Primary Human Foreskin Fibroblasts Research Articles

Sample Preparation for Global Metabolic Profiling of Vaccinia Virus-Infected Primary Human Foreskin Fibroblasts.

Vaccinia virus (VACV), the prototype member of the Poxviridae family, has played a crucial role in medicine as a key component in the development of smallpox vaccines, contributing to the eradication of this deadly disease. Beyond its historical significance, VACV continues to be pivotal in researching metabolic alterations induced by viral infections. Studies have revealed that VACV can impact pathways such as glycolysis, the tricarboxylic acid (TCA) cycle, and lipid metabolism in host cells, offering valuable insights into host-virus interactions and broader cellular metabolism. The preference for primary cells, such as human foreskin fibroblasts (HFFs), over cancer cells in metabolic studies is justified for their physiological relevance, representing native cell types with genetic stability. Metabolic profiling is an ideal tool for studying virus-induced metabolic alterations, providing a comprehensive analysis of changes in cellular metabolism triggered by viral infections. This chapter outlines a protocol for extracting HFFs, culturing, infecting them with VACV, and conducting untargeted global metabolic profiling to elucidate detailed metabolic statuses of the infected cells. This protocol may be modified for understanding the intricacies of host-virus interactions at the metabolic interface for other poxviruses and non-poxviruses.

Stimulation of neutral lipid synthesis via viral growth factor signaling and ATP citrate lyase during vaccinia virus infection.

Fatty acid metabolism can provide various products essential for viral infections. How vaccinia virus (VACV), the prototype of poxviruses, modulates fatty acid metabolism is not well understood. Here, we show that VACV infection results in increased neutral lipid droplet synthesis, the organelles that play a crucial role in storing and mobilizing fatty acids for energy production via β-oxidation. Citrate is the first tricarboxylic acid (TCA) cycle intermediate that can be transported to the cytosol to be converted to acetyl-CoA for de novo fatty acid biosynthesis. We found that VACV infection stimulates the S455 phosphorylation of ATP citrate lyase (ACLY), a pivotal enzyme that links citrate metabolism with lipid metabolism. We demonstrate that the inhibition of neutral lipid droplet synthesis and ACLY severely suppresses VACV replication. Remarkably, we found that virus growth factor (VGF)-induced signaling is essential for the VACV-mediated upregulation of ACLY phosphorylation and neutral lipid droplets. Finally, we report that VGF-induced EGFR-Akt pathway and ACLY phosphorylation are important for VACV stimulation of neutral lipid synthesis. These findings identified a new way of rewiring cell metabolism by a virus and a novel function for VGF in the governance of virus-host interactions through the induction of a key enzyme at the crossroads of the TCA cycle and fatty acid metabolism. Our study also provides a mechanism for the role played by VGF and its downstream signaling cascades in the modulation of lipid metabolism in VACV-infected cells.IMPORTANCENeutral lipid droplets are vital players in cellular metabolism. Here, we showed that VACV induces neutral lipid droplet synthesis in infected primary human foreskin fibroblasts and identified the cellular and viral factors needed. We identified VACV encoded growth factor (VGF) as an essential viral factor that induces cellular EGFR-Akt signaling to increase lipid droplets. Interestingly, VACV increases the S455 phosphorylation of ACLY, a key metabolic enzyme that sits at the crossroads of carbohydrate and lipid metabolism in a VGF-EGFR-Akt-dependent manner. We also found that ACLY is vital for VACV-induced lipid droplet synthesis. Our findings identified the modulation of ACLY by a virus and identified it as a potential target for antiviral development against pathogenic poxviruses. Our study also expands the role of growth factor signaling in boosting VACV replication by targeting fatty acid metabolism.

Degradable Cell-Adhesive Hybrid Hydrogels by Cross-Linking of Gelatin with Poly(2-isopropenyl-2-oxazoline).

This study focused on the cross-linking of poly(2-isopropenyl-2-oxazoline) (PiPOx) with gelatin to obtain strong, degradable hybrid hydrogels with good cell adhesion. The molecular weight and concentration of PiPOx and the PiPOx-to-gelatin ratio were varied to adjust the mechanical and swelling properties of the hybrid hydrogels. The swelling degree of PiPOx-gelatin hydrogels in water ranged between 1260 and 810%, with the corresponding Young's compressive moduli ranging from 77 to 215 kPa. Rheological measurements demonstrated the mechanical stability of the hydrogels. The hydrogels exhibited substantial degradation in Dulbecco's phosphate-buffered saline (DPBS) and cell culture medium within several weeks, indicating their degradability and responsiveness. The cell adhesion assay with primary human foreskin fibroblasts revealed the hybrid hydrogels are noncytotoxic and support cell attachment and proliferation. These strong hydrogels thus show excellent potential as biomedical cell scaffolds, combining the tunability and strength of PiPOx hydrogels with gelatin's cell-interactive properties while the ester-containing cross-links provide tunable degradability.

Solid-State Crosslinkable, Shape-Memory Polyesters Serving Tissue Engineering.

Acrylate-endcapped urethane-based precursors constituting a poly(D,L-lactide)/poly(ε-caprolactone) (PDLLA/PCL) random copolymer backbone aresynthesized with linear and star-shaped architectures and various molar masses. It isshown that the glass transition and thus the actuation temperature couldbe tuned by varying the monomer content (0-8 wt% ε-caprolactone, Tg,crosslinked = 10-42 °C) in the polymers. The resulting polymers areanalyzed for their physico-chemical properties and viscoelastic behavior (G'max = 9.6-750kPa). The obtained polymers aresubsequently crosslinked and their shape-memory properties arefound to be excellent (Rr = 88-100%, Rf = 78-99.5%). Moreover, their potential toward processing via various additive manufacturing techniques (digital light processing, two-photon polymerization and direct powder extrusion) isevidenced with retention of their shape-memory effect. Additionally, all polymers arefound to be biocompatible in direct contact in vitrocell assays using primary human foreskin fibroblasts (HFFs) through MTS assay (up to ≈100% metabolic activity relative to TCP) and live/dead staining (>70% viability).

Dual inhibition of innate immunity and apoptosis by human cytomegalovirus protein UL37x1 enables efficient virus replication.

Immune evasion and inhibition of apoptosis are required for successful virus infection. However, inhibition of apoptosis can increase antiviral immune responses, which can then clear viral infections. Here we show that human cytomegalovirus (HCMV)-encoded UL37 exon-1 protein (UL37x1) not only inhibits apoptosis but also suppresses the cGAS-STING immune pathway. Using co-immunoprecipitation assays, we found that UL37x1 binds to TBK1 to abrogate the TBK1-STING-IRF3 interaction. Although the anti-apoptosis function of UL37x1 increases immune signalling, the immunosuppressive role of UL37x1 counteracts this undesirable side-effect. Furthermore, we used mutational analyses to show that the loss of either immunosuppressive or anti-apoptotic function of UL37x1 significantly reduced HCMV replication in human primary foreskin fibroblasts and humanized mice by over twofold. Finally, loss of both functions resulted in over fourfold reduction of HCMV replication in the same cell type and mouse model, showing that both UL37x1 functions are crucial for HCMV infection. We conclude that this sophisticated mechanism enables HCMV to control innate immunity and apoptosis to ensure efficient infection.

Human Cytomegalovirus Infection Elicits Global Changes in Host Transcription by RNA Polymerases I, II, and III.

How human cytomegalovirus (HCMV) infection impacts the transcription of the host genome remains incompletely understood. Here, we examine the global consequences of infection of primary human foreskin fibroblasts (HFFs) on transcription by RNA polymerase I, II, and III over the course of a lytic infection using PRO-Seq. The expected rapid induction of innate immune response genes is observed with specific subsets of genes exhibiting dissimilar expression kinetics. We find minimal effects on Pol II initiation, but increased rates of the release of paused Pol II into productive elongation are detected by 24 h postinfection and pronounced at late times postinfection. Pol I transcription increases during infection and we provide evidence for a potential Pol I elongation control mechanism. Pol III transcription of tRNA genes is dramatically altered, with many induced and some repressed. All effects are partially dependent on viral genome replication, suggesting a link to viral mRNA levels and/or a viral early–late or late gene product. Changes in tRNA transcription are connected to distinct alterations in the chromatin state around tRNA genes, which were probed with high-resolution DFF-ChIP. Additionally, evidence is provided that the Pol III PIC stably contacts an upstream −1 nucleosome. Finally, we compared and contrasted our HCMV data with results from published experiments with HSV-1, EBV, KSHV, and MHV68. We report disparate effects on Pol II transcription and potentially similar effects on Pol III transcription.

Hyperglycemia attenuates fibroblast contractility via suppression of TβRII receptor modulated α-smooth muscle actin expression

Nonhealing wounds are a common complication in patients suffering from diabetes with hyperglycemia being the most deteriorating factor for this serious pathological condition. Despite the great body of data, the molecular mechanisms by which high glucose affects cellular physiology are still poorly defined. Here we used primary human foreskin fibroblasts cultured in normo- and hyperglycemic conditions to study the mechanisms leading to altered cell contractility. Our results demonstrated that 25 mmol/L glucose effectively reduced fibroblasts ability to contract fibrin gels, and this physiological change was accompanied by a decrease in alpha-smooth muscle actin expression and the percentage of spontaneously differentiated myofibroblasts in the population of high glucose-treated fibroblasts. These changes were a result of hyperglycemia-induced attenuation of TGF-β1 signaling, involving specific suppression of TGF-β receptor type II but not type I expression. Decreased production of the receptor abolished the ability of exogenously added TGF-β1 to induce Smad2/3 phosphorylation in the presence of high glucose concentrations. Our results identify TGF-β receptor type II as hyperglycemia expression-sensitive receptor and add further aspect to the complex way in which high glucose can affect the wound healing process.

LATE–a novel sensitive cell-based assay for the study of CRISPR/Cas9-related long-term adverse treatment effects

Since the introduction of clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9), genome editing has been broadly applied in basic research and applied biotechnology, whereas translation into clinical testing has raised safety concerns. Indeed, although frequencies and locations of off-target events have been widely addressed, little is known about their potential biological consequences in large-scale long-term settings. We have developed a long-term adverse treatment effect (LATE) in vitro assay that addresses potential toxicity of designer nucleases by assessing cell transformation events. In small-scale proof-of-principle experiments we reproducibly detected low-frequency (<0.5%) growth-promoting events in primary human newborn foreskin fibroblasts (NUFF cells) resulting from off-target cleavage in the TP53 gene. Importantly, the LATE assay detected not only off-target effects in TP53 not predicted by popular online tools but also growth-promoting mutations in other tumor suppressor genes, such as p21 and PLZF. It convincingly verified strongly reduced off-target activities of high fidelity compared with first-generation Cas9. Finally, the LATE assay was readily adapted to other cell types, namely clinically relevant human mesenchymal stromal cells (hMSCs) and retinal pigmented epithelial (RPE-1) cells. In conclusion, the LATE assay allows assessment of physiological adverse effects of the CRISPR/Cas system and might therefore be useful for preclinical safety studies.

Using Human Primary Foreskin Fibroblasts to Study Cellular Damage and Mitochondrial Dysfunction.

Several cell lines of different origin are routinely used in research and drug development as important models to study human health and disease. Studying cells in culture represents an easy and convenient tool to approach complex biological questions, but the disadvantage is that they may not necessarily reflect what is effectively occurring in vivo. Human primary cells can help address this limitation, as they are isolated directly from human biological samples and can preserve the morphological and functional features of their tissue of origin. In addition, these can offer more relevant data and better solutions to investigators because they are not genetically manipulated. Human foreskin tissue discarded after surgery, for instance, represents a precious source for isolating such cells, including human foreskin fibroblasts (FSK), which are used in several areas of research and medicine. The overall health of cells is determined by the mitochondria. Alterations of cellular metabolism and cell death pathways depend, in part, on the number, size, distribution, and structure of mitochondria, and these can change under different cellular and pathological conditions. This highlights the need to develop accurate approaches to study mitochondria and evaluate their function. Here, we describe three easy, step‐by‐step protocols to study cellular viability and mitochondrial functionality in FSK. We describe how to use circumcision tissue obtained from the clinic to isolate FSK cells by mechanical and enzymatic disaggregation, how to use a cationic dye, crystal violet, which is retained by proliferating cells, to determine cell viability, and how to prepare samples to assess the metabolic status of cells by evaluating different mitochondrial parameters with transmission electron microscopy. We have successfully used the approaches outlined here to recapitulate physiological conditions in these cells in order to study the effects of increased intracellular levels of formaldehyde. © 2020 U.S. Government. Basic Protocol 1: Isolation and maintenance of human primary foreskin fibroblasts (FSK) Basic Protocol 2: Determination of cell viability by crystal violet staining Basic Protocol 3: Transmission electron microscopy to study cellular damage and mitochondrial dysfunction

Abstract 2538: p53 activation induces cell cycle arrest by promoting DREAM and RB repression of cell cycle genes

Abstract p53 activation results cell cycle arrest at the G1/S checkpoint and the repression of early (G1/S) and late (G2/M) cell cycle gene expression in a p21 dependent manner. The mechanism how p53 and p21 repress cell cycle gene expression is unclear. p21 is known to repress CDK2 which is a key inhibitor of the pocket protein family members RB and p130. During a normal cell cycle, p130 as part of the DREAM complex (DP1, RB-like p130, E2F4, and MuvB) and RB cooperate to repress expression of early (G1/S) and late (G2/M) cell cycle gene expression. DREAM binds and represses late (G2/M) cell cycle promoters through MuvB binding and early (G1/S) cell cycle promoters though repressor E2F binding. RB is only able to bind and repress early (G1/S) cell cycle promoters through its interaction with activator E2Fs. The requirement for DREAM and RB for control of cell cycle gene expression after p53 activation was unknown. We hypothesized that DREAM and RB would cooperate to repress cell cycle gene expression after DNA damage. Using primary human foreskin fibroblast cells lacking RB and/or p130, we found repression of early and late cell cycle gene expression is differentially regulated after p53 activation. We found that while RB is required for repression of early (G1/S) cell cycle genes after p53 activation, DREAM is required for repression of expression of late (G2/M) cell cycle genes. Surprisingly, DREAM was unable to repress early cell cycle genes after p53 activation, suggesting that RB is the key regulator of G1/S gene expression during cellular stress like DNA damage. Further, the requirement for DREAM to repress late cell cycle gene expression underlies the importance of DREAM to prevent expression of mitosis inducing genes in a state like DNA damage when mitosis could result in propagation of mutated DNA. We found that p107, a protein reported be able to replace p130 in DREAM, does not potently repress early cell cycle genes in HFFs under contact arrest and serum starvation. However, we found that p107 strongly represses expression of late cell cycle genes during G0 in cells lacking p130 alone or in combination with RB. These data provide evidence for a specific role for p107-DREAM not previously appreciated. Together, our data show that control of cell cycle gene expression after p53 activation is split in two: RB represses early cell cycle genes while DREAM represses late cell cycle genes. Citation Format: Amy E. Schade, Martin Fischer, James A. DeCaprio. p53 activation induces cell cycle arrest by promoting DREAM and RB repression of cell cycle genes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2538.

The Susceptibility of Primary Dermis Fibroblasts from the Chinese Tree Shrew to Human Cytomegalovirus Infection.

As a universal pathogen leading to neonatal defects and transplant failure, human cytomegalovirus (HCMV) has strict species specificity and this has prevented the development of a suitable animal model for the pathogenesis study. The mechanism of cross-species barrier remains elusive and there are so far no non-human cell culture models that support HCMV replication. The Chinese tree shrew (Tupaia belangeri chinensis) is a small laboratory animal and evolutionary closely related with primates. We investigated the susceptibility of primary tree shrew dermis fibroblasts (TSDF) to HCMV infection. Infection with a GFP-expressing HCMV virus resulted in green fluorescence in infected cells with the expression of IE1, UL44 and pp28. The titers of cell-free viruses reached 103 PFU/mL at 96 hpi, compared to titers of 104 PFU/mL observed in primary human foreskin fibroblasts. Our results suggested that TSDF was semi-permissive for HCMV infection. The TSDF model could be further used to investigate key factors influencing cross-species multiplication of HCMV.

The Effect of Ethanol on Telomere Dynamics and Regulation in Human Cells.

Telomeres (TLs) protect chromosome ends from chromosomal fusion and degradation, thus conferring genomic stability, and play crucial roles in cellular aging and disease. Recent studies have found a correlation between environmental, physiological and even mental stresses on TL dynamics in humans. However, the causal relationship between stress and TL length and the molecular mechanisms underlying that relationship are far from being understood. This study describes the effect of moderate concentrations of ethanol, equivalent to social drinking, on human TL dynamics and partially elucidates the mechanism mediating this effect. The exposure of Immortalized human foreskin fibroblast, primary human foreskin fibroblast and human hepatocellular carcinoma cells to 25 mM ethanol for one week moderately shortened telomeres in all cells. Similar TL shortening was obtained following cells’ exposure to 25 µM acetaldehyde (AcH) and to a much lower extent after exposure to 4-methylpyrazolean, an inhibitor of alcoholdehydrogenase, suggesting that AcH plays a key role in ethanol-dependent telomere shortening. Telomerase activity was not involved in this effect. TRF2 and several TRF2 binding proteins increased their binding to TLs after ethanol treatment, implying their involvement in this effect. The methylation status of several sub-telomeric regions increased in response to EtOH exposure. Gene expression profiling showed distinct patterns in cells treated with EtOH and in cells recovered from EtOH. In addition to cellular ageing, the described telomere shortening may contribute to the carcinogenic potential of acute alcohol consumption; both are associated with the shortening of TLs and provide new insights regarding the moderate consumption of alcohol referred to as “social drinking.”

A standardized approach to the evaluation of antivirals against DNA viruses: Orthopox-, adeno-, and herpesviruses

The search for new compounds with a broad spectrum of antiviral activity is important and requires the evaluation of many compounds against several distinct viruses. Researchers attempting to develop new antiviral therapies for DNA virus infections currently use a variety of cell lines, assay conditions and measurement methods to determine in vitro drug efficacy, making it difficult to compare results from within the same laboratory as well as between laboratories. In this paper we describe a common assay platform designed to facilitate the parallel evaluation of antiviral activity against herpes simplex virus type 1, herpes simplex virus type 2, varicella-zoster virus, cytomegalovirus, vaccinia virus, cowpox virus, and adenovirus. The automated assays utilize monolayers of primary human foreskin fibroblast cells in 384-well plates as a common cell substrate and cytopathic effects and cytotoxicity are quantified with CellTiter-Glo. Data presented demonstrate that each of the assays is highly robust and yields data that are comparable to those from other traditional assays, such as plaque reduction assays. The assays proved to be both accurate and robust and afford an in depth assessment of antiviral activity against the diverse class of viruses with very small quantities of test compounds. In an accompanying paper, we present a standardized approach to evaluating antivirals against lymphotropic herpesviruses and polyomaviruses and together these studies revealed new activities for reference compounds. This approach has the potential to accelerate the development of broad spectrum therapies for the DNA viruses.

Strategy of Human Cytomegalovirus To Escape Interferon Beta-Induced APOBEC3G Editing Activity.

The apolipoprotein B editing enzyme catalytic subunit 3 (APOBEC3) is a family of DNA cytosine deaminases that mutate and inactivate viral genomes by single-strand DNA editing, thus providing an innate immune response against a wide range of DNA and RNA viruses. In particular, APOBEC3A (A3A), a member of the APOBEC3 family, is induced by human cytomegalovirus (HCMV) in decidual tissues where it efficiently restricts HCMV replication, thereby acting as an intrinsic innate immune effector at the maternal-fetal interface. However, the widespread incidence of congenital HCMV infection implies that HCMV has evolved to counteract APOBEC3-induced mutagenesis through mechanisms that still remain to be fully established. Here, we have assessed gene expression and deaminase activity of various APOBEC3 gene family members in HCMV-infected primary human foreskin fibroblasts (HFFs). Specifically, we show that APOBEC3G (A3G) gene products and, to a lesser degree, those of A3F but not of A3A, are upregulated in HCMV-infected HFFs. We also show that HCMV-mediated induction of A3G expression is mediated by interferon beta (IFN-β), which is produced early during HCMV infection. However, knockout or overexpression of A3G does not affect HCMV replication, indicating that A3G is not a restriction factor for HCMV. Finally, through a bioinformatics approach, we show that HCMV has evolved mutational robustness against IFN-β by limiting the presence of A3G hot spots in essential open reading frames (ORFs) of its genome. Overall, our findings uncover a novel immune evasion strategy by HCMV with profound implications for HCMV infections.IMPORTANCE APOBEC3 family of proteins plays a pivotal role in intrinsic immunity defense mechanisms against multiple viral infections, including retroviruses, through the deamination activity. However, the currently available data on APOBEC3 editing mechanisms upon HCMV infection remain unclear. In the present study, we show that particularly the APOBEC3G (A3G) member of the deaminase family is strongly induced upon infection with HCMV in fibroblasts and that its upregulation is mediated by IFN-β. Furthermore, we were able to demonstrate that neither A3G knockout nor A3G overexpression appears to modulate HCMV replication, indicating that A3G does not inhibit HCMV replication. This may be explained by HCMV escape strategy from A3G activity through depletion of the preferred nucleotide motifs (hot spots) from its genome. The results may shed light on antiviral potential of APOBEC3 activity during HCMV infection, as well as the viral counteracting mechanisms under A3G-mediated selective pressure.

Keton cisimlerinin insan meme kanseri hücrelerinde (MCF-7) canlılık üzerine etkileri

Objective: Cancer cells exhibit an elevated glycolytic phenotypeunder aerobic conditions, which is known as the Warburg effect.Recent studies have also shown that cancer cells are glucosedependentand cannot use ketone bodies as a primary source ofenergy. In this study, we have investigated the effects of ketonebodies on viability of breast cancer cells considering that breastcancer cells would not use ketone bodies as a primary energysource.Materials and Methods: In this study we have used MCF-7cells, which are breast cancer cells that cannot use ketone bodiesas a primary energy source and human foreskin fibroblast cells(HFF) as controls. We measured cell viability in both cells culturedin the presence or absence of glucose as well as the ketone bodiesacetoacetate and beta-hydroxybutyrate.Results: Cell viability was significantly decreased in responseto ketone bodies compared with control media in MCF-7 cellswhereas in control cells (HFF) cell viability was not changed.Conclusion: In light of the data obtained, we suggest thatdietary manipulation with the use of ketone bodies may be a newtherapeutic strategy for breast cancer.

Mechanisms of Host IFI16, PML, and Daxx Protein Restriction of Herpes Simplex Virus 1 Replication.

The initial events after DNA virus infection involve a race between epigenetic silencing of the incoming viral DNA by host cell factors and expression of viral genes. Several host gene products, including the nuclear domain 10 (ND10) components PML (promyelocytic leukemia) and Daxx (death domain-associated protein 6), as well as IFI16 (interferon-inducible protein 16), have been shown to restrict herpes simplex virus 1 (HSV-1) replication. Whether IFI16 and ND10 components work together or separately to restrict HSV-1 replication is not known. To determine the combinatorial effects of IFI16 and ND10 proteins on viral infection, we depleted Daxx or PML in primary human foreskin fibroblasts (HFFs) in the presence or absence of IFI16. Daxx or IFI16 depletion resulted in higher ICP0 mutant viral yields, and the effects were additive. Surprisingly, small interfering RNA (siRNA) depletion of PML in the HFF cells led to decreased ICP0-null virus replication, while short hairpin RNA (shRNA) depletion led to increased ICP0-null virus replication, arguing that different PML isoforms or PML-related proteins may have restrictive or proviral functions. In normal human cells, viral DNA replication increases expression of all classes of HSV-1 genes. We observed that IFI16 repressed transcription from both parental and progeny DNA genomes. Taken together, our results show that the mechanisms of action of IFI16 and ND10 proteins are independent, at least in part, and that IFI16 exerts restrictive effects on both input and replicated viral genomes. These results raise the potential for distinct mechanisms of action of IFI16 on parental and progeny viral DNA molecules.IMPORTANCE Many human DNA viruses transcribe their genomes and replicate in the nucleus of a host cell, where they exploit the host cell nuclear machinery for their own replication. Host factors attempt to restrict viral replication by blocking such events, and viruses have evolved mechanisms to neutralize the host restriction factors. In this study, we provide information about the mechanisms of action of three host cell factors that restrict replication of herpes simplex virus (HSV). We found that these factors function independently and that one acts to restrict viral transcription from parental and progeny viral DNA genomes. These results provide new information about how cells counter DNA virus replication in the nucleus and provide possible approaches to enhance the ability of human cells to resist HSV infection.

Human Cytomegalovirus Tegument Protein pp65 (pUL83) Dampens Type I Interferon Production by Inactivating the DNA Sensor cGAS without Affecting STING.

The innate immune response plays a pivotal role during human cytomegalovirus (HCMV) primary infection. Indeed, HCMV infection of primary fibroblasts rapidly triggers strong induction of type I interferons (IFN-I), accompanied by proinflammatory cytokine release. Here, we show that primary human foreskin fibroblasts (HFFs) infected with a mutant HCMV TB40/E strain unable to express UL83-encoded pp65 (v65Stop) produce significantly higher IFN-β levels than HFFs infected with the wild-type TB40/E strain or the pp65 revertant (v65Rev), suggesting that the tegument protein pp65 may dampen IFN-β production. To clarify the mechanisms through which pp65 inhibits IFN-β production, we analyzed the activation of the cGAS/STING/IRF3 axis in HFFs infected with either the wild type, the revertant v65Rev, or the pp65-deficient mutant v65Stop. We found that pp65 selectively binds to cGAS and prevents its interaction with STING, thus inactivating the signaling pathway through the cGAS/STING/IRF3 axis. Consistently, addition of exogenous cGAMP to v65Rev-infected cells triggered the production of IFN-β levels similar to those observed with v65Stop-infected cells, confirming that pp65 inactivation of IFN-β production occurs at the cGAS level. Notably, within the first 24 h of HCMV infection, STING undergoes proteasome degradation independently of the presence or absence of pp65. Collectively, our data provide mechanistic insights into the interplay between HCMV pp65 and cGAS, leading to subsequent immune evasion by this prominent DNA virus.IMPORTANCE Primary human foreskin fibroblasts (HFFs) produce type I IFN (IFN-I) when infected with HCMV. However, we observed significantly higher IFN-β levels when HFFs were infected with HCMV that was unable to express UL83-encoded pp65 (v65Stop), suggesting that pp65 (pUL83) may constitute a viral evasion factor. This study demonstrates that the HCMV tegument protein pp65 inhibits IFN-β production by binding and inactivating cGAS early during infection. In addition, this inhibitory activity specifically targets cGAS, since it can be bypassed via the addition of exogenous cGAMP, even in the presence of pp65. Notably, STING proteasome-mediated degradation was observed in both the presence and absence of pp65. Collectively, our data underscore the important role of the tegument protein pp65 as a critical molecular hub in HCMV's evasion strategy against the innate immune response.

Highly selective and sensitive macrocycle-based dinuclear foldamer for fluorometric and colorimetric sensing of citrate in water

The selective detection of citrate anions is essential for various biological functions in living systems. A quantitative assessment of citrate is required for the diagnosis of various diseases in the human body; however, it is extremely challenging to develop efficient fluorescence and color-detecting molecular probes for sensing citrate in water. Herein, we report a macrocycle-based dinuclear foldamer (1) assembled with eosin Y (EY) that has been studied for anion binding by fluorescence and colorimetric techniques in water at neutral pH. Results from the fluorescence titrations reveal that the 1·EY ensemble strongly binds citrate anions, showing remarkable selectivity over a wide range of inorganic and carboxylate anions. The addition of citrate anions to the 1·EY adduct led to a large fluorescence enhancement, displaying a detectable color change under both visible and UV light in water up to 2 μmol. The biocompatibility of 1·EY as an intracellular carrier in a biological system was evaluated on primary human foreskin fibroblast (HF) cells, showing an excellent cell viability. The strong binding properties of the ensemble allow it to be used as a highly sensitive, detective probe for biologically relevant citrate anions in various applications.

Immunoprecipitation of Tri-methylated Capped RNA.

Cellular quiescence (also known as G0 arrest) is characterized by reduced DNA replication, increased autophagy, and increased expression of cyclin-dependent kinase p27Kip1. Quiescence is essential for wound healing, organ regeneration, and preventing neoplasia. Previous findings indicate that microRNAs (miRNAs) play an important role in regulating cellular quiescence. Our recent publication demonstrated the existence of an alternative miRNA biogenesis pathway in primary human foreskin fibroblast (HFF) cells during quiescence. Indeed, we have identified a group of pri-miRNAs (whose mature miRNAs were found induced during quiescence) modified with a 2,2,7-trimethylguanosine (TMG)-cap by the trimethylguanosine synthase 1 (TGS1) protein and transported to the cytoplasm by the Exportin-1 (XPO1) protein. We used an antibody against (TMG)-caps (which does not cross-react with the (m7G)-caps that most pri-miRNAs or mRNAs contain [Luhrmann et al., 1982]) to perform RNA immunoprecipitations from total RNA extracts of proliferating or quiescent HFFs. The novelty of this assay is the specific isolation of pri-miRNAs as well as other non-coding RNAs containing a TMG-cap modification.

Anion Complexation Studies of 3-Nitrophenyl-Substituted Tripodal Thiourea Receptor: A Naked-Eye Detection of Sulfate via Fluoride Displacement Assay.

A thiourea-based tripodal receptor L substituted with 3-nitrophenyl groups has been synthesized, and the binding affinity for a variety of anions has been studied by 1H NMR titrations and nuclear Overhauser enhancement spectroscopy experiments in dimethyl sulfoxide-d6. As investigated by 1H NMR titrations, the receptor binds an anion in a 1:1 binding mode, showing the highest binding and strong selectivity for sulfate anion. A competitive colorimetric assay in the presence of fluoride suggests that the sulfate is capable of displacing the bound fluoride, showing a sharp visible color change. The strong affinity of L for sulfate was further supported by UV–vis titrations and density functional theory (DFT) calculations. Time-dependent DFT calculations indicate that the fluoride complex possesses a different optical absorption spectrum (due to charge transfer between the fluoride and the surrounding ligand) than the sulfate complex, reflecting the observed colorimetric change in these two complexes. The receptor was further tested for its biocompatibility on primary human foreskin fibroblasts and HeLa cells, exhibiting an excellent cell viability up to 100 μM concentration.