Biology subjects

Roy, R.

Publications and source records attributed to Roy, R..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

RAS pathway activation drives clonal selection and monocytic differentiation in FLT3 and BCL2 inhibitor resistance

Despite efficacy of FLT3 and BCL2 inhibition in acute myeloid leukemia (AML), relapse limits survival. Mutation status and AML monocytic differentiation are implicated in resistance. On-treatment tumor evolution may select for genetically distinct clones or shifts in differentiation not resolvable by bulk sequencing. We performed multiomic single cell (SC) DNA/protein and RNA/protein profiling of patients treated on a clinical trial of the BCL2 inhibitor venetoclax and the FLT3 inhibitor gilteritinib (Ven/Git) to characterize immunophenotypic, transcriptional, and genetic clonal evolution on therapy. We found that while Ven/Gilt effectively eliminated FLT3 mutant clones, it selected for RAS mutations, RAS pathway activation and RAS-associated monocytic differentiation. In an in vitro model of monocytic differentiation associated with heightened RAS pathway activation, we demonstrated that MEK inhibition re-sensitized to Ven/Gilt. These data indicate RAS signaling is central to FLT3 and BCL2 inhibitor resistance, is tightly coupled to monocytic differentiation and can be overcome by RAS pathway inhibition. COIC.C.S. has provided educational talks for Astellas Pharma, served on advisory boards for Genentech/Abbvie and received research funding from Abbvie. B.C., Y.S. and J.H. are employees of Abbvie. M.S. and H.H. are or were previously employees of Genentech. FundingThis work was supported in part by Abbvie. C.C.S. is a Leukemia & Lymphoma Society Scholar in Clinical Research and a Damon Runyon-Richard Lumsden Foundation Clinical Investigator supported (in part) by the Damon Runyon Cancer Research Foundation (CI-99-18). Statement of SignificanceMutational and non-mutational RAS signaling activation drives clonal selection, monocytic differentiation and treatment resistance to FLT3 and BCL2 inhibition in AML. MEK inhibition can resensitize resistant AML cells, suggesting therapeutic potential for combined FLT3, BCL2 and RAS pathway inhibition in AML.

cancer biology↗

bioRxiv2024

Characterization of DNA methylation in PBMCs and donor-matched iPSCs shows methylation is reset during stem cell reprogramming

O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=138 SRC="FIGDIR/small/627515v2_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@18cda69org.highwire.dtl.DTLVardef@574c4corg.highwire.dtl.DTLVardef@1522644org.highwire.dtl.DTLVardef@4e799c_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO C_FIG HighlightsO_LIGeneration of a population-level set of iPSC lines from healthy individuals across the lifespan C_LIO_LIAging-related features were reset based on epigenetic markers of cytosine methylation and telomere length C_LIO_LIBy comparing methQTLs in iPSC vs. their donor PBMCs, we find that detection of methQTLs reflect biological functions of different cell types C_LI DNA methylation is an important epigenetic mechanism that helps define and maintain cellular functions. It is influenced by many factors, including environmental exposures, genotype, cell type, sex, and aging. Since age is the primary risk factor for developing neurodegenerative diseases, it is important to determine if aging-related DNA methylation is retained when cells are reprogrammed to an induced Pluripotent Stem Cell (iPSC) state. Here, we selected peripheral blood mononuclear cells (PBMCs; n = 99) from a cohort of diverse and healthy individuals enrolled in the Genetic and Epigenetic Signatures of Translational Aging Laboratory Testing (GESTALT) study to convert to iPSCs. After reprogramming we evaluated the resulting iPSCs for DNA methylation signatures to determine if they reflect the confounding factors of age and environmental factors. We used genome-wide DNA methylation arrays in both cell types to show that the epigenetic clock is largely reset to an early methylation age after conversion of PBMCs to iPSCs. We further examined the epigenetic age of each cell type using an Epigenome-wide Association Study (EWAS). Finally, we identified a set of methylation Quantitative Trait Loci (methQTL) in each cell type. Our results show that age-related DNA methylation is largely reset in iPSCs, and each cell type has a unique set of methylation sites that are genetically influenced.

molecular biology↗

bioRxiv2024

Thermal Plasticity of Stage Specific Development Time in Drosophila melanogaster under Shifting Temperatures

We examined how thermal shifts influence development time and adult body size in Drosophila melanogaster. Individual flies were exposed to alternating temperatures of 25{degrees}C (optimal) and 17{degrees}C (cold), with shifts introduced at key developmental transitions: larval hatching and pupariation. We found while larval-stage temperature is the biggest determinant of thermal plasticity of development time and adult size, the egg-stage temperature also influences the pace of development and growth throughout pre-adult duration. The effect of low-to-high and high-to-low temperature shifts on development and growth may not be symmetric. When eggs are reared at 25{degrees}C and then shifted to 17{degrees}C, larval and pupal durations undergo reduction compared to constant 17{degrees}C, but it produces slightly larger adults. A higher egg-stage temperature thus seem to exert a carryover effect that accelerates subsequent development and growth when later stages experience colder temperatures. Surprisingly, flies whose egg stage is exposed to 17{degrees}C followed by a shift to 25{degrees}C also have reduced larval duration and larger size, relative to those developing at constant 25{degrees}C. We speculate this could be either because 17{degrees}C to 25{degrees}C represents a low-to-high temperature shift or a sub-optimal-to-optimal thermal shift that results in metabolic and/or hormonal changes accelerating differentiation and growth. While pupal duration is sensitive to current and to some extent prior thermal environments, it does not contribute substantially to thermal plasticity of size. Development time is longer in males than in females, and this difference seems to start from larval stage while the pupal duration plays a bigger role in creating this sex-specific difference. Overall, employing individual fly rearing, this study helped to unravel the effect of thermal shifts on growth and development in D. melanogaster with great precision.

evolutionary biology↗

bioRxiv2024

Cross-catalytic enhancement of peptides and RNA from a common prebiotic activated intermediate

Previous origin of life studies have demonstrated the presence of amino acids and nucleotides in the same prebiotic milieu. In this study, we set out to understand the interplay of amino acids with linear or cyclic nucleotides under prebiotically pertinent reaction conditions, especially for its implications for biomolecular evolution. We characterized the cross-catalytic effect of oligomerization, potentially stemming from the simultaneous presence of these two biochemically important monomers. Qualitative and quantitative analysis indicated the formation of longer AMP oligomers and peptides, with 8-10 fold increase in specific reaction scenarios, when compared to reactions that evaluated the monomer oligomerization in isolation. The reason behind such an increase in yield and length, in case of both the oligomers, was the formation of a reactive intermediate. This aminoacylated-AMP (AMP-aa) resulted from a condensation reaction between the nucleotide and the amino acid. We extended this to other amino acids with different R chain characteristics, to comprehend the properties required for the formation of AMP-aa under our reaction conditions. The nonenzymatic formation of these aminoacylated AMP, which in turn resulted in longer oligomers, indicates the plausibility of the emergence of initial steps involved in a primordial translation system.

biochemistry↗

bioRxiv2024

Multiplexed lifetime imaging of single molecules with a gated single-photon camera

Fluorescence lifetime imaging microscopy (FLIM) is a powerful tool to discriminate fluorescent molecules or probe their nanoscale environment. Traditionally, FLIM uses time-correlated single-photon counting (TCSPC), which is precise but intrinsically low-throughput due to its dependence on point detectors. Although time-gated cameras have demonstrated the potential for high-throughput FLIM in bright samples with dense labeling, their use in single-molecule microscopy has not been explored extensively. Here, we report fast and accurate single-molecule FLIM with a commercial time-gated single-photon camera. Our optimized acquisition scheme achieves single-molecule lifetime measurements with a precision only about three times less than TCSPC, while imaging with a large number of pixels (512x512) allowing for the spatial multiplexing of over 3000 molecules. With this approach, we demonstrate parallelized lifetime measurements of large numbers of labeled pore-forming proteins on supported lipid bilayers, and temporal single-molecule Forster resonance energy transfer measurements at 5-25 Hz. This method holds considerable promise for the advancement of multi-target single-molecule localization microscopy and biopolymer sequencing.

biophysics↗

bioRxiv2024

Biotin based Northern Blotting (BiNoB): A Robust and Efficient Alternative

Advancements in sequencing technology have led to the emergence of diverse types of regulatory RNAs. Differential transcript levels regulate cellular processes and influence disease severity. Identifying these variations through reliable methods is crucial for understanding their regulatory roles and disease mechanisms. Northern blotting, which used to be considered the gold standard for differential expression analysis, poses challenges due to various limitations associated with RNA quality, integrity, radioactivity, reagents, and the expenses associated with it. In this study, we employed a biotin-based Northern blotting approach, BiNoB, which offers advantages over traditional methods. In this study, we comprehensively targeted various RNA types, making this technique a versatile tool for RNA detection. Additionally, we conducted a comparison between 3-end labeled probes, which were labeled in-house, and 5-end labeled probes, which were commercially obtained. Remarkably, the results revealed significantly increased sensitivity with 3-end labeled probes. Furthermore, we prepared an in-house buffer and compared its performance with the commercially available ULTRAhyb buffer, which exhibited comparable sensitivity, indicating that the in-house buffer is a cost-effective alternative. Intriguingly, our findings showed that as little as 1{micro}g of total RNA proved to be adequate for the detection of small RNAs like tRNAs and their derived fragments.

molecular biology↗

bioRxiv2024

Podoplanin Positive Cell-derived Extracellular Vesicles Contribute to Cardiac Amyloidosis After Myocardial Infarction

BackgroundAmyloidosis is a major long-term complication of chronic disease; however, whether it represents one of the complications of post-myocardial infarction (MI) is yet to be fully understood. MethodsUsing wild-type and knocked-out MI mouse models and characterizing in vitro the exosomal communication between bone marrow-derived macrophages and activated mesenchymal stromal cells (MSC) isolated after MI, we investigated the mechanism behind Serum Amyloid A 3 (SAA3) protein overproduction in injured hearts. ResultsHere, we show that amyloidosis occurs after MI and that amyloid fibers are composed of macrophage-derived SAA3 monomers. SAA3 overproduction in macrophages is triggered by exosomal communication from a subset of activated MSC, which, in response to MI, acquire the expression of a platelet aggregation-inducing type I transmembrane glycoprotein named Podoplanin (PDPN). Cardiac MSCPDPN+ communicate with and activate macrophages through their extracellular vesicles or exosomes. Specifically, MSCPDPN+ derived exosomes (MSCPDPN+ Exosomes) are enriched in SAA3 and exosomal SAA3 protein engages with Toll-like receptor 2 (TRL2) on macrophages, triggering an overproduction and impaired clearance of SAA3 proteins, resulting in aggregation of SAA3 monomers as rigid amyloid deposits in the extracellular space. The onset of amyloid fibers deposition alongside extra-cellular-matrix (ECM) proteins in the ischemic heart exacerbates the rigidity and stiffness of the scar, hindering the contractility of viable myocardium and overall impairing organ function. Using SAA3 and TLR2 deficient mouse models, we show that SAA3 delivered by MSCPDPN+ exosomes promotes post-MI amyloidosis. Inhibition of SAA3 aggregation via administration of a retro-inverso D-peptide, specifically designed to bind SAA3 monomers, prevents the deposition of SAA3 amyloid fibrils, positively modulates the scar formation, and improves heart function post-MI. ConclusionOverall, our findings provide mechanistic insights into post-MI amyloidosis and suggest that SAA3 may be an attractive target for effective scar reversal after ischemic injury and a potential target in multiple diseases characterized by a similar pattern of inflammation and amyloid deposition. NOVELTY AND SIGNIFICANCEWhat is known? O_LIAccumulation of rigid amyloid structures in the left ventricular wall impairs ventricle contractility. C_LIO_LIAfter myocardial infarction cardiac Mesenchymal Stromal Cells (MSC) acquire Podoplanin (PDPN) to better interact with immune cells. C_LIO_LIAmyloid structures can accumulate in the heart after chronic inflammatory conditions. C_LI What information does this article contribute? O_LIWhether accumulation of cumbersome amyloid structures in the ischemic scar impairs left ventricle contractility, and scar reversal after myocardial infarction (MI) has never been investigated. C_LIO_LIThe pathophysiological relevance of PDPN acquirement by MSC and the functional role of their secreted exosomes in the context of post-MI cardiac remodeling has not been investigated. C_LIO_LIAmyloid structures are present in the scar after ischemia and are composed of macrophage-derived Serum Amyloid A (SAA) 3 monomers, although mechanisms of SAA3 overproduction is not established. C_LI SUMMARY OF NOVELTY AND SIGNIFICANCEHere, we report that amyloidosis, a secondary phenomenon of an already preexisting and prolonged chronic inflammatory condition, occurs after MI and that amyloid structures are composed of macrophage-derived SAA3 monomers. Frequently studied cardiac amyloidosis are caused by aggregation of immunoglobulin light chains, transthyretin, fibrinogen, and apolipoprotein in a healthy heart as a consequence of systemic chronic inflammation leading to congestive heart failure with various types of arrhythmias and tissue stiffness. Although chronic MI is considered a systemic inflammatory condition, studies regarding the possible accumulation of amyloidogenic proteins after MI and the mechanisms involved in that process are yet to be reported. Here, we show that SAA3 overproduction in macrophages is triggered in a Toll-like Receptor 2 (TLR2)-p38MAP Kinase-dependent manner by exosomal communication from a subset of activated MSC, which, in response to MI, express a platelet aggregation-inducing type I transmembrane glycoprotein named Podoplanin. We provide the full mechanism of this phenomenon in murine models and confirm SAA3 amyloidosis in failing human heart samples. Moreover, we developed a retro-inverso D-peptide therapeutic approach, "DRI-R5S," specifically designed to bind SAA3 monomers and prevent post-MI aggregation and deposition of SAA3 amyloid fibrils without interfering with the innate immune response.

immunology↗

bioRxiv2024

Preclinical study of the human recombinant Erythropoietin (GBPD002) compared with Eprex

Erythropoietin (EPO) is a glycoprotein that an essential growth factor for erythroid progenitors at the bone marrow, which appears in blood as a response to hypoxia. It is produced mainly by the kidneys; and its biosynthesis and release are stimulated by the reduction of tissue oxygenation and/or the reduction of the mass of erythrocytes. Here, we report the results of the preclinical evaluation of the safety of GBPD002 a recombinant human erythropoietin (rhEPO) developed by the Globe Biotech Limited, Bangladesh, through a comparative study of acute toxicity with Eprex(R), a commercial homologue from Janssen, UK. The product was administered subcutaneously into Wistar rats, at 500 lU/kg of therapeutic dose (TD) and 3 times of TD for the single dose toxicity study on 14 consecutive days and 125 UL/kg, 250 UL/kg, 500 UL/kg, 750 UL/kg, 1000 UL/kg, 1250 UL/kg and 1500 UL/kg of GBPD002 and Eprex(R) on 7 consecutive days respectively for the repeated dose toxicity study. Hematological and biochemical parameters were measured for all test subjects before first dose injection and the day after last dose injection of the both studies. Necropsy and histopathology of representative subjects from each group were also observed to find any pathological significance like degeneration or cellular necrosis in internal organs such as kidney, liver, lung and spleen of any rat under experiment. Both GBPD002 and Eprex(R) comparative toxicology studies revealed similar pharmacologically driven mechanisms of toxicity, which is statistically insignificant (p >0.05). Though hematology parameter values stayed within the normal range during the assay period but the high count of hemoglobin and high hematocrit (P<0.05), together with the decrease in white blood cell, confirm the therapeutic effect of Erythropoietin in both studies. Moreover, in both studies, the initial and final values of aspartate aminotransferase, alanine aminotransferase and blood urea nitrogen were also found similar (p >0.05) for both GBPD002 and Eprex(R) in the study. The study clearly established that the toxicological profile of "GBPD002" and Eprex(R), administered subcutaneously, were similar and related to the known pharmacology of erythropoietin alfa; hereby, demonstrating the proof of totality and no residual uncertainty between "GBPD002" and Eprex(R). Therefore, "GBPD002" and Eprex(R) shall be administered interchangeably in relevant indications.

pharmacology and toxicology↗

bioRxiv2024

Exploring the energetic and conformational properties of the sequence space connecting naturally occurring RNA tetraloop receptor motifs

Folded RNAs contain tertiary contact motifs whose structures and energetics are conserved across different RNAs. The transferable properties of RNA motifs simplify the RNA folding problem, but measuring energetic and conformational properties of many motifs remains a challenge. Here, we use a high-throughput thermodynamic approach to investigate how sequence changes alter the binding properties of naturally-occurring motifs, the GAAA tetraloop * tetraloop receptor (TLR) interactions. We measured the binding energies and conformational preferences of TLR sequences that span mutational pathways from the canonical 11ntR to two other natural TLRs, the IC3R and Vc2R. While the IC3R and Vc2R share highly similar energetic and conformational properties, the landscapes that map the sequence changes for their conversion from the 11ntR to changes in these properties differ dramatically. Differences in the energetic landscapes stem from the mutations needed to convert the 11ntR to the IC3R and Vc2R rather than a difference in the intrinsic energetic architectures of these TLRs. The conformational landscapes feature several non-native TLR variants with conformational preferences that differ from both the initial and final TLRs; these species represent potential branching points along the multidimensional sequence space to sequences with greater fitness in other RNA contexts with alternative conformational preferences. Our high-throughput, quantitative approach reveals the complex nature of sequence-fitness landscapes and leads to models for their molecular origins. Systematic and quantitative molecular approaches provide critical insights into understanding the evolution of natural RNAs as they traverse complex landscapes in response to selective pressures.

biophysics↗

bioRxiv2024

H2O2 mediated MAPK-mTOR crosstalk determines the XIAP and FLIP degradation pathways and development of resistance to Imatinib

Abnormal or aggregated proteins degradation is very crucial to protect the cell against proteotoxic stress. Cellular proteins are usually degraded in a ubiquitin-dependent manner by proteasomes and macro-autophagy/autophagy. Both processes use ubiquitin, binding of which target them to proteasomes via ubiquitin-like domains or to phagophores (the precursors to autophagosomes) via Atg8/LC3 binding motifs. Since both pathways use ubiquitin, the question that arises is how degradative pathway choice is achieved. Here in this paper, we have shown that mTOR pathway acts as major player in deciding which degradation pathway to choose. Here, we used Imatinib resistant (K562R) and Imatinib-sensitive (K562S) K562 cell as our previous study showed that Ubiquitin-proteasome pathway is selected for degradation of two proteins XIAP and FLIP in Imatinib-resistant K562 cells. H2O2 treatment in K562R cells degrades XIAP and FLIP via proteasomal pathway whereas H2O2 degrades them via lysosomal pathway in K562S cells. We found H2O2 mediated mTOR activation suppressed autophagy pathway in K562R cells and protein takes proteasomal degradation rout. However, proteins get degraded via autophagy when mTOR remains suppressed in K562S cells. We also found that H2O2-mediated activation of activation of ERK in turn activated mTOR in K562R cells because ROS inhibited ERK phosphorylation and thus mTOR remained inhibited in K562S cells. Moreover, we found that endogenous H2O2 levels are way higher in K562R cells than in K562S cells. Finally, and most interestingly, our data clearly suggested that activation of mTOR is responsible for developing resistance to Imatinib in K562R cells. Thus, this paper delineates a very crucial role of H2O2 and mTOR in both the selection of protein degradation pathway and development of drug resistant.

cancer biology↗

bioRxiv2024

Single Nucleotide Polymorphism (SNP) and Antibody-based Cell Sorting (SNACS): A tool for demultiplexing single-cell DNA sequencing data

MotivationRecently, single-cell DNA sequencing (scDNA-seq) and multi-modal profiling with the addition of cell-surface antibodies (scDAb-seq) have provided key insights into cancer heterogeneity. Scaling these technologies across large patient cohorts, however, is cost and time prohibitive. Multiplexing, in which cells from unique patients are pooled into a single experiment, offers a possible solution. While multiplexing methods exist for scRNAseq, accurate demultiplexing in scDNAseq remains an unmet need. ResultsHere, we introduce SNACS: Single-Nucleotide Polymorphism (SNP) and Antibody-based Cell Sorting. SNACS relies on a combination of patient-level cell-surface identifiers and natural variation in genetic polymorphisms to demultiplex scDNAseq data. We demonstrated the performance of SNACS on a dataset consisting of multi-sample experiments from patients with leukemia where we knew truth from single-sample experiments from the same patients. Using SNACS, accuracy ranged from 0.948 - 0.991 vs 0.552 - 0.934 using demultiplexing methods from the single-cell literature. Availability ImplementationSNACS is available at https://github.com/olshena/SNACS. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=83 SRC="FIGDIR/small/579345v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@1e52aaorg.highwire.dtl.DTLVardef@c51d1dorg.highwire.dtl.DTLVardef@fa68a6org.highwire.dtl.DTLVardef@1ec6bd1_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

bioRxiv2024

IL6 mediated cFLIP downregulation increases the migratory and invasive potential of triple negative breast cancer cell line

c-FLIP (cellular FLICE-Like Inhibitor of Apoptotic protein) which belongs to the negative regulators of the death receptor pathway, control apoptosis in a number of cancers. literatures suggest that its overexpression facilitate cancer progression and also helps in the drug resistance. However, there is a very few data available to show how it control metastasis. Moreover, how cFLIP is regulated during the progression of cancer into advanced stage and its mechanism of action on tumor cell migration and invasion is yet to be known. Our TCGA data analysis has shown that cFLIP is downregulated in many cancers, including breast cancer, especially at the later stages. when, we analysed and compared early-stage breast carcinoma cell line MCF7 (luminal) and advanced stage triple negative cell line MDAMB-231, which is highly metastatic, we found a negative correlation between cFLIP expression and metastasis. Our results indicated that Il6, one of the most prominent cytokines inside tumor microenvironment, activated p38 and the later helped in cFLIP downregulation in MDA-MB-231 cell line. Moreover, we have found that cFLIP negatively regulated autophagy and this autophagy downregulation resulted in decrease in metastasis. Thus, we have shown, for the first time, a complete interconnecting pathway in which IL6 mediated p38 activation directly influences metastasis by regulating autophagy via cFLIP downregulation.

cancer biology↗

bioRxiv2023

Neuronal exosomes transport a miRNA/RISC cargo to preserve germline stem cell integrity during energy stress

During periods of nutrient scarcity, many animals undergo germline quiescence to preserve reproductive capacity, and neurons are often necessary for this adaptation. We show here that starvation causes the release of neuronal miRNA/Argonaute-loaded exosomes following AMPK-regulated trafficking changes within serotonergic neurons. This neuron-to-germ line communication is independent of classical serotonergic neurotransmission, but instead relies on endosome-derived vesicles that carry a pro-quiescent miRNA cargo to modify germline gene expression. Using a miRNA activity sensor, we show that neuronally-expressed miRNAs can extinguish the expression of germline-mRNA targets in an exosome-dependent manner. Our findings demonstrate how an adaptive neuronal response can change gene expression at a distance by re-directing intracellular trafficking to release neuronal exosomes with specific miRNA cargos capable of tracking to their appropriate destinations. One Sentence SummaryNeurons release miRNA Argonaute-containing exosomes to establish germline stem cell quiescence in response to energy stress.

developmental biology↗

bioRxiv2023

Long-term cold adaptation leads to increased thermal plasticity of male body size and thermal canalization of fecundity in populations of Drosophila melanogaster: an experimental evolution study

From laboratory populations of Drosophila melanogaster maintained at 25{degrees}C for many decades, new populations were derived and maintained at 17{degrees}C for over 60 generations. Fitness traits such as body size and fecundity of the cold and warm selected populations were quantified at both 17{degrees}C and 25{degrees}C. Flies from both selection regimes had similar body weight when grown at 25{degrees}C, but 17{degrees}C selected males had greater dry weight and less relative water content than 25{degrees}C selected males, when grown at 17{degrees}C. Cold selected males thus evolved greater thermal plasticity of body weight and density compared to controls. Fecundity data showed, 25{degrees}C selected females laid less eggs at 17{degrees}C compared to 25{degrees}C treatment, but 17{degrees}C selected females did not show significant difference in fecundity between 25{degrees}C and 17{degrees}C. Cold evolved flies thus showed thermal canalization of fecundity, possibly buffering the repressing effect of cold. Whether or not (i) greater body mass and density of cold evolved males, and (b) unrepressed fecundity of cold evolved females, both observed when reared at cold, are causally related, remain to be investigated. The study thus shows thermal selection can lead to evolution of greater thermal plasticity in a trait, while result in thermal canalization of another.

evolutionary biology↗

bioRxiv2023

AMPK regulates small RNA pathway prevalence to mediate soma-to-germ line communication and establish germline stem cell quiescence

It is well established that cells communicate with each other via signaling molecules and pathways. Recent work has further indicated that this transfer of information can breach the soma-to-germ line barrier, thus permitting changes in germline gene expression in response to cellular decisions made in somatic lineages. We show that during periods of extended energy stress AMPK alters small RNA biogenesis in somatic cells, which non-autonomously regulates the quiescence of germline stem cells. By combining both genetic analyses and a novel method of miRNA imaging, we show that AMPK-mediated phosphorylation acts as a molecular switch that drives the re-allocation of the key RNA endonuclease Dicer to the miRNA synthesis pathway during the dauer stage of C. elegans. By modifying Dicer and other components of the miRNA synthesis machinery, AMPK fine-tunes the production of a population of somatic miRNAs that act as a "pro-quiescence" signal to maintain germline integrity during periods of extended energy stress, thus bridging the gap between the soma and the germ line by altering small RNA homeostasis.

molecular biology↗

bioRxiv2023

E-proteins set the threshold for optimal TCF1 expression during αβ T cell development.

Expression of T Cell Factor-1 (TCF1), encoded by Tcf7, regulates lineage fate decisions during T cell development. Here we demonstrate that E-proteins control the threshold of TCF1 expression required for development of T cells. E-proteins bind to five elements (EPEs) in the Tcf7 locus. The third element, EPE3, interacts directly with Tcf7 promoter in Hi-ChIP analyses, suggesting it is an active enhancer. CRISPR-ablation of EPE3 reduces TCF1 protein expression in precursor thymocytes by 2-fold and dramatically impairs development of {beta} and {gamma}{delta} T cells. Single cell gene expression analysis identified differentiation blocks at multiple CD4-CD8- stages and subsequent transition to CD4+CD8+ stage. These data identify E-proteins and EPE3 as critical for the optimal TCF1 expression required for T cell development.

immunology↗

bioRxiv2023

Rationalised experiment design for parameter estimation with sensitivity clustering

Quantitative experiments are essential for investigating, uncovering and confirming our understanding of complex systems, necessitating the use of effective and robust experimental designs. Despite generally outperforming other approaches, the broader adoption of model-based design of experiments (MBDoE) has been hindered by oversimplified assumptions and computational overhead. To address this, we present PARameter SEnsitivity Clustering (PARSEC), an MBDoE framework that identifies informative measurable combinations through parameter sensitivity (PS) clustering. We combined PARSEC with a new variant of Approximate Bayesian Computation for rapid, automated assessment and ranking of designs. By inherent design, PARSEC can take into account experimental restrictions and parameter variability. We show that PARSEC improves parameter estimation for two different types of biological models. Importantly, PARSEC can determine the optimal sample size for information gain, which we show correlates well with the optimal number of PS clusters. This supports our rationale for PARSEC and demonstrates the potential to harness both model structure and system behaviour to efficiently navigate the experiment design space.

bioinformatics↗

bioRxiv2023

Determining the shelf life of an erythropoietin alfa biosimilar GBPD002 through stability study

GBPD002 is a recombinant human erythropoietin (rhEPO) produced by recombinant DNA technology using mammalian cell expression system. In this study, samples were analyzed according to current Good Laboratory Practice (cGLP) and regulatory guidelines to evaluate the quality of the product under the influence of variety of environmental factors in a time-dependent manner. Accelerated (25 {+/-} 2 {degrees}C and relative humidity: 60 {+/-} 5 %) and real-time (5 {+/-} 3 {degrees}C) stability study were conducted up to 6 months and 12 months, respectively; samples were analyzed in every 3 months. After 12 months, real-time stability studies were performed with 6 months interval up to18 months, which to be continued up to 24 months. Appearance and pH were assessed using standard methods, and molecular weight was determined by Western blotting. Chromatographic identification and quantitative assays were performed by reversed- phase chromatography (RPC). High-molecular weight aggregatesand degradants were determined using size exclusion chromatography (SEC) and particle size distribution (PSD) analysis. Biofunctionality of the samples were evaluated by in vitro and in vivo bioassays. Bacterial endotoxin and sterility test were performed as safety parameters. All samples met the acceptance criteria, and the data were extrapolated using the regulatory guideline to determine the shelf life. The data revealed that the GBPD002 is stable up to 24 months.

pharmacology and toxicology↗