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Jacobson, A.

Publications and source records attributed to Jacobson, A..

At least 19 recordsLinked to original sources
bioRxiv2026

Preclinical evaluation of Brincidofovir in glioblastoma demonstrates improved long term-survival and cytomegalovirus-dependent and independent effects

Cytomegalovirus (CMV) has been implicated in glioblastoma (GBM) progression. Ongoing clinical trials are assessing therapeutic approaches targeting CMV in GBM but to date no new therapy has been approved outside the standard of care. Previous preclinical studies have highlighted the potential of the antiviral drug Cidofovir (CDV) in GBM; however, its clinical use is limited by dose-dependent nephrotoxicity and poor cellular uptake, necessitating high intravenous doses to achieve therapeutic activity. Brincidofovir (BCV), a lipid conjugate of CDV has been developed, which does not induce nephrotoxicity and has significantly greater cellular bioavailability. Here we examined the effects of BCV in a newly established CMV-driven GBM model (SB28) and in patient-derived tumor neurospheres. We show that BCV prolongs survival in vivo and exerts both CMV-dependent and independent antitumor effects. Mechanistically, BCV induces DNA damage and cell cycle dysregulation in GBM cells and inhibits proliferation of patient-derived neurospheres in a dose-dependent manner. These data identify BCV as a dual-action therapeutic that suppresses viral oncomodulation while directly targeting tumor cell viability.

cancer biology↗
bioRxiv2026

Phantom- and simulation-based validation of combined diffusion relaxometry in ex vivo ADRD white matter

PurposeIn principle, combined T2-Diffusion (D) MRI has the microstructural and chemical sensitivity to detect axonal and myelin water changes in Alzheimers disease and related dementias (ADRD), but its practical implementation may be hindered by demanding hardware requirements. This work assesses the feasibility and accuracy of T2-D for ex vivo analysis of WM lesions in ADRD tissue. MethodsA thawed ex vivo brain sample from the Michigan Brain Bank and a T2-D phantom were scanned at 7T using a combined diffusion relaxometry (CDR) sequence. A non-negative least squares (NNLS) conventional data processing pipeline was used to disentangle water pools with unique T2-D signatures. Simulations examined the effects of minimum TE and SNR on recovery of myelin water (short T2, slow diffusion). ResultsAcross tissue types, T2-D data consistently resolved three spectral components. Phantom experiments showed detection of short T2 and slow diffusion features similar to those observed in ADRD ex vivo tissue, and confirmed CDRs ability to accurately resolve multiple components. Simulations indicated reliable T2-D recovery for myelin with SNR > 30 dB and minimum TE < 25 ms. ConclusionStrong T2 and D weighting could be combined to capture the expected axonal, myelin, and extracellular (EC) regions in T2-D space. The observed short-T2, restricted-D components are therefore unlikely to be artifacts and instead support interpretations as physically meaningful myelin and axonal water signatures.

bioengineering↗
bioRxiv2025

Impact of Tissue Sample Preparation Methods on Myelin-Sensitive Quantitative MR Imaging

PurposeValidation of quantitative MRI (qMRI) parameters with histology is often done with ex vivo fixed tissue samples. Freezing is another common form of tissue preservation, but the effects of freezing and thawing tissue on myelin-sensitive quantitative MRI parameters and their correlation with histology require further analysis. MethodsMyelin water imaging, off-resonance RF saturation magnetization transfer (MT), and selective inversion recovery MT MRI experiments were conducted on 14 fresh, thawed, and fixed sheep brain tissue samples to calculate various surrogate measures of myelin content. These measures were compared with luxol fast blue (LFB) histological stain results. ResultsFresh, thawed, and fixed tissue qMRI values correlated well with LFB. Thawed and fixed tissue exhibited modest increases, between 3-32%, for most qMRI parameter values compared to fresh. Histology results showed that thawed samples did not lose tissue integrity from the freezing process. ConclusionFreezing is a reasonable alternative tissue preservation method to fixation for use in qMRI analysis, but may differentially affect qMRI parameter values in regions with varying myelin content.

bioengineering↗
bioRxiv2023

Structural mechanism of angiogenin activation by the ribosome

Angiogenin, an RNase A-family protein, promotes angiogenesis and has been implicated in cancer, neurodegenerative diseases, and epigenetic inheritance. Upon activation during cellular stress, angiogenin cleaves tRNAs at the anticodon loop, producing nicked tRNA (also known as tRNA halves, tiRNAs or tsRNAs) and resulting in translation repression. The catalytic activity of isolated angiogenin, however, is very low, and the mechanisms of the enzyme activation and tRNA specificity have remained a puzzle. Here, we uncover these mechanisms using biochemical assays and cryogenic electron microscopy. Our work reveals that the cytosolic ribosome is the long-sought activator of angiogenin. A 2.8-[A] resolution cryo-EM structure features angiogenin bound in the A site of the 80S ribosome. The C-terminal tail of angiogenin is rearranged by interactions with the ribosome to activate the RNase catalytic center, making the enzyme several orders of magnitude more efficient in tRNA cleavage. Additional 80S*angiogenin structures capture how the tRNA substrate is directed by the ribosome next to angiogenins active site, demonstrating that the ribosome acts as the specificity factor. Our findings therefore suggest that angiogenin is activated by ribosomes with a vacant A site, whose abundance increases during cellular stresses.

biochemistry↗
bioRxiv2023

Lung-innervating neurons expressing Tmc3 can induce broncho-constriction and dilation with direct consequences for the respiratory cycle

Sensory neurons of the vagal ganglia (VG) innervate lungs and play a critical role in maintaining airway homeostasis. However, the specific VG neurons that innervate lungs, and the mechanisms by which these neurons sense and respond to airway insults, are not well understood. Here, we identify a subpopulation of lung-innervating VG neurons defined by their expression of Tmc3. Single cell transcriptomics illuminated several subpopulations of Tmc3+ sensory neurons, revealing distinct Piezo2- and Trpv1-expressing subclusters. Furthermore, Tmc3 deficiency in VG neurons leads to global and subcluster specific transcriptional changes related to metabolic and ion channel function. Importantly, we show that broncho-constriction and dilation can be modulated through inhibition or activation of Tmc3+ VG neurons resulting in a decrease or increase of end-expiratory lung volume, respectively. Together, our data show that Tmc3 is a marker of lung-innervating neurons and may play a pivotal role in maintaining fundamental inspiratory and expiratory processes. SignificanceHarnessing the neuronal mechanisms that regulate lung function offers potential alternatives to existing corticosteroid treatment regimens for respiratory illness associated with acute bronchoconstriction including asthma, COPD, and emphysema. Our findings define Transmembrane channel-like 3, Tmc3, as a marker of lung-innervating sensory neurons, identify distinct subpopulations of Tmc3+ neurons with unique transcriptional profiles, and show that activation or inhibition of these neurons has a significant impact on airway function. Our work highlights potential avenues of novel targeted intervention in respiratory conditions driven by dysfunctional neuronal reflexes.

neuroscience↗
bioRxiv2023

Direct and indirect consequences of PAB1 deletion in the regulation of translation initiation, translation termination, and mRNA decay

Cytoplasmic poly(A)-binding protein (PABPC; Pab1 in yeast) is thought to be involved in multiple steps of post-transcriptional control, including translation initiation, translation termination, and mRNA decay. To understand these roles of PABPC in more detail for endogenous mRNAs, and to distinguish its direct effects from indirect effects, we have employed RNA-Seq and Ribo-Seq to analyze changes in the abundance and translation of the yeast transcriptome, as well as mass spectrometry to assess the abundance of the components of the yeast proteome, in cells lacking the PAB1 gene. We observed drastic changes in the transcriptome and proteome, as well as defects in translation initiation and termination, in pab1{Delta} cells. Defects in translation initiation and the stabilization of specific classes of mRNAs in pab1{Delta} cells appear to be partly indirect consequences of reduced levels of specific initiation factors, decapping activators, and components of the deadenylation complex in addition to the general loss of Pab1s direct role in these processes. Cells devoid of Pab1 also manifested a nonsense codon readthrough phenotype indicative of a defect in translation termination, but this defect may be a direct effect of the loss of Pab1 as it could not be attributed to significant reductions in the levels of release factors. AUTHOR SUMMARYMany human diseases are caused by having too much or too little of certain cellular proteins. The amount of an individual protein is influenced by the level of its messenger mRNA (mRNA) and the efficiency of translation of the mRNA into a polypeptide chain by the ribosomes. Cytoplasmic poly(A)-binding protein (PABPC) plays numerous roles in the regulation of this multi-staged process, but understanding its specific role has been challenging because it is sometimes unclear whether experimental results are related to PABPCs direct role in a specific biochemical process or to indirect effects of its other roles, leading to conflicting models of PABPCs functions between studies. In this study, we characterized defects of each stage of protein synthesis in response to loss of PABPC in yeast cells by measuring whole-cell levels of mRNAs, ribosome-associated mRNAs, and proteins. We demonstrated that defects in most steps of protein synthesis other than the last can be explained by reduced levels of mRNAs that code for proteins important for that step in addition to loss of PABPCs direct role on that step. Our data and analyses serve as resources for the design of future studies of PABPCs functions.

molecular biology↗
bioRxiv2022

Vector acquisition and co-inoculation of two plant viruses influences transmission, infection, and replication in new hosts

This study investigated the role of vector acquisition and transmission on the propagation of single and co-infections of tomato yellow leaf curl virus (TYLCV,) and tomato mottle virus (ToMoV) (Family: Geminiviridae, Genus: Begomovirus) by the whitefly vector Bemisia tabaci MEAM1 (Gennadius) in tomato. The aim of this research was to determine if how viruses are co-acquired and co-transmitted changes the probability of acquisition, transmission and new host infections. Whiteflies acquired virus by feeding on singly infected plants, co-infected plants, or by sequential feeding on singly infected plants. Viral titers were also quantified by qPCR in vector cohorts, in artificial diet, and plants after exposure to viruliferous vectors. Differences in transmission, infection status of plants, and titers of TYLCV and ToMoV were observed among treatments. All vector cohorts acquired both viruses, but co-acquisition/co-inoculation generally reduced transmission of both viruses as single and mixed infections. Co-inoculation of viruses by the vector also altered virus accumulation in plants regardless of whether one or both viruses were propagated in new hosts. These findings highlight the complex nature of vector-virus-plant interactions that influence the spread and replication of viruses as single and co-infections.

plant biology↗
bioRxiv2022

High-resolution cross-species transcriptomic atlas of dorsal root ganglia reveals species-specific programs for sensory function

Sensory neurons of the dorsal root ganglion (DRG) play a crucial role in maintaining tissue homeostasis by sensing and initiating responses to stimuli. While most preclinical studies of DRGs are conducted in rodents, much less is known about the mechanisms of sensory perception in primates. We generated a transcriptome atlas of mouse, guinea pig, cynomolgus monkey, and human DRGs using a framework that implements a common laboratory workflow and multiple data-integration approaches to generate high-resolution cross-species mappings of sensory neuron subtypes. Using our atlas, we identified conserved core modules highlighting subtype-specific biological processes related to inflammatory response. We also identified divergent expression of key genes involved in DRG function, suggesting species-specific adaptations. Among these, we validated that Tafa4, a member of the druggable genome, was expressed in distinct populations of DRG neurons across species, highlighting species-specific programs that are critical for therapeutic development.

neuroscience↗
bioRxiv2022

Gut commensal bacteria enhance pathogenesis of a tumorigenic murine retrovirus

The influence of the microbiota on viral transmission and replication is well appreciated. However, its impact on retroviral pathogenesis outside of transmission/replication control remained unknown. Using Murine Leukemia Virus (MuLV), we found that some commensal bacteria promoted the development of leukemia induced by this retrovirus. The promotion of leukemia development by commensals was due to suppression of the adaptive immune response through upregulation of several negative regulators of immunity. These negative regulators included Serpinb9b and Rnf128, which are associated with a poor prognosis of some spontaneous human cancers. Upregulation of Serpinb9b was mediated by sensing of bacteria by NOD1/NOD2/RIPK2 pathway. This work describes a novel mechanism by which the microbiota enhances tumorigenesis within gut-distant organs and points at potential new targets for cancer therapy.

microbiology↗
bioRxiv2021

Progressive polysomal association of Upf1, Upf2, and Upf3 as ribosomes traverse mRNA coding regions

Upf1, Upf2, and Upf3 are the central regulators of nonsense-mediated mRNA decay (NMD), the eukaryotic mRNA quality control pathway generally triggered when a premature termination codon is recognized by the ribosome. The NMD-related functions of the Upf proteins likely commence while these factors are ribosome-associated, but little is known of the timing of their ribosome binding, their specificity for ribosomes translating NMD substrates, or the nature and role of any ribosome:Upf complexes. Here, we have elucidated details of the ribosome-associated steps of NMD. By combining yeast genetics with selective ribosome profiling and co-sedimentation analyses of polysomes with wild-type and mutant Upf proteins, our approaches have identified distinct states of ribosome:Upf association. All three Upf factors manifest progressive polysome association as mRNA translation proceeds, but these events appear to be preceded by formation of a Upf1:80S complex as mRNAs initiate translation. This complex is likely executing an early mRNA surveillance function.

molecular biology↗
bioRxiv2021

Affinity sedimentation and magnetic separation with plant-made immunosorbent nanoparticles for therapeutic protein purification

The virus-based immunosorbent nanoparticle is a nascent technology being developed to serve as a simple and efficacious agent in biosensing and therapeutic antibody purification. There has been particular emphasis on the use of plant virions as immunosorbent nanoparticle chassis for their diverse morphologies and accessible, high yield manufacturing via crop cultivation. To date, studies in this area have focused on proof-of-concept immunosorbent functionality in biosensing and purification contexts. Here we consolidate a previously reported pro-vector system into a single Agrobacterium tumefaciens vector to investigate and expand the utility of virus-based immunosorbent nanoparticle technology for therapeutic protein purification. We demonstrate the use of this technology for Fc-fusion protein purification, characterize key nanomaterial properties including binding capacity, stability, reusability, and particle integrity, and present an optimized processing scheme with reduced complexity and increased purity. Furthermore, we present a coupling of virus-based immunosorbent nanoparticles with magnetic particles as a strategy to overcome limitations of the immunosorbent nanoparticle sedimentation-based affinity capture methodology. We report magnetic separation results which exceed the binding capacity of current industry standards by an order of magnitude.

bioengineering↗
bioRxiv2021

Dcp2 C-terminal Cis-Binding Elements Control Selective Targeting of the Decapping Enzyme by Forming Distinct Decapping Complexes

A single Dcp1-Dcp2 decapping enzyme targets diverse classes of yeast mRNAs for decapping-dependent 5 to 3 decay, but the molecular mechanisms controlling selective mRNA targeting by the enzyme remain elusive. Through extensive genetic analyses we uncover cis-regulatory elements in the Dcp2 C-terminal domain that control selective targeting of the decapping enzyme by forming distinct decapping complexes. Two Upf1-binding motifs target the decapping enzyme to NMD substrates, and a single Edc3-binding motif targets both Edc3 and Dhh1 substrates. Pat1-binding leucine-rich motifs target Edc3 and Dhh1 substrates under selective conditions. Although it functions as a unique targeting component of specific complexes, Edc3 is a common component of multiple complexes. Xrn1 also has a specific Dcp2 binding site, allowing it to be directly recruited to decapping complexes. Collectively, our results demonstrate that Upf1, Edc3, and Pat1 function as regulatory subunits of the holo-decapping enzyme, controlling both its targeting specificity and enzymatic activation. HighlightsLoss of Dcp2 cis-binding elements causes selective stabilization of distinct decapping substrates Dcp2 cis-binding elements promote the assembly of target-specific decapping complexes in vivo Xrn1 binds to Dcp2, and both Edc3 and Xrn1 are common components of multiple decapping complexes Upf1, Edc3, and Pat1 function as unique targeting subunits of the yeast holo-decapping enzyme

molecular biology↗
bioRxiv2021

Pvr and downstream signaling factors are required for spreading of Drosophila hemocytes at larval wound sites

Tissue injury is typically accompanied by inflammation. In Drosophila melanogaster, wound-induced inflammation involves adhesive capture of hemocytes at the wound surface followed by hemocyte spreading to assume a flat, lamellar morphology. The factors that mediate this cell spreading at the wound site are not known. Here, we discover a role for the Platelet-derived growth factor (PDGF)/ Vascular endothelial growth factor (VEGF)-related receptor (Pvr) and its ligand, Pvf1, in blood cell spreading at the wound site. Pvr and Pvf1 are required for spreading in vivo and in an in vitro spreading assay where spreading can be directly induced by Pvf1 application or by constitutive Pvr activation. In an effort to identify factors that act downstream of Pvr, we performed a genetic screen in which select candidates were tested to determine if they could suppress the lethality of Pvr overexpression in the larval epidermis. Some of the suppressors identified are required for epidermal wound closure, another Pvr-mediated wound response, some are required for hemocyte spreading in vitro, and some are required for both. One of the downstream factors, Mask, is also required for efficient wound-induced hemocyte spreading in vivo. Our data reveals that Pvr signaling is required for wound responses in hemocytes (cell spreading) and defines distinct downstream signaling factors that are required for either epidermal wound closure or hemocyte spreading.

genetics↗
bioRxiv2021

Population diversity of cassava mosaic begomoviruses increases over the course of serial vegetative propagation

Cassava mosaic disease (CMD) represents a serious threat to cassava, a major root crop for more than 300 million Africans. CMD is caused by single-stranded DNA begomoviruses that evolve rapidly, making it challenging to develop durable disease resistance. In addition to the evolutionary forces of mutation, recombination, and reassortment, factors such as climate, agriculture practices, and the presence of DNA satellites may impact viral diversity. To gain insight into the factors that alter and shape viral diversity in planta, we used high-throughput sequencing to characterize the accumulation of nucleotide diversity after inoculation of infectious clones corresponding to African cassava mosaic virus (ACMV) and East African cassava mosaic Cameroon virus (EACMCV) in the susceptible cassava landrace Kibandameno. We found that vegetative propagation had a significant effect on viral nucleotide diversity, while temperature and a satellite DNA did not have measurable impacts in our study. EACMCV diversity increased linearly with the number of vegetative propagation passages, while ACMV diversity increased for a time and then decreased in later passages. We observed a substitution bias toward C[->]T and G[->]A for mutations in the viral genomes consistent with field isolates. Non-coding regions excluding the promoter regions of genes showed the highest levels of nucleotide diversity for each genome component. Changes in the 5 intergenic region of DNA-A resembled the sequence of the cognate DNA-B sequence. The majority of nucleotide changes in coding regions were non-synonymous, most with predicted deleterious effects on protein structure, indicative of relaxed selection pressure over 6 vegetative passages. Overall, these results underscore the importance of knowing how cropping practices affect viral evolution and disease progression.

plant biology↗
bioRxiv2020

Transcriptome-wide investigation of stop codon readthrough in Saccharomyces cerevisiae

Translation of mRNA into a polypeptide is terminated when the release factor eRF1 recognizes a UAA, UAG, or UGA stop codon in the ribosomal A site and stimulates nascent peptide release. However, stop codon readthrough can occur when a near-cognate tRNA outcompetes eRF1 in decoding the stop codon, resulting in the continuation of the elongation phase of protein synthesis. At the end of a conventional mRNA coding region, readthrough allows translation into the mRNA 3-UTR. Previous studies with reporter systems have shown that the efficiency of termination or readthrough is modulated by cis-acting elements other than stop codon identity, including two nucleotides 5 of the stop codon, six nucleotides 3 of the stop codon in the ribosomal mRNA channel, and stem-loop structures in the mRNA 3-UTR. It is unknown whether these elements are important at a genome-wide level and whether other mRNA features proximal to the stop codon significantly affect termination and readthrough efficiencies in vivo. Accordingly, we carried out ribosome profiling analyses of yeast cells expressing wild-type or temperature-sensitive eRF1 and developed bioinformatics strategies to calculate readthrough efficiency, and to identify mRNA and peptide features which influence that efficiency. We found that the stop codon (nt +1 to +3), the nucleotide after it (nt +4), the codon in the P site (nt -3 to -1), and 3-UTR length are the most influential features in the control of readthrough efficiency, while nts +5 to +9 and mRNA secondary structure in the 3-UTR had milder effects. Additionally, we found low readthrough genes to have shorter 3-UTRs compared to high readthrough genes in cells with thermally inactivated eRF1, while this trend was reversed in wild-type cells. Together, our results demonstrated the general roles of known regulatory elements in genome-wide regulation and identified several new mRNA or peptide features affecting the efficiency of translation termination and readthrough. AUTHOR SUMMARYOf the 64 codons that exist for translation of the genetic code into a polypeptide chain, only UAA, UAG, and UGA signify termination of continued protein synthesis. However, the efficiency of termination is not the same for different mRNAs and is likely influenced by mRNA sequences proximal to these "stop" codons. Here, we sought to expand current understanding of termination efficiency to a genome-wide scale. Our analysis identifies novel mRNA features that may regulate the efficiency of translation termination, including the identities of the stop codon, the penultimate codon, the proximal nucleotides, and the length of mRNA 3-untranslated region. As [~]11% of human diseases are caused by mutations that introduce premature stop codons, resulting in both accelerated mRNA decay and truncated protein product, our findings are valuable for understanding and developing therapeutics targeting the termination step of mRNA translation.

genetics↗
bioRxiv2020

The DHODH Inhibitor PTC299 Arrests SARS-CoV-2 Replication and Suppresses Induction of Inflammatory Cytokines

The coronavirus disease 2019 (COVID-19) pandemic has created an urgent need for therapeutics that inhibit the SARS-CoV-2 virus and suppress the fulminant inflammation characteristic of advanced illness. Here, we describe the anti-COVID-19 potential of PTC299, an orally available compound that is a potent inhibitor of dihydroorotate dehydrogenase (DHODH), the rate-limiting enzyme of the de novo pyrimidine biosynthesis pathway. In tissue culture, PTC299 manifests robust, dose-dependent, and DHODH-dependent inhibition of SARS CoV-2 replication (EC50 range, 2.0 to 31.6 nM) with a selectivity index >3,800. PTC299 also blocked replication of other RNA viruses, including Ebola virus. Consistent with known DHODH requirements for immunomodulatory cytokine production, PTC299 inhibited the production of interleukin (IL)-6, IL-17A (also called IL-17), IL-17F, and vascular endothelial growth factor (VEGF) in tissue culture models. The combination of anti-SARS-CoV-2 activity, cytokine inhibitory activity, and previously established favorable pharmacokinetic and human safety profiles render PTC299 a promising therapeutic for COVID-19.

immunology↗
bioRxiv2020

Deep learning neural network prediction method improves proteome profiling of vascular sap of grapevines during Pierce's disease development

Plant secretome studies have shown the importance of plant defense proteins in the vascular system against pathogens. Studies on Pierces disease of grapevines caused by the xylem-limited bacteria Xylella fastidiosa (Xf) have detected proteins and pathways associated to its pathobiology. Despite the biological importance of the secreted proteins in the extracellular space to plant survival and development, proteome studies are scarce due to technical and technological challenges. Deep learning neural network prediction methods can provide powerful tools for improving proteome profiling by data-independent acquisition (DIA). We aimed to explore the potential of this strategy by combining it with in silico spectral library prediction tool, Prosit, to analyze the proteome of vascular leaf sap of grapevines with Pierces disease. The results demonstrate that the combination of DIA and Prosit increased the total number of identified proteins from 145 to 360 for grapevines and 18 to 90 for Xf. The new proteins increased the range of molecular weight, assisted on the identification of more exclusive peptides per protein, and increased the identification of low abundance proteins. These increases allowed the identification of new functional pathways associated with cellular responses to oxidative stress to be further investigated.

genomics↗