Molecular Testing in Stage 4 Stomach Cancer in India: A Single-Centre Experience.

Introduction Advanced gastric cancer (GC) has a very poor prognosis, and chemotherapy has been the standard of care. The use of immunotherapy or targeted therapy in the stage 4 setting is dependent on molecular testing of the tumour. There is a paucity of data in the Indian scenario on testing for molecular markers in stage 4 GC. Therefore, in this study, we looked at the prevalence of human epidermal growth factor receptor 2 (HER2/neu) expression/amplification, deficient mismatch repair (d-MMR)/microsatellite instability (MSI) high status, and programmed death ligand 1 (PDL-1) status in stage 4 gastric/gastroesophageal junction (GEJ) adenocarcinoma. Methods A retrospective single-centre observational study was conducted between January 2017 and January 2022 of patients diagnosed with stage 4 GC/GEJ adenocarcinoma. Patient data were collected from stored electronic patient records. Data on stage 4 patients who underwent testing for HER2/neu, mismatch repair (MMR)/MSI, and PDL-1 status were recorded. Treatment received was also noted. Results During the study period, 139 patients were diagnosed with stage 4 GC/GEJ adenocarcinoma. HER2/neu testing was done in 99 stage 4 patients (71.2%), with a positivity rate of 16.16% (n = 16). All patients diagnosed as HER2/neu-positive were treated with trastuzumab. Testing of MMR status was carried out in 91 stage 4 patients (65.4%). d-MMR/MSI high was detected in eight patients (8.8%), of which germline MMR was detected as positive in one patient. Five of these eight patients (62.5%) received immune checkpoint inhibitors. PDL-1 testing was done in 61 of the 139 stage 4 patients (43.9%). Twenty patients (32.7%) had PDL-1 tumour proportion score > 1%/combined positive score > 1. Conclusion Molecular profiling has now become the standard while treating late-stage GC. HER2/neu-positive patients have improved survival due to the use of anti-HER2/neu-targeted therapies. It is important to look at not only PDL-1 but also MMR to identify patients who would be eligible and benefit from immunotherapy.

Corrigendum: Drug repurposing approach against chikungunya virus: an in vitro and in silico study.

[This corrects the article DOI: 10.3389/fcimb.2023.1132538.].

Drug repurposing approach against chikungunya virus: an in vitro and in silico study.

The chikungunya virus (CHIKV) is an alphavirus transmitted by Aedes mosquitoes. There are no licenced antivirals or vaccines for treatment or prevention. Drug repurposing approach has emerged as a novel concept to find alternative uses of therapeutics to battle pathogens. In the present study, anti CHIKV activity of fourteen FDA-approved drugs was investigated by in vitro and in silico approaches. Focus-forming unit assay, immunofluorescence test, and quantitative RT-PCR assay were used to assess the in vitro inhibitory effect of these drugs against CHIKV in Vero CCL-81 cells. The findings showed that nine compounds, viz., temsirolimus, 2-fluoroadenine, doxorubicin, felbinac, emetine, lomibuvir, enalaprilat, metyrapone and resveratrol exhibit anti chikungunya activity. Furthermore, in silico molecular docking studies performed by targeting CHIKV structural and non-structural proteins revealed that these drugs can bind to structural protein targets such as envelope protein, and capsid, and non-structural proteins NSP2, NSP3 and NSP4 (RdRp). Findings from in vitro and in silico studies reveal that these drugs can suppress the infection and replication of CHIKV and further in vivo studies followed by clinical trials are warranted.

Anti-Dengue Activity of Lipophilic Fraction of Ocimum basilicum L. Stem.

Ocimum basilicum L. is used to cure many types of fever in traditional medicine. This study aims to explore the antiviral activity of the lipophilic fraction of the stem of O. basilicum (LFOB) against dengue virus (DENV) and chikungunya virus (CHIKV). The LFOB was analyzed using GC-FID and GC-MS. The antiviral activity of LFOB was studied using the Vero CCL-81 cell line. The cytotoxicity assay was performed using 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). In vitro antiviral activity and FFU assay were used to determine and confirm antiviral activity against DENV and CHIKV. Twenty-six compounds were identified in LFOB using GC/MS. The most abundant compounds were ß-sitosterol (22.9%), stigmasterol (18.7%), and campesterol (12.9%). Significant reduction in DENV titre was observed under pre- and post-infection treatment conditions at a concentration of 3.125 µg/mL, but no anti-CHIKV activity was observed. Our earlier and the present AutoDock-Vina-based in silico docking study revealed that ß-sitosterol and stigmasterol could form strong interactions with the DENV E glycoprotein and DENV RdRp domain, respectively. Our findings suggest that LFOB can inhibit DENV infection and might act as a potent prophylactic/therapeutic agent against DENV-2. In silico results suggested that ß-sitosterol and stigmasterol may block the viral entry by inhibiting the fusion process and viral replication respectively.

Nanostructured Etodolac Carriers in Transdermal Gel: Optimization and Characterization.

AIMS: To optimize, formulate, and evaluate a Nanostructured Lipid Carrier (NLC) based transdermal gel of Etodolac (ETD). OBJECTIVE: To avoid issues of conventional route ETD administration like first pass metabolism, gastric ulceration, hemorrhage, and being a class-II drug with less solubility. A transdermal gel of nanostructured lipid carrier for ETD has been developed. Formulation will execute faster onset of action, increased penetration, permeation with extended release of the drug for a longer duration. METHODS: A central composite 32 factorial design is used to plan experiments. NLCs are prepared by the method of melt emulsification and ultrasonication. Compritol 888ATO and Miglyol are used as solid and liquid lipid phases. Surfactant Pluronic F68 showed a significant effect on particle size, entrapment efficiency, and drug release. Particle size characterized using photon correlation spectroscopy and scanning electron microscopy. Cumulative drug release studied using an artificial diffusion cell and a dialysis membrane. A skin permeation study was performed using goat skin at 32°C ± 0.5°C. The efficacy of the NLC gel was verified using a pharmacodynamic study followed by stability study for 3 and 6 months. RESULTS: The optimized batch of ETD NLC found spherical with a 241.3 nm particle size with 0.392 PDI,-29 mV zeta potential. Entrapment efficiency and cumulative drug release were found to be 64.21 ± 1.23% and 70.12 ± 2.10% (after 12 hours), respectively. All batches followed zeroorder drug release kinetics and non-Fickian (Super Case II transport) with 0.1619 mg/cm2/hr transdermal flux. The NLC gel of ETD showed a quick onset and lengthened therapeutic activity until 24 hours compared to the micellar ETD gel. CONCLUSION: Etodolac NLC batch successfully optimized using central composite design. The relationships between the components of the NLC-total lipid:drug and surfactant-and the outcomes- particle size,%entrapment and% drug release-were better understood by examining several contour plots. The results of the experimental and predicted formulations were found to be in good agreement with slight bias, demonstrating the reliability of the optimization process.

Effect of Sauropus androgynus L. Merr. on dengue virus-2: An in vitro and in silico study.

ETHNOPHARMACOLOGICAL RELEVANCE: Sauropus androgynus L. Merr. (Euphorbiaceae) commonly known as "multigreen" and "multivitamin" is consumed as a vegetable and used in traditional medicine to relieve fever. AIM OF THE STUDY: This in vitro study is aimed to explore the activities of the lipophilic fraction of the leaves of S. androgynus (LFSA) against dengue (DENV), chikungunya (CHIKV) viruses and malaria (P. falciparum strain 3D7) parasite. MATERIALS AND METHODS: The LFSA was analyzed by using GC-FID and GC-MS. The antiviral activity of LFSA was studied using the Vero CCL-81 cell line. The cytotoxicity assay was performed using 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). Focus forming unit (FFU), cell-based immunofluorescence (IFA) assays, and quantitative RT-PCR, were used to determine and confirm antiviral activity against DENV and CHIKV. The antiparasitic activity of LFSA was carried out against P. falciparum strain 3D7 grown in fresh O+ human erythrocytes culture. RESULTS: Twelve compounds were identified in LFSA using GC/MS. The most abundant compound was squalene (36.9%), followed by vitamin E (12.5%) and linolenic acid (10.2%). Significant reduction in DENV titre was observed under pre- and post-infection treatment conditions at a concentration of 31.25 µg/ml, but no anti-malarial and anti-CHIKV activity was observed. The Autodock-Vina-based in-silico docking study revealed that ß-sitosterol could form a strong interaction with the DENV E glycoprotein. CONCLUSION: Our findings suggest that LFSA can inhibit DENV infection and might act as a potent prophylactic/therapeutic agent against DENV-2. In-silico results suggested that ß-sitosterol may block the viral entry by inhibiting the fusion process.

Deciphering the Role of Pyroptosis Impact on Cardiovascular Diseases.

Pyroptosis has become a noteworthy area of focus in recent years due to its association with inflammatory diseases. Pyroptosis is a type of programmed cell death accompanied by an inflammatory response, and the discovery of the gasdermin family has expanded the study of pyroptosis. The primary characteristics of pyroptosis include cell expansion, membrane penetration, and the ejection of cell contents. In healthy physiology, pyroptosis is an essential part of the host's defence against pathogen infection. Excessive Pyroptosis, however, can lead to unchecked and persistent inflammatory responses, including the emergence of inflammatory diseases. More precisely, gasdermin family members have a role in the creation of membrane holes during pyroptosis, which leads to cell lysis. It is also related to how pro-inflammatory intracellular substances, including IL-1, IL-18, and High mobility group box 1 (HMGB1), are used. Two different signalling pathways, one of which is regulated by caspase-1 and the other by caspase-4/5/11, are the primary causes of pyroptosis. Cardiovascular diseases are often associated with cell death and acute or chronic inflammation, making this area of research particularly relevant. In this review, we first systematically summarize recent findings related to Pyroptosis, exploring its characteristics and the signalling pathway mechanisms, as well as various treatment strategies based on its modulation that has emerged from the studies. Some of these strategies are currently undergoing clinical trials. Additionally, the article elaborates on the scientific evidence indicating the role of Pyroptosis in various cardiovascular diseases. As a whole, this should shed insight into future paths and present innovative ideas for employing Pyroptosis as a strong disease-fighting weapon.

Real-World Experience with Nivolumab in Metastatic Renal Cell Carcinoma Patients Who Have Progressed on Prior Therapies: A Single-Center Study from India.

Amit RauthanIntroduction Nivolumab monotherapy is approved for the treatment of metastatic renal cell carcinoma (mRCC) patients who have progressed on prior therapies based on the pivotal Checkmate-025 trial. There is limited literature on the efficacy and safety profile of usage of nivolumab in the treatment of mRCC in India in a real-world setting. Methods A retrospective analysis was performed of patients who received nivolumab monotherapy for mRCC after having progressed on prior therapies. Tumor response was graded according to RECIST v1.1 and Kaplan-Meier survival analysis was used to estimate progression-free survival (PFS) and overall survival (OS). Immune-related adverse events (irAEs) were documented and graded according to CTCAE v5.0. Results Between 2016 and 2019, 35 patients received nivolumab for mRCC at our center after progression on prior therapies. A majority of the patients ( n = 30, 85.7%) received it in a second-line setting, and the remaining in the third line and beyond setting. Clear cell was the most common histology ( n = 26, 74.3%). There were 18 patients (51.42%) who belonged to IMDC intermediate risk, while 17 (48.58%) patients were at poor risk. The overall response rate was 60%, with complete response (CR) in 11.4%. Median duration of response was not reached among responders. Median PFS was 5 months (95% confidence interval [CI]: 3.06-6.93) and median OS was 26 months (95% CI: 1.90-50.09). Ongoing survival of 47, 42, 34, and 22 months was noted in four patients with CR, respectively. In our study, 23 patients (65.71%) experienced any grade of irAE. Grade 3 irAEs was seen in four patients (11.42%). Most common irAE was thyroid dysfunction seen in 12 patients (34.2%). Treatment discontinuation due to irAEs occurred in three patients (8.57%). Conclusion Nivolumab showed good efficacy with high response rates and an OS comparable to the pivotal Checkmate-025 trial. It was well tolerated with safety profile in terms of irAE consistent with those reported in literature.

A Transcriptomics-Based Bioinformatics Approach for Identification and In Vitro Screening of FDA-Approved Drugs for Repurposing against Dengue Virus-2.

The rising incidence of dengue virus (DENV) infections in the tropical and sub-tropical regions of the world emphasizes the need to identify effective therapeutic drugs against the disease. Repurposing of drugs has emerged as a novel concept to combat pathogens. In this study, we employed a transcriptomics-based bioinformatics approach for drug identification against DENV. Gene expression omnibus datasets from patients with different grades of dengue disease severity and healthy controls were used to identify differentially expressed genes in dengue cases, which were then applied to the query tool of Connectivity Map to identify the inverse gene-disease-drug relationship. A total of sixteen identified drugs were investigated for their prophylactic, virucidal, and therapeutic effects against DENV. Focus-forming unit assay and quantitative RT-PCR were used to evaluate the antiviral activity. Results revealed that five compounds, viz., resveratrol, doxorubicin, lomibuvir, elvitegravir, and enalaprilat, have significant anti-DENV activity. Further, molecular docking studies showed that these drugs can interact with a variety of protein targets of DENV, including the glycoprotein, the NS5 RdRp, NS2B-NS3 protease, and NS5 methyltransferase The in vitro and in silico results, therefore, reveal that these drugs have the ability to decrease DENV-2 production, suggesting that these drugs or their derivatives could be attempted as therapeutic agents against DENV infections.

An Overview of the Impact of Body Mass Index on Pathological Complete Response Following Neoadjuvant Chemotherapy in Operable Breast Cancer in a Tertiary Care Centre in South India.

Objective: The incidence of female breast cancer in the world is 11.7% with a mortality rate of 6.9%. According to Globocon 2020, breast cancer is the most commonly diagnosed cancer (24.5%) and the leading cause of cancer-related death amongst women worldwide. The purpose of this study was to analyze the impact of Body Mass Index (BMI) on pathological complete response (pCR) rates for operable breast cancer after neoadjuvant chemotherapy (NACT). The primary endpoint was to assess histopathological features of the surgical specimen in response to NACT and to investigate the relationship with pre-chemotherapy BMI taking into account the various molecular subtypes of breast cancer. Materials and Methods: Patients with biopsy-proven breast carcinoma who underwent surgery after NACT between January 2017 and May 2021 were included. All patients were initially divided into three groups depending on their pre-chemotherapy BMI. With BMI <22.9 as normal or underweight category, BMI of 23-27.4, was taken as overweight category and BMI ≥27.5 as obese category. Results: The study included 184 patients. Normal weight patients had the highest rate of pCR (75%) and the lowest was seen in the obese category (33.75%). Furthermore, the subtype most likely to achieve pCR was HER2+/ER negative followed by triple negative BC with odds ratios of 3.46 and 2.21, respectively. Conclusion: This retrospective study established that overweight and obese patients suffering from breast carcinoma had a lessened pCR rate following NACT in comparison with those who were under-/normal weight.

Studies on the antiviral activity of chebulinic acid against dengue and chikungunya viruses and in silico investigation of its mechanism of inhibition.

Chebulinic acid (CA), originally isolated from the flower extract of the plant Terminalia chebula, has been shown to inhibit infection of herpes simplex virus-2 (HSV-2), suggestively by inhibiting the host entry step of viral infection. Like HSV-2, the dengue virus (DENV) and chikungunya virus (CHIKV) also use receptor glycosaminoglycans (GAG) to gain host entry, therefore, the activity of CA was tested against these viruses. Co-treatment of 8 µM CA with DENV-2 caused 2 log decrease in the virus titer (4.0 log10FFU/mL) at 120 h post infection, compared to virus control (5.95 log10FFU/mL). In contrast, no inhibitory effect of CA was observed against CHIKV infection under any condition. The mechanism of action of CA was investigated in silico by employing DENV-2 and CHIKV envelope glycoproteins. During docking, CA demonstrated equivalent binding at multiple sites on DENV-2 envelope protein, including GAG binding site, which have previously been reported to play a crucial role in host attachment and fusion, indicating blocking of these sites. However, CA did not show binding to the GAG binding site on envelope protein-2 of CHIKV. The in vitro and in silico findings suggest that CA possesses the ability to inhibit DENV-2 infection at the entry stage of its infection cycle and may be developed as a potential therapeutic agent against it.

In Vitro Antiviral Activity of Potential Medicinal Plant Extracts Against Dengue and Chikungunya Viruses.

Dengue and chikungunya are two important mosquito-borne infections which are known to occur extensively in tropical and subtropical areas. Presently, there is no treatment for these viral diseases. In vitro antiviral screening of 25 extracts prepared from the plants of Vitex negundo, Plumeria alba, Ancistrocladus heyneanus, Bacopa monnieri, Anacardium occidentale, Cucurbita maxima, Simarouba glauca, and Embelia ribes using different solvents and four purified compounds (anacardic acid, chloroquinone, glaucarubinone, and methyl gallate) were carried out for their anti-dengue virus (DENV) and anti-chikungunya virus (CHIKV) activities. Maximum nontoxic concentrations of the chloroform, methanol, ethyl acetate, petroleum ether, dichloromethane, and hydroalcoholic extracts of eight plants were used. The antiviral activity was assessed by focus-forming unit assay, quantitative real-time RT-PCR, and immunofluorescence assays. Extracts from Plumeria alba, Ancistrocladus heyneanus, Bacopa monnieri, and Cucurbita maxima showed both anti-DENV and CHIKV activity while extract from Vitex negundo showed only anti-DENV activity. Among the purified compounds, anacardic acid, chloroquinone and methyl gallate showed anti-dengue activity while only methyl gallate had anti-chikungunya activity. The present study had identified the plant extracts with anti-dengue and anti-chikungunya activities, and these extracts can be further characterized for finding effective phytopharmaceutical drugs against dengue and chikungunya.

Effect of Cationic Lipid Nanoparticle Loaded siRNA with Stearylamine against Chikungunya Virus.

Chikungunya is an infectious disease caused by mosquito-transmitted chikungunya virus (CHIKV). It was reported that NS1 and E2 siRNAs administration demonstrated CHIKV inhibition in in vitro as well as in vivo systems. Cationic lipids are promising for designing safe non-viral vectors and are beneficial in treating chikungunya. In this study, nanodelivery systems (hybrid polymeric/solid lipid nanoparticles) using cationic lipids (stearylamine, C9 lipid, and dioctadecylamine) and polymers (branched PEI-g-PEG -PEG) were prepared, characterized, and complexed with siRNA. The four developed delivery systems (F1, F2, F3, and F4) were assessed for stability and potential toxicities against CHIKV. In comparison to the other nanodelivery systems, F4 containing stearylamine (Octadecylamine; ODA), with an induced optimum cationic charge of 45.7 mV in the range of 152.1 nm, allowed maximum siRNA complexation, better stability, and higher transfection, with strong inhibition against the E2 and NS1 genes of CHIKV. The study concludes that cationic lipid-like ODA with ease of synthesis and characterization showed maximum complexation by structural condensation of siRNA owing to high transfection alone. Synergistic inhibition of CHIKV along with siRNA was demonstrated in both in vitro and in vivo models. Therefore, ODA-based cationic lipid nanoparticles can be explored as safe, potent, and efficient nonviral vectors overcoming siRNA in vivo complexities against chikungunya.

Design and synthesis of novel spirocyclic carboxylic acids as potent and orally bioavailable DGAT1 inhibitors and their biological evaluation.

A series of novel spirocyclic DGAT1 inhibitors containing the oxadiazole motif were designed and synthesized for biological evaluation. Several compounds exhibited potent diacylglycerol acyltransferase 1 (DGAT1) inhibitory activity. Optimization of the series led to the identification of five lead compounds 8, 9, 10, 11 and 12 that showed excellent in-vitro activity with IC50 values ranging from 7 to 20 nM against human DGAT1. All compounds demonstrated good druggability as well as microsomal stability and safety profiles such as hERG and CYP. Compound 12 significantly reduced plasma triglyceride levels in-vivo in the mouse model of acute lipid challenge. Significant reduction in plasma TG excursion was observed, thus indicating DGAT1 inhibition in-vivo.

Targeted in vitro gene silencing of E2 and nsP1 genes of chikungunya virus by biocompatible zeolitic imidazolate framework.

Chikungunya fever caused by the mosquito-transmitted chikungunya virus (CHIKV) is a major public health concern in tropical, sub-tropical and temperate climatic regions. The lack of any licensed vaccine or antiviral agents against CHIKV warrants the development of effective antiviral therapies. Small interfering RNA (siRNA) mediated gene silencing of CHIKV structural and non-structural genes serves as a potential antiviral strategy. The therapeutic efficiency of siRNA can be improved by using an efficient delivery system. Metal-organic framework biocomposits have demonstrated an exceptional capability in protecting and efficiently delivering nucleic acids into cells. In the present study, carbonated ZIF called ZIF-C has been utilized to deliver siRNAs targeted against E2 and nsP1 genes of CHIKV to achieve a reduction in viral replication and infectivity. Cellular transfection studies of E2 and nsP1 genes targeting free siRNAs and ZIF-C encapsulated siRNAs in CHIKV infected Vero CCL-81 cells were performed. Our results reveal a significant reduction of infectious virus titre, viral RNA levels and percent of infected cells in cultures transfected with ZIF-C encapsulated siRNA compared to cells transfected with free siRNA. The results suggest that delivery of siRNA through ZIF-C enhances the antiviral activity of CHIKV E2 and nsP1 genes directed siRNAs.

In Vitro Antiviral Activity of α-Mangostin against Dengue Virus Serotype-2 (DENV-2).

Dengue virus (DENV), a member of the family Flaviviridae, is a threat for global health as it infects more than 100 million people yearly. Approved antiviral therapies or vaccines for the treatment or prevention of DENV infections are not available. In the present study, natural compounds were screened for their antiviral activity against DENV by in vitro cell line-based assay. α-Mangostin, a xanthanoid, was observed to exert antiviral activity against DENV-2 under pre-, co- and post-treatment testing conditions. The antiviral activity was determined by foci forming unit (FFU) assay, quantitative RT-PCR and cell-based immunofluorescence assay (IFA). A complete inhibition of DENV-2 was observed at 8 µM under the co-treatment condition. The possible inhibitory mechanism of α-Mangostin was also determined by docking studies. The molecular docking experiments indicate that α-Mangostin can interact with multiple DENV protein targets such as the NS5 methyltransferase, NS2B-NS3 protease and the glycoprotein E. The in vitro and in silico findings suggest that α-Mangostin possesses the ability to suppress DENV-2 production at different stages of its replication cycle and might act as a prophylactic/therapeutic agent against DENV-2.

In vitro and in vivo studies reveal α-Mangostin, a xanthonoid from Garcinia mangostana, as a promising natural antiviral compound against chikungunya virus.

BACKGROUND: Chikungunya virus (CHIKV), a serious health problem in several tropical countries, is the causative agent of chikungunya fever. Approved antiviral therapies or vaccines for the treatment or prevention of CHIKV infections are not available. As diverse natural phenolic compounds have been shown to possess antiviral activities, we explored the antiviral activity of α-Mangostin, a xanthanoid, against CHIKV infection. METHODS: The in vitro prophylactic and therapeutic effects of α-Mangostin on CHIKV replication in Vero E6 cells were investigated by administering it under pre, post and cotreatment conditions. The antiviral activity was determined by foci forming unit assay, quantitative RT-PCR and cell-based immune-fluorescence assay. The molecular mechanism of inhibitory action was further proposed using in silico molecular docking studies. RESULTS: In vitro studies revealed that 8 µM α-Mangostin completely inhibited CHIKV infectivity under the cotreatment condition. CHIKV replication was also inhibited in virus-infected mice. This is the first in vivo study which clearly showed that α-Mangostin is effective in vivo by significantly reducing virus replication in serum and muscles. Molecular docking indicated that α-Mangostin can efficiently interact with the E2-E1 heterodimeric glycoprotein and the ADP-ribose binding cavity of the nsP3 macrodomain. CONCLUSIONS: The findings suggest that α-Mangostin can inhibit CHIKV infection and replication through possible interaction with multiple CHIKV target proteins and might act as a prophylactic/therapeutic agent against CHIKV.

Antiviral activity of stearylamine against chikungunya virus.

Chikungunya, a mosquito-borne disease that causes high fever and severe joint pain in humans, is a profound global threat because of its high rate of contagion and lack of antiviral interventions or vaccines for controlling the infection. The present study was aimed to investigate the antiviral activity of Stearylamine (SA) against Chikungunya virus (CHIKV) in both in vitro and in vivo. The antiviral activity of SA was determined by foci forming unit (FFU) assay, quantitative RT-PCR and cell-based immune-fluorescence assay (IFA). Further in vivo studies were carried out to see the effect of SA treatment in CHIKV infected C57BL/6 mice. The anti-CHIKV activity was evaluated using qRT-PCR in serum and muscle tissues at different time points and by histopathology. In vitro treatment with SA at a concentration of 50 µM showed a reduction of 1.23 ± 0.19 log10 FFU/mL at 16 h and 1.56 ± 0.12 log10 FFU/mL at 24 h posttreatment by FFU assay. qRT-PCR studies indicated that SA treatment at 50µM concentration showed a singnificant reduction of 1.6 ± 0.1 log10 and 1.27 ± 0.12 log10 RNA copies when compared with that of virus control at 16 and 24 h post incubation. Treatments in the C57BL/6 mice model revealed that SA at 20 mg/kg dose per day up to 3, 5 and 7 days, produced stronger inhibition against CHIKV indicating substantially decrease viral loads and inflammatory cell migration in comparison to a dose of 10 mg/kg. This first in vivo study clearly indicates that SA is effective by significantly reducing virus replication in serum and muscles. As a next-generation antiviral therapeutic, these promising results can be translated for the use of SA to rationalize and develop an ideal delivery system alone or in combination against CHIKV.

An in vitro refolding method to produce oligomers of anti-CHIKV, E2-IgM Fc fusion subunit vaccine candidates expressed in E. coli.

Recombinant envelope protein-1 (E1) and E2 of Chikungunya virus (CHIKV) has been shown to elicit neutralizing antibodies and a balanced Th1/Th2 response in mice however with limited protection. Recently reported CHIK virus-like particles showed augmented immunity and protection in adult mice in comparison to E1 and E2, however exacerbated the disease in aged subjects. In order to improve the overall efficacy of protein based vaccines, novel strategies need to be adopted. The discovery of IgM Fc receptor (FcµR) and its role in humoral immune response led us to hypothesise that fusion of an antigen with Fc of IgM may enhance its immunogenicity by polymerizing it and FcµR mediated activation of B and other immune cells. We report in the current study, expression of E2 subunit of CHIKV in fusion with various IgM Fc domains/peptides in E. coli, their in-vitro refolding, characterization and immune response in C57BL/6 mice. Candidates fused with CH3-CH4 Fc fragment produced stable oligomers, whereas the one fused with peptides remained monomeric. The latter elicited a strong humoral and a balanced Th1/Th2 response in mice, whereas the polymeric candidate despite eliciting a strong humoral response, stimulated a biased Th1 response and exhibited higher virus neutralization in Vero cells.