Biology subjects

Gulati, B. R.

Publications and source records attributed to Gulati, B. R..

7 recordsLinked to original sources

bioRxiv2025

Proteomic Profiling of Rabid Canine Brain Samples Reveals Dysregulation of Immune Signalling and Neuronal Pathways

Rabies is one of the most feared diseases and has been known to humans for approximately 4,000 years. It is caused by several lyssaviruses and leads to an encephalitis, which is 100% fatal after symptom onset. The most common cause of rabies is the rabies virus (RABV), which leads to around 59,000 human deaths globally every year. The infection leads to drastic changes in host behaviour, but the underlying mechanistic details remain unclear. Although interactions between the viral glycoprotein and host nicotinic acetylcholine receptors have been proposed as drivers of rabies-associated neurological dysfunction, clinical proteomic studies in naturally infected canines have been partially explored. In this study, we conducted a global proteomics analysis of RABV-infected and non-infected canine brain samples in India to unravel the changes in protein expression. Using liquid chromatography combined with mass spectrometry, we identified various host proteins and pathways dysregulated in the infected state. Approximately 700 proteins exhibited differential expression, with around 250 proteins involved in various pathways being significantly upregulated and approximately 500 proteins being significantly downregulated in the infected condition. Network clustering of the dysregulated proteins revealed functional modules, including clathrin-mediated endocytosis, actin cytoskeletal regulation, and the TCA cycle, indicating widespread alterations in cellular trafficking, energy metabolism, and structural integrity. Complementary pathway enrichment through PANTHER identified processes linked to axon guidance, integrin signalling, chemokine and cytokine-mediated inflammation, and cytoskeletal regulation, underscoring the profound impact of rabies virus infection on neuronal connectivity and host immune responses.

microbiology↗

bioRxiv2025

Multi-omics analysis uncovers differential growth kinetics of Japanese Encephalitis Virus in human and porcine macrophages

Japanese encephalitis virus (JEV), a mosquito-borne neurotropic virus, poses a significant threat to juvenile humans, while causing mild symptoms in pigs, except piglets. Pigs with high viremia are amplifier hosts, whereas humans with lower viremia are dead-end hosts. The molecular mechanisms behind the varying viremia levels in pigs and humans remain poorly understood. A comparative multi-omics study was conducted on JEV-infected macrophages, the early site of JEV replication in both species. We identified 24 key determinants potentially regulating viral growth. Functional validation of three antiviral factors - LGALS1, ssc-miR-133a-3p, and hsa-miR-3614-5p, and two proviral factors - MIF and VMP1, in macrophages showed that the upregulation of MIF and VMP1, and downregulation of ssc-miR-133a-3p, enhanced JEV replication in pigs. In contrast, the downregulation of MIF and VMP1 and upregulation of hsa-miR-3614-5p reduced JEV replication in human macrophages. These findings provide critical insights into JEV infection and its species-specific dynamics.

microbiology↗

bioRxiv2023

p38-MAPK is prerequisite for the synthesis of SARS-CoV-2 protein

The inhibition of p38 mitogen-activated protein kinase (p38-MAPK) by small molecule chemical inhibitors was previously shown to impair severe acute respiratory syndrome coronavirus 2 (SARS- CoV-2) replication, however, mechanisms underlying antiviral activity remains unexplored. In this study, reduced growth of SARS-CoV-2 in p38- knockout Vero cells, together with enhanced viral yield in cells transfected with construct expressing p38, suggested that p38-MAPK is essential for the propagation of SARS-CoV-2. The SARS-CoV-2 was also shown to induce phosphorylation (activation) of p38, at time when transcription/translational activities are considered to be at the peak levels. Further, we demonstrated that p38 supports viral RNA/protein synthesis without affecting viral attachment, entry, and budding in the target cells. In addition, we demonstrated that long-term culture of SARS-CoV-2 in the presence of p38 inhibitor SB203580 does not easily select resistant viral mutants. In conclusion, we provide mechanistic insights on the regulation of SARS-CoV-2 replication by p38 MAPK.

microbiology↗

bioRxiv2023

Unravelling Genomic Origin of Lumpy Skin Disease Virus in Recent Outbreaks

Lumpy skin disease virus (LSDV) belongs to the genus Capripox virus and family Poxviridae. LSDV was endemic in most of Africa, Middle east and Turkey, but since 2015, several outbreaks have been reported in Asian countries. In this study we used Whole Genome Sequence (WGS) approach to investigate the origin of the outbreak and understand the genomic landscape of the virus. Our study showed that the LSDV strain of 2022 outbreak exhibited many genetic variations, compared to the Reference Neethling strain sequence and the previous field strains from India. A total of 1819 variations were found in 22 genome sequences, which includes 399 extragenic mutations, 153 insertion frameshift mutations, 234 deletion frameshift mutations, 271 Single nucleotide polymorphisms (SNPs) and 762 silent SNPs. 38 genes have more than 2 variations per gene and these genes belong to viral-core protein, viral binding proteins, replication and RNA polymerase proteins. We highlight the importance of several SNPs in various genes which may play an essential role in pathogenesis of LSDV. Phylogenetic analysis performed on all whole genome sequences of LSDV showed two types of variants in India. One group of the variant with fewer mutations was found to lie closer to the LSDV 2019 strain from Ranchi while the other group clustered with previous Russian outbreaks from 2015. Our study highlights the importance of genomic characterization of viral outbreaks to not only monitor the frequency of mutations but also address its role in pathogenesis of LSDV as the outbreak continues.

microbiology↗

bioRxiv2022

Detection and Whole Genome of Japanese Encephalitis Virus Genotype III strains isolated from Indian Pig and Mosquito vector

Japanese encephalitis virus(JEV) are globally prevalent as deadly pathogens in human and animals including pig, horse and cattle. Japanese encephalitis (JE) still remains as an important cause of epidemic encephalitis worldwide and exists in a zoonotic transmission cycle. Assam is one of the highly endemic state for JE in India. In the present study, to understand the epidemiological status of JE circulating in pigs and mosquito particularly in Assam, India, molecular detection of JEV and the complete genome sequencing of the JEV isolates from pig and mosquito were done. The complete genome analysis of two JEV isolates from pig and mosquito were revealed7 and 21 numbers of unique points polymorphism of nucleotide during alignment of the sequences with other available sequences, respectively. Phylogenetic analysis revealed that the isolates of present investigation were belongs to genotype III and closely related with the strains of neighbouring country China. This study represents the transboundary nature of the JEV genotype III circulation and maintained the same genotype through mosquito-swine transmission cycles.

genomics↗

bioRxiv2021

hnRNPA1 regulates early translation to replication switch in SARS-CoV-2 life cycle

Our study suggests that methylation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA is essential for its optimal replication in the target cells. Heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1, an RNA-binding protein) was shown to mediate deposition of N6-methyladenosine (m6A) in internal SARS-CoV-2 RNA. The levels of hNRNPA1 expression and extent of methylation varied, depending on the course of SARS-CoV-2 life cycle. The recruitment of eIF4E (translational initiation factor) facilitated viral RNA translation at 1 hour post infection (1 hpi). However, at 2 hpi, methylation of internal SARS-CoV-2 RNA recruited hNRNPA1 which facilitated viral RNA transcription but resulted in translational repression, a phenomenon contributing in understanding the early translation to replication switch in the viral life cycle. Besides, the abrogation of methylation also produced a defective 5 cap of viral RNA which failed to interact with eIF4E, thereby resulting in a decreased synthesis of viral proteins. To conclude, methylation of the internal and 5 cap of SARS-CoV-2 RNA was shown to regulate transcription and translation of SARS-CoV-2 in a time dependent manner. IMPORTANCERNA modifications are found in all life forms and have been linked to development, health and diseases. Our study reveals that internal SARS-CoV-2 RNA methylation (m6A) is essential for interaction with hNRNPA1 to effectively synthesize viral genome. Besides, m6A-marked RNA and hRNPA1 interaction was also shown to regulate early translation to replication switch in SARS-CoV-2 life cycle. Blocking SARS-CoV-2 RNA methylation resulted in reduced virus yield, suggesting epitranscriptomic machinery (methylation) facilitates SARS-CoV-2 replication and might represent potential target for new antiviral drugs against COVID-19.

microbiology↗

bioRxiv2020

Emetine as an antiviral agent suppresses SARS-CoV-2 replication by inhibiting interaction of viral mRNA with eIF4E: An in vitro study

Emetine is a FDA-approved drug for the treatment of amebiasis. In the recent times we had also demonstrated the antiviral efficacy of emetine against some RNA and DNA viruses. Following emergence of the COVID-19, we further evaluated thein vitro antiviral activity of emetine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The therapeutic index of emetine was determined to be 10910.4, at a cytotoxic concentration 50 (CC50) of 1603.8 nM and effective concentration 50 (EC50) of 0.147 nM.Besides, we also demonstrated the protective efficacy of emetine against lethal challenge with infectious bronchitis virus (IBV; a chicken coronavirus) in the embryonated chicken egg infection model. Emetine treatment was shown to decrease viral RNA and protein synthesis without affecting other steps of viral life cycle such as attachment, entry and budding.In a chromatin immunoprecipitation (CHIP) assay, emetine was shown to disrupt the binding of SARS-CoV-2 RNA with eIF4E (eukaryotic translation initiation factor 4E, a cellular cap-binding protein required for initiation ofprotein translation). Further, SARS-CoV-2 was shown to exploit ERK/MNK1/eIF4E signalling pathwayfor its effective replication in the target cells. To conclude, emetine targets SARS-CoV-2 protein synthesis which is mediated via inhibiting the interaction of SARS-CoV-2 RNA with eIF4E. This is a novel mechanistic insight on the antiviral efficacy of emetine. In vitro antiviral efficacy against SARS-CoV-2 and its ability to protect chicken embryos against IBV suggests that emetine could be repurposed to treat COVID-19.

microbiology↗