein antigens mixed with aluminum adjuvant elicit strong antigenspecific humoral immune response and a moderate cellular immune response in C57BL/6 mice.Moreover,s E2-E1vaccine stimulated 12-23 folds more neutralizing antibodies than s E1 vaccine and s E2 vaccine.Significantly,when E2-E1 gene was delivered by an m RNA-LNP vaccine,not only the better magnitude of neutralizing antibody responses was induced,but also greater cellular immune responses were generated,especially for CD8+T cell responses.Moreover,E2-E1-LNP induced CD8~+T cells can perform cytotoxic effect in vivo.Considering its better immunogenicity and convenience of preparation,we suggest that more attention should be placed to develop CHIKV E2-E1-LNP m RNA vaccine.

Detection, isolation, and characterization of chikungunya viruses associated with the Pakistan outbreak of 2016–2017

The chikungunya virus(CHIKV) is a mosquito-transmitted alphavirus, which has infected millions of people in Africa, Asia, Americas, and Europe since it reemerged in India and Indian Ocean regions in 2005–2006. Starting in the middle of November 2016, CHIKV has been widely spread, and more than 4,000 cases of infections in humans were confirmed in Pakistan. Here, we report the first isolation and characterization of CHIKV from the Pakistan outbreak. Eight CHIKV strains were newly isolated from human serum samples using a cell culture procedure. A full-length genome sequence and eight complete envelope(E1) sequences of CHIKV from Pakistan were obtained in this study. Alignment of the CHIKV E1 sequences revealed that the eight new CHIKV isolates were highly homogeneous, with only two nonsynonymous substitutions found at generally conserved sites(E99 and Q235). Based on the comparison of 342 E1 sequences, the two nonsynonymous mutations were located in well-recognized domains associated with viral functions such as the cell fusion and vector specificity, suggesting their potential functional importance. Phylogenetic analysis indicated that the CHIKV strains from Pakistan originated from CHIKV circulating in the Indian region. This study helps elucidate the epidemics of CHIKV in Pakistan and also provides a foundation for studies of evolution and expansion of CHIKV in South Asia.

Countries at risk of importation of chikungunya virus cases from Southern Thailand: A modeling study

Southern Thailand has been experiencing a large chikungunya virus(CHIKV)outbreak since October 2018.Given the magnitude and duration of the outbreak and its location in a popular tourist destination,we sought to determine international case exportation risk and identify countries at greatest risk of receiving travel-associated imported CHIKV cases.We used a probabilistic model to estimate the expected number of exported cases from Southern Thailand between October 2018 and April 2019.The model incorporated data on CHIKV natural history,infection rates in Southern Thailand,average length of stay for tourists,and international outbound air passenger numbers from the outbreak area.For countries highly connected to Southern Thailand by air travel,we ran 1000 simulations to estimate the expected number of imported cases.We also identified destination countries with conditions suitable for autochthonous CHIKV transmission.Over the outbreak period,we estimated that an average of 125(95%credible interval(CrI):102e149)cases would be exported from Southern Thailand to international destinations via air travel.China was projected to receive the most cases(43,95%CrI:30e56),followed by Singapore(7,95%CrI:2e12)and Malaysia(5,95%CrI:1e10).Twenty-three countries were projected to receive at least one imported case,and 64%of these countries had one or more regions that could potentially support autochthonous CHIKV transmission.The overall risk of international exportation of CHIKV cases associated with the outbreak is Southern Thailand is high.Our model projections are consistent with recent reports of CHIKV in travelers returning from the region.Countries should be alert to the possibility of CHIKV infection in returning travelers,particularly in regions where autochthonous transmission is possible.

Development of a Specific CHIKV-E2 Monoclonal Antibody for Chikungunya Diagnosis

Chikungunya fever is a vector-borne viral disease transmitted to humans by chikungunya virus(CHIKV)-infected mosquitoes.There have been many outbreaks of CHIKV infection worldwide,and the virus poses ongoing risks to global health.To prevent and control CHIKV infection,it is important to improve the current CHIKV diagnostic approaches to allow for the detection of low CHIKV concentrations and to correctly distinguish CHIKV infections from those due to other mosquito-transmitted viruses,including dengue virus(DENV),Japanese encephalitis virus(JEV),and Zika virus(ZIKV).Here,we produced monoclonal antibodies(mAbs)against the CHIKV envelope 2 protein(CHIKV-E2)and compared their sensitivity and specificity with commercially available mAbs using enzyme-linked immunosorbent assays(ELISA).Two anti-CHIKV-E2 mAbs,19-1 and 21-1,showed higher binding affinities to CHIKV-E2 protein than the commercial mAbs did.In particular,the 19-1 mAb had the strongest binding affinity to inactivated CHIKV.Moreover,the 19-1 mAb had very little cross-reactivity with other mosquito-borne viruses,such as ZIKV,JEV,and DENV.These results suggest that the newly produced anti-CHIKV-E2 mAb,19-1,could he used for CHIKV diagnostic approaches.

Threats of Zika virus transmission for Asia and its Hindu-Kush Himalayan region

Asia and its Hindu Kush Himalayan(HKH)region is particularly vulnerable to environmental change,especially climate and land use changes further influenced by rapid population growth,high level of poverty and unsustainable development.Asia has been a hotspot of dengue fever and chikungunya mainly due to its dense human population,unplanned urbanization and poverty.In an urban cycle,dengue virus(DENV)and chikungunya virus(CHIKV)are transmitted by Aedes aegypti and Ae.albopictus mosquitoes which are also competent vectors of Zika virus(ZIKV).Over the last decade,DENV and CHIKV transmissions by Ae.aegypti have extended to the Himalayan countries of Bhutan and Nepal and ZIKV could follow in the footsteps of these viruses in the HKH region.The already established distribution of human-biting Aedes mosquito vectors and a naïve population with lack of immunity against ZIKV places the HKH region at a higher risk of ZIKV.Some of the countries in the HKH region have already reported ZIKV cases.We have documented an increasing threat of ZIKV in Asia and its HKH region because of the high abundance and wide distribution of human-biting mosquito vectors,climate change,poverty,report of indigenous cases in the region,increasing numbers of imported cases and a naïve population with lack of immunity against ZIKV.An outbreak anywhere is potentially a threat everywhere.Therefore,in order to ensure international health security,all efforts to prevent,detect,and respond to ZIKV ought to be intensified now in Asia and its HKH region.To prepare for possible ZIKV outbreaks,Asia and the HKH region can also learn from the success stories and strategies adopted by other regions and countries in preventing ZIKV and associated complications.The future control strategies for DENV,CHIKV and ZIKV should be considered in tandem with the threat to human well-being that is posed by other emerging and re-emerging vector-borne and zoonotic diseases,and by the continuing urgent need to strengthen public primary healthcare systems in the region.

In Vitro Inhibition of Alphaviruses by Lycorine

Chikungunya virus(CHIKV) is a mosquito-borne alphavirus. As an emerging virus, CHIKV imposes a threat to public health. Currently, there are no vaccines or antivirals available for the prevention of CHIKV infection. Lycorine, an alkaloid from Amaryllidaceae plants, has antiviral activity against a number of viruses such as coronavirus, flavivirus and enterovirus. In this study, we found that lycorine could inhibit CHIKV in cell culture at a concentration of 10 lmol/L without apparent cytotoxicity. In addition, it exhibited broad-spectrum anti-alphavirus activity, including Sindbis virus(SINV),Semliki Forest virus(SFV), and Venezuelan equine encephalomyelitis virus(VEEV). The time of addition studies indicated that lycorine functions at an early post-entry stage of CHIKV life cycle. The results based on two different CHIKV replicons provided further evidence that lycorine exerts its antiviral activity mainly by inhibiting CHIKV translation.Overall, our study extends the antiviral spectrum of lycorine.

Arbovirus and seizures

The high prevalence and spread of arthropod-borne viruses(arboviruses)make them an important cause of viral encephalitis in humans.Most epidemic viral encephalitides have an etiology associated with arboviruses.Among various arboviruses,the Japanese encephalitis virus,West Nile virus,Zika virus,Dengue virus and Chikungunya virus can induce seizures.Arboviruses of the genus Flavivirus are usually transmitted by mosquitoes and other host animals.These vector-borne pathogens can cause epidemic viral encephalitis.Seizures may not be the major manifestation in these viral encephalitides,but may predict a poor prognosis.In this article,we discuss the relationships between these viruses and seizures from perspectives of clinical characteristics,pathogenesis,prognosis and treatments of each.

Analysis of within-host CHIKV dynamics models with general incidence rate

In this paper we study the stability analysis of two within-host Chikungunya virus （CHIKV） dynamics models. The incidence rate between the CHIKV and the uninfected mouocytes is modeled by a general nonlinear function. The second model considers two types of infected monocytes （i） latently infected monocytes which do not generate CHIKV and （ii） actively infected monocytes which produce the CHIKV particles. Sufficient conditions are found which guarantee the global stability of the positive steady states. Using the Lyapunov function, we established the global stability of the steady states of the models. The theoretical results are confirmed by numerical simulations.

Structural Basis for Complementary and Alternative Medicine:Phytochemical Interaction with Non-Structural Protein 2 Protease-A Reverse Engineering Strategy

Objective： To understand the druggability of the bioactive compounds from traditional herbal formulations ＂Nilavembu Kudineer＂ and ＂Swasthya Raksha Amruta Peya＂ to heal chikungunya virus （CHIKV） infection. Methods： The efficiency of twenty novel chemical entities from ＂Nilavembu Kudineer＂ and ＂Swasthya Raksha Amruta Peya＂ to inhibit CHIKV infection in silico were evaluated. Ligands were prepared using Ligprep module of Schr0dinger. Active site was identified using SiteMap program. Grid box was generated using receptor grid generation wizard. Molecular docking was carried out using Grid Based Ligand Docking with Energetics （GLIDE） program. Results： Molecular docking studies showed that among twenty compounds, andrographoside, deoxyandrographoside, neoandrographolide, 14-deoxy-11-oxoandrographolide, butoxone and oleanolic acid showed GLIDE extra precision （XP） score of-9.10,-8.72, -8.25,-7.38,-7.28 and -7.01, respectively which were greater than or comparable with chloroquine （reference compound） XP score （-7.08） and were found to interact with the key residues GLLI 1043, LYS 1045, GLY 1176, LEU 1203, HIS 1222 and LYS 1239 which were characteristic functional unit crucial for replication of CHIKV. Conclusion： The binding affinity and the binding mode of chemical entities taken from herbal formulations with non-structural protein 2 protease were understood and our study provided a novel strategy in the development and design of drugs for CHIKV infection.