Deficiency of ubiquitin-specific peptidase 18 (USP18) is a severe type I interferonopathy. USP18 down-regulates type I interferon signaling by blocking the access of Janus-associated kinase 1 (JAK1) ...to the type I interferon receptor. The absence of USP18 results in unmitigated interferon-mediated inflammation and is lethal during the perinatal period. We describe a neonate who presented with hydrocephalus, necrotizing cellulitis, systemic inflammation, and respiratory failure. Exome sequencing identified a homozygous mutation at an essential splice site on
. The encoded protein was expressed but devoid of negative regulatory ability. Treatment with ruxolitinib was followed by a prompt and sustained recovery. (Funded by King Saud University and others.).
Abstract Viral genetic diversity presents significant challenges in developing antivirals with broad-spectrum activity and high barriers to resistance. Here we report development of proteolysis ...targeting chimeras (PROTACs) targeting the dengue virus envelope (E) protein through coupling of known E fusion inhibitors to ligands of the CRL4 CRBN E3 ubiquitin ligase. The resulting small molecules block viral entry through inhibition of E-mediated membrane fusion and interfere with viral particle production by depleting intracellular E in infected Huh 7.5 cells. This activity is retained in the presence of point mutations previously shown to confer partial resistance to the parental inhibitors due to decreased inhibitor-binding. The E PROTACs also exhibit broadened spectrum of activity compared to the parental E inhibitors against a panel of mosquito-borne flaviviruses. These findings encourage further exploration of targeted protein degradation as a differentiated and potentially advantageous modality for development of broad-spectrum direct-acting antivirals.
Arteriviruses infect a variety of mammalian hosts, but the receptors used by these viruses to enter cells are poorly understood. We identified the neonatal Fc receptor (FcRn) as an important ...pro-viral host factor via comparative genome-wide CRISPR-knockout screens with multiple arteriviruses. Using a panel of cell lines and divergent arteriviruses, we demonstrate that FcRn is required for the entry step of arterivirus infection and serves as a molecular barrier to arterivirus cross-species infection. We also show that FcRn synergizes with another known arterivirus entry factor, CD163, to mediate arterivirus entry. Overexpression of FcRn and CD163 sensitizes non-permissive cells to infection and enables the culture of fastidious arteriviruses. Treatment of multiple cell lines with a pre-clinical anti-FcRn monoclonal antibody blocked infection and rescued cells from arterivirus-induced death. Altogether, this study identifies FcRn as a novel pan-arterivirus receptor, with implications for arterivirus emergence, cross-species infection, and host-directed pan-arterivirus countermeasure development.Shaw et al identify the neonatal Fc receptor (FcRn) as a host factor required for infection of cells by several divergent arteriviruses, and demonstrate that anti-FcRn antibodies can be used to block arterivirus infection.
Abstract
ISG15-deficient humans exhibit permanent, low-level expression of antiviral effectors that safely protect them from various viruses. Because the murine ISG15 axis functions differently, we ...identified animal models that recapitulate the human condition for the development of ISG15-targeting broad-spectrum antivirals. Canine, porcine, and rhesus macaque ISG15, such as human ISG15, stabilize USP18, a potent inhibitor of type I interferon (IFN)-I. Type I Interferon-primed ISG15-knockout porcine and rhesus cells demonstrate enhanced ISG expression and protection against vesicular stomatitis Indiana virus infection compared with wild type. Collectively, we unveil the interspecies diversity of the ability of ISG15/USP18 axis to control IFN-I signaling and reveal the therapeutic potential of ISG15-deficient porcine and rhesus models.
Loss of ISG15 in humans leads to increased resistance to all viruses tested. We identify rhesus macaques, pigs, and dogs as species where this mechanism is also conserved that renders them optimal models for development of broad-spectrum antivirals targeting ISG15/USP18.
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•Designed an upconversion hybrid nano fluorescent sensor for monitoring the Lactate Dehydrogenase inhibitor efficacy.•Demonstrated the practicability through evaluating Lactate ...Dehydrogenase inhibitor efficacy in diverse cell lines.•The nanosensor can distinguish the healthy and cancer cells.•Beneficial for accelerating drug screening and development.
High Lactate Dehydrogenase (LDH) activity, a distinct feature of cancer cells, is a possible causative factor for cancer cells to metastasize, infiltrate, invade, and deteriorate. The exploration of upconversion hybrid nano fluorescent sensor (HNFS) with the capability of evaluation the LDH inhibitors efficacy will be useful to accelerate the development of anti-cancer drugs from LDH inhibitors. Herein, we design an HNFS that can evaluate the inhibitors efficacy in vitro from the changes of the upconversion luminescence in the red-light region. HNFS is composed of two components: a Nile Blue A derivative (CPNB) that detects LDH activity, and tailored manganese doped upconverting nanoparticles that produce bright red emission which absorbs by CPNB via Förster resonance energy transfer. The cytotoxicity of HNFS in living cells (HeLa, A549 and Ges-1) was investigated by using the CCK-8 assay, which showed that HNFS possesses excellent biocompatibility. After incubating HNFS with three types of cells (A549, HeLa, and Ges-1), the mean fluorescence intensities of confocal images in vitro can illustrate the efficacy of LDH inhibitors to different cancer cells and distinguish healthy cells (Ges-1) from cancer cells (A549 and HeLa). Therefore, the systematic study of HNFS in vitro does encourage the potential applications of evaluating the LDH inhibitors efficacy in cancer cells.
Type I interferonopathies are monogenic disorders characterized by enhanced type I interferon (IFN-I) cytokine activity. Inherited USP18 and ISG15 deficiencies underlie type I interferonopathies by ...preventing the regulation of late responses to IFN-I. Specifically, USP18, being stabilized by ISG15, sterically hinders JAK1 from binding to the IFNAR2 subunit of the IFN-I receptor. We report an infant who died of autoinflammation due to a homozygous missense mutation (R148Q) in STAT2. The variant is a gain of function (GOF) for induction of the late, but not early, response to IFN-I. Surprisingly, the mutation does not enhance the intrinsic activity of the STAT2-containing transcriptional complex responsible for IFN-I-stimulated gene induction. Rather, the STAT2 R148Q variant is a GOF because it fails to appropriately traffic USP18 to IFNAR2, thereby preventing USP18 from negatively regulating responses to IFN-I. Homozygosity for STAT2 R148Q represents a novel molecular and clinical phenocopy of inherited USP18 deficiency, which, together with inherited ISG15 deficiency, defines a group of type I interferonopathies characterized by an impaired regulation of late cellular responses to IFN-I.
Abstract Nanoparticles are regularly used as contrast agents in bioimaging. Unlike other agents such as composite materials, nanoparticles can also be used for treating as well as imaging disease. ...Here we synthesized lanthanide functionalized gold nanoparticles that can be used for both imaging and therapy in vivo . That is a multifunctional nanoplatform was developed based on a simple and versatile method, by incorporating 10-nm gold nanoparticles and lanthanide ions (Gd3+ and Yb3+ ), denoted as LnAu nanoparticles hereby. The LnAu nanoparticles were then surface-modified using a PEGylated amphiphilic polymer (C18 MH-mPEG), and the resulting PEG modified LnAu nanoparticles (PEG-LnAu) display good monodispersion in water and good solubility in biological media. Due to the low toxicity in vitro and in vivo (as determined by a cell viability assay and histological and serum biochemistry analysis), the PEG-LnAu nanoparticles can be successfully applied to in vivo magnetic resonance imaging (MRI), in vivo computed tomography (CT) imaging and photothermal therapy (PTT) for tumor-bearing mice. Therefore, the present work developed an easy yet powerful strategy to combine lanthanide ions and gold nanoparticles to a unified nanoplatform for integrating bioimaging and therapy.
Many autoimmune diseases exhibit a strikingly increased prevalence in females, with primary Sjögren’s syndrome (pSS) being the most female-predominant example. However, the molecular basis underlying ...the female-bias in pSS remains elusive. To address this knowledge gap, we performed genome-wide, allele-specific profiling of minor salivary gland-derived mesenchymal stromal cells (MSCs) from pSS patients and control subjects, and detected major differences in the regulation of X-linked genes. In control female MSCs, X-linked genes were expressed from both paternal and maternal X chromosomes with a median paternal ratio of ~ 0.5. However, in pSS female MSCs, X-linked genes exhibited preferential expression from one of the two X chromosomes. Concomitantly, pSS MSCs showed decrease in
XIST
levels and reorganization of H3K27me3
+
foci in the nucleus. Moreover, the
HLA
-locus-expressed miRNA
miR6891-5p
was decreased in pSS MSCs.
miR6891-5p
inhibition in control MSCs caused
XIST
dysregulation, ectopic silencing, and allelic skewing. Allelic skewing was accompanied by the mislocation of protein products encoded by the skewed genes, which was recapitulated by
XIST
and
miR6891-5p
disruption in control MSCs. Our data reveal X skewing as a molecular hallmark of pSS and highlight the importance of restoring X-chromosomal allelic balance for pSS treatment.
Key messages
X-linked genes exhibit skewing in primary Sjögren’s syndrome (pSS).
X skewing in pSS associates with alterations in H3K27me3 deposition.
pSS MSCs show decreased levels of miR6891-5p, a HLA-expressed miRNA.
miR6891-5p inhibition causes H3K27me3 dysregulation and allelic skewing.
Interferon-stimulated gene 15 (ISG15), which encodes a ubiquitin-like protein, was conventionally considered as an antiviral effector due to its type-I-interferon (IFN-I)-inducible nature. Recent ...human data suggest that it primarily serves to downregulate IFN-I signaling via stabilization of ubiquitin specific peptidase 18 (USP18), the bona fide negative regulator of the IFN-I pathway. Fibroblasts derived from ISG15-deficient individuals not only exhibited low levels of USP18 and a persistent increase in IFN-stimulated gene (ISG) expression, but also enhanced resistance to a wide range of viruses, all of which was not observed in mice due to the inability of murine ISG15 to stabilize murine USP18. In this thesis work which primarily aims to reveal the evolution pattern of ISG15 as a negative regulator of IFN-I signaling in mammals, I identified canine, swine, and rhesus macaque as species in which ISG15 also protects USP18 from proteasomal degradation using a biochemical screening assay for stable ISG-USP18 interaction. I further showed that IFN-primed ISG15-deficient rhesus macaque and porcine cells demonstrated elevated ISG expression that rendered the cells more resistant against VSV infection compared to wildtype cells. The capability of rhesus macaques and swine to recapitulate human biology with respect to the ISG15/USP18 axis render them a more suitable model system than mice for developing ISG15- or USP18-targeting small molecules into broad-spectrum antiviral drugs.
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