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Filipovic, I.

Publications and source records attributed to Filipovic, I..

14 recordsLinked to original sources

The mitochondrial transaminase GOT2 supports Japanese encephalitis virus replication in neuronal cells

Japanese encephalitis virus (JEV) is the leading cause of viral encephalitis in Asia, yet the host pathways that sustain its replication in the central nervous system remain poorly defined, and no antiviral therapies exist. Here we combine time-resolved transcriptomics and proteomics in mouse neuroblastoma (Neuro-2a) cells with time-resolved proteomics of infected mouse brain, integrated using directionality-penalized p-value merging. JEV infection was accompanied by progressive induction of interferon-stimulated proteins and by changes in the abundance of enzymes of central carbon and energy metabolism, spanning the tricarboxylic acid cycle, glycolysis, oxidative phosphorylation and glutaminolysis. Temporal clustering of the brain proteome linked oxidative phosphorylation remodelling to a dependence on glutamine metabolism. Glutamine antagonism with DON reduced viral RNA, whereas glycolytic inhibition and AKT modulation did not significantly alter it under the conditions tested. Silencing of the mitochondrial transaminase GOT2 reduced JEV RNA, viral protein, and infectious virus production in human SH-SY5Y cells. Our findings identify a glutamine-GOT2 axis as a metabolic dependency of JEV and a candidate host-directed antiviral target.

microbiology↗

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↗

IFN-driven lipid synthesis shutdown in CD4⁺ T cells during acute SIV infection and persistent OXPHOS with ART initiation

Cellular metabolism regulates HIV/SIV replication and reservoir establishment, yet how infection and antiretroviral therapy initiation (ARTi) shape CD4 T cell metabolism in vivo remains poorly defined. Using the SIVmac239 macaque model, we integrated single-cell metabolic profiling (MIST), transcriptomics, lipidomics and genome-scale metabolic modeling to characterize their metabolic remodeling. At peak viremia, CD4 T cells exhibited shutdown of de novo fatty-acid (FA) synthesis, reflected by acetyl-CoA carboxylase-1 (ACC1) downregulation, inhibition of lipid-anabolic reactions, and depletion of membrane phospholipids. This state was driven by type I interferon (IFN-I) responses, and IFN-I suppressed ACC1 in vitro. Pharmacologic inhibition of FA synthesis enhanced T cell activation and exerted direct antiviral effects. Following ARTi, most metabolic pathways in CD4+ T cells were suppressed, whereas oxidative phosphorylation (OXPHOS) remained elevated and its levels in effector memory cells correlated with cell-associated-vDNA These findings identify IFN-driven FA synthesis suppression as a novel effector mechanism during acute viral infection, and persistent OXPHOS in effector CD4 T cells as a metabolic correlate of early reservoir establishment.

immunology↗

Spatial close-kin mark-recapture methods to estimate dispersal parameters and barrier strength for mosquitoes

Close-kin mark-recapture (CKMR) methods have recently been used to infer demographic parameters for several aquatic and terrestrial species. For mosquitoes, the spatial distribution of close-kin pairs has been used to estimate mean dispersal distance, of relevance to vector-borne disease transmission and genetic biocontrol strategies. Close-kin methods have advantages over traditional mark-release-recapture (MRR) methods as the mark is genetic, removing the need for physical marking and recapturing that may interfere with movement behavior. Here, we extend CKMR methods to accommodate spatial structure alongside life history for mosquitoes and comparable insects. We derive kinship probabilities for parent-offspring and full-sibling pairs in a spatial context, where an individual in each pair may be a larva or adult. Using the dengue vector Aedes aegypti as a case study, we use an individual-based model of mosquito life history to test the effectiveness of this approach at estimating parameters such as mean dispersal distance, daily staying probability, and the strength of a barrier to movement. Considering a simulated population of 9,025 adult mosquitoes arranged on a 19-by-19 grid, we find the CKMR approach provides unbiased and precise estimates of mean dispersal distance given a total of 2,500 adult females sampled over a three-month period using 25 traps evenly spread throughout the landscape. The CKMR approach is also able to estimate parameters of more complex dispersal kernels, such as the daily staying probability of a zero-inflated exponential kernel, or the strength of a barrier to movement, provided the magnitude of these parameters is greater than 0.5. These results suggest that CKMR provides an insightful characterization of mosquito dispersal that is complementary to conventional MRR methods. Author summaryClose-kin mark-recapture (CKMR) is a genetic analogue of mark-release-recapture (MRR) in which the frequency of marked individuals in a sample is used to infer demographic parameters such as census population size and mean dispersal distance. These methods have been widely applied to aquatic species; however their application to mosquitoes is yet to be rigorously explored. Previous theoretical work demonstrated the potential for CKMR to infer parameters such as population size and mortality rate for randomly-mixing mosquito populations, and close-kin-based methods have been used to infer movement patterns for Aedes aegypti mosquitoes in Singapore and Malaysia. Here, we use simulations to explore the potential for formal CKMR methods to characterize mosquito dispersal patterns. We find that formal CKMR methods are able to accurately estimate mean dispersal distance, and to estimate additional parameters, such as the strength of a landscape barrier and the probability that a mosquito remains within its population node each day. CKMR and other close-kin-based methods provide insights into mosquito dispersal complementary to commonly-used alternatives such as MRR, as they capture displacement across several generations and are not compromised by the marking process.

ecology↗

Finding divergent sequences of homomorphic sex chromosomes via diploidized nanopore-based assembly from a single male

Although homomorphic sex chromosomes can have non-recombining regions with elevated sequence divergence between its complements, such divergence signals can be difficult to detect bioinformatically. If found in genomes of e.g. insect pests, these sequences could be targeted by the engineered genetic sexing and control systems. Here, we report an approach that can leverage long-read nanopore sequencing of a single XY male to identify divergent regions of homomorphic sex chromosomes. Long-read data are used for de novo genome assembly that is diploidized in a way that maximizes sex-specific differences between its haploid complements. We show that the correct assembly phasing is supported by the mapping of nanopore reads from the males haploid Y-bearing sperm cells. The approach revealed a highly divergent region (HDR) near the centromere of the homomorphic sex chromosome of Aedes aegypti, the most important arboviral vector, for which there is a great interest in creating new genetic control tools. HDR is located [~]5Mb downstream of the known male-determining locus on chromosome 1 and is significantly enriched for ovary-biased genes. While recombination in HDR ceased relatively recently ([~]1.4 MYA), HDR gametologs have divergent exons and introns of protein coding genes, and most lncRNA genes became X-specific. Megabases of previously invisible sex-linked sequences provide new putative targets for engineering the genetic systems to control this deadly mosquito. Broadly, our approach expands the toolbox for studying cryptic structure of sex chromosomes.

genomics↗

Protection from liver cancer in a mouse model of Alagille syndrome follows dysregulated differentiation of thymocytes and hepatocytes

Fibrosis is a physiological tissue repair mechanism, but excessive fibrosis can disrupt organ function. Alagille syndrome (ALGS), which is caused by mutations in the Notch ligand JAGGED1, results in bile duct paucity, neonatal cholestasis, and a characteristic fibrotic response. Here, we show that Jag1Ndr/Ndr mice, a model for ALGS, recapitulates ALGS-like pericellular fibrosis. Single-cell RNA-seq and multi-color flow cytometry characterization of the liver and spleen revealed immature hepatocytes and paradoxically low intrahepatic T cell infiltration in cholestatic Jag1Ndr/Ndr mice, despite an enrichment in extrahepatic (thymic and splenic) regulatory T cells (Tregs). Jag1Ndr/Ndr lymphocyte immune and fibrotic capacity was tested with adoptive immune cell transplantation into Rag1-/- mice, challenged with dextran sulfate sodium (DSS) or bile duct ligation (BDL). Transplanted Jag1Ndr/Ndr lymphocytes were less inflammatory with fewer activated T cells than Jag1+/+ lymphocytes, in response to DSS. Cholestasis induced by BDL in Rag1-/- mice with Jag1Ndr/Ndr lymphocytes resulted in periportal Treg accumulation and three-fold less periportal fibrosis than in Rag1-/- mice with Jag1+/+ lymphocytes. Finally, we show that the Jag1Ndr/Ndr hepatocyte expression profile and Treg overrepresentation are corroborated by transcriptomic data from children with ALGS. In sum, these data lead to a model in which Jag1-driven developmental hepatic and immune defects interact to determine the fibrotic process in ALGS.

developmental biology↗

A high-quality de novo genome assembly based on nanopore sequencing of a wild-caught coconut rhinoceros beetle (Oryctes rhinoceros)

BackgroundAn optimal starting point for relating genome function to organismal biology is a high-quality nuclear genome assembly, and long-read sequencing is revolutionizing the production of this genomic resource in insects. Despite this, nuclear genome assemblies have been under-represented for agricultural insect pests, particularly from the order Coleoptera. Here we present a de novo genome assembly and structural annotation for the coconut rhinoceros beetle, Oryctes rhinoceros (Coleoptera: Scarabaeidae), based on Oxford Nanopore Technologies (ONT) long-read data generated from a wild-caught female, as well as the assembly process that also led to the recovery of the complete circular genome assemblies of the beetles mitochondrial genome and that of the biocontrol agent, Oryctes rhinoceros nudivirus (OrNV). As an invasive pest of palm trees, O. rhinoceros is undergoing an expansion in its range across the Pacific Islands, requiring new approaches to management that may include strategies facilitated by genome assembly and annotation. ResultsHigh-quality DNA isolated from an adult female was used to create four ONT libraries that were sequenced using four MinION flow cells, producing a total of 27.2 Gb of high-quality long-read sequences. We employed an iterative assembly process and polishing with one lane of high-accuracy Illumina reads, obtaining a final size of the assembly of 377.36 Mb that had high contiguity (fragment N50 length = 12 Mb) and accuracy, as evidenced by the exceptionally high completeness of the benchmarked set of conserved single-copy orthologous genes (BUSCO completeness = 99.11%). These quality metrics place our assembly as the most complete of the published Coleopteran genomes. The structural annotation of the nuclear genome assembly contained a highly-accurate set of 16,371 protein-coding genes showing BUSCO completeness of 92.09%, as well as the expected number of non-coding RNAs and the number and structure of paralogous genes in a gene family like Sigma GST. ConclusionsThe genomic resources produced in this study form a foundation for further functional genetic research and management programs that may inform the control and surveillance of O. rhinoceros populations, and we demonstrate the efficacy of de novo genome assembly using long-read ONT data from a single field-caught insect.

genomics↗

Eliminating Aedes aegypti from its southern margin in Australia: insights from genomic data and simulation modeling

A rare example of a successful long-term elimination of the mosquito Aedes aegypti is in Brisbane, Queensland, where the legislatively-enforced removal of rainwater tanks drove its disappearance by the mid-1950s. However, a decade-long drought led to the mass installation of rainwater tanks throughout the region, re-introducing critical breeding sites for the mosquitos persistence in this subtropical region. With Ae. aegypti re-invading towns just 150 km north of Brisbane, we examined the potential for their sustained elimination. Through genomic analyses, we estimated historical expansion and current isolation between neighboring populations as close as 15 kilometers. The estimated recent migration rate, entomological and meteorological data were used to calibrate the simulations of elimination campaigns in the two southernmost populations. Our simulations indicate that Ae. aegypti could be eliminated with moderate release numbers of incompatible Wolbachia-infected (IIT) males (sorted with an error rate [≤]10-6) if non-compliant rainwater tanks are removed first. With this combined campaign, highly effective suppression (>99%) was predicted in both towns, and complete elimination was predicted in 35% of simulations in one town. Without tank removal, however, IIT led to a moderate suppression (61-93%) even with a 40:1 ratio of released IIT males to local males. Moreover, with a ratio of >20:1, Wolbachia establishment was predicted when the sorting error was >10-7. Our conservative estimates of intervention outcomes inform the planning of Ae. aegypti elimination in the region, and offer insight into the effective combinations of conventional and novel control tools, particularly for vulnerable mosquito populations at range margins. SignificanceAfter decades of range stagnation in Australia, the Aedes aegypti mosquito is expanding southward, approaching the most-densely-populated areas of Queensland. Using population genomics and simulation modeling of elimination campaigns, we show that Australias southernmost populations of this disease vector are genetically isolated and could be eliminated with moderate releases of incompatible Wolbachia-infected males if major larval breeding sites (non-compliant rainwater tanks) are removed first. The risk of Wolbachia establishment for this approach is low, and so is the risk of quick mosquito re-invasion. Our conservative estimates of intervention outcomes inform the planning of Ae. aegypti elimination in the region, and offer new insight into the benefits of combining conventional and novel control tools, particularly for mosquito populations at range margins.

systems biology↗

The complete mitochondrial genome sequence of Oryctes rhinoceros (Coleoptera: Scarabaeidae) based on long-read nanopore sequencing

The coconut rhinoceros beetle (CRB, Oryctes rhinoceros) is a severe and invasive pest of coconut and other palms throughout Asia and the Pacific. The biocontrol agent, Oryctes rhinoceros nudivirus (OrNV), has successfully suppressed O. rhinoceros populations for decades but new CRB invasions started appearing after 2007. A single-SNP variant within the mitochondrial cox1 gene is used to distinguish the recently-invading CRB-G lineage from other haplotypes, but the lack of mitogenome sequence for this species hinders further development of a molecular toolset for biosecurity and management programmes against CRB. Here we report the complete circular sequence and annotation for CRB mitogenome, generated to support such efforts. Sequencing data were generated using long-read Nanopore technology from genomic DNA isolated from a CRB-G female. The mitochondrial genome was assembled with Flye v.2.5, using the short-read Illumina sequences to remove homopolymers with Pilon, and annotated with MITOS. Independently-generated transcriptome data were used to assess the O. rhinoceros mitogenome annotation and transcription. The aligned sequences of 13 protein-coding genes (PCGs) (with degenerate third codon position) from O. rhinoceros, 13 other Scarabaeidae taxa and two outgroup taxa were used for the phylogenetic reconstruction with the Maximum likelihood (ML) approach in IQ-TREE and Bayesian (BI) approach in MrBayes. The complete circular mitochondrial genome of O. rhinoceros is 20,898 bp-long, with a gene content canonical for insects (13 PCGs, 2 rRNA genes, and 22 tRNA genes), as well as one structural variation (rearrangement of trnQ and trnI) and a long control region (6,204 bp). Transcription was detected across all 37 genes, and interestingly, within three domains in the control region. ML and BI phylogenies had the same topology, correctly grouping O. rhinoceros with one other Dynastinae taxon, and recovering the previously reported relationship among lineages in the Scarabaeidae. In silico PCR-RFLP analysis recovered the correct fragment set that is diagnostic for the CRB-G haplogroup. These results validate the high-quality of the CRB mitogenome sequence and annotation.

genomics↗

Using spatial genetics to quantify mosquito dispersal for control programs

BackgroundHundreds of millions of people get a mosquito-borne disease every year, of which nearly one million die. Mosquito-borne diseases are primarily controlled and mitigated through the control of mosquito vectors. Accurately quantified mosquito dispersal in a given landscape is critical for the design and optimization of the control programs, yet the field experiments that measure dispersal of mosquitoes recaptured at certain distances from the release point (mark-release-recapture MRR studies) are challenging for such small insects and often unrepresentative of the insects true field behavior. Using Singapore as a study site, we show how mosquito dispersal patterns can be characterized from the spatial analyses of genetic relatedness among individuals sampled over a short time span without interruption of their natural behaviors. Methods and FindingsWe captured ovipositing females of Aedes aegypti, a major arboviral disease vector, across floors of high-rise apartment blocks and genotyped them using thousands of genome-wide SNP markers. We developed a methodology that produces a dispersal kernel for distance that results from one generation of successful breeding (effective dispersal), using the distances separating full siblings, 2nd and 3rd degree relatives (close kin). In Singapore, the estimated dispersal distance kernel was exponential (Laplacian), giving the mean effective dispersal distance (and dispersal kernel spread {sigma}) of 45.2 m (95%CI: 39.7-51.3 m), and 10% probability of dispersal >100 m (95%CI: 92-117 m). Our genetic-based estimates matched the parametrized dispersal kernels from the previously reported MRR experiments. If few close-kin are captured, a conventional genetic isolation-by-distance analysis can be used, and we show that it can produce {sigma} estimates congruent with the close-kin method, conditioned on the accurate estimation of effective population density. We also show that genetic patch size, estimated with the spatial autocorrelation analysis, reflects the spatial extent of the dispersal kernel tail that influences e.g. predictions of critical radii of release zones and Wolbachia wave speed in mosquito replacement programs. ConclusionsWe demonstrate that spatial genetics (the newly developed close-kin analysis, and conventional IBD and spatial autocorrelation analyses) can provide a detailed and robust characterization of mosquito dispersal that can guide operational vector control decisions. With the decreasing cost of next generation sequencing, acquisition of spatial genetic data will become increasingly accessible, and given the complexities and criticisms of conventional MRR methods, but the central role of dispersal measures in vector control programs, we recommend genetic-based dispersal characterization as the more desirable means of parameterization.

ecology↗

Complete genome sequence of Oryctes rhinoceros Nudivirus isolated from Coconut Rhinoceros Beetle in the Solomon Islands

Oryctes Nudivirus (OrNV) has been an effective biocontrol agent against the insect pest Oryctes rhinoceros (Coleoptera: Scarabaeidae) for decades, but there is evidence that resistance could be evolving in some host populations. We detected OrNv infection in O. rhinoceros from the Solomon Islands and used Oxford Nanopore Technologies (ONT) long-read sequencing to determine the full length of the virus genomic sequence isolated from an individual belonging to a mitochondrial lineage (CRB-G) that was previously reported as resistant to OrNV. The complete circular genome of the virus consisted of 125,917 nucleotides, encoding 130 open reading frames (ORFs) for proteins in the range ~5 kDa (51aa) to ~140 kDa (1280aa). This Solomon Islands isolate has high (99.85%) nucleotide sequence identity to the previously sequenced isolate PV505 from Southern Luzon, Philippines, and has 138 amino acid modifications when compared with the originally described full genome sequence of the Ma07 strain from Malaysia.

genomics↗

Molecular definition of group 1 innate lymphoid cells in the mouse uterus

Determining the function of uterine lymphocytes is challenging because of the rapidly changing nature of the organ in response to sex hormones and, during pregnancy, to the invading fetal trophoblast cells. Here we provide the first genome-wide transcriptome atlas of mouse uterine group 1 innate lymphoid cells (g1 ILCs) at mid-gestation. The composition of g1 ILCs fluctuates throughout reproductive life, with Eomes-veCD49a+ ILC1s dominating before puberty and specifically expanding in second pregnancies, when the expression of CXCR6, a marker of memory cells, is upregulated. Tissue-resident Eomes+CD49a+ NK cells (trNK), which resemble human uterine NK cells, are most abundant during early pregnancy, and showcase gene signatures of responsiveness to TGF-{beta}, connections with trophoblast, epithelial, endothelial and smooth muscle cells, leucocytes, as well as extracellular matrix. Unexpectedly, trNK cells express genes involved in anaerobic glycolysis, lipid metabolism, iron transport, protein ubiquitination, and recognition of microbial molecular patterns. Conventional NK cells expand late in gestation and may engage in crosstalk with trNK cells involving IL-18 and IFN-{gamma}. These results identify trNK cells as the cellular hub of uterine g1 ILCs at mid-gestation and mark CXCR6+ ILC1s as potential memory cells of pregnancy.

immunology↗

Improved Aedes aegypti mosquito reference genome assembly enables biological discovery and vector control

Female Aedes aegypti mosquitoes infect hundreds of millions of people each year with dangerous viral pathogens including dengue, yellow fever, Zika, and chikungunya. Progress in understanding the biology of this insect, and developing tools to fight it, has been slowed by the lack of a high-quality genome assembly. Here we combine diverse genome technologies to produce AaegL5, a dramatically improved and annotated assembly, and demonstrate how it accelerates mosquito science and control. We anchored the physical and cytogenetic maps, resolved the size and composition of the elusive sex-determining \"M locus\", significantly increased the known members of the glutathione-S-transferase genes important for insecticide resistance, and doubled the number of chemosensory ionotropic receptors that guide mosquitoes to human hosts and egg-laying sites. Using high-resolution QTL and population genomic analyses, we mapped new candidates for dengue vector competence and insecticide resistance. We predict that AaegL5 will catalyse new biological insights and intervention strategies to fight this deadly arboviral vector.

genomics↗

Fine-scale landscape genomics of Aedes aegypti reveals loss of Wolbachia transinfection, dispersal barrier and potential for occasional long distance movement

The endosymbiotic bacterium Wolbachia suppresses the capacity for arboviral transmission in the mosquito Aedes aegypti, and can spread through wild mosquito populations following local introductions. Recent introductions in Cairns, Australia have demonstrated slower than expected spread, that could be due to: i) barriers to Ae. aegypti dispersal; ii) leptokurtically distributed dispersal distances; and iii) intergenerational loss of Wolbachia. We investigated these three potential causes using genome-wide single-nucleotide polymorphisms (SNPs) and an assay for the Wolbachia infection wMel in 161 Ae. aegypti collected from Cairns in 2015. We observed a significant barrier effect of Cairns highways on Ae. aegypti dispersal using distance-based redundancy analysis and patch-based simulation analysis. We detected putative full-siblings in ovitraps 1312m apart, suggesting long-distance female movement likely mediated by human transport. Finally, we found a pair of full-siblings of different infection status, suggesting loss of Wolbachia in the field. While the long-distance movement and Wolbachia loss currently represent single observations, these findings together with the identified dispersal barriers can contribute to the slow spread of Wolbachia through the Ae. aegypti population in Cairns. Our landscape genomics approach can be extended to other host/symbiont systems that are being considered for biocontrol.

ecology↗