Biology subjects

Ferrari, M.

Publications and source records attributed to Ferrari, M..

17 recordsLinked to original sources

bioRxiv2026

The COVID-19 RNA vaccine SpikevaxTM transfects human umbilical endothelial cells and induces Spike protein production, inflammation and leukocyte adhesion

Endothelial cell dysfunction plays a key role in the pathogenesis of severe and critical COVID-19, leading to a multi-systemic inflammatory disease, and results from the direct interaction of the SARS-CoV-2 Spike proteins with endothelial cells. COVID-19 RNA vaccines encode a recombinant SARS-CoV-2 Spike protein which undergoes systemic biodistribution. No information is however so far available on the direct effects of COVID-19 RNA vaccines on human endothelial cells. In the present study, we exposed cultured human umbilical venous endothelial cells (HUVEC) to the COVID-19 RNA vaccine SpikevaxTM (Moderna, Inc.), and thereafter we measured the expression of the Spike protein, of the proinflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-, of the adhesion molecules intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), as well as the attachment of human leukocytes to HUVEC layers. We also assessed the effects of SpikevaxTM on HUVEC viability. Exposure of HUVEC to the COVID-19 RNA vaccine SpikevaxTM resulted in effective cell transfection, and subsequent production of the Spike protein, which was expressed in the cells and secreted in the culture medium. Spike protein production was accompanied by increased gene expression of IL-6 and TNF- and of ICAM-1 and VCAM-1, as well as by increased attachment of leukocytes to HUVEC monolayers. Exposure to the COVID-19 RNA vaccine SpikevaxTM did not affect HUVEC viability. Our results provide a mechanistic explanation to post-COVID-19 RNA vaccination pathologies resulting from endothelial dysfunction, such as during atherosclerosis, autoimmune inflammation, and systemic inflammatory conditions.

pharmacology and toxicology↗

bioRxiv2026

The plant specific Histone Lysine Demethylase MtPKDM9B mediates the root nodule symbiosis by controlling H3K27me3 levels and expression of symbiotic genes

Under nitrogen limiting conditions, legume plants interact with nitrogen fixing bacteria known as rhizobia, resulting in the formation of a new organ, the nodule. This process is accompanied by dramatic changes in gene expression, which operate at different levels. A previous study revealed that histone methylation is differentially modulated during nodulation. However, the histone methyl transferases and demethylases involved in this modulation have not been characterized. In this study we report the identification of the Medicago truncatula putative histone lysine demethylase MtPKDM9B, which is subject to alternative splicing (AS), and the differential modulation of AS variants at translational level during nodule symbiosis. Knockdown of MtPKDM9B impaired infection by rhizobia, nodule development, bacterial viability and the expression of the leghemoglobin coding gene MtLHB1. MtPKDM9B is the putative ortholog of Arabidopsis EARLY FLOWERING 6 (ELF6/AtPKDM9B) gene involved in the removal of the repressive mark H2K27me3. A combination of ChIP-seq and RNA-seq experiments revealed that MtPKDM9B is required for demethylation of H3K27me3 in regions nearby or contained within gene bodies of symbiotic genes and the upregulation of the cognate mRNAs in response to rhizobia, including those encoding the putative ubiquitin ligase MtPUB2, the MYB transcription factor MtMYB040 and the auxin conjugating enzyme MtGH3 (Gretchen Hagen 3). Our findings illustrate how AS and translational regulation of this plant specific histone lysine demethylase contributes to the removal of the repressive mark H3K27me3, promoting transcriptional activation of symbiotic genes required for the formation of functional nitrogen fixing nodules.

plant biology↗

bioRxiv2026

EFFECT OF A BIORESONANCE DEVICE ON VIABILITY AND METABOLIC ACTIVITY IN HUMAN UMBILICAL VENOUS ENDOTHELIAL CELLS

The present study was aimed at evaluating the effects of the bioresonance (BR)-based device QDOME MINI PERSONAL, produced by the society QMED SWISS SA (Lugano, CH), on the viability and mitochondrial metabolic activity of cultured human umbilical venous endothelial cells (HUVEC). To this end, HUVEC were cultured under standard conditions and exposed for 24 h to an "active" or to a mock BR device, in resting conditions and during treatment with H2O2 at the concentration of 500 M, added at the beginning of the 24 h period. The personnel who performed the experiments, collected, and analysed the data was unaware of which device was "active" and which was mock. At the end of the culture, HUVEC were harvested and evaluated for viability and mitochondrial metabolic activity by means of the Trypan Blue exclusion and the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide reduction method, respectively. Under control conditions, viability and mitochondrial metabolic activity were not different in HUVEC exposed to the "active" or to the mock device. HUVEC viability, however, was significantly reduced by exposure to H2O2 in samples exposed to the mock device but not in those exposed to the "active" device. HUVEC mitochondrial metabolic activity was significantly reduced by exposure to H2O2 in both samples exposed to the "active" and to the mock device, however reduction was significantly less in samples exposed to the "active" device. In conclusion, exposure to the BR-based device QDOME MINI PERSONAL, produced by the society QMED SWISS SA (Lugano, CH), prevented the H2O2-induced reduction of viability and reduced the H2O2-induced impairment of mitochondrial metabolic activity in cultured HUVEC.

cell biology↗

bioRxiv2026

CAR T cell therapy selectively depletes disease-driving mutant calreticulin cells in xenotransplants and human organoid models of myelofibrosis

Targeted immunotherapies have revolutionized outcomes for lymphoid malignancies, but success in myeloid neoplasms is limited by the lack of amenable targets and immunologically hostile tumor microenvironment (TME). Myeloproliferative neoplasms are chronic myeloid blood cancers, a third of which are driven by mutations in calreticulin (mutCALR). This yields a common neoepitope that binds to, and activates, the thrombopoietin receptor and results in display of the oncoprotein on the extracellular membrane of disease-driving cells, exposing a therapeutic vulnerability. Here, we present a first-in-class chimeric antigen receptor (CAR) T-cell therapy that specifically targets mutCALR+ cells, both in vitro and in vivo. The CAR T-cell therapy selectively depleted mutCALR+ stem cells from patients with myelofibrosis while sparing healthy stem cells, and improved survival in mutCALR leukemia xenografts. To mimic myelofibrotic marrow, we developed a bespoke human chimeroid model and showed no decrease in the potency of CAR T cell-mediated target cell killing even in a fibrotic tumor microenvironment. We also devised a method to boost cell surface expression of mutCALR in CD34+ cells isolated from patients with accelerated/blast phase MPN (defined as >10 % blasts in peripheral blood or bone marrow), enhancing CAR T targeting. This study presents a therapeutic with potential to eradicate mutCALR-driven malignancies and highlights an innovative strategy to evaluate blood cancer-targeting immunotherapies in a relevant TME. One Sentence SummaryA first-in-class CAR T-cell therapy targeting mutant calreticulin selectively depletes malignant stem cells in vivo and in fibrotic human organoids.

cancer biology↗

bioRxiv2025

BRCA2 reversion mutation-independent resistance to PARP inhibition in prostate cancer through loss of function perturbations in the DNA pre-replication complex

Recent approvals of PARP inhibitors (PARPi) for BRCA-mutant metastatic castration resistant prostate cancer (mCRPC) necessitate an understanding of the factors that shape sensitivity and resistance. Reversion mutations that restore homologous recombination (HR) repair are detected in [~]50-80% of BRCA-mutant patients who respond but subsequently relapse, but there is currently little insight into why only [~]50% of BRCA-mutant patients display upfront resistance. To address this question, we performed a genome-wide CRISPR screen to identify genomic determinants of PARPi resistance in murine Brca2{Delta}/{Delta} prostate organoids genetically engineered in a manner that precludes the development of reversion mutations. Remarkably, we recovered multiple independent sgRNAs targeting three different members (Cdt1, Cdc6, Dbf4) of the DNA pre-replication complex (pre-RC), each of which independently conferred resistance to olaparib and the next generation PARP-1 selective inhibitor AZD5305. Moreover, sensitivity to PARP inhibition was restored in Brca2{Delta}/{Delta}, Cdc6-depleted prostate cells by knockdown of geminin, a negative regulator of Cdt1, further implicating the critical role of a functional pre-RC complex in PARPi sensitivity. Furthermore, [~]50% of CRPC tumors have copy number loss of pre-RC complex genes, particularly CDT1. Mechanistically, prostate cells with impaired pre-RC activity displayed rapid resolution of olaparib-induced DNA damage as well as protection from replication fork degradation caused by Brca2 loss, providing insight into how Brca2-mutant cancer cells can escape cell death from replication stress induced by PARP inhibition in the absence of HR repair. Of note, a pharmacologic inhibitor that targets the CDT1/geminin complex (AF615) restored sensitivity to AZD5305, providing a potential translational avenue to enhance sensitivity to PARP inhibition in BRCA-mutant cancers. SignificanceHere, we address a major limitation in the effectiveness of PARP inhibitors in BRCA-mutant prostate cancer treatment: only [~]50% of patients respond despite clear genomic evidence of defective homologous recombination. Prior efforts to study PARP inhibitor resistance in prostate cancer have been plagued by the lack of suitable cell lines. We overcame this challenge using primary prostate organoids coupled with genome-wide CRISPR screening. The key finding is that loss of function mutations in the DNA pre-replication complex confer PARP inhibitor resistance. These genes map to chromosomal regions frequently lost in prostate cancer and could therefore serve as potential biomarkers of treatment response. Pharmacologic inhibition of geminin, a negative regulator of the pre-replication complex, can restore PARP inhibitor sensitivity.

cancer biology↗

bioRxiv2024

Allocating Limited Surveillance Effort for Outbreak Detection of Endemic Foot and Mouth Disease

Foot and Mouth Disease (FMD) affects cloven-hoofed animals globally and has become a major economic burden for many countries around the world. Countries that have had recent FMD outbreaks are prohibited from exporting most meat products; this has major economic consequences for farmers in those countries, particularly farmers that experience outbreaks or are near outbreaks. Reducing the number of FMD outbreaks in countries where the disease is endemic is an important challenge that could drastically improve the livelihoods of millions of people. As a result, significant effort is expended on surveillance; but there is a concern that uninformative surveillance strategies may waste resources that could be better used on control management. Rapid detection through sentinel surveillance may be a useful tool to reduce the scale and burden of outbreaks. In this study, we use an extensive outbreak and cattle shipment network dataset from the Republic of Turkiye to test three possible strategies for sentinel surveillance allocation that differ in their data requirements: ranging from low to high data needs, we allocate limited surveillance to [1] farms that frequently send and receive shipments of animals (Network Connectivity), [2] farms near other farms with past outbreaks (Spatial Proximity) and [3] farms that receive many animals from other farms with past outbreaks (Network Proximity). We determine that all of these surveillance methods find a similar number of outbreaks - 2-4.5 times more outbreaks than were detected by surveying farms at random. On average across surveillance efforts, the Network Proximity and Network Connectivity methods each find a similar number of outbreaks and the Spatial Proximity method always finds the fewest outbreaks. Since the Network Proximity method does not outperform the other methods, these results indicate that incorporating both cattle shipment data and outbreak data provides only marginal benefit over the less data-intensive surveillance allocation methods for this objective. We also find that these methods all find more outbreaks when outbreaks are rare. This is encouraging, as early detection is critical for outbreak management. Overall, since the Spatial Proximity and Network Connectivity methods find a similar proportion of outbreaks, and are less data-intensive than the Network Proximity method, countries with endemic FMD whose resources are constrained could prioritize allocating sentinels based on whichever of those two methods requires less additional data collection.

ecology↗

bioRxiv2023

Designer small molecule control system based on Minocycline induced disruption of protein-protein interaction.

A versatile, safe, and effective small-molecule control system is highly desirable for clinical cell therapy applications. Therefore, we developed a two-component small-molecule control system based on the disruption of protein-protein interactions using minocycline, an FDA-approved antibiotic with wide availability, excellent bio-distribution, and low toxicity. The system comprises an anti-minocycline single-domain antibody (sdAb) and a minocycline-displaceable cyclic peptide. Here we show how this versatile system can be applied to OFF-switch split CAR systems (MinoCAR) and universal CAR adaptors (MinoUniCAR) with reversible, transient, and dose-dependent suppression; to a tunable T cell activation module based on MyD88/CD40 signaling; to a controllable cellular payload secretion system based on IL-12 KDEL retention and as a cell/cell inducible junction. This work represents an important step forward in the development of a remote-controlled system to precisely control the timing, intensity, and safety of therapeutic interventions. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=125 SRC="FIGDIR/small/553207v1_ufig1.gif" ALT="Figure 1"> View larger version (57K): org.highwire.dtl.DTLVardef@1a16d73org.highwire.dtl.DTLVardef@1189ceeorg.highwire.dtl.DTLVardef@e70a57org.highwire.dtl.DTLVardef@580fa9_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2023

Exploration of T-cell immune responses by expression of a dominant-negative SHP1 and SHP2

SHP1 and SHP2 are SH2 domain-containing proteins which have inhibitory phosphatase activity when recruited to phosphorylated ITIMs and ITSMs on inhibitory immune receptors. Consequently, SHP1 and SHP2 are key proteins in the transmission of inhibitory signals within T cells, constituting an important point of convergence for diverse inhibitory receptors. Therefore, SHP1 and SHP2 inhibition may represent a strategy for preventing immunosuppression of T cells mediated by cancers hence improving immunotherapies directed against these malignancies. Both SHP1 and SHP2 contain dual SH2 domains responsible for localization to the endodomain of inhibitory receptors and a protein tyrosine phosphatase domain which dephosphorylates and thus inhibits key mediators of T cell activation. We explored the interaction of the isolated SH2 domains of SHP1 and SHP2 to inhibitory motifs from PD1 and identified strong binding of both SH2 domains from SHP2 and more moderate binding in the case of SHP1. We next explored whether these a truncated form of SHP1/2 comprising only of SH2 domains (dSHP1/2) could act in a dominant negative fashion by preventing docking of the wild type proteins. When co-expressed with CARs we found that dSHP2 but not dSHP1 could alleviate immunosuppression mediated by PD1. We next explored the capacity of dSHP2 to bind with other inhibitory receptors and observed several potential interactions. In vivo we observed that the expression of PDL1 on tumor cells impaired the ability of CAR T cells to mediate tumor rejection and this effect was partially reversed by the co-expression of dSHP2 albeit at the cost of reduced CAR T cell proliferation. Modulation of SHP1 and SHP2 activity in engineered T cells through the expression of these truncated variants may enhance T cell activity and hence efficacy in the context of cancer immunotherapy.

immunology↗

bioRxiv2022

The amino acid transporter pfaat1 modulates chloroquine resistance and fitness in malaria parasites

Malaria parasites break down host hemoglobin into peptides and amino acids in the digestive vacuole for export to the parasite cytoplasm for growth: interrupting this process is central to the mode of action of several antimalarial drugs. Mutations in the chloroquine (CQ) resistance transporter, pfcrt, located in the digestive vacuole membrane, confer CQ resistance in Plasmodium falciparum, but typically affect parasite fitness. However, the role of other parasite loci in the evolution of CQ resistance is unclear. Here we use a combination of population genomics, genetic crosses and gene editing to demonstrate that a second vacuolar transporter plays a key role in both resistance and compensatory evolution. Longitudinal genomic analyses of the Gambian parasites revealed temporal signatures of selection on an amino acid transporter (pfaat1) S258L variant which increased from 0-87% in frequency between 1984 and 2014 in parallel with pfcrt1 K76T. Parasite genetic crosses then identified a chromosome 6 quantitative trait locus containing pfaat1 that is selected by CQ treatment. Gene editing demonstrated that pfaat1 S258L potentiates CQ-resistance but at a cost of reduced fitness, while pfaat1 F313S, a common Southeast Asian polymorphism, reduces CQ-resistance while restoring fitness. Our analyses reveal hidden complexity in CQ-resistance evolution, suggesting that pfaat1 may underlie regional differences in the dynamics of resistance evolution, and modulate parasite resistance or fitness by manipulating the balance between both amino acid and drug transport.

genomics↗

bioRxiv2021

Mutated neuronal voltage-gated CaV2.1 channels causing familial hemiplegic migraine 1 increase the susceptibility for cortical spreading depolarization and seizures and worsen outcome after experimental traumatic brain injury

Patients suffering from familial hemiplegic migraine type 1 (FHM1) may have a disproportionally severe outcome after head trauma, but the underlying mechanisms are unclear. Hence, we subjected knock-in mice carrying the severer S218L or milder R192Q FHM1 gain-of-function missense mutation in the CACNA1A gene that encodes the 1A subunit of neuronal voltage-gated CaV2.1 (P/Q-type) calcium channels and their wild-type (WT) littermates to experimental traumatic brain injury (TBI) by controlled cortical impact (CCI) and investigated cortical spreading depolarizations (CSDs), lesion volume, brain edema formation, and functional outcome. After TBI, all mutant mice displayed considerably more CSDs and seizures than WT mice, while S218L mutant mice had a substantially higher mortality. Brain edema formation and the resulting increase in intracranial pressure was more pronounced in mutant mice, while only S218L mutant mice had larger lesion volumes and worse functional outcome. Here we show that gain of CaV2.1 channel function worsens histopathological and functional outcome after TBI in mice. This phenotype was associated with a higher number of CSDs, increased seizure activity, and more pronounced brain edema formation. Hence, our results suggest increased susceptibility for CSDs and seizures as potential mechanisms for bad outcome after TBI in FHM1 mutation carriers.

neuroscience↗

bioRxiv2021

Influenza A (N1-N9) and Influenza B (B/Vic and B/Yam) Neuraminidase Pseudotypes as Tools for Pandemic Preparedness and Improved Influenza Vaccine design

To better understand how inhibition of the influenza neuraminidase (NA) protein contributes to protection against influenza, and to investigate its breadth and cross-neutralizing activity, we have produced lentiviral vectors pseudotyped with an avian H11 hemagglutinin (HA) and the NA (N1-N9) of all influenza A and (B/Victoria and B/Yamagata) influenza B subtypes. These NA viral pseudotypes (PV) possess stable NA activity and can be utilized as target antigens in in vitro assays to assess vaccine immunogenicity. Employing these NA PV, we have developed an enzyme-linked lectin assay (pELLA) for routine serology to measure neuraminidase inhibition (NI) titers of reference antisera, monoclonal antibodies, and post-vaccination sera with various influenza antigens. We have also shown that pELLA is more sensitive than the commercially available NA-Fluor in detecting NA inhibition in these samples. Our studies may lead to establishing the protective NA titer that contributes to NA-based immunity. This will aid in the design of superior, longer lasting, and more broadly protective vaccines that can be employed together with HA-targeted vaccines in a pre-pandemic approach.

immunology↗

bioRxiv2021

Nutrient limitation magnifies fitness costs of antimalarial drug resistance mutations

Drug resistance mutations tend to disrupt key physiological processes, and therefore carry a fitness cost. The size of these fitness costs is a central determinant of the rate of spread of these mutations in natural populations so are important to quantify. Head-to-head competition assays provide a standard approach to measuring differential fitness, and have been used extensively for malaria parasites. These assays typically use standardized culture media, containing RPMI 1640, which has a 1.4 to 5.5-fold (mean: 2.6-fold) higher concentration of amino acids than human blood. In this rich media we predict that fitness costs will be underestimated because resource competition is weak. We tested this prediction using an artemisinin sensitive parasite edited to contain kelch-C580Y or R561H mutations conferring resistance to artemisinin or synonymous control mutations. We examined the impact of these single amino acid mutations on fitness, using replicated head-to head competition experiments conducted in media containing (i) normal RPMI, (ii) modified RPMI with reduced amino acid concentration, (iii) RPMI containing only isoleucine, or (iv) 3-fold diluted RPMI. We found a significant 1.3 to 1.4-fold increase in fitness costs measured in modified and isoleucine-only media relative to normal media, while fitness costs were 2.5-fold higher in diluted media. We conclude that fitness costs are strongly affected by media composition and will be significantly underestimated in normal RPMI. Elevated fitness costs in nature will limit spread of ART-resistance but will also promote evolution of compensatory mutations that restore fitness, and can be exploited to maximize selection in laboratory experiments.

microbiology↗

bioRxiv2021

Establishment of pan-Influenza A (H1-H18) and pan-Influenza B (pre-split, Vic/Yam) Pseudotype Libraries for efficient vaccine antigen selection

We have developed an influenza hemagglutinin (HA) pseudotype library encompassing Influenza A subtypes HA1-18, and Influenza B subtypes (both lineages) to be employed in influenza pseudotype microneutralization (pMN) assays. The pMN is highly sensitive and specific for detecting virus-specific neutralizing antibodies against influenza viruses and can be used to assess antibody functionality in vitro. Here we show the production of these viral HA pseudotypes and their employment as substitutes for wildtype viruses in influenza serological and neutralization assays. We demonstrate its utility in detecting serum response to vaccination with the ability to evaluate cross-subtype neutralizing responses elicited by specific vaccinating antigens. Our findings may inform further pre-clinical studies involving immunization dosing regimens in mice and may help in the creation and selection of better antigens for vaccine design. These HA pseudotypes can be harnessed to meet strategic objectives that contribute to the strengthening of global influenza surveillance, expansion of seasonal influenza prevention and control policies, and strengthening pandemic preparedness and response.

immunology↗

bioRxiv2021

Characterisation of a novel ACE2-based therapeutic with enhanced rather than reduced activity against SARS-CoV2 variants

The human angiotensin-converting enzyme 2 acts as the host cell receptor for SARS-CoV-2 and the other members of the Coronaviridae family SARS-CoV-1 and HCoV-NL63. Here we report the biophysical properties of the SARS-CoV-2 spike variants D614G, B.1.1.7 and B.1.351 with affinities to the ACE2 receptor and infectivity capacity, revealing weaknesses in the developed neutralising antibody approaches. Furthermore, we report a pre-clinical characterisation package for a soluble receptor decoy engineered to be catalytically inactive and immunologically inert, with broad neutralisation capacity, that represents an attractive therapeutic alternative in light of the mutational landscape of COVID-19. This construct efficiently neutralised four SARS-CoV-2 variants of concern. The decoy also displays antibody-like biophysical properties and manufacturability, strengthening its suitability as a first-line treatment option in prophylaxis or therapeutic regimens for COVID-19 and related viral infections.

immunology↗

bioRxiv2020

Preventive efficacy of a tenofovir alafenamide fumarate nanofluidic implant in SHIV-challenged nonhuman primates

Pre-exposure prophylaxis (PrEP) using antiretroviral oral drugs is effective at preventing HIV transmission when individuals adhere to the dosing regimen. Tenofovir alafenamide (TAF) is a potent antiretroviral drug, with numerous long-acting (LA) delivery systems under development to improve PrEP adherence. However, none has undergone preventive efficacy assessment. Here we show that LA TAF using a novel subcutaneous nanofluidic implant (nTAF) confers partial protection from HIV transmission. We demonstrate that sustained subcutaneous delivery through nTAF in rhesus macaques maintained tenofovir diphosphate concentration at a median of 390.00 fmol/106 peripheral blood mononuclear cells, 9 times above clinically protective levels. In a non-blinded, placebo-controlled rhesus macaque study with repeated low-dose rectal SHIVSF162P3 challenge, the nTAF cohort had a 62.50% reduction (95% CI: 1.72% to 85.69%; p=0.068) in risk of infection per exposure compared to the control. Our finding mirrors that of tenofovir disoproxil fumarate (TDF) monotherapy, where 60.00% protective efficacy was observed in macaques, and clinically, 67.00% reduction in risk with 86.00% preventive efficacy in individuals with detectable drug in the plasma. Overall, our nanofluidic technology shows potential as a subcutaneous delivery platform for long-term PrEP and provides insights for clinical implementation of LA TAF for HIV prevention.

bioengineering↗

bioRxiv2019

Rad9/53BP1 promotes crossover recombination DNA repair by limiting the Sgs1 and Mph1 helicases

A DNA double strand break (DSB) is primed for homologous recombination (HR) repair through the nucleolytic processing (resection) of its ends, leading to the formation of a 3' single-stranded DNA (ssDNA). Generation of the ssDNA is accompanied by the loading of several repair factors, including the ssDNA binding factor RPA and the recombinase Rad51. Then, depending upon the availability and location of a homologous sequence, different types of HR mechanisms can occur. Inefficient or slow HR repair results in the activation of the DNA damage checkpoint (DDC)1. In budding yeast, the 53BP1 ortholog Rad9 acts as a scaffold, mediating signal from upstream kinases Mec1 and Tel1 (ATR and ATM in human) to downstream effectors kinases Rad53 and Chk1 (CHK2 and CHK1 in human). In addition to its role in DDC, Rad9 limits DSB resection 2. Remarkably, this function is conserved in 53BP1, also being implicated in cancer biology in human cells 3,4.\n\nHere we show that Rad9 limits the recruitment of the helicases Sgs1 and Mph1 on to a DSB, promoting Rad51-dependent recombination with long track DNA conversions, crossovers and break-induced replication (BIR). This regulation couples the DDC with the choice and effectiveness of HR sub-pathways, and might be critical to limit genome instability with implication for cancer research.

molecular biology↗

bioRxiv2017

Unintended Consequences and the Paradox of Control: Management of Emerging Pathogens with Age-Specific Virulence

We project the long term incidence of Zika virus disease (ZVD) under varying hazards of infection and consider how the age-distribution of disease burden varies between these scenarios. Pathogens with age-structured disease outcomes, such as rubella and Zika virus, require that management decisions consider their impact not only on total disease incidence but also on distribution of disease burden within a population. In some cases, reductions of overall transmission can have the paradoxical effect of increasing the incidence of severe disease despite decreasing the total incidence. This happens because of corresponding increases in the average age of infection. Beginning with the current population structure and demographic rates of Brazil, we project forward total ZVD burden as measured by cases occurring in pregnant women and document the scenarios under which a paradox of control for Zika management emerges. We conclude that while a paradox of control can occur for ZVD, the higher total costs from increasing the average age of infection will only be realized after several decades and vanish under conservative discounting of future costs. This indicates that managers faced with an emerging pathogen should prioritize current disease incidence over potential increases in severe disease outcomes in the endemic state.\n\nAuthor SummaryThe intuitive response to an emerging outbreak is to halt, or at least reduce, transmission. However, in some circumstances, reducing overall transmission and incidence may be counterproductive from a public health perspective as public health interventions affect both the total level and the distribution of disease burden. We consider the scenarios under which reducing transmission of an emerging pathogen such as Zika virus may increase the costs associated with disease in the most vulnerable segments of the population - in this case, reproductive-age women. We conclude that after applying standard discounting rates to future cases, the \"paradox of control\" vanishes and reducing hazard of infection uniformly reduces the total costs associated with severe disease.

epidemiology↗