Biology subjects

Singh, V. K.

Publications and source records attributed to Singh, V. K..

At least 19 recordsLinked to original sources

bioRxiv2026

Enhancement of low-temperature growth of Staphylococcus aureus by low concentrations of antimicrobial unsaturated fatty acids

The incorporation of oleic acid, a physiologically relevant and relatively non-toxic fatty acid, into membrane phospholipids and glycolipids has major impacts on the membrane biophysical properties of Staphylococcus aureus, including the promotion of low-temperature growth. Inclusion of oleic acid in growth media decreased the minimum growth temperature of S. aureus. It has not been studied yet whether other physiologically relevant, yet more antimicrobial straight-chain unsaturated fatty acids (SCUFAs), elicit similar responses. Here, we report that exogenous addition of these antimicrobial SCUFAs at 12{degrees}C led to their incorporation into the membrane lipids in only relatively small amounts, which, however, was sufficient to strongly promote growth at low temperatures. Intriguingly, these SCUFAs showed a preferential incorporation into diglucosyldiacylglyceride (DGDG) over phosphatidyl glycerol, and increased DGDG levels [~] 4-fold in SCUFA-grown S. aureus. Two glycolipid-deficient mutants lost the growth-enhancing effects of SCUFAs at low temperatures and showed increased susceptibility to SCUFAs at 37{degrees}C, suggesting that glycolipids are important membrane components and are required for low-temperature adaptation. The presence of SCUFAs at low temperatures also enhanced the production of the carotenoid staphyloxanthin. Overall, our results suggest that multiple strategies are at play in the membrane lipid remodeling of S. aureus to adapt to the stress of low-temperature growth and likely to other environmental stresses. Incorporation of antimicrobial SCUFAs into membrane lipids may facilitate the insertion of free forms of these SCUFAs into the membrane and be a part of their mode of action.

microbiology↗

bioRxiv2026

Genetic diversity of Lactobacillus delbrueckii in home-made Dahi from different regions of India as revealed by genotyping-by-sequencing

Microbial diversity of bacterial species in home-made curd from different states of India was analyzed using genotyping-by-sequencing. The most prevalent species were Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus helveticus, Streptococcus thermophilus and Lactobacillus kefiranofaciens. Pathogenic species such as Salmonella enterica serovar Typhimurium and Shigella dysenteriae were found in over 60% of samples. High intraspecific variation was observed in Acinetobacter baumannii, Bacillus cereus, Enterococcus faecium, Escherichia coli, Lactococcus lactis subsp. cremoris, Lactococcus piscium, Salmonella enterica serovar Typhimurium and Shigella dysenteriae. Intra-specific genetic relatedness in Lactobacillus delbrueckii subsp. bulgaricus in curd samples largely correlated with their respective sites of collection. Research HighlightsO_LIMetagenomic DNA from home-made Dahi (curd) samples from various states in India were used for GBS-SNPs C_LIO_LIGBS-SNPs were able to resolve within-species variability across the samples. C_LIO_LIMajority of the samples contained both probiotic as well as potential pathogenic bacteria. C_LIO_LISeveral of curd samples contained multiple strains. C_LI

microbiology↗

bioRxiv2025

Mapping the miRNA Landscape of Gallbladder Cancer: Genome-Wide Insights and Functional Implications

Gallbladder cancer (GBC), the sixth most aggressive gastrointestinal cancer, exhibits complex molecular dysregulation involving microRNAs (miRNAs) that drive tumor progression. This study has comprehensively profiled genome-wide miRNA expression in GBC cells revealing 971 known miRNAs, and 27 novel miRNAs. We identified 388 significantly differentially expressed (DE) miRNAs (191 upregulated and 197 downregulated), providing valuable insights into the various complex molecular mechanisms underlying GBC pathogenesis. These DE miRNAs target key biological processes, including hormone-induced signaling pathways, cell adhesion molecules, apoptosis, ferroptosis, and cancer-associated pathways, particularly those linked to gastric cancer. Profiling of DE miRNAs in GBC cells presents opportunities for novel miRNA-based diagnostic and prognostic approaches in GBC. Notably, among the DE miRNAs, the miR-17[~]92 cluster was significantly suppressed in GBC cells. We also show that miR-17[~]92 cluster targets and destabilizes an S-phase licensing factor Cdt2 (an oncogene) in GBC cells. miR-17[~]92 mediated negative regulation of Cdt2 induces S-phase arrest, leading to checked proliferation and invasive capabilities of GBC cells specifically, without any significant effect on non-cancerous cells, presenting miR-17[~]92 as a potential miRNA therapeutic for GBC. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=191 SRC="FIGDIR/small/679165v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@243970org.highwire.dtl.DTLVardef@36f578org.highwire.dtl.DTLVardef@2dba37org.highwire.dtl.DTLVardef@1c9e1b_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract C_FIG

cancer biology↗

bioRxiv2025

High-Throughput Screening and Initial SAR Studies Identify a Novel Sub-micromolar Potent Human cGAS Inhibitor

Cyclic GMP-AMP synthase (cGAS) has emerged as a promising therapeutic target of several human diseases, including Alzheimers disease (AD) and other neurodegenerative disorders. As a cytosolic DNA sensor, cGAS generates an innate immune response to promote neuroinflammation by producing an endogenous agonist of the stimulator of interferon genes (STING), 23-cyclic GMP-AMP (cGAMP), which activates the cGAS-STING pathway. We have performed a high-throughput screening of a chemical library containing over 300K small molecules at the Fisher Drug Discovery Resource Center (DDRC), Rockefeller University (RU), to identify multiple hit inhibitors of human (h)-cGAS. We used a modified Kinase Glo(R) Luminescent Kinase assay, which was earlier developed at RU and later used by multiple groups, including ours, to perform primary screening of the library using h-cGAS. The hit candidates bearing novel scaffolds are structurally diverse and exhibited in vitro activity in the low micromolar range. RU-0610270 or compound (cpd) 1, a sulfonamide derivative, is one of the most potent hits (IC50=1.88 {micro}M), selected for hit expansion and structure-activity relationship (SAR) analysis. We synthesized new analogs of cpd 1 and evaluated them in vitro against h-cGAS to identify cpd 6 (IC50=0.66 {micro}M) as the most potent hit analog. We further profiled cpd 6 and found that it modestly inhibited cGAMP levels by 29% at 30 {micro}M in THP1 cells without detectable toxicity, and by 76% at 100 {micro}M, albeit with a moderate decrease ([~]20%) in cell viability. These results highlight a novel chemical series with promising in vitro activity, providing a starting point for the development of selective and potent human cGAS inhibitors for clinical use.

neuroscience↗

bioRxiv2024

Sirtuin2 blockade inhibits replication of Human Immunodeficiency Virus-1 and 1 Mycobacterium tuberculosis in macrophages and humanized mice

Coinfections with Mycobacterium tuberculosis (Mtb) and HIV-1 present a critical health challenge and require treatment for survival. We found that human M1 macrophages inhibit Mtb growth, while M2 macrophages, characterized by elevated Sirt2 expression, permit Mtb growth. Further, we found that HIV-1 augmented Sirt2 gene expression in M[FE]s. Therefore, we explored the therapeutic potential of sirtuin-modulating drugs in M[FE]s. Sirtinol, a Sirt2 inhibitor, significantly reduced HIV-1 growth in M0, M1, and M2-M[FE]s by >1 log10 over 7 days. Conversely, individual doses of resveratrol and SRT1460, which activate Sirt1, did not affect HIV-1. However, their combination showed a strong synergistic inhibition of HIV-1. The combination of sirtinol with resveratrol was neither synergistic nor antagonistic. Sirtinol upregulated iNOS and ATG5 mRNA in HIV-1 infected M[FE]s in a phenotype-dependent manner. In a humanized mouse model (Hu-NSG-SGM3) co-infected with Mtb H37Rv and the HIV-1 BAL strain, treatment with sirtinol alone, or in combination with combination antiretroviral therapy (cART), showed promising results; Sirtinol alone reduced Mtb growth, while its combination with cART effectively inhibited HIV-1 replication in the organs. We propose that Sirt2 blockade and Sirt1-activation represent a novel dual therapeutic strategy for treating HIV-1 and Mtb coinfections.

immunology↗

bioRxiv2024

Skeletal Muscle Mitochondrial Dysfunction Mediated by Pseudomonas aeruginosa Quorum Sensing Transcription Factor MvfR: Reversing Effects with Anti-MvfR and Mitochondrial-Targeted Compounds

Sepsis and chronic infections with Pseudomonas aeruginosa, a leading "ESKAPE" bacterial pathogen, are associated with increased morbidity and mortality and skeletal muscle atrophy. The actions of this pathogen on skeletal muscle remain poorly understood. In skeletal muscle, mitochondria serve as a crucial energy source, which may be perturbed by infection. Here, using the well-established backburn and infection model of murine P. aeruginosa infection, we deciphered the systemic impact of the quorum sensing (QS) transcription factor MvfR by interrogating five days post-infection its effect on mitochondrial-related functions in the gastrocnemius skeletal muscle and the outcome of the pharmacological inhibition of MvfR function and that of the mitochondrial-targeted peptide, Szeto-Schiller 31 (SS-31). Our findings show that the MvfR perturbs ATP generation, oxidative phosphorylation (OXPHOS), and antioxidant response, elevates the production of reactive oxygen species, and promotes oxidative damage of mitochondrial DNA in the gastrocnemius muscle of infected mice. These impairments in mitochondrial-related functions were corroborated by the alteration of key mitochondrial proteins involved in electron transport, mitochondrial biogenesis, dynamics and quality control, and mitochondrial uncoupling. Pharmacological inhibition of MvfR using the potent anti-MvfR lead, D88, we developed, or the mitochondrial-targeted peptide SS-31 rescued the MvfR- mediated alterations observed in mice infected with the wild-type strain PA14. Our study provides insights into the actions of MvfR in orchestrating mitochondrial dysfunction in the skeletal murine muscle, and it presents novel therapeutic approaches for optimizing clinical outcomes in affected patients.

microbiology↗

bioRxiv2024

Lipidomics of homeoviscous adaptation to low temperatures in Staphylococcus aureus utilizing exogenous straight-chain unsaturated fatty acids over biosynthesized endogenous branched-chain fatty acids

It is well established that Staphylococcus aureus can incorporate exogenous straight-chain unsaturated fatty acids (SCUFAs) into membrane phospho- and glyco-lipids from various sources in supplemented culture media, and when growing in vivo in an infection. Given the enhancement of membrane fluidity when oleic acid (C18:1{Delta}9) is incorporated into lipids, we were prompted to examine the effect of medium supplementation with C18:1{Delta}9 on growth at low temperatures. C18:1{Delta}9 supported the growth of a cold-sensitive, branched-chain fatty acid (BCFA)-deficient mutant at 12{degrees}C. Interestingly, we found similar results in the BCFA-sufficient parental strain. We show that incorporation of C18:1{Delta}9 and its elongation product C20:1{Delta}9 into membrane lipids was required for growth stimulation and relied on a functional FakAB incorporation system. Lipidomics analysis of the phosphatidylglycerol (PG) and diglycosyldiacylglycerol (DGDG) lipid classes revealed major impacts of C18:1{Delta}9 and temperature on lipid species. Growth at 12{degrees}C in the presence of C18:1{Delta}9 also led to increased production of the carotenoid pigment staphyloxanthin; however, this was not an obligatory requirement for cold adaptation. Enhancement of growth by C18:1{Delta}9 is an example of homeoviscous adaptation to low temperatures utilizing an exogenous fatty acid. This may be significant in the growth of S. aureus at low temperatures in foods that commonly contain C18:1{Delta}9 and other SCUFAs in various forms. IMPORTANCEWe show that S. aureus can use its known ability to incorporate exogenous fatty acids to enhance its growth at low temperatures. Individual species of phosphatidylglycerols and diglycosyldiacylglycerol bearing one or two degrees of unsaturation derived from incorporation of C18:1{Delta}9 at 12{degrees}C are described for the first time. In addition, enhanced production of the carotenoid staphyloxanthin occurs at low temperatures. The studies describe a biochemical reality underlying in membrane biophysics. This is an example of homeoviscous adaptation to low temperatures utilizing exogenous fatty acids over the regulation of the biosynthesis of endogenous fatty acids. The studies have likely relevance to food safety in that unsaturated fatty acids may enhance growth of S. aureus in the food environment.

microbiology↗

bioRxiv2023

Signal Peptide of Human Serum Albumin (residues 1-18) Forms Amyloid-like Aggregates

Signal peptides (SPs) are essential tools in sorting or translocating the synthesized proteins. However, except few examples, their studies in isolation are quite limited. Here we asked a question of the aggregation propensity of signal peptide (residues 1-18) of Human Serum Albumin (HSA). Molecular dynamic simulations were used to acquire observations into the mechanism through which signal peptides of HSA self-aggregated in physiological conditions. Further, we confirmed our results by combining dye-based assays, atomic force microscopy, and transmission electron microscopy techniques. It was noted that the signal peptide of HSA (region 1-18) forms typical amyloid-like fibrils. Graphical O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=170 SRC="FIGDIR/small/563726v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@404ffaorg.highwire.dtl.DTLVardef@42e4caorg.highwire.dtl.DTLVardef@1ba942aorg.highwire.dtl.DTLVardef@556bee_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

bioRxiv2023

DeepMap: A deep learning-based model with four-line code for prediction-based breeding in crops

Prediction of phenotype through genotyping data using the emerging machine or deep learning technology has been proven successful in genomic prediction. We present here a graphical processing unit (GPU) enabled DeepMap configurable deep learning-based python package for the genomic prediction of quantitative phenotype traits. We found that deep learning captures non-linear patterns more efficiently than conventional statistical methods. Furthermore, we suggest an additional module inclusion of epistasis interactions and training of the model on Graphical Processing Units (GPUs) in addition to Central Processing Unit (CPU) to enhance efficiency and increase the models performance. We developed and demonstrated the application of DeepMap using a 3K rice genome panel and 1K-Rice Custom Amplicon (1kRiCA) data for several phenotypic traits including days to 50% flowering (DTF), number of productive tillers (NPT), panicle length (PL), plant height (PH), and plot yield (PY). We have found that DeepMap outperformed the best existing state-of-the-art models by giving higher predictive correlation and low mean squared error for the datasets studied. This prediction performance was higher than other compared models in the range of 13-31%. Similarly for Dataset-2, significantly higher predictions were observed than the compared models (16-20% higher prediction ability). On Dataset-3, we have also shown the better and versatile performance of our model across crops (wheat, maize, and soybean) for yield and yield-related traits. This demonstrates the potentiality of the framework and ease of use for future research in crop improvement. The DeepMap is accessible at https://test.pypi.org/project/DeepMap-1.0/. Short SummaryDeepMap is a deep learning-based breeder-friendly python package to perform genomic prediction. It utilizes epistatic interactions for data augmentation and outperforms the existing state-of-the-art machine/deep learning models such as Bayesian LASSO, GBLUP, DeepGS, and dualCNN. DeepMap developed for rice and tested across crops such as maize, wheat, soybean etc.

genomics↗

bioRxiv2023

Genetic Gains in IRRIs Rice Salinity Breeding and Elite Panel Development as a Future Breeding Resource

Genetic gain is a crucial parameter to check the breeding programs success and help optimize future breeding strategies for enhanced genetic gains. In this work, IRRIs historical data from the Philippines and Bangladesh of the salinity breeding program was used to estimate the genetic gains and identify the best lines based on higher breeding values for yield as a future genetic resource. Two-stage mixed-model approach accounting for experimental design factors and pedigrees was adopted to obtain the breeding values for yield and estimate genetic trends under the salinity conditions. A positive genetic trend of 0.1% per annum with a yield advantage of 1.52 kg/ha for the Philippines and 0.31% per annum with a yield advantage of 14.02 kg/ha for Bangladesh datasets was observed. For the released varieties, genetic gain was 0.12% per annum with a yield advantage of 2.2 kg/ha/year and 0.14% per annum with a yield advantage of 5.9 kg/ha/year, respectively. Further, based on higher breeding values for grain yield, a core set of the top 145 genotypes with higher breeding values of >2400 kg/ha in the Philippines and >3500 kg/ha in Bangladesh with a selection accuracy >0.4 were selected for formulating the elite breeding panel as a future breeding resource. Conclusively, higher genetic gains are pivotal in IRRIs rice salinity breeding program, which requires a holistic breeding approach with a major paradigm shift in breeding strategies to enhance genetic gains. Key MessageEstimating genetic gains and formulating a future salinity elite breeding panel for rice pave the way for developing better high-yielding salinity tolerant lines with enhanced genetic gains.

genetics↗

bioRxiv2023

From gonadogenesis to testicular cancer: Unravelling the novel regulators and identification of drug candidates against FGF9 and PTGDS

Sex determination is the preliminary step toward gonadogenesis in mammals. Antagonistic interactions of key regulators have been only fragmentarily mentioned so far. Therefore, exploring regulators underlying the phenomena is required to solve questions, especially regarding female gonad development and gonadal disorders in congenital or adults. Inhibiting discrepancies in PPI pathways and combating related disorders are of urgent necessity, for which novel drugs are constantly required. Here, we performed in silico analysis using robust bioinformatics methods, which is unprecedented work in sex determination studies, providing large-scale analysis without exorbitant wet lab procedures. Analyzed regulators were overlapped with our RNA-seq data for authentication, to obtain differentially expressed elements. Additionally, CADD approach was used to discover inhibitors for FGF9 and PTGDS to search for potential drugs combating gonadal disorders in adults. Along with druggable properties, only FGF9 and PTGDS had full-length protein structures available, among 25 key genes under investigation. Our large-scale analysis of PPIN, produced highly interacting hub-bottleneck nodes as novel genes. Further, functional enrichment analysis revealed importance of these regulators in gonadogenesis. We identified sex-specific novel genes, miRNAs-target pairs, and lncRNAs-target pairs, which appear to play an important role in regulation of ovary development. CADD with molecular docking, MD simulations, and molecular mechanics confirmed stability of two novel compounds, DB12884 and DB12412 that could potentially inhibit FGF9 and PTGDS respectively. Taken together our study provides valuable information regarding involvement of crucial regulators in antagonistic mechanism of gonadogenesis and their related disorders, which will further assist in refining wet lab experiments.

bioinformatics↗

bioRxiv2023

Increased membrane fluidity and cell wall thickening contribute to high-level daptomycin resistance in S. aureus with defective pgsA and yycG

Daptomycin is a membrane-targeting last-resort antimicrobial therapeutic for the treatment of infections caused by methicillin- and/or vancomycin-resistant Staphylococcus aureus. In the rare event of failed daptomycin therapy, the source of resistance is often attributable to mutations directly within the membrane phospholipid biosynthetic pathway of S. aureus or in the regulatory systems that control cell envelope response and membrane homeostasis. Here we describe the structural changes to the cell envelope in a daptomycin-resistant isolate of S. aureus strain N315 that has acquired mutations in the genes most commonly reported associated with daptomycin-resistance: mprF, yycG, and pgsA. In addition to the decreased phosphatidylglycerol (PG) levels that are the hallmark of daptomycin-resistance, the mutant with high-level daptomycin resistance had increased branched-chain fatty acids (BCFAs) in its membrane lipids, increased membrane fluidity, and increased cell wall thickness. However, the successful utilization of isotope-labeled straight-chain fatty acids (SCFAs) in lipid synthesis suggested that the aberrant BCFA:SCFA ratio arose from upstream alteration in fatty acid synthesis rather than a structural preference in PgsA. RT-qPCR studies revealed that expression of pyruvate dehydrogenase (pdhB) was suppressed in the daptomycin-resistant isolate, which is known to increase BCFA levels. While complementation with an additional copy of pdhB had no effect, complementation of the pgsA mutation resulted in increased PG formation, reduction in cell wall thickness, restoration of normal BCFA levels, and increased daptomycin susceptibility. Collectively, these results demonstrate that pgsA contributes to daptomycin resistance through its influence on membrane fluidity and cell wall thickness, in addition to phosphatidylglycerol levels. IMPORTANCEThe cationic lipopeptide antimicrobial daptomycin has become an essential tool for combating infections with Staphylococcus aureus that display reduced susceptibility to {beta}-lactams or vancomycin. Since daptomycins activity is based on interaction with the negatively charged membrane of S. aureus, routes to daptomycin-resistance occur through mutations in the lipid biosynthetic pathway surrounding phosphatidylglycerols and the regulatory systems that control cell envelope homeostasis. Therefore, there are many avenues to achieve daptomycin resistance and several different, and sometimes contradictory, phenotypes of daptomycin-resistant S. aureus, including both increased and decreased cell wall thickness and membrane fluidity. This study is significant because it demonstrates the unexpected influence of a lipid biosynthesis gene, pgsA, on membrane fluidity and cell wall thickness in S. aureus with high-level daptomycin resistance.

microbiology↗

bioRxiv2023

Inhibition of miR-214 expression by small molecules alleviates head and neck cancer metastasis by targeting ALCAM/TFAP2 signaling.

Predominantly, head and neck cancer (HNC) is considered a regional disease and develops in the nasal cavity, oral cavity, tongue, pharynx, and larynx. In the advanced stage, the HNC spread into distant organs. By the time head and neck cancer diagnosed, the estimated metastasis is occurred in 10-40% cases. The most important vital organs affected by distant metastasis are the lungs, bones, and liver. Despite several advancements in chemotherapies, no significant changes are observed as 5-year survival rate remains the same. Therefore, it is crucial to decipher molecular mechanisms contributing to the metastatic dissemination of head and neck cancer. Here, we tested a novel ALCAM/TFAP2 signaling by targeting multidisciplinary miR-214 expression in head and cancer cells. Our results revealed that HNC cell lines (CAL27, SCC-9, SCC-4, and SCC-25) exhibit higher expression of miR-214 compared with normal human bronchial epithelial (NHBE) cells. Higher expression of miR-214 drives the invasive potential of these cell lines. Down-regulation of miR-214 in CAL27 and SCC-9 cells either using an anti-miR-214 inhibitor (50nM) or a small molecule of green tea (EGCG) inhibited cell invasion. Treating CAL27 and SCC-9 cells with EGCG also reduces ALCAM expression, a key activated leukocyte cell adhesion molecule, potentially blocking mesenchymal phenotype. Dietary administration of EGCG significantly inhibits distant metastasis of SCC-9 cells into the lungs, liver, and kidneys. Our results also demonstrate that the reduction of miR-214 expression influences in vitro cell movement and extravasation, as evident by reduced CD31 expression, a neovascularization marker. Together, these studies suggest that identifying bioactive molecules that can inhibit distant metastasis regulated by the miRNAs may provide potent interventional approaches and a better understanding of the complex functions of miRNAs and their therapeutic targets for clinical application.

cancer biology↗

bioRxiv2023

Differentially deregulated microRNAs contribute to ultraviolet radiation-induced photocarcinogenesis through immunomodulation: An-analysis of microRNAs expression profiling.

MicroRNAs (miRNAs) are short non-coding RNA molecules (18-25 nucleotides) that regulate several fundamental biological processes. Emerging evidence has shown more than 1500 miRNAs functions in the cell cycle, proliferation, apoptosis, oxidative stress, immune response, DNA damage, and epigenetics alterations. miRNAs are bidirectionally in nature and act as a tumor suppressor and as an oncogene through crosstalk between tumor cells and immune cells. Although the roles of miRNAs in several cancers are well studied, little is known about ultraviolet B (UVB) radiation-induced skin cancer. Here, we performed a comprehensive screening of 1281 miRNAs in tumor tissues and compared their expression with normal skin. Our results demonstrate that the expression levels of 587 miRNAs were altered in tumor tissues compared to their expression in normal skin. The expression of 337 miRNAs was upregulated from 1.5-12 folds, while the expression of 250 miRNAs was downregulated up to 1.5-10 folds in tumors. Further, intraperitoneal injection of a mimic of down-regulated miR-15b (30nM) and an inhibitor of upregulated miR-133a (20nM) protect UVB-induced suppression of contact hypersensitivity (CHS) response. In conclusion, we identified a network of altered miRNAs in tumors that can serve as prognostic biomarkers and therapeutic targets to manage photocarcinogenesis effectively.

cancer biology↗

bioRxiv2021

Identification of multi-omics molecular signature of acute radiation injury using nonhuman primate model

The availability of validated biomarkers to assess radiation exposure and to assist in developing medical countermeasures remains an unmet need. We used a cobalt-60 gamma-irradiated nonhuman primate (NHP) model to delineate a multi-omics-based serum probability index of radiation exposure. Both male and female NHPs were irradiated with different doses ranging from 6.0 to 8.5 Gy, with 0.5 Gy increments between doses. We leveraged high resolution mass spectrometry for analysis of metabolites, lipids, and proteins at 1,2, and 6 days post-irradiation in NHP serum. A logistic regression model was implemented to develop a 4-analyte panel to stratify irradiated NHPs from unirradiated with high accuracy that was agnostic for all doses of {gamma}-rays tested in the study, up to six days after exposure. This panel was comprised of Serpin Family A9, acetylcarnitine, PC (16:0/22:6), and suberylglycine, which showed 2 - 4-fold elevation in serum abundance upon irradiation in NHPs, and can potentially be translated for human use following larger validation studies. Taken together, this study, for the first time, demonstrates the utility of a combinatorial molecular characterization approach using an NHP model for developing minimally invasive assays from small volumes of blood that can be effectively used for radiation exposure assessments.

biochemistry↗

bioRxiv2021

A multi-omics approach identifies pancreatic cancer cell extracellular vesicles as mediators of the unfolded protein response in normal pancreatic epithelial cells.

Although cancer-derived extracellular vesicles (cEVs) are thought to play a pivotal role in promoting cancer progression events, their precise effect on neighboring normal cells is unknown. In this study, we investigated the impact of pancreatic cancer ductal adenocarcinoma (PDAC) derived EVs on recipient non-tumorigenic pancreatic normal epithelial cells upon internalization. We show that PDAC cEVs increase the proliferation and invasive capability of treated normal cells. We further demonstrate that cEVs induce endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) in treated normal pancreatic epithelial cells within 24 hours. Subsequently, these cells release several inflammatory cytokines. Leveraging a layered multi-omics approach, we analyzed EV cargo from a panel of 6 PDAC and 2 normal pancreas cell lines, using multiple EV isolation methods. We found that cEVs were enriched for an array of biomolecules which can induce or regulate ER stress and the UPR, including palmitic acid, sphingomyelins, metabolic regulators of tRNA charging and proteins which regulate trafficking and degradation. We further show that palmitic acid, at doses relevant to those found in cEVs, is sufficient to induce ER stress in normal pancreas cells. These results suggest that cEV cargo packaging may be designed to disseminate proliferative and invasive characteristics upon internalization by distant recipient normal cells, hitherto unreported. This study is among the first to highlight a major role for PDAC cEVs to induce stress in treated normal pancreas cells that may modulate a systemic response leading to altered phenotypes. For the first time, our study implicates cEV transported palmitic acid as a potential driver in this process. These findings highlight the importance of EVs in mediating disease etiology and open potential areas of investigation toward understanding the role of cEV lipids in promoting cell transformation in the surrounding microenvironment.

cancer biology↗

bioRxiv2021

Immunometabolic hijacking of immune cells by a Pseudomonas aeruginosa quorum-sensing signal

Macrophages utilize metabolic pathways to generate energy and metabolites that may be vulnerable to pathogen hijacking to favor pathogen survival and persistence. It is unclear how bacterial pathogens alter metabolic pathways in immune cells for their benefit and persistence in the infected host. We have shown that the Pseudomonas aeruginosa quorum sensing (QS) signal molecule 2-aminoacetophenone (2-AA) allows pathogen persistence in host tissues by triggering host tolerization via histone deacetylase (HDAC)1-mediated epigenetic reprogramming. Here, we provide strong evidence that 2-AA-meditated persistence is linked to specific metabolic pathway alterations that reduce energy availability and biosynthetic macromolecules involved in host immune responses. 2-AA promotes a Warburg-like metabolic reprogramming effect, thereby increasing levels of lactate, which repressed inflammatory signaling in macrophages. Moreover, it interferes with pyruvate translocation to mitochondria, reducing mitochondrial (mt)-oxidative phosphorylation (OXPHOS) due to down-regulation of estrogen-regulated receptor (ERR) and mitochondrial pyruvate carrier (MPC)-1. This metabolic reprogramming dampened energy production, reduced the acetyl-CoA pool, and generated an anti-inflammatory milieu that favors P. aeruginosa persistence. These findings provide evidence of first-in-class metabolic reprogramming in immune cells mediated by a QS signaling molecule. The specific metabolic programs affected provide insights that may guide the design and development of therapeutics and protective interventions against pathogen-induced immunometabolic alterations and persistence factors.

microbiology↗

bioRxiv2020

New insights of zoogeographical distribution of Himalayan goral (Naemorhedus goral) from Indian Himalayan Region

In the present study, we explored the intraspecific genetic variation and phylogeographic relationship among all the reported species in the genus Naemorhedus distributed in a wide range of habitats. The Bayesian based phylogeny demonstrated that Himalayan goral, is a highly diverged species from the other reported species of gorals. We claim the presence of two valid sub-species of Himalayan goral, i.e. N. g. bedfordi and N. g. goral, distributed in the western and central Himalaya, respectively. The comparative analysis with the inclusion of data available from different ranges, suggests the presence of plausibly six species of gorals across the distribution with a few valid subspecies. Further, we report that N. griseus is a valid species and not the synonyms of N. goral considering the observed discrepancy in the available sequences. We recommend all the sub-species present at distant locations may be considered as Evolutionary Significant Units (ESUs) and, therefore, appeal to provide them special attention for long term conservation and management.

genetics↗