Biology subjects

Ambikan, A. T.

Publications and source records attributed to Ambikan, A. T..

6 recordsLinked to original sources

bioRxiv2026

Integrated Clinical and Proteomic Precision Subgrouping for Severe Dengue Endotype Signature

BackgroundSevere dengue remains difficult to predict because patients with different clinical trajectories may present with overlapping features, and conventional severity classifications may not fully capture underlying biological heterogeneity. In this study, we applied an integrated clinical and proteomic endotyping approach to dissect dengue disease heterogeneity and identify molecular signatures associated with severity. MethodsPlasma proteomic profiles were analyzed together with detailed clinical, biochemical, hematological, coagulation, and immunological parameters from healthy controls and dengue patients classified according to WHO 2009 severity criteria. High-throughput proteomic analysis, unsupervised clustering, pathway enrichment, and machine-learning-based classification were used to identify dengue endotypes and define molecular features associated with predicted severe disease. ResultsIncreasing dengue severity was associated with progressive abnormalities in liver function, coagulation parameters, hematological indices, and inflammatory mediators, including IL-6, IL-15, HGF, and MUC-16. However, proteomic profiling revealed substantial overlap across conventional severity categories, indicating that clinical classification alone does not fully resolve dengue host-response heterogeneity. Integrated clinical-proteomic clustering identified distinct dengue endotypes, including a predicted severe endotype enriched for inflammatory, antiviral, and cytotoxic lymphocyte-associated pathways. This high-risk endotype was characterized by elevated IL-15, IFN-{gamma}, and granzymes, consistent with coordinated activation of cytotoxic lymphocyte-associated antiviral responses. Machine-learning analysis further showed that proteomic features were strong discriminators of this endotype, supporting their potential utility as biomarkers of severe host-response states. ConclusionIntegrated clinical-proteomic endotyping provides molecular resolution beyond conventional severity grading and identifies immune pathways associated with severe dengue. This framework may improve biological understanding of dengue progression and support future risk stratification and biomarker development.

systems biology↗

bioRxiv2026

ISG15-USP18 signaling restrains viperin-dependent metabolic antiviral restriction

Type I interferon (IFN-I) responses are tightly regulated to balance antiviral defense with cellular homeostasis. In humans, interferon-stimulated gene 15 (ISG15) functions as a critical negative regulator of IFN-I signaling by stabilizing the IFN negative regulator USP18, yet the functional consequences of ISG15 deficiency remain elusive. Here, we show that the loss of ISG15 exaggerates the JAK-STAT activation and, downstream, amplifies multiple ISGs including the nucleotide-modifying enzyme RSAD2 (viperin). Our quantitative proteomics, genetic reconstitution, and signaling analyses establish that defective USP18 stabilization skews the IFN response towards viperin expression. This amplified ISG network promotes viperin-catalyzed accumulation of the antiviral nucleotide analog ddhCTP, resulting in enhanced inhibition of viral RNA synthesis and the replication of Crimean-Congo hemorrhagic fever virus and SARS-CoV-2. Together, these findings demonstrate an ISG15-USP18-viperin axis that can be targeted to boost the metabolic antiviral restriction.

microbiology↗

bioRxiv2024

Parechovirus-3 infection disrupts immunometabolism and leads to glutamate excitotoxicity in neural organoids

Parechovirus ahumpari 3 (HPeV-3), is among the main agents causing severe neonatal neurological infections such as encephalitis and meningitis. However, the underlying molecular mechanisms and changes to the host cellular landscape leading to neurological disease has been understudied. Through quantitative proteomic analysis of HPeV-3 infected neural organoids, we identified unique metabolic changes following HPeV-3 infection that indicate immunometabolic dysregulation. Protein and pathway analyses showed significant alterations in neurotransmission and potentially, neuronal excitotoxicity. Elevated levels of extracellular glutamate, lactate dehydrogenase (LDH), and neurofilament light (NfL) confirmed glutamate excitotoxicity to be a key mechanism contributing to neuronal toxicity in HPeV-3 infection and can lead to apoptosis induced by caspase signaling. These insights are pivotal in delineating the metabolic landscape following severe HPeV-3 CNS infection and may identify potential host targets for therapeutic interventions.

neuroscience↗

bioRxiv2021

Implications of central carbon metabolism in SARS-CoV-2 replication and disease severity

Viruses hijack host metabolic pathways for their replicative advantage. Several observational trans-omics analyses associated carbon and amino acid metabolism in coronavirus disease 2019 (COVID-19) severity in patients but lacked mechanistic insights. In this study, using patient- derived multi-omics data and in vitro infection assays, we aimed to understand i) role of key metabolic pathways in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) reproduction and ii) its association with disease severity. Our data suggests that monocytes are key to the altered immune response during COVID-19. COVID-19 infection was associated with increased plasma glutamate levels, while glucose and mannose levels were determinants of the disease severity. Monocytes showed altered expression pattern of carbohydrate and amino acid transporters, GLUT1 and xCT respectively in severe COVID-19. Furthermore, lung epithelial cells (Calu-3) showed a strong acute metabolic adaptation following infection in vitro by modulating central carbon metabolism. We found that glycolysis and glutaminolysis are essential for virus replication and blocking these metabolic pathways caused significant reduction in virus production. Taken together, our study highlights that the virus utilizes and re-wires pathways governing central carbon metabolism leading to metabolic toxicity. Thus, the host metabolic perturbation could be an attractive strategy to limit the viral replication and disease severity.

microbiology↗

bioRxiv2020

Dysregulation in mTOR/HIF-1 signaling identified by proteo-transcriptomics of SARS-CoV-2 infected cells

How Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infections engage cellular host pathways and innate immunity in infected cells remain largely elusive. We performed an integrative proteo-transcriptomics analysis in SARS-CoV-2 infected HuH7 cells to map the cellular response to the invading virus over time. We identified four pathways, ErbB, HIF-1, mTOR and TNF signaling, among others that were markedly modulated during the course of the SARS-CoV-2 infection in vitro. Western blot validation of the downstream effector molecules of these pathways revealed a significant reduction in activated S6K1 and 4E-BP1 at 72 hours post infection. Unlike other human respiratory viruses, we found a significant inhibition of HIF-1 through the entire time course of the infection, suggesting a crosstalk between the SARS-CoV-2 and the mTOR/HIF-1 signaling. Further investigations are required to better understand the molecular sequelae in order to guide potential therapy in the management of severe COVID-19 patients.

microbiology↗

bioRxiv2018

Systemic inflammation following long-term successful antiretroviral therapy in people living with HIV (PLHIV)

The ART program in low- and middle-income countries (LMIC) like India, has a public health approach with the standardized regimen for all people living with HIV (PLHIV). Based on the evidence from high-income countries (HIC), the successful implication and scale-up of ART in India, the risk of an enhanced and accentuated onset of premature-aging or age-related diseases could be observed in PLHIV. However, very limited data is available on residual inflammation and immune activation in the populations who are on first-generation anti-HIV drugs like zidovudine and lamivudine that had more toxic side effects. Therefore, the aim of the present study was to evaluate the levels of systemic inflammation and understand the risk of age-associated diseases in PLHIV on long-term suppressive ART using a large number of biomarkers of the inflammation and immune activation. Blood samples were obtained from therapy naive PLHIV (Pre-ART, n=43), PLHIV on ART for >5 years (ART, n=53), and HIV-negative healthy controls (HIVNC, n=41). Samples were analyzed for 92 markers of inflammation, sCD14, sCD163, and telomere length. Several statistical tests were performed to compare the groups under study. Multivariate linear regression was used to investigate the associations. Despite a median duration of eight years of successful ART, sCD14 (p<0.001) and sCD163 (p=0.04) levels continued to be significantly elevated in ART group as compared to HIVNC. Eleven inflammatory markers, including 4E-BP1, ADA, CCL23, CD5, CD8A, CST5, MMP1, NT3, SLAMF1, TRAIL and TRANCE, were found to be significantly different (p<0.05) between the groups. Many of these markers are associated with age-related co-morbidities including cardiovascular disease, neurocognitive decline and some of these markers are being reported for the first time in the context of HIV-induced inflammation. Linear regression analysis showed a significant negative association between HIV-1-positivity and telomere length (p<0.0001). In ART-group CXCL1 (p=0.048) and TGF- (p=0.026) have a significant association with increased telomere length and IL-10RA was significantly associated with decreased telomere length (p=0.042). This observation warrants further mechanistic studies to generate evidence to highlight the need for enhanced treatment monitoring and special interventions in HIV-infected individuals.

immunology↗